Publications by authors named "Benjamin Adam"

29 Publications

  • Page 1 of 1

Fatigability of the External Anal Sphincter Muscles Using a Novel Strength Training Resistance Exercise Device.

Am J Physiol Gastrointest Liver Physiol 2021 Feb 17. Epub 2021 Feb 17.

Division of Gastroenterology & Hepatology, Medical College of Wisconsin, United States.

Introduction: Exercises involving pelvic floor muscles including repetitive voluntary contractions of external anal sphincter (EAS) musculature have been used to improve fecal incontinence. Muscle fatigue is a prerequisite for successful strength training. However, muscle fatigue induced by these exercises has not been systematically studied. We aimed to assess the fatigability of EAS muscles during various exercise methods.

Methods: Twelve nulliparous (21 ± 2.7 yrs.) females were studied. We evaluated fatigue during 40 repetitive 3 sec contractions and 30 sec long squeeze contractions both with and without an intra-anal compressible resistant load. The sequence of exercises was randomized. This load was provided by the continence muscles Resistance Exerciser Device. Anal canal pressures were recorded by high-resolution manometry.

Results: Exercise against a resistive load showed significant decrease in anal contractile integral (CI) and maximum squeeze pressure during repetitive short squeeze contractions compared to exercise without a load. Linear regression analysis showed a significant negative correlation between anal CI and successive contraction against load, suggesting "fatigue". Similar findings were observed for maximum squeeze pressure (slope with load -4.2, P=0.0003 vs without load -0.9, P=0.3). Long squeeze contraction against a load was also more susceptible to fatigue than without a load (p<0.0001).

Conclusions: Repetitive contractions against a compressible load induces fatigue and thus has the potential to strengthen the anal sphincter contractile function than contractions without a load. Fatigue rate in long squeeze contraction exercises with a load is significantly faster than that without a load also indicating greater effectiveness in inducing muscle fatigue.
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http://dx.doi.org/10.1152/ajpgi.00456.2020DOI Listing
February 2021

Structural Valve Deterioration Is Linked to Increased Immune Infiltrate and Chemokine Expression.

J Cardiovasc Transl Res 2020 Oct 21. Epub 2020 Oct 21.

Division of Cardiac Surgery, Department of Surgery, University of Alberta, Edmonton, AB, T6G 2R3, Canada.

We aim to investigate whether structural valve deterioration (SVD) of bioprosthetic xenogenic tissue heart valves (XTHVs) is associated with increased immune cell infiltration and whether co-expression of several chemokines correlates with this increase in immune infiltrate. Explanted XTHVs from patients undergoing redo valve replacement for SVD were obtained. Immunohistochemical, microscopic, and gene expression analysis approaches were used. XTHVs (n = 37) were obtained from 32 patients (mean 67.7 years) after a mean time of 11.6 years post-implantation. Significantly increased immune cellular infiltration was observed in the explanted SVD valves for all immune cell types examined, including T cells, macrophages, B cells, neutrophils, and plasma cells, compared to non-SVD controls. Furthermore, a significantly increased chemokine gradient in explanted SVD valves accompanied immune cell infiltration. These data suggest the development of SVD is associated with a significantly increased burden of immune cellular infiltrate correlated to the induction of a chemokine gradient around the XHTV, representing chronic immune rejection.Graphical abstract Proposed interaction between innate and adaptive immunity leading to the development of structural valve deterioration in xenogenic tissue heart valves.
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http://dx.doi.org/10.1007/s12265-020-10080-xDOI Listing
October 2020

IgE in Antibody-Mediated Rejection: A Novel Pathogenic Mechanism?

Clin J Am Soc Nephrol 2020 Oct 9;15(10):1392-1393. Epub 2020 Sep 9.

Department of Pathology, Emory University, Atlanta, Georgia

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http://dx.doi.org/10.2215/CJN.13000820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7536743PMC
October 2020

Borrowing from the past to invest in the future: The AJT editorial fellowship process.

Am J Transplant 2021 Mar 22;21(3):1343-1344. Epub 2020 Sep 22.

Department of Pathology, Emory University, Atlanta, Georgia, USA.

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http://dx.doi.org/10.1111/ajt.16306DOI Listing
March 2021

Molecular assessment of antibody-mediated rejection in human pancreas allograft biopsies.

Clin Transplant 2020 Nov 30;34(11):e14065. Epub 2020 Aug 30.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.

Pancreas transplant longevity is limited by immune rejection, which is diagnosed by graft biopsy using the Banff Classification. The histological criteria for antibody-mediated rejection (AMR) are poorly reproducible and inconsistently associated with outcome. We hypothesized that a 34-gene set associated with antibody-mediated rejection in other solid organ transplants could improve diagnosis in pancreas grafts. The AMR 34-gene set, comprising endothelial, natural killer cell and inflammatory genes, was quantified using the NanoString platform in 52 formalin-fixed, paraffin-embedded pancreas transplant biopsies from 41 patients: 15 with pure AMR or mixed rejection, 22 with T cell-mediated rejection/borderline and 15 without rejection. The AMR 34-gene set was significantly increased in pure AMR and mixed rejection (P = .001) vs no rejection. The gene set predicted histological AMR with an area under the receiver operating characteristic curve (ROC AUC) of 0.714 (P = .004). The AMR 34-gene set was the only biopsy feature significantly predictive of allograft failure in univariate analysis (P = .048). Adding gene expression to DSA and histology increased ROC AUC for the prediction of failure from 0.736 to 0.770, but this difference did not meet statistical significance. In conclusion, assessment of transcripts has the potential to improve diagnosis and outcome prediction in pancreas graft biopsies.
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http://dx.doi.org/10.1111/ctr.14065DOI Listing
November 2020

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

Transplant Proc 2020 Dec 2;52(10):2941-2946. Epub 2020 Jul 2.

