Hemopexin therapy improves cardiovascular function by preventing heme-induced endothelial toxicity in mouse models of hemolytic diseases

Circulation. 2013 Mar 26;127(12):1317-29. doi: 10.1161/CIRCULATIONAHA.112.130179. Epub 2013 Feb 27.

Abstract

Background: Hemolytic diseases are characterized by enhanced intravascular hemolysis resulting in heme-catalyzed reactive oxygen species generation, which leads to endothelial dysfunction and oxidative damage. Hemopexin (Hx) is a plasma heme scavenger able to prevent endothelial damage and tissue congestion in a model of heme overload. Here, we tested whether Hx could be used as a therapeutic tool to counteract heme toxic effects on the cardiovascular system in hemolytic diseases.

Methods and results: By using a model of heme overload in Hx-null mice, we demonstrated that heme excess in plasma, if not bound to Hx, promoted the production of reactive oxygen species and the induction of adhesion molecules and caused the reduction of nitric oxide availability. Then, we used β-thalassemia and sickle cell disease mice as models of hemolytic diseases to evaluate the efficacy of an Hx-based therapy in the treatment of vascular dysfunction related to heme overload. Our data demonstrated that Hx prevented heme-iron loading in the cardiovascular system, thus limiting the production of reactive oxygen species, the induction of adhesion molecules, and the oxidative inactivation of nitric oxide synthase/nitric oxide, and promoted heme recovery and detoxification by the liver mainly through the induction of heme oxygenase activity. Moreover, we showed that in sickle cell disease mice, endothelial activation and oxidation were associated with increased blood pressure and altered cardiac function, and the administration of exogenous Hx was found to almost completely normalize these parameters.

Conclusions: Hemopexin treatment is a promising novel therapy to protect against heme-induced cardiovascular dysfunction in hemolytic disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Sickle Cell / drug therapy*
  • Anemia, Sickle Cell / metabolism
  • Anemia, Sickle Cell / physiopathology
  • Animals
  • Cardiovascular System / drug effects
  • Cardiovascular System / physiopathology*
  • Disease Models, Animal
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiopathology*
  • Heme / adverse effects*
  • Heme / metabolism
  • Hemopexin / genetics
  • Hemopexin / pharmacology
  • Hemopexin / therapeutic use*
  • Mice
  • Mice, Knockout
  • Mice, SCID
  • Nitric Oxide / metabolism
  • Reactive Oxygen Species / metabolism
  • Treatment Outcome
  • beta-Thalassemia / drug therapy*
  • beta-Thalassemia / metabolism
  • beta-Thalassemia / physiopathology

Substances

  • Reactive Oxygen Species
  • Nitric Oxide
  • Heme
  • Hemopexin