Cholesterol and cholesterol sulphate concentration in the cell membrane complex of human scalp hair — A biomarker of aging?

Abstract

Cell to cell cohesion in fully keratinized hair is mediated by a cell membrane complex which contains covalently bound (integral) hair lipids. The influence of aging on concentrations of integral cholesterol sulphate (CHSU) and cholesterol (CH) in human scalp hair shafts, and the relationship between hair and plasma lipids were examined in 50 subjects, aged 18 to 87 years, and in one case of Werner's syndrome. Hair CHSU concentrations were distributed normally and were significantly higher in male subjects with elevated plasma CH levels (>5.17 mmol/l) than in those with normal plasma CH levels (806+/-134 versus 624+/-155 nmol/g hair, p<0.001). Female subjects with elevated plasma CH levels had even lower hair CHSU, values (515+/-167 nmol/g hair, p<0.05) than men with normal plasma CH. The almost white hairs of the Werner's syndrome patient displayed low levels of CHSU, possibly indicating a precarious hair stability. A small but statistically significant linear correlation between donor age and integral CH in hair (n=51; y=97.7+0.9x; cc=0.32; p<0.05) was detected. No correlation between hair CHSU and age could be demonstrated. Since internal hair lipid concentrations do not correlate with plasma lipids, the age associated increase of hair CH as well as the observed gender differences in hair CHSU concentration may be related to alterations in the process of keratinization. Hair CH analysis seems to be of little significance in the clinical diagnosis of hypercholesterolemia.