von Willebrand Factor Multimer Formation Contributes to Immunothrombosis in Coronavirus Disease 2019.

OBJECTIVES: Prevention and therapy of immunothrombosis remain crucial challenges in the management of coronavirus disease 2019, since the underlying mechanisms are incompletely understood. We hypothesized that endothelial damage may lead to substantially increased concentrations of von Willebrand factor with subsequent relative deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13). DESIGN: Prospective controlled cross-over trial. SETTING: Blood samples of patients with confirmed coronavirus disease 2019 and healthy controls were obtained in three German hospitals and analyzed in a German hemostaseologic laboratory. PATIENTS: Seventy-five patients with confirmed coronavirus disease 2019 of mild to critical severity and 30 healthy controls. MEASUREMENTS AND MAIN RESULTS: von Willebrand factor antigen, ADAMTS13, and von Willebrand factor multimer formation were analyzed. von Willebrand factor antigen was 4.1 times higher in COVID-19 patients compared with healthy controls (p < 0.0001), whereas ADAMTS13 activities were not significantly different (p = 0.18). The ADAMTS13/von Willebrand factor antigen ratio was significantly lower in COVID-19 than in the control group (24.4 ± 20.5 vs 82.0 ± 30.7; p < 0.0001). Fourteen patients (18.7%) undercut a critical ratio of 10 as described in thrombotic thrombocytopenic purpura. Gel analysis of multimers resembled a thrombotic thrombocytopenic purpura pattern with loss of the largest multimers in 75% and a smeary triplet pattern in 39% of the patients. The ADAMTS13/von Willebrand factor antigen ratio decreased continuously from mild to critical disease (analysis of variance p = 0.026). Furthermore, it differed significantly between surviving patients and those who died from COVID-19 (p = 0.001) yielding an area under the curve of 0.232 in receiver operating characteristic curve curve analysis. CONCLUSION: COVID-19 is associated with a substantial increase in von Willebrand factor levels, which can exceed the ADAMTS13 processing capacity resulting in the formation of large von Willebrand factor multimers indistinguishable from thrombotic thrombocytopenic purpura. The ADAMTS13/von Willebrand factor antigen ratio is an independent predictor of severity of disease and mortality. These findings provide a rationale to consider plasma exchange as a therapeutic option in COVID-19 and to include von Willebrand factor and ADAMTS13 in the diagnostic workup.

Urinary calprotectin, NGAL, and KIM-1 in the differentiation of primarily inflammatory vs. non-inflammatory stable chronic kidney diseases.

INTRODUCTION: It has been demonstrated that urinary neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin are helpful biomarkers in the differentiation of intrinsic and prerenal acute kidney injury. OBJECTIVE: The present cross-sectional study investigates, whether urinary biomarkers are able to differentiate primarily inflammatory from non-inflammatory entities in chronic kidney disease (CKD). METHODS: Urinary calprotectin, NGAL, and kidney injury molecule-1 (KIM-1) concentrations were assessed in a study population of 143 patients with stable CKD and 29 healthy controls. Stable renal function was defined as an eGFR fluctuation ≤5 ml/min/1.73 m2 in the past 12 months. Pyuria, metastatic carcinoma, and renal transplantation were regarded as exclusion criteria. Diabetic nephropathy, hypertensive nephropathy, and polycystic kidney disease were categorized as 'primarily non-inflammatory renal diseases' (NIRD), whereas glomerulonephritis and vasculitis were regarded as 'primarily inflammatory renal diseases' (IRD). RESULTS: Urinary calprotectin and NGAL concentrations significantly differed between CKD and healthy controls (p < 0.05 each), whereas KIM-1 concentrations did not (p = 0.84). The three biomarkers did neither show significant differences in-between the individual entities, nor the two categories of IRD vs. NIRD (calprotectin 155.7 vs. 96.99 ng/ml; NGAL 14 896 vs. 11 977 pg/ml; KIM-1 1388 vs. 1009 pg/ml; p > 0.05 each). Albumin exceeds the diagnostic power of the investigated biomarkers by far. CONCLUSIONS: The urinary biomarkers calprotectin, NGAL, and KIM-1 have no diagnostic value in the differentiation of primarily inflammatory vs. non-inflammatory etiologies of CKD.

