Protective effect of N-acetylcysteine supplementation on mitochondrial oxidative stress and mitochondrial enzymes in cerebral cortex of streptozotocin-treated diabetic rats

Phytochemical analysis, antioxidant activity and modulatory effect of aqueous leaf extract of Pistacia lentiscus L on oxaliplatin-induced oxidative stress in isolated rat liver mitochondria

This study evaluates the antioxidant effects of aqueous leaf extract of Pistacia lentiscus (ALEPL) and its potential to counteract oxaliplatin (OXA)-induced mitochondrial oxidative stress in rat livers, a common side effect of chemotherapy in cancer treatment. Bioactive compounds were identified using High-Performance Liquid Chromatography coupled with Tandem Mass Spectrometry (HPLC-MS and MS), with Fourier-Transform Infrared Spectroscopy (FTIR) and Atomic Absorption Spectrophotometry (AAS) for chemical and mineral analysis. ALEPL showed notable antioxidant activity, with IC50 values of 4.30 ± 0.27 μg/mL for DPPH (2,2-Diphenyl-1-picrylhydrazyl) scavenging, 13.64 ± 0.51 μg/mL for reducing power, 32.62 ± 5.32 μg/mL for hydroxyl radical scavenging, and 205.08 ± 25.77 μg/mL for superoxide anion radical scavenging. In ex vivo experiments, mitochondria isolated from Wistar rat livers were treated with OXA and ALEPL in a dose-dependent manner. ALEPL pretreatment effectively restored mitochondrial antioxidant enzyme activities, increased glutathione (GSH) levels, and reduced lipid peroxidation (MDA) caused by OXA. These findings suggest that ALEPL has the potential to act as a natural antioxidant to support cancer treatment by mitigating chemotherapy-induced oxidative stress. Future studies could explore its application as an adjuvant in clinical settings to enhance the efficacy of chemotherapy while reducing its side effects.

Association Between Type 2 Diabetes Mellitus and Alzheimer's Disease: Common Molecular Mechanism and Therapeutic Targets

Diabetes mellitus (DM) and Alzheimer's disease (AD) rates are rising, mirroring the global trend of an aging population. Numerous epidemiological studies have shown that those with Type 2 diabetes (T2DM) have an increased risk of developing dementia. These degenerative and progressive diseases share some risk factors. To a large extent, the amyloid cascade is responsible for AD development. Neurofibrillary tangles induce neurodegeneration and brain atrophy; this chain reaction begins with hyperphosphorylation of tau proteins caused by progressive amyloid beta (Aβ) accumulation. In addition to these processes, it seems that alterations in brain glucose metabolism and insulin signalling lead to cell death and reduced synaptic plasticity in AD, before the onset of symptoms, which may be years away. Due to the substantial evidence linking insulin resistance in the brain with AD, researchers have coined the name "Type 3 diabetes" to characterize the condition. We still know little about the processes involved, even though current animal models have helped illuminate the links between T2DM and AD. This brief overview discusses insulin and IGF-1 signalling disorders and the primary molecular pathways that may connect them. The presence of GSK-3β in AD is intriguing. These proteins' association with T2DM and pancreatic β-cell failure suggests they might be therapeutic targets for both disorders.

True or false? Alzheimer's disease is type 3 diabetes: Evidences from bench to bedside

Globally, Alzheimer's disease (AD) is the most widespread chronic neurodegenerative disorder, leading to cognitive impairment, such as aphasia and agnosia, as well as mental symptoms, like behavioral abnormalities, that place a heavy psychological and financial burden on the families of the afflicted. Unfortunately, no particular medications exist to treat AD, as the current treatments only impede its progression.The link between AD and type 2 diabetes (T2D) has been increasingly revealed by research; the danger of developing both AD and T2D rises exponentially with age, with T2D being especially prone to AD. This has propelled researchers to investigate the mechanism(s) underlying this connection. A critical review of the relationship between insulin resistance, Aβ, oxidative stress, mitochondrial hypothesis, abnormal phosphorylation of Tau protein, inflammatory response, high blood glucose levels, neurotransmitters and signaling pathways, vascular issues in AD and diabetes, and the similarities between the two diseases, is presented in this review. Grasping the essential mechanisms behind this detrimental interaction may offer chances to devise successful therapeutic strategies.

Restoring energy metabolism by NAD+ supplement prevents alcohol-induced liver injury and boosts liver regeneration

Our previous clinical metabolomics study illustrated that energy metabolism disorder is an underlying pathogenesis mechanism for the development of alcoholic liver disease (ALD). Supplementation of nicotinamide (NAM), the precursor of nicotinamide adenine dinucleotide (NAD+), may restore the energy metabolism homeostasis of ALD and thus serves as potential therapeutics to treat ALD. In this bedside-to-bench study, the protective effect of NAM against ALD was investigated by using the NIAAA mice model (chronic-plus-binge ethanol), and the liver regeneration boosting capability of NAM was evaluated by the partial hepatectomy mice model. Our results showed that NAM supplements not only protected the liver from alcohol-induced injury and improved alcohol-induced mitochondrial structure and function change, but also boosted liver regeneration in postpartial hepatectomy mice by increasing liver NAD+ content. These findings suggested that NAM, a water-soluble form of vitamin B3, can promote liver regeneration and improves liver function by alleviating alcohol-induced energy metabolism disorder.

Platycodin D Ameliorates Cognitive Impairment in Type 2 Diabetes Mellitus Mice via Regulating PI3K/Akt/GSK3β Signaling Pathway

Objectives: The aim of this study was to investigate the ameliorative effect of platycodin D (PD) on cognitive dysfunction in type 2 diabetes mellitus (T2DM) and its potential molecular mechanisms of action in vivo and in vitro. Materials and methods: An animal model of cognitive impairment in T2DM was established using a single intraperitoneal injection of streptozotocin (100 mg/kg) after 8 weeks of feeding a high-fat diet to C57BL/6 mice. In vitro, immunofluorescence staining and Western blot were employed to analyze the effects of PD on glucose-induced neurotoxicity in mouse hippocampal neuronal cells (HT22). Results: PD (2.5 mg/kg) treatment for 4 weeks significantly suppressed the rise in fasting blood glucose in T2DM mice, improved insulin secretion deficiency, and reversed abnormalities in serum triglyceride, cholesterol, low-density lipoprotein, and high-density lipoprotein levels. Meanwhile, PD ameliorated choline dysfunction in T2DM mice and inhibited the production of oxidative stress and apoptosis-related proteins of the caspase family. Notably, PD dose-dependently prevents the loss of mitochondrial membrane potential, promotes phosphorylation of phosphatidylinositol 3 kinase and protein kinase B (Akt) in vitro, activates glycogen synthase kinase 3β (GSK3β) expression at the Ser9 site, and inhibits Tau protein hyperphosphorylation. Conclusions: These findings clearly indicated that PD could alleviate the neurological damage caused by T2DM, and the phosphorylation of Akt at Ser473 may be the key to its effect.

Diabetes and Stroke: Impact of Novel Therapies for the Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a significant risk factor for stroke. Nevertheless, the evidence supporting stringent glycemic control to reduce macrovascular complications, particularly stroke, is not as clear as for microvascular complications. Presently, risk reduction strategies are based on controlling multiple risk factors, including hypertension, dyslipidemia, glycemia, smoking, and weight. Since 2008, new pharmacological therapies for treating T2DM have been required to undergo trials to ensure their cardiovascular safety. Remarkably, several novel therapies have exhibited protective effects against the combined endpoint of major cardiovascular events. Evidence from these trials, with stroke as a secondary endpoint, along with real-world data, suggests potential benefits in stroke prevention, particularly with glucagon-like peptide 1 receptor agonists. Conversely, the data on sodium-glucose cotransporter type 2 inhibitors remains more controversial. Dipeptidyl peptidase 4 inhibitors appear neutral in stroke prevention. More recent pharmacological therapies still lack significant data on this particular outcome. This article provides a comprehensive review of the evidence on the most recent T2DM therapies for stroke prevention and their impact on clinical practice.

