Trans-resveratrol mitigates type 1 diabetes-induced oxidative DNA damage and accumulation of advanced glycation end products in glomeruli and tubules of rat kidneys

Identification of Lipotoxicity-Related Biomarkers in Diabetic Nephropathy Based on Bioinformatic Analysis

Objective: This study is aimed at investigating diagnostic biomarkers associated with lipotoxicity and the molecular mechanisms underlying diabetic nephropathy (DN). Methods: The GSE96804 dataset from the Gene Expression Omnibus (GEO) database was utilized to identify differentially expressed genes (DEGs) in DN patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted using the DEGs. A protein-protein interaction (PPI) network was established to identify key genes linked to lipotoxicity in DN. Immune infiltration analysis was employed to identify immune cells with differential expression in DN and to assess the correlation between these immune cells and lipotoxicity-related hub genes. The findings were validated using the external dataset GSE104954. ROC analysis was performed to assess the diagnostic performance of the hub genes. The Gene set enrichment analysis (GSEA) enrichment method was utilized to analyze the key genes associated with lipotoxicity as mentioned above. Result: In this study, a total of 544 DEGs were identified. Among them, extracellular matrix (ECM), fatty acid metabolism, AGE-RAGE, and PI3K-Akt signaling pathways were significantly enriched. Combining the PPI network and lipotoxicity-related genes (LRGS), LUM and ALB were identified as lipotoxicity-related diagnostic biomarkers for DN. ROC analysis showed that the AUC values for LUM and ALB were 0.882 and 0.885, respectively. The AUC values for LUM and ALB validated in external datasets were 0.98 and 0.82, respectively. Immune infiltration analysis revealed significant changes in various immune cells during disease progression. Macrophages M2, mast cells activated, and neutrophils were significantly associated with all lipotoxicity-related hub genes. These key genes were enriched in fatty acid metabolism and extracellular matrix-related pathways. Conclusion: The identified lipotoxicity-related hub genes provide a deeper understanding of the development mechanisms of DN, potentially offering new theoretical foundations for the development of diagnostic biomarkers and therapeutic targets related to lipotoxicity in DN.

Lycopene prevents cell death in NRK-52E cells by inhibition of high glucose-activated DNA damage and apoptotic, autophagic, and necrotic pathways

This study aims to investigate the effects of lycopene on apoptotic, autophagic, and necrotic pathways, oxidative status, and DNA damage in diabetic nephropathy at the molecular level. The sample of the study includes seven groups: lycopene (L), high glucose (G), high glucose + lycopene (GL), and control (C) groups tested at 12 and 24 h. The expression levels of genes in oxidative, apoptotic, autophagic, and necrotic cell death pathways are determined by reverse transcription-quantitative polymerase chain reaction analysis. The comet assay method is used for the analysis of DNA damage. It is observed that adding lycopene to high glucose for protective purposes reduces the expression of genes related to apoptosis, autophagy, and necrosis, as well as the DNA damage index, compared to cells given high glucose alone. Lycopene can be a safe and effective alternative agent.

The Mechanism of Mori Folium and Eucommiae Cortex against Cyclophosphamide-Induced Immunosuppression Integrating Network Pharmacology, Molecular Docking, Molecular Dynamics Simulations, and Experimental Validation

It has been reported that Mori Folium (MF) and Eucommiae Cortex (EC) exhibit pharmacological effects in the treatment of immunosuppression. However, the mechanism of MF and EC against immunosuppression remains unclear. This study aims to explore the mechanism of action of MF and EC for the treatment of immunosuppression through network pharmacology, molecular docking, molecular dynamics simulations and animal experiments. As a result, 11 critical components, 9 hub targets, and related signaling pathways in the treatment of immunosuppression were obtained based on network pharmacology. The molecular docking suggested that 11 critical components exhibited great binding affinity to 9 hub targets of immunosuppression. The molecular dynamics simulations results showed that (-)-tabernemontanine-AR, beta-sitosterol-AR and Dehydrodieugenol-HSP90AA1 complexes are stably bound. Additionally, in the animal experiments, the treated group results compared to the control group suggest that MF and EC have a significant effect on the treatment of immunosuppression. Therefore, MF and EC treatment for immunosuppression may take effects in a multi-component, multi-target, and multi-pathway manner. The results herein may provide novel insights into the treatment of immunosuppression in humans.

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.

A Review of Medicinal Plants with Renoprotective Activity in Diabetic Nephropathy Animal Models

Diabetic nephropathy (DN), also recognized as diabetic kidney disease, is a kidney malfunction caused by diabetes mellitus. A possible contributing factor to the onset of DN is hyperglycemia. Poorly regulated hyperglycemia can damage blood vessel clusters in the kidneys, leading to kidney damage. Its treatment is difficult and expensive because its causes are extremely complex and poorly understood. Extracts from medicinal plants can be an alternative treatment for DN. The bioactive content in medicinal plants inhibits the progression of DN. This work explores the renoprotective activity and possible mechanisms of various medicinal plant extracts administered to diabetic animal models. Research articles published from 2011 to 2022 were gathered from several databases including PubMed, Scopus, ProQuest, and ScienceDirect to ensure up-to-date findings. Results showed that medicinal plant extracts ameliorated the progression of DN via the reduction in oxidative stress and suppression of inflammation, advanced glycation end-product formation, cell apoptosis, and tissue injury-related protein expression.

Can grape polyphenols affect glycation markers? A systematic review

Advanced glycation end-products (AGEs) favor inflammation and oxidative stress, playing a role in chronic diseases pathogenesis. Grape polyphenols exert antiglycative and antioxidant effects which may contribute to prevent chronic diseases. However, clinical evidence of grape polyphenols on chronic disease prevention and treatment by glycation markers modulation are limited. Therefore, we aimed to critically analyze studies about that topic to investigate the antiglycative power of dietary grape polyphenol, and to explore the molecular mechanism involved. This systematic review was conducted and reported according to PRISMA guidelines. The following search terms were used: "grape", "extract", "grape seed extract", "grape skin extract", "polyphenol extract", "grape polyphenol(s)", "grape juice", "resveratrol", "quercetin", "catechin", "epicatechin", "procyanidin(s)", and "anthocyanin(s)". Seven studies were included. Glycated hemoglobin was not affected. The interventions duration may not have been enough to detect changes. Grape polyphenols reduced fructosamine and methylglyoxal (MGO) concentrations, and increased endogenous secretory RAGE (esRAGE) gene expression but did not affect the serum concentration. Resveratrol antiglycative effects are mainly due its ability to trap MGO and downregulate RAGE. In conclusion, grape polyphenols may have a positive impact on early glycation products, AGEs and esRAGE. Future studies are needed to explore how they modulate AGEs and receptors in chronic diseases.

