A mid‑pandemic night’s dream: Melatonin, from harbinger of anti‑inflammation to mitochondrial savior in acute and long COVID‑19 (Review)

Abstract:

Coronavirus disease 2019 (COVID‑19), a systemic illness caused by severe acute respiratory distress syndrome 2 (SARS‑CoV‑2), has triggered a worldwide pandemic with symptoms ranging from asymptomatic to chronic, affecting practically every organ. Melatonin, an ancient antioxidant found in all living organisms, has been suggested as a safe and effective therapeutic option for the treatment of SARS‑CoV‑2 infection due to its good safety characteristics and broad‑spectrum antiviral medication properties.

Melatonin is essential in various metabolic pathways and governs physiological processes, such as the sleep‑wake cycle and circadian rhythms. It exhibits oncostatic, anti‑inflammatory, antioxidant and anti‑aging properties, exhibiting promise for use in the treatment of numerous disorders, including COVID‑19. The preventive and therapeutic effects of melatonin have been widely explored in a number of conditions and have been well‑established in experimental ischemia/reperfusion investigations, particularly in coronary heart disease and stroke.

Clinical research evaluating the use of melatonin in COVID‑19 has shown various improved outcomes, including reduced hospitalization durations; however, the trials are small. Melatonin can alleviate mitochondrial dysfunction in COVID‑19, improve immune cell function and provide antioxidant properties. However, its therapeutic potential remains underexplored due to funding limitations and thus further investigations are required.

Source: Lempesis IG, Georgakopoulou VE, Reiter RJ, Spandidos DA. A mid‑pandemic night’s dream: Melatonin, from harbinger of anti‑inflammation to mitochondrial savior in acute and long COVID‑19 (Review). Int J Mol Med. 2024 Mar;53(3):28. doi: 10.3892/ijmm.2024.5352. Epub 2024 Feb 1. PMID: 38299237. https://www.spandidos-publications.com/10.3892/ijmm.2024.5352

The global challenges of the long COVID-19

Abstract:

COVID-19 may lead to a perseverance of symptoms after recovery from the disease, a condition known as long COVID, characterized by continual cognitive, somatic and behavioral symptoms. SARS-CoV-2 infection triggers different molecular to tissue level events, given by the inherent features of each patient. The potential pathological changes which determine the array of symptoms are arduous to anticipate.

There is an increasing interest to develop treatment strategies for survivors who experience a long COVID. In this respect, considering the anti-inflammatory, anti-oxidative and cytoprotective effects of melatonin (MEL) on viral infections, its potential links with COVID-19 should be researched. Several studies suggest that administration of MEL may prevent clinical deterioration and even death in patients with acute and long COVID-19.

This paper briefly reviews the current status of knowledge of the pathogenic, clinical, and therapeutic features of Long COVID-19 and forthcoming directions for research and implications for the management and therapy of the disease are analyzed.

Source: Leonor Chacin-Bonilla. The global challenges of the long COVID-19. Journal of Clinical Images and Medical Case Reports. ISSN 2766-7820 https://jcimcr.org/pdfs/JCIMCR-v4-2512.pdf (Full text)

“LONG COVID”-A hypothesis for understanding the biological basis and pharmacological treatment strategy

Abstract:

Infection of humans with SARS-CoV-2 virus causes a disease known colloquially as “COVID-19” with symptoms ranging from asymptomatic to severe pneumonia. Initial pathology is due to the virus binding to the ACE-2 protein on endothelial cells lining blood vessels and entering these cells in order to replicate. Viral replication causes oxidative stress due to elevated levels of reactive oxygen species. Many (~60%) of the infected people appear to have eliminated the virus from their body after 28 days and resume normal activity. However, a significant proportion (~40%) experience a variety of symptoms (loss of smell and/or taste, fatigue, cough, aching pain, “brain fog,” insomnia, shortness of breath, and tachycardia) after 12 weeks and are diagnosed with a syndrome named “LONG COVID.”

Longitudinal clinical studies in a group of subjects who were infected with SARS-CoV-2 have been compared to a non-infected matched group of subjects. A cohort of infected subjects can be identified by a battery of cytokine markers to have persistent, low level grade of inflammation and often self-report two or more troubling symptoms. There is no drug that will relieve their symptoms effectively.

