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Blocking AhR Sensor Activates Regenerative Program in Injured Neurons

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A molecular switch in neurons regulates the regrowth of damaged axonal fibers. This is according to findings in mice, published in a new Nature paper titled “AhR inhibition promotes axon regeneration via a stress–growth switch, that show that blocking a protein called the aryl hydrocarbon receptor (AhR) may help neural regeneration and restore function after injuries to the peripheral nerves or spinal cords. The work is led by a team of scientists from the Icahn School of Medicine at Mount Sinai and their collaborators at other institutions. 

It is an important piece to the puzzle of why neurons in adult mammals have a limited ability to regrow damaged axonal connections. Because of this limitation, injuries to the nerves or spinal cord often result in permanent loss of movement or sensation. “When neurons are injured, they must deal with stress while also trying to regrow their axons,” explained Hongyan Zou, MD, PhD, a professor of neurosurgery, and neuroscience, at the Icahn School of Medicine at Mount Sinai and the study’s senior author. AhR, which was originally identified as a xenobiotic sensor that detects environmental toxins and pollutants, appears to integrate environmental sensing and regenerative capabilities to regrow axons after injury. 

As the scientists explain in Nature, “our work establishes AhR as a brake on axon regeneration that integrates transcriptional, metabolic and epigenetic programs to enforce proteostasis at the expense of regenerative growth.” Basically it “functions like a brake that shifts neurons toward managing stress rather than rebuilding damaged connections,” Zou said. 

According to results reported in the paper, the team found that when AhR signaling is active, axon growth slows. But when the protein is removed from neurons or has its signaling activity blocked with drugs, axonal fibers grew more effectively. In fact, in mouse models of peripheral nerve injury and spinal cord injury, inhibiting AhR also improved recovery of motor and sensory function, the scientists wrote. 

More detailed experiments helped elucidate how the process works. Following injury or stress, AhR helps neurons cope by maintaining proteostasis and reducing the protein production needed for growth. When it is turned off, neurons adopt a new protection strategy. They begin producing more protein and activate growth-related pathways that support axon regeneration. The growth process is also supported by HIF-1α, which helps regulate genes involved in metabolism and tissue repair. 

These results point to some possible treatment directions for spinal cord injury, stroke, or other neurological diseases. Several drugs that block AhR are already being tested in clinical trials for other diseases, and they could eventually be studied in this context as well. However, more research is needed before this approach can be trialed in patients, the scientists said. 

Future studies will examine how effective AhR inhibitors are in different types of neural damage, determine the best timing and dosage for treatment, and assess the impact of these treatments on other cells after injury. As part of their next steps, the Mount Sinai team plans to test AhR-blocking drugs and gene-therapy strategies designed to reduce the protein’s activity in neurons. 

The post Blocking AhR Sensor Activates Regenerative Program in Injured Neurons appeared first on GEN – Genetic Engineering and Biotechnology News.

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Opinion: STAT+: Former Geisinger CEO: U.S. health systems must replace huge numbers of people with AI 

About 20 years ago, I stepped on stage at one of our Geisinger town halls and looked out upon a sea of people: thousands of full-time employees at an integrated health system charged with the health and well-being of millions of Pennsylvanians. 

Only a fraction of the people in that room were clinicians. 

That was the first time I fully visualized the problem: We employed more people in our revenue cycle department to process bills and reconcile data than we did doctors. And we weren’t alone. It’s the same story at every health system in America, large and small, and over the past two decades, the ratio has become dramatically more disparate. 

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About 20 years ago, I stepped on stage at one of our Geisinger town halls and looked out upon a sea of people: thousands of full-time employees at an integrated health system charged with the health and well-being of millions of Pennsylvanians. 

Only a fraction of the people in that room were clinicians. 

That was the first time I fully visualized the problem: We employed more people in our revenue cycle department to process bills and reconcile data than we did doctors. And we weren’t alone. It’s the same story at every health system in America, large and small, and over the past two decades, the ratio has become dramatically more disparate. 

Continue to STAT+ to read the full story…

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Microplastics in Human Bile Drive Mitochondrial Dysfunction and Senescence

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Microplastics have become a defining environmental signature of modern life, turning up in oceans, soil, food, drinking water, and even the air. But their biological fate inside the human body remains far less understood. A new study suggests that these particles may be doing more than simply passing through. Instead, they may be accumulating in one of the body’s most overlooked fluids—bile—and leaving behind measurable cellular damage that could shape future thinking about environmentally driven biliary injury and long‑term health effects. As the authors noted in their abstract, “the long-term accumulation patterns and chronic toxic effects of microplastics within the human biliary system are largely unknown,” underscoring the need for deeper investigation into how these particles behave in the enterohepatic circulation.