Exposure to fluoride exacerbates the cognitive deficit of diabetic patients living in areas with endemic fluorosis, as well as of rats with type 2 diabetes induced by streptozotocin via a mechanism that may involve excessive activation of the poly(ADP ribose) polymerase-1/P53 pathway

Epidemiology has shown that fluoride exposure is associated with the occurrence of diabetes. However, whether fluoride affects diabetic encephalopathy is unclear. Elderly diabetic patients in areas with endemic (n = 169) or no fluorosis (108) and controls (85) underwent Montreal Cognitive Assessment. Sprague-Dawley rats receiving streptozotocin and/or different fluoride doses were examined for spatial learning and memory, brain morphology, blood-brain barrier, fasting blood glucose and insulin. Cultured SH-SY5Y cells were treated with 50 mM glucose and/or low- or high-dose fluoride, and P53-knockdown or poly-ADP-ribose polymerase-1 (PARP-1) inhibition. The levels of PARP-1, P53, poly-ADP-ribose (PAR), apoptosis-inducing factor (AIF), and phosphorylated-histone H2A.X (ser139) were measured by Western blotting. Reactive oxygen species (ROS), 8-hydroxydeguanosine (8-OHdG), PARP-1 activity, acetyl-P53, nicotinamide adenine dinucleotide (NAD+), activities of mitochondrial hexokinase1 (HK1) and citrate synthase (CS), mitochondrial membrane potential and apoptosis were assessed biochemically. Cognition of diabetic patients in endemic fluorosis areas was poorer than in other regions. In diabetic rats, fasting blood glucose, insulin resistance and blood-brain barrier permeability were elevated, while spatial learning and memory and Nissl body numbers in neurons declined. In these animals, expression and activity of P53 and PARP-1 and levels of NAD+, PAR, ROS, 8-OHdG, p-histone H2A.X (ser139), AIF and apoptosis content increased; whereas mitochondrial HK1 and CS activities and membrane potential decreased. SH-SY5Y cells exposed to glucose exhibited changes identical to diabetic rats. The changes in diabetic rats and cells treated with glucose were aggravated by fluoride. P53-knockout or PARP-1 inhibition mitigated the effects of glucose with/without low-dose fluoride. Elevation of diabetic encephalopathy was induced by exposure to fluoride and the underlying mechanism may involve overactivation of the PARP-1/P53 pathway.

Profiling the antidiabetic potential of GC-MS compounds identified from the methanolic extract of Spilanthes filicaulis: experimental and computational insight

This study examines the nutritional composition, phytochemical profiling, and antioxidant, antidiabetic, and anti-inflammatory potential of a methanolic extract of Spilanthes filicaulis leaves (MESFL) via in vitro, ex vivo, and in silico studies. In vitro antioxidant, antidiabetic, and anti-inflammatory activities were examined. In the ex vivo study, liver tissues were subjected to FeSO4-induced oxidative damage and treated with varying concentrations of MESFL. MESFL contains a reasonable amount of nitrogen-free extract, moisture, ash content, crude protein, and fat, with a lesser amount of crude fiber. According to GC-MS analysis, MESFL contains ten compounds, the most abundant of which are 13-octadecenal and Ar-tumerone. In this study, MESFL demonstrated anti-inflammatory activities via membrane stabilizing properties, proteinase inhibition, and inhibition of protein denaturation (IC50 = 72.75 ± 11.06 µg/mL). MESFL also strongly inhibited both α-amylase (IC50 = 307.02 ± 4.25 µg/mL) and α-glucosidase (IC50 = 215.51 ± 0.47 µg/mL) activities. Our findings also showed that FeSO4-induced tissue damage decreased the levels of GSH, SOD, and CAT activities while increasing the levels of MDA. In contrast, treatment with MESFL helped to restore these parameters to near-normal levels, which signifies that MESFL has great potential to address complications from oxidative stress. Furthermore, the in silico interaction of the GCMS-identified phytochemicals with the active sites of α-amylase and α-glucosidase via molecular and ensembled-based docking displayed strong binding affinities of Ar-tumerone and 4-hydroxy-3-methylacetophenone to α-amylase and α-glucosidase, respectively. Taken together, the biological activities of MESFL might be a result of the effects of these secondary metabolites.Communicated by Ramaswamy H. Sarma.

Hydrogen sulfide: From a toxic gas to a potential therapy for COVID-19 and inflammatory disorders

COVID-19 has been shown to induce inflammatory disorders and CNS manifestations. Swift and efficient treatment strategies are urgently warranted for the management of COVID, inflammatory and neurological disorders. Hydrogen sulfide (H2S) has been associated with several clinical disorders due to its potential to influence a broad range of biological signalling pathways. According to recent clinical studies, COVID patients with lower physiological H2S had higher fatality rates. These findings clearly demonstrate an inverse correlation between H2S levels and the severity of COVID-19. H2S has been proposed as a protective molecule because of its antioxidant, anti-inflammatory, and antiviral properties. Various H2S-releasing prodrugs, hybrids and natural compounds have been tested for their therapeutic efficacy in viral infections and inflammatory disorders. In this review, I am highlighting the rationale for using H2S-based interventions for the management of COVID-19 and post-infection inflammatory disorders including neuroinflammation. I am also proposing therepurposing of existing H2S-releasing prodrugs, developing new NO-H2S-hybrids, targeting H2S metabolic pathways, and using H2S-producing dietary supplements as viable defensive strategies against SARS-CoV-2 infection and COVID-19 pathologies.

Gut microbiota interacts with inflammatory responses in acute pancreatitis

Acute pancreatitis (AP) is one of the most common acute abdominal conditions, and its incidence has been increasing for years. Approximately 15-20% of patients develop severe AP (SAP), which is complicated by critical inflammatory injury and intestinal dysfunction. AP-associated inflammation can lead to the gut barrier and function damage, causing dysbacteriosis and facilitating intestinal microbiota migration. Pancreatic exocrine deficiency and decreased levels of antimicrobial peptides in AP can also lead to abnormal growth of intestinal bacteria. Meanwhile, intestinal microbiota migration influences the pancreatic microenvironment and affects the severity of AP, which, in turn, exacerbates the systemic inflammatory response. Thus, the interaction between the gut microbiota (GM) and the inflammatory response may be a key pathogenic feature of SAP. Treating either of these factors or breaking their interaction may offer some benefits for SAP treatment. In this review, we discuss the mechanisms of interaction of the GM and inflammation in AP and factors that can deteriorate or even cure both, including some traditional Chinese medicine treatments, to provide new methods for studying AP pathogenesis and developing therapies.

Secondary Metabolite Profiling, Antioxidant, Antidiabetic and Neuroprotective Activity of Cestrum nocturnum (Night Scented-Jasmine): Use of In Vitro and In Silico Approach in Determining the Potential Bioactive Compound

This study aims to describe the therapeutic potential of C. nocturnum leaf extracts against diabetes and neurological disorders via the targeting of α-amylase and acetylcholinesterase (AChE) activities, followed by computational molecular docking studies to establish a strong rationale behind the α-amylase and AChE inhibitory potential of C. nocturnum leaves-derived secondary metabolites. In our study, the antioxidant activity of the sequentially extracted C. nocturnum leaves extract was also investigated, in which the methanolic fraction exhibited the strongest antioxidant potential against DPPH (IC₅₀ 39.12 ± 0.53 µg/mL) and ABTS (IC₅₀ 20.94 ± 0.82 µg/mL) radicals. This extract strongly inhibited the α-amylase (IC₅₀188.77 ± 1.67 µg/mL) and AChE (IC₅₀ 239.44 ± 0.93 µg/mL) in a non-competitive and competitive manner, respectively. Furthermore, in silico analysis of compounds identified in the methanolic extract of the leaves of C. nocturnum using GC-MS revealed high-affinity binding of these compounds with the catalytic sites of α-amylase and AChE, with binding energy ranging from -3.10 to -6.23 kcal/mol and from -3.32 to -8.76 kcal/mol, respectively. Conclusively, the antioxidant, antidiabetic, and anti-Alzheimer activity of this extract might be driven by the synergistic effect of these bioactive phytoconstituents.

The Impact of Pancreatic Exocrine Diseases on the β-Cell and Glucose Metabolism-A Review with Currently Available Evidence

Pancreatic exocrine and endocrine dysfunctions often come together in the course of pancreatic diseases as interdependent manifestations of the same organ. However, the mechanisms underlying the bidirectional connection of the exocrine and endocrine pancreas are not fully understood. In this review, we aimed to synthetize the current knowledge regarding the effects of several exocrine pancreatic pathologies on the homeostasis of β-cells, with a special interest in the predisposition toward diabetes mellitus (DM). We focused on the following pancreatic exocrine diseases: chronic pancreatitis, acute pancreatitis, cystic fibrosis, pancreatic cancer, pancreatic resections, and autoimmune pancreatitis. We discuss the pathophysiologic mechanisms behind the impact on β-cell function and evolution into DM, as well as the associated risk factors in progression to DM, and we describe the most relevant and statistically significant findings in the literature. An early and correct diagnosis of DM in the setting of pancreatic exocrine disorders is of paramount importance for anticipating the disease's course and its therapeutical needs.

