Study details how aerobic exercise reverses degenerative process that leads to metabolic diseases
Experiments with mice and humans showed that exercise training increased the expression in adipose tissue of a key enzyme for the organism’s metabolic health, combating the harmful effects of aging and obesity
Adipose tissue is not just a simple reservoir of energy for periods of food scarcity. It contributes significantly to regulation of the metabolism, releasing various molecules into the bloodstream, including microRNAs that modulate the expression of key genes in different parts of the organism, including the liver, pancreas, and muscles.
Research has shown that both aging and obesity can impair the production of these regulatory microRNAs by adipose tissue and favor the development of diseases such as diabetes and dyslipidemia. The good news is that this degenerative process can be reversed by practicing regular aerobic exercise, according to a study published in Proceedings of the National Academy of Sciences (PNAS).
“Experiments with mice and humans have shown that aerobic exercise stimulates expression of an enzyme called DICER, which is essential to the processing of these microRNAs. We, therefore, observed an increase in production of these regulatory molecules by adipose cells, with several benefits for the metabolism,” said Marcelo Mori, a professor at the University of Campinas’s Institute of Biology (IB-UNICAMP) in the state of São Paulo, Brazil, and one of the principal investigators for the project, which was supported by FAPESP (São Paulo Research Foundation) and conducted in partnership with groups at the University of Copenhagen in Denmark and Harvard University in the United States.
The experiments were performed during the postdoctoral research of Bruna Brasil Brandão, formerly Mori’s PhD student and now at Harvard Medical School working as a research fellow in the laboratory of Professor C. Ronald Kahn.
The results showed the occurrence of communication between muscle and adipose tissue during aerobic exercise via signaling molecules secreted into the bloodstream. This exchange of information makes energy consumption by adipose cells more efficient, enabling the metabolism to adapt to exercise and enhancing the performance of the muscles.
The mice were subjected to a 60-minute treadmill running protocol for eight weeks. As they became fitter, treadmill speed and inclination were increased. At the end, in addition to the improvement in performance, the scientists found a significant elevation in adipocyte levels of DICER expression, which was accompanied by a reduction in body weight and visceral fat.
When they repeated the experiment with mice that were genetically modified not to express DICER in adipose cells, the researchers found that the beneficial effects of aerobic exercise were far smaller. “The animals didn’t lose weight or visceral fat, and their overall fitness didn’t improve,” Mori said. “We also observed that adipose cells used the energy substrate differently in these GM mice than in wild mice, leaving less glucose available for muscles.”
In humans, six weeks of high-intensity interval training (HIIT) were sufficient to yield a fivefold increase in the amount of DICER in adipose tissue on average. The effect was observed in both younger volunteers, aged about 36, and older subjects, aged about 63. The response varied considerably between individuals, however, with DICER increasing as much as 25 times in some, and very little in others.
The role of DICER and microRNA processing in adipose tissue was first described in 2012 in an article published in Cell Metabolism, reporting a study led by Mori and Khan in collaboration with an international group of researchers. The main finding here was that expression of DICER in the adipose tissue of mice declined as the animals gained weight and that this reduced their lifespan. The study also showed that caloric restriction could reverse the deleterious effects of obesity.
In another study, published in 2016 in the journal Aging, Mori and his group showed that caloric restriction in mice prevented the aging-related decline in microRNA production by adipose tissue and the development of type 2 diabetes. In a study reported in 2017 in Nature, they proved that the microRNAs produced by adipose tissue entered the bloodstream and acted on distant tissues, regulating gene expression.
“In this latest study we found that aerobic exercise, like caloric restriction, can reverse the drop in DICER expression and microRNA production thanks to the activation of a very important metabolic sensor, the enzyme AMPK [adenosine monophosphate-activated protein kinase],” Mori said.
The sensor is activated, he explained, when the cell consumes ATP (adenosine triphosphate, the molecule that acts as an energy substrate for cells) and creates an energy deficit. In experiments with mice, the researchers found that aerobic exercise activated AMPK in muscle cells and that this somehow induced DICER expression in adipose cells.
“The obvious conclusion is that the effect on gene expression occurs in the same cell in which the energy deficit occurs, which is indeed the case, but here the sensor is also activated in muscles and controls the response that occurs in adipose tissue,” he said.
