Gitelman's and Bartter's Syndromes: From Genetics to the Molecular Basis of Hypertension and More.

Background: Gitelman's and Bartter's syndromes (GS/BS) are rare genetic tubulopathies characterized by electrolyte imbalance and activation of the renin-angiotensin-aldosterone system (RAAS). These syndromes have intriguing biochemical and hormonal abnormalities that lead them to be protected from hypertension and cardiovascular and renal remodeling.

Summary: In this review, we explore the biochemical/molecular mechanisms induced by the activation of the RAAS and its counterregulatory arm which is particularly activated in GS/BS patients, in the context of blood pressure regulation.

Rho Kinase Activity, Connexin 40, and Atrial Fibrillation: Mechanistic Insights from End-Stage Renal Disease on Dialysis Patients.

Evidence on cellular/molecular mechanisms leading to atrial fibrillation (AF) are scanty. Increased expression of Rho kinase (ROCK) and myosin-phosphatase-target subunit-1 (MYPT-1), ROCK activity's marker, were shown in AF patients, which correlated with connexin 40 (Cx40) expression, membrane protein of heart gap junctions, key for rapid action potential's cell-cell transfer. AF is the most frequent arrhythmia in dialysis patients who present increased MYPT-1 phosphorylation, which correlates with left ventricular (LV) mass.