Proinflammation: the key to arterial aging

Proinflammation, profibrosis, and arterial aging

Aging is a major risk factor for quintessential cardiovascular diseases, which are closely related to arterial proinflammation. The age-related alterations of the amount, distribution, and properties of the collagen fibers, such as cross-links and degradation in the arterial wall, are the major sequelae of proinflammation. In the aging arterial wall, collagen types I, II, and III are predominant,  and are mainly produced by stiffened vascular smooth muscle cells (VSMCs) governed by proinflammatory signaling, leading to profibrosis. Profibrosis is regulated by an increase in the proinflammatory molecules angiotensin II, milk fat globule-EGF-VIII, and transforming growth factor-beta 1 (TGF-β1) signaling and a decrease in the vasorin signaling cascade. The release of these proinflammatory factors triggers the activation of matrix metalloproteinase type II (MMP-2) and activates profibrogenic TGF-β1 signaling, contributing to profibrosis. The age-associated increase in activated MMP-2 cleaves latent TGF-β and subsequently increases TGF-β1 activity leading to collagen deposition in the arterial wall. Furthermore, a blockade of the proinflammatory signaling pathway alleviates the fibrogenic signaling, reduces profibrosis, and prevents arterial stiffening with aging. Thus, age-associated proinflammatory-profibrosis coupling is the underlying molecular mechanism of arterial stiffening with advancing age.

Calorie Restriction Curbs Proinflammation That Accompanies Arterial Aging, Preserving a Youthful Phenotype

Background

Aging exponentially increases the incidence of morbidity and mortality of quintessential cardiovascular disease mainly due to arterial proinflammatory shifts at the molecular, cellular, and tissue levels within the arterial wall. Calorie restriction (CR) in rats improves arterial function and extends both health span and life span. How CR affects the proinflammatory landscape of molecular, cellular, and tissue phenotypic shifts within the arterial wall in rats, however, remains to be elucidated.

Methods and Results

Aortae were harvested from young (6‐month‐old) and old (24‐month‐old) Fischer 344 rats, fed ad libitum and a second group maintained on a 40% CR beginning at 1 month of age. Histopathologic and morphometric analysis of the arterial wall demonstrated that CR markedly reduced age‐associated intimal medial thickening, collagen deposition, and elastin fractionation/degradation within the arterial walls. Immunostaining/blotting showed that CR effectively prevented an age‐associated increase in the density of platelet‐derived growth factor, matrix metalloproteinase type II activity, and transforming growth factor beta 1 and its downstream signaling molecules, phospho‐mothers against decapentaplegic homolog‐2/3 (p‐SMAD‐2/3) in the arterial wall. In early passage cultured vascular smooth muscle cells isolated from AL and CR rat aortae, CR alleviated the age‐associated vascular smooth muscle cell phenotypic shifts, profibrogenic signaling, and migration/proliferation in response to platelet‐derived growth factor.

Conclusions

CR reduces matrix and cellular proinflammation associated with aging that occurs within the aortic wall and that are attributable to platelet‐derived growth factor signaling. Thus, CR reduces the platelet‐derived growth factor–associated signaling cascade, contributing to the postponement of biological aging and preservation of a more youthful aortic wall phenotype.

SKA-31, an activator of Ca2+-activated K+ channels, improves cardiovascular function in aging

Aging represents an independent risk factor for the development of cardiovascular disease, and is associated with complex structural and functional alterations in the vasculature, such as endothelial dysfunction. Small- and intermediate-conductance, Ca²⁺-activated K⁺ channels (KCa2.3 and KCa3.1, respectively) are prominently expressed in the vascular endothelium, and pharmacological activators of these channels induce robust vasodilation upon acute exposure in isolated arteries and intact animals. However, the effects of prolonged in vivo administration of such compounds are unknown. In our study, we hypothesized that such treatment would ameliorate aging-related cardiovascular deficits. Aged (∼18 months) male Sprague Dawley rats were treated daily with either vehicle or the KCa channel activator SKA-31 (10 mg/kg, intraperitoneal injection; n = 6/group) for 8 weeks, followed by echocardiography, arterial pressure myography, immune cell and plasma cytokine characterization, and tissue histology. Our results show that SKA-31 administration improved endothelium-dependent vasodilation, reduced agonist-induced vascular contractility, and prevented the aging-associated declines in cardiac ejection fraction, stroke volume and fractional shortening, and further improved the expression of endothelial KCa channels and associated cell signalling components to levels similar to those observed in young male rats (∼5 months at end of study). SKA-31 administration did not promote pro-inflammatory changes in either T cell populations or plasma cytokines/chemokines, and we observed no overt tissue histopathology in heart, kidney, aorta, brain, liver and spleen. SKA-31 treatment in young rats had little to no effect on vascular reactivity, select protein expression, tissue histology, plasma cytokines/chemokines or immune cell properties. Collectively, these data demonstrate that administration of the KCa channel activator SKA-31 improved aging-related cardiovascular function, without adversely affecting the immune system or promoting tissue toxicity.

[The functions of arterial sympathetic innervation: from development to pathology]

Arterial sympathetic innervation (ASI) is a complex biological process requiring a fine axonal guidance by arteries. Its physiological impact has remained unknown for decades but recently started to be better understood and recognized. ASI is a key element of the adaptive response of the cardiovascular system to challenging situations (exposure to cold, exercise…) as ASI controls the diameter of resistance arteries, thus blood supply to organs and systemic arterial blood pressure via arterial tone modulation. Defaults in ASI can lead to diseases, acting as a main cause or as an aggravating factor. Its impact is actively studied in cardiovascular diseases representing major public health issues, like hypertension, but ASI could also play a role in aging and many more pathological processes including cancer.

Rise and fall of elastic fibers from development to aging. Consequences on arterial structure-function and therapeutical perspectives

In the arteries of vertebrates, evolution has given rise to resilient macromolecular structures, elastin and elastic fibers, capable of sustaining an elevated blood pressure and smoothening the discontinuous blood flow and pressure generated by the heart. Elastic fibers are produced only during development and childhood, before being progressively degraded by mechanical stress and enzymatic activities during adulthood and aging. During this period, arterial elastic fiber calcification and loading of lipids also occur, all of these events conducting to arteriosclerosis. This leads to a progressive dysfunction of the large elastic arteries inducing elevated blood pressure as well as altered hemodynamics and organ perfusion, which induce more global malfunctions of the body during normal aging. Additionally, some arterial conditions occur more frequently with advancing age, such as atherosclerosis or aneurysms, which are called age-related diseases or pathological aging. The physiological or pathological degradation of elastic fibers and function of elastic arteries seemed to be rather inevitable over time. However, during the recent years, different molecules - including several ATP-dependent potassium channel openers, such as minoxidil - have been shown to re-induce elastin production and elastic fiber assembly, leading to improvements in the arterial structure and function or in organ perfusion. This review summarizes the changes in the arterial elastic fibers and structure from development until aging, and presents some of the potential pharmacotherapies leading to elastic fiber neosynthesis and arterial function improvement.

MFG-E8 mediates arterial aging by promoting the proinflammatory phenotype of vascular smooth muscle cells

BACKGROUND

Among older adults, arterial aging is the major factor contributing to increased risk for cardiovascular disease-related morbidity and mortality. The chronic vascular inflammation that accompanies aging causes diffuse intimal-medial thickening of the arterial wall, thus increasing the vulnerability of aged vessels to vascular insults. Milk fat globule-epidermal growth factor 8 (MFG-E8) is a biomarker for aging arteries. This integrin-binding glycoprotein, induced by angiotensin II, facilitates vascular smooth muscle cell (VSMC) proliferation and invasion in aging vasculatures. This study investigated whether MFG-E8 directly mediates the initial inflammatory responses in aged arteries or VSMCs.