To confirm communication between tissues, the scientists collected blood serum from a trained animal and injected it into a sedentary animal. This “treatment” increased DICER expression in adipose tissue. In another experiment, they incubated cultured adipocytes with serum from trained mice and observed the same effect.
“This finding suggests trained individuals have one or more molecules in their bloodstream that directly induce a metabolic improvement in adipose tissue,” Mori said. “If we can identify these molecules, we can investigate whether they also induce other benefits of aerobic exercise, such as cardioprotection. Moreover, we may think about converting this knowledge into a drug at some stage.”
To obtain an even more detailed understanding of the metabolic regulation mechanism, the researchers analyzed all of the thousands of microRNAs expressed in the organism of the trained mice and compared them with those found in sedentary mice.
“We identified a molecule called miR-203-3p, whose expression increases with both training and caloric restriction,” Mori said. “We showed that this microRNA is responsible for promoting metabolic adjustment in adipocytes. When muscles use up all their glycogen during prolonged exercise, molecular signals are sent to adipose tissue and miR-203-3p fine-tunes the adipocyte metabolism. We found this metabolic flexibility to be essential to good health as well as performance enhancement.”
Absent this modulation, adipocyte consumption of glucose during exercise increases, leaving less energy substrate available to muscles, he added. This can lead to hypoglycemia, one of the main performance limitations for athletes.
“In GM mice that don’t express DICER in adipocytes, this conversation between adipose tissue and muscles doesn’t happen. It’s a model that mimics aging and obesity. So when DICER declines, metabolic health is poor and degenerative processes accelerate” Mori said.
The 8 best microphones to help you sound better in your next video meeting
There’s plenty of technology available to help improve the quality of our virtual calls. A top-of-the-line microphone is a great start.
In recent weeks, there’s been a surge in video conferencing as many teams operate remotely due to the coronavirus pandemic. Needless to say, it only takes a few Zoom calls to realize that a standard laptop microphone simply cannot deliver high-quality audio. While some companies have provided employees with a stipend to upgrade their home office setups, many were not as lucky.
Fortunately, there’s plenty of tech to improve the quality of these virtual conferences and an aftermarket microphone is a smart way to immediately give your audio a healthy boost. Ranging from high-end broadcast-style microphones to lightning port audio accessories for recordings on the go, there’s certainly no shortage of models to choose from. Without further ado, here are some of the best microphones for the home studio.
When it comes to top-notch microphones, Blue is one of the heavyweights in the market. The Blue Yeti USB microphone is one of the manufacturer’s more versatile devices. This model comes with four different pattern modes from optimal sound quality in a host of situations. For example, those who are recording music or simply tuning in for a conference call may prefer the cardioid mode to capture the audio produced immediately in front of the unit. To more aptly record conversations between two people in the same room, the bi-directional mode captures audio from the front- and back-side of the microphone. Anyone in the market for a high-end microphone for the home studio should give this well-rounded, multipurpose mic a long look.
The Elgato Wave:3 is a versatile microphone for remote workers, gamers, and musicians alike. The microphone has a steel external grill that protects the internal components and uses a cardioid polar pattern to capture audio. The back of the device features a USB Type-C port and a headphone output. The front-facing dial adjusts headphone volume, input, and more. The stand features a u-mount for easy adjustments, and the padded base keeps the unit firmly in place. A mute feature allows you to cut the audio as needed, and Elgato offers a pop filter (sold separately) to further minimize audio disturbances.
The HyperX SoloCast USB microphone is a great option for frequent Zoom conference attendees; especially those who enjoy gaming and streaming after the workday. To prevent audio mishaps, the model features a dedicated mute button as well as an LED indicator to ensure the mic is muted or unmuted as intended. For added functionality, the model is also compatible with PS4 and popular streaming platforms.
With a steel body, matte chrome finish, and zinc die-cast elements, the HEiL Sound PR-40 certainly looks the part of a first-rate microphone. Also, the internal technology backs up the image. The cardioid pickup pattern is ideal for broadcast-style audio capturing sound directly in front and to the immediate sides of the microphone. A built-in Sorbothane shock mount reduces the risk of interference and this design includes a pair of mesh screens to improve sound quality. For additional peace of mind, this particular model comes with a limited three-year warranty.
While a more rudimentary microphone with minimal audio accouterments might fly for some, others might want to go all-in on a full home studio microphone setup. This FIFINE model includes a quality mic as well as many standard accessories for under $100. The home studio kit comes with an adjustable scissor arm for added versatility and precision placement. The included double pop filter is designed to reduce airflow immediately toward the instrument minimizing audio “pops” during recording. The package also comes with a microphone tripod stand for those so inclined.
