Heat shock treatment enhances graft cell survival in skeletal myoblast transplantation to the heart.
BACKGROUND
Graft survival after skeletal myoblast transplantation is affected by various pathological processes caused by environmental stress. Heat shock is known to afford protection of several aspects of cell metabolism and function. We hypothesized that prior heat shock treatment of graft cells would improve their survival after cell transplantation.


RESULTS
L6 rat skeletal myoblasts expressing ss-galactosidase (ss-gal) were subjected to heat shock (42 degrees C, 1 hour). Increased expression of heat shock protein 72 was detected 24 hours later in the heat-shocked cells. After hypoxia-reoxygenation in vitro, lactate dehydrogenase leakage was significantly attenuated in the heat-shocked cells; in addition, the percentage of early apoptosis was lower in this group measured by flow cytometry with annexin V staining. For the in vivo study, 1 x 10(6) heat-shocked (hsCTx) or normal-cultured (CTx) myoblasts were infused into the explanted rat hearts through the coronary artery followed by heterotopic heart transplantation. ss-gal activity was significantly higher in the hsCTx group after cell transplantation, with an estimated 8 x 10(6) surviving cells per heart in the hsCTx group and 5 x 10(6) cells in the CTx group on day 28. Discrete loci of grafted cells were globally observed in the myocardium of the hsCTx and CTx groups, with a higher frequency in the hsCTx group. Surviving myoblasts occasionally differentiated into myotubes and had integrated with the native cardiomyocytes.


CONCLUSIONS
Heat-shocked skeletal myoblasts demonstrated improved tolerance to hypoxia-reoxygenation insult in vitro and enhanced survival when grafted into the heart. Heat shock treatment could be useful in improving graft cell survival in cell transplantation.
Suzuki
K
K
Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine at the Heart Science Centre, Harefield Hospital, Middlesex, UK. Ken.Suzuki@harefield.nthames.nhs.uk
Smolenski
R T
RT
Jayakumar
J
J
Murtuza
B
B
Brand
N J
NJ
Yacoub
M H
MH
D000818:Animals; D017209:Apoptosis; D015687:Cell Hypoxia / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D017077:Culture Media, Conditioned / Q000378:metabolism; D017930:Genes, Reporter / Q000235:genetics; D006085:Graft Survival / Q000502:physiology*; D050884:HSP72 Heat-Shock Proteins; D016027:Heart Transplantation; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D018869:Heat-Shock Response / Q000502:physiology*; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000637:transplantation*; D009206:Myocardium / Q000737:chemistry / Q000166:cytology*; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection; D016042:Transplantation, Heterotopic; D001616:beta-Galactosidase / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics
D017077:Culture Media, Conditioned; D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007770:L-Lactate Dehydrogenase; D001616:beta-Galactosidase; D010100:Oxygen