What’s new in clinical solid organ transplantation by 2013

Role of extracorporeal membrane oxygenation as a salvage therapy for liver transplantation recipients in a high-volume transplant center

Extracorporeal membrane oxygenation (ECMO) has been used sporadically in adult orthotopic liver transplantation (OLT) recipients for the treatment of acute cardiopulmonary failure. This retrospective study aimed to identify OLT patients who would benefit from ECMO support. We reviewed 109 OLT patients who received ECMO support for more than 24 h from January 2007 to December 2020. Among the enrolled patients, 15 (13.8%) experienced 18 ECMO-related complications and 12 (11.0%) experienced ECMO reapplication after weaning during the same hospitalization period. The successful weaning rates were 50.98% in patients who received ECMO support during the peritransplantation period (0-30 days from transplantation) and 51.72% in patients who received ECMO support in the post-OLT period (more than 30 days after OLT); 24 (47.1%) and 23 (39.7%) patients survived until hospital discharge, respectively. The 109 enrolled OLT recipients who received ECMO support during the perioperative period had a 1-year survival rate of 42.6%. Multivariate analyses identified the following as significant and independent risk factors for in-hospital mortality: ECMO treatment prior to 2011 ( p = 0.04), septic shock as the indication for ECMO treatment ( p = 0.001), and a total bilirubin level of ≥5.0 mg/dl ( p = 0.02). The outcomes of adult OLT recipients with ECMO treatment were acceptable in terms of weaning success and survival until hospital discharge. This study confirmed that ECMO treatment for OLT recipients with septic shock and elevated bilirubin levels might be associated with a higher in-hospital mortality and demonstrated the importance of a multidisciplinary ECMO team approach.

Clinical outcomes of immunocompromised patients on extracorporeal membrane oxygenation support for severe acute respiratory failure

OBJECTIVES

There are limited data regarding extracorporeal membrane oxygenation (ECMO) support in immunocompromised patients, despite an increase in ECMO use in patients with respiratory failure. The aim of this study was to investigate the clinical characteristics and outcomes of immunocompromised patients requiring ECMO support for severe acute respiratory failure.

METHODS

Between January 2012 and December 2015, all consecutive adult patients with severe acute respiratory failure who underwent ECMO for respiratory support at 16 tertiary or university-affiliated hospitals in South Korea were enrolled retrospectively. The patients were divided into 2 groups based on the immunocompromised status at the time of ECMO initiation. In-hospital and 6-month mortalities were compared between the 2 groups. In addition, association of immunocompromised status with 6-month mortality was evaluated with logistic regression analysis.

RESULTS

Among 461 patients, 118 (25.6%) were immunocompromised. Immunocompromised patients were younger and had lower haemoglobin and platelet counts than immunocompetent patients. Ventilatory parameters and the use of adjunctive/rescue therapies were similar between the 2 groups, but prone positioning was more commonly used in immunocompetent patients. Successful weaning rates from ECMO (46.6% vs 58.9%; P = 0.021) was lower and hospital mortality (66.1% vs 59.8%; P = 0.22) was higher in immunocompromised patients. In addition, immunocompromised status was associated with higher 6-month mortality (74.6% vs 64.7%, adjusted odds ratio 2.10, 95% confidence interval 1.02-4.35; P = 0.045).

CONCLUSIONS

Immunocompromised patients treated with ECMO support for severe acute respiratory failure had poorer short- and long-term prognoses than did immunocompetent patients.

The impact of systemic innovations for transforming transplant systems. Lessons learned from the German lung transplantation system. A qualitative study

The aim of this paper is to demonstrate the potential of the systemic innovations approach for transforming transplantation systems. It explores potential leverage points for intervening in the LTx-system as well as possible paths of transformation. We present possible transition pathways giving the example of the German Lung transplantation system that teeters on the brink of collapse due to system failures and organ scarcity and illustrate systemic innovations as core mechanisms for systems change in health systems. Desk research and semi-structured experts interviews provided qualitative data for a deductive-inductive coding and a rigorous qualitative content analysis of the data. Depending on the systemic innovations chosen to achieve systems change, transplant systems follow different transformational paths: from a collapse to a leapfrogging towards a non-human transplantation system. Thus, global health areas like transplantation benefit from analysis on systemic innovations as these support researchers, public policy and regulators by developing transformative strategies in healthcare systems.

