Receptor mineralocorticoide extrarrenal. Una posible nueva diana para combatir el daño vascular / Extrarenal mineralocorticoid receptor. A potential new target against vascular damage

El receptor mineralocorticoide (MR) y su principal ligando la aldosterona juegan un papel fundamental en la regulación de la presión arterial a través de sus efectos facilitadores de la reabsorción de sodio y agua. Los antagonistas del receptor de la aldosterona son fármacos de probada eficacia, que en la actualidad se utilizan en pacientes seleccionados con hipertensión arterial resistente. Además, estos fármacos aumentan la supervivencia en diversas circunstancias como en la insuficiencia cardiaca, proporcionan protección renal en pacientes con enfermedad renal crónica y tienen efectos beneficiosos adicionales en otras patologías. Más allá de sus efectos cardiorrenales, en la actualidad sabemos que el MR se expresa en otros tejidos como células musculares lisas y endoteliales vasculares mediando efectos deletéreos tales como remodelado vascular, rigidez vascular y disfunción endotelial, los cuales son factores pronósticos de futuros eventos cardiovasculares. Además, nuevas evidencias experimentales demuestran que el MR se expresa también en células adyacentes a la vasculatura como células inmunes y adipocitos a través de los cuales podría influir en la función y estructura vascular. Entre los mecanismos responsables de dichos efectos se incluyen mecanismos genómicos y no genómicos, que facilitan la producción de especies reactivas de oxígeno de distintas fuentes, entre las que destaca la enzima NADPH oxidasa, así como de otros mediadores inflamatorios. En este artículo se revisan las evidencias experimentales y clínicas que sugieren que la activación del MR por aldosterona es un importante mediador de daño vascular a través de la producción de especies reactivas de oxígeno

Mineralocorticoid receptor (MR) and its main ligand aldosterone, play a key role in the regulation of blood pressure through their effects increasing sodium and water reabsorption. MR antagonists are effective drugs that are currently used in selected patients with resistant hypertension. In addition, these drugs increase patients survival in specific circumstances such as heart failure, they offer renal protection in chronic kidney disease patients and they have beneficial effects in other pathologies. Besides MR cardiorenal effects, it is now accepted that MR is expressed in other tissues and cells such as vascular smooth muscle cells and endothelial cells where excessive MR activation induces deleterious effects such as vascular remodeling and stiffness and endothelial dysfunction, which are prognostic factors for future cardiovascular events. Moreover, novel evidence demonstrate that MR is also expressed in non-vascular cells adjacent to vessels such as immune cells and adipocytes that might influence vascular function and structure. Among the mechanisms responsible for these effects of MR are genomic and non genomic mechanisms that facilitate reactive oxygen species production mainly from the NADPH oxidase enzyme, as well as production of other inflammatory mediators. Here we review the experimental and clinical evidence that suggest that MR activation by aldosterone is an important mediator of vascular damage through the production of reactive oxygen species

Tubular overexpression of gremlin induces renal damage susceptibility in mice.

A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-ß. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1) specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-ß and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage progression. This transgenic mouse model could be used as a new tool for enhancing the knowledge of renal disease progression.