MO363CHECKPOINT-INHIBITOR-ASSOCIATED ACUTE KIDNEY INJURY AND MORTALITY: AN OBSERVATIONAL STUDY

Background and Aims

Immune checkpoint inhibitors, approved for the treatment of various types of cancer, are known to cause a unique spectrum of autoimmune-related side effects, including acute kidney injury (AKI). The aim of this study was to describe the incidence, risk factors, renal outcomes, and mortality of AKI in patients receiving checkpoint inhibitors.

Method

Patients receiving checkpoint inhibitors between January 2013 and May 2020 were identified using the Utrecht Patient Oriented Database. AKI was defined as an increase in creatinine of ≥1.5 times the baseline value. Cox proportional hazard regression analysis was used to assess risk factors for AKI and to evaluate the relationship between AKI and mortality. Persistent kidney injury was diagnosed in AKI patients with a final creatinine measurement of >1.3 times the baseline value.

Results

Out of 676 patients receiving checkpoint inhibitors, AKI occurred in 96 (14.2%) patients. Chart review showed that AKI was checkpoint inhibitor-associated in 32 (4.7%) patients. Baseline variables associated with AKI were a primary gynecological malignancy (HR 3.91, 95% CI 1.55 to 9.85), treatment with checkpoint inhibitor ipilimumab (HR 2.31, 95% CI 1.03 to 5.20), and pre-existent use of a diuretic (HR 2.61, 95% CI 1.21 to 5.60), an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker (HR 2.49, 95% CI 1.10 to 5.60), and a proton pump inhibitor (HR 1.69, 95% CI 1.04 to 2.75). In 35.4% of the patients who had developed AKI, persistent kidney dysfunction was observed at the end of follow-up. Patients who developed AKI had a 2.13-fold (95% CI 1.58 to 2.87) increased mortality risk compared to patients who did not develop AKI. Mortality risk was not increased by checkpoint inhibitor-associated AKI (HR 1.11, 95% CI 0.64 to 1.92), but only by AKI related to other causes (HR 2.87, 95% CI 2.04 to 4.04).

Conclusion

Patients receiving checkpoint inhibitors frequently develop AKI, however, checkpoint inhibitor-associated AKI does not seem to increase mortality.

FC 069

Background and Aims

Chronic kidney disease (CKD) and atrial fibrillation (AF) are both risk factors for bleeding, stroke and mortality. Whether the combination of CKD and AF leads to higher risks of bleeding, stroke and mortality than CKD or AF alone is not known. The aim of our study was to investigate the interaction between CKD and AF and outcomes.

Method

We included 12,394 subjects referred to the University Medical Center Utrecht (the Netherlands) from September 1996 to February 2018f for an out-patient visit with classical risk factors for arterial disease or with symptomatic arterial disease (Utrecht Cardiovascular Cohort Second Manifestation of Arterial disease (UCC-SMART) cohort). Hazard ratios (HRs) with 95% confidence intervals (CIs) for bleeding, ischemic stroke or mortality were calculated with Cox proportional hazards analyses. Presence of additive interaction between AF and CKD was examined by calculating the relative excess risk due to interaction (RERI), the attributable proportion (AP) due to interaction and the synergy index (S).

Results

Of the 12,394 patients, 699 patients had AF, 2,752 patients had CKD and 325 patients had both AF and CKD. Overall, 382 patients developed a first bleeding event, 421 patients had a first ischemic stroke and 2203 patients died. Patients with both CKD and AF had a 3.0-fold (95% CI 2.0-4.4) increased risk for bleeding, a 4.2-fold (95% CI 3.0-6.0) increased ischemic stroke risk and a 2.2-fold (95% CI 1.9-2.6) increased mortality risk after adjustment as compared with subjects without AF and CKD (Table 1). Although bleeding and mortality risks were highest for the combination of AF and CKD, we did not find interaction between AF and CKD. However, we found an interaction between AF and CKD for ischemic stroke risk (RERI 1.88 (95% CI 0.31-3.46), AP 0.45 (95% CI 0.17-0.72) and S 2.40 (95% CI 1.08-5.32)) (Table 1).

