Human Internal Thoracic Artery Research Articles

Differential Suppressive Effects of Rho Kinase Inhibitor Fasudil on Serotonin- and Noradrenaline-Induced Contractions of Human Internal Thoracic Arteries and Saphenous Veins.

Rho kinase inhibitor fasudil exerts therapeutic effects against vasospasms. In this study, we aimed to compare its suppressive effects on serotonin (5-HT)- and noradrenaline (NAd)-induced contractions of human endothelium-denuded internal thoracic arteries (ITAs) and saphenous veins (SVs). NAd and 5-HT induced concentration-dependent contractions in both ITAs and SVs. However, fasudil (3 µmol/L) pretreatment decreased these constrictor-induced contractions in both ITAs and SVs. Fasudil exerted similar inhibitory effects on 5-HT and NAd in ITAs. However, in SVs, fasudil exerted stronger inhibitory effects on NAd-induced contractions than on 5-HT-induced contractions. Therefore, inhibitory effects of fasudil on 5-HT-induced contractions were stronger in ITAs than in SVs. Overall, these results suggest that Rho kinases exert different effects on the two vasoconstrictors in SVs, but not in ITAs, thus explaining their different graft patencies.

Calciprotein Particles Induce Cellular Compartment-Specific Proteome Alterations in Human Arterial Endothelial Cells.

Calciprotein particles (CPPs) are indispensable scavengers of excessive Ca2+ and PO43- ions in blood, being internalised and recycled by liver and spleen macrophages, monocytes, and endothelial cells (ECs). Here, we performed a pathway enrichment analysis of cellular compartment-specific proteomes in primary human coronary artery ECs (HCAEC) and human internal thoracic artery ECs (HITAEC) treated with primary (amorphous) or secondary (crystalline) CPPs (CPP-P and CPPs, respectively). Exposure to CPP-P and CPP-S induced notable upregulation of: (1) cytokine- and chemokine-mediated signaling, Ca2+-dependent events, and apoptosis in cytosolic and nuclear proteomes; (2) H+ and Ca2+ transmembrane transport, generation of reactive oxygen species, mitochondrial outer membrane permeabilisation, and intrinsic apoptosis in the mitochondrial proteome; (3) oxidative, calcium, and endoplasmic reticulum (ER) stress, unfolded protein binding, and apoptosis in the ER proteome. In contrast, transcription, post-transcriptional regulation, translation, cell cycle, and cell-cell adhesion pathways were underrepresented in cytosol and nuclear compartments, whilst biosynthesis of amino acids, mitochondrial translation, fatty acid oxidation, pyruvate dehydrogenase activity, and energy generation were downregulated in the mitochondrial proteome of CPP-treated ECs. Differentially expressed organelle-specific pathways were coherent in HCAEC and HITAEC and between ECs treated with CPP-P or CPP-S. Proteomic analysis of mitochondrial and nuclear lysates from CPP-treated ECs confirmed bioinformatic filtration findings.

Oxidative stress in the endothelial cell culture exposed to mitomycin C

Background. Atherosclerosis is one of the leading cardiovascular pathologies. Evidence suggests that DNA damage caused by endothelial cell exposure to mitomycin C (MMC) leads to endothelial dysfunction and is the risk factor for this disease. MMC is an alkylating mutagen involved in the development of oxidative stress, which is also a risk factor for atherosclerosis. Aim. To access the levels of oxidative stress markers in the primary human endothelial cell culture exposed to alkylating mutagen MMC.Material and Methods. Commercially available primary cultures of endothelial cells obtained from human coronary artery (HCAEC) and human internal thoracic artery (HITAEC) were used in the study. The cells were cultivated in the presence of 500 ng/mL MMC (experimental group) and without mutagenic load (control group). The levels of reactive oxygen species, reactive nitrogen species, and 8-OH-deoxyguanosine (8-OHdG) in cell growth media were assessed by enzyme-linked immunosorbent assay. The relative telomere length and expression of TERT and POT1 genes were accessed in endothelial cells by quantitative polymerase chain reaction. Statistical analysis of data was performed using GraphPad Prism 9 software.Results. There were no differences in the concentrations of reactive oxygen species, reactive nitrogen species (NO2 -, NO3 -, NO2 -/NO3 -), and 8-OHdG in HCAEC and HITAEC cultures exposed to MMC compared to the corresponding parameters in the non-exposed controls. At the same time, HCAEC and HITAEC exposed to MMC were characterized by a decrease in the relative telomere length compared to control (10.97 vs. 27.03 in HCAEC, p = 0.002 and 9.12 vs. 25.64 in HITAEC, p = 0.001). Moreover, we discovered 1.75-fold increase in the expression of POT1 gene in the experimental HCAEC compared to control (p = 0.019). No expression of TERT gene was observed in study groups.Conclusions. Alkylating mutagen MMC did not induce any pronounced oxidative stress in the primary human endothelial cells in vitro. The development of endothelial dysfunction caused by MMC exposure was triggered mainly by DNA alkylation resulting in the genotoxic stress in the endothelial cells.

