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Maternal separation-induced increases in vascular stiffness are independent of circulating angiotensinogen levels.

Authors
  • Mahanes, Timothy M1
  • Murphy, Margaret O1
  • Ouyang, An2
  • Yiannikouris, Frederique B1
  • Fleenor, Bradley S3
  • Loria, Analia S1
  • 1 Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky.
  • 2 Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
  • 3 School of Kinesiology, Ball State University, Muncie, Indiana. , (India)
Type
Published Article
Journal
Journal of Applied Physiology
Publisher
American Physiological Society
Publication Date
Jul 01, 2020
Volume
129
Issue
1
Pages
58–65
Identifiers
DOI: 10.1152/japplphysiol.00703.2019
PMID: 32407243
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

The renin-angiotensin system (RAS) precursor angiotensinogen (AGT) has been implicated in the functional and mechanical alterations of the vascular wall in response to high-fat diet (HFD). Previously, we showed that HFD exacerbates angiotensin II-induced constriction in isolated aortic rings from male rats exposed to maternal separation (MatSep), a model of early-life stress. Thus, the aim of this study was to investigate whether MatSep increases AGT secretion promoting vascular stiffness in rats fed a HFD. Male Wistar-Kyoto MatSep offspring were separated (3 h/day, postnatal days 2-14), and undisturbed littermates were used as controls. At weaning, rats were fed for 17 wk a normal diet (ND) or a HFD, 18% or 60% kcal from fat, respectively. In plasma, there was a main effect of MatSep reducing AGT concentration (P < 0.05) but no effect due to diet. In urine, ND-fed MatSep rats displayed higher AGT concentrations that were further increased by HFD (P < 0.05 vs. control). AGT mRNA abundance and protein expression were increased in adipose tissue from HFD-fed MatSep rats compared with control rats (P < 0.05). No significant differences in liver and kidney AGT levels were found between groups. In addition, MatSep augmented vascular stiffness assessed on freshly isolated aortic rings from ND-fed rats (P < 0.05), yet HFD did not worsen vascular stiffness in either MatSep or control rats. There was no correlation between plasma AGT and vascular stiffness in ND-fed rats; however, this relationship was negative in HFD-fed MatSep rats only (P < 0.05). Therefore, this study shows that MatSep-induced increases in vascular stiffness are independent of diet or plasma AGT.NEW & NOTEWORTHY This study demonstrates that there was no correlation between circulating levels of angiotensinogen (AGT) and the development of vascular stiffness in rats exposed to early-life stress and fed a normal diet. This study also shows that early-life stress-induced hypersensitive vascular contractility to angiotensin II in rats fed a high-fat diet is independent of circulating levels of AGT and occurs without further progression of vascular stiffness. Our data show that early-life stress primes the adipose tissue to secrete AGT in a sex- and species-independent fashion.

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