Freezing Biological Time: A Modern Perspective on Organ Preservation.

Transporting tissues and organs from the site of donation to the patient in need, while maintaining viability, is a limiting factor in transplantation medicine. One way in which the supply chain of organs for transplantation can be improved is to discover novel approaches and technologies that preserve the health of organs outside of the body. The dominant technologies that are currently in use in the supply chain for biological materials maintain tissue temperatures ranging from a controlled room temperature (+25 °C to +15 °C) to cryogenic (-120 °C to -196 °C) temperatures (reviewed in Criswell et al. Stem Cells Transl Med. 2022). However, there are many cells and tissues, as well as all major organs, that respond less robustly to preservation attempts, particularly when there is a need for transport over long distances that require more time. In this perspective article, we will highlight the current challenges and advances in biopreservation aimed at "freezing biological time," and discuss the future directions and requirements needed in the field.

Psychological Distress and Its Association With Quality of Life in Organ Transplant Recipients During COVID-19 Pandemic.

Objectives: The coronavirus disease 2019 (COVID-19) pandemic may have an impact on the psychological distress of organ transplant recipients. We aimed to assess the status of psychological distress and its association with quality of life (QoL) in organ transplant recipients during the COVID-19 pandemic. Materials and Methods: A cross-sectional survey was carried out with 305 organ transplant recipients during March 30 and April 2, 2020, in Wuhan. Psychological distress comprised depression, anxiety, insomnia, and post-traumatic stress disorder (PTSD), which were assessed using the Patient Health Questionnaire-9, the seven-item Generalized Anxiety Disorder questionnaire, the Insomnia Severity Index, and Impact of event scale-revised. QoL was assessed using the Chinese version of the short Form 36-item health survey. Results: The prevalence of depression, anxiety, insomnia, and PTSD in organ transplant recipients was 13.4, 6.9, 11.8, and 30.5%, respectively. Organ transplant recipients with depression had significantly lower scores in all eight dimensions of QoL compared with participants without depression (all p < 0.05). Lower scores on the QoL dimensions of role physical, bodily pain, general health, vitality, role emotional, and mental health were found in organ transplant recipients with anxiety, insomnia, or PTSD compared with their counterparts without the respective disorder (all p < 0.05). Limitation: The cross-sectional study design limited us to make causal conclusion and the influence of potential confounders cannot be ruled out. Conclusions: Psychological distress was prevalent in organ transplant recipients during the COVID-19 pandemic, and those with depression, anxiety, insomnia, and PTSD had poorer QoL. Therefore, timely psychological counseling, COVID-19 related health education, and essential community medical services should be provided to organ transplant recipients to relieve their psychological distress, and to improve their QoL.

Evidence that human and equine erythrocytes could have significant roles in the transport and delivery of amino acids to organs and tissues.

Erythrocytes have a well-defined role in the gaseous exchange of oxygen and carbon dioxide in the mammalian body. The erythrocytes can contain more than half of the free amino acids present in whole blood. Based on measures showing that venous erythrocyte levels of amino acids are much less than arterial erythrocyte levels, it has previously been proposed that erythrocytes also play a role in the delivery of amino acids to tissues in the body. This role has been dismissed because it has been assumed that to act as an amino acid transport vehicle, the erythrocytes should release their entire amino acid content in the capillary beds at the target tissues with kinetic studies showing that this would take too long to achieve. This investigation set out to investigate whether the equine erythrocytes could rapidly take up and release smaller packages of amino acids when exposed to high or low external concentrations of amino acids, because it seemed very unlikely that cells would be able to release all of their amino acids without serious impacts on osmotic balance. Freshly prepared erythrocytes were placed in alternating solutions of high and low amino acid concentrations in PBS to assess the capacities of these cells to rapidly take up and release amino acids depending on the nature of the external environment. It was found that amino acids were rapidly taken up and released in small quantities in each cycle representing 15% of their total load in equine erythrocytes and 16% in human erythrocytes. The capacity for rapid uptake/release of amino acids by equine and human erythrocytes provided evidence to support the theory that mammalian erythrocytes have a significant role in transport of amino acids from the liver to tissues, muscles and organs.

Lysosome-Rich Enterocytes Mediate Protein Absorption in the Vertebrate Gut.

