normothermic-ex-situ-heart-perfusion-working-mode-assessment-cardiac

Normothermic Ex Situ Heart Perfusion in Working Mode: Assessment of Cardiac Function and Metabolism

The current standard method for organ preservation (cold storage, CS), exposes the heart to a period of cold ischemia that limits the safe preservation ...

normothermic-negative-pressure-ventilation-ex-situ-lung-perfusion

Normothermic Negative Pressure Ventilation <em>Ex Situ</em> Lung Perfusion: Evaluation of Lung Function and Metabolism

Lung transplantation (LTx) remains the standard of care for end-stage lung disease. A shortage of suitable donor organs and concerns over donor organ ...

left-lung-orthotopic-transplantation-juvenile-porcine-model-for

Left Lung Orthotopic Transplantation in a Juvenile Porcine Model for ESLP

Lung transplantation is the gold-standard treatment for end-stage lung disease, with over 4,600 lung transplantations performed worldwide annually. ...

University of Alberta

Normothermic ex vivo lung perfusion (EVLP) allows for assessment and reconditioning of donor lungs. Although a leukocyte filter (LF) is routinely incorporated into the EVLP circuit; its efficacy remains to be determined. Twelve pig lungs were perfused and ventilated ex vivo in a normothermic state for 12 hours. Lungs (n = 3) were allocated to four groups according to perfusate composition and the presence or absence of a LF in the circuit (acellular ± LF, cellular ± LF). Acceptable physiologic lung parameters were achieved during EVLP; however, increased amounts of pro-inflammatory cytokines (TNF-α and IL-6) and leukocytes in the perfusate were observed despite the presence or absence of a LF. Analysis of cells washed off the LF demonstrates that it trapped leukocytes although being ineffective throughout perfusion as it became saturated over 12 hours of EVLP. We conclude that there is no objective evidence to support the routine incorporation of a LF during EVLP as it does not provide further benefit and its removal does not appear to cause harm. The lack of hypothesized benefit to a LF may be because of the saturation of the LF with donor leukocytes, leading to similar amounts of circulating leukocytes still present in the perfusate with and without a LF.

A Leukocyte Filter Does Not Provide Further Benefit During Ex Vivo Lung Perfusion.

Normothermic ex-vivo lung perfusion (EVLP) using positive pressure ventilation (PPV) and both acellular and red blood cell (RBC)-based perfusate solutions have increased the rate of donor organ utilization. We sought to determine whether a negative pressure ventilation (NPV) strategy would improve donor lung assessment during EVLP.

Negative pressure ventilation decreases inflammation and lung edema during normothermic ex-vivo lung perfusion.

Normothermic ex vivo lung perfusion (EVLP) is an evolving technology to evaluate function of donor lungs to determine suitability for transplantation. We hypothesize that hypoxic pulmonary vasoconstriction (HPV) during EVLP will provide a more sensitive parameter of lung function to determine donor lung quality for lung transplantation. Eight porcine lungs were procured, and subsequently underwent EVLP with autologous blood and STEEN solution for 10 h. Standard physiologic parameters including dynamic compliance, peak airway pressure, and pulmonary vascular resistance (PVR) remained stable (P = 0.055), mean oxygenation (PO /FiO ) was 400 ± 18 mm Hg on average throughout perfusion. Response to hypoxia resulted in a robust increase in PVR (ΔPVR) up to 4 h of perfusion, however the HPV response then blunted beyond T6 (P < 0.01). The decrease in HPV response inversely correlated to cytokine concentrations of Interleukin-6 and tumor necrosis factor-α (P < 0.01). Despite acceptable lung oxygenation and standard physiologic parameters during 10 h of EVLP, there is a subclinical deterioration of lung function. HPV challenges can be performed during EVLP as a simple and more sensitive index of pulmonary vascular reactivity.

A Decrease in Hypoxic Pulmonary Vasoconstriction Correlates With Increased Inflammation During Extended Normothermic Ex Vivo Lung Perfusion.

