Human ciliary muscle cell responses to FP-class prostaglandin analogs: phosphoinositide hydrolysis, intracellular Ca2+ mobilization and MAP kinase activation.

Phospholipase C induced phosphoinositide (PI) turnover, intracellular Ca(2+) ([Ca(2+)](i)) mobilization and mitogen-activated protein (MAP) kinase activation by FP-class prostaglandin analogs was studied in normal human ciliary muscle (h-CM) cells. Agonist potencies obtained in the PI turnover assays were: travoprost acid ((+)-fluprostenol; EC(50) = 2.6 +/- 0.8 nM) > bimatoprost acid (EC(50) = 3.6 +/- 1.2 nM) > (+/-)-fluprostenol (EC(50) = 4.3 +/- 1.3 nM) > prostaglandin F(2 alpha) (PGF(2 alpha)) (EC(50) = 134 +/- 17 nM) > latanoprost acid (EC(50) = 198 +/- 83 nM) > S-1033 (EC(50) = 2930 +/- 1420 nM) > unoprostone (EC(50) = 5590 +/- 1490 nM) > bimatoprost (EC(50) = 9600 +/- 1100 nM). Agonist potencies in h-CM cells correlated well with those previously obtained for the cloned human ciliary body-derived FP receptor (r = 0.96, p< 0.001) and that present on h-TM cells (r = 0.94, p< 0.0001). Travoprost acid, PGF(2 alpha) and unoprostone also stimulated [Ca(2+)](i) mobilization in h-CM cells with travoprost acid being the most potent agonist. MAP kinase activity was stimulated in the h-CM cells with the following rank order of activity (at 100 nM): travoprost acid > PGF(2 alpha) > latanoprost acid > PGD(2) > bimatoprost > latanoprost = bimatoprost acid = fluprostenol > PGE(2) = S-1033 > unoprostone > PGI(2). The PI turnover, [Ca(2+)](i) mobilization and MAP kinase activation induced by several of these agonists was blocked by the FP receptor antagonist, AL-8810 (11 beta-fluoro-15-epiindanyl PGF(2 alpha)) (e.g. K(i) = 5.7 microM versus PI turnover). These studies have characterized the biochemical and pharmacological properties of the native FP prostaglandin receptor present on h-CM cells using three signal transduction mechanism assays and a broad panel of FP-class agonist analogs (including free acids of bimatoprost, travoprost and latanoprost) and the FP receptor antagonist, AL-8810.     

Agonist activity of bimatoprost, travoprost, latanoprost, unoprostone isopropyl ester and other prostaglandin analogs at the cloned human ciliary body FP prostaglandin receptor.

We have determined the agonist activity of a number of natural prostaglandins and prostaglandin analogs at the FP prostaglandin receptor cloned from a human ciliary body cDNA library using phosphoinositide (PI) turnover assays. Travoprost acid (EC50 = 3.2 +/- 0.6 nM) was the most potent agonist in these cells followed by bimatoprost free acid (17-phenyl-trinor PGF2alpha; EC50 = 5.8 +/- 2.6 nM), fluprostenol (EC50 = 6.1 +/- 1.5 nM), and latanoprost free acid (PHXA85; EC50 = 54.6 +/- 12.4 nM) which was 17-fold weaker (p < 0.001) than travoprost acid. Unoprostone and S-1033 were significantly (p < 0.001) weaker than travoprost acid. The amide prodrug, bimatoprost (EC50 = 694 +/- 293 nM), activated this FP receptor with an intermediate potency. The isopropyl ester prodrugs, travoprost (EC50 = 42.3 +/- 6.7 nM), latanoprost (EC50 = 126 +/- 347 nM) and unoprostone isopropyl ester (EC50 = 9,100 +/- 2,870 nM), also exhibited FP agonist activity. However, other compounds such as PGI2, bradykinin, histamine, and serotonin were inactive. The agonist activities of bimatoprost, unoprostone (UF-021), fluprostenol and acids of travoprost and latanoprost were antagonized by AL-8810 (11beta-fluoro- 15-epi-15-indanyl-PGF2alpha), an FP-receptor-selective antagonist (Ki = 1.0 - 2.1 microM; n = 3). These studies have demonstrated, for the first time, agonist activities of the currently known and marketed ocular hypotensive prostaglandin analogs at the cloned human ciliary body FP prostaglandin receptor.     

Cat iris sphincter smooth-muscle contraction: comparison of FP-class prostaglandin analog agonist activities.

