Utility of serum ß2-microglobulin for prediction of kidney outcome among patients with biopsy-proven diabetic nephropathy.

AIM: To examine whether serum ß2-microglobulin (ß2-MG) could improve the prediction performance for kidney failure with replacement therapy (KFRT) among patients with diabetic nephropathy (DN). METHODS: Patients with biopsy-proven DN at Nara Medical University Hospital were included. The exposure of interest was log-transformed serum ß2-MG levels measured at kidney biopsy. The outcome variable was KFRT. Multivariable Cox regression models and competing-risk regression models, with all-cause mortality as a competing event, were performed. Model fit by adding serum ß2-MG levels was calculated using the Akaike information criterion (AIC). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indexes were used to evaluate the improvement of predictive performance for 5-year cumulative incidence of KFRT by serum ß2-MG levels. RESULTS: Among 408 patients, 99 developed KFRT during a median follow-up period of 6.7 years. A higher serum ß2-MG level (1-unit increase in log-transformed serum ß2-MG level) was associated with a higher incidence of KFRT, even after adjustments for previously known clinical and histological risk factors (hazard ratio [95% confidence interval {CI}]: 3.30 [1.57-6.94] and subdistribution hazard ratio [95% CI]: 3.07 [1.55-6.06]). The addition of log-transformed serum ß2-MG level reduced AIC and improved the prediction of KFRT (NRI and IDI: 0.32 [0.09-0.54] and 0.03 [0.01-0.56], respectively). CONCLUSIONS: Among patients with biopsy-proven DN, serum ß2-MG was an independent predictor of KFRT and improved prediction performance. In addition to serum creatinine, serum ß2-MG should probably be measured for DN.

Differential impact of glomerular and tubule-interstitial histological changes on kidney outcome between non-proteinuric and proteinuric diabetic nephropathy.

BACKGROUND: Studies on kidney function and histological findings in diabetic nephropathy (DN) with low urinary protein (UP) are few. We examined the differential impact of histological changes on kidney outcomes between non-proteinuric and proteinuric DN. METHODS: Patients diagnosed with DN by renal biopsy during 1981-2014 were divided into non-proteinuric (UP ≤ 0.5 g/day) and proteinuric (UP > 0.5 g/day) DN. The Cox proportional hazard model was used to examine the association of glomerular lesions (GLs) and interstitial fibrosis and tubular atrophy (IFTA) with end-stage kidney disease (ESKD) development after adjusting for relevant confounders. RESULTS: The non-proteinuric and proteinuric DN groups included 197 and 199 patients, respectively. During the 10.7-year median follow-up period, 16 and 83 patients developed ESKD in the non-proteinuric and proteinuric DN groups, respectively. In the multivariable Cox hazard model, hazard ratios (HRs) [95% confidence intervals (CIs)] of GL and IFTA for ESKD in proteinuric DN were 2.94 [1.67-5.36] and 3.82 [2.06-7.53], respectively. Meanwhile, HRs [95% CIs] of GL and IFTA in non-proteinuric DN were < 0.01 [0-2.48] and 4.98 [1.33-18.0], respectively. IFTA was consistently associated with higher incidences of ESKD regardless of proteinuria levels (P for interaction = 0.49). The prognostic impact of GLs on ESKD was significantly decreased as proteinuria levels decreased (P for interaction < 0.01). CONCLUSIONS: IFTA is consistently a useful predictor of kidney prognosis in both non-proteinuric and proteinuric DN, while GLs are a significant predictor of kidney prognosis only in proteinuric DN.

Kidney function at 3 months after acute kidney injury is an unreliable indicator of subsequent kidney dysfunction: the NARA-AKI Cohort Study.

