Plasma esterases and inflammation in ageing and frailty

Esterases are enzymes of drug metabolism known to be reduced in frail older people and during acute illness. The mechanism for this is unknown. The aim of this study was to examine esterase activity and inflammation in ageing and frailty.

Thirty frail patients (mean age 84.9 years) dependent on continuing inpatient care, 40 patients of intermediate frailty attending Day Hospital (84.2 years), 40 fit older controls (82.7 years) and 30 young controls (23.3 years) were studied. Frailty indicators, plasma esterase activities and markers of inflammation were measured.

With increasing patient frailty, C-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) increased significantly and esterase activity, with the exception of aspirin esterase, fell significantly (p < 0.005). There were significant negative correlations between log-transformed IL-6 and acetylcholinesterase (r = -0.354, p < 0.01), butyrylcholinesterase (r = -0.392, p < 0.01) and benzoylcholinesterase activity (r = -0.241, p < 0.05) and significant negative correlations between TNF-alpha and acetylcholinesterase (r = -0.223, p < 0.01), butyrylcholinesterase (r = -0.279, p < 0.01) and benzoylcholinesterase activity (r = -0.253, p < 0.01). Aspirin esterase activity did not correlate with IL-6 or TNF- alpha.

Frailty was associated with higher inflammatory markers and lower esterase activity. There was a weak but significant negative correlation between both IL-6 and TNF-alpha and the activity of three of four esterases. The negative correlation between esterase activity and inflammatory markers may have a causal basis, comparable to the inflammatory suppression of cytochrome P-450 enzymes.