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Fan X, Monnier VM. Protein posttranslational modification (PTM) by glycation: Role in lens aging and age-related cataractogenesis. Exp Eye Res 2021; 210:108705. [PMID: 34297945 DOI: 10.1016/j.exer.2021.108705] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/09/2021] [Accepted: 07/17/2021] [Indexed: 01/11/2023]
Abstract
Crystallins, the most prevalent lens proteins, have no turnover throughout the entire human lifespan. These long-lived proteins are susceptible to post-synthetic modifications, including oxidation and glycation, which are believed to be some of the primary mechanisms for age-related cataractogenesis. Thanks to high glutathione (GSH) and ascorbic acid (ASA) levels as well as low oxygen content, the human lens is able to maintain its transparency for several decades. Aging accumulates substantial changes in the human lens, including a decreased glutathione concentration, increased reactive oxygen species (ROS) formation, impaired antioxidative defense capacity, and increased redox-active metal ions, which induce glucose and ascorbic acid degradation and protein glycation. The glycated lens crystallins are either prone to UVA mediated free radical production or they attract metal ion binding, which can trigger additional protein oxidation and modification. This vicious cycle is expected to be exacerbated with older age or diabetic conditions. ASA serves as an antioxidant in the human lens under reducing conditions to protect the human lens from damage, but ASA converts to the pro-oxidative role and causes lens protein damage by ascorbylation in high oxidation or enriched redox-active metal ion conditions. This review is dedicated in honor of Dr. Frank Giblin, a great friend and superb scientist, whose pioneering and relentless work over the past 45 years has provided critical insight into lens redox regulation and glutathione homeostasis during aging and cataractogenesis.
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Affiliation(s)
- Xingjun Fan
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.
| | - Vincent M Monnier
- Department of Pathology, United States; Biochemistry, Case Western Reserve University, Cleveland, OH, United States
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Ávila F, Ravello N, Zanocco AL, Gamon LF, Davies MJ, Silva E. 3-Hydroxykynurenine bound to eye lens proteins induces oxidative modifications in crystalline proteins through a type I photosensitizing mechanism. Free Radic Biol Med 2019; 141:103-114. [PMID: 31128239 DOI: 10.1016/j.freeradbiomed.2019.05.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/19/2019] [Accepted: 05/21/2019] [Indexed: 12/27/2022]
Abstract
Photosensitized reactions mediated by endogenous chromophores have been associated with the etiology of age-related cataract disease. Endogenous chromophores such as 3-hydroxykynurenine (3OHKN) can be found in both free form, and bound to crystallin proteins. However, their efficiency in generating photo-induced oxidative modifications on eye lens proteins is not completely understood. In this work, the efficiency and photodynamic activity of 3OHKN bound to both lysine (3OHKN-Lys) and bovine lens proteins (3OHKN-BLP) was assessed and compared with the photosensitizing activity of the major chromophore arising from glucose degradation (GDC). The photosensitizing activity of 3OHKN-Lys, 3OHKN-BLP and GDC was characterized by measurement of singlet oxygen quantum yields, O2 consumption, SDS-PAGE and amino acid analysis of the photo-oxidized proteins. Singlet oxygen quantum yields under 20% O2 atmosphere were 0.02, 0.01, and 0.27 for 3OHKN-Lys, 3OHKN-BLP and GDC, respectively. O2 consumption by photosensitized reactions was more efficient for 3OHKN-BLP, with the extent of O2 consumption being ∼28% higher than for 3OHKN-Lys and GDC under both 5 and 20% O2. SDS-PAGE showed that protein crosslinking is dependent on the O2 concentration, and more extensive at 5 than 20% O2. GDC and 3OHKN-Lys were the most efficient crosslinkers at 20 and 5% O2, respectively. Amino acid analysis of the irradiated proteins showed consumption of Trp, His, Tyr and Phe, and formation of kynurenine (from Trp), methionine sulfoxide (from Met) and DOPA (from Tyr). Kynurenine formation was dependent on the O2 concentration with higher amounts detected at 5 than 20% O2 for 3OHKN-BLP and 3OHKN-Lys, with 3OHKN-BLP the most efficient sensitizer. Our results suggest that 3OHKN-BLP can elicit photo-oxidative damage mainly by a type I photosensitizing mechanism, with this likely to be the most prevalent pathway at the low physiologic O2 concentrations in the eye lens.
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Affiliation(s)
- Felipe Ávila
- Escuela de Nutrición y Dietética, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Interdisciplinary Center on Aging, Universidad de Talca, Talca, Chile.
| | - Natalia Ravello
- Escuela de Nutrición y Dietética, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile; Interdisciplinary Center on Aging, Universidad de Talca, Talca, Chile
| | - Antonio L Zanocco
- Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Luke F Gamon
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Eduardo Silva
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile
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Ramalho JS, Marques C, Pereira PC, Mota MC. Role of Glycation in Human Lens Protein Structure Change. Eur J Ophthalmol 2018; 6:155-61. [PMID: 8823589 DOI: 10.1177/112067219600600211] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE Protein glycation may be involved in cataract development, by altering protein structure, particularly amino acid composition, and formation of fluorophores through a Maillard reaction. This study was designed to evaluate major changes in early and advanced (fluorescent) glycation products, with special emphasis on glycation-induced changes in amino acid composition of lens proteins. METHODS We analyzed 50 human cataractous lenses (25 diabetic and 25 non-diabetic). Glycated proteins were isolated by affinity chromatography. Glycated and non-glycated proteins were separated by molecular sieve chromatography and further analyzed by RP-HPLC to establish the amino acid content. Early glycation levels were determined as furosine content and advanced glycation products were quantified by the characteristic fluorescence. RESULTS Specific lens fractions (HMW and LMW) present significant differences in fluorescence levels between glycated and non-glycated proteins, specially in cataractous lenses from diabetic patients in which all proteins analyzed presented higher glycation levels than in non-diabetic patients. The amino and analysis of glycated proteins also revealed some important differences in specific basic residues (namely Lys, Arg and His) compared to the non-glycated fraction. CONCLUSIONS The results suggest that protein glycation may be involved in changes in amino acid composition and fluorophore formation. This process may well account for the increased risk factor that diabetes represents for cataract development.
