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Cellular recovery after prolonged warm ischaemia of the whole body

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David Andrijevic at Yale University
David Andrijevic
Zvonimir Vrselja at Yale University
Zvonimir Vrselja
Taras Lysyy at Yale University
Taras Lysyy
Shupei Zhang
Shupei Zhang
Shupei Zhang
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Abstract and Figures

After cessation of blood flow or similar ischaemic exposures, deleterious molecular cascades commence in mammalian cells, eventually leading to their death1,2. Yet with targeted interventions, these processes can be mitigated or reversed, even minutes or hours post mortem, as also reported in the isolated porcine brain using BrainEx technology3. To date, translating single-organ interventions to intact, whole-body applications remains hampered by circulatory and multisystem physiological challenges. Here we describe OrganEx, an adaptation of the BrainEx extracorporeal pulsatile-perfusion system and cytoprotective perfusate for porcine whole-body settings. After 1 h of warm ischaemia, OrganEx application preserved tissue integrity, decreased cell death and restored selected molecular and cellular processes across multiple vital organs. Commensurately, single-nucleus transcriptomic analysis revealed organ- and cell-type-specific gene expression patterns that are reflective of specific molecular and cellular repair processes. Our analysis comprises a comprehensive resource of cell-type-specific changes during defined ischaemic intervals and perfusion interventions spanning multiple organs, and it reveals an underappreciated potential for cellular recovery after prolonged whole-body warm ischaemia in a large mammal. OrganEx—an extracorporeal pulsatile-perfusion system with cytoprotective perfusate for porcine whole-body settings—preserved tissue integrity, decreased cell death and restored selected molecular and cellular processes across multiple vital organs after 1 h of warm ischaemia in pigs.
Overview of the OrganEx technology and the experimental workflow a, Connection of the porcine body to the OrganEx perfusion system (or ECMO, not shown) through cannulation of the femoral artery and vein. b, Simplified schematic of the OrganEx perfusion device. The system is equipped with a centrifugal pump, pulse generator, haemodiafiltration, gas infusion, drug-delivery systems and sensors to measure metabolic and circulation parameters. c, Schematic of the experimental workflow and conditions. VF, ventricular fibrillation.
Overview of the OrganEx technology and the experimental workflow a, Connection of the porcine body to the OrganEx perfusion system (or ECMO, not shown) through cannulation of the femoral artery and vein. b, Simplified schematic of the OrganEx perfusion device. The system is equipped with a centrifugal pump, pulse generator, haemodiafiltration, gas infusion, drug-delivery systems and sensors to measure metabolic and circulation parameters. c, Schematic of the experimental workflow and conditions. VF, ventricular fibrillation.
… 
Circulation and blood/perfusate properties during the perfusion protocols a,b, Representative images of abdominal fluoroscopy (a; n = 9) and ophthalmic and renal ultrasound (b; n = 6) after 3 h of perfusion. ECMO is shown at the top and OrganEx is shown at the bottom. c., colour; RI, resistive index. c–e, Changes in the total flow rate and brachial arterial pressure (c), the percentage of venous O2 saturation (d) and K⁺ concentration and pH in the serum (e) throughout the perfusion protocols. n = 6. For c–e, data are mean ± s.e.m. Statistical analysis was performed using unpaired two-tailed t-tests; **P < 0.01, ***P < 0.001; NS, not significant. Further detailed information on statistics and reproducibility are provided in the Methods.
Circulation and blood/perfusate properties during the perfusion protocols a,b, Representative images of abdominal fluoroscopy (a; n = 9) and ophthalmic and renal ultrasound (b; n = 6) after 3 h of perfusion. ECMO is shown at the top and OrganEx is shown at the bottom. c., colour; RI, resistive index. c–e, Changes in the total flow rate and brachial arterial pressure (c), the percentage of venous O2 saturation (d) and K⁺ concentration and pH in the serum (e) throughout the perfusion protocols. n = 6. For c–e, data are mean ± s.e.m. Statistical analysis was performed using unpaired two-tailed t-tests; **P < 0.01, ***P < 0.001; NS, not significant. Further detailed information on statistics and reproducibility are provided in the Methods.
