Design-encoded dual shape-morphing and shape-memory in 4D printed polymer parts toward cellularized vascular grafts.

Current additive manufacturing technologies wherein as-printed simple two-dimensional (2D) structures morph into complex tissue mimetic three-dimensional (3D) shapes are limited to multi-material hydrogel systems, which necessitates multiple fabrication steps and specific materials. This work utilizes a single shape memory thermoplastic polymer (SMP), PLMC (polylactide-co-trimethylene carbonate), to achieve programmable shape deformation through anisotropic design and infill angles encoded during 3D printing. The shape changes were first computationally predicted through finite element analysis (FEA) simulations and then experimentally validated through quantitative correlation. Rectangular 2D sheets could self-roll into complete hollow tubes of specific diameters (ranging from ≈6 mm to ≈10 mm) and lengths (as long as 40 mm), as quantitatively predicted from FEA simulations within one minute at relatively lower temperatures (≈80 °C). Furthermore, shape memory properties were demonstrated post-shape change to exhibit dual shape morphing at temperatures close to physiological levels. The tubes (retained as the permanent shape) were deformed into flat sheets (temporary shape), seeded with endothelial cells (at T < Tg), and thereafter triggered at ≈37 °C back into tubes (permanent shape), utilizing the shape memory properties to yield bioresorbable tubes with cellularized lumens for potential use as vascular grafts with improved long-term patency. Additionally, out-of-plane bending and twisting deformation were demonstrated in complex structures by careful control of infill angles that can unprecedently expand the scope of cellularized biomimetic 3D shapes. This work demonstrates the potential of the combination of shape morphing and SMP behaviors at physiological temperatures to yield next-generation smart implants with precise control over dimensions for tissue repair and regeneration.

Impact of Asian and Black Donor and Recipient Ethnicity on the Outcomes After Deceased Donor Kidney Transplantation in the United Kingdom.

Patients of Asian and black ethnicity face disadvantage on the renal transplant waiting list in the UK, because of lack of human leucocyte antigen and blood group matched donors from an overwhelmingly white deceased donor pool. This study evaluates outcomes of renal allografts from Asian and black donors. The UK Transplant Registry was analysed for adult deceased donor kidney only transplants performed between 2001 and 2015. Asian and black ethnicity patients constituted 12.4% and 6.7% of all deceased donor recipients but only 1.6% and 1.2% of all deceased donors, respectively. Unadjusted survival analysis demonstrated significantly inferior long-term allograft outcomes associated with Asian and black donors, compared to white donors. On Cox-regression analysis, Asian donor and black recipient ethnicities were associated with poorer outcomes than white counterparts, and on ethnicity matching, compared with the white donor-white recipient baseline group and adjusting for other donor and recipient factors, 5-year graft outcomes were significantly poorer for black donor-black recipient, Asian donor-white recipient, and white donor-black recipient combinations in decreasing order of worse unadjusted 5-year graft survival. Increased deceased donation among ethnic minorities could benefit the recipient pool by increasing available organs. However, it may require a refined approach to enhance outcomes.

Challenges With the Implementation of Machine Perfusion in Clinical Liver Transplantation.

Dynamic organ preservation is a relatively old technique which has regained significant interest in the last decade. Machine perfusion (MP) techniques are applied in various fields of solid organ transplantation today. The first clinical series of ex situ MP in liver transplantation was presented in 2010. Since then, the number of research and clinical applications has substantially increased. Despite the notable beneficial effect on organ quality and recipient outcome, MP is still not routinely used in liver transplantation. Based on the enormous need to better preserve organs and the subsequent demand to continuously innovate and develop perfusion equipment further, this technology is also beneficial to test and deliver future therapeutic strategies to livers before implantation. This article summarizes the various challenges observed during the current shift from static to dynamic liver preservation in the clinical setting. The different organ perfusion strategies are discussed first, together with ongoing clinical trials and future study design. The current status of research and the impact of costs and regulations is highlighted next. Factors contributing to costs and other required resources for a worldwide successful implementation and reimbursement are presented third. The impact of research on cost-utility and effectivity to guide the tailored decision-making regarding the optimal perfusion strategy is discussed next. Finally, this article provides potential solutions to the challenging field of innovation in healthcare considering the various social and economic factors and the role of clinical, regulatory, and financial stakeholders worldwide.

Emerging 4D fabrication of next-generation nerve guiding conduits: a critical perspective.

