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1.
Front Transplant ; 3: 1346667, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993750

RESUMEN

This report proposes a framework for evaluating the validity of informed consent and autonomy in face transplant candidates, taking into account the risk of depression and non-compliance. Traditional factors like decisional capacity, disclosure, comprehension, voluntariness, and agreement are insufficient for assessing valid informed consent in individuals whose self-worth relies on public perception, potentially leading to self-harm if societal worth is undermined. Reliance on self-esteem, rather than inherent personal value, poses risks of depression, poor treatment adherence, and deferential vulnerability. We suggest a qualitative analysis of self-worth, self-esteem, self-trust, and self-respect to better assess the autonomy of face transplant candidates in their decision-making process.

2.
Front Transplant ; 3: 1406626, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993746

RESUMEN

Vascularized Composite Allotransplantation (VCA) offers a unique option to restore form and function after limb loss or facial trauma that cannot be satisfactorily accomplished through traditional prosthetics or reconstructions. Establishing a successful Upper Extremity Transplantation (UET) program requires strong leadership and a structured surgical team, and extensive interdisciplinary collaboration. We conducted a qualitative study among 12 health care professionals and patients. Informed consent was obtained per protocol, and semi-structured interviews were conducted online and recorded. Participants reported their perceptions of factors that either favored or hindered a successful outcome, including functional status before and after surgery, preparation for transplant, shared decision-making, rehabilitation, and psychosocial support. Thematic analysis revealed that it is essential to establish a team comprising various disciplines well before performing VCA procedures. Defining a common goal and choosing a defined leader is a key factor in procedural success and requires open collaboration beyond what is typical. Primary described categories are interdisciplinary collaboration and skills of the VCA team, building and leading a VCA team, pre-transplant procedures, post-transplant course, and factors to consider when establishing a program. The basic roles of team science play an outsized role in establishing a VCA program. Transplantation medicine involves various overlapping scientific and medical categories requiring health professionals to consciously work together to establish complex vertical and horizontal communication webs between teams to obtain positive outcomes. In addition to medical considerations, patient-specific factors such as transparent communication, therapy plan establishment, plan adherence, and continual follow-up are significant factors to overall success.

3.
Front Transplant ; 3: 1421154, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993756

RESUMEN

For some patients who have lost the lower part of an arm, hand transplant offers the possibility of receiving a new limb with varying degrees of sensation and function. This procedure, Vascularized Composite Allotransplantation (VCA), is demanding for patients and their care community and comes with significant risks. As a high-stakes decision, patients interested in VCA are subject to extensive clinical evaluation and eligibility decision making. Patients and their care community must also decide if hand transplant (versus other approaches including rehabilitative therapies with or without prosthesis) is right for them. This decision making is often confusing and practically and emotionally fraught. It is complicated in four ways: by the numerous beneficial and harmful potential effects of hand transplant or other options, the number of people affected by VCA and the diverse or conflicting positions that they may hold, the practical demands and limitations of the patient's life situation, and the existential significance of limb loss and transplant for the patient's being. Patients need support in working through these treatment determining issues. Evaluation does not provide this support. Shared decision making (SDM) is a method of care that helps patients think, talk, and feel their way through to the right course of action for them. However, traditional models of SDM that focus on weighing possible beneficial and harmful effects of treatments are ill-equipped to tackle the heterogeneous issues of VCA. A recent model, Purposeful SDM extends the range of troubling issues that SDM can help support beyond opposing effects, to include conflicting positions, life situations, and existential being. In this paper we explore the pertinence of these issues in VCA, methods of SDM that each require of clinicians, the benefits of supporting patients with the breadth of issues in their unique problematic situations, implications for outcomes and practice, and extend the theory of the Purposeful SDM model itself based on the issues present in hand transplant decision making.

4.
Front Transplant ; 3: 1339898, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993757

RESUMEN

Vascularized composite allotransplantation (VCA) is an emerging field in transplant surgery. Despite overall positive outcomes, VCA confers risk for multiple complications related to the procedure and subsequent immunosuppression. Post-transplant lymphoproliferative disorder (PTLD) is a heterogeneous group of lymphoproliferative disorders occurring after solid organ and hematopoietic stem cell transplant. A patient with PTLD after bilateral upper extremity transplantation is presented as well as a review of all known cases of PTLD after VCA, with a focus on the unique epidemiology, presentation, and treatment in this population.