Division of Cardiac Surgery, Department of Surgery, University of Alberta, Edmonton, AB, Canada; Mazankowski Alberta Heart Institute, Edmonton, AB, Canada; Alberta Transplant Institute, Edmonton, AB, Canada; Canadian National Transplant Research Program, Edmonton, AB, Canada. Electronic address:

Background: 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.

Methods: Sixteen porcine lungs were perfused using negative pressure ventilation (NPV) EVLP for 12 hours in a normothermic state and were allocated equally to 2 groups: KHB-Alb vs CHIP. Physiological parameters, cytokine profiles, and edema formation were compared between treatment groups.

Results: Perfused lungs in both groups demonstrated equivalent oxygenation (partial pressure of arterial oxygen/fraction of inspired oxygen ratio >350 mm Hg) and physiological parameters. There was equivalent generation of tumor necrosis factor-α and IL-6, irrespective of perfusate solution used, when comparing CHIP vs KHB-Alb. Pig lungs developed equivalent edema formation between groups (CHIP: 15.8 ± 4.8%, KHB-Alb 19.5 ± 4.4%, P > .05).

Conclusion: A perfusate derived of common hospital ingredients provides equivalent results to a standard Krebs-Henseleit buffer with 8% serum albumin-based perfusate in NPV-EVLP.
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http://dx.doi.org/10.1016/j.transproceed.2020.05.007DOI Listing
December 2020

Disease recurrence after lung transplantation for idiopathic pulmonary hemosiderosis.

Respir Med Case Rep 2020 10;30:101128. Epub 2020 Jun 10.

Department of Medicine, University of Alberta, Edmonton, Canada.

Idiopathic pulmonary hemosiderosis is characterized by the triad of hemoptysis, iron deficiency anemia and pulmonary infiltrates. Though idiopathic pulmonary hemosiderosis has classically been described as a childhood disease, survival into adulthood is possible. Treatment options for advanced and/or refractory disease is limited, and in our unique case of idiopathic pulmonary hemosiderosis with precapillary pulmonary hypertension, lung transplantation has had a favorable short-term outcome. We also demonstrate that disease recurrence of idiopathic pulmonary hemosiderosis following lung transplantation is possible.
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http://dx.doi.org/10.1016/j.rmcr.2020.101128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305376PMC
June 2020

The XVth Banff Conference on Allograft Pathology the Banff Workshop Heart Report: Improving the diagnostic yield from endomyocardial biopsies and Quilty effect revisited.

Am J Transplant 2020 12 28;20(12):3308-3318. Epub 2020 Jun 28.

Department of Pathology, Stanford University, Stanford, California, USA.

The XVth Banff Conference on Allograft Pathology meeting was held on September 23-27, 2019, in Pittsburgh, Pennsylvania, USA. During this meeting, two main topics in cardiac transplant pathology were addressed: (a) Improvement of endomyocardial biopsy (EMB) accuracy for the diagnosis of rejection and other significant injury patterns, and (b) the orphaned lesion known as Quilty effect or nodular endocardial infiltrates. Molecular technologies have evolved in recent years, deciphering pathophysiology of cardiac rejection. Diagnostically, it is time to integrate the histopathology of EMBs and molecular data. The goal is to incorporate molecular pathology, performed on the same paraffin block as a companion test for histopathology, to yield more accurate and objective EMB interpretation. Application of digital image analysis from hematoxylin and eosin (H&E) stain to multiplex labeling is another means of extracting additional information from EMBs. New concepts have emerged exploring the multifaceted significance of myocardial injury, minimal rejection patterns supported by molecular profiles, and lesions of arteriolitis/vasculitis in the setting of T cell-mediated rejection (TCMR) and antibody-mediated rejection (AMR). The orphaned lesion known as Quilty effect or nodular endocardial infiltrates. A state-of-the-art session with historical aspects and current dilemmas was reviewed, and possible pathogenesis proposed, based on advances in immunology to explain conflicting data. The Quilty effect will be the subject of a multicenter project to explore whether it functions as a tertiary lymphoid organ.
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http://dx.doi.org/10.1111/ajt.16083DOI Listing
December 2020

The Banff 2019 Kidney Meeting Report (I): Updates on and clarification of criteria for T cell- and antibody-mediated rejection.

Am J Transplant 2020 09 28;20(9):2318-2331. Epub 2020 May 28.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.

