Safety and efficacy of nivolumab and standard chemotherapy drug combination in patients with advanced non-small-cell lung cancer: a four arms phase Ib study.

BACKGROUND: The human IgG4 monoclonal antibody nivolumab targets programmed cell death-1 (PD-1) and promotes antitumor response by blocking the interaction of PD-1 with its ligands. This single-center phase Ib study investigated the tolerability, safety, and pharmacokinetics of nivolumab combined with standard chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients who had stage IIIB without indication for definitive radiotherapy, stage IV, or recurrent NSCLC were eligible. Regimens were nivolumab 10 mg/kg + gemcitabine/cisplatin (arm A), pemetrexed/cisplatin (arm B), paclitaxel/carboplatin/bevacizumab (arm C), or docetaxel (arm D). Regimens A, B, and D were repeated every 3 weeks for up to four cycles and regimen C was repeated for up to six cycles; nivolumab alone (arm A), with pemetrexed (arm B), bevacizumab (arm C), or docetaxel (arm D) was continued every 3 weeks as maintenance therapy until disease progression or unacceptable toxicity. Dose-limiting toxicity (DLT) was evaluated during the first treatment cycle. RESULTS: As of March 2014, six patients were enrolled in each arm. The combination of nivolumab 10 mg/kg and chemotherapy was well tolerated. DLT was observed in only one patient in arm A (alanine aminotransferase increased). Select adverse events (those with a potential immunologic cause) of any grade were observed in six, four, six, and five patients in arms A, B, C, and D, respectively. Three, three, six, and one patient achieved partial response while median progression-free survival was 6.28, 9.63 months, not reached, and 3.15 months in arms A, B, C, and D, respectively. CONCLUSIONS: Combination of nivolumab 10 mg/kg and chemotherapy showed an acceptable toxicity profile and encouraging antitumor activity in patients with advanced NSCLC. CLINICAL TRIALS NUMBER: Japanese Pharmaceutical Information Center Clinical Trials Information (JapicCTI)-132071.

LEDGF gene silencing impairs the tumorigenicity of prostate cancer DU145 cells by abating the expression of Hsp27 and activation of the Akt/ERK signaling pathway.

Lens epithelium-derived growth factor (LEDGF) maintains survival pathways by augmenting the transcription of stress-response genes such as small heat-shock protein 27. Recently, aberrant expression of LEDGF was found in prostate cancer (PC). Herein, we showed that LEDGF overexpression upregulated Hsp27 in PC cells, DU145, PC-3 and LNCaP and promoted antiapoptotic pathways in PCs. We found that these cells had higher abundance of Hsp27, which was correlated with the levels of LEDGF expression. Transactivation assay in DU145 cells revealed that transactivation of Hsp27 was related to the magnitude of LEDGF expression. Silencing of LEDGF in DU145 cells abrogated Hsp27 expression and inhibited stimulated cell proliferation, invasiveness and migration. These cells were arrested in S and G2 phase, and failed to accumulate cyclin B1, and showed increased apoptosis. Furthermore, LEDGF-depleted DU145 cells displayed elevated Bax and cleaved caspase 9 expression and reduced levels of Bcl2, Bcl-(XL). The activated survival pathway(s), ERK1/2 and Akt, were selectively decreased in these cells, which characteristically have lower tumorigenicity. Conversely, the depleted cells, when re-overexpressed with LEDGF or Hsp27, regained tumorigenic properties. Collectively, results reveal the involvement of LEDGF-mediated elevated expression of Hsp27-dependent survival pathway(s) in PC. Our findings suggest new lines of investigation aimed at developing therapies by targeting LEDGF or its aberrant expression-associated stimulated antiapoptotic pathway(s).

Specificity protein, Sp1-mediated increased expression of Prdx6 as a curcumin-induced antioxidant defense in lens epithelial cells against oxidative stress.

