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How a sleeping cancer awakens and metastasizes

Scientists at Cold Spring Harbor Laboratory (CSHL) have determined one of the ways in which cancers in remission can spring back into action. This knowledge has inspired a new treatment idea designed to prevent cancer recurrence and metastasis.

Even after successful cancer treatment, dormant, non-dividing cancer cells that previously detached from the original tumor may still exist elsewhere in the body. If awakened, these cells can proliferate and grow into metastatic tumors. A CSHL team studying metastasis to the lungs has now identified signals accompanying inflammation that can awaken dormant cancer cells.

Whether inflammation can directly cause cancer recurrence, and if so how, has not been clear. In their new research, the team demonstrates that sustained lung inflammation, including that caused by tobacco smoke exposure, can cause dormant breast and prostate cancer cells that have traveled to the lungs to awaken and begin to divide. These cells can now form a metastasis in the lungs. Metastasis accounts for the bulk of lethality from most common cancers.

Importantly, the team, led by CSHL Associate Professor Mikala Egeblad,and including researchers from the Dana Farber Cancer Institute and UC Davis, also demonstrates a way of blocking the signaling that awakened the dormant cancer cells, a concept that could prevent cancer recurrence or lessen its frequency.

Egeblad’s team showed that sustained lung inflammation, caused either by exposing mice to tobacco smoke or to a component of bacteria known as endotoxin, induced common white blood cells called neutrophils to awaken nearby dormant cancer cells in an extraordinary way.

Neutrophils, which we normally rely upon to kill invaders like bacteria and yeast, have several ways of vanquishing their prey. One is to expel their DNA into the space beyond the cell membrane. Laced with toxic enzymes, this expelled DNA forms a gauzy, net-like trap (called neutrophil extracellular traps, or NETs) that can kill a pathogen.

The new research shows that sustained lung inflammation causes the formation of NETs in the area around dormant cancer cells. Two enzymes in the NETs, called NE (neutrophil elastase) and MMP9 (matrix metalloproteinase 9), interact with a protein in tissue called laminin. In sequence, first NE then MMP9 make cuts in laminin proteins. This changes the protein’s shape, exposing a new surface, called an epitope.

This epitope, when recognized by dormant cancer cells nearby, spurs signaling that awakens the cancer cells. “The dormant cancer cells recognize that new shape of the laminin and they say, ‘we should start growing again,'” Egeblad says.

The team created an antibody to block the epitope exposed on the laminin proteins. In mice, this prevented the reawakening of dormant cancer cells nearby. Work has begun to optimize the antibody and compare it with other approaches to interfere with NETs, with the hope of eventually conducting trials in people.

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Most effective treatment approaches for uveitic macular edema

Injections of corticosteroids directly into the eye are superior to those placed adjacent to the eye for treating uveitic macular edema, one of the leading causes of blindness in the United States, a Mount Sinai-led research study has found. The results, published in the September 27, online issue of Ophthalmology, can help to improve vision in patients with the disease.

“The results of this study suggest that we should be shifting away from periocular injections and towards intravitreal injections of corticosteroids for uveitic macular edema, which should improve the management of patients with uveitis,” said Douglas A. Jabs, MD, MBA, Director of the Eye and Vision Research Institute at the New York Eye and Ear Infirmary of Mount Sinai; Professor of Ophthalmology and Medicine at the Icahn School of Medicine at Mount Sinai; and the study chair.

Macular edema is the swelling of the macula (the area in the center of the retina responsible for good central vision) due to leakage from inflamed blood vessels; it can lead to decreased vision. It is also the leading cause of visual impairment in patients with uveitis, but can be reversed if it responds to treatment. Uveitis is a collection of more than 30 diseases characterized by inflammation inside the eye which damages the ocular tissues. It is the fifth leading cause of blindness in the United States, affecting all ages, and requires appropriate treatment to prevent vision loss. Uveitic macular edema is not always effectively treated with oral corticosteroids even when they control the inflammation, so the macular edema often requires additional therapy in the form of regional corticosteroid injections, either by a periocular (adjacent to the eye) or intravitreal (inside the eye) route.

