Salivary proteome analysis of crack cocaine dependents

Salivary proteomic analysis may help to understand physiopathological changes in crack cocaine dependents. This study aimed to compare the salivary protein profile between crack cocaine dependents and non-drug users.

Nine heavy smokers and alcohol consumers men admitted to rehab due to crack cocaine abuse and nine non-drug users age-matched men were evaluated. Unstimulated whole saliva was collected. Proteomic analysis was performed by mass spectrometer. Data were processed using ProteinLynx GlobalServer software. Results were obtained by searching the Homo sapiens database from the UniProt catalog. The search tool IBI-IMIM was used to identify proteins candidates for biomarkers.

The mean age of crack cocaine and control groups was 36.89 ± 7.78 and 35.78 ± 6.68 years, respectively. 458 salivary proteins were identified in both groups; 305 proteins in the crack cocaine group. Among the 68 proteins presented in both groups, 29 were down-regulated (i.e. "Statherin" and "Transforming growth factor-beta-induced protein ig-h3" were down-regulated at least 10-fold) and 27 up-regulated (i.e. "Negative elongation factor" was up-regulated 19-fold) in the crack cocaine group compared to controls. 90 out of the 458 proteins found in the proteomic analysis were identified as candidates for biomarkers of diseases. Among these, 65 (72.22 %) were detected in the crack cocaine group.

Crack cocaine dependents with chronic alcohol and tobacco use have a higher number of proteins in saliva compared to non-drug users. 22.3 % of salivary proteins present in crack cocaine dependents were present in controls; 3.9 % of them were expressed in similar quantity.