Science/Tech

Why the Human Eye May Hold the Key to Fighting Life-Threatening Bacterial Infections

eye
Image Ahmed Sinan/Flickr

The human eye regularly confounds scientists and ordinary folk alike. Recently, the University of California, Berkeley has added a new power to the human eye. Researchers discovered a compound lining the cornea that easily battles various harmful microbes. The new knowledge could help scientists develop inexpensive new antimicrobial drugs.

The team found that small particles of the keratin protein, found in the eye, staves off infectious diseases. And, when scientists made their own synthetic versions of keratin, it emerged victorious against flesh-eating bacteria as well as the microbes that cause strep throat, diarrhea, staph infections and cystic fibrosis lung infections.

Previous research on similar naturally-occurring antimicrobial molecules found them to be useless when up against salt. That Achilles heel is unfortunate because salt exists naturally in the human body. However, keratin proved victorious in a water- and saline-based solution, meaning that keratin would be able to stay active in the face of salt concentrations.

Excitingly, keratin fragments are really easy to manufacture, meaning that they could serve as low-cost microbial agents. Perhaps best of all, since keratin is already found in the body, it is unlikely that giving people doses of the fragment would provoke harmful side effects in patients.

"We used to think that cytokeratins were primarily structural proteins, but our study shows that these fragments of keratin also have microbe-fighting capabilities," said study lead author Connie Tam, an assistant research scientist. "Cytokeratin 6A can be found in the epithelial cells of the human cornea as well as in skin, hair and nails. These are all areas of the body that are constantly exposed to microbes, so it makes sense that they would be part of the body's defense."

The researchers became intrigued by cytokeratins when they noticed that the human eye has a remarkable ability to fight infection. They noticed that no bacteria lived on the surface of the cornea, and lab investigations found that corneal tissue beat bacterial infections handily. Researchers even tried to use tissue paper to damage corneal cells and plaster the eyes with bacteria; that still did not work.

Subsequent research found that cytokeratins were the secret to the eye's strength against infections. Indeed, when scientists manipulated the genes of mice in order to suppress the creation of cytokeratin, bacterial infections in the eye multiplied fivefold.

The findings will be published in the October issue of the Journal of Clinical Investigation.

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