TXNIP deficiency attenuates renal fibrosis by modulating mTORC1/TFEB-mediated autophagy in diabetic kidney disease

Thioredoxin-interacting protein (TXNIP) is an important regulatory protein for thioredoxin (TRX) that elicits the generation of reactive oxygen species (ROS) by inhibiting the redox function of TRX. Abundant evidence suggests that TXNIP is involved in the fibrotic process of diabetic kidney disease (DKD). However, the potential mechanism of TXNIP in DKD is not yet well understood. In this study, we found that TXNIP knockout suppressed renal fibrosis and activation of mammalian target of rapamycin complex 1 (mTORC1) and restored transcription factor EB (TFEB) and autophagy activation in diabetic kidneys. Simultaneously, TXNIP interference inhibited epithelial-to-mesenchymal transformation (EMT), collagen I and fibronectin expression, and mTORC1 activation, increased TFEB nuclear translocation, and promoted autophagy restoration in HK-2 cells exposed to high glucose (HG). Rapamycin, an inhibitor of mTORC1, increased TFEB nuclear translocation and autophagy in HK-2 cells under HG conditions. Moreover, the TFEB activators, curcumin analog C1 and trehalose, effectively restored HG-induced autophagy, and abrogated HG-induced EMT and collagen I and fibronectin expression in HK-2 cells. Taken together, these findings suggest that TXNIP deficiency ameliorates renal fibrosis by regulating mTORC1/TFEB-mediated autophagy in diabetic kidney diseases.

Placenta-derived mesenchymal stem cells protect against diabetic kidney disease by upregulating autophagy-mediated SIRT1/FOXO1 pathway

Diabetic kidney disease (DKD) is a common chronic microvascular complication of diabetes mellitus. Although studies have indicated the therapeutic potential of mesenchymal stem cells (MSCs) for DKD, the underlying molecular mechanisms remain unclear. Herein, we explored the renoprotective effect of placenta-derived MSCs (P-MSCs) and the potential mechanism of SIRT1/FOXO1 pathway-mediated autophagy in DKD. The urine microalbumin/creatinine ratio was determined using ELISA, and renal pathological changes were detected by special staining techniques. Immunofluorescence was used for detecting the renal tissue expression of podocin and nephrin; immunohistochemistry for the renal expression of autophagy-related proteins (LC3, Beclin-1, SIRT1, and FOXO1); and western blotting and PCR for the expression of podocyte autophagy- and pathway-related indicators. We found that P-MSCs ameliorated renal tubular injury and glomerular mesangial matrix deposition and alleviated podocyte damage in DKD rats. PMSCs enhanced autophagy levels and increased SIRT1 and FOXO1 expression in DKD rat renal tissue, whereas the autophagy inhibitor 3-methyladenine significantly attenuated the renoprotective effect of P-MSCs. P-MSCs improved HG-induced Mouse podocyte clone5(MPC5)injury, increased podocyte autophagy, and upregulated SIRT1 and FOXO1 expression. Moreover, downregulation of SIRT1 expression blocked the P-MSC-mediated enhancement of podocyte autophagy and improvement of podocyte injury. Thus, P-MSCs can significantly improve renal damage and reduce podocyte injury in DKD rats by modulating the SIRT1/FOXO1 pathway and enhancing podocyte autophagy.

The potential role of differentially expressed tRNA-derived fragments in high glucose-induced podocytes

The prevalence of diabetic kidney disease (DKD) is increasing annually. Damage to and loss of podocytes occur early in DKD. tRNA-derived fragments (tRFs), originating from tRNA precursors or mature tRNAs, are associated with various illnesses. In this study, tRFs were identified, and their roles in podocyte injury induced by high-glucose (HG) treatment were explored. High-throughput sequencing of podocytes treated with HG was performed to identify differentially expressed tRFs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. The expression levels of nephrin, podocin, and desmin were measured in podocytes after overexpression of tRF-1:24-Glu-CTC-1-M2 (tRF-1:24) and concomitant HG treatment. A total of 647 tRFs were identified, and 89 differentially expressed tRFs (|log2FC| ≥ 0.585; p ≤ .05) were identified in the HG group, of which 53 tRFs were downregulated and 36 tRFs were upregulated. The 10 tRFs with the highest differential expression were detected by real-time quantitative polymerase chain reaction (RT-qPCR), and these results were consistent with the sequencing results. GO analysis revealed that the biological process, cellular component, and molecular function terms in which the tRFs were the most enriched were cellular processes, cellular anatomical entities, and binding. KEGG pathway analysis revealed that tRFs may be involved in signaling pathways related to growth hormones, phospholipase D, the regulation of stem cell pluripotency, and T-/B-cell receptors. Overexpression of tRF-1:24, one of the most differentially expressed tRFs, attenuated podocyte injury induced by HG. Thus, tRFs might be potential biomarkers for podocyte injury in DKD.

The effects of Tripterygium wilfordii Hook F on renal outcomes in type 2 diabetic kidney disease patients with severe proteinuria: a single-center cohort study

AIM

Tripterygium wilfordii Hook F (TwHF) has been shown to substantially reduce proteinuria in patients with diabetic kidney disease (DKD); however, the effect of TwHF on renal outcomes in DKD remains unknown. Accordingly, we aimed to establish the effects of TwHF on renal outcomes in patients with DKD.

METHODS

Overall, 124 patients with DKD, induced by type 2 diabetes mellitus, with 24-h proteinuria > 2 g, and an estimated glomerular filtration rate > 30 mL/min/1.73 m2 were retrospectively investigated. The renal outcomes were defined as doubling serum creatinine levels or end-stage kidney disease. Kaplan-Meier curves and Cox regression analyses were performed to analyze prognostic factors for renal outcomes.

RESULTS

By the end of the follow-up, renal outcomes were observed in 23 and 11 patients in the non-TwHF and TwHF groups, respectively (p = 0.006). TwHF significantly reduced the risk of renal outcomes (adjusted hazard ratio [HR] 0.271, 95% confidence interval [CI] 0.111-0.660, p = 0.004) in patients with chronic kidney disease (CKD) G3 (adjusted HR 0.274, 95%CI 0.081-0.932, p = 0.039). Based on the Kaplan-Meier analysis, 1- and 3-year proportions of patients without renal outcomes were significantly lower in the non-TwHF group than those in the TwHF group (92.8% vs. 95.5% and 47.2% vs. 76.8%, respectively; p = 0.0018).

CONCLUSION

In DKD patients with severe proteinuria, TwHF could prevent DKD progression, especially in patients with CKD G3. A randomized clinical trial is needed to elucidate the benefits of TwHF on renal outcomes in patients with DKD.

Noninvasive Assessment of Diabetic Kidney Disease With MRI: Hype or Hope?

Owing to the increasing prevalence of diabetic mellitus, diabetic kidney disease (DKD) is presently the leading cause of chronic kidney disease and end-stage renal disease worldwide. Early identification and disease interception is of paramount clinical importance for DKD management. However, current diagnostic, disease monitoring and prognostic tools are not satisfactory, due to their low sensitivity, low specificity, or invasiveness. Magnetic resonance imaging (MRI) is noninvasive and offers a host of contrast mechanisms that are sensitive to pathophysiological changes and risk factors associated with DKD. MRI tissue characterization involves structural and functional information including renal morphology (kidney volume (TKV) and parenchyma thickness using T1- or T2-weighted MRI), renal microstructure (diffusion weighted imaging, DWI), renal tissue oxygenation (blood oxygenation level dependent MRI, BOLD), renal hemodynamics (arterial spin labeling and phase contrast MRI), fibrosis (DWI) and abdominal or perirenal fat fraction (Dixon MRI). Recent (pre)clinical studies demonstrated the feasibility and potential value of DKD evaluation with MRI. Recognizing this opportunity, this review outlines key concepts and current trends in renal MRI technology for furthering our understanding of the mechanisms underlying DKD and for supplementing clinical decision-making in DKD. Progress in preclinical MRI of DKD is surveyed, and challenges for clinical translation of renal MRI are discussed. Future directions of DKD assessment and renal tissue characterization with (multi)parametric MRI are explored. Opportunities for discovery and clinical break-through are discussed including biological validation of the MRI findings, large-scale population studies, standardization of DKD protocols, the synergistic connection with data science to advance comprehensive texture analysis, and the development of smart and automatic data analysis and data visualization tools to further the concepts of virtual biopsy and personalized DKD precision medicine. We hope that this review will convey this vision and inspire the reader to become pioneers in noninvasive assessment and management of DKD with MRI. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 2.

Genetic Risk Scores Identify People at High Risk of Developing Diabetic Kidney Disease: A Systematic Review

CONTEXT

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Measures to prevent and treat DKD require better identification of patients most at risk. In this systematic review, we summarize the existing evidence of genetic risk scores (GRSs) and their utility for predicting DKD in people with type 1 or type 2 diabetes.

EVIDENCE ACQUISITION

We searched MEDLINE, Embase, Web of Science, and Cochrane Reviews in June 2022 to identify all existing and relevant literature. Main data items sought were study design, sample size, population, single nucleotide polymorphisms of interest, DKD-related outcomes, and relevant summary measures of result. The Critical Appraisal Skills Programme checklist was used to evaluate the methodological quality of studies.

EVIDENCE SYNTHESIS

We identified 400 citations of which 15 are included in this review. Overall, 7 studies had positive results, 5 had mixed results, and 3 had negative results. Most studies with the strongest methodological quality (n = 9) reported statistically significant and favourable findings of a GRS's association with at least 1 measure of DKD.

CONCLUSION

This systematic review presents evidence of the utility of GRSs to identify people with diabetes that are at high risk of developing DKD. In practice, a robust GRS could be used at the first clinical encounter with a person living with diabetes in order to stratify their risk of complications. Further prospective research is needed.

Epidemiology of Diabetic Kidney Disease among US Veterans

Rationale

With a large number of patients and high mortality, diabetic kidney disease (DKD) imposes a significant burden on US health care. Although diabetes is the leading cause of chronic kidney disease and complications, the epidemiology of DKD in the contemporary US veteran population is generally unknown.

