Single-cell transcriptomic profiles in the pathophysiology within the microenvironment of early diabetic kidney disease.

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, resulting in a huge socio-economic impact. Kidney is a highly complex organ and the pathogenesis underlying kidney organization involves complex cell-to-cell interaction within the heterogeneous kidney milieu. Advanced single-cell RNA sequencing (scRNA-seq) could reveal the complex architecture and interaction with the microenvironment in early DKD. We used scRNA-seq to investigate early changes in the kidney of db/m mice and db/db mice at the 14th week. Uniform Manifold Approximation and Projection were applied to classify cells into different clusters at a proper resolution. Weighted gene co-expression network analysis was used to identify the key molecules specifically expressed in kidney tubules. Information of cell-cell communication within the kidney was obtained using receptor-ligand pairing resources. In vitro model, human subjects, and co-detection by indexing staining were used to identify the pathophysiologic role of the hub genes in DKD. Among four distinct subsets of the proximal tubule (PT), lower percentages of proliferative PT and PT containing AQP4 expression (PTAQP4+) in db/db mice induced impaired cell repair activity and dysfunction of renin-angiotensin system modulation in early DKD. We found that ferroptosis was involved in DKD progression, and ceruloplasmin acted as a central regulator of the induction of ferroptosis in PTAQP4+. In addition, lower percentages of thick ascending limbs and collecting ducts with impaired metabolism function were also critical pathogenic features in the kidney of db/db mice. Secreted phosphoprotein 1 (SPP1) mediated pathogenic cross-talk in the tubular microenvironment, as validated by a correlation between urinary SPP1/Cr level and tubular injury. Finally, mesangial cell-derived semaphorin 3C (SEMA3C) further promoted endothelium-mesenchymal transition in glomerular endothelial cells through NRP1 and NRP2, and urinary SEMA3C/Cr level was positively correlated with glomerular injury. These data identified the hub genes involved in pathophysiologic changes within the microenvironment of early DKD.

Proximal tubule-derived exosomes contribute to mesangial cell injury in diabetic nephropathy via miR-92a-1-5p transfer.

BACKGROUND: Diabetic nephropathy (DN) is an increasing threat to human health and regarded to be the leading cause of end-stage renal disease worldwide. Exosomes delivery may play a key role in cross-talk among kidney cells and the progression of DN. However, the mechanisms underlying exosomes in DN remain unclear. METHODS: The cross-disciplinary study, including in vivo, in vitro, and human studies was conducted to explore the cross-talk between proximal tubular epithelial cells (PTECs) and mesangial cells (MCs) in DN. We purified exosome from PTECs treated with high glucose and db/db mice and assessed their influences in the pathologic change of MCs and downstream signal pathway. Healthy individuals and type 2 diabetic patients were enrolled to examine the role of exosomes in clinical applications. RESULTS: High glucose stimulated PTECs to secrete exosomal miR-92a-1-5p, which was taken-up by glomerular MCs, inducing myofibroblast transdifferentiation (MFT) in vitro and in vivo. PTEC-released exosomal 92a-1-5p decreased reticulocalbin-3 expression, leading to endoplasmic reticulum (ER) stress by downregulating genes essential for ER homeostasis including calreticulin and mesencephalic astrocyte-derived neurotrophic factor. Treatment with miR-92a-1-5p inhibitor ameliorated kidney damage in db/db mice with DN. Urinary miR-92a-1-5p could predict kidney injury in type 2 diabetic patients. CONCLUSIONS: PTEC-derived exosomal miR-92a-1-5p modulated the kidney microenvironment in vivo and in vitro models, which altered ER stress and MFT in MCs resulting in DN progression. Further blocking miR-92a-1-5p epigenetic regulatory network could be a potential therapeutic strategy to prevent the progression of DN. Video Abstract.

Diabetic nephropathy (DN) has been the leading cause of end-stage renal disease worldwide. Exosomes play a principle role in cross-talk of kidney cells and further affect the onset or progression of DN. This study firstly demonstrated the communication between proximal tubular epithelial cells (PTECs) and mesangial cells (MCs) through exosome transmission. PTEC-released exosomal 92a-1-5p induced endoplasmic reticulum stress and epithelial-mesenchymal transition in MCs through reticulocalbin-3 modulation. Kidney damage was rescued in DN mice after treatment with miR-92a-1-5p inhibitor. Moreover, urinary exosomal miR-92a-1-5p could predict DN progression in type 2 diabetic patients. These findings prove the impact of exosomal miR-92a-1-5p on pathophysiologic mechanisms and its potential use in clinical care and prediction of DN.

