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

August 24, 2023

Stem cell breakthrough for regenerating lungs

A major proof-of-principle study in mice at Boston University and Boston Medical Center shows it may be possible to treat lung diseases like chronic obstructive pulmonary disease by reconstituting the lungs with stem cells. The study, done in mice, shows that it’s possible to reconstruct lung tissue from cultured mouse or human embryonic stem cells. The researchers cultured progenitor cells and transplanted them into the lungs of mice and showed they differentiate into cells identical to those that line the inner walls of our airways, helping to maintain the integrity of our lungs. The new cells successfully grafted, and once in place they differentiated into mature lung cells that are functionally the same as the existing mature lung cells—a first step toward future cell-based therapies for lung airway diseases. Cell Stem Cell

Do Mediterranean diets and mindfulness make better babies?

In 2017, doctors at the Hospital Sant Joan de Déu and the University of Barcelona began recruiting into a randomized clinical trial 626 mothers who were at high risk of delivering a low-birth weight baby. A third were given free walnuts and olive oil and instructed to follow a structured Mediterranean diet. Another third received training in mindfulness-based stress reduction. And the final third—the control group—received no special instructions. Two years later, the Improving Mothers for a Better Prenatal Care Trial Barcelona (IMPACT BCN) showed the difference on a standard test called the Bayley Scales of Infant and Toddler Development. At 24 months, the babies of women who followed the Mediterranean diet scored higher in both the cognitive and the social-emotional domains, while the children of women who took the mindfulness training had higher scores in the social-emotional domain. What would happen if you did both, we wonder? JAMA Network Open

Enough about X—what about Y?

Two studies this week have filled one final gap in our knowledge of the human genome: the elusive Y chromosome. This male sex chromosome long resisted being fenced in because it is filled with complicated palindromes, tandem repeats, and other sequences that have stymied efforts to sequence it. The first paper fixed that. Produced from the Telomere-to-Telomere (T2T) consortium and led by researchers at the National Human Genome Research Institute in Bethesda, Maryland, Masaryk University in Brno, Czech Republic, the University of California Santa Cruz, the University of Connecticut, and Johns Hopkins University in Baltimore, it presents a complete, 62-million base pair Y chromosome. That’s an important starting point for understanding Y-linked human traits. The second study, led by researchers at Jackson Laboratory for Genomic Medicine in Farmington, Connecticut, and at Clemson University in Greenwood, South Carolina, compared 42 different Y chromosomes taken from individuals spanning 183,000 years of human evolution. That study found considerable diversity in size and structure of the chromosomes and called this discovery “a long-awaited yet crucial milestone towards understanding the full extent of human genetic variation.” Nature

Direct-to-consumer fertility tests not ready for prime time

While we generally encourage the movement of simple procedures and tests out of the doctor’s office and into the consumer marketplace, we only do so when the information offered to consumers is clear and true. Over the counter anti-Mullerian hormone (AMH) tests appear to not fit the bill. Looking at 27 websites across seven different countries that sell a simple blood test to detect AMH levels in a woman’s body—levels that correspond to her egg count—doctors at the University of Sydney in Australia discovered a worrying marketing trend. Analyzing the content on these sales sites, the doctors found that the amount and type of information they offered to consumers was “highly varied.” Troublingly, most made claims about their tests in statements that were not supported by evidence—including false statements that the tests can reliably predict fertility potential or the age of menopause (neither is true—for instance, AMH levels can measure the size of a woman’s egg reserve, but it says nothing about the health of those eggs). “These findings suggest false claims about the AMH test are common, misleading consumers to purchase an AMH test in the belief that it can predict current or future fertility, which may lead to misplaced anxiety or reassurance about one’s fertility,” they write. JAMA Network Open

The secret to sexual pleasure

People who have an extremely rare genetic trait that deactivates PIEZO2—a mechano-sensory protein found on sensory neurons that innervate the skin—have an unusual insensitivity to touch. It turns out they cannot feel light, sexually stimulating touch to their genitals, and they experience no direct pleasure from such stimulations. According to researchers at the National Center for Complementary and Integrative Health in Bethesda, that makes this protein critical for controlling reproduction. It gives mice, humans, and other mammals “exquisite awareness” of their genitals, feeding their arousal and transducing sensual touch into electrical signals to the brain (to which the brain responds, “Don’t stop!”). Male mice cannot have erections without functioning PIEZO2—something they demonstrated experimentally. They also showed that when a colony of 10 male and female mice were genetically altered to remove this protein, then housed together for six months and allowed to mate freely, they never had any pups. A separate colony of normal, wild-type mice allowed to mate freely had a total of 61 rounds of offspring in 180 days. Understanding the function of this ion channel could inform future approaches to treating sexual dysfunction. Science