The current mainstay of treatment for urinary tract fistula is dependent on primary surgical repair despite issues of technical difficulties and high recurrence rates. We proposed a unique water-immiscible mussel protein-based bioadhesive (WIMBA) exhibiting strong underwater adhesion which was employed by adhesion strategies of marine organisms such as mussels and sandcastle worms. We previously reported the results of in vitro tests. We are going to report the results of preclinical in vivo tests.
Experimental iatrogenic vesicovaginal fistula was created using 16-week-old female New Zealand White Rabbits. A total of 44 rabbits, which were divided into four groups (11 glues, 11 sutures, 11 fibrin glue, 11 non-treated group) were used in the experiment. Each group received corresponding management, then the bladder and vagina were harvested en-bloc after 4 weeks of observation. Identification of recovery was performed by implementing cystometry using Indigo-carmine. (As a consecutive experiment, using 40kg Landrace/Yorkshire/Duroc breed female pigs which were divided into three groups (4 glues, 4 non-treated group, 2 sutures), the same procedure protocol was applied with the exception of an indwelling Foley catheter for 4 weeks. Identification of recovery was evaluated by cystography.
In a total 44 experimental rabbits, 4 out of 11 (36.7%) glue group and 5 out of 11 (45.4%) suture group were identified as successfully sealed and repaired in cystometry, respectively. The results of cystometry in rabbits using glue which closed up successfully, showed maximum pressure 35cm/H2O - maximum volume 229.3cc. In the suture group, maximum pressure and maximum volume were 54 cm/H2O - 135cc. Both fibrin glue group and non-treated group were unsuccessful. In subsequent experiments with pigs, the glue-treated group and the suture group exhibited 75% (3 out of 4) and 50% (1 out of 2) of success rate, respectively. In contrast, all of the non-treated group showed leakage through the fistula tract upon cystography.
Good performances of the developed biocompatible WIMBA was confirmed in in vivo fistulas model. Collectively, WIMBA could be used as a promising sealant for urinary fistula with further expansion to diverse internal body applications.