Kinetic study of adenosine concentrations and the expression of adenosine deaminase in mononuclear cells during hemodialysis.
BACKGROUND
We previously showed that high intralymphocytic adenosine (Ado) concentrations are found in hemodialyzed patients due to the reduced activity of mononuclear cell adenosine deaminase (MCADA). These abnormalities contribute to the immune defect observed in HD patients. The kinetics of these abnormalities and the causes of the low MCADA activity, however, have not been investigated. Here, we addressed this question. Since interferon gamma (IFNgamma) partially modulates MCADA, we also evaluated the effect of IFNgamma on MCADA activity in vitro.


RESULTS
The study included 12 patients (eight men and four women) who were observed from the first to the 36th hemodialysis (HD) session, and eight healthy subjects (controls). MCADA activity and Ado concentrations were normal before the first HD session. Ado concentrations progressively increased from the first (10.5 +/- 3.1 pmol/10(7) cells) to the fourth session (26.7 +/- 3 pmol/10(7) cells), before stabilizing at a high level. MCADA activity increased transiently until the second session (2.2 +/- 0.5 IU/10(7) cells before HD vs. 2.8 +/- 0.6 IU/10(7)cells), and then decreased and stabilized at a low level (1.0 +/- 0.5 IU/10(7)cells). The amount of MCADA mRNA transiently increased until the third session (mRNA MCADA/mRNA beta-actin: 0.6 +/- 0.2 vs. 0.8 +/- 0.2), and then decreased to 0.3 +/- 0.1 at the 36th session. MCADA activity underwent a dose-dependent increase after IFNgamma stimulation.


CONCLUSIONS
HD affects the transcription of the gene encoding MCADA after just three HD sessions, leading to decreased MCADA activity and increased plasma concentration of Ado.
Service de Néphrologie et d'Hémodialyse, Hôpital de la Conception, Marseille, France.
Bertrand
B
Dussol
Emmanuel
E
Fenouillet
Phillippe
P
Brunet
Radj
R
Purgus
Nicole
N
Sauze
Louis
L
Carrega
Laurence
L
Mercier
Ibrahim
I
Zouher
Guy
G
Bechis
Yvon
Y
Berland
Regis
R
Guieu
D000241:Adenosine / Q000378:metabolism*; D000243:Adenosine Deaminase / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000494:pharmacology; D007676:Kidney Failure, Chronic / Q000276:immunology / Q000378:metabolism* / Q000628:therapy; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D006435:Renal Dialysis
D007155:Immunologic Factors; D016898:Interferon-alpha; D012333:RNA, Messenger; D000243:Adenosine Deaminase; D000241:Adenosine