N-Octyl Caffeamide, a Caffeic Acid Amide Derivative, Prevents Progression of Diabetes and Hepatic Steatosis in High-Fat Diet Induced Obese Mice.

The underlying pathological mechanisms of diabetes are complicated and varied in diabetic patients, which may lead to the current medications often failing to maintain glycemic control in the long term. Thus, the discovery of diverse new compounds for developing medicines to treat diabetes and its complications are urgently needed. Polyphenols are metabolites of plants and have been employed in the prevention and treatment of a variety of diseases. Caffeic acid phenethyl ester (CAPE) is a category of compounds structurally similar to polyphenols. In this study, we aimed to investigate the antidiabetic activity and potential molecular mechanisms of a novel synthetic CAPE derivative N-octyl caffeamide (36M) using high-fat (HF) diet induced obese mouse models. Our results demonstrate that 36M prevented the progression of diabetes in the HF diet fed obese mice via increasing phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and inhibiting expression of protein tyrosine phosphatase 1B (PTP1B). We also found that 36M could prevent hepatic lipid storage in the HF diet fed mice via inhibition of fatty acid synthase and lipid droplet proteins, including perilipins and Fsp27. In conclusion, 36M is a potential candidate compound that can be developed as AMPK inhibitor and PTP1B inhibitor for treating diabetes and hepatic steatosis.

Investigation of the Relationship between Cardiovascular Biomarkers and Brachial-Ankle Pulse Wave Velocity in Hemodialysis Patients.

Brachial−ankle pulse wave velocity (baPWV) and cardiovascular (CV) biomarkers are correlated with clinical cardiovascular diseases (CVDs) in patients with kidney disease. However, limited studies evaluated the relationship between baPWV and CV biomarkers in hemodialysis patients. This study investigated the relationship between circulating CV biomarkers and baPWV in patients on hemodialysis. Hemodialysis patients were enrolled between August 2016 and January 2017 for the measurement of baPWV, traditional CV biomarkers, including high-sensitivity troponin-T (hsTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), and novel CV biomarkers, including Galectin-3, Cathepsin D, placental growth factor, Endocan-1, and Fetuin-A. The independent association was assessed by multivariate-adjusted linear regression analysis to control for potential confounders. The final analysis included 176 patients (95 men and 81 women) with a mean age of 60 ± 11 y old. After adjusting for age and sex, hsTnT (p < 0.01), NT-proBNP (p = 0.01), Galectin-3 (p = 0.03), and Cathepsin D (p < 0.01) were significantly directly correlated with baPWV. The direct correlation with baPWV existed in multivariable linear regression models with a ß of 0.1 for hsTnT and 0.1 for Cathepsin D. The direct relationship between baPWV and CV biomarkers, particularly with hsTnT and Cathepsin D, may be helpful for risk stratification of hemodialysis patients.

The relationship of indoxyl sulfate and p-cresyl sulfate with target cardiovascular proteins in hemodialysis patients.

Protein-bound uremic toxins (Indoxyl sulfate [IS] and p-cresyl sulfate [PCS]) are both associated with cardiovascular (CV) and all-cause mortality in subjects with chronic kidney disease (CKD). Possible mechanisms have not been elucidated. In hemodialysis patients, we investigated the relationship between the free form of IS and PCS and 181 CV-related proteins. First, IS or PCS concentrations were checked, and high levels were associated with an increased risk of acute coronary syndrome (ACS) in 333 stable HD patients. CV proteins were further quantified by a proximity extension assay. We examined associations between the free form protein-bound uremic toxins and the quantified proteins with correction for multiple testing in the discovery process. In the second step, the independent association was evaluated by multivariable-adjusted models. We rank the CV proteins related to protein-bound uremic toxins by bootstrapped confidence intervals and ascending p-value. Six proteins (signaling lymphocytic activation molecule family member 5, complement component C1q receptor, C-C motif chemokine 15 [CCL15], bleomycin hydrolase, perlecan, and cluster of differentiation 166 antigen) were negatively associated with IS. Fibroblast growth factor 23 [FGF23] was the only CV protein positively associated with IS. Three proteins (complement component C1q receptor, CCL15, and interleukin-1 receptor-like 2) were negatively associated with PCS. Similar findings were obtained after adjusting for classical CV risk factors. However, only higher levels of FGF23 was related to increased risk of ACS. In conclusion, IS and PCS were associated with several CV-related proteins involved in endothelial barrier function, complement system, cell adhesion, phosphate homeostasis, and inflammation. Multiplex proteomics seems to be a promising way to discover novel pathophysiology of the uremic toxin.

