Substitution of a Plant-Based Diet Early in Pregnancy Improves Renal Function and Reduces Renal Inflammation in Preeclamptic Dahl Salt-Sensitive Rats

Preeclampsia (PE), pregnancy-induced hypertension and end organ damage, is associated with renal dysfunction and immune cell overactivation. Environmental factors, such as diet, have been shown to impact the risk of PE suggesting that diet can be a potential therapeutic target. Our group has demonstrated that dietary protein source impacts pregnancy phenotypes in the Dahl Salt-Sensitive rat. Dahl SS rats maintained on a purified 0.4% NaCl casein-based (C) diet develop a preeclamptic phenotype whereas SS rats maintained on a plant-based diet (WG) are protected. To determine if dietary substitution at conception can be utilized as a therapeutic, we tested the hypothesis that substituting SS rats to a plant-based diet at conception would improve renal function, attenuate pregnancy-induced renal damage, and reduce renal inflammation. To test this hypothesis, SS rats were either maintained on the casein-based diet throughout pregnancy (C->C) or switched to a wheat gluten-based diet at conception (C->WG). These purified diets are identical except the protein source. Glomerular filtration rate (GFR) was measured transdermally using FITC-sinistrin clearance at baseline (BL) and late pregnancy (LP, Gestational day 20) time points as well as urinary protein excretion rates to assess renal damage. Prior to pregnancy, there was no difference in BL GFRs among the groups (2.7±0.2 vs 2.5±0.1ml/min/100g BW, ns, n=7-8/group) or protein excretion rates (186±30 vs 190±18, ns, n=7-8/group). At LP, renal function was significantly different between the groups with the C->C group remaining unchanged while the C→WG group had a significant increase in GFR (2.8±0.1 vs 3.2±0.1 ml/min/100g BW, p< 0.05, C->C vs C->WG, n=7-8/group). When looking at the change in GFR between LP and BL, there was a significant rise in GFR in the C->WG group compared to the controls (0.07 vs 0.82 ml/min/100g BW, p< 0.01). Despite this improvement in renal function, protein excretion rate was only marginally improved by placing rats on a WG diet at conception compared to the control group (318±38 vs 292±21, p>0.05, n=7-8/group). After measuring GFR, immune cells were isolated from blood and kidneys at GD20. There was no difference in the numbers of circulating immune cells between the groups. In contrast, the C->WG group had significantly fewer renal CD45+ immune cells compared to the C->C group (~3.5-fold reduction), and this reduction was observed across all immune subsets. The data demonstrates that dietary protein source at conception may significantly influence renal adaptations and immune responses during pregnancy in Dahl SS rats. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.