5.
J Adv Res ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38992424

RESUMEN

INTRODUCTION: Despite recent substantial progress in vascularized composite allotransplantation (VCA), such as face transplantations, short- and long-term allograft survival is severely limited by allograft rejection. The acute-phase response, directly after allogeneic transplantation, represents an immune-inflammatory reaction to ischemia/reperfusion and acts as an early initiator of graft rejection. Acute-phase reactants mediate this immune response via crosstalk with the mononuclear phagocyte system. OBJECTIVE: C-reactive protein (CRP), a well-known marker of inflammation, has pro-inflammatory properties and aggravates ischemia/reperfusion injury. Thus, we investigated how CRP impacts acute allograft rejection. METHODS: Based on clinical observations in facial VCAs, we applied a complex hindlimb transplantation model in rats to investigate whether CRP directly affects transplant rejection. We further analyzed subset-specific infiltration and tissue distribution of recipient-derived monocytes in the early phase of acute rejection and assessed their differential regulation by CRP using intravital imaging. RESULTS: We demonstrate that CRP accelerates allograft rejection and reduces allograft survival via selectively activating non-classical monocytes. The therapeutic stabilization of CRP abrogates this activating effect on monocytes, consequently attenuating acute allograft rejection. Intravital imaging of graft-infiltrating, recipient-derived monocytes during the early phase of acute rejection confirmed their differential regulation by CRP and their crucial role in driving the early stage of graft rejection. CONCLUSION: Differential activation of recipient-derived monocytes by CRP aggravates innate immune response and accelerates clinical allograft rejection Thus, therapeutic targeting of CRP represents a novel promising strategy for preventing acute allograft rejection and potentially reducing chronic allograft rejection.

6.
Front Transplant ; 3: 1433414, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38993751

RESUMEN

[This corrects the article DOI: 10.3389/frtra.2024.1346667.].

7.
J Tissue Eng ; 15: 20417314241254508, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38826796

RESUMEN

Vascularized composite allotransplantation (VCA), which can effectively improve quality of life, is a promising therapy for repair and reconstruction after face or body trauma. However, intractable issues are associated with VCA, such as the inevitable multiple immunogenicities of different tissues that cause severe rejection, the limited protocols available for clinical application, and the shortage of donor sources. The existing regimens used to extend the survival of patients receiving VCAs and suppress rejection are generally the lifelong application of immunosuppressive drugs, which have side effects. Consequently, studies aiming at tissue engineering methods for VCA have become a topic. In this review, we summarize the emerging therapeutic strategies for tissue engineering aimed to prolong the survival time of VCA grafts, delay the rejection and promote prevascularization and tissue regeneration to provide new ideas for future research on VCA treatment.

8.
J Surg Res ; 300: 389-401, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38851085

RESUMEN

INTRODUCTION: Vascularized composite allotransplantation (VCA) is the transplantation of multiple tissue types as a solution for devastating injuries. Despite the highly encouraging functional outcomes of VCA, the consequences of long-term immunosuppression remain the main obstacle in its application. In this review, we provide researchers and surgeons with a summary of the latest advances in the field of cell-based therapies for VCA tolerance. METHODS: Four electronic databases were searched: PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature , and Web of Science. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis as the basis of our organization. RESULTS: Hematopoietic stem cells prolonged VCA survival. A combination of immature dendritic cells and tacrolimus was superior to tacrolimus alone. T cell Ig domain and mucin domain modified mature dendritic cells increased VCA tolerance. Bone marrow-derived mesenchymal stem cells prolonged survival of VCAs. A combination of adipose-derived mesenchymal stem cells, cytotoxic T-lymphocyte antigen 4 immunoglobulin, and antilymphocyte serum significantly improved VCA tolerance. Ex-vivo allotransplant perfusion with recipient's bone marrow-derived mesenchymal stem cells increased VCA survival. Recipient's adipose-derived mesenchymal stem cells and systemic immunosuppression prolonged VCA survival more than any of those agents alone. Additionally, a combination of peripheral blood mononuclear cells shortly incubated in mitomycin and cyclosporine significantly improved VCA survival. Finally, a combination of donor recipient chimeric cells, anti-αß-T cell receptor (TCR), and cyclosporine significantly prolonged VCA tolerance. CONCLUSIONS: Evidence from animal studies shows that cell-based therapies can prolong survival of VCAs. However, there remain many obstacles for these therapies, and they require rigorous clinical research given the rarity of the subjects and the complexity of the therapies. The major limitations of cell-based therapies include the need for conditioning with immunosuppressive drugs and radiation, causing significant toxicity. Safety concerns also persist as most research is on animal models. While completely replacing traditional immunosuppression with cell-based methods is unlikely soon, these therapies could reduce the need for high doses of immunosuppressants and improve VCA tolerance.


