miR-18a-5p promotes osteogenic differentiation of BMSC by inhibiting Notch2.

Postmenopausal osteoporosis (PMOP) is a metabolic disorder characterized by the loss of bone density, which increases the risk of developing complications such as fractures. A pivotal factor contributing to the onset of PMOP is the diminished osteogenic differentiation capacity of bone marrow mesenchymal stem cells (BMSCs). MicroRNAs (miRNAs) play a substantial role in this process; however, their specific impact on regulating BMSCs osteogenesis remains unclear. Studies have evidenced a reduced expression of miR-18a-5p in PMOP, and concomitantly, our observations indicate an augmented expression of miR-18a-5p during the osteogenic differentiation of BMSCs. This investigation seeks to elucidate the regulatory influence of miR-18a-5p on BMSC osteogenic differentiation and the underlying mechanisms. In vitro experiments demonstrated that the overexpression of miR-18a-5p facilitated the osteogenic differentiation of BMSCs, while the downregulation of miR-18a-5p yielded converse outcomes. Mechanistically, We employed bioinformatics techniques to screen out the target gene Notch2 of miR-18a-5p. Subsequently, dual-luciferase reporter gene assays and rescue experiments substantiated that miR-18a-5p promotes BMSC osteogenic differentiation by suppressing Notch2. Finally, miR-18a-5p was overexpressed via adenovirus injection into the femoral bone marrow cavity, with results demonstrating its capability to enhance osteogenic differentiation and alleviate PMOP symptoms. Our findings disclose that miR-18a-5p fosters osteogenic differentiation of BMSC by inhibiting Notch2, thereby offering novel targets and strategies for PMOP treatment.

Oyster mantle-derived exosomes alleviate osteoporosis by regulating bone homeostasis.

Osteoporosis is a major public health problem with an urgent need for safe and effective therapeutic interventions. The process of shell formation in oysters is similar to that of bone formation in mammals, and oyster extracts have been proven to exert osteoprotective effects. Oyster mantle is the most crucial organ regulating shell formation, in which exosomes play an important role. However, the effects of oyster mantle-derived exosomes (OMEs) on mammalian osteoporosis and the underlying mechanisms remain unknown. The OMEs investigated herein was found to carry abundant osteogenic cargos. They could also survive hostile gastrointestinal conditions and accumulate in the bones following oral administration. Moreover, they promoted osteoblastic differentiation and inhibited osteoclastic differentiation simultaneously. Further mechanistic examination revealed that OMEs likely promoted osteogenic activity by activating PI3K/Akt/ß-catenin pathway in osteoblasts and blunted osteoclastic activity by inhibiting NF-κB pathway in osteoclasts. These favorable pro-osteogenic effects of OMEs were also corroborated in a rat femur defect model. Importantly, oral administration of OMEs effectively attenuated bone loss and improved the bone microstructure in ovariectomy-induced osteoporotic mice, and demonstrating excellent biosafety. The mechanistic insights from our data support that OMEs possess promising therapeutic potential against osteoporosis.

Exerkine ß-aminoisobutyric acid protects against atrial structural remodeling and atrial fibrillation in obesity via activating AMPK signaling and improving insulin sensitivity.

Moderate exercise decreases the risk for atrial fibrillation (AF), an effect which is probably mediated via exercise-stimulated release of exerkines. ß-Aminoisobutyric acid (BAIBA), a novel exerkine, has been reported to provide protective benefits against many cardiovascular diseases, yet its role in AF remains elusive. Herein, using a mouse model of obesity-related AF through high-fat diet (HFD) feeding, we found that 12-week drinking administration of BAIBA (170 mg/kg/day) decreased AF susceptibility in obese mice. Atrial remodeling assessment showed that BAIBA attenuated obesity-induced atrial hypertrophy and interstitial fibrosis, thereby ablating the substrate for AF. Of note, to our knowledge, this is the first report of the direct association of BAIBA and hypertrophy. BAIBA has been reported to be a key regulator of glucose and lipid metabolism, and we found that BAIBA alleviated insulin resistance in obese mice. Transcriptional analysis of metabolism-related genes showed that BAIBA increased the transcription of fatty acids metabolism-related genes in the atria of lean mice but not in that of obese mice. Mechanistic investigation showed that BAIBA stimulated AMP-activated protein kinase (AMPK) signaling in the atria of obese mice and palmitic acid (PA)-treated neonatal rat cardiomyocytes (NRCM), whereas inhibition of AMPK via Compound C attenuated BAIBA-conferred cardioprotection against hypertrophy and insulin resistance in PA-treated NRCM. Collectively, BAIBA attenuates AF susceptibility in obese mice via activated AMPK signaling and resultant improvement of insulin sensitivity, thereby providing perspectives on the potential therapeutic role of BAIBA in AF treatment.

