Generation of potentially inhibitory autoantibodies to ADAMTS13 in coronavirus disease 2019.

It has recently been shown that von Willebrand factor (VWF) multimers contribute to immunothrombosis in Coronavirus disease 2019 (COVID-19). Since COVID-19 is associated with an increased risk of autoreactivity, the present study investigates, whether the generation of autoantibodies to ADAMTS13 contributes to this finding. In this observational prospective controlled multicenter study blood samples and clinical data of patients hospitalized for COVID-19 were collected from April to November 2020. The study included 156 individuals with 90 patients having confirmed COVID-19 of mild to critical severity. 30 healthy individuals and 36 critically ill ICU patients without COVID-19 served as controls. ADAMTS13 antibodies occurred in 31 (34.4%) COVID-19 patients. Antibodies occurred more often in critically ill COVID-19 patients (55.9%) than non-COVID-19 ICU patients and healthy controls (5.6% and 6.7%; p < 0.001), respectively. Generation of ADAMTS13 antibodies in COVID-19 was associated with lower ADAMTS13 activity (56.5%, interquartile range (IQR) 21.25 vs. 71.5%, IQR 24.25, p = 0.0041), increased disease severity (severe or critical in 90% vs. 62.3%, p = 0.019), and a trend to higher mortality (35.5% vs. 18.6%, p = 0.077). Median time to antibody development was 11 days after first positive SARS-CoV-2-PCR specimen. Gel analysis of VWF multimers resembled the constellation in patients with TTP. The present study demonstrates for the first time, that generation of ADAMTS13 antibodies is frequent in COVID-19, associated with lower ADAMTS13 activity and increased risk of an adverse disease course. These findings provide a rationale to include ADAMTS13 antibodies in the diagnostic workup of SARS-CoV-2 infections.

Urinary biomarkers to predict acute kidney damage and mortality in COVID-19.

INTRODUCTION: Acute kidney injury (AKI) is a frequent condition in patients hospitalized for COVID-19. There are only a few reports on the use of urinary biomarkers in COVID-19 and no data so far comparing the prognostic use of individual biomarkers in the prediction of adverse outcomes. MATERIALS AND METHODS: We performed a prospective mono-centric study on the value of urinary biomarkers in predicting the composite endpoint of a transfer to the intensive care unit, the need for renal replacement therapy, mechanical ventilation, and in-hospital mortality. 41 patients hospitalized for COVID-19 were enrolled in this study. Urine samples were obtained shortly after admission to assess neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), calprotectin, and vascular non-inflammatory molecule-1 (vanin-1). RESULTS: We identified calprotectin as a predictor of a severe course of the disease requiring intensive care treatment (AUC 0.728, p = 0.016). Positive and negative predictive values were 78.6% and 76.9%, respectively, using a cut-off concentration of 127.8 ng/mL. NGAL tended to predict COVID-19-associated AKI without reaching statistical significance (AUC 0.669, p = 0.053). The best parameter in the prediction of in-hospital mortality was NGAL as well (AUC 0.674, p = 0.077). KIM-1 and vanin-1 did not reach significance for any of the investigated endpoints. CONCLUSION: While KIM-1 and vanin-1 did not provide prognostic clinical information in the context of COVID-19, the present study shows that urinary calprotectin is moderately predictive of the need for intensive care unit (ICU) admission, and NGAL may be modestly predictive of AKI in COVID-19. Calprotectin and NGAL show promise as potential helpful adjuncts in the identification of patients at increased risk of poor outcomes or complications in COVID-19.

Effect of Nephrectomy After Allograft Failure on Inflammation, Erythropoiesis, Donor-Specific Antibodies, and Outcome of Re-Transplantation.