GLP-1 receptor expression in human internal thoracic arteries is dependent on low-grade inflammation potentially explaining the cardiovascular protective effect of GLP1-R agonists

Abstract Background Clinical research showed that glucagon-like peptide-1 receptor (GLP1R) agonists (GLP1RA) reduced the incidence of major cardiovascular events in diabetic patients. The protective effect was more noteworthy in patients with established cardiovascular disease, associated with chronic low-grade inflammation resulting in endothelial dysfunction and arterial remodeling and fibrosis. Despite the clinically proven cardiovascular benefit of GLP1RA, the expression pattern of GLP1R and its function in the human vasculature remain poorly studied. Aim This study investigated the expression of GLP1R and its role in internal thoracic arteries (ITA) from patients with coronary artery disease. Methods Human ITA were collected from patients (N=30) undergoing coronary artery bypass surgery at the University Hospital of Strasbourg. Gene expression levels were assessed using RT-qPCR, protein levels by Western blot analysis, in situ tissue localization of proteins by immunofluorescence (IF) staining, and the level of oxidative stress using dihydroethidium. Results ITA showed a substantial difference in GLP1R mRNA levels reaching up to 7-fold among patients. GLP1R mRNA levels were positively correlated with those of SLC5A1, SLC5A2, F3, AT1R, IL1B, IL6, TNFα, VCAM1 and NCF1, and negatively with NOS3 mRNA levels. High GLP1R expressing ITA showed high levels of phosphorylated p65 NF-κB, cell adhesion molecule VCAM1, members of the angiotensin system (ACE1 and AT1R), remodeling and fibrotic markers (MMP9, MMP2, TGFβ) and a low level of eNOS, whereas the contrary was observed for low GLP1R expressing ITA. IF staining showed that GLP1R signals were predominantly observed in the endothelium of low GLP1R expressing ITA and in the vascular smooth muscle of high GLP1R expressing ITA. Prominent CD68 staining associated with the endothelium and the perivascular adipose tissue were observed in high but not low GLP1R expressing ITA. High GLP1R expressing ITA showed increased levels of oxidative stress, which were inhibited by the antioxidant N-acetylcysteine (NAC), NADPH oxidase inhibitor (VAS-2870), ACE inhibitor (perindoprilat), AT1R antagonist (losartan), TNF-α receptor neutralizing antibody (infliximab), selective SGLT2 inhibitor (empagliflozin), dual SGLT1/2 inhibitor (sotagliflozin) and by GLP1R agonists (liraglutide and semaglutide) with inhibitory effects amounting to about 50 to 75%. Conclusion These findings indicate that GLP1R expression levels in human ITA are dependent on low-grade inflammation and linked to endothelial dysfunction, pro-thrombotic, pro-remodeling and pro-fibrotic responses. Furthermore, they were associated with increased level of oxidative stress sensitive to inhibitors of either the local angiotensin system, SGLT2, TNFα and agonists of GLP1R. Thus, the cardiovascular beneficial effects of GLP1R agonists might be attributable to their ability to reduce the pro-oxidant stimulatory signal related to low-grade inflammation. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Frency Society of Vascular Medicine (SFMV)

Are ovine and porcine carotid arteries equivalent animal models for experimental cardiac surgery: A quantitative histological comparison

