Spontaneous NETosis in diabetes: A role of hyperglycemia mediated ROS and autophagy

Type 2-diabetes, particularly poorly controlled diabetes, is a risk factor for several infections such as lower respiratory tract and skin infections. Hyperglycemia, a characteristic downstream effect of poorly controlled diabetes, has been shown to impair the function of immune cells, in particular neutrophils. Several studies have demonstrated that hyperglycemia-mediated priming of NADPH oxidase results in subsequent elevated levels of reactive oxygen species (ROS). In healthy neutrophils, ROS plays an important role in pathogen killing by phagocytosis and by induction of Neutrophil Extracellular Traps (NETs). Given the key role of ROS in autophagy, phagocytosis and NETosis, the relationship between these pathways and the role of diabetes in the modulation of these pathways has not been explored previously. Therefore, our study aimed to understand the relationship between autophagy, phagocytosis and NETosis in diabetes. We hypothesized that hyperglycemia-associated oxidative stress alters the balance between phagocytosis and NETosis by modulating autophagy. Using whole blood samples from individuals with and without type 2-diabetes (in the presence and absence of hyperglycemia), we demonstrated that (i) hyperglycemia results in elevated levels of ROS in neutrophils from those with diabetes, (ii) elevated levels of ROS increase LCIII (a marker for autophagy) and downstream NETosis. (iii) Diabetes was also found to be associated with low levels of phagocytosis and phagocytic killing of S. pneumoniae. (iv) Blocking either NADPH oxidase or cellular pathways upstream of autophagy led to a significant reduction in NETosis. This study is the first to demonstrate the role of ROS in altering NETosis and phagocytosis by modulating autophagy in type 2-diabetes. GRAPHICAL ABSTRACT.

Ayurvedic Herbal Preparation Supplementation Does Not Improve Metabolic Health in Impaired Glucose Tolerance Subjects; Observations from a Randomised Placebo Controlled Trial

The increased usage of alternative Ayurvedic treatments as potential health-beneficial therapies emphasizes the importance of studying its efficacy in sound placebo-controlled intervention trials. An example of such a traditional Ayurvedic herbal preparation is Mohana Choorna, a mixture composed of 20 different herbs and used to prevent and treat type 2-diabetes (T2D). We studied the efficacy of “Mohana Choorna” on T2D-related parameters in subjects with impaired glucose tolerance. In a double blind, placebo-controlled cross-over trial, 19 overweight (BMI > 27 kg/m²) subjects aged 50–70 years with an impaired glucose tolerance received two four-week interventions, i.e., herbal or placebo with a four-week wash-out between interventions. HbA1c, glucose, insulin, triglycerides, cholesterol, blood pressure and augmentation index were measured before and after both interventions at fasting and during a glucose tolerance test. After both interventions, urine was collected to measure treatment exposure using LCMS-based metabolomics and whole genome gene-expression in adipose tissue of 13 subjects. The herbal intervention did not affect plasma glucose triglycerides, cholesterol, blood pressure or the augmentation index but showed a trend towards an increased insulin, HOMA-IR and postprandial insulin levels (p = 0.054, p = 0.056 and p = 0.095 respectively). An increase in expression of inflammation-related gene sets in adipose tissue was observed after the herbal intervention compared to placebo. Urine metabolomic analysis did not reveal a correlation of the presence of specific plant metabolites with “health markers”. Our findings suggest that there is no substantiating evidence to claim that four weeks’ use of the Ayurvedic herbal supplement Mohana Choorna beneficially affects glucose homeostasis.

Alpha-1-Antichymotrypsin: A Common Player for Type 2 Diabetes and Alzheimer's Disease

BACKGROUND

Numerous studies have shown a significant association between Type 2 Diabetes Mellitus (T2D) and Alzheimer's Disease (AD), two pathologies affecting millions of people worldwide. Chronic inflammation and oxidative stress are two conditions common to these diseases, also affecting the activity of the serpin Alpha-1-antichymotrypsin (ACT), but a possible common role for this serpin in T2D and AD remains unclear.

OBJECTIVE

To explore the possible regulatory networks linking ACT to T2D and AD.

