Growth-related micromorphological characteristics of the porcine common carotid artery.

The purpose of this study was to gain knowledge about the micromorphology of the porcine common carotid artery (CCA) during the period of growth over the bodyweight range of 10-40 kg. CCA samples from German landrace pigs (DL) aged either 2 or 3 months (DL-2 and DL-3) were compared with samples from Göttingen minipigs (GM) aged either 18 or 40 months (GM-18 and GM-40) using transmitted light (phase-contrast mode) and transmission electron microscopy. The GM-18, GM-40 and the DL-3 groups had typical muscular artery histological characteristics. Contrasting to this, the 2-month-old DL pigs had a transitional artery type being characterized by a significantly higher proportion of elastic fibres and a significantly lower number of smooth muscle cells than did the 1 month older DL-3. During the period of maturation, the tunica media of the CCA in GM animals thickened by 1.3× and in DL animals by 2.5× resulting in an overall increased vessel wall thickness. The cumulated thickness of the tunica interna (endothelium, stratum subendotheliale and internal elastic lamina) and the tunica media (including the external elastic lamina) of DL-3 and GM-40 pigs were similar to each other and comparable to that of humans. With an increasing vessel wall thickness, the luminal diameter decreased in GM by 19% and in DL by 11%. Additionally, in the older age groups, GM-40 and DL-3, the internal elastic lamina principally was continuous, but there were also interrupted large segments of elastic lamina separated by gaps. In addition, the principal internal elastic lamina was duplicated in several places.

Some segmental morphological and morphometrical features of the intima and media of the aortic wall in Chinchilla lanigera.

BACKGROUND: The aim of this study is to describe the morphology, morphometry and ultrastructure of segments of the thoracic and abdominal aorta portions in Chinchilla lanigera. Thickness measurements of the tunica intima and media complex of the aorta were taken. MATERIALS AND METHODS: In all observed specimens, the thickness values for the tunica intima and media complex of the cranial thoracic aorta were significantly higher (mean: 702.19 µm) when compared to the values of other analysed aortic segments (means: 354.18 µm; 243.55 µm). Complex statistical methods were used to assess the differences between various aortic segments. RESULTS AND CONCLUSIONS: The components of the vessel walls show variations in structure and thickness, presumably due to an adaptation to functional demand.

Adiposity and Physical Activity Do Not Mediate the Longitudinal Association Between Sleep Quality and Arterial Thickness Among Adolescents.

STUDY OBJECTIVES: Sleep is a behavior with the potential to affect cardiovascular health. Given the fact that adiposity and physical activity seem to be related to cardiovascular risk factors during growth, it is still unclear whether sleep quality could affect arterial thickness among adolescents. Thus, the objective of the current study was to analyze the effect of sleep quality on arterial thickness and identify the possible mediation role of physical activity and trunk fat in adolescents. METHODS: This was a longitudinal study (12-month follow-up) composed of 71 adolescents with ages ranging from 11 to 14 years at baseline (absence of any known chronic diseases, and no regular medicine use). All variables were assessed twice (baseline and 12-month follow-up): (1) sleep quality was reported using the Mini Sleep Questionnaire (MSQ); (2) physical activity was estimated using pedometers; (3) trunk fat was assessed using a densitometry scanner; and (4) carotid intima-media thickness (CIMT) and femoral intima-media thickness (FIMT) were assessed using ultrasonography. RESULTS: Adolescents who presented poor sleep quality demonstrated significantly increased FIMT (r = .299, 95% confidence interval .071 to .498) and for every point increase in the MSQ score from baseline to follow-up there was a 1.12% (95% confidence interval 0.26 to 1.98) increase in FIMT over time. Moreover, trunk fat and physical activity did not mediate the association between sleep quality and arterial thickness, but FIMT had a positive and independent relationship only with trunk fat. CONCLUSIONS: Sleep quality was positively associated with FIMT among adolescents, whereas physical activity and adiposity did not mediate this process.

Quantitative analysis of the elastic fiber in the tunica media at the carotid bifurcation.

In this study, the results of our previously reported technique of quantitative analysis by using microscopic image analysis of tissue image slices to calculate the proportion of the area of the tunica media occupied by of elastic fibers was compared with Janzen et al.'s technique at the carotid bifurcation. This particularly analyzed the area of transition between the common carotid and the internal carotid, to observe the quantitative changes in elastic fiber content. The data obtained from our quantitative analysis of elastic fibers were clearly at variance with those obtained by counting the number of elastic fibers. The amount of elastic fibers in the tunica media (the elastic fiber ratio) decreased from the proximal carotid artery (the common carotid) to the bifurcation, then peaked in the internal carotid immediately after the bifurcation before declining again.