Modulatory Role of Quercetin in Mitochondrial Dysfunction in Titanium Dioxide Nanoparticle-Induced Hepatotoxicity

Background : Titanium dioxide (TiO₂) nanoparticles are among the largely manmade nanomaterials worldwide and are broadly used as both industrial and user products. The primary target site for several nanoparticles is the liver, including TiO₂ nanoparticles (TNPs), exposed directly or indirectly through ingestion of contaminated water, food, or animals and elevated environmental contamination. Oxidative stress is a known facet of nanoparticle-induced toxicity, including TNPs. Mitochondria are potential targets for nanoparticles in several types of toxicity, such as hepatotoxicity. Nevertheless, its causal mechanism is still controversial due to scarcity of literature linking the role of mitochondria-mediated TNP-induced hepatotoxicity. Aim : The objective of the current study was to evaluate the relation of mitochondrial oxidative stress and respiratory chain mechanisms with TNP-induced mitochondrial dysfunction in vitro, and explore the hepatoprotective effect of quercetin (QR), which is a polyphenolic flavonoid abundant in fruits and vegetables with known antioxidant properties, on TNP-induced mitochondrial oxidative stress and disturbance in respiratory chain complex enzymes in the liver of rats. Results: Enzymatic and non-enzymatic antioxidant levels, oxidative stress markers, and mitochondrial complexes were assessed with regard to TNP-induced hepatotoxicity. The depleted lipid peroxidation levels and protein carbonyl content, in mitochondria, induced by TNPs were restored significantly by pretreatment with QR. QR modulated the altered non-enzymatic and enzymatic antioxidants and mitochondrial complex enzymes. Conclusion : Based on the findings, we conclude that QR, which mitigates oxidative stress caused by mitochondrial dysfunction, holds promising capability to potentially diminish TNP-induced adverse effects in the liver.

Toward the Decipherment of Molecular Interactions in the Diabetic Brain

Diabetes mellitus (DM) has been associated with cognitive complications in the brain resulting from acute and chronic metabolic disturbances happening peripherally and centrally. Numerous studies have reported on the morphological, electrophysiological, biochemical, and cognitive changes in the brains of diabetic individuals. The detailed pathophysiological mechanisms implicated in the development of the diabetic cognitive phenotype remain unclear due to intricate molecular changes evolving over time and space. This review provides an insight into recent advances in understanding molecular events in the diabetic brain, focusing on cerebral glucose and insulin uptake, insulin action in the brain, and the role of the brain in the regulation of glucose homeostasis. Fully competent mitochondria are essential for energy metabolism and proper brain function; hence, the potential contribution of mitochondria to the DM-induced impairment of the brain is also discussed.

Astaxanthin-s-allyl cysteine diester against high glucose-induced neuronal toxicity in vitro and diabetes-associated cognitive decline in vivo: Effect on p53, oxidative stress and mitochondrial function

Neuroprotective effect of astaxanthin-s-allyl cysteine diester (AST-SAC) against high glucose (HG)-induced oxidative stress in in vitro and cognitive decline under diabetes conditions in in vivo has been explored. Pretreatment of AST-SAC (5, 10 and 15 μM) dose-dependently preserved the neuronal cells (SH-SY5Y) viability against HG toxicity through i) decreasing oxidative stress (decreasing reactive oxygen species generation and increasing endogenous antioxidants level); ii) protecting mitochondrial function [oxidative phosphorylation (OXPHOS) complexes activity and mitochondrial membrane potential (MMP)]; and iii) decreasing p53 level thereby subsequently decreasing the level of apoptotic marker proteins. Male Spraque-Dawley rats were orally administered AST-SAC (1 mg/kg/day) for 45 days in streptozotocin-induced diabetes mellitus (DM) rats. AST-SAC administration prevented the loss of spatial memory in DM rats as determined using the novel object location test. AST-SAC administration alleviated the DM-induced injury in brain such as increased cholinesterases activity, elevated oxidative stress and mitochondrial dysfunction. Altogether, the results from the present study demonstrated that AST-SAC averted the neuronal apoptosis and preserved the cognitive function against HG toxicity under DM conditions.

LncRNA MEG3 Alleviates Diabetic Cognitive Impairments by Reducing Mitochondrial-Derived Apoptosis through Promotion of FUNDC1-Related Mitophagy via Rac1-ROS Axis

Mitochondrial dysfunction and elevated ROS generation are predominant contributors of neuronal death that is responsible for the diabetes-related cognitive impairments. Emerging evidence has demonstrated that long noncoding RNA-MEG3 can serve as an important regulator in the pathogenesis of diabetes. However, the underlying mechanisms remain to be further clarified. Here, it was observed that MEG3 was significantly down-regulated in STZ (streptozotocin)-induced diabetic rats. MEG3 overexpression noticeably improved diabetes-induced cognitive dysfunctions, accompanied by the abatement of Rac1 activation and ROS production, as well as the inhibition of mitochondria-associated apoptosis. Furthermore, either MEG3 overexpression or Rac1 inhibition promoted FUNDC1 dephosphorylation and suppressed oxidative stress and neuro-inflammation. Similarly, in vitro studies confirmed that hyperglycemia also down-regulated MEG3 expression in PC12 cells. MEG3 reintroduction protected PC12 cells against hyperglycemia-triggered neurotoxicity by improving mitochondrial fitness and repressing mitochondria-mediated apoptosis. Moreover, these neuroprotective effects of MEG3 relied on FUNDC1-related mitophagy, since silencing of FUNDC1 abolished these beneficial outcomes. Additionally, MEG3 rescued HG-induced neurotoxicity was involved in inhibiting Rac1 expression via interaction with Rac1 3'UTR. Conversely, knockdown of MEG3 showed opposite effects. NSC23766, a specific inhibitor of Rac1, fully abolished harmful effects of MEG3 depletion. Consistently, knockdown of Rac1 potentiated FUNDC1-associated mitophagy. Meanwhile, colocalization of Rac1 and FUNDC1 was found in mitochondria under hyperglycemia, which was interrupted by MEG3 overexpression. Furthermore, silencing of Rac1 promoted PGAM5 expression, and FUNDC1 strongly interacted with LC3 in Rac1-deleted cells. Altogether, our findings suggested that the Rac1/ROS axis may be a downstream signaling pathway for MEG3-induced neuroprotection, which was involved in FUNDC1-associated mitophagy.

Spatially Resolved Metabolomics Based on Air-Flow-Assisted Desorption Electrospray Ionization-Mass Spectrometry Imaging Reveals Region-Specific Metabolic Alterations in Diabetic Encephalopathy

Spatially resolved metabolic profiling of brain is vital for elucidating tissue-specific molecular histology and pathology underlying diabetic encephalopathy (DE). In this study, a spatially resolved metabolomic method based on air-flow-assisted desorption electrospray ionization-mass spectrometry imaging (AFADESI-MSI) was developed for investigating the region-specific metabolic disturbances in the brain of DE model rats induced by a high-fat diet in combination with streptozotocin administration. A total of 19 discriminating metabolites associated with glycolysis and the pentose phosphate pathway (PPP); the glutamate/gamma aminobutyric acid-glutamine cycle and tricarboxylic acid cycle; nucleotide metabolism; lipid metabolism; carnitine homeostasis; and taurine, ascorbic acid, histidine, and choline metabolism were identified and located in the brains of the diabetic rats simultaneously for the first time. The results indicated that increased glycolytic and PPP activity; dysfunction of mitochondrial metabolism; dysregulation of adenosinergic, glutamatergic, dopaminergic, cholinergic, and histaminergic systems; disorder of osmotic regulation and antioxidant system; and disorder of lipid metabolism occur in a region-specific fashion in the brains of DE rats. Thus, this study provides valuable information regarding the molecular pathological signature of DE. These findings also underline the high potential of AFADESI-MSI for applications in various central nervous system diseases.