Peroxiredoxin 6 (Prdx6) is a pleiotropic oxidative stress-response protein that defends cells against reactive oxygen species (ROS)-induced damage. Curcumin, a naturally occurring agent, has diversified beneficial roles including cytoprotection. Using human lens epithelial cells (hLECs) and Prdx6-deficient cells, we show the evidence that curcumin protects cells by upregulating Prdx6 transcription via invoking specificity protein 1 (Sp1) activity against proapoptotic stimuli. Curcumin enhanced Sp1 and Prdx6 mRNA and protein expression in a concentration-dependent manner, as evidenced by western and real-time PCR analyses, and thereby negatively regulated ROS-mediated apoptosis by blunting ROS expression and lipid peroxidation. Bioinformatic analysis and DNA-protein binding assays disclosed three active Sp1 sites (-19/27, -61/69 and -82/89) in Prdx6 promoter. Co-transfection experiments with Sp1 and Prdx6 promoter-chloramphenicol acetyltransferase (CAT) constructs showed that CAT activity was dramatically increased in LECs or Sp1-deficient cells (SL2). Curcumin treatment of LECs enhanced Sp1 binding to its sites, consistent with curcumin-dependent stimulation of Prdx6 promoter with Sp1 sites and cytoprotection. Notably, disruption of Sp1 sites by point mutagenesis abolished curcumin transactivation of Prdx6. Also, curcumin failed to activate Prdx6 expression in the presence of Sp1 inhibitors, demonstrating that curcumin-mediated increased expression of Prdx6 was dependent on Sp1 activity. Collectively, the study may provide a foundation for developing transcription-based inductive therapy to reinforce endogenous antioxidant defense by using dietary supplements.

Age-related cataracts and Prdx6: correlation between severity of lens opacity, age and the level of Prdx 6 expression.

BACKGROUND: Peroxiredoxin 6 (Prdx6), a new family of antioxidants, regulates gene expression and function by controlling reactive oxygen species, delays hereditary cataracts in rats and protects epithelial cells in the lens against oxidative stresses. AIM: To investigate the correlation between Prdx6 expression, age and the severity of lens opacity at the time of cataract surgery. METHODS: 88 cataractous eyes were examined at Fukui University Hospital, Fukui, Japan, between March 2007 and October 2007. The patient age at the time of surgery, and the subtype and severity of cataract as classified according to the modified version of the Lens Opacities Classification System version III (LOCSIII) were recorded, as well as the expression level of Prdx6 mRNA in their lenses. RESULTS: The expression of Prdx6 was found to be significantly negatively associated with age at the time of cataract surgery (p<0.047). A significant correlation was also found between a higher nuclear or cortical cataract score and lower expression of Prdx6 in patients under 70 years old. CONCLUSION: These findings suggest that oxidative stress contributes to nuclear cataract formation and that a local decrease in Prdx6 in cataractous lenses may indicate the initiation of age-related cataract formation.

Peroxiredoxin 6 delivery attenuates TNF-alpha-and glutamate-induced retinal ganglion cell death by limiting ROS levels and maintaining Ca2+ homeostasis.

Higher expression of reactive oxygen species (ROS) is implicated in neurological disorders. A major event in glaucoma, the death of retinal ganglion cells (RGCs), has been associated with elevated levels of glutamate and TNF-alpha in the RGCs' local microenvironment. Herein we show that the transduction of Peroxiredoxin 6 (PRDX6) attenuates TNF-alpha- and glutamate-induced RGC death, by limiting ROS and maintaining Ca2+ homeostasis. Immunohistochemical staining of rat retina disclosed the presence of PRDX6 in RGCs, and Western and real-time PCR analysis revealed an abundance of PRDX6 protein and mRNA. RGCs treated with glutamate and/or TNF-alpha displayed elevated levels of ROS and reduced expression of PRDX6, and underwent apoptosis. A supply of PRDX6 protected RGCs from glutamate and TNF-alpha induced cytotoxicity by reducing ROS level and NF-kappaB activation, and limiting increased intracellular Ca2+ influx. Results provide a rationale for use of PRDX6 for blocking ROS-mediated pathophysiology in glaucoma and other neuronal disorders.

Detection of human papillomavirus in pterygium and conjunctival papilloma by hybrid capture II and PCR assays.

AIM: To elucidate the putative role of human papillomavirus (HPV) infection in pterygium and conjunctival papilloma. METHODS: Hybrid capture II (HC-II) and polymerase chain reaction (PCR) assays were performed to detect HPV in pterygium (42 samples obtained from 40 patients) and conjunctival papilloma (8 samples from 6 patients). The amount of HPV DNA was evaluated by measurement of relative light units (RLUs) on a luminometer. RESULTS: All papilloma samples were positive for HPV DNA by PCR and HC-II. The RLU values for specimens of recurrent and re-recurrent papilloma were markedly higher than those for specimens of primary lesions. HPV was detected by PCR in 2 of 42 (4.8%) beta-globin-positive pterygium specimens, whereas HC-II showed that HPV was negative in all pterygium samples. CONCLUSIONS: Our results support the hypothesis that HPV DNA is associated with the pathogenesis of conjunctival papilloma, but not pterygium. RLU measurement by HC-II may serve as a marker for evaluating the activity of HPV in conjunctival tumours.

