Evolving spectrum of diabetic nephropathy

Role of GDF-15 in diabetic nephropathy: mechanisms, diagnosis, and therapeutic potential

PURPOSE

Growth differentiation factor 15 (GDF-15) is a cytokine involved in regulating homeostasis, and its expression is up-regulated in response to injury, stress, and inflammation. This study explored the role of GDF-15 in diabetic nephropathy (DN), a severe complication of diabetes mellitus, and its potential as a biomarker for disease progression.

METHODS

As a member of the transforming growth factor-β superfamily, GDF-15 exhibits its renal protective functions primarily through its anti-inflammatory effects and the up-regulation of other renal protective factors. This study evaluated the association between circulating GDF-15 levels and DN progression, examining the underlying mechanisms.

RESULTS

Circulating GDF-15 levels are closely linked to the development and progression of DN. While existing research has yielded some consistent conclusions, a comprehensive understanding of the role of GDF-15 in DN pathogenesis is needed to identify new therapeutic targets and strategies.

CONCLUSION

GDF-15 has the potential to be a prognostic and diagnostic biomarker for DN. It is crucial to establish appropriate reference ranges and explore their clinical utility in routine practice for validating the role of GDF-15 in DN management. Further interventional studies are required to confirm its clinical value in diagnosing and predicting the progression of DN.

Schisandrin A Attenuates Diabetic Nephropathy via EGFR/AKT/GSK3β Signaling Pathway Based on Network Pharmacology and Experimental Validation

Diabetic nephropathy (DN) is one of the common complications of diabetes and the main cause of end-stage renal disease (ESRD) in clinical practice. Schisandrin A (Sch A) has multiple pharmacological activities, including inhibiting fibrosis, reducing apoptosis and oxidative stress, and regulating immunity, but its pharmacological mechanism for the treatment of DN is still unclear. In vivo, streptozotocin (STZ) and a high-fat diet were used to induce type 2 diabetic rats, and Sch A was administered for 4 weeks. At the same time, protein-protein interaction (PPI) networks were established to analyze the overlapping genes of DN and Sch A. Subsequently, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were performed to determine the hub pathway. In addition, molecular docking was used to preliminarily verify the affinity of hub proteins and Sch A. Further, H&E staining, Sirius red staining, immunohistochemistry, immunofluorescence, and western blot analysis were used to detect the location and expression of related proteins in DN. This study revealed the multi-target and multi-pathway characteristics of Sch A in the treatment of DN. First, Sch A could effectively improve glucose tolerance, reduce urine microprotein and urine creatinine levels, and alleviate renal pathological damage in DN rats. Second, EGFR was the hub gene screened in overlapping genes (43) of Sch A (100) and DN (2524). Finally, it was revealed that Sch A could inhibit the protein expression levels of EGFR and PTRF and reduced the expression of apoptosis-related proteins, and this effect was related to the modulation of the AKT/GSK-3β signaling pathway. In summary, Sch A has a protective effect in DN rats, EGFR may be a potential therapeutic target, throughout modulating AKT/GSK-3β pathway.

Syndecans and diabetic complications: A narrative review

Syndecan (SDC) is a member of the heparan sulfate proteoglycan (HSPG) family. It appears to play a role in the aetiology of diabetic complications, with decreased levels of SDCs being reported in the kidney, retina, and cardiac muscle in models of diabetes mellitus (DM). The reduced levels of SDCs may play an important role in the development of albuminuria in DM. Some studies have provided the evidence supporting the mechanisms underlying the role of SDCs in DM. However, SDCs and the molecular mechanisms involved are complex and need to be further elucidated. This review focuses on the underlying molecular mechanisms of SDCs that are involved in the development and progression of the complications of DM, which may help in developing new strategies to prevent and treat these complications.

Urinary biomarkers in diabetic nephropathy

Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although microalbuminuria is considered the best non-invasive marker for DN, better predictive markers are needed of sufficient sensitivity and specificity to detect disease in general and in early disease specifically. Even prior to appearance of microalbuminuria, urinary biomarkers increase in diabetics and can serve as accurate nephropathy biomarkers even in normoalbuminuria. In this review, a number of novel urine biomarkers including those reflecting kidney damage caused by glomerular/podocyte damage, tubular damage, oxidative stress, inflammation, and intrarenal renin-angiotensin system activation are discussed. Our review also includes emerging biomarkers such as urinary microRNAs. These short noncoding miRNAs regulate gene expression and could be utilized to identify potential novel biomarkers in DN development and progression. .

The impact of chitooligosaccharides with a certain degree of polymerization on diabetic nephropathic mice and high glucose-damaged HK-2 cells

Diabetic nephropathy (DN) is a primary diabetic complication ascribed to the pathological changes in renal microvessels. This study investigated the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch ECH associating protein (Keap1)/antioxidant response element (ARE) signaling pathway impact of chitooligosaccharides (COS) with a certain degree of polymerization (DP) on DN mouse models and high glucose-damaged human kidney 2 (HK-2) cells. The findings indicated that COS effectively reduced the renal function indexes (uric acid [UA], urinary albumin excretion rate [UAER], urine albumin-to-creatinine ratio [UACR], blood urea nitrogen [BUN], and creatinine [Cre]) of DN mice. It increased (p < .05) the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) antioxidant enzyme activity in the serum and kidneys, and decreased (p < .05) the malondialdehyde (MDA) content. The mechanistic investigation showed that COS significantly increased (p < .05) Nrf2 and downstream target gene (GCLM, GCLC, HO-1, and NQO-1) expression, and substantially decreased (p < .05) Keap1 expression. The protein level was consistent with the messenger RNA (mRNA) level in in vitro and in vivo models. The docking data indicated that COS and Keap1 protein binding included six hydrogen bond formation processes (Gly364, Arg415, Arg483, His436, Ser431, and Arg380). The COS intervention mechanism may be related to the Nrf2/Keap1/ARE antioxidant pathway. Therefore, it provides a scientific basis for COS application in developing special medical food for DN patients.

Consumption of red, white, and processed meat and odds of developing kidney damage and diabetic nephropathy (DN) in women: a case control study

Diabetic nephropathy (DN) is one of the most prevalent and severe complications of diabetes mellitus (DM) and is associated with increased morbidity and mortality. We aimed to investigate the associations between red, processed, and white meat consumption and the odds of developing kidney damage and DN in women. We enrolled 105 eligible women with DN and 105 controls (30-65 years). A validated and reliable food frequency questionnaire (FFQ) was used to evaluate the consumption of red, processed, and white meat. Biochemical variables and anthropometric measurements were assessed for all patients using pre-defined protocols. Binary logistic regression was conducted to examine possible associations. The results of the present study showed that there was a direct significant association between high consumption of red meat and processed meats and odds of microalbuminuria (red meat 2.30, 95% CI 1.25, 4.22; P-value = 0.007, processed meat: OR 2.16, 95% CI 1.18, 3.95; P-value = 0.01), severe albuminuria (red meat OR 3.25, 95% CI 1.38, 7.46; P-value = 0.007, processed meat: OR 2.35, 95% CI 1.01, 5.49; P-value = 0.04), BUN levels (red meat: OR 2.56, 95% CI 1.10, 5.93; P-value = 0.02, processed meat: OR 2.42, 95% CI 1.04, 5.62; P-value = 0.03), and DN (red meat 2.53, 95% CI 1.45, 4.42; P-value = 0.001, processed meat: OR 2.21; 95% CI 1.27, 3.85; P-value = 0.005). In summary, our study suggests that higher consumption of red and processed meat sources may be associated with microalbuminuria, severe albuminuria, higher BUN level, and higher odds of DN.

Serum cell division cycle 42 reflects the development and progression of diabetic nephropathy in patients with diabetes mellitus

Cell division cycle 42 (CDC42) regulates podocyte apoptosis to take part in the development and progression of diabetic nephropathy (DN), but currently the clinical evidence is limited. The aim of the present study was to investigate the capability of serum CDC42 expression level to estimate the development and progression of DN in patients with diabetes mellitus (DM). Patients with type 2 DM (n=306) were enrolled and divided into normoalbuminuria (n=185), microalbuminuria (n=72) and macroalbuminuria (n=49) groups based on the urinary albumin-to-creatinine ratio. Serum CDC42 was measured in all subjects using enzyme-linked immunosorbent assay. The median (interquartile range) CDC42 in patients with DM was 0.461 (0.314-0.690) ng/ml (range, 0.087-1.728 ng/ml). CDC42 was positively associated with the estimated glomerular filtration rate (P<0.001), but negatively correlated with body mass index, systolic blood pressure, hemoglobin A1c, serum creatine, serum uric acid and C reactive protein (all P<0.050). CDC42 levels were lowest in the macroalbuminuria group, followed by the microalbuminuria group, and were highest in the normoalbuminuria group (P<0.001). CDC42 indicated that it was a favorable estimator for the presence of albuminuria [area under the curve (AUC), 0.792; 95% confidence interval (CI), 0.736-0.848] and macroalbuminuria (AUC, 0.845; 95% CI, 0.775-0.915). By analyses in four different multivariate logistic regression models, increased CDC42 was independently associated with the presence of microalbuminuria (all P<0.001), macroalbuminuria (most P<0.001) and microalbuminuria + macroalbuminuria (all P<0.001). Serum CDC42 level negatively correlated with microalbuminuria and macroalbuminuria in patients with DM, suggesting its ability for estimating the development and progression of DN.

