Diabetic kidney disease: A systematic review on the role of epigenetics as diagnostic and prognostic marker

Advancements in diabetic kidney disease management: integrating innovative therapies and targeted drug development

Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease and affects approximately 40% of individuals with diabetes . Cases of DKD continue to rise globally as the prevalence of diabetes mellitus increases, with an estimated 415 million people living with diabetes in 2015 and a projected 642 million by 2040. DKD is associated with significant morbidity and mortality, representing 34% and 36% of all chronic kidney disease deaths in men and women, respectively. Common comorbidities including hypertension and ageing-related nephron loss further complicate disease diagnosis and progression. The progression of DKD involves several mechanisms including glomerular endothelial cell dysfunction, inflammation, and fibrosis. Targeting these mechanisms has formed the basis of several therapeutic agents. Renin-angiotensin-aldosterone system (RAAS) blockers, specifically angiotensin receptor blockers (ARBs), demonstrate significant reductions in macroalbuminuria. Sodium-glucose transporter type 2 (SGLT-2) inhibitors demonstrate kidney protection independent of diabetes control while also decreasing the incidence of cardiovascular events. Emerging agents including glucagon-like peptide 1 (GLP-1) agonists, anti-inflammatory agents like bardoxolone, and mineralocorticoid receptor antagonists show promise in mitigating DKD progression. Many novel therapies including monoclonal antibodies CSL346, lixudebart, and tozorakimab; mesenchymal stem/stromal cell infusion; and cannabinoid-1 receptor inverse agonism via INV-202 are currently in clinical trials and present opportunities for further drug development.

The role of long non-coding RNAs in the development of diabetic kidney disease and the involved clinical application

Diabetic kidney disease (DKD), one of the common microvascular complications of diabetes, is increasing in prevalence worldwide and can lead to End-stage renal disease. However, there are still gaps in our understanding of the pathophysiology of DKD, and both current clinical diagnostic methods and treatment strategies have drawbacks. According to recent research, long non-coding RNAs (lncRNAs) are intimately linked to the developmental process of DKD and could be viable targets for clinical diagnostic decisions and therapeutic interventions. Here, we review recent insights gained into lncRNAs in pathological changes of DKD such as mesangial expansion, podocyte injury, renal tubular injury, and interstitial fibrosis. We also discuss the clinical applications of DKD-associated lncRNAs as diagnostic biomarkers and therapeutic targets, as well as their limitations and challenges, to provide new methods for the prevention, diagnosis, and treatment of DKD.

Environmental Factors and the Risk of Developing Type 1 Diabetes-Old Disease and New Data

Simple Summary

Despite many studies, the risk factors of type 1 diabetes (T1DM) in children and adolescents are still not fully understood and remain a big challenge. Therefore, an extensive online search for scientific research on factors related to diabetes has been performed for the identification of new factors of unexplained etiology. A better understanding of the role of viral, bacterial, and yeast-like fungi infections related to the risk of T1DM in children and adolescents and the identification of new risk factors, especially those spread by the droplet route, is of great importance for people and families with diabetes.

Abstract

The incidence of type 1 diabetes (T1D) is increasing worldwide. The onset of T1D usually occurs in childhood and is caused by the selective destruction of insulin-producing pancreatic islet cells (β-cells) by autoreactive T cells, leading to insulin deficiency. Despite advanced research and enormous progress in medicine, the causes of T1D are still not fully understood. Therefore, an extensive online search for scientific research on environmental factors associated with diabetes and the identification of new factors of unexplained etiology has been carried out using the PubMed, Cochrane, and Embase databases. The search results were limited to the past 11 years of research and discovered 143 manuscripts published between 2011 and 2022. Additionally, 21 manuscripts from between 2000 and 2010 and 3 manuscripts from 1974 to 2000 were referenced for historical reference as the first studies showcasing a certain phenomenon or mechanism. More and more scientists are inclined to believe that environmental factors are responsible for the increased incidence of diabetes. Research results show that higher T1D incidence is associated with vitamin D deficiency, a colder climate, and pollution of the environment, as well as the influence of viral, bacterial, and yeast-like fungi infections. The key viral infections affecting the risk of developing T1DM are rubella virus, mumps virus, Coxsackie virus, cytomegalovirus, and enterovirus. Since 2020, i.e., from the beginning of the COVID-19 pandemic, more and more studies have been looking for a link between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and diabetes development. A better understanding of the role of viral, bacterial, and yeast-like fungi infections related to the risk of T1DM in children and adolescents and the identification of new risk factors, especially those spread by the droplet route, is of great importance for people and families with diabetes.

