VOLUME 4 ISSUE 1
InflammationQuenching the Fire WithinAdvancesI N O R T H O M O L E C U L A R R E S E A R C H
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research-driven botanical integrative orthomolecular innovative
InflammationA Double-Edged Sword
Inflammation and Diseasechronic inflammation as a factor in the progression of cancer, diabetes, cardiovascular disease
Natural Solutions for InflammationTargets of InflammationNatural Anti-inflammatory Agents A Note on Bioavailability
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Volume 4 Issue 1
Inflammation:A Double edged sword
Inflammation and Disease
Natural Solutions for Inflammation
Digital version of this magazine and back issues are available online at www.AOR.ca
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ADVANCEDORTHOMOLECULAR RESEARCH
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INFLAMMATIONA Double edged sword
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Epidermis (skin)
Mast Cell
Blood Vessel
Macrophage
Plasma
Injury
Bacteria
Mast cells produce histamine and other chemicals in response to trauma. This initiates the in�ammatory response
Plasma leaks from the blood vessels into the a�ected area, causing swelling and delivering clotting proteins and other healing factors
White blood cells called Macrophages move out of the blood vessels and consume bacteria and other cellular debris
Blood vessels dilate, bringing more blood to the damaged or infected site. This causes redness and heat
Understanding InflammationInflammation is a double-edged sword; it plays an important and beneficial role in the body, but it can also be very dangerous, causing damage to the body and ultimately leading to disease and even death! Whether inflammation will be beneficial or harmful depends on its type and duration. In general, there are two distinct categories of inflammation: acute or short term inflammation and chronic or long term inflammation. While short term inflammation plays a beneficial role in the body, long term or chronic inflammation can be very harmful. These harmful effects will be examined in more detail in a subsequent section. First, it is important to discuss the role of inflammation in the body. If inflammation can be so dangerous, why does it occur in the first place?
Inflammation plays a vital role in the repair process following injury or infection. Without inflammation, disease and damage would quickly progress beyond the body’s ability to recover, and death would result quickly. The body initiates the repair process almost instantaneously upon injury. It is a highly intricate process that involves a complex cascade of processes, many of which proceed concurrently, and many different players including cells and soluble factors (chemicals called chemokines and cytokines) that work synergistically with each other in a very specific manner (see Note: What are Cytokines?).
There are five key characteristics of inflammation, which we have all experienced when we get a cut or a sprained
ankle: swelling, pain, redness, heat and loss of function. Each of these characteristics is the result of the body’s efforts to protect the damaged area and to speed up healing and repair. More details about these five characteristics are included in Table 1.
The Inflammatory Response: An Overview
In a nut shell, inflammation is a system of information with multiple check points where a decision making process
Inflammation is a double-edged sword. While it plays an important role in healing and repair, chronic inflammation can be deadly!
Figure 1. The Inflammatory response
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must occur. The body reacts to challenges like foreign invaders or trauma much in much the same way that a computer makes decisions based on a “yes” or “no” format. The body’s inflammatory response is controlled by the immune system, and is part of what is called the innate or non-specific defense system. It is referred to as non-specific, because unlike the body’s specific immune defenses, it does not target specific viruses or pathogens; instead, it acts in a non-specific manner to deal with a wide variety of threats or injuries. The inflammatory response is initiated as a response to trauma, chemical agents or microbial pathogens, and is a highly programmed cascade of actions that occurs immediately in order to prevent the spread of pathogens, minimize further damage to cells and tissues and to promote repair and healing. When damage, trauma or infection occurs, cells in the tissue called mast cells will produce certain chemicals, including histamine. Histamine is a key chemical trigger of the body’s inflammatory response. The presence of histamine and other chemical factors causes the initiation of three key inflammatory processes: vasodilatation (widening of the blood vessels) in the affected area, increased permeability of the blood vessel, and a movement of
Cytokines are small protein molecules that play a key role in cell signaling, that is, they act as cellular messengers, with different cytokines providing different messages to cells about how they should act or react in various situations. Cytokines are produced by cells of the nervous system and also by cells of the immune system, especially
macrophages. Cytokines act by binding to surface receptors on other cells, where they initiate a specific response. For example, a cytokine may cause a cell to start producing certain proteins or molecules, or even to produce more cytokines. Cytokines may also be inhibitory and reduce the production of proteins or other cytokines. In this way, the interplay
of different cytokines is involved in the regulation and progression of various cellular responses in the body, including the inflammatory response.
Cytokines that play key roles in the inflammatory process are often referred to as inflammatory cytokines. Cytokines can be further broken down into three general categories: chemokines, interleukins and lymphokines. Chemokines are chemicals that attract cells to other cells or a certain area. For example, chemokines are responsible for attracting phagocytes from the blood stream to damaged areas as part of the inflammatory response. Interleukins (abbreviated as IL) were initially described as cytokines produced by leukocytes, but now this category includes a broad range of different signaling molecules involved in the immune response. Many interleukins play a very important role in the mediation of inflammation in the body. Finally, lymphokines are produced by cells called lymphocytes, and are generally involved in the body’s immune response.
Many pharmaceutical drugs for inflammation target only one mechanism of action. In contrast, natural anti-inflammatory agents like curcumin have multiple mechanisms and a more balanced effect
What are Cytokines?
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white blood cells from the blood to the damaged area (Figure 1).
Vasodilation of the blood vessels in the affected or damaged area brings more blood to the affected area. This causes redness and heat, but the main purpose of this is to supply more immune system cells and other factors to aid in healing and repair. Next, the walls of the blood vessels become more permeable, causing plasma to leak out of the blood vessels and into the affected area. This causes swelling or edema, can lead to pain due to increased pressure, and can impede the function of joints or muscles. The reason for this leakage is that the plasma contains proteins and other factors that are critical for the initiation of healing. For example, the plasma contains clotting proteins and other proteins that stimulate the body’s immune system to destroy bacteria. Finally, white blood cells called phagocytes will move out of the blood vessels and migrate to the affected site. These important immune system cells will consume and destroy bacteria and pathogens in the infected area, as well as cleaning up dead cells and other cellular debris during the healing process (Figure 1).
The above description outlines how inflammation is initiated and progresses, leading to eventual healing. In most cases, the inflammatory response is then complete, and things go back to their normal state. However, although this short-term inflammatory process is essential for healing and repair, in some cases the inflammation process does not stop, and it continues on in a long term cycle of chronic inflammation. This chronic inflammation is not beneficial; it can actually cause even more damage and can eventually contribute to the development of various diseases. The same process that the body uses to defend itself during short-term inflammation backfires when it becomes chronic and ends up harming the body. It is much like an army that turns on the citizens and the country it was meant to defend! In fact, many diseases have now been linked
to inflammation, for example, heart disease, stroke, diabetes, liver disease, and even obesity, among others! Although acute inflammation is a vital process, scientists and physicians are beginning to understand that there is a very real need to bring a stop to this long- term inflammation
The inflammation process is highly complex, however, in general, we can think of inflammation as being
divided into short-term and long-term types. If short-term inflammation is beneficial and long term inflammation is unhealthy, the key question is: at what stage does the balance tip? When does inflammation turn from being beneficial to harmful? And most importantly, when should we intervene? For example, if one were to intervene immediately upon the onset of inflammation, theoretically
Table 2. Comparison between Acute and Chronic Inflammation
Acute Inflammation Chronic Inflammation
Cause Pathogens, injured tissues Persistent acute inflammation, persistent foreign bodies, or autoimmune reactions
Onset Immediate Delayed
Duration A few days Up to many months or years
Cells Involved neutrophils (primarily), eosinophils, basophils , monocytes, macrophages
monocytes, macrophages, lymphocytes, plasma cells, fibroblasts
Outcome Healing, abscess formation or chronic inflammation
Tissue destruction, disease
Table 1. The Five Key Characteristics of Inflammation
1. Swelling Caused by an accumulation of fluid and pus called edema.
2. Pain Serves as a warning signal to help prevent further injury.
3. Redness Caused by increased blood flow to the area. This occurs as the body tries to improve its defenses at the site of injury by delivering the key cellular players and soluble factors to initiate repair.
4. Heat The injured area is warm to the touch since more blood is being delivered. Also raising the temperature acts as a defensive measure by eliminating and/or preventing infection.
5. Loss of Function This is generally temporary and is a precautionary measure to allow the damaged part to heal quickly. For example, the inability to move a body part like a sprained ankle.
