Caffeic acid phenethyl ester to inhibit posterior capsule opacification in rabbits

Comparison of the Rate of Posterior Capsule Opacification Following Combined Treatment With Topical Dexamethasone 0.1% Plus Ketorolac 0.5% Eye Drops Versus Dexamethasone 0.1% Alone: A Two-Year, Randomized Clinical Investigation

Background and aim The use of non-steroidal anti-inflammatory drugs in animals decreases the incidence of posterior capsular opacification (PCO) following cataract surgery. We evaluated the rate of PCO in patients with cataract surgery and foldable "in the bag" posterior chamber intraocular lens (PC-IOL) implantation treated with combined dexamethasone 0.1% plus ketorolac tromethamine 0.5% versus dexamethasone 0.1% alone. Materials and methods A total of 114 eyes of 101 patients underwent uneventful corneal small-incision phacoemulsification with primary implantation of a foldable acrylic PC-IOL (AcrySof^®, Alcon, Fort Worth, USA). Postoperatively for four weeks, group 1 eyes were treated with dexamethasone 0.1% plus ketorolac tromethamine 0.5% ophthalmic solutions four times daily for each whereas group 2 eyes were treated with dexamethasone 0.1% alone. Other regiments were the same for each group. Patients were evaluated between one- and four-year following surgery. The frequency and timing of severe PCO following surgery that needed Nd:YAG laser posterior capsulotomy were recorded and evaluated. Results The mean (SEM) age of group 1 (n = 54) and group 2 (n = 60) at operation was similar (62.8 ± 2.2 vs. 60.6 ± 1.7 years, respectively). Eighty-eight patients had unilateral cataract and 13 cases had bilateral disease. Overall, the mean follow-up duration was 24.7 months postoperatively (range, 15-48). Clinically significant PCO that finally needed Nd:YAG laser application developed in two eyes (3.7%) in group 1 and in four eyes (6.6%) in group 2, and the difference was not statistically significant (p>0.05). The mean month at capsulotomy was 26.5 in group 1 and 24.3 months in group 2 eyes (p>0.05). Conclusions Topical instillation of ketorolac ophthalmic solution in the immediate period after phacoemulsification and PC-IOL implantation did not seem to influence the incidence of PCO formation two years after cataract surgery.

Protective Effect of Natural Antioxidants on Reducing Cisplatin-Induced Nephrotoxicity

The clinical application of cisplatin is limited by its adverse events, of which nephrotoxicity is the most commonly observed. In a cisplatin-induced pathological response, oxidative stress is one of the upstream reactions which inflicts different degrees of damages to the intracellular material components. Reactive oxygen species (ROS) are also one of the early signaling molecules that subsequently undergo a series of pathological reactions, such as apoptosis and necrosis. This review summarizes the mechanism of intracellular ROS generation induced by cisplatin, mainly from the consumption of endogenous antioxidants, destruction of antioxidant enzymes, induction of mitochondrial crosstalk between the endoplasmic reticulum by ROS and Ca²⁺, and destruction of the cytochrome P450 (CYP) system in the endoplasmic reticulum, all of which result in excessive accumulation of intracellular ROS and oxidative stress. In addition, studies demonstrated that natural antioxidants can protect against the cisplatin-induced nephrotoxicity, by reducing or even eliminating excess free radicals and also affecting other nonredox pathways. Therefore, this review on the one hand provides theoretical support for the research and clinical application of natural antioxidants and on the other hand provides a new entry point for the detailed mechanism of cisplatin nephrotoxicity, which may lay a solid foundation for the future clinical use of cisplatin.

Recent progresses in the pharmacological activities of caffeic acid phenethyl ester

The past decades have seen a growing interest in natural products. Caffeic acid phenethyl ester (CAPE), a flavonoid isolated from honeybee propolis, has shown multiple pharmacological potentials, including anti-cancer, anti-inflammatory, antioxidant, antibacterial, antifungal, and protective effects on nervous systems and multiple organs, since it was found as a potent nuclear factor κB (NF-κB) inhibitor. This review summarizes the advances in these beneficial effects of CAPE, as well as the underlying mechanisms, and proposes that CAPE offers an opportunity for developing therapeutics in multiple diseases. However, clinical trials on CAPE are necessary and encouraged to obtain certain clinically relevant conclusions.

Aldose reductase inhibition enhances lens regeneration in mice

After cataract surgery, epithelial cells lining the anterior lens capsule can transition to one of two divergent pathways, including fibrosis which leads to posterior capsular opacification (PCO), or lens fiber cell differentiation which leads to regeneration of lens material. We previously showed that the PCO response can be suppressed with aldose reductase (AR) inhibitors. In this present study we show that AR inhibition, both genetic and pharmacologic with Sorbinil, can augment the process of lens regeneration. Extracapsular lens extraction (ECLE) was carried out in C57BL/6 (WT), AR overexpression (AR-Tg), and AR knockout (ARKO) mice, and in some cases in mice treated with the AR inhibitor sorbinil. Whole eyes were harvested approximately 8 weeks after ECLE and evaluated by histological analysis and immunostaining for the fiber cell marker γ-crystallin. All eyes examined for lens regeneration were paraffin embedded for serial sectioning to produce three-dimensional reconstructed models of lens morphology and size. We observed that AR-null mice respond to ECLE by regenerating a lens-like structure with a circular shape and array of cell nuclei reminiscent of the lens bow region typical of the native mammalian lens. Although WT and AR-Tg eyes also produced some regenerated lens material after ECLE, their structures were consistently smaller than ARKO regenerated lenses. WT mice treated with sorbinil showed higher levels of lens regeneration after ECLE compared to WT mice, as assessed by size and three-dimensional morphology. Altogether, this study adds evidence for a critical role for AR in the response of lens epithelial cells to cataract extraction and lens regeneration.

Aldose Reductase Inhibition Prevents Development of Posterior Capsular Opacification in an In Vivo Model of Cataract Surgery

Purpose

Cataract surgery is a procedure by which the lens fiber cell mass is removed from its capsular bag and replaced with a synthetic intraocular lens. Postoperatively, remnant lens epithelial cells can undergo an aberrant wound healing response characterized by an epithelial-to-mesenchymal transition (EMT), leading to posterior capsular opacification (PCO). Aldose reductase (AR) inhibition has been shown to decrease EMT markers in cell culture models. In this study, we aim to demonstrate that AR inhibition can attenuate induction of EMT markers in an in vivo model of cataract surgery.

Methods

A modified extracapsular lens extraction (ECLE) was performed on C57BL/6 wildtype, AR overexpression (AR-Tg), and AR knockout mice. Immunofluorescent staining for the myofibroblast marker α-smooth muscle actin (α-SMA), epithelial marker E-cadherin, and lens fiber cell markers αA-crystallin and Aquaporin 0 was used to characterize postoperative PCO. Quantitative reverse transcription PCR (qRT-PCR) was employed to quantify postoperative changes in α-SMA, vimentin, fibronectin, and E-cadherin. In a separate experiment, the AR inhibitor Sorbinil was applied postoperatively and qRT-PCR was used to assess changes in EMT markers.

Results

Genetic AR knockout reduced ECLE-induced upregulation of α-SMA and downregulation of E-cadherin. These immunofluorescent changes were mirrored quantitatively in changes in mRNA levels. Similarly, Sorbinil blocked characteristic postoperative EMT changes in AR-Tg mice. Interestingly, genetic AR knockout did not prevent postoperative induction of the lens fiber cell markers αA-crystallin and Aquaporin 0.

Conclusions

AR inhibition prevents the postoperative changes in EMT markers characteristic of PCO yet preserves the postoperative induction of lens fiber cell markers.

