Please cite this paper as:

Ahmed, M. 2020. Avoiding room light during night may stimulate immunity in COVID-19 patients by promoting melatonin production. Melatonin Research. 3, 4 (Oct. 2020), 476-481. DOI:https://doi.org/https://doi.org/10.32794/mr11250073.


Commentary

Avoiding room light during night may stimulate immunity in COVID-19 patients by promoting melatonin production

Murtada Ahmed Adam Ali

Sudanese National Council for Medical and Health Professionals, Khartoum, Sudan

Correspondence: murtadadams.q@gmail.com, Tel: +249915016794

Running title: Light at night with melatonin and COVID-19

Received: July 14, 2020; Accepted: September 3, 2020

 

ABSTRACT

     COVID-19 is one of the greatest health issues facing humankind for many decades; it emerged in Wuhan, China, late in December 2019, and rapidly spread over the world within the short period. This report emphasizes the potential hazards of exposure to room light at night which affects the immunity of COVID-19 patients by suppressing their melatonin, which is only released from the pineal gland at night. Exposure to light at night is especially common in the hospital setting. This may make the symptom worse for the hospitalized patients and the light at night should not be ignored. Thus, I suggest that COVID-19 patients should avoid light at night either by wearing eye masks or darkening the room to enhance pineal melatonin synthesis and increase their serum melatonin levels.

 

Key words: COVID-19, melatonin, light-inhibition, immunity, eye masks, darkness.

______________________________________________________________________________

 

     COVID-19 infection is a serious condition which has led to the death of hundreds of thousands of people worldwide. While many drugs have been repurposed as potential treatments for this serious disease, none are efficacious to the point where they have become the “standard of care” (1, 2).  Thus, there is an intensive search for molecules that will prevent or reduce the severity and mortality of this infectious disease which continues to ravage the population of many countries.  One molecule that has been repeatedly suggested as a likely effective agent to treat COVID-19 is melatonin (3-8). Melatonin is a potent antioxidant and anti-inflammatory agent (9, 10), features which would likely make it useful in the treatment of COVID-19.  A preliminary study of the use of melatonin as a treatment for this viral infection has proven its effectiveness reducing the severity of COVID-19 (11), limiting hospitalization and the necessity for intubation, which often leads to serious complications.

     According to the World Health Organization (WHO), COVID-19 patients should be hospitalized for a period of two weeks; accordingly, they are often exposed to night lighting throughout the treatment period. It is known that people with a reduced immune response are more susceptible to COVID-19 infections compared to those with normal immunity. In the absence of a vaccine, stimulating the immune system of these patients may be an appropriate solution to reduce the recovery period or limit the severity of the disease. This narrative suggests enhancement of patients’ immunity during their stay in hospital by preserving their naturally endogenous melatonin secretion by blocking night illumination (12).

     Melatonin (N-acetyl-5-methoxytryptamine) is a secretory product of the pineal gland which is primarily produced in a circadian pattern under the influence of the suprachiasmatic nucleus (SCN) located in the hypothalamus (13, 14). In mammals including humans, melatonin synthesis and secretion is stimulated during darkness and inhibited by light (15-17). Many studies have clearly documented the important role of melatonin and its positive effect on the immune system by enhancing circadian rhythms which, in turn, are linked to many central nervous system diseases, e.g., sleep disorders and seasonal affective disorder, etc. (18-21). In addition, numerous studies have confirmed that melatonin regulates the sleep wake cycle which is also important, in modulating the immune system responses as well as core body temperature, etc. (22-24). Melatonin regulates multiple aspects in immune responses by stimulating the production of lymphocytes, granulocytes, macrophages and NK cells (25, 26). Melatonin is a potent antioxidant which helps the immune system to fight invading viruses and an anti-inflammatory agent by subside inflammation (27-30). The comprehensive roles of melatonin in assisting humans to resist diseases is still under intense investigation.

    Many studies have demonstrated that night time melatonin secretion is suppressed when light is detected by the retina (31, 32). The influence of light on the SCN/pineal/melatonin system has been extensively studied and well established, i.e., exposure to the artificial light at night causes disturbance of melatonin production (33-35). The production of melatonin by the pineal gland increases during the night and light after darkness onset is an acute melatonin suppressor (36-38). Melatonin synthetic suppression is especially sensitive to shorter wavelengths of light (blue) as opposed to longer wavelengths (39-42). Moreover, studies have also shown that melatonin suppression depends on the light intensity, i.e., the higher the light intensity, the lower the melatonin production is (43-46). Blood melatonin concentrations are highest during the mid-dark phase and being minimal levels during the light phase of the light/dark cycle (47-49). Consequently, protection from artificial light at night has become of interest to many researchers. Studies have shown that if night time illumination is shielded from the patients in the intensive care units (ICU) it preserves higher levels of circulating melatonin for these patients (50, 51).