The XV. Banff conference for allograft pathology was held in conjunction with the annual meeting of the American Society for Histocompatibility and Immunogenetics in Pittsburgh, PA (USA) and focused on refining recent updates to the classification, advances from the Banff working groups, and standardization of molecular diagnostics. This report on kidney transplant pathology details clarifications and refinements to the criteria for chronic active (CA) T cell-mediated rejection (TCMR), borderline, and antibody-mediated rejection (ABMR). The main focus of kidney sessions was on how to address biopsies meeting criteria for CA TCMR plus borderline or acute TCMR. Recent studies on the clinical impact of borderline infiltrates were also presented to clarify whether the threshold for interstitial inflammation in diagnosis of borderline should be i0 or i1. Sessions on ABMR focused on biopsies showing microvascular inflammation in the absence of C4d staining or detectable donor-specific antibodies; the potential value of molecular diagnostics in such cases and recommendations for use of the latter in the setting of solid organ transplantation are presented in the accompanying meeting report. Finally, several speakers discussed the capabilities of artificial intelligence and the potential for use of machine learning algorithms in diagnosis and personalized therapeutics in solid organ transplantation.
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http://dx.doi.org/10.1111/ajt.15898DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496245PMC
September 2020

Banff 2019 Meeting Report: Molecular diagnostics in solid organ transplantation-Consensus for the Banff Human Organ Transplant (B-HOT) gene panel and open source multicenter validation.

Am J Transplant 2020 09 27;20(9):2305-2317. Epub 2020 Jun 27.

Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.

This meeting report from the XV Banff conference describes the creation of a multiorgan transplant gene panel by the Banff Molecular Diagnostics Working Group (MDWG). This Banff Human Organ Transplant (B-HOT) panel is the culmination of previous work by the MDWG to identify a broadly useful gene panel based on whole transcriptome technology. A data-driven process distilled a gene list from peer-reviewed comprehensive microarray studies that discovered and validated their use in kidney, liver, heart, and lung transplant biopsies. These were supplemented by genes that define relevant cellular pathways and cell types plus 12 reference genes used for normalization. The 770 gene B-HOT panel includes the most pertinent genes related to rejection, tolerance, viral infections, and innate and adaptive immune responses. This commercially available panel uses the NanoString platform, which can quantitate transcripts from formalin-fixed paraffin-embedded samples. The B-HOT panel will facilitate multicenter collaborative clinical research using archival samples and permit the development of an open source large database of standardized analyses, thereby expediting clinical validation studies. The MDWG believes that a pathogenesis and pathway based molecular approach will be valuable for investigators and promote therapeutic decision-making and clinical trials.
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http://dx.doi.org/10.1111/ajt.16059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496585PMC
September 2020

Intragraft gene expression in native kidney BK virus nephropathy versus T cell-mediated rejection: Prospects for molecular diagnosis and risk prediction.

Am J Transplant 2020 12 29;20(12):3486-3501. Epub 2020 May 29.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.

Novel tools are needed to improve diagnostic accuracy and risk prediction in BK virus nephropathy (BKVN). We assessed the utility of intragraft gene expression testing for these purposes. Eight hundred genes were measured in 110 archival samples, including a discovery cohort of native kidney BKVN (n = 5) vs pure T cell-mediated rejection (TCMR; n = 10). Five polyomavirus genes and seven immune-related genes (five associated with BKVN and two associated with TCMR) were significantly differentially expressed between these entities (FDR < 0.05). These three sets of genes were further evaluated in samples representing a spectrum of BK infection (n = 25), followed by a multicenter validation cohort of allograft BKVN (n = 60) vs TCMR (n = 10). Polyomavirus 5-gene set expression reliably distinguished BKVN from TCMR (validation cohort AUC = 0.992), but the immune gene sets demonstrated suboptimal diagnostic performance (AUC ≤ 0.720). Within the validation cohort, no significant differences in index biopsy gene expression were identified between BKVN patients demonstrating resolution (n = 35), persistent infection (n = 14) or de novo rejection (n = 11) 6 months following a standardized reduction in immunosuppression. These results suggest that, while intragraft polyomavirus gene expression may be useful as an ancillary diagnostic for BKVN, assessment for concurrent TCMR and prediction of clinical outcome may not be feasible with current molecular tools.
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http://dx.doi.org/10.1111/ajt.15980DOI Listing
December 2020

Clinicopathologic predictors of renal outcomes in light chain cast nephropathy: a multicenter retrospective study.

Blood 2020 05;135(21):1833-1846

Department of Nephrology and Renal Transplantation, CIC INSERM 1402, Centre Hospitalier Universitaire, Université de Poitiers, Poitiers, CNRS UMR 7276, Limoges, and French Reference Centre for AL Amyloidosis, Poitiers, France.

Light chain cast nephropathy (LCCN) in multiple myeloma often leads to severe and poorly reversible acute kidney injury. Severe renal impairment influences the allocation of chemotherapy and its tolerability; it also affects patient survival. Whether renal biopsy findings add to the clinical assessment in predicting renal and patient outcomes in LCCN is uncertain. We retrospectively reviewed clinical presentation, chemotherapy regimens, hematologic response, and renal and patient outcomes in 178 patients with biopsy-proven LCCN from 10 centers in Europe and North America. A detailed pathology review, including assessment of the extent of cast formation, was performed to study correlations with initial presentation and outcomes. Patients presented with a mean estimated glomerular filtration rate (eGFR) of 13 ± 11 mL/min/1.73 m2, and 82% had stage 3 acute kidney injury. The mean number of casts was 3.2/mm2 in the cortex. Tubulointerstitial lesions were frequent: acute tubular injury (94%), tubulitis (82%), tubular rupture (62%), giant cell reaction (60%), and cortical and medullary inflammation (95% and 75%, respectively). Medullary inflammation, giant cell reaction, and the extent of cast formation correlated with eGFR value at LCCN diagnosis. During a median follow-up of 22 months, mean eGFR increased to 43 ± 30 mL/min/1.73 m2. Age, β2-microglobulin, best hematologic response, number of cortical casts per square millimeter, and degree of interstitial fibrosis/tubular atrophy (IFTA) were independently associated with a higher eGFR during follow-up. This eGFR value correlated with overall survival, independently of the hematologic response. This study shows that extent of cast formation and IFTA in LCCN predicts the quality of renal response, which, in turn, is associated with overall survival.
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http://dx.doi.org/10.1182/blood.2019003807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243151PMC
May 2020

Hot deformation data for Haynes 214, Haynes 230 and Inconel 740H.