METHODS

A model of neointimal hyperplasia was induced in the common carotid artery (CCA) of aged mice to exacerbate age-associated vascular remodeling. Recombinant MFG-E8 (rMFG-E8) was administered to the injured artery using Pluronic gel to accentuate the effect on age-related vascular pathophysiology. The MFG-E8 level, leukocyte infiltration, and proinflammatory cell adhesion molecule (CAM) expression in the arterial wall were evaluated through immunohistochemistry. By using immunofluorescence and immunoblotting, the activation of the critical proinflammatory transcription factor nuclear factor (NF)-κB in the injured CCAs was analyzed. Immunofluorescence, immunoblotting, and quantitative real-time polymerase chain reaction were conducted using VSMCs isolated from the aortas of young and aged mice to assess NF-κB nuclear translocation, NF-κB-dependent gene expression, and cell proliferation. The extent of intimal-medial thickening in the injured vessels was analyzed morphometrically. Finally, Transwell migration assay was used to examine VSMC migration.

RESULTS

Endogenous MFG-E8 expression in aged CCAs was significantly induced by ligation injury. Aged CCAs treated with rMFG-E8 exhibited increased leukocyte extravasation, CAM expression, and considerably increased NF-κB activation induced by rMFG-E8 in the ligated vessels. Exposure of early passage VSMCs from aged aortas to rMFG-E8 substantially increased NF-κB activation, proinflammatory gene expression, and cell proliferation. However, rMFG-E8 attenuated VSMC migration.

CONCLUSIONS

MFG-E8 promoted the proinflammatory phenotypic shift of aged VSMCs and arteries, rendering the vasculature prone to vascular diseases. MFG-E8 may constitute a novel therapeutic target for retarding the aging processes in such vessels.

Smooth muscle cell and arterial aging: basic and clinical aspects

Arterial aging engages a plethora of key signalling pathways that act in concert to induce vascular smooth muscle cell (VSMC) phenotypic changes leading to vascular degeneration and extracellular matrix degradation responsible for alterations of the mechanical properties of the vascular wall. This review highlights proof-of-concept examples of components of the extracellular matrix, VSMC receptors which connect extracellular and intracellular structures, and signalling pathways regulating changes in mechanotransduction and vascular homeostasis in aging. Furthermore, it provides a new framework for understanding how VSMC stiffness and adhesion to extracellular matrix contribute to arterial stiffness and how interactions with endothelial cells, platelets, and immune cells can regulate vascular aging. The identification of the key players of VSMC changes operating in large and small-sized arteries in response to increased mechanical load may be useful to better elucidate the causes and consequences of vascular aging and associated progression of hypertension, arteriosclerosis, and atherosclerosis.

Carbonic Anhydrase 1-Mediated Calcification Is Associated With Atherosclerosis, and Methazolamide Alleviates Its Pathogenesis

Vascular calcification is an important pathogenic process in atherosclerosis (AS); however, its immediate cause is unknown. Our previous study demonstrated that carbonic anhydrase 1 (CA1) stimulates ossification and calcification in ankylosing spondylitis and breast cancer. The current study investigated whether CA1 plays an important role in AS calcification and whether the CA inhibitor methazolamide (MTZ) has a therapeutic effect on AS. We successfully established an AS model by administration of a high-fat diet to apolipoprotein E (ApoE^−/−) mice. The treated animals had significantly increased serum levels of high-density lipoprotein cholesterol (HDL-c) and nitric oxide (NO) and decreased serum concentrations of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), interleukin (IL-6), interferon (IFN)-γ, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-α (TNF-α), chemokine (C-X-C motif) ligand 1/keratinocyte-derived chemokine (CXCL1/KC), and C-C motif chemokine ligand 2 (CCL2)/monocyte chemoattractant protein 1 (MCP-1). The treated mice also had reduced AS plaque areas and fat accumulation, with no clear calcium deposition in the intima of the blood vessels. CA1 expression was significantly increased in the aortic lesions, particularly in calcified regions, but the expression was dramatically lower in the mice that received MTZ treatment or MTZ preventive treatment. CA1 was also highly expressed in human AS tissues and in rat vascular smooth muscle cells (VSMCs) with β-glycerophosphate (㒐β-GP)-induced calcification. Acetazolamide (AZ), a CA inhibitor with a chemical structure similar to MTZ, markedly suppressed calcification and reduced CA1, IL-6, IFN-γ, GM-CSF, and TNF-α expression in cultured VSMCs. Anti-CA1 small interfering ribonucleic acid (siRNA) significantly suppressed calcification, cell proliferation, and migration, promoted apoptosis, and reduced IL-6, IFN-γ, GM-CSF, and TNF-α secretion in cultured VSMCs. These results demonstrated that CA1 expression and CA1-mediated calcification are significantly associated with AS progression. MTZ significantly alleviated AS and suppressed CA1 expression and proinflammatory cytokine secretion, indicating the potential use of this drug for AS treatment.

The role of elastin-derived peptides in human physiology and diseases

Once considered as inert, the extracellular matrix recently revealed to be biologically active. Elastin is one of the most important components of the extracellular matrix. Many vital organs including arteries, lungs and skin contain high amounts of elastin to assure their correct function. Physiologically, the organism contains a determined quantity of elastin from the early development which may remain physiologically constant due to its very long half-life and very low turnover. Taking into consideration the continuously ongoing challenges during life, there is a physiological degradation of elastin into elastin-derived peptides which is accentuated in several disease states such as obstructive pulmonary diseases, atherosclerosis and aortic aneurysm. These elastin-derived peptides have been shown to have various biological effects mediated through their interaction with their cognate receptor called elastin receptor complex eliciting several signal transduction pathways. In this review, we will describe the production and the biological effects of elastin-derived peptides in physiology and pathology.

The Hardest Part

Aging has a significant impact not only on every single individual but on society as a whole. Today, people throughout the world exhibit an extended lifespan. Therefore, it becomes increasingly important to develop novel concepts that encourage a modern understanding of the aging process. The concept of healthy aging shifts the perception of aging as a burden towards aging as an opportunity for an extended healthy phase in later life. Morbidity and mortality in the elderly population are greatly defined by a raise in the incidence and prevalence of cardiovascular diseases. Consequently, it is critical to identify risk factors and underlying mechanisms that render the aging (cardio)vascular system prone to disease. In this review, we focus on structural mechanisms of arterial stiffening as a major manifestation of vascular aging and its functional implications for the concept of healthy aging.

Endothelial PPARγ Is Crucial for Averting Age-Related Vascular Dysfunction by Stalling Oxidative Stress and ROCK

Aging plays a significant role in the progression of vascular diseases and vascular dysfunction. Activation of the ADP-ribosylation factor 6 and small GTPases by inflammatory signals may cause vascular permeability and endothelial leakage. Pro-inflammatory molecules have a significant effect on smooth muscle cells (SMC). The migration and proliferation of SMC can be promoted by tumor necrosis factor alpha (TNF-α). TNF-α can also increase oxidative stress in SMCs, which has been identified to persuade DNA damage resulting in apoptosis and cellular senescence. Peroxisome proliferator-activated receptor (PPAR) acts as a ligand-dependent transcription factor and a member of the nuclear receptor superfamily. They play key roles in a wide range of biological processes, including cell differentiation and proliferation, bone formation, cell metabolism, tissue remodeling, insulin sensitivity, and eicosanoid signaling. The PPARγ activation regulates inflammatory responses, which can exert protective effects in the vasculature. In addition, loss of function of PPARγ enhances cardiovascular events and atherosclerosis in the vascular endothelium. This appraisal, therefore, discusses the critical linkage of PPARγ in the inflammatory process and highlights a crucial defensive role for endothelial PPARγ in vascular dysfunction and disease, as well as therapy for vascular aging.

