Urinary Biomarkers in the Assessment of Early Diabetic Nephropathy

The unique association between the level of plateletcrit and the prevalence of diabetic kidney disease: a cross-sectional study

Objective

The activation of platelets in individuals with type 2 diabetes mellitus (T2DM) triggers inflammation and hemodynamic abnormalities, contributing to the development of diabetic kidney disease (DKD). Despite this, research into the relationship between plateletcrit (PCT) levels and DKD is sparse, with inconsistent conclusions drawn regarding the connection between various platelet parameters and DKD. This highlights the necessity for comprehensive, large-scale population studies. Therefore, our objective is to explore the association between PCT levels and various platelet parameters in relation to DKD.

Methods

In this cross-sectional study, hematological parameter data were collected from a cohort of 4,302 hospitalized Chinese patients. We analyzed the relationships between PCT, platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR), and DKD, along with the urinary albumin-to-creatinine ratio (UACR), and estimated glomerular filtration rate (eGFR). Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic potential of these parameters.

Results

DKD patients exhibited significantly higher PCT levels compared to those without DKD. Multivariate regression analysis identified elevated PCT and PLT levels as potential independent risk factors for both DKD and UACR, while lower MPV levels might serve as independent protective factors for eGFR. The areas under the ROC curve for PCT in relation to DKD and UACR (≥30 mg/g) were 0.523 and 0.526, respectively. The area under the ROC curve for PLT in relation to UACR (≥30 mg/g) was 0.523.

Conclusion

PCT demonstrates a weak diagnostic value for T2DM patients at risk of developing DKD and experiencing proteinuria, and PLT shows a similarly modest diagnostic utility for detecting proteinuria. These insights contribute to a deeper understanding of the complex dynamics involved in DKD. Additionally, incorporating these markers into routine clinical assessments could enhance risk stratification, facilitating early interventions and personalized management strategies.

Urinary mitochondrial DNA may be useful in diagnosing early diabetic nephropathy

The present study aimed to determine whether urinary mitochondrial (mt)DNA could be combined as a non-invasive biomarker with other clinical findings of kidney injury to help diagnose early diabetic nephropathy (DN). A total of 165 patients with type 2 diabetes mellitus (T2DM) were enrolled in the present study and the mtDNA levels in urine were measured using quantitative PCR. The diagnostic value of urinary mtDNA levels in patients with T2DM was compared using estimated glomerular filtration rate (eGFR) or albumin-to-creatinine ratio staging. Spearman correlation analysis was used to analyze the correlation between urinary mtDNA and other clinical findings. Correlation factors for early DN were assessed using univariate logistic regression analysis. Urinary leukocyte and glucose levels do not interfere with urinary mtDNA levels. In patients with T2DM, the level of urinary mtDNA increases in the early stages of kidney injury and further increases with the severity of kidney injury. Urinary mtDNA levels in patients with eGFR 60-90 ml/min/1.73 m2 were higher than that in patients with eGFR >90 ml/min/1.73 m2. The levels of urinary mt89DNA and mt349DNA were negatively correlated with the eGFR level (ρ=-0.437; P<0.001; ρ=-0.390; P<0.001) and positively correlated with the level of cystatin C (ρ=0.177; P=0.025; ρ=0.144; P=0.070). Urinary mtDNA is positively correlated with early DN occurrence [odds ratio (OR), 1.330; 95% confidence interval (CI), 1.175-1.507; P<0.001; OR, 1.328; 95% CI, 1.156-1.525; P<0.001]. In conclusion, urinary mtDNA combined with other clinical indicators of kidney injury may help the diagnosis of early DN.

Evaluation of urinary haptoglobin level as a biomarker of diabetic nephropathy in children with type 1 diabetes

BACKGROUND

Type 1 diabetes mellitus (T1DM) is a common endocrine disease in children. Early recognition of complications of T1DM is important for preventing long-term morbidity and mortality. We aimed to investigate whether urinary haptoglobin level is a biomarker of diabetic nephropathy in children with T1DM.

METHODS

Ninety T1DM patients, aged between 2-18 years, and 60 healthy age-matched children were included in the study. Glycosylated hemoglobin (HbA1c), spot urine creatinine, microalbumin, protein and haptoglobin levels of all cases were measured and compared. Correlations between HbA1c level, duration of diabetes, spot urine microalbumin/creatinine (uACR), protein/creatinine (uPCR), and haptoglobin/creatinine (uHCR) ratios in the T1DM group were evaluated.

RESULTS

T1DM and control groups were homogeneous in terms of age, sex, and anthropometric measurements. uACR was higher in the T1DM group than in the control group (14 mg/g vs. 6 mg/g) while uHCR was not elevated in T1DM patients. Nevertheless, uHCR was higher in the microalbuminuria group when compared to the normoalbuminuria group. In the T1DM group, moderate positive correlations between uPCR with uACR and uHCR, and weak correlation between uACR and uHCR were found (r = 0.60, p < 0.001; r = 0.55, p < 0.001; r = 0.24, p = 0.03, respectively). No significant relationship was found between diabetes duration, HbA1c levels and uACR, uPCR, and uHCR.

CONCLUSIONS

Although uHCR in the T1DM group was similar to the control group, uHCR was higher in the microalbuminuria group than in the normoalbuminuria group. These results show that the uHg level could be a biomarker of diabetic nephropathy, but not earlier than albuminuria in the disease course. A higher resolution version of the Graphical abstract is available as Supplementary information.

Bioinformatics led discovery of biomarkers related to immune infiltration in diabetes nephropathy

BACKGROUND

The leading cause of end-stage renal disease is diabetic nephropathy (DN). A key factor in DN is immune cell infiltration (ICI). It has been shown that immune-related genes play a significant role in inflammation and immune cell recruitment. However, neither the underlying mechanisms nor immune-related biomarkers have been identified in DNs. Using bioinformatics, this study investigated biomarkers associated with immunity in DN.

METHODS

Using bioinformatic methods, this study aimed to identify biomarkers and immune infiltration associated with DN. Gene expression profiles (GSE30528, GSE47183, and GSE104948) were selected from the Gene Expression Omnibus database. First, we identified 23 differentially expressed immune-related genes and 7 signature genes, LYZ, CCL5, ALB, IGF1, CXCL2, NR4A2, and RBP4. Subsequently, protein-protein interaction networks were created, and functional enrichment analysis and genome enrichment analysis were performed using the gene ontology and Kyoto Encyclopedia of Genes and Genome databases. In the R software, the ConsensusClusterPlus package identified 2 different immune modes (cluster A and cluster B) following the consistent clustering method. The infiltration of immune cells between the 2 clusters was analyzed by applying the CIBERSORT method. And preliminarily verified the characteristic genes through in vitro experiments.

RESULTS

In this study, the samples of diabetes nephropathy were classified based on immune related genes, and the Hub genes LYZ, CCL5, ALB, IGF1, CXCL2, NR4A2 and RBP4 related to immune infiltration of diabetes nephropathy were obtained through the analysis of gene expression differences between different subtypes.

CONCLUSIONS

This study was based on bioinformatics technology to analyze the biomarkers of immune related genes in diabetes nephropathy. To analyze the pathogenesis of diabetes nephropathy at the RNA level, and ultimately provide guidance for disease diagnosis, treatment, and prognosis.

Role of neutrophil-lymphocyte ratio as a prognostic marker for type 2 diabetic nephropathy among Indians

Diabetic nephropathy/diabetic kidney disease (DKD) is one of the leading causes of renal failure. Early identification of the development or progression of diabetic nephropathy using appropriate screening and diagnostic tools is very important in order to provide timely and proper management. Inflammation plays a crucial role in development and progression of diabetic nephropathy. The aim of this study was to evaluate the relationship of inflammatory markers (neutrophil-to-lymphocyte ratio-NLR) as an early indicator to prevent the progression of diabetic kidney disease. A total of 158 patients with type 2 diabetes mellitus were distributed into three groups according urinary albumin-to-creatinine ratio. Levels of inflammatory markers neutrophil-to-lymphocyte ratio was recorded and compared among the three groups. Significant differences were detected between the groups in terms of neutrophil-to-lymphocyte ratio (p = 0.000).Characteristic curve analysis of inflammatory markers and microalbuminuria prediction demonstrated an area under curve (AUC) of 0.869 for neutrophil-to-lymphocyte ratio (p = 0.000). A NLR cut-off point of 2.2 has 72.3 % sensitivity and 78.1 % specificity, which suggested sufficient accuracy. Increased neutrophil-to-lymphocyte ratio was significantly correlated with diabetic nephropathy progression and increased neutrophil-to-lymphocyte ratio can be considered as an early indicator and a prognostic risk marker of diabetic nephropathy.