… 
Analysis of tissue integrity across experimental conditions and organs a, Representative confocal images of immunofluorescence staining for neurons (NeuN), astrocytes (GFAP) and microglia (IBA1) counterstained with DAPI nuclear stain in the hippocampal CA1 region. b–d, Quantification of NeuN immunoreactivity intensity (b), the number of GFAP fragments (c) and the microglia number (d) in the CA1. n = 3. e, Representative images of H&E staining in the heart, liver and kidneys. f–h, Evaluation of histopathological criteria, including nuclear pyknosis (arrow), tissue integrity (asterisk), haemorrhage/congestion (empty arrowhead), cell vacuolization (full arrowhead) and tissue oedema (double arrow) in the heart (f), liver (g) and kidneys (h). n = 5. i–k, Representative confocal images of immunofluorescence staining for ACTB in the kidneys (i) and its quantification in the glomerulus (j) and proximal convoluted tubule (PCT) (k). n = 3. Scale bars, 40 μm. For b–d, f–h, j and k, data are mean ± s.e.m. Statistical analysis was performed using one-way analysis of variance (ANOVA) with post hoc Dunnett adjustment; *P < 0.05, **P < 0.01, ***P < 0.001. Further detailed information on statistics and reproducibility are provided in the Methods.
Analysis of tissue integrity across experimental conditions and organs a, Representative confocal images of immunofluorescence staining for neurons (NeuN), astrocytes (GFAP) and microglia (IBA1) counterstained with DAPI nuclear stain in the hippocampal CA1 region. b–d, Quantification of NeuN immunoreactivity intensity (b), the number of GFAP fragments (c) and the microglia number (d) in the CA1. n = 3. e, Representative images of H&E staining in the heart, liver and kidneys. f–h, Evaluation of histopathological criteria, including nuclear pyknosis (arrow), tissue integrity (asterisk), haemorrhage/congestion (empty arrowhead), cell vacuolization (full arrowhead) and tissue oedema (double arrow) in the heart (f), liver (g) and kidneys (h). n = 5. i–k, Representative confocal images of immunofluorescence staining for ACTB in the kidneys (i) and its quantification in the glomerulus (j) and proximal convoluted tubule (PCT) (k). n = 3. Scale bars, 40 μm. For b–d, f–h, j and k, data are mean ± s.e.m. Statistical analysis was performed using one-way analysis of variance (ANOVA) with post hoc Dunnett adjustment; *P < 0.05, **P < 0.01, ***P < 0.001. Further detailed information on statistics and reproducibility are provided in the Methods.
… 
Functional characterization and metabolic activity of selected organs a–c, Measurement of 2-NBDG uptake in the brain (a), heart (b) and kidney (c). n = 3. d, Observed QRS complexes in ECMO- and OrganEx-treated animals 3 h into the perfusion period (left). Statistical analysis was performed using χ² tests. Right, representative EKG trances in the OrganEx and ECMO groups 3 h into the perfusion period. e, Measurement of cardiomyocyte contraction velocity in acute heart slices in the 0 h WIT, OrganEx and ECMO groups (left), and cardiomyocyte contraction duration (right). n = 5. f, Representative confocal images of immunolabelling for albumin in the liver. Scale bars, 50 μm. g, Measurement of normalized immunolabelling signal intensity of albumin in the liver demonstrating similar expression between the OrganEx and 0 h WIT groups. n = 3. h, Representative images of organotypic hippocampal slices after 1 and 14 days in culture. Scale bar, 500 μm. i, Quantification of hippocampal slice integrity. n = 4–5. j, Representative confocal images of newly synthesized proteins (AHA, Click-iT Chemistry) with DAPI counterstaining in the long-term organotypic hippocampal slice culture. Scale bar, 100 μm. k, Quantification of AHA relative intensity in the CA1. n = 3–5. For a–c, g, i and k, data are mean ± s.e.m. Statistical analysis was performed using one-way ANOVA with post hoc Dunnett adjustment; *P < 0.05, **P < 0.01, ***P < 0.001. AU, arbitrary units. HIP, hippocampus.
