Pathogenic perspectives for the role of inflammation in diabetic nephropathy. Clin Sci (Lond). 2009;116:479-492. [PMID: 19200057 DOI: 10.1042/cs20080394]

Association of Circulating Markers of Microbial Translocation and Hepatic Inflammation with Liver Injury in Patients with Type 2 Diabetes

BACKGROUND

Virtually the entire spectrum of liver disease is observed in association with type 2 diabetes mellitus (T2DM); indeed, T2DM is now the most common cause of liver disease in the U.S. We conducted a pilot study to investigate the relevance of increased microbial translocation and systemic inflammation in the development of liver injury in patients with T2DM.

METHODS

Patients with T2DM (n = 17) and non-diabetic controls (NDC; n = 11) aged 25-80 yrs. participated in this study. Serum levels of endotoxin, calprotectin, soluble CD14 and CD163, and several inflammatory cytokines were measured. In addition to standard liver injury markers, ALT and AST, novel serum markers of liver injury, keratin 18 (K-18) M30 (apoptosis-associated caspase-cleaved keratin 18), and M65 (soluble keratin 18) were evaluated. Statistical analyses were performed using the Mann-Whitney test to assess differences between study groups. Pearson's correlation analysis was performed to determine the strength of association between two variables using GraphPad Prism 9.5.0 software.

RESULTS

Patients with T2DM had significantly higher levels of sCD14 in comparison to NDC, suggesting an increase in gut permeability, microbial translocation, and monocyte/macrophage activation. Importantly, relevant to the ensuing inflammatory responses, the increase in sCD14 in patients with T2DM was accompanied by a significant increase in sCD163, a marker of hepatic Kupffer cell activation and inflammation. Further, a positive correlation was observed between sCD163 and endotoxin and sCD14 in T2DM patients but not in NDC. In association with these changes, keratin 18 (K-18)-based serum markers (M65 and M30) that reflect hepatocyte death were significantly higher in the T2DM group indicating ongoing liver injury. Notably, both M65 and M30 levels correlated with sCD14 and sCD163, suggesting that immune cell activation and hepatic inflammation may be linked to the development of liver injury in T2DM.

CONCLUSIONS

These findings suggest that the pathogenic changes in the gut-liver axis, marked by increased microbial translocation, may be a major component in the etiology of hepatocyte inflammation and injury in patients with T2DM. However, larger longitudinal studies, including histological evidence, are needed to confirm these observations.

Phloretamide Protects against Diabetic Kidney Damage and Dysfunction in Diabetic Rats by Attenuating Hyperglycemia and Hyperlipidemia, Suppressing NF-κβ, and Upregulating Nrf2

Potent hypoglycemic and antioxidant effects were recently reported for the apple-derived phenolic compound phloretamide (PLTM). The renoprotective effects of this compound are yet to be shown. This study aimed to examine the potential of PLTM to prevent diabetic nephropathy in streptozotocin-induced diabetic rats and to examine the possible mechanisms of protection. Non-diabetic and STZ-diabetic male rats were treated orally by gavage with either the vehicle or with PTLM (200 mg/kg; twice/week) for 12 weeks. PTLM significantly increased urine volume and prevented glomerular and tubular damage and vacuolization in STZ-diabetic rats. It also increased creatinine excretion and reduced urinary albumin levels and the renal levels of kidney injury molecule-1 (KIM-1), 8-hydroxy-2'-deoxyguanosine (8-OHdG), neutrophil gelatinase-associated lipocalin (NGAL), and nephrin in the diabetic rats. PTLM also prevented an increase in the nuclear levels of NF-κβ, as well as the total levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), caspase-3, and Bax in the kidneys of diabetic rats. These effects were associated with reduced serum levels of triglycerides, cholesterol, and low-density lipoprotein cholesterol. In both the control and diabetic rats, PTLM significantly reduced fasting plasma glucose and enhanced the renal mRNA and cytoplasmic levels of Nrf2, as well as the levels of Bcl2, superoxide dismutase (SOD), and glutathione (GSH). However, PTLM failed to alter the cytoplasmic levels of keap1 in diabetic rats. In conclusion, PTLM prevents renal damage and dysfunction in STZ-diabetic rats through its hypoglycemic and hypolipidemic activities, as well as through its antioxidant potential, which is mediated by activating the Nrf2/antioxidant axis.

Effect and pharmacological mechanism of Salvia miltiorrhiza and its characteristic extracts on diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is a severe diabetic microvascular complication with an increasing prevalence rate and lack of effective treatment. Traditional Chinese medicine has been proven to have favorable efficacy on DN, especially Salvia miltiorrhiza Bunge (SM), one of the most critical and conventional herbs in the treatment. Over the past decades, studies have demonstrated that SM is a potential treatment for DN, and the exploration of the underlying mechanism has also received much attention.

AIM OF THIS REVIEW

This review aims to systematically study the efficacy and pharmacological mechanism of SM in the treatment of DN to understand its therapeutic potential more comprehensively.

MATERIALS AND METHODS

Relevant information was sourced from Google Scholar, PubMed, Web of Science, and CNKI databases.

RESULTS

Several clinical trials and systematic reviews have indicated that SM has definite benefits on the kidneys of diabetic patients. And many laboratory studies have further revealed that SM and its characteristic extracts, mainly including salvianolic acids and tanshinones, can exhibit pharmacological activity against DN by the regulation of metabolism, renal hemodynamic, oxidative stress, inflammation, fibrosis, autophagy, et cetera, and several involved signaling pathways, thereby preventing various renal cells from abnormal changes in DN, including endothelial cells, podocytes, epithelial cells, and mesangial cells.

CONCLUSION

As a potential drug for the treatment of DN, SM has multi-component, multi-target, and multi-pathway pharmacological effects. This work will not only verify the satisfactory curative effect of SM in the treatment of DN but also provide helpful insights for the development of new anti-DN drugs and the application of traditional Chinese medicine.

Platelets in Renal Disease

Kidney disease is a major global health concern, affecting millions of people. Nephrologists have shown interest in platelets because of coagulation disorders caused by renal diseases. With a better understanding of platelets, it has been found that these anucleate and abundant blood cells not only play a role in hemostasis, but also have important functions in inflammation and immunity. Platelets are not only affected by kidney disease, but may also contribute to kidney disease progression by mediating inflammation and immune effects. This review summarizes the current evidence regarding platelet abnormalities in renal disease, and the multiple effects of platelets on kidney disease progression. The relationship between platelets and kidney disease is still being explored, and further research can provide mechanistic insights into the relationship between thrombosis, bleeding, and inflammation related to kidney disease, and elucidate targeted therapies for patients with kidney disease.

Immune responses in diabetic nephropathy: Pathogenic mechanisms and therapeutic target

Diabetic nephropathy (DN) is a chronic, inflammatory disease affecting millions of diabetic patients worldwide. DN is associated with proteinuria and progressive slowing of glomerular filtration, which often leads to end-stage kidney diseases. Due to the complexity of this metabolic disorder and lack of clarity about its pathogenesis, it is often more difficult to diagnose and treat than other kidney diseases. Recent studies have highlighted that the immune system can inadvertently contribute to DN pathogenesis. Cells involved in innate and adaptive immune responses can target the kidney due to increased expression of immune-related localization factors. Immune cells then activate a pro-inflammatory response involving the release of autocrine and paracrine factors, which further amplify inflammation and damage the kidney. Consequently, strategies to treat DN by targeting the immune responses are currently under study. In light of the steady rise in DN incidence, this timely review summarizes the latest findings about the role of the immune system in the pathogenesis of DN and discusses promising preclinical and clinical therapies.

Assessment of Serum Free Light Chains as a Marker of Diabetic Nephropathy; A Cross-Sectional Study in the Kumasi Metropolis

Aims

Although traditional tests such as serum urea, creatinine, and microalbuminuria have been widely employed in the diagnosis of diabetic nephropathy, their sensitivity and accuracy are limited because kidney damage precedes the excretion of these biomarkers. This study investigated the role of serum free light chains in the disease manifestation of diabetic nephropathy.