     In conclusion, melatonin plays an important role in the immune system and its production at night will be suppressed by light. The room light illumination at night will negatively affect COVID-19 patients by suppressing their melatonin production. The night time increased melatonin is important to enhance their immune system to improve their defense against viral infection, vis verse.  Thus, this report suggests that COVID-19 patients should avoid exposure to room light at night either by wearing sleep eye masks or darkening the room to enhance the synthesis and release of pineal melatonin. This seems a minor measure, but it may have significant effects to improve COVID-19 patients’ immune response against virus and reduce severity and mortality (52).

 

ACKNOWLEDGEMENT

     None.

 

CONFLICT OF INTEREST

     No conflict of interest.


REFERENCES

 

  1. Cheng F, et al. (2020) COVID-19 treatment: combining anti-inflammatory and antiviral therapeutics using a network-based approach. Cleveland Clinic. J. Med. 2020: doi.10.3949/ccjm.87a.ccc037.

  2. Anderson G, Reiter RJ. (2020) COVID-19 pathophysiology: interactions of gut microbiome, melatonin, vitamin D, stress, kynurenine and the alpha 7 nicotinic receptor: treatment implications. Melatonin Res. 3 (3): 322–345. doi:10.32794/mr11250066.

  3. Dominguez-Rodriguez A, et al. (2020) Melatonin, cardiovascular disease and COVID-19: A potential therapeutic strategy. Melatonin Res. 3 (3): 318–321., doi:10.32794/mr11250065.

  4. Hardeland R, Tan DX (2020) Protection by melatonin in respiratory diseases: valuable information for the treatment of COVID-19. Melatonin Res. 3 (3): 264–275. doi:10.32794/mr11250061.

  5. Tan DX, Hardeland R (2020) Estimated doses of melatonin for treating deadly virus infections: Focus on COVID-19. Melatonin Res. 3 (3): 276–296. doi:10.32794/mr11250062.

  6. Cardinali DP (2020) High doses of melatonin as a potential therapeutic tool for the neurologic sequels of Covid-19 infection. Melatonin Res. 3 (3): 311–317. doi:10.32794/mr11250064.

  7. Banerjee A, et al. (2020) Crosstalk between endoplasmic reticulum stress and anti-viral activities: A novel therapeutic target for COVID-19. Life Sci. 255: 117842. doi.10.1016/j.lfs.2020.117842.

  8. Tan DX, et al. (2012) Mitochondria and chloroplasts as the original sites of melatonin synthesis: a hypothesis related to melatonin's primary function and evolution in eukaryotes. J. Pineal Res. 54 (2): 127–138., doi.10.1111/jpi.12026.

  9. Boga, JA, Coto-Montes A (2020) ER stress and autophagy induced by SARS-CoV-2: The targets for melatonin treatment. Melatonin Res. 3(3) :346–361. doi.10.32794/mr11250067.

  10. Reiter RJ, et al. (2017) Melatonin as a mitochondria-targeted antioxidant: One of evolution’s best ideas. Cell. Mo. Life Sci. 74 (21): 3863–3881. doi.10.1007/s00018-017-2609-7.

  11. Castillo RR, et al. (2020) Melatonin as adjuvant treatment for coronavirus disease 2019 pneumonia patients requiring hospitalization (MAC-19 PRO): a case series. Melatonin Res. 3 (3): 297–310. doi:10.32794/mr11250063.

  12. Grivas TB, Savvidou OD (2007) Melatonin the ‘light of night’ in human biology and adolescent idiopathic scoliosis. Scoliosis 2 (6): doi.10.1186/1748-7161-2-6.

  13. Brzezinski A (1997) Melatonin in humans. New Engl. J. Med. 336 (3): 186-195. doi:10.1056/nejm199701163360306.

  14.  Zhao D, Yu Y, Shen Y, Liu Q, Zhao Z, Sharma R, Reiter RJ (2019) Melatonin synthesis and function: Evolutionary history in animals and plants. Front. Endocrinol. 10: Doi.10.3389/fendo.2019.00249.

