[Maternal endothelial function in the course of pregnancy and postpartum - ultrasound-based longitudinal assessment using flow-mediated dilatation (FMD)]. / Maternale Endothelfunktion in Schwangerschaft und Wochenbett - ultraschallgestützte longitudinale Erfassung mittels Flow Mediated Dilatation (FMD).

PURPOSE: NO-triggered vasodilatation decreases peripheral vascular resistance in pregnancy. Using a noninvasive ultrasound technique, flow-mediated vasodilatation can be quantified. We used this technique to detect changes in endothelial function during pregnancy and postpartum. MATERIALS AND METHODS: In a prospective longitudinal study 16 healthy pregnant women were assessed for flow-mediated dilatation of the brachial artery during pregnancy (first trimester T 1 < 14th gestational week, second trimester T 2 ≥ 14th - 27th gestational week, third trimester T 3 ≥  28th gestational week) and postpartum (> 6 weeks postpartum). As a control group, flow-mediated dilatation was determined in 19 healthy non-pregnant women. RESULTS: Flow-mediated dilatation (%) increased significantly in normal human pregnancy from the first trimester (T1 8.0 ± 5.58 vs. T 2 15.2 ± 5.19, p < 0.003) to the second trimester and reached its maximum in mid-trimester. Towards the end of pregnancy, flow-mediated dilatation decreased significantly (T2 vs. T 3 9.15 ± 3.61, p < 0.004). Mean values of flow-mediated dilatation are significantly higher during the second and third trimester of pregnancy compared to non-pregnant controls (T2 vs. NP 6.17 ± 4.39, p < 0.001; T 3 vs. NP, p < 0.047). Postpartum flow-mediated dilatation decreased to values of early pregnancy. CONCLUSION: During pregnancy maternal endothelial function shows an increase in flow-mediated dilatation and then reverts postpartum. Using ultrasound-based measurement of flow-mediated dilatation, these physiological changes in pregnancy can be reliably detected.

Decrease of global methylation improves significantly hepatic differentiation of Ad-MSCs: possible future application for urea detoxification.

Hepatocyte transplantation is considered to be an alternative to orthotopic liver transplantation. Cells can be used to bridge patients waiting for a donor organ, decrease mortality in acute liver failure, and support metabolic liver diseases. The limited availability of primary human hepatocytes for such applications has led to the generation of alternative hepatocyte-like cells from various adult stem or precursor cells. The aim of this study was to generate hepatocyte-like cells from adipose-derived mesenchymal stem cells (Ad-MSCs) for clinical applications, which are available "off the shelf." Epigenetic changes in hepatocyte-like cells were induced by 5-azacytidine, which, in combination with other supplements, leads to significantly improved metabolic and enzymatic activities compared to nontreated cells. Cells with sufficient hepatic features were generated with a four-step protocol: 5-azacytidine (step 1); epidermal growth factor (step 2); fibroblast growth factor-4, dexamethasone, insulin-transferrin-sodium-selenite, and nicotinamide (step 3); and hepatocyte growth factor, dexamethasone, insulin-transferrin-sodium-selenite, and nicotinamide (step 4). Generated differentiated cells had higher phase I (CYP1A1/2, CYP2E1, CYP2B6, CYP3A4) and phase II activities compared to the undifferentiated cells. A strong expression of CYP3A7 and a weak expression of 3A4, as well as the important detoxification markers α-fetoprotein and albumin, could also be detected at the mRNA level. Importantly, urea metabolism (basal, NH4-stimulated, NH4- and ornithine-stimulated) was comparable to freshly isolated human hepatocytes, and unlike cryopreserved human hepatocytes, this activity was maintained after 6 months of cryopreservation. These findings suggest that these cells may be suitable for clinical application, especially for treatment of urea cycle disorders.

Autologous serum improves yield and metabolic capacity of monocyte-derived hepatocyte-like cells: possible implication for cell transplantation.

Hepatocyte-transplantation is a therapeutic approach for diverse acute and chronic liver diseases. As availability of primary cells is limited, there is an increasing demand for hepatocyte-like cells (e.g., neohepatocytes generated from peripheral blood monocytes). The aim of this study was to evaluate the effects of six different human AB sera, fetal calf serum, or autologous serum on production of neohepatocytes. The yield and quality of neohepatocytes varied considerably depending on the different sera. Using autologous sera for the whole production process we constantly generated the highest amount of cells with the highest metabolic activity for phase I (e.g., CYP1A1/2, CYP3A4) and phase II enzymes (e.g., glutathione-S-transferase). Moreover, similar effects were seen examining glucose and urea metabolism. Especially, glucose-6-phosphatase and PAS staining showed distinct serum-dependent differences. The role of macrophage activation was investigated by measuring the secretion of TNF-α, TGF-ß, and RANKL, MMP activity, as well as mRNA levels of different interleukins in programmable cells of monocytic origin (PCMO). Our data clearly demonstrate that the use of autologous serum reduced initial macrophage activation in PCMOs and subsequently improved both yield and function of differentiated neohepatocytes. The autologous approach presented here might also be useful in other stem cell preparation processes where cell activation during generation shall be kept to a minimum.