- Research has suggested that the absence of parasite infections may be linked to an increased prevalence of inflammatory conditions.
- According to a new review of existing studies, parasites may have anti-inflammatory properties that may help prevent aging.
- Controlled restorative therapies can be beneficial for regulating a proper immune response.
Through centuries of evolution, the human body and its surrounding environments have adapted to improve health and promote longevity. For example, the increasing emphasis on hygiene has been effective in combating parasites that cause disease.
These changes have been crucial, as evidenced by the greater life expectancies and lower disease rates in certain regions of the world. However, these benefits come with trade-offs.
Parasites and humans share a long history of coexistence. It is likely that the human immune function developed in relation to parasitic mechanisms.
The “old friends” hypothesis states that these parasites were like old friends of the human body that helped improve tolerance and function and that their decline led to a higher prevalence of allergic responses and autoimmune conditions.
This decline may also promote inflammaging, which is a chronic form of inflammation that worsens with progressing age. Inflammaging contributes to several age-related conditions, such as dementia, cancer, osteoporosis, and heart disease.
One recent study shows that inflammaging may exacerbate symptoms of COVID-19, as well.
Bruce Zhang and Dr. David Gems, from the Institute of Healthy Ageing at University College London in the United Kingdom, conducted a review of the existing literature to explore the use of parasite worms as a therapy to reverse conditions linked to inflammaging. This review article appears in the journal eLife.
The authors focused their research on a specific group of parasitic worms called helminths, which include roundworms, tapeworms, and flukes. These parasites live inside host organisms, such as human bodies, and take advantage of their immune responses in order to survive.
These findings also provide a glimpse into the intricacies of the human body’s immune functions.
Scientists associate the decline of helminths with multiple inflammatory conditions that occur earlier in life. These include asthma, eczema, multiple sclerosis (MS), rheumatoid arthritis, inflammatory bowel disease, and type 1 diabetes.
Current evidence supports the idea that both natural and deliberate infection with helminths can combat these inflammatory conditions.
Indeed, in 1976, researcher J. A. Turton published a report in which he explained that his hookworm infection reduced the severity of his allergies.
A more recent study — which Marc Charabati, of the University of Montreal in Canada, led — showed that infecting mice with helminths eased their MS symptoms.
Although these findings suggest that restorative helminth therapy may address pre-aging inflammatory conditions, the question of whether or not it can prevent conditions that occur in older age remains.
A key characteristic of inflammaging is a consistent increase in pro-inflammatory proteins in the blood. Multiple experiments have shown that helminth infection can suppress levels of these pro-inflammatory proteins.
In contrast, administering anthelmintic treatments — which can kill helminths — increased the inflammatory response of these proteins.
Although the direct administration of helminths can be beneficial, it can also cause undesired infections. A viable alternative is to utilize the molecular components of helminth mechanisms.
One experiment, which Jenny Crowe and others at the University of Glasgow in the U.K. conducted, incorporated this concept in a mouse model that ate a high calorie diet. Specifically, the team administered a protein called ES-62, which is an anti-inflammatory molecule derived from roundworm secretion.
They found that ES-62 prevented both the degradation of the gut barrier and the enlargement of fat tissue, which are mechanisms that contribute to inflammaging.
The mice also showed a 12% increase in their median lifespan. This suggests that ES-62 was able to suppress inflammaging and limit health-related age acceleration.
There is also some evidence that points to helminth therapy in cancer resistance. A few studies in mice have shown that tapeworms prevented the formation of colon tumors.
However, it is important to note that certain helminths can cause cancer, as well. For example, the trematode parasite Schistosoma haematobium can cause bladder cancer.
Although these studies do not confirm that helminths can directly reduce inflammaging, they do show the ability of helminths to protect against the processes that ultimately lead to it.
Zhang and Dr. Gems raise important questions regarding helminth therapy research. These include: “What are optimal ages to apply such therapy to reduce inflammaging? Would helminth therapy act only in a preventive fashion (typical of anti-aging treatments), or could it reverse existing disease symptoms?”
They also state the necessity of understanding the pathways that shape anti-inflammaging properties.
As Dr. Gems says, “In the wake of successes during the last century in eliminating the evils of helminth infections, the time now seems propitious to explore further their possible benefits, particularly for our aging population — strange though this may sound.”