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Clinica Chimica Acta, 65 (1975) 389-392 0 Elsevier Scientific Publishing Company,
Amsterdam
- Printed
in The Netherlands
SHORT COMMUNICATIONS CCA 7404
THE ERYTHROCYTE
K. VLASSOPOULOS,
PROTOPORPHYRIN
K. MELISSINOS
IN CHRONIC RENAL FAILURE
and G. DRIVAS
Department of Pathologic Physiology, School of Medicine, University of Athens, Athens 609 (Greece) (Received
July 2, 1975)
Summary
The erythrocyte protoporphyrin concentration in 63 patients suffering from chronic renal failure was estimated and found to be significantly decreased when compared to healthy subjects. There was a negative correlation between the decrease of the erythrocyte protoporphyrin and the blood urea and haematocrit. Following haemodialysis the concentration of erythrocyte protoporphyrin was reduced but not significantly so. It is proposed that uraemia or insufficiency of erythropoietin could affect erythroblasts and young red cells impairing haem synthesis.
Introduction
Anaemia is a constant finding in chronic renal failure; however, its pathogenesis is obscure in many respects and this is particularly so with regard to the reduced survival time of the red blood cells. A possible cause for this is a disturbance of the normal metabolism of erythrocytes. There is a paucity of information in the literature with respect to the metabolism of erythrocyte porphyrin [l] and particularly of protoporphyrin, in patients suffering from chronic renal failure. In the present study the results of erythrocyte protoporphyrin determinations in 63 patients suffering from chronic renal failure are reported and our findings on the relationships between erythrocyte protoporphyrin on one hand and the severity of uraemia and the value of the haematocrit on the other are presented.
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r :- 0.426 p < 0,001 N =
80
0
I
63
. .
.
.
.
100
200
Blood Fig. 1. Correlation
TABLE
between
300
400
urea
500
mg/lOOml
erythrocyte
protoporphyrin
(Y)
and blood
urea (x):
N = 200x
+ 42.555.
I
ERYTHROCYTE
PROTOPORPHYRIN
Erythrocyte protoporphyrin We/ 100 ml erythro-
IN URAEMIC
PATIENTS
AND NORMAL
CONTROLS
Mean f S.D. (range)
cyte)
Normal Controls (iv = 55)
Uraemic Patients (N = 63)
59 f 12.8 (32-l 10)
43 f 15.8 (24-95)
Significance*
Haemodialysis before
P < 0.001
38 f 15.7 (23-95)
(N = 18)
Significance*
after 35 * 7.8 (28-60)
N.S.
* t-test
r : -0.374 P < 0.01 N = 63
w A_
10 20
30 40
Haematocrlt Fig. 2. Correlation
between
50
60
70
910
erythrocyte
protoporphyrin
(Y)
and haematocrit
(x): y = 30x + 41.8.
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Material and Methods One hundred and thirty six adults, of both sexes, aged 18 to 68 years were studied. They were divided into three groups. Group I. Sixty-three uraemic patients suffering from chronic renal failure of variable aetiology, with blood urea values constantly exceeding 100 mg% (range loo-422 mg%). No patient had undergone peritoneal dialysis or haemodialysis. Group II. Fifty-five normal adults used as controls. Group III. Eighteen uraemic patients in whom erythrocyte protoporphyrin was estimated before and after haemodialysis. 5 ml of whole blood was placed in a sterile dry oxalated test tube for the haematocrit and 5 ml in another test tube containing 0.1 ml of 1% aqueous solution of sodium heparin (1000 I.U. per ml) for blood urea and erythrocyte protoporphyrin determinations. Red cell protoporphyrin was estimated by the method of Heller et al. [2] and blood urea by the urease Nessler method of King and Wootton [ 31. Results In this investigation a decrease in erythrocyte protoporphyrin concentration was found in uraemic patients when compared to normal control subjects. (Table I). ‘This decrease was statistically highly significant (P < 0.001). A negative correlation between the decrease in protoporphyrin and blood urea (P < 0.001, r = -0.426, Fig. 1) or haematocrit (P < 0.01; r = -0.374, Fig. 2) was found. Following haemodialysis a decrease in erythrocyte protoporphyrin, but not statistically significant was noted (Table I). Discussion In man, haem is synthesised mainly in the erythroblasts of the bone marrow [4], but can also be produced by circulating reticulocytes. This process appears to be linked within the mitochondria, where oxidative reactions are known to occur whereas decarboxylating reactions occur in the endoplasmic reticulum. The data presented showed a significant reduction of erythrocyte protoporphyrin both in undialysed and dialysed patients with chronic uraemia in comparison to normal controls. A satisfactory explanation for this abnormality cannot be offered on the evidence available. It is possible that uraemia or erythropoietin deficiency could influence effectively porphyrin metabolism. If this is the case, then chronic renal failure could affect the mitochondria of the erythroblasts and the enzyme systems responsible for haem synthesis [5], particularly after the synthesis of aminolaevulinic acid [6] and porphobilinogen 173 and thus cause a reduction of protoporphyrin production. In contrast, Loge et al. [ 81 in their effort to characterize the anaemia associated with chronic renal failure, found significantly elevated values of free
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erythrocyte protoporphyrin in eight of the twenty-one patients. These results could not be correlated with the type of renal disease, degree of azotemia, severity of anaemia, or with the presence or absence of a haemolytic component. Cartwright et al. [9] in their study also found elevated erythrocyte protoporphyrin values in six of seven patients with anaemia and azotaemia. Wintrobe [lo] has reported in the anaemia of iron deficiency, heavy metal intoxication, chronic infection, leukaemia, Hodgkin’s disease and multiple myeloma as well as in the haemolytic and refractory anaemias, elevated values of free erythrocyte protoporphyrin. References 1 wrane, L. (1960). Acta Paediat. (Stockholm), 49, SUPPI. 124, 1 2 Heller, S.R., Labbe, R.F. and Nutter, J. (1971) Clin. Chem. 17. 525 3 King. E.J. and Wootton, I.D.P. (1956) in Microanalysis in Medical Biochemistry, PP. 14-16. Churchill, London 4 Rimington, C. and Cripps, D.J. (1965). Lancet. i. 624 5 Granick, S. and Mauzerall, D. (1958). Ann. N. Y. Acad. Sci. 75. 115 6 Zazgomik, J., Pils, P. and Schmidt, P.: S-Aminolevulinic acid in patients on regular dialysis treatment, 1st Balkan Meeting on renal disease. 11-13th May 1973, Thessaloniki, Greece 7 Leber, H.W. and Schiitterle, G.: New aspects concerning uremic anemia. XI Congress of the European dialysis and transplant association, 3-8 November 1974, Tel Aviv. Israel 8 Loge, J.P., Lange, R.D. and Moore, C.V. (1950). J. CIin. Investigation, 29, 830 9 Cartwright. G.E., Huguley. C.M., Jr., Ashenbrucker. H.. Fay, J. and Wintrobe, M.M. (1948). Blood, 3. 501 10 Wintrobe, M.M. (1961) in Clinical Hematology. Philadelphia, Lea and Febiger