Atorvastatin prevents advanced glycation end products (AGEs)-induced cardiac fibrosis via activating peroxisome proliferator-activated receptor gamma (PPAR-γ)

Decoding the role of aldosterone in glycation-induced diabetic complications

Diabetes-mediated development of micro and macro-vascular complications is a global concern. One of the factors is hyperglycemia induced the non-enzymatic formation of advanced glycation end products (AGEs). Accumulated AGEs bind with receptor of AGEs (RAGE) causing inflammation, oxidative stress and extracellular matrix proteins (ECM) modifications responsible for fibrosis, cell damage and tissue remodeling. Moreover, during hyperglycemia, aldosterone (Aldo) secretion increases, and its interaction with mineralocorticoid receptor (MR) through genomic and non-genomic pathways leads to inflammation and fibrosis. Extensive research on individual involvement of AGEs-RAGE and Aldo-MR pathways in the development of diabetic nephropathy (DN), cardiovascular diseases (CVDs), and impaired immune system has led to the discovery of therapeutic drugs. Despite mutual repercussions, the cross-talk between AGEs-RAGE and Aldo-MR pathways remains unresolved. Hence, this review focuses on the possible interaction of Aldo and glycation in DN and CVDs, considering the clinical significance of mutual molecular targets.

Investigation of the Dysfunction Caused by High Glucose, Advanced Glycation End Products, and Interleukin-1 Beta and the Effects of Therapeutic Agents on the Microphysiological Artery Model

Diabetes mellitus (DM) has substantial global implications and contributes to vascular inflammation and the onset of atherosclerotic cardiovascular diseases. However, translating the findings from animal models to humans has inherent limitations, necessitating a novel platform. Therefore, herein, an arterial model is established using a microphysiological system. This model successfully replicates the stratified characteristics of human arteries by integrating collagen, endothelial cells (ECs), and vascular smooth muscle cells (VSMCs). Perfusion via a peristaltic pump shows dynamic characteristics distinct from those of static culture models. High glucose, advanced glycation end products (AGEs), and interleukin-1 beta are employed to stimulate diabetic conditions, resulting in notable cellular changes and different levels of cytokines and nitric oxide. Additionally, the interactions between the disease models and oxidized low-density lipoproteins (LDL) are examined. Finally, the potential therapeutic effects of metformin, atorvastatin, and diphenyleneiodonium are investigated. Metformin and diphenyleneiodonium mitigate high-glucose- and AGE-associated pathological changes, whereas atorvastatin affects only the morphology of ECs. Altogether, the arterial model represents a pivotal advancement, offering a robust and insightful platform for investigating cardiovascular diseases and their corresponding drug development.

Targeting MAPK-ERK/JNK pathway: A potential intervention mechanism of myocardial fibrosis in heart failure

Myocardial fibrosis is a significant pathological basis of heart failure. Overactivation of the ERK1/2 and JNK1/2 signaling pathways of MAPK family members synergistically promotes the proliferation of myocardial fibroblasts and accelerates the development of myocardial fibrosis. In addition to some small molecule inhibitors and Western drugs, many Chinese medicines can also inhibit the activity of ERK1/2 and JNK1/2, thus slowing down the development of myocardial fibrosis, and are generally safe and effective. However, the specific biological mechanisms of ERK1/2 and JNK1/2 signaling pathways in myocardial fibrosis still need to be fully understood, and there is no systematic review of existing drugs and methods to inhibit them from improving myocardial fibrosis. This study aims to summarize the roles and cross-linking mechanisms of ERK1/2 and JNK1/2 signaling pathways in myocardial fibrosis and to systematically sort out the small-molecule inhibitors, Western drugs, traditional Chinese medicines, and non-pharmacological therapies that inhibit ERK1/2 and JNK1/2 to alleviate myocardial fibrosis. In the future, we hope to conduct more in-depth research from the perspective of precision-targeted therapy, using this as a basis for developing new drugs that provide new perspectives on the prevention and treatment of heart failure.

JAK/STAT3 signaling in cardiac fibrosis: a promising therapeutic target

Cardiac fibrosis is a serious health problem because it is a common pathological change in almost all forms of cardiovascular diseases. Cardiac fibrosis is characterized by the transdifferentiation of cardiac fibroblasts (CFs) into cardiac myofibroblasts and the excessive deposition of extracellular matrix (ECM) components produced by activated myofibroblasts, which leads to fibrotic scar formation and subsequent cardiac dysfunction. However, there are currently few effective therapeutic strategies protecting against fibrogenesis. This lack is largely because the molecular mechanisms of cardiac fibrosis remain unclear despite extensive research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling cascade is an extensively present intracellular signal transduction pathway and can regulate a wide range of biological processes, including cell proliferation, migration, differentiation, apoptosis, and immune response. Various upstream mediators such as cytokines, growth factors and hormones can initiate signal transmission via this pathway and play corresponding regulatory roles. STAT3 is a crucial player of the JAK/STAT pathway and its activation is related to inflammation, malignant tumors and autoimmune illnesses. Recently, the JAK/STAT3 signaling has been in the spotlight for its role in the occurrence and development of cardiac fibrosis and its activation can promote the proliferation and activation of CFs and the production of ECM proteins, thus leading to cardiac fibrosis. In this manuscript, we discuss the structure, transactivation and regulation of the JAK/STAT3 signaling pathway and review recent progress on the role of this pathway in cardiac fibrosis. Moreover, we summarize the current challenges and opportunities of targeting the JAK/STAT3 signaling for the treatment of fibrosis. In summary, the information presented in this article is critical for comprehending the role of the JAK/STAT3 pathway in cardiac fibrosis, and will also contribute to future research aimed at the development of effective anti-fibrotic therapeutic strategies targeting the JAK/STAT3 signaling.

Advanced glycation end products: Key mediator and therapeutic target of cardiovascular complications in diabetes

The incidence of type 2 diabetes mellitus is growing in epidemic proportions and has become one of the most critical public health concerns. Cardiovascular complications associated with diabetes are the leading cause of morbidity and mortality. The cardiovascular diseases that accompany diabetes include angina, myocardial infarction, stroke, peripheral artery disease, and congestive heart failure. Among the various risk factors generated secondary to hyperglycemic situations, advanced glycation end products (AGEs) are one of the important targets for future diagnosis and prevention of diabetes. In the last decade, AGEs have drawn a lot of attention due to their involvement in diabetic patho-physiology. AGEs can be derived exogenously and endogenously through various pathways. These are a non-homogeneous, chemically diverse group of compounds formed non-enzymatically by condensation between carbonyl groups of reducing sugars and free amino groups of protein, lipids, and nucleic acid. AGEs mediate their pathological effects at the cellular and extracellular levels by multiple pathways. At the cellular level, they activate signaling cascades via the receptor for AGEs and initiate a complex series of intracellular signaling resulting in reactive oxygen species generation, inflammation, cellular proliferation, and fibrosis that may possibly exacerbate the damaging effects on cardiac functions in diabetics. AGEs also cause covalent modifications and cross-linking of serum and extracellular matrix proteins; altering their structure, stability, and functions. Early diagnosis of diabetes may prevent its progression to complications and decrease its associated comorbidities. In the present review, we recapitulate the role of AGEs as a crucial mediator of hyperglycemia-mediated detrimental effects in diabetes-associated complications. Furthermore, this review presents an overview of future perspectives for new therapeutic interventions to ameliorate cardiovascular complications in diabetes.

