PPARγ-PI3K/AKT-NO signal pathway is involved in cardiomyocyte hypertrophy induced by high glucose and insulin

Association between life's essential 8 and diabetic kidney disease: a population-based study

BACKGROUND AND AIMS

Diabetic patients are highly susceptible to cardiovascular and renal diseases. As a newly updated comprehensive index for assessing cardiovascular health (CVH), Life's essential 8 (LE8) has the potential to serve as a practical tool for evaluating the risk of diabetic kidney disease (DKD). We are committed to exploring the relationship between LE8 and its subscales with DKD in diabetic patients, aiming to provide preliminary evidence for the formulation of clinical strategies.

METHODS AND RESULTS

A total of 3,715 NHANES participants were included in this study, representing 18.9 million non-institutionalized residents of the United States. The mean age of all subjects was 59.72 years, and the weighted prevalence of DKD among diabetic patients was 36.39%. After adjusting for potential confounding factors, it was found that compared to the low LE8 group, the risk of developing DKD was significantly lower in the moderate LE8 group (OR: 0.54, 95% CI: 0.43-0.66) and the high LE8 group (OR: 0.18, 95% CI: 0.08-0.42). A similar trend was observed across the subscales of the LE8 score. The results of the fully adjusted restricted cubic spline regression analysis revealed a linear relationship between LE8 and its subscales with DKD. The findings remained consistent in subgroup and sensitivity analyses, with no significant interactions observed between subgroups.

CONCLUSION

Higher scores on the LE8 and its subscales were associated with a lower risk of developing DKD. However, the long-term causal relationship between LE8 and DKD risk necessitates further validation and exploration through large-scale, rigorously designed prospective studies.

Interventional effects of exercise on neuropathy in patients with diabetes: a systematic review with meta-analysis

OBJECTIVE

This study aims to systematically evaluate the effects of exercise interventions on neurological dysfunction in diabetic patients, addressing inconsistencies in existing research. It seeks to clarify the impact of different exercise parameters and patient characteristics on nerve function improvements, providing evidence for optimized intervention strategies.

METHODS

A search was conducted using PubMed, Web of Science, The Cochrane Library, and Embase databases for randomized controlled trials related to exercise interventions for neurological dysfunction in diabetic patients. The quality of the included studies was assessed according to the Cochrane Handbook for Systematic Reviews. The study utilized RevMan 5.3 to determine effect sizes and assess heterogeneity. Stata 17.0 was employed to evaluate publication bias in the included studies.

RESULTS

The analysis incorporated 9 randomized controlled trials. The meta-analysis demonstrated that exercise leads to improvements in neurological dysfunction among diabetes patients (SMD = 0.61). Subgroup analysis revealed that an 8-week exercise regimen with moderate intensity was particularly effective in enhancing neurological function (SMD = 1.82, 1.58). Improvements were more pronounced in lower limb nerve conduction velocity (SMD = 0.60), peroneal nerve conduction velocity (SMD = 0.86), and sensory nerve conduction velocity (SMD = 0.59). Patients with a disease duration of 5 years or less showed significant improvement (SMD = 0.62).

CONCLUSION

Exercise effectively improves neurological dysfunction in diabetic patients, with an 8-week, moderate-intensity program showing the greatest benefits, particularly in lower limb and sensory nerve conduction velocity. These findings offer evidence-based guidance for clinical intervention and future research.

REGISTRATION AND PROPOSAL

This study was registered with PROSPEO under No. CRD42024586981; the proposal is available at www.crd.york.ac.uk .

Regulatory effects of curcumin on nitric oxide signaling in the cardiovascular system

The continuously rising prevalence of cardiovascular disease (CVD) globally substantially impacts the economic growth of developing countries. Indeed, one of the leading causes of death worldwide is unfavorable cardiovascular events. Reduced nitric oxide (NO) generation is the pathogenic foundation of endothelial dysfunction, which is regarded as the first stage in the development of a number of CVDs. Nitric oxide exerts an array of biological effects, including vasodilation, the suppression of vascular smooth muscle cell proliferation and the functional control of cardiac cells. Numerous treatment strategies aim to increase NO synthesis or upregulate downstream NO signaling pathways. The major component of Curcuma longa, curcumin, has long been utilized in traditional medicine to treat various illnesses, especially CVDs. Curcumin improves CV function as well as having important pleiotropic effects, such as anti-inflammatory and antioxidant, through its ability to increase the bioavailability of NO and to positively impact NO-related signaling pathways. In this review, we discuss the scientific literature relating to curcumin's positive effects on NO signaling and vascular endothelial function.