BMSC-derived exosomal miR-27a-3p and miR-196b-5p regulate bone remodeling in ovariectomized rats.

Background: In the bone marrow microenvironment of postmenopausal osteoporosis (PMOP), bone marrow mesenchymal stem cell (BMSC)-derived exosomal miRNAs play an important role in bone formation and bone resorption, although the pathogenesis has yet to be clarified. Methods: BMSC-derived exosomes from ovariectomized rats (OVX-Exo) and sham-operated rats (Sham-Exo) were co-cultured with bone marrow-derived macrophages to study their effects on osteoclast differentiation. Next-generation sequencing was utilized to identify the differentially expressed miRNAs (DE-miRNAs) between OVX-Exo and Sham-Exo, while target genes were analyzed using bioinformatics. The regulatory effects of miR-27a-3p and miR-196b-5p on osteogenic differentiation of BMSCs and osteoclast differentiation were verified by gain-of-function and loss-of-function analyses. Results: Osteoclast differentiation was significantly enhanced in the OVX-Exo treatment group compared to the Sham-Exo group. Twenty DE-miRNAs were identified between OVX-Exo and Sham-Exo, among which miR-27a-3p and miR-196b-5p promoted the expressions of osteogenic differentiation markers in BMSCs. In contrast, knockdown of miR-27a-3p and miR-196b-5p increased the expressions of osteoclastic markers in osteoclast. These 20 DE-miRNAs were found to target 11435 mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that these target genes were involved in several biological processes and osteoporosis-related signaling pathways. Conclusion: BMSC-derived exosomal miR-27a-3p and miR-196b-5p may play a positive regulatory role in bone remodeling.

High glucose protects cardiomyocytes against ischaemia/reperfusion injury by suppressing myocardiocyte apoptosis via circHIPK3/miR-29b/AKT3 signalling.

High glucose promoted expression of AKT3, a direct target gene of miR-29b, by regulating circHIPK3 that functioned as ceRNA to sponge and down-regulate miR-29b. As a potential target gene of miR-29b, AKT3 plays a crucial role in the pathogenesis of myocardial ischaemia/reperfusion (I/R) injury, and this study aimed to investigate the potential role of high glucose in the outcome of I/R injury. qPCR and luciferase assay were carried out to investigate the relationship between the expression of circHIPK3, miR-29b and ATK3 mRNA. Immunohistochemistry and TUNEL were performed to analyse the relationship between AKT3 expression and apoptosis of myocardiocytes in vivo. No obvious difference in myocardial functions was observed between I/R and control rats under hyperglycaemia (HG) and normal glucose (NG) conditions, except that the infarct size/area at risk (IS/AR) ratio and the amount of h-FABP expression were different under HG and NG conditions. The expression of circHIPK3 and ATK3 was significantly elevated in the rats preconditioned by NG, whereas the expression of miR-29a was remarkably decreased. Meanwhile, the apoptosis of myocardial tissue was reduced in the rats preconditioned by NG. Luciferase assay confirmed that miR-29a played a repressive role in the expression of circHIPK3 and ATK3. And subsequent study indicated that the over-expressed AKT3 could rescue the increased cell apoptosis rate induced by the knockdown of circHIPK3. In this study, we demonstrated that high glucose protects cardiomyocytes against I/R associated injury by suppressing apoptosis and high glucose promoted the expression of AKT3 by regulating the expression of circHIPK3/miR-29b.

FOXD3-AS1 suppresses the progression of non-small cell lung cancer by regulating miR-150/SRCIN1axis.

