Exenatide mitigated diet-induced vascular aging and atherosclerotic plaque growth in ApoE-deficient mice under chronic stress

New Molecules in Type 2 Diabetes: Advancements, Challenges and Future Directions

Although good glycemic control in patients with type 2 diabetes (T2D) can prevent cardiovascular complications, many diabetic patients still have poor optimal control. A new class of antidiabetic drugs (e.g., glucagon-like peptide-1-GLP-1 receptor agonists, sodium-glucose co-transporters-SGLT2 inhibitors), in addition to the low hypoglycemic effect, exert multiple beneficial effects at a metabolic and cardiovascular level, through mechanisms other than antihyperglycemic agents. This review aims to discuss the effects of these new antidiabetic drugs, highlighting cardiovascular and metabolic benefits, through the description of their action mechanisms as well as available data by preclinical and clinical studies. Moreover, new innovative tools in the T2D field will be described which may help to advance towards a better targeted T2D personalized care in future.

Long-term effects of different hypoglycemic drugs on carotid intima-media thickness progression: a systematic review and network meta-analysis

Objective

The progression of carotid intima-media thickness (cIMT) can partially predict the occurrence of future cardiovascular events. This network meta-analysis compared the effects of 14 antidiabetic drugs (acarbose, alogliptin, exenatide, glibenclamide, glimepiride, ipragliflozin, metformin, nateglinide, pioglitazone, rosiglitazone, sitagliptin, tofoglifozin, troglitazone, voglibose) on the progression of cIMT.

Method

PubMed, EMBASE, Cochrane Library, and Web of Science were searched to screen all clinical trials of treatment of cIMT with hypoglycemic agents before March 1, 2024. The differences in the changes in cIMT between the treatment group and control group were evaluated.

Result

After screening 8395 citations, 25 studies (6675 patients) were included. The results indicated that exenatide had the best efficacy in slowing down cIMT progress, and exenatide [MD=-0.13,95%CI (-0.25, -0.01)], alogliptin [MD=-0.08,95%CI (-0.13, -0.02)] and metformin [MD=-0.05, 95%CI (-0.09, -0.02)] are more effective than placebo.

Conclusion

Long-term treatment of exenatide, alogliptin, and metformin may be more effective than other hypoglycemic drugs in slowing the progression of cIMT.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024519474.

Influence of Dulaglutide on Serum Biomarkers of Atherosclerotic Plaque Instability: An Interventional Analysis of Cytokine Profiles in Diabetic Subjects-A Pilot Study

Background and Objectives: The rise in global diabetes cases, reaching a staggering 529 million in 2021 from 108 million in 1980, underscores the urgency of addressing its complications, notably macrovascular ones like coronary artery, cerebrovascular, and peripheral artery diseases, which contribute to over 50% of diabetes mortality. Atherosclerosis, linked to hyperglycemia-induced endothelial dysfunction, is pivotal in cardiovascular disease development. Cytokines, including pentraxin 3 (PTX3), copeptin, lipoprotein(a) [Lp(a)], and matrix metalloproteinase-9 (MMP-9), influence atherosclerosis progression and plaque vulnerability. Inhibiting atherosclerosis progression is crucial, especially in diabetic individuals. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs), increasingly used for type 2 diabetes, show promise in reducing the cardiovascular risk, sparking interest in their effects on atherogenesis. This study sought to examine the effects of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on biomarkers that indicate the instability of atherosclerotic plaques. These biomarkers include pentraxin 3 (PTX3), copeptin (CPC), matrix metalloproteinase-9 (MMP-9), and lipoprotein(a) [Lp(a)]. Materials and Methods: A total of 34 participants, ranging in age from 41 to 81 years (with an average age of 61), who had been diagnosed with type 2 diabetes mellitus (with a median HbA1c level of 8.8%), dyslipidemia, and verified atherosclerosis using B-mode ultrasonography, were included in the study. All subjects were eligible to initiate treatment with a GLP-1 RA-dulaglutide. Results: Significant reductions in anthropometric parameters, blood pressure, fasting glucose levels, and HbA1c levels were observed posttreatment. Moreover, a notable decrease in biochemical markers associated with atherosclerotic plaque instability, particularly PTX3 and MMP-9 (p < 0.001), as well as Lp(a) (p < 0.05), was evident following the GLP-1 RA intervention. Conclusions: These findings underscore the potential of GLP-1 RAs in mitigating atherosclerosis progression and plaque vulnerability, thus enhancing cardiovascular outcomes in individuals with type 2 diabetes mellitus.

Cathepsin K deficiency prevented stress-related thrombosis in a mouse FeCl3 model

BACKGROUND

Exposure to chronic psychological stress (CPS) is a risk factor for thrombotic cardiocerebrovascular diseases (CCVDs). The expression and activity of the cysteine cathepsin K (CTSK) are upregulated in stressed cardiovascular tissues, and we investigated whether CTSK is involved in chronic stress-related thrombosis, focusing on stress serum-induced endothelial apoptosis.

METHODS AND RESULTS

Eight-week-old wild-type male mice (CTSK+/+) randomly divided to non-stress and 3-week restraint stress groups received a left carotid artery iron chloride3 (FeCl3)-induced thrombosis injury for biological and morphological evaluations at specific timepoints. On day 21 post-stress/injury, the stress had enhanced the arterial thrombi weights and lengths, in addition to harmful alterations of plasma ADAMTS13, von Willebrand factor, and plasminogen activation inhibitor-1, plus injured-artery endothelial loss and CTSK protein/mRNA expression. The stressed CTSK+/+ mice had increased levels of injured arterial cleaved Notch1, Hes1, cleaved caspase8, matrix metalloproteinase-9/-2, angiotensin type 1 receptor, galactin3, p16IN4A, p22phox, gp91phox, intracellular adhesion molecule-1, TNF-α, MCP-1, and TLR-4 proteins and/or genes. Pharmacological and genetic inhibitions of CTSK ameliorated the stress-induced thrombus formation and the observed molecular and morphological changes. In cultured HUVECs, CTSK overexpression and silencing respectively increased and mitigated stressed-serum- and H2O2-induced apoptosis associated with apoptosis-related protein changes. Recombinant human CTSK degraded γ-secretase substrate in a dose-dependent manor and activated Notch1 and Hes1 expression upregulation.

CONCLUSIONS

CTSK appeared to contribute to stress-related thrombosis in mice subjected to FeCl3 stress, possibly via the modulation of vascular inflammation, oxidative production and apoptosis, suggesting that CTSK could be an effective therapeutic target for CPS-related thrombotic events in patients with CCVDs.

GLP-1 receptor agonists and atherosclerosis protection: the vascular endothelium takes center stage

Atherosclerotic cardiovascular disease is a chronic condition that often copresents with type 2 diabetes and obesity. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetics endorsed by major professional societies for improving glycemic status and reducing atherosclerotic risk in people living with type 2 diabetes. Although the cardioprotective efficacy of GLP-1RAs and their relationship with traditional risk factors are well established, there is a paucity of publications that have summarized the potentially direct mechanisms through which GLP-1RAs mitigate atherosclerosis. This review aims to narrow this gap by providing comprehensive and in-depth mechanistic insight into the antiatherosclerotic properties of GLP-1RAs demonstrated across large outcome trials. Herein, we describe the landmark cardiovascular outcome trials that triggered widespread excitement around GLP-1RAs as a modern class of cardioprotective agents, followed by a summary of the origins of GLP-1RAs and their mechanisms of action. The effects of GLP-1RAs at each major pathophysiological milestone of atherosclerosis, as observed across clinical trials, animal models, and cell culture studies, are described in detail. Specifically, this review provides recent preclinical and clinical evidence that suggest GLP-1RAs preserve vessel health in part by preventing endothelial dysfunction, achieved primarily through the promotion of angiogenesis and inhibition of oxidative stress. These protective effects are in addition to the broad range of atherosclerotic processes GLP-1RAs target downstream of endothelial dysfunction, which include systemic inflammation, monocyte recruitment, proinflammatory macrophage and foam cell formation, vascular smooth muscle cell proliferation, and plaque development.

