Abstract
BACKGROUND: Aquaporins (AQPs) are integral membrane proteins that facilitate water transport across biological membranes. While their role is well-characterized in various tissues, their function in the oral cavity remains poorly understood. Saliva is an easily accessible, non-invasive biofluid that contains stable extracellular RNA and can reflect both systemic and local physiological or pathological processes, making it a promising source for RNA analyses. This study investigates AQP mRNA levels in human saliva. METHODS: Saliva samples were collected from patients of a dental practice and analyzed using quantitative PCR to detect AQP levels. An in silico analysis of AQPs in cells of the oral cavity were performed. Baseline data of the patients were recorded. RESULTS: Our findings demonstrate the presence of multiple AQP subtypes in human saliva. AQP5 was the most abundant, followed by AQP9 and AQP1. The levels of several AQPs showed intercorrelation, whereas AQP3 appeared to be independently regulated and did not correlate with the other AQPs. CONCLUSIONS: This study demonstrates that differential AQP mRNA levels can be detected in human saliva. These findings suggest that salivary AQP mRNA may serve as surrogate markers for altered AQP levels in cells of the oral cavity. In the future, such patterns of AQP levels could potentially be used to identify or monitor pathological conditions affecting the oral mucosa or salivary glands. Further studies are required to validate this approach and to understand its diagnostic relevance.