Antidiabetic activity of eupafolin through peroxisome proliferator-activated receptor-gamma and PI3K/Akt signaling in Type 2 diabetic rats

Eupafolin is a phyto compound of flavone that exerts anti-inflammatory, antioxidant, and antiproliferative properties. The main purpose of this study is to examine the antidiabetic effect of eupafolin on nicotinamide-streptozotocin (STZ)-induced Type 2 diabetes (T2D) rats. After nicotinamide (120 mg/kg) treatment, STZ (60 mg/kg) was administrated intravenously to induce T2D. Rats with fasting blood glucose (FBG) > 200 mg/dL are chosen for the study 7 days after T2D induction. The eupafolin treatment was continued for another 15 days. FBG and an oral glucose tolerance test (OGTT) were measured on the 21st day after T2D induction. The blood lipid, serum insulin, and homeostatic model assessment (HOMA-IR) were determined. In liver homogenate, oxidative stress indicators were measured. In addition, the effect of eupafolin on the expression of the proteins InsR, insulin receptor substrate (IRS)-2, GLUT4, PPARγ, and phosphatidylinositol 3-kinase (PI3K)/Akt was investigated using a western blot. As measured by OGTT and HOMA-IR, eupafolin treatment reduced FBG and insulin resistance (IR). Furthermore, when compared to diabetic rats, liver antioxidant enzymes were dramatically normalized. The level of glycogen in the liver of diabetic rats was increased by eupafolin treatment. In T2D rats, eupafolin dramatically increased the InsR, IRS-2, GLUT4, and PPARγ. Further, the eupafolin treatment activated the PI3K/Akt signaling in T2D rats. These findings imply that the antidiabetic mechanism of eupafolin may be related to the activation of the PPARγ and the PI3K/Akt signaling pathway in T2D rats. As a result, the flavonoid eupafolin could be an antidiabetic medication for T2D after a comprehensive clinical investigation.

Apolipoprotein H: a novel regulator of fat accumulation in duck myoblasts

Apolipoprotein H (APOH) primarily engages in fat metabolism and inflammatory disease response. This study aimed to investigate the effects of APOH on fat synthesis in duck myoblasts (CS2s) by APOH overexpression and knockdown. CS2s overexpressing APOH showed enhanced triglyceride (TG) and cholesterol (CHOL) contents and elevated the mRNA and protein expression of AKT serine/threonine kinase 1 (AKT1), ELOVL fatty acid elongase 6 (ELOVL6), and acetyl-CoA carboxylase 1 (ACC1) while reducing the expression of protein kinase AMP-activated catalytic subunit alpha 1 (AMPK), peroxisome proliferator activated receptor gamma (PPARG), acyl-CoA synthetase long chain family member 1 (ACSL1), and lipoprotein lipase (LPL). The results showed that knockdown of APOH in CS2s reduced the content of TG and CHOL, reduced the expression of ACC1, ELOVL6, and AKT1, and increased the gene and protein expression of PPARG, LPL, ACSL1, and AMPK. Our results showed that APOH affected lipid deposition in myoblasts by inhibiting fatty acid beta-oxidation and promoting fatty acid biosynthesis by regulating the expression of the AKT/AMPK pathway. This study provides the necessary basic information for the role of APOH in fat accumulation in duck myoblasts for the first time and enables researchers to study the genes related to fat deposition in meat ducks in a new direction.

Puerarin-V prevents the progression of hypoxia- and monocrotaline-induced pulmonary hypertension in rodent models

Pulmonary hypertension (PH) is a cardiopulmonary disease characterized by a progressive increase in pulmonary vascular resistance. One of the initial pathogenic factors of PH is pulmonary arterial remodeling under various stimuli. Current marketed drugs against PH mainly relieve symptoms without significant improvement in overall prognosis. Discovering and developing new therapeutic drugs that interfere with vascular remodeling is in urgent need. Puerarin is an isoflavone compound extracted from the root of Kudzu vine, which is widely used in the treatment of cardiovascular diseases. In the present study, we evaluated the efficacy of puerarin in the treatment of experimental PH. PH was induced in rats by a single injection of MCT (50 mg/kg, sc), and in mice by exposure to hypoxia (10% O2) for 14 days. After MCT injection the rats were administered puerarin (10, 30, 100 mg · kg-1 · d-1, i.g.) for 28 days, whereas hypoxia-treated mice were pre-administered puerarin (60 mg · kg-1 · d-1, i.g.) for 7 days. We showed that puerarin administration exerted significant protective effects in both experimental PH rodent models, evidenced by significantly reduced right ventricular systolic pressure (RVSP) and lung injury, improved pulmonary artery blood flow as well as pulmonary vasodilation and contraction function, inhibited inflammatory responses in lung tissues, improved resistance to apoptosis and abnormal proliferation in lung tissues, attenuated right ventricular injury and remodeling, and maintained normal function of the right ventricle. We revealed that MCT and hypoxia treatment significantly downregulated BMPR2/Smad signaling in the lung tissues and PPARγ/PI3K/Akt signaling in the lung tissues and right ventricles, which were restored by puerarin administration. In addition, we showed that a novel crystal type V (Puer-V) exerted better therapeutic effects than the crude form of puerarin (Puer). Furthermore, Puer-V was more efficient than bosentan (a positive control drug) in alleviating the abnormal structural changes and dysfunction of lung tissues and right ventricles. In conclusion, this study provides experimental evidence for developing Puer-V as a novel therapeutic drug to treat PH.