Immune monitoring facilitates the clinical decision in multifocal COVID-19 of a pancreas-kidney transplant patient.

The optimal management in transplant recipients with coronavirus disease 2019 (COVID-19) remains uncertain. The main concern is the ability of immunosuppressed patients to generate sufficient immunity for antiviral protection. Here, we report on immune monitoring facilitating a successful outcome of severe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated pneumonia, meningoencephalitis, gastroenteritis, and acute kidney and pancreas graft failure in a pancreas-kidney transplant recipient. Despite the very low numbers of circulating B, NK, and T cells identified in follow-up, a strong SARS-CoV-2 reactive T cell response was observed. Importantly, we detected T cells reactive to Spike, Membrane, and Nucleocapsid proteins of SARS-CoV-2 with majority of T cells showing polyfunctional proinflammatory Th1 phenotype at all analyzed time points. Antibodies against Spike protein were also detected with increasing titers in follow-up. Neutralization tests confirmed their antiviral protection. A correlation between cellular and humoral immunity was observed underscoring the specificity of demonstrated data. We conclude that analyzing the kinetics of nonspecific and SARS-CoV-2-reactive cellular and humoral immunity can facilitate the clinical decision on immunosuppression adjustment and allow successful outcome as demonstrated in the current clinical case. Although the antiviral protection of the detected SARS-CoV-2-reactive T cells requires further evaluation, our data prove an ability mounting a strong SARS-CoV-2-reactive T cell response with functional capacity in immunosuppressed patients.

Allograft infiltration and meningoencephalitis by SARS-CoV-2 in a pancreas-kidney transplant recipient.

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) preferentially affects epithelia of the upper and lower respiratory tract. Thus, impairment of kidney function has been primarily attributed until now to secondary effects such as cytokine release or fluid balance disturbances. We provide evidence that SARS-CoV-2 can directly infiltrate a kidney allograft. A 69-year-old male, who underwent pancreas-kidney transplantation 13 years previously, presented to our hospital with coronavirus disease 2019 (COVID-19) pneumonia and impaired pancreas and kidney allograft function. Kidney biopsy was performed showing tubular damage and an interstitial mononuclear cell infiltrate. Reverse transcriptase polymerase chain reaction from the biopsy specimen was positive for SARS-CoV-2. In-situ hybridization revealed SARS-CoV-2 RNA in tubular cells and the interstitium. Subsequently, he had 2 convulsive seizures. Magnetic resonance tomography suggested meningoencephalitis, which was confirmed by SARS-CoV-2 RNA transcripts in the cerebrospinal fluid. The patient had COVID-19 pneumonia, meningoencephalitis, and nephritis. SARS-CoV-2 binds to its target cells through angiotensin-converting enzyme 2, which is expressed in a broad variety of tissues including the lung, brain, and kidney. SARS-CoV-2 thereby shares features with other human coronaviruses including SARS-CoV that were identified as pathogens beyond the respiratory tract as well. The present case should provide awareness that extrapulmonary symptoms in COVID-19 may be attributable to viral infiltration of diverse organs.

Association of hyperuricemia and serum uric acid lowering therapy with mortality in hemodialysis patients.

