Modulation of oral and gut microbiota with xylitol and 2´fucosyllactose : in vitro studies

The gastrointestinal tract starts at the oral cavity and ends at the colon, and both habitats are heavily colonised with microbes. The microbial communities are modulated by food ingredients such as sugar, xylitol and human milk oligosaccharides (HMOs). This thesis aimed to evaluate: 1) the effects of xylitol and an HMO, 2´-fucosyllactose (2´-FL), on the growth, adhesion and biofilm formation of caries associated bacterium Streptococcus mutans; and 2) the effects of 2´-FL on simulated infant microbiota and metabolite compositions. We utilised in vitro model systems to mimic the oral cavity and colon. The biofilm formation of mutans streptococci was decreased in the presence of xylitol and xylitol mints and increased in the presence of sucrose and sucrose mints. Planktonic S. mutans grew well on galacto-oligosaccharides (GOS), whereas 2´-FL was not utilised by S. mutans as a carbon source, and xylitol inhibited S. mutans growth. The adhesion experiments showed no consistent inhibition patterns for 2´-FL or GOS, and 1% xylitol did not inhibit the adhesion of the S. mutans strains. 2´-FL, GOS and lactose all promoted the growth of bifidobacteria in a simulated infant microbiota experiment. The slight changes in microbiota composition associated with 2´-FL were reflected by the production of short-chain fatty acids and the reduced production of acetate and lactate in the presence of 2´-FL compared with lactose or GOS. The simulations showed differences in 2´-FL fermentation abilities, indicating that 2´-FL fermentation requires specific microbial activity compared with the fermentation of either lactose or GOS. In conclusion, we propose that xylitol can be considered an active ingredient for the inhibition of planktonic S. mutans growth and early biofilm formation. 2´-FL did not support S. mutans growth and thus should not promote unfavourable changes in caries microbiota. Finally, the infant colon and dental simulation models were found to serve as functional models for studying the effects of various food ingredients on bacterial growth, metabolite production and biofilm formation.Ruuansulatus alkaa suusta ja jatkuu ruuansulatuskanavan kautta paksusuoleen. Sekä suussa että suolistossa on tiheä bakteeristo. Mikrobiston koostumusta voi muovata eri ruoka-ainella, kuten sokerilla, ksylitolilla ja äidinmaidon oligosakkarideilla (HMO:lla). Tutkimuksen tavoitteina oli arvioida 1) ksylitolin ja yhden HMO:n 2´¬fukosyylilaktoosin (2´-FL:n) vaikutusta hampaiden reikiintymiseen kytkeytyvän Streptococcus mutans -bakteerin kasvuun, biofilmin muodostumiseen ja kiinnittymiseen pinnoille ja 2) tutkia 2´-FL:n vaikutuksia mallinnettuun vauvan suolistomikrobiston koostumukseen ja sen tuottamiin aineenvaihduntatuotteisiin. Tutkimuksessa käytettiin suuta ja suolistoa jäljitteleviä in vitro malleja. Mutans streptokokkien biofilmin muodostus väheni ksylitolilla ja ksylitoliminttupastilleilla ja lisääntyi sakkaroosilla ja sakkaroosipohjaisilla minttupastilleilla. S. mutans kasvoi hyvin galakto-oligosakkarideilla (GOS:lla), mutta ei 2´-FL:lla ja ksylitol hidasti sen kasvua. Kiinnittymiskokeissa ei löydetty 2´-FL:lle ja GOS:lle samansuuntaista vaikutusta ja 1% ksylitoli ei estänyt S. mutans bakteerin kiinnittymistä. 2´-FL, GOS ja laktoosi, lisäsivät kaikki bifidobakteereiden määrää mallinnetussa vauvan mikrobistossa. Pienet 2´-FL:n aiheuttamat muutokset mikrobistossa näkyivät myös lyhytketjuisten rasvahappojen tuotossa. Mallinnettu mikrobisto muodosti 2´-FL:lla vähemmän asetaattia ja laktaattia kuin GOS:lla ja laktoosilla. Mallinnusten välillä oli eroja 2´-FL n käytössä, mikä viittaa siihen että 2´-FL:n käyttäminen vaatii tarkoin määrätyn mikrobistokoostumuksen verrattuna laktoosiin ja GOS:hin. Yhteenvetona voidaan todeta, että ksylitolia voidaan pitää aktiivisena ruuan ainesosana, joka hidastaa S. mutans:n kasvua ja vähentää biofilmin muodostusta. S. mutans ei kasvanut 2´-FL:lla, mikä viittaa siihen, että sen käytöstä ei seuraa haitallisia vaikutuksia suumikrobiston koostumukseen. Suun biofilmin ja vauvan suolistoa jäljittelevät in vitro mallit todettiin hyödyllisiksi arvioitaessa ruuan ainesosia, joilla voidaan vaikuttaa mikrobiston koostumukseen