The association between serum interleukin-1 beta and heparin sulphate in diabetic nephropathy patients

Inflammation is considered an important mechanism in the development of diabetes mellitus (DM) and persists for a long time before the occurrence of diabetic nephropathy (DN). Many studies have demonstrated that a decrease in the endothelial glycocalyx (EG) is negatively correlated with proteinuria. To elucidate whether EG damage induced by inflammasomes in DM patients leads to the occurrence of microalbuminuria (MA) and accelerates the progression of DN, this study screened 300 diagnosed DM patients. Finally, 70 type 2 diabetes patients were invited to participate in this study and were divided into two groups: the T2DM group (patients with normal MA and without diabetic retinopathy, n = 35) and the T2DN group (patients with increased MA and diabetic retinopathy, n = 35). Circulating heparin sulphate (HS, EG biomarkers) and interleukin-1 beta (IL-1β, inflammasome biomarkers) of the patients were measured by ELISA. Laboratory data were measured using routine laboratory methods. Patients in the T2DN group had increased serum HS, increased IL-1β, increased CRP, decreased haemoglobin, and increased neutrophils compared to patients in the T2DM group (all P < 0.05). Increased HS and decreased haemoglobin were independently associated with T2DN patients. ROC curves showed that the AUC of HS for the prediction of T2DN was 0.67 (P < 0.05). The combination of HS and haemoglobin yielded a significant increasement in the AUC (0.75, P < 0.001) with optimal sensitivity (71.2%) and specificity (79%). Furthermore, serum IL-1β was positively correlated with HS and was an independent associated factor of HS in the T2DN group. The relationship between HS and IL-1β was not significant in the T2DM group. Our findings surgessed the inflammasome may be associated with and promote damage to the EG during the disease course of DN that manifests as increased MA.

Compositional Alterations of Gut Microbiota in Patients with Diabetic Kidney Disease and Type 2 Diabetes Mellitus

PURPOSE

Emerging evidence has revealed that gut microbiota plays a pivotal role in the pathogenesis of type 2 diabetes mellitus (T₂DM) and diabetic kidney disease (DKD). However, few studies have used metagenomic sequencing to analyze the alterations of gut microbiota community in patients with early-stage DKD.

METHODS

We carried out metagenomic sequencing in fecal samples of 10 DKD patients (DKD group) and 10 T₂DM patients who appeared to be less prone to DKD (non-DKD group), aiming to compare the composition and function of gut microbiota between the DKD and non-DKD groups.

RESULTS

The gut microbial community of the DKD group was significantly different from that of the non-DKD group, characterized by a marked increase in phylum Proteobacteria, genus Selenomonadales, Neosynechococcus, Shigella, Bilophila, Acidaminococcus, species, Escherichia coli, Bacteroides plebeius, Megasphaera elsdenii, Acidaminococcus unclassified, and Bilophila wadsworthia. The amounts of species Citrobacter farmeri and Syntrophaceticus schinkii were significantly and positively correlated with the urinary albumin creatinine ratio in the DKD group. Furthermore, functional analysis based on dbCAN and KEGG databases showed aberrant lipopolysaccharide (LPS) biosynthesis and carbohydrate metabolism in the gut microbiome of the DKD group.

CONCLUSION

Our findings provided evidence for alterations in the composition and function of gut microbiota in patients with DKD versus the non-DKD group. These data may contribute to a more comprehensive understanding of the pathological mechanisms of DKD.

Epidermal Growth Factor Protects Against High Glucose-Induced Podocyte Injury Possibly via Modulation of Autophagy and PI3K/AKT/mTOR Signaling Pathway Through DNA Methylation

AIM

Diabetic nephropathy (DN) is a serious health problem worldwide. Epidermal growth factor (EGF) has suggested as a potential biomarker for the progression of chronic kidney disease. In this study, we examined the effects of EGF on the high glucose (HG)-induced podocyte injury and explored the underlying molecular mechanisms.

METHODS

The cell proliferation, toxicity, and cell apoptosis of podocytes were determined by CCK-8 assay, lactate dehydrogenase release assay, and flow cytometry, respectively, and protein levels in the podocytes were determined by Western blot assay. Mechanistically, DNA methylation analysis, bioinformatic analysis, methylation‑specific PCR and quantitative real-time PCR were used to analyze functional pathways in differentially methylated genes and the expression of the key methylated genes in the podocytes after different interventions.

RESULTS

EGF treatment significantly increased the protein expression level of LC3 and decreased the protein level of P62 in HG-stimulated podocytes, which was attenuated by autophagy inhibitor, 3-methyladenine. EGF increased the cell proliferation and the protein expression levels of nephrin and synaptopodin, but reduced cell toxicity and cell apoptosis and protein expression level of cleaved caspase-3, which was partially antagonized by 3-methyladenine. DNA methylation expression profiles revealed the differential hypermethylation sites and hypomethylation sites among podocytes treated with normal glucose, HG and HG+EGF. GO enrichment analysis showed that DNA methylation was significantly enriched in negative regulation of phosphorylation, cell-cell junction and GTPase binding. KEGG pathway analysis showed that these genes were mainly enriched in PI3K-Akt, Hippo and autophagy pathways. Further validation studies revealed that six hub genes (ITGB1, GRB2, FN1, ITGB3, FZD10 and FGFR1) may be associated with the protective effects of EGF on the HG-induced podocyte injury.

CONCLUSION

In summary, our results demonstrated that EGF exerted protective effects on HG-induced podocytes injury via enhancing cell proliferation and inhibiting cell apoptosis. Further mechanistic studies implied that EGF-mediated protective effects in HG-stimulated podocytes may be associated with modulation of autophagy and PI3K/AKT/mTOR signaling pathway.