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Affiliation(s)
- J S Ramalho
- Department of Ophthalmology and Visual Sciences, University of Coimbra, Portugal
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Birlouez-Aragon I, Tessier F, Mompeyssin V, Baciuska J. Lack of effect of copper on advanced Maillard reaction and glucose autoxidation at physiological concentrations of albumin. Redox Rep 2016; 2:127-32. [DOI: 10.1080/13510002.1996.11747039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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5
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Avila F, Friguet B, Silva E. Photosensitizing Activity of Endogenous Eye Lens Chromophores: An Attempt to Unravel Their Contributions to Photo-Aging and Cataract Disease. Photochem Photobiol 2015; 91:767-79. [DOI: 10.1111/php.12443] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/20/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Felipe Avila
- Escuela de Nutrición y Dietética; Facultad de Ciencias de la Salud; Universidad de Talca; Talca Chile
- Programa de Investigación de Excelencia Interdisciplinario en Envejecimiento Saludable (PIEI-ES); Universidad de Talca; Talca Chile
| | - Bertrand Friguet
- UPMC Univ. Paris 06; CNRS UMR 8256; INSERM U1164; Adaptation Biologique et Vieillissement; Institute of Biology Paris-Seine; Paris France
| | - Eduardo Silva
- Departamento de Química Física; Facultad de Química; Pontifícia Universidad Católica de Chile; Santiago Chile
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Burd J, Lum S, Cahn F, Ignotz K. Simultaneous noninvasive clinical measurement of lens autofluorescence and rayleigh scattering using a fluorescence biomicroscope. J Diabetes Sci Technol 2012; 6:1251-9. [PMID: 23294769 PMCID: PMC3570864 DOI: 10.1177/193229681200600603] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Lens autofluorescence increases with the age of the subject, and the fluorophores responsible are associated with cataract, retinopathy, and other complications of diabetes. We built a scanning confocal lens fluorescence biomicroscope suitable for routine clinical measurement of lens autofluorescence and light scattering and report data from 127 healthy subjects. METHOD The fluorescence biomicroscope focuses a beam of light from a blue light-emitting diode on the lens and measures fluorescent green light and blue scattered light using a sensitive silicon photomultiplier. The system includes a target fixation light and a video camera for alignment and automatic pupil tracking. Under software control, a volume of measurement is scanned from behind the posterior lens capsule, through the lens to the aqueous humor, and then back again. Software computes the average ratio of lens autofluorescence to scattered light in the central portion of the lens. Self-reported healthy nondiabetic subjects were examined by an optometrist; if their eyes were healthy and without significant cataract, they were entered into the study. RESULTS Valid lens autofluorescence data were collected from 127 subjects between 21 and 70 years of age. A linear model for lens autofluorescence intensity with age was highly statistically significant, and the improvement in fit for higher-order polynomial models was not statistically significant. The ratio of lens autofluorescence to light scatter was also calculated; regression analysis showed significant curvature for the relationship of the fluorescence ratio to age, so a nonlinear model was used to estimate the mean ratio of autofluorescence to scatter and its prediction intervals as a function of age. CONCLUSIONS Our observation of a strongly significant linear regression of fluorescence intensity with age of the subjects agrees with the results from previous studies, as does a nonlinear model for the fluorescence ratio. The fluorescence biomicroscope enables the clinician to identify patients with fluorescence ratio significantly higher than expected for their age.
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Affiliation(s)
- John Burd
- Freedom Meditech, San Diego, California
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7
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The pathogenic role of Maillard reaction in the aging eye. Amino Acids 2010; 42:1205-20. [DOI: 10.1007/s00726-010-0778-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 08/25/2010] [Indexed: 12/31/2022]
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8
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Flesner P, Sander B, Henning V, Parving HH, Dornonville de la Cour M, Lund-Andersen H. Cataract surgery on diabetic patients. A prospective evaluation of risk factors and complications. ACTA OPHTHALMOLOGICA SCANDINAVICA 2002; 80:19-24. [PMID: 11906299 DOI: 10.1034/j.1600-0420.2002.800105.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE This study presents an evaluation of cataract surgery on diabetic patients. One experienced surgeon carried out phaco emulsification on all subjects and the same surface-coated one-piece PMMA-lens-type was implanted. The lens fluorescence and the blood-aqueous barrier (BAB) were then evaluated as experimental preoperative risk indicators. RESULTS During follow-up, 10 out of 39 diabetic patients progressed unilaterally in diabetic retinopathy or developed macular oedema, a significant relative risk. Neither lens fluorescence, BAB, HbA1c, level of retinopathy, type/duration of diabetes, diabetes treatment or antihypertensive treatment differed significantly between the group of patients with postoperative progression of retinopathy/macular oedema and those without. Results indicated NIDDM (non-insulin-dependent diabetes mellitus/type 2 diabetes) patients might have increased risk of a postoperative macular oedema. CONCLUSION When diabetic retinopathy (DR) is not in a proliferative phase it should not be regarded as a contraindication to modern cataract surgery. Neither lens fluorescence nor BAB is valuable as a risk indicator for postoperative progression of DR.