Conclusion

The combination of CKD and AF is associated with high risks for bleeding, ischemic stroke and mortality. There is a positive interaction between AF and CKD for ischemic stroke risk, but not for bleeding or mortality.

MO446THE ASSOCIATION BETWEEN RENAL FUNCTION AND LEFT VENTRICULAR DIASTOLIC DYSFUNCTION AND HEART FAILURE WITH PRESERVED EJECTION FRACTION

Background and Aims

Impaired kidney function increase the risk of cardiovascular disease. However, it remains unclear whether this crosstalk between organs already exists at early stages in the disease trajectory and whether this risk varies with age and other factors. We aim to investigate the association between renal dysfunction and early structural and functional cardiac abnormalities in a cohort of participants referred to a cardiology outpatient department.

Method

We included participants from HELPFul (i.e. HEart failure with Preserved ejection Fraction in patients at risk for cardiovascular disease), a case-cohort study at Dutch cardiology outpatient clinics, who were aged 45 years and older without history of cardiovascular disease. A random sample of participants enriched with cases (defined as an early filling (E) to early diastolic mitral annular velocity (e’) (E/e’) ratio of ≥8 measured with echocardiography) was included in our study. Routine care measurements, including echocardiography and laboratory testing at the outpatient clinic were collected for all participants. An expert panel decided on presence or absence of heart failure with preserved ejection fraction (HFpEF), and left ventricular diastolic dysfunction (LVDD), guided by available international guidelines. The association between renal function, in terms of estimated glomerular filtration rate (eGFR) categories, and diagnosis of HFpEF and LVDD was assessed with multivariable logistic regression analyses, adjusted for cardiovascular and lifestyle risk factors. The association between renal function, in terms of creatinine and cystatin C levels, and echocardiographic parameters, including E/e’ ratio, LAVI (Left atrial volume index), LVMI (left ventricular mass index), and E/A (early (E) to late (A) ventricular filling ratio, was assessed with multivariable linear regression analyses, adjusted for age, sex, cardiovascular and lifestyle risk factors. Adjusted odds ratios (OR) were reported and the corresponding 95% confidence interval (95%CI).

Results

777 participants were included, mean age 62.9 (SD: 9.3) years, 67.3% were female. Hundred and fifty-six (20.1%) participants had mild renal dysfunction (eGFR: 60-89 ml/min/1.73 m2), and 24 (3.1%) moderate renal dysfunction (eGFR: 30-59 ml/min/1.73 m2). HFpEF and LVDD was more common in participants with moderate renal dysfunction (13% and 33%, respectively) than in those with normal renal function (6% and 16%, respectively). In the multivariable regression model. participants with both mild and moderate renal dysfunction had a higher likelihood of being diagnosed with HFpEF (OR: 2.82, 95%CI: 1.32 to 5.91; and OR: 5.37, 95%CI: 1.11 to 19.88, respectively), LVDD (OR: 2.08, 95%CI: 1.28 to 3.36; and OR: 2.92, 95%CI: 1.04 to 7.55, respectively), compared with participants with a normal renal function. However, no significant association between creatinine or cystatin C with E/e’, LAVI, LVMI, and E/A ratio was found after adjustment for age, sex, and cardiovascular risk and lifestyle factors.

Conclusion

Mild renal dysfunction is related to both LVDD and HFpEF, however, this might be partly explained by a higher age in patients with renal dysfunction. Further studies are warranted to determine if preventive cardiac treatment in patients with early renal dysfunction will benefit clinical outcomes.

