Making machine learning more useful to high-stakes decision makers

The U.S. Centers for Disease Control and Prevention estimates that one in seven children in the United States experienced abuse or neglect in the past year. Child protective services agencies around the nation receive a high number of reports each year (about 4.4 million in 2019) of alleged neglect or abuse. With so many cases, some agencies are implementing machine learning models to help child welfare specialists screen cases and determine which to recommend for further investigation.

But these models don’t do any good if the humans they are intended to help don’t understand or trust their outputs.

Researchers at MIT and elsewhere launched a research project to identify and tackle machine learning usability challenges in child welfare screening. In collaboration with a child welfare department in Colorado, the researchers studied how call screeners assess cases, with and without the help of machine learning predictions. Based on feedback from the call screeners, they designed a visual analytics tool that uses bar graphs to show how specific factors of a case contribute to the predicted risk that a child will be removed from their home within two years.

The researchers found that screeners are more interested in seeing how each factor, like the child’s age, influences a prediction, rather than understanding the computational basis of how the model works. Their results also show that even a simple model can cause confusion if its features are not described with straightforward language.

These findings could be applied to other high-risk fields where humans use machine learning models to help them make decisions, but lack data science experience, says senior author Kalyan Veeramachaneni, principal research scientist in the Laboratory for Information and Decision Systems (LIDS) and senior author of the paper.

“Researchers who study explainable AI, they often try to dig deeper into the model itself to explain what the model did. But a big takeaway from this project is that these domain experts don’t necessarily want to learn what machine learning actually does. They are more interested in understanding why the model is making a different prediction than what their intuition is saying, or what factors it is using to make this prediction. They want information that helps them reconcile their agreements or disagreements with the model, or confirms their intuition,” he says.

Co-authors include electrical engineering and computer science PhD student Alexandra Zytek, who is the lead author; postdoc Dongyu Liu; and Rhema Vaithianathan, professor of economics and director of the Center for Social Data Analytics at the Auckland University of Technology and professor of social data analytics at the University of Queensland. The research will be presented later this month at the IEEE Visualization Conference.

Real-world research

The researchers began the study more than two years ago by identifying seven factors that make a machine learning model less usable, including lack of trust in where predictions come from and disagreements between user opinions and the model’s output.

With these factors in mind, Zytek and Liu flew to Colorado in the winter of 2019 to learn firsthand from call screeners in a child welfare department. This department is implementing a machine learning system developed by Vaithianathan that generates a risk score for each report, predicting the likelihood the child will be removed from their home. That risk score is based on more than 100 demographic and historic factors, such as the parents’ ages and past court involvements.

“As you can imagine, just getting a number between one and 20 and being told to integrate this into your workflow can be a bit challenging,” Zytek says.

They observed how teams of screeners process cases in about 10 minutes and spend most of that time discussing the risk factors associated with the case. That inspired the researchers to develop a case-specific details interface, which shows how each factor influenced the overall risk score using color-coded, horizontal bar graphs that indicate the magnitude of the contribution in a positive or negative direction.

Based on observations and detailed interviews, the researchers built four additional interfaces that provide explanations of the model, including one that compares a current case to past cases with similar risk scores. Then they ran a series of user studies.

The studies revealed that more than 90 percent of the screeners found the case-specific details interface to be useful, and it generally increased their trust in the model’s predictions. On the other hand, the screeners did not like the case comparison interface. While the researchers thought this interface would increase trust in the model, screeners were concerned it could lead to decisions based on past cases rather than the current report.   

“The most interesting result to me was that, the features we showed them — the information that the model uses — had to be really interpretable to start. The model uses more than 100 different features in order to make its prediction, and a lot of those were a bit confusing,” Zytek says.

Keeping the screeners in the loop throughout the iterative process helped the researchers make decisions about what elements to include in the machine learning explanation tool, called Sibyl.

As they refined the Sibyl interfaces, the researchers were careful to consider how providing explanations could contribute to some cognitive biases, and even undermine screeners’ trust in the model.

For instance, since explanations are based on averages in a database of child abuse and neglect cases, having three past abuse referrals may actually decrease the risk score of a child, since averages in this database may be far higher. A screener may see that explanation and decide not to trust the model, even though it is working correctly, Zytek explains. And because humans tend to put more emphasis on recent information, the order in which the factors are listed could also influence decisions.

