title: Removing the cells from adult bone marrow derived stem cell therapy does not eliminate cardioprotection.
abstract: OBJECTIVE
  The debate as to whether adult stem cell therapy is regenerative or not continues. The non-regenerative benefits of adult bone marrow-derived stem cell therapy were investigated by testing whether the supernatant derived from unfractionated bone marrow mononuclear cells might be cardioprotective in an animal model of myocardial ischaemia-reperfusion injury.
  
  
  METHODS
  Regional myocardial reperfusion injury was acquired by 25 min reversible left anterior descending coronary artery (LAD) occlusion followed by 2 h reperfusion, in anaesthetized Wistar male rats. Unfractionated bone marrow mononuclear cells (BMMNC) isolated from sibling Wistar male rat whole bone marrow were phenotyped by fluorescence activated cell sorting flowcytometry for the haematopoietic stem cell surface markers c-kit, CD34, CD45 and CD133. Animals subjected to regional myocardial reperfusion injury received either 10 million BMMNC or BMMNC supernatant (BMS); both were collected in 0.5 ml phosphate-buffered saline and delivered by intravenous bolus at the onset of reperfusion. The left ventricular region distal to the LAD occlusion point was excised for measurement of myocardial infarct size and proteomic analysis, which was used to identify whether there were any differences in myocardial proteins associated with intravenous injection of either BMMNC or BMS.
  
  
  RESULTS
  BMMNC were phenotyped to be c-kit(+) (7 ± 1%), CD34(+) (7 ± 1%), CD45(+) (54 ± 6%), CD133(+) (15 ± 1%). The supernatant reduced myocardial infarct size (BMS 34 ± 2%, n = 15 vs control 57 ± 2%, n = 7, P < 0.0001), which was comparable to the reduction in infarct size afforded by the injection of cells (BMMNC 33 ± 3% vs control 57 ± 2%, n = 10, P < 0.0001). Proteomics of hearts treated with either BMS or BMMNC demonstrated higher expression of (i) anti-apoptotic signal transduction protein: 14-3-3-epsilon (1.5-fold); (ii) anti-oxidants: peroxiredoxin-6 (2.1-fold); (iii) heat shock proteins: alpha B-crystallin (1.7-fold), heat shock protein 72 (2.8-fold), tumour necrosis factor receptor-1 associated protein (2.3-fold), ischaemia responsive protein-94 (1.6-fold); (iv) glycolytic protein: glyceraldehyde-3-phosphate dehydrogenase (2.3-fold); (v) mitochondrial respiratory proteins: mitochondrial aconitase (4.7-fold), voltage-dependent anion-selective channel protein-1 (VDAC-1) (2.7-fold).
  
  
  CONCLUSIONS
  Regional myocardial reperfusion injury can be attenuated by intravenous administration of either BMMNC or BMS at the onset of reperfusion, which suggests adult stem cells mediate non-regenerative cardioprotection.
authors.affiliation: Department of Cardiothoracic Surgery, London Chest Hospital, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK. 92myasin@gmail.com
authors.forename: Mohammed
authors.initials: M
authors.lastname: Yasin
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure; D001854:Bone Marrow Cells / Q000166:cytology*; D016026:Bone Marrow Transplantation / Q000379:methods*; D006339:Heart Rate; D016130:Immunophenotyping; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D020543:Proteome / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D033581:Stem Cell Transplantation / Q000379:methods*; D013234:Stem Cells / Q000166:cytology*; D016276:Ventricular Function / Q000502:physiology*
chemical_list: D020543:Proteome