Serum antioxidative enzymes levels and oxidative stress products in age-related cataract patients

Effects and potential mechanisms of exercise and physical activity on eye health and ocular diseases

In the field of eye health, the profound impact of exercise and physical activity on various ocular diseases has become a focal point of attention. This review summarizes and elucidates the positive effects of exercise and physical activities on common ocular diseases, including dry eye disease (DED), cataracts, myopia, glaucoma, diabetic retinopathy (DR), and age-related macular degeneration (AMD). It also catalogues and offers exercise recommendations based on the varying impacts that different types and intensities of physical activities may have on specific eye conditions. Beyond correlations, this review also compiles potential mechanisms through which exercise and physical activity beneficially affect eye health. From mitigating ocular oxidative stress and inflammatory responses, reducing intraocular pressure, enhancing mitochondrial function, to promoting ocular blood circulation and the release of protective factors, the complex biological effects triggered by exercise and physical activities reveal their substantial potential in preventing and even assisting in the treatment of ocular diseases. This review aims not only to foster awareness and appreciation for how exercise and physical activity can improve eye health but also to serve as a catalyst for further exploration into the specific mechanisms and key targets through which exercise impacts ocular health. Such inquiries are crucial for advancing innovative strategies for the treatment of eye diseases, thereby holding significant implications for the development of new therapeutic approaches.

Lens Cytoskeleton: An Update on the Etiopathogenesis of Human Cataracts

A cataract is a loss of the transparency of a normal crystalline lens. Multiple factors, including age as the major risk factor for cataracts, can disturb the transparency of the crystalline lens due to cumulative damage from environmental insults to proteins, particularly crystallins. Lens proteins do not turnover, and crystallins undergo extensive post-translational modifications (PTMs) with age in order to interact with each other and maintain their soluble basis for lens transparency. These PTMs include truncation, oxidation, deamidation, acetylation, phosphorylation, and glycosylation. Cataract formation, apart from protein PTMs, involves protein crosslinking, protein insolubilization, and aggregation. Oxidation is a key feature in age-related cataract formation. Due to the role of genetic and environmental factors, as well as its variable clinical presentation, we consider cataracts to be a multifactorial disease. The preliminary results of our study indicate that proteins implicated in the pathway of a structural constituent of the eye lens (BFSP1, BFSP2, CRYAA, CRYAB, CRYBA, CRYBB, CRYGC, CRYGD, CRYGS, KRTs, and VIM), together with AQP1 and AQP5, may also be involved in lens aging.

Investigation of the potential roles of adipose stem cells and substances of natural origin in the healing process of E. coli infected wound model in Rats

Skin infections by pathogenic microorganisms are a serious problem due to the potential of dissemination through the bloodstream to various organs causing toxic effects that may be up to mortality. Escherichia coli (E. coli) is one of the most predominant Gram-negative bacterial species present globally with great attention for investigation. The current study is designed to investigate the possible role of adipose tissue-derived stem cells (ADSCs), as well as natural products such as Trichoderma viride (T. viride) extract, Saccharomyces boulardii (S. boulardii) solution in the enhancement of wound healing process in the infected skin with E. coli. Ninety-six female rats were divided into 8 groups (12 animal/group): normal skin, wounded skin, wounded skin infected with E. coli, infected-wounded skin treated by ADSCs, infected-wounded skin treated by T. viride extract, infected-wounded skin treated by S. boulardii solution, infected-wounded skin treated a combination of treatments, infected-wounded skin treated by gentamicin. At day 21 animal weights and bacterial count were detected and compared. Animals were sacrificed and skin from various groups was investigated using a light microscope for sections stained by (hematoxylin eosin, Masson trichrome, and PCNA) as well as transmission electron microscopy. Pro-inflammatory (IL-1β, TNF- α, and IL-13), anti-inflammatory cytokine (IL-4), and antioxidant enzymes (Superoxide dismutase, glutathione, and catalase) were assessed in various groups revealing that ADSCs lightly shift levels of these parameters in various rat groups to regular levels, while administration of T. viride extract, S. boulardii solution, their combination with ADSCs and gentamicin treatment drive the tested cytokines and enzymes to significant levels similar to a normal level where combination therapy gave the best result. The current findings revealed the possibility of using certain natural products as possible substitutes to regularly applied antibiotics with successive protective results in the wound infection model.

Investigation of the antioxidant effect of Chrysin in an experimental cataract model created in chick embryos

PURPOSE

Cataract, which occurs as a result of lens opacification, is one of the most common causes of vision loss. In the literature, deterioration of the antioxidant system due to the increase in reactive oxygen species and oxidant levels is shown among the causes of cataract formation. The aim of this study was to investigate the antioxidant effect of chrysin on steroid-induced cataract development in an experimental chick embryo model using morphological, histological and biochemical parameters.

METHODS

Within the scope of the study, 150 specific pathogen free (SPF) fertilized eggs were used. Eggs were divided into 6 groups as control (group 1), corn oil (group 2), hydrocortisone hemisuccinate sodium (HC) (group 3), low dose chrysin (group 4), medium dose chrysin (group 5) and high dose chrysin (group 6). On the 15th day of incubation, Chrysin and HC were applicated to the air sac of the eggs with Hamilton and/or insulin injector. On day 17, the chick embryos were removed from the eggs and the bulbus oculi of the embryos were dissected. Lenses of 9 embryos were used for morpholigical cataract grading in each group, lens of 8 embryos for biochemical analysis and intact eyes of 7 embryos for histological evaluation (TUNEL method).

RESULTS

No opacity was observed in any of the lenses in Group 1 and 2. Cataract was observed in all lenses in Group 3. The mean opacity grades in group 3 were statistically significantly higher when compared to group 1 and 2 (p<0.05). The difference between group 6 and group 3 was statistically significant (p<0.05). GSH and TAS levels in the lenses were statistically significantly decreased compared to the control group due to HC application (p<0.05). It was determined that the decreased GSH and TAS levels in the lenses increased in relation to the Chrysin application doses. The increased levels of MDA, TOS, caspase 3 and caspase 9 in the HC group decreased significantly depending to the chrysin doses (p<0.05). In addition, while the rate of apoptotic cells determined by the TUNEL method was statistically significantly higher in the HC administered group than in the control group (p<0.05), it was statistically significantly decreased in the chrysin-administered groups, in relation to the dose of chrysin (p<0.05).

CONCLUSIONS

We think that anti-cataract effect of crhysin may be due to the antioxidant and antiapoptotic properties of chrysin. However, more research is needed to clarify the anti-cataract effects of chrysin.

