Obesity-Induced Coronary Microvascular Disease Is Prevented by iNOS Deletion and Reversed by iNOS Inhibition

Coronary microvascular disease (CMD) caused by obesity and diabetes is major contributor to heart failure with preserved ejection fraction; however, the mechanisms underlying CMD are not well understood. Using cardiac magnetic resonance applied to mice fed a high-fat, high-sucrose diet as a model of CMD, we elucidated the role of inducible nitric oxide synthase (iNOS) and 1400W, an iNOS antagonist, in CMD. Global iNOS deletion prevented CMD along with the associated oxidative stress and diastolic and subclinical systolic dysfunction. The 1400W treatment reversed established CMD and oxidative stress and preserved systolic/diastolic function in mice fed a high-fat, high-sucrose diet. Thus, iNOS may represent a therapeutic target for CMD.

Health Benefits of Plant-Based Nutrition: Focus on Beans in Cardiometabolic Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, claiming over 650,000 American lives annually. Typically not a singular disease, CVD often coexists with dyslipidemia, hypertension, type-2 diabetes (T2D), chronic system-wide inflammation, and obesity. Obesity, an independent risk factor for both CVD and T2D, further worsens the problem, with over 42% of adults and 18.5% of youth in the U.S. categorized as such. Dietary behavior is a most important modifiable risk factor for controlling the onset and progression of obesity and related disease conditions. Plant-based eating patterns that include beans and legumes support health and disease mitigation through nutritional profile and bioactive compounds including phytochemical. This review focuses on the characteristics of beans and ability to improve obesity-related diseases and associated factors including excess body weight, gut microbiome environment, and low-grade inflammation. Additionally, there are growing data that link obesity to compromised immune response and elevated risk for complications from immune-related diseases. Body weight management and nutritional status may improve immune function and possibly prevent disease severity. Inclusion of beans as part of a plant-based dietary strategy imparts cardiovascular, metabolic, and colon protective effects; improves obesity, low-grade inflammation, and may play a role in immune-related disease risk management.

Tempol ameliorates polycystic ovary syndrome through attenuating intestinal oxidative stress and modulating of gut microbiota composition-serum metabolites interaction

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder, which is often accompanied by oxidative stress. Tempol, a superoxide dismutase mimetic, protects against several diseases caused by oxidative stress. However, the effect of tempol on PCOS has not been investigated. The present study demonstrated the alleviation of ovarian dysfunction and glucose tolerance in dehydroepiandrosterone (DHEA)-induced PCOS rats treated with tempol. Tempol significantly reduced the intestinal oxidative stress in PCOS rats without affecting the ovarian redox rate. The 16S rDNA sequencing of the intestinal microbiome and non-targeted metabolomics analysis indicated significant differences in gut microbiota composition and serum metabolite profiles between the control and PCOS rats, and most of these differences were reduced after tempol intervention. Tempol alters the gut microbiome by increasing the abundance of genus Ruminococcus_1 and by decreasing the abundance of Ruminococcus_2, Staphylococcus, Ideonella, and Corynebnacterium genera. Tempol also attenuates the reduction of serum bile acid and stachyose levels in PCOS rats, and the serum stachyose level was significantly correlated with the abundance of 15 genera, particularly Ruminococcus_1 and Ruminococcus_2. Moreover, stachyose administration improved ovarian dysfunction in PCOS rats. Thus, our data indicate that tempol ameliorates PCOS phenotype by reducing intestinal oxidative stress, restoring gut dysbiosis, and modulating the interaction between gut microbiota and host metabolite. Therefore, tempol intervention is a potential therapeutic approach for PCOS.

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Tempol improved ovarian dysfunction and glucose tolerance in polycystic ovary syndrome rats.

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Tempol ameliorates intestinal oxidative stress and gut microbiota dysbiosis.

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The protective effect of tempol is associated alternations in serum bile acid and stachyose levels.

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Stachyose administration improved ovarian dysfunction in polycystic ovary syndrome rats.

A renal-cerebral-peripheral sympathetic reflex mediates insulin resistance in chronic kidney disease

Background

Insulin resistance (IR) complicates chronic kidney disease (CKD). We tested the hypothesis that CKD activates a broad reflex response from the kidneys and the white adipose tissue to impair peripheral glucose uptake and investigated the role of salt intake in this process.