BACKGROUND: The relationship between kidney function at 3 months after acute kidney injury (AKI) and kidney function prognosis has not been characterized. METHODS: This retrospective cohort study included adults who underwent noncardiac surgery under general anesthesia. Exclusion criteria included obstetric or urological surgery, missing data and preoperative dialysis. Linear mixed-effects models were used to compare estimated glomerular filtration rate (eGFR) slopes in patients with and without AKI. Multivariable Cox proportional hazard models were used to examine the associations of AKI with incident chronic kidney disease (CKD) and decline in eGFR ≥30%. RESULTS: Among 5272 patients, 316 (6.0%) developed AKI. Among 1194 patients with follow-up creatinine values, eGFR was stable or increased in patients with and without AKI at 3 months postoperatively and declined thereafter. eGFR decline after 3 months postoperatively was faster among patients with AKI than among patients without AKI (P = .09). Among 938 patients without CKD-both at baseline and at 3 months postoperatively-226 and 161 developed incident CKD and a decline in eGFR ≥30%, respectively. Despite adjustment for eGFR at 3 months, AKI was associated with incident CKD {hazard ratio [HR] 1.73 [95% confidence interval (CI) 1.06-2.84]} and a decline in eGFR ≥30% [HR 2.41 (95% CI 1.51-3.84)]. CONCLUSIONS: AKI was associated with worse kidney outcomes, regardless of eGFR at 3 months after surgery. Creatinine-based eGFR values at 3 months after AKI might be affected by acute illness-induced loss of muscle mass. Kidney function might be more accurately evaluated much later after surgery or using cystatin C values.

Trace proteinuria detected via dipstick test is associated with kidney function decline and new-onset overt proteinuria: the Japan Specific Health Checkups (J-SHC) Study.

BACKGROUND: Microalbuminuria is associated with mortality, cardiovascular disease, and end-stage kidney disease. The association between trace proteinuria (detected via dipstick test) and kidney outcomes is unclear. METHODS: This nationwide longitudinal study used data from the Japan Specific Health Checkups Study conducted during 2008-2014. The frequency of trace proteinuria (detected via dipstick test) during first two visits was used as an exposure variable (TrUP 0/2, no trace proteinuria; TrUP 1/2, detected once; TrUP 2/2, detected twice), and kidney outcomes were evaluated. The association between the frequency of trace proteinuria and incidence of 1.5-fold increase in serum creatinine levels and overt proteinuria was analyzed using Cox regression analysis. Trajectories of estimated glomerular filtration rate (eGFR) were compared using a mixed-effect model. RESULTS: Among 306,317 participants, 3188 and 17,461 developed a 1.5-fold increase in serum creatinine levels and new-onset overt proteinuria, respectively, during the median follow-up period of 36.2 months. The adjusted hazard ratio (HR) and 95% confidence interval (CI) for 1.5-fold increase in serum creatinine level in the TrUP 1/2 and TrUP 2/2 groups, compared to TrUP 0/2 group, were 1.23 (1.07-1.42) and 1.39 (1.01-1.92), respectively, and the adjusted HR (95% CI) for overt proteinuria were 2.94 (2.83-3.06) and 5.14 (4.80-5.51), respectively. The eGFR decline rates in the TrUP 1/2 and TrUP 2/2 groups were higher than that in the TrUP 0/2 group (p for interaction < 0.001). CONCLUSIONS: Trace proteinuria (detected via dipstick test) was associated with subsequent kidney function decline and overt proteinuria in the general population.

Synergistic effect of proteinuria on dipstick hematuria-related decline in kidney function: The Japan Specific Health Checkups (J-SHC) Study.

BACKGROUND: The effect of isolated hematuria without proteinuria on kidney function decline, and the modification by the severity of proteinuria in general population are not fully elucidated. METHODS: Participants were included in the Japan Specific Health Checkups Study between 2008 and 2014. The exposure of interest was the frequency of dipstick hematuria during the observation. In each proteinuria frequency category (non-, occasional, persistent), hematuria-related decline in the eGFR rate was examined by analysis of covariance (ANCOVA). eGFR decline trajectories were also assessed using mixed-effects models. RESULTS: Among the 552,951 participants, 146,753 (26.5%) had hematuria, and 56,021 (10.1%) and 8,061 (1.5%) had occasional and persistent proteinuria, respectively. During the median follow-up of 3.0 years, annual change in eGFR decline in participants with hematuria was significantly faster than in those without hematuria (mean [95% confidence interval]: - 0.95 [- 0.98 to - 0.92] vs - 0.86 [- 0.87 to - 0.84] mL/min/1.73 m2/year; P < 0.001). In ANCOVA, the hematuria-related annual eGFR decline rate increased as proteinuria frequency categories increased (differences in annual eGFR decline rate between participants with and without hematuria: 0.08 [0.06 to 0.09] in participants with non-proteinuria category, 0.17 [0.15 to 0.18] in occasional proteinuria category, and 0.68 [0.65 to 0.71] mL/min/1.73 m2/year in persistent proteinuria category; P for interaction < 0.001). Similar results were obtained by the linear mixed-effect model. CONCLUSIONS: Proteinuria has a synergistic effect on dipstick hematuria-related decline in kidney function. Among the general population without proteinuria throughout the observational period, the "isolated hematuria"-related eGFR decline was statistically significant but the difference was small.

