4-hydroxy-2-nonenal and Cataract

Diabetic retinopathy (DRP) is the formation of edema and small vessels in the retina due to high blood glucose levels. Asprosin is a hormone that stimulates the release of glucose from the liver into the circulation. Considering the relationship between oxidative stress and DRP, our study aimed to determine the levels of the oxidative stress markers 4-hydroxynonenal (4-HNE) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), as well as asprosin, in the blood and aqueous humor (Aq) of patients with and without DRP.. Thirty patients with single-eye DRP and cataract (DRP + C), 30 patients with diabetes mellitus and cataract without DRP (DM + C), and 30 healthy control (CON) participants were enrolled into this retrospective study. Except for healthy controls, Aq and blood samples were taken from these patients during their cataract operation. Asprosin, 4-HNE, and 8-OHdG concentrations were analyzed using enzyme-linked immunosorbent assays.. In patients with DRP, the levels of asprosin, 4-HNE, and 8-OHdG were significantly higher in both Aq and blood samples compared with the group of patients without DRP.. These findings suggest that the measurement of asprosin, 4-HNE, and 8-OHdG levels may support clinicians in determining the risk of DRP development.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Aldehydes; Aqueous Humor; Biomarkers; Cataract; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Female; Fibrillin-1; Humans; Male; Middle Aged; Oxidative Stress; Retrospective Studies

The Na⁺-H⁺-exchanger-1 (NHE-1) controls intracellular pH and glycolytic enzyme activities, and its expression and activity are increased by diabetes and high glucose. NHE-1-dependent upregulation of the upper part of glycolysis, under conditions of inhibition (lens) or insufficient activation (retina) of glyceraldehyde 3-phosphate dehydrogenase, underlies diversion of the excessive glycolytic flux towards several pathways contributing to oxidative stress, a causative factor in diabetic cataractogenesis and retinopathy. This study evaluated the role for NHE-1 in diabetic cataract formation and retinal oxidative stress and apoptosis. Control and streptozotocin-diabetic rats were maintained with or without treatment with the NHE-1 inhibitor cariporide (Sanofi-Aventis, 10 mgkg-1d-1) for 3.5 months. In in vitro studies, bovine retinal pericytes and endothelial cells were cultured in 5 or 30 mM glucose, with or without 10 µM cariporide, for 7 days. A several-fold increase of the by-product of glycolysis, α-glycerophosphate, indicative of activation of the upper part of glycolysis, was present in both rat lens and retina at an early (1-month) stage of streptozotocin-diabetes. Cariporide did not affect diabetic hyperglycemia and counteracted lens oxidative-nitrative stress and p38 MAPK activation, without affecting glucose or sorbitol pathway intermediate accumulation. Cataract formation (indirect ophthalmoscopy and slit-lamp examination) was delayed, but not prevented. The number of TUNEL-positive cells per flat-mounted retina was increased 4.4-fold in diabetic rats (101 ± 17 vs. 23 ± 8 in controls , P<0.01), and this increase was attenuated by cariporide (45 ± 12, P<0.01). Nitrotyrosine and poly(ADP-ribose) fluorescence and percentage of TUNEL-positive cells were increased in pericytes and endothelial cells cultured in 30 mM glucose, and these changes were at least partially prevented by cariporide. In conclusion, NHE-1 contributes to diabetic cataract formation, and retinal oxidative-nitrative stress and apoptosis. The findings identify a new therapeutic target for diabetic ocular complications.

Topics: Aldehydes; Animals; Apoptosis; Blood Glucose; Blotting, Western; Cataract; Cattle; Diabetes Complications; Extracellular Signal-Regulated MAP Kinases; Fasting; Guanidines; In Situ Nick-End Labeling; Lens, Crystalline; Male; Nitrosation; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Poly(ADP-ribose) Polymerases; Rats; Rats, Wistar; Retina; Sodium-Hydrogen Exchangers; Sulfones; Tyrosine