GLP1 Receptor Agonists-Effects beyond Obesity and Diabetes

Glucagon-like peptide-1 receptor agonists (GLP1RA) have been transformative for patients and clinicians in treating type-2 diabetes and obesity. Drugs of this class, the bioavailability of which is continuously improving, enable weight loss and control blood glucose with minimal unwanted side effects. Since adopting GLP1RA for treating metabolic diseases, animal and clinical studies have revealed their beneficial effects on several other pathologies, including cardiovascular diseases, neurodegeneration, kidney disease, and cancer. A notable commonality between these diseases is their association with older age. Clinical trials and preclinical data suggest that GLP1RA may improve outcomes in these aging-related diseases. Some of the benefits of GLP1RA may be indirect due to their effects on obesity and glucose metabolism. However, there is building evidence that GLP1RA may also act directly on multiple organs implicated in aging-related pathology. This review aims to compile the studies reporting the effects of GLP1RA on aging-related diseases and discuss potential underlying mechanisms.

Epigenetic modulation of Drp1-mediated mitochondrial fission by inhibition of S-adenosylhomocysteine hydrolase promotes vascular senescence and atherosclerosis

AIMS

Vascular senescence, which is closely related to epigenetic regulation, is an early pathological condition in cardiovascular diseases including atherosclerosis. Inhibition of S-adenosylhomocysteine hydrolase (SAHH) and the consequent increase of S-adenosylhomocysteine (SAH), a potent inhibitor of DNA methyltransferase, has been associated with an elevated risk of cardiovascular diseases. This study aimed to investigate whether the inhibition of SAHH accelerates vascular senescence and the development of atherosclerosis.

METHODS AND RESULTS

The case-control study related to vascular aging showed that increased levels of plasma SAH were positively associated with the risk of vascular aging, with an odds ratio (OR) of 3.90 (95% CI, 1.17-13.02). Elevated pulse wave velocity, impaired endothelium-dependent relaxation response, and increased senescence-associated β-galactosidase staining were observed in the artery of SAHH+/- mice at 32 weeks of age. Additionally, elevated expression of p16, p21, and p53, fission morphology of mitochondria, and over-upregulated expression of Drp1 were observed in vascular endothelial cells with SAHH inhibition in vitro and in vivo. Further downregulation of Drp1 using siRNA or its specific inhibitor, mdivi-1, restored the abnormal mitochondrial morphology and rescued the phenotypes of vascular senescence. Furthermore, inhibition of SAHH in APOE-/- mice promoted vascular senescence and atherosclerosis progression, which was attenuated by mdivi-1 treatment. Mechanistically, hypomethylation over the promoter region of DRP1 and downregulation of DNMT1 were demonstrated with SAHH inhibition in HUVECs.

CONCLUSIONS

SAHH inhibition epigenetically upregulates Drp1 expression through repressing DNA methylation in endothelial cells, leading to vascular senescence and atherosclerosis. These results identify SAHH or SAH as a potential therapeutic target for vascular senescence and cardiovascular diseases.

Overview of multifunctional cysteinyl cathepsins in atherosclerosis-based cardiovascular disease: from insights into molecular functions to clinical implications

Cysteinyl cathepsins (CTSs) are widely known to have a proteolysis function that mediates recycling of unwanted proteins in endosomes and lysosomes, and investigation of CTSs has greatly improved with advances in live-imaging techniques both in vivo and in vitro, leading to three key findings. (1) CTSs are relocated from the lysosomes to other cellular spaces (i.e., cytosol, nucleus, nuclear membrane, plasma membrane, and extracellular milieu). (2) In addition to acidic cellular compartments, CTSs also exert biological activity in neutral environments. (3) CTSs also exert multiple nontraditional functions in, for example, extracellular matrix metabolism, cell signaling transduction, protein processing/trafficking, and cellular events. Various stimuli regulate the expression and activities of CTSs in vivo and vitro-e.g., inflammatory cytokines, oxidative stress, neurohormones, and growth factors. Accumulating evidence has confirmed the participation of CTSs in vascular diseases characterized by atherosclerosis, plaque rupture, thrombosis, calcification, aneurysm, restenosis/in-stent-restenosis, and neovasel formation. Circulating and tissue CTSs are promising as biomarkers and as a diagnostic imaging tool in patients with atherosclerosis-based cardiovascular disease (ACVD), and pharmacological interventions with their specific and non-specific inhibitors, and cardiovascular drugs might have potential for the therapeutic targeting of CTSs in animals. This review focuses on the update findings on CTS biology and the involvement of CTSs in the initiation and progression of ACVD and discusses the potential use of CTSs as biomarkers and small-molecule targets to prevent deleterious nontraditional functions in ACVD.

Cathepsin K Deficiency Prevented Kidney Damage and Dysfunction in Response to 5/6 Nephrectomy Injury in Mice With or Without Chronic Stress

Background:

Chronic psychological stress is a risk factor for kidney disease, including kidney dysfunction and hypertension. Lysosomal CatK (cathepsin K) participates in various human pathobiologies. We investigated the role of CatK in kidney remodeling and hypertension in response to 5/6 nephrectomy injury in mice with or without chronic stress.

Methods:

Male 7-week-old WT (wild type; CatK^+/+) and CatK-deficient (CatK^−/−) mice that were or were not subjected to chronic stress underwent 5/6 nephrectomy. At 8 weeks post-stress/surgery, the stress was observed to have accelerated injury-induced glomerulosclerosis, proteinuria, and blood pressure elevation.

Results:

Compared with the nonstressed mice, the stressed mice showed increased levels of TLR (Toll-like receptor)-2/4, p22^phox, gp91^phox, CatK, MMP (matrix metalloproteinase)-2/9, collagen type I and III genes, PPAR-γ (peroxisome proliferator-activated receptor-gamma), NLRP-3 (NOD-like receptor thermal protein domain associated protein 3), p21, p16, and cleaved caspase-8 proteins, podocyte foot process effacement, macrophage accumulation, apoptosis, and decreased levels of Bcl-2 (B cell lymphoma 2) and Sirt1, as well as decreased glomerular desmin expression in the kidneys. These harmful changes were retarded by the genetic or pharmacological inhibition of CatK. Consistently, CatK inhibition ameliorated 5/6 nephrectomy–related kidney injury and dysfunction. In mesangial cells, CatK silencing or overexpression, respectively, reduced or increased the PPAR-γ and cleaved caspase-8 protein levels, providing evidence and a mechanistic explanation of CatK’s involvement in PPAR-γ/caspase-8–mediated cell apoptosis in response to superoxide and stressed serum.

Conclusions:

These results demonstrate that CatK plays an essential role in kidney remodeling and hypertension in response to 5/6 nephrectomy or stress, possibly via a reduction of glomerular inflammation, apoptosis, and fibrosis, suggesting a novel therapeutic strategy for controlling kidney injury in mice under chronic psychological stress conditions.

The anti-inflammatory and immunological properties of GLP-1 Receptor Agonists

In the last few years, a great interest has emerged in investigating the pleiotropic effects of Glucagon Like Peptide-1 Receptor Agonists (GLP-1RAs). While GLP-1RAs ability to lower plasma glucose and to induce weight loss has allowed them to be approved for the treatment of diabetes and obesity, consistent evidences from in vitro studies and preclinical models suggested that GLP-1RAs have anti-inflammatory properties and that may modulate the immune-system. Notably, such anti-inflammatory effects target different pathways in different tissues, underling the broad spectrum of GLP-1RAs actions. This review examines some of the currently proposed molecular mechanisms of GLP-1RAs actions and explores their potential benefits in reducing inflammatory responses, which may well suggest a future therapeutic use of GLP-1RAs in new indications.

