Chimeric Cell Therapies as a Novel Approach for Duchenne Muscular Dystrophy (DMD) and Muscle Regeneration.

Chimerism-based strategies represent a pioneering concept which has led to groundbreaking advancements in regenerative medicine and transplantation. This new approach offers therapeutic potential for the treatment of various diseases, including inherited disorders. The ongoing studies on chimeric cells prompted the development of Dystrophin-Expressing Chimeric (DEC) cells which were introduced as a potential therapy for Duchenne Muscular Dystrophy (DMD). DMD is a genetic condition that leads to premature death in adolescent boys and remains incurable with current methods. DEC therapy, created via the fusion of human myoblasts derived from normal and DMD-affected donors, has proven to be safe and efficacious when tested in experimental models of DMD after systemic-intraosseous administration. These studies confirmed increased dystrophin expression, which correlated with functional and morphological improvements in DMD-affected muscles, including cardiac, respiratory, and skeletal muscles. Furthermore, the application of DEC therapy in a clinical study confirmed its long-term safety and efficacy in DMD patients. This review summarizes the development of chimeric cell technology tested in preclinical models and clinical studies, highlighting the potential of DEC therapy in muscle regeneration and repair, and introduces chimeric cell-based therapies as a promising, novel approach for muscle regeneration and the treatment of DMD and other neuromuscular disorders.

Transplantation of Donor-Recipient Chimeric Cells Restores Peripheral Blood Cell Populations and Increases Survival after Total Body Irradiation-Induced Injury in a Rat Experimental Model.

Current therapies for acute radiation syndrome (ARS) involve bone marrow transplantation (BMT), leading to graft-versus-host disease (GvHD). To address this challenge, we have developed a novel donor-recipient chimeric cell (DRCC) therapy to increase survival and prevent GvHD following total body irradiation (TBI)-induced hematopoietic injury without the need for immunosuppression. In this study, 20 Lewis rats were exposed to 7 Gy TBI to induce ARS, and we assessed the efficacy of various cellular therapies following systemic intraosseous administration. Twenty Lewis rats were randomly divided into four experimental groups (n = 5/group): saline control, allogeneic bone marrow transplantation (alloBMT), DRCC, and alloBMT + DRCC. DRCC were created by polyethylene glycol-mediated fusion of bone marrow cells from 24 ACI (RT1a) and 24 Lewis (RT11) rat donors. Fusion feasibility was confirmed by flow cytometry and confocal microscopy. The impact of different therapies on post-irradiation peripheral blood cell recovery was evaluated through complete blood count, while GvHD signs were monitored clinically and histopathologically. The chimeric state of DRCC was confirmed. Post-alloBMT mortality was 60%, whereas DRCC and alloBMT + DRCC therapies achieved 100% survival. DRCC therapy also led to the highest white blood cell counts and minimal GvHD changes in kidney and skin samples, in contrast to alloBMT treatment. In this study, transplantation of DRCC promoted the recovery of peripheral blood cell populations after TBI without the development of GVHD. This study introduces a novel and promising DRCC-based bridging therapy for treating ARS and extending survival without GvHD.

Donor-Recipient Chimeric Cell Transplantation as the Bridging Therapy for Mitigating Total Body Irradiation-Induced Injury.

In recent years, cell-based therapies have emerged as a promising approach for mitigating radiation-induced injury. Acute radiation syndrome (ARS) results from exposure to high doses of radiation over a short time period. This study aimed to compare the efficacy of donor-recipient chimeric cell (DRCC) therapy in mitigating ARS induced by a total body irradiation (TBI) dose of 10 gray (Gy). Thirty irradiated Lewis rats were employed as ARS models to assess the efficacy of systemic-intraosseous transplantation of different cellular therapies in five experimental groups (n = 6/group): saline control, isogenic bone marrow transplantation (isoBMT), allogeneic BMT (alloBMT), DRCC, and alloBMT+DRCC. DRCC were created by polyethylene glycol-mediated fusion of bone marrow cells from 24 ACI (RT1a) and 24 Lewis (RT11) rat donors. The creation of DRCC and chimeric state was confirmed by flow cytometry (FC) and confocal microscopy (CM). Recovery of blood parameters was evaluated through complete blood count analysis. Graft-versus-host disease (GvHD) signs were assessed clinically and histopathologically using kidney, skin, and small intestine biopsies. FC and CM confirmed the fusion feasibility and the chimeric state of DRCC. A 100% mortality rate was observed in the saline control group, whereas a 100% survival was recorded following DRCC transplantation, correlating with significant recovery of peripheral blood parameters. In addition, no clinical or histopathological signs of GvHD were observed after DRCC and alloBMT+DRCC transplantation. These findings confirm efficacy of DRCC in mitigating GvHD, promoting hematopoietic recovery, and increasing animal survival following TBI-induced ARS. Moreover, tolerogenic and immunomodulatory properties of DRCC therapy support its feasibility for clinical applications. Therefore, this study introduces DRCC as an innovative bridging therapy for alleviating the acute effects of TBI, with broad implications for stem cell research and regenerative medicine.

