Recovery of orbital fat pad prolapsus and deepening of the lid sulcus from topical bimatoprost therapy: 2 case reports and review of the literature

From Eye Care to Hair Growth: Bimatoprost

BACKGROUND

Bimatoprost has emerged as a significant medication in the field of medicine over the past several decades, with diverse applications in ophthalmology, dermatology, and beyond. Originally developed as an ocular hypotensive agent, it has proven highly effective in treating glaucoma and ocular hypertension. Its ability to reduce intraocular pressure has established it as a first-line treatment option, improving management and preventing vision loss. In dermatology, bimatoprost has shown promising results in the promotion of hair growth, particularly in the treatment of alopecia and hypotrichosis. Its mechanism of action, stimulating the hair cycle and prolonging the growth phase, has led to the development of bimatoprost-containing solutions for enhancing eyelash growth.

AIM

The aim of our review is to provide a brief description, overview, and studies in the current literature regarding the versatile clinical use of bimatoprost in recent years. This can help clinicians determine the most suitable individualized therapy to meet the needs of each patient.

METHODS

Our methods involve a comprehensive review of the latest advancements reported in the literature in bimatoprost formulations, which range from traditional eye drops to sustained-release implants. These innovations offer extended drug delivery, enhance patient compliance, and minimize side effects.

RESULTS

The vast literature published on PubMed has confirmed the clinical usefulness of bimatoprost in lowering intraocular pressure and in managing patients with glaucoma. Numerous studies have shown promising results in dermatology and esthetics in promoting hair growth, particularly in treating alopecia and hypotrichosis. Its mechanism of action involves stimulating the hair cycle and prolonging the growth phase, leading to the development of solutions that enhance eyelash growth. The global use of bimatoprost has expanded significantly, with applications growing beyond its initial indications. Ongoing research is exploring its potential in glaucoma surgery, neuroprotection, and cosmetic procedures.

CONCLUSIONS

Bimatoprost has shown immense potential for addressing a wide range of therapeutic needs through various formulations and advancements. Promising future perspectives include the exploration of novel delivery systems such as contact lenses and microneedles to further enhance drug efficacy and patient comfort. Ongoing research and future perspectives continue to shape its role in medicine, promising further advancements and improved patient outcomes.

Effect of retrobulbar prostaglandin analog injection on orbital fat in rats

PURPOSE

Periorbital fat atrophy is a known side effect of topical prostaglandin analogs (PA). This side effect may have implications in the treatment of diseases like thyroid orbitopathy. In this in vivo study we aimed to evaluate the effects of retrobulbar injection of three different PAs on orbital fat.

METHODS

Eighteen adult male Wistar-albino rats were divided into three groups of six animals. 0.1 ml of 0.03% bimatoprost, 0.005% latanoprost, or 0.005% travoprost was injected into the right orbits and saline was injected into the left orbits, as controls. Both orbits were exenterated after 3 weeks. Histological cross-sections were analyzed using ImageJ image analysis software. Intraconal adipocyte density was calculated.

RESULTS

There was no significant difference in the adipocyte density between the PA injected orbits and the control side in each of the three groups. When calculations from all three groups were analyzed together, again the difference in the adipocyte density between the PA injected orbits and the control side was not significant.

CONCLUSION

No significant fat atrophy was noted in this rat model three weeks after retrobulbar injection of PAs. To evaluate retrobulbar injection of PA as a potential therapy for orbital diseases with fat proliferation, in vivo studies in different animal models, higher concentrations of PA, or longer follow-up duration are required.

