Revisión Bibliográfica: Glicocálix Endotelial como Blanco de Agresión del Fenómeno Isquemia Reperfusión / Bibliographic Review: Endothelial Glycocalyx as Target of Aggression of the Ischemia-Reperfusion Injury

El glicocálix endotelial es una estructura rica en glucosaminoglicanos, proteoglicanos y glucoproteínas que recubre el endotelio vascular; además de ser una estructura de protección, al estar en contacto directo con la sangre se convierte en el blanco de agresión de diversos mecanismos fisiopatológicos. El fenómeno isquemia-reperfusión se presenta comúnmente en varias entidades del paciente crítico, incluyendo: eventos cerebro vasculares isquémicos, síndrome coronario agudo, sepsis y choque en sus distintos tipos, traumatismos mayores, cirugía y trasplante. Las complicaciones derivadas de este fenómeno son múltiples y dependientes del sitio de presentación; el común denominador es la disfunción microvascular que potencialmente podría desencadenar un fallo multisistémico. El objetivo de esta revisión bibliográfica fue realizar una actualización de los conocimientos en relación a la injuria del glicocálix endotelial durante el fenómeno isquemia-reperfusión.(au)

The endothelial glycocalyx is a structure rich in glycosaminoglycans, proteoglycans and glycoproteins that cover vascular endothelium; in addition of being a protective structure, the direct contact with blood turns it the target of aggression of multiple physiopathological mechanisms. The ischemia-reperfusion injury commonly presents in several critical care entities, including: ischemic stroke, acute coronary syndrome, sepsis and shock, major trauma, surgery and transplantation. Complications are multiple and dependent of the site of presentation; the common denominator is microvascular dysfunction that could potentially trigger multiple organ dysfunction syndrome. The aim of this bibliographic review was to update the knowledge regarding endothelial glycocalyx damage and ischemia-reperfusion injury.(au)

Biophysical Stimuli: A Review of Electrical and Mechanical Stimulation in Hyaline Cartilage.

OBJECTIVE: Hyaline cartilage degenerative pathologies induce morphologic and biomechanical changes resulting in cartilage tissue damage. In pursuit of therapeutic options, electrical and mechanical stimulation have been proposed for improving tissue engineering approaches for cartilage repair. The purpose of this review was to highlight the effect of electrical stimulation and mechanical stimuli in chondrocyte behavior. DESIGN: Different information sources and the MEDLINE database were systematically revised to summarize the different contributions for the past 40 years. RESULTS: It has been shown that electric stimulation may increase cell proliferation and stimulate the synthesis of molecules associated with the extracellular matrix of the articular cartilage, such as collagen type II, aggrecan and glycosaminoglycans, while mechanical loads trigger anabolic and catabolic responses in chondrocytes. CONCLUSION: The biophysical stimuli can increase cell proliferation and stimulate molecules associated with hyaline cartilage extracellular matrix maintenance.

[Profile of sulphated glycosaminoglycans content in the murine uterus during the different phases of the estrous cycle]. / Perfil de glicosaminoglicanos sulfatados no útero de camundongas durante o ciclo estral.

OBJECTIVE: Identification and quantitation of sulphated glycosaminoglycans (GAGs) in the uterus of female mice during the estrous cycle. METHODS: Four groups (n = 10 each) of virgin, 100-day old female mice were assembled according to the estrous cycle phase: proestrus, estrus, metaestrus and diestrus. Samples of the median portion of uterine horns were processed for light microscopy examination (H/E and Alcian blue + PAS). The GAGs were extracted and characterized by agarose gel electrophoresis. Data were analyzed by the unpaired Student's t-test. RESULTS: At light microscopy GAGs appear in all layers of the uterus, especially in the endometrium, between collagen fibers, in the basal membrane and around fibroblasts. Biochemical analyses disclosed presence of dermatan sulphate (DS), chondroitin sulphate (CS and heparan sulphate (HS) during all estral cycle phases. There was no clear electrophoretic separation between DS and CS, thus these two GAGs were considered together (DS+CS) (proestrus = 0.854 +/- 0.192; estrus = 1.073 +/- 0.254; metaestrus = 1.003 +/- 0.255; diestrus = 0.632 +/- 0.443 microg/mg). HS was as follows: proestrus = 0.092 +/- 0.097; estrus = 0.180 +/- 0.141; metaestrus = 0.091 +/- 0.046; diestrus = 0.233 +/- 0.147 microg/mg. The uterine content of DS+CS peaked at estrus (estrogenic action) and that of HS at diestrus (progestagen action). CONCLUSION: Due to a constant turnover process, there are definite alterations in the uterine profile of GAGs content during the estrous cycle in mice, which may be modulated by female sex hormones.