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Affiliation(s)
- Per Flesner
- Department of Ophthalmology, Herlev University Hospital, Copenhagen, Denmark.
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Golej J, Hoeger H, Radner W, Unfried G, Lubec G. Oral administration of methylglyoxal leads to kidney collagen accumulation in the mouse. Life Sci 1998; 63:801-7. [PMID: 9740317 DOI: 10.1016/s0024-3205(98)00336-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Methylglyoxal (MG) is a physiological substrate of the glyoxalase system which is impaired in the diabetic state and implicated in the development of diabetic complications. Like other reactive aldehydes in diabetes mellitus (DM) this carbonyl can bind to and modify proteins which may lead to changes of biochemical and biophysical properties of connective tissue proteins, a hallmark of diabetes mellitus. As previous studies on MG effects were confounded by other aldehydes found in DM, we decided to administer MG to 10 healthy, female OF-1 mice for a period of five months, at a level of 50 mg/kg body weight per day using 10 healthy untreated litter mates as controls. The left kidneys were taken for the determination of total kidney collagen, fluorescence, acid solubility of collagen and the right kidneys were used for the determination of glomerular basement membrane thickness. Total kidney collagen was significantly higher in the MG treated mice compared to control mice. Only about half the amount of collagen could be extracted from kidneys of MG treated animals indicating reduced solubility. Fluorescence in proteins from extracted kidneys of MG treated animals was about twice that of untreated animals. Glomerular basement membrane thickness was significantly higher in MG treated animals. Our findings indicate that MG can increase glomerular basement membrane thickness and the suggested underlying mechanism may be decreased solubility by increased cross linking as reflected by elevated protein fluorescence and decreased acid salt extraction. The involvement of MG in the development of diabetic complications postulated by others is herewith clearly supported by our findings.
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Affiliation(s)
- J Golej
- University of Vienna, Department of Pediatrics, Austria
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11
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Hook DW, Harding JJ. Inactivation of glyceraldehyde 3-phosphate dehydrogenase by sugars, prednisolone-21-hemisuccinate, cyanate and other small molecules. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1362:232-42. [PMID: 9540854 DOI: 10.1016/s0925-4439(97)00084-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Diabetes, diarrhoea, renal failure and glucocorticoid therapy have all been identified as independent risk factors for cataract. Increased post-translational modification of proteins, leading to inactivation of enzymes and induction of conformational changes within proteins could result in lens opacification and cataract. Aspirin has been associated with many beneficial effects, including protection against cataract, in-vivo. alpha-Crystallin has been shown to act as a molecular chaperone in-vitro. This lenticular protein prevented the thermal aggregation of other lens proteins in-vitro and has sequence and functional homology with the small heat shock proteins. Glyceraldehyde 3-phosphate dehydrogenase (GAP-DH) is constitutively expressed in tissues and is susceptible to chemical modification in-vivo. In-vitro incubations of GAP-DH with sugars, cyanate and prednisolone-21-hemisuccinate, all led to significant loss of enzyme activity with time in two buffer systems. Rapid inactivation occurred when GAP-DH was incubated with fructose 6-phosphate or prednisolone-21-hemisuccinate. Slower inactivation was observed when GAP-DH was incubated with fructose, glucose 6-phosphate or potassium cyanate. Glucose did not inactivate GAP-DH under the conditions of our experiments. Aspirin and ibuprofen were shown to inactivate GAP-DH very rapidly in-vitro. Bovine lenticular alpha-crystallin conferred no protection against GAP-DH inactivation. This is the first occasion that alpha-crystallin has been demonstrated to be unable to protect against inactivation in our chemical enzyme inactivation system. This may have implications for the susceptibility of lenticular GAP-DH to post-translational inactivation.
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Affiliation(s)
- D W Hook
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
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12
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Lin SY, Lee SM, Li MJ, Liang RC. Fourier transform infrared spectral evidences for protein conformational changes in immature cataractous human lens capsules accelerated by myopia and/or systemic hypertension. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 1997; 53A:1507-1513. [PMID: 9255966 DOI: 10.1016/s1386-1425(97)00077-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The possible changes in protein structures of the cataractous human lens capsules of the immature patients with myopia and/or systemic hypertension have been investigated using Fourier transform infrared (FT-IR) microspectroscopy. Second-derivative and deconvolution methods have been applied to obtain the position of the overlapping components of the amide I band and assign them to different secondary structures. Changes in the protein secondary structure and composition of amide I band were estimated quantitatively from Fourier self-deconvolution and curve fitting algorithms. The results indicate that myopia and/or systemic hypertension were found to significantly modify the protein secondary structure of the cataractous human lens capsules to increase the beta-type structure and random coil and decrease the alpha-helix structure. Myopia-induced conformational change in triple helix structure was more pronounced. In conclusion, myopia and/or systemic hypertension seem to modify the conformation of the protein structures in cataractous human lens capsule to change ionic permeation through lens capsule to accelerate the cataract formation of senile patients.