BackgroundCoronary artery bypass grafting (CABG) is a common cardiac surgery. Manufacturing small-diameter (2–5 mm) vascular grafts for CABG is important for patients who lack first-choice autologous arterial, or venous conduits. Ovine and porcine common carotid arteries (CCAs) are used as large animal models for in vivo testing of newly developed tissue-engineered arterial grafts. It is unknown to what extent these models are interchangeable and whether the left and right arteries of the same subjects can be used as experimental controls. Therefore, we compared the microscopic structure of paired left and right ovine and porcine CCAs in the proximodistal direction and compared these animal model samples to samples of human coronary arteries (CAs) and human internal thoracic arteries (ITAs). MethodsWe compared the histological composition of whole CCAs of sheep (n = 22 animals) with whole porcine CCAs (n = 21), segments of human CAs (n = 21), and human ITAs (n = 21). Using unbiased sampling and stereological methods, we quantified the fractions of elastin, total collagen, type I collagen, type III collagen, smooth muscle actin (SMA) and chondroitin sulfate (CS) A, B, and C. We also quantified the densities and distributions of nuclear profiles, nervi vasorum and vasa vasorum as well as the thickness of the intima-media and total wall thickness. ResultsThe differences between the paired samples of left and right CCAs in sheep were substantially greater than the differences in laterality in porcine CCAs. The right ovine CCAs had a smaller fraction of elastin (p < 0.001), greater fraction of SMA (p < 0.01), and greater intima-media thickness (p < 0.001) than the paired left side CCAs. In pigs, the right CCAs had a greater fraction of elastin (p < 0.05) and a greater density of vasa vasorum in the media (p < 0.001) than the left-side CCAs. The fractions of elastin and CS decreased and the fraction of SMA increased in the proximodistal direction in both the ovine (p < 0.001) and porcine (p < 0.001) CCAs. Ovine CCAs had a muscular phenotype along their entire length, but porcine CCAs were elastic-type arteries in the proximal segments but muscular type arteries in middle and distal segments. The CCAs of both animals differed from the human CAs and ITAs in most parameters, but the ovine CCAs had a comparable fraction of elastin and CS to human ITAs. ConclusionsFrom a histological point of view, ovine and porcine CCAs were not equivalent in most quantitative parameters to human CAs and ITAs. Left and right ovine CCAs did not have the same histological composition, which is limiting for their mutual equivalence as sham-operated controls in experiments. These differences should be taken into account when designing and interpreting experiments using these models in cardiac surgery. The complete morphometric data obtained by quantitative evaluation of arterial segments were provided to facilitate the power analysis necessary for justification of the minimum number of samples when planning further experiments. The middle or distal segments of ovine and porcine CCAs remain the most realistic and the best characterized large animal models for testing artificial arterial CABG conduits.

Antispastic Effect of Fasudil and Cocktail of Fasudil and Nitroglycerin in Internal Thoracic Artery

BackgroundSpasm of arterial grafts in coronary artery bypass grafting is a clinical problem and can occasionally be lethal. Perioperative spasm in the internal thoracic artery (ITA) and coronary arteries occurs in 0.43% of patients. This study aimed to investigate the antispastic effect of a RhoA/Rho-kinase (Rho-associated coiled-coil-containing protein kinase [ROCK]) inhibitor (fasudil) with and without nitroglycerin in combination in the ITA. MethodsIsolated human ITA rings taken from 68 patients who were undergoing coronary bypass were studied in a myograph. Cumulative concentration-relaxation curves for fasudil (−9 to −3.5 log M) were established in the ITA, which was precontracted with potassium chloride or U46619. The inhibitory effect of fasudil (−6.3 or −5.3 log M) or fasudil in combination with nitroglycerin were also tested. The ROCK2 protein was measured by Western blot. ResultsFasudil caused similar relaxation in ITA rings contracted by potassium chloride or U46619. Pretreatment with −5.3 log M fasudil significantly depressed contraction induced by potassium chloride (P = .004 vs control; P = .017 vs −6.3 log M) and U46619 (P = .010 vs control; P = .041 vs. −6.3 log M). Fasudil in combination with nitroglycerin had more effect and more rapid and sustained relaxation than either vasodilator alone. Fasudil caused a decrease of ROCK2 protein content (P = .014). ConclusionsFasudil fully relaxes some vasoconstrictor-induced contraction and decreases ROCK2 protein content in the ITA. The combination of fasudil and nitroglycerin has a superior effect than either vasodilator alone. The new cocktail solution composed of fasudil and nitroglycerin (pH 7.4) has effective antispastic action and may prove to be a new antispastic method for arterial conduits during coronary bypass surgery.

Vasorelaxing properties of the perivascular tissue of the human radial artery.

Perivascular adipose tissue (PVAT) surrounding the human internal thoracic artery exhibits anticontractile and vasorelaxing properties associated with the adipocyte-derived relaxing factor (ADRF). The goal of our study was to assess if perivascular tissue of the human radial artery (RA) also exhibits such anticontractile/vasorelaxant properties. It could be especially relevant in preventing RA spasms. The study was performed on isolated segments of human pedicled RA. Its skeletonized fragments were suspended on stainless steel wire hooks and gradually contracted with serotonin to establish the concentration-effect relationship in the presence/absence of PVAT. Skeletonized arterial segments were precontracted with a single dose of 10-6 M serotonin (EC80). The 5-ml PVAT aliquots (from PVAT incubated in Krebs-Henseleit solution) were transferred to the RA tissue bath resulting in its relaxation. Subsequently, we investigated if ADRF is dependent on endothelial vasorelaxants (nitric oxide and prostacyclin). We attempted to find the potassium channel responsible for mediating the activity of ADRF using different potassium channel blockers. RA without PVAT contracted more strongly in response to serotonin compared to RA with PVAT [Emax: 108.3 (20.2) vs 76.1 (13.5) mN]. The PVAT aliquot relaxed precontracted RA rings at 43% (2.4%) [72.2 (15.6) to 41.0 (5.6) mN]. ADRF is independent of endothelial vasorelaxants; hence, the addition of NG-monomethyl-l-arginine and indomethacin did not change the vasorelaxant response. Neither of the potassium channel blockers participated in the activity of ADRF. PVAT of human RA exhibits anticontractile/vasorelaxant properties that are inherently associated with ADRF secretion. We confirmed the endothelial-independent mechanism of the activity of ADRF. However, we failed to find the potassium channel responsible for the action of ADRF.

