Eosinophils rejuvenated mice
Weakness and decreased immunity are the two main characteristics of old age. Researchers from the University of Bern and the University Hospital of Bern have demonstrated in animal models that these two age-related disorders can be stopped and even eliminated with the help of a new cell therapy tactic.
Older people are more susceptible to infectious diseases, as the function of the immune system decreases with age. As the effectiveness of vaccination in the elderly weakens, this age group is particularly vulnerable to seasonal infectious pathogens and often has the highest mortality rate.
In addition to the age-related decrease in immunity, older people usually suffer from weakness, which negatively affects the quality of life. Despite the fact that the average life expectancy of people continues to grow, it is often associated with age-related health problems. The researchers decided to identify new strategies to improve the health of the aging population.
The role of abdominal fat in aging
Scientists have long assumed that sluggish chronic inflammation accelerates the aging process and the development of age-related disorders.
In a new study, an international team has demonstrated that visceral adipose tissue, or abdominal fat, plays a crucial role in the development of chronic inflammation. Dr. Mario Noti from the Institute of Pathology at the University of Bern and Dr. Alexander Eggel from the Department of Biomedical Research at the University of Bern reported that they have identified immune cells in the abdominal adipose tissue that regulate mild chronic inflammation and aging processes. They have shown that these immune cells, being targets for therapy, will help reverse age-related changes.
Abdominal fat as a source of chronic inflammation
The group of Noti and Eggel proved that eosinophils, which mainly circulate with the blood, are also present in the abdominal fat of both humans and mice. In addition to providing protection against parasitic infection and contributing to the development of allergic diseases of the respiratory system, eosinophils located in the abdominal cavity are responsible for maintaining local immune homeostasis.
Detection of eosinophils in human visceral adipose tissue using two different staining methods. Eosinophils are marked with arrows. AD – adipocytes; V – blood vessel. Source: University of Bern.
With increasing age, the number of eosinophils in abdominal fat decreases, and pro–inflammatory macrophages increases. Due to this imbalance of immune cells, abdominal fat turns into a source of pro-inflammatory mediators that accumulate in old age.
Eosinophilic cell therapy promotes rejuvenation
The next step, the researchers studied the possibility of reversing age-related disorders by restoring the immune cellular balance in visceral adipose tissue. Using various experiments, they were able to show that the administration of eosinophils from young mice to old recipients reduced both local and systemic inflammation of a mild degree. This effect was partially mediated by eosinophilic interleukin-4 (IL-4), a cytokine that suppresses the activity of macrophages and their secretion of pro–inflammatory factors (interleukin-1, tumor necrosis factor, interleukin-6).
The researchers observed that eosinophils from donors selectively accumulated in adipose tissue. They noted the rejuvenating effect of eosinophils on the aged organism of recipient animals. The mice showed a significant improvement in physical fitness, which was assessed using endurance and grip strength tests. In addition, the therapy had a rejuvenating effect on the immune system, manifested in an improved response to vaccination in old mice.
The introduction of eosinophils increases the number of these cells in adipose tissue and weakens age-related chronic low-grade inflammation, leading to systemic rejuvenation of the aged organism. Source: University of Bern.
Translation of results into clinical practice
The biological processes of aging and related functional disorders turned out to be more plastic than previously assumed. It is important to note that the observed senile changes in the distribution of immune cells in adipose tissue in mice have also been confirmed in humans. The goals of future research will be to use the knowledge gained to create targeted therapeutic strategies to promote and maintain healthy aging in humans.
Article by D.Brigger et al. Eosinophils regulate adipose tissue inflammation and sustain physical and immunological fitness in old age is published in the journal Nature Metabolism.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the Universität Bern: Age-related impediments reversed in animal model.