Oxidative stress plays a critical role in cataractogenesis, the leading cause of blindness worldwide. Since transition metals generate reactive oxygen species (ROS) formation, metal chelation therapy has been proposed for treatment of cataracts. However, the effectiveness of most chelators is limited by low tissue penetrability. This study is the first to demonstrate that the topically applied divalent metal chelator ethylenediamine tetraacetic acid (EDTA) combined with the carrier and permeability enhancer methyl sulfonyl methane (MSM) ameliorates both oxidation-induced lens opacification and the associated toxic accumulation of protein-4-hydroxynonenal (HNE) adducts. Both in vitro (rat lens culture) and in vivo (diabetic rats), EDTA-MSM (1) significantly reduced lens opacification by about 40-50%, (2) significantly diminished lens epithelial cell proliferation and fiber cell swelling in early stages of cataract formation in vivo, and (3) notably decreased the levels of protein-HNE adducts. These findings have important implications specifically for the treatment of cataract and generally for other diseases in which oxidative stress plays a key pathogenic role.

Topics: Administration, Topical; Aldehydes; Animals; Cataract; Cell Proliferation; Chelating Agents; Chelation Therapy; Diabetes Complications; Dimethyl Sulfoxide; Disease Models, Animal; Dose-Response Relationship, Drug; Edetic Acid; Epithelial Cells; Lens, Crystalline; Male; Metals; Oxidation-Reduction; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Sulfones

To study the metabolism of 4-hydroxynonenal (HNE), one of lipid derived aldehydes (LDAs), in diabetic rat lens and its role in diabetic cataract formation.. Experimental research. A factor design was used to set up the experiment statistically upon two factors: diabetic and normal control as treatment factors; day 30, 45 and 70 as the time factors. Normal and diabetic rats' lenses were incubated with HNE for 2 hours. HNE metabolites in the culture media were studied by high performance liquid chromatography (HPLC). Aldehyde dehydrogenase (ALDH) activity in normal and diabetic rat lens (30, 45 and 70 d after inducing of cataract) was detected by a spectrophotometer, ALDH protein and HNE-protein were detected by Western Blot. All data were analyzed by the Bonferroni test using SAS 8.0 software.. The major pathway for HNE metabolism in normal lens was conjugation with glutathione (GSH) to form GS-HNE (45%), followed by HNE's oxidation to 4-hydroxy-2-nonenoic acid (HNA) by ALDH, which accounted for approximately 9.1% of HNE. The conjugation of HNE with GSH in diabetic lens was decreased approximately 64% at day 30 compared with the controls (F = 49.59, P < 0.001). The pathway of HNE oxidation by ALDH in the diabetic lens was enhanced approximately 1.7 times at day 70 compared to day 30 (F = 11.51, P = 0.0442). A higher ALDH activity, greater amount of ALDH protein, and less amount of HNE-protein adduct were presented in diabetic rat lens.. The pathway of conjugation of HNE with GSH is inhibited in diabetic lens which may play a role in the formation of diabetic cataract. The oxidation of HNE by ALDH is a compensation process for protecting the lens against diabetic damage.

Topics: Aldehyde Dehydrogenase; Aldehydes; Animals; Cataract; Diabetes Complications; Oxidation-Reduction; Rats; Rats, Sprague-Dawley

