Tag Archives: health

Obesity: hamsters may hold the clue to beating it

Apply by 28 February for our Research Grants of up to £10,000 (over a 12 to 18-month period). This scheme supports physiologists in their first permanent academic position or returning to a permanent position after a career break, to provide support for their research or to provide seed-funding to start a new project. Gisela Helfer was a 2017 awardee of this grant, and you can read about her research below:

The global obesity crisis shows no signs of abating, and we urgently need new ways to tackle it. Consuming fewer calories and burning more energy through physical activity is a proven way to lose weight, but it’s clearly easier said than done. The problem with eating less and moving more is that people feel hungry after exercise and they have to fight the biologically programmed urge to eat. To develop effective ways to lose weight, we need a better understanding of how these biological urges work. We believe hamsters hold some clues.

Hamsters and other seasonal animals change their body and behaviour according to the time of year, such as growing a thick coat in winter or only giving birth in spring. Some seasonal animals can also adjust their appetite so that they aren’t hungry when less food is available. For example, the Siberian hamster loses almost half its body weight in time for winter, so they don’t need to eat as much to survive the winter months. Understanding the underlying physiological processes that drive this change may help us to understand our own physiology and may help us develop new treatments.

How hungry we feel is controlled by a part of the brain called the hypothalamus. The hypothalamus helps to regulate appetite and body weight, not only in seasonal animals but also in humans.

Tanycytes (meaning “long cells”) are the key cells in the hypothalamus and, amazingly, they can change size and shape depending on the season. In summer, when there is a lot of daylight and animals eat more, tanycytes are long and they reach into areas of the brain that control appetite. In winter, when days are shorter, the cells are very short and few.

These cells are important because they regulate hormones in the brain that change the seasonal physiology of animals, such as hamsters and seasonal rats.

Growth signals

We don’t fully understand how all these hormones in the hypothalamus interact to change appetite and weight loss, but our recent research has shown that growth signals could be important.

One way that growth signals are increased in the brain is through exercise. Siberian hamsters don’t hibernate; they stay active during the winter months. If hamsters have access to a running wheel, they will exercise more than usual. When they are exercising on their wheel, they gain weight and eat more. This is true especially during a time when they would normally be small and adapted for winter. Importantly, the increased body weight in exercising hamsters is not just made up of increased muscle, but also increased fat.

We know that the hamsters interpret the length of day properly in winter, or, at least, in a simulated winter day (the lights being on for a shorter duration), because they still have a white winter coat despite being overweight. We now understand that in hamsters the exercise-stimulated weight gain has to do with hormones that usually regulate growth, because when we block these hormones the weight gain can be reversed.

When people take up exercise, they sometimes gain weight, and this may be similar to what happens in hamsters when appetite is increased to make up for the increased energy being burned during exercise. This doesn’t mean that people shouldn’t exercise during the winter, because we don’t naturally lose weight like Siberian hamsters, but it does explain why, for some people, taking up exercise might make them feel hungrier and so they might need extra help to lose weight.

file-20180621-137720-1f7h1d5

We need to find ways to overcome appetite. Lucky Business/Shutterstock.com

What we have learned from studying hamsters so far has already given us plenty of ideas about which cells and systems we need to look at in humans to understand how weight regulation works. This will create new opportunities to identify possible targets for anti-obesity drugs and maybe even tell us how to avoid obesity in the first place.

By Gisela Helfer@gi_helfer and Rebecca Dumbell

(This blog was originally published on The Conversation.)

The First Mars Marathon: Part 3

Martian nutrition: How runners will fuel

Carb-loading for the Red Planet marathon might prove more difficult than simply gorging on a pre-race pasta dinner. Since they will be shivering and burning a lot more calories not only during, but before the race, runners will simply have to eat more on Mars during the pre-race period to fully saturate their muscles with glycogen.

