Cataracts Abstracts 1

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A prospective study of carotenoid intake and risk of cataract extraction in US men.
            (Brown et al., 1999) Download
BACKGROUND:  Dietary antioxidants, including carotenoids, are hypothesized to decrease the risk of age-related cataracts by preventing oxidation of proteins or lipids within the lens. However, prospective epidemiologic data concerning this phenomenon are limited. OBJECTIVE:  Our objective was to examine prospectively the association between carotenoid and vitamin A intakes and cataract extraction in men. DESIGN:  US male health professionals (n = 36644) who were 45-75 y of age in 1986 were included in this prospective cohort study. Others were subsequently included as they became 45 y of age. A detailed dietary questionnaire was used to assess intake of carotenoids and other nutrients. During 8 y of follow-up, 840 cases of senile cataract extraction were documented. RESULTS:  We observed a modestly lower risk of cataract extraction in men with higher intakes of lutein and zeaxanthin but not of other carotenoids (alpha-carotene, beta-carotene, lycopene, and beta-cryptoxanthin) or vitamin A after other potential risk factors, including age and smoking, were controlled for. Men in the highest fifth of lutein and zeaxanthin intake had a 19% lower risk of cataract relative to men in the lowest fifth (relative risk: 0.81; 95% CI: 0.65, 1.01; P for trend = 0.03). Among specific foods high in carotenoids, broccoli and spinach were most consistently associated with a lower risk of cataract. CONCLUSIONS:  Lutein and zeaxanthin may decrease the risk of cataracts severe enough to require extraction, although this relation appears modest in magnitude. The present findings add support for recommendations to consume vegetables and fruit high in carotenoids daily.

Ascorbic acid content of human corneal epithelium.
            (Brubaker et al., 2000) Download
PURPOSE:  To measure the concentration of ascorbic acid in the human corneal epithelium. METHODS:  Corneal epithelium was removed from postmortem eyes 4 to 16 hours after death and ascorbate measured by high-performance liquid chromatography. RESULTS:  The concentration of ascorbate was 1.33 +/- 0.48 mg/gm wet weight (mean +/- SD), estimated to be 14 times its concentration in the aqueous humor. CONCLUSIONS:  Ascorbate can protect the basal layer of the epithelium by absorption of incident ultraviolet radiation.


A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women.
            (Chasan-Taber et al., 1999) Download
BACKGROUND:  Oxidation of lens proteins plays a central role in the formation of age-related cataracts, suggesting that dietary antioxidants may play a role in prevention. However, the relation between specific antioxidants and risk of cataract remains uncertain. OBJECTIVE:  Our objective was to examine prospectively the association between carotenoid and vitamin A intakes and cataract extraction in women. METHODS:  A prospective cohort of registered female nurses aged 45-71 y and free of diagnosed cancer was followed; in 1980, 50461 were included and others were added as they became 45 y of age for a total of 77466. Information on nutrient intake was assessed by repeated administration of a food-frequency questionnaire during 12 y of follow-up. RESULTS:  During 761762 person-years of follow-up, 1471 cataracts were extracted. After age, smoking, and other potential cataract risk factors were controlled for, those with the highest intake of lutein and zeaxanthin had a 22% decreased risk of cataract extraction compared with those in the lowest quintile (relative risk: 0.78; 95% CI: 0.63, 0.95; P for trend = 0.04). Other carotenoids (alpha-carotene, beta-carotene, lycopene, and beta-cryptoxanthin), vitamin A, and retinol were not associated with cataract in multivariate analysis. Increasing frequency of intakes of spinach and kale, foods rich in lutein, was associated with a moderate decrease in risk of cataract. CONCLUSIONS:  Lutein and zeaxanthin and foods rich in these carotenoids may decrease the risk of cataracts severe enough to require extraction.

