Five-year single-center analysis of cytomegalovirus viremia in kidney transplant recipients and possible implication for novel prophylactic therapy approaches

BACKGROUND

Cytomegalovirus (CMV) infections are a common complication after kidney transplantation (KTx) and negatively affecting patient outcome. Valganciclovir (VGC) prophylaxis is often limited by drug-induced side effects and dose reduction due to decline in kidney function.

METHOD

In the present study, episodes of CMV viremia in the first year after KTx in a cohort of 316 recipients were analyzed retrospectively to identify risk factors linked to persistent infections.

RESULTS

In the studied cohort, 18.7% of patients showed a high-risk (HR) constellation (D+/R-) for CMV infections. CMV viremia affected 22% of our cohort, with HR patients being the most affected cohort (44.1%). Within this group, most viremic events (65.3%) occurred while patients were still on prophylactic therapy, showing significantly higher viral loads and a longer duration compared to seropositive recipients.

CONCLUSION

The analysis at hand revealed that detection of viremia under ongoing antiviral prophylaxis bears an increased risk for sustained viral replication and antiviral drug resistance in HR patients. We identified low estimated glomerular filtration rate (eGFR) and lower dose VGC prophylaxis post-KTx as a risk factor for breakthrough infections in HR patients in our single center cohort. These patients might benefit from a closer CMV monitoring or novel prophylactic agents as letermovir.

DKK3 as a potential novel biomarker in patients with autosomal polycystic kidney disease

Backgound

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease, and leads to a steady loss of kidney function in adulthood. The variable course of the disease makes it necessary to identify the patients with rapid disease progression who will benefit the most from targeted therapies and interventions. Currently, magnetic resonance imaging-based volumetry of the kidney is the most commonly used tool for this purpose. Biomarkers that can be easily and quantitatively determined, which allow a prediction of the loss of kidney function, have not yet been established in clinical practice. The glycoprotein Dickkopf 3 (DKK3) which is secreted in the renal tubular epithelium upon stress and contributes to tubulointerstitial fibrosis via the Wnt signaling pathway, was recently described as a biomarker for estimating risk of kidney function loss, but has not been investigated for ADPKD. This study aimed to obtain a first insight into whether DKK3 may indeed improve outcome prediction in ADPKD in the future.

Methods

In 184 ADPKD patients from the AD(H)PKD registry and 47 healthy controls, the urinary DKK3 (uDKK3) levels were determined using ELISA. Multiple linear regression was used to examine the potential of these values in outcome prediction.

Results

ADPKD patients showed significantly higher uDKK3 values compared with the controls (mean 1970 ± 5287 vs 112 ± 134.7 pg/mg creatinine). Furthermore, there was a steady increase in uDKK3 with an increase in the Mayo class (A/B 1262 ± 2315 vs class D/E 3104 ± 7627 pg/mg creatinine), the best-established biomarker of progression in ADPKD. uDKK3 also correlated with estimated glomerular filtration rate (eGFR). Patients with PKD1 mutations show higher uDKK3 levels compared with PKD2 patients (PKD1: 2304 ± 5119; PKD2: 506.6 ± 526.8 pg/mg creatinine). Univariate linear regression showed uDKK3 as a significant predictor of future eGFR slope estimation. In multiple linear regression this effect was not significant in models also containing height-adjusted total kidney volume and/or eGFR. However, adding both copeptin levels and the interaction term between copeptin and uDKK3 to the model resulted in a significant predictive value of all these three variables and the highest R2 of all models examined (∼0.5).

Conclusion

uDKK3 shows a clear correlation with the Mayo classification in patients with ADPKD. uDKK3 levels correlated with kidney function, which could indicate that uDKK3 also predicts a disproportionate loss of renal function in this collective. Interestingly, we found an interaction between copeptin and uDKK3 in our prediction models and the best model containing both variables and their interaction term resulted in a fairly good explanation of variance in eGFR slope compared with previous models. Considering the limited number of patients in these analyses, future studies will be required to confirm the results. Nonetheless, uDKK3 appears to be an attractive candidate to improve outcome prediction of ADPKD in the future.

Feasibility and impact of ketogenic dietary interventions in polycystic kidney disease: KETO-ADPKD-a randomized controlled trial

Ketogenic dietary interventions (KDIs) are beneficial in animal models of autosomal-dominant polycystic kidney disease (ADPKD). KETO-ADPKD, an exploratory, randomized, controlled trial, is intended to provide clinical translation of these findings (NCT04680780). Sixty-six patients were randomized to a KDI arm (ketogenic diet [KD] or water fasting [WF]) or the control group. Both interventions induce significant ketogenesis on the basis of blood and breath acetone measurements. Ninety-five percent (KD) and 85% (WF) report the diet as feasible. KD leads to significant reductions in body fat and liver volume. Additionally, KD is associated with reduced kidney volume (not reaching statistical significance). Interestingly, the KD group exhibits improved kidney function at the end of treatment, while the control and WF groups show a progressive decline, as is typical in ADPKD. Safety-relevant events are largely mild, expected (initial flu-like symptoms associated with KD), and transient. Safety assessment is complemented by nuclear magnetic resonance (NMR) lipid profile analyses.

Copeptin in autosomal dominant polycystic kidney disease: real-world experiences from a large prospective cohort study

Background

The identification of new biomarkers in autosomal-dominant polycystic kidney disease (ADPKD) is crucial to improve and simplify prognostic assessment as a basis for patient selection for targeted therapies. Post hoc analyses of the TEMPO 3:4 study indicated that copeptin could be one of those biomarkers.

Methods

Copeptin was tested in serum samples from patients of the AD(H)PKD study. Serum copeptin levels were measured using a time-resolved amplified cryptate emission (TRACE)-based assay. In total, we collected 711 values from 389 patients without tolvaptan treatment and a total of 243 values (of which 64 were pre-tolvaptan) from 94 patients on tolvaptan. These were associated with rapid progression and disease-causing gene variants and their predictive capacity tested and compared with the Mayo Classification.

Results

As expected, copeptin levels showed a significant negative correlation with estimated glomerular filtration rate (eGFR). Measurements on tolvaptan showed significantly higher copeptin levels (9.871 pmol/L vs 23.90 pmol/L at 90/30 mg; P < .0001) in all chronic kidney disease stages. Linear regression models (n = 133) show that copeptin is an independent predictor of eGFR slope. A clinical model (including eGFR, age, gender, copeptin) was nearly as good (R2 = 0.1196) as our optimal model (including height-adjusted total kidney volume, eGFR, copeptin, R2 = 0.1256). Adding copeptin to the Mayo model improved future eGFR estimation.

Conclusion

Copeptin levels are associated with kidney function and independently explained future eGFR slopes. As expected, treatment with tolvaptan strongly increases copeptin levels.

Interaction Between Determinants Governing Urine Volume in Patients With ADPKD on Tolvaptan and its Impact on Quality of Life

Introduction

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent genetic cause of kidney failure. Tolvaptan, a vasopressin 2 receptor antagonist, is the first drug with proven disease-modifying activity. Long-term treatment adherence is crucial, but a considerable fraction of patients discontinue treatment, because of aquaretic side effects.

Methods

Twenty-four-hour urine was collected in 75 patients with ADPKD during up-titration of tolvaptan and, in combination with clinical characteristics, examined to identify factors influencing urine volume. Patient-reported outcomes were analyzed using the Short Form-12 (SF-12) and patient-reported outcomes questionnaires reporting micturition frequency and burden of urine volume.

Results

Initiation of therapy led to a large increase in urine volume followed by only minor further increase during up-dosing. Younger patients and patients with better kidney function experienced a larger relative rise. Twenty-four-hour urine osmolality dropped by about 50% after therapy initiation independently of dose, with a considerable proportion of patients achieving adequate suppression. Sodium and potassium intake turned out to be the only significant modifiable factors for urine volume after multivariate linear regression models, whereas age and weight could be identified as non-modifiable factors. No change in quality of life (QoL) was detected in relation to treatment or urine volume using SF-12 questionnaires, a finding that was further supported by the results of the patient-reported outcomes assessment.

Conclusion

This study provides an in-detail analysis of factors associated with the degree of polyuria on tolvaptan and puts them into the context of QoL. These findings will contribute to optimized patient counseling regarding this treatment option in ADPKD.

RESET-PKD: a pilot trial on short-term ketogenic interventions in autosomal dominant polycystic kidney disease

BACKGROUND

Ketogenic dietary interventions (KDI) have been shown to be effective in animal models of polycystic kidney disease (PKD), but data from clinical trials are lacking.

METHODS

Ten autosomal dominant PKD (ADPKD) patients with rapid disease progression were enrolled at visit V1 and initially maintained a carbohydrate-rich diet. At V2, patients entered one of the two KDI arms: a 3-day water fast (WF) or a 14-day ketogenic diet (KD). At V3, they resumed their normal diet for 3-6 weeks until V4. At each visit, magnetic resonance imaging kidney and liver volumetry was performed. Ketone bodies were evaluated to assess metabolic efficacy and questionnaires were used to determine feasibility.

