Prevalence of Epilepsy among Cataract Patients

Associations between use of mood stabilizers and risk of cataract: A population-based nested case-control study

BACKGROUND

The aim of this study was to investigate whether use of mood stabilizers (MS) is associated with an increased risk of cataract development.

METHODS

We conducted a nested case-control study using National Health Insurance Research Database in Taiwan. A total of 14,288 patients with bipolar disorder (BD) and schizophrenia were included; 7651 in the cataract group and 6637 in the control group. Based on overall cumulative period of MS (lithium, carbamazepine, valproate, and lamotrigine) treatment, we categorized into following groups: no use, and duration < 1 year, 1 to 2 years, and > 2 years. Conditional logistic regression analysis was used to explore the association between use of MS and risk of cataract development.

RESULTS

The risks for cataract development were significantly higher in patients using lithium alone and lithium combined with other MS for more than 2 years (adjusted odd ratio [AOR] = 1.39; 95% CI = 1.01-1.92, p = 0.043 and AOR = 1.44; 95% CI = 1.13-1.85, p = 0.003, respectively) than in non-users. Furthermore, the risks of cataract development increased in those treated with valproic acid combined with other MS (AOR = 1.26; 95% CI = 1.02-1.57, p = 0.035). Finally, no increased risks of cataract development were found in carbamazepine and lamotrigine users.

CONCLUSIONS

We found increased risks of cataract development in long-term users of lithium, lithium combined with other MS and valproic acid combined with other MS for more than two years among patients with BD and schizophrenia.

The Role of DNA Methylation in Lens Development and Cataract Formation

Epigenetics pertains to heritable alterations in genomic structural modifications without altering genomic DNA sequence. The studies of epigenetic mechanisms include DNA methylation, histone modifications, and microRNAs. DNA methylation may contribute to silencing gene expression which is a major mechanism of epigenetic gene regulation. DNA methylation regulatory mechanisms in lens development and pathogenesis of cataract represent exciting areas of research that have opened new avenues for association with aging and environment. This review addresses our current understanding of the major mechanisms and function of DNA methylation in lens development, age-related cataract, secondary cataract, and complicated cataract. By understanding the role of DNA methylation in the lens disease and development, it is expected to open up a new therapeutic approach to clinical treatment of cataract.

Association between antipsychotic drug use and cataracts in patients with bipolar disorder: A population-based, nested case-control study

BACKGROUND

No previous study has focused on the association between use of antipsychotic drugs and the development of cataracts in patients with bipolar disorder (BD); hence, we aimed to examine this association in the present study.

METHODS

We conducted a retrospective nested case-control study using data from the National Health Insurance Database of Taiwan between 2000 and 2011. A total of 3292 BD patients, 1684 with cataracts and 1608 controls matched for age, sex, and index date, were included. Antipsychotic drug exposure was categorized by type of drug and duration of use. A conditional logistic regression analysis was used to analyze the association.

RESULTS

Among BD patients, we found significantly reduced odds ratio (OR) of cataract development among past (adjusted OR (AOR), 0.74; 95% confidence interval (CI), 0.62-0.89; p=0.001) and continuous users (AOR, 0.71; 95% CI, 0.59-0.85; p<0.001) of atypical antipsychotics. No association was found between the odds of cataract development and typical antipsychotics. Besides, concomitant use of antidepressants (AOR, 1.23; 95% CI, 1.06-1.43; p=0.007) and mood stabilizers (AOR, 1.23; 95% CI, 1.06-1.42; p=0.007) were associated with increased odds of cataract development.

LIMITATIONS

Some important contributors to cataract development such as family history of cataract, smoking and alcohol exposure could not be measured from the claims data and this may confound the results.

CONCLUSIONS

Reduced odds of cataract were found in patients with BD taking atypical antipsychotics. However, given that BD patients often have risk factors for developing cataract, regular ocular evaluations are recommended for those treated with antipsychotics drugs.

Cataract and glaucoma development in juvenile neuronal ceroid lipofuscinosis (batten disease)

BACKGROUND

Ophthalmologic studies of Juvenile Neuronal Ceroid Lipofuscinosis (JNCL) have focused mainly on retinal involvement, and so far no anterior segment abnormalities have been described. In the present study, we report the findings of pre-senile cataract in five patients with JNCL.