Astragaloside IV Suppresses High Glucose-Induced NLRP3 Inflammasome Activation by Inhibiting TLR4/NF-κB and CaSR

Long-term exposure to high glucose induces vascular endothelial inflammation that can result in cardiovascular disease. Astragaloside IV (As-IV) is widely used for anti-inflammatory treatment of cardiovascular diseases. However, its mechanism of action is still not fully understood. In this study, we investigated the effect of As-IV on high glucose-induced endothelial inflammation and explored its possible mechanisms. In vivo, As-IV (40 and 80 mg/kg/d) was orally administered to rats for 8 weeks after a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg). In vitro, human umbilical vein endothelial cells (HUVECs) were treated with high glucose (33 mM glucose) in the presence or absence of As-IV, NPS2143 (CaSR inhibitor), BAY 11-7082 (NF-κB p65 inhibitor), and INF39 (NLRP3 inhibitor), and overexpression of CaSR was induced by infection of CaSR-overexpressing lentiviral vectors to further discuss the anti-inflammatory property of As-IV. The results showed that high glucose increased the expression of interleukin-18 (IL-18), interleukin-1β (IL-1β), NLRP3, caspase-1, and ASC, as well as the protein level of TLR4, nucleus p65, and CaSR. As-IV can reverse these changes in vivo and in vitro. Meanwhile, NPS2143, BAY 11-7082, and INF39 could significantly abolish the high glucose-enhanced NLRP3, ASC, caspase-1, IL-18, and IL-1β expression in vitro. In addition, both NPS2143 and BAY 11-7082 attenuated high glucose-induced upregulation of NLRP3, ASC, caspase-1, IL-18, and IL-1β expression. In conclusion, this study suggested that As-IV could inhibit high glucose-induced NLRP3 inflammasome activation and subsequent secretion of proinflammatory cytokines via inhibiting TLR4/NF-κB signaling pathway and CaSR, which provides new insights into the anti-inflammatory activity of As-IV.

Chronic Kidney Disease and Pulse Wave Velocity: A Narrative Review

Chronic kidney disease (CKD) is associated with excess cardiovascular mortality, resulting from both traditional and nontraditional, CKD-specific, cardiovascular risk factors. Nontraditional risk factors include the entity Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) which is characterised by disorders of bone and mineral metabolism, including biochemical abnormalities of hyperphosphatemia and hyperparathyroidism, renal osteodystrophy, and vascular calcification. Increased arterial stiffness in the CKD population can be attributed amongst other influences to progression of vascular calcification, with significant resultant contribution to the cardiovascular disease burden. Pulse wave velocity (PWV) measured over the carotid-femoral arterial segments is the noninvasive gold-standard technique for measurement of aortic stiffness and has been suggested as a surrogate cardiovascular end-point. A PWV value of 10 m/s or greater has been recommended as a suitable cut-off for an increased risk of cardiovascular mortality. CKD is a risk factor for an excessive rate of increase in aortic stiffness, reflected by increases in PWV, and increased aortic PWV in CKD shows faster progression than for individuals with normal kidney function. Patients with varying stages of CKD, as well as those on dialysis or with a kidney transplant, have different biological milieu which influence aortic stiffness and associated changes in PWV. This review discusses the pathophysiology of arterial stiffness with CKD and outlines the literature on PWV across the spectrum of CKD, highlighting that determination of arterial stiffness using aortic PWV can be a useful diagnostic and prognostic tool for assessing cardiovascular disease in the CKD population.

Oxidation of methionine residues in human apolipoprotein A-I generates a potent pro-inflammatory molecule

Amyloid deposits of apolipoprotein A-I (apoA-I) and inflammation are common in atherosclerotic arteries. In this study, we investigated the interplay between oxidation of apoA-I methionine residues (Met(O)-ApoA-I), a known amyloidogenic modification of apoA-I, and the inflammatory response of immune cells. Soluble pre-fibrillar Met(O)-ApoA-I, but not apoA-I, induced intracellular accumulation of pro-interleukin (IL)-1β and secretion of the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and IL-6 in mouse bone marrow-derived macrophages (BMDMs) and human primary monocytes. Additionally, secretion of mature IL-1β was also activated in human monocytes. The pro-inflammatory activity of Met(O)-ApoA-I was Toll-like receptor 4 (TLR4)-dependent and CD36-independent and was solely determined by oxidation of apoA-I methionine residues, in particular Met-86 and Met-148. In contrast, amyloid fibrils or reconstituted high-density lipoproteins (HDLs) generated from Met(O)-ApoA-I did not induce cytokine production in BMDMs. Although lipid-free Met(O)-ApoA-I remained functional in extracting lipids from cells and generating HDL, it gained strong pro-inflammatory properties that may aggravate local inflammation in the arteries and atherosclerosis. Our study indicates that oxidation of apoA-I methionine residues produces a potent danger-associated molecular pattern capable of stimulating pro-inflammatory cytokine secretion at levels similar to those induced by known pathogen-associated molecular patterns, such as lipopolysaccharide.

Maoberry (Antidesma bunius) ameliorates oxidative stress and inflammation in cardiac tissues of rats fed a high-fat diet

Backgound

Chronic fat-rich diets consumption is increased risk associated with cardiovascular diseases (CVD). Prevention or reduction the progression of cardiac tissue deterioration could benefit in CVD. This study aimed to examine the effects of maoberry (Antidesma bunius), a antioxidant-rich tropical fruit, supplementation on oxidative stress and inflammation in cardiac tissues of rats fed a high-fat diet (HFD).

Methods

The male rats orally received HFD with maoberry extract doses of 0.38, 0.76 or 1.52 g/kg or simvastatin (10 mg/kg) for 12 weeks. At the end of the experimental period, the rats were fasted, euthanized and harvested for the hearts.

Results

Significantly reduced oxidative stress (malondialdehyde levels) and enhanced antioxidant capacity (ferric-reducing activities) in cardiac tissues of the rats were found. Maoberry extract remarkably ameliorated the expressions of genes involved with pro-inflammatory such as the tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1) and endothelial nitric oxide synthase (eNOS).

Conclusions

Our findings suggest that maoberry extract has remarkable effects on preventing progression of cardiac tissue deterioration at least through lowering oxidative stress and inflammation.

Primate stem cells: bridge the translation from basic research to clinic application

A growing body of literature has shown that stem cells are very effective for the treatment of degenerative diseases in rodents but these exciting results have not translated to clinical practice. The difference results from the divergence in genetic, metabolic, and physiological phenotypes between rodents and humans. The high degree of similarity between non-human primates (NHPs) and humans provides the most accurate models for preclinical studies of stem cell therapy. Using a NHP model to understand the following key issues, which cannot be addressed in humans or rodents, will be helpful for extending stem cell applications in the basic science and the clinic. These issues include pluripotency of primate stem cells, the safety and efficiency of stem cell therapy, and transplantation procedures of stem cells suitable for clinical translation. Here we review studies of the above issues in NHPs and current challenges of stem cell applications in both basic science and clinical therapies. We propose that the use of NHP models, in particular combining the serial production and transplantation procedures of stem cells is the most useful for preclinical studies designed to overcome these challenges.

