The Effects of Growth Hormone on Nerve Regeneration and Alloimmunity in Vascularized Composite Allotransplantation.

BACKGROUND: Poor outcomes in functional recovery following upper extremity transplantation are largely due to denervation-induced muscle atrophy that occurs during the prolonged period of nerve regeneration. Growth hormone (GH) has well-established trophic effects on neurons, myocytes, and Schwann cells and represents a promising therapeutic approach to address this challenge. This study sought to confirm the positive effects of GH treatment on nerve regeneration and functional recovery and to evaluate the effects of GH treatment on the immune response in the setting of vascularized composite allotransplantation. METHODS: Rats underwent orthotopic forelimb transplantation across a full MHC-mismatch and received either porcine-derived growth hormone or no treatment (n=18 per group). Functional recovery was measured using electrically-stimulated grip strength testing. Animals were monitored for clinical and subclinical signs of rejection. RESULTS: Neuromuscular junction reinnervation and grip strength were improved in GH-treated animals (p=0.005; p=0.08). No statistically significant differences were seen in muscle atrophy, degree of myelination, axon diameter, and axon counts between groups. The rates of clinical and histological rejection did not significantly differ among groups. CONCLUSIONS: Our findings alleviate concern for increased risk of transplant rejection during GH therapy and therefore support the translation of growth hormone as a therapeutic method to promote improved functional recovery in upper extremity transplantation.

Building an Academic Transgender Medicine Center of Excellence: The 5-Year Johns Hopkins Experience.

Gender-affirming care for transgender and gender diverse (TGD) individuals is a multidisciplinary endeavor that requires organized efforts of many specialized practitioners. TGD individuals experience many health care barriers, including the scarcity of multidisciplinary teams formed to coordinate and deliver complex care in an efficient and affirming way. The Johns Hopkins Center for Transgender Health was founded in 2017 with the mission of decreasing health disparities and improving the health of the TGD community. The authors present their experience building the center around a service line model in which patients have 1 point of contact, they are tracked throughout the care process, and the multidepartmental practitioners involved in their care are aligned. This model allowed for a patient-centered experience in which all involved disciplines were seamlessly integrated and the patient could navigate easily among them. With the structure and mission in place, the next challenge was to develop an infrastructure for culturally competent care. Through competency training and adjustment of systems-based logistics, measures were put in place to prevent traumatic experiences, such as misgendering, use of culturally inappropriate vocabulary, and use of incorrect names. Partnerships among colleagues in the fields of plastic surgery, urology, gynecology, otolaryngology, anesthesia, psychiatry/mental health, internal medicine, endocrinology, fertility, nursing, social work, speech therapy, and pediatrics/adolescent care were necessary to provide the appropriate breadth of services to care for TGD patients. Since its inception, the center has seen steady and continual growth, with more than 2,800 patients in its first 5 years. By sharing their experience in creating and developing a center of excellence, the authors hope to provide a blueprint for others to expand health care quality and access for TGD individuals.

The Efficacy of Schwann-Like Differentiated Muscle-Derived Stem Cells in Treating Rodent Upper Extremity Peripheral Nerve Injury.