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Affiliation(s)
- S Y Lin
- Department of Medical Research and Education, Veterans General Hospital-Taipei, People's Republic of China
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Shoda H, Miyata S, Liu BF, Yamada H, Ohara T, Suzuki K, Oimomi M, Kasuga M. Inhibitory effects of tenilsetam on the Maillard reaction. Endocrinology 1997; 138:1886-92. [PMID: 9112383 DOI: 10.1210/endo.138.5.5151] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It has been hypothesized that advanced Maillard reaction in vivo could explain some of the age- and diabetes-related changes. Furthermore, involvement of the Maillard reaction with Alzheimer's disease has also been suggested, as advanced glycation end products, such as pyrraline and pentosidine, were demonstrated to localize in lesions of the disease. Although aminoguanidine has been studied extensively and established as an inhibitor of the Maillard reaction, other candidates have not been investigated thoroughly. In the present study, we examined the inhibitory effect of tenilsetam [(+/-)-3-(2-thienyl)-2-piperazinone], an antidementia drug, on the Maillard reaction. Tenilsetam inhibited glucose- and fructose-induced polymerization of lysozyme in a concentration-dependent manner in vitro. Reduced enzymatic digestibility of collagen incubated with 100 mM glucose for 4 weeks was also restored to a control level by coincubation with 100 mM tenilsetam. To determine whether tenilsetam inhibits the Maillard reaction in vivo, streptozotocin-induced diabetic rats were treated with tenilsetam (50 mg/kg x day). Elevated levels of advanced glycation end-product-derived fluorescence and pyrraline in renal cortex and aorta of diabetic rats were suppressed by the administration of tenilsetam for 16 weeks. These inhibitory effects of this agent on advanced glycation in diabetic rats suggested its potential therapeutic role in controlling diabetic complications.
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Affiliation(s)
- H Shoda
- Second Department of Internal Medicine, Kobe University School of Medicine, Chuo-ku, Japan
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Ortwerth BJ, Prabhakaram M, Nagaraj RH, Linetsky M. The relative UV sensitizer activity of purified advanced glycation endproducts. Photochem Photobiol 1997; 65:666-72. [PMID: 9114742 DOI: 10.1111/j.1751-1097.1997.tb01909.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The oxidation products of ascorbic acid react with lens proteins to form advanced glycation endproducts (AGE) that are capable of generating reactive oxygen species when irradiated with UVA light. L-Threose, the most active of these oxidation products, was reacted with N-acetyl lysine and six AGE peaks were isolated by RP-HPLC. Each peak exhibited fluorescence and generated superoxide anion and singlet oxygen in response to UV light. Solutions of these AGE peaks (50 micrograms/mL) generated 5-10 nmol/mL of superoxide anion during a 30 min irradiation. This activity was 100-fold less than the superoxide anion generated by kynurenic acid and 400-fold less than riboflavin. Ultraviolet irradiation generated from 1.2 to 2.7 mumol/mL of singlet oxygen with the purified threose AGE compounds. This activity was similar to that seen with other purified AGE compounds (pentosidine, LM-1 and Ac-FTP) and with kynurenine and 3-OH kynurenine. This considerable singlet oxygen formation, however, was still 40-fold less than that obtained with kynurenic acid and 100-fold less than riboflavin under the same irradiation conditions. In spite of this lower sensitizer efficiency, the purified AGE generated 20-60-fold more singlet oxygen on a weight basis than either crude ascorbic acid glycated proteins or a preparation of water-insoluble proteins from aged normal human lenses. On a molar basis, therefore, AGE could account for the sensitizer activity in these protein preparations if they represented less than 1% of the total amino acids.
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Affiliation(s)
- B J Ortwerth
- Mason Eye Institute, University of Missouri, Columbia 65212, USA.
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15
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Nakamura K, Nakazawa Y, Ienaga K. Acid-stable fluorescent advanced glycation end products: vesperlysines A, B, and C are formed as crosslinked products in the Maillard reaction between lysine or proteins with glucose. Biochem Biophys Res Commun 1997; 232:227-30. [PMID: 9125137 DOI: 10.1006/bbrc.1997.6262] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Vesperlysines A and B, 6-hydroxy-1,4-di{6-(L-norleucyl)}-1H-pyrrolo[3,2-b]pyridinium and its 5-methyl derivative, respectively, and Vesperlysine C, 5-hydroxy-methyl-1,6-di{6-(L-norleucyl)}-1H-pyrrolo[3,4-b] pyridinium, are isolated as major fluorescent advanced glycation end products (AGEs) from hydrochloric acid hydrolysis of AGE-BSA, bovine serum albumin (BSA) modified by the Maillard reaction with glucose. These fluorophores are glycation products and not artifacts of hydrolysis, since they are also detected in the reaction mixture of lysine and glucose prior to hydrolysis. Vesperlysines are crosslinked products from two lysine side-chains in proteins and are considered to be generated from lysines and the oxidative degradation of glucose, because the six carbon skeleton of glucose in its original form was not incorporated into each structure. These compounds are most likely glycoxidation products like pentosidine. This reasoning is supported by the formation of the same compounds in the Maillard reactions in which ascorbic acid or other sugars with shorter carbon chains are used.