MATERIAL AND METHODS

Our sample consisted of 35 patients (19 males, 16 females) with JNCL associated to the Centre for Rare Disease, Aarhus University Hospital. They represent all patients with JNCL born in Denmark in the period 1971-2003. At the half-yearly routine outpatient visits, the anterior section was examined by ordinary penlight without instillation of a mydriatic, and if abnormalities such as cataracts were detected or suspected, the patients were referred for an ophthalmologic examination including slit lamp examination. Follow up was obtained on all patients referred for ophthalmologic examination.

RESULTS

During the study period (1996-2012), five patients were identified with cataract. The patients' average age at detection of cataract was 20.1 + 1.6 years (mean + 2SD). Two of the five patients developed acute glaucoma, and in one case prophylactic cataract surgery was performed.

CONCLUSIONS

Cataract formation and a secondary acute glaucoma are complications in JNCL which do occur. We recommend that a complete ophthalmological examination of the anterior segment should be performed routinely in patients with JNCL beyond the age of 16 years of age in order to prevent a painful and harmful acute glaucoma which may occur due to mature cataract formation.

Valproic acid suppresses Nrf2/Keap1 dependent antioxidant protection through induction of endoplasmic reticulum stress and Keap1 promoter DNA demethylation in human lens epithelial cells

Recent epidemiological studies confirm the prevalence of cataract in epileptic patients. Similarly, the drugs used to treat epilepsy also show the connection with increased cataract formation. In this present study, we investigated the suppression of Nrf2/Keap1 dependent antioxidant protection through induction of endoplasmic (ER) stress and Keap1 promoter DNA demethylation in human lens epithelial cells (HLECs) treated with valproic acid (VPA), an antiepileptic drug. 20 mM VPA induces ER stress and activates the unfolded protein response (UPR) within 4 h by activating the ER stress sensor proteins, such as PERK, IRE1α, and ATF6 in HLECs. Consequently, the integrated ER stress signals, such as eIF2α, ATF4, BiP, and CHOP are altered accordingly to induce ER-Ca2+ release, reactive oxygen species (ROS) overproduction, and cell death in HLECs treated with VPA. VPA also suppresses the Nrf2, catalase, and glutathione reductase expressions with significant increases in Keap1 protein. Bisulphite genomic DNA sequencing reveals the promoter DNA demethylation in the Keap1 promoter, which results in the overexpression of Keap1 mRNA and protein in HLECs treated with 20 mM VPA. VPA also alters the expression profiles of passive DNA demethylation pathway enzymes such Dnmt1, Dnmt3a, Dnmt3b, and active DNA demethylation pathway enzyme, TET1 leading to DNA demethylation in the Keap1 promoter of HLECs. Overexpressed Keap1 decreases the Nrf2 level, thereby abolishing the Nrf2 dependent antioxidant protection. This might be responsible for lenticular proteins oxidation and cataract formation.

GluA2 AMPA glutamate receptor subunit exhibits codon 607 Q/R RNA editing in the lens

Regulated GluA2 AMPA receptor subunit expression, RNA editing, and membrane localization are fundamental determinants of neuronal Ca(2+) influx, and underlie basic functions such as memory and the primary brain disorder epilepsy. Consistent with this, AMPARs, and specifically GluA2, are targets of common antiepileptic drugs (AEDs) and antidepressants. Recently, epidemiological associations between epilepsy and increased cataract prevalence were found comparable to cataract links with diabetes and smoking. Similarly, use of AEDs and several antidepressants also showed links with increased cataract. Here, we demonstrated GluA2 in lenses, consistent with REST/NRSF and REST4 we described previously in lenses, as well as GluA1 and ADAR2 in the lens. Surprisingly, we found predominant neuron-like Q/R editing of GluA2 RNAs also occurs in the lens and evidence of lens GluA2 phosphorylation and STEP phosphatases linked with GluA2 membrane localization in neurons. This study is among the first to show GluA2 expression and predominant Q/R RNA editing in a non-neural cell. Our results suggest GluA2 AMPARs have related roles in lens physiology and disease processes, and provide evidence these anticonvulsant and antidepressant drug targets also occur in the lens.