The critical role of Astragalus polysaccharides for the improvement of PPARα [ correction of PPRAα]-mediated lipotoxicity in diabetic cardiomyopathy

Fatty acid metabolism disorders and potential therapeutic traditional Chinese medicines in cardiovascular diseases

Cardiovascular diseases are currently the primary cause of mortality in the whole world. Growing evidence indicated that the disturbances in cardiac fatty acid metabolism are crucial contributors in the development of cardiovascular diseases. The abnormal cardiac fatty acid metabolism usually leads to energy deficit, oxidative stress, excessive apoptosis, and inflammation. Targeting fatty acid metabolism has been regarded as a novel approach to the treatment of cardiovascular diseases. However, there are currently no specific drugs that regulate fatty acid metabolism to treat cardiovascular diseases. Many traditional Chinese medicines have been widely used to treat cardiovascular diseases in clinics. And modern studies have shown that they exert a cardioprotective effect by regulating the expression of key proteins involved in fatty acid metabolism, such as peroxisome proliferator-activated receptor α and carnitine palmitoyl transferase 1. Hence, we systematically reviewed the relationship between fatty acid metabolism disorders and four types of cardiovascular diseases including heart failure, coronary artery disease, cardiac hypertrophy, and diabetic cardiomyopathy. In addition, 18 extracts and eight monomer components from traditional Chinese medicines showed cardioprotective effects by restoring cardiac fatty acid metabolism. This work aims to provide a reference for the finding of novel cardioprotective agents targeting fatty acid metabolism.

The role of circadian clock-controlled mitochondrial dynamics in diabetic cardiomyopathy

Diabetes mellitus is a metabolic disease with a high prevalence worldwide, and cardiovascular complications are the leading cause of mortality in patients with diabetes. Diabetic cardiomyopathy (DCM), which is prone to heart failure with preserved ejection fraction, is defined as a cardiac dysfunction without conventional cardiac risk factors such as coronary heart disease and hypertension. Mitochondria are the centers of energy metabolism that are very important for maintaining the function of the heart. They are highly dynamic in response to environmental changes through mitochondrial dynamics. The disruption of mitochondrial dynamics is closely related to the occurrence and development of DCM. Mitochondrial dynamics are controlled by circadian clock and show oscillation rhythm. This rhythm enables mitochondria to respond to changing energy demands in different environments, but it is disordered in diabetes. In this review, we summarize the significant role of circadian clock-controlled mitochondrial dynamics in the etiology of DCM and hope to play a certain enlightening role in the treatment of DCM.

Astragalus polysaccharides alleviates cardiac hypertrophy in diabetic cardiomyopathy via inhibiting the BMP10-mediated signaling pathway

BACKGROUND

Cardiac hypertrophy can lead to cardiac dysfunction and is closely associated with mortality in diabetic cardiomyopathy (DCM). Astragalus polysaccharides (APS) is the main component extracted from Astragalus membranaceus (Fisch.) Bunge (AM), which exhibits anti-hypertrophic effects on cardiomyocytes in various diseases. However, whether APS exerts anti-hypertrophic effects in DCM remains unclear.

PURPOSE

To investigate whether APS can attenuate cardiac hypertrophy in DCM and exert anti-hypertrophic effects by inhibiting the bone morphogenetic protein 10 (BMP10) pathway.

METHODS

The anti-hypertrophic effects of APS were studied in high-glucose (HG)-stimulated H9c2 cardiomyocytes and streptozotocin (STZ)-induced DCM rats. BMP10 siRNA was used to inhibit BMP10 expression in H9c2 cardiomyocytes. Cardiac function was assessed by echocardiography. Cardiac hypertrophy was evaluated using heart weight/body weight (HW/BW), RT-PCR, hematoxylin-eosin (HE), and rhodamine phalloidin staining. Changes in hypertrophic components, including BMP10 and downstream factors, were measured using western blotting.

RESULTS

In vitro, HG treatment increased the relative cell surface area of H9c2 cardiomyocytes, whereas BMP10 siRNA transfection or APS treatment alleviated the increase induced by HG. APS treatment improved the general condition, increased cardiac function, and decreased the HW/BW ratio, ANP mRNA level, and cardiomyocyte cross-sectional area of DCM rats in vivo. Molecular experiments demonstrated that APS downregulated the levels of the pro-hypertrophic protein BMP10 and its downstream proteins ALK3, BMPRII, and p-Smad1/5/8 without affecting the level of total Smad1/5/8.

