Incidence and risk factors of nocturnal penetrations and aspirations in patients with obstructive sleep apnea during drug-induced sedation endoscopy.

Obstructive sleep apnea has been linked to an increased risk of pneumonia, possibly due to higher rates of nighttime aspirations. Few studies have directly investigated such aspirations in individuals with sleep apnea. This retrospective study included 142 adult patients with obstructive sleep apnea who underwent drug-induced sedation endoscopy between 2017 and 2020. The incidence of penetrations and aspirations during the procedure was assessed, along with potential associated factors. The results showed that 28.1% of the patients experienced penetrations, 48.5% had aspirations, and 23.2% had neither. Male gender and epiglottic collapse were significantly associated with both penetrations and aspirations, while oropharyngeal collapse was more common in those without these events. This study highlights a high rate of aspirations during the procedure in individuals with sleep apnea, with epiglottic collapse and male gender identified as potential risk factors. These findings underscore the need for further research to understand the mechanisms of nighttime aspirations in sleep apnea and to develop targeted strategies to reduce pneumonia risk in this population.

Discrete limbal epithelial stem cell populations mediate corneal homeostasis and wound healing.

The accessibility and transparency of the cornea permit robust stem cell labeling and in vivo cell fate mapping. Limbal epithelial stem cells (LSCs) that renew the cornea are traditionally viewed as rare, slow-cycling cells that follow deterministic rules dictating their self-renewal or differentiation. Here, we combined single-cell RNA sequencing and advanced quantitative lineage tracing for in-depth analysis of the murine limbal epithelium. These analysis revealed the co-existence of two LSC populations localized in separate and well-defined sub-compartments, termed the "outer" and "inner" limbus. The primitive population of quiescent outer LSCs participates in wound healing and boundary formation, and these cells are regulated by T cells, which serve as a niche. In contrast, the inner peri-corneal limbus hosts active LSCs that maintain corneal epithelial homeostasis. Quantitative analyses suggest that LSC populations are abundant, following stochastic rules and neutral drift dynamics. Together these results demonstrate that discrete LSC populations mediate corneal homeostasis and regeneration.

Spatial correlations constrain cellular lifespan and pattern formation in corneal epithelium homeostasis.

Homeostasis in adult tissues relies on the replication dynamics of stem cells, their progenitors and the spatial balance between them. This spatial and kinetic coordination is crucial to the successful maintenance of tissue size and its replenishment with new cells. However, our understanding of the role of cellular replicative lifespan and spatial correlation between cells in shaping tissue integrity is still lacking. We developed a mathematical model for the stochastic spatial dynamics that underlie the rejuvenation of corneal epithelium. Our model takes into account different spatial correlations between cell replication and cell removal. We derive the tradeoffs between replicative lifespan, spatial correlation length, and tissue rejuvenation dynamics. We determine the conditions that allow homeostasis and are consistent with biological timescales, pattern formation, and mutants phenotypes. Our results can be extended to any cellular system in which spatial homeostasis is maintained through cell replication.