Stem Cell-derived Exosomal MicroRNA as Therapy for Vascular Age-related Diseases

Vascular age-related diseases describe a group of age-related chronic diseases that result in a considerable healthcare burden to society. Vascular aging includes structural changes and dysfunctions of endothelial cells (ECs) and smooth muscle cells (SMCs) in blood vessels. Compared with conventional treatment for vascular age-related diseases, stem cell (SC) therapy elicits better anti-aging effects viathe inhibition/delay ECs and SMCs from entering senescence. Exosomal noncoding RNA (ncRNAs) in vascular aging and stem cell-derived exosomal microRNAs (SCEV-miRNAs), especially in mesenchymal stem cells, have an important role in the development of age-related diseases. This review summarizes SCEV-miRNAs of diverse origins that may play a vital role in treating subclinical and clinical stages of vascular age-related disorders. We further explored possible age-related pathways and molecular targets of SCEV-miRNA, which are associated with dysfunctions of ECs and SMCs in the senescent stage. Moreover, the perspectives and difficulties of SCEV-miRNA clinical translation are discussed. This review aims to provide greater understanding of the biology of vascular aging and to identify critical therapeutic targets for SCEV-miRNAs. Though still in its infancy, the potential value of SCEV-miRNAs for vascular age-related diseases is clear.

Recent Progress of Chronic Stress in the Development of Atherosclerosis

With the development of the times, cardiovascular diseases have become the biggest cause of death in the global aging society, causing a serious social burden. Atherosclerosis is a chronic inflammatory disease, which can occur in large and medium-sized blood vessels in the whole body. It takes atherosclerotic plaque as the typical pathological change and endothelial injury as the core pathophysiological mechanism. It is the pathological basis of coronary heart disease, peripheral artery disease, cerebrovascular disease, and other diseases. Recent studies have shown that chronic stress plays an important role in the occurrence and development of atherosclerosis, endothelial injury, lipid metabolism, and chronic inflammation. This process involves a large number of molecular targets. It is usually the cause of atherosclerotic cardiovascular and cerebrovascular diseases. If chronic stress factors exist for a long time, patients have genetic susceptibility, and the combination of environmental factors triggers the pathogenesis, which may eventually lead to complete blockage of the blood vessels, unstable rupture of plaques, and serious adverse cardiovascular events. This paper reviews the role of chronic stress in the occurrence and development of atherosclerosis, focusing on the pathophysiological mechanism.

Chronic Stress A Potential Suspect Zero of Atherosclerosis: A Systematic Review

Atherosclerosis (AS) is a chronic vascular inflammatory disease, in which the lipid accumulation in the intima of the arteries shows yellow atheromatous appearance, which is the pathological basis of many diseases, such as coronary artery disease, peripheral artery disease and cerebrovascular disease. In recent years, it has become the main cause of death in the global aging society, which seriously endangers human health. As a result, research on AS is increasing. Lesions of atherosclerosis contain macrophages, T cells and other cells of the immune response, together with cholesterol that infiltrates from the blood. Recent studies have shown that chronic stress plays an important role in the occurrence and development of AS. From the etiology of disease, social, environmental and genetic factors jointly determine the occurrence of disease. Atherosclerotic cardio-cerebrovascular disease (ASCVD) is often caused by chronic stress (CS). If it cannot be effectively prevented, there will be biological changes in the body environment successively, and then the morphological changes of the corresponding organs. If the patient has a genetic predisposition and a combination of environmental factors triggers the pathogenesis, then chronic stress can eventually lead to AS. Therefore, this paper discusses the influence of chronic stress on AS in the aspects of inflammation, lipid metabolism, endothelial dysfunction, hemodynamics and blood pressure, plaque stability, autophagy, ferroptosis, and cholesterol efflux.

Saxagliptin ameliorated the depressive-like behavior induced by chronic unpredictable mild stress in rats: Impact on incretins and AKT/PI3K pathway

Depression is a widespread, withering illness, resulting in a massive personal suffering and economic loss. The chronic exposure to stress may be involved in the etiology of human psychiatric disorders; such as depression. In the current study, the animals were subjected to chronic unpredictable mild stress (CUMS) for 14 days. Saxagliptin (SAXA) is a member of dipeptidyl peptidase-4 (DPP-4) inhibitors class. The current study was the first one to examine the anti-depressive effect of SAXA in an experimental model of CUMS-induced depression in rats and the possible underlying mechanisms. Animals were orally treated with SAXA (0.5, 1 and 2 mg/kg) for 14 days. SAXA treatment reversed the CUMS-induced alterations in the behavioral, biochemical as well as histopathological parameters. Moreover, it hindered the CUMS-induced increase in the oxidative stress, inflammatory, and apoptotic markers. On the other hand, it increased the monoamines levels and the neurogenic brain derived neurotrophic factor (BDNF). In addition, SAXA treatment increased the incretin hormones, glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), which are linked to the activation of protein kinase B (AKT)/phosphatidylinositol3-kinase (PI3K) pathway. In conclusion, the current study revealed that the modulation of the interplay between the key events involved in depression, including oxidative stress, inflammation, and GLP-1/PI3K/AKT signaling pathway, can explain the anti-depressant activity of SAXA.

What Is the Mechanism Driving the Reduction of Cardiovascular Events from Glucagon-like Peptide-1 Receptor Agonists?-A Mini Review

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are considered the standard of care for type 2 diabetes in many countries worldwide. These molecules have profound anti-hyperglycaemic actions with a favourable safety profile. They are now being considered for their robust cardiovascular (CV) protective qualities in diabetic patients. Most recent CV outcome trials have reported that GLP-1 RAs reduce major adverse cardiovascular events (MACE). Furthermore, the GLP-1 RAs seem to target the atherosclerotic CV disease processes preferentially. GLP-1 RAs also improve a wide range of routinely measured surrogate markers associated with CV risk. However, mediation analysis suggests these modest improvements may contribute indirectly to the overall anti-atherogenic profile of the molecules but fall short in accounting for the significant reduction in MACE. This review explores the body of literature to understand the possible mechanisms that contribute to the CV protective profile of GLP-1 RAs.

Statins Mitigate Stress-Related Vascular Aging and Atherosclerosis in apoE-Deficient Mice Fed High Fat-Diet: The Role of Glucagon-Like Peptide-1/Adiponectin Axis

Objectives

Exposure to chronic psychosocial stress is a risk factor for atherosclerotic cardiovascular diseases. Given that the 3-hydroxy-3-methylglutaryl-coenzyme reductase inhibitor statins prevent atherogenesis, we evaluated whether pitavastatin prevents chronic stress- and high fat diet-induced vascular senescence and atherogenesis in apolipoprotein E-deficient (ApoE^–/–) mice, with a special focus on glucagon-like peptide-1 (GLP-1)/adiponectin (APN) axis.

Methods and Results

6-week-old ApoE^–/– mice loaded a high-fat diet were randomly assigned into non-stress (n = 12) and stress (n = 13) groups for 12 weeks. Non-stress control mice were left undisturbed. Chronic stress accelerated high fat diet-induce arterial senescence and atherosclerotic plaque growth. The chronic stress lowered the levels of circulating GLP-1 as well as adipose and plasma APN. As compared with the stress alone mice, the pitavastatin-treated mice had reduced macrophage infiltration, elastin fragments, and increased plaque collagen volume, and lowered levels of osteopontin, toll-like receptor-2/-4, macrophage chemoattractant protein-1, C-X-C chemokine receptor-4, p47^phox, p47^phox, gp91^phox, cathepsins S, p16, and p21, mRNAs and/or proteins. Pitavastatin increased plasma GLP-1 and APN levels and suppressed matrix metalloproteinase-2/-9 gene expressions and activities in the aortas. Finally, the protective effect of pitavastatin was abrogated by APN blocking.