Functional characterization and metabolic activity of selected organs a–c, Measurement of 2-NBDG uptake in the brain (a), heart (b) and kidney (c). n = 3. d, Observed QRS complexes in ECMO- and OrganEx-treated animals 3 h into the perfusion period (left). Statistical analysis was performed using χ² tests. Right, representative EKG trances in the OrganEx and ECMO groups 3 h into the perfusion period. e, Measurement of cardiomyocyte contraction velocity in acute heart slices in the 0 h WIT, OrganEx and ECMO groups (left), and cardiomyocyte contraction duration (right). n = 5. f, Representative confocal images of immunolabelling for albumin in the liver. Scale bars, 50 μm. g, Measurement of normalized immunolabelling signal intensity of albumin in the liver demonstrating similar expression between the OrganEx and 0 h WIT groups. n = 3. h, Representative images of organotypic hippocampal slices after 1 and 14 days in culture. Scale bar, 500 μm. i, Quantification of hippocampal slice integrity. n = 4–5. j, Representative confocal images of newly synthesized proteins (AHA, Click-iT Chemistry) with DAPI counterstaining in the long-term organotypic hippocampal slice culture. Scale bar, 100 μm. k, Quantification of AHA relative intensity in the CA1. n = 3–5. For a–c, g, i and k, data are mean ± s.e.m. Statistical analysis was performed using one-way ANOVA with post hoc Dunnett adjustment; *P < 0.05, **P < 0.01, ***P < 0.001. AU, arbitrary units. HIP, hippocampus.
… 
Organ- and cell-type-specific transcriptomic changes assessed by snRNA-seq across various warm ischaemia intervals and different perfusion interventions a–d, Uniform manifold approximation and projection (UMAP) layout showing major t-types in the hippocampus (a), heart (b), liver (c) and kidneys (d) (top). Middle, comparison of averaged Augur area under the curve (AUC) scores across the t-types indicating which cell type underwent the most transcriptomic changes. Bottom, P values of gene set enrichment of gene sets that are important in cellular recovery and specific cellular functions in major respective t-types. **P < 0.01, ***P < 0.001. FA, fatty acid.
Organ- and cell-type-specific transcriptomic changes assessed by snRNA-seq across various warm ischaemia intervals and different perfusion interventions a–d, Uniform manifold approximation and projection (UMAP) layout showing major t-types in the hippocampus (a), heart (b), liver (c) and kidneys (d) (top). Middle, comparison of averaged Augur area under the curve (AUC) scores across the t-types indicating which cell type underwent the most transcriptomic changes. Bottom, P values of gene set enrichment of gene sets that are important in cellular recovery and specific cellular functions in major respective t-types. **P < 0.01, ***P < 0.001. FA, fatty acid.
… 
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Nature | Vol 608 | 11 August 2022 | 405
Article
Cellular recovery after prolonged warm
ischaemia of the whole body
David Andrijevic1,18, Zvonimir Vrselja1,18, Taras Lysyy1,2,18, Shupei Zhang1,3,18, Mario Skarica1,
Ana Spajic1, David Dellal1,4, Stephanie L. Thorn5, Robert B. Duckrow6, Shaojie Ma1,
Phan Q. Duy1,7,8 , Atagun U. Isiktas1, Dan Liang1, Mingfeng Li1, Suel-Kee Kim1,
Stefano G. Daniele1,8, Khadija Banu9, Sudhir Perincheri10, Madhav C. Menon9, Anita Huttner10,
Kevin N. Sheth6,7, Kevin T. Gobeske6, Gregory T. Tietjen2,4, Hitten P. Zaveri6,
Stephen R. Latham11, Albert J. Sinusas3,4,12,13 & Nenad Sestan1,3,14,15,1 6,17 ✉
After cessation of blood ow or similar ischaemic exposures, deleterious molecular
cascades commence in mammalian cells, eventually leading to their death1,2. Yet with
targeted interventions, these processes can be mitigated or reversed, even minutes or
hours post mortem, as also reported in the isolated porcine brain using BrainEx
technology3. To date, translating single-organ interventions to intact, whole-body
applications remains hampered by circulatory and multisystem physiological
challenges. Here we describe OrganEx, an adaptation of the BrainEx extracorporeal
pulsatile-perfusion system and cytoprotective perfusate for porcine whole-body
settings. After 1 h of warm ischaemia, OrganEx application preserved tissue integrity,
decreased cell death and restored selected molecular and cellular processes across
multiple vital organs. Commensurately, single-nucleus transcriptomic analysis
revealed organ- and cell-type-specic gene expression patterns that are reective of
specic molecular and cellular repair processes. Our analysis comprises a
comprehensive resource of cell-type-specic changes during dened ischaemic
intervals and perfusion interventions spanning multiple organs, and it reveals an
underappreciated potential for cellular recovery after prolonged whole-body warm
ischaemia in a large mammal.