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

AGER1 deficiency-triggered ferroptosis drives fibrosis progression in nonalcoholic steatohepatitis with type 2 diabetes mellitus

Hyperglycemia is an independent risk factor for the rapid progression of nonalcoholic steatohepatitis (NASH) to liver fibrosis with an incompletely defined mechanism. Ferroptosis is a novel form of programmed cell death that has been identified as a pathogenic mechanism in various diseases. However, the role of ferroptosis in the development of liver fibrosis in NASH with type 2 diabetes mellitus (T2DM) is unclear. Here, we observed the histopathological features of the progression of NASH to liver fibrosis as well as hepatocyte epithelial-mesenchymal transition (EMT) in a mouse model of NASH with T2DM and high-glucose-cultured steatotic human normal liver (LO2) cells. The distinctive features of ferroptosis, including iron overload, decreased antioxidant capacity, the accumulation of reactive oxygen species, and elevated lipid peroxidation products, were confirmed in vivo and in vitro. Liver fibrosis and hepatocyte EMT were markedly alleviated after treatment with the ferroptosis inhibitor ferrostatin-1. Furthermore, a decrease in the gene and protein levels of AGE receptor 1 (AGER1) was detected in the transition from NASH to liver fibrosis. Overexpression of AGER1 dramatically reversed hepatocyte EMT in high-glucose-cultured steatotic LO2 cells, whereas the knockdown of AGER1 had the opposite effect. The mechanisms underlying the phenotype appear to be associated with the inhibitory effects of AGER1 on ferroptosis, which is dependent on the regulation of sirtuin 4. Finally, in vivo adeno-associated virus-mediated AGER1 overexpression effectively relieved liver fibrosis in a murine model. Collectively, these findings suggest that ferroptosis participates in the pathogenesis of liver fibrosis in NASH with T2DM by promoting hepatocyte EMT. AGER1 could reverse hepatocyte EMT to ameliorate liver fibrosis by inhibiting ferroptosis. The results also suggest that AGER1 may be a potential therapeutic target for the treatment of liver fibrosis in patients with NASH with T2DM. Chronic hyperglycemia is associated with increased advanced glycation end products, resulting in the downregulation of AGER1. AGER1 deficiency downregulates Sirt4, which disturbs key regulators of ferroptosis (TFR-1, FTH, GPX4, and SLC7A11). These lead to increased iron uptake, decreasing the antioxidative capacity and enhanced lipid ROS production, ultimately leading to ferroptosis, which further promotes hepatocyte epithelial-mesenchymal transition and fibrosis progression in NASH with T2DM.

RAGE pathways play an important role in regulation of organ fibrosis

Organ fibrosis is a pathological process of fibroblast activation and excessive deposition of extracellular matrix after persistent tissue injury and therefore is a common endpoint of many organ pathologies. Multiple cellular types and soluble mediators, including chemokines, cytokines and non-peptidic factors, are implicated in fibrogenesis and the remodeling of tissue architecture. The molecular basis of the fibrotic process is complex and consists of closely intertwined signaling networks. Research has strived for a better understanding of these pathological mechanisms to potentially reveal novel therapeutic targets for fibrotic diseases. In light of new knowledge, the receptor for advanced glycation end products (RAGE) emerged as an important candidate for the regulation of a wide variety of cellular functions related to fibrosis, including inflammation, cell proliferation, apoptosis, and angiogenesis. RAGE is a pattern recognition receptor that binds a broad range of ligands such as advanced glycation end products, high mobility group box-1, S-100 calcium-binding protein and amyloid beta protein. Although the link between RAGE and fibrosis has been established, the exact mechanisms need be investigated in further studies. The aim of this review is to collect all available information about the intricate function of RAGE and its signaling cascades in the pathogenesis of fibrotic diseases within different organs. In addition, to the major ligands and signaling pathways, we discuss potential strategies for targeting RAGE in fibrosis. We emphasize the functional links between RAGE, inflammation and fibrosis that may guide further studies and the development of improved therapeutic drugs.

Effects of RAGE Deletion on the Cardiac Transcriptome during Aging

Cardiac aging is characterized by increased cardiomyocyte hypertrophy, myocardial stiffness, and fibrosis, which enhance cardiovascular risk. The receptor for advanced glycation end-products (RAGE) is involved in several age-related diseases. RAGE knockout (Rage−/−) mice show an acceleration of cardiac dimension changes and interstitial fibrosis with aging. This study identifies the age-associated cardiac gene expression signature induced by RAGE deletion. We analyzed the left ventricle transcriptome of 2.5-(Young), 12-(Middle age, MA), and 21-(Old) months-old female Rage−/− and C57BL/6N (WT) mice. By comparing Young, MA, and Old Rage−/− versus age-matched WT mice, we identified 122, 192, and 12 differently expressed genes, respectively. Functional inference analysis showed that RAGE deletion is associated with: (i) down-regulation of genes involved in antigen processing and presentation of exogenous antigen, adaptive immune response, and cellular responses to interferon beta and gamma in Young animals; (ii) up-regulation of genes related to fatty acid oxidation, cardiac structure remodeling and cellular response to hypoxia in MA mice; (iii) up-regulation of few genes belonging to complement activation and triglyceride biosynthetic process in Old animals. Our findings show that the age-dependent cardiac phenotype of Rage−/− mice is associated with alterations of genes related to adaptive immunity and cardiac stress pathways.

The Use of Ellagic Acid and Annona Muricata Improves Semen Quality in Men with High-Risk Papillomavirus Infection

Background: Few data are currently available on the treatment of patients with HPV infection. In particular, there is no agreement on the use of antioxidants in these patients. Ellagic acid and annona muricata appear to improve HPV clearance in infected women. However, it is presently unknown whether they could enhance the clearance of HPV infection in infertile male patients. Aim: To evaluate the effects of a commercially available combined compound containing ellagic acid and annona muricata on semen quality in patients with documented papillomavirus (HPV) infection, and on the frequency of HPV DNA detection in seminal fluid after treatment. In addition, anti-sperm antibodies and the percentage of spermatozoa with fragmented DNA were evaluated. Materials and methods: This was a retrospective case-control study including patients attending our center for infertility. Fifty selected patients who were positive for high risk (HR)-HPV with available semen analysis results were consecutively enrolled. Patients were classified into two groups, according to the clinician’s decision to either administer ellagic acid 100 mg and annona muricata 100 mg (combined tablet formulation) for a period of three months (Group A; 25 patients), or to re-evaluate HPV DNA after a period of active surveillance only (protected sexual intercourse) (Group B; 25 patients). Results: Group A patients had a mean age of 31.0  ±  11.0 years, while Group B was 33.0  ±  8.0 years old (p  > 0.05). After three months of treatment with ellagic acid and annona muricata, all conventional seminal parameters improved more significantly in Group A than in Group B patients: sperm concentration = 45 mil/mL vs. 20 mil/mL (p < 0.05); sperm progressive motility = 45% vs. 18% (p < 0.05); and normal sperm morphology = 18% vs. 6% (p < 0.05). After the treatment, the frequency of persistence of HPV DNA in the seminal fluid was significantly lower in Group A patients compared to those in Group B (12/25 = 48% vs. 22/25 = 88%; p < 0.05). Finally, after 3 months, Group A showed a significant reduction in anti-sperm antibodies and in the percentage of spermatozoa with fragmented DNA. Conclusion: The results of this study demonstrate, for the first time, the effects of a commercially available combined compound containing ellagic acid and annona muricata on semen quality in patients with HR-HPV infection, and that this therapy is also associated with a significant reduction in the persistence of HPV DNA in the seminal fluid.

Pleiotropic Benefits of Statins in Cardiovascular Diseases

In 1976, Japanese microbiologist Akira Endo discovered the first statin as a product of the fungus Penicillium citrinum that inhibited the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Their primary mode of action is to lower the blood cholesterol by decreasing hepatic cholesterol production, which upregulates hepatic low-density lipoprotein (LDL) receptors and increases LDL-cholesterol clearance. In addition to cholesterol lowering, statins inhibit other downstream products of the mevalonate pathway, causing the so-called pleiotropic effects. As a result of their pleiotropic effects statins modulate virtually all known processes of atherosclerosis and have beneficial effects outside the cardiovascular system Statins inhibit the post-translational prenylation of small GTP-binding proteins such as Rho, Rac, as well as their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases since they suppress the synthesis of isoprenoid intermediates in the cholesterol biosynthetic pathway altering the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, production of proinflammatory cytokines, reactive oxygen species, platelet reactivity, development of cardiac hypertrophy and fibrosis in cell culture and animal experiments. Inhibition of Rho and Rho-associated coiled-coil containing protein kinase (ROCK), has emerged as the principle mechanisms underlying the pleiotropic effects of statins. However, the relative contributions of statin pleiotropy to clinical outcomes are debatable and difficult to measure because the amount of isoprenoid inhibition by statins corresponds to some extent with the amount of LDL-cholesterol decrease. This article examines some of the existing molecular explanations underlying statin pleiotropy and discusses if they have clinical relevance in cardiovascular diseases.

