Bioresorbable Gelatin Microspheres for Temporary Transarterial Embolization: Feasibility Study in Porcine Kidney Model

Purpose: To evaluate the in vivo characteristics, degradation profile, and feasibility of a bioresorbable gelatin microsphere (R-GM) for controlled, temporary embolization in a porcine kidney model. Materials and Methods: Six male farm pigs underwent transarterial embolization of the artery to the left kidney upper pole (LKUP) and to the right kidney upper pole (RKUP) using 100–300-µm-sized tris-acryl gelatin microsphere (T-GM) and R-GM, respectively. Follow-up angiography was performed in 2 h, 2 days, 1 week, 3 weeks, and 16 weeks to assess the presence of recanalization of the embolized arteries. Each pig was killed at each time point, and histopathologic analysis was performed to evaluate the presence of embolic agents, inflammatory reaction, and degree of tissue damage of the embolized renal segment. Results: On 2 h post-angiogram, LKUP was occluded, and RKUP was fully recanalized in all pigs. Parenchymal staining of the RKUP area was normalized at 2 h post-embolization and maintained until the 16-week follow-up. No R-GM or fragments were found in any specimens except for 2 days, but tris-acryl microspheres were observed in tissues with infarction with inflammatory changes until the 16-week follow-up. The levels of macrophages, giant cells, neovascularization, and fibrosis were higher in the LKUP compared to the RKUP at 1 week to 16 weeks (all, p < 0.05). The LKUP had a higher infarct area up to 97.17 ± 0.64% at 1 week compared to the RKUP, which had no infarction (0 ± 0%). Conclusion: Temporary transarterial embolization using R-GM was feasible in vivo, achieving temporary occlusion followed by complete recanalization of the embolized vessel and minimal tissue damage. Levels of Evidence: No levels of Evidence (Experimental study).