RESULTS

All participants [KD n = 5, WF n = 5; age 39.8 ± 11.6 years; estimated glomerular filtration rate 82 ± 23.5 mL/min/1.73 m2; total kidney volume (TKV) 2224 ± 1156 mL] were classified as Mayo Class 1C-1E. Acetone levels in breath and beta-hydroxybutyrate (BHB) blood levels increased in both study arms (V1 to V2 average acetone: 2.7 ± 1.2 p.p.m., V2 to V3: 22.8 ± 11.9 p.p.m., P = .0006; V1 to V2 average BHB: 0.22 ± 0.08 mmol/L, V2 to V3: 1.88 ± 0.93 mmol/L, P = .0008). Nine of 10 patients reached a ketogenic state and 9/10 evaluated KDIs as feasible. TKV did not change during this trial. However, we found a significant impact on total liver volume (ΔTLV V2 to V3: -7.7%, P = .01), mediated by changes in its non-cystic fraction.

CONCLUSIONS

RESET-PKD demonstrates that short-term KDIs potently induce ketogenesis and are feasible for ADPKD patients in daily life. While TLV quickly changed upon the onset of ketogenesis, changes in TKV may require longer-term interventions.

Sodium evolution in hyponatraemia: a mixed effects model analysis of the hyponatraemia registry

OBJECTIVE

Achieving recommended targets of sodium correction is challenging to physicians treating hyponatraemia. Plasma sodium has to be increased effectively, yet overcorrection must be prevented. This is often hampered by a high variability of responses to treatment. Here, we sought to delineate factors influencing sodium evolution.

DESIGN

We retrospectively analysed 3,460 patients from the multinational Hyponatraemia Registry comprising a wide range of hyponatraemia aetiologies and treatment strategies.

METHODS

Multivariable linear mixed effects models were applied to identify predictors of plasma sodium evolution within the first 24 hours of treatment.

RESULTS

Evolution of sodium levels over time showed a curvilinear pattern with steeper rise at earlier timepoints. Baseline sodium showed the most pronounced impact with an additional increment of 3.12 mEq/L for every 10 mEq/L initial sodium reduction. With sodium increments of 1.9 mEq/L and 1.4 mEq/L per 24 hours, respectively, the entities hypovolaemic and thiazide-associated hyponatraemia were independent factors for sodium evolution. Therapeutic regimens using hypertonic saline (4.6 mEq/L/24 h), tolvaptan (3.4 mEq/L/24 h), or combination therapy (2.6 mEq/L/24 h) were also associated with a significantly larger sodium rise when compared with no active treatment.

CONCLUSIONS

Choice and dosing of active hyponatraemia therapy should be adjusted not only according to aetiology but most importantly to pre-treatment sodium. Although counterintuitive, less aggressive therapy in more profound hyponatraemia might be safer but yet effective at least in less severe cases.

Organ Protection by Caloric Restriction Depends on Activation of the De Novo NAD+ Synthesis Pathway

SIGNIFICANCE STATEMENT

AKI is a major clinical complication leading to high mortality, but intensive research over the past decades has not led to targeted preventive or therapeutic measures. In rodent models, caloric restriction (CR) and transient hypoxia significantly prevent AKI and a recent comparative transcriptome analysis of murine kidneys identified kynureninase (KYNU) as a shared downstream target. The present work shows that KYNU strongly contributes to CR-mediated protection as a key player in the de novo nicotinamide adenine dinucleotide biosynthesis pathway. Importantly, the link between CR and NAD+ biosynthesis could be recapitulated in a human cohort.

BACKGROUND

Clinical practice lacks strategies to treat AKI. Interestingly, preconditioning by hypoxia and caloric restriction (CR) is highly protective in rodent AKI models. However, the underlying molecular mechanisms of this process are unknown.

METHODS

Kynureninase (KYNU) knockout mice were generated by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and comparative transcriptome, proteome and metabolite analyses of murine kidneys pre- and post-ischemia-reperfusion injury in the context of CR or ad libitum diet were performed. In addition, acetyl-lysin enrichment and mass spectrometry were used to assess protein acetylation.

RESULTS

We identified KYNU as a downstream target of CR and show that KYNU strongly contributes to the protective effect of CR. The KYNU-dependent de novo nicotinamide adenine dinucleotide (NAD+) biosynthesis pathway is necessary for CR-associated maintenance of NAD+ levels. This finding is associated with reduced protein acetylation in CR-treated animals, specifically affecting enzymes in energy metabolism. Importantly, the effect of CR on de novo NAD+ biosynthesis pathway metabolites can be recapitulated in humans.

CONCLUSIONS

CR induces the de novo NAD+ synthesis pathway in the context of IRI and is essential for its full nephroprotective potential. Differential protein acetylation may be the molecular mechanism underlying the relationship of NAD+, CR, and nephroprotection.

Repetitive administration of rituximab can achieve and maintain clinical remission in patients with MCD or FSGS

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are glomerulopathies associated with nephrotic syndrome. Primary forms of these diseases are treated with various regimes of immunosuppression. Frequently relapsing or glucocorticoid-dependent courses remain challenging. Here, a B-cell-depleting strategy with rituximab represents a salvage option although data are sparse in the adult population. In particular, there is limited evidence on the efficacy of restoring remission after initial successful treatment with rituximab and whether patients benefit from an individualized, relapse-based approach. We identified 13 patients who received multiple therapies with rituximab from the FOrMe-registry (NCT03949972), a nationwide registry for MCD and FSGS in Germany, or from the University Hospital of Cologne. Disease status, changes in serum creatinine, proteinuria, and time to relapse were evaluated. Relapse-free survival was compared to the patients' previous therapy regimens. Through all treatment cycles, an improvement of disease activity was shown leading to a complete remission in 72% and partial remission in 26% after 3 ([Formula: see text]0.001) and 6 months ([Formula: see text]0.001). Relapse-free survival increased from 4.5 months (95%-CI 3-10 months) to 21 months (95%-CI 16-32 months) ([Formula: see text]0.001) compared to previous immunosuppression regimens with no loss in estimated glomerular filtration over time (p = 0.53). Compared to continuous B-cell depletion, an individualized relapse-based approach led to a reduced rituximab exposure and significant cost savings. Relapse-based administration of rituximab in patients with MCD/FSGS with an initial good clinical response did not result in a decreased efficacy at a median follow-up duration of 110 months. Thus, reinduction therapies may provide an alternative to continuous B-cell-depletion and reduce the long-term side effects of continuous immunosuppression.

A Low-Cost Sequencing Platform for Rapid Genotyping in ADPKD and its Impact on Clinical Care

Introduction

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common genetic cause of kidney failure. Because of the heterogeneity in disease progression in ADPKD, parameters predicting future outcome are important. The disease-causing genetic variant is one of these parameters.

Methods

A multiplex polymerase chain reaction (PCR)-based panel (MPP) was established for analysis of 6 polycystic kidney disease (PKD) genes (PKD1, PKD2, HNF1B, GANAB, DZIP1L, and PKHD1) in 441 patients with ADPKD. Selected patients were additionally sequenced using Sanger sequencing or a custom enrichment-based gene panel. Results were combined with clinical characteristics to assess the impact of genetic data on clinical decision-making. Variants of unclear significance (VUS) were considered diagnostic based on a classic ADPKD clinical phenotype.

Results

Using the MPP, disease-causing variants were detected in 65.3% of patients. Sanger sequencing and the custom gene panel in 32 patients who were MPP-negative revealed 20 variants missed by MPP, (estimated overall false negative rate 24.6%, false-positive rate 9.4%). Combining clinical and genetic data revealed that knowledge of the genotype could have impacted the treatment decision in 8.2% of patients with a molecular genetic diagnosis. Sequencing only the PKD1 pseudogene homologous region in MPP-negative patients resulted in an acceptable false-negative rate of 3.28%.

Conclusion

The MPP yields rapid genotype information at lower costs and allows for simple extension of the panel for new disease genes. Additional sequencing of the PKD1 pseudogene homologous region is required in negative cases. Access to genotype information even in settings with limited resources is important to allow for optimal patient counseling in ADPKD.

Impact of first-line use of caplacizumab on treatment outcomes in immune thrombotic thrombocytopenic purpura

BACKGROUND

The von Willebrand factor-directed nanobody caplacizumab has greatly changed the treatment of immune thrombotic thrombocytopenic purpura (iTTP) in recent years. Data from randomized controlled trials established efficacy and safety.

OBJECTIVES

This study aims to address open questions regarding patient selection, tailoring of therapy duration, obstacles in prescribing caplacizumab in iTTP, effect on adjunct treatment, and outcomes in the real-world setting.

METHODS

We report retrospective, observational cohorts of 113 iTTP episodes treated with caplacizumab and 119 historical control episodes treated without caplacizumab. We aggregated data from the caplacizumab phase II/III trials and real-world data from France, the United Kingdom, Germany, and Austria (846 episodes, 396 treated with caplacizumab, and 450 historical controls).

RESULTS

Caplacizumab was efficacious in iTTP, independent of the timing of therapy initiation, but curtailed the time of active iTTP only when used in the first-line therapy within 72 hours after diagnosis and until at least partial ADAMTS13-activity remission. Aggregated data from multiple study populations showed that caplacizumab use resulted in significant absolute risk reduction of 2.87% for iTTP-related mortality (number needed to treat 35) and a relative risk reduction of 59%.

CONCLUSION

Caplacizumab should be used in first line and until ADAMTS13-remission, lowers iTTP-related mortality and refractoriness, and decreases the number of daily plasma exchange and hospital stay. This trial is registered at www.

CLINICALTRIALS

gov as #NCT04985318.

