12-months prospective Pentraxin-3 and metabolomic evaluation in multiple sclerosis patients treated with glatiramer acetate

Background: Pentraxin-3 (PTX-3) is involved in acute immunological responses and it is a pro-inflammatory protein and a novel biomarker of inflammatory diseases. It is demonstrated that PTX-3 is higher in cerebrospinal fluid (CSF) of aggressive Multiple Sclerosis (MS). Metabolomics, the identification of small endogenous molecules, offers a molecular profile of MS. Glatiramer acetate (GA) is a widely used treatment for (MS) but its mechanism of action is not completely defined. The aim of our study is to analyze PTX-3 and metabolomic profile in MS patients compared to controls and to investigate the effect of GA on PXT-3 and metabolic molecules during treatment in responder and not responder MS patients. Methods: 28 unrelated MS patients and 27 age-and sex-matched controls were recruited. In serum, PTX-3 levels were measured by ELISA and Metabolomic panel was evaluated trough Nuclear Magnetic Resonance (NMR). According to clinical practice patients started GA treatment; PTX-3 and metabolomic identification were performed before and during treatment. Responders to treatment were identified if no evidence of instrumental, clinical relapses and disability progression (NEDA) occurred during follow up. Results: Serum PTX-3 levels were higher in MS patients compared to matched controls (7,85 ± 2,19 vs 6,20 ± 1,63 ng/ml) (p = 0,03); metabolomic evaluation shows higher levels of lactate and lower levels of valine, tyrosine and tryptophan in MS patients compared to controls. During therapy, PTX-3 levels have been reduced statistically significant (p = 0,001) at six months and one year of treatment. After one year, of the twenty patients that completed the study, 55% were considered fully responders to treatment; in these patients the mean reduction of PTX-3 at one year was higher respect to not responders (−3,82 ± 1,24 ng/ml vs −2,32 ± 1,03 ng/ml p = 0,02) and we observed a higher reduction of lactate, tyrosine and hypoxanthine and an increase of hydroxyproline and ADP as well as of three oxidative phosphorylation markers, citrulline, ornithine and tryptophan approaching the metabolic profile of healthy subjects. Discussion and conclusions: We demonstrated a metabolomic imbalance with mitochondrial dysfunction detected by higher levels of lactate and lower levels of tryptophan, tyrosine and valine in MS patients compared to healthy controls. The reduction of PTX-3 levels and the restoring of mitochondrial function, reducing oxidative stress by GA, allows to identify responder patients. Further and larger studies are needed to understand the predictive role of PTX-3 and metabolomic pattern in the identification of responder patients to GA