Vitamin D reduces COVID-19 complications – June 2021

Vitamin D attenuates COVID-19 complications via modulation of
    proinflammatory cytokines, antiviral proteins, and autophagy

Expert Rev Anti Infect Ther. 2021 Jun 10. doi: 10.1080/14787210.2021.1941871
Sadaf Jamal Gilani 1, May Bin-Jumah 2, Muhammad Shahid Nadeem 3, Imran Kazmi 3

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Article highlights

• Vitamin D is synthesized by the human skin cells under UVB radiation and activated in the liver and kidneys.
• Vitamin D deficiency has been positively linked with increased chances of infection, severity and mortality by respiratory infections including COVID-19.
• VRD-Vitamin D interaction results in the regulation of many genes associated with immune system and promotes the innate and adoptive immune response against respiratory infections.
• It enhances the production of antibacterial and anti-viral proteins including beta-defensins and cathelicidin to inhibit the cellular entry and subsequent proliferation of virus particles.
• In the macrophages, vitamin D promotes autophagy and clearance of virus particles by upregulation of calcium/nitric oxide, immunomodulatory proteins and downregulation of mTOR pathway.
• Future studies on anti-inflammatory, antiproleferative mechanisms involving vitamin D, development and application of appropriate animal models are recommended to combat COVID-19 or any upcoming similar pandemic.

Introduction: Global emergence of coronavirus disease-19 (COVID-19) has clearly shown variable severity, mortality, and frequency between and within populations worldwide. These striking differences have made many biological variables attractive for future investigations.
One of these variables, vitamin D, has been implicated in COVID-19 with rapidly growing scientific evidence.

Areas covered: The review intended to systematically explore the sources, and immunomodulatory the role of vitamin D in COVID-19. Search engines and data sources including Google Scholar, PubMed, NCBI, Scopus, and Web of Science were used for data collection. The search terms used were Vitamin D, COVID-19, immune system, antiviral mechanism. Overall, 232 sources of information were collected and 188 were included in this review.

Expert opinion: Interaction of vitamin D and vitamin D receptor (VDR), triggers the cellular events to modulate the immune system by regulation of many genes.
Vitamin D operates as a double-edged sword against COVID-19.

• First, in macrophages, it promotes the production of antimicrobial and antiviral proteins like β-defensin 2 and cathelicidin, these proteins inhibit the replication of viral particles and promote the clearance of virus from the cells by autophagy.
• Second, suppresses cytokine storm and inflammatory processes in COVID-19.