The week’s most astounding developments from the neobiological frontier.

April 6, 2023

Probiotic boosts the effectiveness of cancer checkpoint inhibitors

In the last decade, emerging cancer therapies known as immune checkpoint inhibitors have saved countless lives, but are ineffective in many. Only 40 percent of people with melanoma respond to the treatment, for instance. There’s some evidence that dietary interventions focused on a person’s microbiome can boost the efficacy of checkpoint inhibitors, and many people are now preemptively taking probiotics along with therapy, but the science is unclear. Now researchers at the University of Pittsburgh School of Medicine have discovered that the probiotic bacterium Lactobacillus reuteri colonizes tumors and releases a metabolite known as tryptophan catabolite I3A, which attracts killer T cells—an insight that may help more people respond to immune checkpoint inhibitor therapy and survive cancer. Cell

Vaccinating pregnant mothers to protect children after birth

A new phase 3 double-blind clinical trial conducted in 18 countries by Pfizer shows babies can be protected against the deadly viral infection RSV during their first year of life by vaccinating their pregnant mothers. Dubbed the Maternal Immunization Study for Safety and Efficacy (MATISSE), the trial tested the protective effect on babies of the RSV vaccine given to 3,682 women at 24–36 weeks of gestation compared to 3,676 controls. The study found the vaccine was 81.8 percent effective within 90 days after birth, though the protection dropped to around 70 percent by 180 days. No safety concerns were detected in the infants or mothers in the trial. New England Journal of Medicine

Centenarians have young looking gut microbiomes

Scientists at the Guangxi Academy of Sciences in Nanning, China, and the Chinese Academy of Agricultural Sciences in Lanzhou have discovered that people who live past 100 years are not so much young-at-heart as they are young-at-gut. Examining the biology of 1,575 people from Guangxi province of China aged 20–117 (including 297 centenarians), they found the centenarians had gut compositions that looked more like youthful microbiomes—more diverse, enriched for beneficial Bacteroidetes bacteria, and depleted of pro-inflammatory bacteria. These characteristics “may confer positive effects on their health by reducing the senescence or chronic diseases that generally accompany aging,” they write. Nature Aging

Ecologists tap into elders’ wisdom

Years of fruitless research involving remote sensing, satellite aerial images, and heavy-duty number crunching failed to uncover the origins of so-called “fairy circles”—regularly spaced, perfectly circular bare patches in the arid grasslands of Australian deserts. Scientists thought they may be due to plant self-organization—maybe? But it’s far less of a mystery than assumed. The circles are pavement nests left by Drepanotermes harvester termites, and knowledge of that fact has been hard baked into the Australian Aboriginal art and language of the Manyjilyjarra and Warlpiri peoples, who have long used the insects for food and sacred purposes, for thousands of years. A collaboration between ecologists at the University of Western Australia and Warlpiri elders uncovered the truth of the fairy circles and points to the fruitfulness of such partnerships. “First Peoples and their knowledge are critical to improving ecosystem studies and ecosystem management,” the authors write. Nature Ecology & Evolution

Left: A typical circle. Right: Painting “Flying termite dreaming” by Anmatyerre Warlpiri man (1980). Photo by Fiona Walsh. Painting published CC-BY-NC-ND by Papunya Tula Artists and Aboriginal Artists Agency.

Antimicrobial resistance goes farm to table as well as bedside to trough

The looming global health specter of antimicrobial resistance has long been associated with the over prescription and inappropriate prescription of antibiotic drugs in human populations. However, farm animals are often fed antibiotics as well, which is seen as a related public health issue—though researchers at the London School of Hygiene & Tropical Medicine are suggesting this week that the two problems are one and the same. They found there is a bi-directional risk of antimicrobial resistance between humans and animals: Greater consumption of antibiotics by animals drives increased risk of resistance in human pathogens and vice-versa. In some places, the risk of antimicrobial resistance in humans may be driven predominantly by agricultural antibiotic use, which suggests the need for better monitoring and tools to prevent the transmission of resistance between humans and animals. The Lancet Planetary Health

Pluripotent stem cells—where are the studies, and who is paying for them?

Anyone interested in the history and current state-of-the-art of the business and science of stem cell transplantation will find a new perspective by researchers at the Fraunhofer Institute for Biomedical Engineering (IBMT) in Sulzbach, Germany, to be required reading. It shows how in the last five years induced pluripotent stem cells have come to dominate research, surpassing studies involving the controversial use of human embryonic stem cells. The paper also reveals that while clinical studies involving pluripotent stem cells have been conducted in 14 countries in the last half decade, three countries dominate the academic research and commercial development—the United States, China, and Japan. The article also reveals increased industry sponsorship for these studies. Stem Cell Reports

Clinical studies using embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), somatic cell nuclear transfer (SCNT) cells, and parthenotic pluripotent stem cells (pPSCs) from 2011–2022.

Improving stem cell transplants

Doctors at Massachusetts General Hospital in Boston have shown that an FDA-approved leukemia drug called venetoclax can increase tolerance for stem cell transplants and kidney transplants in large animals. The use of hematopoietic stem cell transplantation to treat autoimmune diseases and other indications is somewhat hampered by the need to deplete host stem cells before the treatment with irradiation or chemotherapeutic drugs. But the Boston doctors showed that they could improve tolerance for stem cell grafts while cutting the amount of radiation in half by combining it with the drug. Science Translational Medicine

You can’t fool me—I have no thumbs!

Smart social animals, like humans and monkeys, can anticipate actions during interpersonal interactions. But magicians, mentalists, gamblers, and wizards have long exploited this fundamental mental trait for their tricks, cheats, and illusions. Sleight of hand and the old disappearing coin trick relies on misdirecting an audience’s attention by partially covering the thumb then palming the object. The audience incorrectly anticipates what the thumb is doing even though they can’t see it—thus the magic. Curiously, psychologists at the National University of Singapore and the University of Cambridge have discovered that you need thumbs to be fooled by this illusion. They tested sleight of hand with tasty treats like peanuts and mealworms on 24 monkeys. Humboldt’s squirrel monkeys and yellow-breasted capuchins, which both have thumbs, were fooled 81 and 93 percent of the time. But the common marmosets Callithrix jacchus, which has no thumbs, fell for it far less—only 6 percent of the time. Current Biology

Three species of New World monkey with inherently different hand anatomy and biomechanical ability. (L to R) The yellow-breasted capuchins (Sapajus xanthosternos) and squirrel monkeys (Saimiri sciureus) are fooled by sleight of hand, while common marmosets (Callithrix jacchus) are not. CC images