The latest advancements in the field of manufacturing for biomedicine, digital health, targeted therapy, and personalized medicine have fuelled the fabrication of smart medical devices. Four-dimensional (4D) fabrication strategies, which combine the manufacturing of three-dimensional (3D) parts with smart materials and/or design, have proved beneficial in creating customized and self-fitting structures that change their properties on demand with time. These frontier techniques that yield dynamic implants can indeed alleviate various drawbacks of current clinical practices, such as the use of sutures and complex microsurgeries and associated inflammation, among others. Among various clinical applications, 4D fabrication has lately made remarkable progress in the development of next-generation nerve-guiding conduits for treating peripheral nerve injuries (PNIs) by improving the end-to-end co-aptation of transected nerve endings. The current perspective highlights the relevance of 4D fabrication in developing state-of-the-art technologies for the treatment of PNIs. Various 4D fabrication/bio-fabrication techniques for PNI treatment are summarized while identifying the challenges and opportunities for the future. Such advancements hold immense promise for improving the quality of life of patients suffering from nerve damage and the potential for extending the treatment of many other disorders. Although the techniques are being described for PNIs, they will lend themselves suitably to certain cases of cranial nerve injuries as well.

Post Living Donor Liver Transplantation Small-for-size Syndrome: Definitions, Timelines, Biochemical, and Clinical Factors for Diagnosis: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference.

BACKGROUND: When a partial liver graft is unable to meet the demands of the recipient, a clinical phenomenon, small-for-size syndrome (SFSS), may ensue. Clear definition, diagnosis, and management are needed to optimize transplant outcomes. METHODS: A Consensus Scientific committee (106 members from 21 countries) performed an extensive literature review on specific aspects of SFSS, recommendations underwent blinded review by an independent panel, and discussion/voting on the recommendations occurred at the Consensus Conference. RESULTS: The ideal graft-to-recipient weight ratio of ≥0.8% (or graft volume standard liver volume ratio of ≥40%) is recommended. It is also recommended to measure portal pressure or portal blood flow during living donor liver transplantation and maintain a postreperfusion portal pressure of <15 mm Hg and/or portal blood flow of <250 mL/min/100 g graft weight to optimize outcomes. The typical time point to diagnose SFSS is the postoperative day 7 to facilitate treatment and intervention. An objective 3-grade stratification of severity for protocolized management of SFSS is proposed. CONCLUSIONS: The proposed grading system based on clinical and biochemical factors will help clinicians in the early identification of patients at risk of developing SFSS and institute timely therapeutic measures. The validity of this newly created grading system should be evaluated in future prospective studies.

Trends in Photopolymerizable Bioinks for 3D Bioprinting of Tumor Models.

Three-dimensional (3D) bioprinting technologies involving photopolymerizable bioinks (PBs) have attracted enormous attention in recent times owing to their ability to recreate complex structures with high resolution, mechanical stability, and favorable printing conditions that are suited for encapsulating cells. 3D bioprinted tissue constructs involving PBs can offer better insights into the tumor microenvironment and offer platforms for drug screening to advance cancer research. These bioinks enable the incorporation of physiologically relevant cell densities, tissue-mimetic stiffness, and vascularized channels and biochemical gradients in the 3D tumor models, unlike conventional two-dimensional (2D) cultures or other 3D scaffold fabrication technologies. In this perspective, we present the emerging techniques of 3D bioprinting using PBs in the context of cancer research, with a specific focus on the efforts to recapitulate the complexity of the tumor microenvironment. We describe printing approaches and various PB formulations compatible with these techniques along with recent attempts to bioprint 3D tumor models for studying migration and metastasis, cell-cell interactions, cell-extracellular matrix interactions, and drug screening relevant to cancer. We discuss the limitations and identify unexplored opportunities in this field for clinical and commercial translation of these emerging technologies.

NOTTO Guidelines for Vaccine Induced Thrombotic Thrombocytopenia in Organ Donation and Transplantation.

From the context of organ donation, COVID-19 vaccine-induced thrombotic thrombocytopenia (VITT) is important as there is an ethical dilemma in utilizing versus discarding organs from potential donors succumbing to VITT. This consensus statement is an attempt by the National Organ and Tissue Transplant Organization (NOTTO) apex technical committees India to formulate the guidelines for deceased organ donation and transplantation in relation to VITT to help in appropriate decision making. VITT is a rare entity, but a meticulous approach should be taken by the Organ Procurement Organization's (OPO) team in screening such cases. All such cases must be strictly notified to the national authorities like NOTTO, as a resource for data collection and ensuring compliance withprotocols in the management of adverse events following immunization. Organs from any patient who developed thrombotic events up to 4 weeks after adenoviral vector-based vaccination should be linked to VITT and investigated appropriately. The viability of the organs must be thoroughly checked by the OPO, and the final decision in relation to organ use should be decided by the expert committee of the OPO team consisting of a virologist, a hematologist, and atreating team. Considering the organ shortage, in case of suspected/confirmed VITT, both clinicians and patients should consider the risk-benefit equationbased on available experience, and an appropriate written informed consent of potential recipients and family members should be obtained before transplantation of organs from suspected or proven VITT donors.