Objective

We aimed to estimate the rate of DKD progression and to measure the general epidemiology of DKD in the United States veteran population.

Study Design

We performed a retrospective observational research using electronic health-care records and administrative databases.

Setting

The DKD patient cohort was abstracted from the Veterans Health Administration health-record data from January 2016 to March 2022.

Participants

We defined DKD patients using the laboratory test data based on Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guidelines.

Analytic Approach

Summary statistics include the five-year cumulative incidence of progression to an advanced stage from the DKD stage at the cohort entry date and prevalence at a series of single time points.

Results

A total of 685,288 patients (male [96%], mean age 62 years, Caucasian [64%], non-Hispanic [87%]) met our eligibility criteria. The 5-year cumulative incidence of progression to an advanced DKD stage or all-cause death from DKD stages G1 A2/A3, G2 A2/A3, G3a, and G3b were 52.0%, 47.4%, 50.5%, and 60.9%, respectively. In sum, 594,082 patients were classified as moderate or high risk as per KDIGO guidelines in 2021, and stages G3a and G3b accounted for 51.2% and 25.3%, respectively, of cases.

Conclusion

More than half of DKD patients underwent a stage progression or death within 5 years. A substantial number of DKD patients at an earlier stage might be left undetermined. The study findings warrant a revision of DKD patient identification and management in US veterans.

The Role of Immune Cells in DKD: Mechanisms and Targeted Therapies

Diabetic kidney disease (DKD), is a common microvascular complication and a major cause of death in patients with diabetes. Disorders of immune cells and immune cytokines can accelerate DKD development of in a number of ways. As the kidney is composed of complex and highly differentiated cells, the interactions among different cell types and immune cells play important regulatory roles in disease development. Here, we summarize the latest research into the molecular mechanisms underlying the interactions among various immune and renal cells in DKD. In addition, we discuss the most recent studies related to single cell technology and bioinformatics analysis in the field of DKD. The aims of our review were to explore immune cells as potential therapeutic targets in DKD and provide some guidance for future clinical treatments.

Genetic or pharmacologic blockade of mPGES-2 attenuates renal lipotoxicity and diabetic kidney disease by targeting Rev-Erbα/FABP5 signaling

Diabetic kidney disease (DKD) is one of the most common complications of diabetes, and no specific drugs are clinically available. We have previously demonstrated that inhibiting microsomal prostaglandin E synthase-2 (mPGES-2) alleviated type 2 diabetes by enhancing β cell function and promoting insulin production. However, the involvement of mPGES-2 in DKD remains unclear. Here, we aimed to analyze the association of enhanced mPGES-2 expression with impaired metabolic homeostasis of renal lipids and subsequent renal damage. Notably, global knockout or pharmacological blockage of mPGES-2 attenuated diabetic podocyte injury and tubulointerstitial fibrosis, thereby ameliorating lipid accumulation and lipotoxicity. These findings were further confirmed in podocyte- or tubule-specific mPGES-2-deficient mice. Mechanistically, mPGES-2 and Rev-Erbα competed for heme binding to regulate fatty acid binding protein 5 expression and lipid metabolism in the diabetic kidney. Our findings suggest a potential strategy for treating DKD via mPGES-2 inhibition.

Molecular Targets of Novel Therapeutics for Diabetic Kidney Disease: A New Era of Nephroprotection

Diabetic kidney disease (DKD) is a chronic microvascular complication in patients with diabetes mellitus (DM) and the leading cause of end-stage kidney disease (ESKD). Although glomerulosclerosis, tubular injury and interstitial fibrosis are typical damages of DKD, the interplay of different processes (metabolic factors, oxidative stress, inflammatory pathway, fibrotic signaling, and hemodynamic mechanisms) appears to drive the onset and progression of DKD. A growing understanding of the pathogenetic mechanisms, and the development of new therapeutics, is opening the way for a new era of nephroprotection based on precision-medicine approaches. This review summarizes the therapeutic options linked to specific molecular mechanisms of DKD, including renin-angiotensin-aldosterone system blockers, SGLT2 inhibitors, mineralocorticoid receptor antagonists, glucagon-like peptide-1 receptor agonists, endothelin receptor antagonists, and aldosterone synthase inhibitors. In a new era of nephroprotection, these drugs, as pillars of personalized medicine, can improve renal outcomes and enhance the quality of life for individuals with DKD.

Investigational new drugs for the treatment of chronic renal failure: an overview of the literature

INTRODUCTION

Chronic kidney disease (CKD) is widespread throughout the world, with a high social and health impact. It is considered a 'silent killer' for its sudden onset without symptoms in the early stages of the disease. The main goal of nephrologists is to slow the progression of kidney disease and treat the associated symptoms with a range of new medications.

AREAS COVERED

The aim of this systematic review is to analyze the new investigational drugs for the treatment of chronic renal failure. Data were obtained from the available scientific literature and from the ClinicalTrials.gov website.

EXPERT OPINION

Among the drugs currently being researched, SGLT2 inhibitors appear to be the most promising drugs for the treatment of CKD, has they have slower progression of CKD and protection of cardiorenal function. An important role in the future of CKD treatment is played by autologous cell-therapy, which appears to be a new frontier in the treatment of CKD. Other therapeutic strategies are currently being investigated and have been shown to slow the progression of CKD. However, further studies are needed to determine whether these approaches may offer benefits in slowing the progression of CKD in the near future.

Association of weight-adjusted waist index and diabetic kidney disease in type 2 diabetes mellitus

Objective

The aim of this study was to investigate the relationship between weight-adjusted-waist index (WWI) and diabetic kidney disease in individuals afflicted with type 2 diabetes.

Methods

Comprehensive data were ascertained from the National Health and Nutrition Examination Survey in 2013-March 2020. Weighted univariate, multivariate logistic regression models, subgroup analyses and tests for interaction were performed. Additionally, we employed smooth curve fitting to assess linear correlations and the threshold effects were calculated by applying a binary linear regression model. Breakpoints are identified by a model with maximum likelihood ratio and a two-step recursive approach. Receiver operating characteristic curve (ROC) along with the area under the curve (AUC) value predict the capability of WWI and body mass index for diabetic kidney disease.

Results

A total of 10,661 individuals diagnosed with type 2 diabetes were included, and the overall prevalence of diabetic kidney disease was 20.74%. WWI exhibited a positive correlation with the likelihood of diabetic kidney disease in type 2 diabetes patients (OR: 1.17, 95% CI: 1.03-1.33). The results of subgroup analysis showed significant interaction for gender (P < 0.05). Among female patients, U-shaped correlations were observed with a breakpoint at 11.48. Additionally, weight-adjusted waist index (AUC = 0.664) proved to be a more effective predictor of diabetic kidney disease compared to body mass index (AUC = 0.555).

Conclusion

In patients with type 2 diabetes, increased weight-adjusted-waist index is implicated with an increased risk of diabetic kidney disease. WWI can be used as a new anthropometric index to predict diabetic kidney disease, and its predictive ability is stronger than body mass index.

Lipin-1 deficiency deteriorates defect of fatty acid β-oxidation and lipid-related kidney damage in diabetic kidney disease

Diabetic lipo-toxicity is a fundamental pathophysiologic mechanism in DM and is now increasingly recognized a key determinant of DKD. Targeting lipid metabolic disorders is an important therapeutic strategy for the treatment of DM and its complications, including DKD. This study aimed to explore the molecular mechanism of lipid metabolic regulation in kidney, especially renal PTECs, and elucidate the role of lipid metabolic related molecule lipin-1 in diabetic lipid-related kidney damage. In this study, lipin-1-deficient db/db mouse model and STZ/HFD-induced T2DM mouse model were used to determine the effect of lipin-1 on DKD development. Then RPTCs and LPIN1 knockdown or overexpressed HK-2 cells induced by PA were used to investigate the mechanism. We found that the expression of lipin-1 increased early and then decreased in kidney during the progression of DKD. Glucose and lipid metabolic disorders and renal insufficiency were found in these 2 types of diabetic mouse models. Interestingly, lipin-1 deficiency might be a pathogenic driver of DKD-to-CKD transition, which could further accelerate the imbalance of renal lipid homeostasis, the dysfunction of mitochondrial and energy metabolism in PTECs. Mechanistically, lipin-1 deficiency resulted in aggravated PTECs injury to tubulointerstitial fibrosis in DKD by downregulating FAO via inhibiting PGC-1α/PPARα mediated Cpt1α/HNF4α signaling and upregulating SREBPs to promote fat synthesis. This study provided new insights into the role of lipin-1 as a regulator for maintaining lipid homeostasis in the kidney, especially PTECs, and its deficiency led to the progression of DKD.

Associations of Angiopoietin 2 and Vascular Endothelial Growth Factor-A Concentrations with Clinical End Points

BACKGROUND

Angiopoietin 2 regulates endothelial function partially mediated by vascular endothelial growth factor-A (VEGF-A) and may play a role in diabetic kidney disease (DKD). We assessed the association of angiopoietin 2 and VEGF-A with cardiorenal outcomes and investigated the effect of canagliflozin on angiopoietin 2 and VEGF-A concentrations.

METHODS

Two thousand five hundred sixty-five study participants with DKD and available plasma samples treated with canagliflozin or placebo in the Canagliflozin and Kidney Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial were included. Angiopoietin 2 and VEGF-A concentrations were measured at baseline, year 1, and year 3. The primary composite end point of the trial was a composite of kidney failure, doubling of the serum creatinine level, and kidney or cardiovascular death.

RESULTS

Patients with the highest baseline quartile of angiopoietin 2, but not VEGF-A, concentration had the highest risk clinical profile. Treatment with canagliflozin significantly lowered concentrations of angiopoietin 2 (adjusted geometric mean ratio: 0.94; 95% confidence interval, 0.92 to 0.95; P < 0.001), but not VEGF-A. In multivariable-adjusted modeling, each 50% increment in log baseline angiopoietin 2 concentrations was associated with a higher risk of primary composite outcome (hazard ratio, 1.27; 95% confidence interval, 1.13 to 1.43). Angiopoietin 2 change at year 1 compared with baseline explained 10% of the effect of canagliflozin on the primary composite outcome. VEGF-A concentrations were not associated with outcomes, alone or in combination with angiopoietin 2.

