It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, August 20, 2022
E-learning training program better than no training for nurse knowledge and skills, researchers find
Adults self-report their pain on a one to 10 numerical score, while children can point to an equivalent face scale — from a green smiling face to a red crying face — to indicate their pain. Newborns, however, cannot say a number or point to a face, leaving it up to their caregivers to identify and evaluate any pain they may be in. Until the turn of this century, a significant number of clinicians did not recognize that neonates could even experience pain, resulting in infrequent, nonstandard training for medical workers. Now, researchers are reporting that a flexible e-learning program improves neonate pain management knowledge and skills for nurses.
They published the results of their randomized, controlled study on July 30 in Pain Management Nursing.
“Continuing education is essential to maintain and increase nurses’ proficiency in neonatal pain assessment and treatment,” said corresponding author Mio Ozawa, associate professor in the Graduate School of Biomedical and Health Science at Hiroshima University. “Our results showed that e-learning programs were more effective as compared to no training.”
The researchers randomly divided recruited certified neonatal intensive care nurses from across Japan into two groups. One group received four weeks of online training in pain measurement, using structured scales designed for pre-term newborns, called the e-Pain Management of Neonates program. The other group did not receive training. Participants in both groups took a pre- and post-test. While there were no differences in knowledge or skill in the pre-test scores between the two groups, the e-learning group scored higher for both knowledge and skill.
The research builds on a prior pilot study, in which 52 nurses completed the e-learning program and improved their test scores. However, without a control group for comparison, the evidence was not sufficient to illustrate the intervention’s effectiveness, according to Ozawa.
“In the current study, we tested the e-learning program with a randomized control trial, a more powerful research design than used with the pilot study,” Ozawa said. “To the best of our knowledge, this is the first such trial that investigates the effects of e-learning on the knowledge and skill in neonatal pain measurement for certified nurses across NICUs across multiple hospitals.”
The e-learning program consists of four modules, each of which takes about 15 minutes to complete. Participants could save their progress and return at any point, as well as review as many times as they wanted. While more nurses were more likely to access the program in the middle of the day or late at night on a weekday, participants still accessed the program at odd hours and over the weekend.
“An e-learning program may be a more efficient method as nurses can participate in the program at their own convenience,” Ozawa said. “In comparison with other health care professionals, NICU nurses stay at the bedside of newborns for the longest time to provide care, including invasive procedures. It is vital for nurses to be educated and train in using the neonatal pain management scale.”
Ozawa emphasized that while this study did not demonstrate e-learning’s superiority as a learning method compared to traditional approaches, such as in-person training, it does indicate that e-learning can improve skills and knowledge.
“Learning in this program would allow nurses to acquire knowledge and skills concerning
newborn pain, which is preferred over no education,” Ozawa said. “Further research is needed to determine how nurses’ training through e-learning programs is related to patient outcomes, such as more frequent pain assessment of infants by nurses and improved pain management.”
Other contributors include Kotomi Yamashita, assistant professor, Graduate School of Health Sciences, Okayama University, and Reo Kawano, associate professor, Clinical Research Center in Hiroshima, Hiroshima University Hospital.
The Japan Society for the Promotion of Science supported this research.
IMAGE: PENN STATE RESEARCHERS, INCLUDING PRINCIPAL INVESTIGATOR AMIR SHEIKHI, ASSISTANT PROFESSOR OF CHEMICAL ENGINEERING, IMPROVED UPON PREVIOUS WORK AND EXTRACTED LARGER SAMPLE SIZES OF NEODYMIUM FROM LESS CONCENTRATED SOLUTIONS.view more
CREDIT: CREDIT: KELBY HOCHREITHER/PENN STATE
What do corncobs and tomato peels have to do with electronics? They both can be used to salvage valuable rare earth elements, like neodymium, from electronic waste. Penn State researchers used micro- and nanoparticles created from the organic materials to capture rare earth elements from aqueous solutions.
“Waste products like corncobs, wood pulp, cotton and tomato peels often end up in landfills or in compost,” said corresponding author Amir Sheikhi, assistant professor of chemical engineering. “We wanted to transform these waste products into micro- or nanoscale particles capable of extracting rare earth elements from electronic waste.”
