Adventitia Of Arteries Research Articles

Nanomechanics and ultrastructure of the internal mammary artery adventitia in patients with low and high pulse wave velocity

The collagen-rich adventitia is the outermost arterial layer and plays an important biomechanical and physiological role in normal vessel function. While there has been a lot of effort to understand the role of the medial layer on arterial biomechanics, the adventitia has received less attention. In this study, we hypothesized that different ultrastructural and nanomechanical properties would be exhibited in the adventitia of the internal mammary artery (IMA) in patients with a low degree of arterial stiffening as compared to those with a high degree of arterial stiffening. Human IMA biopsies were obtained from a cohort of patients with arterial stiffening assessed via carotid-femoral PWV. Patients were grouped as low PWV (8.5 ± 0.7 ms−1, n = 8) and high PWV (13.4 ± 3.0 ms−1, n = 9). Peakforce QNM atomic force microscopy (AFM) was used to determine the nanomechanical and morphological properties of the IMA. The nano-scale elastic modulus was found to correlate with PWV. We show for the first time that nano-scale alterations in adventitial collagen fibrils in the IMA are evident in patients with high PWV, even though the IMA is not involved in the carotid-femoral pathway. Our approach provides new insight into systemic structure-property changes in the vasculature, and also provides a method of characterizing small biopsy samples to predict the development of arterial stiffening. Statement of SignificanceArterial stiffening occurs as part of the natural aging process and is strongly linked to cardiovascular risk. Although arterial stiffening is routinely measured in vivo, little is known about how localised changes in artery structure and biomechanics contributes to in vivo arterial stiffening. This study focusses on the role of the outermost layer of arteries, the adventitia, in arterial stiffening. The study provides data on nano-scale changes in collagen fibril structure and mechanical properties in the adventitia and shows how it relates to in vivo stiffness measurements in the vascular system. This is the first study to link in vivo arterial stiffening with nanomechanical changes in artery biopsy samples. Hence, this approach could be used to develop new diagnostic methods for vascular disease.

PULMONARY CELL STAINED IN A RAT MODEL OF FAT EMBOLISM FOR RENIN AND PRORENIN ARE INCREASED AFTER ALISKIREN TREATMENT, WHICH AMELIORATES THE FAT‐INDUCED INFLAMMATORY PROCESS

IntroductionFat Embolism (FE) induced in rats by IV injection of Triolein (T) results in pulmonary vasculitis, inflammation, and fibrosis (1). Captopril and losartan, two drugs acting on the renin angiotensin system, prevent this damage (2). Administration of the renin inhibitor aliskiren also ameliorates the lung's histopathological changes induced by T injections with findings present as early as 48 hours after injection (3). Aliskiren also reduced the number of mast cells observed after T injection (4). This study is aimed at assessing aliskiren's effect on both the presence of vasculitis and on the number of renin/prorenin stained cells in a rat model of FE.Materials and MethodsSprague‐Dawley rats (250–300g) were treated with 0.2 ml IV of T (n=18) or saline (n=4). One hour later the rats were divided into three groups with injections with 0.2 ml of saline, 50 mg/kg, and 100 mg/kg of aliskiren (n=6 per group). 48 hours later all subjects were necropsied after isoflurane anesthesia, lungs removed and fixed in 10% formalin with sections submitted for H&E, Trichrome, and Abscam specific antibodies for renin/prorenin cells (R/P). Two pathologists unaware of the slide identity took 10 photographs at random at 400× and counted the number of R/P stained cells.ResultsSections demonstrated lung arterial vasculitis, septal inflammation, and fibrosis which were evident after 48 hours. Renin‐Prorenin stained cells were present in all groups and mostly located in the arterial adventitia, the thickened septa and subpleura. R/P immunointense reactivity was observed in cells of different sizes and shapes; with some having small oval stained cytoplasm and nucleus, while others demonstrated larger cytoplasm and nucleus with less intense stain and diffuse cytoplasmic vacuoles. A significant increase was seen for the T‐saline group vs the controls (p=0.008) for the small cells, but not for the larger ones. The 50 mg dose of aliskiren did not reduce either cell numbers while the 100 mg dose however induced a marked reduction vs the T‐saline cells both for both small and large cells (p=0.007 and 0.012 respectively). The ratio of small vs large cells was approximately 75% vs 25% for all groups.ConclusionThe increase in R/P stained cells after FE may be related to an increase in pulmonary mast cell population as seen in other pathological conditions and underlines the RAS involvement in FE.Support or Funding InformationSupported by the Catherine T Geldmacher Foundation, St. Louis, MOThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Renin and Prorenin Stained Cells in the Hearts of Rats Subjected to Fat Embolism and Treated with Aliskiren, a Drug Ameliorating the Pulmonary Inflammatory Process

