Biomimetic Transparent Eye Protection Inspired by the Carapace of an Ostracod (Crustacea).

In this study we mimic the unique, transparent protective carapace (shell) of myodocopid ostracods, through which their compound eyes see, to demonstrate that the carapace ultrastructure also provides functions of strength and protection for a relatively thin structure. The bulk ultrastructure of the transparent window in the carapace of the relatively large, pelagic cypridinid (Myodocopida) was mimicked using the thin film deposition of dielectric materials to create a transparent, 15 bi-layer material. This biomimetic material was subjected to the natural forces withstood by the ostracod carapace in situ, including scratching by captured prey and strikes by water-borne particles.

Large proteoglycan complexes and disturbed collagen architecture in the corneal extracellular matrix of mucopolysaccharidosis type VII (Sly syndrome).

Purpose: Deficiencies in enzymes involved in proteoglycan (PG) turnover underlie a number of rare mucopolysaccharidoses (MPS), investigations of which can considerably aid understanding of the roles of PGs in corneal matrix biology. Here, the authors analyze novel pathologic changes in MPS VII (Sly syndrome) to determine the nature of PG-collagen associations in stromal ultrastructure.

Methods: Transmission electron microscopy and electron tomography were used to investigate PG-collagen architectures and interactions in a cornea obtained at keratoplasty from a 22-year-old man with MPS VII, which was caused by a compound heterozygous mutation in the GUSB gene.

Structural collagen alterations in macular corneal dystrophy occur mainly in the posterior stroma.

Purpose: Collagen fibrils in the corneal stroma in macular corneal dystrophy, on average, are more closely spaced than in the normal cornea. This study was conducted to investigate if this occurs uniformly across the stroma or is more prevalent at certain stromal depths.

Methods: Microbeam synchrotron X-ray fiber diffraction patterns were obtained in 25 microm steps across the whole thickness of a thin strip of a macular corneal dystrophy cornea obtained at keratoplasty.

Decorin accumulation contributes to the stromal opacities found in congenital stromal corneal dystrophy.

Purpose: Congenital stromal corneal dystrophy (CSCD) is characterized by stromal opacities that morphologically are seen as interlamellar layers of amorphous substance with small filaments, the nature of which has hitherto been unknown. CSCD is associated with truncating mutations in the decorin gene (DCN). To understand the molecular basis for the corneal opacities we analyzed the expression of decorin in this disease, both at the morphologic and the molecular level.

Differential relative sulfation of Keratan sulfate glycosaminoglycan in the chick cornea during embryonic development.

Purpose: To investigate structural remodeling of the developing corneal stroma concomitant with changing sulfation patterns of keratan sulfate (KS) glycosaminoglycan (GAG) epitopes during embryogenesis and the onset of corneal transparency.

Methods: Developing chick corneas were obtained from embryonic day (E)12 to E18 of incubation. Extracellular matrix composition and collagen fibril spacing were evaluated by synchrotron x-ray diffraction, hydroxyproline assay, ELISA (with antibodies against lesser and more highly sulfated KS), and transmission electron microscopy with specific proteoglycan staining.