[Vascular damage in chronic renal failure. The increase of vascular nitrotyrosine and cytochines accumulation is accompanied by an increase of endothelial nitric oxide synthase (eNOS) expression]. / Daño vascular en la insuficiencia renal crónica. El aumento de depósitos vasculares de nitrotirosina y citocinas se acompaña de una elevación de la expresión vascular de la óxido nítrico sintasa endotelial (eNOS).

Patients with chronic renal failure (CRF) are at a greatly increased risk of cardiovascular mortality. This fact could be due to the presence of conventional risk factor and specific uremic as increase of oxidative stress, hyperhomocystaenemia, deranged calcium-phosphate metabolism and chronic inflammatory state. In order to analyze the vascular effects of CRF, we studied the histomorphometric characteristics (intima-media thickness and monocyte chemoattractant protein (MCP-1) accumulation (inmunohistochemical) on radial artery from 13 patients with CRF. We determined by Western blot analysis, the vascular nitrotyrosin abundance (footprint of nitric oxide (NO) inactivation by reactive oxygen species (ROS), and the endothelial nitric oxide synthase (eNOS) expression. The NOS activity was, also, determined. The results were compared with those obtained in pudenda artery from a healthy control group (n: 16). The CRF group showed a significant increase in intima and media thickness 108 +/- 16 vs 14 +/- 2.5 microm, p < 0.001 and 291 +/- 19 vs 153 +/- 15 microm, p < 0.001, respectively). The CRF group exhibited a marked elevation of MCP-1 vascular expression (2 +/- 0.15 vs 0.6 +/- 0.12 u, p < 0.001). A significant positive correlation was found between MCP-1 vascular expression and its inmunohistochemical deposits (r: 0.98, p < 0.0001). Nitrotyrosin abundance (western blot) was significantly increased in artery of CRF patients (2.1 +/- 0.1 vs 0.42 +/- 0.1 u, p < 0.0001). No significant differences was found in NOS activity between CRF and control groups. However, eNOS expression was greatly increased in the CRF patients (1.73 +/- 0.1 vs 0.67 +/- 0.1 u, p < 0.001). A significant positive correlation was found between nitrotyrosin and eNOS expression and systolic arterial pressure. However, the differences between CRF and control groups persisted after statistically fitting to arterial pressure. The present study demonstrate that in CRF there are arterial preatherosclerotic changes and an increase of vascular nitrotyrosin accumulation, which is the footprint of NO inactivation by ROS. The secondary NO inactivation can, in turn, contribute to eNOS vascular upregulation.

Daño vascular en la insuficiencia renal crónica. El aumento de depósitos vasculares de nitrotirosina y citocinas se acompaña de una elevación de la expresión vascular de la óxido nítrico sintasa endotelial (eNOS) / Vascular damage in chronic renal failure. The increase of vascular nitrotyrosine and cytochines accumulation is accompanied by an increase of endothelial nitric oxide synthase (ENOS) expression

La insuficiencia renal crónica (IRC) se acompaña de un aumento de la morbimortalidadcardiovascular debido a la concurrencia de factores de riesgo cardiovasculartradicionales y otros factores inherentes a la uremia como estrés oxidativo,hiperhomocisteinemia, anomalías del metabolismo fosfocálcico, anemia yfenómenos inflamatorios entre otros.Para analizar la repercusión vascular de la IRC, en este trabajo se hace un estudiohistomorfométrico (grosor íntima-media) y de los depósitos vasculares (inmuno-histoquímica) de la proteína quimiotáctica de monocitos (MPC-1) de la arteriaradial en 13 sujetos con IRC, Se determinan, también, la expresión vascular(western blot) de nitrotirosina (marcador del efecto de especies reactivas de oxígeno(ROS) sobre el óxido nítrico (ON), de la MCP-1 (citocina con efecto aterogénico)y de la óxido nítrico sintasa endotelial (eNOS), y la actividad de la NOS.Los hallazgos se comparan con los observados en la arteria pudenda, arteria muscularde las mismas características que la radial, en un grupo control sano (n: 16),de edad y sexo similares a los enfermos.El grosor de la íntima y de la media fue mayor en los enfermos (íntima 108 ±16 vs 14 ± 2,5 µ, p < 0,001; media: 291 ± 19 vs 153 ± 15 µ, p < 0,001). La expresiónvascular de la MCP-1 en los enfermos fue más elevada que en los controles(2 ± 0,15 vs 0,6 ± 0,12 u, p < 0,001). La expresión de la proteína se correlacionócon los depósitos inmunohistoquímicos de la misma (r: 0,98, p <0,0001). Las arterias de los enfermos con IRC tenían mayor expresión de nitrotirosinaque las de los sujetos sanos (2,1 ± 0,1 vs 0,42 ± 0,1 u, p < 0,0001). Noexistieron diferencias significativas en la actividad de la NOS entre los dos grupos.La expresión de la eNOS, sin embargo, fue significativamente más elevada enlos enfermos con IRC (1,73 ± 0,1 vs 0,67 ± 0,1 u, p < 0,001). La expresión dela nitrotirosina y de la eNOS se correlacionó directamente con la presión arterial sistólica. No obstante, las diferencias entre los grupos persistieron tras los ajustesa los valores de presión arterial.Estos resultados demuestran que en la IRC, a nivel de la arteria radial, existencambios preaterosclerosos, y un aumento de los depósitos de nitrotirosina, marcadordel efecto de ROS sobre el ON. Secundariamente a la disminución de labioactividad del ON, se produce un aumento compensador de la expresión vascularde la eNOS

