Fibroblast

The goal of this study is to compare the biological effects of two blood-derived products, standard platelet-rich plasma (PRP) and extracellular vesicle-enriched PRP (EV-enriched PRP), on human gingival (gum) fibroblasts, the cells responsible for gum tissue repair. PRP is a concentrate of platelets prepared from a person's own blood and is used in periodontal and soft tissue regeneration because it releases growth factors. Extracellular vesicles (EVs) are nanometer-sized particles released by platelets that carry proteins and genetic material and may play an important role in tissue healing. No study has yet directly compared standard PRP with an EV-enriched formulation on gingival fibroblasts. The main questions this study aims to answer are: * Does EV-enriched PRP increase gingival fibroblast proliferation more than standard PRP? * Does EV-enriched PRP accelerate gingival fibroblast migration (wound closure) more than standard PRP? * Do the two products differ in their effects on the expression of growth factor and collagen genes in gingival fibroblasts? Six healthy, non-smoking adult volunteers aged 20 to 40 years will each give a single blood sample (two tubes, 18 mL in total) from an arm vein. No treatment will be given to the volunteers. Each volunteer's blood will be processed into both standard PRP and EV-enriched PRP, and both products will be tested in the laboratory on a commercially available human gingival fibroblast cell line.

Keloids are benign fibroproliferative skin disorders characterized by excessive fibroblast activation and extracellular matrix deposition. The molecular mechanisms underlying keloid formation remain incompletely understood. This prospective observational study aims to investigate the biological characteristics of keloid tissue by comparing surgically resected keloid specimens with adjacent normal skin obtained from the same patients. Histological and molecular analyses, including histopathology, polymerase chain reaction (PCR), Western blotting, and related laboratory assays, will be performed to identify signaling pathways and key regulatory factors associated with fibroblast activation. The findings may improve the understanding of keloid pathogenesis and identify potential therapeutic targets for future treatment.

This prospective in vitro study aims to evaluate the effects of two chlorhexidine-based mouthwash formulations on the survival and function of human gingival fibroblasts (hGFs). Gingival fibroblasts obtained from discarded gingival tissue collected during routine dental procedures will be cultured and exposed to different concentrations of a conventional 0.2% chlorhexidine mouthwash and a 0.2% chlorhexidine mouthwash supplemented with N-acetylcysteine (NAC) and hyaluronic acid (HA). Cell viability, apoptosis, migration, and gene expression will be assessed at multiple time points using Trypan Blue exclusion assay, fluorescence-activated cell sorting (FACS), scratch assay, and quantitative real-time PCR. The study is designed to investigate the concentration-dependent effects of chlorhexidine on fibroblast viability and wound-healing-related functions and to determine whether the addition of NAC and HA may improve the biological compatibility of chlorhexidine-based formulations.

Rationale: The diagnosis and pathogenesis of long COVID remains unknown. We have previously shown that \[68Ga\]FAPI Positron Emission Tomography-Computed Tomography (PET/CT) imaging shows potential for diagnosis and molecular understanding of this syndrome. We have previously shown that fibroblast activation protein (FAP) can be imaged in the lung, muscle and nasopharynx of long COVID patients (with dyspnea and fatigue). However, these preliminary data are derived from a selective group of patients with long COVID after critical COVID-19. We aim to explore the generalizability of these findings in patients with long COVID with dyspnea and fatigue, irrespective of the severity of their acute SARS-CoV-2 infection. Primary objective: To assess if pulmonary fibroblast activity, measured by \[68Ga\]FAPI-46 PET/CT, is higher in patients with current long COVID dyspnea and fatigue compared to patients with resolved complaints. Study design: This is a ZonMw funded single centre prospective observational cohort study of long COVID-19 patients with dyspnea and fatigue. Study population: We will recruit 60 adult long COVID patients (aged \>20 years) of which 30 have complaints of dyspnea and fatigue and compare them to 30 patients with resolved complaints and healthy controls. Main study parameters/endpoints: The primary endpoint is FAP expression in the lung measured by \[68Ga\]FAPI-46 PET/CT. Secondary endpoints are the expression of FAP in other tissues (muscle) and the relation between FAP and inflammation and remodelling biomarkers in various biological samples (e.g. serum/nasal epithelium). Study procedures: In a single visit day the following data and samples will be collected: questionnaires, a lung function test, 6-minute walking test, blood samples, nose swabs, \[68Ga\]FAPI PET/CT scan and HRCT scan. When increased \[68Ga\]FAPI uptake is measured in the muscles a muscle biopsy will be performed as well.