INTRODUCTION: In the general population, hyperuricemia is associated with increased morbidity and mortality. Data on this association in hemodialysis patients is controversial. Moreover, it remains elusive whether serum uric acid (SUA) lowering therapy is associated with mortality. METHODS: Retrospective analysis of 601 patients on chronic hemodialysis therapy in five outpatient centers with a maximum follow-up of 100 and a mean follow-up of 41 months. Death was defined as primary endpoint. Cumulative survival was analyzed by Kaplan-Meier analysis and Cox regressions adjusted for age. FINDINGS: Cumulative survival rates were higher for those subjects with a higher than median SUA concentration both based on mean annual and baseline measurements (p < 0.05 each). There was no survival difference anymore after adjustment for age (p > 0.05 each). Stratification for SUA lowering therapy (allopurinol/febuxostat) had no impact on cumulative survival, neither in Kaplan Meier nor in Cox regression analyses (p > 0.05 each). Furthermore, Cox regression analysis excluded an increased cardiovascular mortality in subjects with hyperuricemia. DISCUSSION: In contrast to the general population, hyperuricemia is not associated with increased mortality in patients undergoing hemodialysis. Moreover, xanthine oxidase inhibition was not associated with a survival benefit in this analysis. These data do not support the use of SUA lowering medication in hemodialysis patients with asymptomatic hyperuricemia.

The impact of blood pressure variability and pulse pressure on graft survival and mortality after kidney transplantation.

BACKGROUND: Blood pressure variability and pulse pressure are strong and independent predictors of cardiovascular morbidity and mortality in the general population. So far, there are no data on the impact of blood pressure variability on mortality and graft survival after renal transplantation. METHODS: We performed a retrospective analysis of 877 patients who underwent kidney transplantation between 1997 and 2011 in two transplant centers in Germany (Berlin and Bochum) with a follow-up of 12-266 months. Visit-to-visit blood pressure variability over the first 12 months after transplantation (3 visits) and during the first 120 months after transplantation (7 visits) was calculated as the coefficient of variation (CV = standard deviation (SD)/mean blood pressure). Patient and graft survival was defined as composite endpoint. RESULTS: Cumulative survival was significantly higher for those patients with lower systolic blood pressure and pulse pressure within both the first 12 months and the 120 months posttransplant. After adjustment of data for gender, age, body mass index, and coronary artery disease, the cumulative incidence of the combined endpoint did not significantly differ between patients with lower vs higher CV (12 months CV hazard ratio (HR) (95% CI) = 0.90 (0.66-1.23), P = 0.51; 120 months CV HR (95% CI) = 0.92 (0.67-1.26), P = 0.60). A lower systolic blood pressure remained highly predictive for better survival in adjusted analyses. CONCLUSION: Visit-to-visit blood pressure variability is not associated with mortality or graft loss after kidney transplantation in this retrospective analysis. In analogy to the general population, however, there is an inverse relationship of survival and pulse pressure as a marker of arterial stiffness.

Urinary Biomarkers in the Prediction of Prognosis and Treatment Response in IgA Nephropathy.

BACKGROUND/AIMS: The addition of immunosuppression to supportive care reduces proteinuria in a subset of patients with IgA nephropathy (IgAN) but is associated with an increased rate of adverse events. The present work investigates whether urinary biomarkers are able to identify subjects who benefit from immunosuppression and to predict the progression of disease in a sub-cohort of the STOP-IgAN trial. METHODS: Urinary neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), calprotectin, and the product of tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 (TIMP2•IGFBP7) were measured in all available urine samples obtained at the time point of enrollment in the STOP-IgAN trial (n=113). RESULTS: Biomarker concentrations in both the overall study population and the subgroup with additional immunosuppression did not differ in subjects reaching vs. not reaching full clinical remission, eGFR loss ≥ 15, or 30 ml/min/1.73 m2 over the 3-year trial phase (p> 0.05 each). Receiver-operating characteristic curves showed a poor predictive accuracy of each biomarker for the above-mentioned parameters in the overall study population (areas under the curve ≤0.611). Accordingly, there was neither a significant correlation of any biomarker and adverse outcome in linear regression analysis, nor between biomarker concentrations at enrollment and change in the eGFR over the 3-year observation period. CONCLUSION: NGAL, KIM-1, calprotectin, and [TIMP-2]•[IGFBP7] had neither a prognostic value for the progression of IgAN, nor for the response to immunosuppression in the present sub-cohort of the STOP-IgAN trial. The search for appropriate biomarkers for an individualized treatment strategy in IgAN continues.