Autocrine Exosomal Fibulin-1 as a Target of MiR-1269b Induces Epithelial-Mesenchymal Transition in Proximal Tubule in Diabetic Nephropathy.

Background: Diabetic nephropathy (DN) is an increasing threat to human health and is regarded to be the leading cause of end-stage renal disease worldwide. Exosomes deliver biomolecule massages and may play a key role in cell communication and the progression of DN. Methods: A cross-disciplinary study, including in vivo, in vitro, and human studies, was conducted to explore the cross-talk within proximal tubular epithelial cells (PTECs) in DN. Exosomal protein from PTECs treated with high glucose (HG) was purified and examined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Next-generation sequencing (NGS) was utilized to analyze RNAs extracted from PTECs from a type 2 diabetic patient and a normal individual. HK-2 cells were used to assess exosomal protein and its modulation and biofunction in DN. Normal individuals and type 2 diabetic patients were enrolled, and nondiabetic db/m mice and diabetic db/db mice were used to validate the molecular mechanism of exosomes in DN. Results: HG stimulated PTECs to increase Fibulin-1 (FBLN1) expression, and PTECs secreted FBLN1 through exosome delivery, thereby inducing epithelial-mesenchymal transition (EMT) in PTECs. Transcriptome analysis found that FBLN1 expression was modulated by miR-1269b, which was downregulated by HG in HK-2 cells. While transfection of miR-1269b reversed FBLN1-mediated EMT in PTECs, miR-1269b inhibitor modulated the phenotype of PTECs toward mesenchymal type under normal glucose (NG) condition. Most importantly, urinary FBLN1 and exosomal miR-1269b levels were correlated with the severity of kidney injury in type 2 diabetic patients. Conclusion: This study demonstrated the communication within PTECs through exosome transmission in an autocrine pattern. MiR-1269b-FBLN1 epigenetic regulatory network could be a potential therapeutic strategy to prevent the progression of DN.

Lung Cancer Cell-Derived Secretome Mediates Paraneoplastic Inflammation and Fibrosis in Kidney in Mice.

Kidney failure is a possible but rare complication in lung cancer patients that may be caused by massive tumor lysis or a paraneoplastic effect. Clinical case reports have documented pathological characteristics of paraneoplastic syndrome in glomeruli, but are short of molecular details. When Lewis lung carcinoma 1 (LLC1) cells were implanted in mice lungs to establish lung cancer, renal failure was frequently observed two weeks post orthotopic xenograft. The high urinary albumin-to-creatinine ratio (ACR) was diagnosed as paraneoplastic nephrotic syndrome in those lung cancer mice. Profiling the secretome of the lung cancer cells revealed that the secretory proteins were potentially nephrotoxic. The nephrotoxicity of lung cancer-derived secretory proteins was tested by examining the pathogenic effects of 1 × 106, 2 × 106, and 5 × 106 LLC1 cell xenografts on the pathogenic progression in kidneys. Severe albuminuria was present in the mice that received 5 × 106 LLC1 cells implantation, whereas 106 cell and 2 × 106 cell-implanted mice have slightly increased albuminuria. Pathological examinations revealed that the glomeruli had capillary loop collapse, tumor antigen deposition in glomeruli, and renal intratubular casts. Since IL-6 and MCP-1 are pathologic markers of glomerulopathy, their distributions were examined in the kidneys of the lung cancer mice. Moderate to severe inflammation in the kidneys was correlated with increases in the number of cells implanted in the mice, which was reflected by renal IL-6 and MCP-1 levels, and urine ACR. TGF-ß signaling-engaged renal fibrosis was validated in the lung cancer mice. These results indicated that lung cancer cells could provoke inflammation and activate renal fibrosis.