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Affiliation(s)
- K Nakamura
- Institute of Bio-Active Science, Nippon Zoki Pharmaceutical Co. Ltd., Hyogo, Japan
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16
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Marques C, Ramalho JS, Pereira P, Mota MC. Bendazac decreases in vitro glycation of human lens crystallins. Decrease of in vitro protein glycation by bendazac. Doc Ophthalmol 1995; 90:395-404. [PMID: 8620822 DOI: 10.1007/bf01268125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bendazac has been used as an anti-cataractogenic drug. It has been reported that this acts by preventing protein denaturation. In this study the ability of bendazac to inhibit in vitro glycation of human lens crystallins was evaluated. Possible effects of bendazac were detected by incubation of WS crystallins with the reducing sugars glucose and fructose. The efficiency of bendazac was evaluated by means of selected parameters including: browning, glycation (measured as tyrosine content) and specific NTP-fluorescence. The results showed clearly that bendazac (bendazac L-lysine and sodium) inhibits the early stages of protein glycation, as well as the formation of fluorescent advanced glycation products. Bendazac lysine (20 mM) proved to be more effective in inhibiting fluorescence development (67% inhibition) that the corresponding sodium salt (35% inhibition). No significant differences were found with respect to furosine levels; about 40% inhibition was produced with either bendazac lysine or sodium salt bendazac clearly inhibits glycation of human lens crystallins, as can be efficiently monitored by following specific changes in lens protein fluorescence. These results may constitute a new and relevant therapeutic approach to monitoring cataract development.
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Affiliation(s)
- C Marques
- Department of Ophthalmology and Visual Sciences, Biomedical Institute for Research in Light and Image, Celas, Coimbra, Portugal
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17
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Mota MC, Carvalho P, Ramalho JS, Cardoso E, Gaspar AM, Abreu G. Protein glycation and in vivo distribution of human lens fluorescence. Int Ophthalmol 1995; 18:187-93. [PMID: 7797380 DOI: 10.1007/bf00951795] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glycated proteins formed by the Maillard reaction were measured by furosine determination in human normal lenses and in senile and diabetic cataracts. Furosine, an hydrolysis product of fructose-lysine adduct formed in the early stages of the Maillard reaction, was measured by high performance liquid chromatography (HPLC). Furosine levels in diabetic cataracts were found to be 3 to 4 times higher than those observed for senile cataracts. The increased glycation levels both in cortex and nucleus were related to the increase of fluorescence determined in vitro by fluorometry and in vivo by Scheimpflug photography. Lens proteins were incubated with glucose and it has been demonstrated that protein glycation occurred parallel with the increase in concentration of fluorescent chromophores that present similar characteristics as those observed in vivo. The results indicate that protein insolubilization seemed to involve preferentially glycated proteins and at least in diabetic cataracts, the process seems to be initiated in the cortical region.
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Affiliation(s)
- M C Mota
- Center for Ophthalmology, University of Coimbra, Portugal
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18
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Suárez G, Oronsky A, Koch M. Age-dependent structural changes in intact human lenses detected by synchrotron radiation X-ray scattering. Correlation with Maillard reaction protein fluorescence. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(17)46763-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Abstract
This paper reviews the changes which occur in the human lens in diabetes. They include refractive changes and cataract and age-related increases in thickness, curvatures, light scattering, autofluorescence and yellowing. The incidence of cataract is greatly increased over the age of 50 years, slightly more so in women, compared with non-diabetics. Experimental models of sugar cataract provide some evidence for the mechanism of the uncommon, but morphologically distinct, juvenile form of human diabetic cataract, where an osmotic mechanism due to sugar alcohol accumulation has been thoroughly studied in diabetic or galactose-fed rats. The discrepancy between the ready accumulation of sugar alcohol in the lens in model systems and the very slow kinetics of aldose reductase (AR) has not been satisfactorily explained and suggests that the mechanism of polyol formation is not yet fully understood in mammalian systems. The activity of AR in the human lens lies mainly in the epithelium and there appears to be a marginal expectation that sufficient sorbitol accumulates in cortical lens fibres to explain the lens swelling and cataract on an osmotic basis. This is even more so in the cataracts of adult diabetics, which resemble those of age-related non-diabetic cataracts in appearance. The very low levels of sorbitol in adult diabetic lenses make an osmotic mechanism for the increased risk of cataract even less likely. Other mechanisms, including glycation and oxidative stress, are discussed. The occurrence of cataract is a predictor for increased mortality in the diabetic.
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Affiliation(s)
- A J Bron
- Department of Ophthalmology, University of Oxford, UK
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20
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Harding JJ, Egerton M, van Heyningen R, Harding RS. Diabetes, glaucoma, sex, and cataract: analysis of combined data from two case control studies. Br J Ophthalmol 1993; 77:2-6. [PMID: 8435392 PMCID: PMC504412 DOI: 10.1136/bjo.77.1.2] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Data from two case control studies in Oxfordshire were combined and analysed. The combined study covered 1940 subjects, 723 cases, and 1217 controls, between the ages of 50 and 79 with a response rate of 97% for cases and 94% for controls. Diabetes was shown to be a powerful and highly significant risk factor for cataract with a relative risk of 5.04. More than 11% of cataracts in Oxfordshire are attributable to diabetes. The relative risk did not increase significantly with age within the range 50 to 79 years but was higher in females than in males. For females with diabetes the relative risk was 7.85 with 95% confidence interval from 4.30 to 14.3 compared with 3.42 with confidence interval from 2.05 to 5.71 for males with diabetes. Diabetes remained a powerful risk factor when other identified risk factors had been controlled for. No known mechanism for the development of diabetic complications provides an explanation for the excess risk in females. Combination of the two studies led to better estimates of the relative risk of glaucoma as a risk factor for cataract (3.96 with 95% confidence interval from 2.35 to 6.68). The relative risk appeared to be greater in women than in men but this difference was not statistically significant. There was no significant change in risk with age. Glaucoma is a powerful and independent risk factor for cataract in both sexes and may be responsible for 5% of all cataracts in our area.
