PURPOSE: Obstructive sleep apnea and chronic obstructive pulmonary disease are independent risk factors of cardiovascular disease (CVD), and their coexistence is known as overlap syndrome (OS). Endothelial dysfunction is the initial stage of CVD; however, underlying mechanisms linking OS and CVD are not well understood. The aim of this study was to explore whether OS can lead to more severe inflammation and endothelial apoptosis by promoting endothelial dysfunction, and to assess the intervention effects of antioxidant tempol. MATERIALS AND METHODS: Male Wistar rats (n=66) were exposed to normal oxygen [normal control (NC) group], intermittent hypoxia (IH group), cigarette smoke (CH group), as well as cigarette smoke and IH (OS group). Tempol intervention was assessed in OS group treated with tempol (OST group) or NaCl (OSN group). After an 8-week challenge, lung tissues, serum, and fresh blood were harvested for analysis of endothelial markers and apoptosis. RESULTS: The levels of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, and apoptosis in circulating epithelial cells were the highest in OS group and the lowest in NC group. These levels were all greater in IH group than in CH group, and were lower in OST group than in OS and OSN groups (all p < 0.001). CONCLUSION: Synergistic effects of IH with cigarette smoke-induced emphysema produce a greater inflammatory status and endothelial apoptosis. OS-related inflammation and endothelial cell apoptosis may play important roles in promoting cardiovascular dysfunction, and antioxidant tempol could achieve a partial protective effect.
Animals ; Anoxia* ; Apoptosis* ; Cardiovascular Diseases ; Emphysema ; Endothelial Cells ; Epithelial Cells ; Humans ; Inflammation* ; Lung ; Male ; Oxygen ; Pulmonary Disease, Chronic Obstructive ; Rats* ; Rats, Wistar ; Risk Factors ; Sleep Apnea, Obstructive ; Smoke ; Tobacco Products

Objective To investigate the effect and mechanism of osteopontin(OPN)in hepatoma cell migration through galectin-3 binding protein(LGALS3BP).Methods Human hepatoma cell lines SMMC-7721,SMMC-P(stably transfected with empty eukaryotic expression vectors),and SMMC-OPN(stably transfected with the OPN gene)were cultured.mRNA expression levels of OPN and LGALS3BP were measured by RT-qPCR.Western blot assays were used to analyze the relative protein expression of OPN and LGALS3BP and PI3K/AKT pathway.Wound healing assays were performed to explore the cell migration ability.After transfection with LGALS3BP-targeting small interfering RNA(si-LGALS3BP)or negative control small RNA(si-NC)into SMMC-OPN cells,cell migration and relative expression of PI3K/AKT pathway-related proteins were assessed.Results Compared with SMMC-7721 and SMMC-P,the migratory ability of SMMC-OPN cells was significantly reinforced,and expression of LGALS3BP was obviously upregulated at both mRNA and protein levels.Moreover,relative expression of p-PI3K/PI3K and p-AKT/AKT proteins was significantly increased.Wound healing assays showed that the si-LGALS3BP obviously suppressed the migratory ability of SMMC-OPN cells.Furthermore,relative expression of p-PI3K/PI3K and p-AKT/AKT proteins in SMMC-OPN cells was significantly decreased after transfection of si-LGALS3BP.Conclusions OPN activates the PI3K/AKT pathway by upregulating LGALS3BP expression to promote hepatoma cell migration.

AIM:To establish a model of recurrent hypoglycemia(RH)in mice with type 1 diabetes mellitus(T1DM)and to investigate the expression and effects of glucagon-like peptide-1(GLP-1)in the intestines of the model mice.METHODS:The T1DM model was established by induction with streptozotocin.Starting from the 15th day of T1DM,the mice in RH group were injected intraperitoneally with short-acting insulin,experiencing 1 episode of hyperin-sulinemic hypoglycemia every 3 days over 5 episodes,to establish the RH model in T1DM mice.Body weight,blood glu-cose,and activity status of the mice were recorded.Enzyme-linked immunosorbent assay(ELISA)was used to measure plasma adrenaline,glucagon(GCG),GLP-1,and somatostatin(SST)levels after the fifth episode of hypoglycemia for 60 min.Immunofluorescence staining was utilized to detect the expression of intestinal GLP-1 and hormone secretions from pancreatic α and δ cells in each group.Western blot was employed to detect protein expressions of GLP-1,GLP-1 receptor(GLP-1R),and prohormone convertase 1/3(PC1/3)in the intestine.RESULTS:Blood glucose and body weight met the standards for T1DM mice.During the 5 episodes of hypoglycemia,blood glucose levels in the RH group dropped to(3.3±0.5)mmol/L for more than 60 min during each episode of hypoglycemia,along with levels of plasma adrenaline and gluca-gon and the behavioral changes of RH mice during hypoglycemia,which met the modeling criteria of RH and impaired hy-poglycemic counterregulation in diabetic mice.ELISA detection showed that the plasma adrenaline and GCG levels were lower in RH group than those in T1DM group(P<0.01),while the plasma active GLP-1 and SST levels in mice were sig-nificantly higher in RH group(P<0.01).Immunofluorescence analysis showed that intestinal GLP-1 expression and pan-creatic SST secretion increased in RH group(P<0.01),while GCG secretion decreased(P<0.01).Western blot analysis showed that the levels of intestinal active GLP-1 and GLP-1R in RH group were significantly higher than those in T1DM group(P<0.01).CONCLUSION:Recurrent hypoglycemia in T1DM mice leads to increased intestinal GLP-1 expres-sion and secretion,which is closely related to the formation or aggravation of impaired hypoglycemic counterregulation.