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Elevated dietary salt intake has previously been demonstrated to have dramatic effects on microvascular structure and function. The purpose of this study was to determine whether a high-salt diet modulates physiological angiogenesis in skeletal muscle. Male Sprague-Dawley rats were placed on a control diet (0.4% NaCl by weight) or a high-salt diet (4.0% NaCl) before implantation of a chronic electrical stimulator. After seven consecutive days of unilateral hindlimb muscle stimulation, animals on control diets demonstrated a significant increase in microvessel density in the tibialis anterior muscle of the stimulated hindlimb relative to the contralateral control leg. High salt-fed rats demonstrated a complete inhibition of this angiogenic response, as well as a significant reduction in plasma ANG II levels compared with those of control animals. To investigate the role of ANG II suppression on the inhibitory effect of high-salt diets, a group of rats that were fed high salt were chronically infused with ANG II at a low dose. Maintenance of ANG II levels restored stimulated angiogenesis to control levels in animals fed a high-salt diet. Western blot analysis indicated that inhibition of angiogenesis in high salt-fed rats was not due to changes in VEGF or VEGF receptor type 1 protein expression in response to stimulation; however, the degree to which VEGF receptor 2 protein increased with stimulation was significantly lower in high salt-fed animals. This study demonstrates an inhibitory effect of high salt intake on stimulated angiogenesis and suggests a critical role for ANG II suppression in mediating this antiangiogenic effect. vascular endothelial growth factor; electrical stimulation

Angiotensin II is known to stimulate angiogenesis in the peripheral circulation through activation of the angiotensin II type 1 (AT1) receptor. This study investigated the effect of angiotensin receptor blockade on cerebral cortical microvessel density. Rats (6-7 wk old, n = 5-17) were instrumented with femoral arterial and venous indwelling catheters for arterial blood pressure measurement and drug administration. Rats were treated for 3 or 14 days with the AT1 receptor blocker losartan (50 mg/day in drinking water) or vehicle. Brains were sectioned and immunostained for CD31, and microvessel density was measured. Treatment with losartan for 3 or 14 days resulted in a slight decrease in mean arterial blood pressure (3 days, 92 [+ or -] mmHg; and 14 days, 99 [+ or -] 2 mmHg) compared with vehicle (109 [+ or -] 3 and 125 [+ or -] 4 mmHg, respectively). A furosemide + captopril 14-day treatment group was added to control for the blood pressure change (96 [+ or -] 3 mmHg). Microvessel density increased in groups treated with losartan for 14 days (429 [+ or -] 13 vessels/[mm.sup.2]) compared with vehicle (383 [+ or -] 11 vessels/[mm.sup.2]) but did not change with furosemide + captopril (364 [+ or -] 7 vessels/[mm.sup.2]). Thus AT1 receptor blockade for 14 days resulted in increased cerebral microvessel density in a blood pressure-independent manner. angiotensin receptor blockers; hypertension; microvascular growth

Angiogenesis within an ischemic region of the brain may increase tissue viability and act to limit the extent of an infarct. The ANG II pathway can both stimulate and inhibit angiogenesis depending on the tissue and the activated receptors. Previous work showed that 2-wk losartan administration (ANG II type 1 receptor blockade) initiates a significant cerebral angiogenic response. We hypothesized that administration of losartan in the drinking water of rats for 2 wk before initiation of focal ischemia would decrease the extent of the resulting infarct. Adult male Sprague-Dawley rats were given losartan (50 mg/day) in drinking water for 2 wk before initiation of cerebral focal ischemia produced by cauterization of cortical surface vessels. Controls received normal drinking water. In control animals, three main vessels feeding the whisker barrel cortex were cauterized, resulting in cessation of blood flow. The same protocol was followed for losartan-treated animals but did not result in cessation of blood flow in the whisker barrel cortex. Another group of losartan-treated animals received between 8 and 14 cauterizations of surface vessels feeding the whisker barrel cortex, and cessation of blood flow was verified. Rats were killed 72 h after surgery. Morphological examination revealed angiogenesis, maintained vascular delivery, and significantly decreased infarct size in losartan-treated animals compared with controls. These results demonstrate that pretreatment with losartan reduces infarct size after cerebral focal ischemia and support the hypothesis that cerebral angiogenesis may be one of the mechanisms responsible. cerebrovascular regulation; rat model; losartan; stroke