BACKGROUND: There is a pressing need to identify alternative mesenchymal stem cell sources for Schwann cell cellular replacement therapy, to improve peripheral nerve regeneration. This study assessed the efficacy of Schwann cell-like cells (induced muscle-derived stem cells) differentiated from muscle-derived stem cells (MDSCs) in augmenting nerve regeneration and improving muscle function after nerve trauma. METHODS: The Schwann cell-like nature of induced MDSCs was characterized in vitro using immunofluorescence, flow cytometry, microarray, and reverse-transcription polymerase chain reaction. In vivo, four groups (n = 5 per group) of rats with median nerve injuries were examined: group 1 animals were treated with intraneural phosphate-buffered saline after cold and crush axonotmesis (negative control); group 2 animals were no-injury controls; group 3 animals were treated with intraneural green fluorescent protein-positive MDSCs; and group 4 animals were treated with green fluorescent protein-positive induced MDSCs. All animals underwent weekly upper extremity functional testing. Rats were euthanized 5 weeks after treatment. The median nerve and extrinsic finger flexors were harvested for nerve histomorphometry, myelination, muscle weight, and atrophy analyses. RESULTS: In vitro, induced MDSCs recapitulated native Schwann cell gene expression patterns and up-regulated pathways involved in neuronal growth/signaling. In vivo, green fluorescent protein-positive induced MDSCs remained stably transformed 5 weeks after injection. Induced MDSC therapy decreased muscle atrophy after median nerve injury (p = 0.0143). Induced MDSC- and MDSC-treated animals demonstrated greater functional muscle recovery when compared to untreated controls (hand grip after induced MDSC treatment: group 1, 0.91 N; group 4, 3.38 N); p < 0.0001) at 5 weeks after treatment. This may demonstrate the potential beneficial effects of MDSC therapy, regardless of differentiation stage. CONCLUSION: Both MDSCs and induced MDSCs decrease denervation muscle atrophy and improve subsequent functional outcomes after upper extremity nerve trauma in rodents.

Reinventing Yourself Virtually: Fifth Annual Society of Asian Academic Surgeons Virtual Conference.

Virtual forms of communication have been integrated into academic surgery now more than ever. The COVID-19 pandemic accelerated its implementation in an effort to support social-distancing. Academic surgery is now learning valuable lessons from early experiences to optimally integrate this communication mode. The Society of Asian Academic Surgeons convened an expert panel during the society's fifth annual meeting that explores these lessons. Realms of virtual communication including meetings, networking, surgery department administration, social media, application processes, and advice for early or mid-career academic surgeons are explored. Virtual conferences pose a new challenge by removing the in-person component that is evident to be integral to networking, collaboration, and all aspects of academic socialization. Strategies such as creating virtual chat rooms, mentor-mentee virtual introductions, and deliberate interactions can enhance the experience. Virtual administrative meetings require special attention to preparation and strategies to insure engagement. Social media can be a valuable tool to integrate into academic careers but special attention needs to be made to utilize it deliberately and not to shy away from our individuality. The interview process can be enhanced when made virtual to give opportunities to those typically disadvantaged in the usual, in-person process.

The intragraft vascularized bone marrow component plays a critical role in tolerance induction after reconstructive transplantation.

The role of the vascularized bone marrow component as a continuous source of donor-derived hematopoietic stem cells that facilitate tolerance induction of vascularized composite allografts is not completely understood. In this study, vascularized composite tissue allograft transplantation outcomes between recipients receiving either conventional bone marrow transplantation (CBMT) or vascularized bone marrow (VBM) transplantation from Balb/c (H2d) to C57BL/6 (H2b) mice were compared. Either high- or low-dose CBMT (1.5 × 108 or 3 × 107 bone marrow cells, respectively) was applied. In addition, recipients were treated with costimulation blockade (1 mg anti-CD154 and 0.5 mg CTLA4Ig on postoperative days 0 and 2, respectively) and short-term rapamycin (3 mg/kg/day for the first posttransplant week and then every other day for another 3 weeks). Similar to high-dose conventional bone marrow transplantation, 5/6 animals in the vascularized bone marrow group demonstrated long-term allograft survival (>120 days). In contrast, significantly shorter median survival was noted in the low-dose CBMT group (~64 days). Consistently high chimerism levels were observed in the VBM transplantation group. Notably, low levels of circulating CD4+ and CD8+ T cells and a higher ratio of Treg to Teff cells were maintained in VBM transplantation and high-dose CBMT recipients (>30 days) but not in low-dose VBM transplant recipients. Donor-specific hyporesponsiveness was shown in tolerant recipients in vitro. Removal of the vascularized bone marrow component after secondary donor-specific skin transplantation did not affect either primary allograft or secondary skin graft survival.

Clinical Characteristics of 90 Macrodactyly Cases.

