Single-cell transcriptome analyses reveal signals to activate dormant neural stem cells.

The scarcity of tissue-specific stem cells and the complexity of their surrounding environment have made molecular characterization of these cells particularly challenging. Through single-cell transcriptome and weighted gene co-expression network analysis (WGCNA), we uncovered molecular properties of CD133(+)/GFAP(-) ependymal (E) cells in the adult mouse forebrain neurogenic zone. Surprisingly, prominent hub genes of the gene network unique to ependymal CD133(+)/GFAP(-) quiescent cells were enriched for immune-responsive genes, as well as genes encoding receptors for angiogenic factors. Administration of vascular endothelial growth factor (VEGF) activated CD133(+) ependymal neural stem cells (NSCs), lining not only the lateral but also the fourth ventricles and, together with basic fibroblast growth factor (bFGF), elicited subsequent neural lineage differentiation and migration. This study revealed the existence of dormant ependymal NSCs throughout the ventricular surface of the CNS, as well as signals abundant after injury for their activation.

Condylar Position is Maintained in Maxillomandibular Advancement Surgery Utilizing Custom Cutting Guides and Plates.

PURPOSE: The objective of this study is to compare virtual surgical planned (VSP) and postoperative condylar positioning outcomes in patients who underwent maxillomandibular advancement surgery with custom mandibular cutting guides and osteosynthesis plates to establish reliability and effectiveness using these forms of technology. METHODS: An ambispective case series was performed by obtaining preoperative and postoperative computed tomography (CT) scans of obstructive sleep apnea patients who underwent maxillomandibular advancement surgery with VSP and custom printed mandibular cutting guides and plates at the San Francisco Veterans Affairs Healthcare System from February 2019 to October 2021. The primary predictor variables were the use of custom guides and plates compared to VSP over the course of a year. The outcome variable was the maintained condylar position, defined as the mean differences between the VSP and postoperative positioning. The comparison group was the preoperative VSP position. Covariates were planned surgical movements, age, and gender. Measurements were taken bilaterally in sagittal CT sections measuring the condylar positioning within the posterior space, superior space, and anterior space of the glenoid fossae. Similarly, coronal CT section measurements were taken to measure the condylar positioning within the coronal lateral space, coronal central space, and coronal medial space. A Wilcoxon signed rank test was used. RESULTS: This study included 6 male participants (n = 6) aged 32 to 57 years (mean 46.5). The median differences for the posterior space, superior space, and anterior space planned versus postoperative position were 0.25 (0.40), 0.40 (0.35), and 0.40 (0.55) mm, respectively. The median differences for the coronal lateral space, coronal central space, and coronal medial space planned versus postoperative position were 0.30 (0.30), 0.78 (0.70), and 0.40 (0.30) mm, respectively. There was no statistically significant difference in the planned and postoperative condylar position (Wilcoxon signed rank test, P > .5). A qualitative analysis showed little to no displacement or rotation of the condyle in the virtually planned and postoperative condylar positions. CONCLUSIONS: Qualitative and quantitative comparisons of the preoperative virtual surgical planned and the postoperative condylar position with the use of custom-printed mandibular cutting guides and plates support the null hypothesis that there is no difference between planned and postoperative positioning.