Exosomes as emerging mediators and therapeutic vehicles in painful diabetic neuropathy: From pathophysiology to clinical translation

Table 7 Summary of methodological considerations

Methodological considerations: Isolation method	Advantages	Limitations	Recommendation	Synthetic insight: PDN-specific consideration
Differential ultracentrifugation	Reference standard; widely used	Co-pellets aggregates, lipoproteins, other vesicle subtypes; operator-dependent	Requires standardized protocols (rotor type, g-force, time)	Most widely used in PDN biomarker studies to date, enabling cross-study comparison; however, co-pelleting of lipoproteins is a particular concern in diabetic patients, who frequently have dyslipidemia that elevates plasma lipoprotein levels
Size exclusion chromatography	Superior purity; maintains vesicle integrity	Reduced yield; requires specialized equipment	Suitable for protein biomarker studies	Preferred for NfL and protein biomarker studies in PDN given superior removal of lipoprotein contamination; recommended when exosomal protein rather than miRNA cargo is the primary analytical target
Polymer-based precipitation	Simple; scalable	Substantial non-vesicular contamination (protein aggregates, lipoproteins)	Caution advised for protein cargo analysis	Particularly unreliable in diabetic plasma due to elevated lipoprotein and acute-phase protein levels; not recommended for PDN biomarker discovery or validation studies
Immunoaffinity capture	High specificity for vesicle subpopulations	Requires validated antibodies; limited by incomplete knowledge of surface proteomes	Preferred for cell-type-specific exosome analysis	Critical enabling technology for PDN specificity: L1CAM capture for neuronal and MOG capture for Schwann cell-derived exosomes directly addresses the neural-signal dilution problem in plasma and is the recommended approach for PDN biomarker validation cohorts

NfL: Neurofilament light chain; L1CAM: L1 cell adhesion molecule; MOG: Myelin oligodendrocyte glycoprotein; PDN: Painful diabetic neuropathy; miRNAs: MicroRNAs.