Dr. Jabs chaired an international team of researchers as they compared and examined the effectiveness of three treatment corticosteroid approaches for patients with uveitic macular edema: regional therapy with periocular triamcinolone injections, intravitreal triamcinolone injections, and intravitreal dexamethasone implants (these slowly release mediation over a period of several months). The trial, known as PeriOcular versus INTravitreal corticosteroids for uveitic macular edema (POINT), was conducted at 23 centers across the United States, along with sites in Canada, Australia, and the United Kingdom. It followed patients for six months after the initial injection for uveitic macular edema to evaluate the injections’ comparative efficacy and safety. Patients in the trial were randomly assigned to receive either an injection of periocular triamcinolone or intravitreal triamcinolone, or the intravitreal dexamethasone implant. Researchers found both intravitreal treatments were superior to the periocular treatment for reducing macular edema and improving visual acuity. The intravitreal injection and dexamethasone implant were shown to have similar efficacy and safety profiles.

“Although all three treatments were effective in reducing macular edema and improving visual acuity, our data shows superior efficacy for intravitreal triamcinolone and intravitreal dexamethasone which suggests that the initial regional therapy of uveitic macular edema should be through the intravitreal route,” explained Dr. Jabs.

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Physical exercise improves the elimination of toxic proteins from muscles

A study published in Scientific Reports by researchers at the University of São Paulo (USP) in Brazil, in partnership with colleagues in the United States and Norway, shows that the lack of muscle stimulus results in a buildup of inadequately processed proteins in muscle cells and consequently leads to muscle weakness or wasting.

This is a typical muscle dysfunction condition that affects the elderly or individuals suffering from sciatic nerve injury, something usually verified in bedridden patients or workers who spend long hours sitting.

From tests with rats with induced sciatic nerve injury — which, therefore, stopped receiving stimuli — researchers found that this buildup was caused by the impairment of autophagy, the cellular machinery responsible for identifying and removing damaged proteins and toxins. The analysis of a group of rats subjected to a regime of aerobic exercise training previous to the injury allowed the scientists to demonstrate that physical exercise can keep the autophagic system primed and facilitate its activity when necessary, as in the case of muscle dysfunction due to the lack of stimulus.

“Daily exercise sensitizes the autophagic system, facilitating the elimination of proteins and organelles that aren’t functional in the muscles. Removal of these dysfunctional components is very important; when they accumulate, they become toxic and contribute to muscle cell impairment and death,” said Julio Cesar Batista Ferreira, a professor in the university’s Biomedical Science Institute (ICB-USP) and principal investigator for the study.

Ferreira offered an analogy to help explain muscle cell autophagy. “Imagine the muscles working in a similar manner to a refrigerator, which needs electricity to run. If this signal ceases because you pull the plug on the fridge or block the neurons that innervate the muscles, before long, you find that the food in the fridge and the proteins in the muscles will start to spoil at different speeds according to their composition,” told the researcher, who was supported by the São Paulo Research Foundation — FAPESP.

“At this point, an early warning mechanism, present in cells but not yet in fridges, activates the autophagic system, which identifies, isolates and ‘incinerates’ the defective material, preventing propagation of the damage. However, if the muscle does not receive the right electric signal for long periods, the early warning mechanism stops working properly, and this contributes to cell collapse.”

Spoiled food in a broken fridge corresponds to proteins that instead of performing their proper function form toxic aggregates, which start killing cells. Autophagy can isolate these proteins and destroy them in lysosomes, intracellular organelles that degrade and recycle waste.

“Without autophagy, a cascade effect occurs, leading to cell death,” said Juliane Cruz Campos. Campos developed part of the study described in Scientific Reports during her PhD research. First author of the article, she is currently engaged in postdoctoral research under Ferreira’s supervision with a scholarship from FAPESP.

Experiment — method

In the latest study, rats were submitted to sciatic nerve ligation surgery, creating an effect equivalent to that of sciatic nerve compression in humans. The pain it causes prevents the individual from using the affected leg, and eventually the muscles concerned weaken and atrophy.

Before the surgical procedure, the rats were divided into two groups. One remained sedentary, and the other was given exercise training that consisted of running at 60% of maximum aerobic capacity for an hour a day, five days a week.

After four weeks of exercise training, the surgery was performed, and the muscular dysfunction induced by sciatic nerve injury was found to be less aggressive in the aerobic exercise group than in the sedentary group. Functional and biochemical parameters in the affected muscles were also evaluated at that time.

“The exercise training increased autophagic flux and hence reduced dysfunctional protein levels in the muscles of the animals. At the same time, the exercise improved the muscle tissue’s contractility properties,” said the FAPESP scholarship holder.