Association between Circulation Indole-3-Acetic Acid Levels and Stem Cell Factor in Maintenance Hemodialysis Patients: A Cross-Sectional Study.

: Protein-bound uremic toxin is a cardiovascular (CV) risk factor for patients with end-stage renal disease. Indole-3-acetic acid (IAA) was found to be associated with CV disease but the detailed pathophysiology remains unknown. Moreover, mitogen-activated protein kinase (MAPK) signaling cascades play an important role in the pathogenesis of CV disease. Thus, we explored the association between circulating IAA levels and forty MAPK cascade associated proteins in patients undergoing hemodialysis (HD). Circulating total form IAA was quantified by mass spectrometry and forty MAPK cascade associated proteins by a proximity extension assay in 331 prevalent HD patients. Accounting for multiple testing, and in multivariable-adjusted linear regression models, circulating total form IAA levels were positively associated with stem cell factor (ß coefficient 0.13, 95% confidence interval 0.04 to 0.21, p = 0.004). A bioinformatics approach using the search tool for interactions of chemicals (STITCH) tool provided information that IAA may be involved in the regulation of cell proliferation, hematopoietic cells, and the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway. The knowledge gained here can be generalized, thereby impacting the non-traditional CV risk factors in patients with kidney disease. Further in vitro work is necessary to validate the translation of the mechanistic pathways.

Exploring the Benefit of 2-Methylbutyric Acid in Patients Undergoing Hemodialysis Using a Cardiovascular Proteomics Approach.

Short-chain fatty acids (SCFAs) can reduce pro-inflammatory parameters and oxidative stress, providing potential cardiovascular (CV) benefits. Although some evidence links SCFAs with host metabolic health via several biological mechanisms, the role of SCFA on CV disease in patients with kidney disease remains unclear. Herein, we investigate the association between a SCFA, 2-methylbutyric acid, and target CV proteomics to explore the potential pathophysiology of SCFA-related CV benefit in patients with kidney disease. Circulating 2-methylbutyric acid was quantified by high-performance liquid chromatography and 181 CV proteins by a proximity extension assay in 163 patients undergoing hemodialysis (HD). The associations between 2-methylbutyric acid and CV proteins were evaluated using linear regression analysis with age and gender, and multiple testing adjustment. The selected CV protein in the discovery phase was further confirmed in multivariable-adjusted models and evaluated by continuous scale association. The mean value of circulating 2-methylbutyric acid was 0.22 ± 0.02 µM, which was negatively associated with bone morphogenetic protein 6 (BMP-6) according to the false discovery rate (FDR) multiple testing adjustment method. The 2-methylbutyric acid level remained negatively associated with BMP-6 (ß coefficient -1.00, 95% confidence interval -1.45 to -0.55, p < 0.001) after controlling for other CV risk factors in multivariable models. The cubic spline curve demonstrated a linear relationship. In conclusion, circulating 2-methylbutyric acid level was negatively associated with BMP-6, suggesting that this pathway maybe involved in vascular health in patients undergoing HD. However, further in vitro work is still needed to validate the translation of the mechanistic pathways.

Effect of differences in serum creatinine estimation methodologies on estimated glomerular filtration rate.

INTRODUCTION: Serum creatinine is crucial in glomerular filtration rate (GFR) estimation. Various methods of measuring GFR have been developed, which vary in their ability to estimate the prevalence of chronic kidney disease (CKD) and predict consequences associated with CKD. The use of different laboratory devices also results in uncertainty in estimated GFR (eGFR). The purpose of our study was to discuss the effect of differences in laboratory devices on eGFR when performing serum creatinine measurements. METHODS: 163 participants aged 51.22 ± 18.66 years were enrolled during a community health screening programme conducted on 18 June 2011. Samples were sent to four different hospitals using four different devices to check serum creatinine by the Jaffe and enzymatic creatinine methods. RESULTS: Using Roche Cobas Integra 400, Beckman LX20, Hitachi 7180 and Toshiba TBA - c8000, the proportion of the population with eGFR < 60 mL/min/1.73 m2 was 11.04%, 6.75%, 20.25% and 20.86%, respectively. Moreover, 3.68% of the participants had eGFR < 60 mL/min/1.73 m2 in the laboratory when Roche Cobas Integra 400 was used with the enzymatic creatinine method and compensated Jaffe method. CONCLUSION: Although standardisation of serum creatinine measurement has been achieved by using isotope dilution mass spectrometry, differences in measurement devices still cause substantial bias in the overall results. This affects the application of GFR in the estimation of CKD progression and outcomes associated with CKD.