BACKGROUND Morbidity and mortality rates are high for patients returning to dialysis after renal graft failure. Keeping failed kidney transplants in situ with concomitant minimization or withdrawal of immunosuppression is standard of care in many transplant centers. It is unclear, however, whether the resulting allospecific immune response can cause a microinflammatory milieu. The present work investigated the impact of allograft nephrectomy on systemic inflammation, erythropoiesis, and donor-specific antibodies (DSA). MATERIAL AND METHODS We performed a retrospective analysis evaluating C-reactive protein (CRP), hemoglobin concentration (Hb), ferritin, iron substitution dosages, erythropoietin dosages, and DSA in 92 transplant recipients with allograft failure, of whom 49 did not (Group A) and 43 did undergo transplant nephrectomy (Group B). Blood samples and clinical data were obtained 3-6 months after returning to dialysis. We additionally assessed outcome of kidney re-transplantation in a 10-year follow-up. RESULTS There was no significant difference in Hb concentrations, ferritin concentrations, CRP concentrations, iron, and EPO substitution dosages between the 2 groups. Patients undergoing nephrectomy had a significantly higher prevalence of DSA (65.1% vs 38.8%, P<0.0001). In the 10-year follow-up, 3 patients (12%) of Group B and none in Group A had allograft failure after primary successful re-transplantation. CONCLUSIONS Keeping a kidney graft in situ after returning to dialysis did not lead to an increase in microinflammation. Although DSA develops in more than 50% of patients after an allograft nephrectomy, the outcome of a renal re-transplantation seems to be unaffected. Thus, both strategies are feasible options in kidney transplant recipients after return to dialysis.

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.

Predictors of impaired SARS-CoV-2 immunity in healthcare workers after vaccination with BNT162b2.

Healthcare workers are at substantially increased risk for infection with SARS-CoV-2. Successful vaccination constitutes a crucial prerequisite to protect this group during the pandemic. Since post vaccination antibody monitoring is not standard of care in all healthcare institutions, data on risk factors of impaired vaccine induced immune response are urgently required. Moreover, there are no data on cellular immune responses in humoral low responders so far. Anti-SARS-CoV-2 spike IgG was assessed after vaccination with BNT162b2 in 1386 employees of three hospitals of a German healthcare provider. Concentrations were compared to those of 45 convalescent employees. Vaccine-induced cellular immunity was measured in employees with reduced humoral response by assessment of frequencies of SARS-CoV-2-reactive CD4+ and CD8+ T cell. Anti-SARS-CoV-2 spike IgG were detected in 99.9% of 1386 healthcare workers after completed vaccination. The median antibody concentration was significantly higher after vaccination than after infection with SARS-CoV-2 (p = 0.0001). 10 subjects (0.7%) generated an IgG concentration < 100 IU/ml, and only two persons (0.1%, solid organ recipients) did not produce detectable antibodies at all. T cell responses of those subjects with submaximal or lacking humoral response were comparable to employees with maximal antibody titers. 50% of those individuals with impaired or lacking humoral immune response were on immunosuppression. Vaccination to SARS-CoV-2 with BNT162b2 is very effective in healthcare workers yielding a seroconversion rate of 99.9%. Immunosuppression is the most important risk factor of an impaired immune response. There was no case of vaccination failure without immunosuppression. Thus, post vaccination antibody monitoring is highly recommendable in those employees with immunosuppression.

Low-density lipoprotein apheresis is associated with removal of SARS-CoV-2 antibodies.

BACKGROUND: Low-density lipoprotein apheresis is not specific to lipoproteins but removes immunoglobulins as well. It remains elusive, whether protective SARS-CoV-2 antibodies after vaccination from COVID-19 are eliminated as well. METHODS: A cross-sectional case-control study on 55 patients undergoing weekly lipoprotein apheresis and 21 patients with comparable comorbidities and epidemiology not undergoing apheresis. SARS-CoV-2 IgG was assessed in all patients prior to apheresis and in 38 patients both before and after apheresis. RESULTS: SARS-CoV-2 IgG concentrations before a session of lipoprotein apheresis were comparable to control patients not undergoing apheresis(1727 IU/ml, IQR 365-2500) vs. 1652 IU/ml,(IQR408.8-2500), p = 0.78). SARS-CoV-2 IgG concentrations were reduced by lipoprotein apheresis from 1656 IU/ml(IQR 540.5-2500) prior to 1305 IU/ml (IQR 449-2500) afterwards(p < 0.0001). CONCLUSION: Lipoprotein apheresis removes SARS-CoV-2 IgG. The average elimination rate was 21.2%. In the present population of patients undergoing apheresis once weekly, however, the elimination did not lead to inferior concentrations compared to patients not undergoing lipoprotein apheresis.