Materials and Methods

Using a cross-sectional design we recruited 107 diabetes mellitus out-patients who visited the Diabetes and Renal Disease Clinics at the Komfo Anokye Teaching Hospital, Manhyia District Hospital, and Suntreso Government Hospital all in Ghana from November 2019 to February 2020. Five (5) mls of blood was collected from each participant and analyzed for fasting blood glucose (FBG) urea, creatinine, immunoglobulin free light chains. Urine samples were obtained and analyzed for albumin. Anthropometric characteristics were also measured. Data were analyzed using descriptive analysis, analysis of variance (ANOVA) test, Tukey HSD post hoc, and Kruskal Wallis test. Chi-squared test was used to examine if there are significant associations with the indicators of interest. In addition, Spearman’s correlation was used to test for associations between appropriate variables. Receiver operating characteristic analysis (ROC) was also performed to assess the diagnostic performance of free light chains.

Results

The mean age of studied participants was 58.2 years (SD: ± 11.1), 63.2% were females and most of the participants were married (63.0%). The mean FBG of the studied participants was 8.0mmol/L (SD: ± 5.86), and the average duration of diabetes mellitus (DM) was 11.88 years (SD: ± 7.96). The median serum Kappa, Lambda, and Kappa: Lambda ratios for the studied participants were 18.51 (15.63-24.18), 12.19(10.84-14.48), and 1.50(1.23-1.86) respectively. A positive correlation was observed between albuminuria and; Kappa (rs=0.132; p=0.209), and Lambda (rs=0.076; p=0.469). However, a negative correlation was observed between albuminuria and K: L ratio (rs=-0.006; p=0.956).

Conclusions

The current study observed an increasing trend in the levels of free light chains and degree of diabetic nephropathy, although not statistically significant. The exploration of serum free light chains as a better marker of diabetic nephropathy showed very promising results but further studies are required to elucidate its predictive value as a diagnostic tool for diabetic nephropathy.

Up-Date on Diabetic Nephropathy

Diabetes is one of the leading causes of kidney disease. Diabetic kidney disease (DKD) is a major cause of end-stage kidney disease (ESKD) worldwide, and it is linked to an increase in cardiovascular (CV) risk. Diabetic nephropathy (DN) increases morbidity and mortality among people living with diabetes. Risk factors for DN are chronic hyperglycemia and high blood pressure; the renin-angiotensin-aldosterone system blockade improves glomerular function and CV risk in these patients. Recently, new antidiabetic drugs, including sodium-glucose transport protein 2 inhibitors and glucagon-like peptide-1 agonists, have demonstrated additional contribution in delaying the progression of kidney disease and enhancing CV outcomes. The therapeutic goal is regression of albuminuria, but an atypical form of non-proteinuric diabetic nephropathy (NP-DN) is also described. In this review, we provide a state-of-the-art evaluation of current treatment strategies and promising emerging treatments.

Multi-omics analyses of 398 foxtail millet accessions reveal genomic regions associated with domestication, metabolite traits, and anti-inflammatory effects

Foxtail millet (Setaria italica), which was domesticated from the wild species green foxtail (Setaria viridis), is a rich source of phytonutrients for humans. To evaluate how breeding changed the metabolome of foxtail millet grains, we generated and analyzed the datasets encompassing the genomes, transcriptomes, metabolomes, and anti-inflammatory indices from 398 foxtail millet accessions. We identified hundreds of common variants that influence numerous secondary metabolites. We observed tremendous differences in natural variations of the metabolites and their underlying genetic architectures between distinct sub-groups of foxtail millet. Furthermore, we found that the selection of the gene alleles associated with yellow grains led to altered profiles of metabolites such as carotenoids and endogenous phytohormones. Using CRISPR-mediated genome editing we validated the function of PHYTOENE SYNTHASE 1 (PSY1) gene in affecting millet grain color and quality. Interestingly, our in vitro cell inflammation assays showed that 83 metabolites in millet grains have anti-inflammatory effects. Taken together, our multi-omics study illustrates how the breeding history of foxtail millet has shaped its metabolite profile. The datasets we generated in this study also provide important resources for further understanding how millet grain quality is affected by different metabolites, laying the foundations for future millet genetic research and metabolome-assisted improvement.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Correlations between Kidney and Heart Function Bioindicators and the Expressions of Toll-Like, ACE2, and NRP-1 Receptors in COVID-19

BACKGROUND

COVID-19 impacts the cardiovascular system resulting in myocardial damage, and also affects the kidneys leading to renal dysfunction. This effect is mostly through the binding with angiotensin-converting enzyme 2 (ACE2) and Neuropilin-1 (NRP-l) receptors. Toll-Like Receptors (TLRs) typically combine with microbial pathogens and provoke an inflammatory response.

AIM

This work aims to compare the changes in kidney and heart function bioindicators and expressions of TLRs (TLR2 and TLR2) as well as ACE2 and NRP-l receptors in moderate and severe COVID-19 patients. The correlations between kidney and heart function bioindicators and expressions of these receptors are also studied.

PATIENTS AND METHODS

In this study, 50 healthy control and 100 COVID-19 patients (55 males and 45 females) were enrolled. According to WHO guidelines, these participants were divided into severe (50 cases) and moderate (50 cases). Serum creatinine, blood urea, CK-MB, LDH, and Troponin I were estimated. We measured the gene expression for Toll-Like Receptors (TLR2 and TLR4), ACE2, and NRP-1 in the blood samples using quantitative real-time PCR (qRT-PCR).

RESULTS

In comparison with the healthy group, all patients exhibited a significant elevation in serum creatinine, urea, cardiac enzymes (CK-MB and LDH), and CRP. Serum Troponin I level was significantly increased in severe COVID-19 patients. Furthermore, all studied patients revealed a significant elevation in the expression levels of TLR2, TLR4, ACE2, and NRP-1 mRNA. In all patients, CK-MB, ACE2, and NRP-1 mRNA expression levels were positively correlated with both TLR2 and TLR4 expression levels. Moreover, serum creatinine and urea levels were positively correlated with both TLR2 and TLR 4 expression levels in the severe group only. In the moderate group, serum CK-MB activity and Troponin I level had a significant positive correlation with both NRP-1 and ACE2 expression levels, while serum urea level and LDH activity had a significant positive correlation with NRP-1 only. In severe patients, the increases in serum creatinine, urea, CK-MB, and LDH were significantly associated with the elevations in both ACE2 and NRP-1 expression levels, whereas serum Troponin I level had a positive direct relationship with NRP-1 only.

CONCLUSIONS

Our study concluded that expression levels for TLR2, TLR4, ACE2, and NRP-1 mRNA in both severe and moderate patients were positively correlated with renal biomarkers and cardiac enzymes. Innate immune markers can be important because they correlate with the severity of illness in COVID-19.

Maresin 1 Alleviates Diabetic Kidney Disease via LGR6-Mediated cAMP-SOD2-ROS Pathway

BACKGROUND

Chronic hyperglycemia-induced inflammation is recognized as the most important pathophysiological process in diabetic kidney disease (DKD). As maresin 1 (MaR1) is an extensive anti-inflammatory lipid mediator, the present study investigated the protective role of MaR1 in the pathogenesis of DKD and its clinical relevance.

METHODS

Serum MaR1 concentrations were analyzed in 104 subjects with normal glucose tolerant, type 2 diabetes (T2DM), or DKD. Streptozotocin (STZ) together with high fat diet was used to induce male C57BL/6 J mice into diabetic mice which were treated with MaR1. Human renal tubule epithelial cells (HK-2 cells) were treated by high glucose for glucotoxicity cell model and transfected with LGR6 siRNA for knockdown with MaR1 added，and detected oxidative stress and inflammatory related factors.

RESULTS

Serum MaR1 concentrations were significant decreased in T2DM with or without kidney disease compared with normal participant and were lowest in patients with DKD. Serum MaR1 concentrations were negatively correlated with hemoglobin A1c (HbA1c), duration of diabetes, urinary albumin to creatinine ratio (UACR), neutrophil, and neutrophil-lymphocyte ratio and were positively correlated with high-density lipoprotein-cholesterol (HDL-C) and estimated glomerular filtration rate (eGFR). In mouse model, MaR1 injection alleviated hyperglycemia, UACR and the pathological progression of DKD. Interestingly, the renal expression of LGR6 was down-regulated in DKD and high glucose treated HK-2 cells but up-regulated by MaR1 treatment. Mechanistically, MaR1 alleviated inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway in DKD mice and high glucose treated HK-2 cells.

CONCLUSIONS

Our study demonstrates that decreased serum MaR1 levels were correlated with the development of DKD. MaR1 could alleviate DKD and glucotoxicity-induced inflammation via LGR6-mediated cAMP-SOD2 antioxidant pathway. Thus, our present findings identify MaR1 as a predictor and a potential therapeutic target for DKD.