Perfil de glicosaminoglicanos sulfatados no útero de camundongas durante o ciclo estral / Profile of sulphated glycosaminoglycans content in the murine uterus during the different phases of the estrous cycle

OBJETIVOS: Quantificar glicosaminoglicanos sulfatados (GAGs) no útero de camundongas durante o ciclo estral. MÉTODOS: Utilizaram-se quatro grupos de camundongas virgens com 100 dias de idade (n= 10 cada) conforme a fase ciclo estral: proestro, estro, metaestro e diestro. Amostras da porção média dos cornos uterinos foram preparadas para observação em microscopia de luz (H/E e Alcian blue + PAS). Os GAGs foram extraídos e caracterizados por eletroforese em gel de agarose. Os dados foram analisados pelo teste t de Student não pareado. RESULTADOS: A microscopia de luz, os GAGs sulfatados apresentam-se em todas as camadas do útero, em especial no endométrio, entre as fibras colágenas, na membrana basal e ao redor dos fibroblastos. A análise bioquímica mostrou haver dermatam sulfato (DS), condroitim sulfato (CS) e heparam sulfato (HS) durante todas as fases do ciclo estral. Não houve separação eletroforética clara entre DS e CS, de modo que estes dois GAGs foram considerados em conjunto (DS+CS) (proestro = 0,854 ± 0,192; estro = 1,073 ± 0,254; metaestro = 1,003 ± 0,255; e diestro = 0,632 ± 0,443 μg/mg). Os resultados de HS foram: proestro = 0,092 ± 0,097; estro = 0,180 ± 0,141; metaestro = 0,091 ± 0,046; e diestro = 0,233 ± 0,147 μg/mg. A concentração DS+CS apresentou-se maior no estro (ação estrogênica) e a do HS no diestro (ação progestagênica). CONCLUSÃO: Os GAGs no útero de camundongas sofrem alterações durante as fases do ciclo estral, refletindo o constante processo de renovação, sendo modulados pelos hormônios sexuais.

OBJECTIVE: Identification and quantitation of sulphated glycosaminoglycans (GAGs) in the uterus of female mice during the estrous cycle. METHODS: Four groups (n = 10 each) of virgin, 100-day old female mice were assembled according to the estrous cycle phase: proestrus, estrus, metaestrus and diestrus. Samples of the median portion of uterine horns were processed for light microscopy examination (H/E and Alcian blue + PAS). The GAGs were extracted and characterized by agarose gel electrophoresis. Data were analyzed by the unpaired Student's t-test. RESULTS: At light microscopy GAGs appear in all layers of the uterus, especially in the endometrium, between collagen fibers, in the basal membrane and around fibroblasts. Biochemical analyses disclosed presence of dermatan sulphate (DS), chondroitin sulphate (CS and heparan sulphate (HS) during all estral cycle phases. There was no clear electrophoretic separation between DS and CS, thus these two GAGs were considered together (DS+CS) (proestrus = 0.854 ± 0.192; estrus = 1.073 ± 0.254; metaestrus = 1.003 ± 0.255; diestrus = 0.632 ± 0.443 μg/mg). HS was as follows: proestrus = 0.092 ± 0.097; estrus = 0.180 ± 0.141; metaestrus = 0.091 ± 0.046; diestrus = 0.233 ± 0.147 μg/mg. The uterine content of DS+CS peaked at estrus (estrogenic action) and that of HS at diestrus (progestagen action). CONCLUSION: Due to a constant turnover process, there are definite alterations in the uterine profile of GAGs content during the estrous cycle in mice, which may be modulated by female sex hormones.

Bench-to-bedside review: the role of glycosaminoglycans in respiratory disease.