Efficacy of Engraftment and Safety of Human Umbilical Di-Chimeric Cell (HUDC) Therapy after Systemic Intraosseous Administration in an Experimental Model.

Cell-based therapies hold promise for novel therapeutic strategies in regenerative medicine. We previously characterized in vitro human umbilical di-chimeric cells (HUDCs) created via the ex vivo fusion of human umbilical cord blood (UCB) cells derived from two unrelated donors. In this in vivo study, we assessed HUDC safety and biodistribution in the NOD SCID mouse model at 90 days following the systemic intraosseous administration of HUDCs. Twelve NOD SCID mice (n = 6/group) received intraosseous injection of donor UCB cells (3.0 × 106) in Group 1, or HUDCs (3.0 × 106) in Group 2, without immunosuppression. Flow cytometry assessed hematopoietic cell surface markers in peripheral blood and the presence of HLA-ABC class I antigens in lymphoid and non-lymphoid organs. HUDC safety was assessed by weekly evaluations, magnetic resonance imaging (MRI), and at autopsy for tumorigenicity. At 90 days after intraosseous cell administration, the comparable expression of HLA-ABC class I antigens in selected organs was found in UCB control and HUDC therapy groups. MRI and autopsy confirmed safety by no signs of tumor growth. This study confirmed HUDC biodistribution to selected lymphoid organs following intraosseous administration, without immunosuppression. These data introduce HUDCs as a novel promising approach for immunomodulation in transplantation.

Assessment of Hematopoietic Response to Total Body Irradiation in a Rat Experimental Model.

BACKGROUND: Exposure to high doses of total body irradiation (TBI) may lead to the development of acute radiation syndrome (ARS). This study was conducted to establish an experimental rat model of TBI to assess the impact of different doses of TBI on survival and the kinetics of changes within the hematopoietic system in ARS. MATERIALS AND METHODS: In this study, 132 Lewis rats irradiated with a 5Gy or 7Gy dose served as experimental models to induce ARS and to evaluate the hematopoietic response of the bone marrow (BM) compartment. Animals were divided into 22 experimental groups (n = 6/group): groups 1-11 irradiated with 5Gy dose and groups 12-22 irradiated with 7Gy dose. The effects of TBI on the hematopoietic response were assessed at 2, 4, 6, 8 hours and 5, 10, 20, 30, 40, 60 and 90 days following TBI. Signs of ARS were evaluated by analyzing blood samples through complete blood count in addition to the clinical assessment. RESULTS: Groups irradiated with 5Gy TBI showed 100% survival, whereas after 7Gy dose, 1.6% mortality rate was observed. Assessment of the complete blood count revealed that lymphocytes were the first to be affected, regardless of the dose used, whereas an "abortive rise" of granulocytes was noted for both TBI doses. None of the animals exhibited signs of severe anemia or thrombocytopenia. All animals irradiated with 5Gy dose regained initial values for all blood cell subpopulations by the end of observation period. Body weight loss was reported to be dose-dependent and was more pronounced in the 7Gy groups. However, at the study end point at 90 days, all animals regained or exceeded the initial weight values. CONCLUSIONS: We have successfully established a rat experimental model of TBI. This study revealed a comparable hematopoietic response to the sublethal or potentially lethal doses of ionizing radiation. The experimental rat model of TBI may be used to assess different therapeutic approaches including BM-based cell therapies for long-term reconstitution of the hematopoietic and BM compartments allowing for comprehensive analysis of both the hematological and clinical symptoms associated with ARS.

