Short-term positive effects of a mandibular advancement device in a selected phenotype of patients with moderate obstructive sleep apnea: a prospective study

STUDY OBJECTIVES

To evaluate (determinants of) treatment success of mandibular advancement device application in a selected phenotype of patients with obstructive sleep apnea (OSA).

METHODS

Ninety nonobese patients with moderate OSA (obstructive apnea-hypopnea index [OAHI] ≥ 15 and < 30 events/h) without comorbidities were prospectively included. Polysomnography was performed at baseline and with a mandibular advancement device. A drug-induced sleep endoscopy with jaw thrust was performed in 83%.

RESULTS

OAHI reduction ≥ 50% was observed in 73%, OAHI reduction ≥ 50% with OAHI < 10 events/h in 70%, and complete OSA resolution (OAHI < 5 events/h) in 40%. Patients with nonpositional OSA showed a significantly higher rate of complete OSA resolution: Posttest probability increased to 67%. In patients with total disappearance of collapse at velum level and at all levels during drug-induced sleep endoscopy with jaw thrust, the drop in OAHI was impressive with an infinitively high positive likelihood ratio. However, the proportion of patients having nonpositional OSA or the drug-induced sleep endoscopy characteristics as described above was < 20%. The change in snoring disturbance based on a visual analog scale was 76% (interquartile range 40-89%, P < .001) and a statistically significant amelioration in Epworth Sleepiness Scale (especially in somnolent subjects) was observed. High adherence was reported.

CONCLUSIONS

In this predefined OSA phenotype, a mandibular advancement device was effective in reduction of OAHI and in amelioration of symptoms. Stratification by nonpositional OSA and findings on drug-induced sleep endoscopy with jaw thrust increased treatment success defined as reduction in OAHI. However, the clinical relevance can be questioned because only a small number of patients demonstrated these characteristics.

CITATION

Buyse B, Nguyen PAH, Leemans J, et al. Short-term positive effects of a mandibular advancement device in a selected phenotype of patients with moderate obstructive sleep apnea: a prospective study. J Clin Sleep Med. 2023;19(1):5-16.

Microarray screening for target genes of the proto-oncogene PLAG1

PLAG1 is a proto-oncogene whose ectopic expression can trigger the development of pleomorphic adenomas of the salivary glands and of lipoblastomas. As PLAG1 is a transcription factor, able to activate transcription through the binding to the consensus sequence GRGGC(N)(6-8)GGG, its ectopic expression presumably results in the deregulation of target genes, leading to uncontrolled cell proliferation. The identification of PLAG1 target genes is therefore a crucial step in understanding the molecular mechanisms involved in PLAG1-induced tumorigenesis. To this end, we analysed the changes in gene expression caused by the conditional induction of PLAG1 expression in fetal kidney 293 cell lines. Using oligonucleotide microarray analyses of about 12 000 genes, we consistently identified 47 genes induced and 12 genes repressed by PLAG1. One of the largest classes identified as upregulated PLAG1 targets consists of growth factors such as the insulin-like growth factor II and the cytokine-like factor 1. The in silico search for PLAG1 consensus sequences in the promoter of the upregulated genes reveals that a large proportion of them harbor several copies of the PLAG1-binding motif, suggesting that they represent direct PLAG1 targets. Our approach was complemented by the comparison of the expression profiles of pleomorphic adenomas induced by PLAG1 versus normal salivary glands. Concordance between these two sets of experiments pinpointed 12 genes that were significantly and consistently upregulated in pleomorphic adenomas and in PLAG1-expressing cells, identifying them as putative PLAG1 targets in these tumors.