Renal histological continuum of TAFRO syndrome: A case report and literature review.

TAFRO syndrome is a rare systemic inflammatory disorder that is characterized by thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly. Progressive renal involvement is frequently observed in patients with TAFRO syndrome, and the renal histological findings remain limited. A 52-year-old man with thymoma that was detected by chest computed tomography was admitted to our hospital because of dyspnea and abdominal distension. He had a rapid reappearance of pleural and abdominal effusion following repeated puncture with inflammation and kidney involvement on admission. Renal histology showed glomerular lesions denoting diffuse endocapillary proliferative glomerulonephritis, without any crescentic glomeruli, which was diagnosed as thrombotic microangiopathy (TMA)-like glomerulopathy. Together with histological findings of thymoma and progressively emergent thrombocytopenia, the patient was diagnosed with TAFRO syndrome. Corticosteroid and tocilizumab administration ameliorated the renal insufficiency and his clinical condition relevant to TAFRO syndrome, but there was a rapid concomitant appearance of massive proteinuria. A second renal biopsy revealed membranoproliferative glomerulonephritis (MPGN)-like glomerulopathy with de novo sclerosing and crescentic glomeruli development. Patients with TAFRO syndrome show glomerular lesions that are consistent with TMA- or MPGN-like lesions, but their clinical data are similar between the two glomerulopathies. It remains controversial whether the two are a histopathological continuum or distinct diseases. This case shows that glomerular lesions had TMA-like glomerulopathy in the acute stage of TAFRO syndrome, while the histopathology pattern favors MPGN in the chronic stage, as confirmed by repeated renal biopsies. TAFRO syndrome disease activity may not always correspond to that of glomerulopathy that is associated with TAFRO syndrome.

The association of 5-year therapeutic responsiveness with long-term renal outcome in IgA nephropathy.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis. Since most patients have a relatively benign renal prognosis, long-term follow-up is required. During such a long course of disease, relapse of IgAN is occasionally observed after upper respiratory tract infection or without any trigger. However, little is known about the impact of relapse on long-term renal outcomes. METHODS: In this retrospective cohort study of biopsy-proven primary IgAN, we analyzed the association of 5-year therapeutic responsiveness (relapse) with the subsequent development of end-stage kidney disease (ESKD) using a 5-year landmark analysis (Cox model) and explored predictors of relapse from histological and clinical data at baseline. RESULTS: Among 563 patients from the exploratory cohort, most relapses (13.7%) occurred within 5 years after treatment. Using 5-year landmark analysis, among 470 patients, 79 developed ESKD during a median follow-up period of 155 months. Even after adjustment for clinicopathological relevant confounders, hazard ratios (95% confidence intervals) in the relapse and non-responder groups compared with the remission group were 2.86 (1.41-5.79) and 2.74 (1.48-5.11), respectively. Among 250 patients who achieved remission within 5 years, proteinuria, eGFR, mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, and crescent, but not interstitial fibrosis/tubular atrophy, were independent predictors of 5-year relapse in multivariable logistic regression analysis, CONCLUSIONS: Both relapsers and non-responders had similarly strong association with ESKD in patients with IgAN. We also confirmed the predictors of relapse 5 years after renal biopsy, which may guide the treatment strategies for patients with IgAN who occasionally relapse after remission.

Association of initial prednisolone dose with remission, relapse, and infectious complications in adult-onset minimal change disease.