Diagnostic efficacy of cystatin-c in association with different ACE genes predicting renal insufficiency in T2DM

Diabetic nephropathy (DN) seems to be the major cause of chronic kidney disease that may finally lead to End Stage Renal Disease. So, renal function assessment in type 2 diabetes mellitus (T2DM) individuals is very important. Clearly, DN pathogenesis is multifactorial and different proteins, genes and environmental factors can contribute to the onset of the disease. We assessed sensitive and specific biomarkers (in blood and urine) which can predict kidney disease susceptibility among T2DM patients. Serum cystatin-c (cyst-c) in blood and urinary hemeoxygenase (HO-1) in addition to ACE I/D polymorphism and ACE G2350A genotypes. Hundred and eight T2DM patients and 85 controls were enrolled. Serum cystatin-c and urinary (HO-1) were tested by ELISA. Genetic determination of both ACE I/D polymorphism and ACE G2350A genotypes was performed by PCR for all participants. Significant rise in serum cystatin-c and urinary HO-1 levels were shown in diabetic groups compared with control group. Moreover, GG genotype of ACE G2350A gene in diabetic group was associated with rise in serum cystatin-c and urinary HO-1 compared with control group. Mutant AA genotype demonstrated increase in urinary HO-1. DD polymorphism was associated with rise in serum creatinine and cyst-c in diabetic group. Positive correlation was seen between duration of diabetes and serum cyst-c and between serum glucose and urinary (HO-1) in diabetic group. The results from this study indicated an association of serum cystatin-c with GG genotype of ACE G2350A in conjugation with DD polymorphism of ACE I/D which could be an early predictor of tubular injury in T2DM diabetic patients.

Identification of key immune-related genes and immune infiltration in diabetic nephropathy based on machine learning algorithms

BACKGROUND

Diabetic nephropathy (DN) is a complication of diabetes. This study aimed to identify potential diagnostic markers of DN and explore the significance of immune cell infiltration in this pathology.

METHODS

The GSE30528, GSE96804, and GSE1009 datasets were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified by merging the GSE30528 and GSE96804 datasets. Enrichment analyses of the DEGs were performed. A LASSO regression model, support vector machine recursive feature elimination analysis and random forest analysis methods were performed to identify candidate biomarkers. The CIBERSORT algorithm was utilised to compare immune infiltration between DN and normal controls.

RESULTS

In total, 115 DEGs were obtained. The enrichment analysis showed that the DEGs were prominent in immune and inflammatory responses. The DEGs were closely related to kidney disease, urinary system disease, kidney cancer etc. CXCR2, DUSP1, and LPL were recognised as diagnostic markers of DN. The immune cell infiltration analysis indicated that DN patients contained a higher ratio of memory B cells, gamma delta T cells, M1 macrophages, M2 macrophages etc. cells than normal people.

CONCLUSION

Immune cell infiltration is important for the occurrence of DN. CXCR2, DUSP1, and LPL may become novel diagnostic markers of DN.

Risk Factors of Microalbuminuria among Patients with Type 2 Diabetes Mellitus in Korea: A Cross-Sectional Study Based on 2019-2020 Korea National Health and Nutrition Examination Survey Data

Diabetes mellitus is a chronic disease with high economic and social burdens. This study aimed to determine the risk factors of microalbuminuria among patients with type 2 diabetes mellitus. Microalbuminuria is predictive of early-stage renal complications and subsequent progression to renal dysfunction. We collected data on type 2 diabetes patients who participated in the 2019-2020 Korea National Health and Nutrition Examination Survey. The risk factors for microalbuminuria among patients with type 2 diabetes were analyzed using logistic regression. As a result, the odds ratios were 1.036 (95% confidence interval (CI) = 1.019-1.053, p < 0.001) for systolic blood pressure, 0.966 (95% CI = 0.941-0.989, p = 0.007) for high-density lipoprotein cholesterol level, 1.008 (95% CI = 1.002-1.014, p = 0.015) for fasting blood sugar level, and 0.855 (95% CI = 0.729-0.998, p = 0.043) for hemoglobin level. A significant strength of this study is the identification of low hemoglobin level (i.e., anemia) as a risk factor for microalbuminuria in patients with type 2 diabetes. This finding implies that the early detection and management of microalbuminuria can prevent the development of diabetic nephropathy.

Urinary nephrin linked nephropathy in type-2 diabetes mellitus

Diabetic nephropathy is a one of the risk factor for end stage renal disease in patients with type 2 diabetes mellitus. Urinary micr oalbumin currently marker using for diagnosis of nephropathy in type 2 diabetes mellitus due to its larger variability and less specificity. Urinary nephrin is podocyte protein can be act as a early predictable and prognostic marker than micro albumin for nephropathy in type 2 diabetes mellitus. This case-control prospective observational study included 60 type 2 diabetes mellitus and 30 controls after applying criteria. Basic biochemical, clinical and experimental data were measured and recorded. There was a significantly elevated level of urinary nephrin in type 2 diabetes mellitus patients when compared to controls. The urinary nephrin significantly elevated in normo albuminuria group only when compared to urinary ACR and it is positive association with kidney damage. This study concluded significantly elevated levels of urinary nephrin might be used for early diagnosis and prognostic marker for nephropathy in type 2 diabetes mellitus.

Review of potential biomarkers of inflammation and kidney injury in diabetic kidney disease

Diabetic kidney disease is expected to increase rapidly over the coming decades with rising prevalence of diabetes worldwide. Current measures of kidney function based on albuminuria and estimated glomerular filtration rate do not accurately stratify and predict individuals at risk of declining kidney function in diabetes. As a result, recent attention has turned towards identifying and assessing the utility of biomarkers in diabetic kidney disease. This review explores the current literature on biomarkers of inflammation and kidney injury focussing on studies of single or multiple biomarkers between January 2014 and February 2020. Multiple serum and urine biomarkers of inflammation and kidney injury have demonstrated significant association with the development and progression of diabetic kidney disease. Of the inflammatory biomarkers, tumour necrosis factor receptor-1 and -2 were frequently studied and appear to hold most promise as markers of diabetic kidney disease. With regards to kidney injury biomarkers, studies have largely targeted markers of tubular injury of which kidney injury molecule-1, beta-2-microglobulin and neutrophil gelatinase-associated lipocalin emerged as potential candidates. Finally, the use of a small panel of selective biomarkers appears to perform just as well as a panel of multiple biomarkers for predicting kidney function decline.

Preference between serum homocysteine and urinary periostin as early predictive biomarkers of renal dysfunction among uncontrolled diabetics

OBJECTIVES

Type 2 diabetes mellitus (T2DM) represents a serious public health problem. Environmental toxins, other than infectious agents or exposures can stimulate immune responses which are associated with the occurrence of T2DM. Diabetic nephropathy (DN) is a serious complication of diabetes that leads to changes in the structure and function of the kidneys. The study aimed to detect diagnostic biomarkers for (DN), at an early stage, to prevent disease progression in these patients and improve their outcomes.

METHODS

This study was performed on 102 T2DM patients and 80 normal controls. Blood glucose, HbA_1c, serum homocysteine (Hcy) and urinary periostin were assessed. Patients were divided into: controlled (n=46) (HbA_1c <6.5%) and uncontrolled diabetics (n=56) (HbA_1c >6.5%).

RESULTS

The study results revealed a significant rise in blood glucose and HbA_1c as well as serum Hcy levels in diabetic groups compared to controls. Also, urinary periostin exhibited significant elevation in diabetic groups. Serum glucose, HbA_1c and serum Hcy revealed a highly significant difference between diabetic subgroups and control groups, while urinary periostin demonstrated a non-significant difference. Only, urinary periostin showed a significant increase in uncontrolled diabetics.

CONCLUSIONS

The highest levels of serum Hcy and urinary periostin were recorded only in the uncontrolled diabetics. Urinary periostin was demonstrated as a more preferable biomarker being a non-invasive sample for predicting renal insult in diabetic subjects. This biomarker could be performed regularly for early detection of DN. Also, it could be added to the periodic medical examinations of workers occupationally exposed to workplace pollutants inducing diabetes.