Biodistribution and Safety of Human Multi-Chimeric Cells After Systemic Intraosseous and Intravenous Administration in the Experimental Mouse Model.

Cellular therapies provide promising options for inducing tolerance in transplantation of solid organs, bone marrow, and vascularized composite allografts. However, novel tolerance-inducing protocols remain limited, despite extensive research. We previously introduced and characterized a human multi-chimeric cell (HMCC) line, created through ex vivo fusion of human umbilical cord blood (UCB) cells derived from three unrelated donors. In this study, we assessed in vivo biodistribution and safety of HMCCs in the NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ NOD scid gamma (NSG) mouse model. Twenty-four NSG mice were randomly assigned to four groups (n = 6/group) and received intraosseous (IO.) or intravenous (IV.) injections of 0.6 × 106 donor UCB cells or fused HMCC: Group 1-UCB (IO.), Group 2-UCB (IV.), Group 3-HMCC (IO.), and Group 4-HMCC (IV.). Hematopoietic phenotype maintenance and presence of human leukocyte antigens (HLA), class I antigens, in the selected lymphoid and nonlymphoid organs were assessed by flow cytometry. Weekly evaluation and magnetic resonance imaging (MRI) assessed HMCC safety. Comparative analysis of delivery routes revealed significant differences in HLA class I percentages for IO.: 1.83% ± 0.79%, versus IV. delivery: 0.04% ± 0.01%, P < 0.01, and hematopoietic stem cell marker percentages of CD3 (IO.: 1.41% ± 0.04%, vs. IV.: 0.07% ± 0.01%, P < 0.05) and CD4 (IO.: 2.74% ± 0.31%, vs. IV.: 0.59% ± 0.11%, P < 0.01). Biodistribution analysis after IO. delivery confirmed HMCC presence in lymphoid organs and negligible presence in nonlymphoid organs, except for lung (IO.: 0.19% ± 0.06%, vs. IV.: 6.33% ± 0.56%, P < 0.0001). No evidence of tumorigenesis was observed by MRI at 90 days following IO. and IV. administration of HMCC. This study confirmed biodistribution and safety of HMCC therapy in the NSG mouse model, both following IO. and IV. administration. However, IO. delivery route confirmed higher efficacy of engraftment and safety profile, introducing HMCCs as a novel cell-based therapeutic approach with promising clinical applications in solid organ, bone marrow, and vascularized composite allotransplantation transplantation.

Hand and wrist - what the hand surgeon wants to know from the radiologist.

Hand surgeons, as unique specialists, appreciate the complexity of the anatomy of the hand. A hand is not merely a group of anatomic structures but a separate organ that works by feeling, sending information to the brain, and enabling a variety of movements, from precise skills to firm tasks. Acute and chronic problems interfere with complicated hand function and potentially influence work or daily life activities for a long time. Thus, the surgeon's role is to propose appropriate treatment with predictable results. This paper attempts to specify the preoperative considerations and their influence on the choice of surgical procedure and the assessment of results potentially influencing further treatment. We have divided the manuscript by anatomical structures, which is a natural surgical assessment and planning approach. The most common problems were highlighted to introduce the method of decision-making and surgical solutions.

Amelioration of Morphological Pathology in Cardiac, Respiratory, and Skeletal Muscles Following Intraosseous Administration of Human Dystrophin Expressing Chimeric (DEC) Cells in Duchenne Muscular Dystrophy Model.

