Investigation of Serum Claudin-5 Levels in Patients with Heroin Addiction

In this study, we investigated the potential effects of heroin on the blood-brain barrier (BBB) through the claudin-5 protein.

A total of 108 subjects participated in this study, of whom 53 were individuals with heroin addiction (HA) and 55 were healthy controls (C). 26 patients were active heroin users (AHU), and 27 were in remission (R).

Our results show that claudin-5 levels were significantly elevated in the HA group compared with healthy individuals. This elevation was present in both HA subgroups (AHU and R). In our receiver operating characteristic analysis to determine the discriminatory power of claudin-5 values, we obtained the highest area under the curve (AUC) values for the comparison of the R-C group, the HA-C group, and the AHU-C group (AUC: 0.824, 0.813, 0.803, respectively).

Our results suggest that serum claudin-5 concentrations are significantly elevated in individuals with HA, regardless of the current phase of drug use, indicating persistent changes in the BBB. Claudin-5 may be a promising peripheral biomarker for heroin-related neurovascular disorder. However, further longitudinal and mechanistic studies are needed to elucidate the temporal dynamics of claudin-5 expression and its relationship to neurobiological recovery during R.