Despite living in arid deserts, camels rarely suffer eye disease. Now a project that began with a UAE grant is studying how proteins in the tears of camels could help treat severe eye conditions in humans.
Hope in the eye of a camel for human medicine
Scientific studies of camels have provided important clues to everything from understanding advanced reproduction techniques to saving endangered species.
Now a research project with staff at Al Ain's UAE University, and Alfaisal University in Saudi Arabia, is using camels owned by the President, Sheikh Khalifa, to understand how the proteins in camel tears could improve human medicine.
The aim of the project, which started in 2007 with a grant from UAE University, is to find an effective medicine to treat Sjogren's syndrome, an autoimmune disease that destroys the eyes' ability to produce tears, making them more prone to bacterial and viral infections.
"Patients often complain of dryness of the eyes in the form of foreign body sensation or grittiness," explains Professor Walter Conca, MD, a former UAE University associate professor who now works at Alfaisal University Medical College and King Faisal Specialist Hospital and Research Centre in Riyadh.
"It can be extremely disturbing. We thought that the camel, which is naturally living in the most arid climate on the globe, must have some sort of protective system which allows it to live in the desert.
"This was our hypothesis and we started collecting the tears from the animals and finding the basic components of the protein molecules."
Sjogren's syndrome is often developed by people with other autoimmune and rheumatic disorders such as rheumatoid arthritis, lupus and primary biliary cirrhosis of the liver. When Prof Conca worked in the UAE he also saw patients at Tawam and Al Ain hospitals. Many of them, he says, suffered from autoimmune disease and were searching for ways to manage their condition.
Artificial tears in the form of eye drops are the only way of managing the dry eye disorder. But they are neither very effective nor offer a very advanced solution. Camels, however, suffer very few eye diseases and seem very well adapted to living comfortably in the driest and dustiest of environments.
If the team can identify the proteins that are helping to fight off infections and preventing anything from inhibiting the eyes' ability to produce tears, they can help treat dry eyes in humans, Prof Conca says.
They have received a 2 million riyal grant (Dh1.9 million) from Saudi Arabia's King Abdulaziz Centre for Science and Technology.
"Our hypothesis is based on the fact that camels have adapted incredibly well to living in the desert," says Professor Michael Conlon, a researcher from UAE University. "There, winds often blow sand into the air and to shield their eyes, the camels have long eyelashes that catch most of the grains.
"But the eyelashes don't do all the work. The camels also have effective tears which help lubricate their eyes and protect them from infection. So if we analyse all the compounds in camel tears, we might find a protein or something that can be added to artificial tears to make them a lot better.
"This is all about adaptation. The camels have adaptations that no other animals have that don't live in these extreme conditions. We can learn from these and use them to our advantage," says Prof Conlon.
"At the moment we don't know what we're going to find, so we can't say when the end will be."
The researchers are working with a team at an Al Ain camel farm and reproduction centre that is owned by Sheikh Khalifa. The 500 dromedary camels kept at Hili Embryo Transfer Surgery Centre make perfect subjects, and the head veterinarian, Dr Alex Tinson, is happy for his animals to participate in the research.
"Here, we try to mix research with practical things," Dr Tinson says. "Obviously we want to breed first-class camels, that's the practical side of things. But we also do a lot of research, especially into reproduction techniques.
"And the tear project is another example of how we can learn from the camels. Now we are appreciating the camel a lot more. We have discovered that they have a totally unique immune system which we can use to learn more about human medicine."
Dr Tinson moved to the UAE from Australia after being approached in 1988 while taking part in the Great Australian Camel Race, said to be the world's longest endurance race.
He came to Abu Dhabi for just two years to set up a specialist centre but is now in his 25th year.
As well as head veterinarian of the Hili centre, he is also director of laboratories and research, and manages all the Scientific Centres and Presidential Camels under the Department of President's Affairs.
Along with his colleague Dr Rajesh Singh, Dr Tinson's role is to select the camels for the project and collect the tears using a plastic syringe with the needle removed.
It is important not to overstimulate the eyes as the chemical compounds of induced tears (such as those produced by cutting onions or being poked in the eye) are different to the tears that occur naturally to lubricate the eye.
The syringe is inserted under the bottom eyelid for a few seconds while a handler holds the camel's head still. Gloves are worn to avoid any contamination of the samples.
Once in the syringes, the tears are emptied into large test tube containers. A special solution is added to stop any enzyme activity from killing the proteins.
It is already known that camel tear fluid has three main layers: an outer layer made up of lipids that protect from evaporation, an aqueous middle layer that contains the proteins and an inner layer containing carbohydrates.
It is the same model as human tears, but the proteins and molecule formations are different. Camels can break down any foreign bodies which land in the eye much more easily, and they also do not seem to be affected by anything (diseases or foreign objects) which could inhibit their ability to produce tears.
"We have found some very interesting things where we have compared human with camel tears," Prof Conca says.
"Lysozymes, for example, which breakdown bacteria, viruses and insects in camels have two molecular sizes whereas humans only have one.
"We hope that by analysing the composition of camel tear fluid, and by making discoveries like this, we could facilitate or assist or help in designing artificial tears for humans."
Prof Conca hopes to publish some of the team's initial work soon. "I hope within six months to have the definitive answer about the antibody composition," he says, "and we will go ahead and publish that initial work and see whether the initial observations are also pertinent to other strains of camel."
While other big mammals such as horses, elephants and whales have been studied in depth for decades, it is only recently that camels have received the same levels of attention.
"I don't think we have underestimated the camel," says Prof Conca. "I think since the Middle East is just beginning to expand, it's able to adapt the knowledge acquired elsewhere and bring it to the region here to look for things [in science] that are probably of value and unknown. It takes time."