Format

Send to

Choose Destination
Am J Pathol. 2008 Jul;173(1):289-99. doi: 10.2353/ajpath.2008.071130. Epub 2008 Jun 13.

Hemopexin prevents endothelial damage and liver congestion in a mouse model of heme overload.

Author information

1
Molecular Biotechnology Center, Via Nizza 52, 10126 Torino, Italy. emanuela.tolosano@unito.it.

Abstract

Intravascular hemolysis results in the release of massive amounts of hemoglobin and heme into plasma, where they are rapidly bound by haptoglobin and hemopexin, respectively. Data from haptoglobin and hemopexin knockout mice have shown that both proteins protect from renal damage after phenylhydrazine-induced hemolysis, whereas double-mutant mice were especially prone to liver damage. However, the specific role of hemopexin remains elusive because of the difficulty in discriminating between hemoglobin and heme recovery. To study the specific role of hemopexin in intravascular hemolysis, we established a mouse model of heme overload. Under these conditions, both endothelial activation and vascular permeability were significantly higher in hemopexin-null mice compared with wild-type controls. Vascular permeability was particularly altered in the liver, where congestion in the centrolobular area was believed to be associated with oxidative stress and inflammation. Liver damage in hemopexin- null mice may be prevented by induction of heme oxygenase-1 before heme overload. Furthermore, heme-treated hemopexin-null mice exhibited hyperbilirubinemia, prolonged heme oxygenase-1 expression, excessive heme metabolism, and lack of H-ferritin induction in the liver compared with heme-treated wild-type controls. Moreover, these mutant mice metabolize an excess of heme in the kidney. These studies highlight the importance of hemopexin in heme detoxification, thus suggesting that drugs mimicking hemopexin activity might be useful to prevent endothelial damage in patients suffering from hemolytic disorders.

PMID:
18556779
PMCID:
PMC2438305
DOI:
10.2353/ajpath.2008.071130
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center