scholarly journals Perivascular adipose tissue: more than just structural support

2011 ◽  
Vol 122 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Theodora Szasz ◽  
R. Clinton Webb
Keyword(s):  
Adipose Tissue ◽  
Current Knowledge ◽  
Vascular Biology ◽  
Biologically Active ◽  
Perivascular Adipose Tissue ◽  
Structural Support ◽  
Wide Range ◽  
And Migration ◽  
Obesity Hypertension ◽  
And Function

PVAT (perivascular adipose tissue) has recently been recognized as a novel factor in vascular biology, with implications in the pathophysiology of cardiovascular disease. Composed mainly of adipocytes, PVAT releases a wide range of biologically active molecules that modulate vascular smooth muscle cell contraction, proliferation and migration. PVAT exerts an anti-contractile effect in various vascular beds which seems to be mediated by an as yet elusive PVRF [PVAT-derived relaxing factor(s)]. Considerable progress has been made on deciphering the nature and mechanisms of action of PVRF, and the PVRFs proposed until now are reviewed here. However, complex pathways seem to regulate PVAT function and more than one mechanism is probably responsible for PVAT actions in vascular biology. The present review describes our current knowledge on the structure and function of PVAT, with a focus on its role in modulating vascular tone. Potential involvements of PVAT dysfunction in obesity, hypertension and atherosclerosis will be highlighted.

scholarly journals HMBG1 as a Driver of Inflammatory and Immune Processes in the Pathogenesis of Ocular Diseases

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Yi Liu ◽  
Guo-Bin Zhuang ◽  
Xue-Zhi Zhou
Keyword(s):  
Current Knowledge ◽  
High Mobility ◽  
Retinal Cell ◽  
Ocular Diseases ◽  
Wide Range ◽  
Glycation End Products ◽  
Cell Layers ◽  
Proinflammatory Activity ◽  
And Migration ◽  
Proliferation And Migration

High-mobility group box 1 (HMGB1) is a nuclear protein that can also act as an extracellular trigger of inflammation, proliferation, and migration in eye diseases. It induces signaling pathways by binding to the receptor for advanced glycation end products (RAGE) and Toll-like receptors (TLRs) 2, 4, and 9. This proinflammatory activity is considered to be important in the pathogenesis of a wide range of ocular diseases resulting from hemodynamic changes, presence of neovascular endothelial cells, secretion of intraocular immune factors or inflammation, and apoptosis of retinal cell layers. Further work is needed to elucidate in detail how HMGB1 contributes to ocular disease and how its damaging activity can be modulated. In this review, we summarize current knowledge on HMGB1 as a ligand that can evoke inflammation and immune responses in ocular diseases.

THE INTERACTIONS OF VERTEBRATES AND INVERTEBRATES IN PEATLANDS AND MARSHES

1987 ◽  
Vol 119 (S140) ◽  
pp. 15-30 ◽  
Author(s):  
Henry R. Murkin ◽  
Bruce D.J. Batt
Keyword(s):  
Current Knowledge ◽  
Life Cycles ◽  
Future Research ◽  
Aquatic Environments ◽  
Research Needs ◽  
Avian Community ◽  
Wide Range ◽  
Dead Plant ◽  
Living Organisms ◽  
And Function

AbstractThis paper reviews the interactions of vertebrates and invertebrates in peatlands and marshes to assess current knowledge and future research needs. Living organisms may interact through a number of direct trophic and nutrient pathways and a variety of non-trophic, habitat-dependent relationships. Freshwater marshes and peatlands are dynamic aquatic environments and organisms that occupy these areas must be adapted to a wide range of environmental conditions. The avian community illustrates the main interactions of invertebrates and vertebrates in peatlands and marshes. Waterfowl, along with fish and furbearers, are the most economically important vertebrates using these habitats. Each of these groups has important trophic and habitat links to the invertebrates within wetlands.The most common interaction between vertebrates and invertebrates is the use of invertebrates as food by vertebrates. Few studies, however, have dealt with trophic dynamics or secondary production within wetlands. Waterfowl, fish, and many other wetland vertebrates, during all or part of their life cycles, regularly feed on invertebrates. Some invertebrates are vectors of disease and parasites to vertebrates. Vertebrates can directly affect the structural substrate that invertebrates depend on as habitat through consumption of macrophytes or through the use of living and dead plant material in the construction of houses and nests. Conversely, herbivorous invertebrates may directly affect the survival and distribution of macrophytes in wetlands. Macrophyte distribution, in turn, is an important factor in determining vertebrate use of wetlands. The general lack of both taxonomic and ecological information on invertebrates in wetlands is the main hindrance to future elucidation of vertebrate–invertebrate interactions in these environments. Development of invertebrate sampling techniques suitable for wetland habitats also is necessary. More specific research needs must be met to develop a better understanding of the structure and function of these dynamic systems.

scholarly journals Age-Dependent and -Independent Effects of Perivascular Adipose Tissue and Its Paracrine Activities during Neointima Formation