Data Brief 2020 Feb 12;28:104923. Epub 2019 Dec 12.

Department of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, OR, 97331, USA.

This article presents the datasets gathered for the hot processing of three Ni-based superalloys intended for A-USC application, Haynes 214, Haynes 230 and Inconel 740H. Isothermal compression tests were conducted with a Gleeble 3500 at temperatures between 1000 °C and 1200 °C and strain rates between 0.01/s and 1/s to a full true strain of 0.7. The obtained true stress-true strain curves were used as basis for hot processing maps, linking temperature, stress and strain rate. Subsequently, all samples were sectioned through the geometric centre to provide microstructural information, captured using EBSD, as well as EDX for the evolution of secondary phases. Thermodynamic modelling was performed to validate compositions and mass fraction data from EDX measurements. These combined datasets help in understanding the deformation behaviour of a selected range of superalloys, under commercial processing conditions, aiding in process design optimizations and improvements. For complete interpretation of the data the reader should refer to the related publication "Comparative study of the hot processing behavior in advanced Ni-based superalloys for use in A-USC applications".
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http://dx.doi.org/10.1016/j.dib.2019.104923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6931106PMC
February 2020

Apelin directs endothelial cell differentiation and vascular repair following immune-mediated injury.

J Clin Invest 2020 01;130(1):94-107

Department of Medicine.

Sustained, indolent immune injury of the vasculature of a heart transplant limits long-term graft and recipient survival. This injury is mitigated by a poorly characterized, maladaptive repair response. Vascular endothelial cells respond to proangiogenic cues in the embryo by differentiation to specialized phenotypes, associated with expression of apelin. In the adult, the role of developmental proangiogenic cues in repair of the established vasculature is largely unknown. We found that human and minor histocompatibility-mismatched donor mouse heart allografts with alloimmune-mediated vasculopathy upregulated expression of apelin in arteries and myocardial microvessels. In vivo, loss of donor heart expression of apelin facilitated graft immune cell infiltration, blunted vascular repair, and worsened occlusive vasculopathy in mice. In vitro, an apelin receptor agonist analog elicited endothelial nitric oxide synthase activation to promote endothelial monolayer wound repair and reduce immune cell adhesion. Thus, apelin acted as an autocrine growth cue to sustain vascular repair and mitigate the effects of immune injury. Treatment with an apelin receptor agonist after vasculopathy was established markedly reduced progression of arterial occlusion in mice. Together, these initial data identify proangiogenic apelin as a key mediator of coronary vascular repair and a pharmacotherapeutic target for immune-mediated injury of the coronary vasculature.
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http://dx.doi.org/10.1172/JCI128469DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934203PMC
January 2020

Long-term Kinetics of Intragraft Gene Signatures in Renal Allograft Tolerance Induced by Transient Mixed Chimerism.

Transplantation 2019 11;103(11):e334-e344

Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA.

Background: Renal allograft tolerance (TOL) has been successfully induced in nonhuman primates (NHPs) and humans through the induction of transient mixed chimerism. To elucidate the mechanisms of TOL, we compared local immunologic responses in renal allografts with those in T-cell-mediated rejection (TCMR) and chronic antibody-mediated rejection (CAMR) in NHPs.

Methods: Using the NanoString nCounter platform, we retrospectively studied 52 mRNAs in 256 kidney allograft samples taken from NHP kidney recipients of donor BMT. No immunosuppression was given after 1-month post-donor BMT. Recipients who achieved TOL (n = 13) survived for >1840 ± 1724 days with normal kidney function, while recipients with CAMR (n = 13) survived for 899 ± 550 days with compromised graft function, and recipients with TCMR (n = 15) achieved only short-term survival (132 ± 69 days).

Results: The most prominent difference between the groups was FOXP3, which was significantly higher in TOL than in CAMR and TCMR, both early (<1 y, P < 0.01) and late (≥1 y, P < 0.05) after transplant. Other mRNAs related to regulatory T cells (Treg), such as IL10, TGFB, and GATA3, were also high in TOL. In contrast, transcripts of inflammatory cytokines were higher in TCMR, while activated endothelium-associated transcripts were higher in CAMR than in TOL. The receiver operating characteristic analyses revealed that intragraft FOXP3 and CAV1 can reliably distinguish TOL from CAMR.

Conclusions: High FOXP3 and other Treg-related mRNAs together with suppressed inflammatory responses and endothelial activation in renal allografts suggest that intragraft enrichment of Treg is a critical mechanism of renal allograft TOL induced by transient mixed chimerism.
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http://dx.doi.org/10.1097/TP.0000000000002911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6814550PMC
November 2019

Avoiding initial hypothermia does not improve liver graft quality in a porcine donation after circulatory death (DCD) model of normothermic perfusion.

