Resetting the body clock could help the brain recover after stroke

 Your incompetent? doctor and hospital will fail at doing further research and human testing to change 'could' to will! And I'm sure they didn't create sleep or glymphatic clearance protocols.

• glymphatic clearance (10 posts to June 2022) 
• sleep (242 posts to August 2010)

NOT DOING EITHER ONE IS PURE INCOMPETENCE!

Resetting the body clock could help the brain recover after stroke

 Scientists at the University of Rochester Medicine have found that strengthening the body's natural daily rhythms to improve sleep may help the brain recover after a stroke. The work points to a possible new way to support brain waste clearance and improve recovery well after the initial injury. Published in the Journal of Clinical Investigation, the study showed that interventions designed to reinforce circadian rhythms improved recovery in mouse models of stroke. These improvements were accompanied by stronger activity in the glymphatic system, the brain's waste-clearing network, along with lower levels of inflammatory molecules that can persist after a stroke. 

How the Brain Clears Waste

The findings build on more than a decade of research led by URochester Medicine neuroscientist Maiken Nedergaard, MD, DMSc. Her laboratory discovered the glymphatic system in 2012. This system moves cerebrospinal fluid through the brain, helping remove waste products and other debris. Later studies found that glymphatic activity is especially strong during sleep and plays an important role in maintaining brain health.Neuroscientist Lauren Hablitz, PhD, later helped show that glymphatic activity is influenced not only by sleep, but also by circadian rhythms, the body's internal 24-hour clock. In a landmark 2020 study, Hablitz, Nedergaard, and colleagues demonstrated that glymphatic function follows daily cycles even independently of sleep, establishing a direct link between circadian biology and the brain's waste-clearing system. 

Stroke May Disrupt the Brain's Timing

"The discussion of stroke recovery really starts with the idea that stroke is not just a vascular event, but also a disorder of timing," said Hablitz, lead author of the new study. Scientists have long known that strokes tend to follow distinct time-of-day patterns. They occur more often during the morning and are frequently more severe near the end of the sleep period. After a stroke, many patients also develop disrupted sleep-wake cycles. Those disturbances have been linked with worse recovery, depression, and reduced quality of life. "That led us to ask a simple question," said Hablitz. "If timing is broken after a stroke, can we improve recovery by reinforcing the biological clock?" 

When the Brain's Cleanup System Slows Down

 In a healthy brain, the glymphatic system carries cerebrospinal fluid along blood vessels and through brain tissue. This process delivers nutrients while helping remove waste products and inflammatory signals. Earlier research has shown that glymphatic function becomes impaired after stroke. That disruption may reduce the brain's ability to clear harmful molecules that accumulate during recovery. Stroke research has traditionally focused on separating beneficial inflammation from harmful inflammation and finding ways to suppress the damaging forms. Hablitz and her colleagues suggest that another part of the problem may be that the brain is no longer clearing inflammatory signals effectively. "We think part of the problem may be a failure of cleaning," she said. "If the system responsible for clearing signaling molecules isn't working properly, everything builds up."Under this model, stroke damages both brain tissue and the pathways responsible for removing inflammatory signals. As those molecules accumulate, they may contribute to continued damage and slower recovery. 

Resetting the Body Clock

To test whether stronger circadian rhythms could improve recovery, the researchers examined several interventions known to affect the body's internal clock. These included timed light exposure, melatonin, a clock-targeting drug called KL001, and time-restricted feeding. The team first showed that each of these interventions could improve glymphatic function in healthy animals. They then selected the most promising strategies, KL001 and time-restricted feeding, and tested them in mouse models of stroke. Treatment did not begin until three days after the stroke, far beyond the narrow window used for clot-busting drugs and other acute stroke treatments. Even with that delay, mice that received either intervention showed better motor recovery, smaller lesion volumes, improved glymphatic flow, and lower levels of inflammatory cytokines in the brain. "All of the cytokines moved in the same direction," Hablitz said. "That suggests we may not be targeting one specific inflammatory pathway. Instead, we may be helping the brain clear inflammatory signals more effectively." One of the most promising approaches was time-restricted feeding, a behavioral intervention that is already being investigated for obesity, diabetes, cardiovascular disease, and other conditions. That could make the findings especially relevant for stroke rehabilitation because such an approach might eventually be easier to use outside specialized medical settings. "One of the exciting aspects of this work is that we're studying interventions that could potentially be implemented not only in hospitals but also at home," Hablitz said. 

