Low serum levels of prohepcidin, but not hepcidin-25, are related to anemia in familial amyloidosis TTR V30M.

Familial amyloidosis TTR V30M (FAP-I) usually presents as a sensorimotor and autonomic neuropathy. Anemia was first described in this disease more than 20 years ago and classified as an anemia of chronic disease. However, so far no studies have addressed the role of inflammatory proteins in this disease. The anemia affects 24.8% of symptomatic FAP-I Portuguese patients, and is associated with low serum erythropoietin levels, independently of the presence of clinical nephropathy. In this study we evaluate the role of systemic inflammation on the erythropoietin production and anemia genesis in FAP-I. Data from 24 FAP-I patients (50% with anemia) and 33 healthy controls were analysed. Laboratory data included hemoglobin, hematocrit, ferritin, transferrin saturation, soluble transferrin receptors (sTR), prohepcidin, hepcidin-25, C-reactive protein (CRP), interleukin-6 and erythropoietin levels. In general, FAP-I patients presented significantly lower hemoglobin, hematocrit and observed/expected erythropoietin levels. Mean sTR was lower in FAP-I patients than in controls (2.36+/-1.3 vs 2.96+/-0.8 mg/l, P=0.055) correlating with hemoglobin and hematocrit. As expected, sTR were positively correlated with erythropoietin both in controls and in FAP-I patients. No significant differences on CRP, interleukin-6, transferrin saturation, ferritin and hepcidin-25 were found between anemic and non-anemic FAP-I patients and between non-anemic FAP-I patients and healthy controls. In all groups, a positive correlation was observed between hepcidin-25 and ferritin. Surprisingly, significantly lower prohepcidin levels were found in FAP-I patients, with or without anemia, not correlated with serum hepcidin-25 levels. In general, the decreased observed/expected EPO levels in FAP-I correlated with the prohepcidin levels, therefore raising the possibility that a common defect in these two hormones may be somehow involved in the genesis of the disease.

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.

Kidney and anemia in familial amyloidosis type I.

BACKGROUND: Familial amyloid polyneuropathy (FAP) type I is caused by a mutated transthyretin (TTR V30M) and characterized by a sensorimotor and autonomic neuropathy. Renal, cardiac, and ocular abnormalities can also occur. Anemia has been described in previous reports, but its prevalence in Portuguese FAP patients is not precisely known. The aim of this study was to estimate the prevalence of anemia in FAP type I Portuguese patients and to evaluate the contribution of erythropoietin (Epo) to its genesis. METHODS: A retrospective cross-sectional study was undertaken to determinate the prevalence and characteristics of anemia in 165 FAP patients. For comparison analysis, 3 control groups were also evaluated, 1 group of 46 apparently healthy subjects, 1 group of 17 asymptomatic carriers of FAP-trait, and a group of 14 non-FAP patients with chronic renal insufficiency. Serum Epo levels were analyzed in all groups. RESULTS: Anemia was present in 24.8% of symptomatic FAP patients. Iron stores, B12 vitamin, and serum folate levels were normal. FAP patients presented significantly lower serum Epo levels than healthy controls (P= 0.003). Epo levels were found lower than expected for the degree of anemia and in 17.5% were undetectable. Low Epo values were observed independently of the presence of renal failure or anemia, and sometimes preceded clinical disease. CONCLUSION: Anemia in FAP type I is a common manifestation. The results clearly suggest a defective endogenous Epo production in the genesis of the anemia.