Adipocytes, Obesity, Bariatric Surgery

and its Complications

Daniel C. Morris, MD, FACEP, FAHA

Senior Staff Physician

Department of Emergency Medicine

Objectives

Basic science of adipocyte

Adipocyte tissue as an endocrine organ

Inflammatory response of obesity

Types of bariatric surgery

Complications and treatments

Too many calories in…………….

Not enough calories out.

Morbidity and Mortality

• Type 2 diabetes

• Hypertension

• Cardiovascular and Kidney disease

• Bone and Joint problems

• Increased risk of Cancer

Gene-Environment

Adipocyte

The classic function of the adipocyte is to store and

release lipid fuel.

Adipocytes can vary in size from 20 to 200 µm.

Adipose tissue can be divided into brown and white.

Brown adipose tissue is thermogenic whereas white

adipose tissue is primarily for storage.

Adipose deposits can be intracellular,

interorgan and subcutaneous.

Adipocyte

Approximately 90% of the adipocyte is triglyceride

storage.

The remaining 10% consists of nucleus, cytoplasm,

mitochondria and other organelles.

Hyperplastic obesity

Hypertrophic obesity

Classification of obesity

increase in adipocytes

juvenile onset obesity

Adipocytes are increased in

number rather than in size. The

number of cells can never be

reduced making it difficult to

reduce body fat. Critical times

are:

last trimester of mother's

pregnancy

first year of life

puberty

increase in adipocyte size

adult onset obesity

Adipocyte size increases when

lipid storage exceeds oxidation

release.

Hyperplastic obesity can be

reduced by increasing activity or

by reducing food intake.

Hyperplastic Morphology Hypertrophic Morphology

Basic Science of Adipose Tissue:

Fat is an endocrine organ

In 1994, Leptin was found to originate from the

adipocyte. Since then, over three dozen biochemical

products have been found in the adipocyte.

With the combination of specific receptors and

production of endocrine and steriodogenic enzymes,

the adipocyte performs specific functions in

metabolism.

Adipose tissue obesity sets up a chronic

inflammatory response

Mechanism of chronic inflammation

Obesity alters the production and

secretion of adipokines

Anti-inflammatory

Pro-inflammatory

Release of pro-inflammatory

adipokines results in atherosclerosis

Adiponectin (protective)

Leptin (inflammatory)

Leptin enters the hypothalamus Activates the immune system

Leptin Mutation

Interleukin 6 (IL-6) and Tissue Necrosis

Factor (TNF)

Adipokine

Insulin resistance

Visceral adipose tissue

releases IL-6 directly

into the portal system

Adipokine

Development of type

2 diabetes

Insulin resistance

IL-6 TNF

Evolutionary Advantage?

Quickly store excess calories—Sedentary lifestyle?

Immune system is confused by modern diet

(pathological diet?) and activity levels

Metabolic disease is caused by lipids that are

stored in the wrong areas.

Overproduction of adipokines have

wide systematic implications in overall

health of the individual

Definition of Obesity

Body Mass Index (BMI)

Waist Circumference

Distribution of adipose tissue is the

most important determinant of

health and disease

Treatment of Obesity

Diet and exercise

Pharmacologic management- Inadequate long-term

clinical efficacy or unacceptable side effects (anal

leakage?)

Bariatric Surgery- intervention that consistently

induces sustained weight loss

Bariatric Surgery

Roux-en-Y gastric bypass (common)

Sleeve gastrectomy (common)

Laparoscopic adjustable gastric band (uncommon)

Biliopancreatic diversion with duodenal switch (rare)

Indications for Bariatric Surgery

BMI > 40 kg/m² without comorbid conditions

BMI between 35 kg/m² and 40 kg/m² with

significant comorbidity (diabetes, HTN, apnea)

Candidates must have tried and failed nonsurgical

weight loss measures

Mechanisms of Weight Loss

Stabilizes glucose levels

Increases metabolism

Behavioral changes in eating habits through

alteration of gastro- and neuro- peptides

Alteration of gut microbes suggesting that metabolic

regulation begins in the gut.

Weight loss is not necessary due to smaller stomach

Roux-en-Y gastric bypass

Roux-en-Y Gastric Bypass

Common procedure.

Restrictive and malabsorptive.

Reduces the amount of food ingested.

Bypasses a segment of the small bowel

leading to incomplete digestion.

Produce and maintain excess weight loss of 60% to

80% at 5 years.

Procedure can be performed both open or by

laparoscope.

Early Major Complications

Anastomotic leak with abscess: first few weeks

presenting with fever and tachycardia. Incidence in

Michigan < 1%. Common site is the

gastrojejunostomy.

Intra-abdominal or intraluminal bleeding: occurs at

the staple lines. Diagnosis is confirmed by

endoscope and most bleeding is treated

nonoperatively.

DVT or pulmonary embolism.

Abdominal Examination

Commonly unrevealing even with significant

pathology.

Obstruction in the bypassed segment will produce

vague symptoms.

Acute Abdominal Series will show no air fluid levels

and is of limited use.

CT abdominal is test of choice

Patients can sip contrast over 3 hours (230-300 ml).

Deteriorate rapidly so early consultation is

preferred.

Transverse CT images show normal postoperative anatomy in the gastrointestinal tract, including (a) a

small gastric pouch (solid arrow) and gastric staple line (open arrow)

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

Leak from gastrojejunal anastomosis in a 41-year-old woman 9 days after

gastric bypass surgery.

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

Edema at the jejunojejunal anastomosis with resultant reflux of oral contrast material

into the excluded stomach in a 52-year-old woman 4 days after gastric bypass surgery.