Asunto(s)
Alotrasplante Compuesto Vascularizado , Humanos , Alotrasplante Compuesto Vascularizado/métodos , Animales , Supervivencia de Injerto/inmunología , Supervivencia de Injerto/efectos de los fármacos , Tolerancia al Trasplante , Inmunosupresores/uso terapéutico , Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Rechazo de Injerto/inmunología , Rechazo de Injerto/prevención & control , Trasplante de Células Madre Mesenquimatosas/métodos
9.
J Hand Microsurg ; 16(1): 100011, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38854368

RESUMEN

Background: Microsurgical techniques have revolutionized the field of reconstructive surgery and are the mainstay for complex soft tissue reconstruction. However, their limitations have promoted the development of viable alternatives. This article seeks to explore technologies that have the potential of revolutionizing microsurgical reconstruction as it is currently known, reflect on current and future vascularized composite allotransplantation (VCA) practices, as well as describe the basic science within emerging technologies and their potential translational applications. Methods: A literature review was performed of the technologies that may represent the future of microsurgery: vascularized tissue engineering (VCA) and flap-specific tissue engineering. Results: VCA has shown great promise and has already been employed in the clinical setting (especially in face and limb transplantation). Immunosuppression, logistics, cost, and regulatory pathways remain barriers to overcome to make it freely available. Vascularized and flap-specific tissue engineering remain a laboratory reality but have the potential to supersede VCA. The capability of creating an off-the-shelf free flap matching the required tissue, size, and shape is a significant advantage. However, these technologies are still at the early stage and require significant advancement before they can be translated into the clinical setting. Conclusion: VCA, vascularized tissue engineering, and flap-specific bioengineering represent possible avenues for the evolution of current microsurgical techniques. The next decade will elucidate which of these three strategies will evolve into a tangible translational option and hopefully bring a paradigm shift of reconstructive surgery.

10.
Front Immunol ; 15: 1390163, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38840906

RESUMEN

Background: Vascularized composite allotransplantation (VCA) offers the potential for a biological, functional reconstruction in individuals with limb loss or facial disfigurement. Yet, it faces substantial challenges due to heightened immune rejection rates compared to solid organ transplants. A deep understanding of the genetic and immunological drivers of VCA rejection is essential to improve VCA outcomes. Methods: Heterotopic porcine hindlimb VCA models were established and followed until reaching the endpoint. Skin and muscle samples were obtained from VCA transplant recipient pigs for histological assessments and RNA sequencing analysis. The rejection groups included recipients with moderate pathological rejection, treated locally with tacrolimus encapsulated in triglycerol-monostearate gel (TGMS-TAC), as well as recipients with severe end-stage rejection presenting evident necrosis. Healthy donor tissue served as controls. Bioinformatics analysis, immunofluorescence, and electron microscopy were utilized to examine gene expression patterns and the expression of immune response markers. Results: Our comprehensive analyses encompassed differentially expressed genes, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathways, spanning various composite tissues including skin and muscle, in comparison to the healthy control group. The analysis revealed a consistency and reproducibility in alignment with the pathological rejection grading. Genes and pathways associated with innate immunity, notably pattern recognition receptors (PRRs), damage-associated molecular patterns (DAMPs), and antigen processing and presentation pathways, exhibited upregulation in the VCA rejection groups compared to the healthy controls. Our investigation identified significant shifts in gene expression related to cytokines, chemokines, complement pathways, and diverse immune cell types, with CD8 T cells and macrophages notably enriched in the VCA rejection tissues. Mechanisms of cell death, such as apoptosis, necroptosis and ferroptosis were observed and coexisted in rejected tissues. Conclusion: Our study provides insights into the genetic profile of tissue rejection in the porcine VCA model. We comprehensively analyze the molecular landscape of immune rejection mechanisms, from innate immunity activation to critical stages such as antigen recognition, cytotoxic rejection, and cell death. This research advances our understanding of graft rejection mechanisms and offers potential for improving diagnostic and therapeutic strategies to enhance the long-term success of VCA.