Effects of intralipid and caffeic acid phenyl esther (CAPE) against hepatotoxicity and nephrotoxicity caused by glyphosate isopropylamine (GI)

This study was aimed to investigate the protective effects of caffeic acid phenyl esther (CAPE) and Intralipid (IL) against hepatotoxicity and nephrotoxicity caused by acute intoxication of glyphosate (N-phosphonomethyl)glycine) (GI) in rats. Forty-nine Wistar Albino rats were randomly divided into seven groups as: I, Control; II, Intralipid (IL) (18.6 mL/kg, orally); III, CAPE (10 µmol/kg, intraperitoneally); IV, GI (4 mg/kg/day, intraperitoneally); V, GI + IL; VI, GI+CAPE; and VII, GI + IL + CAPE. Total antioxidant status (TAS) and total oxidant status (TOS) levels were measured in serum samples. Tissues were analyzed with hematoxylin and eosin (H&E) staining protocol. Bcl-2, Bax, and caspase-3 were evaluated by immunohistochemical method. The results revealed that, in hepatic tissues, the TAS levels were lower and the TOS levels were higher in the GI group compared to other groups. In renal tissues, the TAS levels were significantly lower in the GI group than in the control, IL, CAPE, and GI + IL + CAPE groups. The TOS levels were significantly higher in the GI group than in the control group. Moreover, histopathological analysis revealed severe hepatotoxicity in the GI group. In the GI + CAPE + IL group, hepatotoxicity recovered significantly. Nephrotoxicity was also observed in the GI group and moderately reduced in the GI + CAPE group. Biochemical results were confirmed by histopathologic examination. The results also revealed that CAPE and IL, due to their antioxidant effects, have a decreasing effect against both hepatotoxicity and nephrotoxicity caused by GI. Therefore, CAPE and IL may function as potential agents for supportive therapy since they decrease organ damage, or may facilitate the therapeutic effects of the routine treatment of patients with GI poisoning.

The role of CAPE in PI3K/AKT/mTOR activation and oxidative stress on testis torsion

Ischemia reperfusion injury arises from testicular torsion resulting in a loss of spermatogenesis and significant germ cell apoptosis. This study evaluates the prooxidant/antioxidant effects of caffeic acid phenethyl ester (CAPE) through PI3K/AKT/mTOR signal pathways on testis torsion. A total of (28) male Wistar rats were divided randomly into 4 groups (n=7 for each group):group A (sham) group,group B torsion/detorsion group, group C (saturation group, during four days of CAPE, one dose (10 μmol/kg, i.p)) and group D (a single dose of CAPE 2h after torsion and before detorsion). At the end of the study, unilateral orchiectomies were performed for measurements of MDA and 8OHdG levels, histopathologic and immunohistochemical and TUNEL apoptotic cell examination. Testicular torsion-detorsion led to a significant decrease in the mean values of the Johnsen's scores and a significant increase in the apoptotic cell values of group B. There were no significant differences between group D and group A. In addition, the MDA and 8OHdG levels increased significantly in group B. The MDA and 8OHdG values were lower in group D. However, the 8OHdG levels were higher in group C than the groups A and D. On the other hand, CAPE suppresses mTOR activation and reduces the apoptosis on ischemia/reperfusion damage in rat testis. These results demonstrate that CAPE suppresses mTOR activation and reduces the apoptosis on ischemia/reperfusion damage in rat testis.

Prevention of posterior capsular opacification

Posterior capsular opacification (PCO) is a common complication of cataract surgery. The development of PCO is due to a combination of the processes of proliferation, migration, and transdifferentiation of residual lens epithelial cells (LECs) on the lens capsule. In the past decades, various forms of PCO prevention have been examined, including adjustments of techniques and intraocular lens materials, pharmacological treatments, and prevention by interfering with biological processes in LECs. The only method so far that seems effective is the implantation of an intraocular lens with sharp edged optics to mechanically prevent PCO formation. In this review, current knowledge of the prevention of PCO will be described. We illustrate the biological pathways underlying PCO formation and the various approaches to interfere with the biological processes to prevent PCO. In this type of prevention, the use of nanotechnological advances can play a role.

Caffeic acid phenethyl ester: its protective role against certain major eye diseases

As an effective compound found mainly in the honeybee product propolis, caffeic acid phenethyl ester (CAPE) has been commonly utilized as a medicine and remedial agent, in a number of countries. Specifically, it might inhibit nuclear factor kappa B at micromolar concentrations and demonstrate antioxidant, antineoplastic, antiproliferative, cytostatic, antiviral, antibacterial, antifungal, and anti-inflammatory features. This review article summarizes the recent progress regarding the favorable effects of CAPE on a number of eye disease models, including cataract and posterior capsule opacification, corneal diseases, retina and optic nerve-related diseases, ischemia/reperfusion injury of retina, inflammation and infection-related diseases. CAPE has been found to exhibit promising efficacy, with minimal adverse effects, in animal and cell culture studies of several eye diseases.

The protective effects of caffeic acid phenethyl ester against toluene-induced nephrotoxicity in rats

Caffeic acid phenethyl ester (CAPE) has antioxidant and anti-inflammatory properties. The aim of this study is to examine the negative effects of toluene on kidney tissues and functions and to investigate the protective effects of CAPE against toluene-induced nephrotoxicity in rats. A total of 21 male Wistar rats were divided into three groups of equal number in each. The rats in group I were the controls. Toluene was intraperitoneally injected into the rats in group II with a dose of 500 mg/kg. Rats in group III received CAPE daily while exposed to toluene. After 14 days of experimental period, all rats were killed by decapitation. Enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and malondialdehyde (MDA) levels were studied in the rat kidneys. Blood urea nitrogen (BUN) and serum creatinine levels were measured for renal function. The CAT and SOD enzyme activities and serum creatinine levels were significantly increased in rats treated with toluene when compared with the controls. But GSH-Px activity, MDA, and BUN levels showed statistically nonsignificant changes. However, increased CAT and SOD enzyme activities and decreased serum creatinine levels were detected in the rats that received CAPE while exposed to toluene. The GSH-Px activity and MDA and BUN levels in the same group did not show statistically significant changes. The results of our study demonstrated that toluene damages kidney tissue and is a nephrotoxic substance. CAPE was able to prevent the renal damage as antioxidant, antitoxic, and nephroprotective agent.

Modern cataract surgery: unfinished business and unanswered questions

We summarize information, based on clinicopathologic studies over the past decade, on various cataract intraocular lens (IOL) procedures and modern "specialized" IOLs, that will help surgeons continuously improve long-term results for cataract patients. Although most operations do initially provide excellent refractive correction and visual rehabilitation, late complications occur. These sometimes are missed because they are outside of the routine period of follow-up care. We have tried to determine if the various techniques and IOLs truly deliver the long-term results that we desire. Most safety and efficacy information is derived from the manufacturer and is passed through the U.S. Food and Drug Administration (FDA). This is often based on limited, relatively short-term observations made by the manufacturer. After a lens receives FDA approval, there are few means to assess the outcome of each procedure and lens years later. We rarely hear of a 10- or 20-year follow-up study. We have found that one of the best means to assess long-term results is pathologic analyses. We discuss recently studied aspects of pathologic reactions, such as posterior capsule opacification, intracapsular fibrosis, glistenings, intralenticular opacification, and other issues with the various IOL platforms; we then present a clinicopathological overview of tissues and IOLs from our database. These include hydrophobic and hydrophilic acrylic designs, plate lenses, and a dual optic lens.

Cytoskeletal drugs prevent posterior capsular opacification in human lens capsule in vitro

BACKGROUND

To determine whether the cytoskeletal drugs H-7 and Latrunculin B (LAT-B) inhibit posterior capsular opacification (PCO) in the cultured human lens capsular bag.

