chondroitin-sulfates and Myopia

Topics: Adult; Cell Survival; Chondroitin Sulfates; Complex Mixtures; Corneal Stroma; Corneal Surgery, Laser; Dextrans; Female; Gentamicins; Glycerol; Humans; Male; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Myopia; Organ Preservation; Prospective Studies; Silica Gel; Time Factors

In juvenile tree shrews, positioning a negative-power lens in front of an eye produces a hyperopic shift in refractive state and causes a compensatory increase in axial length over several days so that the eye is myopic when the lens is removed. During negative lens compensation, the scleral extracellular matrix is remodeled. A biomechanical property of the sclera, creep rate, increases; during recovery from induced myopia, the creep rate decreases below normal levels. Changes in glycosaminoglycan (GAG) levels, including those of hyaluronan, may participate in these changes in creep rate and, in turn, participate in controlling the axial length and refractive state. This study investigated the unsulfated and sulfated GAG composition of the sclera during compensation for a -5 diopter (D) lens and during recovery.. Capillary electrophoresis was used to assess the relative levels (ng/mg dry scleral weight) of unsulfated GAGs (hyaluronan [HA] and chondroitin [C0S]), sulfated GAGs (chondroitin-4-sulfate [C4S], chondroitin-6-sulfate [C6S], and dermatan sulfate [DS]) in the sclera of groups of tree shrews (n = 5 per group) that wore a monocular -5 D lens for 1, 2, 4, or 11 days or had 11 days of -5 D lens wear followed by 1, 2, or 4 days of recovery from lens wear. The fellow eye served as an untreated control. Groups of normal and plano lens-treated animals provided age-matched values.. Expressed as a fraction of dry weight, levels of HA were lower after 1, 4, and 11 days of -5 D lens wear. Levels of C0S, C6S, and C4S were significantly lower after 4 and 11 days of lens wear. After 1 and 2 days of recovery, GAG levels in the treated eyes were not significantly different from those in control eyes. After 4 recovery days, HA levels were lower, but the levels of all other GAGs were not different in the recovering and control eyes. Some binocular changes also occurred.. The rapid differential decrease in HA levels during negative lens compensation and the absence of any difference after just 1 day of recovery suggest that HA levels may play a previously unrecognized early role in regulating the biomechanical property (creep rate) of the sclera. The reduced levels of the other GAGs, which occur when creep rate is at its peak elevation, and their rapid return to normal after 1 day of recovery suggest that they may also participate in regulating this biomechanical property of the sclera.

Topics: Animals; Chondroitin; Chondroitin Sulfates; Dermatan Sulfate; Disease Models, Animal; Electrophoresis, Capillary; Female; Hyaluronic Acid; Male; Myopia; Organ Size; Sclera; Sensory Deprivation; Tupaiidae

To analyze the amounts and distributions of nonsulfated and sulfated keratan sulfate (KS) and chondroitin/dermatan sulfate (CS/DS) disaccharides in the interface wound of human postmortem LASIK corneas in comparison with normal control corneas.. Corneal stromal tissue samples from central and paracentral hypocellular primitive stromal interface scars of human LASIK corneas and from similar regions of normal control corneas were collected by laser capture microdissection (LCM) and subsequently were digested with specific glycosidase enzymes. Digests were directly analyzed by electrospray ionization tandem mass spectrometry (ESI-MS/MS).. Concentrations of both monosulfated GlcNAc(6S)-beta-1,3-Gal (MSD2) and disulfated Gal (6S)-beta-1,4-GlcNAc(6S) (DSD) KS disaccharides from the LASIK interface scars were significantly lower than in normal control corneal stromas. No significant difference was found for the concentration of nonsulfated (NSD) KS disaccharides in LASIK interface scars compared with normal controls. The concentration of DeltaUA-beta-1,3-GalNAc(6S) (Deltadi-6S) CS/DS disaccharides from the LASIK interface scar was significantly higher than normal corneal stroma, whereas concentrations of DeltaUA-beta-1,3-GalNAc(4S) (Deltadi-4S) and nonsulfated Deltadi-0S CS/DS disaccharides demonstrated no significant differences from normal corneas.. The profiles of KS and CS/DS disaccharides in LASIK interface scars are significantly different from those in normal cornea stromal tissue, as revealed by LCM and ESI-MS/MS.

Topics: Chondroitin Sulfates; Cicatrix; Cornea; Corneal Stroma; Dermatan Sulfate; Humans; Keratan Sulfate; Keratomileusis, Laser In Situ; Middle Aged; Myopia; Spectrometry, Mass, Electrospray Ionization

To report chondroitin sulfate (CS) concentrations in tear fluid following laser in situ keratomileusis (LASIK).. Fourteen eyes that underwent LASIK were enrolled. We measured the CS isomers chondroitin 4 sulfate and chondroitin 6 sulfate using an enzyme-linked immunosorbent assay preoperatively and postoperatively on days 1 and 4, week 1, and 1 and 3 months.. The chondroitin 4 sulfate concentration remained unchanged from preoperative values. The chondroitin 6 sulfate concentration increased temporarily 1 day postoperatively and gradually decreased thereafter.. CS in tear fluids participates in wound healing after LASIK. Clarifying its role in tear fluids will contribute to improved LASIK outcomes.

Topics: Adult; Astigmatism; Chondroitin Sulfates; Cornea; Enzyme-Linked Immunosorbent Assay; Female; Humans; Keratomileusis, Laser In Situ; Male; Myopia; Tears; Wound Healing

We studied scleral specimens from experimentally induced enlarged eyeball with axial elongation by the transmission electron microscopy following cationic dye (cuplonic blue) staining. The animal model was prepared by the injection of alpha-chymotrypsin into the posterior chamber of young albino rabbits. Cuprolinic blue staining was applied to scleral specimens obtained from equatorial lesion and portions of the scleral tissues were subjected to enzyme digestion by chondroitinase ABC, AC and B before cuprolinic blue staining. In control eyes, dermatan and chondroitin type sulfated proteoglycan filaments were identified. Large, electron dense, and abnormal by shaped proteoglycan filaments were seen in the transmission electron microscopy. Such abnormal proteoglycan filaments were susceptible to enzyme chondroitinase ABC and AC digestion but resistant to chondroitinase B, suggesting that they are chondroitin sulfate dominant proteoglycans. Our morphological data corroborated a previous biochemical report of abnormally induced proteoglycan molecules in sclera with enlarged, axially elongated eyes.

Topics: Animals; Chondroitin Sulfates; Dermatan Sulfate; Microscopy, Electron; Myopia; Proteoglycans; Rabbits; Sclera

The study group consisted of 82 children aged 9 to 14 years with the following forms of myopia: progressive (37 cases), stable (22 cases), congenital stable (11 cases) and incipient (12 cases). During the period of progression in myopia, a significant increase was found in the 24-hour-excretion of acid mucopolysaccharides. In the patients with stable and congenital stable forms the excretion of acid mucopolysaccharides did not differ significantly from that in the control group of emmetropic and hypermetropic children. The results of electrophoresis on cellulose acetate and of the carbazol and orcinol reactions showed predominant excretion of A and C chondroitinsulphates in patients with myopia.

Topics: Adolescent; Child; Chondroitin Sulfates; Dermatan Sulfate; Fundus Oculi; Glycosaminoglycans; Humans; Myopia; Puberty