Proinflammatory Arterial Stiffness Syndrome: A Signature of Large Arterial Aging

Age-associated structural and functional remodeling of the arterial wall produces a productive environment for the initiation and progression of hypertension and atherosclerosis. Chronic aging stress induces low-grade proinflammatory signaling and causes cellular proinflammation in arterial walls, which triggers the structural phenotypic shifts characterized by endothelial dysfunction, diffuse intimal-medial thickening, and arterial stiffening. Microscopically, aged arteries exhibit an increase in arterial cell senescence, proliferation, invasion, matrix deposition, elastin fragmentation, calcification, and amyloidosis. These characteristic cellular and matrix alterations not only develop with aging but can also be induced in young animals under experimental proinflammatory stimulation. Interestingly, these changes can also be attenuated in old animals by reducing low-grade inflammatory signaling. Thus, mitigating age-associated proinflammation and arterial phenotype shifts is a potential approach to retard arterial aging and prevent the epidemic of hypertension and atherosclerosis in the elderly.

Serum containing Buyang Huanwu decoction prevents age-associated migration and invasion of human vascular smooth muscle cells by up regulating SIRT1 expression

The migration and invasion of vascular smooth muscle cells (VSMCs) caused by advanced aging play an important role in diffuse intimal thickening, facilitate adverse arterial remodeling and contribute to the initiation and progression of cardiovascular diseases. The inhibitory function of Buyang Huanwu decoction (BYHWD) has been found on aortic intimal hyperplasia and VSMC proliferation, but its effect on age-associated migration and invasion remains unknown. Here, we used an in vitro angiotensin II (Ang II)-induced senescence model to study the effects of serum containing BYHWD (BYHWS) on the migratory and invasive capacities, matrix metalloprotease type 2 (MMP-2) expression and modulation of sirtuin1 (SIRT1) signaling in human aorta VSMCs (HA-VAMCs). Our results showed that BYHWS was able to inhibit Ang II-induced migration and invasion, with down-regulation of MMP-2. In addition, manipulation of SIRT1 by either over-expression or siRNA knockdown ameliorated or promoted cellular migration and invasion, respectively. Moreover, BYHWS reversed senescence-mediated decrease of SIRT1 levels and SIRT1 was required for BYHWS regulation on migration and invasion of senescent HA-VAMCs. In summary, our data demonstrated that BYHWS suppressed the migration and invasion of age-associated VSMC via an increase of the SIRT1 level, which provides novel insights for the therapy of age-associated cardiovascular diseases.

Longitudinal chemokine profile expression in a blood-brain barrier model from Alzheimer transgenic versus wild-type mice

BACKGROUND

Alzheimer's disease is widely described since the discovery of histopathological lesions in Mrs. Auguste Deter in 1906. However to date, there is no effective treatment to deal with the many cellular and molecular alterations. The complexity is even higher with the growing evidence of involvement of the peripheral blood mononuclear cells (PBMCs). Indeed, monocytes and T cells are shown in the cerebral parenchyma of AD patients, and these cells grafted to the periphery are able to go through the blood-brain barrier (BBB) in transgenic mouse models. It is known that BBB is disrupted at a late stage of AD. Chemokines represent major regulators of the transmigration of PBMCs, but many data were obtained on AD animal models. No data are available on the role of AD BBB in a healthy brain parenchyma. Therefore, the purpose of this study was to analyze the longitudinal chemokine profile expression in a BBB model from AD transgenic mice versus wild-type (WT) mice.

METHODS

A primary mouse BBB model was used with a luminal compartment either AD or WT and an abluminal compartment WT consisting of astrocytes and microglia. PBMCs were extracted by a ficoll gradient and incubated in the transwell with a direct contact with the luminal side, including the endothelial cells and pericytes. Then, the complete BBB model was incubated during 48 h, before supernatants and cell lysates were collected. Chemokines were quantified by X-MAP® luminex technology.

RESULTS

Abluminal CX3CL1 production increased in 12-month-old AD BBB while CX3CL1 levels decreased in luminal lysates. CCL3 in luminal compartment increased with aging and was significantly different compared to AD BBB at 12 months. In addition, abluminal CCL2 in 12-month-old AD BBB greatly decreased compared to levels in WT BBB. On the contrary, no modification was observed for CCL4, CCL5, and CXCL10.

CONCLUSION

These first findings highlighted the impact of AD luminal compartment on chemokine signature in a healthy brain parenchyma, suggesting new therapeutic or diagnostic approaches.

Saxagliptin Prevents Increased Coronary Vascular Stiffness in Aortic-Banded Mini Swine

Increased peripheral conduit artery stiffness has been shown in patients with heart failure (HF) with preserved ejection fraction. However, it is unknown whether this phenomenon extends to the coronary vasculature. HF with preserved ejection fraction may be driven, in part, by coronary inflammation, and inhibition of the enzyme DPP-4 (dipeptidyl-peptidase 4) reduces inflammation and oxidative stress. The purpose of this study was to determine the effect of saxagliptin-a DPP-4 inhibitor-on coronary stiffness in aortic-banded mini swine. We hypothesized saxagliptin would prevent increased coronary artery stiffness in a translational swine model with cardiac features of HF with preserved ejection fraction by inhibiting perivascular adipose tissue inflammation. Yucatan mini swine were divided into 3 groups: control, aortic-banded untreated HF, and aortic-banded saxagliptin-treated HF. Ex vivo mechanical testing was performed on the left circumflex and right coronary arteries, and advanced glycation end product, NF-κB (nuclear factor-κB), and nitrotyrosine levels were measured. An increase in the coronary elastic modulus of HF animals was associated with increased vascular advanced glycation end products, NF-κB, and nitrotyrosine levels compared with control and prevented by saxagliptin treatment. Aortas from healthy mice were treated with media from swine perivascular adipose tissue culture to assess its role on vascular stiffening. Conditioned media from HF and saxagliptin-treated HF animals increased mouse aortic stiffness; however, only perivascular adipose tissue from the HF group showed increased advanced glycation end products and NF-κB levels. In conclusion, our data show increased coronary conduit vascular stiffness was prevented by saxagliptin and associated with decreased advanced glycation end products, NF-κB, and nitrotyrosine levels in a swine model with potential relevance to HF with preserved ejection fraction.

Reduced vasorin enhances angiotensin II signaling within the aging arterial wall

The glycosylated protein vasorin physically interacts with the transforming growth factor-beta1 (TGF-β1) and functionally attenuates its fibrogenic signaling in the vascular smooth muscle cells (VSMCs) of the arterial wall. Angiotensin II (Ang II) amplifies TGF-β1 activation in the VSMCs of the arterial wall with aging. In this study, we hypothesized that a reduced expression of the protein vasorin plays a contributory role in magnifying Ang II-associated fibrogenic signaling in the VSMCs of the arterial wall with aging. The current study shows that vasorin mRNA and protein expression were significantly decreased both in aortic wall and VSMCs from old (30 mo) vs. young (8 mo) FXBN rats. Exposing young VSMCs to Ang II reduced vasorin protein expression to the levels of old untreated cells while treating old VSMCs with the Ang II type AT1 receptor antagonist Losartan upregulated vasorin protein expression up to the levels of young. The physical interaction between vasorin and TGF-β1 was significantly decreased in old vs. young VSMCs. Further, exposing young VSMCs to Ang II increased the levels of matrix metalloproteinase type II (MMP-2) activation and TGF-β1 downstream molecules p-SMAD-2/3 and collagen type I production up to the levels of old untreated VSMCs, and these effects were substantially inhibited by overexpressing vasorin. Administration of Ang II to young rats (8 mo) for 28 days via an osmotic minipump markedly reduced the expression of vasorin. Importantly, vasorin protein was effectively cleaved by activated MMP-2 both in vitro and in vivo. Administration of the MMP inhibitor, PD 166793, for 6 mo to young adult (18 mo) via a daily gavage markedly increased levels of vasorin in the aortic wall. Thus, reduced vasorin amplifies Ang II profibrotic signaling via an activation of MMP-2 in VSMCs within the aging arterial wall.

