New biocompatible highly purified collagen gel for therapeutic renal artery embolization.

Objectives: To evaluate the effectiveness and safety of a new purified collagen gel with specific properties for renal artery embolization in an experimental model in dogs.

Methods: The new gel was prepared from type I bovine tendon collagen, highly purified to eliminate immunogenicity, and reconstituted through extensive dialysis in distilled water without the addition of glutaraldehyde. The study was conducted on 16 mongrel dogs that underwent random embolization of the renal artery. The dogs were divided into two groups: group 1 was killed after 2 days and group 2 after 21 days. The abdominal organs, lungs, and muscles of the posterior limbs were studied in detail and samples were taken for an anatomic-pathologic analysis.

Results: After embolization, uniform parenchymatosus ischemia and loose perirenal adhesions without significant volumetric changes were observed in group 1. A microscopic study revealed acidophilus amorphous and birefringent emboli filling the lumen of the renal artery and extending into the arterioles. The glomeruli and tubules showed early signs of diffused necrosis. In group 2, microscopic examination revealed endothelial proliferation around the emboli that had closely adhered to the arterial wall, with signs of fibroblastic proliferation within the emboli. In both groups, the abdominal organs, lungs, and muscles of the posterior limbs did not show signs of collagen migration.

Conclusions: Purified collagen gel effectively embolized the renal artery. The absence of collagen migration to other organs and posterior limbs suggests that this material can be safely used for organ embolization.