New role for the anandamide metabolite prostaglandin F2α ethanolamide: Rolling preadipocyte proliferation

White adipose tissue regulation is key to metabolic health, yet still perplexing. The chief endocannabinoid anandamide metabolite, prostaglandin F2α ethanolamide (PGF2αEA), inhibits adipogenesis, that is, the formation of mature adipocytes. We observed that adipocyte progenitor cells-preadipocytes-following treatment with PGF2αEA yielded larger pellet sizes. Thus, we hypothesized that PGF2αEA might augment preadipocyte proliferation. Cell viability MTT and crystal violet assays, cell counting, and 5-bromo-2'-deoxyuridine incorporation in cell proliferation ELISA analyses confirmed our prediction. Additionally, we discovered that PGF2αEA promotes cell cycle progression through suppression of the expression of cell cycle inhibitors, p21 and p27, as shown by flow cytometry and qPCR. Enticingly, concentrations of this compound that showed no visible effect on cell proliferation or basal transcriptional activity of peroxisome proliferator-activated receptor gamma could, in contrast, reverse the anti-proliferative and peroxisome proliferator-activated receptor gamma-transcription activating effects of rosiglitazone (Rosi). MTT and luciferase reporter examinations supported this finding. The PGF2αEA pharmaceutical analog, bimatoprost, was also investigated and showed very similar effects. Importantly, we suggest the implication of the mitogen-activated protein kinase pathway in these effects, as they were blocked by the selective mitogen-activated protein kinase kinase inhibitor, PD98059. We propose that PGF2αEA is a pivotal regulator of white adipose tissue plasticity, acting as a regulator of the preadipocyte pool in adipose tissue.

Cytotoxicity, Mitochondrial Functionality, and Redox Status of Human Conjunctival Cells after Short and Chronic Exposure to Preservative-Free Bimatoprost 0.03% and 0.01%: An In Vitro Comparative Study

Prostaglandin analogues (PGAs), including bimatoprost (BIM), are generally the first-line therapy for glaucoma due to their greater efficacy, safety, and convenience of use. Commercial solutions of preservative-free BIM (BIM 0.03% and 0.01%) are already available, although their topical application may result in ocular discomfort. This study aimed to evaluate the in vitro effects of preservative-free BIM 0.03% vs. 0.01% in the human conjunctival epithelial (HCE) cell line. Our results showed that long-term exposure to BIM 0.03% ensues a significant decrease in cell proliferation and viability. Furthermore, these events were associated with cell cycle arrest, apoptosis, and alterations of ΔΨ_m. BIM 0.01% does not exhibit cytotoxicity, and no negative influence on conjunctival cell growth and viability or mitochondrial activity has been observed. Short-time exposure also demonstrates the ability of BIM 0.03% to trigger reactive oxygen species (ROS) production and mitochondrial hyperpolarisation. An in silico drug network interaction was also performed to explore known and predicted interactions of BIM with proteins potentially involved in mitochondrial membrane potential dissipation. Our findings overall strongly reveal better cellular tolerability of BIM 0.01% vs. BIM 0.03% in HCE cells.

Dermatological adverse effects of anti-glaucoma eye drops: a review

Many patients are treated for glaucoma. Like other drugs, anti-glaucoma eye drops may induce dermatological adverse effects. We aim to review the dermatological adverse effects secondary to the active agents in anti-glaucoma eye drops through a literature review. In January 2020, we queried PubMed using the following MeSH terms: glaucoma/drug therapy or glaucoma, open angle/drug therapy cross-referenced with parasympathomimetics/adverse effects or adrenergic agonists/adverse effects or carbonic anhydrase inhibitors/adverse effects or prostaglandins F, synthetic/adverse effects or adrenergic beta antagonists/adverse effects or ophthalmic solutions/adverse effects. The initial search identified 1128 studies, of which 49 were excluded for being in a foreign language, 15 for not involving eye drops, 968 for not focusing on adverse dermatological effects, and 11 for insufficient documentation or redundancy. After adding 38 linked studies, we finally analysed 123 studies. The ocular and periocular dermatological adverse effects of eye drops are contact dermatitis, hyperpigmentation, prostaglandin analogue periorbitopathy, mucous membrane pemphigoid, eyelash depigmentation, skin hypertrichosis, and rare cases of melanoma and skin depigmentation. The reported distant dermatological adverse effects are psoriasis, excessive sweating, lichen planus, alopecia, toxic epidermal necrolysis, erythema multiforme, erythroderma, subacute cutaneous lupus erythematosus, nail pigmentation and bullous pemphigoid. Most of the cutaneous adverse effects of anti-glaucoma eye drops are ocular and periocular and induced by prostaglandin analogues. Distant adverse effects are rare and sometimes questionable but should be kept in mind, especially mucous membrane pemphigoid, which could lead to blindness. The role of preservatives, such as benzalkonium chloride, should also be considered.