Prognostic Value of Urinary Calprotectin, NGAL and KIM-1 in Chronic Kidney Disease.

BACKGROUND/AIMS: Urinary biomarkers like neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) do not only allow an early diagnosis of acute kidney injury, but also provide prognostic information in this setting. The present prospective study investigates, whether the urinary biomarkers NGAL, KIM-1 and calprotectin have prognostic information in chronic kidney disease (CKD) as well. METHODS: Urinary calprotectin, NGAL and KIM-1 concentrations were assessed in a study population of 143 patients with stable CKD comprising diabetic and hypertensive nephropathy, glomerulonephritis/vasculitis, and autosomal dominant polycystic kidney disease. An eGFR fluctuation > 5ml/min/1.73m2 in the past 12 months was defined as an exclusion criterion in order to exclude cases with acute on chronic kidney injury. Renal function was monitored for a median follow-up of 37 months. RESULTS: In the overall study population, all the three biomarkers failed to predict DeGFR and DACR from baseline to follow-up in linear regression analysis adjusted for age, gender, and baseline eGFR. Contrarily, baseline ACR was significantly associated with DeGFR (p< 0.001). In the subgroup of patients with vasculitis and glomerulonephritis, all the three biomarkers were significantly associated with DeGFR, with calprotectin having the highest regression coefficient. CONCLUSION: In contrast to the traditional biomarker "albuminuria", neither the inflammatory biomarker calprotectin, nor the tubular biomarkers NGAL and KIM-1, provide robust prognostic information on the loss or renal function in a heterogeneous CKD population. All of them, however, are candidate prognostic biomarkers in primarily inflammatory renal diseases.

Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD) MRI.

BACKGROUND/AIMS: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) measures tissue oxygenation based on the transverse relaxation rate (R2*). The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. METHODS: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI), 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS) with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R)-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14). BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. RESULTS: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively). Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each). Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each), whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each). CONCLUSION: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

Urinary calprotectin, kidney injury molecule-1, and neutrophil gelatinase-associated lipocalin for the prediction of adverse outcome in pediatric acute kidney injury.

Early identification of patients with acute kidney injury (AKI) being at high risk for adverse outcome can influence medical treatment. This study compares urinary calprotectin, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) for their performance in predicting mortality and need for renal replacement therapy (RRT) in pediatric AKI patients. Urinary biomarker concentrations were assessed prospectively in 141 subjects aged 0-18 years including 55 patients with established AKI according to pediatric Risk, Injury, Failure, Loss, and End-stage kidney disease (pRIFLE) criteria, 27 patients without AKI, and 59 healthy children. Within the AKI group, receiver operating characteristic (ROC) curve analysis revealed moderate to poor performance of calprotectin and KIM-1 in the prediction of 30-day mortality (calprotectin area under the curve (AUC) 0.55; KIM-1 AUC 0.55) and 3-month mortality (calprotectin AUC 0.61; KIM-1 AUC 0.60) and fair performance in the prediction of RRT requirement (calprotectin AUC 0.72; KIM-1 AUC 0.71). Urinary NGAL showed good performance in predicting 30-day (AUC 0.79) and 3-month (AUC 0.81) mortality and moderate performance in predicting RRT (AUC 0.61). CONCLUSIONS: Whereas urinary calprotectin and KIM-1 can be useful for the prediction of RRT, urinary NGAL has a good diagnostic performance in predicting mortality in pediatric patients with AKI of heterogeneous etiology. What is known: • There is increasing evidence that urinary biomarkers like neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) are valuable for the prediction of adverse outcome in adult acute kidney injury (AKI), whereas data on pediatric AKI is scarce. What is new: • Urinary calprotectin and KIM-1 do not predict mortality in our heterogeneous pediatric AKI cohort, but they show moderate performance in the prediction of dialysis. • Urinary NGAL is a good predictor of mortality performing better than pRIFLE stage, eGFR, or creatinine, but it shows moderate performance in the prediction of dialysis.

