Exp Eye Res. 2004 Dec;79(6):761-8. Related Articles, Links

Lens lipids and maximum lifespan.

Borchman D, Yappert MC, Afzal M.

Department of Ophthalmology and Visual Science, University of
Louisville, Louisville, KY 40292, USA.

Unlike in most organs, the lipid composition of lenses varies
dramatically among species and with age. The focus of this study is to
assess how these changes relate to lifespan. Studies on cataract
suggest that the lens may serve as a window into the processes leading
to accelerated mortality. As a first step toward elucidating cellular
processes in the lens that may serve as markers for accelerated
mortality, we examined the correlation between species-dependent and
age-related lens lipid compositional differences and maximum life span.
We included data from camels, which, even in old age, rarely develop
cataracts although they live under adverse conditions. Camel lens
lipids were mainly composed of sphingolipids (77%) and
phosphatidylcholines (23%). Bovine lens lipid composition was
comparable to a previous study, and both bovine lens sphingolipids,
phosphatidylcholines and camel lens phosphatidylcholines content fit
well (within the 95% confidence limits) in the curve obtained by
plotting maximum life spans of other species with sphingolipids and
phosphatidylcholines. Lifespan was directly related to lens
sphingolipid content and indirectly related to lens phosphatidylcholine
content. The camel lens sphingolipid value was significantly above the
curve for other species. Except for the camel lens nucleus, lipid order
and sphingolipid content were linearly related, [Formula: see text]
with a slope of 0.85+/-0.07, and intercept of 6.9+/-3.8. Lipid phase
transition temperature and sphingolipid content were also linearly
related, [Formula: see text] with a slope of 0.20+/-0.07, and intercept
of 21.7+/-5.3. Our data support the hypothesis that humans have adapted
so that their lens membranes have a high sphingolipid content that
confers resistance to oxidation, allowing these membranes to stay clear
for a relatively longer time than is the case in many other species.
Age-related changes in human lens lipid composition may serve as a
marker for oxidative stress and may reflect systemic oxidative insult,
providing a window into the health of an individual.

PMID: 15642313 [PubMed - in process]

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