Current Approaches for the Treatment with Thyroid Hormone Analogs

Thyroid hormones affect the function of nearly every organ of the body, including lipid homeostasis, regulation of body weight and cardiovascular effects. Application of thyroid hormones for the treatment of metabolic and cardiovascular disorders is not possible due to their side effects, but the discovery of drugs specifically affecting some of these functions may overcome this limitation. In the current review, we outline the physiology of thyroid receptors and summarize patterns of new drugs that bind to different receptors, thereby providing the base for a treatment of patients with metabolic and cardiovascular disorders. More recently, thyrotropin releasing hormone (TRH) has been shown to improve thyroid function in patients with nonthyroidal illness syndrome (NTIS), and may provide a future therapeutic option for critically ill patients. In addition, there is evidence that TRH is involved in central nervous regulation of blood glucose and repair of brain damage. However, therapeutical application of TRH is hampered by its rapid metabolization. Specific long acting analogues may therefore allow better treatment of these conditions. Recent patents on design and therapeutical use of these drugs are summarized in this manuscript.