Cardiac Manifestations in Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD): A Single-Center Study

Key Points

Cardiovascular disease—a key driver of morbidity in CKD—is common in patients with autosomal dominant polycystic kidney disease (ADPKD). Pathologic echocardiography findings, including valvular defects, aortic root dilation, and hypertrophy, are found in most patients with ADPKD. These findings correlate with parameters indicating disease progression in ADPKD. Echocardiography should be offered to all patients with ADPKD.

Background

ADPKD is the most common monogenetic kidney disease and results in kidney failure in >75% of affected individuals. As a systemic disorder, ADPKD is associated with a variety of extrarenal manifestations, including cardiac manifestations, that affect the majority of patients. We characterized the cardiac involvement in patients with ADPKD from the German AD(H)PKD registry and compared them with kidney donor candidates as controls.

Methods

In this single-center cohort study, we evaluated 141 patients with ADPKD (44.17±11.23 years) from the German AD(H)PKD registry and 60 kidney donor candidates (55.08±10.21 years). All patients underwent clinical examination, abdominal MRI, and transthoracic echocardiography.

Results

Of the patients with ADPKD, 65% showed hypertrophy of the left ventricle (as defined by an end-diastolic interventricular septal wall thickness [IVSd] >10 mm) compared with 55% in control patients. Mitral regurgitation was the most common finding among 54% of patients with ADPKD who exhibited valvular dysfunction, albeit mild in most patients. Interestingly, left ventricular ejection fraction (LV-EF) differed significantly between both groups, with higher values in patients with ADPKD (64%±6% versus 60%±6%), whereas other parameters, including IVSd, left ventricular end-diastolic diameter (LVEDD), tricuspid annular plane systolic excursion (TAPSE), and pressure gradients across the aortic and tricuspid valve were similar between groups. Correlations of echocardiographic parameters with markers of disease progression revealed statistically significant associations for aortic root diameter (P =0.01), the pressure gradient across the aortic valve (AV dPmax; P =0.0003), and IVSd (P =0.0001), indicating rapid kidney disease progression may also be associated with cardiac findings.

Conclusion

Cardiovascular abnormalities are prevalent in patients with ADPKD. Considering the importance of cardiovascular disease for outcomes in CKD, early management and possibly prevention are important goals of any treatment scheme. Consequently, echocardiography should be offered to all patients with ADPKD in routine management.

Introduction of laparoscopic nephrectomy for autosomal dominant polycystic kidney disease as the standard procedure

PURPOSE

Autosomal dominant polycystic kidney disease (ADPKD) is a common hereditary disorder and accounts for 5-10% of all cases of kidney failure. 50% of ADPKD patients reach kidney failure by the age of 58 years requiring dialysis or transplantation. Nephrectomy is performed in up to 20% of patients due to compressive symptoms, renal-related complications or in preparation for kidney transplantation. However, due to the large kidney size in ADPKD, nephrectomy can come with a considerable burden. Here we evaluate our institution's experience of laparoscopic nephrectomy (LN) as an alternative to open nephrectomy (ON) for ADPKD patients.

MATERIALS AND METHODS

We report the results of the first 12 consecutive LN for ADPKD from August 2020 to August 2021 in our institution. These results were compared with the 12 most recent performed ON for ADPKD at the same institution (09/2017 to 07/2020). Intra- and postoperative parameters were collected and analyzed. Health related quality of life (HRQoL) was assessed using the SF36 questionnaire.

RESULTS

Age, sex, and median preoperative kidney volumes were not significantly different between the two analyzed groups. Intraoperative estimated blood loss was significantly less in the laparoscopic group (33 ml (0-200 ml)) in comparison to the open group (186 ml (0-800 ml)) and postoperative need for blood transfusion was significantly reduced in the laparoscopic group (p = 0.0462). Operative time was significantly longer if LN was performed (158 min (85-227 min)) compared to the open procedure (107 min (56-174 min)) (p = 0.0079). In both groups one postoperative complication Clavien Dindo ≥ 3 occurred with the need of revision surgery. SF36 HRQol questionnaire revealed excellent postoperative quality of life after LN.

CONCLUSION

LN in ADPKD patients is a safe and effective operative procedure independent of kidney size with excellent postoperative outcomes and benefits of minimally invasive surgery. Compared with the open procedure patients profit from significantly less need for transfusion with comparable postoperative complication rates. However significant longer operation times need to be taken in account.

Automated Kidney and Liver Segmentation in MR Images in Patients with Autosomal Dominant Polycystic Kidney Disease: A Multicenter Study

Background

Imaging-based total kidney volume (TKV) and total liver volume (TLV) are major prognostic factors in autosomal dominant polycystic kidney disease (ADPKD) and end points for clinical trials. However, volumetry is time consuming and reader dependent in clinical practice. Our aim was to develop a fully automated method for joint kidney and liver segmentation in magnetic resonance imaging (MRI) and to evaluate its performance in a multisequence, multicenter setting.

Methods

The convolutional neural network was trained on a large multicenter dataset consisting of 992 MRI scans of 327 patients. Manual segmentation delivered ground-truth labels. The model's performance was evaluated in a separate test dataset of 93 patients (350 MRI scans) as well as a heterogeneous external dataset of 831 MRI scans from 323 patients.

Results

The segmentation model yielded excellent performance, achieving a median per study Dice coefficient of 0.92-0.97 for the kidneys and 0.96 for the liver. Automatically computed TKV correlated highly with manual measurements (intraclass correlation coefficient [ICC]: 0.996-0.999) with low bias and high precision (-0.2%±4% for axial images and 0.5%±4% for coronal images). TLV estimation showed an ICC of 0.999 and bias/precision of -0.5%±3%. For the external dataset, the automated TKV demonstrated bias and precision of -1%±7%.

Conclusions

Our deep learning model enabled accurate segmentation of kidneys and liver and objective assessment of TKV and TLV. Importantly, this approach was validated with axial and coronal MRI scans from 40 different scanners, making implementation in clinical routine care feasible.Clinical Trial registry name and registration number: The German ADPKD Tolvaptan Treatment Registry (AD[H]PKD), NCT02497521.

Immune Response to Third and Fourth COVID-19 Vaccination in Hemodialysis Patients and Kidney Transplant Recipients

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a serious hazard for hemodialysis (HD) patients and kidney transplant (KTX) recipients as they suffer from an impaired immune response to SARS-CoV-2 vaccination. In addition, a definition of SARS-CoV-2 IgG titer that indicates a sufficient immune response, especially against new omicron variants, is urgently needed. In the present study, the immune response to either a third or a fourth dose of a mRNA vaccine was investigated in 309 dialysis and 36 KTX patients. SARS-CoV-2 IgG titer thresholds indicating neutralizing activity against wild type (WT) and the omicron variant BA.1 were quantified. After four vaccine doses, a high-neutralizing activity against WT was evidenced in HD patients, whereas the neutralizing rate against BA.1 was significant lower. Concerning KTX recipients, humoral and cellular immune responses after a third vaccination were still highly impaired. This calls for modified omicron-targeting vaccines.

Microvascular perfusion, perfused boundary region and glycocalyx shedding in patients with autosomal dominant polycystic kidney disease: results from the GlycoScore III study

Background

Vascular abnormalities and endothelial dysfunction are part of the spectrum of autosomal dominant polycystic kidney disease (ADPKD). The mechanisms behind these manifestations, including potential effects on the endothelial surface layer (ESL) and glycocalyx integrity, remain unknown.

Methods

Forty-five ambulatory adult patients with ADPKD were enrolled in this prospective, observational, cross-sectional, single-centre study. Fifty-one healthy volunteers served as a control group. All participants underwent real-time microvascular perfusion measurements of the sublingual microcirculation using sidestream dark field imaging. After image acquisition, the perfused boundary region (PBR), an inverse parameter for red blood cell (RBC) penetration into the ESL, was automatically calculated. Microvascular perfusion was assessed by RBC filling and capillary density. Concentrations of circulating glycocalyx components were determined by enzyme-linked immunosorbent assay.

Results

ADPKD patients showed a significantly larger PBR compared with healthy controls (2.09 ± 0.23 µm versus 1.79 ± 0.25 µm; P < .001). This was accompanied by significantly lower RBC filling (70.4 ± 5.0% versus 77.9 ± 5.4%; P < .001) as well as a higher valid capillary density {318/mm² [interquartile range (IQR) 269-380] versus 273/mm² [230-327]; P = .007}. Significantly higher plasma concentrations of heparan sulphate (1625 ± 807 ng/ml versus 1329 ± 316 ng/ml; P = .034), hyaluronan (111 ng/ml [IQR 79-132] versus 92 ng/ml [82-98]; P = .042) and syndecan-1 were noted in ADPKD patients compared with healthy controls (35 ng/ml [IQR 27-57] versus 29 ng/ml [23-42]; P = .035).

Conclusions

Dimensions and integrity of the ESL are impaired in ADPKD patients. Increased capillary density may be a compensatory mechanism for vascular dysfunction to ensure sufficient tissue perfusion and oxygenation.

