Dialysis related amyloidosis: a disease of chronic retention and inflammation?

Dialysis related amyloidosis (DRA) has become a major complication of long-term therapy in chronic hemodialysis or peritoneal dialysis patients. DRA is characterized by the presence of beta 2-microglobulin (beta 2m) in the amyloid fibrils. The pathogenesis of DRA is incompletely understood, but most likely is based on the uremic retention of beta 2m. In contrast, current evidence does not favor a significant role of an enhanced beta 2m synthesis rate in uremic patients. Apart from the beta 2m retention, posttranslational modification of the molecule also seems to be an important step in the amyloidogenesis, since, in addition to intact beta 2m, fragmented beta 2m or beta 2, with altered isoelectric properties can be detected in the DRA fibrils. The occurrence of these beta 2m species could be linked to a chronic intermittent stimulation of monokine release or other subclinical inflammatory processes during renal replacement therapy. Thus, it is possible that, as a consequence of repeated cellular activation, protease release and/or intracellular processing of beta 2m occurs. Renal transplantation has been shown to arrest the further progression of DRA. However, since transplantation is not feasible for a significant number of patients, non-transplant strategies to prevent DRA also need to be evaluated. Some, but not all, retrospective studies on DRA associated symptomatology in patients on chronic hemodialysis with high flux membranes have suggested a lesser prevalence in these patients as compared to patients treated with standard cellulosic membranes. To further clarify this issue and to test whether non-transplant therapies indeed may play a role in the prevention of DRA, prospective studies will be needed.(ABSTRACT TRUNCATED AT 250 WORDS)