scholarly journals The Need for Inducing Tolerance in Vascularized Composite Allotransplantation

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Kadiyala V. Ravindra ◽  
Hong Xu ◽  
Larry D. Bozulic ◽  
David D. Song ◽  
Suzanne T. Ildstad

Successful hand and face transplantation in the last decade has firmly established the field of vascularized composite allotransplantation (VCA). The experience in VCA has thus far been very similar to solid organ transplantation in terms of the morbidity associated with long-term immunosuppression. The unique immunological features of VCA such as split tolerance and resistance to chronic rejection are being investigated. Simultaneously there has been laboratory work studying tolerogenic protocols in animal VCA models. In order to optimize VCA outcomes, translational studies are needed to develop less toxic immunosuppression and possibly achieve donor-specific tolerance. This article reviews the immunology, animal models, mixed chimerism & tolerance induction in VCA and the direction of future research to enable better understanding and wider application of VCA.

2019 ◽  
Vol 116 (51) ◽  
pp. 25784-25789 ◽  
Author(s):  
James D. Fisher ◽  
Stephen C. Balmert ◽  
Wensheng Zhang ◽  
Riccardo Schweizer ◽  
Jonas T. Schnider ◽  
...  

For individuals who sustain devastating composite tissue loss, vascularized composite allotransplantation (VCA; e.g., hand and face transplantation) has the potential to restore appearance and function of the damaged tissues. As with solid organ transplantation, however, rejection must be controlled by multidrug systemic immunosuppression with substantial side effects. As an alternative therapeutic approach inspired by natural mechanisms the body uses to control inflammation, we developed a system to enrich regulatory T cells (Tregs) in an allograft. Microparticles were engineered to sustainably release TGF-β1, IL-2, and rapamycin, to induce Treg differentiation from naïve T cells. In a rat hindlimb VCA model, local administration of this Treg-inducing system, referred to as TRI-MP, prolonged allograft survival indefinitely without long-term systemic immunosuppression. TRI-MP treatment reduced expression of inflammatory mediators and enhanced expression of Treg-associated cytokines in allograft tissue. TRI-MP also enriched Treg and reduced inflammatory Th1 populations in allograft draining lymph nodes. This local immunotherapy imparted systemic donor-specific tolerance in otherwise immunocompetent rats, as evidenced by acceptance of secondary skin grafts from the hindlimb donor strain and rejection of skin grafts from a third-party donor strain. Ultimately, this therapeutic approach may reduce, or even eliminate, the need for systemic immunosuppression in VCA or solid organ transplantation.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
David A. Leonard ◽  
Duncan A. McGrouther ◽  
Josef M. Kurtz ◽  
Curtis L. Cetrulo

Since the start of the clinical vascularized composite allotransplantation (VCA) era over a decade ago this field has witnessed significant developments in both basic and translational research. Transplant tolerance, defined as rejection-free acceptance of transplanted organs or tissues without long-term immunosuppression, holds the potential to revolutionize the field of VCA by removing the need for life-long immunosuppression. While tolerance of organ and vascularized composite transplants may be induced in small animal models by a variety of protocols, only mixed-chimerism-based protocols have successfully bridged the gap to preclinical study and to clinical trial in solid organ transplantation to date. In this paper we review the mixed-chimerism approach to tolerance induction, with specific reference to the field of VCA transplantation, and provide an overview of some novel cellular therapies as potential adjuvants to mixed chimerism in the development of tolerance induction protocols for clinical vascularized composite allotransplantation.


KIDNEYS ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 130-136
Author(s):  
Yusuf Ercin Sonmez

A transplant between two people who are not genetically identical is called an allotransplant and the process is called allotransplantation. Donor organs and tissues can be from people who are living, or people who have died because of a significant brain injury or lack of circulation. Allotransplantation can create a rejection process where the immune system of the recipient attacks the foreign donor organ or tissue and destroys it. The recipient may need to take immunosuppressive medication for the rest of their life to reduce the risk of rejection of the donated organ. In general, deliberately induced immunosuppression is performed to prevent the body from rejecting an organ transplant. The adverse effects associated with these agents and the risks of long-term immunosuppression present a number of challenges for the clinician. Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that have the capacity to elicit an immune response in a given organism.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Wei-Chao Huang ◽  
Jeng-Yee Lin ◽  
Christopher Glenn Wallace ◽  
Fu-Chan Wei ◽  
Shuen-Kuei Liao

Although vascularized composite allografts (VCAs) have been performed clinically for a variety of indications, potential complications from long-term immunosuppression and graft-versus-host disease remain important barriers to widespread applications. Recently it has been demonstrated that VCAs incorporating a vascularized long bone in a rat model provide concurrent vascularized bone marrow transplantation that, itself, functions to establish hematopoietic chimerism and donor-specific tolerance following non-myeloablative conditioning of recipients. Advances such as this, which aim to improve the safety profile of tolerance induction, will help usher in an era of wider clinical VCA application for nonlife-saving reconstructions.


2021 ◽  
Vol 12 ◽  
Author(s):  
Abraham J. Matar ◽  
Rebecca L. Crepeau ◽  
Gerhard S. Mundinger ◽  
Curtis L. Cetrulo ◽  
Radbeh Torabi

Over the past twenty years, significant technical strides have been made in the area of vascularized composite tissue allotransplantation (VCA). As in solid organ transplantation, the allogeneic immune response remains a significant barrier to long-term VCA survival and function. Strategies to overcome acute and chronic rejection, minimize immunosuppression and prolong VCA survival have important clinical implications. Historically, large animals have provided a valuable model for testing the clinical translatability of immune modulating approaches in transplantation, including tolerance induction, co-stimulation blockade, cellular therapies, and ex vivo perfusion. Recently, significant advancements have been made in these arenas utilizing large animal VCA models. In this comprehensive review, we highlight recent immune strategies undertaken to improve VCA outcomes with a focus on relevant preclinical large animal models.