Preoperative Short-Term Restriction of Sulfur-Containing Amino Acid Intake for Prevention of Acute Kidney Injury After Cardiac Surgery: A Randomized, Controlled, Double-Blind, Translational Trial

Background Acute kidney injury (AKI) is a major risk factor for chronic kidney disease and increased mortality. Until now, no compelling preventive or therapeutic strategies have been identified. Dietary interventions have been proven highly effective in organ protection from ischemia reperfusion injury in mice and restricting dietary intake of sulfur-containing amino acids (SAA) seems to be instrumental in this regard. The UNICORN trial aimed to evaluate the protective impact of restricting SAA intake before cardiac surgery on incidence of AKI. Methods and Results In this single-center, randomized, controlled, double-blind trial, 115 patients were assigned to a SAA-reduced formula diet (LowS group) or a regular formula diet (control group) in a 1:1 ratio for 7 days before scheduled cardiac surgery. The primary end point was incidence of AKI within 72 hours after surgery, secondary end points included increase of serum creatinine at 24, 48, and 72 hours as well as safety parameters. Quantitative variables were analyzed with nonparametric methods, while categorical variables were evaluated by means of Chi-square or Fisher test. SAA intake in the group with SAA reduced formula diet was successfully reduced by 77% (group with SAA reduced formula diet, 7.37[6.40-7.80] mg/kg per day versus control group, 32.33 [28.92-33.60] mg/kg per day, P<0.001) leading to significantly lower serum levels of methionine. No beneficial effects of SAA restriction on the rate of AKI after surgery could be observed (group with SAA reduced formula diet, 23% versus control group, 16%; P=0.38). Likewise, no differences were recorded with respect to secondary end points (AKI during hospitalization, creatinine at 24, 48, 72 hours after surgery) as well as in subgroup analysis focusing on age, sex, body mass index and diabetes. Conclusions SAA restriction was feasible in the clinical setting but was not associated with protective properties in AKI upon cardiac surgery. Registration URL: https://www.clinicaltrials.gov; Unique Identifier: NCT03715868.

A systematic analysis of diet-induced nephroprotection reveals overlapping changes in cysteine catabolism

Caloric Restriction (CR) extends lifespan and augments cellular stress-resistance from yeast to primates, making CR an attractive strategy for organ protection in the clinic. Translation of CR to patients is complex, due to problems regarding adherence, feasibility, and safety concerns in frail patients. Novel tailored dietary regimens, which modulate the dietary composition of macro- and micronutrients rather than reducing calorie intake promise similar protective effects and increased translatability. However, a direct head-to-head comparison to identify the most potent approach for organ protection, as well as overlapping metabolic consequences have not been performed. We systematically analyzed six dietary preconditioning protocols - fasting mimicking diet (FMD), ketogenic diet (KD), dietary restriction of branched chained amino acids (BCAA), two dietary regimens restricting sulfur-containing amino acids (SR80/100) and CR - in a rodent model of renal ischemia-reperfusion injury (IRI) to quantify diet-induced resilience in kidneys. Of the administered diets, FMD, SR80/100 and CR efficiently protect from kidney damage after IRI. Interestingly, these approaches show overlapping changes in oxidative and hydrogen sulfide (H₂S)-dependent cysteine catabolism as a potential common mechanism of organ protection.

MO016: Feasibility and Effectiveness of Short-Term Ketogenic Interventions in Autosomal Dominant Polycystic Kidney Disease (ADPKD): Results from the Reset-Pkd Study

BACKGROUND AND AIMS

Over the last years, there has been increasing evidence that defects in the energy metabolism of polycystic kidney disease (PKD) cyst lining cells, especially increased glucose dependency and defects in fatty acid oxidation, may underlie the pathogenesis of ADPKD, Rowe et al. (Defective glucose metabolism in polycystic kidney disease identifies a new therapeutic strategy. Nat Med 2013; 19(4): 488–493). Based on these data, ketogenic dietary interventions have effectively been used in PKD animal models, Kipp et al. (A mild reduction of food intake slows disease progression in an orthologous mouse model of polycystic kidney disease. Am J Physiol Renal Physiol 2016;310(8):F726-F31), Torres et al. (Ketosis ameliorates renal cyst growth in polycystic kidney disease. Cell Metab 2019;30(6):1007–23 e5) and Warner et al. (Food restriction ameliorates the development of polycystic kidney disease. J Am Soc Nephrol 2016;27(5):1437–1447). As a first-in-human pilot study, the RESET-PKD study now strives to translate these promising results in the clinical setting.

METHOD

The present study enrolled 10 ADPKD patients with rapid disease progression. After a screening visit (V1), patients followed their usual carbohydrate-rich diet for up to 4 weeks. In a second visit (V2), patients chose to either perform a 3-day water fast (WF) or a 14-day ketogenic diet (KD) until a third study visit (V3), after which they returned to their normal high-carbohydrate diet for 3–6 weeks until a final visit (V4). At all visits, total kidney volume (TKV) and total liver volume (TLV) were monitored using MRI; anthropometric parameters, body composition and biochemical parameters (i.e. serum creatinine, complete blood cell count, glucose, β-hydroxybutyrate in fingerstick blood and acetone in breath) were measured. Ketone bodies were evaluated at all visits and in between. Feasibility was examined using respective questionnaires. Undesirable effects such as feelings of hunger and discomfort were documented in a study diary.

RESULTS

All participants (KD: n = 5, WF: n = 5; age: 39.8 ± 11.6 years; eGFR: 82 ± 23.5 mL/min; TKV: 2224 ± 1156 mL) were classified as Mayo Class 1C to 1E. Serum creatinine values were not altered by the ketogenic dietary interventions (V2: 1.17 ± 0.33 mg/dL versus V3: 1.20 ± 0.35 mg/dL, P = 0.826), but serum glucose levels decreased significantly (V2: 84 ± 3 mg/dL, V3: 70 ± 13 mg/dL, P = 0.004). BHB blood levels as well as acetone levels in breath increased in both study arms (V1 to V2 average acetone: 2.6 ± 1.18 ppm, V2 to V3: 22.8 ± 11.9 ppm, P &lt; 0.0001; V1 to V2 average BHB: 0.22 ± 0.08 mmol/L, V2 to V3: 1.89 ± 0.92 mmol/L, P &lt; 0.0001). Nine out of 10 patients reached a ketogenic state during the intervention and 90% evaluated ketogenic interventions as being feasible while 80% of patients both reached the metabolic endpoint and rated ketogenic dietary interventions as feasible. TKV changes during KD and WF did not show any significant differences compared to the period on carbohydrate-rich diet (ΔTKV V1 to V2: 0.75 ± 0.54%, ΔTKV V2 to V3: −1.06 ± 1.16%).

CONCLUSION

The RESET-PKD study demonstrates feasibility of short-term ketogenic interventions both regarding reliable attainment of ketosis and patient-reported feasibility of this intervention in everyday life. In this proof of principle study, short-term ketogenic interventions could not show a significant reduction in TKV. However, this endpoint is likely to require long-term exposure to ketogenesis. Future large-scale clinical trials examining such long-term dietary interventions—e.g. the KETO-ADPKD study—will be of great importance to further evaluate long-term feasibility and the therapeutic potential of ketogenic diets in ADPKD.

FC032: Copeptin as a Potential Biomarker in Patients with Autosomal-Dominant Polycystic Kidney Disease (ADPKD)—Update from the AD(H)PKD Study

BACKGROUND

Prediction of disease progression is one of the main challenges in the treatment of Autosomal-Dominant Polycystic Kidney Disease (ADPKD). In addition to already established biomarkers such as total kidney volume (TKV), further biomarkers that are feasible and easy to collect would be important to allow conclusions on prognosis as well as, in the best case, on long-term treatment response. Post-hoc analyses of the TEMPO 3:4 study showed that copeptin could serve as such a biomarker [1, 2]. In this study, we investigated copeptin over a multi-year course in participants of the AD(H)PKD study.

METHOD

Copeptin was measure from serum samples of 486 patients in the AD(H)PKD study at both initial and follow-up presentations. A total of 95 patients were on tolvaptan therapy at least at one of the measurement time points. We examined the measured values with respect to their distribution in different patient groups (e.g. age, Mayo class) and their changes on tolvaptan administration. Baseline eGFR values were developed using historic creatinine measurements up to 8000 days prior and 1500 days after copeptin measurements. For each patient with at least 5 creatinine measurements an eGFR slope was calculated. The models were developed using a robust linear modelling approach. Slopes were extracted to be the parameter associated to date and multiplied by 365 to retrieve an annual eGFR slope. eGFRs predicted for the specific dates at which copeptin has been measured were then calculated and used in subsequent modelling approaches. To develop a model predictive of eGFR, we used a stepwise regression approach, removing insignificant coefficients at each step.

RESULTS

As expected, copeptin was significantly lower in 391 tolvaptan naive patients than in 95 patients on therapy (9.95 pmol/L versus 19.78 pmol/L; P &lt; 0.0001). More advanced CKD stages showed higher copeptin levels, both with and without tolvaptan, than at lower stages. Independent from kidney function, copeptin levels were consistently higher on tolvaptan than without therapy. Also, larger TKV showed higher copeptin levels in both groups. In 40 patients, copeptin measurements before the start of tolvaptan therapy and follow-up measurements under tolvaptan at the target dose (90/30 mg) were available, and a significant increase in copeptin levels on tolvaptan (copeptin before tolvaptan therapy: 9.798 pmol/L, copeptin on tolvaptan 23.83 pmol/L; P &lt; 0.0001) could be traced during the course. Linear regression models showed that copeptin is an independent variable for the prediction of eGFR slope when added to age, height-adjusted total kidney volume (htTKV) and baseline eGFR. Besides, correlation of predicted future eGFR based on Mayo Classification is slightly but significantly improved by adding copeptin to the model (R2 Mayo 0.9244 and R2 Mayo + copeptin 0.9446).

