Automated Urinary Chemokine Assays for Noninvasive Detection of Kidney Transplant Rejection: A Prospective Cohort Study

RATIONALE & OBJECTIVE

Prior studies have demonstrated the diagnostic potential of urinary chemokines C-X-C motif ligand 9 (CXCL9) and CXCL10 for kidney transplant rejection. However, their benefit in addition to clinical information has not been demonstrated. We evaluated the diagnostic performance for detecting acute rejection of urinary CXCL9 and CXCL10 when integrated with clinical information.

STUDY DESIGN

Single-center prospective cohort study.

SETTING & PARTICIPANTS

We analyzed 1,559 biopsy-paired urinary samples from 622 kidney transplants performed between April 2013 and July 2019 at a single transplant center in Belgium. External validation was performed in 986 biopsy-paired urinary samples.

TESTS COMPARED

We quantified urinary CXCL9 (uCXCL9) and CXCL10 (uCXCL10) using an automated immunoassay platform and normalized the values to urinary creatinine. Urinary chemokines were incorporated into a multivariable model with routine clinical markers (estimated glomerular filtration rate, donor-specific antibodies, and polyoma viremia) (integrated model). This model was then compared with the tissue diagnosis according to the Banff classification for acute rejection.

OUTCOME

Acute rejection detected on kidney biopsy using the Banff classification.

RESULTS

Chemokines integrated with routine clinical markers had high diagnostic value for detection of acute rejection (n=150) (receiver operating characteristic area under the curve 81.3% [95% CI, 77.6-85.0]). The integrated model would help avoid 59 protocol biopsies per 100 patients when the risk for rejection is predicted to be below 10%. The performance of the integrated model was similar in the external validation cohort.

LIMITATIONS

The cross-sectional nature obviates investigating the evolution over time and prediction of future rejection.

CONCLUSIONS

The use of an integrated model of urinary chemokines and clinical markers for noninvasive monitoring of rejection could enable a reduction in the number of biopsies. Urinary chemokines may be useful noninvasive biomarkers whose use should be further studied in prospective randomized trials to clarify their role in guiding clinical care and the use of biopsies to detect rejection after kidney transplantation.

PLAIN-LANGUAGE SUMMARY

Urinary chemokines CXCL9 and CXCL10 have been suggested to be good noninvasive biomarkers of kidney transplant rejection. However, defining a context of use and integration with clinical information is necessary before clinical implementation can begin. In this study, we demonstrated that urinary chemokines CXCL9 and CXCL10, together with clinical information, have substantial diagnostic accuracy for the detection of acute kidney transplant rejection. Application of urinary chemokines together with clinical information may guide biopsy practices following kidney transplantation and potentially reduce the need for kidney transplant biopsies.

Needs, barriers and facilitators for a healthier lifestyle in haemodialysis patients: The GoodRENal project

BACKGROUND

Malnutrition, sedentary lifestyle, cognitive dysfunction and poor psychological well-being are often reported in patients on haemodialysis (HD).

AIMS

We aimed to explore needs, barriers and facilitators-as perceived by patients, their carers, and healthcare professionals (HCPs) for increasing the adherence to the diet, to physical activity and cognition and psychological well-being.

METHODS

This is an observational cross-sectional study following the STROBE statement. This study is part of an ERASMUS+ project, GoodRENal-aiming to develop digital tools as an educational approach to patients on HD. For that, the GoodRENal comprises HD centers located in four Belgium, Greece, Spain and Sweden. Exploratory questionnaires were developed regarding the perceived needs, barriers and facilitators regarding the diet, physical activity, cognition and psychological well-being from the perspective of patients, their carers and HCPs.

RESULTS

In total, 38 patients, 34 carers and 38 HCPs were included. Nutrition: For patients and carers, the main needs to adhere to the diet included learning more about nutrients and minerals. For patients, the main barrier was not being able to eat what they like. Physical activity: As needs it was reported information about type of appropriate physical activity, while fatigue was listed as the main barrier. For Cognitive and emotional state, it was perceived as positive for patients and carers perception but not for HCPs. The HCPs identified as needs working as a team, having access to specialised HCP and being able to talk to patients in private.

CONCLUSIONS

Patients and their carers listed as needs guidance regarding nutrition and physical activity but were positive with their cognitive and emotional state. The HCPs corroborated these needs and emphasised the importance of teamwork and expert support.

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.

Focal segmental glomerulosclerosis associated with the use of the IL-23 inhibitor guselkumab

We report a case of a 38-year-old man who developed a nephrotic syndrome shortly after the start of guselkumab for the treatment of plaque psoriasis. Renal biopsy showed focal segmental glomerulosclerosis (FSGS). The clinical course of our case is highly suspect for drug-induced FSGS since the nephrotic syndrome resolved after cessation of the drug without relapse (2 years of follow-up). To the best of our knowledge, this is the first case describing FSGS lesions associated with the use of an interleukin-23 inhibitor.

Association of Predicted HLA T-Cell Epitope Targets and T-Cell-Mediated Rejection After Kidney Transplantation

RATIONALE & OBJECTIVE

The relationship between human leukocyte antigen (HLA) molecular mismatches and T-cell-mediated rejection (TCMR) is unknown. We investigated the associations between the different donor HLA-derived T-cell targets and the occurrence of TCMR and borderline histologic changes suggestive of TCMR after kidney transplantation.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

All kidney transplant recipients at a single center between 2004 and 2013 with available biopsy data and a DNA sample for high-resolution HLA donor/recipient typing (N = 893).

EXPOSURE

Scores calculated by the HLA matching algorithm PIRCHE-II and HLA eplet mismatches.

OUTCOME

TCMR, borderline changes suggestive of TCMR, and allograft failure.

ANALYTICAL APPROACH

Multivariable cause-specific hazards models were fit to characterize the association between HLA epitopes targets and study outcomes.

RESULTS

We found 277 patients developed TCMR, and 134 developed only borderline changes suggestive of TCMR on at least 1 biopsy. In multivariable analyses, only the PIRCHE-II scores for HLA-DRB1 and HLA-DQB1 were independently associated with the occurrence of TCMR and with allograft failure; this was not the case for HLA class I molecules. If restricted to rejection episodes within the first 3 months after transplantation, only the T-cell epitope targets originating from the donor's HLA-DRB1 and HLA-DQB1, but not class I molecules, were associated with the early acute TCMR. Also, the median PIRCHE-II score for HLA class II was statistically different between the patients with TCMR compared to the patients without TCMR (129 [IQR, 60-240] vs 201 [IQR, 96-298], respectively; P < 0.0001). These differences were not observed for class I PIRCHE-II scores.

LIMITATIONS

Observational clinical data and residual confounding.

CONCLUSIONS

In the absence of HLA-DSA, HLA class II but not class I mismatches are associated with early episodes of acute TCMR and allograft failure. This suggests that current immunosuppressive therapies are largely able to abort the most deleterious HLA class I-directed alloimmune processes; however, alloresponses against HLA-DRB1 and HLA-DQB1 molecular mismatches remain insufficiently suppressed.