The same process that the body uses to defend itself during short-term inflammation backfires when it becomes chronic and ends up harming the body
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one would be preventing the body from doing its job of protection! This is where the checkpoints come in. These checkpoints involve feedback and actions from the body’s immune system, which is the great orchestrator of the inflammatory process. At some stage in the inflammatory process, the body’s immune system will decide, based on the evidence available and feedback from key cells, that a certain checkpoint has been reached and will proceed with a specific course of action based on this information. It is these check points that ultimately determine the fate of the inflammatory process.
Unfortunately, as of now, no definite signs or symptoms have been identified that could be used to indicate that a critical checkpoint has been reached and that the balance is about to tip from beneficial to harmful inflammation. This knowledge would certainly make the lives of physicians much easier as they would be better able to identify at what precise point to intervene. Fortunately, biological chemistry comes to the rescue as various biomarkers or “markers of inflammation” have been identified that can be used to help us make this decision. Whilst these markers do not provide a perfect solution, they are a
very useful aid in making the decision of how and when to intervene with treatment for an inflammatory condition. Measurement of various biomarkers like NF-KB, CRP, COX, LOX, IL-6 and others (which will be discussed in greater detail in a later section) as well as the presence of various cells and inflammatory gene products are useful markers that are used in the decision of when to act in the treatment of inflammation.
Treating InflammationIn the pharmaceutical world we have a class of drugs called non steroidal anti-inflammatory drugs (NSAID’s) that are often used to treat inflammation. These include drugs like the commonly used over-the-counter ibuprofen or the more powerful COX-2 inhibitors like Celebrex. Unfortunately, these drugs are associated with many unpleasant side-effects, including gastrointestinal problems or bleeding, heartburn and even kidney or cardiovascular complications. In fact some of these drugs, like Vioxx for example, have
been withdrawn from the market. Fortunately, the natural world offers powerful and effective yet safe alternatives which can meet the challenges of inflammation.
Unlike the pharmaceutical drugs that act solely on a “silver bullet” model, meaning that they usually have only one mechanism of action, natural products often have multiple mechanisms of action. This is important because inflammation is a process that acts through numerous pathways. Therefore, dealing with only one pathway will never address the situation effectively; it is not going to put out all of the fires. Generally, the more pathways that are blocked, the more effective the treatment is likely to be. Moreover, natural products tend to be less potent but more “balanced” in their action because they often contain additional molecules that support the major compounds in performing their actions. Several natural solutions for inflammation and their mechanisms of action are discussed in detail in a later section of this magazine.
Fortunately, the natural world offers powerful and effective yet safe alternatives which can meet the challenges of inflammation
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More and more studies are showing the potentially damaging effects of chronic inflammation and its link to the development of various serious chronic diseases. Research has now identified chronic inflammation as a factor in the progression of cancer, diabetes, cardiovascular disease and Alzheimer’s disease, along with many others! The link between inflammation and these diseases is discussed in the following sections.
Inflammation and CancerIn his 1971 State of the Union address President Richard Nixon pledged “I will ask for an appropriation of an extra $100 million to launch an extensive campaign to find a cure to cancer. Let us make a total national commitment to conquer this dread disease. America has long been the wealthiest nation in the world. Now it is time we become the healthiest nation in the world”. This appropriation led to the creation of the National Cancer Institute (NCI). Since then over 200 billion dollars have been spent, 1.56 million papers published, and 150,855 studies in mice reported. In spite of this, the US cancer death rate was the same in 2002 as it was in 1950 (193.9 per 100,000 versus 193.4 per 100,000)! Hopefully, however, research will continue, and we
will move closer to finding the key to this deadly disease. There is evidence that chronic inflammation is an important contributing factor.
In general, cancers are a chronic disease caused by the prolonged exposure to a long list of damaging stimuli. These stimuli can include: infections or toxins like aflatoxin, hormonal insult like excess estrogen exposure post menopause, chronic irritation from tobacco smoke, carcinogens or asbestos exposure, a diet high in fats or sugar, alcohol, radiation and many more. In the early 1860’s the renowned German pathologist Rudolf Virchow mentioned that certain cancers seemed to occur at sites of chronic inflammation. He based his hypothesis on the fact that certain irritants, together with long standing tissue injury invoked inflammation that ultimately led to cancer. In fact, all of the damaging stimuli listed above could contribute to chronic inflammation. There is a significant body of evidence demonstrating that chronic inflammation over a long period of time (20-30 years) can lead to cancer. For example, inflammation of the bronchus (bronchitis) due to the constant irritation from tobacco smoke can lead to cancer of the lung. Similarly, inflammation of the bladder (cystitis), colon (colitis), esophagus (esophagitis)
and liver (hepatitis) leads to cancers of these tissues. Unfortunately, in the 1860’s this link between inflammation and cancer was considered too bold and largely went ignored.
Recently, however, studies conducted in large groups of people have reinforced Virchow’s original observation suggesting a strong relationship between stimulators of inflammation and cancer. These epidemiological studies have identified stimulators of inflammation in the form of chronic irritants like tobacco smoke, alcohol, fried foods, UV light, infections, stress, red meat, grilled food, various heavy metals, solvents and trauma as major risk factors in various types of cancer. For example, the human papilloma virus has been linked to cervical cancer and chronic viral hepatitis B and C (HBV and HBC) infections have been identified as major risk factors for a specific liver cancer called hepatocellular carcinoma. Similarly, the bacteria Helicobacter pylori which is widely present in the stomach of most people world-wide and has a propensity to burrow its way into the lining of the stomach wall, is not only a primary contributor to the development of ulcers, but has also been strongly linked to the development of stomach cancer. Other chronic infections and/or inflammation like inflammatory bowel disease (IBD) also increase the risk of cancer of the colon. In fact it is estimated that approximately 15-20% of all human cancers are linked to infection and/or inflammation!
Perhaps the best evidence for the significance of inflammation during cancerous growth comes from long term users of aspirin and non-steroidal anti-inflammatory drugs. Recent data indicates that these drug users reduce colon cancer risk by 40-50% and they also may be preventive for other cancers including lung, esophagus and stomach cancers. Additionally, other stronger NSAID’s have been shown to prevent the metastases or spread of certain forms of cancer. A summary of the cancers linked to chronic inflammation is listed in Table 3.
Inflammation and Disease
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Inflammation is rightly regarded as a “secret killer” in diseases such as cancer. It is clear that there is a link between the two. However, this begs the question, how is inflammation linked to cancer? What is the mechanism of action? Which cellular processes are involved? If we can understand these things then perhaps we can use specific nutrients to target the key molecules or mechanisms that are involved in the development of cancer.
Cancer is a multistage process defined by at least three main stages: initiation, promotion, and progression (Figure 2). These stages can then be further subdivided into various steps, including cellular transformation (where cells change their look and behaviour), promotion, survival, proliferation (multiplication of cells), invasion, angiogenesis (formation of blood vessels so that the tumour can be continually fed and grow), and metastasis (spreading of cancer to distant sites). These stages, while distinct, overlap considerably and involve various players like initiating compounds, signaling molecules, growth factors and numerous other mediators in a complex role play that links chronic inflammation to all of these stages. A list of these various signaling molecules, growth factors and other key players linking inflammation and cancer are described in Table 4, and their actions in the body and their contribution to inflammation and cancer initiation are shown in Figure 3.
These molecular players are legitimate targets for the anti-cancer effects of various nutrients. For example, it has been shown that certain anti-inflammatory agents like the non-steroidal anti-inflammatory drugs (NSAID’s) reduce chronic inflammation and thus reduce the incidence of various cancers. Unfortunately, some of these NSAID’s are themselves harmful, and cause side-effects like gastric irritation and liver and kidney toxicity. However, it is possible that certain natural compounds could target such pathways without having the associated side-effects and thus could be used to help prevent or reduce the incidence of cancer.