Methods

5/6-nephrectomized rats were administered normal- or high-salt for 3 weeks. Conclusions were tested in 100 non-diabetic patients with stage 3–5 CKD.

Findings

High-salt in 5/6-nephrectomized rats decreased insulin-stimulated 2-deoxyglucose uptake >25% via a sympathetic nervous system (SNS) reflex that linked the IR to reactive oxygen species (ROS) and the renin-angiotensin system (RAS) in brain and peripheral tissues. Salt-loading in CKD enhanced inflammation in adipose tissue and skeletal muscle, and enhanced the impairment of insulin signaling and Glut4 trafficking. Denervation of the kidneys or adipose tissue or deafferentation of adipose tissue improved IR >40%. In patients with non-diabetic CKD, IR was positively correlated with salt intake after controlling for cofounders (r = 0.334, P = 0.001) and was linked to activation of the RAS/SNS and to impaired glucose uptake in adipose tissue and skeletal muscle, all of which depended on salt intake.

Interpretation

CKD engages a renal/adipose-cerebral-peripheral sympathetic reflex that activates the RAS/ROS axes to promote IR via local inflammation and impaired Glut4 trafficking that are enhanced by high-salt intake. The findings point to a role for blockade of RAS or α-and-β-adrenergic receptors to reduce IR in patients with CKD.

Fund

National Natural Science Foundation of China.

High salt intake shifts the mechanisms of flow-induced dilation in the middle cerebral arteries of Sprague-Dawley rats

The goal of the present study was to examine the effect of 1 wk of high salt (HS) intake and the role of oxidative stress in changing the mechanisms of flow-induced dilation (FID) in isolated pressurized middle cerebral arteries of male Sprague-Dawley rats ( n = 15–16 rats/group). Reduced FID in the HS group was restored by intake of the superoxide scavenger tempol (HS + tempol in vivo group). The nitric oxide (NO) synthase inhibitor Nω-nitro-l-arginine methyl ester, cyclooxygenase inhibitor indomethacin, and selective inhibitor of microsomal cytochrome P-450 epoxidase activity N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide significantly reduced FID in the low salt diet-fed group, whereas FID in the HS group was mediated by NO only. Cyclooxygenase-2 mRNA (but not protein) expression was decreased in the HS and HS + tempol in vivo groups. Hypoxia-inducible factor-1α and VEGF protein levels were increased in the HS group but decreased in the HS + tempol in vivo group. Assessment by direct fluorescence of middle cerebral arteries under flow revealed significantly reduced vascular NO levels and increased superoxide/reactive oxygen species levels in the HS group. These results suggest that HS intake impairs FID and changes FID mechanisms to entirely NO dependent, in contrast to the low-salt diet-fed group, where FID is NO, prostanoid, and epoxyeicosatrienoic acid dependent. These changes were accompanied by increased lipid peroxidation products in the plasma of HS diet-fed rats, increased vascular superoxide/reactive oxygen species levels, and decreased NO levels, together with increased expression of hypoxia-inducible factor-1α and VEGF.

NEW & NOTEWORTHY High-salt (HS) diet changes the mechanisms of flow-induced dilation in rat middle cerebral arteries from a combination of nitric oxide-, prostanoid-, and epoxyeicosatrienoic acid-dependent mechanisms to, albeit reduced, a solely nitric oxide-dependent dilation. In vivo reactive oxygen species scavenging restores flow-induced dilation in HS diet-fed rats and ameliorates HS-induced increases in the transcription factor hypoxia-inducible factor-1α and expression of its downstream target genes.

Effect of tempol on peripheral neuropathy in diet-induced obese and high-fat fed/low-dose streptozotocin-treated C57Bl6/J mice

In this study, we sought to determine the efficacy of tempol on multiple neuropathic endpoints in a diet-induced obese mouse, a model of pre-diabetes, and a high-fat fed low-dose streptozotocin treated mouse, a model of type 2 diabetes. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperdine -1-oxyl) is a low molecular weight, water soluble, membrane permeable, and metal-independent superoxide dismutase mimetic that has been widely used in cellular studies for the removal of intracellular and extracellular superoxide. This in vivo study was designed to be an early intervention. Fourteen weeks post-high-fat diet (6 weeks post-hyperglycemia) control, obese, and diabetic mice were divided into no treatment and treatment groups. The treated mice received tempol by gavage (150 mg/kg in water), while the untreated mice received vehicle. The diet-induced obese and the diabetic mice were maintained on the high-fat diet for the duration of the study, while the control group was maintained on the standard diet. Obesity and diabetes caused slowing of motor and sensory nerve conduction, reduction in intraepidermal nerve fiber density, thermal hypoalgesia, and mechanical allodynia. Treatment with tempol partially or completely protected obese and diabetic mice from these deficits. These studies suggest that tempol or other effective scavengers of reactive oxygen species may be a viable option for treating neural complications associated with obesity or type 2 diabetes.