It is hypothesized that drugs that activate the intracellular transcription factor, nuclear factor erythroid-derived 2-like 2 (NRF2) may increase the expression of enzymes to synthesize the intracellular antioxidant, glutathione that will quench free radicals causing oxidative stress. The hormone melatonin has been identified as an activator of NRF2 and a relatively safe chemical for most people to ingest chronically. Thus, it is an option for consideration of re-purposing studies in “LONG COVID” subjects experiencing insomnia, depression, fatigue, and “brain fog” but not tachycardia. Appropriately designed clinical trials are required to evaluate melatonin.

Source: Jarrott B, Head R, Pringle KG, Lumbers ER, Martin JH. “LONG COVID”-A hypothesis for understanding the biological basis and pharmacological treatment strategy. Pharmacol Res Perspect. 2022 Feb;10(1):e00911. doi: 10.1002/prp2.911. PMID: 35029046. https://bpspubs.onlinelibrary.wiley.com/doi/10.1002/prp2.911 (Full text)

Effect of Melatonin Plus Zinc Supplementation on Fatigue Perception in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, multisystem, and profoundly debilitating condition, probably of multifactorial etiology. No effective approved drugs are currently available for its treatment. Several studies have proposed symptomatic treatment with melatonin and zinc supplementation in chronic illnesses; however, little is known about the synergistic effect of this treatment on fatigue-related symptoms in ME/CFS. The primary endpoint of the study was to assess the effect of oral melatonin plus zinc supplementation on fatigue in ME/CFS. Secondary measures included participants’ sleep disturbances, anxiety/depression and health-related quality of life.

A proof-of-concept, 16-week, randomized, placebo-controlled, double-blind trial was conducted in 50 ME/CFS patients assigned to receive either oral melatonin (1 mg) plus zinc (10 mg) supplementation (n = 24) or matching placebo (n = 26) once daily. Endpoint outcomes were evaluated at baseline, and then reassessed at 8 and 16 weeks of treatment and 4 weeks after treatment cessation, using self-reported outcome measures. The most relevant results were the significant reduction in the perception of physical fatigue in the Mel-Zinc group at the final treatment follow-up versus placebo (p < 0.05), and the significant improvement in the physical component summary at all follow-up visits in the experimental group. Urinary 6-sulfatoxymelatonin levels were significantly elevated though the treatment in experimental group vs. placebo (p < 0.0001); however, no significantly differences were observed for zinc concentration among participants. Our findings suggest that oral melatonin plus zinc supplementation for 16 weeks is safe and potentially effective in reducing fatigue and improving the quality of life in ME/CFS.

This clinical study was registered on ClinicalTrials.gov (NCT03000777).

Source: Castro-Marrero J, Zaragozá MC, López-Vílchez I, Galmés JL, Cordobilla B, Maurel S, Domingo JC, Alegre-Martín J. Effect of Melatonin Plus Zinc Supplementation on Fatigue Perception in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial. Antioxidants (Basel). 2021 Jun 23;10(7):1010. doi: 10.3390/antiox10071010. PMID: 34201806. https://pubmed.ncbi.nlm.nih.gov/34201806/

Clinical efficacy of neurometabolic therapy of dissomical disorders in asthenic syndrome

Abstract:

AIM: To analyze the efficacy of cytoflavin in the complex treatment of sleep disorders in asthenic syndrome.

MATERIAL AND METHODS: One hundred patients with sleep disorders and asthenic syndrome of various etiology and severity were studied. The patients were divided into three groups depending on the type of therapy: the first group received intravenous infusions of cytoflavin for 10 days; the second group, in addition to cytoflavin, received per os melatonin (3 mg or 5 mg) at bedtime; the third group in addition to cytoflavin received per os zopiclone (7.5 mg) at bedtime.

RESULTS: On the 14th day of the study, a decrease in severity or complete relief of asthenia manifestations (according to the SHAS scale) and, accordingly, improvement or normalization of sleep in 97% of patients was found. At the same time, during polysomnographic study, the data obtained are characteristic for improving the quality of sleep phases mainly in the first and second groups of patients and, to a lesser extent, in the third group.

CONCLUSION: Cytoflavin effectively suppresses the main manifestations of asthenic syndrome, including sleep disorders.

