Evolution of a concept with enzymatic debridement and autologous in situ cell and platelet-rich fibrin therapy (BroKerF)

Background Deep partial-thickness burns are traditionally treated by tangential excision and split thickness skin graft (STSG) coverage. STSGs create donor site morbidity and increase the wound surface in burn patients. Herein, we present a novel concept consisting of enzymatic debridement of deep partial-thickness burns followed by co-delivery of autologous keratinocyte suspension and plated-rich fibrin (PRF) or fibrin glue. Material and methods In a retrospective case study, patients with deep partial-thickness burns treated with enzymatic debridement and autologous cell therapy combined with PRF or fibrin glue (BroKerF) between 2017 and 2018 were analysed. BroKerF was applied to up to 15% total body surface area (TBSA); larger injuries were combined with surgical excision and skin grafting. Exclusion criteria were age <18 or >70 years, I°, IIa°-only, III° burns and loss of follow-up. Results A total of 20 patients with burn injuries of 16.8% ± 10.3% TBSA and mean Abbreviated Burn Severity Score 5.45 ± 1.8 were identified. Of the patients, 65% (n = 13) were treated with PRF, while 35% (n = 7) were treated with fibrin glue. The mean area treated with BroKerF was 7.5% ± 0.05% TBSA, mean time to full epithelialization was 21.06 ± 9.2 days and mean hospitalization time was 24.7 ± 14.4 days. Of the patients, 35% (n = 7) needed additional STSG, 43% (n = 3) of whom had biopsy-proven wound infections. Conclusion BroKerF is an innovative treatment strategy, which, in our opinion, will show its efficacy when higher standardization is achieved. The combination of selective debridement and autologous skin cells in a fibrin matrix combines regenerative measures for burn treatment. Lay Summary Patients suffering from large burn wounds often require the use of large skin grafts to bring burned areas to heal. Before the application of skin grafts, the burned skin must be removed either by surgery or using enzymatic agents. In this article, we describe a method where small areas of skin are taken and skin cells are extracted and sprayed on wound areas that were treated with an enzymatic agent. The cells are held in place by a substance extracted from patients’ blood (PRF) that is sprayed on the wound together with the skin cells. We believe this technique can be helpful to reduce the need of skin grafts in burned patients and improve the healing process.

Fabrication, characterization and evaluation of the efficacy of gelatin/hyaluronic acid microporous scaffolds suffused with aloe-vera in a rat burn model

Burn induced injuries are commonly encountered in civilian and military settings, leading to severe morbidity and mortality. Objective of this study was to construct microporous bioactive scaffolds of gelatin-hyaluronic acid suffused with aloe-vera gel (Gela/HA/AvG), and to evaluate their efficacy in healing partial-thickness burn wounds. Scaffolds were characterized using Fourier transform-infrared spectroscopy, Scanning electron microscopy, and Thermo-gravimetric analysis to understand intermolecular interactions and morphological characteristics. In-vitro fluid uptake ability and hemolytic index of test scaffolds were also determined. In-vitro collagenase digestion was done to assess biodegradability of scaffolds. Wound retraction studies were carried out in Sprague Dawley rats inflicted with partial-thickness burn wounds to assess and compare efficacy of optimized scaffolds with respect to negative and positive control groups. In-vivo gamma scintigraphy using Technetium-99m labeled Immunoglobulin-G ( 99m Tc-IgG) as imaging agent was also performed to validate efficacy results. Histological and immunohistochemical comparison between groups was also made. Scaffolds exhibited mircoporous structure, with pore size getting reduced from 41.3 ± 4.3 µm to 30.49 ± 5.7 µm when gelatin conc. was varied from 1% to 5%. Optimized test scaffolds showed sustained in-vitro swelling behavior, were biodegradable and showed hemolytic index in range of 2.4–4.3%. Wound retraction study along with in-vivo gamma scintigraphy indicated that Gela/HA/AvG scaffolds were not only able to reduce local inflammation faster but also accelerated dermis regeneration. Immunohistochemical analysis, in terms of expression levels of epidermal growth factor and fibroblast growth factor-2 also corroborated in-vivo efficacy findings. Gela/HA/AvG scaffolds, therefore, can potentially be developed into an effective dermal regeneration template for partial-thickness burn wounds.

Treatment With Glycogen Synthase Kinase 3β Inhibitor Decreases Apoptotic and Autophagic Reactions in Rat Rotator Cuff Tears

