Cancer-related Fatigue, Inflammation and Thyrotropin-releasing Hormone

Aging and aging related illnesses such as cancer have been associated with inflammatory changes. Cancerrelated behavioral comorbidities such as fatigue, sleep disturbances, depression have also been associated with inflammation, hypothalamic-pituitary-adrenal (HPA) axis dysregulation and other neuroendocrine changes. From a clinical perspective, cancer-related fatigue demonstrates striking similarities with the cytokine-induced sickness phenomenon in animal models. Thyrotopin-releasing hormone (TRH) plays a homeostatic role in its interaction with several biological systems, including a critical role in its interactions with the immune system. Considerable evidence supports a pivotal role for TRH in the inflammatory processes with specific relevance to the "cytokine-induced sickness behavior" paradigm. Additionally, TRH exerts arousing and analeptic effects in instances of behavioral depression. In a small proof-of-concept study conducted by our group, we investigated TRH administration as a treatment fatigue in cancer survivors in comparison with saline administration using a double-blind, crossover design. We also evaluated impact of TRH/saline administration on the inflammatory markers in these patients. TRH administration was associated with significant improvement (p < 0.05) in fatigue levels as measured by the Visual Analog Scale-Energy (VAS-E), was associated with significant (p < 0.05) improvement in sleep disturbances and improved quality of life. Notably, TRH administration was associated with decrease in C-reactive protein (CRP) levels, a marker of inflammation. This decrease in CRP level with TRH administration was associated with improvement in energy levels as measured by the VAS-E. The present review supports potential utility of TRH-based therapeutics in medical and psychiatric disorders with underlying inflammatory processes.