Duchenne Muscular Dystrophy (DMD) is a lethal disease caused by mutation in the dystrophin gene. Currently there is no cure for DMD. We introduced a novel human Dystrophin Expressing Chimeric (DEC) cell therapy of myoblast origin and confirmed the safety and efficacy of DEC in the mdx mouse models of DMD. In this study, we assessed histological and morphological changes in the cardiac, diaphragm, and gastrocnemius muscles of the mdx/scid mice after the transplantation of human DEC therapy via the systemic-intraosseous route. The efficacy of different DEC doses was evaluated at 90 days (0.5 × 106 and 1 × 106 DEC cells) and 180 days (1 × 106 and 5 × 106 DEC cells) after administration. The evaluation of Hematoxylin & Eosin (H&E)-stained sectional slices of cardiac, diaphragm, and gastrocnemius muscles included assessment of muscle fiber size by minimal Feret's diameter method using ImageJ software. The overall improvement in muscle morphology was observed in DMD-affected target muscles in both studies, as evidenced by a shift in fiber size distribution toward the wild type (WT) phenotype and by an increase in the mean Feret's diameter compared to the vehicle-injected controls. These findings confirm the long-term efficacy of human DEC therapy in the improvement of overall morphological pathology in the muscles affected by DMD and introduce DEC as a novel therapeutic approach for DMD patients.

Assessment of Motor Unit Potentials Duration as the Biomarker of DT-DEC01 Cell Therapy Efficacy in Duchenne Muscular Dystrophy Patients up to 12 Months After Systemic-Intraosseous Administration.

Duchenne muscular dystrophy (DMD) is a lethal X-linked disease caused by mutations in the dystrophin gene, leading to muscle degeneration and wasting. Electromyography (EMG) is an objective electrophysiological biomarker of muscle fiber function in muscular dystrophies. A novel, DT-DEC01 therapy, consisting of Dystrophin Expressing Chimeric (DEC) cells created by fusing allogeneic myoblasts from normal donors with autologous myoblasts from DMD-affected patients, was assessed for safety and preliminary efficacy in boys of age 6-15 years old (n = 3). Assessments included EMG testing of selected muscles of upper (deltoideus, biceps brachii) and lower (rectus femoris and gastrocnemius) extremities at the screening visit and at 3, 6, and 12 months following systemic-intraosseous administration of a single low dose of DT-DEC01 therapy (Bioethics Committee approval no. 46/2019). No immunosuppression was administered. Safety of DT-DEC01 was confirmed by the lack of therapy-related Adverse Events or Serious Adverse Events up to 22 months following DT-DEC01 administration. EMG of selected muscles of both, ambulatory and non-ambulatory patients confirmed preliminary efficacy of DT-DEC01 therapy by an increase in motor unit potentials (MUP) duration, amplitudes, and polyphasic MUPs at 12 months. This study confirmed EMG as a reliable and objective biomarker of functional assessment in DMD patients after intraosseous administration of the novel DT-DEC01 therapy.

Novel cell-based strategies for immunomodulation in vascularized composite allotransplantation.

PURPOSE OF REVIEW: Vascularized composite allotransplantation (VCA) has become a clinical reality in the past two decades. However, its routine clinical applications are limited by the risk of acute rejection, and the side effects of the lifelong immunosuppression. Therefore, there is a need for new protocols to induce tolerance and extend VCA survival. Cell- based therapies have emerged as an attractive strategy for tolerance induction in VCA. This manuscript reviews the current strategies and applications of cell-based therapies for tolerance induction in VCA. RECENT FINDINGS: Cellular therapies, including the application of bone marrow cells (BMC), mesenchymal stem cells (MSC), adipose stem cells, regulatory T cells (Treg) cells, dendritic cells and donor recipient chimeric cells (DRCC) show promising potential as a strategy to induce tolerance in VCA. Ongoing basic science research aims to provide insights into the mechanisms of action, homing, functional specialization and standardization of these cellular therapies. Additionally, translational preclinical and clinical studies are underway, showing encouraging outcomes. SUMMARY: Cellular therapies hold great potential and are supported by preclinical studies and clinical trials demonstrating safety and efficacy. However, further research is needed to develop novel cell-based immunosuppressive protocol for VCA.

Safety and Efficacy of DT-DEC01 Therapy in Duchenne Muscular Dystrophy Patients: A 12 - Month Follow-Up Study After Systemic Intraosseous Administration.

