Involvement of oxidative stress in the pathogenesis of diabetes

Beyond insulin: Unraveling the complex interplay of ER stress, oxidative damage, and CFTR modulation in CFRD

CF-related diabetes (CFRD) is a prevalent comorbidity in people with Cystic Fibrosis (CF), significantly impacting morbidity and mortality rates. This review article critically evaluates the current understanding of CFRD molecular mechanisms, including the role of CFTR protein, oxidative stress, unfolded protein response (UPR) and intracellular communication. CFRD manifests from a complex interplay between exocrine pancreatic damage and intrinsic endocrine dysfunction, further complicated by the deleterious effects of misfolded CFTR protein on insulin secretion and action. Studies indicate that ER stress and subsequent UPR activation play critical roles in both exocrine and endocrine pancreatic cell dysfunction, contributing to β-cell loss and insulin insufficiency. Additionally, oxidative stress and altered calcium flux, exacerbated by CFTR dysfunction, impair β-cell survival and function, highlighting the significance of antioxidant pathways in CFRD pathogenesis. Emerging evidence underscores the importance of exosomal microRNAs (miRNAs) in mediating inflammatory and stress responses, offering novel insights into CFRD's molecular landscape. Despite insulin therapy remaining the cornerstone of CFRD management, the variability in response to CFTR modulators underscores the need for personalized treatment approaches. The review advocates for further research into non-CFTR therapeutic targets, emphasizing the need to address the multifaceted pathophysiology of CFRD. Understanding the intricate mechanisms underlying CFRD will pave the way for innovative treatments, moving beyond insulin therapy to target the disease's root causes and improve the quality of life for individuals with CF.

AMPK pathway: an emerging target to control diabetes mellitus and its related complications

Purpose

In this extensive review work, the important role of AMP-activated protein kinase (AMPK) in causing of diabetes mellitus has been highlighted. Structural feature of AMPK as well its regulations and roles are described nicely, and the association of AMPK with the diabetic complications like nephropathy, neuropathy and retinopathy are also explained along with the connection between AMPK and β-cell function, insulin resistivity, mTOR, protein metabolism, autophagy and mitophagy and effect on protein and lipid metabolism.

Methods

Published journals were searched on the database like PubMed, Medline, Scopus and Web of Science by using keywords such as AMPK, diabetes mellitus, regulation of AMPK, complications of diabetes mellitus, autophagy, apoptosis etc.

Result

After extensive review, it has been found that, kinase enzyme like AMPK is having vital role in management of type II diabetes mellitus. AMPK involve in enhance the concentration of glucose transporter like GLUT 1 and GLUT 4 which result in lowering of blood glucose level in influx of blood glucose into the cells; AMPK increases the insulin sensitivity and decreases the insulin resistance and further AMPK decreases the apoptosis of β-cells which result into secretion of insulin and AMPK is also involve in declining of oxidative stress, lipotoxicity and inflammation, owing to which organ damage due to diabetes mellitus can be lowered by activation of AMPK.

Conclusion

As AMPK activation leads to overall control of diabetes mellitus, designing and developing of small molecules or peptide that can act as AMPK agonist will be highly beneficial for control or manage diabetes mellitus.

NIR-I emissive cyanine derived molecular probe for selective monitoring of hepatic albumin levels during hyperglycemia

In this study, we report a small molecule optical marker BI-CyG derived from the structural engineering of a cyanine scaffold. The developed probe offers suitable advantages over existing cyanine-based albumin specific probes in terms of its excitation and emission wavelengths, which are 760 and 830-832 nm, respectively. Structural tuning of the cyanine architecture leading to extended π-conjugation and resulting in a suitable bathochromic shift in the emission wavelength of the probe is represented in this study. The probe besides emitting in the NIR region, also possesses the desirable characteristics of being a potential target selective optical marker, as established from various biophysical studies. Molecular modelling and simulation studies provided critical insights into the binding of the probe in the protein microenvironment, which was further supported by experimental studies. The probe displayed intracellular albumin selectivity and was utilized for demonstrating alteration in albumin levels in pathological states such as hyperglycemia in hepatic cells. The present study also sheds some light on using BI-CyG as an imaging probe and on the role of metformin as a suitable drug for balancing hyperglycemia-induced reduced intra-hepatic albumin levels. The study, thus, attempts to highlight the structural derivatization of cyanine to afford a potential probe for serum albumin and its deployment to image altering albumin levels in an induced pathological condition, hyperglycemia.

Mendelian randomisation highlights type 1 diabetes as a causal determinant of idiopathic pulmonary fibrosis

BACKGROUND

It is unclear whether type 1 diabetes (T1D) causes idiopathic pulmonary fibrosis (IPF), despite observational research linking the two conditions. Therefore, our study aimed to examine the causal link between T1D and the likelihood of IPF by employing the Mendelian randomization (MR) technique of two-sample Mendelian randomization.

METHODS

Using data from two genome-wide association studies (GWAS) with European ancestry, we performed a two-sample MR analysis. These studies involved 18,856 individuals (6,683 cases and 12,173 controls) for T1D and 198,014 individuals (10,028 cases and 196,986 controls) for IPF. We utilized inverse-variance weighted (IVW) analysis as our main approach to determine the association between the risk of IPF and T1D. To evaluate multidirectionality, the MR-Egger regression test was utilized, whereas heterogeneity was assessed using Cochran's Q test. Additionally, a leave-one-out analysis was performed to assess the reliability of the results.

RESULTS

38 SNPs linked to T1D were employed as instrumental variables (IVs). Multiple MR methods yielded consistent results, and the MR analysis reveals a significant and positive causal impact of T1D on IPF (MR-IVW, odds ratio [OR] = 1.128, 95% confidence interval [CI] 1.034-1.230; P = 0.006). The limitations of the study include the lack of data from non-European groups and the inability to rule out the possibility of small links. Larger MR experiments are necessary to investigate minute impacts.

CONCLUSIONS

The results of this study provide evidence that T1D contributes to the onset and advancement of IPF. This finding may provide important insights into the cause of IPF and possible treatments in the future.

Association of urinary polycyclic aromatic hydrocarbon metabolites with gestational diabetes mellitus and gestational hypertension among pregnant women in Southwest China: A cross-sectional study

The association of polycyclic aromatic hydrocarbons (PAHs) with gestational diabetes mellitus (GDM) and gestational hypertension during pregnancy has not yet been established. To investigate the association between PAH exposure and GDM and gestational hypertension, we conducted a cross-sectional study of 4206 pregnant women from the Zunyi birth cohort in southwestern China. Gas chromatography/mass spectrometry was used to detect the urinary levels of 10 monohydroxylated PAHs (OH-PAHs). GDM and gestational hypertension were diagnosed and the relevant information was documented by specialist obstetricians and gynecologists. Logistic regression and restricted cubic spline regression were employed to investigate their single and nonlinear associations. Stratified analyses of pregnancy and body mass index data were conducted to determine their moderating effects on the abovementioned associations. Compared with the first quartile of urinary ∑OH-PAHs, the third or fourth quartile in all study participants was associated with an increased risk of GDM (quartile 3: odds ratio [OR] = 1.35, 95% confidence interval [CI]: 1.03-1.77) and gestational hypertension (quartile 3: OR = 1.88, 95% CI: 1.26-2.81; quartile 4: OR = 1.58, 95% CI: 1.04-2.39), respectively. Nonlinear associations of 1-OH-PYR with GDM (cutoff level: 0.02 μg/g creatinine [Cr]) and 1-OH-PHE with gestational hypertension (cutoff level: 0.06 μg/g Cr) were also observed. In pregnant women with overweight or obesity, 1-OH-PHE and 3-OH-PHE were more strongly associated with gestational hypertension. Our results indicate that exposure to PAH during pregnancy may significantly increase the maternal risks of GDM and gestational hypertension; however, this finding still needs to be confirmed through larger-scale prospective studies and biological evidence.

Natural exosomes-like nanoparticles in mung bean sprouts possesses anti-diabetic effects via activation of PI3K/Akt/GLUT4/GSK-3β signaling pathway

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by hyperglycemia and insulin resistance. Mung bean sprouts are traditionally considered a "folk" hypoglycemic food and their pharmacological effects and underlying mechanisms warrant further investigation.