Ultrastructure of neointima of native and artificial elements of the blood circulatory system

To compare the neointima structure in conduits for coronary bypass grafting, bioprosthetic heart valves, tissue-engineered vascular grafts, and metal stents. The objects of the study were the fragments of the human internal thoracic artery, experimental biodegradable vascular prostheses, leaflets of xenopericardial bioprostheses of heart valves, and fragments of stented vessels. Tissue samples were fixed in formalin and post-fixed in osmium tetroxide. After dehydration and epoxy resin embedding, the samples were ground and polished. Samples were counterstained with uranyl acetate and lead citrate and visualized by means of backscattered scanning electron microscopy. Neointimal pattern in all samples was similar. Neointima was comprised of endothelial cells, smooth muscle cells, fibroblasts, and the extracellular matrix. Endothelial cells showed significant diversity both between different elements of the circulatory system and within the same tissue, having either elongated or polygonal shape. Adhesion of leukocytes testified to the endothelial cell activation. In the absence of inflammation in the superficial layer of the neointima, the arrangement of smooth muscle cells and extracellular matrix fibers was parallel to the endothelium. Clusters of foam cells were frequently detected around the neointimal layers with solid inclusions (metal stents or calcium deposits). Thickening of the neointima was accompanied by the presence of capillaries and capillary-like structures. Neointima formation is a typical response to the damage inflicted to the elements of the circulatory system. Neointima underwent a constant remodeling characterized by an altered cellular composition, macrophage invasion, neovascularization, and calcification.

Effects of Remote Ischaemic Preconditioning on the Internal Thoracic Artery Nitric Oxide Synthase Isoforms in Patients Undergoing Coronary Artery Bypass Grafting.

Remote ischaemic preconditioning (RIPC) is a medical procedure that consists of repeated brief periods of transient ischaemia and reperfusion of distant organs (limbs) with the ability to provide internal organ protection from ischaemia. Even though RIPC has been successfully applied in patients with myocardial infarction during coronary revascularization (surgery/percutaneous angioplasty), the underlying molecular mechanisms are yet to be clarified. Thus, our study aimed to determine the role of nitric oxide synthase (NOS) isoforms in RIPC-induced protection (3 × 5 min of forearm ischaemia with 5 min of reperfusion) of arterial graft in patients undergoing urgent coronary artery bypass grafting (CABG). We examined RIPC effects on specific expression and immunolocalization of three NOS isoforms — endothelial (eNOS), inducible (iNOS) and neuronal (nNOS) in patients’ internal thoracic artery (ITA) used as a graft. We found that the application of RIPC protocol leads to an increased protein expression of eNOS, which was further confirmed with strong eNOS immunopositivity, especially in the endothelium and smooth muscle cells of ITA. The same analysis of two other NOS isoforms, iNOS and nNOS, showed no significant differences between patients undergoing CABG with or without RIPC. Our results demonstrate RIPC-induced upregulation of eNOS in human ITA, pointing to its significance in achieving protective phenotype on a systemic level with important implications for graft patency.

Effects of M-1, a Major Metabolite of Sarpogrelate, on 5-HT-Induced Constriction of Isolated Human Internal Thoracic Artery.

