Novel Bioceramic Urethral Bulking Agents Elicit Improved Host Tissue Responses in a Rat Model

Abstract

Objectives. To test the physical properties and host response to the bioceramic particles, silica-calcium phosphate (SCPC10) and Cristobalite, in a rat animal model and compare their biocompatibility to the current clinically utilized urethral bulking materials. Material and Methods. The novel bulking materials, SCPC10 and Cristobalite, were suspended in hyaluronic acid sodium salt and injected into the mid urethra of a rat. Additional animals were injected with bulking materials currently in clinical use. Physiological response was assessed using voiding trials, and host tissue response was evaluated using hard tissue histology and immunohistochemical analysis. Distant organs were evaluated for the presence of particles or their components. Results. Histological analysis of the urethral tissue five months after injection showed that both SCPC10 and Cristobalite induced a more robust fibroblastic and histiocytic reaction, promoting integration and encapsulation of the particle aggregates, leading to a larger bulking effect. Concentrations of Ca, Na, Si, and P ions in the experimental groups were comparable to control animals. Conclusions. This side-by-side examination of urethral bulking agents using a rat animal model and hard tissue histology techniques compared two newly developed bioactive ceramic particles to three of the currently used bulking agents. The local host tissue response and bulking effects of bioceramic particles were superior while also possessing a comparable safety profile.

In vivo molecular engineering of the urethra for treatment of stress incontinence using novel biomimetic proteoglycans

“…Studies of the bulking agents Coaptite, Bulkamid, and Macroplastique have revealed presence of giant cells, fibroblastic changes, and nodular tissue changes . Histological results of Coaptite showed aggregation occurring among bulking agent particles with local, nodular fibroblastic proliferation enclosed by giant cells . Host tissue response of Bulkamid included minor fibroblastic proliferation and nodular aggregates with bulking agent dispersed in the adventitia and submucosa .…”

“…Injection of Macroplastique resulted in a variation of particle aggregate sizes and shapes. The host tissue response included nodular aggregates and diffuse fibroblastic alterations . The use of BPG250 as a bulking agent resulted in no noticeable host tissue response after both 1‐ and 6‐week implantation periods.…”

“…Histological analysis revealed there was no morphological difference between control and BPG250 injected samples along with no inflammation or host tissue response detected in any of the samples. Studies of the bulking agents Coaptite, Bulkamid, and Macroplastique have revealed presence of giant cells, fibroblastic changes, and nodular tissue changes . Histological results of Coaptite showed aggregation occurring among bulking agent particles with local, nodular fibroblastic proliferation enclosed by giant cells .…”

“…nodular aggregates and diffuse fibroblastic alterations. 41 The use of BPG250 as a bulking agent resulted in no noticeable host tissue response after both 1-and 6-week implantation periods. It was hypothesized that incorporating BPG250 into the matrix would decrease the collagen density.…”

“…41 Host tissue response of Bulkamid included minor fibroblastic proliferation and nodular aggregates with bulking agent dispersed in the adventitia and submucosa. 41 Injection of Macroplastique resulted in a variation of particle aggregate sizes and shapes. The host tissue response included .…”