4-Hydroxynonenal (HNE), a metastable lipid peroxidation product, is highly toxic to various cell types if not detoxified. Because of its constant exposure to light, the ocular lens continuously generates reactive oxygen species which, under conditions of oxidative stress, may lead to excessive lipid peroxidation and consequent formation of lipid-derived aldehydes (LDAs) such as HNE. The contribution of various isozymes of aldehyde dehydrogenase (ALDH) to the oxidation of LDAs has never been systematically investigated in the lens. The present study was undertaken to ascertain the role of ALDH1A1 and -3A1 in HNE metabolism and HNE-induced toxicity in cultured human lens epithelial cells (HLECs) and in rat and mouse lenses.. The metabolism of 3H-HNE was studied in ALDH3A1-knockout mouse lens and in HLECs transfected with ALDH1A1- or -3A1-specific antisense RNA and short interfering (Si)RNA. Appropriate controls were used, including wild-type mouse lens, scrambled oligonucleotides, and a transfection reagent. Transfected HLECs were exposed to oxidative stress (Fenton reaction) or HNE (30 microM) for 3 hours. Toxicity parameters, such as cell viability, apoptosis, and protein-HNE adducts and oxidation of exogenously added 3H-HNE were measured. Rat lenses were transfected with the SiRNA specific to ALDH1A1, and oxidation of 3H-HNE and the susceptibility of the transfected lenses to oxidation-induced opacification were measured.. Rat lenses transfected with ALDH1A1-specific SiRNA, or cultured in the presence of the ALDH inhibitor cyanamide/disulfiram and subjected to oxidative stress displayed accelerated loss of transparency and a diminished capacity to oxidize HNE. Similarly, inhibition of ALDH1A1 in HLECs by ALDH1A1-specific antisense RNA or SiRNA was associated with decreased oxidation of 3H-HNE and increased susceptibility of the cells to oxidative damage, including apoptosis. Furthermore, 3H-HNE metabolism and HNE-induced toxicity were not affected in ALDH3A1-specific SiRNA- or antisense RNA-treated rat lenses, HLECs, or ALDH3A1-null mouse lenses.. The results suggest that, under oxidative stress, HNE produced in the lens epithelium can cause toxicity and thus contribute to oxidation-induced cataractogenesis. Furthermore, the studies indicate that ALDH1A1 is a critical isozyme for maintaining clarity in human, rat, and mouse lenses.

Topics: Aldehyde Dehydrogenase; Aldehydes; Animals; Apoptosis; Cataract; Cell Survival; Cells, Cultured; Chromatography, High Pressure Liquid; Enzyme Inhibitors; Epithelial Cells; Gas Chromatography-Mass Spectrometry; Humans; Inactivation, Metabolic; Isoenzymes; Lens, Crystalline; Mice; Mice, Knockout; Oxidative Stress; Rabbits; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Antisense; RNA, Small Interfering; Transfection

Previous studies suggest oxygen free radicals' involvement in the etiology of cardiomyopathy with cataracts. To investigate the role of free radicals in the pathogenesis of the cardiomyopathy with cataracts and complex I deficiency, fibroblasts from patients were assessed for hydroxyl radical formation and aldehydic lipid peroxidation products with and without redox active agents that increase free radicals. The rate of hydroxyl radical formation in patient cells was increased over 2-10-fold under basal conditions, and up to 20-fold after menadione or doxorubicin treatment compared with normal cells. We also found an overproduction of aldehydes in patient cells both under basal conditions and after treatment. Both hydroxyl radicals and toxic aldehydes such as hexanal, 4-hydroxynon-2-enal, and malondialdehyde were elevated in cells from patients with three types of complex I deficiency. In contrast, acyloins, the less toxic conjugated products of pyruvate and saturated aldehydes, were lower in the patient cells. Our data provide direct evidence for the first time that complex I deficiency is associated with excessive production of hydroxyl radicals and lipid peroxidation. The resultant damage may contribute to the early onset of cardiomyopathy and cataracts and death in early infancy in affected patients with this disease.

Topics: Aldehydes; Cardiomyopathies; Cataract; Cells, Cultured; Fatal Outcome; Female; Fibroblasts; Humans; Hydroxyl Radical; Infant, Newborn; Lipid Peroxidation; Malondialdehyde; NAD(P)H Dehydrogenase (Quinone); Skin

We have previously shown that 4-hydroxynonenal (4-HNE) causes opacification of cultured rat lenses and that a novel group of glutathione S-transferases (GSTs) exhibit high specific activity towards 4-HNE. Previous studies have shown that t-butylated hydroxy toluene (BHT) induced GSTs in cultured rat lens. Therefore, the purpose of the present studies was to investigate if the opacification of rat lenses exposed to 4-HNE is ameliorated by pre-culturing the lenses in media containing BHT.. Rat lenses were divided into four groups. Group I and II were controls and groups III and IV were cultured in the presence of 100 microM 4-HNE. Groups II and IV were pre-cultured in the media containing 10 microM BHT for 24 hrs which was designated as 0 time point. Lenses were withdrawn at 24 and 72 h and evaluated for opacification by digital image analysis. Induction of the specific GST isozyme (gammaGST8-8) was studied in the lens epithelium by immunohistochemical studies. Results. Digital image analysis revealed amelioration in opacification induced by 4-HNE, when the lenses were precultured with BHT. Immunohistochemical studies show that BHT induced GST8-8 several folds in the epithelium.. These studies indicate that pretreatment with BHT would increase the lens capacity to detoxify 4-HNE by conjugating it with GSH, thus assigning an important detoxication role to this specific GST isozyme in oxidative cataract.

