Non-viable preparations of probiotics, as whole-cell postbiotics, attract increasing interest because of their intrinsic technological stability, and their functional properties, such as immune system modulation, gut barrier maintenance, and protection against pathogens. However, reports on Bifidobacteria-derived postbiotics remain scarce. This study aims to demonstrate the functional properties of a heat-treated (HT), non-viable, Bifidobacterium longum strain, CECT-7347, a strain previously selected for its anti-inflammatory phenotype and ability to improve biomarkers of intestinal integrity in clinical trials. The study used the nematode Caenorhabditis elegans and HT-29 cell cultures as eukaryotic model systems. Our results show that HT-CECT-7347 preserves the capacity to protect against oxidative stress damage, while it also reduces acute inflammatory response and gut-barrier disruption, and inhibits bacterial colonization, by activating pathways related to innate immune function. These findings highlight the interest of the ingredient as a novel postbiotic and pave the way to broaden the range of HT-CECT-7347 applications in gut health.

Canine osteoarthritis is a progressive degenerative joint condition characterized by inflammation, structural damage, pain, and impaired joint function. Osteoarthritis risk is influenced not only by well-established factors such as age, genetics, obesity and underlying arthropathies, but also by systemic conditions such as low-grade inflammation and sarcopenia. Current interventions are primarily focused on pain relief rather than mitigating physiological impairment, despite recent veterinary guidelines. In this study, several preclinical models were employed to identify postbiotic candidates with potential to promote canine joint health. An initial screening of nine heat-treated bacterial strains identified two Lacticaseibacillus rhamnosus strains, PRIOME^® JH and HT-PB01, which demonstrated significant anti-inflammatory activity on canine chondrocytes. Further characterization revealed that these two strains significantly increased type II collagen synthesis in canine chondrocytes and modulate immune responses in canine macrophages, enhancing Interleukin-10 secretion over Interleukin-12. Additionally, both strains showed potential in mitigating risk factors such as gut inflammation and permeability, fat accumulation and sarcopenia in Caenorhabditis elegans models. In conclusion, this study identified two promising postbiotic candidates, PRIOME^® JH and HT-PB01, with the potential to target key risk factors associated with osteoarthritis through multifactorial mechanisms. These findings emphasize conducting dog clinical trials to evaluate their relevance in osteoarthritis.

In a previous clinical trial, it was shown that a probiotic blend (Bifidobacterium longum CECT 7347 (Esflorin1™), Lacticaseibacillus rhamnosus CECT 8361 (BPL15) and Lacticaseibacillus casei CECT 9104 (BPL4)) reduced oxidative stress in males engaging in intense exercise. The present study evaluated whether the probiotic blend’s functional properties are preserved after heat treatment and investigated the underlying mechanism of action using preclinical models. The antioxidant, immunomodulatory and intestinal effects of the heat-treated and probiotic blends were assed using in vitro assays and Caenorhabditis elegans (C. elegans) models. The heat-treated blend preserved the antioxidant activity by scavenging free radicals, reducing intracellular reactive oxygen species and enhancing survival in C. elegans under oxidative stress, possibly via sod-3 upregulation in the CF1553 strain. It also enhanced mitochondrial biogenesis and ATP production in C2C12 via AMPK phosphorylation. Both versions attenuated a gut inflammatory response, improved intestinal barrier in Caco-2 cells and C. elegans and exhibited immunomodulatory activity in U937 macrophages at the tested concentrations. These findings support the heat-treated blend as a promising postbiotic supplement to manage oxidative stress and other physiological alterations associated with intense exercise.