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

Decompression performed with a percutaneous 8-F pigtail catheter

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

Late Complications: Anatomic and Systemic

Anatomic: bowel obstruction, adhesions, strictures or

internal hernias.

Progressive inability to tolerate solids or liquids.

Anastomotic strictures can be managed

endoscopically with balloon dilatation.

Small-bowel obstruction caused by stenosis of the jejunojejunal anastomosis in a 27-

year-old woman 10 days after gastric bypass surgery. Dilated proximal efferent loop of

small bowel (arrow)

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

36-year-old woman with dysphasia after gastric bypass

surgery.

Jha S et al. AJR 2006;186:1090-1093

©2006 by American Roentgen Ray Society

29-year-old woman with epigastric pain after gastric bypass

surgery.

Jha S et al. AJR 2006;186:1090-1093

©2006 by American Roentgen Ray Society

Internal Hernia: Mesocolic defect results in protrusion of

multiple loops of small bowel resulting in obstruction.

Internal Hernias-Symptoms

Intermittent, crampy, epigastic abdominal pain that

radiates to the back.

Normal examination

20% will have normal CT scans and/or normal labs.

Other CT scans will show the “swirl sign (twisting of

the mesentery)” or obstruction.

Transmesocolonic internal hernia in a 50-year-old woman 3 months after

gastric bypass surgery.

Yu J et al. Radiology 2004;231:753-760

©2004 by Radiological Society of North America

Systemic Late Complications

Nutritional deficiencies: Iron, Wernicke’s (B1),

vitamin B12, Vitamin D and calcium.

Secondary hyperparathyroidism: increased bone

turnover and decreased bone density.

Malabsorption of vitamin D leads to reduced

calcium absorption by the intestine leading to

hypocalcaemia and increased parathyroid hormone

secretion.

Sleeve gastrectomy

Sleeve gastrectomy

Equal with bypass. Restrictive and resective.

Longitudinal gastric resection, initially performed as

a treatment for peptic ulcer disease. Creates a

gastric tube by resecting the greater curvature of

the stomach. Performed open or by laparoscope.

Less risk of nutritional deficiencies.

Weight loss ranged from 33 to 85%.

Lower rate of resolution of diabetes mellitus and

hypertension.

Early Complications

Gastric Leak: occurs at staple lines at the

angle of His and requires external

drainage or endoscopic stent placement.

Intra-abdominal bleeding: occurs at the

staple lines. Diagnosis is confirmed by

endoscope and most bleeding is treated

nonoperatively.

DVT or pulmonary embolism.

Late Complications

Bowel obstruction and adhesions. Rare with

laparoscopically performed procedures.

Gastroesophageal reflux disease (GERD): is

temporary and is gone by 3 months. Most GERD is

related to undiagnosed hiatal hernia. Surgeons

explore for hiatal hernia and repair at surgery.

Comparison of Bypass and Sleeve

Sleeve Gastrectomy has improved safety profile

compared to Bypass.

Lower rate of resolution of diabetes mellitus and

hypertension.

Mean excess weight loss approaches that of bypass

Laparoscopic adjustable gastric band

Laparoscopic adjustable gastric band

LAP-BAND (INAMED Health, Santa Barbara, CA)

Adjustable silastic band that is positioned around

the upper portion of the stomach to

create a 30 cc pouch.

The port allows the band to be

tightened or loosened.

Regulate the degree of restriction

postoperatively, easily reversed. Outpatient

surgery. Purely restrictive option.

Complications

Early: vomiting as a result of edema or proximal

movement of the band.

Late: Migration or slippage of the stomach resulting

in gastric dilatation. Gastric necrosis or perforation.

Deflation of the band can prevent obstruction.

Late: Gastric erosion occurs when band erodes the

stomach wall. Presents with sepsis, abscess or

fistulas.

Infection of the port site or device malfunction.

Comparison of Bypass and Band

Banding produces much less weight loss compared

to bypass (40.4% versus 74.6%). Better efficacy in

patients <40 years and BMI <50 kg/m².

Mechanical complications.

Patients prefer the device as the procedure is

outpatient.

Fewer metabolic derangements and lower mortality.

Long term outcomes show band device complications

and inadequate weight loss requiring removal of

the device (30%).

Biliopancreatic diversion with duodenal

switch

Biliopancreatic diversion with duodenal

switch

Technically complex procedure.

Both restrictive and malabsorptive option.

Allows for a large amount of weight loss while

preventing the development of the dumping

syndrome.

Decreasing the size of the stomach and

bypassing the duodenum.

Complications

Anastomotic leak with abscess.

Intra-abdominal bleeding

DVT or pulmonary embolism.

Bowel obstruction, adhesions, strictures or internal

hernias.

Nutritional deficiencies: Iron, Wernicke’s (B1),

vitamin B12, Vitamin D and calcium.

Fat-soluble-vitamin deficiencies. Selenium and zinc

deficiencies.

Hepatic dysfunction leading to jaundice and failure.

Summary

Conclusions

Obesity is a multifactorial disease with metabolic

consequences.

Adipocyte tissue (Fat) is an endocrine organ

Adipocytes have a limited lipid storage ability;

exceeding that limit sets up an inflammatory

response.

Bariatric surgery, specifically gastric bypass, is an

efficacious treatment for morbid obesity

Complications are common and can be life-

threatening.

Conclusions

High suspicion for complications when bariatric

surgery patients present to the ED.

Early complications are obstruction, leaks, bleeding

and PE.

Late complications are internal hernias, band slips,

erosions and strictures.

Eat your fruit and vegetables.