Nicotine promotes e-cigarette vapour-induced lung inflammation and structural alterations.

BACKGROUND: Electronic cigarette (e-cigarette) vapour is gaining popularity as an alternative to tobacco smoking and can induce acute lung injury. However, the specific role of nicotine in e-cigarette vapour and its long-term effects on the airways, lung parenchyma and vasculature remain unclear. RESULTS: In vitro exposure to nicotine-containing e-cigarette vapour extract (ECVE) or to nicotine-free e-cigarette vapour extract (NF ECVE) induced changes in gene expression of epithelial cells and pulmonary arterial smooth muscle cells (PASMCs), but ECVE in particular caused functional alterations (e.g. a decrease in human and mouse PASMC proliferation by 29.3±5.3% and 44.3±8.4%, respectively). Additionally, acute inhalation of nicotine-containing e-cigarette vapour (ECV) but not nicotine-free e-cigarette vapour (NF ECV) increased pulmonary endothelial permeability in isolated lungs. Long-term in vivo exposure of mice to ECV for 8 months significantly increased the number of inflammatory cells, in particular lymphocytes, compared to control and NF ECV in the bronchoalveolar fluid (BALF) (ECV: 853.4±150.8 cells·mL-1; control: 37.0±21.1 cells·mL-1; NF ECV: 198.6±94.9 cells·mL-1) and in lung tissue (ECV: 25.7±3.3 cells·mm-3; control: 4.8±1.1 cells·mm-3; NF ECV: 14.1±2.2 cells·mm-3). BALF cytokines were predominantly increased by ECV. Moreover, ECV caused significant changes in lung structure and function (e.g. increase in airspace by 17.5±1.4% compared to control), similar to mild tobacco smoke-induced alterations, which also could be detected in the NF ECV group, albeit to a lesser degree. In contrast, the pulmonary vasculature was not significantly affected by ECV or NF ECV. CONCLUSIONS: NF ECV components induce cell type-specific effects and mild pulmonary alterations, while inclusion of nicotine induces significant endothelial damage, inflammation and parenchymal alterations.

New insights into the cytoprotective mechanism of nano curcumin on neuronal damage in a vincristine-induced neuropathic pain rat model.

Vincristine is a frequently used antineoplastic drug for treating a variety of malignancies, although its usage has been restricted by the painful neuropathy it induces. A more profound comprehension of the pathogenesis of vincristine-induced painful neuropathy (VIPN) is crucial for developing efficient preventive and therapeutic approaches. With its well-established anti-inflammatory and immunomodulatory actions, curcumin (nanoemulsion form) was utilized in our work as a protective and therapeutic tool for VIPN. This study aims to clarify the mechanisms behind curcumin's neuroprotective effects against vincristine-induced neurotoxicity. For painful neuropathy induction, rats were injected with vincristine sulfate (150µg/kg/i.p.: once every two days) for five injections. For treatment, pregabalin (30 mg/kg/p.o.), curcumin (30mg/kg/p.o.) and curcumin nanoemulsion (30mg/kg/p.o.) were administered daily for 14 consecutive days. Our results showed that curcumin nanoemulsion significantly reduced cold allodynia and thermal hyperalgesia. It also increased the sciatic nerve levels of [CAT, SOD and IL-10] and the spinal cord PPAR-γ. Additionally, immunostaining of the sciatic nerve revealed a reduction in NF-κB expression and an increase in HSP70 expression. These findings suggest that curcumin has neuroprotective effects against VIPN, which might be attributed to its interference with the PPAR-γ, HSP70 and IL-10 signaling pathways.

The Effect of Chronic Activation of the Novel Endocannabinoid Receptor GPR18 on Myocardial Function and Blood Pressure in Conscious Rats.