Rare earth metals are used to manufacture strong magnets used in motors for electric and hybrid cars, loudspeakers, headphones, computers, wind turbines, TV screens and more. However, mining these metals proves challenging and environmentally costly, according to Sheikhi, as large land areas are required to mine even small amounts of the metals. Instead, efforts have turned to recycling the metals from electronic waste items like old computers or circuit boards.
The challenge lies in efficiently separating the metals from refuse, Sheikhi said.
“Using the organic materials as a platform, we created highly functional micro- and nanoparticles that can attach to metals like neodymium and separate them from the fluid that surrounds them,” Sheikhi said. “Via electrostatic interactions, the negatively-charged micro- and nano-scale materials bind to positively-charged neodymium ions, separating them.”
To prepare the experiment, Sheikhi’s team ground up tomato peel and corncob and cut wood pulp and cotton paper into small, thin pieces and soaked them in water. Then, they chemically reacted these materials in a controlled fashion to disintegrate them into three distinct fractions of functional materials: microproducts, nanoparticles and solubilized biopolymers. Adding the microproducts or nanoparticles to neodymium solutions triggered the separation process, resulting in the capture of neodymium samples.
In this most recent paper, Sheikhi improved upon the separation process demonstrated in previous workand extracted larger sample sizes of neodymium from less concentrated solutions.
Sheikhi plans to extend his separation mechanism into real-world scenarios and partner with interested industries to further test the process.
“In the near future, we want to test our process on realistic industrial samples,” Sheikhi said.
“We also hope to tune the selectivity of the materials toward other rare earth elements and precious metals, like gold and silver, to be able to separate those from waste products as well.”
In addition to Sheikhi, Mica Pitcher, Penn State doctoral student in chemistry and first author on the paper; Breanna Huntington, Penn State undergraduate student in agricultural and biological engineering; and Juliana Dominick, Penn State undergraduate student in biomedical engineering, contributed to the paper.
Penn State supported this work.
CAPTION
After soaking the materials in water (as shown in middle column), Penn State researchers chemically reacted shredded wood pulp, cotton paper and ground corncob and tomato peels to convert them into microproducts, nanoparticles and solubilized biopolymers (third column). Adding these microproducts or nanoparticles to solutions containing the rare earth element neodymium triggered the separation process, allowing for capture of the neodymium.
IMAGE: SAMANTHA ANDRZEJACZEK, A POSTDOCTORAL RESEARCH FELLOW AT STANFORD’S HOPKINS MARINE STATION, (SECOND FROM RIGHT) TAGGING A TIGER SHARK.view more
CREDIT: ALEX KYDD
Using sophisticated electronic tags, scientists have assembled a large biologging dataset to garner comparative insights on how sharks, rays, and skates – also known as “elasmobranchs” – use the ocean depths. While some species spend their entire lives in shallow waters close to our shores on the continental shelf, others plunge hundreds of meters or more off the slope waters into the twilight zone, beyond where sunlight penetrates. This new understanding of how elasmobranchs use the ocean will enable policymakers and resource managers the opportunity to examine the threats these animals face, and guide future management and conservation plans.
A study published Aug. 19 in Science Advances, led by Stanford University and ZSL (Zoological Society of London) researchers, is the largest global investigation of where and when a diverse group of elasmobranchs move vertically. A team of 171 researchers from 135 institutions across 25 countries brought together two decades of data from satellite and archival tags that remotely tracked the movements and behaviors of 38 species in oceans across the globe.
“For the first time, we have a standardized, global database that we used to fill important knowledge gaps about the diving behaviors of sharks and rays,” said Samantha Andrzejaczek, co-lead author of the study and a postdoctoral research fellow at the Hopkins Marine Station of Stanford University. “This will enable better understanding of what fisheries interact with elasmobranchs and how to improve management of many of these long-lived animals.”
Movement in three dimensions
Scientists already have a wealth of movement data about many marine species that inhabit the near-surface spaces of the coastal ocean. Drones, scuba divers, and other methods, for example, survey marine communities and populations to a depth of about 50 meters, but animal movement in three dimensions, especially in the deeper, vertical spaces of the ocean, is far less understood.
