Somatostatin is expressed and secreted by human adipose tissue upon infection and inflammation

J Clin Endocrinol Metab. 2004 Oct;89(10):4833-9. doi: 10.1210/jc.2004-0271.

Abstract

Somatostatin (SRIF) is a well-known neuroendocrine secretion product. SRIF expression and secretion are induced after inflammation in murine macrophages and in endotoxin-injected sheep and pigs. Because adipocytes have been demonstrated to produce numerous cytokines and peptide hormones, we investigated the expression of SRIF and its receptors (SSTR1-5) in human adipose tissue after inflammatory stimulation in vitro and in tissues from patients with septic disease.Preadipocyte-derived adipocytes, mesenchymal stem cell-derived adipocytes, and mature explanted adipocytes expressed SRIF-mRNA after endotoxin [lipopolysaccharide (LPS)] or IL-1beta treatments. LPS- and IL-1beta-mediated SRIF-mRNA induction was blocked by pretreatment with dexamethasone. Using cocultures and quantitative real-time PCR, we demonstrate adipocyte SRIF induction by secretion factors from activated peripheral blood mononuclear cell-derived macrophages. In contrast to basal adipocytes, SRIF protein was detected in culture supernatants of LPS-treated and of combined TNFalpha/IL-1beta/LPS-treated adipocytes. SRIF protein was visualized by immunohistochemistry in explanted minced adipose tissue after overnight incubation in culture medium supplemented with combined IL-1beta and LPS. In septic patients, expression of SRIF-mRNA and SRIF protein was found in visceral, but not in sc, adipose tissue. Adipocyte mRNA abundance of SSTR 1-5 was differentially regulated by inflammatory treatments.Thus, human visceral adipose tissue secretes SRIF during inflammation and sepsis and expresses several SSTRs. It is tempting to speculate that visceral adipose tissue-derived SRIF plays a modulatory role in the immunological and metabolic response to inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipocytes / cytology
  • Adipocytes / metabolism
  • Adipocytes / physiology
  • Adipose Tissue / physiology*
  • Adult
  • Aged
  • Cells, Cultured
  • Humans
  • Membrane Proteins
  • Middle Aged
  • RNA, Messenger / analysis
  • Receptors, Somatostatin / genetics
  • Sepsis / metabolism
  • Sepsis / physiopathology*
  • Somatostatin / genetics*
  • Somatostatin / metabolism*

Substances

  • Membrane Proteins
  • RNA, Messenger
  • Receptors, Somatostatin
  • somatostatin receptor 3
  • somatostatin receptor subtype-4
  • somatostatin receptor type 1
  • Somatostatin
  • somatostatin receptor 5
  • somatostatin receptor 2