Punicalagin Prevents Hypoxic Pulmonary Hypertension via Anti-Oxidant Effects in Rats

Punicalagin (PG), a major bioactive ingredient in pomegranate juice, has been proven to have anti-oxidative stress properties and to exert protective effects on acute lung injuries induced by lipopolysaccharides. This study aimed to investigate the effects of PG treatment on hypoxic pulmonary hypertension (HPH) and the underlying mechanisms responsible for the effects. Rats were exposed to 10% oxygen for 2 wk (8 h/day) to induce the HPH model. PG (5, 15, 45[Formula: see text]mg/kg) was orally administered 10[Formula: see text]min before hypoxia each day. PG treatments at the doses of 15 and 45[Formula: see text]mg/kg/d decreased the mean pulmonary arterial pressure (mPAP) and alleviated right ventricular hypertrophy and vascular remodeling in HPH rats. Meanwhile, PG treatment attenuated the hypoxia-induced endothelial dysfunction of pulmonary artery rings. The beneficial effects of PG treatment were associated with improved nitric oxide (NO)-cGMP signaling and reduced oxidative stress, as evidenced by decreased superoxide generation, gp91[Formula: see text] expression and nitrotyrosine content in the pulmonary arteries. Furthermore, tempol’s scavenging of oxidative stress also increased NO production and attenuated endothelial dysfunction and pulmonary hypertension in HPH rats. Combining tempol and PG did not exert additional beneficial effects compared to tempol alone. Our study indicated for the first time that PG treatment can protect against hypoxia-induced endothelial dysfunction and pulmonary hypertension in rats, which may be induced via its anti-oxidant actions.

Impact of Superoxide Dismutase Mimetic AEOL 10150 on the Endothelin System of Fischer 344 Rats

Endothelin-1 is a potent vasoconstrictor and mitogenic peptide involved in the regulation of vasomotor tone and maintenance of blood pressure. Oxidative stress activates the endothelin system, and is implicated in pulmonary and cardiovascular diseases including hypertension, congestive heart failure, and atherosclerosis. Superoxide dismutase mimetics designed with the aim of treating diseases that involve reactive oxygen species in their pathophysiology may exert a hypotensive effect, but effects on the endothelin system are unknown. Our objective was to determine the effect of the superoxide dismutase mimetic AEOL 10150 on the basal endothelin system in vivo. Male Fischer-344 rats were injected subcutaneously with 0, 2 or 5 mg/kg body weight of AEOL 10150 in saline. Plasma oxidative stress markers and endothelins (bigET-1, ET-1, ET-2, ET-3) as well as lung and heart endothelin/nitric oxide system gene expressions were measured using HPLC-Coularray, HPLC-Fluorescence and RT-PCR respectively. AEOL 10150 reduced (p<0.05) the circulating levels of isoprostane (-25%) and 3-nitrotyrosine (-50%) measured in plasma 2h and 24h after treatment, confirming delivery of a physiologically-relevant dose and the potent antioxidant activity of the drug. The reduction in markers of oxidative stress coincided with sustained 24h decrease (p<0.05) of plasma levels of ET-1 (-50%) and ET-3 (-10%). Expression of preproET-1 and endothelin converting enzyme-1 mRNA were not altered significantly in the lungs. However preproET-1 (not significant) and ECE-1 mRNA (p<0.05) were increased (10-25%) in the heart. Changes in the lungs included decrease (p<0.05) of mRNA for the ET-1 clearance receptor ETB and the vasoconstriction-signaling ETA receptor (-30%), and an early surge of inducible nitric oxide synthase expression followed by sustained decrease (-40% after 24 hours). The results indicate that interception of the endogenous physiological flux of reactive nitrogen species and reactive oxygen species in rats impacts the endothelin/nitric oxide system, supporting a homeostatic relationship between those systems.