Phytochemicals as Potential Inhibitors of Advanced Glycation End Products: Health Aspects and Patent Survey

BACKGROUND

The glycation of proteins and lipids synthesizes the advanced glycation end products (AGEs), i.e., substances that irreversibly damage macromolecules present in tissues and organs, which contribute to the impairment of biological functions. For instance, the accumulation of AGEs induces oxidative stress, the inflammatory responses, and consequently the on set/worsening of diseases, including obesity, asthma, cognitive impairment, and cancer. There is a current demand on natural and low-cost sources of anti-AGE agents. As a result, food phytochemicals presented promising results to inhibit glycation and consequently, the formation of AGEs.

OBJECTIVE

Here we describe how the AGEs are present in food via Maillard reaction and in organs via natural aging, as well as the effects of AGEs on the worsening of diseases. Also we described the methods used to detect AGEs in samples, and the current findings on the use of phytochemicals (phenolic compounds, phytosterols, carotenoids, terpenes and vitamins) as natural therapeuticals to inhibit health damages via inhibition of AGEs in vitro and in vivo.

METHODS

This manuscript reviewed publications available in the PubMed and Science Direct databases dated from the last 20 years on the uses of phytochemicals for the inhibition of AGEs. Recent patents on the use of anti-AGEs drugs were reviewed with the use of Google Advanced Patents database.

RESULTS AND DISCUSSION

There is no consensus about which concentration of AGEs in blood serum should not be hazardous to the health of individuals. Food phytochemicals derived from agroindustry wastes, including peanut skins, and the bagasses derived from citrus and grapes are promising anti-AGEs agents via scavenging of free radicals, metal ions, the suppression of metabolic pathways that induces inflammation, the activation of pathways that promote antioxidant defense, and the blocking of AGE connection with the receptor for advanced glycation endproducts (RAGE).

CONCLUSION

Phytochemicals derived from agroindustry are promising anti-AGEs, which can be included to replace synthetic drugs to inhibit AGE formation, and consequently to act as therapeutical strategy to prevent and treat diseases caused by AGEs, including diabetes, ovarian cancer, osteoporosis, and Alzheimer's disease.

Antioxidant and Anti-inflammatory Properties of Resveratrol in Diabetic Nephropathy: A Systematic Review and Meta-analysis of Animal Studies

Background: Accumulated experimental evidence suggests that resveratrol may have an effect on diabetic nephropathy by inhibiting inflammation and decreasing oxidative stress. However, the credibility of the evidence for this practice is unclear. Thus, we aimed to perform a systematic review and meta-analysis of animal studies to evaluate the antioxidant and anti-inflammatory properties of resveratrol when used in the treatment of diabetic nephropathy.

Methods: Electronic bibliographic databases including PubMed, EMBASE, and Web of Science were searched for relevant studies. The methodological quality of animal studies was assessed based on the SYstematic Review Center for Laboratory animal Experimentation Risk of Bias (SYRCLE’s RoB) tool. A meta-analysis was performed based on the Cochrane Handbook for Systematic Reviews of Interventions by using RevMan 5.4 software. This study was registered within International Prospective Register of Systematic Reviews (PROSPERO) as number CRD42021293784.

Results: Thirty-six qualified studies involving 726 animals were included. There was a significant association of resveratrol with the levels of blood glucose (BG), serum creatinine (Scr), blood urea nitrogen (BUN), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GPx), and interleukin-1β (IL-1β). Nevertheless, resveratrol treatment did not effectively decrease the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In addition, more remarkable antioxidant and hypoglycemic effects were observed in type 2 diabetic nephropathy rather than in type 1 diabetic nephropathy based on subgroup analysis.

Conclusion: In this meta-analysis, resveratrol can exert its antioxidant activities by reducing the levels of MDA and recovering the activities of SOD, CAT, GSH, and GPx. With regard to pro-inflammatory cytokines, resveratrol had a positive effect on the reduction of IL-1β. However, the analysis indicated that resveratrol had no effect on IL-6 and TNF-α levels, probably because of the methodological quality of the studies and their heterogeneity. Current evidence supports the antioxidant and anti-inflammatory properties of resveratrol, but its relationship with the levels of some inflammatory cytokines such as IL-6 and TNF-α in animals with diabetic nephropathy needs further elucidation.

The effect of resveratrol on advanced glycation end products in diabetes mellitus: a systematic review

Advanced glycation end products (AGEs) lead to chronic oxidative stress and inflammation, which in turn augment diabetes complications. Resveratrol plays a potential role in relation to diabetes due to improving of hyperglycemia, oxidative stress, and inflammation. The aim of this review was to evaluate the scientific literature to identify the impacts of resveratrol on the accumulation of AGEs. The literature was searched in the online databases, viz. PubMed, SCOPUS, Embase, ProQuest, and Google Scholar until May 2019. From a total of 338 retrieved articles, 10 papers were eligible for the present analysis. Except one clinical trial, all studies were conducted on animals. All the included studies, except one, showed inhibitory effects of resveratrol on the accumulation of AGE or receptor for AGEs. The findings indicate that resveratrol is a potential protective agent against the accumulation of AGEs. There is, however, the need for future studies to investigate this effect on human.

Role of Polyphenol in Regulating Oxidative Stress, Inflammation, Fibrosis, and Apoptosis in Diabetic Nephropathy

Diabetic nephropathy (DN) is known as one of the driving sources of end-stage renal disease (ESRD). DN prevalence continues to increase in every corner of the world andthat has been a major concern to healthcare professionals as DN is the key driver of diabetes mellitus (DM) morbidity and mortality. Hyperglycaemia is closely connected with the production of reactive oxygen species (ROS) that cause oxidative stress response as well as numerous cellular and molecular modifications. Oxidative stress is a significant causative factor to renal damage, as it can activate other immunological pathways, such as inflammatory, fibrosis, and apoptosis pathways. These pathways can lead to cellular impairment and death as well as cellular senescence. Natural substances containing bioactive compounds, such as polyphenols, have been reported to exert valuable effects on various pathological conditions, including DM. The role of polyphenols in alleviating DN conditions has been documented in many studies. In this review, the potential of polyphenols in ameliorating the progression of DN via modulation of oxidative stress, inflammation, fibrosis, and apoptosis, as well as cellular senescence, has been addressed. This information may be used as the strategies for the management of DN and development as nutraceutical products to overcome DN development.