“Sharks and rays are iconic but threatened ocean species. Key to their effective management is an understanding of their basic ecology,” said David Curnick, head of the Ocean Predator Lab at ZSL and co-lead author of the paper. “Yet, for many species, we know relatively little about their fundamental behavior, and what we do know is often restricted to what we can observe in surface waters.”
Over the past 20 years, a variety of electronic tags have come of age that provide the opportunity to tag numerous elasmobranch species. Scientists at Stanford have been at the forefront of biologging tag development and applying these technologies on sharks and rays.
One of the common vertical movements among elasmobranchs appears to match up with the ocean’s diel (twice a day) vertical migration. At daybreak, tiny fish and invertebrates – followed by the animals that prey on them – begin migrating from the bright, uppermost ocean layer to the relative safety of darker, deeper water. At night, they return to the surface to feed.
“We think that sharks and rays in their diel migrations are following food resources up and down the water column,” said Andrzejaczek.
The study found that about one-third of species frequently dive to depths where the water is cold, often low on oxygen due to biological activity related to productivity, and visibility is limited. Sensor records show that white sharks (Carcharodon carcharias) dive deeper than 1200 meters while whale sharks (Rhincodon typus) have reached 1896 meters, which is near the pressure limit of 2000 meters for today’s sensors.
“Deep divers might be looking for food in deeper water or avoiding hunters themselves as potential prey,” said Andrzejaczek. “Some sharks and rays are small, and some of the biggest sharks and rays will feed on them. We found that 13 species had individuals that dive to more than 1000 meters, which is extremely deep.” Some may require cooling-off periods while at depth. “When large sharks spend too long in the warm surface waters, they may have to dive to cool down, a form of behavioral thermoregulation,” she added.
The researchers also identified overlaps among species in the same vertical spaces. Whale sharks, tiger sharks, and oceanic manta rays showed strikingly similar vertical distributions, although they have very different evolutionary histories. Predator-and-prey relationships likely drive this proximity. “The oceanic manta ray and whale shark both feed on plankton, and the tiger shark has been known to predate on both those species,” said Andrzejaczek.
A foundation for future management
The photic zone or epipelagic – the ocean region receiving sunlight – stretches from the surface to about 200 meters and can potentially be a dangerous area for elasmobranchs. That is where they are most likely to be exposed to fishing gear as either target species or as bycatch. Of the 38 species in the study, researchers found that 26 spent more than 95% of their time in the top 250 meters of the water column.
More than one-third of all sharks and rays are threatened with extinction, according to the IUCN Red List of Threatened Species.
“These data provide the foundation for future management of global elasmobranch resources, and it has taken a team of scientists thousands of hours tagging and tracking the sharks with global satellite and biologging systems to make this possibility happen,” said Barbara Block, the Prothro Professor of Marine Sciences at Stanford, whose tagging programs such as TOPP, contributed 25% of the data set.
Understanding how elasmobranchs use vertical habitats is crucial to understanding their current and future ecological roles in the ocean and their risks to various threats. Scientists could utilize this and future databases to investigate how changing ocean temperature and oxygen levels may influence species’ distributions and create new conditions and threats.
“Human beings are unaccustomed to thinking of habitat in the vertical dimension,” said Andrzejaczek. “We hope this study can make people realize that we need management strategies that incorporate this overlooked dimension of elasmobranch behavior. For example, we could use these data to better understand how sharks and human fisheries interact.”
This three-year study brought together data from increasingly sophisticated and more accurate tags with sensitive sensors that can withstand the rigors of the environment while riding along on a shark or ray and function in deep water, as well as improved analytical tools to incorporate different types of movement data. The key ingredient has been cooperation among biologging scientists from around the world.
“Large-scale scientific studies like this one are not possible without a monumental collaborative effort,” said Curnick. “We reconcile the collective knowledge and expertise of researchers from around the world. The result is far greater than any one researcher or institution could achieve on their own.”
