Long-term treatment with acylated analogues of apelin-13 amide ameliorates diabetes and improves lipid profile of high-fat fed mice

PLoS One. 2018 Aug 29;13(8):e0202350. doi: 10.1371/journal.pone.0202350. eCollection 2018.

Abstract

Previous studies have shown that modified apelin analogues exhibited enzyme resistance in plasma and improved circulating half-life compared to apelin-13. This study investigated the antidiabetic effects of chronic administration of stable long acting fatty acid modified apelin analogues, namely, (Lys8GluPAL)apelin-13 amide and pGlu(Lys8GluPAL)apelin-13 amide, in high-fat fed obese-diabetic mice. Male NIH Swiss mice (groups n = 8) were maintained either on a high-fat diet (45% fat) from 8 to 28 weeks old, or control mice were fed a normal diet (10% fat). When diet induced obesity-diabetes was established after high-fat feeding, mice were injected i.p. once daily with apelin analogues, liraglutide (25 nmol/kg) or saline (controls). Administration of (Lys8GluPAL)apelin-13 amide and pGlu(Lys8GluPAL)apelin-13 amide for 28 days significantly reduced food intake and decreased body weight. Non-fasting glucose was reduced (p<0.01 to p<0.001) and plasma insulin concentrations increased (p<0.01 to p<0.001). This was accompanied by enhanced insulin responses (p<0.01 to p<0.001) and significant reductions in glucose excursion after oral (p<0.01) or i.p. (p<0.01) glucose challenges and feeding. Apelin analogues also significantly improved HbA1c (p<0.01), enhanced insulin sensitivity (p<0.01), reduced triglycerides (p<0.001), increased HDL-cholesterol (p<0.01) and decreased LDL-cholesterol (p<0.01), compared to high-fat fed saline treated control mice. Cholesterol levels were decreased (p<0.01) by pGlu(Lys8GluPAL)apelin-13 amide and both apelin treated groups showed improved bone mineral content, reduced fat deposits and increased plasma GLP-1. Daily treatment with liraglutide mirrored many of these changes (not on bone or adipose tissue), but unlike apelin analogues increased plasma amylase. Consumption of O2, production of CO2, respiratory exchange ratio and energy expenditure were improved by apelin analogues. These results indicate that long-term treatment with acylated analogues (Lys8GluPAL)apelin-13 amide and particularly pGlu(Lys8GluPAL)apelin-13 amide resulted in similar or enhanced therapeutic responses to liraglutide in high-fat fed mice. Fatty acid derived apelin analogues represent a new and exciting development in the treatment of obesity-diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acylation
  • Amides / chemistry
  • Amides / pharmacology
  • Amides / therapeutic use*
  • Animals
  • Anti-Obesity Agents / pharmacology*
  • Diabetes Mellitus, Experimental / blood
  • Diabetes Mellitus, Experimental / drug therapy*
  • Diet, High-Fat / adverse effects
  • Hypoglycemic Agents / pharmacology*
  • Intercellular Signaling Peptides and Proteins / chemistry
  • Intercellular Signaling Peptides and Proteins / pharmacology
  • Intercellular Signaling Peptides and Proteins / therapeutic use*
  • Lipids / blood
  • Male
  • Mice
  • Obesity / blood
  • Obesity / drug therapy*
  • Time Factors

Substances

  • Amides
  • Anti-Obesity Agents
  • Hypoglycemic Agents
  • Intercellular Signaling Peptides and Proteins
  • Lipids
  • apelin-13 peptide

Grants and funding

The Department for the Economy, Northern Ireland (https://www.nidirect.gov.uk/articles/department-economy-studentships, formerly DEL-NI) provided a PhD studentship to CH and FOH to perform this work. Invest-NI Proof of Concept funding (https://www.investni.com/support-for-business/proof-of-concept.html, PoC518) was secured by FOH and PRF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding was received for this study.