BACKGROUND: Long non-coding RNA (lncNRA) forkhead box D3 antisense RNA 1 (FOXD3-AS1) has been proved to promote or suppress the occurrence and development of multiple types of human tumors. However, the function and mechanism of FOXD3-AS1 in non-small cell lung cancer (NSCLC) are scarcely understood. METHODS: qRT-PCR was used for detecting FOXD3-AS1, miR-150 and SRC kinase signaling inhibitor 1 (SRCIN1) mRNA expression in NSCLC tissues, and the relationship between pathological characteristics of NSCLC patients and FOXD3-AS1 expression level was analyzed. With human NSCLC cell lines H1299 and A549 as cell models, CCK-8 and BrdU assays were employed for detecting cancer cell proliferation, and Transwell assay was employed for detecting cell invasion ability. Dual luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were used for the verification of the targeting relationshipe between FOXD3-AS1 and miR-150, and Western blot was employed for detecting SRCIN1 protein expression. RESULTS: FOXD3-AS1 expression was significantly reduced in NSCLC tissues and cell lines, and low expression of FOXD3-AS1 was closely related to positive lymph node metastasis and relatively high tumor grade. FOXD3-AS1 over-expression inhibited the proliferation and invasion of H1299 cell lines, while its knockdown promoted the proliferation and invasion of A549 cells. Additionally, it was confirmed that FOXD3-AS1 suppressed the expression of miR-150 by targeting it, and up-regulated the expression of SRCIN1. CONCLUSIONS: FOXD3-AS1 indirectly enhances the expression of SRCIN1 by targeting miR-150, thereby inhibiting NSCLC progression.

Prospective Advances in Beneficial Effects of Exercise on Human Health.

Physical inactivity increases the chance of many adverse health conditions. It has been well recognized that exercise exerts widespread beneficial effects in health promotion and disease prevention. However, there remain many unknowns in the understanding of the complex biology and performance behind diversity in response to exercise among populations and individuals. The exercise-afforded health benefits are not sufficiently researched, which to some extent holds back the translation of exercise biology to society and the widespread adoption of physical activity promotion. A comprehensive understanding of the physiology of exercise and pathogenic processes underpinning physical inactivity-associated disorders will facilitate the development of new preventative and therapeutic strategies to improve health and well-being at the whole-body level. In this chapter, we will discuss some important questions that remain to be addressed in the research of health-promoting benefits of exercise.

Moderate-intensity exercise allows enhanced protection against oxidative stress-induced cardiac dysfunction in spontaneously hypertensive rats.

The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dtmax and -LVdP/dtmax). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.

[miR-494-3p reduces insulin sensitivity in diabetic cardiomyocytes by down-regulation of insulin receptor substrate 1].

More and more evidence suggests that microRNA is widely involved in the regulation of cardiovascular function. Our preliminary experiment showed that miR-494-3p was increased in heart of diabetic rats, and miR-494-3p was reported to be related to metabolism such as obesity and exercise. Therefore, this study was aimed to explore the role of miR-494-3p in diabetic myocardial insulin sensitivity and the related mechanism. The diabetic rat model was induced by high fat diet (45 kcal% fat, 12 weeks) combined with streptozotocin (STZ, 30 mg/kg), and cardiac tissue RNA was extracted for qPCR. The results showed that the level of miR-494-3p was significantly up-regulated in the myocardium of diabetic rats compared with the control (P < 0.05). The level of miR-494-3p in H9c2 cells cultured in high glucose and high fat medium (HGHF) was significantly increased (P < 0.01) with the increase of sodium palmitate concentration, whereas down-regulation of miR-494-3p in HGHF treated cells led to an increase in insulin-stimulated glucose uptake (P < 0.01) and the ratio of p-Akt/Akt (P < 0.05). Over-expression of miR-494-3p in H9c2 cell line significantly inhibited insulin-stimulated glucose uptake and phosphorylation of Akt (P < 0.01). Bioinformatics combined with Western blotting experiments confirmed insulin receptor substrate 1 (IRS1) as a target molecule of miR-494-3p. These results suggest that miR-494-3p reduces insulin sensitivity in diabetic cardiomyocytes by down-regulating IRS1.

Longterm Exercise-Derived Exosomal miR-342-5p: A Novel Exerkine for Cardioprotection

