How miRNAs Regulate Schwann Cells during Peripheral Nerve Regeneration-A Systemic Review.

A growing body of studies indicate that small noncoding RNAs, especially microRNAs (miRNA), play a crucial role in response to peripheral nerve injuries. During Wallerian degeneration and regeneration processes, they orchestrate several pathways, in particular the MAPK, AKT, and EGR2 (KROX20) pathways. Certain miRNAs show specific expression profiles upon a nerve lesion correlating with the subsequent nerve regeneration stages such as dedifferentiation and with migration of Schwann cells, uptake of debris, neurite outgrowth and finally remyelination of regenerated axons. This review highlights (a) the specific expression profiles of miRNAs upon a nerve lesion and (b) how miRNAs regulate nerve regeneration by acting on distinct pathways and linked proteins. Shedding light on the role of miRNAs associated with peripheral nerve regeneration will help researchers to better understand the molecular mechanisms and deliver targets for precision medicine.

Reconstruction of Critical Nerve Defects Using Allogenic Nerve Tissue: A Review of Current Approaches.

Regardless of the nerve defect length, nerve injury is a debilitating condition for the affected patient that results in loss of sensory and motor function. These functional impairments can have a profound impact on the patient's quality of life. Surgical approaches for the treatment of short segment nerve defects are well-established. Autologous nerve transplantation, considered the gold standard, and the use of artificial nerve grafts are safe and successful procedures for short segment nerve defect reconstruction. Long segment nerve defects which extend 3.0 cm or more are more problematic for repair. Methods for reconstruction of long defects are limited. Artificial nerve grafts often fail to regenerate and autologous nerve grafts are limited in length and number. Cadaveric processed/unprocessed nerve allografts are a promising alternative in nerve surgery. This review gives a systematic overview on pre-clinical and clinical approaches in nerve allograft transplantation.

Synergistic Treatment of Infected Burn Wound Utilizing Maggot Debridement and Acellular Fish Skin Grafting-A Case Report.

Here, we report about a patient with a full-thickness burn injury of the left lower extremity with approximately 8% of total BSA affected. Initial therapy consisted of necrosectomy and wound coverage with split-thickness graft. The patient developed a wound infection with Pseudomonas aeruginosa, resulting in the failure of the skin graft to achieve complete healing. The case was further complicated by the patient's concurrent presentation of anemia, characterized by a hematocrit level of 19.8% on 11th day after admission. Additionally, the patient refused acceptance of any blood transfusion, adding a significant layer of complexity to the management strategy. In summary, the patient's critical state required an immediate intervention. Due to the contraindication for a further surgical debridement and autograft, we changed the treatment strategy to a conservative approach. First, the wound was debrided employing maggot therapy 17 days after admission. Subsequently, free soft tissue coverage was accomplished using decellularized fish skin dressings on 45th day. This approach yielded satisfactory wound closure. Following an approximately 2-month hospitalization period (52nd day after admission), the patient was discharged with a stable wound condition, nearing complete healing.

[Fasciocutaneous bridge flap to cover defects on the lower leg after compartment syndrome with a complication-prone course : An "almost" forgotten safe flap procedure]. / Fasziokutane Brückenlappenplastik zur Defektdeckung im Komplikationsfall am Unterschenkel nach Kompartmentsyndrom : Eine "fast" vergessene, sichere Lappenplastik.

This article reports on a complicated case of a soft tissue defect with challenging soft tissue coverage on the lower leg. After a lower leg fracture and treatment with a tibial nail, a 29-year-old man developed compartment syndrome due to massive secondary bleeding with a lesion of the common peroneal nerve and muscle necrosis around the fibular muscles. The initial coverage with split skin showed no tendency to heal, so the patient was admitted to this hospital with a soft tissue defect of approximately 25 cm × 10 cm on the lateral lower leg with an exposed tibia over a length of 15 cm. The primary attempt was coverage with a split-thickness skin graft after secondary granulation; however, due to the previously damaged vascular supply, the wound demonstrated a delayed incomplete healing over 8 months. In addition, X­ray imaging revealed a nonunion and a resulting screw fracture of the two distal locking screws. The indications for revision surgery to treat the fracture and change the implant were fulfilled. In the same procedure, the residual cutaneous defects were closed. Given the previously complication-prone course and a difficult local blood flow situation, the choice of reconstruction procedures was limited. A bridge flap of the medial lower leg was performed in an interdisciplinary approach. The lifting defect was covered with split-thickness skin. In this way, the wound was finally adequately covered after 1 year.

