Antibacterial Fat, DIY Pancreas

Columnist
Graduate Division

Happy New Year! Isn’t it great that while we were all on vacation, enjoying the holidays with our friends and families, science kept moving forward? There is always something exciting to report on (I hope this will always continue to be true), so here is a small and completely subjective selection. [Enter Messenger].

Antibacterial Fat

What happens at the front line of a Staphylococcus aureus bacterial skin infection? There are sentinel immune cells standing guard in all our tissues—but are they alone responsible for fighting off microbes, or do other tissue cells contribute to the battle?

In this year’s first issue of Science, L.J. Zhang and colleagues in the Gallo lab at UCSD published the intriguing finding that dermal adipocytes—skin fat cells—are a critical part of fighting S. aureus skin infection. Following their initial observation that these cells expanded on the skin of mice with S. aureus infection, the authors demonstrated that mice were even more susceptible to infection following genetic or chemical inhibition of adipocyte expansion. Immune cells still functioned normally during these infections, indicating the S. aureus-fighting function of adipocytes is not simply due to their supporting of immune cells. 

They went on to show that cathelicidin antimicrobial peptide (CAMP) is released by adipocytes and has antibacterial activity. This means that skin fat tissue, far from being a passive tissue, plays an active role in fighting bacterial skin infections, while the rest of the immune system mobilizes forces (which takes time). Because CAMP also has pro-inflammatory functions, the authors speculate that it may function in the crosstalk between adipose tissue and immune cells—an interaction that is known to be chronically active in obesity.

It’s well appreciated that the immune system is a complex, many-armed fighting machine, and these findings, as well as previous research finding a role for certain epithelial cells in various immune responses, may be the beginning of a major paradigm shift in the way we understand tissue biology and the boundaries between different tissue functions.

Sources: Science, EurekAlert!

DIY Biomedical Engineering

An eloquent article full of suspense and intrigue was published by Dan Hurley in WIRED on Christmas Eve. It discussed the secret underground efforts of technologically advanced parents—software engineers by day, for example—who have been hacking their diabetic kids’ blood sugar sensors. One parent hacked the sensor to send its readings to an application he created for his smart phone, allowing for 24/7 monitoring of his son’s blood sugar and much faster responses to blood sugar dips. Another man wrote an app that automatically calculated the amount of glucose or insulin needed to correct high or low blood glucose levels. After hearing about these homegrown inventions, many other tech-savvy parents have followed suit and developed similar apps.

The FDA does not interfere with these kinds of home solutions as long as they stay within the household. People with the skills to design these hacks can discuss their idea with others, but can’t share their algorithms or code. They understand the danger of non-tech-savvy people attempting to recreate their hacks, and urge them to remain cautious. The reliance on a good internet connection for these apps to function is also a major limitation.

Rumor in this community has it that someone, somewhere, has successfully hacked a “bionic pancreas”—just as a normal pancreas measures blood glucose levels and releases the appropriate amount of insulin to allow cells to import that glucose, so his smart phone imports his blood glucose readings, calculates the appropriate insulin level and communicates that number to an implanted insulin pump. Whether or not this person truly succeeded in linking these medical devices through a phone app remains unconfirmed.

What is true is that a number of research groups are making progress toward such a device, with several clinical trials in progress (see, e.g., http://jdrfconsortium.jaeb.org or http://www.artificialpancreas.org). 

Such a device, homegrown or commercial, would be a powerful technological solution for diabetics. Even as labs are working to develop biological implants of lab-grown insulin-producing cells and researching how to suppress immune responses to those implants, or seeking to develop a commercial artificial pancreas, parents around the country (perhaps the world) are working toward their own workarounds as they manage their children’s diseases. Necessity is the mother of invention.

Source: WIRED, JDRF Consortium, ArtificialPancreas.org