Effect of minoxidil on rabbit lens epithelial cell behavior in vitro and in situ

[Minoxidil-induced ophthalmic hypertension (case report)]

This article presents a case of a 31-year-old male patient who presented to the outpatient department of the Krasnov Research Institute of Eye Diseases with complaints of diplopia and increased intraocular pressure (IOP) up to 30 mm Hg. The patient had been using minoxidil topically for androgenic alopecia for 8 years. On examination, mild swelling of the bulbar conjunctiva in the upper fornix was revealed; optical coherence tomography showed thinning of the ganglion cell layer, most likely due to moderate myopia. The patient responded well to discontinuation of minoxidil and topical therapy with prostaglandin analogues. After 4 months, an attempt was made to replace topical hypotensive therapy with carbonic anhydrase inhibitors, but the previous hypotensive regimen had to be resumed due to an increase in IOP. During 10 months of observation, no signs of progression were detected according to optical coherence tomography and static perimetry.

Toxicological assessment of minoxidil: A drug with therapeutic potential besides alopecia

Minoxidil is regularly prescribed for alopecia, and its therapeutic potential has expanded in recent times. However, few studies have been conducted to evaluate its toxicity, and controversial findings regarding its mutagenic activities remain unsolved. This study aimed to access cytotoxic, genotoxic, and mutagenic properties of minoxidil using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, comet assay, and micronucleus test in mouse fibroblast (L929) cells and its point mutation induction potential in the Salmonella/microsome assay. Furthermore, an in vivo toxicity assessment was conducted in Caenorhabditis elegans. Minoxidil showed cytotoxicity at 2.0 mg/mL in MTT assay. Genotoxicity was observed after 3 h treatment in L929 cells using comet assay. No mutagenic effect was observed in both the micronucleus test and the Salmonella/microsome assay. The lethal dose 50 in C. elegans was determined to be 1.75 mg/mL, and a delay in body development was detected at all concentrations. In conclusion, minoxidil induces DNA damage only in early treatment, implying that this DNA damage may be repairable. This observation corroborates the absence of mutagenic activities observed in L929 cells and Salmonella typhimurium strains. However, the toxicity of minoxidil was evident in both C. elegans and L929 cells, underscoring the need for caution in its use.

Lysyl hydroxylases are transcription targets for GATA3 driving lung cancer cell metastasis

Metastasis associates with late stages of lung cancer progression and remains the main cause of patient death due to the lack of clinically effective therapeutics. Here we report that the transcription factor GATA3 and its co-factor FOG2 commonly promote the expression of the lysyl hydroxylase (LH) family members, including LH2 and LH3, which in turn drive lung adenocarcinoma cell migration, invasion, and metastasis. We show evidence that both LH2 and LH3 are direct transcription targets for GATA3. Knockdown of either LH2 or LH3 suppresses migration and invasion; on the contrary, forced expression of LH2 or LH3 promotes growth and migration, suggesting that the two LHs exert redundant oncogenic functions. Importantly, re-expression of LH2 is sufficient to restore the metastatic capacity of GATA3-depleted cells, suggesting a role for LHs as the downstream mediators of GATA3. Collectively, our data reveal a pro-metastatic GATA3-LHs axis for lung cancer, supporting the notion that targeting LHs may be useful for treating lung cancer.

Prevention of capsule opacification after accommodating lens refilling: pilot study of strategies evaluated in a monkey model

PURPOSE

To test 2 strategies to prevent capsule opacification after accommodating lens refilling in a rhesus monkey model.

SETTING

Animal laboratory and laboratory of European university medical centers.

DESIGN

Experimental study.

METHODS

Six rhesus monkeys had refilling of the lens capsular bag. In the first strategy, before it was filled with a silicone polymer, the capsular bag was treated with noncommercial sodium hyaluronate 1.0% containing cytotoxic substances. In the second strategy, the capsular bag was filled with clinically used sodium hyaluronate 1.0% (Healon) after treatment with actinomycin-D. Slitlamp inspection was performed during a follow-up of 40 to 50 weeks. After enucleation, magnetic resonance images were obtained and confocal fluorescence imaging was performed.