RATIONALE: Exercise training, in addition to reducing cardiovascular risk factors, confers direct protection against myocardial ischemia/reperfusion injury and has been associated with improved heart attack survival in humans. However, the underlying mechanisms of exercise-afforded cardioprotection are still unclear. OBJECTIVE: To investigate the role of exercise-derived circulating exosomes in cardioprotection and the molecular mechanisms involved. METHODS AND RESULTS: Circulating exosomes were isolated from the plasma of volunteers with or without exercise training and rats subjected to 4-week swim exercise or sedentary littermates 24 hours after the last training session. Although the total circulating exosome level did not change significantly in exercised subjects 24 hours post-exercise compared with the sedentary control, the isolated plasma exosomes from exercised rats afforded remarkable protection against myocardial ischemia/reperfusion injury. miRNA sequencing combined with quantitative reverse transcription polymerase chain reaction validation identified 12 differentially expressed miRNAs from the circulating exosomes of exercised rats, among which miR-342-5p stood out as the most potent cardioprotective molecule. Importantly, the cardioprotective effects and the elevation of exosomal miR-342-5p were also observed in exercise-trained human volunteers. Moreover, inhibition of miR-342-5p significantly blunted the protective effects of exercise-derived circulating exosomes in hypoxia/reoxygenation cardiomyocytes; in vivo cardiac-specific inhibition of miR-342-5p through serotype 9 adeno-associated virus-mediated gene delivery attenuated exercise-afforded cardioprotection in myocardial ischemia/reperfusion rats. Mechanistically, miR-342-5p inhibited hypoxia/reoxygenation-induced cardiomyocyte apoptosis via targeting Caspase 9 and Jnk2; it also enhanced survival signaling (p-Akt) via targeting phosphatase gene Ppm1f. Of note, exercise training or laminar shear stress directly enhanced the synthesis of miR-342-5p in endothelial cells. CONCLUSIONS: Our findings reveal a novel endogenous cardioprotective mechanism that long-term exercise-derived circulating exosomes protect the heart against myocardial ischemia/reperfusion injury via exosomal miR-342-5p.

Moderate-intensity exercise allows enhanced protection against oxidative stress-induced cardiac dysfunction in spontaneously hypertensive rats

The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dtmax and −LVdP/dtmax). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.

Short-Duration Swimming Exercise after Myocardial Infarction Attenuates Cardiac Dysfunction and Regulates Mitochondrial Quality Control in Aged Mice.

BACKGROUND: Exercise benefits to cardiac rehabilitation (CR) following stable myocardial infarction (MI). The suitable exercise duration for aged patients with coronary heart disease (CHD) remains controversial, and the underlying molecular mechanism is still unclear. METHODS AND RESULTS: 18-Month-old mice after stable MI were randomly submitted to different durations of exercise, including 15 and 60 min swimming training (ST) once per day, five times a week for 8 weeks. Compared to sedentary mice, 15 min ST, rather than 60 min ST, significantly augmented left ventricular function, increased survival rate, and suppressed myocardial fibrosis and apoptosis. 15 min ST improved mitochondrial morphology via regulating mitochondrial fission-fusion signaling. 15 min ST regulated mitophagy signaling via inhibiting LC3-II and P62 levels and increasing PINK/Parkin expression. 15 min ST also inhibited ROS production and enhanced antioxidant SOD2 activity. Notably, 15 min ST significantly increased sirtuin (SIRT) 3 level (2.7-fold) in vivo while the inhibition of SIRT3 exacerbated senescent H9c2 cellular LDH release and ROS production under hypoxia. In addition, SIRT3 silencing impairs mitochondrial dynamics and mitophagy in senescent cardiomyocytes against simulated ischemia (SI) injury. CONCLUSION: Collectively, our study demonstrated for the first time that sustained short-duration exercise, rather than long-duration exercise, attenuates cardiac dysfunction after MI in aged mice. It is likely that the positive regulation induced by a short-duration ST regimen on the elevated SIRT3 protein level improved mitochondrial quality control and decreased apoptosis and fibrosis contributed to the observed more resistant phenotype.

Quaternary ammonium salt of U50,488H elicits protective effects against hypoxic pulmonary hypertension.

