Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of Amyloidosis
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Case Reports
Benefit of doxycycline treatment on articular disability caused by dialysis related amyloidosis.
Abstract Doxycycline inhibits amyloid formation in vitro and its therapeutic efficacy is under evaluation in clinical trials for different protein conformational diseases, including prion diseases, Alzheimer's disease and transthyretin amyloidosis. In patients on chronic hemodialysis, a persistently high concentration of β2-microglobulin causes a form of amyloidosis (dialysis-related amyloidosis, DRA) localized in bones and ligaments. Since doxycycline inhibits β2-microglobulin fibrillogenesis in vitro and accumulates in bones, DRA represents an ideal form of amyloidosis where doxycycline may reach a therapeutic concentration at the site of amyloid deposition. ⋯ Plasmatic levels of the drug reached a plateau after one week (1.1-2.3 µg/ml). Treatment was well tolerated in two patients for a year, while one was suspended after 5 months due to mild esophagitis. Treatment was associated with a significant reduction in articular pain and with a significant and measurable improvement in passive and active movements in all cases, despite the persistence of unchanged amyloid deposits measured by magnetic resonance imaging.
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Abstract The clinical phenotype of familial ATTR amyloidosis depends to some extent on the particular mutation, but differences exist also within mutations. We have previously described that two types of amyloid fibril compositions exist among Swedish ATTRV30M amyloidosis patients, one consisting of a mixture of intact and fragmented ATTR (type A) and one consisting of mainly intact ATTR (type B). The fibril types are correlated to phenotypic differences. ⋯ No clear conclusions could be drawn about a phenotype to fibril type correlation among ATTR non-V30M patients. In contrast, Japanese ATTRV30M patients showed a similar correlation as previously described for Swedish ATTRV30M patients. This study shows that a fibril composition with fragmented ATTR is very common in ATTR amyloidosis, and suggests that fibrils composed of only full-length ATTR is an exception found only in a subset of patients.