Acid-catalyzed rearrangement of aryl-substituted homobenzoquinone epoxides.

The BF3-catalyzed reactions of diphenyl-substituted and endo-monophenyl-substituted homobenzoquinone epoxides proceeded through a regioselective oxirane ring opening followed by participation of a pi-aryl transannular cyclization to give the tricyclic diketo alcohols. The conformationally semirigid ethano-bridged diphenyl-substituted homologues also provided similar diketo alcohols and the subsequent ring-expanded cycloheptenedione (via a subsequent 1,2-acyl migration associated with cyclopropane ring opening), depending on the methyl-substitution pattern of the quinone frame. However, the exo-monophenyl-substituted and the rigid biphenyl-2,2'-diyl-substituted homobenzoquinone epoxides essentially remained unchanged.

Up-regulation of P-glycoprotein expression by osmotic stress in rat sugar cataract.

P-glycoprotein (P-gp), a plasma membrane protein, is thought to function in the export of cytotoxic drugs and to act as a modulator of chloride channels that regulate cell volume in many cell types. P-gp has been shown to play a role in lens volume regulation and initiation of osmotic cataract. We investigated the lenticular expression levels of P-gp in galactose-fed rats, an experimental model of sugar cataract. P-gp was overexpressed in lenses from galactose-fed rats with cortical sugar cataract, and in rat lens epithelial cells cultured in high-glucose medium. However, application of aldose reductase (AR) inhibitor was able to reverse the changes in P-gp levels in the lenses of galactose-fed rats, confirming the role of AR and involvement of the polyol pathway in cataract formation. Our findings suggest that P-gp may be induced by AR over-expression and/or osmotic stress, thus playing a regulatory role in maintaining lenticular osmotic balance in sugar cataract.

Axial length, myopia, and the severity of lens opacity at the time of cataract surgery.

OBJECTIVE: To investigate the relationship between axial length, myopia of the eye, and the severity of lens opacity at the time of cataract surgery. METHODS: We retrospectively reviewed a consecutive series of 198 eyes of patients aged older than 50 years at Fukui University Hospital (Fukui, Japan) from June 2004 to December 2005. Patient age at the time of surgery, axial length, spherical equivalent, and the subtypes and severity of cataract (as classified according to the modification of the Lens Opacities Classification System, version III) were recorded. RESULTS: Axial length was significantly associated with age at the time of cataract surgery (P<.001). Regarding the severity of nuclear cataract, a significant correlation was seen between a higher score of nuclear cataract and longer axial length (P<.001). The relationship between the severity of nuclear cataract and spherical equivalent at the time of surgery showed a significant association between grading nuclear color and nuclear opalescence 4-6 and higher myopia (P<.001). CONCLUSION: An increase in axial length or myopia of the eye was associated with a lower mean age at the time of surgery and higher grade of nuclear cataract.

DNA binding domains and nuclear localization signal of LEDGF: contribution of two helix-turn-helix (HTH)-like domains and a stretch of 58 amino acids of the N-terminal to the trans-activation potential of LEDGF.

Lens epithelium derived growth factor (LEDGF), a nuclear protein, plays a role in regulating the transcription of stress-associated genes such as heat shock proteins by binding to consensus core DNA sequences nAGGn or nGAAn or their repeats, and in doing so helps to provide cyto-protection. However, additional information is required to identify the specific structural features of LEDGF involved in gene transcription. Here we have investigated the functional domains activating and repressing DNA-binding modules, by using a DNA binding assay and trans-activation experiments performed by analyzing proteins prepared from deletion constructs. The results disclosed the DNA-binding domain of N-terminal LEDGF mapped between amino acid residues 5 and 62, a 58 amino acid residue stretch PWWP domain which binds to stress response elements (STRE; A/TGGGGA/T). C-terminal LEDGF contains activation domains, an extensive loop-region (aa 418-530) with two helix-turn-helix (HTH)-like domains, and binds to a heat shock element (HSE; nGAAn). A trans-activation assay using Hsp27 promoter revealed that both HTH domains contribute in a cooperative manner to the trans-activation potential of LEDGF. Interestingly, removal of N-terminal LEDGF (aa 1-187) significantly enhances the gene activation potential of C-terminal LEDGF (aa 199-530); thus the N-terminal domain (aa 5-62), exhibits auto-transcriptional repression activity. It appears that this domain is involved in stabilizing the LEDGF-DNA binding complex. Collectively, our results demonstrate that LEDGF contains three DNA-binding domains, which regulate gene expression depending on cellular microenvironment and thus modify the physiology of cells to maintain cellular homeostasis.

