Biomedical subjects

Christopher Kim

Publications and source records attributed to Christopher Kim.

3 recordsLinked to original sources

PubMed2005

Maximizing ventricular function with multimodal cell-based gene therapy.

BACKGROUND: Angiogenesis is enhanced after transplantation of vascular endothelial growth factor (VEGF)-expressing cells into a myocardial scar. Insulin-like growth factor I (IGF-I) may induce hypertrophy and inhibit apoptosis. We evaluated the effect of cell-based IGF-I and VEGF multigene therapy on left ventricular (LV) function, cell survival, and apoptosis after bone marrow cell (BMC) transplantation. METHODS AND RESULTS: Female Lewis rats underwent left anterior descending ligation 3 weeks before transplantation with male donor BMC, BMC transfected with VEGF (BMC+VEGF), IGF-I (BMC+IGF-I), VEGF and IGF-I (BMC+VEGF+IGF-I), or medium without cells (control) (n=4 per group x 5 groups x 4 time points). Three days and 1, 2, and 4 weeks after transplantation, VEGF and IGF-I expression was quantitated by real-time polymerase chain reaction, cell survival by polymerase chain reaction for sry2, apoptosis by TUNEL staining, LV function by echocardiography and myosin heavy chain, and light chain and troponin I by Western blot. One week after transplantation, IGF-I expression in the scar and border zone was greatest in BMC+IGF-I and BMC+VEGF+IGF-I rats (P<0.05). VEGF expression in the scar and border zone was greatest in BMC+VEGF and BMC+VEGF+IGF-I hearts (P<0.05). Transplanted cell survival was lowest in BMC, intermediate in BMC+VEGF and BMC+IGF-I, and greatest in BMC+VEGF+IGF-I (P<0.05). Apoptotic indices were significantly reduced in BMC+VEGF+IGF-I, BMC+VEGF, and BMC+IGF-I (P<0.05). Two and 4 weeks after transplantation, LV ejection fraction was lowest in control, intermediate in BMC, BMC+VEGF, and BMC+IGF-I, and greatest in BMC+VEGF+IGF-I (P<0.05). CONCLUSIONS: Transplantation of VEGF- and IGF-I-expressing BMC reduced apoptosis, maximized transplanted cell survival, and enhanced LV function. Multimodal cell-based gene therapy may maximize the benefits of cell transplantation.

Animals↗

PubMed2005

Increasing transplanted cell survival with cell-based angiogenic gene therapy.

BACKGROUND: The majority of cells transplanted into infarcted myocardium do not survive. Maximizing cell survival should maximize the efficacy of cell transplantation for myocardial repair. We evaluated the role of apoptosis in cell loss after transplantation and the effect of angiogenesis on apoptosis and overall cell survival. METHODS: Female Lewis rats underwent myocardial cryoinjury 3 weeks before transplantation with male heart cells (a mixed culture of cardiomyocytes, smooth muscle cells, endothelial cells, and fibroblasts), vascular endothelial growth factor-transfected heart cells, skeletal myoblasts, vascular endothelial growth factor-transfected skeletal myoblasts (n = 6 each), or medium (control, n = 5). One week later, transplanted cell survival and apoptosis were quantitated by real-time polymerase chain reaction for Y chromosomal deoxyribonucleic acid, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay and deoxyribonucleic acid fragmentation. RESULTS: Approximately one third of heart cells and skeletal myoblasts survived 1 week after transplantation, and one half of vascular endothelial growth factor-transfected heart cells and skeletal myoblasts survived to this time (p < 0.05). Apoptosis was greatest in heart cell and skeletal myoblast-transplanted hearts (p < 0.05), reduced in the vascular endothelial growth factor-transfected groups (p < 0.05) and lowest in controls. CONCLUSIONS: Ischemia and apoptosis both contribute to cell loss after transplantation. Transfection with vascular endothelial growth factor induced angiogenesis, which reduced both ischemic and apoptotic cell death. Our findings suggest that further strategies to reduce apoptosis may enhance the efficacy of cell transplantation in myocardial repair.

Animals↗

PubMed2003

Empirical analysis of transcriptional activity in the Arabidopsis genome.

Functional analysis of a genome requires accurate gene structure information and a complete gene inventory. A dual experimental strategy was used to verify and correct the initial genome sequence annotation of the reference plant Arabidopsis. Sequencing full-length cDNAs and hybridizations using RNA populations from various tissues to a set of high-density oligonucleotide arrays spanning the entire genome allowed the accurate annotation of thousands of gene structures. We identified 5817 novel transcription units, including a substantial amount of antisense gene transcription, and 40 genes within the genetically defined centromeres. This approach resulted in completion of approximately 30% of the Arabidopsis ORFeome as a resource for global functional experimentation of the plant proteome.

Arabidopsis↗