Structural modeling reveals microstructure-strength relationship for human ascending thoracic aorta.

High lethality of aortic dissection necessitates accurate predictive metrics for dissection risk assessment. The not infrequent incidence of dissection at aortic diameters <5.5 cm, the current threshold guideline for surgical intervention (Nishimura et al., 2014), indicates an unmet need for improved evidence-based risk stratification metrics. Meeting this need requires a fundamental understanding of the structural mechanisms responsible for dissection evolution within the vessel wall. We present a structural model of the repeating lamellar structure of the aortic media comprised of elastic lamellae and collagen fiber networks, the primary load-bearing components of the vessel wall. This model was used to assess the role of these structural features in determining in-plane tissue strength, which governs dissection initiation from an intimal tear. Ascending aortic tissue specimens from three clinically-relevant patient populations were considered: non-aneurysmal aorta from patients with morphologically normal tricuspid aortic valve (CTRL), aneurysmal aorta from patients with tricuspid aortic valve (TAV), and aneurysmal aorta from patients with bicuspid aortic valve (BAV). Multiphoton imaging derived collagen fiber organization for each patient cohort was explicitly incorporated in our model. Model parameters were calibrated using experimentally-measured uniaxial tensile strength data in the circumferential direction for each cohort, while the model was validated by contrasting simulated tissue strength against experimentally-measured strength in the longitudinal direction. Orientation distribution, controlling the fraction of loaded collagen fibers at a given stretch, was identified as a key feature governing anisotropic tissue strength for all patient cohorts.

Histological characterization of umbilical cord in alpaca (Vicugna pacos).

The histomorphometric features of umbilical cord constituents in seven foetuses of alpaca (Vicugna pacos) from Cerro de Pasco, Department, Peru, were determined. Sections of 2-5 cm of umbilical cord were fixed in 10% neutral buffered formalin and processed for light microscopy. Standard histological slides stained with haematoxylin and eosin, Masson's trichrome and Van Gieson's trichrome were obtained. Histologically, common features of umbilical artery and vein were observed as well as mucous connective tissue, some cell features that compound this tissue constituted by cells presented features of myofibroblasts. Among most important findings that were observed, the lumen of umbilical vein was obliterated into star-shaped form with the thinner umbilical artery wall; the smooth muscles and fibroblast were comparatively more in number in umbilical artery than that of umbilical vein, and the tunica media was larger in dimension than the tunica adventitia in umbilical vein. Conclusively, this histological study features an observation of the umbilical cord of alpaca foetuses and shows the similarity between them and those of other mammal species, including dromedaries and South American camelids.

Morphometric changes in the aortic arch with advancing age in fetal to mature thoroughbred horses.

Aortic rupture is a well recognized cause of sudden death in thoroughbred horses. Some microscopic lesions, such as those caused by cystic medial necrosis and medionecrosis, can lead to aortic rupture. However, these microscopic lesions are also observed in normal horses. On the other hand, a previous study of aortic rupture suggested that underlying elastin and collagen deposition disorders might be associated with aortic rupture. Therefore, the purpose of this study was to compare the structural components of the tunica media of the aortic arch, which is composed of elastin, collagen, smooth muscle cells and mucopolysaccharides (MPS), in fetal to mature thoroughbred horses. The percentage area of elastin was greatest in the young horses and subsequently decreased with aging. The percentage area of collagen increased with aging, and the elderly horses (aged ≥20) exhibited significantly higher percentage areas of collagen than the young horses. The percentage area of smooth muscle cells did not change with age. The percentage area of MPS was inversely proportional to the percentage area of elastin. The fetuses exhibited a markedly larger percentage area of MPS than the mature horses. We concluded that the medial changes seen in the aortic arch, which included a reduction in the amount of elastin and increases in the amounts of collagen and MPS, were age-related variations.

Morphological Studies on the Peripheral Circulation of the Ovary in One-Humped Camel (Camelus dromedarius).

