Comparison between the Effects of Intraperitoneal Injection of LDL and Intravenous Injection of LDL on Arterial Endothelial Cells Apoptosis

To observe the effect of oxidized low density lipoprotein (OxLDL) on arterial endothelial cells apoptosis in vivo, we established a model in which Sprague-Dawley rats were given intraperi-toneal and intravenous injection of unmodified LDL (8 mg/kg every day) via the tail vein. Seven days after the injection, the aortic endothelial cells specimens were prepared by an en face preparation of rat aorta. The apoptotic cells were identified and counted by in situ nick and labelling (TUNED method and light microscopy. The numbers of the apoptotic cells were 12. 52±4. 71/field in the in-traperitoneal injection control group, 11. 41±2. 94/field in the intravenous injection control group, 22. 98±8. 01/field in the intraperitoneal injection LDL group and 103. 8±11. 5/field in the intravenous injection LDL group, respectively. The difference was significant between injection LDL group and control (P<0. 01), and the difference was also significant between two LDL injection groups (P<0. 01). These findings suggest that injection of LDL can induce apoptosis in arterial endothelial cells and the effect is especially significant with intravenous injection LDL. After injection, oxidative modification of LDL may occur in local arteries and causes injury to the endothelial cells.

Effects of L-Tetrahydropalmatine on NOSⅢ Gene Expression in Hypoxia and Cultured Porcine Cerebral Arterial Endothelial Cells during Reoxygenation

To investigate the expression of NOSⅢ mRNA and protein in cultured porcine cerebral arterial endothelial cells (CAEC) during hypoxia and reoxygenation and the effects of L-Tetrahydropalmatine (L-THP) on the gene expression of NOSⅢ in CAEC during hypoxia and reoxygenation. The cultured CAEC were divided into 5 groups: control, hypoxia, hypoxia+reoxygenation, hypoxia+L-THP and reoxygenation+L-THP groups. NOSⅢ mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR). Immunocytochemistry was used to detect the level of NOSⅢ protein. The expression of NOSⅢ mRNA and protein were increased when CAEC were exposed to hypoxia for 1 h, and significantly decreased during reoxygenation 2, 6 and 12 h after 1-h of hypoxia. L-THP from 10 -8 mol/L to 10 -3 mol/L could inhibit the up-regulation of NOSⅢ gene expression during hypoxia and down-regulation of NOSⅢ gene expression during reoxygenation.

Adult-repopulating lymphoid potential of yolk sac blood vessels is not confined to arterial endothelial cells

During embryogenesis,hematopoietic stem progenitor cells(HSPCs)are believed to be derived from hemogenic endothelial cells(HECs).Moreover,arterial feature is proposed to be a prerequisite for HECs to generate HSPCs with lymphoid potential.Although the molecular basis of hematopoietic stem cell-competent HECs has been delicately elucidated within the embryo proper,the functional and molecular characteristics of HECs in the extraembryonic yolk sac(YS)remain largely unresolved.In this study,we initially identified six molecularly different endothelial populations in the midgestational YS through integrated analysis of several single-cell RNA sequencing(scRNA-seq)datasets and validated the arterial vasculature distribution of Gja5+ECs using a Gja5-EGFP reporter mouse model.Further,we explored the hemogenic potential of different EC populations based on their Gja5-EGFP and CD44 expression levels.The hemogenic potential was ubiquitously detected in spatiotemporally different vascular beds on embryonic days(E)8.5–E9.5 and gradually concentrated in CD44-positive ECs from E10.0.Unexpectedly,B-lymphoid potential was detected in the YS ECs as early as E8.5 regardless of their arterial features.Furthermore,the capacity for generating hematopoietic progenitors with in vivo lymphoid potential was found in nonarterial as well as arterial YS ECs on E10.0–E10.5.Importantly,the distinct identities of E10.0–E10.5 HECs between YS and intraembryonic caudal region were revealed by further scRNA-seq analysis.Cumulatively,these findings extend our knowledge regarding the hemogenic potential of ECs from anatomically and molecularly different vascular beds,providing a theoretical basis for better understanding the sources of HSPCs during mammalian development.

Bench to beside:the imbalance of mutual regulation of homocysteine and hydrogen sulfide in congenital heart disease related pulmonary arterial hypertension

Background To determine the imbalance of mutual regulation of homocysteine and hydrogen sulfide(H;S)in congenital heart disease(CHD)-related pulmonary arterial hypertension(PAH)among pediatric patients,and explore possible mechanisms.Methodology and Principal Findings:In this study,we regulated homocysteine concentrations to observe the relations between homocysteine and H;S.Cell viability and activity of metabolic enzymes were determined.Cytological experiments demonstrated that exogenous or endogenous H;S both had protective effects on HPAECs and can inhibit homocysteine-induced apoptosis.The possible mechanisms were correlated with GRP78 and CHOP expressions of endoplasmic reticulum stress pathway.In addtion,we found that homocysteine and H;S were in a dynamic change,which was related to the homocysteine concentration.When the homocysteine concentrations were low(≤30μmol/L),the protective effects of H;S can resist the homocysteine-induced damage effects.However,the cytological results were different from the clinical data.Our clinical study had showed that the levels of homocysteine were higher,the levels of H;S and the OD values of cystathionine gamma-lyase(CSE)were lower in the PAH group.All the CHD-PAH patients had low homocysteine(≤30μmol/L)concentrations still lead to PAH because of decreased the protective effects of H;S due to the decreased activity of CSE.Conclusion:Homocysteine and H;S both take part in the development of CHD-PAH.Hyperhomocysteinemia may be the pathogenic factor,while H;S is the protective factor.The mutual dynamic regulations are related to the homocysteine concentration.The clinical trials and cytological experiment results have great implications for clinical practice.For patients with PAH,not only the damage of homocysteine to endothelial cells,but also we should pay attention to the decreased protection of H;S and activity of metabolic enzymes.