Serum NGAL and Cystatin C Comparison With Urinary Albumin-to-Creatinine Ratio and Inflammatory Biomarkers as Early Predictors of Renal Dysfunction in Patients With Type 2 Diabetes

MYCT1 attenuates renal fibrosis and tubular injury in diabetic kidney disease

Tubulointerstitial abnormalities contribute to the progression of diabetic kidney disease (DKD). However, the underlying mechanism of the pathobiology of tubulointerstitial disease is largely unknown. Here, we showed that MYCT1 expression was downregulated in in vitro and in vivo DKD models. Adeno-associated virus (AAV)-Myct1 significantly attenuated renal dysfunction and tubulointerstitial fibrosis in diabetic db/db mice and downregulated Sp1 transcription and TGF-β1/SMAD3 pathway activation. In human proximal tubular epithelial cells, high glucose-induced high expression of SP1 and TGF-β1/SMAD3 pathway activation as well as overaccumulation of extracellular matrix (ECM) were abrogated by MYCT1 overexpression. Mechanistically, the binding of VDR to the MYCT1 promoter was predicted and confirmed using dual-luciferase reporter and ChIP analysis. VDR transcriptionally upregulates MYCT1. Our data reveal MYCT1 as a new and potential therapeutic target in treating DKD.

Significance of serum miR-29a in the occurrence and progression of diabetic nephropathy: A cross-sectional study

BACKGROUND

Diabetic nephropathy (DN), a common microvascular complication of type 2 diabetes mellitus (T2DM), is an important factor causing chronic kidney disease. However, the relationship between miR-29a and DN remains unknown. Therefore, a cross-sectional study was conducted to identify a potential molecular biomarker for DN prevention and management by detecting the serum miR-29a levels.

METHODS

The serum miR-29a levels were measured in 360 subjects (180 T2DM patients and 180 healthy controls) using quantitative reverse transcription PCR (qRT-PCR), and other conventional indicators were measured and analysed. A binary logistic regression was used to evaluate the DN risk factors; a receiver operating characteristic (ROC) curve was applied to analyse the diagnostic efficacy of miR-29a for DN, and a Spearman's rank correlation analysis was used to evaluate the correlation between serum miR-29a and cystatin C.

RESULTS

The serum miR-29 levels in the T2DM patients were higher than those in the healthy subjects and significantly increased with the progression of DN (p < 0.05). Serum miR-29a and cystatin C are independent predictors of the occurrence of DN. Compared with a single indicator, the combination of serum miR-29a and cystatin C has better DN diagnostic performance. In addition, the serum miR-29a levels were positively correlated with cystatin C in the patients with DN (r = 0.521, p < 0.001).

CONCLUSION

The expression of serum miR-29a was significantly associated with the occurrence and progression of DN and is expected to become a potential biomarker for the diagnosis of DN.

hsa-miR-199b-3p Prevents the Epithelial-Mesenchymal Transition and Dysfunction of the Renal Tubule by Regulating E-cadherin through Targeting KDM6A in Diabetic Nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. The association between epithelial-mesenchymal transition (EMT) and fibrosis is quite ascertained, but its link to eventual tubule dysfunction is missing. Here, we show that human microRNA- (hsa-miR-) 199b-3p protects renal tubules from diabetic-induced injury by repressing KDM6A, a histone lysine demethylase regulating E-cadherin expression. Lower E-cadherin expression is related to a higher level of KDM6A, while E-cadherin is promoted upon treatment with the KDM6A inhibitor GSK-J4 in both high glucose- (HG-) induced HK2 cells and the kidneys from streptozotocin- (STZ-) induced type 1 diabetic mice. However, overexpression or RNA silencing of E-cadherin fails to alter KDM6A expression. We also show that the upregulation of KDM6A is associated with the increased methylation level of the E-cadherin promoter. Then, the target prediction results and a dual-luciferase assay show that hsa-miR-199b-3p is a new miRNA that targets KDM6A. Overexpression of hsa-miR-199b-3p increases E-cadherin expression and prevents EMT through repressing KDM6A expression in HG-induced HK2 cells. In contrast, inhibitor-induced hsa-miR-199b-3p knockdown has opposite effects, as it decreases E-cadherin level and worsens EMT, accompanied by increased levels of KDM6A. Besides, Mir199b-knockout mice without mmu-miR-119b-3p expression exhibit more renal tubule dysfunction and more serious kidney tissue damage upon treatment with STZ. These results demonstrate that hsa-miR-199b-3p improves E-cadherin expression and prevents the progression of DN through targeting KDM6A. miR-199b-3p could be a future biomarker or target for the diagnosis or treatment of DN.

