Servicio de Nefrologia, Hospital Privado de Cordoba, Universidad Catolica de Cordoba, Cordoba, Argentina.
Nephrol Dial Transplant. 2011 Dec;26(12):4142-5. doi: 10.1093/ndt/gfr533. Epub 2011 Sep 22.
The water channel aquaporin-1 (AQP1) is the molecular counterpart of the ultrasmall pore that mediates free water transport during peritoneal dialysis (PD). Proof-of-principle studies performed in rats have shown that treatment with corticosteroids upregulates the expression of AQP1 in the peritoneal capillaries, causing a significant increase in free water transport. Whether such a beneficial effect could be observed in end-stage renal disease patients treated by PD remains unknown. Peritoneal transport parameters were evaluated in three patients on PD, shortly before and after living-donor renal transplantation and treatment with high-dose methylprednisolone (1.0-1.2 g/m(2)). As compared with pre-transplantation values, the post-transplantation test revealed an ∼2-fold increase in the sodium sieving and ultrasmall pore ultrafiltration volume, suggesting an effect on AQP1 water channels. In contrast, there was no change in the parameters of small solute transport. The direct involvement of AQP1 in these changes is suggested by the expression of glucocorticoid receptors in the human peritoneum and the presence of conserved glucocorticoid response elements in the promoter of the human AQP1 gene.
水通道蛋白 aquaporin-1（AQP1）是介导腹膜透析（PD）期间游离水转运的超小孔的分子对应物。在大鼠中进行的原理验证研究表明，皮质类固醇治疗可上调腹膜毛细血管中 AQP1 的表达，导致游离水转运显著增加。在接受 PD 治疗的终末期肾病患者中是否可以观察到这种有益作用尚不清楚。在 3 名 PD 患者中，在活体供肾移植和高剂量甲基强的松龙（1.0-1.2 g/m²）治疗前后，评估了腹膜转运参数。与移植前值相比，移植后试验显示钠筛和超小孔超滤量增加了约 2 倍，提示对 AQP1 水通道有影响。相比之下，小分子转运参数没有变化。人类腹膜中存在糖皮质激素受体，以及人类 AQP1 基因启动子中存在保守的糖皮质激素反应元件，这表明 AQP1 直接参与了这些变化。