CONCLUSIONS

Higher angiopoietin 2 levels were associated with cardiorenal risk among individuals with DKD independent of VEGF-A. Canagliflozin lowered angiopoietin 2 concentrations.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Evaluation of the Effects of Canagliflozin on Renal and Cardiovascular Outcomes in Participants With Diabetic Nephropathy, NCT02065791 .

Predicting Osteoporotic Fracture in Patients With Early-Stage Diabetic Kidney Disease Using a Radiomic Model: A Longitudinal Cohort Study

OBJECTIVE

There is an urgent need for effective predictive strategies to accurately evaluate the risk of fragility fractures in elderly patients in the early stages of diabetic kidney disease (DKD).

METHODS

This longitudinal cohort study included 715 older patients in the early stages of DKD diagnosed between January 2015 and August 2019. Patients were randomly allocated to a training cohort (n = 499) and a validation cohort (n = 216). The least absolute shrinkage and selection operator method was used to select key features for dual-energy x-ray absorptiometry-based radiomic analysis. A radiomic model was constructed using Cox proportional hazards regression. The performance of the radiomic model was compared with that of traditional fracture assessment tools through a receiver operating characteristic curve, calibration curve, and decision curve analysis.

RESULTS

Over a mean follow-up period of 4.72 ± 1.60 years, 65 participants (9.09%) experienced incident fragility fractures. Seventeen features were ultimately selected to create the radiomic model. The calibration plots of this model demonstrated satisfactory agreement between the observed and predicted outcomes. Moreover, the radiomic model outperformed traditional fracture assessment tools in both the training and validation cohorts according to the area under the receiver operating characteristic curve and decision curve analysis.

CONCLUSIONS

The novel radiomic model has demonstrated a more effective prediction of fragility fracture in elderly patients in the early stages of DKDcompared to traditional fracture assessment tools.

DNA hypomethylation of Syk induces oxidative stress and apoptosis via the PKCβ/P66shc signaling pathway in diabetic kidney disease

Epigenetic alterations, especially DNA methylation, have been shown to play a role in the pathogenesis of diabetes mellitus (DM) and its complications, including diabetic kidney disease (DKD). Spleen tyrosine kinase (Syk) is known to be involved in immune and inflammatory disorders. We, therefore, investigated the possible involvement of Syk promoter methylation in DKD, and the mechanisms underlying this process. Kidney tissues were obtained from renal biopsies of patients with early and advanced DKD. A diabetic mouse model (ApoE-/- DM) was generated from ApoE knockout (ApoE-/-) mice using a high-fat and high-glucose diet combined with low-dose streptozocin intraperitoneal injection. We also established an in vitro model using HK2 cells. A marked elevation in the expression levels of Syk, PKCβ, and P66shc in renal tubules was observed in patients with DKD. In ApoE-/- DM mice, Syk expression and the binding of Sp1 to the Syk gene promoter were both increased in the kidney. In addition, the promoter region of the Syk gene exhibited hypomethylation. Syk inhibitor (R788) intervention improved renal function and alleviated pathologic changes in ApoE-/- DM mice. Moreover, R788 intervention alleviated oxidative stress and apoptosis and downregulated the expression of PKCβ/P66shc signaling pathway proteins. In HK2 cells, oxLDL combined with high-glucose stimulation upregulated Sp1 expression in the nucleus (compared with control and oxLDL groups), and this was accompanied by an increase in the binding of Sp1 to the Syk gene promoter. SP1 silencing downregulated the expression of Syk and inhibited the production of reactive oxygen species and cell apoptosis. Finally, PKC agonist intervention reversed the oxidative stress and apoptosis induced by Syk inhibitor (R406). In DKD, hypomethylation at the Syk gene promoter was accompanied by an increase in Sp1 binding at the promoter. As a consequence of this enhanced Sp1 binding, Syk gene expression was upregulated. Syk inhibitors could attenuate DKD-associated oxidative stress and apoptosis via downregulation of PKCβ/P66shc signaling pathway proteins. Together, our results identify Syk as a promising target for intervention in DKD.

Development and External Validation of Machine Learning Models for Diabetic Microvascular Complications: Cross-Sectional Study With Metabolites

BACKGROUND

Diabetic kidney disease (DKD) and diabetic retinopathy (DR) are major diabetic microvascular complications, contributing significantly to morbidity, disability, and mortality worldwide. The kidney and the eye, having similar microvascular structures and physiological and pathogenic features, may experience similar metabolic changes in diabetes.

OBJECTIVE

This study aimed to use machine learning (ML) methods integrated with metabolic data to identify biomarkers associated with DKD and DR in a multiethnic Asian population with diabetes, as well as to improve the performance of DKD and DR detection models beyond traditional risk factors.

METHODS

We used ML algorithms (logistic regression [LR] with Least Absolute Shrinkage and Selection Operator and gradient-boosting decision tree) to analyze 2772 adults with diabetes from the Singapore Epidemiology of Eye Diseases study, a population-based cross-sectional study conducted in Singapore (2004-2011). From 220 circulating metabolites and 19 risk factors, we selected the most important variables associated with DKD (defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2) and DR (defined as an Early Treatment Diabetic Retinopathy Study severity level ≥20). DKD and DR detection models were developed based on the variable selection results and externally validated on a sample of 5843 participants with diabetes from the UK biobank (2007-2010). Machine-learned model performance (area under the receiver operating characteristic curve [AUC] with 95% CI, sensitivity, and specificity) was compared to that of traditional LR adjusted for age, sex, diabetes duration, hemoglobin A1c, systolic blood pressure, and BMI.

RESULTS

Singapore Epidemiology of Eye Diseases participants had a median age of 61.7 (IQR 53.5-69.4) years, with 49.1% (1361/2772) being women, 20.2% (555/2753) having DKD, and 25.4% (685/2693) having DR. UK biobank participants had a median age of 61.0 (IQR 55.0-65.0) years, with 35.8% (2090/5843) being women, 6.7% (374/5570) having DKD, and 6.1% (355/5843) having DR. The ML algorithms identified diabetes duration, insulin usage, age, and tyrosine as the most important factors of both DKD and DR. DKD was additionally associated with cardiovascular disease history, antihypertensive medication use, and 3 metabolites (lactate, citrate, and cholesterol esters to total lipids ratio in intermediate-density lipoprotein), while DR was additionally associated with hemoglobin A1c, blood glucose, pulse pressure, and alanine. Machine-learned models for DKD and DR detection outperformed traditional LR models in both internal (AUC 0.838 vs 0.743 for DKD and 0.790 vs 0.764 for DR) and external validation (AUC 0.791 vs 0.691 for DKD and 0.778 vs 0.760 for DR).

CONCLUSIONS

This study highlighted diabetes duration, insulin usage, age, and circulating tyrosine as important factors in detecting DKD and DR. The integration of ML with biomedical big data enables biomarker discovery and improves disease detection beyond traditional risk factors.

Influence of the combination of SGLT2 inhibitors and GLP-1 receptor agonists on eGFR decline in type 2 diabetes: post-hoc analysis of RECAP study

Accumulating evidence has demonstrated that both SGLT2 inhibitors (SGLT2i) and GLP-1 receptor agonists (GLP1Ra) have protective effects in patients with diabetic kidney disease. Combination therapy with SGLT2i and GLP1Ra is commonly used in patients with type 2 diabetes (T2D). We previously reported that in combination therapy of SGLT2i and GLP1Ra, the effect on the renal composite outcome did not differ according to the preceding drug. However, it remains unclear how the initiation of combination therapy is associated with the renal function depending on the preceding drug. In this post hoc analysis, we analyzed a total of 643 T2D patients (GLP1Ra-preceding group, n = 331; SGLT2i-preceding group, n = 312) and investigated the differences in annual eGFR decline. Multiple imputation and propensity score matching were performed to compare the annual eGFR decline. The reduction in annual eGFR decline in the SGLT2i-preceding group (pre: -3.5 ± 9.4 mL/min/1.73 m2/year, post: -0.4 ± 6.3 mL/min/1.73 m2/year, p < 0.001), was significantly smaller after the initiation of GLP1Ra, whereas the GLP1Ra-preceding group tended to slow the eGFR decline but not to a statistically significant extent (pre: -2.0 ± 10.9 mL/min/1.73 m2/year, post: -1.8 ± 5.4 mL/min/1.73 m2/year, p = 0.83) after the initiation of SGLT2i. After the addition of GLP1Ra to SGLT2i-treated patients, slower annual eGFR decline was observed. Our data raise the possibility that the renal benefits-especially annual eGFR decline-of combination therapy with SGLT2i and GLP1Ra may be affected by the preceding drug.

Prognostic Value of Hemoglobin Concentration on Renal Outcomes with Diabetic Kidney Disease: A Retrospective Cohort Study

Objective

Diabetic kidney disease (DKD) patients with anemia face an elevated risk of glomerular filtration rate decline. However, the association between hemoglobin and estimated Glomerular Filtration Rate (eGFR) progression remains to be elucidated.

Methods

A retrospective cohort of 815 subjects with DKD was followed from January 2010 to January 2023. A Cox proportional hazard regression model was utilized to explore the predictive role of hemoglobin in renal outcomes. Renal outcomes were defined as a composite endpoint, including a 50% decline in eGFR from baseline or progression to End-Stage Renal Disease (ESRD). To unveil any nonlinear relationship between hemoglobin and renal outcomes, Cox proportional hazard regression with cubic spline functions and smooth curve fitting was conducted. Additionally, subgroup analyses were performed to identify specific patient populations that might derive greater benefits from higher hemoglobin.