The Interaction of miR-378i-Skp2 Regulates Cell Senescence in Diabetic Nephropathy.

Diabetic nephropathy (DN) is the major cause of end stage renal disease. Proximal tubular epithelial cell (PTEC) injury occurs early in diabetic kidney, and it is correlated with consequent renal failure. Cellular senescence participates in the pathophysiology of DN, but its role remains unclear. We conducted a cross-disciplinary study, including human, in vivo, and in vitro studies, to explore the novel molecular mechanisms of PTEC senescence in DN. We found that HG induced cell senescence in PTECs, supported by enhanced ß-galactosidase staining, p53 and p27 expression, and reduced cyclin E levels. Transcriptome analysis of PTECs from a type 2 diabetic patient and a normal individual using next generation sequencing (NGS) and systematic bioinformatics analyses indicated that miR-378i and its downstream target S-phase kinase protein 2 (Skp2) contribute to HG-induced senescence in PTECs. High glucose (HG) elevated miR-378i expression in PTECs, and miR-378i transfection reduced Skp2 expression. Urinary miR-378i levels were elevated in both db/db mice and type 2 diabetic patients, whereas decreased Skp2 levels were shown in proximal tubule of db/db mice and human DN. Moreover, urinary miR-378i levels were positively correlated with urinary senescence-associated secretory phenotype cytokines and renal function in in vivo and human study. This study demonstrates that the interaction between miR-378i and Skp2 regulates PTEC senescence of DN. miR-378i has the potential to predict renal injury in DN. These findings suggest future applications in both therapy and in predicting renal dysfunction of DN.

The interaction between N-terminal pro-brain natriuretic peptide and fluid status in adverse clinical outcomes of late stages of chronic kidney disease.

INTRODUCTION: Fluid overload is one of the major characteristics and complications in patients with chronic kidney disease (CKD). N-terminal pro-brain natriuretic peptide (NT-proBNP) is related to fluid status and fluid distribution. The aim of this study is to investigate the interaction between NT-proBNP and fluid status in adverse clinical outcomes of late stages of CKD. METHODS: We enrolled 239 patients with CKD stages 4-5 from January 2011 to December 2011 and followed up until June 2017. Fluid status was presented as hydration status (HS) value measured by body composition monitor, while HS>7% was defined as fluid overload. Clinical outcomes included renal outcomes (commencing dialysis and estimated glomerular filtration rate decline>3 ml/min/1.73 m2/year), all-cause mortality and major adverse cardiovascular events (MACEs). RESULTS: During a mean follow-up of 3.3±2.0 years, 129(54.7%) patients commenced dialysis, 88(37.3%) patients presented rapid renal function decline, and 48(20.3%) had MACEs or died. All patients were stratified by HS of 7% and the median of plasma NT-proBNP. The adjusted risks for commencing dialysis was significantly higher in patients with high plasma NT-proBNP and HS>7% compared to those with low plasma NT-proBNP and HS≦7%. There was a significant interaction between plasma NT-proBNP and HS in commencing dialysis (P-interaction = 0.047). Besides, patients with high plasma NT-proBNP and HS>7% had greater risks for MACEs or all-cause mortality than others with either high plasma NT-proBNP or HS>7%. CONCLUSION: NT-proBNP and fluid overload might have a synergistic association of adverse clinical outcomes in patients with late stages of CKD.

Angiopoietin-2, Renal Deterioration, Major Adverse Cardiovascular Events and All-Cause Mortality in Patients with Diabetic Nephropathy.

