Group II phospholipase A2 content of tears in patients with senile cataract and primary open-angle glaucoma

Biomarkers in primary open angle glaucoma

Glaucoma, a leading cause of blindness worldwide, is currently defined as a disturbance of the structural or functional integrity of the optic nerve that causes characteristic atrophic changes in the optic nerve, which may lead to specific visual field defects over time. This disturbance usually can be arrested or diminished by adequate lowering of intraocular pressure (IOP). Glaucoma can be divided roughly into two main categories, ‘ open angle ’ and ‘ closed angle ’ glaucoma.Open angle, chronic glaucoma tends to progress at a slower rate and patients may not notice loss of vision until the disease has progressed significantly. Primary open angle glaucoma(POAG) is described distinctly as a multifactorial optic neuropathy that is chronic and progressive with a characteristic acquired loss of optic nerve fibers. Such loss develops in the presence of open anterior chamber angles, characteristic visual field abnormalities, and IOP that is too high for the healthy eye. It manifests by cupping and atrophy of the optic disc, in the absence of other known causes of glaucomatous disease. Several biological markers have been implicated with the disease. The purpose of this study was to summarize the current knowledge regarding the non-genetic molecular markers which have been predicted to have an association with POAG but have not yet been validated.

Bactericidal/permeability-increasing protein in lacrimal gland and in tears of healthy subjects

BACKGROUND

To determine the expression of bactericidal/permeability-increasing protein (BPI), a novel antimicrobial molecule, in the main lacrimal gland and its content in tears of young healthy subjects.

METHODS

BPI concentration of tears was measured in 42 healthy volunteers, 13 men and 29 women, with ages ranging from 22 to 30 (mean 24.7+/-2.1) years by a time-resolved fluoroimmunoassay (TR-FIA). Immunohistochemical analysis was made to localize BPI in lacrimal gland and conjunctiva of eight autopsied subjects, two men and six women, with the age range from 44 to 87 (mean 72.3+/-14.9) years.

RESULT

The mean concentration of BPI in tears was 27.8+/-29.5 microg/l, and it decreased with an increase in tear flow rate (P<0.0001). There was no statistically significant difference in BPI content of tears between the genders. BPI was immunohistochemically seen in outer basal epithelial cells of intralobular and excretory ducts, squamous and basal cells of conjunctiva as well as faintly in myoepithelial cell layer of acini. The presence of BPI in the lacrimal gland and in the tear fluid was verified by Western blotting.

CONCLUSIONS

The results indicate that outer basal epithelial cells of lacrimal gland ducts contain BPI, which occurs in a relatively high concentration in tears. BPI may have a substantial antibacterial role in human tears.

Group IIA phospholipase A(2) content in tears of patients having photorefractive keratectomy

PURPOSE

To study the effect of photorefractive keratectomy (PRK) on the concentration of group IIA phospholipase A(2) (GIIAPLA(2)) in tears.

SETTING

Departments of Ophthalmology and Pathology, University of Turku, Turku, and Helsinki University Eye Hospital, Helsinki, Finland.

METHODS

Tear samples were collected from 25 eyes of 23 patients (mean age 32.3 years +/- 8.6 [SD]) preoperatively and 2 and 7 days after PRK. The GIIAPLA(2) concentration in the tears was measured by time-resolved fluoroimmunoassay.

RESULTS

The GIIAPLA(2) concentration was significantly lower and the tear fluid flow rate significantly higher 2 days after PRK than preoperatively. At 7 days, the GIIAPLA(2) concentration and the tear fluid flow-corrected excretion of GIIAPLA(2) were significantly higher than preoperatively and at 2 days. The tear flow rate was also significantly higher than preoperatively.

CONCLUSIONS

The GIIAPLA(2) content in tears decreased 2 days after PRK due to dilution of the GIIAPLA(2) content during hypersecretion of reflex tears. Photorefractive keratectomy caused an increase in the tear flow rate, GIIAPLA(2) concentration, and tear fluid flow-corrected excretion of GIIAPLA(2) in tears 7 days after surgery, enhancing the protection of tears against bacterial infections.

Diurnal variation in group IIa phospholipase A2 content in tears of contact lens wearers and normal controls

PURPOSE

To study the diurnal rhythm in group IIA phospholipase A(2) (GIIAPLA(2)) content of tears and the effect of the wearing time of soft contact lenses (CL) on the content of GIIAPLA(2 )in tears.

METHODS

The GIIAPLA(2 )content of tears was measured by a time-resolved fluoroimmunoassay in 22 healthy controls at 8 a.m., noon, 4 p.m. and 8 p.m. and in 20 CL wearers at 4 p.m. 1-2 days before using CLs and after 4 h (at noon), 8 h (4 p.m.) and 12 h (8 p.m.) use of soft CLs.

RESULTS

The GIIAPLA(2 )content of tears of healthy controls was 80.6+/-47.8 micro g/ml (mean+/-SD). The GIIAPLA(2 )content was lower at 8 a.m. than at noon (p=0.006) and higher at 4 p.m. than at 8 p.m. ( P=0.003). There was no statistically significant difference in the GIIAPLA(2 )content of tears between the CL wearers without CLs (69.47+/-31.2 micro g/ml) and the normal subjects (92.3+/-48.2 micro g/ml) measured at 4 p.m. Compared with healthy controls, the GIIAPLA(2) values in subjects wearing CLs were statistically significantly lower at noon ( P=0.0001) and at 4 p.m. ( P=0.0002).

CONCLUSION

In normal subjects, the GIIAPLA(2) content of tears increased from 8 a.m. to noon and decreased from 4 p.m. to 8 p.m. The use of CLs for 4 h and 8 h caused a decrease in the GIIAPLA(2) content of tears. This difference was not seen at 4 p.m. the day when the CL wearers did not use CLs.

Group IIA phospholipase A2 content of basal, nonstimulated and reflex tears

PURPOSE

To determine the concentration of group IIA phospholipase A2 (GIIAPLA(2)) in basal, nonstimulated and reflex tears of young normal subjects.

METHODS

The GIIAPLA(2) content of tears was measured in left eye of 16 healthy subjects (mean age 24.5 +/- 2.2 years). Five samples were taken from each subject: nonstimulated sample; basal sample in a dark room after topical anesthesia; and reflex tear samples immediately on stimulation by bright light and breathing of the vapor of onions, and 1 and 3 minutes after the onset of tear flow.

RESULTS

The GIIAPLA(2) content of reflex tears was statistically significantly lower than the GIIAPLA(2) content of basal tears, whereas there was no statistically significant difference in the GIIAPLA(2) content between nonstimulated and basal tears.

CONCLUSIONS

The current results indicate that the basal and nonstimulated tears are similar in their GIIAPLA(2) content, and that the GIIAPLA( 2) content of tears decreases with stimulation, possibly due to dilution of GIIAPLA(2) content during reflectory hypersecretion of tears.