Severe obesity is a major risk for
chronic kidney disease (CKD). Early detection and careful monitoring of renal function are critical for the prevention of CKD during
obesity, since biopsies are not performed in patients with CKD and diagnosis is dependent on the assessment of clinical parameters. To explore whether distinct
lipid and metabolic signatures in
obesity may signify early stages of pathogenesis toward CKD, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-high resolution accurate mass-mass spectrometry (GC-HRAM-MS) analyses were performed in the serum and the urine of severely obese patients with and without CKD. Moreover, the impact of
bariatric surgery (BS) in
lipid and metabolic signature was also studied, through LC-MS and GC-HRAM-MS analyses in the serum and urine of patients with
severe obesity and CKD before and after undergoing BS. Regarding patients with
severe obesity and CKD compared to severely obese patients without CKD, serum lipidome analysis revealed significant differences in
lipid signature. Furthermore, serum metabolomics profile revealed significant changes in specific
amino acids, with
isoleucine and
tyrosine, increased in CKD patients compared with patients without CKD. LC-MS and GC-HRAM-MS analysis in serum of patients with
severe obesity and CKD after BS showed downregulation of levels of
triglycerides (TGs) and
diglycerides (DGs) as well as a decrease in
branched-chain amino acid (BCAA),
lysine,
threonine,
proline, and
serine. In addition, BS removed most of the correlations in CKD patients against biochemical parameters related to kidney dysfunction. Concerning urine analysis,
hippuric acid,
valine and
glutamine were significantly decreased in urine from CKD patients after surgery. Interestingly,
bariatric surgery did not restore all the
lipid species, some of them decreased, hence drawing attention to them as potential targets for early diagnosis or therapeutic intervention. Results obtained in this study would justify the use of comprehensive mass spectrometry-based lipidomics to measure other
lipids aside from conventional
lipid profiles and to validate possible early markers of risk of CKD in patients with
severe obesity.