Just getting plates of pasta to Mars will be a major issue. After years in transit, many of the nutrients in any food shipped to Mars will have been lost, and deep-space radiation will have degraded much of a food’s chemical and physical structure. Preparing and shipping food to Mars for the runners to eat requires special methods. Anyone care for high-pressure processed, microwave sterilized, freeze-dried spaghetti and meatballs…anyone?

mars7.png

Use of critical fuels such as carbohydrate and fat will drastically increase on mars due to the extreme cold

Mid-race nutrition is equally important. As stated earlier, the drastically cold temperatures will result in a higher rate of glucose use and glycogen depletion, so the runners will need to fuel more often to keep glucose stores elevated in the face of increased use of these from shivering, coupled with the metabolic demand of running. Marathoners, who rely heavily on their glycogen stores into the later miles of the race will need to ingest glucose during the race at a rate exponentially higher than the recommended 25-60 grams per hour to avoid hitting the dreaded wall around mile 20 of the Red Planet marathon. This drink will likely have to be specially formulated with a higher glucose content.

Authors of a 1998 paper in Experimental Physiology provide evidence that providing a drink containing 15% carbohydrate was able to maintain blood glucose levels better than one containing just 2% during a cycling test to exhaustion (1). For this reason, Martian aid stations will need to occur at regular intervals and provide runners with carbohydrate-rich gels, drinks, or tasty freeze-dried space snacks.

What they’ll wear

Until we evolve into actual Martians, humans won’t get away with running unprotected on the surface of Mars. For now, technology will prove vital to success as runners on this new planet. Newly minted Martian sports scientists and gear technologists will be recruited to design a top of the line marathon-specific spacesuit.

mars8.jpg

Theoretical concept of the Mars runner suit. Source: News.mit.edu

This suit will provide a sealed, pressure-controlled environment, help maintain some warmth and control body temperature, riding a fine line between protection and optimal range of motion. A protective suit is necessary: in the low atmospheric pressure environment of Mars, bodily fluids would boil. This is known as the Armstrong limit of pressure, which Mars sits well below.

Additionally, runners will develop severe impairments in blood pressure maintenance due to the reduced atmospheric pressure. This drastic reduction in blood pressure was demonstrated in a Journal of Physiology study from 2015 (2). Studying astronauts on the International Space Station, researchers noted a reduction in blood pressure of 8-10 mmHg, mainly due to central volume expansion.  The marathon gear will resemble something of a wet suit– a design which is able to solve the low-pressure problem by using super tight wrapping  (instead of gas-pressurization, it uses mechanical counter-pressure) (3). This leaves the body mobile. Wrapping the lower limbs in this counter pressure “fabric” will allow full range of motion at the ankles, knees, and hips,

The suit will require an enclosed helmet with breathing apparatus for runners to get their oxygen which is lacking in the Martian environment and dispense of the large amount of atmospheric as well as metabolically produced CO2. But don’t even think about attempting a snot-rocket.

Additionally, features of the suit crucial to completing our space-race might include an airtight hole in the mask so that runners can ingest their mid-race fluids and gel packs.

One final, and perhaps most vital feature will be the shoes. Just as elite runners have custom shoes designed to their unique gait pattern and foot size, Mars marathoners will need footwear tailored with the same precision and comfort in mind. As it turns out, the painful condition of onycholysis (separation of the finger/toe nail from the nail bed) is not just a problem among ultra-endurance athletes, but astronauts too. Ill fitting gloves combined with the intra-suit pressure can spell disaster (and pain) for anyone carrying out activities in space, and this would surely apply to the feet as well. After 26 miles of running in cramped space-boots, it can only be expected that runners might lose one or more toenails. To prevent this, it will be necessary for runners to have Mars boots fit to their particular foot size, strike, and biomechanics.

Can They Do It?

Just as Opportunity Rover completed its own Red Planet marathon, so too will humans eventually cover 26.2 miles on foot over the dusty red surface of the fourth planet from the Sun.