Insulin actions on hypothalamic glucose-sensing neurones

Subsequent to the discovery of insulin 100 years ago, great strides have been made in understanding its function, especially in the brain. It is now clear that insulin is a critical regulator of the neuronal circuitry controlling energy balance and glucose homeostasis. This review focuses on the effects of insulin and diabetes on the activity and glucose sensitivity of hypothalamic glucose-sensing neurones. We highlight the role of electrophysiological data in understanding how insulin regulates glucose-sensing neurones. A brief introduction describing the benefits and limitations of the major electrophysiological techniques used to investigate glucose-sensing neurones is provided. The mechanisms by which hypothalamic neurones sense glucose are discussed with an emphasis on those glucose-sensing neurones already shown to be modulated by insulin. Next, the literature pertaining to how insulin alters the activity and glucose sensitivity of these hypothalamic glucose-sensing neurones is described. In addition, the effects of impaired insulin signalling during diabetes and the ramifications of insulin-induced hypoglycaemia on hypothalamic glucose-sensing neurones are covered. To the extent that it is known, we present hypotheses concerning the mechanisms underlying the effects of these insulin-related pathologies. To conclude, electrophysiological data from the hippocampus are evaluated aiming to provide clues regarding how insulin might influence neuronal plasticity in glucose-sensing neurones. Although much has been accomplished subsequent to the discovery of insulin, the work described in our review suggests that the regulation of central glucose sensing by this hormone is both important and understudied.

Diabetes-Alzheimer's Disease Link: Targeting Mitochondrial Dysfunction and Redox Imbalance

Significance: It is of common sense that the world population is aging and life expectancy is increasing. However, as the population ages, there is also an exponential risk to live into the ages where the brain-related frailties and neurodegenerative diseases develop. Hand in hand with those events, the world is witnessing a major upsurge in diabetes diagnostics. Remarkably, all of this seems to be narrowly related, and clinical and research communities highlight for the upcoming threat that it will represent for the present and future generations. Recent Advances: It is of utmost importance to clarify the influence of diabetes-related metabolic features on brain health and the mechanisms underlying the increased likelihood of developing neurodegenerative diseases, in particular Alzheimer's disease. Thereupon, a wealth of evidence suggests that mitochondria and associated oxidative stress are at the root of the link between diabetes and co-occurring disorders in the brain. Critical Issues: The scientific community has been challenged with constant failures of clinical trials raising major issues in the advance of the therapeutic field to fight chronic diseases epidemics. Thus, a change of paradigms is urgently needed. Future Directions: It has become urgent to identify new and solid candidates able to clinically reproduce the positive outcomes obtained in preclinical studies. On this basis, strategies settled to counteract diabetes-induced neurodegeneration encompassing mitochondrial dysfunction, redox status imbalance, and/or insulin dysregulation seem worth to follow. Hopefully, ongoing innovative research based on reliable experimental tools will soon bring the desired answers allowing pharmaceutical industry to apply such knowledge to human medicine.

Pathology, Risk Factors, and Oxidative Damage Related to Type 2 Diabetes-Mediated Alzheimer's Disease and the Rescuing Effects of the Potent Antioxidant Anthocyanin

The pathology and neurodegeneration in type 2 diabetes- (T2D-) mediated Alzheimer's disease (AD) have been reported in several studies. Despite the lack of information regarding the basic underlying mechanisms involved in the development of T2D-mediated AD, some common features of the two conditions have been reported, such as brain atrophy, reduced cerebral glucose metabolism, and insulin resistance. T2D phenotypes such as glucose dyshomeostasis, insulin resistance, impaired insulin signaling, and systemic inflammatory cytokines have been shown to be involved in the progression of AD pathology by increasing amyloid-beta accumulation, tau hyperphosphorylation, and overall neuroinflammation. Similarly, oxidative stress, mitochondrial dysfunction, and the generation of advanced glycation end products (AGEs) and their receptor (RAGE) as a result of chronic hyperglycemia may serve as critical links between diabetes and AD. The natural dietary polyflavonoid anthocyanin enhances insulin sensitivity, attenuates insulin resistance at the level of the target tissues, inhibits free fatty acid oxidation, and abrogates the release of peripheral inflammatory cytokines in obese (prediabetic) individuals, which are responsible for insulin resistance, systemic hyperglycemia, systemic inflammation, brain metabolism dyshomeostasis, amyloid-beta accumulation, and neuroinflammatory responses. In this review, we have shown that obesity may induce T2D-mediated AD and assessed the recent therapeutic advances, especially the use of anthocyanin, against T2D-mediated AD pathology. Taken together, the findings of current studies may help elucidate a new approach for the prevention and treatment of T2D-mediated AD by using the polyflavonoid anthocyanin.

Investigation of Proteus vulgaris and Elizabethkingia meningoseptica invasion on muscle oxidative stress and autophagy in Chinese soft-shelled turtle (Pelodiscus sinensis)

Muscle is an important structural tissue in aquatic animals and it is susceptible to bacterial and fungal infection, which could affect flesh quality and health. In this study, Chinese soft-shelled turtles were artificially infected with two pathogens, Proteus vulgaris and Elizabethkingia meningoseptica and the effects on muscle nutritional characteristics, oxidative stress and autophagy were assayed. Upon infection, the muscle nutritional composition and muscle fiber structure were notably influenced. Meanwhile, the mRNA expression of Nrf2 was down-regulated and Keap1 up-regulated, thus resulting in a decrease in antioxidant capacity and oxidative stress. However, with N-acetylcysteine treatment, the level of oxidative stress was decreased, accompanied by significant increases in antioxidant enzyme activities and the mRNA levels of SOD, CAT, GSTCD, and GSTO1. Interestingly, there was a significant increase in autophagy in the muscle tissue after the pathogen infection, but this increase could be reduced by N-acetylcysteine treatment. Our findings suggest that muscle nutritional characteristics were dramatically changed after pathogen infection, and oxidative stress and autophagy were induced by pathogen infection. However, N-acetylcysteine treatment could compromise the process perhaps by decreasing the ROS level and regulating Nrf2-antioxidant signaling pathways.

Neuroprotective effect of paeonol in streptozotocin-induced diabetes in rats

BACKGROUND

Diabetic neuropathy is one of the most common microvascular complication of diabetes. It is associated with neuronal dysfunction and pain. Paeonol is an important natural product reported for its antioxidant, anti-inflammatory and antidiabetic activities.

AIM

The present research was planned to study effect of paeonol in diabetic peripheral neuropathy in rats.

METHODS

Diabetes was induced in Sprague Dawley rats by using Streptozotocin (55 mg/kg, i.p.). After six weeks, diabetic animals were treated daily with paeonol at a dose of 50, 100 and 200 mg/kg for four weeks. At the end of the treatment, plasma glucose, mechanical allodynia, mechanical hyperalgesia, thermal hyperalgesia and nerve conduction velocities were recorded. Oxidative stress parameters were studied in sciatic nerve. Histopathology study of sciatic nerve, NF-κB and MCP-1 expression were also studied at the end of study.

KEY FINDINGS

Paeonol treatment significantly lowered the plasma glucose levels, mechanical allodynia, mechanical hyperalgesia and thermal hyperalgesia as compared to diabetic control group. Paeonol treatment also enhanced the motor and sensory nerve conduction velocity. Paeonol treated diabetic animals showed significant changes in oxidative stress parameters. Histopathology study indicated that paeonol treatment prevented the neuronal damage, lowered demyelination and leukocyte infiltration. NF-κB and MCP-1 expression was significantly decreased in sciatic nerve of diabetic animals treated with paeonol.

SIGNIFICANCE

Results of the present study indicate that paeonol may be considered as effective option for management of diabetic neuropathy.

Metabolic syndrome components and acute pancreatitis: a case-control study in China

Background

Acute pancreatitis (AP) is a common inflammatory disorder of the pancreas. Recent evidence has shown that metabolic syndrome is positively correlated with the severity of AP. However, only a few studies have revealed the relationship between metabolic syndrome and the occurrence of AP. We therefore elucidated the association between metabolic syndrome and the occurrence of AP.

Methods

A hospital-based case–control study was conducted. A total of 705 patients admitted to our hospital from January 2016 to December 2018 were included in the study. Subjects were divided into case and control groups according to their diagnosis: (1) According to the revised Atlanta classification from 2012, patients diagnosed with AP were enrolled in the case group. (2) Patients without a history of AP or any disease related to metabolic syndrome were allocated into the control group. Controls were matched to cases individually by sex and age (control/case ratio = 1).

Results

The incidence rate of metabolic syndrome in AP patients was 30.9%, which was more frequent than that in controls (13.2%) (OR 2.837; 95% CI 1.873–4.298, p < 0.001). In the multivariate regression analysis, a history of smoking or alcohol consumption and biliary stones were significantly associated with AP (OR 2.441; 95% CI 1.865–5.172, p < 0.001; OR 1.777; 95% CI 1.060–2.977, p = 0.029; OR 28.995; 95% CI 13.253–63.435, p < 0.001). In addition, the occurrence of AP was significantly associated with total cholesterol (TC) (OR 1.992; 95% CI 1.246–3.183, p = 0.004), triglyceride (TG) (OR 2.134; 95% CI 1.403–3.245, p < 0.001), hyperglycaemia (OR 2.261; 95% CI 1.367–3.742, p = 0.001), and apolipoprotein A (Apo A) (OR 0.270; 95% CI 0.163–0.447, p < 0.001).