RESULTS

Using the first strategy, capsule opacification developed in all eyes. Using the second strategy, 1 monkey did not develop capsule opacification after a 9-month follow-up. In a second monkey, the lens capsule remained clear for 3 months, after which the hyaluronate refill material was exchanged with a silicone polymer and capsule opacification developed. Combining these results with those in a previous study, the difference in opacification between silicone and sodium hyaluronate as refilling materials was statistically significant (P<.01).

CONCLUSIONS

That no capsular bag fibrosis occurred in the presence of hyaluronate suggests that the properties of hyaluronate are the reason that remaining lens epithelial cells do not develop into fibrotic cells. The choice of a suitable lens-refilling material prevents the development of capsule opacification.

FINANCIAL DISCLOSURE

Mr. Terwee was an employee of Abbott Medical Optics B.V. during the study period. No other author has a financial or proprietary interest in any material or method mentioned.

The intraocular lens: challenges in the prevention and therapy of infectious endophthalmitis and posterior capsular opacification

Cataract is the leading cause of visual impairment worldwide. In the UK, some 30% of the population over 65 years of age have visually impairing cataract. Importantly, 88% of those with treatable visual impairment from cataract are not in contact with any ocular healthcare service, representing a major potential healthcare need [1]. In the USA, it has been estimated that 17.2% of the population (approximately 20.5 million) over 40 years of age have cataract in either eye and by 2020, this number is expected to rise to 30.1 million. Currently, cataract is responsible for 60% of Medicare costs associated with vision [2]. Furthermore, as the populations of industrialized countries such as the UK and the USA continue to age, the costs associated with treatment of cataract can only be expected to increase. Consequently, the development of the intraocular lens to replace the cataractous lens and the advances in intraocular lens design and implantation represent a major development in cataract treatment. However, despite such advances, cataract surgery is not without complications, such as postoperative infectious endophthalmitis, a rare but potentially devastating condition, and posterior capsular opacification, a less serious but much more common problem. This review will examine the epidemiology of cataracts, the polymeric construction of intraocular lenses implanted during cataract surgery and the complications of postoperative infectious endophthalmitis and posterior capsular opacification with regard to therapeutic interventions and prophylactic strategies. Advances in biomaterial design and function will be discussed as novel approaches to prevent such postoperative complications.

Potassium channel openers increase aortic elastic fiber formation and reverse the genetically determined elastin deficit in the BN rat

Hypertension is a cardiovascular disorder that appears in more than half of the patients with Williams-Beuren syndrome, hemizygous for the elastin gene among 26 to 28 other genes. It was shown that the antihypertensive drug minoxidil, an ATP-dependent potassium channel opener, enhances elastic fiber formation; however, no wide clinical application was developed because of its adverse side effects. The Brown Norway rat was used here as an arterial elastin-deficient model. We tested 3 different potassium channel openers, minoxidil, diazoxide, and pinacidil, and 1 potassium channel blocker, glibenclamide, on cultured smooth muscle cells from Brown Norway rat aorta. All tested potassium channel openers increased mRNAs encoding proteins and enzymes involved in elastic fiber formation, whereas glibenclamide had the opposite effect. The higher steady-state level of tropoelastin mRNA in minoxidil-treated cells was attributable to an increase in both transcription and mRNA stability. Treatment of Brown Norway rats for 10 weeks with minoxidil or diazoxide increased elastic fiber content and decreased cell number in the aortic media, without changing collagen content. The minoxidil-induced cardiac hypertrophy was reduced when animals simultaneously received irbesartan, an angiotensin II-receptor antagonist. This side effect of minoxidil was not observed in diazoxide-treated animals. In conclusion, diazoxide, causing less undesirable side effects than minoxidil, or coadministration of minoxidil and irbesartan, increases elastic fiber content, decreases cell number in the aorta and, thus, could be suitable for treating vascular pathologies characterized by diminished arterial elastin content and simultaneous hypertension.