The present study aimed to investigate the role of quaternary ammonium salt of U50,488H (Q-U50,488H) in hypoxic pulmonary hypertension (HPH) and underlying mechanisms involved. A HPH animal model was established in rats under hypoxia and the mean pulmonary arterial pressure (mPAP) and right ventricular pressure (RVP) were measured. Relaxation of the pulmonary artery in response to Q-U50,488H was determined. In addition, expression and activity of endothelial nitric oxide (NO) synthase (eNOS) and inducible NO synthase (iNOS) with NO content, Akt expression, total antioxidant capacity (T-AOC), and gp91phox were evaluated. Cell viability was determined by the cell counting kit-8 (CCK-8) assay. We demonstrated that both the molecular weight and solubility of Q-U50,488H were higher than that of U50,488H. Q-U50,488H reduced mPAP and RVP and prevented the development of HPH. Moreover, Q-U50,488H relaxed the pulmonary arteries from both normal and HPH rats in a time-dependent manner. Under hypoxic conditions, Q-U50,488H significantly increased Akt phosphorylation, eNOS phosphorylation, NO content in serum, and T-AOC in pulmonary arteries of HPH rats. In addition, the activity of eNOS was elevated, but the activity of iNOS was reduced when Q-U50,488H was given under hypoxia. Q-U50,488H significantly counteracted the increase of gp91phox expression in pulmonary arteries under hypoxia. In addition, in vitro studies suggested that Q-U50,488H inhibited pulmonary artery smooth muscle cells (PASMCs) proliferation under hypoxic conditions and that the effects of Q-U50,488H were blocked by nor-binaltorphimine (nor-BNI). Thus, our results provided evidence that Q-U50,488H plays a protective role against HPH via κ-opioid receptor stimulation.

Alpha7 nicotinic acetylcholine receptor activation protects against myocardial reperfusion injury through modulation of autophagy.

Alpha7 nicotinic acetylcholine receptor (α7nAChR) activation alleviates myocardial ischemia/reperfusion (MI/R) injury. However, the underlying mechanisms remain unclear. Here, we investigated the role of autophagy in α7nAChR-mediated cardioprotection and the molecular mechanisms involved. Activating α7nAChR with PNU-282987 at the initiation of reperfusion reduced myocardial infarct size in MI/R rats. PNU-282987 treatment also significantly inhibited MI/R-induced myocardial autophagy dysfunction as evidenced by the reduction of LC3-II/LC3-I ratio, Beclin-1 and p62 abundance. In addition, PNU-282987 treatment reduced hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury in vitro, accompanied with the inhibition of Beclin-1-associated autophagy and the restoration of autophagic flux. Interestingly, inhibiting autophagic flux attenuated α7nAChR-afforded improvement of mitochondrial function as well as inhibition of apoptosis in vitro. Mechanistically, co-administration of PNU-282987 with LY294002 (a PI3K inhibitor), AG490 (a JAK2 inhibitor) or Bcl-2 siRNA, but not compound C (an AMPK inhibitor), reduced Bcl-2 level and prevented the modulation of autophagy afforded by PNU-282987 in H/R cardiomyocytes. Collectively, these findings suggest that α7nAChR activation inhibits Beclin-1-associated autophagy dysfunction via the JAK2/Bcl-2 and PI3K/Bcl-2 cascades, leading to cardioprotection against MI/R injury.

Enhancing fatty acid utilization ameliorates mitochondrial fragmentation and cardiac dysfunction via rebalancing optic atrophy 1 processing in the failing heart.

Aims: Heart failure (HF) is characterized by reduced fatty acid (FA) utilization associated with mitochondrial dysfunction. Recent evidence has shown that enhancing FA utilization may provide cardioprotection against HF. Our aim was to investigate the effects and the underlying mechanisms of cardiac FA utilization on cardiac function in response to pressure overload. Methods and results: Transverse aortic constriction (TAC) was used in C57 mice to establish pressure overload-induced HF. TAC mice fed on a high fat diet (HFD) exhibited increased cardiac FA utilization and improved cardiac function and survival compared with those on control diet. Such cardioprotection could also be provided by cardiac-specific overexpression of CD36. Notably, both HFD and CD36 overexpression attenuated mitochondrial fragmentation and improved mitochondrial function in the failing heart. Pressure overload decreased ATP-dependent metalloprotease (YME1L) expression and induced the proteolytic cleavage of the dynamin-like guanosine triphosphatase OPA1 as a result of suppressed FA utilization. Enhancing FA utilization upregulated YME1L expression and subsequently rebalanced OPA1 processing, resulting in restoration of mitochondrial morphology in the failing heart. In addition, cardiac-specific overexpression of YME1L exerted similar cardioprotective effects against HF to those provided by HFD or CD36 overexpression. Conclusions: These findings demonstrate that enhancing FA utilization ameliorates mitochondrial fragmentation and cardiac dysfunction via rebalancing OPA1 processing in pressure overload-induced HF, suggesting a unique metabolic intervention approach to improving cardiac functions in HF.

Antihypertensive effects of Tartary buckwheat flavonoids by improvement of vascular insulin sensitivity in spontaneously hypertensive rats.