PURPOSE

This study aimed to investigate the anti-diabetic effects of the exosomes-like nanoparticles in mung bean sprouts (MELNs) and explore the related molecular mechanisms.

RESULTS

MELNs were isolated using a differential centrifugation-polyethylene glycol (PEG) method, and the identification of MELNs were confirmed by PAGE gel electrophoresis, agarose gel electrophoresis, thin-layer chromatography (TLC), and transmission electron microscopy (TEM). In the high-fat diet/streptozotocin (HFD/STZ) mouse model, MELNs ameliorated the progression of T2DM by increasing oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) results, decreasing the fasting blood glucose level, and reducing the serum triglycerides (TG) and total cholesterol (TC). Histopathological examinations indicated MELNs diminished inflammatory infiltration of hepatocytes and amplified the area of islet B cells. In addition, MELNs decreased the oxidative stress levels in liver tissue and had good biocompatibility. In vitro experiments verified that MELNs improved the viability of glucosamine (GlcN) induced insulin-resistant hepatocytes. Furthermore, this study also revealed that MELNs upregulated GLUT4 & Nrf2 and down-regulated GSK-3β via activating the PI3K/Akt signaling pathway, promoting the production of antioxidant enzymes, such as HO-1 and SOD, to reduce oxidative stress.

CONCLUSION

MELNs mitigated the progression of type 2 diabetes in HFD/STZ mouse model. The underlying molecular mechanism is related to PI3K/Akt/GLUT4/GSK-3β signaling pathway.

Redox regulation in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the most devastating complications of diabetes mellitus, where currently there is no cure available. Several important mechanisms contribute to the pathogenesis of this complication, with oxidative stress being one of the key factors. The past decades have seen a large number of publications with various aspects of this topic; however, the specific details of redox regulation in DKD are still unclear. This is partly because redox biology is very complex, coupled with a complex and heterogeneous organ with numerous cell types. Furthermore, often times terms such as "oxidative stress" or reactive oxygen species are used as a general term to cover a wide and rich variety of reactive species and their differing reactions. However, no reactive species are the same, and not all of them are capable of biologically relevant reactions or "redox signaling." The goal of this review is to provide a biochemical background for an array of specific reactive oxygen species types with varying reactivity and specificity in the kidney as well as highlight some of the advances in redox biology that are paving the way to a better understanding of DKD development and risk.

Selenium and vitamin E ameliorate lead acetate-induced hepatotoxicity in rats via suppression of oxidative stress, mRNA of heat shock proteins, and NF-kB production

BACKGROUND

Lead exposure results in a terrible rise in heat shock protein levels.

OBJECTIVE

This research was conducted to look at the effects of lead poisoning on heat shock response, oxidative stress, and inflammatory markers in albino rats, as well as the power of selenium and vitamin E to resist lead toxic effects.

METHODS

Eight groups of albino rats are used. Each group contained six rats where the first group represented the negative control, and the other groups were treated with olive oil, vitamin E, selenium, lead, (vitamin E + lead), (selenium + lead), and (vitamin E + selenium + lead). All the treatments lasted for 28 days. Then, the mRNA expression of interested heat shock proteins (HSP90, HSP70, and HSP60) was assessed. For oxidative stress disruption, we investigated nitric oxide (NO) and malondialdehyde (MDA) content, and enzymatic and non-enzymatic antioxidants activity respectively in rat livers.

RESULTS

our results revealed the synergetic protective effect of the combination of two antioxidants (vitamin E and selenium) against lead poising. This was clear in regulating HSPs expression, inflammatory markers, glucose, lipid profile, liver functions, and antioxidant enzymes more than the treatment with one antioxidant.

CONCLUSION

Pb is a toxic material that can induce HSPs and inflammatory markers expression. Selenium and vitamin E can give excellent effects in ameliorating Pb toxicity when used together.

Unraveling the Crosstalk between Lipids and NADPH Oxidases in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a serious complication of diabetes mellitus and a leading cause of end-stage renal disease. Abnormal lipid metabolism and intrarenal accumulation of lipids have been shown to be strongly correlated with the development and progression of diabetic kidney disease (DKD). Cholesterol, phospholipids, triglycerides, fatty acids, and sphingolipids are among the lipids that are altered in DKD, and their renal accumulation has been linked to the pathogenesis of the disease. In addition, NADPH oxidase-induced production of reactive oxygen species (ROS) plays a critical role in the development of DKD. Several types of lipids have been found to be tightly linked to NADPH oxidase-induced ROS production. This review aims to explore the interplay between lipids and NADPH oxidases in order to provide new insights into the pathogenesis of DKD and identify more effective targeted therapies for the disease.

6-Gingerol Ameliorates Hepatic Steatosis, Inflammation and Oxidative Stress in High-Fat Diet-Fed Mice through Activating LKB1/AMPK Signaling

6-Gingerol, one of the major pharmacologically active ingredients extracted from ginger, has been reported experimentally to exert hepatic protection in non-alcoholic fatty liver disease (NAFLD). However, the molecular mechanism remains largely elusive. RNA sequencing indicated the significant involvement of the AMPK signaling pathway in 6-gingerol-induced alleviation of NAFLD in vivo. Given the significance of the LKB1/AMPK pathway in metabolic homeostasis, this study aims to investigate its role in 6-gingerol-induced mitigation on NAFLD. Our study showed that 6-gingerol ameliorated hepatic steatosis, inflammation and oxidative stress in vivo and in vitro. Further experiment validation suggested that 6-gingerol activated an LKB1/AMPK pathway cascade in vivo and in vitro. Co-immunoprecipitation analysis demonstrated that the 6-gingerol-elicited activation of an LKB1/AMPK pathway cascade was related to the enhanced stability of the LKB1/STRAD/MO25 complex. Furthermore, radicicol, an LKB1 destabilizer, inhibited the activating effect of 6-gingerol on an LKB1/AMPK pathway cascade via destabilizing LKB1/STRAD/MO25 complex stability in vitro, thus reversing the 6-gingerol-elicited ameliorative effect. In addition, molecular docking analysis further predicated the binding pockets of LKB1 necessary for binding with 6-gingerol. In conclusion, our results indicate that 6-gingerol plays an important role in regulating the stability of the LKB1/STRAD/MO25 complex and the activation of LKB1, which might weigh heavily in the 6-gingerol alleviation of NAFLD.

Rainbow Trout (Oncorhynchus mykiss) as Source of Multifunctional Peptides with Antioxidant, ACE and DPP-IV Inhibitory Activities

The present study aimed at characterizing the possible biological activities of the multifunctional low molecular weight fractions (<3 kDa) peptides isolated from rainbow trout (Oncorhynchus mykiss) obtained by enzymatic hydrolysis. The fish protein hydrolysate (FPH) was tested for its antioxidant property along with its angiotensin converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. In particular, the 2,2-diphenyl-1-picrylhydrazyl (DPPH), the ferric reducing antioxidant power (FRAP), the oxygen radical absorbance capacity (ORAC) assay and the 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays were carried out for the evaluation of the in vitro antioxidant activity. The cell-free ACE and DPP-IV inhibitory activity assays were also estimated, showing a dose-dependent inhibition. These biological properties were additionally quantified at the cellular level using human intestinal Caco-2 cells. Namely, the antioxidant activity was determined by evaluating the capability of the hydrolysate to reduce the H₂O₂-induced reactive oxygen species (ROS) and lipid peroxidation levels, and the DPP-IV activity assays show a reduction of enzyme activity of up to 27.57 ± 3.7% at 5 mg/mL. The results indicate that Oncorhynchus mykiss-derived peptides may have potential employment as health-promoting ingredients.

Vitamin C supplementation for diabetes management: A comprehensive narrative review

Growing evidence suggests that vitamin C supplementation may be an effective adjunct therapy in the management of people with diabetes. This paper critically reviews the current evidence on effects of vitamin C supplementation and its potential mechanisms in diabetes management. Evidence from meta-analyses of randomized controlled trials (RCTs) show favourable effects of vitamin C on glycaemic control and blood pressure that may be clinically meaningful, and mixed effects on blood lipids and endothelial function. However, evidence is mostly of low evidence certainty. Emerging evidence is promising for effects of vitamin C supplementation on some diabetes complications, particularly diabetic foot ulcers. However, there is a notable lack of robust and well-designed studies exploring effects of vitamin C as a single compound supplement on diabetes prevention and patient-important outcomes (i.e. prevention and amelioration of diabetes complications). RCTs are also required to investigate potential preventative or ameliorative effects of vitamin C on gestational diabetes outcomes. Oral vitamin C doses of 500-1000 mg per day are potentially effective, safe, and affordable for many individuals with diabetes. However, personalisation of supplementation regimens that consider factors such as vitamin C status, disease status, current glycaemic control, vitamin C intake, redox status, and genotype is important to optimize vitamin C's therapeutic effects safely. Finally, given a high prevalence of vitamin C deficiency in patients with complications, it is recommended that plasma vitamin C concentration be measured and monitored in the clinic setting.

