From Lab to Limb: Unraveling Translational Insights and Significance of Animal Models in Lower Extremity Transplantation.

The advancements in medicine throughout the twentieth century have been largely attributed to animal studies. The initial step in researching an animal disease is to establish a model closely resembling the clinical circumstances in humans. Consequently, an excellent animal model is essential for almost any experimental research.

Experimental Models in Penile Transplantation: Translational Insights and Relevance to Clinical Application.

Animal research is an essential contributor to the medical achievements of the last century. The first step of studying a disease in animals is the development of a model which is relevant to the clinical situation in humans. Thus, a good animal model is the sine qua non of the experimental research.

Ten-Year Follow-Up of Lower Limb Replantation: Objective Evaluation With Gait Analysis.

The decision-making process for lower limb replantation involves several critical factors, such as age, comorbidities, ischemia time, type of injury, and psychosocial considerations. Advances in microsurgical techniques have led to a greater focus on enhancing functionality through limb salvage. To improve functional outcomes, it is essential to gain a better understanding of the current challenges in reconstruction and address them in future cases.

A World Update of Progress in Lower Extremity Transplantation: What's Hot and What's Not.

The field of vascularized composite allotransplantation (VCA) is the new frontier of solid organ transplantation (SOT). VCA spans life-enhancing/life-changing procedures such as upper extremity, craniofacial (including eye), laryngeal, tracheal, abdominal wall, penis, and lower extremity transplants. VCAs such as uterus transplants are life giving unlike any other SOT.

Osteocutaneous Fibular Flap for Reconstruction of Composite Metacarpal Defects Due to Gunshot Wounds.

Background: Gunshot wounds of the hand are challenging, as these injuries include bones, tendons neurovascular structures, and soft tissue. The osteocutaneous fibula flap has shown to be an excellent option for treating the composite defects, including bone and soft tissue. In this study, reconstructions of gunshot injuries of the metacarpal bones with a fibular flap are presented.

A Reversibly Thermoresponsive, Theranostic Nanoemulgel for Tacrolimus Delivery to Activated Macrophages: Formulation and In Vitro Validation.

Despite long-term immunosuppression, organ transplant recipients face the risk of immune rejection and graft loss. Tacrolimus (TAC, FK506, Prograf) is an FDA-approved keystone immunosuppressant for preventing transplant rejection. However, it undergoes extensive first-pass metabolism and has a narrow therapeutic window, which leads to erratic bioavailability and toxicity.

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.

Functional Reconstruction of Arches of the Foot With Vascularized Fibula Flap.

The skeletal integrity of the foot is as important as the soft tissue coverage of the foot. In this article, we present reconstruction of arches of foot with free fibula flap. Three patients with composite foot defects underwent reconstruction a with vascularized fibula flap.

Composite tissue xenopreservation: Preliminary results of staged VCA in rat to mouse model.

Background: The time between procurement and transplantation of composite tissues, especially regarding the limited donor pool, is a challenge effecting the outcomes of the transplantation. Current preservation techniques mainly include either cold preservation with a solution or machine perfusion using blood or certain oxygen-carrying solutions. However, none enables preservation beyond 24 h.

Peripheral nerve repair is associated with augmented cross-tissue inflammation following vascularized composite allotransplantation.

Introduction: Vascularized composite allotransplantation (VCA), with nerve repair/coaptation (NR) and tacrolimus (TAC) immunosuppressive therapy, is used to repair devastating traumatic injuries but is often complicated by inflammation spanning multiple tissues. We identified the parallel upregulation of transcriptional pathways involving chemokine signaling, T-cell receptor signaling, Th17, Th1, and Th2 pathways in skin and nerve tissue in complete VCA rejection compared to baseline in 7 human hand transplants and defined increasing complexity of protein-level dynamic networks involving chemokine, Th1, and Th17 pathways as a function of rejection severity in 5 of these patients. We next hypothesized that neural mechanisms may regulate the complex spatiotemporal evolution of rejection-associated inflammation post-VCA.

Implantable Biomaterials for Peripheral Nerve Regeneration-Technology Trends and Translational Tribulations.

The use of autografted nerve in surgical repair of peripheral nerve injuries (PNI) is severely limited due to donor site morbidity and restricted tissue availability. As an alternative, synthetic nerve guidance channels (NGCs) are available on the market for surgical nerve repair, but they fail to promote nerve regeneration across larger critical gap nerve injuries. Therefore, such injuries remain unaddressed, result in poor healing outcomes and are a limiting factor in limb reconstruction and transplantation.

The effect of thymus transplantation on donor-specific chimerism in the rat model of composite osseomusculocutaneous sternum, ribs, thymus, pectoralis muscles, and skin allotransplantation.

Introduction: Research on tolerance has proven that development of donor-specific chimerism (DSC) may accompany tolerance induction in vascularized composite allotransplantation (VCA). In this study, we aimed to determine the effect of thymus transplantation on the induction of DSC in rat VCA model of osseomusculocutaneous sternum (OMCS) and osseomusculocutaneous sternum and thymus (OMCST) allotransplantation.