Although acute activation of the novel endocannabinoid receptor GPR18 causes hypotension, there are no reports on GPR18 expression in the heart or its chronic modulation of cardiovascular function. In this study, after demonstrating GPR18 expression in the heart, we show that chronic (2 weeks) GPR18 activation with its agonist abnormal cannabidiol (abn-cbd; 100 µg·kg·d; i.p) produced hypotension, suppressed the cardiac sympathetic dominance, and improved left ventricular (LV) function (increased the contractility index dp/dtmax and reduced LV end-diastolic pressure, LVEDP) in conscious rats. Ex vivo studies revealed increased: (1) cardiac and plasma adiponectin (ADN) levels; (2) vascular (aortic) endothelial nitric oxide synthase (eNOS) expression, (3) vascular and serum nitric oxide (NO) levels; (4) myocardial and plasma cyclic guanosine monophosphate (cGMP) levels; (5) phosphorylation of myocardial protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) along with reduced myocardial reactive oxygen species (ROS) in abn-cbd treated rats. These biochemical responses contributed to the hemodynamic responses and were GPR18-mediated because concurrent treatment with the competitive GPR18 antagonist (O-1918) abrogated the abn-cbd-evoked hemodynamic and biochemical responses. The current findings present new evidence for a salutary cardiovascular role for GPR18, mediated, at least partly, via elevation in the levels of adiponectin.

Experimental evidence for the therapeutic potential of tempol in the treatment of acute liver injury.

Oxidative stress is one of the mechanisms involved in the acute carbon tetrachloride (CCl4)-induced hepatotoxicity. Since 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, known as tempol, has powerful antioxidant properties, we investigated its potential hepatoprotective effects and the underlying mechanisms that may add further benefits for its clinical usefulness using an acute model of CCl4-induced hepatotoxicity. One hour after CCl4 induction of acute hepatotoxicity, mice were treated with a daily dose of 20 mg/kg/day tempol for 3 days. It was found that treatment of animals with tempol significantly negated the pathological changes in liver function parameters as well as histology induced by CCl4. In addition, tempol significantly ameliorated CCl4-induced lipid peroxidation and GSH depletion, and improved catalase activity. Furthermore, tempol alleviated the inflammation induced by CCl4 as indicated by reducing the liver expression level of nuclear factor-kappa B (NF-κB) and tumor necrosis factor-α (TNF-α). Finally, tempol significantly reduced expression level of the B-cell lymphoma-2 protein (Bcl-2) and active caspase-3 which are known markers of apoptosis. In conclusion, the present study provides important evidences for the promising hepatoprotective effects of tempol that can be explained by amelioration of oxidative stress mainly through replenishment of GSH, restoration of antioxidant enzyme activities, and reduction of lipid peroxides alongside its anti-inflammatory properties.

Effects of dimethylarginine dimethylaminohydrolase-1 overexpression on the response of the pulmonary vasculature to hypoxia.

Acute and sustained hypoxic pulmonary vasoconstriction (HPV), as well as chronic pulmonary hypertension (PH), is modulated by nitric oxide (NO). NO synthesis can be decreased by asymmetric dimethylarginine (ADMA), which is degraded by dimethylarginine dimethylaminohydrolase-1 (DDAH1). We investigated the effects of DDAH1 overexpression (DDAH1(tg)) on HPV and chronic hypoxia-induced PH. HPV was measured during acute (10 min) and sustained (3 h) hypoxia in isolated mouse lungs. Chronic PH was induced by the exposure of mice to 4 weeks of hypoxia. ADMA and cyclic 3',5'-guanosine monophosphate (cGMP) were determined by ELISA, and NO generation was determined by chemiluminescence. DDAH1 overexpression exerted no effects on acute HPV. However, DDAH1(tg) mice showed decreased sustained HPV compared with wild-type (WT) mice. Concomitantly, ADMA was decreased, and concentrations of NO and cGMP were significantly increased in DDAH1(tg). The administration of either Nω-nitro-l-arginine or 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one potentiated sustained HPV and partly abolished the differences in sustained HPV between WT and DDAH1(tg) mice. The overexpression of DDAH1 exerted no effect on the development of chronic hypoxia-induced PH. DDAH1 overexpression selectively decreased the sustained phase of HPV, partly via activation of the NO-cGMP pathway. Thus, increased ADMA concentrations modulate sustained HPV, but not acute HPV or chronic hypoxia-induced PH.