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Affiliation(s)
- J J Harding
- Nuffield Laboratory of Ophthalmology, University of Oxford
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21
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Ortwerth BJ, Slight SH, Prabhakaram M, Sun Y, Smith JB. Site-specific glycation of lens crystallins by ascorbic acid. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1117:207-15. [PMID: 1525182 DOI: 10.1016/0304-4165(92)90081-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The oxidation of ascorbic acid leads to the formation of several compounds which are capable of reacting with protein amino groups via a Maillard reaction. Radioactivity from [1-14C]ascorbic acid was linearly incorporated into lens crystallins over a 10 day period in the presence of NaCNBH3. This rate of incorporation was 6-7-fold more rapid than that obtained with [14C]glucose under the same conditions. SDS-PAGE showed a linear incorporation into all the crystallin subunits. [1-14C]Ascorbic acid-label led alpha-crystallin was separated into its component A and B subunits, and each was digested with chymotrypsin. HPLC peptide analysis showed a differential labelling of the various lysine residues. Analysis of the peptides by mass spectrometry allowed the identification of the sites and the extent of modification. These values ranged from 6% for Lys-78 to 36% for Lys-11 in the A subunit and from 5% for Lys-82 to an average of 38% for the peptide containing Lys-166, Lys-174 and Lys-175 in the B subunit. Amino acid analysis demonstrated a single modification reaction producing N epsilon-(carboxymethyl)lysine. This agreed with the mass increase of 58 observed for each modified peptide.
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Affiliation(s)
- B J Ortwerth
- Mason Institute of Ophthalmology, University of Missouri, Columbia 65212
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22
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Knecht KJ, Feather MS, Baynes JW. Detection of 3-deoxyfructose and 3-deoxyglucosone in human urine and plasma: evidence for intermediate stages of the Maillard reaction in vivo. Arch Biochem Biophys 1992; 294:130-7. [PMID: 1550339 DOI: 10.1016/0003-9861(92)90146-n] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
3-Deoxyglucose (3-deoxy-D-erythro-hexos-2-ulose) (3-DG) is a reactive dicarbonyl intermediate involved in the polymerization and browning of proteins by glucose in vitro. Damage to protein by formation of 3-DG in vivo is thought to be limited by enzymes which convert 3-DG to less reactive species, such as 3-deoxyfructose (3-DF). We have developed a sensitive and specific assay for measuring 3-DG and 3-DF in human urine and plasma. In this assay, 3-DG and 3-DF are reduced to 3-deoxy-hexitols (3-DH), using either NaBH4 or NaBD4, and then analyzed by selected ion monitoring gas chromatography-mass spectrometry. Based on comparative analysis of samples reduced with NaBD4 versus NaBD4, 3-DH in urine was derived exclusively (greater than 99%) from 3-DF, while 3-DG accounted for approximately 15% of 3-DH in plasma. The concentrations of 3-DH in fasting human urine and plasma were 5.3 +/- 1.5 micrograms/mg creatinine (n = 18) and 7.2 +/- 1.7 micrograms/dl (n = 18), respectively. The concentrations of 3-DG and 3-DF in plasma (n = 7) were 1.0 +/- 0.2 and 6.7 +/- 1.6 micrograms/dl, respectively. These results suggest that several milligrams of 3-DG are formed in the body per day and detoxified by reduction to 3-DF and support the role of 3-DG as an intermediate in the browning of protein via the Maillard reaction in vivo.
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Affiliation(s)
- K J Knecht
- Department of Chemistry, University of South Carolina, Columbia 29208
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23
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Miyata S, Monnier V. Immunohistochemical detection of advanced glycosylation end products in diabetic tissues using monoclonal antibody to pyrraline. J Clin Invest 1992; 89:1102-12. [PMID: 1556177 PMCID: PMC442966 DOI: 10.1172/jci115690] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pyrraline is one of the major Maillard compounds resulting from the reaction of glucose with amino compounds at slightly acidic pH. For in vivo studies, monoclonal pyrraline antibodies were raised after immunization of Balb/c mice with keyhole limpet hemocyamin-caproyl pyrraline conjugate. Of 660 hybridoma clones from one donor, 260 produced an antibody to the free hapten, two of which named Pyr-A and Pyr-B also cross-reacted with L-lysyl pyrraline. Using Pyr-B antibody and an ELISA, a gradual increase in pyrraline immunoreactivity was observed in serum albumin incubated with glucose or 3-deoxyglucosone. Plasma pyrraline levels increased fourfold (P less than 0.001) in Sprague-Dawley rats upon induction of diabetes with streptozotocin and were twofold increased in randomly selected plasmas from diabetic humans. Highly specific pyrraline immunoreactivity was detected in sclerosed glomeruli from diabetic and old normal kidneys as well as in renal arteries with arteriolosclerosis and in perivascular and peritubular sclerosed extracellular matrix and basement membranes. The preferential localization of pyrraline immunoreactivity in the extracellular matrix strengthens the notion that the advanced glycosylation reaction may contribute to decreased turnover and thickening of the extracellular matrix in diabetes and aging.