The pharmacologic characteristics of a number of FP-class prostaglandin (PG) analogs were determined by using the cat iris sphincter smooth-muscle-contraction assay. Cumulative concentration-response curves were generated for each compound. The relative agonist potencies (EC(50)) of the compounds were: cloprostenol (0.0012 +/- 0.0004 nM) > travoprost acid (0.46 +/- 0.13 nM) = bimatoprost acid (0.99 +/- 0.19 nM) > (+/-)-fluprostenol (15.8 +/- 2.6 nM) = PGF(2alpha) (18.6 +/- 1.8 nM) > latanoprost acid (29.9 +/- 1.6 nM) > bimatoprost (140 +/- 45 nM) > S-1033 (588 +/- 39 nM) > unoprostone (UF-021; 1280 +/- 50 nM; n = 4-14). The maximum response induced by travoprost acid (122% +/- 2.3% maximum response relative to PGF(2alpha)) was significantly greater than that induced by all the other PG compounds (P < 0.001 - P < 0.02). Interestingly, the FP-receptor antagonist, AL-8810, behaved as a moderate efficacy partial agonist (EC(50) = 2140 +/- 190 nM; 63 +/- 4.3% maximum response relative to PGF(2alpha)), indicating that the cat iris contains an extremely well-coupled FP-receptor population, and/or the tissue contains an extremely high density of the FP-receptor and/or spare receptors. The cat iris contraction data were well correlated with other FP-receptor-mediated signal-transduction processes, including FP-receptor binding in bovine corpus luteum (r = 0.86), FP-receptor binding in human iris (r = 0.61), phosphoinositide (PI) hydrolysis in human ciliary muscle and trabecular meshwork cells (r = 0.77 - 0.86), PI turnover in rat and mouse cells (r = 0.73 - 0.76) and via cloned human FP-receptor (r = 0.9), and rat uterus contraction (r = 0.84). These data confirm the presence of functional FP-receptors in the cat iris sphincter, which are exquisitely well coupled and which respond to a variety of FP-class PG analogs with differing potencies.     

Unoprostone Isopropyl and Metabolite M1 Activate BK Channels and Prevent ET-1-Induced [Ca2+]i Increases in Human Trabecular Meshwork and Smooth Muscle

Purpose. Effects of cis-unoprostone isopropyl, its primary metabolite M1, trans-unoprostone isopropyl, latanoprost free acid, and fluprostenol were studied on Ca(2+)-activated K(+) (BK) channels, plasma membrane potential, [cAMP](i), [cGMP](i), and steady state [Ca(2+)](i), and protection against endothelin-1 (ET-1)-induced steady state [Ca(2+)](i) increases in human cortical neuronal (HCN-1A), trabecular meshwork (HTMC), and pulmonary artery smooth muscle (PASMC) cells. Effects on recombinant human prostaglandin (PG) receptors were determined. Methods. BK channel currents were measured using whole-cell patch clamp; [cAMP](i), [cGMP](i) with ELISAs; [Ca(2+)](i) with indo-1; plasma membrane potential using diBAC(4)(3); and PG receptor effects with PG receptor-expressing cells and FLIPR fluo-4 Ca(2+) assays. Results. Unoprostone isopropyl and M1 activated sustained iberiotoxin (IbTX)-sensitive, AL-8810 (FP receptor antagonist)-insensitive BK channel currents with EC(50)s of 0.51 ± 0.03 nM (n = 5) and 0.52 ± 0.03 nM (n = 6) in HTMCs; 0.61 ± 0.06 nM (n = 8) and 0.46 ± 0.04 nM (n = 5) for M1 in HCN-1A cells and PASMC, respectively. They caused AL-8810-insensitive, IbTX-sensitive membrane hyperpolarization at 10 nM; up to 100 nM had no effect on or decreased [cAMP](i), [cGMP](i), and [Ca(2+)](i); and prevented ET-1-induced [Ca(2+)](i) increases. In contrast, 10 nM latanoprost free acid and fluprostenol caused membrane depolarization; increased [cAMP](i), [cGMP](i), and [Ca(2+)](i); and did not prevent ET-1-induced [Ca(2+)](i) increases. Trans-unoprostone isopropyl had no effects. Unoprostone isopropyl (1.25 μM) had no effect on PG receptors, and neither did M1, except for activating the FP receptor with EC(50) = 557.9 ± 55.2 nM (n = 4). Conclusions. Prostones, unoprostone isopropyl and M1, are potent AL-8810-insensitive, stereospecific BK channel activators, without [cAMP](i), [cGMP](i), or [Ca(2+)](i) involvement, and prevent ET-1-induced steady state Ca(2+) increases in HTMCs.     