Asunto(s)
Perfilación de la Expresión Génica , Rechazo de Injerto , Transcriptoma , Alotrasplante Compuesto Vascularizado , Animales , Rechazo de Injerto/inmunología , Rechazo de Injerto/genética , Porcinos , Modelos Animales de Enfermedad , Miembro Posterior
11.
Cureus ; 16(5): e59746, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38841001

RESUMEN

Introduction To date, upper extremity transplantation (UET) is the most frequently performed vascularized composite allotransplantation (VCA). Perceptions regarding upper extremity donation among Americans, particularly in veterans and service members (VSMs), are largely unknown. Materials and methods We administered a one-time survey to United States (US)-resident Amazon Mechanical Turk (MTurk) workers aged ≥18 years. Descriptive statistics were used to summarize study data; frequencies and percentages were calculated for categorical variables analyzed by Fischer's exact test and using a two-tailed test assessing the statistical significance of p<0.05. Results A total of 860 respondents completed the study survey. Among these, 529 (61.5%) reported willingness to donate an upper extremity, 152 (17.7%) were undecided, and 179 (20.8%) were unwilling. A significantly higher proportion of those willing to donate were female (66.7%, p=0.009), non-Hispanic (63.9%, p=0.000), White (64.0%, p=0.004), non-religious (71.3%, p=0.001), not a VSM (62.8%, p=0.000), or non-amputees (62.9%, p=0.000). Conclusions Our survey found that being female, non-Hispanic, White, non-religious, non-VSM, or non-amputee was significantly associated with donation willingness. These findings may help guide VCA programs, organ procurement organizations, and researchers in efforts to develop targeted educational materials to broaden the public's knowledge and awareness of VCA donation to further benefit all patients in need of or desiring transplantation.

12.
Cureus ; 16(5): e60941, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38910738

RESUMEN

Introduction As of 2008, the United States had 41,000 people living with upper extremity amputation. This number is projected to reach 300,000 by 2050. Human upper extremity transplantation (HUET) may become a more common treatment option with the potential to significantly improve the quality of life for certain amputees. Awareness and opinions regarding HUET among Americans, particularly in Veterans/Service Members (VSM) affiliates, are largely unknown. Materials and methods We administered a survey on Amazon Mechanical Turk (MTurk) workers. Eligible participants were US citizens aged ≥18 years; MTurk worker selection targeted workers who self-reported being a VSM. We used descriptive statistics to summarize study findings and Fisher's exact and Wilcoxon's rank-sum tests for between-group comparisons. Results The survey was completed by 764 individuals, 604 (79.1%) of whom reported being aware of HUET. Among those familiar versus unfamiliar, a significantly higher proportion were aged ≤35 years (n=385, 64.0% vs. n=86, 53.7%; p=0.017), employed (n=523, 86.6% vs. n=114, 71.3%; p<0.001), and aware of their religion's stance on organ/tissue donation (n=341, 54.5% vs. n=62, 38.8%; p<0.001). Amputees and/or respondents related to an amputee were more likely to be aware of HUET than individuals who were amputation naive (n=211, 90.6% vs. n=393, 74.0%, respectively; p<0.001), as were individuals with a personal or familial military affiliation (n=286, 85.4% with vs. n=318, 74.1% with no affiliation; p<0.001). The most reported HUET information sources were digital media (n=157, 31.2%) and internet (n=137, 27.2%). Conclusions Our survey of MTurk workers found greater awareness of HUET among individuals with a VSM or amputee connection. Our additional findings that the internet and academic sources, such as journals or reputable medical publications, were respondents' preferred sources of HUET information emphasize the importance of vascularized composite allotransplantation (VCA) centers' involvement in creating accurate and accessible content to help educate the public about this treatment.

