ArticleRejuvenation research2016
Racemized and Isomerized Proteins in Aging Rat Teeth and Eye Lens.
Article in Rejuvenation research, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
4 citing papers in PubMed, 11 citations in OpenAlex.
- Young Plasma Rejuvenates Blood DNA Methylation Profile, Extends Mean Lifespan, and Improves Physical Appearance in Old Rats.The journals of gerontology. Series A, Biological sciences and medical sciences · 2024Article
- Article
- Deuteration protects asparagine residues against racemization.Amino acids · 2016Article
- A Rat Treated with Mesenchymal Stem Cells Lives to 44 Months of Age.Rejuvenation research · 2016Article
Corrections and comments
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Authors and funding
4 authors at 3 institutions in 3 countries.
Funding
Abstract
The quantification of aspartic acid racemization in the proteins of nonmetabolically active tissues can be used as a measure of chronological aging in humans and other long-lived organisms. However, very few studies have been conducted in shorter-lived animals such as rodents, which are increasingly used as genetic and metabolic models of aging. An initial study had reported significant changes in the ratio of d- to l-aspartate in rat molars with age. Using a sensitive HPLC method for the determination of d- and l-aspartate from protein hydrolysates, we found no accumulation of d-aspartate in the molars of 17 rats that ranged in age from 2 to 44 months, and the amount of d-aspartate per molar did not correspond with molar eruption date as had been previously reported. However, developing an alternate approach, we found significant accumulation of isomerized aspartyl residues in eye lens proteins that are also formed by spontaneous degradation processes. In this study, we used the human protein l-isoaspartate/d-aspartate O-methyltransferase (PCMT1) as an analytical reagent in a sensitive and convenient procedure that could be used to rapidly examine multiple samples simultaneously. We found levels of isomerized aspartyl residues to be about 35 times higher in the lens extracts of 18-month-old rats versus 2-month-old rats, suggesting that isomerization may be an effective marker for biological aging in this range of ages. Importantly, we found that the accumulation appeared to plateau in rats of 18 months and older, indicating that potentially novel mechanisms for removing altered proteins may develop with age.
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Registered trials
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