Source: Esipov AV, Ivolgin AF, Khritinin DF, Katenko SV, Kazakov SP, Karakozov AG, Kalyagin IE, Levchenko OB, Molodova AI. Clinical efficacy of neurometabolic therapy of dissomical disorders in asthenic syndrome. Zh Nevrol Psikhiatr Im S S Korsakova. 2019;119(9):46-51. doi: 10.17116/jnevro201911909146. [Article in Russian; Abstract available in Russian from the publisher] https://www.ncbi.nlm.nih.gov/pubmed/31626218

Agomelatine but not melatonin improves fatigue perception: a longitudinal proof-of-concept study

Abstract:

Chronic Fatigue Syndrome (CFS) represents a disabling condition characterized by persistent mental and physical fatigue, bodily discomfort and cognitive difficulties. To date the neural bases of CFS are poorly understood; however, mono-aminergic abnormalities, sleep-wake cycle changes and prefrontal dysfunctions are all thought to play a role in the development and maintenance of this condition.

Here we explored in a group of 62 CFS subjects the impact on fatigue levels of agomelatine, an antidepressant with agonist activity at melatonin receptors (MT1 and MT2) and antagonist activity at serotoninergic 2C receptors (5HT2C). To tease out the relative effects of MT-agonism and 5HT2C antagonism on fatigue, we compared agomelatine 50mg u.i.d. with sustained release melatonin 10mg u.i.d. in the first 12-week-long phase of the study, and then switched all melatonin-treated subjects to agomelatine in the second 12-week-long phase of the study.

Agomelatine treatment, but not melatonin, was associated with a significant reduction of perceived fatigue and an increase in perceived quality of life. Moreover the switch from melatonin to agomelatine was associated with a reduction of fatigue levels. Agomelatine was well tolerated by all enrolled subjects. Our data, albeit preliminary, suggest that agomelatine treatment could represent a novel useful approach to the clinical care of subjects with CFS.

Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

 

Source: Pardini M, Cordano C, Benassi F, Mattei C, Sassos D, Guida S, Serrati C, Primavera A, Amore M, Cocito L, Emberti Gialloreti L. Agomelatine but not melatonin improves fatigue perception: a longitudinal proof-of-concept study. Eur Neuropsychopharmacol. 2014 Jun;24(6):939-44. doi: 10.1016/j.euroneuro.2014.02.010. Epub 2014 Feb 25. https://www.ncbi.nlm.nih.gov/pubmed/24636462

 

Influence of melatonin on fatigue severity in patients with chronic fatigue syndrome and late melatonin secretion

Abstract:

The effect of melatonin, a chronobiotic drug, was explored in 29 patients with chronic fatigue syndrome (CFS) and Dim Light Melatonin onset (DLMO) later than 21.30 hours, reflective of delayed circadian rhythmicity. The patients took 5 mg of melatonin orally, 5 h before DLMO during 3 months.

Their responses to the checklist individual strength (CIS), a reliable questionnaire measuring the severity of personally experienced fatigue, were assessed twice with a 6-week interval immediately before the treatment and once after 3 months treatment.

In the pre-treatment period the fatigue sub-score improved significantly. After treatment, the total CIS score and the sub-scores for fatigue, concentration, motivation and activity improved significantly. The sub-score fatigue normalized in two of the 29 patients in the pre-treatment period and in eight of 27 patients during treatment. This change was significant.

In the patients with DLMO later than 22.00 hours (n=21) the total CIS score and the sub-scores for fatigue, concentration and activity improved significantly more than in the patients (n=8) with DLMO earlier than 22.00 hours. Melatonin may be an effective treatment for patients with CFS and late DLMO, especially in those with DLMO later than 22.00 hours.

 

Source: van Heukelom RO, Prins JB, Smits MG, Bleijenberg G. Influence of melatonin on fatigue severity in patients with chronic fatigue syndrome and late melatonin secretion. Eur J Neurol. 2006 Jan;13(1):55-60. https://www.ncbi.nlm.nih.gov/pubmed/16420393

 

Therapy of circadian rhythm disorders in chronic fatigue syndrome: no symptomatic improvement with melatonin or phototherapy

Abstract:

BACKGROUND: Patients with chronic fatigue syndrome (CFS) show evidence of circadian rhythm disturbances. We aimed to determine whether CFS symptoms were alleviated by melatonin and bright-light phototherapy, which have been shown to improve circadian rhythm disorders and fatigue in jet-lag and shift workers.

DESIGN: Thirty patients with unexplained fatigue for > 6 months were initially assessed using placebo and then received melatonin (5 mg in the evening) and phototherapy (2500 Lux for 1 h in the morning), each for 12 weeks in random order separated by a washout period. Principal symptoms of CFS were measured by visual analogue scales, the Shortform (SF-36) Health Survey, Mental Fatigue Inventory and Hospital Anxiety and Depression Scale. We also determined the circadian rhythm of body temperature, timing of the onset of melatonin secretion, and the relationship between these.