Gut microbiota and diabetic kidney diseases: Pathogenesis and therapeutic perspectives

Diabetic kidney disease (DKD) is one of the major chronic complications of diabetes mellitus (DM), as well as a main cause of end-stage renal disease. Over the last few years, substantial research studies have revealed a contributory role of gut microbiota in the process of DM and DKD. Metabolites of gut microbiota like lipopolysaccharide, short-chain fatty acids, and trimethylamine N-oxide are key mediators of microbial–host crosstalk. However, the underlying mechanisms of how gut microbiota influences the onset and progression of DKD are relatively unknown. Besides, strategies to remodel the composition of gut microbiota or to reduce the metabolites of microbiota have been found recently, representing a new potential remedial target for DKD. In this mini-review, we will address the possible contribution of the gut microbiota in the pathogenesis of DKD and its role as a therapeutic target.

Therapeutic potential of mangiferin against kidney disorders and its mechanism of action: A review

There is a swing in research developments concerning the utilization of natural products as effective pharmacotherapeutic agents due to their comparatively lower toxicities than synthetic compounds. Among natural products, mangiferin is a natural C-glucosyl xanthonoid polyphenol with remarkable pharmacological activities. Emerging evidence indicates the therapeutic benefits of mangiferin against various kidney disorders, including renal injury, diabetic nephropathy, renal fibrosis, hyperuricemic nephropathy, and lupus nephritis, in experimental animal models. The mangiferin induced antioxidant response resulting in vital functions, such as protection against renal inflammation, inhibits renal cell apoptosis, activates autophagy, causes immunomodulation, regulates renal urate transporters and modulates cell signalling pathways. The purpose of this review provide a brief overview of the in vitro/in vivo reno-protective effect of mangiferin and the underlying mechanism(s) in protecting against kidney disorders. Understanding the pharmacological actions of mangiferin is prominence due to its excellent therapeutic potential in managing kidney disorders. Thus, in addition to this review, in-silico molecular docking is performed against nuclear factor kappa B (NF-κB) and soluble epoxide hydrolase (sEH) to study the mechanism of action of mangiferin. It is believed that mangiferin is a safe reno-protective molecule. The observed positive effects are attributed to the inhibition of inflammation caused by NF-κB and sEH upregulation and oxidative stress activation. Studies on the efficacy and safety of mangiferin in clinical trials are further warranted to confirm its medicinal potential as therapeutic agent for kidney disorders in humans.

Activation of Transcription Factor EB Alleviates Tubular Epithelial Cell Injury via Restoring Lysosomal Homeostasis in Diabetic Nephropathy

Disruption of lysosomal homeostasis contributes to the tubulopathy of diabetic nephropathy; however, its underlying mechanisms remain unclear. Herein, we report that decreased activity of transcription factor EB (TFEB) is responsible for the disturbed lysosome biogenesis and clearance in this pathological process. This was confirmed by the findings that insufficient lysosomal replenishment and damaged lysosomal clearance coincided with TFEB inactivation, which was mediated by mTOR hyperactivation in the renal tubular epithelial cells (TECs) of diabetic nephropathy. Furthermore, either TFEB overexpression or pharmacological activation of TFEB enhanced lysosomal clearance via promoting lysosomal biogenesis and protected TECs by reducing apoptosis in vitro. In addition, pharmacological activation of TFEB attenuated renal tubule injury, apoptosis, and inflammation in db/db mice. In conclusion, diabetes-induced mTOR activation represses TFEB function, thereby perturbing lysosomal homeostasis through impairing lysosomal biogenesis and clearance in TECs. Moreover, TFEB activation protects TECs from diabetic injuries via restoring lysosomal homeostasis.

The Multiple Roles of Fibroblast Growth Factor in Diabetic Nephropathy

Diabetic nephropathy (DN) is a common microvascular complication in the late stages of diabetes. Currently, the etiology and pathogenesis of DN are not well understood. Even so, available evidence shows its development is associated with metabolism, oxidative stress, cytokine interaction, genetic factors, and renal microvascular disease. Diabetic nephropathy can lead to proteinuria, edema and hypertension, among other complications. In severe cases, it can cause life-threatening complications such as renal failure. Patients with type 1 diabetes, hypertension, high protein intake, and smokers have a higher risk of developing DN. Fibroblast growth factor (FGF) regulates several human processes essential for normal development. Even though FGF has been implicated in the pathological development of DN, the underlying mechanisms are not well understood. This review summarizes the role of FGF in the development of DN. Moreover, the association of FGF with metabolism, inflammation, oxidative stress and fibrosis in the context of DN is discussed. Findings of this review are expected to deepen our understanding of DN and generate ideas for developing effective prevention and treatments for the disease.

Saxagliptin protects against diabetic nephropathy by inhibiting caspase 3/PARP-1-dependent nephrocyte apoptosis

Saxagliptin (SAX) can protect against tissue damage caused by diabetic nephropathy. However, whether this compound can restore kidney function, and its specific mechanism of action remain unclear. The present study explored the therapeutic effects and mechanisms of SAX. Male Wistar rats (8 weeks old) were randomly divided into the following groups: A control group (n=10); a group with streptozocin-induced diabetes mellitus (DM) treated with saline (n=20); and a group with streptozocin-induced DM treated with SAX (n=20). Following 20 weeks of treatment, renal function and the extent of renal damage were assessed based on histological staining using hematoxylin and eosin, periodic acid-Schiff and Masson's trichrome staining. The experimental results indicated that Streptozocin induction of DM led to thicker basement membranes in mesangial cells and a more abundant extracellular matrix. These changes were ameliorated following treatment with SAX. The data demonstrated that renal tissue and renal cell apoptosis were ameliorated significantly following treatment with SAX. Furthermore, the expression levels of the apoptotic genes poly (ADP-ribose) polymerase-1 (PARP-1) and caspase 3 were significantly decreased following treatment with SAX. Therefore, SAX may reduce the extent of renal apoptosis and pathological outcomes in diabetic nephropathy by downregulating the expression of caspase 3 and PARP-1 in the death receptor pathway of apoptosis.

Hyperoside Protects HK-2 Cells Against High Glucose-Induced Apoptosis and Inflammation via the miR-499a-5p/NRIP1 Pathway

Hyperoside, a flavonol glycoside, is derived from plants of the genera Hypericum and Crataegus. Recent studies have indicated the anti-apoptotic and anti-inflammatory roles of hyperoside. The present study was designed to measure the effects of hyperoside on high glucose (HG)-treated HK-2 cells. HK-2 is a human papillomavirus 16 transformed cell line and can be used as a model for normal tubular cell. Cell apoptosis was examined by TUNEL assays and flow cytometry analysis. Inflammatory response was detected by Enzyme linked immunosorbent assay kits. Western blotting was applied to detect protein levels of apoptosis-related genes and inflammatory cytokines. Mechanistical assays including luciferase reporter and RNA pull down assays were applied to detect the binding relationship between molecules. We identified that hyperoside protected HK-2 cells against HG-induced apoptosis and inflammation. Moreover, miR-499a-5p was upregulated by hyperoside in a dose dependent manner. MiR-499a-5p inhibition rescued the suppressive effects of hyperoside on apoptosis and inflammation of HG-treated HK-2 cells. Furthermore, miR-499a-5p targeted NRIP1 to inhibit its mRNA expression, and further suppressed its translation. NRIP1 was downregulated by hyperoside in a dose dependent manner. Finally, rescue assays indicated that miR-499a-5p inhibition rescued the protective effects of hyperoside on apoptosis and inflammatory response of HK-2 cells by NRIP1. In conclusion, our findings revealed that hyperoside alleviates HG-induced apoptosis and inflammatory response of HK-2 cells by the miR-499a-5p/NRIP1 axis.

MiR-770-5p facilitates podocyte apoptosis and inflammation in diabetic nephropathy by targeting TIMP3

OBJECTIVE

Diabetic nephropathy (DN) is one of the most severe and frequent diabetic complications. MicroRNAs (miRNAs) have been reported to play a vital role in DN pathogenesis. The present study aimed to investigate the molecular mechanism of miR-770-5p in DN.

