Prostanoids in the therapy of glaucoma

Effect of travoprost, latanoprost and bimatoprost PGF2α treatments on the biomechanical properties of in-vivo rabbit cornea

Prostaglandin F2α analogues (PGF2α), one of the most commonly prescribed classes of hypotensive agents, could decrease collagen fibril density and remodel the extracellular matrix in cornea. We hypothesized that PGF2α's would induce corneal softening, reduce the accuracy of intraocular pressure (IOP) measurement and lead to uncertainty in the effectiveness of the therapy. We determined the stress-strain behavior of rabbit cornea after PGF2α usage and evaluated the effect of biomechanical changes associated with PGF2α treatment on IOP measurements by Goldmann Applanation Tonometry (GAT). The tangent modulus decreased after PGF2α treatment, while the stromal interfibrillar spacing increased. PGF2α was shown to also affect the lateral eye with lower effect, which did not undergo direct eyedrop treatment. Significant decreases in the numerical predictions of GAT-IOP were predicted in all treated groups relative to control groups. Different PGF2α's (travoprost, latanoprost and bimatoprost) were associated with different extents of reduction in tissue stiffness and changes in corneal microstructure. PGF2α-induced changes in corneal mechanical properties could reduce the accuracy of IOP measurement and may cause an overestimation of the effect of PGF2α in lowering IOP, possibly leading to uncertainties in glaucoma management.

Biomechanical Effects of Two Forms of PGF2α on Ex-vivo Rabbit Cornea

PURPOSE

To investigate the biomechanical effects of two synthetic prostaglandin F2α analogues (PGF2α), namely Travoprost and Tafluprost, on the ex-vivo rabbit cornea.

MATERIALS AND METHODS

Ninety-six eyes of 48 Japanese white rabbits were divided into 3 equal groups randomly; the Travoprost treated group (Tra), the Tafluprost treated group (Taf) and the control group (Co). Eyes in Tra and Taf groups were preserved in storage medium for 10 days with 1:10 Travoprost and Tafluprost diluents, respectively; while the Co eyes were preserved in a similar but PGF2α-free medium. Twenty-four corneas of each group were tested under inflation conditions with up to 30 mmHg posterior pressure. The pressure-deformation data obtained experimentally were used in an inverse analysis process to derive the stress-strain behavior of the tissue, using which the tangent modulus, a direct measure of the tissue's material stiffness, was calculated. The remaining eight specimens of each group were analyzed using electron microscopy for fibril diameter and interfibrillar spacing.

RESULTS

Although the central corneal thickness increased significantly in the three groups after storage (p < .01), it was similar in all groups both before (p = .598) and after storage (p = .181). After treatment with Travoprost and Tafluprost, the corneas exhibited lower tangent modulus (by 29.2% and 29.8%, respectively, at 6 kPa stress) and larger stromal interfibril spacing (by 21.9% and 23.6%) compared with the control group. There was no significant change in fibril diameter with either Travoprost or Tafluprost treatment (p = .769).

CONCLUSIONS

The results demonstrated significant reductions in tangent modulus and increases in interfibrillar spacing, which were of similar magnitudes, with the application of two different forms of PGF2α.

Rebaudioside A/TPGS mixed nanomicelles as promising nanocarriers for nimodipine ocular delivery

Nimodipine (NMD), a calcium channel blocker, has demonstrated benefits in treating glaucoma. However, its ocular therapeutic application remains limited due to its poor aqueous solubility, which restrains the development of an ophthalmic formulation. Thus, the present study aimed to formulate an NMD micelle ophthalmic solution to enhance the potential of NMD in an ocular topical formulation to treat glaucoma. The NMD micelle ophthalmic solution was formulated with nanocarriers composed of rebaudioside A and D-α-tocopheryl polyethylene glycol 1000 succinate. Spherical mixed micelles were optimized and obtained at a small micelle size 13.429 ± 0.181 nm with a narrow size distribution (polydispersity index 0.166 ± 0.023) and high encapsulation efficiency rate (99.59 ± 0.09%). Compared with free NMD, NMD in micelles had much greater in vitro membrane permeability and antioxidant activity. The NMD micelle ophthalmic solution was well tolerated in rabbit eyes. It profoundly improved the in vivo intraocular permeation of NMD, and in vivo intraocular pressure reduction and improved miosis were also observed. Accordingly, this NMD micelle ophthalmic solution might be a promising ocular formulation to treat glaucoma. Graphical abstract.