RESULTS: Neither intervention showed any significant effect on any of the principal symptoms or on general measures of physical or mental health. Compared with placebo, neither body temperature rhythm nor onset of melatonin secretion was significantly altered by either treatment, except for a slight advance of temperature phase (0.8 h; P = 0.04) with phototherapy.

CONCLUSION: Melatonin and bright-light phototherapy appear ineffective in CFS. Both treatments are being prescribed for CFS sufferers by medical and alternative practitioners. Their unregulated use should be prohibited unless, or until, clear benefits are convincingly demonstrated.

 

Source: Williams G, Waterhouse J, Mugarza J, Minors D, Hayden K. Therapy of circadian rhythm disorders in chronic fatigue syndrome: no symptomatic improvement with melatonin or phototherapy. Eur J Clin Invest. 2002 Nov;32(11):831-7. http://www.ncbi.nlm.nih.gov/pubmed/12423324

 

Melatonin levels in women with fibromyalgia and chronic fatigue syndrome

Abstract:

OBJECTIVE: Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are stress associated disorders mainly affecting women. FM is characterized primarily by widespread musculoskeletal pain, and CFS by profound debilitating fatigue, but there is considerable overlap of clinical symptoms between these 2 syndromes. Neuroendocrine abnormalities have been noted in both FM and CFS and desynchronization of circadian systems has been postulated in their etiology. The pineal hormone melatonin is involved in synchronizing circadian systems and the use of exogenous melatonin has become widespread in patients with FM and CFS.

METHODS: We examined the characteristics and relationship of melatonin and cortisol levels in premenopausal women with FM (n = 9) or CFS (n = 8), compared to age and menstrual cycle phase matched controls. Blood was collected from an indwelling intravenous catheter every 10 min over 24 h, and plasma melatonin and cortisol were determined by radioimmunoassay at 60 and 10 min intervals, respectively.

RESULTS: Night time (23:00-06:50) plasma melatonin levels were significantly higher in FM patients compared to controls (p<0.05), but there was no significant difference in melatonin levels between CFS patients and controls. No differences in the timing of cortisol and melatonin secretory patterns and no internal desynchronization of the 2 rhythms were found in either patient group, compared to controls.

CONCLUSION: Raised plasma melatonin concentrations have been documented in several other conditions that are associated with dysregulation of neuroendocrine axes. Increased melatonin levels may represent a marker of increased susceptibility to stress induced hypothalamic disruptions. These data indicate that there is no rationale for melatonin replacement therapy in patients with FM and CFS.

 

Source: Korszun A, Sackett-Lundeen L, Papadopoulos E, Brucksch C, Masterson L, Engelberg NC, Haus E, Demitrack MA, Crofford L. Melatonin levels in women with fibromyalgia and chronic fatigue syndrome. J Rheumatol. 1999 Dec;26(12):2675-80. http://www.ncbi.nlm.nih.gov/pubmed/10606381

 

The fatigue syndrome in autoimmune thyroiditis with polyglandular activation of autoimmunity

Abstract:

The authors compared in a group of 118 patients with autoimmune thyroiditis and a positive antibody titre against ovaries the grade of fatigue with the presence of organ specific and non-specific autoantibodies in the peripheral blood stream, antibodies against EBV and CMV, immunoglobulin concentrations, biochemical parameters of the lipid metabolism, glucose tolerance, ion balance and melatonin and serotonin levels. Patients with autoimmune thyroiditis were differentiated according to the degree of fatigue into three groups: 38 with fatigue typical for CFS, 30 with occasional fatigue and 50 without the feeling of fatigue.

Fatigue of the CFS type was characterized by a significantly higher incidence of autoantibodies against the adrenals and a higher cholesterol level. Increased fatigue of the patients was associated with a lower melatonin level, a higher serotonin level and a lower M/S ratio as compared with patients without fatigue. In other indicators no differences were found. Fatigue in CFS could be associated, similarly as in autoimmune endocrinopathies, with impaired immunoendocrine regulation. In autoimmune thyroiditis, regardless of the concomitant presence of fatigue, in addition to antibodies against thyroid peroxidase most frequently antibodies against the ovaries were detected.

 

Source: Sterzl I, Fucíková T, Hrdá P, Matucha P, Zamrazil V. The fatigue syndrome in autoimmune thyroiditis with polyglandular activation of autoimmunity. Vnitr Lek. 1998 Aug;44(8):456-60. [Article in Czech] http://www.ncbi.nlm.nih.gov/pubmed/10358448