The postprandial secretion of peptide YY1-36 and 3-36 in obesity is differentially increased after gastric bypass versus sleeve gastrectomy.

OBJECTIVES: Peptide tyrosine tyrosine (PYY) exists as two species, PYY1-36 and PYY3-36 , with distinct effects on insulin secretion and appetite regulation. The detailed effects of bariatric surgery on PYY1-36 and PYY3-36 secretion are not known as previous studies have used nonspecific immunoassays to measure total PYY. Our objective was to characterize the effect of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) on fasting and postprandial PYY1-36 and PYY3-36 secretion using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay. DESIGN AND SUBJECTS: Observational study in 10 healthy nonobese volunteers and 30 participants with obesity who underwent RYGB (n = 24) or SG (n = 6) at the Imperial Weight Centre [NCT01945840]. Participants were studied using a standardized mixed meal test (MMT) before and 1 year after surgery. The outcome measures were PYY1-36 and PYY3-36 concentrations. RESULTS: Presurgery, the fasting and postprandial levels of PYY1-36 and PYY3-36 were low, with minimal responses to the MMT, and these did not differ from healthy nonobese volunteers. The postprandial secretion of both PYY1-36 and PYY3-36 at 1 year was amplified after RYGB, but not SG, with the response being significantly higher in RYGB compared with SG. CONCLUSIONS: There appears to be no difference in PYY secretion between nonobese and obese volunteers at baseline. At 1 year after surgery, RYGB, but not SG, is associated with increased postprandial secretion of PYY1-36 and PYY3-36 , which may account for long-term differences in efficacy and adverse effects between the two types of surgery.

Triglycerides: a case for treatment?

PURPOSE OF REVIEW: To discuss the relevance of triglycerides to cardiovascular disease (CVD) risk. RECENT FINDINGS: Triglycerides are a commonly measured component of lipid profiles. Raised triglycerides are a component of the metabolic syndrome and are strongly associated with future risk of diabetes as well as cardiovascular disease. Triglyceride-rich particles form a component of cardiovascular risk above that delineated by low density lipoprotein (LDL) cholesterol. Elevated triglycerides are a marker of atherogenic small dense LDL, excess baseline and residual CVD risk even after statin therapy. Additional methods to lower triglycerides include niacin, fibrates and omega-3 fatty acids. Trials in monotherapy with both niacin and fibrates suggest some benefit in reducing CVD events based on evidence mostly derived from older studies. However, endpoint trials of adding either niacin or fenofibrate to statins have not shown any benefit, except possibly in patients with an increased atherogenic index (triglyceride : HDL-C ratio), or have been underpowered. Trials of omega-3 fatty acids have been performed at doses insufficient to affect lipid profiles in populations with inadequate control of LDL-C but did reduce CVD events. SUMMARY: Further trials of lipid-lowering agents beyond statins will be required in patients with LDL-C adequately controlled on statin therapy.

Effectiveness of alternative strategies to define index case phenotypes to aid genetic diagnosis of familial hypercholesterolaemia.

OBJECTIVE: To determine the utility of secondary stratification measures to improve the ascertainment of index cases of familial hypercholesterolaemia (FH). DESIGN: A retrospective study of genotyped index patients with Simon Broome (SB) FH. SETTING: University teaching hospital. PATIENTS: 204 patients aged 55±14 years; 36% had tendon xanthoma (TX), 21% had coronary heart disease (CHD), low-density lipoprotein cholesterol (LDL-C) was 6.20±2.24 mmol/l and 55% had genetic FH. INTERVENTIONS: The effects of different staging systems (SB vs Dutch criteria), presence of TX, use of LDL-C level, personal history of CHD and imaging evidence of atheroma by carotid intima-media thickness or coronary artery calcium score to identify genetic FH was explored. OUTCOME MEASURES: Changes in C-statistic and net reclassification index (NRI). RESULTS: SB criteria gave a C-statistic of 0.64 comprising C=0.65 in TX(+) and C=0.5 in TX(-) patients. Genetic FH was present in 75% of TX(+) compared with 44% in TX(-) patients. The Dutch criteria gave C=0.72. Addition of imaging criteria to prior CHD raised C=0.64 to C=0.65 in all patients with a NRI of 19% (p=0.06). In TX(-) patients imaging raised C=0.50 to C=0.65 with a NRI of 0.38 (p=0.001) and a weighted comparison index of 0.28, implying the detection of 14 more FH cases per thousand. CONCLUSIONS: Patients with tendon xanthoma (definite FH) should be genotyped. In patients with possible FH, the presence of a personal history of CHD or imaging evidence of increased atheroma offers the best method of identifying index patients likely to have monogenic FH.