National Liver Allocation Policy-Consensus Document by the Liver Transplantation Society of India for a Nationally Uniform System of Allocation of Deceased Donor Liver Grafts.

Background: Deceased donor liver transplantation (DDLT) is increasing in India and now constitutes nearly one-third of all liver transplantation procedures performed in the country. There is currently no uniform national system of allocation of deceased donor livers. Methods: A national task force consisting of 19 clinicians involved in liver transplantation from across the country was constituted under the aegis of the Liver Transplantation Society of India to develop a consensus document addressing the above issues using a modified Delphi process of consensus development. Results: The National Liver Allocation Policy consensus document includes 46 statements covering all aspects of DDLT, including minimum listing criteria, listing for acute liver failure, DDLT wait-list management, system of prioritisation based on clinical urgency for adults and children, guidelines for allocation of paediatric organs and allocation priorities for liver grafts recovered from public sector hospitals. Conclusion: This document is the first step in the setting up of a nationally consistent policy of deceased donor liver allocation.

Rapid, adaptable and sensitive Cas13-based COVID-19 diagnostics using ADESSO.

During the ongoing COVID-19 pandemic, PCR testing and antigen tests have proven critical for helping to stem the spread of its causative agent, SARS-CoV-2. However, these methods suffer from either general applicability and/or sensitivity. Moreover, the emergence of variant strains creates the need for flexibility to correctly and efficiently diagnose the presence of substrains. To address these needs we developed the diagnostic test ADESSO (Accurate Detection of Evolving SARS-CoV-2 through SHERLOCK (Specific High Sensitivity Enzymatic Reporter UnLOCKing) Optimization) which employs Cas13 to diagnose patients in 1 h without sophisticated equipment. Using an extensive panel of clinical samples, we demonstrate that ADESSO correctly identifies infected individuals at a sensitivity and specificity comparable to RT-qPCR on extracted RNA and higher than antigen tests for unextracted samples. Altogether, ADESSO is a fast, sensitive and cheap method that can be applied in a point of care setting to diagnose COVID-19 and can be quickly adjusted to detect new variants.

Emerging trends in biliary stents: a materials and manufacturing perspective.

Biliary stent technology has come a long way since its inception. There have been significant advancements in the materials used, and design and deployment strategies. Options have expanded from plastic and metallic stents to a wider variety of materials and manufacturing technologies to offer several options to clinicians, including self-expandable metallic stents and bioresorbable stents. Bioresorbable biliary stents are still in the early stages of clinical adoption. This review encompasses the materials currently used for biliary stents and the significant developments in the past few years in the resorbable materials for use as biliary stents. We critically discuss the emerging trends in the development of new resorbable materials for fabricating biliary stents. We then assess the developments in drug-eluting stents and advanced manufacturing technologies that could be leveraged for biliary stents. Challenges in the paths for translation for the future, such as pre-clinical and clinical trials, are highlighted. Finally, we present future directions that could drive the biliary stent market to meet the increasingly complex and diverse clinical needs of patients.

A New Variant of an Old Itch: Novel Missense Variant in ABCB4 Presenting with Intractable Pruritus.

We report a novel homozygous missense variant in ABCB4 gene in a Yemeni child born to consanguineous parents, with a significant family history of liver disease-related deaths, resulting in a progressive familial intrahepatic cholestasis (PFIC) type 3 phenotype requiring liver transplantation for intractable pruritus.

Liver Transplant Society of India Guidelines for Liver Transplant During COVID-19 times.

Coronavirus disease-2019 (COVID-19) pandemic has affected liver transplantation in many ways. There is risk of infection to the transplant recipients; and COVID-19 is associated with significant risk of mortality in patients on wait list. The Liver Transplant Society of India (LTSI) has prepared guidelines regarding selection of adult and pediatric patients for liver transplantation, transplant for acute liver failure, use of deceased donor organs, transplant techniques and minimally invasive donor hepatectomy, pre- and postsurgery testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related coronavirus disease 2019 in donors and recipients, role of COVID-19 antibody testing, shifting of recipients from COVID-19 to non-COVID-19 areas after recovery, isolation policy of team members exposed to COVID-19 patients, drug therapy of proven or suspected COVID-19 infection early posttransplant, care of SARS-CoV-2 positive donors and recipients and a separate COVID-19 consent for surgery.