Background: Apoptosis and autophagy are known to be correlated with the extent of damage in torn rotator cuffs, and there is no biological evidence for self-recovery or healing of the rotator cuff tear. Purpose: To establish in a rat model of partial- and full-thickness rotator cuff tears how a glycogen synthase kinase 3β (GSK-3β) inhibitor affects the expression of apoptotic and autophagic markers. Study Design: Controlled laboratory study. Methods: Twelve-week-old Sprague Dawley rats were divided into 3 groups (n = 16 per group). Group 1 acted as the control, with no treatment; group 2 received partial-thickness (right side) and full-thickness (left side) rotator cuff tears only; and group 3 received the same rotator cuff injuries, with GSK-3β inhibitor injected afterward. The tendons from each group were harvested 42 days after surgery. Evaluation of gene expression, immunohistochemistry, and TUNEL staining (terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling) were performed for the following markers: caspases 3, 8, and 9 as well as Bcl-2 (B-cell lymphoma 2); BAX (Bcl-2-associated X protein); beclin 1; p53; and GSK-3β; which represented apoptotic and autophagic reactions. Statistical analysis was performed using 1-way analysis of variance. Results: In the group 2 rats with partial- and full-thickness tears, there were significant increases in the mRNA levels (fold changes) of all 8 markers as compared with group 1 (control). All these increased markers showed significant downregulation by the GSK-3β inhibitor in partial-thickness tears. However, the response to the GSK-3β inhibitor in full-thickness tears was not as prominent as in partial-thickness tears. The number of TUNEL-positive cells in group 2 (partial, 35.08% ± 1.625% [mean ± SE]; full, 46.92% ± 1.319%) was significantly higher than in group 1 (18.02% ± 1.036%; P < .01) and group 3 (partial, 28.04% ± 2.607% [ P < .01]; full, 38.97% ± 2.772% [ P < .01]), and immunohistochemistry revealed increased expression of all the markers in group 2 as compared with control. Conclusion: The apoptotic and autophagic activity induced in a rat model of an acute rotator cuff tear was downregulated after treatment with a GSK-3β inhibitor, particularly with partial-thickness rotator cuff tears. Clinical Relevance: A GSK-3β inhibitor may be able to modulate deterioration in a torn rotator cuff.

Accuracy and safety of partial thickness femtosecond laser radial and arcuate keratotomy incisions in porcine eyes

Background To evaluate the accuracy and safety of micro radial and arcuate keratotomy incisions constructed by a femtosecond laser system with a curved contact patient interface in porcine eyes. Methods Partial thickness micro radial and arcuate keratotomy incisions were constructed in porcine eyes with a femtosecond laser system and evaluated for precision of depth, quality, and consistency. Optical coherence tomography was used to determine the accuracy and precision of incision depth. Corneal endothelial safety was assessed by a fluorescent live/dead cell viability assay to demonstrate laser-induced endothelial cell loss. Quality was evaluated by ease of opening and examination of interfaces. Results In two micro radial incision groups, intended incision depths of 50% and 80% resulted in mean achieved depths of 50.01% and 77.69%, respectively. In three arcuate incision groups, intended incision depths of 80%, 600 μm or 100 μm residual uncut bed thickness resulted in mean achieved depths of 80.16%, 603.03 μm and residual bed of 115 μm, respectively. No loss of endothelial cell density occurred when the residual corneal bed was maintained at a minimum of 85–116 µm. The incisions were easy to open, and interfaces were smooth. Conclusions A femtosecond laser system with curved contact interface created precise and reproducible micro radial and arcuate keratotomy incisions. Accuracy and precision of the incision depth and preservation of endothelial cell density demonstrated the effectiveness and safety of the system.

Biceps Augmentation Outperforms Tear Completion Repair or In Situ Repair for Bursal-Sided Partial-Thickness Rotator Cuff Tears in a Rabbit Model

Background: There is an ongoing debate on the treatment of bursal-sided partial-thickness rotator cuff tears (PTRCTs), including ideal repair techniques. Augmentation using a collagen patch has been introduced as a new surgical approach to treat PTRCTs, while the effect of autogenous biceps augmentation (BA) has not been investigated. Purpose: To analyze the effects of BA on bursal-sided PTRCTs and compare its histological and biomechanical results with those of tear completion followed by repair and in situ repair (ISR). Study Design: Controlled laboratory study. Methods: Unilateral chronic PTRCTs were created in 96 mature New Zealand White rabbits, which were randomly divided into 4 groups: no repair, tear completion repair (TCR), ISR, and BA. A new bicipital groove was fabricated in BA for the biceps tendon that was transferred to augment the bursal-sided PTRCT repair. In each group, we sacrificed 6 rabbits for biomechanical testing of the whole tendon-to-bone complex (WTBC) and 6 for histological evaluation of bursal- and articular-sided layers at 6 and 12 weeks postoperatively. Healing responses between the biceps and new bicipital groove in the BA group were determined using histological analysis, and final groove morphologies were evaluated using micro–computed tomography. Results: The remaining tendon and enthesis in bursal-sided PTRCTs progressively degenerated over time. WTBCs of ISR exhibited a larger failure load than those of TCR, although better healing properties in the bursal-sided repaired site were achieved using TCR based on histological scores and superior articular-sided histological scores were observed using ISR. However, WTBCs of BA displayed the best biomechanical results and superior histological scores for bursal- and articular-sided regions. The new bicipital groove in BA remodeled over time and formed similar morphologies to a native groove, which provided a mature bone bed for transferred biceps tendon healing to augment bursal-sided PTRCTs. Conclusion: BA achieved better biomechanical and histological results for repairing bursal-sided PTRCTs as compared with TCR and ISR. When compared with that of TCR, the WTBC of ISR exhibited a higher failure load, showing histological superiority in the articular-sided repair and inferiority in the bursal-sided repair. Clinical Relevance: BA may be an approach to improve bursal-sided PTRCT repair in humans, which warrants further clinical investigation.