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

Role of urinary podocalyxin in early diagnosis of diabetic nephropathy

Introduction. Podocyte injury has been reported as an early feature of DN therefore, the assessment of podocyte injury can be accomplished by estimation of podocalyxin in urine. This study aimed to estimate the urinary podocalyxin levels and to determine the sensitivity and specificity of this biomarker for early detection of DN.Materials and methods. A total of 90 patients with type 2 diabetes mellitus (T2DM) were included in this cross-sectional study. Sixty of them were without diagnosed DN, and 30 with diagnosed DN. A control group consisted of 30 healthy subjects. All patients with T2DM were divided into three subgroups according to urinary microalbumin/creatinine ratio (UM/CR): normoalbuminuric, microalbuminuric and macroalbuminuric patients. Urine samples, were used for measurement of podocalyxin by ELISA, creatinine and microalbumin. Fasting venous blood samples was collected for biochemical analyses.Results. The levels of urinary podocalyxin (u-PDX) were higher in patients with T2DM compared to control subjects and a statistically significant difference among studied subgroups regarding u-PDX was found (p < 0.05). Levels of u-PDX are increasing gradually with the degree of DN (p < 0.029). u-PDX levels were positively correlated with UM/CR (r = 0.227, p = 0.002). A cut-off level of 43.8 ng/ml u-PDX showed 73.3% sensitivity and 93.3% specificity to detect DN in early stage. A cut-off level of 30 mg/g UM/CR showed 41.5% sensitivity and 90% specificity in predicting DN. u-PDX was elevated in 48,2% of normoalbuminuric patients.Conclusion. Urinary podocalyxin be useful and more sensitive and specific marker in early detection of DN than microalbuminuria.

Effects of thromboxane prostanoid receptor deficiency on diabetic nephropathy induced by high fat diet and streptozotocin in mice

Diabetic nephropathy (DN), one of the main causes of end-stage renal disease, still remains as a challenge of clinical management. This study aimed to determine whether deficiency of the thromboxane (TX) prostanoid receptor (TP), which mediates the contractile activities of all prostanoids, alleviates the development of DN and if so, to examine the underlying mechanism(s). Diabetes was induced by high fat diet and streptozotocin injection in wild-type (WT) mice and those with TP deficiency (TP^-/-). Here we show that WT and TP^-/- mice developed diabetes with a similar blood glucose level; however, signs of renal functional impairments and pathologies occurred to a lesser extent in TP^-/- than in WT mice. Also, the extent of an increase in the expression level of transforming growth factor-β1 (TGF-β1), a common pathological mediator of DN, in diabetic renal cortexes of TP^-/- mice was lower than that of WT counterparts. Moreover, we noted that expression levels of cyclooxygenase (COX)-2 and calcium-dependent phospholipase A₂ (cPLA₂) as well as levels of prostaglandin E₂ and TXA₂ in diabetic renal cortexes were increased as compared to those of non-diabetic conditions. These results thus demonstrate that possibly due to up-regulated cPLA₂ and COX-2 that lead to increased prostanoid syntheses in diabetic renal cortexes, TP^-/- alleviates DN development. In addition, our results suggest that such an effect of TP^-/- might be related to the suppression of TGF-β1 up-regulation that is commonly associated with the disease condition.

Expression and clinical significance of serum cystatin C in patients with hypertension and coronary heart disease

The aim of this study is to explore the potential association between cystatin C (Cys-c) and coronary heart disease (CHD) in hypertensive patients.In this study, circulating levels of Cys-c in 62 essential hypertension (EH) patients, 147 hypertension with coronary heart disease (EH + CHD) patients, and 60 healthy volunteers were investigated using immunoturbidimetry. Then, we analyzed the correlations between Cys-C and other clinical parameters.Serum Cys-C level was significantly higher in the EH and EH + CHD groups than in the control group, and higher in the EH + CHD group than in the EH group. Receiver operating characteristic curve (ROC) analysis showed that the diagnostic value of Cys-C for patients with hypertension combined CHD was 0.871(95% CI: 0.818-0.913). Serum Cys-C level was significantly higher in the double-vessel disease group and multi-vessel disease group than in the single-vessel disease group, and higher in the multi-vessel disease group than in the double-vessel disease group. Urinary albumin and CRP correlated positively with Cys-C, and HDL correlated negatively with Cys-C. Cys-C was an independent risk factor for CHD in hypertensive patients.Our results suggested that circulating Cys-C levels was up-regulated in patients with hypertension and CHD, and had correlation with the severity of coronary artery disease. As one of the important risk factors for CHD, Cys-C can predict the occurrence of CHD in patients with hypertension.