Etlingera elatior Flower Aqueous Extract Protects against Oxidative Stress-Induced Nephropathy in a Rat Model of Type 2 Diabetes

Diabetes mellitus (DM) is a known systemic disease with increasing global prevalence and multi-organ complications including diabetic nephropathy (DN). The trend of using medicinal plants in the management of DM is increasing exponentially. Etlingera elatior is a medicinal plant that contains chemicals and antioxidants that delay the oxidation process. However, available data focusing on its use on DN are inconsistent and scarce. This study aims to investigate the antidiabetic and nephroprotective effects of E. elatior flower aqueous extract (EEAE) in a type 2 DM rat (T2DR) model. The T2DR model was developed using a combination of a high-fat diet (HFD) and a low dose of streptozotocin (STZ) at 35 mg/kg. Thirty-two Sprague Dawley male rats were randomly divided into four groups (n = 8): (1) control (normal rat), (2) T2DR (untreated-type 2 diabetic rat), (3) Met (250 mg/kg metformin-treated T2DR), and (4) EEAE (1000 mg/kg EEAE-treated T2DR). All treatments were administered orally for 6 weeks. EEAE significantly reduced fasting blood glucose (FBG), microalbuminuria, serum creatinine, and serum blood urea nitrogen. EEAE also reduced malondialdehyde (MDA) and enhanced the levels of antioxidant markers—superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and total antioxidant capacity (T-AOC). The inflammatory marker (interleukin (IL)-6) and fibrosis markers (transforming growth factor-beta (TGF-β), and connective tissue growth factor (CTGF)) were significantly decreased in the EEAE-treated group. The T2DR group developed DN, which was characterized by segmental sclerosis of the glomeruli associated with focal tubular atrophy and interstitial fibrosis. Interestingly, the histology of kidney tissue in the EEAE group was preserved. This effect was similar to that of the control drug metformin. In summary, the antidiabetic and nephroprotective effects might be related to the antioxidant properties and anti-inflammatory effects of the EEAE. The antidiabetic activity could be due to the presence of the active compound cyanidin-3-O-glycosides, which is an anthocyanin antioxidant, that is present in the EEAE. E. elatior has the potential to be developed as a natural source of antioxidants that can be used for the prevention or even the treatment of DM. These findings could lead to future research into the therapeutic use of E. elatior in alleviating the progression of DM and thus preventing nephropathy.

Zucker Diabetic Sprague Dawley rat (ZDSD): type 2 diabetes translational research model

New Findings

What is the topic of this review?

The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is in the early adoption phase of use by researchers in the fields of diabetes, including prediabetes, obesity and metabolic syndrome. It is essential that physiology researchers choose preclinical models that model human type 2 diabetes appropriately and are aware of the limitations on experimental design.

What advances does it highlight?

Our review of the scientific literature finds that although sex, age and diets contribute to variability, the ZDSD phenotype and disease progression model the characteristics of humans who have prediabetes and diabetes, including co‐morbidities.

Abstract

Type 2 diabetes (T2D) is a prevalent disease and a significant concern for global population health. For persons with T2D, clinical treatments target not only the characteristics of hyperglycaemia and insulin resistance, but also co‐morbidities, such as obesity, cardiovascular and renal disease, neuropathies and skeletal bone conditions. The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is a rodent model developed for experimental studies of T2D. We reviewed the scientific literature to highlight the characteristics of T2D development and the associated phenotypes, such as metabolic syndrome, cardiovascular complications and bone and skeletal pathologies in ZDSD rats. We found that ZDSD phenotype characteristics are independent of leptin receptor signalling. The ZDSD rat develops prediabetes, then progresses to overt diabetes that is accelerated by introduction of a timed high‐fat diet. In male ZDSD rats, glycated haemoglobin (HbA1c) increases at a constant rate from 7 to >30 weeks of age. Diabetic ZDSD rats are moderately hypertensive compared with other rat strains. Diabetes in ZDSD rats leads to endothelial dysfunction in specific vasculatures, impaired wound healing, decreased systolic and diastolic cardiac function, neuropathy and nephropathy. Changes to bone composition and the skeleton increase the risk of bone fractures. Zucker Diabetic‐Sprague Dawley rats have not yet achieved widespread use by researchers. We highlight sex‐related differences in the ZDSD phenotype and gaps in knowledge for future studies. Overall, scientific data support the premise that the phenotype and disease progression in ZDSD rats models the characteristics in humans. We conclude that ZDSD rats are an advantageous model to advance understanding and discovery of treatments for T2D through preclinical research.

Advances in the Progression and Prognosis Biomarkers of Chronic Kidney Disease

Chronic kidney disease (CKD) is one of the increasingly serious public health concerns worldwide; the global burden of CKD is increasingly due to high morbidity and mortality. At present, there are three key problems in the clinical treatment and management of CKD. First, the current diagnostic indicators, such as proteinuria and serum creatinine, are greatly interfered by the physiological conditions of patients, and the changes in the indicator level are not synchronized with renal damage. Second, the established diagnosis of suspected CKD still depends on biopsy, which is not suitable for contraindication patients, is also traumatic, and is not sensitive to early progression. Finally, the prognosis of CKD is affected by many factors; hence, it is ineviatble to develop effective biomarkers to predict CKD prognosis and improve the prognosis through early intervention. Accurate progression monitoring and prognosis improvement of CKD are extremely significant for improving the clinical treatment and management of CKD and reducing the social burden. Therefore, biomarkers reported in recent years, which could play important roles in accurate progression monitoring and prognosis improvement of CKD, were concluded and highlighted in this review article that aims to provide a reference for both the construction of CKD precision therapy system and the pharmaceutical research and development.

Urinary Transferrin and Proinflammatory Markers Predict the Earliest Diabetic Nephropathy Onset

This study aimed to determine the earliest markers of diabetic nephropathy (DN) onset with discriminative potentials from controlled diabetes (CD). Methods: Sixty male Wistar rats were allocated in three groups (20/group), the two diabetic groups CD and DN received 45 and 65 mg/kg STZ in 0.1 mole/L citrate buffer; respectively, while control group received only the vehicle. Serum/urinary levels of glomerular, tubular, oxidative and proinflammatory markers were weekly monitored. Results: Each diabetic group showed a different pattern of inflammatory; oxidative and signs of nephropathy along the study period, but none had a discriminative power until the 4^th week. At this time point, levels of urinary transferrin; serum/urinary IL-6 and TNF-α as well as urinary IL-18 were significantly higher in DN group comparing to CD (P = 0.0217, <0.0001, 0.0005, 0.0004, 0.0006, 0.0019; respectively). Predictive thresholds of these markers were calculated by receiver operating characteristic (ROC) curve that showed area under curve (AUC) of 0.9375 for transferrin with cut-off value 35.2 mg/dL, and 1.000 for serum/urinary IL-6 and TNF-α and urinary IL-18 with cut-of values 224.1, 82.11, 6.596, 125.9 and 21.86 pg/mL; respectively. Conclusion: Urinary transferrin and the inflammatory endpoints proposed in this study might represent promising biomarkers for the early DN onset.

Plant-Based versus Animal-Based Low Protein Diets in the Management of Chronic Kidney Disease

Recent data reiterate low-protein diets (LPDs) as cornerstones in the conservative management of chronic kidney disease (CKD). The reduction in proteinuria, better blood pressure control and the reduction in the rate of decline in kidney function with LPDs were reported, both in non-diabetics and diabetics patients. Supplemented, vegetarian, very-low-protein diets (sVLPD, 0.3 g/kg-day) could postpone kidney replacement therapy (KRT) initiation, mainly through the better control of metabolic disorders of advanced CKD in non-diabetic patients. Plant-based diets could ameliorate gut microbiota and appear to be superior to mixed hypoproteic diets in treating advanced CKD: better control of nitrogen balance, acid-base metabolism and bone mineral disorders. Vegetarian diets generate fewer uremic toxins and reduce salt intake and acid overload. At the same time, they can improve lipid metabolism, providing a high ratio of unsaturated to saturated fatty acids, as well as insulin resistance.

Diabetic Nephropathy - possibilities of early laboratory diagnostics and course prediction (review of literature)

The medical and social significance of diabetes mellitus is determined by a progressive increase in the incidence of the disease, as well as the development of disabling and reducing the quality of life of macro- and microvascular complications in patients of working age, in particular, with the development of diabetic nephropathy (DN), which develops in one third of patients with type 1 and 2 diabetes. DN is the third leading cause of death after diseases of the cardiovascular system and oncological pathologies. In this regard, the identification of DN at the early stages is an important task both from the standpoint of prevention and a more favorable prognosis of the course of diabetes. This review presents data on the possibilities of early diagnosis of DN using blood and urine biomarkers, as well as information on their diagnostic and prognostic value. The analysis of the interpretation of the indicator of microalbuminuria in type 1 and 2 diabetes was carried out. In addition, the literature data of recent years on the informative value of determining markers of podocyte damage, on the role of oxidative stress products, immune-inflammatory factors, and vascular endothelial growth factor in the process of the onset and development of DN are presented. The possibility of their practical use for the diagnosis of DN in clinical practice is discussed. The literature search for this review was carried out using the databases of the RSCI, CyberLeninka, Scopus, Web of Science, MedLine, PubMed for the period from 2011 to 2021. using the following keywords: diabetes mellitus, diabetic nephropathy, markers of diabetic nephropathy; kidney damage, early diagnosis of diabetic nephropathy.

