VI.F. Hyaluronidase as a Vitreous Liquefactant

Published on Jan 1, 2014
路 DOI :10.1007/978-1-4939-1086-1_54
Marc D. de Smet31
Estimated H-index: 31
L.R. Grillone6
Estimated H-index: 6
Hyaluronan (HA) is a member of the glycosaminoglycan (GAG) family of polysaccharides, which are composed of repeating disaccharide units, each consisting of hexosamine (usually N-acetylglucosamine or N-acetylgalactosamine) glycosidically linked to either uronic (glucuronic or iduronic) acid or galactose. The nature of the predominant repeating unit is characteristic for each GAG, and the relative amount, molecular size, and type of GAG are said to be tissue specific. GAGs do not normally occur in vivo as free polymers but are covalently linked to a protein core, the ensemble called a proteoglycan [see chapter I.F. Vitreous biochemistry and artificial vitreous]. HA is a GAG that plays an important role as a structural macromolecule in the vitreous. HA is a long, unbranched polymer of the repeating disaccharide glucuronic acid beta 1,3 N-acetylglucosamine, linked by beta l,4 bonds. Its interactions with collagen and other molecular components of the vitreous account for the gel state of the transparent extracellular matrix that is the vitreous [see chapter I.F. Vitreous biochemistry and artificial vitreous], although HA does not likely play a role in mediating vitreoretinal adhesion [see chapter II.E. Vitreo-retinal interface and ILM].
馃摉 Papers frequently viewed together
#1Marc D. de SmetH-Index: 31
Last. Aeilko H ZwindermanH-Index: 1
view all 3 authors...
The vitreous is a complex structure whose composition and appearance change with age. Anomalous adhesions between the posterior vitreous face and the retinal surface are the cause of numerous vitreoretinal complications, while the presence of an intact posterior hyaloid provides a scaffold for vascular growth and anteroposterior traction. This review summarizes what is known about the biochemistry of the vitreous, the process of posterior vitreous detachment (PVD) development, and the available ...
#1Ladislas Robert (University of Paris)H-Index: 51
#2Alexandre Robert (University of Paris)H-Index: 22
Last. G. Renard (University of Paris)H-Index: 3
view all 3 authors...
Abstract Hyaluronan, as most macromolecules of the extracellular matrix, are produced by the differentiated mesenchymal cells. These cells produce also enzymes degrading hyaluronan. This results in the presence of several hyaluronan pools of different molecular weights, all capable of interacting with surrounding cells, mediated by hyaluronan binding proteins and receptors. These interactions modulate cell phenotype and produce a variety of effects conditioning the specific functions of tissues....
OBJECTIVE: To evaluate the feasibility of inducing posterior vitreous detachment (PVD) with pharmacologic vitreolysis in diabetic rats. METHODS: Forty diabetic rats were randomly divided into four groups and treated with different drugs by intravitreous injection respectively as follows: Group A: hyaluronidase (5 U); Group B: plasmin (0.25 U); Group C: hyaluronidase (5 U) plus plasmin (0.25 U); and Group D: balanced salt solution (2 microL). Ten normal rats in Group E were used as controls and w...
The extracellular matrix is a significant barrier to the effective subcutaneous delivery of many drugs, limiting both pharmacokinetic parameters and injection volumes. The space outside adipocytes ...
#1Kesturu S. Girish (University of Mysore)H-Index: 32
#2Kempaiah Kemparaju (University of Mysore)H-Index: 33
Hyaluronan (HA) is a multifunctional high molecular weight polysaccharide found throughout the animal kingdom, especially in the extracellular matrix (ECM) of soft connective tissues. HA is thought to participate in many biological processes, and its level is markedly elevated during embryogenesis, cell migration, wound healing, malignant transformation, and tissue turnover. The enzymes that degrade HA, hyaluronidases (HAases) are expressed both in prokaryotes and eukaryotes. These enzymes are k...
Purpose: The aim of this study was to investigate the extent if recombinant human hyaluronidase (rhuPH20) can enhance trans-scleral penetration of sub-Tenon's dexamethasone (DM) into the posterior segment of the eye. Methods: rhuPH20 was purified from conditioned media through a series of ion exchange, hydrophobic interaction, aminophenylboronate, and hydroxyapatite chromatography to greater than 90% purity based upon specific activity. Only the right eye of each rabbit was injected. The first g...
#1Louis H. Bookbinder (Halozyme Therapeutics)H-Index: 5
#2A. Hofer (Halozyme Therapeutics)H-Index: 1
Last. Gregory I. Frost (Halozyme Therapeutics)H-Index: 19
view all 10 authors...
Subcutaneously injected therapeutics must pass through the interstitial matrix of the skin in order to reach their intended targets. This complex, three-dimensional structure limits the type and quantity of drugs that can be administered by local injection. Here we found that depolymerization of the viscoelastic component of the interstitial matrix in animal models with a highly purified recombinant human hyaluronidase enzyme (rHuPH20) increased the dispersion of locally injected drugs, across a...
#1Trias Ast茅riou (University of Rouen)H-Index: 4
#2Jean-Claude Vincent (University of Rouen)H-Index: 15
Last. Brigitte Deschrevel (University of Rouen)H-Index: 12
view all 4 authors...
Abstract Hyaluronidase and high levels of hyaluronan are found together in tumours. It is highly likely that hyaluronidase activity controls the balance between high molecular mass hyaluronan and oligosaccharides, and thus plays an important role in cancer development. The hyaluronan hydrolysis catalysed by bovine testicular hyaluronidase was studied as a model. The kinetics was investigated at pH 5 and 37 掳C using the colorimetric N -acetyl- d -glucosamine reducing end assay method. While the s...
#1Robert S. Stern (Children's Hospital Oakland Research Institute)H-Index: 139
1.1 Overview of the hyaluronidases The hyaluronidases (Hyals) are classes of enzymes that degrade predominantly hyaluronan (HA). The term 鈥渉yaluronidase鈥 is somewhat of a misnomer since they have the limited ability to degrade chondroitin (Ch) and chondroitin sulfates (ChS), albeit at a slower rate. It is a common misconception that the bacterial Hyals have absolute specificity for HA. This is incorrect. Both bacterial 1 and vertebrate enzymes degrade Ch and ChS, albeit at a slower rate. The pla...
Cited By1
#1Matin Khoshnevis (TU: Temple University)H-Index: 5
#2Jerry SebagH-Index: 33
Anomalous PVD is the fundamental cause of vitreo-maculopathies with vitreo-macular traction and macular pucker, both associated with macular edema.
This website uses cookies.
We use cookies to improve your online experience. By continuing to use our website we assume you agree to the placement of these cookies.
To learn more, you can find in our Privacy Policy.