Duchenne Muscular Dystrophy (DMD) is a progressive and fatal muscle-wasting disease with no known cure. We previously reported the preliminary safety and efficacy up to six months after the administration of DT-DEC01, a novel Dystrophin Expressing Chimeric (DEC) cell therapy created by fusion of myoblasts of DMD patient and the normal donor. In this 12-month follow-up study, we report on the safety and functional outcomes of three DMD patients after the systemic intraosseous administration of DT-DEC01. The safety of DT-DEC01 was confirmed by the absence of Adverse Events (AE) and Severe Adverse Events (SAE) up to 21 months after intraosseous DT-DEC01 administration. The lack of presence of anti-HLA antibodies and Donors Specific Antibodies (DSA) further confirmed DT-DEC01 therapy safety. Functional assessments in ambulatory patients revealed improvements in 6-Minute Walk Test (6MWT) and timed functions of North Star Ambulatory Assessment (NSAA). Additionally, improvements in PUL2.0 test and grip strength correlated with increased Motor Unit Potentials (MUP) duration recorded by Electromyography (EMG) in both ambulatory and non-ambulatory patients. DT-DEC01 systemic effect was confirmed by improved cardiac and pulmonary parameters and daily activity recordings. This follow-up study confirmed the safety and preliminary efficacy of DT-DEC01 therapy in DMD-affected patients up to 12 months after intraosseous administration. DT-DEC01 introduces a novel concept of personalized myoblast-based cellular therapy that is irrespective of the mutation type, does not require immunosuppression or the use of viral vectors, and carries no risk of off target mutations. This establishes DT-DEC01 as a promising and universally effective treatment option for all DMD patients.

Novel Human Umbilical Di-Chimeric (HUDC) cell therapy for transplantation without life-long immunosuppression.

Background: Cell-based therapies are promising for tolerance induction in bone marrow (BM), solid organs, and vascularized composite allotransplantation (VCA). The toxicity of bone marrow transplantation (BMT) protocols precludes this approach from routine clinical applications. To address this problem, we developed a new therapy of Human Umbilical Di-Chimeric (HUDC) cells for tolerance induction in transplantation. This study established in vitro characterization of the created HUDC cells. Methods: We performed sixteen ex vivo polyethylene glycol (PEG)-mediated fusions of human umbilical cord blood (UCB) cells from two unrelated donors. Fusion feasibility was confirmed in vitro by flow cytometry (FC) and confocal microscopy (CM). The HUDC cells' genotype was assessed by lymphocytotoxicity test and short tandem repeat-polymerase chain reaction (STR-PCR) analysis, phenotype by FC, viability by LIVE/DEAD® assay, and apoptosis level by Annexin V staining. We used COMET assay to assess HUDC cells' genotoxicity after the fusion procedure. Clonogenic properties of HUDC cells were evaluated by colony forming unit (CFU) assay. Mixed lymphocyte reaction (MLR) assay assessed immunogenic and tolerogenic properties of HUDC cells. Results: We confirmed the creation of HUDC cells from two unrelated human donors of UCB cells by FC and CM. Human leukocyte antigen (HLA) class I and II typing, and STR-PCR analysis of HUDC cells confirmed the presence of alleles and loci from both unrelated UCB donors (donor chimerism: 49%±8.3%, n=4). FC confirmed the hematopoietic phenotype of HUDC cells. We confirmed high HUDC cells' viability (0.47% of dead cells) and a low apoptosis level of fused HUDC cells (15.9%) compared to positive control of PKH-stained UCB cells (20.4%) before fusion. COMET assay of HUDC cells revealed a lack of DNA damage. CFU assay confirmed clonogenic properties of HUDC cells, and MLR assay revealed a low immunogenicity of HUDC cells. Conclusions: This study confirmed creation of a novel HUDC cell line by ex vivo PEG-mediated fusion of UCB cells from two unrelated donors. The unique concept of creating a HUDC cell line, representing the genotype and phenotype of both, transplant donor and the recipient, introduces a promising approach for tolerance induction in BM, solid organs, and VCA transplantation.

Human Multi-Chimeric Cell (HMCC) Therapy as a Novel Approach for Tolerance Induction in Transplantation.