Conclusion

These findings suggested that the pitavastatin-mediated pleiotropic vasculoprotective effects are likely attributable, at least in part, to the elevation of GLP-1 and APN levels and the inhibition of diet-induced plaque inflammation, oxidative stress, and proteolysis in ApoE^–/– mice received chronic stress conditions.

Dipeptidyl peptidase-4 inhibition prevents lung injury in mice under chronic stress via the modulation of oxidative stress and inflammation

Exposure to chronic psychosocial stress is a risk factor for various pulmonary diseases. In view of the essential role of dipeptidyl peptidase 4 (DPP4) in animal and human lung pathobiology, we investigated the role of DPP4 in stress-related lung injury in mice. Eight-week-old male mice were randomly divided into a non-stress group and a 2-week immobilization stress group. Non-stress control mice were left undisturbed. The mice subjected to immobilized stress were randomly assigned to the vehicle or the DPP4 inhibitor anagliptin for 2 weeks. Chronic stress reduced subcutaneous and inguinal adipose volumes and increased blood DPP4 levels. The stressed mice showed increased levels in the lungs of genes and/or proteins related to oxidative stress (p67^phox, p47^phox, p22^phox and gp91^phox), inflammation (monocyte chemoattractant protein-1, vascular cell adhesion molecule-1, and intracellular adhesion molecule-1), apoptosis (caspase-3, -8, -9), senescence (p16^INK4A, p21, and p53) and proteolysis (matrix metalloproteinase-2 to -9, cathepsin S/K, and tissue inhibitor of matrix metalloproteinase-1 and -2), and reduced levels of eNOS, Sirt1, and Bcl-2 proteins; and these effects were reversed by genetic and pharmacological inhibitions of DPP4. We then exposed human umbilical vein endothelial cells in vitro to hydrogen peroxide; anagliptin treatment was also observed to mitigate oxidative and inflammatory molecules in this setting. Anagliptin can improve lung injury in stressed mice, possibly by mitigating vascular inflammation, oxidative stress production, and proteolysis. DPP4 may become a new therapeutic target for chronic psychological stress-related lung disease in humans and animals.

Deficiency of cysteinyl cathepsin K suppresses the development of experimental intimal hyperplasia in response to chronic stress

BACKGROUND

Chronic psychological stress (CPS) is linked to cardiovascular disease initiation and progression. Given that cysteinyl cathepsin K (CatK) participates in vascular remodeling and atherosclerotic plaque growth in several animal models, we investigated the role of CatK in the development of experimental neointimal hyperplasia in response to chronic stress.

METHODS AND RESULTS

At first, male wild-type (CatK) mice that underwent carotid ligation injury were subjected to chronic immobilization stress. On postoperative and stressed day 14, the results demonstrated that stress accelerated injury-induced neointima hyperplasia. On day 4, stressed mice showed following: increased levels of monocyte chemoattractant protein-1, gp91phox, toll-like receptor-2 (TLR2), TLR4, and CatK mRNAs or/and proteins, oxidative stress production, aorta-derived smooth muscle cell (SMC) migration, and macrophage infiltration as well as targeted intracellular proliferating-related molecules. Stressed mice showed increased matrix metalloproteinase-2 (MMP-2) and MMP-9 mRNA expressions and activities and elastin disruption in the injured carotid arteries. Second, CatK and CatK deficiency (CatK) mice received ligation injury and stress to explore the role of CatK. The stress-induced harmful changes were prevented by CatK. Finally, CatK mice that had undergone ligation surgery were randomly assigned to one of two groups and administered vehicle or CatK inhibitor for 14 days. Pharmacological CatK intervention produced a vascular benefit.

CONCLUSION

These data indicate that CatK deletion protects against the development of experimental neointimal hyperplasia via the attenuation of inflammatory overaction, oxidative stress production, and VSMC proliferation, suggesting that CatK is a novel therapeutic target for the management of CPS-related restenosis after intravascular intervention therapies.

Increased dipeptidyl peptidase-4 accelerates chronic stress-related thrombosis in a mouse carotid artery model

OBJECTIVE

Exposure to chronic psychosocial stress is a risk factor for metabolic cardiovascular disorders. Given that dipeptidyl peptidase-4 (DPP-4) has an important role in human pathobiology, we investigated the role of DPP-4 in stress-related thrombosis in mice, focusing on oxidative stress and the von Willebrand factor (vWF)-cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13).

METHODS AND RESULTS

Male mice randomly assigned to nonstress and 2-week immobilized-stress groups underwent iron chloride3 (FeCl3)-induced carotid artery thrombosis surgery for morphological and biochemical studies at specific times. On day 14 post-stress/surgery, stress had enhanced the lengths and weights of arterial thrombi, with alterations of plasma DPP-4, plasminogen activation inhibitor-1 and ADAMTS13. The stressed mice had increased levels of vascular cell adhesion molecule-1, intracellular adhesion molecule-1, monocyte chemoattractant protein-1, gp91phox, p22phox, matrix metalloproteinase-2 (MMP-2), MMP-9, cathepsins S and K mRNAs and/or proteins, and reduced levels of endothelial nitric oxide synthase, catalase and superoxide dismutase-1 mRNAs and/or proteins. Stress also accelerated arterial endothelial cell damage. The DPP-4 inhibitor anagliptin ameliorated the stress-induced targeted molecular and morphological changes and thrombosis. In vitro, DPP-4 inhibition also mitigated the alterations in the targeted ADAMTS13 and other oxidative and inflammatory molecules in human umbilical vein endothelial cells in response to H2O2.

CONCLUSION

DPP-4 inhibition appeared to improve the FeCl3-induced thrombosis in mice that received stress, possibly via the improvement of ADAMTS13 and oxidative stress, suggesting that DPP-4 could become a novel therapeutic target for chronic psychological stress-related thrombotic events in metabolic cardiovascular disorders.

Role of Dipeptidyl Peptidase-4 in Atherosclerotic Cardiovascular Disease in Humans and Animals with Chronic Stress

Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular atherosclerosis-based cardiovascular disease (ACVD). Dipeptidyl peptidase-4 (DPP-4) is a complex enzyme that acts as a membrane-anchored cell surface exopeptidase. DPP-4 is upregulated in metabolic and inflammatory cardiovascular disorders. DPP-4 exhibits many physiological and pharmacological functions by regulating its extremely abundant substrates, such as glucagon-like peptide-1 (GLP-1). Over the last 10 years, emerging data have demonstrated unexpected roles of DPP-4 in extracellular and intracellular signaling, immune activation, inflammation, oxidative stress production, cell apoptosis, insulin resistance, and lipid metabolism. This mini-review focuses on recent novel findings in this field, highlighting a DPP-4-mediated regulation of GLP-1-dependent and -independent signaling pathways as a potential therapeutic molecular target in treatments of chronic psychological stress-related ACVD in humans and animals.

GLP-1 receptor agonists (GLP-1RAs): cardiovascular actions and therapeutic potential

Type 2 diabetes mellitus (T2DM) is closely associated with cardiovascular diseases (CVD), including atherosclerosis, hypertension and heart failure. Some anti-diabetic medications are linked with an increased risk of weight gain or hypoglycemia which may reduce the efficacy of the intended anti-hyperglycemic effects of these therapies. The recently developed receptor agonists for glucagon-like peptide-1 (GLP-1RAs), stimulate insulin secretion and reduce glycated hemoglobin levels without having side effects such as weight gain and hypoglycemia. In addition, GLP1-RAs demonstrate numerous cardiovascular protective effects in subjects with or without diabetes. There have been several cardiovascular outcomes trials (CVOTs) involving GLP-1RAs, which have supported the overall cardiovascular benefits of these drugs. GLP1-RAs lower plasma lipid levels and lower blood pressure (BP), both of which contribute to a reduction of atherosclerosis and reduced CVD. GLP-1R is expressed in multiple cardiovascular cell types such as monocyte/macrophages, smooth muscle cells, endothelial cells, and cardiomyocytes. Recent studies have indicated that the protective properties against endothelial dysfunction, anti-inflammatory effects on macrophages and the anti-proliferative action on smooth muscle cells may contribute to atheroprotection through GLP-1R signaling. In the present review, we describe the cardiovascular effects and underlying molecular mechanisms of action of GLP-1RAs in CVOTs, animal models and cultured cells, and address how these findings have transformed our understanding of the pharmacotherapy of T2DM and the prevention of CVD.

