biostudies-literatureUnknown15(1)Iida JThis study explored the impact of hydrolyzed gelatin (HG) concentration on the retention and therapeutic efficacy of human iPS cell-derived cardiomyocytes (hiPSC-CMs) when injected into the myocardium. The solubility of HG allows precise control over its concentration, influencing the distribution and leakage of injected solutions, which may affect therapeutic outcomes. Using both ex vivo and in vivo rat models, we investigated how varying HG concentrations affect the retention of solution and diffusion within the myocardium. In ex vivo static rat hearts, 10% HG minimized leakage but allowed significant diffusion. However, in pulsating in vivo hearts, 20% HG provided the best retention. In a rat myocardial infarction model, hiPSC-CMs suspended in 20% HG resulted in the highest cell retentiScientific reports4635https://www.ebi.ac.uk/biostudies/studies/S-EPMC11806045biostudies-literatureRetention of locally injected human iPS cell-derived cardiomyocytes into the myocardium using hydrolyzed gelatin.PMC11806045Maihemuti WMinatoya KMandai YMasumoto HMurata KHiraoka YHakamada KIida JKotani KfalseRetention of locally injected human iPS cell-derived cardiomyocytes into the myocardium using hydrolyzed gelatin.This study explored the impact of hydrolyzed gelatin (HG) concentration on the retention and therapeutic efficacy of human iPS cell-derived cardiomyocytes (hiPSC-CMs) when injected into the myocardium. The solubility of HG allows precise control over its concentration, influencing the distribution and leakage of injected solutions, which may affect therapeutic outcomes. Using both ex vivo and in vivo rat models, we investigated how varying HG concentrations affect the retention of solution and diffusion within the myocardium. In ex vivo static rat hearts, 10% HG minimized leakage but allowed significant diffusion. However, in pulsating in vivo hearts, 20% HG provided the best retention. In a rat myocardial infarction model, hiPSC-CMs suspended in 20% HG resulted in the highest cell retenti2025-01-01T00:00:00Z2025 Feb2025-04-04T01:32:33.696Z2025-04-04T01:32:33.696ZS-EPMC118060453992022810.1038/s41598-025-87885-w