Cellular senescence links aging and diabetes in cardiovascular disease

Aging is a powerful independent risk factor for cardiovascular diseases such as atherosclerosis and heart failure. Concomitant diabetes mellitus strongly reinforces this effect of aging on cardiovascular disease. Cellular senescence is a fundamental mechanism of aging and appears to play a crucial role in the onset and prognosis of cardiovascular disease in the context of both aging and diabetes. Senescent cells are in a state of cell cycle arrest but remain metabolically active by secreting inflammatory factors. This senescence-associated secretory phenotype is a trigger of chronic inflammation, oxidative stress, and decreased nitric oxide bioavailability. A complex interplay between these three mechanisms results in age- and diabetes-associated cardiovascular damage. In this review, we summarize current knowledge on cellular senescence and its secretory phenotype, which might be the missing link between aging and diabetes contributing to cardiovascular disease.

Endothelial PPARγ (Peroxisome Proliferator-Activated Receptor-γ) Is Essential for Preventing Endothelial Dysfunction With Aging

Little is known about mechanisms that control vascular aging, particularly at the cell-specific level. PPARγ (peroxisome proliferator-activated receptor-γ) exerts protective effects in the vasculature when activated pharmacologically. To gain insight into the cell-specific impact of PPARγ, we examined the hypothesis that genetic interference with endothelial PPARγ would augment age-induced vascular dysfunction. We studied carotid arteries from adult (11.6±0.3 months) and old (24.7±0.6 months) mice with endothelial-specific expression of a human dominant negative mutation in PPARγ driven by the vascular cadherin promoter (E-V290M), along with age-matched, nontransgenic littermates. Acetylcholine (an endothelium-dependent agonist) produced similar relaxation in arteries from adult nontransgenic and E-V290M mice and old nontransgenic mice. In contrast, responses to acetylcholine were reduced by >50% in old male and female E-V290M mice (P<0.01). Endothelial function in old E-V290M mice was not altered by an inhibitor of COX (cyclooxygenase) but was restored to normal by a superoxide scavenger, an inhibitor of NADPH oxidase, or inhibition of ROCK (Rho kinase). Relaxation of arteries to nitroprusside, which acts directly on vascular muscle, was similar in all groups. Vascular expression of IL (interleukin)-6, Nox-2, and CDKN2A (a marker of senescence) was significantly increased in old E-V290M mice compared with controls (P<0.05). These findings provide the first evidence that age-related vascular dysfunction, inflammation, and senescence is accelerated after interference with endothelial PPARγ via mechanisms involving oxidative stress and ROCK. The finding of an essential protective role for endothelial PPARγ has implications for vascular disease and therapy for vascular aging.

Mitochondria-targeted antioxidant therapy with MitoQ ameliorates aortic stiffening in old mice

Aortic stiffening is a major independent risk factor for cardiovascular diseases, cognitive dysfunction, and other chronic disorders of aging. Mitochondria-derived reactive oxygen species are a key source of arterial oxidative stress, which may contribute to arterial stiffening by promoting adverse structural changes-including collagen overabundance and elastin degradation-and enhancing inflammation, but the potential for mitochondria-targeted therapeutic strategies to ameliorate aortic stiffening with primary aging is unknown. We assessed aortic stiffness [pulse-wave velocity (aPWV)], ex vivo aortic intrinsic mechanical properties [elastic modulus (EM) of collagen and elastin regions], and aortic protein expression in young (~6 mo) and old (~27 mo) male C57BL/6 mice consuming normal drinking water (YC and OC) or water containing mitochondria-targeted antioxidant MitoQ (250 µM; YMQ and OMQ) for 4 wk. Both baseline and postintervention aPWV values were higher in OC vs. YC (post: 482 ± 21 vs. 420 ± 5 cm/s, P < 0.05). MitoQ had no effect in young mice but decreased aPWV in old mice (OMQ, 426 ± 20, P < 0.05 vs. OC). MitoQ did not affect age-associated increases in aortic collagen-region EM, collagen expression, or proinflammatory cytokine expression, but partially attenuated age-associated decreases in elastin region EM and elastin expression. Our results demonstrate that MitoQ reverses in vivo aortic stiffness in old mice and suggest that mitochondria-targeted antioxidants may represent a novel, promising therapeutic strategy for decreasing aortic stiffness with primary aging and, possibly, age-related clinical disorders in humans. The destiffening effects of MitoQ treatment may be at least partially mediated by attenuation/reversal of age-related aortic elastin degradation. NEW & NOTEWORTHY We show that 4 wk of treatment with the mitochondria-specific antioxidant MitoQ in mice completely reverses the age-associated elevation in aortic stiffness, assessed as aortic pulse-wave velocity. The destiffening effects of MitoQ treatment may be at least partially mediated by attenuation of age-related aortic elastin degradation. Our results suggest that mitochondria-targeted therapeutic strategies may hold promise for decreasing arterial stiffening with aging in humans, possibly decreasing the risk of many chronic age-related clinical disorders.

The Role of Renin-Angiotensin-Aldosterone System and Its New Components in Arterial Stiffness and Vascular Aging

Many cardiovascular diseases present renin-angiotensin-aldosterone system (RAAS) hyperactivity as an important pathophysiological mechanism to be target in the therapeutic approaches. Moreover, arterial stiffness is currently considered as a new independent risk factor for cardiovascular disease in different clinical conditions, including hypertension and chronic kidney disease. In fact, excessive stimulation of angiotensin type 1 (AT1) receptors, as well as mineralocorticoid receptors, results in cellular growth, oxidative stress and vascular inflammation, which may lead to arterial stiffness and accelerate the process of vascular aging. In the last decades, a vasoprotective axis of the RAAS has been discovered, and now it is well established that new components with antioxidant and anti-inflammatory properties play important roles promoting vasodilation, natriuresis and reducing collagen deposition, thus attenuating arterial stiffness and improving endothelial function. In this review, we will focus on these pathophysiological mechanisms and the relevance of RAAS inhibition by different strategies to increase arterial compliance and to decelerate vascular aging.