Lectin-like oxidized low-density lipoprotein receptor 1 pathways.

BACKGROUND: The role of lectin-like oxidized low-density lipoprotein receptor (LOX)-1 has been implicated in the pathogenesis of different diseases, including atherosclerosis, hypertension, obesity, diabetes mellitus and metabolic syndrome. To date, several studies aimed at partially investigating the mechanistic role of LOX-1 in these various pathologies. Still, so far, the precise signal transduction pathways involving LOX-1 have not yet been elucidated. MATERIALS AND METHODS: The most recent data published by the authors as well as others concerning different pathways involving LOX-1 are collected to formulate the presented updated review. RESULTS: One of the most prominent pathways highlighted in the present review is the relationship of LOX-1 to NADPH oxidase that acts as a major source of harmful free radicals causing oxidative stress in blood vessels. Other pathways involve lipid and glucose metabolism-mediated signal transduction. DISCUSSION: The modulatory role of LOX-1 on nitric oxide and renin/angiotensin systems as well as on fibrosis, apoptosis and inflammatory pathways is discussed. CONCLUSION: The current review revisits LOX-1 and its related pathways, implicating LOX-1 as a target for ameliorating various pathological conditions.

Adipogenetic effects of retrofractamide A derivatives in 3T3-L1 cells.

In a previous study, retrofractamide A from the fruit of Piper chaba was shown to promote adipogenesis in 3T3-L1 cells. In the present study, retrofractamide A and its derivatives were synthesized, and their adipogenetic effects in 3T3-L1 cells were examined. Among the tested compounds, an amide composed of 9-(3',4'-methylenedioxyphenyl)-nona-2E,4E,8E-trienoic acid and an n-butyl or n-pentyl amine showed strongest activity. Moreover, the amide with the n-pentyl amine moiety significantly increased the uptake of 2-deoxyglucose into the cells, and also increased the mRNA levels of adiponectin, peroxisome proliferator-activated receptor γ2 (PPARγ2), glucose transporter 4 (GLUT4), fatty acid-binding protein (aP2), and CCAAT/enhancer-binding protein (C/EBP) α and ß in a similar manner as the PPARγ agonist troglitazone, although it had less agonistic activity against PPARγ.

Hepatoprotective effect of the selective mineralocorticoid receptor antagonist, eplerenone against carbon tetrachloride-induced liver injury in rats.

BACKGROUND: Eplerenone is a selective mineralocorticoid receptor (MR) antagonist, and its potential protective role in cardiovascular injury has been reported by several studies. However, whether and how this drug can ameliorate hepatic injury in rats is unknown. MATERIAL AND METHODS: The present study was conducted to investigate effect of eplerenone against liver injury induced by carbon tetrachloride (CCl(4)) in rats. The biochemical liver function tests and oxidative stress parameters including malondialdehyde (MDA), reactive oxygen species (ROS), in addition to the reduced glutathione (GSH) levels were evaluated. Moreover, serum tumor necrotic factors (TNF-α) level and histopathological changes were examined. RESULTS: Our results show that pre-treatment with eplerenone (4 mg/kg per day for 4 weeks) revealed attenuation in serum activities of alanine aminotransferase (ALT), aspartate aminotransferase, (AST), alkaline phosphatase (ALP) and bilirubin levels that were enhanced by CCl(4). Further, pre-treatment with eplerenone inhibited the elevated hepatic MDA content and restored hepatic GSH to its normal level. The enhanced hepatic ROS production in CCl(4)-treated group was markedly decreased by eplerenone administration. Eplerenone pre-treatment significantly attenuated the inflammatory responses caused by CCl(4) as evident by the decreased serum TNF-α level. Histopathological studies showed that eplerenone alleviated the liver damage and reduced the lesions caused by CCl(4). CONCLUSION: Collectively, the present study provides a proof to hepatoprotective actions of eplerenone via reducing oxidative stress and inflammatory responses in CCl(4)-induced liver damage in rat model.