alpha-Lipoic acid alters post-translational modifications and protects the chaperone activity of lens alpha-crystallin in naphthalene-induced cataract.
            (Chen et al., 2010) Download
PURPOSE:  To evaluate whether alpha-lipoic acid (LA) inhibits lens opacity of naphthalene-induced cataract by altering post-translational modifications (PTMs) and protecting the chaperone activity of alpha-crystallins. METHODS:  Forty-five Sprague-Dawley rats were divided into three groups: control, naphthalene, and naphthalene plus LA. Cataracts were induced by oral administration of 1 g naphthalene/kg body weight/day. Rats in the naphthalene plus LA group were also fed 30 mg LA/day. The development of naphthalene-initiated cataract was monitored every week by slit lamp microscopy for nine weeks, then the lens proteins were separated by HPLC, and peaks corresponding to alpha-crystallins were resolved on 2-DE. The spots of 2-DE were subjected to mass spectrometry to identify PTMs. Chaperone activity of alpha-crystallins was measured by heat-induced aggregation of betaL-crystallin. RESULTS:  The lenses of rats fed with naphthalene plus LA exhibited less light scattering than that fed with only naphthalene at three weeks after treatment (P < 0.01). C-terminal truncated alphaA crystallin was detected in naphthalene-induced cataract and was abrogated by LA treatment. Several other post-translational modifications were identified including methylation, phosphorylation, acetylation, carbamylation, and oxidation. CONCLUSIONS:  Our data are the first to show PTM changes induced by naphthalene in rat lenses. Our findings also indicate that LA can inhibit naphthalene-induced lens opacity by altering PTM and protecting the chaperone activity of alpha-crystallins.

Quercetin metabolism in the lens: role in inhibition of hydrogen peroxide induced cataract.
            (Cornish et al., 2002) Download
Oxidative stress is implicated in the initiation of maturity onset cataract. Quercetin, a major flavonol in the diet, inhibits lens opacification in a lens organ culture oxidative model of cataract. The aim of this research was to investigate the metabolism of quercetin in the lens and show how its metabolism affects the ability to prevent oxidation-induced opacity. The LOCH model (Free Radical Biology & Medicine 26:639; 1999) was employed, using rat lenses to investigate the effects of quercetin and metabolites on hydrogen peroxide-induced opacification. High-performance liquid chromatography analysis showed that the intact rat lens is capable of converting quercetin aglycone to 3'-O-methyl quercetin (isorhamnetin). Over a 6 h culture period no further metabolism of the 3'-O-methyl quercetin occurred. Loss of quercetin in the lens was accounted for by the increase in 3'-O-methyl quercetin. Incubation with 3,5-dinitrocatechol (10 microM), a catechol-O-methyltransferase (COMT) inhibitor, prevented the conversion of quercetin to 3'-O-methyl quercetin. The presence of both membrane-bound and soluble COMT was confirmed by immunoblotting. The results demonstrate that in the rat lens COMT methylates quercetin and that the product accumulates within the lens. Quercetin (10 microM) and 3'-O-methyl quercetin (10 microM) both inhibited hydrogen peroxide- (500 microM) induced sodium and calcium influx and lens opacification. Incubation of lenses with quercetin in the presence of COMT inhibitor revealed that the efficacy of quercetin is not dependent on its metabolism to 3'-O-methyl quercetin. The results indicate dietary quercetin and metabolites are active in inhibiting oxidative damage in the lens and thus could play a role in prevention of cataract formation.

Relationships between hormonal status and cataract in french postmenopausal women: the POLA study
            (Defay et al., 2003) Download
PURPOSE: Prevalence rate of cataract is higher in women than in men. Sex hormones have been hypothesized to be linked with this gender difference. Our aim is to study the relationships between hormonal status and cataract in postmenopausal women. METHODS: The Pathologies Oculaires Liees a l'Age (POLA) study is a population-based study on age-related eye diseases and their risk factors, in 2584 residents of Sete (France). Cataract classification was based on a standardized lens examination, according to Lens Opacities Classification System III. Biological measurements were performed from fasting blood samples. We conducted a cross-sectional study in the female participants (n=1451) aged over 60 years. RESULTS: No association of hormone replacement therapy (HRT) with any type of cataract was found, but an increased risk of cataract surgery was observed in women with a long duration of hormone therapy >/=5 years) (multivariate-adjusted odds ratio (OR)=3.80; 95% CI: 1.45-9.94). Globally, the risk for cataract (any type) was not associated with a long duration of HRT use (OR=1.06; 95% CI: 0.64-1.74). After multivariate adjustment, oophorectomy was associated with a reduced risk of cataract (OR=0.60; 95% CI=0.38-0.94). In the multivariate model, no association was found between estradiol, total testosterone or sex-hormone-binding globulin and cataract. However, high levels of dehydroepiandrosterone sulfate (DHEAS) were associated with a reduced risk of cataract (OR=0.79; 95% CI: 0.63-0.99). CONCLUSION: HRT use was not associated with cataract. A reduced risk of cataract was found in oophorectomized women and in women with high DHEAS levels.