Changes in peri-ocular anatomy and physiology in pseudoexfoliation syndrome (Review)

Pseudoexfoliation syndrome (PEX) is characterized by the deposition of proteinaceous material in the anterior ocular segment (resulting in ophthalmic pathologies such as glaucoma and increased risk of complications in cataract surgery), but also by several systemic manifestations. The involvement of peri-ocular tissues in PEX, including the eyelid skin, lacrimal gland, conjunctiva, orbital fat and vessels, as well as the optic nerve, has been reported by several previous studies. The peri-ocular effects of PEX include the development of eyelid laxity, conjunctival chalasis, tear film abnormalities, pronounced orbital fat atrophy in response to the administration of prostaglandin analogues in pseudoexfoliative glaucoma, deficient orbital vascular supply and biomechanical changes in both the eyeball and the optic nerve. These effects may have important clinical implications, including increased difficulty in cataract surgery, ocular surface disease and eyelid margin malpositions.

Pretarsal skin height changes in children receiving topical prostaglandin analogue therapy for primary congenital glaucoma

PURPOSE

To compare pretarsal skin height (PTSH), as proxy indicator of deepening of the upper eyelid sulcus, in children with primary congenital glaucoma (PCG) treated with topical prostaglandin analogues (PGAs) with PTSH in healthy children (control group 1) and children with PCG but not using PGAs (control group 2).

METHODS

We recruited children with PCG who had been using PGAs for at least 6 months (PCG/PGA group). PTSH in all participants was measured using ImageJ software from photographs taken in a standardized manner. The PTSH was compared for the PCG group and both control groups.

RESULTS

A total of 34 children with PCG and 41 controls (31 in group 1; 10 in group 2) were included. The difference in PTSH between children in the PCG/PGA group and both control groups was statistically significant (mean difference, ≥1.7 mm [P < 0.01]).

CONCLUSIONS

The PTSH was significantly greater in children with PCG using PGAs compared to children with PCG not using PGAs and healthy children. Children and their parents should be counseled about lid abnormalities prior to commencing treatment with PGAs.

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.

Factors Related to Prostaglandin-Associated Periorbitopathy in Glaucoma Patients

PURPOSE

To determine factors related to prostaglandin-associated periorbitopathy (PAP) and its prevalence in glaucoma or ocular hypertension (OHT) patients using prostaglandins analogs (PGAs).

DESIGN

A cross-sectional study.

METHODS

A study of glaucoma or OHT patients, using topical PGAs for at least 3 months, was performed. Eyes treated with PGAs were photoraphed and independently evaluated for PAP by 2 glaucoma specialists using at least 4 out of 7 clinical appearances. The factors of interest were sex, age, body mass index (BMI), types of glaucoma, types of PGAs, duration of PGA use, and concurrent 0.5% timolol. Univariate (χ2 test) and multivariate (multiple logistic regression) analyses assessing risk factors for PAP were performed to estimate the odds ratios (OR) with 95% conidence intervals (CIs).