Improving interpretability

Based on feedback from call screeners, the researchers are working to tweak the explanation model so the features that it uses are easier to explain.

Moving forward, they plan to enhance the interfaces they’ve created based on additional feedback and then run a quantitative user study to track the effects on decision making with real cases. Once those evaluations are complete, they can prepare to deploy Sibyl, Zytek says.

“It was especially valuable to be able to work so actively with these screeners. We got to really understand the problems they faced. While we saw some reservations on their part, what we saw more of was excitement about how useful these explanations were in certain cases. That was really rewarding,” she says.

This work is supported, in part, by the National Science Foundation.

from ScienceBlog.com https://ift.tt/2ZskMkr

Making Martian rocket biofuel on Mars

Researchers at the Georgia Institute of Technology have developed a concept that would make Martian rocket fuel, on Mars, that could be used to launch future astronauts back to Earth.

The bioproduction process would use three resources native to the red planet: carbon dioxide, sunlight, and frozen water. It would also include transporting two microbes to Mars. The first would be cyanobacteria (algae), which would take CO₂ from the Martian atmosphere and use sunlight to create sugars. An engineered E. coli, which would be shipped from Earth, would convert those sugars into a Mars-specific propellant for rockets and other propulsion devices. The Martian propellant, which is called 2,3-butanediol, is currently in existence, can be created by E. coli, and, on Earth, is used to make polymers for production of rubber.

The process is outlined in a paper, “Designing the bioproduction of Martian rocket propellant via a biotechnology-enabled in situ resource utilization strategy,” published in the journal Nature Communications.

Rocket engines departing Mars are currently planned to be fueled by methane and liquid oxygen (LOX). Neither exist on the red planet, which means they would need to be transported from Earth to power a return spacecraft into Martian orbit. That transportation is expensive: ferrying the needed 30 tons of methane and LOX is estimated to cost around $8 billion. To reduce this cost, NASA has proposed using chemical catalysis to convert Martian carbon dioxide into LOX, though this still requires methane to be transported from Earth.

As an alternative, Georgia Tech researchers propose a biotechnology based in situ resource utilization (bio-ISRU) strategy that can produce both the propellant and LOX from CO₂. The researchers say making the propellant on Mars using Martian resources could help reduce mission cost. Additionally, the bio-ISRU process generates 44 tons of excess clean oxygen that could be set aside to use for other purposes, such as supporting human colonization.

“Carbon dioxide is one of the only resources available on Mars. Knowing that biology is especially good at converting CO₂ into useful products makes it a good fit for creating rocket fuel,” said Nick Kruyer, first author of the study and a recent Ph.D. recipient from Georgia Tech’s School of Chemical and Biomolecular Engineering (ChBE).

The paper outlines the process, which begins by ferrying plastic materials to Mars that would be assembled into photobioreactors occupying the size of four football fields. Cyanobacteria would grow in the reactors via photosynthesis (which requires carbon dioxide). Enzymes in a separate reactor would break down the cyanobacteria into sugars, which could be fed to the E. coli to produce the rocket propellant. The propellant would be separated from the E. coli fermentation broth using advanced separation methods.

The team’s research finds that the bio-ISRU strategy uses 32% less power (but weighs three times more) than the proposed chemically enabled strategy of shipping methane from Earth and producing oxygen via chemical catalysis.

Because the gravity on Mars is only a one-third of what is felt on Earth, the researchers were able to be creative as they thought of potential fuels.

“You need a lot less energy for lift-off on Mars, which gave us the flexibility to consider different chemicals that aren’t designed for rocket launch on Earth,” said Pamela Peralta-Yahya, a corresponding author of the study and an associate professor in the School of Chemistry & Biochemistry and ChBE who engineers microbes for the production of chemicals. “We started to consider ways to take advantage of the planet’s lower gravity and lack of oxygen to create solutions that aren’t relevant for Earth launches.”

“2,3-butanediol has been around for a long time, but we never thought about using it as a propellant. After analysis and preliminary experimental study, we realized that it is actually a good candidate,” said Wenting Sun, associate professor in the Daniel Guggenheim School of Aerospace Engineering, who works on fuels.