METHODS

Podocyte injury model was established by treating mouse podocytes with high glucose (HG, 33 mM) for 24 h. The levels of miR-770-5p and TIMP3 were examined in kidney tissues and podocytes using quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was applied to detect apoptosis in podocytes. Western blot assay was used to measure the protein levels of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax) and tissue inhibitors of metalloproteinase 3 (TIMP3). Enzyme-linked immunosorbent assay (ELISA) was conducted to measure the levels of inflammatory factors. The interaction between miR-770-5p and TIMP3 was determined by MicroT-CDS and luciferase reporter assay.

RESULTS

MiR-770-5p was up-regulated and TIMP3 was down-regulated in DN kidney tissues and HG-stimulated podocytes. Depletion of miR-770-5p suppressed cell apoptosis and the release of pro-inflammatory factors in HG-treated podocytes. Additionally, TIMP3 was a target of miR-770-5p in HG-treated podocytes. TIMP3 inhibited cell apoptosis and inflammation in HG-treated podocytes. Moreover, TIMP3 knockdown alleviated the inhibitory effect of miR-770-5p silencing on podocyte apoptosis and inflammatory response.

CONCLUSION

Knockdown of miR-770-5p suppressed podocyte apoptosis and inflammatory response by targeting TIMP3 in HG-treated podocytes, indicating that miR-770-5p may be a potential therapeutic target for DN therapy.

Presence and activation of pro-inflammatory macrophages are associated with CRYAB expression in vitro and after peripheral nerve injury

BACKGROUND

Inflammation constitutes both positive and negative aspects to recovery following peripheral nerve injury. Following damage to the peripheral nervous system (PNS), immune cells such as macrophages play a beneficial role in creating a supportive environment for regrowing axons by phagocytosing myelin and axonal debris. However, a prolonged inflammatory response after peripheral nerve injury has been implicated in the pathogenesis of negative symptoms like neuropathic pain. Therefore, the post-injury inflammation must be carefully controlled to prevent secondary damage while allowing for regeneration. CRYAB (also known as alphaB-crystallin/HSPB5) is a small heat shock protein that has many protective functions including an immunomodulatory role in mouse models of multiple sclerosis, spinal cord injury, and stroke. Because its expression wanes and rebounds in the early and late periods respectively after PNS damage, and CRYAB null mice with sciatic nerve crush injury display symptoms of pain, we investigated whether CRYAB is involved in the immune response following PNS injury.

METHODS

Sciatic nerve crush injuries were performed in age-matched Cryab knockout (Cryab-/-) and wildtype (WT) female mice. Nerve segments distal to the injury site were processed by immunohistochemistry for macrophages and myelin while protein lysates of the nerves were analyzed for cytokines and chemokines using Luminex and enzyme-linked immunosorbent assay (ELISA). Peritoneal macrophages from the two genotypes were also cultured and polarized into pro-inflammatory or anti-inflammatory phenotypes where their supernatants were analyzed for cytokines and chemokines by ELISA and protein lysates for macrophage antigen presenting markers using western blotting.

RESULTS

We report that (1) more pro-inflammatory CD16/32+ macrophages are present in the nerves of Cryab-/- mice at days 14 and 21 after sciatic nerve crush-injury compared to WT counterparts, and (2) CRYAB has an immunosuppressive effect on cytokine secretion [interleukin (IL)-β, IL-6, IL-12p40, tumor necrosis factor (TNF)-α] from pro-inflammatory macrophages in vitro.

CONCLUSIONS

CRYAB may play a role in curbing the potentially detrimental pro-inflammatory macrophage response during the late stages of peripheral nerve regeneration.

MicroRNA-140-5p ameliorates the high glucose-induced apoptosis and inflammation through suppressing TLR4/NF-κB signaling pathway in human renal tubular epithelial cells

Hyperglycemia-induced renal tubular cell injury is thought to play a critical role in the pathogenesis of diabetic nephropathy (DN). However, the role of miRNAs in renal tubular cell injury remains to be fully elucidated. The aim of the present study was to investigate the role and mechanisms of miRNAs protecting against high glucose (HG)-induced apoptosis and inflammation in renal tubular cells. First, we analyzed microRNA (miRNA) expression profiles in kidney tissues from DN patients using miRNA microarray. It was observed that miRNA-140-5p (miR-140-5p) was significantly down-regulated in kidney tissues from patients with DN. An inverse correlation between miR-140-5p expression levels with serum proteinuria was observed in DN patients, suggesting miR-140-5p may be involved in the progression of DN. HG-induced injury in HK-2 cells was used to explore the potential role of miR-140-5p in DN. We found that miR-140-5p overexpression improved HG-induced cell injury, as evidenced by the enhancement of cell viability, and inhibition of the activity of caspase-3 and reactive oxygen species (ROS) generation. It was also observed that up-regulation of miR-140-5p suppressed HG induced the expressions of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in HK-2 cells. In addition, TLR4, one of the upstream molecules of NF-κB signaling pathway, was found to be a direct target of miR-140-5p in the HK-2. Moreover, the HG-induced activation of NF-κB signaling pathway was inhibited by miR-140-5p overexpression. These results indicated that miR-140-5p protected HK-2 cells against HG-induced injury through blocking the TLR4/NF-κB pathway, and miR-140-5p may be considered as a potential prognostic biomarker and therapeutic target in the treatment of DN.

Inhibition of miRNA-155 Alleviates High Glucose-Induced Podocyte Inflammation by Targeting SIRT1 in Diabetic Mice

OBJECTIVE

Microinflammation plays a crucial role in podocyte dysfunction in diabetic nephropathy, but its regulatory mechanism is still unclear. This study is aimed at discussing the mechanisms underlying the effect of miRNA-155 on podocyte injury to determine its potential as a therapeutic target.

METHODS

Cultured immortalized mouse podocytes and diabetic KK-Ay mice models were treated with a miR-155 inhibitor. Western blotting, real-time PCR, ELISA, immunofluorescence, and Luciferase reporter assay were used to analyze markers of inflammation cytokines and podocyte injury.

RESULTS

miRNA-155 was found to be highly expressed in serum and kidney tissue of mice with diabetic nephropathy and in cultured podocytes, accompanied by elevated levels of inflammatory factors. Inhibition of miRNA-155 can reduce proteinuria and ACR levels, diminish the secretion of inflammatory molecules, improve kidney function, inhibit podocyte foot fusion, and reverse renal pathological changes in diabetic nephropathy mice. Overexpression of miRNA-155 in vitro can increase inflammatory molecule production in podocytes and aggravates podocyte injury, while miRNA-155 inhibition suppresses inflammatory molecule production in podocytes and reduces podocyte injury. A luciferase assay confirmed that miRNA-155 could selectively bind to 3'-UTR of SIRT1, resulting in decreased SIRT1 expression. In addition, SIRT1 siRNA could offset SIRT1 upregulation and enhance inflammatory factor secretion in podocytes, induced by the miRNA-155 inhibitor.

CONCLUSIONS

These findings strongly support the hypothesis that miRNA-155 inhibits podocyte inflammation and reduces podocyte injury through SIRT1 silencing. miRNA-155 suppression therapy may be useful for the management of diabetic nephropathy.

Urinary calprotectin, NGAL, and KIM-1 in the differentiation of primarily inflammatory vs. non-inflammatory stable chronic kidney diseases

Introduction

It has been demonstrated that urinary neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin are helpful biomarkers in the differentiation of intrinsic and prerenal acute kidney injury.

Objective

The present cross-sectional study investigates, whether urinary biomarkers are able to differentiate primarily inflammatory from non-inflammatory entities in chronic kidney disease (CKD).

Methods

Urinary calprotectin, NGAL, and kidney injury molecule-1 (KIM-1) concentrations were assessed in a study population of 143 patients with stable CKD and 29 healthy controls. Stable renal function was defined as an eGFR fluctuation ≤5 ml/min/1.73 m² in the past 12 months. Pyuria, metastatic carcinoma, and renal transplantation were regarded as exclusion criteria. Diabetic nephropathy, hypertensive nephropathy, and polycystic kidney disease were categorized as ‘primarily non-inflammatory renal diseases’ (NIRD), whereas glomerulonephritis and vasculitis were regarded as ‘primarily inflammatory renal diseases’ (IRD).

Results

Urinary calprotectin and NGAL concentrations significantly differed between CKD and healthy controls (p < 0.05 each), whereas KIM-1 concentrations did not (p = 0.84). The three biomarkers did neither show significant differences in-between the individual entities, nor the two categories of IRD vs. NIRD (calprotectin 155.7 vs. 96.99 ng/ml; NGAL 14 896 vs. 11 977 pg/ml; KIM-1 1388 vs. 1009 pg/ml; p > 0.05 each). Albumin exceeds the diagnostic power of the investigated biomarkers by far.

