Cholesterol Metabolism After Bariatric Surgery in Grade 3 Obesity

Abstract

OBJECTIVEMalabsorptive bariatric surgery (biliopancreatic diversion and biliointestinal bypass [BIBP]) reduces serum cholesterol levels more than restrictive surgery (adjustable gastric banding [AGB]), and this is thought to be due to greater weight loss. Our aim was to evaluate the changes of cholesterol metabolism induced by malabsorptive and restrictive surgery independent of weight loss.RESEARCH DESIGN AND METHODSIn a nonrandomized, self-selected, unblinded, active-comparator, bicenter, 6-month study, glucose metabolism (blood glucose and serum insulin levels and homeostasis model assessment of insulin resistance [HOMA-IR] index) and cholesterol metabolism (absorption: serum campesterol and sitosterol levels; synthesis: serum lathosterol levels; catabolism: rate of appearance and serum concentrations of serum 7-α- and serum 27-OH-cholesterol after infusions of deuterated 7-α- and 27-OH-cholesterol in sequence) were assessed in grade 3 obesity subjects undergoing BIBP (n = 10) and AGB (n = 10). Evaluations were performed before and 6 months after surgery.RESULTSSubjects had similar values at baseline. Weight loss was similar in the two groups of subjects, and blood glucose, insulin levels, HOMA-IR, and triglycerides decreased in a similar way. In contrast, serum cholesterol, LDL cholesterol, non-HDL cholesterol, serum sitosterol, and campesterol levels decreased and lathosterol levels increased only in BIBP subjects, not in AGB subjects. A significant increase in 7-α-OH-cholesterol occurred only with BIBP; serum 27-OH-cholesterol decreased in both groups.CONCLUSIONSMalabsorptive surgery specifically affects cholesterol levels, independent of weight loss and independent of glucose metabolism and insulin resistance. Decreased sterol absorption leads to decreased cholesterol and LDL cholesterol levels, accompanied by enhanced cholesterol synthesis and enhanced cholesterol catabolism. Compared with AGB, BIBP provides greater cholesterol lowering.

Remisja cukrzycy typu 2 po leczeniu bariatrycznym — porównanie różnych procedur

“…The decrease in LDL, HDL, and total cholesterol levels was significant only in patients who underwent BPD & RYGB. In fact, Benetti et al [19] found that malabsorptive techniques are highly effective in reducing the lipid profile because the absorption of lipids seems to be lowered, which matches with our results because mixed techniques have a malabsorptive component [20]. They also note that variation in cholesterol, HDL and LDL (including sterol) synthesis, catabolism, and absorption is independent of glycaemic control and insulin resistance.…”

Impact of bariatric surgery on apolipoprotein C-III levels and lipoprotein distribution in obese human subjects

“…39 In malabsorptive surgery, it has been shown that intestinal cholesterol absorption decreases leading to decreased plasma TC and LDL-C concentrations, accompanied by enhanced hepatic cholesterol synthesis and catabolism. 40 In the present study, the greater reduction in total apoB in GBP compared with SG could be explained by a specific reduction of LDL particle numbers in GBP.…”

The Effect of Bariatric Surgery Type on Lipid Profile: An Age, Sex, Body Mass Index and Excess Weight Loss Matched Study

“…Pihlajamäki et al found a decrease in cholesterol synthesis markers 1 year after both RYGB and AGB but there was a reduction in cholesterol absorption markers only in RYGB while in AGB patients an increase was noted in such absorption markers [23]. Identical results in cholesterol absorption were reported in purely malabsorptive techniques like biliointestinal bypass [17]. RYGB is a mixed restrictive and malabsorptive technique and this last component appears to be a key factor in lowering LDL cholesterol, as it counteracts the compensatory increase in absorption after weight loss.…”

“…A still unanswered question is whether this improvement in the lipid profile is merely weight-dependent or otherwise, also results from specificities inherent to the bariatric procedure itself [6]. Current evidence points towards the importance of weight loss [13,17,18].…”