Lipid peroxidation in the lymphocyte membrane and protein oxidation in the serum of elderly people. Are they potential markers of frailty and dependence? Preliminary results

© 2015 SEGG. Objective: To study the relationships between lipid peroxidation of the lymphocyte membrane, protein oxidation and different markers of frailty and dependence. Methods: The sample consisted of 15 elderly patients in an intermediate and long-term care center, who had not suffered any acute process recently. The geriatric assessment included, functional capacity (Barthel and Lawton indexes), comorbidity (Charlson index), and cognitive function (Mini Mental State Examination of Folstein). The frailty was estimated by the Hospital Admission Risk Profile (high risk of frailty 4-5 points, intermediate/low 0-3 points) and Frailty Scale of Rockwood (mild frailty < 6, intermediate frailty/severe ≥ 6). Lipid peroxidation was studied by determination of conjugated dienes and trienes. Analysis of protein oxidation was performed by determining malondialdehyde bound to plasma proteins, corrected by total protein quantification. Results: Elderly patients at high risk of frailty according to Hospital Admission Risk Profile presented mean values of conjugated dienes of 7.94 ± 1.32%, trienes of 1.75 ± 0.51%, and malondialdehyde bound to plasma proteins of 141.9 ± 27.3 nmol/g. In the group of intermediate/low risk, these values were 4.96 ± 2.77% ( P= .035), 1.37 ± 0.78% ( P= .337) and 96.4 ± 31.5 nmol/g ( P= .022), respectively. In those with intermediate/severe frailty according to the Frailty Scale of Rockwood, these values were 7.06 ± 2.18%; 1.73 ± 0.50% and 119.6 ± 37.9 nmol/g, respectively, and in those with mild frailty 2.56 ± 1.48% ( P= 014); 0.61 ± 0.58% ( P= 020) and 173.2 ± 51.9 nmol/g ( P= .144), respectively. There was good correlation between the Hospital Admission Risk Profile score and malondialdehyde bound to plasma proteins (r = 0.70; P= 01) and between the Frailty Scale of Rockwood score and conjugated dienes (r = 0.65; P= 01). Conclusions: Elderly patients with a higher degree of frailty appear to have greater levels of lipid peroxidation, which could be considered a marker of frailty.