Biological variation in kidney injury and kidney function biomarkers among farmers in Lamphun province, Thailand

Frequent and long-term exposure to pesticides can induce acute kidney injury and subsequent chronic kidney diseases. In this study, we aimed to investigate the correlation between kidney injury, kidney function biomarkers, and pesticide use in farmers from the Pasang district, Lamphun province, Thailand. A cross-sectional study was performed in 59 farmers occupationally exposed to various types of pesticides. The levels of urinary neutrophil gelatinase-associated lipocalin (uNGAL), serum creatinine (sCr), urinary microalbumin-to-creatinine ratio (ACR), serum cystatin C (sCys-C), estimated glomerular filtration rate (eGFR), and exposure intensity index (EII) were evaluated. Spearman's correlation and a linear regression analysis were carried out to investigate the association between age, pesticide use, EII, kidney injury markers, and kidney function biomarkers. The most common pesticide used in this study area was glyphosate, followed by paraquat and iprodione. Urinary NGAL levels showed a significant correlation with sCys-C levels, EII, and eGFR Cr-Cys. In addition, the sCr levels were associated with glyphosate use (B = 0.08) and EII (B = 0.01). In conclusion, occupation exposure to pesticides is likely to be linked to kidney injury and dysfunction. Pesticide mix status, pesticide application method, equipment repair status, and personal protective equipment (PPE) use are all involved in changes in kidney markers.

Albuminuric and non-albuminuric patterns of chronic kidney disease in type 2 diabetes

A growing body of evidence supports a shift in the natural history of chronic kidney disease (CKD) in subjects with diabetes. Specifically, normoalbuminuric chronic kidney disease (NA-CKD), which is characterized by a decline in the glomerular filtration rate in the absence of a preceding or accompanying elevation of albuminuria, has become a widely prevalent variant of renal impairment in diabetes. Diabetic women and nonsmoking individuals with better glycemic control have a better chance of preserving normoalbuminuria, even in the case of declining renal function. The wide use of renin-angiotensin system blockers, advances in antihyperglycemic, antihypertensive, and hypolipidemic therapy, and smoking cessation are suspected to be responsible for an increasing proportion of NA-CKD among diabetic subjects with renal impairment. Significant differences in the sets of risk factors, renal morphology, comorbidity, and outcomes were found between the albuminuric and normoalbuminuric CKD patterns. NA-CKD, even if a more favorable option in terms of the risk of end-stage renal disease, is clearly associated with cardiovascular disease and its risk factors. The presence of NA-CKD in patients with diabetes increases the risk of myocardial infarction, stroke, and cardiovascular death. The study of the molecular pathways, clinical course, and outcomes of NA-CKD in diabetic subjects and the search for more specific diagnostic and treatment options are challenges for future research.

Evaluation of cystatin C and neutrophil gelatinase-associated lipocalin as predictors of mortality in patients undergoing percutaneous mitral valve repair (MitraClip)

BACKGROUND

Compromised renal function is a major risk factor that is strongly associated with poor outcome in patients with mitral regurgitation (MR) and heart failure. Cystatin C, a cysteine protease inhibitor, has been used as a specific and sensitive biomarker of renal function. Neutrophil gelatinase-associated lipocalin (NGAL) is another sensitive biomarker that specifically indicates functional and structural kidney damage. The aim of the present study was to determine the predictive value of serum cystatin C and urinary NGAL as indicators of mortality in patients undergoing percutaneous mitral valve repair (PMVR).

METHODS

A total of 120 consecutive patients (age: 77.3 years [±11.2]) undergoing PMVR using the MitraClip system were included in this study. Venous blood and urinary samples were collected for biomarker analysis prior to PMVR. Physiological parameters, medication use, safety events, and all-cause mortality were assessed 12 months after the procedure.

RESULTS

Twelve months after PMVR, there was a significant reduction in the severity of MR (P < 0.001), and an improvement in the New York Heart Association class (P < 0.01) was documented. Baseline levels of serum cystatin C (nonsurvivors: 2.4 mg/L [interquartile, IQR: 1.7;3.1] vs survivors: 1.7 mg/L [IQR: 1,3;2.1], P < 0.001) and urinary NGAL (nonsurvivors: 242.0 ng/mL [IQR: 154.5;281.5] vs survivors: 132.0 ng/mL [IQR:107.0;177.3], P < 0.001) were significantly higher in patients who died during the 12-month follow-up period.

CONCLUSION

Cystatin C and urinary NGAL were found to be predictors of long-term mortality in high-risk patients undergoing PMVR. Thus, cystatin C and NGAL assessment may be helpful in risk stratification in patients undergoing PMVR.

Glomerular hyperfiltration and β-2 microglobulin as biomarkers of incipient renal dysfunction in cancer survivors

Herein, we aimed to evaluate the occurrence of impaired renal function after cancer treatment with potentially nephrotoxic chemotherapy in children. A cross-sectional study was performed in 41 cancer survivors after chemotherapy with potentially nephrotoxic drugs. 26 (63.4%) children were detected with glomerular hyperfiltration, and urinary levels of β-2 microglobulin (B2MG) were higher than reference range in all patients. Levels of B2MG were positively correlated with plasma creatinine and negatively correlated with glomerular filtration rate. Plasma creatinine, systolic blood pressure and cholesterol were independently associated with B2MG values. The final multivariate model for glomerular hyperfiltration risk included plasma levels of urea and of magnesium. Urinary levels of B2MG and glomerular hyperfiltration may emerge as potential biomarkers of early renal dysfunction in childhood cancer survivors.