Qualitative and quantitative characteristics of the passive compartment underneath the myocardial bridge comprising the blood vessel adventitia and the perivascular connective tissue / Características cualitativas y cuantitativas del compartimento pasivo debajo del puente miocárdico que comprende la adventicia del vaso sanguíneo y el tejido conectivo perivascular

SUMMARY: Myocardial bridges are inborn anomalies frequently found in authopsies. Although tipically clinically silent, they are occasionally associated with severe clinical manifestations, e.g. myocardial ischemia or even sudden death. The pathophysiology and risk factors for these manifestations have not yet been completely elucidated. The connective tissue underneath the bridge has been considered as one of the factors the symptoms depend on. Thus, the aim of this research was to determine the histological characteristics of the connective tissue lying underneath the myocardial bridge and to contribute to a better understanding of the protective effects this passive compartment might have in prevention of severe clinical manifestations of myocardial bridging. The study was carried out on twenty hearts with myocardial bridges. Length of the bridge was determined using a precise electronic caliper. Sections of the myocardial bridges with the underlying connective tissue were obtained and prepared for qualitative and quantitative analysis. The connective tissue underneath the bridges was composed of adipose tissue and loose connective tissue in different ratios. The tissue underneath thin bridges was predominantly composed of adipose tissue, while loose connective tissue was the dominant component under thick bridges. The myocardial bridges had an average thickness of 0,98 ± 0.44 mm and an average length of 15,25±5,65 mm. We found a strong positive correlation between the myocardial bridge thickness and length (r = 0,860, p = 0,0001). The thickness of the passive connective tissue compartment under the myocardial bridges was 0,58±0,22 mm, and there was no correlation between this parameter and the myocardial bridge thickness (r = -0,011; p = 0,963). In the clinical evaluation of patients with these anomalies it is necessary to take into account independently the myocardial bridge thickness and length on one side and the thickness of the connective tissue lying underneath it on the other.

Los puentes miocárdicos son anomalías congénitas que se encuentran con frecuencia en las autopsias. Aunque típicamente éstos son clínicamente silenciosos, ocasionalmente se asocian con manifestaciones clínicas graves, como isquemia miocárdica o incluso muerte súbita. La fisiopatología y los factores de riesgo de estas manifestaciones aún no se han dilucidado por completo. El tejido conectivo debajo del puente se ha considerado como uno de los factores de los que dependen los síntomas. Por lo tanto, el objetivo de esta investigación fue determinar las características histológicas del tejido conectivo que se encuentra debajo del puente miocárdico y contribuir a una mejor comprensión de los efectos protectores que este compartimento pasivo podría tener en la prevención de manifestaciones clínicas graves de puente miocárdico. El estudio se llevó a cabo en veinte corazones con puentes miocárdicos. La longitud del puente se determinó utilizando un calibrador electrónico preciso. Se obtuvieron secciones de los puentes miocárdicos con el tejido conjuntivo subyacente y se prepararon para análisis cualitativo y cuantitativo. El tejido conectivo debajo de los puentes estaba compuesto de tejido adiposo y tejido conectivo laxo en diferentes proporciones. El tejido debajo de los puentes delgados estaba predominantemente compuesto de tejido adiposo, mientras que el tejido conectivo laxo era el componente dominante debajo de los puentes gruesos. Los puentes de miocardio tenían un espesor promedio de 0,98 ± 0,44 mm y una longitud promedio de 15,25 ± 5,65 mm. Encontramos una fuerte correlación positiva entre el grosor y la longitud del puente miocárdico (r = 0,860, p = 0,0001). El grosor del compartimiento de tejido conectivo pasivo debajo de los puentes miocárdicos era de 0,58±0,22 mm, y no hubo correlación entre este parámetro y el grosor del puente miocárdico (r = -0,011; p = 0,963). En la evaluación clínica de pacientes con estas anomalías es necesario tener en consideración de forma independiente el grosor y la longitud del puente de miocardio por un lado y el grosor del tejido conectivo que se encuentra debajo del mismo por el otro.