Conclusions

The urinary biomarkers calprotectin, NGAL, and KIM-1 have no diagnostic value in the differentiation of primarily inflammatory vs. non-inflammatory etiologies of CKD.

Epidermal Growth Factor Receptor: A Potential Therapeutic Target for Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease worldwide and the major cause of renal failure among patients on hemodialysis. Numerous studies have demonstrated that transient activation of epidermal growth factor receptor (EGFR) pathway is required for promoting kidney recovery from acute injury whereas its persistent activation is involved in the progression of various chronic kidney diseases including DKD. EGFR-mediated pathogenesis of DKD is involved in hemodynamic alteration, metabolic disturbance, inflammatory response and parenchymal cellular dysfunction. Therapeutic intervention of this receptor has been available in the oncology setting. Targeting EGFR might also hold a therapeutic potential for DKD. Here we review the functional role of EGFR in the development of DKD, mechanisms involved and the perspective about use of EGFR inhibitors as a treatment for DKD.

Wogonin Ameliorates Renal Inflammation and Fibrosis by Inhibiting NF-κB and TGF-β1/Smad3 Signaling Pathways in Diabetic Nephropathy

Introduction

Diabetic nephropathy (DN) has become an increasing threat to health, and inflammation and fibrosis play important roles in its progression. Wogonin, a flavonoid, has been proven to suppress inflammation and fibrosis in various diseases, including acute kidney injury. This study aimed at investigating the effect of wogonin on diabetes-induced renal inflammation and fibrosis.

Materials and Methods

Streptozotocin (STZ)-induced diabetic mouse models received gavage doses of wogonin (10, 20, and 40 mg/kg) for 12 weeks. Metabolic indices from blood and urine and pathological damage of glomerulus in the diabetic model were assessed. Glomerular mesangial cells SV40 were cultured in high glucose (HG) medium containing wogonin at concentrations of 1.5825, 3.125, and 6.25 μg/mL for 24 h. Inflammation and fibrosis indices were evaluated by histopathological, Western blotting, and PCR analyses.

Results

Wogonin treatment ameliorated albuminuria and histopathological lesions in diabetic mice. Inflammatory cytokines, such as monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and related signaling pathway NF-κB were downregulated after the administration of wogonin in vivo and in vitro. Furthermore, wogonin reduced the expression of extracellular matrix (ECM), including fibronectin (FN), collagen IV (Col-IV), α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) in the kidneys of diabetic mice and HG-induced mesangial cells. Moreover, the inhibition of TGF-β1/Smad3 pathway might be responsible for these changes.

Conclusion

Wogonin may ameliorate renal inflammation and fibrosis in diabetic nephropathy by inhibiting the NF-κB and TGF-β1/Smad3 signaling pathways.

Oxidative Stress Markers in Chronic Kidney Disease with Emphasis on Diabetic Nephropathy

Diabetes prevalence is increasing worldwide, especially through the increase of type 2 diabetes. Diabetic nephropathy occurs in up to 40% of diabetic patients and is the leading cause of end-stage renal disease. Various factors affect the development and progression of diabetic nephropathy. Hyperglycaemia increases free radical production, resulting in oxidative stress, which plays an important role in the pathogenesis of diabetic nephropathy. Free radicals have a short half-life and are difficult to measure. In contrast, oxidation products, including lipid peroxidation, protein oxidation, and nucleic acid oxidation, have longer lifetimes and are used to evaluate oxidative stress. In recent years, different oxidative stress biomarkers associated with diabetic nephropathy have been found. This review summarises current evidence of oxidative stress biomarkers in patients with diabetic nephropathy. Although some of them are promising, they cannot replace currently used clinical biomarkers (eGFR, proteinuria) in the development and progression of diabetic nephropathy.

Sauchinone Protects Renal Mesangial Cell Dysfunction against Angiotensin II by Improving Renal Fibrosis and Inflammation

Abnormal and excessive growth of mesangial cells is important in the pathophysiologic processes of diabetes-associated interstitial fibrosis and glomerulosclerosis, leading to diabetic nephropathy, which eventually turns into end-stage renal disease. Sauchinone, a biologically-active lignan isolated from aerial parts of Saururus chinensis, has anti-inflammatory and anti-viral activities effects on various cell types. However, there are no studies reporting the effects of sauchinone on diabetic nephropathy. The present study aims to investigate the role of sauchinone in mesangial cell proliferation and fibrosis induced by angiotensin II, as well as the underlying mechanisms of these processes. Human renal mesangial cells were induced by angiotensin II (AngII, 10 μM) in the presence or absence of sauchinone (0.1-1 μM) and incubated for 48 h. In this study, we found that AngII induced mesangial cell proliferation, while treatment with sauchinone inhibited the cell proliferation in a dose-dependent manner. Pre-treatment with sauchinone induced down-regulation of cyclins/CDKs and up-regulation of CDK inhibitor, p21, and p27kip1 expression. In addition, AngII-enhanced expression of fibrosis biomarkers such as fibronectin, collagen IV, and connective tissue growth factor (CTGF), which was markedly attenuated by sauchinone. Sauchinone also decreased AngII-induced TGF-β1 and Smad-2, Smad-3, and Smad-4 expression. This study further revealed that sauchinone ameliorated AngII-induced mesangial inflammation through disturbing activation of inflammatory factors, and NLRP3 inflammasome, which is composed of the NLRP3 protein, procaspase-1, and apoptosis-associated speck-like protein containing a CARD (ASC). Moreover, pretreatment of sauchinone inhibited NF-κB translocation and ROS production in AngII-exposed mesangial cells. These data suggest that sauchinone has a protective effect on renal proliferation, fibrosis and inflammation. Therefore, sauchinone might be a potential pharmacological agent in prevention of AngII-induced renal damage leading to diabetic nephropathy.

Metformin inhibits extracellular matrix accumulation, inflammation and proliferation of mesangial cells in diabetic nephropathy by regulating H19/miR-143-3p/TGF-β1 axis

OBJECTIVES

Metformin (MET) has protective effect on diabetic nephropathy (DN). This study aims to demystify the mechanism of MET function in DN.

METHODS

Mouse glomerular membrane epithelial cell line SV40-MES-13 was treated with normal or high glucose combined with or without MET. The relationships among H19, miR-143-3p and TGF-β1 were evaluated by luciferase reporter assay. MTT assay was performed to detect cell proliferation. The levels of inflammatory factors were investigated by enzyme-linked immunosorbent assay. Quantitative real-time PCR and western blot were performed to examine gene and protein expression.

KEY FINDINGS

H19 was up-regulated in the SV40-MES-13 cells after treated with high glucose, which was effectively repressed by MET treatment. MET promoted extracellular matrix accumulation, inflammation and proliferation in the SV40-MES-13 cells after treated with high glucose. These influences conferred by MET were abolished by H19 overexpression. H19 regulated TGF-β1 expression by sponging miR-143-3p. Furthermore, MET inhibited extracellular matrix accumulation, inflammation and proliferation by regulating H19/miR-143-3p/TGF-β1 axis.

CONCLUSIONS

Our studies demonstrated that the protective effect of MET on DN was attributed to the inhibition of proliferation, inflammation and ECM accumulation in mesangial cells via H19/miR-143-3p/TGF-β1 axis, which suggested that the H19/miR-143-3p/TGF-β1 axis could be a valuable target for DN therapies.

Role of the Nox4/AMPK/mTOR signaling axe in adipose inflammation-induced kidney injury

Diabetic kidney disease is one of the most serious complications of diabetes worldwide and is the leading cause of end-stage renal disease. While research has primarily focused on hyperglycemia as a key player in the pathophysiology of diabetic complications, recently, increasing evidence have underlined the role of adipose inflammation in modulating the development and/or progression of diabetic kidney disease. This review focuses on how adipose inflammation contribute to diabetic kidney disease. Furthermore, it discusses in detail the underlying mechanisms of adipose inflammation, including pro-inflammatory cytokines, oxidative stress, and AMPK/mTOR signaling pathway and critically describes their role in diabetic kidney disease. This in-depth understanding of adipose inflammation and its impact on diabetic kidney disease highlights the need for novel interventions in the treatment of diabetic complications.

