ABSTRACT
Viral infections have been a cause of mortality for several centuries and continue to endanger the lives of many, specifically of the younger population. Vitamin D has long been recognized as a crucial element to the skeletal system in the human body. Recent evidence has indicated that vitamin D also plays an essential role in the immune response against viral infections and suggested that vitamin D deficiency increases susceptibility to viral infections as well as the risk of recurrent infections. For instance, low serum vitamin D levels were linked to increased occurrence of high burdens viral diseases such as hepatitis, influenza, Covid-19, and AIDS. As immune cells in infected patients are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D-deficient individuals with an infectious disease may extend beyond the impact on bone and calcium homeostasis. Even though numerous studies have highlighted the effect of vitamin D on the immune cells, vitamin D's antiviral mechanism has not been fully established. This paper reviews the recent mechanisms by which vitamin D regulates the immune system, both innate and adaptive systems, and reflects on the link between serum vitamin D levels and viral infections.
Subject(s)
Immunologic Factors/therapeutic use , Virus Diseases/therapy , Vitamin D Deficiency/therapy , Vitamin D/therapeutic use , Vitamins/therapeutic use , Betacoronavirus , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Coronavirus Infections/therapy , Dietary Supplements , Humans , Immune System , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/immunology , Pneumonia, Viral/therapy , SARS-CoV-2 , Virus Diseases/immunology , Virus Diseases/virology , Vitamin D/blood , Vitamin D Deficiency/immunology , Vitamin D Deficiency/virology , COVID-19 Drug TreatmentABSTRACT
While near-infrared spectroscopy (NIRS) haemodynamic measures have proven to be vastly useful in investigating human brain development, the haemodynamic response function (HRF) in infants is not yet fully understood. NIRS measurements of the oxidation state of mitochondrial enzyme cytochrome-c-oxidase (oxCCO) have the potential to yield key information about cellular oxygen utilisation and therefore energy metabolism. We used a broadband NIRS system to measure changes in oxCCO, in addition to haemodynamic changes, during functional activation in a group of 33 typically developing infants aged between 4 and 6 months. The responses were recorded over the right temporal lobe while the infants were presented with engaging videos containing social content. A significant increase in oxCCO was found in response to the social stimuli, with maximum increase of 0.238 ± 0.13 µM. These results are the first reported significant change in oxCCO in response to stimulus-evoked activation in human infants and open new vistas for investigating human infant brain function and its energy metabolism.