13.
Front Immunol ; 15: 1387945, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38887281

RESUMEN

Introduction: The standard treatment for preventing rejection in vascularized composite allotransplantation (VCA) currently relies on systemic immunosuppression, which exposes the host to well-known side effects. Locally administered immunosuppression strategies have shown promising results to bypass this hurdle. Nevertheless, their progress has been slow, partially attributed to a limited understanding of the essential mechanisms underlying graft rejection. Recent discoveries highlight the crucial involvement of innate immune components, such as neutrophil extracellular traps (NETs), in organ transplantation. Here we aimed to prolong graft survival through a tacrolimus-based drug delivery system and to understand the role of NETs in VCA graft rejection. Methods: To prevent off-target toxicity and promote graft survival, we tested a locally administered tacrolimus-loaded on-demand drug delivery system (TGMS-TAC) in a multiple MHC-mismatched porcine VCA model. Off-target toxicity was assessed in tissue and blood. Graft rejection was evaluated macroscopically while the complement system, T cells, neutrophils and NETs were analyzed in graft tissues by immunofluorescence and/or western blot. Plasmatic levels of inflammatory cytokines were measured using a Luminex magnetic-bead porcine panel, and NETs were measured in plasma and tissue using DNA-MPO ELISA. Lastly, to evaluate the effect of tacrolimus on NET formation, NETs were induced in-vitro in porcine and human peripheral neutrophils following incubation with tacrolimus. Results: Repeated intra-graft administrations of TGMS-TAC minimized systemic toxicity and prolonged graft survival. Nevertheless, signs of rejection were observed at endpoint. Systemically, there were no increases in cytokine levels, complement anaphylatoxins, T-cell subpopulations, or neutrophils during rejection. Yet, tissue analysis showed local infiltration of T cells and neutrophils, together with neutrophil extracellular traps (NETs) in rejected grafts. Interestingly, intra-graft administration of tacrolimus contributed to a reduction in both T-cellular infiltration and NETs. In fact, in-vitro NETosis assessment showed a 62-84% reduction in NETs after stimulated neutrophils were treated with tacrolimus. Conclusion: Our data indicate that the proposed local delivery of immunosuppression avoids off-target toxicity while prolonging graft survival in a multiple MHC-mismatch VCA model. Furthermore, NETs are found to play a role in graft rejection and could therefore be a potential innovative therapeutic target.


Asunto(s)
Sistemas de Liberación de Medicamentos , Trampas Extracelulares , Rechazo de Injerto , Supervivencia de Injerto , Neutrófilos , Tacrolimus , Alotrasplante Compuesto Vascularizado , Trampas Extracelulares/inmunología , Trampas Extracelulares/efectos de los fármacos , Animales , Supervivencia de Injerto/efectos de los fármacos , Porcinos , Rechazo de Injerto/inmunología , Rechazo de Injerto/prevención & control , Tacrolimus/administración & dosificación , Neutrófilos/inmunología , Neutrófilos/efectos de los fármacos , Alotrasplante Compuesto Vascularizado/métodos , Inmunosupresores/administración & dosificación , Linfocitos T/inmunología , Humanos , Aloinjertos Compuestos/inmunología , Femenino
14.
Arch Plast Surg ; 51(3): 342-345, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38737844

RESUMEN

Vascularized Composite Tissue Allotransplantation (VCA) allows replacement of lost body parts from brain-dead donors. These surgeries are laborious, time-intensive, and require vast planning. With the advent of better immunosuppressants, VCA will increasingly play an important role in the reconstructive field. In this paper, the authors share their standard operating protocol created after much deliberation.

