Melatonin corrects reticuloendothelial blockade and iron status in haemodialysed patients

Deficient synthesis of melatonin in COVID-19 can impair the resistance of coronavirus patients to mucormycosis

In addition to uncontrolled diabetes and the excess use of corticosteroids, it is believed that other factors may be responsible for the recent spurt of COVID-19 associated mucormycosis (CAM). In the present paper it is argued that COVID-19 increases the susceptibility of the patients to mucormycosis by augmenting the virulence factors of the mucor species, where deficient synthesis of melatonin plays a key role. Melatonin is synthesized from tryptophan via the serotonin pathway and melatonin deficiency in COVID-19 arises from the faulty absorption of tryptophan from the food because SARS-CoV-2 downregulates angiotensin-converting enzyme-2, the chaperone of the transporter of tryptophan. The enhanced fungal virulence in COVID-19 can be mitigated by correcting the melatonin deficiency as melatonin can prevent iron acquisition of the mucor species and inhibit their morphological transition from the yeast to the virulent hyphal form, given the fact that melatonin is an iron chelator, calmodulin blocker and inhibitor of myeloperoxidase as well as inhibitor of ferroptosis and pyroptosis. Also, by lowering the expression of glucose-regulated protein 78 and by inhibiting the suppression of T-cell immunity, melatonin can further increase the resistance of the patients to mucormycosis. Accordingly, clinical trials should be carried out on tryptophan supplementation, administration of selective serotonin reuptake inhibitors (to increase serotonin, the precursor of melatonin), and exogenous melatonin to find out how they perform in eliminating or reducing the propensity of the coronavirus patients to CAM.

The Coronavirus Disease 2019 (COVID-19): Key Emphasis on Melatonin Safety and Therapeutic Efficacy

Viral infections constitute a tectonic convulsion in the normophysiology of the hosts. The current coronavirus disease 2019 (COVID-19) pandemic is not an exception, and therefore the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, like any other invading microbe, enacts a generalized immune response once the virus contacts the body. Melatonin is a systemic dealer that does not overlook any homeostasis disturbance, which consequently brings into play its cooperative triad, antioxidant, anti-inflammatory, and immune-stimulant backbone, to stop the infective cycle of SARS-CoV-2 or any other endogenous or exogenous threat. In COVID-19, the corporal propagation of SARS-CoV-2 involves an exacerbated oxidative activity and therefore the overproduction of great amounts of reactive oxygen and nitrogen species (RONS). The endorsement of melatonin as a possible protective agent against the current pandemic is indirectly supported by its widely demonstrated beneficial role in preclinical and clinical studies of other respiratory diseases. In addition, focusing the therapeutic action on strengthening the host protection responses in critical phases of the infective cycle makes it likely that multi-tasking melatonin will provide multi-protection, maintaining its efficacy against the virus variants that are already emerging and will emerge as long as SARS-CoV-2 continues to circulate among us.

Melatonin Improves Erythropoietin Hyporesponsiveness via Suppression of Inflammation

BACKGROUND

Inadequate response to Erythropoietin Stimulating Agents (ESA) despite using relatively larger doses regimen represents a potential risk factor of Cardiovascular (CV) related mortality in addition to health-care economic problems in anemic patients with Chronic Kidney Disease (CKD). Erythropoietin (EPO) hyporesponsiveness related to inflammation has been increased progressively. Melatonin is well known as a potent anti-inflammatory agent. Therefore, the current study was designed to evaluate whether melatonin could improve anemic patients response to EPO.

METHODS

This single controlled clinical study was carried out in 41 CKD patients with hemoglobin (Hb) levels less than 11g/dl divided randomly in a 1:1 ratio into 2 groups; treatment group who received 5mg melatonin plus their regular treatments and control group who received their regular treatments only. Hematological and iron status parameters include Hb level, serum iron (S. iron), Transferrin Saturation Ratio (TSAT) and serum ferritin (S. ferritin) in addition to inflammatory parameters that include tissue necrotic factor alfa (TNF-α), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) determined before and after 12 weeks of treatment.

RESULTS

Melatonin remarkably increases the Hb level with a significant increase in S. iron and TSAT compared to baseline. The elevation of S. iron and TSAT was significantly higher in the melatonin group. Additionally, all inflammatory markers estimated were reduced significantly by melatonin compared to base line and control group.

CONCLUSION

The results of the current study showed that melatonin has an advantageous effect on improving EPO response in anemic patients with CKD.

Comparison of the Protective Effects of Erythropoietin and Melatonin on Renal Ischemia-Reperfusion Injury

Background

Renal ischemia-reperfusion (IR) contributes to the development of acute renal failure (ARF). Oxygen free radicals are considered to be the principal components involved in the pathophysiological tissue alterations observed during renal IR.

Objectives

In this study, we compared the effects of melatonin (MEL) and erythropoietin (EPO), both known antioxidant and anti-inflammatory agents, on IR-induced renal injury in rats.

Materials and Methods

Wistar albino rats were unilaterally nephrectomized and then subjected to 45 minutes of renal pedicle occlusion followed by 24 hours of reperfusion. MEL (10 mg/kg, i.p) and EPO (5000 U/kg, i.p) were administered prior to the onset of ischemia. After 24 hours of reperfusion and following decapitation, blood samples were collected for the determination of the hemoglobin (Hb) and hematocrit (Hct) levels. Additionally, renal samples were taken for histological evaluation.

Results

Ischemia-reperfusion significantly decreased the observed Hb and Hct values. The histopathological findings in the IR group confirmed that there was an increase in the hyaline cast and thickening of the Bowman capsule basement membrane. Treatment with EPO or MEL significantly increased the Hb and Hct values. In the MEL + IR group, the histopathological changes were lower than those found in the EPO + IR group.

Conclusions

Treatment with EPO and MEL had a beneficial effect on renal IR injury. The results may also indicate that MEL protects against morphological damage better than EPO in renal IR injury.