Viability Of Transplants Research Articles

Development and Validation in Porcine and Human Models of a Bioimpedance Spectroscopy System for the Objective Assessment of Kidney Graft Viability.

This work presents an innovative bioimpedance spectroscopy device, developed as a support tool for decision-making during the evaluation of kidney viability for renal transplantation. Given the increasing demand for organs and the need to optimize donation criteria, the precise and objective assessment of renal graft functionality has become crucial. The device, based on a modular design and adapted to the surgical environment, uses a novel Cole model with a frequency-dependent membrane capacitance, which improves measurement accuracy and repeatability compared to conventional models. Adapting the device for operating room usege involved overcoming significant challenges, such as the need for sterilization and a visual, tactile and acoustic user interface that facilitates device usability. Optimizing the sensing stage has minimized the influence of measurement artifacts, which is crucial for obtaining accurate and representative measurements of renal tissue bioelectrical properties. In addition, a rigorous electrode sterilization protocol was designed, ensuring asepsis during the procedure. The results of tests on porcine renal models demonstrated the device's ability to monitor pathophysiological changes associated with renal ischemia, with a notable improvement against measurement repeatability.

Best practices of heart transplantation in mice.

Best practices of heart transplantation in mice.

Vascular Microphysiological System for Investigating Endothelial Barrier Function During Organ Preservation and Reperfusion.

Endothelial cell damage after cold preservation and reperfusion injury causes deterioration of the endothelial barrier and ultimately results in edema, leading to transplant failure. Here, a vascular microphysiological system (MPS) is introduced as a testbed to investigate the combinational effect of thermal and fluid perturbations (i.e., wall shear stress) on human endothelial barrier function. Two methods of organ storage are compared: isochoric supercooling (ISC) preservation, which prevents ice formation at subzero temperatures; and, the standard clinical protocol of static cold storage (SCS) at 4 °C. Integrating electrical impedance measurements on chip allow real-time monitoring and quantification of barrier function during preservation and reperfusion protocols. Isochoric supercooling preservation enables longer periods of preservation with superior recovery of barrier function during reperfusion, and has lower metabolic activities compared to static cold storage. Genomic analysis reveals injury and recovery mechanisms at the molecular level for the different preservation and reperfusion conditions. The multifunctional vascular microphysiological system provides a physiologically relevant in vitro model recapitulating ischemia-reperfusion injury to the endothelium. The vascular MPS has potential for optimizing organ preservation protocols, ultimately improving organ transplant viability.

I-JAMM (II)-Therapeutic Apheresis Practices in Preconditioning of ABO-Incompatible Kidney and Liver Transplants in India.

ABO-incompatible transplantations are increasingly gaining relevance with advancements in therapeutic modalities, thus allowing patients to receive timely solid organ transplants. Therapeutic apheresis (TA) procedures remain instrumental as a preconditioning measure to enable such transplants. This survey was undertaken to find out current trends and practices of TA across major transplant centers in India. The survey was drafted by a working group of transfusion and transplant immunology specialists from six different centers in India. Data were obtained via the use of an online questionnaire. Results were categorized into eight categories: hospital information, range of titers for preconditioning, considerations prior to starting TA, TA procedure details, role of pharmacotherapy in TA, policy for reuse of columns, risk of rebound, and the role of transfusion medicine specialists. The survey highlighted the modalities as well as the methodologies of various TA procedures used across different major transplant centers in India. With the increase in ABO-incompatible kidney and liver transplants across the country, the role of transfusion medicine and transplant immunology specialists have become vital in preconditioning regimes enabling the viability and success of such transplants. This was a unique survey that provided us a snapshot of current trends and practices of TA in preconditioning of patients for ABO-incompatible transplants in India.

Large area kidney imaging for pre-transplant evaluation using real-time robotic optical coherence tomography

Optical coherence tomography (OCT) can be used to image microstructures of human kidneys. However, current OCT probes exhibit inadequate field-of-view, leading to potentially biased kidney assessment. Here we present a robotic OCT system where the probe is integrated to a robot manipulator, enabling wider area (covers an area of 106.39 mm by 37.70 mm) spatially-resolved imaging. Our system comprehensively scans the kidney surface at the optimal altitude with preoperative path planning and OCT image-based feedback control scheme. It further parameterizes and visualizes microstructures of large area. We verified the system positioning accuracy on a phantom as 0.0762 ± 0.0727 mm and showed the clinical feasibility by scanning ex vivo kidneys. The parameterization reveals vasculatures beneath the kidney surface. Quantification on the proximal convoluted tubule of a human kidney yields clinical-relevant information. The system promises to assess kidney viability for transplantation after collecting a vast amount of whole-organ parameterization and patient outcomes data.