Ocular hypotensive FP prostaglandin (PG) analogs: PG receptor subtype binding affinities and selectivities, and agonist potencies at FP and other PG receptors in cultured cells.

Natural prostaglandins (PGs) such as PGD2, PGE2, PGF2(2alpha), and PGI2 exhibited the highest affinity for their respective cognate receptors, but were the least selective agents when tested in receptor binding assays. Travoprost acid ([+]-fluprostenol) was the most FP-receptor-selective compound, exhibiting a high affinity (Ki = 35 +/- 5 nM) for the FP receptor, and minimal affinity for DP (Ki = 52,000 nM), EP1 (Ki = 9540 nM), EP3 (Ki = 3501 nM), EP4 (Ki = 41,000 nM), IP (Ki > 90,000 nM), and TP (Ki = 121,000 nM) receptors. Travoprost acid was the most potent PG analog tested in FP receptor functional phosphoinositide turnover assays in the following cell types: human ciliary muscle (EC50 = 1.4 nM), human trabecular meshwork (EC50 = 3.6 nM), and mouse fibroblasts and rat aortic smooth muscle cells (EC50 = 2.6 nM). Although latanoprost acid exhibited a relatively high affinity for the FP receptor (Ki = 98 nM), it had significant functional activity at FP (EC50 = 32-124 nM) and EP1 (EC50 = 119 nM) receptors. Bimatoprost acid was less selective, exhibiting a relatively high affinity for the FP (Ki = 83 nM), EP1 (Ki = 95 nM), and EP3 (Ki = 387 nM) receptors. Bimatoprost acid exhibited functional activity at the EP1 (EC50 = 2.7 nM) and FP (EC50 = 2.8-3.8 nM in most cells) receptors. Bimatoprost (nonhydrolyzed amide) also behaved as an FP agonist at the cloned human FP receptor (EC50 = 681 nM), in h-TM (EC50 = 3245 nM) and other cell types. Unoprostone and S-1033 bound with low affinity (Ki = 5.9 microM to > 22 microM) to the FP receptor, were not selective, but activated the FP receptor. In conclusion, travoprost acid has the highest affinity, the highest FP-receptor-selectivity, and the highest potency at the FP receptor as compared to the other ocular hypotensive PG analogs known so far, including free acids of latanoprost, bimatoprost, and unoprostone isopropyl ester.     

Preclinical pharmacology of AL-12182, a new ocular hypotensive 11-oxa prostaglandin analog.

PURPOSE: The aim of this study was to determine selected in vivo ocular properties of AL-12182 (5,6-dihydro-4,5-didehydro-11-deoxy-11-oxa-16-(3-chlorophenoxy)-omega-tetranor-PGF(2alpha) isopropyl ester) and the in vitro profile of its free acid, AL-12180. METHODS: Previously documented radioligand binding and functional assays involving human ciliary muscle cells (h-CM), human trabecular meshwork (h-TM) and other cells, and porcine ocular arteries were utilized. For in vivo procedures, we utilized rabbits, cats, and nonhuman primates to measure hyperemia, pupil diameter, and intraocular pressure (IOP), respectively. RESULTS: AL-12180 exhibited the highest affinity for the FP-receptor (K(i) = 143 +/- 36 nM) and much lower affinity for DP-, EP(3)-, IP-, and TP-receptors, and for several nonprostanoid receptors, enzymes, neurotransmitter uptake sites, ion channels, and other regulatory sites. AL-12180 activated phospholipase C-mediated phosphoinositide hydrolysis (potency, EC(50) = 13.7-42.7 nM) through the FP-receptor in a variety of cells, such as h-CM, h-TM cells, human embryonic kidney cells expressing the cloned human ciliary body FP-receptor (HEK-FP), mouse 3T3 cells, and rat vascular smooth muscle cells. AL-8810, an FP-antagonist, blocked the effects of AL-12180 in h-CM cells (IC(50) = 8.7 microM). AL-12180 also stimulated the mobilization of intracellular Ca(2+) ([Ca(2+)](i)) in h-TM cells (EC(50) = 111 +/- 36 nM), h-CM cells (EC(50) = 11 nM), and in host cells expressing the cloned human ciliary body FP-receptor (EC(50) = 5.9 +/- 3.1 nM). AL-12180 lacked significant agonist activity at DP-, EP(2)-, EP(4)-, IP-, and TP-receptors in cell-based assays. However, AL-12180 contracted porcine central retinal and short posterior ciliary arteries in vitro with micromolar potencies that appeared to involve TP-receptor activation. in vivo, AL-12182 elicited dose-related hyperemia in the rabbit eye, miosis in the cat eye, and ocular hypotension in the nonhuman primate eye. CONCLUSIONS: AL-12180 is a relatively potent and selective FP-receptor agonist whose isopropyl ester prodrug (AL-12182) lowers IOP by as much as 40% following topical ocular dosing in a laser-induced nonhuman primate model of ocular hypertension.     

