Evidence of a glycemic threshold for the formation of pentosidine in diabetic dog lens but not in collagen

Nagaraj, Ram H.; Kern, T. S.; Sell, D. R.; Fogarty, J.; Engerman, R. L.; Monnier, V. M.

doi:10.2337/diabetes.45.5.587

Cited by 12 publications

(5 citation statements)

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“…In mammals the concentration of pentosidine increases over the life span of the animal. The rate of accumulation of pentosidine, which is formed by the non-enzymatic glycosylation of lysine and arginine residues, is accelerated in mammals with hyperglycaemia (Sell and Monnier, 1989; Grandhee and Monnier, 1991;Dyer et al, 1991a,b;Sell et al, 1992;Reiser, 1994;Nagaraj et al, 1996). In agreement with results from mammalian studies, Iqbal et al (1997) detected pentosidine in the tissues of broiler breeder hens.…”

Section: Evidence From Glycation/glycoxidation Studiessupporting

confidence: 71%

“…Current theory suggests that aging is largely a consequence of the synergistic relationship between free radical damage and the formation of advanced Maillard products (non-enzymatic collagen crosslinks) (Masoro et al, 1989;Kristal and Yu, 1992). The increased avian metabolic rate should expose birds to a higher concentration of oxygen free radical production and, consequently, accelerated tissue damage, while the hyperglycaemia and raised body temperature should promote the formation of advanced Maillard products which may be involved in aging-related tissue degeneration (Sell and Monnier, 1989; Grandhee and Monnier, 1991;Dyer et al, 1991a,b;Sell et aI., 1992;Reiser, 1994;Cefalu et al, 1995;Nagaraj et al, 1996). Yet most avian species live longer than mammals of a comparable size.…”

Section: Introductionmentioning

confidence: 99%

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In the defence against hyperglycaemia: an avian strategy

Klandorf

Probert

Iqbal

1999

World's Poultry Science Journal

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Section: Evidence From Glycation/glycoxidation Studiessupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

In the defence against hyperglycaemia: an avian strategy

Klandorf

Probert

Iqbal

1999

World's Poultry Science Journal

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“…It can therefore be concluded that ascorbate is most likely the precursor of LM-1 in the lens. However, pentosidine formation in lenses from poorly controlled dogs may also be linked to membrane permeability increase and increased crystallin glycoxidation [30]. These data clearly indicate that the biosynthetic mechanisms for the formation of advanced Maillard reaction products are unclear, and that the precursor may vary according to ambient glucose concentration.…”

Section: Glycoxidation and Intracellular Agesmentioning

confidence: 90%

Structure of advanced Maillard reaction products and their pathological role

Monnier

Nagaraj

Portero‐Otín

et al. 1996

Nephrology Dialysis Transplantation

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In this article we review recent progress and controversies relating to three areas of the field of advanced glycosylation end-products (AGE). A controversy exists as to whether pyrraline, an AGE detectable by immunohistochemistry in kidneys from patients with renal failure, exists in vivo. Recent data from the authors' laboratory revealed that pyrraline is present in alkaline or protease digests from human skin and plasma. However, the amounts are very low and pyrraline was found to undergo further reactions to form an ether with itself (dipyrraline) as well as a thioether with cysteine. This high reactivity of pyrraline may explain the difficulty of quantitating it accurately in biological material. In contrast, the glycoxidation products carboxymethyllysine (CML) and pentosidine are stable, very resistant to acid hydrolysis and easy to quantitate. They are present in elevated concentrations in the extracellular matrix in diabetes mellitus and ageing. In the diabetic human lens, CML is not elevated, in contrast to pentosidine, suggesting a different mechanism of formation. Recent data in diabetic dogs have shown that pentosidine is elevated only in lenses from poorly controlled dogs, in contrast to LM-1, a fluorophore thought to arise from ascorbate. Further studies are needed to clarify the intracellular mechanism of glycoxidation. The greatest concentrations of AGEs and glycoxidation products are found in patients with end-stage renal disease, and they are almost completely normalized by renal transplantation. Comparison of peritoneal dialysis (PD) with haemodialysis (HD) showed that PD is associated with lower plasma protein pentosidine, possibly due to selective transport of pentosidine-rich protein across the peritoneal wall. Fractionation of plasma proteins from ESRD patients by size showed that 90% of pentosidine is linked to HMW protein and 1-2% is in free form. The mechanism of accelerated glycoxidation in ESRD is still not understood.

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“…Tel: 216-368-6613; Fax: 216-844-1810. diabetic complications by nonenzymatic glycation is the demonstration that levels of Maillard reaction products correlate with cumulative severity of diabetic complications (7) and the degree of glycemic control in dogs (8). A role for advanced glycation in diabetic complications is also suggested by virtue of the fact that aminoguanidine, an inhibitor of glucose-mediated protein cross-linking both in vitro and in vivo (9,10), has beneficial effects on the progression of nephropathy (11), retinopathy (12), neuropathy (13), and a host of diabetic processes (14,15) in diabetic rodents.…”

Section: The Recent Results Of the Diabetes Control And Complicationsmentioning

confidence: 99%

Novel Degradation Pathway of Glycated Amino Acids into Free Fructosamine by a Pseudomonas sp. Soil Strain Extract

Gerhardinger

Marion

Rovner

et al. 1995

Journal of Biological Chemistry

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A Pseudomonas sp. soil strain, selected for its ability to grow on epsilon-(1-deoxyfructosyl) aminocaproic acid, was induced to express a membrane-bound enzymatic activity which oxidatively degrades Amadori products into free fructosamine. Apparent Km values for fructosyl aminocaproate, epsilon-fructosyl lysine, fructosyl glycine, and ribated lysine were 0.21 mM, 2.73 mM, 3.52 mM, and 1.57 mM, respectively. The enzyme was also active against alpha-fructosyl lysine and borohydride-reduced Amadori product, weakly active with ribated and glycated polylysine, and inactive with reducing sugars, amino acids, and glycated proteins. The enzymatic activity was highest at pH 6.5 and 25 degrees C in 0.1 M sodium phosphate, while over 80% of the activity was lost above 65 degrees C. Complete inhibition was observed by HgCl2, NaN3, and NaCN suggesting a role for SH groups and copper in the enzymatic activity. The reaction products were characterized by 1H NMR, 13C NMR, and GC/MS and found to correspond to 1-deoxy-1-aminofructose, i.e. free "fructosamine," and adipic acid. Confirmation of the free fructosamine structure was based on the complete spectroscopic identity of the borohydride reduction product with commercially available glucamine (1-amino-1-deoxyglucitol). The new enzyme is provisorily classified as fructosyl N-alkyl amino acid oxidase (EC 1.5.3) (fructosyl-amino acid:oxygen oxidoreductase) and may thus belong to a novel class of "Amadoriases" which deglycate Amadori products oxidatively. In contrast, however, the new enzyme acts on the alkylamine bond rather than the ketoamine bond of the Amadori product.

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Evidence of a glycemic threshold for the formation of pentosidine in diabetic dog lens but not in collagen

Cited by 12 publications

References 0 publications

In the defence against hyperglycaemia: an avian strategy

In the defence against hyperglycaemia: an avian strategy

Structure of advanced Maillard reaction products and their pathological role

Novel Degradation Pathway of Glycated Amino Acids into Free Fructosamine by a Pseudomonas sp. Soil Strain Extract

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