What Researchers Need to Test Next

 The researchers emphasize that the findings so far are limited to animal models. More studies will be needed to determine exactly how circadian rhythms, glymphatic function, and inflammation influence one another after stroke. Future work will also examine whether improved glymphatic flow directly causes better recovery and whether circadian-based interventions can eventually be tested in clinical trials. More broadly, the study reflects a growing view in neuroscience that sleep, circadian rhythms, and fluid movement through the brain are central to brain health. By learning more about how the brain's internal clock regulates the glymphatic system, researchers hope to uncover new ways to improve recovery not only after stroke, but also in other neurological conditions involving inflammation and poor waste clearance. "Understanding how circadian regulation shapes glymphatic clearance will help us develop more targeted therapies," said Hablitz. "Ultimately, our goal is to find ways to improve the brain's ability to clear waste, reduce inflammation, and recover after injury." Health & Medicine Diabetes Heart Disease Mental Health Research Pharmacology Depression Mental Health Stroke Consumer Behavior RELATED TERMS

• Circadian rhythm sleep disorder
• Hypothalamus
• Circadian rhythm
• Central nervous system
• Human brain
• Limbic system
• Deep brain stimulation
• Spinal cord

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Story Source:

Materials provided by University of Rochester Medical Center. Note: Content may be edited for style and length.

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Journal Reference:

1. Emma Waight, Yuxi Zhu, Ashley Caudell, Velia S. Vizcarra, Evan Newbold, Michael J. Giannetto, Evalien Duyvestyn, Estephanie Balbuena, Wei Song, Tanzil M. Arefin, Yuki Mori, Maiken Nedergaard, Lauren M. Hablitz. Chronotherapy to reinforce circadian rhythms improves poststroke outcomes and glymphatic function in mice. Journal of Clinical Investigation, 2026; 136 (12) DOI: 10.1172/JCI201800

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Natural Peptide Counters Multiple Hallmarks of Alzheimer’s

 

Can your doctor rub a couple of neurons together and get human testing going? Or is sitting with heads up the ass the likely outcome?

Natural Peptide Counters Multiple Hallmarks of Alzheimer’s

Summary:

Researchers at UC San Diego have identified  (CST), a naturally occurring peptide fragment, that simultaneously reduces amyloid and tau buildup, quells neuroinflammation, and improves cognitive and motor performance in mouse models of neurodegenerative disease. Unlike single-target therapies, CST acts across several interconnected pathological pathways, pointing toward a versatile peptide-based treatment strategy for complex dementias.

Key Facts:

• Multi-Target Clearance: In preclinical mouse models, treatment with catestatin significantly reduced toxic accumulations of both tau and amyloid proteins while dialing down neuroinflammation.
• Functional Recovery: Beyond clearing hallmark neuropathology, the peptide led to measurable improvements in both cognitive performance and motor coordination in animal models.
• Derived from Chromogranin A: CST is an endogenous cleavage product of chromogranin A, a protein fundamental to neurotransmitter storage and cellular signaling, and is currently being explored for its ability to reprogram brain energy metabolism to shield vulnerable neurons against cellular stress.

Source: University of California San Diego School of Medicine

Alzheimer’s disease and related dementias present one of the most stubborn hurdles in modern neurology, primarily because their pathology is not driven by a single isolated defect. Instead, disease progression involves an entangled network of problems: aberrant protein aggregation, persistent neuroinflammation, metabolic dysfunction, and progressive synaptic failure.

While many experimental drugs focus narrowly on single targets, such as clearing amyloid plaques or blocking tau tangles, a research team at the University of California San Diego School of Medicine and the VA San Diego Healthcare System took a different approach. In a study published in Molecular Therapy, the scientists investigated whether an endogenous peptide could intervene across multiple disease mechanisms simultaneously.