A Perspective on a Urine-Derived Kidney Tubuloid Biobank from Patients with Hereditary Tubulopathies

Inherited kidney tubulopathies comprise a group of rare diseases with a significant societal impact, as lifelong treatment is often required and no therapies are available to prevent progression of renal damage. Diagnosis of inherited tubulopathies has improved with the advances of next generation sequencing. However, difficulties remain, such as a lack of genotype-phenotype correlation and unknown pathogenicity of newly identified variants. In addition, treatment remains mainly symptomatic. Both diagnosis and treatment can be improved by addition of in vitro functional studies to clinical care. Urine-derived kidney organoids ("tubuloids") are a promising platform for these studies. International collections of patient-derived tubuloids in a living biobank offer additional advantages for drug development and pathophysiological studies. In this review, we discuss how diagnosis and treatment of tubulopathies can be improved by in vitro studies using a tubuloid biobank. We also address practical challenges in the development of such biobank. Impact statement This review provides readers insight into aspects related to diagnosis and treatment of hereditary kidney tubulopathies that can be improved. In addition, it explains why in vitro functional analyses using a kidney organoid model (tubuloids) may be useful as a method to improve these aspects. Finally, the additional advantages and practical hurdles of collecting tubuloid lines in a biobank are discussed.

Abstract IA27: Patient-derived organoids in pediatric cancer research

Recent advances in in vitro culture technologies, such as adult stem cell-derived organoids, have opened up new avenues for the development of novel, more physiologic human cancer models. Such preclinical models are essential for efficient translation of basic cancer research into novel treatment regimens. We succeeded in growing organoids from a range of pediatric solid tumors, including Wilms’ tumors, renal cell carcinomas, and different types of rhabdoid tumors (i.e., AT/RT, MRT). Tumor organoids retain many characteristics of parental tumor tissue. For instance, Wilms’ tumor organoids retain the cellular heterogeneity of tumors, as they are composed of an intricate network of different cell types. Moreover, we demonstrate that tumor organoids are amenable to gene editing and high-throughput drug screens. In conclusion, our pediatric cancer organoids capture disease and tissue heterogeneity and provide a platform for basic cancer research, drug screening, and personalized medicine.

Citation Format: Camilla Calandrini, Frans Schutgens, Rurika Oka, Thanasis Margaritis, Tito Candelli, Luka Mathijsen, Carola Ammerlaan, Ravian van Ineveld, Sepideh Derakhshan, Lars Custers, Philip Lijnzaad, Harry Begthel, Hinri Kerstens, Maarten Rookmaker, Marianne Verhaar, Patrick Kemmeren, Ronald de Krijger, Kathy Pritchard-Jones, Anne Rios, Marry van den Heuvel-Eibrink, Frank Holstege, Ruben van Boxtel, Hans Clevers, Jarno Drost. Patient-derived organoids in pediatric cancer research [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr IA27.

P0810DOSAGE REDUCTION OF LOW MOLECULAR WEIGHT HEPARIN IN PATIENTS WITH RENAL DYSFUNCTION: EFFECTS ON ANTI-XA LEVELS AND CLINICAL OUTCOMES

Background and Aims

To prevent bio-accumulation of low molecular weight heparins (LMWHs) in patients with an impaired kidney function, guidelines recommend dosage reduction and anti-Xa monitoring. The aim of this study was to investigate the effect of pre-emptive dosage reduction of LMWH on anti-Xa levels. Furthermore, we investigated the association between anti-Xa levels and bleeding, thrombotic events and mortality.

Method

In this single center study, we followed 499 patients with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73m2 in whom anti-Xa levels were measured. We observed how many patients had anti-Xa levels that fell within the target range (between 1.0 U/ml and 2.0 U/ml with once daily LMWH and between 0.6 U/ml and 1.0 U/ml with twice daily LMWH), with a standard protocol of a pre-emptive dosage reduction of LMWH (25% reduction in patients with an eGFR between 30 and 60 ml/min/1.73m2 and a reduction of 50% in in patients with an eGFR below the 30 ml/min/1.73m2).

Furthermore, Cox proportional hazard analyses were used to estimate hazard ratios with 95% confidence intervals (CIs) to investigate the association between anti-Xa levels and major bleeding, thrombotic events (ischemic stroke or venous thrombosis) and mortality within three months of follow-up. Hazard ratios were adjusted for age, sex, body mass index, type of LMWH, once or twice daily dosing, antiplatelet drug use, indication for anticoagulation, comorbidities, hemoglobin concentration and eGFR.