Researchers from the Tenth Affiliated Hospital of Southern Medical University (Dongguan People’s Hospital), Sun Yat-sen University, Guilin Medical University, and collaborating institutions reported the findings in Environmental Science and Ecotechnology. Their study, “Microplastics accumulate in human bile and drive cholangiocyte senescence,” provides the first direct evidence that microplastics are not only present in bile but may also contribute to mitochondrial dysfunction and premature aging in cholangiocytes, the epithelial cells that line the bile ducts.

The team collected bile from 14 surgical patients (five without gallstones and nine with gallstones) and used a multimodal analytical approach—pyrolysis–gas chromatography–mass spectrometry, laser direct infrared spectroscopy, and scanning electron microscopy—to characterize the particles. According to the paper, “we show the universal presence of microplastics in human bile,” identifying six polymer types dominated by polyethylene terephthalate and polyethylene, with most particles measuring 20–50 μm. Patients with gallstones carried substantially higher microplastic burdens, raising questions about whether biliary stasis or altered bile composition may influence microplastic retention.

bile and microplastics study
This schematic summarizes the study workflow and main findings. Human exposure to microplastics may occur through multiple routes, including industrial pollution, airborne exposure, food packaging, drinking-related plastics, and consumer products. Bile samples collected from individuals with and without gallstones were analyzed using Py-GC/MS, LDIR, and SEM, which confirmed the presence, polymer composition, particle size, and morphology of microplastics in human bile. Mechanistic experiments further showed that nanoplastic exposure induced cholangiocyte senescence by triggering mitochondrial dysfunction, including increased mitochondrial reactive oxygen species, enhanced Drp1-mediated fission, reduced mitochondrial membrane potential, and decreased ATP production, while melatonin partially alleviated these toxic effects. [Environmental Science and Ecotechnology]

To probe biological effects, the researchers exposed cultured human cholangiocytes to low-dose polystyrene nanoplastics for seven days, simulating chronic exposure. The cells exhibited mitochondrial dysfunction, elevated reactive oxygen species, reduced ATP, Drp1‑mediated mitochondrial fission, and G1 cell‑cycle arrest—hallmarks of senescence. As the authors wrote, chronic exposure “induces mitochondrial dysfunction-associated senescence in cholangiocytes,” suggesting a mechanistic link between environmental microplastics and biliary aging.

One of the most intriguing findings is that melatonin, a widely used antioxidant, partially reversed the mitochondrial and inflammatory damage. While far from a therapeutic recommendation, the result hints at a potential intervention point and gives the study translational relevance.

The work reframes the biliary system as something far more active than a simple transit channel. The data indicate that bile can serve as a reservoir for microplastics and that prolonged exposure may age cholangiocytes by driving mitochondrial dysfunction. The partial rescue with melatonin adds a mechanistic foothold for future intervention, even as the authors caution that broader human studies are essential.

For biotech, the implications are broad. The work highlights bile as a clinically accessible matrix for exposure assessment, opening the door to new diagnostics for environmental toxicology. The mitochondrial stress signature aligns with pathways already being targeted by companies developing senolytics, mitoprotective agents, and anti‑inflammatory therapeutics. The authors wrote that the research provides “a mechanistic foundation for assessing the health risks of plastic pollution and developing therapeutic interventions for environmentally driven biliary disorders.”

The post Microplastics in Human Bile Drive Mitochondrial Dysfunction and Senescence appeared first on GEN – Genetic Engineering and Biotechnology News.

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STAT+: Health insurers score major win with higher 2027 Medicare Advantage rates

Companies that sell Medicare Advantage plans will receive a 2.5% pay bump on average in 2027, up significantly from what was proposed and a win for an industry that has experienced higher medical costs and has opposed nearly all reforms to the lucrative taxpayer-financed program.

More importantly, the Trump administration scrapped its proposal that would have used more updated data in the payment process, ensuring that Medicare Advantage insurers retain billions of dollars.

In addition to base payments, Medicare Advantage insurers get paid based on how sick their members. This process is known as risk adjustment and has been flagged by watchdogs, auditors, and federal attorneys as rife with abuse. Trump officials proposed using newer data that goes into seniors’ “risk scores,” but after intense industry pushback over the past two months, they are dropping the proposal for now. 

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Companies that sell Medicare Advantage plans will receive a 2.5% pay bump on average in 2027, up significantly from what was proposed and a win for an industry that has experienced higher medical costs and has opposed nearly all reforms to the lucrative taxpayer-financed program.

More importantly, the Trump administration scrapped its proposal that would have used more updated data in the payment process, ensuring that Medicare Advantage insurers retain billions of dollars.

In addition to base payments, Medicare Advantage insurers get paid based on how sick their members. This process is known as risk adjustment and has been flagged by watchdogs, auditors, and federal attorneys as rife with abuse. Trump officials proposed using newer data that goes into seniors’ “risk scores,” but after intense industry pushback over the past two months, they are dropping the proposal for now. 

Continue to STAT+ to read the full story…

Read More

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