Pulmonary neuroendocrine cells at the airway neuroimmune interface: a bibliometric analysis

Pulmonary neuroendocrine cells (PNECs) and neuroepithelial bodies (NEBs) are specialized airway epithelial structures involved in environmental sensing, neuroendocrine secretion, epithelial regulation, and inflammatory responses. However, the bibliometric structure, thematic evolution, and emerging neuroimmune orientation of PNEC/NEB research at the airway neuroimmune interface have not been quantitatively characterized.

Publications from 1990 to 2025 were retrieved from the Web of Science Core Collection (WoSCC) and Scopus using a predefined search strategy. After database merging, deduplication, and bibliographic standardization, 595 English-language articles and reviews were included. Scopus was predefined as the primary source of document-level citation counts, with WoSCC counts used only for publications not indexed in Scopus; database-specific and maximum-count approaches were evaluated in sensitivity analyses. Bibliometrix, VOSviewer, and CiteSpace were used to analyze publication trends, geographic and institutional contributions, author collaboration, journal and reference co-citation, keyword clustering, temporal evolution, and citation bursts. Representative experimental studies were used to contextualize the major bibliometric themes.

The included publications accumulated 25,399 citations under the predefined primary citation-count rule, with research activity increasing after 2019 and reaching a maximum of 28 publications in 2024. Citation-based rankings were robust across database-specific and alternative counting approaches, and the top 10 publications were unchanged under the maximum-count sensitivity analysis. The United States contributed the largest number of publications, while the University of Toronto and University of Antwerp were among the leading institutions. Representative experimental studies were used to contextualize these bibliometric patterns by describing mediator-specific interactions among PNECs and epithelial, neural, and immune compartments. The thematic structure comprised pulmonary neuroendocrine signaling, airway chemoreception, neuropeptide processing, and lung development, among others. Temporal and burst analyses indicated that early research focused on NEB morphology, bombesin/GRP, oxygen sensing, and airway chemoreception, whereas later studies increasingly addressed PNEC-specific biology, epithelial plasticity, hyperplasia, allergic inflammation, and neuroimmune signaling.

PNEC research has expanded from morphological and chemosensory characterization toward an integrated framework involving epithelial plasticity, airway functional responses, and neuroimmune communication. Human-relevant models, spatially resolved analyses, and cell- and mediator-specific experiments will be essential for defining the context-dependent functions and therapeutic relevance of PNECs.