We recently described a chymostatin-sensitive elastase-2 as the major angiotensin (ANG) II-forming enzyme in the perfusate of the rat mesenteric arterial bed (MAB) with the same cDNA sequence as rat pancreatic elastase-2. The role of this enzyme in generating ANG II was examined in the rat isolated and perfused MAB. The vasoconstrictor effect elicited by ANG I and the renin substrate tetradecapeptide was only partially inhibited by captopril but abolished by the combination of captopril and chymostatin or N-acetyl-Ala-Ala-Pro-Leu- chloromethylketone (Ac-AAPL-CK; inhibitor originally developed for human elastase-2). The effect induced by [[Pro.sup.11],D-[Ala.sup.12]]- ANG I, an ANG I-converting enzyme (ACE)-resistant biologically inactive precursor of ANG II, was blocked by chymostatin or Ac-AAPL-CK. It was also demonstrated that cultured rat mesenteric endothelial cells synthesize elastase-2 and that mRNA for this enzyme can be detected in different rat tissues such as the pancreas, MAB, lung, heart, kidney, liver, and spleen. In conclusion, the demonstration of a functional alternative pathway to ACE for ANG II generation in the rat MAB and the fact that cultured MAB endothelial cells are capable of producing and secreting elastase-2 represent strong evidence of a physiological role for this enzyme in the rat vasculature. endothelium; chymostatin

An experiment was conducted to investigate the vascular distribution of the angiotensin II type 2 (AT2) receptor in the normal adult vasculature. A polyclonal anti-rat AT2-receptor antiserum was developed and used to demonstrate that AT2-receptor protein could be detected in skeletal muscle and micro-dissected blood vessels by western blot analysis and to determine the micro-anatomic distribution of this receptor in the skeletal muscle microcirculation through the use of immuno-histochemistry. The results are discussed.

Angiotensin II (ANG II) increases the amount of calcium in the nucleus and cytoplasm of aortic smooth muscle cells. This increase in the amount of calcium by ANG II is not temporary and requires activation of both AT1 and AT2 receptors. Blocking either of the receptors removes the effect of ANG II. ANG II is a vasoconstrictor and increases cell proliferation and growth of the blood vessels.

Munzenmaier, Diane H., and David R. Harder. Cerebral microvascular endothelial cell tube formation: role of astrocytic epoxyeicosatrienoic acid release. Am J Physiol Heart Circ Physiol 278: H1163-H1167, 2000.--Cerebral microvascular endothelial cells (CMVEC) form tubes when cocultured with astrocytes (AS). Therefore, it appears that AS may be important in mediating angiogenesis in the brain. We hypothesized that AS modulate CMVEC tube formation by releasing a soluble factor. Thymidine incorporation in cultured CMVEC increased 305% when incubated with 50% conditioned AS medium for 24 h [control: 52,755 [+ or -] 4,838 counts per minute (cpm) per well, conditioned 161,082 [+ or -] 12,099 cpm/well, n = 8]. Because our laboratory has previously shown that AS can produce epoxyeicosatrienoic acids (EETs), which are known mitogens, we investigated whether release of EETs by AS is responsible for tube formation in the CMVEC-AS coculture. AS were seeded on Lab-Tek slides, CMVEC were seeded on the AS the next day, and cultures were allowed to progress for another 5 days with and without cytochrome P-450 epoxygenase blockade by 17-octadecynoic acid (17-ODYA). Tube formation in cocultures receiving 17-ODYA was significantly inhibited compared with control (93.8%). These data suggest that tube formation requires the release of EETs by AS. brain; cerebral circulation; angiogenesis; microcirculation

