Long-chain lipids could help prevent dry eye disease, suggest study

Very long-chain tear film lipids produced by fatty acid elongase ELOVL1 prevent dry eye disease in mice.

The anatomy of the eye and schematic diagram of tear film composed of 3 layers (glycocalyx layer, aqueous layer, and lipid layer). Most of the proteins (mainly mucin) in the glycocalyx layer are secreted from goblet cells. The components of the aqueous layer are secreted from lacrimal glands. Meibum lipids are secreted from meibomian glands and form the TFLL.
The anatomy of the eye and schematic diagram of tear film composed of 3 layers (glycocalyx layer, aqueous layer, and lipid layer). Most of the proteins (mainly mucin) in the glycocalyx layer are secreted from goblet cells. The components of the aqueous layer are secreted from lacrimal glands. Meibum lipids are secreted from meibomian glands and form the TFLL.

Long-chain lipids in the most superficial layer of the tear film cause serious dry eye malady when they were abbreviated in mice — an outcome that could help grow new medications for the illness.

With computers, cell phones, and contact focal points now basic to present day life, anyone out of each 10 Japanese individuals — endure dry eye sickness.

The tear film performs different capacities, including keeping up a smooth surface for light refraction, greasing up the cornea and conjunctiva, and providing the cornea with oxygen and supplements. Numerous might think tears are only water, however really the tear film is made out of three essential layers: mucin, water and lipids, the last of which keeps water dissipation from the visual surface and ensures against contamination.

Around 80 percent of dry eye ailment cases are caused by anomalies in this lipid layer. In spite of the fact that medications focusing on the water and mucin layers are accessible, no medication has been made to focus on the lipid layer.

Tear film lipids are emitted by the meibomian organ and are called meibum, a sub-atomic chain made out of cholesteryl esters and wax esters. The meibum carbon chain is by and large long, having from 20 to 34 constituent carbons. Yet, much about meibum stays hazy, for example, the criticalness of its long chains and its part in anticipating dry eye malady.

The exploration group drove by Akio Kihara of Hokkaido University made mice whose Elovl1 quality, which encodes a protein that prolongs unsaturated fat chains, was erased from all over however the skin, realizing that thumping out the quality in the skin is deadly. The group watched that when youthful, the knockout mice flickered as often as possible and showed indications of dry eye illness, for example, expanded water vanishing from the tear film.

Photographs of the eye morphologies of 5-mo-old female control [Elovl1+/+ Tg(IVL-Elovl1)30] and 5- to 19-mo-old male/female Elovl12/2 Tg(IVL-Elovl1)30/45 mice (1 male and 2 females). Original scale bars, 1 mm.
Photographs of the eye morphologies of 5-mo-old female control [Elovl1+/+ Tg(IVL-Elovl1)30] and 5- to 19-mo-old male/female Elovl12/2 Tg(IVL-Elovl1)30/45 mice (1 male and 2 females). Original scale bars, 1 mm.
Following five months, a considerable lot of the mice created overcast corneas. The corneal variations from the norm are accepted to have been caused by drawn-out dry eyes, which restrained self-repair of the harmed cornea.

Kihara said, “These results indicate Elovl1 is closely linked to the synthesis of very long-chain meibum, which appear to be essential to preventing dry eye disease. “Our results could help develop new drugs to treat and prevent the dry eye disease, such as agents that promote the secretion of very long-chain meibum or eye drops containing these lipids.”

The researchers also found that the knockout mice had less very long-chain meibum (≥ 25 carbons), but more short-chain meibum.

The study is originally published in FASEB Journal.