Sidestream Smoke Extracts from Harm-Reduction and Conventional Camel Cigarettes Inhibit Osteogenic Differentiation via Oxidative Stress and Differential Activation of intrinsic Apoptotic Pathways

Epidemiological studies suggest cigarette smoking as a probable environmental factor for a variety of congenital anomalies, including low bone mass, increased fracture risk and poor skeletal health. Human and animal in vitro models have confirmed hypomineralization of differentiating cell lines with sidestream smoke being more harmful to developing cells than mainstream smoke. Furthermore, first reports are emerging to suggest a differential impact of conventional versus harm-reduction tobacco products on bone tissue as it develops in the embryo or in vitro. To gather first insight into the molecular mechanism of such differences, we assessed the effect of sidestream smoke solutions from Camel (conventional) and Camel Blue (harm-reduction) cigarettes using a human embryonic stem cell osteogenic differentiation model. Sidestream smoke from the conventional Camel cigarettes concentration-dependently inhibited in vitro calcification triggered by high levels of mitochondrially generated oxidative stress, loss of mitochondrial membrane potential, and reduced ATP production. Camel sidestream smoke also induced DNA damage and caspase 9-dependent apoptosis. Camel Blue-exposed cells, in contrast, invoked only intermediate levels of reactive oxygen species insufficient to activate caspase 3/7. Despite the absence of apoptotic gene activation, damage to the mitochondrial phenotype was still noted concomitant with activation of an anti-inflammatory gene signature and inhibited mineralization. Collectively, the presented findings in differentiating pluripotent stem cells imply that embryos may exhibit low bone mineral density if exposed to environmental smoke during development.

Hydroxy-α-sanshool isolated from Zanthoxylum bungeanum Maxim. has antidiabetic effects on high-fat-fed and streptozotocin-treated mice via increasing glycogen synthesis by regulation of PI3K/Akt/GSK-3β/GS signaling

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by hyperglycemia. The fruits of Zanthoxylum bungeanum Maxim. is a common spice and herbal medicine in China, and hydroxy-α-sanshool (HAS) is the most abundant amide in Z. bungeanum and reported to have significant hypoglycemic effects. The purpose of this study was to evaluate the ameliorative effects of HAS on T2DM and the potential mechanisms responsible for those effects. An acute toxicity test revealed the median lethal dose (LD50) of HAS is 73 mg/kg. C57BL/6 J mice were fed a high-fat diet and given an intraperitoneal injection of streptozotocin (STZ) to induce T2DM in mice to evaluate the hypoglycemic effects of HAS. The results showed that HAS significantly reduced fasting blood glucose, reduced pathological changes in the liver and pancreas, and increased liver glycogen content. In addition, glucosamine (GlcN)-induced HepG2 cells were used to establish an insulin resistance cell model and explore the molecular mechanisms of HAS activity. The results demonstrated that HAS significantly increases glucose uptake and glycogen synthesis in HepG2 cells and activates the PI3K/Akt pathway in GlcN-induced cells, as well as increases GSK-3β phosphorylation, suppresses phosphorylation of glycogen synthase (GS) and increases glycogen synthesis in liver cells. Furthermore, these effects of HAS were blocked by the PI3K inhibitor LY294002. The results of our study suggest that HAS reduces hepatic insulin resistance and increases hepatic glycogen synthesis by activating the PI3K/Akt/GSK-3β/GS signaling pathway.

Glutathione Peroxidase 4 Is a Predictor of Diabetic Kidney Disease Progression in Type 2 Diabetes Mellitus

BACKGROUND

Diabetic kidney disease (DKD) represents a heavy burden in type 2 diabetes mellitus (T2DM). Ferroptosis plays an important role in DKD, and it thus provides new perspectives to pursue more related biomarkers to assess the disease severity and prognosis. Glutathione peroxidase 4 (GPX4) is the mainstay in regulating ferroptosis. The current study investigated the predictive value of kidney GPX4 expression level in DKD progression.

METHODS

We measured GPX4 levels in kidney paraffin sections of 85 biopsy-proven DKD patients by immunohistochemistry staining. The associations between the GPX4 level and clinicopathological parameters as well as renal outcomes were analyzed.

RESULTS

GPX4 is mainly expressed in kidney tubulointerstitium, especially in tubular epithelial cells of DKD patients. The GPX4 expression level was significantly lower in DKD patients than healthy controls. Besides, GPX4 level significantly correlated with proteinuria (r = -0.42, p < 0.001), urinary albumin-to-creatinine ratio (uACR) (r = -0.40, p < 0.01), serum creatinine (Scr) (r = -0.59, p < 0.001), estimated glomerular filtration rate (eGFR) (r = 0.66, p < 0.001), and the percentage of sclerosed glomeruli (r = -0.42, p < 0.001) in renal specimens. During follow-up, the GPX4 level positively correlated with eGFR slope (r = 0.48, p < 0.001), and GPX4-low patients showed a significantly higher probability of developing end-stage kidney disease (ESKD) compared with GPX4-high patients (p < 0.01). Moreover, after adjusting for other potential predictors, the GPX4 level was still an independent predictor of developing ESKD (HR 2.15, 95% CI 1.08 to 4.28, p < 0.05).

CONCLUSIONS

Kidney tubulointerstitial GPX4 expression level was associated with the disease severity and progression of DKD.

Ochratoxin A and Kidney Oxidative Stress: The Role of Nutraceuticals in Veterinary Medicine-A Review

The problem of residues of toxic contaminants in food products has assumed considerable importance in terms of food safety. Naturally occurring contaminants, such as mycotoxins, are monitored routinely in the agricultural and food industries. Unfortunately, the consequences of the presence of mycotoxins in foodstuffs are evident in livestock farms, where both subacute and chronic effects on animal health are observed and could have non-negligible effects on human health. Ochratoxin A (OTA) is a common mycotoxin that contaminates food and feeds. Due to its thermal stability, the eradication of OTA from the food chain is very difficult. Consequently, humans and animals are frequently exposed to OTA in daily life. In this review article, we will devote time to highlighting the redox-based nephrotoxicity that occurs during OTA intoxication. In the past few decades, the literature has improved on the main molecules and enzymes involved in the redox signaling pathway as well as on some new antioxidant compounds as therapeutic strategies to counteract oxidative stress. The knowledge shown in this work will address the use of nutraceutical substances as dietary supplements, which would in turn improve the prophylactic and pharmacological treatment of redox-associated kidney diseases during OTA exposure, and will attempt to promote animal feed supplementation.

Mechanism and effects of artesunate on the liver function of rats with type 1 diabetic periodontitis

Periodontitis is an inflammatory disease of the gums. Periodontitis in patients with diabetes can aggravate insulin resistance, but its molecular and biological mechanism remains unclear. This study aimed to explore the effects of diabetic periodontitis on liver function and determine the mechanism by which artesunate improves liver function. Rats with streptozotocin-induced diabetes were divided into five groups, i.e., normal control group (NC group), diabetic periodontitis group (DM+PD group), artesunate intervention group (ART group), insulin intervention group (INS group), and combined medication intervention group (ART+INS group). Drug interventions were then administered to the rats in each group as follows: 50 mg/kg artesunate to the ART group, 6 U/kg insulin to the INS group, and 50 mg/kg artesunate + 6 U/kg insulin to the ART+INS group. Blood samples, liver tissues, and the maxillary alveolar bone were collected post-sacrifice. ART was found to significantly ameliorate hyperglycemia, blood lipid levels, and liver function. The levels of inflammatory factors reduced; the effect was more pronounced in the ART+INS group. Artesunate presumably inhibits the TLR4/NF-κB signaling pathway and expression of downstream inflammatory factors, thereby exerting a protective effect on diabetes-related liver function. This offers a fresh approach to treat diabetes mellitus.