IntroductionFat embolism (FE) induced in rats by iv injection of triolein (T) caused pulmonary inflammation, fibrosis and vasculitis (1). Administration of renin inhibitor aliskiren ameliorates these organs histopathological damage as early as 48 hours after the injection (2). It also reduces the pulmonary number of the mast cells, a possible inflammatory mediator (3). The hearts of the same animals however showed only a mild but statistically significant increase of SMA1 (P<.005) at this interval time without vasculitis and inflammation (4) and without reduction of mast cells (5).Pulmonary expression of renin/prorenin stained cells is also increased after T injection and it may be potentially related to the parallel mast cells increase (6). However, only the higher dose of aliskiren induced a reduction of these stained sells after T treatment (7).Study is aimed at assessing aliskiren effect on both vasculitis and number of renin/prorenin stained cells in the hearts of the same T treated animals.MethodsSprague‐Dawley rats (250–300g) were treated with 0.2 ml iv of T (n=18) or saline (n=4). One hour later the injected rats were divided into three groups each of them receiving ip 0.2 ml of saline, 50 mg/kg, and 100 mg/kg of aliskiren (n=6 per group). Saline injected rats received 0.2 ml of saline. 48 hours later all subjects were necropsied after isoflurane anesthesia, hearts removed and fixed in 10% formalin with sections submitted for H&E Trichrome and an Abscam specific antibodies for renin/prorenin stained cells (R/P). Two pathologists unaware of the slide identity took 10 photographs at random at 400× and counted the number of R/P stained cells.ResultsHeart sections demonstrated collections of myocardial fibrils of uniform size and shape without significant inflammation or necrosis. The R/P immunostain highlighted the presence of multiple cells of varying sizes which were primarily allocated in the endocardial and subendocardial surfaces. None of the cells were seen in adventitia of coronary arteries thus showing difference with their location in lungs. Some animals had large number of myocardial R/P cells others had very few, statistically creating, a large standard deviation. Increase of R/P cells was seen after T injection with even more cells after aliskiren treatment in addition to T. The increase was related to their different aliskiren doses. So that after 100 mg of aliskiren +T the cells were twice as many as those ones of controls (192 +/− 84 SD vs 104 +/− 59). The large standard deviation did not make the difference significant.ConclusionsThe study confirms the previously reported histopathological difference of the T induced damage of lungs and hearts. Size and shape of the cells are similar in both organs. Location varies. R/P cells increase both in hearts and lungs after T injection and their location differs. Aliskiren didn't reduce in the heart the R/P cells number as seen in the lungs of the same treated animals. Such difference may be related to a different organ response to their renin angiotensin system.Support or Funding InformationCatherine T Geldmacher Foundation, St. Louis, MOThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Renal Nerve Stimulation as Procedural End Point for Renal Sympathetic Denervation.

Renal sympathetic denervation (RDN) as treatment option for hypertension has a strong rationale; however, variable effects on blood pressure (BP) have been reported ranging from non-response to marked reductions in BP. The absence of a procedural end point for RDN is one of the potential factors associated with the variable response. Studies have suggested the use of renal nerve stimulation (RNS) to adequately address this issue. This review aims to provide an overview of the clinical and experimental data available regarding the effects of RNS in the setting of RDN. Animal studies have shown that high-frequency electrical stimulation of the sympathetic nerves in the adventitia of the renal arteries elicits an increase in BP and leads to an increased norepinephrine spillover as a marker of increased sympathetic activity and these effects of stimulation were attenuated or blunted after RDN. In a human feasibility study using RNS both before and after RDN, similar BP responses were observed. Moreover, in patients with resistant hypertension, RNS-induced changes in BP appeared to be correlated with 24-h BP response after RDN. These data suggest that RNS is a useful tool to identify renal sympathetic nerve fibers in patients with treatment-resistant hypertension undergoing RDN, and to predict the likely effectiveness of RDN treatments. In acute procedural settings both in animal and human models, RNS elicits increase in BP and HR before RDN and these effects are blunted after RDN. Up to now, there is preliminary evidence that the RNS-induced BP changes predict 24-h ABPM outcome at follow-up in patients with resistant hypertension. Of note, studies are small sized and results of large trials comparing conventional RDN to RNS-guided RDN are warranted.

