Upregulation of GADD45α in light-damaged retinal pigment epithelial cells.

To better understand the molecular mechanisms responsible for light-induced damage in retinal pigmented epithelial (RPE) cells, we developed an automated device to recapitulate intense light exposure. When compared with human fibroblasts, ARPE-19 cells that had been exposed to blue-rich light-emitting diode-light of 10 000 Lux at 37 °C for 9 h displayed dramatic cellular apoptosis. Collectively, gene expression profiling and qPCR demonstrated that growth arrest and DNA damage-45α (GADD45α) expression was markedly upregulated. Transient knockdown of GADD45α partially attenuated light-damage-induced apoptosis in ARPE-19 cells, whereas GADD45α overexpression dramatically increased it. These results demonstrate the critical function of GADD45α in light-induced RPE cellular apoptosis. Quantitative reverse transcription-PCR and western blotting revealed that the upregulation of GADD45α was under direct control of p53. Moreover, treatment with Ly294002, an inhibitor of AKT phosphorylation, further promoted GADD45α gene transcription in both non-light and light-damaged ARPE-19 cells. Treatment also exacerbated RPE cellular apoptosis after light exposure, confirming that inhibition of Akt phosphorylation increases GADD45α expression. Collectively, our findings reveal that light irrigation induces human RPE cellular apoptosis through upregulation of GADD45α expression mediated through both the p53 and phosphatidylinositol 3-kinase-AKT signaling pathways. These results provide new insights into human retinal diseases elicited by light damage and open a new avenue for disease prevention and treatment.

Elevated cell proliferation and VEGF production by high-glucose conditions in Müller cells involve XIAP.

PURPOSE: Müller cells have important roles in the pathogenesis of diabetic retinopathy by promoting cell proliferation and inducing the production of vascular endothelial growth factor (VEGF) under hyperglycemic conditions. The objective of this study was to determine the potential mechanism of Müller cell proliferation and VEGF production due to high-glucose conditions. METHODS: Primary cultured rat Müller cells were incubated with medium containing variable concentrations of glucose and/or embelin, a specific inhibitor of X-linked inhibitor of apoptosis protein (XIAP), for 72 h. The proliferation of Müller cells was assessed by the MTT assay. The expression and/or phosphorylation of 146 proteins were assessed using protein pathway array. RESULTS: High concentrations of glucose-induced Müller cell proliferation and altered expression and/or phosphorylation of 47 proteins that have been identified to have key roles in several important signaling pathways (XIAP, VEGF, HIF1α, NFκB, etc) and are involved in the regulation of cell survival, proliferation, or apoptosis. However, Müller cell alterations induced by high-glucose conditions were counteracted by the XIAP inhibitor embelin, and 26 proteins/phosphorylations (out of 47) were restored to their normal levels. Nine proteins, including NFκB p65, p-p38, tumor necrosis factor-α, urokinase-type plasminogen activator, CREB, IL-1ß, HCAM, estrogen receptor-α, and p-Stat3, were involved in regulatory networks between XIAP and VEGF. CONCLUSIONS: The current study suggests that XIAP may be a potential regulator that can mediate a series of pathological changes induced by high-glucose conditions in Müller cells. Therefore, embelin could be a potential agent for the prevention and treatment of diabetic retinopathy.

Ratio of size of recipient and donor areas in treatment of vitiligo by autologous cultured melanocyte transplantation.

BACKGROUND: Autologous melanocytes can be expanded in vitro, allowing the treatment of large lesions of vitiligo in one session. Theoretically, this procedure could provide a higher donor/recipient size ratio (DR ratio) compared with that in noncultured cell transplantation (with a DR ratio < 1 : 10). However, the exact DR ratio obtained from this procedure has not been reported. OBJECTIVES: To study whether transplantation of cultured pure melanocytes at a high DR ratio is as efficient as that at a low DR ratio. METHODS: One hundred and two patients with vitiligo were treated by transplantation of cultured pure melanocytes and were divided into two groups: a low DR ratio group, including patients with DR ratio ≤ 1 : 10 (mean 1 : 8, 35 cases) and a high DR ratio group with DR ratio > 1 : 10 (mean 1 : 27, 67 cases). The extent of repigmentation between these two groups was compared. RESULTS: There was no significant difference in repigmentation between the low DR ratio group (mean ± SD 77·4 ± 22·5%) and the high DR ratio group (77·6 ± 24·8%). Multiple regression analysis showed that even after adjustment for age, sex, type of vitiligo and transplanted cell density, there was no significant correlation between the extent of repigmentation and the DR ratio, indicating that patients treated with high DR ratio obtained a satisfactory result and showed no difference from the low DR ratio group. CONCLUSIONS: Various surgical procedures for the treatment of vitiligo which involve melanocyte transplantation or skin grafts have different inherent DR ratios. Transplantation of cultured pure melanocytes is an expensive and complicated procedure; however, it provides the highest DR ratio (> 1 : 10 and up to 1 : 60). Surgeons can select one of these methods for the treatment of vitiligo based on their experience and skill, on the size of lesions, and the availability of laboratory support.