METHODS

Following extracapsular cataract (lens) extraction in human donor eyes, the capsular bag was prepared and cultured by standard techniques. Forty-eight capsular bags were studied, of which 13 were treated with H-7 (50, 100 or 300 μM), 12 with 1% BSS (vehicle of H-7), 11 with LAT-B (2, 5 or 10 μM), and 12 with 0.25% DMSO (vehicle of LAT-B). Forty out of the 48 capsular bags were from paired eyes of 20 donors, with one bag being treated with H-7/LAT-B and the other with BSS/DMSO for each pair, including 20 for the H-7-BSS protocol and 20 for the LAT-B-DMSO protocol. The medium with the cytoskeletal drug/vehicle was replaced every 3-4 days for 4 weeks. PCO was assessed daily using inverted phase-contrast microscopy, and scored on a 4-point scale.

RESULTS

In all cultures with BSS or DMSO, residual lens epithelial cells (LECs) on the anterior capsule migrated to and proliferated on the posterior capsule by 3-7 days, and apparent LEC growth on the posterior capsule with severe capsular wrinkling (PCO Grade 3) was seen by 2-3 weeks. When treated continuously with H-7 or LAT-B, the migration and proliferation of LECs and the capsular wrinkling were inhibited in a dose-dependent manner, with the inhibition being complete (PCO Grade 0) in the 300 μM H-7 (n = 8, p < 0.001) or 10 μM LAT-B culture (n = 3, p = 0.002).

CONCLUSION

H-7 and LAT-B dose-dependently inhibited PCO formation in the cultured human lens capsular bags, suggesting that cytoskeletal drugs might prevent PCO formation after surgery in the human eye.

Neuroprotective effects of caffeic acid phenethyl ester on experimental traumatic brain injury in rats

The aim of this study was to evaluate the therapeutic efficacy of caffeic acid phenethyl ester (CAPE) with an experimental traumatic brain injury (TBI) model in rats. Twenty-four adult male Sprague-Dawley rats were randomly divided into three groups of 8 rats each: control, TBI, and TBI + CAPE treatment. In TBI and TBI + CAPE treatment groups, a cranial impact was delivered to the skull from a height of 7 cm at a point just in front of the coronal suture and over the right hemisphere. Rats were sacrificed at 4 h after the onset of injury. Brain tissues were removed for biochemical and histopathological investigation. To date, no biochemical and histopathological changes of neurodegeneration in the frontal cortex after TBI in rats by CAPE treatment have been reported. The TBI significantly increased tissue malondialdehyde (MDA) levels, and significantly decreased tissue superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, but not tissue catalase (CAT) activity, when compared with controls. The administration of a single dose of CAPE (10 μmol/kg) 15 min after the trauma has shown protective effect via decreasing significantly the elevated MDA levels and also significantly increasing the reduced antioxidant enzyme (SOD and GPx) activities, except CAT activity. In the TBI group, severe degenerative changes, shrunken cytoplasma and extensively dark picnotic nuclei in neurons, as well as vacuolization indicating tissue edema formation. The morphology of neurons in the CAPE treatment group was well protected. The number of neurons in the trauma alone group was significantly less than that of both the control and TBI +CAPE treatment groups. The caspase 3 immunopositivity was increased in degenerating neurons of the traumatic brain tissue. Treatment of CAPE markedly reduced the immunoreactivity of degenerating neurons. TBI caused severe degenerative changes, shrunken cytoplasma, severely dilated cisternae of endoplasmic reticulum, markedly swollen mitochondria with degenerated cristae and nuclear membrane breakdown with chromatin disorganization in neurons of the frontal cortex. In conclusion, the CAPE treatment might be beneficial in preventing trauma-induced oxidative brain tissue damage, thus showing potential for clinical implications. We believe that further preclinical research into the utility of CAPE may indicate its usefulness as a potential treatment on neurodegeneration after TBI in rats.

The efficiency of CAPE on retardation of hepatic fibrosis in biliary obstructed rats

The aim of this study was to evaluate the possible protective effects of caffeic acid phenethyl ester (CAPE) against cholestatic oxidative stress and liver damage in the common bile duct ligated rats. A total of 18 male Sprague-Dawley rats were divided into three groups: control, bile duct ligation (BDL) and BDL + received CAPE; each group contain 6 animals. The rats in CAPE treated groups were given CAPE (10 μmol/kg) once a day intraperitoneally (i.p) for 2 weeks starting just after BDL operation. The changes demonstrating the bile duct proliferation and fibrosis in expanded portal tracts include the extension of proliferated bile ducts into lobules, inflammatory cell infiltration into the widened portal areas were observed in BDL group. Treatment of BDL with CAPE attenuated alterations in liver histology. The proliferating cell nuclear antigen and the activity of TUNEL in the BDL were observed to be reduced with the QE treatment. The application of BDL clearly increased the tissue hydroxyproline (HP) content, malondialdehyde (MDA) levels and decreased the antioxidant enzyme (superoxide dismutase (SOD), glutathione peroxidase (GPx)) activities. CAPE treatment significantly decreased the elevated tissue HP content, and MDA levels and raised the reduced of SOD, and GPx enzymes in the tissues. The data indicate that CAPE attenuates BDL-induced cholestatic liver injury, bile duct proliferation, and fibrosis. The hepatoprotective effect of CAPE is associated with antioxidative potential.

Protective effects of caffeic acid phenethyl ester on retinal ischemia/reperfusion injury in rats

PURPOSE

To investigate whether caffeic acid phenethyl ester (CAPE) has a protective effect on retinal ischemia/reperfusion (I/R) injury in rats, and to determine the possible antioxidant mechanisms.

METHODS

Seventy-six female Wistar rats were randomized evenly into Sham, I/R injury model (M group), model plus vehicle (MV), and model plus CAPE (MC) groups. Retinal ischemia/reperfusion injury was induced by increasing the intraocular pressure to 110 mmHg for 60 min. Rats in the MV and MC groups were injected with vehicle and CAPE (10 µmol/kg i.p.), respectively, before reperfusion and once a day for one or seven days after I/R. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the retinal tissues were determined 24 hr after I/R. Retinal cells apoptosis was detected 24 hr after I/R injury by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling staining. On day 7 after reperfusion, the electroretinogram (ERG) was recorded, and the retinal histology was examined and quantified using light microscopy.

RESULTS

CAPE significantly decreased the MDA levels and increased the activities of SOD, GSH-Px, and CAT in the retina compared with the ischemia group (p< 0.05). CAPE attenuated the I/R-induced apoptosis of retinal cells in the inner nuclear and ganglion cells of the rat retina. CAPE also suppressed the I/R-induced reduction in the a- and b-wave amplitudes of the ERG (p<0.05). The thickness of the entire retina, inner nuclear layer, and inner plexiform layer and the number of cells in the ganglion cell layer in the MC group were significantly greater than those in the M group (p<0.05).

CONCLUSIONS

CAPE can protect the rat retina from I/R injury by enhancing the antioxidation ability and inhibiting the apoptosis of retinal cells, which suggests that CAPE is potentially useful for treating I/R-induced eye disorders.

Polylactide-glycoli acid and rapamycin coating intraocular lens prevent posterior capsular opacification in rabbit eyes

OBJECTIVES

Posterior capsular opacification (PCO) is caused by the proliferation and migration of residual lens epithelium cells (LECs) after extracapsular cataract extraction (ECCE). Rapamcin (RAPA) is known to be a potent immunosuppressive drug with anti-inflammatory and anti-proliferative effects. The aim of this study was to investigate the safety and efficacy of rapamycin sustained release from modified intraocular lens (IOLs) in the prevention of PCO in rabbits.

METHODS

Three types of IOLs were used, including the original IOL without modification, IOL with polylactide-glycoli acid (PLGA) coating (PLGA-IOL), and RAPA-loaded PLGA-IOL (RAPA-PLGA-IOL). Sixty New Zealand albino rabbits undergoing phacoemulsification in left eyes were randomly and equally divided into three groups. Group A was implanted with the original IOLs, group B was implanted with the PLGA-IOLs, and group C was implanted with the RAPA-PLGA-IOLs. All of the 60 treated left eyes were examined by a slit-lamp microscope. The concentrations of RAPA in the aqueous humor and blood were determined by high-performance liquid chromatography (HPLC), indicating an vivo release of drug from the polymer carrier. Anterior segment tissue was histologically examined, and wet posterior capsules were weighed. Six months after intervention the PCO was graded.

