Friday, March 2, 2012

Exercise, Lysosomes, and Cellular Garbage Recycling


A new research article in the journal Nature sheds some light on why regular exercise is so valuable for health.  What is really interesting about this research is that it explains not only why exercise is great at preventing illness but it also helps explain how exercise can actually reverse chronic diseases like diabetes.

As you probably know, exercise is one of the essential keys to a healthy life. It is critically important for virtually every facet of health. Almost any disease or disorder you can name has at least a dozen studies that show the health benefits of regular exercise. It’s not always exactly clear why or by what mechanism exercising helps, but the resulting benefits are pretty clear. This research definitely helped me to understand what happens in my body during exercise and I hope it will help you too.

I am going to spend a little time giving you an in depth look into this new research because I think it might help motivate you to exercise. I found that once I was able to visualize what this research study demonstrated, I felt motivated to move and exercise more.

This research suggests that exercise is key to the proper and healthy functioning of lysosomes in your body. So what are lysosomes, why do they matter, and what does this new research tell us about how to get healthy?

LYSOSOMES AND CELLULAR RECYCLING

The human body is a miracle of efficiency and is very good at reusing and recycling nutrients. Your cells like to reuse materials whenever possible, and lysosomes are the part of each cell that allows cells to reuse the building blocks (e.g. proteins and fats), rather than having to make new ones from scratch.

A look inside your cells. Lysosomes are tiny, but their importance
to health is huge. (Click on the image for a larger version)
Lysosomes perform this critical recycling function by gathering up and engulfing things, and then “digesting” them (breaking them up) into their constituent parts. Lysosomes recycle misshapen proteins, other dying or dead cells, damaged mitochondria, foreign bacteria or viruses, and basically anything else that could contain useful ingredients that could be reused by your cells.

You may wonder, “if I am healthy, then my cells must be healthy, so I shouldn’t need lysosomes to recycle cells and proteins right?” Actually, you still do because nobody’s cells are perfect. From time to time, even your healthy cells make mistakes while doing their work building proteins. Furthermore, even while your cells are working normally, there are still waste products that need to be removed. The food you eat and medicines you take must all be metabolized and some waste is always generated in the process.

Much like most “garbage”, many of these waste products can be recycled or reused with some minor reprocessing by lysosomes. This is very efficient for your body because it saves your cells using up energy trying to dispose of cellular “garbage” and the recycling means that your cells need fewer raw materials to begin with.

Since lysosomes help raise the efficiency of your cells by recycling materials, it stands to reason that by helping lysosomes work harder, you might be able to increase your overall health (or cellular efficiency). This new research tackled this very question by looking at what changes exercise might have on lysosome activity.

THE RESEARCH

The method - Two sets of mice:

Researchers studied two different sets of mice to observe changes in lysosome activity. Researchers compared what happened to lysosomes in both groups of mice by making them perform exercise and changing the quality of their diets. The two groups of mice had a fundamental difference that made it easy to see changes to lysosome activity.

  • Normal mice: The researchers suspected that they would see a change in the lysosome activity of these mice when “stressed” by exercise and a poor diet. Researchers looked at the lysosomes of these mice to see if their suspicion was correct.
  • Specially modified mice: The researchers found a way to modify a second group of mice so that the activity of their lysosomes could not change. In other words, no matter what the mice did or how stressed they were, their lysosomes would remain at a constant level of base activity (sort of like an idling engine).

After stressing both groups of mice with exercise, the researchers could then compare the lysosomes of the modified mice to those of the normal mice. In addition, the mice were then fed a diet that is known to cause diabetes; the researchers again looked at what happened to both sets of mice. This comparison let the researchers see exactly what changes to diet and/or levels of exercise had on the lysosomes of “normal” mice.

Watching lysosome activity:

Watching lysosomes in action isn’t easy. They’re tucked away inside cells, they’re microscopic, and it’s hard to watch them in action. In order to “see” the lysosomes, the two groups of mice had the outer membrane of their lysosomes stained with a dye. This allowed the researchers to see the lysosomes much more easily. Once they could see the lysosomes easily, the researcher could actually watch what happened to the lysosomes of the two different types of mice when they were stressed by exercise and a poor diet. Other factors such as the endurance during exercise sessions (i.e. how long until they got tired) and glucose metabolism (i.e. how efficiently they burned energy) were also monitored in each set of mice.