Results

Among the 815 DKD subjects, the mean age was 56.482 ± 9.924 years old, and 533 (65.4%) were male. The mean hemoglobin was 121.521±22.960 g/L. The median follow-up time was 21.103±18.335 months. A total of 182 (22.33%) individuals reached the renal composite endpoint during the study period. After adjusting for covariates, hemoglobin was found to exert a negative impact on the renal composite endpoint in patients with DKD (HR 0.975, 95% CI [0.966, 0.984]). A nonlinear relationship between hemoglobin and the renal composite endpoint was identified with an inflection point at 109 g/L. Subgroup analysis unveiled a more pronounced association between hemoglobin and renal prognosis in males.

Conclusion

Hemoglobin emerges as a predictive indicator for the renal prognosis of diabetic kidney disease in China. This study reveals a negative and non-linear relationship between hemoglobin levels and the renal composite endpoint. A substantial association is noted when hemoglobin surpasses 109 g/L in relation to the renal composite endpoint.

Astragaloside IV attenuates renal tubule injury in DKD rats via suppression of CD36-mediated NLRP3 inflammasome activation

Background

In recent years, diabetic kidney disease (DKD) has emerged as a prominent factor contributing to end-stage renal disease. Tubulointerstitial inflammation and lipid accumulation have been identified as key factors in the development of DKD. Earlier research indicated that Astragaloside IV (AS-IV) reduces inflammation and oxidative stress, controls lipid accumulation, and provides protection to the kidneys. Nevertheless, the mechanisms responsible for its protective effects against DKD have not yet been completely elucidated.

Purpose

The primary objective of this research was to examine the protective properties of AS-IV against DKD and investigate the underlying mechanism, which involves CD36, reactive oxygen species (ROS), NLR family pyrin domain containing 3 (NLRP3), and interleukin-1β (IL-1β).

Methods

The DKD rat model was created by administering streptozotocin along with a high-fat diet. Subsequently, the DKD rats and palmitic acid (PA)-induced HK-2 cells were treated with AS-IV. Atorvastatin was used as the positive control. To assess the therapeutic effects of AS-IV on DKD, various tests including blood sugar levels, the lipid profile, renal function, and histopathological examinations were conducted. The levels of CD36, ROS, NLRP3, Caspase-1, and IL-1β were detected using western blot analysis, PCR, and flow cytometry. Furthermore, adenovirus-mediated CD36 overexpression was applied to explore the underlying mechanisms through in vitro experiments.

Results

In vivo experiments demonstrated that AS-IV significantly reduced hyperglycemia, dyslipidemia, urinary albumin excretion, and serum creatinine levels in DKD rats. Additionally, it improved renal structural abnormalities and suppressed the expression of CD36, NLRP3, IL-1β, TNF-α, and MCP-1. In vitro experiments showed that AS-IV decreased CD36 expression, lipid accumulation, and lipid ROS production while inhibiting NLRP3 activation and IL-1β secretion in PA-induced HK-2 cells.

Conclusion

AS-IV alleviated renal tubule interstitial inflammation and tubule epithelial cell apoptosis in DKD rats by inhibiting CD36-mediated lipid accumulation and NLRP3 inflammasome activation.

Association between lactate dehydrogenase and the risk of diabetic kidney disease in patients with type 2 diabetes

Objective

This study aims to investigate the association between lactate dehydrogenase (LDH) and the risk of diabetic kidney disease (DKD) in patients with type 2 diabetes (T2D).

Methods

The study enrolled patients with diagnosis of T2D between 2009 and 2018 from the National Nutrition and Health Examination Survey (NHANES) database. Demographic information, laboratory test, and diagnostic data were collected. Restricted cubic spline (RCS) plots were used to assess the dose-effect relationship between LDH levels and the risk of DKD in patients with T2D. Based on LDH levels, individuals were divided into higher and lower groups using dichotomy, and multivariate logistic regression analysis was conducted to explore the relationship between different LDH levels and the risk of DKD in T2D patients. Stratified analysis was performed to assess the consistency of the result.

Results

A total of 4888 patients were included in the study, with 2976 (60.9%) patients without DKD and 1912 (39.1%) patients with DKD. RCS plots showed that the risk of DKD increased with increasing LDH levels. Multifactorial logistic regression analysis revealed that T2D patients with higher LDH levels had a 45% increased risk of DKD compared to those with lower LDH levels (OR=1.45; 95% CI: 1.11-1.89). Furthermore, each standard deviation increase in LDH level was associated with a 24% increase in DKD incidence among T2D patients (OR=1.24; 95% CI: 1.07-1.44). Stratified analysis consistently supported these findings.

Conclusions

LDH can serve as a valuable biomarker for screening DKD in patients with T2D.

Assessing the causal relationship between gut microbiota and diabetic nephropathy: insights from two-sample Mendelian randomization

Background

The causal association between gut microbiota (GM) and the development of diabetic nephropathy (DN) remains uncertain. We sought to explore this potential association using two-sample Mendelian randomization (MR) analysis.

Methods

Genome-wide association study (GWAS) data for GM were obtained from the MiBioGen consortium. GWAS data for DN and related phenotypes were collected from the FinngenR9 and CKDGen databases. The inverse variance weighted (IVW) model was used as the primary analysis model, supplemented by various sensitivity analyses. Heterogeneity was assessed using Cochran's Q test, while horizontal pleiotropy was evaluated through MR-Egger regression and the MR-PRESSO global test. Reverse MR analysis was conducted to identify any reverse causal effects.

Results

Our analysis identified twenty-five bacterial taxa that have a causal association with DN and its related phenotypes (p < 0.05). Among them, only the g_Eubacterium_coprostanoligenes_group showed a significant causal association with type 1 DN (p < Bonferroni-adjusted p-value). Our findings remained consistent regardless of the analytical approach used, with all methods indicating the same direction of effect. No evidence of heterogeneity or horizontal pleiotropy was observed. Reverse MR analysis did not reveal any causal associations.

Conclusions

This study established a causal association between specific GM and DN. Our findings contribute to current understanding of the role of GM in the development of DN, offering potential insights for the prevention and treatment strategies for this condition.

Metabolic Profiles of Type 2 Diabetes and Their Association With Renal Complications

CONTEXT

The components of metabolic syndrome (MetS) are interrelated and associated with renal complications in patients with type 2 diabetes (T2D).

OBJECTIVE

We aimed to reveal prevalent metabolic profiles in patients with T2D and identify which metabolic profiles were risk markers for renal progression.

METHODS

A total of 3556 participants with T2D from a hospital (derivation cohort) and 931 participants with T2D from a community survey (external validation cohort) were included. The primary outcome was the onset of diabetic kidney disease (DKD), and secondary outcomes included estimated glomerular filtration rate (eGFR) decline, macroalbuminuria, and end-stage renal disease (ESRD). In the derivation cohort, clusters were identified using the 5 components of MetS, and their relationships with the outcomes were assessed. To validate the findings, participants in the validation cohort were assigned to clusters. Multivariate odds ratios (ORs) of the primary outcome were evaluated in both cohorts, adjusted for multiple covariates at baseline.

RESULTS

In the derivation cohort, 6 clusters were identified as metabolic profiles. Compared with cluster 1, cluster 3 (severe hyperglycemia) had increased risks of DKD (hazard ratio [HR] [95% CI]: 1.72 [1.39-2.12]), macroalbuminuria (2.74 [1.84-4.08]), ESRD (4.31 [1.16-15.99]), and eGFR decline [P < .001]; cluster 4 (moderate dyslipidemia) had increased risks of DKD (1.97 [1.53-2.54]) and macroalbuminuria (2.62 [1.61-4.25]). In the validation cohort, clusters 3 and 4 were replicated to have significantly increased risks of DKD (adjusted ORs: 1.24 [1.07-1.44] and 1.39 [1.03-1.87]).

CONCLUSION

We identified 6 prevalent metabolic profiles in patients with T2D. Severe hyperglycemia and moderate dyslipidemia were validated as significant risk markers for DKD.

Modification Effects of Albuminuria on the Association Between Kidney Function and Development of Anemia in Diabetes

CONTEXT

Previous studies failed to adjust for estimated glomerular filtration rate (eGFR) in evaluating the association between albuminuria and anemia development, and we aimed to investigate whether albuminuria independently affects anemia development.

METHODS

We conducted a retrospective cohort study and retrospectively identified adults with diabetes from a Japanese nationwide clinical database (JMDC, Tokyo, Japan). To assess the modification effects of albuminuria on the association between eGFR and anemia development, we estimated prevalence of anemia, defined as hemoglobin < 13 g/dL in men and < 12 g/dL in women, using a modified Poisson regression and marginal standardization form of predictive margins, stratified by albuminuria severity after adjusting for eGFR. Hence, we revealed at which eGFR level this modification effect appeared and the extent to which this modification effect increased the prevalence of anemia.

RESULTS

We identified 327 999 data points from 48 056 individuals [normoalbuminuria: 186 472 (56.9%), microalbuminuria: 107 170 (32.7%), and macroalbuminuria: 34 357 (10.5%)]. As eGFR declined, anemia prevalence increased. Albuminuria severity modified this association induced by decreased eGFR among individuals with eGFR <30 mL/min/1.73 m2 after adjusting for multivariable factors, including age, sex, comorbidities, and medication use. Compared with the normoalbuminuric group, the macroalbuminuric group had a 5% to 20% higher anemia prevalence among individuals with eGFR of <30 mL/min/1.73 m2.

CONCLUSION

We revealed that the severity of albuminuria modified the association between eGFR and anemia development among individuals with eGFR <30 mL/min/1.73 m2, highlighting the modification effect of albuminuria on the association between kidney function and anemia development in diabetes.

Rs4862705 in the melatonin receptor 1A gene is associated with renal function decline in type 1 diabetes individuals

Aim

The pathogenesis of chronic diabetes complications has oxidative stress as one of the major elements, and single-nucleotide polymorphisms (SNPs) in genes belonging to antioxidant pathways modulate susceptibility to these complications. Considering that melatonin is a powerful antioxidant compound, our aim was to explore, in a longitudinal cohort study of type 1 diabetes (T1D) individuals, the association of microvascular complications and SNPs in the gene encoding melatonin receptor 1A (MTNR1A).

