Renin-angiotensin system stimulates erythropoietin secretion in chronic hemodialysis patients.
A series of observations suggests an interrelationship between the renin-angiotensin system (RAS) and erythropoietin (EPO) secretion. To further evaluate the role of RAS in erythropoiesis of chronic hemodialysis patients, we studied two groups of such patients: Group A consisted of 16 patients (14 male and 2 female, 54.7 +/- 3.3 years old), who maintained a target hematocrit value of 0.30 (0.32 +/- 0.01), without recombinant human EPO (rhEPO) supplementation. Group B consisted of 14 patients (7 male and 7 female, 50 +/- 5.3 years old), who required subcutaneous injections of rhEPO (90.8 +/- 10 IU.kg-1.week-1), to maintain the same target hematocrit value of 0.30 (30 +/- 0.01). Plasma renin activity (PRA) was found to be the major feature to distinguish patients in these two Groups and it was five times higher in Group A (10 +/- 2 ng.ml-1.h-1) compared to Group B patients (1.8 +/- 0.6 ng.ml-1.h-1) (p < 0.001). Moreover, activation of RAS in Group A patients by volume depletion (2.2 +/- 0.2 l) during hemodialysis resulted in a 118 +/- 33 percent increment of PRA (p < 0.01) which was accompanied by a 69 +/- 25 percent increment of serum EPO levels (p < 0.05). Repetition of the same protocol after inhibiting the converting enzyme with 50 mg of Captopril prior to dialysis session, resulted in a 315 +/- 64 percent increment of PRA (p < 0.001), while at the same time completely blocked the expected rise in serum EPO levels (1.25 +/- 12.5 percent increment).(ABSTRACT TRUNCATED AT 250 WORDS)
Vlahakos
D V
DV
Division of Nephrology, University Hospital, Patras University School of Medicine, Rio, Greece.
Balodimos
C
C
Papachristopoulos
V
V
Vassilakos
P
P
Hinari
E
E
Vlachojannis
J G
JG
D004921:Erythropoietin / Q000378:metabolism* / Q000627:therapeutic use; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000627:therapeutic use; D006435:Renal Dialysis; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000502:physiology*
D011994:Recombinant Proteins; D004921:Erythropoietin; D012083:Renin