Inflammation can work both ways with short term inflammation being protective and having anti-cancer effects, while long term inflammation can cause cancer. The intent of many natural products is to reduce chronic inflammation by targeting one or more of the above pathways that involve
numerous inflammatory players including NF-κB, which plays an enormous role in inflammation and is discussed in greater detail in the next article, as well as various cytokines, chemokines, growth factors and hormones. For example, it has been noted that NF-κB is raised in every
NORMAL CELL
INITIATION PROMOTION PROGRESSION
MUTATED CELLMALIGNANT
TUMOR
The mutated cell is stimulated to proliferate rapidly , producing more
mutated cells
Mutation and rapid division continue. A malignant tumor
forms. Eventually can spread to other parts of the body by
metastasis
A Carcinogenic Agent (chemicals, radiation, viruses) causes DNA
damage and mutation
Table 3. Cancers Linked to Chronic Inflammation (Adapted from Maeda and Omata, 2008)
Infection Related Conditions Tumour Type Causative Agent
Tuberculosis Lung Cancer Mycobacterium tuberculosis
Chronic Gastritis Gastric Cancer Helicobacter pylori
Chronic Hepatitis Hepatocellular Carcinoma Hepatitis B or C virus
Mononucleosis Lymphoma Epstein-Barr virus
Chronic Cervitis Cervical Cancer Papilloma virus
Non-Infection Related Conditions Tumour Type Causative Agent
Asbestosis Lung Cancer, Mesothelioma
Asbestos
Reflux Esophagitis Esophageal Cancer Gastric Acid
Chronic Pancreatitis Pancreatic Cancer Alcohol
Inflammatory Bowel Disease Colon Cancer Ulcerative ColitisCrohn’s Disease
Skin Inflammation Melanoma UV light
Figure 2. The Stages of Tumour Development
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inflammatory condition, with especially strong links to cancer. Bharat Aggarwal of The University of Texas M.D. Anderson Cancer Center in Houston, Texas is one of the foremost researchers on NF-κB and its association with cancer. After thirty years of research, Aggarwal is convinced that NF-κB is the key culprit in cancer. According to Aggarwal all roads to cancer go through this single molecule!
Several lines of evidence points to the key role NF-κB plays in inflammation and cancer. NF-κB has been associated with every known carcinogen and has also been linked
with other inflammatory mediators like COX-2 and 5-LOX enzymes, tumour necrosis factor (TNF) and others. Furthermore, NF-κB levels are dramatically reduced by anti-cancer agents like natural polyphenols, flavonoids, vitamin E, lycopene, vitamin C and many others. All these findings provide compelling evidence that NF-κB is likely a major mediator of cancer.
Inflammation and DiabetesThe association between a
reduced production of insulin and type-2 diabetes has been considered the hallmark of this condition. This
reduction in insulin production causes an inability of insulin to transport sufficient quantities of glucose from the blood and into the tissues. The net result of this is that glucose is excreted into the urine. In fact, early physicians remarked that the high sugar content of the urine produced by diabetic patients could be used as a diagnostic marker of the disease.
The insulin producing cells are called Beta cells and they are located in the islets of Langerhans in the pancreas. In diabetic patients, these Beta cells are either destroyed during the course of the disease and/or are unable to be regenerated quickly to produce sufficient quantities of insulin to handle the body’s requirements. However, type-2 diabetes is not only associated with a decreased production of insulin but also with a more recently discovered phenomenon called insulin resistance. Insulin resistance is a condition in which insulin becomes less effective at lowering glucose levels in the body even when it is present at normal levels.
Type-2 diabetes is associated with a number of long term consequences including atherosclerosis or hardening of the blood vessels which leads to poor circulation and a loss of vessel elasticity as well as eventual heart disease and high blood pressure. Furthermore, diabetes can also affect smaller vessels, like those in the eyes, kidneys and the central nervous system, causing retinopathy, nephropathy and neuropathy which results in damage to the nerves, kidneys and blindness.
Several theories have been proposed to help explain why some individuals develop inadequate insulin production and insulin resistance. One of the most credible of these theories is inflammation. The link between inflammation and type-2 diabetes has become increasingly strengthened by the results of numerous scientific studies in both animals and humans. There are several factors that may induce chronic inflammation in the body. Those most critical to the development of type-2 diabetes are shown in Table 5.
Table 4. Key Molecular Players Linking Inflammation to Cancer(Adapted from Lu et al., 2006)
Molecule Function linking Inflammation to Cancer
IL-6 (cytokine) Promote tumour growth
TNF-α (cytokine) Induce DNA damage and inhibit DNA repair, Promote tumour growth, Induce angiogenic factors
Chemokines Promote tumour cell growth, Facilitate invasion and metastasis by directing tumour cell migration and promoting basement membrane degradation
NF-κB Mediate inflammation, promote chronic inflammation, promote production of mutagenic reactive oxygen species, protect transformed cells from apoptosis, promote tumour invasion and metastasis, feedback loop between pro-inflammatory cytokines
iNOS Downstream of NF-κB and pro-inflammatory cytokines, induce DNA damage, regulate angiogenesis and metastasis
COX-2 Produce inflammation mediators, promote cell proliferation, anti-apoptotic activity, angiogenesis, and metastasis
HIF-1α Promote chronic inflammation, induced by pro-inflammatory cytokines, contribute to angiogenesis, tumour invasion, and metastasis
STAT3 Activated by pro-inflammatory cytokines, promote proliferation, apoptosis resistance, and immune tolerance
Nrf2 Anti-inflammatory activity, protect against DNA damage
NFAT Regulate pro-inflammatory cytokine expression, required in cell transformation
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Microbial Infection, Chemical Irritation, Injury
Acute In�ammation
Chronic In�ammation
In�ammatory CellsReactive Oxygen Species
iNOS and COX-2
In�ammatory Environment in the Body
HIF-1α
Chemokines
Resolution of In�ammation
DNA Damage & Mutation
Other In�ammatory Mediators (e.g. NF-kB, NFAT, STAT3)
Pro-In�ammatory Cytokine (e.g. TNF-a, IL-1,IL-6)
Hypoxia (Low Oxygen)
Tumour Initiation Tumour Promotion Tumour ProgressionTumour Invasion &
Metastasis
Helicobacter pylori
Papilloma virus
Infectious Agents
In�ammatory Agents
Carcinogens that Activate NF-κB
NF-κB
Hepatitis B or C virus
Epstein-Barr Virus
UV Obesity
Stress
Drug Use
Cigarette Smoke
Alcohol
Poor Diet
Diesel
Ozone
Heavy Metals
DBMA
Radiation
TNF IL-1 IL-17 IL-18 H2O2 PMA
Figure 3. Summary of mechanisms for the involvement of inflammation in cancer development. For more information see Table 4. (Adapted from Lu et al., 2006)
Figure 4. NF-κB, a key inflammation inducing molecule is activated by a large number of carcinogens, and is thought to play a major role in the development of cancer. (Adapted from Ralhan et al., 2009)
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There are several lines of evidence that implicate inflammation in the development of diabetes. The strongest is data from both animal and human studies that shows raised levels of key inflammatory markers like C-reactive protein (CRP) or certain interleukins like IL-1B or IL-6 in patients or animals with Type-2 diabetes. Moreover, these studies have shown that the higher the levels of these inflammatory markers, the greater the chance the individual has diabetes. In fact, it has been argued that raised levels of these inflammatory biomarkers indicated
that inflammation also results in the activation of the immune system, which may then actually attack various tissues of the body. Diabetes specialists call this auto-inflammatory disease which is similar to an auto-immune disease in that it results in the body attacking its own tissues; the difference is that the primary cause of an auto-inflammatory disease is inflammation. The second strong evidence of a link between inflammation and type-2 diabetes comes from biopsies of various tissues that show clear evidence of inflammatory cell involvement.
Despite the overwhelming evidence of the involvement of inflammation in diabetes, it remains uncertain whether inflammation is a cause of the disease or whether it is a resulting symptom. It is a classic case of a chicken or the egg scenario, which are so common in biological science. If inflammation is in fact a cause of diabetes, then we must examine the mechanisms by which this occurs. That is, how can inflammation cause type-2 diabetes? Research in this area has suggested that inflammation may lead to diabetes by causing cell death and by creating hypoxic conditions; this means that inflammation causes an environment in which the tissues are literally starved for oxygen, leading to cellular death.
Multiple mechanisms may contribute to increased inflammation in type-2 diabetes, some of which are quite general and others that are highly specific. In the pancreas, inflammation may be initiated by excessive nutrients like glucose or free fatty acids that can activate the immune system (see Table 5). There are a large number of biochemical pathways and molecules that are implicated in the inflammatory process; however, as with cancer, the most extensively studied of these in diabetes is the NF-κB pathway.