Genotoxic effects and molecular docking of 1,4-dioxane: combined protective effects of trans-resveratrol

In this study, the protective effects of trans-resveratrol (t-resv) against 1,4-dioxane-induced toxicity in meristematic cells were investigated. For this purpose, Allium test was used and the alterations in all experimental groups were examined by using physiological, cytogenetic, biochemical, and anatomical parameters. In order to elucidate the toxicity mechanism, interactions of 1,4-dioxane and intracellular antioxidant molecules were investigated by molecular docking. As a result of the analysis, it was determined that 1,4-dioxane causes serious abnormalities in Allium cepa meristematic cells. In 1,4-dioxane-treated group, germination percentage was regressed 1.6 times, root length was reduced 12.7 times, and weight gain was decreased 7.7 times compared to control group. T-resv administration with 1,4-dioxane resulted in an improvement in physiological parameters and reduced the relative injury rate from 0.4 to 0.16. Mitotic index (MI), micronucleus (MN), and chromosomal abnormality (CAs) frequencies were investigated as cytogenetic parameters. 1,4-Dioxane decreased MI index, and increased CAs and MN frequency. In addition, it was determined by the comet test that 1,4-dioxane caused deterioration in DNA integrity. T-resv treatment was found to cause a dose-dependent improvement in genotoxic effects. Changes in the antioxidant system in all experimental groups were determined by measuring malondialdehyde (MDA) and glutathione (GSH) levels, superoxide dismutase (SOD), and catalase (CAT) enzyme activities. 1,4-Dioxane caused alterations in all tested parameters, causing deterioration in the oxidant/antioxidant balance in the cell. A 200-mg/L t-resv+1,4-dioxane treatment caused a 1.9-fold decrease in MDA level which is indicator of lipid peroxidation compared to only 1,4-dioxane-treated group. The mechanism of the disruption in antioxidant/oxidant dynamics and genetic integrity was elucidated by molecular docking analysis of 1,4-dioxane with antioxidant molecules and DNA. In 1,4-dioxane treatment group, anatomical changes such as cell deformation, flattened cell nucleus, and thickening of cortex cell wall were observed. The frequency of these changes decreased with t-resv administration. As a result, it was determined that 1,4-dioxane caused a versatile toxicity in A. cepa meristematic cells, while t-resv was found to have a dose-dependent protective feature against 1,4-dioxane-induced toxicity.

Effects of trans-resveratrol on type 1 diabetes-induced up-regulation of apoptosis and mitogen-activated protein kinase signaling in retinal pigment epithelium of Dark Agouti rats

Microvascular changes and retinal degeneration precede diabetic retinopathy. Oxidative stress alters several intracellular signaling pathways, which form the basis of diabetic retinopathy. Many antioxidants have been investigated as possible preventive and therapeutic remedies for diabetic retinopathy. The current study investigated the modulatory effects of trans-resveratrol on streptozotocin-induced type 1 diabetes mediated changes in the transcription and levels of apoptosis-related proteins and mitogen-activated protein kinases (MAPKs) in the retinal pigment epithelium (RPE) of adult male dark Agouti rats. In control rats, 5 mg/kg/d trans-resveratrol administration for 30 days increased gene expressions of tumor suppressor protein 53, Bcl2-associated X protein, B-cell lymphoma-2 (Bcl2), Caspase-3 (CASP3), CASP8 and CASP9, p38αMAPK, c-Jun N-terminal kinase-1 (JNK1), and extracellular signal-regulated kinase-1 (ERK1). On the other hand, diabetes decreased gene expressions of CASP3, CASP8, p38αMAPK, JNK, and ERK1. Trans-resveratrol reversed the inhibited gene expressions of CASP8, p38αMAPK, JNK, and ERK1 to normal control levels in diabetic rats. Trans-resveratrol normalized diabetes-induced upregulation of CASP3 and -9, cytochrome-c, Bcl-2, and ERK1 proteins. In conclusion, Trans-resveratrol-induced alterations in gene expressions do not seem to affect RPE functions as they do not reflect as altered protein functions. Trans-resveratrol imparts its protective effects by normalizing apoptosis-related proteins and ERK1 but does not affect JNK proteins. Trans-resveratrol causes cytostasis in RPE of normal rats by upregulating Bcl2 protein and apoptotic proteins.

AGE/RAGE in diabetic kidney disease and ageing kidney

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease that inevitably progress to end-stage kidney disease. Intervention strategies such as blood glucose control is effective for preventing DKD, but many patients with DKD still reach end-stage kidney disease. Although comprehensive mechanisms shed light on the progression of DKD, the most compelling evidence has highlighted that hyperglycemia-related advanced glycation end products (AGEs) formation plays a central role in the pathogenesis of DKD. Pathologically, accumulation of AGEs-mediated receptor for AGEs (RAGE) triggers oxidative stress and inflammation, which is the major deleterious effect of AGEs in host and intestinal microenvironment of diabetic and ageing conditions. The activation of AGEs-mediated RAGE could evoke nicotinamide adenine dinucleotide phosphate oxidase-induced reactive oxygen and nitrogen species production and subsequently give rise to oxidative stress in DKD and ageing kidney. Therefore, targeting RAGE with its ligands mediated oxidative stress and chronic inflammation is considered as an additional intervention strategy for DKD and ageing kidney. In this review, we summarize AGEs/RAGE-mediated oxidative stress and inflammation signaling pathways in DKD and ageing kidney, discussing opportunities and challenges of targeting at AGEs/RAGE-induced oxidative stress that could hold the promising potential approach for improving DKD and ageing kidney.