Effects of pre-surgical administration of prostaglandin analogs on the outcome of trabeculectomy

For primary open angle glaucoma (POAG), laser treatment or surgery is used when the target intraocular pressure (IOP) cannot be achieved by pharmacological agents, such as prostaglandin (PG) analogs; these drugs also have varied effects. We retrospectively reviewed the medical records of 74 POAG patients (74 eyes) whose IOP was inadequately controlled by PG analogs (bimatoprost [13 eyes], latanoprost [34 eyes], tafluprost [11 eyes], and travoprost [16 eyes]) and underwent primary trabeculectomy. The proportion of patients with no recurrent IOP elevation within 24 months post-trabeculectomy was significantly (P < 0.001) lower in the bimatoprost group (31.3%) than in the latanoprost (83.2%), tafluprost (45.5%), or travoprost groups (65.6%). Deepening of the upper eyelid sulcus (DUES) was observed before trabeculectomy in 18 of 74 eyes (24.3%) treated with bimatoprost (9 eyes; 50.0%), latanoprost (3 eyes; 16.7%), tafluprost (1 eye; 5.5%) and travoprost (5 eyes; 27.8%). The proportion of patients with no recurrent IOP elevation up to 24 months post-trabeculectomy was significantly (P < 0.0001) lower in the DUES(+) group (34.7%) than in the DUES(-) group (74.3%). Multivariate stepwise logistic regression analysis, with no recurrent IOP elevation used as dependent variable, and bimatoprost, latanoprost, travoprost, tafluprost, β-blocker, carbonic anhydrase inhibitor, brimonidine, gender, age, preoperative IOP, mean deviation, duration of PG analog use before surgery, and the number of ophthalmic solutions used as independent variables, identified only bimatoprost as a significant independent factor (P = 0.0368). Thus, the outcome of trabeculectomy varied depending on the PG analog used preoperatively, and bimatoprost use was associated with a high risk of recurrent IOP elevation up to 2 years post-trabeculectomy. This may indicate that the incidence of DUES differed with the PG analog used. Patients with glaucoma who are treated with bimatoprost should be monitored for DUES, and when these patients undergo trabeculectomy, the postoperative course of IOP should be followed carefully.

Fluorination methods in drug discovery

Fluorination reactions of medicinal and biologically-active compounds will be discussed. Late stage fluorination strategies of medicinal targets have recently attracted considerable attention on account of the influence that a fluorine atom can impart to targets of medicinal importance, such as modulation of lipophilicity, electronegativity, basicity and bioavailability, the latter as a consequence of membrane permeability. Therefore, the recourse to late-stage fluorine substitution on compounds with already known and relevant biological activity can provide the pharmaceutical industry with new leads with improved medicinal properties. The fluorination strategies will take into account different fluorinating reagents, either of nucleophilic or electrophilic, and of radical nature. Diverse families of organic compounds such as (hetero)aromatic rings, and aliphatic substrates (sp(3), sp(2), and sp carbon atoms) will be studied in late-stage fluorination reaction strategies.

Bimatoprost, latanoprost, and tafluprost induce differential expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases

Background

Differences in the increase in matrix metalloproteinase (MMP) and decrease in tissue inhibitor of metalloproteinase (TIMP) activity may contribute to the different characteristics observed clinically on decreased intraocular pressure in patients with glaucoma or ocular hypertension. The purpose of this study was to investigate differences in the expression profiles of MMPs and TIMPs induced by the prostaglandin analogs bimatoprost, latanoprost, and tafluprost in human non-pigmented ciliary epithelial cells (HNPCECs).