Selective Targeting of the Novel CK-10 Nanoparticles to the MDA-MB-231 Breast Cancer Cells.

The main objective of this project was to formulate novel decorated amphiphilic PLGA nanoparticles aiming for the selective delivery of the novel peptide (CK-10) to the cancerous/tumor tissue. Novel modified microfluidic techniques were used to formulate the nanoparticles. This technique was modified by using of Nano Assemblr associated with salting out of the organic solvent using K2HPO4. This modification is associated with higher peptide loading efficiencies, smaller size and higher uniformity. Size, zeta potential & qualitative determination of the adsorbed targeting ligands were measured by dynamic light scattering and laser anemometry techniques using the zeta sizer. Quantitative estimation of the adsorbed targeting ligands was done by colorimetry and spectrophotometric techniques. Qualitative and quantitative uptakes of the various PLGA nanoparticles were examined by the fluorescence microscope and the flow cytometer while the cytotoxic effect of the nanoparticles was measured by the colorimetric MTT assay. PLGA/poloxamer.FA, PLGA/poloxamer.HA, and PLGA/poloxamer.Tf have breast cancer MDA. MB321 cellular uptakes 83.8, 75.43 & 69.37 % which are higher than those of the PLGA/B cyclodextrin.FA, PLGA/B cyclodextrin.HA and PLGA/B cyclodextrin.Tf 80.87, 74.47 & 64.67 %. Therefore, PLGA/poloxamer.FA and PLGA/poloxamer.HA show higher cytotoxicity than PLGA/ poloxamer.Tf with lower breast cancer MDA-MB-231 cell viabilities 30.74, 39.15 & 49.23 %, respectively. The design of novel decorated amphiphilic CK-10 loaded PLGA nanoparticles designed by the novel modified microfluidic technique succeeds in forming innovative anticancer formulations candidates for therapeutic use in aggressive breast cancers.

Mitochondrial Regulation of the Hypoxia-Inducible Factor in the Development of Pulmonary Hypertension.

Pulmonary hypertension (PH) is a severe progressive lung disorder characterized by pulmonary vasoconstriction and vascular remodeling, culminating in right-sided heart failure and increased mortality. Data from animal models and human subjects demonstrated that hypoxia-inducible factor (HIF)-related signaling is essential in the progression of PH. This review summarizes the regulatory pathways and mechanisms of HIF-mediated signaling, emphasizing the role of mitochondria in HIF regulation and PH pathogenesis. We also try to determine the potential to therapeutically target the components of the HIF system for the management of PH.

Brain Targeting of Citicoline Sodium via Hyaluronic Acid-Decorated Novel Nano-Transbilosomes for Mitigation of Alzheimer's Disease in a Rat Model: Formulation, Optimization, in vitro and in vivo Assessment.

Background: Alzheimer's disease (AD) is one of the furthermost advanced neurodegenerative disorders resulting in cognitive and behavioral impairment. Citicoline sodium (CIT) boosts the brain's secretion of acetylcholine, which aids in membrane regeneration and repair. However, it suffers from poor blood-brain barrier (BBB) permeation, which results in lower levels of CIT in the brain. Purpose: This study targeted to encapsulate CIT into novel nano-platform transbilosomes decorated with hyaluronic acid CIT-HA*TBLs to achieve enhanced drug delivery from the nose to the brain. Methods: A method of thin-film hydration was utilized to prepare different formulae of CIT-TBLs using the Box-Behnken design. The optimized formula was then hyuloranated via integration of HA to form the CIT-HA*TBLs formula. Furthermore, AD induction was performed by aluminum chloride (Alcl3), animals were allocated, and brain hippocampus tissue was isolated for ELISA and qRT-PCR analysis of malondialdehyde (MDA), nuclear factor kappa B (NF-kB), and microRNA-137 (miR-137) coupled with immunohistochemical amyloid-beta (Aß1-42) expression and histopathological finding. Results: The hyuloranated CIT-HA*TBLs formula, which contained the following ingredients: PL (300 mg), Sp 60 (43.97 mg), and SDC (20 mg). They produced spherical droplets at the nanoscale (178.94 ±12.4 nm), had a high entrapment efficiency with 74.92± 5.54%, had a sustained release profile of CIT with 81.27 ±3.8% release, and had ex vivo permeation of CIT with 512.43±19.58 µg/cm2. In vivo tests showed that CIT-HA*TBL thermogel dramatically reduces the hippocampus expression of miR-137 and (Aß1-42) expression, boosting cholinergic neurotransmission and decreasing MDA and NF-kB production. Furthermore, CIT-HA*TBLs thermogel mitigate histopathological damage in compared to the other groups. Conclusion: Succinctly, the innovative loading of CIT-HA*TBLs thermogel is a prospectively invaluable intranasal drug delivery system that can raise the efficacy of CIT in Alzheimer's management.