Nuclear Magnetic Resonance Treatment Induces ßNGF Release from Schwann Cells and Enhances the Neurite Growth of Dorsal Root Ganglion Neurons In Vitro.

Peripheral nerve regeneration depends on close interaction between neurons and Schwann cells (SCs). After nerve injury, SCs produce growth factors and cytokines that are crucial for axon re-growth. Previous studies revealed the supernatant of SCs exposed to nuclear magnetic resonance therapy (NMRT) treatment to increase survival and neurite formation of rat dorsal root ganglion (DRG) neurons in vitro. The aim of this study was to identify factors involved in transferring the observed NMRT-induced effects to SCs and consequently to DRG neurons. Conditioned media of NMRT-treated (CM NMRT) and untreated SCs (CM CTRL) were tested by beta-nerve growth factor (ßNGF) ELISA and multiplex cytokine panels to profile secreted factors. The expression of nociceptive transient receptor potential vanilloid 1 (TRPV1) channels was assessed and the intracellular calcium response in DRG neurons to high-potassium solution, capsaicin or adenosine triphosphate was measured mimicking noxious stimuli. NMRT induced the secretion of ßNGF and pro-regenerative-signaling factors. Blocking antibody experiments confirmed ßNGF as the main factor responsible for neurotrophic/neuritogenic effects of CM NMRT. The TRPV1 expression or sensitivity to specific stimuli was not altered, whereas the viability of cultured DRG neurons was increased. Positive effects of CM NMRT supernatant on DRG neurons are primarily mediated by increased ßNGF levels.

Skin Bank Establishment in Treatment of Severe Burn Injuries: Overview and Experience with Skin Allografts at the Vienna Burn Center.

Depending on their extent, burn injuries require different treatment strategies. In cases of severe large-area trauma, the availability of vital skin for autografting is limited. Donor skin allografts are a well-established but rarely standardized option for temporary wound coverage. Ten patients were eligible for inclusion in this retrospective study. Overall, 202 donor skin grafts obtained from the in-house skin bank were applied in the Department of Plastic and Reconstructive and Aesthetic Surgery, Medical University of Vienna. Between 2017 and 2022, we analysed the results in patient treatment, the selection of skin donors, tissue procurement, tissue processing and storage of allografts, as well as the condition and morphology of the allografts before application. The average Abbreviated Burn Severity Index (ABSI) was 8.5 (range, 5-12), and the mean affected total body surface area (TBSA) was 46.1% (range, 20-80%). In total, allograft application was performed 14 times. In two cases, a total of eight allografts were removed due to local infection, accounting for 3.96% of skin grafts. Six patients survived the acute phase of treatment. Scanning electron microscope images and histology showed no signs of scaffold decomposition and intact tissue layers of the allografts. The skin banking program and the application of skin allografts at the Vienna Burn Center can be considered successful. In severe burn injuries, skin allografts provide time by serving as sufficient wound coverage after early necrosectomy. Having an in-house skin banking program at a dedicated burn centre is particularly advantageous since issues of availability and distribution can be minimized. Skin allografts provide a reliable treatment option in patients with extensive burn injuries.

Systematic Comparison of Commercial Hydrogels Revealed That a Synergy of Laminin and Strain-Stiffening Promotes Directed Migration of Neural Cells.

Hydrogels have shown potential in replacing damaged nerve tissue, but the ideal hydrogel is yet to be found. In this study, various commercially available hydrogels were compared. Schwann cells, fibroblasts, and dorsal root ganglia neurons were seeded on the hydrogels, and their morphology, viability, proliferation, and migration were examined. Additionally, detailed analyses of the gels' rheological properties and topography were conducted. Our results demonstrate vast differences on cell elongation and directed migration on the hydrogels. Laminin was identified as the driver behind cell elongation and in combination with a porous, fibrous, and strain-stiffening matrix structure responsible for oriented cell motility. This study improves our understanding of cell-matrix interactions and thereby facilitates tailored fabrication of hydrogels in the future.