Advancements in nanomedicines for the detection and treatment of diabetic kidney disease

In the diabetic kidneys, morbidities such as accelerated ageing, hypertension and hyperglycaemia create a pro-inflammatory microenvironment characterised by extensive fibrogenesis. Radiological techniques are not yet optimised generating inconsistent and non-reproducible data. The gold standard procedure to assess renal fibrosis is kidney biopsy, followed by histopathological assessment. However, this method is risky, invasive, subjective and examines less than 0.01% of kidney tissue resulting in diagnostic errors. As such, less than 10% of patients undergo kidney biopsy, limiting the accuracy of the current diabetic kidney disease (DKD) staging method. Standard treatments suppress the renin-angiotensin system to control hypertension and use of pharmaceuticals aimed at controlling diabetes have shown promise but can cause hypoglycaemia, diuresis and malnutrition as a result of low caloric intake. New approaches to both diagnosis and treatment are required. Nanoparticles (NPs) are an attractive candidate for managing DKD due to their ability to act as theranostic tools that can carry drugs and enhance image contrast. NP-based point-of-care systems can provide physiological information previously considered unattainable and provide control over the rate and location of drug release. Here we discuss the use of nanotechnology in renal disease, its application to both the treatment and diagnosis of DKD. Finally, we propose a new method of NP-based DKD classification that overcomes the current systems limitations.

EW-7197 Attenuates the Progression of Diabetic Nephropathy in db/db Mice through Suppression of Fibrogenesis and Inflammation

BACKGROUND

Diabetic nephropathy (DN) is characterized by albuminuria and accumulation of extracellular matrix (ECM) in kidney. Transforming growth factor-β (TGF-β) plays a central role in promoting ECM accumulation. We aimed to examine the effects of EW-7197, an inhibitor of TGF-β type 1 receptor kinase (ALK5), in retarding the progression of DN, both in vivo, using a diabetic mouse model (db/db mice), and in vitro, in podocytes and mesangial cells.

METHODS

In vivo study: 8-week-old db/db mice were orally administered EW-7197 at a dose of 5 or 20 mg/kg/day for 10 weeks. Metabolic parameters and renal function were monitored. Glomerular histomorphology and renal protein expression were evaluated by histochemical staining and Western blot analyses, respectively. In vitro study: DN was induced by high glucose (30 mM) in podocytes and TGF-β (2 ng/mL) in mesangial cells. Cells were treated with EW-7197 (500 nM) for 24 hours and the mechanism associated with the attenuation of DN was investigated.

RESULTS

Enhanced albuminuria and glomerular morphohistological changes were observed in db/db compared to that of the nondiabetic (db/m) mice. These alterations were associated with the activation of the TGF-β signaling pathway. Treatment with EW-7197 significantly inhibited TGF-β signaling, inflammation, apoptosis, reactive oxygen species, and endoplasmic reticulum stress in diabetic mice and renal cells.

CONCLUSION

EW-7197 exhibits renoprotective effect in DN. EW-7197 alleviates renal fibrosis and inflammation in diabetes by inhibiting downstream TGF-β signaling, thereby retarding the progression of DN. Our study supports EW-7197 as a therapeutically beneficial compound to treat DN.

Exposure to polycyclic aromatic hydrocarbon-induced oxidative stress in Shiraz, Iran: urinary levels, health risk assessment and mediation effect of MDA on the risk of metabolic syndromes

PURPOSE

Polycyclic Aromatic Hydrocarbons (PAHs) have been identified as carcinogenic and endocrine disrupter compounds that cause Metabolic Syndrome (MetS). Oxidative stress can lead to carcinogenesis and MetS in exposed people. Therefore, the relationship between urinary metabolite of PAH (OH-PAHs) level and the oxidative stress biomarker (Malondialdehyde) effect as the mediator in increasing the risk of MetS due to PAH exposure and risk assessment was investigated in Shiraz, Iran.

METHODS

The first morning void urinary and blood samples were obtained from participants and analyzed. Physical examinations and anthropometric measurements were performed on the day of sampling. An automatic biochemistry analyzer was used to measure the blood cells. The participants' socio-demographic information was gathered using a questionnaire and direct interviews with participants.

RESULTS

The MetS prevalence was 26%. Malondialdehyde could act as a mediator between exposure to 1-HydroxyPyrene and increase in fast blood sugar, exposure to 2-HydroxyNaphthalene and increase in systolic blood pressure and exposure to 2-HydroxyFluorene and increase in SBP. Hazard quotients varied from 0.009 to 14.92 in women, and from 0.005 to 8.43 for Fluorene and Naphthalene in men, respectively. The Hazard Indexes were greater than one meaning that the non-cancer health risk related to the PAH exposure could be identified in the participants.

CONCLUSION

Although oxidative stress has been suggested to lead to MetS and the high HI levels obtained in the current study, future researches are essential to achieve more reliable findings and monitoring the environmental influencing factors in PAH exposure.

Glucose metabolism enhancement by 10-hydroxy-2-decenoic acid via the PI3K/AKT signaling pathway in high-fat-diet/streptozotocin induced type 2 diabetic mice

Here, we used high fat diet (HFD) combined with streptozotocin (STZ) injection to establish a diabetes model, with the aim of exploring the hypoglycemic effects of 10-hydroxy-2-decenoic acid (10-HDA), and...

Evaluation of Antidiabetic Properties of the Leaves Extract of Ficus vallis-choudae Delile in a Model of Type 2 Diabetes Induced by High-Fat Diet and Streptozotocin

This work aimed to determine the phytochemical composition of the aqueous extract of leaves of Ficus vallis-choudae (AEFV) and to evaluate its antidiabetic properties on a model of type 2 diabetes induced by a high-fat diet (HFD) and a low dose of streptozotocin (STZ). The phytochemical analysis was carried out according to several methods using the standard of each bioactive compound. Type 2 diabetes was induced by feeding rats for 4 weeks with HFD lard followed by injection of a low dose of STZ (35 mg/kg). After induction, the rats were divided into groups and treated for 28 days with metformin (40 mg/kg) and the AEFV at doses of 110, 220, and 440 mg/kg. The results showed that the AEFV contains saponins, flavonoids, tannins, and total polyphenols. In addition, it dramatically reduced body mass, body mass index (BMI), atherogenic index (AI), coronary heart risk index (CRI), and abdominal fat and increased homeostatic model assessment of β-cell function (HOMA-β), high-density lipoprotein cholesterol (HDL-c) levels, and cardioprotective index (CI). The AEFV also lowered blood glucose levels, insulinemia, homeostatic model assessment of insulin resistance (HOMA-IR) index, and total cholesterol (TC), triglycerides (TG), low-density lipoproteins cholesterol (LDL-c), and very-low-density lipoproteins cholesterol (VLDL-c) levels. There was a decrease in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity and in urea and serum creatinine levels following the administration of AEFV. The AEFV caused increased superoxide dismutase (SOD) and catalase (CAT) activities, reduced glutathione (GSH) levels, and decreased malondialdehyde (MDA) levels in the liver, kidneys, and heart of rats. The AEFV has hypoglycemic, antioxidant, and cardioprotective properties, thus validating its use in traditional medicine for the treatment of type 2 diabetes and its complications.

Oxidized lipid-associated protein damage in children and adolescents with type 1 diabetes mellitus: New diagnostic/prognostic clinical markers

BACKGROUND

Type 1 diabetes mellitus (DM1), a chronic metabolic disorder of autoimmune origin, has been associated with oxidative stress (OS), which plays a central role in the onset, progression, and long-term complications of DM1. The markers of OS lipid peroxidation products, lipid hydroperoxides (LOOH), and also malondialdehyde (MDA) and thiobarbituric reactive substances (TBARS) that oxidatively modify proteins (Pr) (i.e., PrMDA and PrTBARS, respectively), have been associated with DM2, DM1, diabetic neuropathy, and microalbuminuria.

OBJECTIVE/SUBJECTS

Here, we investigated LOOH, PrMDA and PrTBARS in 50 children and adolescents with DM1 and 21 controls.

RESULTS

The novel OS marker PrTBARS was assessed for the first time in children and adolescents with DM1. LOOH and the pair PrMDA/PrTBARS, representing early and late peroxidation stages, respectively, are found to be significantly higher (130%, 50/90%, respectively, at p < 0.001) in patients with DM1 compared to controls. The studied OS parameters did not differ with age, age at diagnosis, sex, duration of DM1, presence of recent ketosis/ketoacidosis, or mode of treatment.

