بسم الله الرحمن الرحيم

Obesity and diseases of civilization

By Amr Abdelmonem,MD.Assistant professor of anesthesia ,surgical intensive care and clinical nutrition in faculty of medicine, Cairo university

Member of North American Association For The Study Of Obesity

Member of the American society of regional anesthesia and pain medicine

The O Word:Obesity

1998, world health organization defined overweight and obesity based on

Body Mass Index ( BMI Kg / m2)Over weight : 25.0 to 29.9Class 1 obesity: 30.0 to 34.9Class 2 obesity: 35.0 to 39.9Class 3 obesity : 40.0 or greaterBMI is not a measure of body compositionBMI is an important correlate of impairedHRQL(health related quality of life)

National institutes of health of the US have recently recommended weight Management based on

Standardized cut- offs for BMI at 25 and 30 Kg/m2

and

On waist circumference ( action levels)Minimum circumference between lower rib margin and iliac crest

Action level 1 at 94 cm in men and 80 cm in womenAction level 2 at 102 cm in men and 88 cm in women•Greater than action level 1 : individuals are at increased health risk ,should avoid weight gain •Greater than action level 2 : are at high health risk ,should seek Professional helpNICK CIRCUMFERENCE measurement is a simple and time-saving screening measure that can be used to identify overweight and obese patients.

Men with NC <37 cm and women with NC <34 cm are not to

be considered overweight

Adipose Tissue vs. Fat

Traditional Adipose Tissue Classification

• Classical anatomy was mainly organ-centered, without recognizing the specialized organ-like functions of different tissues

• This was especially true of adipose tissue, which only recently has been recognized as an "endocrine organ “

N Engl J Med .2001;345:1345

• Simple anatomic adipose tissue groupings :subcutaneous adipose tissue, organ-surrounding adipose tissue, interstitial adipose and adipose tissue in bone marrow

• Adipose tissue is also named according to special biological functions, such as white, mammary gland, brown, and bone marrow adipose tissues

Recent proposed Classification of total body adipose tissue

Shen et al,Obes Res.2003;11:1

Subcutaneous

Superficial

Deep

Internal

Visceral Non- visceral

Intrathoracic

Intrapricardial

Extrapricardial

Intraabdominopelvic

Intraperitoneal Extrapritoneal

Preperitoneal Retrroperitoneal

Intraabdominal Intrapelvic

ParametrialRetropubicParavesical

Retrouterine Pararectal Retrorectal

IntramuscularPerimuscular

Orbital

Metabolic syndrome

What is metabolic syndrome?

• Metabolic syndrome is a collection of health risks that increase the chance of developing heart disease, stroke, and diabetes.

• The condition is also known by other names including Syndrome X, insulin resistance syndrome, and dysmetabolic syndrome.

What are these health risks?ATP III Guidelines WHO Guidelines

Abdominal Obesity 

Waist Circumference Waist/Hip Ratio Men > 40 inches  >0.90 Women > 35 inches  >0.85

Other Variables Triglycerides 150 mg/dL 150 mg/dLHDL-Cholesterol Men < 40 mg/dL <35 mg/dL Women < 50 mg/dL <39 mg/dLBlood Pressure 130/ 85 mm Hg >140/>90 mm HgFasting Glucose 110 mg/dL 110 mg/dLWHO guidelines also include microalbuminuria (>20 µg/min or albumin:creatinine ratio >30 mg/g).

The pathogenesis of metabolic syndrome

Complex interplay of a still largely unknown genetic background with environmental lifestyle- related factors

Genetic Background

Environmental lifestyle-related factors:

When we eat ,our bodies break down the food into its basic components ( protein- carbohydrates- fat), and absorbs them into blood stream rise in blood sugar pancreas will release insulin moves sugar into cells either burned for energy or stored away as fat in fat cells or glycogen in liver and muscles

Years of dietery abuse in susceptible patients malfunctioning of insulin sensors hyperinsulinemia

Continued dietery abuse insulin sensors to sluggish insulin resistance

The link between visceral adipose tissue and metabolic syndrome

• Direct exposure of liver cells through the portal circulation to high concentrations of free fatty acids derived from visceral adipose tissue is responsible for metabolic complications of abdominal obesity

Gabrielsson et al,Obes Res.2003;11:699

• Adipocytokines (leptin ,adiponectin) factors released from adipose tissue responsible for mediating insulin resistance.