Neuroprotective effects of a combination of Boswellia papyrifera and Syzygium aromaticum on AlCl3 induced Alzheimer's disease in male albino rat

Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by hippocampal, and cortical neuron deterioration, oxidative stress, and severe cognitive dysfunction. Aluminum is a neurotoxin inducer for cognitive impairments associated with AD. The treatment approaches for AD are unsatisfactory. Boswellia papyrifera and Syzygium aromaticum are known for their pharmacological assets, including antioxidant activity. Therefore, the current study explored the possible mitigating effects of a combination of Boswellia papyrifera and Syzygium aromaticum against aluminum chloride (AlCl3) induced AD. The AD model was established using AlCl3 (100 mg/kg), and the rats were orally administrated with Boswellia papyrifera or Syzygium aromaticum or a combination of them daily for 8 weeks. The Y-maze test was used to test cognition in the rats, while acetylcholinesterase (AChE) and oxidative stress markers were estimated in homogenates of the cerebral cortex and hippocampus. Also, the histopathological examination of the cortex and hippocampus were investigated. The results revealed that administration of either B. papyrifera or S. aromaticum extracts significantly improved the cognitive functions of AD rats, enhanced AChE levels, increased oxidative enzymes levels, including SOD and GSH, and reduced MDA levels in homogenates of the cerebral cortex and hippocampus and confirmed by improvement in histological examination. However, using a combination therapy gave better results compared to a single treatment. In conclusion, the present study provided primary evidence for using a combination of B. papyrifera and S. aromaticum to treat cognitive dysfunction associated with AlCl3 Induced AD by improving the AChE levels and modulating oxidative stress in the brain.

Is Cataract in Patients under 60 Years Associated with Oxidative Stress?

Oxidative stress is considered as a possible factor in the genesis of cataract. The study aimed to determine the systemic antioxidant status in cataract patients under 60 years. We studied 28 consecutive cataract patients, mean of 53 years (SD = 9.2), a range of 22-60 and 37 controls. In erythrocytes, activity of antioxidant enzymes was determined: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in contrast with plasma concentrations of vitamin A and E. Conjugated dienes (CD) level and protein carbonyls (PC) concentration were also determined in plasma. Malondialdehyde (MDA) concentrations in erythrocytes and plasma were also measured. SOD and GPx activity and vitamin A and E concentrations were lower in cataract patients (p = 0.000511, 0.02, 0.022, and 0.000006, respectively). MDA plasma and erythrocytes concentrations were higher in cataract patients (p = 0.000001 and 0.0000001, respectively). PC concentration was higher in cataract patients than in controls (p = 0.00000013). There were statistically significant correlations between oxidative stress markers both in the cataract patients group as well as in the control group. Cataract incidence in patients under 60 years seems to be accompanied by enhanced lipid peroxidation and protein oxidation, as well as antioxidant defense depletion. Thus, supplementation with antioxidants could be beneficial in this group of patients.

m6A Modification-Association with Oxidative Stress and Implications on Eye Diseases

Oxidative stress (OS) refers to a state of imbalance between oxidation and antioxidation. OS is considered to be an important factor leading to aging and a range of diseases. The eyes are highly oxygen-consuming organs. Due to its continuous exposure to ultraviolet light, the eye is particularly vulnerable to the impact of OS, leading to eye diseases such as corneal disease, cataracts, glaucoma, etc. The N6-methyladenosine (m6A) modification is the most investigated RNA post-transcriptional modification and participates in a variety of cellular biological processes. In this study, we review the role of m6A modification in oxidative stress-induced eye diseases and some therapeutic methods to provide a relatively overall understanding of m6A modification in oxidative stress-related eye diseases.

Linear association between aging and decreased blood thiol antioxidant activity in patients with cataract

We comprehensively assessed the roles of systemic redox markers by including both prooxidant and antioxidant markers in 121 Japanese subjects (mean ± SD age, 70 ± 11 years; 38 men) with no ocular pathology except age-related cataract. Serum levels of lipid peroxides, ferric-reducing activity, and thiol antioxidant activity were measured using the diacron reactive oxygen metabolite (dROM), biologic antioxidant potential (BAP), and sulfhydryl (SH) tests, respectively, using a free-radical analyzer. Univariate analyses suggested that older age, higher pulse rate, worse best-corrected visual acuity (BCVA), higher intraocular pressure, and higher cataract grade were associated with a lower SH level. Scatterplots revealed virtually linear associations between age and the SH level (estimate, -4.4 μM/year). Multivariate analyses suggested that older age, higher systolic blood pressure, and worse BCVA were associated with a lower SH level. Neither the univariate nor multivariate analyses, except between female sex and higher dROM level, were associated with the dROM or BAP level. A lower serum SH level was the driver of aging itself and age-related decline in VA due to cataract. The serum SH level may be an excellent predictor of aging status in each subject.

Evaluation of antioxidative enzymes levels and lipid peroxidation products levels in diabetic and non diabetic senile cataract patients

Background

The current study aimed to investigate the Superoxide dismutase, Glutathione Peroxidase activity, Advanced oxidation Protein products levels, Malondialdehyde levels, Baseline Conjugated Diene concentration, and 8-Isoprostaglandin F2α (8-IPG-F2α) quantification in diabetic and non-diabetic senile cataract patients to find out the pathomechanism of early onset of cataract in diabetic patients.

Methods

This case-control study was performed on 184 subjects undergoing cataract surgery. For 8-IPG-F2α quantification, 35 diabetics and non-diabetic lenses and the entire study included 22 patients with diabetic senile cataracts and non-diabetic senile cataracts of aqueous humor age ≥ 40 years. Ninety-two patients with diabetic senile cataract and non-diabetic senile cataract lenses aged ≥ 40 years were incorporated for all other studies. The student's t-test was used for statistical analysis.

Results

From the study population, the mean age was 63.82 ± 0.6, and 75% of them were female. Higher female prevalence in both groups was observed. The results revealed that the superoxide dismutase and glutathione peroxidase activity were significantly reduced in diabetic patients compared to non-diabetic patients (p < 0.001) in both lenses and aqueous humor. Malondialdehyde, conjugated diene, and 8-IPG-F2α levels significantly increased in diabetic patients when compared to non-diabetic (p < 0.01), and advanced oxidation protein products levels also significantly increased in diabetic patients when compared to non-diabetics in both lenses and aqueous humor (p < 0.001).

Conclusion

The current study revealed that oxidative stress and Lipid per-oxidation have an imperative role in the diabetic-related complication, specifically in the lens, may have a responsibility in the pathomechanism of early onset of cataracts coupled with diabetes mellitus.

Senescence marker protein30 protects lens epithelial cells against oxidative damage by restoring mitochondrial function

Etiology and pathogenesis of age-related cataract is not entirely clear till now. Senescence marker protein 30 (SMP30) is a newly discovered anti-aging factor, which plays an important role in preventing apoptosis and reducing oxidative stress damage. Mitochondria are located at the intersection of key cellular pathways, such as energy substrate metabolism, reactive oxygen species (ROS) production and apoptosis. Oxidative stress induced by 4-hydroxynonenal (4-HNE) is closely related to neurodegenerative diseases and aging. Our study focused on the effect of SMP30 on mitochondrial homeostasis of human lens epithelial cells (HLECs) induced by 4-HNE. Western blots and qPCR were used to compare the expression of SMP30 protein in the residual lens epithelial cells in the lens capsule of age-related cataract (ARC) patients and the donated transparent lens capsule. On this basis, SMP30 overexpression plasmid and SMP30 shRNA interference plasmid were introduced to explore the effect of SMP30 on the biological behavior in HLECs under the condition of oxidative stress induced by 4-HNE through immunohistochemistry, ROS evaluation, metabolic spectrum analysis and JC-1 fluorescence measurement. Given that Nuclear Factor erythroid 2-Related Factor 2 (Nrf2)/Kelch Like ECH Associated Protein 1 (KEAP1) signaling pathway is the most important antioxidant stress pathway, we further analyzed the regulatory effect of SMP30 by WB to explore its molecular mechanism. Our study indicated that SMP30 may inhibit ROS accumulation, restore mitochondrial function, activate Nrf2/Keap1 signaling pathway, therefore protecting lens epithelial cells from oxidative stress-induced cell damage.

