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

March 31, 2022

Metformin associated with major birth defects

A large study in Denmark of 1,116,779 babies born from 1997–2016 found a higher risk of major genital birth defects among boys whose fathers while trying to conceive filled at least one prescription for metformin—a type 2 diabetes drug that also fills hope chests in longevity circles and is being clinically tested for extending lifespan and healthspan. The new research may not affect those longevity prospects, but the results demonstrate how the drug impacts male reproduction, and the authors suggest men who are trying to conceive while on metformin should talk to their doctors. Annals of Internal Medicine

Video game shows how urban design influences our ability to navigate

A new study from the University of Lyon in France and University College London looking at the impact of urban design on cognition shows that the layout of city streets where we grow up impacts how well we can navigate unfamiliar landscapes. The researcher examined how 397,162 people from 38 countries navigated different virtual environments in video game Sea Hero Quest and found people who grew up in grid-like urban areas like Chicago with low “street network entropy” are better at finding their way through more orderly video game layouts, and conversely people are better at navigating video game terrains with more chaotic layouts if they were raised in places like Prague, where even the cabbies get lost. Nature

Street networks of different griddy and entropic cities. Created by Antoine Coutrot and Ed Manley

Neuropathic pain linked to action of microglial cells in mice

Chronic neuropathic pain comes from damage to peripheral somatosensory nerves due to things like infections, injuries, diabetes, autoimmunity, or amputations. It’s a major problem because neuropathic pain often doesn’t respond to standard treatment, it may get worse over time, and it can be debilitating. Now researchers at Kyushu University in Fukuoka, Japan, have uncovered the involvement of a type of immune cell known as CD11c-expressing spinal microglia in this type of pain. They showed that nerve-injured mice lacking these cells were hypersensitive to pain and that blocking signals from the microglia in normal mice induced pain hypersensitivity. “Our findings reveal a mechanism for the remission and recurrence of neuropathic pain, providing potential targets for therapeutic strategies,” the authors write. Science

If you want to find life on other planets, look for the gas

The $10 billion NASA James Webb telescope launched last year with the promise of becoming the most powerful eye ever to gaze out at the Universe. Among the things it will look for are exoplanets, including ones that could potentially be biologically rich future homes for humanity. But how will we tell the difference between a warm, welcoming planet that’s teeming with life and a starkly barren hunk of rock? Some point to methane, a greenhouse gas associated with life found in everything from swamp gas to cow farts. But there are lots of non-biological sources of methane—including volcanoes, deep sea vents, and asteroid impacts. So how do you rule out false positives? Researchers at the University of California, Santa Cruz have proposed a new framework for assessing atmospheric methane, which they write could help methane become “the first detectable indication of life beyond Earth.” PNAS

Known sources of methane on Earth that are not associated with biology include volcanoes, mid-ocean ridges, hydrothermal vents, subduction zones, and asteroid impacts. © 2022 Elena Hartley

Generosity in times of pandemic

One big silver lining to all the fear, uncertainty, and tragic loss Americans endured during the coronavirus pandemic is this: People apparently became more generous. Looking at a four-year dataset compiled by Charity Navigator of 696,942 monetary donations made before and during the pandemic, researchers at the University of California, San Diego found charitable giving increased in U.S. counties when they were facing COVID-19 threats. The idea that people under threat become more generous toward others is a concept social scientists call “catastrophe compassion,” and the new research suggests it was strongly present during the pandemic—despite all the toilet paper hoarding and early predictions that the severe economic downturn experienced during COVID-19 would lead to reduced giving. Scientific Reports