Key result
Whole-body AT1R inhibition reduces atherosclerosis in mice, while proximal tubule-specific RAS manipulation has no effect.
Why the study?
Whole-body renin-angiotensin system manipulation affects atherosclerosis, but sex differences remain understudied and the specific tissue sites of action are unknown. Given high renal angiotensin concentrations, this study evaluated the role of proximal tubule cell renin-angiotensin system components in atherosclerosis.
Does manipulation of the renin-angiotensin system in renal proximal tubules alter atherosclerosis in hypercholesterolemic mice?
Does manipulation of the renin-angiotensin system in renal proximal tubules alter atherosclerosis in hypercholesterolemic mice?
While whole-body AT1 receptor inhibition reduces atherosclerosis in both sexes, specific manipulation of RAS components in renal proximal tubule cells does not alter atherosclerosis development in hypercholesterolemic mice.
AT1R inhibition reduces atherosclerosis independently of proximal tubules; leaves open systemic or other cell-specific mechanisms for targeted study.
Background and objective Whole body manipulation of the renin-angiotensin system (RAS) consistently exerts profound effects on experimental atherosclerosis development. A deficit in the literature has been a lack of attention to the effects of sex. Also, based on data with gene-deleted mice, the site of RAS activity that influences lesion formation is at an unknown distant location. Since angiotensin (AngII) concentrations are high in kidney and the major components of the RAS are present in renal proximal tubule cells (PTCs), this study evaluated the role of the RAS in PTCs in atherosclerosis development. Methods and results Mice with an LDL receptor −/− background were fed Western diet to induce hypercholesterolemia and atherosclerosis. We first demonstrated the role of AT1 receptor antagonism on atherosclerosis in both sexes. Losartan, an AngII type 1 (AT1) receptor blocker, had greater blood pressure-lowering effects in females than males, but equivalent effects between sexes in reducing atherosclerotic lesion size. To determine the roles of renal AT1a receptor and angiotensin-converting enzyme (ACE), either component was deleted in PTCs after weaning using a tamoxifen-inducible Cre expressed under the control of an Ndrg1 promoter. Despite profound deletion of AT1a receptor or ACE in PTCs, the absence of either protein did not influence development of atherosclerosis in either sex. Conversely, mice expressing human angiotensinogen and renin in PTCs or expressing human angiotensinogen in liver but human renin in PTCs did not change atherosclerotic lesion size in male mice. Conclusion Whole-body AT1R inhibition reduced atherosclerosis equivalently in both male and female mice; however, PTC-specific manipulation of the RAS components had no effects on hypercholesterolemia-induced atherosclerosis.
No takes yet. Share an insight, caveat, or question.
Kukida et al. (2023) studied Hypercholesterolemia-induced atherosclerosis. Proximal tubule cell-specific manipulation of RAS components (AT1aR or ACE deletion, or human AGT/renin expression) vs. Wild-type littermates was evaluated on Percent atherosclerotic lesion area. Whole-body AT1R inhibition reduced atherosclerosis equivalently in male and female mice, but proximal tubule cell-specific manipulation of renin-angiotensin system components had no effect.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: