Although mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are as effective as MSCs in the suppression of allergic airway inflammation, few studies have evaluated the immunomodulatory capacity of MSC-derived EVs in patients with asthma. Thus, we assessed the effects of adipose stem cell (ASC)-derived EVs on cytokine expression and regulatory T cells (Tregs) in peripheral blood mononuclear cells (PBMCs) of asthmatic patients. PBMCs (1 × 10⁶ cells/mL) were isolated from asthmatic patient and healthy controls and co-cultured with 1 μg/mL of ASC-derived EVs. Th (T helper) 1-, Th2-, and Treg-related cytokine expression, fluorescence-activated cell sorting analysis of CD4⁺CD25⁺FOXP3⁺ T cells, and co-stimulatory molecules were analyzed before and after ASC-derived EV treatment. The expression levels of IL-4 and costimulatory molecules such as CD83 and CD86 were significantly higher in PBMCs of asthmatic patients than in control PBMCs. However, ASC-derived EV treatment significantly decreased the levels of interleukin (IL)-4 and co-stimulatory molecules such as CD83 and CD86 in the phytohemagglutinin (PHA)-stimulated PBMC of asthmatic patients. Furthermore, ASC-derived EVs remarkably increased the transforming growth factor-β (TGF-β) levels and expression of Tregs in the PBMC of asthmatic patients. ASC-derived EVs induce Treg expansion and have immunomodulatory effects by downregulating IL-4 and upregulating TGF-β in PBMCs of asthmatic patients.

Although adipose stem cell (ASC)-derived extracellular vesicles (EVs) are as effective as ASCs in the suppression of Th2 cell-mediated eosinophilic inflammation, the role of identified pulmonary genes has not been well documented. Thus, we assessed the immunomodulatory effects of paraoxonase-1 (PON1) on allergic airway inflammation in a mouse model of asthma. Five-week-old female C57BL/6 mice were sensitized to ovalbumin (OVA) by intraperitoneal injection and challenged intranasally with OVA. To evaluate the effect of PON1 on allergic airway inflammation, the intranasal and intraperitoneal injections of recombinant mouse serum PON1 (5 μg/50 μL) were performed before the OVA challenge. We evaluated airway hyperresponsiveness (AHR), total inflammatory cells, and eosinophils in the bronchoalveolar lavage fluid (BALF), lung histology, serum immunoglobulin (Ig), cytokine profiles of BALF and lung draining lymph nodes (LLNs), the expression of interleukin (IL)-25 and transforming growth factor (TGF)-β in mouse lung epithelial cell (MLE-12 cell), and dendritic cell (DC) differentiation. The intraperitoneal and intranasal administration of PON1 significantly decreased AHR, total inflammatory cells and eosinophils in BALF, eosinophilic airway inflammation, serum total, and OVA-specific IgE. PON1 treatment, which marked reduced IL-4, IL-5, and IL-13 in the BALF and LLN but significantly increased interferon-γ and TGF-β. Furthermore, PON1 treatment significantly decreased the expression of IL-25 and increased TGF-β in MLE-12 cells. The expressions of CD40, CD80, and CD86 in immature DCs were significantly increased by PON1 treatment. The administration of PON1 ameliorated allergic airway inflammation and improved AHR through the downregulation of IL-4, IL-5, and IL-13 and upregulation of TGF-β in asthmatic mice. Furthermore, PON1 treatment decreased Th2-mediated inflammation induced by Aspergillus protease antigen by decreasing IL-25 and increasing TGF-β.

Plasmacytoma is a rare hematolymphoid malignancy. The three types of plasmacytoma, according to clinical features and morphological characteristics, include solitary bone plasmacytoma, extramedullary plasmacytoma (EMP), and multiple myeloma (MM). Although EMP of the head and neck region accounts for approximately 3% of all plasma cell tumors, the involvement of both paranasal sinuses is extremely rare. Herein, we describe a rare case of EMP involving both maxillary sinuses in a 73-year-old male patient who had achieved complete remission from MM following chemotherapy 2 years ago. The EMP was treated successfully with radiotherapy.

Particulate matter (PM) is a major environmental pollutant implicated in various respiratory diseases. However, its impact on the upper respiratory tract, particularly the nasal and paranasal sinus mucosa, remains poorly understood. This study aimed to investigate the acute inflammatory effects of PM exposure on the sinonasal mucosa and evaluate the natural recovery process in a controlled rat model. Ten-week-old male Sprague Dawley rats were exposed to incense-derived PM in a custom-designed exposure chamber for 2 h daily for seven consecutive days. Rats were sacrificed at 3, 7, and 14 days post-exposure. Histopathologic changes were assessed using hematoxylin and eosin and Alcian blue staining, and mucosal gene expression of inflammatory cytokines including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and IL-5 and MUC5AC was quantified using real-time reverse transcription polymerase chain reaction. PM exposure induced significant histological alterations, including epithelial thickening, inflammatory cell infiltration, and goblet cell hyperplasia, which peaked at 7 days post-exposure. Expression levels of TNF-α and IFN-γ were significantly elevated at 7 days compared to controls. The sinonasal mucosa in the 14-day post-exposure groups exhibited a remarkable decrease in goblet cell numbers, and IL-1β and TNF-α expression. Short-term exposure to high concentrations of PM resulted in acute inflammatory changes in the sinonasal mucosa of rats, including epithelial thickening and goblet cell hyperplasia. These changes were partially resolved after exposure ended, indicating that PM-induced sinonasal inflammation may be at least partially reversible.

Olfactory impairment is one of the most common diseases of the sense organs, and it is closely related to quality life. Although the molecular mechanism of olfaction was recently brought to light, the pathophysiology and effective treatments for olfactory dysfunction still remain challenging. Olfactory impairment can be caused by the degeneration of olfactory receptor neurons in the nose and also by the degeneration of the olfactory bulb of the olfactory cortex. Several studies have shown that stem cells promote the regeneration of the olfactory neuroepithelium after permanent damage in anosmic mice. Transplanted adipose stem cells differentiated into olfactory receptor neurons and endothelial cells. Recently, cell-free approaches using stem cell-derived secretome and extracellular vesicles (EVs) have emerged as a safer, more controllable alternative. These vesicles contain biologically active cargo such as neurotrophins, cytokines, and microRNAs that promote neurogenesis and modulate inflammation. Although direct application in anosmia models remains limited, findings from related neural injury models suggest that secretome- and EV-based therapies may achieve comparable regenerative efficacy to stem cell transplantation. This review summarizes current evidence on the regenerative capacity of stem cells and their secretome or EVs as therapeutic strategies for olfactory epithelium regeneration.