Thymulin: An Emerging Anti-Inflammatory Molecule

Thymulin is a neuroendocrine hormone with immunoregulatory actions. Originally known as 'serum thymic factor' (FTS), thymulin binds to a carrier protein and zinc (Zn2+) to exert its biologic properties. Thymulin, albeit an es- sential hormone for the T lymphocyte differentiation and the normalization of the ratio of T-helper cells to suppressor cells, accumulating evidence suggests its involvement in inflammations of various etiologies. Recently, thymulin has been shown to have anti-nociceptive effects in hyperalgesia and in pain of neurogenic origin, ostensibly through action on sen- sory afferents and the release of anti-inflammatory mediators. Given its anti-inflammatory potential, thymulin downregu- lates the release of inflammatory mediators, such as cytokines and chemokines, upregulates anti-inflammatory factors, such as interleukin (IL)-10, and exerts molecular control via the regulation of transcription factors and mediators. Recent evidence tends to indicate that thymulin can be a therapeutic agent in many inflammatory diseases and in pathological conditions affecting the peripheral and/or the central nervous system. This review discusses current concepts in the anti- inflammatory actions of thymulin and correlates this activity with an emerging theme for therapeutic treatment.