SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

Some sodium, potassium and water changes in the elderly and their treatment

reatinine clearance decreases with age by 1 ml/min/year after 40 years of age, although serum creatinine remains constant because of reduction of muscle mass. Reduction of water intake may occur in the elderly because of a reduced sensation of thirst; this is associated with a tendency to lose water with urine. The capacity to respond to sodium load is impaired in aged kidneys, thereby leading to ECV expansion and hypertension. But there is also, in the elderly, a reduced capacity for retaining sodium (FENa is higher than in young subjects), making old subjects sensitive to salt depletion and ECV contraction. Hypernatraemia (Nas > 150 mmol/l) is not infrequent in the elderly (1%) and is usually due to water deficiency (old subjects should be forced to drink), and rarely to iatrogenic excess of sodium. It is the abrupt occurrence of severe hypernatraemia that causes neurological symptoms due to dehydration and brain shrinking, which may lead to cerebral haemorrhage and death. Hyponatraemia (Nas 10%, and is due to water retention in an attempt to normalize ECV. Hypervolaemic hyponatraemia is due to ADH hypersecretion because of a decrease in 'effective' circulating blood volume. 'Pseudohyponatraemia' may occur because of hyperlipidaemia or hyperproteinaemia. It is the abrupt occurrence of severe hyponatraemia that causes neurological symptoms (water intoxication), secondary to the oedomatous swelling of the brain within the skull. While rapidly occurring hyponatraemia may be lethal, slowly occurring hyponatraemia is usually asymptomatic. Rapid correction of hyponatraemia may cause cerebral dehydration and 'osmotic demyelination syndrome' ('central pontine myelinosis'). Decrease (e.g. by diuretics) or increase (e.g. by ACE-inhibitors, non-steroidal anti-inflammatory drugs, beta-blockers) or serum potassium may occur in the elderly. Diuretics should be used with caution in elderly subjects to avoid salt depletion, hypotension and renal function impairment

Loop diuretics and renal vasodilators in acute renal failure

Loop diuretics are powerful drugs able to increase urinary sodium and water excretion even in conditions of marked impairment of renal function. Loop diuretics are useful in preventing or ameliorating the course of acute renal failure. This effect may be obtained when they are used within 18 h after the ischaemic and/or toxic event. Loop diuretics reduce tubular work, providing resistance to cellular ischaemia. Other important beneficial effects include tubular wash-out of cellular debris and inhibition of tubuloglomerular feedback. Among vasodilators, dopamine, when used at 'dopaminergic dosage' is useful in preventing acute renal failure. Its efficacy is demonstrated in several situations of renal hypoperfusion, i.e. salt depletion, cyclosporin administration, and therapy with recombinant interleukin 2 in cancer patients. According to our studies it appears that dopamine should be used in the early phases of acute renal failure to improve renal perfusion, re-establish glomerular filtration rate, and increase tubular flow