RESULTS

The mean concentrations of RAPA in the aqueous humor from group C at 2 h, 1 days, 3 days, and 7 days after operation were 12.81 +/- 1.27 microg/ml, 14.57 +/- 0.99 microg/ml, 6.39 +/- 0.95 microg/ml, and 1.10 +/- 0.32 microg /ml respectively. The concentrations of RAPA in blood were undetectable. During the early days after the operation, the reactions of the anterior chamber from groups A and B were more severe than from group C. Our findings showed that the initial appearance of PCO in group C was much later than in the other two groups. The wet posterior capsules were weighed to be 0.3735 +/- 0.0943 g (group A), 0.3754 +/- 0.1093 g (group B), and 0.0432 +/- 0.0089 g (group C). Histological observation showed a similar phenomenon, that there was remarkably less accumulation of lens materials on the posterior capsules in group C than in the other two groups.

CONCLUSION

Our findings suggest that the designed RAPA-PLGA-IOL effectively prevented formation and development of PCO for a relatively long duration.

Prevention of posterior capsular opacification through aldose reductase inhibition

PURPOSE

The purpose of this study was to evaluate the effect of aldose reductase (AR) inhibition on posterior capsular opacification (PCO) with the use of a pig eye capsular bag model.

METHODS

Pig eye capsular bags were prepared by capsulorhexis and cultured in medium without or with AR inhibitors for 7 days. Immunostaining was performed in paraformaldehyde-fixed capsular bags to determine the expression of proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (SMA), beta-crystallin, and intercellular adhesion molecule (ICAM)-1. The effect of AR inhibition on basic fibroblast growth factor (BFGF)-induced mitogenic signaling in cultured human lens epithelial cells (HLECs) was examined. Cell growth was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and cell counting, the expression of alpha-SMA, beta-crystallin, and ICAM-1 by Western blot and immunocytochemical analysis, protein kinases by Western blot analysis, and NF-kappaB activation by gel shift and reporter assays.

RESULTS

During culture of pig eye capsular bags, residual cells on both the anterior and the posterior capsule showed vigorous growth. Treatment with AR inhibitors significantly prevented the lens epithelial cell growth in capsular bags and expression of alpha-SMA, beta-crystallin, and ICAM-1. HLECs showed a dose-dependent response to BFGF, proliferation at lower concentrations (<20 ng/mL) and differentiation/transdifferentiation at higher concentrations (>50 ng/mL). Inhibition of AR also prevented the BFGF-induced activation of ERK1/2, JNK, and NF-kappaB in HLECs.

CONCLUSIONS

Results suggest that AR is required for lens epithelial cell growth and differentiation/transdifferentiation in the capsular bags, indicating that inhibition of AR could be a potential therapeutic target in the prevention of PCO.

Effects of caffeic acid phenethyl ester on the histopathological changes in the lungs of cigarette smoke-exposed rabbits

We aimed at evaluating the effects of caffeic acid phenethyl ester (CAPE) on the histopathological changes in the lungs of rabbits exposed to cigarette smoke exposure. Four groups with six rabbits each were as follows: cigarette smoke group, CAPE group, cigarette smoke + CAPE group and control group. The cigarette smoke group was exposed to cigarette smoke 1 hr daily for 1 month. The CAPE group was administered intraperitoneal CAPE. The CAPE + cigarette smoke group was both exposed to cigarette smoke and was administered intraperitoneal CAPE. The control group was exposed to clean air. After 1 month, the rabbits were killed and the lung tissues were examined histopathologically. Peribronchial and intraparenchymal inflammation, intraparenchymal vascular congestion and thrombosis, intraparenchymal haemorrhage, respiratory epithelial proliferation, number of macrophages in the bronchiolar and alveolar lumen, alveolar destruction, emphysematous changes and bronchoalveolar haemorrhage scores were significantly higher in the cigarette smoke group than in the control group. Administration of CAPE to cigarette smoke-exposed rabbits significantly prevented all these changes. CAPE seems to have significant preventive effects on the severe histopathological changes in the lungs associated with cigarette smoke exposure. However, in some instances, it may not alter the progression to fibrosis.

Effect of caffeic acid phenethyl ester on treatment of experimentally induced methicillin-res??stantStaphylococcus epidermidis endophthalmitis in a rabbit model

This study investigated the anti-inflammatory effects of caffeic acid phenethyl ester (CAPE), a natural bee-produced compound, and compared it with corticosteroids in the treatment of experimentally induced methicillin-resistant Staphylococcus epidermidis (MRSE) endophthalmitis in addition to intravitreal antibiotics. An experimental endophthalmitis model was produced in 24 New Zealand albino rabbits by unilateral intravitreal injection of 0.1 ml of 4.7 x 10(4) colony-forming units (CFU) methicillin-resistant S. epidermidis. The animals were then divided randomly into three treatment groups and a control group, group 1 (six rabbits), received only intravitreal vancomycin (1.0 mg/0.1 ml); group 2 (six rabbits), received both intravitreal vancomycin (1.0 mg/0.1 ml) and intravitreal dexamethasone (400 microg/0.1 ml) and group 3 (six rabbits), received both intravitreal vancomycin (1.0 mg/0.1 ml) and subtenon CAPE (10 mg/0.3 ml) after 24 h post-infection. No treatment was given to the control group. Treatment efficacy was assessed by clinical examination, vitreous culture and histopathology. There were no statististically significant differences between clinical scores of all groups in examinations at 24 and 48 h post-infection (p = 0.915 and p = 0.067 respectively), but in examinations at 72 h post-infection and after 7 days post-infection, although the clinical scores of treatment groups were not significantly different from each other, they were significantly lower than the control group (p < 0.05). The culture results of all groups were sterile. As a result, CAPE was found to be as effective as dexamethasone in reducing inflammation in the treatment of experimental MRSE endophthalmitis when used with antibiotics. More studies are needed to determine the optimal administration route and effective dosage of this compound.

The effect of caffeic acid phenethyl ester on bacterial translocation and intestinal damage in cholestatic rats

We investigated the effect of caffeic acid phenethyl ester in rat ileum injury induced by chronic biliary obstruction. Swiss albino rats were divided into three groups: Group 1, sham (n = 7); Group 2, common bile duct ligation (n = 7); and Group 3, common bile duct ligation plus caffeic acid phenethyl ester (n = 7). In the caffeic acid phenethyl ester-treated rats, ileum tissue levels of malondialdehyde and myeloperoxidase were significantly lower than those of the bile duct-ligated rats (P < 0.001). The levels of tumor necrosis factor-alpha, interleukin-6, and interleukin-1alpha in the caffeic acid phenethyl ester group were significantly lower than those in the bile duct ligation group (P < 0.03, P < 0.01, and P < 0.02 respectively). The present study demonstrates that intraperitoneal administration of caffeic acid phenethyl ester in bile duct-ligated rats reduces intestinal oxidative stress. This effect may be useful in the preservation of intestinal damage in cholestasis.

Role of caffeic acid phenethyl ester, an active component of propolis, against NAOH-induced esophageal burns in rats

OBJECTIVES

This study was evaluated to investigate the efficacy of caffeic acid phenethyl ester (CAPE), which is a natural honeybee product exhibits a spectrum of biological activities including anti-microbial, anti-inflammatory, antioxidant and anti-tumoral actions, on the prevention of stricture development after esophageal caustic injuries in the rat.

METHODS

Thirty healthy male Wistar albino rats were utilized in this study. The rats were randomly allotted into one of three experimental groups: group A (sham) animals were uninjured. Caustic esophageal burn was created by applying 1 ml 37.5% NaOH to the distal esophagus. Group B rats were injured but untreated. Group C rats were injured and received CAPE (10 micromol/kg/day i.p. for 28 days). Efficacy of the treatment was assessed by measuring the esophageal transit time, stenosis index, histopathologic damage score and biochemically by determining tissue hydroxyproline content, lipid peroxidation and antioxidant enzyme activities.