Malaysian Propolis and Metformin Synergistically Mitigate Kidney Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Rats

Diabetic nephropathy is reported to occur as a result of the interactions between several pathophysiological disturbances, as well as renal oxidative stress and inflammation. We examined the effect of Malaysian propolis (MP), which has anti-hyperglycemic, antioxidant and anti-inflammatory properties, on diabetes-induced nephropathy. Diabetic rats were either treated with distilled water (diabetic control (DC) group), MP (300 mg/kg b.w./day), metformin (300 mg/kg b.w./day) or MP + metformin for four weeks. We found significant increases in serum creatinine, urea and uric acid levels, decreases in serum sodium and chloride levels, and increase in kidney lactate dehydrogenase activity in DC group. Furthermore, malondialdehyde level increased significantly, while kidney antioxidant enzymes activities, glutathione level and total antioxidant capacity decreased significantly in DC group. Similarly, kidney immunoexpression of nuclear factor kappa B, tumor necrosis factor-α, interleukin (IL)-1β and caspase-3 increased significantly, while IL-10 immunoexpression decreased significantly in DC group relative to normal control group. Histopathological observations for DC group corroborated the biochemical data. Intervention with MP, metformin or both significantly mitigated these effects and improved renal function, with the best outcome following the combined therapy. MP attenuates diabetic nephropathy and exhibits combined beneficial effect with metformin.

FOXO3a Protects against Kidney Injury in Type II Diabetic Nephropathy by Promoting Sirt6 Expression and Inhibiting Smad3 Acetylation

Diabetic nephropathy (DN) is the most common cause of end-stage renal disease. Although numerous reports have demonstrated a correlation between epithelial-mesenchymal transition (EMT) and renal fibrosis, how these processes lead to tubular dysfunction remains unclear. Here, we show that FOXO3a protects kidneys from injury in type II DN by increasing Sirt6 expression, which deacetylates Smad3 and inhibits its transcriptional activity. The results showed that progressive EMT in the kidneys from db/db mice is associated with Sirt6 downregulation and involved in tubular injury and dysfunction. The reduction of Sirt6 levels in db/db mice resulted in progressive kidney injury, indicating the protective role of Sirt6. Furthermore, Sirt6 was shown to directly bind to Smad3, a key downstream mediator of TGF-β, and could deacetylate it to inhibit its nuclear accumulation and transcriptional activity in HK2 cells. Besides, we demonstrate that FOXO3a activates Sirt6 expression by binding to its promoter. shRNA-induced FOXO3a knockdown in the kidneys of db/db mice exacerbated tubular injury and renal function loss. Mechanistically, FOXO3a protects against kidney injury in type II DN through the Sirt6/Smad3 axis. Thus, the pharmacological targeting of FOXO3a-mediated Sirt6/Smad3 signaling pathways may provide a novel strategy for treating type II DN.

Exposure to High-Fat Style Diet Induced Renal and Liver Structural Changes, Lipid Accumulation and Inflammation in Intact and Ovariectomized Female Rats

Purpose

We hypothesized that low estrogen levels aggravate obesity-related complications. Diet-induced obesity can cause distinct pathologies, including impaired glucose tolerance, inflammation, and organ injury that leads to fatty liver and chronic kidney diseases. To test this hypothesis, ovariectomized (OVX) rats were fed a high-fat style diet (HFSD), and we examined structural changes and inflammatory response in the kidney and liver.

Methods

Sprague-Dawley female rats were ovariectomized or sham-operated and divided into four groups: sham-operated rats fed a normal diet (ND); ovariectomized rats fed a normal diet (OVX-ND); sham-operated rats fed a HFSD; ovariectomized rats fed a high-fat style diet (OVX-HFSD). Mean blood pressure and fasting blood glucose were measured on weeks 0 and 10. The rats were sacrificed 10 weeks after initiation of ND or HFSD, the kidney and liver were harvested for histological, immunohistochemical and immunofluorescence studies.

Results

HFSD-fed rats presented a significantly greater adiposity index compared to their ND counterparts. Liver index, fasting blood glucose and mean blood pressure was increased in OVX-HFSD rats compared to HFSD rats at study terminal. Histological and morphometric studies showed focal interstitial mononuclear cell infiltration in the kidney of HFSD rats with mesangial expansion being greater in the OVX-HFSD rats. Both HFSD fed groups showed increased expressions of renal inflammatory markers, namely TNF-alpha, IL-6 and MCP-1, and infiltrating M1 macrophages with some influence of ovarian hormonal status. HFSD-feeding also caused hepatocellular steatosis which was aggravated in ovariectomized rats fed the same diet. Furthermore, hepatocellular ballooning was observed only in the OVX-HFSD rats. Similarly, HFSD-fed rats showed increased expressions of the inflammatory markers and M1 macrophage infiltration in the liver; however, only IL-6 expression was magnified in the OVX-HFSD.

Conclusion

Our data suggest that some of the structural changes and inflammatory response in the kidney and liver of rats fed a HFSD are exacerbated by ovariectomy.

An updated pharmacological insight of resveratrol in the treatment of diabetic nephropathy

As one of the most common complications of diabetes, nephropathy develops in approximately 40% of diabetic individuals. Although end stage kidney disease is known as one of the most consequences of diabetic nephropathy, the majority of diabetic individuals might die from cardiovascular diseases and infections before renal replacement treatment. Moreover, the routine medical treatments for diabetes hold undesirable side effects. The explosive prevalence of diabetes urges clinicians and scientists to investigate the complementary or alternative therapies. Phytochemicals are emerging as alternatives with a wide range of therapeutic effects on various pathologies, including diabetic kidney disease. Of those phytochemicals, resveratrol, a natural polyphenolic stilbene, has been found to exert a broad spectrum of health benefits via various signaling molecules. In particular, resveratrol has gained a great deal of attention because of its anti-oxidative, anti-inflammatory, anti-diabetic, anti-obesity, cardiovascular-protective, and anti-tumor properties. In the renal system, emerging evidence shows that resveratrol has already been used to ameliorate chronic or acute kidney injury. This review critically summarizes the current findings and molecular mechanisms of resveratrol in diabetic renal damage. In addition, we will discuss the adverse and inconsistent effects of resveratrol in diabetic nephropathy. Although there is increasing evidence that resveratrol affords great potential in diabetic nephropathy therapy, these results should be treated with caution before its clinical translation. In addition, the unfavorable pharmacokinetics and/or pharmacodynamics profiles, such as poor bioavailability, may limit its extensive clinical applications. It is clear that further research is needed to unravel these limitations and improve its efficacy against diabetic nephropathy. Increasing investigation of resveratrol in diabetic kidney disease will not only help us better understand its pharmacological actions, but also provide novel potential targets for therapeutic intervention.