Histological examination of the peripheral circulation of the ovary of 18 females of the one-humped camel revealed a series of blood vessels with special structures. Throttle or occlusive artery was recorded in the ovarian zona vasculosa and in the cortex, and it showed an intimal cushion-like thickening made up of intimal bolsters that formed of smooth muscle fibres and glomus cells. The smooth muscle cells of the tunica media and the tunica adventitia of throttle artery pursued a circumferential pattern. Anastomosis arteriovenosa included simple bridge-like anastomotic vessels between arteria and venae, and glomus vessels of typical structure were demonstrated. Glomus organs were recorded in the ovary and were comprised of the tortuous glomus vessels and the related afferent and efferent vessels. Glomus cell complexes also were commonly occur at the cortex ovarii that possessed an extremely convoluted course with a hyperplastic wall and a narrow lumen. Atypical glomus vessels were demonstrated within the ovarian zona vasculosa, and the wall of these vessels was relatively thick and consisted of double tunica media with an intimal bolster. Some vessels contained an intimal bolster device of exclusively glomus cell structure (glomus bolster) with a tunica elastic interna demarcated it from the glomus cell media. Some venae represented several layers of longitudinally arranged smooth muscle fibres in the tunica media. Other venae showed wall with variable thickness. Venae with double muscular tunica media were recorded in the medulla. Some venae showed double internal elastic lamina. Also, venae with thick adventitia contained dispersed smooth muscle fibres were determined. Spirally oriented arteriole and venule were demonstrated within the cortex and medulla ovarii. Gestation sclerosis was demonstrated in ovarian zona vasculosa of pregnant females.

Aortic intima-media thickness measured by trans-abdominal ultrasound as an early life marker of subclinical atherosclerosis.

UNLABELLED: Atherosclerosis is a chronic inflammatory process that begins in early life. Improved identification of markers of early atherosclerosis via neonatal aortic intima-media thickness (aIMT) measurement may allow the development of interventions to prevent or reduce later cardiovascular disease. CONCLUSION: Using aIMT, studies have shown that antenatal factors such as intra-uterine growth retardation, prematurity, maternal factors and inflammation are associated with early cardiovascular changes.

Structure and immunohistochemistry of the human lenticulostriate arteries.

BACKGROUND: Data about the structure and immunohistochemistry of the lenticulostriate arteries (LSAs), although very important for medical research and clinical practice, have been rarely reported in literature. MATERIALS AND METHODS: Fourty serially sectioned LSAs were stained with hematoxilin and eosin, and prepared for immunohistochemistry. RESULTS: Our examination revealed a typical endothelial lining and a narrow subendothelial space with subintimal smooth muscle cells occasionally. The internal elastic lamina was fragmented or absent in the smallest LSAs branches. The mediacoat, with a mean diameter of 148.5 µm, contained typical smooth muscle cells which formed 14.2 layers on average and showed a positive immune reactions for alfa-actin, desmine, laminin and collagen IV. The thin adventitial coat contained fibroblasts, collagen fibers, and nerve bundles, with the strongest immunopositivity to thyrosin hydroxilase. The immune reactions against CD31 and CD34 proteins,endothelial nitric oxide synthase, S 100 protein, neurofilament protein and synaptophysin,seem to be performed in the LSAs wall for the first time. Similarly,the thickness of the LSAs wall and its coats have never been reported, nor the number of the smooth muscle cell layers. CONCLUSIONS: Our results related to the structure and immunohistochemistry of the LSAs could be important in cerebrovascular pathology, neurology and neurosurgery.

Metabolic and cardiovascular adjustments during psychological stress and carotid artery intima-media thickness in youth.

OBJECTIVE: Cardiovascular reactivity is associated with carotid artery intima-media thickness as early as childhood. Excess cardiovascular responses relative to the metabolic demand during psychological stress have been proposed as a mechanism for this association. However, it is not known whether excess cardiovascular responses in relation to the metabolic demand correlate with carotid artery intima-media thickness as strongly as traditionally measured cardiovascular reactivity. METHODS: Fifty-four adolescents, ages 13-16 years completed a graded exercise test in 1 day and measures of psychological stress reactivity (star tracing, speech) on another day. Heart rate, systolic blood pressure, and oxygen consumption were measured on both days. On a third visit adolescents completed an ultrasound scan to measure carotid artery intima-media thickness. RESULTS: Traditionally measured systolic blood pressure reactivity (ß=0.30, p=0.02, R(2) increase=0.09) and excess systolic blood pressure (ß=0.30, p=0.02, R(2) increase=0.08) while preparing a speech were associated with greater carotid artery intima-media thickness when controlling for demographic characteristics, fitness, and baseline systolic blood pressure. CONCLUSIONS: This study adds to the growing body of literature showing a link between systolic blood pressure reactivity to acute psychological stress and carotid artery intima-media thickness in youth. This was the first study to demonstrate that systolic blood pressure in excess of the metabolic demand during psychological stress was also associated with carotid artery-intima media thickness.

The dynamic structure of arterioles.