PLAIN-LANGUAGE SUMMARY

Genetic differences in the human leukocyte antigen (HLA) complex between kidney transplant donors and recipients play a central role in T-cell-mediated rejection (TCMR), which can lead to failure of the transplanted kidney. Evaluating this genetic disparity (mismatch) in the HLA complex at the molecular (epitope) level could contribute to better prediction of the immune response to the donor organ posttransplantation. We investigated the associations of the different donor HLA-derived T-cell epitope targets and scores obtained from virtual crossmatch algorithms with the occurrence of TCMR, borderline TCMR, and graft failure after kidney transplantation after taking into account the influence of donor-specific anti-HLA antibodies. This study illustrates the greater importance of the molecular mismatches in class II molecules compared to class I HLA molecules.

MicroRNAs: emerging biomarkers and therapeutic targets of bone fragility in chronic kidney disease

Bone fragility is highly prevalent, yet underdiagnosed in patients with chronic kidney disease. Incomplete understanding of the pathophysiology and limitations of current diagnostics contribute to therapeutic hesitation, if not nihilism. This narrative review addresses the question of whether microRNAs (miRNAs) may improve therapeutic decision making in osteoporosis and renal osteodystrophy. miRNAs are key epigenetic regulators of bone homeostasis and show promise as both therapeutic targets and as biomarkers, primarily of bone turnover. Experimental studies show that miRNAs are involved in several osteogenic pathways. Clinical studies exploring the usefulness of circulating miRNAs for fracture risk stratification and for guiding and monitoring therapy are few and, so far, provide inconclusive results. Likely, (pre)analytical heterogeneity contributes to these equivocal results. In conclusion, miRNAs are promising in metabolic bone disease, both as a diagnostic tool and as therapeutic targets, but not yet ready for clinical prime time.

Clinicopathological characteristics and disease chronicity in native kidney biopsies in Flanders

Background

The Flemish Collaborative Glomerulonephritis Group (FCGG) registry provides complete population data on kidney disease epidemiology in the region of Flanders (Belgium), as it captures all native kidney biopsies performed in its population of 6.5 million inhabitants.

Methods

From 2017 until 2019, 2054 adult kidney biopsies were included from 26 nephrology centers (one biopsy per patient). Data on nephrotic and nephritic syndrome were available in 1992 and 2026 biopsies, respectively. In a subgroup of 898 biopsies containing ≥10 glomeruli from 2018 to 2019, disease chronicity was graded using the Mayo Clinic Chronicity Score (MCCS). The association between clinical variables and MCCS was determined using simple and multiple linear regression models.

Results

Nephrotic syndrome (present in 378 patients, 19.0%) was most frequently caused by minimal change disease in younger patients (18-44 years), membranous nephropathy in older patients (45-74 years) and amyloidosis in the elderly (>75 years). Nephritic syndrome (present in 421 patients, 20.8%) was most frequently caused by immunoglobulin A nephropathy (IgAN) in younger patients (18-64 years) and ANCA-associated vasculitis (AAV) in older patients (>64 years). AAV and IgAN were the most frequent underlying diagnoses in biopsies in which crescents were identified. In multivariable analysis, acute and chronic kidney disease and diagnoses of diabetic kidney disease, nephrosclerosis and hyperoxaluria/hypercalcemic nephropathy were associated with the highest MCCS increases.

Conclusions

The FCGG registry validates data from previous Western European registries and provides a snapshot of disease chronicity in the whole biopsied Flemish population.

Global Policy Barriers and Enablers to Exercise and Physical Activity in Kidney Care

OBJECTIVE

Impairment in physical function and physical performance leads to decreased independence and health-related quality of life in people living with chronic kidney disease and end-stage kidney disease. Physical activity and exercise in kidney care are not priorities in policy development. We aimed to identify global policy-related enablers, barriers, and strategies to increase exercise participation and physical activity behavior for people living with kidney disease.

DESIGN AND METHODS

Guided by the Behavior Change Wheel theoretical framework, 50 global renal exercise experts developed policy barriers and enablers to exercise program implementation and physical activity promotion in kidney care. The consensus process consisted of developing themes from renal experts from North America, South America, Continental Europe, United Kingdom, Asia, and Oceania. Strategies to address enablers and barriers were identified by the group, and consensus was achieved.

RESULTS

We found that policies addressing funding, service provision, legislation, regulations, guidelines, the environment, communication, and marketing are required to support people with kidney disease to be physically active, participate in exercise, and improve health-related quality of life. We provide a global perspective and highlight Japanese, Canadian, and other regional examples where policies have been developed to increase renal physical activity and rehabilitation. We present recommendations targeting multiple stakeholders including nephrologists, nurses, allied health clinicians, organizations providing renal care and education, and renal program funders.

CONCLUSIONS

We strongly recommend the nephrology community and people living with kidney disease take action to change policy now, rather than idly waiting for indisputable clinical trial evidence that increasing physical activity, strength, fitness, and function improves the lives of people living with kidney disease.

The importance of physical performance in the assessment of patients on haemodialysis: A survival analysis

Background

Physical performance is an important determinant of quality of life in patients on haemodialysis. An association between physical performance and survival could further enhance the importance of physical performance. We aimed to assess the association between different measures of physical performance and survival in dialysis patients.

Methods

117 patients on haemodialysis were included from December 2016 and followed up to September 2020. Muscle strength (quadriceps, handgrip strength, and sit-to-stand), exercise capacity (six-minute walking test, 6MWT) and the risk of falls (Dialysis Fall Index, Tinetti, and Frailty and Injuries: Cooperative Studies of Intervention Techniques) were measured at the time of inclusion. Hospitalisation, morbidity (Davies Stoke index) and death were recorded. Data were analysed by least squares linear regression models and competing risks survival hazard models.

Results

During the observation period (median 33, min 30 max 45 months), 45 patients died (= 38.5%), resulting in a mortality rate of 15% per year. Cardiovascular disease (42.9%) was the most common cause of death. All domains of physical performance were associated with mortality, with the highest hazards for an increased risk of falls (Hazard Ratio (HR) = 20.4, p = 0.003) and poor exercise capacity (HR = 7.4, p<0.001). A score lower than 298 meters (specificity = 0.583; sensitivity = 0.889) on the 6MWT was established as a haemodialysis-specific cut-off point for mortality risk. Each increase in 6MWT (m) corresponded with a 0.4% decrease in mortality risk (HR = 0.996, 95%CI [0.994; 0.998]). The 6MWT as also associated with comorbidity (F-value = 6.1, p = 0.015). Physical performance was not associated with hospitalisation.

Conclusions

The 6MWT is associated with mortality in patients on haemodialysis and can be considered as a valid assessment tool to identify high-risk patients.

