VIP and irritable bowel syndrome: In all IBS participants, the densities of VIP and NPY NFs were significantly negatively correlated with IBS‐SSS (r = −0.453, p = 0.039 and r = −0.587, p = 0.005, respectively) and TH and NPY NFs with the IBS‐SSS abdominal pain component subscore (r = −0.434, p = 0.044 and r = −0.601, p = 0.04) (Figure 3A–D; Table S5).