2019 ◽  
Vol 21 (1) ◽  
pp. 282 ◽  
Author(s):  
Eva Schütz ◽  
Rajinikanth Gogiraju ◽  
Maria Pavlaki ◽  
Ioannis Drosos ◽  
George S. Georgiadis ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Smooth Muscle ◽  
Vascular Injury ◽  
Pcr Analysis ◽  
Aortic Tissue ◽  
Neointima Formation ◽  
Middle Aged ◽  
Perivascular Adipose Tissue ◽  
Independent Effects ◽  
And Function

Cardiovascular risk factors may act by modulating the composition and function of the adventitia. Here we examine how age affects perivascular adipose tissue (PVAT) and its paracrine activities during neointima formation. Aortic tissue and PVAT or primary aortic smooth muscle cells from male C57BL/6JRj mice aged 52 weeks (“middle-aged”) were compared to tissue or cells from mice aged 16 weeks (“adult”). Vascular injury was induced at the carotid artery using 10% ferric chloride. Carotid arteries from the middle-aged mice exhibited smooth muscle de-differentiation and elevated senescence marker expression, and vascular injury further aggravated media and adventitia thickening. Perivascular transplantation of PVAT had no effect on these parameters, but age-independently reduced neointima formation and lumen stenosis. Quantitative PCR analysis revealed a blunted increase in senescence-associated proinflammatory changes in perivascular tissue compared to visceral adipose tissue and higher expression of mediators attenuating neointima formation. Elevated levels of protein inhibitor of activated STAT1 (PIAS1) and lower expression of STAT1- or NFκB-regulated genes involved in adipocyte differentiation, inflammation, and apoptosis/senescence were present in mouse PVAT, whereas PIAS1 was reduced in the PVAT of patients with atherosclerotic vessel disease. Our findings suggest that age affects adipose tissue and its paracrine vascular activities in a depot-specific manner. PIAS1 may mediate the age-independent vasculoprotective effects of perivascular fat.

Platelets, inflammation and tissue regeneration

2011 ◽  
Vol 105 (S 06) ◽  
pp. S13-S33 ◽  
Author(s):  
Alan Nurden
Keyword(s):  
Skin Diseases ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Blood Stream ◽  
Cellular Growth ◽  
Biologically Active ◽  
Wide Range ◽  
The Central Nervous System ◽  
Membrane Budding ◽  
And Function

SummaryBlood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from α-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

biomimetic Hydrogel/apatite Nanocomposite Scaffolds for Bone Regeneration

2005 ◽  
Vol 897 ◽  
Author(s):  
Esmaiel Jabbari
Keyword(s):  
Ethylene Oxide ◽  
Bone Regeneration ◽  
Cell Attachment ◽  
Degradation Kinetics ◽  
Bone Matrix ◽  
Biologically Active ◽  
Structural Support ◽  
Cellular Environment ◽  
Gel Phase ◽  
And Migration

AbstractBone is a composite material consisting of aqueous gel and mineral phases. The aqueous gel phase gives bone its form and contributes to its ability to resist tension, while the mineral component resists compression. The combination of a hard inorganic phase and an elastic gel network provides bone with unique mechanical properties as well as a medium for diffusion and release of biologically active agents and it also facilitates communication with the cellular environment. A tissue engineered synthetic biomaterial as a scaffold for bone regeneration should provide temporary structural support to the reconstructed region and a medium for solubilization, diffusion, release of nutrients and growth factors, and their interactions with cells. In this work, the material and biologic properties of a novel synthetic matrix metalloproteinase (MMP) degradable hydrogel/apatite nanocomposite is investigated for its usefulness as a model matrix to mimic the gel and mineral components of the bone matrix and to fabricate aqueous-based scaffolds for bone regeneration. The gel phase is made from poly(lactide-ethylene oxide-fumarate), hereafter designated as PLEOF, terpolymer in which the water content can be adjusted by changing the ratio of the hydrophobic (lactide) to hydrophilic (ethylene oxide) oligomers. The hydrogel and apatite phases are crosslinked using an MMP degradable peptide crosslinker to modulate the matrix degradation kinetics with the migration of bone marrow stromal (BMS) cells. The results demonstrate that MMP degradable scaffolds fabricated from the PLEOF hydrogel and apatite nanoparticles are biocompatible and support cell attachment and migration.

scholarly journals Regional Heterogeneity of Perivascular Adipose Tissue: Morphology, Origin, and Secretome

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinzhi Li ◽  
Zhongyuan Ma ◽  
Yi Zhun Zhu
Keyword(s):  
Adipose Tissue ◽  
Developmental Trajectory ◽  
Low Grade ◽  
Regional Heterogeneity ◽  
Paracrine Factors ◽  
Adipose Tissues ◽  
Perivascular Adipose Tissue ◽  
Wide Range ◽  
Fat Depot ◽  
Low Grade Inflammation

