A recent study published in the journal Scientific Reports, by Nature, reveals a technique applied with mathematical modeling that could detect the presence of neurodegenerative diseases, such as Alzheimer’s, before their most characteristic symptoms appear.

Both Alzheimer’s, as well as other neurodegenerative diseases, are very difficult to diagnose early. However, a group of Chilean researchers conducted a study that could provide an innovative way to investigate this disease through the eyes. Especially, through the electrical signals generated in the retina before different visual stimuli.

The article was recently published in the journal Nature’s Scientific Reports. There, this group of health professionals and engineers, made up of Joaquín Araya-Arriagada; Sebastian Garay; Cristobal Rojas; Claudia Duran-Aniotz, Adrian Palacios; Max Chacón and Leonel Medina, managed to demonstrate through mathematical modeling a relationship between the function of electrical activity and the early presence of this type of dementia that affects about 35 million people on the planet, according to the World Health Organization. Health.

“What we do in this study is to mathematically model a concept that exists in physiology, called “complexity”. The idea is that the complexity of a brain decreases, either with age or with disease. And, on the contrary, as long as it works well, high rates of complexity will be shown”, says Cristóbal Rojas, one of the researchers of this study and professor at the Institute of Mathematical and Computational Engineering of the Pontifical Catholic University of Chile (IMC).

According to Rojas, who is also a doctor in Mathematics and Computer Science, “complexity” is difficult to capture or measure mathematically. However, there are some signs or traces left by this complexity that can be measured. “What we do is use or adapt a tool, based on the notion of entropy, which does not precisely measure this complexity, but rather measures the level of disorder in general. There are multiple parts that come together at different scales to determine this complex behavior,” he explains.

In this context, in this particular work it was possible to measure these parameters for two groups of rats: one genetically modified to develop the disease, and the other half healthy. Both groups were shown different visual stimuli, such as lights at different intensities and a first-person video walking through a forest, in order to measure the electrical activity in the retina. “That electrical activity, over time, draws a pattern that we apply an entropy measurement to that allows us to estimate the complexity levels,” Rojas details.

This complexity, in itself, is the way in which the electrical communication between neurons is organized. Then, and as detailed by the academic, when making this visual stimulus the neuron reacts and works in a certain way, they connect and emit electrical signals with each other.

Alzheimer’s through the eyes
“What we observed is that mice, both older and those with Alzheimer’s disease, show a lower degree of complexity than young, healthy mice. So, at least we were able to find evidence that this tool could be used to distinguish these two groups and make an early diagnosis”, describes the researcher of this study. This, according to Rojas, is evidence of a potential method to diagnose the presence of this type of dementia early, before its most characteristic symptoms appear.

Cristóbal Rojas, one of the researchers of this study and professor at the Institute of Mathematical and Computational Engineering of the Catholic University (IMC).
Alzheimer’s, which accounts for nearly 70% of all types of dementia, develops and worsens over time, with symptoms appearing several years after neurodegeneration began to occur. “This study detects the decrease in complexity that would appear early. A little after the retina begins to have the presence of the ‘Tau protein’, which manifests itself when Alzheimer’s begins to develop. It is not a prediction of the disease, but rather it is a much earlier diagnosis than can be analyzed through the symptoms”, adds the researcher from the Catholic University.

There are still many studies to be carried out to apply this type of procedure in humans, explains Cristóbal Rojas. To have a good projection in this research, humans would have to be in front of these visual stimuli for a certain time, in order to have a pattern of electrical activity in the retina of people. “In this way, the ranges considered as “normal” or sick, at a certain age, could be established. But for that, it is necessary to understand well the evolution of the pattern of complexity over time”, concludes the Chilean scientist.

Scientists from the Moscow State Psychological and Pedagogical University (MSUPE) studied the impact of quarantine on the biopsychological age of the disabled.

It was established that the majority of those who went to work after confinement feel subjectively younger than a year ago, but the biological rhythm of aging increased. The results of the research were published in the journal Modern Foreign Psychology.

MSUPE scientists have long studied the biopsychological age of adults:
the general characteristic of the state of an individual,
your somatic and psychological health,
the correspondence of personal and physiological characteristics to age norms.