BACKGROUND/AIMS: Diabetic nephropathy is the leading cause of end-stage renal disease and accounts for 30∼40% of patients requiring maintenance dialysis, thereby increasing the burden on health insurance programs. Diabetic nephropathy is also the strongest predictor of cardiovascular morbidity and mortality. The aim of this study was to examine whether angiopoietin-2 (Angpt2), a modulator of endothelial function, affects the clinical outcomes of diabetic patients. METHODS: This study enrolled 236 patients with diabetes mellitus with estimated glomerular filtration rate (eGFR) < 60ml/min/1.73m2 from January 2006 to December 2011, who were followed until June 2017. Clinical outcomes included renal outcomes (commencing dialysis and rapid decline in renal function (eGFR decline > 3 ml/min per 1.73 m2/year)), major adverse cardiovascular events (MACEs), and all-cause mortality. RESULTS: Over a mean follow-up period of 3.9±2.7 years, 135 (57.2%) patients commenced dialysis, 106 (44.9%) had rapid decline in renal function, and 50 (21.2%) had MACEs or died from all-causes. Log-formed Angpt2 was significantly associated with increased risks of commencing dialysis (HR: 3.91, 95% CI: 1.56-9.76), rapid renal function decline (OR: 6.81, 95% CI: 1.06-43.88), and MACEs or all-cause mortality (HR: 6.34, 95% CI: 1.18-33.97) in the adjusted analysis. Patients in the highest quartile had hazard ratios of 2.90 and 3.11 for commencing dialysis and rapid renal function decline, respectively, compared to those in the lowest quartile after adjustments. Similar significant dose-response results were found in composite outcomes of either MACEs or all-cause mortality. CONCLUSION: Angpt2 is an independent predictor of adverse clinical outcomes in diabetic patients. Further studies are needed to identify the pathogenic role of Angpt2 in renal deterioration and cardiovascular complications of diabetes mellitus.

The interaction between fluid status and angiopoietin-2 in adverse renal outcomes of chronic kidney disease.

BACKGROUND: Fluid overload is not only the characteristic but also an important complication in chronic kidney disease (CKD) patients. Angiopoietin-2 (Angpt2) disturbs endothelium and vessel permeability, which may induce fluid overload. The aim of this study is to examine the interaction between fluid status and Angpt2 in adverse renal outcomes of CKD. METHODS: This cohort study enrolled 290 patients with CKD stages 3-5 from January 2011 to December 2011 and followed up until December 2015. Fluid status was presented as overhydration (OH) value measured by body composition monitor, while OH>1.1L was defined as fluid overload. Renal outcomes were defined as commencing dialysis and rapid renal function decline (the slope of estimated glomerular filtration rate < -5 ml/min/1.73 m2/y). RESULTS: During a mean follow-up of 38.6±18.3 months, 125 (43.1%) patients progressed to commencing dialysis and 99(34.7%) patients presented rapid renal function decline. All patients were stratified by OH of 1.1L and the median of circulating Angpt2. These patients with both OH>1.1L and high circulating Angpt2 were more likely to reach commencing dialysis compared to other groups. The risks for commencing dialysis and rapid renal function decline were significantly higher in patients with OH>1.1L and high circulating Angpt2 level compared to those with OH≦1.1L and low circulating Angpt2 (2.14, 1.21-3.78, P = 0.009; 4.96, 1.45-16.97, P = 0.01). There was a significant interaction between OH level and circulating Angpt2 in entering dialysis (P-interaction = 0.02). CONCLUSIONS: Fluid overload and Angpt2 might have a synergistic effect on adverse renal outcomes in CKD patients.

Angiopoietin-2, Angiopoietin-1 and subclinical cardiovascular disease in Chronic Kidney Disease.

Angiopoietins (Angpt) and vascular endothelial growth factor (VEGF) have been associated with cardiovascular disease. The study enrolled 270 pre-dialysis stage 3-5 CKD patients to assess the link between circulating Angpt2, Angpt1 and VEGF-A and subclinical measures of cardiovascular structure and function. Serum markers of angiogenesis were measured using commercial enzyme-linked immunosorbent assays. Cardiac structure and function were examined by echocardiography. Brachial-ankle pulse wave velocity (baPWV) was measured by the ankle-brachial index. The adjusted mean of left ventricular mass index (LVMI) was 2.05 in patients of Angpt2 quartile 4 and 1.99 in those of Angpt2 quartile 1 (P = 0.04). Angpt2 was significantly associated with LV hypertrophy (LVH) (Angpt2 quartile 4 compared with Angpt2 quartile 1: adjusted OR: 2.68, 95% CI: 1.15-6.20). Angpt1 was negatively correlated with left atrial diameter (adjusted mean of LAD: 3.59 in Angpt1 quartile 4, 3.92 in Angpt1 quartile 1, P = 0.03). A positive and significant correlation was found between Angpt2 level and baPWV in spearman's correlation, but not in adjusted model. In conclusion, high Angpt2 and low Angpt1 levels were positively associated with abnormal cardiac structure in stages 3-5 CKD patients, which is compatible with the viewpoint that angiopoietins participates in cardiovascular burdens.

