Subacute endotoxemia induces adipose inflammation and changes in lipid and lipoprotein metabolism in cats

Endocrinology. 2011 Mar;152(3):804-15. doi: 10.1210/en.2010-0999. Epub 2011 Jan 25.

Abstract

Acute inflammation in humans is associated with transient insulin resistance (IR) and dyslipidemia. Chronic low-grade inflammation is a pathogenic component of IR and adipose tissue dysfunction in obesity-induced type 2 diabetes. Because feline diabetes closely resembles human type 2 diabetes, we studied whether lipopolysaccharide (LPS)-induced subacute inflammation, in the absence of obesity, is the potential primary cause of IR and metabolic disorders. Cats received increasing iv doses (10-1000 ng/kg(-1) · h(-1)) of LPS (n = 5) or saline (n = 5) for 10 d. Body temperature, proinflammatory and metabolic markers, and insulin sensitivity were measured daily. Tissue mRNA and protein expression were quantified on d 10. LPS infusion increased circulating and tissue markers of inflammation. Based on the homeostasis model assessment, endotoxemia induced transient IR and β-cell dysfunction. At the whole-body level, IR reverted after the 10-d treatment; however, tissue-specific indications of IR were observed, such as down-regulation of adipose glucose transporter 4, hepatic peroxisome proliferative activated receptor-γ1 and -2, and muscle insulin receptor substrate-1. In adipose tissue, increased hormone-sensitive lipase activity led to reduced adipocyte size, concomitant with increased plasma and hepatic triglyceride content and decreased total and high-density lipoprotein cholesterol levels. Prolonged LPS-induced inflammation caused acute IR, followed by long-lasting tissue-specific dysfunctions of lipid-, glucose-, and insulin metabolism-related targets; this ultimately resulted in dyslipidemia but not whole-body IR. Endotoxemia in cats may provide a promising model to study the cross talk between metabolic and inflammatory responses in the development of adipose tissue dysfunction and IR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / physiopathology*
  • Animals
  • Cats
  • Endotoxemia / chemically induced
  • Endotoxemia / metabolism*
  • Gene Expression Regulation
  • Inflammation / chemically induced*
  • Insulin Resistance
  • Insulin-Secreting Cells
  • Lipid Metabolism / physiology*
  • Lipopolysaccharides
  • Lipoproteins / metabolism*
  • Male

Substances

  • Lipopolysaccharides
  • Lipoproteins