AL-34662: a potent, selective, and efficacious ocular hypotensive serotonin-2 receptor agonist.

PURPOSE AND METHODS: The aim of this study was to determine the ocular pharmacological characteristics of AL-34662 (1-((S)-2-aminopropyl)-1H-indazole-6-ol), a new synthetic serotonin-2 (5-HT2) receptor-agonist ocular hypotensive agent. A variety of well-documented in vitro and in vivo procedures were utilized to study the pharmacological attributes of AL-34662. RESULTS: AL-34662 exhibited a high affinity for the rat and human 5-HT2 receptor (IC50=0.8-1.5 nM) and for cloned human 5-HT2A-C receptors (IC50=3-14.5 nM). AL-34662 stimulated phosphoinositide turnover in human ciliary muscle (h-CM; EC50=289+/-80 nM) and in human trabecular meshwork (h-TM; EC50=254+/-50 nM) cells. AL-34662 also mobilized intracellular Ca2+ ([Ca2+]i) in h-CM (EC50=140+/-23 nM) and h-TM (EC50=38+/-8 nM) cells, being a full agonist like 5-HT itself. AL-34662's effects in the h-CM (and h-TM) cells were potently antagonized by 5-HT2A-antagonist M-100907 (IC50=1.8+/-0.7 nM), but weakly by 5-HT2B-antagonist (RS-127445 IC50>10 microM), 5-HT2B/C- antagonist (SB-242084 IC50=2.08 microM) and 5-HT2C antagonist (RS-102221 IC50>1 microM). AL-34662 caused relatively minimal ocular discomfort and hyperemia in rabbit and guinea pig eyes. It efficaciously lowered intraocular pressure (IOP) in the conscious ocular hypertensive monkey eyes (33% at 300 microg). The (R)-enantiomer (AL-34707) and the racemate (AL-34497) were less potent and/or efficacious than AL-34662 in all of these assays. CONCLUSIONS: AL-34662 is a high-affinity 5-HT2 receptor agonist that potently mobilizes [Ca2+]i in h-CM and h-TM cells, and which efficaciously lowers IOP in conscious ocular hypertensive cynomolgus monkey eyes through a local effect with minimal side-effects.     

Neuroprotective effects of prostaglandin analogues on retinal ganglion cell death independent of intraocular pressure reduction

Prostaglandin (PG) analogues may have an additional effect to protect neurons independent of IOP reduction. Only a few reports indicated that some PG analogues had neuroprotective effects or increased blood flow in in vivo and in vitro models. However, there is no comparative study using all clinically available PG analogues and also using primary culture of retinal ganglion cell (RGC). Our purpose of study is to investigate the direct neuroprotective effect of PG analogues on glutamate- and hypoxia-induced RGC death using rat purified primary RGC culture with latanoprost acid, travoprost acid, bimatoprost acid, bimatoprost, tafluprost acid, unoprostone, and PGF2α. Purified RGCs cultures were obtained from retinas of 6 days old Wistar rats, following a two-step immuno-panning procedure. After 72 h of cultivation, the neuroprotective effect of PG analogues (1 nM, 10 nM and 100 nM) was investigated by culturing the RGCs in 25 μM glutamate for a further 72 h or 5% O2 hypoxic condition for 24 h. The RGC viability under each condition normalized to that under normal condition without stress was evaluated as live cell percentage based on a total of 15 repeated experiments. As a result, 100 nM of latanoprost acid, tafluprost acid, bimatoprost acid, and bimatoprost significantly increased RGC survival rate by suppressing apoptosis. PG analogues indicated IOP independent neuroprotective effect on glutamate- or hypoxia-induced RGC death using rat primary RGC culture at clinically available intracameral concentration. Since those profiles were different from clinical efficacy in IOP reduction, the mechanism of neuroprotection may be not related to FP receptor stimulation.     

