Effect of exogenous erythropoietin on haem synthesis in anaemic patients with rheumatoid arthritis.
The effect of recombinant human erythropoietin (rHuEPO) on haem biosynthesis in peripheral red blood cells was evaluated in 12 patients with RA and anaemia (mean haemoglobin concentration 102 g/l, range 90-109 g/l). Before treatment, the serum concentrations of erythropoietin (EPO) were low (mean 13 pmol/l, range 5-32 pmol/l), the activities of haem-synthesizing enzymes within the reference intervals and the erythrocyte protoporphyrin (E-PROTO) concentrations clearly higher than normal. Nine patients responded with an increase in the haemoglobin level of 15 g/l or more. rHuEPO induced a rise in the mean haem synthase (HAEM-S) activity from a baseline of 12.1 to a maximum of 26.8 pmol/h per 10(6) reticulocytes after 20 weeks of treatment (P < 0.002). The mean E-PROTO concentration also rose and reached its maximum at 8 weeks of treatment. We conclude that correction of anaemia in patients with RA using rHuEPO is associated with an activation of HAEM-S, commonly regarded as the rate-limiting enzyme of haem synthesis in erythroid cells. Functional iron deficiency probably explains the simultaneous rise in E-PROTO concentration.
Pettersson
T
T
Fourth Department of Medicine, Helsinki University Central Hospital, Finland.
Rosenlöf
K
K
Laitinen
E
E
Tenhunen
R
R
D000328:Adult; D000368:Aged; D000740:Anemia / Q000097:blood* / Q000150:complications / Q000628:therapy; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000150:complications; D004912:Erythrocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006418:Heme / Q000096:biosynthesis*; D006454:Hemoglobins / Q000032:analysis / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011524:Protoporphyrins / Q000032:analysis
D006454:Hemoglobins; D011524:Protoporphyrins; D004921:Erythropoietin; D006418:Heme