An overview of possible pivotal mechanisms of Genistein as a potential phytochemical against SARS-CoV-2 infection: A hypothesis

The Coronavirus Disease 2019 (COVID‐19) pandemic has been caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). It is a global problem that humanity has not yet found a definitive solution for it. In this regard, a global effort has been done to find effective or potential adjuvant therapies in order to fight this infection. Genistein is a small, biologically active phytoestrogen flavonoid that is found in high amounts in soy and plants of the Fabaceae family. This important compound is known due to its anti‐cancer, anti‐inflammatory, and antioxidant effects. Additionally, protective effects of genistein have been reported in different pathological conditions through modulating intracellular pathways such as PI3K, Akt, mTOR, NF‐κB, PPARγ, AMPK, and Nrf2. Scientific evidence suggests that genistein could have a potential role to treat COVID‐19 through its anti‐inflammatory and anti‐oxidant effects. Furthermore, it appears to interfere with intracellular pathways involved in viral entry into the cell. This review provides a basis for further research and development of clinical applications of genistein as a potential alternative therapy to decrease inflammation and oxidative stress in COVID‐19 patients.

Inhibition of Gli1 suppressed hyperglycemia-induced meibomian gland dysfunction by promoting pparγ expression

Diabetes is one of the risk factors for meibomian gland dysfunction (MGD); however, the underlying molecular mechanism remains unknown. The current study aims to examine the effects of glioma-associated oncogene homolog 1 (Gli1), a transcription factor of the sonic hedgehog (Shh) pathway, in the modulation of diabetic-related MGD. Here, using RNA sequencing and qRT-PCR, we examined the mRNA changes of Shh pathway involving genes. mRNA sequencing analysis showed that the Shh pathway involving genes Shh and Gli1 were markedly upregulated in diabetic MG, and qRT-PCR detection of Shh pathway-associated genes found that Gli1 expression increased most significantly. Contrary to the elevation of Gli1 level, the expression of pparγ was downregulated in diabetic MG and in high glucose treated organotypic cultured mouse MG. GANT61, an inhibitor of Gli1, effectively inhibited the reduction of pparγ expression and lipid accumulation induced by high glucose, which was suppressed by pparγ inhibitor T0070907. We further demonstrated that advanced glycation end products (AGEs) treatment also promoted the expression of Gli1 and pparγ in organotypic cultured mouse MG. AGEs inhibitor Aminoguanidine suppressed high glucose caused Gli1 upregulation in organotypic cultured mouse MG. These results suggest that suppression of Gli1 may be a potentially useful therapeutic option for diabetic-related MGD.

Advanced Glycation End Product Blocker Drugs Have a Great Potential to Prevent Diabetic Cardiomyopathy in an Animal Model of Diabetes Mellitus Type-2

Introduction

Sphingosine 1 phosphate (S1P) is a product of the sphingosine kinase 1 (SphK1) enzyme. Increased S1P can lead to tissue fibrosis that is also one of the pathways for developing diabetic cardiomyopathy. Advanced glycation end products (AGEs) increase S1P in cells. The study is aimed at using aminoguanidine (AG) as an AGEs blocker drug to prevent diabetic cardiomyopathy. Materials and methods. 210 rats were enrolled in the study. Diabetes mellitus type-2 was induced, and rats were divided into AG treated diabetic and nondiabetic groups. The heart histology was assessed with Masson's trichrome and hematoxylin-eosin staining. Cardiac function was measured with transthoracic echocardiography. S1P level and SphK1 gene expression were measured by western-blot and RT-qPCR, respectively.

Results

Results showed that S1P level increases in diabetes, and its augmentation in cardiac tissue with K6PC-5 leads to cardiac fibrosis. 50 and 200 mg/kg of AG prevented cardiac fibrosis, but 100 mg/kg had no significant preventive effect. AG suppressed the SphK1 gene expression and reduced the fibrotic effect of S1P. AG preserved cardiac function by keeping ejection fraction and fractional shortening within the normal range in diabetic rats.

Conclusion

AG has a suppressor effect on SphK1 gene expression besides its AGEs blocker role. AG is a potential drug to use in diabetic patients for preventing the development of diabetic cardiomyopathy. Other drugs that have AGEs or S1P blocker effects are a good choice for diabetic cardiomyopathy prevention.

Angiotensin II receptor blocker and statin combination therapy associated with higher skeletal muscle index in patients with cardiovascular disease: A retrospective study

WHAT IS KNOWN AND OBJECTIVE

Reduction in skeletal muscle mass is the most important component in diagnosing sarcopenia. Ageing and chronic heart failure due to cardiovascular diseases (CVDs) accelerate the reduction of skeletal muscles. However, there are no currently available drugs that are effective for sarcopenia. The purpose of this study was to explore the association between prescribed medications and skeletal muscle mass in patients with CVD.

METHODS

This was a single-centre, retrospective, cross-sectional study. The subjects were 636 inpatients with CVD who took prescribed medicines for at least 4 weeks at the time of admission. Skeletal muscle volume was assessed using a bioelectrical impedance assay.

RESULTS AND DISCUSSION

Single regression analysis showed that 10 and 3 medications were positively and negatively associated with skeletal muscle index (SMI), respectively. Stepwise multivariate regression analysis revealed that angiotensin II receptor blocker (ARB)/statin combination, dipeptidyl peptidase-4 inhibitor, and antihyperuricemic agents were positively associated with SMI while diuretics and antiarrhythmic agents were negatively associated with SMI. After adjustment using propensity score matching, the SMI was found to be significantly higher in ARB/statin combination users than in non-users.

WHAT IS NEW AND CONCLUSION

Combination use of ARB/statin was associated with a higher SMI in patients with CVD. A future randomised, controlled trial is warranted to determine whether the ARB/statin combination will increase the SMI and prevent sarcopenia in patients with CVD.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

Advanced Glycation End Products: New Clinical and Molecular Perspectives

Diabetes mellitus (DM) is considered one of the most massive epidemics of the twenty-first century due to its high mortality rates caused mainly due to its complications; therefore, the early identification of such complications becomes a race against time to establish a prompt diagnosis. The research of complications of DM over the years has allowed the development of numerous alternatives for diagnosis. Among these emerge the quantification of advanced glycation end products (AGEs) given their increased levels due to chronic hyperglycemia, while also being related to the induction of different stress-associated cellular responses and proinflammatory mechanisms involved in the progression of chronic complications of DM. Additionally, the investigation for more valuable and safe techniques has led to developing a newer, noninvasive, and effective tool, termed skin fluorescence (SAF). Hence, this study aimed to establish an update about the molecular mechanisms induced by AGEs during the evolution of chronic complications of DM and describe the newer measurement techniques available, highlighting SAF as a possible tool to measure the risk of developing DM chronic complications.

Soluble Receptor for Advanced Glycation End-products regulates age-associated Cardiac Fibrosis

Myocardial aging increases the cardiovascular risk in the elderly. The Receptor for Advanced Glycation End-products (RAGE) is involved in age-related disorders. The soluble isoform (sRAGE) acts as a scavenger blocking the membrane-bound receptor activation. This study aims at investigating RAGE contribution to age-related cardiac remodeling.

We analyzed the cardiac function of three different age groups of female Rage-/- and C57BL/6N (WT) mice: 2.5- (Young), 12- (Middle-age, MA) and 21-months (Old) old. While aging, Rage-/- mice displayed an increase in left ventricle (LV) dimensions compared to age-matched WT animals, with the main differences observed in the MA groups. Rage-/- mice showed higher fibrosis and a larger number of α-Smooth Muscle Actin (SMA)+ cells with age, along with increased expression of pro-fibrotic Transforming Growth Factor (TGF)-β1 pathway components. RAGE isoforms were undetectable in LV of WT mice, nevertheless, circulating sRAGE declined with aging and inversely associated with LV diastolic dimensions. Human cardiac fibroblasts stimulated with sRAGE exhibited a reduction in proliferation, pro-fibrotic proteins and TGF-beta Receptor 1 (TGFbR1) expression and Smad2-3 activation. Finally, sRAGE administration to MA WT animals reduced cardiac fibrosis.