Treatment of vitiligo in children and adolescents by autologous cultured pure melanocytes transplantation with comparison of efficacy to results in adults.

BACKGROUND: Transplantation of autologous cultured pure melanocytes is a well-established procedure for the treatment of refractory and stabilized vitiligo. However, there was no report specifically comparing the efficacy with the regard to defined age groups (children-adolescence-adult). OBJECTIVE: We analysed the efficacy of this procedure in the treatment of vitiligo in children and adolescents and compare it with the results in adults treated during the same period and using identical procedures. METHODS: Melanocytes were isolated from the roof of suction blister, cultured and expanded with Hu16 medium in vitro, and transplanted to laser-denuded receipt area. A total of 12 children (8-12 years), 20 adolescents (13-17 years) and 70 adults with vitiligo were treated using this procedure. RESULTS: The patients obtained satisfactory results (repigmentation of 50% or more) results in children, adolescents and adults were 83.3%, 95.0% and 84.0% respectively. The mean extent of repigmentation in children, adolescents and adults was 80.7%, 78.9% and 76.6% respectively. There was no statistical difference in repigmentation among these three groups. After adjusting for all factors (gender, type of vitiligo, period of stability, location of the lesion or transplanted cell density) individually or totally using multiple regression analysis, age still did not correlate to the extent of repigmentation. CONCLUSIONS: The satisfactory results obtained in the treatment of vitiligo in children and adolescents by transplantation of cultured autologous pure melanocytes are comparable with the results in adults. Therefore, this procedure can be considered in refractory and stable vitiligo in children and adolescents, especially in patients with large vitiliginous lesions.

Cleft lip with or without cleft palate and dermatoglyphic asymmetry: evaluation of a Chinese population.

OBJECTIVE: To determine if Chinese individuals with non syndromic cleft lip with or without cleft palate (CL/P) display more dermatoglyphic asymmetry than unaffected relatives or controls. DESIGN: Case-control study with two control groups (genetically related and unrelated). SETTING AND SAMPLE POPULATION: A total of 500 CL/P probands from Shanghai, China, 421 unaffected relatives, and 66 controls of Chinese heritage. METHODS: Finger and palm prints were collected, and pattern frequencies, total ridge counts (TRC), and atd angles were calculated. Asymmetry scores between right and left hands were defined for each of the three dermatoglyphic measures. Probands' asymmetry scores were compared statistically with the scores of unaffected relatives and controls. RESULTS: In general, the probands' asymmetry scores for TRC and atd angle did not differ significantly from the scores of either unaffected relatives or controls. However, probands with a positive family history of clefting showed significantly more asymmetry in their pattern types than either probands without a family history, unaffected relatives or controls. CONCLUSION: These results suggest that a unique genetic mechanism of developmental instability may obtain in CL/P individuals with a positive family history of clefting.

Hepatocyte growth factor is increased in the aqueous humor of glaucomatous eyes.

PURPOSE: To assess the concentrations of hepatocyte growth factor (HGF) in the aqueous humor of eyes with glaucoma compared with control eyes with cataract only. METHODS: Concentrations of HGF were measured in aqueous humor aspirates taken during anterior segment surgery from 84 patients, of whom 72 had glaucoma (38 cases of primary open-angle glaucoma, 17 angle-closure glaucoma, and 17 exfoliative glaucoma) and 12 had cataract only, using a sandwich enzyme-linked immunosorbent assay kit. RESULTS: Hepatocyte growth factor was detected in all samples. The concentration in eyes with cataract only was 563.3 +/- 178.8 pg/mL (mean +/- standard deviation), which was significantly lower than that in eyes with glaucoma (967.1 +/- 514.7 pg/mL, P < 0.01). Eyes with exfoliative glaucoma had significantly higher HGF concentrations (1,425.5 +/- 586.7 pg/mL) than did eyes with primary open-angle glaucoma (855.0 +/- 341.5 pg/mL) and angle-closure glaucoma (759.4 +/- 511.4 pg/mL) (P < 0.01). There was no effect of age, sex, or history of medical, laser, or surgical treatment on the aqueous humor HGF concentration (P > 0.05). Aqueous humor and plasma HGF concentrations were measured and compared in 28 patients. The aqueous humor HGF concentration (908 +/- 586.2 pg/mL) was significantly higher (P < 0.01) than the plasma concentration (521.3 +/- 183.1 pg/mL). No significant correlation could be found between aqueous humor and plasma HGF concentrations. CONCLUSIONS: The relatively high concentration of HGF in human aqueous humor suggests that HGF may play an important role in ocular physiology and disease. The higher concentration in patients with glaucoma may indicate a response to injury.

