Association between erythrocyte Na+K+-ATPase activity and some blood lipids in type 1 diabetic patients from Lagos, Nigeria

Abstract

BackgroundAltered levels of erythrocyte Na+K+-ATPase, atherogenic and anti-atherogenic lipid metabolites have been implicated in diabetic complications but their pattern of interactions remains poorly understood.This study evaluated this relationship in Nigerian patients with Type 1 diabetes mellitus.MethodsA total of 34 consented Type 1 diabetic patients and age -matched 27 non-diabetic controls were enrolled. Fasting plasma levels of total cholesterol, triglycerides and HDL-cholesterol were determined spectrophotometrically and LDL-cholesterol estimated using Friedewald formula. Total protein content and Na+K+-ATPase activity were also determined spectrophotometrically from ghost erythrocyte membrane prepared by osmotic lysis.ResultsResults indicate significant (P < 0.05) reduction in Na+K+-ATPase activity in the Type 1 diabetic patients (0.38 ± 0.08 vs. 0.59 ± 0.07 uM Pi/mgprotein/h) compared to the control but with greater reduction in the diabetic subgroup with poor glycemic control (n = 20) and in whom cases of hypercholesterolemia (8.8%), hypertriglyceridemia (2.9%) and elevated LDL-cholesterol (5.9% each) were found. Correlation analyses further revealed significant (P < 0.05) inverse correlations [r = -(0.708-0.797] between all the atherogenic lipid metabolites measured and Na+K+-ATPase in this subgroup contrary to group with good glycemic control or non-diabetic subjects in which significant (P < 0.05) Na+K+-ATPase and HDL-C association were found (r = 0.427 - 0.489). The Na+K+-ATPase from the diabetic patients also exhibited increased sensitivity to digoxin and alterations in kinetic constants Vmax and Km determined by glycemic status of the patients.ConclusionIt can be concluded that poor glycemic control evokes greater reduction in erythrocyte Na+K+-ATPase activity and promote enzyme-blood atherogenic lipid relationships in Type 1 diabetic Nigerian patients.

Activities of Three Erythrocyte Enzymes of Hyperglycemic Rats (Rattus norvegicus) Treated with Allium sativa Extract.

“…In a different study using human participants, it was noted that there was compromised erythrocyte Na + /K + -ATPase activity in Type 1 diabetic patients from Lagos, Nigeria. [35] This finding was corroborated by another study in which a reduction of erythrocyte Na + / K + -ATPase activity in Type 2 diabetic patients with hyperkalemia was noted.…”

“…[34,35] Briefly, 10 mL of ice cold 5 mM Tris/0.1 mM Na 2 EDTA (pH = 7.6) were added to test tubes containing buffy coat free-packed erythrocytes of test and control rats to achieve osmotic lysis. The resulting membranes were centrifuged at 20,000 g for 20 min at 4 °C.…”

Biochemical changes in erythrocyte membrane in type 2 diabetes mellitus

“…[2,21] Alterations in membrane cholesterol:Phospholipid ratio (as observed in the present study Table 4) result in morphological abnormal erythrocytes with decreased life span. [2,22,23] Changes in lipid composition of RBC membrane resulting in impairment of RBC deformability may play a role in altered blood rheological pattern. [4,22,23] The increase in RBC membrane cholesterol in Diabetics (group-II and III) reflects serum cholesterol [4,2] [Tables 2 and 4].…”

“…[2,22,23] Changes in lipid composition of RBC membrane resulting in impairment of RBC deformability may play a role in altered blood rheological pattern. [4,22,23] The increase in RBC membrane cholesterol in Diabetics (group-II and III) reflects serum cholesterol [4,2] [Tables 2 and 4]. There is a relationship between RBC membrane and serum lipid composition in subjects with type 2 diabetes mellitus with and without complications.…”

Changes in Erythrocyte Membrane in Type-Ii Diabetes Mellitus with and without Dyslipidemia

“…Na + K + -ATPase has been reported as one of the membrane proteins affected structurally and functionally in diabetes mellitus. In Diabetes there is a conformational change in the structure of the enzyme due to glycation and oxidative stress hence reducing its activity [4,21] . Altered level of RBC membrane lipid ratio decreases activity of membrane protein [2,22].…”