BACKGROUND: A dose of 0.5-1 mg/kg/day of prednisolone (PSL) is administered for the initial treatment of minimal change disease (MCD). However, little is known about the optimal PSL dose for the initial treatment of MCD. METHODS: We conducted a retrospective multicenter cohort study of treatment-naive adult patients with MCD diagnosed by renal biopsy from 1981 to 2015 in whom PSL monotherapy was performed as the initial treatment. The exposure of interest was an initial median PSL dose of < 0.63 mg/kg/day (Group L) compared to ≥ 0.63 mg/kg/day (Group H). Cumulative remission and relapse after remission were compared between these groups using Cox regression adjusted for baseline characteristics. RESULTS: Ninety-one patients met the inclusion criteria. During a median follow-up of 2.98 years, 87 (95.6%) patients achieved complete remission, and 47.1% relapsed after remission. There was no significant difference in the remission rate between the groups at 4 weeks of follow-up (66.7 vs. 82.6%). The median time to remission in Group L was comparable to that in Group H (17.0 vs. 14.0 days). A multivariable Cox hazard model revealed that the initial PSL dose was not a significant predictor of remission. The cumulative steroid doses at 6 months, 1 year, and 2 years after treatment initiation were significantly lower in Group L than in Group H. CONCLUSION: The initial PSL dose was not associated with time to remission, remission rate, time to relapse, or relapse rate. Therefore, a low initial steroid dose may be sufficient to achieve remission.

sFlt-1 in Chronic Kidney Disease: Friend or Foe?

Placental growth factor (PlGF) and its receptor, fms-like tyrosine kinase-1 (Flt-1), are important regulators involved in angiogenesis, atherogenesis, and inflammation. This review article focuses on the function of PlGF/Flt-1 signaling and its regulation by soluble Flt-1 (sFlt-1) in chronic kidney disease (CKD). Elevation of circulating sFlt-1 and downregulation of sFlt-1 in the vascular endothelium by uremic toxins and oxidative stress both exacerbate heart failure and atherosclerosis. Circulating sFlt-1 is inconsistent with sFlt-1 synthesis, because levels of matrix-bound sFlt-1 are much higher than those of circulating sFlt-1, as verified by a heparin loading test, and are drastically reduced in CKD.

Pre-operative proteinuria and post-operative acute kidney injury in noncardiac surgery: the NARA-Acute Kidney Injury cohort study.

BACKGROUND: Little is known about the association between pre-operative proteinuria and post-operative acute kidney injury (AKI) in noncardiac surgery. METHODS: This is a retrospective cohort study. Adults who underwent noncardiac surgery under general anesthesia from 2007 to 2011 at Nara Medical University Hospital were included. Those with obstetric or urological surgery, missing data for analyses or pre-operative dialysis were excluded. Exposure of interest was pre-operative proteinuria, defined as (+) or more by dipstick test. The outcome variable was post-operative AKI, defined by Kidney Disease: Improving Global Outcomes criteria, within 1 week after surgery. Multivariable logistic regression analyses were performed. RESULTS: Among 5168 subjects, 309 (6.0%) developed AKI. Pre-operative proteinuria was independently associated with post-operative AKI, with an odds ratio (OR) [95% confidence interval (CI)] of 1.80 (1.30-2.51). A sensitivity analysis restricted to elective surgery yielded a similar result. As proteinuria increased, the association with AKI became stronger [OR (95% CI) 1.14 (0.75-1.73), 1.24 (0.79-1.95), 2.75 (1.74-4.35) and 3.95 (1.62-9.62) for urinary protein (+/-), (+), (2+) and (3+), respectively]. Subgroup analyses showed proteinuria was especially associated with post-operative AKI among subjects with renin-angiotensin system inhibitors, other anti-hypertensives, hypoalbuminemia or impaired renal function (P for interaction = 0.05, 0.003, 0.09 or 0.02, respectively). CONCLUSIONS: In noncardiac surgery, pre-operative proteinuria was independently associated with post-operative AKI. Subjects with proteinuria should be managed with caution to avoid AKI peri-operatively.

Value of Placental Growth Factor as a Predictor of Adverse Events During the Acute Phase of Acute Decompensated Heart Failure.