High-mobility group box 1 serves as an inflammation driver of cardiovascular disease

Cardiovascular disease (CVD) is the most deadly disease, which can cause sudden death, in which inflammation is a key factor in its occurrence and development. High-mobility group box 1 (HMGB1) is a novel nuclear DNA-binding protein that activates innate immunity to induce inflammation in CVD. HMGB1 exists in the cytoplasm and nucleus of different cell types, including those in the heart. By binding to its receptors, HMGB1 triggers a variety of signaling cascades, leading to inflammation and CVD. To help develop HMGB1-targeted therapies, here we discuss HMGB1 and its biological functions, receptors, signaling pathways, and pathophysiology related to inflammation and CVD, including cardiac remodeling, cardiac hypertrophy, myocardial infarction, heart failure, pulmonary hypertension, atherosclerosis, and cardiomyopathy.

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, attenuates apoptosis of vascular smooth muscle cells and reduces atherosclerosis in diabetic apolipoprotein E-deficient mice

Sitagliptin, a dipeptidyl peptidase-4(DPP-4) Inhibitor, has been found to have an anti-atherosclerotic effect. Since apoptosis of vascular smooth muscle cells (VSMCs) contributes to the occurrence of diabetic atherosclerosis. This study aimed to examine whether sitagliptin suppresses the atherosclerosis progression to hyperglycemia in a low-dose streptozotocin (STZ)-induced diabetic mouse model, and then investigated the effect of sitagliptin on VSMCs apoptosis and its underlying mechanism. In vivo studies, eight-week-old low-dose STZ-induced diabetic apolipoprotein E (apoE)-deficient (apoE-/-) mice fed a high-fat diet were administered a DPP-4 inhibitor, sitagliptin, 200 mg/kg/day, or Lantus insulin by daily subcutaneous injection of 1 unit/mouse over a period of 12 weeks. Aortic atherosclerosis and apoptosis in the plaque were determined using dUTP-biotin nick end labeling (TUNEL) staining and immunohistochemistry. In vitro studies utilized the VSMCs for determination of glucagon-like peptide 1 receptor (GLP-1R) and DPP-4 expression and flow cytometry and Western blotting were used to determine apoptosis and protein expression, respectively. Sitagliptin significantly reduced atherosclerotic lesion area (7.00 ± 0.13 vs. 12.80 ± 2.7%, p = 0.003) and suppressed vascular smooth muscle cell apoptosis (2.30 ± 1.34 vs. 4.8 ± 1.93%, p = 0.003) compared with vehicle treatment. In addition, sitagliptin significantly increased the expression of β-catenin in the aortic tissue(0.56 ± 0.13 vs.0.17 ± 0.02, p = 0.008)compared with vehicle treatment. In cultured mouse VSMCs, sitagliptin enhanced GLP-1 activity significantly retarded oxidative stress (H₂O₂)-induced apoptosis compared with GLP-1 or sitagliptin alone. Sitagliptin increased GLP-1-induced cytosolic levels of β-catenin compared with GLP-1 alone, resulted in increasing the expression of survivin, and suppressed proinflammatory cytokines, i.e., interleukin-6(IL-6) and tumor necrosis factor-alpha(TNF-α), production in response to H₂O₂. In conclusion, these results indicated that the anti-atherosclerotic effect of sitagliptin is mediated, at least in part, by its inhibition of VSMCs apoptosis.

Linagliptin mitigates experimental inflammatory bowel disease in rats by targeting inflammatory and redox signaling

AIMS

Dipeptidyl peptidase-4 (DPP-4) has been involved in the pathogenesis of inflammatory bowel diseases (IBD), yet the underlying mechanisms remain inconclusive. The present study aimed to investigate the potential of linagliptin, a potent/selective DPP-4 inhibitor with marked anti-inflammatory actions, to attenuate trinitrobenzene sulfonic acid (TNBS)-evoked colitis in rats; an experimental model of IBD, and the implicated molecular mechanisms. This may add to the clinical utility of linagliptin for the management of patients with coexisting IBD and diabetes mellitus. Notably, no former studies have linked JAK2/STAT3, HMGB1/NF-κB, and Nrf2/HO-1 signaling in TNBS-evoked colitis.

MATERIALS AND METHODS

Western blotting and ELISA were used to determine the levels of target signals.

KEY FINDINGS

Administration of linagliptin (1.5 mg/kg; p.o.) mitigated the colitis severity via diminishing the disease activity index, colon weight/length ratio, and macroscopic scores. Linagliptin also lowered the colonic histologic scores and leukocyte invasion. Notably, linagliptin inhibited the colonic DPP-4 activity and upregulated the expression of intestinotrophic GLP-2 without incurring hypoglycemia in animals. Linagliptin curbed inflammation through the suppression of colonic IL-6, TNF-α, and myeloperoxidase and upregulation of IL-10. It also inhibited the IL-6/JAK2/STAT3 pathway via downregulating p-JAK2/JAK2 and p-STAT3/STAT3 protein expression and HMGB1/RAGE/NF-κB cascade through lowering HMGB1, RAGE, and p-NF-κB p65/NF-κB p65 protein expression. In the context of mucosal oxidative stress, linagliptin diminished lipid peroxides and augmented GSH, GPx, and total antioxidant capacity. It also activated Nrf2/HO-1 pathway via upregulating Nrf2 and HO-1 protein expression.

SIGNIFICANCE

Linagliptin shows a promise for the management of IBD via targeting IL-6/JAK2/STAT3, HMGB1/RAGE/NF-κB, and Nrf2/HO-1 pathways.

Therapies for the Treatment of Cardiovascular Disease Associated with Type 2 Diabetes and Dyslipidemia

Cardiovascular disease (CVD) is the leading cause of death worldwide and is the clinical manifestation of the atherosclerosis. Elevated LDL-cholesterol levels are the first line of therapy but the increasing prevalence in type 2 diabetes mellitus (T2DM) has positioned the cardiometabolic risk as the most relevant parameter for treatment. Therefore, the control of this risk, characterized by dyslipidemia, hypertension, obesity, and insulin resistance, has become a major goal in many experimental and clinical studies in the context of CVD. In the present review, we summarized experimental studies and clinical trials of recent anti-diabetic and lipid-lowering therapies targeted to reduce CVD. Specifically, incretin-based therapies, sodium-glucose co-transporter 2 inhibitors, and proprotein convertase subtilisin kexin 9 inactivating therapies are described. Moreover, the novel molecular mechanisms explaining the CVD protection of the drugs reviewed here indicate major effects on vascular cells, inflammatory cells, and cardiomyocytes, beyond their expected anti-diabetic and lipid-lowering control. The revealed key mechanism is a prevention of acute cardiovascular events by restraining atherosclerosis at early stages, with decreased leukocyte adhesion, recruitment, and foam cell formation, and increased plaque stability and diminished necrotic core in advanced plaques. These emergent cardiometabolic therapies have a promising future to reduce CVD burden.

Association of Circulating Cathepsin S and Cardiovascular Disease Among Patients With Type 2 Diabetes: A Cross-Sectional Community-Based Study

BACKGROUND

Cathepsin S, as an adipokine, was reported to play a critical role in various disease, including atherosclerosis and diabetes. The present study aims to elucidate the relationship between circulating cathepsin S and cardiovascular disease (CVD) in patients with type 2 diabetes.

METHODS

A total of 339 type 2 diabetes individuals were enrolled in this cross-sectional community-based study. Basic information, medical and laboratory data were collected. Serum cathepsin S levels were assessed by ELISA.

