Targeted mutations of genes reveal important roles in palatal development in mice

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the immune system maternal-fetal interface during palatal development

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an important environmental pollutant that disturbs the immune balance of the maternal-fetal interface (MFI) and is also a common environmental factor for the formation of cleft palate (CP). Therefore, the purpose is to investigate whether TCDD can cause CP by disrupting the immune balance of the maternal-fetal interface. Fifteen C57BL/6J mice were randomly assigned to three groups: control group, TCDD group, and TCDD plus Freund's complete adjuvant (FCA) (TCDD + FCA) group. Peripheral blood, placentas, and palatal tissues were collected for H&E, flow cytometry, and ELISA. In the TCDD group, the placental diameter, the number of placental labyrinth vessels, and the area of sponge layer cells were all significantly reduced. At embryonic day (E) 17.0, there was a significant decrease in T-helper 1 (Th1) and Th2 cells in the peripheral blood of pregnant mice. Additionally, the levels of interferon-γ (IFN-γ) and interleukin-4 (IL-4), particularly IL-4, were significantly decreased. However, after treatment with FCA, the distance between the palatal shelves was reduced, and the placental weight, the number of labyrinth vessels, and the area of the cavernous cells in the placenta also increased. The number of Th1 and Th2 cells significantly increased, returning to the levels observed in the control group, with a more pronounced increase in the number of Th2 cells. In conclusion, TCDD may induce CP by disrupting the homeostasis of the MFI. The precise mechanisms by which TCDD impacts the immune system at the MFI require further investigation.2,3,7,8-- （TCDD） ， （MFI） ， （CP） 。， TCDD CP。 15 C57BL/6J 3 ：、TCDD TCDD （FCA） （TCDD + FCA） 。、 H&E、 ELISA。TCDD 、。 17.0 （E） ， T 1 （Th1） Th2 。，-γ （IFN-γ） -4 （IL-4）， IL-4 。， FCA ，，、。Th1 Th2 ，，Th2 。，TCDD MFI CP。TCDD MFI 。.

Assessment of the Mandibular Osseous Architecture in Cleft Lip and Palate Using Fractal Dimension Analysis: A Pilot Study

Background/Objectives: Although there has been extensive research on the orofacial morphologic effects of cleft lip and palate (CLP), the effects of CLP on mandibular structures remain largely unknown. The aim of this study was to investigate the trabeculation differences in the mandibular osseous architecture of patients with bilateral CLP (BCLP) and left-sided unilateral CLP (UCLP) using fractal dimension (FD) analysis and to compare these findings with healthy controls without CLP. Methods: A total of 63 patients (27 females, 36 males) with a mean age of 9.69 ± 1.5 years in the pre-peak growth stage were divided into three groups (n = 21 per group): the control group (CG), the BCLP group, and the UCLP group. The FD analysis was conducted on selected regions of interest (ROIs) from the mandibular condyle, angulus, corpus, and coronoid areas in TIFF-formatted panoramic radiographs. Statistical analyses were performed using the paired t-test and ANOVA for parametric data, and the Wilcoxon and Kruskal-Wallis tests for nonparametric data. Statistical significance was set at p < 0.05. Results: The FD values obtained from the ROIs of the right condyle were found to be significantly lower in the BCLP group compared to the CG and UCLP groups (p < 0.05). Conversely, the FD values for the left condyle were significantly higher in the CG group (p < 0.05), while no significant differences were observed between the BCLP and UCLP groups (p > 0.05). The FD value of the left condyle in the UCLP group was found to be significantly lower than that of the right condyle (p < 0.05). In the CG group, the FD values for both the right and left mandibular condyle and corpus were significantly higher than those for the angulus and coronoid regions; in the UCLP group, only the FD values of the right mandibular condyle and corpus were significantly higher than those for the same regions (p < 0.05). Conclusions: The reduced FD values in the mandibular condyle of CLP patients during the pre-peak growth stage suggest a loss of trabeculation and lower metabolic activity, while similarly, reduced FD values in the corpus region contribute to delayed tooth eruption timing, likely due to decreased masticatory forces during the intercuspal position and altered occlusal relationships. Clinical Relevance: In treating CLP patients, particularly with orthopedic face masks, the reduction in metabolic activities in these areas should be considered to achieve the optimal mandibular growth and development, and dental eruptions during the distribution of force from the chin to the corpus and condyle.

