Effects of S-nitrosation on hemoglobin-induced microvascular damage.
Blood substitutes, such as diaspirin cross-linked hemoglobin (Hb), cause microvascular leakiness to macromolecules. Because of the potentially stabilizing effects of nitric acid (NO) on endothelium, experiments were performed to determine whether S-nitrosohemoglobin (SNO-Hb), a potential NO-donor Hb-based blood substitute, would not cause microvascular damage. Release of NO, or its metabolites, from the SNO-Hb was facilitated by addition of glutathione, which aids in the decomposition of S-nitrosothiols. In anesthetized rats, the mesenteric microvasculature was perfused with SNO-Hb with glutathione (six rats), SNO-Hb alone (six rats), or saline (eight rats) for 10 min, followed by fluorescein isothiocyanate (FITC)-albumin for 1 min, and finally fixed for epifluorescence microscopic examination. When comparing the SNO-Hb group with saline, both the numbers and areas of leaks were significantly increased [0.019 +/- 0.003 (SEM) microm vs. 0.0030 +/- 0.0004 and 7.36 +/- 1.50 vs. 0.156 +/- 0.035 (p < 0.005)]. With the addition of glutathione, leakage was still high (0.005 +/- 0.00005 microm and 5.086 +/- 0.064 microm) but decreased compared with SNO-Hb alone (p < 0.005). In conclusion, NO, or a related vasodilator, when released from SNO-Hb, significantly reduces but does not eliminate microvascular damage. Further improvements may result by S-nitrosating a more stable form of modified hemoglobin.
Burke
Tara K
TK
Program of Biomedical Engineering, University of Arizona, Tucson, 85724, USA.
Teng
Xinjun
X
Patel
Rakesh P
RP
Baldwin
Ann L
AL
D000818:Animals; D001241:Aspirin / Q000031:analogs & derivatives* / Q000494:pharmacology; D001802:Blood Substitutes / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D005978:Glutathione / Q000378:metabolism / Q000494:pharmacology; D006454:Hemoglobins / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D008833:Microcirculation / Q000187:drug effects; D008856:Microscopy, Fluorescence; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology; D015538:Nitrosation; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D013152:Splanchnic Circulation / Q000187:drug effects; D014665:Vasodilator Agents / Q000378:metabolism / Q000494:pharmacology; D014699:Venules / Q000187:drug effects / Q000378:metabolism
D001802:Blood Substitutes; D005456:Fluorescent Dyes; D006454:Hemoglobins; D009566:Nitrates; D014665:Vasodilator Agents; D009569:Nitric Oxide; C083478:diaspirin-cross-linked hemoglobin; D005978:Glutathione; D016650:Fluorescein-5-isothiocyanate; D001241:Aspirin