Cerebral infarction caused by accidental incarceration of aneurysm-adjacent branches with temporary clips

Objective To explore the potential reasons of cerebral infarction caused by accidental incarceration of aneurysm-adjacent branches with temporary clips, and to give guidance to the appropriate application of temporary clips. Methods A retrospective analysis was conducted on the clinical data of 10 patients with accidental incarceration of branches of parent artery or aneurysm-adjacent perforator vessels who were admitted to Department of Neurosurgery of Fuzhou General Hospital from January 2004 to December 2016. Under microscopes, we observed the definite lesions of branches and perforator vessels during the procedures, features of temporary clips and the intraoperative procedure, and postoperative cerebral infarction with varying degrees in corresponding territories. Two cases of posterior communicating artery aneurysm and 2 cases of carotid bifurcation aneurysm were found on the extracranial superior mesenteric artery adventitia with varying degrees of atherosclerosis, misclipping occurred at the anterior pre-choroidal artery, recurrent artery of Heubner and lenticulostraiate artery. For 4 cases of anterior communicating artery aneurysms and 2 cases of middle cerebral artery aneurysm, mis-clipping was found at A1 or A2 and M1 segments adjacent to perforation. Results Among the 10 patients, CT review 2-4 days post surgery demonstrated cerebral infarction with varying degrees adjacent to the aneurysm branches, perforating branch of blood supply. Disturbance of consciousness occurred in 2 cases. Compared with preoperative state, short-term significant decrease in strength of limb muscles was observed in 5 cases, incomplete motor aphasia in 1 and asymptomatic cerebral infarction in 2. At follow-up ranging from 4 months to 3 years, 2 cases reported dementia and 2 cases had permanent hemiplegia, out of which 3 were disabling and needed long-term care. Conclusions Cerebral infarction caused by accidental incarceration of branches or perforator vessels with temporary clips could be related not only to the incarceration duration, age and vascular sclerosis, but also to the over-contraction of small blood vessels and the closing force of a temporary clip. Therefore, caution should be warranted regarding those factors in the use of temporary clips. Key words: Intracranial aneurysm; Vascular system injuries; Therapeutic occlusion; Brain infarction

Four-day pulse of sodium cromoglycate modulates pulmonary vessel wall remodeling during 21-day hypoxia in rats

ABSTRACTAim of the study: Remodeling of pulmonary resistance arteries in rats due to 4-day hypoxia could be successfully suppressed by sodium cromoglycate. In this study, we tested the difference in the suppression between two distinct time patterns of cromoglycate administration during 21-day hypoxia. In the experiment, we focused on some details in both smooth muscle cells and extracellular matrix of pulmonary arterial walls. Methods: During 21-day hypoxia, rats were treated with sodium cromoglycate either in the first four days or in the last four days. The first four days were chosen to test efficiency of an initial pulse of cromoglycate to suppress pulmonary vascular remodeling. The last four-day administration tested possibility to block remodeling post hoc. Results: Initial pulse reduced and modified remodeling in all levels of pulmonary arteries, which comprises neomuscularization of prealveolar arteries, asymmetrical hypertrophy of tunica media in muscular pulmonary arteries and hypertrophy of tunica media and tunica adventitia in large conduit arteries. Terminal pulse had only negligible effect. Conclusions: Only the initial cromoglycate therapy led to significant morphological suppression of remodeling. We therefore assume important role of initial remodeling influencing during long time hypoxia experiment.

Colonic Adventitial Fibromuscular Dysplasia: A Nonspecific Arteriopathy Associated With Hirschsprung Disease and Other Obstructive Disorders.