Treatments to Reduce Inflammation in Type-2 DiabetesEvidence for the role of inflammation in type-2 diabetes is quite strong and new treatments that block the activation of various inflammatory markers like NF-κB or interleukin are actively being developed. Research is beginning to show that an anti-inflammatory approach to treatment of the disease seems to lower blood glucose levels and improve insulin release as well as helping to limit the damaging effects that ensue. In particular, anti-inflammatory treatments appear to be very helpful for reducing the glycation of hemoglobin (also referred to as HbAC1) which is a commonly used marker for diagnosing diabetes. Glycation is a major factor
Table 5. Causes of Inflammation Linked to Diabetes
1. Oxidative Stress Oxidative stress in the pancreas and/or cellular organelles like the endoplasmic reticulum (ER) results in highly reactive oxygen and nitrogen free radicals which damage the tissue in a chain reaction or domino effect process.
2. Plaque Plaque-like deposits can form in the pancreas, much like the plaque that get deposited in the arteries. These deposits cause both destruction of the insulin producing Beta cells and also prevent regeneration of the pancreatic tissue.
3. Glucotoxicity Toxic effects of excess glucose in the body. Can cause tissue damage and disrupt the uptake of glucose by the cells.
4. Lipotoxicity Toxic effects of excess fats and increased concentrations of free fatty acids that may cause cell death.
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in the development of diabetic complications. Glycation is a chronic condition brought upon by consistently high levels of glucose in the blood. The resulting effect is that glucose molecules bind to various proteins in the body like hemoglobin or other proteins in the plasma, tissues or blood vessels. When a protein is glycated it becomes warped, which changes the structure and therefore the function of the protein. In the case of blood vessels, for example, glycation may result in a weakening of the blood vessel walls or a reduction in elasticity. These effects can lead to increased blood pressure and an increased incidence of vessel rupturing. The glycation of hemoglobin can be a major problem in diabetes.
The use of anti-inflammatory compounds in the treatment of diabetes has also been shown to improve the
release of insulin by the Beta cells. Many of these studies validate the potential of targeting inflammation as a therapeutic approach to treating type-2 diabetes and support a causative role of inflammation in this disease. Obviously more work is needed to test the effects of either single anti-inflammatory compounds or cocktails that will target the various pathways of inflammation involved in diabetes to achieve improved results. Nevertheless, there is ample evidence of a significant role of inflammation in type-2 diabetes as either the underlying cause or a resulting symptom that needs to be addressed.
Inflammation and Cardiovascular DiseaseCardiovascular disease includes a spectrum of closely related conditions
associated with the heart and circulation and is the leading cause of death in the western world. Conditions included under the umbrella of Cardiovascular Disease include: heart failure, angina, heart attacks, high blood pressure and the formation thrombi, or large blood clots, which are the primary cause of stroke.
Peter Libby of Harvard Medical School was among the first researchers to uncover a connection between inflammation and cardiovascular disease (CVD). Libby was studying atherosclerosis, a condition that results in hardening of the arteries due to the accumulation of plaque in the blood vessels. This plaque can then lead to further damage to the vessels, and a large number of cardiovascular complications including high blood pressure and heart attacks. In the
Normal ArteryBlood vessellining(endothelium)
Smooth muscle cells
Healed Ruptured PlaqueReduced blood �owFibrous vessel wall
Early Plaque Formation
Fibrous CapPlaque RupturesBlood clot (thrombus) forms
Heart Attack occursVulnerable PlaqueThin �brous capLarge lipid coreMany in�ammatory cells
Stabilized PlaqueThick �brous capSmall lipid coreBlood �ow normal
Figure 5. In early plaque formation the recruitment of inflammatory cells and the accumulation of fat leads to formation of a lipid core in the artery. Initially the artery enlarges in an outward direction to accommodate the increasing fat build-up. At this point, blood flow is largely maintained (stabilized plaque). This may be maintained if diet and lifestyle factors are improved. However, if inflammatory conditions persist, the lipid core can grow, resulting in a thinning of the fibrous cap, which can eventually rupture. When the plaque ruptures, blood that contact it will start to clot, resulting in the formation of large blood clot or thrombus. If the thrombus blocks the flow of blood through the vessel a heart attack can occur. The thrombus may also be resorbed into the blood vessel wall, resulting in a thickened, fibrous wall and a narrowed blood vessel. This narrowing can greatly restrict blood flow, resulting in conditions like angina (Adapted from Libby, 2002).
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Cholesterol is oxidized and activates the immune system, attracting monocytes, which enter the vessel wall and become macrophages
Blood Vessel
Interior of the Blood Vessel
Monocyte
Fibrous CapEndothelium (blood vessel lining)
Oxidized Cholesterol
INFLAMMATIONCytokines
Muscle Cells
Lipid core of plaque
Foam Cell
Macrophage
Macrophages induce in�ammation. They Produce in�ammatory cytokines and attract more immune cells. They consume cholesterol, becoming foam cells, a key component of atherosclerotic plaque
Cytokines stimulate proliferation of blood vessel muscle cells, expanding the artery around the growing plaque
A �brous cap forms. In�ammation continues. Eventually, the plaque may rupture, leading to clot formation and heart attack
Figure 6. The cellular basis of inflammation in the development of atherosclerosis
1970’s, most researchers had accepted that there is a connection between high fat intake and atherosclerosis. Later, it was found that the type of fat intake is also important. For example, the consumption of saturated fats and especially trans fats, is largely responsible for the development of atherosclerosis. However, researchers still lacked a clear understanding of
the sequence of events involved in the initiation of atherosclerosis.
In piecing together this sequence of events, Libby noted that immune system cells associated with inflammation, like macrophages, were the first cells to arrive at the scene of blood vessel damage. Based on this initial observation, Libby then pieced together the events of atherosclerosis,
much like a forensic scientist solving a crime. The first step of atherosclerosis involves cholesterol, which is a large molecule that in and of itself is not harmful, and has an important role in the healthy functioning of the body. For example, cholesterol plays an important role in the synthesis of various hormones (like estrogen, testosterone and stress hormones)
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and is an important component the membranes lining the cells of the body.
Unfortunately, the cholesterol molecule has a number of protruding arms called hydroxyl groups that are especially susceptible to damage by highly reactive molecules called free radicals. These free radicals include reactive oxygen and nitrogen species that commonly lurk in areas of the body that experience high levels of stress, like the blood vessels. When it is attacked by free radicals cholesterol becomes oxidized or nitrated, meaning that an oxygen or nitrogen atom is added to the molecule. It is this damaged cholesterol that is the “bad” cholesterol that gets deposited on the walls of the blood vessels as a fatty build-up. When the immune system detects this aberrant and “non-self ” form of cholesterol building up in the blood vessels it acts quickly to send the various immune cells into action. The damaged or oxidized cholesterol causes immune system cells, called monocytes to latch onto the walls of the blood vessels. These cells then migrate into the walls of the vessel, and transform into macrophages which initiate the body’s inflammatory response and begin to devour cholesterol molecules. These cholesterol filled macrophages are called “foam cells” and form the fatty lipid core of the plaque. Immune cells also act to cordon off the foreign cholesterol molecules by forming a fibrous capsule around the lipid core to help prevent it from spreading to other areas. Unfortunately, there are usually many affected areas, which results in these capsules being formed in many areas along the walls of the blood vessels.
At this point, the cholesterol filled foam cells begin to burrow deeper into the vessel wall and into the muscle layer around the blood vessel. The muscle cells in this layer respond to the aggressive expansionist behaviour by multiplying further. In the midst of this battle, other immune players send out signals to recruit more cells and immune system factors to the site of damage, and also
release various inflammatory cytokines, resulting in a continuing loop of increasing inflammation. Eventually, the plaque can rupture, leading to the formation of a blood clot, which in turn can cause a heart attack and possible death. The details of plaque formation in the arteries are shown in Figure 5.
This series of events suggests a connection between a chronic state of inflammation and the progression of atherosclerosis. Inflammation plays a role at every stage in the progression of atherosclerosis. In fact, very early atherosclerotic lesions are almost purely inflammatory in nature, consisting of a collection of fat laden inflammatory immune cells like macrophages. As atherosclerosis progresses, even more immune cells infiltrate the region of plaque formation, where they are a component of the cap covering the lipid core of the plaque. These immune cells exhibit signs of activation and release various inflammatory cytokines. When
plaque rupture occurs, this happens at areas where the cap is thinnest. These areas tend to be highly abundant in activated immune cells which produce high levels of inflammatory molecules and various enzymes that can weaken the cap and activate cells in the core. This process transforms the stable plaque into a vulnerable, unstable structure that can rupture, leading to thrombosis or clot formation.
