Failure to vasodilate in response to salt loading blunts renal blood flow and causes salt-sensitive hypertension. Issue 1 (19th May 2020)

• Record Type: Journal Article
• Authors: Wu, Jing; Agbor, Larry N; Fang, Shi; Mukohda, Masashi; Nair, Anand R; Nakagawa, Pablo; Sharma, Avika; Morgan, Donald A; Grobe, Justin L; Rahmouni, Kamal; Weiss, Robert M; McCormick, James A; Sigmund, Curt D
• Is Part Of: Cardiovascular research. Volume 117:Issue 1(2021)
• Page Start: 308
• Page End: 319
• Publication Date: 2020-05-19
• Subjects: Hypertension -- Salt -- Smooth muscle -- Renal function -- Vasodilation -- PPARγ; Cardiovascular system -- Diseases -- Periodicals; Cardiovascular system -- Periodicals; 616.1
• DOI: 10.1093/cvr/cvaa147
• Languages: English
• ISSNs: 0008-6363

Abstract

Abstract: Aims: Salt-sensitive (SS) hypertension is accompanied by impaired vasodilation in the systemic and renal circulation. However, the causal relationship between vascular dysfunction and salt-induced hypertension remains controversial. We sought to determine whether primary vascular dysfunction, characterized by a failure to vasodilate during salt loading, plays a causal role in the pathogenesis of SS hypertension. Methods and results: Mice selectively expressing a peroxisome proliferator-activated receptor γ dominant-negative mutation in vascular smooth muscle (S-P467L) exhibited progressive SS hypertension during a 4 week high salt diet (HSD). This was associated with severely impaired vasodilation in systemic and renal vessels. Salt-induced impairment of vasodilation occurred as early as 3 days after HSD, which preceded the onset of SS hypertension. Notably, the overt salt-induced hypertension in S-P467L mice was not driven by higher cardiac output, implying elevations in peripheral vascular resistance. In keeping with this, HSD-fed S-P467L mice exhibited decreased smooth muscle responsiveness to nitric oxide (NO) in systemic vessels. HSD-fed S-P467L mice also exhibited elevated albuminuria and a blunted increase in urinary NO metabolites which was associated with blunted renal blood flow and increased sodium retention mediated by a lack of HSD-induced suppression of NKCC2. Blocking NKCC2 function prevented the salt-induced increase in blood pressure in S-P467L mice. Conclusion: We conclude that failure to vasodilate in response to salt loading causes SS hypertension by restricting renal perfusion and reducing renal NO through a mechanism involving NKCC2 in a mouse model of vascular peroxisome proliferator-activated receptor γ impairment. Graphical Abstract: