Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 3 de 3
Med Sci (Paris) ; 38(1): 89-95, 2022 Jan.
Article in French | MEDLINE | ID: covidwho-1642032


Melatonin is a naturally occurring molecule derived from tryptophan. Melatonin is a key player in relaying the circadian rhythm between our environment and our body. It has also a key role in rhythming the seasons (more production during long nights and less during short ones) as well as in the reproduction cycles of the mammals. Melatonin is often and surprisingly presented as a molecule with multiple therapeutic properties that can fix (or help to fix) many health issues, such as diseases (cancer, ageing, virus-induced affections including COVID-19, etc…) or toxicological situations (metals, venoms, chemical such as adriamycin [doxorubicin], methotrexate or paclitaxel). The mechanistics behind those wonders is still missing and this is puzzling. In the present commentary, the main well-established biological properties are presented and briefly discussed with the aim of delineating the borders between facts and wishful thinking.

Title: Mélatonine - Petit précis à l'usage des trop enthousiastes. Abstract: La mélatonine est une molécule naturelle dérivée du tryptophane. Son rôle est de servir de relai entre la rythmicité jour/nuit et notre corps. Elle sert donc de marqueur circadien : concentration haute pendant la nuit et basse pendant la journée. Elle sert aussi de marque saisonnière : plus les nuits sont longues et plus longuement elle est produite (et vice-versa), ce qui a un rôle primordial dans les cycles reproductifs des animaux. Mais elle est aussi affublée de multiples propriétés thérapeutiques concernant la plupart des maladies humaines, du cancer à la COVID-19 en passant par l'infection par le virus Ebola, ainsi que de capacités thérapeutiques vis-à-vis de multiples toxicités (métaux, venins, produits chimiques comme l'adriamycine [doxorubicine], le méthotrexate ou le paclitaxel). Alors que l'enthousiasme à propos de cette molécule est troublant, l'assise scientifique de ces descriptions est dans le meilleur des cas faible et dans la plupart des cas, inexistante. Dans ce commentaire, les données scientifiques bien établies liées à la mélatonine sont résumées et brièvement discutées, en tâchant de redessiner les limites entre ce qui est connu et bien établi et ce qui reste du domaine du fantasme.

Circadian Rhythm/drug effects , Communication , Melatonin/pharmacology , Melatonin/physiology , Animals , COVID-19/drug therapy , Humans , Melatonin/therapeutic use , Reproducibility of Results , Seasons
Biomolecules ; 10(8)2020 08 07.
Article in English | MEDLINE | ID: covidwho-823584


Neurodegenerative diseases are the second most common cause of death and characterized by progressive impairments in movement or mental functioning in the central or peripheral nervous system. The prevention of neurodegenerative disorders has become an emerging public health challenge for our society. Melatonin, a pineal hormone, has various physiological functions in the brain, including regulating circadian rhythms, clearing free radicals, inhibiting biomolecular oxidation, and suppressing neuroinflammation. Cumulative evidence indicates that melatonin has a wide range of neuroprotective roles by regulating pathophysiological mechanisms and signaling pathways. Moreover, melatonin levels are decreased in patients with neurodegenerative diseases. In this review, we summarize current knowledge on the regulation, molecular mechanisms and biological functions of melatonin in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, vascular dementia and multiple sclerosis. We also discuss the clinical application of melatonin in neurodegenerative disorders. This information will lead to a better understanding of the regulation of melatonin in the brain and provide therapeutic options for the treatment of various neurodegenerative diseases.

Circadian Rhythm , Melatonin/physiology , Neurodegenerative Diseases/metabolism , Oxidative Stress , Alzheimer Disease/metabolism , Amyotrophic Lateral Sclerosis/metabolism , Animals , Circadian Rhythm/drug effects , Dementia, Vascular/metabolism , Humans , Huntington Disease/metabolism , Melatonin/therapeutic use , Multiple Sclerosis/metabolism , Neurodegenerative Diseases/drug therapy , Oxidative Stress/drug effects , Parkinson Disease/metabolism
Front Endocrinol (Lausanne) ; 11: 622, 2020.
Article in English | MEDLINE | ID: covidwho-805179


The origin of the coronavirus disease 2019 (COVID-19) pandemic is zoonotic. The circadian day-night is the rhythmic clue to organisms for their synchronized body functions. The "development for mankind" escalated the use of artificial light at night (ALAN). In this article, we tried to focus on the possible influence of this anthropogenic factor in human coronavirus (HCoV) outbreak. The relationship between the occurrences of coronavirus and the ascending curve of the night-light has also been delivered. The ALAN influences the physiology and behavior of bat, a known nocturnal natural reservoir of many Coronaviridae. The "threatened" and "endangered" status of the majority of bat species is mainly because of the destruction of their proper habit and habitat predominantly through artificial illumination. The stress exerted by ALAN leads to the impaired body functions, especially endocrine, immune, genomic integration, and overall rhythm features of different physiological variables and behaviors in nocturnal animals. Night-light disturbs "virus-host" synchronization and may lead to mutation in the genomic part of the virus and excessive virus shedding. We also proposed some future strategies to mitigate the repercussions of ALAN and for the protection of the living system in the earth as well.

Chiroptera/physiology , Coronavirus Infections/epidemiology , Lighting , Pneumonia, Viral/epidemiology , Animals , COVID-19 , Ecosystem , Environment , Humans , Light , Melatonin/physiology , Pandemics