Sarpogrelate, a selective 5-hydroxytryptamine (5-HT)2A receptor antagonist, inhibits 5-HT-induced platelet aggregation and vasoconstriction. It improves ischemic symptoms in patients with arteriosclerosis obliterans. M-1 is a major metabolite of sarpogrelate, and has been reported to show a higher affinity for the 5-HT2A receptor on platelets than sarpogrelate. However, the effects of M-1 on 5-HT-induced constrictive response in human blood vessels have not been investigated. The internal thoracic artery (ITA) is the key conduit for coronary artery bypass grafting (CABG). 5-HT has been implicated as playing an important role in the pathogenesis of vasospasm. Thus, in the present study, the effects of M-1 on 5-HT-induced vasoconstriction were examined in isolated human endothelium denuded ITA. M-1 inhibited 5-HT-induced vasoconstriction in a concentration-dependent manner. At the highest concentration, M-1 almost completely inhibited the 5-HT-induced vasoconstriction. Expression of 5-HT2A and 5-HT1B receptor proteins in the membrane fraction of ITA smooth muscle cells was confirmed by Western blot analysis. Individually, supramaximal concentrations of sarpogrelate and SB224289, a selective 5-HT1B receptor antagonist, only partially inhibited the 5-HT-induced vasoconstriction. However, simultaneous pretreatment with both these antagonists almost completely inhibited the 5-HT-induced vasoconstriction. The inhibitory effect of M-1 pretreatment mimicked the inhibitory effect of simultaneous pretreatment with sarpogrelate and SB224289. These results suggest that M-1 has antagonistic effects not only on the 5-HT2A receptor but also on the 5-HT1B receptor in human ITA smooth muscle cells. M-1 may be useful as a lead compound for the development of drugs for the treatment of 5-HT-induced vasospasms in CABG.

Mitomycin C induced genotoxic stress in endothelial cells is associated with differential expression of proinflammatory cytokines

Mitomycin C (MMC) is an alkylating chemotherapy drug that causes DNA crosslinking resulting in transcription arrest and apoptosis. DNA crosslinking is a critical damage to DNA that can be caused not only by MMC and other antitumor drugs, but also by various environmental and anthropogenic endo- and exogenous agents. Mammalian cells exposed to alkylating mutagens are characterized by severe genotoxic stress. Somatic mutations and genotoxic stress may lead to endothelial dysfunction, which is the initial stage of atherosclerosis, a leading cause of morbidity and mortality worldwide. Here we studied DNA damage, protein secretion and gene expression of IL6 and IL8 in primary human coronary artery endothelial cells (HCAEC) and human internal thoracic artery endothelial cells (HITAEC) in vitro exposed to 500 ng/mL MMC. We observed an increase in levels of cytogenetic damage (micronuclei, nucleoplasmic bridges and nuclear buds) in MMC-treated cells compared to control cells. After 6 h incubation with MMC, both HCAEC and HITAEC displayed a decrease in IL8 concentration and the mRNA level of IL6 and IL8 compared to control cells. Removal of MMC from cultures after 6 h followed by 24 h incubation of cells in complete growth media led to a sharp increase in secretion and gene expression of the studied cytokines in both HCAEC and HITAEC. Moreover, HCAEC were more susceptible to mutagenic exposure compared to HITAEC. These findings suggest that the MMC-induced genotoxic stress in endothelial cells derived from different arteries is associated with differential secretion and gene expression of proinflammatory cytokines IL6 and IL8.

Vascular activity of infusion and fractions of Cymbopogon citratus (DC) Stapf. in human arteries

Ethnopharmacological relevanceCymbopogon citratus (DC.) Stapf has been traditionally used mainly for inflammatory diseases and hypertension. However, the mechanisms underlying its vascular activity remain to be fully characterized and the fractions responsible for its cardiovascular activity are still unknown. Aim of the studyIn this study, we aimed to assess the vascular activity of Cymbopogon citratus in human arteries and to study the role of cyclooxygenase in its vasorelaxant effects. Materials and methodsVascular effects of leaves infusion and three fractions (phenolic acids, flavonoids and tannins) were studied using distal segments of human internal thoracic arteries harvested from patients undergoing coronary revascularization, which were mounted as rings in tissue organ baths and maintained at 37 °C in Krebs Henseleit buffer. The effect on basal vascular tone, the effect on the noradrenaline-induced contraction and the vasorelaxant effects were assessed. The role of cyclooxygenase was evaluated with indomethacin. ResultsOur results showed a mild effect on the basal vessel tone of the infusion. A significant inhibition on the adrenergic-mediated vasoconstriction was observed for the infusion (0.0002 mg/mL) and the flavonoid fraction (0.2 mg/mL), despite a potentiation was observed in some conditions. A vasorelaxant effect was observed for both the infusion (6.46% of maximal relaxation) and the tannin fraction (26.91% of maximal relaxation, P < 0.05 vs. infusion). Incubation with indomethacin (10 μM) elicited a decrease in the vasorelaxation to the infusion (P < 0.05). ConclusionsThese results suggest that cyclooxygenase may be involved in the vasorelaxation to the infusion of Cymbopogon citratus and that tannins are the compound fraction mainly responsible for this vasorelaxation.