Jin-Gui-Shen-Qi Wan alleviates fibrosis in mouse diabetic nephropathy via MHC class II

ETHNOPHARMACOLOGICAL RELEVANCE

Jin-Gui-Shen-Qi Wan (JGSQW) is a traditional Chinese medicine formula that has been traditionally used to alleviate urinary system ailments such as frequent urination and polyuria. Clinical studies have indicated that when combined with hypoglycaemic drugs, JGSQW exhibits a synergistic effect and can improve diabetic nephropathy (DN), yet its underlying mechanism and targets remain unclear.

AIM OF THE STUDY

This study aims to investigate the therapeutic efficacy of JGSQW and its underlying mechanisms using a DN db/db mouse model.

MATERIALS AND METHODS

Ultrahigh-performance liquid chromatography coupled with mass spectrometry was utilized to analyse the primary active compounds, blood levels, and pharmacokinetics of JGSQW. Additionally, the therapeutic effects of JGSQW and metformin on blood glucose levels, lipid levels, renal function, and renal pathology in diabetic nephropathy mice were investigated using a db/db mouse model. Proteomic analysis was carried out to identify the primary target of JGSQW in treating DN. The mechanism of action was verified by western blotting, immunohistochemistry, and immunofluorescence. Then, molecular docking and molecular dynamics, transfection, drug affinity responsive target stability (DARTS) assay and cell thermal migration assay (CETSA) further validated the targeted binding effect.

RESULTS

JGSQW combined with metformin significantly improved the blood glucose levels, blood lipids, renal function, and renal pathology of DN mice. JGSQW mainly exerted its therapeutic effect on DN by targeting major histocompatibility complex class II (MHC class II) molecules. Immunohistochemistry results showed that JGSQW inhibited the expression of collagen I, fibronectin, and alpha smooth muscle actin (α-SMA) expression. Immunofluorescence and Western blot results showed that JGSQW inhibited the expression of H2-Ab1 and H2-Aa, which are MHC class II molecules, thereby suppressing CD4+ T-cell infiltration and improving diabetic kidney fibrosis. The binding ability of paeoniflorin to H2-Aa was predicted and verified by molecular, DARTS, and CETSA assays. Treatment with 80 μM paeoniflorin effectively alleviated high glucose-induced injury in the MPC-5 injury model. H2-Aa was overexpressed at this model concentration, and Western blotting further confirmed that paeoniflorin reduced glomerular podocyte fibrosis by regulating H2-Aa.

CONCLUSIONS

JGSQW combined with metformin may have a synergistic effect to alleviates renal fibrosis in diabetic nephropathy by downregulating immune complex MHC class II molecules and attenuating the antigen presentation effect of MHC class II on CD4.

Utilizing machine learning algorithms to identify biomarkers associated with diabetic nephropathy: A review

Diabetic nephropathy (DN), a multifaceted disease with various contributing factors, presents challenges in understanding its underlying causes. Uncovering biomarkers linked to this condition can shed light on its pathogenesis and support the creation of new diagnostic and treatment methods. Gene expression data were sourced from accessible public databases, and Weighted Gene Co-expression Network Analysis (WGCNA)was employed to pinpoint gene co-expression modules relevant to DN. Subsequently, various machine learning techniques, such as random forest, lasso regression algorithm (LASSO), and support vector machine-recursive feature elimination (SVM-REF), were utilized for distinguishing DN cases from controls using the identified gene modules. Additionally, functional enrichment analyses were conducted to explore the biological roles of these genes. Our analysis revealed 131 genes showing distinct expression patterns between controlled and uncontrolled groups. During the integrated WCGNA, we identified 61 co-expressed genes encompassing both categories. The enrichment analysis highlighted involvement in various immune responses and complex activities. Techniques like Random Forest, LASSO, and SVM-REF were applied to pinpoint key hub genes, leading to the identification of VWF and DNASE1L3. In the context of DN, they demonstrated significant consistency in both expression and function. Our research uncovered potential biomarkers for DN through the application of WGCNA and various machine learning methods. The results indicate that 2 central genes could serve as innovative diagnostic indicators and therapeutic targets for this disease. This discovery offers fresh perspectives on the development of DN and could contribute to the advancement of new diagnostic and treatment approaches.

Salvianolic acid B and tanshinone IIA synergistically improve early diabetic nephropathy through regulating PI3K/Akt/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is one of the most common and serious complications of diabetes, which lacks effective treatment. Salviae Miltiorrhizae Radix Et Rhizoma is one of the key compatible traditional Chinese medicine in the prescription for the treatment of DN. Salvianolic acid B and tanshinone IIA are two monomer active components with high content and clear structure in Salvia miltiorrhiza, which can effectively improve early (DN), respectively.

AIM OF THE STUDY

To evaluate the compatible effect of salvianolic acid B and tanshinone IIA on early DN rats and elucidate the mechanism.

METHODS

Early DN rats were induced by streptozotocin combined with high glucose and high fat diet, and intervened by salvianolic acid B, tanshinone IIA and their combinations. The pathological sections of kidney, liver and biochemical indexes were analyzed. Network pharmacology method was used to predict the possible mechanism. The mechanisms were elucidated by metabolomics, Elisa, and Western blot.

RESULTS

Given our analysis, salvianolic acid B and tanshinone IIA can synergistically regulate 24 h UTP, Urea and Scr and improve kidney damage in early DN rats. The metabolic abnormalities of early DN rats were improved by regulating the biosynthesis of saturated fatty acids, glycerol phospholipid metabolism, steroid biosynthesis, alanine, and arachidonic acid. Salvianolic acid B combined with tanshinone IIA at a mass ratio of 13.4:1 can significantly reduce kidney inflammation, up-regulate p-PI3K/PI3K and p-Akt/Akt and down-regulate p-NF-κB/NF-κB, which better than the single-used group and can be reversed by PI3K inhibitor LY294002.

CONCLUSION

Salvianolic acid B and tanshinone IIA can synergistically improve glucose and lipid disorders, liver and kidney damage, and resist kidney inflammation in early DN rats, and the mechanism may be related to regulating PI3K/Akt/NF-κB signaling pathway.

Effect and Mechanisms of Huangqi-Shanzhuyu in the Treatment of Diabetic Nephropathy based on Network Pharmacology and In Vitro Experiments

BACKGROUND

Huangqi-Shanzhuyu (HS), a classic combination of Chinese herbal formulae, has been widely used for the treatment of diabetic nephropathy (DN). However, its pharmacological mechanism of action is still unclear.

METHODS

The active ingredients of HS and their potential targets were identified through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and the DN-related targets were determined from GeneCards, Online Mendelian Inheritance in Man (OMIM), PharmGkb, and Therapeutic Target Database (TTD). The Cytoscape software was used to construct a herb-disease-target network and screen core genes. STRING was employed to generate a protein-protein interaction (PPI) network. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to predict the mechanism of action of HS in DN. Animal experiments and molecular docking were used to verify the potential mechanism.

RESULTS

In total, 40 active ingredients and 180 effective targets of HS in DN were identified and 1115 DN-related targets were retrieved. From the PPI network, VEGFA, AKT1, IL6, IL1B, TP53, MMP9, PTGS2, CASP3, EGF and EGFR were identified as core genes. The anti-DN mechanism mainly involved multiple signaling pathways such as AGEs-RAGE. Animal experiments and molecular docking analysis confirmed that HS downregulated the expression of IL-1 and IL-6 via kaempferol-mediated inhibition of JNK1 phosphorylation.

CONCLUSION

HS exhibits a therapeutic effect in DN through its multiple ingredients that act on several targets and multiple signaling pathways, including AGEs-RAGE.

The Mechanism of Plantaginis Semen in the Treatment of Diabetic Nephropathy based on Network Pharmacology and Molecular Docking Technology

BACKGROUND

Diabetic nephropathy (DN) is one of the common complications of diabetes. Plantaginis Semen (PS) has a variety of therapeutic effects, however its mechanism on DN is unclear.

OBJECTIVE

This paper aims to find the ingredients, the key targets, and the action pathways of PS on DN from the perspective of network pharmacology.

METHODS

The databases of network pharmacology, such as Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), Pharmmapper, OMIM, DrugBank, Gene- Cards, TTD, Disgenet, STRING, and Cytoscape software, were used to find the main ingredients and targets. Gene Ontology (GO) function and Kyoto Encyclopedia of Genome and Genomes (KEGG) pathway enrichment analysis were used to reveal the potential pathways of the PS on DN. The GEO database was used to find the targets of DN based on valid experimental research. The molecular docking technology was used to evaluate the combination between ingredients of PS and the targets.

RESULTS

A total of 9 active ingredients and 216 potential therapeutic targets were obtained for PS on DN. Hub targets were discovered by the Cytoscape software analysis. CASP3 was screened by Venn diagram by making intersection between GSE30529 and hub genes. Moreover, CASP3 was combined with one of the nine active ingredients, quercetin, by molecular docking analysis. The KEGG pathways were mainly involved in diabetic nephropathy, and were simultaneously associated with CASP3 as followed: AGE-RAGE signaling pathway in diabetic complications, apoptosis, lipid and atherosclerosis, MAPK signaling pathway, TNF signaling pathway, IL-17 signaling pathway, and p53 signaling pathway.

CONCLUSION

PS can have the treatment on DN through CASP3. Quercetin, as one of the nine active ingredients, can be bounded to CASP3 to inhibit apoptosis in DN. PS can also take action on DN probably through many pathways. The role of PS on DN through other pathways still needs to be further elaborated.