Ex vivo lung perfusion (EVLP) shows promise in ameliorating pretransplant acute lung injury (ALI) and expanding the donor organ pool, but the mechanisms of ex vivo repair remain poorly understood. We aimed to assess the utility of gene expression for characterizing ALI during EVLP. One hundred sixty-nine porcine lung samples were collected in vivo (n = 25), after 0 (n = 11) and 12 (n = 11) hours of cold static preservation (CSP), and after 0 (n = 57), 6 (n = 8), and 12 (n = 57) hours of EVLP, utilizing various ventilation and perfusate strategies. The expression of 53 previously described ALI-related genes was measured and correlated with function and histology. Twenty-eight genes were significantly upregulated and 6 genes downregulated after 12 hours of EVLP. Aggregate gene sets demonstrated differential expression with EVLP (P < .001) but not CSP. Upregulated 28-gene set expression peaked after 6 hours of EVLP, whereas downregulated 6-gene set expression continued to decline after 12 hours. Cellular perfusates demonstrated a greater reduction in downregulated 6-gene set expression vs acellular perfusate (P < .038). Gene set expression correlated with relevant functional and histologic parameters, including P/F ratio (P < .001) and interstitial inflammation (P < .005). Further studies with posttransplant results are warranted to evaluate the clinical significance of this novel molecular approach for assessing organ quality during EVLP.

Ex vivo perfusion induces a time- and perfusate-dependent molecular repair response in explanted porcine lungs.

Myocardial function declines in a time-dependent fashion during ex situ heart perfusion. Cell death and metabolic alterations may contribute to this phenomenon, limiting the safe perfusion period and the potential of ex situ heart perfusion to expand the donor pool. Our aim was to investigate the etiology of myocardial functional decline in ex situ perfused hearts.

Myocardial Functional Decline During Prolonged Ex Situ Heart Perfusion.

Extended periods of ex vivo lung perfusion (EVLP) lead to several inadvertent consequences including accumulation of lactate and increasing electrolyte concentrations in the perfusate. We sought to determine whether continuous hemodialysis (CHD) of the perfusate would be a suitable modality for improving ionic homeostasis in extended EVLP without compromising functional outcomes.

Continuous Hemodialysis Does Not Improve Graft Function During Ex Vivo Lung Perfusion Over 24 Hours.

Ex vivo lung perfusion (EVLP) protocols generally limit metabolic supplementation to insulin and glucose. We sought to determine whether the addition of total parenteral nutrition (TPN) would improve lung function in EVLP. Ten porcine lungs were perfused using EVLP for 24 hours and supplemented with insulin and glucose. In the treatment group (n = 5), the perfusate was also supplemented with a continuous infusion of TPN containing lipids, amino acids, essential vitamins, and cofactors. Physiologic parameters and perfusate electrolytes were continuously evaluated. Perfusate lactate, lipid and branch chain amino acid (BCAA) concentrations were also analyzed to elucidate how substrates were being utilized over time. Lungs in the TPN group exhibited significantly better oxygenation. Perfusate sodium was more stable in the TPN group. In the control group, free fatty acids (FFA) were quickly depleted, reaching negligible levels early in the perfusion. Alternatively, BCAA in the control group rose continually over the perfusion demonstrating a shift toward proteolysis for energy substrate. In the TPN group, both FFA and BCAA concentrations remained stable at in vivo levels after initial stabilization. TNF-α concentrations were lower in the TPN group. The addition of TPN in EVLP allows for better electrolyte composition, decreased inflammation, and improved graft performance.

Total parenteral nutrition in ex vivo lung perfusion: Addressing metabolism improves both inflammation and oxygenation.

Ex situ heart perfusion (ESHP) preserves the donated heart in a perfused, beating condition preventing cold storage-related ischemia and provides a platform to evaluate myocardial viability during preservation. However, myocardial function declines gradually during ESHP. Extracorporeal circulation systems are associated with the induction of systemic inflammatory and stress responses. Our aim was to evaluate the incidence of inflammation and induction of endoplasmic reticulum stress responses during an extended period of ESHP.

Immunity and Stress Responses Are Induced During Ex Situ Heart Perfusion.

Normothermic ex vivo lung perfusion (EVLP) has been used successfully to evaluate and recondition marginal donor lungs; however, multiple barriers continue to prevent its widespread adoption. We sought to develop a common hospital ingredient-derived perfusate (CHIP) with equivalent functional and inflammatory characteristics to a standard Krebs-Henseleit buffer with 8% serum albumin-derived perfusate (KHB-Alb) to improve access and reduce costs of ex vivo organ perfusion.

A Low-Cost Perfusate Alternative for Ex Vivo Lung Perfusion.

