Gli1+ Periodontal Mesenchymal Stem Cells in Periodontitis.

Periodontal mesenchymal stem cells (MSCs) play a crucial role in maintaining periodontium homeostasis and in tissue repair. However, little is known about how periodontal MSCs in vivo respond under periodontal disease conditions, posing a challenge for periodontium tissue regeneration. In this study, Gli1 was used as a periodontal MSC marker and combined with a Gli1-cre ERT2 mouse model for lineage tracing to investigate periodontal MSC fate in an induced periodontitis model. Our findings show significant changes in the number and contribution of Gli1+ MSCs within the inflamed periodontium. The number of Gli1+ MSCs that contributed to periodontal ligament homeostasis decreased in the periodontitis-induced teeth. While the proliferation of Gli1+ MSCs had no significant difference between the periodontitis and the control groups, more Gli1+ MSCs underwent apoptosis in diseased teeth. In addition, the number of Gli1+ MSCs for osteogenic differentiation decreased during the progression of periodontitis. Following tooth extraction, the contribution of Gli1+ MSCs to the tooth socket repair was significantly reduced in the periodontitis-induced teeth. Collectively, these findings indicate that the function of Gli1+ MSCs in periodontitis was compromised, including reduced contribution to periodontium homeostasis and impaired injury response.

Asociación entre enfermedad periodontal y parto pretérmino en un grupo de mujeres puérperas del norte de México / Association between periodontal disease and preterm birth in a group of puerperal women from northern of Mexico

Introducción: La enfermedad periodontal puede ser causa de lesiones sistémicas. Se conoce la prevalencia de enfermedad periodontal en mayores de 35 años y el aumento de los factores de riesgo en mujeres embarazadas, pero no se sabe si estos factores se potencializan en mujeres embarazadas menores de 35 años. En México son muy prevalentes tanto el embarazo en mujeres jóvenes como el parto pretérmino. Con el objetivo de conocer la prevalencia de la enfermedad periodontal y su asociación con el parto prematuro, se realizó este estudio en mujeres puérperas menores de 35 años en una población abierta. Material y métodos: Estudio de tipo observacional, descriptivo y transversal, analizando casos y controles. La población de estudio fueron pacientes puérperas entre 17 y 35 años que ingresaron a un hospital público durante parte del año 2019. Se utilizó el índice de necesidad de tratamiento periodontal en la comunidad (CPITN, por sus siglas en inglés) para la medición de enfermedad periodontal (EP), se consideró embarazo prematuro (PP) cuando el parto ocurrió con menos de 37 semanas de embarazo. Como covariables se consideraron edad, tabaquismo y paridad. Se buscó la asociación mediante regresión logística para el cálculo de la razón de momios. Resultados: Se analizaron 323 mujeres, 200 (62%) tuvieron niveles 3 y 4 CPITN; 10.8% (35) tuvieron parto prematuro, la razón de momios cruda para la asociación entre código CPITN 3 y 4 y parto prematuro fue de 3.3 (p < 0.01). Después de ajustar por otros predictores la asociación se mantuvo en 3.8 (p < 0.01). Conclusiones: Es la primera vez en nuestro medio que se encuentra esta asociación entre enfermedad periodontal y parto prematuro. La prevalencia de parto prematuro en este grupo fue más alta que la media nacional. Es necesaria la revisión odontológica durante las visitas prenatales. Debe continuarse la línea de investigación con un estudio prospectivo (AU)

Introduction: Periodontal disease can cause systemic injuries. Prevalence of periodontal disease in people older than 35 years old is known, as well as the risk factors for pregnant women; however, it is not known if these factors also apply for pregnant women younger than 35 years of age. In Mexico, pregnancy among young women and preterm birth are very prevalent. The present study was done with the objective of finding out the prevalence of periodontal disease and its relationship with preterm birth in puerperal women younger than 35 years old in a population without social security. Material and methods: The study is observational, descriptive and transversal, analysis type cases and controls was done. The population for the study consists on puerperal patients between the ages of 17 to 35 years, all of them were admitted into a public hospital in a period of 2019. The Community Periodontal Index of Treatment Need (CPITN) was used to measure periodontal disease in the patients. Preterm birth was defined as a birth occur before 37 weeks of pregnancy. Age, smoking and parity were used as covariables. Logistic regression was used to evaluate the association between periodontal disease and preterm birth through odds ratio values. Results: 323 women were analyzed, 200 (62%) had levels of 3 and 4 on the CPITN. 10.8% (35) had preterm birth, the raw odds ratio for the association between the codes 3 and 4 from the CPITN was of 3.3 (p < 0.01), after adjusting other predictors the association was 3.8 (remaining as a p < 0.01). Conclusions: It is the first time that such an association between periodontal disease and preterm birth has been found in the region. Prevalence of preterm birth in the group studied was higher than the national's average. An odontological revision during prenatal visits is needed. This line of research should be continued through a prospective study (AU)

Fusobacterium nucleatum activates the immune response through retinoic acid-inducible gene I.

Retinoic acid-inducible gene I (RIG-I) is a cytosolic pattern recognition receptor involved in the sensing of RNA viruses and the initiation of antiviral responses. Fusobacterium nucleatum, a Gram-negative anaerobic bacterium associated with periodontal disease, is capable of invading cells. We hypothesized that F. nucleatum's ability to invade cells allows the microorganism to activate the immune response through RIG-I. Bacterial invasion was found to be necessary for F. nucleatum-induced nuclear factor kappa B (NF-κB) activation. Following invasion of the human periodontal ligament fibroblast (PDLF), F. nucleatum was located in the cytosol. F. nucleatum infection led to an 80-fold increase in RIG-I expression. Silencing RIG-I in PDLF by siRNA led to a significant decrease of NF-κB activation and expression of proinflammatory genes. Additionally, F. nucleatum was able to secrete nucleic acids, and introduction of F. nucleatum RNA into PDLF led to a RIG-I-dependent activation of NF-κB. Our findings showed RIG-I to be involved in the recognition of F. nucleatum. The function of RIG-I is likely to be broad and not limited to sensing of viruses only. Hence, this receptor may play an important role in detecting invasive forms of oral pathogens and contribute to inflammation in periodontal tissues.