PLoS One 2019 6;14(8):e0220786. Epub 2019 Aug 6.

Department of Surgery, Division of General Surgery, University of Alberta, Edmonton AB, Canada.

Background: Normothermic machine perfusion (NMP) of liver grafts donated after circulatory death (DCD) has shown promise in large animal and clinical trials. Following procurement, initial flush with a cold preservation solution is the standard of care. There is concern that initial cooling followed by warming may exacerbate liver injury, and the optimal initial flush temperature has yet to be identified. We hypothesize that avoidance of the initial cold flush will yield better quality liver grafts.

Methods: Twenty-four anaesthetized pigs were withdrawn from mechanical ventilation and allowed to arrest. After 60-minutes of warm ischemia to simulate a DCD procurement, livers were flushed with histidine-tryptophan-ketoglutarate (HTK) at 4°C, 25°C or 35°C (n = 4 per group). For comparison, an adenosine-lidocaine crystalloid solution (AD), shown to have benefit at warm temperatures in heart perfusions, was also used (n = 4 per group). During 12-hours of NMP, adenosine triphosphate (ATP), lactate, transaminase levels, and histological injury were determined. Bile production and hemodynamics were monitored continuously.

Results: ATP levels recovered substantially following 1-hour of NMP reaching pre-ischemic levels by the end of NMP with no difference between groups. There was no difference in peak aspartate aminotransferase (AST) or in lactate dehydrogenase (LDH). Portal vein resistance was lowest in the 4°C group reaching significance after 2 hours (0.13 CI -0.01,0.277, p = 0.025). Lactate levels recovered promptly with no difference between groups. Comparison to AD groups showed no statistical difference in the abovementioned parameters. On electron microscopy the HTK4°C group had the least edema with mean cell thickness of 2.92μm (p = 0.41) while also having the least sinusoidal dilatation with a mean diameter of 5.36μm (p = 0.04). For AD, the 25°C group had the lowest mean cell thickness at 3.14μm (p = 0.09).

Conclusions: Avoidance of the initial cold flush failed to demonstrate added benefit over standard 4°C HTK in this DCD model of liver perfusion.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220786PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6684160PMC
March 2020

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

Transplant Proc 2019 Jul - Aug;51(6):2022-2028. Epub 2019 Jul 11.

Division of Cardiac Surgery, Department of Surgery, University of Alberta, Edmonton, AB, Canada; Mazankowski Alberta Heart Institute, Edmonton, AB, Canada; Alberta Transplant Institute, Edmonton, AB, Canada; Canadian National Transplant Research Program, Edmonton, AB, Canada. Electronic address:

Background: 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.

Methods: Twelve porcine lungs were perfused using EVLP for 24 hours. All lungs were ventilated with negative pressure ventilation. Lungs in the treatment group (n = 6) underwent continuous hemodialysis of the perfusate. Functional parameters, edema formation, and histopathologic analysis were used to assess graft function. Electrolyte and lactate profiles were also followed to assess the efficiency of hemodialysis.

Results: Lungs in both treatment and control groups demonstrated stable and acceptable oxygenation to 24 hours. Lungs demonstrated a decrease in compliance over time. There was no difference in oxygenation and compliance between groups. CHD-EVLP lungs had higher pulmonary vascular resistance and pulmonary artery pressures. Despite increased perfusion pressures, weight gain at both 11 and 23 hours was not different between groups. Perfusate sodium and lactate concentrations were significantly lower in the CHD-EVLP group.

Conclusion: The addition of continuous hemodialysis to EVLP did not improve graft function up to 24 hours despite improved maintenance of perfusate composition.
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http://dx.doi.org/10.1016/j.transproceed.2019.03.042DOI Listing
November 2019

Mycobacterium chimaera Encephalitis Following Cardiac Surgery: A New Syndrome.

Clin Infect Dis 2020 02;70(4):692-695

Division of Infectious Diseases, University of Alberta, Edmonton, Canada.

We report the cases of 3 patients with fatal, disseminated Mycobacterium chimaera infections following cardiac surgeries. Progressive neurocognitive decline and death were explained by active granulomatous encephalitis, with widespread involvement of other organs. This syndrome is clinically elusive and, thus, may have caused deaths in prior reported series.
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http://dx.doi.org/10.1093/cid/ciz497DOI Listing
February 2020

Enteromius pinnimaculatus sp. nov. (Cypriniformes: Cyprinidae) from southern Gabon.

J Fish Biol 2020 May 30;96(5):1218-1233. Epub 2019 May 30.

Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA.

We present and describe a new species of Enteromius, adding to the 16 species of Enteromius currently recorded from Gabon, West Africa. This new species is distinguished from all other Gabonese Enteromius by the presence of several distinct spots on the dorsal fin in combination with three or four round spots on the flanks. In Africa, it is superficially similar to Enteromius walkeri and with which it shares an unusual allometry in that the proportional length of the barbels decreases as the fish grows. Nevertheless, one can distinguish these species by vertebral number, maximum standard length, the length of the anterior barbels, the length of the caudal peduncle and in most specimens, the number of lateral-line and circumpeduncular scales. These two species also inhabit widely separated drainages, with E. walkeri occurring in coastal drainages of Ghana including the Pra and Ankobra Rivers and the new species occurring in tributaries of the Louetsi and Bibaka Rivers of Gabon, which are part of the Ogowe and Nyanga drainages, respectively. Despite extensive collections in those drainages the new species is known from only two localities, suggesting the importance of conservation of its known habitat.
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http://dx.doi.org/10.1111/jfb.13995DOI Listing
May 2020

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

Am J Transplant 2019 04 8;19(4):1024-1036. Epub 2018 Oct 8.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.