PURPOSE: Macrodactyly is a rare, nonhereditary congenital deformity. Digital enlargement in macrodactyly involves all tissue types and presents alone or as part of a congenital deformity syndromes. Macrodactyly treatment largely depends on surgeons' experience and knowledge. Because there is a paucity of large cohort studies of macrodactyly in the literature, our goal was to retrospectively analyze macrodactyly cases in order to define a better system for diagnosis, classification, and prognosis. METHODS: Medical records of 90 Chinese macrodactyly patients, including demographic characteristics, clinical presentations, anatomical distributions, x-rays, pathological findings, and treatments, were reviewed. Genetic analyses of 12 patients were also reviewed. RESULTS: Disease incidence was similar across sex and geographical regions. Multiple-digit involvement was 2.6 times more frequent than single-digit involvement. The index finger, middle finger, and thumb were most commonly involved. Two digits were affected more often than 3, with the affected digits adjacent in most cases. The affected digit was in the median nerve innervation distribution in 79% of cases and was accompanied by enlargement and fat infiltration of the median nerve. Seven cases had syndactyly. Ten of the 12 cases subjected to PIK3CA mutation analysis were positive. CONCLUSIONS: Macrodactyly represents a heterogeneous group of conditions, without significant sex or geographical predilection, which is usually present at birth. A high PIK3CA mutation-positive rate in affected tissues suggests a similar cellular mechanism for overgrowth in patients with various clinical presentations. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Trauma-induced Rejection in Vascularized Composite Allotransplantation.

: Vascularized composite allotransplantation (VCA) is a relatively new field in reconstructive medicine. Likely a result of the unique tissue composition of these allografts-including skin and often a bone marrow component-the immunology and rejection patterns do not always mimic those of the well-studied solid organ transplantations. While the number and type of VCAs performed is rapidly expanding, there is still much to be discovered and understood in the field. With more patients, new findings and patterns emerge and add to our understanding of VCA. Here, we present a case report of an upper extremity transplant recipient with trauma-induced rejection.

Poly(ε-Caprolactone) Nanofiber Wrap Improves Nerve Regeneration and Functional Outcomes after Delayed Nerve Repair.

BACKGROUND: The purpose of this study was to assess the efficacy of biodegradable, electrospun poly(ε-caprolactone) nanofiber nerve conduits in improving nerve regeneration. METHODS: The authors used a rat forelimb chronic denervation model to assess the effects of poly(ε-caprolactone) conduits on improving nerve regeneration and upper extremity function. Three groups of rats were examined: (1) negative-control animals (n = 5), which underwent 8 weeks of median nerve chronic denervation injury followed by repair with no conduit; (2) experimental animals (n = 5), which underwent 8 weeks of median nerve chronic denervation followed by repair and poly(ε-caprolactone) nerve conduit wrapping of the nerve coaptation site; and (3) positive-control animals (n = 5), which were naive controls. All animals underwent compound muscle action potential and functional testing. At 14 weeks after repair, the median nerve and flexor muscles were harvested for histologic analysis. RESULTS: Histomorphometric analysis of regenerating median nerves demonstrated augmented axonal regeneration in experimental versus negative control animals (total axon count, 1769 ± 672 versus 1072 ± 123.80; p = 0.0468). With regard to functional recovery, experimental and negative-control animals (1.67 ± 0.04 versus 0.97 ± 0.39; p = 0.036) had regained 34.9 percent and 25.4 percent, respectively, of baseline hand grip strength at 14 weeks after repair. Lastly, less collagen deposition at the nerve coaptation site of experimental animals was found when compared to control animals (p < 0.05). CONCLUSION: Biodegradable, poly(ε-caprolactone) nanofiber nerve conduits can improve nerve regeneration and subsequent physiologic extremity function in the setting of delayed nerve repair by decreasing the scar burden at nerve coaptation sites.

Prosthetic Rehabilitation and Vascularized Composite Allotransplantation following Upper Limb Loss.

