SUNRISE, Fla., July 24 Results of a preclinicalstudy involving the injection of myoblasts modified to express stromal derivedfactor-1(alpha) protein (SDF-1) into the scar tissue of the myocardium ofrats, which suggest improved heart function, were recently presented at twoscientific meetings -- the International Society for Magnetic Resonance inMedicine (ISMRM) in Toronto, and the American Society of Gene Therapy Meeting(ASGT) in Boston.
The data, presented by Bijoy Thattaliyath, MD, Post-doctoral Associate,Department of Pediatric Cardiology, University of Florida Health ScienceCenter, showed a decrease of 0.02ml in end systolic volume (0.13ml to 0.11ml)and a 38 percent increase in stroke volume (0.31 ml to 0.43 ml) from threeweeks post-myocardial infarction (MI, heart attack) to eight weeks post-celltransplantation, as presented in one of the SDF-1 modified myoblast (SDF-MB)transplanted animals. These results are indicative of 'positive remodeling',or return to normal heart function in the same period. Similar results werefound in other study animals. Histopathology confirmed that myoblastsexpressing SDF-1 resulted in increased muscle and blood vessel formation inthe damaged areas of the hearts, which was not observed in the control.
Additionally, there was an 11.7 percent plus or minus 2.9 percent (p=0.02)absolute improvement in ejection fraction between three weeks post-MI andeight weeks post-cell transplantation in the SDF-MB treated animals. Bycomparison, and as anticipated, the control arm worsened in the same period.Ejection fraction is the percentage of blood pumped out of the heart's leftventricle with every heartbeat into the body's vasculature. A higher percentejection fraction means more efficient heart function.
"The study data suggest that SDF-1 modified myoblasts contribute togreater improvement in cardiac function after transplantation compared tonon-modified myoblasts," said Dr. Thattaliyath. "This is a significant andencouraging finding, which adds to the growing body of investigationalevidence of using autologous myoblasts in the treatment of congestive heartfailure and opens the possibility of further study of MyoCell(R) ClinicalTherapy."
SDF-1 is a protein with multiple perceived benefits, includingangiogenesis (formation of new blood vessels which can provide nutrients tonewly engrafted cells) and stem cell homing (attraction of other stem cells totransplantation site for the purpose of helping with the healing process).
The addition of the SDF-1 protein to MyoCell(R) autologous cell therapyresults in a genetic modification that may further assist in future treatmentfor patients suffering from congestive heart failure. Bioheart obtained aworldwide exclusive license from The Cleveland Clinic to patent applicationscovering certain methods involving SDF-1 filed in the United States andcertain foreign countries.
The study, conducted at the University of Florida and partially funded byBioheart, focused on two primary hypotheses:
-- An increased expression of SDF-1 in the damaged myocardium shouldprovide a strong homing signal for endogenous stem cells involved inmyocardial repair.
-- SDF-1 modified myoblasts (SDF-MB) could undergo differentiation in thecardiac environment and assist myocardial performance, and provide acontinuous source of SDF-1.
Study objectives included assessment of cardiac function following onsetof MI, assessment of cardiac function in the presence and absence of SDF-1 andan assessment of the distribution and phenotype of the transplanted skeletalmyoblasts in a total of seven differentiated study groups of approximatelyfive subjects each. MRI assessments were conducted at one, four and eightweeks after the myoblast transplantation.
MyoCell(R) Clinical Therapy is currently being investigated in MARVEL(1),a randomized, double-blind, place