BACKGROUND: Few biomarkers, even B-type natriuretic peptide (BNP), can predict the long-term outcome in patients with acute decompensated heart failure (ADHF) on the first day of admission. Placental growth factor (PlGF), a member of the vascular endothelial growth factor family of cytokines, is a key molecule in cardiorenal syndrome and a predictor of adverse events in chronic kidney disease patients. However, its significance in ADHF patients remains poorly understood. Methods and Results: We studied 408 ADHF patients admitted between April 2011 and December 2016 by measuring their PlGF levels on the first day of admission. Primary endpoints were all-cause and cardiovascular (CV) death. Patients were divided into 2 groups according to PlGF quartiles. Kaplan-Meier analysis revealed that the high PlGF group (quartile 4: ≥12.6 pg/mL) had a worse prognosis than the low PlGF group (quartiles 1-3; <12.6 pg/mL) in terms of all-cause (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.13-2.14; P<0.01) and CV death (HR, 1.68; 95% CI, 1.04-2.66; P<0.05). After adjustment for covariates, PlGF remained an independent predictor of all-cause and CV death. CONCLUSIONS: PlGF on the first day of admission was significantly associated with both all-cause and CV death, suggesting that it provides novel prognostic information in the acute phase of ADHF.

Decline in estimated glomerular filtration rate is associated with risk of end-stage renal disease in type 2 diabetes with macroalbuminuria: an observational study from JDNCS.

BACKGROUND: There is increased interest in surrogate endpoints for clinical trials of chronic kidney disease. METHODS: In this nationwide observational study of 456 patients with type 2 diabetes and clinically suspected diabetic nephropathy followed for a median of 4.2 years, we evaluated the association between estimated glomerular filtration rate (eGFR) and albuminuria at baseline or during follow-up and risk of ESRD. RESULTS: Low eGFR (<60 mL/min/1.73 m2) and macroalbuminuria at enrollment were independently associated with risk of ESRD. In patients with macroalbuminuria, both ≤-50% change and -50 to -30% change in eGFR over 1 and 2 years were predictive of ESRD. The higher cut point (≥50% decline in eGFR) was more strongly predictive but less common. Remission of macroalbuminuria to normo-/microalbuminuria at 1 and 2 years was associated with a lower incidence of ESRD than no remission; however, it was not a determinant for ESRD independently of initial eGFR and initial protein-to-creatinine ratio. CONCLUSION: These results suggest that a ≥30% decline in eGFR over 1 or 2 years adds prognostic information about risk for ESRD in patients with type 2 diabetes and macroalbuminuria, supporting the consideration of percentage decline in eGFR as a surrogate endpoint among macroalbuminuric cases in type 2 diabetes. On the other hand, our study suggests that additional analyses on the relationship between remission of macroalbuminuria and risk of ESRD are needed in type 2 diabetes.

Placental Growth Factor as a Predictor of Cardiovascular Events in Patients with CKD from the NARA-CKD Study.

Placental growth factor (PlGF) contributes to atherogenesis through vascular inflammation and plaque destabilization. High levels of PlGF may be associated with mortality and cardiovascular disease, but the relationship between PlGF level and adverse outcomes in patients with CKD is unclear. We conducted a prospective cohort study of 1351 consecutive participants with CKD enrolled in the Novel Assessment of Risk management for Atherosclerotic diseases in CKD (NARA-CKD) study between April 1, 2004, and December 31, 2011. During a median follow-up of 3 years, 199 participants died and 383 had cardiovascular events, defined as atherosclerotic disease or heart failure requiring hospitalization. In adjusted analyses, mortality and cardiovascular risk increased in each successive quartile of serum PlGF level; hazard ratios (HRs) (95% confidence intervals [95% CIs]) for mortality and cardiovascular risk, respectively, were 1.59 (0.83 to 3.16) and 1.55 (0.92 to 2.66) for the second quartile, 2.97 (1.67 to 5.59) and 3.39 (2.20 to 5.41) for the third quartile, and 3.87 (2.24 to 7.08) and 8.42 (5.54 to 13.3) for the fourth quartile. The composite end point of mortality and cardiovascular events occurred during the study period in 76.4% of patients in both the highest PlGF quartile (≥19.6 pg/ml) and the lowest eGFR tertile (<30 ml/min per 1.73 m(2)). The association between PlGF and mortality or cardiovascular events was not attenuated when participants were stratified by age, sex, traditional risk factors, and eGFR. These data suggest elevated PlGF is an independent risk factor for all-cause mortality and cardiovascular events in patients with CKD.

[Klotho and vascular calcification].

