TNF or EGFR inhibition equally block AKI-to-CKD transition: opportunities for etanercept treatment.

BACKGROUND: Inflammation is a key driver of the transition of acute kidney injury to progressive fibrosis and chronic kidney disease (AKI-to-CKD transition). Blocking a-disintegrin-and-metalloprotease-17 (ADAM17)-dependent ectodomain shedding, in particular of epidermal growth factor receptor (EGFR) ligands and of the type 1 inflammatory cytokine tumor necrosis factor (TNF), reduces pro-inflammatory and pro-fibrotic responses after ischemic AKI or unilateral ureteral obstruction (UUO), a classical fibrosis model. Metalloprotease or EGFR inhibition show significant undesirable side effects in humans. In retrospective studies anti-TNF biologics reduce the incidence and progression of CKD in humans. Whether TNF has a role in AKI-to-CKD transition and how TNF inhibition compares to EGFR inhibition is largely unknown. METHODS: Mice were subjected to bilateral renal ischemia-reperfusion injury or unilateral ureteral obstruction. Kidneys were analyzed by histology, immunohistochemistry, qPCR, western blot, mass cytometry, scRNA sequencing, and cytokine profiling. RESULTS: Here we show that TNF or EGFR inhibition reduce AKI-to-CKD transition and fibrosis equally by about 25%, while combination has no additional effect. EGFR inhibition reduced kidney TNF expression by about 50% largely by reducing accumulation of TNF expressing immune cells in the kidney early after AKI, while TNF inhibition did not affect EGFR activation or immune cell accumulation. Using scRNAseq data we show that TNF is predominantly expressed by immune cells in AKI but not in proximal tubule cells (PTC), and PTC-TNF knockout did not affect AKI-to-CKD transition in UUO. Thus, the anti-inflammatory and anti-fibrotic effects of the anti-TNF biologic etanercept in AKI-to-CKD transition rely on blocking TNF that is released from immune cells recruited or accumulating in response to PTC-EGFR signals. CONCLUSION: Short-term anti-TNF biologics during or after AKI could be helpful in the prevention of AKI-to-CKD transition.

HMGB1 Is a Prognostic Factor for Mortality in Acute Kidney Injury Requiring Renal Replacement Therapy.

INSTRUCTION: High mobility group box 1 (HMGB1) is a pro-inflammatory cytokine that reportedly causes kidney injury and other organ damage in rodent acute kidney injury (AKI) models. However, it remains unclear whether HMGB1 is associated with clinical AKI and related outcomes. This study aimed to evaluate the association with HMGB1 and prognosis of AKI requiring continuous renal replacement therapy (CRRT). METHODS: AKI patients treated with CRRT in our intensive care unit were enrolled consecutively during 2013-2016. Plasma HMGB1 was measured on initiation. Classic initiation was defined as presenting at least one of the following conventional indications: hyperkalemia (K ≥6.5 mEq/L), severe acidosis (pH <7.15), uremia (UN >100 mg/dL), and diuretics-resistant pulmonary edema. Early initiation was defined as presenting no conventional indications. The primary outcome was defined as 90-day mortality. RESULTS: A total of 177 AKI patients were enrolled in this study. HMGB1 was significantly associated with the primary outcome (hazard ratio, 1.06; 95% CI, 1.04-1.08). When the patients were divided into two-by-two groups by the timing of CRRT initiation and the HMBG1 cutoff value obtained by receiver operating curve (ROC) analysis, the high HMGB1 group (>10 ng/mL) with classic initiation was significantly associated with the primary outcome compared with the others, even after adjusting for other factors including the nonrenal serial organ failure assessment (SOFA) score. CONCLUSION: HMGB1 was associated with 90-day mortality in AKI patients requiring CRRT. Notably, the highest mortality was observed in the high HMGB1 group with classic initiation. These findings suggest that CRRT should be considered for AKI patients with high HMGB1, regardless of the conventional indications.

Different Roles of Functional and Structural Renal Markers Measured at Discontinuation of Renal Replacement Therapy for Acute Kidney Injury.