High MST2 expression regulates lens epithelial cell apoptosis in age-related cataracts through YAP1 targeting GLUT1

Age-related cataract (ARC) is a severe visual impairment disease and its pathogenesis remains unclear. This study investigated the relevance of MST2/YAP1/GLUT1 in ARC development in vivo and in vitro, and explored the role and possible mechanisms of this pathway in oxidative damage-mediated apoptosis of lens epithelial cells (LECs). Western blot analysis and immunohistochemistry showed that MST2 and phosphorylated (p)-YAP (Ser127) protein levels were increased, and YAP1 and GLUT1 protein levels were decreased in LECs of ARC patients and aged mice. Additionally, differential expression of MST2 and YAP1 was associated with H₂O₂-induced apoptosis of human lens epithelial B3 (HLE-B3) cells. CCK-8 and Hoechst 33,342 apoptosis assays showed that MST2 and YAP1 were involved in H₂O₂-induced apoptosis of LECs. Subsequent experiments showed that, during MST2-mediated H₂O₂-induced apoptosis, p-YAP (Ser127) levels were elevated and immunofluorescence revealed nucleoplasmic translocation and inhibition of YAP1 protein expression. Furthermore, GLUT1 was in turn synergistically transcriptionally regulated by YAP1-TEAD1 in dual luciferase reporter assays. In conclusion, our study indicates that the MST2/YAP1/GLUT1 pathway plays a major role in the pathogenesis of ARC and LECs apoptosis, providing a new direction for future development of targeted inhibitors that block this signaling pathway to prevent, delay, or even cure ARC.

Effects of hormone replacement therapy on lens opacity, serum inflammatory cytokines, and antioxidant levels

PURPOSE

To evaluate the effect of hormone replacement therapy (HRT) on lens opacity as measured by Scheimpflug densitometry, serum inflammatory cytokines, and antioxidant levels.

METHODS

A total of 264 women who were at least five years beyond menopause were included. The control group of 128 patients (Group 1) did not use HRT at any time after menopause. The treatment group of 136 patients (Group 2) used HRT for5 years or more after menopause. Cortical, nuclear, and posterior subcapsular density; pentacam nucleus staging (PNS); pentacam densitometry of zone (PDZ) as measured using a Scheimpflug imaging system (Pentacam); and antioxidant and inflammatory cytokines activities in serum using multiplex bead analysiswere examined.

RESULTS

Uncorrected visual acuity (logMAR) of group1 was significantly worse than those of group 2 (p < .05). Group1 was significantly more myopic than group 2 (p < .05). Nuclear and posterior subcapsular density, PNS, and percentage of PDZ in group 1 were significantly higher than those of group 2 (p < .05). The serum IL-1m. IL-6, IL-8, and TGF-, concentrations of group 1 were significantly higher than those of group 2, and the serum catalase, superoxide dismutase 1 (SOD 1), and superoxide dismutase 2 (SOD 2) fluorescence intensities of group 1 were significantly lower than those of group 2 (p < .05).

CONCLUSIONS

Long-term use of HRT may have a protective effect against cataract formation. HRT seems to be effective in decreasing inflammation and increasing antioxidant contents in the serum of postmenopausal women.KEY MESSAGESHormone replacement therapy (HRT) decrease lens opacity in postmenopausal women as measured by Scheimpflug densitometry.HRT decrease serum inflammatory cytokines and increase antioxidant levelsin the serum of postmenopausal women.Long-term use of HRT may have a protective effect against cataract formationin postmenopausal women.

Hallmarks of lens aging and cataractogenesis

Lens homeostasis and transparency are dependent on the function and intercellular communication of its epithelia. While the lens epithelium is uniquely equipped with functional repair systems to withstand reactive oxygen species (ROS)-mediated oxidative insult, ROS are not necessarily detrimental to lens cells. Lens aging, and the onset of pathogenesis leading to cataract share an underlying theme; a progressive breakdown of oxidative stress repair systems driving a pro-oxidant shift in the intracellular environment, with cumulative ROS-induced damage to lens cell biomolecules leading to cellular dysfunction and pathology. Here we provide an overview of our current understanding of the sources and essential functions of lens ROS, antioxidative defenses, and changes in the major regulatory systems that serve to maintain the finely tuned balance of oxidative signaling vs. oxidative stress in lens cells. Age-related breakdown of these redox homeostasis systems in the lens leads to the onset of cataractogenesis. We propose eight candidate hallmarks that represent common denominators of aging and cataractogenesis in the mammalian lens: oxidative stress, altered cell signaling, loss of proteostasis, mitochondrial dysfunction, dysregulated ion homeostasis, cell senescence, genomic instability and intrinsic apoptotic cell death.

Metformin alleviates oxidative stress-induced senescence of human lens epithelial cells via AMPK activation and autophagic flux restoration

Cataracts are the leading cause of blindness worldwide owing to the increasing proportion of elderly individuals in the population. The purpose of this study was to investigate whether metformin could alleviate the occurrence and development of age‐related cataract (ARC) and the underlying mechanism. In the present study, we established a senescence model induced by oxidative stress, which was confirmed by measuring β‐galactosidase activity, qRT‐PCR and Western blotting. In addition, we showed that metformin alleviated the oxidative stress‐induced senescence of HLE‐B3 cells via the activation of AMPK. Next, we provided evidence that oxidative stress impaired autophagic flux and induced lysosomal dysfunction. Subsequently, we found that metformin restored autophagic flux that had been impaired by oxidative stress by activating AMPK. Additionally, we found that metformin suppressed HLE‐B3 cell senescence by improving lysosomal function and inactivating mTOR. Furthermore, the inactivation of AMPK, impairment of autophagic flux and lysosomal dysfunction were observed in the human lens epithelium of ARC. In summary, our data suggest that the activation of AMPK may be a potential strategy for preventing ARC, and metformin may be an emerging candidate to alleviate the formation and development of ARC.

Superoxide Dismutase Administration: A Review of Proposed Human Uses

Superoxide dismutases (SODs) are metalloenzymes that play a major role in antioxidant defense against oxidative stress in the body. SOD supplementation may therefore trigger the endogenous antioxidant machinery for the neutralization of free-radical excess and be used in a variety of pathological settings. This paper aimed to provide an extensive review of the possible uses of SODs in a range of pathological settings, as well as describe the current pitfalls and the delivery strategies that are in development to solve bioavailability issues. We carried out a PubMed query, using the keywords "SOD", "SOD mimetics", "SOD supplementation", which included papers published in the English language, between 2012 and 2020, on the potential therapeutic applications of SODs, including detoxification strategies. As highlighted in this paper, it can be argued that the generic antioxidant effects of SODs are beneficial under all tested conditions, from ocular and cardiovascular diseases to neurodegenerative disorders and metabolic diseases, including diabetes and its complications and obesity. However, it must be underlined that clinical evidence for its efficacy is limited and consequently, this efficacy is currently far from being demonstrated.

