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Failure to vasodilate in response to salt loading blunts renal blood flow and causes salt-sensitive hypertension
Journal article   Open access   Peer reviewed

Failure to vasodilate in response to salt loading blunts renal blood flow and causes salt-sensitive hypertension

Jing Wu, Larry N Agbor, Shi Fang, Masashi Mukohda, Anand R Nair, Pablo Nakagawa, Avika Sharma, Donald A Morgan, Justin L Grobe, Kamal Rahmouni, …
Cardiovascular research, Vol.117(1), pp.308-319
05/19/2020
DOI: 10.1093/cvr/cvaa147
PMID: 32428209
url
https://doi.org/10.1093/cvr/cvaa147View
Published (Version of record) Open Access

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.

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