CONCLUSIONS

Our study demonstrates that APS can alleviate cardiac hypertrophy and protect against DCM by inhibiting activation of the BMP10 pathway. APS is a promising candidate for DCM treatment.

Phytochemistry and cardiovascular protective effects of Huang-Qi (Astragali Radix)

Huang-Qi (Astragali Radix) is an herbal tonic widely used in China and many other countries. It is derived from the roots of Astragalus membranaceus and A. membranaceus var. mongholicus and shows potent cardiovascular protective effects. In this article, we comprehensively reviewed 189 small molecules isolated from the two Astragalus species and discussed the interspecies chemical differences. Moreover, we summarized the pharmacological activities and mechanisms of action of Huang-Qi and its major bioactive compounds for the treatment of cardiovascular diseases. This review covers 171 references published between February 1983 and March 2020.

Beneficial Effects of Echinacoside on Diabetic Cardiomyopathy in Diabetic Db/Db Mice

Purpose

In this study, we investigated the protective effects and mechanism of action of echinacoside (ECH) from cistanche tubulosa extract in cardiomyocytes of db/db diabetic mice.

Methods

Twenty healthy male db/db mice aged 8 weeks were randomly divided into db/db+ECH (n=10, ECH, 300 mg/(kg/d)), db/db (n=10, saline), and db/m control groups (n=9). Mice were monitored weekly for diet and activity. Mice were injected with 2% of pentobarbital sodium in week 10 and executed. Weight and free blood glucose (FBG) were measured weekly. Echocardiographs were used to detect cardiac function. HE staining, Sudan II staining, Masson’s trichrome staining and Tunel assays were used to evaluate myocardial tissue pathological changes, collagen fiber deposition, lipid accumulation and apoptosis rates in cardiomyocytes, respectively. Western blot and RT-PCR analysis were used to detect the expression of components of the PPAR-α/M-CPT-1 and p53/p38MAPK signaling axis.

Results

Compared to db/db mice, ECH groups showed lower blood glucose and lipid levels. Deterioration in cardiac function was also delayed following ECH treatment. Histopathological analysis showed that ECH significantly improved myocardial tissue in db/db mice, including reduced intercellular spaces, regular arrangements, improved extracellular matrix deposition, and reduced lipid accumulation. ECH also significantly reduced oxidative stress levels in myocardial tissue in db/db mice. Moreover, ECH inhibited PPAR-α/M-CPT-1 signaling, downregulated CD36, and upregulated glucose transporter type 4 (GLUT-4) expression in db/db mouse models of DCM. ECH also inhibited p53/p38MAPK signaling, downregulated caspase-3 and caspase-8, and upregulated Bcl-2/Bax in db/db mouse models of DCM.

Conclusion

ECH displays protective effects in DCM, including the inhibition of cardiac apoptosis and oxidative stress, and improved lipid metabolism in cardiomyocytes. ECH also inhibits cardiac apoptosis through its regulation of p53/p38MAPK signaling, and prevents lipid accumulation through suppression of the PPAR-α/M-CPT-1 signaling axis.

Network Pharmacology-Based Identification of the Mechanisms of Shen-Qi Compound Formula in Treating Diabetes Mellitus

Aim

The purpose of this research is to identify the mechanisms of Shen-Qi compound formula (SQC), a traditional Chinese medicine (TCM), for treating diabetes mellitus (DM) using system pharmacology.

Methods

The active components and therapeutic targets were identified, and these targets were analyzed using gene ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein-protein interaction (PPI) analysis. Finally, an integrated pathway was constructed to show the mechanisms of SQC.

Results

A total of 282 active components and 195 targets were identified through a database search. The component-target network was constructed, and the key components were screened out according to their degree. Through the GO, PPI, and KEGG analyses, the mechanism network of SQC treating DM was constructed.

Conclusions

This study shows that the mechanisms of SQC treating DM are related to various pathways and targets. This study provides a good foundation and basis for further in-depth verification and clinical application.