This work was led by Stanford University and the Zoological Society of London. Additional Stanford co-authors include graduate student Maurice Goodman; research data analyst Mike Castleton; research scientist Jonathan Dale; and researcher Robert Schallert. Former Stanford graduate students and postdoctoral scholars George Shillinger, Andre Boustany, Kevin Weng, Taylor Chapple, and Sal Jorgensen are also co-authors. Block is also a professor of biology and a senior fellow at the Stanford Woods Institute for the Environment.
This research was funded by the Bertarelli Foundation, the Moore Foundation, the Sloan Foundation, Instituto Politecnico Nacional, the Darwin Initiative, the Georgia Aquarium, the Rolex Awards for Enterprise, and the Whitley Fund for Nature.
Conflict between shark populations and fishing communities is reported to be rising within one of the world’s first shark sanctuaries.
Fishers say increasing shark populations have reduced catch and income, according to Newcastle University research.
Shark populations around the world are in rapid decline, with 24% of all shark species at risk of extinction. While efforts to protect sharks vary, 17 countries have declared their waters as ‘shark sanctuaries’, typically banning commercial shark fishing. In some regions this has led to increasing reports of negative fisher-shark interactions, particularly depredation – when a shark preys on a fishers catch.
New research led by Newcastle University presents a unique overview of fisher-shark interactions, focusing on fisher perspectives within the Maldives shark sanctuary. Their results show that most fishers reported an increase in shark depredation, with substantial catch and income losses (>21%) reported by reef fishers. They also found that those experiencing greater losses due to depredation showed reduced support for the Maldives shark sanctuary.
Mapping exercises with fishers and underwater camera stations (BRUVS) were used to identify areas of high shark abundance and ‘conflict hotspots’ where sharks and fishing activity overlapped. This provided valuable information as to why fishers believe depredation is increasing despite stable populations in the region.
Published in the journal Conservation Letters, the findings suggest that management of shark depredation needs to be addressed sensitively to avoid negative implications for fisher welfare and shark population recovery.
Study lead author, Dr Danielle Robinson, of Newcastle University’s School of Natural and Environmental Sciences, said: “The study highlights the importance of more inclusive approaches to help us understand and manage depredation conflicts. Research and conservation frameworks tend to focus on commercial fisheries due to their economic value, yet our findings highlight the urgent need to consider and manage negative perceptions of small-scale fisheries when developing policy solutions”.
“Fishers and sharks are competing for the same thing – fish – and I think a really exciting aspect of this study is that we were able to collect spatial data from fisher interviews and underwater cameras (BRUVS) at the same spatial scale to map areas with high conflict potential”.
The study is one of few in the field to shed light on the socio-economic costs of shark sanctuaries and the importance of accounting for diverging perceptions among fisher groups.
Findings raise important issues relating to trade-offs between policies to protect biodiversity and those related to human welfare.
As the important participants and decision makers in agricultural production, smallholders play a crucial role in food production. Smallholders’ low level of technology awareness and capacity leads to problems such as the insufficient technology adoption. Coupled with their poor risk tolerance and lack of trust in new technologies, makes them lack of the motivation to actively adopt green production technologies, which seriously hinders the green transformation of agriculture. What should be done to promote smallholders’adoption of green production technologies proactively? The existence of multiple socialized services and agricultural technology diffusion systems offers the possibility for this.
Existing production agriculture extension is divided into two distinct approaches: top-down and bottom-up modes. The former emphasizes scientists innovate technologies in laboratory and instill them into smallholders through organizations such as agricultural technology extension service centers (ATESC). This mode ignores smallholders’ motivation, and trust issues arising from the uneven quality of services became a crucial barrier to technology diffusion. The latter mode is mainly based on smallholders’ production technologies demand and socialized services, through participatory technological innovation, resulting in localized technologies and diffusion. However, because this approach requires high time and place for scientists and smallholders to learn together, it is less controllable and runs the risk of being a formality. We believe that an intimate partnership with smallholders is needed, while empowering them through zero-distance socialized services and stimulating their willingness to actively adopt green production technologies, to form a long-term mechanism for sustainable green production. A good example of this is the Science and Technology Backyard (STB) founded by the team of Prof. Fusuo Zhang of China Agricultural University. The teachers and graduate students of the STB are permanently rooted in the front line of rural production, forming a typical bottom-up approach to technological innovation through continuous interaction, learning and co-innovation with smallholders. This mode solves the problem of adaptive technological innovation and effectively promotes the application of green production technologies at different scale scales, but how to gradually realize the diffusion of technological innovation from the pilot areas to the regional level, is still unclear.