15.
Transpl Int ; 37: 12338, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38813393

RESUMEN

The current gold standard for preserving vascularized composite allografts (VCA) is 4°C static cold storage (SCS), albeit muscle vulnerability to ischemia can be described as early as after 2 h of SCS. Alternatively, machine perfusion (MP) is growing in the world of organ preservation. Herein, we investigated the outcomes of oxygenated acellular subnormothermic machine perfusion (SNMP) for 24-h VCA preservation before allotransplantation in a swine model. Six partial hindlimbs were procured on adult pigs and preserved ex vivo for 24 h with either SNMP (n = 3) or SCS (n = 3) before heterotopic allotransplantation. Recipient animals received immunosuppression and were followed up for 14 days. Clinical monitoring was carried out twice daily, and graft biopsies and blood samples were regularly collected. Two blinded pathologists assessed skin and muscle samples. Overall survival was higher in the SNMP group. Early euthanasia of 2 animals in the SCS group was linked to significant graft degeneration. Analyses of the grafts showed massive muscle degeneration in the SCS group and a normal aspect in the SNMP group 2 weeks after allotransplantation. Therefore, this 24-h SNMP protocol using a modified Steen solution generated better clinical and histological outcomes in allotransplantation when compared to time-matched SCS.


Asunto(s)
Supervivencia de Injerto , Preservación de Órganos , Perfusión , Alotrasplante Compuesto Vascularizado , Animales , Preservación de Órganos/métodos , Perfusión/métodos , Porcinos , Alotrasplante Compuesto Vascularizado/métodos , Miembro Posterior , Aloinjertos Compuestos , Modelos Animales , Trasplante Homólogo , Aloinjertos
16.
Antioxidants (Basel) ; 13(5)2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38790636

RESUMEN

Vascularized composite allografts (VCA) face ischemic challenges due to their limited availability. Reperfusion following ischemia triggers oxidative stress and immune reactions, and scavenger molecules could mitigate ischemia-reperfusion injuries and, therefore, immune rejection. We compared two scavengers in a myocutaneous flap VCA model. In total, 18 myocutaneous flap transplants were performed in Major histocompatibility complex (MHC)-defined miniature swine. In the MATCH group (n = 9), donors and recipients had minor antigen mismatch, while the animals were fully mismatched in the MISMATCH group (n = 9). Grafts were pretreated with saline, sodium iodide (NaI), or hydrogen sulfide (H2S), stored at 4 °C for 3 h, and then transplanted. Flaps were monitored until clinical rejection without immunosuppression. In the MATCH group, flap survival did not significantly differ between the saline and hydrogen sulfide treatments (p = 0.483) but was reduced with the sodium iodide treatment (p = 0.007). In the MISMATCH group, survival was similar between the saline and hydrogen sulfide treatments (p = 0.483) but decreased with the sodium iodide treatment (p = 0.007). Rhabdomyolysis markers showed lower but non-significant levels in the experimental subgroups for both the MATCH and MISMATCH animals. This study provides insightful data for the field of antioxidant-based approaches in VCA and transplantation.

17.
Bioengineering (Basel) ; 11(4)2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38671729

RESUMEN

Static cold storage (SCS), the current clinical gold standard for organ preservation, provides surgeons with a limited window of time between procurement and transplantation. In vascularized composite allotransplantation (VCA), this time limitation prevents many viable allografts from being designated to the best-matched recipients. Machine perfusion (MP) systems hold significant promise for extending and improving organ preservation. Most of the prior MP systems for VCA have been built and tested for large animal models. However, small animal models are beneficial for high-throughput biomolecular investigations. This study describes the design and development of a multiparametric bioreactor with a circuit customized to perfuse rat abdominal wall VCAs. To demonstrate its concept and functionality, this bioreactor system was employed in a small-scale demonstrative study in which biomolecular metrics pertaining to graft viability were evaluated non-invasively and in real time. We additionally report a low incidence of cell death from ischemic necrosis as well as minimal interstitial edema in machine perfused grafts. After up to 12 h of continuous perfusion, grafts were shown to survive transplantation and reperfusion, successfully integrating with recipient tissues and vasculature. Our multiparametric bioreactor system for rat abdominal wall VCA provides an advanced framework to test novel techniques to enhance normothermic and sub-normothermic VCA preservations in small animal models.