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.
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http://dx.doi.org/10.1111/ajt.15123DOI Listing
April 2019

Quantitative in vivo whole genome motility screen reveals novel therapeutic targets to block cancer metastasis.

Nat Commun 2018 06 14;9(1):2343. Epub 2018 Jun 14.

Department of Oncology, University of Alberta, Edmonton, AB, T6G 2E1, Canada.

Metastasis is the most lethal aspect of cancer, yet current therapeutic strategies do not target its key rate-limiting steps. We have previously shown that the entry of cancer cells into the blood stream, or intravasation, is highly dependent upon in vivo cancer cell motility, making it an attractive therapeutic target. To systemically identify genes required for tumor cell motility in an in vivo tumor microenvironment, we established a novel quantitative in vivo screening platform based on intravital imaging of human cancer metastasis in ex ovo avian embryos. Utilizing this platform to screen a genome-wide shRNA library, we identified a panel of novel genes whose function is required for productive cancer cell motility in vivo, and whose expression is closely associated with metastatic risk in human cancers. The RNAi-mediated inhibition of these gene targets resulted in a nearly total (>99.5%) block of spontaneous cancer metastasis in vivo.
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http://dx.doi.org/10.1038/s41467-018-04743-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6002534PMC
June 2018

Polyomavirus BK Nephropathy-Associated Transcriptomic Signatures: A Critical Reevaluation.

Transplant Direct 2018 Feb 2;4(2):e339. Epub 2018 Feb 2.

Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA.

Background: Recent work using DNA microarrays has suggested that genes related to DNA replication, RNA polymerase assembly, and pathogen recognition receptors can serve as surrogate tissue biomarkers for polyomavirus BK nephropathy (BKPyVN).

Methods: We have examined this premise by looking for differential regulation of these genes using a different technology platform (RNA-seq) and an independent set 25 biopsies covering a wide spectrum of diagnoses.

Results: RNA-seq could discriminate T cell-mediated rejection from other common lesions seen in formalin fixed biopsy material. However, overlapping RNA-seq signatures were found among all disease processes investigated. Specifically, genes previously reported as being specific for the diagnosis of BKPyVN were found to be significantly upregulated in T cell-mediated rejection, inflamed areas of fibrosis/tubular atrophy, as well as acute tubular injury.

Conclusions: In conclusion, the search for virus specific molecular signatures is confounded by substantial overlap in pathogenetic mechanisms between BKPyVN and nonviral forms of allograft injury. Clinical heterogeneity, overlapping exposures, and different morphologic patterns and stage of disease are a source of substantial variability in "Omics" experiments. These variables should be better controlled in future biomarker studies on BKPyVN, T cell-mediated rejection, and other forms of allograft injury, before widespread implementation of these tests in the transplant clinic.
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http://dx.doi.org/10.1097/TXD.0000000000000752DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5811268PMC
February 2018

The chloride intracellular channel 5A stimulates podocyte Rac1, protecting against hypertension-induced glomerular injury.

Kidney Int 2016 Apr 24;89(4):833-47. Epub 2016 Feb 24.

Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. Electronic address:

Glomerular capillary hypertension elicits podocyte remodeling and is a risk factor for the progression of glomerular disease. Ezrin, which links podocalyxin to actin in podocytes, is activated through the chloride intracellular channel 5A (CLIC5A)-dependent phosphatidylinositol 4,5 bisphosphate (PI[4,5]P2) accumulation. Because Rac1 is involved in podocyte actin remodeling and can promote PI[4,5]P2 production we determined whether CLIC5A-dependent PI[4,5]P2 generation and ezrin activation are mediated by Rac1. In COS7 cells, CLIC5A expression stimulated Rac1 but not Cdc42 or Rho activity. CLIC5A also stimulated phosphorylation of the Rac1 effector Pak1 in COS7 cells and in cultured mouse podocytes. CLIC5A-induced PI[4,5]P2 accumulation and Pak1 and ezrin phosphorylation were all Rac1 dependent. In DOCA/Salt hypertension, phosphorylated Pak increased in podocytes of wild-type, but not CLIC5-deficient mice. In DOCA/salt hypertensive mice lacking CLIC5, glomerular capillary microaneurysms were more frequent and albuminuria was greater than in wild-type mice. Thus, augmented hypertension-induced glomerular capillary injury in mice lacking CLIC5 results from abrogation of Rac1-dependent Pak and ezrin activation, perhaps reducing the tensile strength of the podocyte actin cytoskeleton.
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http://dx.doi.org/10.1016/j.kint.2016.01.001DOI Listing
April 2016

Multiplexed color-coded probe-based gene expression assessment for clinical molecular diagnostics in formalin-fixed paraffin-embedded human renal allograft tissue.

Clin Transplant 2016 Mar 3;30(3):295-305. Epub 2016 Feb 3.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.