Drinking Molecular Hydrogen Water Is Beneficial to Cardiovascular Function in Diet-Induced Obesity Mice

Molecular hydrogen (MH) reportedly exerts therapeutic effects against inflammatory diseases as a suppressor of free radical chain reactions. Here, the cardiovascular protective effects of the intake of molecular hydrogen water (MHW) were investigated using high-fat diet-induced obesity (DIO) mice. MHW was prepared using supplier sticks and degassed water as control. MHW intake for 2 weeks did not improve blood sugar or body weight but decreased heart weight in DIO mice. Moreover, MHW intake improved cardiac hypertrophy, shortened the width of cardiomyocytes, dilated the capillaries and arterioles, activated myocardial eNOS-Ser-1177 phosphorylation, and restored left ventricular function in DIO mice. MHW intake promoted the histological conversion of hypertrophy to hyperplasia in white and brown adipose tissues (WAT and BAT) with the upregulation of thermogenic and cardiovascular protective genes in BAT (i.e., Ucp-1, Vegf-a, and eNos). Furthermore, the results of a colony formation assay of bone-marrow-derived endothelial progenitor cells (EPCs) indicated that MHW activated the expansion, differentiation, and mobilization of EPCs to maintain vascular homeostasis. These findings indicate that the intake of MHW exerts cardiovascular protective effects in DIO mice. Hence, drinking MHW is a potential prophylactic strategy against cardiovascular disorders in metabolic syndrome.

Effect of Quercetin on Lipids Metabolism Through Modulating the Gut Microbial and AMPK/PPAR Signaling Pathway in Broilers

The present study was conducted to investigate effects and mechanism of quercetin on lipids metabolism in broilers. 480 AA broilers were randomly allotted to four treatments (0, 0.2, 0.4, and 0.6 g/kg quercetin) for 42 days. Compared with the control, 0.6 g/kg quercetin significantly decreased percentage of abdominal fat (P < 0.05); 0.2, 0.4, and 0.6 g/kg quercetin significantly decreased relative abundance of Lachnospiraceae and Desulfovibrionaceae (P < 0.05, P < 0.05, P < 0.01; P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased mRNA expression of PI3K, AMPKα1, AMPKα2, AMPKβ2, LKB1 (P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05), and significantly reduced mRNA expression of SREBP1 and PPARγ (P < 0.01, P < 0.05); 0.4 g/kg quercetin significantly increased mRNA expression of LKB1 and PKB (P < 0.05, P < 0.01) and significantly reduced mRNA expression of ACC, HMGR, PPARγ, and SREBP1 (P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.6 g/kg quercetin significantly increased mRNA expression of AMPKγ, LKB1, CPT1, PPARα, PKB (P < 0.01, P < 0.01, P < 0.01, P < 0.05, P < 0.05), and significantly reduced the mRNA expression of PI3K, ACC, HMGR, PPARγ, SREBP1 (P < 0.05, P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased protein expression of AMPK (P < 0.01); 0.6 g/kg quercetin significantly increased protein expression of LKB1 (P < 0.01), 0.2 and 0.6 g/kg quercetin significantly increased protein expression of PI3K, PKB, CPT1 (P < 0.05, P < 0.01, P < 0.05, P < 0.01, P < 0.01, P < 0.01), and significantly reduced protein expression of ACC and SREBP1 (P < 0.01, P < 0.01, P < 0.01, P < 0.01). In conclusion, quercetin improved lipid metabolism by modulating gut microbial and AMPK/PPAR signaling pathway in broilers.

Metformin downregulates miR223 expression in insulin-resistant 3T3L1 cells and human diabetic adipose tissue

AIMS AND DESIGNS

Metformin, an anti-diabetic drug, is the first line medication for the treatment of type 2 diabetes mellitus and some studies show its relationship with micro-RNAs. This study set up to determine the effect of metformin on miR223 expression and content of AKT/GLUT4 proteins in insulin resistant signaling in 3T3L1 cells and adipocyte of human diabetic patients.

MATERIALS AND METHODS

Subcutaneous adipose tissues were taken from newly diagnosed diabetic patients (HOMA-IR > 1.8), before and after three months treatment with 500 mg of metformin twice a day. Cellular homogenate was prepared and miR223 expression and AKT/GLUT4 protein expression were determined by quantitative real-time PCR and western blotting. The results were compared to insulin resistant 3T3L1 adipocytes that were treated with 10 mM Metformin.