RESULTS

Compared to the CVD (-) group, levels of serum cathepsin S were significantly higher in the CVD (+) group, with the median 23.68 ng/ml (18.54-28.02) and 26.81 ng/ml (21.19-37.69) respectively (P < 0.001). Moreover, patients with acute coronary syndrome (ACS) had substantially higher levels of serum cathepsin S than those with stable angina pectoris (SAP), with the median 34.65 ng/ml (24.33-42.83) and 25.52 ng/ml (20.53-31.47) respectively (P < 0.01). The spearman correlation analysis showed that circulating cathepsin S was correlated with several cardiovascular risk factors. The univariate and multivariate logistic regression analysis revealed that circulating cathepsin S was an independent risk factor for CVD (all P < 0.001) after adjustment for potential confounders. Restricted cubic spline analysis showed circulating cathepsin S had a linearity association with CVD. In addition, receiver operating characteristic (ROC) curve analysis demonstrated that the area under curve (AUC) values of cathepsin S was 0.80 (95% CI: 0.75-0.84, P < 0.001), with the optimal cutoff value of cathepsin 26.28 ng/ml.

CONCLUSION

Circulating cathepsin S was significantly higher in the CVD (+) group than that in the CVD (-) one among type 2 diabetes. The increased serum cathepsin S levels were associated with increased risks of CVD, even after adjusting for potential confounders. Thus, cathepsin S might be a potential diagnostic biomarker for CVD.

Exenatide inhibits necrosis by enhancing angiogenesis and ameliorating ischemia/reperfusion injury in a random skin flap rat model

BACKGROUND

Random skin flaps are often used for plastic repair because they are convenient and flexible. However, necrosis of flaps is a common complication that may lead to disastrous consequences. Exenatide, a glucagon-like peptide 1 receptor agonist, can enhance angiogenesis and ameliorate ischemia/reperfusion injury. Our experiments explored random skin flap outcomes after its use.

METHODS

We established modified dorsal McFarlane flaps on 54 Sprague-Dawley rats and divided the rats into three groups (control, Exe-I, and Exe-II). We intraperitoneally injected either 4 or 8 μg/kg/day exenatide into the rats of the Exe-I and Exe-II groups, respectively. On the seventh day after the operation, we measured the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Tissue sections were obtained for histopathological and immunohistochemical analyses, and we evaluated the expression of vascular endothelial growth factor (VEGF), interleukin (IL) 6, IL-1β, nuclear factor kappa beta (NF-κB), Toll-like receptor 4 (TLR4), and tumor necrosis factor α (TNF-α). We measured blood flow reconstruction and angiogenesis using laser Doppler blood flowmetry and lead oxide/gelatin angiography, respectively.

RESULTS

Exenatide increased the average survival area of the flap and improved microvascular density and blood flow intensity in a dose-dependent manner. Meanwhile, the SOD level was up-regulated and the MDA level down-regulated. Exenatide also enhanced the expression of VEGF and reduced the expression of inflammatory cytokines (IL-6, IL-1β, NF-κB, TLR4, and TNF-α), thereby promoting angiogenesis and inhibiting inflammation.

CONCLUSIONS

Exenatide potentially inhibits necrosis in our rat random skin flap model.

Increased Circulating Cathepsin L in Patients with Coronary Artery Disease

Cathepsin L (CatL) is a potent collagenase involved in atherosclerotic vascular remodeling and dysfunction in animals and humans. This study investigated the hypothesis that plasma CatL is associated with the prevalence of coronary artery disease (CAD). Between February May 2011 and January 2013, 206 consecutive subjects were enrolled from among patients who underwent coronary angiography and percutaneous coronary intervention treatment. Age-matched subjects (n = 215) served as controls. Plasma CatL and high-sensitive C-reactive protein (hs-CRP) and high-density lipoprotein cholesterol were measured. The patients with CAD had significantly higher plasma CatL levels compared to the controls (1.4 ± 0.4 versus 0.4 ± 0.2 ng/mL, P < 0.001), and the patients with acute coronary syndrome had significantly higher plasma CatL levels compared to those with stable angina pectoris (1.7 ± 0.7 versus 0.8 ± 0.4 ng/mL, P < 0.01). Linear regression analysis showed that overall, the plasma CatL levels were inversely correlated with the high-density lipoprotein levels (r = -0.32, P < 0.01) and positively with hs-CRP levels (r = 0.35, P < 0.01). Multiple logistic regression analyses shows that cathepsin L levels were independent predictors of CAD (add ratio, 1.8; 95% CI, 1.2 to 2.1; P < 0.01). These data demonstrated that increased levels of plasma CatL are closely associated with the presence of CAD and that circulating CatL serves as a useful biomarker for CAD.

Cell Senescence, Multiple Organelle Dysfunction and Atherosclerosis

Atherosclerosis is an age-related disorder associated with long-term exposure to cardiovascular risk factors. The asymptomatic progression of atherosclerotic plaques leads to major cardiovascular diseases (CVD), including acute myocardial infarctions or cerebral ischemic strokes in some cases. Senescence, a biological process associated with progressive structural and functional deterioration of cells, tissues and organs, is intricately linked to age-related diseases. Cell senescence involves coordinated modifications in cellular compartments and has been demonstrated to contribute to different stages of atheroma development. Senescence-based therapeutic strategies are currently being pursued to treat and prevent CVD in humans in the near-future. In addition, distinct experimental settings allowed researchers to unravel potential approaches to regulate anti-apoptotic pathways, facilitate excessive senescent cell clearance and eventually reverse atherogenesis to improve cardiovascular function. However, a deeper knowledge is required to fully understand cellular senescence, to clarify senescence and atherogenesis intertwining, allowing researchers to establish more effective treatments and to reduce the cardiovascular disorders' burden. Here, we present an objective review of the key senescence-related alterations of the major intracellular organelles and analyze the role of relevant cell types for senescence and atherogenesis. In this context, we provide an updated analysis of therapeutic approaches, including clinically relevant experiments using senolytic drugs to counteract atherosclerosis.

Emerging use of senolytics and senomorphics against aging and chronic diseases

Senescence is a state of cell cycle arrest that plays an important role in embryogenesis, wound healing and protection against cancer. Senescent cells also accumulate during aging and contribute to the development of age-related disorders and chronic diseases, such as atherosclerosis, type 2 diabetes, osteoarthritis, idiopathic pulmonary fibrosis, and liver disease. Molecules that induce apoptosis of senescent cells, such as dasatinib, quercetin, and fisetin, produce health benefits and extend lifespan in animal models. We describe here the mechanism of action of senolytics and senomorphics, many of which are derived from plants and fungi. We also discuss the possibility of using such compounds to delay aging and treat chronic diseases in humans.

RP105 plays a cardioprotective role in myocardial ischemia reperfusion injury by regulating the Toll‑like receptor 2/4 signaling pathways

The revascularization of blood vessels after myocardial infarction can lead to serious myocardial damage. Previous studies showed that radioprotective 105 kDa protein (RP105) is a specific negative regulator of myocardial ischemia reperfusion injury (MIRI). RP105 can modulate the Toll-like receptor (TLR)2/TLR4 signaling pathways. However, the synergistic effect of TLR2/4 regulated by RP105 during MIRI requires further investigation. To determine this effect, a MIRI model was established in rats in the present study. The expression of RP105 was depleted by transfecting RP105-siRNA and then detected using western blotting. Furthermore, the myocardium tissue was stained with the hematoxylin and eosin staining. Knockdown of RP105 promoted the activity of serum myocardial enzymes during MIRI and increased myocardial infarction. The present results indicated that knockdown of RP105 activated the TLR2/4 signaling pathway by modulating the myeloid differentiation primary response 88 and NF-κB signaling pathways. Furthermore, decreased expression of RP105 promoted myocardial cell apoptosis, which induced the damage of myocardial ischemic reperfusion. The present results suggested both TLR2 and TLR4 as key targets of RP105, thus RP105 may be a promising candidate to facilitate the development of novel therapeutic strategies for MIRI.

