Evaluate and demonstrate the effectiveness of probiotics
An integrated in vitro and in vivo approach favored by TransBIOTech researchers
Probiotics are now at the heart of many innovations in human health. Their potential benefits (modulation of inflammation, improvement of metabolism, and increased resilience to infections) are widely documented in scientific literature. However, transforming these promises into solid evidence remains a major challenge.
The diversity of bacterial strains, the complexity of the gut microbiota, and the multiplicity of mechanisms of action make evaluating the efficacy of probiotics particularly challenging. In this context, it is essential to look beyond marketing claims and rely on rigorous, integrated experimental strategies.
To produce robust and relevant data, TransBIOTech researchers favor an approach that combines in vitro and in vivo testing. This complementary approach makes it possible to decipher the biological mechanisms of probiotics, identify the most promising strains, and better predict their effectiveness in different physiological contexts.
1. In vitro approaches for evaluating the immunomodulatory properties of probiotics
Dendritic cells play a central role in intestinal immunity. Acting as sentinels of the immune system, they capture signals from the intestinal environment and direct the immune response toward either inflammation or tolerance. They therefore provide a relevant model for studying the immunomodulatory properties of probiotics.
In this type of approach, dendritic cells derived from stable cell lines or differentiated from primary human cells are cultured in vitro and exposed to different probiotic strains. The aim is to evaluate their ability to induce the maturation and activation of these cells.
Flow cytometry is used to measure the expression of surface markers associated with the activation and maturation of dendritic cells (CD80, CD86, MHC-II, CD40). At the same time, the production of pro-inflammatory cytokines (TNF, IL-1β, IL-6) or anti-inflammatory cytokines (IL-10, TGF-β) is quantified in the cell supernatant by ELISA. These tests provide a rapid and comparative evaluation of several strains prior to their in vivo validation.
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2. In vivo approaches to evaluate the anti-inflammatory and metabolic impact of probiotics
Mouse models of inflammatory bowel disease
Chronic inflammation is involved in many diseases, including inflammatory bowel disease. Probiotics are frequently studied for their ability to strengthen the integrity of the intestinal barrier and modulate excessive inflammatory responses.
Several mouse models of ulcerative colitis—induced by chemical agents such as sodium dextran sulfate (DSS), trinitrobenzenesulfonic acid (TNBS), or by immune mechanisms such as T-cell transfer—replicate the main characteristics of human pathophysiology.
In these models, the impact of probiotics is assessed using disease activity scores, quantification of systemic or local inflammatory markers, and histological analysis of intestinal tissue integrity. These approaches provide an integrated view of anti-inflammatory mechanisms, from the intestinal epithelium to systemic immunity.
Mouse model of metabolic syndrome
The potential benefits of probiotics are not limited to their anti-inflammatory properties. Numerous studies also suggest a role in preventing or improving metabolic syndrome, characterized by excessive weight gain, insulin resistance, and dyslipidemia (Wieers et al., 2019).
The mouse model of metabolic syndrome induced by a high-fat diet is an ideal tool for studying these effects. Probiotics are administered orally over several weeks, with monitoring of body weight and food consumption. Insulin resistance is assessed using glucose tolerance tests, while repeated blood samples are taken to monitor the lipid profile.
The impact of probiotics on the composition and diversity of the gut microbiota can also be analyzed by sequencing the intestinal contents. At the same time, quantifying metabolic biomarkers such as short-chain fatty acids (SCFAs) provides key information on the functional activity of the microbiota.
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3. Towards a robust and credible scientific demonstration
What this means in practical terms for start-ups and SMEs
The evaluation of probiotic efficacy cannot be reduced to a single test or isolated model. An integrated approach, combining relevant in vitro and in vivo trials, not only provides a better understanding of the specific mechanisms of action of strains, but also allows the most promising candidates to be selected early on in the development process.
For start-ups and SMEs in the biotech, nutraceutical, and foodtech sectors, this strategy represents a key lever:
- reduce scientific risks,
- guide formulation and positioning choices,
- generate credible data for partners, investors, and funding agencies,
- and strengthen the robustness of claims in an increasingly demanding regulatory environment.
Producing robust evidence is no longer an option: it is an essential condition for transforming an innovation into lasting success.
Author: Carole-Ann Huppé, PhD, MBA, Preclinical Pharmacology Researcher, TransBIOTech
Reference: Wieers, G., et al. (2019). How Probiotics Affect the Microbiota. Frontiers in Cellular and Infection Microbiology, 9, 454