Advanced Glycation End Products (AGE) and Soluble Forms of AGE Receptor: Emerging Role as Mortality Risk Factors in CKD

Advanced glycation end-products (AGE) can promote chronic kidney disease (CKD) progression and CKD-related morbidities. The soluble receptor for AGE (sRAGE) is a potential biomarker of inflammation and oxidative stress. Here, we explored the role of AGE, glycated albumin, sRAGE and its different forms, cRAGE and esRAGE, as prognostic factors for mortality in 111 advanced CKD patients. The median follow-up time was 39 months. AGE were quantified by fluorescence, sRAGE and its forms by ELISA. Malnutrition was screened by the Malnutrition Inflammation Score (MIS). The Cox proportional hazards regression model was used to assess the association of variables with all-cause mortality. Mean levels of sRAGE, esRAGE and cRAGE were 2318 ± 1224, 649 ± 454 and 1669 ± 901 pg/mL. The mean value of cRAGE/esRAGE was 2.82 ± 0.96. AGE were 3026 ± 766 AU and MIS 6.0 ± 4.7. eGFR correlated negatively with AGE, sRAGE, esRAGE and cRAGE, but not with cRAGE/esRAGE. Twenty-eight patients died. No difference was observed between diabetic and non-diabetic patients. Starting dialysis was not associated with enhanced risk of death. AGE, esRAGE and cRAGE/esRAGE were independently associated with all-cause mortality. AGE, esRAGE and cRAGE/esRAGE may help to stratify overall mortality risk. Implementing the clinical evaluation of CKD patients by quantifying these biomarkers can help to improve patient outcomes.

Therapeutic application of nutraceuticals in diabetic nephropathy: Current evidence and future implications

Diabetes mellitus (DM) is a common metabolic disease which may cause several complications, such as diabetic nephropathy (DN). The routine medical treatments used for DM are not effective enough and have many undesirable side effects. Moreover, the global increased prevalence of DM makes researchers try to explore potential complementary or alternative treatments. Nutraceuticals, as natural products with pharmaceutical agents, have a wide range of therapeutic properties in various pathologic conditions such as DN. However, the exact underlying mechanisms have not been fully understood. The purpose of this review is to summarize recent findings on the effect of nutraceuticals on DN.

Resveratrol: Evidence for Its Nephroprotective Effect in Diabetic Nephropathy

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Dietary habits play a major role in determining the onset and progression of DM-related disorders and a proper diet (rich in fruits and vegetables) can delay or prevent the process of DM pathogenesis. Thus, increasing attention has been paid to polyphenols and polyphenol-rich foods since their increased intake has been associated with a reduced incidence of DM and its associated complications. Resveratrol is a polyphenolic phytoalexin that is mainly found in grapevines and berries. It is available in various pharmaceutical dosages and is widely recommended as a dietary supplement due to its beneficial effects. Remarkably, resveratrol's capability to effectively lower blood glucose levels without any side effects has been amply demonstrated in many in vitro and in vivo studies. Herein, we comprehensively review and discuss the nephroprotective effect of resveratrol during DN and its associated mechanisms. Resveratrol exerts its nephroprotective effects via various mechanisms including reducing oxidative stress and advanced glycation end-product (AGE) production, stimulating autophagy, inhibiting endoplasmic reticulum (ER) stress and inflammation, ameliorating lipotoxicity, activating the AMP kinase (AMPK) pathway, and modulating angiogenesis. Moreover, the use of resveratrol as an adjuvant to conventional antidiabetic therapies could be an effective approach to manage DN in humans. However, evidence is scarce to support whether resveratrol has beneficial effects in humans during DN. Therefore, clinical studies are warranted to elucidate resveratrol's role against DN.

Preventive Role of Resveratrol Against Inflammatory Cytokines and Related Diseases

BACKGROUND

Immunity is the ultimate barrier between foreign stimuli and a host cell. Unwanted immune responses can threaten the host cells and may eventually damage a vital organ. Overproduction of inflammatory cytokines may also lead to autoimmune diseases. Inflammatory cells and pro-inflammatory cytokines can eventually progress to renal, cardiac, brain, hepatic, pancreatic and ocular inflammation that can result in severe damage in the long run. Evidence also suggests that inflammation may lead to atherosclerosis, Alzheimer's, hypertension, stroke, cysts and cancers.

METHODS

This study was designed to correlate the possible molecular mechanisms for inflammatory diseases and prevent biochemical changes owing to inflammatory cytokines by using Resveratrol. Therefore, we searched and accumulated very recent literature on inflammatory disorders and Resveratrol. We scoured PubMed, Scopus, Science Direct, PLoS One and Google Scholar to gather papers and related information.

RESULTS

Reports show that inflammatory diseases are very complex, as multiple cascade systems are involved; therefore, they are quite difficult to cure. However, our literature search also correlates some possible molecular interactions by which inflammation can be prevented. We noticed that Resveratrol is a potent lead component and has multiple activities against harmful inflammatory cytokines and related microRNA. Our study also suggests that the anti-inflammatory properties of Resveratrol have been highly studied on animal models, cell lines and human subjects and proven to be very effective in reducing inflammatory cell production and pro-inflammatory cytokine accumulation. Our tables and figures also demonstrate recent findings and possible preventive activities to minimize inflammatory diseases.

CONCLUSION

This study would outline the role of harmful inflammatory cytokines as well as how they accelerate pathophysiology and progress to an inflammatory disorder. Therefore, this study might show a potential therapeutic value of using Resveratrol by health professionals in preventing inflammatory disorders.

Quercetin liposomes ameliorate streptozotocin-induced diabetic nephropathy in diabetic rats

The effects of quercetin liposomes (Q-PEGL) on streptozotocin (STZ)-induced diabetic nephropathy (DN) was investigated in rats. Male Sprague Dawley rats were used to establish a STZ induced DN model. DN rats randomly received one of the following treatments for 8 weeks: blank treatment (DN), free quercetin (Que), pegylated liposomes (PEGL) and pegylated quercetin liposomes (Q-PEGL). A group of healthy rats served as the normal control. The fasting blood glucose (FBG), body weights (BWs), renal hypertrophy index (rHI), serum and urine biochemistry, renal histopathology, oxidative stress and immunohistochemical measurements of AGEs were analyzed to compare the effect of different treatments. Que and Q-PEGL significantly improved DN biochemistry and pathological changes, although the treated rats still had some symptoms of DN. The therapeutic effect of Q-PEGL surpassed that of Que. Pegylated quercetin liposomes allow maintaining higher quercetin concentrations in plasma than non-encapsulated quercetin. In conclusion the use of quercetin liposomes allows to reduce disease symptoms in a rat model of DN.

