Exploring serum amino acid signatures as potential biomarkers in Hashimoto's thyroiditis patients

Hashimoto's thyroiditis (HT) is an autoimmune disease caused by the immune system attacking healthy tissues. However, the exact pathogenesis of HT remains unclear. Metabolomic analysis was performed to obtain information about the possible pathogenic mechanisms and diagnostic biomarkers of HT. The amino acid profile was analyzed using an LC–MS/MS method using serum samples obtained from 30 patients diagnosed with ultrasonographic imaging and laboratory markers (thyroid stimulating hormone) free thyroxine and thyroid peroxidase) and 30 healthy individuals. There were statistically significant changes in 27 amino acids out of 32 amino acids analyzed (p < 0.05). Based on the receiver operating characteristic curve analysis, the six amino acid (1-methylhistidine, cystine, norvaline, histidine, glutamic acid and leucine) biomarkers showed high sensitivity, specificity (area under the curve > 0.98), positive likelihood ratio and low negative likelihood ratio. Also, according to pathway analysis, degradation of phenylalanine, tyrosine and tryptophan biosynthesis was the highest metabolic pathway according to the impact value (p < 0.001 and impact value = 1.0). We provide serum amino acid profiles of patients with Hashimoto's thyroiditis and identify five potential biomarkers for early diagnosis by clinicians.