Genipin Suppresses Subconjunctival Fibroblast Migration, Proliferation and Myofibroblast Transdifferentiation

PURPOSE

Inchin-ko-to is a herbal medicine which has therapeutic effects in ameliorating liver fibrosis or cholestatic liver diseases. Its main bioactive component is genipin, which is an intestinal bacterial metabolite of this medication. Accordingly, we determined whether or not Inchin-ko-to suppresses in a wound healing model subconjunctival fibroblast (SCF) migration proliferation and myofibroblast transdifferentiation since an inhibitory effect could be of value in improving trabeculotomy outcome.

METHODS

Effects of genipin on SCF cell migration were examined subsequent to wounding confluent monolayer cultures. Alamar blue staining evaluated the effects of genipin (0-50 microg/ml) on fibroblast cell proliferation. Immunostaining determined alpha-smooth muscle actin (alphaSMA) expression. Western blotting evaluated (alphaSMA) expression and phospho-Smad2 formation. Real-time RT-PCR evaluated TGFbeta1 and collagen Ialpha2 mRNA expression. Enzyme-immunoassay determined culture medium collagen I content.

RESULTS

Genipin suppressed wound-induced cell migration and proliferation. It also decreased collagen type I TGFbeta1 and alphaSMA mRNA and protein expression. Smad2 signaling was inhibited by genipin in a dose-dependent manner.

CONCLUSION

Genipin suppresses injury-induced fibrogenic responses in SCFs. This result suggests that the herbal medicine Inchin-ko-to might have therapeutic value following trabeculotomy.

Genipin suppression of fibrogenic behaviors of the α-TN4 lens epithelial cell line

PURPOSE

To determine in a lens epithelial cell line, alpha-TN4, whether genipin, an intestinal metabolite component of the herbal medicine inchin-ko-to, suppresses profibrogenic myofibroblast generation and upregulation of fibrogenic cytokines and to evaluate the potential benefit of the medicine in preventing posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan.

METHODS

In this study, alpha-TN4 cell proliferation, migration, and expression of alpha-smooth muscle actin (alpha-SMA), the hallmark of myofibroblast generation, were assayed with a colorimetric assay, scratch wound assay, immunohistochemistry, and Western blot analysis. Gene expression of transforming growth factor-beta1 (TGF-beta1) and connective tissue growth factor (CTGF) was characterized with real-time reverse transcription-polymerase chain reaction. In addition, p38 mitogen-activated protein kinase (p 38 MAPK), extracellular signal-regulated kinase (ERK) limb, and Smad signalings were evaluated by Western blotting and immunohistochemistry. Cytotoxicity of genipin was evaluated using a commercial colorimetric assay kit for nuclear matrix protein 41/7 (NMP41/7) in culture medium.

RESULTS

Genipin suppressed cell proliferation and migration in association with inhibition of Smad and p38 MAPK phosphorylation, although ERK signaling was enhanced. Genipin suppressed mRNA expression of TGF-beta1 and CTGF. Cytoplasmic fiber formation declined based on less intense alpha-SMA immunocytochemical staining. However, alpha-SMA protein expression was actually not altered. This negative result suggests that genipin attenuated formation of alpha-SMA-containing cytoskeleton. Treatment of the cells with genipin for 48 hours did not increase the release of NMP41/7 to the medium, indicating this compound is not cytotoxic.

CONCLUSION

Because genipin suppressed alpha-TN4 lens cell fibrogenic behaviors, it may be of therapeutic value in preventing PCO.