RESULTS

One hundred thirty-four eyes from 134 patients were included. Seventy (52.2%), 21 (15.7%), and 43 (32%) eyes received components of latanoprost, travoprost, and bimatoprost, respectively. Prevalence of PAP was 44.8% (95% CI, 36.3 to 53.3). Older age >60 years (OR, 3.0; 95% CI, 1.2 to 7.8), bimatoprost (OR, 4.0; 95% CI, 1.6 to 9.5), travoprost (OR, 3.3; 95% CI, 1.1 to 10.1), and timolol (OR, 2.9; 95% CI, 1.3 to 6.8) were at risk of PAP development. In addition, BMI ≥23 kg/㎡ (OR, 0.3; 95% CI, 0.1 to 0.7) was reversely associated with PAP.

CONCLUSIONS

Older age, bimatoprost, or travoprost were associated with PAP, whereas high BMI was found as a protective factor. Interestingly, timolol possibly precipitated periorbital change when in use with prostaglandins.

In Vivo Effects of Retrobulbar Bimatoprost Injection on Orbital Fat

PURPOSE

Recent publications have reported the adverse effects of prostaglandin analogues on the periocular tissues. These medications may cause periorbital lipodystrophy, enophthalmos, and deepening of the superior sulcus deformity. While these effects may have adverse consequences for some patients, the atrophy of the periorbital fat may have a useful role in diseases that lead to orbital and periorbital fat hypertrophy such as thyroid eye disease. In this pilot study, the authors investigated the effects of retrobulbar bimatoprost injection on the intraocular pressure and orbital fat in a rat animal model.

METHODS

Three rats were sedated and intraocular pressure was measured. A 0.1 ml aliquot of bimatoprost was injected into the right orbit of all rats. In the left orbit, 0.1 ml of phosphate-buffered saline was injected as a control. Three weeks later, all rats were sedated and intraocular pressure was measured before euthanizing. Routine histologic staining was performed and thin sections through the intraconal orbital fat were obtained. Density of intraconal adipocytes was measured and adipocyte heterogeneity was determined using a computer image analysis algorithm.

RESULTS

The specimens injected with bimatoprost demonstrated atrophy of orbital fat with significantly increased adipocyte density (p = 0.009) and heterogeneity (p = 0.008) when compared with control. Intraocular pressure was not significantly decreased at 3 weeks after injection of retrobulbar bimatoprost.

CONCLUSIONS

In this pilot study, orbital injection of bimatoprost demonstrated atrophy of intraconal adipocytes when compared with control orbits injected with saline. The orbits injected with bimatoprost were noted to have smaller, more heterogeneous adipocytes that were densely packed in the intraconal space. The study limitations include the small sample size, which limited the ability for us to make conclusions about the effect on intraocular pressure. Nevertheless, the findings presented suggest that retrobulbar bimatoprost may present a nonsurgical alternative to induce atrophy of the orbital fat without inducing inflammation or hypotony.

Unilateral Prostaglandin-Associated Periorbitopathy: A Syndrome Involving Upper Eyelid Retraction Distinguishable From the Aging Sunken Eyelid

PURPOSE

To study the effects of prostaglandin analogue drops on the eyelids and adnexa in unilaterally treated subjects with the intention of qualifying, quantifying, and categorizing the characteristics of prostaglandin-associated periorbitopathy (PAP).

METHODS

Patients using prostaglandin analogue drops in only 1 eye for at least 1 year were evaluated by masked examiners. Orbital and eyelid measurements were obtained for each patient, and adnexal photographs were taken. PAP was divided into 3 grades based on the presence and severity of fat atrophy and the existence and depth of superior sulcus deformity. Statistical analysis was performed comparing data between treated and untreated eyes.

RESULTS

Thirty-three patients meeting eligibility criteria were enrolled, with equal numbers of subjects using latanoprost, travoprost, and bimatoprost. Treated eyes had a statistically significant increase in lagophthalmos (0.62 mm, p < 0.001), superior sulcus deformity/PAP grade (0.72, p < 0.001), and eyelid redness (1.08, p < 0.001). Treated eyes had significantly greater marginal reflex distance 1 measurements (0.89 mm, p = 0.02), highest with bimatoprost and moderate PAP. Treated eyes had relatively greater enophthalmos than untreated eyes. Very few patients noticed or complained about eyelid changes.