CONCLUSION

Our data obtained from the real-life setting should again be reconciled with the results from the TEMPO 3:4 cohort. Our findings show that copeptin levels are both associated with kidney function and with future eGFR loss. Adding copeptin to the model of the Mayo Classification indeed improves the prediction of future eGFR. However, it is not clear yet whether this mild effect will have an impact in routine clinical care. Copeptin has the potential to facilitate prognostic assessment as a biomarker and thus could be helpful in deciding on therapy initiation and possibly more patient-specific dosing.

Future analyses of outcome in relation to copeptin will provide further data and might enable implementation in clinical practice.

Immune Responses to SARS-CoV-2 Infection and Vaccination in Dialysis Patients and Kidney Transplant Recipients

Dialysis patients and kidney transplant (KTX) recipients suffer from an impaired immune system and show a decreased response to the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) vaccination. We performed a retrospective analysis of 1505 serological SARS-CoV-2 measurements obtained from 887 dialysis patients and 86 KTX recipients. The results were separated by patient subgroups (dialysis/KTX) as well as SARS-CoV-2 status. The latter criterion included SARS-CoV-2-naïve patients with or without COVID-19 vaccination and convalescent patients receiving a booster shot. Serologies of 27 vaccinated healthy individuals served as the reference group. Vaccine-induced cellular immune response was quantified by an interferon-γ release assay in 32 KTX recipients. We determined seroconversion rates of 92.6%, 93.4%, and 71.4% in dialysis patients vaccinated with either BNT162b2, mRNA-1273, or AZD1222, respectively. Vaccination-induced anti-SARS-CoV-2 antibody titers were lower in dialysis patients compared to healthy individuals, and vaccination with mRNA-1273 induced higher titers than BNT162b2. The initial seroconversion rate was 39.5% in KTX recipients vaccinated with BNT162b2. A linear regression model identified medication with mycophenolate-mofetil/mycophenolic acid as an independent risk factor for missing seroconversion. Within a cohort of 32 KTX recipients, cellular and humoral immune reactivity to SARS-CoV-2 was detectable in three patients only. Conclusively, vaccine-induced seroconversion rates were similar in dialysis patients compared to healthy individuals but were strongly impaired in KTX recipients. Anti-SARS-CoV-2 IgG titers elicited by double active immunization were significantly lower in both cohorts compared to healthy individuals, and immune responses to vaccination vanished quickly.

Ketogenic dietary interventions in autosomal dominant polycystic kidney disease-a retrospective case series study: first insights into feasibility, safety and effects

Background

Our laboratory published the first evidence that nutritional ketosis, induced by a ketogenic diet (KD) or time-restricted diet (TRD), ameliorates disease progression in polycystic kidney disease (PKD) animal models. We reasoned that, due to their frequent use for numerous health benefits, some autosomal dominant PKD (ADPKD) patients may already have had experience with ketogenic dietary interventions (KDIs). This retrospective case series study is designed to collect the first real-life observations of ADPKD patients about safety, feasibility and possible benefits of KDIs in ADPKD as part of a translational project pipeline.

Methods

Patients with ADPKD who had already used KDIs were recruited to retrospectively collect observational and medical data about beneficial or adverse effects and the feasibility and safety of KDIs in questionnaire-based interviews.

Results

A total of 131 ADPKD patients took part in this study. About 74 executed a KD and 52 a TRD for 6 months on average. A total of 86% of participants reported that KDIs had improved their overall health, 67% described improvements in ADPKD-associated health issues, 90% observed significant weight loss, 64% of participants with hypertension reported improvements in blood pressure, 66% noticed adverse effects that are frequently observed with KDIs, 22 participants reported safety concerns like hyperlipidemia, 45 participants reported slight improvements in estimated glomerular filtration rate and 92% experienced KDIs as feasible while 53% reported breaks during their diet.

Conclusions

Our preliminary data indicate that KDIs may be safe, feasible and potentially beneficial for ADPKD patients, highlighting that prospective clinical trials are warranted to confirm these results in a controlled setting and elucidate the impact of KDIs specifically on kidney function and cyst progression.

Combined Therapy with Intravenous Immunoglobulins, Letermovir and (Val-)Ganciclovir in Complicated Courses of CMV-Infection in Transplant Recipients

The treatment options for cytomegalovirus (CMV) infections in immunosuppressed patients are limited, mainly consisting of (val-)ganciclovir (VGC/GCV) as the first-line treatment. We report on three transplant recipients, one stem cell transplant (allo-HSCT) patient and two kidney transplant (KTx) recipients, with prolonged CMV viremia treated with a combined therapy based on letermovir (LMV), CMV-specific intravenous immunoglobulins (IVIg), and VGC/GCV, which led to the sustained control of CMV viremia in all patients.

Modulation of Endocannabinoids by Caloric Restriction Is Conserved in Mice but Is Not Required for Protection from Acute Kidney Injury

Acute kidney injury (AKI) is a frequent and critical complication in the clinical setting. In rodents, AKI can be effectively prevented through caloric restriction (CR), which has also been shown to increase lifespan in many species. In Caenorhabditis elegans (C. elegans), longevity studies revealed that a marked CR-induced reduction of endocannabinoids may be a key mechanism. Thus, we hypothesized that regulation of endocannabinoids, particularly arachidonoyl ethanolamide (AEA), might also play a role in CR-mediated protection from renal ischemia-reperfusion injury (IRI) in mammals including humans. In male C57Bl6J mice, CR significantly reduced renal IRI and led to a significant decrease of AEA. Supplementation of AEA to near-normal serum concentrations by repetitive intraperitoneal administration in CR mice, however, did not abrogate the protective effect of CR. We also analyzed serum samples taken before and after CR from patients of three different pilot trials of dietary interventions. In contrast to mice and C. elegans, we detected an increase of AEA. We conclude that endocannabinoid levels in mice are modulated by CR, but CR-mediated renal protection does not depend on this effect. Moreover, our results indicate that modulation of endocannabinoids by CR in humans may differ fundamentally from the effects in animal models.

Monitoring of hepatitis E virus RNA during treatment for chronic hepatitis E virus infection after renal transplantation

Background

Recently, chronic hepatitis E virus (HEV) infections gained increasing attention as a possible cause for elevated liver enzymes of unknown origin and liver cirrhosis in solid organ transplant recipients. Reduction of immunosuppressive therapy and/or use of antiviral drug ribavirin have been established as possible treatment strategies.

Methods

The efficacy of dose reduction of mycophenolic acid (MPA) and ribavirin therapy was retrospectively analyzed in eight renal transplant patients of our outpatient clinic who were diagnosed with HEV infection by detection of specific antibodies (immunoglobulin M and immunoglobulin G) and/or positive RNA in blood and stool. In four patients serial HEV viral loads in blood were measured.

Results

Only one patient reached HEV clearance after reduction of immunosuppressive therapy (predominantly reduction of MPA daily dose) alone, whereas six patients were treated with ribavirin after reduction of immunosuppressive therapy due to persistent virus replication. Four of six patients reached HEV clearance after 3 months of ribavirin therapy. HEV clearance was observed after 34–42 days. Two patients, both treated with rituximab within the last 12 months before diagnosis of HEV infection, needed prolonged ribavirin therapy due to persistent viral replication.

Conclusion

Reduction of daily dose of MPA therapy alone in transplant patients with chronic HEV infection may not be sufficient to control viral replication. HEV clearance under ribavirin therapy shows interindividual variability. Therefore, serial viral monitoring may be useful to personalize treatment duration. Rituximab therapy is a risk factor for complicated‐to‐treat chronic HEV infection.

Impairment of Neurocognitive Functioning, Motor Performance, and Mood Stability in Hospitalized Patients With Euvolemic Moderate and Profound Hyponatremia

BACKGROUND

The impact of chronic moderate and profound hyponatremia on neurocognitive performance, motor skills, and mood stability has not been investigated systematically so far, and results regarding mild to moderate hyponatremia are inconsistent. Furthermore, it is not known whether treatment has an effect on outcome in these patients.

METHODS

A total of 130 hospitalized patients with confirmed euvolemic hyponatremia (<130 mEq/L) were subjected to a test battery (Mini-Mental State Examination, DemTect, Trail-Making Tests A and B, Beck Depression Inventory, Timed-up-and-go Test) before and after treatment; additionally, 50 normonatremic group-matched patients served as reference group.

RESULTS

The scores of all tested domains were significantly worse in the hyponatremia group (median serum sodium [Na⁺] 122 (119-126) mEq/L) as compared to the reference group (P <0.001), and the odds of obtaining a pathological test result increased markedly with more profound hyponatremic states (odds ratios between 5.0 and 21.8 in the group with Na⁺ <120 mEq/L compared to reference group). Inversely, treatment led to a significant amelioration of all test results with medium to large effect sizes. Linear regression models revealed the increment of Na⁺ as an important predictor of test outcome.

CONCLUSION

We demonstrate a clear association between lower levels of Na⁺ beyond mild hyponatremia and impairment of neurocognitive and motor performance as well as mood disorders. Our analysis further suggests a causal role of hyponatremia in this context. However, there are apparent differences between the distinct tested domains warranting further investigations.

