The proteome of mouse cerebral arteries

The cerebral vasculature ensures proper cerebral function by transporting oxygen, nutrients, and other substances to the brain. Distribution of oxygenated blood throughout the neuroaxis takes place at the level of the circle of Willis (CW). While morphologic and functional alterations in CW arteries and its main branches have been reported in cerebrovascular and neurodegenerative diseases, accompanying changes in protein expression profiles remain largely uncharacterized. In this study, we performed proteomics to compile a novel list of proteins present in mouse CW arteries and its ramifications. Circle of Willis arteries were surgically removed from 6-month-old wild-type mice, proteins extracted and analyzed by two proteomics approaches, gel-free nanoLC-mass spectrometry (MS)/MS and gel-based GelLC-MS/MS, using nanoAcquity UPLC coupled with ESI-LTQ Orbitrap XL. The two approaches helped maximize arterial proteome coverage. Six biologic and two technical replicates were performed. In all, 2,188 proteins with at least 2 unique high-scoring peptides were identified (6,630 proteins total). Proteins were classified according to vasoactivity, blood–brain barrier specificity, tight junction and adhesion molecules, membrane transporters/channels, and extracellular matrix/basal lamina proteins. Furthermore, we compared the identified CW arterial proteome with the published brain microvascular proteome. Our database provides a vital resource for the study of CW cerebral arterial protein expression profiles in health and disease.     

Sexual differences in mitochondrial and related proteins in rat cerebral microvessels: A proteomic approach

Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 versus 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1969 proteins, of which 1871 were quantified by TMT labels. Sixty-four proteins were expressed significantly (p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies.     

Effects of prostaglandins on cerebral blood vessels: interaction with vasoactive amines.

Prostaglandins B1 and B2 were topically applied to the pial vessels of mice and arteriolar constriction was observed. This constriction could be significantly increased if serotonin was added to B1, but not when norepinephrine was added. Response to B2 was not enhanced by the simultaneous addition of either serotonin or norepinephrine. Earlier work with prostaglandin F2alpha was replicated. F2alpha constricted pial arterioles and a significantly greater constriction was produced when norepinephrine was applied simultaneously with F2alpha. The data suggest that among the causes of cerebral vasospasm one should consider not only the action of singly agents, but also the combined effects of several agents that might be in contact with cerebral vessels.     

Ontogenesis of alpha- and beta-receptors located on cerebral microvessels

Adrenergic receptors in rat brain microvessels were studied during ontogenesis. Microvessels were prepared by albumin floatation and glass bead filtration techniques from cortices of 10, 20- and 90-day-old rats. The lower level of alpha 1- alpha 2- and beta-receptor sites observed in early life may correlate with the lower capacity of cerebral vascular regulatory mechanism in this period.     

Influence of estrogens on the impedance of cerebral blood vessels

BACKGROUND AND PURPOSE: Recent experimental research has demonstrated the neuroprotective effect of estrogen on the ischemic brain. There is, however, little data available concerning the effects of estrogen on cerebral circulation in humans. In this contribution we studied the influence of endogenous estrogen on the flow in the carotid arteries and on the cerebrovascular impedance. MATERIALS AND METHODS: The plasma concentration of 17-beta-estradiol was measured in 19 healthy, young women over 10 days of the menstrual cycle (days 3, 6, 10, 13-17, 20 and 24). Ultrasound examination of the carotid arteries was performed on the same days using a Toshiba Aplio ultrasound system endowed with a 7.5 MHz linear transducer. Impedance indices based on the recorded systolic, mean and end-diastolic blood flow velocities were calculated for the internal, common and external carotid arteries. RESULTS: During the follicular phase of the menstrual cycle, blood flow in the internal carotid artery increased considerably in all subjects along with increasing plasma concentrations of estrogen. The end-diastolic blood flow velocity increased most significantly, on average by 16% and by up to 24% in individual cases. At the same time, the impedance indices (resistance index--RI and pulsatility index--PI) decreased significantly from their base values. Blood flow velocity in the common carotid artery, the caliber of this vessel, pulse rate and blood pressure remained stable during the entire follicular phase of the cycle. Nevertheless, the flow velocity in the external carotid artery decreased. This suggests that an increase in the cerebral blood flow, promoted by decreasing cerebro-vascular impedance in the follicular phase of the cycle, occurs at the expense of blood "stolen" from the external carotid artery. CONCLUSION: Estrogen increases blood flow in the internal carotid artery by decreasing the impedance of cerebral microcirculation.     