Identification of C3 as a therapeutic target for diabetic nephropathy by bioinformatics analysis

The pathogenesis of diabetic nephropathy is not completely understood, and the effects of existing treatments are not satisfactory. Various public platforms already contain extensive data for deeper bioinformatics analysis. From the GSE30529 dataset based on diabetic nephropathy tubular samples, we identified 345 genes through differential expression analysis and weighted gene coexpression correlation network analysis. GO annotations mainly included neutrophil activation, regulation of immune effector process, positive regulation of cytokine production and neutrophil-mediated immunity. KEGG pathways mostly included phagosome, complement and coagulation cascades, cell adhesion molecules and the AGE-RAGE signalling pathway in diabetic complications. Additional datasets were analysed to understand the mechanisms of differential gene expression from an epigenetic perspective. Differentially expressed miRNAs were obtained to construct a miRNA-mRNA network from the miRNA profiles in the GSE57674 dataset. The miR-1237-3p/SH2B3, miR-1238-5p/ZNF652 and miR-766-3p/TGFBI axes may be involved in diabetic nephropathy. The methylation levels of the 345 genes were also tested based on the gene methylation profiles of the GSE121820 dataset. The top 20 hub genes in the PPI network were discerned using the CytoHubba tool. Correlation analysis with GFR showed that SYK, CXCL1, LYN, VWF, ANXA1, C3, HLA-E, RHOA, SERPING1, EGF and KNG1 may be involved in diabetic nephropathy. Eight small molecule compounds were identified as potential therapeutic drugs using Connectivity Map.

Evaluation of Urinary Neutrophil Gelatinase Associated Lipocalin and Kidney Injury Molecule-1 as Diagnostic Markers for Early Nephropathy in Patients with Type 2 Diabetes Mellitus

PURPOSE

The purpose of this study was evaluating the early diagnostic value of two specific tubular markers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in diabetes nephropathy.

PATIENTS AND METHODS

Cross-sectional study was carried in three groups of patients from 10/2017 to 10/2018 in Military Hospital 103. Group I included 30 healthy peoples with estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m2 and urine albumin creatinine ratio (uACR) <30 mg/g. Group II included 30 type 2 diabetic patients having uACR <30 mg/g, eGFR >60 mL/min/1.73 m2. Group III included 30 type 2 diabetic patients having uACR >30 mg/g, eGFR >60 mL/min/1.73 m2.

RESULTS

Urine KIM-1 and NGAL increased progressively from control group (57.29 ± 25.91 pg/mL; 25.71 ± 13.69 ng/mL) to the group of diabetic patients with uACR <30 mg/g (167.06 ± 44.01 pg/mL; 37.42 ± 10.89 ng/mL) and the group of diabetic patients with uACR ≥30 mg/g) (p < 0.05). There were moderate correlations between KIM-1 (r = 0.48, p < 0.05) and NGAL (r = 0.45, p < 0.05) with uACR. There was a mild correlation between KIM-1 and NGAL (r = 0.29, p < 0.05). KIM-1 and NGAL are the independent tests to detect diabetic nephropathy. The sensivity and specificity of KIM-1 with cut-off value of 174.95 pg/mL were 62.37% and 73.48%, respectively; the sensivity and specificity of NGAL with cut-off value of 35.2 ng/mL were 60.45% and 70.37%, respectively.

CONCLUSION

KIM-1 and NGAL in urine are independent markers for early diagnostic diabetic nephropathy.

Wingless-type MMTV integration site family member 5a: a novel biomarker regulated in type 2 diabetes mellitus and diabetic kidney disease

Objectives

Type 2 diabetes mellitus (T2DM) is sustained by insulin resistance (IR) and reduced β-cell mass, which is largely due to insulin secretory dysfunction. Wnt5a protein is essential to islet formation and β-cell migration in the development of pancreas in vertebrates. Levels of the Wnt5a protein antagonist plasma secreted frizzled-related protein 5 (Sfrp5) were elevated in patients with T2DM. However, the association between Wnt5a, T2DM patients and diabetic kidney disease (DKD) is unknown. We aim to investigate the circulating Wnt5a levels in in different clinical stages of T2DM and evaluate its correlation of duration of diabetes mellitus chronic complication.

Methods

A total of 329 participants (187 males, 142 females; age range 40 to 80 years) were enrolled in this study. Serum Wnt5a levels were measured by an enzyme-linked immunosorbent assay (ELISA). The demographic and clinical parameters evaluated in subjects with new onset T2DM, onset T2DM after treatment and DKD at different clinical phases.

Results

Wnt5a was significantly down-regulated in newly diagnosed T2DM patients and gradually increased after 3 months of treatment. Interesting, serum wnt5a was gradually increased in patients with long-term diabetes and kidney disease compared to patients with T2DM and onset DKD.

Conclusions

We speculated that the Wnt5a protein might regulate islet function and be involved in the onset of diabetes as a protective factor. It may be one of the inflammatory factors adversely involved in the progression of diabetic nephropathy.