Histological mapping of porcine carotid arteries — An animal model for the assessment of artificial conduits suitable for coronary bypass grafting in humans

BackgroundUsing animal models in experimental medicine requires mapping of their anatomical variability. Porcine common carotid arteries (CCA) are often preferred for the preclinical testing of vascular grafts due to their anatomical and physiological similarity to human small-diameter arteries. Comparing the microscopic structure of animal model organs to their human counterparts reveals the benefits and limitations of translational medicine. MethodsUsing quantitative histology and stereology, we performed an extensive mapping of the regional proximodistal differences in the fractions of elastin, collagen, and smooth muscle actin as well as the intima-media and wall thicknesses among 404 segments (every 1 cm) of porcine CCAs collected from male and female pigs (n = 21). We also compared the microscopic structure of porcine CCAs with segments of human coronary arteries and one of the preferred arterial conduits used for the coronary artery bypass grafting (CABG), namely, the internal thoracic artery (ITA) (n = 21 human cadavers). ResultsThe results showed that the histological structure of left and right porcine CCA can be considered equivalent, provided that gross anatomical variations of the regular branching patterns are excluded. The proximal elastic carotid (51.2% elastin, 4.2% collagen, and 37.2% actin) transitioned to more muscular middle segments (23.5% elastin, 4.9% collagen, 54.3% actin) at the range of 2–3 centimeters and then to even more muscular distal segments (17.2% elastin, 4.9% collagen, 64.0% actin). The resulting morphometric data set shows the biological variability of the artery and is made available for biomechanical modeling and for performing a power analysis and calculating the minimum number of samples per group when planning further experiments with this widely used large animal model. ConclusionsComparison of porcine carotids with human coronary arteries and ITA revealed the benefits and the limitations of using porcine CCAs as a valid model for testing bioengineered small-diameter CABG vascular conduits. Morphometry of human coronary arteries and ITA provided more realistic data for tailoring multilayered artificial vascular prostheses and the ranges of values within which the conduits should be tested in the future. Despite their limitations, porcine CCAs remain a widely used and well-characterized large animal model that is available for a variety of experiments in vascular surgery.

Aging-related carcinoembryonic antigen-related cell adhesion molecule 1 signaling promotes vascular dysfunction.

Aging is an independent risk factor for cardiovascular diseases and therefore of particular interest for the prevention of cardiovascular events. However, the mechanisms underlying vascular aging are not well understood. Since carcinoembryonic antigen‐related cell adhesion molecule 1 (CEACAM1) is crucially involved in vascular homeostasis, we sought to identify the role of CEACAM1 in vascular aging. Using human internal thoracic artery and murine aorta, we show that CEACAM1 is upregulated in the course of vascular aging. Further analyses demonstrated that TNF‐α is CEACAM1‐dependently upregulated in the aging vasculature. Vice versa, TNF‐α induces CEACAM1 expression. This results in a feed‐forward loop in the aging vasculature that maintains a chronic pro‐inflammatory milieu. Furthermore, we demonstrate that age‐associated vascular alterations, that is, increased oxidative stress and vascular fibrosis, due to increased medial collagen deposition crucially depend on the presence of CEACAM1. Additionally, age‐dependent upregulation of vascular CEACAM1 expression contributes to endothelial barrier impairment, putatively via increased VEGF/VEGFR‐2 signaling. Consequently, aging‐related upregulation of vascular CEACAM1 expression results in endothelial dysfunction that may promote atherosclerotic plaque formation in the presence of additional risk factors. Our data suggest that CEACAM1 might represent an attractive target in order to delay physiological aging and therefore the transition to vascular disorders such as atherosclerosis.

Специфичная токсичность кальций-фосфатных бионов для культур венозных и артериальных эндотелиальных клеток человека