Primary reconstruction of combined orbital and zygomatic complex fractures with patient-specific milled titanium implants- A retrospective study

The aim of this retrospective study was to compare mid-facial symmetry and clinical outcomes between patients treated with patient-specific and standard implants in primary fracture reconstructions of combined orbital and zygomaticomaxillary complex fractures.Patients who underwent primary reconstruction of orbital and zygomaticomaxillary complex frac-tures during the study period were identified and background and clinical variables and computed to-mography images were collected from patient records. Zygomaticomaxillary complex dislocation and orbital volume were measured from pre-and postoperative images and compared between groups.Out of 165 primary orbital reconstructions, eight patients treated with patient-specific and 12 pa-tients treated with standard implants were identified with mean follow-up time of was 110 days and 121 days, respectively. Postoperative orbital volume difference was similar between groups (0.2 ml for patient-specific vs 0.3 ml for standard implants, p = 0.942) despite larger preoperative difference in patient-specific implant group (2.1 ml vs 1,5 ml, p = 0.428), although no statistical differences were obtained in symmetricity or accuracy between the reconstruction groups.Within the limitations of the study it seems that patient-specific implants are a viable option for primary reconstructions of combined zygomaticomaxillary complex and orbital fractures, because with patient-specific implants at least as symmetrical results as with standard implants can be obtained in a single surgery.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of European Association for Cranio-Maxillo-Facial Surgery. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).Peer reviewe

Regulation of hBD-2, hBD-3, hCAP18/LL37, and Proinflammatory Cytokine Secretion by Human Milk Oligosaccharides in an Organotypic Oral Mucosal Model

Human milk oligosaccharides (HMOs), the third largest solid fraction in human milk, can modulate inflammation through Toll-like receptor signaling, but little is known about their immunomodulatory potential in the oral cavity. In this study, we determined whether the HMOs 2'-fucosyllactose (2'-FL) and 3-fucosyllactose (3-FL) regulate human-beta defensin (hBD)-2 and -3, cathelicidin (hCAP18/LL-37), and cytokine responses in human gingival cells using a three-dimensional oral mucosal culture model. The model was incubated with 0.1% or 1% 2'-FL and 3-FL, alone and in combination, for 5 or 24 h, and hBD-2, hBD-3, and hCAP18/LL-37 were analyzed by immunohistochemistry. The expression profiles of interleukin (IL)-1, IL-1RA, IL-8, and monocyte chemoattractant protein (MCP)-1 were determined by LUMINEX immunoassay. The combination of 1% 2'-FL and 1% 3-FL, and 1% 3-FL alone, for 24 h upregulated hBD-2 protein expression significantly (p p = 0.016, respectively). No changes in the other antimicrobial peptides or proinflammatory cytokines were observed. Thus, 3-FL, alone and in combination with 2'-FL, stimulates oral mucosal secretion of hBD-2, without effecting a proinflammatory response when studied in an oral mucosal culture model.</p

The use of in vitro model systems to study dental biofilms associated with caries: a short review

A dental biofilm forms a distinct environment where microorganisms live in a matrix of extracellular polysaccharides. The biofilm favors certain bacteria and creates a habitat that functions differently compared to planktonic bacteria. Reproducible model systems which help to address various questions related to biofilm formation, the process of caries development, and its prevention are needed and are continuously developed. Recent research using both batch culture, continuous culture and flow cells in caries biofilm formation is presented. The development of new techniques and equipment has led to a deeper understanding of how caries biofilms function. Biofilm models have also been used in the development of materials inhibiting secondary caries. This short review summarizes available models to study these questions

Xylitol’s Health Benefits beyond Dental Health: A Comprehensive Review

Xylitol has been widely documented to have dental health benefits, such as reducing the risk for dental caries. Here we report on other health benefits that have been investigated for xylitol. In skin, xylitol has been reported to improve barrier function and suppress the growth of potential skin pathogens. As a non-digestible carbohydrate, xylitol enters the colon where it is fermented by members of the colonic microbiota; species of the genus Anaerostipes have been reported to ferment xylitol and produce butyrate. The most common Lactobacillus and Bifidobacterium species do not appear to be able to grow on xylitol. The non-digestible but fermentable nature of xylitol also contributes to a constipation relieving effect and improved bone mineral density. Xylitol also modulates the immune system, which, together with its antimicrobial activity contribute to a reduced respiratory tract infection, sinusitis, and otitis media risk. As a low caloric sweetener, xylitol may contribute to weight management. It has been suggested that xylitol also increases satiety, but these results are not convincing yet. The benefit of xylitol on metabolic health, in addition to the benefit of the mere replacement of sucrose, remains to be determined in humans. Additional health benefits of xylitol have thus been reported and indicate further opportunities but need to be confirmed in human studies