The concept of biopsychological age can be described with the use of two scales: biological age and psychological age.
According to experts, the first study was conducted in 2019; the second in 2020 (after about six months of quarantine). The factors that cause stress were established: the illness itself, post-traumatic stress and the factors of quarantine (social isolation, changes in diet, a reduction in physical activity and anxiety). The research included workers over 35 years of age, retirees who work and who do not work with chronic diseases.

To analyze psychological age, the scientists used the “method of independent determination of psychological age”: the participants in the trial determined their age using a 100-point scale; and the “relative psychological aging index” to compare the psychological and actual age of the trial participants. Negative figures show that an individual feels that his age is younger than the real one.
“The research highlighted that, after about six months of the quarantine, the majority of the respondents who work subjectively felt that they are younger than in reality and younger than a year ago, before the quarantine,” says the professor Head of the Department of Scientific Foundations of Extreme Psychology of the Faculty of Extreme Psychology of the MSUPE, Tatiana Beriózina.
According to her, women began to feel younger by an average of 3.3 years (adults) and 7.2 years (retired), and men, by 6.8 years (adults) and 4.7 years ( retired).

The indicator of relative biological aging (the comparison of biological age and proper biological age) made it possible to assess the extent to which an individual is older than he should be, according to established norms. To measure biological age, the researchers used the indicators of various body systems: blood pressure, stopping of breathing, after inspiration, maintenance of static balance in the left foot with eyes closed, weight, subjective assessment of The diseases.
“It is curious that the biological age of retirees with chronic diseases has not changed, while the biological age of people who work increased more than a year, as would happen in the normal aging process”, highlights Tatiana Beriózina.

According to the scientists, the impact of confinement on the somatic health indicators of individuals was diverse. The weight of women did not change during the quarantine. The assessment of their health status by men and women of all groups remained at the same level as well. Several health indicators even improved during the quarantine: pulse pressure indicators were normalized in adult women who work and retired women with chronic diseases; systolic blood pressure normalized in men.
“Quarantine had a strong negative impact on people’s physical development. They reduced their physical activity or stopped exercising and, in general, began to move less, so the characteristics of the body’s physical preparation worsened drastically. In all of them the groups decreased the time of maintaining static equilibrium, the ability of an individual to stand on one foot with their eyes closed, “says Beriózina.

Researchers noted that balance maintenance time for adult women was reduced by 26% and for retired women with chronic illnesses, by 13%. These indicators were also reduced in the groups of men: 37% in the group of adults who work and the respective trend was noted in the group of retired people who work. In addition, in the group of men, the time to stop breathing after inspiration was reduced: 4% in the group of retired people who do not work with chronic diseases, and the respective trend was noted in the other groups.
The research was carried out with financial support from the Russian Scientific Foundation, project No. 19-18-00058.

“WE MUST BE ABLE … TO PUT THE BRAKES ON HUMAN AGING.”

THE IDEA THAT WE CAN EXTEND OUR LIVES far beyond a century conjures up images of humans stored in cryogenic chambers and decapitated heads preserved in jars, kept alive by humming machines – in other words, science fiction.

But if a new study published Tuesday in the journal Nature Communications is anything to go through, such a dramatically prolonged life is not a fantasy at all. The study, which combines data from blood tests and information on physical exercise to identify a new measure of “biological age.” The findings suggest that there is an aspect of human longevity that may be crucial if we are ever to reach our full potential. Contrary to intuition, it has nothing to do with illness or a lifestyle choice.

“What we’re saying here is that the strategy of reducing frailty, so reducing the burden of disease, has only an incremental ability to improve your life expectancy,” Peter Fedichev tells Inverse. Fedichev is the lead author of the study and a researcher at the Moscow Institute of Physics and Technology. He is also a co-founder of the longevity startup Gero.

According to Fedichev and his team, humanity can do better than simply treat disease. In fact, if these results are validated, our species could begin to live for decades even longer than the maximum lifespan they determined: 150 years.

HERE’S THE VIEW – The study identifies patterns of aging and morbidity to extract the maximum possible “biological age” from humans. To do this, the researchers collected blood sample analysis data from 544,398 participants and combined it with Fitbit data from a separate, smaller subset of people. They then used the data to predict the onset of various diseases and to determine patterns in how people’s “biological age” seemed to change over time.

