From Bench To markeTProBioTics
Proceedings of the symPosium Presented by
Program made possible by an unrestricted educational grant provided by the dannon company, inc. and award 1 r13 Ai088836 – 01 from the national institute of Allergy and infectious diseases.
Probiotics are live microorganisms, which, when administered in adequate amounts confer a health benefi t on the host. In the U.S., they are present in conventional foods and dietary supplements, but not in human drugs. Th ey represent a rapidly expanding fi eld, both scientifi cally and commercially. In 2005, there were 40 probiotic products on the market in the U.S. By 2007, there were 300. Over the past 20 years, this fi eld has progressed from one characterized by unsubstantiated hypotheses and largely untested products to one that has gained the attention of top-notch scientists and clinical researchers publishing in the world’s best scientifi c journals. But the fi eld still has far to go.
In June, 2010, academic and industry scientists and government regulators gathered in New York City for the symposium Probiotics: From Bench To Market, jointly presented by Th e New York Academy of Sciences and Th e Dannon Company, Inc., to highlight progress in identifying mechanisms and measuring the extent of probiotic functionality in the gastrointestinal, nervous, and immune systems. Presentations by industry scientists described novel ways that commercial probiotic products are being studied in order to determine their health eff ects. Academic scientists addressed challenges in the conduct of probiotic clinical research, and U.S. regulators described appropriate approaches to conducting probiotic research.
Th e science behind probiotics and their impact on human health is still emerging. But the science may be the easy part. Current U.S. regulations do not allow probiotic foods to be marketed for the multitude of health benefi ts suggested by emerging science because regulators argue that the legal defi nition of “food” excludes its use in preventing, curing, treating or mitigating acute disease or providing dietary support to help people cope with adverse health conditions. Your doctor may tell you to “eat yogurt” when prescribing an antibiotic, but such a suggestion would make that yogurt an illegal drug in the eyes of regulators if made in advertising or labeling.
During this symposium, the probiotic research, industry and regulatory communities engaged in an open conversation about challenges aff ecting the interface of research, product marketing and regulatory oversight. Figuring out a path to encourage strong probiotic research and responsible product marketing while satisfying regulators that food law is upheld and that consumers are protected is a high priority. I hope our discussions in New York provide the necessary impetus for changes in the path of probiotics from the bench to market.
Sincerely,
Mary Ellen Sanders, PhD
mary ellen sanders, Phddairy and food culture technologiesexecutive directorInternational Scientifi c Association for Probiotics and Prebiotics
Welcome & Introduction
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Contents
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Highlights from the SymposiumProbiotics: From Bench To MarketTh e New York Academy of Sciences New York, NY | June 11, 2010
Reported by Megan Stephan, PhD:
Impact of Probiotics on the Central Nervous System 4
Understanding and Altering the Intestinal Microbiota 5
Models for StudyingEffi cacy in Probiotics 6
Major RegulatoryChallenges 7
Probiotic Foods:Developing and Implementing Quality Clinical Trials 8
Th erapeutic Probiotics: Designing and Implementing Quality Clinical Trials 9
In-Brief: Innovations inProbiotics Research 10
Suggested Reading 11
Resources & Frequently Asked Questions 12
Welcome & Introduction fromMary Ellen Sanders, PhD 2
Impact of Probiotics on the Central Nervous System
emeran mayer, mdProfessor, departments of medicine, Physiology, Psychiatry & biobehavioral sciences, at the david geffen school of medicine, university of california, Los Angeles; director, ucLA center for neurovisceral sciences & Women’s health (cns/Wh), ucLA division of digestive diseases; chair, university of california Los Angeles, collaborative centers for integrative medicine
Most people are well aware of the fact that the central nervous system (CNS) and the gut are intimately connected. Many common neuro-physiological states, including stress, pain, and depression, can have intense eff ects on gastroin-testional (GI) function, for example, the churning stomach and diarrhea associated with stress or fear, or the loss of appetite that stems from grief or depression. Th e reverse is also true: the physi-ological state of the gut can have eff ects on mood, behavior, and the perception of pain. Recent stud-ies have elucidated the role of the gut microbiota in this important ongoing conversation between gut and brain, known as the gut-brain axis (GBA).Please see Figure 1 for some examples of interac-tions along the GBA.Stress has multiple eff ects on the gut, including in-creased gastric acid production and increased GI motility, which would aff ect the gut environment and thus the growth and physiology of bacteria living there. Stress has also been shown to cause changes in the composition of gut microbiota in studies of infant rats and monkeys subjected to premature separation from their mothers. Cer-tain probiotics have been shown to reverse these changes and to normalize altered stress responses found in animals subjected to such early life stress-es. Stress also causes changes in neurotransmitter levels, which could aff ect not only the gut itself but also the bacteria