Profiling and Integrated Analysis of the ERCC6-regulated circRNA-miRNA-mRNA Network in Lens Epithelial Cells

Purpose: To explore the regulatory role of ERCC6 in the circRNA-miRNA-mRNA network using a cellular ERCC6 overexpression model (OE-ERCC6) in lens epithelial cells.Methods: The expression profiles of circRNAs, miRNAs and mRNAs were determined by RNA-seq, and a regulatory circRNA-miRNA-mRNA network was constructed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used for the functional annotation of circRNA host genes, differentially expressed (DE) genes, and miRNA targets.Results: The DE molecules between the OE-ERCC6 and control groups included 269 circRNAs, 241 miRNAs and 3500 mRNAs. We validated 5 selected DE reads of circRNAs (hsa_circ_0001009, hsa_circ_0002024, hsa_circ_0004592, hsa_circ_0001900 and hsa_circ_0001017). Subsequent bioinformatics analysis revealed that the DE circRNAs are mainly involved in oxidative stress- and cell death-related signaling pathways. Finally, a circRNA-miRNA-mRNA network focusing on DNA damage and cell death, which involved 5 circRNAs, 13 miRNAs and 107 mRNAs, was constructed.Conclusion: We constructed a circRNA-miRNA-mRNA network that is regulated by ERCC6. DE circRNAs have the potential to become therapeutic targets related to the lens lesions observed in ARC. The establishment of related in vivo and in vitro models could be a future direction to confirm these hypotheses.

Lactobacillus salivarius, a Potential Probiotic to Improve the Health of LPS-Challenged Piglet Intestine by Alleviating Inflammation as Well as Oxidative Stress in a Dose-Dependent Manner During Weaning Transition

Intestinal health is a critical issue for piglets during their weaning transition period. Previous reports have emphasized the promise of distinct probiotics in improving the enteric health. Here in this research, a newly isolated Lactobacillus salivarius strain was pretreated to Lipopolysaccharide (LPS)-challenged piglets and its association with integrity of the intestinal barrier coupled with effective dosage were expected to be signified. In the present study, 72 piglets (Landrace × Yorkshiere × Duroc) were randomly allotted to four groups, each group with six replicates. The subjects in the control group were provided with basal diet while those in other tested groups with extra 0.05, 0.1, and 0.2% L. salivarius, respectively. Fourteen days later, LPS was intraperitoneally injected and sodium pentobarbital was then delivered to euthanize those LPS-challenged piglets. An increase of average daily gain and body weight along with an apparent decline of diarrhea rate were observed in L. salivarius-treated groups. Both 0.1 and 0.2% L. salivarius supplement in total diet had the capability to markedly elevate levels of CAT, GSH-Px, SOD, anti-inflammatory cytokine from the serum as well as tight junction proteins (Claudin-1, Occludin, and ZO-1) extracted from intestine in LPS-challenged piglets. These changes were accompanied by the obvious downregulation of D-lactic acid, DAO, MDA and pro-inflammatory mediators in the serum, including IL-1β, IL-6, IFN-γ, and TNF-α. Meanwhile, the expression levels of TLR2 and TLR4 in spleen and mesenteric lymph nodes were significantly lower whereas the oxidation-related gene, ho-1 was up-regulated with L. salivarius administration. Our findings suggested that relatively high dose L. salivarius (0.1–0.2%) could regulate the progression of inflammatory response and oxidative stress when individuals were exposed to LPS, thus probably offering valuable assistance in restoring barrier function and improving overall performance.

Glycation-mediated protein crosslinking and stiffening in mouse lenses are inhibited by carboxitin in vitro

Proteins in the eye lens have negligible turnover and therefore progressively accumulate chemical modifications during aging. Carbonyls and oxidative stresses, which are intricately linked to one another, predominantly drive such modifications. Oxidative stress leads to the loss of glutathione (GSH) and ascorbate degradation; this in turn leads to the formation of highly reactive dicarbonyl compounds that react with proteins to form advanced glycation end products (AGEs). The formation of AGEs leads to the crosslinking and aggregation of proteins contributing to lens aging and cataract formation. To inhibit AGE formation, we developed a disulfide compound linking GSH diester and mercaptoethylguanidine, and we named it carboxitin. Bovine lens organ cultured with carboxitin showed higher levels of GSH and mercaptoethylguanidine in the lens nucleus. Carboxitin inhibited erythrulose-mediated mouse lens protein crosslinking, AGE formation and the formation of 3-deoxythreosone, a major ascorbate-derived AGE precursor in the human lens. Carboxitin inhibited the glycation-mediated increase in stiffness in organ-cultured mouse lenses measured using compressive mechanical strain. Delivery of carboxitin into the lens increases GSH levels, traps dicarbonyl compounds and inhibits AGE formation. These properties of carboxitin could be exploited to develop a therapy against the formation of AGEs and the increase in stiffness that causes presbyopia in aging lenses.

A Mechanistic Review of β-Carotene, Lutein, and Zeaxanthin in Eye Health and Disease

Carotenoids are natural lipid-soluble antioxidants abundantly found as colorful pigments in fruits and vegetables. At least 600 carotenoids occur naturally, although about 20 of them, including β-carotene, α-carotene, lycopene, lutein, zeaxanthin, meso-zeaxanthin, and cryptoxanthin, are detectable in the human blood. They have distinct physiological and pathophysiological functions ranging from fetal development to adult homeostasis. β-carotene is a precursor of vitamin A that essentially functions in many biological processes including vision. The human macula lutea and eye lens are rich in lutein, zeaxanthin, and meso-zeaxanthin, collectively known as macular xanthophylls, which help maintain eye health and prevent ophthalmic diseases. Ocular carotenoids absorb light from the visible region (400-500 nm wavelength), enabling them to protect the retina and lens from potential photochemical damage induced by light exposure. These natural antioxidants also aid in quenching free radicals produced by complex physiological reactions and, consequently, protect the eye from oxidative stress, apoptosis, mitochondrial dysfunction, and inflammation. This review discusses the protective mechanisms of macular xanthophylls in preventing eye diseases such as cataract, age-related macular degeneration, and diabetic retinopathy. Moreover, some preclinical animal studies and some clinical trials are discussed briefly to understand carotenoid safety and efficacy.

