Gut Bacteria Dramatically Boosts Cancer Immunotherapy


Science has confirmed that a balanced gut—where good bacteria outnumber bad—is often linked to a stronger immune system. Now, researchers in the lab of Thomas Gajewski, professor of pathology and medicine at the University of Chicago (UC), have discovered that good bacteria can also dramatically amplify the effects of cancer immunotherapy treatments. Their results are published in the November issue of the journal Science.

When the researchers introduced a particular strain of bacteria into the digestive tracts of mice with melanoma, they were startled to find it boosted the animals’ immune systems so effectively, the tumor-reducing effects were comparable to anti-cancer drugs known as checkpoint inhibitors, which keep the immune system from becoming overactive.

These inhibitors, however, which can be dramatically effective at reducing tumors when they do work, only do so in a third or fewer patients who use them.

The researchers already knew that gut bacteria had been shown to effect systemic immunity, but they came to their exciting discovery of its effect in cancer treatment by accident. Mice purchased from Jackson Laboratory (JAX) had a more notably robust immune response to small tumors implanted under their skin. Mice from Taconic Biosciences (TAC), however, showed weak immune response. When researchers put the mice from both sources together for three weeks, these discrepancies disappeared. They suspected that the mice shared microbes that enhanced their immunity.

“Gut bacteria influence the differentiation and function of systemic T cell subsets so that they respond faster and more efficiently to stimuli,” says lead author Ayelet Sivan, a Ph.D. student in Gajewski’s lab who designed and executed the experiments.

To test their theory that the microbes were responsible for the improved immune response, they transferred fecal matter from JAX mice to the stomachs of TAC mice, with positive results. The treated TAC mice had stronger immune responses and slower tumor growth.

When they compared the bacterial transfer effects with the effects of a checkpoint inhibitor drug, they found that the bacteria treatment was just as effective.

As soon as five days following the start of fecal transfer, Sivan says, “We saw that there was a delay in tumor outgrowth and that there was a boost in tumor specific immune responses.”

In their search for which specific bacteria made the difference, one genus stood out from over 254 strains: Bifidobacterium. Once identified, they treated the TAC lower-immunity mice with Bifidobacterium directly, without fecal transfer, and still, the immune boosting, tumor-fighting results remained high. 

As for how this occurred, the researchers suspect that Bifidobacterium, which appear to have colonized a compartment in the mouse intestines, interacted with roaming dendritic cells, which hunt for threats and present them to T cells. In response, the T cells attacked the tumors.

Sivan tells mental_floss that their study focused specifically on melanoma cancer because “it is well established that immunotherapies can be effective in melanoma, and that the immune response plays an important role in the control of melanoma growth and treatment.” But future research will look at other cancers that benefit from immunotherapies, as well as other bacteria strains. “There are many open questions as to the mechanism and signals through which Bifidobacterium leads to improved antitumor immunity, which may lead to novel therapies that may eventually replace the use of the bug itself,” she says.

They are eager to get to the stage where the bacteria can be tested for efficacy in humans and will continue to research other bacteria strains and their effect on antitumor immune responses. 

MARS Bioimaging
The World's First Full-Color 3D X-Rays Have Arrived
MARS Bioimaging
MARS Bioimaging

The days of drab black-and-white, 2D X-rays may finally be over. Now, if you want to see what your broken ankle looks like in all its full-color, 3D glory, you can do so thanks to new body-scanning technology. The machine, spotted by BGR, comes courtesy of New Zealand-based manufacturer MARS Bioimaging.

It’s called the MARS large bore spectral scanner, and it uses spectral molecular imaging (SMI) to produce images that are fully colorized and in 3D. While visually appealing, the technology isn’t just about aesthetics—it could help doctors identify issues more accurately and provide better care.

Its pixel detectors, called “Medipix” chips, allow the machine to identify colors and distinguish between materials that look the same on regular CT scans, like calcium, iodine, and gold, Buzzfeed reports. Bone, fat, and water are also differentiated by color, and it can detect details as small as a strand of hair.

“It gives you a lot more information, and that’s very useful for medical imaging. It enables you to do a lot of diagnosis you can’t do otherwise,” Phil Butler, the founder/CEO of MARS Bioimaging and a physicist at the University of Canterbury, says in a video. “When you [have] a black-and-white camera photographing a tree with its leaves, you can’t tell whether the leaves are healthy or not. But if you’ve got a color camera, you can see whether they’re healthy leaves or diseased.”

The images are even more impressive in motion. This rotating image of an ankle shows "lipid-like" materials (like cartilage and skin) in beige, and soft tissue and muscle in red.

The technology took roughly a decade to develop. However, MARS is still working on scaling up production, so it may be some time before the machine is available commercially.

[h/t BGR]

More Studies See Links Between Alzheimer's and Herpes

Although it was discovered in 1906, Alzheimer’s disease didn’t receive significant research attention until the 1970s. In 1984, scientists identified the plaque-like buildup of amyloid beta proteins in brain tissue that causes nerve damage and can lead to symptoms like memory loss, personality changes, and physical debility.

Now, researchers are learning why amyloid beta tends to collect in brain tissue like barnacles on a ship. It might not be rallying expressly to cause damage, but to protect the brain from another invader: the herpes simplex virus.

As The Atlantic recently noted, a number of studies have strengthened the notion that amyloid beta activity is working in response to herpes, the virus that travels along nerve pathways and typically causes cold sores around the mouth (HSV-1) or genitals (HSV-2). In a study involving mice, those engineered to produce more amyloid beta were more resistant to the herpes virus than those who were not.

But when too much amyloid beta is produced to combat the virus, the proteins can affect the brain’s neurons. And while herpes tends to target specific pathways in the body that result in external sores, it’s possible that the virus might act differently in an older population that is susceptible to more widespread infection. Roughly half of adults under age 50 in the U.S. are infected with HSV-1 and 12 percent with HSV-2, which suggests that a large swath of the population could be vulnerable to Alzheimer's disease. Two other strains of the virus, HHV-6A and HHV-7, have also been found to be more common in the brains of deceased Alzheimer’s patients than in the general population.

More research will be needed to further understand the possible relationship between the two. If more findings support the theory, then it’s possible that antiviral drugs or vaccines targeting herpes might also reduce the chances of amyloid beta buildup.

[h/t Atlantic]


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