Blood vessels function in the uptake, transport, and delivery of gases and nutrients within the body. A key question is how the central lumen of blood vessels develops within a cord of vascular endothelial cells. Here, we demonstrate that sialic acids of apical glycoproteins localize to apposing endothelial cell surfaces and generate repelling electrostatic fields within an endothelial cell cord. Both in vitro and in vivo experiments show that the negative charge of sialic acids is required for the separation of endothelial cell surfaces and subsequent lumen formation. We also demonstrate that sulfate residues can substitute for sialic acids during lumen initiation. These results therefore reveal a key step in the creation of blood vessels, the most abundant conduits in the vertebrate body. Because negatively charged mucins and proteoglycans are often found on luminal cell surfaces, it is possible that electrostatic repulsion is a general principle also used to initiate lumen formation in other organs.

The effects of the red wine polyphenolic compounds (Provinol) on hypertension, left ventricular hypertrophy, myocardial fibrosis, and vascular remodeling were investigated after chronic inhibition of nitric oxide (NO) synthase by administration of N(G)-nitro-L-arginine methyl ester (L-NAME) to rats. Rats were divided into four groups: a control group, a group treated for 4 wk with L-NAME (40 mg x kg(-1) x day(-1)), and two groups treated with L-NAME followed by 3 wk of either spontaneous recovery or recovery with Provinol treatment (40 mg x kg(-1) x day(-1)). Administration of Provinol produced a greater readiness of the decrease in blood pressure than that in the spontaneous recovery group. Provinol significantly depressed myocardial fibrosis and expedited the decrease in aortic cross-sectional area, the increase in endothelium-dependent relaxation, and the decrease in contraction of the aorta. These effects of Provinol were associated with a greater increase of NO synthase activity in the left ventricle and the aorta. The present study provides evidence that Provinol accelerates the regression of blood pressure and improves structural and functional cardiovascular changes produced by chronic inhibition of NO synthesis.

An intact endothelial cell barrier maintains normal gas exchange in the lung, and inflammatory conditions result in barrier disruption that produces life-threatening hypoxemia. Activation of store-operated Ca2+ (SOC) entry increases the capillary filtration coefficient ( K f,c) in the isolated rat lung; however, activation of SOC entry does not promote permeability in cultured rat pulmonary microvascular endothelial cells. Therefore, current studies tested whether activation of SOC entry increases macro- and/or microvascular permeability in the intact rat lung circulation. Activation of SOC entry by the administration of thapsigargin induced perivascular edema in pre- and postcapillary vessels, with apparent sparing of the microcirculation as evaluated by light microscopy. Scanning and transmission electron microscopy revealed that the leak was due to gaps in vessels ≥ 100 μm, consistent with the idea that activation of SOC entry influences macrovascular but not microvascular endothelial cell shape. In contrast, ischemia and reperfusion induced microvascular endothelial cell disruption independent of Ca2+ entry, which similarly increased K f,c. These data suggest that 1) activation of SOC entry is sufficient to promote macrovascular barrier disruption and 2) unique mechanisms regulate pulmonary micro- and macrovascular endothelial barrier functions.

Context.— Perinatal death is an increasingly important problem as the COVID-19 pandemic continues, but the mechanism of death has been unclear. Objective.— To evaluate the role of the placenta in causing stillbirth and neonatal death following maternal infection with COVID-19 and confirmed placental positivity for SARS-CoV-2. Design.— Case-based retrospective clinico-pathological analysis by a multinational group of 44 perinatal specialists from 12 countries of placental and autopsy pathology findings from 64 stillborns and 4 neonatal deaths having placentas testing positive for SARS-CoV-2 following delivery to mothers with COVID-19. Results.— All 68 placentas had increased fibrin deposition and villous trophoblast necrosis and 66 had chronic histiocytic intervillositis, the three findings constituting SARS-CoV-2 placentitis. Sixty-three placentas had massive perivillous fibrin deposition. Severe destructive placental disease from SARS-CoV-2 placentitis averaged 77.7% tissue involvement. Other findings included multiple intervillous thrombi (37%; 25/68) and chronic villitis (32%; 22/68). The majority (19, 63%) of the 30 autopsies revealed no significant fetal abnormalities except for intrauterine hypoxia and asphyxia. Among all 68 cases, SARS-CoV-2 was detected from a body specimen in 16 of 28 cases tested, most frequently from nasopharyngeal swabs. Four autopsied stillborns had SARS-CoV-2 identified in internal organs. Conclusions.— The pathology abnormalities composing SARS-CoV-2 placentitis cause widespread and severe placental destruction resulting in placental malperfusion and insufficiency. In these cases, intrauterine and perinatal death likely results directly from placental insufficiency and fetal hypoxic-ischemic injury. There was no evidence that SARS-CoV-2 involvement of the fetus had a role in causing these deaths.

In this translational study, we showed, for the first time, the prognostic value of PD-L1 expression in TGCTs and our data imply that the PD-1/PD-L1 pathway could be a novel therapeutic target in TGCTs.

This study used an inexpensive and versatile environmental exposure system to test the hypothesis that hypoxia promoted free radical production in primary cultures of rat main pulmonary artery smooth muscle cells (PASMCs). Production of reactive species was detected by fluorescence microscopy with the probe 2', 7'-dichlorodihydrofluorescein, which is converted to the fluorescent dichlorofluorescein (DCF) in the presence of various oxidants. Flushing the airspace above the PASMC cultures with normoxic gas (20% O(2), 75% N(2), and 5% CO(2)) resulted in stable PO(2) values of approximately 150 Torr, whereas perfusion of the airspace with hypoxic gas (0% O(2), 95% N(2), and 5% CO(2) ) was associated with a reduction in PO(2) values to stable levels of approximately 25 Torr. Hypoxic PASMCs became increasingly fluorescent at approximately 500% above the normoxic baseline after 60 min. Hypoxia-induced DCF fluorescence was attenuated by the addition of the antioxidants dimethylthiourea and catalase. These findings show that PASMCs acutely exposed to hypoxia exhibit a marked increase in intracellular DCF fluorescence, suggestive of reactive oxygen or nitrogen species production.

High SII was associated with poor outcome in GCTs. Combination of PD-L1 positive TILs and SII could further refine prognosis in GCTs.

Our results provide evidence that Provinols partially prevents L-NAME-induced hypertension, cardiovascular remodeling and vascular dysfunction via the increase of NO-synthase activity and prevention of oxidative stress. Thus, the beneficial effects of plant polyphenols in prevention of hypertension may result from their complex influence on the NO balance in the cardiovascular system.