CONCLUSIONS

We propose that LOOH, PrMDA and the new marker PrTBARS could serve as potential diagnostic clinical markers for identifying OS in children and adolescents with DM1, and may, perhaps, hold promise as a prognostic tool for future complications associated with the disease.

Effects of citral on serum antioxidant status and liver genes expressions of paraoxonase 1 and nitric oxide synthase in a rat model of streptozotocin-induced diabetes mellitus

Background:

Citral (C₁₀H₁₆O) is the main ingredient of Cymbopogon citratus (lemongrass oil) and can reduce the side effects of oxidative stress. Diabetes caused by insulin deficiency induces oxidative stress in the liver.

Aims:

This study aimed to investigate the ameliorative effects of citral on selected oxidative parameters and the gene expression of paraoxonase 1 (PON1) and endothelial nitric oxide synthase (eNOS) in a rat model of streptozotocin (STZ)-induced diabetes mellitus.

Methods:

Forty rats were divided into four groups at random: control (C), control citral (CC), and two STZ-induced diabetic groups (diabetic (D) and citral diabetic (CD)). After diabetes confirmation (day 7), gavage treatment with citral (300 mg/kg body weight (BW)) was started in the CD and CC groups and continued for two weeks.

Results:

On day 21 of the study, following treatment with citral for 14 days, the serum levels of total antioxidant capacity (TAC), and PON1 in the CD group were significantly increased compared to those in the D group (P<0.05). While treatment with citral caused a significant decrease in the Malondialdehyde (MDA), and eNOS in the CD group compared to those of the D group (P<0.001). The expression rate of liver PON1 gene was considerably upregulated in the CD group compared to that in the D group (P<0.001); while the opposite was observed for eNOS gene expression. However, there was no significant difference between the CC and C groups in terms of all examined parameters (P>0.05).

Conclusion:

This study showed positive effects of citral on serum antioxidant status and liver gene expression of PON1 and eNOS in diabetic rats.

Plasma activity of the antioxidant enzymes in predicting diabetic nephropathy progression

INTRODUCTION

The aim of the study was to examine whether biomarkers of oxidative stress are predictors of diabetic nephropathy (DN) progression.

METHODS

The study involved 45 patients with type 2 diabetes and DN and 15 healthy controls. Patients were followed for 3 years and the annual percentage change in eGFR was used to estimate the progression of DN. Patients with an annual percentage change in eGFR above the cutoff value of - 5.48%/year were classified in group 1, those with an annual percentage change in eGFR ≤ - 5.48%/year in group 2.

RESULTS

The 28 patients in group 1 had the annual percentage change in eGFR of - 4.78 and 39.12%/year, and for the 17 patients in group 2 it ranged from - 24.86 to - 6.18%/year. At the onset of the study no significant differences were found between the groups in demographic, clinical or laboratory parameters. Plasma activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) were significantly lower in patients than in the controls. During 3-year study kidney function and size changed insignificantly in group 1, while eGFR and kidney size decreased and proteinuria increased significantly in group 2. Multivariate linear regression analysis selected male gender, duration of diabetes, systolic blood pressure, fasting serum glucose, urine protein/creatinine ratio as factors associated with DN progression. Plasma activity of GPX and SOD were selected as positive predictors of annual percentage change in eGFR.

CONCLUSION

Besides already known factors, plasma activity of GPX and SOD were found to be significant independent predictors of DN progression.

Redox metabolism: ROS as specific molecular regulators of cell signaling and function

Redox reactions are intrinsically linked to energy metabolism. Therefore, redox processes are indispensable for organismal physiology and life itself. The term reactive oxygen species (ROS) describes a set of distinct molecular oxygen derivatives produced during normal aerobic metabolism. Multiple ROS-generating and ROS-eliminating systems actively maintain the intracellular redox state, which serves to mediate redox signaling and regulate cellular functions. ROS, in particular hydrogen peroxide (H₂O₂), are able to reversibly oxidize critical, redox-sensitive cysteine residues on target proteins. These oxidative post-translational modifications (PTMs) can control the biological activity of numerous enzymes and transcription factors (TFs), as well as their cellular localization or interactions with binding partners. In this review, we describe the diverse roles of redox regulation in the context of physiological cellular metabolism and provide insights into the pathophysiology of diseases when redox homeostasis is dysregulated.

Elevated Serum Levels of Ischemia Modified Albumin and Malondialdehyde are Related to Atherogenic Index of Plasma in a Cohort of Prediabetes

BACKGROUND

Prediabetes, defined as impaired glucose tolerance and/or impaired fasting glucose, is a risk factor for future type 2 diabetes, dyslipidemia, cardiovascular disease and all-cause mortality. High serum levels of ischemia modified albumin (IMA) and malondialdehyde (MDA) as oxidative stress markers were determined in diabetes, however, no studies have investigated these markers together in prediabetes. The aim of the present study was to investigate the circulating levels of both IMA and MDA in a cohort of prediabetic adults. The possible associations between both markers and the atherogenic index of plasma (AIP) were also evaluated.

METHODS

This study enrolled 100 adults with prediabetes and 50 healthy controls matched for age and sex. Anthropometric measurements, fasting and 2-hour post load glucose, glycosylated hemoglobin (A1c), lipids profile, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), high sensitivity C-reactive protein (hs-CRP), AIP, IMA and MDA were assessed.

RESULTS

IMA, MDA, hs-CRP and AIP were significantly higher in adults with prediabetes than in healthy controls. Male gender, fasting and post load glucose, A1c, fasting insulin, TGs, HDL-C, hs- CRP, AIP and MDA were independent predictor variables of IMA, whereas male gender, WC, fasting and post load glucose, A1c, fasting insulin, TC, TGs, LDL-C, HDL-C, hs-CRP and AIP were independent predictor variables of MDA.

CONCLUSION

The elevation of IMA concomitantly with MDA reflecting the antioxidant status in prediabetes, and their associations with hs-CRP and AIP should reinforce the idea of screening and treatment of prediabetes.

Nutrigenomics in Regulating the Expression of Genes Related to Type 2 Diabetes Mellitus

Nutrigenomics is the study of the gene-nutrient interaction and it indicates that some nutrients, called bioactive compounds, can mold the genetic expression or change the nucleotide chain. Polyphenols are secondary metabolites found in plants that are regularly consumed in functional foods and help prevent or delay the onset of type 2 diabetes mellitus (T2DM) and its complications. This article objected to review studies about the interaction of diet with polyphenols and Mediterranean diet in the expression of human genes related to T2DM. Resveratrol acts as an antioxidant, anti-inflammatory, and increases mitochondrial function. Regular consumption of quercetin resulted in improvement of hypertension and suppression of diabetes-induced vasoconstriction. Genistein also showed positive results in T2DM, such as increased cell mass and improved glucose tolerance and insulin levels. Catechins showed efficiency in inducing genes in triacylglycerol biosynthesis, inhibition of fatty acids and cholesterol, and resulting in their participation in mitigating complications of diabetes. Lastly, curcumin was demonstrated to be a protector of the pancreatic islets against streptozotocin-induced oxidative stress. Growing evidence suggest that bioactive compounds such as polyphenols have an important role in T2DM and the prevention and treatment of its complication, as they cause activation or inhibition of related genes.

Environmental pollution and diabetes mellitus

Diabetes mellitus (DM) is a chromic metabolic disease that affects a large segment of the population worldwide. Physical inactivity, poor nutrition, and genetic predisposition are main risk factors for disease development. In the last decade, it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents. Environmental pollution is exponentially increasing in uncontrolled manner in several countries. Environmental pollutants are of diverse nature and toxicities, including polyaromatic hydrocarbons (PAHs), pesticides, and heavy metals. In the current review, we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities. Finally, a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.