Arterioles are the blood vessels in the arterial side of the vascular tree that are located proximal to the capillaries and, in conjunction with the terminal arteries, provide the majority of resistance to blood flow. Consequently, arterioles are important contributors to the regulation of mean arterial pressure and tissue perfusion. Their wall consists of cellular and extracellular components that have been traditionally classified as conforming three layers: an intima containing endothelial cells sited on a basement membrane; a media made of an internal elastic lamina apposed by one or two layers of smooth muscle; and an adventitia composed mostly of collagen bundles, nerve endings and some fibroblasts. These components of the arteriolar wall are dynamically interconnected, providing a level of plasticity to the arteriolar wall that blurs the traditional boundaries of a rigid layered classification. This MiniReview focuses on the structural conformation of the arteriolar wall and shows how wall components interact spatially, functionally and temporally to control vascular diameter, regulate blood flow and maintain vascular permeability.

Comparative regional morphometric changes in human uterine artery before and during pregnancy.

INTRODUCTION: Uterine artery undergoes structural modifications at different physiologic states. It is expected that due to its unique course, hemodynamic stresses in the vessel would vary resulting in differences in arterial dimensions. The objective of this study was to investigate regional morphometric changes in the human uterine artery. METHODS: Twenty four uterine arteries (12 each from non-gravid uteri and gravid uteri) were obtained during autopsy after ethical approval from women aged between 21 to 47 years. Sections from proximal, middle and distal segments of the artery taken within 72 hours were processed for paraffin embedding, sectioned and stained with Mason's Trichrome. Micrographs of the slides were analyzed using Scion Image Multiscan software. Data were entered into and analyzed with Statistical Programme for Social Sciences. RESULTS: The pregnancy related increase in diameter and wall thickness are most pronounced in the proximal segment. In the distal segment, however, wall thickness reduces significantly (p < 0.05). Intimal thickness was lesser in pregnancy compared to non-gravid state in all the segments. CONCLUSION: Regional morphometric changes in the uterine artery during pregnancy may be designed to regulate blood flow to the uterus and placenta during pregnancy.

Association of menopause and hormone replacement therapy with large artery remodeling.

OBJECTIVE: To evaluate the remodeling of large arteries according to age at menopause, duration of menopause, and use of hormone therapy (HT). DESIGN: A cross-sectional study consisting of baseline measurements of a multicentric randomized trial were used to evaluate arterial parameters. SETTING: The study was conducted in France, Belgium, and the Netherlands in academic hospitals and private clinics. PATIENT(S): Postmenopausal women (n = 538) with mild hypercholesterolemia. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Common carotid artery intima-media thickness (CCA-IMT), central pulse pressure, and aortic stiffness (carotid-femoral pulse wave velocity) were measured and centrally controlled for quality. Multivariate regression analysis was used to assess the possible covariates associated with arterial parameters. RESULT(S): Women were 58 ± 6 (mean ± SD) years of age with an age of 50 ± 5 at menopause and a mean duration of menopause of 8 ± 7 years. Lower age at menopause, time since menopause, and absence of HT use were independently associated with worsening of the arterial parameters. After multivariate analysis, HT was associated with a lower CCA-IMT (-40 µm [range -64 to -1]), whereas lower age at menopause and menopause duration were respectively associated with a CCA-IMT increase (25 µm/5 y and 27 µm/5 y). Similarly, values of central pulse pressure and pulse wave velocity were lower in HT users (-3.1 mm Hg [-5.1 to -0.9] and -0.31 m/s [-0.63 to -0.02], respectively) but worsened with age at menopause and menopause duration. CONCLUSION(S): The age at menopause, the time since menopause, and the use of HT are independently associated with the thickening and stiffening of the large arteries. CLINICAL TRIAL REGISTRATION NUMBER: NCT00163163.

Carotid-wall intima-media thickness and cardiovascular events.