Dihydromyricetin protects against high glucose-induced endothelial dysfunction: Role of HIF-1α/ROR2/NF-κB.

OBJECTIVES: Dihydromyricetin (DHM), a natural flavonoid isolated from vine tea with anti-inflammatory activity was evaluated for its ability to prevent vascular endothelial dysfunction caused by hyperglycaemia. METHODS: Vasoconstrictor (phenylephrine-PE) and vasodilator (acetylcholine-ACh) responses were monitored for female rat aorta rings maintained in a bioassay organ bath for 3 h at 37 °C in either low (LG: 10 mM) or high (HG: 40 mM, to mimic hyperglycaemia) glucose-Krebs buffer in the absence or presence of 50 µM DHM. Tissues recovered from the organ bath at 3 h were fixed and analyzed for morphological changes and their expression of eNOS, iNOS, HIF-1α, GLUT1, ROR2 tyrosine kinase, NF-κB, TNF-α, Bax, Bcl2, caspase-3, and forindices of increased oxidative stress. KEY FINDINGS: HG-incubated tissues showed increased PE-stimulated contractile response and decreased ACh-mediated endothelial vasodilation. DHM prevented both of these changes. Besides, HG incubation increased the immunoreactivity to iNOS, HIF-1α, GLUT1, ROR2, NF-κB, TNF-α, Bax, and active caspase-3, and decreased the expression of eNOS and Bcl2. Hyperglycaemia-like conditions also increased the indices of oxidative/nitrosative stress. These HG-induced changes, which were accompanied by an increase in tissue adventitial thickness and inflammatory cell infiltration, were all prevented by DHM. CONCLUSION: Our data demonstrate an anti-inflammatory protective action of DHM to preserve vascular function in the setting of hyperglycaemia.

Green tea ameliorates renal oxidative damage induced by gentamicin in rats.

Recent studies indicate that free radicals are important mediators of renal damage induced by gentamicin (GM), an aminoglycoside antibiotic widely used in treating severe gram-negative infections. Green tea extract (GTE) was reported to have antioxidant and free radical scavenging activities. Therefore, the aim of this work was to investigate the possible protective effect of GTE against gentamicin-induced nephrotoxicity. For this purpose, rats were divided into four groups. Group-1 (control) received normal saline. Group-2 received GTE (300 mg/kg/d, orally). Group-3 received gentamicin (80 mg/kg/d, intraperitoneally). Group-4 was injected with GTE plus gentamicin simultaneously. Daily urinary total protein levels were estimated to assess kidney dysfunction. The rats were sacrificed on the seventh day and kidneys were collected for histopathological studies. Blood urea nitrogen (BUN) and creatinine levels were measured in the blood. Moreover, glutathione (GSH), lipid peroxide expressed as thiobarbituric acid reactive substance (TBARS) levels, superoxide dismutase (SOD) and catalase (CAT) activities were determined in renal tissues. GM produced elevation in urinary total protein, BUN, serum creatinine and TBARS levels. On the other hand, GM reduced the GSH level and SOD, CAT activities. The simultaneous administration of GTE plus gentamicin protected kidney tissues against nephrotoxic effect of gentamicin as evidenced from amelioration of histopathological alterations and normalization of kidney biochemical parameters.

