The Influence Of Homocysteine To Diabetic Microangopathy And Its Possible Mechanism

1. Changes of the plasma homocysteine and its risk factors in type 2 diabetes with microangopathyObjective: To study the possibility of homocysteine (Hey) as a risk factor for microangopathy in type 2 diabetes (DMAP) and its risk factors. Methods: Plasma Hey levels were measured by Fluorescence Polarization Immunoassay (FPIA) in 157 diabetics with or without microangopathy and 28 normal subjects. Plasma folic acids, vitamin B,2, BMI, HbAlc, FBG, PEG, BUN, Cr, Ch and TG levels were measured. The mutations of the C667T transition of MTHFR and the A66G of MSR were determined by PCR-RFLP. Results: The patients with DMAP had higher Hey levels and higher prevalence of hyperhomocysteinemia (HHcy) than normal group, while diabetics with nephropathy higher than those without this complication. The Hey levels in type 2 diabetes were positively related to BB genetype of MTHFR, BMI, HbAlc, FBG, PBG and metformin treatment, and were negtiyely related to plasma folate and vitamin 612 levels. By stepwise regression analysis, vitamin B)2, HbAlc, BB genetype of MTHFR and plasma folate level were the independent factors for plasma Hey level in type 2 diabetes.2. The abnormal reaction to Post Methionine Loading test in type 2 diabetes withor without diabetic retinopathyObjective: To investgate the reaction of type 2 diabetes with retinopathy (DR) or without (NDC) to post methionine loading (PML) test, the significance to identify hyperhomo- cysteinemia (Hhcy) by PML test. Methods: Plasma Homocysteine (Hey) levels were measured by Fluorescence Polarization Immunoassay (FPIA) before (Fhcy) and 4h after PML (Phcy) in 32 diabetes with or without retinopathy and 28 normal subjects (CON). Plasma folic acids and vitamin B)2 levels were measured with radioimmunoassay method. The mutations of the C667T transition of MTHFR were determined by PCR-RFLP. BMI, HbAlc, FBG, PBG, BUN, Cr, Ch and TG were also detected. Results : The BMI, HbAlc, FBG and PBG levels in DM group were higher than those in CON group. The Fhcy level in DR and NDC group were 13.87umol/L and 11.59umol/L respectively, higher than 8.85umol/L of CON group kdF．wBk 半压进扩学戊 博士学位论文(P<0.01). The Phcy (37.34umol/L), difference between Fhcy and Phcy (Dhcy) (24.36umol/L) and the number of BB genetype of MTHFR (52.94%) in DR group were higher than that in CON group (22.65umol/L, 15.07umol and 17.96%) and higher than that in NDC group (25.03|amol/L, 14.26umol/L and 13.33%) (PO.05). Nine patients had Hhcy by Fhcy criterion and the number was 15 by Phcy criterion after PML test. And the prevalence of Hhcy in DR group was higher than that in NDC group, both of them were higher than that in CON group ( PO.001 ) .3. The effect of homocysteine on the diabetic nephropathy of kkay mice and itspossible mechanismObjective: To study the effect of homocysteine on the diabetic nephropathy of type 2 diabetes and its possible mechanism. Methods: Twenty-four Kkay mice were divided into three groups, 8 in each: diabetes group (KA), methionine-diet group (KB), and Folate and vitamin 812 treatment group (KC). C57B1/6 mice were used as normal control (C57). Four months After being treated with three different diets, one of the KA and two of the KB group were died, and the leaving mice were sacrificed and their serum homocysteine, folate and vitamin 812 were assayed by Fluorescence Polarization Irnmunoassay. The renal pathological changes were examined by periodic acid schiff (PAS) method and periodic acid-silver methenamine (PASM), and also electron microscope; The expression of matrix metallporoteinase-9 (MMP-9) protein or mRNA was detected by immunohistochemical staining or RT-PCR method. Results: Kkay mice had different levels of diabetic nephropathy evidenced by morphological changes. It was showed that induction of hyperhomocysteinemia in Kkay mice (KB) by a diet enriched in methionine aggravated the severity of diabetic nephropathy and enhanced the expression of MMP-9 protein and mRNA levels in the glomer...