In what some are calling the first systematic, worldwide catalog of microbes in urban environments, a global consortium of researchers sequenced DNA from 4,728 samples collected in 2015–2017 from swabbing ticket counters, benches, rails, and other commonly touched surfaces in the mass transit systems of 60 cities around the world. The results show a surprising, previously unseen urban landscape filled with 10,928 viruses, 1,302 bacteria, and 2 archaea—half of them previously unknown to science. What’s more, the study found that across the world, cities possess a consistent core set of 31 “urban” microbes, present in 97 percent of all samples, as well as geographic variations across cities. It also identified microbial signatures specific to each city that could predict where any one sample came from, and in a troubling result, found evidence that antimicrobial resistance genes were widespread in cities. Cell
The power of the narrative was on display in a new clinical study published this week involving 81 children in Brazil. Separately enrolled while awaiting treatment at a Brazilian ICU, the children were paired either with an adult who helped pass the time by asking them riddles or a professional storyteller who told tales of fantastic worlds filled with imaginary characters. Half an hour later, all the children were given psychological tasks to perform that gauged their emotional states, and their saliva was tested for biomarkers. The children who heard stories showed more positive emotional shifts, an increase in oxytocin, and reductions in cortisol and pain than the ones tasked with solving riddles—suggesting that simple storytelling could be a low-cost intervention for improving the wellbeing of hospitalized children. PNAS
The long expected update of the International Society for Stem Cell Research to its touchstone Guidelines for Stem Cell Research and Clinical Translation has landed this week. Last revised in 2016, the new 2021 guidelines cover advances including the use of stem cells in embryo models, human embryo research, the development of chimeras, the creation of organoids, genome editing, and ethical, social, and policy implications. The most significant change to the guidance was relaxing the two-week limit on how long intact human embryos could be cultured in the laboratory before they must be destroyed—the so-called “14-day rule.” The new guidelines call for permitting research beyond 14 days with sufficient opportunity for public input and the prior approval of an oversight body. Stem Cell Reports
We already know that cuddling helps babies form secure attachments. Now a practice called “kangaroo care,” which involves continuous skin-to-skin contact between an infant and mother or other caregiver for many hours a day, was shown to actually save the lives of low-birth-weight infants in a clinical trial. It could be a low-cost, highly effective intervention for saving countless more babies’ lives. Researchers at the World Health Organization (WHO) followed 3,211 infants born weighing less than 2 kilograms in Ghana, India, Malawi, Nigeria, and Tanzania. Half were treated with the standard methods for caring for low-birth-weight infants, which involves incubators and radiant warmers. The other half received kangaroo care from within a couple hours of birth. They were held in close skin-to-skin contact for a median of 16.9 hours of per day, and at 28 days, they had a 25 percent greater chance of surviving than the babies in the other group, among other more favorable health outcomes. The results were so favorable the trial was stopped early on the recommendation of the data and safety monitoring board. NEJM
The race is on to find the key metric we want to use to track how well or how poorly we’re aging. Some swear by the idea of looking at DNA methylation through approaches like the Horvath clock. Now, researchers in Singapore, Moscow, and Buffalo, New York, have analyzed a large database of blood count data and developed a single indicator of aging they call the dynamic organism state indicator (DOSI). When extrapolated, it yields a theoretical maximum lifespan in the range of 100–150 years—end-capped by a loss of resilience late in life. The authors say no dramatic improvement to maximum human lifespan would be possible by preventing or curing diseases alone without also addressing this underlying loss of resilience. The good news: Their indicator may be useful for testing future clinical experiments to test potential life-extending therapies. Nature Communications
A novel approach to treating blindness at Sorbonne University in Paris was able to return partial vision to a 58-year-old man diagnosed 40 years ago with retinitis pigmentosa, an inherited, neurodegenerative form of blindness that strikes more than 2 million people worldwide. Almost no therapeutic options exist for people with retinitis pigmentosa, but in this new approach, doctors gave the man an intraocular injection of an adenovirus vector into retinal ganglion cells in one eye. The virus inserted genes encoding the light-sensing rhodopsin channel protein ChrimsonR fused to a red fluorescent protein. The patient wore a special set of goggles that detected changes in ambient light intensity and projected light pulses onto his retinas in real time. This enabled him to find and touch different objects on a table while wearing the goggles. Nature Medicine
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