Does expression of substance-P in normal appendices confirm the neuroimmune appendicitis or disprove the negative appendectomy?

Abstract

Introduction: Detection of specific histological alteration in appendices was carried out using immunohistochemical technique involved using antibodies against a neuropeptide substance-P (s-P). Methods: Fifty patients aged 3-45 years (21 male and 29 female) admitted to Azadi Teaching Hospital, Kerkuk province, Iraq with clear clinical symptoms of appendicitis. Results: Significant differences (p≤0.034) was detected at age 11-15 and 16-30 years of patients with clinical suspected appendicitis (CSA) in most patients while right iliac fossa pain (RIFP), vomiting and nausea were predominate clinical symptoms yet non-specific signs of appendicitis. Only 82% appendices appeared inflamed and 18% were normal (without inflammation), were considered as experimental cases. The intensity and location of the s-P expression was classified as either no expression (negative s-P), weak (+) or strong (++). In experimental cases it was strongly expressed in nerve plexus than in acute inflammation of epithelium and muscularis layers while in lamina propria the expression was almost the same between the two groups. The normal appendices with symptoms were found without inflammation yet s-P expression was detectable. Conclusion: Therefore, the stronger expression of s-P in normal appendices may confirm the concept of neuroimmune appendicitis which disproves the negative term of "appendectomy". Further immunehistochemical studies are on to explore specific histological alteration associated with the pains using other antibodies i.e. vasoactive intestinal polypeptide (VIP) and GAP-43.