Therefore, the authors take the Wangzhuang STB in Quzhou, Hebei, China, as the research object, and explore how STB empower smallholders through participatory technology innovation and build their continuous trust through a socialized services mode with multi-entity participation, and promote the technology of participatory innovation in a collaborative, tree-shaped and jump-start diffusion modes promotes the diffusion of participatory technology innovation to different scales, such as farmers, villages and counties. This kind of technology diffusion based on STB empowers smallholders through zero-distance socialized services, and effectively solves the problem from technology innovation at the point to technology diffusion in the region, which is a highly applicable and practical technology innovation and diffusion mode and an effective way to promote the sustainable adoption of green production technologies by smallholders.
Yajuan LI, Qianni HUANG. SMALLHOLDER ADOPTION OF GREEN PRODUCTION TECHNOLOGIES ON THE NORTH CHINA PLAIN: EVIDENCE FROM SCIENCE AND TECHNOLOGY BACKYARDS. Frontiers of Agricultural Science and Engineering [Published Online] https://doi.org/10.15302/J-FASE-2022461
About Frontiers of Agricultural Science and Engineering
Frontiers of Agricultural Science and Engineering (FASE) is an international journal, which is aimed to publish papers that advance the understanding of scientific, technological/engineering, socioeconomic, institutional/policy and management factors that drive current and future agricultural productivity and sustainability. Our goal is to use FASE as a platform to foster scientific information flow, stimulate transdisciplinary inquiries that have strong multi-disciplinary connections, and cultivate research and idea exchanges that address agricultural sustainability challenges regionally and globally.
FASE is an open-access journal published quarterly with no page charges. Contributions may include cutting-edge research, science news, commentaries, perspectives, or reviews. In addition to publishing regular review and research articles, the journal also publishes 'Hot Topic’issues that focus on strategically selected subject matter of high impact, or emerging concerns to address future agricultural development pathways at regional and global levels, and are guest-edited by scientists in their areas of research. Proposals for special issues are welcome and can be submitted any time.
Due to a lack of publicly available data, understanding what products medical cannabis patients use for various conditions has mostly come from survey responses. In a new study, USC Schaeffer Center researchers established a clearer picture by analyzing point-of-sale data from nearly 17,000 patients who made more than 80,000 purchases as part of the New York state medical cannabis program.
The researchers found considerable variation in the products chosen for most medical conditions, and high variability in labeled doses of THC.
“While the medical cannabis market is not new, there is still relatively little research on patient purchasing behavior,” says Alexandra Kritikos, a postdoctoral research fellow in the USC Schaeffer Center and the USC Institute for Addiction Science. “Unfortunately, our analysis suggests that patients may not be getting consistent guidance from clinicians and pharmacists and, in many disease areas, there seems to be a lack of clear clinical data on appropriate dosing.”
The results, published in JAMA Network Open, rely on purchases made between 2016 and 2019 when cannabis flower and edibles could not be sold in the medical market. Cannabis card holders could purchase vape cartridges and pens, capsules and tablets, tinctures, lotions and suppositories.
Medical cannabis users purchase a range of products with varying potencies
Since its inception in 2014, New York’s medical cannabis program has grown to 150,000 participants, making it one of the largest in the nation.
Using data from an integrated single system of dispensaries, the researchers found that the top three conditions patients recorded on their medical card were chronic pain (52%), neuropathy (22%) and cancer (13%). In addition to a qualifying condition, patients also needed a qualifying symptom to register. The top qualifying symptoms were severe pain (82%), severe muscle spasms (21%) and severe nausea (8%).
Vaporizers were the most popular product purchased (40%), followed by tinctures (38%) and tablets (22%). In terms of potency, the majority of products purchased (52%) were high-THC, low-CBD products. High- THC products contained between 2 and 10 mg of THC per dose, depending on the product.
