There is a continued overall trend in the increased popularity of the SG and decreased utilization of the RYGB and LAGB, although growth of the SG appears to be slowing. This is also true among patients with type 2 diabetes mellitus. Regardless of surgery type, underinsured and African-American race were more likely to be readmitted.
Previous studies have shown that reduced levels of the adipocyte fatty acid binding protein (FABP)4 (AFABP/aP2), result in metabolic improvement including potentiated insulin sensitivity and attenuated atherosclerosis. Mechanistically, pharmacologic or genetic inhibition of FABP4 in macrophages upregulates UCP2, attenuates reactive oxygen species (ROS) production, polarizes cells toward the anti-inflammatory M2 state, and reduces leukotriene (LT) secretion. At the protein level, FABP4 stabilizes LTA toward chemical hydrolysis, thereby potentiating inflammatory LTC synthesis. Herein, we extend the FABP4-LT axis and demonstrate that genetic knockout of FABP4 reduces expression of the major macrophage LT receptor, LTB receptor 1 (BLT1R), via a ROS-dependent mechanism. Consistent with inflammation driving BLT1R expression, M1 polarized macrophages express increased levels of BLT1R relative to M2 polarized macrophages and treatment with proinflammatory lipopolysaccharide increased BLT1R mRNA and protein expression. In FABP4 knockout macrophages, silencing of UCP2, increased ROS levels and led to increased expression of BLT1R mRNA. Similarly, addition of exogenous HO upregulated BLT1R expression, whereas the addition of a ROS scavenger, -acetyl cysteine, decreased BLT1R levels. As compared with WT macrophages, LTB-BLT1R-dependent JAK2-phosphorylation was reduced in FABP4 knockout macrophages. In summary, these results indicate that FABP4 regulates the expression of BLT1R and its downstream signaling via control of oxidative stress in macrophages.
Spontaneous glycation of bovine heart cytochrome c (cyt c) by the sugar ribose 5-phosphate (R5P) decreases the ability of the heme protein to transfer electrons in the respiratory pathway and to bind to membranes. Trypsin fragmentation studies suggest the preferential sites of glycation include Lys72 and Lys87/88 of a cationic patch involved in the association of the protein with its respiratory chain partners and with cardiolipin-containing membranes. Reaction of bovine cyt c with R5P (50 mM) for 8 h modified the protein in a manner that decreased its ability to transfer electrons to cytochrome oxidase by 60%. An 18 hour treatment with R5P decreased bovine cyt c’s binding affinity with cardiolipin-containing liposomes by an estimated eightfold. A similar lower binding of glycated cyt c was observed with mitoplasts. The reversal of the effects of R5P on membrane binding by ATP further supports an A-site modification. A significant decrease in the rate of spin state change for ferro-cyt c, thought to be due to cardiolipin insertion disrupting the Met coordination to heme, was found for the R5P-treated cyt c. This change occurred to a greater extent than explained by the permanent attachment of the protein onto the liposome. Turbidity changes resulting from the multi-lamellar liposome fusion that is readily promoted by cyt c binding were not seen for the R5P-glycated cyt c samples. Collectively, these results demonstrate the negative impact that R5P glycation can have on critical electron transfer and membrane association functions of cyt c.
Background
Nearly 1/3rd of patients undergoing coronary artery bypass graft surgery (CABG) have left ventricular systolic dysfunction. However, the extent, direction and implications of perioperative changes in left ventricular ejection fraction (LVEF) have not been well characterized in these patients.
Methods
We studied the changes in LVEF among 549 patients with left ventricular systolic dysfunction (LVEF <50%) who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Patients had pre- and post-CABG (4 month) LVEF assessments using identical cardiac imaging modality, interpreted at a core laboratory. An absolute change of >10% in LVEF was considered clinically significant.
Results
Of the 549 patients (mean age 61.4±9.55 years, and 72 [13.1%] women), 145 (26.4%) had a >10% improvement in LVEF, 369 (67.2%) had no change and 35 (6.4%) had >10% worsening of LVEF following CABG. Patients with lower preoperative LVEF were more likely to experience an improvement after CABG (odds ratio 1.36; 95% CI 1.21–1.53; per 5% lower preoperative LVEF; p <0.001). Notably, incidence of postoperative improvement in LVEF was not influenced by presence, nor absence, of myocardial viability (25.5% vs. 28.3% respectively, p = 0.67). After adjusting for age, sex, baseline LVEF, and NYHA Class, a >10% improvement in LVEF after CABG was associated with a 57% lower risk of all-cause mortality (HR: 0.43, 95% CI: 0.26–0.71).
Conclusions
Among patients with ischemic cardiomyopathy undergoing CABG, 26.4% had >10% improvement in LVEF. An improvement in LVEF was more likely in patients with lower preoperative LVEF and was associated with improved long-term survival.
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