Inhibition of the lncRNA 585189 prevents podocyte injury and mitochondria dysfunction by promoting hnRNP A1 and SIRT1 in diabetic nephropathy

Podocyte dysfunction has been identified as a crucial pathological characteristic of diabetic nephropathy (DN). However, the regulatory effects of long non-coding RNAs (lncRNAs) in this process have not been fully elucidated. Here, we performed an unbiased RNA-sequencing (RNA-seq) analysis of renal tissues and identified a significantly upregulated long non-coding RNA, ENST00000585189.1 (lncRNA 585189), in patients with DN. Furthermore, lncRNA 585189 was positively correlated with renal insufficiency and was upregulated in both DN patients and high-glucose-induced human podocytes. Gain- and loss-of-function experiments revealed that silencing lncRNA 585189 decreased the production of ROS, rescued aberrant mitochondrial morphology and membrane potential, and alleviated podocyte damage caused by high glucose. Mechanistically, bioinformatics analysis predicted an interaction between lncRNA 585189 and hnRNP A1, which was subsequently confirmed by RIP, pull-down, and EMSA assays. Further investigation revealed that lncRNA 585189 destabilizes the hnRNP A1 protein, leading to the downregulation of its expression. Conversely, hnRNP A1 promoted the expression of lncRNA 585189. Moreover, both RIP and pull-down assays demonstrated a direct interaction between hnRNP A1 and SIRT1, which enhanced SIRT1 mRNA stability. Our findings suggest that lncRNA 585189 suppresses SIRT1 through hnRNP A1, thereby hindering the recovery from mitochondrial abnormalities and podocyte damage. In summary, targeting lncRNA 585189 is a promising strategy for reversing mitochondrial dysfunction and treating DN.

Jiangtang Decoction Ameliorates Diabetic Kidney Disease Through the Modulation of the Gut Microbiota

Purpose

This study aimed to elucidate the impact of Jiangtang decoction (JTD) on diabetic kidney disease (DKD) and its association with alterations in the gut microbiota.

Methods

Using a diabetic mouse model (KK-Ay mice), daily administration of JTD for eight weeks was undertaken. Weekly measurements of body weight and blood glucose were performed, while kidney function, uremic toxins, inflammation factors, and fecal microbiota composition were assessed upon sacrifice. Ultra-structural analysis of kidney tissue was conducted to observe the pathological changes.

Results

The study findings demonstrated that JTD improve metabolism, kidney function, uremic toxins and inflammation, while also exerting a modulatory effect on the gut microbiota. Specifically, the genera Rikenella, Lachnoclostridium, and unclassified_c_Bacilli exhibited significantly increased abundance following JTD treatment, accompanied by reduced abundance of norank_f_Lachnospiraceae compared to the model group. Importantly, Rikenella and unclassified_c_Bacilli demonstrated negative correlations with urine protein levels. Lachnoclostridium and norank_f_Lachnospiraceae were positively associated with creatinine (Cr), indoxyl sulfate (IS) and interleukin (IL)-6. Moreover, norank_f_Lachnospiraceae exhibited positive associations with various indicators of DKD severity, including weight, blood glucose, urea nitrogen (UN), kidney injury molecule-1 (KIM-1) levels, trimethylamine-N-oxide (TMAO), p-cresyl sulfate (pCS), nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) and IL-17A production.

Conclusion

These findings suggested that JTD possess the ability to modulate the abundance of Rikenella, Lachnoclostridium, unclassified_c_Bacilli and norank_f_Lachnospiraceae within the gut microbiota. This modulation, in turn, influenced metabolic processes, kidney function, uremic toxin accumulation, and inflammation, ultimately contributing to the amelioration of DKD.

N6-methyladenosine methylation regulator RBM15 promotes the progression of diabetic nephropathy by regulating cell proliferation, inflammation, oxidative stress, and pyroptosis through activating the AGE-RAGE pathway

BACKGROUND

Diabetic nephropathy (DN) is a major cause of end-stage renal disease throughout the world, and m6A modification plays a critical role in the progression of DN. We aimed to find m6A-related genes and their regulatory mechanisms in DN.

METHODS

The expression levels of four important m6A-related genes (METTL16, RBM15, IGF2BP1, and ALKBH5) were detected by quantitative real-time PCR (RT-qPCR). RBM15 was chosen and its function was explored. The downstream pathway of RBM15 was screened by transcriptome sequencing. The levels of AGE, inflammation, and oxidative stress were determined with enzyme-linked immunosorbent assay, and the expression of AGE-RAGE pathway-related proteins were detected by Western blot (WB). Cell proliferation was assessed by Cell counting Kit-8 (CCK-8). The levels of pyroptosis-related proteins were evaluated by RT-qPCR or WB.

RESULTS

METTL16 and RBM15 were up regulated in the mouse model of DN, in which RBM15 was more significant. Silencing RBM15 recovered cell proliferation, reduced the levels of inflammation factors, and inhibited cell pyroptosis in high glucose-induced HK-2 cells. Transcriptome sequencing suggested that the AGE-RAGE pathway might be downstream of RBM15. RBM15 knockdown reduced AGE level and the expression of AGE-RAGE pathway-related proteins. After silencing RBM15, we found that activating the AGE-RAGE pathway inhibited cell proliferation, increased the levels of inflammation factors, promoted oxidative stress, and induced cell pyroptosis in HK-2 cell model of DN.

CONCLUSION

The m6A-related gene RBM15 inhibited cell proliferation, promoted inflammation, oxidative stress, and cell pyroptosis, thereby facilitating the progression of DN through the activation of the AGE-RAGE pathway.

Vascular complications of diabetes: A narrative review

Diabetes mellitus is a complex chronic metabolic disease characterized by hyperglycemia and various complications. According to the different pathophysiological mechanisms, these complications can be classified as microvascular or macrovascular complications, which have long-term negative effects on vital organs such as the eyes, kidneys, heart, and brain, and lead to increased patient mortality. Diabetes mellitus is a major global health issue, and its incidence and prevalence have increased significantly in recent years. Moreover, the incidence is expected to continue to rise as more people adopt a Western lifestyle and diet. Thus, it is essential to understand the epidemiology, pathogenesis, risk factors, and treatment of vascular complications to aid patients in managing the disease effectively. This paper provides a comprehensive review of the literature to clarify the above content. Furthermore, this paper also delves into the correlation between novel risk factors, such as long noncoding RNAs, gut microbiota, and nonalcoholic fatty liver disease, with diabetic vascular complications.

Metabolic Differences in Diabetic Kidney Disease Patients with Normoalbuminuria versus Moderately Increased Albuminuria

Key Points

The pathophysiological mechanisms of diabetic kidney disease (DKD) with normal (nonalbuminuric DKD) versus moderately increased albuminuria (A-DKD) are not well-understood. Fatty acid biosynthesis and oxydation, gluconeogenesis, TCA cycle, and glucose-alanine cycle were more disturbed in patients with A-DKD compared with those with nonalbuminuric DKD with identical eGFR. DKD patients with and without microalbuminuria could represent different clinical phenotypes.

Background

The pathophysiological mechanisms of diabetic kidney disease (DKD) with normal versus moderately increased albuminuria (nonalbuminuric DKD [NA-DKD] and A-DKD) are currently not well-understood and could have implications for diagnosis and treatment.

Methods

Fourteen patients with NA-DKD with urine albumin–creatinine ratio <3 mg/mmol, 26 patients with A-DKD with albumin–creatinine ratio 3–29 mg/mmol, and 60 age- and sex-matched healthy controls were randomly chosen from a population-based cohort study (Nord-Trøndelag Health Study-3, Norway). Seventy-four organic acids, 21 amino acids, 21 biogenic acids, 40 acylcarnitines, 14 sphingomyelins, and 88 phosphatidylcholines were quantified in urine. One hundred forty-six patients with diabetes from the US-based Chronic Renal Insufficiency Cohort study were used to verify main findings.

Results

Patients with NA-DKD and A-DKD had similar age, kidney function, diabetes treatment, and other traditional risk factors. Still, partial least-squares discriminant analysis showed strong metabolite-based separation (R2, 0.82; Q2, 0.52), with patients with NA-DKD having a metabolic profile positioned between the profiles of healthy controls and patients with A-DKD. Seventy-five metabolites contributed significantly to separation between NA-DKD and A-DKD (variable importance in projection scores ≥1.0) with propionylcarnitine (C3), phosphatidylcholine C38:4, medium-chained (C8) fatty acid octenedioic acid, and lactic acid as the top metabolites (variable importance in projection scores, 2.7–2.2). Compared with patients with NA-DKD, those with A-DKD had higher levels of short-chained acylcarnitines, higher long-chained fatty acid levels with more double bounds, higher branched-chain amino acid levels, and lower TCA cycle intermediates. The main findings were similar by random forest analysis and in the Chronic Renal Insufficiency Cohort study. Formal enrichment analysis indicated that fatty acid biosynthesis and oxydation, gluconeogenesis, TCA cycle, and glucose-alanine cycle were more disturbed in patients with A-DKD compared with those with NA-DKD with identical eGFR. We also found indications of a Warburg-like effect in patients with A-DKD (i.e. , metabolism of glucose to lactate despite adequate oxygen).

Conclusion

DKD patients with normoalbuminuria differ substantially in their metabolic disturbances compared with patients with moderately increase albuminuria and could represent different clinical phenotypes.

Effects of Glycemic Variability on Regulatory T Cells in Patients with Type 2 Diabetes and Kidney Disease

Purpose

To investigate the pathogenesis of diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM), we evaluated the effects of short-term glycemic variability (GV) on the profile of T cell subpopulations.

Methods

A total of 47 T2DM patients with normoalbuminuria, 47 microalbuminuria, and 49 macroalbuminuria were enrolled. The continuous glucose monitoring (CGM) determined the GV of enrolled patients. Flow cytometry was used to determine the proportion of T cell subpopulations.

