Erythrocyte membrane transporters during human ageing: Modulatory role of tea catechins

Abstract

Ageing is associated with many physiological and cellular changes, many of which are due to alterations in the plasma membrane. The functions of membrane transporter proteins are crucial for the maintenance of ionic homeostasis between the extra- and intracellular environments. The aim of the present study was to determine the status of erythrocyte membrane transporters, specifically Ca(2+) -ATPases, Na(+) /K(+) -ATPases and the Na(+) /H(+) exchanger (NHE), during ageing in humans. Furthermore, because tea catechins have been reported to possess strong anti-oxidant potential, the study was extended to evaluate the effect of (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG) on these transporters as a function of human age. The study was performed on 97 normal healthy subjects (62 men, 35 women; 16-80 years old). To investigate the effects of tea catechins, subjects were divided into three groups: young (<40 years old; n = 34); middle-aged (40-60 years old; n = 32); and old (>60 years old; n = 31). Erythrocyte ghosts/cell suspension from each group were incubated with ECG, EGCG, EGC and EC (10 μmol/L) for 30 min at 37°C prior to assay. Ageing significantly increased NHE activity and decreased Ca(2+) -ATPase activity. There were no significant changes in Na(+) /K(+) -ATPase activity during the ageing process. (-)-Epigallocatechin-3-gallate, EGC, ECG and EC effectively mitigated the changes in membrane transporter activity in erythrocytes from all age groups; however, the effect was more pronounced in the old age group. We hypothesize that impairment in -bound transporters may be one of the possible mechanisms underlying the pathological events during ageing. A higher intake of catechin-rich food may provide some protection against age-dependent diseases.

Erythrocyte Deformability and Na,K-ATPase Activity in Various Pathophysiological Situations and Their Protection by Selected Nutritional Antioxidants in Humans

“…However, it has to be mentioned that data concerning aging are controversial. Some other studies have shown that in healthy individuals, the enzyme activity was not influenced by aging [ 48 , 49 , 69 ].…”

“…A study of erythrocytes from normal healthy subjects differing in age, showed that the above-mentioned tea catechin (EGCG) decreased the oxidation of membrane lipids throughout the range of human age with the highest effectivity in the group of oldest individuals [ 96 , 97 ]. Concerning the ionic homeostasis in erythrocytes, EGCG also mitigated most effectively the changes induced by t-BHP on Na,K-ATPase enzyme in all age groups; however, the effect was again more pronounced in the oldest age group [ 69 ]. A different study of elevated free radical formation induced by an increase in oxygen partial pressure (using in vitro hyperbaric oxygen model for erythrocytes from healthy volunteers) showed that EGCG effectively ameliorated hemorheological abnormality and enhanced erythrocyte deformability [ 98 ].…”

Investigation of oxidative stress parameters in different lifespan erythrocyte fractions in young untrained men after acute exercise

“…The aim of this study was to investigate the effects of acute physical exercise on the oxidative stress process in the erythrocytes of young sedentary healthy male subjects. Taking into account that the redox balance in ageing cells is disturbed in favour of the oxidation processes (Pandey, ), we examined whether the age of the erythrocytes has an effect on the changes resulting from oxidative stress induced by exhaustive exercise. Oxidative stress markers, such as protein thiol groups and lipid peroxidation products, were measured and compared.…”

Modulation Effects of Curcumin on Erythrocyte Ion-Transporter Activity

“…Mutation in the activity of membrane transport systems has been reported in various pathological conditions including diabetes, cancer, neurodisorders, CVD, and aging [ 10 – 13 ]. Impairment in transporters activity and deregulation of ions-homeostasis has been linked with membrane fluidity and susceptibility of membrane toward oxidative damage [ 14 , 15 ].…”