Living Bacterial Sacrificial Porogens to Engineer Decellularized Porous Scaffolds

Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types

Improvement of an experimental model of oral biofilm

Objectives: The main aim of our work was to get one step closer to the in vivo conditions. We started from a multispecies static biofilm model containing five different bacteria, implementing specific enhancements. Our second goal was to improve the analysis of such biofilms regarding collection and identification. Material and Methods: We started from a multispecies static model with five oral strains growing on hydroxyapatite discs to improve it on multiple points. We modified culture conditions and added two more strains. We also changed bacteria collection, which evolved from manually scrapping the discs surface to the combination of ultrasonic and mechanical harvesting. In a further another step, we developed a dynamic model implementing the above changes with a continuous supply of medium flow and waste disposal. Different methods have been evaluated to monitor the presence of all the species within the biofilms, and to quantify them: gram staining, PCR, MALDI-TOF-MS, qPCR. Results: The modifications brought to our static model confirmed its reproducibility. Even if improvements need to be made, our dynamic model of oral biofilm is already a good alternative to more sophisticated and expensive models. Conclusions: This new oral biofilm model represents the premises of another way to study the environmental variations effects on bacterial development, its larger application will result in a better understanding of oral health significant factors

Rev Epidemiol Sante Publique

Position du problème Les personnes âgées constituent une proportion croissante de la population européenne mais leur profil épidémiologique bucco-dentaire est mal documenté. Les objectifs de cette étude étaient d’évaluer l’état bucco-dentaire des personnes âgées de 90 ans et plus en France, de comparer leurs besoins en soins bucco-dentaires perçus et observés, et d’identifier les problèmes bucco-dentaires associés à une faible qualité de vie liée à la santé bucco-dentaire (QdVSBD). Méthodes Une étude transversale bucco-dentaire a été réalisée lors du 25e suivi d’une cohorte de personnes âgées en Gironde et en Dordogne. Les indices bucco-dentaires ont été recueillis lors d’examens cliniques effectués au domicile des participants. L’accord entre les besoins perçus et observés a été évalué avec le coefficient de Kappa de Cohen. Les problèmes bucco-dentaires associés à une faible QdVSBD ont été identifiés par régression logistique. Résultats Les données de 90 personnes ont été analysées (76% de femmes ; âge médian = 93 ans ; 20% vivant en institution). La plaque et le tartre étaient présents chez respectivement 93% et 58% des 74 participants dentés. Le nombre moyen de dents cariées, manquantes et obturées était de 26,5 (± 5,3) ; 66% des participants avaient au moins une dent cariée non traitée. Parmi les 85 participants avec édentement non compensé par prothèse fixée, deux tiers avaient une prothèse amovible ; 84% de ces prothèses étaient considérées comme inadaptées. Consulter un dentiste présentait des obstacles pour 43% des participants, citant le plus souvent le manque de moyens de transport. Bien que 88% des participants aient eu besoin de soins bucco-dentaires, seuls 26% le percevaient (Kappa = 0,06). L’absence d’occlusion postérieure (odds ratio [OR] = 7,15 ; intervalle de confiance [IC] à 95% = 1,53–33,35 ; p = 0,012), la sensation de bouche sèche (OR = 11,94 ; IC 95% = 3,21–44,39 ; p = 0,0002) et une douleur orale (OR = 9,06 ; IC 95% = 1,91–69,00 ; p = 0,033) étaient associées à une faible QdVSBD. Conclusion Les personnes de 90 ans et plus ont d’importants besoins bucco-dentaires préventifs et curatifs qui ont un impact sur leur qualité de vie, mais elles sont rarement au courant et manquent de moyens de transport.Background Older persons comprise a growing proportion of the European population and may have a distinct epidemiological oral profile requiring specific preventive and curative care poorly documented. The objectives of this study were to assess the oral health status of people ≥ 90 years of age in France, to compare their perceived and observed oral care needs and to investigate the oral problems associated with a low oral health-related quality-of-life (OHRQoL). Methods An oral cross-sectional study was performed during the 25th follow-up of a cohort of older persons being followed up prospectively for screening of dementia over a 15-year period in Gironde and Dordogne, France. Clinical oral indices were determined by oral examinations conducted at the participants’ place of living. Cohen's Kappa coefficient was used to assess the agreement between perceived and observed oral care needs. Oral problems associated with a low OHRQoL, measured with the Geriatric Oral Health Assessment Index (GOHAI < 50) were investigated with logistic regression. Odds ratios (OR) were estimated with their 95% confidence intervals (CI). Results Data from 90 persons were analysed (76% female; median age = 93 years; 20% living in an institution). Plaque and calculus were present in 93% and 58% respectively, of the 74 dentate participants. The mean number of decayed, missing, and filled teeth was 26.5 (± 5.3); 66% of the participants had at least one untreated decayed tooth. Among the 85 participants with tooth loss not replaced by a fixed denture, two thirds had a removable dental prosthesis; 84% of these prostheses were considered to be maladapted. Among the 39 participants who felt unable to consult a dentist (43%), lack of transportation was the most frequently cited reason. Although 88% of the participants needed oral care, only 26% perceived that they had such a need (Kappa = 0.06). Oral problems associated with a GOHAI < 50 were the absence of posterior occluding teeth (OR = 7.15; 95%CI = 1.53–33.35; P = 0.012), feeling of dry mouth (OR = 11.94; 95%CI = 3.21–44.39; P = 0.0002) and oral pain (OR = 9.06; 95%CI = 1.91–69.00; P = 0.033). Conclusions Persons ≥ 90 years of age have considerable preventive and curative dental care needs that impact their quality-of-life but they are rarely aware and lack transportation. NCT04065828