Vascular insulin resistance and oxidative stress contribute to endothelial dysfunction and hypertension. The present study investigated whether chronic treatment with purified Tartary buckwheat flavonoids fraction (TBF) prevents the development of hypertension via improving vascular insulin sensitivity and reducing oxidative stress. Six-week-old male spontaneously hypertensive rats (SHRs) and their normotensive Wistar-Kyoto (WKY) control rats were subjected to different dosages of TBF for 8 weeks. Blood pressure, mesenteric arteriolar vasorelaxation, superoxide anion (O2-) generation, NAD(P)H oxidase activity, and insulin-stimulated Akt/endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) production were determined. The SHRs had higher systolic blood pressure, systemic insulin resistance, and impaired vasodilator actions of insulin and the insulin signaling pathway in mesenteric arterioles when compared with the WKY rats. TBF treatment at a dosage of 100 mg kg-1 day-1 significantly reduced systolic blood pressure and increased vasodilator response to insulin in the SHRs. Additionally, TBF treatment significantly reduced phosphorylation of insulin receptor substrate 1 (IRS-1) at serine 307 and increased insulin-stimulated Akt/eNOS activation in the SHRs. Furthermore, TBF treatment reduced the overproduction of basal O2- in association with a reduction of NAD(P)H oxidase activity in mesenteric arterioles of the SHRs. Finally, quercetin was identified as the predominant active component of TBF in attenuating the development of hypertension with regard to reducing vascular oxidative stress, regulating the vascular insulin signaling pathway and restoring vasodilator response to insulin in the SHRs. In conclusion, TBF possesses protective effects against hypertension through attenuating vascular insulin resistance and oxidative stress.

Tartary buckwheat flavonoids ameliorate high fructose-induced insulin resistance and oxidative stress associated with the insulin signaling and Nrf2/HO-1 pathways in mice.

The present study was conducted to explore the effects of a purified tartary buckwheat flavonoid fraction (TBF) on insulin resistance and hepatic oxidative stress in mice fed high fructose in drinking water (20%) for 8 weeks. The results indicated that continuous administration of TBF dose-dependently improved the insulin sensitivity and glucose intolerance in high fructose-fed mice. TBF treatment also reversed the reduced level of insulin action on the phosphorylation of insulin receptor substrate-1 (IRS-1), protein kinase B (Akt) and phosphatidylinositol 3-kinase (PI3K), as well as the translocation of glucose transporter type 4 (GLUT4) in the insulin-resistant liver. Furthermore, TBF was found to exert high antioxidant capacity as it acts as a shield against oxidative stress induced by high fructose by restoring the antioxidant status, and modulating nuclear factor E2 related factor 2 (Nrf2) translocation to the nucleus with subsequently up-regulated antioxidative enzyme protein expression. Histopathological examinations revealed that impaired pancreatic/hepatic tissues were effectively restored in high fructose-fed mice following TBF treatment. Our results show that TBF intake is effective in preventing the conversion of high fructose-induced insulin resistance and hepatic oxidative stress in mice by improving the insulin signaling molecules and the Nrf2 signal pathway in the liver.

Combined administration of a sedative dose sevoflurane and 60% oxygen reduces inflammatory responses to sepsis in animals and in human PMBCs.

Our study aims to investigate the effects of the inhalation of subanesthestic doses of sevoflurane combined with oxygen on sepsis. Male Sprague-Dawley rats or Male ICR/Km mice underwent caecal ligation and puncture (CLP) or intraperitoneal injection of lipopolysccharide (LPS) to induce sepsis, while sham rats were used as control. Then, rats were treated with the inhalation of sevoflurane in oxygen; and air or 100% oxygen was used as control. Seven-day survival, lung injury and inflammatory factors were assessed. In this in vitro experiment, we obtained RAW264.7 macrophages and human peripheral blood mononuclear cells (PBMCs) incubated by LPS or plasma from septic patients to explore the NF-κB pathway in the effect of the inhalation of sevoflurane combined with oxygen in sepsis. In this study, we found that the inhalation of 0.5 MAC of sevoflurane in 60% oxygen was the best protocol for protecting against lethality resulting from sepsis and ALI, and there was a time window for these protective effects. We also founded that 0.5 MAC of sevoflurane in 60% oxygen inhibited the nuclear translocation of NF-κB in human PBMCs induced by LPS or plasma from septic patients. The subanesthesia dose sevoflurane in 60% oxygen may reduce sepsis-induced inflammatory responses in animals and in PBMCs, and the inhibition to the activation of the NF-κB pathway may contribute to this protection.