Circulating Donor-Specific Anti-HLA Antibodies Associate With Immune Activation Independent of Kidney Transplant Histopathological Findings

Despite the critical role of cytokines in allograft rejection, the relation of peripheral blood cytokine profiles to clinical kidney transplant rejection has not been fully elucidated. We assessed 28 cytokines through multiplex assay in 293 blood samples from kidney transplant recipients at time of graft dysfunction. Unsupervised hierarchical clustering identified a subset of patients with increased pro-inflammatory cytokine levels. This patient subset was hallmarked by a high prevalence (75%) of donor-specific anti-human leukocyte antigen antibodies (HLA-DSA) and histological rejection (70%) and had worse graft survival compared to the group with low cytokine levels (HLA-DSA in 1.7% and rejection in 33.7%). Thirty percent of patients with high pro-inflammatory cytokine levels and HLA-DSA did not have histological rejection. Exploring the cellular origin of these cytokines, we found a corresponding expression in endothelial cells, monocytes, and natural killer cells in single-cell RNASeq data from kidney transplant biopsies. Finally, we confirmed secretion of these cytokines in HLA-DSA-mediated cross talk between endothelial cells, NK cells, and monocytes. In conclusion, blood pro-inflammatory cytokines are increased in kidney transplant patients with HLA-DSA, even in the absence of histology of rejection. These observations challenge the concept that histology is the gold standard for identification of ongoing allo-immune activation after transplantation.

Prevalence, progression and implications of breast artery calcification in patients with chronic kidney disease

Breast arterial calcification (BAC) is increasingly recognized as a specific marker of medial calcification. The present retrospective observational cohort study aimed to define the prevalence, progression rate, risk factors and clinical implications of BAC in chronic kidney disease (CKD) patients across stages of disease. The presence and extent of BAC were determined on mammograms in 310 females (58.7 ± 10.8 years, Caucasian) with CKD across various stages of disease [CKD G2-5D n = 132; transplant (Tx) recipients n = 178]. In a subset of 88 patients, repeat mammography was performed, allowing us to calculate the annualized BAC rate. Overall, BAC was observed in 34.7% of the patients. BAC prevalence (P = 0.02) and BAC score (P = 0.05) increased along the progression of CKD. In the overall cohort, patients with BAC were characterized by older age, more cardiovascular disease, more inflammation, higher pulse pressure and borderline higher prevalence of diabetes and were more often treated with a vitamin K antagonist (VKA). The BAC progression rate was significantly lower in Tx patients as compared with CKD G5D. Progressors were characterized by more inflammation, worse kidney function, higher BAC score and higher serum phosphate level (Tx only) at baseline and were more often treated with a VKA. Major adverse cardiovascular event-free survival was significantly worse in Tx patients with BAC. In conclusion, BAC is common among CKD patients, progresses at a slower pace in Tx patients as compared with CKD 5D and associates with dismal cardiovascular outcomes. BAC score, kidney function, serum phosphate at baseline and VKA usage seem to be important determinants of progression.

Renal Infarction Imaged With [18F]Prostate-Specific Membrane Antigen-1007 PET/CT

ABSTRACT

A 61-year-old post-renal transplant man developed pain in the region of the allograft 4 days after transplantation. Contrast-enhanced CT scan revealed multiple small perfusion defects in the renal graft cortex. Multifocal renal cortical infarction was suspected. A [99mTc]Tc-DMSA SPECT/CT showed several small regions with decreased uptake. In addition, an [18F]PSMA-1007 PET/CT confirmed these uptake defects and revealed additional defects. The renal cortical infarctions presumably originated from intraoperative emboli emerging from the arterial anastomosis. Treatment with acetylsalicylic acid 100 mg led to favorable evolution of the renal function biochemically. Follow-up DMSA scintigraphy 3 months later showed resolution of the renal cortical defects.

Epidemiology of native kidney disease in Flanders: results from the FCGG kidney biopsy registry

Background

The Flemish Collaborative Glomerulonephritis Group (FCGG) registry is the first population-based native kidney biopsy registry in Flanders, Belgium. In this first analysis, we report on patient demographics, frequency distribution and incidence rate of biopsied kidney disease in adults in Flanders.

Methods

From January 2017 to December 2019, a total of 2054 adult first native kidney biopsies were included. A ‘double diagnostic coding’ strategy was used, in which every biopsy sample received a histopathological and final clinical diagnosis. Frequency distribution and incidence rate of both diagnoses were reported and compared with other European registries.

Results

The median age at biopsy was 61.1 years (interquartile range, 46.1–71.7); male patients were more prevalent (62.1%) and biopsy incidence rate was 129.3 per million persons per year. Immunoglobulin A nephropathy was the most frequently diagnosed kidney disease (355 biopsies, 17.3% of total) with a similar frequency as in previously published European registries. The frequency of tubulointerstitial nephritis (220 biopsies, 10.7%) and diabetic kidney disease (154 biopsies, 7.5%) was remarkably higher, which may be attributed to changes in disease incidence as well as biopsy practices. Discordances between histopathological and final clinical diagnoses were noted and indicate areas for improvement in diagnostic coding systems.

Conclusions

The FCGG registry, with its ‘double diagnostic coding’ strategy, provides useful population-based epidemiological data on a large Western European population and allows subgroup selection for future research.

Forecasting of Patient-Specific Kidney Transplant Function With a Sequence-to-Sequence Deep Learning Model

IMPORTANCE

Like other clinical biomarkers, trajectories of estimated glomerular filtration rate (eGFR) after kidney transplant are characterized by intra-individual variability. These fluctuations hamper the distinction between alarming graft functional deterioration or harmless fluctuation within the patient-specific expected reference range of eGFR.

OBJECTIVE

To determine whether a deep learning model could accurately predict the patient-specific expected reference range of eGFR after kidney transplant.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter diagnostic study consisted of a derivation cohort of 933 patients who received a kidney transplant between 2004 and 2013 with 100 867 eGFR measurements from University Hospitals Leuven, Belgium, and 2 independent test cohorts: with 39 999 eGFR measurements from 1 170 patients, 1 from University Hospitals Leuven, Belgium, receiving transplants between 2013 and 2018 and 1 from Hannover Medical School, Germany, receiving transplants between 2003 and 2007. Patients receiving a single kidney transplant, with consecutive eGFR measurements were included. Data were analyzed from February 2019 to April 2021.

EXPOSURES

In the derivation cohort 100 867 eGFR measurements were available for analysis and 39 999 eGFR measurements from the independent test cohorts.

MAIN OUTCOMES AND MEASURES

A sequence-to-sequence model was developed for prediction of a patient-specific expected range of eGFR, based on previous eGFR values. The primary outcome was the performance of the deep learning sequence-to-sequence model in the 2 independent cohorts.

RESULTS

In this diagnostic study, a total of 933 patients in the training sets (mean [SD] age, 53.5 [13.3] years; 570 male [61.1%]) and 1170 patients in the independent test sets (cohort 1 [n = 621]: mean [SD] age, 58.5 [12.1] years; 400 male [64.4%]; cohort 2 [n = 549]: mean [SD] age, 50.1 [13.0] years; 316 male [57.6%]) who received a single kidney transplant most frequently from deceased donors, the sequence-to-sequence models accurately predicted future patient-specific eGFR trajectories within the first 3 months after transplant, based on the previous graft eGFR values (root mean square error, 6.4-8.9 mL/min/1.73 m2). The sequence-to-sequence model predictions outperformed the more conventional autoregressive integrated moving average prediction model, at all input/output number of eGFR values.

