The renal baroreflex: A systematic review and meta-analysis in healthy and hypertensive animals

The renal baroreflex describes the dose-dependent relation between renal pressure and renin release. Former studies have approximated this relation through animal experiments, but the exact shape of the response curve and its alteration by hypertension remain unclear. Therefore, we conducted a systematic review and meta-analysis on the renal baroreflex in healthy and hypertensive animals. Studies retrieved from Pubmed and Embase were screened according to predefined criteria. Data regarding study design and outcome data were extracted, and risk of bias was assessed. Dose-response meta-analysis was conducted on the relationship between renal blood pressure and renin release. Subgroup analyses were conducted for species, sex, outcome units, and experimental setup. From 1508 studies, 55 were included in the systematic review, and 30 in the meta-analysis. Risk of bias was high in most studies. Our meta-analysis shows that in healthy animals, renin decreases linearly with increasing renal blood pressure, reaching a plateau above a threshold pressure of 93 ± 2 mmHg. In hypertensive animals, the linear slope is diminished, the threshold is comparable, and the plateau level is slightly decreased as compared to healthy animals. Despite some limitations, our findings suggest that high blood pressure in hypertensive animals blunts the renal baroreflex by resetting and suppression of the renin response to changes in blood pressure.