4-Hydroxynonenal induces Cx46 hemichannel inhibition through its carbonylation

Hemichannels formed by connexins mediate the exchange of ions and signaling molecules between the cytoplasm and the extracellular milieu. Under physiological conditions hemichannels have a low open probability, but in certain pathologies their open probability increases, which can result in cell damage. Pathological conditions are characterized by the production of a number of proinflammatory molecules, including 4-hydroxynonenal (4-HNE), one of the most common lipid peroxides produced in response to inflammation and oxidative stress. The aim of this work was to evaluate whether 4-HNE modulates the activity of Cx46 hemichannels. We found that 4-HNE (100 μM) reduced the rate of 4',6-diamino-2-fenilindol (DAPI) uptake through hemichannels formed by recombinant human Cx46 fused to green fluorescent protein, an inhibition that was reversed partially by 10 mM dithiothreitol. Immunoblot analysis showed that the recombinant Cx46 expressed in HeLa cells becomes carbonylated after exposure to 4-HNE, and that 10 mM dithiothreitol reduced its carbonylation. We also found that Cx46 was carbonylated by 4-HNE in the lens of a selenite-induced cataract animal model. The exposure to 100 μM 4-HNE decreased hemichannel currents formed by recombinant rat Cx46 in Xenopus laevis oocytes. This inhibition also occurred in a mutant expressing only the extracellular loop cysteines, suggesting that other Cys are not responsible for the hemichannel inhibition by carbonylation. This work demonstrates for the first time that Cx46 is post-translationally modified by a lipid peroxide and that this modification reduces Cx46 hemichannel activity.

MDM2 phosphorylation mediates H2O2-induced lens epithelial cells apoptosis and age-related cataract

Lens epithelial cells (LECs) apoptosis induced by oxidative stress is a major factor in age-related-cataract (ARC) pathogenesis, but there are still many blind nodes in this progress. This study aimed to investigate the effects of MDM2 phosphorylation in ARC and H₂O₂-induced lens epithelial cells apoptosis. Our results confirmed that the levels of p-MDM2 (Ser166) and p-MDM2 (Ser186) in the anterior lens capsules of human cataracts were reduced compared to that in normal capsules. Similarly, in naturally aging cataract mice, the level of MDM2 phosphorylation also decreased. Oxidative stress-induced apoptosis model was constructed by cultivating HLE-B3 cells with 200 μM H₂O₂. It was confirmed that MDM2 could regulate lens epithelial cell apoptosis, and MDM2 inhibitors could partly inhibited AKT's role in suppressing apoptosis induced by H₂O₂. Besides, we examed the decreased level of p-AKT(Ser473) in apoptosis of lens epithelial cells and ARC. Our study revealed that MDM2 phosphorylation mediated H₂O₂-induced lens epithelial cells apoptosis and ARC, which could provide new ideas for the clinical treatment of ARC.

L‑carnitine alleviates oxidative stress‑related damage via MAPK signaling in human lens epithelial cells exposed to H2O2

L‑carnitine (LC) is well known for its antioxidative properties. The present study aimed to evaluate the effects of LC on human lens epithelial cells (HLECs) and to analyze its regulatory mechanism in cataractogenesis. HLE B‑3 cells were cultured with hydrogen peroxide (H2O2) and were pretreated with or without LC. The Cell Counting kit‑8 assay was used to determine cell viability. Reactive oxygen species (ROS) assay kit was used to measure the cellular ROS production induced by H2O2 and LC. In addition, reverse transcription‑quantitative PCR and western blot analysis were performed to detect the expression levels of oxidative damage markers and antioxidant enzymes. Notably, ROS overproduction was observed upon exposure to H2O2, whereas LC supplementation markedly decreased ROS levels through activation of the antioxidant enzymes forkhead box O1, peroxiredoxin 4 and catalase. Furthermore, LC suppressed the expression of apoptosis‑associated genes (caspase-3) and inflammation‑associated genes [interleukin (IL)1, IL6, IL8 and cyclooxygenase‑2]. Conversely, LC promoted proliferating cell nuclear antigen, cyclin‑dependent kinase (CDK)2 and CDK4 expression, which may increase proliferation of HLECs that were incubated with H2O2. In addition, epithelial‑mesenchymal transition occurred upon ROS accumulation, whereas the effects of H2O2 on AQP1 and vimentin expression were reversed upon LC supplementation. Notably, this study revealed that LC restored the oxidant/antioxidant balance and protected against cell damage through the mitogen‑activated protein kinase signaling pathway. In conclusion, LC may serve a protective role in curbing oxidative damage and therefore may be considered a potential therapeutic agent for the treatment of cataracts.

Medicinal Plants and Natural Products Used in Cataract Management

Cataract is the leading reason of blindness worldwide and is defined by the presence of any lens opacities or loss of transparency. The most common symptoms of cataract are impaired vision, decreased contrast sensitivity, color disturbance, and glare. Oxidative stress is among the main mechanisms involved in the development of age-related cataract. Surgery through phacoemulsification and intraocular lens implantation is the most effective method for cataract treatment, however, there are chances of serious complications and irreversible loss of vision associated with the surgery. Natural compounds consisting of antioxidant or anti-inflammatory secondary metabolites can serve as potential leads for anticataract agents. In this review, we tried to document medicinal plants and plant-based natural products used for cataract treatment worldwide, which are gathered from available ethnopharmacological/ethnobotanical data. We have extensively explored a number of recognized databases like Scifinder, PubMed, Science Direct, Google Scholar, and Scopus by using keywords and phrases such as “cataract”, “blindness”, “traditional medicine”, “ethnopharmacology”, “ethnobotany”, “herbs”, “medicinal plants”, or other relevant terms, and summarized the plants/phytoconstituents that are evaluated in different models of cataract and also tabulated 44 plants that are traditionally used in cataract in various folklore medical practices. Moreover, we also categorized the plants according to scientific studies carried out in different cataract models with their mechanisms of action.

Antioxidant effects of piperine in in-vivo chick embryo cataract model induced by steroids

PURPOSE

The etiopathogenesis of steroid-induced cataracts is unknown. One hypothesis is that the higher reactive oxygen species (ROS) levels play an important role in the pathogenesis of several disorders, including the evolution of cataracts. This study investigated the antioxidant effects of piperine in our steroid-induced chick embryo lens model.

METHODS

The study included 36 specific pathogen-free (SPF) fertilized eggs divided into six groups: phosphate buffer saline (PBS, pH 7.4 Saline Solution (0.9%) isotonic) group (G1), hydrocortisone succinate sodium (HC)-treated group (G2), 100 mg/kg piperine and HC treated group (G3), 50 mg/kg piperine and HC treated group (G4), 25 mg/kg piperine and HC treated group (G5), and 10 mg/kg piperine and HC treated group (G6). On the 15th day of incubation, the SPF eggs in the six groups were removed from the incubator; all were injected using insulin injectors into the chorioallantoic membrane. On day 17, all of the chick embryos were removed from the eggs and all lenses were dissected from the embryos. Cataract formation was evaluated in all lenses, and total antioxidant status (TAS), total oxidant status (TOS), reduced glutathione (GSH), and lipid peroxidation (MDA, malondialdehyde) levels were measured in all lens.

RESULTS

The lenses in the G1 group had higher levels of GSH and TAS (p < 0.01), and lower levels of MDA and TOS than the G2 group (p < 0.05 and p < 0.01, respectively). Group 3 had higher levels of GSH and TAS (p < 0.001 and p < 0.001 respectively), and lower levels of MDA and TOS than the G2 group (p < 0.01 and p < 0.001, respectively).