Will it be fast? Probably not – but let’s hope we break the current standing record of 11 years, 2 months. Evolving a new, skipping gait required for efficient running on Mars will take some time, just as did the adaptation of lower limbs and body structure of Australopithecus to that of the modern Homo erectus, a body ideally formed for endurance running. Tendons and ligaments will have to adjust to the new microgravity environment, and it will take time for muscle fibers to regain their strength and capacity. The deconditioning of the cardiovascular system (due to fewer hemoglobin molecules, reduced ability to both supply and utilize oxygen, and decline in heart and lung function) will take some time to adapt to. Along with the various environmental factors (extreme cold, hypoxia, and dangerous levels of radiation), runners will certainly have a slow marathon debut.

We will eventually design equipment and training protocols that allow us to traverse 26.2 in record times on Mars. Remember, the first marathon run by Pheidippides resulted in his keeling over in death upon arrival. Since then, we have perfected running tactics, advanced our knowledge of performance, and unlocked human physiology such that it is now possible for man to run 26.2 miles at an astonishing 4 minutes and 41 seconds per mile, something once thought impossible.

Perhaps, some day, the elusive 2-hour barrier will be broken, not on a curated and well-paced course in Italy, but near Endeavor crater, some 54.6 million kilometers away.

References:

  1. Galloway et al. The effects of substrate and fluid provision on thermoregulatory, cardiorespiratory, and metabolic responses to prolonged exercise in a cold environment in man. Experimental Physiology. 81 (1998); 419-430
  2. Norsk et al. Fluid shifts, vasodilatation, and ambulatory blood pressure reduction during long duration spaceflight. The Journal of Physiology 593.3 (2015); 573-584
  3. Shrink-wrapping spacesuits. Jennifer Chu, MIT News Office. September 18, 2014. http://news.mit.edu/2014/second-skin-spacesuits-0918

 

How do pain meds lose their effect?

By Julia Turan, Communications Manager

You know something’s not right when more Americans are dying from pain medications than illegal drugs. This opioid crisis is filling headlines, and rightly so. However, for patients with chronic pain, tolerance to opioids such as morphine, not addiction, is the real issue. Tolerance is not usually a problem for acute pain after injuries or surgery, but for chronic pain, the patients need the drug to work over a long period.

Most studies have focused on how tolerance affects individual brains cells (neurons). New research from The Journal of Physiology clarifies a piece of the puzzle of how opioid tolerance changes the communication between neurons. This brings us one small step closer to one day developing pain therapies that avoid the development of opioid tolerance.

shutterstock_34328518.jpg

Tolerance to a drug means that larger and larger amounts are required to achieve the desired effect. Patients can become tolerant regardless of whether or not they are addicted. Tolerance does not result from abusing the drug, but rather, it can occur even when the patients follow their course of treatment as required.

The research, led by Adrianne Wilson-Poe and Chris Vaughan at The University of Sydney looked at rat brain slices after giving the animals a low dose treatment of morphine that produces tolerance. To study this, the researchers used a technique that records electrical activity in an area called the midbrain that plays an important role in the pain-relieving effects of opioids. Rather than examine individual neurons they measured how neurons talk to each because this communication is how the brain works.

BrainDiagram

To understand their findings, we need to understand a bit about how our neurons talk to each other. To send a signal, molecules travel from the sender brain cell to the receiver across a gap called the synapse. The synapse has two sides, the pre-synapse and the post-synapse. The pre-synapse is part of the brain cell sending the message, and the post-synapse is part of the receiving cell.

One of the molecules sent between neurons is called GABA. Opioids normally decrease the release of GABA. After chronic treatment with opioids, the researchers found that their dampened effect was due to fewer molecules of GABA being available on the sending side. Consequently, opioids had less of an effect on GABA release from the sending side, as there were fewer molecules around. This reduced communication between neurons is likely to contribute to reduced effectiveness of opioids after chronic treatment.

Researcher in the Spotlight May 2016

SS1

Julia Attias, Msc, BSc, is a PhD Researcher at the Centre of Human and Aerospace Physiological Sciences, King’s College London.