A Systematic Review of Phytochemistry, Pharmacology and Pharmacokinetics on Astragali Radix: Implications for Astragali Radix as a Personalized Medicine

Astragali radix (AR) is one of the most widely used traditional Chinese herbal medicines. Modern pharmacological studies and clinical practices indicate that AR possesses various biological functions, including potent immunomodulation, antioxidant, anti-inflammation and antitumor activities. To date, more than 200 chemical constituents have been isolated and identified from AR. Among them, isoflavonoids, saponins and polysaccharides are the three main types of beneficial compounds responsible for its pharmacological activities and therapeutic efficacy. After ingestion of AR, the metabolism and biotransformation of the bioactive compounds were extensive in vivo. The isoflavonoids and saponins and their metabolites are the major type of constituents absorbed in plasma. The bioavailability barrier (BB), which is mainly composed of efflux transporters and conjugating enzymes, is expected to have a significant impact on the bioavailability of AR. This review summarizes studies on the phytochemistry, pharmacology and pharmacokinetics on AR. Additionally, the use of AR as a personalized medicine based on the BB is also discussed, which may provide beneficial information to achieve a better and more accurate therapeutic response of AR in clinical practice.

Effect of Astragalus Polysaccharides on Cardiac Dysfunction in db/db Mice with Respect to Oxidant Stress

OBJECTIVE

Oxidant stress plays an important role in the development of diabetic cardiomyopathy. Previously we reported that Astragalus polysaccharides (APS) rescued heart dysfunction and cardinal pathological abnormalities in diabetic mice. In the current study, we determined whether the effect of APS on diabetic cardiomyopathy was associated with its impact on oxidant stress.

METHODS

Db/db diabetic mice were employed and administered with APS. The hematodynamics, cardiac ultra-structure, apoptosis, and ROS formation of myocardium were assessed. The cardiac protein expression of apoptosis target genes (Bax, Bcl-2, and caspase-3) and oxidation target genes (Gpx, SOD2, t/p-JNK, catalase, t/p-p38 MAPK, and t/p-ERK) were evaluated, respectively.

RESULTS

APS therapy improved hematodynamics and cardinal ultra-structure with reduced apoptosis and ROS formation in db/db hearts. In addition, APS therapy inhibited the protein expression of apoptosis target genes (Bax, Bcl-2, and caspase-3) and regulated the protein expression of oxidation target genes (enhancing Gpx, SOD2, and catalase, while reducing t/p-JNK, t/p-ERK, and t/p-p38 MAPK) in db/db hearts.

CONCLUSION

Our findings suggest that APS has benefits in diabetic cardiomyopathy, which may be partly associated with its impact on cardiac oxidant stress.

Astragalus polysaccharides inhibits cell growth and pro-inflammatory response in IL-1β-stimulated fibroblast-like synoviocytes by enhancement of autophagy via PI3K/AKT/mTOR inhibition

The hyperplastic growth of rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs) and inflammatory response are pathological hallmarks of RA. It has been reported that Astragalus polysaccharides (APS) possess appreciable anti-inflammatory activity against adjuvant-induced arthritis. Nevertheless, little is known about the role and detailed mechanism underlying the therapeutic effects of APS in RA. This study demonstrated that administration of APS dose-dependently impaired cell viability, increased cell apoptosis by decreasing Bcl-2 expression, increasing Bax expression and Caspase3 activity in IL-1β-stimulated RSC-364 cells and RA-FLS. Simultaneously, IL-1β-induced production of pro-inflammatory cytokines IL-6 and TNF-α was significantly decreased after APS treatment. Furthermore, preconditioning with APS dramatically enhanced autophagy activity by increasing Beclin-1 and LC3II/LC3I expression coupled with decreasing p62 expression and augmenting the number of LC3 puncta in IL-1β-stimulated RSC-364 cells. More importantly, autophagy inhibitor 3-methyladenine (3-MA) partly abolished APS-triggered inhibitory effects on cell growth and production of pro-inflammatory cytokines. APS also repressed the activation of PI3K/Akt/mTOR signaling pathway in IL-1β-stimulated RSC-364 cells. Moreover, treatment with insulin-like growth factor-1 (IGF-1), an activator of PI3K/Akt signaling, partly reversed the therapeutic effects of APS in IL-1β-stimulated RSC-364 cells. Collectively, we concluded that APS might attenuate the pathological progression of RA by exerting the pro-apoptotic and anti-inflammatory effects in IL-1β-stimulated FLSs by regulating the PI3K/AKT/mTOR-autophagy pathway.

