Prevalence and Risk Factors for Obstructive Sleep Apnea Syndrome Among Children and Adolescents with Cleft lip and Palate: A Survey Study in Hong Kong

Objective To investigate the prevalence of obstructive sleep apnea syndrome (OSAS) risk and related risk factors among children and adolescents of Hong Kong with cleft lip and/or palate (CL/P). Design Retrospective survey study adopting three questionnaires, obstructive sleep apnea-18 (OSA-18), pediatric sleep questionnaire-22 (PSQ-22), and modified Epworth Sleepiness Scale (ESS). Settings Multicenter study in two public hospitals. Patients A total of 351 Chinese children and adolescents with non-syndromic CL/P (6-18-year-old, 57% males) visited between September 2017 and November 2019, with primary palatal repair surgery done before 3-year-old. Main Outcome Measure Positive OSAS risk was determined based on cut-off ≥60 for OSA-18, ≥8 for PSQ-22, and >8 for ESS. Age, sex, overweight presence, cleft type, embryonic secondary palate involvement, palatal repair surgery, palatal revision surgery, and orthodontic treatment were analyzed as possible risk factors. Results A total of 9.5% of patients had positive OSAS risk based on OSA-18, 13.6% based on PSQ-22, and 13.2% according to ESS. A higher prevalence of patients with positive OSAS risk was of younger age (OSA-18, p = .034), had cleft involving embryonic secondary palate (PSQ-22, p = .009), and history of fixed orthodontic treatment (ESS, p = .002). The regression model identified only involvement of embryonic secondary palate as a risk factor (PSQ-22, odds ratio = 3.7, p = .015). Conclusions OSAS risk among children and adolescents of Hong Kong with CL/P was 9.5% to 13.6%. Patients at higher risk were those with cleft involving embryonic secondary palate. OSAS risk assessment may be influenced by different aspects of the disease spectrum, and a multimodal approach should be considered for such assessment.

A new goniopholidid from the Upper Jurassic Morrison Formation, USA: novel insight into aquatic adaptation toward modern crocodylians

Goniopholididae is a group of basal neosuchian crocodyliforms closely related to Paralligatoridae and Eusuchia that lived during the Jurassic and Early Cretaceous. Goniopholidids have the long, flat snout and secondary palate of modern crocodylians, the acquisition of which is regarded as a key feature in the early evolution of crocodylian body plan and their aquatic adaptation. Here, we report a new species, Amphicotylus milesi , with the description from the best-preserved specimen to date of Goniopholididae from Wyoming, USA. Its posterior extension of the nasopharyngeal passage (pterygoid secondary palate) and the shortening and dorsal deflection of the ceratobranchial suggest that basal neosuchians could raise their gular valve to separate oral and pharyngeal cavities as in modern crocodylians. The anatomy of Amphicotylus milesi sheds light on the acquisition of this new respiratory system in the crocodyliform evolution and their early aquatic adaptation, leading to modern crocodylians.

Spatiotemporal Expression and Functional Analysis of miRNA-22 in the Developing Secondary Palate

Objective Normal development of the embryonic orofacial region requires precise spatiotemporal coordination between numerous genes. MicroRNAs represent small, single-stranded, non-coding molecules that regulate gene expression. This study examines the role of microRNA-22 (miR-22) in murine orofacial ontogeny. Methods Spatiotemporal and differential expression of miR-22 (mmu-miR-22-3p) within the developing secondary palate was determined by in situ hybridization and quantitative real-time PCR, respectively. Bioinformatic approaches were used to predict potential mRNA targets of miR-22 and analyze their association with cellular functions indispensable for normal orofacial ontogeny. An in vitro palate organ culture system was used to assess the role of miR-22 in secondary palate development. Results There was a progressive increase in miR-22 expression from GD12.5 to GD14.5 in palatal processes. On GD12.5 and GD13.5, miR-22 was expressed in the future oral, nasal, and medial edge epithelia. On GD14.5, miR-22 expression was observed in the residual midline epithelial seam (MES), the nasal epithelium and the mesenchyme, but not in the oral epithelium. Inhibition of miR-22 activity in palate organ cultures resulted in failure of MES removal. Bioinformatic analyses revealed potential mRNA targets of miR-22 that may play significant roles in regulating apoptosis, migration, and/or convergence/extrusion, developmental processes that modulate MES removal during palatogenesis. Conclusions Results from the current study suggest a key role for miR-22 in the removal of the MES during palatogenesis and that miR-22 may represent a potential contributor to the etiology of cleft palate.