Methods

HNPCECs were cultured for 24 h with 0, 10, 100, or 1000 μM of the free acid forms of bimatoprost, latanoprost, and tafluprost. We measured the expression levels of MMPs and TIMPs using real-time polymerase chain reaction, and compared the results. Enzyme activities of MMP-2 and −9 in conditioned media were measured by gelatin zymography.

Results

All prostaglandin analogs we examined dose-dependently increased expression levels of MMP-1, −2, −3, −9, and −17, whereas expression levels of TIMP-1 and −2 decreased with increasing concentrations of each analog. Each prostaglandin analog induced different levels of increases in MMPs and decreases in TIMPs.

Conclusions

Unique expression profiles of MMPs and TIMPs induced by bimatoprost, latanoprost, and tafluprost, as shown in HNPCECs, may contribute to clinically different effects on intraocular pressure decreases in patients with glaucoma or ocular hypertension.

EP3/FP dual receptor agonist ONO-9054 administered morning or evening to patients with open-angle glaucoma or ocular hypertension: results of a randomised crossover study

Background/aims

The novel prostaglandin E (EP) 3 and prostaglandin F (FP) receptor agonist ONO-9054 is effective in lowering intraocular pressure (IOP) in patients with ocular hypertension and open-angle glaucoma when administered once daily. This study compares the effects of morning (AM) versus evening (PM) dosing of ONO-9054 on tolerability and IOP lowering.

Methods

This was a single-centre, randomised, double-masked, two-sequence, placebo-controlled crossover study in 12 subjects with bilateral primary open-angle glaucoma or ocular hypertension. Two 14-day crossover regimens were separated by a 2-week washout: ONO-9054 (1 drop to each eye) in the morning (07:00) and vehicle in the evening (19:00) and vice versa. IOP was measured multiple times during select days. Ocular examinations also evaluated safety and tolerability.

Results

Mild ocular hyperaemia, reported by six subjects with PM dosing, was the most frequent adverse event. Mild to moderate dryness was also slightly more frequent after PM dosing. Maximum IOP reduction from baseline occurred on day 2 with decreases from baseline of −7.4 mm Hg (−30.8%) for AM dosing and −9.1 mm Hg, (−38.0%) for PM dosing; after 14 days, mean reduction in IOP was −6.8 mm Hg (−28.6%) for AM dosing and −7.5 mm Hg (−31.0%) for PM dosing.

Conclusions

PM dosing of ONO-0954 was associated with a slightly increased frequency of mild hyperaemia and mild to moderate dryness. Both dosing schedules provided sustained reduction in IOP.

Trial registration number

NCT01670266.

Intraocular pressure-lowering efficacy and safety of bimatoprost 0.03% therapy for primary open-angle glaucoma and ocular hypertension patients in China

BACKGROUND

To report the clinical outcomes in Chinese patients with primary open-angle glaucoma and ocular hypertension treated with bimatoprost 0.03% therapy.

METHODS

Two hundred sixty-three Chinese patients with primary open-angle glaucoma and ocular hypertension who needed initial or additional intraocular pressure (IOP) lowering were recruited in this prospective, open-label, multicenter clinical study and were treated with bimatoprost 0.03%. Patients received bimatoprost 0.03% as initial, replacement or adjunctive IOP-lowering therapy, and follow-up visits were performed at week 1, and month 1 and 3 of the bimatoprost treatment. The efficacy outcome measure was the post-treatment IOP level. The safety outcome measures included the rate of medication-related symptoms, physical signs, reported adverse events, and the level of conjunctival hyperemia.

RESULTS

Among 240 patients who could be categorized by pre-existing therapies and the bimatoprost therapy regimen in the study, IOP values observed in all medication conditions showed significant IOP reduction at all study visits compared with baseline. At 3 months, 8.0 ± 3.7 mmHg (32.0%) reduction in IOP was observed in treatment-naive patients after bimatoprost monotherapy; in the patients previously on various therapy regimens, 1.9 ± 2.8 mmHg (9.5%) to 6.4 ± 6.1 mmHg (24.8%) additional IOP lowering was achieved after switching to bimatoprost monotherapy or bimatoprost combination therapy. The most common adverse event was conjunctival hyperemia, mainly of trace and mild intensity.

