A Review of Organ Transplantation: Heart, Lung, Kidney, Liver, and Simultaneous Liver-Kidney

Donors With Previous Malignancy: When Is It Safe to Proceed With Organ Transplantation?

The growing number of organ donors in the United States, from 14,011 in 2012 to 21,374 in 2022, highlights progress in addressing the critical issue of organ shortages. However, the demand remains high, with 17 patients dying daily while on the waiting list. As of August 2023, over 103,544 individuals are awaiting transplants, predominantly for kidneys (85.7%). To expand the donor pool, the inclusion of elderly donors, including those with a history of malignancies, is increasingly considered. In 2022, 7% of all donors were aged 65 and above, despite the complexities their medical histories may introduce, particularly the risk of donor-transmitted cancer (DTC). This review examines the challenges and potential benefits of using donors with known malignancy histories, balancing the risks of DTC against the urgency for transplants. A critical analysis is presented on current knowledge and the decision-making processes that consider cancer types, stages, and patient survival outcomes. The goal is to identify missed opportunities and improve strategies for safe and effective organ transplantation from this donor demographic.

Conversion of extracellular ATP into adenosine: a master switch in renal health and disease

ATP and its ultimate degradation product adenosine are potent extracellular signalling molecules that elicit a variety of pathophysiological functions in the kidney through the activation of P2 and P1 purinergic receptors, respectively. Extracellular purines can modulate immune responses, balancing inflammatory processes and immunosuppression; indeed, alterations in extracellular nucleotide and adenosine signalling determine outcomes of inflammation and healing processes. The functional activities of ectonucleotidases such as CD39 and CD73, which hydrolyse pro-inflammatory ATP to generate immunosuppressive adenosine, are therefore pivotal in acute inflammation. Protracted inflammation may result in aberrant adenosinergic signalling, which serves to sustain inflammasome activation and worsen fibrotic reactions. Alterations in the expression of ectonucleotidases on various immune cells, such as regulatory T cells and macrophages, as well as components of the renal vasculature, control purinergic receptor-mediated effects on target tissues within the kidney. The role of CD39 as a rheostat that can have an impact on purinergic signalling in both acute and chronic inflammation is increasingly supported by the literature, as detailed in this Review. Better understanding of these purinergic processes and development of novel drugs targeting these pathways could lead to effective therapies for the management of acute and chronic kidney disease.

Cost and Factors Associated With the Hospitalization of Patients Undergoing Heart Transplantation

OBJECTIVES

The aim of the study was to describe the cost and factors associated with the hospitalization of patients undergoing heart transplantation.

METHODS

A cross-sectional, descriptive study with a quantitative approach developed at an important heart transplant center in southern Brazil. Twenty patients who had undergone transplantation during the period 2007 to 2016 were included in the study. Central tendency measures and values presented as mean ± SD or median and quartiles were calculated. Multiple linear regression was performed to verify the variables that interfered with the cost.

RESULTS

The cost of hospitalization of patients undergoing heart transplantation was $522,997.26 in Brazilian reals ($220,002.58 in US dollars). The Brazilian public health system was responsible for paying the hospital bill of all patients. Female sex, patients up to 40 years of age, and length of stay in the hospital units were variables that were related to the highest values for the hospital service. Clinical complications of the patients during the hospitalization period were also factors that were related to the greater length of stay in the hospitalization units, reflecting higher expenses for the health institution.

CONCLUSIONS

There is a need for health managers to implement strategies that will minimize complications, such as health care-related infections, that can be prevented during hospitalization and to stimulate the allocation of resources in order to improve care and reduce hospital expenses.

Specific issues concerning the management of patients on the waiting list and after liver transplantation

The present document is a second contribution collecting the recommendations of an expert panel of transplant hepatologists appointed by the Italian Association for the Study of the Liver (AISF) concerning the management of certain aspects of liver transplantation, including: the issue of prompt referral; the management of difficult candidates; malnutrition; living related liver transplants; hepatocellular carcinoma; and the role of direct acting antiviral agents before and after transplantation. The statements on each topic were approved by participants at the AISF Transplant Hepatology Expert Meeting organized by the Permanent Liver Transplant Commission in Mondello on 12-13 May 2017. They are graded according to the GRADE grading system.

The role of exosomes in allograft immunity

Extracellular vesicles are emerging as potent vehicles of intercellular communication. In this review, we focus on a subclass of extracellular vesicles called exosomes. Previously considered an unimportant catch-all, exosomes have recently been recognized for their role in various diseases and their potential for therapeutic use. We have examined the role of exosomes after human lung transplantation and have delineated the composition of circulating exosomes isolated from lung transplant recipients diagnosed with acute and chronic rejection, primary graft dysfunction, and respiratory viral infection. The presence of lung-associated self-antigens (K-alpha 1 Tubulin and collagen V) and mismatched donor HLA in exosomes isolated from lung transplant recipients signifies that these exosomes originated in the transplanted lungs, and therefore dramatically affect transplant biology and immune pathways. Exosomes released from transplanted organs also carry other proteins, costimulatory molecules, and nucleic acids. Therefore, these molecules may be used as biomarkers for allograft rejection and immunity.

Cell-Surface Expression Levels Are Important for Fine-Tuning the Performance of Receptor Tyrosine Kinase-Based Signalobodies

As receptor tyrosine kinases (RTKs) play important roles in cell-fate control of various cell types, engineered RTKs that could respond to inexpensive ligands might drastically reduce the cost of producing desired cells for various applications in regenerative medicine. We developed several engineered RTKs named "signalobodies" in which the ligand-recognition domain of RTKs is replaced by single-chain Fv for enabling recognition of a specific antigen. However, the remaining concern was the dysregulation of antigen-dependent on/off signaling of the signalobodies. This study aims at fine-tuning the performance of the signalobodies based on three RTKs (fibroblast growth factor receptor 1, insulin receptor, and c-fms). To this end, the cell-surface expression levels of the RTK-based signalobodies were altered by locating their genes either upstream or downstream of the internal ribosomal entry site, and by inserting 1 to 3 alanine residue(s) at the intracellular juxtamembrane region. As a result, while the signaling response was different among the three signalobodies, the antigen-dependent on/off regulation became tighter when the cell-surface expression levels of the signalobodies were lowered. Therefore, we successfully developed a method to diminish the leaky signaling of RTK-based signalobodies, which will be important for establishing the signalobody-based platform technology that can produce cells of interest for regenerative medicine.