title: The presence of apoptotic bone marrow cells impairs the efficacy of cardiac cell therapy.
abstract: Injection of autologous bone marrow cells into infarcted myocardium has been proposed to limit the deterioration of cardiac function following myocardial infarction (MI); unfortunately, the beneficial effects observed have been modest. One of the limiting factors is believed to be poor  local survival of the injected cells, but the potential impact of apoptosis among the injected cells has yet to be assessed. Therefore, this study aimed to quantify the apoptosis rate in bone marrow mononuclear cells (BMMCs) prepared for cardiac therapy, and to analyze their effects in vitro  on cardiomyoblast apoptosis and in vivo on cardiac function recovery following MI. Using rabbit BMMCs prepared by Ficoll gradient, apoptotic cells were detected via Annexin V (AnV) staining. The effects of depleting the apoptotic cell population by means of AnV magnetic beads was tested in  vitro after coculture with cardiomyoblasts (H9c2 cells) and in vivo after cell injection into the infarcted area. Left ventricular ejection fraction and scar extent were assessed by echography and histology 2 months later. After Ficoll gradient isolation, 37.3% (33.4-37.9%) of BMMCs  were found to be apoptotic (Apo(Base) BMMCs). AnV depletion decreased the proportion of apoptotic cells to 20% (17.6-32%) (Apo(Low) BMMCs). Rabbits treated in vivo with Apo(Low) BMMCs after MI presented with significantly improved left ventricular ejection  fraction [41.4% (41.0-43.6%) vs. 34.6% (34.6-35.9%), p = 0.03), reduced scar extent [20.4% (17.9-24.3%) vs. 25.6% (17.9-27.9%), p = 0.057], and reduced rate of cardiomyocyte apoptosis compared to those treated with Apo(Base) BMMCs. H9c2 apoptosis  was found to be higher after coculture with Apo(Base) than with Apo(Low) BMMCs [25.6% (22.6-29.6%) vs. 10.1% (6.6-12.6%), p = 0.03], a result partially reproduced by cocultures with microparticle-rich supernatants from BMMCs. The presence of apoptotic  cells among BMMCs impairs the efficacy of cardiac cell therapy after MI, an effect possibly mediated by apoptotic microparticles.
authors.affiliation: Université Lille Nord de France, EA 2693, Lille, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Mouquet
authors.forename: Gilles
authors.initials: G
authors.lastname: Lemesle
authors.forename: Cedric
authors.initials: C
authors.lastname: Delhaye
authors.forename: Clement
authors.initials: C
authors.lastname: Charbonnel
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ung
authors.forename: Delphine
authors.initials: D
authors.lastname: Corseaux
authors.forename: Olivier
authors.initials: O
authors.lastname: Fabre
authors.forename: Francis
authors.initials: F
authors.lastname: Juthier
authors.forename: Philippe
authors.initials: P
authors.lastname: Marchetti
authors.forename: Remi
authors.initials: R
authors.lastname: Neviere
authors.forename: Eric
authors.initials: E
authors.lastname: Van Belle
authors.forename: Brigitte
authors.initials: B
authors.lastname: Jude
authors.forename: Sophie
authors.initials: S
authors.lastname: Susen
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000737:chemistry / Q000378:metabolism; D017209:Apoptosis; D001854:Bone Marrow Cells / Q000166:cytology*; D016026:Bone Marrow Transplantation; D002460:Cell Line; D002469:Cell Separation; D064987:Cell- and Tissue-Based Therapy; D018920:Coculture Techniques; D005362:Ficoll / Q000737:chemistry; D006352:Heart Ventricles / Q000503:physiopathology; D009203:Myocardial Infarction / Q000473:pathology / Q000628:therapy*; D032383:Myocytes, Cardiac / Q000166:cytology; D011817:Rabbits; D020257:Ventricular Remodeling
chemical_list: D017304:Annexin A5; D005362:Ficoll