The Collagen Origin Influences the Degradation Kinetics of Guided Bone Regeneration Membranes

Collagen membranes are currently the most widely used membranes for guided bone regeneration; however, their rapid degradation kinetics means that the barrier function may not remain for enough time to permit tissue regeneration to happen. The origin of collagen may have an important effect on the resistance to degradation. The aim of this study was to investigate the biodegradation pattern of five collagen membranes from different origins: Biocollagen, Heart, Evolution X-fine, CopiOs and Parasorb Resodont. Membranes samples were submitted to different degradation tests: (1) hydrolytic degradation in phosphate buffer saline solution, (2) bacterial collagenase from Clostridium histolyticum solution, and (3) enzyme resistance using a 0.25% porcine trypsin solution. Immersion periods from 1 up to 50 days were performed. At each time point, thickness and weight measurements were performed with a digital caliper and an analytic microbalance, respectively. ANOVA and Student–Newman–Keuls tests were used for comparisons (p < 0.05). Differences between time-points within the same membranes and solutions were assessed by pair-wise comparisons (p < 0.001). The Evolution X-fine collagen membrane from porcine pericardium attained the highest resistance to all of the degradation tests. Biocollagen and Parasorb Resodont, both from equine origin, experienced the greatest degradation when immersed in PBS, trypsin and C. histolyticum during challenge tests. The bacterial collagenase solution was shown to be the most aggressive testing method.

In Vitro Biodegradation Pattern of Collagen Matrices for Soft Tissue Augmentation

Collagen matrices have become a great alternative to the use of connective tissue grafts for soft tissue augmentation procedures. One of the main problems with these matrices is their volume instability and rapid degradation. This study has been designed with the objective of examining the degradation of three matrices over time. For this purpose, pieces of 10 × 10 mm2 of Fibro-Gide, Mucograft and Mucoderm were submitted to three different degradation tests—(1) hydrolytic degradation in phosphate buffer solution (PBS); (2) enzyme resistance, using a 0.25% porcine trypsin solution; and (3) bacterial collagenase resistance (Clostridium histolyticum)—over different immersion periods of up to 50 days. Weight measurements were performed with an analytic microbalance. Thickness was measured with a digital caliper. A stereomicroscope was used to obtain the matrices’ images. ANOVA and Student–Newman–Keuls tests were used for mean comparisons (p < 0.05), except when analyzing differences between time-points within the same matrix and solution, where pair-wise comparisons were applied (p < 0.001). Fibro-Gide attained the highest resistance to all degradation challenges. The bacterial collagenase solution was shown to constitute the most aggressive test as all matrices presented 100% degradation before 14 days of storage.

Collagenase-Expressing Salmonella Targets Major Collagens in Pancreatic Cancer Leading to Reductions in Immunosuppressive Subsets and Tumor Growth

Therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) can be attributed, in part, to a dense extracellular matrix containing excessive collagen deposition. Here, we describe a novel Salmonella typhimurium (ST) vector expressing the bacterial collagenase Streptomyces omiyaensis trypsin (SOT), a serine protease known to hydrolyze collagens I and IV, which are predominantly found in PDAC. Utilizing aggressive models of PDAC, we show that ST-SOT selectively degrades intratumoral collagen leading to decreases in immunosuppressive subsets, tumor proliferation and viability. Ultimately, we found that ST-SOT treatment significantly modifies the intratumoral immune landscape to generate a microenvironment that may be more conducive to immunotherapy.

Collagenase-Expressing Salmonella Targets Major Collagens in Pancreatic Cancer and Improves Immune Checkpoint Blockade

Therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) can be attributed, in part, to a dense extracellular matrix containing excessive collagen deposition. Here, we describe a novel Salmonella typhimurium (ST) vector expressing the bacterial collagenase Streptomyces omiyaensis trypsin (SOT), a serine protease known to hydrolyze collagens I and IV, which are predominantly found in PDAC. Utilizing aggressive models of PDAC, we show that ST-SOT selectively degrades intratumoral collagen leading to enhancement of immune checkpoint blockade (ICB) therapy in tumor-bearing mice. Ultimately, we found that ST-SOT treatment significantly modifies the intratumoral immune landscape to generate a microenvironment more conducive to ICB.

Influence of Activators and Inhibitors on the Collagenase with Collagen Interaction Monitored by Dynamic Light Scattering in Solutions

Real–time digestion of type I collagen molecules by bacterial collagenase from Clostridium histolyticum has been monitored using Dynamic Light Scattering method. Time dependencies for translation diffusion coefficient (Dt) and hydrodynamic radius (RH) on were obtained for pure “collagen + collagenase” Tris–HCl buffer solution at different temperatures and for solutions with added CaCl2, ZnCl2 and MgCl2 and EDTA. It was shown that digestion of type I collagen molecules by bacterial collagenase is the first-order reaction. Reaction rate coefficients were calculated.

EARLY EXCISION AND GRAFTING VERSUS CONSERVATIVE TREATMENT IN THE MANAGEMENT OF MAJOR BURNS: A COMPARATIVE STUDY.

Background : 1 Full thickness burns lose their eschar in 2-6 weeks through bacterial collagenase production and daily mechanical debridement . The practice of leaving these dead tissues only serves as a nidus for infection that can lead to the patient's death. Hence the standard procedure is surgical removal of eschar with grafting techniques. Methods:Atotal of 50 patients divided in 25 patients in each group were included first group was managed conservatively and second underwent th early excision and grafting within 5 day upto 10% TBSA. Results: Early excision and grafting patients required significantly (p=0.04) more blood transfusions than conservatively managed patients. The mean hospital stay was significantly (p=0.05) lower by 10 days in early excision and grafting than conservatively managed. Conclusion : Early Excision and Grafting group was found to have significantly shorter hospital stay with decresed painful debridement but required more blood transfusions than conservatively managed patients.

EARLY EXCISION AND GRAFTING VERSUS CONSERVATIVE TREATMENT IN THE MANAGEMENT OF MAJOR BURNS: A COMPARATIVE STUDY

Background : 1 Full thickness burns lose their eschar in 2-6 weeks through bacterial collagenase production and daily mechanical debridement . The practice of leaving these dead tissues only serves as a nidus for infection that can lead to the patient's death. Hence the standard procedure is surgical removal of eschar with grafting techniques. Methods:Atotal of 50 patients divided in 25 patients in each group were included first group was managed conservatively and second underwent th early excision and grafting within 5 day upto 10% TBSA. Results: Early excision and grafting patients required significantly (p=0.04) more blood transfusions than conservatively managed patients. The mean hospital stay was significantly (p=0.05) lower by 10 days in early excision and grafting than conservatively managed. Conclusion : Early Excision and Grafting group was found to have significantly shorter hospital stay with decresed painful debridement but required more blood transfusions than conservatively managed patients.