A unique form of collective epithelial migration is crucial for tissue fusion in the secondary palate and can overcome loss of epithelial apoptosis

Tissue fusion is an oft-employed process in morphogenesis which often requires the removal of the epithelia intervening multiple distinct primordia to form one continuous structure. In the mammalian secondary palate, a midline epithelial seam (MES) forms between two palatal shelves and must be removed to allow mesenchymal confluence. Abundant apoptosis and cell extrusion in this epithelial seam support their importance in its removal. However, by genetically disrupting the intrinsic apoptotic regulators BAX and BAK within the MES, we find a complete loss of cell death and cell extrusion, but successful removal of the MES, indicating that developmental compensation enables fusion. Novel static and live imaging approaches reveal that the MES is removed through a unique form of collective epithelial cell migration in which epithelial trails and islands stream through the mesenchyme to reach the oral and nasal epithelial surfaces. These epithelial trails and islands begin to express periderm markers while retaining expression of the basal epithelial marker ΔNp63, suggesting their migration to the oral and nasal surface is concomitant with their differentiation to an epithelial intermediate. Live imaging reveals anisotropic actomyosin contractility within epithelial trails that drives their peristaltic movement, and genetic loss of non-muscle myosin IIA-mediated actomyosin contractility results in dispersion of epithelial collectives and dramatic failure of normal MES migration. These findings demonstrate redundancy between cellular mechanisms of morphogenesis and reveal a crucial role for a unique form of collective epithelial migration during tissue fusion.

Prevalence of Dental Anomalies in Patients With Unilateral Cleft Lip and Alveolus Treated With Gingivoperiosteoplasty

Objective: To compare the prevalence of dental malformations and agenesis in patients who received or did not receive gingivoperiosteoplasty (GPP). Design: Retrospective cohort study. Patients: Review of patients born January 1, 2000, to December 31, 2007, with unilateral cleft lip and alveolus, with or without clefting of the secondary palate, who received GPP and/or secondary alveolar bone grafting (ABG). Patients were included if they had clinical images and dental radiographs available at ages 5 to 9 and 10 to 12 years. Ninety-four patients met the inclusion criteria; 46 treated with GPP, and 48 who did not receive GPP. Outcome Measures: Records were assessed for supernumerary, missing, and malformed teeth by a blinded examiner, and prevalence compared between groups using χ2 tests. Results: Cleft side lateral incisors were absent in 54% of GPP patients, compared to 50% in the no-GPP group. Two patients in the GPP group and 1 in the no-GPP group had supernumerary lateral incisors. Most lateral incisors were undersized or peg shaped in both the no-GPP (83.3%) and GPP (71.4%) groups. In the GPP group, 5 (10.9%) patients exhibited central incisor agenesis, and 3 had significant hypoplasia. In the no-GPP group, 4 (8.3%) patients exhibited central incisor agenesis, and 5 (10.5%) significant hypoplasia. These differences were not statistically significant. Conclusions: Gingivoperiosteoplasty was not associated with increased prevalence of dental malformation or agenesis. When performed appropriately, GPP is a safe treatment technique that does not increase the risk of dental anomalies.

Spatio-Temporal Expression Pattern of Ki-67, pRB, MMP-9 and Bax in Human Secondary Palate Development

We analyzed the immunohistochemical expression of Ki-67, pRb, Bax, and MMP-9 during the human secondary palate formation (7th to 12th developmental weeks (DWs). The most significant proliferation was observed in the seventh DW with 32% of Ki-67-positive cells in the epithelium, while loose ectomesenchyme condensations (lec) and loose non-condensing ectomesenchyme (lnc) had only 18 and 11%, respectively (Kruskal–Wallis, p < 0.001), and diminished afterwards. Contrarily, pRb-positive cells were mostly located in the lnc (67%), with significant difference in comparison to epithelium and lec in all investigated periods (Kruskal–Wallis, p < 0.001). Ki-67- and pRb-positive cells co-expressed occasionally in all investigated periods. MMP-9 displayed a strong expression pattern with the highest number of positive cells during the seventh DW in the epithelium, with significant difference in comparison to lec and lnc (Kruskal–Wallis, p < 0.0001). The ninth DW is particularly important for the Bax expression, especially in the epithelium (84%), in comparison to lec (58%) and lnc (47%) (Kruskal–Wallis, p < 0.001). The co-expression of Bax and MMP-9 was seen only in the epithelium during seventh and ninth DWs. Our study indicates the parallel persistence of proliferation (Ki-67, pRb) and remodeling (MMP-9) that enables growth and apoptotic activity (Bax) that enable the removal of the epithelial cells at the fusion point during secondary palate formation.