Plate Nº 91 · recorded October 10, 2026
Health & Medicine ResearchReported finding
Aging Muscle Weakness Linked to Failing Nerve Connection
University of Missouri researchers linked age-related muscle weakness to a breakdown in nerve-to-muscle signaling driven by loss of the NaV1.4 protein. Partially blocking ClC-1 restored strength in mice.
By Priya Raman3 min read624 words
In brief
- Sarcopenia affects nearly half of adults older than 80, according to the researchers.
- The study was published on September 24, 2026 in The Journal of Clinical Investigation (DOI: 10.1172/JCI190646).
- Reduced levels of the NaV1.4 protein weakened how muscle fibers responded to nerve signals in both human tissue and mice.
- Partially blocking the ClC-1 protein increased muscle strength in an animal model.
- NMD Pharma's experimental drug ignaseclant, which targets ClC-1, has already been tested in patients with Charcot-Marie-Tooth disease.
Researchers at the University of Missouri-Columbia reported on September 24, 2026 that communication between nerves and muscles becomes unreliable with age, offering a new explanation for sarcopenia, the muscle decline that affects nearly half of adults older than 80.
The team, led by W. David Arnold, executive director of the NextGen Precision Health initiative, tied the problem to lower levels of a protein called NaV1.4, which helps muscle fibers respond to nerve signals. In animal tests, partially blocking a second protein, ClC-1, restored some of the lost strength.
What did scientists previously think caused muscle weakness?
For decades, research on age-related muscle loss focused on two suspects: the gradual shrinking of muscle tissue and the death of motor neurons that activate muscles. Arnold suspected a third problem sat at the junction between them — the neuromuscular junction, the contact point where a nerve fires an electrical signal that triggers a muscle to contract.
Under healthy conditions, that junction transmits with extreme reliability. The new study, published in The Journal of Clinical Investigation, shows that reliability falls as people age. Human tissue samples and mouse models both showed fewer NaV1.4 channels at the junction, weakening the muscle's response.
"A long-held assumption in the field was that the neuromuscular junction remains reliable during aging, and some even suggested it may get better with aging," Arnold said. "The significance of this new study is we are showing, in both humans and in animal models, that the neuromuscular junction is failing with aging."
How might the discovery lead to treatment?
The finding points to a target that drugs can address. Working with NMD Pharma, a biotechnology company based in Denmark, the team used a compound that partially inhibits ClC-1, a chloride channel that appears to dampen the muscle's response to incoming nerve signals when overactive. Blocking part of ClC-1 made aging muscles more responsive and increased their strength in mice.
"We identified an important point of failure at the final step in communication between nerves and muscles," Arnold said. "And what is perhaps even more exciting is that we showed this failure is potentially reversible."
The approach does not aim to replace lost muscle or neurons. Instead, it tries to make existing muscle fibers more responsive to the messages they already receive.
Is a drug already available to test in people?
NMD Pharma has advanced an experimental drug called ignaseclant that partially blocks ClC-1. Arnold served as an investigator in a multicenter clinical trial of ignaseclant in patients with Charcot-Marie-Tooth disease, the most common inherited neuromuscular disorder. That trial reported improvements across several measures of muscle strength and physical function. Arnold presented the topline results at the 2026 Muscular Dystrophy Association Clinical & Scientific Conference.
Those trials addressed a different condition, not age-related muscle loss. Arnold said he hopes ignaseclant can eventually move into studies of older adults with sarcopenia.
What comes next?
Arnold's group pulls together collaborators from Denmark, Scotland, Saudi Arabia and India. At Mizzou, the team has also recruited Hiroshi Nishimune, a co-author of the new study who moved to Columbia from Tokyo to lead imaging work on the neuromuscular junction.
"While the human lifespan has increased in recent decades, our ultimate goal at Mizzou is to ensure a person's health span remains as high as possible for as long as possible," Arnold said.
The study, "Neuromuscular junction failure in sarcopenia is linked to NaV1.4 loss and reversed by ClC-1 inhibition," appears in the September 24, 2026 issue of The Journal of Clinical Investigation (DOI: 10.1172/JCI190646). Results in animal models do not always carry over to humans, and any sarcopenia treatment will require additional clinical trials.
via showme.missouri.edu (Original)
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Senior reporter covering industry trends and analytics at SciBeat.
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