therein. It has long been known that certain neurotransmitters can have direct ef-fects on bacterial physiology. Th e neurotransmit-ter norepinephrine, for example, has been shown to promote virulence in highly pathogenic strains of Escherichia coli and in another intestinal patho-gen Campylobacter jejuni.Studies have also implicated the gut microbiota in modulating the sensation of pain. Treatment with antibiotics can lead to pain hypersensitivity (hy-peralgesia) in the intestine, and it has been shown that this hypersensitivity can be reduced with the use of probiotics.Certain probiotics have also been shown to reduce pain sensitivity in animal models of pain such as acute infl ammatory hyperalgesia. It is hypoth-esized that this antihyperalgesic eff ect of probi-otics is related to the engagement of endogenous opioid systems. At the same time, however, studies in germ-free mice have shown that the presence of the gut microbiota is necessary for the devel-
opment of a hyperalgesic state, perhaps because in the normal gut, the presence of bacteria stimulates the production of interleukin-10, a cytokine in-volved in suppressing the infl ammatory response. Further research will be needed to reconcile these somewhat contradictory results.A number of other research lines suggest that in-testinal microbes have important eff ects on psy-chological states. Animal studies provide evidence that the state of the gut can aff ect both mood and behavior. In rats, initial intestinal infection with Toxoplasma gondii, followed by localization to the brain, has been reported to have direct eff ects on performance in behavioral tests. A recent study of the neurobiological and immunomodulatory eff ects of a probiotic strain of Bifi dobacterium in-fantis in rats suggests that this probiotic could have antidepressant eff ects in this model. In mice, in-fection with the bacterium Citrobacter rodentium has been shown to induce anxiety-like behavior.In humans, epidemiologic studies show that nega-tive emotions are oft en associated with the devel-opment of acute GI infections, and conversely, chronic GI infl ammation has multiple eff ects on mood, including symptoms of depression and fa-
tigue. Risk factors for the development of irritable bowel syndrome include adverse life events, de-pression, and neuroticism. Th ese multiple lines of evidence illustrate the in-timate nature of the connections between gut, brain, and gut microbiota, and suggest that the use of probiotics might someday go well beyond maintenance of intestinal health alone. Further in-vestigation in both animals and humans will allow greater delineation of these connections, perhaps one day allowing the use of probiotics as clinical agents to treat or assist in the management of se-rious psychological conditions such as depression or post-traumatic stress disorder.
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Dr. Mayer has a long-standing interest in clinical and neurobiological aspects of brain-gut interactions. He has made semi-nal contributions to the characterization of physiologic alterations in patients with functional disorders, particularly in the ar-eas of visceral pain, stress-induced visceral hyperalgesia and altered brain responses.
Figure 1. Integration of the microbiota into the gut-brain axis(Modifi ed with permission from Collins S, Bercik P. 2009. Gastroenterology 136: 203-214.)
Understanding and Altering the Intestinal Microbiota
Justin L. sonnenburg, PhdAssistant Professor, microbiology & immunologystanford university
One of the diffi culties with attempting to manipu-late the gut microbiota is the current scarcity of knowledge regarding exactly how they function. In order to manipulate the gut microbiota for clinical purposes, it will be important to understand, in a systemic way, how these microbes adjust to chang-es in host diet, how they adapt to the introduction of new species or to the loss of species, and what role host genetics play in the ecosystem’s com-position and function. Th e Human Microbiome Project (http://commonfund.nih.gov/hmp) has generated large amounts of important sequence data that identifi es the many bacterial species and genes involved; however, knowledge of how this complex ecosystem actually functions has lagged signifi cantly.Th e development of simplifi ed model systems of the gut microbiota can potentially allow such questions to be addressed more readily, and these models could facilitate investigation of the multi-faceted roles microbiota occupy. One particu-larly important function of the gut microbiota is metabolism of carbohydrates, which serve as one of the primary nutrient sources for this commu-nity. Due to the density of microbes within the complex intestinal ecosystem, numerous bacte-rial species compete to break down and utilize the carbohydrates that we ingest, particularly the more complex plant carbohydrates that we are poorly equipped to metabolize on our own.In recent studies in Dr. Sonnenburg’s laboratory, germ-free mice were colonized with simplifi ed microbial communities to investigate how the genetics of both host and microbes aff ects meta-bolic function. Although 10 bacterial divisions and thousands of species are represented in the human and mouse gut microbiota, more than 90% of the microorganisms belong to the Bacteroidetes and Firmicutes divisions of bacteria, so one way to re-duce complexity is by working just with represen-tatives of these two groups.Initial experiments looked at the genetics and me-tabolism of a single species in this model system, Bacteroides thetaiotaomicron (B. theta). Th is or-ganism is a prominent member of the human mi-crobiota that has the advantage of being easily cul-tivated outside the body. Th e genome of B. theta, largely geared toward carbohydrate metabolism, includes at least 64 enzymes that are devoted spe-cifi cally to the digestion of plant polysaccharides that humans cannot digest and over 260 carbohy-drate-degrading enzymes in total, out of a total ge-nome of 4779 genes. When compared to the many fewer carbohydrate-degrading enzymes in humans (we have fewer than 100) despite our much larger genomes of 25,000 genes, this microbial resident of
