NHE3 is widely used as a functional marker of differentiated IECs (38), and examination of ileal NHE3 revealed reduced fluorescent intensity of NHE3+ staining at the apical part of IECs in AF mice compared with PF mice, whereas the strongest NHE3+ staining were observed in AF+IL-22 mice (Figure 8B). This evidence concerns the gene IL22 and atrial fibrillation.