Bacteria invade brain after implanting medical devices

New research could transform design of brain implants for neurological disorders to make them safer, more effective

Case Western Reserve University

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Jeff Capadona

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Credit: Case Western Reserve University

CLEVELAND—Brain implants hold immense promise for restoring function in patients with paralysis, epilepsy and other neurological disorders.

But a team of researchers at Case Western Reserve University has discovered that bacteria can invade the brain after a medical device is implanted, contributing to inflammation and reducing the device’s long-term effectiveness. 

The groundbreaking research, recently published in Nature Communications, could improve the long-term success of brain implants now that a target has been identified to address.

“Understanding the role of bacteria in implant performance and brain health could revolutionize how these devices are designed and maintained,” said Jeff Capadona, Case Western Reserve’s vice provost for innovation, the Donnell Institute Professor of Biomedical Engineering and senior research career scientist at the Louis Stokes Cleveland VA Medical Center.

Capadona’s lab led the study, which examined the presence of bacterial DNA in the brains of mouse models implanted with microelectrodes.

To their surprise, researchers found bacteria linked to the gut inside the brain. The discovery suggests that a breach in what is known as “the blood-brain barrier,” caused by implanting the device, could allow microbes to enter.

“This is a paradigm-shifting finding,” said George Hoeferlin, the study’s lead author, who was a biomedical engineering graduate student at Case Western Reserve in Capadona’s lab. “For decades, the field has focused on the body's immune response to these implants, but our research now shows that bacteria—some originating from the gut—are also playing a role in the inflammation surrounding these devices.”

In the study, mouse models treated with antibiotics had reduced bacterial contamination and the performance of the implanted devices improved—although prolonged antibiotic use proved detrimental.

The discovery’s implications go beyond device failure. Some of the bacteria found in the brain have been linked to neurological diseases, including Alzheimer's, Parkinson’s and stroke.

“If we’re not identifying or addressing this consequence of implantation, we could be causing more harm than we’re fixing,” Capadona said. “This finding highlights the urgent need to develop a permanent strategy for preventing bacterial invasion from implanted devices, rather than just managing inflammation after the fact. The more we understand about this process, the better we can design implants that work safely and effectively.”

Capadona said his lab is now expanding the research to examine bacteria in other types of brain implants, such as ventricular shunts used to treat hydrocephalus, an abnormal buildup of fluid in the brain.

The team also examined the fecal matter of a human subject implanted with a brain device and found similar results.

“This finding stresses the importance of understanding how bacterial invasion may not just be a laboratory phenomenon, but a clinically relevant issue,” said Bolu Ajiboye, the Robert and Brenda Aiken Professor in biomedical engineering at the Case School of Engineering and School of Medicine and scientist at the Cleveland VA Medical Center. “Through our strong translational pipeline between CWRU and the VA, we are now investigating how this discovery can directly contribute to safer, more effective neural implant strategies for patients.”

The research was supported by the U.S. Department of Veterans Affairs’ Advanced Platform Technology Center, National Institutes of Health, Department of Defense and the Donnell Institute Professorship Endowment.

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At Case Western Reserve, one of the nation's leading research universities, we're driven to seek knowledge and find solutions to some of the world's most pressing problems. Nearly 6,200 undergraduate and 6,100 graduate students from across 96 countries study in our more than 250 degree programs across arts, dental medicine, engineering, law, management, medicine, nursing, science and social work. Our location in Cleveland, Ohio—a hub of cultural, business and healthcare activity—gives students unparalleled access to engaging academic, research, clinical, entrepreneurial and volunteer opportunities and prepares them to join our network of 125,000+ alumni making an impact worldwide. Visit case.edu to learn more.

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Journal

Nature Communications

Article Title

Bacteria invade the brain following intracortical microelectrode implantation, inducing gut-brain axis disruption and contributing to reduced microelectrode performance

 

Diverging views of democracy fuel support for authoritarian politicians, Notre Dame study shows

By Renée LaReau

University of Notre Dame

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Marc Jacob, assistant professor of democracy and global affairs in the Keough School of Global Affairs at the University of Notre Dame.