Impaired homeostasis and phenotypic abnormalities in Prdx6-/-mice lens epithelial cells by reactive oxygen species: increased expression and activation of TGFbeta.

PRDX6, a member of the peroxiredoxins (PRDXs) family, is a key player in the removal of reactive oxygen species (ROS). Using targeted inactivation of the Prdx6 gene, we present evidence that the corresponding protein offsets the deleterious effects of ROS on lens epithelial cells (LECs) and regulates gene expression by limiting its levels. PRDX6-depleted LECs displayed phenotypic alterations and elevated alpha-smooth muscle actin and betaig-h3 expression (markers for cataractogenesis), indistinguishable from transforming growth factor beta (TGFbeta)-induced changes. Biochemical assays disclosed enhanced levels of ROS, as well as high expression and activation of TGFbeta1 in Prdx6-/- LECs. A CAT assay revealed transcriptional repression of lens epithelium-derived growth factor (LEDGF), HSP27, and alphaB-crystallin promoter activities in these cells. A gel mobility shift assay demonstrated the attenuation of LEDGF binding to heat shock or stress response elements present in these genes. A supply of PRDX6 toPrdx6-/- LECs reversed these changes. Based on the above data, we propose a rheostat role for PRDX6 in regulating gene expression by controlling the ROS level to maintain cellular homeostasis.

Gene expression profiling of diabetic and galactosaemic cataractous rat lens by microarray analysis.

AIMS/HYPOTHESIS: Osmotic and oxidative stress is associated with the progression and advancement of diabetic cataract. In the present study, we used a cDNA microarray method to analyse gene expression patterns in streptozotocin-induced diabetic rats and galactose-fed cataractous lenses. In addition, we investigated the regulation and interaction(s) of anti-oxidant protein 2 and lens epithelium-derived growth factor in these models. METHODS: To identify differential gene expression patterns, one group of Sprague-Dawley rats was made diabetic with streptozotocin and a second group was made galactosaemic. Total RNA was extracted from the lenses of both groups and their controls. Labelled cDNA was hybridised to Atlas Rat Arrays. Changes in gene expression level were analysed. Real-time PCR and western analysis were used to validate the microarray results. RESULTS: The expression of 31 genes was significantly modulated in hyperglycaemic lenses compared with galactosaemic lenses. Notably, transcript and protein levels of B-cell leukaemia/lymphoma protein 2 and nuclear factor-kappaB were significantly elevated in rat lenses at 4 weeks after injection of streptozotocin. At a later stage, mRNA and protein levels of TGF-beta were elevated. However, levels of mRNA for IGF-1, lens epithelium-derived growth factor and anti-oxidant protein 2 were diminished in streptozotocin-induced diabetic cataract. CONCLUSIONS/INTERPRETATIONS: These results provide evidence that progression of sugar cataract involves oxidative- and TGF-beta-mediated signalling. These pathways may promote abnormal gene expression in the hyperglycaemic and galactosaemic states and thus may contribute to the symptoms associated with these conditions. Since oxidative stress seems to be a major event in cataract formation, supply of anti-oxidant may postpone the progression of such disorders.

Polyol pathway-dependent osmotic and oxidative stresses in aldose reductase-mediated apoptosis in human lens epithelial cells: role of AOP2.

Aldose reductase (AR) has been implicated as a major contributor to the pathogenesis of diabetic cataracts. AR activation generates osmotic and oxidative stresses via the polyol pathway and induces cell death signals. Antioxidant protein 2 (AOP2) protects cells from oxidative stress. We investigated the effect of AR overexpression on polyol accumulation and on hyperglycemic oxidative stress and osmotic stress, as well as the effects of these stresses on human lens epithelial cell (hLEC) survival. hLECs overexpressing the AR became apoptotic during hyperglycemia and showed elevated levels of intracellular polyols. Glutathione and AOP2 levels were significantly decreased in these cells. Interestingly, supply of AOP2 and/or the AR inhibitor fidarestat protected the cells against hyperglycemia-induced death. Overexpression of AR increased osmotic and oxidative stresses, resulting in increased apoptosis in hLECs. Because AOP2 protects hyperglycemia-induced hLEC apoptosis, this molecule may have the potential to prevent hyperglycemia-mediated complications in diabetes.

