Chronic pain is gender-related, since there is a clear predominance of one sex with respect to the other in most pain syndromes. Gonadal hormones are known to affect the occurrence and incidence of pain. Transsexuals receive cross-sex hormones to develop and maintain somatic characteristics of the opposite sex: male to female transsexuals (MtF) are administered estrogens and anti-androgens, while female to male transsexuals (FtM) are administered androgens. Hence, these subjects represent a model to study the relationship between sex hormones and pain. Questionnaires dealing with sociodemographic data and pain (occurrence, frequency, duration, intensity, location and associated symptoms) were administered to both MtF and FtM transsexuals under hormone treatment for sex reassignment for at least 1 year. Forty-seven MtF and 26 FtM completed the questionnaires. Fourteen of the 47 MtF (29.8%) reported painful conditions, which in 11 subjects were not present before the beginning of hormone treatment. Pain consisted mainly of headaches and breast and musculoskeletal pain. Five subjects suffered from more than one pain condition. Sixteen of the 26 FtM (61.5%) reported pain. In 11 subjects, the pain was present before the beginning of hormone intake, and in 6 of them it improved after testosterone administration. These data suggest that marked changes in sex hormones affect the occurrence of pain in a high percentage of humans but not in all of them. Whether these effects are due to peripheral or central actions of sex steroids is unknown.

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Background: Besides functioning as chemosensors for a broad range of endogenous and synthetic ligands, transient receptor potential vanilloid (TRPV) 1-4 channels have also been related to capsaicin (TRPV1), pain, and thermal stimuli perception, and itching sensation (TRPV1-4). While the expression of the TRPV1-4 genes has been adequately proved in skin, sensory fibres and keratinocytes, less is known about TRPV3 and TRPV4 expression in human blood cells.

BackgroundIn male patients suffering from chronic pain, opioid administration induces severe hypogonadism, leading to impaired physical and psychological conditions such as fatigue, anaemia and depression. Hormone replacement therapy is rarely considered for these hypogonadic patients, notwithstanding the various pharmacological solutions available.MethodsTo treat hypogonadism and to evaluate the consequent endocrine, physical and psychological changes in male chronic pain patients treated with morphine (epidural route), we tested the administration of testosterone via a gel formulation for one year. Hormonal (total testosterone, estradiol, free testosterone, DHT, cortisol), pain (VAS and other pain questionnaires), andrological (Ageing Males' Symptoms Scale - AMS) and psychological (POMS, CES-D and SF-36) parameters were evaluated at baseline (T0) and after 3, 6 and 12 months (T3, T6, T12 respectively).ResultsThe daily administration of testosterone increased total and free testosterone and DHT at T3, and the levels remained high until T12. Pain rating indexes (QUID) progressively improved from T3 to T12 while the other pain parameters (VAS, Area%) remained unchanged. The AMS sexual dimension and SF-36 Mental Index displayed a significant improvement over time.ConclusionsIn conclusion, our results suggest that a constant, long-term supply of testosterone can induce a general improvement of the male chronic pain patient's quality of life, an important clinical aspect of pain management.