Preconditioning strategies to prevent acute kidney injury

Acute kidney injury is a common clinical disorder resulting in significantly increased morbidity and mortality. However, despite extensive research, strategies for prevention or treatment are still lacking in routine clinical practice. Already decades ago, several preconditioning strategies (e. g. ischemic/hypoxic preconditioning and calorie restriction) have been published and their extraordinary effectiveness - especially in rodents - has raised the hope for powerful clinical tools to prevent acute kidney injury. However, the underlying mechanisms are still not completely understood and translation to the clinics has not been successful yet. In this review, the most attractive strategies and the current mechanistic concepts are introduced and discussed. Furthermore, we present clinical trials evaluating the feasibility of preconditioning in the clinical setting.

Dietary restriction for prevention of contrast-induced acute kidney injury in patients undergoing percutaneous coronary angiography: a randomized controlled trial

Short-term dietary restriction (DR) may prevent organ damage from ischemic or toxic insults in animals, but clear evidence in humans is missing. While especially intraarterial administration of contrast media represents a cause of hospital-acquired acute kidney injury (AKI), targeted preventive strategies are not available. This trial investigated the feasibility and effectiveness of pre-interventional DR for preventing AKI in patients undergoing percutaneous coronary intervention (PCI). Patients were randomized to receive a formula diet containing 60% of daily energy requirement (DR group) or ad-libitum food during the 4-day-interval before PCI. Primary endpoint was change of serum creatinine 48 h after PCI (Δcreatinine). Further analyses included incidence of AKI and safety evaluation. Δcreatinine post PCI in the DR group vs. the control group did not show any difference (DR: 0.03(-0.15,0.14)mg/dL vs. control: 0.09(-0.03,0.22)mg/dL;p = 0.797). Subgroup analyses revealed a significant beneficial impact of DR in patients that received ≤100 ml of contrast agent (DR n = 26: Δcreatinine -0.03(-0.20,0.08)mg/dL vs. control n = 24: Δcreatinine 0.10(-0.08,0.24)mg/dL; p = 0.041) and in patients with ≤2 risk factors for AKI (DR: n = 27; Δcreatinine -0.01(-0.18,0.07)mg/dL vs. control n = 31: Δcreatinine 0.09(-0.03,0.16)mg/dl; p = 0.030). Although the primary endpoint was not met, the results of this trial suggest a beneficial impact of DR in low-to-moderate risk patients.

[Acquired thrombotic-thrombocytopenic purpura - patient management with the advent of novel therapeutic agents]

HISTORY

A 42-year-old female patient presented with pyelonephritis. Two days later she complained of hematomas and petechia of the extremities.

DIAGNOSIS/CLINICAL FINDINGS

Acquired thrombotic thrombocytopenic purpura was diagnosed. Laboratory result showed a thrombotic microangiopathy and thrombocytopenia of 8 × 10E9/l. ADAMTS13-activity was reported to be reduced and inhibitory antibodies to be present.

THERAPY AND COURSE

The patient was placed on a therapy with plasma exchange, high-dose steroids, and caplacizumab based on a positive PLASMIC score. Once the diagnosis was confirmed by diminished ADAMTS13-activity and the presence of autoantibodies, rituximab was added. The patient responded well but showed persistently elevated levels of ADAMTS13-autoantibodies, which lead to an extension of Caplacizumab treatment to 58 days.

DISCUSSION

Caplacizumab represents a novel effective treatment option for patients with acquired thrombocytopenic purpura. Time to treatment response as well as the risk of relapse were shown to be significantly reduced. However, persistent autoimmune activity can be demonstrated in a significant portion of the patients after the end of treatment putting them at risk for relapses. Thus, careful and frequent surveillance is required.

A case report of recurrent membranoproliferative glomerulonephritis after kidney transplantation due to ventriculoatrial shunt infection

Background

Transplant failure requires the consideration of numerous potential causes including rejection, acute tubular necrosis, infection, and recurrence of the original kidney disease. Kidney biopsy is generally required to approach these differential diagnoses. However, the histopathological findings on their own do not always lead to a definite diagnosis. Consequently, it is crucial to integrate them with clinical findings and patient history when discussing histopathological patterns of injury. The histopathologic finding of a membranoproliferative glomerulonephritis (MPGN) is one of the most challenging constellations since it does not refer to a specific disease entity but rather reflects a pattern of injury that is the result of many different causes. Whilst MPGN is occasionally classified as immune complex mediated, careful evaluation usually reveals an underlying disorder such as chronic infection, plasma cell dyscrasia, complement disorders, and autoimmune disease.

Case presentation

We describe the case of a 43-year-old woman who was referred to us because of a slowly rising serum creatinine 4 years after kidney transplantation. As in the native kidney, the biopsy revealed an MPGN pattern of injury. The cause of this finding had not been established prior to transplantation leading to a classification as idiopathic MPGN in the past. Further workup at the time of presentation and allograft failure revealed chronic infection of a ventriculoatrial shunt as the most probable cause.

Conclusion

This case underlines the fact that MPGN is not a disease but a histopathological description. Consequently, the causative disorder needs to be identified to avoid kidney failure and recurrence after transplantation.

Psychological processing of a kidney transplantation, perceived quality of life, and immunosuppressant medication adherence

Introduction: Though psychosocial well-being and quality of life generally improve after transplantation, a relevant proportion of patients suffers from psychosocial problems. Further analysis of the psychological coping after kidney transplantation is needed to identify patients at risk. The aim of this study was to examine the psychological response after kidney transplantation and its associations with health-related quality of life and immunosuppressant medication adherence. Materials and methods: The coping process after kidney transplantation was investigated with the Transplant Effects Questionnaire (TxEQ; subscales: worry, guilt, disclosure, adherence, responsibility) in 267 adult kidney transplant recipients ≥12 months post-transplantation. Furthermore, perceived health-related quality of life, self-reported immunosuppressant medication adherence, and sub-therapeutic immunosuppressant trough levels as biological markers of adherence were assessed. Results: Patients showed moderate scores concerning the subscales "worry", "guilt", and "responsibility" as well as high scores concerning "disclosure". Except for "adherence", all TxEQ subscales were associated with mental, but not with physical health-related quality of life and self-reported adherence. Sub-therapeutic immunosuppressant trough levels were significantly associated only with the TxEQ subscale "worry". Conclusions: The present results suggest a conditional structure in which mental health-related quality of life is negatively associated with worries, guilt, and responsibility and positively with disclosure. Adherence seems to be a complex behavior, which is not necessarily directly associated with the psychological processing of organ transplantations. As mental health-related quality of life is related to this psychological processing, the TxEQ could be used as a screening tool for problematic psychological processing after kidney transplantation.

The proteome microenvironment determines the protective effect of preconditioning in cisplatin-induced acute kidney injury

Acute kidney injury (AKI) leads to significant morbidity and mortality; unfortunately, strategies to prevent or treat AKI are lacking. In recent years, several preconditioning protocols have been shown to be effective in inducing organ protection in rodent models. Here, we characterized two of these interventions-caloric restriction and hypoxic preconditioning-in a mouse model of cisplatin-induced AKI and investigated the underlying mechanisms by acquisition of multi-layered omic data (transcriptome, proteome, N-degradome) and functional parameters in the same animals. Both preconditioning protocols markedly ameliorated cisplatin-induced loss of kidney function, and caloric restriction also induced lipid synthesis. Bioinformatic analysis revealed mRNA-independent proteome alterations affecting the extracellular space, mitochondria, and transporters. Interestingly, our analyses revealed a strong dissociation of protein and RNA expression after cisplatin treatment that showed a strong correlation with the degree of damage. N-degradomic analysis revealed that most posttranscriptional changes were determined by arginine-specific proteolytic processing. This included a characteristic cisplatin-activated complement signature that was prevented by preconditioning. Amyloid and acute-phase proteins within the cortical parenchyma showed a similar response. Extensive analysis of disease-associated molecular patterns suggested that transcription-independent deposition of amyloid P-component serum protein may be a key component in the microenvironmental contribution to kidney damage. This proof-of-principle study provides new insights into the pathogenesis of cisplatin-induced AKI and the molecular mechanisms underlying organ protection by correlating phenotypic and multi-layered omics data.

Mobile Technology Affinity in Renal Transplant Recipients

BACKGROUND

Medication nonadherence is a common problem in renal transplant recipients (RTRs). Mobile health approaches to improve medication adherence are a current trend, and several medication adherence apps are available. However, it is unknown whether RTRs use these technologies and to what extent. In the present study, the mobile technology affinity of RTRs was analyzed. We hypothesized significant age differences in mobile technology affinity and that mobile technology affinity is associated with better cognitive functioning as well as higher educational level.

METHODS

A total of 109 RTRs (63% male) participated in the cross-sectional study, with an overall mean age of 51.8 ± 14.2 years. The study included the Technology Experience Questionnaire (TEQ) for the assessment of mobile technology affinity, a cognitive test battery, and sociodemographic data.

RESULTS

Overall, 57.4% of the patients used a smartphone or tablet and almost 45% used apps. The TEQ sum score was 20.9 in a possible range from 6 (no affinity to technology) to 30 (very high affinity). Younger patients had significantly higher scores in mobile technology affinity. The only significant gender difference was found in having fun with using electronic devices: Men enjoyed technology more than women did. Mobile technology affinity was positively associated with cognitive functioning and educational level.