Development of an accommodating intra-ocular lens--in vitro prevention of re-growth of pig and rabbit lens capsule epithelial cells

Cataract surgery is routinely performed to replace the clouded lens by a rigid polymeric intra-ocular lens unable to accommodate. By implanting a silicone gel into an intact capsular bag the accommodating properties of the natural lens can be maintained or enhanced. The implantation success of accommodating lenses is hampered by the occurrence of capsular opacification (PCO) due to lens epithelial cell (LEC) growth. In order to prevent LEC proliferation, a treatment regime using actinomycin D, cycloheximide and water was developed. The effectiveness of treatment was analyzed using an in vitro, MTT-based cell culture system and an ex vivo pig eye model in which the implanted lens-in-the-bag is cultured as a whole. LEC were exposed to treatment solutions for 5 min, then the cells were allowed to recover and to re-colonize the substratum. MTT conversion by cells was transiently inhibited by cycloheximide dissolved in water and by water alone. Exposure to actinomycin D resulted in a lasting inhibition of MTT conversion and consequently cell proliferation. These in vitro data could not be fully reproduced in the ex vivo pig eye model due to essential differences between both models. Treatment with actinomycin D containing solutions, however, resulted in a nearly complete absence of cells on the capsular wall. The pig eye model is a promising approach to further evaluate the effects of peri-surgical treatment during the accommodating intra-ocular lens implantation.

Loss of tumor necrosis factor alpha potentiates transforming growth factor beta-mediated pathogenic tissue response during wound healing

Animal cornea is an avascular transparent tissue that is suitable for research on wound healing-related scarring and neovascularization. Here we show that loss of tumor necrosis factor alpha (TNFalpha) potentiates the undesirable, pathogenic response of wound healing in an alkali-burned cornea in mice. Excessive invasion of macrophages and subsequent formation of a vascularized scar tissue were much more marked in TNFalpha-null knockout (KO) mice than in wild-type mice. Such an unfavorable outcome in KO mice was abolished by Smad7 gene introduction, indicating the involvement of transforming growth factor beta or activin/Smad signaling. Bone marrow transplantation from wild-type mice normalized healing of the KO mice, suggesting the involvement of bone marrow-derived inflammatory cells in this phenomenon. Co-culture experiments showed that loss of TNFalpha in macrophages, but not in fibroblasts, augmented the fibroblast activation as determined by detection of alpha-smooth muscle actin, the hallmark of myofibroblast generation, mRNA expression of collagen Ialpha2 and connective tissue growth factor, and detection of collagen protein. TNFalpha in macrophages may be required to suppress undesirable excessive inflammation and scarring, both of which are promoted by transforming growth factor beta, and for restoration of tissue architecture in a healing alkali-burned cornea in mice.

Lens epithelial cell ongrowth: Comparison of 6 types of hydrophilic intraocular lens models

PURPOSE

To compare the ongrowth of lens epithelial cells (LECs) on the anterior surface of 6 different hydrophilic intraocular lenses (IOLs).

SETTING

Medical University of Vienna, Department of Ophthalmology and Optometry, Vienna, Austria.

METHODS

Six models of hydrophilic IOLs were compared in this prospective study: Visionflex A-100 (Distra Softcryl), Rayner Centerflex 570H (Rayner), Collamer CC4204BF-IOL (Staar), Injectacryl F 3000 (Distra), Hydroview H60M (Bausch & Lomb), and MemoryLens (ORC). Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, 180, and 365 days after surgery. Lens epithelial cells in each quadrant of the anterior capsule-free lens surface were graded. The product with the highest density and the number of quadrants with this density were used to measure LEC ongrowth.

RESULTS

The Hydroview and Visionflex IOLs showed significantly more LECs than the other IOLs starting on day 7 after surgery (P < .028). There was a statistically significant difference in LEC ongrowth on the Memory IOL compared with all other IOLs from day 30 onward (P < .001). The Rayner, Collamer and Injectacryl IOLs had the fewest LECs on the anterior surface compared with all other IOLs from day 7 until the final examination.

CONCLUSIONS

The findings show that LEC ongrowth on the IOL surface is material dependent. The findings suggest that the material of the recently developed hydrophilic IOLs induces less LEC ongrowth than older models.