Astragalus polysaccharides protect cardiac stem and progenitor cells by the inhibition of oxidative stress-mediated apoptosis in diabetic hearts

Introduction

Diabetic cardiomyopathy is characterized by an imbalance between myocyte death and regeneration mediated by the progressive loss of cardiac stem and progenitor cells (CSPCs) by apoptosis and necrosis due to the activation of oxidative stress with diabetes. In this study, we evaluated the beneficial effect of astragalus polysaccharides (APS) therapy on the protection of CSPCs through its antioxidative capacity in diabetic hearts.

Materials and methods

Streptozotocin (STZ)-induced diabetic mice and heterozygous (SOD2+/−) knockout mice were employed and administered with APS. Ventricular CSPCs were isolated for oxidative evaluation. The abundance, apoptosis and proliferation, reactive oxygen species (ROS) formation, oxidative damage, and SOD2 protein levels and activities were evaluated in ventricular CSPCs.

Results

We confirmed that APS increased the CSPC abundance, reduced the apoptosis of CSPCs, and enhanced the proliferation of CSPCs in both STZ-induced diabetic mice and nondiabetic SOD2+/− mice. In addition, therapy of APS enhanced SOD2 protein levels and enzyme activities, and inhibited ROS formation and oxidative damage of CSPCs from both STZ-induced diabetic mice and nondiabetic SOD2+/− mice.

Conclusion

Our findings demonstrated the positive effect of APS on the rescue of CSPC preservation in diabetes, dependent on the inhibition of oxidative stress-mediated apoptosis.

Astraglaus polysaccharide protects diabetic cardiomyopathy by activating NRG1/ErbB pathway

Diabetic cardiomyopathy (DCM) is one of the main cardiac complications among diabetic patients. According to previous studies, the pathogenesis of DCM is associated with oxidative stress, apoptosis and proliferation of local cardiac cells. It showed, NRG1 can improve the function of mitochondria, and thereby, increasing proliferation and decreasing apoptosis of cardiac muscle cell via ErbB/AKT signaling, also, exert antioxidative function. Besides, NRG1/ErbB pathway was impaired in the DCM model which suggested this signaling played key role in DCM. Astraglaus polysaccharide (APS), one of the active components of Astragalus mongholicus, showed striking antioxidative effect. Here, in this study, our data showed that APS can promote proliferation and decrease apoptosis in AGE-induced DCM cell model, besides, APS can decrease intracellular ROS level, increase activity of SOD, GSH-Px and lower level of MDA and NO in DCM cell model, indicating APS exerted antioxidative function in DCM model cells. Besides, western blot results revealed APS induced NRG1 expressing and the phosphorylation level of ErbB2/4. In addition, the elevated NRG1 promoted AKT and PI3k phosphorylation which indicated APS may exert its function by NRG1/ErbB and the downstream AKT/PI3K signaling. Canertinib is ErbB inhibitor. The effect of APS on proliferation, apoptosis, antioxidation and NRG1/ErbB pathway was partly abolished after the cells were co-treated with APS and canertinib. Taken together, these results suggested APS may display its protective function in DCM cells by activating NGR1/ErbB signaling pathway. And our study increased potential for prevention and therapy to DCM.

Effect of Gegen Qinlian Decoction on Cardiac Gene Expression in Diabetic Mice

The aim of this research is to investigate the therapeutic effect of GGQL decoction on cardiac dysfunction and elucidate the pharmacological mechanisms. db/db mice were divided into DB group or GGQL group, and WT mice were used as control. All mice were accessed by echocardiography. And the total RNA of LV tissue samples was sequenced, then differential expression genes were analyzed. The RNA-seq results were validated by the results of RT-qPCR of 4 genes identified as differentially expressed. The content of pyruvate and ceramide in myocardial tissue was also measured. The results showed that GGQL decoction could significantly improve the diastolic dysfunction, increase the content of pyruvate, and had the trend to reduce the ceramide content. The results of RNA-seq showed that 2958 genes were differentially expressed when comparing the DB group with the WT group. Among them, compared with the DB group, 26 genes were differentially regulated in the GGQL group. The expression results of 4 genes were consistent with the RNA-seq results. Our study reveals that GGQL decoction has a therapeutic effect on diastolic dysfunction of the left ventricular and the effect may be related to its role in promoting myocardial glycolysis and decreasing the content of ceramide.

