Of all the human diseases, you'd think that acne would be an easy one to give mice -- not so much.

Researchers have been trying to give mice acne, in hopes of developing a better treatment for people, for some time now. The problem is, rodents don't have oily enough skin for the pimple inducing bacteria to survive. Existing animal models -- bald mice and rabbit ears -- have problems. The bald mice are immunocompromised and the rabbit ears don't get infected -- something to sweat when you're studying acne.

At the University of California in San Diego, scientists are using a method developed in the early '80s to deal with the issue. In 1982, small Teflon chambers were inserted under the skin in guinea pigs. When bacteria were injected into the tiny cavities, localized infection could be studied.

In a recent report, the researchers describe how they retrofitted the approach using a system in which human cells (similar to cells that surround hair) reside in the chamber. The ensemble was implanted into the bellies of mice. And ... the human cells survived to produce lipids! Once Propionibacterium acnes (the bacteria associated with acne) was injected into the center, the mice had a bona fide bioengineered pimple.

After letting the mouse zits fester a bit, the researchers collected liquid from the center and analyzed it. They identified a series of proteins -- some from the mouse, some from the human cells and some from the bacteria. The authors anticipate the new model will be useful in developing anti-acne medications and vaccines.