Expression and Significance of Th17 and Treg Cells in Pulmonary Infections with Gram-Negative Bacteria

The aim of this study was to investigate the expression and significance of T helper type 17 (Th17) and regulatory T (Treg) cells in severe pulmonary infection with gram-negative bacteria (GNB). The peripheral venous blood (PVB) and bronchoalveolar lavage fluid (BALF) were collected from patients receiving mechanical ventilation in the intensive care unit (ICU) owing to: (1) pulmonary GNB infection (group I) and (2) nonpulmonary infection (group NI). Patients from the two groups were matched based on their Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and were recruited in the same period. The levels of Th17 and Treg cells in the PVB and BALF were measured by flow cytometry. (1) The levels of Th17 and Treg cells in the PVB and BALF of the infection group (I) were significantly higher than those of the noninfection group (NI) (p < 0.01), and the levels decreased significantly after treatment (p < 0.01). (2) The Treg/Th17 cell ratio in the PVB and BALF of group I was significantly lower than those of group NI and after treatment (p < 0.01). (3) The levels of Th17 and Treg cells in the PVB and BALF could not predict the 28-day mortality (p > 0.05). The expression of Th17 and Treg cells was abnormal in patients with severe pulmonary GNB infection. Our data suggest an overactive immune response in the early stages of inflammation, but the levels of Treg and Th17 cells failed to predict the 28-day mortality.

High-flow oxygen therapy in immunocompromised patients with acute respiratory failure: A review and meta-analysis

PURPOSE

Acute respiratory failure remains a common hazardous complication in immunocompromised patients and is associated with increased mortality rates when endotracheal intubation is need. We aimed to evaluate the effect of high-flow nasal cannula oxygen therapy (HFNC) compared with other oxygen technique for this patient population.

METHODS

We searched Cochrane library, Embase, PubMed databases before Aug. 15, 2017 for eligible articles. A meta-analysis was performed for measuring short-term mortality (defined as ICU, hospital or 28-days mortality) and intubation rate as the primary outcomes, and length of stay in ICU as the secondary outcome.

RESULTS

We included seven studies involving 667 patients. Use of HFNC was significantly association with a reduction in short-term mortality (RR 0.66; 95% CI, 0.52 to 0.84, p=0.0007) and intubation rate (RR 0.76, 95% CI 0.64 to 0.90; p=0.002). In addition, HFNC did not significant increase length of stay in ICU (MD 0.15days; 95% CI, -2.08 to 2.39; p=0.89).

CONCLUSIONS

The results of current meta-analysis suggest that use of HFNC significantly improve outcomes of acute respiratory failure in immunocompromised patients. Owing to the quality of the included studies, further adequately powered randomized controlled trials are needed to confirm our results.

Efficacy of non-invasive ventilation and oxygen therapy on immunocompromised patients with acute hypoxaemic respiratory failure: protocol for a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

The number of immunocompromised patients has increased in recent years. Acute respiratory failure is a common complication leading to intensive care unit (ICU) admission and high mortality among such patients. The use of non-invasive ventilation (NIV) or oxygen therapy among these patients remains controversial, according to the inconsistent results of several randomised clinical trials (RCTs). This meta-analysis aims to evaluate whether NIV or oxygen therapy is the more appropriate initial oxygenation strategy for the immunocompromised patients with acute respiratory failure.

METHOD

We will search all the RCTs that compared the efficacy of NIV and oxygen therapy on immunocompromised adult patients with acute hypoxaemic respiratory failure on the major databases (Cochrane Library, MEDLINE, EMBASE, Web of Science and others), conference proceedings and grey literature. Eligible RCTs will be included in accordance with the pre-specified eligibility criteria. The risk of bias will be assessed using the Cochrane Collaboration criteria and the quality of evidence will be assessed with the Grading of Recommendations Assessment, Development and Evaluation system. Data will be extracted with a standardised form and analysed using RevMan V.5.3 analyses software. Heterogeneity will be assessed using I² statistic and the source of which will be investigated. Publication bias will be identified with the funnel plot.

ETHICS AND DISSEMINATION

Ethical approval is not required since it is not carried out in humans. The systematic review will be published in peer-reviewed journals and disseminated extensively through conferences.

Use of noninvasive ventilation in immunocompromised patients with acute respiratory failure: a systematic review and meta-analysis

Background

Acute respiratory failure (ARF) remains a common hazardous complication in immunocompromised patients and is associated with increased mortality rates when endotracheal intubation is needed. We aimed to evaluate the effect of early noninvasive ventilation (NIV) compared with oxygen therapy alone in this patient population.