Astragalus polysaccharides improve cardiomyopathy in STZ-induced diabetic mice and heterozygous (SOD2+/-) knockout mice

Oxidative stress plays an important role in the development of diabetic cardiomyopathy. In the present study, we determined whether the effect of astragalus polysaccharides (APS) on diabetic cardiomyopathy was associated with its impact on oxidative stress. Streptozotocin (STZ)-induced diabetic mice and heterozygous superoxide dismutase (SOD2+/-) knockout mice were administered APS. The hemodynamics, cardiac ultrastructure, and the apoptosis, necrosis and proliferation of cardiomyocytes were assessed to evaluate the effect of APS on diabetic and oxidative cardiomyopathy. Furthermore, H₂O₂ formation, oxidative stress/damage, and SOD activity in cardiomyocytes were evaluated to determine the effects of APS on cardiac oxidative stress. APS therapy improved hemodynamics and myocardial ultrastructure with reduced apoptosis/necrosis, and enhanced proliferation in cardiomyocytes from both STZ-induced diabetic mice and heterozygous SOD2+/- knockout mice. In addition, APS therapy reduced H₂O₂ formation and oxidative stress/damage, and enhanced SOD activity in both groups of mice. Our findings suggest that APS had benefits in diabetic cardiomyopathy, which may be partly associated with its impact on cardiac oxidative stress.

Astragalus polysaccharides attenuates TNF-α-induced insulin resistance via suppression of miR-721 and activation of PPAR-γ and PI3K/AKT in 3T3-L1 adipocytes

Insulin resistance is associated with obesity and type 2 diabetes. The aim of this study was to explore the mechanism of how Astragalus Polysaccharides (APS) improves insulin resistance in 3T3-L1 adipocytes. A cell culture model of insulin resistance was established in mature 3T3-L1 adipocytes by treating them with TNF-α, high glucose and insulin. Glucose uptake levels were detected in each group. To determine the mechanism by which APS improves insulin resistance in 3T3-L1 adipocytes, qRT-PCR was used to detect the expression of miR-721, and Western blots were used to detect the expression or activity of PPAR-γ, PAKT, PI3K, AKT, and GLUT4. Immunostaining was used to detect the expression of GLUT4. We successfully madea model of insulin resistance in mature 3T3-L1 adipocytes. APS increased glucose uptake levels in insulin-resistant adipocytes in a dose- and time-dependent manner, and also increased insulin sensitivity. APS suppressed miR-721 with its target gene PPAR-γ in a dose-dependent manner. miR-721 or PPAR inhibitor T0070907 inhibited the expressions of PPAR-γ, pAKT, and GLUT4 and also reduced glucose accumulation. APS attenuated these miR-721- and PPAR-γ-induced changes. APS increased insulin sensitivity by attenuating the effects of miR-721. The PI3K inhibitor wortmannin reduced the APS-increased pAKT, glucose uptake, and GLUT4 levels, and also reduced those levels in the presence of insulin with or without APS. Taken together, our findings suggest that APS promotes glucose uptake and increases insulin sensitivity in 3T3-L1 adipocytes and may involve the miR-721-PPAR-γ-PI3K/AKT-GLUT4 signaling pathway. These might be new therapeutic targets for treating insulin resistance in obesity and diabetes.