Given this variation, when patients chose different products, they presumably favored different dosing. For example, 41% of patients with chronic pain preferred a high-THC vaporizer, which delivered 2 mg of THC/0.1 mg of CBD per dose, while 33% of chronic pain patients chose tinctures and 25% chose tablets, both of which delivered 10 mg of THC per dose. Another quarter of chronic pain patients chose a product containing 5 mg of both THC and CBD.
In contrast, the majority of patients suffering from cancer, HIV/AIDS and epilepsy purchased the same product, suggesting similar dosing.
Physicians need to take a more active role in patients using medical cannabis products
Earlier research found that electronic medical records frequently underreport the number of medical cannabis users. Combined with findings in the new Schaeffer Center study, the researchers suggest improving medical guidance and oversight of dosing.
“We suspect the lack of clinical guidelines on dosing of cannabinoids for particular medical conditions has made medical providers uncomfortable talking to their patients about their medical cannabis use,” says Rosalie Liccardo Pacula, senior author on both studies. “It is imperative that this change, as drug interactions with other prescribed medications are likely but impossible to identify if medical cannabis use is not considered or recorded in the medical record.” Pacula is a senior fellow at the Schaeffer Center and the Elizabeth Garrett Chair in Health Policy, Economics & Law at the USC Price School of Public Policy.
Pacula and Kritikos hope that their study provides a basis for conversations between providers and patients about cannabis use, including dosing levels.
Calls for caps in the recreational market will not limit access for medical cannabis patients
According to the labeled dosing, none of the most popular products analyzed for any of the conditions had dosing of more than 10 mg of THC, something policymakers should consider, say the researchers.
“We’ve seen the industry and media make the claim that putting caps on potency would limit access to necessary medicine,” Pacula says. “But our research in New York state suggests that medical cannabis users are consuming products that are less potent than what recreational users take.”
A white paper published by the Schaeffer Center in July discussed how policymakers could legalize recreational cannabis while still putting regulations in place that prioritize public health.
Characterization of Cannabis Products Purchased for Medical Use in New York State
ARTICLE PUBLICATION DATE
19-Aug-2022
COI STATEMENT
Dr Kritikos reported receiving grants from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) during the conduct of the study and being an unpaid consultant for the Massachusetts Cannabis Control Commission on a legislative report. Dr Pacula reported receiving personal fees from the Centers for Disease Control & Prevention and serving on their Board of Scholars; receiving grants from the NIAAA and the National Institute on Drug Abuse; and receiving reimbursement for travel from the National Academies of Sciences, Engineering, and Medicine (NASEM); serving on a NASEM committee regarding CARA spending on opioids outside the submitted work; and serving on dissertation committees with the medical director of Columbia Care LLC, the medical cannabis company that provided access to the data. No other disclosures were reported.
Study: New model for predicting belief change
SANTA FE INSTITUTE
IMAGE: BELIEF NETWORKS AND DEVELOPMENT OF INTERDEPENDENCE OVER MEASUREMENTS.view more
CREDIT: JONAS DALEGE AND TAMARA VAN DER DOES
A new kind of predictive network model could help determine which people will change their minds about contentious scientific issues when presented with evidence-based information.
A study in Science Advances presents a framework to accurately predict if a person will change their opinion about a certain topic. The approach estimates the amount of dissonance, or mental discomfort, a person has from holding conflicting beliefs about a topic.
Santa Fe Institute Postdoctoral Fellows Jonas Dalege and Tamara van der Does built on previous efforts to model belief change by integrating both moral and social beliefs into a statistical physics framework of 20 interacting beliefs.
They then used this cognitive network model to predict how the beliefs of a group of nearly 1,000 people, who were at least somewhat skeptical about the efficacy of genetically modified foods and childhood vaccines, would change as the result of an educational intervention.
Study participants were shown a message about the scientific consensus on genetic modification and vaccines. Those who began the study with a lot of dissonance in their interwoven network of beliefs were more likely to change their beliefs after viewing the messaging, but not necessarily in accordance with the message. On the other hand, people with little dissonance showed little change following the intervention.