Methods

We searched for relevant studies in MEDLINE, EMBASE, and the Cochrane database up to 25 July 2016. Randomized controlled trials (RCTs) were included if they reported data on any of the predefined outcomes in immunocompromised patients managed with NIV or oxygen therapy alone. Results were expressed as risk ratio (RR) and mean difference (MD) with accompanying 95% confidence interval (CI).

Results

Five RCTs with 592 patients were included. Early NIV significantly reduced short-term mortality (RR 0.62, 95% CI 0.40 to 0.97, p = 0.04) and intubation rate (RR 0.52, 95% CI 0.32 to 0.85, p = 0.01) when compared with oxygen therapy alone, with significant heterogeneity in these two outcomes between the pooled studies. In addition, early NIV was associated with a shorter length of ICU stay (MD −1.71 days, 95% CI −2.98 to 1.44, p = 0.008) but not long-term mortality (RR 0.92, 95% CI 0.74 to 1.15, p = 0.46).

Conclusions

The limited evidence indicates that early use of NIV could reduce short-term mortality in selected immunocompromised patients with ARF. Further studies are needed to identify in which selected patients NIV could be more beneficial, before wider application of this ventilator strategy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1586-9) contains supplementary material, which is available to authorized users.

A Novel and Sensitive Approach for the Evaluation of Liver Ischemia-Reperfusion Injury After Liver Transplantation

OBJECTIVES

The purpose of our study was to evaluate the potential of x-ray propagation-based phase-contrast imaging (PCI) computed tomography (CT) for the detection and characterization of early changes after ischemia-reperfusion (IR) in a standardized rat liver transplantation (LTx) model.

MATERIALS AND METHODS

Syngeneic orthotopic liver transplantation was performed in male Lewis rats. Ischemia-reperfusion injury (IRI)-induced changes of liver parenchyma were investigated in a time-dependent manner (2, 16, 24, and 32 hours). X-ray phase-contrast images of formalin-fixated liver specimens were acquired in CT mode by using a voxel size of 8 × 8 × 8 μm. Necrapoptotic cell death was visualized with the TdT-mediated dUTP-biotin nick end labeling technique, and alterations of liver graft microhemodynamics, that is, acinar and sinusoidal perfusion failure, were evaluated by in vivo fluorescence microscopy.

RESULTS

Acquired and reconstructed PCI-CT images showed an increase in necrotic liver parenchyma dependent on cold storage time, measuring 5.7% ± 1.6% after 2 hours (comparable to 2.6% ± 0.4% for sham livers), 11.5% ± 2.1% (16 hours; P < 0.05 vs control), 23.0% ± 0.5% (24 hours; P < 0.001 vs control), and 31.3% ± 2.2% (32 hours; P < 0.001 vs control). There were a significant lower number of perfused acini in dependence on increasing cold storage time. The acinar perfusion index reached 0.970 ± 0.006 after 2 hours of cold ischemia (comparable to 0.960 ± 0.009 for sham livers) and declined continuously after 16, 24, and 32 hours cold ischemia (0.58 ± 0.03, 0.49 ± 0.02, 0.41 ± 0.03, each P < 0.0001 vs controls). Comparable results were found for sinusoidal perfusion, reaching 1.8% ± 0.4% of nonperfused sinusoids for 2 hours of cold ischemia and 8.2% ± 0.8% after 16 hours, 18.8% ± 1.4% after 24 hours, and 39.0% ± 2.4% after 32 hours (each P < 0.0001 vs controls). Prolonged cold ischemia was associated with an increasing number of TdT-mediated dUTP-biotin nick end labeling-positive cells (hepatocytes and sinusoidal lining cells), reaching 0.4 ± 0.1 (sham), 0.7 ± 0.4 (2 hours), 6.4 ± 1.1 (16 hours), 2.1 ± 0.3 (24 hours), and 14.7 ± 3.5 (32 hours; P = 0.002) for hepatocytes.

CONCLUSIONS

X-ray PCI of histological liver specimens can detect IR-induced tissue necrosis and can provide detailed complementary 3-dimensional information to standard histopathologic findings.

Low level of MAp44, an inhibitor of the lectin complement pathway, and long-term graft and patient survival; a cohort study of 382 kidney recipients

Background

Higher incidence of malignancy and infectious diseases in kidney transplant recipients is related to immunosuppressive treatment after transplantation and the recipient’s native immune system. The complement system is an essential component of the innate immunity. The aim of the present study was to investigate the association of effector molecules of the lectin complement pathway with graft and patient survival after kidney transplantation.