RESULTS

The esophageal transit time, the stenosis index, histopathologic damage score and the hydroxyproline level were significantly increased in the untreated group compared with the sham and CAPE-treated groups. Treatment with CAPE decreased tissue hydroxyproline levels, histological damage, and the stenosis index, but except the esophageal transit time. Caustic esophageal burn also increased the lipid peroxidation and decreased the antioxidant enzyme activities in the untreated group. CAPE treatments decreased the elevated lipid peroxidation and also increased the reduced antioxidant enzyme activities. In corrosive esophageal burn group with no treatment, the most consistent findings were degenerative changes and increased in submucosal collagen content, and the luminal narrowing. CAPE treatment protected esophagus. Nevertheless, there was the slight increase in submucosal collagen.

CONCLUSIONS

It is concluded that CAPE has a preventive effect on the stricture development after esophageal caustic injuries in the rat.

Protective effects of melatonin and caffeic acid phenethyl ester against retinal oxidative stress in long-term use of mobile phone: A comparative study

There are numerous reports on the effects of electromagnetic radiation (EMR) in various cellular systems. Melatonin and caffeic acid phenethyl ester (CAPE), a component of honeybee propolis, were recently found to be potent free radical scavengers and antioxidants. Mechanisms of adverse effects of EMR indicate that reactive oxygen species may play a role in the biological effects of this radiation. The present study was carried out to compare the efficacy of the protective effects of melatonin and CAPE against retinal oxidative stress due to long-term exposure to 900 MHz EMR emitting mobile phones. Melatonin and CAPE were administered daily for 60 days to the rats prior to their EMR exposure during our study. Nitric oxide (NO, an oxidant product) levels and malondialdehyde (MDA, an index of lipid peroxidation), were used as markers of retinal oxidative stress in rats following to use of EMR. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status in retinal tissue. Retinal levels of NO and MDA increased in EMR exposed rats while both melatonin and CAPE caused a significant reduction in the levels of NO and MDA. Likewise, retinal SOD, GSH-Px and CAT activities decreased in EMR exposed animals while melatonin and CAPE caused a significant increase in the activities of these antioxidant enzymes. Treatment of EMR exposed rats with melatonin or CAPE increased the activities of SOD, GSH-Px and CAT to higher levels than those of control rats. In conclusion, melatonin and CAPE reduce retinal oxidative stress after long-term exposure to 900 MHz emitting mobile phone. Nevertheless, there was no statistically significant difference between the efficacies of these two antioxidants against to EMR induced oxidative stress in rat retina. The difference was in only GSH-Px activity in rat retina. Melatonin stimulated the retinal GSH-Px activity more efficiently than CAPE did.

Caffeic acid phenethyl ester preferentially sensitizes CT26 colorectal adenocarcinoma to ionizing radiation without affecting bone marrow radioresponse

PURPOSE

Caffeic acid phenethyl ester (CAPE), a component of propolis, was reported capable of depleting glutathione (GSH). We subsequently examined the radiosensitizing effect of CAPE and its toxicity.

METHODS AND MATERIALS

The effects of CAPE on GSH level, GSH metabolism enzyme activities, NF-kappaB activity, and radiosensitivity in mouse CT26 colorectal adenocarcinoma cells were determined. BALB/c mouse with CT26 cells implantation was used as a syngeneic in vivo model for evaluation of treatment and toxicity end points.

RESULTS

CAPE entered CT26 cells rapidly and depleted intracellular GSH in CT26 cells, but not in bone marrow cells. Pretreatment with nontoxic doses of CAPE significantly enhanced cell killing by ionizing radiation (IR) with sensitizer enhancement ratios up to 2.2. Pretreatment of CT26 cells with N-acetyl-L-cysteine reversed the GSH depletion activity and partially blocked the radiosensitizing effect of CAPE. CAPE treatment in CT26 cells increased glutathione peroxidase, decreased glutathione reductase, and did not affect glutathione S-transferase or gamma-glutamyl transpeptidase activity. Radiation activated NF-kappaB was reversed by CAPE pretreatment. In vivo study revealed that pretreatment with CAPE before IR resulted in greater inhibition of tumor growth and prolongation of survival in comparison with IR alone. Pretreatment with CAPE neither affected body weights nor produced hepatic, renal, or hematopoietic toxicity.

CONCLUSIONS

CAPE sensitizes CT26 colorectal adenocarcinoma to IR, which may be via depleting GSH and inhibiting NF-kappaB activity, without toxicity to bone marrow, liver, and kidney.

Excessive maternal caffeine exposure during pregnancy is cataractogenic for neonatal crystalline lenses in rats: a biomicroscopic and histopathologic study

PURPOSE

To investigate histologically the influence of maternal caffeine exposure during pregnancy in vivo on crystalline lenses in neonatal rats.

METHODS

Experimentally naive, female Wistar-albino rats (200-220 g) were mated with adult male rats over 2 days for copulation. After confirming pregnancy with a vaginal smear method, 50 gravid rats (dams) were randomly divided into five groups (n = 10 in each), consisting of one control and four experimental groups. Groups 1, 2 and 3 experimental dams were treated with intraperitoneal (i.p.) caffeine at doses of 25, 50 and 100 mg/kg/day, respectively, during pregnancy from gestational day 9 through to day 21. Group 4 dams were treated with caffeine in distilled water in a gavage at a dose of 50 mg/kg/day. Group 5 control dams were given i.p. saline solution daily for the same period. After normal delivery, the eyes were examined by slit-lamp biomicroscopy. The neonates were then killed by decapitation at postnatal days 1 or 30 and the eyes removed for histopathologic investigation of the lenses.

RESULTS

Group 1 and control eyes had normal anterior lens capsules with a single layer of anterior cuboidal epithelial cells, regularly oriented cortical and nuclear lens fibres, and a clear posterior lens capsule with no lining epithelial cells behind the equator. In the remaining groups, histopathologic findings suggesting cataractogenesis included eosinophilic degeneration, lens fibre cell swelling and liquefaction, central lens fibres with retained nuclei, and prominent epithelial cells lining the posterior lens capsule behind the equator. Moreover, some lenses in group 3 had immature cataract on slit-lamp biomicroscopic examination at postnatal day 30.

CONCLUSION

Excessive maternal caffeine exposure during pregnancy had cataractogenic effects on developing crystalline lenses in newborn rat eyes, both macroscopically and histopathologically. If an appropriate dose of caffeine can be identified, caffeine-induced cataract formation may be used as a new experimental cataract model in animal studies.

Caffeic acid phenethyl ester ameliorated ototoxicity induced by cisplatin in rats

Caffeic acid phenethyl ester (CAPE), an active component of propolis, exhibits antioxidant properties. This experimental study was designed to determine the effect of CAPE on ototoxicity induced with cisplatin. Twenty-four adult Wistar albino rats were divided into four groups: cisplatin (n=6), saline (n=6), CAPE (n=6), and cisplatin plus CAPE (n=6). Rats were tested before and 5 days after cisplatin treatment with or without chemo protection. The Distortion Product Otoacoustic Emissions (DPOAEs) were elicited from the control and experimental animals utilizing the standard commercial Otoacoustic Emission (OAEs) apparatus. The animals in all groups were sacrificed under general anesthesia on the fifth day following last OAE measurements. For biochemical investigations, the blood samples were drawn from inferior vena cava. On day 0, the initial baseline DPOAEs measurement results presented similar values while comparing the groups in drug free phase (p>0.05). On day 5, intrasubject measurement parameters of DPgrams and I/O functions of cisplatin group were significantly deteriorated (p<0.05). The second measurements of the other groups revealed no significant differences between their DPgrams and I/O functions in all frequencies (p>0.05). Among the biochemical parameters, plasma xanthine oxidase (XO) activity was found to be more elevated in the cisplatin group than the saline group (p<0.05). CAPE led to more decreased XO activity than cisplatin (p<0.05). The results of this study show that prophylactic administration of CAPE for cisplatin ototoxicity ameliorated hearing deterioration in rats.