“Exercise is a transient stress that leaves a memory in the organism, in this case via the autophagic system,” Ferreira explained. “When the organism is subjected to other kinds of stress, it’s better prepared to respond and combat the effects.”

Proof of concept

The researchers performed two other experiments designed to investigate the link between exercise and autophagy more deeply. One experiment used mice in which the autophagy-related gene ATG7 was silenced in the skeletal muscle.

ATG7 encodes a protein responsible for synthesizing a vesicle called the autophagosome that forms around dysfunctional organelles and transports them to the lysosome, where they are broken down and digested.

This experiment validated the importance of autophagy in muscle biology because ATG7 knockout mice that had not been subjected to sciatic nerve ligation nevertheless displayed muscular dysfunction.

In the other experiment, muscles from rats with sciatic nerve injury and control rats (without the injury) were treated with a drug called chloroquine, which inhibits autophagy by raising the lysosomal pH (alkalinity) and hence prevents the degradation of defective proteins.

“The tests showed less muscle strength in the control animals treated with the drug than in the untreated group. Chloroquine had no effect on the muscles of rats with sciatic nerve injury, proving that the inhibition of autophagy is critical to muscular dysfunction caused by the lack of stimulus,” Ferreira said.

The researchers stress that their studies do not aim to find a treatment for sciatica, one of the most common types of pain. The idea is to use the experimental model in further research to understand the cellular processes involved in muscle dysfunction. This will facilitate the development of new drugs and nonpharmacological interventions capable of minimizing or reversing an increasingly serious problem in contemporary societies, namely, muscle weakness and atrophy due to a lack of movement, especially among the elderly.

“If we can identify a molecule that selectively keeps the autophagic system on alert, in a similar manner to what happens during physical exercise, we may be able to develop a drug that can be given to people with muscle dysfunction due to a lack of stimulus, such as patients with immobilized limbs, people who are bedridden for long periods, and even patients with [degenerative] muscular diseases,” Ferreira said.

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Research teams find widespread inflammation in the brains of fibromyalgia patients

A study by Massachusetts General Hospital (MGH) researchers — collaborating with a team at the Karolinska Institutet in Sweden — has documented for the first time widespread inflammation in the brains of patients with the poorly understood condition called fibromyalgia. Their report has been published online in the journal Brain, Behavior and Immunity.

“We don’t have good treatment options for fibromyalgia, so identifying a potential treatment target could lead to the development of innovative, more effective therapies,” says Marco Loggia, PhD, of the MGH-based Martinos Center for Biomedical Imaging, co-senior author of the report. “And finding objective neurochemical changes in the brains of patients with fibromyalgia should help reduce the persistent stigma that many patients face, often being told their symptoms are imaginary and there’s nothing really wrong with them.”

Characterized by symptoms including chronic widespread pain, sleep problems, fatigue, and problems with thinking and memory, fibromyalgia affects around 4 million adults in the U.S., according to the Centers for Disease Control and Prevention. Previous research from the Karolinska group led by Eva Kosek, MD, PhD, co-senior author of the current study, suggested a potential role for neuroinflammation in the condition — including elevated levels of inflammatory proteins in the cerebrospinal fluid — but no previous study has directly visualized neuroinflammation in fibromyalgia patients.

A 2015 study by Loggia’s team used combined MR/PET scanning to document neuroinflammation — specifically activation of glial cells — in the brains of patients with chronic back pain. Hypothesizing that similar glial activation might be found in fibromyalgia patients as well, his team used the same PET radiopharmaceutical, which binds to the translocator protein (TSPO) that is overexpressed by activated glial cells, in their study enrolling 20 fibromyalgia patients and 14 control volunteers.

At the same time, Kosek’s team at Karolinska had enrolled a group of 11 patients and an equal number of control participants for a similar study with the TSPO-binding PET tracer. Since that radiopharmaceutical binds to two types of glial cells — microglia and astrocytes — they also imaged 11 patients, 6 who had the TSPO imaging and 5 others, and another 11 controls with a PET tracer that is thought to bind preferentially to astrocytes and not to microglia. At both centers, participants with fibromyalgia completed questionnaires to assess their symptoms. When the MGH team became aware of the similar investigation the Karolinska group had underway, the teams decided to combine their data into a single study.