INTRODUCTION: Severe acute kidney injury (AKI) requiring renal replacement therapy (RRT) has been associated with an unacceptably high mortality of 50% or more. Successful discontinuation of RRT is thought to be linked to better outcomes. Although functional and structural renal markers have been evaluated in AKI, little is known about their roles in predicting outcomes at the time of RRT discontinuation. METHODS: In this prospective single-center cohort study, we analyzed patients who received continuous RRT (CRRT) for AKI between August 2016 and March 2018 in the intensive care unit of the University of Tokyo Hospital (Tokyo, Japan). Clinical parameters and urine samples were obtained at CRRT discontinuation. Successful CRRT discontinuation was defined as neither resuming CRRT for 48 h nor receiving intermittent hemodialysis for 7 days from the CRRT termination. Major adverse kidney events (MAKEs) were defined as death, requirement for dialysis, or a decrease in the estimated glomerular filtration rate (eGFR) of more than 25% from the baseline at day 90. RESULTS: Of 73 patients, who received CRRT for AKI, 59 successfully discontinued CRRT and 14 could not. Kinetic eGFR, urine volume, urinary neutrophil gelatinase-associated lipocalin (NGAL), and urinary L-type fatty acid binding protein were predictive for CRRT discontinuation. Of these factors, urine volume had the highest area under the curve (AUC) 0.91 with 95% confidence interval [0.80-0.96] for successful CRRT discontinuation. For predicting MAKEs at day 90, the urinary NGAL showed the highest AUC 0.76 [0.62-0.86], whereas kinetic eGFR and urine volume failed to show statistical significance (AUC 0.49 [0.35-0.63] and AUC 0.59 [0.44-0.73], respectively). CONCLUSIONS: Our prospective study confirmed that urine volume, a functional renal marker, predicted successful discontinuation of RRT and that urinary NGAL, a structural renal marker, predicted long-term renal outcomes. These observations suggest that the functional and structural renal makers play different roles in predicting the outcomes of severe AKI requiring RRT.

Plasma xanthine oxidoreductase is associated with carotid atherosclerosis in stable kidney transplant recipients.

AIM: Xanthine oxidoreductase (XOR) is known as an enzyme related to purine metabolism, catalysing the oxidation of hypoxanthine to xanthine and of xanthine to uric acid. We investigated the relationship between plasma XOR activity in stable kidney transplantation (KT) recipients and carotid artery lesions. METHODS: A total of 42 KT patients visiting our outpatient clinic on regular basis were recruited. Associations between plasma XOR activity and the existence of plaque in the common carotid artery (CCA) or internal carotid artery (ICA) and maximum intima-medial thickness (IMT) of CCA (max-CIMT) > 0.9 mm were examined using univariate and multivariate analyses. RESULTS: At blood sampling, the mean and SD patient age was 52.7 ± 13.8 years old. Plasma XOR(pmol/h/ml) activity was significantly higher in patients with CCA/ICA plaque or max-CIMT >0.9 mm than those without. [23.9 (11.8, 38.3) vs. 8.29 (6.67, 17.5), p < .01, 23.9 (16.9, 71.2) vs. 9.16 (6.67, 28.2), p = .01] Univariate and multivariate logistic regression analyses revealed age and plasma XOR activity as independent predictors of CCA/ICA plaque or max-CIMT >0.9 mm. Receiver operator characteristic curve analyses revealed that the cutoff value of plasma XOR activity for the diagnosis of CCA/ICA plaque or CCA-IMT > 0.9 mm was 16.3 pmol/h/ml. CONCLUSION: Plasma XOR activity is associated independently with atherosclerotic changes in the carotid artery of stable post-KT patients.

Prognostic significance of concentric left ventricular hypertrophy at peritoneal dialysis initiation.

BACKGROUND: Concentric left ventricular hypertrophy (cLVH) is a common left ventricular geometric pattern in patients undergoing maintenance dialysis, including peritoneal dialysis (PD). The relationship between cLVH at PD initiation and the prognosis of patients remains unclear, however. This study aimed to investigate the impact of cLVH at PD initiation on patient survival and major adverse cardiovascular events (MACE). METHODS: The retrospective cohort study included 131 patients who underwent echocardiography during the PD initiation period. Based on echocardiographic measurements, cLVH was defined as a condition with increased LV mass index and increased relative wall thickness. The relationship between cLVH and the prognosis was assessed. RESULTS: Concentric LVH was identified in 29 patients (22%) at PD initiation, and patient survival, MACE-free survival and PD continuation were significantly reduced in the cLVH group compared with the non-cLVH group. In the Cox regression analysis, cLVH was demonstrated as an independent risk factor of mortality (HR [95%CI]: 3.32 [1.13-9.70]) for all patients. For patients over 65 years old, cLVH was significantly associated with mortality and MACE (HR [95%CI]: 3.51 [1.06-11.58] and 2.97 [1.26-7.01], respectively). Serum albumin at PD initiation was independently correlated with cLVH. CONCLUSIONS: In our study, cLVH at PD initiation was independently associated with survival in all patients and with both survival and MACE in elderly patients. Evaluation of LV geometry at PD initiation might therefore help identify high-risk patients. Further studies involving larger numbers of patients are needed to confirm the findings from this study and clarify whether treatment interventions for factors such as nutrition status could ameliorate cLVH and improve patient outcomes.