Interankle systolic blood pressure difference and renal outcomes in patients with chronic kidney disease.

AIM: Interankle blood pressure (BP) difference has been associated with peripheral artery disease and adverse cardiovascular outcomes. However, the relationship between interankle BP difference and renal outcomes in chronic kidney disease (CKD) has never been evaluated. The purpose of this study was to determine whether interankle BP difference is associated with the rate of renal function decline and progression to renal end points in patients with stage 3-5 CKD. METHODS: We enrolled 144 patients with CKD from one regional hospital. The BP in four limbs was simultaneously measured using an ABI-form device. The decline in renal function was evaluated using an estimated glomerular filtration rate (eGFR) slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min per 1.73 m(2) per year. The renal end points were defined as ≥ 25% decline in eGFR or commencement of dialysis during the follow-up period. RESULTS: During a mean follow-up period of 3.1 years, 90 patients (62.5%) reached renal end points. Multivariate analysis showed that an increased interankle systolic BP difference (per 5 mmHg) was associated with a worse eGFR slope (regression ß, -0.292; 95% confidence interval [CI], -0.482 to -0.102; P = 0.003), rapid renal progression (odds ratio, 1.189; 95% CI, 1.015-1.394; P = 0.032), and an increased risk of progression to renal end points (hazard ratio, 1.126; 95% CI, 1.052-1.204, P = 0.001). CONCLUSION: Interankle systolic BP difference was associated with rapid renal progression and progression to renal end points in patients with stage 3-5 CKD in our study.

Angiopoietin-2 as a Prognostic Biomarker of Major Adverse Cardiovascular Events and All-Cause Mortality in Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) patients have higher prevalence of major adverse cardiovascular events (MACE) and all-cause mortality. Endothelial damage and dysfunction have been regarded as early portents of MACE in CKD patients. Angiopoietin-2 (Ang-2) impairs endothelial function and promotes aberrant neovascularization. The aim of the study was to assess the relationship between circulating Ang-2 and MACE or all-cause mortality in a CKD cohort. METHODS: A total of 621 pre-dialysis stage 3-5 CKD patients were enrolled from January 2006 to December 2011 and were followed up till October 2014. Plasma Ang-2 was measured in duplicate using commercial enzyme-linked immunosorbent assays (ELISA). Clinical outcomes included MACE or all-cause mortality. RESULTS: Of all patients, 122 (19.8%) reached MACE or all-cause mortality. Seventy-two had MACE, 79 died, and 29 had both MACE and all-cause mortality during the follow-up period of 41.5±28.3 months. Ang-2 quintile was divided at 1405.0, 1730.0, 2160.9, and 2829.9 pg/ml. The adjusted HR of MACE or all-cause mortality for every single higher log Ang-2 was 5.69 (95% CI: 2.00-16.20, P = 0.001). The adjusted HR of MACE or all-cause mortality was 2.48 (95% CI: 1.25-4.90) for patients of quintile 5 compared with those of quintile 1. A longitudinal association between MACE or all-cause mortality and stepwise increases in Ang-2 levels was found (P-trend = 0.008). CONCLUSIONS: Ang-2 is an independent predictor of MACE or all-cause mortality in CKD patients. Additional study is necessary in order to explore the mechanism of the association of Ang-2 with adverse outcomes in patients with CKD.

Urinary neutrophil gelatinase-associated lipocalin and clinical outcomes in chronic kidney disease patients.