From Uniaxial Testing of Isolated Layers to a Tri-Layered Arterial Wall: A Novel Constitutive Modelling Framework.

Mechanical testing and constitutive modelling of isolated arterial layers yields insight into the individual layers' mechanical properties, but per se fails to recapitulate the in vivo loading state, neglecting layer-specific residual stresses. The aim of this study was to develop a testing/modelling framework that integrates layer-specific uniaxial testing data into a three-layered model of the arterial wall, thereby enabling study of layer-specific mechanics under realistic (patho)physiological conditions. Circumferentially and axially oriented strips of pig thoracic aortas (n = 10) were tested uniaxially. Individual arterial layers were then isolated from the wall, tested, and their mechanical behaviour modelled using a hyperelastic strain energy function. Subsequently, the three layers were computationally assembled into a single flat-walled sample, deformed into a cylindrical vessel, and subjected to physiological tension-inflation. At the in vivo axial stretch of 1.10 ± 0.03, average circumferential wall stress was 75 ± 9 kPa at 100 mmHg, which almost doubled to 138 ± 15 kPa at 160 mmHg. A ~ 200% stiffening of the adventitia over the 60 mmHg pressure increase shifted layer-specific load-bearing from the media (65 ± 10% → 61 ± 14%) to the adventitia (28 ± 9% → 32 ± 14%). Our approach provides valuable insight into the (patho)physiological mechanical roles of individual arterial layers at different loading states, and can be implemented conveniently using simple, inexpensive and widely available uniaxial testing equipment.

Surgical Anatomy of the Rectovaginal Space: Does a Standalone Rectovaginal Septum or Denonvilliers Fascia Exist in Women?

BACKGROUND: Below the anterior peritoneal reflection, the anterior rectal wall and mesorectum are separated from the posterior vaginal wall by a virtual rectovaginal space. In this space, the description of a specific and independent rectovaginal septum as a female counterpart of Denonvilliers fascia has been the subject of debate over the years. OBJECTIVE: The aim of this study is to perform an accurate anatomical study of the rectovaginal area in a cadaveric simulation model of total mesorectal excision to evaluate the possible structures and the dissection planes contained within the rectovaginal space. DESIGN AND SETTING: This is a cadaveric study performed at the University of Valencia. PATIENTS: The pelvises of 25 formalin-preserved female cadavers were dissected. All the included specimens were sectioned in a midsagittal plane, at the level of the middle axis of the anal canal. MAIN OUTCOME MEASURES: Careful and detailed dissection was performed to visualize the anatomical structures and potential dissection planes during anterior mesorectal dissection in cadavers. Histological sections were made of the posterior vaginal wall. RESULTS: The rectovaginal space contains loose areolar tissue that allows an easy dissection plane distally. A distinct and independent rectovaginal fascia or septum is not present. The existence of 3 layers fused together in the posterior vaginal wall can be identified more or less precisely because of their different coloration. The histological study confirms this macroscopic arrangement of the posterior vaginal wall in 3 layers: the mucosa, the muscular, and the adventitia. An independent rectovaginal septum can be generated only with a splitting of the adventitia. LIMITATIONS: The cadaveric pelvic specimens of the oldest donors might have had age-related degeneration. CONCLUSIONS: The present anatomical study has shown only a plane of loose areolar tissue between the rectal and vaginal wall. We can conclude that there is no independent fascia or septum in the rectovaginal space. See Video Abstract at http://links.lww.com/DCR/B456. ANATOMÍA QUIRÚRGICA DEL ESPACIO RECTOVAGINAL: ¿EXISTE UN TABIQUE RECTOVAGINAL INDEPENDIENTE O UNA FASCIA DE DENONVILLIERS EN LAS MUJERES: Debajo del reflejo peritoneal anterior, la pared rectal anterior y el mesorrecto están separados de la pared vaginal posterior por un espacio rectovaginal virtual. En este espacio, la descripción de un tabique rectovaginal independiente específico como contraparte femenina de la fascia de Denonvilliers ha sido objeto de debate a lo largo de los años.Realizar un estudio anatómico preciso del área rectovaginal en un modelo de simulación cadavérica de escisión mesorrectal total, con el fin de evaluar las posibles estructuras y los planos de disección contenidos en el espacio rectovaginal.estudio cadavérico realizado en la Universidad de Valencia.Se disecaron las pelvis de 25 cadáveres femeninos conservados en formalina. Todas las muestras incluidas fueron seccionadas en un plano medio sagital, a la altura del eje medio del canal anal.Se llevó a cabo una disección cuidadosa y detallada para visualizar las estructuras anatómicas y los posibles planos de disección durante la disección mesorrectal anterior en cadáveres. Se realizaron cortes histológicos de la pared vaginal posterior.El espacio rectovaginal contiene tejido areolar laxo que permite un plano de disección fácil distalmente. No hay fascia o tabique rectovaginal distinto e independiente. La existencia de tres capas fusionadas en la pared vaginal posterior puede identificarse con mayor o menor precisión debido a su diferente coloración. El estudio histológico confirma esta disposición macroscópica de la pared vaginal posterior en tres capas: la mucosa, la muscular y la adventicia. Un tabique rectovaginal independiente solo se puede generar con una división de la adventicia.Las muestras pélvicas de cadáveres de los donantes más antiguos pueden haber tenido degeneración relacionada con la edad.El estudio anatómico actual solo ha mostrado un plano de tejido areolar laxo entre la pared rectal y vaginal. Podemos concluir que no hay fascia o tabique independiente en el espacio rectovaginal. Consulte Video Resumen en http://links.lww.com/DCR/B456. (Traducción-Dr. Adrian Ortega).