Correlation between the Incidence and Attributable Mortality Fraction of Acute Kidney Injury: A Systematic Review.

INTRODUCTION: The incidence of acute kidney injury (AKI) as diagnosed by international standardized criteria as well as its mortality has undergone extreme variations. Although AKI is a significant worsening mortality factor, a higher prevalence may lead to better patient management, thereby lowering mortality. We investigated the correlation between AKI incidence and its associated mortality. METHODS: We conducted a systematic review of studies on AKI reporting its incidence and mortality. Literature searches were performed in -MEDLINE, EMBASE, and Cochrane Library, within the time frame of 2004-2018. Studies with small number of participants (<500 for adult cohorts, 50 for pediatric cohorts) were excluded. The correlation among AKI incidence, mortality, and AKI-attributable fraction of mortality was evaluated using a regression model. The trend test was used to analyze the effect of publication year and country gross domestic product (GDP). RESULTS: A total of 4,694 manuscripts were screened, from which 287 cohorts were eligible (adults: 203 cohorts comprising 7,076,459 patients; children: 84 comprising 69,677 patients). Within adult cohorts, AKI patients' mortality increased (R2 = 0.023, ß = 0.12, p = 0.03) but the attributable fraction of mortality decreased (R2 = 0.27, ß = -0.43, p < 0.001) with the increasing AKI incidence. Both more recent publications and higher GDP countries had a lower crude AKI patients' mortality, although AKI-attributable fraction did not decrease. CONCLUSIONS: Cohorts with high AKI incidence had a relatively low AKI-attributable mortality fraction, which suggests an advantage of more experienced AKI management. Further study is needed, however, to address the heterogeneity of included cohorts and to confirm the causality. (Registered in prospective register of systematic reviews database; CRD 42019129322.).

Urinary chloride concentration as a prognostic marker in critically ill patients.

AIM: Associations have been reported among serum chloride concentration, mortality and incidence of acute kidney injury (AKI) in intensive care units (ICU). This study aimed to examine associations among urinary chloride, mortality, and AKI incidence in ICU patients. METHODS: A retrospective observational study was conducted among medical-surgical ICU in a tertiary hospital wherein 170 consecutive ICU patients were evaluated from October 2015 to March 2016 and 116 patients were enrolled. Serial data of serum and urine electrolytes from day 1 to day 4 of ICU admission were examined. The primary and secondary outcomes were ICU mortality and incidence of AKI in the ICU, respectively. RESULTS: Among the 116 enrolled patients, 15 (13%) died during their ICU stay. Although serum and urinary sodium and potassium on day 1 did not significantly differ between ICU survivors and non-survivors, urinary chloride concentration on day 1 was significantly lower in non-survivors. Receiver operating characteristic analysis showed that the cutoff value of day 1 urinary chloride concentration for prediction of ICU mortality was 53 mEq/L. The lower urinary chloride concentration group on day 1 showed a significantly lower survival rate, even in long-term follow-up, compared with the higher urinary chloride group. Addition of day 1 urinary chloride concentration improved prediction of AKI incidence in the ICU by Sequential Organ Failure Assessment score alone. CONCLUSION: Lower urinary chloride concentration was associated with increased mortality and incidence of AKI in the ICU. Further investigation is necessary to clarify the mechanism of urinary chloride regulation.

Kinetic estimated glomerular filtration rate as a predictor of successful continuous renal replacement therapy discontinuation.