Their focus fell on catestatin (CST), a naturally occurring peptide fragment derived from chromogranin A. In animal models, CST not only cleared pathological hallmarks but also protected functional neural circuits.

“Neurodegenerative diseases involve multiple interconnected problems — including misfolded proteins, neuroinflammation and progressive dysfunction of brain cells,” said senior author Sushil K. Mahata, PhD, professor of medicine at UC San Diego School of Medicine and research physiologist at the VA San Diego Healthcare System.

“Our findings show that CST can act across several of these disease-associated pathways and shift the brain toward a healthier state. More broadly, the study suggests that peptide-based therapies may offer a new approach to treating complex neurodegenerative diseases.”

Reducing Amyloid, Tau, and Neuroinflammation

To evaluate the peptide’s therapeutic potential, the investigators administered CST to mouse models displaying hallmark features of neurodegenerative decline. The treatment produced widespread structural and cellular benefits:

• Toxin Clearance: CST significantly blunted the accumulation of both amyloid and tau aggregates, the twin proteinopathies characteristic of Alzheimer’s disease.
• Anti-Inflammatory Modulation: The peptide suppressed chronic neuroinflammatory signaling, reducing destructive immune activation in brain tissue.
• Behavioral and Motor Gains: Mice receiving CST demonstrated meaningful improvements in memory, learning tasks, and motor performance compared to untreated controls.

Because chromogranin A is naturally involved in cellular communication and the packaging and release of hormones and neurotransmitters, its derivative CST already plays diverse roles across cardiovascular, metabolic, and immune regulation throughout the body. This native systemic versatility appears to translate to the central nervous system, where it orchestrates several defensive processes rather than engaging only one receptor.

Cellular Resilience and Metabolic Support

Beyond cleaning up cellular debris and cooling inflammatory fires, the researchers are examining how CST alters neuronal bioenergetics.

“One exciting aspect of our findings is that CST may do more than reduce the pathological features of neurodegeneration. We are also investigating whether CST can alter how the brain produces and uses energy, which may help neurons become more resilient to the cellular stress that occurs during neurodegeneration,” said lead author Suborno Jati, PhD, a postdoctoral scholar at UC San Diego School of Medicine.

By potentially stabilizing how distressed brain cells generate and utilize ATP, CST could give damaged neurons the energetic bandwidth required to maintain synaptic communication despite accumulating toxic stressors.

The Path Forward

The researchers emphasize that the current findings are strictly preclinical. Moving CST or related peptide analogues from laboratory animal models into human clinical trials will require comprehensive studies to determine long-term safety, optimal dosing regimens, blood-brain barrier delivery dynamics, and clinical efficacy.

Nevertheless, the discovery highlights the promise of peptide therapeutics as multi-system regulators capable of treating the multifaceted biology of neurodegenerative decline.

Funding: The research was supported in part by grants from the National Institutes of Health and the U.S. Department of Veterans Affairs.

Mahata is founder of CgA Therapeuticals, Inc. and co-founder of Siraj Therapeutics. Mahata and Jati are listed as co-inventors on intellectual property related to the findings.

Editorial Notes:

• This article was edited by a Neuroscience News editor.
• Journal paper reviewed in full.
• Additional context added by our staff.

About this Genetics and Neuroregeneration Research:

• Media Contact: Miles Martin
• Source: UCSD
• Image Credit: Image credited to Neuroscience News
• Original Research is Open Access: Molecular Therapy (September 21, 2026). “Catestatin peptide ameliorates tauopathy and amyloidogenesis via adrenergic inhibition.” Authors: Suborno Jati, Satadeepa Kal, Daniel Munoz-Mayorga, Kechun Tang, Debashis Sahoo, Xu Chen, and Sushil K. Mahata.
• DOI: 10.1016/j.ymthe.2026.09.022

Rhythmic Bone Stimulation Revitalizes Brain Function After Stroke and Injury, According to Nature Neuroscience Study

 Have your competent? doctor and hospital guarantee that human testing will occur.

Assuredly your competent? doctor created protocols from similar research on vibration!

You didn't write a rehab protocol from all this earlier research, did you?