Background Smooth muscle differentiation ("adventitial fibromuscular dysplasia," AFD) was purported as specific to arteries in the transition zone of Hirschsprung disease (HSCR) patients. We investigated AFD in an HSCR population and controls and consider the pathogenesis and significance of the vascular pathology. Design Vascular histology in sections from colonic HSCR resections (n = 55) was compared with age- and site-matched controls with (n = 19) and without (n = 28) non-HSCR obstructive conditions. Vascular pathology was mapped, and correlations were sought between the vascular findings and bowel distension, inflammation, neuromuscular anatomy, preoperative clinical variables, and postsurgical complications. Results One of 2 forms of AFD was identified in 42% (23/55) of the HSCR resections: the previously described "mature" form with adventitial bundles of differentiated smooth muscle cells (7/23, all submucosal) and a newly described "immature" AFD characterized by densely packed myofibroblasts in the arterial adventitia (16/23, 3 submucosal, 3 serosal, and 10 both). Adventitial inflammation and/or medial necrosis was present in the immature form (6/16). Mature submucosal AFD was present in 2/28 (7.1%) nonobstructive and 5/19 (26%) obstructive non-HSCR controls ( P = .10). Immature AFD was only found in less than 1-month-olds, and mature AFD only in older patients, including the 7 affected controls. AFD did not correlate with sex, syndromic status, length of the aganglionic segment, or postoperative complications. AFD was present in grossly dilated (17/23) and narrowed (10/23) regions and in the aganglionic (2/23), ganglionic (14/23), or both (7/23) segments. In several cases, AFD existed proximal to the histological transition zone. Conclusion AFD occurs in HSCR and other obstructive conditions but is significantly less common in the colons of patients with no history of dysmotility. The pathology likely progresses from a reversible accumulation of myofibroblasts in neonates to a stable population of mature smooth muscle cells. The distribution of vascular lesions does not correlate with neuropathological findings and suggests a nonspecific form of vascular injury, possibly related to bowel distension. AFD in HSCR resections has not been shown to be clinically significant and should not influence management.

Docosahexaenoic acid inhibits monocrotaline-induced pulmonary hypertension via attenuating endoplasmic reticulum stress and inflammation.

Endoplasmic reticulum (ER) stress and inflammation contribute to pulmonary hypertension (PH) pathogenesis. Previously, we confirmed that docosahexaenoic acid (DHA) could improve hypoxia-induced PH. However, little is known about the link between DHA and monocrotaline (MCT)-induced PH. Our aims were, therefore, to evaluate the effects and molecular mechanisms of DHA on MCT-induced PH in rats. Rat PH was induced by MCT. Rats were treated with DHA daily in the prevention group (following MCT injection) and the reversal group (after MCT injection for 2 wk) by gavage. After 4 wk, mean pulmonary arterial pressure (mPAP), right ventricular (RV) hypertrophy index, and morphological and immunohistochemical analyses were evaluated. Rat pulmonary artery smooth muscle cells (PASMCs) were used to investigate the effects of DHA on cell proliferation stimulated by platelet-derived growth factor (PDGF)-BB. DHA decreased mPAP and attenuated pulmonary vascular remodeling and RV hypertrophy, which were associated with suppressed ER stress. DHA blocked the mitogenic effect of PDGF-BB on PASMCs and arrested the cell cycle via inhibiting nuclear factor of activated T cells-1 (NFATc1) expression and activation and regulating cell cycle-related proteins. Moreover, DHA ameliorated inflammation in lung and suppressed macrophage and T lymphocyte accumulation in lung and adventitia of resistance pulmonary arteries. These findings suggest that DHA could protect against MCT-induced PH by reducing ER stress, suppressing cell proliferation and inflammation.

Development of fusiform aneurysms induced by topical application of elastase in a rabbit model

BackgroundResearch on the etiology and pathophysiology of fusiform aneurysm has been impeded due to the inability to collect fusiform aneurysm specimens. We aim to resolve this through the development of a novel fusiform aneurysm model in rabbits.MethodsSixty New Zealand White rabbits were divided into ten groups (n = 6 per group): groups A, B, C, D, E and groups a, b, c, d, e. Elastase, at a concentration of 0, 0.5, 1, 2.5 and 5 U/μL respectively was administered to each rabbit to incubate their carotid arteries. Three weeks later, angiography, histomorphometry, immunohistochemistry and immunofluorescent were performed.ResultsHeparin administration is indispensable. No thrombosis was observed in groups A, B, C, D and E, whereas, increased thromboembolism occurred in groups a, b, c, d and e. Based on the size and wall thickness of aneurysms specimens, 5 U/μL was the optimal concentration of elastase to induce fusiform aneurysms. At 5 U/μL, the intraluminal carotid diameter increased significantly from 2.50 ± 0.32 mm to 3.11 ± 0.55 mm (p < 0.01). The wall thickness significantly reduced from 176.0 ± 39.8 μm to 39.7 ± 14.6 μm (p < 0.01) post aneurysm induction. The histolopathological evaluation revealed the elastic lamina and the smooth muscle cell’s lamina were markedly attenuated and the intimal endothelial lamina became thin or even absent.ConclusionsOur research demonstrates that intracranial fusiform aneurysm could be modeled in rabbit carotid artery adventitia incubation by porcine pancreatic elastase.