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Credit: University of Notre Dame

Why do people living in democratic countries vote for political candidates who openly violate democratic standards? A new study by a University of Notre Dame researcher found that diverse understandings of democracy among voters can lead to votes for authoritarian-leaning political leaders.

“A considerable variety in democratic views leads part of the electorate to overlook violations of democratic norms such as minority rights protection or restraints on executive power,” said Marc Jacob, assistant professor of democracy and global affairs at Notre Dame’s Keough School of Global Affairs. “These varied attitudes represent an important vulnerability for the democratic system as they can enable authoritarian political candidates to access and retain power.”

The study, which was published in the British Journal of Political Science, found that voters' differing conceptions of democracy shape their ability to recognize democratic violations and, in turn, affect their voting choices.

Jacob and co-authors Natasha Wunsch of the University of Fribourg, Switzerland, and Laurenz Derksen of ETH Zurich conducted a candidate choice experiment in Poland, a democracy where elections remain competitive despite some democratic backsliding over the past several years. (Democratic backsliding occurs when existing democracies slip backward toward autocracy and is currently taking place in every region of the world.)

The researchers found that respondents who supported democracy in principle but adhered less strongly to liberal democratic norms, such as minority rights protection and constraints on executive power, tolerated democratic violations more readily.

“Where liberal democratic commitment is weak or unevenly distributed across the electorate, voters cannot reliably act as safeguards against democratic backsliding,” Jacob said.

Conversely, voters who subscribed more strongly to a liberal understanding were more likely to vote against non-liberal candidates, even those from their own political party.

Jacob said that additional survey-based research and qualitative approaches such as focus groups may provide further insights into citizens’ divergent understandings of democracy. To counter further democratic backsliding, the researchers recommend extensive and deliberate investment in civic education of citizens that highlights how each individual benefits from democratic governance, especially in more recent democracies.

“Democracy education often features big, abstract ideas, but it’s just as important to show people how civil liberties, power-sharing and the rule of law directly benefit them — and to remind them that their votes play a crucial role in keeping those values alive.”

The study was funded by the Swiss National Science Foundation.

Contact: Tracy DeStazio, associate director of media relations, 574-631-9958 or tdestazi@nd.edu

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Journal

British Journal of Political Science

DOI

10.1017/S0007123424000711 

Method of Research

Experimental study

Subject of Research

People

Article Title

The Demand Side of Democratic Backsliding: How Divergent Understandings of Democracy Shape Political Choice

Article Publication Date

17-Mar-2025

Food and non-alcoholic drink products in Mexico were substantially reformulated to be healthier following the 2020 introduction of warning labels identifying products with excessive content of calories, fat, salt, sugar, sweetener and caffeine

PLOS
News Release 18-Mar-2025




Mexican warning labels on canned soft drinks.

In your coverage, please use this URL to provide access to the freely available paper in PLOS Medicine:

http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1004533

Article title: Product reformulation in non-alcoholic beverages and foods after the implementation of front-of-pack warning labels in Mexico

Author countries: Mexico

Funding: see manuscript

Journal

PLOS Medicine

DOI

10.1371/journal.pmed.1004533

Method of Research

Observational study

Subject of Research

People

 

Conservation efforts analysis reveals which actions are most helpful for endangered species status

Data show success in conserving species at greatest risk of extinction, but limited biodiversity recovery

PLOS

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Species that have improved status following conservation efforts. From top-left to bottom-right: Mauritian kestrel (Falco punctatus, Josh Noseworthy, CC BY 2.0), Pemba flying fox (Pteropus voeltzkowi, Nigel Voaden, CC BY 4.0), Little spotted kiwi (Apteryx owenii, Kimberley_collins, CC BY 2.0), Sierra Juarez Brook frog (Duellmanohyla ignicolor, Medardo_Arreortua, CC BY 4.0), Cook’s petrel (Pteroroma cookie, sussexbirder, CC BY 2.0), European bison (Bison bonasus, Oleg Kosterin, CC BY 4.0), Utahm’s bush frog (Raorchestes uthamani, Ansil B.R., CC BY 4.0), Iberian lynx (Lynx pardinus, http://www.lynxexsitu.es, CC BY 3.0), Humpback whale (Megaptera novaeangliae, Christopher.Michel, CC BY 2.0).