Methods of assessment of patients for Nd:YAG laser capsulotomy that correlate with final visual improvement

BACKGROUND

This paper attempts to clarify the usefulness of various simple pre-operative measures in estimating the potential for a visually successful capsulotomy.

METHODS

24 patients attending for capsulotomy had pre-operative measures of glare with BAT tester, visibility of posterior pole and grading of posterior capsular pearls and fibrosis seen at slit lamp. Visual function was measured before and after standardised capsulotomy. Correlations of the various preoperative measures with eventual visual function improvements were calculated.

RESULTS

Pearls at slit lamp and poor posterior pole visualisation were all correlated with improvements in visual acuity and contrast sensitivity after capsulotomy. Amount of fibrosis visible at slit lamp and glare assessment were not correlated with vision improvements after laser.

CONCLUSION

Of the various measures that are taken prior to Nd : YAG capsulotomy, some correlate with eventual visual improvement but for others no clinical utility was found. Practitioners should note these findings as they are especially of use in more questionable or high-risk cases to help determine whether referral for PCO treatment by Nd: YAG capsulotomy is likely to benefit the patient.

Protective role of alpha-tocopherol and caffeic acid phenethyl ester on ischemia-reperfusion injury via nitric oxide and myeloperoxidase in rat kidneys

BACKGROUND

The aim of this study was to determine the acute effects of antioxidant caffeic acid phenethyl ester (CAPE) and alpha-tocopherol (vitamin E) on nitric oxide (NO) production, neutrophil infiltration, and antioxidant enzyme activities on an in vivo model of renal ischemia-reperfusion injury.

METHODS

Rats were divided into five equal groups each consisting six rats: sham operation, ischemia, ischemia-reperfusion (I/R), I/R plus CAPE, and I/R plus vitamin E groups. CAPE or vitamin E was administered intraperitoneally before reperfusion. After experimental procedure, rats were sacrificed and both ipsilateral and contralateral kidneys were removed and prepared for NO concentrations, myeloperoxidase (MPO), catalase (CAT) and superoxide dismutase (SOD) activities.

RESULTS

Acute administration of vitamin E decreased NO concentrations in both ipsilateral and contralateral renal tissues compared to I/R group. SOD activity was increased in I/R and I/R + CAPE groups compared to sham operation group. The most prominent results were encountered in MPO activities, which did not change in contralateral kidneys in both ischemia and I/R groups. There was a significant decrease in ipsilateral MPO activity in ischemia group and a significant increase in I/R group compared to sham operation group. Pretreatment with intraperitoneal CAPE significantly diminished the tissue MPO activity indicating the prevention of the neutrophil sequestration into the kidney.

CONCLUSION

There is a role for CAPE in attenuation in renal damage after I/R injury of the kidney, in part at least by inhibition of neutrophil sequestration.

Inhibitory effect of caffeic acid phenethyl ester on bleomycine-induced lung fibrosis in rats

BACKGROUND

Pulmonary fibrosis (PF) induced by anticancerogenic bleomycin (BLM) is one of the more common side effects encountered during cancer treatment. It has been suggested in the last decades that the main responsible agent in PF is reactive oxygen species which were generated also in normal physiological conditions in the human body. In this experimental study, we investigated the preventive or attenuating effects of caffeic acid phenethyl ester (CAPE) that has been demonstrated to have anti-inflammatory, cytocytatic, anticancerogenic, antiprolipherative and antioxidant effects on BLM-induced PF.

METHODS

Thirty-six Sprague-Dawley rats were divided randomly into four groups as sham operation, BLM, BLM + vitamin E (vit E), and BLM + CAPE groups. BLM (7.5 mg/kg, single dose) was applied intratracheally, and CAPE and vit E intraperitoneally in the appropriate groups. At the end of the fibrosis processes, lung tissues were removed and the levels of tissues hydroxyproline (OH-proline), malondialdehyde (MDA) and NO as well as the activities of superoxide dismutase (SOD), catalase (CAT) and myeloperoxidase (MPO) were determined. Also, the weights of the rats were recorded at 7th and 14th days of the experiments.

RESULTS

BLM application to the rats resulted in a significant increase in the OH-proline level as compared to the controls. Administration of CAPE and vit E led to the remarkable reduction of total lung OH-proline levels compared to the rats treated with BLM alone (p < 0.0001). There were a decreases in antioxidant enzyme (SOD and CAT) activities while an increase in MPO activity in BLM group was found vs. the control group (p < 0.0001). CAPE had a regulator effect on these parameters: the increase in CAT and SOD activities and the decrease in MPO activity were seen after CAPE application. NO, MDA and OH-proline levels were increased in BLM group vs. the control group. CAPE was more effective in decreasing the tissue levels of NO, MDA and OH-proline than vit E. MPO activity, as a good marker of neutrophil sequestration to the tissues, in the BLM group was decreased by CAPE approximately to the control group.

CONCLUSION

We suggest that CAPE is more effective on the prevention of BLM-induced fibrosis via antioxidant and free radical scavenger properties than vit E at the doses used in the present study. CAPE has some attenuating effects on BLM-induced PF affecting both oxidant and antioxidant systems as well as neutrophils sequestration.

Pharmacologic prevention of posterior capsule opacification: in vitro effects of preservative-free lidocaine 1% on lens epithelial cells

PURPOSE

To assess the in vitro effectiveness of preservative-free lidocaine 1% in removing lens epithelial cells (LECs) from the anterior capsule and to evaluate the effect of lidocaine on the LECs.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Eight rabbits (16 eyes) were used in the study. After the rabbits were killed, the eyes were enucleated and divided into 2 groups. In Group 1 (n = 8 eyes), LECs were exposed to preservative-free lidocaine 1% or balanced salt solution (BSS) for 1, 2, or 5 minutes. The anterior capsules were then stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken and analyzed for LEC damage. In Group 2 (n = 8 eyes), hydrodissection was performed with 1 of the agents, followed by phacoemulsification and cortical cleanup. The LEC attachment to the anterior capsule was evaluated by histopathology.

RESULTS

Anterior capsule fragments irrigated with BSS showed no LEC nuclear staining; ie, no direct toxic effect. In those irrigated with preservative-free lidocaine 1%, the LECs showed mild toxicity; some cells showed blue nuclear staining. After hydrodissection with lidocaine, the capsules were almost free of LECs; after hydrodissection with BSS, the capsules showed a normal layer of LECs attached to the anterior capsule.

CONCLUSIONS

Preservative-free lidocaine 1% may help diminish the amount of live LECs by facilitating cortical cleanup, by loosening the desmosomal area of cell-cell adhesion with decreased cellular adherence, or by a direct toxic effect. The use of this agent may help prevent posterior capsule opacification.

Lens epithelial cells express CD95 and CD95 ligand treatment induces cell death and DNA fragmentation in vitro

PURPOSE

Despite advances in intraocular lens design and material, posterior capsule opacification remains one of the major problems in modern cataract surgery. Therefore, the use of antiproliferative agents has been advocated. CD95 ligand (CD95L, Fas, Apo-1) is a death ligand that triggers apoptosis in susceptible target cells. Apoptosis allows for the safe disposal of cells without damaging the surrounding tissue. The goal of this study was to characterize and evaluate CD95L-induced cell death in cultured lens epithelial cells (LEC).

METHODS

Expression of CD95 in untreated porcine LEC was investigated by flow cytometry. Cell death after CD95L or CD95 agonistic antibody treatment was assessed by crystal violet assay and DNA fragmentation was measured by comet assay.

RESULTS

The presence of CD95 was observed in LEC. CD95L treatment resulted in a time--and concentration-dependent killing of LEC, which was synergistically enhanced by the addition of cyclohexamide. CD95L treatment induced DNA fragmentation.

