Laboratory of Parasitic therapy (Kateřina Jirků)
Laboratory of Parasitic Therapy focuses on studying intestinal eukaryotes and their siginificance in health and disease. This group of organisms includes intestinal protists and helminths, with the laboratory focusing primarily on commensal and benign species. Although many eukaryotes, especially helminths, have historically been considered pathogens, recent research shows that they play a crucial role in the overall functioning of the intestinal ecosystem, like gut bacteria.
Importance of gut eukaryotes: Intestinal eukaryotes not only support digestion and nutrient absorption but also contribute to the stabilization of intestinal microflora and modulation of the host’s immune system. Modern lifestyle factors such as unbalanced diets, excessive use of antimicrobial agents, high stress levels, and excessive hygiene lead to a reduction in these organisms and their diversity within the gut microbiome. This can cause an imbalance in the intestinal microflora, known as dysbiosis.
Research missions. Currently, our research focuses on two main areas:
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Epidemiological research of intestinal protists in healthy human and animal populations, including their prevalence, genetic diversity, and zoonotic transmission.
- The impact of candidate eukaryotes on inflammatory bowel diseases, such as Crohn’s disease. This is an illness with unclear etiology that is experiencing a global increase in prevalence, especially in industrialized societies, which are characterized by dysbiosis of the intestinal microbiome.
Hypothesis: Our research is based on key theories, including the "Old Friends hypothesis," and the "Biome Depletion theory." These suggest that reduced exposure to natural antigens may disrupt the immune system and increase the incidence of intestinal inflammatory diseases, such as Crohn’s disease. People and animals in industrialized societies have limited contact with intestinal eukaryotes, which may be essential for the proper development and balance of the immune system.
Our research findings: Our findings show that healthy individuals, who do not suffer from intestinal inflammatory diseases, have a higher prevalence of certain intestinal protozoa without exhibiting symptoms. The presence of these organisms is often associated with contact with animals and rural living. Further results suggest that candidate eukaryotes may positively influence inflammatory bowel diseases. Our research contributes to a better understanding of the complexity and relationships within the intestinal microbiome and its impact on human health.
Research projects
Commensal Intestinal Protist: A Part of a Healthy Microbiome?
In recent years, it has become evident that the intestinal microbiome plays a crucial role in our health. However, it is not just bacteria that matter—benign helminths and intestinal protists also play a significant role, becoming an essential part of an optimally functioning gut ecosystem.
One fascinating example is the intestinal protist Blastocystis. This organism was, until recently, primarily associated with severe inflammatory conditions, such as Crohn's disease or irritable bowel syndrome. However, more recent scientific studies, including those focused on healthy individuals, suggest that Blastocystis is more likely a commensal organism—one that lives in harmony with our bodies (e.g., Lhotská et al., 2020, Front Cell Infect Microbiol; Šejnohová et al., 2024, One Health). Despite these findings, comprehensive experimental studies are still lacking to fully elucidate its overall impact on host health, including its effects on the immune system and the composition of the gut microbiome.
To unravel this mystery, we developed a rat model (Růžková et al., 2018, Exp Parasitol), which has already partially demonstrated the beneficial effects of Blastocystis colonization on intestinal inflammatory diseases under certain conditions. We are now focusing on a detailed investigation of how the Blastocystis genome changes during its colonization of the host's gut, which will help us better understand the complex interplay between the gut ecosystem, this protist, and the host's immune system.
Our work doesn't stop here—we are currently engaged in additional projects exploring the role of Blastocystis in human health, in collaboration with clinical institutions.
If you are interested in this project, please contact RNDr. Zuzana Pavlíčková, Ph.D. (zuzana.lhotska@paru.cas.cz).
Intestinal Worms: Surprising Protectors of Our Health
Helminths, commonly known as worms, are often seen as unwanted parasites, but their role in our bodies is far more complex and intriguing. Over hundreds of millions of years of co-evolution with humans and other hosts, these tiny creatures have developed incredibly sophisticated ways to influence our immune system. Rather than merely surviving, helminths actively manipulate the host’s immune response to prevent the inflammation that could destroy them. Although they can be pathogenic under certain conditions, it is becoming clear that the complete disappearance of these organisms from our environment may have serious consequences for our health.