Elevated Serum Levels of Carbohydrate Antigen 72-4 in Diabetic Kidney Disease

The aim of this study was to determine whether carbohydrate antigen 72-4 (CA72-4) is elevated in diabetic kidney disease (DKD), and examine the association between urinary albumin-to-creatinine ratio (UACR) and CA72-4 in patients with type 2 diabetes mellitus (T2DM). Non-dialysis patients with T2DM (n=296) and 90 healthy controls were recruited in this study. CA72-4 level was measured by electrochemiluminescence immunoassay. DKD was defined as UACR≥ 30 mg/g in the absence of a urinary infection or other renal diseases. We found that patients with DKD had significantly higher serum CA72-4 levels compared to those with normoalbuminuria and healthy controls. Positive rates of CA72-4 increased gradually and markedly from normoalbuminuria to microalbuminuria and to macroalbuminuria in diabetic patients (7.5, 11.2, and 17.4%, respectively; P for trend< 0.05). CA72-4 also showed a positive correlation with UACR (r=0.288, P< 0.01). Logistic regression analysis revealed the association of increased UACR with an increased odds ratio of elevation of CA72-4 levels (P for trend< 0.05) after multivariable adjustment. In conclusion, serum levels of CA72-4 increase abnormally with the increase in urinary albumin excretion, which affects the specificity of diagnosis of malignancies. An appropriate interpretation of CA72-4 is essential to prevent unnecessary and even hazardous diagnostic procedures in patients with T2DM.

Baicalin improves podocyte injury in rats with diabetic nephropathy by inhibiting PI3K/Akt/mTOR signaling pathway

Objective

To investigate the effect of baicalin on diabetic nephropathy (DN) rats and podocytes and its mechanism.

Methods

The rat models with DN were established by high-fat and high-sugar diet and intraperitoneal injection of streptozotocin. The fasting blood glucose (FBG) and weight of rats in each group were measured at 0, 1, 2, 3, and 4 weeks. Their biochemical indicators, expression of inflammatory, and antioxidant factors were measured using an automatic biochemical analyzer together with ELISA. Hematoxylin-eosin staining and periodic acid-schiff staining were used to observe the morphological changes in the kidneys of rats in each group. Finally, the expressions of related molecules and PI3K/Akt/mTOR signaling pathway proteins in renal tissues and podocytes were examined by qRT-PCR and Western blot.

Results

Compared with the DN group, the FBG and weight, serum creatinine, blood urea nitrogen, total cholesterol, triacylglycerol, microalbumin, and albumin/creatinine ratio were all significantly decreased in the Baicalin treatment groups in a concentration-dependent manner. The levels of inflammatory factors in kidney tissue and podocytes were decreased. In addition, the activities of lactate dehydrogenase and malondialdehyde in tissue were decreased, while the superoxide dismutase was increased. The pathological sections showed that glomerular atrophy and glomerular basement membrane thickening caused by hyperglycemia were improved in the Baicalin treatment groups. Meanwhile, baicalin inhibited the downregulation of Nephrin and Podocin expressions and upregulation of Desmin expression caused by DN, and inhibited the expressions of p-PI3K, p-Akt, and p-mTOR proteins.

Conclusion

Baicalin slows down podocyte injury caused by DN by inhibiting the activity of PI3K/Akt/mTOR signaling pathway.

Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio as novel risk markers for diabetic nephropathy in patients with type 2 diabetes

Introduction

Diabetes mellitus causes serious complications such as diabetic nephropathy. Diabetic nephropathy is now the most common reason of chronic kidney disease. Inflammation plays a crucial role in development and progression of diabetic nephropathy. The aim of this study was to evaluate the relationship of Inflammatory markers (neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio) with diabetic nephropathy in Syrian patients.

Materials and methods

A total of 158 patients with type 2 diabetes mellitus were distributed into three groups according to urinary albumin-to-creatinine ratio: Group A, type 2 diabetic patients with normoalbuminuria (urinary albumin-to-creatinine ratio <30 mg/g); Group B, type 2 diabetic patients with microalbuminuria (urinary albumin-to-creatinine ratio = 30–300 mg/g); Group C, type 2 diabetic patients with macroalbuminuria (urinary albumin-to-creatinine ratio ≥300 mg/g). Levels of inflammatory markers (neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio) were recorded and compared among the three groups.

Results

Significant differences were detected between the groups in terms of neutrophil-to-lymphocyte ratio (p = 0.000) and platelet-to-lymphocyte ratio (p = 0.000). Receiver operating characteristic curve analysis of inflammatory markers and microalbuminuria prediction demonstrated an area under curve (AUC) of 0.869 for neutrophil-to-lymphocyte ratio (confidence interval: 0.813–0.926, p = 0.000) and 0.739 for platelet-to-lymphocyte ratio (confidence interval: 0.662–0.815, p = 0.000).

Conclusion

Increased neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio were significantly correlated with diabetic nephropathy, and high neutrophil-to-lymphocyte ratio & platelet-to-lymphocyte ratio may be served as a predictor and a prognostic risk marker of diabetic nephropathy.

Advanced-Glycation End-Products Induce Podocyte Injury and Contribute to Proteinuria

The prevalence of diabetes reaches epidemic proportions. Diabetes is the leading cause of end-stage kidney disease (ESKD) since 30–40% of diabetic patients develop diabetic nephropathy. Albuminuria and glomerular filtration rate used to assess kidney function are considered surrogate outcomes of chronic kidney disease. The search for a biomarker that predicts progression to diabetic kidney disease is intense. We analyzed the association of serum advanced glycation end-products (AGEs) index (AGI) with impaired kidney function in poorly controlled type II diabetic patients. We observed an association between AGI and impaired kidney function in microalbuminuria patients with hyperglycemia. A significant association between AGEs, particularly carboxymethyl lysine (CML), and impaired kidney function were observed. Administration of AGEs to mice showed heavy proteinuria and glomerular abnormalities. Reduced podocyte number in mice administered with AGEs could be attributed to the epithelial-mesenchymal transition of podocytes. Our study suggests CML could be independently related to the podocyte injury and the risk of DN progression to ESKD in patients with microalbuminuria. AGEs in general or CML could be considered a prognostic marker to assess diabetic kidney disease.

Poor Glycemic Control Can Increase the Plasma Kidney Injury Molecule-1 Concentration in Normoalbuminuric Children and Adolescents with Diabetes Mellitus

Diabetic nephropathy (DN) is a serious microvascular complication in childhood diabetes and microalbuminuria has been a solid indicator in the assessment of DN. Nevertheless, renal injury may still occur in the presence of normoalbuminuria (NA) and various tubular injury biomarkers have been proposed to assess such damage. This case-controlled study aimed to evaluate plasma and urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 (KIM-1) levels in diabetic children particularly in those with normo- and high-NA stages and determine their role in predicting DN. Fifty-four children/adolescents with type 1 and 2 diabetes and forty-four controls aged 7–18 years were included. The baseline clinical and laboratory characteristics including plasma and urinary biomarkers were compared. The plasma KIM-1 levels were significantly higher in diabetic children than in the controls and in high-NA children than normo-NA children. Glycosylated hemoglobin (HbA1c) was identified as a significant risk factor for increased plasma KIM-1. The optimal cutoff for HbA1c when the plasma KIM-1 was > 23.10 pg/mL was 6.75% with an area under the curve of 0.77. For diabetic children with mildly increased albuminuria, the plasma KIM-1 complementary to MA may help increase the yield of detecting DN. Our findings also suggested an HbA1c cutoff of 6.75% correlated with increased plasma KIM-1.

Diagnostic efficacy of serum and urinary netrin-1 in the early detection of diabetic nephropathy

This study aimed to assess the diagnostic value of serum and urinary netrin-1 in patients with type 2 diabetes mellitus (T2DM) at different stages of diabetic nephropathy (DN) and to compare its efficacy of estimation in serum with that in the urine. This study was carried out on 135 patients with T2DM and 45 healthy subjects. The patients with diabetes were divided according to urinary albumin creatinine ratio (UACR) into: T2DM with normoalbuminuria, incipient DN with microalbuminuria, and overt DN with macroalbuminuria groups. Serum and urinary levels of netrin-1 were measured by ELISA. The mean levels of serum and urinary netrin-1 were significantly higher in the microalbuminuric and macroalbuminuric patients with DN than those in the normoalbuminuric patients with T2DM, with the highest values detected in macroalbuminuric patients with DN. Urinary netrin-1 level was significantly higher in the normoalbuminuric T2DM group than control group, whereas no significant difference existed regarding serum netrin-1 level. In T2DM groups, the urinary and serum netrin-1 correlated with each other and were independently related to fasting blood glucose, UACR, and estimated glomerular filtration rate. Receiver operating characteristic curve analysis showed that the area under the curve of urinary netrin-1 was 0.916 which is significantly higher than that of serum netrin-1 (0.812) for the detection of incipient DN and reached 0.938 on coestimation of both urinary and serum netrin-1. In conclusion, netrin-1 is a potential diagnostic marker for early detection of DN with its estimation in urine has higher accuracy than that of serum.