CONCLUSIONS AND RELEVANCE

In this diagnostic study, a sequence-to-sequence deep learning model was developed and validated for individual forecasting of kidney transplant function. The patient-specific sequence predictions could be used in clinical practice to guide physicians on deviations from the expected intra-individual variability, rather than relating the individual results to the reference range of the healthy population.

Plasma-Derived microRNAs Are Influenced by Acute and Chronic Exercise in Patients With Heart Failure With Reduced Ejection Fraction

Background: Exercise training improves VO₂peak in heart failure with reduced ejection fraction (HFrEF), but the effect is highly variable as it is dependent on peripheral adaptations. We evaluated changes in plasma-derived miRNAs by acute and chronic exercise to investigate whether these can mechanistically be involved in the variability of exercise-induced adaptations.

Methods: Twenty-five male HFrEF patients (left ventricular ejection fraction < 40%, New York Heart Association class ≥ II) participated in a 15-week combined strength and aerobic training program. The effect of training on plasma miRNA levels was compared to 21 male age-matched sedentary HFrEF controls. Additionally, the effect of a single acute exercise bout on plasma miRNA levels was assessed. Levels of 5 miRNAs involved in pathways relevant for exercise adaptation (miR-23a, miR-140, miR-146a, miR-191, and miR-210) were quantified using RT-qPCR and correlated with cardiopulmonary exercise test (CPET), echocardiographic, vascular function, and muscle strength variables.

Results: Expression levels of miR-146a decreased with training compared to controls. Acute exercise resulted in a decrease in miR-191 before, but not after training. Baseline miR-23a predicted change in VO₂peak independent of age and left ventricular ejection fraction (LVEF). Baseline miR-140 was independently correlated with change in load at the respiratory compensation point and change in body mass index, and baseline miR-146a with change in left ventricular mass index.

Conclusion: Plasma-derived miRNAs may reflect the underlying mechanisms of exercise-induced adaptation. In HFrEF patients, baseline miR-23a predicted VO₂peak response to training. Several miRNAs were influenced by acute or repeated exercise. These findings warrant exploration in larger patient populations and further mechanistic in vitro studies on their molecular involvement.

miR-181c level predicts response to exercise training in patients with heart failure and preserved ejection fraction: an analysis of the OptimEx-Clin trial

AIMS

In patients with heart failure with preserved ejection fraction (HFpEF), exercise training improves the quality of life and aerobic capacity (peakV·O2). Up to 55% of HF patients, however, show no increase in peakV·O2 despite adequate training. We hypothesized that circulating microRNAs (miRNAs) can distinguish exercise low responders (LR) from exercise high responders (HR) among HFpEF patients.

METHODS AND RESULTS

We selected HFpEF patients from the Optimizing Exercise Training in Prevention and Treatment of Diastolic HF (OptimEx) study which attended ≥70% of training sessions during 3 months (n = 51). Patients were defined as HR with a change in peakV·O2 above median (6.4%), and LR as below median (n = 30 and n = 21, respectively). Clinical, ergospirometric, and echocardiographic characteristics were similar between LR and HR. We performed an miRNA array (n = 377 miRNAs) in 14 age- and sex-matched patients. A total of 10 miRNAs were upregulated in LR, of which 4 correlated with peakV·O2. Validation in the remaining 37 patients indicated that high miR-181c predicted reduced peakV·O2 response (multiple linear regression, β = -2.60, P = 0.011), and LR status (multiple logistic regression, odds ratio = 0.48, P = 0.010), independent of age, sex, body mass index, and resting heart rate. Furthermore, miR-181c decreased in LR after exercise training (P-group = 0.030, P-time = 0.048, P-interaction = 0.037). An in silico pathway analysis identified several downstream targets involved in exercise adaptation.

CONCLUSIONS

Circulating miR-181c is a marker of the response to exercise training in HFpEF patients. High miR-181c levels can aid in identifying LR prior to training, providing the possibility for individualized management.

Current Methodological Challenges of Single-Cell and Single-Nucleus RNA-Sequencing in Glomerular Diseases

Single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA-seq (snRNA-seq) allow transcriptomic profiling of thousands of cells from a renal biopsy specimen at a single-cell resolution. Both methods are promising tools to unravel the underlying pathophysiology of glomerular diseases. This review provides an overview of the technical challenges that should be addressed when designing single-cell transcriptomics experiments that focus on glomerulopathies. The isolation of glomerular cells from core needle biopsy specimens for single-cell transcriptomics remains difficult and depends upon five major factors. First, core needle biopsies generate little tissue material, and several samples are required to identify glomerular cells. Second, both fresh and frozen tissue samples may yield glomerular cells, although every experimental pipeline has different (dis)advantages. Third, enrichment for glomerular cells in human tissue before single-cell analysis is challenging because no effective standardized pipelines are available. Fourth, the current warm cell-dissociation protocols may damage glomerular cells and induce transcriptional artifacts, which can be minimized by using cold dissociation techniques at the cost of less efficient cell dissociation. Finally, snRNA-seq methods may be superior to scRNA-seq in isolating glomerular cells; however, the efficacy of snRNA-seq on core needle biopsy specimens remains to be proven. The field of single-cell omics is rapidly evolving, and the integration of these techniques in multiomics assays will undoubtedly create new insights in the complex pathophysiology of glomerular diseases.

Deconvolution of Focal Segmental Glomerulosclerosis Pathophysiology Using Transcriptomics Techniques

Background

Focal segmental glomerulosclerosis is a histopathological pattern of renal injury and comprises a heterogeneous group of clinical conditions with different pathophysiology, clinical course, prognosis, and treatment. Nevertheless, subtype differentiation in clinical practice often remains challenging, and we currently lack reliable diagnostic, prognostic, and therapeutic biomarkers. The advent of new transcriptomics techniques in kidney research poses great potential in the identification of gene expression biomarkers that can be applied in clinical practice.

Summary

Transcriptomics techniques have been completely revolutionized in the last 2 decades, with the evolution from low-throughput reverse-transcription polymerase chain reaction and in situ hybridization techniques to microarrays and next-generation sequencing techniques, including RNA-sequencing and single-cell transcriptomics. The integration of human gene expression profiles with functional in vitro and in vivo experiments provides a deeper mechanistic insight into the candidate genes, which enable the development of novel-targeted therapies. The correlation of gene expression profiles with clinical outcomes of large patient cohorts allows for the development of clinically applicable biomarkers that can aid in diagnosis and predict prognosis and therapy response. Finally, the integration of transcriptomics with other "omics" modalities creates a holistic view on disease pathophysiology.

Key Messages

New transcriptomics techniques allow high-throughput gene expression profiling of patients with focal segmental glomerulosclerosis (FSGS). The integration with clinical outcomes and fundamental mechanistic studies enables the discovery of new clinically useful biomarkers that will finally improve the clinical outcome of patients with FSGS.

Beta-Trace Protein as a Potential Marker of Acute Kidney Injury: A Pilot Study

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication among patients in the intensive care unit (ICU). The limitations of serum Cr (sCr) in timely detecting AKI are well known. Beta-trace protein (BTP) is emerging as a novel endogenous glomerular filtration rate marker. The aim of this study was to explore the role of BTP as a marker of AKI.

