Patients on a statin regimen have a decreased risk of death due to bacterial sepsis. We have found that protection by simvastatin includes the inhibition of host cell invasion by Staphylococcus aureus, the most common etiologic agent of sepsis.
Jun LS, Siddall CP, Rosen ED. A minor role for lipocalin 2 in high-fat diet-induced glucose intolerance. Am J Physiol Endocrinol Metab 301: E825-E835, 2011. First published July 19, 2011 doi:10.1152/ajpendo.00147.2011.-Adipose tissue controls energy homeostasis and systemic insulin sensitivity through the elaboration of a series of cytokines and hormones, collectively termed "adipokines." We and others have identified Lcn2 as a novel adipokine, but its exact role in obesity-induced insulin resistance remains controversial. The aim of this study was to examine the metabolic phenotype of Lcn2 Ϫ/Ϫ mice to clarify the role of Lcn2 in metabolism. Male and female Lcn2Ϫ/Ϫ and wild-type (WT) littermates were placed on either chow or high-fat diet (HFD) to characterize their metabolic phenotype. Studies included body weight and body composition, glucose and insulin tolerance tests, and adipokine expression studies in serum and in white adipose tissue (WAT). Neither chow nor HFD cohorts showed any differences in body weight or body composition. Chowfed Lcn2 Ϫ/Ϫ mice did not exhibit any difference in glucose homeostasis compared with WT mice. Fasting serum glucose levels were lower in the chow-fed Lcn2 Ϫ/Ϫ mice, but this finding was not seen in the HFD cohort. Serum adiponectin, leptin, resistin, and RBP4 levels were not different between WT and Lcn2 Ϫ/Ϫ on chow diet. HFD-fed male Lcn2
Circulating increases in branched chain amino acid (BCAA) levels have long been associated with type 2 diabetes and metabolic syndrome. Emerging data also suggest that BCAA catabolism may play a role in heart failure progression. It is hypothesized that decreased catabolism, rather than increased consumption of BCAAs, is responsible for these correlations. Branched chain ketoacid (BCKA) dehydrogenase (BCKDH) kinase (BCKDK) is a negative regulator of BCAA catabolism through its inhibitory phosphorylation of the BCKDH E1a subunit. Using the BCKDK inhibitor molecule BT2, we demonstrate here a reduction of BCAA, BCKA and tissue p-BCKDH levels concomitant with improved glucose tolerance and reduced insulin levels in diet-induced obese mice after only one day of treatment. To investigate the mechanisms underlying this protection, we assessed plasma biomarkers and tissue gene expression after fasting and re-feeding in glucose intolerant high fat diet-fed animals. Remarkably, BT2 treated animals demonstrated reduced plasma glucose levels after re-feed, which was accompanied by dramatic reductions in plasma insulin levels, reduced activation of Akt in peripheral tissues, and a failure to suppress plasma free fatty acids and lipolytic machinery in adipose tissue. RNAseq was performed in liver to assess changes in gene expression profiles, and while over 400 genes were differentially regulated in vehicle treated re-fed mice compared with vehicle treated fasted mice, there were no differentially regulated genes in BT2 re-fed animals compared with BT2 fasted animals. These data suggest that activation of BCAA catabolism with the BCKDK inhibitor BT2 impairs the systemic response to feeding.
Disclosure
E. Bollinger: Employee; Self; Pfizer Inc. C.P. Siddall: Employee; Self; Pfizer Inc. Employee; Spouse/Partner; Vertex Pharmaceuticals. T. Greizer: None. J.L. Libera: None. G. Hariri: None. E.E. Pashos: Employee; Self; Pfizer Inc. A. Shipstone: None. A. Hadjipanayis: None. Z. Sun: None. G. Xing: None. M.F. Clasquin: Employee; Spouse/Partner; Merck & Co., Inc. Employee; Self; Pfizer Inc. B.B. Zhang: Employee; Spouse/Partner; Janssen Pharmaceuticals, Inc. Employee; Self; Pfizer Inc. Other Relationship; Self; Eli Lilly and Company. R.A. Miller: Employee; Self; Pfizer Inc. R. Roth Flach: Employee; Self; Pfizer Inc.
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