CONCLUSIONS

Our results show that bimatoprost 0.03% was effective in lowering IOP with favorable safety in Chinese primary open-angle glaucoma and ocular hypertension patients.

IOP-lowering effect of isoquinoline-5-sulfonamide compounds in ocular normotensive monkeys

Rho-associated coiled coil-formed protein kinase (ROCK) inhibitors are under development as a new class of antiglaucoma agents. Based on the potent ROCK inhibitor H-1152, previously developed by us, we explored the possibility of related compounds as antiglaucoma agents and synthesized seven types of H-1152-inspired isoquinoline-5-sulfonamide compounds (H-0103-H-0107, H-1001, H-1005). Although all of these compounds potently inhibited ROCK (IC50=18-48 nM), only H-0104 and H-0106 exerted strong intraocular pressure (IOP)-lowering effects into the eyes of monkeys. These results suggested the possibility that there is no direct relationship between ROCK inhibition and IOP-lowering effects, indicating that the initial screening of compounds based on ROCK inhibitory activity may be an unsuitable strategy for developing antiglaucoma agents with potent IOP-lowering effects.

Evaluation of eye drop administration technique in patients with glaucoma or ocular hypertension

OBJECTIVE

To evaluate eye drop administration by patients at multiple visits in the setting of a randomized controlled trial.

STUDY DESIGN AND METHODS

Patients with glaucoma or ocular hypertension were randomized to 12 weeks of treatment with topical ocular hypotensive medication in a multicenter, investigator-masked trial. At baseline, patients were given a questionnaire for self-assessment of difficulty with drop administration. At baseline and 12 weeks, patients demonstrated drop instillation using a bottle of artificial tears.

MAIN OUTCOME MEASURES

Patient self-assessment of difficulty with drop administration and observed patient difficulty with drop administration, defined as bottle touching eye/adnexa, drop missing the ocular surface, or administering more than 1 drop.

RESULTS

Of 164 enrolled patients, 50% had previously been treated with ocular hypotensive medication for ≥3 years. Only 11.4% of patients reported difficulty with eye drop administration at study entry. At baseline, 18.2% of patients touched their eye/adnexa with the bottle and 10.3% missed the eye. At 12 weeks, 18.5% and 8.6% of patients, respectively, had similar difficulties. Overall, difficulty with drop instillation was observed in 42.1% of patients. Difficulty at both visits was seen in 35.3% of patients who reported difficulty at entry and in 17.2% of patients who denied difficulty. The relative risk of demonstrating difficulty at either visit was 2.0 times greater for patients who self-reported difficulty at study entry (P = 0.004). The relative risk of demonstrating difficulty at week 12 was 3.8 times greater for patients with observed difficulty at baseline (P < 0.001). Limitations of the study design included self-administration of drops to the eye of the patient's choice and observation in an office setting.

CONCLUSIONS

Patients with experience instilling topical glaucoma medications continue to have difficulties with eye drop administration, including patients who do not self-report difficulty. The risk of difficulty with eye drop administration is increased in patients who self-report difficulty and in patients who have been previously observed to have difficulty.

CLINICAL TRIAL REGISTRY NUMBER

NCT01253902.

Clinical options for the reduction of elevated intraocular pressure

Elevated IOP in clinical practice is usually seen in glaucoma or ocular hypertension. Glaucoma affects 60 million people worldwide and 8.4 million are bilaterally blind from this chronic disease.1 Options for reducing IOP rely on pharmacological agents, laser treatments and surgery which may be penetrating or non-penetrating. The last twenty years has seen significant changes in all of these strategies. This review aims to cover these clinical options and introduce some of the new technologies currently in development for the clinical lowering of IOP.