METHODS

Patients admitted to the ICU undergoing surgery were included. BTP, sCr, Cystatin C (CysC), and neutrophil gelatinase-associated lipocalin (NGAL) were measured preoperatively, postoperatively (post-op), and at the first (D1) and second (D2) post-op day. AKI was defined as an increase of sCr to ≥1.5-fold from baseline within 2 days after surgery.

RESULTS

Of the 52 patients studied, 10 patients (19%) developed AKI. Patients with AKI were older (69.6 ± 10.7 vs. 58.1 ± 16.7 years, p = 0.043) and had a longer length of ICU stay (13 [IQR 6-49] vs. 6 [IQR 5-8] days, p = 0.032). Between the 2 groups, the evolution of BTP, sCr, CysC, and NGAL over time differed significantly, with overall higher values in the AKI group. ROC analysis for the detection of AKI within 2 days after surgery showed a great accuracy for BTP. The area under the curve (AUC) for BTP post-op; D1; and D2 was, respectively, 0.869 ± 0.049; 0.938 ± 0.035; and 0.943 ± 0.032. The discriminative power of a BTP measurement on D1 was superior in detecting AKI compared to NGAL (adjusted p value = 0.027). We could not detect a significant difference between the AUCs of other biomarkers (NGAL, sCr, and CysC).

CONCLUSION

Serum BTP is a promising marker for diagnosing AKI in ICU patients undergoing surgery.

Circulating microRNA as predictors for exercise response in heart failure with reduced ejection fraction

AIMS

Exercise training is a powerful adjunctive therapy in patients with heart failure with reduced ejection fraction (HFrEF), but ca. 55% of patients fail to improve VO2peak. We hypothesize that circulating microRNAs (miRNAs), as epigenetic determinants of VO2peak, can distinguish exercise responders (ER) from exercise non-responders (ENR).

METHODS AND RESULTS

We analysed 377 miRNAs in 18 male HFrEF patients (9 ER and 9 ENR) prior to 15 weeks of exercise training using a miRNA array. ER and ENR were defined as change in VO2peak of >20% or <6%, respectively. First, unsupervised clustering analysis of the miRNA pattern was performed. Second, differential expression of miRNA in ER and ENR was analysed and related to percent change in VO2peak. Third, a gene set enrichment analysis was conducted to detect targeted genes and pathways. Baseline characteristics and training volume were similar between ER and ENR. Unsupervised clustering analysis of miRNAs distinguished ER from ENR with 83% accuracy. A total of 57 miRNAs were differentially expressed in ENR vs. ER. A panel of seven miRNAs up-regulated in ENR (Let-7b, miR-23a, miR-140, miR-146a, miR-191, miR-210, and miR-339-5p) correlated with %changeVO2peak (all P < 0.05) and predicted ENR with area under the receiver operating characteristic curves ≥0.77. Multiple pathways involved in exercise adaptation processes were identified.

CONCLUSION

A fingerprint of seven miRNAs involved in exercise adaptation processes is highly correlated with VO2peak trainability in HFrEF, which holds promise for the prediction of training response and patient-targeted exercise prescription.

Exercise training in patients after kidney transplantation

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. Next to the risk of allograft failure, major obstacles for disease-free survival after kidney transplantation include a higher incidence of cancer, infection and cardiovascular events. Risk factors for adverse clinical outcomes include pre-existent comorbidities, the introduction of an immunodeficient status and (lack of) lifestyle changes after transplantation. Indeed, physical inactivity and poor physical fitness are important targets to address in order to improve clinical outcomes after kidney transplantation. This review summarizes the current evidence on exercise training after kidney transplantation, derived from randomized controlled trials. As much as possible, results are discussed in the perspective of the Standardized Outcomes in Nephrology-Transplantation core outcomes, which were recently described as critically important outcome domains for trials in kidney transplant recipients.

The Histological Picture of Indication Biopsies in the First 2 Weeks after Kidney Transplantation

BACKGROUND AND OBJECTIVES

In preclinical studies, ischemia-reperfusion injury and older donor age are associated with graft inflammation in the early phase after transplantation. In human kidney transplantation, impaired allograft function in the first days after transplantation is often adjudicated to donor- and procedure-related characteristics, such as donor age, donor type, and ischemia times.

DESIGN

, setting, participants, & measurementsIn a cohort of 984 kidney recipients, 329 indication biopsies were performed within the first 14 days after transplantation. The histologic picture of these biopsies and its relationship with alloimmune risk factors and donor- and procedure-related characteristics were studied, as well as the association with graft failure. Multivariable Cox models were applied to quantify the cause-specific hazard ratios for early rejection and early inflammatory scores, adjusted for potential confounders. For quantification of hazard ratios of early events for death-censored graft failure, landmark analyses starting from day 15 were used.

RESULTS

Early indication biopsy specimens displayed microvascular inflammation score ≥2 in 30% and tubulointerstitial inflammation score ≥2 in 49%. Rejection was diagnosed in 186 of 329 (57%) biopsies and associated with the presence of pretransplant donor-specific HLA antibodies and the number of HLA mismatches, but not nonimmune risk factors in multivariable Cox proportional hazards analysis. In multivariable Cox proportional hazards analysis, delayed graft function, the graft dysfunction that prompted an early indication biopsy, HLA mismatches, and pretransplant donor-specific HLA antibodies were significantly associated with a higher risk for death-censored graft failure, whereas early acute rejection was not.

CONCLUSIONS

Indication biopsies performed early after kidney transplantation display inflammatory changes related to alloimmune risk factors. Nonimmune risk factors for ischemia-reperfusion injury, such as cold and warm ischemia time, older donor age, and donor type, were not identified as strong risk factors for early inflammation after human kidney transplantation.

A rare case of hemodialysis-related portosystemic encephalopathy and review of the literature

Hemodialysis-related portosystemic encephalopathy (HRPSE) is a clinical phenomenon where portosystemic encephalopathy (PSE) develops without liver dysfunction, usually caused by changes in the portosystemic blood flow related to hemodialysis. We describe the case of a 22-year old patient with a transjugular intrahepatic portosystemic shunt (TIPS) who developed HRPSE several months after initiation of hemodialysis. Despite initial therapy with laxatives and neomycin symptoms recurred. It was only after relocation of the hemodialysis catheter from the superior caval vein to the femoral vein that symptoms completely resolved.

Markers of protein-energy wasting and physical performance in haemodialysis patients: A cross-sectional study

Background

Physical impairments are common in uraemia, as reflected by the high risk of falls of haemodialysis (HD) patients. Furthermore, these patients often suffer from malnutrition.

Objective

Up to now, it is unknown which aspects of physical performance are predominantly driven by malnutrition in HD patients. As this answer could steer different interventions, the aim of this study was to evaluate the cross-sectional relationship between nutritional status, muscle strength, exercise capacity and the risk of falls.

