Upregulation of Vanilloid Receptor-1 in Functional Dyspepsia With or Without Helicobacter pylori Infection.

The etiological basis of functional dyspepsia (FD) is incompletely understood. The aim of this study was to evaluate the involvement of nociceptor-related genes and Helicobacter pylori (HP) in the pathogenesis of FD. The expression of nociceptor-related genes was measured in gastric cell lines that were co-cultured with HP. FD patients (n = 117) and controls (n = 55) were enrolled from a tertiary hospital gastroenterology clinic. Expression of the genes nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), and transient receptor potential cation channel subfamily V member 1 (TRPV1) in the gastric mucosa were detected by reverse transcription polymerase chain reaction (RT-PCR), and immunohistochemical staining of TRPV1 was analyzed. These measurements were repeated after 1 year. TRPV1, GDNF, and NGF expression was elevated in gastric cell lines co-cultured with HP. TRPV1 immunostaining was stronger in HP-positive than HP-negative subjects. The FD group showed higher expression levels of TRPV1, GDNF, and NGF and increased TRPV1 immunostaining compared with those of the control group (all P < 0.05). Among 61 subjects who were followed up at 1 year, controls with successful HP eradication and patients whose symptoms had improved both showed significant reductions in the expression of TRPV1 and NGF (all P < 0.05) compared with controls without HP eradication and patients whose symptoms had not improved, respectively. The expression of NGF, GDNF, and TRPV1 may be associated with the pathogenesis of FD. Since HP infection may induce the increased expression of these genes, anti-HP therapy could be beneficial for HP-positive patients with FD.