A prospective study evaluating IOP changes after switching from a therapy with prostaglandin eye drops containing preservatives to nonpreserved tafluprost in glaucoma patients

Purpose. To compare the ocular hypotensive effect of tafluprost with prostaglandin analogues (PGAs) in glaucoma patients. Methods. 89 primary open-angle glaucoma patients treated with bimatoprost, latanoprost, or travoprost for at least 3 months complaining for ocular discomfort were switched to tafluprost. IOP was assessed at baseline and 3 months after switching the therapy by daily curve. Primary outcome was to compare the mean daily IOP of tafluprost with PGAs. Results. The mean daily IOP was 16 ± 2.1 and 16.6 ± 2.0 mm Hg at baseline and after switching to tafluprost, respectively (P > 0.05). When analysis was carried out between tafluprost and each previous PGAs, the comparison between latanoprost and tafluprost and travoprost and tafluprost did not show any statistically significant difference in mean daily IOP and at each time point. The comparison between bimatoprost and tafluprost showed a statistically significant difference in mean daily IOP (P < 0.05) and at each time point (P < 0.05). Conclusions. After 3 months of switching tafluprost showed an overall IOP lowering effect similar to others PGAs. When each PGA was compared with tafluprost, bimatoprost showed to provide a statistically significant additional IOP lowering effect.

In vitro study of antiadipogenic profile of latanoprost, travoprost, bimatoprost, and tafluprost in human orbital preadiopocytes

PURPOSE

To investigate the effect of prostaglandin F2α (PGF2α), latanoprost, travoprost, bimatoprost, and tafluprost on human orbital preadipocyte differentiation and intracellular lipid storage, and to reveal the potential mechanisms by which topical prostaglandin analogs induce orbital fat volume reduction and cause deep superior sulcus syndrome.

METHODS

Human orbital adipose precursors were treated in vitro for 24 h (day 1) with PGF2α, latanoprost, travoprost, bimatoprost, and tafluprost in their commercial formulations (1:100 dilution). Expressions of adipogenic transcription factor, peroxisome proliferator-activated receptor-gamma (PPARγ), and CCAAT-enhancer-binding protein α (C/EBPα) were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) at day 7. At 14 days, cells were stained with oil red O, intracellular lipid accumulation was evaluated by lipid absorbance, and adipocyte expression marker [Lipoprotein lipase (LPL)] was determined by real-time RT-PCR.

RESULTS

Our results showed that PGF2α and topical prostaglandin analogs down-regulated the expression of PPARγ and C/EBPα, and inhibited accumulation of intra-cytoplasmic lipid droplets and expression of LPL compared with the untreated control. Comparison between the 4 drugs showed that latanoprost had the weakest antiadipogenic effect, and bimatoprost induced the most significant reduction of adipogenesis.

CONCLUSION

Latanoprost, travoprost, bimatoprost, and tafluprost inhibited human preadipocyte differentiation and intracellular lipid accumulation. Morphologic and metabolic changes in orbital adipocytes caused by PGF2α analogs are a possible pathophysiologic explanation of superior eyelid deepening in patients with glaucoma.

Tafluprost for the reduction of interocular pressure in open angle glaucoma and ocular hypertension

Tafluprost is an FP receptor antagonist that has been shown in clinical studies in Europe and Japan to be extremely useful in treating elevated intraocular pressure and glaucoma. The drug is well tolerated and appears to be at least equal in effectiveness and perhaps superior to other protanoids for routine use comparison to be superior to other treatments for the elevated IOP as the side effects and other related symptomology appear to be less, while maintaining a level of pressure control for prolonged periods.

Safety and tolerability of tafluprost in treatment of elevated intraocular pressure in open-angle glaucoma and ocular hypertension

Glaucoma is one of the most common neuropathies of the optic nerve. An elevated intraocular pressure (IOP) is a well documented risk factor for the development and progression of this disease. Until now, IOP reduction is the only well documented successful method of glaucoma treatment. Among the many hypotensive drugs, prostaglandin analogs are proved to be the most potent antiglaucoma agents, with very few systemic side effects. A new prostanoid FP receptor analog, tafluprost, has been introduced into the medical treatment of glaucoma and ocular hypertension. Many studies have shown that it is an efficient IOP-lowering drug, and that it is safe and well tolerated. A preservative-free tafluprost formulation is as potent as a preserved one, but it has fewer and milder toxic effects on the eye.

