The clinical efficacy of melatonin in the treatment of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials

Ramelteon exposure and survival of critically Ill sepsis patients: a retrospective study from MIMIC-IV

BACKGROUND

The effect of ramelteon, a melatonin receptor agonist, on survival in septic patients remains unknown. The purpose of this retrospective cohort study was to explore the relationship between ramelteon exposure and survival outcomes in septic patients.

METHODS

Data from septic patients admitted to the intensive care unit (ICU) were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, with patients categorized into ramelteon exposure and non-exposure groups based on the use of ramelteon. The primary outcome was 30-day mortality, and secondary outcomes included 90-day mortality, in-hospital mortality, length of ICU stay, and hospital stay. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were employed to address confounding variables. Kaplan-Meier (K-M) analysis and Cox proportional hazards regression models for stepwise regression were utilized to assess the impact of ramelteon exposure on survival.

RESULTS

This study included 22,152 unexposed patients and 2,708 exposed patients, resulting in 2,607 matched pairs after PSM. Following PSM, ramelteon exposure was associated with significantly lower in-hospital mortality (11.6% vs.19.7%, p < 0.001), 30-day mortality (13.4% vs. 23.2%, p < 0.001), and 90-day mortality (22.1% vs. 30%, p < 0.001).K-M curves demonstrated a significant difference in 30-day and 90-day mortality between the two groups (P < 0.001), irrespective of PSM application. Both PSM (hazard ratio [HR] = 0.53, 95% confidence intervals [CIs] 0.47-0.61, p < 0.001) and IPTW models (HR = 0.59, 95% CI 0.50-0.70, p < 0.001) indicated a significant positive effect of ramelteon usage on 30-day mortality among septic patients compared to the non-exposure group.

CONCLUSIONS

This exploratory, retrospective study suggests an association between ramelteon exposure and reduced 30-day and 90-day mortality in septic patients compared with the non-exposure group. Considering the limitations of the retrospective design and the potential for unmeasured confounding, well-designed prospective studies and randomized controlled trials will be needed to confirm these findings.

Melatonin's Impact on Cytokine Storm and Modulation of Purinergic Receptors for COVID-19 Prognosis: A Mental Health Perspective

In 2019, coronavirus disease 2019 (COVID-19) started a global health crisis and was associated with high rates of depression and anxiety. Both mental disorders and COVID-19 exhibit similarities in pathophysiology, characterized by immune system overactivation, involvement of the purinergic system, and oxidative stress, besides additional factors and systems likely contributing to the complexities of these conditions. The purinergic system contributes to the disease-influenced immune response, an essential strategy for controlling pathophysiological effects. In this context, the hormone melatonin emerges as a substance that can modulate the purinergic system and contribute positively to the pathophysiology of SARS-CoV-2 infection and associated mental disorders. Melatonin is a hormone that regulates the body's circadian rhythms, plays an essential role in regulating sleep and mood, and modulates the purinergic system. Recent studies suggest melatonin's anti-inflammatory and antioxidant properties may benefit COVID-19. This review explores melatonin's impact on inflammatory cytokine storm in COVID-19 through purinergic system modulation.

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

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.

Assessing the antiviral potential of melatonin: A comprehensive systematic review

This review assesses the antiviral potential of melatonin through comprehensive analysis of studies across human subjects, animal models, cell cultures, and in-silico simulations. The search strategy targeted relevant research until 22 June 2023, resulting in 20 primary studies after screening and deduplication. The findings highlight strong evidence supporting antiviral properties of melatonin. In silico studies identify melatonin as a candidate against SARS-CoV-2, reducing cytokine storm-related respiratory responses. Cell culture experiments reveal its multifaceted effects on different viruses including respiratory syncytial virus, anti-dengue virus, transmissible gastroenteritis virus, and encephalomyocarditis virus. Animal studies show melatonin reduces mortality and viral replication in various infections such as Venezuelan equine encephalomyelitis and COVID-19. Clinical trials show how it could be evaluated, but with no conclusive evidence of efficacy and safety so far from large, double-blind placebo-controlled trials. These insights showcase the potential of melatonin as a versatile antiviral agent with immunomodulatory, antioxidant, anti-inflammatory and antiviral properties. In summary, our review highlights melatonin's promising antiviral properties across diverse settings. Melatonin's immunomodulatory and antiviral potential makes it a compelling candidate for further investigation, emphasising the need for rigorous clinical trials to establish its safety and efficacy against viral infections.