Decreased number of oxytocin neurons in the paraventricular nucleus of the human hypothalamus in AIDS.

The number of immunocytochemically identified vasopressin (AVP) and oxytocin (OXT) neurons was determined morphometrically in the paraventricular nucleus of the hypothalamus of 20 acquired immunodeficiency syndrome (AIDS) patients and 10 controls. The AIDS group consisted of 14 homosexual males (age range 25-62 years), four of whom had a probable HIV-1 associated dementia complex, and six non-demented heterosexuals (four males and two females, age range 21-73 years). Ten males without a primary neurological or psychiatric disease served as a control group. The number of OXT-expressing neurons in the paraventricular nucleus of both groups of AIDS patients was approximately 40% lower than that of the controls. In contrast, the three groups showed no significant differences in the number of AVP-expressing neurons in the paraventricular nucleus. Since there were no significant differences in the number of AVP and OXT cells between the homosexual and heterosexual subjects with AIDS, the morphological difference in the paraventricular nucleus seems to be related to AIDS and not to sexual orientation. No inflammatory changes were found in the paraventricular nucleus area. The selective changes in the OXT neurons of the paraventricular nucleus may be the basis for part of the neuroendocrine, autonomic dysfunction or vegetative symptoms in AIDS.