Maternal uterine artery VEGF gene therapy for treatment of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a serious pregnancy complication affecting approximately 8% of all pregnancies. The aetiology is believed to be insufficient maternal uteroplacental perfusion which prevents adequate nutrient and oxygen availability for the fetus. There is no treatment that can improve uteroplacental perfusion and thereby increase fetal growth in the uterus.Maternal uterine artery gene therapy presents a promising treatment strategy for IUGR, with the use of adenoviral vectors encoding for proteins such as Vascular Endothelial Growth Factor (VEGF) demonstrating improvements in fetal growth and neonatal outcome in preclinical studies. Mechanistically, maternal VEGF gene therapy delivered to the uterine arteries increases uterine blood flow and enhances vascular relaxation short term, while reducing vascular contractility long term. It also leads to vascular remodeling with increased endothelial cell proliferation in the perivascular adventitia of uterine arteries. Safety assessments suggest no vector spread to the fetus and no adverse risk to the mother or fetus; a clinical trial is in development. This article assesses research into VEGF maternal uterine artery directed gene therapy for IUGR, investigating the use of transgenes and vectors, their route of administration in obstetrics, and the steps that will be needed to take this treatment modality into the clinic.

Resliced image space construction for coronary artery collagen fibers.

Collagen fibers play an important role in the biomechanics of the blood vessel wall. The objective of this study was to determine the 3D microstructure of collagen fibers in the media and adventitia of coronary arteries. We present a novel optimal angle consistence algorithm to reform image slices in the visualization and analysis of 3D collagen images. 3D geometry was reconstructed from resliced image space where the 3D skeleton was extracted as the primary feature for accurate reconstruction of geometrical parameters. Collagen fibers (range 80–200) were reconstructed from the porcine coronary artery wall for the measurement of various morphological parameters. Collagen waviness and diameters were 1.37 ± 0.19 and 2.61 ± 0.89 μm, respectively. The biaxial distributions of orientation had two different peaks at 110.7 ± 25.2° and 18.4 ± 19.3°. Results for width, waviness, and orientation were found to be in good agreement with manual measurements. In addition to accurately measuring 2D features more efficiently than the manual approach, the present method produced 3D features that could not be measured in the 2D manual approach. These additional parameters included the tilt angle (5.10 ± 2.95°) and cross-sectional area (CSA; 5.98 ± 3.79 μm2) of collagen fibers. These 3D collagen reconstructions provide accurate and reliable microstructure for biomechanical modeling of vessel wall mechanics.

Carotid stiffness, extra-media thickness and visceral adiposity in young adults

Background and aimsCarotid extra-media thickness (EMT) encompasses arterial adventitia and perivascular adipose tissue (PAT). Adventitial remodeling and PAT may contribute independently to functional (stiffness) and structural (remodeling) changes in artery wall properties. Visceral adiposity may contribute to PAT, thereby affecting artery stiffness. We investigated the relationships between carotid artery stiffness, EMT, and visceral adiposity in young, healthy individuals. Methods135 healthy males (20 ± 2 yr, body mass index [BMI] 24.8 ± 3.3 kg/m2) underwent anthropometric and vascular measures on two separate days. Visceral adiposity was assessed using waist circumference and sagittal abdominal diameter (SAD). Brachial and carotid systolic, diastolic, and pulsatile (PP) blood pressures were assessed using an oscillometric cuff and applanation tonometry, respectively. Carotid intima-media thickness (IMT) and EMT were assessed using Doppler ultrasound. Carotid artery stiffness was calculated as β-stiffness and calibrated to carotid pressures. ResultsSeparate stepwise multiple regression models demonstrated that carotid PP (β = 0.205) and EMT (β = 0.267) accounted for 12.6% of variance in β-stiffness, while carotid PP (β = 0.195) and SAD (β = 0.226) accounted for 10.5% of variance in EMT (p < 0.05). Mediation analyses revealed carotid PP partially mediated the relationship between a) EMT and β-stiffness, and b) SAD and EMT (p < 0.05). ConclusionsCarotid PP and EMT, but not IMT, are related to carotid β-stiffness. Carotid PP and visceral adiposity (SAD) are related to EMT. Carotid PP partially mediates the association between a) EMT and carotid β-stiffness, and b) SAD and EMT. Our findings suggest visceral adiposity may detrimentally affect subclinical markers of cardiovascular disease risk (carotid PP, EMT) and contribute to artery stiffness.