Overall, Libby’s major contribution was to link high levels of various inflammatory markers like C-reactive protein (CRP) with the extent of inflammation and the extent of vascular damage. This connection between inflammatory markers and cardiovascular disease progression provides a series of predictive markers that may be able to be used to help identify patients with plaque build-up and the beginning stages of atherosclerosis earlier, allowing treatment to give at a an earlier stage
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of the disease. The value of these predictive, inflammatory markers has been shown in a variety of studies. Research has clearly shown that elevated inflammatory markers are associated with increased cardiovascular risk among healthy individuals as well as those at higher risk. For example, Lindahl and colleagues found that in patients with unstable coronary artery disease, levels of the inflammatory marker CRP was directly and strongly related to the long-term risk of death from cardiac causes (see Figure 7). Furthermore, various prescription drugs that are used to treat various aspects of cardiovascular disease, like statins, aspirin, fibrates and ACE inhibitors have also been shown to have the effect of reducing levels of various markers of inflammation, especially in patients with very high levels to start with.
Inflammation and Alzheimer’s DiseaseAlzheimer’s Disease (AD) is a devastating and a progressive degenerative disease of the central nervous system that dramatically affects both the patient and their care-givers. Over two thirds of all cases of dementia (memory decay, diminished reasoning and personality changes affecting all areas of daily living) are associated with AD. It is estimated that by the age of 85, between a quarter and one third of all individuals will develop AD.
How does Alzheimer’s disease Develop?Amyloid-beta precursor protein (APP) is a protein molecule composed of around 700 amino acids and is located in within the membrane of nerve cells.
An enzyme called BACE1 breaks down APP into smaller subunits, one of which is called amyloid beta peptide (Aβ). This small, 42 amino acid subunit is thought to be one of the major contributors of to the development and progression of Alzheimer’s disease. Once formed, multiple Aβ join together to form large aggregates that are even more aggressive and damaging. These Aβ aggregates produce a plaque-like deposit around the nerve cells in the brain; much like a cholesterol laden plaque in the blood vessels forms and causes atherosclerosis or damage of blood vessels.
The other possible contributing cause of AD are specific ‘tau’ proteins called neurofibrillary tangles (NFT) which also form around nerve cells. Proponents of the Aβ theory are jokingly referred to as “Baptists” while
Figure 7. Probability of death from cardiac causes in relation to the level of C-reactive protein (CRP), a marker of inflammation, in the blood (Adapted from Lindahl et al., 2000)
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those in the NFT camp are referred to as “Taoists”. Whether the main cause is Aβ or NFT, the net result is the destruction of the nerve cells. Both Aβ plaque formation and the formation of NFT are thought to stimulate localized and chronic inflammation around the affected nerve cells. Over many years, this chronic inflammation is likely to significantly exacerbate the pathogenesis of the disease. In the end, chronic inflammation combined with the generation of damaging free radical species and the destruction of synapses or “connections” between the nerve cells ultimately leads to the degeneration of the neural circuitry. The progression of Alzheimer’s disease is also accompanied by the eventual loss of brain volume or atrophy, and a loss of neurons and functional neural synapses. A theoretical progression of events involved in this process is shown in Figure 8.
The role on inflammation in Alzheimer’s may be even more nefarious than initially thought. New research shows that not only is inflammation a contributor to the progression of the disease, it may actually be one of the main causes! Two studies conducted at the Saint Louis University School of Medicine have suggested that AD occurs due to a malfunction in a transporter protein that is supposed to clear Aβ across the blood brain barrier and out of the brain. When this transporter malfunctions, the result is that Aβ accumulates in the brain, leading to AD. However, when the researchers looked further into what actually caused the transporter to malfunction, they found that the key was inflammation! When they induced inflammation in healthy mice they found that it turned off the transporter that lets Aβ exit the brain into the bloodstream. They also found that it revved up an entrance transporter that actually transported more Aβ into the brain! When the mice were given the NSAID indomethacin, the transporters went back to their normal functioning. This provides an explanation for a variety of epidemiological studies
in humans that have shown that individuals using NSAID’s over a long period of time have a reduced risk of developing Alzheimer’s disease. However, as previously discussed, the chronic use of NSAID’s comes with its own risks and side-effects. The good news is that some natural products are also beginning to show considerable promise for reducing inflammation and other symptoms associated with AD.
For example, one significant problem encountered in AD is that the Aβ is not cleared rapidly enough by the body’s phagocytes. These
specialized white blood cells have the ability of engulf and eliminate foreign molecules, cells or other debris. A recent study in humans has shown that the combination of curcumin and vitamin D was able to enhance the clearance of the Aβ by phagocytes. An interesting aspect of the study is that the two nutrients were synergetic, meaning that the effect t together was greater than the sum of their individual effects on Aβ clearance (Masoumi et al. 2009). The role and actions of curcumin and other natural anti-inflammatory agents are discussed in detail in the next article in this magazine.
Amyloid β Accumulation and Plaque Formation
OxidativeDamage
Dysfunctional signaltransduction
Failure of Phagocyticclearance
NFT Accumulation
GlutamateAccumulation
Synapse LossNeuron Loss
In�ammation
Cognitive Decline(memory loss, cognitive de�cits, agitation, depression)
Figure 8. A hypothesized sequence of events in the development of Alzheimer’s disease (Adapted from Frautschy and Cole, 2010)
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As a primary defense system of the body, inflammation is critical in both healing and repair following exposure to a wide array of diverse stimuli. These stimuli can include UV radiation from excessive sun exposure, dietary factors like foods with a high glycemic index foods or high in saturated fats, various allergens like pollen, animal dander, certain foods or cosmetics, harmful chemicals, tobacco, alcohol, stress, microbial infections, cuts, burns and many more (See Figure 9).
Short term inflammation is self-limiting and stops as quickly as it starts once healing and repair is under control. However, serious problems arise when inflammation continues and becomes a long-term condition. This can occur due to continuous provocation or exposure to inflammation-inducing stimuli (like those shown in Figure 9), the failure of this usually carefully controlled process to stop when it should, or a combination of these two factors. This results in chronic inflammation, which
is associated with a whole range of diseases from Alzheimer’s disease to Systemic Lupus Erythematosus and even obesity (see Figure 10).
It is unclear at this stage whether inflammation is the cause or the consequence. Much debate rages, nevertheless, the association is very strong, leading some researchers to state that “All roads to chronic diseases lead through inflammation”.
The inflammatory process is highly complex and proceeds in a manner that can be described as a domino-like process. The inflammatory response consists of a series of events that involve many players including various cells (mainly white blood cells), and chemicals called cytokines, chemokines, adhesion molecules, growth factors, hormones and the nervous system. The interplay between these players is not completely understood, but the end result is the classical signs of inflammation, namely heat, redness, swelling and pain,
plus the (usually temporary) loss of function of the tissue in question.
Molecular Targets for Anti-inflammatory ActionCurrently the intricate and complex process of inflammation is far from being completely understood, which means that the control of inflammation presents a huge challenge to scientists and physicians. Nevertheless, research has revealed that there are a number of cracks in the inflammatory armour that can be targeted for therapeutic purposes. Generally these include certain molecules that play key roles in the progression of inflammation. For example, some well-known inflammatory targets include: protein kinases (PK), NF-κB, tumour necrosis factor (TNF), free radicals or radical oxygen species (ROS), and cyclooxygenase (COX enzymes). The way in which each of these can be targeted to control inflammation is discussed below. It must be remembered, however, that these represent only a few players in the inflammatory cycle; there are many more possible targets and the whole process is a biochemist’s nightmare with intricate and often seemingly conflicting interactions and roles between a huge number of molecular factors and chemical signals.
Protein Kinases (PK)Protein Kinases are a very large family of enzymes including several hundred different but related enzymes. Enzymes in general act to speed up or modify the function of their target, and PK enzymes are no different. Typically PKs achieve their action through a process called phosphorylation, which means that they add a molecule called a phosphate group to their target. The process of phosphorylation changes the structure and thus the function of the enzyme’s target. For example, it is PKs that are responsible for de-activating a particular subunit of a key mediator of inflammation called NF-κB. With this subunit (called IKK) disabled, NF-κB is free to initiate inflammation by reading
20 Advances
Natural Solutions for Inflammation
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and activating key inflammatory genes. This process is discussed in more detail below.