BACKGROUND: Upper limb loss is a devastating condition with dramatic physical, psychological, financial, and social consequences. Improvements in the fields of prosthetics and vascularized composite allotransplantation have opened exciting new frontiers for treatment and rehabilitation following upper limb loss. Each modality offers a unique set of advantages and limitations with regard to the restoration of hand function following amputation. METHODS: Presented in this article is a discussion outlining the complex considerations and decisions encountered when determining patient appropriateness for either prosthetic rehabilitation or vascularized composite allotransplantation following upper limb loss. In this review, the authors examine how psychosocial factors, nature of injury, rehabilitation course, functional outcomes, and risks and benefits may affect overall patient selection for either rehabilitative approach. RESULTS: This review summarizes the current state of the literature. Advancements in both prosthetic and biological strategies demonstrate promise with regard to facilitating rehabilitation following upper limb loss. However, there remains a dearth of research directly comparing outcomes in prosthetic rehabilitation to that following upper extremity transplantation. CONCLUSIONS: Few studies have performed a direct comparison between patients undergoing vascularized composite allotransplantation and those undergoing prosthetic rehabilitation. Upper extremity transplantation and prosthetic reconstruction should not be viewed as competing options, but rather as two treatment modalities with different risk-to-benefit profiles and indications.

Muscle-derived stem cells: important players in peripheral nerve repair.

INTRODUCTION: Stem cell therapy for peripheral nerve repair is a rapidly evolving field in regenerative medicine. Although most studies to date have investigated stem cells originating from bone marrow or adipose, skeletal muscle has recently been recognized as an abundant and easily accessible source of stem cells. Muscle-derived stem cells (MDSCs) are a diverse population of multipotent cells with pronounced antioxidant and regenerative capacity. Areas covered: The current literature on the various roles MDSCs serve within the micro- and macro-environment of nerve injury. Furthermore, the exciting new research that is establishing MDSC-cellular therapy as an important therapeutic modality to improve peripheral nerve regeneration. Expert opinion: MDSCs are a promising therapeutic agent for the repair of peripheral nerves; MDSCs not only undergo gliogenesis and angiogenesis, but they also orchestrate larger pro-regenerative host responses. However, the isolation, transformation, and in-vivo behavior of MDSCs require further evaluation prior to clinical application.

The suppression effect of dendritic cells maturation by adipose-derived stem cells through TGF-ß1 related pathway.

BACKGROUND: Our previous studies demonstrated that adipose-derived stem cells (ASCs) could modulate regulatory T cells (Treg) and prolong hind-limb allotransplant survival in vitro and in vivo. Dendritic cells (DCs) play a pivotal role in innate and adaptive immunity. The aim of this study is to investigate the underlying mechanism of ASCs in modulating DC maturation. MATERIALS AND METHODS: ASCs were isolated from rodent adipose tissue, DCs were derived from the bone marrow, and CD4+ T cells were purified from splenocytes. DCs were co-cultured with ASCs to evaluate the suppressive effects of ASCs. CD4+ T-cells were co-cultured with DCs pre-treated with or without ASCs. The cell surface markers of DCs were analyzed by flow cytometry. T-cell proliferation was analyzed by the BrdU proliferation test. Tolerogenic cytokines and indoleamine 2,3-dioxygenase (IDO) expressions after different treatments were detected by quantitative real-time PCR, Western blotting, and ELISA analysis. RESULT: ASCs suppressed DC maturation as evidenced by low expressions of CD80, CD86, and MHC-II. Also, ASC-treated mature DCs showed higher levels of TGF-ß1, IL-10, and IDO expressions, as compared to that in matured DCs (mDCs) alone. ASC-treated mDCs co-cultured with CD4+ T cells revealed a significant higher percentage of Treg than mDC without treatment. The IDO level in ASC-treated mDCs and Treg induction effects were blocked by the ASCs pre-treated with TGF-ß1 siRNAs, but not IL-10 siRNAs. CONCLUSION: ASC-modulated DC maturation correlated with TGF-ß1 secretion, IDO expression, and Treg induction. ASCs could be used as a potential immunomodulatory strategy for clinical application in allotransplantation.

