Increased DNA breaks and up-regulation of both G(1) and G(2) checkpoint genes p21(WAF1/CIP1) and 14-3-3 sigma in circulating leukocytes of glaucoma patients and vasospastic individuals

Amino Acids. 2005 Mar;28(2):199-205. doi: 10.1007/s00726-005-0169-x. Epub 2005 Jan 23.


Objective: Vascular disorder leading to local ischemia/reperfusion has been shown to play an important role in the glaucomatous damage. A decreased expression level of XPGC-gene has been found in circulating leukocytes of normal-tension glaucoma patients. Although decreased activity of XPGC-gene leads to insufficient DNA-repair, no leukopenia has been observed in glaucoma. Molecular mechanisms ensuring cell survival have not been elucidated yet for glaucoma with vascular disorder.

Material and methods: Using the ex vivo optical imaging method of alkaline "comet assay" comparative quantification of DNA breaks was performed in circulating leukocytes of non-glaucomatous non-vasospastic and vasospastic individuals as well as both normal-tension and high-tension glaucoma patients. Relative expression levels of the anti-apoptotic factors P21(WAF1/CIP1) and 14-3-3 sigma were investigated in all groups tested.

Results and conclusions: The quantification of P21(WAF1/CIP1) showed the highest expression rates in high-tension glaucoma patients which were significantly higher than those in all other groups tested. The highest expression rates of 14-3-3 sigma were found in both groups of glaucoma patients. These expression levels correlated well with DNA breaks measured. Since the expression of P21(WAF1/CIP1) in leukocytes was shown to be crucial for their survival under stress conditions, we suppose further that the up-regulation of this gene is the key event in the survival mechanisms of leukocytes in glaucoma accompanied with vascular disorder. The p21(WAF1/CIP1) gene should be further taken into consideration as a potential marker, the up-regulation of which in circulating leukocytes of vasospastic individuals may indicate an increased risk for the developing glaucoma.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / biosynthesis*
  • Adult
  • Aged
  • Aged, 80 and over
  • Cyclin-Dependent Kinase Inhibitor p21 / biosynthesis*
  • DNA Damage*
  • Glaucoma / metabolism*
  • Glaucoma / pathology
  • Humans
  • Leukocytes / metabolism*
  • Leukocytes / pathology
  • Male
  • Middle Aged
  • Reperfusion Injury / metabolism
  • Reperfusion Injury / pathology
  • Up-Regulation*


  • 14-3-3 Proteins
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21