Human Superficial Temporal Artery Research Articles

Abstract TMP16: Mechanoreceptor Dysregulation Found In Human Intracerebral Aneurysms

Introduction: About 500,000 people worldwide die annually from ruptured intracranial aneurysms (IA). The pathophysiology of aneurysm formation is largely unknown. Piezo1 mechanoreceptors are expressed in endothelial and smooth muscle cells of developing blood vessels. In addition to hemodynamic forces, Piezo1 has been shown to play an inflammatory role, as stiffness-sensing macrophages lacking Piezo1 exhibit reduced inflammation and enhanced wound healing responses. Malfunction of Piezo1 mechanoreceptors has been implicated in abdominal aortic aneurysm (AAA) development. With the increasing evidence of relationship between AAA and IAs, it is important to study Piezo1 dysregulation as a potential cause of IA development and/or rupture. Methods: During craniotomy for aneurysm clipping of ruptured and unruptured IAs, we excised and collected the aneurysm dome in four patients. Immunohistochemistry (IHC) was performed for Piezo1 and with CD31 to co-localize Piezo1 in the endothelial cells, and a-SMA to co-localize in smooth muscle cells on all aneurysm domes. Additional specimen was saved for genomic analyses. Results: Piezo1 mechanoreceptor overexpression was found in the smooth muscle layer of IAs, but not in superficial temporal artery (STA) controls, in all four human cerebral aneurysm domes. Additionally, there was significant dysregulation of Piezo1 mechanoreceptors in the IA compared with the regular appearance seen in the control human STA (Figure 1). Overexpression was not seen in human arteriovenous malformation specimens. Conclusions: Our data is the first demonstration of overexpression of Piezo1 mechanoreceptors in a disorganized manner in the walls of human IAs, which may represent a therapeutic target. We hypothesize that vascular shear stress leads to Piezo1-mediated disorganization in arterial smooth muscle cells and pro-inflammatory activation, which may lead to IA development and rupture.

Histomorphometric and sympathetic innervation of the human superficial temporal artery

Context:Following microvascular surgeries, stenosis and spasm of the arterial graft or the recipient vessel are serious complications which are often caused by intimal hyperplasia and perivascular nerves, respectively.Aims:The purpose of this study was to understand the characteristics of arterial wall and sympathetic innervation of the human superficial temporal artery (STA) and also, the effect of aging on STA.Methods and Materials:Fifty-two fresh human STA (frontal branch) samples were obtained from 26 cadavers (19 males and 7 females) between the ages of 19 and 83 years. Samples were divided into three age groups: G1, 19-40 years; G2, 41-60 years; G3, over 61 years. 5μm-thin sections of each sample were taken and stained with haematoxylin-eosin, Verhoff's and tyrosine hydroxylase (TH) immunostaining.Results:The well-defined internal elastic lamina (IEL) was observed in all samples of STA, whereas external elastic lamina (EEL) was not prominent in almost all cases or absent in few cases. This might be the important factor in the process of intimal and medial hyperplasia in the frontal branch of STA. Notably, intimal thickening appeared from second decade of life. Sympathetic fibres are located mainly in tunica adventitia and outer media. Mean adventitial and sympathetic areas were found to be 0.080 and 0.010mm2, respectively.Statistical analysis used:One-way ANOVA followed by Tukey HSD post hoc test by using the SPSS 11.5 software.Conclusions:STA is prone to age related pathological changes. Sympathetic index may be used for analysis of sympathetic fibre-related problems (vasospasm, migraine) of the STA.

Histomorphometric and sympathetic innervation of the human superficial temporal artery

ABSTRACT Context: Following microvascular surgeries, stenosis and spasm of the arterial graft or the recipient vessel are serious complications which are often caused by intimal hyperplasia and perivascular nerves, respectively. Aims: The purpose of this study was to understand the characteristics of arterial wall and sympathetic innervation of the human superficial temporal artery (STA) and also, the effect of aging on STA. Methods and Materials: Fifty-two fresh human STA (frontal branch) samples were obtained from 26 cadavers (19 males and 7 females) between the ages of 19 and 83 years. Samples were divided into three age groups: G1, 19-40 years; G2, 41-60 years; G3, over 61 years. 5μm-thin sections of each sample were taken and stained with haematoxylin-eosin, Verhoff's and tyrosine hydroxylase (TH) immunostaining. Results: The well-defined internal elastic lamina (IEL) was observed in all samples of STA, whereas external elastic lamina (EEL) was not prominent in almost all cases or absent in few cases. This might be the important factor in the process of intimal and medial hyperplasia in the frontal branch of STA. Notably, intimal thickening appeared from second decade of life. Sympathetic fibres are located mainly in tunica adventitia and outer media. Mean adventitial and sympathetic areas were found to be 0.080 and 0.010mm2, respectively. Statistical analysis used: One-way ANOVA followed by Tukey HSD post hoc test by using the SPSS 11.5 software. Conclusions: STA is prone to age related pathological changes. Sympathetic index may be used for analysis of sympathetic fibre-related problems (vasospasm, migraine) of the STA.