RESULTS

MiR223 expression was significantly overexpressed both in insulin-resistant 3T3L1 adipocytes compared to non-insulin resistant adipocytes and in human diabetic adipose tissue, compared to non-diabetics (P value < 0.01). Metformin treatment downregulated miR223 expression in both adipocytes and human diabetic adipose tissue. In contrast the IRS/PI3-K/AKT pathway signaling components, Akt and GLUT4 increased in insulin-resistant 3T3L1 adipocytes and human diabetic adipose tissue after three months of metformin treatment.

CONCLUSIONS

Metformin reduced insulin resistance in adipocytes by reduction of miR223 expression and improving of IRS/Akt/GLUT4 signaling pathways. Plasma miR223 expression of human diabetic patients was reduced by metformin treatment. These results point to a novel mechanism of miR223 in insulin resistance.

Isosteviol sodium protects the cardiomyocyte response associated with the SIRT1/PGC-1α pathway

Cardiomyocyte dysfunction is attributed to excess oxidative damage, but the molecular pathways involved in this process have not been completely elucidated. Evidence indicates that isosteviol sodium (STVNa) has cardioprotective effects. We therefore aimed to identify the effect of STVNa on cardiomyocytes, as well as the potential mechanisms involved in this process. We established two myocardial hypertrophy models by treating H9c2 cells with high glucose (HG) and isoprenaline (ISO). Our results showed that STVNa reduced H9c2 mitochondrial damage by attenuating oxidative damage and altering the morphology of mitochondria. The results also indicated that STVNa had a positive effect on HG- and ISO-induced damages via mitochondrial biogenesis. The protective effects of STVNa on cardiomyocytes were associated with the regulation of the SIRT1/PGC-1α signalling pathway. Importantly, the effects of STVNa involved different methods of regulation in the two models, which was confirmed by experiments using an inhibitor and activator of SIRT1. Together, the results provide the basis for using STVNa as a therapy for the prevention of cardiomyocyte dysfunctions.

Jaceosidin Ameliorates Insulin Resistance and Kidney Dysfunction by Enhancing Insulin Receptor Signaling and the Antioxidant Defense System in Type 2 Diabetic Mice

Emerging evidence has shown that flavonoids extracted from Artemisia have beneficial effects on metabolic disorders. However, whether and how jaceosidin ameliorates insulin resistance and diabetic nephropathy in type 2 diabetes mellitus is largely unknown. For 8 weeks, db/db diabetic mice were fed with or without jaceosidin. Oral jaceosidin supplementation reduced fasting blood glucose levels and insulin resistance through the upregulation of insulin receptor downstream pathways in the liver and skeletal muscles. While jaceosidin did not noticeably alter kidney filtration function, this dietary intervention contributed to attenuating the accumulation of advanced glycation end products in diabetic kidneys. The levels of VEGF-a (vascular endothelial growth factor-a) proteins in the diabetic kidneys were markedly diminished by jaceosidin treatments, which increased the expression and activity of Cu (copper) and Zn-SOD (zinc-superoxide dismutase). Therefore, it is suggested that jaceosidin supplementation elicits antidiabetic effects and treats diabetic nephropathy by augmenting insulin signaling, suppressing fibrosis, and enhancing antioxidant activity.

Descending Expression of miR320 in Insulin-Resistant Adipocytes Treated with Ascending Concentrations of Metformin

Some miRNAs are supposed to play a role in insulin resistance and metabolic disorders. Such miRNAs can be differentially expressed in response to a pharmacologic intervention for insulin resistance as a biomarker/risk factor for insulin resistance. This study aimed at determining the effect of Metformin on miR320 expression in insulin-resistant (IR) adipocytes. The 3T3L1 cells were expanded in DMEM, differentiated into adipocytes by differentiating medium, became resistant to insulin, and then were treated with ascending concentrations of Metformin. Quantitative real-time PCR was performed to profile the miR320 expression in 3T3L1 adipocytes, IR adipocytes, and Metformin-treated IR adipocytes. Compared to the normal adipocytes, IR adipocytes exhibited a significantly higher level of miR320 expression, however, in response to Metformin graded concentrations, IR adipocytes down-regulated miR320 and were almost at normal level. The maximum effect of Metformin was at 10 mM. In IR adipocytes, miR320 expression is over-expressed which can be down-regulated by Metformin treatment. The findings provide some information on a potentially new marker to determine insulin resistance and to predict response to insulin resistance therapy.

Protective effects of phenolic acid extract from ginseng on vascular endothelial cell injury induced by palmitate via activation of PI3K/Akt/eNOS pathway

Elevated free fatty acids may impair insulin-mediated signaling to eNOS that contributes to the pathophysiology of endothelial dysfunction. Previous studies have indicated the protective effect of ginseng and the regulatory potential of phenolic acid components from other plants on endothelial function. Therefore, this study investigated the protective effects of phenolic acid extract from ginseng (PG2) on endothelial cells against palmitate-induced damage. We found that PG2 increases cell viability, inhibits the palmitate-induced intracellular accumulation of lipids, and the overexpression of endothelin-1 (ET-1) through enhancing the phosphorylation of the phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling pathway. The results of this study may be valuable for the development of PG2 to combat the endothelial cell damage caused by hyperlipidemia. PRACTICAL APPLICATION: We proved that phenolic acid extract from ginseng has a protective effect on free fatty acid-induced endothelial dysfunction in vitro. This study provides experimental data for the application of ginseng-derived phenolic acids in treating cardiovascular disease.