Results

In a cohort of 499 patients (445 dalteparin and 54 nadroparin users), the median anti-Xa level was 0.44 U/ml (IQR 0.21-0.75) for the total group (n=499). A pre-emptive dosage reduction of LMWH led to adequate levels of anti-Xa in only 19% of the patients (12% for the dalteparin users and 50% for nadroparin users).

Of the 499 patients, 104 patients had a major bleeding, 27 had a thrombotic event and 146 died within three months. We did not find an association between anti-Xa levels and bleeding or mortality (Table 1). An anti-Xa level below the target range was associated with a non-significant increased risk estimate for thrombosis (HR 2.5, 95% CI 0.7-8.8) after adjustment (Table 1).

Conclusion

Pre-emptive dosage reduction of LMWH leads to low anti-Xa levels in a large proportion of patients and may lead to an undertreatment of patients with an impaired kidney function.

An organoid biobank for childhood kidney cancers that captures disease and tissue heterogeneity

Kidney tumours are among the most common solid tumours in children, comprising distinct subtypes differing in many aspects, including cell-of-origin, genetics, and pathology. Pre-clinical cell models capturing the disease heterogeneity are currently lacking. Here, we describe the first paediatric cancer organoid biobank. It contains tumour and matching normal kidney organoids from over 50 children with different subtypes of kidney cancer, including Wilms tumours, malignant rhabdoid tumours, renal cell carcinomas, and congenital mesoblastic nephromas. Paediatric kidney tumour organoids retain key properties of native tumours, useful for revealing patient-specific drug sensitivities. Using single cell RNA-sequencing and high resolution 3D imaging, we further demonstrate that organoid cultures derived from Wilms tumours consist of multiple different cell types, including epithelial, stromal and blastemal-like cells. Our organoid biobank captures the heterogeneity of paediatric kidney tumours, providing a representative collection of well-characterised models for basic cancer research, drug-screening and personalised medicine.

Pre-clinical cell culture models capturing the heterogeneity of childhood kidney tumours are limited. Here, the authors establish and characterise an organoid biobank of tumour and matched normal organoid cultures from over 50 children with different subtypes of kidney cancer.

Impaired kidney function is associated with intraplaque hemorrhage in patients undergoing carotid endarterectomy

BACKGROUND AND AIMS

Previously, we showed that patients undergoing carotid endarterectomy have an increased risk for major atherosclerotic events in the presence of moderate or poor kidney function. Acceleration of vascular inflammatory responses is considered to be causally involved in progression of atherogenesis and poor outcome in chronic kidney disease patients. The association between kidney function and plaque composition has not been thoroughly investigated yet. The aim of this study was to investigate the association between kidney function and atherosclerotic plaque composition in patients undergoing carotid endarterectomy.

METHODS

Atherosclerotic plaques, harvested from 1796 patients who underwent carotid endarterectomy, were immunohistochemically stained for macrophages, smooth muscle cells, calcifications, collagen, microvessels, lipid core size and intraplaque hemorrhage. Cytokines were measured in plaque and plasma and associated with kidney function. Quantitative proteomics were performed on 40 carotid plaques and associated with kidney function.

RESULTS

Decreased kidney function was associated with increased odds ratio of intraplaque hemorrhage, OR 1.15 (95% CI; 1.02-1.29 (p = 0.024)) and increased odds ratio of fibrous-atheromatous plaques (plaques with lipid core presenting more than 10% of total plaque surface) OR 1.21 (95% CI; 1.07-1.38 (p = 0.003)) per decrease of 20 points in eGFR. Proteomics revealed that decreased kidney function was associated with upregulation of the classical pathway of the complement system and the intrinsic pathway of the coagulation system.

CONCLUSIONS

Decreased kidney function was associated with plaque hemorrhage but not with inflammatory plaque characteristics. Our data suggests that other pathways than the inflammation-pathway are involved in plaque vulnerability and poor outcome in patients with decreased kidney function.

How can we reduce costs of solid-phase multiplex-bead assays used to determine anti-HLA antibodies?