Although lung transplant remains the only option for patients with end-stage lung failure, short preservation times result in an inability to meet patient demand. Successful cryopreservation may ameliorate this problem; however, very little research has been performed on lung cryopreservation due to the inability to prevent ice nucleation or growth. Therefore, this research sought to characterize the efficacy of a small-molecule ice recrystallization inhibitor (IRI) for lung cryopreservation given its well-documented ability to control ice growth. Sprague-Dawley heart-lung blocks were perfused at room temperature using a syringe-pump. Cytotoxicity of the IRI was assessed through the subsequent perfusion with 0.4% (w/v) trypan blue followed by formalin-fixation. Ice control was assessed by freezing at a chamber rate of -5 °C/min to -20 °C and cryofixation using a low-temperature fixative. Post-thaw cell survival was determined by freezing at a chamber rate of -5 °C/min to -20 °C and thawing in a 37 °C water bath before formalin-fixation. In all cases, samples were paraffin-embedded, sliced, and stained with eosin. The IRI studied was found to be non-toxic, as cell membrane integrity following perfusion was not significantly different than controls (p = 0.9292). Alveolar ice grain size was significantly reduced by the addition of this IRI (p = 0.0096), and the addition of the IRI to DMSO significantly improved post-thaw cell membrane integrity when compared to controls treated with DMSO alone (p = 0.0034). The techniques described here provide a low-cost solution for rat ex vivo lung perfusion which demonstrated that the ice control and improved post-thaw cell survival afforded by IRI-use warrants further study.

The efficacy of ice recrystallization inhibitors in rat lung cryopreservation using a low cost technique for ex vivo subnormothermic lung perfusion.

Ex situ heart perfusion (ESHP) is being investigated as a method for the continuous preservation of the myocardium in a semiphysiologic state for subsequent transplantation. Most methods of ESHP position the isolated heart in a hanging (H) state, representing a considerable departure from the in vivo anatomical positioning of the heart and may negatively affect the functional preservation of the heart. In the current study, cardiac functional and metabolic parameters were assessed in healthy pig hearts, perfused for 12 hours, in either an H, or supported (S) position, either in nonworking mode (NWM) or working mode (WM). The cardiac function was best preserved in the S position hearts in WM (median 11 hour cardiac index (CI)/1 hour CI%: working mode perfusion in supported position = 94.77% versus nonworking mode perfusion in supported position = 62.80%, working mode perfusion in H position = 36.18%, nonworking mode perfusion in H position = 9.75%; p < 0.001). Delivery of pyruvate bolus significantly improved the function in S groups, however, only partially reversed myocardial dysfunction in the H heart groups. The hearts perfused ex situ in a semianatomical S position and in physiologic WM had better functional preservation and recovery than the H hearts in non-S position. Optimizing the positional support for the ex situ-perfused hearts may improve myocardial preservation during ESHP.

ArticleTotal : 3	Year
Publication title Cited by 22	2019
Publication title	2022
Publication title Cited by 1	2022

Article	Year
A Leukocyte Filter Does Not Provide Further Benefit During Ex Vivo Lung Perfusion. ASAIO journal (American Society for Artificial Internal Organs : 1992)\| PubMed ID: 28234641	2017
Negative pressure ventilation decreases inflammation and lung edema during normothermic ex-vivo lung perfusion. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation\| PubMed ID: 29103845	2018
A Decrease in Hypoxic Pulmonary Vasoconstriction Correlates With Increased Inflammation During Extended Normothermic Ex Vivo Lung Perfusion. Artificial organs\| PubMed ID: 29266272	2018
Ex vivo perfusion induces a time- and perfusate-dependent molecular repair response in explanted porcine lungs. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons\| PubMed ID: 30230229	2018
Myocardial Functional Decline During Prolonged Ex Situ Heart Perfusion. The Annals of thoracic surgery\| PubMed ID: 30872100	2019
Continuous Hemodialysis Does Not Improve Graft Function During Ex Vivo Lung Perfusion Over 24 Hours. Transplantation proceedings\| PubMed ID: 31303418	2019
Total parenteral nutrition in ex vivo lung perfusion: Addressing metabolism improves both inflammation and oxygenation. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons\| PubMed ID: 31420938	2019
Immunity and Stress Responses Are Induced During Ex Situ Heart Perfusion. Circulation. Heart failure\| PubMed ID: 32498623	2020
A Low-Cost Perfusate Alternative for Ex Vivo Lung Perfusion. Transplantation proceedings\| PubMed ID: 32624230	2020
The efficacy of ice recrystallization inhibitors in rat lung cryopreservation using a low cost technique for ex vivo subnormothermic lung perfusion. Cryobiology\| PubMed ID: 33031822	2020
The Position of the Heart During Normothermic Ex Situ Heart Perfusion is an Important Factor in Preservation and Recovery of Myocardial Function. ASAIO journal (American Society for Artificial Internal Organs : 1992)\| PubMed ID: 33741785	2021

Sayed Himmat

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