Patients with chronic renal failure (CRF) are at a greatly increased risk of cardiovascularmortality. This fact could be due to the presence of conventional riskfactor and specific uremic as increase of oxidative stress, hyperhomocystaenemia,deranged calcium-phosphate metabolism and chronic inflammatory state.In order to analyce the vascular effects of CRF, we studied the histomorphometriccharacteristics (intima-media tickness and monocyte chemoattractant protein(MCP-1) accumulation (inmunohistochemical) on radial artery from 13 patientswith CRF. We determined by Western blot analysis, the vascular nitrotyrosinabundance (footprint of nitric oxide (NO) inactivation by reactive oxygen species(ROS), and the endothelial nitric oxide synthase (eNOS) expression. The NOS activitywas, also, determined. The results were compared with those obtained inpudenda artery from a healthy control group (n: 16).The CRF group showed a significant increase in intima and media tickness 108± 16 vs 14 ± 2,5 µ, p < 0,001 and 291 ± 19 vs 153 ± 15 µ, p < 0,001, respectively).The CRF group exhibited a marked elevation of MCP-1 vascular expression(2 ± 0,15 vs 0,6 ± 0,12 u, p < 0,001). A significant positive correlationwas found between MCP-1 vascular expression and its inmunohistochemical deposits(r: 0,98, p < 0,0001). Nitrotyrosin abundance (western blot) was significantlyincreased in artery of CRF patients (2,1 ± 0,1 vs 0,42 ± 0,1 u, p < 0,0001).No significant differences was found in NOS activity between CRF and controlgroups. However, eNOS expression was greatly increased in the CRF patients(1,73 ± 0,1 vs 0,67 ± 0,1 u, p < 0,001). A significant positive correlation wasfound between nitrotyrosin and eNOS expression and systolic arterial pressure.However, the differences between CRF and control groups persisted after statisticallyfitting to arterial pressure.The present study demonstrate that in CRF there are arterial preatheroscleroticchanges and an increase of vascular nitrotyrosin accumulation, wich is the footprintof NO inactivation by ROS. The secondary NO inactivation can, in turn, contributeto eNOS vascular upregulation

Regulation of aquaporin mRNA expression in rat kidney by water intake.

Three aquaporins (AQP) are present in the membrane of the principal collecting duct cells. On the apical side, the levels of AQP2 protein are increased in response to both arginine vasopressin and water deprivation. However, whether this change parallels changes in the abundance of AQP3 and AQP4 in the basolateral membrane is less well known. This study evaluates the effect of either dehydration or water loading on the rat kidney mRNA expression of AQP2, AQP3, and AQP4. Poly(A+)RNA was prepared from renal cortex and medulla of control, water-deprived, well hydrated, and water-deprived rats treated with OPC31260, a V2 receptor antagonist. Northern blots were done and mRNA levels were quantified using a PhosphorImager system. Relative to control, water deprivation increased the expression of cortical AQP2, -3, and -4, whereas water loading decreased the cortical and medullar expression of AQP2, -3, and -4. Therefore, in addition to AQP2 and -3, AQP4 expression is also regulated by water intake. Treatment with OPC31260 (40 mg/kg of weight per d) inhibited up to 20 to 30% the upregulation of AQP-mRNA induced by water deprivation. Blood values of arginine vasopressin and aldosterone were significantly increased by water deprivation, whereas they were unchanged by water overloading. Taken together, these results indicate that renal AQP2, -3, and -4 expression is regulated in a coordinated manner. Simultaneous up- or downregulation of the three transcripts occurred upon either water deprivation or water loading of animals, respectively. However, the signaling mechanism for the two long-term adaptive processes may be different, and, in addition to arginine vasopressin, other factors may be involved in the transcriptional regulatory processes.