Quercetin inhibited epithelial mesenchymal transition in diabetic rats, high-glucose-cultured lens, and SRA01/04 cells through transforming growth factor-β2/phosphoinositide 3-kinase/Akt pathway.
            (Du et al., 2017) Download
Diabetic cataract (DC), an identified life-threatening secondary complication of diabetes mellitus, has proven to be a dilemma because of its multifactorial caused and progression. An increasing number of studies have shown that in addition to the maillard reaction, enhanced polyol pathway, and oxidative insults, epithelial mesenchymal transition (EMT) is related to the prevalence of DC. Quercetin, a classic flavonoid with multiple pharmacological effects has been reported to possess therapeutic efficacy in the management and treatment of this disease. However, the mechanism underlying its therapeutic efficacy in EMT of lens epithelial cells (SRA01/04) and contribution to resolving DC remains a mystery. Therefore, in this study, we investigated the effects of quercetin on EMT of SRA01/04 and high-glucose (HG)-induced lens opacity accompanied by lens fibrosis induced by type-1 diabetes. Furthermore, we sought to clarify the specific mechanisms underlying these effects. At week 14 after streptozotocin (STZ) intraperitoneal administration, diabetic rats showed lens opacity accompanied with diminished antioxidant function, enhanced polyol pathway activity, and non-enzymatic glycation. Western blotting confirmed EMT in rat SRA01/04 cells with significantly increased α-smooth muscle actin (α-SMA) and decreased E-cadherin expressions. Treatment of the lens with quercetin ameliorated the oxidative stress, inhibited aldose reductase (AR) activation, reduced advanced glycation end product (AGE) production, and finally suppressed EMT in the early stages. Our in vitro results showed that high-glucose activated the transforming growth factor-β2/phosphoinositide 3-kinase/protein kinase B (TGF-β2/PI3K/Akt) signalling and EMT in SRA01/04 cells. Further, induced oxidative stress, activation of aldose reductase, and accumulation of advanced glycation end products were also involved in this process. Quercetin was potent enough to effectively ameliorate the high glucose (HG)-induced EMT of SRA01/04 cells by inhibiting the activation of TGF-β2/PI3K/Akt, enhancing the antioxidant capacity, inhibiting AR activity, and reducing AGE production. From the whole animal to tissues, and finally the cellular level, our results provide considerable evidence of the therapeutic potential of quercetin for DC. This might be due to its inhibition of EMT mediated through inhibition of the TGF-β/PI3K/Akt pathway.

Associations between plasma levels of vitamins and cataract in the Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS): CTNS Report #2.
            (Ferrigno et al., 2005) Download
PURPOSE:  To investigate the association at baseline between plasma levels of selected vitamins and the presence and type of cataract in the participants in The Italian-American Trial of Nutritional Supplements and Age-related Cataract. METHODS:  At baseline, the participants (1020, 710 with "early cataract" and 310 with "no cataract," 55-75 years of age) received an ocular examination, photographic lens grading, and measurement of plasma levels of vitamins A, C, E, beta-carotene, and of red blood cell glutathione reductase activity. RESULTS:  In multiple logistic models adjusted for potential confounders, high vitamin C levels were associated with a protective effect on nuclear (N) [OR: 0.54; 95% CI: 0.30, 0.97] and posterior subcapsular (PSC) cataract (OR: 0.37; 95% CI: 0.15, 0.93). High vitamin E levels were associated with increased prevalence of cortical cataract (C) (OR: 1.99; 95% CI: 1.02-3.90), PSC (OR: 3.27; 95% CI: 1.34, 7.96) and of any cataract (OR: 1.86; 95% CI: 1.08, 3.18). CONCLUSIONS:  In agreement with some earlier studies, we found higher plasma levels of vitamin C to be associated with reduced prevalence of N and PSC cataracts. The finding of an increased prevalence of some types of cataract with higher levels of vitamin E was unexpected, has not been previously reported, and could be due to unadjusted confounding.