The impact of treatment of periodic limb movements in sleep on blood pressure in patients with and without sleep apnea.

Improving sleep quality in patients with obstructive sleep apnea (OSA) by positive airway pressure therapy is associated with a decrease of blood pressure (BP). It remains elusive, whether treatment of sleep disturbances due to restless legs syndrome with symptomatic periodic limb movements in sleep (PLMS) affects BP as well. The present study provides first data on this issue. Retrospective study on patients undergoing polysomnography in a German University Hospital. Inclusion criteria were first diagnosis of restless legs syndrome with PLMS (PLM index ≥ 15/h and PLM arousal index ≥ 5/h) with subsequent initiation of levodopa/benserazide or dopamine agonists. Exclusion criterion was an initiation or change of preexisting positive airway pressure therapy between baseline and follow-up. BP and Epworth sleepiness scale were assessed at two consecutive polysomnographies. After screening of 953 PLMS data sets, 114 patients (mean age 62.1 ± 12.1 years) were included. 100 patients (87.7%) were started on levodopa/benserazide, 14 patients (12.2%) on dopamine agonists. Treatment was associated with significant reductions of PLM index (81.2 ± 65.0 vs. 39.8 ± 51.2, p < 0.001) and ESS (6 [interquartile range, IQR, 3-10.5] vs. 5 [IQR 3-10], p = 0.013). Systolic BP decreased from 132.9 ± 17.1 to 128.0 ± 15.8 mmHg (p = 0.006), whereas there was no significant change of diastolic BP (76.7 ± 10.9 vs. 75.1 ± 9.2 mmHg, p = 0.15) and heart rate (71.5 ± 11.9 vs. 71.3 ± 12.7, p = 0.84). The number of antihypertensive drugs remained unchanged with a median of 2 (IQR 1-3, p = 0.27). Dopaminergic treatment of PLMS is associated with an improvement of sleep quality and a decrease of systolic BP comparable to treatment OSA.

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.

Feasibility of non-invasive measurement of central blood pressure and arterial stiffness in shock.

BACKGROUND: Patients in haemodynamic shock are in need for an intensive care treatment. Invasive haemodynamic monitoring is state of the art for these patients. However, evolved, non-invasive blood pressure monitoring devices offer advanced functions like the assessment of central blood pressure and arterial stiffness. We analysed the feasibility of two oscillometric blood pressure devices in patients with shock. METHODS: We performed a monocentre prospective study, enrolling 57 patients admitted to the intensive care unit (ICU), due to septic and/or cardiogenic shock. We assessed invasive and non-invasive peripheral and central blood pressure <24 hours and 48 hours after admission on the ICU. Additional haemodynamic parameters such as pulse wave velocity (PWV), augmentation pressure and augmentation index were obtained through Mobil-o-Graph PWA (IEM) and SphygmoCor XCEL (AtCor Medical). RESULTS: A complete haemodynamic assessment was successful in all patients (48) with the Mobil-o-Graph 24 hours PWA and in 29 patients with the SphygmoCor XCEL (P = .001), when cases of death or device malfunction were excluded. Reasons for failure were severe peripheral artery disease, haemodynamic instability, oedema and agitation. Invasive blood pressure showed a sufficient correlation with both devices; however, large differences between invasive and non-invasive techniques were recorded in Bland-Altmann analysis (P < .05 for all parameters). PWV differed between the two devices. CONCLUSION: Non-invasive peripheral blood pressure measurement remains a rescue technique. However, non-invasive assessment of arterial stiffness and central blood pressure is possible in patients with septic or cardiogenic shock. Further studies are required to assess their clinical significance for patients in shock.