Correlation between erythrocyte aldose reductase level and human diabetic retinopathy.

AIM: To examine the relation between aldose reductase (AR) and the development and progression of diabetic retinopathy by comparing the erythrocyte AR levels with the prevalence of diabetic retinopathy in NIDDM patients. METHODS: A clinic based cross sectional study was used. 611 NIDDM patients and 73 controls were enrolled. Erythrocyte AR levels were determined by ELISA. These AR levels were then correlated with patient age, duration of diabetes, and HbA(1c) levels. AR levels were also correlated with the prevalence of diabetic retinopathy in the entire NIDDM patient group and in three subgroups formed by separating the NIDDM patients by their duration of diabetes. The prevalence of diabetic retinopathy significantly increased with increased erythrocyte AR levels in patients with duration of diabetes of less than 10 years. A similar, but non-significant correlation between the prevalence of retinopathy and increased erythrocyte AR levels was observed in patients with diabetes duration of 10-20 and >/=20 years. RESULTS: The prevalence of diabetic retinopathy increased with increased erythrocyte AR levels in NIDDM patients with a duration of diabetes of less than 10 years. CONCLUSION: It was suggested that the inhibition of AR in patients with early NIDDM might be beneficial in reducing the development of diabetic retinopathy.

Transactivation of involucrin, a marker of differentiation in keratinocytes, by lens epithelium-derived growth factor (LEDGF).

Human involucrin (hINV), first appears in the cytosol of keratinocytes and ultimately cross-linked to membrane proteins via transglutaminase and forms a protective barrier as an insoluble envelope beneath the plasma membrane. Although the function and evolution of involucrin is known, the regulation of its gene expression is not well understood. An analysis of the hINV gene sequence, upstream of the transcription start site (-534 to +1 nt) revealed the presence of potential sites for binding of lens epithelium-derived growth factor (LEDGF); stress response element (STRE; A/TGGGGA/T) and heat shock element (HSE; nGAAn). We reported earlier that LEDGF activates stress-associated genes by binding to these elements and elevates cellular resistance to various stresses. Here, gel-shift and super-shift assays confirm the binding of LEDGF to the DNA fragments containing HSEs and STREs that are present in the involucrin gene promoter. Furthermore, hINV promoter linked to CAT reporter gene, cotransfected in human corneal simian virus 40-transformed keratinocytes (HCK), was transactivated by LEDGF significantly. In contrast, the activity of hINV promoter bearing mutations at the WT1 (containing HSE and STRE), WT2 (containing STRE) and WT3 (containing STRE) binding sites was diminished. In addition, in HCK cell over-expressing LEDGF, the levels of hINV mRNA and hINV protein are increased by four to five-fold. LEDGF is inducible to oxidants. Cells treated with 12-O-tetradecanoyl-phorbol-13-acetate (TPA), known to stimulate production of H(2)O(2), showed higher levels of LEDGF mRNA. Furthermore, our immunohistochemical studies revealed that hINV protein is found in the cytoplasm of HCK cells over-expressing LEDGF, but not detectable in the normal HCK cells or HCK cells transfected with vector. This regulation appears to be physiologically important, as over-expression of HCK with LEDGF increases the expression of the endogenous hINV gene and may provide new insight to understand the molecular mechanism of transcriptional regulation of this gene. LEDGF may play an important role in establishing an important barrier in corneal keratinocytes by maintaining epidermal turn-over rate, and protecting HCKs against stress.

Histologic examination of dislocated lenses.

PURPOSE: To examine histological changes resulting from dislocated and subluxated lenses. CASES: The subjects consisted of 16 patients (aged 52-89 years) who underwent total lens extraction for lens dislocation or subluxation in the Department of Ophthalmology at Fukui Medical University during the period between April 1991 and June 1998. There were 5 patients (6 eyes) with traumatic dislocation and 11 patients (11 eyes) with idiopathic dislocation. RESULT: Rupture of the cortical fibers and migration of the epithelial cells toward the posterior pole of the lens were more frequently noted in patients with traumatic dislocation than in the idiopathic group, and both findings were often simultaneously observed. Rupture of the cortical fibers was considered attributable to external pressure transmitted to the lens. CONCLUSION: We speculate that the concurrent migration and dislocation of the equatorial bow architecture toward the posterior pole was caused by inhibition of differentiation of the epithelial cells to fiber cells by external pressure on the equatorial region.