BACKGROUND: Intima-media thickness of the walls of the common carotid artery and internal carotid artery may add to the Framingham risk score for predicting cardiovascular events. METHODS: We measured the mean intima-media thickness of the common carotid artery and the maximum intima-media thickness of the internal carotid artery in 2965 members of the Framingham Offspring Study cohort. Cardiovascular-disease outcomes were evaluated for an average follow-up of 7.2 years. Multivariable Cox proportional-hazards models were generated for intima-media thickness and risk factors. We evaluated the reclassification of cardiovascular disease on the basis of the 8-year Framingham risk score category (low, intermediate, or high) after adding intima-media thickness values. RESULTS: A total of 296 participants had a cardiovascular event. The risk factors of the Framingham risk score predicted these events, with a C statistic of 0.748 (95% confidence interval [CI], 0.719 to 0.776). The adjusted hazard ratio for cardiovascular disease with a 1-SD increase in the mean intima-media thickness of the common carotid artery was 1.13 (95% CI, 1.02 to 1.24), with a nonsignificant change in the C statistic of 0.003 (95% CI, 0.000 to 0.007); the corresponding hazard ratio for the maximum intima-media thickness of the internal carotid artery was 1.21 (95% CI, 1.13 to 1.29), with a modest increase in the C statistic of 0.009 (95% CI, 0.003 to 0.016). The net reclassification index increased significantly after addition of intima-media thickness of the internal carotid artery (7.6%, P<0.001) but not intima-media thickness of the common carotid artery (0.0%, P=0.99). With the presence of plaque, defined as intima-media thickness of the internal carotid artery of more than 1.5 mm, the net reclassification index was 7.3% (P=0.01), with an increase in the C statistic of 0.014 (95% CI, 0.003 to 0.025). CONCLUSIONS: The maximum internal and mean common carotid-artery intima-media thicknesses both predict cardiovascular outcomes, but only the maximum intima-media thickness of (and presence of plaque in) the internal carotid artery significantly (albeit modestly) improves the classification of risk of cardiovascular disease in the Framingham Offspring Study cohort. (Funded by the National Heart, Lung, and Blood Institute.).

Histomorphometric and sympathetic innervation of the human internal thoracic artery.

INTRODUCTION: Internal thoracic artery (ITA) is an established arterial graft for the coronary artery by-pass surgery. Special micro-anatomical features of the ITA wall may protect it from age related pathological changes. One of the complications seen after coronary artery bypass grafting is vasospasm. Sympathetic nerves may be involved in vasospasm. OBJECTIVE: To ascertain the sympathetic innervation of the internal thoracic artery and to assess the effect of aging on this artery by histomorphometry. METHOD: Fifty-four human internal thoracic artery samples were collected from 27 cadavers (19 male and 8 female) with ages of 19 to 83 years. Samples were divided into three age groups: G1, 19-40 years; G2, 41-60 years; G3, >61 years. Sections (thickness 5 mm) of each sample were taken and stained with hematoxylin-eosin and Verhoeff-Van Gieson stains. Five of fifty-four samples were processed for tyrosine hydroxylase immunostaining. RESULTS: The thickness of the tunica intima was found to be constant in all age groups, whereas the thickness of the tunica media decreased in proportion to age. Verhoeff-Van Gieson staining showed numerous elastic laminae in the tunica media. Significant differences (p < 0.0001) in the number of elastic laminae were found between G1 with G2 cadavers, between G2 and G3 cadavers and between G3 and G1 cadavers. Tyrosine hydroxylase immunostaining demonstrated sympathetic fibers, located mainly in the tunica adventitia and the adventitia-media border. The sympathetic nerve fiber area and sympathetic index were found to be 0.0016 mm² and 0.012, respectively. DISCUSSION: Histology of the ITA showed features of the elastic artery. This may be associated with lower incidence of Atherosclerosis or intimal hyperplasia in ITA samples even in elderly cases. Low sympathetic index (0.012) of ITA may be associated with fewer incidences of sympathetic nervous systems problems (vasospasm) of the ITA. CONCLUSION: Sympathetic nerve fibers are present in the adventitia of the internal thoracic artery. This is an elastic artery, although anatomically it is considered to be medium-sized. The sympathetic index may be used for analysis of sympathetic nerve fiber-related problems of the internal thoracic artery.

Paraoxonase-1 and oxidative status in common Mediterranean ß-thalassaemia mutations trait, and their relations to atherosclerosis.

AIMS: Investigation of paraoxonase-1 (PON1) activity with oxidative status parameters and the increased susceptibility to atherogenesis in ß-thalassaemia-trait (BTT) subjects. METHODS: Sixty BTT subjects and 20 age- and sex-matched healthy controls were enrolled in the study. Serum PON1, total antioxidant capacity (TAC), malondialdehyde (MDA) and carotid artery intima-media thickness (CIMT) were determined. Qualitative detection of ß-thalassaemia mutations was carried out. RESULTS: Serum PON1 activity and TAC were significantly lower in BTT subjects than in controls (p<0.001), while MDA and CIMT were significantly higher (p<0.001). In BTT subjects, TAC, MDA, and CIMT levels were significantly correlated with serum PON1 (r=0.945, -0.900, 0.940 and -0.922 respectively). Serum TAC and MDA were significantly correlated (r=-0.979). CONCLUSIONS: Oxidative stress is increased, while serum PON1 activity is decreased in BTT subjects. Decrease in PON1 activity is associated with the degree of oxidative stress, anaemia and increase in CIMT. Therefore, BTT subjects may be more prone to development of atherosclerosis.