PPARγ-Independent Side Effects of Thiazolidinediones on Mitochondrial Redox State in Rat Isolated Hearts

The effect of anti-diabetic thiazolidinediones (TZDs) on contributing to heart failure and cardiac ischemia/reperfusion (IR) injury is controversial. In this study we investigated the effect of select TZDs on myocardial and mitochondrial function in Brown Norway rat isolated hearts. In a first set of experiments, the TZD rosiglitazone was given acutely before global myocardial IR, and pre- and post-IR function and infarct size were assessed. In a second set of experiments, different concentrations of rosiglitazone and pioglitazone were administered in the presence or absence of the specific PPARγ antagonist GW9662, and their effects on the mitochondrial redox state were measured by online NADH and FAD autofluorescence. The administration of rosiglitazone did not significantly affect myocardial function except for transiently increasing coronary flow, but it increased IR injury compared to the control hearts. Both TZDs resulted in dose-dependent, reversible increases in mitochondrial oxidation which was not attenuated by GW9662. Taken together, these data suggest that TZDs cause excessive mitochondrial uncoupling by a PPARγ-independent mechanism. Acute rosiglitazone administration before IR was associated with enhanced cardiac injury. If translated clinically, susceptible patients on PPARγ agonists may experience enhanced myocardial IR injury by mitochondrial dysfunction.

Puerarin protects pulmonary arteries from hypoxic injury through the BMPRII and PPARγ signaling pathways in endothelial cells

BACKGROUND

Recent evidence indicates that Puerarin has a protective effect on pulmonary arteries. In the present study, we aimed to investigate whether Puerarin could protect pulmonary arterial endothelial cells from hypoxic injury and determine its potential targets.

METHODS

In our study, human pulmonary arterial endothelial cells (HPAECs) were injured by hypoxic (1% O2) incubation. Cell viability was detected by a cell counting kit (CCK8). The production of nitric oxide (NO) was detected by Griess reagent and endothelin-1 (ET-1) was detected by the ELISA method. Oxidative stress was measured by a fluorescence microscope via the fluorescent probe DCFH-DA. Western blotting was employed for studying the mechanism.

RESULTS

The results show that Puerarin protects HPAECs from hypoxia-induced apoptosis and slightly improves cell viability. Puerarin increases NO and decreases ET-1 to prevent the imbalance between vasoactive substances induced by hypoxia in HPAECs. Puerarin also inhibits the oxidative stress induced by hypoxia. The results from the Western blot show that Puerarin activates the BMPRII/Smad and PPARγ/PI3K/Akt signaling pathways.

CONCLUSION

In conclusion, Puerarin protects HPAECs from hypoxic injury through the inhibition of oxidative stress and the activation of the BMPRII and PPARγ signaling pathways. This work provides insight into the development of Puerarin as a treatment for hypoxic pulmonary hypertension.

Antidiabetic effects of pterostilbene through PI3K/Akt signal pathway in high fat diet and STZ-induced diabetic rats

Pterostilbene (PTE) is a natural dimethylated analog of resveratrol, which exerts antioxidative, hypolipidemic and hypoglycemic effects; however, the underlying mechanism is not yet clear. In this study, we evaluated the effects of PTE on diabetic rats and clarified the underlying mechanism. Diabetes was induced in rats by streptozotocin (STZ) and a high-sugar and high-fat diet. Rats were then treated with PTE (20, 40 and 80 mg/kg/d) for 8 weeks. Oral glucose tolerance test (OGTT) was performed to measure the glycometabolism of the diabetic rats at the end of the treatment. Fasting blood glucose (FBG), fasting insulin (FINS) and lipid profile were determined using an automatic biochemistry analyzer and serum inflammatory factors were analyzed by enzyme-linked immunosorbent assay. Serum superoxide dismutase (SOD) and malondialdehyde (MDA) were also analyzed by spectrophotometry to evaluate the anti-oxidant effects. The expression of proteins of PPARγ and PI3K/Akt signaling pathway related proteins in adipose tissue of the diabetic rats was analyzed by Western blotting. PTE treatment significantly reduced weight loss, FBG, insulin resistance, serum lipid levels and inflammatory factors. PTE treatment also inhibited oxidative stress by decreasing MDA expression and increasing SOD expression. Simultaneously, PTE treatment significantly ameliorated morphological impairment of the pancreas in diabetic rats. Furthermore, PTE treatment significantly increased the protein expression of PPARγ, PI3K, p-Akt, GLUT4 and IRS-1 in adipose tissues of diabetic rats. This study suggests that PTE can exert antidiabetic effects via the PI3K/Akt signaling pathway.