CONCLUSIONS

The present study confirms the use of apoptosis-inducing CD95L in the inhibition of LEC proliferation. Further studies are needed before clinical application of CD95L to inhibit posterior capsule opacification will be feasible.

Systems of analysis of posterior capsule opacification

This paper demonstrates the wide variety of systems for the analysis of posterior capsular opacification (PCO). No single system has been proved to be a gold standard and it is difficult to comment on the advantages of one system over another with the limited current knowledge on the effects of PCO on vision. There are few studies that actually compare the different systems of analysis. Researchers must ensure that the systems they use for PCO analysis are objective and must give maximum consideration to ensuring potential systematic errors are reduced to a minimum. Further research is required into how the various types and locations of PCO affect vision and how well different systems of analysis perform.

Use of caffeic acid phenethyl ester to prevent sodium-selenite-induced cataract in rat eyes

PURPOSE

To investigate whether caffeic acid phenethyl ester (CAPE) prevents sodium-selenite-induced cataract.

SETTING

Department of Ophthalmology and Biochemistry, Inonu University Medical Faculty, Turgut Ozal Medical Center, Research Hospital, Malatya, Turkey.

METHODS

Sixty Sprague-Dawley rat litters were randomized into 3 groups. In Group 1 (n = 18), sodium selenite (30 nmol/g body weight) was injected subcutaneously on postpartum day 10. In Group 2 (n = 22), subcutaneous CAPE (15 micromol/kg) and sodium selenite (30 nmol/g body weight) were injected on postpartum day 10. The CAPE dose was continued subcutaneously for 3 days after the initial injection. Only subcutaneous saline was injected in Group 3 (control, n = 20). The development of cataract was assessed weekly, and its density was graded by slitlamp biomicroscopy and photography. Removed rat lenses were analyzed for glutathione (GSH) and malondialdehyde (MDA, marker of lipid peroxidation).

RESULTS

Group 2 rats had clear lenses or minor cataract. All Group 1 rats developed more severe cataract or complete opacification. The between-group difference was statistically significant (P <.05). All control lenses (Group 3) were clear. The mean GSH level in Group 1 (4.49 micromol/g wet weight +/- 0.93 [SD]) was significantly lower than that in Group 2 (8.63 +/- 0.88 micromol/g wet weight) (P <.05) and controls (10.76 +/- 1.97 micromol/g wet weight) (P <.05). The mean MDA level in Group 1 (8.54 +/- 1.31 nmol/g wet weight) was significantly higher than that in Group 2 (5.23 +/- 0.84 nmol/g wet weight) (P <.05) and controls (4.19 +/- 0.81 nmol/g wet weight) (P <.05).

CONCLUSIONS

Caffeic acid phenethyl ester effectively suppressed cataract formation in rats. The protective effect was supported by lower GSH and higher MDA levels in Group 1 than in Group 2, suggesting the antioxidant efficacy of this agent. Since CAPE has no known harmful effect on normal cells, it may be beneficial in clinical use in humans.

Recent progress in pharmacological research of propolis

Propolis is a resinous hive product collected by honeybees from various plant sources. It is a popular folk medicine possessing a broad spectrum of biological activities. It has also been used as a health drink in various Asian, European and American countries. Several groups of researchers have focused their attention on the biological activity of propolis and its active principles. Many scientific articles are published every year in different international journals related to the pharmacological properties of propolis. This review article compiles recent findings (since 1995) on the pharmacological properties of propolis focusing on its antihepatotoxic, antitumour, antioxidative, antimicrobial and antiinflammatory properties. The possible mechanism of action of propolis as well as the active compounds are discussed.

Effects of caffeic acid phenethyl ester and epidermal growth factor on the development of caustic esophageal stricture in rats

BACKGROUND/PURPOSE

An experimental study was performed to modify the healing response in caustic esophageal burns to prevent stricture development. Two different agents with different modes of actions, caffeic acid phenethyl ester (CAPE) and epidermal growth factor (EGF), were studied. CAPE has antiinflammatory, immunomodulatory, antioxidant, and antimitotic properties. EGF has known properties in supporting wound healing and in protecting esophagus from injuries.

METHODS

The model described by Gehanno and its modification by Liu was used to create standard esophageal burns with 50% NaOH. The study was performed with 76 rats in 4 main groups (sham, CAPE, EGF, and control) and 2 subgroups in each for 5 and 28 days of observation. Efficacy of treatment was assessed in 28-day subgroups by measuring weight gain, contrast esophagograms on day 27, histologic evaluation by measuring stenosis index (wall thickness/lumen diameter), and collagen deposition, and biochemically by determining tissue hydroxy proline (OHP) content.

RESULTS

In the end of the study, increase rates of mean body weights of the animals in the 28-day subgroups were as follows: sham, 30%; CAPE, 23%; EGF, 22%; and control, 14%. Although all the animals in subgroups significantly gained weight, the mean weight gain was significantly low in controls when compared with sham, CAPE, and EGF groups (P <.05). Contrast esophagograms on day 27 showed no stenosis in the sham, mild stenosis in CAPE and EGF, and severe stenosis with proximal dilatation in controls. Stenosis indices of the subgroups were as follows: sham, 0.29; CAPE, 0.41; EGF, 0.41; control, 0.84. Index was significantly higher in controls (P <.05). Collagen accumulation scores in the esophageal wall were as follows: Sham, 0.0; CAPE, 0.87; EGF, 0.30; control, 2.70. Scores also were significantly higher in controls (P <.05). Tissue (OHP) levels were as follows (mg/g dry tissue): Sham, 1.48; CAPE, 1.53; EGF, 1.90; control, 4.01. Production of OHP was significantly higher in controls.

CONCLUSIONS

The results of the parameters in the study indicate that administration of CAPE and EGF has beneficial effects in the prevention of caustic esophageal strictures. Those effects of CAPE may occur through its antiinflammatory, immunomodulatory, and antioxidant properties, and EGF may occur through its induced proliferative properties on the esophagus.

Prevention of posterior capsule opacification by intraoperative single-dose pharmacologic agents

PURPOSE

To determine whether an intraoperative single dose of dexamethasone, diclofenac, ethylenediaminetetraacetic acid (EDTA), a combination of EDTA and RGD peptide (arginine-glycin-aspartic acid sequence), or mitomycin-C (MMC) is a pharmacological means of preventing or reducing the development of posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Celal Bayar University, School of Medicine, Manisa, and Department of Pathology, Dokur Eylül University, School of Medicine, Izmir, Turkey.

METHODS

Fifty-four rabbits were randomly divided into 6 groups. Dexamethasone (4 mg/cc), diclofenac (2.5 mg/cc), EDTA (8 mg/cc), a combination of EDTA and RGD peptide (2.5 mg/cc), or MMC (0.04 mg/cc) was given, 0.1 cc by hydrodissection and 0.9 cc into the capsular bag after phacoemulsification. The sixth group served as a control group. After 3 months, the PCO was graded clinically and the proliferation of lens epithelial cells (LECs) was evaluated histologically.

RESULTS

The drugs were significantly effective in preventing PCO compared with the control (P <.005). Dexamethasone had a weaker effect than the other drugs. In histological analysis, although monolayer LECs in the dexamethasone and diclofenac groups were observed, there was no proliferative activity on the posterior capsules in the EDTA, EDTA+RGD, and MMC groups in contrast to the multilayer cells in the control.

CONCLUSIONS

Intraoperative single-dose application of EDTA, EDTA+RGD peptide combination, and MMC significantly prevented the development of PCO in rabbit eyes. Diclofenac was less effective but also reduced PCO. Although dexamethasone did not prevent the proliferation of LECs, it decreased PCO clinically.