The results from both centers found that glial activation in several regions of the brains of fibromyalgia patients was significantly greater than it was in control participants. Compared to the MGH team’s chronic back pain study, TSPO elevations were more widespread throughout the brain, which Loggia indicates corresponds to the more complex symptom patterns of fibromyalgia. TSPO levels in a structure called the cingulate gyrus — an area associated with emotional processing where neuroinflammation has been reported in patients with chronic fatigue syndrome — corresponded with patients reported levels of fatigue. The Karolinska team’s studies with the astrocyte-binding tracer found little difference between patients and controls, suggesting that microglia were primarily responsible for the increased neuro-inflammation in fibromyalgia patients.

“The activation of glial cells we observed in our studies releases inflammatory mediators that are thought to sensitize pain pathways and contribute to symptoms such as fatigue,” says Loggia, an assistant professor of Radiology at Harvard Medical School. “The ability to join forces with our colleagues at Karolinska was fantastic, because combining our data and seeing similar results at both sites gives confidence to the reliability of our results.”

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Postnatal depression could be linked to fewer daylight hours during late pregnancy

Women in late pregnancy during darker months of the year may have a greater risk of developing postpartum depression once their babies are born. This is consistent with what is known about the relationship between exposure to natural light and depression among adults in the general population. Deepika Goyal of San José State University in the US is the lead author of a study published in a special issue “Post-partum Health” in Springer’s Journal of Behavioral Medicine. The findings of Goyal and her colleagues should lead clinicians to encourage at-risk women to increase their exposure to natural daylight and vitamin D.

Although reduced exposure to natural light has been associated with depression among adults in the general population, there is not yet a consensus about whether light exposure or seasonality influences the development of depression during and after pregnancy.

In this study, Goyal and her colleagues at the University of California San Francisco analysed available information from 293 women who participated in one of two randomized controlled clinical trials about sleep before and after pregnancy. The participants were all first-time mothers from the US state of California. Data included the amount of daylight during the final trimester of their pregnancy, along with information about known risk factors such as a history of depression, the woman’s age, her socioeconomic status and how much she slept.

Overall, the participants had a 30 per cent risk of depression. The analysis suggested that the number of daylight hours a woman was exposed to during her final month of pregnancy and just after birth had a major influence on the likelihood that she developed depressive symptoms.

The lowest risk for depression (26 per cent) occurred among women whose final trimester coincided with seasons with longer daylight hours. Depression scores were highest (35 per cent) among women whose final trimester coincided with “short” days and the symptoms continued to be more severe following the birth of their babies in this group of women. In the northern hemisphere, this timeframe refers to the months of August to the first four days of November (late summer to early autumn).

“Among first-time mothers, the length of day in the third trimester, specifically day lengths that are shortening compared to day lengths that are short, long or lengthening, were associated with concurrent depressive symptom severity,” Goyal explains.

The findings suggest that using light treatment in the late third trimester when seasonal day length is shortening could minimize postpartum depressive symptoms in high-risk mothers during the first three months of their children’s lives. Goyal says that women with a history of mental health problems and those who are already experiencing depressive symptoms in the third trimester might further benefit from being outdoors when possible, or using devices such as light boxes that provide light therapy.

“Women should be encouraged to get frequent exposure to daylight throughout their pregnancies to enhance their vitamin D levels and to suppress the hormone melatonin,” adds Goyal, who says that clinicians should also advise their patients to get more exercise outdoors when weather and safety permit. “Daily walks during daylight hours may be more effective in improving mood than walking inside a shopping mall or using a treadmill in a gym. Likewise, early morning or late evening walks may be relaxing but would be less effective in increasing vitamin D exposure or suppressing melatonin.”

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The warm glow of kindness is real, even when there's nothing in it for you

Psychologists at the University of Sussex have confirmed that the warm glow of kindness is real, even when there’s nothing in it for you. In their study, published in NeuroImage, they undertook a major analysis of existing research showing the brain scans relating to over 1000 people making kind decisions. For the first time, they split the analysis between what happens in the brain when people act out of genuine altruism — where there’s nothing in it for them — and when they act with strategic kindness — when there is something to be gained as a consequence.

Many individual studies have hinted that generosity activates the reward network of the brain but this new study from Sussex is the first that brought these studies together, and then split the results into two types of kindness — altruistic and strategic. The Sussex scientists found that reward areas of the brain are more active — i.e. use up more oxygen — when people act with strategic kindness, when there is an opportunity for others to return the favour.