Methods

This study recruited HD patients between December 2016 and March 2018 from two hospital-based and five satellite dialysis units (registration number on clinicaltrial.gov: NCT03910426). The mini-nutritional assessment scale as well as objective measures of protein-energy wasting were obtained (total iron-binding capacity, total protein levels, and CRP). Physical assessment included muscle strength (quadriceps, handgrip force, and sit-to-stand test), exercise capacity (six-minute walking test) and the risk of falls (Tinetti, FICSIT, and dialysis fall index). Their interrelationship was analysed by ridge regression models.

Results

Out of 113 HD patients (mean age 67 years ± 16.1, 57.5% male) 36.3% were malnourished according to the mini-nutritional assessment scale and a majority had impaired quadriceps force (86.7%), six-minute walking test (92%), and an increased risk of falls (73.5%). Total protein and CRP levels were identified as relevant nutritional factors in the association with physical performance. Nutritional parameters explained 9.2% of the variance in the risk of falls and 7.6% of the variance in exercise capacity. No conclusive association was found between nutritional status and muscle strength.

Conclusion

Protein-energy wasting is a determinant of the risk of falls and exercise capacity in patients on HD. The association between malnutrition and muscle weakness remains inconclusive.

The screening score of Mini Nutritional Assessment (MNA) is a useful routine screening tool for malnutrition risk in patients on maintenance dialysis

PURPOSE

Malnutrition is prevalent in patients on dialysis and is associated with morbidity and mortality. Nutritional status can be assessed by a variety of biochemical and physical parameters or nutritional assessment scores. Most of these methods are expensive or cumbersome to use and are not suitable for routine repetitive follow-up in dialysis patients. The Mini Nutritional Assessment (MNA) has a short form screening set (MNA-SF), which would be suitable as a screening tool, but has not been validated yet in dialysis patients. We aimed to assess whether the MNA is an appropriate tool for identifying nutritional problems in dialysis patients.

METHOD

MNA, routine biochemistry, physical parameters, comorbidities were assessed in cross-sectional multicentric cohorts of hemodialysis and peritoneal dialysis patients with a longitudinal follow up of 2 years for mortality.

RESULTS

In this cohort of 216 patients, mortality was 27.3% at a follow up of 750±350 days. The mean MNA-SF score was 9.9±1.8, with 30.1%, 59.3% and 10.6% of patients categorized as having normal nutritional status, at risk for malnutrition and malnourished, respectively. The screening score was associated with mortality (HR 0.86, 95% CI 0.75-0.98 per point). With normal nutrition as reference, adjusted mortality was 2.50 (95% CI 1.16-5.37) and 3.89 (95% CI 1.48-10.13) for patients at risk for malnutrition and with malnutrition, respectively. After recalibrating the MNA full score for the specificity of some of its domains for dialysis patients, the MNA-SF had a good sensitivity and specificity for not being well nourished (0.95 and 0.63 respectively) in the full score, and a high negative predictive value (0.91).

CONCLUSION

The MNA-SF is independently associated with 2 year mortality in dialysis patients. It has a high negative predictive value for excluding being at risk or having malnutrition in the full score. Therefore, it can be advocated as a screening tool for nutritional status in dialysis patients.

Composite Uremic Load and Physical Performance in Hemodialysis Patients: A Cross-Sectional Study

Impaired physical performance is common in patients on hemodialysis (HD) and is associated with poor prognosis. A patient relevant marker of adequacy of dialysis is lacking. Previous studies evaluated uremic toxicity by assessing the impact of different uremic toxins separately. However, such an approach is most likely not reflective of true uremic toxicity. Therefore, this cross-sectional study aimed to examine if the uremic syndrome, estimated as one composite of different uremic toxins (facilitated by ridge regression method) to reflect the kinetic behavior during dialysis, is associated with physical performance in patients on HD. Levels of p-cresyl glucuronide and sulfate, indole-acetic acid, indoxyl sulfate, uric acid, hippuric acid, and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid were assessed and associated by ridge regression to muscle strength, functional exercise capacity, and measures of balance and coordination. 75 HD patients were included (mean age 68 years, 57% male). The composite of different uremic toxins (i.e., uremic load) explained 22% of the variance in handgrip strength. Although there was an association between full body muscle strength and the composite uremic load independent of nutritional status, age and gender, the predictive power of composite uremic load for muscle weakness is limited. Single uremic toxins as well as composite uremic load were not associated with exercise capacity, coordination, and balance, indicating that the degree of uremia does not predict physical performance in patients on HD.

Associations between the measures of physical function, risk of falls and the quality of life in haemodialysis patients: a cross-sectional study

BACKGROUND

Impaired physical function due to muscle weakness and exercise intolerance reduces the ability to perform activities of daily living in patients with end-stage kidney disease, and by consequence, Health-Related Quality of Life (HRQoL). Furthermore, the risk of falls is an aggregate of physical function and, therefore, could be associated with HRQoL as well. The present study examined the associations between objective and subjective measures of physical function, risk of falls and HRQoL in haemodialysis patients.

METHODS

This cross-sectional multicentre study included patients on maintenance haemodialysis. Physical function (quadriceps force, handgrip force, Sit-to-Stand, and six-minute walking test), the risk of falls (Tinetti, FICSIT-4, and dialysis fall index) and HRQoL (PROMIS-29 and EQ-5D-3 L) were measured and analysed descriptively, by general linear models and logistic regression.

RESULTS

Of the 113 haemodialysis patients (mean age 67.5 ± 16.1, 57.5% male) enrolled, a majority had impaired quadriceps force (86.7%) and six-minute walking test (92%), and an increased risk of falls (73.5%). Whereas muscle strength and exercise capacity were associated with global HRQoL (R² = 0.32) and the risk of falls, the risk of falls itself was related to psycho-social domains (R² = 0.11) such as depression and social participation, rather than to the physical domains of HRQoL. Objective measures of physical function were not associated with subjective fatigue, nor with subjective appreciation of health status.

CONCLUSIONS

More than muscle strength, lack of coordination and balance as witnessed by the risk of falls contribute to social isolation and HRQoL of haemodialysis patients. Mental fatigue was less common than expected, whereas, subjective and objective physical function were decreased.

154 compared to 54 mmol per liter of sodium in intravenous maintenance fluid therapy for adult patients undergoing major thoracic surgery (TOPMAST): a single-center randomized controlled double-blind trial

PURPOSE

To determine the effects of the sodium content of maintenance fluid therapy on cumulative fluid balance and electrolyte disorders.

METHODS

We performed a randomized controlled trial of adults undergoing major thoracic surgery, randomly assigned (1:1) to receive maintenance fluids containing 154 mmol/L (Na154) or 54 mmol/L (Na54) of sodium from the start of surgery until their discharge from the ICU, the occurrence of a serious adverse event or the third postoperative day at the latest. Investigators, caregivers and patients were blinded to the treatment. Primary outcome was cumulative fluid balance. Electrolyte disturbances were assessed as secondary endpoints, different adverse events and physiological markers as safety and exploratory endpoints.