Mammalian cells require oxygen to maintain cellular and tissue viability4.
In just minutes after ischaemia, intracellular acidosis and oedema
develop and trigger secondary injury to membranes and organelles,
often causing cell death1. At the whole-body scale, there is a systemic
release of hormones and cytokines, followed by activation of autonomic
nervous, immune and coagulation systems, leading to end-organ injury
culminating in systemic metabolic acidosis and hyperkalaemia2,5,6.
However, recent studies question the inevitability of cell death even
after hours of circulatory interruption. Viable cells can be collected
from multiple organs and maintained using invitro culture after
prolonged ischaemia
7
. Similarly, cellular recovery can be promoted
using ex vivo perfusion of isolated whole organs, including heart, liver,
kidneys and lungs
8–11
. Our perfusion-based BrainEx technology also
demonstrated restored circulation and cellular activity hours post
mortem in isolated porcine brains—the organ that is most vulnerable
to ischaemia2,6.
Nevertheless, translating solutions from isolated-organ models
for molecular and cellular recovery to whole-body applications after
extended ischaemia still presents substantial challenges. Reperfu-
sion of the whole body with autologous blood has several hindrances,
including coagulation, microvascular dysfunction, inflammation and
blood-intrinsic cellular dysfunction
2,5
. This has restricted whole-body
reperfusion and recovery times to 20 min in large mammals12, although
catastrophic/fatal consequences are widespread after several minutes
in humans
13
. A new approach may reinstate systemic circulation while
adding targeted molecular and cellular recovery strategies for specific
organs in the whole-body setting. From this, achieving recovery after
1 h of warm ischaemia may facilitate the development of opportunities
across various clinical disciplines.
Towards these goals, we translated principles from BrainEx technol-
ogy3 to develop OrganEx, a perfusion system and synthetic, acellular,
cytoprotective perfusate, for whole-body use in large mammals. We
https://doi.org/10.1038/s41586-022-05016-1
Received: 9 September 2021
Accepted: 23 June 2022
Published online: 3 August 2022
Check for updates
1Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA. 2Department of Surgery, Yale School of Medicine New Haven, New Haven, CT, USA. 3Department of Genetics, Yale
School of Medicine, New Haven, CT, USA. 4Department of Biomedical Engineering, Yale University, New Haven, CT, USA. 5Yale Translational Research Imaging Center, Department of Medicine,
Yale School of Medicine, New Haven, CT, USA. 6Department of Neurology, Yale University School of Medicine, New Haven, CT, USA. 7Department of Neurosurgery, Yale School of Medicine, New
Haven, CT, USA. 8Medical Scientist Training Program (MD-PhD), Yale School of Medicine, New Haven, CT, USA. 9Department of Nephrology, Yale School of Medicine, New Haven, CT, USA.
