Apolipoprotein A-V (apoA-V), the newest member of the plasma apolipoprotein family, was recently discovered by comparison of the mouse and human genomes. Studies in rodents and population surveys of human apoA-V polymorphisms have noted a strong effect of apoA-V on plasma triglyceride levels. Toward the elucidation of the biologic function of apoA-V, we used spectroscopic and surface chemistry techniques to probe its structure and interfacial activity. Computer-assisted sequence analysis of apoA-V predicts that it is very hydrophobic, contains a significant amount of ␣-helical secondary structure, and probably is composed of discrete structural regions with varying degrees of lipid affinity. Fluorescence spectroscopy of recombinant human apoA-V provided evidence of tertiary folding, and light scattering studies indicated that apoA-V transforms dimyristoylphosphatidylcholine vesicles into discoidal complexes with an efficiency similar to that of apoA-I. Surface chemistry techniques revealed that apoA-V displays high affinity, low elasticity, and slow binding kinetics at hydrophobic interfaces, properties we propose may retard triglyceride-rich particle assembly. Metabolic labeling and immunofluorescence studies of COS-1 cells transfected with human apoA-V demonstrated that apoA-V is poorly secreted, remains associated with the endoplasmic reticulum, and does not traffic to the Golgi. Given that overexpression of the apoA-V gene lowers plasma triglycerides in mice, these data together suggest that apoA-V may function intracellularly to modulate hepatic VLDL synthesis and/or secretion.Lipoprotein metabolism is regulated by the plasma apolipoproteins, a family of surface-active lipid binding proteins. The smaller, exchangeable members of this family evolved from a single primordial gene to control various processes in intravascular lipid transport (1). The largest member of the family, apoB, 1 evolved from ancient lipid transport proteins involved in oogenesis (2) to play a central role in the intracellular assembly of triglyceride-rich lipoproteins in the intestine and liver. ApoA-V is the most recently described member of the plasma apolipoprotein family. Unlike all other apolipoproteins, which were identified in human plasma, apoA-V was discovered by comparative sequence analysis of the human and murine genomes as a gene on chromosome 11, downstream of the A-I/C-III/A-IV gene cluster, displaying homology to apoA-IV (3). Concurrently and independently, apoA-V was identified as a gene up-regulated in the early phase of hepatic regeneration in the rat (4). Mature human apoA-V is a 39-kDa protein with 343 residues and 27% sequence identity with human A-IV.ApoA-V was found to have a powerful effect on plasma triglycerides. Overexpression of human apoA-V in transgenic mice (3) or by use of adenoviral vectors (5) lowers plasma triglyceride levels, whereas inactivation of the apoA-V gene by homologous recombination causes a 4-fold increase in plasma VLDL triglycerides (3). Several single nucleotide polymorphisms in the a...

Objectives The objective of this study was to test the hypothesis that gastric bypass surgery (GBS) would favorably impact cardiac remodeling and function. Background GBS is increasingly used to treat severe obesity, but there are limited outcome data. Methods We prospectively studied 423 severely obese patients undergoing GBS and a reference group of severely obese subjects that did not have surgery (n = 733). Results At a 2-year follow up, GBS subjects had a large reduction in body mass index compared with the reference group (−15.4 ± 7.2 kg/m2 vs. −0.03 ± 4.0 kg/m2; p < 0.0001), as well as significant reductions in waist circumference, systolic blood pressure, heart rate, triglycerides, low-density lipoprotein cholesterol, and insulin resistance. High-density lipoprotein cholesterol increased. The GBS group had reductions in left ventricular (LV) mass index and right ventricular (RV) cavity area. Left atrial volume did not change in GBS but increased in reference subjects. In conjunction with reduced chamber sizes, GBS subjects also had increased LV midwall fractional shortening and RV fractional area change. In multivariable analysis, age, change in body mass index, severity of nocturnal hypoxemia, E/E', and sex were independently associated with LV mass index, whereas surgical status, change in waist circumference, and change in insulin resistance were not. Conclusions Marked weight loss in patients undergoing GBS was associated with reverse cardiac remodeling and improved LV and RV function. These data support the use of bariatric surgery to prevent cardiovascular complications in severe obesity.

Basolateral apoB secretion decreased. Using the same expression system, fulllength human apoA-IV (376 amino acids); a "pig-like" human apoA-IV, lacking the C-terminal EQQQ repeats (361 amino acids); and a "chicken-like" apoA-IV, further truncated to 343 amino acids, were expressed in IPEC-1 cells. With increasing protein secretion, cells expressing the full-length human apoA-IV displayed a 2-fold increase in TG secretion; in sharp contrast, cells expressing the piglike human apoA-IV displayed a 25-fold increase in TG secretion and a 27-fold increase in lipoprotein diameter. When human apoA-IV was further truncated to yield a chicken-like protein, TG secretion was inhibited. We conclude that overexpression of swine apoA-IV enhances basolateral TG secretion in a dose-dependent manner by increasing the size of secreted lipoproteins. These data suggest that the region in the human apoA-IV protein from residues 344 to 354 is critical to its ability to enhance lipid secretion, perhaps by enabling the packaging of additional core TG into chylomicron particles. The EQQQ-rich region may play an inhibitory or modulatory role in chylomicron packaging in humans.

Context Questions remain about bariatric surgery for type 2 diabetes mellitus (T2DM) treatment. Objective Compare the remission of T2DM following surgical or nonsurgical treatments. Design, setting, and participants Randomized controlled trial at the University of Pittsburgh, in the United States. Five-year follow-up from February 2015 until June 2016. Interventions 61 participants with obesity and T2DM who were initially randomized to either bariatric surgical treatments (Roux-en-Y gastric bypass [RYGB] or laparoscopic adjustable gastric banding [LAGB]) or an intensive lifestyle weight loss intervention (LWLI) program for 1 year. Lower level lifestyle weight loss interventions (LLLIs) were then delivered for 4 years. Main Outcomes and Measures Diabetes remission assessed at 5 years. Results The mean age of the patients was 47 ± 6.6 years, 82% were women, and 21% African American. Mean hemoglobin A1c level 7.8% ± 1.9%, body mass index (BMI) 35.7 ± 3.1 kg/m2, and 26 participants (43%) had BMI &lt; 35 kg/m2. Partial or complete T2DM remission was achieved by 30% (n = 6) of RYGB, 19% (n = 4) of LAGB, and no LWLI participants (P = .0208). At 5 years those in the RYGB group had the largest percentage of individuals (56%) not requiring any medications for T2DM compared with those in the LAGB (45%) and LWLI (0%) groups (P = .0065). Mean reductions in percent body weight at 5 years was the greatest after RYGB 25.2% ± 2.1%, followed by LAGB 12.7% ± 2.0% and lifestyle treatment 5.1% ± 2.5% (all pairwise P &lt; .01). Conclusions Surgical treatments are more effective than lifestyle intervention alone for T2DM treatment.

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