Conclusions

Metabolic syndrome and its components were associated with AP occurrence.

Antioxidants Targeting Mitochondrial Oxidative Stress: Promising Neuroprotectants for Epilepsy

Mitochondria are major sources of reactive oxygen species (ROS) within the cell and are especially vulnerable to oxidative stress. Oxidative damage to mitochondria results in disrupted mitochondrial function and cell death signaling, finally triggering diverse pathologies such as epilepsy, a common neurological disease characterized with aberrant electrical brain activity. Antioxidants are considered as promising neuroprotective strategies for epileptic condition via combating the deleterious effects of excessive ROS production in mitochondria. In this review, we provide a brief discussion of the role of mitochondrial oxidative stress in the pathophysiology of epilepsy and evidences that support neuroprotective roles of antioxidants targeting mitochondrial oxidative stress including mitochondria-targeted antioxidants, polyphenols, vitamins, thiols, and nuclear factor E2-related factor 2 (Nrf2) activators in epilepsy. We point out these antioxidative compounds as effectively protective approaches for improving prognosis. In addition, we specially propose that these antioxidants exert neuroprotection against epileptic impairment possibly by modulating cell death interactions, notably autophagy-apoptosis, and autophagy-ferroptosis crosstalk.

Lycopene protects against central and peripheral neuropathy by inhibiting oxaliplatin-induced ATF-6 pathway, apoptosis, inflammation and oxidative stress in brains and sciatic tissues of rats

The fact that oxaliplatin (OXL), a platinum-based chemotherapeutic drug, causes severe neuropathy greatly limits its clinical use. This study investigated the effects of lycopene, a potent antioxidant, on OXL-induced central and peripheral neuropathy. In this study, 30 min after oral administration of LY at a dose of 2 mg/kg b.w./day and 4 mg/kg b.w./day on 1 st, 2nd, 4th and 5th days, rats were given 4 mg/kg b.w./day of OXL intraperitoneally. It was detected that LY decreased OXL-induced lipid peroxidation and increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and the levels of glutathione (GSH) in brain tissue. LY showed anti-inflammatory effects by decreasing levels of mitogen-activated protein kinase-14 (MAPK14), nuclear factor kappa-B (NF-κB) and tumor necrosis factor-α (TNF-α) in brain and sciatic tissue. It was determined that OXL-induced endoplasmic reticulum stress (ERS) decreased because LY administration reduced the expressions of activating transcription factor-6 (ATF6), glucose-regulated protein-78 (GRP78), RNA-activated protein kinase (PKR)-like ER kinase and inositol-requiring enzyme-1 (IRE1). LY administration also reduced the damage of OXL-induced brain and sciatic tissue by increasing NCAM levels and decreasing GFAP levels. It was determined that caspase-3 immunopositivity markedly decreased by OXL and LY in combination. It was also observed that LY provided neuronal protection by increasing brain-derived neurotrophic factor (BDNF) levels, which decreased with OXL administration in sciatic tissue. The results demonstrate that LY can be beneficial in ameliorating OXL-induced central and peripheral nerve injuries by showing antioxidant, anti-inflammatory and anti-apoptotic properties in the brain and sciatic tissue.

Perfluorooctane Sulfonate (PFOS) Produces Dopaminergic Neuropathology in Caenorhabditis elegans

Perfluorooctane sulfonate (PFOS) has been widely utilized in numerous industries. Due to long environmental and biological half-lives, PFOS is a major public health concern. Although the literature suggests that PFOS may induce neurotoxicity, neurotoxic mechanisms, and neuropathology are poorly understood. Thus, the primary goal of this study was to determine if PFOS is selectively neurotoxic and potentially relevant to specific neurological diseases. Nematodes (Caenorhabditis elegans) were exposed to PFOS or related per- and polyfluoroalkyl substances (PFAS) for 72 h and tested for evidence of neuropathology through examination of cholinergic, dopaminergic, gamma-amino butyric acid (GABA)ergic, and serotoninergic neuronal morphologies. Dopaminergic and cholinergic functional analyses were assessed through 1-nonanol and Aldicarb assay. Mechanistic studies assessed total reactive oxygen species, superoxide ions, and mitochondrial content. Finally, therapeutic approaches were utilized to further examine pathogenic mechanisms. Dopaminergic neuropathology occurred at lower exposure levels (25 ppm, approximately 50 µM) than required to produce neuropathology in GABAergic, serotonergic, and cholinergic neurons (100 ppm, approximately 200 µM). Further, PFOS exposure led to dopamine-dependent functional deficits, without altering acetylcholine-dependent paralysis. Mitochondrial content was affected by PFOS at far lower exposure level than required to induce pathology (≥1 ppm, approximately 2 µM). Perfluorooctane sulfonate exposure also enhanced oxidative stress. Further, mutation in mitochondrial superoxide dismutase rendered animals more vulnerable. Neuroprotective approaches such as antioxidants, PFAS-protein dissociation, and targeted (mitochondrial) radical and electron scavenging were neuroprotective, suggesting specific mechanisms of action. In general, other tested PFAS were less neurotoxic. The primary impact is to prompt research into potential adverse outcomes related to PFAS-induced dopaminergic neurotoxicity in humans.

Involvement of the nitric oxide signaling in modulation of naringin against intranasal manganese and intracerbroventricular β-amyloid induced neurotoxicity in rats

Manganese -induced aggregation of the amyloid-β peptide (Aβ) is a hallmark molecular feature of Alzheimer's disease (AD). The current study was designed to investigate the effects of chronic administration of naringin against β-A_1-42 and manganese induced experimental model. Wistar rats received intracerebroventricular (ICV) β-A_1-42 once, intranasal manganese, naringin and nitric oxide modulators for 21 days and behavioral alterations were assessed. Mitochondrial enzymes, oxidative parameters, TNF-α, β-A_1-42 acetylcholinesterase (AChE) levels and manganese concentration were measured. ICV β-A_1-42 and intranasal manganese treated rats showed a memory deficit and significantly increased in β-A_1-42 level and manganese concentration, mitochondrial oxidative damage, AChE level and inflammatory mediator in the hippocampus and cortex. Chronic administration of naringin (40 and 80 mg/kg) significantly improved memory performance and attenuated the oxidative damage and mitochondrial dysfunction in Aβ with Mn treated rats. In addition, naringin also attenuates the pro-inflammatory cytokines like TNF-α, AChE, Amyloid deposition and Mn concentration. Further, pretreatment of N(G)-Nitro-L-arginine methyl ester (L-NAME) with (5 mg/kg) with lower dose of naringin significantly potentiated its protective effect. These results demonstrate that naringin offers protection against ICV β-A_1-42 and intranasal manganese induced memory dysfunction possibly due to its antioxidant, anti-inflammatory, anti-amyloidogenesis therefore, could have a therapeutic potential in Alzheimer's disease.

Sodium ferulate attenuates high-glucose-induced oxidative injury in HT22 hippocampal cells

The aim of the present study was to investigate the protective effects of sodium ferulate (SF) on HT22 hippocampal cells under a high glucose concentration. Cells were cultured in normal glucose (25 mM D-glucose) or high glucose (50 mM D-glucose) with various concentrations of SF (50, 100, 250 or 500 µM) for 0, 48 and 72 h. Cell viability was tested using a Cell Counting Kit-8 assay. Reactive oxygen species (ROS) production was detected using flow cytometry. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nuclear factor-κB (NF-κB) at the mRNA and protein levels were detected using a reverse transcription-quantitative polymerase chain reaction analysis and western blotting. HT22 hippocampal cell viability was revealed to be substantially decreased following culturing in high glucose medium (50 mM) for 48 and 72 h. The addition of 100 µM SF abrogated this high-glucose-induced toxicity, but higher concentrations of SF (250 and 500 µM) were harmful to the cells. Furthermore, a high glucose concentration increased the generation of ROS, downregulated the expression of Nrf2/HO-1 and upregulated the expression of NF-κB subsequent to culturing for 72 h, whereas the addition of the appropriate concentration of SF attenuated these effects. To the best of our knowledge, the present study is the first to report such results and provide evidence that SF protects HT22 cells from high glucose-induced toxicity by activating the Nrf2/HO-1 pathway and inhibiting the expression of NF-κB, which may be of therapeutic value in diabetic encephalopathy.