Evaluation of Bacterial Viability for Fecal Microbiota Transplantation: Impact of Thawing Temperature and Storage Time.

Fecal Microbiota Transplantation (FMT) represents a promising therapeutic tool under study for several purposes and is currently applied to the treatment of recurrent Clostridioides difficile infection. However, since the use of fresh stool was affected by several issues linked to donor screening, the development of a frozen stool bank is a reliable option to standardize FMT procedures. Nevertheless, different environmental factors impact microbial viability. Herein, we report the effect of different thawing temperatures and storage conditions on bacterial suspensions in the FMT procedure. In total, 20 stool samples were divided into aliquots and tested across a combination of different storing periods (15, 30; 90 days) and thawing procedures (4 °C overnight, room temperature for 1 h; 37 °C for 5 min). Focusing on storage time, our data showed a significant reduction in viability for aerobic and anaerobic bacteria after thawing for 15 days, while no further reductions were observed until after 90 days. Instead, among the different thawing procedures, no significant differences were observed for aerobic bacteria, while for anaerobes, thawing at 37 °C for 5 min was more effective in preserving the bacterial viability. In conclusion, the frozen fecal microbiota remained viable for at least three months, with an excellent recovery rate in all three thawing conditions.

Artificial Intelligence in the Detection of Fatty Liver Disease

Background: The current gold standard for quantification of the fat content of the liver (i.e., nonalcoholic fatty liver disease, NAFLD) is the visual microscopic inspection of liver biopsies by pathologists. Percentage of macrosteatosis (%MaS), used in determining NAFLD diagnosis, is vital in determining the transplant suitability of a donor liver. A major limitation of this method is inevitable human error which causes interobserver variability and overestimation of %MaS which could cause a potential discard of donor livers. We hypothesize that artificial intelligence (AI) can assist pathologists in providing a more objective and accurate measure of %MaS. Methods: Our literature review identified HALO (image analysis) and U-Net (deep-learning) as AI programs currently available for high-accuracy %MaS calculation in liver biopsies. We compared the pathologist-reported %MaS from de-novo liver transplant (LT) biopsy samples taken 2h post-reperfusion to the %MaS calculated by HALO and/or U-Net (Fig. 1). 250 patients had undergone de novo LT at Indiana University between 2019-2020, and 211 of these patients had sufficient data (liver enzyme tests, biopsy results) to be included. Each biopsy sample was digitized into 5 random non-overlapping tiles at 20x magnification using a Leica microscope. Early allograft dysfunction (EAD) is defined by the presence of at least one of the following: (i) INR >1.6 on postoperative day (POD) 7, (ii) total bilirubin >10 mg/dL on POD7, or (iii) AST/ALT >2000 IU/L within the first 7 days following LT. Results: Our literature review identified that both HALO and U-Net estimated the %MaS in liver allograft biopsies significantly lower than pathologists' estimation (Fig.1). Of 211 included patients, 46 (21.8%) had EAD. In this ongoing project, we found U-Net to have a 97.3% training accuracy with eight epochs (2000 biopsy images each). Tiles from the first ten patients are being analyzed by HALO and/or U-Net to calculate an average %MaS for each patient. These calculations will be compared to the %MaS estimation made by pathologists. Conclusions: The rapidly evolving field of AI is emerging as a promising method in the quantification of the fat content of the liver with increased accuracy. AI will therefore help pathologists and transplant surgeons to determine liver transplant viability and better predict EAD in transplant patients.

A Cadaveric Study of the Deep and Superficial Dorsal Veins for Penile Transplant

It is crucial to know the lengths of the neurovasculature proximal to a penile allograft to allow for better viability of a penile transplant. We performed a cadaveric exploration focused on the deep and superficial dorsal veins as identified in a microsurgical dissection of the penis to help expand the anatomical knowledge for such a procedure. We examined 18 cadavers and measured the (1) vertical distance from the pubic symphysis to the point at which the superficial dorsal vein is no longer on the erectile tissue; (2) point at which the superficial dorsal vein is no longer on the erectile tissue to where its tributary meets the great saphenous vein; and (3) point at which the deep dorsal vein is no longer on the external erectile tissue to its contribution into the prostatic plexus near the prostate. Moreover, we noted the variations of the deep and superficial veins of the penis. We used IBM SPSS in all statistical analyses. The average length of the superficial dorsal vein when no longer on the external penis to its tributary was 84.9 ± 10.4 mm. The average length of the deep dorsal vein was 72.9 ± 6.43 mm. Three different drain patterns were observed for the superficial dorsal vein, whereas the deep dorsal vein was consistently midline. No statistically significant correlations were identified between cadaveric demographic data and lengths of venous structures. Further studies regarding the anatomy and dissection of penile allografts would be helpful. More research regarding donor and recipient anatomy and vasculature is needed to establish surgical guidelines.