  15. Zeitzer JM, Duffy JF, Lockley SW, Dijk D-J, Czeisler CA. (2007) Plasma melatonin rhythms in young and older humans during sleep, sleep deprivation, and wake. Sleep 30 (11): 1437–1443. Doi. 10.1093/sleep/30.11.1437.

  16. Masters A, Pandi-Perumal SR, Seixas A, Girardin JL, McFarlane SI (2014) Melatonin, the hormone of darkness: From sleep promotion to ebolatreatment. Brain Disord. Ther. 4 (1): 1000151. Doi. 10.4172/2168-975X.1000151.

  17. Ostrin LA (2018) Ocular and systemic melatonin and the influence of light exposure. Clin. Exp. Optom. 102 (2): 99–108. doi:10.1111/cxo.12824.

  18. Burgess HJ, Sletten T, Savic N, Gilbert SS, Dawson D (2001) Effects of bright light and melatonin on sleep propensity, temperature, and cardiac activity at night. J. Appl. Physiol. 91 (3): 1214–1222. doi: 10.1152/jappl.2001.91.3.1214.

  19. Cajochen C, et al. (2003) Role of melatonin in the regulation of human circadian rhythms and sleep. J. Neuroendocrinol. 15 (4):  432–437. doi:10.1046/j.1365-2826.2003.00989.x.

  20. Mila MM, Bruce JN (2004) Human pineal physiology and functional significance of melatonin. Front. Neuroendocrinol. 25 (3-4): 177–195., doi:10.1016/j.yfrne.2004.08.001.

  21. Zisapel N (2018) New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. Bri. J. Pharmacol. 175 (16): 3190–3199. doi:10.1111/bph.14116.

  22.  Nelson RJ, Demas GE (1997) Role of melatonin in mediating seasonal energetic and immunologic adaptations. Brain Res.  Bull. 44 (4): 423–430. doi: 10.1016/s0361-9230(97)00222-0.

  23.  Cho Y, Ryu S-H, Lee BR, Kim KH, Lee E, Choi J (2015) Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment. Chronobiol. Int. 32 (9): 1294–1310. doi: 10.3109/07420528.2015.1073158.

  24. TouitouY, ReinbergA, Touitou D (2017) Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption. Life Sci. 173: 94–106. doi: 10.1016/j.lfs.2017.02.008.

  25. Carrillo-Vico A, Guerrero JM, Lardone PJ, Reiter RJ (2005) A review of the multiple actions of melatonin on the immune system. Endocrine 27 (2): 189–200. doi: 10.1385/endo:27:2:189.

  26.  Calvo JR, González-Yanes C, Maldonado MD (2013) The role of melatonin in the cells of the innate immunity: a review.  J.  Pineal Res. 55 (2): 103–120. doi: 10.1111/jpi.12075.

  27. Vinther AG (2015) The influence of melatonin on immune system and cancer. Int.  J.  Cancer Clin.  Res. 2 (4): doi: 10.23937/2378-3419/2/4/1024.

  28. Mortezaee K, Potes Y, Mirtavoos-Mahyari H, Motevaseli E, Shabeeb D, Musa AE, Farhood B (2019) Boosting immune system against cancer by melatonin: A mechanistic viewpoint. Life Sci. 238: 116960. doi: 10.1016/j.lfs.2019.116960.

  29. Reiter RJ, Calvo JR, Karbownik M, Qi W, Tan DX (2006) Melatonin and its relation to the immune system and inflammation. Ann. N. Y. Acad.   Sci. 917 (1): 376–386. doi: 10.1111/j.1749-6632.2000.tb05402.x.

  30. Tarocco A, Caroccia N, Morciano G, Wieckowski MR, Ancora G, Garani G, Pinton P (2019) Melatonin as a master regulator of cell death and inflammation: molecular mechanisms and clinical implications for newborn care. Cell Death Dis. 10 (4): doi: 10.1038/s41419-019-1556-7.

  31. Brainard GC, et al. (2011) Action spectrum for melatonin regulation in humans: Evidence for a novel circadian photoreceptor. J. Neurosci. 21: (16):  6405–6412. doi:10.1523/jneurosci.21-16-06405.2001.

  32. Glickman G, et al. (2003) Inferior retinal light exposure is more effective than superior retinal exposure in suppressing melatonin in humans. J. Biol. Rhythms 18 (1): 71–79. doi:10.1177/0748730402239678.

  33.  Reiter RJ, Tan DX, KorkmazA, Erren TC, Piekarski C, Tamura H, Manchester LC (2007) Light at night, chronodisruption, melatonin suppression, and cancer risk: A review. Crit.  Rev. Oncogenesis 13 (4): 303-328. doi:10.1615/critrevoncog.v13.i4.30.