Hence, our work shows that RAGE associates with age-dependent myocardial changes and indicates sRAGE as an inhibitor of cardiac fibroblasts differentiation and age-dependent cardiac fibrosis.

Potential Antioxidative, Anti-inflammatory and Immunomodulatory Effects of Ghrelin, an Endogenous Peptide from the Stomach in SARS-CoV2 Infection

The current COVID-19 pandemic is one of the most devastating events in recent history. The respiratory effects of this disease include acute respiratory distress syndrome, systemic inflammation, cytokine storm, and pulmonary fibrosis. Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is a peptide hormone secreted mainly by the stomach. Interestingly, ghrelin possesses promising antioxidant, anti-and inflammatory effects, making it an attractive agent to reduce the complications of the SARS-CoV-2. In addition, ghrelin exerts a wide range of immunomodulatory and anti-inflammatory effects and can mitigate the uncontrolled cytokine production responsible for acute lung injury by upregulating PPARγ and down-regulating NF-κB expression. Ghrelin has also been reported to enhance Nrf2 expression in inflammatory conditions which led to the suppression of oxidative stress. The current opinion summarizes the evidence for the possible pharmacological benefits of ghrelin in the therapeutic management of SARS-CoV-2 infection.

Pathological changes of frozen shoulder in rat model and the therapeutic effect of PPAR-γ agonist

Frozen shoulder is a common shoulder disorder characterized by a gradual increase of pain and a limited range of motion. However, its pathophysiologic mechanisms remain unclear and there is no consensus as to the most effective treatment. The purpose of the study was to investigate the effect of transforming growth factor-β (TGF-β) on fibrosis and inflammatory response of the shoulder joint of rat models and to explore the therapeutic effect of the peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist. In the study, the effect of PPAR-γ agonist CDDO-IM treatment on cell proliferation, migration, and extracellular matrix proteins synthesis (vimentin, α-smooth muscle actin, collagen I, and collagen III) were tested by cell proliferation test, scratches test, real-time quantitative polymerase chain reaction, and Western blot analysis. The frozen shoulder was also established on the rat model by injecting adenovirus-TGF-β1 into rats' shoulder capsule. Pathological changes of the frozen shoulder tissue of the experimental group and PPAR-γ agonist treatment group were evaluated. The stiffness of joints of the three groups was tested. Inflammatory mediators' expression including cyclooxygenase-1, interleukin-1β, and tumor necrosis factor-α of the shoulder was tested by enzyme-linked immunosorbent assay, and the expression of extracellular matrix proteins was evaluated by hematoxylin and eosin staining and immunohistochemistry. The results showed that pathological changes of the frozen shoulder in the rat model include an abnormal proliferation of fibroblasts, infiltration of inflammatory cells, and disorder of fibrous structure, while rosiglitazone reduced the severity of the frozen shoulder in the treatment group. Clinically, PPAR-γ agonists may be a promising target for the treatment of the frozen shoulder.

Effects of statins on myocarditis: A review of underlying molecular mechanisms

Myocarditis refers to the clinical and histological characteristics of a diverse range of inflammatory cellular pathophysiological conditions which result in cardiac dysfunction. Myocarditis is a major cause of mortality in individuals less than 40 years of age and accounts for approximately 20% of cardiovascular disease (CVD) events. Myocarditis contributes to dilated cardiomyopathy in 30% of patients and can progress to cardiac arrest, which has a poor prognosis of <40% survival over 10 years. Myocarditis has also been documented after infection with SARS-CoV-2. The most commonly used lipid-lowering therapies, HMG-CoA reductase inhibitors (statins), decrease CVD-related morbidity and mortality. In addition to their lipid-lowering effects, increasing evidence supports the existence of several additional beneficial, 'pleiotropic' effects of statins. Recently, several studies have indicated that statins may attenuate myocarditis. Statins modify the lipid oxidation, inflammation, immunomodulation, and endothelial activity of the pathophysiology and have been recommended as adjuvant treatment. In this review, we focus on the mechanisms of action of statins and their effects on myocarditis, SARS-CoV-2 and CVD.

Emerging role of CCN family proteins in fibrosis

Fibrosis is a common pathological change characterized by the excessive accumulation of fibrous connective tissue. Once uncontrolled, this pathological progress can lead to irreversible damage to the structure and function of organs, which is a serious threat to human health and life. Actually, the disability and death of patients caused by many chronic diseases have a closed relationship with fibrosis. The CCN protein family, including six members, is a small group of matrix proteins exhibiting structurally similar features. In the past 20 years, different biological functions of CCN proteins have been identified in various diseases. Of note, it has been recently shown that they are implicated in the key pathological process of fibrosis. In this review, we summarize the current status of knowledge regarding the role of CCN proteins involved in the pathogenesis of fibrosis diseases in detail. Furthermore, we highlight some of the underlying interaction mechanisms of CCN protein acting in fibrosis that helps to develop new drugs and determine appropriate clinical strategies for fibrotic diseases.

Targeting peroxisome proliferator-activated receptors: A new strategy for the treatment of cardiac fibrosis

Cardiac fibrosis is a pathogenic factor of many cardiovascular diseases (CVD), which seriously affects people's life, and health and causes huge economic losses. Increasing evidence has shown that peroxisome proliferator-activated receptors (PPARs) can regulate the progression of cardiac fibrosis. For the first time, this review systematically summarizes the literature on cardiac fibrosis from the perspective of PPARs from 2010 to 2020. Moreover, the role of each PPARs in cardiac fibrosis was clarified in this scientific revision from the perspectives of pharmacologically active substances, known agonists, natural extract compounds, and nucleic-acid-based drugs in different CVD models. Furthermore, the combination of multiple PPARs on the treatment of cardiac fibrosis is discussed. This scientific review provides new ideas for targeting PPARs in the treatment of cardiac fibrosis and provides strategies for the development of new, safe, and effective pharmacological antagonists against cardiac fibrosis based on PPAR activity.

Peroxisome proliferator-activated receptor-γ mediates the antihypertensive effects of acupuncture in spontaneously hypertensive rats

We investigated a central antihypertensive effect of acupuncture in rostral ventrolateral medulla (RVLM) in spontaneously hypertensive rats (SHRs). In total, 56 rats were randomly divided into seven groups as follows: the SHR group, SHR+acupuncture (SHR+Acu) group, SHR+nonacupuncture (SHR+Non-acu) group, GW9662+acupuncture (GW9662+Acu) group, GW9662+GW1929 group, GW9662 group, and 2% DMSO group (n = 8 per group). The whole eight Wistar-Kyoto rats were assigned to the WKY group. The acupuncture treatment lasting for 14 days was performed at the Taichong acupoint (LR3) or at a nonacupoint (non-acu) once daily. The peroxisome proliferator-activated receptor (PPAR)-γ agonist GW1929 and the PPAR-γ inhibitor GW9662 were microinjected by the brain stereotactic technique. Blood pressure was measured by the tail-cuff method. Sympathetic vasomotor activity was determined by implanting in a telemetry electrocardiogram radio transmitter. The expression of PPARs in the RVLM of the rats was detected using Western blot. We demonstrated that acupuncture attenuated blood pressure, heart rate, and sympathetic vasomotor activity in SHRs. The protein expression of PPAR-γ was significantly increased in SHRs treated with acupuncture. The antihypertensive effects of acupuncture in SHRs were abrogated by microinjection bilaterally into RVLM of GW9662. Microinjection of GW1929 mimicked the antihypertensive effect of acupuncture. PPAR-γ expression was negatively correlated with blood pressure and sympathetic vasomotor activity in SHRs treated with acupuncture. These results suggested that acupuncture promoted a central antihypertensive effect by increasing the expression of PPAR-γ in RVLM of SHRs.