CONCLUSION

Steroid therapy causes a decrease in GSH and TAS levels and an increase in TOS and MDA levels in lens tissues, indicating increased oxidative stress. Piperine exerts its effects as an antioxidant substance, in increasing doses.

Impact of moderate- and high-intensity exercise on the endothelial ultrastructure and function in mesenteric arteries from hypertensive rats

Oxidative stress (OS) influences vascular function and structure in spontaneously hypertensive rats (SHRs). It is also responsible for the decreased nitric oxide (NO) bioavailability that influences endothelial vasodilation. The effects of high-intensity exercise on endothelial function and ultrastructure in hypertension remain unknown. Thus, this study investigated the effects of moderate- and high-intensity exercise on hypertension-associated endothelial dysfunction and ultrastructural remodeling. Moderate-intensity (SHR-M) and high-intensity (SHRH) aerobic exercise training groups were compared in age-matched sedentary SHRs (SHRC) and normotensive Wistar-Kyoto rats (WKY-C). The results showed that the endothelial ultrastructure was impaired in the SHR-H and SHR-C groups. Glutathione peroxidase levels were significantly increased in the SHR-M group compared to the SHR-C group. MDA content was higher in the SHR-H group than in the SHR-C group, but the levels of antioxidant enzymes did not increase accordingly. Apocynin scavenging reactive oxygen species (ROS) ameliorated endothelium-dependent vasodilator function in the SHR-H group. However, the SHR-M and WKY-C groups abolished the increased vasodilation induced by apocynin. L-NAME, a NO synthase inhibitor, was applied to isolated mesenteric arteries (MAs) to evaluate NO contribution. Moderate-intensity exercise reversed the decreased NO contribution to MAs in hypertension, and high-intensity exercise aggravated this change. These data suggest that moderate-intensity exercise ameliorated adverse remodeling of the endothelial ultrastructure and function in hypertension by decreasing oxidative stress and increasing NO contribution. However, high-intensity exercise exacerbated all of these changes by increasing OS and ROS contribution, and decreasing NO contribution.

Inhibition of histone deacetylase protects the damaged cataract via regulating the NF-κB pathway in cultured lens epithelial cells

Induction of oxidative damage by the activation of histone deacetylase (HDAC) is an integral event that causes major membrane damage of ocular tissues and leads to the pathogenesis of cataract. It is elucidated that nuclear factor-κB is a mediator in the process of cataract development. However, studies on the role played by epigenetic proteins in regulating cataract pathogenesis are limited. Hence, in the current investigation, ARPE-19 human retinal epithelial cells were used as an experimental model to elucidate the role of HDAC inhibition and its mechanism behind the cataract pathogenesis. ARPE-19 cells were exposed to H2O2, with and without Trichostatin A (TSA), a pan-HDAC inhibitor, and maintained along with control cells without any treatment. On exposure to H2O2, cells were susceptible to oxidative stress as it is evident from the reduced expression levels of superoxide dismutase (SOD), catalase, and GSH levels. Simultaneously, H2O2-exposed cells showed the nuclear translocation of NF-κB with the activation of inflammatory cytokines such as CXCL1 and IL-6. In addition, the mRNA expression analysis revealed that the GADD45α, COX-2, MCP-1, and ICAM-1 expressions were increased in H2O2 group. Moreover, the activity of HDAC was increased to 2-fold with a significant reduction in the histone acetyltransferase (HAT) activity in cells that were maintained under oxidative conditions. However, TSA was able to inhibit the critical cytokines’ expression with attenuated HDAC activity and limited NF-κB translocation. Furthermore, pre-treatment of TSA significantly suppressed the transcript levels of up-regulated inflammatory markers in cells. Together, these findings offer new insight into the role of HDACs in regulating cellular processes involved in the pathogenesis of cataract as well as the potential use of HDAC inhibitors as therapeutics for controlling the disease progression.

UVB induces apoptosis via downregulation of CALML3-dependent JNK1/2 and ERK1/2 pathways in cataract

The aim of the current study was to understand the mechanisms of apoptosis occurring in cultured human lens epithelial cells (HLECs) following ultraviolet B (UVB) irradiation. The investigations intended to confirm the presence of apoptosis and to reveal the roles of oxidative stress, calcium (Ca2+), c‑Jun NH2‑terminal kinase (JNK)1/2, and extracellular signal‑regulated kinase (ERK)1/2 signaling pathway in these progresses. Cell apoptosis, ROS generation and intracellular Ca2+ concentration was measured by flow cytometry. The expression of CALML3, caspase-3, Bax, Bcl-2, p-JNK1/2, JNK1/2, p-ERK1/2 and ERK1/2 was measured by RT-qPCR and western blot analysis. Annexin V‑fluorescein isothiocyanate/propidium iodide staining demonstrated that UVB irradiation increased the apoptotic rate, reactive oxygen species (ROS) production and intracellular Ca2+ concentration of HLECs in dose‑ and time‑dependent manners. Overexpression of calmodulin like 3 (CALML3) reversed the effects of UVB irradiation on apoptosis, ROS production and Ca2+ concentration of HLECs, and decreased expressions of caspase‑3 and Bax, with increased expressions of Bcl‑2. Notably, silencing of CALML3 had similar effects to UVB irradiation and inhibited the activation JNK1/2 and ERK1/2 pathways. Nimodipine, a Ca2+‑channel antagonist, significantly attenuated the damages induced by CALML3 downregulation. In conclusion, UVB irradiation induced increase in apoptosis, ROS production and Ca2+ concentration of HLECs, in part, by downregulating the expression of CALML3 and involved oxidative stress, Ca2+, JNK1/2 and ERK1/2 signaling pathways, suggesting that investigating CALML3 may useful for developing cataract treatment.

Ghrelin Protects Human Lens Epithelial Cells against Oxidative Stress-Induced Damage

Oxidative stress has been recognized as an important mediator in the pathogenesis of age-related cataracts; using antioxidant supplements is one plausible strategy to protect the antioxidative defense system against oxidative stress. Ghrelin administration is expected to reduce ROS, preventing the onset of different diseases. The role of ghrelin, if any, in protecting against oxidative stress in HLECs has never been examined. In the present study, we investigated the effects of ghrelin against H₂O₂-induced oxidative stress and the associated molecular mechanisms in HLECs and rat lenses. The results showed that pretreatment with ghrelin reduced H₂O₂-induced cellular apoptosis and ROS accumulation, increased the expression levels of SOD and CAT, and decreased the expression level of MDA. The morphological examination showed that the ghrelin-treated lens organ culture maintained transparency. This is the first report to show that ghrelin can protect HLECs from H₂O₂-induced oxidative stress. Our findings suggest that ghrelin may prevent the progression of cataracts, which has treatment value for ophthalmologists.