The Coming Age of Flavonoids in the Treatment of Diabetic Complications

Diabetes mellitus (DM), and its micro and macrovascular complications, is one of the biggest challenges for world public health. Despite overall improvement in prevention, diagnosis and treatment, its incidence is expected to continue increasing over the next years. Nowadays, finding therapies to prevent or retard the progression of diabetic complications remains an unmet need due to the complexity of mechanisms involved, which include inflammation, oxidative stress and angiogenesis, among others. Flavonoids are natural antioxidant compounds that have been shown to possess anti-diabetic properties. Moreover, increasing scientific evidence has demonstrated their potential anti-inflammatory and anti-oxidant effects. Consequently, the use of these compounds as anti-diabetic drugs has generated growing interest, as is reflected in the numerous in vitro and in vivo studies related to this field. Therefore, the aim of this review is to assess the recent pre-clinical and clinical research about the potential effect of flavonoids in the amelioration of diabetic complications. In brief, we provide updated information concerning the discrepancy between the numerous experimental studies supporting the efficacy of flavonoids on diabetic complications and the lack of appropriate and well-designed clinical trials. Due to the well-described beneficial effects on different mechanisms involved in diabetic complications, the excellent tolerability and low cost, future randomized controlled studies with compounds that have adequate bioavailability should be evaluated as add-on therapy on well-established anti-diabetic drugs.

Resveratrol prevents diabetic nephropathy by reducing chronic inflammation and improving the blood glucose memory effect in non-obese diabetic mice

Chronic inflammation plays an important role in the development of diabetic nephropathy. Advanced glycation end product receptor (RAGE), nuclear factor kappa B (NF-κB) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) are involved in the development of inflammation. Resveratrol is a plant antitoxin; it is believed to have anti-inflammatory effects and can improve blood glucose. We speculate that resveratrol treatment can protect renal function by reducing blood glucose, decreasing the expression of inflammatory factors. Non-obese diabetic (NOD) mice were randomly divided into three groups: T1DM, insulin (INS) and resveratrol (Res) groups. Mice without diabetes were classified as the non-diabetic control group (NOD-C group). The blood glucose (BG) level, blood urea nitrogen (BUN) level, serum creatinine (SCr) level and 24-h urinary microalbumin quantitative (UMA) were measured. The glomerulosclerosis index and basement membrane thickness were calculated under light and electron microscopes. The expression levels of RAGE, NF-кB (P65) and NOX4 in renal tissues were detected by Western blot analysis. We found that resveratrol treatment significantly reduced blood glucose within 28 days of the experiment, but the hypoglycemic effect was not lasting. At the same time, resveratrol reduced BUN, SCr, 24 h UMA and the expression of the inflammatory factors RAGE, NF-кB (P65) and NOX4 and improved the renal pathological structure. We believe that resveratrol improves renal function not only by its anti-inflammatory effect but also by improving the metabolic memory of hyperglycemia.

Can Medicinal Plants and Bioactive Compounds Combat Lipid Peroxidation Product 4-HNE-Induced Deleterious Effects?

The toxic reactive aldehyde 4-hydroxynonenal (4-HNE) belongs to the advanced lipid peroxidation end products. Accumulation of 4-HNE and formation of 4-HNE adducts induced by redox imbalance participate in several cytotoxic processes, which contribute to the pathogenesis and progression of oxidative stress-related human disorders. Medicinal plants and bioactive natural compounds are suggested to be attractive sources of potential agents to mitigate oxidative stress, but little is known about the therapeutic potentials especially on combating 4-HNE-induced deleterious effects. Of note, some investigations clarify the attenuation of medicinal plants and bioactive compounds on 4-HNE-induced disturbances, but strong evidence is needed that these plants and compounds serve as potent agents in the prevention and treatment of disorders driven by 4-HNE. Therefore, this review highlights the pharmacological basis of these medicinal plants and bioactive compounds to combat 4-HNE-induced deleterious effects in oxidative stress-related disorders, such as neurotoxicity and neurological disorder, eye damage, cardiovascular injury, liver injury, and energy metabolism disorder. In addition, this review briefly discusses with special attention to the strategies for developing potential therapies by future applications of these medicinal plants and bioactive compounds, which will help biological and pharmacological scientists to explore the new vistas of medicinal plants in combating 4-HNE-induced deleterious effects.

Comparison of the crystal structures and physicochemical properties of novel resveratrol cocrystals

Resveratrol (RSV) is one of the most extensively investigated natural polyphenol with potential cardioprotective effects and various biological activities. However, the polymorphism and solvates of RSV cocrystals have not been studied comprehensively. In addition, the relationship between the crystal packing modes and their physicochemical properties of RSV cocrystals remains poorly understood. In this paper, seven novel RSV cocrystals were prepared and characterized by powder X-ray diffraction, single-crystal X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic vapor sorption, Raman and Fourier transform infrared spectroscopy. Five RSV–4,4′-vinylenedipyridine (DPE) cocrystals were synthesized with polymorphs and solvates, such as RSV–DPE (1:2) in form (I) [RSV–2DPE form (I)], RSV–DPE (1:2) in form (II) [RSV–2DPE form (II)], RSV–DPE (1:1) (RSV–DPE), RSV–DPE (2:3)·acetone (RSV–1.5DPE·0.5ACE), RSV–DPE (1:1.5)·MeOH (RSV–1.5DPE·MeOH). However, RSV–4,4′-ethylenedipyridine (BPE) and RSV–4,4′-azobispyridine (AZPY) cocrystals were prepared as their single crystal forms, that is, RSV–BPE (1:1.5) (RSV–1.5BPE) and RSV–AZPY (1:2) (RSV–2AZPY). RSV–2DPE form (II) can be transformed from RSV–2DPE form (I) during the heating process from single crystal to single crystal. The physicochemical properties of RSV cocrystals are closely related to their crystal packing modes. Also, the conformation and molecular packing of RSV among different cocrystals is flexible. The solubility of RSV–1.5BPE and RSV–2DPE form (II) exhibit higher than RSV in the buffer solution of pH 4.6 and 2.0, respectively. This study may provide a valuable insight into the crystal packing modes of cocrystals which may affect their physicochemical properties.

