TRPV1 and gastroesophageal reflux disease: Reported daily heartburn severity scores, as assessed by the validated RDQ, did not show a correlation with the mucosal barrier parameters (TEER (r: −0.20, p = 0.31)), permeability (r: 0.01, p = 1.0), or TRPV1 gene transcription (r: 0.23, p = 0.27).