Randomized double-blind clinical trial examining the Ellagic acid effects on glycemic status, insulin resistance, antioxidant, and inflammatory factors in patients with type 2 diabetes

Oxidative stress can worsen glycemic status. Considering the antioxidant properties of Ellagic acid (EA), this study was designed to evaluate the effect of EA on glycemic indices, lipid profile, oxidative stress, and inflammation status in type 2 diabetic patients. Overall, 44 patients were recruited and were randomly allocated consumed 180 mg of EA per day (n = 22) or placebo (n = 22) for 8 weeks. The blood sugar (BS), insulin, insulin resistance (IR), hemoglobin A1c (HbA₁ c), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), total antioxidant capacity (TAC), malondialdehyde (MDA), the activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD), C-reactive protein (CRP), TNF-α and interleukin 6 (IL-6) were measured at the beginning and end of the study. At the end of the study, the mean of BS, insulin, IR, HbA₁ c, TC, TG, LDL, MDA, CRP, TNF-α, and IL-6 were significantly decreased in the intervention group (p < .05). Also, the mean of TAC (+0.8 ± 0.01) and activity of GPx (+10.26 ± 0.22) and SOD enzymes (+459.6 ± 9.76) significantly increased in the intervention group (p < .05). EA supplementation can be helpful as a diet supplement in patients with type 2 diabetes through improvement in chronic adverse effects.

Role of peroxisome proliferators-activated receptor-gamma in advanced glycation end product-mediated functional loss of voltage-gated potassium channel in rat coronary arteries

Background

High blood glucose impairs voltage-gated K⁺ (Kv) channel-mediated vasodilation in rat coronary artery smooth muscle cells (CSMCs) via oxidative stress. Advanced glycation end product (AGE) and receptor for AGE (RAGE) axis has been found to impair coronary dilation by reducing Kv channel activity in diabetic rat small coronary arteries (RSCAs). However, its underlying mechanism remain unclear. Here, we used isolated arteries and primary CSMCs to investigate the effect of AGE incubation on Kv channel-mediated coronary dilation and the possible involvement of peroxisome proliferators-activated receptor (PPAR) -γ pathway.

Methods

The RSCAs and primary CSMCs were isolated, cultured, and treated with bovine serum albumin (BSA), AGE-BSA, alagrebrium (ALA, AGE cross-linking breaker), pioglitazone (PIO, PPAR-γ activator) and/or GW9662 (PPAR-γ inhibitor). The groups were accordingly divided as control, BSA, AGE, AGE + ALA, AGE + PIO, or AGE + PIO + GW9662. Kv channel-mediated dilation was analyzed using wire myograph. Histology and immunohistochemistry of RSCAs were performed. Western blot was used to detect the protein expression of RAGE, major Kv channel subunits expressed in CSMCs (Kv1.2 and Kv1.5), PPAR-γ, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-2 (NOX-2).

Results

AGE markedly reduced Forskolin-induced Kv channel-mediated dilation of RSCAs by engaging with RAGE, and ALA or PIO significantly reversed the functional loss of Kv channel. In both RSCAs and CSMCs, AGE reduced Kv1.2/1.5 expression, increased RAGE and NOX-2 expression, and inhibited PPAR-γ expression, while ALA or PIO treatment partially reversed the inhibiting effects of AGE on Kv1.2/1.5 expression, accompanied by the downregulation of RAGE and decreased oxidative stress. Meanwhile, silencing of RAGE with siRNA remarkably alleviated the AGE-induced downregulation of Kv1.2/1.5 expression in CSMCs.

Conclusion

AGE reduces the Kv channel expression in CSMCs and further impairs the Kv channel-mediated dilation in RSCAs. The AGE/RAGE axis may enhance oxidative stress by inhibiting the downstream PPAR-γ pathway, thus playing a critical role in the dysfunction of Kv channels.

Long-term atorvastatin or the combination of atorvastatin and nicotinamide ameliorate insulin resistance and left ventricular diastolic dysfunction in a murine model of obesity

Current studies aimed at investigating the association between atorvastatin therapy and insulin resistance (IR) appear to be controversial. IR is considered to be an important contributor to inducing cardiac dysfunction through multiple signals. The paradoxical cardiotoxicity of atorvastatin reported under different conditions suggests that the association between atorvastatin treatment, insulin resistance and cardiac function should be clarified further. In this study, C57BL/6 J male mice were fed a high-fat diet (HD) or standard chow diet (SD) for 12 weeks and subsequently randomly divided into four groups: the SD-Control (SD-C) and HD-Control (HD-C) groups treated with saline for 10 months and the HD-A and HD-A + N groups treated with atorvastatin (20 mg/kg/day) alone or atorvastatin combined with nicotinamide (NAM, 1 g/kg/day) for 10 months. Although no significant changes in systolic function and structure were observed between the four groups of mice at an age of 46 or 58 weeks, respectively, long-term treatment with atorvastatin alone or atorvastatin and NAM combination significantly retarded the HD-induced IR and diastolic dysfunction and attenuated both cardiac and hepatic fibrosis in obese mice possibly by regulating the cleavage of osteopontin and then controlling profibrotic activity. Changes in cardiac function and structure were similar between the HD-A and HD-A + N groups; however, mice in the HD-A + N group exhibited better glucose control and marked reduction in body weight and hepatic lipid accumulation. Thus, these results suggest that long-term treatment with atorvastatin or the combination of atorvastatin and nicotinamide may be alternative therapies due to their beneficial effects on IR and diastolic function.

Atorvastatin attenuates TGF‑β1‑induced fibrogenesis by inhibiting Smad3 and MAPK signaling in human ventricular fibroblasts

Excessive proliferation and myofibroblasts transformation of cardiac fibroblasts play a critical role in the process of cardiac fibrosis. Atorvastatin (ATV), a 3‑hydroxy‑3‑methyl‑glutaryl‑coenzyme A reductase inhibitor, is commonly used to treat hypercholesterolemia. It has previously been shown that ATV has potential anti‑fibrotic effects. However, the underlying mechanisms of ATV against cardiac fibrosis remain to be fully elucidated, and to the best of our knowledge, there are no reports focusing on the effects of ATV on transforming growth factor‑β1 (TGF‑β1)‑induced human ventricular fibroblasts (hVFs) activation. In the present study, hVFs were stimulated with TGF‑β1 with or without pretreatment with ATV. Subsequently, hVF proliferation, cytotoxicity, myofibroblast differentiation and pro‑fibrotic gene expression were assessed. Canonical and non‑canonical signaling downstream of TGF‑β1, such as Smad3 and mitogen‑activated protein kinase (MAPK) signaling, were investigated by evaluating the phosphorylation levels of Smad3, extracellular signal‑regulated kinase 1/2, p38 MAPK and c‑Jun N‑terminal kinase. The results indicated that ATV significantly prevented TGF‑β1‑induced cell proliferation, myofibroblast differentiation and production of extracellular matrix proteins, such as matrix metalloproteinase‑2, collagen I and collagen III, in hVFs. Furthermore, ATV effectively inhibited TGF‑β1‑induced activation of Smad3 and MAPK signaling in hVFs. In conclusion, the present results demonstrated that ATV prevented TGF‑β1‑induced fibrogenesis in hVFs, at least in part by inhibiting the Smad3 and MAPK signaling pathways. Therefore, these results imply that ATV may be a promising agent to treat myocardial fibrosis.