Biopsy findings after detection of de novo donor-specific antibodies in renal transplant recipients: a single center experience.

BACKGROUND: De novo donor-specific antibodies (DSA) are associated with an increased risk of antibody-mediated rejection and a substantial reduction of allograft survival. We hypothesized that detection of DSA should prompt a biopsy even in the absence of proteinuria and loss of estimated glomerular filtration rate (eGFR). However, data on a population without proteinuria or loss of kidney function is scant, and this is the main novelty of our study design. METHODS: Single center retrospective analysis on biopsy findings after detection of de novo DSA. One-hundred-thirty-two kidney and pancreas-kidney transplant recipients were included. Eighty-four of these patients (63.6%) underwent allograft biopsy. At the time of biopsy n = 50 (59.5%) had a protein/creatinine ratio (PCR) > 300 mg/g creatinine and/or a loss of eGFR ≥ 10 ml/min in the previous 12 months, whereas 40.5% did not. Diagnosis of rejection was performed according to Banff criteria. RESULTS: Seventy-seven (91.7%) of the biopsies had signs of rejection (47.6% antibody mediated rejection (ABMR), 13.1% cellular, 20.2% combined, 10.7% borderline). Among subjects without proteinuria or loss of eGFR ≥ 10 ml/min/a (n = 34), 29 patients (85.3%) showed signs of rejection (44.1% antibody mediated (ABMR), 14.7% cellular, 11.8% combined, 14.7% borderline). CONCLUSION: The majority of subjects with de novo DSA have histological signs of rejection, even in the absence of proteinuria and deterioration of graft function. Thus, it appears reasonable to routinely perform an allograft biopsy after the detection of de novo DSA.

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.

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.

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.

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.

Dickkopf-3 in the prediction of contrast media induced acute kidney injury.

BACKGROUND: Dickkopf-3 (DKK3) has recently been discovered as a urinary biomarker for the prediction of acute kidney injury (AKI) after cardiac surgery. This finding needs to be confirmed for AKI in other clinical settings. The present study investigates whether DKK3 can predict contrast-induced AKI (CI-AKI). METHODS: We performed a prospective study in 490 patients undergoing coronary angiography. Primary endpoint was an increase in serum creatinine concentration ≥ 0.3 mg/dl within 72 h after the procedure. DKK3 was assessed < 24 h before coronary angiography. Predictive accuracy was assessed by receiver operating characteristic (ROC) curves. RESULTS: CI-AKI was observed in 30 (6.1%) patients, of whom 27 corresponded to stage I and 3 to stage II according to the Acute Kidney Injury Network (AKIN) criteria. Subjects who developed CI-AKI had a 3.8-fold higher urinary DKK3/creatinine ratio than those without CI-AKI (7.5 pg/mg [interquartile range [IQR] 1.2-1392.0] vs. 2.0 pg/mg [IQR 0.9-174.0]; p = 0.047). ROC analysis revealed an area under the curve (AUC) of 0.61. Among subjects without clinically overt chronic kidney disease (estimated glomerular filtration rate [eGFR] > 60 ml/min, urinary albumin creatinine ratio < 30 mg/g), the DKK3/creatinine ratio was 5.4-fold higher in those with subsequent CI-AKI (7.5 pg/mg [IQR 0.9-590.1] vs. 1.38 pg/mg [IQR 0.8-51.0]; p = 0.007; AUC 0.62). Coronary angiography was associated with a 43 times increase in the urinary DKK3/creatinine ratio. CONCLUSIONS: Urinary DKK3 is an independent predictor of CI-AKI even in the absence of overt chronic kidney disease (CKD). The study thereby expands the findings on DKK3 in the prediction of postoperative loss of kidney function to other entities of AKI.

Detection of SARS-CoV-2 pneumonia: two case reports.