Pischon et al,Obes Res.2003;11:1055

Markers of insulin resistance :

Hypertriglyceridemia

HDL

Hypertension

Hyperinsulinemia

Abdominal obesity

Hyperglycemia

Recently Marjo etal , proven liver fat accumulation as an important marker

( Obes Res 2002; 10: 859)

Obesity Lets walk through the fat metabolism pathway and follow the flow of fat molecules:

Fat travels in the form of triglycerides at cells ezymatic breakdowen fatty acids enter the cells mitochondria breakdowen fat in order to enter mitochondria ,fats need carnitine

insulin inhibitsFat- carnitine shuttle system fats move back into blood

Glucagon accelerates this shuttle system

Muscle ,liver, kidney, lung, heart and other cells break down fat

Two enzyme systems on the surface of fat cells regulated by insulin and glucagon

Insulin stimulates lipoprotein lipase that transports fatty acid into fat cells

Glucagon stimulates sensitive lipase that releases the fat from fat cells into the blood

Although we cannot control lipoprotein lipase directly, we can control It indirectly by cotrolling the metabolic hormones ,insulin and glucagon

Fat cells merely store the fat molecules !

Functions of cholesterol :• Adrenal hormones and sex hormones• Main component of bile acids• Essential for normal growth and development of

brain and nervous tissue• Gives the ability of skin to shed water • Precursor of vitamine D in the skin• Normal growth and repair of tissues• Transportation of triglycerides

DYSLIPIDEMIA

Where does cholesterol come from?

80 % comes from the body itself , every cell in the body is capable of making its own cholesterol , most don’t and rely instead on that made in the liver and skin.

Cholesterol and triglycerides are insoluble in blood

Lipoproteins are envelops that enclose cholesterol and triglycerides Making them soluble in blood,so that they can be transported to tissues

Sequence of events in the life of lipoproteins

Liver Makes and release VLDL

TRIGLYCERIDES WITH CHOLESTEROL

TRI AND CHOLES MATUREVLDL

TriglyceridesReleased to bloodAnd tissues

CholesterolBulk +tri LDL

HDL

Scavenges cholesterlFrom tissues carriesThrough bloodHands it off to

VLDL

More triglycerides release

Removed by liver

CholesteroLrich

LDL

Released to tissuesDeposited in coronary arteries

When the level of cholesterol inside the cells falls LDL receptors Attach to the surfaces of the hepatic cells invaginate LDL cholesterol By endocytosis

Obese patients with insulin resistance have LDL receptors dysfunction

Cholesterol synthesis inside the cells depends on an enzyme named3- hydroxy-3 methyl-glutaryl-coenzyme A reductase

Couple of hormones affect the activity of the rate limiting enzymeHMG-CoA reductase

INSULIN AND GLUCAGON

Diet and cholesterol quiz

Patient with the following finding

Total cholesterol: 240 LDL : 160 HDL:35Total/ HDL: 6.85 LDL/HDL: 4.57

Diet 1 Diet 2

Total cholesterol 159 mg/dl 191 mg/dl

LDL 111 mg/dl 139 mg/dl

HDL 32 mg/dl 42 mg/dl

Total /HDL 4.97 4.55

LDL/HDL 3.47 3.31

Which is better?

Hypertension

Data from NHANES III show that the (age – adjusted prevalence) Of high blood pressure increases progressively with higher levels Of BMI in men and women

High blood pressure is defined as

SBP 140 mm Hg or MBP 90 mm Hg or currently taking antihypertensives

What is the etiology that connects obesity and hypertension?

Hyperinsulinemia and insulin resistance

Mechanism

1. Increased sodium retention

1. Increased sympathetic nervous system activity

1. Alteration in the mechanics of blood vessels

However

It is known that weight loss is associated with

vascular resistance,total blood volume and cardiac output

•Improvement in hyperinsulinemia and insulin resistance

• sympathetic nervous system activity

•Suppression of the activity of renin angiotensin aldosterone system

•Recently ,serum angiotensin converting enzyme activity declines with modest weight loss.

The precise mechanism whereby weight loss

results in a decrease in Blood pressure is unknown .

Type II Diabetes mellitus

• It represents 90% of all cases of diabetes.• Requires years of underlying metabolic

disturbance before symptoms become apparent

• The development and diagnosis usually follows weight gain

• In Type I and Type II diabetes blood sugar is elevated but for different reasons

•Type I there is no insulin to hold it down by moving it into cells

•Type II the cells become resistant to insulin that even large amounts cant adequately move the sugar into cells

•In early stages there is hyperinsulinemia ,later pancreatic beta cells wear out from constantly producing insulin under stimulation of hyperglycemia

•Resistin is a protein secreted by fat cells as a signal from adipose tissue linking obesity to insulin resistance and type II diabetes Liese et al, Eur J Nutr.2001;40:282

•Increased White blood cell count is correlated with insulin resistance in diabetic obese females

Pannacciulli et al,Obes Res.2003;11:1232

Coronary artery disease • Observational studies have shown that

overweight,obesity, and VAT are directly related to cardiovascular risk factors

( cholesterol , LDL, triglycerides, hypertension, fibrinogen,hyperinsulinemia , HDL, plasminogen activator inhibitor )

RECENTLYComplement 3 and acute phase proteins is the immunological link between central obesity and CHD

The term "Syndrome X" refers to a heart condition where chest pain and electrocardiographic changes that suggest ischemic heart disease are present, but where there are no angiographic findings of coronary disease.