Diabetic Complications and Oxidative Stress: A 20-Year Voyage Back in Time and Back to the Future

Twenty years have passed since Brownlee and colleagues proposed a single unifying mechanism for diabetic complications, introducing a turning point in this field of research. For the first time, reactive oxygen species (ROS) were identified as the causal link between hyperglycemia and four seemingly independent pathways that are involved in the pathogenesis of diabetes-associated vascular disease. Before and after this milestone in diabetes research, hundreds of articles describe a role for ROS, but the failure of clinical trials to demonstrate antioxidant benefits and some recent experimental studies showing that ROS are dispensable for the pathogenesis of diabetic complications call for time to reflect. This twenty-year journey focuses on the most relevant literature regarding the main sources of ROS generation in diabetes and their role in the pathogenesis of cell dysfunction and diabetic complications. To identify future research directions, this review discusses the evidence in favor and against oxidative stress as an initial event in the cellular biochemical abnormalities induced by hyperglycemia. It also explores possible alternative mechanisms, including carbonyl stress and the Warburg effect, linking glucose and lipid excess, mitochondrial dysfunction, and the activation of alternative pathways of glucose metabolism leading to vascular cell injury and inflammation.

Relationship between heavy metal exposure and type 2 diabetes: a large-scale retrospective cohort study using occupational health examinations

OBJECTIVES

To investigate the associations between heavy metal exposure and serum ferritin levels, physical measurements and type 2 diabetes mellitus (DM).

DESIGN

A retrospective cohort study.

SETTING

Changwon, the location of this study, is a Korean representative industrial city. Data were obtained from medical check-ups between 2002 and 2018.

PARTICIPANTS

A total of 34 814 male subjects were included. Of them, 1035 subjects with lead exposure, 200 subjects with cadmium exposure and the 33 579 remaining were assigned to cohort A, cohort B and the control cohort, respectively. Data including personal history of alcohol and smoking, age, height, weight, the follow-up duration, haemoglobin A1c (HbA1c), fasting blood sugar (FBS), ferritin levels, and lead and cadmium levels within 1 year after exposure were collected.

PRIMARY OUTCOME MEASURE

In subjects without diabetes, changes in FBS and HbA1c were analysed through repeated tests at intervals of 1 year or longer after the occupational exposure to heavy metals.

RESULTS

In Cohort A, DM was diagnosed in 33 subjects. There was a significant difference in lead concentrations between the subjects diagnosed with DM and those without DM during the follow-up period (3.94±2.92 mg/dL vs 2.81±2.03 mg/dL, p=0.002). Simple exposure to heavy metals (lead and cadmium) was not associated with DM in Cox regression models (lead exposure (HR) 1.01, 95% CI: 0.58 to 1.77, p 0.971; cadmium exposure HR 1.48, 95% CI: 0.61 to 3.55, p=0.385). Annual changes in FBS according to lead concentration at the beginning of exposure showed a positive correlation (r=0.072, p=0.032).

CONCLUSION

Our findings demonstrated that simple occupational exposure to heavy metals lead and cadmium was not associated with the incidence of DM. However, lead concentrations at the beginning of the exposure might be an indicator of DM and glucose elevations.

Fish protein intake is a novel dietary approach for managing diabetes-associated complications in diabetic Wistar rat model

Diabetes mellitus is a metabolic disorder associated with short term as well as long-term undesirable complications caused by persistent hyperglycemia. Recently, there has been emerging evidence that natural foods and their bioactive compounds are the key contributors to the treatment of diabetes and associated complications. This study was designed to explore the therapeutic efficacy of a fish protein-rich diet for managing diabetes and associated complications in the diabetic Wistar rat model. A high-protein (HP) diet (45% and 55% fish protein rich in ω3 fatty acids) was given to alloxan-induced diabetic rats for 28 days. Blood samples were collected for monitoring serum glucose, oxidative stress markers, lipid profile, kidney function markers, serum proteins, and liver function markers. Results indicated that there was a noteworthy control (p < .05) of serum glucose, oxidative stress, and lipid profile in HP diet treated diabetic rats. Treatment with 45% and 55% fish diet appreciably improved the concentration of serum creatinine, urea, uric acid and exhibited a vibrant improvement in renal functions. Our results confirmed that the HP diet restored total protein and albumin concentration in blood. The HP diet treatment also restored the normal serum aspartate transaminase and alanine aminotransferase concentration.

The Role of Oxidative Stress in Cardiovascular Aging and Cardiovascular Diseases

Aging can be seen as process characterized by accumulation of oxidative stress induced damage. Oxidative stress derives from different endogenous and exogenous processes, all of which ultimately lead to progressive loss in tissue and organ structure and functions. The oxidative stress theory of aging expresses itself in age-related diseases. Aging is in fact a primary risk factor for many diseases and in particular for cardiovascular diseases and its derived morbidity and mortality. Here we highlight the role of oxidative stress in age-related cardiovascular aging and diseases. We take into consideration the molecular mechanisms, the structural and functional alterations, and the diseases accompanied to the cardiovascular aging process.

Oxidative Stress Product, 4-Hydroxy-2-Nonenal, Induces the Release of Tissue Factor-Positive Microvesicles From Perivascular Cells Into Circulation

OBJECTIVE

TF (Tissue factor) plays a key role in hemostasis, but an aberrant expression of TF leads to thrombosis. The objective of the present study is to investigate the effect of 4-hydroxy-2-nonenal (HNE), the most stable and major oxidant produced in various disease conditions, on the release of TF+ microvesicles into the circulation, identify the source of TF+ microvesicles origin, and assess their effect on intravascular coagulation and inflammation. Approach and Results: C57BL/6J mice were administered with HNE intraperitoneally, and the release of TF+ microvesicles into circulation was evaluated using coagulation assays and nanoparticle tracking analysis. Various cell-specific markers were used to identify the cellular source of TF+ microvesicles. Vascular permeability was analyzed by the extravasation of Evans blue dye or fluorescein dextran. HNE administration to mice markedly increased the levels of TF+ microvesicles and thrombin generation in the circulation. HNE administration also increased the number of neutrophils in the lungs and elevated the levels of inflammatory cytokines in plasma. Administration of an anti-TF antibody blocked not only HNE-induced thrombin generation but also HNE-induced inflammation. Confocal microscopy and immunoblotting studies showed that HNE does not induce TF expression either in vascular endothelium or circulating monocytes. Microvesicles harvested from HNE-administered mice stained positively with CD248 and α-smooth muscle actin, the markers that are specific to perivascular cells. HNE was found to destabilize endothelial cell barrier integrity.

CONCLUSIONS

HNE promotes the release of TF+ microvesicles from perivascular cells into the circulation. HNE-induced increased TF activity contributes to intravascular coagulation and inflammation.

Aerobic exercise training partially reverses the impairment of Nrf2 activation in older humans

Nuclear factor erythroid-2-related factor 2 (Nrf2), is an inducible transcription factor that improves redox balance through stimulating antioxidant gene expression. In older humans the Nrf2 response to a single bout of acute exercise is blunted compared to young indicating impaired redox signaling. The purpose of this randomized controlled trial was to investigate if the signaling impairment could be reversed with exercise training in older men and women, while also comparing to young. Young (18-28y, n = 21) and older (≥60y, n = 19) men and women were randomized to 8-week aerobic exercise training (ET; 3 d/wk, 45 min/d) or a non-exercise control group (CON). Nrf2 nuclear localization, gene expression for NQO1, HO1, and GCLC, and GCLC protein were measured in PBMCs in response to acute exercise trial (AET; 30-min cycling at 70% VO₂ peak pre- and post-intervention at 7 timepoints (Pre, +10 m, +30 m, +1 h, +4 h, +8 h, +24 h). Young had greater Nrf2 signaling response compared to older at pre-intervention (p = 0.05), whereas the older had significantly higher basal Nrf2 levels (p = 0.004). ET decreased basal Nrf2 expression compared to CON (p = 0.032) and improved the Nrf2 signaling response in both young and older (p < 0.05). The degree of restoration in Nrf2 signaling response was related to the degree of change in basal Nrf2 (p = 0.039), which was driven by older adults (p = 0.014). Lower basal nuclear Nrf2 levels were associated with changes seen in AET responses for Nrf2 and GCLC protein, as well as NQO1 and GCLC mRNA. Together these data demonstrate that exercise training improves Nrf2 signaling and downstream gene expression and that lower basal Nrf2 levels are associated with a more dynamic acute response. Our results provide evidence that the impaired Nrf2 signaling in sedentary older adults can be restored to a degree with moderate exercise training, albeit not to the level seen in young. CLINICALTRIALS.GOV ID: NCT03419988.