Induction of PDCD4 by albumin in proximal tubule epithelial cells potentiates proteinuria-induced dysfunctional autophagy by negatively targeting Atg5

The precise molecular mechanism of autophagy dysfunction in type 1 diabetes is not known. Herein, the role of programmed cell death 4 (PDCD4) in autophagy regulation in the pathogenesis of diabetic kidney disease (DKD) in vivo and in vitro was described. It was found that Pdcd4 mRNA and protein was upregulated in the streptozotocin (STZ)-induced DKD rats. In addition, a unilateral ureteral obstruction mouse model displayed an upregulation of PDCD4 in the disease group. kidney biopsy samples of human DKD patients showed an upregulation of PDCD4. Furthermore, western blotting of the STZ-induced DKD rat tissues displayed a low microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, as compared to the control. It was found that albumin overload in cultured PTEC could upregulate the expression of PDCD4 and p62, and decrease the expression of LC3-II and autophagy-related 5 (Atg5) proteins. The knockout of Pdcd4 in cultured PTECs could lessen albumin-induced dysfunctional autophagy as evidenced by the recovery of Atg5 and LC3-II protein. The forced expression of PDCD4 could further suppress the expression of crucial autophagy-related gene Atg5. Herein, endogenous PDCD4 was shown to promote proteinuria-induced dysfunctional autophagy by negatively regulating Atg5. PDCD4 might therefore be a potential therapeutic target in DKD.

Cardio- and reno-protective effects of dipeptidyl peptidase III in diabetic mice

Diabetes mellitus (DM) causes injury to tissues and organs, including to the heart and kidney, resulting in increased morbidity and mortality. Thus, novel potential therapeutics are continuously required to minimize DM-related organ damage. We have previously shown that dipeptidyl peptidase III (DPPIII) has beneficial roles in a hypertensive mouse model, but it is unknown whether DPPIII has any effects on DM. In this study, we found that intravenous administration of recombinant DPPIII in diabetic db/db mice for 8 weeks suppressed the DM-induced cardiac diastolic dysfunctions and renal injury without alteration of the blood glucose level. This treatment inhibited inflammatory cell infiltration and fibrosis in the heart and blocked the increase in albuminuria by attenuating the disruption of the glomerular microvasculature and inhibiting the effacement of podocyte foot processes in the kidney. The beneficial role of DPPIII was, at least in part, mediated by the cleavage of a cytotoxic peptide, named Peptide 2, which was increased in db/db mice compared with normal mice. This peptide consisted of nine amino acids, was a digested fragment of complement component 3 (C3), and had an anaphylatoxin-like effect determined by the Miles assay and chemoattractant analysis. The effect was dependent on its interaction with the C3a receptor and protein kinase C-mediated RhoA activation downstream of the receptor in endothelial cells. In conclusion, DPPIII plays a protective role in the heart and kidney in a DM animal model through cleavage of a peptide that is a part of C3.

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.

Type 2 diabetes mellitus management in patients with chronic kidney disease: an update

Diabetes mellitus (DM) is a chronic multisystem disease. Diabetic nephropathy (DN) is one of its significant microvascular complications, associated with increased morbidity and mortality. The aim of this article is to review the literature regarding the latest advances in the management of type 2 DM (T2DM) in patients with chronic kidney disease (CKD). We initially refer to the screening guidelines, the diagnostic tests used, the need for novel biomarkers in DN, the recent advances in high-risk patient identification, the recommended glycemic targets, and concerns regarding the accuracy of HbA1c in these patients. Then, a detailed explanation of the appropriate medical management based on evidence from recent trials is presented, analyzed, and discussed. All patients with T2DM should be screened for albuminuria at initial diagnosis and annually thereafter. Proteomics and metabolomics today represent promising diagnostic tools. Optimal glycemic control, with individualized HbA1c targets, is fundamental for reduced onset or delayed progression of DN and microvascular complications, in general. This can be enhanced by lifestyle modifications and pharmacological interventions when needed. Metformin represents the first pharmacological step, with, recently, a broadened indication for patients with impaired renal function. If HbA1c remains above the target in patients with established CKD, SGLT2i or GLP-1 RA are the preferred second-line agents, as introduced in all new guidelines. This change was the result of recent landmark trials that highlighted the superiority of the two aforementioned medication categories in terms of both renal and cardiovascular outcomes.

Urinary proteins detected using modern proteomics intervene in early type 2 diabetic kidney disease – a pilot study

Aim: An advanced proteomics platform for protein biomarker discovery in diabetic chronic kidney disease (DKD) was developed, validated and implemented. Materials & methods: Three Type 2 diabetes mellitus patients and three control subjects were enrolled. Urinary peptides were extracted, samples were analyzed on a hybrid LTQ-Orbitrap Velos Pro instrument. Raw data were searched using the SEQUEST algorithm and integrated into Proteome Discoverer platform. Results & discussion: Unique peptide sequences, resulted sequence coverage, scoring of peptide spectrum matches were reported to albuminuria and databases. Five proteins that can be associated with early DKD were found: apolipoprotein AI, neutrophil gelatinase-associated lipocalin, cytidine deaminase, S100-A8 and hemoglobin subunit delta. Conclusion: Urinary proteome analysis could be used to evaluate mechanisms of pathogenesis of DKD.

Renoprotective effects of Tilianin in diabetic rats through modulation of oxidative stress via Nrf2-Keap1 pathway and inflammation via TLR4/MAPK/NF-κB pathways

The present study was undertaken to assess the protective effects of Tilianin (TN) on type-2 diabetes-induced renal dysfunction in experimental rats. Diabetes was induced by injecting Nicotinamide (110 mg/kg) and streptozotocin (55 mg/kg) by i.p. and then the rats were treated with TN (10 and 20 mg/kg) daily by oral gavage for 28 days. TN treatment significantly decreases the BUN, creatinine, 24-hour urinary protein, urea, uric acid, and albumin protein levels. The protein of expression of Nrf2, NQO1, and HO-1 was augmented while the expression of Keap-1 decreased significantly. TN also reduces the oxidative/nitrosative status by lowering MDA content, NO, and MPO levels. TN exerted anti-inflammatory effects by suppressing TLR4/NF-κB/MAPK signaling cascades and inhibiting MyD88, TRAF6, IκBα, p38MAPK, JNK, and ERK2 in the diabetic rats. Histopathological findings supported the biochemical and molecular results. The results showed that TN modulated Nrf2-Keap1 and TLR4/MAPK/NF-κB signaling pathways and provided significant protection against diabetes-induced renal dysfunction.

Efficacy and safety of evogliptin treatment in patients with type 2 diabetes: A multicentre, active-controlled, randomized, double-blind study with open-label extension (the EVERGREEN study)

AIM

To investigate the efficacy and safety of evogliptin compared with linagliptin in patients with type 2 diabetes.

MATERIALS AND METHODS

In this 12-week, multicentre, randomized, double-blind, active-controlled, and 12-week open-label extension study, a total of 207 patients with type 2 diabetes who had HbA1c levels of 7.0%-10.0% were randomized 1:1 to receive evogliptin 5 mg (n = 102) or linagliptin 5 mg (n = 105) daily for 12 weeks. The primary efficacy endpoint was the change from baseline HbA1c at week 12. The secondary endpoint was the change in the mean amplitude of glycaemic excursion (MAGE) assessed by continuous glucose monitoring. In the extension study conducted during the following 12 weeks, evogliptin 5 mg daily was administered to both groups: evogliptin/evogliptin group (n = 95) and linagliptin/evogliptin group (n = 92).

RESULTS

After 12 weeks of treatment, the mean change in HbA1c in the evogliptin group and in the linagliptin group was -0.85% and -0.75%, respectively. The between-group difference was -0.10% (95% CI: -0.32 to 0.11), showing non-inferiority based on a non-inferiority margin of 0.4%. The change in MAGE was -24.6 mg/dL in the evogliptin group and -16.7 mg/dL in the linagliptin group. These values were significantly lower than the baseline values in both groups. However, they did not differ significantly between the two groups. In the evogliptin/evogliptin group at week 24, HbA1c decreased by -0.94%, with HbA1c values of <7.0% in 80.2% of the patients. The incidence and types of adverse events were comparable between the two groups for 24 weeks.