MATERIALS AND METHODS

A bibliographic search was carried out in PubMed, Medline, Open-i, ScienceDirect, Scopus, and SpringerLink for data indicating or suggesting association among T2D, AD, and ACT. Searched terms like "alpha-1-antichymotrypsin", "type 2 diabetes", "Alzheimer's disease", "oxidative stress", "pro-inflammatory mediators" among others were used. Moreover, common therapeutic strategies between T2D and AD as well as the use of ACT as a therapeutic target for both diseases were included.

RESULTS

ACT has been linked with the development and maintenance of T2D and AD and studies suggest their participation through the activation of inflammatory pathways and oxidative stress, mechanisms also associated with both diseases. Likewise, evidences indicate that diverse therapeutic approaches are common to both diseases.

CONCLUSION

Inflammatory and oxidative stresses constitute a crossroad for T2D and AD, where ACT could play an important role. In-depth research on ACT involvement in these two dysfunctions could generate new therapeutic strategies for T2D and AD.

Accumulation of 8-hydroxydeoxyguanosine, L-arginine and Glucose Metabolites by Liver Tumor Cells Are the Important Characteristic Features of Metabolic Syndrome and Non-Alcoholic Steatohepatitis-Associated Hepatocarcinogenesis

To uncover mechanisms and explore novel biomarkers of obesity, type 2 diabetes (T2DM) and nonalcoholic steatohepatitis (NASH)-associated hepatocarcinogenesis, cellular and molecular alterations in the liver, and hepatocellular carcinomas (HCCs) were investigated in NASH model 60-week-old Tsumura, Suzuki, Obese Diabetic (TSOD) mice and NASH HCC patients. Markedly elevated lipid deposition, inflammation, fibrosis, and peroxisome proliferation in the liver, preneoplastic lesions, and HCCs of TSOD mice were accompanied by accumulation of polysaccharides in the cellular cytoplasm and nuclei and increase of oxidative DNA damage marker, 8-hydroxydeoxyguanosine (8-OHdG) formation in the liver and altered foci. Metabolomics of TSOD mice HCCs demonstrated significant elevation of the concentration of amino acid L-arginine, phosphocreatine, S-adenosylmethionine/S-adenosylhomocysteine ratio, adenylate, and guanylate energy charges in coordination with tremendous rise of glucose metabolites, mostly fructose 1,6-diphosphate. L-arginine accumulation in HCCs was associated with significant under-expression of arginase 1 (ARG1), suppression of the urea cycle, methionine and putrescine degradation pathways, activation of Ser and Thr kinase Akt AKT, phosphoinositide 3-kinase (PI3K), extracellular signal-regulated kinase 1/2 (ERK1/2) kinases, β-catenin, mammalian target of rapamycin (mTOR), and cell proliferation. Furthermore, clinicopathological analysis in 20 metabolic syndrome/NASH and 80 HCV-positive HCC patients demonstrated significant correlation of negative ARG1 expression with poor tumor differentiation, higher pathological stage, and significant decrease of survival in metabolic syndrome/NASH-associated HCC patients, thus indicating that ARG1 could become a potential marker for NASH HCC. From these results, formation of oxidative stress and 8-OHdG in the DNA and elevation of glucose metabolites and L-arginine due to ARG1 suppression in mice liver cells are the important characteristics of T2DM/NASH-associated hepatocarcinogenesis, which may take part in activating oxidative stress resistance, synthesis of phosphocreatine, cell signaling, methylation, and proliferation.

Vasculoprotection as a Convergent, Multi-Targeted Mechanism of Anti-AD Therapeutics and Interventions

Using a variety of animal models of Alzheimer's disease (AD), there have been a number of recent studies reporting varying degrees of success with anti-AD therapeutics. The efficacies are often discussed in terms of the modulatory effects of the compounds tested on identified or assumed targets among the known (or proposed) pathogenic and neuroprotective mechanisms, largely within the context of the dominant amyloid cascade hypothesis. However, it is clear that several of the relatively more efficacious treatments tend to be multifunctional and target multiple pathological processes associated with AD including most commonly, oxidative and metabolic stress and neuroinflammation. Increasing evidence suggests that vascular and neurodegenerative pathologies often co-exist and that neurovascular dysfunction plays a critical role in the development or progression of AD. In this review, we will discuss the significance of vasculoprotection or neurovascular unit integrity as a common, multi-targeted mechanism underlying the reported efficacy of a majority of anti-AD therapeutics--amyloid-targeted or otherwise--while providing a strong support for future neurovascular-based treatment strategies and interventions.