BarcelonaPeople who suffer from obesity are often singled out for their supposed unwillingness to adopt healthy habits, blamed for not trying hard enough to change diets and lose weight or, in the case of having undergone a bariatric surgery, for not being constant in physical exercise. Its intrinsic complexity has meant that this disease is strongly stigmatized and that, despite the fact that it already affects almost one in five Catalan adults – one in eight people in the world –, its healthcare approach is still very deficient.
It is estimated that only 10% of those affected can receive specialized treatment, and accessing it is not a guarantee either, since many experience the so-called yo-yo effect, which makes them regain the lost weight after a while. Researchers everywhere are not only looking for therapies and innovative drugs to put a siege to this increasingly prevalent pathology – the paradigmatic example is Ozempic – but also explanations to find out what is hidden behind it. In other words, what explains the fact that there are people at greater risk of obesity or with more difficulty in controlling it. This Monday researchers from the Federal Polytechnic School of Zurich (Switzerland) have published a study a Nature in which they propose that this susceptibility would be produced by epigenetic modifications of the adipose tissue cells (adipocytes) that last over time.
“Adipose cells remember the state of being overweight and can return to it more easily”, highlights the leader of the study, expert in epigenetics Ferdinand von Meyenn. Colloquially known as fat, adipose tissue retains a kind of memory of obesity that persists after weight loss, according to the Swiss team. In other words, the key to understanding the chronicity of the disease – and the need to prevent secondary complications such as type 2 diabetes or fatty liver disease – should be found in epigenetic changes. The finding suggests that these small, characteristic chemical markers don’t alter the way DNA works – what every organ is supposed to do – but they do regulate the way genes are expressed and behave, and can therefore predispose to suffering long-term obesity.
The sequence of the basic components has evolved over time and epigenetics is inherited, but these markers are dynamic and are also conditioned by environmental factors, eating habits or the state of the organism that can modify them over time the life “Epigenetics tells a cell what type of cell it is and what it should do,” explains Laura Hinte, one of the study’s signatories. To demonstrate this rapid recovery of fat deposits, the researchers used fat cells from mice and humans. The Swiss scientists observed that in rodents that had these epigenetic markers in adipose cells by induction of obesity, they regained the lost weight more quickly when they were given access to a high-fat diet again.
How did they see it? The animals had changes in the way DNA is copied into RNA, the process that regulates gene expression. In humans, the study included 18 non-obese individuals and 20 who had undergone bariatric surgery and lost at least 25% of their body mass index (BMI). The scientists took samples from those affected both before and after the intervention and also observed changes in genes or molecular processes that they defend the body of weight loss.
Reset the memory
“The Real World Implications [d’aquest estudi] are significant. The study highlights the biological basis of weight regain, reduces stigma and emphasizes the need for long-term supportive interventions. It also opens avenues for targeted therapies, for drugs or epigenetic editing, for restart the memory of the adipose tissue and improve the maintenance of weight loss”, assesses in statements to SMC José Ordovás, director of nutrition and genomics at Tufts University in Boston (USA) and member of the Biomedical Research Center in Physiopathology of the ‘obesity and nutrition (Cyberobn) of the Carlos III Health Institute, however, notes that this research does not establish causality between epigenetic changes and weight regain and stresses that further research is needed to confirm the underlying mechanisms.
Von Meyenn emphasizes that strategies focused on diet and lifestyle changes often only result in short-term weight loss, which can be reversed over time (at least for two years) and is known to like the yo-yo effect. Instead, continues the lead researcher, if the changes in adipose cells were acted upon in the future “weight control and long-term health could be improved.” Ordovás agrees: “Personalized weight control strategies could be based on an individual’s genetic and epigenetic profile, while public health policies could prioritize prevention and early intervention to avoid the establishment of a memory obesogenic”.
