The study, led by Luiz Bertassoni, D.D.S., Ph.D., founding director of the Knight Cancer Precision Biofabrication Hub and a professor at the OHSU Knight Cancer Institute and the OHSU School of Dentistry, shows that perivascular cells sense changes in nearby tissues and send signals that disrupt blood vessel function, worsening disease progression.

Nearly a decade ago, Bertassoni and his team developed a method to 3D print blood vessels in the lab — a breakthrough recognized as one of the top scientific discoveries of the year by Discover magazine. Since then, they’ve focused on engineering blood vessels that better mimic those in the human body to study more complex diseases.

“Historically, endothelial cells lining blood vessels have been considered the main contributors of vascular disease,” Bertassoni said. “Our findings represent a paradigm shift, showing how perivascular cells, instead, act as important sentinels. They detect changes in tissues and coordinating vascular responses. This opens the door to entirely new treatment strategies.”

Cristiane Miranda Franca, D.D.S., Ph.D., the study’s lead author, is an assistant professor in the OHSU School of Dentistry and holds appointments with the OHSU Knight Cancer Precision Biofabrication Hub and Knight Cancer Institute’s Cancer Early Detection Advanced Research Center, or CEDAR.

“The applications of this research are wide,” she said. “We’ve shown for the first time how perivascular cells trigger inflammation and signal blood vessel changes when surrounding tissues are altered.”

The study used an innovative “blood vessel on-a-chip” model developed by Christopher Chen, M.D., Ph.D., and his team from Boston University and the Wyss Institute at Harvard, who are collaborators on this project. By replicating conditions like tissue stiffening and scarring — common in aging, chronic diseases and cancer — the researchers discovered that perivascular cells drive blood vessel leakage and distortion, worsening inflammation and disease.

Learn more: OHSU Knight Cancer Institute offers the latest treatments, technologies, hundreds of research studies and clinical trials

“When we removed perivascular cells, blood vessels essentially failed to respond to tissue changes,” Franca said.

The findings shed light on the relationship between the extracellular matrix, blood vessel function and disease progression. Perivascular cells could become targets for therapies aimed at restoring normal vascular function and reducing the progression of various diseases such as fibrosis, diabetes and cancer.

Importantly, the research also holds promise for cancer prevention and early intervention. Early detection and treatment of changes in these cells could help stop tumors before they grow.

“If we intervene early, we might prevent precancerous lesions from advancing to full-blown cancer,” Bertassoni said. “This could revolutionize how we approach cancer prevention and treatment.”

In addition to Bertassoni and Franca, OHSU co-authors include Maria Elisa Lima Verde, Ph.D., Alice Correa Silva-Sousa, D.D.S., Ph.D., Amin Mansoorifar, Ph.D., Avathamsa Athirasala, M.S., Ramesh Subbiah, Ph.D., Anthony Tahayeri, B.S., Mauricio Sousa, D.D.S., M.S., Ph.D., May Anny Fraga, D.D.S., M.S., Rahul Visalakshan, Ph.D., Aaron Doe, M.S., Keith Beadle, B.S., and McKenna Finley, B.A. Co-authors also include Emilios Dimitriadis, Ph.D., with the National Institute of Biomedical Imaging and Bioengineering; Jennifer Bays, Ph.D., and Marina Uroz, Ph.D., with Boston University; and Kenneth Yamada, M.D., Ph.D., with the National Institute of Dental and Craniofacial Research of the National Institutes of Health.

People who have limited access to air conditioning may be at higher risk of seeking emergency care for health problems following exposure to wildfire smoke, according to a new study led by Boston University School of Public Health (BUSPH).

Posted online ahead of publication in the journal Environmental Research: Health, the study found that exposure to fine particle matter (PM2.5) from wildfire smoke in California is associated with higher rates of emergency department visits for all causes, non-accidental causes, and respiratory disease. This risk varied by age and race, but was especially high for individuals who lived in areas with lower availability of air conditioning.

The findings come at a critical time, as firefighters in Southern California continue to battle multiple wildfires that have been blazing in and around Los Angeles County since Tuesday, January 7 — including the Palisades fire, which is likely the largest and most destructive wildfire in the county’s history. Health experts are urging residents who are not under evacuation orders and can safely remain in their homes to turn on air conditioners and/or air purifiers if they have access to these devices.

Despite this guidance — and the growing threat of more frequent and intense wildfires due to worsening climate change — very little research has examined how the health effects of wildfire smoke exposure may differ based on individuals’ access to air conditioning. Understanding this relationship can inform policies and interventions that mitigate barriers to air conditioners and protect vulnerable populations from the consequences of inhaling PM2.5 and other harmful pollutants from this smoke, which can permeate the air from hundreds or thousands of miles away.