AIM: No standardized criteria for continuous renal replacement therapy (CRRT) discontinuation have been established. Kinetic estimated glomerular filtration rate (eGFR) is a newly developed estimation method based on dynamic changes of serum creatinine expected to reflect the true GFR. This study aimed to evaluate the predictive role of kinetic eGFR for CRRT discontinuation. METHODS: A retrospective single-centre cohort study was conducted. Acute kidney injury (AKI) patients who received CRRT between May 2015 and April 2016 were enrolled. Successful CRRT discontinuation was defined as neither resuming CRRT for the next 48 h nor receiving intermittent haemodialysis 7 days from the CRRT discontinuation. Clinical factors associated with CRRT discontinuation were evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: Of 52 AKI patients treated with CRRT, 38 could discontinue CRRT while 14 could not. Urine volume, regular and kinetic eGFR of days 0 (day of CRRT discontinuation) and 1 were all good predictive parameters (area under the ROC curve (AUC) > 0.7). Kinetic eGFR of day 1 showed the AUC of 0.87 [95% confidence interval 0.73-0.94]). Combining kinetic eGFR of day 1 and urine volume of day 0 gave a high AUC of 0.93 [95% confidence interval 0.82-0.97]. The combination was significantly greater than urine volume of day 0 (P = 0.008). CONCLUSION: Kinetic eGFR combined with urine volume was a better predictor for CRRT discontinuation. Evaluation of kinetic eGFR utility in other clinical settings will be necessary.

Nephritis-associated plasmin receptor (NAPlr) positive glomerulonephritis caused by Aggregatibacter actinomycetemcomitans bacteremia: A case report.

Infection-related glomerulonephritis (IRGN) develops after various infections. It was previously thought to be caused by Streptococcus species alone but can also be caused by other pathogens. Nephritis-associated plasmin receptor (NAPlr) was discovered as a candidate nephritis-inducing factor in acute post-streptococcal glomerulonephritis. More recently, renal lesions caused by other pathogens were found to be positive for the same molecular marker. We report the case of a 64-year-old man who experienced repeated fever for several months and presented with progressively-deteriorating renal function. He had previously undergone aortic valve replacement. Aggregatibacter actinomycetemcomitans, a component of the oral flora, was detected in a blood culture. Renal biopsy showed diffuse proliferative glomerulonephritis. Immunofluorescence staining of the kidney specimen was positive for immunoglobulins, complements, and NAPlr. The patient was diagnosed with infectious endocarditis and IRGN. Six weeks of intravenous antibiotic therapy improved the patient's clinical condition and kidney function. In this case, IRGN was caused by a rare pathogen. This is the first published case to show NAPlr positivity in the glomeruli after systemic infection with the periodontal bacteria, Aggregatibacter actinomycetemcomitans. This case and subsequent research might expand the concept of IRGN, anchored by NAPlr as a key diagnostic biomarker.
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A healthy young woman with massive hemorrhagic ascites.

Retrograde menstruation is the backward movement of menstrual fluids. The underlying mechanisms remain unknown. The converse current itself is benign, but the result can be abdominal pain caused by peritoneal irritation and, eventually, endometriosis. The case was of a 25-year-old woman with lower abdominal pain accompanied by significant hemoperitoneum. Physical examination and inspection using abdominal ultrasonography and computed tomography failed to reveal a differential diagnosis. Detailed history taking revealed sexual activities during her menstrual period, which allowed for a diagnosis of retrograde menstruation. These findings emphasize the importance of extensive history taking.

Interorgan communication networks in the kidney-lung axis.

The homeostasis and health of an organism depend on the coordinated interaction of specialized organs, which is regulated by interorgan communication networks of circulating soluble molecules and neuronal connections. Many diseases that seemingly affect one primary organ are really multiorgan diseases, with substantial secondary remote organ complications that underlie a large part of their morbidity and mortality. Acute kidney injury (AKI) frequently occurs in critically ill patients with multiorgan failure and is associated with high mortality, particularly when it occurs together with respiratory failure. Inflammatory lung lesions in patients with kidney failure that could be distinguished from pulmonary oedema due to volume overload were first reported in the 1930s, but have been largely overlooked in clinical settings. A series of studies over the past two decades have elucidated acute and chronic kidney-lung and lung-kidney interorgan communication networks involving various circulating inflammatory cytokines and chemokines, metabolites, uraemic toxins, immune cells and neuro-immune pathways. Further investigations are warranted to understand these clinical entities of high morbidity and mortality, and to develop effective treatments.