10Department of Pathology, Yale School of Medicine, New Haven, CT, USA. 11Interdisciplinary Center for Bioethics, Yale University, New Haven, CT, USA. 12Vascular Biology and Therapeutics
Program, Yale School of Medicine, New Haven, CT, USA. 13Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA. 14Department of Psychiatry, Yale
School of Medicine, New Haven, CT, USA. 15Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA. 16Program in Cellular Neuroscience, Neurodegeneration and
Repair, Yale School of Medicine, New Haven, CT, USA. 17Yale Child Study Center, New Haven, CT, USA. 18These authors contributed equally: David Andrijevic, Zvonimir Vrselja, Taras Lysyy,
Shupei Zhang. ✉e-mail: nenad.sestan@yale.edu
Content courtesy of Springer Nature, terms of use apply. Rights reserved
... Shortly after death, intracellular acidosis and oedema elicit secondary injury to membranes and organelles, causing an irreversible cascade of apoptosis, necrosis, and axonal damage. This is followed by activation of innate immune responses, leading to endorgan injury and widespread metabolic acidosis [24][25][26][27] , which could alter ADAR and A-to-I editing. Moreover, DNA is relatively stable over extended postmortem periods, RNA is much more chemically labile and sensitive 28 . ...
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... In sum, while NMP allows for prolonged perfusion after extraction, which can buy extra time for liver graft assessment and repair, 49 its medical benefits may not yet quite equal those of NRP, although they may increase as a result of further research on perfusates and biomarkers. 50 Proponents of in situ perfusion, particularly those focused on obtaining hearts, argue that, since TA-NRP is less expensive and resource intensive than NMP, it can be adopted faster and more equitably than NMP. The estimated costs of NMP appear to be higher than those of NRP because NMP requires the purchase and maintenance of a purpose-built machine, whereas NRP uses already purchased ECMO machines and NMP relies more on disposable supplies. ...
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  • Nov 2021
  • NEURON
The hippocampal-entorhinal system supports cognitive functions, has lifelong neurogenic capabilities in many species, and is selectively vulnerable to Alzheimer’s disease. To investigate neurogenic potential and cellular diversity, we profiled single-nucleus transcriptomes in five hippocampal-entorhinal subregions in humans, macaques, and pigs. Integrated cross-species analysis revealed robust transcriptomic and histologic signatures of neurogenesis in the adult mouse, pig, and macaque but not humans. Doublecortin (DCX), a widely accepted marker of newly generated granule cells, was detected in diverse human neurons, but it did not define immature neuron populations. To explore species differences in cellular diversity and implications for disease, we characterized subregion-specific, transcriptomically defined cell types and transitional changes from the three-layered archicortex to the six-layered neocortex. Notably, METTL7B defined subregion-specific excitatory neurons and astrocytes in primates, associated with endoplasmic reticulum and lipid droplet proteins, including Alzheimer’s disease-related proteins. This resource reveals cell-type- and species-specific properties shaping hippocampal-entorhinal neurogenesis and function.
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A systematic review and meta-analyses of regional perfusion in donation after circulatory death solid organ transplantation
Article
Full-text available
  • Sep 2021
  • TRANSPL INT
In donation after circulatory death (DCD), (thoraco)abdominal regional perfusion (RP) restores circulation to a region of the body following death declaration. We systematically reviewed outcomes of solid organ transplantation after RP by searching PubMed, Embase, and Cochrane libraries. Eighty-eight articles reporting on outcomes of liver, kidney, pancreas, heart, and lung transplants or donor/organ utilisation were identified. Meta-analyses were conducted when possible. Methodological quality was assessed using National Institutes of Health (NIH)-scoring tools. Case reports (13/88), case series (44/88), retrospective cohort studies (35/88), retrospective matched cohort studies (5/88), and case-control studies (2/88) were identified, with overall fair quality. As blood viscosity and rheology change below 20°C, studies were grouped as hypothermic (HRP, ≤20°C) or normothermic (NRP, >20°C) regional perfusion. Data demonstrate that RP is a safe alternative to in situ cold preservation (ISP) in uncontrolled and controlled DCDs. The scarce HRP data are from before 2005. NRP appears to reduce post-transplant complications, especially biliary complications in controlled DCD livers, compared to ISP. Comparisons for kidney and pancreas with ISP are needed but there is no evidence NRP is detrimental. Additional data on NRP in thoracic organs are needed. Whether RP increases donor or organ utilisation needs further research.