The extracellular matrix (ECM) plays a significant role in the mechanical behaviour of the lung parenchyma. The ECM is composed of a three-dimensional fibre mesh that is filled with various macromolecules, among which are the glycosaminoglycans (GAGs). GAGs are long, linear and highly charged heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units. There are two main types of GAGs: nonsulphated GAG (hyaluronic acid) and sulphated GAGs (heparan sulphate and heparin, chondroitin sulphate, dermatan sulphate, and keratan sulphate). With the exception of hyaluronic acid, GAGs are usually covalently attached to a protein core, forming an overall structure that is referred to as proteoglycan. In the lungs, GAGs are distributed in the interstitium, in the sub-epithelial tissue and bronchial walls, and in airway secretions. GAGs have important functions in lung ECM: they regulate hydration and water homeostasis; they maintain structure and function; they modulate the inflammatory response; and they influence tissue repair and remodelling. Given the great diversity of GAG structures and the evidence that GAGs may have a protective effect against injury in various respiratory diseases, an understanding of changes in GAG expression that occur in disease may lead to opportunities to develop innovative and selective therapies in the future.

Stroma-mediated granulocyte-macrophage colony-stimulating factor (GM-CSF) control of myelopoiesis: spatial organisation of intercellular interactions.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is one of the major cytokines involved in control of haemopoiesis both in bone marrow and in extramedullar sites. Its biological activity depends upon the composition and physicochemical properties of the microenvironment provided by the supporting stroma. GM-CSF activity is modulated and controlled by the stromal heparan-sulphate proteoglycans, but their optimal interaction occurs only at low pH. We questioned whether the microenvironment organisation of the interface between stroma and haemopoietic cells provides such conditions. We studied myeloid progenitor proliferation in contact with bone marrow-derived and extramedullar stromas using electron microscopy and selective labelling of pericellular components. We present evidence that, upon interaction, the two cell types reorganise their interface both in shape and molecular composition. Haemopoietic cells extend projections that considerably increase the area of intercellular contact, and stromal cells form lamellipodia and carry out a redistribution of membrane-associated sialylated glycoconjugates and proteoglycans. Such rearrangements lead to extensive capping of negatively charged molecules at the interface between the supporting stroma and the haemopoietic cells, leading potentially to a local decrease in pH. Our results indicate that the distribution of negative charges at the cellular interface may be responsible for the selectivity of cell response to GM-CSF.

Differential expression of glycosaminoglycans and proteoglycans in the migratory pathway of the primordial germ cells of the mouse.

Primordial germ cells are an embryonic cell line that give rise to gametes in vertebrates. They originate outside the embryo proper and migrate by a well-defined route to the genital ridges. Proteoglycans and glycosaminoglycans have distinctive properties that affect many of the characteristics of the extracellular microenvironment of migratory pathways in a variety of developmental systems. The purpose of this work was to identify the proteoglycans and glycosaminoglycans that are spatially and temporally expressed in the migratory pathway of primordial germ cells. We showed that the expression of proteoglycans and glycosaminoglycans in the primordial germ cells migratory pathway changes according to the different phases of the migratory process. Some molecules such as chondroitin-0-sulfate, decorin, and biglycan are present only in certain phases of the migratory process of primordial germ cells. Heparan sulfate, chondroitin-6-sulfate, versican, perlecan, and syndecan-4, although exhibiting some variation in expression were detected during all phases of the migratory process. Our results indicate that the successive steps of primordial germ cell migration require a coordinated expression of proteoglycans and glycosaminoglycans, that should be present in appropriate levels and in specific areas of the embryo, and that the sequential expression of these extracellular matrix molecules is under a genetic program that appears to be common to a variety of cell types during embryonic development.

Proteinase activity regulation by glycosaminoglycans.

There are few reports concerning the biological role and the mechanisms of interaction between proteinases and carbohydrates other than those involved in clotting. It has been shown that the interplay of enzymes and glycosaminoglycans is able to modulate the activity of different proteases and also to affect their structures. From the large number of proteases belonging to the well-known protease families and also the variety of carbohydrates described as widely distributed, only few events have been analyzed more deeply. The term "family" is used to describe a group of proteases in which every member shows an evolutionary relationship to at least one other protease. This relationship may be evident throughout the entire sequence, or at least in that part of the sequence responsible for catalytic activity. The majority of proteases belong to the serine, cysteine, aspartic or metalloprotease families. By considering the existing limited proteolysis process, in addition to the initial idea that the proteinases participate only in digestive processes, it is possible to conclude that the function of the enzymes is strictly limited to the cleavage of intended substrates since the destruction of functional proteins would result in normal tissue damage. In addition, the location as well as the eventual regulation of protease activity promoted by glycosaminoglycans can play an essential role in the development of several physiopathological conditions.