Sterile kidney tissue injury induces neutrophil swarming in lung alveolar capillaries.

Sterile tissue injury, such as by acute kidney injury, is common in the clinic and frequently associated with respiratory compromise and hypoxemia. We previously described signaling components released by the injured kidney that drive a remote inflammatory response in the lung. How this caused the resultant hypoxemia remained unclear. Here, we report that sterile kidney tissue injury induces rapid intravascular "neutrophil train" formation in lung capillaries, a novel form of neutrophil swarming. Rapid swarming is enhanced by decreased deformability of circulating neutrophils that impedes their lung capillary passage. Classical lung monocytes are required for neutrophil train formation and release CXCL2 to attract and retain stiffened neutrophils in lung capillaries which reduces capillary perfusion. We thus discovered a novel feature of kidney-lung crosstalk after sterile kidney tissue injury, capillary perfusion deficits that lead to reduced oxygenation despite proper alveolar function and ventilation, unlike in infectious inflammatory lung processes, such as bacterial pneumonia.

Serum myostatin at dialysis initiation may predict 1-year mortality and hospitalization.

OBJECTIVE: Myostatin, which is known as a negative skeleton muscle regulator, is associated with mortality in maintenance hemodialysis patients. However, the significance of serum myostatin concentrations at dialysis initiation has not been established. We investigated the relation between serum myostatin concentrations and mortality or hospitalization within one year in incident dialysis patients. METHODS: After a patient initiating hemodialysis or peritoneal dialysis during 2016-2018 was enrolled, the patient's serum myostatin at dialysis initiation was measured. Composite outcomes comprising mortality and hospitalization within 1 year after dialysis initiation were compared between two groups divided according to myostatin levels. The Cox proportional hazards model was used to assess significant relations between myostatin and outcomes. RESULTS: This study examined 104 incident dialysis patients with mean age of 65.5±14.0 (68% male). Kaplan-Meier analyses indicated the 1-year hospitalization-free and survival rate as significantly lower in the lower myostatin group than in the higher myostatin group (p = .0020). Cox proportional hazards regression analyses revealed that the value of myostatin logarithm at dialysis initiation was inversely associated with the occurrence of a composite outcome, independently of age (hazard ratio 0.16, 95% confidence interval 0.05-0.57). Receiver operating characteristic (ROC) analysis showed the area under the curve of serum myostatin for predicting death or hospitalization within 1 year as higher than those of clinical indices of nutritional disturbance and frailty. CONCLUSION: Serum myostatin concentration at dialysis initiation is inversely associated with adverse outcomes in these dialysis-initiated patients.

BENEFIT OF HIGHER BLOOD PRESSURE TARGET IN SEVERE ACUTE KIDNEY INJURY TREATED BY CONTINUOUS RENAL REPLACEMENT THERAPY.

ABSTRACT: Introduction : The optimal target of mean arterial pressure (MAP) during continuous renal replacement therapy (CRRT) is unknown. Method : We retrospectively collected the hourly MAP data in acute kidney injury patients requiring CRRT who admitted to the intensive care unit in the University of Tokyo hospital during 2011-2019. Patients who died within 48 h of CRRT start and whose average value of hourly MAPs during the first 48 h was <65 mm Hg were excluded. When the average value of MAP was ≤75 mm Hg or >75 mm Hg, patients were allocated to the low or high target group. We estimated the effect of MAP on mortality and RRT independence at 90 days, using multivariable the Cox regression model and Fine and Gray model. Result : Of the 275 patients we analyzed, 95 patients were in the low group. There are no differences in sex, baseline kidney function, and disease severity. At 90 days, the low target group had higher mortality with 38 deaths (40.0%) compared with 57 deaths (31.7%) in the high target group ( P < 0.05). The adjusted hazard ratio of the low target group (≤75 mm Hg) for mortality was 1.72 (95% CI, 1.08-2.74). In addition, the low target group had a lower rate of RRT independence, with 60 patients (63.2%) compared with 136 patients (75.6%) in the high target group ( P < 0.05). The multivariable analysis revealed that the adjusted hazard ratio of the low target group for RRT independence was 0.74 (95% CI, 0.54-1.01). Conclusion : This study found the association with low MAP and mortality. The association with low MAP and delayed renal recovery was not revealed.

Application of urinary biomarkers for diagnosing acute kidney injury in critically ill patients without baseline renal function data.