Long-term vitamin C supplement use and prevalence of early age-related lens opacities.
            (Jacques et al., 1997) Download
We designed the present study to examine the cross-sectional relation between age-related lens opacities and vitamin C supplement use over a 10-12-y period before assessment of lens status in women without diagnosed cataract or diabetes. This design avoids biased measurement of nutrient intake that results when knowledge of lens opacities influences nutrition-related behavior or its reporting. The participants were 247 Boston-area women aged 56-71 y selected from the Nurses' Health Study cohort with oversampling of women with high or low vitamin C intakes. Lens opacities were graded with the Lens Opacification Classification System II. Use of vitamin C supplements for > or = 10 y (n = 26) was associated with a 77% lower prevalence of early lens opacities (odds ratio: 0.23; 95% CI: 0.09, 0.60) at any lens site and a 83% lower prevalence of moderate lens opacities (odds ratio: 0.17; 95% CI: 0.03, 0.85) at any lens site compared with women who did not use vitamin C supplements (n = 141) after adjustment for age and other potentially confounding variables. Women who consumed vitamin C supplements for < 10 y showed no evidence of a reduced prevalence of early opacities. These data, together with data from earlier experimental and epidemiologic studies, suggest that long-term consumption of vitamin C supplements may substantially reduce the development of age-related lens opacities.

Comparative study of plasma ascorbic acid levels in senile cataract patients and in normal individuals
            (Jalal et al., 2009) Download
OBJECTIVE: Dietary antioxidant vitamins, in particular vitamin C, could play a role in preventing the onset or progression of age-related visual impairment. The aim of this study was to determine the plasma ascorbic acid levels in normal individuals and in senile cataract patients. METHOD: The test group included 50 cataract patients, while the control group members were selected among medical staff and patients' companions after age matching with the test group. Questionnaire forms contained age, sex, and location of residency (urban or rural) inquiries. Five milliliters of drawn blood was centrifuged, and plasma ascorbic acid level was measured by spectrophotometer. Statistical analysis of plasma ascorbic acid concentrations were done by paired test. RESULTS: The mean plasma ascorbic acid level in the test group was 0.96 +/- 0.08 mg/dl and 1.12 +/- 0.15 mg/dl in the control group. Ascorbic acid level in the test group was significantly lower than the control group and p value = 0.00001. Aging had a reverse relation with plasma ascorbic acid level in males, while it showed no significant alterations in females. Rural compared with urban and females compared to males showed higher levels of plasma ascorbic acid. CONCLUSION: This study revealed that plasma ascorbic acid level in cataract patients was lower than normal individuals. Antioxidant vitamins, in particular vitamin C, found in Mediterranean fruits and vegetables, can help with the prevention of cataracts, which is a major health service burden in many countries.

Effects of two antioxidants; α-lipoic acid and fisetin against diabetic cataract in mice.
            (Kan et al., 2015) Download
The purpose of this study was to determine whether α-lipoic acid and fisetin have protective effects against cataract in a streptozotocin-induced experimental cataract model. Twenty-eight male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). Three weeks after induction of diabetes, mice were divided randomly into 4 groups in which each group contained 7 mice; fisetin-treated group (group 1), α-lipoic acid-treated group (group 2), fisetin placebo group (group 3), α-lipoic acid placebo group (group 4). Fisetin and α-lipoic acid were administered intraperitoneally weekly for 5 weeks. Cataract development was assessed at the end of 8 weeks by slit lamp examination, and cataract formation was graded using a scale. All groups developed at least grade 1 cataract formation. In the fisetin-treated group, the cataract stages were significantly lower than in the placebo group (p = 0.02). In the α-lipoic acid-treated group, the cataract stages were lower than in the placebo group but it did not reach to a significant value. Both fisetin and α-lipoic acid had a protective effect on cataract development in a streptozotocin-induced experimental cataract model. The protective effect of fisetin appears as though more effective than α-lipoic acid.