“Depending on the type of system and filter used, air conditioning may modify the impact of smoke exposure on human health,” says study lead and corresponding author Dr. Jennifer Stowell, research scientist in climate and health at BUSPH, noting that the analysis only addressed the likelihood of access to air conditioning, rather than air conditioning types or actual usage. “Studies like these will become more and more relevant as wildfire exposure increases. California is, perhaps, the best example of this in the US, with bigger fires and longer fire seasons. An important next step will be to identify ways to better characterize access to air conditioning.”

For the study, Dr. Stowell and colleagues from BUSPH, Boston University College of Arts & Sciences (CAS), and the Health Effects Institute utilized a nationwide dataset of healthcare claims to assess more than 50,000 emergency department visits during the 2012-2019 California wildfire seasons, which occurred from May to November each year. They quantified the adverse health effects from PM2.5 exposure among all study participants, as well as subgroups of participants.

Consistent with prior research, wildfire smoke exposure was most strongly associated with emergency department visits for respiratory issues, but not cardiovascular-related complications. These visits were generally higher among children under 10 years old, adults between 20-74 years old, and among the Black population, although also elevated among White, Hispanic, and Asian/Pacific Islander populations.

People living in areas with lower availability of air conditioning had a 22-percent greater risk of visiting the emergency department for respiratory conditions associated with wildfire smoke exposure. Greater insight into air conditioning use as a pollutant-filtering tool and the barriers that certain populations face in accessing these cooling systems is critical, as wildfires are expected to occur more regularly in the Wildland-Urban Interface (WUI) — areas where human activity is in close contact with sources of dry fuel. This is exactly what is happening now in LA County, Dr. Stowell says, as the fires destroy thousands of homes and businesses near vegetation.

“WUI fires are particularly concerning due to the burning of human-made structures and the additional toxic chemicals and particulates that can be found in their smoke plume,” says Dr. Stowell. “The current fires in LA are out-of-season fires driven by severe Santa Ana winds coming from the mountains. As climate change continues, the temperature differentials between land and sea will grow and, potentially, drive stronger and stronger late-season or out-of-season wind events.”

So how may residential air conditioners help dispel PM2.5 from homes? The filters in these cooling systems can remove particulate matter, although certain filters are more effective at filtering particulate matter than others. “HEPA filters can remove the majority of particles greater than 0.3 µm, but they are significantly more expensive than fiberglass air filters, which only remove larger particles and may allow high amounts of fine particulate matter to penetrate indoors,” Dr. Stowell says. “Generic pleated air filters are also fairly efficient at filtering out most particulate matter.”

Air conditioning systems with a Minimum Efficiency Reporting Value (MERV) rating of seven or higher are thought to be the most efficient at removing particulate matter from outdoor air, but are also more expensive.

The study findings indicate a need for stronger policy measures that can reduce the health risks associated with wildfire smoke exposure.

“Many homeowners do not understand the differences between MERV ratings and how these might impact your health,” Dr. Stowell says. “Policymakers should consider delivering better information to the public — such as the types and ratings of filters that perform better — especially for those who reside in smoke-prone regions.”

Given that marginalized populations appear to be disproportionately burdened by the health effects of wildfire smoke exposure, economic assistance should also be considered, she says, particularly for low-income populations residing in smoke-prone regions. “Considering the current fires in CA, local and state governments should heighten their responses to these events and develop plans and policies to reduce exposure before the fires occur,” Dr. Stowell says.

The study’s senior author is Dr. Gregory Wellenius, professor of environmental health and director of the Center for Climate and Health at BUSPH. The study was coauthored by Dr. Ian Sue Wing, professor of earth and environment at CAS; Dr. Yasmin Romitti, staff scientist at the Health Effects Institute, and Dr. Patrick Kinney, Beverly Brown Professor of Urban Health at BUSPH.

UC Riverside scientists have now discovered a chemical that plants produce when they’re stressed prevents biofilm from forming. The breakthrough offers potential advances in healthcare as well as preventing equipment corrosion in industrial settings.

“In simple terms, biofilms are communities of microorganisms, like bacteria or fungi, that stick together and form a protective layer on surfaces,” said Katayoon Dehesh, distinguished professor of molecular biochemistry at UCR, and corresponding author of a study about the discovery.

“You’ve probably seen them as the slimy layer on river rocks or the plaque on your teeth. While they’re a natural part of many ecosystems, biofilms can cause big problems.”

The study, published in the journal Nature Communications, highlights the importance of a particular metabolite, which is a molecule produced during life-sustaining chemical reactions inside plants, as well as bacteria and even some parasites, like the one that causes malaria.