Background The Pathway Ontology (PW) developed at the Rat Genome Database (RGD), covers all types of biological pathways, including altered and disease pathways and captures the relationships between them within the hierarchical structure of a directed acyclic graph. The ontology allows for the standardized annotation of rat, and of human and mouse genes to pathway terms. It also constitutes a vehicle for easy navigation between gene and ontology report pages, between reports and interactive pathway diagrams, between pathways directly connected within a diagram and between those that are globally related in pathway suites and suite networks. Surveys of the literature and the development of the Pathway and Disease Portals are important sources for the ongoing development of the ontology. User requests and mapping of pathways in other databases to terms in the ontology further contribute to increasing its content. Recently built automated pipelines use the mapped terms to make available the annotations generated by other groups. Results The two released pipelines - the Pathway Interaction Database (PID) Annotation Import Pipeline and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Annotation Import Pipeline, make available over 7,400 and 31,000 pathway gene annotations, respectively. Building the PID pipeline lead to the addition of new terms within the signaling node, also augmented by the release of the RGD "Immune and Inflammatory Disease Portal" at that time. Building the KEGG pipeline lead to a substantial increase in the number of disease pathway terms, such as those within the 'infectious disease pathway' parent term category. The 'drug pathway' node has also seen increases in the number of terms as well as a restructuring of the node. Literature surveys, disease portal deployments and user requests have contributed and continue to contribute additional new terms across the ontology. Since first presented, the content of PW has increased by over 75%. Conclusions Ongoing development of the Pathway Ontology and the implementation of pipelines promote an enriched provision of pathway data. The ontology is freely available for download and use from the RGD ftp site at ftp://rgd.mcw.edu/pub/ontology/pathway/ or from the National Center for Biomedical Ontology (NCBO) BioPortal website at http://bioportal.bioontology.org/ontologies/1035. [ABSTRACT FROM AUTHOR]

Background The Rat Genome Database (RGD) (http://rgd.mcw.edu/) is the premier site for comprehensive data on the different strains of the laboratory rat (Rattus norvegicus). The strain data are collected from various publications, direct submissions from individual researchers, and rat providers worldwide. Rat strain, substrain designation and nomenclature follow the Guidelines for Nomenclature of Mouse and Rat Strains, instituted by the International Committee on Standardized Genetic Nomenclature for Mice. While symbols and names aid in identifying strains correctly, the flat nature of this information prohibits easy search and retrieval, as well as other data mining functions. In order to improve these functionalities, particularly in ontology-based tools, the Rat Strain Ontology (RS) was developed. Results The Rat Strain Ontology (RS) reflects the breeding history, parental background, and genetic manipulation of rat strains. This controlled vocabulary organizes strains by type: inbred, outbred, chromosome altered, congenic, mutant and so on. In addition, under the chromosome altered category, strains are organized by chromosome, and further by type of manipulations, such as mutant or congenic. This allows users to easily retrieve strains of interest with modifications in specific genomic regions. The ontology was developed using the Open Biological and Biomedical Ontology (OBO) file format, and is organized on the Directed Acyclic Graph (DAG) structure. Rat Strain Ontology IDs are included as part of the strain report (RS: ######). Conclusions As rat researchers are often unaware of the number of substrains or altered strains within a breeding line, this vocabulary now provides an easy way to retrieve all substrains and accompanying information. Its usefulness is particularly evident in tools such as the PhenoMiner at RGD, where users can now easily retrieve phenotype measurement data for related strains, strains with similar backgrounds or those with similar introgressed regions. This controlled vocabulary also allows better retrieval and filtering for QTLs and in genomic tools such as the GViewer. The Rat Strain Ontology has been incorporated into the RGD Ontology Browser (http://rgd.mcw.edu/rgdweb/ontology/view.html?acc_id=RS:0000457#s) and is available through the National Center for Biomedical Ontology (http://bioportal.bioontology.org/ontologies/1150) or the RGD ftp site (ftp://rgd.mcw.edu/pub/ontology/rat_strain/). [ABSTRACT FROM AUTHOR]

Background: The use of ontologies to standardize biological data and facilitate comparisons among datasets has steadily grown as the complexity and amount of available data have increased. Despite the numerous ontologies available, one area currently lacking a robust ontology is the description of vertebrate traits. A trait is defined as any measurable or observable characteristic pertaining to an organism or any of its substructures. While there are several ontologies to describe entities and processes in phenotypes, diseases, and clinical measurements, one has not been developed for vertebrate traits; the Vertebrate Trait Ontology (VT) was created to fill this void. Description: Significant inconsistencies in trait nomenclature exist in the literature, and additional difficulties arise when trait data are compared across species. The VT is a unified trait vocabulary created to aid in the transfer of data within and between species and to facilitate investigation of the genetic basis of traits. Trait information provides a valuable link between the measurements that are used to assess the trait, the phenotypes related to the traits, and the diseases associated with one or more phenotypes. Because multiple clinical and morphological measurements are often used to assess a single trait, and a single measurement can be used to assess multiple physiological processes, providing investigators with standardized annotations for trait data will allow them to investigate connections among these data types. Conclusions: The annotation of genomic data with ontology terms provides unique opportunities for data mining and analysis. Links between data in disparate databases can be identified and explored, a strategy that is particularly useful for cross-species comparisons or in situations involving inconsistent terminology. The VT provides a common basis for the description of traits in multiple vertebrate species. It is being used in the Rat Genome Database and Animal QTL Database for annotation of QTL data for rat, cattle, chicken, swine, sheep, and rainbow trout, and in the Mouse Phenome Database to annotate strain characterization data. In these databases, data are also cross-referenced to applicable terms from other ontologies, providing additional avenues for data mining and analysis.The ontology is available at http://bioportal.bioontology.org/ontologies/50138. [ABSTRACT FROM AUTHOR]