The Georgia Tech team spans campus. Chemists, chemical, mechanical, and aerospace engineers came together to develop the idea and process to create a viable Martian fuel. In addition to Kruyer, Peralta-Yahya, and Sun, the group included Caroline Genzale, a combustion expert and associate professor in the George W. Woodruff School of Mechanical Engineering, and Matthew Realff, professor and David Wang Sr. Fellow in ChBE, who is an expert in process synthesis and design.

The team is now looking to perform the biological and materials optimization identified to reduce the weight of the bio-ISRU process and make it lighter than the proposed chemical process. For example, improving the speed at which cyanobacteria grows on Mars will reduce the size of the photobioreactor, significantly lowering the payload required to transport the equipment from Earth.

“We also need to perform experiments to demonstrate that cyanobacteria can be grown in Martian conditions,” said Realff, who works on algae-based process analysis. “We need to consider the difference in the solar spectrum on Mars both due to the distance from the Sun and lack of atmospheric filtering of the sunlight. High ultraviolet levels could damage the cyanobacteria.”

The Georgia Tech team emphasizes that acknowledging the differences between the two planets is pivotal to developing efficient technologies for the ISRU production of fuel, food, and chemicals on Mars. It’s why they’re addressing the biological and materials challenges in the study in an effort to contribute to goal of future human presence beyond Earth.

“The Peralta-Yahya lab excels at finding new and exciting applications for synthetic biology and biotechnology, tackling exciting problems in sustainability,” added Kruyer. “Application of biotechnology on Mars is a perfect way to make use of limited available resources with minimal starting materials.”

The research was supported by a NASA Innovative Advanced Concepts (NIAC) Award.

Citation: Kruyer, et al. “Designing the bioproduction of Martian rocket propellant via a biotechnology-enabled in situ resource utilization strategy” Nature Communications. 10.1038/s41467-021-26393-7.

from ScienceBlog.com https://ift.tt/3bjbTMF

Potentially harmful industrial chemicals detected in US fast foods

Chicken nuggets, burritos and other popular items consumers buy from fast food outlets in the United States contain chemicals that are linked to a long list of serious health problems, according to a first-of-its-kind study published today.

Researchers at the George Washington University and their colleagues bought fast foods from popular outlets and found 10 of 11 potentially harmful chemicals in the samples, including phthalates, a group of chemicals that are used to make plastics soft and are known to disrupt the endocrine system. The research team also found other plasticizers, chemicals that are emerging as replacements to phthalates.

“We found phthalates and other plasticizers are widespread in prepared foods available at U.S. fast food chains, a finding that means many consumers are getting a side of potentially unhealthy chemicals along with their meal,” Lariah Edwards, lead author of the study and a postdoctoral scientist at GW, said. “Stronger regulations are needed to help keep these harmful chemicals out of the food supply.”

Previously, a GW research team led by Ami Zota, a professor of environmental and occupational health, looked at fast food consumption in a national survey and found people who reported eating more fast foods had higher levels of phthalates. No one has looked at the link between fast food and non-phthalate plasticizers, which are used in place of banned or restricted phthalates in food packaging and processing equipment.

In this study, Edwards, Zota and their colleagues purchased 64 fast food items from different restaurants and asked for three pairs of unused food handling gloves. The team tested food items and the gloves for 11 kinds of phthalates and plasticizers, finding that:

• 81% of the food samples studied contained a phthalate called DnBP and 70% contained DEHP. Both these chemicals have been linked in numerous studies to fertility and reproductive problems in humans. These phthalates can also increase risk for learning, attention, and behavioral disorders in childhood.
• 86% of the foods contained the replacement plasticizer known as DEHT, a chemical that needs further study to determine its impact on human health.
• Foods containing meats, such as cheeseburgers and chicken burritos, had higher levels of the chemicals studied.
• Chicken burritos and cheeseburgers had the highest levels of DEHT. The researchers noted that food handling gloves collected from the same restaurants also contained this chemical.
• Cheese pizzas had the lowest levels of most chemicals tested.