Toll-like receptor 4-related immunostimulatory polysaccharides: Primary structure, activity relationships, and possible interaction models

Toll-like receptor (TLR) 4 is an important polysaccharide receptor; however, the relationships between the structures and biological activities of TLR4 and polysaccharides remain unknown. Many recent findings have revealed the primary structure of TLR4/MD-2-related polysaccharides, and several three-dimensional structure models of polysaccharide-binding proteins have been reported; and these models provide insights into the mechanisms through which polysaccharides interact with TLR4. In this review, we first discuss the origins of polysaccharides related to TLR4, including polysaccharides from higher plants, fungi, bacteria, algae, and animals. We then briefly describe the glucosidic bond types of TLR4-related heteroglycans and homoglycans and describe the typical molecular weights of TLR4-related polysaccharides. The primary structures and activity relationships of polysaccharides with TLR4/MD-2 are also discussed. Finally, based on the existing interaction models of LPS with TLR4/MD-2 and linear polysaccharides with proteins, we provide insights into the possible interaction models of polysaccharide ligands with TLR4/MD-2. To our knowledge, this review is the first to summarize the primary structures and activity relationships of TLR4-related polysaccharides and the possible mechanisms of interaction for TLR4 and TLR4-related polysaccharides.

Astragalus polysaccharides affect insulin resistance by regulating the hepatic SIRT1-PGC-1α/PPARα-FGF21 signaling pathway in male Sprague Dawley rats undergoing catch-up growth

The present study investigated the effects of Astragalus polysaccharides (APS) on insulin resistance by modulation of hepatic sirtuin 1 (SIRT1)-peroxisome proliferator-activated receptor (PPAR)-γ coactivator (PGC)-1α/PPARα-fibroblast growth factor (FGF)21, and glucose and lipid metabolism. Thirty male Sprague Dawley rats were divided into three groups: A normal control group, a catch-up growth group and an APS-treated (APS-G) group. The latter two groups underwent food restriction for 4 weeks, prior to being provided with a high fat diet, which was available ad libitum. The APS-G group was orally treated with APS for 8 weeks, whereas the other groups were administered saline. Body weight was measured and an oral glucose tolerance test (OGTT) was conducted after 8 weeks. The plasma glucose and insulin levels obtained from the OGTT were assayed, and hepatic morphology was observed by light and transmission electron microscopy. In addition, the mRNA expression levels of PGC-1α/PPARα, and the protein expression levels of SIRT1, FGF21 and nuclear factor-κB were quantified in the liver and serum. APS treatment suppressed abnormal glycolipid metabolism and insulin resistance following 8 weeks of catch-up growth by improving hepatic SIRT1-PPARα-FGF21 intracellular signaling and reducing chronic inflammation, and by partially attenuating hepatic steatosis. The suppressive effects of APS on liver acetylation and glycolipid metabolism-associated molecules contributed to the observed suppression of insulin resistance. However, the mechanism underlying the effects of APS on insulin resistance requires further research in order to be elucidated. Rapid and long-term treatment with APS may provide a novel, safe and effective therapeutic strategy for type 2 diabetes.

Astragalus polysaccharides repress myocardial lipotoxicity in a PPARalpha-dependent manner in vitro and in vivo in mice

BACKGROUND

The role of peroxisome proliferator-activated receptor alpha (PPARα) in the development of myocardial lipotoxicity is widely observed in diabetic disorders. Thus, we investigated if treatment of Astragalus polysaccharides modulates lipotoxic cardiomyopathy both in vivo and in vitro through PPARα mechanisms.

METHODOLOGY/PRINCIPAL FINDINGS

The effects of Astragalus polysaccharides (APS) on PPARα target gene expression and protein levels were tested in vitro and in vivo, including in mice with PPARα cardiac-restricted overexpression [myosin heavy chain (MHC)-PPARα] and in H9c2 embryonic rat cardiomyocytes with or without PPARα agonist. Echocardiographic studies, analyses of myocardial triglyceride and cardiac fuel utilization analyses were also performed in MHC-PPARα mice. Treatment with APS prevented myocardial triglyceride accumulation and cardiac dysfunction in the MHC-PPARα mice, with the normalization of energy metabolic derangements in hearts including reduced free fatty acids utilization and increased glucose uptake. Consistently, both in the MHC-PPARα hearts and H9c2 cardiomyocytes with PPARα agonist, the activation of PPARα gene regulatory pathway involved in FFA-oxidation was down-regulated by APS treatment, while the suppression of PPARα target genes involved in glucose uptake and oxidation was normalized by APS administration.

CONCLUSIONS

Therapy with APS could prevent the development of lipotoxic cardiomyopathy through a mechanism mainly dependent on the cardiac PPARα-mediated regulatory pathways.

