Liver transplantation and anemia in familial amyloidosis ATTR V30M

Familial amyloid polyneuropathy type I (FAP-I) is caused by a mutant transthyretin (TTR V30M) produced by liver, and orthotopic liver transplantation (OLT) is a widely accepted treatment for stopping the major production of TTR V30M. Anemia affects 24.8% of symptomatic FAP-I patients with low erythropoietin (Epo) levels, suggesting a blockage of Epo-producing cells by local or circulating factors. To evaluate the putative toxicity effect of the mutant protein on Epo-producing cells and consequent Epo production, clinical and laboratory parameters of 20 FAP patients were collected before and after liver transplantation, analyzed and compared. Following OLT, the prevalence of anemia increased, with a significant decrease in transferrin saturation, but without significant change in ferritin. Serum Epo levels remained low after OLT and the observed to expected (O/E) Epo level ratio decreased even further after OLT (O/E < 0.8 rose to 70%). Despite the decrease in creatinine clearance (95.1 to 66.9 ml/min, p < 0.001), a similar median O/E Epo level was observed, independently of the presence of renal failure, excluding an important impact of renal failure on Epo production. The increase of anemia after OLT and the maintenance of a defective endogenous Epo production after liver transplantation excluded an inhibitory effect of the circulating TTR V30M on the Epo-producing cells.