Targeting the heme-oxidized nitric oxide receptor for selective vasodilatation of diseased blood vessels.

ROS are a risk factor of several cardiovascular disorders and interfere with NO/soluble guanylyl cyclase/cyclic GMP (NO/sGC/cGMP) signaling through scavenging of NO and formation of the strong oxidant peroxynitrite. Increased oxidative stress affects the heme-containing NO receptor sGC by both decreasing its expression levels and impairing NO-induced activation, making vasodilator therapy with NO donors less effective. Here we show in vivo that oxidative stress and related vascular disease states, including human diabetes mellitus, led to an sGC that was indistinguishable from the in vitro oxidized/heme-free enzyme. This sGC variant represents what we believe to be a novel cGMP signaling entity that is unresponsive to NO and prone to degradation. Whereas high-affinity ligands for the unoccupied heme pocket of sGC such as zinc-protoporphyrin IX and the novel NO-independent sGC activator 4-[((4-carboxybutyl){2-[(4-phenethylbenzyl)oxy]phenethyl}amino) methyl [benzoic]acid (BAY 58-2667) stabilized the enzyme, only the latter activated the NO-insensitive sGC variant. Importantly, in isolated cells, in blood vessels, and in vivo, BAY 58-2667 was more effective and potentiated under pathophysiological and oxidative stress conditions. This therapeutic principle preferentially dilates diseased versus normal blood vessels and may have far-reaching implications for the currently investigated clinical use of BAY 58-2667 as a unique diagnostic tool and highly innovative vascular therapy.

Role of ursodeoxycholic acid in prevention of hepatotoxicity caused by amoxicillin-clavulanic acid in rats.

Incidence of hepatotoxicity caused by the broad spectrum antibiotic combination amoxicillin-clavulanic acid (Co-amoxyclav) has been increasingly recognized and the mechanism of this toxicity remains undefined. On the other hand, Ursodeoxycholic acid (UDCA) has been suggested as efficient antioxidant therapy in various liver diseases. Therefore, the present study was designed to elucidate the possible role of oxidative stress in hepatotoxicity induced by Co-amoxyclav and the putative protective role of UDCA in rats. Effects of amoxicillin (Amox; 50 mg/kg, orally, 21 d) or clavulanic acid (Clav; 10 mg/kg, orally, 21 d) and their combined administration on the biochemical liver parameters, reduced glutathione (GSH), lipid peroxidation measured as hepatic malondialdehyde (MDA) levels. In addition, myeloperoxidase (MPO) activity and reactive oxygen species (ROS) production in liver homogenate were also evaluated. On the other hand, the protective effects of pretreatment with UDCA (20 mg/kg, orally, 21 d) on these parameters were also evaluated. Our results show that pretreatment with UDCA reduced the liver parameters that were enhanced by single or combined administration of Amox and/or Clav such as serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and serum bilirubin levels. Moreover, pretreatment with UDCA normalized the GSH level and inhibited the elevation in hepatic MDA concentration. The enhanced MPO activity and ROS production in liver homogenate of rats treated with Clav or Co-amoxyclav were also normalized by UDCA pretreatment. In conclusion, the present data suggest that UDCA acts as effective hepatoprotective agent against liver dysfunction caused by Co-amoxyclav and this effect is related to its antioxidant properties.

Hepatoprotective effect of pentoxifylline against D-galactosamine-induced hepatotoxicity in rats.

