Nitric oxide synthetic capacity in relation to dialysate temperature.
BACKGROUND
During hemodialysis, vascular reactivity is impaired, which can be corrected by lowering dialysate temperature. It has also been shown that nitric oxide (NO) is related to intradialytic hypotension. As NO synthesis may be temperature-dependent, this study addressed the influence of dialysate temperature on the NO synthetic capacity of plasma.


METHODS
NO synthetic capacity was studied during hemodialysis with a dialysate temperature of 37.5 degrees C (dialysis-37.5 degrees C) and programmed extracorporeal blood cooling (cool dialysis; Blood Temperature Monitor; Fresenius C) in 12 stable patients. NO synthetic capacity was assessed ex vivo by [3H]L-citrulline formation from [3H]L-arginine in cultured endothelial cells after incubation with plasma samples obtained during the respective sessions.


RESULTS
Core temperature decreased (-0.32 +/- 0.10 degrees C) and energy transfer rate was significantly lower (-27.5 +/- 2.8 W; p < 0.05) during cool dialysis compared to dialysis-37.5 degrees C (0.19 +/- 0.06 degrees C and -0.8 +/- 1.2 W respectively; p < 0.05). Systolic blood pressure decreased during dialysis-37.5 degrees C (-19 +/- 4 mm Hg; p < 0.05), but not during cool dialysis (-6 +/- 5 mm Hg). NO synthetic capacity increased during dialysis-37.5 degrees C (55.5 +/- 9.3 to 73.5 +/- 10.2 pmol/10(5) cells; p < 0.05), in contrast to cool dialysis (67.3 +/- 11.1 to 66.2 +/- 10.8 pmol/10(5) cells).


CONCLUSIONS
The stimulatory effect of uremic plasma on endothelial NO synthesis was augmented during dialysis-37.5 degrees C but not during cool dialysis.
Beerenhout
Charles H
CH
Department of Internal Medicine, University Hospital Maastricht, Maastricht, The Netherlands.
Noris
Marina
M
Kooman
Jeroen P
JP
Porrati
Francesca
F
Binda
Elena
E
Morigi
Marina
M
Bekers
Otto
O
van der Sande
Frank M
FM
Todeschini
Marta
M
Macconi
Daniela
D
Leunissen
Karel M L
KM
Remuzzi
Giuseppe
G
D000368:Aged; D001120:Arginine / Q000032:analysis / Q000378:metabolism; D004730:Endothelium, Vascular / Q000201:enzymology; D004735:Energy Transfer; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007674:Kidney Diseases / Q000201:enzymology / Q000378:metabolism / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D006435:Renal Dialysis / Q000009:adverse effects*; D013696:Temperature
D009569:Nitric Oxide; D001120:Arginine; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III