No turnover in lens lipids for the entire human lifespan

Autor: Roger J.W. Truscott, Jessica R Hughes, Alan Williams, Stephen J. Blanksby, Vladimir Levchenko, Todd W. Mitchell
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: eLife
eLife, Vol 4 (2015)
ISSN: 2050-084X
Popis: Lipids are critical to cellular function and it is generally accepted that lipid turnover is rapid and dysregulation in turnover results in disease (Dawidowicz 1987; Phillips et al., 2009; Liu et al., 2013). In this study, we present an intriguing counter-example by demonstrating that in the center of the human ocular lens, there is no lipid turnover in fiber cells during the entire human lifespan. This discovery, combined with prior demonstration of pronounced changes in the lens lipid composition over a lifetime (Hughes et al., 2012), suggests that some lipid classes break down in the body over several decades, whereas others are stable. Such substantial changes in lens cell membranes may play a role in the genesis of age-related eye disorders. Whether long-lived lipids are present in other tissues is not yet known, but this may prove to be important in understanding the development of age-related diseases. DOI: http://dx.doi.org/10.7554/eLife.06003.001
eLife digest Every cell is surrounded by a membrane made primarily of molecules called lipids. This membrane protects the cell and controls which molecules pass into and out of it. To keep the membrane in good working order, its lipids are regularly broken down and replaced with fresh molecules. However, some cells—such as the cells that make up most of the lens of the eye—lack easy access to the cell machinery that renews the membrane. The lens grows throughout life by adding new cells to the outside of the lens, but the center of the lens—also known as the lens nucleus—contains the same cells that were present at birth. This raises the question of whether the lipids in the membranes of these cells also remain in the cells for life. From 1955 to 1963, above-ground test explosions of nuclear weapons caused a large amount of a radioactive form of carbon called carbon-14 to be released into the atmosphere. In subsequent years, these levels have decreased again as the carbon-14 is absorbed into the oceans or incorporated into biological molecules—like lipids. This doesn't affect the molecules, as carbon-14 works just like normal carbon. However, as the proportion of carbon-14 in a group of molecules reflects the amount of carbon-14 in the atmosphere when the molecule was made, this allows the age of the molecule to be determined. Hughes et al. used a technique called mass spectrometry to measure the carbon-14 in lens nuclei donated by 23 people who were born between 1948 and 1993. This revealed that the proportion of carbon-14 in the total carbon content of the lipids in the nucleus could be used to accurately predict the year of birth of the donor. Therefore, the lipids in your lenses when you are born remain with you for your entire life. This finding could help us to understand age-related sight disorders, such as cataracts. Further research could also investigate whether there are any similarly long-lasting lipids in other body tissues, and whether these affect how other age-related diseases develop. DOI: http://dx.doi.org/10.7554/eLife.06003.002
Databáze: OpenAIRE
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