Polysaccharides from the Fleshy Fruits of Camellia oleifera Attenuate the Kidney Injury in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

The fleshy fruits of Camellia oleifera Abel are the immature fruits of C. oleifera, which are infected by Exobasidium vexans Massee and then turn to be intumescent and hollowed. They contain rich trace elements and vitamin C and are eaten directly as wild fruits in the Chinese countryside. Recent studies report that C. oleifera has anti-inflammatory and antioxidative effects. The current study, for the first time, evaluates the renal protective capacity of polysaccharides from the fleshy fruits of C. oleifera (CFFP) in streptozotocin-induced diabetic mice fed high-fat diets. The diabetic mice were orally administered CFFP for 3 months to evaluate the renoprotective function of CFFP. Our results indicated that 250 mg/kg CFFP significantly alleviated diabetes-induced renal injury by decreasing serum creatine, blood urea nitrogen levels, the kidney/body weight ratio, expression of fibronectin and collagen, as well as the secretion of tumor necrosis factor-α and interleukin-6. Additionally, 250 mg/kg CFFP could significantly ameliorate renal oxidative stress through increasing glutathione levels and lowering malondialdehyde contents. We confirmed that CFFP could exert antioxidative, anti-inflammatory, and antifibrosis activities. CFFP might be a potential therapeutic agent, and the fleshy fruits of C. oleifera might be a diet therapy for diabetic patients in the future.

AMPK allostery: A therapeutic target for the management/treatment of diabetic nephropathy

Diabetic nephropathy (DN) is a chronic complication of diabetes mellitus (DM) with approximately 30-40% of patients with DM developing nephropathy, and it is the leading cause of end-stage renal diseases and diabetic morbidity. The pathogenesis of DN is primarily associated with irregularities in the metabolism of glucose and lipid leading to hyperglycemia-induced oxidative stress, which has been a major target together with blood pressure regulation in the control of DN progression. However, the regulation of 5' adenosine monophosphate-activated protein kinase (AMPK), a highly conserved protein kinase for maintaining energy balance and cellular growth and repair has been implicated in the development of DM and its complications. Therefore, targeting AMPK pathway has been explored as a therapeutic strategy for the treatment of diabetes and its complication, although most of the mechanisms have not been fully elucidated. In this review, we discuss the structure of AMPK relevant to understanding its allosteric regulation and its role in the pathogenesis and progression of DN. We also identify therapeutic agents that modulate AMPK and its downstream targets with their specific mechanisms of action in the treatment of DN.

Astaxanthin Protects Retinal Photoreceptor Cells against High Glucose-Induced Oxidative Stress by Induction of Antioxidant Enzymes via the PI3K/Akt/Nrf2 Pathway

Diabetic retinopathy (DR) is a major microvascular complication that can lead to severe visual impairment in patients with diabetes. The elevated oxidative stress and increased reactive oxygen species (ROS) production induced by hyperglycemia have been reported to play an important role in the complex pathogenesis of DR. Astaxanthin (AST), a natural carotenoid derivative, has been recently recognized as a strong free radical scavenger and might, therefore, be beneficial in different diseases, including DR. In this study, we evaluated the potential role of AST as an antioxidative and antiapoptotic agent in protecting retinal cells and also investigated the involvement of the PI3K/Akt/Nrf2 pathway in AST-mediated effects. We treated high glucose-cultured mouse photoreceptor cells (661W) with different concentrations of AST and analyzed ROS production and cell apoptosis in the different regimens. Moreover, we also analyzed the expression of PI3K, Akt, Nrf2, and Phase II enzymes after AST treatment. Our results showed that AST dose-dependently reduced ROS production and attenuated 661W cell apoptosis in a high glucose environment. Importantly, its protective effect was abolished by treatment with PI3K or Nrf2 inhibitors, indicating the involvement of the PI3K/Akt/Nrf2 pathway. These results suggest AST as a nutritional supplement that could benefit patients with DR.

Small changes in glucose variability induced by low and high glycemic index diets are not associated with changes in β-cell function in adults with pre-diabetes

Oscillating glucose levels can increase oxidative stress and may contribute to β-cell dysfunction. We tested the hypothesis that increased glycemic variability contributes to β-cell dysfunction by experimentally altering glucose variability with controlled diets varying in glycemic index (GI). Fifty-two adults with prediabetes received a 2-week moderate GI (GI = 55-58) control diet followed by randomization to a four-week low GI (LGI: GI < 35) or high GI (HGI HI > 70) diet. Those on the HGI diet were randomized to placebo or the antioxidant N-acetylcysteine (NAC). Participants underwent blinded CGMS, fasting oxidative stress markers and an intravenous glucose tolerance test to estimate β-cell function (disposition index: DI). On the control diet, DI was inversely correlated with SD glucose (r = -0.314, p = 0.03), but neither DI nor glucose variability were associated with oxidative stress markers. The LGI diet decreased SD glucose (Control 0.96 ± 0.08 vs. LGI 0.79 ± 0.06, p = 0.02) while the HGI diet increased it (Control 0.88 ± 0.06 vs. HGI 1.06 ± 0.07, p = 0.03). Neither DI nor oxidative stress markers changed after the LGI or HGI diets. NAC had no effect on DI, glucose variability or oxidative stress markers. We conclude small changes in glucose variability induced by dietary GI in adults with pre-diabetes are unlikely to contribute to β-cell dysfunction.

Pharmacological and Advanced Cell Respiration Effects, Enhanced by Toxic Human-Bile Nano-Pharmaceuticals of Probucol Cell-Targeting Formulations

Bile acids have recently been studied for potential applications as formulation excipients and enhancers for drug release; however, some bile acids are not suitable for this application. Unconjugated lithocholic acid (ULCA) has recently shown drug formulation-stabilizing and anti-inflammatory effects. Lipophilic drugs have poor gut absorption after an oral dose, which necessitates the administration of high doses and causes subsequent side effects. Probucol (PB) is a highly lipophilic drug with poor oral absorption that resulted in restrictions on its clinical prescribing. Hence, this study aimed to design new delivery systems for PB using ULCA-based matrices and to test drug formulation, release, temperature, and biological effects. ULCA-based matrices were formulated for PB oral delivery by applying the jet-flow microencapsulation technique using sodium alginate as a polymer. ULCA addition to new PB matrices improved the microcapsule’s stability, drug release in vitro (formulation study), and showed a promising effect in ex vivo study (p < 0.05), suggesting that ULCA can optimize the oral delivery of PB and support its potential application in diabetes treatment.

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.

Effects of a Red Orange and Lemon Extract in Obese Diabetic Zucker Rats: Role of Nicotinamide Adenine Dinucleotide Phosphate Oxidase

Diabetic nephropathy (DN) is the primary cause of end-stage renal disease, worldwide, and oxidative stress has been recognized as a key factor in the pathogenesis and progression of DN. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase has the most important contribution to reactive oxygen species generation during the development of DN. Bioactive compound use has emerged as a potential approach to reduce chronic renal failure. Therefore, a red orange and lemon extract (RLE) rich in anthocyanins was chosen in our study, to reduce the toxic renal effects during the development of DN in Zucker diabetic fatty rat (ZDF). RLE effects were examined daily for 24 weeks, through gavage, in ZDF rats treated with RLE (90 mg/kg). At the end of the experiment, ZDF rats treated with RLE showed a reduction of the diabetes-associated up-regulation of both NOX4 and the p47-phox and p22-phox subunits, and restored the BAX/BCL-2 ratio respect to ZDF rats. Furthermore, RLE was able to reduce the oxidative DNA damage measured in urine samples in ZDF rats. This study showed that RLE could prevent the renal damage induced by DN through its capacity to inhibit NOX4 and apoptosis mechanisms.

Mendelian randomization study of serum uric acid levels and diabetes risk: evidence from the Dongfeng-Tongji cohort

OBJECTIVE

Limited Mendelian randomization (MR) studies have assessed the causal relationship between serum uric acid levels and diabetes risk. Here we investigated causality between the serum uric acid concentration and diabetes risk in Chinese population.

RESEARCH DESIGN AND METHODS

The observational analysis, based on the Dongfeng-Tongji prospective cohort (n=15 195) we tested the association of serum uric acid levels with incident diabetes risk. In the instrumental variable analysis, we examined the association of the genetic risk score (GRS) of serum uric acid with diabetes risk in case-control design (2539 cases and 4595 controls) via MR analysis.