The Signaling of Cellular Senescence in Diabetic Nephropathy

Diabetic nephropathy is the leading cause of chronic kidney disease (CKD) in western countries. Notably, it has a rapidly rising prevalence in China. The patients, commonly complicated with cardiovascular diseases and neurologic disorders, are at high risk to progress into end-stage renal disease (ESRD) and death. However, the pathogenic mechanisms of diabetic nephropathy have not been determined. Cellular senescence, which recently has gained broad attention, is thought to be an important player in the onset and development of diabetic nephropathy. In this issue, we generally review the mechanisms of cellular senescence in diabetic nephropathy, which involve telomere attrition, DNA damage, epigenetic alterations, mitochondrial dysfunction, loss of Klotho, Wnt/β-catenin signaling activation, persistent inflammation, and accumulation of uremic toxins. Moreover, we highlight the potential therapeutic targets of cellular senescence in diabetic nephropathy and provide important clues for clinical strategies.

Protective effect of umbilical cord mesenchymal stem cells combined with resveratrol against renal podocyte damage in NOD mice

BACKGROUND

The role of chronic inflammation initiated by persistent hyperglycemia in podocyte injury has attracted increasing attention. The advanced glycation end products (RAGE) receptor- nuclear factor-kappa B (NF-кB) signaling pathway is involved in the occurrence of inflammation. We speculate that treatment with human umbilical cord mesenchymal stem cells (hUCMSCs) combined with resveratrol can block this signaling pathway and protect podocyte function.

METHODS

Non obesity diabetes(NOD) mice were randomly divided into 5 groups: NOD-T1DM, Res, hUCMSCs, hUCMSCs + Res and insulin (INS)groups. Mice without diabetes were classified as NOD control group(NOD group). Blood glucose(BG), blood urea nitrogen(BUN), serum creatinine(SCr), 24-h urine albumin excretion rate (UAER) were measured. The expression of nephrin, WT1 and RAGE, MCP-1 in renal tissues were detected by Western blot, expression of NF-кB protein(P65) was determined by immunohistochemistry.

RESULTS

The combined treatment of hUCMSCs and Resveratrol can reduce BG, BUN, SCr, 24-h UAER, and the expression of the inflammatory factors MCP-1, RAGE and NF-кB; increase the number of podocytes and the expression of the podocyte-related proteins nephrin and WT1 in type 1 diabetes mellitus, and improve renal pathological structure.

CONCLUSIONS

Combining of hUCMSCs and resveratrol can better protect renal podocyte function, and the effects on the reduction of blood glucose and renal injury are better than those obtained by insulin treatment. This indicated that the combination of Res and hUCMSCs may be a novel therapeutic method for the treatment of DN.

The impact of resveratrol on toxicity and related complications of advanced glycation end products: A systematic review

Accumulation of advanced glycation end products (AGEs) promotes the generation of free radicals, which leads to chronic oxidative stress predisposing to chronic oxidative stress, inflammation, and related diseases. This systematic review aimed to determine the effect of resveratrol (RSV) on AGE-induced toxicity and its deleterious consequences. A comprehensive search was performed through literature were published until December 2018 using relevant keywords. The databases that were used for the search were PubMed, Scopus, Embase, ProQuest, and Google Scholar. A total of 29 eligible studies were found and included in the review for the analysis. Except one, all studies showed suppressing effects for RSV on the production of AGEs or receptor for advanced glycation end products (RAGE) and its detrimental consequences including oxidative stress, inflammatory response, cellular immune reactions, insulin response, and atherosclerosis. RSV exerts its effects through influencing RAGE, nuclear factor kappa B (NF-κB), peroxisome proliferator-activated receptor (PPAR) γ, and transforming growth factor (TGF)-β activities. This review suggests that RSV has got potential to decrease AGEs toxicity and inhibit the AGE-induced complications. More clinical trials are suggested to evaluate the beneficial effect of RSV on AGEs in chronic metabolic diseases.

Dicarbonyl Stress at the Crossroads of Healthy and Unhealthy Aging

Dicarbonyl stress occurs when dicarbonyl metabolites (i.e., methylglyoxal, glyoxal and 3-deoxyglucosone) accumulate as a consequence of their increased production and/or decreased detoxification. This toxic condition has been associated with metabolic and age-related diseases, both of which are characterized by a pro-inflammatory and pro-oxidant state. Methylglyoxal (MGO) is the most reactive dicarbonyl and the one with the highest endogenous flux. It is the precursor of the major quantitative advanced glycated products (AGEs) in physiological systems, arginine-derived hydroimidazolones, which accumulate in aging and dysfunctional tissues. The aging process is characterized by a decline in the functional properties of cells, tissues and whole organs, starting from the perturbation of crucial cellular processes, including mitochondrial function, proteostasis and stress-scavenging systems. Increasing studies are corroborating the causal relationship between MGO-derived AGEs and age-related tissue dysfunction, unveiling a previously underestimated role of dicarbonyl stress in determining healthy or unhealthy aging. This review summarizes the latest evidence supporting a causal role of dicarbonyl stress in age-related diseases, including diabetes mellitus, cardiovascular disease and neurodegeneration.

Health Benefits of Resveratrol in Kidney Disease: Evidence from In Vitro and In Vivo Studies

Different diseases and disorders that affect the kidneys include, but are not limited to, glomerulonephritis, diabetic nephropathy, polycystic kidney disease, kidney stones, renal fibrosis, sepsis, and renal cell carcinoma. Kidney disease tends to develop over many years, making it difficult to identify until much later when kidney function is severely impaired and undergoing kidney failure. Although conservative care, symptom management, medication, dialysis, transplantation, and aggressive renal cancer therapy are some of the current strategies/approaches to kidney disease treatment, new preventative targeted therapies are needed. Epidemiological studies have suggested that a diet rich in fruits and vegetables is associated with health benefits including protection against kidney disease and renal cancer. Resveratrol, a polyphenol found in grapes and berries, has been reported to have antioxidant, anti-inflammatory, antidiabetic, hepatoprotective, neuroprotective, and anti-cancer properties. The current review summarizes the existing in vitro and in vivo animal and human studies examining the nephroprotective effects of resveratrol.

Protective effect of the ethanol extract from Ligusticum chuanxiong rhizome against streptozotocin-induced diabetic nephropathy in mice

ETHNOPHARMACOLOGY RELEVANCE

Rhizome of Ligusticum chuanxiong Hort. (Abbreviated as LC) is a frequently prescribed component in plenty of traditional Chinese medicine (TCM) formulas which are used to treat diabetic nephropathy (DN). The aims of the present study are to investigate the protective effect of the ethanol extract of LC rhizome (EEL) against DN in vivo, evaluate its potential mechanism, and find the evidence supporting its enthopharmacological use as an anti-DN agent.

