Wound healing properties of a fibrin-based dermal replacement scaffold

When serious cutaneous injury occurs, the innate wound healing process attempts to restore the skin’s appearance and function. Wound healing outcome is affected by factors such as contraction, revascularisation, regeneration versus fibrosis and re-epithelialisation and is also strongly influenced by the pattern and extent of damage to the dermal layer. Dermal replacement scaffolds have been designed to substitute for lost tissue, provide a structure to promote dermal regeneration, and aid skin grafting, resulting in a superior healing outcome. In this study the wound healing properties of a novel fibrin-alginate dermal scaffold were assessed in the porcine wound healing model and also compared to two widely used dermal scaffolds and grafting alone. The fibrin-alginate scaffold, unlike the other scaffolds tested, is not used in combination with an overlying skin graft. Fibrin scaffold treated wounds showed increased, sustained superficial blood flow and reduced contraction during early healing while showing comparable wound closure, re-epithelialisation and final wound outcome to other treatments. The increase in early wound vascularisation coupled with a decrease in contraction and no requirement for a skin graft suggest that the fibrin-based scaffold could provide an effective, distinctive treatment option to improve healing outcomes in human patients.

Mechanical Properties of Human Concentrated Growth Factor (CGF) Membrane and the CGF Graft with Bone Morphogenetic Protein-2 (BMP-2) onto Periosteum of the Skull of Nude Mice

Concentrated growth factor (CGF) is 100% blood-derived, cross-linked fibrin glue with platelets and growth factors. Human CGF clot is transformed into membrane by a compression device, which has been widely used clinically. However, the mechanical properties of the CGF membranes have not been well characterized. The aims of this study were to measure the tensile strength of human CGF membrane and observe its behavior as a scaffold of BMP-2 in ectopic site over the skull. The tensile test of the full length was performed at the speed of 2mm/min. The CGF membrane (5 × 5 × 2 mm3) or the CGF/BMP-2 (1.0 μg) membrane was grafted onto the skull periosteum of nude mice (5-week-old, male), and harvested at 14 days after the graft. The appearance and size of the CGF membranes were almost same for 7 days by soaking at 4 °C in saline. The average values of the tensile strength at 0 day and 7 days were 0.24 MPa and 0.26 MPa, respectively. No significant differences of both the tensile strength and the elastic modulus were found among 0, 1, 3, and 7 days. Supra-periosteal bone induction was found at 14 days in the CGF/BMP-2, while the CGF alone did not induce bone. These results demonstrated that human CGF membrane could become a short-term, sticky fibrin scaffold for BMP-2, and might be preserved as auto-membranes for wound protection after the surgery.

Stem cells and repair of necrosis after dermolipectomy: a case study

Skin ulcers secondary to necrosis post-dermolipectomy occur infrequently. Despite their rarity and because of their complex pathopathophysiological nature, their resolution is a major challenge for plastic surgeons. This study is to recognise the safety and efficiency of use of CD34 stem cells (SC), obtained from the patient's bone marrow, within a solid autologous fibrin scaffold in the case of female patient with an ulcer with torpid evolution as a result of an abdominal dermolipectomy. The concept was to regenerate the affected tissue, and to induce and promote the formation of granulation tissue that is compact enough to stimulate repair by secondary intention or facilitating surgical closure. We applied a technique under specific protocols to obtain the stem cells. The healing technique—the application of CD34 stem cells without any surgical intervention—was applied at two ambulatory sessions. There were no complications or concomitant infections, and recovery was complete within five weeks via secondary intention healing, achieving a significant and satisfactory healing response in the patient, improving both her physical and mental health. In this case study, CD34 stem cells were used successfully in the treatment of a hard-to-heal ulcer. It is necessary to carry out further investigations with a greater number of patients to substantiate the use of this intervention in patients with hard-to-heal wounds.

390 Characterisation of a Platelet Rich Fibrin Membrane and Formation of an Autologous Fibrin Mesh

Aim Platelet-rich fibrin (PRF) is a three-dimensional fibrin scaffold with associated platelets and leukocytes which releases high quantities of growth factors over a sustained period of time. PRF has shown promising clinical results in promoting wound healing and tissue regeneration. The aims of this feasibility study were to establish optimal spinning methods for production of PRF, to quantify the production of vascular endothelial growth factor (VEGF) by PRF and to explore new vehicles of clinical PRF delivery. Method Assessment of optimal production involved comparisons between Protocol 1 (EDTA bottle) and Protocol 2 (no additive) at three different centrifugation forces: 400g, 1000g and 1700g. VEGF production was analysed using ELISA with varied incubation periods and PRF plug segments. Novel methods for PRF delivery were explored using surgical sutures and a Zimmer® Skin Graft Mesher. Results Protocol 2 demonstrated shorter average time to blood draw (9.8s compared to 13.6s) and to centrifuge (25.5s compared to 33.1s) with a decreased range of values. All PRF segments exhibited a positive correlation between incubation time and amount of VEGF produced with the bottom segments producing on average more VEGF. A segment of the fibrin plug was successfully secured on a suture and meshed in a 1:1.5 ratio. Conclusions PRF production can be optimised using blood bottles with no additive and high centrifugation forces. VEGF production by PRF peaks at 120 hours with the bottom PRF segment exhibiting the highest rate of production. The first description of a PRF mesh enables new clinical applications.

