Abstract
Purpose There is increasing evidence that abnormal perfusion of the optic nerve head is an important factor involved in the pathophysiology of glaucoma. Transport and distribution of oxygen to the tissues takes place through the erythrocyte membrane. Red blood cell (RBC) acetylcholinesterase (AChE) is a marker of RBC membrane integrity. The aim of this study was to find out whether RBC membrane integrity is preserved in primary open angle glaucoma (POAG), and whether it is modified by the use of topical timolol maleate and pilocarpine.
Method RBC AChE activity was determined ex vivo by Kaplan's spectrophotometric method in 19 POAG patients undergoing topical treatment for glaucoma with timolol, pilocarpine or a combination of the two drugs, and compared with that in 20 controls. To assess the effect of antiglaucomatous therapy in our findings, we carried out an in vitro study in 26 non-glaucomatous patients in which we measured RBC AChE activity after incubation of blood with either timolol maleate, pilocarpine or a combination of the two drugs, using the same spectrophotometric method.
Results There was a significant increase in RBC AChE enzyme activity in POAG patients compared with the control group (p < 0.002). However, timolol and pilocarpine, individually or in combination, have the opposite effect, significantly decreasing RBC AChE activity (p < 0.05).
Conclusion This change in RBC AChE enzyme activity could suggest alterations in RBC membrane integrity in primary open angle glaucoma. Whether or not this finding has implications regarding the microcirculation at the optic nerve head needs to be investigated further.
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Nicolela MT, Hnik P, Drance SM . Scanning laser Doppler flowmeter study of retinal and optic disc blood flow in glaucomatous patients. Am J Ophthalmol 1996;122:775–83.
Hamard P, Hamard H, Dufaux J, Quesnot S . Optic nerve head blood flow using a laser Doppler velocimeter and haemorheology in primary open angle glaucoma and normal pressure glaucoma. Br J Ophthalmol 1994;78:449–53.
Aloin B, Livine A . Acetylcholinesterase as probe for erythrocyte membrane intactness. Biochim Biophys Acta 1974;339:359–66.
Kaplan E, Herz F, Hsu K.S . Erythrocyte acetylcholinesterase activity in ABO haemolytic disease of the newborn. Pediatrics 1964;33:205–11.
Vorhans LJ, Kark RM . Serum cholinesterase in health and disease [review]. Am J Med 1953;14:707–19.
Kaila T, Salminen L, Huupponen R . Systemic absorption of topically applied ocular timolol. J Ocul Pharmacol 1985;l:79–83.
Vuori M-L, Ali-Melkkila T, Kaila T, Lisalo E, Matti Saari K . Plasma and aqueous humour concentrations and systemic effects of topical betaxolol and timolol in man. Acta Oftalmol 1993;71:201–6.
Urtti A, Salminen L, Miinalainen O . Systemic absorption of ocular pilocarpine is modified by polymer matrices. Int J Pharmacol 1985;23:147–61.
Proença C, Vieira ML, Martins e Silva J . Efeito do amiloride, α metildopa e timolol-maleato na actividade da acetilcolinesterase eritocitária e grau de hemólise, in vitro. VII Congresso Nacional de Bioquímica, 1981.
Saldanha C, Quintão T, Garcia C . Avaliação das esterases sanguíneas na doença de Alzheimer. Acta Med Portug 1992;5:591–3.
Souza Ramalho P, Saldanha C, Martins R, Santos D, Cardoso L, Moreira C, Martins e Silva J . Some haemorheological abnormalities in glaucoma. Rev Port Hemorreol 1987;1(Suppl 1):61–4.
Klaver JHJ, Greve EL, Gosling H, Geijssen HC, Hruvelmans HJA . Blood and plasma viscosity measurements in patients with glaucoma. Br J Ophthalmol 1985;69:765–70.
Trope GE, Salinas RG, Glynn M . Blood viscosity in primary open angle glaucoma. Can J Ophthalmol 1987;22:202–4.
Leighton DA, Phillips CI . Systemic blood pressure in open-angle glaucoma, low tension glaucoma and the normal eye. Br J Ophthalmol 1972;56:447–53.
Tielsch JM, Katz J, Sommer A, Quigley HA, Javitt JC Hypertension, perfusion pressure and primary open-angle glaucoma. Arch Ophthalmol 1995;113:216–21.
Proença C, Nogueira JB, Gorjão Clara J, Martins e Silva J, Nogueira da Costa J, Manso C Acetilcolinesterase do eriträcito na hipertensão arterial humana. J Soc Ciâncias Médicas de Lisboa 1977;141:195.
Martins e Silva J, Proença C, Braz Nogueira J, Gorjão Clara J, Manso C Erythrocyte acetylcholinesterase in essential hypertension. J Neur Trans 1980;49:127.
Freitas J, Braz Nogueira J, Nogueira da Costa J, Martins e Silva J . Whole blood filterability and blood oxygen transport in human hypertension. Clin Hemorheol 1983;3:367–73.
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This work was presented as a poster at the Tenth Anniversary Congress of the Royal College of Ophthalmologists, Glasgow 1998
The authors have no financial or proprietary interest in any of the medications studied in this article
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Zabala, L., Saldanha, C., Silva, J. et al. Red blood cell membrane integrity in primary open angle glaucoma: ex vivo and in vitro studies. Eye 13, 101–103 (1999). https://doi.org/10.1038/eye.1999.18
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DOI: https://doi.org/10.1038/eye.1999.18
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