FINDINGS

We randomly assigned 70 patients; primary outcome data were available for 33 and 34 patients in the Na54 and Na154 treatment arms, respectively. Estimated cumulative fluid balance at 72 h was 1369 mL (95% CI 601-2137) more positive in the Na154 arm (p < 0.001), despite comparable non-study fluid sources. Hyponatremia < 135 mmol/L was encountered in four patients (11.8%) under Na54 compared to none under Na154 (p = 0.04), but there was no significantly more hyponatremia < 130 mmol/L (1 versus 0; p = 0.31). There was more hyperchloremia > 109 mmol/L under Na154 (24/35 patients, 68.6%) than under Na54 (4/34 patients, 11.8%) (p < 0.001). The treating clinicians discontinued the study due to clinical or radiographic fluid overload in six patients receiving Na154 compared to one patient under Na54 (excess risk 14.2%; 95% CI - 0.2-30.4%, p = 0.05).

CONCLUSIONS

In adult surgical patients, sodium-rich maintenance solutions were associated with a more positive cumulative fluid balance and hyperchloremia; hypotonic fluids were associated with mild and asymptomatic hyponatremia.

Next-generation protein analysis in the pathology department

Traditionally, immunohistochemistry (IHC) is used by pathologists to localise specific proteins or peptides in tissue slides. In the era of personalised medicine, however, molecular tissue analysis becomes indispensable for correct diagnosis, prognosis and therapeutic decision, not only on the DNA or mRNA level but also on the protein level. Combining molecular information with imaging presents many advantages. Therefore, matrix-assisted laser desorption/ionisation imaging mass spectrometry (MALDI IMS) is a promising technique to be added to the armamentarium of the pathologist. Here, we focus on the workflow, advantages and drawbacks of both MALDI IMS and IHC. We also briefly discuss a few other protein imaging modalities and give examples of applications.

MicroRNAs in AKI and Kidney Transplantation

MicroRNAs are epigenetic regulators of gene expression at the posttranscriptional level. They are involved in intercellular communication and crosstalk between different organs. As key regulators of homeostasis, their dysregulation underlies several morbidities including kidney disease. Moreover, their remarkable stability in plasma and urine makes them attractive biomarkers. Beyond biomarker studies, clinical microRNA research in nephrology in recent decades has focused on the discovery of specific microRNA signatures and the identification of novel targets for therapy and/or disease prevention. However, much of this research has produced equivocal results and there is a need for standardization and confirmation in prospective trials. This review aims to provide an overview of general concepts and available clinical evidence in both the pathophysiology and biomarker fields for the role of microRNA in AKI and kidney transplantation.

The effects of aerobic exercise on eGFR, blood pressure and VO2peak in patients with chronic kidney disease stages 3-4: A systematic review and meta-analysis

BACKGROUND

CKD is associated with several comorbidities, cardiovascular disease being the most significant. Aerobic training has a beneficial effect on cardiovascular health in healthy and some well-defined non-healthy populations. However, the effect of aerobic training on glomerular filtration rate in patients with CKD stages 3-4 is unclear.

OBJECTIVE

To review the effects of aerobic exercise training on kidney and cardiovascular function in patients with chronic kidney disease (CKD) stages 3-4.

METHODS

A random-effects meta-analysis was performed to analyse published randomized controlled trials through February 2018 on the effect of aerobic training on estimated glomerular filtration rate, blood pressure and exercise tolerance in patients with CKD stages 3-4. Web of Science, PubMed and Embase databases were searched for eligible studies.

RESULTS

11 randomized controlled trials were selected including 362 participants in total. Favourable effects were observed on estimated glomerular filtration rate (+2.16 ml/min per 1.73m2; [0.18; 4.13]) and exercise tolerance (+2.39 ml/kg/min; [0.99; 3.79]) following an on average 35-week aerobic training program when compared to standard care. No difference in change in blood pressure was found.

CONCLUSIONS

There is a small beneficial effect of aerobic training on estimated glomerular filtration rate and exercise tolerance, but not on blood pressure, in patients with CKD stages 3-4. However, data are limited and pooled findings were rated as of low to moderate quality.

[Hereditary kidney disease in adolescents and adults]

In recent years, there has been a great deal of interest in the literature on genetic kidney disease. It has become clear that chronic kidney disease (CKD) may be caused by single gene mutations, not only in paediatric patients but also in adult patients. Studies indicate that pathogenic mutations can be found in approximately 10% of patients with CKD, and figures are still rising. Syndrome characteristics do not have to be present. In this article, we would like to draw attention on this aspect of a common health problem. We present three cases of genetic kidney disease from our daily practice, showing the value of a multidisciplinary approach for reaching a correct diagnosis. Additionally, we would like to emphasise the value of taking a familial history in every patient with renal disease.

Does Kidney Donor Risk Index implementation lead to the transplantation of more and higher-quality donor kidneys?

Background

The Kidney Donor Risk Index (KDRI) is a quantitative evaluation of the quality of donor organs and is implemented in the US allocation system. This single-centre study investigates whether the implementation of the KDRI in our decision-making process to accept or decline an offered deceased donor kidney, increases our acceptance rate.

Methods

From April 2015 until December 2016, we prospectively calculated the KDRI for all deceased donor kidney offers allocated by Eurotransplant to our centre. The number of the transplanted versus declined kidney offers during the study period were compared to a historical set of donor kidney offers.

Results

After implementation of the KDRI, 26.1% (75/288) of all offered donor kidneys were transplanted, compared with 20.7% (136/657) in the previous period (P < 0.001). The median KDRI of all transplanted donor kidneys during the second period was 0.97 [Kidney Donor Profile Index (KDPI) 47%], a value significantly higher than the median KDRI of 0.85 (KDPI 34%) during the first period (P = 0.047). A total of 68% of patients for whom a first-offered donor kidney was declined during this period were transplanted after a median waiting time of 386 days, mostly with a lower KDRI donor kidney.

Conclusions

Implementing the KDRI in our decision-making process increased the transplantation rate by 26%. The KDRI can be a supportive tool when considering whether to accept or decline a deceased donor kidney offer. More data are needed to validate this score in other European centres.

Introducing TOPMAST, the first double-blind randomized clinical trial specifically dedicated to perioperative maintenance fluid therapy in adults

BACKGROUND

Although prescribed to every patient undergoing surgery, maintenance fluid therapy is a poorly researched part of perioperative fluid therapy. The tonicity of the chosen solutions, could be an important cause of morbidity, with hyponatremia being a potential side effect of hypotonic solutions, where isotonic solution could lead to fluid overload.

METHODS

The TOPMAST-trial is an ongoing prospective single-center double-blind randomized trial comparing an isotonic and a hypotonic maintenance fluid strategy during and after surgery in patients undergoing different types of major thoracic surgery. Patients receive NaCl 0.9% in glucose 5% with an added 40 mmol L-1 of potassium chloride or a premixed solution containing 54 mmol L-1 sodium, 55 mmol L-1 chloride and 26 mmol of potassium at a rate of 27 mL per kg of body weight per day. The primary hypothesis is that isotonic maintenance solutions cause a more positive perioperative fluid balance than hypotonic fluids. Different secondary safety endpoints will be explored, especially the effect of the study treatments on the occurrence electrolyte disturbances (e.g. hyponatremia, hyperchloremia) and a set of clinical endpoints. Efficacy endpoints include the need for resuscitation fluids and assessment of renal and hormonal adaptive mechanisms. An anticipated 68 patients will be included between March 2017 and January 2018.