the human body evidently possesses many novel and important metabolic capabilities.Functional genomics techniques were used to ex-amine how the expression of these carbohydrate-degrading genes changes when diff erent foods are introduced into the mouse host’s diet. Addition of another species, Bifi dobacterium longum, to the system, allowed study of this organism’s gene ex-pression, as well, providing valuable information on how these two species compete for and adapt to the ecological niches that are available under dif-ferent conditions. Studies are also examining the eff ects of inulin, a dietary polysaccharide from the fructan family that is found in many plants. Inulin is present in many processed foods and is widely used as a prebiotic—a non-digestible food ingredient that stimulates the growth and/or activity of bacteria in the diges-tive system that are benefi cial to the health of the body. Inulin has been shown to alter the composi-tion of the human gut microbiota, in some cases by expanding the population of Bifi dobacterium spe-cies. In Bacteroides, inulin induces the expression of a series of enzymes that are needed for inulin’s metabolism. It may be possible to use the gene se-
quences that encode these enzymes as biomarkers to detect specifi c diet-induced changes in micro-biota composition in humans as well.Th ese studies will help to elucidate the mechanisms of pre- and probiotics, and to identify whether changes in gut microbiota are the cause or the result of a given disease state. Th e insights gained should someday allow more precise manipulation of the human gut microbiota, which will be par-ticularly important once a better understanding of the microbial ecosystem’s optimal content has been achieved.
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Dr. Sonnenburg’s research examines the basic principles that govern interactions within the intestinal microbiota and between the micro-biota and the host. To pursue these aims, his laboratory colonizes germ-free (gnotobiotic) mice with simplifi ed, model microbial com-munities, applies systems approaches (e.g. functional genomics), and uses genetic tools to gain mechanistic insight into emergent prop-erties of the host-microbial super-organism.
Figure 2. B. thetaiotaomicron (B. theta) and B. longum bacteria, when occupying the same cecal space (co-colonized), show di� erential expression of glycoside hydrolase and polysaccharide lyase genes.Results indicate B. theta expands expression of glycoside hydrolases in co-colonization with B. longum—a greater variety of genes associated with digestion of dietary plant or host mucus polysaccharides show increased expression in co-colonization compared to mono-association. (Figure adapted from Sonnenburg JL et al, PLoS Biology, 2006)
Models for Studying Effi cacy in Probiotics
As in many areas of clinical research, probiotics studies will progress more quickly and cost-ef-fectively with the development of in vitro mod-el systems that can be used to test new ideas before they are tried in animals or humans. Such models can be particularly challenging to develop for pre- and probiotics because the gut and the gut microbiota are such highly com-plex systems. Multiple research groups have taken on the challenge of developing such models, ranging from fairly simple, single-vessel fermentation setups to complicated, multi-stage fermenta-tion systems that are intended to replicate the sequence of digestive compartments formed by all or part of the human gut. In a single-vessel batch fermentor, pH and nutrient concentra-tions are controlled to allow relatively simple studies of the growth and physiology of mixed fecal cultures or other inocula. Micro-fermen-tors that use very small volumes have also been developed, which are particularly useful when it is necessary to conserve study materials.In more complex, multi-compartmental fer-mentation systems, computers are used to con-trol conditions at each stage so that each acts as a representation of a specifi c digestive com-partment, forming a complex model of all or part of the gut lumen. Th ese more complex sys-tems are useful for studying both the eff ects of pre- and probiotics and particularly how they persist with time. Such systems make it easier to model complex interactions between gut compartments and their resident microbiota, and they can also be used to study the eff ects of experimental compounds that are in develop-ment as clinical therapies. One such system consists of a series of culture vessels whose contents replicate the sequence of volumes and pHs found in diff erent areas of the human large intestine. Th e properties of each vessel in this continuous system were validated against the gut contents of victims of sudden death to provide a more accurate model sys-tem. Th e system is inoculated with mixed fecal bacteria from human volunteers and allowed to run continuously to set up an in vitro model of this area of the gut. Pre- or probiotics are then added to the system to study their eff ects and