Hypoxia-induced PD-L1 expression and modulation of muscle stem cell allograft rejection.

Stem cell therapy has shown immense promise in treating genetic disorders, particularly muscular diseases like Duchenne muscular dystrophy (DMD). This study investigates a novel method to enhance the viability of stem cell transplants in DMD by upregulating Programmed Death Ligand 1 (PD-L1) in muscle stem cells (MuSCs) through preconditioning with hypoxia and/or interferon-γ (IFN-γ) to mitigate T cell immune rejection. MuSCs were treated with 5% hypoxia for 72h and further treated with IFN-γ to enhance PD-L1 expression. Additionally, gain and loss experiments using a PD-L1 inhibitor (BMS-1) were conducted to investigate cellular expression profiles in vitro and cell transplantation outcomes in vivo. Our results showed significant upregulation of PD-L1 in MuSCs under hypoxia and IFN-γ conditions without affecting cellular proliferation and differentiation in vitro. In vivo, these preconditioned MuSCs led to decreased infiltration of CD4+ and CD8+ T cells in implanted limb muscles of mouse models. Blocking PD-L1 reduced graft survival in muscles treated with MuSCs. Conversely, increased PD-L1 expression and reduced T cell infiltration correlated with improved graft survival, as identified by pre-labeled LacZ + MuSCs following transplantation. This study provides evidence that hypoxia and IFN-γ preconditioning of MuSCs can significantly enhance the efficacy of cell therapy for DMD by mitigating immune rejection. Our strategic approach aimed to improve donor cell survival and function post-transplantation by modifying immune responses towards the donor cells.

Ex Vivo Working Porcine Heart Model.

Ex vivo working porcine heart models allow for the study of a heart's function and physiology outside the living organism. These models are particularly useful due to the anatomical and physiological similarities between porcine and human hearts, providing an experimental platform to investigate cardiac disease or assess donor heart viability for transplantation. This chapter presents an in-depth discussion of the model's components, including the perfusate, preload, and afterload. We explore the challenges of emulating cardiac afterload and present a historical perspective on afterload modeling, discussing various methodologies and their respective limitations. An actively controlled afterload device is introduced to enhance the model's ability to rapidly adjust pressure in the large arteries, thereby providing a more accurate and dynamic experimental model. Finally, we provide a comprehensive experimental protocol for the ex vivo working porcine heart model.

Estimating cardiac mechanical efficiency in a porcine ex situ working heart model

Estimating cardiac mechanical efficiency in a porcine ex situ working heart model

I-JAMM-(I): A survey providing an insight into the practices of isoagglutinin titration in ABO incompatible kidney and liver transplantation

I-JAMM-(I): A survey providing an insight into the practices of isoagglutinin titration in ABO incompatible kidney and liver transplantation

The role of efferocytosis and transplant rejection: Strategies in promoting transplantation tolerance using apoptotic cell therapy and/or synthetic particles.

Recently, efforts have been made to recognize the precise reason(s) for transplant failure and the process of rejection utilizing the molecular signature. Most transplant recipients do not appreciate the unknown length of survival of allogeneic grafts with the existing standard of care. Two noteworthy immunological pathways occur during allogeneic transplant rejection. A nonspecific innate immune response predominates in the early stages of the immune reaction, and allogeneic antigens initiate a donor-specific adaptive reaction. Though the adaptive response is the major cause of allograft rejection, earlier pro-inflammatory responses that are part of the innate immune response are also regarded as significant in graft loss. The onset of the innate and adaptive immune response causes chronic and acute transplant rejection. Currently employed immunosuppressive medications have shown little or no influence on chronic rejection and, as a result, on overall long-term transplant survival. Furthermore, long-term pharmaceutical immunosuppression is associated with side effects, toxicity, and an increased risk of developing diseases, both infectious and metabolic. As a result, there is a need for the development of innovative donor-specific immunosuppressive medications to regulate the allorecognition pathways that induce graft loss and to reduce the side effects of immunosuppression. Efferocytosis is an immunomodulatory mechanism with fast and efficient clearance of apoptotic cells (ACs). As such, AC therapy strategies have been suggested to limit transplant-related sequelae. Efferocytosis-based medicines/treatments can also decrease the use of immunosuppressive drugs and have no detrimental side effects. Thus, this review aims to investigate the impact of efferocytosis on transplant rejection/tolerance and identify approaches using AC clearance to increase transplant viability.

