Saiki S, et al. - With spermidine and spermine experimentally augmenting longevity through autophagy induction, researchers assessed each polyamine metabolite to see if they could act as age-related, diagnostic, and severity-related biomarkers for Parkinson's disease (PD). Spermine was the most robust inducer of autophagy among polyamine metabolites, particularly in SH-SY5Y cells. Compared to controls, no significant genetic differences have been identified in five genes encoding enzymes connected with spermine/spermidine metabolism. Findings suggested that spermine synthesis and N1,N8-diacetylspermidine may be helpful biomarkers related to diagnosis and severity for PD, respectively.