their persistence in an environment that is very similar to the human gut.Th is system has been used to investigate the functions of a prebiotic known as GOS, a mix-ture of galactooligosaccharides. GOS intake has been shown to reduce symptoms in patients with irritable bowel syndrome and travelers’ diarrhea and to modulate levels of pro- and an-ti-infl ammatory cytokines in elderly individu-als. Addition of GOS to the model system has a considerable eff ect on the distribution of bacte-rial species, including a large increase in Bifi do-bacterium species. Th is increase has also been observed in healthy human volunteers and in individuals with irritable bowel syndrome who ingest GOS. Th e in vitro system thus appears to replicate the human system adequately. Th ese experiments will help to elucidate both the mechanisms by which GOS raises Bifi dobacte-rium content and how such an increase might alleviate irritable bowel symptoms. Ultimately, studies of pre- and probiotics must be done in humans before it will be possible to make health- or disease-related claims for these agents, but the information provided by in vitromodels will provide valuable guidance on what might or might not be fruitful when tried in humans. In addition, these models will allow the elucidation of the mechanisms of pre- and probiotics, important information that can be diffi cult to gain with studies using animals and humans.
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Figure 3. A multi-vessel fermentation sys-tem used to model the sequence of digestive compartments (Photo courtesy of Dr. Gibson)
Dr. Gibson’s team studies pre- and probi-otic mechanisms, molecular genotypes of gut bacteria, metabolomics of the gut, and colonic gas metabolism. Th e group also investigates the relationship between diet and cancer, the role of bacteria in lipid reduction, and the production of hydro-gen sulfi de as well as such phenomena as obesity, autism, ulcerative colitis, irritable bowel syndrome, colorectal cancer, and co-lonic homeostasis in companion animals, farm animals, and human subjects. Th is research involves in vitro gut models and controlled volunteer trials.
glenn gibson, PhdProfessor of food microbial sciencesuniversity of reading, united Kingdom
Major Regulatory Challenges
cary P. frye, bsVice President, regulatory Affairsinternational dairy foods Association
Depending on their intended uses, probiotics are subject to a wide range of potential types of regulation. Factors that may infl uence how a probiotic product is regulated include formu-lation (pills or capsules), route of administra-tion (oral for foods and supplements), targeted consumers, and food safety considerations if new dietary ingredients are involved. Because of their many forms and uses, probiotics may be regulated as conventional foods, as dietary supplements, or as drugs, and are subject to diff erent labeling and marketing restrictions based on the uses claimed by their manufac-turers. Companies producing probiotics are understandably eager to communicate the health benefi ts of their products to consumers but must be careful to follow these regulations if they are to avoid penalties from the U.S. Food and Drug Administration (FDA).Claims for probiotics could potentially range from structure/function claims (e.g. “helps sup-port the immune system”) to health claims (i.e. that the product reduces the risk of a specifi c disease). A probiotic that is intended for use in diagnosing, curing, mitigating, treating, or pre-venting a human disease is considered a drug. Clinical trials to evaluate probiotics for medical uses require an Investigational New Drug ap-plication (IND) to be submitted to the FDA. Health claims must be based on the FDA’s re-view and approval of a health claim petition or notifi cation of an authoritative statement from a scientifi c body of the U.S. government or the National Academy of Sciences, or the claims must be qualifi ed if the science has not yet reached the level of signifi cant scientifi c agreement. FDA guidance published in 2009 describes the standards of evidence that health claims must meet. In addition, FDA guidance published in 2008 describes what is needed to substantiate structure/function claims for foods, including dietary supplements. Current-ly there are no FDA-recognized health claims for probiotics.Structure/function claims, which focus on the maintenance or support of body structures or functions in healthy individuals rather than disease prevention or treatment, are not sub-ject to FDA approval, but statements made in product labeling must be truthful and not
misleading. Frye shared the examples that the claims: “Helps maintain healthy intestinal fl ora” or “Helps support immune function” are considered structure/function claims, not dis-ease claims, whereas “Helps individuals using antibiotics to maintain normal intestinal fl ora” or “Protective against the development of diar-rhea” would be viewed as unauthorized health claims or drug claims. In all cases, the burden of proof for product labeling rests with the manufacturer to have accurate substantiation supported by competent and reliable scientifi c evidence.Probiotics manufacturers face substantial chal-lenges in navigating these regulatory require-ments. Th ey must have a good working knowl-edge of the regulations involved and word their package labeling so that the claims align with available evidence. Oft en manufacturers them-selves will need to develop, by performing or funding clinical studies, the necessary scientifi c evidence for claims they wish to make. Novel types of claims may also require manufactur-
ers to seek expert counsel or to ask the FDA to provide specifi c guidance on how to substanti-ate them. Th ese rules and regulations are some-times diffi cult to follow but provide needed protection for the consumer.