Results

The frequency of T helper (Th) 17 and Th1 cells significantly increased while regulatory T cells (Tregs) significantly decreased in the macroalbuminuria group compared to normoalbuminuria and microalbuminuria groups (P < 0.01). The suppressive function of Tregs was significantly lower in the macroalbuminuria group than the normoalbuminuria group (P < 0.05). Compared with the normoalbuminuria group, the mean amplitude of glucose excursions (MAGE) of the macroalbuminuria group was significantly higher (P<0.05). Furthermore, there were negative associations between the proportion of Tregs and MAGE.

Conclusions

Increased GV could decrease the proportion of Tregs and may impair their function. This may lead to increases in Th1 and Th17 cells, and some inflammatory cytokines, which might contribute to the development and progression of DKD in T2DM.

Oxidative stress and inflammation in diabetic nephropathy: role of polyphenols

Diabetic nephropathy (DN) often leads to end-stage renal disease. Oxidative stress demonstrates a crucial act in the onset and progression of DN, which triggers various pathological processes while promoting the activation of inflammation and forming a vicious oxidative stress-inflammation cycle that induces podocyte injury, extracellular matrix accumulation, glomerulosclerosis, epithelial-mesenchymal transition, renal tubular atrophy, and proteinuria. Conventional treatments for DN have limited efficacy. Polyphenols, as antioxidants, are widely used in DN with multiple targets and fewer adverse effects. This review reveals the oxidative stress and oxidative stress-associated inflammation in DN that led to pathological damage to renal cells, including podocytes, endothelial cells, mesangial cells, and renal tubular epithelial cells. It demonstrates the potent antioxidant and anti-inflammatory properties by targeting Nrf2, SIRT1, HMGB1, NF-κB, and NLRP3 of polyphenols, including quercetin, resveratrol, curcumin, and phenolic acid. However, there remains a long way to a comprehensive understanding of molecular mechanisms and applications for the clinical therapy of polyphenols.

A2BAR Antagonism Decreases the Glomerular Expression and Secretion of Chemoattractants for Monocytes and the Pro-Fibrotic M2 Macrophages Polarization during Diabetic Nephropathy

Some chemoattractants and leukocytes such as M1 and M2 macrophages are known to be involved in the development of glomerulosclerosis during diabetic nephropathy (DN). In the course of diabetes, an altered and defective cellular metabolism leads to the increase in adenosine levels, and thus to changes in the polarity (M1/M2) of macrophages. MRS1754, a selective antagonist of the A2B adenosine receptor (A2BAR), attenuated glomerulosclerosis and decreased macrophage-myofibroblast transition in DN rats. Therefore, we aimed to investigate the effect of MRS1754 on the glomerular expression/secretion of chemoattractants, the intraglomerular infiltration of leukocytes, and macrophage polarity in DN rats. Kidneys/glomeruli of non-diabetic, DN, and MRS1754-treated DN rats were processed for transcriptomic analysis, immunohistopathology, ELISA, and in vitro macrophage migration assays. The transcriptomic analysis identified an upregulation of transcripts and pathways related to the immune system in the glomeruli of DN rats, which was attenuated using MRS1754. The antagonism of the A2BAR decreased glomerular expression/secretion of chemoattractants (CCL2, CCL3, CCL6, and CCL21), the infiltration of macrophages, and their polarization to M2 in DN rats. The in vitro macrophages migration induced by conditioned-medium of DN glomeruli was significantly decreased using neutralizing antibodies against CCL2, CCL3, and CCL21. We concluded that the pharmacological blockade of the A2BAR decreases the transcriptional expression of genes/pathways related to the immune response, protein expression/secretion of chemoattractants, as well as the infiltration of macrophages and their polarization toward the M2 phenotype in the glomeruli of DN rats, suggesting a new mechanism implicated in the antifibrotic effect of MRS1754.

Single Nucleotide Polymorphisms of the RAC1 Gene as Novel Susceptibility Markers for Neuropathy and Microvascular Complications in Type 2 Diabetes

Single nucleotide polymorphisms (SNP) in the RAC1 (Rac family small GTPase 1) gene have recently been linked to type 2 diabetes (T2D) and hyperglycemia due to their contribution to impaired redox homeostasis. The present study was designed to determine whether the common SNPs of the RAC1 gene are associated with diabetic complications such as neuropathy (DN), retinopathy (DR), nephropathy, angiopathy of the lower extremities (DA), and diabetic foot syndrome. A total of 1470 DNA samples from T2D patients were genotyped for six common SNPs by the MassArray Analyzer-4 system. The genotype rs7784465-T/C of RAC1 was associated with an increased risk of DR (p = 0.016) and DA (p = 0.03) in males, as well as with DR in females (p = 0.01). Furthermore, the SNP rs836478 showed an association with DR (p = 0.005) and DN (p = 0.025) in males, whereas the SNP rs10238136 was associated with DA in females (p = 0.002). In total, three RAC1 haplotypes showed significant associations (FDR < 0.05) with T2D complications in a sex-specific manner. The study's findings demonstrate, for the first time, that the RAC1 gene's polymorphisms represent novel and sex-specific markers of neuropathy and microvascular complications in type 2 diabetes, and that the gene could be a new target for the pharmacological inhibition of oxidative stress as a means of preventing diabetic complications.

Network pharmacology analysis combined with experimental validation to explore the therapeutic mechanism of Schisandra Chinensis Mixture on diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is one of the most common and serious microvascular complications of Diabetes mellitus (DM). The inflammatory response plays a critical role in DN. Schisandra Chinensis Mixture (SM) has shown promising clinical efficacy in the treatment of DN while the pharmacological mechanisms are still unclear.

AIM OF THE STUDY

In this study, a network pharmacology approach and bioinformatic analysis were adopted to predict the pharmacological mechanisms of SM in DN therapy. Based on the predicted results, molecular docking and in vivo experiments were used for verification.

MATERIALS AND METHODS

In this study, the candidate bioactive ingredients of SM were obtained via Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) and supplementing according to the literature. SM putative targets and the verified targets were acquired from TCMSP and SiwssTartgetPrediction Database. DN-related target genes were collected from GeneCards, OMIM, DisGeNET databases, and microarray data analysis. Biological function and pathway analysis were performed to further explore the pharmacological mechanisms of SM in DN therapy. The protein-protein interaction (PPI) network was established to screen the hub gene. The Receiver Operating Characteristic (ROC) analysis and the molecular docking simulations were performed to validate the potential target-drug interactions. The fingerprint spectrum of multi-components of the SM was characterized by UPLC-MS/MS. The signaling pathways associated with inflammation and hub genes were partially validated in SD rats.

RESULTS

A total of 36 bioactive ingredients were contained, and 666 component-related targets were screened from SM, of which 50 intersected with DN targets and were considered potential therapeutic targets. GO analyses revealed that the 50 intersection targets were mainly enriched in the inflammatory response, positive regulation of angiogenesis, and positive regulation of phosphatidylinositol 3-kinase(PI3K) signaling. KEGG analyses indicated that the PI3K-Akt signaling pathway was considered as the most important pathway for SM antagonism to the occurrence and development of DN, with the highest target count enrichment. PPI network results showed that the top 15 protein targets in degree value, VEGFA, JAK2, CSF1R, NOS3, CCR2, CCR5, TLR7, FYN, BTK, LCK, PLAT, NOS2, TEK, MMP1 and MCL1, were identified as hub genes. The results of ROC analysis showed that VEGFA and NOS3 were valuable in the diagnosis of DN. The molecular docking confirmed that the core bioactive ingredients had well-binding affinity for VEGFA and NOS3. The in vivo experiments confirmed that SM significantly inhibited the over-release of inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor receptor (TNF)-α in DN rats, while regulating the PI3K-AKT and VEGFA-NOS3 signaling pathways.

CONCLUSION

This study revealed the multi-component, multi-target and multi-pathway characteristics of SM therapeutic DN. SM inhibited the inflammatory response and improved renal pathological damage in DN rats, which was related to the regulation of the PI3K-Akt and VEGFA-NOS3 signaling pathways.

Receiver Operator Characteristic (ROC) Analysis of Lipids, Proteins, DNA Oxidative Damage, and Antioxidant Defense in Plasma and Erythrocytes of Young Reproductive-Age Men with Early Stages of Type 1 Diabetes Mellitus (T1DM) Nephropathy in the Irkutsk Region, Russia