Ophiopogonin D of Ophiopogon japonicus ameliorates renal function by suppressing oxidative stress and inflammatory response in streptozotocin-induced diabetic nephropathy rats

Ophiopogonin D (OP-D) is the principal pharmacologically active ingredient from Ophiopogon japonicas, which has been demonstrated to have numerous pharmacological activities. However, its protective effect against renal damage in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats remains unclear. The present study was performed to investigate the protective effect of OP-D in the STZ-induced DN rat model. DN rats showed renal dysfunction, as evidenced by decreased serum albumin and creatinine clearance, along with increases in serum creatinine, blood urea nitrogen, TGF-β1, and kidney hypertrophy, and these were reversed by OP-D. In addition, STZ induced oxidative damage and inflammatory response in diabetic kidney tissue. These abnormalities were reversed by OP-D treatment. The findings obtained in the present study indicated that OP-D might possess the potential to be a therapeutic agent against DN via inhibiting renal inflammation and oxidative stress.

Coumarin glycosides from Hydrangea paniculata slow down the progression of diabetic nephropathy by targeting Nrf2 anti-oxidation and smad2/3-mediated profibrosis

BACKGROUND

Water extract of Hydrangea paniculata (HP) stem, rich in coumarin glycosides, has been demonstrated to have renal protective effect in several experimental kidney injury animal models. Currently, it is under pre-clinical development as a class 5 herbal drug against membranous nephropathy. However, whether it also benefits diabetic nephropathy (DN) is not clear.

PURPOSE

This study was performed to investigate the protective effect of HP on streptozotocin-induced experimental DN, and further understand its molecular mechanisms.

METHODS

In the present study, type 1 diabetes rat model was established by the intraperitoneal injection of streptozotocin. HP was orally administered every day for three months. Biochemical analysis and histopathological staining were conducted to evaluate the renal functions. In vivo pharmacokinetic study was conducted to analyse the metabolites of HP with high blood drug concentration. In vitro assay using these metabolites was performed to analyse their ability to reduce reactive oxygen species (ROS) production induced under high glucose (HG) condition by flow cytometry. Reverse transcription-polymerase chain reaction was conducted to analyse the mRNA level of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and IL6 and western blot was performed to analyse the phosphorylation status of smad 2/3 in HK2 cells under TGFβ1 stimulation.

RESULTS

The treatment with HP significantly reduced the blood urea nitrogen and serum creatinine content, and urine albumin excretion in diabetic rats, and increased the creatinine clearance rate. Periodic acid-schiff and methenamine staining and immunohistochemistry revealed that HP also ameliorated glomerulosclerosis and tubular vacuolar degeneration, as well as the deposition of fibronectin and collagen IV in the glomeruli. Pharmacokinetic study results revealed that the major coumarin compounds from HP were metabolised into umbelliferone and esculetin. By in vitro assay, umbelliferone and esculetin were found to significantly decrease ROS production induced by HG content, as well as increase the mRNA level of Nrf2. HP and its metabolites also can down-regulate fibronectin secretion in HK2 cells stimulated by TGFβ1 and inhibit smad2/3 phosphorylation.

CONCLUSION

HP has beneficial effect on DN by increasing Nrf2 expression and inhibiting TGF-smad signal activation. Further, it can be a novel herbal drug against DN.

Association of neutrophil-to-lymphocyte ratio with early renal dysfunction and albuminuria among diabetic patients

PURPOSE

Neutrophil-to-lymphocyte ratio (NLR) was widely studied as a prognostic marker in various medical and surgical specialties, but its significance in diabetic kidney disease is not yet established.

METHODS

The subjects comprised 199 men aged 73 ± 11 (mean ± standard deviation) years and 187 women aged 77 ± 10 years from a rural hospital. We examined the relationship between NLR calculated by analyzing differential leukocyte count in complete blood picture and renal function evaluated by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study Group equation and urinary albumin excretion (UAE).

RESULTS

NLR was negatively related to eGFR and positively related to UAE. Multiple linear regression analysis using eGFR and UAE as an objective variables, adjusted for confounding factors as explanatory variables showed that NLR (β = - 0.101, p = 0.009) as well as age, body mass index, serum uric acid, and presence of uric acid lowing medication were significantly and independently associated with eGFR, and NLR (β = 0.113, p = 0.031) as well as prevalence of cardiovascular disease, systolic blood pressure, presence of antihypertensive medication, presence of antilipidemic medication, and eGFR were significantly and independently associated with UAE. The multivariate-adjusted odds ratios (95% confidence interval) of NLR for stage 3a (eGFR < 60 mL/min/1.73 m²), stage 3b (eGFR < 45 mL/min/1.73 m²), and microalbuminuria (UAE ≥ 30 mg/g Cr) were 1.90 (1.02-3.56) and 2.99 (1.28-6.98), and 1.77 (1.04-3.01), respectively. Next, to examine the consistency of the observed association between NLR and eGFR, we performed subgroup analyses. There was a significant interaction (p = 0.006) only between the two groups regarding antihypertensive medication (absence: β = - 0.272, p < 0.001 and presence: β = - 0.029, p = 0.564).

CONCLUSIONS

Our data suggested that NLR might be important as a potential factor for evaluating patients with a higher degree of albuminuria among diabetic outpatients.

2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione isolated from Averrhoa carambola L. root ameliorates diabetic nephropathy by inhibiting the TLR4/MyD88/NF-κB pathway

BACKGROUND

Averrhoa carambola L. is a traditional medicinal herb that has long been used to treat diabetes. Our previous studies found that 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) isolated from A. carambola L. roots could ameliorate diabetic nephropathy (DN), but its exact mechanism remains unclear.

METHODS

A DN model was established by streptozotocin (STZ, 100 mg/kg body weight) in TLR4 knockout (TLR4-/-, KO) mice and wild-type (WT) mice. Body weight and blood glucose were evaluated after oral administration of DMDD (12.5, 25, 50 mg/kg body weight/d) in diabetic mice. The levels of serum lipids, including TC, TG, HDL, and LDL and kidney function indexes Scr and BUN, were detected by biochemical equipment. The levels of inflammatory cytokines including IL-6 and TNF-α, were determined by ELISA kits. Furthermore, changes in renal ultrastructure were observed by electron microscopy. Western blot analysis and RT-PCR were used to assess the protein expression and mRNA levels of TLR4, MyD88 and NF-κB.

RESULTS

DMDD treatment attenuated diabetic nephropathy, as a result of a decline in blood glucose, serum creatinine, and blood urine nitrogen levels and an increase in the quantity and density of podocytes, combined with improved dyslipidaemia. DMDD treatment inhibited the inflammatory response and downregulated the expression of the TLR4/MyD88/NF-κB pathway in diabetic mice, and these changes were significantly different in TLR4-/- mice.

CONCLUSION

DMDD alleviates diabetic nephropathy by mitigating kidney damage and inflammation via the inhibition of the TLR4/MyD88/NF-κB signalling pathway.

Dapagliflozin, a sodium-glucose co-transporter-2 inhibitor, slows the progression of renal complications through the suppression of renal inflammation, endoplasmic reticulum stress and apoptosis in prediabetic rats

AIM

To evaluate the renoprotective roles of dapagliflozin in prediabetic rats in order to elucidate the effects of this sodium-glucose co-transporter-2 (SGLT2) inhibitor on the renal complications associated with metabolic dysfunction in diet-induced obesity.

METHODS

Obesity was induced by feeding a high-fat diet (HFD) to male Wistar rats for 16 weeks. HFD-fed rats were treated with dapagliflozin (1 mg/kg/d) or metformin (30 mg/kg/d) by oral gavage for 4 weeks after insulin resistance had been established. The metabolic characteristics and renal function associated with lipid accumulation, inflammation, fibrosis, endoplasmic reticulum (ER) stress and apoptosis in the renal tissue were examined.

RESULTS

The results showed that HFD-fed rats developed both obesity and impaired renal function, along with increased renal triglyceride accumulation. Importantly, dapagliflozin had greater efficacy in improving renal function and reducing both body weight and visceral fat accumulation than metformin treatment. Dapagliflozin and metformin were found to have similar effects regarding the suppression of renal triglycerides, superoxide dismutase (SOD) expression and malondialdehyde (MDA) levels, subsequently leading to a decrease in renal inflammation and fibrosis. Renal ER stress and apoptosis were increased in HFD-fed rats and were effectively reduced after administration of dapagliflozin. The expression of renal SGLT2 was not affected by administration of dapagliflozin or metformin.