• focal muscle vibration (7 posts to May2020)

• vibration (37 posts to February 2011)

• Whole Body Vibration Therapy (7 posts to January 2016)

Rhythmic Bone Stimulation Revitalizes Brain Function After Stroke and Injury, According to Nature Neuroscience Study

Brain Recovery Techniques Following Stroke and Head Trauma

According to НВ — Техно: Researchers have discovered that gentle, rhythmic tapping or pressure applied to the shinbone significantly aids brain recovery after stroke and traumatic brain injury. This innovative approach, called DCTAL, was tested on mice and pigs, resulting in reduced brain cell death, lowered inflammation, and enhanced generation of new neurons. Published in the journal Nature Neuroscience, the findings revealed a remarkable increase in survival rates-from 20% to 90%-within two weeks after severe injuries.

How the DCTAL Technique Works

DCTAL involves softly compressing the tibia at a rate of two squeezes per second over a span of five days. Animals treated with this method lived on average five days longer. Additionally, mice exhibited more than a 50% reduction in movement impairments following the compression regimen. Memory performance in maze tests improved nearly fivefold just one week post-injury.

The study further demonstrated a 4.5-fold increase in immature neurons and almost a sixfold rise in neural stem cell populations within the brain. These findings suggest that mechanical stimulation of bones can trigger brain repair processes. Osteocytes, bone cells containing the PIEZO1 protein, play a crucial role-this protein responds to mechanical forces by releasing protective signaling molecules into the bloodstream that promote brain healing.

Given that stroke and traumatic brain injury are leading causes of disability and death worldwide, this breakthrough offers promising potential for developing new therapeutic strategies. Integrating DCTAL into medical practice could dramatically improve recovery outcomes for patients, while also alleviating burdens on healthcare systems globally.

This research opens exciting new avenues in neuroscience and rehabilitation medicine, laying the groundwork for future advances in treating brain injuries.

In addition to innovative techniques like DCTAL, recent studies have explored other methods for enhancing recovery, such as vagus nerve stimulation. This approach has shown promise in improving skill retention, indicating a growing interest in non-invasive therapies that stimulate neural pathways and promote healing after brain injuries.

Brain’s “Blue Place” Rewrites How Norepinephrine Drives Learning

 How will your competent? doctor use this to drive your relearning of movements, speech and sensation?  Your doctor is familiar with norepinephrine, right? 

NO? PURE INCOMPETENCE THEN!

• norepinephrine (6 posts to March 2013)

Do you prefer your doctor, hospital and board of director's incompetence NOT KNOWING? OR NOT DOING? Your choice; let them be incompetent or demand action!

Brain’s “Blue Place” Rewrites How Norepinephrine Drives Learning

Summary:

Challenging decades of assumptions that the brainstem’s locus coeruleus acts like an indiscriminate broadcast speaker, researchers at the Allen Institute have revealed that it operates as a highly targeted postal network routing distinct norepinephrine signals to precise anatomical destinations.

The study also reconstructed individual locus coeruleus neurons, uncovering one with an axon measuring over 70 centimeters, the longest single neuron ever documented in a mouse.

Key Facts:

• Targeted Delivery, Not a Foghorn: Neurons in the upper (dorsal) locus coeruleus project specifically upward to the cerebral cortex to convey learning signals, whereas lower (ventral) neurons project down to the brainstem and spinal cord to modulate basic environmental engagement.
• Record-Breaking Axon Length: The team found locus coeruleus axons average approximately 35 centimeters in length, with one reconstructed neuron measuring 70.32 cm,the longest brain cell ever recorded in a mouse.
• Therapeutic Implications: Because locus coeruleus cells degenerate early in Alzheimer’s disease and norepinephrine pathways are primary targets for ADHD, depression, and anxiety drugs, this circuit map provides a blueprint for therapies that target specific pathways rather than flooding the entire brain.

Source: Allen Institute

Beyond the Loudspeaker Model

Deep within the brainstem lies a small, pigmented cluster of cells known as the locus coeruleus (LC), Latin for the “blue place.” Despite comprising only a tiny fraction of the brain’s total cell count, the LC wields outsized influence by serving as the primary source of norepinephrine (NE), a master neurotransmitter governing attention, stress, arousal, heart rate, and learning.