Oxidative stress plays a leading role in the pathogenesis of diabetic nephropathy. However, many aspects of oxidative stress reactions in the initial stages of this disease are not fully understood. The men cohort is of particular interest because of the severe effects of diabetes on their urogenital system. The aim of this study is to assess the intensity of lipids, proteins, DNA oxidative damage, blood antioxidant defense enzymatic, and activity of non-enzymatic components in men with type 1 diabetes mellitus (T1DM) in the early stages of diabetic nephropathy using receiver operator characteristic (ROC) analysis. This study included eighty-nine reproductive-age men in the initial stages of diabetic nephropathy (DN) and thirty-nine age- and sex-matched individuals not suffering from glycemic disorders. The DN patients were divided into two subgroups: stage 1 patients (urinary albumin < 30 mg/day and albumin/creatinine ratio < 3 mg/mmol (n = 45)) and stage 2 patients (urinary albumin 30−300 mg/day and albumin/creatinine ratio 3−30 mg/mmol (n = 44)). Levels of oxidative damage products (conjugated dienes (CDs), thiobarbituric acid reactants (TBARs), methylglyoxal (MGO), and 8-hydroxy-2’-deoxyguanosine (8-OHdG)) and antioxidants (glutathione peroxidase (GPx), glutathione S-transferases π (GSTp), glutathione reductase (GR), copper and zinc-containing superoxide dismutase 1 (SOD-1), total antioxidant status (TAS), α-tocopherol, retinol, reduced glutathione (GSH), and oxidative glutathione (GSSG)) were estimated in plasma and erythrocytes. Oxidative damage to cellular structures (higher values of median CDs (1.68 µmol/L; p = 0.003), MGO (3.38 mg/L; p < 0.001) in the stage 1 group and CDs (2.28 µmol/L; p < 0.0001), MGO (3.52 mg/L; p < 0.001), 8-OHdG (19.44 ng/mL; p = 0.010) in the stage 2 group) and changes in the antioxidant defense system (lower values of TAS (1.14 units; p = 0.011), α-tocopherol (12.17 µmol/L; p = 0.009), GPx (1099 units; p = 0.0003) and elevated levels of retinol (1.35 µmol/L; p < 0.001) in the group with stage 1; lower values of α-tocopherol (12.65 µmol/L; p = 0.033), GPx (1029.7 units; p = 0.0001) and increased levels of GR (292.75 units; p < 0.001), GSH (2.54 mmol/L; p = 0.010), GSSG (2.31 mmol/L; p < 0.0001), and retinol (0.81 µmol/L; p = 0.005) in the stage 2 group) were identified. The ROC analysis established that the following indicators have the highest diagnostic significance for stage 1 diabetic nephropathy: CDs (AUC 0.755; p < 0.0001), TBARs (AUC 0.748; p = 0.0001), MGO (AUC 0.720; p = 0.0033), retinol (AUC 0.932; p < 0.0001), GPx (AUC 0.741; p = 0.0004), α-tocopherol (AUC 0.683; p = 0.0071), and TAS (AUC 0.686; p = 0.0052) and the following for stage 2 diabetic nephropathy: CDs (AUC 0.714; p = 0.001), TBARs (AUC 0.708; p = 0.001), 8-OHdG (AUC 0.658; p = 0.0232), GSSG (AUC 0.714; p = 0.001), and GSH (AUC 0.667; p = 0.0108). We conclude that changes in indicators of damage to lipids, proteins, DNA, and the insufficiency of antioxidant defense factors already manifest in the first stage of diabetic nephropathy in men with T1DM. The ROC established which parameters have the greatest diagnostic significance for stages 1 and 2 of diabetic nephropathy, which may be utilized as additional criteria for defining men with T1DM as being in the risk group for the development of initial manifestations of the disease and thus allow for substantiating appropriate approaches to optimize preventive measures.

Non-albuminuric Diabetic Kidney Disease Phenotype: Beyond Albuminuria

Diabetic kidney disease (DKD) is the leading cause of chronic and end-stage kidney disease worldwide. Its pathogenic mechanism is complex, and it can affect the entire structures of the kidneys such as the glomerulus, tubules and interstitium. Currently, the urinary albumin excretion rate and the estimated glomerular filtration rate are widely accepted as diagnostic criteria. However, some studies have reported a different or non-classical clinical course of DKD, with some patients showing declined kidney function with normal levels of albuminuria, known as the 'non-albuminuric DKD' phenotype. The pathogenesis of this phenotype remains unclear, but some clinical and pathological features have been postulated. This review explores the evidence regarding this topic.

Therapeutic role of mesenchymal stem cells (MSCs) in diabetic kidney disease (DKD)

Findings of preclinical studies and recent phase I/II clinical trials have shown that mesenchymal stem cells (MSCs) play a significant role in the development of diabetic kidney disease (DKD). Thus, MSCs have attracted increasing attention as a novel regenerative therapy for kidney diseases. This review summarizes recent literature on the roles and potential mechanisms, including hyperglycemia regulation, anti-inflammation, anti-fibrosis, pro-angiogenesis, and renal function protection, of MSC-based treatment methods for DKD. This review provides novel insights into understanding the pathogenesis of DKD and guiding the development of biological therapies.

Mechanisms Underlying the Differences in the Pharmacokinetics of Six Active Constituents of Huangqi Liuyi Decoction between Normal and Diabetic Nephropathy Mouse Models

The aim of this study was to explore the mechanisms underlying the differences in the pharmacokinetics of Huangqi Liuyi decoction extract (HQD) under physiological and pathological conditions. The roles of liver cytochrome P450 metabolic enzymes (Cyp450) and small intestinal transporters were also investigated. The cocktail probe drug method was used to investigate the effects of diabetic nephropathy (DN) and HQD on metabolic enzyme activity. The expression levels of liver Cyp450 metabolic enzymes (Cyp1A2, Cyp2C37, Cyp3A11, Cyp2E1, and Cyp2C11) and small intestinal transporters (breast cancer resistance protein (BCRP), P-glycoprotein (P-gp), organic cation transporters (OCTs), and multidrug resistance-associated protein (MRPs) were determined using western blot. Compared to normal mice, the expression of OCT1, OCT2, MRP1, and MRP2 was increased in DN mice, while that of P-gp and BCRP (P < 0.05 and P < 0.001) was inhibited. HQD inhibited expression of Cyp1A2 and Cyp3A11 and increased the expression of P-gp and BCRP in normal mice. In DN mice, HQD induced expression of BCRP and inhibited expression of Cyp2C37, Cyp3A11, OCT2, MRP1, and MRP2. The activity of each Cyp450 enzyme was consistent with changes in expression. The changes in pharmacokinetic parameters of HQD in DN might, in part, be secondary to decreased expression of P-gp and BCRP. HQD varied in regulating transporter activities between health and disease. These findings support careful application of HQD-based treatment in DN, especially in combination with other drugs.

Diabetic Proteinuria Revisited: Updated Physiologic Perspectives

Albuminuria, a hallmark of diabetic nephropathy, reflects not only injury and dysfunction of the filtration apparatus, but is also affected by altered glomerular hemodynamics and hyperfiltration, as well as by the inability of renal tubular cells to fully retrieve filtered albumin. Albuminuria further plays a role in the progression of diabetic nephropathy, and the suppression of glomerular albumin leak is a key factor in its prevention. Although microalbuminuria is a classic manifestation of diabetic nephropathy, often progressing to macroalbuminuria or overt proteinuria over time, it does not always precede renal function loss in diabetes. The various components leading to diabetic albuminuria and their associations are herein reviewed, and the physiologic rationale and efficacy of therapeutic interventions that reduce glomerular hyperfiltration and proteinuria are discussed. With these perspectives, we propose that these measures should be initiated early, before microalbuminuria develops, as substantial renal injury may already be present in the absence of proteinuria. We further advocate that the inhibition of the renin-angiotensin axis or of sodium-glucose co-transport likely permits the administration of a normal recommended or even high-protein diet, highly desirable for sarcopenic diabetic patients.

Hypoxia-Inducible Factors and Diabetic Kidney Disease—How Deep Can We Go?

Diabetes is one of the leading causes of chronic kidney disease (CKD), and multiple underlying mechanisms involved in pathogenesis of diabetic nephropathy (DN) have been described. Although various treatments and diagnosis applications are available, DN remains a clinical and economic burden, considering that about 40% of type 2 diabetes patients will develop nephropathy. In the past years, some research found that hypoxia response and hypoxia-inducible factors (HIFs) play critical roles in the pathogenesis of DN. Hypoxia-inducible factors (HIFs) HIF-1, HIF-2, and HIF-3 are the main mediators of metabolic responses to the state of hypoxia, which seems to be the one of the earliest events in the occurrence and progression of diabetic kidney disease (DKD). The abnormal activity of HIFs seems to be of crucial importance in the pathogenesis of diseases, including nephropathies. Studies using transcriptome analysis confirmed by metabolome analysis revealed that HIF stabilizers (HIF-prolyl hydroxylase inhibitors) are novel therapeutic agents used to treat anemia in CKD patients that not only increase endogenous erythropoietin production, but also could act by counteracting the metabolic alterations in incipient diabetic kidney disease and relieve oxidative stress in the renal tissue. In this review, we present the newest data regarding hypoxia response and HIF involvement in the pathogenesis of diabetic nephropathy and new therapeutic insights, starting from improving kidney oxygen homeostasis.

Effects of Huangqi Liuyi Decoction in the Treatment of Diabetic Nephropathy and Tissue Distribution Difference of its Six Active Constituents Between Normal and Diabetic Nephropathy Mouse Models

The purpose of this study was to investigate the effects of Huangqi Liuyi decoction extract (HQD) on diabetic nephropathy (DN), and the tissue distribution difference of six main active ingredients of HQD between normal and DN mouse models. DN mice were administered HQD for 12 weeks to investigate its efficacy in the treatment of DN. Liquid chromatography-tandem mass-spectrometry (HPLC-MS/MS) was used to analyze the tissue distribution of the six active ingredients of HQD in normal and DN mice, including astragaloside IV, calycosin-7-O-β-D-glucoside, calycosin glucuronide, ononin, formononetin, and glycyrrhizic acid. DN mice treated with HQD showed significantly decreased fasting blood glucose (FBG), 24-h urinary protein (24 h U-Alb), blood urea nitrogen (BUN), serum creatinine (Scr), and triglyceride levels (TG) (p &lt; 0.05). Moreover, there were no significant differences in pharmacodynamics between HQD and Huangqi Liuyi decoction. Treated mice also had decreased expression of collagen I, ɑ–smooth muscle actin (ɑ-SMA), and vimentin; and upregulated expression of E-cadherin in their kidneys. Compared to normal mice, distributions of the six ingredients in the liver, heart, spleen, lungs, kidneys, stomach, small intestine, brain, and muscle of DN mice were different. The results indicated that the HQD could be used for the treatment of DN and to improve renal function. The pathological state of diabetic nephropathy may affect tissue distribution of HQD active ingredients in mice.