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.

Regional distribution of layer-specific circumferential residual deformations and opening angles in the porcine aorta.

Information on the layer-specific residual deformations of aortic tissue and how these vary throughout the vessel is important for understanding the regionally-varying aortic functions and pathophysiology, but not so much can be found in the literature. Toward this end, porcine aortas were sectioned into eighteen rings, with one ring from each anatomical position radially cut to obtain the zero-stress state for the intact wall and the other ring dissected into intimal-medial and adventitial layers; these rings were then radially cut to reach the zero-stress state for the intima-media and adventitia. Peripheral variations in internal/external circumferences, thickness, and opening angle of the intact wall and its layers were measured through image analysis at the no-load and zero-stress states. Intact wall and layer circumferences at both states significantly declined along the aorta, as did intact wall and intimal-medial but not adventitial thickness. Adventitia exhibited the greatest opening angles, approaching 180 deg all over the aorta. The opening angles of the intima-media and intact wall were quite similar, with the highest values in the ascending aorta, the lowest at the diaphragm, and increasing subsequently. Bending-related residual stretches were released by radial cutting that were compressive internally and tensile externally, displaying distinct axial variation for the intima-media and intact wall, and non-significant variation for the adventitia. Evidence is provided for the release upon layer separation of compressive stretches in the intima-media and of tensile stretches in the adventitia, whose values were smallest in the descending thoracic aorta and highest near the iliac artery bifurcation.

Layer-specific arterial micromechanics and microstructure: Influences of age, anatomical location, and processing technique.