BACKGROUND: Developing therapeutic strategies for a SARS-CoV-2 infection is challenging, but first the correct diagnosis has to be made. Unspecific upper and lower respiratory tract symptoms can be misleading; hence, a nasopharyngeal swab test with a real-time reverse-transcription-polymerase chain reaction is of great importance. However, early viral clearing jeopardizes a sound diagnosis of COVID-19. CASE PRESENTATION: We report on two Caucasian patients who had negative pharyngeal swab tests at the onset of SARS-CoV-2 pneumonia. In one patient, the virus was not even detectable in bronchoalveolar lavage despite typical radiomorphologic changes. CONCLUSIONS: Negative PCR findings in both the pharynx and bronchoalveolar lavage do not exclude COVID-19 pneumonia. Computed tomography is a crucial diagnostic prerequisite in this context.

Psychological Responses to the Coronavirus Disease 2019 Pandemic in Renal Transplant Recipients.

BACKGROUND: Renal transplant recipients are at increased risk for an adverse course of coronavirus disease 2019 (COVID-19), most likely due to immunosuppression and the high level of cardiovascular comorbidity. Many transplant recipients are aware of these facts. The psychological effects of this knowledge, however, remain elusive. METHODS: Cross-sectional study on 62 renal transplant recipients. Fifty cardiovascular outpatients without immunosuppression and 55 healthy subjects served as control. We performed a focused psychological assessment during the pandemic (April 2020) and compared the data with a time 6 months before. Additionally, an intergroup analysis was performed for the data during the pandemic. The analysis was performed by means of a questionnaire derived from KPD-38. We extracted 5 questions focusing on the parameters "life satisfaction" and perceived "action competence." Life satisfaction score ranged from 2 to 8, and the score for action competence from 5 to 20. RESULTS: Both life satisfaction and perceived action competence were significantly lower during the pandemic than 6 months before in all the 3 groups (P < .005 each). During the pandemic median levels of life satisfaction did not significantly differ between the 3 groups (transplant recipients 6, interquartile range [IQR] 4-7; cardiovascular patients 5, IQR: 4-6; healthy controls 6, IQR 5-7; Kruskal-Wallis P > .05). In contrast, the perceived action competence was higher in healthy subjects (15, IQR 12-17) than in both renal transplant recipients (13, IQR 10-15) and cardiovascular patients (13, IQR 8-14, Kruskal-Wallis P = .0003). CONCLUSION: The COVID-19 pandemic has negative effects on life satisfaction and perceived action competence in renal transplant recipients, cardiovascular patients without immunosuppression, and healthy subjects. The effects on life satisfaction in transplant recipients did not differ from nonimmunocompromised patients or healthy controls. In contrast, the feeling of reduced action competence exceeded healthy controls, most likely due to a subjective need for stricter social distancing to avoid infection.

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.

Lessons for the clinical nephrologist: recurrence of nephrotic syndrome induced by SARS-CoV-2.

SARS-CoV-2 is characterized by a multiorgan tropism including the kidneys. Recent autopsy series indicated that SARS-CoV-2 can infect both tubular and glomerular cells. Whereas tubular cell infiltration may contribute to acute kidney injury, data on a potential clinical correlative to glomerular affection is rare. We describe the first case of nephrotic syndrome in the context of COVID-19 in a renal transplant recipient. A 35 year old male patient received a kidney allograft for primary focal segmental glomerulosclerosis (FSGS). Three months posttransplant a recurrence of podocytopathy was successfully managed by plasma exchange, ivIG, and a conversion from tacrolimus to belatacept (initial proteinuria > 6 g/l decreased to 169 mg/l). Six weeks later he was tested positive for SARS-CoV-2 and developed a second increase of proteinuria (5.6 g/l). Renal allograft biopsy revealed diffuse podocyte effacement and was positive for SARS-CoV-2 in RNA in-situ hybridation indicating a SARS-CoV-2 associated recurrence of podocytopathy. Noteworthy, nephrotic proteinuria resolved spontaneously after recovering from COVID-19. The present case expands the spectrum of renal involvement in COVID-19 from acute tubular injury to podocytopathy in renal transplant recipients. Thus, it may be wise to test for SARS-CoV-2 prior to initiation of immunosuppression in new onset glomerulopathy during the pandemic.