Surgical prevention of posterior capsule opacification. Part 2: Enhancement of cortical cleanup by focusing on hydrodissection

PURPOSE

To experimentally analyze the role and efficacy of hydrodissection in achieving maximal cortical cleanup.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Phacoemulsification and irrigation/aspiration were performed in 10 pairs of human eyes (20 eyes) obtained postmortem. Ten eyes had previous hydrodissection and 10 eyes, no hydrodissection. The time (seconds) required for complete lens substance removal in each procedure was measured. In addition, a qualitative evaluation of difficulty of surgery was noted.

RESULTS

Phacoemulsification required 28.6% less time in eyes with previous hydrodissection than in those without. Irrigation/aspiration time was reduced by 50.9% when hydrodissection was performed. The total time of each procedure required for complete evacuation of the capsular bag was reduced by an average of 37.7% in eyes with hydrodissection. Furthermore, qualitatively the procedure was far easier, less stressful, and caused less posterior capsule stress or rupture when copious hydrodissection was performed.

CONCLUSIONS

Hydrodissection enhances the general safety and efficiency of cortical cleanup, especially at 12 o'clock. Hydrodissection is the best available, practical, immediately implementable, and inexpensive means to help remove equatorial E-cells and thus alleviate the incidence of posterior capsule opacification.

Retrovirus-mediated transfer of a suicide gene into lens epithelial cells in vitro and in an experimental model of posterior capsule opacification

PURPOSE

The most common complication of cataract surgery is the development of posterior capsule opacification (PCO). Hyperplasia of the lens epithelium is one of the main cellular events following phacoemulsification and was found to be an important feature contributing to opacification of the posterior capsule. We investigated the feasibility of killing the residual lens epithelial cells by retroviral-mediated transfer of the herpes simplex virus-thymidine kinase (HSV-tk) gene, a well-studied suicide gene, into rabbit lens epithelial cells followed by ganciclovir (GCV) treatment.

METHODS

The capacity of retroviral vectors to transfer genes into rabbit lens epithelial cells was determined either in vitro (culture of rabbit lens epithelial cells) or in vivo (experimental model of PCO in rabbits) using cDNA encoding the beta-galactosidase (LacZ) reporter gene. To evaluate the efficiency of suicide gene therapy (infection with retroviral vectors encoding the HSV-tk gene followed by GCV treatment) we determined the sensitivity of HSV-tk infected lens epithelial cells to different concentrations of GCV in vitro. Then, in an experimental model of PCO, rabbits were treated with HSV-tk retroviral vectors at the end of the surgery and they received repeated intracameral and intravitreal injections of GCV at the concentration determined by the in vitro experiments.

RESULTS

Infection efficiency using LacZ retroviral vectors was about 29% in vitro and 10% in vivo. After infection of the HSV-tk cDNA in vitro, the cell killing effect of GCV was evaluated. A significant enhancement (four- to five-fold) of the cell sensitivity to GCV was shown in FLY-DFGtk as compared with mock infected (P < 0.01) cells even without selection of the HSV-tk positive cells. The GCV concentration leading to 50% reduction in cell number (IC50) was 50 microg/ml. In vivo infection with a HSV-tk vector led to the tk gene transfer into lens epithelial cells. Despite this local HSV-tk gene expression, we could not prevent capsule opacification.

CONCLUSIONS

Lens epithelial cells were successfully infected both in vitro and in vivo by beta-galactosidase and HSV-tk genes via retroviral vectors. In vitro infected lens epithelial cells displayed a strong sensitivity to GCV treatment. In vivo, we could not prevent capsule opacification in the rabbit model, very likely due to the limited level of the HSV-tk gene expression. However, our results suggest that virus-mediated suicide gene therapy might be a feasible treatment strategy to prevent capsule opacification with a more powerful vector.

Caffeic acid phenethyl ester prevents intestinal reperfusion injury in rats

BACKGROUND/PURPOSE

Ischemia-reperfusion injury is encountered frequently in conditions that diminish intestinal blood flow. Caffeic acid phenethyl ester (CAPE), which is a specific component of the honeybee hive product propolis, exhibits potential antioxidant properties. This experimental study was designed to determine the effect of CAPE on ischemia-reperfusion injury in rat intestine.

METHODS

Fifty rats were divided into 5 groups; sham (SH), saline ischemia (SI), saline reperfusion (SR), CAPE ischemia (CI), and CAPE reperfusion (CR). Either CAPE, 10 micromol/kg, or saline was administered intraperitoneally 30 minutes before ischemia. Intestinal ischemia for 30 minutes and reperfusion for 60 minutes were applied. Ileum specimens were obtained to determine the tissue levels of malondialdehyde, superoxide dismutase, catalase, and histological changes.

RESULTS

Malondialdehyde levels in the CR group did not increase after reperfusion when compared with the CI group. However, statistically significant differences were observed between the SR and SI groups. Additional mucosal injury in the CR group when compared with the CI group was not observed. Whereas, there was a statistically significant increase in mucosal injury in the SR group. Reperfusion did not cause further injuries through both biochemical and histological parameters in the CR group.

CONCLUSIONS

Results of this study showed that prophylactic administration of CAPE in ischemic condition prevents reperfusion injuries by eliminating oxygen radicals and inhibiting polymorphonuclear leukocyte infiltration. CAPE may be useful in combating the diseases of oxidative stress.

Adenovirus-mediated suicide gene transduction: feasibility in lens epithelium and in prevention of posterior capsule opacification in rabbits

The most common complication of cataract surgery is the development of posterior capsule opacification (PCO). Hyperplasia of the lens epithelium is one of the main cellular events following phacoemulsification, and has been found to be an important feature contributing to opacification of the posterior capsule. Adenoviral vector-mediated transfer is a suitable method for transducing the herpes simplex virus thymidine kinase gene (HSV-tk) into proliferating cells, allowing for the selective killing of these cells by ganciclovir (GCV) treatment. To determine the potential of gene transduction for lens epithelial cells, we studied the transduction of rabbit lens epithelial cells with adenoviral vectors containing either the Escherichia coli beta-galactosidase (lacZ) gene or the HSV-tk gene in vitro and in vivo in an experimental model of PCO. The efficiency of lacZ gene transfer in rabbit lens epithelial cells was at least 95% both in vitro and in vivo. In vivo transduction with HSV-tk adenoviral vector followed by GCV treatment significantly inhibited the development of PCO (p<0.001). These results suggest that adenoviral vector-mediated transfer of HSV-tk into the proliferating lens epithelial cells is feasible and may provide a novel therapeutic strategy for PCO.

Capsular opacification after cataract surgery

Posterior-capsule opacification, by far the most common complication of primary cataract surgery, continues to stimulate important work toward understanding its causes, preventing it, and effectively treating it. Of special note here are a report by Koch and Kohnen that a combination of vitrectomy and posterior capsulorhexis is required to inhibit posterior-capsule opacification in pediatric patients; work by Nishi et al. toward the dream of replacing the cataractous lens with a flexible artificial lens, supported by the natural capsular bag; and methods by Tetz et al. and Pande et al. for precise quantification of posterior-capsule opacification.

Posterior capsule opacification. Part 1: Experimental investigations

Posterior capsule opacification (PCO) is the most frequent complication associated with decreased vision after cataract surgery. Previous methods of preventing PCO have not proven to be practical, effective, and safe for routine clinical procedure, but some novel concepts and methods have recently been developed. This 2-part review looks at clinical and experimental investigations of PCO, focusing on developments since 1992. Clinical aspects will be presented in a later issue. This paper addresses (1) in vitro models for PCO research; (2) pathophysiology and molecular biology of lens epithelial cells (LECs); (3) prevention of PCO. Of special interest are methods of culturing human LECs obtained by capsulotomy during cataract surgery, including those obtained with an intact capsular bag, to provide an in vitro model for investigating the pathophysiology of LECs; the effect of a sharp bend in the lens capsule that induces contact inhibition of migrating LECs; more specific inhibition of migrating LECs using an immunotoxin, b-FGF-saporin, or EDTA and RGD-peptides.