Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity

Jordan M Burnham,1 Monali Sakhalkar,1 Marlyn P Langford,1 Chanping Liang,1 Thomas B Redens,1 Sushil K Jain21Department of Ophthalmology, 2Department of Pediatrics, Louisiana State University Health Sciences Center, Shreveport, LA, USABackground: Diabetes-related eye disease is due in part to oxidati...

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Autores principales:	Burnham JM, Sakhalkar M, Langford MP, Liang C, Redens TB, Jain SK
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2013
Materias:	Ophthalmology RE1-994
Acceso en línea:	https://doaj.org/article/b8ad029b8f834b38a986b3bf570125d7
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spelling	oai:doaj.org-article:b8ad029b8f834b38a986b3bf570125d72021-12-02T00:15:25ZDiabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity1177-54671177-5483https://doaj.org/article/b8ad029b8f834b38a986b3bf570125d72013-01-01T00:00:00Zhttp://www.dovepress.com/diabetic-and-non-diabetic-human-cornea-and-tear-gamma-glutamyl-transpe-a11929https://doaj.org/toc/1177-5467https://doaj.org/toc/1177-5483Jordan M Burnham,1 Monali Sakhalkar,1 Marlyn P Langford,1 Chanping Liang,1 Thomas B Redens,1 Sushil K Jain21Department of Ophthalmology, 2Department of Pediatrics, Louisiana State University Health Sciences Center, Shreveport, LA, USABackground: Diabetes-related eye disease is due in part to oxidative stress. Gamma-glutamyl transpeptidase (GGT) is a &gamma;-glutamyl cycle enzyme that protects against oxidative stress via glutathione recapture. This study investigates corneal and Schirmer tears GGT activity in diabetic and non-diabetic adults aged 50 to 83 years old.Methods: GGT activity was determined by colorimetric assay on 50 corneas from 14 diabetic (without keratopathy) and 20 non-diabetic donors and on Schirmer type 1 test strips (no anesthesia) of 14 diabetic and 14 non-diabetic subjects.Results: Type 1 (T1) diabetic cornea GGT activity was 40% lower than Type 2 (T2) diabetic cornea GGT activity (P = 0.04), but GGT activity was similar for corneas (without keratopathy) from diabetic and non-diabetic donors (P &ge; 0.44 for all). The number of endothelial cells/unit of GGT activity in diabetic corneas was 22% higher (P = 0.1) than in non-diabetic corneas. GGT activity per Schirmer strip and GGT activity per mm of tears were 36% and 50% higher (P &le; 0.008 for all) for non-diabetic (tear volume dependent) than diabetic donors (tear volume independent), respectively. GGT activity per mm was 50% lower in T1 than T2 diabetics (P = 0.02). Higher tear GGT activity in non-diabetic than diabetic females (P &le; 0.05) was due to higher GGT activity in the African American females.Conclusion: GGT activity was less in T1 than T2 diabetics, but comparable to non-diabetic corneas. Schirmer tear GGT activity in diabetic eyes was tear volume independent, less in T1 than T2, lower than in tear volume dependent, non-diabetic female eyes. Low cornea and tear GGT activity suggests loss of antioxidant potential and supports ocular antioxidant therapy for diabetic patients.Keywords: cornea, diabetes, endothelium, epithelium, eye, &gamma;-glutamyl transpeptidase, tear, oxidative stressBurnham JMSakhalkar MLangford MPLiang CRedens TBJain SKDove Medical PressarticleOphthalmologyRE1-994ENClinical Ophthalmology, Vol 2013, Iss default, Pp 99-107 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Ophthalmology RE1-994
spellingShingle	Ophthalmology RE1-994 Burnham JM Sakhalkar M Langford MP Liang C Redens TB Jain SK Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
description	Jordan M Burnham,1 Monali Sakhalkar,1 Marlyn P Langford,1 Chanping Liang,1 Thomas B Redens,1 Sushil K Jain21Department of Ophthalmology, 2Department of Pediatrics, Louisiana State University Health Sciences Center, Shreveport, LA, USABackground: Diabetes-related eye disease is due in part to oxidative stress. Gamma-glutamyl transpeptidase (GGT) is a &gamma;-glutamyl cycle enzyme that protects against oxidative stress via glutathione recapture. This study investigates corneal and Schirmer tears GGT activity in diabetic and non-diabetic adults aged 50 to 83 years old.Methods: GGT activity was determined by colorimetric assay on 50 corneas from 14 diabetic (without keratopathy) and 20 non-diabetic donors and on Schirmer type 1 test strips (no anesthesia) of 14 diabetic and 14 non-diabetic subjects.Results: Type 1 (T1) diabetic cornea GGT activity was 40% lower than Type 2 (T2) diabetic cornea GGT activity (P = 0.04), but GGT activity was similar for corneas (without keratopathy) from diabetic and non-diabetic donors (P &ge; 0.44 for all). The number of endothelial cells/unit of GGT activity in diabetic corneas was 22% higher (P = 0.1) than in non-diabetic corneas. GGT activity per Schirmer strip and GGT activity per mm of tears were 36% and 50% higher (P &le; 0.008 for all) for non-diabetic (tear volume dependent) than diabetic donors (tear volume independent), respectively. GGT activity per mm was 50% lower in T1 than T2 diabetics (P = 0.02). Higher tear GGT activity in non-diabetic than diabetic females (P &le; 0.05) was due to higher GGT activity in the African American females.Conclusion: GGT activity was less in T1 than T2 diabetics, but comparable to non-diabetic corneas. Schirmer tear GGT activity in diabetic eyes was tear volume independent, less in T1 than T2, lower than in tear volume dependent, non-diabetic female eyes. Low cornea and tear GGT activity suggests loss of antioxidant potential and supports ocular antioxidant therapy for diabetic patients.Keywords: cornea, diabetes, endothelium, epithelium, eye, &gamma;-glutamyl transpeptidase, tear, oxidative stress
format	article
author	Burnham JM Sakhalkar M Langford MP Liang C Redens TB Jain SK
author_facet	Burnham JM Sakhalkar M Langford MP Liang C Redens TB Jain SK
author_sort	Burnham JM
title	Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
title_short	Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
title_full	Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
title_fullStr	Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
title_full_unstemmed	Diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
title_sort	diabetic and non-diabetic human cornea and tear &gamma;-glutamyl transpeptidase activity
publisher	Dove Medical Press
publishDate	2013
url	https://doaj.org/article/b8ad029b8f834b38a986b3bf570125d7
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Diabetic and non-diabetic human cornea and tear &amp;gamma;-glutamyl transpeptidase activity

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