  34. Chellappa SL, Steiner R, Blattner P, Oelhafen P, Götz T, Cajochen C (2011) Non-visual effects of light on melatonin, alertness and cognitive performance: Can blue-enriched light keep us alert? PLoS ONE 6 (1): doi: 10.1371/journal.pone.0016429.

  35. Grubisic M, Haim A, Bhusal P, Dominoni DM, Gabriel KM, Jechow A, Hölker F (2019) Light pollution, circadian photoreception, and melatonin in vertebrates. Sustainability 11 (22): 6400. doi:10.3390/su11226400.

  36. Lewy A, Wehr T, Goodwin F, Newsome D, Markey S (1980) Light suppresses melatonin secretion in humans. Science 210 (4475): 1267–1269. doi: 10.1126/science.7434030.

  37. Higuchi S, Nagafuchi Y, Lee S-I, Harada T (2014) Influence of light at night on melatonin suppression in children.  J. Clin. Endocrinol. Metab. 99 (9): 3298–3303. doi: 10.1210/jc.2014-1629.

  38. Tähkämö L, et al. (2018) Systematic review of light exposure impact on human circadian rhythm. Chronobiol. Int. 36 (2): 151–170. doi:10.1080/07420528.2018.1527773.

  39. Lewy AJ (1983) Effects of light on human melatonin production and the human circadian system. Prog. Neuropsychopharmacol. Biol. Psychiatry 7 (4-6): 551–556. doi: 10.1016/0278-5846(83)90024-6.

  40. Wright HR, Lack L C (2001) Effect of light wavelength on suppression and phase delay of the melatonin rhythm. Chronobiol.  Int. 18(5): 801–808. doi: 10.1081/cbi-100107515.

  41. Kayumov L, Casper RF, Hawa RJ, Perelman B, Chung SA, Sokalsky S, Shapiro CM (2005) Blocking low-wavelength light prevents nocturnal melatonin suppression with no adverse effect on performance during simulated shift work. J. Clin .Endocrinol. Metab. 90 (5): 2755-2761. doi:10.1210/jc.2004-2062.

  42. Kozaki T, Kubokawa A, Taketomi R, Hatae K (2015) Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night. J. Physiol. Anthropol. 34 (1): doi: 10.1186/s40101-015-0067-1.

  43. Claustrat B, Brun J, Geoffriau M, Chazot G, Challarmel M (1997) Melatonin, sleep-wake cycle and sleep. Biol. Psychiatry 42 (1): doi:10.1016/s0006-3223(97)87830-4.

  44. Nathan P (1999) Melatonin sensitivity to dim white light in affective disorders. Neuropsychopharmacology 21 (3): 408-413.doi:10.1016/s0893-133x (99)00018-4.

  45. Aubé M, Roby J, Kocifaj M (2013) Evaluating potential spectral impacts of various artificial lights on melatonin suppression, photosynthesis, and star visibility. PLoS ONE 8 (7): doi: 10.1371/journal.pone.0067798.

  46. Kozaki T, et al. (2014) Effects of different light intensities in the morning on dim light melatonin onset. J.  Physiol. Anthropol. 30 (3): 97–102. doi:10.2114/jpa2.30.97.

  47. Arendt J (1998) Melatonin and the pineal gland: influence on mammalian seasonal and circadian physiology. Rev. Reprod. 3 (1): 13–22. doi: 10.1530/ror.0.0030013.

  48.  Touitou Y (2001) Human aging and melatonin. Clinical relevance. Exp. Gerontol. 36 (7): 1083–1100. doi: 10.1016/s0531-5565(01)00120-6.

  49. Gooley JJ, Chamberlain K, Smith KA, Khalsa SB, Rajaratnam SM, Reen EV, Lockley SW (2011) Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. Endocrinology 152 (2): 742-742. doi:10.1210/endo.152.2.zee742.

  50. Hu RF, et al. (2010) Effects of earplugs and eye masks on nocturnal sleep, melatonin and cortisol in a simulated intensive care unit environment. Crit. Care 14 (2): doi:10.1186/cc8965.

  51. Huang HW, et al. (2015) Effect of oral melatonin and wearing earplugs and eye masks on nocturnal sleep in healthy subjects in a simulated intensive care unit environment: Which might be a more promising strategy for ICU sleep deprivation? Crit.  Care 19 (1) 124. doi:10.1186/s13054-015-0842-8.

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