Table 4.
Preclinical studies using rat MI models to repair the ischemic tissue.
| Conductive Substrate |
Outcomes |
|---|---|
| Chitosan, PANI patch [52] | CV increased from 24.3 cm/s in the apex of the MI zone to 30.1 cm/s after applying the conductive patch. |
| Chitosan, PANI auxetic patch [104] | Minimal in vivo fibrotic response, good adhesion with the heart wall, no significant improvements in the cardiac functions though. |
| Alginate, PPy hydrogel [98] |
Conductive hydrogel injected hearts: Increased angiogenesis with arteriole density of 33 arteriole/µm2, five weeks post-injection. PBS injected hearts: low arteriole density of 21 arteriole/µm2. |
| Chitosan, PPy hydrogel [25] |
Conductive hydrogel injected hearts: EF/FS improved to 67%/34%, QRS/QT intervals reduced to 13/42 ms, and high CV of 62 cm/s, three months post-injection. Saline injected hearts: EF/FS was around 53%/25%, prolonged QRS/QT intervals of 17/70 ms, CV dropped to 43 cm/s. |
| Chitosan, PPy hydrogel [68] |
Improved electrical signal conduction in the infarcted zone with reduced QRS intervals. |
| Chitosan, PPy patch [72] |
Patch implanted hearts: Enhanced angiogenesis with 180 blood vessels/mm2, tissue regeneration area of 0.3 µm2, four weeks post-implantation. Chitosan injected hearts: Reduced angiogenesis with 68 blood vessels/mm2 and tissue regeneration area of 0.2 µm2. |
| PPy, HPAE, gelatin hydrogel [74] |
Conductive hydrogel injected hearts: EF/FS improved to 56%/31%, EDV/ESV to 325/150 µL, QRS interval reduced to 16 ms, after four weeks of injection. MI hearts: EF/FS dropped to 29%/15%, EDV/ESV to 525/420 µL, prolonged QRS of 40 ms. |
| PPy, chitosan hydrogel [93] |
Conductive hydrogel injected hearts: Improved longitudinal CV of 74.3 cm/s through the scar tissue after seven days of injection, shorter QRS interval of 18.6 ms, four weeks post-injection. Saline injected hearts: longitudinal CV dropped to 57.7 cm/s, prolonged QRS interval of 23.7 ms. |
| PAMB-G hydrogel [94] |
Conductive hydrogel injected hearts: Regional field potential increased to 1.5 mV and CV to 40 cm/s in the scar tissue, EF/EF improved to 67%/31%, LVIDs and LVIDd reduced to 6.2 mm and 8.7 mm, respectively, four weeks post-injection. Gelatin injected hearts: Regional field potential was around 0.7 mV with a slow CV of 27 cm/s, EF/FS dropped to 56%/23%, LVIDs and LVIDd were around 7 mm and 9.3 mm, respectively. |
| PAMB-G patch [95] |
Patch implanted hearts: Regional field potential increased to 1.9 mV with a CV of 39 cm/s in the scar tissue, reduced QRS intervals of 13 ms, EF/FS improved to 60%/28%, LVIDs and LVIDd reduced to 5.3 mm and 7.8 mm, respectively, four weeks post-implantation. Gelatin injected hearts: Reduced regional field potential of 0.7 mV with a slow CV of 19 cm/s, prolonged QRS intervals of 22 ms, EF/FS dropped to 57%/26%, LVIDs and LVIDs were around 5.6 mm and 8.2 mm. |
Abbreviations: EDV: end-diastolic volume, ESV: end-systolic volume, ESA: end-systolic area, EDA: end-diastolic area, LVEDD: left ventricular end-diastolic diameter, LVESD: left ventricular end-systolic diameter, LVIDs: left ventricular internal diameter at end-systole, LVIDd: left ventricular internal diameter at end-diastole, EF/FS: ejection fraction/fraction shortening, PEG-MEL: polyethylene glycol-melamine, PAMB-G: Poly-3-amino-4-methoxybenzoyic acid grafted on gelatin, HPAE: hyperbranched poly(amino ester).