Ms. Frye represents member companies on product safety, food labeling and standards of identity, ingredient technologies, and nutrition and health issues. She is respon-sible for the technical development and regulatory oversight of nutritional mar-keting programs and processor materials that incorporate breaking medical and nu-tritional research. Furthermore, Ms. Frye chairs the International Dairy Federation Standing Committee on Food Labeling and Terminology.
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Probiotic Foods: Developing & Implementing Quality Clinical Trials
dan merenstein, mdAssistant Professor and director of research Programs,department of family medicine, georgetown university medical center
Many researchers are interested in studying probiotics in foods because of the potential for a higher impact than when they are in-gested alone as supplements. Such studies are necessary because probiotics that are successful as supplements do not necessarily work in the form of a yogurt, cheese or cere-al. Probiotics occupy an unusual position in the FDA approval process because in many cases they are components of foods that have been consumed for centuries without appar-ent ill effects. Some researchers would argue that testing these substances for safety slows down the approval process unnecessarily and wastes money.After conducting a number of randomized trials of probiotics in healthy children, NIH funding was obtained for a study on whether consuming probiotics, in the form of yo-gurt, reduces diarrhea in children who are taking antibiotics. Because this study would investigate the ability to cure or mitigate a disease condition, the NIH center that funded the project, the National Center for Complementary and Alternative Medicine (NCCAM), required that the Center for Bio-logics Evaluation and Research (CBER) at the FDA be asked if an IND (Investigational New Drug) application was required. Probi-otics fall under the definition of biologics, and as such are regulated by CBER rather than by the Center for Drug Evaluation and Research (CDER), which is responsible for evaluating drug compounds. Previous studies of probiotics in healthy chil-dren did not require INDs (Investigational New Drug applications) because, according to the stated aims of the studies, they were intended to support only structure/function claims. Outcomes that were assessed in these studies included the prevention of daycare absences and reduction of parental reports of loose stools. For comparison, another study currently in preparation will compare amoxicillin, prednisolone, and neti-pots for the treatment of sinusitis. This planning grant is supported by the National Institute of Allergy and Infectious Diseases (NIAID), which also required contact with the FDA to
inquire about a potential IND. CDER, un-der the auspices of an investigator-initiated IND, exempted the study from an IND pro-cess because of the long-standing uses of the therapies involved.Submitted in October 2006 and approved in June 2007, the grant application for funding the proposed diarrhea clinical trial was then
required to undergo an IND review process. After multiple rounds of communication, the IND was approved in November 2008. NCCAM issued the grant award in August 2009, more than two years after indicating its intent to award the grant. As part of the process, the FDA required, and NIH funded, an initial safety study of the yogurt with pro-biotics in healthy adults, even though the product was equivalent to one currently on the market as a food and had been ingested by many people. However, this requirement is in keeping with current FDA general rec-ommendations that drugs should be tested in adults before they can be tested for pedi-atric uses.There are several steps that the FDA and NIH could take to reduce the difficulties associ-ated with testing probiotics for drug indica-tions. CBER currently does not grant inves-tigator-initiated INDs as does CDER. Since many probiotics, especially those found in foods, have been consumed widely, it seems that probiotics studies would be likely to gain exemptions if CBER were able to give them. In addition, it will be important for the NIH to fund more patient-oriented clinical trials in this area, in addition to the Phase 1 safety studies and basic science studies of the mi-crobiome and probiotic mechanisms that are currently funded. Such studies would pro-duce more immediate public health benefits by providing evidence of the health effects of probiotics in individuals with disease condi-tions. The U.S. could fall behind consider-ably in probiotics studies if such changes are not made in the near future.