The present study was conducted to investigate effect of pentoxifylline (PTX) on acute liver injury caused by galactosamine (D-Gal) in rats and the underlying mechanism involved in this setting. Moreover, we attempted to compare its effect to the well-established hepatoprotective agent, silymarin (SYM). The rats were randomly assigned 5 groups, control, PTX-treated (100 mg/kg, 3 weeks), SYM-treated (100 mg/kg, 3 weeks) and their combination. Hepatic injury was induced by intraperitoneal single dose injection of D-Gal (800 mg/kg). Hepatic functions parameters, including serum albumin and alkaline phosphatase (ALP) levels were determined. Antioxidants enzyme activities such as superoxide dismutase (SOD), catalase (CAT) as well as lipid peroxides and hepatic total nitrites were measured. Besides, histopathological examination was also performed using portions of liver tissues. Results showed that the liver injury induced by D-Gal was improved in the three pretreated groups to variable extents. Pretreatment with PTX prevented D-Gal-induced reduction of antioxidant enzyme activities, SOD and CAT, and attenuated the elevated malonaldahyde (MDA) level in hepatic tissue as marker of lipid peroxidation. In addition, pretreatment with PTX resulted in an increase in hepatic triglycerides, normalization of nitric oxide level, and lowering serum ALP activity as well as inhibited the decreased serum albumin level caused by D-Gal. These biochemical changes were reflected on attenuation the structural alterations of the liver integrity. Collectively, our data suggest that PTX exhibits a potential hepatoprotective effect against D-Gal-induced hepatotoxicity and this effect might be attributed to its antioxidant properties.

Heme oxygenase-1 contributes to the protective effect of resveratrol against endothelial dysfunction in STZ-induced diabetes in rats.

Endothelial dysfunction is a common complication of diabetes that mainly stems from increased reactive oxygen species, which makes antioxidants of great benefit. Resveratrol (RSV) is an antioxidant that shows protective effects in a variety of disease models where the ameliorative effect appears to be mediated, in part, via heme oxygenase-1 (HO-1) induction. However, the pathophysiological relevance of HO-1 in the ameliorative response of RSV in endothelial dysfunction is not clearly defined. The present study was conducted to investigate whether HO-1 plays a role in diabetes-induced vascular dysfunction. Streptozotocin-diabetic rats were treated with RSV (10 mg/kg) in presence or absence of an HO-1 blocker, Zinc protoporphyrin (ZnPP) to assess vascular function and indicators of disease status. We found that RSV treatment significantly abrogated diabetes induced vascular dysfunction. This improvement was associated with the ability of RSV to decrease oxidative stress markers alongside a reduction in the aortic TGF-ß expression, elevation of NOS3 expression and aortic nitrite concentration as well as HO activity. These ameliorative effects were diminished when ZnPP was administered prior to RSV. Our results clearly demonstrate the protective effects of RSV in diabetes-associated endothelial dysfunction and verified a causal role of HO-1 in this setting.

Lixisenatide ameliorates cerebral ischemia-reperfusion injury via GLP-1 receptor dependent/independent pathways.

Ischemic stroke is a major cause of neurological damage and brain dysfunction with consequent strong cerebral oxidative imbalance, inflammatory and apoptotic responses. Lixisenatide is a new potent glucagon-like peptide -1 (GLP-1) analogue that has been used clinically in the treatment of type II diabetes. Recent studies suggested the beneficial central effects of GLP-1-based therapies on different neurodegenerative diseases. This study aimed to investigate the ameliorative effect of lixisenatide in global cerebral ischemia-reperfusion (I/R) rat model and elaborate the underline mechanisms that could mediate the proposed activity. Adult male Wistar rats were subjected to sham operation or global cerebral I/R injury. Rats were administered the following drugs in two scheduled doses at 1 h and 24 h after reperfusion: lixisenatide (1 and 10 nmole/kg), lixisenatide plus GLP-1 receptor (GLP-1R) antagonist (exendin(9-39)), and pentoxiphylline. Comparable to pentoxiphylline; both doses of lixisenatide produced a significant reduction in infarct volume and amelioration of neurobehavioural functions along with suppression of oxidative stress parameters (catalase, reduced glutathione, malondialdehyde and NO), inflammatory marker (tumor necrosis factor-alpha) and apoptotic marker (caspase-3) in ischemic rat brains. However, these effects weren'tinhibited by GLP-1R antagonist, exendin(9-39), indicating that they are independent on GLP-1R mediation. Also, lixisenatide upregulated protein expression of cerebral endothelial nitric oxide synthase and the angiogenic marker, vascular endothelial growth factor. It's worth noting that this effect was blocked by exendin(9-39). Overall, these data indicated that lixisenatide may offer a promising approach for alleviating cerebral I/R injury via different mechanisms that could be mediated, in part, through GLP-1R.

