Ca++ and 1,25(OH)2D3 regulate in vitro and in vivo the response to human recombinant erythropoietin in CAPD patients.
In vitro studies indicate that the culture medium Ca++ concentration conditions the response to erythropoietin of bone marrow erythropoietic cells which also have specific receptors for 1,25(OH)2D3. We therefore evaluated in 12 anemic CAPD patients: 1) in vitro with increasing concentrations of Ca++ alone or Ca++ plus 1,25(OH)2D3 a) Ca++ in the bone marrow erythroid cell cytoplasm; b) colony (BFU-E and CFU-E) growth from bone marrow erythroid cells. 2) in vivo before and after 24 weeks of i.v. recombinant human erythropoietin (rHuEPO) therapy a) bone marrow erythroid cell cytoplasmic Ca++; b) BFU-E and CFU-E growth. Results showed that in CAPD patients, in vitro cytoplasmic Ca++ in bone marrow erythroid cells, and BFU-E and CFU-E growth were lower than in normals and the addition of Ca++ caused a dose-dependent increase; 1,25(OH)2D3) potentiated these effects; 2, in vivo rHuEPO therapy normalized the aforementioned parameters. An inverse relationship was seen between the bone marrow erythorid cell cytoplasmic Ca++ levels before therapy and the duration of therapy necessary to correct anemia. These data underline the role of Ca++ and 1,25(OH)2D3 in erythropoiesis in uremic patients and may aid the understanding of the mode of action and the degree of response to rHuEPO in CAPD patients.
Carozzi
S
S
Nephrology and Dialysis Unit, St. Paul's Hospital, Savona, Italy.
Ramello
A
A
Nasini
M G
MG
Schelotto
C
C
Caviglia
P M
PM
Cantaluppi
A
A
Salit
M
M
Lamperi
S
S
D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D002117:Calcitriol / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D015672:Erythroid Precursor Cells / Q000502:physiology*; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D011994:Recombinant Proteins / Q000627:therapeutic use
D011994:Recombinant Proteins; D004921:Erythropoietin; D002117:Calcitriol; D002118:Calcium