Resistin up-regulates LPL expression through the PPARγ-dependent PI3K/AKT signaling pathway impacting lipid accumulation in RAW264.7 macrophages

Resistin is a cysteine-rich cytokine, which has been indicated as a mediator of insulin resistance and inflammation. Previous studies demonstrated that lipoprotein lipase (LPL) was an important enzyme that could mediate lipid accumulation in macrophages. Additionally, the intracellular molecules phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT)/peroxisome proliferator-activated receptor (PPARγ) were supposed to be involved in the lipid accumulation process in cells. However, it remains unclear whether resistin was correlated with the dysregulation of lipid metabolism in macrophages. The present study investigated that resistin could up-regulate the expression of LPL and increase the contents of intracellular triglyceride (TG) and total cholesterol (TC) in RAW264.7 macrophages. In addition, intracellular molecules PI3K, AKT and PPARγ were significantly up-regulated and activated in resitin-stimulated RAW264.7 macrophages (P < 0.05). In contrast, the effects of resistin on RAW264.7 macrophages could be abrogated by specific inhibitors for LPL (LPL-siRNA) and PI3K/AKT signaling pathway (LY294002). All together, this study demonstrated that resistin could up-regulate the expression of LPL and induce lipid accumulation in RAW264.7 macrophages. More importantly, the PPARγ-dependent PI3K/AKT signaling pathway was relevant to the lipid accumulation process in resistin-stimulated macrophages.

Hydromorphine postconditioning protects isolated rat heart against ischemia-reperfusion injury via activating P13K/Akt/eNOS signaling

INTRODUCTION

Myocardial ischemia/reperfusion injury (myocardial I/R injury) has a high disability rate and mortality. Novel treatments for myocardial I/R injury are necessary.

AIM

In order to explore the protective effect of hydromorphine on myocardial I/R injury, we illuminate the underlying mechanism of the protective effect.

RESULTS

Hydromorphine significantly reduced myocardial infarct size (IFN/AAR), CKMB (Creatine Kinase MB) and TN-T (Troponin T) release, and improved cardiac function compared with I/R group. However, these advantageous effects were partly suppressed in the presence of hydromorphine. Myocardial I/R injury significantly decreased the phosphorylation of Akt and eNOS, and down-regulated total nitric oxide and nitrotyrosine content, while these inhibitory effects were partly abolished by hydromorphine. Conversely, the activated effects of hydromorphine on the phosphorylation of Akt and eNOS, and NO release were totally reversed by LY294002, which, used individually, show the same influence on reperfusion injury.

CONCLUSIONS

These findings suggest that hydromorphine postconditioning may protect isolated rat heart against reperfusion injury via activating P13K/Akt/eNOS signaling.

Alterations in NO/ROS ratio and expression of Trx1 and Prdx2 in isoproterenol-induced cardiac hypertrophy

The development of cardiac hypertrophy is a complicated process, which undergoes a transition from compensatory hypertrophy to heart failure, and the identification of new biomarkers and targets for this disease is greatly needed. Here we investigated the development of isoproterenol (ISO)-induced cardiac hypertrophy in an in vitro experimental model. After the induction of hypertrophy with ISO treatment in H9c2 cells, cell surface area, cell viability, cellular reactive oxygen species (ROS), and nitric oxide (NO) levels were tested. Our data showed that the cell viability, mitochondrial membrane potential, and NO/ROS balance varied during the development of cardiac hypertrophy in H9c2 cells. It was also found that the expression of thioredoxin1 (Trx1) and peroxiredoxin2 (Prdx2) was decreased during the cardiac hypertrophy of H9c2 cells. These results suggest a critical role for Trx1 and Prdx2 in the cardiac hypertrophy of H9c2 cells and in the transition from compensated hypertrophy to de-compensated hypertrophy in H9c2 cells, and our findings may have important implications for the management of this disease.

Exosomes: A Rising Star in Falling Hearts

Although exosomes were previously recognized as a mechanism for discharging useless cellular components, growing evidence has elucidated their roles in conveying information between cells. They contribute to cell-cell communication by carrying nucleic acids, proteins and lipids that can, in turn, regulate behavior of the target cells. Recent research suggested that exosomes extensively participate in progression of diverse cardiovascular diseases (CVDs), such as myocardial infarction, cardiomyopathy, pulmonary arterial hypertension and others. Here, we summarize effects of exosome-derived molecules (mainly microRNAs and proteins) on cardiac function, to examine their potential applications as biomarkers or therapeutics in CVDs.