The importance of matrix micromechanics is increasingly recognized in cardiovascular research due to the intimate role they play in local vascular cell physiology. However, variations in micromechanics among arterial layers (i.e. intima, media, adventitia), as well as dependency on local matrix composition and/or structure, anatomical location or developmental stage remain largely unknown. This study determined layer-specific stiffness in elastic arteries, including the main pulmonary artery, ascending aorta, and carotid artery using atomic force indentation. To compare stiffness with age and frozen processing techniques, neonatal and adult pulmonary arteries were tested, while fresh (vibratomed) and frozen (cryotomed) tissues were tested from the adult aorta. Results revealed that the mean compressive modulus varied among the intima, sub-luminal media, inner-middle media, and adventitia layers in the range of 1-10 kPa for adult arteries. Adult samples, when compared to neonatal pulmonary arteries, exhibited increased stiffness in all layers except adventitia. Compared to freshly isolated samples, frozen preparation yielded small stiffness increases in each layer to varied degrees, thus inaccurately representing physiological stiffness. To interpret micromechanics measurements, composition and structure analyses of structural matrix proteins were conducted with histology and multiphoton imaging modalities including second harmonic generation and two-photon fluorescence. Composition analysis of matrix protein area density demonstrated that decrease in the elastin-to-collagen and/or glycosaminoglycan-to-collagen ratios corresponded to stiffness increases in identical layers among different types of arteries. However, composition analysis was insufficient to interpret stiffness variations between layers which had dissimilar microstructure. Detailed microstructure analyses may contribute to more complete understanding of arterial micromechanics.

Hydrogen peroxide and nitric oxide induce anticontractile effect of perivascular adipose tissue via renin angiotensin system activation.

The perivascular adipose tissue (PVAT) is located around the adventitia, composed primarily by adipocytes, stromal cells, leukocytes, fibroblasts and capillaries. It is well described that PVAT is an important modulator of the vascular tone being considered a biologically active tissue, releasing both vasoconstrictor and vasodilators factors. The literature shows that the anti-contractile effect induced by PVAT may be due to activation of the renin-angiotensin system (RAS). AIM: Investigate whether the renin-angiotensin system participates in the effect exerted by perivascular adipose tissue on the vascular tone. METHODS AND RESULTS: For this study we used thoracic aorta from Balb/c mice and performed vascular reactivity, nitric oxide and hydrogen peroxide quantification using selective probes and fluorescence microscopy, immunofluorescence to locate receptors and enzymes involved in this response. Our results demonstrated that perivascular adipose tissue induces an anti-contractile effect in endothelium-independent manner and involves Mas and AT2 receptors participation with subsequent PI3K/Akt pathway activation. This pathway culminated with nitric oxide and hydrogen peroxide production by neuronal nitric oxide synthase, being hydrogen peroxide most relevant for the anti-contractile effect of perivascular adipose tissue. CONCLUSION: For the first time in the literature, our results show the presence of Mas and AT2 receptors, as well as, nitric oxide synthase on perivascular adipose tissue. Furthermore, our results show the involvement of Mas and AT2 receptors and consequently nitric oxide synthase activation in the anti-contractile effect exerted by perivascular adipose tissue.

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.

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.

How many Layers has the Adventitia? - Structure of the Arterial Tunica Externa Revisited.

Tunica adventitia or tunica externa is the outer layer of the blood vessel wall. It consists of connective tissue with vasa and nervi vasorum and plays a key role in vascular health. The aim of our study was to compare the wall layers beyond tunica media in arteries of different type and location. The following arteries of pig, dog and cat were processed histologically and analysed by light microscopy: aorta ascendens, arcus aortae, aorta thoracica, aorta abdominalis, arteria (a.) femoralis, a. tibialis cranialis, a. carotis communis, a. lingualis, a. basilaris, a. cerebralis media, a. testicularis and aa. jejunales. We found two layers of connective tissue outside the media: (1) a compact layer with many elastic fibres in muscular and few in elastic arteries and (2) an outer layer of loose connective tissue. The compact layer was missing in aorta ascendens, arcus aortae and intracranial vessels. Adventitial stripping removed only the loose connective tissue layer. In spite of the still present compact layer, stripped arteries were very flimsy. We suggest using the term 'tunica externa' for the compact connective tissue layer and 'tunica adventitia' for the outermost loose connective tissue layer as in other organs. The presence of the tunica externa differs between species, arteries and arterial side, as well as the removability of tunica adventitia and tunica externa by anatomical dissection.

Topologic distributions of vasa vasorum and lymphatic vasa vasorum in the aortic adventitia--Implications for the prevalence of aortic diseases.