For decades, neuroscientists hypothesized that the locus coeruleus acted like a uniform broadcast horn, releasing a generalized surge of norepinephrine across the entire brain whenever an organism encountered stress or novelty.

Now, a comprehensive study published in Nature led by scientists at the Allen Institute refutes that model. Combining large-scale brain imaging, electrophysiological recordings, single-cell genetics, and behavioral tasks in mice, researchers proved that the LC routes tailored messages with remarkable anatomical and functional specificity.

“The findings suggest the brain’s norepinephrine system is far more like a targeted postal network than a foghorn,” said Karel Svoboda, Ph.D., director of Neural Dynamics at the Allen Institute and study co-author.

Segregated Circuits for Learning and Engagement

By tracing the anatomical wiring and genetic profiles of LC cells, the research team discovered a strict spatial divide:

• Dorsal LC Neurons: Located in the upper portion of the cluster, these cells extend projections upward into the forebrain and cerebral cortex. During behavioral tasks, they fire when mice update decisions after receiving negative feedback, actively driving learning and behavioral adaptation.
• Ventral LC Neurons: Positioned in the lower tier, these cells project downward to the brainstem and spinal cord. Their firing spikes immediately before animals choose to disengage or ignore cues offering potential rewards.

“What emerged was a clear map: neurons in the dorsal LC that send signals upward to the cortex are involved in learning, whereas neurons in the ventral region projecting downward to the brainstem and spinal cord govern whether animals engage with their environment at all,” Svoboda explained. “We also showed that these anatomical differences are mirrored by distinct gene expression patterns.”

The Longest Axon in the Mouse Brain

The sheer scale of the cells within this compact hub astonished researchers. Whole-brain imaging across nearly 35,000 neurons, combined with the genetic profiling of roughly 400,000 cells, enabled complete morphological reconstructions of individual LC projections.

The team determined that locus coeruleus axons average 35 centimeters in length. One standout neuron possessed an axon measuring 70.32 centimeters (over 27 inches), the longest individual neuron ever documented in a mouse.

“This neuron, like many others that we studied, supplies NE to a very large volume of the cerebral cortex. For the brain, this is highly unusual. Most neurons are more specific in their targets,” said study co-author Jeremiah Cohen, Ph.D., a scientist at the Allen Institute. “But this neuron doesn’t release NE everywhere. It ignores the cerebellum, brainstem, and spinal cord.”

A Dual-Engine Learning Platform

The authors noted parallels between the locus coeruleus and the brain’s dopamine system. While dopamine transmits reinforcement signals to the basal ganglia to guide habit formation, dorsal norepinephrine projections simultaneously deliver error and learning signals to the cortex. Working together, these systems form a coordinated computational platform that allows animals to learn complex and abstract rules concurrently.

These architectural insights offer immediate relevance for medicine. The locus coeruleus is among the earliest brain structures to degenerate in Alzheimer’s disease, and its signaling is modulated by common medications prescribed for ADHD, clinical depression, and anxiety disorders. Rather than broadly elevating or suppressing norepinephrine throughout the central nervous system, future psychiatric and neuroprotective interventions could be designed to modulate specific subcircuits while sparing others.

Funding: Supported by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies® (BRAIN) Initiative.

Editorial Notes:

• This article was edited by a Neuroscience News editor.
• Journal paper reviewed in full.
• Additional context added by our staff.

About this Neuroscience and Learning Research:

