Melatonin: A pleiotropic molecule regulating inflammation

Abstract

Melatonin is a neurohormone produced by the pineal gland that regulates sleep and circadian functions. Melatonin also regulates inflammatory and immune processes acting as both an activator and inhibitor of these responses. Melatonin demonstrates endocrine, but also paracrine and autocrine effects in the leukocyte compartment: on one side, leukocytes respond to melatonin in a circadian fashion; on the other side, leukocytes are able to synthesize melatonin by themselves.With its endocrine and paracrine effects, melatonin differentially modulates pro-inflammatory enzymes, controls production of inflammatory mediators such as cytokines and leukotrienes and regulates the lifespan of leukocytes by interfering with apoptotic processes. Moreover, its potent anti-oxidant ability allows scavenging of oxidative stress in the inflamed tissues. The interesting timing of pro-and anti-inflammatory effects, such as those affecting lipoxygenase activity, suggests that melatonin might promote early phases of inflammation on one hand and contribute to its attenuation on the other hand, in order to avoid complications of chronic inflammation. This review aims at giving a comprehensive overview of the various inflammatory pathways regulated by this pleiotropic hormone.

Atopic Dermatitis, Melatonin, and Sleep Disturbance

“…33 Melatonin also has immunomodulatory and antiinflammatory effects. 34,35 We found that nocturnal melatonin levels were significantly higher in the patients with AD compared with the controls. It is also our novel finding that in patients with AD, a higher nocturnal melatonin level was associated with better sleep efficiency, less sleep fragmentation, and milder disease severity.…”

A Double-Blind, Placebo-Controlled Trial Related to the Effects of Melatonin on Oxidative Stress and Inflammatory Parameters of Obese Women

“…Melatonin and its metabolites directly scavenge free radicals [15] and stimulate the activity and expression of antioxidant enzymes [23][24][25]. It also decreases production of proinflammatory cytokines by suppressing the mRNA expression of TNF-α, IL-1β, IL-6, and iNOS [17,26,27]. The overall findings indicate the efficacy of using melatonin as a therapeutic tool to prevent obesity-related disorders.…”

“…During the past decade, several studies have supported the potential health benefits of melatonin including antioxidation, anti-inflammatory, immunomodulatory, body fat mass, and weight regulatory effects [10][11][12][13][24][25][26][27][28].…”

Inflammation and the Silent Sequelae of Stroke

“…Agomelatine is a a b c d member of a novel class of new antidepressants which are melatonin agonists; it has been approved by the European Union, after being shown to have similar efficacy to SSRIs for the treatment of depression [96,97]. Melatonin agonists have numerous effects on the immune system, most of which serve to limit inflammation [98]. Finally, nonpharmacologic approaches are also used to treat depression; these approaches include vagal nerve stimulation and exercise.…”