CONCLUSION

In this study, the glucose-lowering efficacy of evogliptin was non-inferior to linagliptin. It was maintained at week 24 with a 0.94% reduction in HbA1c. Evogliptin therapy improved glycaemic variability without causing any serious adverse events in patients with type 2 diabetes.

Urinary Cyclophilin A and serum Cystatin C as biomarkers for diabetic nephropathy in children with type 1 diabetes

BACKGROUND

Currently, microalbuminuria is the gold standard for detection and prediction of diabetic nephropathy (DN). However, microalbuminuria appears once significant kidney damage has actually occurred.

OBJECTIVES

We investigated the diagnostic role of urinary Cyclophilin-A (uCypA), uCypA/creatinine ratio (uCypA/Cr) and serum Cystatin-C (sCysC) as biomarkers for early detection of DN in children with type 1 diabetes mellitus (T1DM) of short duration (2-5 years) before microalbuminuria emerges.

METHODS

uCypA, uCypA/Cr, and sCysC levels were assessed in three age- and sex-matched groups; microalbuminuric diabetic group (n = 31), normoalbuminuric diabetic group (n = 29), and control group (n = 30). Glomerular filtration rate was estimated (eGFR) based on both serum creatinine (eGFR-Cr) and sCysC (eGFR-CysC).

RESULTS

Significantly higher sCysC and lower eGFR-CysC were detected in both diabetic groups compared to controls and in microalbuminuric compared to normoalbuminuric group. No detected significant difference in eGFR-Cr values across the studied groups. Both uCypA and uCypA/Cr were significantly elevated in microalbuminuric compared to both normoalbuminuric and control groups with no difference between normoalbuminuric and control groups. Prediction of microalbuminuria was conducted using sCysC with area under curve up to 0.980. Combined use of sCysC and uCypA had better diagnostic value than uCypA alone.

CONCLUSION

sCysC is a promising early biomarker for DN in childhood T1DM before albuminuria detection. eGFR-CysC is superior to eGFR-Cr in evaluating renal status in childhood T1DM. uCypA and uCypA/Cr were useful tools in predicting microalbuminuria, although not regarded as diagnostic biomarkers for early-stage DN in T1DM children by the current study.

Short-term renal and metabolic effects of low dose vildagliptin treatment added-on insulin therapy in non-proteinuric patients with type 2 diabetes: open-label randomized prospective study

Objective The aim of this randomized comparative study was to assess renal and metabolic effects of vildagliptin in insulin-treated type 2 diabetes (T2DM) patients without overt chronic kidney disease. Subjects and methods We randomized 47 insulin-treated non-proteinuric patients with satisfactory controlled T2DM and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m 2 either to continue insulin therapy (control) or to receive combined insulin-vildagliptin treatment (VIG group). We assessed eGFR using serum creatinine (eGFRcreat), cystatin C (eGFRcys), and both (eGFRcreat-cys), and urinary creatinine-adjusted excretion of albumin (UACR), type IV collagen (uCol IV/Cr), and neutrophil gelatinase-associated lipocalin (uNGAL/Cr) at baseline and after 6 months of treatment. Results Study groups were comparable in terms of age and sex (60.1 ± 6.1 years and 42.9% men in control group vs. 60.8 ± 5.2 years and 39.1% in VIG group). After 6 months of treatment, there were no significant changes in main assessed parameters in control group. VIG group demonstrated significant decrease in HbA1c, diastolic blood pressure, frequency of hypoglycemia, and high-sensitivity C-reactive protein level as compared to the changes in control group. While eGFRcreat, UACR, and uNGAL/Cr showed no significant changes after vildagliptin addition, eGFRcys, eGFRcreat-cys, and uCol IV/Cr changed significantly in comparison with control group (+7.0% [3.7;13.3]; +5.1% [1.4;8.5]; -32,8% [-55.8;-24.4], respectively, p < 0.01 each). Correlation and regression analysis revealed glucose-independent pattern of these changes. Conclusion Addition of vildagliptin to ongoing insulin therapy in patients with T2DM was associated with a reduction in uCol IV/Cr and an increase in eGFRcys and eGFRcreat-cys, independent of T2DM control parameters.

Renal tubular Bim mediates the tubule-podocyte crosstalk via NFAT2 to induce podocyte cytoskeletal dysfunction

Diabetic nephropathy (DN) is mainly regarded as diabetic glomerulopathy, and its progression is tightly correlated with tubular epithelial lesions. However, the underlying molecular mechanisms linking tubular damage and glomerulopathy are poorly understood.

Methods: We previously reported that the upregulation of Bim mediated proximal tubular epithelial cell (PTEC) apoptosis and was crucial in the early stages of DN. Herein we modulated Bim expression in PTECs and subsequently determined podocyte (PC) cytoskeletal arrangement by building a Transwell co-culture system in high glucose (HG).

Results: Compared to normal glucose, exposure to 40 mM of HG for 48 h induced significant expression of Bim in PTECs and disorganization in the PC cytoskeleton. When cocultured with PTECs in HG, exacerbated filamentous actin (F-actin) rearrangement and reduced synaptopodin levels were detected in PCs. In contrast, gene knockdown of Bim in PTECs was correlated with the absence of PC cytoskeletal disorganization. NFAT2 level and its nuclear translocation in PTECs were decreased by suppressing Bim expression. Upregulating NFAT2 disrupted the beneficial effects on F-actin organization in PCs obtained by inhibiting Bim. LncRNA microarray analysis identified NONHSAT179542.1, which was implicated in Bim-mediated PC cytoskeletal disorder.

Conclusion: Our study clarified the functional role of Bim, a pro-apoptotic factor, which is involved in the crosstalk between PTECs and PCs. Bim promotes NFAT2 activation in PTECs, inducing the downregulation of lncRNA NONHSAT179542.1 in PCs, contributing to the cytoskeletal damage. Identification of the role of the Bim/NFAT2 pathway may represent a promising research direction for a better understanding of DN development.

Unstably controlled systolic blood pressure trajectories are associated with markers for kidney damage in prediabetic population: results from the INDEED cohort study

Background

The association between blood pressure change and kidney damage in patients with abnormal blood glucose remains unclear. The current study aimed to identify systolic blood pressure (SBP) trajectories among the prediabetic population and to determine their association with kidney damage after a long-term follow-up.

Methods

The incidence, development, and prognosis of diabetic kidney disease (INDEED) study is nested in the Kailuan cohort study with a focus on population with diabetes and prediabetes. We screened out people with prediabetes in 2006 and with more than three SBP records from 2006 to 2014 biennially. We used the latent mixture modeling to fit five groups of trajectories of SBP. In 2016, estimated glomerular filtration rate (eGFR), urinary albumin creatinine ratio (uACR), and urinary α1-microglobulin (α1MG), transferrin and α1-acid glycoprotein were measured, and the association between SBP trajectories and these markers was analyzed by linear regression and logistic regression models.

Results

Totally, 1451 participants with prediabetes and without kidney damage were identified in 2006. Five heterogeneous SBP trajectories were detected based on the longitudinal data from 2006 to 2014, as low-stable group (n = 323), moderate-stable group (n = 726), moderate-increasing group (n = 176), moderate-decreasing group (n = 181), and high-stable group (n = 45). Linear regression analysis showed that the moderate and high SBP groups had lower eGFR, higher uACR, higher urinary α1MG, higher transferrin, and higher α1-acid glycoprotein than the low-stable group. Multivariable analysis attenuated the association but did not change the statistical significance.

Conclusions

Prediabetic patients with persistent high-level SBP trajectory or gradually increased SBP trajectory had severer kidney damage during follow-up.

Hyperinsulinemia contributes to impaired-glucose-tolerance-induced renal injury via mir-7977/SIRT3 signaling

Background:

Increasing evidence indicates that impaired glucose tolerance (IGT) is independently associated with chronic kidney disease, but the characteristics and underlying mechanisms remain largely unknown.

Methods:

Here, the cross-sectional study was performed to study the characteristics of IGT-induced renal injury (IGT-RI). Furthermore, urine microRNA profile was evaluated and microRNAs involved in tubular injury were determined by in-vitro experiments.

