Short-term high-fat feeding induces islet macrophage infiltration and β-cell replication independently of insulin resistance in mice

David C. Woodland, Wei Liu, Jacky Leong, Mallory L. Sears, Ping Luo, Xiaojuan Chen

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Short-term high-fat consumption stimulates mouse islet β-cell replication through unknown mechanisms. Resident macrophages (MΦs) are capable of secreting various factors involved in islet development and tissue remodeling. We hypothesized that a short-term high-fat diet (HFD) promotes MΦ infiltration in pancreatic islets and that MΦs serve as a regulator of β-cell replication. To test these hypotheses and dissect mechanisms involved in HFD-induced β-cell replication, adult C57BL/6J mice were fed a HFD for 7 days with or without administration of clodronate-containing liposomes, an MΦ-depleting agent. Mouse body and epididymal fat pad weights, and nonfasting blood glucose and fasting serum insulin levels were measured, and pancreatic islet β-cell replication, oxidative stress, and MΦ infiltration were examined. Short-term HFD promoted an increase in body and epididymal fat pad weight and blood glucose levels, along with an increased fasting serum insulin concentration. β-Cell replication, islet MΦ infiltration, and the percentage of inducible NO synthase positive MΦs in the islets increased significantly in mice fed the HFD. Immunofluorescence staining for 8-oxo-2'-deoxyguanosine or activated caspase-3 revealed no significant induction of DNA damage or apoptosis, respectively. In addition, no change in stromal-derived factor 1-expressing cells was found induced by HFD. Despite continuous elevation of nonfasting blood glucose and fasting serum insulin levels, depletion of MΦs through treatments of clodronate abrogated HFD-induced β-cell replication. These findings demonstrated that HFD-induced MΦ infiltration is responsible for β-cell replication. This study suggests the existence of MΦ-mediated mechanisms in β-cell replication that are independent of insulin resistance.

Original languageEnglish (US)
Pages (from-to)E763-E771
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume311
Issue number4
DOIs
StatePublished - 2016
Externally publishedYes

Keywords

  • HFD
  • Macrophage
  • β-cell replication

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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