Studies worldwide show that the absence of helminths in the human body is associated with a dramatic increase in chronic inflammatory diseases (CIADs)* in developed countries. These diseases, such as Crohn’s disease, multiple sclerosis, and various allergies, share common risk factors that are particularly prevalent in developed societies.
Recent research on the gut microbiome suggests that reintroducing helminths into the gut ecosystem could be a revolutionary step in treating CIADs. This approach, known as helminth therapy, uses controlled exposure to non-pathogenic or mildly pathogenic worms to activate anti-inflammatory immune responses. Our laboratory is focused on testing the rat tapeworm (Hymenolepis diminuta), which is known for its typically asymptomatic presence in the host organism. Our recent studies have shown that this tapeworm can significantly reduce intestinal inflammation under certain conditions.
Helminth therapy is on the rise, and we are on the brink of new discoveries. To fully understand the interactions between host and helminth, we are investigating how diet composition and other factors affect the efficacy of H. diminuta in treating inflammatory diseases. This tapeworm is emerging as one of the most promising candidates for therapeutic use.
Our research is conducted in collaboration with William Parker’s laboratory at Duke University in the USA, where scientists specialize in studying the effects of H. diminuta on neuropsychiatric disorders, including autism.
If you are interested in this project, please contact MVDr. Kateřina Jirků, Ph.D. (pomajbikova@paru.cas.cz) or RNDr. Milan Jirků (jirku@paru.cas.cz).
*Chronic inflammation-associated diseases (CIADs): refers to a broad class of diseases and conditions caused by chronic inflammation. Accompanied by immune dysregulation, this group of diseases and conditions includes allergies, a range of autoimmune conditions, some neuropsychiatric disorders, and some digestive diseases.
Protists and Human Health: A New Perspective on an Old Coexistence
Scientists have recently discovered that tiny protists residing in our intestines play a crucial role in the health of not only animals but also humans. Unlike the well-known bacteria, intestinal protists remain somewhat of a mystery, especially when it comes to their diversity in Western societies (Lukeš et al., 2015, PLoS Pathog).
For a long time, it was believed that protists were dangerous parasites that needed to be eradicated. However, we now know that many of these organisms are a natural and essential part of a healthy gut microbiome. For example, protists like Blastocystis spp. and Dientamoeba fragilis are much more common in healthy individuals than in those suffering from chronic inflammatory bowel diseases (Lhotská et al., 2020, Front Cell Infect Microbiol; Jirků et al., 2022, Int J of Mol Sci).
Another interesting discovery shows that the presence of these beneficial protists is associated with greater diversity in gut bacteria—a key factor for our health. Our project focuses on monitoring these protists, such as Blastocystis, Dientamoeba, Giardia, Entamoeba, and others, in healthy individuals. Additionally, we are investigating possible transmissions between people and their pets, which could reveal new and important connections.
One of the surprising findings of our research concerns the occurrence of Giardia intestinalis in the healthy population. This protist is commonly detected in patients with clinical symptoms of giardiasis. However, our study revealed that 7% of healthy volunteers in the Czech Republic are asymptomatic carriers of this parasite, which we identified using a sensitive qPCR diagnostic method (Brožová et al., 2023, Emerg Microbes Infect).
Given that protists have been an integral part of the human gut ecosystem throughout evolution, it is time to reconsider their role in the modern world.
If you are interested in this project, please contact RNDr. Kristýna Brožová (kristyna.brozova@paru.cas.cz)
Intestinal Protists in Non-Human Primates
Our laboratory has recently begun focusing on the epidemiology of intestinal protists in non-human primates within zoological gardens. We are particularly interested in protists such as Blastocystis sp., Dientamoeba fragilis, and Giardia intestinalis, which play a key role in the gut microbiome (Šejnohová et al., 2024, One Health). These organisms are gaining increasing attention from scientists, as it becomes evident that their presence can have significant impacts on the health of their hosts, not only in primates but also in the broader context of animal and human populations.
If you are interested in this project, please contact MVDr. Kateřina Jirků, Ph.D. (pomajbikova@paru.cas.cz) or RNDr. Milan Jirků (jirku@paru.cas.cz).