Exendin‑4 inhibits lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of TLR4/NF‑κB signaling pathway

The present study aimed to investigate the relationship between the protective effects of exendin‑4 (EX‑4) on lipotoxicity‑induced oxidative stress and meta‑inflammation in β‑cells and the toll‑like receptor 4 (TLR4)/NF‑κB signaling pathway. Lipotoxicity, hydrogen peroxide (H2O2)‑induced oxidative stress in β cells, obese Sprague Dawley rats and TLR4 truncation rats were utilized in the present study. The expression levels were detected by western blotting; cell apoptosis was detected by TUNEL assay; and the intracellular reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. The findings of the present study showed that EX‑4 inhibited the expression of TLR4, NF‑κB p65 subunit and p47phox in a concentration‑dependent manner, and decreased the intracellular level of ROS. Additionally, silencing of TLR4 expression enhanced the protective effects of EX‑4, while overexpression of TLR4 attenuated these protective influences. Simultaneously, it was demonstrated that TLR4 was involved in the process of EX‑4 intervention to inhibit H2O2‑induced oxidative stress in islet β‑cells. Moreover, it was found that EX‑4 also inhibited TLR4‑ or NF‑κB agonist‑induced oxidative stress. These results were also confirmed in an animal model of obese rats, in which EX‑4 was able to improve the function of β‑cells, attenuate oxidative stress, and inhibit the expression levels of TLR4 and NF‑κB p65 subunit in the pancreas of the diet‑induced obese rats. Furthermore, truncation of the TLR4 gene in SD rats delayed the aforementioned damage. In summary, EX‑4 may inhibit lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of the TLR4/NF‑κB signaling pathway.

Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of the metabolic syndrome (MetS) and comprises one of the largest health threats of the twenty-first century. In this chapter, we review the current state of knowledge of NAFLD and underline the striking similarities with atherosclerosis. We first describe current epidemiological data showing the staggering increase of NAFLD numbers and its related clinical and economic costs. We then provide an overview of pathophysiological hepatic processes in NAFLD and highlight the systemic aspects of NAFLD that point toward metabolic crosstalk between organs as an important cause of metabolic disease. Finally, we end by highlighting the currently investigated therapeutic approaches for NAFLD, which also show strong similarities with a range of treatment options for atherosclerosis.

Cathepsin S Deficiency Mitigated Chronic Stress-Related Neointimal Hyperplasia in Mice

Background Exposure to chronic psychosocial stress is a risk factor for atherosclerosis-based cardiovascular disease. We previously demonstrated the increased expressions of cathepsin S (CatS) in atherosclerotic lesions. Whether CatS participates directly in stress-related neointimal hyperplasia has been unknown. Methods and Results Male wild-type and CatS-deficient mice that underwent carotid ligation injury were subjected to chronic immobilization stress for morphological and biochemical studies at specific times. On day 14 after stress/surgery, stress enhanced the neointima formation. At the early time points, the stressed mice had increased plaque elastin disruption, cell proliferation, macrophage accumulation, mRNA and/or protein levels of vascular cell adhesion molecule-1, angiotensin II type 1 receptor, monocyte chemoattractant protein-1, gp91^phox, stromal cell-derived factor-1, C-X-C chemokine receptor-4, toll-like receptor-2, toll-like receptor-4, SC 35, galectin-3, and CatS as well as targeted intracellular proliferating-related molecules (mammalian target of rapamycin, phosphorylated protein kinase B, and p-glycogen synthase kinase-3α/β). Stress also increased the plaque matrix metalloproteinase-9 and matrix metalloproteinase-2 mRNA expressions and activities and aorta-derived smooth muscle cell migration and proliferation. The genetic or pharmacological inhibition of CatS by its specific inhibitor (Z- FL -COCHO) ameliorated the stressed arterial targeted molecular and morphological changes and stressed aorta-derived smooth muscle cell migration. Both the genetic and pharmacological interventions had no effect on increased blood pressure in stressed mice. Conclusions These results demonstrate an essential role of CatS in chronic stress-related neointimal hyperplasia in response to injury, possibly via the reduction of toll-like receptor-2/toll-like receptor-4-mediated inflammation, immune action, and smooth muscle cell proliferation, suggesting that CatS will be a novel therapeutic target for stress-related atherosclerosis-based cardiovascular disease.

Antiatherogenic effects of liraglutide in hyperglycemic apolipoprotein E-null mice via AMP-activated protein kinase-independent mechanisms

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert potent glucose-lowering effects without increasing risks for hypoglycemia and weight gain. Preclinical studies have demonstrated direct antiatherogenic effects of GLP-1RAs in normoglycemic animal models; however, the underlying mechanisms in hyperglycemic conditions have not been fully clarified. Here we aimed to elucidate the role of AMP-activated protein kinase (AMPK) in antiatherogenic effects of GLP-1RAs in hyperglycemic mice. Streptozotocin-induced hyperglycemic apolipoprotein E-null mice were treated with vehicle, low-dose liraglutide (17 nmol·kg^-1·day^-1), or high-dose liraglutide (107 nmol·kg^-1·day^-1) in experiment 1 and the AMPK inhibitor dorsomorphin, dorsomorphin + low-dose liraglutide, or dorsomorphin + high-dose liraglutide in experiment 2. Four weeks after treatment, aortas were collected to assess atherosclerosis. In experiment 1, metabolic parameters were similar among the groups. Assessment of atherosclerosis revealed that high-dose liraglutide treatments reduced lipid deposition on the aortic surface and plaque volume and intraplaque macrophage accumulation at the aortic sinus. In experiment 2, liraglutide-induced AMPK phosphorylation in the aorta was abolished by dorsomorphin; however, the antiatherogenic effects of high-dose liraglutide were preserved. In cultured human umbilical vein endothelial cells, liraglutide suppressed tumor necrosis factor-induced expression of proatherogenic molecules; these effects were maintained under small interfering RNA-mediated knockdown of AMPKα1 and in the presence of dorsomorphin. Conversely, in human monocytic U937 cells, the anti-inflammatory effects of liraglutide were abolished by dorsomorphin. In conclusion, liraglutide exerted AMPK-independent antiatherogenic effects in hyperlipidemic mice with streptozotocin-induced hyperglycemia, with the possible involvement of AMPK-independent suppression of proatherogenic molecules in vascular endothelial cells.

Computer-assisted prediction of atherosclerotic intimal thickness based on weight of adrenal gland, interleukin-6 concentration, and neural networks

Objective

Methods

Results

Conclusions

Preeclampsia-Associated Alteration of DNA Methylation in Fetal Endothelial Progenitor Cells

Objective

The pregnancy complication preeclampsia represents an independent risk factor for cardiovascular disease. Our previous research shows a diminished function of fetal endothelial colony-forming cells (ECFC), a proliferative subgroup of endothelial progenitor cells (EPC) in preeclampsia. The aim of this study was to further investigate whether DNA methylation of fetal EPC is affected in preeclampsia.

Methods

The genomic methylation pattern of fetal ECFC from uncomplicated and preeclamptic pregnancies was compared for 865918 CpG sites, and genes were classified into gene networks. Low and advanced cell culture passages were compared to explore whether expansion of fetal ECFC in cell culture leads to changes in global methylation status and if methylation characteristics in preeclampsia are maintained with increasing passage.

Results

A differential methylation pattern of fetal ECFC from preeclampsia compared to uncomplicated pregnancy was detected for a total of 1266 CpG sites in passage 3, and for 2362 sites in passage 5. Key features of primary networks implicated by methylation differences included cell metabolism, cell cycle and transcription and, more specifically, genes involved in cell-cell interaction and Wnt signaling. We identified an overlap between differentially regulated pathways in preeclampsia and cardiovascular system development and function. Cell culture passages 3 and 5 showed similar gene network profiles, and 1260 out of 1266 preeclampsia-associated methylation changes detected in passage 3 were confirmed in passage 5.