Phthalates and replacement plasticizers are chemicals used to make plastics soft and can migrate out of plastics into the food, which is ingested. Some sources of plastics include food handling gloves, industrial tubing, food conveyor belts and the outer packaging used to wrap fast food meals available in restaurants.

Previous research by Zota’s team suggests that people who eat food cooked at home have lower levels of these chemicals in their bodies, probably because home cooks do not use food handling gloves or plastic packaging. To avoid these industrial chemicals, consumers can switch to mostly home cooked meals, which are often healthier than fast food, Edwards said.

Both Edwards and Zota say their study suggests the need for greater scrutiny and regulation of chemicals used to make food. They point out that replacement plasticizers are increasingly used to replace banned or restricted phthalates yet the studies needed to show that they are safe have yet to be done.

The study also raises the concern that certain racial/minority groups may be disproportionately affected by these chemicals.

“Disadvantaged neighborhoods often have plenty of fast food outlets, but limited access to healthier foods like fruits and vegetables,” Zota said. “Additional research needs to be done to find out whether people living in such food deserts are at higher risk of exposure to these harmful chemicals.”

The study, “Phthalate and Novel Plasticizer Concentrations in Food Items from U.S. Fast Food Chains: A Preliminary Analysis,” was published in the Journal of Exposure Science and Environmental Epidemiology. This research was supported by the Passport Foundation, Forsythia Foundation and Marisla Foundation.

Read a fact sheet on the study here.

from ScienceBlog.com https://ift.tt/3pJ85fR

Cat’s meow: Robotic pet boosts mood, behavior and cognition in adults with dementia

Individuals with Alzheimer’s disease or related dementias (ADRD) often experience behavioral and psychological symptoms such as depression, aggression and anxiety. Frequently, these symptoms are treated with antipsychotics, antidepressants and benzodiazepines, which often have side effects.

While pet therapy is known to be a cost effective and therapeutic intervention for improving mood and behavior in older adults, little is known about pet therapy in adult day centers, despite logistical advantages such as socialization and group activities.

With the help of a cuddly and “furry” companion, researchers from Florida Atlantic University’s Christine E. Lynn College of Nursing tested the effectiveness of affordable, interactive robotic pet cats to improve mood, behavior and cognition in older adults with mild to moderate dementia. The non-pharmacological intervention took place over the course of 12 visits in an adult day center. Participants were informed that their pet was a robot and not a live animal. Each of them selected a name for their cat, which was fitted with a collar and a personalized nametag.

For the study, published in the journal Issues in Mental Health Nursing , researchers assessed mood and behavioral symptoms using the Alzheimer’s Disease and Related Dementias Mood Scale, the Observed Emotion Rating Scale and the Cornell Scale for Depression in Dementia. They also assessed cognition via the Mini Mental State Examination.

Results showed that intervention with a robotic pet cat improved all mood scores over time, with significant improvements in the Observed Emotion Rating Scale and the Cornell Scale of Depression in Dementia. More than half of the participants scored higher on the Mini Mental State Examination post-test than pretest, with slight to moderate improvement in attention/calculation, language and registration. Post-test scores on the Alzheimer’s Disease and Related Dementias Mood Scale were six points higher than pretest conditions.

Researchers frequently observed study participants smiling and talking to their robotic cats and expressing sentiments such as, “the cat is looking at me like someone who listens to me and loves me.” They believed that the robotic pet was responding to their statements through meowing, turning their head or blinking their eyes and that they were having a conversation with the pet. Several of the caregivers reported that their loved one had slept with the cat, held onto the cat when sitting or consistently played with the cat. One participant even slept with her robotic pet cat while she was hospitalized.

“Since there is no cure for dementia, our project offers a way to address symptoms naturally and without the use of pharmacological treatments, which may or may not be effective and have possible detrimental side effects,” said Bryanna Streit LaRose, D.N.P., A.P.R.N., lead author who conducted the study as a doctoral nursing student at FAU, together with co-authors Lisa Kirk Wiese, Ph.D., R.N., an associate professor and Streit LaRose’s faculty chair, and María de los Ángeles Ortega, D.N.P., A.P.R.N., a professor, director of FAU’s Louis and Anne Green Memory and Wellness Center and Streit LaRose’s community chair on the project, both within the Christine E. Lynn College of Nursing. “Our intervention was affordable, safe, and noninvasive.”