But they also found that acts of altruism, with no hope of personal benefit, activate the reward areas of the brain too, and more than that, that some brain regions (in the ‘subgenual anterior cingulate cortex’) were more active during altruistic generosity, indicating that there is something unique about being altruistic with no hope of gaining something in return.

Dr Daniel Campbell-Meiklejohn, the study’s lead and Director of the Social Decision Laboratory at the University of Sussex, said:

“This major study sparks questions about people having different motivations to give to others: clear self-interest versus the warm glow of altruism. The decision to share resources is a cornerstone of any cooperative society. We know that people can choose to be kind because they like feeling like they are a ‘good person’, but also that people can choose to be kind when they think there might be something ‘in it’ for them such as a returned favour or improved reputation. Some people might say that ‘why’ we give does not matter, as long as we do. However, what motivates us to be kind is both fascinating and important. If, for example, governments can understand why people might give when there’s nothing in it for them, then they can understand how to encourage people to volunteer, donate to charity or support others in their community.”

Jo Cutler, the PhD student who co-authored the study at the University of Sussex, added:

“The finding of different motivations for giving raises all sorts of questions, including what charities and organisations can learn about what motivates their donors. Some museums, for example, choose to operate a membership scheme with real strategic benefits for their customers, such as discounts. Others will ask for a small altruistic donation on arrival. Organisations looking for contributions should think about how they want their customers to feel. Do they want them to feel altruistic, and experience a warm glow, or do they want them to enter with a transactional mind-set?”

“Given that we know there are these two motivations which overlap in the brain, charities should be careful not to offer something which feels like a token gesture, as this might undermine a sense of altruism. Sending small gifts in return for a monthly donation could change donors’ perceptions of their motivation from altruistic to transactional. In doing so, charities might also inadvertently replace the warm glow feeling with a sense of having had a bad deal.”

“The same issues could also apply when we think about interactions between family, friends, colleagues or strangers on a one-to-one basis. For example, if after a long day helping a friend move house, they hand you a fiver, you could end up feeling undervalued and less likely to help again. A hug and kind words however might spark a warm glow and make you feel appreciated. We found some brain regions were more active during altruistic, compared to strategic, generosity so it seems there is something special about situations where our only motivation to give to others is to feel good about being kind.”

Jo Cutler and Dr Campbell-Meiklejohn analysed 36 existing studies relating to 1150 participants whose brains were scanned with fMRI scans over a ten-year period.

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Combination antibody therapy results in long-term viral suppression in HIV infection

A new generation of broadly neutralising antibodies provides a novel approach to treating HIV infection. The research group of Prof Florian Klein, Director of the Institute of Virology at the University Hospital Cologne and scientist at the German Center for Infection Research (DZIF), has collaborated with scientists at the Rockefeller University in New York and the University Hospital Cologne to investigate the impact of combining such antibodies in HIV-infected patients. Two articles on the results of this clinical trial have now been published in Nature and Nature Medicine.

Antiretroviral drugs are the critical component for effective management of HIV infection. Because of the rapid development of viral resistance against single agents, these drugs need to be administered in combination. While the currently approved drugs are highly active inhibitors of viral replication, they require daily and life-long dosing.

Compared to antiretroviral drugs, broadly neutralising antibodies have longer half-lives and can directly target the virus. In previous clinical trials conducted with participation of the University Hospital Cologne, two of these antibodies, called 3BNC117 and 10-1074, were administered individually. Both antibodies were well tolerated and resulted in significant reductions of the viral load. However, similar to treatment with classical antiretroviral drugs, the administration of a single antibody had only transient effects on the viral load and was associated with the development of viral resistance.

In the current study, the scientists investigated the administration of the combination of the antibodies 3BNC117 and 10-1074 in a total of 30 HIV-infected individuals. Antibody infusions, administered up to three times per individual, were well tolerated by all study participants. In the group of HIV-infected participants who were not taking antiretroviral drugs at the start of the trial, the antibody combination resulted in substantial reductions of the viral load.

In a second group, the antibody combination was administered to individuals who paused their previous treatment with regular antiretroviral drugs. While this interruption usually results in a rapid return of HIV to the blood, no viremia was detectable in many study participants for several months after the last infusion of the antibody combination.

