Metabolomics strategies are widely used to examine
obesity and
type 2 diabetes (T2D). Patients with
obesity (n = 31) or T2D (n = 26) and sex- and age-matched controls (n = 28) were recruited, and serum and tear samples were collected. The concentration of 23
amino acids and 10
biogenic amines in serum and tear samples was analyzed. Statistical analysis and Pearson correlation analysis along with network analysis were carried out. Compared to controls, changes in the level of 6 analytes in the obese group and of 10 analytes in the T2D group were statistically significant. For
obesity, the energy generation, while for T2D, the involvement of NO synthesis and its relation to
insulin signaling and
inflammation, were characteristic. We found that BCAA and
glutamine metabolism,
urea cycle, and beta-oxidation make up crucial parts of the metabolic changes in T2D. According to our data, the retromer-mediated retrograde transport, the
ethanolamine metabolism, and, consequently, the
endocannabinoid signaling and
phospholipid metabolism were characteristic of both conditions and can be relevant pathways to understanding and treating
insulin resistance. By providing potential therapeutic targets and new starting points for mechanistic studies, our results emphasize the importance of complex data analysis procedures to better understand the pathomechanism of
obesity and diabetes.