“For example, if you believe that scientists are inherently trustworthy, but your family and friends tell you that vaccines are unsafe, this is going to create some dissonance in your mind,” van der Does says. “We found that if you were already kind of anti-GM foods or vaccines to begin with, you would just move more towards that direction when presented with new information even if that wasn’t the intention of the intervention.”
While still in an early stage, the research could ultimately have important implications for communicating scientific, evidence-based information to the public.
“On the one hand you might want to target people who have some dissonance in their beliefs, but at the same time this also creates some danger that they will reduce their dissonance in a way that you didn’t want them to,” Dalege says. “Moving forward, we want to expand this research to see if we can learn more about why people take certain paths to reduce their dissonance.”
IMAGE: THIS RESEARCH DISCOVERED THAT OPOSSUM HEARTS ARE ABLE TO REGENERATE 2 WEEKS AFTER BIRTH BECAUSE AMPK ACTIVITY WAS STILL INACTIVE. APPLYING THIS KNOWLEDGE TO MICE, RESEARCHERS WERE ABLE TO PROLONG THE PERIOD OF TIME THAT MOUSE HEARTS CAN REGENERATE AFTER BIRTH BY BLOCKING AMPK ACTIVITY.view more
CREDIT: RIKEN
Wataru Kimura and colleagues at the RIKEN Center for Biosystems Dynamics Research (BDR) in Japan have discovered how the hearts of newborn marsupials retain the ability to regenerate for several weeks. Using this knowledge, the team was able to repair mouse hearts that were damaged a week after birth. The findings, published in the scientific journal Circulation, are expected to contribute to the development of regenerative heart medicines.
Heart disease is a leading cause of human death and is associated with numerous other secondary illnesses. For humans and other mammals, damaged heart muscle—such as occurs after a heart attack—cannot be naturally repaired because matured heart-muscle cells do not regenerate. As with all tissue regeneration, heart repair requires the birth of new cells, which can only happen through the process of cell division, when one cell becomes two. In most mammalian hearts, muscle-cell division remains possible just after birth, but disappears quickly after a couple days.
However, unlike other mammals, marsupials like kangaroos and koalas are born in an underdeveloped state and many of their internal organs continue to grow after birth, including their hearts. However, not much is known about their capacity for heart regeneration. The team at RIKEN BDR hypothesized that this post-natal heart growth is possible because marsupial heart-muscle cells retain the ability to divide, and that this would allow their hearts to regenerate after injury. They set out to test this theory in the opossum.
They observed that opossum hearts continued to grow for several weeks after birth. They found that the hearts of two-week-old opossums resembled those of one-day-old mice, and that opossum heart-muscle cells continued to divide for weeks after birth. Experimentally induced heart damage at this age repaired itself within a month, indicating that as long as heart cells continue to divide, the heart can be repaired. These results confirmed their hypothesis, and as Kimura notes, “cardiac regeneration for more than two weeks after birth in the opossum is the longest duration observed among mammals investigated to date.”
The next step was to figure out how this is possible in opossums but not mice. Gene-expression comparisons showed that two-week-old opossums were similar to mice that were only a few days old. The researchers next looked for changes in gene expression that occurred in both animals around the time that heart regeneration was no longer possible. The common factor was a protein called AMPK. Further experiments showed that activation of AMPK in both mice and opossums coincided with the stoppage of cell division in heart muscle. Therefore, the next hypothesis was that inhibiting AMPK or its ability to work could extend the period during which heart regeneration is possible. As Kimura explains, “if we could exploit the molecular pathway that determines the capacity for cardiac regeneration, we should be able to establish novel therapeutic approaches for treating cardiovascular disease.”
They tested this hypothesis in both opossums and mice, and were successful in both cases. In particular, injecting neo-natal mice with AMPK inhibitors allowed hearts that were experimentally damaged a week after birth to regenerate and regain normal function, with minimal scarring. Thus, the researchers were able to use what they learned from marsupials and induce heart regeneration in a regular mammal.
Next on the research agenda is figuring out what triggers AMPK expression at birth in mice but not in opossums. “One important and exciting question is how neonatal marsupials retain regenerative capacity in extrauterine environments, ” says Kimura. “The answers could lead to therapies that can induce heart regeneration in adults.”