The footprints of mitochondrial impairment and cellular energy crisis in the pathogenesis of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and Fanconi's syndrome: A comprehensive review

Fanconi's Syndrome (FS) is a disorder characterized by impaired renal proximal tubule function. FS is associated with a vast defect in the renal reabsorption of several chemicals. Inherited and/or acquired conditions seem to be connected with FS. Several xenobiotics including many pharmaceuticals are capable of inducing FS and nephrotoxicity. Although the pathological state of FS is well described, the exact underlying etiology and cellular mechanism(s) of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and FS are not elucidated. Constant and high dependence of the renal reabsorption process to energy (ATP) makes mitochondrial dysfunction as a pivotal mechanism which could be involved in the pathogenesis of FS. The current review focuses on the footprints of mitochondrial impairment in the etiology of xenobiotics-induced FS. Moreover, the importance of mitochondria protecting agents and their preventive/therapeutic capability against FS is highlighted. The information collected in this review may provide significant clues to new therapeutic interventions aimed at minimizing xenobiotics-induced renal injury, serum electrolytes imbalance, and FS.

From the Cover: Harmane-Induced Selective Dopaminergic Neurotoxicity in Caenorhabditis elegans

Parkinson's disease (PD) is a debilitating neurodegenerative disease. Although numerous exposures have been linked to PD etiology, causative factors for most cases remain largely unknown. Emerging data on the neurotoxicity of heterocyclic amines suggest that this class of compounds should be examined for relevance to PD. Here, using Caenorhabditis elegans as a model system, we tested whether harmane exposure produced selective toxicity to dopamine neurons that is potentially relevant to PD. Harmane is a known tremorigenic β-carboline (a type of heterocyclic amine) found in cooked meat, roasted coffee beans, and tobacco. Thus, this compound represents a potentially important exposure. In the nematode model, we observed dopaminergic neurons to be selectively vulnerable, showing significant loss in terms of structure and function at lower doses than other neuronal populations. In examining mechanisms of toxicity, we observed significant harmane-induced decreases in mitochondrial viability and increased reactive oxygen species levels. Blocking transport through the dopamine transporter (DAT) was not neuroprotective, suggesting that harmane is unlikely to enter the cell through DAT. However, a mitochondrial complex I activator did partially ameliorate neurodegeneration. Further, mitochondrial complex I activator treatment reduced harmane-induced dopamine depletion, measured by the 1-nonanol assay. In summary, we have shown that harmane exposure in C. elegans produces selective dopaminergic neurotoxicity that may bear relevance to PD, and that neurotoxicity may be mediated through mitochondrial mechanisms.

The effect of selective serotonin re-uptake inhibitors on risk of type II diabetes mellitus and acute pancreatitis: a meta-analysis

To explore the effect of selective serotonin re-uptake inhibitors (SSRIs) on risk of type II diabetes mellitus (T2DM) and acute pancreatitis (AP), expecting to provide guidance for clinic. Literature was retrieved by searching Pubmed, Embase, Cochrane and Scopus and hand searching of reference lists of related articles. Stata 14.0 was utilized for processing and analysis, and adjusted odds ratios (aORs) were applied. Our study included 113898 T2DM patients and 284131 controls from nine studies and 17548 AP patients and 108108 controls from four studies. The pooled aORs of SSRIs on the risk of T2DM and AP were 1.38 (95% confidence interval (CI) = 1.24–1.54) and 1.26 (95% CI = 1.13–1.40), respectively. Study design, quality, ethnicity, follow-up, and sample size of patients were the resources of heterogeneity. Subgroup analysis showed that 2 weeks is a high-risk time for AP after SSRIs use, with 1.48-fold-times as much after it. This meta-analysis provides evidence of a significant positive association between SSRIs use and risks of T2DM or AP, and duration of 2 weeks of SSRIs use has higher risk of AP, which should be paid much attention to.

Taurine supplementation abates cirrhosis-associated locomotor dysfunction

AIM OF THE STUDY

Hepatic encephalopathy and hyperammonemia is a clinical complication associated with liver cirrhosis. The brain is the target organ for ammonia toxicity. Ammonia-induced brain injury is related to oxidative stress, locomotor activity dysfunction, and cognitive deficit, which could lead to permanent brain injury, coma and death if not appropriately managed. There is no promising pharmacological intervention against cirrhosis-associated brain injury. Taurine (TAU) is one of the most abundant amino acids in the human body. Several physiological and pharmacological roles have been attributed to TAU. TAU may act as an antioxidant and is an excellent neuroprotective agent. This study aimed to evaluate the effect of TAU supplementation on cirrhosis-associated locomotor activity disturbances and oxidative stress in the brain.

MATERIAL AND METHODS

Rats underwent bile duct ligation (BDL) surgery, and plasma and brain ammonia level, plasma biochemical parameters, and rats' locomotor function were monitored. Furthermore, brain tissue markers of oxidative stress were assessed.

RESULTS

It was found that plasma and brain ammonia was increased, and markers of liver injury were significantly elevated in the cirrhotic group. Impaired locomotor activity was also evident in BDL rats. Moreover, an increase in brain tissue markers of oxidative stress was detected in the brain of cirrhotic animals. It was found that TAU supplementation (50, 100, and 200 mg/kg, gavage) alleviated brain tissue markers of oxidative stress and improved animals' locomotor activity.

CONCLUSIONS

These data suggest that TAU is a potential protective agent against cirrhosis-associated brain injury.

Phellinus rimosus improves mitochondrial energy status and attenuates nephrotoxicity in diabetic rats

BACKGROUND

Mitochondrial dysfunction and increase in reactive oxygen species during diabetes can lead to pathological consequences in kidneys. The present study was aimed to investigate the effect of Phellinus rimosus in the streptozotocin (STZ)-induced diabetic rat renal mitochondria and the possible mechanism of protection.

METHODS

Phellinus rimosus (50 and 250 mg/kg, p.o) was treated after inducing diabetes by STZ (45 mg/kg, i.p) in rats. The serum samples were subjected to creatinine and urea estimation. Mitochondrial antioxidant status such as mitochondrial superoxide dismutase, glutathione peroxidase, and reduced glutathione; adenosine triphosphate level; and lipid peroxidation were measured. The activities of Krebs cycle enzymes such as isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase as well as mitochondrial complexes I, III, and IV in kidney mitochondria were also determined.

RESULTS

Administration of P. rimosus (250 mg/kg b.wt) once daily for 30 days, significantly (p<0.05) enhanced the activities of Krebs cycle dehydrogenases, mitochondrial electron transport chain complexes, and ATP level. Further, P. rimosus had significantly protected the renal mitochondrial antioxidant status and lipid peroxidation.

CONCLUSIONS

The results of the study concluded that by limiting the extent of renal mitochondrial damage in the hyperglycemic state, P. rimosus alleviated nephrotoxicity.

Diabetes induces mitochondrial dysfunction and alters cholesterol homeostasis and neurosteroidogenesis in the rat cerebral cortex

The nervous system synthesizes and metabolizes steroids (i.e., neurosteroidogenesis). Recent observations indicate that neurosteroidogenesis is affected by different nervous pathologies. Among these, long-term type 1 diabetes, together with other functional and biochemical changes, has been shown to alter neuroactive steroid levels in the nervous system. Using an experimental model of type 1 diabetes (i.e., streptozotocin injection) we here show that the levels of these molecules are already decreased in the rat cerebral cortex after one month of the initiation of the pathology. Moreover, decreased levels of free cholesterol, together with alterations in the expression of molecules involved in cholesterol biosynthesis, bioavailability, trafficking and metabolism were detected in the rat cerebral cortex after one month of diabetes. Furthermore, mitochondrial functionality was also affected in the cerebral cortex and consequently may also contribute to the decrease in neuroactive steroid levels. Altogether, these results indicate that neurosteroidogenesis is an early target for the effect of type 1 diabetes in the cerebral cortex.

Diabetes Mellitus is Associated With Mortality in Acute Pancreatitis

BACKGROUND AND AIM

Predicting severe pancreatitis is important for early aggressive management of patients with acute pancreatitis (AP). Despite the established role of diabetes mellitus (DM) in the risk of AP, the impact of DM on the clinical outcome in AP has not been fully elucidated. The objective of this study was to assess the risk of mortality and severity in AP among patients with type-2 DM.

METHODS

Patients diagnosed with first attacks of AP were enrolled from January 2013 to June 2015.

