Pressor response to angiotensin II is enhanced in aged mice and associated with inflammation, vasoconstriction and oxidative stress

Quynh Nhu Dinh, Grant R. Drummond, Barbara K. Kemp-Harper, Henry Diep, T. Michael De Silva, Hyun Ah Kim, Antony Vinh, Avril A B Robertson, Matthew A Cooper, Ashley Mansell, Sophocles Chrissobolis, Christopher G. Sobey

Research output: Contribution to journalArticleResearchpeer-review

20 Citations (Scopus)

Abstract

Aging is commonly associated with chronic low-grade inflammation and hypertension but it is unknown whether a cause-effect relationship exists between them. We compared the sensitivity of young adult (8-12 w) and aged (23-31 mo) male C57Bl6J mice to develop hypertension in response to a slow-pressor dose of angiotensin II (Ang II; 0.28 mg/kg/d; 28 d). In young mice, the pressor response to Ang II was gradual and increased to 142±8 mmHg over 28 d. However, in aged mice, Ang II promptly increased SBP and reached 155±12 mmHg by 28 d. Aging increased renal but not brain expression of Ang II receptors (At1ar and At2r) and elevated AT1R:AT2R expression ratio in mesenteric artery. Maximal contractile responses of mesenteric arteries to Ang II were enhanced in aged mice and were not affected by L-NAME, indomethacin or tempol. Mesenteric arteries and thoracic aortae from aged mice exhibited higher Nox2-dependent superoxide production. Despite having higher renal expression of Nlrp3, Casp-1 and Il-1β, Ang II-induced hypertension (SBP: 139±7 mmHg) was unaffected by co-infusion of the NLRP3 inflammasome inhibitor, MCC950 (10 mg/kg/d; SBP: 145±10 mmHg). Thus, increased vascular AT1R:AT2R expression, rather than NLRP3 inflammasome activation, may contribute to enhanced responses to Ang II in aging.

Original languageEnglish
Pages (from-to)1595-1605
Number of pages11
JournalAging
Volume9
Issue number6
DOIs
Publication statusPublished - 28 Jun 2017

Keywords

  • Aging
  • Angiotensin II
  • Hypertension
  • Inflammation
  • Oxidative stress
  • Vasoconstriction

Cite this