CONCLUSION

Prostaglandin analogue drops cause adnexal changes and orbital fat atrophy leading to eyelid redness, superior sulcus deformity, higher eyelid crease, and enophthalmos. In contrast to previous studies showing ptosis in PAP, relative upper eyelid retraction was seen in most of our treated eyes. Our novel PAP grading scale may help objectify and categorize this syndrome. Awareness of these signs is critical, as the eyelids and eyes may be affected even in the absence of patient recognition.

The exit strategy: Pharmacological modulation of extracellular matrix production and deposition for better aqueous humor drainage

Primary open angle glaucoma (POAG) is an optic neuropathy and an irreversible blinding disease. The etiology of glaucoma is not known but numerous risk factors are associated with this disease including aging, elevated intraocular pressure (IOP), race, myopia, family history and use of steroids. In POAG, the resistance to the aqueous humor drainage is increased leading to elevated IOP. Lowering the resistance and ultimately the IOP has been the only way to slow disease progression and prevent vision loss. The primary drainage pathway comprising of the trabecular meshwork (TM) is made up of relatively large porous beams surrounded by extracellular matrix (ECM). Its juxtacanalicular tissue (JCT) or the cribriform meshwork is made up of cells embedded in dense ECM. The JCT is considered to offer the major resistance to the aqueous humor outflow. This layer is adjacent to the endothelial cells forming Schlemm's canal, which provides approximately 10% of the outflow resistance. The ECM in the TM and the JCT undergoes continual remodeling to maintain normal resistance to aqueous humor outflow. It is believed that the TM is a major contributor of ECM proteins and evidence points towards increased ECM deposition in the outflow pathway in POAG. It is not clear how and from where the ECM components emerge to hinder the normal aqueous humor drainage. This review focuses on the involvement of the ECM in ocular hypertension and glaucoma and the mechanisms by which various ocular hypotensive drugs, both current and emerging, target ECM production, remodeling, and deposition.

Prostaglandin-Associated Periorbital Lipodystrophy in Cosmetic Eyelid Surgery: A Novel Cause of Facial Asymmetry

A 70-year-old woman presented to our practice with profound ptosis of the left upper eyelid and notable asymmetry of the periocular area. On examination, she was noted to have significant atrophy of the periocular tissues on the left side, with lower eyelid retraction. These features were present but less severe on the right side. Upon further questioning, she stated that she had cataract surgery on the left side that was complicated by a high intraocular pressure and required subsequent secondary surgery. She had taken a prostaglandin eyedrop for many months after her cataract surgery to keep the eye pressure low. Recently, a newly recognized adverse effect of prostaglandin eyedrops has been described in the ophthalmic literature in which patients develop periorbital lipodystrophy. This case emphasizes that this may occur unilaterally in patients taking the eyedrop in only one eye, and should be recognized prior to considering functional and aesthetic surgery of the periocular area.

Incidence of deepening of the upper eyelid sulcus in prostaglandin-associated periorbitopathy with a latanoprost ophthalmic solution

PURPOSE

Among some local side effects of prostaglandin-associated periorbitopathy (PAP), deepening of the upper eyelid sulcus (DUES) is the most prominent clinical feature, and is one of the most significant adverse cosmetic events. Here, we prospectively investigated the incidence of DUES in Japanese open-angle glaucoma patients initially treated with latanoprost (Xalatan 0.005%) ophthalmic solution.

METHODS

This was an open-label prospective study. Facial photographs and subjective reports of the recognition of DUES were obtained at the beginning of latanoprost treatment and at 2, 4, and 6 months thereafter. Intraocular pressure (IOP) was measured at three consecutive visits before and after treatment with latanoprost. The incidence of DUES was evaluated objectively by three blinded investigators who compared the series of photographs.