 

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Credit: Compiled by Ashley Simkins (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)

Targeted conservation actions are essential to prevent wildlife extinctions, but more efforts are needed to fully recover biodiversity, according to a study published March 18th in the open-access journal PLOS Biology by Ashley Simkins of the University of Cambridge, UK and colleagues.

Out of over 166,000 species assessed by the International Union for Conservation of Nature, around 28% are threatened with extinction. Global efforts to prevent extinction and recover biodiversity have had some success, but there is limited data to show which conservation actions are most effective. In this study, Simkins and colleagues compile information on species conservation status and conservation actions to assess the latter’s impacts on species.

The researchers reviewed data for over 67,000 species on the IUCN Red List, including which conservation actions have been taken and how each species' conservation status has changed over time. They found that nearly every species with improving status has some form of conservation action in place, with improvement most often seen in species with reintroduction plans or species-targeted management plans. Approximately only half of assessed species have conservation actions in place, and roughly six times as many species have deteriorated in recent decades than have improved. Of the species that have seen improvements, very few have experienced full recovery from near-extinction to Least Concern status.

These results provide a broad picture of which conservation actions are especially helpful and which species still require conservation action. The analyses confirm that efforts to prevent extinction for species at greatest risk have often led to improvements, but actions have rarely lead to full recovery of species. The authors note that there remain gaps and uncertainties in the IUCN Red List data due to inconsistencies in assessment and documentation strategies across species. Improving documentation of conservation actions underway and scaling up conservation efforts will be essential to assist the recovery of biodiversity.

The authors add, “Despite huge losses and declines of species, we find conservation action has driven improvements in more than one hundred species, with almost all species improving in status having conservation actions in place. This suggests with greater resource allocation, conservation can halt and reverse biodiversity loss.”

 

In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/3FDvitU  

Citation: Simkins AT, Sutherland WJ, Dicks LV, Hilton-Taylor C, Grace MK, Butchart SHM, et al. (2025) Past conservation efforts reveal which actions lead to positive outcomes for species. PLoS Biol 23(3): e3003051. https://doi.org/10.1371/journal.pbio.3003051

Author countries: United Kingdom

Funding: ATS is supported through the Natural Environment Research Council’s C-CLEAR Doctoral Training Partnership (grant NE/S007164/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Journal

PLOS Biology

DOI

10.1371/journal.pbio.3003051 

Method of Research

Observational study

Subject of Research

Not applicable

COI Statement

Competing interests: LVD is a Board Member of Natural England. All other authors have declared that no competing interests exist.

Conservation efforts are bringing species back from the brink, even as overall biodiversity falls

University of Cambridge

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Conservation efforts are bringing species back from the brink, even as overall biodiversity falls. The Iberian lynx, once the world’s most endangered cat, has rebounded from just a few hundred individuals to a few thousand.

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Credit: Tris Allinson

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

The study draws on data from the IUCN Red List, the world’s largest database of species conservation status. The researchers say their results, reported in the journal PLOS Biology, highlight both the successes and the need for urgent action.

The world is facing a global biodiversity crisis, with 28% of more than 160,000 assessed species threatened with extinction, and an estimated one million species facing this fate due to human activities. However, conservation measures can be successful, if there is concrete evidence about what works.  

