RESUMEN
Hemoglobin-based oxygen carriers (HBOCs) may generate oxidative stress, vasoconstriction and inflammation. To reduce these undesirable vasoactive properties, we increased hemoglobin (Hb) molecular size by genetic engineering with octameric Hb, recombinant (r) HbßG83C. We investigate the potential side effects of rHbßG83C on endothelial cells. The rHbßG83C has no impact on cell viability, and induces a huge repression of endothelial nitric oxide synthase gene transcription, a marker of vasomotion. No induction of Intermolecular-Adhesion Molecule 1 and E-selectin (inflammatory markers) transcription was seen. In the presence of rHbßG83C, the transcription of heme oxygenase-1 (oxidative stress marker) is weakly increased compared to the two other HBOCs (references) or Voluven (control). This genetically engineered octameric Hb, based on a human Hb ßG83C mutant, leads to little impact at the level of endothelial cell inflammatory response and thus appears as an interesting molecule for HBOC development.
Asunto(s)
Sustitutos Sanguíneos/farmacología , Hemoglobinas/farmacología , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Biomarcadores , Sustitutos Sanguíneos/toxicidad , Supervivencia Celular/efectos de los fármacos , Dextranos/farmacología , Dextranos/toxicidad , Regulación hacia Abajo/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Selectina E/biosíntesis , Selectina E/genética , Regulación de la Expresión Génica/efectos de los fármacos , Hemo-Oxigenasa 1/biosíntesis , Hemo-Oxigenasa 1/genética , Hemoglobinas/análisis , Hemoglobinas/química , Hemoglobinas/toxicidad , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Derivados de Hidroxietil Almidón/farmacología , Derivados de Hidroxietil Almidón/toxicidad , Inflamación/inducido químicamente , Molécula 1 de Adhesión Intercelular/biosíntesis , Molécula 1 de Adhesión Intercelular/genética , Metahemoglobina/análisis , Modelos Moleculares , Óxido Nítrico Sintasa de Tipo III/biosíntesis , Óxido Nítrico Sintasa de Tipo III/genética , Estrés Oxidativo/efectos de los fármacos , Sustitutos del Plasma/farmacología , Sustitutos del Plasma/toxicidad , Conformación Proteica , Reacción en Cadena en Tiempo Real de la Polimerasa , Vasoconstricción/efectos de los fármacosRESUMEN
PURPOSE: The iron chelating agent deferoxamine mesylate USP (Desferal, Ciba, Summit, NJ) is commonly used in the treatment of acute iron intoxication and chronic iron overload (associated with the transfusion-dependent anemias). When used for prolonged periods of time or in high doses deferoxamine is attended by a range of ocular toxicities. The visual symptoms associated with deferoxamine administration often limit effective iron chelation therapy and can result in permanent vision loss. Deferoxamine has recently been conjugated to certain high molecular weight biocompatible polymers without altering its iron-binding properties. Here the effect of conjugation of deferoxamine to hydroxyethyl starch on retinal toxicity is examined. METHODS: An albino rat model of electroretinographically determined, deferoxamine-induced retinal toxicity has been previously described. We use this model to evaluate and compare both native deferoxamine and hydroxyethyl starch conjugated deferoxamine. RESULTS: Our data show that retinal function, as assessed by the electroretinogram b-wave, is significantly depressed 1 day after a single dose of native deferoxamine, while the b-waves of rats receiving a single dose of hydroxyethyl starch-deferoxamine, are not significantly depressed at any time during the study. In addition, the administered dose of hydroxyethyl starch-deferoxamine resulted in plasma deferoxamine concentrations up to five times greater than those achieved with native deferoxamine. CONCLUSION: These results suggest that hydroxyethyl starch conjugated deferoxamine is associated with less retinal toxicity than native deferoxamine and that it may be a safer alternative for iron chelation therapy.