Model of nitric oxide diffusion in an arteriole: impact of hemoglobin-based blood substitutes

2002 ◽  
Vol 282 (6) ◽  
pp. H2245-H2253 ◽  
Author(s):  
Mahendra Kavdia ◽  
Nikolaos M. Tsoukias ◽  
Aleksander S. Popel

Administration of hemoglobin-based oxygen carriers (HBOCs) frequently results in vasoconstriction that is primarily attributed to the scavenging of endothelium-derived nitric oxide (NO) by cell-free hemoglobin. The ensuing pressor response could be caused by the high NO reactivity of HBOC in the vascular lumen and/or the extravasation of hemoglobin molecules. There is a need for quantitative understanding of the NO interaction with HBOC in the blood vessels. We developed a detailed mathematical model of NO diffusion and reaction in the presence of an HBOC for an arteriolar-size vessel. The HBOC reactivity with NO and degree of extravasation was studied in the range of 2–58 × 106 M−1 · s−1 and 0–100%, respectively. The model predictions showed that the addition of HBOC reduced the smooth muscle (SM) NO concentration in the activation range (12–28 nM) for soluble guanylate cyclase, a major determinant of SM contraction. The SM NO concentration was significantly reduced when the extravasation of HBOC molecules was considered. The myoglobin present in the parenchymal cells scavenges NO, which reduces the SM NO concentration.

2017 ◽  
Vol 122 (5) ◽  
pp. 1227-1237 ◽  
Author(s):  
Yannick J. Taverne ◽  
Daphne de Wijs-Meijler ◽  
Maaike te Lintel Hekkert ◽  
Paula F. Moon-Massat ◽  
Gregory P. Dubé ◽  
...  

Hemoglobin-based oxygen carrier (HBOC)-201 is a cell-free modified hemoglobin solution potentially facilitating oxygen uptake and delivery in cardiovascular disorders and hemorrhagic shock. Clinical use has been hampered by vasoconstriction in the systemic and pulmonary beds. Therefore, we aimed to 1) determine the possibility of counteracting HBOC-201-induced pressor effects with either adenosine (ADO) or nitroglycerin (NTG); 2) assess the potential roles of nitric oxide (NO) scavenging, reactive oxygen species (ROS), and endothelin (ET) in mediating the observed vasoconstriction; and 3) compare these effects in resting and exercising swine. Chronically instrumented swine were studied at rest and during exercise after administration of HBOC-201 alone or in combination with ADO. The role of NO was assessed by supplementation with NTG or administration of the eNOS inhibitor Nω-nitro-l-arginine. Alternative vasoactive pathways were investigated via intravenous administration of the ETA/ETB receptor blocker tezosentan or a mixture of ROS scavengers. The systemic and to a lesser extent the pulmonary pressor effects of HBOC-201 could be counteracted by ADO; however, dosage titration was very important to avoid systemic hypotension. Similarly, supplementation of NO with NTG negated the pressor effects but also required titration of the dose. The pressor response to HBOC-201 was reduced after eNOS inhibition and abolished by simultaneous ETA/ETB receptor blockade, while ROS scavenging had no effect. In conclusion, the pressor response to HBOC-201 is mediated by vasoconstriction due to NO scavenging and production of ET. Further research should explore the effect of longer-acting ET receptor blockers to counteract the side effect of hemoglobin-based oxygen carriers. NEW & NOTEWORTHY Hemoglobin-based oxygen carrier (HBOC)-201 can disrupt hemodynamic homeostasis, mimicking some aspects of endothelial dysfunction, resulting in elevated systemic and pulmonary blood pressures. HBOC-201-induced vasoconstriction is mediated by scavenging nitric oxide (NO) and by upregulating endothelin (ET) production. Pressor effects can be prevented by adjuvant treatment with NO donors or direct vasodilators, such as nitroglycerin or adenosine, but dosages must be carefully monitored to avoid hypotension. However, hemodynamic normalization is more easily achieved via administration of an ET receptor blocker.