Influence of donor capnometry on renal graft evolution in uncontrolled donation after circulatory death

Influence of donor capnometry on renal graft evolution in uncontrolled donation after circulatory death

Evaluation of NAG, NGAL, and KIM-1 as Prognostic Markers of the Initial Evolution of Kidney Transplantation.

Kidney transplantation is the best option for end-stage chronic kidney disease. Transplant viability is conditioned by drugs' nephrotoxicity, ischemia-reperfusion damage, or acute rejection. An approach to improve graft survival is the identification of post-transplant renal function prognostic biomarkers. Our objective was to study three early kidney damage biomarkers (N-acetyl-d-glucosaminidase, NAG; neutrophil gelatinase-associated lipocalin, NGAL; and kidney injury molecule-1, KIM-1) in the initial period after transplantation and to identify possible correlations with main complications. We analysed those biomarkers in urine samples from 70 kidney transplant patients. Samples were taken on days 1, 3, 5, and 7 after intervention, as well as on the day that renal function stabilised (based on serum creatinine). During the first week after transplant, renal function improved based on serum creatinine evolution. However, increasing levels of biomarkers at different times during that first week could indicate tubular damage or other renal pathology. A relationship was found between NGAL values in the first week after transplantation and delayed graft function. In addition, higher NAG and NGAL, and lower KIM-1 values predicted a longer renal function stabilisation time. Therefore, urinary NAG, NGAL, and KIM-1 could constitute a predictive tool for kidney transplant complications, contributing to improve graft survival rates.

Partial heart xenotransplantation: Aresearch protocol in non-human primates.

Partial heart transplantation is a new type of transplant that delivers growing heart valve replacements for babies. Partial heart transplantation differs from orthotopic heart transplantation because only the part of the heart containing the heart valve is transplanted. It also differs from homograft valve replacement because viability of the graft is preserved by tissue matching, minimizing donor ischemia times, and recipient immunosuppression. This preserves partial heart transplant viability and allows the grafts to fulfill biological functions such as growth and self-repair. These advantages over conventional heart valve prostheses are balanced by similar disadvantages as other organ transplants, most importantly limitations in donor graft availability. Prodigious progress in xenotransplantation promises to solve this problem by providing an unlimited source of donor grafts. In order to study partial heart xenotransplantation, a suitable large animal model is important. Here we describe our research protocol for partial heart xenotransplantation in nonhuman primates.

Capturing effects of blood flow on the transplanted decellularized nephron with intravital microscopy

Organ decellularization creates cell-free, collagen-based extracellular matrices that can be used as scaffolds for tissue engineering applications. This technique has recently gained much attention, yet adequate scaffold repopulation and implantation remain a challenge. Specifically, there still needs to be a greater understanding of scaffold responses post-transplantation and ways we can improve scaffold durability to withstand the in vivo environment. Recent studies have outlined vascular events that limit organ decellularization/recellularization scaffold viability for long-term transplantation. However, these insights have relied on in vitro/in vivo approaches that need enhanced spatial and temporal resolutions to investigate such issues at the microvascular level. This study uses intravital microscopy to gain instant feedback on their structure, function, and deformation dynamics. Thus, the objective of this study was to capture the effects of in vivo blood flow on the decellularized glomerulus, peritubular capillaries, and tubules after autologous and allogeneic orthotopic transplantation into rats. Large molecular weight dextran molecules labeled the vasculature. They revealed substantial degrees of translocation from glomerular and peritubular capillary tracks to the decellularized tubular epithelium and lumen as early as 12 h after transplantation, providing real-time evidence of the increases in microvascular permeability. Macromolecular extravasation persisted for a week, during which the decellularized microarchitecture was significantly and comparably compromised and thrombosed in both autologous and allogeneic approaches. These results indicate that in vivo multiphoton microscopy is a powerful approach for studying scaffold viability and identifying ways to promote scaffold longevity and vasculogenesis in bioartificial organs.