Pharmacokinetic Difference of Six Active Constituents of Huangqi Liuyi Decoction between Control and Diabetic Nephropathy Mouse Models

Huangqi Liuyi decoction is a famous traditional Chinese medicine (TCM) that has been widely used in China for the management of diabetes since the Song Dynasty. Today, it is commonly used for treating diabetic nephropathy (DN). Our previous experimental studies have suggested that the mixture HQD, containing astragalus saponin, astragalus flavone, astragalus polysaccharide, and glycyrrhetinic acid, could be used for the treatment of DN and to improve renal function. The objective of this study was to develop a sensitive and reliable high-performance liquid chromatography-tandem mass spectrometry method for simultaneous quantitation of astragaloside IV, calycosin-7-O-β-D-glucoside, calycosin-glucuronide, ononin, formononetin, and glycyrrhizic acid, which are the main active constituents in HQD, and to compare the pharmacokinetics of these active constituents in control and DN mice orally treated with HQD. The results indicated that the pharmacokinetic parameters of HQD were significantly different between the control and DN mouse groups. The absorption of HQD in the DN mice was greater than that in control mice.

Soluble tumor necrosis factor receptor 2 is associated with progressive diabetic kidney disease in patients with type 2 diabetes mellitus

BACKGROUND

Chronic low-grade inflammation is considered one of the major mechanisms for the progression of diabetic kidney disease. We investigated the prognostic value of circulating soluble tumor necrosis factor receptor 2 (sTNFR2) for early nephropathy in patients with type 2 diabetes.

MATERIALS AND METHODS

A total of 364 patients with type 2 diabetes and an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73m2 were followed up for a median of 4 years. Renal outcomes were defined as a composite of either or both a >30% decline in the eGFR and/or albuminuria stage progression determined with consecutive tests.

RESULTS

Seventy-three patients developed renal composite events. Serum concentrations of sTNFR2 were strongly associated with the risk of renal function decline and progressive changes in albuminuria. Through a receiver operating characteristic curve analysis, a serum sTNFR2 level of 1.608 ng/mL was adopted as the discriminator value for predicting renal outcomes (area under the curve 0.63, 95% confidence interval 0.57-0.70, p < 0.001), yielding a sensitivity of 75.3% and a specificity of 51.2%. The association of sTNFR2 levels ≥1.608 ng/mL to renal outcomes was significant after adjusting for relevant variables (hazard ratio 2.27, 95% confidence interval 1.23-4.20, p = 0.009) and remained consistent across subgroups stratified by age, sex, systolic blood pressure, eGFR, albuminuria, and the use of renin-angiotensin system blockers.

CONCLUSIONS

Higher circulating levels of sTNFR2 are independently associated with an eGFR decline and progressive albuminuria in patients with type 2 diabetes.

Comparison of Nonalbuminuric and Albuminuric Diabetic Kidney Disease Among Patients With Type 2 Diabetes: A Systematic Review and Meta-Analysis

BACKGROUND

Diabetic kidney disease (DKD) is one of most common complications of diabetes. Recently, the classical phenotype of DKD, which is characterized by albuminuria preceding renal insufficiency, has been challenged since a subset of diabetic patients with renal insufficiency but without albuminuria has been increasingly reported. However, the available evidence is inconsistent. Thus, the present systematic review will assess and summarize the available data regarding nonalbuminuric diabetic kidney disease (NADKD).

METHODS

PubMed, Embase, and Cochrane were searched for clinical trials related to NADKD. The results were limited to full-text articles published in English, without restrictions on the publication time. The quality of clinical trials was appraised, and the data were extracted. Meta-analysis was conducted using a random-effects model. Descriptive analysis was performed if the data were insufficient.

RESULTS

A final total of 31 articles were included in this review. The meta-analysis of 18 studies showed that compared with albuminuric DKD, patients with NADKD were older (MD = 1.04 years old, 95% CI [0.52, 1.57], p < 0.05); were more often women (Male RR = 0.74, 95% CI [0.68, 0.81], p < 0.05); had shorter diabetes duration (MD = -2.9 years, 95% CI [-3.63, -2.18], p < 0.05), lower HbA1c levels (MD = -0.34%, 95% CI [-0.42, -0.25], p < 0.05), and lower blood pressure (systolic blood pressure MD = -6.21 mmHg, 95% CI [-9.41, -3.0], p < 0.05; diastolic blood pressure MD = -1.27 mmHg, 95% CI [-2.15, 4.0], p < 0.05); less frequently experienced diabetic retinopathy (RR = 0.58, 95% CI [0.51, 0.67], p < 0.05); and less frequently used renin-angiotensin-aldosterone system (RAAS) inhibitors. The underlying pathology of NADKD might be different from that of the classic phenotype of DKD, which is associated with more advanced tubulointerstitial and vascular lesions but mild typical glomerular lesions. The annual estimated glomerular filtration rate decline tended to be lower in patients with NADKD than in those with albuminuric DKD. The risk for cardiovascular disease, end-stage renal disease, and all-cause death was lower for patients with NADKD than patients with albuminuric DKD.

CONCLUSIONS

The prevalence of NADKD has increased in recent decades, and its characteristics, pathology, and prognosis are different from those of albuminuric DKD; thus, diagnosis and treatment strategies should be different. More attention should be given to this phenotype.

Young adult onset type 2 diabetes versus type 1 diabetes: Progression to and survival on renal replacement therapy

BACKGROUND

Young-onset type 2 diabetes is an aggressive disease characterized by development of diabetic complications, including nephropathy, early in the disease course. However, within the cohort of young-onset type 1 and type 2 diabetes there are limited comparative data regarding progression to ESKD requiring renal replacement therapy or renal-related death (RRT/RRD).

METHODS

Probabilistic linkage of data from the RPAH Diabetes Centre, National Death Index and Australian and New Zealand Dialysis and Transplant Registry was undertaken. Cumulative Incidence Competing Risk and Cox Proportional Hazards Modelling approaches were utilized to examine progression to ESKD in young-onset type 1 and type 2 diabetes (age of diagnosis 15-35 years).

FINDINGS

Unadjusted incidence rates (95% CI) of RRT/RRD in young-onset type 1 and type 2 diabetes were 3.1 (2.3-4.0) and 4.6 (3.7-5.7) per 1000 person years respectively. After adjustment for gender, ethnicity and duration of diabetes, the HR (95% CI) of RRT/RRD in young-onset type 2 diabetes was 2.0 (1.4-2.9). The HR remained higher after further adjustment for first available cholesterol, HbA1c and systolic blood pressure but not BMI. For those who progressed to RRT, prognosis was similar irrespective of diabetes type; cumulative incidence of mortality was 40% in both young-onset type 1 and type 2 diabetes after 6 years of dialysis.

INTERPRETATION

Progression to RRT/RRD is greater in young-onset type 2 diabetes than in young-onset type 1 diabetes. The increased progression is associated with increased BMI. However, once ESKD is reached, individuals with young-onset type 1 and type 2 diabetes do equally poorly.

Renoprotective mechanisms of sodium-glucose co-transporter 2 (SGLT2) inhibitors against the progression of diabetic kidney disease

Sodium-glucose co-transporter 2 inhibitors (SGLT2-Is) have emerged as a promising class of antidiabetic drugs with cardioprotective and renoprotective effects in patients with type 2 diabetes (T2D). The sodium-glucose co-transporters 1 and 2 (SGLT 1 and SGLT2) located in the renal proximal tubules are responsible for glucose reabsorption from the glomerular filtrate back into the systemic circulation. Inhibition of SGLT2, which accounts for about 90% of the glucose reabsorption, leads to a significant reduction in blood glucose levels and a concomitant increase in the urinary excretion of glucose (glycosuria). Multiple mechanisms contribute to the nephroprotective effects of SGLT2-Is in T2D patients. These include: (1) Restoration of the tubuloglomerular feedback by increasing sodium delivery at macula densa, leading to afferent arteriolar constriction and reduced glomerular hyperfiltration, (2) Decreased activation of the intra-renal renin-angiotensin-aldosterone system, which also contributes to reducing glomerular hyperfiltration, (3) Increased production of ketone bodies, which serves as an alternate fuel for adenosine triphosphate production in mitochondria, which helps in attenuating inflammation, and (4) Protection against hypoxia, oxidative stress, and fibrosis. This review elaborates on the key mechanisms that underlie the nephroprotective effects and the adverse effects of SGLT2-Is in T2D patients with progressive diabetic kidney disease.