From Auto- to Allotransplantation: Immunomodulatory Protocol for Hand and Arm Transplantation.

AIM: To achieve a favorable risk-benefit balance for hand transplantation, an immunomodulatory protocol was developed in the laboratory and translated to clinical application. METHODS: Following donor bone marrow infusion into transplant recipients, hand and arm allografts have been maintained on low-dose tacrolimus monotherapy. RESULTS: Good-to-excellent functional recovery has been achieved in patients compliant with medication and therapy, thus restoring autonomous and productive lives. CONCLUSION: The risk-benefit balance can be tilted in favor of the hand transplant recipients by using an immunomodulatory protocol with minimum immunosuppression.

Treatment of Proximal Interphalangeal Joint Contracture.

Proximal interphalangeal joint (PIPJ) flexion contracture is a challenging and often frustrating problem. Treatment of PIPJ contracture begins with conservative measures. With good compliance and prolonged use, favorable results can be achieved using these modalities. For contractures that fail to respond to conservative treatment, surgical intervention can be considered. The affected structures that can be released during surgery include the accessory collateral ligaments, volar plate, checkrein ligaments, retinacular ligaments, and the flexor and extensor tendons. A stepwise approach to release is typically favored in which active motion is tested after each release to determine the need for subsequent releases.

Desensitization and Prevention of Antibody-Mediated Rejection in Vascularized Composite Allotransplantation by Syngeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: Candidates for vascularized composite allotransplantation (VCA) are frequently sensitized, putting them at risk for antibody-mediated rejection. Current desensitization strategies are imperfect and require a living-donor setting. Here we investigated the impact of sensitization on and the efficacy of a desensitization protocol utilizing syngeneic hematopoietic stem cell transplantation (HSCT) to prevent antibody-mediated rejection in VCA. METHODS: Skin transplants from Dark Agouti to Lewis rats were performed for sensitization. Orthotopic hind limb transplants from Dark Agouti donors were performed to sensitized and nonsensitized recipients, and the animals were treated with either daily tacrolimus or no immunosuppression. A desensitization protocol consisting of total body irradiation, fludarabine, and syngeneic HSCT was applied to sensitized animals. Graft rejection was monitored by clinical assessment and histological analysis. Serum levels of donor-specific antibodies (DSA IgG) were measured using flow cytometry. RESULTS: Sensitized recipients exhibited accelerated rejection by 5.5 ± 1.2 days without immunosuppression and 10.2 ± 3.6 days with daily tacrolimus compared with 8.7 ± 1.2 days and longer than 30 days in nonsensitized recipients, respectively. Serum levels of DSA IgG were markedly elevated (37.3 ± 3.34-fold from baseline) in sensitized recipients after VCA and correlated with histologic evidence of rejection and C4d deposition. Desensitization significantly reduced DSA compared with sensitized controls (2.6 ± 0.5-fold vs 6.0 ± 1.2-fold, P < 0.01) and along with daily tacrolimus led to improved VCA survival longer than 30 days without evidence of C4d deposition (n = 6). CONCLUSIONS: In summary, sensitization leads to accelerated rejection of VCA, and syngeneic HSCT combined with conventional immunosuppression effectively reduces DSA and improves allograft survival in sensitized rats.

The Ethics of Hand Transplantation: A Systematic Review.