The link between chronic kidney disease(CKD)and cardiovascular diseases has recently been attracting attention as cardiorenal connection. Vascular calcification due to down-regulation of klotho is partly involved in the pathogenesis of cardiorenal connection. Klotho protein which is mainly expressed in the distal convoluted tubule, is directly correlated with renal function. Of note, its expression has already been decreased in patients with estimated glomerula filtration rate(eGFR)of 60~90 mL/min/1.73 m2 compared with those with eGFR of more than 90 mL/min/1.73 m2. In early CKD, compensatory mechanisms mediated by fibroblast growth factor 23(FGF23)maintain phosphaturia at a sufficient level;however, in end-staging kidney disease, impaired compensatory mechanisms by further down-regulation of klotho promotes osteochondrocytic differentiation of vascular smooth muscle cells(VSMCs)through phosphate hoarding and increased transcription factors. On the other hands, Klotho protein expressed in VSMCs, suppresses osteochondrocytic differentiation with inhibition of phosphate uptake. Both renal and vascular Klotho protect VSMCs against vascular calcification.

Prognostic Impact of Placental Growth Factor on Mortality and Cardiovascular Events in Dialysis Patients.

BACKGROUND: Placental growth factor (PlGF), a member of the vascular endothelial growth factor (VEGF) family, has recently emerged as a predictor of survival and cardiovascular risk. Along with others, we have shown an independent association between PlGF and cardiovascular events in CKD patients, but not much is known about patients receiving dialysis. METHODS: We studied 205 dialysis patients undergoing cardiac catheterization at the Nara Medical University between April 1, 2004, and December 31, 2012. Serum levels of PlGF and VEGF were measured with ELISA in all the patients. RESULTS: During a median follow-up of 20 months, 121 participants died from any cause or experienced a cardiovascular event. In the fully adjusted analysis, having an above-median PlGF or VEGF level was associated with a hazards ratio for adverse outcomes of 2.55 (1.72-3.83) and 1.39 (0.95-2.04), respectively. Using a multimarker strategy in a model with age, serum albumin, history of coronary artery disease, brain natriuretic peptide and PlGF, patients with 2, 3 and 4 positive markers had a 3.82-, 5.77- and 6.59-fold higher risk of mortality or a cardiovascular event, respectively, compared to those with no positive markers. The model with PlGF had a significantly higher c-statistic, integrated discrimination improvement index and category-free net reclassification improvement index than the model without PlGF. CONCLUSION: PlGF is independently associated with mortality and cardiovascular events, but the association between VEGF and adverse events was attenuated with covariate adjustment. The addition of PlGF to models with established clinical predictors provides additional useful prognostic information in patients receiving dialysis.

Suppressed soluble Fms-like tyrosine kinase-1 production aggravates atherosclerosis in chronic kidney disease.

Patients with chronic kidney disease (CKD) die of cardiovascular diseases for unknown reasons. Blood vessel formation in plaques and its relationship with plaque stability could be involved with signaling through the Flt-1 receptor and its ligands, vascular endothelial growth factor, and the closely related placental growth factor (PlGF). Flt-1 also exists as a circulating regulatory splice variant short-inhibitory form (sFlt-1) that serves as a decoy receptor, thereby inactivating PlGF. Heparin releases sFlt-1 by displacing the sFlt-1 heparin-binding site from heparin sulfate proteoglycans. Heparin could provide diagnostic inference or could also induce an antiangiogenic state. In the present study, postheparin sFlt-1 levels were lower in CKD patients than in control subjects. More importantly, sFlt-1 levels were inversely related to atherosclerosis in CKD patients, and this correlation was more robust after heparin injection, as verified by subsequent cardiovascular events. Knockout of apolipoprotein E (ApoE) and/or sFlt-1 showed that the absence of sFlt-1 worsened atherogenesis in ApoE-deficient mice. Thus, the relationship between atherosclerosis and PlGF signaling, as regulated by sFlt-1, underscores the underappreciated role of heparin in sFlt-1 release. These clinical and experimental data suggest that novel avenues into CKD-dependent atherosclerosis and its detection are warranted.

Urinary FSP1 is a biomarker of crescentic GN.

