The genetics of aging are puzzling if you look comparatively at different mammals. Some species live long lives measured in centuries while others take but a short drink of worldly existence, dying of old age in just a few dozen months. This gerodivergence is all the more perplexing when you consider mammals all basically carry approximately the same set of highly similar genes. But a picture emerges that begins to make more sense when you consider how and when those genes are expressed. In recent years, tools like the “Horvath clock” have emerged to measure age-related “epigenetic” chemical modification of genes, which controls their timing of expression. Now a major study from University of California, Los Angeles and Altos Labs in San Diego has uncovered how epigenetic modification varies globally. Looking at the methylation patterns of 15,000 mammals belonging to 348 species, from the mighty African elephant to the lowly lab rat, the researchers found strikingly different DNA methylation profiles among them. These patterns parallel genetic divergence in evolution, leading the authors to conclude, “DNA methylation is subjected to evolutionary pressures and selection.” Science

Sometimes the conclusion of a scientific study seems so obvious that we have to ask, Really?! Such was the case this week after reading a study from Mie University in Tsu, Japan. Seeking to identify trends and factors associated with suicide mortality and motives among 12,396 middle-school, high-school, and university-level students in Japan from 2007–2022, the study found changes in mortality differed among these different age cohorts and between boys and girls. The researchers say what drives these differences is the simple fact that what motivates a kid to attempt suicide differs by gender and changes as they undergo psychosocial development—spending less time with their parents and more time with their peers as they age, for instance. They conclude that rather than applying the lessons of adolescent research in a one-size-fits-all way, effective school-based suicide prevention programs should be designed specifically to the vulnerabilities of each developmental stage and gender. JAMA Network Open

In a small study of 56 infants aged 4–6 months, the levels of certain gut microbes were linked to their performance on cognitive tests. Taking fecal samples of the infants, researchers at the University of British Columbia compared their microbiomes to standard cognitive evaluations. They found infants who succeeded at the “point and gaze” test of social attention tended to have increased Actinobacteria, Bifidobacterium, and Eggerthella bacteria as well as reduced Firmicutes, Hungatella, and Streptococcus bacteria. Performance on another test, called neural rhythm tracking, was negatively associated with Bifidobacterium abundance, however, and positively linked to the abundance of Clostridium and Enterococcus bacteria. “Although the tests were under-powered due to the small pilot sample sizes, potential associations were identified between the microbiome and measurements of early cognitive development that are worth exploring further,” the researchers write. PLOS ONE

An infant listening to a rhythmic pattern while their brain responses are measured via EEG. Auditory Development Lab, McMaster University, CC-BY 4.0

Researchers at Zhejiang University in Hangzhou, China, have found an unexpected association between air quality and antimicrobial resistance, which causes an estimated 1.27 million premature deaths each year and is identified by the World Health Organization as one of the top 10 threats to global health. The new study looked at PM2.5 fine particle air pollution (particulate matter measuring 2.5 microns) and collected air quality samples as well as antimicrobial infection numbers and other data from 2000–2018 in 116 countries. The researchers found significant correlations between PM2.5 and the presence of drug-resistant bacteria globally, and they estimate antibiotic resistance linked to air pollution caused nearly 500,000 premature deaths—and $395 billion in economic losses—in 2018 alone. Improving air quality to meet WHO’s 2050 goals, they write, would reduce global antibiotic resistance by 16.8 percent, spare nearly a quarter of those premature deaths every year, and save world economies some $640 billion annually. The Lancet Planetary Health

Age-related muscle loss, a condition known as sarcopenia, is poorly defined, misunderstood, inadequately treated, and very, very common all at the same time. Despite a number of attempts to develop drugs, there are no approved therapeutics currently available for people with sarcopenia. New research by scientists from Daegu Gyeongbuk Institute of Science and Technology and the company CTCELLS in Daegu, South Korea could change that, however. Unveiling what they call “silver electroceutical technology,” researchers designed a personalized medicine approach that relies on optimizing electrical stimulation for age and physiology. They tested its potential to treat sarcopenia and recover skeletal muscle in mice. “Electroceutical treatment for sarcopenia has good prospects for clinical application,” they conclude. PNAS

Researchers at the University of California, San Diego, the University of Adelaide, the Colonoscopy Clinic, Brisbane, and the South Australia Health and Medical Research Institute have developed a cell-based biosensor to detect the presence of colorectal cancer cells and tumors in the body. They used synthetic biology to engineer designer cells of the bacterium Acinetobacter baylyi, which is known to sample DNA from its environment. They engineered their new cells to detect mutated KRAS genes, which are an important driver of colorectal cancer growth, and they tested their cells in mice with colorectal tumors. Though they say the technology is not yet ready for clinical application, they envision it could one day be used to sample the digestive tract directly for signs of cancer. Science

Is there room for yet another Hollywood treatment of the opioid epidemic? The answer, in Netflix’s new six-part miniseries Painkiller, is a resounding yes. Deftly directed by Peter Berg (Patriots Day, Deepwater Horizon) and based on a book of the same name by former New York Times reporter Barry Meier and a New Yorker article by Patrick Radden Keefe, the series visits our awful modern crisis with both high-flying imaginative flair and a hard-hitting, almost documentary-style grounding. It parallels the righteous anger of a justice-seeking investigator played by Uzo Aduba (Orange Is the New Black) with the alternatively duplicitous and soul-searching moves of two young female Purdue Pharma sales reps played by newcomers Dina Shihabi and West Duchovny (yes, that Duchovny). Perhaps the best performance, however, is delivered by 1980s icon Matthew Broderick (WarGames, Ferris Bueller’s Day Off), who portrays the seemingly soulless Purdue executive Richard Sackler to masterful effect. Also compelling is the tough-guy character played by Taylor Kitsch (True Detective, Friday Night Lights), an ordinary American who gets injured, prescribed large amounts of OxyContin, and soon suffers the throes of full-blown addiction. Premiers August 10 on Netflix

Matthew Broderick, center, in a still from the new Netflix series Painkiller portraying Richard Sackler marketing the drug OxyContin.

Meanwhile, a new study looking at peppermint oil for pain management could help people with post-operative pain. Doctors at Kashan University of Medical Sciences in Iran enrolled 64 adults who had just had open-heart surgery in a small clinical trial. They randomized the people into two groups, half of whom were given peppermint oil aromatherapy in their breathing tubes and then told to use a nebulizer with the scent for two more days after the breathing tube was removed. The people who received the peppermint reported less pain, needed to take fewer drugs for pain relief, and slept better during that time than people who got a placebo with no essential oils. It can be that simple. BMJ Supportive & Palliative Care