CONCLUSIONS

Young adult patients might profit most from mobile health approaches. Furthermore, high educational level and normal cognitive functioning promote mobile technology affinity. This should be kept in mind when designing mobile technology health (mHealth) interventions for RTRs. For beneficial mHealth interventions, further research on potential barriers and desired technologic features is necessary to adapt apps to patients' needs.

Preoperative Short-Term Calorie Restriction for Prevention of Acute Kidney Injury After Cardiac Surgery: A Randomized, Controlled, Open-Label, Pilot Trial

BACKGROUND

Acute kidney injury is a frequent complication after cardiac surgery and is associated with adverse outcomes. Although short-term calorie restriction (CR) has proven protective in rodent models of acute kidney injury, similar effects have not yet been demonstrated in humans.

METHODS AND RESULTS

CR_KCH (Effect of a Preoperative Calorie Restriction on Renal Function After Cardiac Surgery) is a randomized controlled trial in patients scheduled for cardiac surgery. Patients were randomly assigned to receive either a formula diet containing 60% of the daily energy requirement (CR group) or ad libitum food (control group) for 7 days before surgery. In total, 82 patients were enrolled between April 16, 2012, and February 5, 2015. There was no between-group difference in the primary end point of median serum creatinine increment after 24 hours (control group: 0.0 mg/dL [-0.1 - (+0.2) mg/dL]; CR group: 0.0 mg/dL [-0.2 - (+0.2) mg/dL]; P=0.39). CR prevented a rise in median creatinine at 48 hours (control group: +0.1 mg/dL [0.0 - 0.3 mg/dL]; CR group: -0.1 mg/dL [-0.2 - (+0.1) mg/dL]; P=0.03), with most pronounced effects observed in male patients and patients with a body mass index >25. This benefit persisted until discharge: Median creatinine decreased by 0.1 mg/dL (-0.2 - 0.0 mg/dL) in the CR group, whereas it increased by 0.1 mg/dL (0.0 - 0.3 mg/dL; P=0.0006) in the control group. Incidence of acute kidney injury was reduced by 5.8% (41.7% in the CR group compared with 47.5% in the control group). Safety-related events did not differ between groups.

CONCLUSIONS

Despite disappointing results with respect to creatinine rise within the first 24 hours, the benefits observed at later time points and the subgroup analyses suggest the protective potential of short-term CR in patients at risk for acute kidney injury, warranting further investigation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01534364.

Psychosocial Variables Associated with Immunosuppressive Medication Non-Adherence after Renal Transplantation

INTRODUCTION

Non-adherence to immunosuppressive medication is regarded as an important factor for graft rejection and loss after successful renal transplantation. Yet, results on prevalence and relationship with psychosocial parameters are heterogeneous. The main aim of this study was to investigate the association of immunosuppressive medication non-adherence and psychosocial factors.

METHODS

In 330 adult renal transplant recipients (≥12 months posttransplantation), health-related quality of life, depression, anxiety, social support, and subjective medication experiences were assessed, and their associations with patient-reported non-adherence was evaluated.

RESULTS

33.6% of the patients admitted to be partially non-adherent. Non-adherence was associated with younger age, poorer social support, lower mental, but higher physical health-related quality of life. There was no association with depression and anxiety. However, high proportions of clinically relevant depression and anxiety symptoms were apparent in both adherent and non-adherent patients.

CONCLUSION

In the posttransplant follow-up, kidney recipients with lower perceived social support, lower mental and higher physical health-related quality of life, and younger age can be regarded as a risk group for immunosuppressive medication non-adherence. In follow-up contacts with kidney transplant patients, physicians may pay attention to these factors. Furthermore, psychosocial interventions to optimize immunosuppressive medication adherence can be designed on the basis of this information, especially including subjectively perceived physical health-related quality of life and fostering social support seems to be of importance.

Up to a Third of Renal Transplant Recipients Have Deficiencies in Cognitive Functioning

INTRODUCTION

Kidney transplantation is beneficial in improving cognitive abilities in patients with chronic kidney disease; however, there is still uncertainty concerning which cognitive domains benefit and to what extent.

AIM

In the present study, cognitive functioning of renal transplant recipients was compared to normative data. Sociodemographic and clinical parameters that were associated with low cognitive performance were identified.

DESIGN

A total of 109 renal transplant recipients (63% men) participated in the study, with a mean age of 51.8 (standard deviation [SD] = 14.2) years. The cognitive test battery consisted of measurements assessing memory, attention, executive function, reproductive, and deductive ability.

RESULTS

In all tests, participants showed mean scores ranging within 1 SD of the population means. However, except for tests measuring memory, the percentage of participants scoring more than 1 SD below normed means was higher than expected in a normal distribution of performance. In certain tests, up to a third of the participants scored below average. Participants with continuous low performance (11%) showed higher age, poorer education, a longer time since transplantation, higher serum levels of urea and creatinine, and were more likely to have a deceased donor allograft.

DISCUSSION

Altough cognitive performance in renal transplant recipients matches normative data and confirms former findings, the amount of patients scoring more than 1 SD below average suggests that there are a considerable number of patients whose cognitive performance in certain domains lies below those of the general population. The identified sociodemographic and biochemical factors might be helpful to identify renal transplant recipients at risk.

Thiazide-Associated Hyponatremia, Report of the Hyponatremia Registry: An Observational Multicenter International Study

BACKGROUND

Hyponatremia is a frequent and potentially life-threatening adverse side effect of thiazide diuretics. This sub-analysis of the Hyponatremia Registry database focuses on current management practices of thiazide-associated hyponatremia (TAH) and compares differences between TAH and syndrome of inappropriate antidiuretic hormone secretion (SIADH).

METHODS

We analyzed 477 patients from 225 US and EU sites with euvolemic hyponatremia ([Na+] ≤130 mEq/L) who were receiving a thiazide diuretic. Of these, 118 met criteria for true thiazide-induced hyponatremia (TIH).

RESULTS

Thiazide was withdrawn immediately after hyponatremia was diagnosed only in 57% of TAH; in these patients, the median rate of [Na+] change (Δdaily[Na+]) was significantly higher than those with continued thiazide treatment (3.8 [interquartile range: 4.0] vs. 1.7 [3.8] mEq/L/day). The most frequently employed therapies were isotonic saline (29.6%), fluid restriction (19.9%), the combination of these two (8.2%), and hypertonic saline (5.2%). Hypertonic saline produced the greatest Δdaily[Na+] (8.0[6.4] mEq/L/day) followed by a combination of fluid restriction and normal saline (4.5 [3.8] mEq/L/day) and normal saline alone (3.6 [3.5] mEq/L/day). Fluid restriction was markedly less effective (2.7 [2.7] mEq/L/day). Overly rapid correction of hyponatremia occurred in 3.1% overall, but in up to 21.4% given hypertonic saline. Although there are highly significant differences in the biochemical profiles between TIH and SIADH, no predictive diagnostic test could be derived.

CONCLUSIONS

Despite its high incidence and potential risks, the management of TAH is often poor. Immediate withdrawal of the thiazide is crucial for treatment success. Hypertonic saline is most effective in correcting hyponatremia but associated with a high rate of overly rapid correction. We could not establish a diagnostic laboratory-based test to differentiate TIH from SIADH.

Randomized Trial of C5a Receptor Inhibitor Avacopan in ANCA-Associated Vasculitis

Alternative C activation is involved in the pathogenesis of ANCA-associated vasculitis. However, glucocorticoids used as treatment contribute to the morbidity and mortality of vasculitis. We determined whether avacopan (CCX168), an orally administered, selective C5a receptor inhibitor, could replace oral glucocorticoids without compromising efficacy. In this randomized, placebo-controlled trial, adults with newly diagnosed or relapsing vasculitis received placebo plus prednisone starting at 60 mg daily (control group), avacopan (30 mg, twice daily) plus reduced-dose prednisone (20 mg daily), or avacopan (30 mg, twice daily) without prednisone. All patients received cyclophosphamide or rituximab. The primary efficacy measure was the proportion of patients achieving a ≥50% reduction in Birmingham Vasculitis Activity Score by week 12 and no worsening in any body system. We enrolled 67 patients, 23 in the control and 22 in each of the avacopan groups. Clinical response at week 12 was achieved in 14 of 20 (70.0%) control patients, 19 of 22 (86.4%) patients in the avacopan plus reduced-dose prednisone group (difference from control 16.4%; two-sided 90% confidence limit, -4.3% to 37.1%; P=0.002 for noninferiority), and 17 of 21 (81.0%) patients in the avacopan without prednisone group (difference from control 11.0%; two-sided 90% confidence limit, -11.0% to 32.9%; P=0.01 for noninferiority). Adverse events occurred in 21 of 23 (91%) control patients, 19 of 22 (86%) patients in the avacopan plus reduced-dose prednisone group, and 21 of 22 (96%) patients in the avacopan without prednisone group. In conclusion, C5a receptor inhibition with avacopan was effective in replacing high-dose glucocorticoids in treating vasculitis.

Patient-reported non-adherence and immunosuppressant trough levels are associated with rejection after renal transplantation

Background

Different measures of non-adherence to immunosuppressant (IS) medication have been found to be associated with rejection episodes after successful transplantation. The aim of the current study was to investigate whether graft rejection after renal transplantation is associated with patient-reported IS medication non-adherence and IS trough level variables (IS trough level variability and percentage of sub-therapeutic IS trough levels).

