Tuberculosis, smallpox, and the flu may have looked differently and behaved differently, but they were all the result of coming into contact with tiny little organisms we couldn’t yet see. The discovery of bacteria and viruses allowed scientists to develop effective treatments for the illnesses they cause.
The awareness sweeping science today is that the same principle may be true for the diseases of ageing. Heart attacks, cancer, and diabetes all look different and behave differently, but if we can understand their common cause, we may be able not only to live longer, but also to age with more of our health intact.
WHAT’S THE DEAL WITH STEM CELLS?
One new area of medicine that’s received a lot of attention recently is regenerative medicine, which uses stem cells to help heal and repair damaged and diseased organs. There’s been a lot of excitement about the potential of stem cells to heal, as well as much controversy about how they are harvested.
There are two main classifications of naturally occurring stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells have tremendous value in medical research because they have the ability to divide and become other types of cells. Embryonic stem cells come from human embryos, which contain cells that can differentiate into one of three kinds of primary cell layers (ectoderm, endoderm, and mesoderm) that have the potential to turn into any kind of cell in the body, from skin to muscle to nerve. But the practice of harvesting embryonic stem cells is controversial.
Then there are adult stem cells, also called somatic stem cells, which live in the tissues of our organs. We now know that adults have stem cells in our brains, bone marrow, blood vessels, skin, teeth, heart, gut, liver, ovaries, and testis. These powerful cells are always at the ready to heal and repair, and have the potential to morph into other types of cells needed by the organ. Stem cells can remain dormant for a long time until they are needed to make more cells, or until a disease or injury incentivizes them to spring into action. Some adult stem cells can also be activated following exercise (as if you needed another reason to get your body moving!). The challenge of treating disease with adult stem cells is that adults have few stem cells in our tissues, and even once those have been harvested and isolated in a lab, growing more of them isn’t easy.
Enter induced pluripotent stem cells (iPSCs). The 2012 Nobel Prize was awarded for the discovery that mature cells – normal adult cells, like skin cells – can be reprogrammed to become immature, embryonic-like cells capable of developing into specialized cells. These time-machined cells can then be used for treatments throughout the body. Since this breakthrough, researchers around the globe have been creating iPSCs and encouraging them to divide to become skeletal cells, epithelial (tissue) cells, and cardiac cells to see if they can form new bones, skin, and hearts.
What’s so exciting about iPSCs is that they provide a way around the embryo-harvesting issues and ensure a scalable supply of adult stem cells for research and treatment. Not only that, but these cells can be derived from specific people, and so it will be your cells that are potentially made into the new cardiac cells you need after a heart failure, or your cells that make the dopamine cells you need to replace those lost in Parkinson’s disease.
Over the coming years, we will be hearing more about the future of regenerative medicine and transplants. Scientists are very optimistic about the therapeutic potential of stem cells.
Think about that for a moment. If ageing is the common cause of those illnesses, and we can increase our understanding of ageing at the cellular level, we may be able to live with strength and health until we die quietly in our sleep. Our bodies will weaken naturally, and ageing puts us at risk of a host of diseases, but a risk factor is not a diagnosis. It’s a call to action, to arms, and to attention. Knowing the risks can empower us to become the architects of our own strength and resilience.
HOW AGEING IS STUDIED
We are ageing in a time when science is committed to and compelled by the question “What is ageing?” The science of understanding ageing takes place in laboratories and meeting rooms, at desks and with the help of technology. Study participants may dutifully take medications, try different ways of eating, of moving, of sleeping, or just give up their privacy and answer loads of questions, all so that we can better understand how ageing affects our bodies. The test groups for these studies range in sample size from a hundred people to hundreds of thousands of people. When we see the results of the latest research plastered all over social media or mentioned in a morning news show or even announced in the headlines of newspapers, it’s important to keep in mind that every study varies in terms of how it collects its data. Data can be influenced by how many participants are included, and also by how well a study is designed and the elements for which its researchers are controlling – factors ranging from time and temperature to gender and age may affect a study’s accuracy.
One type of research method is the observational study. Observational studies assess how the choices people make affect their wellness. Some of these studies, like the Framingham heart study (see here), are longitudinal – they track participants over a sustained period of time. Longitudinal studies can last for decades, and they have been very useful in helping us understand ageing.
Observational studies can also examine a cross-section of people and compare them with one another to see how their choices have influenced their health. For example, one cross-sectional study compared older people with similar health profiles to determine the effects of vitamin D deficiency (answer: it can put you in a lousy mood as well as impair your ability to think clearly).
Some studies are less about observing, and are more about getting involved. An interventional study gathers groups of people to study for comparison. Researchers ask one group to implement a specific behaviour in order to observe its impact on health, and use the other group as a control for comparison. For instance, when researchers wanted to understand how the intensity levels of physical activity would affect memory, they organized sixty-two healthy older people into three groups. Over the course of six months, one group performed medium-intensity workouts, one group performed low-intensity workouts, and the other group did not work out at all. The study found that any exercise had great benefits for memory and brain volume, with little difference between the low- and medium-intensity groups.
When researchers study ageing, they don’t only observe humans, they also turn to human cells, animal cells, bacteria, mould, and fungi. They experiment on lab animals (and sometimes wild animals), from sponges and worms to mice and monkeys to naked mole rats. By examining and manipulating genes from other animals, scientists can gain insights into the human ageing process. Although worms look nothing like human beings on the outside, internally, like flies, they have many genes and biological mechanisms in common with us. And just like people, worms and flies age, albeit at a much faster rate. Within a year’s time, many rounds of testing and learning can take place on worms and flies, whereas watching humans age in observational studies takes a human lifetime – more time than one scientist has on her hands.
Comparative biology can also yield important insights. Naked mole rats, which are somewhat terrifying-looking mouse-sized