The Effects of Presurgical Orthodontic Treatment on the Outcome of Secondary Bone Graft for Individuals With Cleft Lip and Palate

BACKGROUND/OBJECTIVE

Alveolar bone graft (ABG) or repair has become a routine part of treatment protocols for individuals with cleft lip and/or palate. However, the necessity and potential benefits of presurgical orthodontic treatment in influencing the outcomes of secondary alveolar bone grafting remain inconclusive. This systematic review aimed to assess the impact of presurgical orthodontics on preparing patients for secondary alveolar bone grafts.

STUDY DESIGN

The authors systematically searched for relevant articles in PubMed, Web of Science, and Embase databases spanning the period from January 1, 2000, to December 31, 2023, using keywords related to alveolar bone grafting and orthodontic treatment for patients with cleft lip and/or palate. The review encompassed various study designs, including prospective and retrospective studies, observational studies, cross-sectional studies, randomized and nonrandomized clinical trials, cohort studies, and case-control studies. The review adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and the risk of bias was evaluated in studies selected for full-text review.

RESULTS

The search strategy identified 809 publications. After initial screening and application of exclusion criteria, 11 studies were included for final review. Three were prospective studies, 8 were retrospective studies, and 3 were cross-sectional cohort studies. On the basis of ROBINS-I and RoB 2 risk assessment, 9 studies were found to be of moderate risk of bias, one study was categorized as of high risk of bias, and 1 study was categorized as low risk of bias.

CONCLUSIONS

Drawing from the latest and most reliable studies, 7 out of 11 included studies provided compelling evidence that presurgical orthodontics preceding alveolar bone grafting (ABG) leads to significantly improved outcomes compared with cases without presurgical orthodontic intervention. Notably, individuals with specific conditions, such as severely collapsed upper arch and mispositioned upper incisors, appear to derive the greatest benefits from presurgical orthodontic treatment. However, a call for additional studies characterized by high methodological quality and with longer follow-up periods is emphasized to enhance the safety considerations for both practitioners and patients concerning the utilization of presurgical orthodontics in the treatment of individuals with cleft lip and palate.

Genetic Variants in Mammalian STE20-like Protein Kinase 2 were associated with risk of NSCL/P

AIM

Mammalian STE20-like protein kinase 2 (MST2) plays an important role in apoptosis and the development of many disorders. Here, we aim to explore if genetic variants in MST2 are associated with the risk of non-syndromic cleft lip with or without palate (NSCL/P).

MATERIALS AND METHODS

The association study was performed in a two-stage study of 1,069 cases and 1,724 controls to evaluate the association between genetic variants in the MST2 and NSCL/P risk. The potential function of the candidate single nucleotide polymorphism (SNP) was predicted using HaploReg, RegulomeDB, and public craniofacial histone chromatin immunoprecipitation sequencing (ChIP-seq) data. Haploview was used to perform the haplotype of risk alleles. The expression quantitative trait loci (eQTL) effect was assessed using the Genotype-Tissue Expression (GTEx) project. Gene expression in mouse embryo tissue was performed using data downloaded from GSE67985. The potential role of candidate gene in the development of NSCL/P was assessed by correlation and enrichment analysis.

RESULTS

Among SNPs in MST2, rs2922070 C allele (P_meta = 2.93E-04) and rs6988087 T allele (P_meta = 1.57E-03) were linked with significantly increased risk of NSCL/P. Rs2922070, rs6988087 and their high linkage disequilibrium (LD) SNPs constituted a risk haplotype of NSCL/P. Individuals carrying 3-4 risk alleles had an elevated risk of NSCL/P compared to those who carried less risk alleles (P = 2.00E-04). The eQTL analysis revealed a significant association between these two variants and MST2 in muscle tissue of the body. The MST2 expressed during mouse craniofacial development and over-expressed in the human orbicularis oris muscle (OOM) of NSCL/P patients compared to controls. MST2 was involved in the development of NSCL/P by regulating the mRNA surveillance pathway, the MAPK signaling pathway, the neurotrophin signaling pathway, the FoxO signaling pathway and the VEGF signaling pathway.

CONCLUSION

MST2 was associated with the development of NSCL/P.