PURPOSE: Estimating the baseline renal function of patients without prior creatinine measurement is crucial for diagnosing acute kidney injury (AKI). This study aimed to incorporate AKI biomarkers into a new AKI diagnosis rule when no premorbid baseline is available. METHODS: This prospective observational study was conducted in an adult intensive care unit (ICU). Urinary neutrophil gelatinase-associated lipocalin (NGAL) and L-type fatty acid-binding protein (L-FABP) were measured at ICU admission. An AKI diagnostic rule was composed by classification and regression tree (CART) analysis. RESULTS: A total of 243 patients were enrolled. In the development cohort, CART analysis composed a decision tree for AKI diagnosis selecting serum creatinine and urinary NGAL at ICU admission as predictors. In the validation cohort, the novel decision rule was superior to the imputation strategy based on Modification of Diet in Renal Disease (MDRD) equation regarding misclassification rate (13.0% vs. 29.6%, p = 0.002). Decision curve analysis demonstrated that the net benefit of the decision rule exceeded the MDRD approach in a threshold probability range of 25% and higher. CONCLUSIONS: The novel diagnostic rule incorporating serum creatinine and urinary NGAL at ICU admission showed superiority to the MDRD approach in AKI diagnosis without baseline renal function data.

Acute Kidney Injury-Induced Circulating TNFR1/2 Elevations Correlate with Persistent Kidney Injury and Progression to Fibrosis.

Elevated levels of circulating tumor necrosis factor receptors 1 and 2 (cTNFR1/2) predict chronic kidney disease (CKD) progression; however, the mechanisms of their release remain unknown. Whether acute kidney injury (AKI) drives cTNFR1/2 elevations and whether they predict disease outcomes after AKI remain unknown. In this study, we used AKI patient serum and urine samples, mouse models of kidney injury (ischemic, obstructive, and toxic), and progression to fibrosis, nephrectomy, and related single-cell RNA-sequencing datasets to experimentally test the role of kidney injury on cTNFR1/2 levels. We show that TNFR1/2 serum and urine levels are highly elevated in all of the mouse models of kidney injury tested, beginning within one hour post injury, and correlate with its severity. Consistent with this, serum and urine TNFR1/2 levels are increased in AKI patients and correlate with the severity of kidney failure. Kidney tissue expression of TNFR1/2 after AKI is only slightly increased and bilateral nephrectomies lead to strong cTNFR1/2 elevations, suggesting the release of these receptors by extrarenal sources. The injection of the uremic toxin indoxyl sulfate in healthy mice induces moderate cTNFR1/2 elevations. Moreover, TNF neutralization does not affect early cTNFR1/2 elevations after AKI. These data suggest that cTNFR1/2 levels in AKI do not reflect injury-induced TNF activity, but rather a rapid response to loss of kidney function and uremia. In contrast to traditional disease biomarkers, such as serum creatinine or BUN, cTNFR1/2 levels remain elevated for weeks after severe kidney injury. At these later timepoints, cTNFR1/2 levels positively correlate with remaining kidney injury. During the AKI-to-CKD transition, elevations of TNFR1/2 kidney expression and of cTNFR2 levels correlate with kidney fibrosis levels. In conclusion, our data demonstrate that kidney injury drives acute increases in cTNFR1/2 serum levels, which negatively correlate with kidney function. Sustained TNFR1/2 elevations after kidney injury during AKI-to-CKD transition reflect persistent tissue injury and progression to kidney fibrosis.

Solute Clearance Evaluation and Filter Clotting Prediction in Continuous Renal Replacement Therapy.

Unexpected filter clotting is a major problem in continuous renal replacement therapy (CRRT). Reduced solute clearance is observed prior to filter clotting. This single-center, retrospective, observational study aimed to determine whether reduced solute clearance of low- and medium-molecular-weight molecules in CRRT can predict filter clotting. Solute clearances of urea and myoglobin (Mb) were measured at 24 h after initiation of continuous hemodiafiltration (CHDF). Clearance per flow (CL/F) was calculated. The primary outcome was clotting of the filter in the subsequent 24 h, and 775 CHDF treatments conducted on 230 patients for at least 24 consecutive hours in our ICU were analyzed. Filter clotting was observed in 127 treatments involving 39 patients. Urea and Mb CL/F at 24 h were significantly lower in the patients who experienced clotting. Further analysis was limited to the first CHDF treatment of each patient to adjust for confounding factors. Multivariate logistic regression analysis revealed that both urea CL/F < 94% and Mb CL/F < 64% were significant predictors of clotting within the next 24 h. Lower urea and Mb CL/F measured at 24 h after CRRT initiation were associated with filter clotting in the next 24 h. Further study is necessary to ascertain whether measurement of urea and MB CL/F will help with avoiding unexpected filter clotting.