Emodin protects against diabetic cardiomyopathy by regulating the AKT/GSK-3β signaling pathway in the rat model

Diabetes mellitus (DM) has been recognized as a major health problem. Emodin (Emo) has been reported to exhibit protective effects against diabetic nephropathy. However, little has been known about the effect of Emo on diabetic cardiomyopathy (DCM). A type 2 DM model was induced in rats by low dose streptozotocin (STZ) combined with high energy intake. We found that Emo-treated groups displayed significantly higher body weight (BW) and lower heart weight (HW)/BW. Furthermore, Emo could significantly decrease blood glucose, total cholesterol (TG) levels, and triglyceride (TC) levels in diabetic rats. Moreover, the Emo-treated group showed a marked increase in heart rate (HR) and showed lower left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular posterior wall thickness (LWPWT), and interventricular septal diastolic wall thickness (IVSD). Emo induced a significant increase in phosphorylation of Akt and GSK-3β in myocardium. These results suggest that Emo may have great therapeutic potential in the treatment of DCM by Akt/GSK-3β signaling pathway.

Metabolic dysfunction in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is defined as cardiac disease independent of vascular complications during diabetes. The number of new cases of DCM is rising at epidemic rates in proportion to newly diagnosed cases of diabetes mellitus (DM) throughout the world. DCM is a heart failure syndrome found in diabetic patients that is characterized by left ventricular hypertrophy and reduced diastolic function, with or without concurrent systolic dysfunction, occurring in the absence of hypertension and coronary artery disease. DCM and other diabetic complications are caused in part by elevations in blood glucose and lipids, characteristic of DM. Although there are pathological consequences to hyperglycemia and hyperlipidemia, the combination of the two metabolic abnormalities potentiates the severity of diabetic complications. A natural competition exists between glucose and fatty acid metabolism in the heart that is regulated by allosteric and feedback control and transcriptional modulation of key limiting enzymes. Inhibition of these glycolytic enzymes not only controls flux of substrate through the glycolytic pathway, but also leads to the diversion of glycolytic intermediate substrate through pathological pathways, which mediate the onset of diabetic complications. The present review describes the limiting steps involved in the development of these pathological pathways and the factors involved in the regulation of these limiting steps. Additionally, therapeutic options with demonstrated or postulated effects on DCM are described.

Astragalus polysaccharide inhibits isoprenaline-induced cardiac hypertrophy via suppressing Ca²⁺-mediated calcineurin/NFATc3 and CaMKII signaling cascades

Pathological cardiac hypertrophy induced by increased sympathetic drive can subsequently lead to congestive heart failure, which represents the major cause of morbidity and mortality worldwide. Astragalus polysaccharide (APS) is an active compound extracted from Chinese herb Astragalus membranaceus (AM), a frequently used "Qi-invigorating" herbal medicine in traditional medicine broadly used for the treatment of cardiovascular and other diseases. Currently, little is known about the effect of APS on cardiac hypertrophy. In the present study, we aimed to investigate its effect on cardiac hypertrophy and to clarify its possible mechanisms. In vitro cardiac hypertrophic model induced by isoprenaline (ISO) was employed to explore the anti-hypertrophic action of APS. We found that 10 μM ISO treatment for 48 h caused cultured cardiomyocytes to undergo significant increases in cell surface area, total protein content, protein synthesis as well as the expression of hypertrophic markers, including atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), which were effectively inhibited by APS in a dose dependent manner. Moreover, we found that APS pretreatment alleviated the augment of intracellular free calcium during cardiac hypertrophy induced by ISO. Our further study revealed that the upregulated expression of calcineurin, translocation of nuclear factor of activated T cells, cytoplasmic 3 (NFATc3) into nucleus and activation of calmodulin kinase II (reflected by p-CaMKII) were dose dependently suppressed by the application of APS. According to this research, APS exerted its anti-hypertrophic action via inhibiting Ca(2+)-mediated calcineurin/NFATc3 and CaMKII signaling cascades, which provided new insights into the application of APS to the therapy of heart diseases.