What is your research about?

I’m a PhD student at King’s College London researching into ways that will help to protect astronauts’ bodies in space. I research with a SkinSuit that has been designed to recreate gravity in order to help protect the health of astronauts when they go in to space. The SkinSuit may maintain the integrity of many physiological systems and processes, and it is my job to attempt an understanding of this. I am particularly interested in how the loading provided by the SkinSuit interacts with human movement and exercise, with emphasis on any changes it may incur to our energy expenditure or muscle activity. It’s also important that we understand this, in the hopeful eventuality that the SkinSuit is integrated with future space missions. It has already been integrated into International Space Station missions in 2015, and we hope for many more.

How did you come to be working in this field and was this something you always wanted to do? 

I have always been interested in extreme environmental physiology; that is, how the body functions in hostile environments. When I saw there was such a thing as an MSc in Space Physiology and Health, I jumped at the chance and pursued it in 2011-2012. During this time I started researching with the SkinSuit for my summer project. I then quickly realised how much I enjoyed doing research because it was the method by which to find out information that doesn’t currently exist. The project was (and still is) in collaboration with the European Space Agency, and thankfully the findings were of interest, and more research was warranted. I applied for funding for a PhD and two years later, I was fortunate enough to get awarded with a scholarship from the EPSRC, through King’s College London to continue researching with the SkinSuit and human movement. 

Up until university level, I actually wanted to be a TV presenter! After undertaking my BSc in sport science, I realised that I wanted a profession in physiology, and after my MSc, I realised I wanted a profession in space physiology/research. 

Why is your work important?

Plans for human space exploration on a far greater scale than what has been achieved before are on the agenda globally. Visits to Mars are expected within the next 20-30 years. In order to do so effectively, maintaining human function from lift off to landing is of utmost importance. The ideal recipe of countermeasures to tackle longstanding physiological de-conditioning associated with reduced gravity environments is yet to be determined. My work will hopefully go some way towards this, and if I can help even 0.0001%, I’ll be over the moon (no pun intended). 

Do you think your work can make a difference?

I really do believe so. The beauty of the research field I am in is the applicability of the findings to many other populations. Although I research with a countermeasure primarily designed for astronauts, populations such as those that are bed rested/immobilised for long periods of time, those that suffer from disuse atrophy, and those that have suffered from sustained injuries could all benefit from any positive research findings, owing to the analogies in physiological de-conditioning between these populations.

What does a typical day involve?

 A day in the life of me changes every day! It’s one of the things I like; every day is relatively unpredictable, though has its stable duties. I check emails continuously throughout the day as I work with international collaborators and we are all on different clocks. In addition, I will be working on whatever study I currently have running. So it may entail writing the ethics application, planning the study, testing subjects in the lab, analysing the data, or writing the results up and drawing some conclusions based on reading literature. Often I will create an abstract or presentation for a scientific conference. I have regular meetings with my supervisors/colleagues and peers and I also help to teach undergraduate physiology laboratory practicals, so based on the time of the year that could take up a chunk of my day too.

What do you enjoy most in your job?

Being a scientist is hugely beneficial to us all, as breakthroughs – whether about space, cancer, nutrition, exercise, plant biology, etc. – are found primarily through scientists working to tackle the world’s problems, and it feels great to be a part of that. It’s also hard not to enjoy meeting astronauts from time to time! 

What do enjoy the least?

Sometimes it can be disheartening when you didn’t find what you expected to find with your results, or similarly when you find something you didn’t expect to. Although on the flip side, I guess that’s what makes science science, and that’s what makes us as scientists curious to find out why that may have happened. After all, some scientific theories came through unexpected findings! It’s also not the most enthralling job in the world sitting in front of thousands of rows of numbers on an excel spreadsheet ready to analyse! But it’s all part and parcel of the job, and the end result of understanding your findings is always worth it.