Urinary biomarkers for the differentiation of prerenal and intrinsic pediatric acute kidney injury.

BACKGROUND: Urinary calprotectin and neutrophil gelatinase-associated lipocalin (NGAL) have recently been identified as promising biomarkers for the differentiation of prerenal and intrinsic acute kidney injury (AKI) in adults. In the study reported here we examined the diagnostic accuracy of calprotectin, NGAL, and kidney injury molecule 1 (KIM-1) in pediatric patients. METHODS: Urinary calprotectin, NGAL, and KIM-1 concentrations were assessed in a study population of 139 pediatric subjects including 39 patients with intrinsic AKI, 14 with prerenal AKI, and 86 non-AKI subjects. RESULTS: Median urinary calprotectin and NGAL concentrations were higher in patients with intrinsic AKI than in those with prerenal AKI (calprotectin by 22-fold, NGAL by 9-fold). Receiver operating characteristic (ROC) curve analyses for the differentiation of intrinsic and prerenal AKI resulted in an area under the curve (AUC) of 0.90 [95 % confidence interval (CI) 0.81-0.98] for calprotectin and 0.73 (95 % CI 0.58-0.87) for NGAL. Median urinary KIM-1 concentrations were not significantly different between patients with prerenal AKI and those with intrinsic disease (P = 0.98; AUC 0.50, 95 % CI, 0.35-0.65). The AUC for the fractional excretion of sodium (FENa) and proteinuria was 0.78 (95 % CI 0.63-0.92) and 0.77 (CI 0.65-0.90), respectively. CONCLUSIONS: Urinary calprotectin outperforms NGAL, KIM-1, FENa, and proteinuria as a biomarker for the differentiation of prerenal and intrinsic AKI in pediatric patients with a high diagnostic accuracy.

Urinary calprotectin: a new diagnostic marker in urothelial carcinoma of the bladder.

PURPOSE: Recently, a proteomic study of sera from patients with bladder cancer identified S100A8 and S100A9 as tumor-associated proteins. The present cross-sectional study investigates whether calprotectin, the heterodimer of S100A8/S100A9 may serve as a urinary biomarker for the detection of urothelial bladder cancer. METHODS: Urinary calprotectin concentrations were assessed in a population of 181 subjects including 46 cases of bladder cancer. 41 cases of renal cell cancer, 54 cases of prostate cancer, and 40 healthy subjects served as control. Acute kidney injury, urinary tract infection, previous BCG-treatment and secondary transurethral resection of the bladder tumor were defined as exclusion criteria. Assessment was performed by enzyme-linked immunosorbent assay and immunohistochemistry detecting calprotectin. RESULTS: Median calprotectin concentrations (ng/ml) were significantly higher in patients with bladder cancer than in healthy controls (522.3 vs. 51.0, p < 0.001), renal cell cancer (90.4, p < 0.001), and prostate cancer (71.8, p < 0.001). In urothelial carcinoma prominent immunostaining occurred in a subset of tumor cells and in infiltrating myeloid cells. Receiver operating characteristic analysis provided an area under the curve of 0.88 for the differentiation of bladder cancer and healthy control. A cut-off value of 140 ng/ml (determined by Youden's index) resulted in sensitivity and specificity values of 80.4 and 92.5 %. Low grade tumors were associated with significantly lower calprotectin concentrations than high grade tumors (351.9 vs. 1635.2 ng/ml, p = 0.004). CONCLUSIONS: Urothelial malignancies are associated with highly increased concentrations of calprotecin in the urine. In absence of renal failure and pyuria, calprotectin constitutes a promising biomarker for the detection of bladder cancer.