低出力使用KTPレーザーの脳動脈瘤術中利用の可能性

(Objectives) In clipping operations for cerebral aneurysms, intraoperative rupture of aneurysms is the most serious problem. We evaluated the use of low power KTP (Potassium Titanyl Phosphate)/532TM. laser on cerebral aneurysms during clipping operations and examined the arterial wall affected by this laser histologically. (Methods) Ligh and electron microscopic studies were done on rat common carotid arteries and human superficial temporal arteries irradiated by a 0.05W KTP laser irradiation for 5-30 seconds. In 5 out of 10 clipping operations, the 0.05W KTP laser irradiation was given to the broad neck portion of aneurysms for shrinkage before clipping. Also, all 10 aneurysms were irradiated by the same power laser at the dome portion for coagulation after clipping. (Results) In the light microscopic study, the laser irradiated portion of artery became shrinken without perforation in all materials.Electron microscopic study revealed the vacuolas in the endothelial cells and smooth muscle cells, adhesion or invasion of neutrophils and monocytes to not only the intima but also to the media, and deprivation of endothelial cells in a high dose irradiation. In all clipping operations, the low power KTP laser was effective for shinkage and coagulation of aneurysms. (Conclusions) The low power KTP/532532TM laser was useful in safe and steady clipping operations for cerebral aneurysms.

Ultrastructural localization and translocation of nitric oxide synthase in the endothelium of the human cerebral artery

An electron microscopic immunocytochemical study was undertaken to clarify ultrastructural localization and translocation of nitric oxide synthase (NOS) in endothelial cells (EC) of the human cerebral and superficial temporal arteries (STA) employing antibody against endothelial NOS (EC-NOS). NOS immunoreactivity was found in all EC examined, in association with the plasma membrane and cytoplasmic organelles such as endoplasmic reticulum, Weibel-Palade body and subplasmalemmal, and in the cytoplasm devoid of organelles and extracellular regions, irrespective of arteries. The immunoreactivity in subplasmalemmal vesicles was, however, demonstrated only in human cerebral arteries. In the human STA exposed to bradykinin which induces EC-NOS phosphorylation, the gold particles significantly increased in the cytosol and decreased in the areas associated with cytoplasmic organelles; however, the number of particles did not change significantly in the plasma membrane. The results implicate that NOS may be translocated from the area associated with cytoplasmic organelles to cytosol following EC exposure to bradykinin.

The peptidergic innervation of the human superficial temporal artery: Immunohistochemistry, ultrastructure, and vasomotility

The peptidergic innervation of the human superficial temporal artery was investigated by means of immunohistochemical, ultrastructural, and in vitro pharmacological techniques. A dense network of nerve fibers was found in the adventitia. The majority of the nerve fibers displayed immunoreactivity for tyrosine hydroxylase and neuropeptide Y (NPY). A moderate supply of perivascular nerve fibers displayed either acetylcholinesterase activity or immunoreactivity for vasoactive intestinal peptide (VIP), peptide histidine methionine-27 (PHM), and calcitonin gene-related peptide (CGRP). Only a few nerve fibers displayed substance P (SP), neurokinin A (NKA), and neuropeptide K (NPK) immunoreactivity. In double immunostained preparations, SP immunoreactivity was co-localized with NPK and CGRP in the same nerve fibers. Ultrastructural studies revealed the presence of numerous axon variocosities at the adventitial—medial border. NPY, VIP, and CGRP immunoreactivities occurred in the same type of large granular vesicles, but in morphological distinct nerve profiles. NPY had, in general, no direct vasoconstrictor effect. However, at a low concentration of NPY contractile response induced by NA (10 −7–10 −6 M) was 9–15 times enhanced. The NPY-induced potentiation of the NA-induced contraction was not dependent on the presence of an intact endothelium. No significant difference was found between acetylcholine, VIP, and PHM in either potency or degree of relaxation. SP, NKA, and CGRP also acted as vasodilatory agents, with CGRP being more potent than the tachykinins. The response to SP, but not CGRP, was dependent on an intact endothelium. Pretreatment of the vessels with a low concentration of NPY did not change the responses to ACh, VIP, SP, or CGRP.

