title: Telomere Length Measurement in Different Ocular Structures: A Potential Implication in Corneal Endothelium Pathogenesis.
abstract: OBJECTIVE
  Human chromosomes are protected at their end by a long portion of hexameric tandem repeats, the telomere. In somatic cells, telomere attrition caused by endogenous and exogenous oxidative stress as well as DNA replication can threaten genomic integrity and lead to the deterioration of tissue functions and an age-related physiological decline. The human eye is a complex organ in which cells of different ocular tissues are exposed to photo-oxidation, high mitochondrial metabolic activity, and/or replicative pressure.
  
  
  METHODS
  We employed a highly sensitive quantitative PCR technique to determine relative telomere length in different human ocular structures.
  
  
  RESULTS
  The longest telomeres in all ocular structures analyzed are found in neural retina, and the shortest are in the cornea. Within the retina, retinal pigment epithelium has four times shorter telomeres when compared to neural retina. However, no age-dependent telomere attrition in the retina and no difference between telomere lengths in the macular region and the rest of the retina have been found. In the cornea, stroma has the longer telomeres. In the corneal endothelium, we found a clear age-dependent telomere shortening. Since the endothelium is one of the most metabolically active ocular structure, this result suggests that endogenous oxidative stress from high mitochondrial activity is a major determinant of telomere loss in this structure.
  
  
  CONCLUSIONS
  Taken together, our results imply that the aging process and telomere attrition in the different ocular structures are the result of multiple factors and could not be attributed to solely exogenous or endogenous oxidation or DNA replication.
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada.
authors: Marie-Catherine
authors: MC
authors: Drigeard Desgarnier
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada.
authors: Corinne
authors: C
authors: Zinflou
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada.
authors: Justin D
authors: JD
authors: Mallet
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada.
authors: Sébastien P
authors: SP
authors: Gendron
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada.
authors: Sébastien J
authors: SJ
authors: Méthot
authors: Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, Québec, Canada 2Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Québec, Canada 3Département d'Ophtalmologie et ORL - Chirurgie Cervico-Faciale, Université Laval, Québec, Québec, Canada.
authors: Patrick J
authors: PJ
authors: Rochette
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D002102:Cadaver; D002648:Child; D003316:Corneal Diseases / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D004728:Endothelium, Corneal / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D060888:Real-Time Polymerase Chain Reaction; D016615:Telomere / Q000235:genetics* / Q000378:metabolism
chemical_list: D004247:DNA