Ramipril protects the endothelium from high glucose-induced dysfunction through CaMKKβ/AMPK and heme oxygenase-1 activation

This study aims to investigate the effects of ramipril (RPL) on endothelial dysfunction associated with diabetes mellitus using cultured human aortic endothelial cells (HAECs) and a type 2 diabetic animal model. The effect of RPL on vasodilatory function in fat-fed, streptozotocin-treated rats was assessed. RPL treatment of 8 weeks alleviated insulin resistance and inhibited the decrease in endothelium-dependent vasodilation in diabetic rats. RPL treatment also reduced serum advanced glycation end products (AGE) concentration and rat aorta reactive oxygen species formation and increased aorta endothelium heme oxygenase-1 (HO-1) expression. Exposure of HAECs to high concentrations of glucose induced prolonged oxidative stress, apoptosis, and accumulation of AGEs. These effects were abolished by incubation of ramiprilat (RPT), the active metabolite of RPL. However, treatment of HAECs with STO-609, a CaMKKβ (Ca(2+)/calmodulin-dependent protein kinase kinase-β) inhibitor; compound C, an AMPK (AMP-activated protein kinase) inhibitor; and Zn(II)PPIX, a selective HO-1 inhibitor, blocked these beneficial effects of RPT. In addition, RPT increased nuclear factor erythroid 2-related factor-2 (Nrf-2) nuclear translocation and activation in a CaMKKβ/AMPK pathway-dependent manner, leading to increased expression of the Nrf-2-regulated antioxidant enzyme, HO-1. The inhibition of CaMKKβ or AMPK by pharmaceutical approach ablated RPT-induced HO-1 expression. Taken together, RPL ameliorates insulin resistance and endothelial dysfunction in diabetes via reducing oxidative stress. These effects are mediated by RPL activation of CaMKK-β, which in turn activates the AMPK-Nrf-2-HO-1 pathway for enhanced endothelial function.

miR-223: An inflammatory oncomiR enters the cardiovascular field

MicroRNAs (miRNAs) are small, noncoding RNAs of 18-22 nucleotides in length that regulate post-transcriptional expression by base-pairing with target mRNAs. It is now clearly established that miRNAs are involved in most of the cell's physiopathological processes (including carcinogenesis and metabolic disorders). This review focuses on miR-223, which was first described as a modulator of hematopoietic lineage differentiation. We outline the role of miR-223 deregulation in several types of cancers and highlight its inclusion in a newly identified and fast-growing family of miRNAs called oncomiRs. We then look at miR-223's emerging role in inflammatory and metabolic disorders, with a particular focus on muscle diseases, type II diabetes, atherosclerosis and vascular calcification. miR-223 is one of the growing number of RNA biomarkers of various human metabolic diseases and is thus of special interest to both researchers and clinicians in the cardiovascular field.

Tranilast alleviates endothelial dysfunctions and insulin resistance via preserving glutathione peroxidase 1 in rats fed a high-fat emulsion

We investigated the effects of treatment with tranilast on vascular and metabolic dysfunction induced by a high-fat emulsion intragastric administration. Wistar rats were randomized to receive water or high-fat emulsion with or without tranilast treatment (400 mg/kg per day) for 4 weeks. Insulin sensitivity was determined with a hyperinsulinemic-euglycemic clamp experiment and short insulin tolerance test. Vascular reactivity was evaluated using aortic rings in organ chambers. Glutathione peroxidase 1 (GPX1) expressions, eNOS phosphorylation and activity, MCP-1, H2O2 formation, and NO production were determined in vascular or soleus tissues. Tranilast treatment was found to prevent alterations in vascular reactivity and insulin sensitivity and to prevent increases in plasma glucose and insulin noted in the high-fat emulsion-treated rats. These were associated with increased antioxidant enzyme GPX1 expression, eNOS phosphorylation and activity, and NO production, but reductions in H2O2 accumulation. Moreover, tranilast preserved GPX1 expression in palmitic acid (PA)-treated endothelial cells with a consequent decreased ROS formation and increased eNOS phosphorylation and NO production. Therefore, oxidative stress induced by a relatively short-term high-fat diet could cause the early development of vascular and metabolic abnormalities in rats, and tranilast has a beneficial effect in vascular dysfunctions and insulin resistance via preserving GPX1 and alleviating oxidative stress.