Perivascular adipose tissue (PVAT) is a unique fat depot with local and systemic impacts. PVATs are anatomically, developmentally, and functionally different from classical adipose tissues and they are also different from each other. PVAT adipocytes originate from different progenitors and precursors. They can produce and secrete a wide range of autocrine and paracrine factors, many of which are vasoactive modulators. In the context of obesity-associated low-grade inflammation, these phenotypic and functional differences become more evident. In this review, we focus on the recent findings of PVAT’s heterogeneity by comparing commonly studied adipose tissues around the thoracic aorta (tPVAT), abdominal aorta (aPVAT), and mesenteric artery (mPVAT). Distinct origins and developmental trajectory of PVAT adipocyte potentially contribute to regional heterogeneity. Regional differences also exist in ways how PVAT communicates with its neighboring vasculature by producing specific adipokines, vascular tone regulators, and extracellular vesicles in a given microenvironment. These insights may inspire new therapeutic strategies targeting the PVAT.

scholarly journals N6-methyladenosine (m6A): Revisiting the Old with Focus on New, an Arabidopsis thaliana Centered Review

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 596 ◽  
Author(s):  
Susheel Sagar Bhat ◽  
Dawid Bielewicz ◽  
Artur Jarmolowski ◽  
Zofia Szweykowska-Kulinska
Keyword(s):  
Arabidopsis Thaliana ◽  
Seed Germination ◽  
Plant Development ◽  
Floral Development ◽  
Current Knowledge ◽  
Sequence Motif ◽  
Messenger Rnas ◽  
Specific Sequence ◽  
Wide Range ◽  
And Function

N6-methyladenosine (m6A) is known to occur in plant and animal messenger RNAs (mRNAs) since the 1970s. However, the scope and function of this modification remained un-explored till very recently. Since the beginning of this decade, owing to major technological breakthroughs, the interest in m6A has peaked again. Similar to animal mRNAs, plant mRNAs are also m6A methylated, within a specific sequence motif which is conserved across these kingdoms. m6A has been found to be pivotal for plant development and necessary for processes ranging from seed germination to floral development. A wide range of proteins involved in methylation of adenosine have been identified alongside proteins that remove or identify m6A. This review aims to put together the current knowledge regarding m6A in Arabidopsis thaliana.

scholarly journals Hyaluronan: Metabolism and Function

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1525 ◽  
Author(s):  
Takashi Kobayashi ◽  
Theerawut Chanmee ◽  
Naoki Itano
Keyword(s):  
Extracellular Matrix ◽  
Tissue Concentration ◽  
Molecular Size ◽  
Cellular Functions ◽  
Altered Expression ◽  
Surface Receptors ◽  
Hyaluronan Synthases ◽  
Wide Range ◽  
And Migration ◽  
And Function

As a major polysaccharide component of the extracellular matrix, hyaluronan plays essential roles in the organization of tissue architecture and the regulation of cellular functions, such as cell proliferation and migration, through interactions with cell-surface receptors and binding molecules. Metabolic pathways for biosynthesis and degradation tightly control the turnover rate, concentration, and molecular size of hyaluronan in tissues. Despite the relatively simple chemical composition of this polysaccharide, its wide range of molecular weights mediate diverse functions that depend on molecular size and tissue concentration. Genetic engineering and pharmacological approaches have demonstrated close associations between hyaluronan metabolism and functions in many physiological and pathological events, including morphogenesis, wound healing, and inflammation. Moreover, emerging evidence has suggested that the accumulation of hyaluronan extracellular matrix and fragments due to the altered expression of hyaluronan synthases and hyaluronidases potentiates cancer development and progression by remodeling the tumor microenvironment. In addition to the well-known functions exerted by extracellular hyaluronan, recent metabolomic approaches have also revealed that its synthesis can regulate cellular functions via the reprogramming of cellular metabolism. This review highlights the current advances in knowledge on the biosynthesis and catabolism of hyaluronan and describes the diverse functions associated with hyaluronan metabolism.

scholarly journals Deciphering Adipose Tissue Extracellular Vesicles Protein Cargo and Its Role in Obesity

2020 ◽  
Vol 21 (24) ◽  
pp. 9366
Author(s):  
Tamara Camino ◽  
Nerea Lago-Baameiro ◽  
Aurelio Martis-Sueiro ◽  
Iván Couto ◽  
Francisco Santos ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Extracellular Vesicles ◽  
Metabolic Disorders ◽  
Current Knowledge ◽  
Local Level ◽  
Functional Roles ◽  
Intracellular Proteins ◽  
Key Players ◽  
Membrane Antigens ◽  
And Function

The extracellular vesicles (EVs) have emerged as key players in metabolic disorders rising as an alternative way of paracrine/endocrine communication. In particular, in relation to adipose tissue (AT) secreted EVs, the current knowledge about its composition and function is still very limited. Nevertheless, those vesicles have been lately suggested as key players in AT communication at local level, and also with other metabolic peripheral and central organs participating in physiological homoeostasis, and also contributing to the metabolic deregulation related to obesity, diabetes, and associated comorbidities. The aim of this review is to summarize the most relevant data around the EVs secreted by adipose tissue, and especially in the context of obesity, focusing in its protein cargo. The description of the most frequent proteins identified in EVs shed by AT and its components, including their changes under pathological status, will give the reader a whole picture about the membrane/antigens, and intracellular proteins known so far, in an attempt to elucidate functional roles, and also suggesting biomarkers and new paths of therapeutic action.

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