Hemodynamic and renal effects of cross-linked hemoglobin
infusion.
Cases, Aleix, John M. Stulak, Zvonimir Katusic, Eduardo Villa, J. C.
Romero.
Department of Physiology and Biophysics and Department of
Anesthesiology, Mayo School of Medicine and Mayo Clinic
APStracts 3:0338R, 1996.
It is well known that hemoglobin binds nitric oxide producing a
pronounced vasoconstriction in isolated arteries. However, it is
debatable whether or not such an effect takes place in whole animals,
because hemoglobin is also known to catalyze the formation of
prostaglandins from arachidonic acid. Acute studies were performed to
evaluate the effects induced by intravenous infusion of cross-linked
hemoglobin (XL-Hb) on blood pressure and renal, iliac, and mesenteric
flows, as well as on renal function in 6 anesthetized dogs. A similar
volume-matched expansion with 6% Dextran was used as control (n=6).
Glomerular filtration rate (GFR), urinary flow, and total and
fractional sodium excretion were measured before and after XL-Hb or
dextran infusion to evaluate possible renal function changes. XL-Hb
administration resulted in a 29 % elevation in BP and a significant
decrease of blood flow (30-37%) to the three vascular beds. XL-Hb did
not alter GFR or sodium excretion, despite the increase in BP. In
contrast, the administration of Dextran did not significantly alter
BP but induced a significant increase (6-13%) of blood flow in the
three vascular beds. These changes were accompanied by three-fold
increases in urinary flow and sodium excretion without alterations in
GFR. The binding effect of XL-Hb on NO was studied in isolated renal
arteries in organ chambers. These in vitro studies demonstrated that
XL-Hb blunted the endothelium-mediated vasodilator response to
calcium ionophore A23187 and to acetylcholine. Our results
demonstrate that XL-Hb administration is followed by hypertension,
vasoconstriction and blunted natriuresis. All these effects are
compatible with the scavenging effect on NO attributed to XL-Hb.
Received 29 April 1996; accepted in final form 5 August 1996.
APS Manuscript Number R240-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996