In plants, this metabolite, MEcPP, plays a critical role not only in producing essential compounds but also in stress signaling. For example, when a plant is damaged in some way and too much oxygen enters its cells, it accumulates MEcPP. This molecule then triggers protective responses within the plant. The researchers discovered that this same molecule has a surprising effect on bacteria like E. coli: it disrupts biofilm development by interfering with its ability to attach to surfaces.

In medical settings, biofilms grow on devices like catheters, stents, or implants, making infections harder to treat because the microbes in biofilms are highly resistant to antibiotics. In industrial contexts, they clog pipes, contaminate food processing equipment, and cause corrosion.

“By preventing the early stages of biofilm development, this molecule offers real potential to improve outcomes in any industries reliant on clean surfaces,” Dehesh said.

Bacteria rely on hair-like structures called fimbriae to anchor themselves to surfaces, a critical step in biofilm initiation. Fimbriae help bacteria latch onto medical implants, pipes, or even teeth, where they secrete a protective matrix that shields them from antibiotics and cleaning agents. Without fimbriae, biofilm formation cannot begin.

“Biofilms are like fortresses for bacteria,” said Jingzhe Guo, UCR project scientist and first author of the paper. “By disrupting the initial phase of attachment, MEcPP essentially disarms the bacteria’s ability to establish these fortresses.”

Through genetic screenings of more than 9,000 bacterial mutants, the research team identified a key gene called fimE, which acts as an “off switch” for fimbriae production. MEcPP enhances the activity of this gene and increases the expression of fimE. This, in turn, prevents the bacteria from producing fimbriae and forming biofilms.

“Our discovery could inspire biofilm prevention strategies across a wide range of industries,” Guo said. “From cleaner water systems to better dental care products, the possibilities are immense.”

Biofilms are not only a medical concern but also a costly problem in industrial settings. They contribute to clogged pipelines, corroded machinery, and contamination in food processing facilities. Traditional methods for managing biofilms often rely on harsh chemicals or expensive treatments, which can be harmful to the environment or ineffective over time as bacteria adapt.

“This study is a testament to the unexpected connections between plant biology and microbiology,” Guo said. “It’s thrilling to think a molecule that plants use to signal stress might one day help humans combat bacterial threats.”

While previous research focused on how well organic solar cells converted light to electricity following radiation exposure, the new investigation also dug into what happens at the molecular level to cause drops in performance.

“Silicon semiconductors aren’t stable in space because of proton irradiation coming from the sun,” said Yongxi Li, first author of the study to be published in Joule and a U-M associate research scientist in electrical and computer engineering at the time of the research. “We tested organic photovoltaics with protons because they are considered the most damaging particles in space for electronic materials.”

Space missions often land on gallium arsenide for its high efficiency and resistance to damage from protons, but it’s expensive and, like silicon, is relatively heavy and inflexible. In contrast, organic solar cells can be flexible and are much lighter. This study is among those exploring the reliability of organics, as space missions tend to use highly trusted materials.

Organic solar cells made with small molecules didn’t seem to have any trouble with protons — they showed no damage after three years worth of radiation. In contrast, those made with polymers — more complex molecules with branching structures — lost half of their efficiency.

“We found that protons cleave some of the side chains, and that leaves an electron trap that degrades solar cell performance,” said Stephen Forrest, the Peter A. Franken Distinguished University Professor of Engineering at U-M, and lead corresponding author of the study.

These traps grab onto electrons freed by light hitting the cell, preventing them from flowing to the electrodes that harvest the electricity.

“You can heal this by thermal annealing, or heating the solar cell. But we might find ways to fill the traps with other atoms, eliminating this problem,” Forrest said.

It’s plausible that sun-facing solar cells could essentially self-heal at temperatures of 100°C (212°F) — this warmth is enough to repair the bonds in the lab. But questions remain: for instance, will that repair still take place in the vacuum of space? Is the healing reliable enough for long missions? It may be more straightforward to design the material so that the performance-killing electron traps never appear.

Li intends to explore both avenues further as an incoming associate professor of advanced materials and manufacturing at Nanjing University in China.

The research is funded by Universal Display Corp and the U.S. Office of Naval Research.

The devices were built in part at the Lurie Nanofabrication Facility, exposed to a proton beam at the Michigan Ion Beam Laboratory, and studied at the Michigan Center for Materials Characterization.

The team has applied for patent protection with the assistance of U-M Innovation Partnerships. Universal Display has licensed the technology from U-M and filed a patent application. Forrest has a financial interest in Universal Display Corp.