Discovering Nature's Paradox: Low Pathogen Exposure Boosts Organismal Fitness

How Low Infection Levels Can Support Health: New Opinion Paper Challenges Prevailing Beliefs

A recently published opinion paper by a team of researchers led by Jena professor and Microverse board member Prof. Dr. Michael Bauer has provided initial evidence that a minor infection can strengthen the body's defense and general fitness. The authors thus argue against the prevailing view that infectious diseases are exclusively harmful. In addition to Michael Bauer, Microverse researcher Maria Ermolaeva and Microverse Guest Professor Miguel P. Soares also contributed significantly to the paper.

The paper, recently published in the prestigious academic journal “Trends in Mol Med“, shows that organisms - from simple worms to human cells - exhibit a remarkable phenomenon known as "hormesis". This occurs when the organisms are exposed to low levels of pathogens such as bacteria or viruses. That process triggers a series of adaptive reactions that strengthen the organism's ability to resist subsequent infections, oxidative stress, and other environmental stresses.

"We assume that a low dose of pathogens can trigger the body's defense mechanisms, but also lead to increased resistance and tolerance to future infections," explains Prof. Dr. Michael Bauer. "This is a remarkable example of how organisms have evolved to use mild stresses to their advantage”.

The research team discovered that this hormetic effect involves complicated cellular pathways, including the activation of heat shock proteins, the response to unfolded proteins, and mitochondrial stress responses. These mechanisms help to repair damaged proteins, boost antioxidant defenses, and reprogram cellular metabolism, ultimately increasing the organism's overall fitness and resilience.

Interestingly, the paper also suggests that historical practices such as 'variolation' - the deliberate exposure to tiny amounts of pathogens to generate immunity - may have inadvertently exploited this hormetic phenomenon.

Although further research is needed to understand the implications of these findings fully, the researchers are optimistic about the potential for developing new therapeutic approaches based on hormesis. By targeting stress responses, it may be possible to improve the body's ability to fight infection and promote tissue repair.

“Our research opens up exciting possibilities for using the body’s resistance mechanisms,” explains Maria Ermolaeva, who heads the “Stress Tolerance and Homeostasis” research group at the Leibniz Institute on Aging – Fritz Lipmann Institute. “It could lead to novel treatments that harness the hormetic effects of mild stress, potentially changing our approach to infectious diseases and beyond.”

The joint paper exemplifies the collaboration between basic science and medical application, facilitated by the Microverse Cluster to translate findings into practical use.

Hormesis as an adaptive response to infection
Michael Bauer, Maria Ermolaeva, Mervyn Singer, Reinhard Wetzker, and Miguel P. Soares
Trends Mol Med | May 13, 2024
DOI:https://doi.org/10.1016/j.molmed.2024.04.012