Results:

It was found that 12.1% of IGT patients had microalbuminuria, which we termed “IGT-RI.” Overall, 100% of patients with IGT-RI exhibited reabsorption dysfunction and 58.3% had structural damage in the renal tubules. Two-hour postprandial insulin, retinol-binding protein, and N-acetyl-β-glucosaminidase were significantly associated with microalbuminuria and they were independent risk factors for IGT-RI. The expression of mir-7977 was altered in IGT-RI patients and may be involved in cellular response to oxidative stress. In proximal tubule epithelial cells in vitro, a high level of insulin increased the expression of mir-7977 and decreased that of sirtuin 3 (SIRT3), leading to oxidative stress. Overexpression of mir-7977 further decreased SIRT3 expression, whereas inhibition of mir-7977 had the opposite effect. Furthermore, mir-7977 can bind to the 3′-untranslated region of SIRT3 mRNA and inhibit its expression. Moreover, inhibition of SIRT3 reduced the expression of cubilin and the endocytosis of albumin.

Conclusions:

In conclusion, IGT-RI mainly manifests as tubular injury, especially reabsorption dysfunction. Compensatory hyperinsulinemia may be involved. A high level of insulin can activate mir-7977/SIRT3 signaling, resulting in tubular injury by inducing oxidative stress as well as reabsorption dysfunction by inhibiting the expression of cubilin, ultimately contributing to IGT-RI.

Detection of renal biomarkers in chronic kidney disease using microfluidics: progress, challenges and opportunities

Chronic kidney disease (CKD) typically evolves over many years in a latent period without clinical signs, posing key challenges to detection at relatively early stages of the disease. Accurate and timely diagnosis of CKD enable effective management of the disease and may prevent further progression. However, long turn-around times of current testing methods combined with their relatively high cost due to the need for established laboratory infrastructure, specialized instrumentation and trained personnel are drawbacks for efficient assessment and monitoring of CKD, especially in underserved and resource-poor locations. Among the emerging clinical laboratory approaches, microfluidic technology has gained increasing attention over the last two decades due to the possibility of miniaturizing bioanalytical assays and instrumentation, thus potentially improving diagnostic performance. In this article, we review current developments related to the detection of CKD biomarkers using microfluidics. A general trend in this emerging area is the search for novel, sensitive biomarkers for early detection of CKD using technology that is improved by means of microfluidics. It is anticipated that these innovative approaches will be soon adopted and utilized in both clinical and point-of-care settings, leading to improvements in life quality of patients.

Weight-gain induced changes in renal perfusion assessed by contrast-enhanced ultrasound precede increases in urinary protein excretion suggestive of glomerular and tubular injury and normalize after weight-loss in dogs

Early detection of obesity-related glomerulopathy in humans is challenging as it might not be detected by routine biomarkers of kidney function. This study's aim was to use novel kidney biomarkers and contrast-enhanced ultrasound (CEUS) to evaluate the effect of obesity development and weight-loss on kidney function, perfusion, and injury in dogs. Sixteen healthy lean adult beagles were assigned randomly but age-matched to a control group (CG) (n = 8) fed to maintain a lean body weight (BW) for 83 weeks; or to a weight-change group (WCG) (n = 8) fed the same diet to induce obesity (week 0-47), to maintain stable obese weight (week 47-56) and to lose BW (week 56-83). At 8 time points, values of systolic blood pressure (sBP); serum creatinine (sCr); blood urea nitrogen (BUN); serum cystatin C (sCysC); urine protein-to-creatinine ratio (UPC); and urinary biomarkers of glomerular and tubular injury were measured. Glomerular filtration rate (GFR) and renal perfusion using CEUS were assayed (except for week 68). For CEUS, intensity- and time-related parameters representing blood volume and velocity were derived from imaging data, respectively. At 12-22% weight-gain, cortical time-to-peak, representing blood velocity, was shorter in the WCG vs. the CG. After 37% weight-gain, sCysC, UPC, glomerular and tubular biomarkers of injury, urinary immunoglobulin G and urinary neutrophil gelatinase-associated lipocalin, respectively, were higher in the WCG. sBP, sCr, BUN and GFR were not significantly different. After 23% weight-loss, all alterations were attenuated. Early weight-gain in dogs induced renal perfusion changes measured with CEUS, without hyperfiltration, preceding increased urinary protein excretion with potential glomerular and tubular injury. The combined use of routine biomarkers of kidney function, CEUS and site-specific urinary biomarkers might be valuable in assessing kidney health of individuals at risk for obesity-related glomerulopathy in a non-invasive manner.

Assessment of two novel renal tubular proteins in type 2 diabetic patients with nephropathy

Nephropathy is a common health issue associated with type 2 diabetes mellitus (T2DM). Treatment of diabetic nephropathy (DN) in an early stage can effectively inhibit its progression. Albuminuria is the currently accepted marker for detection of DN.This study aims to evaluate the urinary level of two novel renal tubular proteins (cyclophilin A and periostin) in patients with T2DM and among different nephropathy stages and also to validate the diagnostic accuracy of both cyclophilin A and periostin as potential markers for early prediction of DN relative to albuminuria.This cross-sectional study recruited 137 patients with T2DM, and they were divided based on their urinary albumin:creatinine ratio into T2DM with normoalbuminuria (group II), incipient T2DN with microalbuminuria (group III) and overt T2DN with macroalbuminuria (group IV) beside 41 healthy subjects as group I Cyclophilin A and periostin were measured in the urine using ELISA. Diagnostic accuracy of both markers was determined for prediction of DN via receiver operating characteristic curve analyses.Urinary cyclophilin A and periostin levels were significantly higher in DN groups when compared with T2DM with normoalbuminuria group. For prediction of incipient and overt DN, areas under the curve (AUCs) of periostin were 0.954, 0.997 and cyclophilin A were 0.914, 0.937, respectively. AUCs of periostin were higher than that for cyclophilin A with a significant AUC difference (p=0.022) in overt DN stage.Periostin and cyclophilin A could be regarded as a potential urinary biomarker for early prediction of DN. Periostin exhibits a higher diagnostic accuracy than urinary cyclophilin A specifically in overt DN stage.

Diabetic Nephropathy Assessment: Microtubule-Associated Protein 1 Light-Chain 3B a New Promising Biomarker

Autophagy is a highly conserved pathway. Impairment of autophagy is implicated in the pathogenesis of diabetic nephropathy. The current study applied a bioinformatics analysis to retrieve promising autophagy biomarker relevant diabetic nephropathy. Urinary expression of Microtubule-associated protein 1 light-chain 3B (LC3B) RNA was assessed. Urine samples of 86 type II diabetic kidney disease Egyptian patients (albuminuria group) were provided to quantify urinary expression of LC3B. A group of 30 healthy volunteers were also enrolled in addition to non-albuminuria group including 44 patients. Our study revealed a cut-off value for urinary LC3B expression level that was calculated by receiver-operating characteristic curve as 0.866. Sensitivity and specificity of LC3B were 83.7 and 78.4% respectively. The positivity rate of urinary LC3B expression level was significantly lower in diabetic nephropathy patients than control group. LC3B has great clinical value as promising biomarker in diabetic nephropathy assessment.

Diabetic kidney diseases revisited: A new perspective for a new era

BACKGROUND

Globally, diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. As the most common microvascular complication of diabetes, DKD is a thorny, clinical problem in terms of its diagnosis and management. Intensive glucose control in DKD could slow down but not significantly halt disease progression. Revisiting the tremendous advances that have occurred in the field would enhance recognition of DKD pathogenesis as well as improve our understanding of translational science in DKD in this new era.

SCOPE OF REVIEW

In this review, we summarize advances in the understanding of the local microenvironmental changes in diabetic kidneys and discuss the involvement of genetic and epigenetic factors in the pathogenesis of DKD. We also review DKD prevalence changes and analyze the challenges in optimizing the diagnostic approaches and management strategies for DKD in the clinic. As we enter the era of 'big data', we also explore the possibility of linking systems biology with translational medicine in DKD in the current healthcare system.

MAJOR CONCLUSION

Newer understanding of the structural changes of diabetic kidneys and mechanisms of DKD pathogenesis, as well as emergent research technologies will shed light on new methods of dealing with the existing clinical challenges of DKD.

Urinary Amino-Terminal Pro–C-Type Natriuretic Peptide: A Novel Marker of Chronic Kidney Disease in Diabetes

BACKGROUND

Chronic renal inflammation and fibrosis are common sequelae in diabetes mellitus (DM) and are major causes of premature mortality. Although upregulation of NPPC expression occurs in response to renal inflammation in experimental animals, nothing is known of the molecular forms of C-type natriuretic peptide (CNP) products in urine of people with DM or links with renal function.

METHODS

ProCNP products in urine were characterized with HPLC and a range of antisera directed to specific epitopes of amino-terminal proCNP (NTproCNP). The 5-kDa intact peptide was quantified in spot urine samples from healthy adults and 202 participants with DM selected to provide a broad range of renal function.