The Pleiotropic Effects of Statins - From Coronary Artery Disease and Stroke to Atrial Fibrillation and Ventricular Tachyarrhythmia

Statins, 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors, have been used for decades for the prevention of coronary artery disease and stroke. They act primarily by lowering serum cholesterol through the inhibition of cholesterol synthesis in the liver, which results in the upregulation of low-density lipoprotein receptors in the liver. This results in the removal of low-density lipoproteincholesterol. Studies have suggested that statins may demonstrate additional effects that are independent of their effects on low-density lipoprotein-cholesterol. These have been termed "pleiotropic" effects. Pleiotropic effects may be due to the inhibition of isoprenoid intermediates by statins. Isoprenoid inhibition has effects on the small guanosine triphosphate binding proteins Rac and Rho which in turn effects nicotinamide adenine dinucleotide phosphate oxidases. Therefore, there are changes in endothelial nitric oxide synthase expression, atherosclerotic plaque stability, pro-inflammatory cytokines and reactive oxygen species production, platelet reactivity, and cardiac fibrosis and hypetrophy development. Recently, statins have been compared to the ezetimibe and the recently published outcomes data on the proprotein convertase subtilisin kexin type 9 inhibitors has allowed for a reexamination of statin pleiotropy. As a result of these diverse effects, it has been suggested that statins also have anti-arrhythmic effects. This review focuses on the mechanisms of statin pleiotropy and discusses evidence from the statin clinical trials as well as examining the possible anti-arrhythmic effects atrial fibrillation and ventricular tachyarrhythmias.

Do most patients with obesity or type 2 diabetes, and atrial fibrillation, also have undiagnosed heart failure? A critical conceptual framework for understanding mechanisms and improving diagnosis and treatment

Obesity and diabetes can lead to heart failure with preserved ejection fraction (HFpEF), potentially because they both cause expansion and inflammation of epicardial adipose tissue and thus lead to microvascular dysfunction and fibrosis of the underlying left ventricle. The same process also causes an atrial myopathy, which is clinically evident as atrial fibrillation (AF); thus, AF may be the first manifestation of HFpEF. Many patients with apparently isolated AF have latent HFpEF or subsequently develop HFpEF. Most patients with obesity or diabetes who have AF and exercise intolerance have increased left atrial pressures at rest or during exercise, even in the absence of diagnosed HFpEF. Among patients with AF, those who also have latent HFpEF have increased risk for systemic thromboembolism and death. The identification of HFpEF in patients with obesity or diabetes alters the risk-to-benefit relationship of commonly prescribed treatments. Bariatric surgery and statins can ameliorate AF and reduce the risk for HFpEF. Conversely, antihyperglycaemic drugs that promote adipogenesis or cause sodium retention (insulin and thiazolidinediones) may increase the risk for heart failure in patients with an underlying ventricular myopathy. Patients with obesity and diabetes who undergo catheter ablation for AF are at increased risk for AF recurrence and for post-ablation increases in pulmonary venous pressures and worsening heart failure, especially if HFpEF coexists. Therefore, AF may be the earliest indicator of HFpEF in patients with obesity or type 2 diabetes, and recognition of HFpEF alters the management of these patients.

AGEs impair Kv channel-mediated vasodilation of coronary arteries by activating the NF-κB signaling pathway in ZDF rats

Excessive formation of advanced glycation end products (AGEs) impairs voltage-gated potassium (Kv) channels in rat coronary artery smooth muscle cells (CSMCs), resulting in weakened Kv-mediated coronary vasodilation. We hypothesized that induction of the nuclear factor-κB (NF-κB) signaling pathway by AGEs plays a significant role in the regulation of Kv channel-mediated vasodilation in Zucker diabetic fatty (ZDF) rats. Assays of mRNA transcripts, protein expression, and intracellular localization as well as patch-clamp experiments in cultured CSMCs revealed that AGEs significantly induced activation of the NF-κB signaling pathway, reduced Kv1.2/1.5 expression, and inhibited Kv currents. In addition, silencing of the receptor for AGEs (RAGE) or p65 with siRNA and treatment with alagrebrium (ALA) or pyrrolidine dithiocarbamate (PDTC) alleviated the AGE-induced impairment of Kv channels in CSMCs. Compared with Zucker lean (ZL) rats, the amount of AGEs, RAGE protein expression, and NF-κB activity in coronary arteries were higher in ZDF rats; whereas Kv1.2/1.5 expression was significantly lower in ZDF rats. Reduced Kv1.2/1.5 expression in coronary arteries and impaired Kv-mediated coronary relaxation tested by wire myography in ZDF rats were markedly improved by treatment with aminoguanidine (AG), ALA, or PDTC. These effects were accompanied by diminished NF-κB activity, inflammation, and oxidative stress. Taken together, these results indicate that an increased interaction between AGEs and RAGE in diabetic rats leads to impaired Kv channel-mediated coronary vasodilation. Moreover, activation of the NF-κB signaling pathway and a subsequent increase of inflammation and oxidative stress may play an important role in AGE-induced impairment of coronary vasodilation in diabetes.

Pathological Role of Advanced Glycation End Products (AGEs) and their Receptor Axis in Atrial Fibrillation

Accumulating evidence has shown that the incidence of atrial fibrillation (AF) is higher in patients with diabetes, especially those with poor glycemic control or long disease duration. Nonenzymatic glycation of amino acids of proteins, lipids, and nucleic acids has progressed under normal aging process and/or diabetic condition, which could lead to the formation and accumulation of advanced glycation end products (AGEs). AGEs not only alter the tertiary structure and physiological function of macromolecules, but also evoke inflammatory and fibrotic reactions through the interaction of cell surface receptor for AGEs (RAGE), thereby being involved in aging-related disorders. In this paper, we briefly review the association of chronic hyperglycemia and type 1 diabetes with the risk of AF and then discuss the pathological role of AGE-RAGE axis in AF and its thromboembolic complications.

Specific Inhibition of CYP4A Alleviates Myocardial Oxidative Stress and Apoptosis Induced by Advanced Glycation End-Products

High exposure to advanced glycation end-products (AGEs) may induce cardiotoxicity. However, the effects and mechanisms remain to be further clarified. CYP4A plays an important role in the pathophysiological process of myocardial abnormalities by modulating oxidative stress and apoptosis (OS/Apop) signaling pathway. The present work aimed to investigate whether CYP4A mediates AGEs-induced myocardial injury. AGEs solution was administered intragastrically to C57BL/6 mice for 60 days, while the specific inhibitor of CYP4A, HET0016, was given from the 47th day via intraperitoneal injection for 2 weeks. Levels of OS/Apop in heart tissue were measured. The effects on the cell viability and apoptosis were detected in primary rat cardiomyocytes. To further investigate the mechanism, H9c2 cells were treated with HET0016 or small interfering RNAs (siRNAs) against CYP4a mRNA before incubation with AGEs. Exposure to AGEs led to significantly increased expression of CYP4A and levels of OS/Apop in heart and H9c2 cells both in vivo and in vitro. The OS/Apop pathway was activated with increased expression of NOX2, p-JNK, and cleaved caspase-3 (c-caspase-3) and decreased expression of p-Akt and Bcl-xL both in vivo and in vitro. Specific CYP4A suppression by HET0016 or siRNA exerted significant protective effects by attenuating AGEs-induced OS/Apop pathways in vitro. Our results demonstrate that specific inhibition of CYP4A might be a potential therapeutic option for myocardial injury induced by AGEs.

Impact of advanced glycation end products (AGEs) signaling in coronary artery disease

Coronary artery disease remains the leading cause of mortality in adult diabetic population with however, a high predominance also in non-diabetic subjects. In search of common molecular mechanisms and metabolic by-products with potential pathogenic role, increased advanced glycation end products (AGEs) present a critical biomarker for CAD development in both cases. Interaction of AGEs with their transmembrane cell receptor, RAGE in endothelial and smooth muscle cells as well as in platelets, activates intracellular signaling that leads to endothelial injury, modulation of vascular smooth muscle cell function and altered platelet activity. Furthermore, tissue accumulation of AGEs affects current treatment approaches being involved in stent restenosis. The present review provides an update of AGE-induced molecular mechanisms involved in CAD pathophysiology while it discusses emerging therapeutic interventions targeting AGE reduction and AGE-RAGE signaling with beneficial clinical outcome.