A link between maternal malnutrition and depletion of glutathione in the developing lens: a possible explanation for idiopathic childhood cataract
            (Kumar et al., 2013) Download
Lens cataract is the leading cause of blindness in developing countries. While cataract is primarily a disease of old age and is relatively rare in children, accounting for only four per cent of global blindness, childhood cataract is responsible for a third of the economic cost of blindness. While many of the causes of cataract in children are known, over half of childhood cataracts are idiopathic with no known cause. The incidence of idiopathic cataract is highest in developing countries and studies have discovered that low birth weight is a risk factor in the development of idiopathic childhood cataract. As low birth weight is a reflection of poor foetal growth, it is possible that maternal malnutrition, which is endemic in some developing countries, results in the altered physiology of the foetal lens. We have conducted a review of the literature that provides evidence for a link between maternal malnutrition, low birth weight and the development of childhood cataract. Using our accumulated knowledge on the pathways that deliver nutrients to the adult lens, we propose a cellular mechanism, by which oxidative stress caused by maternal malnutrition affects the development of antioxidant defence pathways in the embryonic lens, leading to an accelerated onset of nuclear cataract in childhood.

The Lens Opacities Case-Control Study. Risk factors for cataract.
            (Leske et al., 1991) Download
The Lens Opacities Case-Control Study evaluated risk factors for age-related nuclear, cortical, posterior subcapsular, and mixed cataracts. The 1380 participants were ophthalmology outpatients, aged 40 to 79 years, classified into the following groups: posterior subcapsular only, 72 patients; nuclear only, 137 patients; cortical only, 290 patients; mixed cataract, 446 patients; and controls, 435 patients. In polychotomous logistic regression analyses, low education increased risk (odds ratio [OR] = 1.46) and regular use of multivitamin supplements decreased risk (OR = 0.63) for all cataract types. Dietary intake of riboflavin, vitamins C, E, and carotene, which have antioxidant potential, was protective for cortical, nuclear, and mixed cataract; intake of niacin, thiamine, and iron also decreased risk. Similar results were found in analyses that combined the antioxidant vitamins (OR = 0.40) or considered the individual nutrients (OR = 0.48 to 0.56). Diabetes increased risk of posterior subcapsular, cortical, and mixed cataracts (OR = 1.56). Oral steroid therapy increased posterior subcapsular cataract risk (OR = 5.83). Females (OR = 1.51) and nonwhites (OR = 2.03) were at increased risk only for cortical cataract. Risk factors for nuclear cataract were a nonprofessional occupation (OR = 1.96), current smoking (OR = 1.68), body mass index (OR = 0.76), and occupational exposure to sunlight (OR = 0.61). Gout medications (OR = 2.48), family history (OR = 1.52), and use of eyeglasses by age 20 years, which is an indicator of myopia (OR = 1.44), increased risk of mixed cataract. The results support a role for the nutritional, medical, personal, and other factors in cataractogenesis. The potentially modifiable factors suggested by this study merit further evaluation.

Alpha lipoic acid protects lens from H(2)O(2)-induced cataract by inhibiting apoptosis of lens epithelial cells and inducing activation of anti-oxidative enzymes.
            (Li et al., 2013) Download
OBJECTIVE:  To determine whether alpha lipoic acid (LA) can effectively protect lenses from hydrogen peroxide (H2O2)-induced cataract. METHODS:  Lens from adult Sprague-Dawley rats were cultured in 24-well plates and treated without or with 0.2 mM of H2O2, 0.2 mM of H2O2 plus 0.5 mM, 1.0 mM, or 2.0 mM of LA for 24 h. Cataract was assessed using cross line grey scale measurement. Superoxide dismutase (SOD), glutathione (GSH-Px), lactate dehydrogenase (LDH), and malondialdehyde (MDA) activity or level in lens homogenates was measured. Apoptosis of lens epithelial cells in each group were detected by Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling (TUNEL) Assay. RESULTS:  A total of 0.2 mM of H2O2 induced obvious cataract formation and apoptosis in lens' epithelial cells, but 0.5-2.0 mM of LA could block the effect of 0.2 mM H2O2 in inducing cataract and apoptosis. Furthermore, 0.2 mM of H2O2 significantly decreased SOD, GSH-Px, and LDH activity and significant increased MDA level in the lens, but 0.5-2.0 mM of LA blocked the effect of 0.2 mM H2O2. One mM of LA was found to be the most effective. CONCLUSIONS:  LA can protect lens from H2O2-induced cataract. LA exerts protective effects through inhibition of lens' epithelial cell apoptosis and activation of anti-oxidative enzymes.