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Affiliation(s)
- S Miyata
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
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24
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Nagaraj RH, Monnier VM. Isolation and characterization of a blue fluorophore from human eye lens crystallins: in vitro formation from Maillard reaction with ascorbate and ribose. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1116:34-42. [PMID: 1540622 DOI: 10.1016/0304-4165(92)90125-e] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A blue fluorophore, named LM-1 was isolated from human eye lens crystallins. The fluorescence property of LM-1 (excitation/emission, 366/440 nm) is similar to the fluorescence originating during non-enzymatic glycation (Maillard reaction) of proteins with the reducing sugars. LM-1 accumulates linearly with age in highly cross-linked water insoluble crystallins and is present at higher levels in cataractous lenses. The fluorophore could be synthesized by incubation of bovine serum albumin (BSA) with ribose, but not with glucose or fructose. Incubation of bovine lens crystallins with ascorbic acid (ASA) and its oxidative products, dehydroascorbic acid (DHA) and 2,3-diketogulonic acid (DKG) in presence of oxygen resulted in LM-1 formation. When oxygen was removed from the system, only DHA and DKG could synthesize LM-1, but not ASA, suggesting that ASA oxidation is obligatory for LM-1 synthesis. Modification of lysine residues on BSA prior to incubation with ribose resulted in corresponding decrease in LM-1 formation. Since ASA concentration is unusually high in lens and has been found to be a powerful glycating agent of crystallins and since LM-1 does not form with hexoses, it is likely that ASA is the major precursor of LM-1.
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Affiliation(s)
- R H Nagaraj
- Institute of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106
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25
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Taniguchi N. Clinical significances of superoxide dismutases: changes in aging, diabetes, ischemia, and cancer. Adv Clin Chem 1992; 29:1-59. [PMID: 1585847 DOI: 10.1016/s0065-2423(08)60221-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- N Taniguchi
- Department of Biochemistry, Osaka University Medical School, Japan
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26
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Wolff SP. Is hyperglycemia risky enough to justify the increased risk of hypoglycemia linked with tight diabetes control? BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1991; 46:129-39. [PMID: 1782005 DOI: 10.1016/0885-4505(91)90060-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There is an ongoing debate about the possible disadvantages of human insulin use with respect to a possibly lower awareness of hypoglycemia than is associated with animal insulin usage. Participants in this debate have not, however, discussed a major contributory factor to this life-threatening acute complication of diabetes, the pressure on patients to achieve normal levels of blood glucose. This pressure stems from the view that hyperglycemia is the major causative factor in the long-term diabetic complications. However, the evidence that supranormal levels of tissue and plasma glucose contribute to the diabetic tissue damage is not as strong as the arguments on behalf of this position. Indeed, elevated glycemia may be no more than a crude index of other, unknown metabolic derangements which may be causative agents in diabetes-associated tissue damage. Intensive efforts to "normalize" glycemia lack experimental and clinical justification, distract attention from other possible mechanisms, and may impose an unnecessary risk on the insulin-dependent diabetic population since intensive "normalization" of glycemia lowers hypoglycemia awareness, and thus increases risk of hypoglycemia, irrespective of the type of insulin used.
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Affiliation(s)
- S P Wolff
- Department of Clinical Pharmacology, University College and Middlesex School of Medicine, London, England
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27
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Prabhakaram M, Ortwerth BJ. The glycation-associated crosslinking of lens proteins by ascorbic acid is not mediated by oxygen free radicals. Exp Eye Res 1991; 53:261-8. [PMID: 1915682 DOI: 10.1016/0014-4835(91)90082-p] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The reaction by which ascorbic acid (ASA) causes the glycation and crosslinking of lens proteins displays a rigid requirement for the presence of oxygen, and is inhibited by the presence of glutathione. Oxygen is required to oxidize ASA to dehydroascorbic acid (DHA) and other products which are the active glycating species. No evidence could be found to support a role for oxidative protein crosslinking by a free radical mechanism. Crosslinking was not inhibited by blocking protein sulfhydryl groups with iodoacetamide, nor were the protein crosslinks dissociated by boiling with 2% mercaptoethanol prior to SDS-PAGE. The addition of a variety of oxygen free radical quenchers had no effect on the extent of protein crosslinking. In fact, the removal of oxygen from the reaction mixture had no effect on either protein glycation, protein crosslinking or the modification of lysine residues, provided DHA was used as the glycating agent. All of these activities were inhibited, however, if ASA was the glycating agent. This confirms that oxygen is required only to convert ASA to DHA.
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Affiliation(s)
- M Prabhakaram
- Mason Institute of Opthalmology, University of Missouri, Columbia 65212
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28
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Abstract
The accumulation of the products of the Maillard reaction leads to structural and functional modifications of tissue proteins. In normoglycaemia, these modifications result in slow age-related accumulation of AGE-proteins. Hyperglycaemia accelerates formation of the Maillard products. The increased rate of Amadori products formation in poorly controlled diabetes leads to the impairment of the function of susceptible short-lived proteins and accelerates the formation of AGE on proteins with a long half-life. AGE accumulation increases protein crosslinking and leads to changes in the mechanical and biological properties of the affected proteins. AGE-modified proteins covalently bind other molecules. This may contribute to the formation of pathological tissue deposits and to the in situ formation of immune complexes. AGE-modified proteins also induce changes in biosynthetic/secretory patterns of macrophages, endothelial cells, and mesangial cells. These data led to the formulation of hypotheses which propose a central role for the Maillard products both in the process of ageing and in the development of the late complications of diabetes. More clinical studies are required to further substantiate these attractive hypotheses.