•Recent studies have shown that risks of nonfatal myocardial infarction and CHD death increase with increasing levels of BMI

•In British, Swedish, Japanese and US populations , CHD incidence increased at BMIs above 22 and an increase of 1 BMI unit was associated with 10 % increase in the rate of coronary events

•Recent study has found that obese CHD patients are younger and and are hospitalized more frequently during the first 10 years of their illness than the non-obese

Obesity and cardiac dysrhythmias(prolonged Q-T interval)

• Q-T interval is usually measured in lead II , and is corrected for heart rate .

• Q-Tc= measured Q-T square root of R-R interval• Prolonged Q-T interval reflects prolonged

repolarization of the ventricle• Proposed mechanism is increased SNS activity• Recent study had found that Prolonged Q-T

interval is associated with abnormal WHR ,higher levels of FFA and hyperinsulinemia in obese women .

• Wight loss leads to normalization of Q-Tc with attenuation of hyperinsulinemia

Esposito et al,Obes Res.2003;11:653-659

Oxidant Stress

Imbalance

Between

Formation Of Reactive oxygen/nitrogen species (ROS/RNS)

And Antioxidants

Pathologic stress Induces monocytes to release mediators

(TNF and interleukins 1-6-8) Activates PMNs

Release ROS(superoxide (O2·-), hydrogen

peroxide, hypochlorite, nitric oxide (NO), hydroxyl radical

Induce tissue injury by:1. damaging DNA2. Cross linking cellular proteins3. Peroxidation of membrane lipids • Diminishing membrane fluidity• Increasing membrane permeability

Oxidant Stress and Obesity

•Adipocytes and preadipocytes have been identified as sources of inflammatory cytokines:

including TNF- , interleukin (IL)1-ß, and IL-6.

•Stimuli capable of inducing cytokine release from adipocytes may include:

lipopolysaccharides, intracellular triglycerides, and catecholamines

http://www.obesityresearch.org/cgi/content/full/10/9/964/F2

We could predict that:

•The accumulation of intracellular triglycerides or tissue adiposity promotes increased oxidant stress

•Therefore reduction of total body fat through diet and/or exercise may be an effective means of reducing systemic inflammation and oxidant stress.

Consistent with this prediction

Reductions in plasma markers of oxidant stress and in ROS generation by isolated leukocytes have been observed after 4 weeks of energy restriction and weight loss.

Dandona et al. J Clin Endocrinol Metab,2001; 86:355-363

Good news

Physical activity •Decreases adipose derived inflammatory mediators •Activates signaling pathways that lead to increased synthesis of intracellular antioxidants and antioxidant enzymes and decreased ROS production Miyazaki et al, Eur Appl Physiol.2001; 84:1-6 Pischon et al, Obes Res.2003;11:1055

Obesity And Diseases

Obesity and cancer

• Strong risk factor for esophageal cancer

• Uterine and gall bladder cancer in obese women

• High risk for colon and prostate cancer in obese males

• Breast cancer for obese postmenopausal women

Obesity and muscles and bones

• Obesity places stress on bones and muscles

• High risk for hernias ,low back pain and aggravation of arthritic conditions

• High risk for carpal tunnel syndrome

Obesity and gallstones

• The incidence of gallstones is significantly higher in obese women and men

• The risk of stone formation is also high if a person loses weight too quickly

Obesity and lungs

• Strong risk factor for adult onset asthma.

• Increased risk of hypoxemia and detrimental work of breathing

• Pickwickian syndrome

Obesity and sleep apnea and sleep disorders

• Obese tend to fall asleep faster and sleep longer during the day

• At night ,it takes them longer to fall asleep they sleep less than others.

• When the upper airways relaxes and collapses at intervals during sleep ,thereby temporary blocking the passage of air (sleep apnea)

• Symptoms :morning headach,fatigue and irritability

• Side effects :dysrhythmias,stroke ,right sided heart failure and car accidents

• Sleep apnea deprives patients from REM sleep• REM sleep: the dreaming phase of sleep,necessry

for emotional wellbeing• Obesity leads to sleep apnea which leads to loss

of REM sleep which leads to raising of BMI

OBESITY AND EATING DISORDERS

• Binge eating : about 30% of obese are binge eaters ,who typically consume 5000 to 15000 calories in one sitting

• To be diagnosed as a binge eater ,person has to binge twice a week for 6 months

• Bulimia : binge eating followed by purging in order to lose weight

• Anorexia : severe weight loss and is life threatening

Why treat overweight and obesity?

Not only to improve the BODY IMAGE But also to reduce the OBESITY –RELATED COMORBIDITIES