BACKGROUND AND AIMS: Vasa vasorum (VV) and lymphatic vasa vasorum (LVV) form their own networks in the adventitia. VV supply the aorta with nutrition and oxygen; however, the distribution and role of LVV remains to be determined. The purpose of this study was to investigate differences in the distribution of VV and LVV along the aorta. METHODS: Aortic samples were obtained from 22 autopsy cases without medical history of aortic diseases. Aortic segments were classified as arch (Ar), descending thoracic (De), suprarenal abdominal (S-Ab), and infrarenal abdominal (I-Ab). Adventitial VV and LVV were identified immunohistochemically. RESULTS: VV were most dense in the arch aorta, becoming less dense along the aorta in more distal segments, with the lowest density occurring in the infrarenal abdominal aorta. There was a significant correlation between the numbers of VV and medial thickness in the total aortic segments (r = 0.518, p < 0.01). In contrast, there was no significant correlation between the number of LVV and medial thickness in any aortic segments. However, there was a significant correlation between the number of LVV and intimal thickness in I-Ab (r = 0.425, p < 0.05). CONCLUSIONS: The distributions of adventitial VV and LVV were characteristic along the aortic segments. Differences in the distributions may imply the prevalence of aortic diseases such as dissection, abdominal aortic aneurysm, and atherosclerotic occlusive disease in each aortic segment.

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.

Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography.

Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons.

Identification and characterisation of regional variations in the material properties of ureter according to microstructure.

There are few previous studies on the elastic properties of ureter and most have been limited to essentially one-dimensional deformation measurements. The object of this study was, therefore, to identify regional variations in the multiaxial behaviour of rabbit ureter, subjected to in vitro inflation/extension testing under a physiological range of intraluminal pressures and longitudinal forces. A microstructure-motivated material model (via two- and four-fibre families in turn for elastin and collagen) was implemented and its capacity to mathematically characterise the experimental data contrasted favourably with that of the well-established phenomenological models, but it was compromised by parameter covariance. Extensive optimisation studies confirmed that the reduced model without contribution to the elastin and circumferential-fibre (collagen) families characterised the data equally well without over-parameterisation. In view of the fitted parameters, the ureteral tissue was stiffer longitudinally, justified by the preferential alignment of collagen along that axis and the lower ureter was stiffer than the upper ureter, justified by the histological observation of a thickest lamina propria, i.e. of highest collagen content, there. The lower ureter was less anisotropic than the upper ureter, possessing a comparatively larger amount of diagonally arranged collagen fibres in tunica mucosa, while having the usual amounts of longitudinally arranged fibres in tunica adventitia and of circumferentially arranged fibres in tunica muscularis. The present data may be used as inputs to mathematical models of the ureter, assessing regional and intramural stress distributions, through which it is hoped that an improved appreciation of ureteral function may be attained in both health and disease.

Genetic epidemiology and genome-wide linkage analysis of carotid artery ultrasound traits in multigenerational African ancestry families.

OBJECTIVE: Intima-media thickness, adventitial diameter and lumen diameter are indicators of cardiovascular disease risk. The influence of genetic factors on these measures in African ancestry populations is not well defined. Therefore, we estimated heritability and performed genome-wide linkage analysis of carotid ultrasound traits in 7 multigenerational families of African ancestry. METHODS: A total of 395 individuals (7 pedigrees; mean family size = 56; 2392 relative pairs) aged ≥18 years had a common carotid artery ultrasound scan. Statistical analyses were conducted using pedigree-based maximum likelihood methods. RESULTS: Significant covariates included age, sex, body mass index or height and waist, and systolic blood pressure. Residual heritabilities ranged from 0.35 ± 0.10 to 0.64 ± 0.12 (P < 0.0001). We identified a novel quantitative trait locus for adventitial and lumen diameters on chromosome 11 (max LOD = 4.09, 133 cm). CONCLUSION: Further fine mapping of this region may identify specific mutations predisposing to subclinical vascular disease among African ancestry individuals.