Galectin-3 mediates pulmonary vascular remodeling in hypoxia-induced pulmonary arterial hypertension

Pulmonary vascular adventitia serves as a key regulator of pulmonary vascular remodeling in the pathogenesis of pulmonary arterial hypertension (PAH). Excessive proliferation and differentiation of pulmonary adventitial fibroblasts (PAFs) are proven to be crucial in the pathogenesis of PAH. Galectin-3 (Gal-3) is known as a key fibroblasts activating factor which is involved in the fibrogenesis of several diseases, such as pulmonary fibrosis, vascular fibrosis, and heart failure. Therefore, we seek to investigate the potential role of Gal-3 in regulating PAF cells in the pathogenesis of PAH. Gal-3 plasma concentration was significantly higher in PAH patients. Gal-3 was upregulated in pulmonary artery adventitia of hypoxia-induced PAH rats. Inhibition of Gal-3 with N-Acetyl-D-lactosamine (N-Lac) ameliorated PAH and pulmonary vascular remodeling. Gal-3 can stimulate the proliferation, differentiation, and collagen synthesis of PAFs, which was reversed by N-Lac. Transforming growth factor β1 increased Gal-3 expression in PAFs, whereas N-Lac significantly suppressed transforming growth factor β1–induced proliferation, differentiation, and collagen synthesis of PAFs. Gal-3 serves as a critical regulator in the pathogenesis of PAH by regulating the proliferation, differentiation, and extracellular matrix deposition synthesis of PAFs. Inhibition of Gal-3 may represent a novel therapeutic target for PAH treatment.

The microvascular niche instructs T cells in large vessel vasculitis via the VEGF-Jagged1-Notch pathway.

Microvascular networks in the adventitia of large arteries control access of inflammatory cells to the inner wall layers (media and intima) and thus protect the immune privilege of the aorta and its major branches. In autoimmune vasculitis giant cell arteritis (GCA), CD4 T helper 1 (TH1) and TH17 cells invade into the wall of the aorta and large elastic arteries to form tissue-destructive granulomas. Whether the disease microenvironment provides instructive cues for vasculitogenic T cells is unknown. We report that adventitial microvascular endothelial cells (mvECs) perform immunoregulatory functions by up-regulating the expression of the Notch ligand Jagged1. Vascular endothelial growth factor (VEGF), abundantly present in GCA patients' blood, induced Jagged1 expression, allowing mvECs to regulate effector T cell induction via the Notch-mTORC1 (mammalian target of rapamycin complex 1) pathway. We found that circulating CD4 T cells in GCA patients have left the quiescent state, actively signal through the Notch pathway, and differentiate into TH1 and TH17 effector cells. In an in vivo model of large vessel vasculitis, exogenous VEGF functioned as an effective amplifier to recruit and activate vasculitogenic T cells. Thus, systemic VEGF co-opts endothelial Jagged1 to trigger aberrant Notch signaling, biases responsiveness of CD4 T cells, and induces pathogenic effector functions. Adventitial microvascular networks function as an instructive tissue niche, which can be exploited to target vasculitogenic immunity in large vessel vasculitis.

Collagen triple helix repeat containing-1 negatively regulated by microRNA-30c promotes cell proliferation and metastasis and indicates poor prognosis in breast cancer