Effectiveness of presurgical orthodontics in cleft lip and palate patients with alveolar bone grafting: A systematic review

OBJECTIVE

Alveolar repair has become a routine part of treatment protocols for patients with non-syndromic cleft lip and/or palate, but there is no clear conclusion of whether the presurgical orthodontic treatment is necessary to alveolar bone grafting or not. The purpose was to determine the necessity of the presurgical orthodontics in cleft lip and palate patients.

MATERIALS AND METHODS

Electronic databases including PubMed, Ovid, Embase, Cochrane Library, Web of Knowledge, and China Biology Medicine disc (SinoMed) were searched. Only studies published in English or Chinese were included. The last search was updated on 1 May 2020. 1225 articles remaining after the exclusion of duplicates. Finally, there were 11 publications (five in English and six in Chinese) eligible for systematic review according to the previously established inclusion and exclusion criteria. A descriptive statistical method was used to present data. The methodological index for non-randomized studies (MINORS) was used to determine the risk of bias.

RESULT

Eleven articles were included in this review, of which seven publications were retrospective study and four articles were comparative study. The average success rate of reconstruction with the presurgical orthodontic treatment was approximately 70-97%, while the success rate of the non-presurgical orthodontics was 25-80%. The fixed and removable presurgical orthodontic methods were frequently performed, rather than a single treatment model. The incidence of the postoperative complications resulting from whether adopting the presurgical orthodontics was different from none to 75%.

CONCLUSION

There are a higher postoperative bone formation rate and a lower complication rate after ABG with presurgical orthodontics. However, more studies with high methodological quality and with a longer follow-up are needed to offer more safety for practitioners and patients regarding the surgical method selected to repair the cleft alveolar.

Effectiveness of corticocancellous bone graft in cleft lip and palate patients: A systematic review

OBJECTIVE

Both cancellous bone graft and corticocancellous bone graft are the most common grafts for repairing alveolar cleft, but there is no clear conclusion as to which method is beneficial to repair the alveolar cleft. The aim was to determine the effectiveness of corticocancellous bone graft in cleft lip and palate patients.

MATERIALS AND METHODS

Electronic databases including PubMed, Ovid, Embase, Cochrane Library, Web of Knowledge, and China Biology Medicine disc (SinoMed) were searched. Only studies published in English or Chinese were included. The last search was updated on 1 January 2020. 2638 articles remaining after the exclusion of duplicates. Finally, there were 16 publications (15 in English and 3 in Chinese) eligible for systematic review according to the previously established inclusion and exclusion criteria. A descriptive statistical method was used to present data. The methodological index for non-randomized studies (MINORS) was used to determine the risk of bias.

RESULT

Sixteen articles were included in this review, of which 15 publications were retrospective study and one was a comparative study. The average success rate of reconstruction with block bone was approximately 90.8%, while the success rate of the cancellous bone graft was about 85.3%. The incidence of wound dehiscence was approximately 10% to 16%, and infection is about 9% to 20%. The incidence of oronasal fistula resulting from severe bone resorption and infection was approximately 7.5% to 10.5%.

CONCLUSION

There is a higher bone formation rate of corticocancellous bone graft in patients with the alveolar cleft. However, more studies with high methodological quality and with a longer follow-up are needed to offer more safety for practitioners and patients regarding the surgical method selected to repair the cleft alveolar.

Closing the Gap: Mouse Models to Study Adhesion in Secondary Palatogenesis

Secondary palatogenesis occurs when the bilateral palatal shelves (PS), arising from maxillary prominences, fuse at the midline, forming the hard and soft palate. This embryonic phenomenon involves a complex array of morphogenetic events that require coordinated proliferation, apoptosis, migration, and adhesion in the PS epithelia and underlying mesenchyme. When the delicate process of craniofacial morphogenesis is disrupted, the result is orofacial clefting, including cleft lip and cleft palate (CL/P). Through human genetic and animal studies, there are now hundreds of known genetic alternations associated with orofacial clefts; so, it is not surprising that CL/P is among the most common of all birth defects. In recent years, in vitro cell-based assays, ex vivo palate cultures, and genetically engineered animal models have advanced our understanding of the developmental and cell biological pathways that contribute to palate closure. This is particularly true for the areas of PS patterning and growth as well as medial epithelial seam dissolution during palatal fusion. Here, we focus on epithelial cell-cell adhesion, a critical but understudied process in secondary palatogenesis, and provide a review of the available tools and mouse models to better understand this phenomenon.