Histopathologic diagnoses in transplantation can be improved with molecular testing. Preferably, molecular diagnostics should fit into standard-of-care workflows for transplant biopsies, that is, formalin-fixed paraffin-embedded (FFPE) processing. The NanoString(®) gene expression platform has recently been shown to work with FFPE samples. We aimed to evaluate its methodological robustness and feasibility for gene expression studies in human FFPE renal allograft samples. A literature-derived antibody-mediated rejection (ABMR) 34-gene set, comprised of endothelial, NK cell, and inflammation transcripts, was analyzed in different retrospective biopsy cohorts and showed potential to molecularly discriminate ABMR cases, including FFPE samples. NanoString(®) results were reproducible across a range of RNA input quantities (r = 0.998), with different operators (r = 0.998), and between different reagent lots (r = 0.983). There was moderate correlation between NanoString(®) with FFPE tissue and quantitative reverse transcription polymerase chain reaction (qRT-PCR) with corresponding dedicated fresh-stabilized tissue (r = 0.487). Better overall correlation with histology was observed with NanoString(®) (r = 0.354) than with qRT-PCR (r = 0.146). Our results demonstrate the feasibility of multiplexed gene expression quantification from FFPE renal allograft tissue. This represents a method for prospective and retrospective validation of molecular diagnostics and its adoption in clinical transplantation pathology.
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http://dx.doi.org/10.1111/ctr.12689DOI Listing
March 2016

Transplant biopsy beyond light microscopy.

BMC Nephrol 2015 Aug 7;16:132. Epub 2015 Aug 7.

Department of Laboratory Medicine and Pathology, University of Alberta, T6G 2S2, Edmonton, Canada.

Despite its long-standing status as the diagnostic "gold standard", the renal transplant biopsy is limited by a fundamental dependence on descriptive, empirically-derived consensus classification. The recent shift towards personalized medicine has resulted in an increased demand for precise, mechanism-based diagnoses, which is not fully met by the contemporary transplantation pathology standard of care. The expectation is that molecular techniques will provide novel pathogenetic insights that will allow for the identification of more accurate diagnostic, prognostic, and therapeutic targets. Here we review the current state of molecular renal transplantation pathology. Despite significant research activity and progress within the field, routine adoption of clinical molecular testing has not yet been achieved. The recent development of novel molecular platforms suitable for use with formalin-fixed paraffin-embedded tissue will offer potential solution for the major barriers to implementation. The recent incorporation of molecular diagnostic criteria into the 2013 Banff classification is a reflection of progress made and future directions in the area of molecular transplantation pathology. Transcripts related to endothelial injury and NK cell activation have consistently been shown to be associated with antibody-mediated rejection. Prospective multicenter validation and implementation of molecular diagnostics for major entities remains an unmet clinical need in transplantation. It is expected that an integrated system of transplantation pathology diagnosis comprising molecular, morphological, serological, and clinical variables will ultimately provide the greatest diagnostic precision.
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http://dx.doi.org/10.1186/s12882-015-0136-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528359PMC
August 2015

Immune Cell Infiltrates in Pituitary Adenomas: More Macrophages in Larger Adenomas and More T Cells in Growth Hormone Adenomas.

Endocr Pathol 2015 Sep;26(3):263-72

Department of Laboratory Medicine and Pathology, University of Alberta, 8440-112 Street, T6G 2B7, Edmonton, Alberta, Canada,

Tumor immune microenvironment has been gradually recognized as a key contributor to tumor development, progression, and control. Immune cell infiltrates in brain tumors have been increasingly studied, but few have published on immune cell infiltrates in pituitary adenomas. We quantitatively assessed the infiltration of macrophages and lymphocytes in 35 pituitary adenomas, including 9 densely granulated growth hormone (DG-GH), 9 sparsely granulated growth hormone (SG-GH), 9 null cell (NC), and 8 adrenocorticotropic hormone (ACTH) adenomas. All the adenomas showed varying degrees of CD68+ macrophage infiltration. While SG-GH adenomas were significantly larger in size than DG-GH and ACTH adenomas, the infiltration of CD68+ macrophages was significantly greater in SG-GH than in DG-GH and ACTH adenomas. Similarly, NC adenomas that were significantly larger than DG-GH and ACTH adenomas had significantly greater infiltration of CD68+ macrophages than DG-GH and ACTH adenomas. The numbers of CD68+ macrophages were positively correlated with the tumor sizes and Knosp classification grades for tumor invasiveness. The infiltration of CD4+ and CD8+ T cells was relatively scant in these adenomas, but GH adenomas exhibited significantly more CD4+ and CD8+ T cells than non-GH adenomas. Both DG-GH and SG-GH adenomas had significantly more CD4+ cells than ACTH adenomas and significantly more CD8+ cells than NC adenomas. These results suggest an association of CD68+ macrophage infiltration with an increase in the pituitary adenoma size and invasiveness. Our observation contributes to understanding the growth environment of pituitary adenomas, for which adjuvant immunotherapy may help to constrain the tumor enlargement and invasiveness.
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http://dx.doi.org/10.1007/s12022-015-9383-6DOI Listing
September 2015

Molecular nephropathology: ready for prime time?