The researchers, led by the University of Cambridge with the IUCN, BirdLife International, and Oxford and Durham Universities, used Red List data to assess whether conservation measures had been put in place, and whether those actions had a positive impact on a given species’ conservation status.

“We found that almost all the species that have moved from a more threatened category to a less threatened category have benefitted from some sort of conservation measures,” said lead author Ashley Simkins, a PhD candidate in Cambridge’s Department of Zoology. “It’s a strong signal that conservation works.”

While there is no ‘one size fits all’ solution, the researchers observed some connections between conservation success stories. Many of these species live in isolated areas, such as islands, where intensive conservation efforts – such as habitat protection, captive breeding and reintroductions – can be fully implemented.

“While biodiversity loss is a genuine crisis, it’s vital that we celebrate the success stories wherever and whenever we can,” said Simkins. “It’s so hard for a species to improve its conservation status, but with the right effort, we can turn things around.”

The Iberian lynx, once the world’s most endangered cat, has rebounded from just a few hundred individuals to a few thousand. Likewise, the kākāpō, a flightless parrot from New Zealand, has benefitted from dedicated recovery programmes. And the European bison, which was hunted to extinction in the wild in the early 20th century, now roams parts of Eastern Europe thanks to sustained conservation efforts over decades.

Marine species have also seen dramatic recoveries. Humpback and blue whales, once driven to the brink of extinction by commercial whaling, have made a comeback after an international moratorium on whaling. However, despite these success stories, the study found that six times more species are declining than improving.

The researchers say that like human healthcare, preventative measures in conservation are preferable and more cost-effective to emergency interventions.

“Humans have gotten pretty good at what could be considered ‘A&E’ conservation – focusing on species at very high risk of extinction,” said Simkins. “What we’re less good at is preventing species from becoming threatened in the first place. We need to move beyond treating the symptoms of biodiversity loss and start addressing the root causes.”

The researchers also emphasise the need for collaborative, locally driven conservation. In Papua New Guinea, for example, conservationists worked with local communities to replace tree kangaroo hunting with sustainable forms of animal protein including farming of chickens and fishing —an approach that benefitted both people and wildlife.

“It’s vital that we as conservationists are working with stakeholders, rather than dictating to them, whether that’s an Indigenous community in Papua New Guinea or a farmer in Somerset,” said Simkins. “Conservation doesn’t have to be a zero-sum game – there are compromises that can benefit both the natural world and human society.”

“In this climate of constant stories about wildlife declines and insufficient political action to protect nature it’s important to realise that there are also many success stories and that conservation efforts are making a real, demonstrable impact in the world,” said co-senior author Dr Silviu Petrovan, also from the Department of Zoology. “Conservation works if given the chance.”

“This research sheds light on which actions to save species have been effective, and what interventions are needed,” said co-author Dr Stuart Butchart, Chief Scientist at BirdLife International. “Governments need to turn their words into actions, and rapidly scale up efforts to save species from extinction and help populations to recover. Safeguarding our natural heritage for future generations depends upon this.”

“The IUCN Red List of Threatened Species informs and guides on-the ground conservation decisions; actions which are further guided by the research presented in this publication,” said co-author Craig Hilton-Taylor, Head of the IUCN Red List.

“Almost everyone will have their own favourite example of a conservation success story, whether it’s the bald eagle in North America, or the red kite in the UK,” said Simkins. We need joint action to ensure these positive stories aren’t the exception – they’re the norm.”

The research was supported in part by the Natural Environment Research Council (NERC), part of UK Research and Innovation (UKRI).

The European bison, which was hunted to extinction in the wild in the early 20th century, now roams parts of Eastern Europe thanks to sustained conservation efforts over decades.

Credit

Rafal Kowalczyk

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

Credit

Paul Donald

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

Credit

Mihai Leu

Journal

PLOS Biology

DOI

10.1371/journal.pbio.3003051 

Article Title

Past conservation efforts reveal which actions lead to positive outcomes for species

Article Publication Date

18-Mar-2025