BMP-7 opposes TGF-beta1-mediated collagen induction in mouse pulmonary myofibroblasts through Id2

Mesenchymal cells, primarily fibroblasts and myofibroblasts, are the principal matrix-producing cells during pulmonary fibrogenesis. Transforming growth factor (TGF)-beta signaling plays an important role in stimulating the expression of type I collagen of these cells. Bone morphogenetic protein (BMP)-7, a member of the TGF-beta superfamily, has been reported to oppose the fibrogenic activity of TGF-beta1. Here, we have addressed the effects of BMP-7 on the fibrogenic activity of pulmonary myofibroblasts. We first established cell lines from the lungs of transgenic mice harboring the COL1A2 upstream sequence fused to luciferase. They displayed a spindle shape and expressed vimentin and alpha-smooth muscle actin, but not E-cadherin. COL1A2 promoter activity was dose dependently induced by TGF-beta1, which was further augmented by adenoviral overexpression of Smad3, but was downregulated by Smad7. Under the identical condition, adenoviral overexpression of BMP-7 attenuated the TGF-beta1-dependent COL1A2 promoter activity. By immunocytochemistry, the ectopic expression of BMP-7 led to the nuclear localization of phospho-Smad1/5/8 and suppressed that of Smad3. BMP-7 suppressed the expression of mRNAs for COL1A2 and tissue inhibitor of metalloproteinase-2 while increasing those of inhibitors of differentiation (Id) 2 and 3. Ectopic expression of Id2 and Id3 was found to decrease the COL1A2 promoter activity. Finally, BMP-7 and Id2 decreased TGF-beta1-dependent collagen protein secretion. In conclusion, these data demonstrate that BMP-7 antagonizes the TGF-beta1-dependent fibrogenic activity of mouse pulmonary myofibroblastic cells by inducing Id2 and Id3.

Growth factor deposition in anterior subcapsular cataract

PURPOSE

To characterize immunohistochemically the distribution of growth factors and extracellular matrix (ECM) components in an anterior subcapsular cataract (ASC) and to determine the role of growth factors in the development of ASC.

SETTING

Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan.

METHODS

During cataract surgery in 22 patients, anterior capsules with an ASC were obtained. Sections of each specimen were immunostained with a panel of antibodies against ECM components, growth factors, cytoskeletal components, and signal transduction-related molecules.

RESULTS

Collagen types I, V, and VI; fibronectin; fibrillin-1; and latent transforming growth factor beta binding protein-1 (LTBP-1) were localized to the ECM in ASC tissues. Collagen IV was localized to the ECM and the capsule. Lens epithelial cells (LECs) were positive for alpha-smooth muscle actin (alphaSMA). Lens epithelial cells and ECM stained for transforming growth factor beta2 (TGFbeta2) and TGFbeta3 in all samples, but TGFbeta1 latency-associated peptide (TGFbeta1-LAP) were detected in some samples. Fibroblast growth factor-2 (FGF-2) and hepatocyte growth factor-alpha (HGF-alpha) were localized to the ECM. Lens epithelial cells with nuclear staining for Erk-1, the mitogen-activated protein kinase (MAP kinase) cascade-related molecule, and Smad3, 1 of the Smad family members involving TGFbeta signaling, were detected.

CONCLUSIONS

Matrix components (ie, collagen types, fibronectin, fibrillin-1), as well as growth factors such as TGFbeta1-LAP, TGFbeta2, TGFbeta3, FGF-2, and HGF-alpha, were detected in ASC. Fibrillin-1 might serve as a repository for TGFbetas. These growth factors may modulate the phenotypic alteration and behavior of LECs. The MAP kinase cascade and TGFbeta signaling are both activated in LECs in ASC.

Relationship between posterior capsule opacification and intraocular lens biocompatibility

The type of healing process that occurs in response to cataract surgery and intraocular lens (IOL) implantation is dependent on a complex set of variables. Their interactions determine whether or not optical clarity is restored as a result of this procedure. In this process, wound healing entails cells undergoing either epithelial-mesenchymal transition, resulting in the generation of fibroblastic cells and accumulation of extracellular matrix, or lenticular structure formation. Such desperate cellular behaviors are regulated by the localized release of different cytokines, including transforming growth factor beta and fibroblast growth factors, which can result in post-operative capsular opacification. Other factors affecting the biological and mechanical outcome of IOL implantation are its composition, surface properties and shape.