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

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

The Efficacy of Triptolide in Preventing Diabetic Kidney Diseases: A Systematic Review and Meta-Analysis

Ethnopharmacological Relevance: Triptolide (TP), the primary biologically active ingredient of Tripterygium wilfordii Hook F (TWHF), possesses the potential to solve the shortcomings of TWHF in treating diabetic kidney disease (DKD) in the clinic. Aim of the Study: We conducted a meta-analysis to evaluate the efficacy of TP in treating DKD and offer solid evidence for further clinical applications of TP. Materials and Methods: Eight databases (CNKI, VIP, CBM, WanFang, PubMed, Web of Science, EMBASE, and Cochrane library) were electronically searched for eligible studies until October 17, 2020. We selected animal experimental studies using TP versus renin-angiotensin system inhibitors or nonfunctional liquids to treat DKD by following the inclusion and exclusion criteria. Two researchers independently extracted data from the included studies and assessed the risk of bias with the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias tool. Fixed-effects meta-analyses, subgroup analyses, and meta-regression were conducted using RevMan 5.3 software. Inplasy registration number: INPLASY2020100042. Results: Twenty-six studies were included. Meta-analysis showed that TP significantly reduced albuminuria (14 studies; standardized mean difference SMD: -1.44 [-1.65, -1.23], I2 = 87%), urine albumin/urine creatinine ratio (UACR) (8 studies; SMD: -5.03 [-5.74, -4.33], I2 = 84%), total proteinuria (4 studies; SMD: -3.12 [-3.75, -2.49], I2 = 0%), serum creatinine (18 studies; SMD: -0.30 [-0.49, -0.12], I2 = 76%), and blood urea nitrogen (12 studies; SMD: -0.40 [-0.60, -0.20], I2 value = 55%) in DKD animals, compared to the vehicle control. However, on comparing TP to the renin-angiotensin system (RAS) inhibitors in DKD treatment, there was no marked difference in ameliorating albuminuria (3 studies; SMD: -0.35 [-0.72, 0.02], I2 = 41%), serum creatinine (3 studies; SMD: -0.07 [-0.62, 0.48], I2 = 10%), and blood urea nitrogen (2 studies; SMD: -0.35 [-0.97, 0.28], I2 = 0%). Of note, TP exhibited higher capacities in reducing UACR (2 studies; SMD: -0.66 [-1.31, -0.01], I2 = 0%) and total proteinuria (2 studies; SMD: -1.18 [-1.86, -2049], I2 = 0%). Meta-regression implicated that the efficacy of TP in reducing DKD albuminuria was associated with applied dosages. In addition, publication bias has not been detected on attenuating albuminuria between TP and RAS inhibitors after the diagnosis of DKD. Systematic Review Registration: https://clinicaltrials.gov/, identifier INPLASY2020100042.

C-peptide ameliorates high glucose-induced podocyte dysfunction through the regulation of the Notch and TGF-β signaling pathways

The podocyte is one of the main components of the glomerular filtration barrier in the kidney, and its injury may contribute to proteinuria, glomerulosclerosis and eventually kidney failure. C-peptide, a cleavage product of proinsulin, shows therapeutic potential for treating diabetic nephropathy (DN). The aim of this study was to investigate the effect of C-peptide on high glucose-induced podocyte dysfunction. In the present study, we found that the protective effects of islet transplantation were superior to simple insulin therapy for the treatment of DN in streptozotocin (STZ)-treated rats. And such superiority may due to the function of C-peptide secreted at the implanted site. Based on this background, we determined that the application of C-peptide significantly prevented high glucose-induced podocyte injury by increasing the expression of nephrin and synaptopodin. Meanwhile, C-peptide suppressed high glucose-induced epithelial-mesenchymal transition (EMT) and renal fibrosis via decreasing the expression of snail, vimentin, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF). Moreover, the Notch and transforming growth factor-β (TGF-β) signaling pathways were activated by high glucose, and treatment with C-peptide down-regulated the expression of the Notch signaling molecules Notch 1 and Jagged 1 and the TGF-β signaling molecule TGF-β1. These findings suggested that C-peptide might serve as a novel treatment method for DN and podocyte dysfunction.

Diabetic Nephropathy: Challenges in Pathogenesis, Diagnosis, and Treatment

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. Chronic hyperglycemia and high blood pressure are the main risk factors for the development of DN. In general, screening for microalbuminuria should be performed annually, starting 5 years after diagnosis in type 1 diabetes and at diagnosis and annually thereafter in type 2 diabetes. Standard therapy is blood glucose and blood pressure control using the renin-angiotensin system blockade, targeting A1c < 7%, and <130/80 mmHg. Regression of albuminuria remains an important therapeutic goal. However, there are problems in diagnosis and treatment of nonproteinuric DN (NP-DN), which does not follow the classic pattern of DN. In fact, the prevalence of DN continues to increase, and additional therapy is needed to prevent or ameliorate the condition. In addition to conventional therapies, vitamin D receptor activators, incretin-related drugs, and therapies that target inflammation may also be promising for the prevention of DN progression. This review focuses on the role of inflammation and oxidative stress in the pathogenesis of DN, approaches to diagnosis in classic and NP-DN, and current and emerging therapeutic interventions.

Diabetic Nephropathy - a Review of Risk Factors, Progression, Mechanism, and Dietary Management

Type 2 diabetes mellitus (T2DM) leads to many health problems like diabetic nephropathy (DN). One of the key factors for chronic kidney disease and end-stage renal disease (ESRD) is T2DM. Extensive work is being done to delineate the pathogenesis of DN and to extend possible remedies. This review is intended to understand the nature of DN risk factors, progression, effects of glycemic levels, and stages of DN. We also explored the novel diagnostic and therapeutic approaches for DN such as gene therapy and stem cell treatments.

Management of Kidney Failure in Patients with Diabetes Mellitus: What Are the Best Options?

Diabetic kidney disease (DKD) is the most frequent cause of kidney failure (KF). There are large variations in the incidence rates of kidney replacement therapy (KRT). Late referral to nephrology services has been associated with an increased risk of adverse outcomes. In many countries, when patients reach severely reduced glomerular filtration rate (GFR), they are managed by multidisciplinary teams led by nephrologists. In these clinics, efforts will continue to halt chronic kidney disease (CKD) progression and to prevent cardiovascular mortality and morbidity. In patients with diabetes and severely reduced GFR and KF, treating hyperglycemia is a challenge, since some drugs are contraindicated and most of them require dose adjustments. Even more, a decision-making process will help in deciding whether the patient would prefer comprehensive conservative care or KRT. On many occasions, this decision will be conditioned by diabetes mellitus itself. Effective education should cover the necessary information for the patient and family to answer these questions: 1. Should I go for KRT or not? 2. If the answer is KRT, dialysis and/or transplantation? 3. Dialysis at home or in center? 4. If dialysis at home, peritoneal dialysis or home hemodialysis? 5. If transplantation is desired, discuss the options of whether the donation would be from a living or deceased donor. This review addresses the determinant factors with an impact on DKD, aiming to shed light on the specific needs that arise in the management and recommendations on how to achieve a comprehensive approach to the diabetic patient with chronic kidney disease.

Advances in understanding the innate immune-associated diabetic kidney disease

Millions of human deaths occur annually due to chronic kidney disease, caused by diabetic kidney disease (DKD). Despite having effective drugs controlling the hyperglycemia and high blood pressure, the incidence of DKD is increasing, which indicates the need for the development of novel therapies to control DKD. In this article, we discussed the recent advancements in the basic innate immune mechanisms in renal tissues triggered under the diabetes environment, leading to the pathogenesis and progression of DKD. We also summarized the currently available innate immune molecules-targeting therapies tested against DKD in clinical and preclinical settings, and highlighted additional drug targets that could potentially be employed for the treatment of DKD. The improved understanding of the disease pathogenesis may open avenues for the development of novel therapies to rein in DKD, which consequently, can reduce morbidity and mortality in humans in the future.

Perspectives on the Role of Magnetic Resonance Imaging (MRI) for Noninvasive Evaluation of Diabetic Kidney Disease

Renal magnetic resonance imaging (MRI) techniques are currently in vogue, as they provide in vivo information on renal volume, function, metabolism, perfusion, oxygenation, and microstructural alterations, without the need for exogenous contrast media. New imaging biomarkers can be identified using these tools, which represent a major advance in the understanding and study of the different pathologies affecting the kidney. Diabetic kidney disease (DKD) is one of the most important diseases worldwide due to its high prevalence and impact on public health. However, its multifactorial etiology poses a challenge for both basic and clinical research. Therefore, the use of novel renal MRI techniques is an attractive step forward in the comprehension of DKD, both in its pathogenesis and in its detection and surveillance in the clinical practice. This review article outlines the most promising MRI techniques in the study of DKD, with the purpose of stimulating their clinical translation as possible tools for the diagnosis, follow-up, and monitoring of the clinical impacts of new DKD treatments.

Sexual dimorphism in the progression of type 2 diabetic kidney disease in T2DN rats

Diabetic kidney disease (DKD) is a common complication of diabetes, which frequently leads to end-stage renal failure and increases cardiovascular disease risk. Hyperglycemia promotes renal pathologies such as glomerulosclerosis, tubular hypertrophy, microalbuminuria, and a decline in glomerular filtration rate. Importantly, recent clinical data have demonstrated distinct sexual dimorphism in the pathogenesis of DKD in people with diabetes, which impacts both severity- and age-related risk factors. This study aimed to define sexual dimorphism and renal function in a nonobese type 2 diabetes model with the spontaneous development of advanced diabetic nephropathy (T2DN rats). T2DN rats at 12- and over 48-wk old were used to define disease progression and kidney injury development. We found impaired glucose tolerance and glomerular hyperfiltration in T2DN rats to compare with nondiabetic Wistar control. The T2DN rat displays a significant sexual dimorphism in insulin resistance, plasma cholesterol, renal and glomerular injury, urinary nephrin shedding, and albumin handling. Our results indicate that both male and female T2DN rats developed nonobese type 2 DKD phenotype, where the females had significant protection from the development of severe forms of DKD. Our findings provide further evidence for the T2DN rat strain's effectiveness for studying the multiple facets of DKD.