A functional study on prostanoid receptors involved in cultured human iridal melanocyte stimulation.

The effects of various prostanoids on the growth, melanogenesis and dendrification of cultured iridal melanocytes were studied. Iridal melanocytes were isolated and cultured with medium supplemented with cAMP elevating agents and basic fibroblast growth factor (bFGF) (complete medium). The iridal melanocytes were plated into multiple well plates and cultured with complete medium or various deleted media with or without various prostanoids at different concentrations. After 6 days, the numbers of cells and dendrites were counted and melanin content was measured and compared with controls. Prostaglandin E(2), an EP(2)receptor agonist (AH 13205) and AGN 192093 (thromboxane mimetic) stimulated growth, melanogenesis and dendrification of cultured iridal melanocytes in cAMP-deleted medium. A mixed EP(1)and EP(3)receptor agonist (sulprostone), a EP(4)receptor agonist (ONO-AE1-329), IP receptor agonists (cicaprost or iloprost) and a TP receptor agonist (U-46619) showed no effect. Prostaglandin D(2)showed stimulating effects. However, these stimulating effects could not be blocked by the addition of a DP receptor antagonist (BW A868C). Furthermore, a DP receptor agonist (BW 245C) showed no effects, indicating that the effect of prostaglandin D(2)may involve receptors other than the DP receptor subtype. The present study indicates that: (1) among various EP receptor agonists, only an EP(2)receptor agonist has stimulating effects on iridal melanocytes; (2) DP, IP and TP receptor agonists do not have stimulating effects; and (3) the mechanisms of action of prostaglandin D(2)and AGN 192093 need further study.

Patterns of retinal ganglion cell survival after brain-derived neurotrophic factor administration in hypertensive eyes of rats.

We investigated the effect of brain-derived neurotrophic factor (BDNF) on retinal ganglion cell (RGC) survival after intraocular pressure (IOP) elevation at various time intervals. In adult Wistar rats, RGCs were labeled with 5% Fluorogold. Animals with 1.8-2.5-fold increase in IOP after cauterization of three episcleral vessels, were divided into three BDNF groups and three vehicle control groups, each receiving one, two or three injections. The RGC survival percentage on RGCs of the first, second and third injections were 93.9% (n = 7), 91.3% (n = 7), 82.7% (n = 5), respectively in BDNF groups; 91.6% (n = 6), 84.1% (n = 6) and 73.5% (n = 5), respectively in vehicle controls. The second and third injections of BDNF showed statistically significant survival effects. These findings demonstrated that BDNF has partial neuroprotection on RGCs in whole retina and enhances RGC survival in moderately chronic hypertensive eyes.

Characterization of a novel cationic drug transporter in human retinal pigment epithelial cells.

Retinal pigment epithelial (RPE) cells transport a variety of solutes, but the capacity of human RPE cells to transport drugs and xenobiotics is not well understood. As an initial step to address this issue, we have examined human RPE transport of verapamil. Transport of [3H]verapamil was measured in two human RPE cell lines (RPE/Hu and ARPE-19) grown to confluence on 12-well culture plates. Verapamil uptake by RPE/Hu cells was highly concentrative, reaching cell-to-medium ratios as high as 42 by 1 h. Uptake was saturable, with an apparent K(m) of 7.2 microM. Verapamil uptake decreased in the presence of metabolic inhibitors, low temperature, and organic cations, including quinidine, pyrilamine, quinacrine, and diphenhydramine. However, other organic cations, including tetraethylammonium and cimetidine failed to inhibit. Verapamil uptake was also inhibited by the cationic antiglaucoma drugs diltiazem, timolol, and propranolol. Verapamil uptake was insensitive to changes in membrane potential. However, transport was markedly altered by changes in pH. Decreasing external pH inhibited uptake, whereas efflux was stimulated. Intracellular acidification via NH4Cl prepulse also stimulated uptake. Identical findings were obtained using the commercially available cell line ARPE-19. In view of its unique specificity, the RPE cell verapamil transporter described above is a novel, heretofore undescribed, organic cation transporter, distinct from the known members of the OCT family of organic cation transporters.