Evidence for the involvement of cannabinoid CB1 receptors in the bimatoprost-induced contractions on the human isolated ciliary muscle

PURPOSE: To evaluate the bimatoprost effects in the isolated human ciliary muscle and to assess how these response can be modulated by AL8810 and SR141716A. METHODS: In a myograph system (isometric force measurement), ciliary muscles were exposed cumulatively to PGF(2alpha), latanoprost, travoprost, bimatoprost, and anandamide (0.1 nM-10 microM). Experiments were also conducted in the presence of AL8810 (FP receptor antagonist; 100 nM) or SR141716A (CB(1) receptor antagonist; 10-100 nM). Contractions were expressed as the percentage of 10 microM carbachol-induced contractions. RESULTS: In quiescent tissues, concentration-response curves for bimatoprost, anandamide, PGF(2alpha,) latanoprost, and travoprost were constructed. Bimatoprost showed an important contractile effect on isolated human ciliary muscle strips (E(max) = 125% +/- 0.09%); the maximal effect was higher than that obtained with carbachol. Contractions were inhibited by SR141716A (10 and 100 nM) and AL8810 (100 nM). CONCLUSIONS: This study showed evidence of direct interaction of bimatoprost with the contractility of the human ciliary muscle through interaction with cannabinoid CB(1) receptor and prostanoid FP receptors.     

Effects of prostaglandin F2alpha, latanoprost and carbachol on phosphoinositide turnover, MAP kinases, myosin light chain phosphorylation and contraction and functional existence and expression of FP receptors in bovine iris sphincter

A potential role for myosin light chain kinase (MLCK) in regulating intraocular pressure and outflow function has recently been reported in living monkey eye and rabbit eye. There is little information about the effects of the ocular hypotensive agents, prostaglandin F2alpha (PGF2alpha) and latanoprost on this signaling pathway in ocular tissues. The aim of this study was to determine the agonist activity of PGF2alpha, latanoprost and carbachol (CCh) on the MLCK pathway in isolated bovine iris sphincter and furthermore to investigate the existence of the FP receptor in this tissue. In the present studies on the MLCK pathway four signal transduction mechanism assays were employed, phosphoinositide (PI) turnover, p42/p44 MAP kinase phosphorylation and activation, MLC phosphorylation and contraction. In the studies on the existence of the FP receptor in the bovine iris sphincter, the pharmacology and expression of the FP receptor protein, using a polyclonal anti-FP-receptor antibody and Western blot analysis, were determined. The data obtained on the MLCK pathway showed that the three agonists stimulated the biochemical and pharmacological responses in a concentration and time-dependent manner and that the order of potency and efficacy is PGF2alpha>latanoprost>CCh. The EC50 values in the PI turnover, MAP kinase phosphorylation, MLC phosphorylation and contraction assays were for PGF2alpha: 9, 42, 200 and 140 nM, respectively, for latanoprost: 13, 59, 250 and 828 nM, respectively, and for CCh: 22, 200, 630 and 910 nM, respectively. Wortmannin, a selective inhibitor of MLCK, dose-dependently inhibited MLC phosphorylation and contraction induced by PGF2alpha, demonstrating a close relationship between activation of the MLCK pathway and contraction. The pharmacological studies showed that in the concentration range of 1 nM to 10 microM, the FP-receptor agonists caused concentration-response curves with the following order of potencies: 17-phenyl trinor PGF2alpha (bimatoprost acid)>PGF2alpha>cloprostenol>latanoprost>latanoprost acid>bimatoprost amide>fluprostenol. Immunoblot analysis of the FP receptor demonstrated expression of the prostaglandin FP receptor protein in this smooth muscle. These results clearly indicate that the MLCK signaling pathway is involved in the FP-receptor function of the bovine iris sphincter and furthermore demonstrate that functional FP receptors exist and are expressed in this tissue.     

The effects of prostaglandin analogues on IOP in prostanoid FP-receptor-deficient mice

