title: Annexin V detection of lipopolysaccharide-induced cardiac apoptosis.
abstract: Acute inflammatory response to lipopolysaccharide (LPS) exposure is typically associated with cardiac myocyte apoptosis, which is difficult to quantify because of heart tissue specificity. We report here that radioiodinated Annexin V (I-AnxV), a specific ligand of phosphatidylserine exposed by apoptotic cells, allows tissue detection of apoptosis in LPS-treated rat hearts. Heart I-AnxV uptake was significantly increased in all cardiac territories of LPS-treated rats. In contrast, I-human serum albumin myocardial uptake was only slightly increased in LPS-treated rat hearts, suggesting limited changes in vascular protein permeability. Autoradiography of endotoxin-treated rat heart sections with I-AnxV in association with deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling and caspase 3 staining allows identification of double positive cardiac myocytes. Inhibition of apoptosis by caspase inhibitors (i.e., ZVAD.fmk and DEVD.cmk) reduced I-AnxV myocardial uptake in LPS-treated rats. Eventually, endotoxin-treated rats displayed pathological uptake of Tc-annexin in the cardiac mediastinal region whereas zVAD.fmk reduced Tc-annexin mediastinal uptake. Our results show that radioactive I-AnxV signal emerging from LPS-treated rat hearts could be related to the activation of caspase-dependent apoptotic pathway in cardiac myocytes.
authors.affiliation: INSERM Unité 814, Faculty of Medicine, Place de Verdun, Lille, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Pétillot
authors.forename: Christophe
authors.initials: C
authors.lastname: Lahorte
authors.forename: Elena
authors.initials: E
authors.lastname: Bonanno
authors.forename: Alberto
authors.initials: A
authors.lastname: Signore
authors.forename: Steve
authors.initials: S
authors.lastname: Lancel
authors.forename: Philippe
authors.initials: P
authors.lastname: Marchetti
authors.forename: Benoit
authors.initials: B
authors.lastname: Vallet
authors.forename: Guido
authors.initials: G
authors.lastname: Slegers
authors.forename: Rémi
authors.initials: R
authors.lastname: Neviere
mesh_terms: D000818:Animals; D017304:Annexin A5; D017209:Apoptosis / Q000502:physiology*; D004195:Disease Models, Animal; D007457:Iodine Radioisotopes; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D009206:Myocardium / Q000276:immunology / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000175:diagnosis
chemical_list: D017304:Annexin A5; D007457:Iodine Radioisotopes; D008070:Lipopolysaccharides