BackgroundCollagen triple helix repeat containing-1 (CTHRC1), which was firstly identified overexpressed in the adventitia and neointima of injured rat arteries, could inhibit collagen expression and increase cell migration. It was then found to be ubiquitously expressed in numerous cell types such as fibroblasts and smooth muscle cells, and aberrantly up-regulated in several malignant tumors. However, the functional role of CTHRC1 and its related mechanism in breast cancer still remains unclear.MethodsCTHRC1 expressions in breast cancer tissues and cells were assessed by qRT-PCR, western blot and immunohistochemistry. The relative expression level of miR-134, miR-155, miR-30c and miR-630 in breast cancer cells respectively was detected by qRT-PCR. Wild type (Wt) and Mutant type (Mut) CTHRC1 3’UTR sequences were cloned into a psi-CHECK2 reporter vector, and the relative luciferase activity was detected by dual-luciferase reporter assay in indicated cells. The effect of ectopic expression of miR-30c or gain and loss of CTHRC1 on cell viability, cell proliferation, cell cycle progression and apoptosis, cell invasion and migration was respectively detected by CCK-8 assay, colony formation assay, flow cytometry analysis, transwell invasion/migration assay. Protein levels of β-catenin, active β-catenin, normal and phosphorylated form of GSK-3β were detected by western blot in indicated cells. Immunofluorescence staining of β-catenin was performed to observe nuclear localization.ResultsWe found CTHRC1 was frequently up-regulated in human breast cancer cells and tissues. Then our cohort study and further meta-analysis validated high expression of CTHRC1 was associated with aggressive clinicopathological features and poor clinical outcome of breast cancer patients. In addition, CTHRC1 promoted cell proliferation, invasion and migration and suppressed cell apoptosis in breast cancer, which might be by activating GSK-3β/β-catenin signaling and inhibiting Bax/Caspase-9/Caspase-3 signaling respectively; and these biological functions of CTHRC1 could be directly negatively regulated by miR-30c.ConclusionTaken together, we identified the role of miR-30c/CTHRC1 axis in breast cancer progression and demonstrated CTHRC1 may serve as a prognostic biomarker and therapeutic target for breast cancer.

Histology of the distal dural ring.

The distal dural ring (DDR) is a conserved intracranial anatomic structure marking the boundary point at which the internal carotid artery (ICA) exits the cavernous sinus (CS) and enters the subarachnoid space. Although the CS has been well described in a range of anatomic studies, to our knowledge no prior study has analyzed the histologic relationship between the ICA and DDR. Correspondingly, our objective was to assess the relationship of the DDR to the ICA and determine whether the DDR can be dissected from the ICA and thus divided, or can only be circumferentially trimmed around the artery. The authors examined ten fresh-frozen, adult cadaveric specimens. A standard frontotemporal craniotomy, orbito-optic osteotomy, and extradural anterior clinoidectomy was performed bilaterally. The cavernous ICA, DDR, and supraclinoid ICA were harvested as an en bloc specimen. Specimens formalin-fixed and paraffin-embedded prior to routine histochemical staining with hematoxylin and eosin and Masson trichrome. In all specimens, marked microscopic investment of the DDR throughout the ICA adventitia was noted. Dural collagen fibers extensively permeated the arterial layers superficial to the muscularis propria, with no evidence of a clear separation between the DDR and arterial adventitia. Histologic analysis suggests that the ICA and DDR are highly interrelated, continuous structures, and therefore attempted intraoperative dissection between these structures may carry an elevated risk of injury to the ICA. We correspondingly recommend careful circumferential trimming of the DDR in lieu of direct dissection in cases requiring mobilization of the clinoidal ICA. Clin. Anat. 30:742-746, 2017. © 2017Wiley Periodicals, Inc.

Recent advances in our understanding of giant cell arteritis pathogenesis.

Giant cell arteritis (GCA) is a granulomatous vasculitis affecting large arteries, especially the aorta and the extracranial branches of the external carotid artery. Its exact pathogenesis is not fully understood but major progress has been made in recent years, leading to new therapeutic targets like inhibition of the interleukin-6 pathway or the modulation of immune checkpoints. The cause of GCA has not been clearly identified but it is thought that GCA occurs on a genetic background and is triggered by unknown environmental factors that could activate and lead to the maturation of dendritic cells localized in the adventitia of normal arteries. These activated dendritic cells then produce chemokines which trigger the recruitment of CD4+ T cells, which in turn become activated, proliferate and polarize into Th1 and Th17 cells, which produce IFN-γ and IL-17, respectively. Exposed to IFN-γ, endothelial cells and vascular smooth muscle cells produce chemokines leading to the recruitment of further Th1 cells, CD8+ T cells and monocytes. The latter differentiate into macrophages, which, when persistently exposed to IFN-γ, form giant cells, the histological hallmark of GCA. With the contribution of vascular smooth muscle cells, immune cells then trigger the destruction and remodeling of the arterial wall, thus leading to the formation of a neo-intima resulting in progressive occlusion of the arterial lumen, which is responsible for the ischemic symptoms of GCA. In this paper, we review recent progress in our understanding of GCA pathogenesis in the fields of genetics, epigenetics, infections, immunology and vascular remodeling.

Communication Is Key: Mechanisms of Intercellular Signaling in Vasodilation.