CONCLUSION

Collectively, these findings indicate that dapagliflozin exerts renoprotective effects by alleviating obesity-induced renal inflammation, fibrosis, ER stress, apoptosis and lipid accumulation in the prediabetic condition.

Decreased regulatory function of CD4+CD25+CD45RA+ T cells and impaired IL-2 signalling pathway in patients with type 2 diabetes mellitus

In this study, the frequency and function of CD4⁺CD25⁺CD45RA⁺ regulatory T cells (Treg) and intracellular IL-2 signalling molecules in patients with type 2 diabetes mellitus (T2DM) were investigated. Tregs and responder T cells (Tresp, CD4⁺CD25^- T cells) were sorted and suppression assays were performed using flow cytometry. Phosphorylation of signal transducer and activator of transcription-5 (pSTAT5) were assessed using flow cytometry. Gene expression of FOXP3 was performed with the SYBR green Real Time PCR method. Production of IL-2 from cultured cells was assessed using ELISA. We observed a functional defect of CD4⁺CD25⁺CD45RA⁺ Tregs in T2DM patients with higher proliferation of Tresp cells, in response to anti-CD3 and anti CD28 stimulation in the presence of Tregs in vitro. The results showed that the proliferation of Tresps in the absence of Treg cells was higher in T2DM patients than in healthy controls. Decreased FOXP3 mRNA expression and pSTAT5 were observed within the Tregs of the patients, whereas the level of secreted IL-2 from PBMCs culture was not statically different between T2DM patients and healthy individuals. Changes in intracellular IL-2 pathways and FOXP3 gene expression may contribute to the defect of Tregs in T2DM patients. These findings indicating that the purified CD4⁺CD25⁺CD45RA⁺ Treg cells have reduced functional capacity together with impaired IL-2 pathway in T2DM, and the Tregs could be used for a potential novel therapeutic target.

A study on correlation between oxidative stress parameters and inflammatory markers in type 2 diabetic patients with kidney dysfunction in north Indian population

BACKGROUND

Research reports support the statement that oxidative stress and inflammation are well-known risk factors for chronic kidney disease (CKD) in patients with diabetes. This study was designed to ascertain the associated role of oxidative stress parameters and inflammatory markers in diabetes and related CKD among the north Indian population.

METHODS

The study was divided into three groups as healthy subjects (group 1), patients with diabetes without complication (group 2), and with CKD (group 3). Serum levels of malondialdehyde (MDA) and nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) content were estimated in all individuals. Inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)-α were determined by enzyme-linked immuno-sorbent assay.

RESULTS

MDA, protein carbonyl, and NO were significantly elevated in patients with type 2 diabetes as compared with healthy subjects (P ≤ 0.05). Total thiols content were found to be significantly decreased in patients with diabetes with CKD. The activity of antioxidant enzymes SOD, CAT, and GR showed a significant suppression in patients with type 2 diabetes with or without CKD as compared with healthy subjects. Nevertheless, the levels of proinflammatory cytokines IL-6 and TNF-α were significantly upregulated ( P ≤ 0.05) as compared with healthy subjects.

CONCLUSION

Determination of antioxidant defense parameters and inflammatory markers contributes to understand the relationship between oxidative stress and inflammation on the development and prevention of chronic kidney disease in Indian patients with diabetes.

Inhibition of inflammation using diacerein markedly improved renal function in endotoxemic acute kidney injured mice

BACKGROUND

Inflammation is an important pathogenic component of endotoxemia-induced acute kidney injury (AKI), finally resulting in renal failure. Diacerein is an interleukin-1β (IL-1β) inhibitor used for osteoarthritis treatment by exerting anti-inflammatory effects. This study aims to investigate the effects of diacerein on endotoxemia-induced AKI.

METHODS

Male C57BL/6 mice were intraperitoneally injected with lipopolysaccharide (LPS, 10 mg/kg) for 24 h prior to diacerein treatment (15 mg/kg/day) for another 48 h. Mice were examined by histological, molecular and biochemical approaches.

RESULTS

LPS administration showed a time-dependent increase of IL-1β expression and secretion in kidney tissues. Diacerein treatment normalized urine volume and osmolarity, reduced blood urea nitrogen (BUN), fractional excretion of sodium (FENa), serum creatinine and osmolarity, and protected renal function in an endotoxemic AKI mice model. In the histopathologic study, diacerein also improved renal tubular damage such as necrosis of the tubular segment. Moreover, diacerein inhibited LPS-induced increase of inflammatory cytokines, such as IL-1β, tumor necrosis factor-α, monocyte chemoattractant protein-1 and nitric oxide synthase 2. In addition, LPS administration markedly decreased aquaporin 1 (AQP1), AQP2, AQP3, Na,K-ATPase α1, apical type 3 Na/H exchanger and Na-K-2Cl cotransporter expression in the kidney, which was reversed by diacerein treatment. We also found that diacerein or IL-1β inhibition prevented the secretion of inflammatory cytokines and the decrease of AQP and sodium transporter expression induced by LPS in HK-2 cells.

CONCLUSION

Our study demonstrates for the first time that diacerein improves renal function efficiently in endotoxemic AKI mice by suppressing inflammation and altering tubular water and sodium handing. These results suggest that diacerein may be a novel therapeutic agent for the treatment of endotoxemic AKI.

The association of neutrophil to lymphocyte ratio, mean platelet volume, and platelet distribution width with diabetic retinopathy and nephropathy: a meta-analysis

The aim of the present study was to investigate the correlation of neutrophil to lymphocyte ratio (NLR), mean platelet volume (MPV), and platelet distribution width (PDW) with diabetic nephropathy (DN) and diabetic retinopathy (DR). We searched for eligible studies from PubMed, Embase, Web of Science, and CNKI up to 1 December 2017. Standardized mean difference (SMD) was calculated with a confidence interval (CI) of 95%. A total of 48 studies were included in our meta-analysis. Compared with patients with type Ⅱ diabetes mellitus (T2DM) and without DR, NLR, MPV, and PDW were higher in patients with DR (SMD = 0.77; 95% CI: 0.49-1.05; P<0.001; SMD = 0.68; 95% CI: 0.36-0.99; P<0.001; SMD = 0.52; 95% CI: 0.28-0.76; P<0.01). Compared with patients with T2DM and without DN, NLR, MPV, and PDW were higher in patients with DN (SMD = 0.63; 95% CI: 0.43-0.83; P<0.001; SMD = 0.81; 95% CI: 0.36-1.25; P<0.001; SMD = 0.70; 95% CI: 0.50-0.90; P<0.001). We also found that MPV was strongly associated with the severity of DR, and NLR was closely related to the degree of DN. Our findings indicated that NLR, MPV, and PDW could be recommended as inexpensive diagnostic biomarkers for DN and DR. However, considering several limitations in the present study, further high-quality clinical studies should be performed to investigate the relationship of NLR, MPV, and PDW to DN and DR.

Intercellular adhesion molecule-1 in diabetic patients with and without microalbuminuria

BACKGROUND

Nephropathy is a major complication of type 2 diabetes mellitus (T2DM) and is heralded by the insidious development of microalbuminuria (MA). It is suggested that the serum levels of Intercellular Adhesion Molecule-1 (ICAM-1) is correlated with diabetic nephropathy. In this cross-sectional study, we evaluated serum ICAM-1 level in diabetic patients with and without MA.

METHODS

A total of 187 participants were enrolled and were classified into three groups including 40 healthy controls and 2 diabetic groups with (n = 59) or without MA (n = 88). Serum levels of ICAM-1, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol and C-reactive protein (CRP) were measured in all three groups. Statistical analyses were performed using the SPSS software. A P-value less than 0.05 was considered statistically significant.

RESULTS

Serum levels of ICAM-1 were significantly higher in diabetic patients irrespective of MA. Moreover, ICAM-1 levels in patients with MA were significantly higher than patients without MA. Patients with MA had significantly higher age and blood pressure compared to those without MA (P = 0.001). Serum levels of ICAM-1 were significantly correlated with age and HbA1c.

CONCLUSIONS

Overall, serum ICAM-1 levels were significantly higher in T2DM patients with MA and it may be associated with the severity of diabetic kidney disease.

Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy

Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.