PKs are fairly high up in the inflammatory cascade and as one of the early players in the process their job is to fine tune the carefully controlled inflammatory process. Unfortunately, despite the potential for fine control over inflammation, PKs are a huge family of enzymes, responsible for hundreds of different activities in the body. It is incredibly difficult to modulate the function of one specific PK, which means that they are not the ideal target for intervention to treat and control inflammation. Additionally, because there are so many different PKs, and at the moment researchers haven’t figured out which PK acts where. Nevertheless, many natural products do have some influence on
various PKs, which does contribute to their anti-inflammatory actions.
NF-κBNF-κB is complex four protein molecule that acts as a nuclear transcription factor, meaning that it plays a role in controlling whether certain genes are activated or inhibited. The major role of NF-κB is to read (or transcribe) the DNA code and turn on or regulate over 400 genes (out of the 30,000 that we humans have) that will produce specific protein products that play a major role in inflammation and cancer-associated pathologies like invasion, angiogenesis, proliferation and others.
NF-κB was discovered in 1986 and is one of the most researched proteins of the inflammation process. Present in every cell from the fruit fly to man, NF-
κB consists of three subunits, two of which activate genes and a third, called IKK, which is an inhibitor that keeps the other two in check. Essentially, once stimulated by any of a multitude of provocative stimuli (see Figure 9) enzymes called protein kinases (PKs) inactivate the inhibitor protein IKK, which frees the two active subunits. The active subunits then move from the cell towards the nucleus where they act to read hundreds of different genes associated with inflammation. Once read, the genes become active, producing a series of downstream products including proteins, receptors, enzymes and other factors like TNF, COX, LOX, IL-2 and others. These products then instigate and sustain the inflammatory process.
NF-κB levels are raised in every inflammatory condition including
In�ammation
Harmful SoleventsSolventsGasoline
Pesticides, etc.
AllergensPollen, Foods
Pet DanderCosmetics etc.
Tobacco Smoke &
Alcohol
Stress
InjuryCuts
Burns Sprains
Infections Fungi
Bacteria Viral
Unhealthy Diet High Sugar
High Saturated or Trans Fats
UV Radiation
Figure 9. Stimuli for Inflammation
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heart disease, diabetes, allergies, asthma, various forms of arthritis (osteo and rheumatoid), Crohn’s disease, multiple sclerosis, Alzheimer’s disease, osteoporosis and many more (See Figure 10). Unlike PKs, NF-κB is farther down in the process and is thus “closer” to the scene of action. The advantage of targeting NF-κB is three-fold: first, it is a key molecule that can read the inflammatory script allowing expression of various inflammatory genes, second, NF-κB is very well researched and has shown a strong correlation with virtually all inflammatory diseases and third, NF-
κB, unlike PKs, is a single molecule, which allows it to be manipulated without significantly affecting other pathways.
TNF-alphaTNF-α, or Tumour Necrosis Factor alpha, is a molecule that is positioned on the outside of cellular membranes. Once activated by the various provocative stimuli, TNF-α leaves the membrane and “docks” on receptors at distant sites to promote an inflammatory reaction.
Regulation of TNF-α is complex and, like many of the inflammatory players,
it is a double-agent. At times it can be a beneficial anti-inflammatory agent that helps to destroy tumours and improves healing of damaged tissues, however, at other times acts as an agent provocateur causing damage itself !
In many cases NF-κB will activate TNF-α, however, at other times the reverse can happen, and through a positive feedback loop TNF-α can further activate NF-κB! TNF-α also acts to activate specific downstream inflammatory products like adhesion molecules. These adhesion molecules are akin to the cholesterol plaque that builds up in blood vessels, and they
NeurodegenerativeDiseases
Parkinson’s, Alzheimer’s, Multiple Sclerosis,
Epilepsy
Heart Disease Atherosclerosis, High
Cholesterol, Heart Attack
Lung DiseasesBronchitis, Cystic Fibrosis
Infectious Diseases Malaria, Measles, Small
Pox, Fevers
Bone or MuscleDisorders
Osteoporosis, musclesprains or dysfunction
Skin Diseases Psoriasis, Eczema,
Wounds, Scleroderma
Liver Diseases Alcohol induced,Cirrhosis, Fibrosis
Endocrine DisordersHypothyroidism, Diabetes
Other Diseases Ulcers, Allergy,
Gall Stones, Asthma, IBD,
Arthritis, Fatigue,Depression
Diseases Linked to
In�ammation
Cancer Breast, Colorectal, Prostate, Stomach,
Lung, Skin, MyelomaKidney etc
Figure 10. Diseases Associated with Inflammation (adapted from Aggarwal and Harikumar, 2009)
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cause damage to the delicate endothelial cells that line the blood vessels and which are vital for the health of the vessels. The ensuing dysfunction of the endothelial cells is one of the major causes of cardiovascular problems.
In other cases TNF-α activates proteolytic enzymes like matrix metalloproteins (MMP’s), which is one of the main mechanisms that tumours use to spread to distant sites. Tumours can use enzymes like MMP’s to eat away the surrounding tissue, allowing them to spread into these areas.
Free Radicals – ROS and RNSThere is a constant battle between the forces of good and evil within the body and in every cell. Biochemists refer to these competing forces as antioxidants and oxidants or pro-oxidants (See Figure 11).
Oxidants are a motley group of reactive oxygen species (ROS) including superoxide anion O2-, hydrogen peroxide H2O2, hydroxyl radical OH- as well as nitrogen species collectively termed reactive nitrogen species (RNS) including 4-hydroxynonenal and various other reactive aldehydes. These molecules or “free radicals” cause much damage to proteins, membranes, DNA and other targets. Certain chemicals or molecules (like cytokines) promote the production of free radicals, and therefore they can be referred to as “pro-oxidants”.
Antioxidants are a collection of protective agents that can be produced by the body or derived from the diet. These include glutathione, catalase, superoxide dismutase as well as vitamins C, D and E to name a few. The net effect of all of these antioxidants is to act as scavengers of oxygen and nitrogen free radicals.
When oxidative stress occurs as a result of exposure to allergens, radiation or toxic chemicals for example, certain defensive cells like mast cells and white blood cells (leukocytes) are quickly recruited to the site of damage which leads to a “respiratory burst” releasing both ROS and RNS into the area. In the
short term ROS and RNS are beneficial and have the effect of neutralizing the offending stimuli and causing acute inflammation. If however, the stressors persist, the continued production of these free radicals begins to cause damage to the healthy tissue. A therapeutic strategy involves neutralizing both ROS and RNS after the initial acute inflammatory process.
COX EnzymesCyclooxygenase is a family of enzymes that work on arachidonic acid, which is a component of the cell membrane. There are two major types of COX enzymes, referred to as COX-1 and
COX-2. The former is a housekeeping enzyme that works on maintaining homeostasis or status-quo of the cells. It is an essential enzyme without which cells would be unable to maintain a healthy state. COX-2, on the other hand, is an enzyme that is induced by many of the factors responsible for inflammation: stress, UV light, toxins etc. COX-2 generates a series of products called prostaglandins (specifically PGE2) that are highly inflammatory.
Several pharmaceutical drugs target COX-2 without affecting COX-1; these are called COX-2 selective drugs. Celebrex® and Vioxx® are examples
Cytokines
Growth Factors
Chemotherapy
Radiation
Pro - oxidants Anti - oxidants
SOD
Catalase
Glutathione
Heme Oxygenase
Peroxidase
Figure 11. Under normal conditions, antioxidants outbalance pro-oxidants, but under oxidative conditions, pro-oxidants prevail over antioxidants, which can lead to many inflammatory diseases, including cancer (from Reuter et al., 2010)
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of this type of anti-inflammatory pharmaceutical. Unfortunately, some of these drugs can cause harmful side-effects like kidney, liver and gastrointestinal damage, and as result they have had to be withdrawn from the market.
Natural Anti-inflammatory AgentsWith so many factors at work, how does one put out all of these inflammatory fires within? Although this is a huge challenge, the numerous pathways allow an opportunity to tackle a multitude of mechanisms simultaneously. Unlike pharmaceuticals that only address one specific pathway, like the classic silver bullet mechanism of action of COX-inhibitors, natural products tend to have much more widespread activity.