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.

Aquaporin water channels in the canine gubernaculum testis.

The jelly-like gubernaculum testis (GT) is a hydrated structure consisting of a concentric sheath of dense connective tissue around a loose mesenchymal core, with two cords of skeletal muscle cells asymmetrically placed alongside. Expansion of the GT occurs during the transabdominal phase of testicular descent, linked to cell proliferation together with modifications of the hydric content of the organ. The aim of this study was to detect immunohistochemically the presence of aquaporins (AQPs), integral membrane proteins permitting passive transcellular water movement, in the canine GTs. Samples (n=15) were obtained from pregnancies of 9 medium sized bitches and dissected from healthy fetuses. Five fetuses were aged 35-45 days of gestation, 10 fetuses from 46 days of gestation to delivery, thus offering us the opportunity to study the progressive maturation of the gubernacula. The presence of AQP3, 4, 7, 8 and -9 was assessed in the muscular components of the GT, some of them (AQP3, AQP4, AQP7) with increasing intensity through the second half of pregnancy up to term. AQP1 was localized in the capillary and venous endothelia in the younger fetuses, also in the artery adventitia and in the nerve perineurium in progressively older fetuses. These data demonstrate the potential importance and contribution of AQP-mediated water flux in hydration and volume modification of the growing GT in a canine model.

Assessment of pulmonary artery morphology by optical coherence tomography.

Since its invention, optical coherence tomography (OCT) has been primarily used for the diagnosis of coronary artery disease. A few feasibility studies of OCT to visualise the pulmonary arteries were reported. However, OCT findings in the pulmonary arteries have not been validated using histology as the gold standard. To validate OCT findings for pulmonary arterial imaging, we selected 27 pulmonary arteries from 11 cadavers (6 males, 5 females, mean age 39.6 ± 21.3 years). Comparison of OCT images and histology was performed. Each histological sample was examined using three types of stains, and the quantified results were analysed by statistics. In conclusion, there was a strong correlation between histology and OCT measurements of the pulmonary arterial wall thickness, the pulmonary arterial wall has a single-layered structure with an average thickness of 0.162 mm. We propose that OCT is probably a useful tool of diagnosing pulmonary artery hypertension and may provide a means to study the pulmonary remodelling process.

The contribution of vascular smooth muscle, elastin and collagen on the passive mechanics of porcine carotid arteries.

The main components responsible for the mechanical behavior of the arterial wall are collagen, elastin, and smooth muscle cells (SMCs) in the medial layer. We determined the structural and mechanical changes in porcine carotid arteries after administration of Triton® X-100, elastase, and collagenase using the inflation-deflation test. The arteries were intraluminarly pressurized from 0 to 200 mmHg, and the outer diameter of the artery was measured. The pressure-strain elastic modulus was determined based on the pressure/diameter ratio. The intima-media thickness, wall thickness, thickness of the tunica adventitia layer, and the area fractions of SMCs, elastin, and collagen within the arterial wall (A(A)(SMC/elastin/collagen, wall)) were measured using stereological methods. The relative changes in the relevant components of the treated samples were as follows: the decrease in A(A)(SMC, wall) after administration of Triton® X-100 was 11% ± 7%, the decrease in A(A)(elastin, wall) after administration of elastase was 40% ± 22%, and the decrease in A(A)(collagen, wall) after the application of collagenase was 51% ± 22%. The Triton® X-100 treatment led to a decrease in the SMC content that was associated with enlargement of the arterial wall (outer diameter) for pressures up to 120 mmHg, and with mechanical stiffening of the arterial wall at higher pressures. Elastase led to a decrease in the elastin content that was associated with enlargement of the arterial wall, but not with stiffening or softening. Collagenase led to a decrease in collagen content that was associated with a change in the stiffness of the arterial wall, although the exact contribution of mechanical loading and the duration of treatment (enlargement) could not be quantified.