RESULTS

A total of 52 eyes of 52 newly diagnosed open-angle glaucoma Japanese patients (28 males, 24 females) were evaluated. The objective rate of DUES was 1/52 (2%; 95% CI 0.05 to 10.7%) at 2 months, 2/52 (4%; 95% CI 0.5 to 13.9%) at 4 months, and 3/52 (6%; 95% CI 1.2 to 16.9%) at 6 months. During this period, no patient self-reported an occurrence of DUES. Mean IOPs before and after treatment were 16.5±2.9 and 13.8±3.0 mm Hg, respectively. Latanoprost reduced the IOP significantly (P<0.0001, paired t-test).

CONCLUSIONS

Latanoprost caused DUES rarely and had a robust IOP-lowering effect in Japanese glaucoma patients.

Effects of prostaglandin F(2α) on adipocyte biology relevant to graves' orbitopathy

BACKGROUND

In Graves' orbitopathy (GO), increased proliferation, excess adipogenesis, and hyaluronan overproduction produce GO exophthalmos. Enophthalmos occurs in some glaucoma patients treated with Bimatoprost (prostaglandin F2α, PGF2α) eye drops. We hypothesized that enophthalmos is secondary to reductions in orbital tissue proliferation, adipogenesis, and/or increased lipolysis. We aimed to determine which of these is affected by PGF2α by using the 3T3-L1 murine preadipocyte cell line and primary human orbital fibroblasts (OFs) from GO patients (n=5) and non-GO (n=5).

METHODS

3T3-L1 cells and orbital OFs were cultured alone or with PGF2α (all experiments used 10(-8) to 10(-6) M) and counted on days 1/2/3 or 5, respectively; cell cycle analysis (flow cytometry) was applied. Adipogenesis (in the presence/absence of PGF2α) was evaluated (day 7 or 15 for 3T3-L1 and primary cells, respectively) morphologically by Oil Red O staining and quantitative polymerase chain reaction measurement of adipogenesis markers (glycerol-3-phosphate dehydrogenase and lipoprotein lipase, respectively). For lipolysis, in vitro-differentiated 3T3-L1 or mature orbital adipocytes were incubated with norepinephrine and PGF2α and free glycerol was assayed. Appropriate statistical tests were applied.

RESULTS

The population doubling time of 3T3-L1 was 27.3±1.4 hours-significantly increased by dimethyl sulfoxide 0.02% to 44.6±4.8 hours (p=0.007) and further significantly increased (p=0.049 compared with dimethyl sulfoxide) by 10(-8) M PGF2α to 93.6±19.0 hours, indicating reduced proliferation, which was caused by prolongation of G2/M. GO OFs proliferated significantly more rapidly than non-GO (population doubling time 5.36±0.34 or 6.63±0.35 days, respectively, p=0.035), but the proliferation of both was significantly reduced (dose dependent from 10(-8) M) by PGF2α, again with prolongation of G2/M. Adipogenesis in 3T3-L1 cells was minimally affected by PGF2α when assessed morphologically, but the drug significantly reduced transcripts of the glycerol-3-phosphate dehydrogenase differentiation marker. GO OFs displayed significantly higher adipogenic potential than non-GO, but in both populations, adipogenesis, evaluated by all 3 methods, was significantly reduced (dose dependent from 10(-8) M) by PGF2α. There was no effect of PGF2α on basal or norepinephrine-induced lipolysis, in 3T3-L1 or human OFs, either GO or non-GO.

CONCLUSIONS

The results demonstrate that PGF2α significantly reduces proliferation and adipogenesis and that human OFs are more sensitive to its effects than 3T3-L1. Consequently, PGF2α could be effective in the treatment of GO.