Dr. Merenstein’s research interests include complementary and alternative medicine, sinusitis and probiotics. He approaches all of these interests with primary care in mind. In the last 3 years he has been the principle investigator on 5 diff erent pro-biotic pediatric trials that have enrolled over 1,300 participants.
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Probiotic Foods: Developing & Implementing Quality Clinical Trials Therapeutic Probiotics: Designing & Implementing Quality Trials
Patricia hibberd, md, PhdLecturer on Pediatrics, harvard medical school; chiefdivision of global health, department of Pediatrics,massachusetts general hospital
Although probiotics have been consumed in many cultures and societies, sometimes for centuries, until recently very little work had been done to investigate the eff ects of these organisms on health and disease. Some of the recent history of probiotics research in the U.S. and in the rest of the world can be examined using data available at the public website ClinicalTri-als.gov. From 2005 through 2010, there were 63 ac-tive probiotics trials in the U.S., compared to 84 in Europe, 39 in Asia, and 25 in the rest of the world. In recent years, there has been a trend towards more
trials outside the U.S. and more in healthy individu-als. Studies in the database are primarily intended to provide evidence for the treatment or prevention of diarrhea and other GI conditions, but they also in-clude studies on allergies, respiratory diseases, and conditions related to premature birth. Studies are occurring in all age groups, from children, includ-ing neonates, to the elderly.Unfortunately, in the past many studies of probiot-ics have been of poor quality, including many with problems concerning the underlying biologic ratio-nale, experimental design, safety, and measurement of appropriate clinical outcomes. Th e Cochrane Review, which conducts rigorous analyses of clini-cal evidence, has raised questions about the quality of clinical trials in most areas where probiotics have been tested. One diffi culty in gauging the quality of the evidence is that the Cochrane Review’s analyses aggregated studies on many disparate types of pro-biotics, most likely of necessity since clinical trials are still quite uncommon. It is likely that the eff ects of probiotics are species and even strain specifi c.Dr. Hibberd’s group recently prepared two investi-gator-initiated INDs (Investigational New Drug ap-plications) for two NIH-supported trials on the use of probiotics to prevent infection. One IND eventu-ally had to be withdrawn due to a number of issues, including minimal assistance from a prior manu-facturer. Th e resubmitted IND had strong sup-port from the new manufacturers but was placed on clinical hold when the FDA requested a Phase I study in healthy adults before the original, NIH-funded adult and pediatric study could proceed. In July 2009, aft er revisions to the research design to accommodate the FDA’s request, the hold was lift ed and the Phase I study in healthy adults was able to proceed. Some of these diffi culties could have been avoided by requesting a pre-IND meeting with the FDA to fi nd out what was likely to be required in the IND and by obtaining assurances from the manu-facturers of the products that they would cooperate before embarking on the IND process.As a key funder of clinical studies of probiotics, NC-CAM (the National Center for Complementary and Alternative Medicine) at the National Institutes of Health (NIH) plays a major role in guiding the research agenda and in encouraging collaboration with other organizations to improve the quality and value of the research. Collaborations of impor-tance include those with investigators funded by the NIH-funded Human Microbiome Project and the U.S. Department of Agriculture. Th ese collaborat-
ing investigators have cutting-edge technology that is being used to study the mechanisms of action of probiotics. However, the multiple layers of review and regulatory oversight at the NIH and the FDA have resulted in considerable delays (stretching to several years) before any part of the funded research can proceed. Th ere is also a disconnect between the FDA’s need for the Phase I safety studies to be con-ducted prior to probiotics studies in patients and the process of peer review at NIH. Peer reviewers are looking for cutting-edge science of public health im-portance, and Phase I safety studies do not usually meet those requirements, by defi nition. It is also dif-fi cult for reviewers and many others to understand why Phase I safety studies are needed when there are extremely long histories of probiotics use with-out reported safety concerns. However, the FDA assesses the quality of the manufactured probiotic and the safety and quality of the clinical trials being conducted with the probiotic in the IND process.Since many probiotics studies are plagued by poor design, it is thought that completion of an IND will lead to a higher quality study, since such an appli-cation requires interactions with and advice from experts at the FDA. However, while completing an IND does confers benefi ts, among them, assistance with product quality issues and other valuable guid-ance, it also creates substantial challenges, including the time involved and the need to reconcile FDA guidance with other institutional requirements. In addition, it remains to be seen whether completing an IND improves the credibility of clinical trials of probiotics with health care professionals or the gen-eral public. In the end, the quality of a given study remains the responsibility of the investigator, and the quality of the probiotic product remains the respon-sibility of the manufacturer, whether or not an IND is fi led. High quality research in humans remains the goal, and research quality will ultimately determine whether probiotics are accepted in the mainstream to improve human health and treat diseases.
