A Narrative Review of the Renin-Angiotensin-Aldosterone System in the Placenta and Placental Bed of HIV Infected Women of African Ancestry with Preeclampsia

Biomarkers and point of care screening approaches for the management of preeclampsia

Preeclampsia is a multi-organ pregnancy complication, that is primarily detected when pregnant people have high blood pressure, and is confirmed by testing for the presence of protein in the urine. While more specific and accurate diagnostic and imaging tests are becoming available, they are still in the process of undergoing widespread regulatory adoption, and so are not yet the standard of care. Since biochemical processes are a precursor to the systemic progression of disease, we review some established, emerging, and promising biomarkers that are proposed to be associated with preeclampsia, and newly developed approaches for screening them at the point of care, to reduce the burden of the disease.

Differential expression of the angiotensin receptors (AT1, AT2, and AT4) in the placental bed of HIV-infected preeclamptic women of African ancestry

The Renin-Angiotensin-Aldosterone System (RAAS) is implicated in the pathophysiology of preeclampsia (PE). There is a paucity of data on uteroplacental angiotensin receptors AT1-2 and 4. We evaluated the immunoexpression of AT1R, AT2R, and AT4R within the placental bed of PE vs. normotensive (N) pregnancies stratified by HIV status. Placental bed (PB) biopsies (n = 180) were obtained from N and PE women. Both groups were stratified by HIV status and gestational age into early-and late onset-PE. Immuno-labeling of AT1R, AT2R, and AT4R was quantified using morphometric image analysis. Immunostaining of PB endothelial cells (EC) and smooth muscle cells of spiral arteries (VSMC) displayed an upregulation of AT1R expression compared to the N group (p < 0.0001). Downregulation of AT2R and AT4R expression was observed in PE vs. N group (p = 0.0042 and p < 0.0001), respectively. AT2R immunoexpression declined between HIV+ve and HIV-ve groups, while AT1R and AT4R displayed an increase. An increase in AT1R expression was noted in the EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. In contrast, AT2R and AT4R expression decreased in EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. We demonstrate a significant downregulation of AT2R and AT4R with a concomitant elevated AT1R immunoexpression within PB of HIV-infected PE women. In addition, a decline in AT2R and AT4R with an increase in AT1R immunoexpression in PE, EOPE, and LOPE vs. normotensive pregnancies, irrespective of HIV status. Thus highlighting differential immunoexpression of uteroplacental RAAS receptors based on pregnancy type, HIV status, and gestational age.

Regulation of the Placental Renin-Angiotensin-Aldosterone System in Early- and Late-Onset Preeclampsia

Preeclampsia (PE) is one of the most dangerous complications of pregnancy, characterized by hypertension, proteinuria, and symptoms of multiple organ failure, which are detected de novo after 20 weeks of pregnancy. The renin-angiotensin-aldosterone system (RAAS) is one of the first to recognize pregnancy and is an important regulator of blood pressure. The placenta has its own RAAS, the role of which in the development of PE is not fully understood. In this work, for the first time, we characterized the expression of RAAS components and miRNAs controlling it in the placenta at various times of PE manifestation. The data obtained will allow the development of a new strategy in the future for the search for therapeutic agents for patients suffering from PE and cardiovascular diseases.