BACKGROUND: Tubulointerstitial damage is a final common pathway of most renal diseases. Whether urinary neutrophil gelatinase-associated lipocalin (uNGAL), a biomarker for renal tubular damage, is of prognostic value for clinical outcomes in chronic kidney disease (CKD) patients has not been well investigated. METHODS: The uNGAL and proteinuria levels were measured among a cohort of 473 advanced CKD patients of various etiologies recruited during 2002-2009. RESULTS: The estimated glomerular filtration rate (eGFR) was 32.3±22.0 mL/min/1.73 m2 with a urine protein-to-creatinine ratio (UPCR) 680 (255-1248) mg/g and 132 (27.9%) participants had diabetes. The baseline uNGAL level was significantly associated with male gender, eGFR, UPCR, and hemoglobin. The hazard ratio (HR) of the highest uNGAL tertile for end-stage renal disease (ESRD) was 3.44 (95% CI 1.47-8.06, p=0.004). With the adjustment of urine creatinine and urine protein, HR of the highest urine NGAL-to-creatinine ratio (UNCR) tertile and the highest urine NGAL-to-protein ratio (UNPR) tertile was 3.06 (95% CI 1.19-7.90, p=0.02) and 2.10 (95% CI 1.13-3.89, p=0.02), respectively. UNPR increased the prediction of survival model for ESRD. HR of the highest UNCR tertile and UNPR tertile for cardiovascular (CV) events was 2.21 (95% CI 0.81-5.98, p=0.08) and 2.79 (95% CI 1.25-6.26, p=0.01), respectively. None of these were associated with all-cause mortality. CONCLUSIONS: Elevated uNGAL in CKD patients is associated with risks for ESRD and probably CV events. UNPR could improve the prediction for ESRD.

Association of angiopoietin-2 with renal outcome in chronic kidney disease.

BACKGROUND: The pathophysiological mechanisms of renal function progression in chronic kidney disease (CKD) have still not been completely explored. In addition to well-known traditional risk factors, non-traditional risk factors, such as endothelial dysfunction, have gradually attracted physicians' attention. Angiopoietin-2 (Ang-2) impairs endothelial function through preventing angiopoietin-1 from binding to Tie2 receptor. Whether Ang-2 is associated with renal function progression in CKD is unknown. METHODS: This study enrolled 621 patients with stages 3-5 CKD to assess the association of circulating Ang-2 with commencing dialysis, doubling creatinine and rapid decline in renal function (the slope of estimated glomerular filtration rate (eGFR) greater than 5 ml/min per 1.73 m2/y) over follow-up of more than 3 years. RESULTS: Of all patients, 224 patients (36.1%) progressed to commencing dialysis and 165 (26.6%) reached doubling creatinine. 85 subjects (13.9%) had rapid decline in renal function. Ang-2 quartile was divided at 1494.1, 1948.8, and 2593.1 pg/ml. The adjusted HR of composite outcomes, either commencing dialysis or doubling creatinine was 1.53 (95% CI: 1.06-2.23) for subjects of quartile 4 compared with those of quartile 1. The adjusted OR for rapid decline in renal function was 2.96 (95% CI: 1.13-7.76) for subjects of quartile 4 compared with those of quartile 1. The linear mixed-effects model shows a more rapid decrease in eGFR over time in patients with quartile 3 or more of Ang-2 than those with the lowest quartile of Ang-2. CONCLUSIONS: Ang-2 is an independent predictor of adverse renal outcome in CKD. Further study is needed to identify the pathogenic role of Ang-2 in CKD progression.

Urinary neutrophil gelatinase-associated lipocalin levels predict cisplatin-induced acute kidney injury better than albuminuria or urinary cystatin C levels.

Cisplatin-induced acute kidney injury (AKI) is a major concern among clinicians in prescribing cisplatin-based chemotherapy. This study evaluated and compared the ability of urinary biomarkers, including urinary neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, and the urinary albumin to creatinine ratio (ACR) to predict cisplatin-induced AKI. Thirty-three cancer patients receiving cisplatin-based chemotherapy were prospectively studied, including 10 (30%) who developed AKI (the study group). Changes of urinary biomarkers were compared at 4 hours, 8 hours, and 12 hours, and 1 day, 2 days, 3 days, and 4 days after cisplatin intravenous infusions (75mg/m(2)) versus the baseline. There was a significant increase in urinary NGAL levels from 12 hours to 4 days (p<0.05) compared to baseline after cisplatin infusion in the AKI group. The magnitude of these changes over time differed significantly by group (p<0.001). The area under the receiver operating curve describing the relationship between urinary NGAL levels and AKI within 12 hours was 0.865 (95% confidence interval=0.691-1.000). Urinary NGAL levels independently predicted AKI 12 hours after cisplatin (p=0.045) after adjustments for age, gender, body mass index, baseline serum creatinine, and urinary total protein. Urinary NGAL levels may be an early biomarker of AKI in patients receiving cisplatin-based treatment.