A 4-week high salt diet in mice with vascular smooth muscle PPARγ impairment caused salt-sensitive hypertension due to impaired vasodilation, which was prevented by blocking NKCC2 function.
Does failure to vasodilate during salt loading cause salt-sensitive hypertension in a mouse model?
Primary vascular dysfunction characterized by failure to vasodilate during salt loading causes salt-sensitive hypertension via an NKCC2-dependent mechanism.
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.
Wu et al. (Fri,) conducted a other in Salt-sensitive hypertension. High salt diet (HSD) was evaluated on Development of salt-sensitive hypertension and vasodilation impairment. A 4-week high salt diet in mice with vascular smooth muscle PPARγ impairment caused salt-sensitive hypertension due to impaired vasodilation, which was prevented by blocking NKCC2 function.