PURPOSE: This study was designed to clarify the involvement of the prostanoid FP receptor in the intraocular pressure (IOP)-lowering effects of latanoprost, travoprost, bimatoprost, and unoprostone with the use of FP-receptor-deficient (FPKO) mice. METHODS: FPKO and wild-type (WT) mice were bred and acclimatized under a 12-hour light-dark cycle. IOP was measured under general anesthesia by a microneedle METHOD: To evaluate the effects of each drug, a single drop (3 muL) of each drug solution was topically applied in a masked manner to a randomly selected eye. IOP reduction was evaluated by the difference in IOP between the treated eye and the untreated contralateral eye in the same mouse. First, the diurnal variation and baseline IOP in WT and FPKO mice were measured. Then, to determine the window feasible for demonstrating the most marked ocular hypotensive effect, 0.005% latanoprost was applied to WT mice during the day or at night. The time when the ocular hypotensive effect was larger was selected for further studies to evaluate the effects of latanoprost (0.005%), travoprost (0.004%), bimatoprost (0.03%), and unoprostone (0.12%). In addition, bunazosin (0.1%) was also applied to demonstrate functional uveoscleral outflow in FPKO mice. All experiments were conducted under a masked study design. RESULTS: The baseline IOP (mean +/- SEM) in WT and FPKO mice was 15.0 +/- 0.2 and 15.0 +/- 0.3 mm Hg, respectively, during the day, and 18.9 +/- 0.4 and 19.2 +/- 0.4 mm Hg, respectively, at night. In WT mice, latanoprost significantly lowered IOP both during the day and at night, at 2 to 6 hours and 1 to 6 hours after application, respectively. Maximal IOP reduction was observed at 3 hours after drug instillation both during the day (10.9 +/- 1.8%) and at night (23.2 +/- 1.1%). At 3 hours after instillation, latanoprost (10.9 +/- 1.8% and 23.2 +/- 1.1%, daytime and nighttime, respectively), travoprost (15.9 +/- 1.4% and 26.1 +/- 1.2%) and bimatoprost (8.8 +/- 2.0 and 19.8 +/- 1.5%) significantly lowered IOP in WT mice both during the day and at night; isopropyl unoprostone significantly lowered IOP at night (13.7 +/- 1.9%) but not during the day (5.3 +/- 3.2%). In FPKO mice, latanoprost, travoprost, bimatoprost, and unoprostone showed no significant IOP-lowering effect. Bunazosin significantly lowered IOP in both WT (22.1 +/- 1.6%) and FPKO mice (22.2 +/- 2.1%). CONCLUSIONS: A single application of latanoprost, travoprost, bimatoprost, or unoprostone had no effect on IOP in FPKO mice with presumed functional uveoscleral outflow pathways. The prostanoid FP receptor plays a crucial role in the mechanism of early IOP lowering of all commercially available prostaglandin analogues.     

Prostaglandin analogues and mouse intraocular pressure: effects of tafluprost, latanoprost, travoprost, and unoprostone, considering 24-hour variation

PURPOSE: To establish a mouse model for the pharmacological analysis of antiglaucoma drugs, considering the effect of variations in IOP during 24 hours on the drugs' effects, and to evaluate the effect of a newly developed FP agonist, tafluprost, on mouse IOP, in comparison with three clinically available prostaglandin (PG) analogues. METHODS: Inbred adult ddY mice were bred and acclimatized under a 12-hour light-dark cycle. With mice under general anesthesia, a microneedle method was used to measure IOP. A single drop of 3 muL of either drug or vehicle solution was topically applied once into one eye in each mouse, in a blinded manner, with the contralateral, untreated eye serving as the control. IOP reduction was evaluated by the difference in IOP between the treated and untreated eyes in the same mouse. First, to determine the period feasible for demonstrating a larger magnitude of ocular hypotensive effect, the 24-hour diurnal variation in mouse IOP was measured, and 0.005% latanoprost was applied at the peak or trough time of variation in 24-hour IOP. The time point of the most hypotensive effect was selected for further studies, to evaluate the effects of PG analogues. Second, mice received tafluprost (0.0003%, 0.0015%, 0.005%, or 0.015%), latanoprost (0.001%, 0.0025%, or 0.005%), travoprost (0.001%, 0.002%, or 0.004%), or isopropyl unoprostone (0.03%, 0.06%, or 0.12%), and each corresponding vehicle solution. IOP was then measured at 1, 2, 3, 6, 9, and 12 hours after drug administration. The ocular hypotensive effects of the other three PG analogues were compared with that of tafluprost. All experiments were conducted in a masked study design. RESULTS: The IOP in the untreated mouse eye was higher at night than during the day. Latanoprost significantly lowered IOP at night (21.4%), compared with the IOP in the untreated contralateral eye 2 hours after administration. The maximum IOP reduction was 20.2% +/- 2.0%, 18.7% +/- 2.5%, and 11.2% +/- 1.8% of that in the untreated eye 2 hours after administration of 0.005% tafluprost, 0.005% latanoprost, and 0.12% isopropyl unoprostone, respectively, whereas it was 20.8% +/- 4.6% at 6 hours with 0.004% travoprost (n = 7 approximately 17). The order of ocular hypotensive effects of three clinically used PG analogues in mice was comparable to that in humans. Area under the curve (AUC) analysis revealed dose-dependent IOP reductions for each PG analogue. Tafluprost 0.005% decreased IOP more than 0.005% latanoprost at 3, 6, and 9 hours (P = 0.001-0.027) or 0.12% unoprostone at 2, 3, and 6 hours (P = 0.0004-0.01). CONCLUSIONS: The 24-hour variation in mouse eyes should be taken into consideration when evaluating the reduction of IOP. The mouse model was found to be useful in evaluating the pharmacological response to PG analogues. A newly developed FP agonist, 0.005% tafluprost, lowered normal mouse IOP more effectively than did 0.005% latanoprost.     