Author(s):  
A. V. Shabunin ◽  
S. P. Loginov ◽  
P. A. Drozdov ◽  
I. V. Nesterenko ◽  
D. A. Makeev ◽  
...  

Rationale. To date, liver transplantation is the most effective method of treating end-stage liver failure, and therefore this treatment has become widespread throughout the world. However, due to the improvement in the quality of transplant care and an increase in the long-term survival of patients, the development of concomitant pathology, which often requires medical treatment, is inevitably associated with a higher life expectancy of liver transplant recipients. Thus, in patients who underwent liver transplantation, there is. a significant increase in the incidence of dyslipidemia. However, a long-term immunosuppressive therapy in organ transplant patients can adversely modify the effect of the prescribed drugs, which requires careful monitoring and consideration of drug interactions.Purpose. Using a clinical example to demonstrate the importance of taking drug interactions into account in the treatment of patients after organ transplantation receiving immunosuppressive drugs.Material and methods. In the presented clinical case, a patient after orthotopic liver transplantation performed in 2005 underwent a staged treatment of cicatricial stricture of choledochal anastomosis in the S.P. Botkin City Clinical Hospital. During the following hospitalization, the patient complained of minor muscle pain when walking. At doctor's visit 3 weeks before hospitalization, a local physician prescribed therapy with atorvastatin 10 mg per day due to an increase in blood plasma cholesterol levels. The patient underwent removal of the self-expanding nitinol stent. During the follow-up examination, the patient had no evidence of an impaired bile outflow, however, muscle pain and weakness progressively increased, the rate of diuresis decreased, and in the biochemical analysis of blood there was an abrupt increase in the concentration of creatinine, aspartate aminotransferase, alanine aminotransferase. Atorvastatin was canceled, a diagnosis of acute non-traumatic rhabdomyolysis was established, treatment with hemodialysis and plasma exchange was started on 03/05/2020. The last session of renal replacement therapy was 03/30/20.Results. With the restoration of the diuresis rate, there was a spontaneous decrease in the level of creatinine to 170 μmol/L. The patient was discharged with satisfactory renal and hepatic function. The pain syndrome completely resolved. Conclusion. Drug interactions between atorvastatin and cyclosporine have resulted in acute rhabdomyolysis with life-threatening consequences. This once again confirms the importance of taking drug interactions into account when managing patients after solid organ transplantation.


2021 ◽  
Vol 11 ◽  
Author(s):  
Manuel Alfredo Podestà ◽  
Giuseppe Remuzzi ◽  
Federica Casiraghi

Transplantation is the gold-standard treatment for the failure of several solid organs, including the kidneys, liver, heart, lung and small bowel. The use of tailored immunosuppressive agents has improved graft and patient survival remarkably in early post-transplant stages, but long-term outcomes are frequently unsatisfactory due to the development of chronic graft rejection, which ultimately leads to transplant failure. Moreover, prolonged immunosuppression entails severe side effects that severely impact patient survival and quality of life. The achievement of tolerance, i.e., stable graft function without the need for immunosuppression, is considered the Holy Grail of the field of solid organ transplantation. However, spontaneous tolerance in solid allograft recipients is a rare and unpredictable event. Several strategies that include peri-transplant administration of non-hematopoietic immunomodulatory cells can safely and effectively induce tolerance in pre-clinical models of solid organ transplantation. Mesenchymal stromal cells (MSC), non-hematopoietic cells that can be obtained from several adult and fetal tissues, are among the most promising candidates. In this review, we will focus on current pre-clinical evidence of the immunomodulatory effect of MSC in solid organ transplantation, and discuss the available evidence of their safety and efficacy in clinical trials.


2019 ◽  
Vol 160 (30) ◽  
pp. 1178-1183
Author(s):  
Ádám Varga ◽  
Károly Kalmár Nagy ◽  
Péter Szakály

Abstract: Tacrolimus is an important part of immunosuppressive therapy after solid organ transplantation. The therapeutic range of the drug from the calcineurin inhibitor group is narrow. Adjustment of the blood concentration can be very complicated but to be able to avoid the occurrence of side effects or ineffective immunosuppression it is inevitable. This article summarizes the properties of tacrolimus pharmacokinetics, pharmacogenetics and pharmacodynamics. We will focus on individual variations of cytochrome enzymes. In the following part, a new method for screening high risk patients will be introduced. We will present the publications of the determination of the concentration/dose (C/D) ratio. By determining the C/D ratio, researchers identify fast and slow metabolizing patient groups. Fast metabolizers require higher doses in general and the occurrence of complications is also more frequent in this group. Long-term results are lagging behind the slow metabolizing group. The long-term results of renal transplantation nowadays contribute to the postoperative period and the later years rather than the surgery itself. It includes the proper management of previous illnesses (e.g., hypertension, diabetes, endocrinological problems), detection of complications (e.g., infections, malignancies), and the precise regulation of immunosuppressive therapy. Orv Hetil. 2019; 160(30): 1178–1183.


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