Insulin and β Adrenergic Receptor Signaling: Crosstalk in Heart

Recent advances show that insulin may affect β adrenergic receptor (βAR) signaling in the heart to modulate cardiac function in clinically relevant states, such as diabetes mellitus (DM) and heart failure (HF). Conversely, activation of βAR regulates cardiac glucose uptake and promotes insulin resistance (IR) in HF. Here, we discuss the recent characterization of the interaction between the cardiac insulin receptor (InsR) and βAR in the myocardium, in which insulin stimulation crosstalks with cardiac βAR via InsR substrate (IRS)-dependent and G-protein receptor kinase 2 (GRK2)-mediated phosphorylation of β₂AR. The insulin-induced phosphorylation promotes β₂AR coupling to G_i and expression of phosphodiesterase 4D, which both inhibit cardiac adrenergic signaling and compromise cardiac contractile function. These recent developments could support new approaches for the effective prevention or treatment of obesity- or DM-related HF.

Exogenous cathepsin V protein protects human cardiomyocytes HCM from angiotensin Ⅱ-Induced hypertrophy

Angiotensin (Ang) Ⅱ-induced cardiac hypertrophy can deteriorate to heart failure, a leading cause of mortality. Endogenous Cathepsin V (CTSV) has been reported to be cardioprotective against hypertrophy. However, little is known about the effect of exogenous CTSV on cardiac hypertrophy. We used the human cardiomyocytes HCM as a cell model to investigate the effects of exogenous CTSV on Ang Ⅱ-induced cardiac cell hypertrophy. Cell surface area and expression of classical markers of hypertrophy were analyzed. We further explored the mechanism of CTSV cardioprotective by assessing the levels and activities of PI3K/Akt/mTOR and MAPK signaling pathway proteins. We found that pre-treating cardiomyocytes with CTSV could significantly inhibit Ang Ⅱ-induced hypertrophy. The mRNA expression of hypertrophy markers ANP, BNP and β-MHC was obviously elevated in Ang Ⅱ-treated cardiac cells. Whereas, exogenous CTSV effectively halted this elevation. Further study revealed that the protective effects of exogenous CTSV might be mediated by repressing the phosphorylation of proteins in the PI3K/Akt/mTOR and MAPK pathways. Based on our results, we concluded that exogenous CTSV inhibited Ang Ⅱ-induced hypertrophy in HCM cells by inhibiting PI3K/Akt/mTOR. This study provides experimental evidence for the application of CTSV protein for the treatment of cardiac hypertrophy.

Macro- and microvascular endothelial dysfunction in diabetes

Endothelial cells, as well as their major products nitric oxide (NO) and prostacyclin, play a key role in the regulation of vascular homeostasis. Diabetes mellitus is an important risk factor for cardiovascular disease. Diabetes-induced endothelial dysfunction is a critical and initiating factor in the genesis of diabetic vascular complications. The present review focuses on both large blood vessels and the microvasculature. The endothelial dysfunction in diabetic macrovascular complications is characterized by reduced NO bioavailability, poorly compensated for by increased production of prostacyclin and/or endothelium-dependent hyperpolarizations, and increased production or action of endothelium-derived vasoconstrictors. The endothelial dysfunction of microvascular complications is primarily characterized by decreased release of NO, enhanced oxidative stress, increased production of inflammatory factors, abnormal angiogenesis, and impaired endothelial repair. In addition, non-coding RNAs (microRNAs) have emerged as participating in numerous cellular processes. Thus, this reviews pays special attention to microRNAs and their modulatory role in diabetes-induced vascular dysfunction. Some therapeutic strategies for preventing and restoring diabetic endothelial dysfunction are also highlighted.

Danhong injection attenuates isoproterenol-induced cardiac hypertrophy by regulating p38 and NF-κb pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Danhong injection (DHI), derived from Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Salvia militiorrhiza Bunge), is an extensively-used Chinese material standardized clinical product for treatment of cardiovascular diseases.

AIM OF THE STUDY

Cardiac hypertrophy (CH) is an adaptive response of cardiomyocytes. Long-lasting cardiac hypertrophy results in the loss of compensation by cardiomyocytes which could ultimately develop into heart failure. In the present study, we aimed to investigate the effect and exact mechanisms of DHI on isoproterenol (ISO)-induced CH.

MATERIALS AND METHODS

H9c2 cells and male Wistar rats were stimulated by ISO in the present study to establish CH models in vitro and in vivo. CCk-8 assay, Western blot, real time-polymerase chain reaction (RT-PCR), electrophoretic mobility shift assay (EMSA) and Echocardiography were used in the present study.

RESULTS

DHI significantly attenuated ISO-induced CH of H9c2 cells (p<0.01). DHI decreased ISO-induced atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) elevation both at the mRNA and protein levels (p<0.05 and p<0.01, respectively). Western blot showed that DHI down-regulated the phosphorylation of p38. Furthermore, we found that DHI inhibited the nuclear translocation and activation of NF-κb. Echocardiography from ISO-induced CH rats showed that DHI significantly decreased left ventricle (LV) mass, the thickness of the LV end-systolic posterior wall (LVPWs), and the LV end-diastolic posterior wall (LVPWd) elevated by ISO (p<0.01 and p<0.05, respectively).

