Research Spotlight

Tapias Perdigon, H., E. Schneiderman and L. A. Opperman (2019). “Oral health assessment of independent elders in Texas.” Spec Care Dentist 39(5): 515-523.

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BACKGROUND: The oral health status of older adults in North Texas is largely unknown. METHODS: This cross-sectional, pilot study used the Basic Screening Survey for older adults involving a self-administered questionnaire and oral screening examination of 155 adults aged 65 years and older, in four Dallas, TX settings, stratified socioeconomically. Recruitment occurred from July 2012 through March 2014. RESULTS: Participants were between 65 and 90 years of age. The sample was predominantly female (64%), reflecting Texas population diversity with 49.7% White, 34.2% Hispanic, 14.2% Black, and 1.8% others. Missing teeth number (P < .019), functional contacts, untreated decay, root decay (P < .05), tooth mobility, root fragments and need for emergency treatment (P < .021) differed significantly regarding site and ethnicity. Participants at the least affluent sites (two) evidenced significant unmet dental needs and suboptimal access to care. In contrast, those at the most affluent sites (also oldest participants) had good oral health and access to care. CONCLUSIONS: There are profound oral health disparities in urban North Texas based on socioeconomic status. These findings suggest that poor oral health is not inevitable in the elderly, as long as there is access to care. Larger-scale studies are required to broadly address oral health disparities among elderly Texans.

Saiyin, W., L. Li, H. Zhang, Y. Lu and C. Qin (2019). “Inactivation of FAM20B causes cell fate changes in annulus fibrosus of mouse intervertebral disc and disc defects via the alterations of TGF-beta and MAPK signaling pathways.” Biochim Biophys Acta Mol Basis Dis Sep 9;1865(12):165555. [Epub ahead of print].

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Intervertebral disc (IVD) disorder is often caused by the defect of annulus fibrosus (AF), especially that of the outer AF. Studies about the mechanisms governing the development of the outer AF are needed for a better understanding of pathogenesis of IVD defects. Glycosaminoglycans (GAGs) are essential components of extracellular matrix (ECM) in AF. FAM20B is a newly identified xylose kinase that catalyzes the biosynthesis of GAGs. In this study, we created Fam20B conditional knockout (cKO) mice in which FAM20B was inactivated in type I collagen-expressing cells, the main type of cells in the outer AF of IVD. The cKO mice showed severe spine deformity and remarkable IVD defects associated with AF malformation. The AF of cKO mice had a lower level of chondroitin sulfate and heparan sulfate, and the outer AF cells lost their normal fibroblast-like morphology and acquired chondrocyte phenotypes, expressing a higher level of Sox 9 and type II collagen along with a reduced level of type I collagen. The level of phospho-Smad 2 and phospho-Smad 3, and that of scleraxis, a downstream target molecule of canonical TGF-beta signaling pathway were significantly lower in the AF of cKO mice. The AF in cKO mice also manifested altered levels in the molecules associated with the activations of MAPK pathway; the changes included the increase of phospho-P38 and phospho-ERK and a decrease of phospho-JNK. These results indicate that FAM20B plays an essential role in the development of AF by regulating the TGF-beta signaling and MAPK signaling pathways.

McLean-Holden, A. C., J. A. Bishop, H. P. Kessler, L. L. Myers, A. M. Radwan, T. C. Wildey, J. M. Wright and Y. L. Cheng (2019). “Spindle-cell variant of ameloblastic carcinoma: a report of 3 cases and demonstration of epithelial-mesenchymal transition in tumor progression.” Oral Surg Oral Med Oral Pathol Oral Radiol 128(3): e113-e121.

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Ameloblastic carcinoma is a rare odontogenic neoplasm that demonstrates the histologic characteristics of ameloblastoma, accompanied by the cytologic features of malignancy. The spindle-cell variant of ameloblastic carcinoma (SCAC) is exceptionally rare, with a total of 10 cases having been reported in the literature to date. Histologically, a prominent sarcomatoid cell population appears to originate from the epithelial (ameloblastic) component. Like conventional ameloblastic carcinoma, most cases of SCAC occur in individuals older than 40 years of age. Here, 3 additional cases of SCAC are reported, 2 of which occurred in young individuals. Diagnostic criteria to aid in the identification of SCAC are proposed. Finally, histologic and immunohistochemical evidence supporting the occurrence of epithelial-mesenchymal transition in SCAC is presented.

Luo, W., Y. Yi, D. Jing, S. Zhang, Y. Men, W. P. Ge and H. Zhao (2019). “Investigation of Postnatal Craniofacial Bone Development with Tissue Clearing-Based Three-Dimensional Imaging.” Stem Cells Dev 28(19): 1310-1321.

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Traditional two-dimensional histological sections and microcomputed tomography remain to be the major tools for studying craniofacial bones despite the complicated spatial organization of craniofacial organs. Recently, our laboratory developed the Poly(Ethylene Glycol) Associated Solvent System (PEGASOS) tissue clearing method, which can efficiently render hard tissues, including bones and teeth fully transparent without losing endogenous fluorescent signals. Complete tissue transparency enables us to acquire three-dimensional (3D) images of craniofacial bone vasculature, osteogenesis utilizing various labeling strategies, thus to investigate the spatial relationship among different tissues during postnatal craniofacial development. We found out that during the early stage of postnatal development, craniofacial osteogenesis occurs throughout the entire craniofacial bones, including the periosteum, dura, bone marrow, and suture. After 3-4 weeks, craniofacial osteogenesis is gradually restricted to the suture region and remaining bone marrow space. Similarly, craniofacial bone vasculature gradually restricts to the suture region. Osteogenesis is spatially associated with vasculature during the entire postnatal development. Importantly, we demonstrated that in adult calvarial bones, Gli1+ mesenchymal stem cells were also spatially associated with the vasculature. These findings indicate that craniofacial bones share similar osteogenesis mechanism as the long bone despite their distinct osteogenic mechanisms. In addition, the PEGASOS tissue clearing method-based 3D imaging technique is a useful new tool for craniofacial research.

Packer, M. (2019). “Neurohormonal Antagonists Are Preferred to an Implantable Cardioverter-Defibrillator in Preventing Sudden Death in Heart Failure.” JACC Heart Fail 7(10): 902-906.

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One-third to one-half of patients with chronic heart failure and a reduced ejection fraction die suddenly. The terminal event has generally been attributed to a sustained ventricular tachyarrhythmia, whose lethal consequences can be prevented by an implantable cardioverterdefibrillator (ICD). Current guidelines provide a Class I recommendation for ICD placement in patients with heart failure and systolic dysfunction who do not have serious comorbidities, even in patients who have not previously experienced sudden death. Yet the trials that have demonstrated the efficacy of ICDs were largely carried out over 10 to 15 years ago, and during this time, there has been a progressive decline in sudden cardiac death, independent of ICDs, most likely related to advances in heart failure therapeutics that have ameliorated the myocardial substrate that is required for sudden death. Can modern therapy with neurohormonal antagonists pre-empt the need for ICD placement in patients with heart failure? Do randomized controlled trials support their use as first-line agents? (Excerpt from text, p. 902; no abstract available.)