The Shure MV5 is a solid compact microphone packaged in a vintage master of the airwaves build. Three separate preset modes (instrument, flat, and vocals) provide optimal sound quality based on the task at hand. The microphone itself easily detaches from the aluminum mount for a more low-profile tabletop fit. As is the case with other MOTIV products, this microphone also comes with the ShurePlus MOTIV app enabling users to more precisely fine-tune their recording quality and share these files.
Not everyone in the market for a high-quality USB microphone is looking for a personal home studio. This JUNIVO model acts as an excellent no-frills microphone with plenty of thoughtful design touches. The adjustable gooseneck mic body provides excellent maneuverability and the included noise-cancellation technology keeps audio crisp and clear. A central LED-equipped mute button along the base allows you to quickly cut the mic without searching from the digital button in the Zoom room. This is the perfect feature for those with pets roaming the home office.
At just four inches in diameter, the model is also appreciatively compact and ideal for desktops with limited space.
There are many situations where we need to record an audio clip on our portable devices. In fact, some professions depend on leveraging a cell phone as a modern dictaphone. Unfortunately, the low-quality onboard microphones on these devices can make transcription difficult and render live musical performances painfully inaudible. The MV88 is an exceptional microphone option for devices with Lightning ports and an adjustable joint along the mount allows users to focus the microphone closer to the sheets of sound. The aforementioned ShurePlus MOTIVE Audio apps grants users greater control over these audio files including trimming, sharing, and fine-tuning clips.
Studying Chaos with One of the World’s Fastest Cameras
There are things in life that can be predicted reasonably well. The tides rise and fall. The moon waxes and wanes. A billiard ball bounces around a table according to orderly geometry.
And then there are things that defy easy prediction: The hurricane that changes direction without warning. The splashing of water in a fountain. The graceful disorder of branches growing from a tree.
These phenomena and others like them can be described as chaotic systems, and are notable for exhibiting behaviour that is predictable at first but grows increasingly random with time.
Because of the large role that chaotic systems play in the world around us, scientists and mathematicians have long sought to better understand them. Now, Caltech’s Lihong Wang, the Bren Professor in the Andrew and Peggy Cherng Department of Medical Engineering, has developed a new tool that might help in this quest.
In the latest issue of Science Advances, Wang describes how he has used an ultrafast camera of his own design that recorded video at one billion frames per second to observe the movement of laser light in a chamber specially designed to induce chaotic reflections.
“Some cavities are non-chaotic, so the path the light takes is predictable,” Wang says. But in the current work, he and his colleagues have used that ultrafast camera as a tool to study a chaotic cavity, “in which the light takes a different path every time we repeat the experiment.”
The camera makes use of a technology called compressed ultrafast photography (CUP), which Wang has demonstrated in other research to be capable of speeds as fast as 70 trillion frames per second. The speed at which a CUP camera takes video makes it capable of seeing light—the fastest thing in the universe—as it travels.
But CUP cameras have another feature that makes them uniquely suited for studying chaotic systems. Unlike a traditional camera that shoots one frame of video at a time, a CUP camera essentially shoots all of its frames at once. This allows the camera to capture the entirety of a laser beam’s chaotic path through the chamber all in one go.
That matters because, in a chaotic system, the behaviour is different every time. If the camera only captured part of the action, the behaviour that was not recorded could never be studied, because it would never occur in exactly the same way again. It would be like trying to photograph a bird, but with a camera that can only capture one body part at a time; furthermore, every time the bird landed near you, it would be a different species. Although you could try to assemble all your photos into one composite bird image, that cobbled-together bird would have the beak of a crow, the neck of a stork, the wings of a duck, the tail of a hawk, and the legs of a chicken. Not exactly useful.
Wang says that the ability of his CUP camera to capture the chaotic movement of light may breathe new life into the study of optical chaos, which has applications in physics, communications, and cryptography.
“It was a really hot field some time ago, but it’s died down, maybe because we didn’t have the tools we needed,” he says. “The experimentalists lost interest because they couldn’t do the experiments, and the theoreticians lost interest because they couldn’t validate their theories experimentally. This was a fun demonstration to show people in that field that they finally have an experimental tool.”
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