Tell us something about you that might surprise us…

I used to dance as a teenager, and performed twice on the BBC show Blue Peter. And of course, I have two badges to show for it!

What advice would you give to students/early career researchers?

Be curious. Don’t settle for knowing ‘that’ something happens; you need to want to know ‘why’ it happens. This curiosity will inadvertently cause you to be inquisitive, creative and determined. Don’t let the word ‘can’t’ live in your vocabulary and don’t take no for an answer if your gut tells you otherwise. I believe we can do anything we set our minds to, if we want it badly enough. Find something you feel passionate about – this will fill you with the motivation you need to work hard, be determined, and succeed.

SS4

Researcher in the Spotlight April 2016

mcnarry-melitta-img0280

Dr Melitta McNarry is a Senior Lecturer, College of Engineering at Swansea University and specialises in cardiorespiratory fitness across the health, fitness and lifespan with a particular interest in paediatric populations. 

 

 

What is your research about?

My recent work has focused on the development of non-pharmacological intervention strategies, such as inspiratory muscle training and high intensity interval training, for people with asthma and cystic fibrosis. I specialise in cardiorespiratory fitness across the health, fitness and lifespan with a particular interest in paediatric populations. Recent work has focused on the development of non-pharmacological intervention strategies, such as inspiratory muscle training and high intensity interval training, for people with asthma and cystic fibrosis.

Furthermore, I am interested in the role of pulmonary rehabilitation for patients with respiratory disease, especially Idiopathic Pulmonary Fibrosis, and the potential modifications that can be made to traditional strategies to optimise the outcome for the patients. With regards to such patient populations, I have recently begun to investigate the relationship between rheological parameters, namely blood clotting, hypoxia and exercise. Finally, following on from my PhD work, I continue to investigate the interaction between training and maturity on the bioenergetics responses of children and adolescents.

How did you come to be working in this field and was this something you always wanted to do?

While studying for my Biology degree at the University of Exeter, I realised that I was more interested in human physiology than plants or microbiology, so when a conversation at training one evening led to the offer to complete my dissertation in the School of Sport and Health Sciences I jumped at it! Little did I know this was just the start as following the success of my undergraduate dissertation I was offered a scholarship to complete a PhD at the University of Exeter. Whilst not something that I planned to do when I was “older”, I have been brought up in an academic family so it wasn’t a foreign concept when the opportunity arose.

Why is your work important?

My work unites theory with application, aiming to provide real-world solutions to pathophysiological conditions that do not revolve around pharmacological interventions. I therefore believe that my work has the potential to improve patients’ quality of life on a daily basis – even if this is only one patient I would count this as an important impact from my work.

Do you think your work can make a difference?

I think my work has the potential to make a difference on the individual patient level, improving the functional capabilities and enhancing their quality of life.

What does a typical day involve?

I would say that the joy of this job is that there is no such thing as a typical day, every day differs with the only common features being that they are generally too busy and that I never get what I planned to do that day done but a thousand other things instead! Nonetheless, a ‘typical’ day involves getting to work early in the morning to try and fight a rising tide of emails before numerous meetings with everyone from undergraduates to internationally renowned professors. This is then combined with giving lectures and running lab sessions for our undergraduates and, on the good days, with conducting testing to advance our studies and research.

What do you enjoy most in your job?

I enjoy working with children and patients in the lab and field, interacting with them and seeing research translated into real-life. The mundane (aka, admin-related) elements of the job often make you wonder why you continue working such hours but the rare moments you get to run physiological tests with participants reminds you why you started.

What do enjoy the least?

The requirement to be a jack-of-all-trades from teaching to research to administration, resulting in you being a master of none.

Tell us something about you that might surprise us…

I am not formally trained in Sport Science or Exercise Physiology! My undergraduate degree was in Biosciences.

What advice would you give to students/early career researchers?

Working hard is more important than intelligence, but sometimes things will happen at their own pace and nothing you can do will speed it up; be patient as if it is meant to be, it will be.