Altered gelatinolytic activity by keratoconus corneal cells

Kenney, M. Cristina; Chwa, Marilyn; Escobar, Ma. del Carmen; Brown, DJ

doi:10.1016/0006-291x(89)91604-5

Cited by 35 publications

(18 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rehany et al (1982) ®rst showed increased collagenolytic activity in keratoconic compared to normal corneae, while Kenney et al (1989) found altered gelatinase (MMP 2) activity in similar groups. Sawaguchi et al (1990) noted a 75 % reduction in a1 proteinase inhibitor, while Fukuchi et al (1994) showed increased levels of lysosomal hydrolases in the conjunctival epithelia of deceased keratoconic patients.…”

Section: Proteolytic Enzymesmentioning

confidence: 96%

Cellular Incursion into Bowman's Membrane in the Peripheral Cone of the Keratoconic Cornea

Sherwin

Brookes

Loh

et al. 2002

Experimental Eye Research

View full text Add to dashboard Cite

Section: Proteolytic Enzymesmentioning

confidence: 96%

Cellular Incursion into Bowman's Membrane in the Peripheral Cone of the Keratoconic Cornea

Sherwin

Brookes

Loh

et al. 2002

Experimental Eye Research

View full text Add to dashboard Cite

“…Bowman's layer and the corneal stroma are then affected secondarily. Accordingly, an abnormality in tissue degradation which is probably due to an altered relationship between the metalloproteinases and their inhibitors has been found in keratoconus [3][4][5][6]21]. Zimmermann et al [2] suggested that predominant enzymatic degraa b dation would primarily affect the glycosaminoglycans, in particular dermatan and keratan sulfate proteoglycans.…”

Section: Discussionmentioning

confidence: 99%

“…The distribution of collagen types [1,2] as well as the posttranslational modification [2] of collagens were found to be within normal ranges. However, increased collagenolytic activities have been detected in keratoconus [3][4][5][6] and a suppressed translation of keratocyte RNA that could affect the synthesis of proteins like collagens has also been found [7,8]. Immunohistochemical as well as biochemical investigations of the noncollagenous extracellular matrix components revealed that keratan sulfate chains are shortened and of lighter molecular weight in keratoconus corneas [9,10].…”

Section: Introductionmentioning

confidence: 99%

Altered Organization of Collagen in the Apex of Keratoconus Corneas

Radner¹,

Zehetmayer²,

Skorpik³

et al. 1998

Ophthalmic Res

View full text Add to dashboard Cite

Purpose: In 15 keratoconus corneas, the three-dimensional arrangement of collagen lamellae was investigated by means of scanning electron microscopy. Methods: Keratoconus corneas without visible scars were obtained during perforating keratoplasty. The noncollagenous matrix of the stroma was removed with sodium hydroxide. Descemet’s membrane was removed mechanically and deeper layers of the stroma were exposed by cutting the tissue tangentially to the corneal surface with an ultramicrotome. The apical and the para-apical regions of keratoconus were compared to the central regions of normal corneas. Results: In the apical regions of 11 out of the 15 keratoconus corneas (73%), the arrangement of the collagen lamellae differs from those of the para-apical regions and normal corneas. Their collagen fibrils form uniform layers and no delimited collagen lamellae can be differentiated. Interlacing between adjacent layers is extremely decreased or even absent. In the para-apical region of keratoconus corneas the three-dimensional arrangement of collagen lamellae does not differ from that in normal corneas. Conclusion: Stromal thinning and conical ectasia in the apex of keratoconus corneas alters the organization of collagen. This will certainly affect the biomechanical properties of the cornea and further lead to a progression of keratoconus irrespective of its primary pathogenesis.

show abstract

“…In particular, it is unclear if the stromal thinning associated with the disease is caused by an enzyme-mediated loss of collagen (Fini et al, 1992;Kenney et al, 1989Kenney et al, , 1994Kenney and Brown, 2003;Rehany et al, 1982;Sawaguchi et al, 1990Sawaguchi et al, , 1994Sawaguchi et al, , 1989Teng, 1963;Zhou et al, 1998), a disruption to fibrillogenesis due to the presence of defective keratocytes (Brookes et al, 2003;Kim et al, 1999;Sherwin et al, 2002;Somodi et al, 1996) or abnormal proteoglycans (Funderburgh et al, 1989), or whether it is due to slippage between lamellae resulting in a redistribution of collagen away from the apex of the cone (Polack, 1976).…”

Section: Introductionmentioning

confidence: 99%

A study of corneal thickness, shape and collagen organisation in keratoconus using videokeratography and X-ray scattering techniques

Hayes

Boote

Tuft

et al. 2007

Experimental Eye Research

View full text Add to dashboard Cite

In keratoconus, the cornea becomes progressively ectactic resulting in severe visual impairment. Here, we use a combination of videokeratography and synchrotron X-ray diffraction to investigate the relationship between corneal shape and thickness, and the distribution and predominant orientation of stromal fibrillar collagen in five keratoconus corneas. In all but the least advanced case, the thinning and ectasia measured in vivo using corneal videokeratography was accompanied by corresponding changes in the relative distribution and orientation of stromal collagen in the excised corneal buttons. Although the most severe case of keratoconus possessed the most pronounced stromal collagen alterations, and only a minor disruption to stromal collagen arrangement was seen in the least advanced case, a variability in the extent of stromal collagen alteration was seen between these clinical extremes. The observed abnormalities in collagen distribution and orientation are consistent with a mechanism of keratoconus progression that involves inter-fibrillar or inter-lamellar slippage causing a redistribution of tissue within the cornea.

show abstract

Altered gelatinolytic activity by keratoconus corneal cells

Cited by 35 publications

References 17 publications

Cellular Incursion into Bowman's Membrane in the Peripheral Cone of the Keratoconic Cornea

Cellular Incursion into Bowman's Membrane in the Peripheral Cone of the Keratoconic Cornea

Altered Organization of Collagen in the Apex of Keratoconus Corneas

A study of corneal thickness, shape and collagen organisation in keratoconus using videokeratography and X-ray scattering techniques

Contact Info

Product

Resources

About