Cellular therapies are regarded as the most promising approach for inducing transplant tolerance without life-long immunosuppression in solid organ and vascularized composite allotransplantation (VCA). Currently, no therapies are achieving this goal. This study introduces a novel Human Multi-Chimeric Cell (HMCC) line created by fusion of umbilical cord blood (UCB) cells, from three unrelated donors as an alternative therapeutic approach to bone marrow transplantation and tolerance induction in solid organ and VCA transplants. We performed eighteen ex vivo polyethylene glycol mediated fusions of human UCB cells from three unrelated donors to create HMCC. Mononuclear cells labeled with PKH26, PKH67, and eFluor™ 670 fluorescent dyes were fused and sorted creating a new population of triple-labeled (PKH26/PKH67/eFluor™ 670) HMCC. The creation of HMCC from three unrelated human UCB donors was confirmed by flow cytometry and confocal microscopy. Genotyping analyses determined the tri-chimeric state of HMCC by presence of parent alleles and selected loci specific for each of three UCB donors. Phenotype characterization confirmed hematopoietic markers distribution, comparable to UCB donors. HMCC maintained viability and displayed a low apoptosis level. The COMET assay revealed absence of genotoxicity, confirming fusion safety. Colony forming units assay showed clonogenic properties of HMCC. This study confirmed the feasibility of HMCC creation from three unrelated human UCB donors and characterized tri-chimeric state, hematopoietic phenotype, viability, safety, and clonogenic properties of HMCC. The created HMCC line, representing genotype characteristics of three unrelated human UCB donors, introduces a novel therapeutic approach for bone marrow, solid organ, and VCA transplants.

A Brief Review of Duchenne Muscular Dystrophy Treatment Options, with an Emphasis on Two Novel Strategies.

Despite the full cloning of the Dystrophin cDNA 35 years ago, no effective treatment exists for the Duchenne Muscular Dystrophy (DMD) patients who have a mutation in this gene. Many treatment options have been considered, investigated preclinically and some clinically, but none have circumvented all barriers and effectively treated the disease without burdening the patients with severe side-effects. However, currently, many novel therapies are in the pipelines of research labs and pharmaceutical companies and many of these have progressed to clinical trials. A brief review of these promising therapies is presented, followed by a description of two novel technologies that when utilized together effectively treat the disease in the mdx mouse model. One novel technology is to generate chimeric cells from the patient's own cells and a normal donor. The other technology is to systemically transplant these cells into the femur via the intraosseous route.

Dystrophin Expressing Chimeric (DEC) Cell Therapy for Duchenne Muscular Dystrophy: A First-in-Human Study with Minimum 6 Months Follow-up.

Duchenne Muscular Dystrophy (DMD) is a X-linked progressive lethal muscle wasting disease for which there is no cure. We present first-in-human study assessing safety and efficacy of novel Dystrophin Expressing Chimeric (DEC) cell therapy created by fusion of patient myoblasts with myoblasts of normal donor origin. We report here on safety and functional outcomes of the first 3 DMD patients. No study related adverse events (AE) and no serious adverse events (SAE) were observed up to 14 months after systemic-intraosseous administration of DEC01. Ambulatory patients showed improvements in functional tests (6-Minute Walk Test (6MWT), North Star Ambulatory Assessment (NSAA)) and both, ambulatory and non-ambulatory in PUL, strength and fatigue resistance which correlated with improvement of Electromyography (EMG) parameters. DEC01 therapy does not require immunosuppression, involves no risks of off target mutations, is not dependent upon the causative mutation and is therefore a universal therapy that does not use viral vectors and therefore can be readministered, if needed. This study was approved by the Bioethics Committee (approval No. 46/2019). Mechanism of action of the Dystrophin Expressing Chimeric Cell (DEC) cells created via ex vivo fusion of human myoblast from normal and DMD-affected donors. Following systemic-intraosseous administration, DEC engraft and fuse with the myoblasts of DMD patients, deliver dystrophin and improve muscle strength and function. (Created with BioRender.com).

Assessment of Human Epineural Conduit of Different Size Diameters on Efficacy of Nerve Regeneration and Functional Outcomes.