The rat has been widely used as a disease model in a laboratory setting, resulting in an abundance of genetic and phenotype data from a wide variety of studies. These data can be found at the Rat Genome Database (RGD, http://rgd.mcw.edu/), which provides a platform for researchers interested in linking genomic variations to phenotypes. Quantitative trait loci (QTLs) form one of the earliest and core datasets, allowing researchers to identify loci harboring genes associated with disease. These QTLs are not only important for those using the rat to identify genes and regions associated with disease, but also for cross-organism analyses of syntenic regions on the mouse and the human genomes to identify potential regions for study in these organisms. Currently, RGD has data on >1,900 rat QTLs that include details about the methods and animals used to determine the respective QTL along with the genomic positions and markers that define the region. RGD also curates human QTLs (>1,900) and houses >4,000 mouse QTLs (imported from Mouse Genome Informatics). Multiple ontologies are used to standardize traits, phenotypes, diseases, and experimental methods to facilitate queries, analyses, and cross-organism comparisons. QTLs are visualized in tools such as GBrowse and GViewer, with additional tools for analysis of gene sets within QTL regions. The QTL data at RGD provide valuable information for the study of mapped phenotypes and identification of candidate genes for disease associations. [ABSTRACT FROM AUTHOR]

The Rat Genome Database (RGD) is the premier resource for genetic, genomic and phenotype data for the laboratory rat, Rattus norvegicus. In addition to organizing biological data from rats, the RGD team focuses on manual curation of gene-disease associations for rat, human and mouse. In this work, we have analyzed disease-associated strains, quantitative trait loci (QTL) and genes from rats. These disease objects form the basis for seven disease portals. Among disease portals, the cardiovascular disease and obesity/metabolic syndrome portals have the highest number of rat strains and QTL. These two portals share 398 rat QTL, and these shared QTL are highly concentrated on rat chromosomes 1 and 2. For disease-associated genes, we performed gene ontology (GO) enrichment analysis across portals using RatMine enrichment widgets. Fifteen GO terms, five from each GO aspect, were selected to profile enrichment patterns of each portal. Of the selected biological process (BP) terms, 'regulation of programmed cell death' was the top enriched term across all disease portals except in the obesity/metabolic syndrome portal where 'lipid metabolic process' was the most enriched term. 'Cytosol' and 'nucleus' were common cellular component (CC) annotations for disease genes, but only the cancer portal genes were highly enriched with 'nucleus' annotations. Similar enrichment patterns were observed in a parallel analysis using the DAVID functional annotation tool. The relationship between the preselected 15 GO terms and disease terms was examined reciprocally by retrieving rat genes annotated with these preselected terms. The individual GO term-annotated gene list showed enrichment in physiologically related diseases. For example, the 'regulation of blood pressure' genes were enriched with cardiovascular disease annotations, and the 'lipid metabolic process' genes with obesity annotations. Furthermore, we were able to enhance enrichment of neurological diseases by combining 'G-protein coupled receptor binding' annotated genes with 'protein kinase binding' annotated genes. [ABSTRACT FROM AUTHOR]

The Rat Genome Database (RGD) is the premier repository of rat genomic and genetic data and currently houses over 40 000 rat gene records as well as human and mouse orthologs, 1771 rat and 1911 human quantitative trait loci (QTLs) and 2209 rat strains. Biological information curated for these data objects includes disease associations, phenotypes, pathways, molecular functions, biological processes and cellular components. A suite of tools has been developed to aid curators in acquiring and validating data objects, assigning nomenclature, attaching biological information to objects and making connections among data types. The software used to assign nomenclature, to create and edit objects and to make annotations to the data objects has been specifically designed to make the curation process as fast and efficient as possible. The user interfaces have been adapted to the work routines of the curators, creating a suite of tools that is intuitive and powerful. [ABSTRACT FROM AUTHOR]