PURPOSE: We conducted a systematic review to document ethical concerns regarding human upper extremity (UE) allotransplantation and how these concerns have changed over time. METHODS: We performed a systematic review of 5 databases to find manuscripts addressing ethical concerns related to UE allotransplantation. Inclusion criteria were papers that were on the topic of UE allotransplantation, and related ethical concerns, written in English. We extracted and categorized ethical themes under the 4 principles of bioethics: Autonomy, Beneficence, Nonmaleficence, and Justice. We assessed theme frequency by publication year using Joinpoint regression, analyzing temporal trends, and estimating annual percent change. RESULTS: We identified 474 citations; 49 articles were included in the final analysis. Publication years were 1998 to 2015 (mean, 3 publications/y; range, 0-7 publications/y). Nonmaleficence was most often addressed (46 of 49 papers; 94%) followed by autonomy (36 of 49; 74%), beneficence (35 of 49; 71%), and justice (31 of 49; 63%). Of the 14 most common themes, only "Need for More Research/Data" (nonmaleficence) demonstrated a significant increase from 1998 to 2002. CONCLUSIONS: Upper extremity transplantation is an appealing reconstructive option for patients and physicians. Its life-enhancing (vs life-saving) nature and requirement for long-term immunosuppression have generated much ethical debate. Availability of human data has influenced ethical concerns over time. Our results indicate that discussion of ethical issues in the literature increased following publication of UE transplants and outcomes as well as after meetings of national societies and policy decisions by regulatory agencies. CLINICAL RELEVANCE: Because UE transplantation is not a life-saving procedure, much ethical debate has accompanied its evolution. It is important for UE surgeons considering referring patients for evaluation to be aware of this discussion to fully educate patients and help them make informed treatment decisions.

The promise of organ and tissue preservation to transform medicine.

The ability to replace organs and tissues on demand could save or improve millions of lives each year globally and create public health benefits on par with curing cancer. Unmet needs for organ and tissue preservation place enormous logistical limitations on transplantation, regenerative medicine, drug discovery, and a variety of rapidly advancing areas spanning biomedicine. A growing coalition of researchers, clinicians, advocacy organizations, academic institutions, and other stakeholders has assembled to address the unmet need for preservation advances, outlining remaining challenges and identifying areas of underinvestment and untapped opportunities. Meanwhile, recent discoveries provide proofs of principle for breakthroughs in a family of research areas surrounding biopreservation. These developments indicate that a new paradigm, integrating multiple existing preservation approaches and new technologies that have flourished in the past 10 years, could transform preservation research. Capitalizing on these opportunities will require engagement across many research areas and stakeholder groups. A coordinated effort is needed to expedite preservation advances that can transform several areas of medicine and medical science.

Vascular Endothelial Growth Factor Induction of Muscle-Derived Stem Cells Enhances Vascular Phenotype While Preserving Myogenic Potential.

BACKGROUND: Previous work by our group and other laboratories have revealed that muscle-derived stem cells (MDSCs) may contain both myogenic and endothelial progenitors, making MDSCs a promising option for skeletal muscle regeneration. The purpose of this study was to investigate the impact of vascular endothelial growth factor (VEGF) induction on the vascular and myogenic potential of MDSCs. METHODS: Muscle-derived stem cells were isolated from 4- to 8-week-old C57BL/6J mice using a preplate technique and recombinant human VEGFa was used as the induction agent. Cellular proliferation and migration were assessed using serial imaging and wound healing assays, respectively. Myosin heavy chain staining was performed to assess MDSC myotube formation. Vascular potential of MDSCs was measured by expression of CD31 and in vitro capillary tube formation. RESULTS: Vascular endothelial growth factor stimulation led to a dose-dependent increase in MDSC proliferation (P < 0.05) and migration kinetics (P < 0.01). Control MDSCs had low levels of baseline expression of CD31, which was significantly upregulated by VEGF stimulation. Similarly, MDSCs demonstrated a basal capability for capillary tube formation, which was significantly increased after VEGF induction as evidenced by increased branches (5.91 ± 0.58 vs 9.23 ± 0.67, P < 0.01) and total tube length (11.73 ± 0.97 vs 18.62 ± 1.57 mm, P < 0.01). Additionally, the myogenic potential of MDSCs as measured by fusion index remained unchanged with increasing concentration of VEGF up to 250 ng/mL (P = 0.77). CONCLUSIONS: Vascular endothelial growth factor induction enhances MDSC proliferation, migration, and endothelial phenotypes without negatively impacting myogenic potential. These results suggest that VEGF stimulation may improve vascularization of MDSC-based strategies for skeletal muscle regeneration.