Topics: Aldehydes; Animals; Antioxidants; Butylated Hydroxytoluene; Cataract; Enzyme Induction; Glutathione Transferase; Image Processing, Computer-Assisted; Immunohistochemistry; Inactivation, Metabolic; Isoenzymes; Lens, Crystalline; Lipid Peroxidation; Rats; Rats, Inbred Lew

Free radicals have extremely short half-lives and they readily oxidize lipids and initiate an autocatalytic chain reaction of lipid peroxidation, which leads to the formation of lipid peroxides. The lipid peroxides undergo degradation to form metastable lipid aldehydes such as 4-hydroxynonenal (HNE). We have shown earlier that under hyperglycemia, lipid peroxides increase; and aldose reductase, an enzyme that reduces glucose to sorbitol, efficiently reduces HNE. The purpose of the present studies was thus to investigate the role of HNE in hyperglycemic cataract and understand the mechanism(s) of its prevention by antioxidants and aldose reductase inhibitors. HNE and hyperglycemic cataract were developed by culturing rat lenses in TC-199 medium containing 50 microM HNE and 50 mM glucose, respectively. The effect of an anti-oxidant, trolox, and an aldose reductase inhibitor, sorbinil, on the progression of HNE and hyperglycemic cataract, evaluated by digital image analysis, was followed for 8 and 9 days, respectively. In lenses cultured with HNE, the decrease in transmitted light was 43, 65, and 87% on Days 3, 5, and 8, respectively. Trolox ameliorated the HNE cataract, whereas sorbinil accelerated the progression of HNE cataract and prevented the progression of hyperglycemic cataract. It is concluded that HNE formed under hyperglycemia may play a pivotal role in diabetic cataractogenesis.

Topics: Aldehyde Reductase; Aldehydes; Animals; Cataract; Chromans; Cross-Linking Reagents; Enzyme Inhibitors; Image Enhancement; Imidazoles; Imidazolidines; Rats

Age-related cataractogenesis is a significant health problem worldwide. Oxidative stress has been suggested to be a common underlying mechanism of cataractogenesis, and augmentation of the antioxidant defenses of the ocular lens has been shown to prevent or delay cataractogenesis. The present studies were designed to test the efficacy of curcumin, an antioxidant present in the commonly used spice turmeric, in preventing cataractogenesis in an in vitro rat model. Rats were maintained on an AIN-76 diet (ICN Pharmaceuticals Inc, Cleveland) for 2 wk, after which they were given a daily dose of corn oil alone or 75 mg curcumin/kg in corn oil for 14 d. Their lenses were removed and cultured for 72 h in vitro in the presence or absence of 100 mumol 4-hydroxy-2-nonenal (4-HNE)/L, a highly electrophilic product of lipid peroxidation. The results of these studies showed that 4-HNE caused opacifications of cultured lenses as indicated by the measurements of transmitted light intensity using digital image analysis. However, the lenses from curcumin-treated rats were much more resistant to 4-HNE-induced opacification than were lenses from control animals. Curcumin treatment caused a significant induction of the glutathione S-transferase (GST) isozyme rGST8-8 in rat lens epithelium. Because rGST8-8 utilizes 4-HNE as a preferred substrate, we suggest that the protective effect of curcumin may be mediated through the induction of this GST isozyme. These studies suggest that curcumin may be an effective protective agent against cataractogenesis induced by lipid peroxidation.

Topics: Aldehydes; Animals; Antioxidants; Cataract; Curcumin; Disease Models, Animal; Epithelium; Glutathione Transferase; Immunohistochemistry; Lens, Crystalline; Lipid Peroxidation; Organ Culture Techniques; Oxidative Stress; Random Allocation; Rats