Current clinical aspects of dialysis-related amyloidosis in chronic dialysis patients

The current understanding of dialysis-related amyloidosis has evolved over the past two decades. In the early 1980s, several researchers found amyloid deposits in the synovia of carpal tunnel syndrome (CTS), which have been recognized as a complication of chronic hemodialysis. The enigma was resolved in 1985, when beta2-microglobulin (beta2-m) with a molecular weight of 12,000 Da was identified as the major constitutional protein of this amyloid. Amyloid fibrils of this type that contain the sub-unit protein of human leukocyte antigens (HLA), beta2-m, deposit predominantly in osteoarticular tissues, inducing musculoskeletal symptoms such as CTS, polyarthralgia, bone cyst showing radiolucency at X-ray examination and destructive spondyloarthropathy. In addition, extra articular symptoms such as ischemic colitis, megaloglossia, and heart failure, that is, systemic involvement occasionally occur. We confirmed that the prevalence of CTS increases with duration of dialysis. Most patients with CTS associated with beta2-m amyloid deposits have undergone hemodialysis for 10 years or more. Up to 50% of patients had developed this complication after 20 years and the percentage was even higher after 25 years. General categories of therapeutic approaches for amyloidosis include prevention of onset or progression, symptomatic therapy (conservative treatment, orthopedic procedures, and physiotherapy), and renal transplantation. It is critical to elucidate the detail mechanisms of the amyloid fibril formation, and establish its radical treatment. It is also important to develop novel therapies such as cell implantation to compensate for normal kidney functions of uremic toxin protein metabolism.