Am J Physiol Renal Physiol 2015 Aug 27;309(3):F185-8. Epub 2015 May 27.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada

In the current era of precision medicine, the existing nephropathology paradigm of light microscopy, immunofluorescence, and electron microscopy will become increasingly insufficient. There will be an expectation to supplement these traditional diagnostic tools with patient-specific information related to a growing understanding of molecular pathophysiology. Next generation sequencing technologies are expected to play a key role in the future of nephropathology, but transcriptomics is poised to represent the first major foray into routine molecular testing. The introduction of molecular techniques into clinical nephropathology has been hindered in part by the reliance of existing platforms on fresh tissue samples. The NanoString gene expression system works with formalin-fixed paraffin-embedded tissue and thus represents a promising solution to this technical barrier that may finally allow for the translation of recent transcriptomics discoveries into the enhancement of patient care. Widespread adoption of this new diagnostic dimension will require ongoing multidisciplinary cooperation between pathologists and clinicians, including molecular testing consensus generation and rigorous multicenter validation.
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http://dx.doi.org/10.1152/ajprenal.00153.2015DOI Listing
August 2015

A practical and novel method to extract genomic DNA from blood collection kits for plasma protein preservation.

J Vis Exp 2013 May 18(75):e4241. Epub 2013 May 18.

Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Emory University School of Medicine and Children's Health Care of Atlanta, USA.

Laboratory tests can be done on the cellular or fluid portions of the blood. The use of different blood collection tubes determines the portion of the blood that can be analyzed (whole blood, plasma or serum). Laboratories involved in studying the genetic basis of human disorders rely on anticoagulated whole blood collected in EDTA-containing vacutainer as the source of DNA for genetic / genomic analysis. Because most clinical laboratories perform biochemical, serologic and viral testing as a first step in phenotypic outcome investigation, anticoagulated blood is also collected in heparin-containing tube (plasma tube). Therefore when DNA and plasma are needed for simultaneous and parallel analyses of both genomic and proteomic data, it is customary to collect blood in both EDTA and heparin tubes. If blood could be collected in a single tube and serve as a source for both plasma and DNA, that method would be considered an advancement to existing methods. The use of the compacted blood after plasma extraction represents an alternative source for genomic DNA, thus minimizing the amount of blood samples processed and reducing the number of samples required from each patient. This would ultimately save time and resources. The BD P100 blood collection system for plasma protein preservation were created as an improved method over previous plasma or serum collection tubes(1), to stabilize the protein content of blood, enabling better protein biomarker discovery and proteomics experimentation from human blood. The BD P100 tubes contain 15.8 ml of spray-dried K2EDTA and a lyophilized proprietary broad spectrum cocktail of protease inhibitors to prevent coagulation and stabilize the plasma proteins. They also include a mechanical separator, which provides a physical barrier between plasma and cell pellets after centrifugation. Few methods have been devised to extract DNA from clotted blood samples collected in old plasma tubes(2-4). Challenges from these methods were mainly associated with the type of separator inside the tubes (gel separator) and included difficulty in recovering the clotted blood, the inconvenience of fragmenting or dispersing the clot, and obstruction of the clot extraction by the separation gel. We present the first method that extracts and purifies genomic DNA from blood drawn in the new BD P100 tubes. We compare the quality of the DNA sample from P100 tubes to that from EDTA tubes. Our approach is simple and efficient. It involves four major steps as follows: 1) the use of a plasma BD P100 (BD Diagnostics, Sparks, MD, USA) tube with mechanical separator for blood collection, 2) the removal of the mechanical separator using a combination of sucrose and a sterile paperclip metallic hook, 3) the separation of the buffy coat layer containing the white cells and 4) the isolation of the genomic DNA from the buffy coat using a regular commercial DNA extraction kit or a similar standard protocol.
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http://dx.doi.org/10.3791/4241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3698940PMC
May 2013

Fusion tyrosine kinase NPM-ALK Deregulates MSH2 and suppresses DNA mismatch repair function novel insights into a potent oncoprotein.

Am J Pathol 2011 Jul 24;179(1):411-21. Epub 2011 May 24.

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.

The fusion tyrosine kinase NPM-ALK is central to the pathogenesis of ALK-positive anaplastic large cell lymphoma (ALK(+)ALCL). We recently identified that MSH2, a key DNA mismatch repair (MMR) protein integral to the suppression of tumorigenesis, is an NPM-ALK-interacting protein. In this study, we found in vitro evidence that enforced expression of NPM-ALK in HEK293 cells suppressed MMR function. Correlating with these findings, six of nine ALK(+)ALCL tumors displayed evidence of microsatellite instability, as opposed to none of the eight normal DNA control samples (P = 0.007, Student's t-test). Using co-immunoprecipitation, we found that increasing levels of NPM-ALK expression in HEK293 cells resulted in decreased levels of MSH6 bound to MSH2, whereas MSH2·NPM-ALK binding was increased. The NPM-ALK·MSH2 interaction was dependent on the activation/autophosphorylation of NPM-ALK, and the Y191 residue of NPM-ALK was a crucial site for this interaction and NPM-ALK-mediated MMR suppression. MSH2 was found to be tyrosine phosphorylated in the presence of NPM-ALK. Finally, NPM-ALK impeded the expected DNA damage-induced translocation of MSH2 out of the cytoplasm. To conclude, our data support a model in which the suppression of MMR by NPM-ALK is attributed to its ability to interfere with normal MSH2 biochemistry and function.
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http://dx.doi.org/10.1016/j.ajpath.2011.03.045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3123797PMC
July 2011