Цель исследования - оценка токсичности кальций-фосфатных бионов (КФБ) и магний-фосфатных бионов (МФБ) для культур эндотелиальных клеток. Методика. Эндотелиотоксичность бионов изучена при помощи добавления равных концентраций МФБ или КФБ к: 1) разреженным или конфлюэнтным культурам иммортализованных венозных эндотелиальных клеток человека линии EA.hy 926 с последующим культивированием в течение 24 ч или 4 ч соответственно; 2) конфлюэнтным культурам коммерческих первичных эндотелиальных клеток коронарной и внутренней грудной артерии человека с последующим культивированием в течение 24 ч. Эндотелиотоксические эффекты бионов оценивали при помощи сочетанного окрашивания клеток флюоресцентными красителями Hoechst 33342 и бромистым этидием, а также посредством колориметрического теста. Кроме того, методом проточной цитометрии оценивали пути и стадии гибели клеток вышеуказанных культур. Результаты. В отличие от МФБ, КФБ индуцировали гибель эндотелиальных клеток всех 3 линий путем апоптоза. Устойчивость культур к токсическому действию КФБ определялась степенью их конфлюэнтности (конфлюэнтные культуры более устойчивы чем разреженные) и типом клеточной линии (эндотелиальные клетки внутренней грудной артерии продемонстрировали большую устойчивость в сравнении с эндотелиальными клетками коронарной артерии). Заключение. Токсичность КФБ для культур эндотелиальных клеток специфична, то есть определяется их специфическим минеральным составом, а не общей для всех типов бионов корпускулярной природой. Добавление КФБ к конфлюэнтным культурам первичных артериальных эндотелиальных клеток и к иммортализованным венозным эндотелиальным клеткам вызывало их гибель, при этом экспозиция МФБ не оказывает значимого токсического действия. Эндотелиальные клетки внутренней грудной артерии менее чувствительны к воздействию КФБ в сравнении с эндотелиальными клетками коронарной артерии человека. Aim. To compare toxicity of calcium phosphate bions (CPB) and magnesium phosphate bions (MPB) for endothelial cells. Me-thods. To assess endothelial toxicity of the bions, we first added equal concentrations of either MPB or CPB to: 1) non-confluent or confluent cultures of immortalized human venous endothelial cells EA.hy 926 with the exposure time of 24 h or 4 h, respectively; 2) confluent cultures of commercially available primary human coronary artery and internal thoracic artery endothelial cells, with the exposure time of 24 h. Endothelial toxicity was then evaluated by combined Hoechst 33342 and ethidium bromide staining following fluorescence microscopy and by colorimetric cytotoxicity assay. In addition, we attempted to determine the pathway of bion-induced cell death utilizing flow cytometry. Results. In contrast to the MPB, CPB induced apoptosis of all studied endothelial cell lines. Resistance of endothelial cells to the CPB was defined by their confluence (confluent cultures demonstrated higher resistance), and cell type (internal thoracic artery endothelial cells were more resistant to the CPB as compared to the coronary artery endothelial cells). Conclusions. Endothelial toxicity of the CPB is defined by their specific mineral composition but not by their corpuscular nature, which is common for all nanoparticles. Addition of the CPB to the confluent cultures of primary human arterial cells and to immortalized human venous endothelial cells evoked their death. On the contrary, exposure to the MPB did not cause any toxic effects. Human internal thoracic artery endothelial cells are more resistant to the CPB in comparison with coronary artery endothelial cells.

Histomorphometric analysis of the human internal thoracic artery and relationship with cardiovascular risk factors.

In this study, we aimed at performing a histomorphometric analysis of human left internal thoracic artery (ITA) samples as well as at correlating the histomorphometric findings with the clinical profile, including risk factors and medication. Distal segments of ITA were obtained from 54 patients undergoing coronary artery bypass grafting. Histological observation was performed in paraffin-embedded transverse sections of ITA through four staining protocols: hematoxylin-eosin, van Gieson, Masson’s trichrome and von Kossa. Morphometric analysis included the intimal width (IW), medial width (MW) and intima/media ratio (IMR). No overt atherosclerotic lesions were observed. Mild calcifications were observed across the vascular wall layers in almost all samples. Multivariable linear regression analysis showed associations between IW and IMR and the following clinical variables: age, gender, kidney function expressed as eGFR and myocardial infarction history. Age (odds ratio = 1.16, P = 0.004), female gender (odds ratio = 11.34, P = 0.011), eGFR (odds ratio = 1.03, P = 0.059) and myocardial infarction history (odds ratio = 4.81, P = 0.040) were identified as the main clinical predictors for intimal hyperplasia. Preatherosclerotic lesions in ITA samples from patients undergoing coronary revascularization were associated not only with classical cardiovascular risk factors such as age and gender, but also with other clinical variables, namely kidney function and myocardial infarction history.

The effect of M-1, a major metabolite of sarpogrelate, on 5-hydroxytryptamine-mediated vasoconstriction in isolated human internal thoracic artery

The effect of M-1, a major metabolite of sarpogrelate, on 5-hydroxytryptamine-mediated vasoconstriction in isolated human internal thoracic artery

MDMA modulates 5-HT1-mediated contractile response of the human internal thoracic artery in vitro