Age-related cataracts: Role of unfolded protein response, Ca2+ mobilization, epigenetic DNA modifications, and loss of Nrf2/Keap1 dependent cytoprotection

Age-related cataracts are closely associated with lens chronological aging, oxidation, calcium imbalance, hydration and crystallin modifications. Accumulating evidence indicates that misfolded proteins are generated in the endoplasmic reticulum (ER) by most cataractogenic stresses. To eliminate misfolded proteins from cells before they can induce senescence, the cells activate a clean-up machinery called the ER stress/unfolded protein response (UPR). The UPR also activates the nuclear factor-erythroid-2-related factor 2 (Nrf2), a central transcriptional factor for cytoprotection against stress. Nrf2 activates nearly 600 cytoprotective target genes. However, if ER stress reaches critically high levels, the UPR activates destructive outputs to trigger programmed cell death. The UPR activates mobilization of ER-Ca2+ to the cytoplasm and results in activation of Ca2+-dependent proteases to cleave various enzymes and proteins which cause the loss of normal lens function. The UPR also enhances the overproduction of reactive oxygen species (ROS), which damage lens constituents and induce failure of the Nrf2 dependent cytoprotection. Kelch-like ECH-associated protein 1 (Keap1) is an oxygen sensor protein and regulates the levels of Nrf2 by the proteasomal degradation. A significant loss of DNA methylation in diabetic cataracts was found in the Keap1 promoter, which overexpresses the Keap1 protein. Overexpressed Keap1 significantly decreases the levels of Nrf2. Lower levels of Nrf2 induces loss of the redox balance toward to oxidative stress thereby leading to failure of lens cytoprotection. Here, this review summarizes the overall view of ER stress, increases in Ca2+ levels, protein cleavage, and loss of the well-established stress protection in somatic lens cells.

Associations of PARP-1 variant rs1136410 with PARP activities, oxidative DNA damage, and the risk of age-related cataract in a Chinese Han population: A two-stage case-control analysis

OBJECTIVE

To investigate whether a single nucleotide polymorphism (SNP) rs1136410 in the poly (ADP-ribose) polymerase-1 (PARP-1) gene was associated with PARP activities, 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, and the risk of age-related cataract (ARC) in a Chinese Han population.

METHODS

In this two-stage case-control study with a total of 1010 ARC patients and 1045 controls, SNP rs1136410 was genotyped by high-resolution melting analyses (HRM). PARP activities and 8-OHdG levels in peripheral blood mononuclear cells (PBMCs) were determined by ELISA kits.

RESULTS

In discovery, replication, and their merged sets, the variant genotypes (AG+GG) of SNP rs1136410 were significantly associated with an increased risk of ARC under a dominant model (Adjusted odds ratio (OR)=1.42, P_adj=0.001 for the merged set). This association was further identified in subtype analyses for cortical ARC (Adjusted OR=1.69, P_adj<0.001). In subgroup analyses, we identified a significant interaction between SNP rs1136410 and smoking habit in increasing ARC risk (P_inter=0.019). Moreover, ARC patients had lower activities of PARP and higher levels of 8-OHdG than controls. There were significant correlations of SNP rs1136410 with decreased PARP activities and increased 8-OHdG levels in controls and patients with cortical ARC.

CONCLUSIONS

This study suggests that SNP rs1136410 may confer susceptibility to ARC by affecting PARP activities and oxidative DNA damage.

Cadmium and lead exposure and risk of cataract surgery in U.S. adults

Cataract is a major cause of visual dysfunction and the leading cause of blindness. Elevated levels of cadmium and lead have been found in the lenses of cataract patients, suggesting these metals may play a role in cataract risk. This study aimed to examine the associations of blood lead, blood cadmium and urinary cadmium with cataract risk. We identified 9763 individuals aged 50 years and older with blood lead and cadmium levels, and a randomly selected subgroup of 3175 individuals with available urinary cadmium levels, from the National Health and Nutrition Examination Surveys (NHANES) from 1999 to 2008 (mean age=63years). Participants were considered to have cataract if they self-reported prior cataract surgery in NHANES's vision examination. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using survey logistic regression models. We identified 1737 cataract surgery cases (the weighted prevalence=14.1%). With adjustment for age, race/ethnicity, gender, education, diabetes mellitus, body mass index, cigarette smoking (serum cotinine and pack-years) and urine hydration, every 2-fold increase in urinary cadmium was associated with a 23% higher risk of cataract surgery (OR=1.23, 95% CI: 1.04, 1.46, p=0.021). We found no associations of cataract surgery with blood cadmium (OR=0.97, 95% CI: 0.89, 1.07) and blood lead (OR=0.97, 95% CI: 0.88, 1.06). Mediation analysis showed that for the smoking-cadmium-cataract pathway, the ratio of smoking's indirect effect to the total effect through cadmium was more than 50%. These results suggest that cumulative cadmium exposure may be an important under-recognized risk factor for cataract. However, these findings should be interpreted with a caution because of inconsistent results between urinary cadmium and blood cadmium.

Nuclear and Mitochondrial DNA of Age-Related Cataract Patients Are Susceptible to Oxidative Damage

PURPOSE

Reactive oxygen species caused by oxidative stress are considered as an important risk factor in the pathogenesis of age-related cataract (ARC). In addition, it has been shown that DNA damage has a potential role in the pathogenesis of cataract. In this study, background DNA damage, oxidative stress-induced DNA damage, and repair of nuclear and mitochondrial DNA of peripheral blood mononuclear cells (PBMCs) of ARC patients were investigated.

METHODS

The study population included 30 age-matched and sex-matched controls with 30 ARC patients aged 50 years and older. Acute oxidative stress was induced by 200 µM H₂O₂. The DNA damage was determined using gene-specific quantitative PCR-based assay in DNA extracted from PBMCs, both at basal condition and after (0, 6, and 20 h) acute oxidative stress.

RESULTS

Background level of mitochondrial DNA frequency was higher in cataract patients. The present study revealed that, for the first time, both nDNA and mtDNA of cataract patients were sensitive to the oxidative stress in comparison with healthy individuals. It was found that oxidative DNA damage in PBMCs was almost all repaired within 20 h. Also, time-dependent repair of nDNA and mtDNA damage was not different between cataract patients and healthy individuals.

CONCLUSIONS

Our findings clearly demonstrate that both nDNA and mtDNA in cataract patients are susceptible to oxidative DNA damage and background level of mitochondrial DNA damage was higher. Also, these results suggest that oxidative DNA damage accumulation (especially mtDNA damage) can play a crucial role in pathogenesis of cataract.

Hypertension potentiates cataractogenesis in rat eye through modulation of oxidative stress and electrolyte homeostasis

Purpose

To evaluate modes of cataractogenesis in the hypertensive state by using different hypertensive animal models, including fructose, cadmium chloride (CdCl₂), N_ω-nitro-l-arginine methyl ester (l-NAME), and two-kidney, one clip (2K1C) method.

Methods

Male Sprague–Dawley albino rats (150–180 g) were divided into different groups, each group containing six animals. Hypertension was induced in animals via six weeks administration of fructose (10% solution in drinking water), CdCl₂ (0.5 mg/kg/day, i.p.), and l-NAME (20 mg/kg/day, p.o.) in their respective groups and NaCl (0.9% solution in drinking water) in the 2K1C group. The Ramipril-treated group (2 mg/kg/day, orally) served as a standard group for the 2K1C animal model. Blood pressure was measured biweekly using non-invasive blood pressure system. The biochemical parameters in serum and eye lenses were evaluated after six weeks of the experimental protocol.