PG F(2α) Receptor: A Promising Therapeutic Target for Cardiovascular Disease

Prostaglandins (PGs), a group of key lipid mediators, are involved in numerous physiological and pathological processes including inflammation and cardiovascular homeostasis. Each PG acts on its specific and distinct cell surface G protein-coupled receptors (GPCRs) or peroxisome proliferator-activated receptors (PPARs). Prostaglandin F(2α) receptor (FP) is required for female reproductive function such as luteolysis and parturition. It has recently been implicated in blood pressure regulation, atherosclerosis and other inflammation-related disorders. The emerging role of FP in cardiovascular diseases is highlighted and potential therapeutic translation is discussed in the current review.

Short-term effects of topical tafluprost on retinal blood flow in cats

PURPOSE

The aim of this study was to determine the short-term effects of topical tafluprost, a novel prostaglandin F(2) derivative, on feline retinal circulation.

METHODS

Seventeen (17) adult cats were anesthetized with enflurane and mechanically ventilated. One (1) drop of tafluprost (0.0015%; n = 8), latanoprost (0.005%; n = 5), or control vehicle (n = 4) was instilled in 1 eye and the fellow eye was untreated. We measured the intraocular pressure (IOP), vessel diameter, and blood velocity simultaneously for 120 min in the large retinal arterioles and calculated the retinal blood flow (RBF) with a laser Doppler velocimetry system.

RESULTS

Tafluprost 0.0015% significantly increased RBF (maximum change, 42.8 +/- 4.2% [mean +/- standard error of the mean; P < 0.01) and blood velocity (maximum change, 24.1 +/- 3.3%; P < 0.01) for 120 min after instillation; there was no significant change in vessel diameter. Latanoprost 0.005% significantly increased RBF (maximum change, 31.7 +/- 3.4%; P < 0.05); there was no significant change in vessel diameter and blood velocity. There were no significant differences in the IOP reduction among the three groups.

CONCLUSIONS

We observed, for the first time, that topical tafluprost significantly increased RBF in cats, suggesting that dual-action tafluprost may be a beneficial antiglaucomatous agent for reducing IOP and increasing RBF.

Conjunctival and corneal reactions in rabbits following short- and repeated exposure to preservative-free tafluprost, commercially available latanoprost and 0.02% benzalkonium chloride

Aim:

To compare the conjunctival and corneal reactions of commercially available solution of latanoprost (Xalatan) and preservative-free (PF) tafluprost in rabbits.

Methods:

The rabbits received 50 μl of phosphate-buffered saline (PBS), PF-tafluprost 0.0015%, latanoprost 0.005% or benzalkonium chloride (BAK) 0.02%; all solutions were applied at 5 min intervals for a total of 15 times. The ocular surface toxicity was investigated using slit-lamp biomicroscopy examination, flow cytometry (FCM) and on imprints for CD45 and tumour necrosis factor-receptor 1 (TNFR1) conjunctival impression cytology (CIC) and corneal in vivo confocal microscopy (IVCM). Standard immunohistology also assessed inflammatory/apoptotic cells.

Results:

Clinical observation and IVCM images showed the highest ocular surface toxicity with latanoprost and BAK, while PF-tafluprost and PBS eyes presented almost normal corneoconjunctival aspects. FCM showed a higher expression of CD45+ and TNFR1+ in latanoprost- or BAK-instilled groups, compared with PF-tafluprost and PBS groups. Latanoprost induced fewer positive cells for inflammatory marker expressions in CIC specimens compared with BAK-alone, both of which were higher than with PF-tafluprost or PBS. Immunohistology showed the same tendency of toxic ranking.

Conclusion:

The authors confirm that rabbit corneoconjunctival surfaces presented a better tolerance when treated with PF-tafluprost compared with commercially available latanoprost or BAK solution.