Effects of the Collagenase of the Bacteria Clostridium Histolyticum on the Development of Capsular Fibrosis after Insertion of Silicone Implants in Rats

• Applicant: Dr. Sebastian Fischer
• Subject Area: Gynaecology and Obstetrics ; Biomaterials
• Term: Funded in 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259236300

Augmentation mammaplasty with silicone implants reveals the most common aesthetic surgery worldwide. Even for reconstructive indications, thus breast cancer or congenital malformations, insertion of silicone implants is an effective and safe procedure to regain natural breast volume and shape. Nevertheless, long-term complications often influence reconstructive patients to decide for risky and more invasive autologous tissue transplantation. In this context capsular fibrosis is the most common and momentous complication after silicone breast augmentation. Based on a foreign body reaction, silicone provokes an excessive extracellular matrix formation, leading to palpable, visible and painful indurations of the female breast. Surgical resection of capsular tissue and implant exchange is currently the only sufficient therapy for capsular fibrosis. However, despite adequate surgery, risk of recurrence is up to 55%. Furthermore incidence of capsular fibrosis for reconstructive implantations after breast cancer is 5 fold higher compared to aesthetic augmentations. Consequently, for patients with state after capsular fibrosis or after breast cancer, silicone breast augmentation is often not recommended, making hazardous and more invasive autologous tissue transplantation the only reconstructive option. Development of a non-surgical treatment to overcome capsular fibrosis would directly influence therapeutic strategies of these reconstructive patients.Capsular fibrosis consists mainly of collagen, similar to Dupuytrens Disease, an excessive extracellular matrix formation of the palmar fascia, which leads to painfully palpable strands and flexing contracture of the fingers. Whereas surgical resection of fibrotic tissue was goldstandard for the treatment of Dupuytrens Disease, injection of a specific collagenase became more and more popular in the last few years. This collagenase degrades all collagen subtypes except of subtype 4, which is the main part of the basal lamina of vessels, nerves and tendons. Due to protection of these functional structures this specific collagenase can be injected safely and effectively into the palm making application into the female breast theoretically feasible.Aim of this study is to treat capsular fibrosis and to prevent its development with means of collagenase injection. Therefore we utilize an established rodent model with which we can create capsular fibrosis for in-vitro and in-vivo investigations. Due to cooperation with Harvard medical school, we have access to modern imaging methods and expert knowledge in the field of immunology. If this study proves beneficial effects in a rodent model, we plan further studies in a large animal model as well as ex-vivo applications into explanted human capsules.Successful injection of collagenase to overcome and prevent capsular fibrosis would save a few hundred thousand women surgical intervention and make silicone breast reconstruction after breast cancer more feasible.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Bohdan Pomahac