RESULTS

The predominant products of proCNP in urine were consistent with the 2-kDa fragment (proCNP 3–20) and a smaller peak of intact (5-kDa) fragment (proCNP 1–50, NTproCNP). No peaks consistent with bioactive forms (proCNP 82–103, 50–103) were identified. The urine NTproCNP to creatinine ratio (NCR) was more reproducible than the albumin to creatinine ratio (ACR) and strongly associated with the presence of chronic kidney disease. In models predicting independence, among 10 variables associated with renal function in DM, including plasma NTproCNP, only 3 (sex, ACR, and plasma creatinine) contributed to NCR.

CONCLUSIONS

Characterization of the products of proCNP in urine confirmed the presence of NTproCNP. In spot random urine from study participants with DM, NCR is inversely associated with estimated glomerular filtration rate. In contrast to ACR, NCR reflects nonvascular factors that likely include renal inflammation and fibrosis.

The association between thyroid dysfunction (TD) and diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM)

BACKGROUND

Epidemiological studies have identified an association between thyroid dysfunction (TD) and various kidney diseases. In this study, the prevalence of TD in type 2 diabetic mellitus (T2DM) patients with diabetic kidney disease (DKD) was evaluated to analyse the potential association between TD and DKD in T2DM patients.

METHODOLOGY

A total of 2108 T2DM patients from Anhui Provincial Hospital were recruited in this study. Demographic and clinical characteristics were collected from 834 T2DM patients with DKD and 1274 T2DM patients without DKD (non-DKD). All patients were stratified into a number of groups based on UACR (urine albumin-to-creatinine ratio) or eGFR (estimated glomerular filtration rate): (a) A1: normoalbuminuria (<30), A2: microalbuminuria (30-300) and A3: macroalbuminuria (>300); (b) F1: normal filtration (60-139), F2: hyper filtration (≥140) and F3: low filtration (<60).

RESULTS

Significant differences were observed between the non-DKD and DKD groups (P < .05) in age, sex ratio, duration, systolic blood pressure, total cholesterol, low density lipoprotein cholesterol, serum creatinine, blood urea nitrogen, free triiodothyronine (FT3), free thyroxine (FT4) and sensitive thyrotropin hormone (sTSH). The macroalbuminuira and low filtration groups had the lowest levels of FT3 and FT4 and the highest level of sTSH, compared with all other groups (P < .0167). The prevalence of subclinical hypothyroidism in the DKD group was significantly higher than that in the non-DKD group (χ2  = 13.92, P < .01). Logistic regression analysis showed that hypothyroidism was associated with increased UACR or reduced eGFR in T2DM patients. Compared with controls, T2DM patients with hypothyroidism exhibited a higher UACR and urinary excretion of transferrin, as well as a lower excretion of urinary Tamm-Horsfall protein (THP) (P < .0167).

CONCLUSION

Subclinical hypothyroidism is more prevalent in T2DM patients with DKD than in T2DM patients without DKD. Hypothyroidism is associated with albuminuria and decreased eGFR in T2DM patients.

Key Genes Involved in Diabetic Nephropathy Investigated by Microarray Analysis

We aimed to investigate significant genes associated with diabetic nephropathy (DN), and their potential mechanisms in the process of DN pathogenesis. We downloaded the microarray data of GSE111154 from gene expression omnibus (GEO) database. First, we analyzed differentially expressed genes (DEGs) between early diabetic nephropathy (EDN) samples and nondiabetic control samples. Functional and pathway enrichment analysis was carried out. Disease-related gene sets were analyzed. Then, we constructed the protein-protein interaction (PPI) network and predicted the relation. Finally, transcriptional regulation analyses of microRNA and transcription factors were performed. Totally 554 DEGs between EDN samples and nondiabetic control samples were obtained. Enrichment analysis of disease-related gene sets showed that transforming growth factor beta 1 (TGFB1) was significantly enriched in DN. TGFB1 was involved in more pathways, such as proteoglycans in cancer, malaria, and amebiasis. Furthermore, TGFB1 had the highest degree in PPI network. In addition, TGFB1 was correlated with miR-21-5p, miR-146a-5p, and RAD21. TGFB1, miR-146a-5p, and miR-21-5p are important for DN development. Furthermore, TGFB1 may be involved in DN progression through the regulation of miR-21-5p, miR-146a-5p, and RAD21.

Urinary Cell Adhesion Molecule 1 Is a Novel Biomarker That Links Tubulointerstitial Damage to Glomerular Filtration Rates in Chronic Kidney Disease

Cell adhesion molecule 1 (CADM1) is an immunoglobulin superfamily member strongly expressed on renal tubular epithelia in the urinary tract. Enzymatic cleavage of its ectodomain increases in chronic kidney disease (CKD), and is assumed to contribute to tubulointerstitial lesion formation. Because the cleaved ectodomain fragments are likely to be released into the urine, a sandwich enzyme-linked immunosorbent assay (ELISA) system for urinary CADM1 was developed using two anti-ectodomain antibodies. Urinary CADM1 concentrations in patients with CKD based on various forms of glomerulonephritis and nephropathy (n = 127) were measured. A total of 44 patients (35%) had elevated CADM1 concentrations over the normal upper limit (362 pg/mL), with a mean of 1,727 pg/mL. Renal biopsy specimens of all patients were pathologically scored for tubulointerstitial lesions using epithelial degeneration, interstitial inflammation, and fibrosis. There were no correlations between urinary CADM1 concentrations and pathological scores or any widely used renal markers, including glomerular filtration rate (GFR), but there was a weak inverse correlation between pathological scores and GFR (R² = 0.292). Notably, this correlation gradually increased in patients with increasing CADM1 concentrations, and reached a maximum R² (0.899) at a cutoff of 1,569 pg/mL. The results of this study suggest that urinary CADM1 is a useful marker indicating tubulointerstitial damage from elevated GFR levels in CKD.

Renal function and choroidal thickness using swept-source optical coherence tomography in diabetic patients

AIM

To assess the relationship between choroidal thickness and renal function in diabetic patients.

METHODS

Cross-sectional retrospective clinical study of 42 eyes of 21 ocular treatment-naïve diabetic patients. Demographic data included: age, sex, type and course of diabetes. Ocular data included: severity of diabetic retinopathy; retinal thickness at the central macular region, as well as choroidal thickness at the central and paracentral quadrants, using automatically generated maps by swept-source optical coherence tomography; presence of cystic macular edema; and ocular axial length (AXL). Lab-test parameters included: glycated hemoglobin (HbA1c), albuminuria, albumin/creatinine ratio in urine, and glomerular filtration rate.

RESULTS

A significant negative correlation was mainly observed between several choroidal thicknesses, age (P<0.020) and ocular AXL (P<0.030). On the contrary, a significant positive correlation was found between all choroidal thicknesses, HbA1c (P<0.035) and albuminuria (P<0.040).

CONCLUSION

Choroidal thickness can represent an additional tool to help clinicians predicting the renal status in ocular treatment-naïve diabetic patients.

The role of serum and urinary biomarkers in the diagnosis of early diabetic nephropathy in patients with type 2 diabetes

Background

Previous studies have shown that a variety of biomarkers are closely related to the occurrence and development of early-stage diabetic nephropathy (DN) in patients. The aim of this study was to evaluate the role of multiple sera and urinary biomarkers in the diagnosis of early-stage DN in patients with type 2 diabetes.

Methods

We enrolled 287 patients with type 2 diabetes, who were classified into normoalbuminuria (n = 144), microalbuminuria (n = 94), or macroalbuminuria (n = 49) groups based on their urine albumin to creatinine ratios (UACR), along with 42 healthy controls. We assessed 13 biomarkers, including transferrin (Tf), immunoglobulin G (IgG), podocalyxin, neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-beta-glucosaminidase, α-1-microglobulin, 8-hydroxy-deoxyguanosine, tumor necrosis factor-alpha (TNF-α), and interleukin-18 in urine samples, along with cystatin C, total bilirubin, and uric acid in sera samples, to evaluate their diagnostic roles. From the measurements, the blood neutrophil to lymphocyte ratio was also calculated.

Results

Urinary Tf, IgG, NGAL, and TNF-α were significantly related to the UACR. We calculated the area under the receiver operating characteristic curves (area under the curve) and found that urinary IgG (0.894), NGAL (0.875), Tf (0.861), TNF-α (0.763), and the combination of urinary Tf + IgG + TNF-α + NGAL (0.922) showed good diagnostic value for early-stage DN.

Conclusions

Urinary Tf, IgG, NGAL, TNF-α, and the combination of all four biomarkers demonstrated excellent diagnostic value for early-stage DN in patients with type 2 diabetes.