Human endothelin ET A receptor antisense oligodeoxynucleotides inhibit endothelin-1 evoked vasoconstriction

Antisense oligodeoxynucleotides to endothelin ET A receptor mRNA were used to characterize vascular smooth muscle receptors. The concentration-response curve showed a significant attenuation of endothelin-1-induced contraction in circular segments of the human superficial temporal artery. Endothelin ET B receptor antisense or mismatch oligodeoxynucleotides showed no alteration of the endothelin-1-induced contraction. Complementary experiments with the selective endothelin ET A receptor antagonist FR139317 demonstrated a shift of the concentration-response curve to the right in a competitive manner (pA 2 = 6.93). The specific method of using the receptor antisense oligodeoxynucleotides approach revealed the presence of endothelin ET A receptors mediating contraction in the human superficial temporal artery.

The peptidergic innervation of the human superficial temporal artery: Immunohistochemistry, ultrastructure and vasomotility

The peptidergic innervation of the human superficial temporal artery: Immunohistochemistry, ultrastructure and vasomotility

Small arteries can be accurately studied in vivo, using high frequency ultrasound

We have validated measurements of diameters of the superficial temporal artery and other small arteries in man with a newly developed 20 MHz ultrasound scanner with A, B and M-mode imaging. The diameter of a reference object was 1.202 mm vs. 1.205 mm as measured by stereomicroscopy (nonsignificant). In vitro measurements of porcine carotid arteries could be reproduced with a mean interobserver difference of 0.008 mm, and the repeatability coefficient was 0.04 mm (1.4%). The frontal branch of the human superficial temporal artery (mean 1.24 mm) was measured with intraobserver repeatability coefficients of 0.18 mm (13.8%) to 0.31 mm (23.4%). The interobserver mean difference was 0.01 mm (0.69%) and the interobserver repeatability coefficient was 0.16 mm (11.1%). Pulsatile changes of the cross sectional area of the radial plus the ulnar artery averaged 0.93 mm 2 compared to 0.63 mm 2 by strain-gauge plethysmography (nonsignificant). Pulsations were 4.6% in the radial artery. We conclude that high frequency ultrasound provides an accurate and reproducible measure of the diameter of small and medium sized human arteries in vivo.

Density of sympathetic nerve terminals in human superficial temporal arteries: potassium permanganate fixation and monoamine oxidase histochemistry.

The density of sympathetic nerve terminals in human superficial temporal arteries from 5 cases at intra- and extracranial bypass surgery was examined with two histochemical methods, one with potassium permanganate fixation and the other with the new monoamine oxidase staining technique. By potassium permanganate fixation, small cored vesicles containing fibers of noradrenergic nerve terminals made up 29.2% of all nerve fibers in the adventitia. The monoamine oxidase-containing nerves in the adventitia made up 31.4%. According to this study, sympathetic nerve terminal density in human superficial temporal arteries was assumed to consist of approximately 30% of all adventitial nerve terminals. In periadventitial nerve bundles, some unmyelinated axons contained monoamine oxidase activity. Thus, staining is considered to be useful in demonstrating the periadventitial and intervaricose fibers as well as the nerve terminals of sympathetic nerves in human cerebral arteries.

Effects of 5-hydroxytryptamine and ergotamine on human superficial temporal artery.

Isometric tension was recorded in ring preparations of human superficial temporal arteries contracted by noradrenaline (NA), 5-hydroxytryptamine (5-HT), and ergotamine. In contrast to NA and 5-HT, ergotamine induced long-lasting contractions refractive to additional stimulations and resistant to repeated wash-out. When tested against 5-HT, ergotamine acted as a non-competitive antagonist. When repeating the 5-HT stimulations (4.7 x 10(-5) M) the contractile response decreased indicating tachyphylaxis to this agent. As ergotamine revealed both a vasoconstrictive and a 5-HT-blocking activity, the beneficial effect in migraine may be by an interference during both the vasoconstrictory and vasodilatory phases.

Altered extracranial vascular reactivity in patients with cerebral arterial aneurysm: An in vitro study

Isolated human superficial temporal arteries were constricted by the addition of potassium, norepinephrine, and 5-hydroxytryptamine. Different responses occurred when the vessels were taken from patients with ruptured intracranial aneurysm and from patients without cerebral aneurysm. In the aneurysm group, significantly stronger contractions were demonstrated upon exposure to potassium and 5-hydroxytryptamine. Because these agents increase the movement of extracellular calcium into smooth muscle cells in the excitation-contraction coupling process, it is suggested that, in vessels from aneurysm patients, there is enhanced influx of calcium across the cell membrane and that cerebral vasospasm is thus not due to extravascular actions alone.