Myocardial infarction and viral triggers: what do we know by now?

Myocardial infarction (MI) is an acute clinical manifestation ischaemic heart disease, which is the leading cause of death worldwide. Infections also have an important burden worldwide, with lower respiratory infections being the worldwide leading cause of death due to communicable diseases. The relationship of MI with viral respiratory infections (including influenza and SARS-CoV-2) as a trigger has been well documented with significant associations. These infections can lead to Type 1 MI, where inflammation and vascular dysfunction, as well as the increased prothrombotic environment lead to atherothrombosis. Type 2 MI may also occur due to an imbalance of oxygen/blood supply and myocardial demand (hypoxaemia, fever, and tachycardia). The data from randomized controlled trials showing a potential benefit of influenza vaccination in coronary artery disease patients should not be ignored. This can be considered a further argument for the association of viral infections (influenza in particular) and MI.

Vitamin D-related polymorphisms and vitamin D levels as risk biomarkers of COVID-19 disease severity.

Vitamin D is a fundamental regulator of host defences by activating genes related to innate and adaptive immunity. Previous research shows a correlation between the levels of vitamin D in patients infected with SARS-CoV-2 and the degree of disease severity. This work investigates the impact of the genetic background related to vitamin D pathways on COVID-19 severity. For the first time, the Portuguese population was characterized regarding the prevalence of high impact variants in genes associated with the vitamin D pathways. This study enrolled 517 patients admitted to two tertiary Portuguese hospitals. The serum concentration of 25 (OH)D, was measured in the hospital at the time of patient admission. Genetic variants, 18 variants, in the genes AMDHD1, CYP2R1, CYP24A1, DHCR7, GC, SEC23A, and VDR were analysed. The results show that polymorphisms in the vitamin D binding protein encoded by the GC gene are related to the infection severity (p = 0.005). There is an association between vitamin D polygenic risk score and the serum concentration of 25 (OH)D (p = 0.04). There is an association between 25 (OH)D levels and the survival and fatal outcomes (p = 1.5e-4). The Portuguese population has a higher prevalence of the DHCR7 RS12785878 variant when compared with its prevalence in the European population (19% versus 10%). This study shows a genetic susceptibility for vitamin D deficiency that might explain higher severity degrees in COVID-19 patients. These results reinforce the relevance of personalized strategies in the context of viral diseases.Trial registration: NCT04370808.