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Metabolic Sequelae of Bariatric Surgery
Dr Sumeet ShahLaparoscopic & Bariatric Surgeon
Sir Ganga Ram Hospital
WEIGHT LOSS SURGERYWEIGHT LOSS SURGERY
Gastric BypassGastric Bypass
Potential Consequences of Obesity
• Obesity is associated with a rise in many comorbid conditions, including:• Type 2 Diabetes• Hyperlipidemia• Hypertension• Obstructive Sleep Apnea• Heart Disease• Stroke• Asthma• Back and lower extremity weight- bearing degenerative problems• Cancer• Depression• AND MORE!
Visceral Obesity
Heart Disease, Stroke Risk
Insulin Resistance & Hyperinsulinemia
Dense LDL HDL Cholesterol
Triglycerides
Source: NAASO, 2005
The emergence of metabolic disease: a direct clinical pathway from obesityThe emergence of metabolic disease: a direct clinical pathway from obesity
Types of Bariatric Surgery
• Purely Restrictive• Gastric Balloons• Sleeve Gastrectomy• Gastric adjustable banding
• Restrictive > Malabsorptive• Short-limb/Roux-en-Y gastric bypass
• Malabsorptive > Restrictive• Biliopancreatic diversion (BPD)• BPD with duodenal switch• Long limb Roux-en-Y gastric bypass
Weight Loss Benefits vs. Nutritional Risk
0
10
20
30
40
50
60
70
Band Gastroplasty GBP DS
EWLMortalityB12 def
N Engl J Med. May 24 2007;356(21):2176-2183.
Long Term Complications: Nutritional Deficiencies
• Nutritional deficiencies are uncommon with purely restrictive procedures unless• Eating habits are excessively restricted or
complications occur (emesis)• Folate is the most common deficiency after
restrictive procedures
• Hormonal Sequelae - Human body regulates nutrient intake over time by secreting hormones. Over 40 hormones play a role in regulation of feeding.
• Nutritional Sequelae
Metabolic Sequelae
Metabolic Sequelae• Two types:
• Satiety hormones• Short-term• Help regulate meal size; daily intake• Secretion decreases meal size; reduces time to stop• Includes (among others) cholecystokinin, amylin,
glucagon-like-peptide 1 (GLP-1), enterostatin, and bombesin
• Adiposity hormones• Long-term• Related to energy stores• Secretion delays onset of beginning of meal• Includes insulin, leptin
PROTEINS: GHRELIN
• A peptide secreted by Gastric mucosa on an empty stomach (Fasting Ghrelin Levels)
• Also releases growth hormone
• Ghrelin during fasting Appetite Food intake Fat utilization
• In Obesity, GHRELIN LEVELS ARE
GHRELIN..
• Activates appetite stimulating neurons in Hypothalamus
• Short term appetite control
• Overproduction OBESITY• PRADER-WILLI SYNDROME
• Highest level of ghrelin ever measured in humans
GHRELIN
• Ghrelin levels when weight is lost while dieting• Opposes the effect of dieting
• In Gastric Bypass and Sleeve Gastrectomy, GHRELIN LEVEL at least in the short term due to exclusion/ removal of the fundus
Metabolic Sequelae
• Further investigation is needed, but the reason why certain types (i.e., RYGB/ Sleeve) of bariatric surgery are successful at reducing food intake and causing weight loss may be related to enhanced secretion of satiety signals (ghrelin or others).
Role of Incretins
GIP
• Released from K cells in duodenum
• Modest effect on gastric emptying
• No significant inhibition of glucagon secretion
• No significant effects on satiety or body weight
GLP-1
• Released from L cells in ileum
• Potent inhibition of gastric emptying
• Potent inhibition of glucagon secretion
• Reduction of food intake and body weight
Role of Incretins
GIP
• Potential effects on beta cell growth & survival
• Stimulate insulin secretion via beta cell
• Inactivation by DPP-4
GLP-1
• Significant effects on beta cell growth and survival
Regulation of Food Intake
BrainBrain
NPYAGRPgalanin
Orexin-ADynorphinECS/CB1
StimulateStimulateα-MSHCRH/UCNGLP-I
CARTNE5-HT
InibitInibit
Central SignalsCentral Signals
Glucose
CCK, GLP-1,Apo-A-IVVagal afferents
Insulin
Ghrelin
Leptin
Cortisol
Peripheral signalsPeripheral signals Peripheral organsPeripheral organs
+
+
Gastrointestinaltract
Adiposetissue
FoodIntake
Adrenal glands
External factorsEmotions, DrugsFood characteristicsLifestyle behaviorsEnvironmental cues
Modified from Marx, Science 2003 February 7; 299: 846-849. (in News)
Gastrointestinal Peptides Hormones
food intake regulation
digestion and metabolism
Anti-obesity potential
Anti-diabetes potential
Vagusnerve
Ghrelin
InsulinAmylin
Glucagon
Leptin
PYY
GLP-1
CCK
Effect on Comorbid Conditions
• Diabetes• 76.8% - Completely resolved• 86.0% - Resolved or improved
• Hyperlipidemia• 70% - Improved
• HTN• 61.7% - Resolved• 85.7% - Resolved or improved
• Obstructive Sleep Apnea• 83.6% - Resolved• 85.7% - Resolved or improved
Buchwald H, et al. Bariatric Surgery: A Systematic Review and Meta-analysis. JAMA, 14:1724-37, 2004
Metabolic Changes and Diabetes
• Many metabolic changes contribute to improvement and/or resolution of DM
• Recovery of acute insulin response• Decreases of inflammatory indicators (C-reactive
protein and interleukin 6)• Improvement in insulin sensitivity correlated
w/increases in plasma adiponectin• Changes in the enteroglucagon response to
glucose• Reduction in ghrelin levels • Improvement in beta cell function
Risk of Vitamin and Mineral Deficiencies Post-op
• Calcium and Vitamin D• Reduced absorption d/t bypassed duodenum, proximal
jejunum (R-en-Y)• Life-long supplements mandatory
• Iron• Absorption decreased d/t decreased contact of food with
gastric acid; reduced conversion of iron from ferrous to ferric form (MVI)
• Vitamin B12• Absorption decreased d/t decreased contact with intrinsic
factor• 60% of patients require long term supplementation of
B12• Thiamine
• Connection to Wernicke’s syndrome• Cases not well documented
Review: what gets absorbed where?
Recommended managementDietary modification• Reduce food volume consumed, chew food very
well, slow pace of eating• Do not consume fluids with food
• 30 minutes before or after meal• Protein rich-food should be major component of
each meal• Cheese, fish, poultry, eggs & meat• 40-60g/day after RYGB• 60-90g/day after BPD-DS
• Avoid empty calories
Recommended management
Dietary supplements• All patients should receive
• Multivitamin with iron• Vitamin B12, B complex with thiamine • Vitamin C• Calcium
• Additional supplements may be needed for menstruating or pregnant women
• Depending on procedure, patient may need fat soluble vitamin supplements (BPD)
Recommended management
Am J Med Sci. Apr 2006;331(4):219-225.
In Summary……
• Role of Gut and G I hormones • Fat as Endocrine organ• Nutritional Sequlae• Resolution of diabetes mellitus and
improvement in lipid profile central in providing metabolic role to bariatric surgery