Adverse periocular reactions to five types of prostaglandin analogs

Purpose

We investigated the appearance frequency of eyelid pigmentation and eyelash bristles after the use of five types of prostaglandin (PG) analogs.

Methods

This study included 250 eyes from 250 patients diagnosed with primary open-angle glaucoma or ocular hypertension who were treated with either latanoprost, travoprost, tafluprost, bimatoprost, or isopropyl unoprostone for >3 months in only one eye. Photographs of both eyes were obtained, and the images were assessed by three ophthalmologists who were masked to treatment type. The existence of eyelid pigmentation and eyelash bristles was judged, and images of the left and right eyes were compared. Subjective symptoms regarding the existence of eyelid pigmentation and eyelash bristles were investigated through a questionnaire.

Results

There was no significant difference between the five types of medications with regard to eyelid pigmentation (P=0.537). Use of isopropyl unoprostone resulted in a significantly lower incidence of eyelash bristles (P<0.0001). The questionnaire investigation showed that eyelid pigmentation and eyelash bristles were significantly more frequent with travoprost (42.0% and 42.0%, respectively) and bimatoprost (58.0% and 60.0%, respectively) than with other three medications (P<0.0001).

Conclusion

The appearance frequency of eyelid pigmentation was similar among the five types of PG analogs studied, and eyelash bristles appeared less frequently with isopropyl unoprostone use. Patients are conscious of eyelash bristles; therefore, these adverse effects should be sufficiently explained to patients before PG administration.     

Travoprost compared with other prostaglandin analogues or timolol in patients with open-angle glaucoma or ocular hypertension: meta-analysis of randomized controlled trials

BACKGROUND: It is still uncertain whether travoprost has comparable or better efficacy compared with other prostaglandin analogues or timolol in patients with open-angle glaucoma or ocular hypertension. The authors performed a meta-analysis of randomized controlled trials to evaluate the incidence of reported side-effects and intraocular pressure (IOP)-lowering effect of travoprost versus other prostaglandin analogues (latanaprost, bimatoprost, unoprostone) or timolol. METHODS: Systematic literature retrieval was conducted in Pubmed, EMBASE, Chinese Bio-medicine Database and Cochrane Controlled Trials Register to identify the potentially relevant randomized controlled trials. The statistical analysis was performed by RevMan 4.1 software that was provided by the Cochrane Collaboration. The outcome measures were the incidence of reported side-effects (hyperaemia, iris pigmentation, eyelash changes) and mean IOP pooled over treatment visits. RESULTS: In total, 12 articles involving 3048 patients with open-angle glaucoma or ocular hypertension were included in this meta-analysis. The combined results showed that travoprost 0.004% was more effective than timolol or travoprost 0.0015% in lowering IOP, but not more effective than bimatoprost or latanoprost. Travoprost 0.004% caused a higher percentage of hyperaemia than timolol, latanoprost, or travoprost 0.0015%. There was an increased incidence of pigmentation with travoprost than timolol. Travoprost 0.004% caused a higher percentage of eyelash changes than timolol, latanoprost, or travoprost 0.0015%. CONCLUSION: According to data available, travoprost is more effective than timolol in lowering IOP in patients with open-angle glaucoma or ocular hypertension. Compared with other prostaglandin analogues, travoprost appears to be equivalent to bimatoprost and latanoprost. Although a limited number of local side-effects were reported, no serious treatment-related side-effects were reported.     

Vasoactive responses of U46619, PGF2alpha, latanoprost, and travoprost in isolated porcine ciliary arteries