Conclusion

Methylation modification caused by preeclampsia is stable and detectable even in higher cell culture passages. An epigenetically modified endothelial precursor may influence both normal morphogenesis and postnatal vascular repair capacity. Further studies on epigenetic modifications in complicated pregnancies are needed to facilitate development of EPC based therapies for cardiovascular alterations.

Chronic Unpredictable Mild Stress Promotes Atherosclerosis via HMGB1/TLR4-Mediated Downregulation of PPARγ/LXRα/ABCA1 in ApoE-/- Mice

Background: Although our previous studies have confirmed that the activation of TLR4 is implicated in the development of atherosclerosis induced by chronic unpredicted mild stress (CUMS), the underling mechanism is largely unclear. Here, we hypothesized that CUMS accelerates atherosclerotic development through lowering PPARγ/LXRα-ABCA1 expression via HMGB1/TLR4 signaling. Methods: In present study, CUMS atherosclerotic animal models were established with AopE^-/- mice, and CUMS Raw 264.7 macrophage models were mimicked by high corticosterone treatment, These models were treated with Ethyl pyruvate (EP, an inhibitor of HMGB1), TLR4 inhibitor TAK-242, and PPARγ agonist RSG (Rosiglitazone) to test our hypothesis, respectively. Results: Our results indicated that the protein levels of HMGB1, TLR4, and pro-inflammatory cytokines including IL-1β, TNF-α were elevated with the development of atherosclerosis in CUMS mice, while the expressions of PPARγ, LXRα, and ABCA1 declined. Notably, HMGB1 inhibition by EP reversed CUMS-induced atherosclerotic development, pro-inflammatory cytokines upregulation, and PPARγ/LXRα-ABCA1 downregulation. The same trend was observed in the stressed mice treatment with TAK-242. Further experimental evidences indicated that EP, TAK-242, and RSG treatment notably corrected foam cell formation, HMGB1 release, and down-regulation of LXRα and ABCA1 in CUMS Raw 264.7 macrophage model. Conclusion: These results indicate that CUMS exacerbates atherosclerosis is likely via HMGB1-mediated downregulation of PPARγ/LXRα-ABCA1 through TLR4. These data reveal a novel mechanism by which CUMS aggravates atherosclerosis and may offer a potential therapeutic target for this disease.

Chronic stress: a critical risk factor for atherosclerosis

Chronic stress refers to the non-specific systemic reaction that occurs when the body is stimulated by various internal and external negative factors over a long time. The physiological response to chronic stress exposure has long been recognized as a potent modulator in the occurrence of atherosclerosis. Furthermore, research has confirmed the correlation between atherosclerosis and cardiovascular events. Chronic stress is pervasive during negative life events and may lead to the formation of plaque. Several epidemiological studies have shown that chronic stress is an independent risk factor for the development of vascular disease and for increased morbidity and mortality in patients with pre-existing coronary artery disease. One possible mechanism for this process is that chronic stress causes endothelial injury, directly activating macrophages, promoting foam cell formation and generating the formation of atherosclerotic plaque. This mechanism involves numerous variables, including inflammation, signal pathways, lipid metabolism and endothelial function. The mechanism of chronic stress in atherosclerosis should be further investigated to provide a theoretical basis for efforts to eliminate the effect of chronic stress on the cardiocerebral vascular system.

Chronic stress: a crucial promoter of cell apoptosis in atherosclerosis

Objective

Chronic stress may lead to augmented incidence rates of coronary and cerebrovascular diseases associated with atherosclerosis. However, few studies have focused on the effect of chronic stress on atherosclerosis plaque formation. Therefore, this study was designed to directly evaluate how chronic stress affects atherosclerosis.

Methods

Thirty rabbits were divided into three groups: the control group, balloon-injury operation + high-fat diet model group, and chronic stress + balloon-injury operation + high-fat diet model group. Physical and social stress were induced, and proteomic methods were applied to identify specific markers.

Results

After protein determination, the chronic stress + balloon-injury operation + high-fat diet model group exhibited significant upregulation of the following apoptosis-related proteins: UBE2K, caspase 3, caspase 9, BAX, P53, and FAS. In particular, real-time polymerase chain reaction showed that the protein expression of caspase 9 was significantly downregulated in the stress group compared with the non-stress groups. However, the other proteins showed significantly increased expression in the stress group.

Conclusion

Chronic stress may promote cell apoptosis in the physiopathologic process of atherosclerosis.

Exenatide Protects Against Cardiac Dysfunction by Attenuating Oxidative Stress in the Diabetic Mouse Heart

Cardiovascular disease is the major cause of death in patients with diabetes. Current treatment strategies for diabetes rely on lifestyle changes and glucose control to prevent angiopathy and organ failure. Exenatide, a glucagon-like peptide-1 (GLP-1) receptor agonist, is used as an add-on therapy to insulin treatment. Exenatide also has multiple beneficial effects in addition to its hypoglycemic effects, such as preventing hepatic steatosis and protecting against cardiac injury from doxorubicin-induced cardiotoxicity or ischemic reperfusion. However, the mechanisms underlying the cardioprotective effects of exenatide in diabetes have not been fully clarified. To address this issue, we investigated the cardioprotective effects of exenatide in type 1 and type 2 diabetic mice. We found that exenatide simultaneously attenuated reactive oxidative species (ROS) production through increases in the antioxidant enzymes manganese dependent superoxide dismutase (MnSOD) and catalase. Moreover, exenatide decreased tumor protein P53 (p53) expression and prevented cell apoptosis in H9c2 cells. The presence of the catalase inhibitor 3-AT attenuated the effects of exenatide. Overall, the results strongly indicate that exenatide treatment may be protective against the development of diabetic cardiomyopathy.

GLP-1 Receptor Agonist Exendin-4 Attenuates NR4A Orphan Nuclear Receptor NOR1 Expression in Vascular Smooth Muscle Cells

AIMS

Recently, incretin therapy has attracted increasing attention because of its potential use in tissue-protective therapy. Neuron-derived orphan receptor 1 (NOR1) is a nuclear orphan receptor that regulates vascular smooth muscle cell (VSMC) proliferation. In the present study, we investigated the vascular-protective effect of Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor agonist, by inhibiting NOR1 expression in VSMCs.

METHODS

We classified 7-week-old male 129X1/SvJ mice into control group and Ex-4 low- and high-dose-treated groups fed normal or high-fat diets, respectively. Endothelial denudation injuries were induced in the femoral artery at 8 weeks of age, followed by the evaluation of neointima formation at 12 weeks of age. To evaluate VSMC proliferation, bromodeoxyuridine incorporation assay and cell cycle distribution analysis were performed. NOR1 and cell cycle regulators were detected using immunohistochemistry, western blotting, quantitative reverse-transcription polymerase chain reaction, and luciferase assays.

RESULTS

Ex-4 treatment reduced vascular injury-induced neointima formation compared with controls. In terms of VSMCs occupying the neointima area, VSMC numbers and NOR1-expressing proliferative cells were significantly decreased by Ex-4 in a dose-dependent manner in both diabetic and non-diabetic mice. In vitro experiments using primary cultured VSMCs revealed that Ex-4 attenuated NOR1 expression by reducing extracellular signal-regulated kinase-mitogen-activated protein kinase and cAMP-responsive element-binding protein phosphorylations. Furthermore, in the cell cycle distribution analysis, serum-induced G1-S phase entry was significantly attenuated by Ex-4 treatment of VSMCs by inhibiting the induction of S-phase kinase-associated protein 2.

CONCLUSION

Ex-4 attenuates neointima formation after vascular injury and VSMC proliferation possibly by inhibiting NOR1 expression.