RESULTS

A total of 201 patients (63.2% male, mean age, 59.4 y) with AP were included. Etiologies included gallstones (51.2%), alcohol (37.3%), hypertriglyceridemia (2%), and idiopathic causes (9.5%). There were 54 AP patients (26.9%) with type-2 DM. Severity indices in AP, such as Atlanta Classification (severe), Ranson score, and Bedside Index of Severity in Acute Pancreatitis, were higher in subjects with DM than those without DM. Prevalence of intensive care unit admission and mortality were higher in AP patients with DM compared with those without DM. The association between DM and increased risk of mortality in AP remained statistically significant even after adjustments for confounding factors and Atlanta Classification (odds ratio, 7.76, 95% confidence interval, 1.26-47.63, P=0.027).

CONCLUSIONS

Type-2 DM was associated with severity and increased mortality in patients with AP. Our findings provide evidence of the potential role of DM in the pathogenesis and management of severe AP.

Uncoupling Protein 2 Inhibition Exacerbates Glucose Fluctuation-Mediated Neuronal Effects

Though glucose fluctuations have been considered as an adverse factor for the development of several diabetes-related complications, their impact in the central nervous system is still not fully elucidated. This study was conducted to evaluate the responses of neuronal cells to different glycemic exposures alongside to elucidate the role of uncoupling protein 2 (UCP2) in regulating such responses. To achieve our goals, primary cortical neurons were submitted to constant high (HG)/low (LG) or glucose level variations (GVs), and the pharmacological inhibition of UCP2 activity was performed using genipin. Results obtained show that GV decreased neuronal cells' viability, mitochondrial membrane potential, and manganese superoxide dismutase activity and increased reactive oxygen species (ROS) production. GV also caused an increase in the glutathione/glutathione disulfide ratio and in the protein expression levels of nuclear factor E2-related factor 2 (NRF2), UCP2, NADH-ubiquinone oxidoreductase chain 1 (ND1), and mitochondrially encoded cytochrome c oxidase I (MTCO1), both mitochondrial DNA encoded subunits of the electron transport chain. Contrariwise, genipin abrogated all those compensations and increased the levels of caspase 3-like activity, potentiated mitochondrial ROS levels, and the loss of neuronal synaptic integrity, decreased the protein expression levels of NRF1, and increased the protein expression levels of UCP5. Further, in the control and LG conditions, genipin increased mitochondrial ROS and the protein expression levels of UCP4, postsynaptic density protein 95 (PSD95), ND1, and MTCO1. Overall, these observations suggest that UCP2 is in the core of neuronal cell protection and/or adaptation against GV-mediated effects and that other isoforms of neuronal UCPs can be upregulated to compensate the inhibition of UCP2 activity.

Mitochondria As the Target for the Modulatory Effect of Curcumin in Oxaliplatin-induced Toxicity in Isolated Rat Liver Mitochondria

BACKGROUND AND AIMS

To explore hepatoprotective action of curcumin (CMN, a bioflavonoid) on oxaliplatin (Oxa)-triggered mitochondrial oxidative stress and respiratory chain complexes in liver of rats. Oxa is a ubiquitously utilized platinum-based chemotherapeutic agent commonly used for the treatment of colorectal cancer. Mitochondria have recently emerged as targets for anticancer drugs in several kinds of toxicity including hepatotoxicity that can lead to neoplastic disease. There is a dearth of evidence involving the role of mitochondria in mediating Oxa-evoked hepatotoxicity and its underlying mechanism is still debatable.

METHODS

The study was performed in mitochondria isolated from liver of Wistar rats. Oxa (200 μg/mL) and CMN (5 μmol) were incubated under in vitro conditions.

RESULTS

Oxa evoked a significant increase in the membrane lipid peroxidation (LPO) levels, protein carbonyl (PC) contents, decrease in reduced glutathione (GSH) and nonprotein thiol (NP-SH) levels. Oxa also caused a marked decline in the activities of enzymatic antioxidants and respiratory chain enzymes (I, II, III and V) in liver mitochondria. CMN pre-treatment significantly prevented the activities of enzymatic antioxidants and mitochondrial respiratory chain enzymes. CMN also restored the LPO and PC contents, GSH and NP-SH levels in liver mitochondria.

CONCLUSION

CMN intake might be effective in regulation of Oxa-evoked mitotoxicity during chemotherapy. Moreover, it is included in the armamentarium for anticancer agent-induced oxidative stress.

Lipopolysaccharide Binding Protein and Oxidative Stress in a Multiple Sclerosis Model

Recent findings in experimental autoimmune encephalomyelitis (EAE) suggest that altering certain bacterial populations present in the gut may lead to a proinflammatory condition, that could result in the development of multiple sclerosis (MS). Also, Reactive Oxygen Species seem to be involved in the course of MS. In this study, it has been aimed to relate all these variables starting from an analysis of the lipopolysaccharide (LPS) and LPS-binding protein (LBP) with the determination of parameters related to oxidative stress in the blood, brain and spinal cord. For this purpose, samples obtained from EAE rats and relapsing-remitting (RRMS) MS patients were used. In addition, EAE rats were treated with Natalizumab, N-acetyl-cysteine and dimethyl fumarate. Natalizumab was also employed in RRMS. The results of this study revealed an improvement in the clinical symptoms of the EAE and MS with the treatments, as well as a reduction in the oxidative stress parameters and in LBP. Correlations between the clinical variables of the disease, i.e. oxidative damage and LBP, were established. Although the conclusions of this research are indeed relevant, further investigation would be necessary to establish the intrinsic mechanisms of the MS-oxidative stress-microbiota relationship.

The Effects of Ascorbate, N-Acetylcysteine, and Resveratrol on Fibroblasts from Patients with Mitochondrial Disorders

Reactive oxygen species (ROS) are assumed to be implicated in the pathogenesis of inborn mitochondrial diseases affecting oxidative phosphorylation (OXPHOS). In the current study, we characterized the effects of three small molecules with antioxidant properties (N-acetylcysteine, ascorbate, and resveratrol) on ROS production and several OXPHOS parameters (growth in glucose free medium, ATP production, mitochondrial content and membrane potential (MMP)), in primary fibroblasts derived from seven patients with different molecularly defined and undefined mitochondrial diseases. N-acetylcysteine appeared to be the most beneficial compound, reducing ROS while increasing growth and ATP production in some patients' cells. Ascorbate showed a variable positive or negative effect on ROS, ATP production, and mitochondrial content, while incubation with resveratrol disclosed either no effect or detrimental effect on ATP production and MMP in some cells. The individual responses highlight the importance of investigating multiple parameters in addition to ROS to obtain a more balanced view of the overall effect on OXPHOS when evaluating antioxidant treatment options for mitochondrial diseases.

Neuroprotective effects of melatonin as evidenced by abrogation of oxaliplatin induced behavioral alterations, mitochondrial dysfunction and neurotoxicity in rat brain

Neurotoxicity is a burdensome consequence of platinum-based chemotherapy that neutralizes the administration of effective dosage and often prompts treatment withdrawal. Oxaliplatin (Oxa), a third-era platinum analogue that is active against both early-organize and progressed colorectal growth, produces critical neurotoxicity. It has been reported that the Melatonin (Mel) is a pineal hormone its metabolites display important antioxidant properties in nervous system. There is dearth of literature involving the role of mitochondria and cytosolic compartments mediated Oxa-induced neurotoxicity and its underlying mechanisms are still debatable. Rats were pre-treated with Mel (10mg/kg b.wt., i.p.) and treated with Oxa (4mg/kg b.wt. i.p.) for 5 consecutive days. For neurobehavioral performances, decreased locomotor activity and muscular strength were observed in rats. Treatment with Mel in Oxa treated rats could protect the Oxa induced alterations in motor activity and muscular strength. For painful neuropathy, thermal hyperalgesia/nociceptive tests were evaluated. In addition, pre-treatment of Mel could block or alter the inactivation of Bcl-2, caspase 3 apoptotic protein and alterations Cytochrome c (Cyt c) release in an Oxa rich environment. Pre-treatment of Mel have shown an alteration in hyperalgesia behaviour in Oxa treated rats. Oxidative stress biomarkers, levels of non-enzymatic antioxidants and mitochondrial complexes were evaluated against neurotoxicity induced by Oxa. Mel pre-treatment replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. Mel also modulated altered non-enzymatic, enzymatic antioxidants and complex enzymes of mitochondria. Futures studies are also required to identify other molecular markers involved in neurotoxicity induced by Oxa and possible action of Mel in its modulation.