Dermatoplasty for decompensated forms of varicose veins and post-thrombotic syndrome

Objective(s). In order to improve the results of the treatment of the decompensated form of varicose veins and post-thrombotic syndrome, taking into account the angiosomal theory and using VAC and Magott therapy of the recipient woundof the trophic ulcer, evaluate different methods of dermatoplasty depending on the depth and area of the lesion. Methods. In the surgical clinic of the regional hospital named after A. Novak, 174 patients with chronic venous insufficiency (CVI) in the stage of lecompensation were under our observation. According to the etiology of the disease, there were 76 patients with varicose desease (VD) (group I), 98 patients with PTS (group II), while 27 patients with PTS had trophic ulcers on both lower extremities. With a trophic ulcer (TU) diameter of up to 10 cm in the I group of patients, 42.1% had the depth of the lesion of the IIst, and in the patients of the IIa group, the depth of the lesion was the IIIrd. was observed in 51.4% of cases. In the 1st group (76) patients, TU was cleaned with the help of VAC therapy in 32 patients, Magott therapy was used in 18 patients. TcpO2 was measured in the angiosomes of the anterior tibial artery (APA), posterior tibial artery (PTA), and peroneal artery (PA), as the corresponding arteries participate in the perfusion of the corresponding skin-muscle flaps Results. Rejection (lysis) of the graft was observed in 5 (6.6%) patients of the 1st group, and only in patients with dermatoplasty using the vintage method. Graft lysis was observed in 4 (5.6%) patients of the IIa group, in two with the vintage method and in two with split graft transplantation. In the IIb group (both limbs affected), partial lysis of the transplanted perforated split graft was observed in three limbs (6%). No complications were observed when the tissue complex was transplanted freely. Conclusions. Free flaps are units of tissue that can be transplanted from the donor site to the recipient wound while maintaining its blood supply. Pieces can be classified by the type of blood supply, their tissue composition, the method of transplantation, or the orientation of the vessels. The concept of angiosomes and venosomes explains the blood supply to the recipient wound necessary for the viability of the flap. Various monitoring methods are used to monitor patients after surgery, including assessment of physiological parameters and auxiliary methods (dopplerography, transcutaneous and epidermal oximetry). Factors affecting the viability of transplants after surgery include: thorough surgical intervention, adequate immobilization after surgery, prevention of infection, and adequate vascularization of the recipient wound.

Pancreatic Islet Biobanking Facilities in India: The Need of the Hour to Deal with Diabetes?

Endocrine pancreas regulates glucose homeostasis and prevents diabetes. Type-1 diabetes is characterized by destruction of the insulin secreting β-cells within the endocrine pancreatic islets, resulting in lower insulin release. People with type-1 diabetes can be transplanted with pancreatic islets obtained from deceased donors which restores the β-cell function. There are around 70 human islet isolation centers around the world which mostly collect endocrine pancreas from deceased donors. They assess the islet yield, functionality, viability, secretory capacity, and purity for transplantation and distribute this to donors. They also distribute a part of the pancreatic tissue for research, so that the cellular mechanisms in the human pancreatic tissue can be understood. This is crucial since human islet tissue has a unique cytoarchitecture compared to murine counterparts and therefore islet research with murine islets does not give complete picture of diabetes in humans. India is poised to take the mantle of the diabetes capital of the world in the near future. Despite this, there are no human islet isolation centers which can facilitate islet transplantation and diabetes research in India. This article highlights the glaring gap in the current infrastructure for diabetes care and provides critical insights into the role and potential of setting up islet tissue banks in the most populous country of the world.

Anatomical basis for pancreas transplantation via isolated splenic artery perfusion: A literature review.

The variability of vascular anatomy of the pancreas underlines the difficulty of its transplantation. Research regarding the consistency of anatomical variations shows splenic arterial dominance in most cases. This can significantly improve transplantation success. A systematic literature review was performed according to the quality standards described in the AMSTAR measurement tool and the PRISMA guidelines. We valuated existing literature regarding the vascularization and blood perfusion patterns of the pancreas in terms of dominance and variability. The collected data was independently analyzed by two researchers. Variance of vascular anatomy was seen to be underreported in literature, though significant findings have been included and discussed in this study, providing valuable insight into the dynamics of pancreatic perfusion and feasibility of transplantation on several different supplying arteries. The splenic artery (SA) has a high percentage of consistency in all found studies (over 90%). High frequency of anastomoses between arterial pools supplying the pancreas can mediate sufficient blood supply through a dominant vessel, such as the SA, which is present in most cases. Pancreatic transplantation with isolated SA blood supply can provide sufficient arterial perfusion of the pancreas for stable transplant viability due to high anatomical consistency of the SA and vast communications with other arterial systems.