Melatonin, a hormone known primarily for regulating sleep, has emerged as a promising agent in the fight against viral, bacterial, and parasitic infections. This discovery offers hope for innovative treatments in the medical community. The motivation behind this research is to explore melatonin’s multifaceted role in immune response modulation, antioxidant activity, and potential therapeutic applications against a range of pathogens.

Dr. Georges Maestroni from the Center of Research in Medical Pharmacology at the University of Insubria led a comprehensive study examining melatonin’s influence on various infections. The findings were published in the peer-reviewed journal Biomolecules. Dr. Maestroni explored how melatonin, synthesized in the pineal gland and peripheral organs, can stimulate immune responses, reduce inflammation, and potentially act as a therapeutic agent against infections.

The study highlights melatonin’s dual role: its circadian action, which enhances immune responses, and its non-circadian effects, which provide antioxidant and anti-inflammatory benefits. This dual functionality may offer a balanced and effective immune response against microbial pathogens. “Melatonin’s ability to integrate its circadian and non-circadian functions is crucial for generating a robust immune response,” explained Dr. Maestroni.

Significant results were noted in various models of viral infections. For instance, melatonin demonstrated protective effects in mice infected with encephalomyocarditis virus and respiratory syncytial virus by reducing oxidative stress and inflammatory responses. During the COVID-19 pandemic, several studies investigated melatonin’s therapeutic potential, with mixed results. While some studies reported benefits such as reduced complications and mortality in severely ill patients, others found no significant effect on survival rates. Dr. Maestroni emphasized, “The wide array of doses and treatment schedules used in these studies perpetuates misconceptions about melatonin’s therapeutic properties.”

In bacterial infections, melatonin showed promise in improving outcomes in sepsis models. For example, it enhanced the survival of newborns with sepsis and improved bacterial clearance in mice infected with Staphylococcus aureus. Additionally, melatonin’s potential to combat antibiotic resistance was highlighted in studies involving tigecycline-resistant Klebsiella pneumoniae. It has to be  underlined that  antibiotic resistance is a serious worldwide health problem. The research underscored the need for a better understanding of melatonin’s dosing and administration schedules to maximize its therapeutic efficacy.

Regarding parasitic infections, melatonin exhibited protective effects against malaria and trypanosomiasis. In rodent models, melatonin improved immune responses and reduced parasitic loads. Notably, in cerebral malaria models, melatonin prevented brain damage and cognitive impairment. These findings suggest that melatonin could be a valuable adjunct therapy in managing parasitic infections.

The study concluded that while melatonin shows significant potential in combating infections, more research is needed to fully understand its mechanisms and optimize its therapeutic use. “The integration of melatonin’s immunoenhancing and anti-inflammatory actions could provide a powerful tool in the fight against infections,” stated Dr. Maestroni.

In summary, this research opens new avenues for exploring melatonin’s role beyond its traditional use in sleep regulation. By harnessing its immunomodulatory and antioxidant properties, melatonin could become a vital component in developing treatments for a variety of infectious diseases. Dr. Maestroni believes that future studies will be crucial in refining melatonin-based therapies and establishing standardized protocols for its clinical application.

Journal Reference

Maestroni, Georges J. M. “Role of Melatonin in Viral, Bacterial and Parasitic Infections.” Biomolecules, 2024, 14, 356. DOI: https://doi.org/10.3390/biom14030356

About the Author

Georges Maestroni, born in Lausanne , Switzerland in 1947,  graduated in Biology at the State University of Milan, Italy, in 1973.  In 1975, he joined the group of Prof. E. Sorkin at the Medizinisches Forschungsinstitut in Davos , Switzerland, where he started his research activity on the mutual relationship between the brain and the immune system. After a research stage in 1977  at the Weizmann Institute of Science in Rehovot, Israel, he worked  at the Anatomisches Institute of the University of Zürich where he stayed till 1981 when he moved to the Institute of Pathology of Locarno, Swsitzerland  where  he funded and directed the Center for Experimental Pathology  till 2008. Dr.Maestroni covers now the position of scientific  consultant of  the Center for Medical Pharmacology, at the University of Insubria, Varese, Italy.  In his career, Dr.Maestroni pioneered the studies about  the immunoenhancing role of melatonin as well as the sympathetic nervous system regulation of hematopoiesis.