CONCLUSION

These data demonstrate that DHI might exert anti-cardiac hypertrophic effects by regulating p38 and NF-κb pathway.

Role of eNOS- and NOX-containing microparticles in endothelial dysfunction in patients with obesity

OBJECTIVE

To explore the pathophysiological profile of patients who have obesity and to investigate the potential role of circulating microparticles (MPs) in endothelial dysfunction in patients who have obesity.

METHODS

The inflammatory and oxidative status and the cutaneous microvascular blood flow were characterized in 69 patients with android obesity and 46 subjects with normal weight (controls) by using laser Doppler flowmetry. Circulating MP levels were measured by flow cytometry, and endothelial nitric oxide synthase (eNOS) and NADPH oxidase (NOX) expression in MPs was investigated by Western blotting. MP effect on vascular reactivity was assessed in rat aorta rings.

RESULTS

Patients with obesity showed endothelial dysfunction, hyperglycemia, inflammation, and oxidative stress. In controls, low MP levels were positively correlated with normal microvascular function. Western blot analysis revealed reduced eNOS and increased NOX4D expression in MPs from subjects with obesity compared with controls. However, this was not correlated with endothelial dysfunction parameters and did not impair ex vivo endothelium-dependent vasodilation.

CONCLUSIONS

These results suggest that MPs do not contribute directly to endothelial dysfunction associated with obesity. Conversely, eNOS- and NOX-containing MPs could be involved in the compensatory mechanism of vascular endothelial cells to counteract the pathologic mechanisms underlying endothelial dysfunction.

Methylophiopogonanone A suppresses ischemia/reperfusion-induced myocardial apoptosis in mice via activating PI3K/Akt/eNOS signaling pathway

AIM

The dried tuber root of Ophiopogon japonicus has been used in the traditional Chinese medicine for treatment of myocardial ischemia and thrombosis. In this study we investigated the effects of methylophiopogonanone A (MO-A), a major homoisoflavonoid in Ophiopogon japonicus, on myocardial ischemia/reperfusion (I/R) injury.

METHODS

Mice were pretreated with MO-A (10 mg·kg(-1)·d(-1), po) for 2 weeks and then subjected to transient occlusion of the left anterior descending coronary artery. Cardiac function was evaluated, and the infarct size and apoptosis index were assessed. The mechanisms underlying the cardio-protection of MO-A were analyzed in H9C2 rat cardiomyocytes subjected to hypoxia/reoxygenation (H/R). The cell viability and apoptosis were evaluated; apoptotic and relevant signaling proteins were analyzed. NO levels in the culture medium were assessed.

RESULTS

In I/R mice, pretreatment with MO-A significantly reduced the infarct size (by 60.7%) and myocardial apoptosis (by 56.8%), and improved cardiac function. In H9C2 cells subjected to H/R, pretreatment with MO-A (10 μmol/L) significantly decreased apoptosis and cleaved caspase-3 expression, elevated the Bcl-2/Bax ratio and restored NO production. Furthermore, pretreatment with MO-A markedly increased the activation of PI3K/Akt/eNOS pathway in H9C2 cells subjected to H/R, and the protective effects of MO-A were abolished in the presence of the PI3K inhibitor wortmannin (100 nmol/L).

CONCLUSION

MO-A attenuates I/R-induced myocardial apoptosis in mice via activating the PI3K/Akt/eNOS signaling pathway.

Schisandra polysaccharide increased glucose consumption by up-regulating the expression of GLUT-4

In our previous study, a polysaccharide was extracted from Schisandra Chinensis (Trucz.) Baill and found with anti-diabetic effects. The aim of this study was to investigate the anti-diabetic effects of the low weight molecular polysaccharide (SCPP11) purified from crude Schisandra polysaccharide and illustrate the underlying mechanism in buffalo rat liver cells. The insulin resistance model of BRL cells was established by incubating with insulin solution for 24h. The effects of SCPP11 on regulating related protein and mRNA expression in an insulin and AMPK signal pathway were investigated by western blot and RT-PCR analysis. SCPP11 showed no cytotoxicity to BRL cells and could improve the glucose consumption in BRL cells. SCPP11 increased the protein expression of Akt, p-AMPK and GLUT-4 in BRL cells. Moreover, SCPP11 could enhance the mRNA expression levels of IRS-1, PI3K, Akt, GLUT-4, AMPKα and PPAR-γ in BRL cells at the same time. In conclusion, SCPP11 possessed effects in improving glucose consumption by up-regulating the expression of GLUT-4 which might occur via insulin and AMPK signal pathway and could be a potential functional food to prevent and mitigate the insulin resistance condition.