Stroke, high blood pressure and the Renin-Angiotensin-aldosterone system - new developments

The AT1/AT2 Receptor Equilibrium Is a Cornerstone of the Regulation of the Renin Angiotensin System beyond the Cardiovascular System

The AT₁ receptor has mainly been associated with the pathological effects of the renin-angiotensin system (RAS) (e.g., hypertension, heart and kidney diseases), and constitutes a major therapeutic target. In contrast, the AT₂ receptor is presented as the protective arm of this RAS, and its targeting via specific agonists is mainly used to counteract the effects of the AT₁ receptor. The discovery of a local RAS has highlighted the importance of the balance between AT₁/AT₂ receptors at the tissue level. Disruption of this balance is suggested to be detrimental. The fine tuning of this balance is not limited to the regulation of the level of expression of these two receptors. Other mechanisms still largely unexplored, such as S-nitrosation of the AT₁ receptor, homo- and heterodimerization, and the use of AT₁ receptor-biased agonists, may significantly contribute to and/or interfere with the settings of this AT₁/AT₂ equilibrium. This review will detail, through several examples (the brain, wound healing, and the cellular cycle), the importance of the functional balance between AT₁ and AT₂ receptors, and how new molecular pharmacological approaches may act on its regulation to open up new therapeutic perspectives.

Aldosterone synthase gene (CYP11B2) -344C/T polymorphism contributes to the risk of recurrent cerebral ischemia

BACKGROUND

Accumulating evidence suggests that CYP11B2 rs1799998 (-344C/T) polymorphism is independently associated with an increased risk of stroke. Our aim was to determine whether -344C/T also predisposes to recurrent cerebral ischemia following in patients with symptomatic intracranial atherosclerosis disease (ICAD).

METHODS

Genotypes of the CYP11B2 -344C/T polymorphism were determined by polymerase chain reaction-restriction fragment length polymorphism. A total of 208 ICAD patients were enrolled and underwent a long-term clinical follow-up to detect the recurrent cerebral ischemia.

RESULTS

During a median follow-up time of 35 months, 40 recurrent strokes (19.2%) were documented. Kaplan-Meier and multivariable Cox regression analyses adjusted for age, gender, and other cardiovascular risk factors identified that the presence of the TT genotype within the CYP11B2 -344C/T polymorphism was associated with an increased risk of 1.98-fold for recurrent cerebral ischemia (the hazard ratio 1.98, 95% confidence interval 1.16-3.41; p=0.01).

CONCLUSIONS

Our findings suggest that the -344C/T polymorphism of the CYP11B2 gene confers an increased risk of recurrent cerebral ischemia.