Background/Objectives: As bioactive extracellular vesicles, exosomes participate in cellular communication and disease mechanisms, yet their structural complexity continues to challenge standard analytical methodologies. This review summarizes published studies reporting exosome concentrations in human plasma, serum, and platelet-rich plasma from healthy individuals and highlights methodological differences. Methods: A comprehensive PubMed search (1986–31 August 2025) was performed using terms related to exosomes and their quantification, excluding cancer- and disease-related studies. Eligible articles reported exosome concentrations in plasma, serum, or platelet-rich plasma using particle-counting techniques such as nanoparticle tracking analysis, flow cytometry, or tunable resistive pulse sensing. Results: Twenty-two articles, including 167 healthy donors, met the inclusion criteria. The following mean concentration ranges were reported: plasma (n = 18), ranged from 4.50 × 10⁸ to 6.70 × 10¹¹ particles/mL with differences by quantification method; serum (n = 10), from 5.30 × 10⁸ to 2.13 × 10¹¹ particles/mL; non-activated platelet-rich plasma (n = 1), 7.52 × 10⁹ particles/mL; activated platelet-rich plasma (n = 3), 4.87 × 10¹⁰ to 7.16 × 10¹⁰ particles/mL; and preconditioned platelet-rich plasma with photothermal biomodulation (n = 2), 2.53 × 10¹¹ to 2.99 × 10¹¹ particles/mL. Conclusions: Isolation and quantification methods exhibit high variability, which strongly influences the overall quantity and quality of the exosomes obtained. Characteristics, including cargo composition, purity, and exosome integrity, must be considered when developing validated methods. Furthermore, emerging evidence suggests that PTBM preconditioning can increase exosome release from cells. In summary, rigorous standardization of protocols is essential to advance the scientific understanding and the clinical potential of exosome-based therapies.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) belongs to the EGF family of growth factors which are ligands of the ErbB receptors. Studies in animals suggest the role of HB-EGF in several pathogenic processes such as atherosclerosis and heart hypertrophy. Here, we set up an assay to measure HB-EGF in human serum. Our ELISA determined serum HB-EGF in the range of 0.03–3 nM. It did not cross-react with EGF or with transforming growth factor-α. The mean serum HB-EGF was 0.26 nM (confidence interval: 0.13–0.39) in women and 0.28 nM (confidence interval: 0.09–0.47) in men. In a cohort of 121 healthy volunteers, we identified nine individuals with high serum HB-EGF (above 0.47 nM). These individuals had higher left ventricle mass (determined by Colour Doppler echocardiography) and greater total and low density lipoprotein cholesterol than control. On the basis of our results, we propose that increased serum HB-EGF is associated with heart hypertrophy and elevated blood cholesterol.

Conventional endoscopic sonography has allowed precise diagnostics without disturbances, and miniprobes can be easily introduced through the biopsy channel of the endoscope. Miniprobe endoscopic sonography has many benefits compared with conventional endoscopic sonography. Although there are well‐known indications for miniprobe endoscopic sonography in endoscopic digestive tract assessment, there is still a need for this method to be widely spread among physicians and commonly used by most endoscopists. The aim of this series was to describe a multicenter retrospective experience with 1451 procedures using miniprobes, presenting examples and the applicability and usefulness of this technology in the daily activities of an endoscopy department.