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Many experimental studies have obtained a prolonged control of blood pressure through gene treatment. This consists in the administration of genes coding for vasodilator proteins (the ‘sense’ approach), or of nucleotide sequences that are complementary to the mRNA of vasoconstrictor proteins, which are consequently synthesized in smaller amounts (the ‘antisense’ approach). Examples of the sense approach include the genes encoding endothelial nitric oxide synthase and kallikrein. Examples of the second type of approach are the antisense oligodeoxynucleotides to angiotensin-converting enzyme and endothelin-1. Also, RNA molecules, such as ribozymes and small interfering RNAs, are capable to inhibit RNA function. Whole sense genes are usually administered through viral vectors, while antisense oligonucleotides may be administered with plasmids or liposomes. Both viral and non-viral vectors have advantages and disadvantages. Despite the still persisting limitations, the possibility exists that in the future some forms of genetic treatment will be extended to the clinical setting, allowing a prolonged control of essential hypertension and its end-organ sequelae.

An important role in atherogenesis is played by oxidative stress, which may be induced by common risk factors. Mitochondria are both sources and targets of reactive oxygen species, and there is growing evidence that mitochondrial dysfunction may be a relevant intermediate mechanism by which cardiovascular risk factors lead to the formation of vascular lesions. Mitochondrial DNA is probably the most sensitive cellular target of reactive oxygen species. Damage to mitochondrial DNA correlates with the extent of atherosclerosis. Several cardiovascular risk factors are demonstrated causes of mitochondrial damage. Oxidized low density lipoprotein and hyperglycemia may induce the production of reactive oxygen species in mitochondria of macrophages and endothelial cells. Conversely, reactive oxygen species may favor the development of type 2 diabetes mellitus, mainly through the induction of insulin resistance. Similarly - in addition to being a cause of endothelial dysfunction, reactive oxygen species and subsequent mitochondrial dysfunction - hypertension may develop in the presence of mitochondrial DNA mutations. Finally, other risk factors, such as aging, hyperhomocysteinemia and cigarette smoking, are also associated with mitochondrial damage and an increased production of free radicals. So far clinical studies have been unable to demonstrate that antioxidants have any effect on human atherogenesis. Mitochondrial targeted antioxidants might provide more significant results.

In both animal models and humans, increased blood pressure has been associated with oxidative stress in the vasculature, i.e. an excessive endothelial production of reactive oxygen species (ROS), which may be both a cause and an effect of hypertension. In addition to NADPH oxidase, the best characterized source of ROS, several other enzymes may contribute to ROS generation, including nitric oxide synthase, lipoxygenases, cyclo-oxygenases, xanthine oxidase and cytochrome P450 enzymes. It has been suggested that also mitochondria could be considered a major source of ROS: in situations of metabolic perturbation, increased mitochondrial ROS generation might trigger endothelial dysfunction, possibly contributing to the development of hypertension. However, the use of antioxidants in the clinical setting induced only limited effects on human hypertension or cardiovascular endpoints. More clinical studies are needed to fully elucidate this so called "oxidative paradox" of hypertension.

During the last few years the studies on the genetic basis of essential hypertension (EH) have been numerous, allowing however only a partial understanding of the underlying molecular mechanisms. The most used techniques were the candidate gene approach, genome-wide scanning, the intermediate phenotype approach and comparative-genomics in animal models.The renin-angiotensin-aldosterone system may play a prominent role in the genesis of hypertension, and polymorphisms of the genes coding for angiotensinogen, angiotensin-converting enzyme, angiotensin II type I and 2 receptors, and aldosterone synthase have been widely studied. Other mechanisms may involve the KLK I gene of tissue kallikrein, gene variants of endothelial nitric oxide synthase and polymorphisms of the endothelin- 1 gene. Finally, a number of studies have highlighted the potential contribution of polymorphisms of genes coding for inflammatory cytokines, adrenergic receptors and intracellular G proteins, which can activate Na+/K+ exchangers. Further important information might derive from proteomic analysis and the study of mitochondrial genome. Overall, results have often been discordant, sometimes suggesting a different expression of the same gene variants in different populations. EH is a highly polygenic condition, caused by the combination of small changes in the expression of many genes, in conjunction with a variable collection of environmental factors.

Since endothelial dysfunction may significantly contribute to the pathophysiology of hypertension and its complications, its modification seems to be a very attractive means to favourably affect the development of atherosclerosis and cardiovascular events in hypertensive patients. However, not all antihypertensive drugs consistently improve endothelial dysfunction. While first-generation beta-blockers showed contrasting or null effects on endothelial function, newer beta-blockers of the third generation, such as carvedilol and nebivolol, seem to be provided with specific endothelium-mediated vasodilating effects. Calcium channel blockers are generally able to increase endothelium-dependent vasodilation in several vascular beds, in patients with essential hypertension, probably through multiple mechanisms. Most studies have shown thatACE inhibitors favourably affect endothelial function mainly in the subcutaneous, epicardial and renal circulation, not only by inhibiting the effects of angiotensin II on the endothelium, but also by enhancing bradykinin-induced vasodilation, probably a hyperpolarization-related effect. On the other hand, discordant evidence is available about the effects of angiotensin II receptor type I blockers on endothelial function in patients with essential hypertension, atherosclerosis or diabetes.There are data suggesting that an increased activity of the endothelin- I system may play a role in the blunted endothelium-dependent vasorelaxation of hypertensive patients, an effect that could be contrasted by the use of endothelin-I receptor antagonists. However, to date no substantial clinical efficacy of endothelin-I receptor blockers has been shown in patients with essential hypertension. Finally, other possibly useful compounds in restoring impaired endothelial function in hypertension are some antioxidant agents such as vitamin C, folic acid, the cofactor tetrahydrobiopterin (BH4), L-arginine and the drugs of the statin class.