Dhondt A, Vanholder R, Van Biesen W, Lameire N
Renal Division, Department of Medicine, University Hospital of Gent, Gent, Belgium.
Kidney Int Suppl. 2000 Aug;76:S47-59. doi: 10.1046/j.1523-1755.2000.07606.x.
Three major groups of uremic solutes can be characterized: the small water-soluble compounds, the middle molecules, and the protein-bound compounds. Whereas small water-soluble compounds are quite easily removed by conventional hemodialysis, this is not the case for many other molecules with different physicochemical characteristics. Continuous ambulatory peritoneal dialysis (CAPD) is often characterized by better removal of those compounds. Urea and creatinine are small water-soluble compounds and the most current markers of retention and removal, but they do not exert much toxicity. This is also the case for many other small water-soluble compounds. Removal pattern by dialysis of urea and creatinine is markedly different from that of many other uremic solutes with proven toxicity. Whereas middle molecules are removed better by dialyzers containing membranes with a larger pore size, it is not clear whether this removal is sufficient to prevent the related complications. Larger pore size has virtually no effect on the removal of protein-bound toxins. Therefore, at present, the current dialytic methods do not offer many possibilities to remove protein-bound compounds. Nutritional and environmental factors as well as the residual renal function may influence the concentration of uremic toxins in the body fluids.
小分子水溶性化合物、中分子物质和蛋白结合化合物。小分子水溶性化合物很容易通过传统血液透析清除，但许多具有不同物理化学特性的其他分子并非如此。持续性非卧床腹膜透析（CAPD）的特点通常是能更好地清除这些化合物。尿素和肌酐是小分子水溶性化合物，也是目前衡量潴留和清除情况的最常用指标，但它们的毒性不大。许多其他小分子水溶性化合物也是如此。尿素和肌酐的透析清除模式与许多其他已证实具有毒性的尿毒症溶质明显不同。中分子物质通过孔径较大的透析膜的透析器能得到更好的清除，但这种清除是否足以预防相关并发症尚不清楚。较大的孔径对蛋白结合毒素的清除几乎没有影响。因此，目前现有的透析方法在清除蛋白结合化合物方面没有太多办法。营养和环境因素以及残余肾功能可能会影响体液中尿毒症毒素的浓度。