Diabetes enhances oxidative stress-induced TRPM2 channel activity and its control by N-acetylcysteine in rat dorsal root ganglion and brain

N-acetylcysteine (NAC) is a sulfhydryl donor antioxidant that contributes to the regeneration of glutathione (GSH) and also scavengers via a direct reaction with free oxygen radicals. Recently, we observed a modulatory role of NAC on GSH-depleted dorsal root ganglion (DRG) cells in rats. NAC may have a protective role on oxidative stress and calcium influx through regulation of the TRPM2 channel in diabetic neurons. Therefore, we investigated the effects of NAC on DRG TRPM2 channel currents and brain oxidative stress in streptozotocin (STZ)-induced diabetic rats. Thirty-six rats divided into four groups: control, STZ, NAC and STZ + NAC. Diabetes was induced in the STZ and STZ + NAC groups by intraperitoneal STZ (65 mg/kg) administration. After the induction of diabetes, rats in the NAC and STZ + NAC groups received NAC (150 mg/kg) via gastric gavage. After 2 weeks, DRG neurons and the brain cortex were freshly isolated from rats. In whole-cell patch clamp experiments, TRPM2 currents in the DRG following diabetes induction with STZ were gated by H2O2. TRPM2 channel current densities in the DRG and lipid peroxidation levels in the DRG and brain were higher in the STZ groups than in controls; however, brain GSH, GSH peroxidase (GSH-Px), vitamin C and vitamin E concentrations and DRG GSH-Px activity were decreased by diabetes. STZ + H2O2-induced TRPM2 gating was totally inhibited by NAC and partially inhibited by N-(p-amylcinnamoyl) anthranilic acid (ACA) and 2-aminoethyl diphenylborinate (2-APB). GSH-Px activity and lipid peroxidation levels were also attenuated by NAC treatment. In conclusion, we observed a modulatory role of NAC on oxidative stress and Ca(2+) entry through the TRPM2 channel in the diabetic DRG and brain. Since excessive oxidative stress and overload Ca(2+) entry are common features of neuropathic pain, our findings are relevant to the etiology and treatment of pain neuropathology in DRG neurons.

Selenium and zinc protect brain mitochondrial antioxidants and electron transport chain enzymes following postnatal protein malnutrition

AIMS

Selenium (Se) and zinc (Zn) are trace elements required for optimal brain functions. Thus, the role of Se and Zn against protein malnutrition induced oxidative stress on mitochondrial antioxidants and electron transport chain (ETC) enzymes from rats' brain were investigated.

MAIN METHODS

Normal protein (NP) and low protein (LP) rats were fed with diets containing 16% and 5% casein respectively for a period of 10weeks. Then the rats were supplemented with Se and Zn at a concentration of 0.15mgL(-1) and 227mgL(-1) in drinking water for 3weeks after which the rats were sacrificed.

KEY FINDINGS

The results obtained from the study showed significant (p<0.05) increase in lipid peroxidation (LPO), ROS production, oxidized glutathione (GSSG) levels and mitochondrial swelling and significant (p<0.05) reductions in catalase (CAT) and Mn-superoxide dismutase (Mn-SOD) activities, glutathione (GSH) levels, GSH/GSSG ratio and MTT reduction as a result of LP ingestion. The activities of mitochondrial ETC enzymes were also significantly inhibited in both the cortex and cerebellum of LP-fed rats. Supplementation with either Se or Zn restored the alterations in all the parameters.

SIGNIFICANCE

The study showed that Se and Zn might be beneficial in protecting mitochondrial antioxidants and ETC enzymes against protein malnutrition induced oxidative stress.

Neuroprotective activities of curcumin and quercetin with potential relevance to mitochondrial dysfunction induced by oxaliplatin

Peripheral neurotoxicity is one of the serious dose-limiting side effects of oxaliplatin (Oxa) when used in the treatment of malignant conditions. It is documented that it elicits major side effects specifically neurotoxicity due to oxidative stress forcing the patients to limit its clinical use in long-term treatment. Oxidative stress has been proven to be involved in Oxa-induced toxicity including neurotoxicity. The mitochondria have recently emerged as targets for anticancer drugs in various kinds of toxicity including neurotoxicity that can lead to neoplastic disease. However, there is paucity of literature involving the role of the mitochondria in mediating Oxa-induced neurotoxicity and its underlying mechanism is still debatable. The purpose of this study was to investigate the dose-dependent damage caused by Oxa on isolated brain mitochondria under in vitro conditions. The study was also designed to investigate the neuroprotective effects of nutraceuticals, curcumin (CMN), and quercetin (QR) on Oxa-induced mitochondrial oxidative stress and respiratory chain complexes in the brain of rats. Oxidative stress biomarkers, levels of nonenzymatic antioxidants, activities of enzymatic antioxidants, and mitochondrial complexes were evaluated against the neurotoxicity induced by Oxa. Pretreatment with CMN and QR significantly replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. CMN and QR ameliorated altered nonenzymatic and enzymatic antioxidants and complex enzymes of mitochondria. We conclude that CMN and QR, by attenuating oxidative stress as evident by mitochondrial dysfunction, hold promise as agents that can potentially reduce Oxa-induced adverse effects in the brain.

Antioxidant treatment ameliorates experimental diabetes-induced depressive-like behaviour and reduces oxidative stress in brain and pancreas

Studies have shown a relationship between diabetes mellitus (DM) and the development of major depressive disorder. Alterations in oxidative stress are associated with the pathophysiology of both diabetes mellitus and major depressive disorder. This study aimed to evaluate the effects of antioxidants N-acetylcysteine and deferoxamine on behaviour and oxidative stress parameters in diabetic rats. To this aim, after induction of diabetes by a single dose of alloxan, Wistar rats were treated with N-acetylcysteine or deferoxamine for 14 days, and then depressive-like behaviour was evaluated. Oxidative stress parameters were assessed in the prefrontal cortex, hippocampus, amygdala, nucleus accumbens and pancreas. Diabetic rats displayed depressive-like behaviour, and treatment with N-acetylcysteine reversed this alteration. Carbonyl protein levels were increased in the prefrontal cortex, hippocampus and pancreas of diabetic rats, and both N-acetylcysteine and deferoxamine reversed these alterations. Lipid damage was increased in the prefrontal cortex, hippocampus, amygdala and pancreas; however, treatment with N-acetylcysteine or deferoxamine reversed lipid damage only in the hippocampus and pancreas. Superoxide dismutase activity was decreased in the amygdala, nucleus accumbens and pancreas of diabetic rats. In diabetic rats, there was a decrease in catalase enzyme activity in the prefrontal cortex, amygdala, nucleus accumbens and pancreas, but an increase in the hippocampus. Treatment with antioxidants did not have an effect on the activity of antioxidant enzymes. In conclusion, animal model of diabetes produced depressive-like behaviour and oxidative stress in the brain and periphery. Treatment with antioxidants could be a viable alternative to treat behavioural and biochemical alterations induced by diabetes.

Bidirectional Relationship Between Diabetes and Acute Pancreatitis: A Population-Based Cohort Study in Taiwan

The proposed bidirectional relationship between acute pancreatitis (AP) and diabetes has never been examined with the same source of data. Furthermore, the effects of disease severity on this relationship have not been fully evaluated. The present study employed the findings from a single database to measure the strength of the association between AP and diabetes.Findings from 1 million National Health Insurance beneficiaries were utilized. Two cohort studies with this database were selected to evaluate the linkage between diabetes and AP. The first cohort analysis addressed the risk of AP among diabetic patients and was comprised of 42,080 diabetic patients and 672,146 unexposed subjects. The second cohort analysis considered the risk of diabetes among patients with AP and enrolled 3187 patients with AP and 709259 unexposed subjects. All adult beneficiaries were followed from January 1, 2005 to December 31, 2012 to identify outcomes of interest. Cox regression models were applied to compare hazards adjusted for potential confounders.For the first cohort, the adjusted hazard ratio (HR) of AP was significantly increased by the presence of diabetes (1.72; 95% confidence interval [CI], 1.52-1.96). In diabetic patients with a history of hyperglycemic crisis episodes (HCEs), the HR was even higher (6.32; 95% CI, 4.54-8.81). For the second cohort, the adjusted HR of diabetes in patients with AP was increased compared to the general population (2.15; 95% CI, 1.92-2.41). For patients with severe AP, the HR was also higher (2.22; 95% CI, 1.50-3.29) but did not differ significantly from that for patients with nonsevere AP.The 2 cohort studies provided evidence for the bidirectional relationship between diabetes and AP. Moreover, diabetic patients with history of HCEs may be associated with higher risk of AP.