“The results of this clinical trial highlight the potential for antibody combinations to maintain long-term control of HIV,” says Dr Henning Grüll, co-first author of both publications and resident physician at the Institute of Virology of the University Hospital Cologne. Based on the results of the current study that was conducted in collaboration with the Rockefeller University (Prof Michel Nussenzweig; Prof Marina Caskey), novel approaches for antibody-mediated therapy of HIV infection are under consideration that could allow for long-term control of the virus without the need for daily medication.

“The success of these studies at the University Hospital Cologne is also a result of the close collaboration with the Infectious Diseases Research Group (led by Prof Gerd Fätkenheuer) and the Infectious Diseases Outpatient Clinic (led by Dr Clara Lehmann). We are delighted that we were again able to safely and rapidly translate findings from basic research into clinical application,” says Florian Klein, principal investigator of the study in Germany.

Further clinical trials investigating additional approaches to using broadly neutralising antibodies in HIV infection are currently being conducted at the DZIF site in Cologne.

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Method to determine oxidative age could show how aging affects nanomaterial's properties

Iron oxide nanoparticles are used in sentinel node detection, iron replacement therapy and other biomedical applications. New work looks to understand how these materials age, and how aging may change their functional or safety profiles.

For the first time, by combining lab-based Mössbauer spectroscopy with “center of gravity” analysis, researchers can quantify the diffusive oxidation of magnetite into maghemite, and track the process. In Applied Physics Letters, by AIP Publishing, the work is poised to help understand the aging mechanisms in nanomaterials, and how these effects change the way they interact with the human body.

“It’s almost an unasked question about how this material oxidizes over time,” said Dr. Quentin Pankhurst. “We need more information about it. This technique helps us know what’s happening as products are sitting on the shelf.”

Distinguishing the two forms of iron oxide nanoparticles is so difficult that it has led to an unofficial convention of naming samples “magnetite/maghemite” when their composition isn’t known. Mössbauer spectroscopy uses nuclear gamma rays to measure how much of a sample has iron atoms with the +2 charge found in magnetite compared to the +3 charge that predominates in maghemite. These subtle measurements are processed with center of gravity calculations, which combines the data to create a bigger picture for the sample.

Moreover, the test doesn’t destroy samples, so researchers can track the oxidation of iron oxide nanoparticle over long periods of time.

Next, the group is looking to extend its technique to a broader range of magnetite and maghemite samples and help other researchers better understand how a nanomaterial’s age correlates with its functional properties.

“We’ve raised a question about whether the oxidative aging affects the particles, but we haven’t seen if that’s the case or not,” he said. “Now there’s this idea that aging is going on, and that’s a whole other parameter we haven’t been measuring. I’d be delighted if other people explored this correlation between function and aging in their own materials.”

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Can we teach heart cells to grow up?

Scientists around the world have been trying to replace damaged heart tissue using lab-made heart-muscle cells (cardiomyocytes), either injecting them into the heart or applying patches laced with the cells. But results to date have been underwhelming.

“If you make cardiomyocytes in a dish from pluripotent stem cells, they will engraft in the heart and form muscle,” says William Pu, MD, director of Basic and Translational Cardiovascular Research at Boston Children’s Hospital. “But the muscle doesn’t work very well because the myocytes are stuck in an immature stage.”

How the cardiomyocytes that we start developing before birth become vigorously contracting adult heart muscle cells hasn’t been well understood.

“I think there are specific signaling pathways that control that process, which we haven’t been able to reproduce in a dish,” says Pu.

Selective deletions

Studying cardiomyocyte maturation in live mice has been equally challenging. Prior studies have tried genetically engineering mice with different genes “knocked out” in their heart muscle to figure out which ones are required. But complete loss of a gene often causes dysfunction of the entire heart, which itself can impair maturation. Moreover, breeding multiple strains of “knockout” mice with different genes deleted is an expensive, time-consuming procedure.

In a new study published September 21 in Nature Communications, Pu and colleagues bypassed these hurdles. Using live mice and CRISPR/Cas9 gene editing technology, they teased out a key factor involved in heart muscle maturation in a new and novel way.

The beauty of their approach is two-fold. First, it required just one mouse strain that expresses the Cas9 enzyme, coupled with a virus that directs Cas9 to delete a specific gene. To target different genes, the researchers simply made small modifications to the virus.

“We were able to test 10 potential genes of interest within 10 weeks,” says Pu.