Angiotensin II is known to stimulate angiogenesis in the peripheral circulation through activation of the angiotensin II type I (AT1) receptor. This study investigated the effect of angiotensin receptor blockade on cerebral cortical microvessel density. Rats (6–7 wk old, n = 5–17) were instrumented with femoral arterial and venous indwelling catheters for arterial blood pressure measurement and drug administration. Rats were treated for 3 or 14 days with the AT1 receptor blocker losartan (50 mg/day in drinking water) or vehicle. Brains were sectioned and immunostained for CD31, and microvessel density was measured. Treatment with losartan for 3 or 14 days resulted in a slight decrease in mean arterial blood pressure (3 days, 92 ± 1 mmHg; and 14 days, 99 ± 2 mmHg) compared with vehicle (109 ± 3 and 125 ± 4 mmHg, respectively). A furosemide + captopril 14-day treatment group was added to control for the blood pressure change (96 ±3 mmHg). Microvessel density increased in groups treated with losartan for 14 days (429 ± 13 vessels/mm2) compared with vehicle (383 ± 11 vessels/mm2) but did not change with furosemide + captopril (364 ± 7 vessels/mm2). Thus AT1 receptor blockade for 14 days resulted in increased cerebral microvessel density in a blood pressure-independent manner. [ABSTRACT FROM AUTHOR]

Leaders in the fields of Temporomandibular Disorders (TMD) and its accompanying overlapping pain conditions presented their latest findings at the Seventh Scientific Meeting of The TMJ Association, September 7–9, 2014, in Bethesda, MD. The meeting was co-sponsored by The TMJ Association and the National Institutes of Health. Topics of the scientific sessions included epidemiology and diagnostic criteria, basic mechanisms of chronic pain including the genetic and epigenetic basis of chronic pain, and the development of novel drugs for treatment of these conditions. Discussions were directed toward formulating a set of recommendations to advance research in this field. [ABSTRACT FROM AUTHOR]

The set of interacting molecules collectively referred to as a pathway or network represents a fundamental structural unit, the building block of the larger, highly integrated networks of biological systems. The scientific community's interest in understanding the fine details of how pathways work, communicate with each other and synergize, and how alterations in one or several pathways may converge into a disease phenotype, places heightened demands on pathway data and information providers. To meet such demands, the Rat Genome Database [(RGD) http://rgd.mcw.edu] has adopted a multitiered approach to pathway data acquisition and presentation. Resources and tools are continuously added or expanded to offer more comprehensive pathway data sets as well as enhanced pathway data manipulation, exploration and visualization capabilities. At RGD, users can easily identify genes in pathways, see how pathways relate to each other and visualize pathways in a dynamic and integrated manner. They can access these and other components from several entry points and effortlessly navigate between them and they can download the data of interest. The Pathway Portal resources at RGD are presented, and future directions are discussed.Database URL: http://rgd.mcw.edu [ABSTRACT FROM PUBLISHER]

Aim: We have shown that cerebral angiogenesis is stimulated by chronic treatment of rats with the angiotensin II (ANG II) type 1 receptor (ATIR) antagonist, losartan (LOS). Because the trophic actions of ANG II via AT1R are well known, the finding that an AT1R antagonist increases angiogenesis is paradoxical. The aim is to determine whether cerebral (CMVEC) and dermal (DMVEC) microvascular endothelial cells differ in their growth responses to LOS treatment. Methods: Primary human CMVEC and DMVEC, passage 3-8, were seeded into 9.6-well plates (5000 cells/well) and allowed to adhere for 24 hrs. Cells were exposed to serum-free media (SFM) alone and in the presence of LOS (10 µM), ANG II (1 µM) or both for 48 hours. Cell density was quantified by a fluorescent dye proliferation assay at 480/520 nm. Results: Density of CMVEC increased with either ANG II stimulation (27.5%) or treatment with LOS, with (33.7%) or without ANG II (27.1%) compared to SFM alone. A similar but less robust pattern was seen with DMVEC with ANG II (8.9%), LOS + ANG II (15.2%) and LOS alone (19.0%). Conclusion: This suggests that CMVEC and DMVEC have similar proliferative responses so they do not appear to be tissue-specific. However, LOS alone has a similar effect to treatment with both the agonist and antagonist suggesting that LOS directly stimulates cell proliferation and that the effect is not due to receptor blockade per se. [ABSTRACT FROM AUTHOR]