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Affiliation(s)
- M H Dominiczak
- Department of Pathological Biochemistry, Western Infirmary, Glasgow, UK
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29
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Abstract
To investigate the possible role of glycation in the onset of diabetic cataract we used calf lens crystallins as a model. After incubation with reducing sugars, the proteins were investigated by high-pressure gel permeation chromatography, SDS-PAGE and analytical ultracentrifugation. Glucose-6-phosphate incubation resulted in an increase in mean molecular weight of all crystallin fractions and the occurrence of high-molecular weight material, partly formed by disulphide bonds. The glycated crystallins showed a decrease of tryptophan fluorescence and an increase of a specific non-tryptophan fluorescence. This fluorescence was, however, not exclusively associated with the high molecular weight protein, but was present in all protein fractions.
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Affiliation(s)
- M A van Boekel
- Department of Biochemistry, University of Nijmegen, The Netherlands
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30
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Abstract
The effect of glucose on the insolubilization of lens proteins was investigated in the presence of visible light. The amount of glucose-induced insolubilization of lens proteins showed a dose-dependent increase. The velocity of insolubilization accelerated under acidic conditions. These results suggest that this phenomenon may be due to the direct action of glucose rather than glycosylation. 1H-NMR spectroscopy results suggest that the action of glucose might be to induce conformational changes, and aggregation of the proteins. The in vitro observation of glucose-derived insolubilization of the lens proteins may be similar to that observed in diabetic mellitus. Elevated free glucose per se may have a role in diabetic cataractogenesis in addition to the metabolism of glucose to sorbitol and osmotic changes to the lens. Protein structural perturbation by glucose was demonstrated with isolated proteins from the aged normal human lenses over 40 years and may contribute to senile cataractogenesis. The results suggest that elevated lens glucose may act directly as one of the triggers of cataractogenesis.
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Affiliation(s)
- A Kamei
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan
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31
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Abstract
Hyperglycemia is increasingly regarded as the cause of the diabetic complications, in particular via the ability of glucose to glycate proteins and generate Maillard browning products which cross-link proteins and render them brown and fluorescent in vitro. Similar changes occur in vivo to long-lived proteins in diabetes mellitus as well as in ageing. The evidence supporting this route of glucose toxicity is discussed in the context of the ability of glucose to oxidize in vitro (catalyzed by trace amounts of transition metal) generating hydrogen peroxide, highly reactive oxidants, and protein-reactive ketoaldehyde compounds. It is suggested that protein browning in vivo may not result from the reactions of glucose with protein but from the transition metal-catalyzed reactions of other small autoxidisable substrates, such as ascorbate, with protein. Overall, studies of glycation and protein browning suggest a critical role for oxidative processes perhaps involving decompartmentalized transition metals and a variety of low molecular weight reducing agents in diabetes mellitus and ageing.
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Affiliation(s)
- S P Wolff
- Department of Clinical Pharmacology, University College London, UK
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32
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Slight SH, Feather MS, Ortwerth BJ. Glycation of lens proteins by the oxidation products of ascorbic acid. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1038:367-74. [PMID: 2340296 DOI: 10.1016/0167-4838(90)90250-j] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bovine lens water-soluble proteins were incubated with [I-14C]ascorbic acid (ASA) for 6 days, and the incorporation into protein was measured at daily intervals. Aliquots were also withdrawn to determine the distribution of label among the various ASA oxidation products. A linear incorporation into protein was observed in the presence of NaCNBH3, however, little or no incorporation was seen in its absence. TLC analysis showed a complete loss of ASA by day 3, whereas both dehydroascorbate (DHA) and diketogulonic acid (DKG) remained constant for 6 days, consistent with the linear incorporation into protein. The amino acid composition of the proteins glycated in the presence of NaCNBH3 was identical to controls except for a 70% reduction in lysine residues and a corresponding increase in an unknown product which eluted slightly earlier than methionine. In the absence of NaCNBH3 lysine decreased linearly to 20% with an additional decrease in arginine and histidine at later times concurrent with protein crosslinking. DHA and DKG were prepared and incubated directly with lens proteins for an 8 day period. Both compounds glycated lens protein as evidenced by an increased binding to a boronate affinity column. SDS-PAGE showed that both compounds were also capable of causing protein crosslinking. DHA is apparently capable of reacting directly with protein since glycation was observed with the ASA analog, reductic acid, which can be oxidized to dehydroreductic acid, but which cannot be hydrolyzed to an open chain structure. DHA also produced a lysine adduct which was not obtained with DKG, supporting the idea that both species have glycating ability.
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Affiliation(s)
- S H Slight
- Mason Institute of Ophthalmology, University of Missouri, Columbia 65212
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33
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Oimomi M, Maeda Y, Baba S, Iga T, Yamamoto M. Relationship between levels of advanced-stage products of the Maillard reaction and the development of diabetic retinopathy. Exp Eye Res 1989; 49:317-20. [PMID: 2767180 DOI: 10.1016/0014-4835(89)90103-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- M Oimomi
- Second Department of Internal Medicine, Kobe University School of Medicine, Japan
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Oimomi M, Hata F, Igaki N, Nakamichi T, Baba S, Kato H. Purification of alpha-ketoaldehyde dehydrogenase from the human liver and its possible significance in the control of glycation. EXPERIENTIA 1989; 45:463-6. [PMID: 2721637 DOI: 10.1007/bf01952031] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alfa-ketoaldehyde dehydrogenase, which was extracted and purified from human livers, may act on carbonyl compounds, such as 3-deoxyglucosone, and be involved in the control of glycation (Maillard reaction) in the body.
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Affiliation(s)
- M Oimomi
- Second Department of Internal Medicine, Kobe University School of Medicine, Japan
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