The Use of a 3D Printing Model in Planning a Donor Hepatectomy for Living Donor Liver Transplantation: First in India.

INTRODUCTION: Three-dimensional (3D) anatomical relationships between the hepatic veins and portal structures can serve as a guide to plan resections in donor hepatectomy during living donor liver transplantation. We present the first case report from India on the use of a 3D printed liver model, as an assist to living donor liver transplantation. METHODS: A 3D model of the donor liver with hepatic venous structures printed within it was prepared using image acquisition data. The model was used for a simulated cut preoperatively, to mimic the donor hepatectomy based on the venous structures seen through the transparent material used for making the liver model. The volume of the graft measured by volume displacement in the actual surgery was compared with the volume of the model after the simulated cut. RESULTS: The calculated volume of the graft was 359 ml as per the preoperative simulation, and the observed weight/volume was 380 gm/310 ml. CONCLUSION: Three-dimensional printing of liver models using imaging data can help predict the actual size of the graft after donor hepatectomy, in patients undergoing living donor liver transplantation.

Primary hepatic neuroendocrine tumor: A rare entity.

Liver is the most common site for neuroendocrine metastasis. However, primary neuroendocrine tumor is a rare focal hepatic lesion with a better prognosis than hepatocellular carcinoma and other malignant hepatic lesions. We present a case of primary hepatic neuroendocrine tumor in a 38-year-old female patient with a radiological diagnosis of atypical focal hepatic lesion, and a confirmed diagnosis on histopathology. Few radiology features like predominant cystic component with absence of focal lesion at any other site, aids the imaging diagnosis of primary hepatic neuroendocrine tumor.

Liver transplantation and COVID-19 (Coronavirus) infection: guidelines of the liver transplant Society of India (LTSI).

The Liver Transplant Society of India (LTSI) has come up with guidelines for transplant centres across the country to deal with liver transplantation during this evolving pandemic of COVID-19 infection. The guidelines are applicable to both deceased donor as well as living donor liver transplants. In view of the rapidly changing situation of COVID-19 infection in India and worldwide, these guidelines will need to be updated according to the emerging data.

Hepatic arterial communicating arcades-Case series and review of literature.

This case series describes the hepatic arterial communicating arcades and their importance in the endovascular management of hepatic artery pseudoaneurysm, pediatric post liver transplant lobar arterial occlusion, and lobar arterial stenosis due to gall bladder carcinoma. We describe new types of arterial communicating arcades which have not been described earlier.

Diaphragmatic herniation following donor hepatectomy for living donor liver transplantation: a serious complication not given due recognition.

A clear appreciation of benefits and risks associated with living donor hepatectomy is important to facilitate counselling for the donor, family, and recipient in preparation for living donor liver transplant (LDLT). We report a life-threatening complication occurring in one of our live liver donors at 12 weeks following hemi-liver donation. We experienced five donor complications among our first 50 LDLT: Clavien Grade 1, n=1; Clavien grade 2, n=3; and Clavien grade 3B, n=1. The one with Clavien grade 3B had a life-threatening diaphragmatic hernia occurring 12 weeks following hepatectomy. This was promptly recognized and emergency surgery was performed. The donor is well at 1-year follow-up. Here we provide a review of reported instances of diaphragmatic hernia following donor hepatectomy with an attempt to elucidate the pathophysiology behind such occurrence. Life-threatening donor risk needs to be balanced with recipient benefit and risk on a tripartite basis during the counselling process for LDLT. With increasing use of LDLT, we need to be aware of such life-threatening complication. Preventive measures in this regard and counselling for such complication should be incorporated into routine work-up for potential live liver donor.

Detection of Carbapenemase Production in Gram-negative Bacteria.

The greatest threat to antimicrobial treatment of infections caused by Gram-negative bacteria is the production of carbapenemases. Metallo-beta-lactamases and plasmid-mediated serine carbepenemases like Klebsiella pneumonia carbapenemase are threatening the utility of almost all currently available beta-lactams including carbapenems. Detection of organisms producing carbapenemases can be difficult, because their presence does not always produce a resistant phenotype on conventional disc diffusion or automated susceptibility testing methods. These enzymes are often associated with laboratory reports of false susceptibility to carbapenems which can be potentially fatal. Moreover, most laboratories do not attempt to detect carbapenemases. This may be due to the lack of availability of guidelines and procedures or lack of knowledge and expertise. Because routine susceptibility tests may be unreliable, special tests are required to detect the resistance mechanisms involved. This document describes the standard methodology for detection of various types of carbapenemases, which can be put to use by laboratories working on antimicrobial resistance in Gram-negative bacteria.