Human carotid body neuroglobin, vascular endothelial growth factor and inducible nitric oxide synthase expression in heroin addiction.

The carotid body (CB) represents the prime site for detecting and responding to hypoxia. Since the role of heroin in respiratory depression with consequent hypoxia is known, the authors were able to investigate morphological and molecular modifications occurring in the CB of heroin addicted subjects compared to subjects who died because of trauma. CB sampled from six 27 year old subjects, slides were treated with Mallory Trichrome staining or used for immunohistochemical analysis to detect Neuroglobin (NGB), Hypoxia Inducible Factor-1 (HIF-1α), Vascular Endothelial Growth Factor (VEGF), Inducible Nitric Oxide Synthase (i-NOS), Bax and cleaved Caspase-3 proteins. Mallory Trichrome staining shows an increase in the connective tissue in heroin subjects compared to controls and a parallel reduction in parenchymal area. Immunohistochemical analyses in heroin subjects found a decrease in NGB and an increase in HIF-1α and VEGF compared to controls; i-NOS expression was not statistically significant. Bax and cleaved caspase-3 were positive only in the heroin subjects. These results could confirm the typical hypoxic condition occurring in heroin addicts. Since NGB may function as a reactive oxygen or nitrogen species scavenger and as apoptotic cell death protector, the decrease in its expression may suggest a key role of this globin in human CB impairment due to heroin addiction.