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Transcriptomic Hallmarks of Ischemia-Reperfusion Injury
Article
Full-text available
  • Jul 2021
Ischemia reperfusion injury (IRI) is associated with a broad array of life-threatening medical conditions including myocardial infarct, cerebral stroke, and organ transplant. Although the pathobiology and clinical manifestations of IRI are well reviewed by previous publications, IRI-related transcriptomic alterations are less studied. This study aimed to reveal a transcriptomic hallmark for IRI by using the RNA-sequencing data provided by several studies on non-human preclinical experimental models. In this regard, we focused on the transcriptional responses of IRI in an acute time-point up to 48 h. We compiled a list of highly reported genes in the current literature that are affected in the context of IRI. We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses and found many of the up-regulated genes to be involved in cell survival, cell surface signaling, response to oxidative stress, and inflammatory response, while down-regulated genes were predominantly involved in ion transport. Furthermore, by GO analysis, we found that multiple inflammatory and stress response processes were affected after IRI. Tumor necrosis factor alpha (TNF) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways were also highlighted in the Kyoto Encyclopedia of Genes and Genomes enrichment analysis. In the last section, we discuss the treatment approaches and their efficacy for IRI by comparing RNA sequencing data from therapeutic interventions with the results of our cross-comparison of differentially expressed genes and pathways across IRI.
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Integrated analysis of multimodal single-cell data
Article
Full-text available
  • May 2021
  • CELL
The simultaneous measurement of multiple modalities represents an exciting frontier for single-cell genomics and necessitates computational methods that can define cellular states based on multimodal data. Here, we introduce “weighted-nearest neighbor” analysis, an unsupervised framework to learn the relative utility of each data type in each cell, enabling an integrative analysis of multiple modalities. We apply our procedure to a CITE-seq dataset of 211,000 human peripheral blood mononuclear cells (PBMCs) with panels extending to 228 antibodies to construct a multimodal reference atlas of the circulating immune system. Multimodal analysis substantially improves our ability to resolve cell states, allowing us to identify and validate previously unreported lymphoid subpopulations. Moreover, we demonstrate how to leverage this reference to rapidly map new datasets and to interpret immune responses to vaccination and coronavirus disease 2019 (COVID-19). Our approach represents a broadly applicable strategy to analyze single-cell multimodal datasets and to look beyond the transcriptome toward a unified and multimodal definition of cellular identity.
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Pyroptosis: mechanisms and diseases
Article
Full-text available
  • Mar 2021
Currently, pyroptosis has received more and more attention because of its association with innate immunity and disease. The research scope of pyroptosis has expanded with the discovery of the gasdermin family. A great deal of evidence shows that pyroptosis can affect the development of tumors. The relationship between pyroptosis and tumors is diverse in different tissues and genetic backgrounds. In this review, we provide basic knowledge of pyroptosis, explain the relationship between pyroptosis and tumors, and focus on the significance of pyroptosis in tumor treatment. In addition, we further summarize the possibility of pyroptosis as a potential tumor treatment strategy and describe the side effects of radiotherapy and chemotherapy caused by pyroptosis. In brief, pyroptosis is a double-edged sword for tumors. The rational use of this dual effect will help us further explore the formation and development of tumors, and provide ideas for patients to develop new drugs based on pyroptosis.
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Inference and analysis of cell-cell communication using CellChat
Article
Full-text available
  • Feb 2021
Understanding global communications among cells requires accurate representation of cell-cell signaling links and effective systems-level analyses of those links. We construct a database of interactions among ligands, receptors and their cofactors that accurately represent known heteromeric molecular complexes. We then develop CellChat, a tool that is able to quantitatively infer and analyze intercellular communication networks from single-cell RNA-sequencing (scRNA-seq) data. CellChat predicts major signaling inputs and outputs for cells and how those cells and signals coordinate for functions using network analysis and pattern recognition approaches. Through manifold learning and quantitative contrasts, CellChat classifies signaling pathways and delineates conserved and context-specific pathways across different datasets. Applying CellChat to mouse and human skin datasets shows its ability to extract complex signaling patterns. Our versatile and easy-to-use toolkit CellChat and a web-based Explorer (http://www.cellchat.org/) will help discover novel intercellular communications and build cell-cell communication atlases in diverse tissues.