DISCUSSION

The study will provide the most comprehensive evaluation of clinically important outcomes associated with the choice of perioperative maintenance fluid therapy.

Prediction of delayed graft function using different scoring algorithms: A single-center experience

AIM

To compare the performance of 3 published delayed graft function (DGF) calculators that compute the theoretical risk of DGF for each patient.

METHODS

This single-center, retrospective study included 247 consecutive kidney transplants from a deceased donor. These kidney transplantations were performed at our institution between January 2003 and December 2012. We compared the occurrence of observed DGF in our cohort with the predicted DGF according to three different published calculators. The accuracy of the calculators was evaluated by means of the c-index (receiver operating characteristic curve).

RESULTS

DGF occurred in 15.3% of the transplants under study. The c index of the Irish calculator provided an area under the curve (AUC) of 0.69 indicating an acceptable level of prediction, in contrast to the poor performance of the Jeldres nomogram (AUC = 0.54) and the Chapal nomogram (AUC = 0.51). With the Irish algorithm the predicted DGF risk and the observed DGF probabilities were close. The mean calculated DGF risk was significantly different between DGF-positive and DGF-negative subjects (P < 0.0001). However, at the level of the individual patient the calculated risk of DGF overlapped very widely with ranges from 10% to 51% for recipients with DGF and from 4% to 56% for those without DGF. The sensitivity, specificity and positive predictive value of a calculated DGF risk ≥ 30% with the Irish nomogram were 32%, 91% and 38%.

CONCLUSION

Predictive models for DGF after kidney transplantation are performant in the population in which they were derived, but less so in external validations.

Failed Downregulation of Circulating MicroRNA-155 in the Early Phase after ST Elevation Myocardial Infarction Is Associated with Adverse Left Ventricular Remodeling

BACKGROUND

MicroRNA are noncoding RNA that have a significant role in both inflammatory and cardiovascular diseases.

AIMS

We aimed to assess whether the inflammation-related microRNA-155 is associated with the development of adverse left ventricular (LV) remodeling following ST elevation myocardial infarction (STEMI).

METHODS

Peripheral blood samples were collected in the inflammatory (day 2), proliferative (day 5), and maturation phases (6 months) after STEMI (n = 20). Granulocytes, monocytes, and lymphocytes were enumerated with flow cytometry. The changes in LV volumes were assessed with 3-D echocardiography on day 1 and after 6 months. Adverse remodeling was defined as a >20% increase in end-diastolic volume. Healthy subjects were recruited as controls.

RESULTS

MicroRNA-155 measured on day 5 correlated positively with the relative change in end-diastolic volume (ρ = 0.490, p = 0.028). MicroRNA-155 (day 5) was significantly higher in patients with compared to patients without adverse LV remodeling. The expression level was similar in healthy subjects (n = 8) and in patients with LV remodeling. There was a positive correlation between microRNA-155 and the amount of monocytes (day 5, ρ = 0.463, p = 0.046).

CONCLUSION

Impaired downregulation of microRNA-155 during the second phase of the post- STEMI inflammatory response is a determinant of the development of adverse LV remodeling.

Endothelial maintenance in health and disease: Importance of sex differences

The vascular endothelium has emerged as more than just an inert monolayer of cells lining the vascular bed. It represents the interface between the blood stream and vessel wall, and has a strategic role in regulating vascular homeostasis by the release of vasoactive substances. Endothelial dysfunction contributes to the development and progression of cardiovascular disease. Recognition of sex-specific factors implicated in endothelial cell biology is important for the identification of clinically relevant preventive and/or therapeutic strategies. This review aims to give an overview of the recent advances in understanding the importance of sex specific observations in endothelial maintenance, both in healthy and diseased conditions. The female endothelium is highlighted in the context of polycystic ovary syndrome and pre-eclampsia. Furthermore, sex differences are explored in chronic kidney disease, which is currently appreciated as one of public health priorities. Overall, this review endorses integration of sex analysis in experimental and patient-oriented research in the exciting field of vascular biology.

Impaired vascular function contributes to exercise intolerance in chronic kidney disease

BACKGROUND

Exercise intolerance is an important feature in patients with chronic kidney disease (CKD) and is prognostic for both increased morbidity and mortality. Little is known about the underlying mechanisms in predialysis CKD. This study aimed to gain more insight into the role of vascular dysfunction in the exercise intolerance of predialysis CKD. In addition, vascular-related microRNAs (miRNAs)-as epigenetic regulators of exercise capacity-were analysed.

METHODS

Sixty-three patients with CKD stages 1-5 and 18 healthy controls were included. Peak oxygen consumption (VO₂peak) was determined by cardiopulmonary exercise testing, endothelial function by flow-mediated dilation (FMD) and arterial stiffness by carotid-femoral pulse wave velocity (PWV). Plasma miRNA levels (miR-21, miR-126, miR-146a, miR-150 and miR-210) were quantified by quantitative RT-PCR.

RESULTS

VO₂peak was already impaired in mild CKD (stages 1-3A) and significantly correlated with estimated glomerular filtration rate (eGFR; r = 0.525, P < 0.001). Likewise, both FMD and PWV were significantly correlated with eGFR (r = 0.319, P = 0.007 and r = -0.365, P = 0.001, respectively). In multiple regression analysis, PWV remained one of the strongest independent determinants of VO₂peak (β = -0.301, P = 0.01). Of the studied miRNA, circulating levels of miR-146a and miR-150 correlated with eGFR, PWV and VO₂peak, but the association with the latter was lost when correcting for PWV.

CONCLUSIONS

Arterial stiffness contributes to the observed reduced aerobic capacity in predialysis CKD, independent of age, haemoglobin levels and endothelial function and represents a promising therapeutic target for improving exercise capacity in this population. Future work is required to elucidate why higher circulating levels of miR-146a and miR-150 are associated with impaired renal function and increased arterial stiffness.

Improving stem cell therapy in cardiovascular diseases: the potential role of microRNA

The initial promising prospect of autologous bone marrow-derived stem cell therapy in the setting of cardiovascular diseases has been overshadowed by functional shortcomings of the stem cell product. As powerful epigenetic regulators of (stem) cell function, microRNAs are valuable targets for novel therapeutic strategies. Indeed, modulation of specific miRNA expression could contribute to improved therapeutic efficacy of stem cell therapy. First, this review elaborates on the functional relevance of miRNA dysregulation in bone marrow-derived progenitor cells in different cardiovascular diseases. Next, we provide a comprehensive overview of the current evidence on the effect of specific miRNA modulation in several types of progenitor cells on cardiac and/or vascular regeneration. By elaborating on the cardioprotective regulation of progenitor cells on cardiac miRNAs, more insight in the underlying mechanisms of stem cell therapy is provided. Finally, some considerations are made regarding the potential of circulating miRNAs as regulators of the miRNA signature of progenitor cells in cardiovascular diseases.