High-throughput analysis and characterization of Astragalus membranaceus transcriptome using 454 GS FLX

Astragalus membranaceus (Fisch.) Bge (AR), one of the most important medicinal plants in Asia, was found to exhibit various bioactivities. Due to limited genomic and transcriptomic data, the biosynthetic pathway of the major bioactive compound in AR, is currently unclear. In this study, 454 GS FLX technology was employed to produce a substantial expressed sequence tag (EST) dataset from the AR. In all, 742721 high-quality reads from the AR were produced using Roche GS FLX Titanium. A total of 9893 unique sequences were obtained and annotated by a similarity search against the public databases, and involved in the secondary metabolic pathway, which would facilitate deciphering the molecular mechanism of secondary metabolism in AR. The assembled sequences were annotated with gene names and Gene Ontology (GO) terms. GO revealed the unique sequences that could be assigned to 34 vocabularies. In the KEGG mapping, unique sequences were established as associated with 46 biochemical pathways. These results provided the largest EST collections in AR and will contribute to biosynthetic and biochemical studies that lead to drug improvement. With respect to the genes related to metabolism and biosynthesis pathway were also found. Our work demonstrated the utility of 454 GS FLX as a method for the rapid and cost-effective identification of AR transcriptome, and this EST dataset will be a powerful resource for further studies such as taxonomy, molecular breeding, and secondary metabolism in AR.

Structural features and biological activities of the polysaccharides from Astragalus membranaceus

Recently, a great deal of interest has been developed to isolate and investigate novel bioactive components with health benefit effects from natural resources. The dried root of Astragalus membranaceus, one of the most popular health-promoting herbal medicines, has been used historically as an immunomodulating agent for the treatment of common cold, diarrhea, fatigue and anorexia for more than 2000 years. Modern phytochemistry and pharmacological experiments have proved that polysaccharide is one of the major active ingredients in the root of A. membranaceus with various important bioactivities, such as immunomodulation, antioxidant, antitumor, anti-diabetes, antiviral, hepatoprotection, anti-inflammation, anti-atherosclerosis, hematopoiesis and neuroprotection. The aim of the present review is to summarize previous and current references and give a comprehensive summary regarding the structural features and biological activities of A. membranaceus polysaccharides in order to provide new insight for further development of these macromolecules.

Recent Advances in Astragalus membranaceus Anti-Diabetic Research: Pharmacological Effects of Its Phytochemical Constituents

The disease burden of diabetes mellitus is increasing throughout the world. The need for more potent drugs to complement the present anti-diabetic drugs has become an imperative. Astragalus membranaceus, a key component of most Chinese herbal anti-diabetic formulas, has been an important prospect for lead anti-diabetic compounds. It has been progressively studied for its anti-diabetic properties. Ethnopharmacological studies have established its potential to alleviate diabetes mellitus. Recent studies have sought to relate its chemical constituents to types 1 and 2 diabetes mellitus. Its total polysaccharides, saponins, and flavonoids fractions and several isolated compounds have been the most studied. The total polysaccharides fraction demonstrated activity to both types 1 and 2 diabetes mellitus. This paper discusses the anti-diabetic effects and pharmacological action of the chemical constituents in relation to types 1 and 2 diabetes mellitus.

Chinese Medicinal Formula (MHGWT) for Relieving Diabetic Neuropathic Pain: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective. To investigate the effects of modified Hungqi Guizhi Wuwu Tang (MHGWT), a formula that comprises Chinese medicinal herbs, in relieving neuropathic pain in diabetics. Method. Between March 2008 and April 2009, 112 participants were randomly assigned to either the MHGWT group, whose members received MHGWT (n = 56), or the control group, whose members received a placebo (n = 56). Diabetic neuropathic pain (DNP) was rated using the 15-item Short-Form Brief Pain Inventory (SF-BPI), the 17-item Short-Form McGill Pain Questionnaire (SF-MPQ), the 13-item Modified Michigan Neuropathy Screening Instrument (MMNSI), and the 36-item “SF-36.” Nerve conduction studies (NCSs) were performed before and after treatment. Results. After 12 weeks of treatment, the SF-MPQ and SF-BPI scores of the MHGWT group were significantly (P < 0.05) reduced and a significant difference between the groups was observed (P < 0.05). The levels of NCS in the MHGWT group were nonsignificantly (P > 0.05) reduced, and no significant difference in NCS level was observed between the groups (P > 0.05). Conclusions. MHGWT shows promise in relieving DNP and deserves further investigation.