Circulating levels of soluble receptor for advanced glycation end products in neurodegenerative and vascular dementia

Dipeptidyl peptidase IV (DPPIV or CD26) is an ubiquitously expressed protease that could play a role in the pathogenesis of anxiety in view of its capacity to cleave several behaviourally active neuropeptides. Hereto we sought to determine the relationship between phobic anxiety, as measured by the Crown-Crisp index, and circulating levels of soluble CD26 (sCD26) in a large cohort of 1017 Italian women participating in a general health survey. The association between sCD26 levels and phobic anxiety was tested using simple correlation analysis, linear regression and multivariate logistic regression analysis. A highly significant inverse association was found between sCD26 concentrations and anxiety scores both in simple correlation and linear regression analysis. Compared with subjects in the first tertile of sCD26 levels, the age-adjusted odds ratio for scoring >/=6 compared to scoring 0 or 1 was 0.31 (95% CI: 0.18-0.74) for the second and 0.47 (95% CI: 0.34-0.63) for the third tertile. Altogether, our data suggest that reduced plasma sCD26 concentrations could be a marker of high levels of phobic anxiety in women.