Recent progress in prostaglandin F2α ethanolamide (prostamide F2α) research and therapeutics

Prostamide (prostaglandin ethanolamide) research emerged from two distinct lines of research: 1) the unique pharmacology of the antiglaucoma drug bimatoprost and 2) the discovery that endocannabinoid anandamide was converted by COX-2 to a series of electrochemically neutral prostaglandin (PG) ethanolamides. Bimatoprost pharmacology was found to be virtually identical to that of prostamide F2α. The earliest studies relied on comparison of agonist potencies compared with PGF2α and synthetic prostaglandin F2α (FP) receptor agonists. The subsequent discovery of selective and potent prostamide receptor antagonists (AGN 211334-6, as shown in Fig. 3) was critical for distinguishing between prostamide and FP receptor-mediated effects. The prostamide F2α receptor was then modeled by cotransfecting the wild-type FP receptor with an mRNA splicing variant (altFP4).Bimatoprost is now used therapeutically for treating both glaucoma and eyelash hypotrichosis. Bimatoprost also stimulates hair growth in isolated human scalp hair follicles. A strong effect is also seen in mouse pelage hair, where bimatoprost essentially halves the onset of hair regrowth and the time to achieve full hair regrowth in shaved mice. Beyond glaucoma and hair growth, bimatoprost has potential for reducing fat deposition. Studies to date suggest that preadipocytes are the cellular target for bimatoprost. The discovery of the enzyme prostamide/PGF synthase was invaluable in elucidating the anatomic distribution of prostamide F2α. High expression in the central nervous system provided the impetus for later studies that described prostamide F2α as a nociceptive mediator in the spinal cord. At the translational level, bimatoprost has already provided therapeutics in two distinct areas and the use of both prostamide agonists and antagonists may provide other useful medicaments.

Anandamide-derived prostamide F2α negatively regulates adipogenesis

Lipid mediators variedly affect adipocyte differentiation. Anandamide stimulates adipogenesis via CB1 receptors and peroxisome proliferator-activated receptor γ. Anandamide may be converted by PTGS2 (COX2) and prostaglandin F synthases, such as prostamide/prostaglandin F synthase, to prostaglandin F2α ethanolamide (PGF2αEA), of which bimatoprost is a potent synthetic analog. PGF2αEA/bimatoprost act via prostaglandin F2αFP receptor/FP alt4 splicing variant heterodimers. We investigated whether prostamide signaling occurs in preadipocytes and controls adipogenesis. Exposure of mouse 3T3-L1 or human preadipocytes to PGF2αEA/bimatoprost during early differentiation inhibits adipogenesis. PGF2αEA is produced from anandamide in preadipocytes and much less so in differentiating adipocytes, which express much less PTGS2, FP, and its alt4 splicing variant. Selective antagonism of PGF2αEA receptors counteracts prostamide effects on adipogenesis, as does inhibition of ERK1/2 phosphorylation. Selective inhibition of PGF2αEA versus prostaglandin F2α biosynthesis accelerates adipogenesis. PGF2αEA levels are reduced in the white adipose tissue of high fat diet-fed mice where there is a high requirement for new adipocytes. Prostamides also inhibit zebrafish larval adipogenesis in vivo. We propose that prostamide signaling in preadipocytes is a novel anandamide-derived antiadipogenic mechanism.

A cross-sectional survey of the association between bilateral topical prostaglandin analogue use and ocular adnexal features