• Media Contact: Peter Kim
• Source: Allen Institute
• Image Credit: Image credited to Allen Institute
• Original Research is Open Access: Nature (September 16, 2026). “Topographic structure and function of locus coeruleus noradrenaline neurons” Authors: Zhixiao Su, Polina Kosillo, Kanghoon Jung, Shuonan Chen, Mathew T. Summers, Alex Piet, Han Hou, Kenta M. Hagihara, Drew Friedmann, Olivia Ho-Shing, Matthew I. Becker, Thomas Chartrand, Xinxin Yin, Peter Grotz, Ella Hilton-VanOsdall, Margaret Lee, Rajvi Javeri, Samantha L. Tuggle, Naveen Ouellette, Holly Myers, Judith Baka, Camilo Laiton, Kaelin Wulf, John Rohde, Alessio P. Buccino, Cameron Arshadi, Di Wang, Sharmishtaa Seshamani, Sonya Vasquez, Carolyn M. Eng, Douglas R. Ollerenshaw, Nick Dee, Tamara Casper, Windy Ho, Matthew Jungert, Atlas Jordan, Elliot Phillips, Anish Bhaswanth Chakka, Kamiliam Nasirova, Krista Blake, Audrey McCutcheon, Megan Koch, Maria Camila Vergara, Kimberly A. Smith, Tim Jarsky, Nicholas Lusk, Mara C. P. Rue, Xiaoyin Chen, Joshua H. Siegle, Adam K. Glaser, Brian R. Lee, Karel Svoboda, Yoh Isogai, Jayaram V. Chandrashekar & Jeremiah Y. Cohen.
• DOI: 10.1038/s41586-026-11026-0

Astrocytic Gq pathway activation enhances the efficacy of rehabilitation after stroke

 You'll have to get your incompetent? doctor and hospital to get human testing going! But that won't occur, will it?

Astrocytic Gq pathway activation enhances the efficacy of rehabilitation after stroke

, , , , ,

a

Department of Molecular Neuroscience, Graduate School of Medicine, The University of Osaka, Osaka, 565-0871, Japan

b

Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Osaka, Osaka, 565-0871, Japan

c

Department of Neuro-Medical Science, Graduate School of Medicine, The University of Osaka, Osaka, 565-0871, Japan

d

WPI Immunology Frontier Research Center, The University of Osaka, Osaka, 565-0871, Japan

e

Graduate School of Frontier Bioscience, The University of Osaka, Osaka, 565-0871, Japan

Highlights

• •
  Peri-infarct astrocytes are selectively activated using chemogenetics.
• •
  Astrocytic activation alone is insufficient for functional recovery.
• •
  Astrocytic activation potentiates rehabilitation-induced motor recovery.

Abstract

Stroke is a leading cause of functional impairment. As rehabilitation has a limited effect, it is essential to advance future treatments and enhance the efficacy of rehabilitation. This study focused on the use of astrocytes to augment the efficacy of rehabilitation for strokes. It utilized chemogenetics to specifically activate astrocytes in the peri-infarct region of a mouse photothrombosis model. The mice were subjected to immunohistochemical analysis and behavioral tests to evaluate the effects of astrocytic Gq pathway activation after an induced stroke. The timing of astrocytic activation was separated from that of rehabilitative training. It was observed that chemogenetic astrocytic activation prior to rehabilitation significantly augmented the efficacy of the training and promoted functional motor recovery after the induced stroke. Consequently, a better understanding of this mechanism could be a significant step toward future therapeutic breakthroughs.

An injectable biomaterial scaffold aids tissue repair following stroke in mice

 Of course your incompetent? doctor and hospital won't get human testing going.

Other scaffolds your doctor already has been working on.

• scaffolds (30 posts to December 2011)

An injectable biomaterial scaffold aids tissue repair following stroke in mice

Original story from Duke University (NC, USA).

Delivered more than 24 hours after a stroke in mice, an injectable biomaterial harnesses the immune system to promote vascular repair, neural remodeling and improved motor performance.

Biomedical engineers at Duke University (NC, USA) have developed an injectable biomaterial that helps transform the cavity left behind after a stroke caused by a blood clot into an environment more supportive of repair. By recruiting the body’s own immune cells, the treatment promoted the growth of new blood vessels, supported neural remodeling and improved motor performance in mice.

Every year, millions of people experience strokes caused by blood clots, called ischemic strokes. Immediate treatments, including clot-dissolving drugs and mechanical removal of the clot, can restore blood flow and preserve threatened brain tissue. But these treatments cannot replace tissue that has already been lost.

Large strokes can result in substantial tissue loss and leave behind a cavity at the site of the injury. After the clot is removed, recovery relies largely on rehabilitation, which helps surviving brain circuits adapt but does not directly repair the damaged area.

