Role of C-peptide and NA[+], K[+] atpase in the pathology of diabetic micro-vascular complications

ABSTRACT

The purpose of this study is aiming to find out the correlation between erythrocytes membrane Na[+], K[+] ATPase activity, duration of diabetes, C-peptide level, hyperglycemic control and micro-vascular complications. This study was carried out on the following groups [Group I control group] included [n = 10] normal healthy subjects, [Group II] included [n = 30] diabetic patients without complications, 10 of these patients were insulin dependent diabetics [IDD], 10 were non-insulin dependent diabetics [NIDD] treated with insulin and 10 were non-insulin dependent diabetics [NIDD] treated with oral hypoglycemic drugs, [Group III] [n = 30] diabetic patients with neuropathy, 10 of these patients were insulin dependent diabetics [IDD], 10 were non-insulin dependent diabetics [NIDD] treated with insulin and 10 were non-insulin dependent diabetics [NIDD] treated with oral hypoglycemic drugs, [Group IV] [n = 30] diabetic patients with nephropathy, 10 of these patients were insulin dependent diabetics [IDD], 10 were non-insulin dependent diabetics [NIDD] treated with insulin and 10 were non-insulin dependent diabetics [NIDD] treated with oral hypoglycemic drugs. Beside careful history taking, full clinical examination and routine investigations, all the studied groups were subjected to the following estimations, fasting blood glucose level, Glycosylated Hb level, Na[+] K[+] ATPase activity and serum C-peptide level. The mean values of the duration of diagnosis of diabetes were significantly higher in diabetics with complications [neuropathy and nephropathy] when compared to the diabetics without complications [P < 0.001] but no significant differences were present when diabetics with complications [neuropathy and nephropathy] were compared with each other [P > 0.05]. The mean values of the fasting blood glucose level were significantly higher in all diabetic groups when compared to the control group [P < 0.001] but no significant differences were present when diabetic groups compared with each other [P > 0.05]. The mean values of glycosylated hemoglobin levels were significantly higher in all diabetic groups when compared to the control group [P < 0.001] but there were no significant differences when diabetic groups compared with each other [P < 0.05]. The mean values of C-peptide levels were significantly lower in all diabetic groups when compared to the control group [P < 0.001], but no significant differences when diabetic groups compared with each other [P > 0.05]. The mean values of erythrocytes membrane Na[+], K[+] ATPase activity were significantly lower in IDD patients and NIDD patients with insulin therapy of all groups when compared with control group [P < 0.001] and it were significantly lower in NIDD patients with oral hypoglycemic therapy of complicated groups [neuropathy and nephropathy] when compared with control group [P < 0.01], but there were no significant difference between NIDD patients with oral hypoglycemic therapy of non-complicated group and control group [P > 0.05]. Also, It was found that the activity was significantly lower in diabetics with neuropathy and nephropathy when compared with diabetics without complications [P < 0.001], but no significant differences were present between diabetics with nephropathy and diabetics with neuropathy when compared with each other [P > 0.05], there is no significant correlation between Na[+], K[+] ATPase with duration, fasting blood glucose and glycosylated hemoglobin, but, there was sign positive correlation between Na[+], K[+] ATPase and C-peptide. Also, non significant correlation was present between C-peptide with duration, fasting blood glucose and glycosylated hemoglobin. Decrease in erythrocytes membrane Na[+], K[+] ATPase activity in diabetic patients occurs when serum C-peptide level is low, these two factors have a role in the development of diabetic complications, and there is no relation with duration of diabetes or hyperglycemic control. C-peptide and insulin stimulate the activity of Na[+], K[+] ATPase, but there is still strong argument for the physiological role of C-peptide in humans. This finding needs to be confirmed by more studies on patients with diabetes to establish if C-Peptide together with insulin could be beneficial in restoring Na[+], K[+] ATPase activity and improvement of diabetic complications