Methods

Eight SNPs in MTNR1A were genotyped in 489 T1D individuals. Besides cross-sectional analyses of SNPs with each one of the microvascular complications (distal polyneuropathy, cardiovascular autonomic neuropathy, retinopathy, and diabetic kidney disease), a longitudinal analysis evaluated the associations of SNPs with renal function decline in 411 individuals followed up for a median of 8 years. In a subgroup of participants, the association of complications with urinary 6-sulfatoxymelatonin (aMT6s) concentration was investigated.

Results

The group of individuals with a renal function decline ≥ 5 mL min-1 1.73 m-2 year-1 presented a higher frequency of the A allele of rs4862705 in comparison with nondecliners, even after adjustment for confounding variables (OR = 1.84, 95% CI = 1.20-2.82; p = 0.0046). No other significant associations were found.

Conclusions

This is the first study showing an association between a variant in a gene belonging to the melatonin system and renal function decline in the diabetic setting.

Qi-dan-dihuang decoction ameliorates renal fibrosis in diabetic rats via p38MAPK/AKT/mTOR signaling pathway

CONTEXT

Qi-dan-dihuang decoction (QDD) has been used to treat diabetic kidney disease (DKD), but the underlying mechanisms are poorly understood.

OBJECTIVE

This study reveals the mechanism by which QDD ameliorates DKD.

MATERIALS AND METHODS

The compounds in QDD were identified by high-performance liquid chromatography and quadrupole-time-of-flight tandem mass spectrometry (HPLC-Q-TOF-MS). Key targets and signaling pathways were screened through bioinformatics. Nondiabetic Lepr db/m mice were used as control group, while Lepr db/db mice were divided into model group, dapagliflozin group, 1% QDD-low (QDD-L), and 2% QDD-high (QDD-H) group. After 12 weeks of administration, 24 h urinary protein, serum creatinine, and blood urea nitrogen levels were detected. Kidney tissues damage and fibrosis were evaluated by pathological staining. In addition, 30 mmol/L glucose-treated HK-2 and NRK-52E cells to induce DKD model. Cell activity and migration capacity as well as protein expression levels were evaluated.

RESULTS

A total of 46 key target genes were identified. Functional enrichment analyses showed that key target genes were significantly enriched in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) signaling pathways. In addition, in vivo and in vitro experiments confirmed that QDD ameliorated renal fibrosis in diabetic mice by resolving inflammation and inhibiting the epithelial-mesenchymal transition (EMT) via the p38MAPK and AKT-mammalian target of rapamycin (mTOR) pathways.

DISCUSSION AND CONCLUSION

QDD inhibits EMT and the inflammatory response through the p38MAPK and AKT/mTOR signaling pathways, thereby playing a protective role in renal fibrosis in DKD.

Exploring Symptom Clusters in Chinese Patients with Diabetic Kidney Disease: A Network Analysis

Purpose

The research on symptom management in patients with diabetic kidney disease (DKD) has shifted from separate symptoms to symptom clusters and networks recently. This study aimed to evaluate the unpleasant symptoms of DKD patients, and to investigate how these symptom clusters could affect patients.

Methods

408 DKD patients were recruited in this cross-sectional study. The symptoms of DKD patients were measured using the modified Dialysis Symptom Index. Network analysis was employed to evaluate the symptom network and the characteristics of individual nodes, while factor analysis was utilized to identify symptom clusters.

Results

Blurred vision was the most prevalent symptom among DKD patients. The symptoms identified as the most distressing, severe, and frequent were light headache or dizziness, arteriovenous fistula/catheterization pain, and diarrhea, respectively. Five symptom clusters were obtained from factor analysis, and the most central symptom cluster in the entire symptom network was sexual dysfunction.

Conclusion

This study identified five symptom clusters in Chinese DKD patients, with sexual dysfunction emerging as the most central cluster. These findings carry significant clinical implications, underscoring the necessity of assessing symptom clusters and their associations to enhance symptom management in DKD patients. Further research is essential to elucidate the underlying mechanisms of symptoms and to clarify the associations among symptoms in DKD patients across different disease trajectories or treatment modalities.

Intervention treatment reducing cellular senescence inhibits tubulointerstitial fibrosis in diabetic mice following acute kidney injury

Senescence of kidney tubules leads to tubulointerstitial fibrosis (TIF). Proximal tubular epithelial cells undergo stress-induced senescence during diabetes and episodes of acute kidney injury (AKI), and combining these injuries promotes the progression of diabetic kidney disease (DKD). Since TIF is crucial to progression of DKD, we examined the therapeutic potential of targeting senescence with a senolytic drug (HSP90 inhibitor) and/or a senostatic drug (ASK1 inhibitor) in a model of TIF in which AKI is superimposed on diabetes. After 8 weeks of streptozotocin-induced diabetes, mice underwent bilateral clamping of renal pedicles to induce mild AKI, followed by 28 days of reperfusion. Groups of mice (n=10-12) received either vehicle, HSP90 inhibitor (alvespimycin), ASK1 inhibitor (GS-444217), or both treatments. Vehicle-treated mice displayed tubular injury at day 3 and extensive tubular cell senescence at day 10, which remained unresolved at day 28. Markers of senescence (Cdkn1a and Cdkn2a), inflammation (Cd68, Tnf, and Ccl2), and TIF (Col1a1, Col4a3, α-Sma/Acta2, and Tgfb1) were elevated at day 28, coinciding with renal function impairment. Treatment with alvespimycin alone reduced kidney senescence and levels of Col1a1, Acta2, Tgfb1, and Cd68; however, further treatment with GS-444217 also reduced Col4a3, Tnf, Ccl2, and renal function impairment. Senolytic therapy can inhibit TIF during DKD, but its effectiveness can be improved by follow-up treatment with a senostatic inhibitor, which has important implications for treating progressive DKD.

Secretory leukocyte protease inhibitor as a novel predictive biomarker in patients with diabetic kidney disease

Background

Secretory leukocyte protease inhibitor (SLPI) is a multifunctional protein involved in the chronic inflammatory process, implicated in the pathogenesis of diabetic kidney disease (DKD). However, its potential as a diagnostic and prognostic biomarker of DKD has yet to be evaluated. This study explored the clinical utility of SLPI in the diagnosis and prognosis of renal endpoint events in patients with DKD.

Methods

A multi-center cross-sectional study comprised of 266 patients with DKD and a predictive cohort study comprised of 120 patients with stage IV DKD conducted between December 2016 and January 2022. The clinical parameters were collected for statistical analysis, a multivariate Cox proportional hazards model was used to evaluate the independent risk factors for renal endpoints.

Results

Serum SLPI levels gradually increased with DKD progression (p<0.01). A significant correlation was observed between serum SLPI levels and renal function in patients with DKD. The mean follow-up duration in this cohort study was 2.32 ± 1.30 years. Multivariate Cox regression analysis showed SLPI levels≥51.61ng/mL (HR=2.95, 95% CI[1.55, 5.60], p<0.01), 24h urinary protein levels≥3500 mg/24h (HR=3.02, 95% CI[1.66, 5.52], p<0.01), Alb levels<30g/l (HR=2.19, 95% CI[1.12, 4.28], p<0.05), HGB levels<13g/dl (HR=3.18, 95% CI[1.49, 6.80], p<0.01), and urea levels≥7.1 mmol/L (HR=8.27, 95% CI[1.96, 34.93], p<0.01) were the independent risk factors for renal endpoint events in DKD patients.

Conclusions

Serum SLPI levels increased with DKD progression and were associated with clinical parameters of DKD. Moreover, elevated SLPI levels showed potential prognostic value for renal endpoint events in individuals with DKD. These findings validate the results of previous studies on SLPI in patients with DKD and provide new insights into the role of SLPI as a biomarker for the diagnosis and prognosis of DKD that require validation.

Expression of apelin‑13 and its negative correlation with TGF‑β1 in patients with diabetic kidney disease

Diabetic kidney disease (DKD) is a severe microvascular complication of diabetes, one key feature of which includes renal fibrosis. As apelin is an adipokine closely related to diabetes, the present study aimed to evaluate apelin-13 expression levels and the relationship between apelin-13 and disease indicators in patients with diabetic kidney disease (DKD). The present case-control study enrolled 70 patients with diabetes, including 31 with diabetic kidney disease (DKD group), 39 without DKD (non-DKD group) and 30 healthy controls. The levels of serum apelin-13 and TGF-β1, the key driver of renal fibrosis, were determined by ELISA. Additionally, age, mean disease duration, weight, blood pressure, fasting blood glucose, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein, cholesterol, urea nitrogen, blood creatinine and 24-hour urinary total protein (24-h UTP) were recorded. The results demonstrated that apelin-13 and TGF-β1 expression levels, age, blood pressure, fasting blood glucose, cholesterol and blood urea nitrogen levels were significantly higher in patients with diabetes compared with the healthy controls (P<0.05). Moreover, apelin-13 and TGF-β1 expression levels, mean disease duration, systolic pressure, blood creatinine, blood urea nitrogen and 24-h UTP were significantly higher in the DKD group compared with the non-DKD group (P<0.05). The estimated glomerular filtration rate (eGFR) was significantly reduced in the DKD group compared with the non-DKD group (P<0.05). Correlation analysis demonstrated a negative correlation between apelin-13 and eGFR expression and a positive correlation between apelin-13 expression and 24-h UTP in both the DKD and non-DKD groups (P<0.05). A negative correlation was also demonstrated between apelin-13 and TGF-β1 expression levels in the DKD group and non-DKD groups (both P<0.05). In conclusion, apelin-13 and TGF-β1 expression levels were significantly higher in the DKD group compared with those in the non-DKD group. Additionally, apelin-13 expression was negatively correlated with TGF-β1 expression in the DKD and non-DKD groups. Therefore, apelin-13 could potentially be used in the future as an indicator of renal fibrosis or destruction in patients with DKD. The present trial was retrospectively registered in the Chinese Clinical Trial Registry (trial registration no. ChiCTR2200060945) on 14.06.2022.