The effect of combined 5-fluorouracil and dexamethasone on cultured human retinal pigment epithelial cells.

This study was designed to investigate the inhibitory effect of 5-fluorouracil (5-FU) and dexamethasone (DEX) on the proliferation of human retinal pigment epithelial (RPE) cells in vitro. The human RPE cells (R-50 cell line) were cultured and exposed to various concentrations of combined 5-FU (0, 250, 500, 1000, 2000 ng/ml) and DEX (0, 1, 10, 100, 200 micrograms/ml). The cells were incubated for 96 hr and the medium was changed every 48 hr to replenish the drug action. Cell viability was assessed using cell counting and trypan blue exclusion method. Tetrazolium salt, which can be metabolized by mitochondrial dehydrogenase to form a formazan dye, was used to assay cell proliferation. Treatment with 5-FU alone inhibited cell proliferation in a dose-dependent manner. The concentration of 5-FU that inhibited growth by 50% (IC50) was found to be 704.12 ng/ml. There was a bimodal effect of DEX on RPE cells--stimulation at low concentrations (1, 10 micrograms/ml) and inhibition at high concentrations (100, 200 micrograms/ml). When the two drugs were combined, there was additive inhibition in the concentration of 200 micrograms/ml of DEX. These results indicate that a combination of 5-FU and DEX is no more effective in the inhibition of human RPE cells, except in combination with high concentrations of DEX (> or = 200 micrograms/ml).

Regulation of growth and melanogenesis of uveal melanocytes.

We have developed methods for the isolation, cultivation, and investigation of human uveal melanocytes (UM). Uveal melanocytes grow well and produce melanin in vitro in the presence of basic fibroblast growth factor (bFGF), cyclic adenosine monophosphate-elevating agents, and serum. Cultured UM respond to various factors. Certain growth factors (bFGF and hepatocyte growth factor, etc.), endothelin, adrenergic beta2-receptor agonists, and some prostaglandins (EP2-receptor agonists and certain TP-receptor agonists) stimulate, while transforming growth factor-beta2, interleukin-6, and cholinergic agonists inhibit melanogenesis and/or growth of UM in vitro. Alpha-melanocyte-stimulating hormone, adrenocorticotropic hormone, various sex hormones, and prostaglandin F2alpha showed no effect on the growth and melanogenesis of cultured UM. The stability of UM in vivo may be controlled by these factors. Disturbance of this balance may lead to certain rare pathologic pigmentary changes of the iris. UM are relatively stable in vivo; they usually do not respond (proliferate or show dynamic changes in melanogenesis) to various environmental factors. The differences of the in vivo behavior between uveal and epidermal melanocytes may be determined by both cellular factors and environmental factors.

The combined effect of brain-derived neurotrophic factor and a free radical scavenger in experimental glaucoma.

UNLABELLED: PURPOSE. Brain-derived neurotrophic factor (BDNF) had a limited effect on the survival of retinal ganglion cells (RGCs) in rats' eyes with elevated intraocular pressure (IOP). The combined treatment of BDNF and a nonspecific free radical scavenger N-tert-butyl-(2-sulfophenyal)-nitrone (S-PBN) was investigated on the RGCs in hypertensive eyes of rats. METHODS: Adult Wistar rats were separated into five groups: BDNF (0.5 microg) + S-PBN; BDNF (1. 0 microg) + S-PBN; BDNF (1.0 microg); S-PBN; and phosphate-buffered saline. Right eyes served as normal controls (n = 10). RGCs were labeled with 5% Fluoro Gold; injected into the superior colliculus. Three days after intratectal injection, the episcleral veins of the left eyes were cauterized. Intravitreal injection of BDNF was performed on days 5, 13, 21, and 29 after IOP elevation. S-PBN was injected intraperitoneally (100 mg/kg body wt) every 12 hours starting 30 minutes after cauterization. RESULTS: The survival of RGCs using BDNF treatment alone in moderately hypertensive eyes and systemic administration of S-PBN alone did not significantly rescue the RGCs. However, the combination of BDNF and S-PBN increased the survival of RGCs to 90.1%. CONCLUSIONS: Trophic factors and antioxidants have synergistic effects on rescuing RGCs from death in eyes with elevated IOP. Further studies of different combined treatment therapies may provide avenues to save RGCs from death in eyes with elevated IOP.