Materials And Methods: A total of 20 Lewis-Brown Norway and Lewis rats, 5-6 weeks old, weighting between 120 and 150 g, were used in the study.

Biocompatibility in regenerative nanomedicine.

Biocompatibility is a very common word that is used within biomaterial science and used for description of the interactions between the foreign material and the body. However, the meaning of biocompatibility as well as the mechanisms that collectively constitutes is still unclear. With the advance of nanotechnology, new concerns have been observed related to biocompatibility of these biomaterials.

Adipogenesis for soft tissue reconstruction.

Purpose Of Review: It has been increasingly common to use adipose tissue for regenerative and reconstructive purposes. Applications of autologous fat transfer and different stem cell therapies have significant limitations and adipose tissue engineering may have the potential to be an important strategy in the reconstruction of large tissue defects. A better understanding of adipogenesis will help to develop strategies to make adipose tissue more effective for repairing volumetric defects.

Demonstration of technical feasibility and viability of whole eye transplantation in a rodent model.

Introduction: Whole eye transplantation (WET) holds promise for vision restoration in devastating/disabling visual loss (congenital or traumatic) not amenable to surgical or neuroprosthetic treatment options. The eye includes multiple tissues with distinct embryonic lineage and differential antigenicity. Anatomically and immunologically, the eye is unique due to its avascular (cornea) and highly vascular (retina) components.

Late Correction of Traumatic Nasal Deformities: A Surgical Algorithm and Experience in 120 Patients.

Background: Traumatic nasal deformities have a wide spectrum of presentations, which further complicates their management and preoperative planning. Although many methods and algorithms have been proposed for management of specific posttraumatic nasal deformities, such as twisted, deviated, saddle, or short nose, these algorithms usually focus on a specific deformity in isolation from the remainder of the nose.

Objectives: The aim of this study is to present an algorithm for traumatic nasal deformities and to evaluate the functional and aesthetic outcomes of this new algorithm by a preoperative and postoperative quality-of-life questionnaire.

A New Composite Eyeball-Periorbital Transplantation Model in Humans: An Anatomical Study in Preparation for Eyeball Transplantation.

Background: Vascularized composite allotransplantation offers a new hope for restoration of orbital content and perhaps vision. The aim of this study was to introduce a new composite eyeball-periorbital transplantation model in fresh cadavers in preparation for composite eyeball allotransplantation in humans.

Methods: The composite eyeball-periorbital transplantation flap borders included the inferior border, outlined by the infraorbital rim; the medial border, created by the nasal dorsum; the lateral border, created by the lateral orbital rim; and the superior border, created by the superior part of the eyebrow.

The neurochemistry of peripheral nerve regeneration.

Peripheral nerve injuries (PNIs) can be most disabling, resulting in the loss of sensitivity, motor function and autonomic control in the involved anatomical segment. Although injured peripheral nerves are capable of regeneration, sub-optimal recovery of function is seen even with the best reconstruction. Distal axonal degeneration is an unavoidable consequence of PNI.

The effect of in vivo created vascularized neurotube on peripheric nerve regeneration.

Introduction: Creating vascularized nerve conduits for treatment of nerve gaps have been researched, however, these methods need microsurgical anastomosis thereby complicating the nerve repair process. Thus, the concept of vascularized nerve conduits has not popularized up till now. The aim of this study is to evaluate the effects of vascularized and non-vascularized biological conduits on peripheral nerve regeneration.

Native extracellular matrix/fibroin hydrogels for adipose tissue engineering with enhanced vascularization.

Adipose tissue engineering is a promising field for regeneration of soft tissue defects. However, vascularization is needed since nutrients and oxygen cannot reach cells in thick implants by diffusion. Obtaining a biocompatible scaffold with good mechanical properties is another problem.

Pre-expanded Thoracodorsal Artery Perforator Flap.

The size of the thoracodorsal artery perforator (TDAP) flap or pedicle, in general, may be found to be inadequate. Pre-expansion of the flap before harvest can be a solution to increase the size of the TDAP flap in such instances. The pre-expanded TDAP flap can be used to reconstruct large-sized defects with the advantage of primary closure of the donor site.

Effects of hPTPβ inhibitor on microcirculation of rat cremaster muscle flap following ischemia-reperfusion injury.

Introduction: Inhibition of protein tyrosine phosphatases (PTP) enhances endothelial receptor tyrosine kinases activation and may have beneficial effects on vessel growth and improve blood flow to ischemic tissue. The purpose of this study is to determine influence of hPTPß inhibitors on ischemia-reperfusion injury in muscle flap.

Materials And Methods: Following cremaster muscle dissection, 60 rats divided into 10 experimental groups (placebo and treatment groups following 0, 1, 2, 3, and 4 h of ischemia).