“Once brain tissue has been lost, restoring blood flow is no longer enough,” commented Tatiana Segura, the Robert Plonsey Distinguished Professor of Biomedical Engineering at Duke. “Our goal is to engineer the injured space so that immune, vascular and neural repair processes can begin to work together.”

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Bioprinting technique supports bone tissue regeneration

An interdisciplinary team of engineers and chemists has laid the groundwork to 3D print spheroids — tiny clusters of living cells — capable of regenerating bone tissue in response to severe trauma or infections.

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Segura and her team set out to create those conditions by using MAPS, or microporous annealed particle scaffolds, which are individual hydrogel microparticles that form a porous microstructure for cells to build on to regrow neural tissue. Building on their earlier successes with the innovative biomaterial, they looked to harness the abilities of the body’s immune system to guide and improve repairs.

To pull in helpful immune cells, the team turned to astrocytes, star-shaped cells that support normal brain function and respond rapidly to injury. Astrocytes communicate with other cells in part by releasing extracellular vesicles (EVs), which are nanoscale packages that carry proteins, lipids and genetic material.

The researchers collected EVs from lab-grown astrocytes and experimented with adding various signaling molecules to attract immune cells and promote vascular repair and functional improvement. Rather than simply injecting the EVs, the team used a chemical reaction to anchor them to the surfaces of the hydrogel microparticles. This kept the signals localized within the scaffold, where incoming cells could encounter them.

“We are not simply placing a material into the brain,” Segura explained. “We are engineering a local environment that can coordinate several parts of the repair response.”

One combination of signaling molecules, IL-4 and C1q, proved best at attracting helpful immune cells into the damaged region, including macrophages and an unexpectedly persistent population of neutrophils. Neutrophils are commonly associated with inflammation and tissue damage during the early stages of stroke. But the study suggests that, at a later stage and within the right material environment, these cells can also contribute to repair.

When the researchers depleted the neutrophil-rich immune-cell population, blood vessel growth and scaffold remodeling were markedly reduced. This finding showed that the cells were important contributors to the repair response.

“This result changes how we think about neutrophils after stroke,” shared Shangjing Xin, lead scientists of the study and a postdoctoral fellow in the Segura laboratory. “Their role appears to depend on when they arrive, where they are located and the signals they receive from their surroundings. Our study demonstrates a potential engineering strategy to recruit and retain these cells at the right time.”

The immune response was accompanied by the formation of blood vessels throughout the treated cavity. The researchers also observed increased axonal fibers, which are key structures in brain cells, within and around the damaged region.

Mice receiving the optimized scaffold also performed better on a grid-walking test that measures errors in forelimb placement. By eight weeks, their performance was statistically indistinguishable from that of healthy control mice, and the improvement was sustained throughout the study.

Importantly, EVs delivered without the MAP scaffold did not produce comparable vascular repair. This result showed that the biomaterial was not simply carrying a therapeutic cargo. Its porous structure and ability to localize the EV signals were essential to the response.

While these findings are a step in the right direction, the findings remain preclinical. The evolving treatment was tested in mouse models by directly injecting it into the damaged site. Additional studies will be required to evaluate its safety, determine how the different immune-cell populations contribute to recovery, and test the approach in larger and more clinically representative stroke models.

The current study used EVs collected from primary rat astrocytes. As a next step, the Segura laboratory is exploring EVs produced by human induced pluripotent stem cell-derived astrocytes. This approach could provide a more scalable and clinically relevant source of EVs while allowing the researchers to better control the signals they carry.

“You do not restore an ecosystem simply by containing the initial damage,” Segura concluded. “You have to create the conditions that allow life to return. That is how we think about the stroke cavity. The material is not intended to reproduce the brain itself, but to create an environment where the body’s own cells can enter, communicate and participate in rebuilding vascularized tissue.”

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This article has been republished from the following materials. Material may have been edited for length and house style. For further information, please contact the cited source. Our press release publishing policy can be accessed here.

Source

1. Xin S, Zhang L, Phan NV et al. IL-4/C1q activated astrocyte-derived extracellular vesicles promote stroke infarct recovery by recruiting peripheral leukocytes. Cell Biomater. doi: 10.1016/j.celbio.2026.100543 (2026) (Epub ahead of print).