Dr. Hibberd’s research is focused on Global Health, the prevention and treatment of childhood pneumonia and diarrhea, mecha-nisms of action of probiotics, and their eff ects on prevention and treatment of infections. Th is research involves clinical/translational research methods and the conduction of Phase I/II clinical trials under investigator-initiated INDs.
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Probiotics Inhibit Behavioral Signs of Depression A� er a Myocardial Infarction in a Rat ModelGuy Rousseau, PhDDepartment of PharmacologyUniversité de Montréal (Québec), Canada
Over 20% of patients who suff er a myocardial infarction (MI) develop major depression, which is associated with a 3- to 4-fold increase in subsequent mortality. Th is phenomenon is thought to be related to the release of pro-infl ammatory substances and increased cell death, or apoptosis, in specifi c areas of the brain. Prophylactic intake of a combination of the probiotics, Lactobacillus helveticus R0052 and Bifi dobacterium longum R0175, was found to reduce post-MI apoptosis in rats with experimentally induced MIs, to reduce levels of the infl ammatory cytokine interleukin-1β and signs of depression, and to restore intestinal barrier function.
Study of the Interplay Between Gut Microbiota and Ingested Bene� cial Bacteria in Irritable Bowel Syndrome Subjects with Predominant ConstipationPatrick Veiga, PhDDanone Research, France
Genetic analyses were used to monitor changes in the gut microbiota of individuals with irritable bowel syndrome with constipation. Th ese individuals were monitored aft er they consumed yogurt containing the probiotic Bifi dobacterium lactis DN-173 010.Instead of large global shift s in microbial species, results showed only a few species changed a great deal with ingestion of the probiotic product. Survival of the ingested probiotic strain, as monitored in fecal samples, varied from person to person, which may be related to whether or not individuals with irritable bowel experience relief from symptoms with probiotic ingestion.
Lactobacillus rhamnosus GG Attenuates Interferon-γ and Tumor Necrosis Factor-α–Induced Epithelial DysfunctionKevin A. Donato, HonBScHospital for Sick Children, Toronto, Canada
Pathogenic bacteria like E. coli strain O157:H7 can break down tight junctions between epithelial cells in the mucosal layer of gut, causing watery diarrhea and dangerous fl uid loss. Th e bacterium Lactobacillus rhamnosus GG (LGG) prevents the colonization of pathogenic bacteria and infl uences immune responses in the human gut. Testing in intestinal cell tissue culture shows that LGG attenuates barrier dysfunction, apparently by reducing the attachment of pathogenic bacteria and modulating pro-infl ammatory epithelial cell signaling.
Exacerbation of Dextran Sulfate Sodium (DSS)-Induced Colitis by Localized Delivery of Interferon-β Secreted by Lactobacillus acidophilusHoward A. Young, PhDNational Cancer Institute
Probiotic strains have the potential to be used as delivery systems for therapeutic compounds, including immunomodulatory peptides such as interferons. Previous studies suggested that treatment with interferon β-1α might benefi t patients with ulcerative colitis, while others suggested that the peptide causes ulcerative colitis when used to treat patients with multiple sclerosis or hepatitis. In accordance with the latter results, mice inoculated with a probiotic Lactobacillus acidophilus strain expressing interferon β-1α were rendered more susceptible to experimentally-induced colitis.
Administration of Probiotic Bi� dobacterium lactis 420 Reverses Diabetic Status in Mice Under High-Fat DietArthur Ouwehand, PhDDanisco Health and Nutrition, Finland
Probiotics are under investigation as therapies for metabolic syndrome, which is thought to be related to the high levels of systemic infl ammation promoted by a high-fat diet. One proposed mechanism of this infl ammation is that increased fat in the gut breaks down its barrier function, allowing highly infl ammatory lipopolysaccharides (LPS), produced by Gram negative bacteria in the gut, to enter the blood and tissues. Th e probiotic Bifi dobacterium lactis 420 reverses diabetic changes and reduces fat mass in mice fed a high-fat diet while reducing blood levels of LPS and markers of infl ammation and counteracting changes in the gut microbiota.
Development of Bi� dobacterium longum infantis 35624 for a Probiotic SupplementDuane Charbonneau, PhDProcter and Gamble Company
Bifi dobacterium longum subsp. infantis 35624 is in development as a probiotic for use in treating infection and irritable bowel syndrome.B. longum dramatically reduces Salmonella colonization in mice.Ongoing studies in humans with irritable bowel syndrome have been hampered by diffi culties with the formulation of this probiotic, which have made results troublesome to interpret.
