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Knowing that Rhodomyrtus tomentosa is known to have antibacterial effects, this study investigated the skin microbiota with a focus on Cutibacterium acnes (C. acnes) phylotypes in subjects with acne, and determined microbiota changes after 28 days of treatment with berries Rhodomyrtus tomentosa as an active ingredient (RT). Skin swabs from seventeen acne subjects were collected and the skin microbiome was analyzed using 16S rRNA gene sequencing. A culture-independent next-generation sequencing (NGS)-based SLST (single-locus sequence typing) approach was aimed at evaluating RT extract effects on C. acnes phylotype repartition. Clinical evaluations (lesion counts) were performed at baseline (D0) and after 28 days (D28) of twice-daily application of the RT active ingredient. We determined: (1) the skin microbiota at D0 was dominated by Actinobacteria followed by Firmicutes and Proteobacteria, (2) at the genus level, Cutibacterium was the most abundant genus followed by Staphylococcus and Corynebacterium, (3) C. acnes was the major species in terms of mean abundance, followed by Staphylococcus epidermidis (S. epidermidis) and Staphylococcus hominis (S. hominis), and (4) phylotype IA1 was most represented, with a predominance of SLST type A1, followed by phylotypes II, IB, IA2, IC, and III. After 28 days of RT extract treatment, phylotype repartition were modified with a decrease in abundance (approximately 4%) of phylotype IA1 and an increase in phylotype II and III. Cutibacterium granulosum (C. granulosum) abundance also decreased. Reduction of retentional and inflammatory lesions was also noted only after RT treatment, thus, RT extract acts as a microbiota-regulating agent.

International audience; Among the various regulators of the nervous system, the gut microbiota has been recently described to have the potential to modulate neuronal cells activation. While bacteria-derived products can induce aversive responses and influence pain perception, recent work suggests that "abnormal" microbiota is associated with neurological diseases such as Alzheimer's, Parkinson's disease or autism spectrum disorder (ASD). Here we review how the gut microbiota modulates afferent sensory neurons function and pain, highlighting the role of the microbiota/gut/brain axis in the control of behaviors and neurological diseases. We outline the changes in gut microbiota, known as dysbiosis, and their influence on painful gastrointestinal disorders. Furthermore, both direct host/microbiota interaction that implicates activation of "pain-sensing" neurons by metabolites, or indirect communication via immune activation is discussed. Finally, treatment options targeting the gut microbiota, including pre- or probiotics, will be proposed. Further studies on microbiota/nervous system interaction should lead to the identification of novel microbial ligands and host receptor-targeted drugs, which could ultimately improve chronic pain management and well-being.

Intrinsic skin ageing is mainly caused by cellular senescence. p16 and p21 are two important tumour suppressor proteins that play essential roles during cell proliferation and ageing through regulating the expression of several genes. Moreover, physical changes between the ages of 55 and 60 years affect one's physical and disrupt self-esteem. The cosmetics industry has focused on bioactive substances derived from natural products such as plants, mushrooms and marine algae to counteract the deleterious effect on skin senescence. Besides these products, compounds produced by bacteria may decelerate individual senescence.In order to evaluate the potential benefits of bacteria extract over skin ageing, we investigated whether a Sphingomonas hydrophobicum (SH) extract is able to protect our skin against senescence mechanisms. We used an ageing full-thickness skin equivalent model, which was treated or not with the bacteria extract in a systemic way for 42 days. p21 and p16 and senescence-associated galactosidase activity were used to detect cellular senescence with immunohistology. Using a psychobiological approach, we evaluated in vivo the effect of SH extract on self-esteem, isotropy and suppleness.Sphingomonas extract significantly suppressed senescence associated with β-galactosidase activation. It also significantly inhibited the expression of cell cycle inhibitors (p21 and p16). At the same time, the bacteria extract has a significant positive impact on the issue by increasing the expression of versican and fibrillin-1. Significant improvements of self-esteem were reported after 56 days of SH extract application. These psychological benefits were accompanied by a significant improvement in skin suppleness and isotropy.Sphingomonas extract delays intrinsic skin ageing process by inhibiting cellular senescence, and has also the capability to restructure the skin. These beneficial physiological effects induced by SH extract have a positive influence on self-esteem. Because skin ageing causes emotional distress, SH extract can serve as an anti-ageing cosmeceutical agent and help to build a better psychological health, and help individuals to assume ageing.Le vieillissement intrinsèque de la peau est principalement causé par la sénescence cellulaire. p16 et p21 sont deux importantes protéines suppressives de tumeurs qui jouent un rôle essentiel dans la prolifération et le vieillissement cellulaire en régulant l'expression de plusieurs gènes. De plus, les changements physiques survenant entre 55 et 60 ans affectent le physique et perturbent l'estime de soi. L'industrie cosmétique s'est concentrée sur les substances bioactives dérivées de produits naturels tels que les plantes, les champignons et les algues marines pour contrer les effets délétères sur la sénescence de la peau. En plus de ces produits, les composés produits par les bactéries peuvent ralentir la sénescence individuelle. MÉTHODES: Afin d’évaluer les bénéfices potentiels de l'extrait de bactérie sur le vieillissement cutané, nous avons étudié si un extrait de Sphingomonas hydrophobicum (SH) est capable de protéger notre peau des mécanismes de sénescence. Nous avons utilisé un modèle équivalent de peau vieillissante de pleine épaisseur, qui a été traitée ou non avec l'extrait de bactérie de façon systémique pendant 42 jours. p21 et p16, et l'activité galactosidase associée à la sénescence ont été utilisés pour détecter la sénescence cellulaire par immunohistologie. En utilisant une approche psychobiologique, nous avons évalué in vivo l'effet de l'extrait de SH sur l'estime de soi, l'isotropie et la souplesse. RÉSULTATS: L'extrait de Sphingomonas a considérablement supprimé la sénescence associée à l'activation de β-galactosidase. Il a également inhibé de manière significative l'expression des inhibiteurs du cycle cellulaire (p21 et p16). En même temps, l'extrait de bactérie a un impact positif significatif sur le problème en augmentant l'expression du versican et de la fibrilline-1. Des améliorations significatives de l'estime de soi ont été rapportées après 56 jours d'application de l'extrait de SH. Ces bienfaits psychologiques s'accompagnaient d'une amélioration significative de la souplesse et de l'isotropie de la peau.L'extrait de Sphingomonas retarde le processus de vieillissement intrinsèque de la peau en inhibant la sénescence cellulaire et a également la capacité de restructurer la peau. Ces effets physiologiques bénéfiques induits par l'extrait de SH ont une influence positive sur l'estime de soi. Parce que le vieillissement de la peau provoque une détresse émotionnelle, l'extrait de SH peut servir d'agent cosméceutique anti-âge et aider à construire une meilleure santé psychologique, ainsi qu'aider les individus à assumer le vieillissement.