Clinical metabolomics characteristics of diabetic kidney disease: A meta-analysis of 1875 cases with diabetic kidney disease and 4503 controls

AIMS

Diabetic Kidney Disease (DKD), one of the major complications of diabetes, is also a major cause of end-stage renal disease. Metabolomics can provide a unique metabolic profile of the disease and thus predict or diagnose the development of the disease. Therefore, this study summarises a more comprehensive set of clinical biomarkers related to DKD to identify functional metabolites significantly associated with the development of DKD and reveal their driving mechanisms for DKD.

MATERIALS AND METHODS

We searched PubMed, Embase, the Cochrane Library and Web of Science databases through October 2022. A meta-analysis was conducted on untargeted or targeted metabolomics research data based on the strategy of standardized mean differences and the process of ratio of means as the effect size, respectively. We compared the changes in metabolite levels between the DKD patients and the controls and explored the source of heterogeneity through subgroup analyses, sensitivity analysis and meta-regression analysis.

RESULTS

The 34 clinical-based metabolomics studies clarified the differential metabolites between DKD and controls, containing 4503 control subjects and 1875 patients with DKD. The results showed that a total of 60 common differential metabolites were found in both meta-analyses, of which 5 metabolites (p < 0.05) were identified as essential metabolites. Compared with the control group, metabolites glycine, aconitic acid, glycolic acid and uracil decreased significantly in DKD patients; cysteine was significantly higher. This indicates that amino acid metabolism, lipid metabolism and pyrimidine metabolism in DKD patients are disordered.

CONCLUSIONS

We have identified 5 metabolites and metabolic pathways related to DKD which can serve as biomarkers or targets for disease prevention and drug therapy.

Development of Serum Lactate Level-Based Nomograms for Predicting Diabetic Kidney Disease in Type 2 Diabetes Mellitus Patients

Purpose

To establish nomograms integrating serum lactate levels and traditional risk factors for predicting diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM) patients.

Patients and methods

A total of 570 T2DM patients and 100 healthy subjects were enrolled. T2DM patients were categorized into normal and high lactate groups. Univariate and multivariate logistic regression analyses were employed to identify independent predictors for DKD. Then, nomograms for predicting DKD were established, and the model performance was evaluated using the area under the receiver operating characteristic curve (AUC), calibration, and decision curve analysis (DCA).

Results

T2DM patients exhibited higher lactate levels compared to those in healthy subjects. Glucose, platelet, uric acid, creatinine, and hypertension were independent factors for DKD in T2DM patients with normal lactate levels, while diabetes duration, creatinine, total cholesterol, and hypertension were indicators in high lactate levels group (P<0.05). The AUC values were 0.834 (95% CI, 0.776 to 0.891) and 0.741 (95% CI, 0.688 to 0.795) for nomograms in both normal lactate and high lactate groups, respectively. The calibration curve demonstrated excellent agreement of fit. Furthermore, the DCA revealed that the threshold probability and highest Net Yield were 17-99% and 0.36, and 24-99% and 0.24 for the models in normal lactate and high lactate groups, respectively.

Conclusion

The serum lactate level-based nomogram models, combined with traditional risk factors, offer an effective tool for predicting DKD probability in T2DM patients. This approach holds promise for early risk assessment and tailored intervention strategies.

[Mechanism of ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix regulates HIF-1α signaling pathway mediated by renal hypoxia to ameliorate renal fibrosis in DKD rats]

This study explored the mechanism of the ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix in ameliorating renal fibrosis in the rat model of diabetic kidney disease(DKD) based on the expression of hypoxia-inducible factor-1α(HIF-1α)/vascular endothelial growth factor(VEGF) and HIF-1α/platelet-derived growth factor(PDGF)/platelet-derived growth factor receptor(PDGFR) signaling pathways in the DKD rats. After 1 week of adaptive feeding, 50 male SPF-grade Wistar rats were randomized into a blank group(n=7) and a modeling group. After 24 h of fasting, the rats in the modeling group were subjected to intraperitoneal injection of streptozocin and fed with a high-sugar and high-fat diet to establish a DKD model. After modeling, the rats were randomly assigned into model(n=7), low-dose ultrafiltration extract(n=7), medium-dose ultrafiltration extract(n=7), irbesartan(n=8), and high-dose ultrafiltration extract(n=8) groups. After intervention by corresponding drugs for 12 weeks, the general conditions of the rats were observed. The body weights and blood glucose levels of the rats were measured weekly, and the 24 h urinary protein(24hUP) was measured at the 6th and 12th weeks of drug administration. After the last drug administration, the renal function indicators were determined. Masson staining was employed to observe the pathological changes of the renal tissue. The expression of prolyl hydroxylase domain 2(PHD2) and HIF-1α in the renal tissue was detected by immunohistochemistry(IHC). Real-time qPCR was employed to determine the mRNA levels of PHD2, VEGF, PDGF, and PDGFR in the renal tissue. Western blot was employed to determine the protein levels of HIF-1α, VEGF, PDGF, and PDGFR in the renal tissue. The results showed that compared with the model group, drug administration lowered the levels of glycosylated serum protein(GSP), aerum creatinine(Scr), and blood urea nitrogen(BUN) in a dose-dependent manner(P<0.05 or P<0.01) and mitigated the pathological changes in the renal tissue. Furthermore, drug administration up-regulated mRNA level of PHD2(P<0.05 or P<0.01), down-regulated the mRNA levels of VEGF, PDGF, and PDGFR(P<0.05 or P<0.01) and the protein levels of HIF-1α, VEGF, PDGF, and PDGFR(P<0.01) in the renal tissue, and increased the rate of PHD2-positive cells(P<0.01). In conclusion, the ultrafiltration extract of Angelicae Sinensis Radix and Hedysari Radix effectively alleviated the renal fibrosis in DKD rats by inhibiting the expression of key proteins in the HIF-1α signaling pathway mediated by renal hypoxia and reducing extracellular matrix(ECM) deposition.

Senolytic combination of dasatinib and quercetin protects against diabetic kidney disease by activating autophagy to alleviate podocyte dedifferentiation via the Notch pathway

The senolytics dasatinib and quercetin (DQ) alleviate age‑related disorders. However, limited information is available regarding the effects of DQ on diabetic kidney disease (DKD). The present study aimed to explore the effects of DQ on DKD and its potential molecular mechanism(s). Dasatinib (5 mg/kg) and quercetin (50 mg/kg) were administered to diabetic db/db mice by gavage for 20 weeks. Body weight, urine albumin‑creatinine ratio (ACR), serum creatinine (Scr), and blood urea nitrogen (BUN) were recorded at the indicated time periods. Periodic acid‑Schiff and Masson's staining were performed to assess the histopathological changes of kidney tissues. Immunohistochemical analysis, immunofluorescence and western blotting were performed to evaluate the expression levels of extracellular matrix (ECM) proteins, autophagic and podocyte differentiation‑related proteins. In addition, mouse podocytes were administered with high‑glucose, DQ and 3‑methyladenine (3‑MA), and the expression levels of autophagic and podocyte differentiation‑related proteins were measured. Moreover, following overexpression of the Notch intracellular domain (NICD), the expression levels of NICD, autophagic and podocyte differentiation‑related proteins were further assessed. DQ significantly reduced the body weight, blood glucose, ACR, Scr and BUN levels and improved the histopathological changes induced in diabetic db/db mice. In addition, DQ caused a significant downregulation of the expression levels of the ECM proteins, improved autophagy and induced an upregulation of the expression levels of podocyte differentiation‑related proteins. Administration of 3‑MA to mice significantly reduced podocyte differentiation, and overexpression of NICD could reverse the effects of DQ on autophagy and podocyte differentiation in vitro. The present study suggests that DQ protects against DKD by activation of autophagy to alleviate podocyte dedifferentiation via the Notch pathway.

Macrophage polarization and signaling in diabetic kidney disease: a catalyst for disease progression

Diabetic kidney disease (DKD) is a serious complication of diabetes affecting millions of people worldwide. Macrophages, a critical immune cell type, are central players in the development and progression of DKD. In this comprehensive review, we delve into the intricate role of macrophages in DKD, examining how they can become polarized into proinflammatory M1 or anti-inflammatory M2 phenotypes. We explore the signaling pathways involved in macrophage recruitment and polarization in the kidneys, including the key cytokines and transcription factors that promote M1 and M2 polarization. In addition, we discuss the latest clinical studies investigating macrophages in DKD and explore the potential of hypoglycemic drugs for modulating macrophage polarization. By gaining a deeper understanding of the mechanisms that regulate macrophage polarization in DKD, we may identify novel therapeutic targets for this debilitating complication of diabetes. This review provides valuable insights into the complex interplay between macrophages and DKD, shedding light on the latest developments in this important area of research. This review aims to enhance understanding of the role that macrophages play in the pathogenesis of DKD.

[Evaluation of chemical constituents of Draconis Sanguis and its protective effect on renal tubular injury in diabetic kidney disease]

The chemical constituents of Draconis Sanguis were preliminarily studied by macroporous resin, silica gel, dextran gel, and high-performance liquid chromatography. One retro-dihydrochalcone, four flavonoids, and one stilbene were isolated. Their chemical structures were identified as 4-hydroxy-2,6-dimethoxy-3-methyldihydrochalcone(1), 4'-hydroxy-5,7-dimethoxy-8-methylflavan(2), 7-hydroxy-4',5-dimethoxyflavan(3),(2S)-7-hydroxy-5-methoxy-6-methylflavan(4),(2S)-7-hydroxy-5-methoxyflavan(5), and pterostilbene(6) by modern spectroscopy, physicochemical properties, and literature comparison. Compound 1 was a new compound. Compounds 2 and 6 were first found in the Arecaceae family. Compound 5 had the potential to prevent and treat diabetic kidney disease.