We studied the relation between prostaglandin analogue use and ocular adnexal features. We used a prospective, cross-sectional study involving 157 current, 15 past, and 171 never users of prostaglandin analogues. Patients 50 years of age or older and without conditions affecting ocular adnexal anatomy underwent glaucoma medication use history, external digital photography and systematic external adnexal exam. Two masked readers assessed the digital photos for upper lid dermatochalasis and lower lid steatoblepharon using a validated grading scheme. Another masked clinical examiner also assessed upper lid ptosis, levator muscle function, and inferior scleral show. We performed ordinal logistic regression analysis accounting for multiple covariates to assess the relation between prostaglandin analogue use and adnexal features. Multivariable analyses indicated there was a 230-fold increased risk of incremental involution of dermatochalasis (odds ratio (OR)  =  2.30; 95% confidence interval (CI) 1.43–3.69; p = 5.44E-04) and a 249-fold increased risk of incremental loss of lower lid steatoblepharon (OR  =  2.49; 95% CI, 1.54–4.03; p =  1.98E-04) associated with current prostaglandin analogue use (bimatoprost 0.03%, travoprost 0.005%, or latanoprost 0.004%) versus prostaglandin analogue never or past users. Upper lid ptosis (OR  =  4.04; 95% CI, 2.43–6.72; p = 7.37E-08), levator dysfunction (OR =  7.51; 95% CI, 3.39–16.65; p = 6.74E-07) and lower lid retraction (OR = 2.60; 95% CI, 1.58–4.28; p = 1.72E-04) were highly associated with current prostaglandin analogue use versus prostaglandin analogue never or past users. The associations between prostaglandin analogue use and deepening of the upper lid sulci and between prostaglandin analogue use and loss of inferior periorbital fat are confirmed in this multivariable analysis. The associations between prostaglandin analogue use and levator muscle dysfunction and between prostaglandin analogue use and upper lid ptosis represent significant side effects that could impact visual function in glaucoma patients.

Recovery from deepening of the upper eyelid sulcus after switching from bimatoprost to latanoprost

PURPOSE

Although useful for reducing intraocular pressure (IOP), bimatoprost (BIM) can cause deepening of the upper eyelid sulcus (DUES), one of the symptoms of prostaglandin-associated periorbitopathy (PAP). We investigated recovery from BIM-induced DUES after switching treatment to latanoprost (LAT).

DESIGN

Prospective, observer-masked, open-label study.

METHODS

Twenty-five Japanese patients suffering from primary open-angle glaucoma treated with LAT in both eyes for longer than 6 months and requiring further IOP reduction were prospectively enrolled in the study. During the first 6 months after the switch to BIM, 15 of the 25 patients (60 %) developed DUES. Among these patients, 13 were switched back to LAT and re-examined for DUES at 2-month intervals for an additional 6 months.

RESULTS

Two months after the switch back to LAT, for 11 of the 13 patients (85 %) the DUES symptoms had either decreased or disappeared, and this was maintained for at least 6 months. During this time, 6 of 8 patients (75 %) subjectively positive for DUES self-reported a decrease in DUES.

CONCLUSIONS

Although DUES is a frequent side effect of treatment with BIM, switching to LAT may reverse the condition for most patients.

Iris and periocular adverse reactions to bimatoprost in Japanese patients with glaucoma or ocular hypertension

PURPOSE

To prospectively investigate adverse reactions to bimatoprost in Japanese patients with glaucoma or ocular hypertension. We also examined patient attitudes to adverse reactions via a questionnaire.

METHODS

Fifty-two Japanese patients with glaucoma or ocular hypertension were enrolled. Iridial, eyelid, and eyelash photographs were taken before and at 6 months after bimatoprost treatment. Increase in eyelid pigmentation, iridial pigmentation, eyelash growth and bristle, and vellus hair of the lid was assessed from the photographs. Questionnaires completed by patients provided insight into their subjective judgment of adverse reactions.

RESULTS

Increase in eyelash bristle (53.8%), iris pigmentation (50.0%), eyelash growth (46.2%), vellus hair of the lid (40.4%), and eyelid pigmentation (7.7%) was evident after bimatoprost treatment. The objective and subjective assessments were in agreement in terms of increase in eyelash bristle, eyelash growth, and increase in vellus hair of the lid.

CONCLUSION

Most patients were conscious of these adverse reactions. Before administering bimatoprost, sufficient explanation of potential adverse reactions should be provided; after initiating treatment, careful observation is required.