Nature is full of anti-inflammatory agents that target many of the pathways associated with inflammation. In fact, unlike pharmaceuticals that have a single target, natural products often have multiple mechanisms. Because we do not yet know which pathways are most critical, this multi-targeted approach to inflammation makes more sense, at least for now since single-targeted therapy has shown little promise. Moreover, an added advantage is that multi-targeted natural products are generally safer since a lower dose is required than for pharmaceuticals.
Boswellia serrataThe herb Boswellia serrata or Indian frankincense has been used in Ayurveda for thousands of years for a multitude of diseases. The empirical evidence
for its anti-inflammatory benefits is strong. More recently, researchers have conducted animal and human studies to verify these anti-inflammatory effects, with several human studies showing very positive results for Boswellia’s anti-inflammatory benefits. An incredibly important aspect of Boswellia is that it does not have a significant immediate effect on inflammation. One study found that while Boswellia showed no significant effect on inflammation in the first month of use, from the second month onward, symptoms were reduced to the same degree as with powerful COX-2 inhibitor pharmaceuticals. All of this was without the side effects associated with COX-2 inhibitors, and, amazingly, the reduction of inflammation in those taking Boswellia was maintained even
Boswellia serrata
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Poor bioavailability is a problem that has plagued many natural supplements over the years. Simply put, bioavailability is the percentage of an ingested ingredient that makes it into your bloodstream, where it can exert a physiological effect. For example, something like curcumin, the active medicinal antioxidant found in turmeric root, has incredibly poor bioavailability; up to 8 grams of pure curcumin can be consumed without gaining ANY detectable levels in the blood.
Because of these bioavailability issues, many ingredients that have shown incredibly promising results in early in vitro studies end up having their benefits significantly reduced or even completely eliminated when the ingredient is taken by humans! This has led scientists to look into the causes of poor bioavailability and also to develop a variety of technologies and strategies that can be used to help enhance the bioavailability of molecules, allowing their benefits to be better harnessed in medications and natural supplements.There are several factors that can cause a substance to be poorly bioavailable:
1. Poor solubility – Many medicinal herb extracts, vitamins and cofactors are what scientists call ‘hydrophobic’, meaning they do not dissolve in water. Much of digestion is based on solubility in water, so many of these end up passing straight through the GI system with little medicinal effect.2. Low stability – Many molecules have low stability in the digestive system. The process of digestion, combining the low pH of the stomach and the higher pH of the intestines, both full of powerful enzymes, break down many molecules that could be beneficial.3. Absorption – If a molecule survives the harsh conditions of the digestive tract and is successfully solubilized by the body, it still needs to be absorbed. This is more difficult than one might think, because the body is very selective, especially when it is something outside of the normal regime of carbohydrates, proteins and fats that the GI system is designed to absorb.4. Metabolism – Poorly bioavailable molecules and extracts are also often degraded by the body, because they are recognized as ‘foreign’, even if they have helpful medicinal properties. This system is highly important, because, while it may frustrate us by causing low bioavailability of supplements that we want to absorb, it also results in the detoxification of molecules that are dangerous.
How can Bioavailability be increased?There are many ways to get around the bioavailability problem, by improving each of the above limiting factors.
Many approaches aim to increase all of these factors, but the real question is, is this wise? Tests on the ingredients in supplements have shown that most can be safely taken at higher doses, which indicates that increasing bioavailability is safe, but is that the only concern? One very common method to increase bioavailability is the inclusion of piperine, a component of black pepper extract. This molecule inhibits the degradation of all foreign molecules. This works very well to increase bioavailability, but has the unintended effect of increasing the amounts of toxins, carcinogens and chemicals retained by the body.
If altering the metabolism of a compound can have negative effects, are there ways to safely increase bioavailability? Definitely. Three of the best ways to increase bioavailability are by improving the solubility, stability and absorption of compounds. Unlike the overly complicated nano-technology used by the pharmaceutical and biotechnology industries, like nano-tubes or other structures, the nano-technology used by the food industry makes use of particle size reduction and various methods to prevent particle clumping. The latter technology is safe and uses ingredients that are safe for use in foods, and it is a strategy that can also be safely and effectively applied to natural health supplements.
What’s the Deal with Bioavailability?
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after patients stopped taking it for a month! A large family of compounds called saponins, and in particular the boswellic acids (BA), have been confirmed as the principal active compounds in this plant. Boswellic acids likely have the most powerful anti-inflammatory effect of all natural products!
It is a common theme that virtually all natural anti-inflammatory ingredients also have an anti-cancer effect. Recall earlier in this issue of Advances we discussed that the German pathologist Virchow made a unique observation that the site of inflammation was often accompanied by cancers at the same
site. Boswellia has been shown to exert anti-cancer effects in-vitro and in animal studies, where it has been shown to reduce both tumour burden and frequency.
In terms of its effects on inflammation in humans, a recent German clinical study showed that inflammation of the brain could be significantly reduced by bioavailable Boswellia extracts which prevented edema, one of the hallmark signs of inflammation. Furthermore, Boswellia has been shown in clinical trials to be more effective than conventional NSAID’s, like ibuprofen, for the treatment of symptoms associated with
osteoarthritis. Moreover, Boswellia extract showed fewer gastrointestinal and kidney side effects than ibuprofen.
Boswellia’s anti-inflammatory action has also resulted in several human trials looking at its potential use in the treatment of inflammatory conditions of the bowel including ulcerative colitis and Crohn’s disease. So far, the results of have been mixed, with some reporting good results and others reporting no effect. One possible reason for this discrepancy is that Boswellia, like many natural products, has a huge bioavailability issue (see Note: What’s the Deal with Bioavailability?). It is conceivable that studies that did not report any effect could have used products that were poorly bioavailable. Food science nano-technology is a safe and effective way of improving the
It is a common theme that virtually all natural anti-inflammatory ingredients also have an anti-cancer effect
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bioavailability of many products like Boswellia.
Finally, Boswellia has been shown to exert a powerful protective effect on the stomach. Boswellia extracts have been shown to prevent or reduce gastric ulcers, yet another action that can be linked to its anti-inflammatory effects.
CurcuminCurcumin is one of the three active components called curcuminoids that are present in turmeric root, a spice widely used by many cultures for culinary, colouring and healing purposes. Curcumin accounts for approximately two thirds of all curcuminoids in the root, with the other two (demethoxycurcumin and bisdemethoxycurcumin) making up the remaining third. In Ayurveda and the traditional Chinese system of medicine, curcumin has been used for a wide range of conditions including, fever, liver and gall bladder ailments, diabetes, heart conditions, gastric problems, skin conditions, infections, diarrhea, memory, cancers and many more.
Curcumin is possibly the most widely researched natural product available, with thousands of in vitro mechanistic and animal studies to back up its effects. More recently, further support for the
benefits of this spice has come from a large number of studies in humans, with several dozen human studies being conducted using curcumin every year! The results of this immense
body of research have repeatedly confirmed that curcumin possesses not only powerful anti- inflammatory properties, but also antioxidant, anticancer and neuroprotective effects.
•Potently reduces NF-κB by both preventing the activation of PKs so the inhibitor IKK remains active and keeps NF-κB in check and by directly breaking down excess NF-κB.
•Inhibits other inflammatory mediators like TNF-α, the various interleukins and others.
•Benefits Alzheimer’s disease by reducing the formation and aggregation of amyloid beta peptide (Aβ) and preventing formation of neurofibrillary tangles (NFT).
•In the central nervous system, curcumin stimulates phagocytes so that Aβ is rapidly cleared. This effect is enhanced in the presence of vitamin D.
•Stimulates the proliferation of nerve cells.•Reduces the COX-2 enzyme selectively without
significantly affecting the housekeeping enzyme COX-
1, all without the gastric, kidney and cardiovascular side effects of pharmaceutical NSAID’s and COX-2 inhibitors.
•Chelates heavy metals like copper and iron which are known to cause inflammation via enzymatic reactions that produce free radicals.
•Stimulates the body’s own defensive enzymes like glutathione, catalase, superoxide dismutase and others.
•Directly quenches both oxygen and nitrogen free radicals, which are primary sources of inflammation.
•Limits arachidonic acid release from cellular membranes by inhibiting an enzyme called phospholipase A2. As a result, there is less substrate for COX and LOX enzymes to work on, reducing the production of inflammatory molecules.
Curcumin
The key anti-inflammatory actions of curcumin
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As an anti-inflammatory molecule, curcumin significantly reduces a huge number of inflammatory biomarkers, especially the very important NF-κB.