Association between lutein and zeaxanthin status and the risk of cataract: a meta-analysis.
            (Liu et al., 2014) Download
The purpose of this meta-analysis was to evaluate the relationship between blood lutein and zeaxanthin concentration and the risk of age-related cataract (ARC). MEDLINE, EMBASE, ISI and Cochrane Library were searched to identify relevant studies up to April 2013. Meta-analysis was conducted to obtain pooled relative risks (RRs) for the highest-versus-lowest categories of blood lutein and zeaxanthin concentrations. One cohort study and seven cross-sectional studies were included in the meta-analysis. There were significant inverse associations between nuclear cataract and blood lutein and zeaxanthin concentrations, with the pooled RRs ranging from 0.63 (95% confidence interval (CI): 0.49, 0.77) for zeaxanthin to 0.73 (95% CI: 0.59, 0.87) for lutein. A stronger association between nuclear cataract and blood zeaxanthin might be noted for the studies conducted in the European Nations. Blood lutein and zeaxanthin were also noted to lead towards a decrease in the risk of cortical cataract and subcapsular cataract; however, these pooled RRs were not statistically significant, with the exception of a marginal association between lutein and subcapsular cataract. Our results suggest that high blood lutein and zeaxanthin are significantly associated with a decrease in the risk of nuclear cataract. However, no significant associations were found for ARC in other regions of the lens.

A dose-response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract.
            (Ma et al., 2014) Download
BACKGROUND:  Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. We aimed to conduct a meta-analysis of prospective cohort studies to examine the association between dietary lutein and zeaxanthin intake and risk of age-related cataract (ARC). METHODS:  We systematically searched MEDLINE, EMBASE, Web of Science, and Cochrane Library databases up to March 2013. Reference lists from retrieved articles were also reviewed. The adjusted relative risks (RRs) from each study were extracted to calculate a pooled estimate with its 95 % confidence interval (CI). The dose-response relationships were assessed by using generalized least-squares trend estimation. RESULTS:  Six prospective cohort studies were identified involving 4,416 cases and 41,999 participants. For the comparison between the highest and the lowest categories of dietary lutein and zeaxanthin intake, significant inverse association were found for nuclear cataract (RR: 0.75; 95 % CI: 0.65, 0.85), but not for cortical cataract (RR: 0.85; 95 % CI: 0.53, 1.17) and for posterior subcapsular cataract (RR: 0.77; 95 % CI: 0.40, 1.13). Dose-response analysis showed that every 300 μg/d increment in dietary lutein and zeaxanthin intake was associated with a 3 %, 1 %, or 3 % reduction in the risk of nuclear cataract (RR: 0.97; 95 % CI: 0.94, 0.99), cortical cataract (RR: 0.99; 95 % CI: 0.95, 1.02), or posterior subcapsular cataract (RR: 0.97; 95 % CI: 0.93, 1.01) respectively. CONCLUSIONS:  Dietary lutein and zeaxanthin intake is associated with a reduced risk of ARC, especially nuclear cataract in a dose-response manner, indicating a beneficial effect of lutein and zeaxanthin in ARC prevention.


 

Lens cadmium, lead, and serum vitamins C, E, and beta carotene in cataractous smoking patients
            (Mosad et al., 2010) Download
PURPOSE: To investigate the association between smoking and subcapsular cataract and blood levels of cadmium and lead, and serum levels of vitamins C, E, and beta carotene in the middle-age male population. SUBJECTS AND METHODS: The present study comprised 60 cataractous male patients aged 44-55 years who attended Mansoura University Ophthalmic Center. They were divided into two groups: the first group was comprised of 15 patients who had never smoked before with minimal exposure to cigarette smoking (control group), while the second group was comprised of 45 age and body mass index-matched smokers. Blood cadmium and lead concentrations were measured and their levels in the cataractous lenses were also estimated. The levels of some antioxidants, such as serum vitamins C, E, and beta carotene, were determined. RESULTS: Cadmium had a statistically significant higher concentration in blood and lenses of smokers compared with that of non smokers (p < 0.0001). There was a significantly high accumulation of cadmium in the lenses of cataractous smokers reaching about a four-fold increase in heavy smokers (15.4 +/- 0.4 micromol/g) and nearly a three-fold increase in light smokers (10.1 +/- 0.4 micromol/g) when compared to that of nonsmokers (3.7 +/- 0.9 micromol/g). Regarding vitamins E, C, and beta carotene, a highly significant reduction was observed in smokers when compared with nonsmokers. There was a highly positive correlation between blood cadmium concentrations and lens cadmium levels, and blood lead concentrations and lens lead levels in heavy smokers. CONCLUSION: Cadmium present in high concentrations among smokers was associated with the presence of cataracts, through induction of oxidative stress as evidenced by reduction of levels of some antioxidant studied in this work, such as vitamins E, C, and beta carotene. Thus, education of health care professionals and the public about the cataractogenic effect of cadmium is mandatory. Intake of various antioxidants may be helpful in reducing the risk of cataract formation.

