Gene expression of klotho & antioxidative enzymes in peripheral blood mononuclear cells of essential hypertension patients in Indian population

BACKGROUND & OBJECTIVES: Oxidative stress is known to have a causal role in hypertension. Klotho has emerged as a novel anti-aging molecule to inhibit oxidative stress at cellular level. This study aimed at evaluating the gene expression of klotho and antioxidative enzymes, manganese superoxide dismutase (Mn-SOD) and catalase, in peripheral blood mononuclear cells of essential hypertensive patients as compared to normotensive healthy controls. METHODS: Ninety-nine newly diagnosed hypertensives and 103 age- and BMI-matched controls were recruited. The participants were non-diabetic and not on any medication. Soluble α-klotho levels were detected using enzyme-linked immunosorbent assay. Gene expression was evaluated by quantitative real-time polymerase chain reaction. RESULTS: Soluble α-klotho levels were significantly lower (27%, P=0.001) in patients as compared to controls. The trend remained same when compared against 44 out of 103 controls considered for gene expression analysis. Relative gene expression of klotho and catalase were 3-fold and 1.25-fold lower in patients as compared to controls, respectively. ΔCt value-based gene expression were also significantly lower for both genes (P=0.001). A decreasing but non-significant trend was observed for Mn-SOD gene expression. ΔCt value-based gene expression of catalase positively correlated with that of Mn-SOD in patient (rs=0.448) and control (rs=0.547) groups (P<0.001). In patients, the gene expression of Klotho positively correlated with that of catalase (rs=0.498, P=0.001), but not Mn-SOD (rs=0.155, P=0.126). INTERPRETATION & CONCLUSIONS: In the present study on newly diagnosed hypertensives, klotho and catalase gene expression were found to be significantly lower as compared to controls, indicating the role of oxidative stress in this patient group. In addition, a significant correlation between Klotho and catalase gene expression suggests a role for klotho in essential hypertension with respect to antioxidant defence.