Differential impact of belatacept and cyclosporine A on central aortic blood pressure and arterial stiffness after renal transplantation.

Calcineurin inhibitors (CNI) are potent vasoconstrictors and induce an acceleration of arteriosclerosis, thus contributing to the cardiovascular risk after renal transplantation. The study compares the impact of belatacept and cyclosporine A (CsA) on arterial stiffness and central aortic blood pressure. We performed a case-control study in 46 patients (23 on belatacept and 23 on CsA) matched for age, body mass index, time after transplantation, and time on dialysis prior to transplantation. Pulse wave analysis (SphygmoCor, AtCor(®) ) was used to assess central aortic blood pressure, aortic augmentation pressure, and pulse wave velocity (PWV) as a marker of arterial stiffness. Assessment of vascular function was performed after a minimum of 20 months and a median follow-up of 81 months post-transplant. Peripheral systolic and diastolic blood pressure did not significantly differ in the two groups (p > 0.05 each). The central aortic augmentation pressure was higher in the CsA group (12.7 mmHg vs. 7.3 mmHg, p = 0.048). PWV as a measure of arterial stiffness did not differ in the two groups. Thus, belatacept is not associated with a significant difference in arterial stiffness compared to CsA after a median of 81 months post-transplant. It is associated, however, with a lower aortic augmentation pressure, a strong independent cardiovascular risk factor.

Prevalence of masked hypertension in attended versus unattended office blood pressure measurement.

There is a controversial debate regarding whether unattended blood pressure (BP) measurement should be regarded as the new gold standard of office BP measurement. Unattended BP measurement eliminates the white-coat effect and reduces external influences on the patient. On the other hand, it might underestimate real-life BP. The present study compares the prevalence of masked hypertension using attended versus unattended office BP measurements. We performed a cross-sectional study on 213 patients in a general practitioner's outpatient clinic and compared attended and unattended office BP with 24h-ambulatory BP monitoring (24h-ABPM). Masked hypertension was defined as pressure ≥135/85 mmHg in daytime ABPM with office systolic BP < 140/90 mmHg. Median attended and unattended office BPs were 140/86 and 134/80 mmHg with a median 24h-BP of 129/79 mmHg and daytime ABP of 133/82 mmHg. The number of patients with masked hypertension was 45/213 (21.2%) using unattended and 23/213 (10.8%) using attended office BP measurements (p < .0001). Bland-Altman analysis revealed a 7.4 mmHg systolic and 6.2 mmHg diastolic bias between the attended versus unattended office BP, and two systolic and -1.7 mmHg diastolic biases between the unattended office BP and daytime ambulatory BP. In linear regression analysis, an unattended office BP of 134 mmHg corresponded to 140 mmHg in attended BP measurement. Using a cut-off of 135/85 mmHg instead of 140/90 mmHg in unattended office BP measurement, the rate of masked hypertension was 26/213 (12.2%). Thus, unattended office BP measurement results in a substantial increase in the prevalence of masked hypertension using the traditional definition of hypertension. The present findings suggest that it might be reasonable to use a definition of 135/85 mmHg.

Flexible-meccano: a tool for the generation of explicit ensemble descriptions of intrinsically disordered proteins and their associated experimental observables.

