Nocturnal stem cell mobilization in patients with obstructive sleep apnoea: a pilot study

Chronic Intermittent Hypoxia-Induced Neural Injury: Pathophysiology, Neurodegenerative Implications, and Therapeutic Insights

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a sleep-related respiratory disorder that poses a global threat to human health. Chronic intermittent hypoxia (CIH) is its main pathological feature. With the advancements in medical research, the study of CIH-induced neural injury has gained increasing attention. Studies have shown that CIH can lead to or aggravate neuroinflammation and apoptosis by increasing blood-brain barrier (BBB) permeability, promoting oxidative stress, activating glial cells, and triggering multiple signaling pathways, ultimately resulting in neural injury. These processes contribute to the development of Alzheimer's disease, Parkinson's disease, and stroke. This review aims to summarize the progress in CIH-induced neural injury and explore various underlying mechanisms, with the goal of providing new insights for the development of therapeutic interventions targeting CIH-related neural damage.

Mouth opening/breathing is common in sleep apnea and linked to more nocturnal water loss

OBJECTIVES

Mouth opening/breathing during sleep is common in patients with obstructive sleep apnea (OSA), which is probably associated with more water loss and higher risk for nocturnal ischemic heart attack. This study aimed to evaluate nocturnal changes in hematocrit/hemoglobin levels and estimated plasma volume loss in OSA patients and its relation to their OSA severity and mouth open/breathing.

METHODS

Sixty OSA patients and fifteen healthy controls were enrolled and underwent overnight polysomnography. Mouth status was evaluated via an infrared camera and nasal/mouth airflow. Hematocrit and hemoglobin levels in peripheral venous blood were measured before and after sleep to estimate the change of plasma volume.

RESULTS

Compared to controls, OSA patients had a greater nocturnal increase in hematocrit (1.35% vs. 1.0%, p=0.013), hemoglobin (0.50% vs. 0.30%, p=0.002) and more estimated water loss (5.5% vs 3.7% of plasma volume, p<0.013). The extent of increase was correlated to apnea-hypopnea index_the marker of OSA severity (Spearman's ρ=0.332, p=0.004; ρ=0.367, p=0.001 for hematocrit, hemoglobin, respectively), which remained significant after serial multivariate adjustment. OSA patients had more sleep time with mouth open (96.7% vs 26.7% of total sleep time, p<0.001) and time with complete mouth breathing (14.1% vs 2.7%, p<0.001). The extent of mouth breathing was correlated to apnea-hypopnea index (ρ=0.487, p<0.001), nocturnal increase in hematocrit/hemoglobin levels (ρ=0.236, p=0.042; ρ=0.304, p=0.008, respectively) and estimated plasma volume loss (ρ=0.262, p=0.023).

CONCLUSIONS

OSA patients had a greater increase in hematocrit/hemoglobin levels after sleep, which is probably linked to more water loss and more sleep time with mouth open/breathing.

Stem/progenitor cells and obstructive sleep apnea syndrome - new insights for clinical applications

Obstructive sleep apnea syndrome (OSAS) is a widespread disorder, characterized by recurrent upper airway obstruction during sleep, mostly as a result of complete or partial pharyngeal obstruction. Due to the occurrence of frequent and regular hypoxic events, patients with OSAS are at increased risk of cardiovascular disease, stroke, metabolic disorders, occupational errors, motor vehicle accidents and even death. Thus, OSAS has severe consequences and represents a significant economic burden. However, some of the consequences, as well as their costs can be reduced with appropriate detection and treatment. In this context, the recent advances that were made in stem cell biology knowledge and stem cell - based technologies hold a great promise for various medical conditions, including respiratory diseases. However, the investigation of the role of stem cells in OSAS is still recent and rather limited, requiring further studies, both in animal models and humans. The goal of this review is to summarize the current state of knowledge regarding both lung resident as well as circulating stem/progenitor cells and discuss existing controversies in the field in order to identify future research directions for clinical applications in OSAS. Also, the paper highlights the requisite for inter-institutional, multi-disciplinary research collaborations in order to achieve breakthrough results in the field.