Methods

Two mannan-binding lectin (MBL) associated proteases, MASP-2 and MASP-3 (activators of the lectin pathway) and two MBL-associated proteins, MAp44 and MAp19 (inhibitors of the lectin pathway) were measured at the time of transplantation in 382 patients (≥17 years old) transplanted in 2000–2001. The cohort was followed until December 31, 2014. Data on patient and graft survival were obtained from the Norwegian Renal Registry. Cox proportional hazard regression models were performed for survival analyses.

Results

Low MAp44 level (1st versus 2–4 quartile) was significantly associated with overall mortality; HR 1.52, 95 % CI 1.08–2.14, p = 0.017. In the sub analyses in groups below and above median age (51.7 years), low MAp44 as a predictor of overall mortality was statistically significant only in recipients of ≤51.7 years; HR 2.57, 95 % CI 1.42–4.66, p = 0.002. Furthermore, low MAp44 was associated with mortality due to infectious diseases; HR 2.22, 95 % CI 1.11–4.41, p = 0.023. There was no association between MASP-2, MASP-3 or MAp19 levels and patient mortality. No association between any measured biomarkers and death censored graft loss was found.

Conclusions

Low MAp44 level at the time of transplantation was associated with increased overall mortality in kidney recipients of median age of 51.7 years or below and with mortality due to infectious diseases in the whole patient cohort after nearly 14-years of follow up after transplantation. No associations between other effector molecules; MASP-2, MASP-3 or MAp19 and recipient mortality were found, as well as no association of any biomarker with death censored graft loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0373-9) contains supplementary material, which is available to authorized users.

Comparison of Aerobic Preservation by Venous Systemic Oxygen Persufflation or Oxygenated Machine Perfusion of Warm-Ischemia-Damaged Porcine Kidneys

Background/Aim: The global shortage of donor organs for transplantation has necessitated the expansion of the organ pool through increased use of organs from less ideal donors. Venous systemic oxygen persufflation (VSOP) and oxygenated machine perfusion (OMP) have previously demonstrated beneficial results compared to cold storage (CS) in the preservation of warm-ischemia-damaged kidney grafts. The aim of this study was to compare the efficacy of VSOP and OMP for the preservation of warm-ischemia-damaged porcine kidneys using the recently introduced Ecosol preservation solution compared to CS using Ecosol or histidine-tryptophan-ketoglutarate solution (HTK). Materials and Methods: Kidneys from German Landrace pigs (n = 5/group) were retrieved and washed out with either Ecosol or HTK after 45 min of clamping of the renal pedicle. As controls, kidneys without warm ischemia, cold stored for 24 h in HTK, were employed. Following 24 h of preservation by VSOP, OMP, CS-Ecosol, or CS-HTK, renal function and damage were assessed during 1 h using the isolated perfused porcine kidney model. Results: During reperfusion, urine production was significantly higher in the VSOP and OMP groups than in the CS-HTK group; however, only VSOP could demonstrate lower urine protein concentrations and fractional excretion of sodium, which did not differ from the non-warm-ischemia-damaged control group. VSOP, CS-Ecosol, and controls showed better maintenance of the acid-base balance than CS-HTK. Reduced lipid peroxidation, as reflected in postreperfusion tissue thiobarbituric acid-reactive substance levels, was observed in the VSOP group compared to the OMP group, and the VSOP and CS-Ecosol groups had concentrations similar to the controls. The ratio of reduced to oxidized glutathione was higher in the VSOP, OMP, and CS-Ecosol groups than in the CS-HTK group and controls, with a higher ratio in the VSOP than in the OMP group. Conclusion: VSOP was associated with mitigation of oxidative stress in comparison to OMP and CS. Preservation of warm-ischemia-damaged porcine kidneys by VSOP was improved compared to OMP and CS, and was comparable to preservation of non-warm-ischemia-damaged cold-stored kidneys.

Kupffer cells and liver transplantation

Nowadays, liver transplantation is globally considered the most effective treatment for end-stage liver diseases. Ischemia-reperfusion (I/R) injury and immune rejection response (IRR) are the two major imperfections which severely affect the recipients' prognosis and survival rate without satisfactory clinical management strategies. Therefore, exploring effective methods to improve I/R injury and IRR have important clinical significance under circumstances of shortage of donor livers. Kupffer cells (KCs) are the largest population of antigen representing cells (APCs) which settle in the liver. As the first defensive line of the live, KCs exhibit various biological effects. However, the exact mechanisms responsible for the role of KCs in I/R injury and IRR remain elusive. We hereby review the current finding about the role of KCs in I/R injury and IRR.