Lab animals – what can they tell us about human health?

TV news very often show us breakthrough discoveries that scientists have made in lab animals. Novel surgical procedures for organ transplantation, new drugs to prevent obesity and therapies to improve memory are commonly developed in small animals and are claimed to open new roads towards the cure for human diseases such as diabetes and Alzheimer’s. But can hopes be raised so high when discoveries are made in such small creatures? Does it really lead to new treatments in humans?

The answer is a big YES. The first reason for that is the fact that small animals and men are much more alike than it appears. For example, the human genetic material is so similar to rats’ that more than 90 % of the human genes have their counterparts in rats. Further, most organs have extremely similar shape and function in rodents and humans, making such tiny animals a really good tool to help understanding how human physiology works, and consequently serve as an important first step towards development of new drugs and non-pharmacological therapies to treat human diseases.

Rat face closeup on black backgroundSuch rationale is called the “bottom-up approach” – when research starts in small model organisms and progresses to applicable knowledge in large human populations. This idea has generated outstanding medical advances. Here comes a few examples:

  • In 1914, John Abel showed that rabbit blood could be filtered outside the body and be returned safely to the animal. This discovery was used to develop hemodialysis techniques that are used to treat patients with kidney failure.
  • Later in the 1920s, Frederick Banting realized that some substance of the blood from normal dogs was able to keep diabetic dogs alive. This substance was later identified as insulin, which is used to treat type 1 diabetes.
  • Forty years later, Albert Starr refined cardiac surgical procedures in pigs. His technique is still used nowadays in more than 300.000 human patients every year.

So, what does this have to do with CERG? Well, actually quite a lot, because we have also been using the “bottom-up” approach in order to better understand and treat cardiovascular diseases, and there are quite nice stories to count. Ten years ago, CERG research showed that high-intensity training improved heart function in rats with cardiac problems. This and other studies in animal models supported the idea of training cardiac patients in high-intensity protocols, which was condemned by physicians a few years back. The trained rats also showed tremendous enhancement of the molecular machinery inside the heart cells, which was the reason for the cardiac improvements. Then, some time later, another study by CERG showed that heart failure patients had larger improvements with high-intensity training than with moderate-intensity. And finally, last year our group observed that the cardiovascular risk of performing high-intensity training is low for cardiac patients, even when a large population is considered, concluding a successful cycle of “bottom-up” research.

IMG_5683An equally nice story was also built in regard to training for treatment of metabolic syndrome, when CERG researchers showed that high-intensity training improved cardiovascular parameters in small animals and then human patients with metabolic syndrome.

Our next step in this journey is to discover the genes responsible for the “natural runners” – the people with high aerobic fitness even without any training. For that, we are joining molecular data from “natural runner” rats and genetic information from humans (the HUNT fitness study). Through this, we are aiming to unveil the differences in cardiac genes between high- and low-capacity runners. We even want to provide novel biomarkers for aerobic fitness, which could be used to predict future cardiovascular health or treat cardiac problems.

From a wider perspective, the focus in CERG is improving people’s cardiovascular health, and training is our main tool. That is why we dig so deep on understanding all the aspects of exercise, from its effects in the general population to invisible mechanisms inside the cardiac cells. The path we’re taking is long and bumpy, but the future is hopefully bright!

Jose Bianco Nascimento Moreira, PhD candidate at CERG.