High fat diet exacerbates Alzheimer's disease-related pathology in APPswe/PS1 mice

Alzheimer's disease (AD) is mainly characterized by the accumulation and aggregation of amyloid-β (Aβ) peptides in brain parenchyma and cerebral microvasculature. Unfortunately, the exact causes of the disease are still unclear. However, blood-brain barrier (BBB) dysfunction and activation of inflammatory pathways are implicated in AD pathogenesis. Importantly, advanced age and high fat diet, two major risk factors associated with AD, were shown to deeply affect BBB function and modulate the immune response. As such, this study evaluated the impact of age and high fat diet on AD progression. For this purpose, 3 (i.e. young) and 12 (i.e. aged) months old APPswe/PS1 mice were fed for 4 months with a high fat diet (i.e. Western diet (WD)) or normal diet. Interestingly, neurobehavioral tests revealed that WD accelerates age-associated cognitive decline without affecting parenchymal Aβ. Nonetheless, WD decreases matrix metalloproteinase-9 enzymatic activity and brain-derived neurotrophic factor mRNA and protein levels in brain, suggesting loss of synaptic plasticity. In the periphery, WD promotes systemic inflammation by increasing the levels of blood-circulating monocytes and monocyte chemotactic protein-1 production, which is accompanied by an augmentation of oxidized-low density lipoprotein levels in blood circulation. At the BBB, WD potentiates the age-induced increase of Aβ 1-40 accumulation and exacerbates the oxidative stress, specifically in cerebral microvasculature. These effects were accompanied by the dysfunction of pericytes, thus altering BBB functionality without compromising its integrity. Our study provides new insights into the implication of high fat diet in accelerating the cognitive decline in AD.

Alpha-1 antitrypsin deficiency: From the lung to the heart?

BACKGROUND AND AIMS

Alpha-1 antitrypsin (A1AT) is the most abundant serine protease inhibitor in human blood and exerts important anti-inflammatory and immune-modulatory effects. In combination with smoking or other long-term noxious exposures such as occupational dust and fumes, genetic A1AT deficiency can cause chronic obstructive pulmonary disease, a condition with elevated cardiovascular risk. The effects of A1AT deficiency on cardiovascular risk have hardly been studied today.

METHODS

Using data from 2614 adults from the population-based SAPALDIA cohort, we tested associations of serum A1AT and SERPINA1 mutations with carotid intima-media thickness (CIMT, measured by B-mode ultrasonography) or self-reported arterial hypertension or cardiovascular disease in multiple regression models using a Mendelian Randomization like analysis design. Mutations Pi-S and Pi-Z were coded as ordinal genotype score (MM, MS, MZ/SS, SZ and ZZ), according to their progressive biological impact.

RESULTS

Serum A1AT concentration presented a u-shaped association with CIMT. At the lower end of the A1AT distribution, an analogous, linear association between SERPINA1 score and higher CIMT was observed, resulting in an estimated 1.2% (95%-confidence interval -0.1-2.5) increase in CIMT per unit (p = 0.060). Genotype score was significantly associated with arterial hypertension with an odds ratio (OR) of 1.2 (1.0-1.5) per unit (p = 0.028). The association with cardiovascular disease was not significant (OR 1.3 (0.9-1.9)).

CONCLUSIONS

Our results support a possible causal relationship between genetic A1AT deficiency and increased cardiovascular risk, which needs to be better taken into account for the management of affected patients and first-degree relatives.

In Development-A New Paradigm for Understanding Vascular Disease

Under physiological conditions, the arterial endothelium exerts a powerful protective influence to maintain vascular homeostasis. However, during the development of vascular disease, these protective activities are lost, and dysfunctional endothelial cells actually promote disease pathogenesis. Numerous investigations have analyzed the characteristics of dysfunctional endothelium with a view to understanding the processes responsible for the dysfunction and to determining their role in vascular pathology. This review adopts an alternate approach: reviewing the mechanisms that contribute to the initial formation of a healthy protective endothelium and on how those mechanisms may be disrupted, precipitating the appearance of dysfunctional endothelial cells and the progression of vascular disease. This approach, which highlights the role of endothelial adherens junctions and vascular endothelial-cadherin in endothelial maturation and endothelial dysfunction, provides new insight into the remarkable biology of this important cell layer and its role in vascular protection and vascular disease.

Effects of Apelin on Cardiovascular Aging

Apelin is the endogenous ligand of APJ, the orphan G protein-coupled receptor. The apelin-APJ signal transduction pathway is widely expressed in the cardiovascular system and is an important factor in cardiovascular homeostasis. This signal transduction pathway has long been related to diseases with high morbidity in the elderly, such as atherosclerosis, coronary atherosclerotic heart disease, hypertension, calcific aortic valve disease, heart failure and atrial fibrillation. In this review, we discuss the apelin-APJ signal transduction pathway related to age-associated cardiovascular diseases.

Association between monocyte chemoattractant protein-1 and blood pressure in smokers

Objective

The expression level of monocyte chemoattractant protein-1 (MCP-1) is increased in atherosclerotic regions, inducing monocyte migration to the blood vessel wall. Although the serum MCP-1 concentration is higher in patients with than without cardiovascular disease, the precise correlations between the serum MCP-1 concentration and factors associated with smoking and atherosclerosis are unknown.

Methods

The serum MCP-1 concentration was measured using an enzyme-linked immunosorbent assay in 207 consecutive smokers who visited our smoking cessation clinic.

Results

Sex-adjusted analysis of smokers revealed that the MCP-1 concentration was positively correlated with age (β = 0.311), smoking duration (β = 0.342), systolic blood pressure (β = 0.225), and diastolic blood pressure (β = 0.137) but not with the body mass index. Multivariate regression analysis showed that smoking duration and systolic blood pressure were independent determinants of the MCP-1 concentration.

Conclusions

The MCP-1 concentration was positively correlated with blood pressure among smokers. Long-term smokers with high blood pressure may be more susceptible to plaque rupture at atherosclerotic lesion sites.

Effects of age and exercise training on coronary microvascular smooth muscle phenotype and function

Coronary microvascular function and blood flow responses during acute exercise are impaired in the aged heart but can be restored by exercise training. Coronary microvascular resistance is directly dependent on vascular smooth muscle function in coronary resistance arterioles; therefore, we hypothesized that age impairs contractile function and alters the phenotype of vascular smooth muscle in coronary arterioles. We further hypothesized that exercise training restores contractile function and reverses age-induced phenotypic alterations of arteriolar smooth muscle. Young and old Fischer 344 rats underwent 10 wk of treadmill exercise training or remained sedentary. At the end of training or cage confinement, contractile responses, vascular smooth muscle proliferation, and expression of contractile proteins were assessed in isolated coronary arterioles. Both receptor- and non-receptor-mediated contractile function were impaired in coronary arterioles from aged rats. Vascular smooth muscle shifted from a differentiated, contractile phenotype to a secretory phenotype with associated proliferation of smooth muscle in the arteriolar wall. Expression of smooth muscle myosin heavy chain 1 (SM1) was decreased in arterioles from aged rats, whereas expression of phospho-histone H3 and of the synthetic protein ribosomal protein S6 (rpS6) were increased. Exercise training improved contractile responses, reduced smooth muscle proliferation and expression of rpS6, and increased expression of SM1 in arterioles from old rats. Thus age-induced contractile dysfunction of coronary arterioles and emergence of a secretory smooth muscle phenotype may contribute to impaired coronary blood flow responses, but arteriolar contractile responsiveness and a younger smooth muscle phenotype can be restored with late-life exercise training. NEW & NOTEWORTHY Aging impairs contractile function of coronary arterioles and induces a shift of the vascular smooth muscle toward a proliferative, noncontractile phenotype. Late-life exercise training reverses contractile dysfunction of coronary arterioles and restores a young phenotype to the vascular smooth muscle.

Is Vascular Amyloidosis Intertwined with Arterial Aging, Hypertension and Atherosclerosis?

