Comparing the effect of benzalkonium chloride-preserved, polyquad-preserved, and preservative-free prostaglandin analogue eye drops on cultured human conjunctival goblet cells

Abstract

Purpose: To investigate the effect of benzalkonium chloride (BAK)-preserved latanoprost and bimatoprost, polyquad (PQ)-preserved travoprost, and preservative-free (PF) latanoprost and tafluprost, all prostaglandin analogues (PGAs), on human conjunctival goblet cell (GC) survival. Furthermore, to investigate the effect of BAK-preserved and PF latanoprost on the cytokine secretion from GC.

Methods: Primary human conjunctival GCs were cultivated from donor tissue. Lactate dehydrogenase (LDH) and tetrazolium dye colorimetric (MTT) assays were used for the assessment of GC survival. A cytometric bead array was employed for measuring secretion of interleukin (IL)-6 and IL-8 from GC.

Results: BAK-preserved latanoprost and bimatoprost reduced cell survival by 28% (p = 0.0133) and 20% (p = 0.0208), respectively, in the LDH assay compared to a negative control. BAK-preserved latanoprost reduced cell proliferation by 54% (p = 0.003), BAK-preserved bimatoprost by 45% (p = 0.006), PQ-preserved travoprost by 16% (p = 0.0041), and PF latanoprost by 19% (p = 0.0001), in the MTT assay compared to a negative control. Only PF tafluprost did not affect the GCs in either assay. BAK-preserved latanoprost caused an increase in the secretion of pro-inflammatory IL-6 and IL-8 (p = 0.0001 and p = 0.0019, respectively) compared to a negative control, which PF latanoprost did not.

Conclusion: BAK-preserved PGA eye drops were more cytotoxic to GCs than PQ-preserved and PF PGA eye drops. BAK-preserved latanoprost induced an inflammatory response in GC. Treatment with PF and PQ-preserved PGA eye drops could mean better tolerability and adherence in glaucoma patients compared to treatment with BAK-preserved PGA eye drops.

Keywords: Benzalkonium chloride; Conjunctival goblet cells; Polyquad; Preservative-free; Prostaglandin analogue.

Fig. 1

Relative cell survival of primary cultured human conjunctival goblet cells after 30 min incubation with prostaglandin analogue eye drops assessed by lactate dehydrogenase assays. Results are shown as mean cell survival relative to 100% survival in the control group. The bars indicate the standard deviation. Only p-values < 0.05 are shown. BAK = benzalkonium chloride, PF = preservative-free, PQ = polyquad.

Fig. 2

Relative cell survival of primary cultured human conjunctival goblet cells after 30 min incubation with prostaglandin analogue eye drops assessed by tetrazolium dye colorimetric assays. Results are shown as mean cell survival relative to 100% survival in the control group. The bars indicate the standard deviation. Only p-values < 0.05 are shown. BAK = benzalkonium chloride, PF = preservative-free, PQ = polyquad.

Fig. 3

Ratio of secretion of interleukin (IL)−6 from primary cultured human conjunctival goblet cells after 30 min incubation with benzalkonium chloride (BAK) and preservative-free (PF) latanoprost eye drops compared to a negative control assessed by a cytometric bead array. Bars indicate standard deviation. The brackets show the p-value. Only p-values < 0.05 are shown.

Fig. 4

Ratio of secretion of interleukin (IL)−8 from primary cultured human conjunctival goblet cells after 30 min incubation with benzalkonium chloride (BAK) and preservative-free (PF) latanoprost eye drops compared to a negative control assessed by a cytometric bead array. Bars indicate standard deviation. The brackets show the p-value. Only p-values < 0.05 are shown.