 


References

Cornish, KM, G Williamson, and J Sanderson (2002), ‘Quercetin metabolism in the lens: role in inhibition of hydrogen peroxide induced cataract.’, Free Radic Biol Med, 33 (1), 63-70. PubMed: 12086683
Brown, L, et al. (1999), ‘A prospective study of carotenoid intake and risk of cataract extraction in US men.’, Am J Clin Nutr, 70 (4), 517-24. PubMed: 10500021
Brubaker, RF, et al. (2000), ‘Ascorbic acid content of human corneal epithelium.’, Invest Ophthalmol Vis Sci, 41 (7), 1681-83. PubMed: 10845585
Chasan-Taber, L, et al. (1999), ‘A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women.’, Am J Clin Nutr, 70 (4), 509-16. PubMed: 10500020
Chen, Y, et al. (2010), ‘alpha-Lipoic acid alters post-translational modifications and protects the chaperone activity of lens alpha-crystallin in naphthalene-induced cataract.’, Curr Eye Res, 35 (7), 620-30. PubMed: 20597648
Defay, R., et al. (2003), ‘Relationships between hormonal status and cataract in french postmenopausal women: the POLA study’, Ann Epidemiol, 13 (9), 638-44. PubMed: 14732303
Du, L, et al. (2017), ‘Quercetin inhibited epithelial mesenchymal transition in diabetic rats, high-glucose-cultured lens, and SRA01/04 cells through transforming growth factor-β2/phosphoinositide 3-kinase/Akt pathway.’, Mol Cell Endocrinol, 452 44-56. PubMed: 28501572
Ferrigno, L, et al. (2005), ‘Associations between plasma levels of vitamins and cataract in the Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS): CTNS Report #2.’, Ophthalmic Epidemiol, 12 (2), 71-80. PubMed: 16019690
Jacques, PF, et al. (1997), ‘Long-term vitamin C supplement use and prevalence of early age-related lens opacities.’, Am J Clin Nutr, 66 (4), 911-16. PubMed: 9322567
Jalal, D., F. Koorosh, and H. Fereidoun (2009), ‘Comparative study of plasma ascorbic acid levels in senile cataract patients and in normal individuals’, Curr Eye Res, 34 (2), 118-22. PubMed: 19219683
Kan, E, et al. (2015), ‘Effects of two antioxidants; α-lipoic acid and fisetin against diabetic cataract in mice.’, Int Ophthalmol, 35 (1), 115-20. PubMed: 25488016
Kumar, D, JC Lim, and PJ Donaldson (2013), ‘A link between maternal malnutrition and depletion of glutathione in the developing lens: a possible explanation for idiopathic childhood cataract’, Clin Exp Optom, 96 (6), 523-28. PubMed: 23800298
Leske, MC, LT Chylack, and SY Wu (1991), ‘The Lens Opacities Case-Control Study. Risk factors for cataract.’, Arch Ophthalmol, 109 (2), 244-51. PubMed: 1993036
Li, Y, et al. (2013), ‘Alpha lipoic acid protects lens from H(2)O(2)-induced cataract by inhibiting apoptosis of lens epithelial cells and inducing activation of anti-oxidative enzymes.’, Asian Pac J Trop Med, 6 (7), 548-51. PubMed: 23768827
Liu, XH, et al. (2014), ‘Association between lutein and zeaxanthin status and the risk of cataract: a meta-analysis.’, Nutrients, 6 (1), 452-65. PubMed: 24451312
Ma, L, et al. (2014), ‘A dose-response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract.’, Graefes Arch Clin Exp Ophthalmol, 252 (1), 63-70. PubMed: 24150707
Mosad, S. M., et al. (2010), ‘Lens cadmium, lead, and serum vitamins C, E, and beta carotene in cataractous smoking patients’, Curr Eye Res, 35 (1), 23-30. PubMed: 20021251