Efficacy of adipose-derived mesenchymal stem cell therapy in the treatment of chronic micro- and macrovascular complications of diabetes

Diabetes mellitus is a highly prevalent disease characterized by hyperglycaemia that damages the vascular system, leading to micro- (retinopathy, neuropathy, nephropathy) and macrovascular diseases (cardiovascular disease). There are also secondary complications of diabetes (cardiomyopathy, erectile dysfunction or diabetic foot ulcers). Stem cell-based therapies have become a promising tool targeting diabetes symptoms and its chronic complications. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are of great importance because of their abundance, non-invasive isolation and no ethical limitations. Characteristics that make ADMSCs good candidates for cell-based therapy are their wide immunomodulatory properties and paracrine activities through the secretion of an array of growth factors, chemokines, cytokines, angiogenic factors and anti-apoptotic molecules. Besides, after transplantation, ADMSCs show great ex vivo expansion capacity and differentiation to other cell types, including insulin-producing cells, cardiomyocytes, chondrocytes, hepatocyte-like cells, neurons, endothelial cells, photoreceptor-like cells, or astrocytes. Preclinical studies have shown that ADMSC-based therapy effectively improved visual acuity, ameliorated polyneuropathy and foot ulceration, arrested the development and progression of diabetic kidney disease, or alleviated the diabetes-induced cardiomyocyte hypertrophy. However, despite the positive results obtained in animal models, there are still several challenges that need to be overcome before the results of preclinical studies can be translated into clinical applications. To date, there are several clinical trials or ongoing trials using ADMSCs in the treatment of diabetic complications, most of them in the treatment of diabetic foot ulcers. This narrative review summarizes the most recent outcomes on the usage of ADMSCs in the treatment of long-term complications of diabetes in both animal models and clinical trials.

Dapagliflozin Alleviates Diabetic Kidney Disease via Hypoxia Inducible Factor 1α/Heme Oxygenase 1-Mediated Ferroptosis

Aims: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) showed excellent renoprotective effects; however, the underlying mechanism remains not fully understood. Previous studies have revealed the importance of ferroptosis, which is closely related to oxidative stress, in the progression of DKD. In the current study, we hypothesized that SGLT2i could relieve ferroptosis and thereby alleviate renal injury in DKD due to their antioxidative stress effects. Results: Typical changes of ferroptosis including massive lipid peroxidation, compromised antioxidant capability, and iron overload were found in db/db mice and high glucose/high fat (HG/HF)-treated HK-2 cells. Furthermore, increased expression of hypoxia inducible factor 1α (HIF1α) and heme oxygenase 1 (HO1) was observed in db/db mice and HG/HF-treated HK-2 cells as well. Dapagliflozin treatment significantly ameliorated the ferroptosis-related changes via attenuating overactivation of the HIF1α/HO1 axis in vivo and in vitro. Besides, downregulation of the HIF1α/HO1 axis alleviated ferroptosis, while overexpression of HIF1α and HO1 aggravated ferroptosis induced by HG/HF in HK-2 cells. Innovation and Conclusion: This study revealed that SGLT2i played a renoprotective role in DKD, at least in part, through alleviating HIF1α/HO1-mediated ferroptosis. Antioxid. Redox Signal. 40, 492-509.

The effect of primary renal disease upon outcomes after renal transplant

BACKGROUND

This study investigated whether nature of primary renal disease affects clinical outcomes after renal transplantation at a single center in the United Kingdom.

METHODS

This was a retrospective cohort study of 961 renal transplant recipients followed up at a large renal center from 2000 to 2020. Separation of diseases responsible for end-stage kidney disease included glomerulonephritis, diabetic kidney disease, hypertensive nephropathy, autosomal dominant polycystic kidney disease, unknown cause, other causes and chronic pyelonephritis. Outcome data included graft loss, cardiovascular events, malignancy, post-transplant diabetes mellitus and death, analyzed according to primary disease type.

RESULTS

The mean age at transplantation was 47.3 years. During a mean follow-up of 7.6 years, 18% of the overall cohort died corresponding to an annualised mortality rate of 2.3%. Death with a functioning graft occurred at a rate of 2.1% per annum, with the highest incidence observed in in patients with diabetic kidney disease (4.1%/year). Post-transplant cardiovascular events occurred in 21% of recipients (2.8% per year), again highest in recipients with diabetic kidney disease (5.1%/year) and hypertensive nephropathy (4.5%/year). Post-transplant diabetes mellitus manifested in 19% of the cohort at an annualized rate of2.1% while cancer incidence stood at 9% with an annualized rate of 1.1% . Graft loss occurred in 6.8% of recipients at the rate of1.2% per year with chronic allograft injury, acute rejection and recurrent glomerulonephritis being the predominant causative factors. Median + IQR dialysis-free survival of the whole cohort was 16.2 (9.9 - > 20) years, being shortest for diabetic kidney disease (11.0 years) and greatest for autosomal dominant polycystic kidney disease (18.2 years) .The collective mean decline in eGFR over time was -1.14ml/min/year. Recipients with Pre-transplant diabetic kidney disease exhibited the fastest rate of decline(-2.1ml/min/year) a statistically significant difference in comparison to the other native kidney diseases with Autosomal dominant polycystic kidney disease exhibiting the lowest rate of decline(-0.05ml/min/year) CONCLUSION: Primary renal disease can influence the outcome after renal transplantation, with patients with prior diabetic kidney disease having the poorest outcome in terms of dialysis-free survival and loss of transplant function. Autosomal polycystic kidney disease, other cause and unknown cause had the best outcomes compared to other primary renal disease groups.

New insights into the role of immunity and inflammation in diabetic kidney disease in the omics era

Diabetic kidney disease (DKD) is becoming the leading cause of chronic kidney disease, especially in the industrialized world. Despite mounting evidence has demonstrated that immunity and inflammation are highly involved in the pathogenesis and progression of DKD, the underlying mechanisms remain incompletely understood. Substantial molecules, signaling pathways, and cell types participate in DKD inflammation, by integrating into a complex regulatory network. Most of the studies have focused on individual components, without presenting their importance in the global or system-based processes, which largely hinders clinical translation. Besides, conventional technologies failed to monitor the different behaviors of resident renal cells and immune cells, making it difficult to understand their contributions to inflammation in DKD. Recently, the advancement of omics technologies including genomics, epigenomics, transcriptomics, proteomics, and metabolomics has revolutionized biomedical research, which allows an unbiased global analysis of changes in DNA, RNA, proteins, and metabolites in disease settings, even at single-cell and spatial resolutions. They help us to identify critical regulators of inflammation processes and provide an overview of cell heterogeneity in DKD. This review aims to summarize the application of multiple omics in the field of DKD and emphasize the latest evidence on the interplay of inflammation and DKD revealed by these technologies, which will provide new insights into the role of inflammation in the pathogenesis of DKD and lead to the development of novel therapeutic approaches and diagnostic biomarkers.

Exogenous hydrogen sulfide prevents SOD2 degradation to safeguard renal function in diabetic kidney disease

Diabetic kidney disease (DKD) is a major contributor to chronic kidney disease. Hydrogen sulfide (H2S) serves as an endogenous gaseous signaling molecule capable of safeguarding renal function within the context of DKD. However, the underlying mechanisms need to be elucidated. This study was undertaken to unveil the mechanisms by which H2S counteracts against DKD. Utilizing mice and human renal tubular epithelial (HK-2) cells, we demonstrated a reduction in cystathionine-γ-lyase/H2S levels within renal tissues of db/db mice and in HK-2 cells subjected to hyperglycemic and hyperlipidemic environments. Notably, we observed that sodium hydrosulfide (NaHS) supplementation could serve as an exogenous source of H2S. Exogenous H2S exhibited the capacity to mitigate the accumulation of reactive oxygen species and attenuate the degradation of superoxide dismutase 2 (SOD2) by Lon protease homolog 1 induced by hyperglycemia and hyperlipidemia, thus affording cellular protection against mitochondrial apoptosis. Consequently, NaHS treatment led to decreased serum levels of blood urea nitrogen and serum creatinine, reflecting alleviated renal damage and thereby preserving renal function in db/db mice. Based on these findings, we propose that exogenous H2S exerts a protective role against DKD by inhibiting SOD2 degradation.

Serum high mobility group box 1 as a potential biomarker for the progression of kidney disease in patients with type 2 diabetes

Background

As a damage-associated molecular pattern protein, high mobility group box 1 (HMGB1) is associated with kidney and systemic inflammation. The predictive and therapeutic value of HMGB1 as a biomarker has been confirmed in various diseases. However, its value in diabetic kidney disease (DKD) remains unclear. Therefore, this study aimed to investigate the correlation between serum and urine HMGB1 levels and DKD progression.

Methods

We recruited 196 patients with type 2 diabetes mellitus (T2DM), including 109 with DKD and 87 T2DM patients without DKD. Additionally, 60 healthy participants without T2DM were also recruited as controls. Serum and urine samples were collected for HMGB1 analysis. Simultaneously, tumor necrosis factor receptor superfamily member 1A (TNFR-1) in serum and kidney injury molecule (KIM-1) in urine samples were evaluated for comparison.

Results

Serum and urine HMGB1 levels were significantly higher in patients with DKD than in patients with T2DM and healthy controls. Additionally, serum HMGB1 levels significantly and positively correlated with serum TNFR-1 (R 2 = 0.567, p<0.001) and urine KIM-1 levels (R 2 = 0.440, p<0.001), and urine HMGB1 has a similar correlation. In the population with T2DM, the risk of DKD progression increased with an increase in serum HMGB1 levels. Multivariate logistic regression analysis showed that elevated serum HMGB1 level was an independent risk factor for renal function progression in patients with DKD, and regression analysis did not change in the model corrected for multiple variables. The restricted cubic spline depicted a nonlinear relationship between serum HMGB1 and renal function progression in patients with DKD (p-nonlinear=0.007, p<0.001), and this positive effect remained consistent across subgroups.

Conclusion

Serum HMGB1 was significantly correlated with DKD and disease severity. When the HMGB1 level was ≥27 ng/ml, the risk of renal progression increased sharply, indicating that serum HMGB1 can be used as a potential biomarker for the diagnosis of DKD progression.

Low Levels of Metrnl are Linked to the Deterioration of Diabetic Kidney Disease

Objective

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Metrnl is a secreted protein that plays an important role in kidney disease. The aim of this study was to investigate DKD-related factors and the correlation between serum Metrnl levels and the severity of DKD.

