Estimation of Na\K - ATPase Enzyme Activity and Endogenous Digitalis in Patients with Diabetic Neuropathy

Abstract

Background: Among the most common complications of diabetes is diabetic neuropathy (DN). Diabetic neuropathy is a heterogeneous group of disorders, which involves a different part of somatic and autonomic nervous systems, with a gradual loss of neural conductivity. Some studies have shown that they reduce the activity of the Na/K ATPase, however, elevated levels of endogenous sodium pump inhibitor in diabetic individuals, including those with neuropathy. Changes in this transfer enzyme are believed to be due to several diabetes complications. Objective: The study had designed to evaluate the Na/K ATPase enzymatic activity in the erythrocyte-membrane among three groups. The first group had represented the patients with type 2 diabetes mellitus (DM2) and neuropathy. The second group is diabetics without neuropathy. The third group was a healthy subject. As well, the study had estimated the inhibitory activity of endogenous digitalis among patient groups. Furthermore, the aim of this research was to see whether there was a connection between red blood cell membrane Na-K ATPase activity and the medical facts of the analysis subjects. Design and Methods: One-hundred fifty subjects had enrolled in this case-control study; 80 patients complained of diabetic neuropathy of both sexes, the mean age 59.3 years with an age range of 40-81, 40 DM2 without neuropathy (53.9 years), (35 – 70), and 30 healthy controls (30 years, 25 to 45). Patients in the first group were selected carefully according to their clinical manifestations and the nerve conduction study results. The evaluations of both inhibitory activities of endogenous digitalis and Na/K ATPase had completed using a spectrophotometer. Enzyme activity had expressed in micrograms of phosphate concentration per grams of red cell ghost total protein concentration. Results: The mean enzyme activity of Na/K ATPase was significantly lower (p<0.001) in patients with diabetic neuropathy (381±17.9) compared with the diabetic group without neuropathy (498±22.9) and the normal controls (837±61.43). There was a significant inhibitory activity of endogenous digitals (17.87±2.15) in patients with DNP, compared with the diabetics without neuropathy (8.78±0.89) and healthy control (5.3±1.33). There was a significant association of enzyme activity with the following parameters: duration of diabetes, age, level of glycated hemoglobin and endogenous digitalis with the respective p-values (0.000, 0.000, 0.000 and 0.021). Gender showed no significant relationship with enzyme activity (p 0.43). Conclusions: In DM2 with neuropathy, hyperglycemia can much reduce the activity of erythrocyte Na/K ATPase. In addition, it may enhance the inhibitory activity of endogenous digitals. The timedependent increase in diabetic complications can be due to a strong association between diabetes duration and erythrocyte Na/K-ATPase activities.