Human neutrophil migration in vitro induced by secretory phospholipases A2: a role for cell surface glycosaminoglycans.

The purpose of this study was to examine the ability of type I- (porcine pancreas and Naja mocambique mocambique venom), type II- (bothropstoxin-I, bothropstoxin-II, and piratoxin-I), and type III- (Apis mellifera venom) secretory phospholipases A2 (sPLA2s) to induce human neutrophil chemotaxis, and the role of the cell surface proteoglycans, leukotriene B4 (LTB4), and platelet-activating factor (PAF), in mediating this migration. The neutrophil chemotaxis assays were performed by using a 48-well microchemotaxis chamber. Piratoxin-I, bothropstoxin-I, N. m. mocambique venom PLA2 (10-1000 microg/mL each), bothropstoxin-II (30-1000 microg/mL), porcine pancreas PLA2 (0.3-30 microg/mL), and A. mellifera venom PLA2 (30-300 microg/mL) caused concentration-dependent neutrophil chemotaxis. Heparin (10-300 U/mL) concentration-dependently inhibited the neutrophil migration induced by piratoxin-I, bothropstoxin-II, and N. m. mocambique and A. mellifera venom PLA2s (100 microg/mL each), but failed to affect the migration induced by porcine pancreas PLA2. Heparan sulfate (300 and 1000 microg/mL) inhibited neutrophil migration induced by piratoxin-I, whereas dermatan sulfate and chondroitin sulfate (30-1000 microg/mL each) had no effect. Heparitinase I and heparinase (300 mU/mL each) inhibited by 41.5 and 47%, respectively, piratoxin-I-induced chemotaxis, whereas heparitinase II and chondroitinase AC failed to affect the chemotaxis. The PAF receptor antagonist WEB 2086 (3-[4-(2-chlorophenyl)-9-methyl-6H-thienol-[3,2-f] -triazolo-[4,3-a] -diazepine-2-yl]-1-(4-morpholynil)-1-propionate) (0.1-10 microM) and the LTB4 synthesis inhibitor AA-861 [2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benzoquinone] (0.1-10 microM) significantly inhibited the piratoxin-I-induced chemotaxis. Piratoxin-I (30-300 microg/mL) caused a concentration-dependent release of LTB4. Our results suggest that neutrophil migration in response to sPLA2s is independent of PLA activity, and involves an interaction of sPLA2s with cell surface heparin/heparan binding sites triggering the release of LTB4 and PAF.

Cuantificación de glicosaminoglicanos sulfatados en tejidos gingival supracrestal durante movimiento ortodóntico rotacional / Quantification of sulfated glycosaminoglycans in supracrestal gingival tissue during rotational orthodontic movement

La recidiva dental luego del movimiento ortodóntico puede estar relacionada con un deficiente remodelado del tejido gingival. La reparación tisular involucra la regulación de los procesos celulares de proliferación, migración y diferenciación por parte de glicosaminoglicanos sulfatados (S-GAGs) y ácido hialurónico (HA). El estudio del comportamiento de los glicosaminoglicanos (GAGs) podría contribuir a clarificar los eventos clínicos de recidiva. El propósito de este estudio fue cuantificar el contenido de S-GAGs en tejido gingival de bicúspides expuestos a fuerzas rotacionales. 16 primeros bicúspides fueron expuestos a una fuerza rotacional de 4 onzas, por 1, 5, 10 y 20 días. Los bicúspides contralaterales se utilizaron como controles internos. En ambos grupos se tomaron biopsias de tejido gingival supracrestal vestibular. Luego de determinar el peso húmedo de la muestra, el tejido fue solubilizado y las cadenas de S-GAGs fueron extraidas con papaína (Antonopoulos et al, 1964). La formación de complejos solubles de S-GAGs y Alcian Blue fue cuantificada por espectrofotometría de acuerdo con el método modificado de Gold (1981). La absorbancia de cada muestra fue estimada por medio de la ecuación de la curva standard. La concentración de S-GAGs fue expresada en ug/mg de tejido húmedo. Después de un día de aplicación de la fuerza, la concentración de S-GAGs de las muestras experimentales fue, en promedio, 56.59 por ciento mayor que en los controles. Sin embargo, después de 5, 10 y 20 días de aplicación de la fuerza, la concentración de S-GAGs fue, respectivamente, 32.38 por ciento, 23.9 por ciento y 47.64 por ciento menor que en los controles. Los resultados sugieren una correlación inversa entre la duración de la rotación ortodóntica y los niveles gingivales de S-GAGs. El icnremento en S-GAGs luego de un día de aplicación de fuerza podría estar relacionado con una respuesta inflamatoria incial (Yamasaki, 1982). El posterior descenso podría ser una respuesta al stress tensional al cual fue sometido el tejido (Mills et al., 1992)

Proteoglycans in skeletal muscle.