By using therapeutic pets instead of live pets, there was no concern about the safety of the pet, feeding them, taking them outside, or making sure they are up-to-date with their vaccines. In addition, there were no fears about participant safety due to possible pet aggression, allergies, tripping over them and the costs associated with caring for a live animal.

“In addition to improving mood, behaviors and cognition, these robotic pet cats provided our participants with an alternative way to express themselves,” said Wiese. “Importantly, improving overall mood and behavior in individuals with Alzheimer’s disease and related dementias may also improve quality of life for their caregivers and family members.”

The researchers also examined the relationship between the Mini Mental State Examination and subscale post-intervention scores of the Cornell Scale of Depression in Dementia, Observed Emotion Rating Scale and Alzheimer’s Disease and Related Dementias Mood Scale. They found multiple significant and strong correlations between the 11 subscales of the Alzheimer’s Disease and Related Dementias Mood Scale and Mini Mental State Examination following the intervention. Nine categories regarding pleasant mood/behavior correlated favorably with the Mini Mental State Examination score, indicating a relationship between positive mood/behavior and increased Mini Mental State Examination scores.

“In the United States, one in three older adults dies with Alzheimer’s disease or a related dementia and there is currently no cure for the rapidly growing burden,” said Safiya George, Ph.D., dean, Christine E. Lynn College of Nursing. “This therapeutic interactive pet intervention has proven to be a safe alternative method to improving mood and behavior in people with dementia who are attending an adult day center.”

Wiese and Ortega also are members of the FAU Institute for Human Health and Disease Intervention (I-HEALTH), created to advance health through pioneering research and practical applications.

FAU’s Christine E. Lynn College of Nursing received the 12 robotic pets for the project with assistance from an FAU Iota Xi Sigma grant and funding supplementation from Ageless Innovation.

from ScienceBlog.com https://ift.tt/3nt5mEK

Tiny pterosaurs dominated Cretaceous skies

The newly hatched juveniles of large and gigantic pterosaurs likely outcompeted other smaller adult pterosaur species to dominate the Late Cretaceous period around 100 million years ago, a new study led by researchers from the University of Portsmouth has found.

Pterosaurs were the flying cousins of dinosaurs – some were as large as a Spitfire fighter plane and others as small as a thrush.

During the Triassic and Jurassic periods, 252 – 145 million years ago, pterosaurs reached only modest sizes, but by the Late Cretaceous period many were giants – some with a wingspan of 10 metres or more.

It had been previously thought that the smaller species of pterosaurs were outcompeted by newly evolving birds, but this research has found that it was actually the babies of giant pterosaurs – known as flaplings – who overshadowed their small adult rivals.

Lead author, Roy Smith, from the University of Portsmouth’s School of the Environment, Geography and Geosciences, worked on the study with scientists from Africa and the UK. The international team comprised of experts from the universities of Cape Town, Leicester, Portsmouth and Casablanca.

He said: “Over the last 10 years or so, we’ve been doing fieldwork in Morocco’s Sahara Desert and have discovered over 400 specimens of pterosaurs from the Kem Kem Group, highly fossiliferous sandstones famous worldwide for the spectacular dinosaur Spinosaurus.

“We’d found some really big pterosaur jaws and also specimens that looked like smaller jaws – about the size of a fingernail – but these tiny pterosaur remains could have just been the tips of big jaws so we had to do some rigorous testing to find out if they were from a small species or from tiny juveniles of large and giant pterosaurs.”

Roy and his colleagues examined five small jaw fragments and a neck vertebra using sophisticated microscope techniques to determine the age of the individual when the animal died.

Co-investigator, Anusuya Chinsamy-Turan, from the University of Cape Town in South Africa, is a world expert on the bone microstructure (histology) of pterosaurs and dinosaurs. She said: “By looking at the paper-thin section of the bones under a microscope, I could tell that they were from juveniles as the bone was fast growing and didn’t have many growth lines.

“We also examined the surface of the bones and found they had a rippled texture. This was further evidence they were the bones of immature individuals as mature pterosaur bones have an incredibly smooth surface once they are fully formed.”

