Insulin-like growth factor I: a modulator of erythropoiesis in uraemic patients?
Anaemia is a feature almost invariably complicating chronic renal failure. Its pathophysiology is multifactorial but the most important cause is erythropoietin (Epo) deficiency. However, either no relation or even a weakly positive relation generally exists between serum immunoreactive (i) Epo and haematocrit values in uraemic anaemia, whereas in anaemias of non-renal origin the correlation is most often strongly negative. Recent evidence indicates that growth hormone also stimulates erythropoiesis. Moreover, late erythroid progenitor cells (CFU-E) require insulin and/or insulin-like growth factor I (IGF-I) for development in vitro. IGF-I has been shown to have a synergistic action with Epo. We have measured serum iEpo and IGF-I levels in 17 haemodialysis patients with severe hyperparathyroidism (mean +/- SEM serum iPTH, 988 +/- 88 pg/ml). Mean age and duration of dialysis treatment were 46.1 +/- 3.4 and 8.8 +/- 1.0 years respectively. Mean haematocrit and haemoglobin values wer 28.1 +/- 1.7% and 9.39 +/- 0.54 g/dl respectively. Mean serum iEpo and IGF-I levels were 20.3 +/- 4.7 mU/ml and 320 +/- 20 ng/ml respectively (normal values for serum iEpo and IGF-I, 17.9 +/- 6 mU/ml and 91 +/- 23 ng/ml respectively). We found that serum IGF-I concentrations were well correlated with haematocrit values (r = 0.68, n = 15, P less than 0.004) whereas serum iEpo values were not (r = 0.41, n = 12, P = 0.18). IGF-I could therefore be an important factor regulating erythropoiesis in uraemic patients, at least when associated with severe hyperparathyroidism.
Ureña
P
P
Département de Néphrologie, Hôpital Necker-Enfants Malades, Paris, France.
Bonnardeaux
A
A
Eckardt
K U
KU
Kurtz
A
A
Drüeke
T B
TB
D000328:Adult; D000740:Anemia / Q000097:blood / Q000209:etiology; D004920:Erythropoiesis / Q000502:physiology*; D005260:Female; D006400:Hematocrit; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D014511:Uremia / Q000097:blood / Q000150:complications / Q000503:physiopathology*
D007334:Insulin-Like Growth Factor I