18.
Bioengineering (Basel) ; 11(4)2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38671744

RESUMEN

Reconstructive techniques to repair severe tissue defects include the use of autologous fasciocutaneous flaps, which may be limited due to donor site availability or lead to complications such as donor site morbidity. A number of synthetic or natural dermal substitutes are in use clinically, but none have the architectural complexity needed to reconstruct deep tissue defects. The perfusion decellularization of fasciocutaneous flaps is an emerging technique that yields a scaffold with the necessary composition and vascular microarchitecture and serves as an alternative to autologous flaps. In this study, we show the perfusion decellularization of porcine fasciocutaneous flaps using sodium dodecyl sulfate (SDS) at three different concentrations, and identify that 0.2% SDS results in a decellularized flap that is efficiently cleared of its cellular material at 86%, has maintained its collagen and glycosaminoglycan content, and preserved its microvasculature architecture. We further demonstrate that the decellularized graft has the porous structure and growth factors that would facilitate repopulation with cells. Finally, we show the biocompatibility of the decellularized flap using human dermal fibroblasts, with cells migrating as deep as 150 µm into the tissue over a 7-day culture period. Overall, our results demonstrate the promise of decellularized porcine flaps as an interesting alternative for reconstructing complex soft tissue defects, circumventing the limitations of autologous skin flaps.

19.
Front Immunol ; 15: 1372862, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38650942

RESUMEN

Balancing the immune response after solid organ transplantation (SOT) and vascularized composite allotransplantation (VCA) remains an ongoing clinical challenge. While immunosuppressants can effectively reduce acute rejection rates following transplant surgery, some patients still experience recurrent acute rejection episodes, which in turn may progress to chronic rejection. Furthermore, these immunosuppressive regimens are associated with an increased risk of malignancies and metabolic disorders. Despite significant advancements in the field, these IS related side effects persist as clinical hurdles, emphasizing the need for innovative therapeutic strategies to improve transplant survival and longevity. Cellular therapy, a novel therapeutic approach, has emerged as a potential pathway to promote immune tolerance while minimizing systemic side-effects of standard IS regiments. Various cell types, including chimeric antigen receptor T cells (CAR-T), mesenchymal stromal cells (MSCs), regulatory myeloid cells (RMCs) and regulatory T cells (Tregs), offer unique immunomodulatory properties that may help achieve improved outcomes in transplant patients. This review aims to elucidate the role of cellular therapies, particularly MSCs, T cells, Tregs, RMCs, macrophages, and dendritic cells in SOT and VCA. We explore the immunological features of each cell type, their capacity for immune regulation, and the prospective advantages and obstacles linked to their application in transplant patients. An in-depth outline of the current state of the technology may help SOT and VCA providers refine their perioperative treatment strategies while laying the foundation for further trials that investigate cellular therapeutics in transplantation surgery.


Asunto(s)
Trasplante de Órganos , Humanos , Trasplante de Órganos/efectos adversos , Animales , Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Rechazo de Injerto/inmunología , Rechazo de Injerto/prevención & control , Inmunomodulación
20.
Am J Bioeth ; 24(5): 59-73, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38181210

RESUMEN

As innovations in the field of vascular composite allotransplantation (VCA) progress, whole-eye transplantation (WET) is poised to transition from non-human mammalian models to living human recipients. Present treatment options for vision loss are generally considered suboptimal, and attendant concerns ranging from aesthetics and prosthesis maintenance to social stigma may be mitigated by WET. Potential benefits to WET recipients may also include partial vision restoration, psychosocial benefits related to identity and social integration, improvements in physical comfort and function, and reduced surgical risk associated with a biologic eye compared to a prosthesis. Perioperative and postoperative risks of WET are expected to be comparable to those of facial transplantation (FT), and may be similarly mitigated by immunosuppressive protocols, adequate psychosocial support, and a thorough selection process for both the recipient and donor. To minimize the risks associated with immunosuppressive medications, the first attempts in human recipients will likely be performed in conjunction with a FT. If first-in-human attempts at combined FT-WET prove successful and the biologic eye survives, this opens the door for further advancement in the field of vision restoration by means of a viable surgical option. This analysis integrates recent innovations in WET research with the existing discourse on the ethics of surgical innovation and offers preliminary guidance to VCA programs considering undertaking WET in human recipients.


Asunto(s)
Productos Biológicos , Alotrasplante Compuesto Vascularizado , Animales , Humanos , Alotrasplante Compuesto Vascularizado/métodos , Inmunosupresores , Mamíferos
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