The “biological age” is essentially the age of the cells in your body, rather than their chronological age. To increase life expectancy, it is necessary to reduce biological age compared to chronological age. Various lifestyle choices can make a difference. If you start smoking, start a new exercise regimen, or even move to a more rural area, your biological age can decrease and increase over time. It does not remain constant.

As age increases and a more dynamic factor called “DOSI” increases, our ability to recover from disturbances deteriorates. Gero PTE. LIMITED.
In the new study, the researchers found that one factor appeared to drive individual fluctuations in biological age, a value the researchers call the “dynamic quantitative indicator of the body’s state.” To understand this measure, the researchers explain it like this: As you age, your rate of recovery from different stresses – be it illness, lack of sleep, or even hard exercise – slows down. In other words, it takes longer and longer to return to its baseline level of resilience. Therefore, people’s resistance to stress is the key to determining their longevity.

“If you don’t focus on loss of resilience, any medical intervention will fail,” the researchers write in the study.

WHY IT MATTERS: If medicine advances to the point where the diseases of aging can be cured, then researchers estimate that humans can age even longer than the maximum life expectancy they determined without addressing resilience: 120-150 years . Beyond that, our resilience deteriorates beyond the point of no return. Even the healthiest people who live longer and resist the onset of chronic diseases cannot expect to live beyond this age, they say, because their ability to recover would have been completely exhausted.

Now, 120 years of life is nothing to sniff out. But the researchers argue that if we find a way to address resilience rather than just the other issues that come with age that, to use Fedichev’s word, “disintegrate” us as organisms, then we could theoretically halt the aging process.

Fedichev tells Inverse a story he heard from another longevity researcher, Nil Brazilei, about a woman who was 105 years old and had smoked her entire life.

“All the other doctors would go to see her and ask, ‘Don’t you know that smoking is bad? Didn’t the doctors tell you? ‘”, He relates. She apparently replied, “Some of them have, and they’re all dead now.”

In other words, on an individual level, lifestyle factors may not always explain why we or do not live to old age. But resilience could.

WHAT’S NEXT: Fedichev and his co-authors don’t want to settle for the incremental increases in average life expectancy that can come from improvements in health. We already know, Fedichev says, that on average, people live longer if they have a good diet, exercise regularly, can avoid illness, and have high socioeconomic status (an important factor that is often overlooked). But people who live to extraordinary ages can also carry certain genes that predispose them to longevity.

And maybe, Fedichev says, those genes affect resilience.

If we can increase resilience, then we could extend life beyond the maximum that Fedichev and his colleagues identify here.

As part of their work at Gero, Fedichev and a team led by engineer Tim Pyrkov created an application, called GeroSense, that can calculate biological age using data provided by users. They hope to use the information they collect to measure resilience and ultimately find a solution to stop aging.

Among the factors they want to take a closer look at:

Lifestyle choices
Supplements
Subsistence allowance
Genetic markers
“What are the most nutritional and medical interventions and, finally, what are the genetic makeup variables that may or may not influence resilience?” Fedichev asks. “Because that would be the Holy Grail of aging.”

This, he says, could come very soon. “We should be able to use a drug that works against the same pathway … or do clinical trials or maybe develop something that is completely new and slow down human aging,” he says.

“I think it’s very reasonable to believe that [we will find it], in five years or more, with this resilience modifier.”

Summary: We investigated the dynamic properties of body state fluctuations along individual aging trajectories in a large longitudinal database of CBC measurements from a consumer diagnostic laboratory. To simplify the analysis, we use a linear logarithmic mortality estimate from the CBC variables as a single quantitative measure of the aging process, hereinafter referred to as the dynamic organism state indicator (DOSI). We observed that the widening of the DOSI distribution of the age-dependent population could be explained by a progressive loss of physiological resilience measured by the time of DOSI autocorrelation. Extrapolation of this trend suggested that DOSI recovery time and variance would diverge simultaneously at a critical point of 120 to 150 years of age, corresponding to a complete loss of resilience. The observation was immediately confirmed by independent analysis of the correlation properties of fluctuations in intraday physical activity levels collected by wearable devices. We conclude that criticality resulting in the end of life is an intrinsic biological property of an organism that is independent of stressors and signifies a fundamental or absolute limit of human life expectancy.