Potential benefits of melatonin in organ transplantation: a review

Abstract

Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acidl-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation.

Melatonin therapy adds extra benefit to varicecelectomy in terms of sperm parameters, hormonal profile and total antioxidant capacity: A placebo-controlled, double-blind trial

“…Melatonin is an indoleamine produced mainly by the pineal gland and it has a potent free radical scavenger activity with subsequent antioxidant and antiapoptotic functions (Esteban‐Zubero et al., ). Among the known antioxidants, melatonin has high efficacy.…”

Melatonin: a hepatoprotective agent against radioiodine toxicity in rats

“…Although melatonin was fi rst considered to solely be a circadian cycle regulator, several studies have shown that it is effective as a free radical scavenger and antioxidant agent. In addition to the regulation of circadian biology, melatonin has also been shown to modulate several molecular pathways of infl ammation, oxidative stress, and cellular injury and have vasorelaxant and anti-fi brotic properties (3,4).…”

Melatonin Mitigates Mitochondrial Meltdown: Interactions with SIRT3

“…Some of the allied processes utilized by melatonin to reduce these catastrophic effects, e.g., indiscriminate molecular destruction which ultimately leads to cellular apoptosis, include improving the efficacy of the mitochondria respiratory complexes [129,183,184], enriching ATP production [185,186], reducing free radical generation by limiting electron leakage, commonly referred to as radical avoidance [128], upregulating antioxidative enzymes [187,188], stimulating glutathione synthesis [189,190], direct radical detoxification [103,191] and probably yet to be defined means. The outcome of these combined actions is the preservation of cellular and organ physiology, as well as the prevention of organismal death, by mitigating cellular loss due to apoptosis [167,192,193,194,195].…”