Fig 2: Analysis of the number of NAAA-ir cells per area (µm2) in the lamina propria of control group compared to acute UC patients and after 5-ASA and corticosteroid treatment (quiescent group).A–F: Representative high-magnification photomicrographs showing NAAA immunostaining in the lamina propria. G: Acute UC at disease onset was associated with a significant decrease in the number of NAAA-ir cells in the infiltrate of the lamina propria. The number of NAAA-ir cells was increased to control levels after treatment (5-ASA and corticoids). Mann-Whitney U and Wilcoxon tests (N = 15–22): ***P<0.001 versus control group; ## P<0.01 versus acute UC group.

Fig 3: Relative quantification of PPARα (A), PPARγ (B), NAAA (C), iNOS (D), NAPE-PLD (E) and FAAH (F) gene expression in the colonic mucosa of active UC patients compared to human healthy colonic tissue (control).Absolute values were normalized with regard to the housekeeping gene SP1. Active UC at disease onset showed lower PPARα, PPARγ and NAAA gene expression, but higher iNOS and FAAH gene expression compared to control. No change was detected for NAPE-PLD gene expression. Student t test (N = 8): *P<0.05, **P<0.01 versus control group.

Fig 4: RT-PCR (A–D), Western blot (E–H) and immunohistochemical analyses (I–T) showing the presence and distribution of PPARa, NAAA, NAPE-PLD and FAAH in the normal human colonic tissue.Gene expressions of PPARa, NAAA, NAPE-PLD and FAAH were detected in both mucosa (epithelium and lamina propria) and submucosa (smooth muscle and plexi) layers (A–D), and confirmed by high-magnification photomicrographs of their protein expression by immunohistochemistry (I–T). Western blots of protein extracts from human colonic tissue showed prominent immunoreactive bands of the expected size for PPARa (52 kDa), NAAA (31 kDa), NAPE-PLD (46 kDa) and FAAH (62 kDa). Positions of molecular markers (MW) are indicated at the left (E–H). Abbreviations: CSM, circular smooth muscle; E, epithelium; LSM, longitudinal smooth muscle; LP, lamina propria; M, mucosa; MP, myenteric plexus.

Fig 5: Representative high-magnification photomicrographs showing double immunofluorescence for NAAA, CD19, CD3 and CD14 in order to characterize the immune cells in the mucosa infiltrate of UC patients.NAAA immunofluorescence was observed in CD19+ B lymphocytes (A–C), CD3+ T lymphocytes (D–F) and CD14+ macrophages (G–I).