Glucose oxidation positively regulates glucose uptake and improves cardiac function recovery after myocardial reperfusion.

Myocardial reperfusion decreases glucose oxidation and uncouples glucose oxidation from glycolysis. Therapies that increase glucose oxidation lessen myocardial ischemia-reperfusion (I/R) injury. However, the regulation of glucose uptake during reperfusion remains poorly understood. We found that glucose uptake was remarkably diminished in the myocardium following reperfusion in Sprague-Dawley rats as detected by 18F-labeled and fluorescent-labeled glucose analogs, even though GLUT1 was upregulated by threefold and GLUT4 translocation remained unchanged compared with those of sham-treated rats. The decreased glucose uptake was accompanied by suppressed glucose oxidation. Interestingly, stimulating glucose oxidation by inhibition of pyruvate dehydrogenase kinase 4 (PDK4), a rate-limiting enzyme for glucose oxidation, increased glucose uptake and alleviated I/R injury. In vitro data in neonatal myocytes showed that PDK4 overexpression decreased glucose uptake, whereas its knockdown increased glucose uptake, suggesting that PDK4 has a role in regulating glucose uptake. Moreover, inhibition of PDK4 increased myocardial glucose uptake with concomitant enhancement of cardiac insulin sensitivity following myocardial I/R. These results showed that the suppressed glucose oxidation mediated by PDK4 contributes to the reduced glucose uptake in the myocardium following reperfusion, and enhancement of glucose uptake exerts cardioprotection. The findings suggest that stimulating glucose oxidation via PDK4 could be an efficient approach to improve recovery from myocardial I/R injury.

Sub-anesthesia Dose of Isoflurane in 60% Oxygen Reduces Inflammatory Responses in Experimental Sepsis Models.

BACKGROUND: Sepsis is a major cause of mortality in Intensive Care Units. Anesthetic dose isoflurane and 100% oxygen were proved to be beneficial in sepsis; however, their application in septic patients is limited because long-term hyperoxia may induce oxygen toxicity and anesthetic dose isoflurane has potential adverse consequences. This study was scheduled to find the optimal combination of isoflurane and oxygen in protecting experimental sepsis and its mechanisms. METHODS: The effects of combined therapy with isoflurane and oxygen on lung injury and sepsis were determined in animal models of sepsis induced by cecal ligation and puncture (CLP) or intraperitoneal injection of lipopolysaccharide (LPS) or zymosan. Mouse RAW264.7 cells or human peripheral blood mononuclear cells (PBMCs) were treated by LPS to probe mechanisms. The nuclear factor kappa B (NF-κB) signaling molecules were examined by Western blot and cellular immunohistochemistry. RESULTS: The 0.5 minimum alveolar concentration (MAC) isoflurane in 60% oxygen was the best combination of oxygen and isoflurane for reducing mortality in experimental sepsis induced by CLP, intraperitoneal injection of LPS, or zymosan. The 0.5 MAC isoflurane in 60% oxygen inhibited proinflammatory cytokines in peritoneal lavage fluids (tumor necrosis factor-alpha [TNF-ß]: 149.3 vs. 229.7 pg/ml, interleukin [IL]-1ß: 12.5 vs. 20.6 pg/ml, IL-6: 86.1 vs. 116.1 pg/ml, and high-mobility group protein 1 [HMGB1]: 323.7 vs. 449.3 ng/ml; all P< 0.05) and serum (TNF-ß: 302.7 vs. 450.7 pg/ml, IL-1ß: 51.7 vs. 96.7 pg/ml, IL-6: 390.4 vs. 722.5 pg/ml, and HMGB1: 592.2 vs. 985.4 ng/ml; all P< 0.05) in septic animals. In vitro experiments showed that the 0.5 MAC isoflurane in 60% oxygen reduced inflammatory responses in mouse RAW264.7 cells, after LPS stimulation (all P< 0.05). Suppressed activation of NF-κB pathway was also observed in mouse RAW264.7 macrophages and human PBMCs after LPS stimulation or plasma from septic patients. The 0.5 MAC isoflurane in 60% oxygen also prevented the increases of phospho-IKKß/ß, phospho-IκBß, and phospho-p65 expressions in RAW264.7 macrophages after LPS stimulation (all P< 0.05). CONCLUSION: Combined administration of a sedative dose of isoflurane with 60% oxygen improves survival of septic animals through reducing inflammatory responses.