The Effect Of Reduced β₂-glycoprotein I On Diabetic Cardiovascular Matrix Metalloproteinases And Tissue Inhibitor Matrix Metalloproteinases And Its Mechanism

Objective:1.Investigate the effects and related mechanisms of reduced β2GP Ⅰ on MMP2 (Matrix metalloproteinase 2), MMP9, TIMP-1 (Tissue inhibitor of matrix metalloproteinase-1), TIMP-2 of diabetic mouse’s heart and aorta.2.Retrospective analysis of reduced β2GP Ⅰ correlation with diabetes/coronary heart disease, and reduced β2GP Ⅰ forecast for the diagnosis of coronary heart disease.Methods:1.648-week-old female Bal b/c mice,16 mice were randomly selected as normal control group, and were given standard chow diet for 8 weeks. Other 48 Balb/c mice were given a high-sugar high-fat diet for 8 weeks. Then they were injected with 2% STZ (80mg/kg,twice). One week later, the mice whose blood glucose were more than 16.7 mmol/L became diabetic model. They were randomly divided into six groups (n=8), including single-dose 3 groups (tail vein injections once):β2GP Ⅰ group (20μg/lml PBS), reduced β2GP Ⅰ group (20μ g/lml PBS), diabetic control group (1ml PBS), fed three weeks;complex dose 3 groups (tail vein injections twice, in the 1st day and the 22nd day):β2GP Ⅰ group (20μ g/lml PBS/each), reduced β2GP Ⅰ group (20μg/lml PBS/each),diabetic control group (lml PBS/each), fed 6 weeks. Then they were monitored body weight and blood glucose weekly. Blood lipids were measured at the third weekend and the sixth weekend, then they were drawn aorta and heart. One part were used to Sudan Ⅳ staining for lipid deposition, HE and TIMP-1 immunohistochemical staining, the other part were used to geletin spectrum for the detection of MMP2, MMP9 activity, western blot and real time PCR detection of MMP2, MMP9 TIMP-1 and TIMP-2 mRNA and protein, then research p38MAPK signaling pathway change.2.We collected 200 diabetic patients from Metabolic Diseases Hospital of Tianjin Medical University,100 patients with coronary artery disease from Tianjin Chest Hospital, and a normal control group of 40 people. The β2GP Ⅰ, reduced β2GP Ⅰ in their serum were measured by Elisa. Their general condition (age, gender), duration of diabetes, HbAlc, blood lipids, ejection fraction, left ventricular end-diastolic volume, family history of diabetes, hypertension, cardiovascular disease were collected by case records. Analysis correlation between β2GP Ⅰ/reduced β2GP Ⅰ and these indicators. And trying to determine its optimal threshold of reduced β2GP1 for diagonosing cardiovascular disease.Results:1. No difference in body weight between the groups (P>0.05), blood glucose in diabetic mice was significantly higher than the control group (P <0.05).LDL-c levels in reduced β2GP I group was lower than that in diabetic group (P<0.05). Aortic lipid deposition in reduced β2GP I group was significantly less than diabetic control group (P<0.05). In the aorta and heart, the activity of MMP2 and MMP9 in the diabetic group was the strongest. Reduced β2GP I suppressed their activity, especially in complex dose group. In aorta section, reduced β2GP Ⅰ decreased MMP2/TIMP2 mRNA, protein and MMP9/TIMP1 protein compared with diabetic control. Reduced β2GP I down regulated p38MAPK mRNA expression, phosphorylated p38MAPK protein compared with diabetic control in complex-dose. In heart section, MMP2/TIMP2 mRNA, protein and MMP9/TIMP1 protein expression were lowest in reduced β2GP Ⅰ group in complex-dose. Reduced β2GP Ⅰ increased p38MAPK mRNA expression and phosphorylated p38MAPK protein levels compared with diabetic control.2. There are differences in β2GP I and reduced P2GP I among DM (diabetes mellitus), CHD (coronary heart disease), DM & CHD (diabetes and coronary heart disease), normal control (NC) groups. β2GP I in DM group and DM&CHD group were higher than that in CHD group and NC group (P <0.05). Reduced β2GP I in DM group was lower than that in NC group. Reduced β2GP I in CHD group was higher than that in NC group. Reduced β2GP I in DM & CHD group was lower than that in CHD group but higher than that in DM group (all P<0.05). In diabetic patients, reduced β2GP Ⅰ associated with coronary heart disease (r=0.453, P=0.001). In patients with DM & CHD, reduced β2GP Ⅰ associated with SBP (r=0.458), DBP (r=0.381), Hb (r=0.453), TG (r=0.337), TC (r=0.511), LDL-c (r=0.468), BMI (r= 0.345) (all P<0.05). Reduced β2GP I as diagnostic indicators of CHD, when the cut-off point was 9.52mg/L, the positive likelihood ratio was 9.51, it had a relative strong predictive value for the diagnosis of coronary artery disease.Conclusions:Reduced β2GP Ⅰ play a role in cardiovascular protection, inhibiting vascular lipid deposition and plaaue formation by reducing MMPs/TIMPs through regulating p38MAPK signaling pathway. Reduced β2GP Ⅰ decreased in diabetic patients, when combining coronary heart disease, reduced β2GP Ⅰ elevated. When reduced β2GP Ⅰ grow greater than 9.52 mg/L, there is a relative strong predictive value for the diagnosis of coronary artery disease.