THE RESULTS

  1. The cells of the modified mice did not function as well as those in the normal mice, especially during exercise.
  2. The mice with normal lysosomes performed better at exercise and were able to reverse diabetes by exercising.
  3. Exercise increases the activity of lysosomes.
WHAT DOES IT MEAN?

1) The cells of the modified mice did not function as well as the normal mice.

In the modified mice, the stress of exercise caused their cells to function poorly, compared to the “normal” group. The mice had significantly lower exercise endurance and poor metabolism of glucose. The unchanged lysosome activity and increased stress basically meant that clearing out increasing metabolic waste (from high levels of exercise or poor diet) was slower than it would normally be; this, in essence, “gummed up the works” in the cells, causing cells to perform poorly. In addition, when these modified mice were fed a poor diet (one that is used to cause diabetes in mice), they quickly developed diabetes.

2) Mice with normal lysosomes perform better and recover from disease:

However, in the unmodified (i.e. normal) mice, increasing exercise caused their lysosomes to kick into high gear. The researchers saw (because of the dye) this increased activity in the lysosomes of the normal mice. Lysosomes actually got bigger, gathering up more of the recyclable materials in the cell and breaking them down to be reused. This increase in lysosome activity, in turn, led to cells being better able to function; the mice could exercise longer and were better able to metabolize energy (in this case, glucose). Even when given a poor diet, which causes diabetes in mice, they still demonstrated better endurance than the modified mice. Interestingly, the normal mice actually reversed the symptoms of their (dietary induced) diabetes through exercise, even while they were on the same diet that initially caused their diabetes.

3) Exercise is key to increasing lysosome activity and health:

So, what this means is that exercise, through some mechanism, makes lysosomes work harder. Harder working lysosomes clear out and reuse much more of the leftover waste in cells, which means less stress on cells overall. So, increasing lysosome activity appears to be a crucial part of maintaining proper cellular metabolism. When cellular metabolism operates at a higher efficiency, chronic illnesses (in this case, diabetes) may even start to disappear. This is almost certainly not the only reason why exercise is good for health and preventing illness, but it appears to be a key part.

LYSOSOMES AND ENERGY

Exercise needs energy:

It’s probably not a surprise to you that exercising uses up quite a bit of energy. The energy you use can come from a couple of different sources, but your body uses glucose as it’s first choice for energy for your muscles and brain. “Blood sugar” (or blood glucose) levels are an important part of how well you can perform both physical and mental exercise. You’re probably familiar with the way “low blood sugar” can make you feel cranky, tired, irritable, and sluggish.

Once you burn through the glucose in your bloodstream (and glycogen in the liver), your body will switch to burning fat and using protein for energy instead. This is where lysosomes are critical because one of the first available sources for protein energy comes from lysosomes. Lysosomes break down errant or unneeded proteins and other things rounded up inside the cells as “garbage”. Once broken down into building blocks (e.g. amino acids, fatty acids, etc.), your cells can easily make other sources of energy (e.g. ketone bodies) for your muscles and brain.

Lysosomes help make energy:

Exercise appears to send a signal to the lysosomes that your body needs energy. It’s very similar in nature to the “starvation response”, where your body doesn’t have access to immediate food (or fuel), so your cells start switching from using glucose as fuel for cells to using fat and protein. This switch appears to trigger your lysosomes to work harder. It makes sense, since both exercise and periods of time without food essentially both use up the glucose available to your cells. Lysosomes help to jump start the switch to fat/protein energy use by recycling fats and protein material inside cells so that they can be used as fuel.

CONCLUSION

Lysosomes are clearly essential for our well being and exercise appears to be an important factor in boosting the activity of lysosomes inside our cells. So exercise helps our cells by stimulating lysosomes to clear away and reuse cellular debris. By boosting the activity of lysosomes, exercise actually makes cells function better overall, even producing things they need (amino acids, fatty acids, etc.) in the process.

This research sheds some light onto a key reason why exercise is so valuable for health. We’ve all heard about the myriad health benefits of exercise, and now we can see how our lysosomes play a crucial role in this process. Exercising regularly will keep your lysosomes working hard.

For another look at the value of exercise you may want to have a look at our recent post on the biggest single thing you can do to improve your health.

source: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10758.html

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Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

2 comments:

  1. Thanks for the great post! Minor quibble: they used mice, not rats

    ReplyDelete
  2. Thank you for your comment. You are absolutely correct. I updated the post to reflect that.

    ReplyDelete