Solid-phase multiplex-bead assays are widely used in transplantation to detect anti-human leukocyte antigen (HLA) antibodies. These assays enable high resolution detection of low levels of HLA antibodies. However, multiplex-bead assays are costly and yield variable measurements that limit the comparison of results between laboratories. In the context of a Dutch national Consortium study we aimed to determine the inter-assay and inter-machine variability of multiplex-bead assays, and we assessed how to reduce the assay reagents costs. Fifteen sera containing a variety of HLA antibodies were used yielding in total 7092 median fluorescence intensities (MFI) values. The inter-assay and inter-machine mean absolute relative differences (MARD) of the screening assay were 12% and 13%, respectively. The single antigen bead (SAB) inter-assay MARD was comparable, but showed a higher lot-to-lot variability. Reduction of screening assay reagents to 50% or 40% of manufacturers' recommendations resulted in MFI values comparable to 100% of the reagents, with an MARD of 12% or 14%, respectively. The MARD of the 50% and 40% SAB assay reagent reductions were 11% and 22%, respectively. From this study, we conclude that the reagents can be reliably reduced at least to 50% of manufacturers' recommendations with virtually no differences in HLA antibody assignments.

Abstract P1-10-09: Are patients with breast cancer undergoing adjuvant treatment able to follow an exercise program with a moderate to high intensity?

PURPOSE: We recently showed in a randomized trial, the Physical Activity during Cancer Treatment (PACT) study, that an 18-week exercise program reduced complaints of fatigue and improved physical fitness in newly diagnosed breast cancer patients undergoing adjuvant treatment. The beneficial effects were probably underestimated due to high levels of physical activity in the control group that received usual care only. Another possibility for dilution of the effect might be limited participation of the intervention group in the supervised exercise program or low compliance, i.e., an adjustment of the prescribed exercise protocol. We set out to study participation and compliance and to find determinants of reduced compliance.

METHODS: 102 patients in the PACT study were randomized into the intervention group that received a supervised exercise program 2 times a week for 18 weeks (36 sessions in total). Each session had a duration of 60 minutes and included a pre-specified period of aerobic interval exercises of specific intensities as well as muscle strength exercises. Sessions were supervised by physiotherapists, intensity was based on individual fitness characteristics and results were kept in a log.

We computed attendance (percentage of total sessions attended) and compliance (adherence to the prescribed duration and intensity of the aerobic part and to the muscle strength part of each attended session). We computed for each woman the percentage of sessions the women complied with the protocol, and report median percentages for compliance with the aerobic exercises, duration and intensity, and with the muscle strength exercises separately. Determinants of low compliance that were included in linear regression models were: age, behavioral, physical and psychosocial factors.

RESULTS: For 92 patients exercise logs were available. Patients were, on average, 50.2±7.8 years of age, all patients received chemotherapy and 70% received radiotherapy. Participation was high: patients participated in 83% (interquartile range 69-91%) of the sessions offered. Overall, also compliance was high: in 88% (63-97%) and 84% (65-94%) of all attended sessions patients were able to complete the aerobic (duration) and muscle strength program, respectively, as prescribed in the protocol. Compliance to the high-intensity part of the aerobic program was lower: in 50% (22-82%) of the sessions the intensity of the aerobic exercises was adjusted. Especially patients who received radiotherapy in addition to chemotherapy and patients who were more physically fatigued at baseline had a lower compliance to the high-intensity part of the aerobic exercises (β=-5.3 (confidence interval -9.4;-1.2) and β=-0.6 (-1.0;-0.1), respectively).

CONLUSIONS: Participation in and compliance to an 18-week aerobic and muscle strength exercise program was high. Thus, patients are well capable to exercise during adjuvant treatment for breast cancer. This study shows that preferably high intensity aerobic exercises were adjusted in a significant number of participants rather than the duration or the strength exercises. This has to be taken into account when developing training programs, especially in those patients who receive both, radiotherapy and chemotherapy.

Citation Format: May AM, Boer JH, Velthuis M, Steins Bisschop CN, Los M, Erdkamp F, ten Bokkel Huinink D, Bloemendal HJ, Rodenhuis C, de Roos MAJ, Verhaar M, van der Wall E, Peeters PHM. Are patients with breast cancer undergoing adjuvant treatment able to follow an exercise program with a moderate to high intensity?. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-09.

