The endothelial glycocalyx: Structure and function in health and critical illness

2020 ◽  
Vol 30 (2) ◽  
pp. 117-134 ◽  
Author(s):  
Sarah Gaudette ◽  
Dez Hughes ◽  
Manuel Boller
2017 ◽  
Vol 595 (15) ◽  
pp. 5015-5035 ◽  
Author(s):  
Kai B. Betteridge ◽  
Kenton P. Arkill ◽  
Christopher R. Neal ◽  
Steven J. Harper ◽  
Rebecca R. Foster ◽  
...  

Author(s):  
Geoffrey Bellingan ◽  
Brijesh V. Patel

Inflammation is the beneficial host response to foreign challenge or tissue injury that ultimately leads to the restoration of tissue structure and function. Critical illness is associated with an overwhelming and prolonged inflammatory activation. Resolution of the inflammatory response is an active process that requires removal of the inciting stimuli, cessation of the pro-inflammatory response, a timely coordinated removal of tissue leukocyte infiltration, a conversion from ‘toxic’ to reparative tissue environment, and restoration of normal tissue structure and function. Mortality may result from deficits in these resolution mechanisms. Improved delivery of critical care through prevention of harm and removal of stimuli has already delivered significant mortality benefits. Most critically-ill patients present with uncontrolled inflammation, hence anti-inflammatory strategies ameliorating this response are likely to be too late and thus futile. Rather, strategies augmenting endogenous pathways involved in the control and appropriate curtailment of such inflammatory responses may promote resolution, repair, and catabasis. Recent evidence showing that inflammation does not simply ‘fizzle out’, but its resolution involves an active and coordinated series of events. Dysfunction of these resolution checkpoints alters the normal inflammatory pathway, and is implicated in the induction and maintenance of states such as ARDS and sepsis. Improved understanding of resolution biology should provide translational pathways to not only improve survival, but also to prevent long-term morbidity resulting from tissue damage.


Author(s):  
Zhengping Hu ◽  
Issahy Cano ◽  
Patricia A. D’Amore

The endothelial glycocalyx is a negatively charged, carbohydrate-rich structure that arises from the luminal surface of the vascular endothelium and is comprised of proteoglycans, glycoproteins, and glycolipids. The glycocalyx, which sits at the interface between the endothelium and the blood, is involved in a wide array of physiological and pathophysiological processes, including as a mechanotransducer and as a regulator of inflammation. Most recently, components of the glycocalyx have been shown to play a key role in controlling angiogenesis. In this review, we briefly summarize the structure and function of the endothelial glycocalyx. We focus on its role and functions in vascular inflammation and angiogenesis and discuss the important unanswered questions in this field.


2019 ◽  
Vol 12 (5) ◽  
pp. 611-619 ◽  
Author(s):  
Onur Yilmaz ◽  
Baris Afsar ◽  
Alberto Ortiz ◽  
Mehmet Kanbay

AbstractThe endothelium is the largest organ in the body and recent studies have shown that the endothelial glycocalyx (eGCX) plays a major role in health and disease states. The integrity of eGCX is vital for homoeostasis and disruption of its structure and function plays a major role in several pathologic conditions. An increased understanding of the numerous pathophysiological roles of eGCX may lead to the development of potential surrogate markers for endothelial injury or novel therapeutic targets. This review provides a state-of-the-art update on the structure and function of the eGCX, emphasizing the current understanding of interorgan crosstalk between the eGCX and other organs that might also contribute to the pathogenesis of kidney diseases.


Author(s):  
Peter Sterling

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.


Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.


Author(s):  
Robert L. Ochs

By conventional electron microscopy, the formed elements of the nuclear interior include the nucleolus, chromatin, interchromatin granules, perichromatin granules, perichromatin fibrils, and various types of nuclear bodies (Figs. 1a-c). Of these structures, all have been reasonably well characterized structurally and functionally except for nuclear bodies. The most common types of nuclear bodies are simple nuclear bodies and coiled bodies (Figs. 1a,c). Since nuclear bodies are small in size (0.2-1.0 μm in diameter) and infrequent in number, they are often overlooked or simply not observed in any random thin section. The rat liver hepatocyte in Fig. 1b is a case in point. Historically, nuclear bodies are more prominent in hyperactive cells, they often occur in proximity to nucleoli (Fig. 1c), and sometimes they are observed to “bud off” from the nucleolar surface.


Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.


2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.


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