Functional Vascular Changes of the Kidney during Pregnancy in Animals: A Systematic Review and Meta-Analysis

Abstract

Renal vascular responses to pregnancy have frequently been studied, by investigating renal vascular resistance (RVR), renal flow, glomerular filtration rate (GFR), and renal artery responses to stimuli. Nonetheless, several questions remain: 1. Which vasodilator pathways are activated and to what extent do they affect RVR, renal flow and GFR across species, strains and gestational ages, 2. Are these changes dependent on renal artery adaptation, 3. At which cellular level does pregnancy affect the involved pathways? In an attempt to answer the questions raised, we performed a systematic review and meta-analysis on animal data. We included 37 studies (116 responses). At mid-gestation, RVR and GFR change to a similar degree across species and strains, accompanied by variable change in renal flow. At least in rats, changes depend on NO activation. At late gestation, changes in RVR, renal flow and GFR vary between species and strains. In rats, these changes are effectuated by sympathetic stimulation. Overall, renal artery responsiveness to stimuli is unaffected by pregnancy, except for Sprague Dawley rats in which pregnancy enhances renal artery vascular compliance and reduces renal artery myogenic reactivity. Our meta-analysis shows that: 1. Pregnancy changes RVR, renal flow and GFR dependent on NO-activation and sympathetic de-activation, but adjustments are different among species, strains and gestational ages; 2. These changes do not depend on adaptation of renal artery responsiveness; 3. It remains unknown at which cellular level pregnancy affects the pathways. Our meta-analysis suggests that renal changes during pregnancy in animals are qualitatively similar, even in comparison to humans, but quantitatively different.

Cardiac, renal and uterine hemodynamics changes throughout pregnancy in rats with a prolonged high fat diet from an early age

“…Numerous studies have examined the renal hemodynamic changes during pregnancy but there is a considerable heterogeneity in their findings that may be explained by the use of invasive methods at different gestational periods [1,22,23]. The changes of GFR and RBF in our rats with NFD ( Fig 5) are similar to that reported in women [6] during gestation.…”

Effects of Aloe arborescens Whole Plant Homogenate on Lipid Metabolism, Inflammatory Conditions and Liver Function of Dairy Cows during the Transition Period

“…An impairment of renal glomerular filtration rate has been reported in late gestation in many different species, including ruminants [60], and the massive utilization of amino acids for gluconeogenesis could concur in renal dysfunction of dairy cows during the late gestation [61]. Recent studies performed on monogastric models and humans found high levels of circulating pro-inflammatory cytokines (i.e., tumor necrosis factor alpha, interleukin 1) released during excessive lipid mobilization and uncontrolled inflammation to induce renal artery endothelial dysfunction [62][63][64], thus suggesting also high circulating NEFA and systemic inflammations occurring in dairy cows during TP to play a pivotal role in inducing renal dysfunctions in late gestation.…”

Preeclampsia: a gestational cardiorenal syndrome

“…The latter results from increased arterial and venous resistance by inhibition of endothelial NO‐mediated gestational vasodilatation, sympathetic sensitivity (van Drongelen et al . ) and relaxin (Conrad & Davison, ).…”

“…Disrupted endothelial function triggers further impairment of renal function via induction of podocyte dysfunction, with subsequent podocyturia (Craici et al 2014) and increased nephrin concentrations in serum and urine (Jung et al 2017), but also via thrombotic micro-angiopathy (Johnson & Nangaku, 2016). The latter results from increased arterial and venous resistance by inhibition of endothelial NO-mediated gestational vasodilatation, sympathetic sensitivity (van Drongelen et al 2014) and relaxin (Conrad & Davison, 2014).…”