Results

Hypertensive animal models showed significant induction of systolic and diastolic blood pressure and modulation of oxidative stress through depletion of antioxidants, including glutathione peroxidase, catalase, superoxide dismutase, glutathione, and elevation of malondialdehyde in serum and eye lenses. A significant elevation of ionic contents (Na⁺ and Ca²⁺) and reduction of total protein and Ca²⁺ ATPase activity in eye lenses were observed in all hypertensive animal models except l-NAME when compared with the normal group. The significant restoration of the antioxidants, Malondialdehyde (MDA) total protein, and ionic contents in the eye lenses concomitant with reduction of blood pressure were observed in the ramipril-treated group as compared to the 2K1C animal model. The results indicate that the fructose, CdCl_2, and 2K1C models showed pronounced cataractogenic effects in the rat eye lenses.

Conclusion

Based on our findings, it can be concluded that systemic hypertension significantly increases the risk of cataract formation in the rat eyes via modulation of the antioxidant defense mechanism and electrolyte homeostasis.

Hydroxysafflor yellow A improves established monocrotaline-induced pulmonary arterial hypertension in rats

Objective

To evaluate the beneficial effects of hydroxysafflor yellow A (HSYA) on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats, and to investigate the main pathophysiological mechanism of HSYA in preventing development of MCT-induced PAH.

Methods

Four groups (control, control with HSYA treatment, MCT-exposed, and MCT-exposed with HSYA treatment) were evaluated at day 28 following MCT exposure. Haemodynamic measurements, right ventricular hypertrophy, morphometry, inflammatory cytokines and oxidant expression were assessed.

Results

HSYA significantly reduced haemodynamic changes, right ventricular hypertrophy and morphometric changes induced by exposure to MCT. HYSA also suppressed MCT-induced inflammation and oxidative stress in rat pulmonary tissue.

Conclusions

Experimental MCT-induced PAH may be reduced by HSYA treatment, and the mechanism may involve suppression of inflammation and oxidative stress.

The Polymorphisms with Cataract Susceptibility Impair the EPHA2 Receptor Stability and Its Cytoprotective Function

Despite accumulating evidence revealing susceptibility genes for age-related cataract, its pathophysiology leading to visual impairment at the cellular and molecular level remains poorly understood. Recent bioinformatic studies uncovered the association of two single nucleotide polymorphisms in human EPHA2, rs2291806 and rs1058371, with age-related cataract. Here we investigated the role of EPHA2 in counteracting oxidative stress-induced apoptosis of lens epithelial cells. The cataract-associated missense mutations resulted in the destabilization of EPHA2 receptor without altering the mRNA transcription. The cytoprotective and antiapoptotic function of EPHA2 in lens epithelial cells was abolished by the functional polymorphisms. Furthermore, our results suggest that the downstream signaling of activated EPHA2 promotes the antioxidative capacity of lens epithelial cells to eradicate the overproduction of reactive oxygen species. In contrast, the overexpression of EPHA2 with nonsynonymous mutations in the lens epithelial cells offered limited antioxidative protection against oxidative stress. Thus, our study not only sheds the light on the potential cytoprotective function of EPHA2 signaling in lens but also provides the cellular mechanisms underlying the pathogenesis of age-related cataract.

Acetylated 8-oxoguanine DNA glycosylase 1 and its relationship with p300 and SIRT1 in lens epithelium cells from age-related cataract

The human 8-oxoguanine-DNA glycosylase 1 (OGG1) is the major DNA glycosylase responsible for repair of 7,8-dihydro-8-oxoguanine (8-oxoG) and ring-opened fapyguanine, critical mutagenic DNA lesions that are induced by reactive oxygen species. OGG1 acetylation has been demonstrated playing an important role in response to DNA damage. Here, we investigated the relationship between acetylated OGG1 (Ac-OGG1) and ARC, and clarified the effect of p300 and SIRT1 on the 8-oxoG excision ability of OGG1 in ARC development. Our results showed that anterior lens capsules from ARC group had higher proportion of 8-oxoG positive LECs than those from control group. OGG1 mRNA and protein levels significantly increased in ARC group compared with control group, while the protein levels of Ac-OGG1 were lower in ARC group. We investigated the factors involved in OGG1 acetylation and found that p300 and SIRT1 are the major acetyltransferases for OGG1 acetylation. We also identified acetylation of K338/K341 lysine residues in OGG1 has an important role on the repair activity of OGG1 to oxidative damage after H2O2 exposure in human lens epithelial cells (HLE-B3). Taken together, these data demonstrate that OGG1 acetylation regulates its function in response to DNA damage and could be one of the mechanisms of ARC.

Correlation of oxidant status with oxidative tissue damage in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a debilitating autoimmune disease whose etiology remains unknown, but studies have consistently implicated a plethora of inflammatory mechanisms culminating in chronic symmetric and erosive synovitis. Importantly, reactive oxygen species (ROS) have been attributed to directly contribute towards the destructive, proliferative synovitis evident in RA. Accordingly, this study aimed to establish whether the degree of oxidative stress and disease activity score (DAS28) correlated with the downstream effects of oxidative damage. The redox status of neutrophils sourced from synovial fluid (SF) was measured by flow cytometry in terms of total ROS and hydroxyl radicals. Among the molecular damage markers, protein carbonylation and lipid peroxidation were detected by spectrophotometry and S-nitrosothiols by fluorimetry. Neutrophils constituted the major cellular component of the SF of patients with RA and their levels of ROS and hydroxyl radicals correlated strongly with protein carbonylation and lipid peroxidation. However, all the oxidative damage markers correlated positively with DAS28. Taken together, in patients with RA, the strong correlation between levels of ROS and DAS28 with markers of oxidative damage suggests that measurement of oxidative stress could serve as a biomarker for monitoring disease severity in RA.

DNA damage in lens epithelial cells and peripheral lymphocytes from age-related cataract patients

BACKGROUND

Oxidative DNA damage may be one of the etiologies of age-related cataract (ARC). We quantified DNA damage in lens epithelial cells (LECs) and peripheral blood lymphocytes of ARC.

METHODS

A total of 64 patients with different types of ARC and 23 control subjects were enrolled. Fresh LECs and peripheral lymphocytes were collected and DNA damage was evaluated by alkaline comet assay. The percentage of DNA in the tail of comets (%Tail DNA) and the olive tail moment (OTM) were calculated by CASP software.

RESULTS

The results showed the %Tail DNA and OTM in LECs and lymphocytes in the overall cataract patient group were significantly higher than those in the control subjects. The %Tail DNA and OTM of LECs and lymphocytes showed no differences among cortical, nuclear and posterior subcapsular cataracts. The %Tail DNA and OTM in LECs were significantly lower than those in lymphocytes but a significant correlation of the DNA damage was found between them.

CONCLUSION

We concluded that DNA damage in lens and peripheral blood lymphocytes increased in ARC. The results imply that local and systemic oxidative DNA damage might play certain roles in ARC pathogenesis.