Methods

Ninety-six type 2 diabetes mellitus (T2DM) patients and 45 DKD patients were included in the study. A range of parameters were measured simultaneously, including waist-to-hip ratio (WHR), body mass index (BMI), urinary albumin/creatinine ratio (UACR), monocyte-lymphocyte ratio (MLR), albumin/globulin (A/G), liver and kidney function, blood lipid profile, islet function, and others. Subsequently, the related factors and predictive significance of DKD were identified. The correlation between the relevant factors of DKD and serum Metrnl levels with DKD was evaluated.

Results

The duration of the disease (OR: 1.12, 95% CI: 1.01-1.24, P=0.031), hypertension (OR: 4.86, 95% CI: 1.16-20.49, P=0.031), fasting blood glucose (OR: 1.23, 95% CI: 1.03-1.48, P=0.025), WHR (OR: 2.53, 95% CI: 1.03-6.22, P=0.044), and MLR (OR: 1.91, 95% CI: 1.18-3.08, P=0.008) are independent risk factors for DKD (P < 0.05). Conversely, A/G (OR: 0.13, 95% CI: 0.02-0.76, P=0.024) and Metrnl (OR: 0.99, 95% CI: 0.98-1.00, P=0.001) have been identified as protective factors against DKD. Furthermore, the level of Metrnl was negatively correlated with the severity of DKD (rs=-0.447, P<0.001). The area under receiver operating characteristic (ROC) curves for the diagnostic accuracy of Metrnl for DKD is 0.765 (95% CI: 0.686-0.844).

Conclusion

The duration of the disease, hypertension, fasting blood glucose, WHR, and MLR are major risk factors for DKD. Metrnl and A/G are protective factors for DKD. Serum Metrnl concentrations are inversely correlated with DKD severity.

A strategic study of acupuncture for diabetic kidney disease based on meta-analysis and data mining

Objective

The specific benefit and selection of acupoints in acupuncture for diabetic kidney disease (DKD) remains controversial. This study aims to explore the specific benefits and acupoints selection of acupuncture for DKD through meta-analysis and data mining.

Methods

Clinical trials of acupuncture for DKD were searched in eight common databases. Meta-analysis was used to evaluate its efficacy and safety, and data mining was used to explore its acupoints selection.

Results

Meta-analysis displayed that compared with the conventional drug group, the combined acupuncture group significantly increased the clinical effective rate (risk ratio [RR] 1.35, 95% confidence interval [CI] 1.20 to 1.51, P < 0.00001) and high-density lipoprotein cholesterol (mean difference [MD] 0.36, 95% CI 0.27 to 0.46, P < 0.00001), significantly reduced the urinary albumin (MD -0.39, 95% CI -0.42 to -0.36, P < 0.00001), urinary microalbumin (MD -32.63, 95% CI -42.47 to -22.79, P < 0.00001), urine β2-microglobulin (MD -0.45, 95% CI -0.66 to -0.24, P < 0.0001), serum creatinine (MD -15.36, 95% CI -21.69 to -9.03, P < 0.00001), glycated hemoglobin A1c (MD -0.69, 95% CI -1.18 to -0.19, P = 0.006), fasting blood glucose (MD -0.86, 95% CI -0.90 to -0.82, P < 0.00001), 2h postprandial plasma glucose (MD -0.87, 95% CI -0.92 to -0.82, P < 0.00001), total cholesterol (MD -1.23, 95% CI -2.05 to -0.40, P = 0.003), triglyceride (MD -0.69, 95% CI -1.23 to -0.15, P = 0.01), while adverse events were comparable. Data mining revealed that CV12, SP8, SP10, ST36, SP6, BL20, BL23, and SP9 were the core acupoints for DKD treated by acupuncture.

Conclusion

Acupuncture improved clinical symptoms, renal function indices such as uALB, umALB, uβ2-MG, and SCR, as well as blood glucose and blood lipid in patients with DKD, and has a favorable safety profile. CV12, SP8, SP10, ST36, SP6, BL20, BL23, and SP9 are the core acupoints for acupuncture in DKD, and this program is expected to become a supplementary treatment for DKD.

GSK3β: A ray of hope for the treatment of diabetic kidney disease

Diabetic kidney disease (DKD), a major microvascular complication of diabetes, is characterized by its complex pathogenesis, high risk of chronic renal failure, and lack of effective diagnosis and treatment methods. GSK3β (glycogen synthase kinase 3β), a highly conserved threonine/serine kinase, was found to activate glycogen synthase. As a key molecule of the glucose metabolism pathway, GSK3β participates in a variety of cellular activities and plays a pivotal role in multiple diseases. However, these effects are not only mediated by affecting glucose metabolism. This review elaborates on the role of GSK3β in DKD and its damage mechanism in different intrinsic renal cells. GSK3β is also a biomarker indicating the progression of DKD. Finally, the protective effects of GSK3β inhibitors on DKD are also discussed.

Insights into serum metabolic biomarkers for early detection of incident diabetic kidney disease in Chinese patients with type 2 diabetes by random forest

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease (ESRD) worldwide. Early detection is critical for the risk stratification and early intervention of progressive DKD. Serum creatinine (sCr) and urine output are used to assess kidney function, but these markers are limited by their delayed changes following kidney pathology, and lacking of both sensitivity and accuracy. Hence, it is essential to illustrate potential diagnostic indicators to enhance the precise prediction of early DKD. A total of 194 Chinese individuals include 30 healthy participants (Stage 0) and 164 incidents with type 2 diabetes (T2D) spanning from DKD's Stage 1a to 4 were recruited and their serums were subjected for untargeted metabolomic analysis. Random forest (RF), a machine learning approach, together with univariate linear regression (ULR) and multivariate linear regression (MvLR) analysis were applied to characterize the features of untargeted metabolites of DKD patients and to identify candidate DKD biomarkers. Our results indicate that 2-(α-D-mannopyranosyl)-L-tryptophan (ADT), succinyladenosine (SAdo), pseudouridine and N,N,N-trimethyl-L-alanyl-L-proline betaine (L-L-TMAP) were associated with the development of DKD, in particular, the latter three that were significantly elevated in Stage 2-4 T2D incidents. Each of the four metabolites in combination with sCr achieves better performance than sCr alone with area under the receiver operating characteristic curve (AUC) of 0.81-0.91 in predicting DKD stages. An average of 3.9 years follow-up study of another cohort including 106 Stage 2-3 patients suggested that "urinary albumin-to-creatinine ratio (UACR) + ADT + SAdo" can be utilized for better prognosis evaluation of early DKD (average AUC = 0.9502) than UACR without sexual difference.

A meta-analysis of urinary transferrin for early diagnosis of diabetic nephropathy

OBJECTIVE

To assess the diagnostic value of urinary transferrin (Tf) in early diabetic nephropathy (DN) to propose a more sensitive and noninvasive biomarker for screening and monitoring DN in clinical practice.

METHODS

We searched 3 databases from their inception to May 2023, to identify studies investigating the diagnostic value of Tf in patients with DN. Meta-DiSc software, version 1.4, and Stata software, version 15.1 (StataCorp) were used to conduct a meta-analysis and evaluate the diagnostic accuracy of urine Tf levels for DN.

RESULTS

The meta-analysis included 6 relevant studies investigating the diagnostic value of Tf level for DN. Urinary Tf as a diagnostic marker demonstrated a combined sensitivity of 0.82 (95% CI, 0.71-0.89) and specificity of 0.88 (0.84-0.92). the positive diagnostic likelihood ratio was 7.07 (4.57-10.93), the negative diagnostic likelihood ratio was 0.20 (0.12-0.35), and the diagnostic odds ratio was 34.49 (13.61-87.44). Also, the area under the receiver operating characteristic curve was 0.92 (0.89-0.94), indicating that urinary Tf has a decent discriminative ability in diagnosing DN.

CONCLUSION

Tf level is a valuable biological marker for early diagnosis and monitoring of DN in clinical practice. It has statistically significant predictive value for patients in the early phases of DN.

Oral Chinese Herbal Medicine plus usual care for diabetic kidney disease: study protocol for a randomized, double-blind, placebo-controlled pilot trial

Background

Diabetic kidney disease (DKD) has become the leading cause of kidney failure, causing a significant socioeconomic burden worldwide. The usual care for DKD fails to achieve satisfactory effects in delaying the persistent loss of renal function. A Chinese herbal medicine, Tangshen Qushi Formula (TQF), showed preliminary clinical benefits with a sound safety profile for people with stage 2-4 DKD. We present the protocol of an ongoing clinical trial investigating the feasibility, efficacy, and safety of TQF compared to placebo in delaying the progressive decline of renal function for people with stage 2-4 DKD.

Methods

A mixed methods research design will be used in this study. A randomized, double-blind, placebo-controlled pilot trial will evaluate the feasibility, efficacy, and safety of TQF compared to placebo on kidney function for people with stage 2-4 DKD. An embedded semi-structured interview will explore the acceptability of TQF granules and trial procedures from the participant's perspective. Sixty eligible participants with stage 2-4 DKD will be randomly allocated to the treatment group (TQF plus usual care) or the control group (TQF placebo plus usual care) at a 1:1 ratio for 48-week treatment and 12-week follow-up. Participants will be assessed every 12 weeks. The feasibility will be assessed as the primary outcome. The changes in the estimated glomerular filtration rate, urinary protein/albumin, renal function, glycemic and lipid markers, renal composite endpoint events, and dampness syndrome of Chinese medicine will be assessed as the efficacy outcomes. Safety outcomes such as liver function, serum potassium, and adverse events will also be evaluated. The data and safety monitoring board will be responsible for the participants' benefits, the data's credibility, and the results' validity. The intent-to-treat and per-protocol analysis will be performed as the primary statistical strategy.

Discussion

Conducting a rigorously designed pilot trial will be a significant step toward establishing the feasibility and acceptability of TQF and trial design. The study will also provide critical information for future full-scale trial design to further generate new evidence supporting clinical practice for people with stage 2-4 DKD.

Trial registration number

https://www.chictr.org.cn/, identifier ChiCTR2200062786.