Prospective cohort study of regenerative potential of non vital immature permanent maxillary central incisors using platelet rich fibrin scaffold

Regenerative endodontic procedures have gained momentum as a treatment modality of young immature permanent teeth. Literature reports reveal that platelet-rich fibrin (PRF) stimulates growth factors and induces regeneration. This study was undertaken to assess the regenerative potential of non-vital immature permanent maxillary central incisors using PRF with a follow-up for 2 yrs. 19 patients in the age group of 9–25 yrs with immature, non-vital permanent maxillary central incisors (n = 23) with/without signs and/or symptoms of periapical pathosis and open apex were included in this study. In the first appointment, access opening, canal disinfection and triple antibiotic paste placement were done. In the subsequent visit, PRF was prepared and placed inside the canal. Access was sealed with Mineral trioxide aggregate plug and composite. The patient was reviewed up to 24 mths. The mean difference was statistically analyzed using Friedman test followed by Dunn post hoc test and adjusted by Bonferroni correction (p < 0.05). As per AAE guidelines, the primary and secondary goals were achieved. A significant (p < 0.001) gradual increase in the root length, thickness of dentinal walls and decrease in apical diameter were observed. Within the limitations of this study, PRF placement was clinically and radiographically effective in inducing regeneration of non-vital immature permanent teeth.

Functional tissue-engineered bone-like graft made of a fibrin scaffold and TG2 gene-modified EMSCs for bone defect repair

The transplantation of tissue-engineered scaffolds with stem cells is a promising therapeutic approach for bone defect repair. To improve the therapeutic efficacy of this approach, in this study, a novel biofunctional live tissue-engineered bone-like graft was designed and constructed using a fibrin scaffold loaded with TG2 gene-modified ectomesenchymal stem cells (TG2-EMSCs) derived from nasal respiratory mucosa for bone defect repair. Autocalcification of the cell-free fibrin gel in osteogenic medium with additional alkaline phosphatase (ALP) and the osteogenic differentiation of TG2-EMSCs on the fibrin scaffold were assessed in vitro. The results indicated that the cell-free fibrin gel could autocalcify in the osteogenic medium with ALP and that the overexpression of TG2 by TG2-EMSCs could promote the osteogenic differentiation of these stem cells in the fibrin scaffold. Moreover, TG2 could enhance the deposition of extracellular matrix proteins in the fibrin scaffold, followed by calcification of the bone matrix in vitro. After transplantation into critical-sized cranial defects in rats, the functional tissue-engineered bone-like grafts improved bone regeneration. These results indicate that this tissue-engineered bone-like graft could improve the process of bone defect repair.

Regenerative Potential of Non-Vital Immature Permanent Maxillary Central Incisors using Platelet Rich Fibrin Scaffold- A Prospective Cohort Study.

Regenerative endodontic procedures has gained momentum as a treatment modality of young immature permanent teeth. Literature reports reveal that platelet rich fibrin (PRF) stimulates growth factors and induces regeneration. This study was undertaken to assess the regenerative potential of non-vital immature permanent maxillary central incisors using PRF with a follow up for 2yrs. 19 patients in the age group of 9-25yrs with immature, non-vital permanent maxillary central incisors (n=23) with/without signs and/or symptoms of periapical pathosis and open apex were included in this study. In the first appointment, access opening, canal disinfection and triple antibiotic paste placement was done. In the subsequent visit, PRF was prepared and placed inside the canal. Access was sealed with Mineral trioxide aggregate plug and composite. The patient was reviewed upto 24mths. The mean difference was statistically analysed using Friedman test followed by Dunn post hoc test and adjusted by Bonferroni correction (p<0.05). As per AAE guidelines, the primary and secondary goals were achieved. A significant (p<0.001) gradual increase in the root length, thickness of dentinal walls and decrease in apical diameter were observed. Within the limitations of this study, PRF placement was clinically and radiographically effective in inducing regeneration of non-vital immature permanent teeth.