Photophysical studies on melatonin and its receptor agonists.

Previous work has demonstrated that melatonin inhibits the growth of both dermal and uveal melanoma cells. Recent clinical trials have found that melatonin is an efficacious treatment for metastatic dermal melanoma. The goal of this study was to provide further insight into the oncostatic mechanism(s) of melatonin. The inhibition of the growth of uveal melanoma cells is dose-dependent (0.1-10 nM) within the range of endogenous melatonin concentrations (2 nM) found in the human aqueous humor. We know that this inhibition of growth is receptor-mediated, at least in part, because uveal melanoma cell growth was also blocked by the agonists of melatonin receptors. There are two known membrane receptors for melatonin (Mel(1a) and Mel(1b)) and one known nuclear receptor (Mel2). To determine if singlet oxygen production and/or quenching contributed to the growth inhibition of melatonin, we examined the photophysical properties of melatonin and its agonists. Using flash photolysis, we determined that melatonin and its membrane receptor agonist 6-chloromelatonin (Mel(1a-b), Lilly, Indianapolis, IN) produced very little singlet oxygen (psidelta = 0.073 and psidelta = 0.01, respectively). There was no detectable singlet oxygen phosphorescence at 1,270 nm for the nuclear receptor agonist CG-52608 (Mel2, Novartis, Basel, Switzerland). In contrast, the agonist of the Mel(1b) receptor, S-20098 (Servier, Paris, France), produced singlet oxygen with a quantum efficiency of psidelta = 0.34. Singlet oxygen was quenched by melatonin and 6-chloromelatonin at approximately the same rate (6.1 x 10(7) M(-1)s(-1) and 6.0 x 10(7) M(-1)s(-1) in CD3OD), while the rate of quenching for the nuclear receptor agonist CG-52608 and membrane receptor agonist S-20098 was less (2.2 x 10(7) M(-1)s(-1) and 1.5 x 10(7) M(-1) s(-1), respectively). It appears that the production of singlet oxygen by melatonin would not be sufficient to directly block the proliferation of melanoma cells, but may activate gene products that could contribute to the oncostatic effect.

Influence of autonomic neurotransmitters on human uveal melanocytes in vitro.

The influence of autonomic neurotransmitters on the growth and melanogenesis of cultured uveal melanocytes was studied. Uveal melanocytes were cultured with medium supplemented with cAMP elevating agents and basic fibroblast growth factor (complete medium). The cells were plated into multiple well plates, and various concentrations of adrenergic and cholinergic agents were added to the media (complete medium or various deleted media). After 6 days, the cells were detached for cell counting and melanin measurement and compared to controls. Epinephrine, isoproterenol, salbutamol and metaproterenol (adrenergic agonists that can activate beta(2)-adrenoceptors) substantially stimulated growth and melanogenesis of cultured uveal melanocytes in cAMP-deleted medium. Methoxamine, clonidine, prenalterol and D-7114 (adrenergic agonists that do not activate beta(2)-adrenoceptors) showed no effect under similar experimental conditions. Muscarine (a cholinergic agonist) inhibited the growth and melanogenesis of uveal melanocytes in complete medium. It indicates that adrenergic agents (beta(2)-adrenoceptor agonists) stimulate growth and melanogenesis in uveal melanocytes, while cholinergic agonist has an inhibitory effect. This effect appears to involve the cAMP second messenger system. These studies suggest that homeostasis of the uveal melanocytes may be maintained, in part, by regulating the autonomic nervous system in vivo.

Transplant of cultured autologous pure melanocytes after laser-abrasion for the treatment of segmental vitiligo.

Segmental vitiligo is a special type of vitiligo with unilateral distribution of lesions and has a stable course. Clinically, many patients with segmental vitiligo have unsatisfactory responses to topical corticosteroid or UV phototherapy. We have developed a technique for the isolation of melanocytes from a small specimen of normally pigmented skin obtained via a suction blister. The melanocytes can be proliferated in culture and then replanted onto laser-abrased vitiliginous areas. We used this procedure to treat 25 patients with segmental vitiligo that were refractory to medical therapy. The repigmented portion of the total treated area amounted to 95-100% in 21 patients and 65 to 94% in 4 patients. The response rate to treatment was 100% in this study. No scarring or other side-effects developed. The results of this study demonstrate that this method is a valuable tool for the treatment of patients with segmental vitiligo.