Sodium-Glucose Cotransporter (SGLT2) inhibitors: A new Era in renovascular protection

Diabetic kidney disease (diabetic nephropathy), one of the most serious renovascular diabetic complication represents the leading cause of chronic kidney disease worldwide and is characterized clinically by impaired renal functional indices, hypertension, systemic and renal hemodynamic changes and pathologically by a spectrum of glomerulotubulointerstitial and vascular lesions. Diabetic nephropathy is initiated by persistent hyperglycemia and glomerular hyperfiltration and, if untreated, progresses to increasing albuminuria, declining glomerular filtration rate (GFR), development of end-stage renal failure (ESRF) and or enhanced risk of poor cardiovascular outcomes. The emergence of sodium glucose co-transporter 2 (SGLT2) inhibitors, a novel class of antidiabetic drugs endowed with a wide range of pleiotropic actions revolutionized care of diabetes and its complications. These drugs reduce major cardiovascular events, heart failure hospitalization, rate of progression of albuminuria, and decline in GFR in both diabetic and non-diabetic patients with preserved or impaired renal function and development of ESRF.

Relationship between serum Dickkopf-1 and albuminuria in patients with type 2 diabetes

BACKGROUND

Diabetic kidney disease is a microvascular complication of diabetes with complex pathogenesis. Wingless signaling-mediated renal fibrosis is associated with diabetic kidney disease. Dickkopf-1, a negative regulator of Wingless, has been proven to participate in renal fibrosis, glucose metabolism, and inflammation. However, whether serum Dickkopf-1 levels are associated with diabetic kidney disease remains unclear.

AIM

To assess the relationship between serum Dickkopf-1 levels and albuminuria in individuals with type 2 diabetes.

METHODS

Seventy-three type 2 diabetes patients and 24 healthy individuals were enrolled in this case-control study. Diabetic individuals were separated into normal albuminuria, microalbuminuria, and macroalbuminuria groups based on their urinary albumin/creatinine ratios (UACRs). Clinical characteristics and metabolic indices were recorded. Serum Dickkopf-1 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

No significant difference in serum Dickkopf-1 levels was found between healthy individuals and the normal albuminuria group. However, the levels in the microalbuminuria group were significantly lower than those in the normal albuminuria group (P = 0.017), and those in the macroalbuminuria group were the lowest. Bivariate analysis revealed that serum Dickkopf-1 levels were positively correlated with hemoglobin A1c level (r = 0.368, P < 0.01) and estimated glomerular filtration rate (r = 0.339, P < 0.01), but negatively correlated with diabetes duration (r = -0.231, P = 0.050), systolic blood pressure (r = -0.369, P = 0.001), serum creatinine level (r = -0.325, P < 0.01), and UACR (r = -0.459, P < 0.01). Multiple and logistic regression showed that serum Dickkopf-1 levels were independently associated with UACR (odds ratio = 0.627, P = 0.021).

CONCLUSION

Serum Dickkopf-1 levels are negatively associated with UACR. Lower serum Dickkopf-1 levels could be a critical risk factor for albuminuria in diabetes.

Genomics, Proteomics and Metabolomics Approaches for Predicting Diabetic Nephropathy in Type 2 Diabetes Mellitus Patients

BACKGROUND

There is a continuous rise in the prevalence of type 2 diabetes mellitus (T2DM) worldwide and most patients are unaware of the presence of this chronic disease at the early stages. T2DM is associated with complications related to long-term damage and failure of multiple organ systems caused by vascular changes associated with glycated end products, oxidative stress, mild inflammation, and neovascularization. Among the most frequent complications of T2DM observed in about 20-40% of T2DM patients is diabetes nephropathy (DN).

METHODS

A literature search was made in view of highlighting the novel applications of genomics, proteomics and metabolomics, as the new prospective strategy for predicting DN in T2DM patients.

RESULTS

The complexity of DN requires a comprehensive and unbiased approach to investigate the main causes of disease and identify the most important mechanisms underlying its development. With the help of evolving throughput technology, rapidly evolving information can now be applied to clinical practice.

DISCUSSION

DN is also the leading cause of end-stage renal disease and comorbidity independent of T2DM. In terms of the comorbidity level, DN has many phenotypes; therefore, timely diagnosis is required to prevent these complications. Currently, urine albumin-to-creatinine ratio and estimated glomerular filtration rate (eGFR) are gold standards for assessing glomerular damage and changes in renal function. However, GFR estimation based on creatinine is limited to hyperfiltration status; therefore, this makes albuminuria and eGFR indicators less reliable for early-stage diagnosis of DN.

CONCLUSION

The combination of genomics, proteomics, and metabolomics assays as suitable biological systems can provide new and deeper insights into the pathogenesis of diabetes, as well as discover prospects for developing suitable and targeted interventions.

Adenosine A2A and A3 Receptors as Targets for the Treatment of Hypertensive-Diabetic Nephropathy

Diabetic nephropathy (DN) and hypertension are prime causes for end-stage renal disease (ESRD) that often coexist in patients, but are seldom studied in combination. Kidney adenosine levels are markedly increased in diabetes, and the expression and function of renal adenosine receptors are altered in experimental diabetes. The aim of this work is to explore the impact of endogenous and exogenous adenosine on the expression/distribution profile of its receptors along the nephron of hypertensive rats with experimentally-induced diabetes. Using spontaneously hypertensive (SHR) rats rendered diabetic with streptozotocin (STZ), we show that treatment of SHR-STZ rats with an agonist of adenosine receptors increases A_2A immunoreactivity in superficial glomeruli (SG), proximal tubule (PCT), and distal tubule (DCT). Differently, treatment of SHR-STZ rats with a xanthinic antagonist of adenosine receptors decreases adenosine A₃ immunoreactivity in SG, PCT, DCT, and collecting duct. There is no difference in the immunoreactivity against the adenosine A₁ and A_2B receptors between the experimental groups. The agonist of adenosine receptors ameliorates renal fibrosis, probably via A_2A receptors, while the antagonist exacerbates it, most likely due to tonic activation of A₃ receptors. The reduction in adenosine A₃ immunoreactivity might be due to receptor downregulation in response to prolonged activation. Altogether, these results suggest an opposite regulation exerted by endogenous and exogenous adenosine upon the expression of its A_2A and A₃ receptors along the nephron of hypertensive diabetic rats, which has a functional impact and should be taken into account when considering novel therapeutic targets for hypertensive-diabetic nephropathy.

Association Between Cannabinoid Receptor-1 Gene Polymorphism and the Risk of Diabetic Nephropathy Among Patients with Type 2 Diabetes Mellitus

Background

The cannabinoid receptor 1 (CNR1) gene polymorphism is reportedly associated with components of metabolic syndrome and coronary artery diseases in patients with type 2 diabetes mellitus (T2DM). We investigated whether the common variant rs10493353 polymorphism is associated with diabetic nephropathy (DN) in T2DM patients.

Patients and Methods

T2DM patients with DN were enrolled as a case group, and patients with only T2DM as a control group. Demographic data and biochemical parameters were collected. The polymerase chain reaction-based restriction fragment length polymorphism technique was used for genotyping. The odds ratio and 90% confidence interval were calculated to assess the association between genotypes and the risk of DN.

Results

In total, 320 T2DM patients and 320 DN patients were enrolled. Compared with T2DM patients, the DN patients have a significantly larger body mass index (BMI), longer duration of disease, and higher proportions of smokers, drinkers, and hypertension. The risk of DN was significantly decreased by genotypes AA (OR=0.39, 95% CI=0.23–0.67) and GA (OR=0.53, 95% CI=0.37–0.75) vs GG (codominant model), GA/AA vs GG (OR=0.49, 95% CI=0.35–0.67; dominant model), AA vs GG/GA (OR=0.47, 95% CI=0.28–0.80; recessive model), and the A allele (OR=0.52, 95% CI=0.40–0.68; allele model). Multiple logistic regressions still show significant levels. Negative interactions were found between gene and clinical parameters, including drinking, smoking, BMI, and hypertension.

Conclusion

The A allele of CNR1 gene rs10493353 may be a protective factor for DN in T2DM patients. The risk factors of DN can affect the protective role of A allele in the progression of DN.

Soluble Tumor Necrosis Factor Receptor Type 1 Levels Exhibit A Stronger Association With Renal Outcomes Than Traditional Risk Factors in Chinese Subjects With Type 2 Diabetes Mellitus

OBJECTIVE

Associations between albuminuria and renal outcomes are inconsistent in patients with type 2 diabetes (T2D). Soluble tumor necrosis factor receptor type 1 (sTNFR1) is involved in declined kidney function and poor renal outcomes but this has not been confirmed among Chinese T2D patients. This study aimed to examine the association of sTNFR1 and renal outcomes in a cohort of these patients.

METHODS

Two hundred and eighty-three Chinese T2D patients were enrolled in a prospective observational study which excluded individuals with estimated glomerular filtration rates (eGFR) <30 mL/min/1.73m2. Composite renal outcomes included either or both a >30% decline in eGFR and worsening albuminuria from consecutive tests of blood/urine during a 3.5-year follow-up.

RESULTS

Higher sTNFR1 levels were associated with impaired renal outcomes. sTNFR1 levels of ≥979 pg/mL yielded the most sensitivity and specific predictions of renal outcomes according to the receiver operating curve (area under the curve 0.68, P<.001; sensitivity 78.3%, specificity 48.9%). Renal events occurred more frequently in subjects with sTNFR1 ≥979 pg/mL than in others (sTNFR1 <979 pg/mL; 29% versus 10%; P<.001 by log-rank test). The association between sTNFR1 ≥979 pg/mL and renal outcomes remained significant after adjustment for relevant covariates (adjusted hazard ratio 2.43, 95% confidence interval 1.18 to 5.02; P = .01) and consistent across subgroups stratified by age, sex, blood pressure, eGFR, albuminuria, and the use of renin-angiotensin system inhibitors.

CONCLUSION

Increased sTNFR1 levels were associated with renal outcomes in Chinese T2D subjects, making sTNFR1 a potential biomarker in diabetic kidney disease.