2008 ◽  
Vol 44 ◽  
pp. 63-84 ◽  
Author(s):  
Chris E. Cooper

Optimum performance in aerobic sports performance requires an efficient delivery to, and consumption of, oxygen by the exercising muscle. It is probable that maximal oxygen uptake in the athlete is multifactorial, being shared between cardiac output, blood oxygen content, muscle blood flow, oxygen diffusion from the blood to the cell and mitochondrial content. Of these, raising the blood oxygen content by raising the haematocrit is the simplest acute method to increase oxygen delivery and improve sport performance. Legal means of raising haematocrit include altitude training and hypoxic tents. Illegal means include blood doping and the administration of EPO (erythropoietin). The ability to make EPO by genetic means has resulted in an increase in its availability and use, although it is probable that recent testing methods may have had some impact. Less widely used illegal methods include the use of artificial blood oxygen carriers (the so-called ‘blood substitutes’). In principle these molecules could enhance aerobic sports performance; however, they would be readily detectable in urine and blood tests. An alternative to increasing the blood oxygen content is to increase the amount of oxygen that haemoglobin can deliver. It is possible to do this by using compounds that right-shift the haemoglobin dissociation curve (e.g. RSR13). There is a compromise between improving oxygen delivery at the muscle and losing oxygen uptake at the lung and it is unclear whether these reagents would enhance the performance of elite athletes. However, given the proven success of blood doping and EPO, attempts to manipulate these pathways are likely to lead to an ongoing battle between the athlete and the drug testers.


2007 ◽  
Vol 292 (2) ◽  
pp. H893-H903 ◽  
Author(s):  
Galina N. Antonova ◽  
Connie M. Snead ◽  
Alexander S. Antonov ◽  
Christiana Dimitropoulou ◽  
Richard C. Venema ◽  
...  

Large (pathological) amounts of nitric oxide (NO) induce cell injury, whereas low (physiological) NO concentrations often ameliorate cell injury. We tested the hypotheses that pretreatment of endothelial cells with low concentrations of NO (preconditioning) would prevent injury induced by high NO concentrations. Apoptosis, induced in bovine aortic endothelial cells (BAECs) by exposing them to either 4 mM sodium nitroprusside (SNP) or 0.5 mM N-(2-aminoethyl)- N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine (spermine NONOate) for 8 h, was abolished by 24-h pretreatment with either 100 μM SNP, 10 μM spermine NONOate, or 100 μM 8-bromo-cGMP (8-Br-cGMP). Repair of BAECs following wounding, measured as the recovery rate of transendothelial electrical resistance, was delayed by 8-h exposure to 4 mM SNP, and this delay was significantly attenuated by 24-h pretreatment with 100 μM SNP. NO preconditioning produced increased association and expression of soluble guanyl cyclase (sGC) and heat shock protein 90 (HSP90). The protective effect of NO preconditioning, but not the injurious effect of 4 mM SNP, was abolished by either a sGC activity inhibitor 1H-[1,2,4]oxadiazolo-[4,3- a]quinoxalin-1-one (ODQ) or a HSP90 binding inhibitor (radicicol) and was mimicked by 8-Br-cGMP. We conclude that preconditioning with a low dose of NO donor accelerates repair and maintains endothelial integrity via a mechanism that includes the HSP90/sGC pathway. HSP90/sGC may thus play a role in the protective effects of NO-generating drugs from injurious stimuli.


2010 ◽  
Vol 28 (8) ◽  
pp. 1666-1675 ◽  
Author(s):  
Yuliya Sharkovska ◽  
Philipp Kalk ◽  
Bettina Lawrenz ◽  
Michael Godes ◽  
Linda Sarah Hoffmann ◽  
...  

2011 ◽  
Vol 89 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Ercan Ozdemir ◽  
Ihsan Bagcivan ◽  
Nedim Durmus ◽  
Ahmet Altun ◽  
Sinan Gursoy

Although the phenomenon of opioid tolerance has been widely investigated, neither opioid nor nonopioid mechanisms are completely understood. The aim of the present study was to investigate the role of the nitric oxide (NO)–cyclic guanosine monophosphate (cGMP) pathway in the development of morphine-induced analgesia tolerance. The study was carried out on male Wistar albino rats (weighing 180–210 g; n = 126). To develop morphine tolerance, animals were given morphine (50 mg/kg; s.c.) once daily for 3 days. After the last dose of morphine was injected on day 4, morphine tolerance was evaluated. The analgesic effects of 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1), BAY 41-2272, S-nitroso-N-acetylpenicillamine (SNAP), NG-nitro-l-arginine methyl ester (L-NAME), and morphine were considered at 15 or 30 min intervals (0, 15, 30, 60, 90, and 120 min) by tail-flick and hot-plate analgesia tests (n = 6 in each study group). The results showed that YC-1 and BAY 41-2272, a NO-independent activator of soluble guanylate cyclase (sGC), significantly increased the development and expression of morphine tolerance, and L-NAME, a NO synthase (NOS) inhibitor, significantly decreased the development of morphine tolerance. In conclusion, these data demonstrate that the nitric oxide–cGMP signal pathway plays a pivotal role in developing tolerance to the analgesic effect of morphine.


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