Descriptive epidemiology of nonsyndromic cleft lip with or without cleft palate in Shanghai, China, from 1980 to 1989.

OBJECTIVE: The purpose of this study was to characterize nonsyndromic cleft lip with or without cleft palate (CL+/- CP) in an Asian population. DESIGN: Birth prevalence was assessed in a large birth series in Shanghai, China. A 1:3 sex-age-hospital matched case-control design was used to assess the effects of parental ages and pregnancy history on risk of CL+/- CP. PARTICIPANTS: Records of live births from 1980 to 1989 in 22 hospitals in Shanghai, China, were reviewed, comprising 541,504 consecutive births, which is by far the largest such Chinese sample ever investigated. The case-control study included 528 (308 male, 220 female) nonsyndromic CL+/- CP cases and 1,563 (912 male, 651 female) controls. RESULTS: From 1980 to 1989, the overall birth prevalence was 1.2 per 1,000 live births with statistically significant seasonal variation (more CL+/- CP births in January to July). The overall male:female ratio was 1.40:1. For males, statistically significant associations were identified with maternal age for the most severe clefts (bilateral overall, and also bilateral CL+CP subgroup). For females, statistically significant association was shown for pregnancy age with birth order (overall and in most subgroups). CONCLUSIONS: The birth prevalence of CL+/- CP in this Asian population was similar to published Caucasian rates. The observed seasonal variation would be consistent with possible environmental factors. Significant associations with maternal age, pregnancy age, and birth order warrant additional study of pregnancy history in Asian CL+/- CP.

Melatonin receptors in human uveal melanocytes and melanoma cells.

Previous work has demonstrated that melatonin inhibits growth of cultured human uveal melanoma cells. The goal of this study was to determine the expression of mRNA encoding the melatonin receptor subtypes and the effect of specific melatonin receptor agonists on cell growth of uveal melanoma cells and melanocytes. RNA expression of the human melatonin Mel1a and Mel1b receptor subtypes was determined by reverse transcription-polymerase chain reaction (RT-PCR) amplification of RNA isolated from two melanoma cell lines and from one cell line of normal melanocytes. PCR-amplified cDNA encoding the Mel1b melatonin receptor subtype, but not the Mel1a subtype, was detected in reverse-transcribed RNA obtained from both normal uveal melanocytes and melanoma cell lines. Uveal melanoma cells and melanocytes were cultured for 24 hr, then melatonin or one of its membrane receptor agonists, 6-chloromelatonin (Mel1a-1b) or S-20098 (Mel1b) or its putative nuclear agonist, CGP-52608 (Mel2), was added to the medium. After 5 days, the cells were detached, counted, and compared to untreated controls. Melatonin and its membrane receptor agonists (Mel1a-1b and Mel1b), but not its putative nuclear receptor agonist (Mel2), inhibited the growth of uveal melanoma cells, but not normal melanocytes, at very low concentrations. In uveal melanoma cells, the expression of RNA encoding the Mel1b receptor suggests that the growth inhibiting effect of melatonin on uveal melanoma cells is related to activation of the melatonin Mel1b membrane receptor. Furthermore, the expression of RNA encoding melatonin receptors in normal uveal melanocytes suggests that melatonin may play a role in the function of these cells.

Effect of prostaglandins A(2), E(1), F(2 alpha)and latanoprost on cultured human iridal melanocytes.

The effect of various prostaglandins on the growth, melanogenesis and dendrification of cultured iridal melanocytes were studied. Iridal melanocytes were isolated and cultured with medium supplemented with cAMP elevating agents and basic fibroblast growth factor (complete medium). The iridal melanocytes were plated into multiple well plates and cultured with complete medium, cAMP-deleted medium with or without various prostaglandins at different concentrations. After 5-7 days, the numbers of cells and dendrites were counted and melanin content was measured and compared to controls. Prostaglandin A(2)and E(1)stimulated growth, melanogenesis and dendrification of cultured iridal melanocytes in cAMP-deleted medium. Prostaglandin F(2 alpha), PhXA85 and latanoprost showed no effect under similar experimental conditions. These results indicate that prostaglandin A(2)and E(1)stimulate growth and differentiation of iridal melanocytes through the activation of cAMP system. Failure of stimulation of melanogenesis of iridal melanocytes by prostaglandin F(2 alpha)and PhXA85 in vitro may be related to a different second messenger system activated by these prostaglandins and the selective stimulating effect of these prostaglandins on iridal melanocytes from mixed-colored irides.