Nitric oxide production is reduced in patients with chronic renal failure

In patients with chronic renal failure (CRF), atherosclerosis is a major cause of cardiovascular morbidity and mortality. Generally, atherosclerosis has been associated with a reduced bioavailability of nitric oxide (NO). Experimental studies have indicated the presence of enhanced NO degradation by reactive oxygen species as well as decreased NO production as possible causes for this reduced NO bioavailability. So far, the question whether or not NO production is impaired in patients with CRF has never been investigated. Therefore, we measured whole body NO production in 7 patients with CRF, and in 7 matched healthy subjects. To assess the relative importance of a dysfunction of NO synthase (NOS), we compared the NO production of these patients to that of 2 other groups known to have endothelial dysfunction, ie, 7 patients with familial hypercholesterolemia (FH) who did not yet have signs of clinical cardiovascular disease (all nonsmokers), and 5 cigarette smokers. These groups were also compared with 7 nonsmoking, age-matched healthy subjects. Whole body NO production, determined as in vivo arginine-to-citrulline conversion, was assessed by giving an intravenous infusion of [15N2]-arginine as a substrate for NOS and measuring isotopic plasma enrichment of [15N]-citrulline by LC-MS. NO production in the CRF patients (0.13+/-0.02 micromol. kg-1. h-1) was significantly lower (P<0.05) than in the corresponding control group (0.23+/-0.09 micromol. kg-1. h-1). NO production also tended to be lower in the FH patients (0.16+/-0.04 micromol. kg-1. h-1), but the difference with the corresponding control group did not reach significance (0.22+/-0.06 micromol. kg-1. h-1). In the group of smokers, NO production was similar to that in nonsmokers (0. 22+/-0.09 micromol. kg-1. h-1). In conclusion, it is demonstrated for the first time that basal whole body NO production is reduced in patients with CRF. This finding implies that therapeutic interventions to endothelial dysfunction in these patients should be primarily directed toward improvement of NO production. The finding of only a tendency toward reduction of NO production in patients with FH and the absence of a reduction in cigarette smokers suggests that other mechanisms such as enhanced NO degradation may be involved in the decrease of NO bioavailability in these groups.

Nonproteolytic "activation" of prorenin by active site-directed renin inhibitors as demonstrated by renin-specific monoclonal antibody

Incubation of human plasma prorenin (PR), the enzymatically inactive precursor of renin (EC 3.4.23.15), with a number of nonpeptide high-affinity active site-directed renin inhibitors induces a conformational change in PR, which was detected by a monoclonal antibody that reacts with active renin but not with native inactive PR. This conformational change also occurred when inactive PR was activated during exposure to low pH. Nonproteolytically acid-activated PR, and inhibitor-"activated" PR, as well as native PR, were retained on a blue Sepharose column, in contrast to proteolytically activated PR. Kinetic analysis of the activation of plasma prorenin by renin inhibitor (INH) indicated that native plasma contains an open intermediary form of prorenin, PRoi, in which the active site is exposed and which is in rapid equilibrium with the inactive closed form, PRc. PRoi reacts with inhibitor to form a reversible complex, PRoi.INH, which undergoes a conformational change resulting in a tight complex of a modified open form of prorenin, PRo, and the inhibitor, PRoi.INH-->PRo.INH. The PRoi-to-PRo conversion leads to the expression of an epitope on the renin part of the molecule that is recognized by a renin-specific monoclonal antibody. Presumably, PRo corresponds to the enzymatically active form of PR that is formed during exposure to low pH. Thus, it seems that the propeptide of PR interacts with the renin part of the molecule not only at or near the enzyme's active site but also at some distance from the active site. Interference with the first interaction by renin inhibitor leads to destabilization of the propeptide, by which the second interaction is disrupted and the enzyme assumes its active conformation. The results of this study may provide a model for substrate-mediated prorenin activation and increase the likelihood that enzymatically active prorenin is formed in vivo.