Preoperative Serum Transient Receptor Potential Ankyrin 1 (TRPA1) Levels in Class III Obesity: A Prospective Controlled Observational Study.

Transient Receptor Potential Ankyrin 1 (TRPA1) is a membrane cation channel activated by oxidative stress products that are chronically elevated in class III obesity. Although tissue-level TRPA1 biology is increasingly well described, the biological meaning of circulating immunoreactive TRPA1 remains poorly established. This single-centre, prospective, controlled observational study compared preoperative serum TRPA1 between adults with class III obesity scheduled for laparoscopic sleeve gastrectomy and contemporaneous controls, and explored metabolic and inflammatory correlates of the circulating signal. Serum TRPA1 was quantified by enzyme-linked immunosorbent assay (ELISA) in 42 consecutive surgical candidates and 36 controls. The primary analysis used continuous (log-transformed) TRPA1 with age- and sex-adjusted logistic regression; ROC-derived dichotomisation was retained only as an exploratory analysis. Serum TRPA1 did not differ between groups (median 309.8 vs. 340.5 pg/mL; Mann-Whitney U, p = 0.323; Hodges-Lehmann median difference [obesity - control] -30.8 pg/mL, bootstrap 95% CI -227.43 to 43.02). After adjustment for age and sex, continuous log-TRPA1 was not independently associated with obesity status (OR per log-unit 0.88, 95% CI 0.46-1.69; p = 0.699), and discrimination was poor (AUC 0.435; 95% CI 0.305-0.562). Established inflammatory and metabolic markers differed between groups, but serum TRPA1 did not track them. In this cohort, preoperative serum TRPA1 did not distinguish class III obesity from controls. The negative circulating finding should be interpreted as lack of evidence for a large between-group difference in ELISA-measured serum TRPA1-and as a potential translational disconnect from tissue TRPA1 biology-rather than as the definitive exclusion of any tissue-level role for the channel.