BACKGROUND: Different types of nerve conduits are used to bridge peripheral nerve gaps when a tension-free repair is unattainable. To best support nerve regeneration, naturally occurring conduits have been tested. Since allografts offer an unlimited source of epineurium, we have developed human epineural conduit (hEC) as a novel technology to bridge nerve gaps. Considering acellular properties, and lack of immunogenic response, epineurium-derived conduits represent an attractive material, when compared with nerve allografts that require systemic immunosuppression. In this study, we introduce the hEC as a novel naturally occurring material applied for repair of nerve gaps after trauma. METHODS: We tested the application of hEC created from human sciatic nerve in the restoration of 20 mm sciatic nerve defects in the nude rat model. Four experimental groups were studied: group 1: no repair control (n = 6), group 2: autograft control (n = 6), group 3: matched diameter hEC (n = 6), and group 4: large diameter hEC (n = 6). Functional tests of toe-spread and pin prick were performed at 1, 3, 6, 9, 12 weeks after repair. At 12 weeks, nerve samples were collected for immunostaining of Laminin B, S-100, glial fibrillary acidic protein (GFAP), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), von Willebrand factor, and histomorphometric analysis of myelin thickness, axonal density, fiber diameter, and percentage of the myelinated nerve fibers. Muscle samples were gathered for gastrocnemius muscle index (GMI) and muscle fiber area ratio measurements. RESULTS: Best functional recovery, as well as GMI, was revealed for the autograft group, and was comparable to the matched hEC group. Significant differences were revealed between matched and large hEC groups in expression of S100 (p = 0.0423), NGF (p = 0.269), VEGF (p = 0.0003) as well as in percentage of myelinated fibers (p < 0.001) and axonal density (p = 0.0003). CONCLUSION: We established the feasibility of hEC creation. The innovative method introduces an alternative technique to autograft repair of nerve defects.

Maxillary and Mandibular Healing After Facial Allotransplantation.

INTRODUCTION: Facial transplantation has emerged as a viable option in treating devastating facial injuries.Despite the high healing rate of Le Fort III and bilateral sagittal split osteotomies (BSSO) in nontransplant patients, few studies have reported assessment of maxillary and mandibular healing in face transplant patients compared with nontransplant patients. The aim of this study was to examine differences in bone healing in our patients. PATIENTS AND METHODS: A retrospective chart review was conducted of facial allotransplantation patients at the Cleveland Clinic from December 2008 to inception. Demographics such as age, date of birth, and sex were recorded. Additional variables included procedures, revisions, reoperations, medications, and bone stability and healing. Computed tomography (CT) images assessed the alignment of skeletal components, bony union quality, and stability of fixation. RESULTS: Three patients were included: 2 had Le Fort III segment transplantation, and 1 had transplantation of both a Le Fort III segment and mandibular BSSO. The Le Fort III segment in all patients exhibited mobility and fibrous union at the Le Fort III osteotomy on CT. In contrast, the BSSO healed uneventfully after transplantation and revision surgery, with bony union confirmed by both CT and histology of the fixation area between the donor and recipient mandible bilaterally. No patients with midfacial fibrous union required revision of the nonunion as they were clinically asymptomatic. CONCLUSION: Le Fort osteotomy demonstrates inferior healing in facial transplantation compared with the nontransplant population. In contrast, the successful healing in the mandible is likely owing to the high density of rich cancellous bone.

Youngest Composite Full-Face Transplant: A Model for Vascularized Composite Allograft in Younger Populations.

BACKGROUND: The field of face transplantation continues to evolve, with more complex defects being addressed, and, at the same time, increased outcome expectations. Given our unique long-term experience in this field, we consented one of the youngest patients to undergo a full-face transplant. METHODS: An 18-year-old woman presented with complete destruction of her central face and craniofacial structures. She had coexisting major injuries, including pituitary gland, visual axis, and motor control. After extensive rehabilitation and reconstruction techniques, the patient underwent face transplant on May 4, 2017, at the age of 21 years. RESULTS: The total operative time for the recipient was 26 hours. There were no major perioperative complications. Since transplant, the patient has undergone 3 revision surgeries. She is near completely independent from a daily life activity standpoint. She has had 1 episode of rejection above grade II that was successfully treated with a short-term increased in immunosuppression. CONCLUSIONS: Contrary to data in solid organ transplantation where youth is associated with increased risk of rejection, our current algorithm in immunosuppression, combined with this patient's compliance, has led to only 1 rejection episode beyond grade II. This successful transplant can serve as a model for future vascularized composite transplants in younger populations.