Bharat Aggarwal at Texas A&M University is a world leader in curcumin and inflammation research. Aggarwal has published hundreds of reviews and original research on this fascinating molecule. Aggarwal is a strong proponent of reduction of NF-κB as a means of reducing the effects of chronic inflammation. Overall, his research has concluded that curcumin’s anti-inflammatory properties are
wide ranging, and include a variety of different mechanisms and targets.
It must be pointed out that curcumin has a huge bioavailability issue. Bioavailability refers to the amount of the active compound that reaches the target site. In the case of curcumin, for example, this would be the amount that reaches the nerve cells in the brain or the joints, liver, kidneys or other target tissues. There are many possible reasons for the poor bioavailability of curcumin. For example, the curcumin molecule isn’t very soluble in the digestive tract,
it is unstable due to pH conditions, it is too big to be easily absorbed by the gastrointestinal tract and finally, it is rapidly broken down by the detoxification enzymes that protect the body. Numerous approaches have been utilized to improve the bioavailability of curcumin, for example, using smaller particles of curcumin can have a significant effect on improving the bioavailability of this beneficial molecule. For more information about improving bioavailability, see the Note in this article: “What’s the Deal with Bioavailability?”
Green Tea PolyphenolsGreen tea is another widely studied natural product. The active components in green tea are a group of polyphenols called catechins, including epigallocatechin gallate (EGCG). These catechins are typically found in unfermented green tea leaves. Fermented black tea leaves generally have little or no catechin content, but instead are high in theaflavins, which have different physiological actions.
Catechins and other polyphenols have been shown to act at multiple sites in the inflammatory cascade. For example, they act to quench oxygen and nitrogen free radicals, inhibit COX-2 enzymes, and prevent the IKK from being inactivated, thus preventing NF-κB from becoming activated. Green tea also prevents TNF and other signaling molecules from being activated. More recent research suggests that green tea polyphenols act through over two dozen different mechanisms, much like the curcumin molecule. Clinical research also suggests that EGCG has a powerful anti-cancer effect, especially for breast, prostate, skin and colon cancers. These anti-cancer effects could be closely linked to EGCG’s role in inhibiting inflammation.
Omega 3 fatty acids rich in EPA and DHAEicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two of the many omega-3 fatty acids found in nature, and especially in
Camellia sinensis
Recent research suggests that green tea polyphenols act through over two dozen different mechanisms
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fatty fish like salmon and anchovies. Plant sources of omega-3 fatty acids are also becoming more common. For example, algae are an excellent source of DHA, and nowadays algae can be commercially harvested under controlled conditions. Most other plant sources contain predominately other omega-3 fatty acids, like alpha linolenic acid, which are not converted very efficiently into EPA/DHA. New research is starting to look at the potential to extract EPA from algae sources as well.
Many of us have heard that omega-3 fatty acids are important for good health, and part of this health benefit comes from the role they play in reducing inflammation. Arachidonic acid (AA) is abundantly present in the membranes of cells. When a cell is exposed to an inflammatory stimulus, an enzyme called phospholipase is released that causes AA to leave the membrane and move into the interior of the cell. Inside the cell, two sets of enzymes called COX and LOX utilize AA breaking it down to two highly inflammatory molecules called prostaglandin E2 (PGE2) and leukotriene B4 (LTB4).
EPA and DHA are important because they can actually take the place of AA in cell membranes. In individuals with a high intake of EPA/DHA the cell membranes contain more EPA and DHA and less AA. As a result, when provoked by inflammatory signals, EPA or DHA leaves the cell membrane instead of AA. COX and LOX enzymes then act on these fatty acids, but instead of forming the highly inflammatory PGE2 or LTB4 that come from AA, they form fairly innocuous and non-inflammatory molecules.
Additionally, both EPA and DHA have been shown to possess potent anti-inflammatory properties in their own right. For example, in animals fed DHA and then provoked with an inflammatory stimulus, the amount of resulting inflammation is considerably reduced. Similarly, in humans a high intake of EPA and/or DHA significantly reduces key inflammatory
markers like TNF and NF-κB. Furthermore, omega-3 fatty acid intake has been shown to reduce the intake of NSAIDs by arthritis patients. DHA intake is also associated with a reduced risk of Alzheimer’s disease. For example, research has shown that restricting DHA in laboratory animals increases their risk of Alzheimer’s disease while the addition of DHA to the diet reduces the pathology of the disease. Similarly, EPA has been shown to powerfully reduce inflammation of the blood vessels.
Not only do omega-3 fatty acids act as anti-inflammatory molecules, they also act directly as antioxidants by quenching free radicals of oxygen and nitrogen species and indirectly by
boosting the body’s own antioxidant defense system through the stimulation of antioxidant enzymes like catalase, superoxide dismutase and glutathione peroxidase.
AshwagandhaAshwagandha is another Ayurvedic herb that has been used for centuries. Often but erroneously called the Indian ginseng, ashwagandha is a powerful anti-inflammatory agent with a strong action against NF-κB. Ashwagandha has been shown to accelerate the breakdown of NF-κB, which is different than other natural agents that act to prevent its activation in the first place. As such, ashwagandha provides a unique alternative pathway
30 Advances
for reducing NF-κB levels, and thus inflammation.
Unfortunately, while ashwagandha has excellent supporting empirical data, there are few well controlled human studies that have examined its anti-inflammatory action. Nevertheless, animal studies confirm that ashwagandha, and its active components the sitoindosides, are powerful anti-inflammatory agents.
In addition to this, ashwagandha has been shown to have other physiological effects, including anti-cancer actions, anxiety reducing properties and a powerful immune system stimulating effect. It can therefore be speculated that since ashwagandha acts to stimulate the immune system (particularly the action of macrophages), its use in conjunction with more traditional and well known anti-inflammatory herbs like curcumin and Boswellia could result in the exertion of a more powerful anti-inflammatory effect.
Putting it all TogetherIn the end, there are a wide variety of powerful natural herbs and molecules that have shown very promising results for the reduction and prevention of inflammation. The advantage of these natural anti-inflammatory agents is that they act through a variety of mechanisms
and influence a wide range of targets and molecules involved in the body’s inflammatory response. These natural agents are safe and effective, and can be used in combination to help control and prevent chronic inflammation throughout the body. By preventing and treating chronic inflammation, it
may be possible to reduce the risk and progression of many serious diseases that have been linked to inflammation. Finally, through the use of various novel techniques to improve bioavailability, the full extent of the benefits of these natural anti-inflammatory agents can be realized.
Ashwagandha
Key ReferencesAggarwal B et al. Role of resveratrol in prevention and therapy of cancer: preclinical and clinical studies. 2004. Anticancer Res. 24: 2783-840.Aggarwal B et al. From traditional Ayurvedic medicine to modern medicine: identification of therapeutic targets for suppression of inflammation and cancer. Expert Opin Ther Targets. 2006. 10: 87-118.Aggarwal B et al. Inflammation and Cancer: How hot is the link? Biochem Pharmacol. 2006. 72: 1605-1621.Aggarwal B and Harikumar K. Potential therapeutic effects of curcumin, the anti-inflammatory agent, against neurodegenerative, cardiovascular, pulmonary, metabolic, autoimmune and neoplastic diseases. Int J Biochem Cell Biology. 2009. 41: 40–59Fox JG and Wang TC. Inflammation, atrophy, and gastric cancer. J Clin Invest. 2007. 117:60-69Frautschy S and Cole B. Why pleiotropic interventions are needed for Alzheimer ’s disease. Mol Neurobiol. 2010. 41: 392-409Karin M and Lin A. NF-kappa B at the crossroads of life and death. Nat Immunol. 2002. 3: 221-227Libby P. Atherosclerosis and Inflammation. Nature. 2002; 420: 19/26.Liu H et al. Inflammation: A key event in Cancer development. Mol Cancer Res. 2006: 4(4)Madea S and Omata M. Inflammation: A key role in Cancer. Cancer Sci 2008; 99: 836–842Nathan C. Points of Control in Inflammation. Nature. 2002. 420: 846-852Ralhan R et al. Nuclear Factor-Kappa B links carcinogenesis and chemopreventive agents. Front Biosciences. 2009. S1: 45-60.Rodger K and Crabtree JF. Helicobacter pylori and gastric inflammation. Br Med Bull. 1998. 54: 139-150
Advances 31
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