Mitochondrial angiopathy in cerebral blood vessels of mitochondrial eneephalomyopathy

Summary We studied cerebral blood vessels of two autopsied patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). All the main cerebral arteries in the proximal portion at the brain base and more distal portion at the cortical surface, as well as within the brain parenchyma were examined by electron microscopy. There was a striking increase in number of mitochondria in the smooth muscle and endothelial cells, which were most prominent in the pial arterioles and small arteries up to 250 m in diameter and less frequent and severe in the larger pial arteries and intracerebral arterioles and small arteries. These vascular changes have not hitherto been described in MELAS, or in other disorders affecting blood vessels of the brain and other organs. It is suggested that the vascular changes are caused by primary mitochondrial dysfunction in the vascular smooth muscle and endothelial cells of the brain and that they constitute the pathogenic base of the brain lesions and their unusual distribution pattern in MELAS.Supported in part by a grant from the Ministry of Health and Welfare of Japan     

Interaction of heparin with histidine-rich glycoprotein and with antithrombin III

The interaction between heparin, histidine-rich glycoprotein and antithrombin III was studied in purified systems. Histidine-rich glycoprotein binds heparin and thereby interferes with its interaction with antithrombin III, resulting in neutralization of the anticoagulant activity. This interaction occurs with clinical grade heparin as well as with high affinity (for antithrombin III) heparin and with a high affinity heparin fragment with Mr 4,300. Low affinity heparin competes with high affinity heparin for the binding to histidine-rich glycoprotein which results in an apparent increase of the anticoagulant activity of high affinity heparin. The interaction between heparin and histidine-rich glycoprotein is counteracted by Ca2+-binding anticoagulants, indicating that it is dependent on the presence of divalent metal ions. Ethylenediaminetetraacetate is a much more potent inhibitor of the interaction between heparin and histidine-rich glycoprotein than citrate.     

Plasma histidine-rich glycoprotein and plasminogen in patients with liver disease

Histidine-rich glycoprotein (HRG) has been reported to be a fibrinolysis regulating protein due to its capacity to bind to the high affinity lysine binding sites of plasminogen. Using immunological methods we have measured the concentrations in plasma of HRG and total plasminogen and calculated the amounts of plasminogen not bound to HRG (free plasminogen) in 28 patients with moderate to severe liver disease. All three parametres showed wide individual variations, but with decreasing functional capacity of the liver the individual levels of plasminogen were reduced earlier than those of HRG leading to decreased amounts of free plasminogen. Simultaneous determinations of HRG and total plasminogen combined with a calculation of free plasminogen might yield valuable information when evaluating patients for the availability of plasminogen.     

Peptidergic innervation of human cerebral blood vessels and saccular aneurysms

Peptidergic innervation of the human cerebral vasculature has not yet been described in detail and its role in the maintenance of cerebral autoregulation still needs to be established. Similarly, few data exist on the innervation of vascular malformations. The aim of this study was to clarify the peptidergic innervation patterns of human cerebral arteries of various sizes, and, for the first time, that of saccular aneurysms. Light microscopic study of whole-mount preparations of human cerebral arteries and aneurysm sacs resected either during tumor removal or after neck-clipping were carried out by means of silver-intensified light microscopic immunocytochemistry visualizing neuropeptide-Y, calcitonin gene-related peptide and substance P immunoreactivity. Systematic morphological investigations confirmed the presence of longitudinal fiber bundles on the adventitia and a network-like deeper peptidergic system at the adventitia-media border, while in smaller pial and intraparenchymal vessles, only sparse longitudinal immunopositive axons could be detected. The innervation pattern was totally absent in the wall of saccular aneurysms with the complete disappearance of peptidergic nerve fibers in some areas. To the best of our knowledge neither the disappearance of this network on small pial and intraparenchymal vessels, nor the absence of an innervation pattern in saccular aneurysms have been described before. Nonhomogeneous peptidergic innervation of the human cerebral vascular tree might be one of the factors responsible for the distinct autoregulatory properties of the capacitance and resistance vessels. Malfunction of this vasoregulatory system might lead to the impairment of autoregulation during pathological conditions such as subarachnoid hemorrhage. Received: 21 April 1998 / Revised: 7 October 1998, 17 February 1999 / Accepted: 18 February 1999     

Early development of cerebral blood vessels: on the relationship between cerebral histogenesis and internal vascularization

The purpose of this study is to evaluate the morphological relevance to cerebral histogenesis and internal vascularization during early fetal development of rats. Using light and electron microscopes, fetal brains and spinal cords from embryonic day 11 (E11) to E 16 were observed with special attention to new blood vessel formation in the parenchyma. At stages of the neural groove and neural tube blood vessels were confined in the perineural mesenchyma around the matrix cell layer whose cytoarchitecture was arranged in a pseudostratified pattern and did not include the blood vessels. At the prosencephalic stage (E 13), primordium of the striatum which localized in the ventrolateral portion of the cerebral neopallium made up the migrating zone in outer most of the matrix cell layer and blood vessels firstly appeared in this area. Similarly, the blood vessels were also recognized at the ventro-lateral portion of the mesencephalon where the migrating zone was initially formed on E 13. In the cervical spinal cord, the blood vessels were initially recognized on E 12, when the migrating zone was formed at the area of anterior horn. At the early telencephalic stage during E 14-E 15, blood vessels were evenly distributed in the lateral cerebral neopallium, while the cerebral neopallium in the midline where took place later evolution than lateral neopallium was still remaining in the state of matrix cell layer only, and was also lacking the blood vessels. In this area, first appearance of the vessels was E 15 or E 16.(ABSTRACT TRUNCATED AT 250 WORDS)