Second, rather than delete the gene in every cell, the researchers injected the virus such that roughly 1 in every 10 heart muscle cells was affected. This “mosaic” delivery pattern allowed the unaffected heart muscle to keep functioning. The team could then study the mutated heart muscle cells separately.

Regulating heart muscle development

One factor, known as serum response factor (SRF), emerged as a key regulator of cardiomyocyte maturation. When the Srf gene was deleted in the heart muscle of newborn mice in a mosaic fashion, many aspects of maturation were disrupted.

In normal, mature myocytes, the basic contractile structures, known as sarcomeres, are highly organized. But in the mutant myocytes, the sarcomeres became disorganized. Furthermore, normal cells develop transverse tubules, important structures that help to coordinate sarcomere contraction. These too were greatly disrupted in the mutant myocytes. Finally, the mitochondria, which provide energy and are normally arrayed alongside the sarcomeres in brick-like fashion, were dramatically reduced in size and number.

In further experiments, the team showed that SRF regulates the activity of multiple other genes, including critical sarcomere genes, in immature cardiomyocytes, but not in mature cardiomyocytes. They think that SRF receives signals from the rest of the cell which cue it to execute a master organization program during maturation.

Finally, Pu and colleagues showed that sarcomeres themselves must be properly assembled for other aspects of maturation to occur. “We learned that sarcomeres are not just important for contraction, but are probably driving the maturation program,” says Pu.

Making heart cells grow up

Overall, the results would seem to suggest that if you could just find a way to boost SRF, you could get lab-made heart muscle cells to grow up. But it wasn’t that simple: When SRF was over-expressed, the cells looked the same as those without SRF at all.

And that sets up the lab’s next goal.

“Cells seem very sensitive to the level of SRF,” says Pu. “You probably can’t manipulate SRF itself. You have to understand what’s controlling it upstream.”

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New screening tool can improve the quality of life for epilepsy patients with sleep apnea

Rutgers researchers have developed a tool to help neurologists screen for obstructive sleep apnea in people with epilepsy whose seizures can be magnified by sleep disorders.

The study appears in the journal Neurology Clinical Practice.

Although detection and treatment of obstructive sleep apnea (OSA) can improve seizure control in some patients with epilepsy, providers have not regularly assessed patients for those risk factors. The researchers developed an electronic health record alert for neurologists to evaluate a patient’s need for a sleep study.

This study can determine the necessity for treatment, which can result in improved seizure control, reduction in antiepileptic medications and reduce the risk of sudden unexpected death in epilepsy.

OSA occurs when breathing is interrupted during sleep. The Epilepsy Foundation estimates that approximately 40 percent of people living with epilepsy have a higher prevalence of OSA that contributes to poor seizure control.

“Sleep disorders are common among people living with epilepsy and are under-diagnosed,” said lead author Martha A. Mulvey, a nurse practitioner at University Hospital’s department of neurosciences. “Sleep and epilepsy have a complex reciprocal relationship. Seizures can often be triggered by low oxygen levels that occur during OSA. Sleep deprivation and the interruption of sleep can therefore increase seizure frequency.”

The researchers developed an assessment for identifying OSA consisting of 12 recognized risk factors, which are embedded in the electronic health record. If a patient has at least two risk factors, they are referred for a sleep study. The risk factors include: body mass index greater than 30 kg/m2; snoring; choking or gasping in sleep; unexplained nighttime awakenings; morning headaches; dry mouth, sore throat or chest tightness upon awakening; undue nighttime urination; decreased memory and concentration; neck circumference greater than 17 inches; excessive daytime sleepiness; undersized or backward displacement of the jaw; and an assessment of the distance from the tongue base to the roof of the mouth.

“It was found that placing this mandatory alert for providers to screen for OSA in the EHR markedly increased the detection of at-risk epilepsy patients who should be referred for a sleep study,” said co-author Xue Ming, professor of neurology at Rutgers New Jersey Medical School. “Such screening can lead to early detection and treatment, which will improve the quality of life of patients with epilepsy and OSA.”

In cases that were reviewed prior to the alert being placed in the electronic health record, only 7 percent with epilepsy were referred for sleep studies. Of those who were referred, 56 percent were diagnosed with sleep apnea. Of the 405 patients who were screened for OSA after the alert was placed in the electronic health record, 33 percent had at least two risk factors and were referred for a sleep study. Of the 82 patients who completed a sleep study, 87 percent showed at least mild sleep apnea.

 

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