Urinary neutrophil gelatinase-associated lipocalin and plasma IL-6 in discontinuation of continuous venovenous hemodiafiltration for severe acute kidney injury: a multicenter prospective observational study.

BACKGROUND: Patients with severe acute kidney injury (AKI) who require continuous venovenous hemodiafiltration (CVVHDF) in intensive care unit (ICU) are at high mortality risk. Little is known about clinical biomarkers for risk prediction, optimal initiation, and optimal discontinuation of CVVHDF. METHODS: This prospective observational study was conducted in seven university-affiliated ICUs. For urinary neutrophil gelatinase-associated lipocalin (NGAL) and plasma IL-6 measurements, samples were collected at initiation, 24 h, 48 h after, and CVVHDF discontinuation in adult patients with severe AKI. The outcomes were deaths during CVVHDF and CVVHDF dependence. RESULTS: A total number of 133 patients were included. Twenty-eight patients died without CVVHDF discontinuation (CVVHDF nonsurvivors). Urinary NGAL and plasma IL-6 at the CVVHDF initiation were significantly higher in CVVHDF nonsurvivors than in survivors. Among 105 CVVHDF survivors, 70 patients were free from renal replacement therapy (RRT) or death in the next 7 days after discontinuation (success group), whereas 35 patients died or needed RRT again (failure group). Urinary NGAL at CVVHDF discontinuation was significantly lower in the success group (93.8 ng/ml vs. 999 ng/ml, p < 0.01), whereas no significant difference was observed in plasma IL-6 between the groups. Temporal elevations of urinary NGAL levels during the first 48 h since CVVHDF initiation were observed in CVVHDF nonsurvivors and those who failed in CVVHDF discontinuation. CONCLUSIONS: Urinary NGAL at CVVHDF initiation and discontinuation was associated with mortality and RRT dependence, respectively. The serial changes of urinary NGAL might also help predict the prognosis of patients with AKI on CVVHDF.

Pharmacologic suppression of hepatic ATP-binding cassette transporter 1 activity in mice reduces high-density lipoprotein cholesterol levels but promotes reverse cholesterol transport.

BACKGROUND: The role of hepatic ATP-binding cassette transporter 1 (ABCA1) in maintaining plasma high density lipoprotein cholesterol (HDL-C) levels is well established, but its role in reverse cholesterol transport (RCT) is unclear. Probucol is a compound that reduces HDL-C levels but also reduces atherosclerosis in animal models and xanthomas in humans. The aim of the present study was to test the hypothesis that probucol inhibits hepatic ABCA1 activity, thereby reducing HDL-C levels but promoting RCT from macrophages. METHODS AND RESULTS: Wild-type (WT) C57BL/6 mice and scavenger receptor class B type I (SR-BI) knockout mice were fed a chow diet containing 0.5% probucol or normal chow for 2 weeks. In WT mice, probucol, despite decreasing HDL-C by >80%, effectively maintained macrophage RCT. In SR-BI knockout mice, probucol also substantially reduced HDL-C but significantly increased macrophage RCT. Furthermore, probucol significantly enhanced the excretion of HDL-derived cholesterol into feces in both WT and SR-BI knockout mice. Probucol inhibited ABCA1-dependent cholesterol efflux from mouse primary hepatocytes, and this effect was shown to be responsible for the effect of probucol on increasing the fecal excretion of HDL-derived cholesterol in vivo. CONCLUSIONS: We demonstrate that pharmacological inhibition of hepatic ABCA1 activity with probucol reduced HDL-C levels but promoted RCT through diversion of HDL-derived cholesterol from efflux back into plasma instead to excretion in the bile. These results explain the beneficial effects of probucol on atherosclerosis and xanthomas despite its HDL-lowering effects and suggest that inactivation of hepatic ABCA1 leads to increased RCT despite reducing plasma HDL-C levels.