Isosteviol ameliorates diabetic cardiomyopathy in rats by inhibiting ERK and NF-κB signaling pathways

Diabetes-induced injury of myocardium, defined as diabetic cardiomyopathy (DCM), accounts for significant mortality and morbidity in diabetic population. Alleviation of DCM by a potent drug remains considerable interests in experimental and clinical researches because hypoglycemic drugs cannot effectively control this condition. Here, we explored the beneficial effects of isosteviol sodium (STVNa) on type 1 diabetes-induced DCM and the potential mechanisms involved. Male Wistar rats were induced to diabetes by injection of streptozotocin (STZ). One week later, diabetic rats were randomly grouped to receive STVNa (STZ/STVNa) or its vehicle (STZ). After 11 weeks of treatment or 11 weeks treatment following 4 weeks of removal of the treatment, the cardiac function and structure were evaluated and related mechanisms were investigated. In diabetic rats, oxidative stress, inflammation, blood glucose and plasma advanced glycation end products (AGEs) were significantly increased, whereas superoxide dismutase 2 (SOD-2) expression and activity were decreased. STVNa treatment inhibited cardiac hypertrophy, fibrosis and inflammation, showed similar ratio of heart to body weight and antioxidant capacities almost similar to the normal controls, which can be sustained at least 4 weeks. Moreover, STVNa inhibited diabetes-inducted stimulation of both extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) signal pathways. However, blood glucose, plasma AGE and insulin levels were not altered by STVNa treatment. These results indicate that STVNa may be developed into a potent therapy for DCM. The mechanism underlying this therapeutic effect involves the suppression of oxidative stress and inflammation by inhibiting ERK and NF-κB without changing blood glucose or AGEs.

Epicardial Adipose Tissue May Mediate Deleterious Effects of Obesity and Inflammation on the Myocardium

Epicardial adipose tissue has unique properties that distinguish it from other depots of visceral fat. Rather than having distinct boundaries, the epicardium shares an unobstructed microcirculation with the underlying myocardium, and in healthy conditions, produces cytokines that nourish the heart. However, in chronic inflammatory disorders (especially those leading to heart failure with preserved ejection fraction), the epicardium becomes a site of deranged adipogenesis, leading to the secretion of proinflammatory adipokines that can cause atrial and ventricular fibrosis. Accordingly, in patients at risk of heart failure with preserved ejection fraction, drugs that promote the accumulation or inflammation of epicardial adipocytes may lead to heart failure, whereas treatments that ameliorate the proinflammatory characteristics of epicardial fat may reduce the risk of heart failure. These observations suggest that epicardial adipose tissue is a transducer of the adverse effects of systemic inflammation and metabolic disorders on the heart, and thus, represents an important target for therapeutic interventions.

FAM3 gene family: A promising therapeutical target for NAFLD and type 2 diabetes

Non-alcoholic fatty liver disease (NAFLD) and diabetes are severe public health issues worldwide. The Family with sequence similarity 3 (FAM3) gene family consists of four members designated as FAM3A, FAM3B, FAM3C and FAM3D, respectively. Recently, there had been increasing evidence that FAM3A, FAM3B and FAM3C are important regulators of glucose and lipid metabolism. FAM3A expression is reduced in the livers of diabetic rodents and NAFLD patients. Hepatic FAM3A restoration activates ATP-P2 receptor-Akt and AMPK pathways to attenuate steatosis and hyperglycemia in obese diabetic mice. FAM3C expression is also reduced in the liver under diabetic condition. FAM3C is a new hepatokine that activates HSF1-CaM-Akt pathway and represses mTOR-SREBP1-FAS pathway to suppress hepatic gluconeogenesis and lipogenesis. In contrast, hepatic expression of FAM3B, also called PANDER, is increased under obese state. FAM3B promotes hepatic lipogenesis and gluconeogenesis by repressing Akt and AMPK activities, and activating lipogenic pathway. Under obese state, the imbalance among hepatic FAM3A, FAM3B and FAM3C signaling networks plays important roles in the pathogenesis of NAFLD and type 2 diabetes. This review briefly discussed the latest research progress on the roles and mechanisms of FAM3A, FAM3B and FAM3C in the regulation of hepatic glucose and lipid metabolism.

Matrine suppresses cardiac fibrosis by inhibiting the TGF‑β/Smad pathway in experimental diabetic cardiomyopathy

Cardiac fibrosis is one of the pathological characteristics of diabetic cardiomyopathy (DbCM). Matrine treatment has proven to be effective in cases of organ fibrosis and cardiovascular diseases. In the present study, the anti-fibrosis-associated cardioprotective effects of matrine on DbCM were investigated. Rats with experimental DbCM were administered matrine orally. Cardiac functions were evaluated using invasive hemodynamic examinations. Cardiac compliance was assessed in isolated hearts. Using Sirius Red and fluorescence staining, the collagen in diabetic hearts was visualized. MTT assay was used to select non-cytotoxic concentrations of matrine, which were subsequently used to treat isolated cardiac fibroblasts incubated under various conditions. Western blotting was performed to assess activation of the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. Rats with DbCM exhibited impaired heart compliance and left ventricular (LV) functions. Excessive collagen deposition in cardiac tissue was also observed. Furthermore, TGF-β1/R-Smad (Smad2/3) signaling was revealed to be markedly activated; however, the expression of inhibitory Smad (I-Smad, also termed Smad7) was reduced in DbCM. Matrine administration led to a marked recovery in LV function and heart compliance by exerting inhibitory effects on TGF-β1/R-Smad signaling pathway-induced fibrosis without affecting I-Smad. Incubation with a high concentration of glucose triggered the TGF-β1/R-Smad (Smad2/3) signaling pathway and suppressed I-Smad signaling transduction in cultured cardiac fibroblasts, which led to an increase in the synthesis of collagen. After cardiac fibroblasts had been treated with matrine at non-cytotoxic concentrations without affecting I-Smad, matrine blocked TGF-β1/R-Smad signaling transduction to repress collagen production and deposition. In conclusion, the results of the present study demonstrated that TGF-β1/Smad signaling-associated cardiac fibrosis is involved in the impairment of heart compliance and LV dysfunction in DbCM. By exerting therapeutic effects against cardiac fibrosis via its influence on TGF-β1/Smad signaling, matrine exhibited cardioprotective effects in DbCM.

The role of mast cells and macrophages in amiodarone induced pulmonary fibrosis and the possible attenuating role of atorvastatin

Amiodarone (AM) is an effective anti-arrhythmic drug. We investigated the role of mast cells and macrophages on AM induced pulmonary fibrosis and the action of atorvastatin on this fibrosis. Rats were allocated into four groups; negative control (1), positive control (2), 30 mg/kg body weight/day AM (3) and AM + 10 mg/kg/day atorvastatin (4). Lungs were harvested and prepared for histology and immunohistochemistry. Hematoxylin and eosin stained sections of group 3 exhibited disorganized lung architecture. We found cellular debris in the lumen of both intrapulmonary bronchi and bronchioles with partial disruption of the thickened epithelial lining and mononuclear cellular infiltration into the lamina propria. We also observed thickening of the epithelial lining and the smooth muscle layer. Congested, dilated and thickened blood capillaries and thickened inter-alveolar septa were observed with mononuclear cellular infiltrates in the lung of group 3. Most alveoli were collapsed, but some dilated ones were detected. In some alveoli, type ІІ pneumocytes were increased, while type I cells were decreased. We observed significant increases in the amount of collagen in the thickened inter-alveolar septa, around bronchioles and around blood capillaries in sections from group 3. We found a significant increase in mast cells and alveolar macrophages in group 3 compared to group 1. Mast cells and macrophages appear to play important roles in AM induced pulmonary fibrosis. Atorvastatin appears to attenuate this condition.

Novel Anti-fibrotic Therapies

Fibrosis is a major player in cardiovascular disease, both as a contributor to the development of disease, as well as a post-injury response that drives progression. Despite the identification of many mechanisms responsible for cardiovascular fibrosis, to date no treatments have emerged that have effectively reduced the excess deposition of extracellular matrix associated with fibrotic conditions. Novel treatments have recently been identified that hold promise as potential therapeutic agents for cardiovascular diseases associated with fibrosis, as well as other fibrotic conditions. The purpose of this review is to provide an overview of emerging antifibrotic agents that have shown encouraging results in preclinical or early clinical studies, but have not yet been approved for use in human disease. One of these agents is bone morphogenetic protein-7 (BMP7), which has beneficial effects in multiple models of fibrotic disease. Another approach discussed involves altering the levels of micro-RNA (miR) species, including miR-29 and miR-101, which regulate the expression of fibrosis-related gene targets. Further, the antifibrotic potential of agonists of the peroxisome proliferator-activated receptors will be discussed. Finally, evidence will be reviewed in support of the polypeptide hormone relaxin. Relaxin is long known for its extracellular remodeling properties in pregnancy, and is rapidly emerging as an effective antifibrotic agent in a number of organ systems. Moreover, relaxin has potent vascular and renal effects that make it a particularly attractive approach for the treatment of cardiovascular diseases. In each case, the mechanism of action and the applicability to various fibrotic diseases will be discussed.