MATERIALS AND METHODS

Hepa 1c1c7 murine hepatoma cells, human breast carcinoma MDA-MB-231 cells, human renal glomerular endothelial cells (HRGEC), and RAW 264.7 murine macrophages were adopted to test the effects of EEL and its active constituents on inhibitions of oxidative stress and inflammation in vitro. A streptozotocin (STZ) -induced DN C57BL/6 mice model was established and used to investigate the preventive effect of EEL against DN in vivo.

RESULTS

EEL demonstrated potential inhibitory effects against oxidative stress and inflammation in vitro. Using a STZ-induced DN mice model, it has been found that EEL treatment significantly prevented STZ-induced increases of urine production, urinary albumin excretion (UAE) and urine albumin-to-creatinine ratio (UACR), and markedly attenuated STZ-induced renal damages (e.g. glomerulosclerosis and fibrosis). The predominant bioactive constituents, Z-ligustilide (LGT), ferulic acid (FA), and tetramethylpyrazine (TMP), were inhibitors of oxidative stress and inflammation through acting with Nrf2 and NF-κB pathways.

CONCLUSIONS

EEL attenuates structural and functional damages of kidney in STZ-induced DN model in vivo, which might be related to the functions of EEL on inhibitions of oxidative stress and inflammation. These finding definitely supports the ethnopharmacological use of LC as an anti-DN agent.

Resveratrol: from enhanced biosynthesis and bioavailability to multitargeting chronic diseases

Resveratrol, a phytoalexin with a wide range of pharmacological properties is synthesised by plants in response to stress, injury, infection or UV radiations. As it is a secondary metabolite with many health promoting properties, various methods employing microorganisms and genetic manipulation of different synthetic enzymes, have been comprehensively studied to increase its production. Its rapid metabolism and low bioavailability have been addressed by the use of bio enhancers and nano-formulations. This flavonoid is extensively researched due to its pharmacological properties such as anti-oxidative, anti-inflammatory and immuno-modulating effects. Knowledge of these properties of resveratrol has led to elaborate studies on its effect on diabetes, neurodegenerative diseases, cancer, ageing, obesity and cardiovascular diseases. At molecular level it targets sirtuin, adenosine monophosphate kinase, nuclear Factor-κB, inflammatory cytokines, anti-oxidant enzymes along with cellular processes such as angiogenesis, apoptosis, mitochondrial biogenesis, gluconeogenesis and lipid metabolism. This review discusses the properties of resveratrol and the different approaches of addressing the unfavourable synthesis and pharmacokinetics of this stilbene. Pre-clinical evaluations of resveratrol on diabetes mellitus, cardiovascular and neurological diseases are elaborately discussed and the underlying pathways involved in its therapeutic activity have been given paramount importance. Following the pre-clinical studies, clinical trials on the same reveal the efficacy of resveratrol in the effective management of these diseases. This review provides an intricate insight on resveratrol's significance from a dietary component to a therapeutic agent.

Eucalyptol Inhibits Advanced Glycation End Products-Induced Disruption of Podocyte Slit Junctions by Suppressing Rage-Erk-C-Myc Signaling Pathway

SCOPE

The maintenance of interpodocyte slit diaphragm is critical in the sieving function of glomerular filtration barrier. Eucalyptol is a natural constituent in aromatic plants with antioxidant properties. This study investigates whether and how eucalyptol inhibits podocyte slit diaphragm malfunction in glucose-exposed podocytes and diabetic mouse kidneys.

METHODS AND RESULTS

Podocytes were incubated in media containing 33 mm glucose with 1-20 μm eucalyptol. The in vivo model employed db/db mice orally administrated with 10 mg kg^-1 eucalyptol. Nontoxic eucalyptol enhanced podocyte expression of nephrin, podocin, FAT-1, CD2AP, and α-actinin-4 diminished by glucose. Oral administration of eucalyptol augmented the induction of the slit diaphragm proteins, α-actinin-4, and integrin β1 in diabetic kidneys, and ameliorated glomerular fibrosis and foot process effacement. Eucalyptol counteracted the receptor of advanced glycation end products (RAGE) induction in podocytes with glucose or AGE-BSA, and elevated the reduction of the slit diaphragm proteins by AGE-BSA. Eucalyptol attenuated the RAGE induction and AGE accumulation in diabetic kidneys. The blockade of ERK-c-Myc signaling enhanced the nephrin and CD2AP expression downregulated in AGE-exposed podocytes. These results indicate that eucalyptol blocked glucose-induced AGE-RAGE axis and podocyte injury through disturbing RAGE-ERK-c-Myc signaling.

CONCLUSION

Eucalyptol may be a potent agent antagonizing diabetes-associated malformation of interpodocyte slit junction and podocyte actin cytoskeleton.

Anti-Diabetic Effects of Acankoreagenin from the Leaves of Acanthopanax Gracilistylus Herb in RIN-m5F Cells via Suppression of NF-κB Activation

Diabetes mellitus is a chronic degenerative disease that causes long-term complications and represents a serious public health problem. In this manuscript, acankoreagenin isolated from the leaves of Acanthopanax gracilistylus (LAG) is thought to possess excellent anti-diabetic properties. In vitro, anti-diabetic activities were assessed based on the inhibitory activities with α-glucosidase (IC₅₀ 13.01 μM), α-amylase (IC₅₀ 30.81 μM), and PTP1B (IC₅₀ 16.39 μM). Acankoreagenin showed better anti-diabetic effects. Then, an investigation was performed to analyze the insulin secretion effects of the insulin-secreting cell line in RIN-m5F cells. It was found that acankoreagenin could increase the insulin release in RIN-m5F cells. It was also found that acankoreagenin reduced NO production, activity of caspase-3, and the reactive oxygen species levels in the cells injured by processing of cytokines. In western blotting, inactivation of NF-κB signaling was confirmed. Acankoreagenin (20 μM) showed a higher I-κBα expression and lower NF-κB expression than the control group and showed a better expression than the positive control L-NAME (1 mM) (p < 0.05). This study demonstrates the anti-diabetic effects of acankoreagenin in vitro and suggests acankoreagenin might offer therapeutic potential for treating diabetes mellitus.