Biochemical and morphological changes during development of sugar cataract in Otsuka Long-Evans Tokushima fatty (OLETF) rat.

The relationship between the polyol pathway and sugar cataracts has been studied extensively using streptozotocin-induced diabetic rats and galactose fed rats as animal models for insulin-dependent diabetes mellitus (IDDM). In these models, sugar cataracts progress quickly, leading to rapid lenticular polyol accumulation in the early stages of cataract formation. In 1992, a new animal model of non-insulin-dependent diabetes mellitus (NIDDM), the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, was established. In the present study, we examined both biochemical and morphological changes in the lenses of the OLETF rats to determine whether these changes reflect those associated with diabetic cataract formation and to clarify their relationship with the polyol pathway. For the biochemical analysis, we measured the enzyme activity of aldose reductase (AR) and sorbitol dehydrogenase (SDH) and the sorbitol levels using 20, 40 and 60 week old OLETF or control Long-Evans Tokushima Otsuka (LETO) rats. Enzyme activities of AR and SDH, which were lower in 20 week old OLETF rats than in LETO rats, were increased in 60 week old OLETF rats. The lenticular sorbitol level of the OLETF rats was similar to the control level at 20 weeks of age, but it was markedly increased at 40 weeks of age, and slightly decreased at 60 weeks of age compared with rats at 40 weeks but not compared with controls. Slight lens fiber swelling was observed in the anterior and/or posterior subcapsular regions of 40 week old OLETF rats, accompanying elevated sorbitol level and slightly increased SDH activity in the lens. Swelling and liquefaction of lens fibers were observed in the subcapsular and supranuclear region of 60 week old OLETF rats, as well as decreased lenticular sorbitol, and markedly increased SDH activity compared with rats at 40 weeks. AR activity was also increased causing the elevation of sorbitol in lenses of OLETF rats during the early stages of cataract formation. Despite differences in the etiology of diabetes mellitus, the strain of rat and the rate of disease progression in the OLETF rat model compared with other diabetic models, the present results support the theory that the polyol pathway via AR is a factor in the development of sugar cataracts.

Quantitative monitoring of circulating Epstein-Barr virus DNA for predicting the development of posttransplantation lymphoproliferative disease.

Epstein-Barr virus (EBV)-DNA was quantitatively measured to assess posttransplantation virus reactivation by real-time polymerase chain reaction (PCR). In the first retrospective analysis of a 7-year-old boy with lymphoproliferative disease (LPD) after an unrelated cord blood transplantation, serum EBV-DNA progressively increased to 4 x 10(5) copies/mL. EBV load was then prospectively monitored in peripheral blood from posttransplantation patients. The second case was an 8 year-old boy with aplastic anemia who received a CD34+ cell transplantation. This patient died of LPD with the progression of pulmonary nodules. EBV-DNA increased to 4 x 10(4) copies/mL after the control of cytomegalovirus reactivation. On the other hand, EBV-DNA was undetectable (<200 copies/mL) in the series of all 58 samples from 10 patients who did not develop LPD after hematopoietic stem cell transplantation. Sequential monitoring of circulating EBV-DNA by quantitative PCR may be a useful indicator for predicting the development of posttransplantation LPD.

Immunohistochemical study of apoptosis of lens epithelial cells in human and diabetic rat cataracts.

PURPOSE: To evaluate apoptosis of lens epithelial cells by immunohistochemical methods. METHODS: We performed terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assays on capsulotomy specimens (53 patients, 68 eyes) from patients who had undergone cataract surgery, and on the epithelium of diabetic cataracts in rats (72 rats, 144 eyes). An animal model of diabetic cataracts was prepared by injection of streptozotocin in 3-week-old rats. The specimens of rats were also examined using the proliferating cell nuclear antigen (PCNA) immunohistochemical staining method. RESULTS: Although some TUNEL-positive cells were detected in capsulotomy specimens, we recognized little correlation between their distribution and the morphological classification of the cataracts. In the animal model of diabetic cataracts, TUNEL-positive cells were seen around the regions of accumulated epithelial cells. In the accumulated regions, PCNA-labeled cells undergoing DNA synthesis were also detected. CONCLUSIONS: These results suggest the possibility that apoptosis occurs in human lens epithelial cells. Apoptosis and proliferation of lens epithelial cells may be induced by factors such as hyperglycemia.