Increased inflammation, oxidative stress and a reduction in antioxidant defense enzymes in perivascular adipose tissue contribute to vascular dysfunction in type 2 diabetes

Lara Azul; Adriana Leandro; Parastoo Boroumand; Amira Klip; Raquel Seiça; Cristina M Sena

doi:10.1016/j.freeradbiomed.2019.11.002

Increased inflammation, oxidative stress and a reduction in antioxidant defense enzymes in perivascular adipose tissue contribute to vascular dysfunction in type 2 diabetes

Free Radic Biol Med. 2020 Jan:146:264-274. doi: 10.1016/j.freeradbiomed.2019.11.002. Epub 2019 Nov 5.

Authors

Lara Azul¹, Adriana Leandro¹, Parastoo Boroumand², Amira Klip², Raquel Seiça¹, Cristina M Sena³

Affiliations

¹ Institute of Physiology, iCBR, Faculty of Medicine, University of Coimbra, Portugal.
² Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
³ Institute of Physiology, iCBR, Faculty of Medicine, University of Coimbra, Portugal. Electronic address: csena@ci.uc.pt.

PMID: 31698080
DOI: 10.1016/j.freeradbiomed.2019.11.002

Abstract

Background: Perivascular adipose tissue (PVAT) surrounds most large blood vessels and plays an important role in vascular homeostasis. The present study was conducted to investigate the contribution of PVAT to vascular dysfunction in a rat model of type 2 diabetes.

Material and methods: Several in vivo parameters such as lipid profile (total cholesterol and triglyceride systemic levels), fasting glucose levels, glucose tolerance and insulin sensitivity (through glucose and insulin tolerance tests, respectively) were determined in Goto-Kakizaki (GK) diabetic rats and compared with control Wistar rats. At the vascular level, endothelial dependent and independent relaxation and contraction studies were performed in aortic rings in the absence (PVAT-) or in the presence (PVAT+) of thoracic PVAT. We also evaluated vascular oxidative stress and performed western blots, PCR and immunohistochemistry analysis of cytokines and various enzymes in PVAT.

Results: Endothelium-dependent relaxation to acetylcholine, assessed by wire myography, was impaired in GK rats and improved by the antioxidant TEMPOL and by the TLR4 inhibitor, CLI-095 suggesting an increase in oxidative stress and inflammation. In addition, vascular superoxide and peroxynitrite production was increased in the vascular wall of diabetic rats, accompanied by reduced nitric oxide bioavailability. The presence of PVAT had an anticontractile effect in response to phenylephrine in Wistar rats that was lost in GK rats. Western blot and immunohistochemistry analysis revealed that PVAT phenotype shifts, under diabetic conditions, towards a proinflammatory (with increment in CRP, CCL2, CD36), pro-oxidant (increased levels of aldose reductase, and reduced levels of antioxidant deference enzymes) and vasoconstriction state.

Conclusion: Our data suggest that this rat model of type 2 diabetes is associated with perivascular adipose dysfunction that contributes to oxidative stress, inflammation and endothelial dysfunction.

Keywords: Inflammation; Oxidative stress; PVAT; Type 2 diabetes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adipose Tissue / metabolism
Animals
Antioxidants / metabolism
Diabetes Mellitus, Experimental* / metabolism
Diabetes Mellitus, Type 2* / metabolism
Inflammation / metabolism
Oxidative Stress
Rats
Rats, Wistar
Vasoconstriction

Substances

Antioxidants