RESULTS

During a mean (SD) follow-up of 4.5 (0.5) years, 1156 incident diabetes cases were identified. Compared with those in the lowest quintile of serum uric acid levels, the HRs of incident diabetes were 1.19 (95% CI 0.96 to 1.48), 1.12 (95% CI 0.90 to 1.40), 1.38 (95% CI 1.12 to 1.70), and 1.51 (95% CI 1.23 to 1.87) for Q2, Q3, Q4 and Q5, respectively (P-trend <0.001). The GRS was strongly associated with serum uric acid levels (β=0.17, 95% CI 0.15 to 0.19; P=2.81×10^-67). However, no significant association was observed between the GRS and diabetes risk (OR=1.01, 95 CI 0.95 to 1.06; P=0.75).

CONCLUSIONS

Even though serum uric acid levels were significantly associated with increased incident diabetes risk, the results did not provide evidence for a causal relationship between them.

Inhibition of HMGB1 Promotes Osseointegration under Hyperglycemic Condition through Improvement of BMSC Dysfunction

High mobility group box 1 (HMGB1) participates actively in oxidative stress damage and the latter relates closely to diabetic complications, including poor implant osseointegration. This article is aimed at investigating the effects of HMGB1 on dysfunction of bone marrow stromal cells (BMSCs) and impaired osseointegration under diabetic environment. In vitro, BMSCs were treated with normal glucose (NG), high glucose (HG), and HG+glycyrrhizin (HMGB1 inhibitor, HG+GL). Cell proliferation, osteogenic behaviors, and oxidative stress were determined. In vivo, 8-week-old Sprague-Dawley rats were categorized to control, streptozotocin-induced diabetic, and diabetic-GL groups. Rats received GL (50 mg/kg, i.p.) or vehicle treatment daily after titanium implants were planted into the tibiae. After 4 and 8 weeks, plasma lipoperoxide detection, μCT analysis, and histomorphometric evaluation were conducted. By these approaches, we demonstrated that inhibiting HMGB1 by GL significantly attenuated HG-induced upregulation of HMGB1, HMGB1 ligand receptor for advanced glycation end products (RAGE) and their interaction, relieved oxidative stress, and reversed the downregulation of osteogenic markers, resulting in improved osteogenic differentiation. In diabetic rats, GL administration suppressed the upregulation of HMGB1, attenuated the lipoperoxide, and ameliorated the impaired trabecular structure and osseointegration. Taken together, inhibiting HMGB1 can be an effective approach to relieve BMSC dysfunction and enhance osseointegration under diabetic environment.

miR-485 suppresses inflammation and proliferation of mesangial cells in an in vitro model of diabetic nephropathy by targeting NOX5

Diabetic nephropathy (DN) is among the common complications of diabetes and is a major cause of end-stage kidney disease. Emerging data indicate that renal inflammation is involved in DN progression and aggravation. Still, the exact cellular mechanisms remain unclear. Dysregulated expression of microRNAs (miRNAs) is associated with multiple diseases, including DN. The relationship between miRNAs and inflammation in DN is also unexplored. Here, we evaluated the role of miR-485 in mediating the response of human mesangial cells (HMCs) to a high glucose (HG) concentration, and the potential underlying mechanism. We found that miR-485 expression is significantly decreased in HG-stimulated HMCs. Overexpression of miR-485 suppressed HG-induced proliferation of HMCs. Lower production of proinflammatory cytokines (i.e., TNF-α, IL-1β, and IL-6) was observed in miR-485-overexpressing HMCs. Overexpression of miR-485 markedly suppressed the overexpression of extracellular-matrix proteins, e.g., collagen IV (Col IV) and fibronectin (FN), in HG-stimulated HMCs. Furthermore, miR-485 suppressed the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 5 (NOX5), restrained the HG-induced HMC proliferation, downregulated the expression of proinflammatory cytokines, and inhibited the production of extracellular-matrix proteins in HMCs. These results provide new insights into the involvement of the miR-485-NOX5 signaling pathway in DN progression.

Peroxiredoxin2 Deficiency Aggravates Aging-Induced Insulin Resistance and Declines Muscle Strength

This study examined the role of peroxiredoxin2 (Prx2) in aging-induced insulin resistance and reduction in skeletal muscle function in young (2-month-old) and old (24-month-old) Prx2 knockout (KO) and wild-type mice. Plasma insulin levels increased with aging in Prx2 KO mice but not in wild-type mice. Insulin sensitivity in the whole-body and skeletal muscle as assessed with the hyperinsulinemic-euglycemic clamp was lower in Prx2 KO mice than in wild-type mice in the old group but was not significantly different between the two genotypes in the young group. Insulin-induced activation of intracellular signaling molecules was also suppressed in old Prx2 KO mice compared to their wild-type littermates. Oxidative stress, inflammation, and p53 expression levels in skeletal muscle were higher in Prx2 KO mice than in wild-type mice in the old group but were not different between the two genotypes in the young group. p53 expression was negatively correlated with skeletal muscle insulin sensitivity in old mice. Skeletal muscle mass was similar between the two genotypes but grip strength was reduced in old Prx2 KO mice compared to old wild-type mice. These results suggest that Prx2 plays a protective role in aging-induced insulin resistance and declines in muscle strength by suppressing oxidative stress.

Altered inflammasome machinery as a key player in the perpetuation of Rett syndrome oxinflammation

Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene. RTT patients show multisystem disturbances associated with an oxinflammatory status. Inflammasomes are multi-protein complexes, responsible for host immune responses against pathogen infections and redox-related cellular stress. Assembly of NLRP3/ASC inflammasome triggers pro-caspase-1 activation, thus, resulting in IL-1β and IL-18 maturation. However, an aberrant activation of inflammasome system has been implicated in several human diseases. Our aim was to investigate the possible role of inflammasome in the chronic subclinical inflammatory condition typical of RTT, by analyzing this complex in basal and lipopolysaccharide (LPS)+ATP-stimulated primary fibroblasts, as well as in serum from RTT patients and healthy volunteers. RTT cells showed increased levels of nuclear p65 and ASC proteins, pro-IL-1β mRNA, and NLRP3/ASC interaction in basal condition, without any further response upon the LPS + ATP stimuli. Moreover, augmented levels of circulating ASC and IL-18 proteins were found in serum of RTT patients, which are likely able to amplify the inflammatory response. Taken together, our findings suggest that RTT patients exhibited a challenged inflammasome machinery at cellular and systemic level, which may contribute to the subclinical inflammatory state feedback observed in this pathology.

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RTT cell shows a constitutive NFκB activation.

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Aberrant activation of inflammasome system is evident in RTT.

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This new evidence can explain the demonstrated subclinical inflammation in RTT.

Peroxiredoxin 6 Confers Protection Against Nonalcoholic Fatty Liver Disease Through Maintaining Mitochondrial Function

Aims: Nonalcoholic fatty liver disease (NAFLD) is accompanied by excessive reactive oxygen species (ROS) production, which has been suggested in several studies to link with mitochondrial function. However, the mechanistic role of ROS-mediated regulation of mitochondrial function in NAFLD has not been elucidated. Since peroxiredoxin 6 (PRDX6) is the only member of the antioxidant PRDX family that translocates to damaged mitochondria, we investigated the PRDX6-mediated antisteatotic mechanism using genetically modified mice and cells. Results: PRDX6 mice were more protective to lipid accumulation, liver injury, and insulin resistance after a high-fat diet. Mechanistically, PRDX6 is required for induction of mitochondrial antioxidant action and beta-oxidation through maintaining mitochondrial integrity and subsequently prevents ROS-induced lipogenesis. Interestingly, oxidative stress-induced Notch signaling was suppressed in PRDX6 mice compared with wild-type mice, and genetic and pharmacological inhibition of Notch signaling improved lipid accumulation. Finally, PRDX knockdown or Notch inhibition reduced induction of mitophagy. PRDX6 antagonizes positive feedback loop between lipid accumulation and ROS production through regulation of mitochondrial function. Innovation: For the first time, we demonstrate that PRDX6 maintains mitochondria integrity under oxidative stress and protects against NAFLD progression by inhibition of Notch signaling. Conclusion: This study describes a novel molecular mechanism underlying the antisteatotic activity of PRDX6, which may be a new therapeutic strategy for the treatment of NAFLD.