The researchers also inspected the jaws and found that the number of tiny holes where nerves come to the surface for sensing their prey, known as ‘foramina’, were the same in the small jaws and the big jaws.

“This was more proof we were looking at the jaws of juveniles because if the specimens were just the tip of a jaw, there would be a fraction of the number of foramina,” said Roy.

Recent findings have suggested that hatchling pterosaurs could fly soon after hatching so they were quickly independent.

Professor David Martill of the University of Portsmouth said: “What really surprised me about this research is that the feeding ecology of these magnificent flying animals is more like that of crocodiles than of birds.

“With birds, there will be perhaps 10 different species of different sizes alongside a river bank – think kingfisher, little bittern, little egret, heron, goliath heron or stork for a large European river. There are several species all feeding on slightly different prey. This is called niche partitioning.

“Crocodiles on the other hand are much less diverse. On the river Nile, hatchling crocodiles feed on insects, and as they grow they change their diet to small fish, then larger fish and then small mammals, until a big adult Nile croc is capable of taking a zebra.

“There are lots of different feeding niches, but they are all occupied by one species at different stages of its life history. It seems that pterosaurs did something rather similar, occupying different niches as they grew – a much more reptilian rather than avian life strategy.

“It’s likely that the juvenile pterosaurs were feeding on small prey such as freshwater insects, tiny fishes and amphibians. As they grew they could take larger fishes – and who knows – the biggest pterosaurs might have been capable of eating small species of dinosaurs, or the young of large dinosaur species.”

The pterosaur specimens are part of the collections of Casablanca Hassan II University and the paper is published in Cretaceous Research.

from ScienceBlog.com https://ift.tt/3BjXoCO

Giving autonomous vehicles the safety ‘green light’

An ethical framework developed by government, road users and other stakeholders must steer the introduction of new road rules for connected and automated vehicles (CAVs), international experts say.

They warn that strictly forbidding CAVs of various kinds to break existing traffic rules may hamper road safety, contrary to what most people may claim. However, this requires close scrutiny so these high-tech vehicles can meet their potential to reduce road casualties.

“While they promise to minimise road safety risk, CAVs like hybrid AI systems can still create collision risk due to technological and human-system interaction issues, the complexity of traffic, interaction with other road users and vulnerable road users,” says UK transport consultant Professor Nick Reed, from Reed Mobility, in a new paper in Ethics and Information Technology.

“Ethical goal functions for CAVs would enable developers to optimise driving behaviours for safety under conditions of uncertainty while allowing for differentiation of products according to brand values.”

This part is important since it does not state that all vehicle brands should drive in exactly the same manner, which still allows brand differentiation, researchers say.

Around the world, transport services are already putting CAVs, including driverless cars, on the road to deliver new services and freight options to improve road safety, alleviate congestion and increase drive comfort and transport system productivity.

A recent European Commission report recommended CAVs may have to break strict traffic rules to minimise road safety risk and to operate with appropriate transparency.

Professor Reed, Flinders University Dean of Law Professor Tania Leiman, and other European experts in the field of autonomous vehicle safety the key recommendation from the EC (Bonnefon et al, 2020) highlights the need to legislate for CAVs in various traffic and environmental conditions to exercise the equivalent of human discretionary behaviours.

This is complicated even further where there are variations in laws across different countries and regions, and cars are designed or built in one country but used in another, says Flinders Professor Leiman, from the College of Business, Government and Law.

“An automated system that has ‘deduced’ driving behaviour from training examples cannot ‘explain’ or ‘justify’ its decisions or actions in a dangerous encounter,” she says.

“This may be a problem if a manufacturer is required to explain specific behaviour in case of an incident or where civil or criminal liability is disputed.”

Speeding and mounting the curb to avoid collision are also evaluated as case studies in the research paper, with the idea that ethical goals should be established by extensive public consultation and deliberation to make them publicly acceptable and understood.

The researchers say it will be critical that there is a standardised framework to enable vehicles travelling from one jurisdiction into the next to update their road rules to make driving standards safe, predictable, reasonable, uniform, comfortable and explainable – both for drivers, manufacturers and all road users.