PURPOSE: To compare the vasoactive properties of the prostanoids U46619 (thromboxane A2 analogue), prostaglandin F(2alpha) (PGF(2alpha)), latanoprost free acid, and travoprost free acid in isolated porcine ciliary arteries. METHODS: In a myograph system (isometric force measurement), quiescent vessels were exposed (cumulatively) to U46619, PGF(2alpha), latanoprost, or travoprost (0.1 nM-0.1 mM). Experiments were also conducted in the presence of SQ 29548 (TP-receptor antagonist; 3-10 microM) or AL-8810 (FP-receptor antagonist; 3-30 microM). Contractions were expressed as the percentage of 100 mM potassium chloride-induced contractions. RESULTS: In quiescent vessels, contractions (concentration-response curves) induced by (0.1 mM) PGF(2alpha) (87.9% +/- 3.5%), U46619 (66.7% +/- 4.1%), and latanoprost (62.9% +/- 3.6%) were more pronounced (P < or = 0.001) than those induced by travoprost (23.0% +/- 4.4%). Concentration-response curves for PGF(2alpha), latanoprost, and travoprost were preceded by a smaller contraction peak (0.1 microM) that was higher (P < or = 0.05) for travoprost (24.4% +/- 2.8%) than for PGF(2alpha) (12.9% +/- 4.6%), but not different (P = 0.58) from latanoprost (22.0% +/- 3.0%). The 50% maximal contraction (PD50: negative log M concentration) of U46619 (-8.05 +/- 0.13) was lower (P < or = 0.001) than those of latanoprost (-5.65 +/- 0.10), PGF(2alpha) (-5.49 +/- 0.14), and travoprost (-5.12 +/- 0.52). Contractions were inhibited (P < or = 0.05-0.001) either by SQ 29548 or AL-8810. CONCLUSIONS: In isolated porcine ciliary arteries, all prostanoids tested induced contractions. Among them, travoprost appeared to be the least potent and U46619 the most efficient.     

Conjunctival hyperemia in healthy subjects after short-term dosing with latanoprost,bimatoprost, and travoprost

PURPOSE: To evaluate conjunctival hyperemia after short-term use of latanoprost 0.005%, bimatoprost 0.03% and travoprost 0.004% in normal adults. DESIGN: Prospective, randomized, double-masked crossover active controlled comparison. METHODS: We evaluated conjunctival hyperemia by a standard photographic measure at the slit lamp and by anterior segment photographs in healthy subjects after dosing for 5 days with latanoprost, bimatoprost, or travoprost. Conjunctival hyperemia was evaluated at 24-hour trough (hour 0) and at hour 1 after dosing. Each subject was crossed over between periods after a 1-week washout interval. RESULTS: Twenty-eight subjects (mean age 26 +/- 9 years) completed this study. Several comparisons were noted to be significant between groups by slit-lamp biomicroscopy: first, at hour 0 latanoprost had significantly less hyperemia than bimatoprost; second, at hour 0 latanoprost showed significantly less change than bimatoprost compared with the study baseline (visit 2); third, at hour 1 latanoprost had significantly less hyperemia than travoprost; fourth, at hour 1 latanoprost demonstrated significantly less change from baseline in hyperemia than travoprost (visit 2); fifth, at hour 1 latanoprost had less change in hyperemia than bimatoprost or travoprost between the study and the nonstudy eye (P = .03); and last, at hour 1 latanoprost showed significantly less change than bimatoprost and travoprost compared with hour 0 (P = .04). Additionally, similar grades were observed by photographs with latanoprost demonstrating the lowest levels of hyperemia. Subjects complained less about other people noticing their red eye with latanoprost than bimatoprost or travoprost (P = .048). No serious adverse events were noted. CONCLUSIONS: This study suggests that latanoprost may cause significantly less short-term conjunctival hyperemia on average than bimatoprost or travoprost in healthy subjects.     

Corneal punctate staining with latanoprost, bimatoprost, and travoprost in healthy subjects

PURPOSE: To evaluate short-term conjunctival and corneal punctate staining with latanoprost, bimatoprost, and travoprost in healthy individuals. MATERIALS AND METHODS: A single centered, active-controlled, three-period crossover comparison that evaluated conjunctival and corneal punctate staining, by grade and individual stains, in healthy subjects after dosing for five days in one eye with latanoprost, bimatoprost, or travoprost. Staining was evaluated at 24-hour trough (Hour 0) and at Hour 1 after dosing. RESULTS: Twenty-eight subjects completed this study. This study found that there was no significant difference by ANOVA for the number of individual corneal punctate stains either at trough (latanoprost 22.6 +/- 25.4, bimatoprost 16.8 +/- 25.6, and travoprost 21.1 +/- 26.0 mm Hg) (P = 0.33) or at 1 hour after dosing (latanoprost 23.8 +/- 26.3 bimatoprost 18.2 +/- 25.2, and travoprost 26.1 +/- 26.1 mm Hg) (P = 0.75) among treatment groups. No significant differences existed among treatment groups in the study eye compared with the non-study eye or to the study eye at Hour 0 or Hour 1 or to the period initiation or baseline visits (P > 0.05). Several significantly different comparisons, inconsistent in nature, were observed for the nasal and temporal conjunctival staining between the treatment groups. There were no differences in unsolicited or solicited adverse events between groups. CONCLUSION: This study suggests that, in healthy subjects after short-term treatment, latanoprost, bimatoprost, and travoprost demonstrate generally similar ocular surface epithelial staining characteristics.