Hyperparathyroidism and Anemia in Uremic Subjects

Abstract

Abstract. Several factors are involved in conditioning renal anemia, and a critical role is attributed to parathyroid hormone (PTH) oversecretion, which has some direct effects on endogenous erythropoietin (EPO) synthesis, bone marrow erythroid progenitors, and red cell survival. Indirect effects are mainly based on the induction of bone marrow fibrosis. Indirect evidence of the role of PTH is based on the observation that parathyroidectomy, when performed in uremic patients, is often followed by restoration of the hematocrit. The interpretations of such positive results are based on the observation of the restored bone marrow space after operation and also in a rise of immunoreactive EPO serum concentrations observed in the first weeks after gland removal. Another field of clinical interest is the possible beneficial effects of vitamin D therapy in controlling PTH secretion, which in turn determines an improvement of anemia of uremic subjects. Several uncontrolled studies confirmed this possibility, indicating that patients who respond to calcitriol or its analogs also show an increase of their hemoglobin levels. Thus, a combined therapeutic approach to PTH oversecretion and anemia is possible by intravenous calcitriol or parathyroidectomy pointing to the possible reversibility of bone marrow fibrosis, which is a common feature of secondary hyperparathyroidism. The increased sensitivity to EPO therapy can also induce a successful reduction of its dosage, thus allowing an interesting reduction of costs.

Correlation Between Levels of 25-Hydroxy-Vitamin D and Degree of Anemia in Patients with Chronic Kidney Disease

“…The beneficial effects of vitamin D in controlling PTH hypersecretion could produce an improvement in the anemia of renal patients [25]. In our work, however, a correlation between 25(OH)D and PTH levels was not found, either with intact-or bio-PTH.…”

“…Some authors also point to an important role of PTH hypersecretion in renal anemia, which would have direct effects on endogenous EPO synthesis, bone marrow progenitors, and red cell survival [25]. The beneficial effects of vitamin D in controlling PTH hypersecretion could produce an improvement in the anemia of renal patients [25].…”

Management of Anemia in Children Receiving Chronic Peritoneal Dialysis

“…[16][17][18][19] Proposed mechanisms include direct effects of PTH on bone marrow progenitor cells, endogenous erythropoietin synthesis and erythrocyte survival, as well as an indirect effect via stimulation of bone marrow fibrosis. 20 According to our findings, these effects become clinically relevant at PTH levels .500 pg/ml. Induction of bone marrow fibrosis is also considered the mechanism underlying the marked ESA resistance observed in this and previous studies in patients with ESRD caused by the metabolic storage disorders cystinosis and oxalosis.…”

Individual Response Variations to Erythropoietin Stimulating Agents in Patients on Maintenance Hemodialysis.

“…It is evident that hyperparathyroidism diminishes endogenous Epo synthesis, reduces bone marrow erythroid progenitors, and shortens erythrocyte survival [71]. The higher iPTH suppressed the calcitriol receptor activity on the red cell surface, resulting in the deficiency of active vitamin D leading to the reduced releasing of endogenous Epo, reducing the sensitivity of peripheral tissue towards Epo, thus resulting in the Epo resistance.…”