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Early United States experience with liver donation after circulatory determination of death using thoraco‐abdominal normothermic regional perfusion: A multi‐institutional observational study
Article
  • Apr 2022
Mortality on the liver waitlist remains unacceptably high. Donation after circulatory determination of death (DCD) donors are considered marginal but are a potentially underutilized resource. Thoraco‐abdominal normothermic perfusion (TA‐NRP) in DCD donors might result in higher quality livers and offset waitlist mortality. We retrospectively reviewed outcomes of the first 13 livers transplanted from TA‐NRP donors in the US. Nine centers transplanted livers from 8 organ procurement organizations. Median donor age was 25 years; median agonal phase was 13 minutes. Median recipient age was 60 years; median lab MELD score was 21. Three patients (23%) met early allograft dysfunction (EAD) criteria. Three received simultaneous liver‐kidney transplants; neither had EAD nor delayed renal allograft function. One recipient died 186 days post‐transplant from sepsis but had normal pre‐sepsis liver function. One patient developed a biliary anastomotic stricture, managed endoscopically; no recipient developed clinical evidence of ischemic cholangiopathy (IC). Twelve of 13 (92%) patients are alive with good liver function at 439 days median follow‐up; 1 patient has extrahepatic recurrent HCC. TA‐NRP DCD livers in these recipients all functioned well, particularly with respect to IC, and provide a valuable option to decrease deaths on the waiting list. This article is protected by copyright. All rights reserved
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Early Experience of Donation After Circulatory Death Heart Transplantation Using Normothermic Regional Perfusion in the United States
Article
  • Sep 2021
  • J THORAC CARDIOV SUR
Objective This pilot study sought to evaluate the feasibility of our donation after circulatory death (DCD) heart transplant protocol using cardiopulmonary bypass (CPB) for normothermic regional reperfusion (NRP). Methods Suitable local DCD candidates were transferred to our institution. Life support was withdrawn in the operating room (OR). Upon declaration of circulatory death, sternotomy was performed and the aortic arch vessels were ligated. CPB was initiated with left ventricular venting. The heart was reperfused with correction of any metabolic abnormalities. CPB was weaned and cardiac function assessed at 30-minute intervals. If accepted, the heart was procured with cold preservation and transplanted into recipients in a nearby OR. Results From January 2020 to January 2021, a total of 8 DCD heart transplants were performed: six isolated hearts, one heart-lung, and one combined heart-kidney. All donor hearts were successfully resuscitated and weaned from CPB without inotropic support. Average lactate and potassium levels decreased from 9.39 ± 1.47 mmol/L to 7.20 ± 0.13 mmol/L and 7.49 ± 1.32 mmol/L to 4.36 ± 0.67 mmol/L, respectively. Post-transplant, the heart-lung recipient required venoarterial extracorporeal membrane oxygenation for primary lung graft dysfunction, but was decannulated on postoperative day 3 and recovered uneventfully. All other recipients required minimal inotropic support without mechanical circulatory support. Survival was 100% with median follow-up of 304 days (interquartile range, 105–371 days). Conclusions DCD heart transplant outcomes have been excellent. Our DCD protocol is adoptable for more widespread use, and will increase donor availability in the United States.
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Brain vulnerability and viability after ischaemia
Article
  • Jul 2021
The susceptibility of the brain to ischaemic injury dramatically limits its viability following interruptions in blood flow. However, data from studies of dissociated cells, tissue specimens, isolated organs and whole bodies have brought into question the temporal limits within which the brain is capable of tolerating prolonged circulatory arrest. This Review assesses cell type-specific mechanisms of global cerebral ischaemia, and examines the circumstances in which the brain exhibits heightened resilience to injury. We suggest strategies for expanding such discoveries to fuel translational research into novel cytoprotective therapies, and describe emerging technologies and experimental concepts. By doing so, we propose a new multimodal framework to investigate brain resuscitation following extended periods of circulatory arrest.
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