Methods

Patient-reported non-adherence, IS trough level variability, percentage of sub-therapeutic IS trough levels, and acute biopsy-proven late allograft rejections were assessed in 267 adult renal transplant recipients who were ≥12 months post-transplantation.

Results

The rate of rejection was 13.5%. IS trough level variability, percentage of sub-therapeutic IS trough levels as well as patient-reported non-adherence were all significantly and positively associated with rejection, but not with each other. Logistic regression analyses revealed that only the percentage of sub-therapeutic IS trough levels and age at transplantation remained significantly associated with rejection.

Conclusions

Particularly, the percentage of sub-therapeutic IS trough levels is associated with acute rejections after kidney transplantation whereas IS trough level variability and patient-reported non-adherence seem to be of subordinate importance. Patient-reported non-adherence and IS trough level variables were not correlated; thus, non-adherence should always be measured in a multi-methodological approach. Further research concerning the best combination of non-adherence measures is needed.

Euvolemic hyponatremia in cancer patients. Report of the Hyponatremia Registry: an observational multicenter international study

Purpose

Hyponatremia secondary to SIADH is frequent in cancer patients and potentially deleterious. The aim of this sub-analysis of the Hyponatremia Registry database is to analyze current diagnostic and therapeutic management practices in cancer patients with SIADH.

Methods

We analyzed 358 cancer patients who had serum sodium concentration ([Na⁺]) ≤ 130 mEq/L and a clinical diagnosis of SIADH from 225 sites in the USA and EU.

Results

Precise diagnostic testing was performed in only 46%. Almost 12% of all patients did not receive any hyponatremia treatment. The most frequent therapies were fluid restriction (20%), isotonic saline (14%), fluid restriction/isotonic saline (7%), tolvaptan (8%), and salt tablets (7%). Hypertonic saline was used in less than 3%. Tolvaptan produced the greatest median rate of [Na⁺] change (IQR) (3.0 (4.7) mEq/L/day), followed by hypertonic saline (2.0(7.0) mEq/L/day), and fluid restriction/isotonic saline (1.9(3.2) mEq/L/day). Both fluid restriction and isotonic saline monotherapies were significantly less effective (0.8(2.0) mEq/L/day and 1.3(3.0) mEq/L/day, respectively) and were associated with clinically relevant rates of treatment failure. Only 46% of patients were discharged with [Na⁺] ≥ 130 mEq/L. Overly rapid correction of hyponatremia occurred in 11.7%.

Conclusions

Although essential for successful hyponatremia management, appropriate diagnostic testing is not routinely performed in current practice. The most frequently employed monotherapies were often ineffective and sometimes even aggravated hyponatremia. Tolvaptan was used less often but showed significantly greater effectiveness. Despite clear evidence that hyponatremia is associated with poor outcome in oncology patients, most patients were discharged still hyponatremic. Further studies are needed to assess the beneficial impact of hyponatremia correction with effective therapies.

Electronic supplementary material

The online version of this article (doi:10.1007/s00520-017-3638-3) contains supplementary material, which is available to authorized users.

Monoclonal gammopathy-associated pauci-immune extracapillary-proliferative glomerulonephritis successfully treated with bortezomib

Extracapillary-proliferative glomerulonephritis is a rare complication of multiple myeloma. Partial remission of kidney involvement with cyclophosphamide therapy has previously been described. We report the case of a 60-year-old male patient diagnosed with rapidly progressive glomerulonephritis associated with IgG kappa monoclonal gammopathy. His kidney biopsy revealed pauci-immune extracapillary-proliferative glomerulonephritis without cryoglobulinaemia. Treatment with the proteasome inhibitor bortezomib induced rapid clinical and histological remission of his kidney disease. The patient's renal function remained stable on bortezomib maintenance therapy. Our findings suggest that bortezomib is a promising therapeutic approach to ameliorate severe kidney damage in monoclonal gammopathy- and myeloma-associated pauci-immune extracapillary-proliferative glomerulonephritis.

Survival and distribution of injected haematopoietic stem cells in acute kidney injury

BACKGROUND

Endogenous bone marrow-derived cells are known to incorporate into renal epithelium at a low rate. Haematopoietic stem cells (HSCs) rather than mesenchymal stem cells (MSC) are responsible for this phenomenon. MSCs have the potential to ameliorate kidney function after acute kidney injury (AKI) without directly repopulating the tubules. However, little is known about the short-term effect of HSCs.

METHODS

In this article, we analysed the survival rate and organ distribution of isolated rat HSCs injected into the renal artery after ischaemic renal injury, using quantitative real-time PCR, as well as their impact on renal function and histomorphology.

RESULTS

Intra-arterially injected Lin(-)CD90(+) HSCs were detected in the kidney at significant amounts only within the first 24 h after injection and were virtually absent by Day 2. Compared with control animals, no differences were seen after HSC administration with respect to kidney function or histomorphologic changes of AKI. At Day 7 HSCs were again readily detectable in the kidney suggesting a redistribution of cells at later time points. Of note, HSCs did not seem to have an exclusive tropism for the injured kidney but were detectable in the lungs, liver, spleen, heart and brain at all time points.

CONCLUSIONS

Injected HSCs do not appear to significantly contribute to tubular repair or ameliorate renal damage in ischaemic AKI although they may show considerable engraftment in various organs. These data further challenge the concept that injection of HSCs may be used as a therapeutic approach in treating AKI.

Differential increase of CD34, KDR/CD34, CD133/CD34 and CD117/CD34 positive cells in peripheral blood of patients with acute myocardial infarction

OBJECTIVE

Circulating progenitor cells (CPC) may contribute to cardiac regeneration and neovascularization after acute myocardial infarction (AMI). For potential therapeutic use, understanding the endogenous mechanisms after ischemia is inevitable. We investigated the absolute number, but also the subset composition of CD34+ CPC after AMI.

METHODS

CD34+, KDR+/CD34+, CD133+/CD34+ and CD117+/CD34+CPC were analyzed by FACS in peripheral blood of 10 patients with acute MI (59+/-5 yrs, m/f=8/2) at day of AMI (day 0) and days 1-5. For comparison patients with stable coronary artery disease (CAD, n=12, 66+/-2 yrs, m/f=10/2) and young healthy volunteers (n=7, 26+/-2 yrs, m/f=3/4) were studied.

RESULTS

CD34 and KDR/CD34, CD133/CD34, CD117/CD34 were increased day 3 and 4 after AMI. KDR+ fraction within CD34+ population remained unchanged (58.3+/-7.8% vs 55.3+/-10.6%), whereas CD133+ (64.9+/-3.1% vs 43.5+/-5.9%, P=0.006) and CD117+ fractions (71.7+/-5.6% vs 50.1+/-5.5%, P=0.02) were elevated. In CAD, all CPC and fractions were similar as AMI day 0. Healthy volunteers had more CD34+ than CAD and AMI day 0. Double positive CPC were also higher, but fractions were unchanged vs CAD with more KDR/CD34 in trend (72.8+/-10.6% vs 50.5+/-5.6%, P=0.058). After AMI both absolute numbers of CD34+ and their subset composition change, suggesting selective mobilization of CPC. Increased CPC after AMI never reach numbers of young healthy volunteers.

The mobilization of CD34 positive mononuclear cells after myocardial infarction is abolished by revascularization of the culprit vessel

BACKGROUND

The mobilization of hematopoietic progenitor cells from bone marrow has been proposed to play a role in cardiac regeneration after myocardial infarction (MI). Accordingly, an increase in CD34 positive cells (CD34+) has been observed in the peripheral blood of patients after acute myocardial infarction. Here, we evaluated the influence of an acute percutaneous coronary intervention (PCI) of the occluded artery on the mobilization of CD34+ in acute MI.

METHODS

CD34 positive cells were quantified by flow cytometry (FACS analysis) and expressed as number per million white blood cells. Peripheral blood was obtained and analyzed at day 5 after the onset of symptoms from patients with acute MI without early PCI (n=11, age 63+/-5 years), acute MI with rapid PCI (n=7, age 63+/-3), patients with pneumonia (n=5, age 51+/-6), patients without angiographical signs of coronary artery disease (control, n=5, age 66+/-8) and young healthy volunteers (n=11, age 28+/-1).

RESULTS

Patients with MI but without PCI had a higher CD34+ count at day 5 (312+/-48 per 10(6) leukocytes) than control (156+/-40, P=0.03) and MI with PCI (173+/-31, P=0.03). No increase in CD34+ was observed in patients who underwent PCI vs. control. Patients with pneumonia had higher CD34+ (350+/-44) than patients with MI with PCI (P=0.01) and control (P=0.01). Healthy individuals who were much younger than all other groups (28+/-1 years, P<0.0001 vs. all groups) had the highest CD34+ (526+/-51, P=0.006 vs. MI without PCI, P=0.00003 vs. MI with PCI, P=0.02 vs. pneumonia, P=0.00006 vs. control).

CONCLUSIONS

Shorter time of ischemia and reduced cell death may be the reasons for reduced CD34+ cell count after acute MI with early percutaneous intervention vs. acute MI without intervention. Besides ischemia, also inflammation as present in pneumonia may cause a mobilization of CD34+ cells. Age may be a major factor that influences the mobilization of CD34+ cells and the regenerative capacity of the heart.