The guts of neonatal mammals and stomachless fish have a limited capacity for luminal protein digestion, which allows oral acquisition of antibodies and antigens. However, how dietary protein is absorbed during critical developmental stages when the gut is still immature is unknown. Here, we show that specialized intestinal cells, which we call lysosome-rich enterocytes (LREs), internalize dietary protein via receptor-mediated and fluid-phase endocytosis for intracellular digestion and trans-cellular transport. In LREs, we identify a conserved endocytic machinery, composed of the scavenger receptor complex Cubilin/Amnionless and Dab2, that is required for protein uptake by LREs and for growth and survival of larval zebrafish. Moreover, impairing LRE function in suckling mice, via conditional deletion of Dab2, leads to stunted growth and severe protein malnutrition reminiscent of kwashiorkor, a devastating human malnutrition syndrome. These findings identify digestive functions and conserved molecular mechanisms in LREs that are crucial for vertebrate growth and survival.

Challenges of kidney paired donation transplants involving multiple donor and recipient surgeons across Australia.

BACKGROUND: The Australian kidney paired donation program adopted the principles of within-chain simultaneous live donor surgery and of organ transport, with the requirement of keeping cold ischemia time (CIT) to <12 h. Whether these principles could be adhered to and what impact on transplant outcome they might have is unknown. METHODS: We evaluated the logistic challenges and outcomes of the first 100 kidney transplants performed in the Australian kidney paired donation program. RESULTS: Within 4 years, 17 donor surgeons at 12 centres were involved in 37 chain exchange surgeries. Sixteen kidneys were transplanted at the same hospital and 84 required transport to the recipient hospital. Mean (±SD) within chain anaesthetic induction time variability was 8 ± 18 min and mean individual surgeon operating time was 115 ± 44 min. In two cases, delays during donor surgery resulted in increased CIT by 1 h because of deferred transport. CIT was 2.6 ± 0.6 h for non-shipped and 6.8 ± 2.8 h for shipped kidneys, four kidneys had CIT of 12-14 h. Immediate allograft function was observed in 85% of recipients, with no difference between shipped and non-shipped kidneys. There were only two cases of delayed graft function requiring temporary dialysis; both had CIT <7 h. There was no difference in serum creatinine at 1 month between non-shipped and shipped kidneys (105 ± 26 versus 112 ± 50 µmol/L) and allograft survival at 1 year was 97%. CONCLUSION: The study provided a favourable audit of kidney transplant activity, despite challenges of simultaneous surgery, organ transport coordination and prolonged CIT. The decision to ship donor kidneys rather than the donor was demonstrated to be feasible and safe.

Outcomes of kidney paired donation transplants in relation to shipping and cold ischaemia time.

To assess the impact of shipping distance and cold ischaemia time (CIT) of shipped organs in a kidney paired donation (KPD) programme, we evaluated the outcomes of the initial 100 kidney transplants performed in the Australian KPD programme. In a 44-month period, 12 centres were involved in fifteen 2-way, twenty 3-way, one 4-way and one 6-way exchanges. Sixteen kidneys were transplanted at the same hospital (CIT 2.6 ± 0.6 h) and 84 required transport to the recipient hospital (CIT 6.8 ± 2.8 h). A spontaneous fall in serum creatinine by at least 10% within 24 h was observed in 85% of recipients, with no difference between nonshipped and shipped kidneys. There were two cases of transient delayed graft function requiring dialysis and patient and graft survival at 1 year were 99% and 97%, respectively. There was no difference in recipients of nonshipped compared with shipped kidneys with regard to serum creatinine at 1 month (mean difference (MD) 7.3 µmol/l, 95% CI -20.2 to 34.8, P = 0.59), 1-year graft survival (MD 3.9%, 95% CI -5.4 to 13.2, P = 0.41) or patient survival (MD -2.4%, 95% CI -10.0 to 5.2, P = 0.54). Despite prolonged CIT for interstate exchanges, the programme's decision to ship donor kidneys rather than the donor appears to be safe.

Frostbite of the liver: an unrecognized cause of primary non-function?

Appropriate hypothermic packaging techniques are an essential part of organ procurement. We present a case in which deviation from standard packaging practice may have caused sub-zero storage temperatures during transport, resulting in a clinical picture resembling PNF. An 18-month-old male with alpha-1-antitrypsin deficiency underwent liver transplant from a size-matched pediatric donor. Upon arrival at the recipient hospital, ice crystals were noted in the UW solution. The transplant proceeded uneventfully with short ischemia times. Surprisingly, transaminases, INR, and total bilirubin were markedly elevated in the postoperative period but returned to near normal by discharge. Follow-up of over five yr has demonstrated normal liver function. Upon review, it was discovered that organ packaging during recovery included storage in the first bag with only 400 mL of UW solution, and pure ice in the second bag instead of slush. This suggests that the postoperative delayed graft function was related to sub-zero storage of the graft during transport. This is the first report of sub-zero cold injury, or frostbite, following inappropriate packaging of an otherwise healthy donor liver. The clinical picture closely resembled PNF, perhaps implicating this mechanism in other unexpected cases of graft non-function.