Pleiotropic Effects of Statins on the Cardiovascular System

The statins have been used for 30 years to prevent coronary artery disease and stroke. Their primary mechanism of action is the lowering of serum cholesterol through inhibiting hepatic cholesterol biosynthesis thereby upregulating the hepatic low-density lipoprotein (LDL) receptors and increasing the clearance of LDL-cholesterol. Statins may exert cardiovascular protective effects that are independent of LDL-cholesterol lowering called pleiotropic effects. Because statins inhibit the production of isoprenoid intermediates in the cholesterol biosynthetic pathway, the post-translational prenylation of small GTP-binding proteins such as Rho and Rac, and their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases are also inhibited. In cell culture and animal studies, these effects alter the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, the production of proinflammatory cytokines and reactive oxygen species, the reactivity of platelets, and the development of cardiac hypertrophy and fibrosis. The relative contributions of statin pleiotropy to clinical outcomes, however, remain a matter of debate and are hard to quantify because the degree of isoprenoid inhibition by statins correlates to some extent with the amount of LDL-cholesterol reduction. This review examines some of the currently proposed molecular mechanisms for statin pleiotropy and discusses whether they could have any clinical relevance in cardiovascular disease.

Nicotinamide mononucleotide attenuates brain injury after intracerebral hemorrhage by activating Nrf2/HO-1 signaling pathway

Replenishment of NAD⁺ has been shown to protect against brain disorders such as amyotrophic lateral sclerosis and ischemic stroke. However, whether this intervention has therapeutic effects in intracerebral hemorrhage (ICH) is unknown. In this study, we sought to determine the potential therapeutic value of replenishment of NAD⁺ in ICH. In a collagenase-induced ICH (cICH) mouse model, nicotinamide mononucleotide (NMN), a key intermediate of nicotinamide adenine dinucleotide (NAD⁺) biosynthesis, was administrated at 30 minutes post cICH from tail vein to replenish NAD⁺. NMN treatment did not decrease hematoma volume and hemoglobin content. However, NMN treatment significantly reduced brain edema, brain cell death, oxidative stress, neuroinflammation, intercellular adhesion molecule-1 expression, microglia activation and neutrophil infiltration in brain hemorrhagic area. Mechanistically, NMN enhanced the expression of two cytoprotective proteins: heme oxygenase 1 (HO-1) and nuclear factor-like 2 (Nrf2). Moreover, NMN increased the nuclear translocation of Nrf2 for its activation. Finally, a prolonged NMN treatment for 7 days markedly promoted the recovery of body weight and neurological function. These results demonstrate that NMN treats brain injury in ICH by suppressing neuroinflammation/oxidative stress. The activation of Nrf2/HO-1 signaling pathway may contribute to the neuroprotection of NMN in ICH.

Matrine attenuates cardiac fibrosis by affecting ATF6 signaling pathway in diabetic cardiomyopathy

Cardiac function and compliance impairments are the features of cardiac fibrosis. Matrine shows therapeutic effects on cardiovascular diseases and organ fibrosis. In this study, we examined the therapeutic effects and mechanisms of matrine on cardiac fibrosis of DbCM. Matrine was administrated orally to rats with DbCM. Cardiac functions and compliance were evaluated. The collagen deposition was visualized by sirius red staining. Real-time PCR was used to determine the expression level of miRNA. Western blotting was performed to assess the protein expression. NFAT nuclear translocation was evaluated by fluorescent immunochemistry staining and Western blotting. Intracellular calcium level was assessed by fura-2/AM staining. A colorimetric method was used to determine calcineurin enzymatic activity. Impaired cardiac function and compliance were observed in rats with DbCM. Increased collagen deposition in cardiac tissue was found. Furthermore, ATF6 signaling was activated, leading to intracellular calcium accumulation and NFAT activation which further initiated ECM gene expressions. Matrine administration recovered cardiac function and improved compliance by exerting inhibitory effects against ATF6 signaling- induced fibrosis. The high- glucose incubation induced ATF6 signaling activation in cultured CFs to increase the synthesis of ECM. Matrine blocked the ATF6 signaling in CFs to inhibit ECM synthesis within non- cytotoxic concentrations. ATF6 signaling induced cardiac fibrosis was one of the mechanisms involved in DbCM, which was characterized by loss of cardiac compliance and functions. Matrine attenuated cardiac compliance and improved left ventricular functions by exerting therapeutic effects against cardiac fibrosis via affecting ATF6 signaling pathway.

Adiponectin Regulates the Polarization and Function of Microglia via PPAR-γ Signaling Under Amyloid β Toxicity

Alzheimer’s disease (AD), characterized by the abnormal accumulation of amyloid beta (Aβ), is gradually increasing globally. Given that AD is considered a neuroinflammatory disease, recent studies have focused on the cellular mechanisms in brain inflammatory conditions that underlie AD neuropathology. Microglia are macrophage cells in the central nervous system (CNS) that are activated in response to Aβ condition. The function of microglia contributes to the neuroinflammation in AD brain, suggesting that microglia regulate the production of inflammatory mediators and contribute to the regeneration of damaged tissues. Adiponectin, an adipokine derived from adipose tissue, has been known to regulate inflammation and control macrophages during oxidative stress conditions. In present study, we investigated whether adiponectin influences the polarization and function of microglia under Aβ toxicity by examining alterations of BV2 microglia function and polarization by Acrp30 (a globular form of adiponectin) treatment using reverse transcription PCR, western blotting and immunofluorescence staining. Acrp30 promoted the induction of the M2 phenotype, and regulated the inflammatory responses through peroxisome proliferator-activated receptor (PPAR)-γ signaling under Aβ toxicity. In addition, Acrp30 boosted the capacity of Aβ scavenging in microglia. Taken together, we suggest that adiponectin may control the function of microglia by promoting anti-inflammatory responses through PPAR- γ signaling. Hence, we conclude that adiponectin may act as a critical controller of microglia function in the AD brain.

Traditional Chinese Medication Qiliqiangxin Protects Against Cardiac Remodeling and Dysfunction in Spontaneously Hypertensive Rats

Qiliqiangxin (QLQX), a traditional Chinese herbs medication, exerted protective effect in chronic heart failure patients in a multicenter randomized double-blind study. QLQX has also been found to improve cardiac function and reduce cardiac fibrosis in spontaneously hypertension animal model. However, the effect of longterm treatment with QLQX in such a condition and the related molecular mechanisms remain largely unknown. In the present study, thirteen-week-old spontaneously hypertensive rats (SHRs) were treated by daily intragastric administration of QLQX or saline for one year. Echocardiography, electron microscopy, and Masson's trichrome staining were used to determine cardiac function, mitochondria ultrastructure, and cardiac fibrosis, respectively. Quantitative reverse transcription polymerase chain reactions (qRT-PCRs) and Western blotting were used to determine gene expressions. We found that QLQX significantly improved cardiac function and reduced gene markers of pathological hypertrophy including ANP, BNP, and Myh7. QLQX also attenuated cardiac fibrosis and apoptosis in SHRs as evidenced by downregulation of α-SMA, collagen I, collagen III, and TGF-β expressions and reduction of Bax to Bcl-2 ratio. Moreover, the damage of mitochondrial ultrastructure was greatly improved and the reduction of PPAR-α, PPAR-γ, and PGC-1α expression levels was significantly restored in SHRs by treatment with QLQX. In conclusion, longterm treatment with QLQX protects against cardiac remodeling and dysfunction in hypertension by increasing PPARs and PGC-1α.