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OBESITY (cont.)

Arun ThulasiMD (Y&R)2ND Semester

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General Introduction

Environmental forces Vs. Individualgene substrate = OBESITY

Remember Overweight BMI above 27 kg/m2.

Obesity BMI above 30 kg/m2.

Fat topography has a profoundinfluence on the health risk.

White adipose tissue (WAT) is the

physiological site of energy storage

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PREVALENCE

As of 2008, The World HealthOrganization claimed that 1.5 billionindividuals over the age of 20 are

considered obese .

The rate of obesity also increaseswith age at least up to 50 or

60 years old .

By 2015, WHO estimates thatapproximately 2.3 billion adults will

be overweight and more than 700

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PATHOGENESIS

1) Gene susceptibility

1) Fat cell & obesity

1) Environmental factors

1) Pro-inflammatory factors

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1. Gene susceptibility

Extensive studies have indicated that30-50 % of the fat variability is believed

to be genetically determined.

Mainly 4 genes have been identified thatis believed to be causing obesity:

i. Leptin gene (mainly)

ii. 3 adregenic receptor gene

iii. TNF gene overall contribution is

small

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Leptin gene

Leptin is one moleculethat provides for thiscoupling between

energy intake andenergy expenditure.

Leptin protein is

normally secreted fromfat cells itscirculating levels are

high in obesity.

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2. Fat cell & obesity

Most forms of obesity are associated

with enlarged fat cells. Fat cells fat storage + secretory

organ

Fat cell generates lots of lactate glucose metabolism glycerol-3-phosphate TG synthesis

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3. Environmental factors:

Environmental factors interact with

genetic susceptibility.

E.g.: hypothalamic injury (trauma)

lesion in ventromedial nucleus

hyperphagia OBESITY

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4. Pro-inflammatory factors:

What is adiponectin?

o It is an insulin-sensitising effector, whichhelps to counteract the effects of obesity.

o circulating adiponectin levels aredecreased in obesity-related insulinresistance, type 2 diabetes and coronaryheart disease.

o

It inhibits liver neoglucogenesis andpromotes fatty acid oxidation in skeletalmuscle.

o

It counteracts the pro-inflammatory effectsof TNF- on the arterial wall

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WAT infiltrated by macrophages

Pro-inflammatory cytokines produced(leptin,TNF- ,IL-6,resistin)

Insulin resistance adiponectin

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Other factors that affectobesity

Hypothyroidism Medications such as birth control

pills, antidepressants, and

antipsychotics. Menopause (oestrogen affects

obesity).

Pregnancy ( glucose homeostasis &fat oxidation are all disrupted bymaternal obesity)

uittin smokin nicotine

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Some researches

Risk for Alcoholism Linked toRisk for Obesity

(reward centre)

-Science Daily (Dec. 31, 2010) How Fatty Diets Cause Diabetes

(damage of glycosyltransferase)

-ScienceDaily (Aug. 15, 2011)

Link Between Brain Molecule and

Obesity and Diabetes Discovered

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Related with yoga.

Yoga Reduces Cytokine LevelsKnown to Promote Inflammation

ScienceDaily (Jan. 14, 2010)

o Many of the metabolic disturbancesassociated with obesity and themetabolic syndrome may be due to

cytokine production by adipocytes.o Particularly IL-6, associated with stress,

reduced with yoga practice.

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Regular Yoga Practice IsAssociated With Mindful Eating

ScienceDaily (Aug. 16, 2009)

o Mindful Eating- those were aware of whythey ate and stopped eating when full.

o A strong association between yogapractice and mindful eating

o no association between other types ofphysical activity, such as walking or

running, and mindful eating

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Yoga's Ability to Improve Moodand Lessen Anxiety Is Linked toIncreased Levels of a CriticalBrain Chemical, Research Finds

- [ ScienceDaily (Nov. 12, 2010) ]

o GABA is the chief inhibitoryneurotransmitter which regulates

neuronal excitability; associated withanxiety.

o Brain GABA increases with fat feeding;

balances between energy dense diet &su ression of food.

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Thankyou