Thirty years ago, Robert F. Furchgott concluded that nitric oxide, a compound traditionally known to be a toxic component of fuel exhaust, is in fact released from the endothelium, and in a paracrine fashion, induces relaxation of underlying vascular smooth muscle resulting in vasodilation. This discovery has helped pave the way for a more thorough understanding of vascular intercellular and intracellular communication that supports the process of regulating regional perfusion to match the local tissue oxygen demand. Vasoregulation is controlled not only by endothelial release of a diverse class of vasoactive compounds such as nitric oxide, arachidonic acid metabolites, and reactive oxygen species, but also by physical forces on the vascular wall and through electrotonic conduction through gap junctions. Although the endothelium is a critical source of vasoactive compounds, paracrine mediators can also be released from surrounding parenchyma such as perivascular fat, myocardium, and cells in the arterial adventitia to exert either local or remote vasomotor effects. The focus of this review will highlight the various means by which intercellular communication contributes to mechanisms of vasodilation. Paracrine signaling and parenchymal influences will be reviewed as well as regional vessel communication through gap junctions, connexons, and myoendothelial feedback. More recent modes of communication such as vesicular and microRNA signaling will also be discussed.

High fat diet increases salt sensitivity and promotes metabolic disorder‐independent hypertension in Dahl salt sensitive rats

Salt sensitivity of blood pressure is common in obesity associated hypertension and may have a neurogenic basis. We and others have previously reported that high fat (HF) diet promotes hypertension in Dahl salt sensitive (SS) male rats ingesting a “normal” salt diet (0.33% NaCl). It is unclear if a low salt intake would reduce blood pressure in this model of obesity‐associated hypertension. Therefore in the current study Dahl SS rats were fed a normal fat (NF, 10% kcal from fat) and HF (60% kcal from fat) diet with different salt contents for 24–26 weeks after weaning (3 weeks of age). In rats fed a diet containing 0.24–0.33% NaCl (the normal salt content (NS) in rodent diets), HFNS (n=9) rats had a much higher MAP than NFNS rats (n=10) at the end of the study (158±1 mmHg versus 130±1 mmHg, P&lt;0.05), confirming our previous findings. However, in low salt fed rats (LS, 0.1% NaCl), MAP at the end of the study was only slightly higher in HFLS (n=4) than NFLS (n=5) rats (131±1 mmHg vs 121±3 mmHg, P&lt;0.05). Body weight was not significantly greater, but visceral adipose accumulation was higher, in HFNS and HFLS rats compared to NFNS and NFLS fed rats, respectively. HF fed rats did not show significant alterations in plasma levels of fasting glucose, insulin, leptin, aldosterone and serum creatinine compared to NF rats. Only HFNS rats showed hyperlipidemia and only NFLS rats showed lower plasma urea BUN levels than the other groups of rats. HFNS rats had a larger depressor response to ganglion blockade than did NFNS rats, but this was not observed in HFLS rats compared to NFLS animals. HF diet did not affect the mesenteric arterial (MA) contractile responses to neurotransmitters (norepinephrine and ATP), but MA from HFNS rats exhibited significantly increased wall‐thickness (and cardiac hypertrophy) compared to NFNS rats. Morphological studies did not reveal greater fibrosis in adventitia of mesenteric, intrarenal or coronary arteries in HF rats, suggesting arterial hyperplasia accounted for arterial remodeling in HFNS rats. Our studies suggested that obesity‐associated hypertension in Dahl SS rats is salt‐sensitive and neurogenic, but not associated with obvious metabolic disorders.Support or Funding InformationSupported by NIH2P01HL070687‐11A1

Physiopathologie des artérites à cellules géantes

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are two granulomatous vasculitis affecting large arteries. Their exact pathogenesis is not fully understood but major progresses have been done last years, especially in the knowledge of the pathogenesis of GCA, thus providing new therapeutic targets like the inhibition of the interleukin-6 (IL-6) pathway. The trigger of these diseases is not clearly identified but it is thought that an infectious agent could activate and lead to the maturation of dendritic cells that are localized in the adventitia of arteries. Then, CD4 T cells are recruited and polarize into Th1 and Th17 cells that produce IFN-γ and IL-17, respectively. Following IFN-γ secretion, CD8 T cells and monocytes are recruited, monocytes differentiate into macrophages that form giant cells. With the contribution of resident cells, immune cells trigger the destruction and the remodeling of the arterial wall, thus leading to the progressive occlusion of the arterial lumen which is responsible for ischemic symptoms of GCA. In this paper, we review recent progresses in the knowledge of the pathogenesis of GCA with a particular focus on the links with polymyalgia rheumatica.