Steroid hormone bioavailability is controlled by the lymphatic system.

The steroid hormone progesterone accounts for immune tolerance in pregnancy. Enhanced progesterone metabolism to 6α-OH-pregnanolone occurs in complicated pregnancies such as in preeclampsia with preterm delivery or intrauterine growth restriction, and in cancer. As lymphatic endothelial cells (LECs) promote tumor immunity, we hypothesized that human LECs modify progesterone bioavailability. Primary human LECs and mice lymph nodes were incubated with progesterone and progesterone metabolism was analyzed by thin layer chromatography and liquid chromatography-mass spectrometry. Expression of steroidogenic enzymes, down-stream signal and steroid hormone receptors was assessed by Real-time PCR. The placental cell line HTR-8/SV neo was used as reference. The impact of the progesterone metabolites of interest was investigated on the immune system by fluorescence-activated cell sorting analysis. LECs metabolize progesterone to 6α-OH-pregnanolone and reactivate progesterone from a precursor. LECs highly express 17β-hydroxysteroid dehydrogenase 2 and are therefore antiandrogenic and antiestrogenic. LECs express several steroid hormone receptors and PIBF1. Progesterone and its metabolites reduced TNF-α and IFN-γ production in CD4+ and CD8+ T cells. LECs modify progesterone bioavailability and are a target of steroid hormones. Given the global area represented by LECs, they might have a critical immunomodulatory control in pregnancy and cancer

Effects of aldosterone on the human placenta: Insights from placental perfusion studies.

INTRODUCTION In pregnancy, aldosterone is linked to maternal plasma volume expansion, improved fetal and placental growth/angiogenesis and reduced maternal blood pressure. Aldosterone levels are low in women with pre-eclampsia. Given the placental growth properties of aldosterone in pregnancy, we hypothesised that increased aldosterone improves placental function ex vivo. We applied aldosterone in the dual human placenta perfusion model and analysed specific regulatory markers. METHODS A single cotyledon was perfused using a trimodal perfusion setup consisting of a control phase (CP; basic perfusion medium (BPM) alone) and two consecutive experimental phases (EP1/EP2; BPM supplemented with 1.5 x 10-9M and 1.5 x 10-7M aldosterone, respectively). CP and EP1/EP2 were conducted in closed circuits lasting 2 h each. Quality/time control perfusions using BPM alone were performed for 360 min to distinguish time-dependent effects from aldosterone-related effects. Perfusates were assessed for control parameters (pH/pO2/pCO2/glucose/lactate/creatinine/antipyrine). Maternal perfusates were analysed for placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), interleukin-10 (IL-10) and tumour necrosis factor-alpha (TNF-α) using ELISAs. mRNA expression of abovementioned factors was measured by qPCR in post-perfusion tissue. RESULTS Data from quality/time control perfusions indicated that TNF-α and IL-10 release continuously increased over time. Contrary, in the trimodal perfusion setup the application of aldosterone decreased TNF-α secretion (P < 0.05, EP1/EP2 vs CP, 120 min) and increased PlGF release (P < 0.05, EP1 vs CP, 90/120 min) into the maternal perfusates. mRNA expression followed similar trends, but did not reach significance. DISCUSSION Our ex vivo placental perfusion data suggest that increasing aldosterone promotes anti-inflammatory and pro-angiogenic factors, which could positively contribute to healthy pregnancy outcomes

Physiological and Molecular Responses to Altered Sodium Intake in Rat Pregnancy

In pregnancy, a high plasma volume maintains uteroplacental perfusion and prevents placental ischemia, a condition linked to elevated maternal blood pressure (BP). Reducing BP by increasing Na+ intake via plasma volume expansion appears contra‐ intuitive. We hypothesize that an appropriate Na+ intake in pregnancy reduces maternal BP and adapts the renin‐angiotensin system in a pregnancy‐specific manner.Methods and Results: BP was measured by implanted telemetry in Sprague‐ Dawley rats before and throughout pregnancy. Pregnant and nonpregnant animals received either a normal‐salt (0.4%; NS), high‐salt (8%; HS), or low‐salt (0.01%; LS) diet, or HS (days 1–14) followed by LS (days 14–20) diet (HS/LS). Before delivery (day 20), animals were euthanized and organs collected. Food, water, and Na+ intake were monitored in metabolic cages, and urinary creatinine and Na+ were analyzed. Na+ intake and retention increased in pregnancy (NS, LS), leading to a positive Na+ balance (NS, LS). BP was stable during LS, but reduced in HS conditions in pregnancy. The renin‐angiotensin system was adapted as expected. Activating cleavage of α‐ and γ‐subunits of the renal epithelial Na+ channel and expression of‐ full length medullary β‐subunits, accentuated further in all LS conditions, were upregulated in pregnancy.Conclusions: Pregnancy led to Na+ retention adapted to dietary changes. HS exposure paradoxically reduced BP. Na+ uptake while only modestly linked to the renin‐angiotensin system is enhanced in the presence of posttranslational renal epithelial Na+ channel modifications. This suggests (1) storage of Na+ in pregnancy upon HS exposure, bridging periods of LS availability; and (2) that potentially non–renin‐angiotensin–related mechanisms participate in ENaC activation and consecutive Na+ retention

No extra-adrenal aldosterone production in various human cell lines.

Extra-adrenal de-novo aldosterone (Aldo) production has been described inconsistently. Systematic data based upon state-of-the-art technology including validated controls are sparse. We hypothesized that aldosterone synthase (CYP11B2) expression and de-novo Aldo production are absent in non-adrenal human cell lines, either immortalized cell lines or commercially available primary cell lines, including peripheral blood mononuclear cells (PBMCs) of individuals without and with primary hyperaldosteronism (PA). CYP11B2-transfected COS-7 and endogenous CYP11B2 expressing adrenal H295R cells served as positive controls. Various well-characterized, purchased, immortalized (BeWo, HEK293, HTR-8/SVneo, JEG-3) and primary (HAEC, HLEC, HRGEC, HRMC, HUAEC, HUVEC, PBMC) cell lines as well as self-isolated PBMCs from PA patients (n=5) were incubated with the steroid hormone substrates progesterone, deoxycorticosterone, corticosterone or 18-OH-corticosterone with and without Ang II for 24h to assess CYP11B2 enzymatic activity. CYP11B2 expression was analyzed by Real-time PCR and liquid chromatography-mass spectrometry (LC-MS) was used to quantify Aldo production. Pronounced CYP11B2 mRNA expression and Aldo production were observed in both positive controls, which followed an incremental time course. Neither substrates alone nor co-incubation with Ang II significantly stimulated CYP11B2 expression or Aldo production in various immortalized and primary cell lines and PBMCs of PA patients. These results strongly support the absence of a relevant de-novo extra-adrenal Aldo production in non-adrenal cells including, blood mononuclear cells irrespective of the absence or presence of autonomous adrenal Aldo production