MOTIVATION: Intrinsically disordered proteins (IDPs) represent a significant fraction of the human proteome. The classical structure function paradigm that has successfully underpinned our understanding of molecular biology breaks down when considering proteins that have no stable tertiary structure in their functional form. One convenient approach is to describe the protein in terms of an equilibrium of rapidly inter-converting conformers. Currently, tools to generate such ensemble descriptions are extremely rare, and poorly adapted to the prediction of experimental data. RESULTS: We present flexible-meccano-a highly efficient algorithm that generates ensembles of molecules, on the basis of amino acid-specific conformational potentials and volume exclusion. Conformational sampling depends uniquely on the primary sequence, with the possibility of introducing additional local or long-range conformational propensities at an amino acid-specific resolution. The algorithm can also be used to calculate expected values of experimental parameters measured at atomic or molecular resolution, such as nuclear magnetic resonance (NMR) and small angle scattering, respectively. We envisage that flexible-meccano will be useful for researchers who wish to compare experimental data with those expected from a fully disordered protein, researchers who see experimental evidence of deviation from 'random coil' behaviour in their protein, or researchers who are interested in working with a broad ensemble of conformers representing the flexibility of the IDP of interest. AVAILABILITY: A fully documented multi-platform executable is provided, with examples, at http://www.ibs.fr/science-213/scientific-output/software/flexible-meccano/ CONTACT: martin.blackledge@ibs.fr.

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.

Impact of weather changes on hospital admissions for hypertension.

Blood pressure (BP) shows a seasonal variation with higher levels at lower temperatures. Many hypertensives, however, report on BP disturbances rather in association with acutely changing weather conditions than with absolute temperatures. To date, the impact of changing meteorological parameters on hypertensive episodes remains elusive. We performed a retrospective time series regression analysis on 203,703 patients in three hospitals in Germany between 2010 and 2018, of whom 7362 patients were admitted for hypertensive disease. Numbers of daily admissions for hypertension were associated with metereological data obtained from three nearby weather stations. Data comprised temperature (mean, maximal, minimal and range within 24 h), athmospheric pressure, and precipitation. Changes of these parameters were calculated over a two and three day period. There was an inverse correlation between maximal daily temperature and the number of admissions for hypertensive disease, which remained significant both after adjustment for seasonality and week day in a spline model and in a constrained distributed lag model. A decrease of maximal temperature by 5 °C was associated with a 3% increase of risk for admission for hypertension and vice versa. There were no significant effects of precipitation and athmospheric pressure on the number of admissions. With regard to all observed metereological parameters, neither the change within two, nor within three days was consistently associated with the number of daily admissions. High temperatures are associated with lower numbers of hypertensive episodes requiring hospital admission. In contrast to the subjective perception of many hypertensive patients, however, acutely changing weather conditions are not associated with a higher risk of hypertensive emergency.

Estimation of LDL cholesterol in chronic kidney disease.

AIMS: Most of the laboratories make use of the Friedewald formula to assess low-density lipoprotein cholesterol (LDL-C). The accuracy of this approach, however, crucially depends on triglyceride concentrations. Since hypertriglyceridaemia is a characteristic trait of the lipid profile in chronic kidney disease (CKD), the present study examines the accuracy of the Friedewald formula in this population. It aims to derive and validate a more accurate equation for CKD. METHODS: Cross-sectional study on two cohorts of subjects (overall n = 3.514) with estimated glomerular filtration rate (eGFR) <60 mL/min comparing directly measured LDL-C (LDL-Cmeas) as assessed by an enzymatic assay (Roche, Switzerland) to concentrations estimated by the Friedewald (LDL-CF) and the Martin's formula (LDL-CM). Accuracy was analysed by Bland-Altman and linear regression analyses. In the first cohort, a novel formula was derived to assess LDL-C in CKD. The formula was validated in Cohort 2. RESULTS: Cohort 1 comprised 1738 subjects, and Cohort 2 comprised 1776 subjects. The mean eGFR was 29.4 ± 14.4 mL/min. In Cohort 1, LDL-CF was highly correlated with LDL-Cmeas (R2 = 0.92) but significantly underestimated LDLmeas by 11 mg/dL. LDL-C = cholesterol - HDL - triglycerides/7.98 was derived as the optimal equation for the calculation of LDL-C in Cohort 1 and was successfully validated in Cohort 2 (bias of 1.6 mg/dL). The novel formula had a higher accuracy than both the Friedewald (bias -12.2 mg/dL) and the Martin's formula (bias -4.8 mg/dL). CONCLUSION: The Friedewald formula yields lower LDL-C concentrations in CKD than direct enzymatic measurements, which may lead to undersupply of this cardiovascular high-risk population in a treat-to-target approach.