The introduction of simple cardiorespiratory fitness testing in overweight/obese type 2 diabetics: a pilot study

BACKGROUND

Low level of cardiorespiratory fitness has been recognized as an important independent and modifiable risk factor of increased morbidity and mortality. However, in standard outpatient settings, patients are not routinely screened for fitness and advantages of such testing for the management of type 2 diabetes have not been defined.AimTo describe the toleration of a fast, simple and practicable fitness test (2-min step-in-place test) by overweight/obese type 2 diabetics and their performance indicated by 2-min step-in-place test score (STS). To study short-term anthropometric, functional and metabolic changes following the implementation of the test in the selected population.

METHODS

A total of 33 overweight/obese type 2 diabetics underwent, besides routine examination at the outpatient clinic, the fitness test (group A). Patients were asked to increase their regular physical activity with focus on walking without change in diet and chronic medication. Three to four months later, the subjects were tested again. An identical number of age- and sex-matched obese diabetics followed in our outpatient clinic (without fitness testing), was randomly selected from the Hospital Information System (control group B).FindingsAll patients subjected to fitness testing completed the protocol successfully. STS score was found to have a considerable range with differences between males and females at the borderline of statistical significance. The data are compliant with lower aerobic endurance of obese diabetics compared with healthy population. Within study period, the tested group presented with improvements in STS (referring especially to the males) as well as in several laboratory parameters of glucose and lipid homeostasis, glomerular function and subclinical inflammation with no reflection in anthropometry. Group B demonstrated no significant change. In conclusion, 2-min step-in-place test is fast, undemanding and well-tolerated by patients and personnel. Following its validation based on cardiopulmonary exercise testing, the test may prove recommendable for screening or self-monitoring purposes.

Susceptible and Prognostic Genetic Factors Associated with Diabetic Peripheral Neuropathy: A Comprehensive Literature Review

Type 2 diabetes mellitus (T2D) is a disorder of glucose metabolism. It is a complex process involving the regulation of insulin secretion, insulin sensitivity, gluconeogenesis, and glucose uptake at the cellular level. Diabetic peripheral neuropathy (DPN) is one of the debilitating complications that is present in approximately 50% of diabetic patients. It is the primary cause of diabetes-related hospital admissions and nontraumatic foot amputations. The pathogenesis of diabetic neuropathy is a complex process that involves hyperglycemia-induced oxidative stress and altered polyol metabolism that changes the nerve microvasculature, altered growth factor support, and deregulated lipid metabolism. Recent literature has reported that there are several heterogeneous groups of susceptible genetic loci which clearly contribute to the development of DPN. Several studies have reported that some patients with prediabetes develop neuropathic complications, whereas others demonstrated little evidence of neuropathy even after long-standing diabetes. There is emerging evidence that genetic factors may contribute to the development of DPN. This paper aims to provide an up-to-date review of the susceptible and prognostic genetic factors associated with DPN. An extensive survey of the scientific literature published in PubMed using the search terms "Diabetic peripheral neuropathy/genetics" and "genome-wide association study" was carried out, and the most recent and relevant literature were included in this review.

Protein tyrosine phosphatase 1B deficiency in podocytes mitigates hyperglycemia-induced renal injury

OBJECTIVE

Diabetic nephropathy is one of the most devastating complications of diabetes, and growing evidence implicates podocyte dysfunction in disease pathogenesis. The objective of this study was to investigate the contribution of protein tyrosine phosphatase 1B (PTP1B) in podocytes to hyperglycemia-induced renal injury.

METHODS

To determine the in vivo function of PTP1B in podocytes we generated mice with podocyte-specific PTP1B disruption (hereafter termed pod-PTP1B KO). Kidney functions were determined in control and pod-PTP1B KO mice under normoglycemia and high-fat diet (HFD)- and streptozotocin (STZ)-induced hyperglycemia.

RESULTS

PTP1B expression increased in murine kidneys following HFD and STZ challenges. Under normoglycemia control and pod-PTP1B KO mice exhibited comparable renal functions. However, podocyte PTP1B disruption attenuated hyperglycemia-induced albuminuria and renal injury and preserved glucose control. Also, podocyte PTP1B disruption was accompanied with improved renal insulin signaling and enhanced autophagy with decreased inflammation and fibrosis. Moreover, the beneficial effects of podocyte PTP1B disruption in vivo were recapitulated in E11 murine podocytes with lentiviral-mediated PTP1B knockdown. Reconstitution of PTP1B in knockdown podocytes reversed the enhanced insulin signaling and autophagy suggesting that they were likely a consequence of PTP1B deficiency. Further, pharmacological attenuation of autophagy in PTP1B knockdown podocytes mitigated the protective effects of PTP1B deficiency.

CONCLUSIONS

These findings demonstrate that podocyte PTP1B deficiency attenuates hyperglycemia-induced renal damage and suggest that PTP1B may present a therapeutic target in renal injury.

Neutrophil-lymphocyte Ratio is a Novel Reliable Predictor of Nephropathy, Retinopathy, and Coronary Artery Disease in Indians with Type-2 Diabetes

BACKGROUND AND AIMS

Neutrophil-lymphocyte ratio (NLR) has been suggested to be a predictor of coronary artery disease (CAD), and end-organ damage in type-2 diabetes mellitus (T2DM). Similar data are lacking from Indians with T2DM. Hence, this study aimed to evaluate the role of NLR as a predictor of microvascular complications and CAD in T2DM.

SUBJECTS AND METHODS

Consecutive T2DM patients attending the outpatient services of 2 different hospitals, who gave consent, underwent clinical, anthropometric evaluation, and evaluation for the occurrence of retinopathy, nephropathy, neuropathy, and CAD.

RESULTS

A total of 298 patients were screened of which 265 patients' data were analyzed. Occurrence of hypertension, neuropathy, nephropathy, retinopathy, and CAD was 12.8%, 18.5%, 41.5%, 62.3%, and 3.8%, respectively. Patients in higher NLR quartiles had significantly higher diabetes duration, occurrence of nephropathy, albuminuria, retinopathy, CAD and lpwer glomerular filtration rate. Patients with more microvascular complications had significantly longer diabetes duration, blood pressure, NLR, creatinine, and urine albumin excretion. Binary logistic regression revealed NLR followed by body mass index were best predictors of microvascular complications. NLR had areas under the receiver operating characteristic curve (AUC) of 0.888 (95% CI: 0.848-0.929; P < 0.001), 0.708 (95% CI: 0.646-0.771; P < 0.001), and 0.768 (95% CI: 0.599-938; P = 0.004) in predicting albuminuria, retinopathy, and CAD, respectively. NLR of 2.00 had sensitivity and specificity of 86.4% and 69% in predicting albuminuria; sensitivity and specificity of 64.2% and 63% in predicting retinopathy; sensitivity and specificity of 80% and 47.1% in predicting CAD.

CONCLUSION

NLR is inexpensive, easy to use, reliable predictor of nephropathy, retinopathy, and CAD in Indian T2DM.

Effect of diacerein on renal function and inflammatory cytokines in participants with type 2 diabetes mellitus and chronic kidney disease: A randomized controlled trial

Diacerein seems to improve metabolic control and reduce inflammatory marker levels in individuals with type 2 diabetes mellitus (Type 2 DM), but for participants with chronic kidney disease (CKD) its effect is unknown. This study aimed to evaluate the effect of diacerein vs. placebo on urinary albumin/creatinine ratio (ACR), glomerular filtration rate (GFR), and inflammatory cytokines in type 2 DM participants with CKD. Blood pressure (BP) and metabolic control were secondary outcomes. This randomized, placebo-controlled, parallel trial of adjuvant treatment of type 2 DM with diacerein enrolled seventy-two participants with CKD, aged 30–80 years, with glycated hemoglobin levels from 53–97 mmol/mol (7.0–11.0%), receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and antidiabetic agents. Participants randomized to diacerein or placebo were followed-up up to 90 days. Both groups had a marked reduction in ACR, but there was no effect on glomerular filtration rate. While the diacerein group had reduced TNF-α levels at the 75th percentile with a borderline significance (P = 0.05), there were no changes in the IL levels at the 75^th percentile.

Diacerein prevented the increase in blood glucose to the level observed in the placebo group (P = 0.04), improving metabolic control by 74%, reducing 24-hour diastolic BP, nighttime systolic and diastolic BP compared to the placebo group. In conclusion, among patients with type 2 DM and CKD, diacerein does not have an effect on ACR or GFR, but slows metabolic control deterioration and is associated with lower nighttime systolic and diastolic blood pressure.

Trial registration: Brazilian Clinical Trials Registry (Registro Brasileiro de Ensaios Clinicos; ReBeC) U1111-1156-0255