In Brief: Innovations in Probiotics Research
ongoing research projects are probing the mechanisms of pre- and probiotics in order to facilitate the transition of these agents from benchtop to marketplace.
the mechanisms of pre- and probiotics in
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Suggested Reading
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International Scienti� c Associationfor Probiotics and Prebioticswww.isapp.netTh is association is a non-profi t collaboration of scientists dedicated to advancing the science of probiotics and prebiotics.Group Danonewww.danone.comGroup Danone is a health and nutrition company that produces dairy products, bottled waters, and baby and medical nutrition products.WGO Practice Guideline - Probiotics and Prebioticswww.worldgastroenterology.org/probiotics-prebiotics.html A set of clinical practice guidelines for the use of probiotics and prebiotics from the World Gastroenterology OrganisationHuman Microbiome Projectnihroadmap.nih.gov/hmpTh e Human Microbiome Project is a research program initiated by the NIH Roadmap intended to generate resources leading to a comprehensive characterization of the human microbiota and their role in human health and disease.An Introduction to Probioticsnccam.nih.gov/health/probioticsTh e National Center for Complementary and Alternative Medicine has developed an informational page on probiotics.Dietary supplements:Industry Information andRegulationswww.fda.gov/Food/DietarySupplements/GuidanceCompliance-RegulatoryInformation/ucm107201.htmTh is page provides FDA guidance on dietary supplement labeling, new dietary ingredients, and other areas of interest to probiotic manufacturers.FDA Guidance for Industry:Evidence-Based Review System for the Scienti� c Evaluation of Health Claimswww.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/ucm073332.htmTh is page provides recent FDA guidance on the use of health claims in food product labeling.
PodcastMore � an Yogurtwww.nyas.org/morethanyogurtDelve into the world of prebiotic and probiotic science and learn why keeping the good microbes in our bodies happy means a lot for health.eBrie� ngTo watch speaker presentations and slideshows from this Symposium, please visit www.nyas.org/probiotics-eB.
Webcasts
www.usprobiotics.org/webcast.aspProbiotics: Applications in Gastrointestinal Health & Disease(October 2007)
http://nutrition.med.harvard.edu/webcast.html� e Health Impact of Active Cultures: Probiotics(September 2006)Probiotics and the Hygiene Hypothesis:A Case for Protective Nutrients(April 2006)Probiotics and Intestinal Health in Children(October 2005)
Are health claims currently allowed for probiotics in the U.S.?
No. Today only structure-function claims are currently allowed for probiotics in the U.S.
Are probiotics currently under clinical investigation for the treatment or prevention of disorders other than gastrointestinal conditions?
Yes. Because of their putative eff ects on immune function, probiotics are under clinical investigation for the treatment of infections and allergies, and in a number of other clinical settings as well.
Are studies of probiotics in humans subject to FDA oversight through the Investigational New Drug (IND) application process?
It depends. Trials in healthy individuals in which the stated aims are to evaluate structure/function claims would not ordinarily require an IND. However, an IND is likely to be required if the trial is investigating the eff ects of a probiotic on a disease condition, which would bring the research into the realm of drug investigation.
Is there any scienti� c evidence to suggest that probiotics may be useful against psychological conditions such as stress and depression, or neurophysiological states such as chronic pain?
Considerable preclinical and basic science evidence suggests intimate connections between neurophysiological states, such as mood and pain, and the gastrointestinal tract. Several lines of evidence also suggest that these states are aff ected by the composition of the gut microbiota, which may in turn be aff ected by the introduction of probiotics.
What is known about the optimal composition and the functions of the human gut microbiota?
Th ere is currently no defi nitive answer to this question. Although substantial data have been gathered on the microbial species present in the gut, the complexity of the gut microbiota has required the development of a number of model systems to investigate how these species interact with each other and the human host and to study the exact roles played by the microbiota in health and disease. Considerable research is still needed to answer these questions and to determine how probiotics might aff ect these interactions.
Resources Frequently Asked Questions
Program made possible by an unrestricted educational grant provided by Th e Dannon Company, Inc., and award 1 R13 AI088836 – 01 from the National Institute of Allergy and Infectious Diseases.
Th e views expressed in written conference materials or publications and by speakers and moderators do not necessarily refl ect the offi cial policies of the Department of Health and Human Services; nor does mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government.