Vascular amyloidosis (VA) is a component of aging, but both VA and aging move forward together. Although, not all age-related molecules are involved with VA, some molecules are involved in a crosstalk between both of them. However, the cellular mechanism by which, vascular cells are phenotypically shifted to arterial remodeling, is not only involved in aging but also linked to VA. Additionally, patients with hypertension and atherosclerosis are susceptible to VA, while amyloidosis alone may provide fertile soil for the initiation and progression of subsequent hypertension and atherosclerosis. It is known that hypertension, atherosclerosis and amyloidosis can be viewed as accelerated aging. This review summarizes the available experimental and clinical evidence to help the reader to understand the advance and underlying mechanisms for VA involvement in and interaction with aging. Taken together, it is clear that VA, hypertension and atherosclerosis are closely intertwined with arterial aging as equal partners.

Nutrition and other lifestyle influences on arterial aging

As our world's population ages, cardiovascular diseases (CVD) will become an increasingly urgent public health problem. A key antecedent to clinical CVD and many other chronic disorders of aging is age-related arterial dysfunction, characterized by increased arterial stiffness and impaired arterial endothelial function. Accumulating evidence demonstrates that diet and nutrition may favorably modulate these arterial functions with aging, but many important questions remain. In this review, we will summarize the available information on dietary patterns and nutritional factors that have been studied for their potential to reduce arterial stiffness and improve endothelial function with age, with an emphasis on: 1) underlying physiological mechanisms, and 2) emerging areas of research on nutrition and arterial aging that may hold promise for preventing age-related CVD.

Inflammatory Markers for Arterial Stiffness in Cardiovascular Diseases

Arterial stiffness predicts an increased risk of cardiovascular events. Inflammation plays a major role in large arteries stiffening, related to atherosclerosis, arteriosclerosis, endothelial dysfunction, smooth muscle cell migration, vascular calcification, increased activity of metalloproteinases, extracellular matrix degradation, oxidative stress, elastolysis, and degradation of collagen. The present paper reviews main mechanisms explaining the crosstalk between inflammation and arterial stiffness and the most common inflammatory markers associated with increased arterial stiffness, considering the most recent clinical and experimental studies. Diverse studies revealed significant correlations between the severity of arterial stiffness and inflammatory markers, such as white blood cell count, neutrophil/lymphocyte ratio, adhesion molecules, fibrinogen, C-reactive protein, cytokines, microRNAs, and cyclooxygenase-2, in patients with a broad variety of diseases, such as metabolic syndrome, diabetes, coronary heart disease, peripheral arterial disease, malignant and rheumatic disorders, polycystic kidney disease, renal transplant, familial Mediterranean fever, and oral infections, and in women with preeclampsia or after menopause. There is strong evidence that inflammation plays an important and, at least, partly reversible role in the development of arterial stiffness, and inflammatory markers may be useful additional tools in the assessment of the cardiovascular risk in clinical practice. Combined assessment of arterial stiffness and inflammatory markers may improve non-invasive assessment of cardiovascular risk, enabling selection of high-risk patients for prophylactic treatment or more regular medical examination. Development of future destiffening therapies may target pro-inflammatory mechanisms.

Vascular aging: Molecular mechanisms and potential treatments for vascular rejuvenation

Aging is the main risk factor contributing to vascular dysfunction and the progression of vascular diseases. In this review, we discuss the causes and mechanisms of vascular aging at the tissue and cellular level. We focus on Endothelial Cell (EC) and Smooth Muscle Cell (SMC) aging due to their critical role in mediating the defective vascular phenotype. We elaborate on two categories that contribute to cellular dysfunction: cell extrinsic and intrinsic factors. Extrinsic factors reflect systemic or environmental changes which alter EC and SMC homeostasis compromising vascular function. Intrinsic factors induce EC and SMC transformation resulting in cellular senescence. Replenishing or rejuvenating the aged/dysfunctional vascular cells is critical to the effective repair of the vasculature. As such, this review also elaborates on recent findings which indicate that stem cell and gene therapies may restore the impaired vascular cell function, reverse vascular aging, and prolong lifespan.

Recent Progress in Vascular Aging: Mechanisms and Its Role in Age-related Diseases

As with many age-related diseases including vascular dysfunction, age is considered an independent and crucial risk factor. Complicated alterations of structure and function in the vasculature are linked with aging hence, understanding the underlying mechanisms of age-induced vascular pathophysiological changes holds possibilities for developing clinical diagnostic methods and new therapeutic strategies. Here, we discuss the underlying molecular mediators that could be involved in vascular aging, e.g., the renin-angiotensin system and pro-inflammatory factors, metalloproteinases, calpain-1, monocyte chemoattractant protein-1 (MCP-1) and TGFβ-1 as well as the potential roles of testosterone and estrogen. We then relate all of these to clinical manifestations such as vascular dementia and stroke in addition to reviewing the existing clinical measurements and potential interventions for age-related vascular dysfunction.

Impaired activity of adherens junctions contributes to endothelial dilator dysfunction in ageing rat arteries

KEY POINTS

Ageing-induced endothelial dysfunction contributes to organ dysfunction and progression of cardiovascular disease. VE-cadherin clustering at adherens junctions promotes protective endothelial functions, including endothelium-dependent dilatation. Ageing increased internalization and degradation of VE-cadherin, resulting in impaired activity of adherens junctions. Inhibition of VE-cadherin clustering at adherens junctions (function-blocking antibody; FBA) reduced endothelial dilatation in young arteries but did not affect the already impaired dilatation in old arteries. After junctional disruption with the FBA, dilatation was similar in young and old arteries. Src tyrosine kinase activity and tyrosine phosphorylation of VE-cadherin were increased in old arteries. Src inhibition increased VE-cadherin at adherens junctions and increased endothelial dilatation in old, but not young, arteries. Src inhibition did not increase dilatation in old arteries treated with the VE-cadherin FBA. Ageing impairs the activity of adherens junctions, which contributes to endothelial dilator dysfunction. Restoring the activity of adherens junctions could be of therapeutic benefit in vascular ageing.

ABSTRACT

Endothelial dilator dysfunction contributes to pathological vascular ageing. Experiments assessed whether altered activity of endothelial adherens junctions (AJs) might contribute to this dysfunction. Aortas and tail arteries were isolated from young (3-4 months) and old (22-24 months) F344 rats. VE-cadherin immunofluorescent staining at endothelial AJs and AJ width were reduced in old compared to young arteries. A 140 kDa VE-cadherin species was present on the cell surface and in TTX-insoluble fractions, consistent with junctional localization. Levels of the 140 kDa VE-cadherin were decreased, whereas levels of a TTX-soluble 115 kDa VE-cadherin species were increased in old compared to young arteries. Acetylcholine caused endothelium-dependent dilatation that was decreased in old compared to young arteries. Disruption of VE-cadherin clustering at AJs (function-blocking antibody, FBA) inhibited dilatation to acetylcholine in young, but not old, arteries. After the FBA, there was no longer any difference in dilatation between old and young arteries. Src activity and tyrosine phosphorylation of VE-cadherin were increased in old compared to young arteries. In old arteries, Src inhibition (saracatinib) increased: (i) 140 kDa VE-cadherin in the TTX-insoluble fraction, (ii) VE-cadherin intensity at AJs, (iii) AJ width, and (iv) acetylcholine dilatation. In old arteries treated with the FBA, saracatinib no longer increased acetylcholine dilatation. Saracatinib did not affect dilatation in young arteries. Therefore, ageing impairs AJ activity, which appears to reflect Src-induced phosphorylation, internalization and degradation of VE-cadherin. Moreover, impaired AJ activity can account for the endothelial dilator dysfunction in old arteries. Restoring endothelial AJ activity may be a novel therapeutic approach to vascular ageing.

