The relationship between nuclear factor-erythrocyte-related factor 2 and antioxidant enzymes in the placenta of patients with gestational diabetes and the metabolism of umbilical cord endothelial cells.

The paper aimed to explore the relationship between nuclear factor erythroid 2 related factor 2 (Nrf2), antioxidant enzymes and the metabolism of umbilical cord endothelial cells in the placenta of patients with gestational diabetes (GDM). A total of 200 pregnant women who underwent an obstetric examination at the Municipal Maternity and Child Health Hospital from March 2018 to December 2019 were selected, with an average age of 30.91±3.24. According to the plasma glucose level and oral glucose tolerance test (OGTT), pregnant women were divided into a control group and an observation group. Blood samples were collected from these pregnant women, serum was removed, put into a centrifuge tube and stored in the refrigerator of the laboratory at - 80 °C. Placental tissue was collected for biochemical analysis. GSH level was detected by absorbance kit, and serum MDA content was detected by spectrophotometry. The expression levels of Heme oxygenase-1(HO-1), Nrf2, and NQO1 protein in placental tissue were analyzed by gel electrophoresis. Western blot analysis was used to detect the protein expression levels of Bach1 and Keap1 in endothelial cells. PCR real-time analysis was used to detect the expression of GSH and NQO1 mRNA. Results showed that the SOD and GSH levels in the serum of the observation group were lower than those of the control group (P<0.05). The protein expression levels of HO-1, Nrf2 and NQO1 in the observation group were higher than those in the control group (P<0.05). The GSH level of the HNE+ observation group was lower than that of the HNE+ control group before stimulation (P<0.05). 1.5 hours after the stimulation, the GSH levels of the two groups of cells were decreased. After 6 hours, the GSH levels of the two groups began to increase. The GSH level of HUVEC in the HNE+ observation group was lower than that of the HNE+ control group after 48 hours. The expression level of Bach1 protein in the HNE+ observation group was lower than that in the HNE+ control group (P<0.05). The expression level of Keap1 protein in the HNE+ observation group and HNE+ control group did not change (P>0.05). The expression levels of GSH and NQO1 mRNA in the HNE+Nrf2 silence group were lower than that in the Nrf2 silence group (P<0.05). The expression levels of GSH and NQO1 mRNA in the HNE+Nrf2 overexpression observation group were higher than those of the HNE+Nrf2 silence group (P<0.05). The apoptosis of trophoblast in the placenta of GDM patients was significantly decreased. The continuous lack of redox signals in fetal endothelial cells in patients with gestational diabetes can destroy the defense ability of cells in the uterus against oxidative stress. Nrf2 antioxidant defense pathway can provide therapeutic targets for reducing oxidative stress associated with diabetes and aging.

A novel method to detect autoantibodies against platelets in patients with immune thrombocytopenia.

BACKGROUND AND OBJECTIVES: To examine anti-platelet autoantibodies in patients with immune thrombocytopenia (ITP) not only provides solid evidence for diagnosis, and also helps to select an individualized strategy for the treatment. The aim of this study is to develop a novel cell-based assay to detect autoantibodies in ITP patients. METHODS/PATIENTS: The DNA sequences of human platelet membrane protein GPIbα, GPIbß, GP IX, GPIIb and GPIIIa subunits were obtained from NCBI database and synthesized. The synthetic fragments were ligated into pcDNA 3.3 and constructed the recombinant plasmids and transfected into Chinese hamster ovary (CHO) cells to establish cell lines stable expressing GPIb-IX and/or GPIIb/IIIa complexes. One hundred and two ITP patients with different anti-platelet autoantibodies, 57 patients with other kinds of autoimmune diseases and 104 healthy control were selected to examine sensitivity, specificity and accuracy of this method. RESULTS: CHO cells stable expressing GPIb-IX and/or GPIIb/IIIa proteins were established. The cells were fixed with 4% paraformaldehyde and stored at -80 ℃, more than 80% of the cells were still expressed target proteins after 180 days of storage. The concentrations of target antibody from 0.1 to 100 µg/ml were detectable by this method, and 10-50 µg/ml antibody binding to the CHO cells yielded higher distinguishable fluorescent intensities. Inter-assay and intra-assay coefficients of variation and receiver operating characteristic curve analysis showed that this method had relatively higher reproducibility and specificity. Compared with Flow Cytometric Immunobead Array, this method has relatively higher specificity (95.2%) and accuracy (90.8%) in detection of 102 ITP patients. CONCLUSION: A novel cell-based assay to detect autoantibodies in ITP patients is established, which appears to be a promising method to diagnose ITP.

All­trans retinoic acid reduces endothelin­1 expression and increases endothelial nitric oxide synthase phosphorylation in rabbits with atherosclerosis.