The impact of acute diarrhea on the coagulation status of patients with vitamin K antagonists.

Acute diarrhea is associated with a reduced absorption of both vitamin K antagonists (VKA) and vitamin K itself. To date, the net effect on the coagulation status of subjects with VKA remains elusive. We performed a systematic retrospective single-center analysis using an electronic data extraction approach to identify subjects with plasmatic anticoagulation (either VKA or direct oral anticoagulant (DOAC)) and diarrhea in a German University Hospital over a period of eight years. Acute diarrhea and complete documentation of coagulation status on admission were defined as inclusion criteria, anticoagulation other than VKA/DOAC and obvious inadherence as exclusion criteria. Subjects with VKA/DOAC admitted for hypertension served as control group. Data extraction yielded 356 subjects with gastrointestinal diagnoses and 198 hypertensive subjects, 55 and 83 of whom fulfilled all in- and exclusion criteria. INR values of subjects with VKA were significantly higher in subjects with diarrhea than in hypertensive controls (4.3 ± 3.7 vs. 2.3 ± 0.7, p < 0.001). The distribution of subjects having INR values lower, higher or within the target range differed significantly among groups with a substantially higher prevalence of overanticoagulation in the diarrhea group (46.4% vs. 14.3%, p < 0.001). In a multinomial logistic regression model, acute diarrhea was significantly associated with overanticoagulation (odds ratio 7.2, 95% confidence interval 2.163-23.921; p < 0.001), whereas age, sex, creatinine, and indication of anticoagulation were not (p > 0.05 each). Acute diarrhea is associated with a highly increased risk for overanticoagulation in patients with VKA. Thus, gastroenteritis necessitates a close monitoring of INR in order to identify subjects needing a temporary pause of VKA therapy.

The differential impact of aerobic and isometric handgrip exercise on blood pressure variability and central aortic blood pressure.

BACKGROUND: Blood pressure variability and central SBP are independent markers of cardiovascular risk. Data on lifestyle-interventions to reduce these parameters are sparse. The present work reports the differential effects of aerobic vs. isometric handgrip exercise on blood pressure variability and central SBP in a prospective randomized trial. METHODS: Seventy-five hypertensive patients were randomized to one of the following 12-week programs: isometric handgrip training five times weekly; 'Sham-handgrip training' five times weekly; aerobic exercise training (30 min three to five times/week). Blood pressure variability was assessed by the coefficient of variation in 24-h ambulatory blood pressure monitoring (ABPM). Central SBP was measured noninvasively by the SphygmoCor device (AtCor Medical, Australia). RESULTS: The aerobic exercise program significantly decreased systolic daytime variability (12.1 ±â€Š2.5 vs. 10.3 ±â€Š2.8, P = 0.04), whereas diastolic daytime blood pressure variability was not significantly altered (P = 0.14). Night-time variability was not significantly affected (P > 0.05). Central SBP was reduced from 145±15 to 134 ±â€Š19 mmHg (P = 0.01). Isometric handgrip and sham-handgrip exercise did not significantly affect blood pressure variability (P > 0.05 each). Isometric exercise tended to reduce central SBP (142 ±â€Š19 to 136 ±â€Š17 mmHg, P = 0.06). ANCOVA revealed significant intergroup differences for the change of daytime SBP and DBP variability (P = 0.048 and 0.047, respectively). CONCLUSION: Aerobic exercise reduces blood pressure variability and central SBP. Isometric handgrip exercise does not reduce blood pressure variability but tends to lower central SBP in this hypertensive population.