Lixisenatide, a novel GLP-1 analog, protects against cerebral ischemia/reperfusion injury in diabetic rats.

Type 2 diabetes mellitus (T2DM) is a major risk factor for ischemic stroke accompanied by vascular dysfunction and poor cerebrovascular outcome. Lixisenatide is a glucagon like peptide-1 (GLP-1) analog that is recently used for T2DM treatment with established neuroprotective properties. This study investigated and compared the neuroprotective effect of lixisenatide against glimepiride on diabetic rats subjected to global cerebral ischemia/reperfusion (I/R) injury. T2DM-induced adult male Wistar rats were administered lixisenatide or glimepiride prior to induction of global cerebral I/R-induced injury. Results showed a disturbance in oxidative stress parameters (catalase, reduced glutathione, and malondialdehyde) along with increasing in caspase-3 and tumor necrosis factor-alpha protein expressions in ischemic diabetic brain tissues. An upregulation of protein level of inducible nitric oxide (iNOS) synthase and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit, NOX2 gene expression associated with significant suppression of endothelial nitric oxide synthase (eNOS) protein expression are recorded in carotid arteries of diabetic I/R-injured rats. Apart from ameliorating glucose intolerance and insulin resistance, lixisenatide was found to be superior to glimepiride as protective treatment in terms of enhancing behavioral/neurological functions and suppressing cerebral oxidative stress, inflammation, and apoptosis in cerebral I/R-injured diabetic rats. Unlike glimepiride, lixisenatide relieved carotid endothelial dysfunction by increasing eNOS expression. It also dampened vascular nitrosative/oxidative stress via suppression of iNOS and NADPH oxidase expressions. This study supposed that lixisenatide represents a more suitable anti-diabetic therapy for patients who are at risk of ischemic stroke, and even so, the mechanisms of lixisenatide-mediated vascular protection warrant further experimental and clinical investigations.

Abnormal cannabidiol confers cardioprotection in diabetic rats independent of glycemic control.

Chronic GPR18 activation by its agonist abnormal cannabidiol (trans-4-[3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentyl-1,3-benzenediol; abn-cbd) improves myocardial redox status and function in healthy rats. Here, we investigated the ability of abn-cbd to alleviate diabetes-evoked cardiovascular pathology and the contribution of GPR18 to this effect. Four weeks after diabetes induction by streptozotocin (STZ, 55mg/kg; i.p), male Wistar rats received abn-cbd, the GPR18 antagonist (1,3-dimethoxy-5-methyl-2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-,cyclohexen-1-yl]benzene;O-1918), their combination (100µg/kg/day, i.p, each) or their vehicle for 2 weeks. Abn-cbd had no effect on diabetes-evoked cardiac hypertrophy or impaired glycemic control (hyperglycemia and hypoinsulinemia), but alleviated the associated reductions in left ventricular (LV) contractility (dP/dtmax) and relaxation (dP/dtmin) indices, and the increases in LV end diastolic pressure (LVEDP) and cardiac vagal dominance. Abn-cbd also reversed myocardial oxidative stress by restoring circulating and cardiac nitric oxide (NO) and adiponectin (ADN) levels and enhancing GPR18 expression and phosphorylation of Akt, ERK1/2 and eNOS in diabetic rats' hearts. Concurrent GPR18 blockade (O-1918) abrogated all favorable effects of abn-cbd in diabetic rats. Collectively, the current findings present evidence for abn-cbd alleviation of diabetes-evoked cardiovascular anomalies likely via GPR18 dependent restoration of cardiac adiponectin-Akt-eNOS signaling and the diminution of myocardial oxidative stress.