Placental tissues from nonhypertensive black patients demonstrate lower placental leptin expression compared to white patients independent of BMI

Abstract

Hypertensive disorders of pregnancy increases risk of maternal and fetal morbidity and mortality. In the US, clinical data indicates that black women are more likely to develop hypertensive pregnancy than white women for reasons largely unknown. The goal of this study was to determine if expression of factors associated with hypertensive pregnancies, in the absence of hypertension milieu, differed between placental tissues from black versus white patient deliveries. We hypothesized that placental tissues from black patient deliveries demonstrate increases in gene expression of these factors compared to white patient deliveries. We collected placentas at time of delivery from healthy, nonhypertensive black (n=13) and white (n=14) patients from AU Medical Center. Snap frozen tissue from maternal side of placenta was processed to isolate RNA, reverse transcriptase for cDNA generation and then subjected to digital droplet PCR analysis of known markers of preeclampsia: leptin (Lep), preproendothelin-1 (PPET1), endothelin converting enzyme-1 (ECE-1) and placental growth factor (PLGF). Data output was recorded for each expression in copies/ul. Body mass index (BMI) at delivery did not differ between black (32.0±2.1 kg/m2) and white patients (31.3±1.4). In addition, correlation analysis (Pearson’s Correlation Coeffcient) was performed for BMI vs expression of Lep, PPET1, ECE-1 and PLGF in all samples from black and white patients and no significant association was found (P>0.05, R2<0.5 for all comparisons). Comparisons of gene expression between white and black patients was performed by 2-tailed t test. Lep expression significantly decreased in black compared to white patient placenta (74±61 vs 590±173 copies/ul, *p<0.05). However, placental expressions of PPET1 (844±185 black vs 626±164 white, copies/ul), ECE-1 (327±117 black vs 626±164 white, copies/ul), and PLGF (305±80 black vs 217±39 white, copies/ul) did not significantly increase or decrease in black compared to white patients. Collectively, these data surprisingly indicate that in nonhypertensive pregnancies, black patients demonstrate lower leptin expression compared to white patients. However, endothelin-1 associated ECE-1 and PPET1 expressions do not increase in nonhypertensive black patient placenta compared to white. As leptin expression is characteristically elevated in hypertensive pregnancy, future studies will determine if placentas collected from hypertensive black and white pregnancies demonstrate a discrepant gene expression in genes associated with increased risk of hypertensive pregnancy. NIH grants 1R01HL169576, 4R00HL146948. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.