1. Proteoglycans are macromolecules composed of a protein and one or more chains of sulfated carbohydrates, the glycosaminoglycans. Proteoglycans are found on the cell surface and in the extracellular matrix participating in the cell-cell and cell-extracellular matrix interaction. In this review I present the information accumulated in the past years regarding the presence, characteristics, localization, control of expression and alteration in some pathological states of skeletal muscle proteoglycans. 2. This review presents and discusses current information in this area and some projections for the future in four sections: first, the proteoglycans present in embryonic cells and cell lines from skeletal muscle. Second, the presence of proteoglycans in adult skeletal muscles. Third, the regulation of the expression of skeletal muscle proteoglycans, and fourth, skeletal muscle proteoglycans in pathological conditions.

Proteoglycans in skeletal muscle

1. Proteoglycans are macromolecules composed of a protein and one or mor chains of sulfated carbohydrates, the glycosaminoglycans. Proteoglycans are found on the cell surface and in the extracellular matrix participating in the cell-cell-extracellular matrizx interaction. In this review I present the information accumulated in the past years regarding the presence, characteristics, localization, control of expression and alteration in some pathological states of skeletal muscle proteoglycans. 2. This review presents and discusses current information in this area and some projections for the future in four sections: first, the proteoglycans present in embryonic cells and cell lines from skeletal muscle. Second, the presence of proteoglycans in adult skeletal muscles. Third, the regulation of the expression of skeletal muscle proteoglycans, and fourth, skeletal muscle proteoglycans in pathological conditions

Implications of naturally occurring variations in arterial glycosaminoglycans for the pathogenesis of atherosclerosis

Proteoglycans and their constituent glycosaminoglycan (GAG) side chains participate in the pathogenesis of atherosclerosis by holding and modifying plasma lipoproteins (LDL). Of the GAGs existing in arteries, only chondroitin sulfate and dermatan sulfate interact with LDL.In addition, these LDL-binding GAGs show some naturally occurring variations that have direct consequences to their participation in atherogenesis. These variations are: (1) Polydispersity: GAGs normally vary widely in molecular weight and in human aortas there are longer chains of chondroitin sulfate/dermatan sulfate presenting stronger affinity to LDL; (2) Ageing: steric factors play a role in GAG-LDL interaction, and with ageing there is an increase in the relative content of the 6-sulfated isomer of aortic chondroitin sulfate; this isomer binds to LDL, whereas the 4-sulfated isomer does not: (3) Anatomic heterogeneity: The risk to develop atherosclerotic lesions is different among arteries, and the composition and LDL binding affinity of chondroitin sulfate/dermatan sulfate from normal arteries correlate with their susceptibility to atherosclerosis. The participation of GAGs in atherosclerosis should therefore be viewed as variable.

Pharmacological demonstration of a barrier for protease, peptides and acetylcholine in the endometrium of the rat.

Contractions of the rat uterus in response to trypsin, kallikrein, bradykinin, angiotensin II, oxytocin and acetylcholine, were abolished when an inside-out preparation was used. Sensitivity to Ba++, however, was preserved. In preparations in which the endometrium was mechanically removed, all above cited agonists elicited contractions. By treating the uterus with both collagenase and hyaluronidase, acetylcholine was able to induce a contraction when applied to the endometrium side of the uterus. The results show that a barrier for protease, peptides and acetylcholine is present in the mucosa of the rat uterus.

Unidad fetoplacentaria: glicosaminoglicanos: placentas normales / Feto-placentary unit: glycosaminoglycanos: normal placentas

Se describen los glicosaminoglicanos y su importancia en la fisiología placentaria

A model for cell-cell recognition and control of cell growth mediated by sulfated glycosaminoglycans.

This review describes some structural details and the metabolism of the sulfated glycosaminoglycans in animal cells in a variety of physiological conditions and presents views on the possible role that these compounds may play in cell self-recognition, neoplastic transformation and in the control of cell growth.