Fibroblast-specific protein 1 (FSP1)-expressing cells accumulate in damaged kidneys, but whether urinary FSP1 could serve as a biomarker of active renal injury is unknown. We measured urinary FSP1 in 147 patients with various types of glomerular disease using ELISA. Patients with crescentic GN, with or without antinuclear cytoplasmic antibody-associated GN, exhibited elevated levels of urinary FSP1. This assay had a sensitivity of 91.7% and a specificity of 90.2% for crescentic GN in this sample of patients. Moreover, we found that urinary FSP1 became undetectable after successful treatment, suggesting the possible use of FSP1 levels to monitor disease activity over time. Urinary FSP1 levels correlated positively with the number of FSP1-positive glomerular cells, predominantly podocytes and cellular crescents, the likely source of urinary FSP1. Even in patients without crescent formation, patients with high levels of urinary FSP1 had large numbers of FSP1-positive podocytes. Taken together, these data suggest the potential use of urinary FSP1 to screen for active and ongoing glomerular damage, such as the formation of cellular crescents.

The use of anti-adrenergic agents as a predictor of acute kidney injury and delayed recovery of kidney function: the NARA-AKI cohort study.

Association of preoperative regular use of anti-adrenergic agents with postoperative acute kidney injury (AKI) and with trajectory of kidney function after AKI is still unknown. In a retrospective cohort study, adults undergoing non-cardiac surgery under general anesthesia were included. Obstetric or urological surgery, missing data, or preoperative dialysis was excluded. The exposure of interest was preoperative regular use of anti-adrenergic agents. The outcomes were AKI within 1 week postoperatively and trajectories of kidney function within 2 weeks postoperatively among patients with AKI. Multivariable logistic regression models were used to examine the association of anti-adrenergic agents with AKI. Linear mixed-effects models were used to compare the trajectories of postoperative kidney function after AKI between patients with and without anti-adrenergic agents. Among 5168 patients, 245 had used anti-adrenergic agents. A total of 309 (6.0%) developed AKI, and the use of anti-adrenergic agents was independently associated with postoperative AKI even after adjustment for preoperative and intraoperative potential confounders [odds ratio (95% confidence interval): 1.76 (1.14-2.71)]. The association was similar across preexisting hypertension or cardiovascular disease. Analyses restricted to patients with AKI suggested that the timing and stage of AKI were similar among those with and without anti-adrenergic agents; however, the recovery of kidney function was delayed among those with anti-adrenergic agents (P for interaction = 0.004). The use of anti-adrenergic agents was associated with postoperative AKI and delayed recovery of kidney function after AKI. Temporary withdrawal of anti-adrenergic agents during perioperative periods may contribute to prevent AKI and shorten the duration of AKI.

Association of triglycerides to high-density lipoprotein cholesterol ratio with incident cardiovascular disease but not end-stage kidney disease among patients with biopsy-proven diabetic nephropathy.

Increased triglycerides (TG) and decreased high-density lipoprotein cholesterol (HDL-C) are dyslipidemias characteristic of diabetes. Here, we aimed to examine associations of TG/HDL-C ratio with cardiovascular disease (CVD) and kidney dysfunction among patients with diabetic nephropathy. This retrospective observational study consists of patients with biopsy-proven diabetic nephropathy at Nara Medical University Hospital. Exposure of interest was TG/HDL-C ratio measured at kidney biopsy. Outcome variables were kidney histological findings, incident CVD and end-stage kidney disease (ESKD). Multivariable logistic regression models and Cox proportional hazard models were used to examined these associations. A total of 353 subjects were divided into quartiles based on TG/HDL-C ratio: Quartile 1 (reference), <1.96; Quartile 2, 1.96-3.10; Quartile 3, 3.11-4.55; and Quartile 4, ≥4.56. TG/HDL-C ratio was not a predictor of any histological findings in fully adjusted models. During median follow-up periods of 6.2 and 7.3 years, 152 and 90 subjects developed CVD and ESKD, respectively. Higher TG/HDL-C ratio was independently associated with higher incidences of CVD even after adjustments for potential confounders (hazard ratio [95% confidence interval] for Quartile 3 vs. reference; 1.73 [1.08-2.79] and Quartile 4 vs. reference; 1.86 [1.10-3.17]). Although there was a weak association between TG/HDL-C ratio and ESKD in the univariable model, the association was not significant in fully adjusted models. In conclusion, among patients with biopsy-proven diabetic nephropathy, higher TG/HDL-C ratio was independently associated with higher incidences of CVD but not with kidney outcomes, suggesting different impact of TG/HDL-C ratio on cardiorenal outcomes.