The target of rapamycin complex 2 (TORC2) is an evolutionarily conserved serine/threonine protein kinase that controls growth and metabolism. In mammals (including humans), mammalian TOR complex 2(mTORC2) contains mammalian TOR (mTOR), RICTOR, mSIN1 protein, and mLST8 gene. In an animal model, the adipose-specific rictor knockout (AdRiKO) mouse, systemic insulin resistance, hepatic steatosis, and cardiovascular dysfunction develop upon high fat diet (HFD)-induced obesity or aging. To find a molecular link between adipose mTORC2 and systemic insulin resistance, investigators have already performed transcriptomics and proteomics analysis on visceral white adipose tissue in a mouse model. The aim of the study is to confirm a molecular link between adipose mTORC2 and systemic insulin resistance in humans.

Inclusion Criteria:

• Obese volunteers (BMI > 35kg/m2) aged 18 to a maximum of 60 years, males and females; insulin-resistant, scheduled for elective bariatric surgery.
• Normal weight patients (BMI < 27kg/m2) aged 18- max. 60 years, males and females; insulin-sensitive, scheduled for elective surgery.

Exclusion Criteria:

• Known diabetes mellitus
• Chronic inflammatory disease (inflammatory bowel disease, rheumatoid disease, cancer)
• Acute inflammatory disease
• Known renal disease: kidney failure
• Pregnancy:
• history of gastrointestinal surgery with major changes to the gastrointestinal tract (removal of stomach, any GI-bypass)
• Substance abuse, alcohol abuse
• Inability to follow procedures due to psychological disorders, dementia
• insufficient knowledge of project language (German)

Obese patients (BMI >35 kg/m2) with insulin resistance and lean controls (BMI < 27kg/m2) scheduled for elective surgery for non-inflammatory conditions such as gallstone disease, diverticular disease or - in the case of obese subjects - bariatric surgery