3,4-Methylenedioxymethamphetamine (MDMA or “ecstasy”) is a popular recreational drug of abuse. In addition to its characteristic psychotropic effects, important cardiovascular effects have been described such as increased blood pressure and heart rate. MDMA was previously shown to behave as a partial agonist on 5-hydroxytryptamine (5-HT) receptors in the human internal thoracic artery in vitro, involving the 5-HT2A subtype. Here, we studied the interaction of MDMA (400, 800 and 1600 μM) with the following 5-HT receptor agonists: 5-carboxamidotryptamine (5-CT, full agonist for the 5-HT1, 5-HT2, 5-HT5, 5-HT6 and 5-HT7 receptors) and sumatriptan (selective 5-HT1B/1D receptors agonist). The results showed the ability of MDMA to influence the concentration-dependent response of 5-CT (97.3% of maximal reduction for 1600 μM of MDMA) and sumatriptan (72.43% of maximal reduction for 1600 μM of MDMA). The lower concentration of MDMA (400 μM) produced a significant potentiation of the response to sumatriptan thus suggesting an interaction of MDMA with the activation of 5-HT receptors, namely of the 5-HT1 subtype, in the peripheral vasculature. Together our results further support the importance of the affinity of MDMA to 5-HT receptors in the vascular effects of this drug.

Vasomotion as an oscillatory sign of functional impairment in the human internal thoracic artery: A study based on risk factors and vessel reactivity.

What is the central question of this study? Vasomotion has been viewed as a rhythmic oscillation of the vascular tone that is physiologically important for optimal tissue perfusion. Also, it has been studied primarily in the microcirculation. However, the precise underlying mechanisms and the physiological significance remain unknown. What is the main finding and its importance? Vasomotion is not specific to the microcirculation, as shown by our findings. In human arteries from patients undergoing cardiac surgery, an increased incidence was associated with endothelial dysfunction settings. Therefore, this oscillatory behaviour might be a signal of functional impairment and not of integrity. Vasomotion has been defined as the rhythmic oscillation of the vascular tone, involved in the control of the blood flow and subsequent tissue perfusion. Our aims were to study the incidence of vasomotion in the human internal thoracic artery and the correlation of this phenomenon with the clinical profile and parameters of vascular reactivity. In our study, vasomotion was elicited with a single-dose contractile stimulation of noradrenaline (10μm) in internal thoracic artery segments, from patients undergoing coronary artery bypass grafting, mounted in tissue organ bath chambers. The incidence was 29.1%. Vessel samples with vasomotion presented significantly higher contractility in response to both potassium chloride (maximal response or Emax of 7.65±5.81mN versus 4.52±3.73mN in control vessels, P=0.024) and noradrenaline (Emax of 7.60±5.93mN versus 2.96±4.41mN in control vessels, P<0.001). Predictive modelling through multivariable logistic regression analysis showed that female sex (odds ratio=9.82) and increasing maximal response to noradrenaline (odds ratio=1.19, per 1mN increase) were associated with a higher probability of the occurrence of vasomotion, whereas increasing kidney function (expressed as estimated glomerular filtration rate) was associated with a lower probability (odds ratio=0.97, per 1mlmin-1 (1.73m)-2 ]. Our results provide a characterization of the phenomenon of vasomotion in the internal thoracic artery and suggest that vasomotion might be associated with endothelial dysfunction settings, as determined by a multivariable analysis approach. Considering the associations observed in our results, vasomotion might be a signal of functional impairment and not of integrity.

Diabetes Mellitus Induces Hyperreactivity of 5-Hydroxytryptamine (5-HT)-Induced Constriction in Human Internal Thoracic Artery and Is Associated with Increase in the Membrane Protein Level of 5-HT&lt;sub&gt;2A&lt;/sub&gt; Receptor

Studies indicate that 5-hydroxytryptamine (5-HT) released from activated platelets in coronary artery bypass grafting (CABG) induces 5-HT2A receptor-mediated graft spasm. We previously reported that 5-HT-induced constriction of human endothelium-denuded saphenous vein (SV) was significantly augmented in patients with diabetes mellitus (DM) than in patients without DM (non-DM), without changes in the levels of the membrane-bound 5-HT2A receptor of their smooth muscle cells. Although the internal thoracic artery (ITA) is the key graft conduit for CABG, the effect of DM on the ITA graft spasm is still unclear. Therefore, in this study, we investigated the effect of DM on 5-HT-induced vasoconstriction and the level of membrane-bound 5-HT2A receptor in ITA grafts. 5-HT-induced constriction of the isolated human endothelial-denuded ITA was significantly higher in patients with DM than in patients without DM. In addition, the level of the 5-HT2A receptor in the membrane fraction of human ITA smooth muscle cells was significantly higher in patients with DM than in those without DM. These results demonstrate that DM is a risk factor for CABG in both venous and arterial conduits, and that it differentially affects the level of the membrane-bound 5-HT2A receptor in the venous and arterial smooth muscle cells.