Soluble transferrin receptors and tissue oxygenation in non anaemic cystic fibrosis patients

Abstract 

Background

Chronic pulmonary disease and progressive tissue hypoxia are major causes of morbidity and mortality in cystic fibrosis (CF). Normally the body adapts to tissue hypoxia by increasing the red cell mass and decreasing the Hb-O₂ affinity. These adaptations are commonly observed in patients with cyanotic heart disease and individuals living at high altitude. However, patients with CF not only have an impaired erythroid response to hypoxia, but also are frequently anaemic.

Methods

In order to evaluate erythroid marrow activity and tissue oxygenation in 37 patients with CF we measured: the haematological and blood chemistry parameters; including red cell indices, ferritin, erythropoietin (Epo) and soluble transferrin receptors (sTfR) levels; arterial blood gases, P₅₀ and oxygen release to the tissues (O₂^R) and the 2,3-BPG levels.

Results

The main results showed that a) patients with CF have a mild degree of tissue hypoxia which is expressed by the moderately decreased of P₅₀ and O₂^R values and the relative increase of Epo level, b) 2,3-BPG synthesis in patients with CF is normal and c) sTfR levels are significantly increased (3-fold normal) in patients with CF compared to normal controls.

Conclusions

The above observations indicate that erythroid marrow activity in patients with CF is increased.

Keywords: Cystic fibrosis, Erythropoietin, Transferrin receptors