Genetics of hypertension

In the past year, substantial progress has been made in both mapping and fine mapping the genes involved in blood pressure regulation. Genome scans have been carried out in humans and mice and these reveal many new potential chromosomal locations for blood pressure susceptibility loci. The chromosomal regions containing blood pressure genes for many of the inbred hypertensive rat models have been refined using new congenic strains. Further genetic studies support a role for antiotensinogen, aldosterone synthase and a region close to the epithelial sodium channel in blood pressure regulation. Finally, comprehensive single-nucleotide polymorphism analysis of cardiovascular genes has been undertaken using chip technology.     

Diabetes and hypertension

Diabetes mellitus and hypertension constitute two powerful independent risk factors for cardiovascular, renal and atherosclerotic disease. The frequent occurrence of the two diseases in the same individual doubles the risk of cardiovascular death, as well as substantially increasing the frequency of transient ischemic attacks, strokes, peripheral vascular disease with lower extremity amputations, as well as end-stage renal disease and blindness. Although hypertension usually occurs in IDDM in association with renal disease, in NIDDM the evolution of hypertension appears to be multifactorial and independent of renal disease. Obesity appears to be dissociable from hypertension and NIDDM with a common link between obesity, hypertension and NIDDM appearing to be hyperinsulinism and insulin resistance. It has been suggested that hyperinsulinism and insulin resistance may lead to hypertension through altered intracellular calcium metabolism, enhanced renal sodium reabsorption, or through an effect of insulin upon lipid and/or catecholamine metabolism. Further, insulin itself may have a direct effect upon the atherosclerotic process in the hypertensive diabetic patient. These considerations have been taken into account in the structuring of antihypertensive therapy in Type I and Type II Diabetes Mellitus.     

Nutrition and hypertension

There has been a good deal of interest in the relation of nutrition to cardiovascular diseases and this is likely to continue. We consider recent research developments concerned with the well known examples of the association of high salt intake with hypertension and of saturated fats with atherosclerosis. Some of the difficulties encountered in the investigation of dietary factors in hypertension are similar to those encountered in the investigation of dietary factors in atherosclerosis and coronary heart disease. Much additional research, which takes into account the multifactorial nature of cardiovascular disease, is needed to determine the effects of diet on the development and treatment of these diseases.