Toll-like receptor-4 signaling pathway in aorta aging and diseases: "its double nature"

Recent advances in the field of innate immunity have revealed a complex role of innate immune signaling pathways in both tissue homeostasis and disease. Among them, the Toll-like receptor 4 (TLR-4) pathways has been linked to various pathophysiological conditions, such as cardiovascular diseases (CVDs). This has been interrogated by developing multiple laboratory tools that have shown in animal models and clinical conditions, the involvement of the TLR-4 signaling pathway in the pathophysiology of different CVDs, such as atherosclerosis, ischemic heart disease, heart failure, ischemia-reperfusion injury and aorta aneurysm. Among these, aorta aneurysm, a very complex pathological condition with uncertain etiology and fatal complications (i.e. dissection and rupture), has been associated with the occurrence of high risk cardiovascular conditions, including thrombosis and embolism. In this review, we discuss the possible role of TLR-4 signaling pathway in the development of aorta aneurysm, considering the emerging evidence from ongoing investigations. Our message is that emphasizing the role of TLR-4 signaling pathway in aorta aneurysm may serve as a starting point for future studies, leading to a better understanding of the pathophysiological basis and perhaps the effective treatment of this difficult human disease.

Immunological aspects of age-related diseases

The proportion of elderly people rises in the developed countries. The increased susceptibility of the elderly to infectious diseases is caused by immune dysfunction, especially T cell functional decline. Age-related hematopoietic stem cells deviate from lymphoid lineage to myeloid lineage. Thymus shrinks early in life, which is followed by the decline of naïve T cells. T-cell receptor repertoire diversity declines by aging, which is caused by cytomegalovirus-driven T cell clonal expansion. Functional decline of B cell induces antibody affinity declines by aging. Many effector functions including phagocytosis of myeloid cells are down regulated by aging. The studies of aging of myeloid cells have some controversial results. Although M1 macrophages have been shown to be replaced by anti-inflammatory (M2) macrophages by advanced age, many human studies showed that pro-inflammatory cytokines are elevated in older human. To solve this discrepancy here we divide age-related pathological changes into two categories. One is an aging of immune cell itself. Second is involvement of immune cells to age-related pathological changes. Cellular senescence and damaged cells in aged tissue recruit pro-inflammatory M1 macrophages, which produce pro-inflammatory cytokines and proceed to age-related diseases. Underlying biochemical and metabolic studies will open nutritional treatment.

Aging and the immune response to organ transplantation

An increasing number of older people receive organ transplants for various end-stage conditions. Although organ transplantation is an effective therapy for older patients (i.e., older than 65 years of age), such as in end-stage renal disease, this therapy has not been optimized for older patients because of our lack of understanding of the effect of aging and the immune response to organ transplantation. Here, we provide an overview of the impact of aging on both the allograft and the recipient and its effect on the immune response to organ transplantation. We describe what has been determined to date, discuss existing gaps in our knowledge, and make suggestions on necessary future studies to optimize organ transplantation for older people.

MiRNA Deregulation in Cardiac Aging and Associated Disorders

The prevalence of age-related diseases is increasing dramatically, among which cardiac disease represents the leading cause of death. Aging of the heart is characterized by various molecular and cellular hallmarks impairing both cardiomyocytes and noncardiomyocytes, and resulting in functional deteriorations of the cardiac system. The aging process includes desensitization of β-adrenergic receptor (βAR)-signaling and decreased calcium handling, altered growth signaling and cardiac hypertrophy, mitochondrial dysfunction and impaired autophagy, increased programmed cell death, low-grade inflammation of noncanonical inflammatory cells, and increased ECM deposition. MiRNAs play a fundamental role in regulating the processes underlying these detrimental changes in the cardiac system, indicating that MiRNAs are crucially involved in aging. Among others, MiR-34, MiR-146a, and members of the MiR-17-92 cluster, are deregulated during senescence and drive cardiac aging processes. It is therefore suggested that MiRNAs form possible therapeutic targets to stabilize the aged failing myocardium.

NANOG Restores Contractility of Mesenchymal Stem Cell-Based Senescent Microtissues

Mesenchymal stem cells (MSCs) have been extensively used in the field of tissue engineering as a source of smooth muscle cells (SMCs). However, recent studies showed deficits in the contractile function of SMCs derived from senescent MSCs and there are no available strategies to restore the contractile function that is impaired due to cellular or organismal senescence. In this study, we developed a tetracycline-regulatable system and employed micropost tissue arrays to evaluate the effects of the embryonic transcription factor, NANOG, on the contractility of senescent MSCs. Using this system, we show that expression of NANOG fortified the actin cytoskeleton and restored contractile function that was impaired in senescent MSCs. NANOG increased the expression of smooth muscle α-actin (ACTA2) as well as the contractile force generated by cells in three-dimensional microtissues. Interestingly, NANOG worked together with transforming growth factor-beta1 to further enhance the contractility of senescent microtissues. The effect of NANOG on contractile function was sustained for about 10 days after termination of its expression. Our results show that NANOG could reverse the effects of stem cell senescence and restore the myogenic differentiation potential of senescent MSCs. These findings may enable development of novel strategies to restore the function of senescent cardiovascular and other SMC-containing tissues.

The Pressure of Aging

Significant hemodynamic changes ensue with aging, leading to an ever-growing epidemic of hypertension. Alterations in central arterial properties play a major role in these hemodynamic changes. These alterations are characterized by an initial decline in aortic distensibility and an increase of diastolic blood pressure, followed by a sharp increase in pulse wave velocity (PWV), and an increase in pulse pressure (PP) beyond the sixth decade. However, the trajectories of PWV and PP diverge with advancing age. There is an increased prevalence of salt-sensitive hypertension with advancing age that is, in part, mediated by marinobufagenin, an endogenous sodium pump ligand.

Telomerase Therapy to Reverse Cardiovascular Senescence

Cellular senescence of endothelial cells plays an important role in the development of vascular lesions that ultimately lead to an atherosclerotic plaque. This review focuses on the age-related changes of endothelial and vascular smooth muscle cells that contribute to vascular disease and discusses potential new targets that could rejuvenate the vascular system and thereby prevent or delay atherosclerosis.

Advantages of nonhuman primates as preclinical models for evaluating stem cell-based therapies for Parkinson's disease

The derivation of dopaminergic neurons from induced pluripotent stem cells brings new hope for a patient-specific, stem cell-based replacement therapy to treat Parkinson's disease (PD) and related neurodegenerative diseases; and this novel cell-based approach has already proven effective in animal models. However, there are several aspects of this procedure that have yet to be optimized to the extent required for translation to an optimal cell-based transplantation protocol in humans. These challenges include pinpointing the optimal graft location, appropriately scaling up the graft volume, and minimizing the risk of chronic immune rejection, among others. To advance this procedure to the clinic, it is imperative that a model that accurately and fully recapitulates characteristics most pertinent to a cell-based transplantation to the human brain is used to optimize key technical aspects of the procedure. Nonhuman primates mimic humans in multiple ways including similarities in genomics, neuroanatomy, neurophysiology, immunogenetics, and age-related changes in immune function. These characteristics are critical to the establishment of a relevant model in which to conduct preclinical studies to optimize the efficacy and safety of cell-based therapeutic approaches to the treatment of PD. Here we review previous studies in rodent models, and emphasize additional advantages afforded by nonhuman primate models in general, and the baboon model in particular, for preclinical optimization of cell-based therapeutic approaches to the treatment of PD and other neurodegenerative diseases. We outline current unresolved challenges to the successful application of stem cell therapies in humans and propose that the baboon model in particular affords a number of traits that render it most useful for preclinical studies designed to overcome these challenges.