“We suggest responsibility for creating the framework of CAV ethical goal functions should sit with an appropriate international body, for example, the Global Forum for Road Traffic Safety of the UNECE, and relevant individual country agencies such as the Department of Transport,” says co-author on the paper Dr Leon Kester, senior research scientist at TNO, The Netherlands.

“Once an ethical goal function has been agreed and enacted by legislators, CAV systems could be designed in such a way that they optimise with the highest utility for road users within predefined boundaries without having a predefined set of infinite scenarios and precise definitions on what to do,” Dr Kester says.

“Also, we have to organise a socio-technological feedback loop where things can be evaluated and changed if we feel it is no longer according to our societal goals.”

The article, Ethics of automated vehicles: breaking traffic rules for road safety (2021) by Nick Reed, Tania Leiman, Paula Palade, Marieke Martens and Leon Kester has been published in Ethics and Information Technology DOI: 10.1007/s10676-021-09614-x

from ScienceBlog.com https://ift.tt/3pCAzbk

Of balding mice and men and women

A newly discovered cause of balding in aging male mice could reveal a cause of hair loss in men and women as well, reports a study from Northwestern Medicine scientists. The findings provide new insight into how hair and tissues age.

The study, published in Nature Aging in October, shows as hair stem cells age, they lose the stickiness that keeps them lodged inside the hair follicle. As their adhesiveness wanes, the stem cells escape from their location, called the bulge, into the dermis. Outside their delicate microenvironment, they generally can’t survive.

“The result is fewer and fewer stem cells in the hair follicle to produce hair,” said lead author Rui Yi, the Paul E. Steiner Research Professor of Pathology at Northwestern University Feinberg School of Medicine. “This results in thinning hair and ultimately baldness during aging.”

The finding could likely apply to older men and women with thinning hair because there are many similarities between mice and humans in hair and stem cells, Yi said.

This is the first time hair follicle aging has been tracked in live animals, allowing scientists a real-time cellular view of the aging process.

Scientists also discovered two key genes responsible for enhancing adhesiveness of the stem cells. In a current study, they are trying to reinstate these genes to see if that will reverse hair loss.

It’s always life and death for hair follicles

Our hair follicle goes through cycles of life and death. During these normal cycles, a large number of stem cells stay permanently lodged in the stem cell compartment of hair follicles to keep producing hair follicle cells. In this study, scientists discovered what happens to these stem cells due to aging, resulting in thinning hair and balding.

How the study advances research

“We believe this stem cell escape mechanism has never been reported before, because nobody could track the aging process in live animals,” Yi said.

Scientists knew hair follicles become miniaturized during aging. But how it happened wasn’t clear. Many scientists thought it was due to cell death or the inability of cells to divide as they age.

“We discovered, at least in part, it is due to hair follicle stem cells migrating away from their niche,” Yi said. “Cell death also occurs during our observation. So, our discovery doesn’t dispute existing theories but provides a new mechanism.”

How the study worked

Scientists labeled hair follicle cells, including stem cells, with green fluorescent protein in live mice and used a long, wavelength laser to observe hair follicle cells during aging. They observed the same hair follicle repeatedly for many days (in one case, they observed one hair follicle for 26 days and saw the entire process of hair follicle degradation). They saw signs of unusual cell escape.

Next, they compared gene expression levels between young and old animals in follicle stem cells. They found less expression of genes responsible for adhesion in old hair follicle stem cells.

Researchers then identified a special group of genes which may regulate these cell adhesion genes. They genetically knocked out these two genes, FOXC1 and NFATC1, in mutant animals. The result: rapid progress of hair loss starting at four months. Within 12 to 16 months, these mice became completely bald. Finally, researchers used the live imaging to observe stem cell escape in these mutant mice and captured the action of stem cells migrating away from stem cell niche.

Other Northwestern authors are Chi Zhang (a visiting student), Dongmei Wang, Jingjing Wang and Dr. Tsutomu Kume.

The study was supported by grants AR059697, AR066703 and AR071435 from the National Institute of Arthritis, Musculoskeletal and Skin Diseases and F99CA253738 from the National Cancer Institute of the National Institutes of Health.

from ScienceBlog.com https://ift.tt/3GqoAnc