All-trans retinoic acid (ATRA) is a natural derivative of vitamin A that ameliorates atherosclerosis (AS) by regulating inflammatory factors. However, studies concerning the role of retinoic acid in artery endothelial function are rare. Therefore, the present study investigated its role in regulating the production of endothelin­1 (ET­1) and nitric oxide (NO) in rabbits with AS. The rabbits were randomly divided into 3 groups: The control group was administered an ordinary diet, while the high fat group and the ATRA drug intervention group were administered a high fat diet. After 12 weeks, the blood lipid levels of rabbits, the morphological structure of the arterial wall, the arterial intimal permeability, the activity of blood endothelial nitric oxide synthase (eNOS) and the level of plasma NO were investigated. Western blot analysis was used to detect the levels of ET­1, eNOS and eNOS phosphorylation at Ser­1177 (p­eNOS), and a radioimmunoassay was performed to detect the level of ET­1 in the plasma. It was identified that plaque formation was alleviated in the ATRA group compared with the high fat group, as revealed by hematoxylin and eosin and oil red O staining, and a similar trend was reflected in the immunofluorescence results for endothelial permeability. Western blotting demonstrated significantly decreased ET­1 expression levels in the arterial tissue of rabbits in the ATRA group compared with the high fat group, together with increased p­eNOS level (P<0.05), however, no difference was observed in the expression of eNOS (P>0.05). The trends observed for ET­1 and the activity of eNOS in plasma were similar to those for arterial tissue. Therefore, the present study demonstrated that ATRA may regulate the grade of AS by the reduction of ET­1 secretion and increased NO formation via increased phosphorylation of eNOS. ATRA provides a potential novel method for the treatment of atherosclerosis.

Protein kinase A determines platelet life span and survival by regulating apoptosis.

Apoptosis delimits platelet life span in the circulation and leads to storage lesion, which severely limits the shelf life of stored platelets. Moreover, accumulating evidence indicates that platelet apoptosis provoked by various pathological stimuli results in thrombocytopenia in many common diseases. However, little is known about how platelet apoptosis is initiated or regulated. Here, we show that PKA activity is markedly reduced in platelets aged in vitro, stored platelets, and platelets from patients with immune thrombocytopenia (ITP), diabetes, and bacterial infections. Inhibition or genetic ablation of PKA provoked intrinsic programmed platelet apoptosis in vitro and rapid platelet clearance in vivo. PKA inhibition resulted in dephosphorylation of the proapoptotic protein BAD at Ser155, resulting in sequestration of prosurvival protein BCL-XL in mitochondria and subsequent apoptosis. Notably, PKA activation protected platelets from apoptosis induced by storage or pathological stimuli and elevated peripheral platelet levels in normal mice and in a murine model of ITP. Therefore, these findings identify PKA as a homeostatic regulator of platelet apoptosis that determines platelet life span and survival. Furthermore, these results suggest that regulation of PKA activity represents a promising strategy for extending platelet shelf life and has profound implications for the treatment of platelet number-related diseases and disorders.

Platelet Integrin αIIbß3 Inhibitor Rescues Progression of Apoptosis in Human Platelets.

BACKGROUND Apoptosis plays an important role in the physiology of platelet function. We aimed to detect the effect of the platelet integrin αIIbß3 inhibitor, tirofiban, on apoptotic events, including mitochondrial inner-membrane potential (ΔΨm), phosphatidylserine (PS) exposure on platelet surface, and the generation of reactive oxygen species (ROS), when washed platelets were stimulated with thrombin. MATERIAL AND METHODS The study included washed platelets from healthy humans, divided into 4 groups: vehicle, and tirofiban (0.05 µg/ml, 0.25 µg/ml, and 0.5 µg/ml). Platelets were pretreated with vehicle or tirofiban and incubated at 37°C with agitation for 6 h and 24 h. Before thrombin addition, the vehicle group divided into 2 equal groups. Except one vehicle group, the other 4 groups were all stimulated with thrombin (1 U/ml) for 30 min at 37°C. Using flow cytometry, we studied the DYm and PS exposure on platelet surfaces, and the generation of ROS in platelets. RESULTS We observed that at the time of 6 h and 24 h, thrombin-stimulated vehicle platelets induced significant depo-larization of ΔΨm, higher PS exposure, and increased ROS production compared with the vehicle group (P<0.01). However, the tirofiban group had significantly more recovery of DYm, PS exposure, and ROS production compared with the thrombin group (P<0.01). CONCLUSIONS The platelet integrin αIIbß3 inhibitor, tirofiban, inhibits the depolarization of DYm, PS exposure on platelet surface, and ROS production when stimulated with thrombin. These results suggest that αIIbß3 inhibitor inhibits the initiation of apoptosis in platelets, showing a potential clinical application of tirofiban as an apoptosis inhibitor.