Sera with anti‐enteric neuronal antibodies from patients with irritable bowel syndrome promote apoptosis in myenteric neurons of guinea pigs and human SH‐Sy5Y cells

• Published in: Neurogastroenterology and motility Vol. 30; no. 12; pp. e13457 - n/a
• Main Authors: Fan, Wenjuan, Fei, Guijun, Li, Xiaoqing, Wang, Xiyu, Hu, Chaojun, Xin, Haiwei, Sun, Xiaohong, Li, Yongzhe, Wood, Jackie D, Fang, Xiucai
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.12.2018
• Subjects: Antibodies; Apoptosis; autoantibodies; Autoimmune diseases; Caspase; Constipation; Degeneration; Enteric nervous system; Fetal calf serum; Flow cytometry; Fluorescence; Immunofluorescence; Immunoglobulins; Inflammatory bowel diseases; Irritable bowel syndrome; Myenteric plexus; Neurons; Neuropathy; Small intestine; apoptosis; enteric nervous system; irritable bowel syndrome; autoantibodies
• ISSN: 1350-1925; 1365-2982; 1365-2982
• DOI: 10.1111/nmo.13457

Background Sera anti‐enteric neuronal antibodies (AENA), neuronal inflammation, and degeneration in myenteric plexus in patients with irritable bowel syndrome (IBS) were reported. Effects of sera AENA in patients with IBS are unclear. Methods Patients with IBS met Rome III criteria were enrolled. Controls included healthy subjects (HS) and patients with slow transit functional constipation, inflammatory bowel disease, chronic intestinal pseudo‐obstruction, and autoimmune diseases. Indirect immunofluorescence was used to detect AENA. Anti‐enteric neuronal antibodies intensities were termed as “1” = weak fluorescence (mild positive); “2” = moderate fluorescence (moderate positive); “3” = very high fluorescence (intensive positive). Intensities of ≥1 were defined as positive and ≥2 were defined as obvious positive. Cultured myenteric neurons of small intestine from guinea pigs and human SH‐Sy5Y cells were incubated with fetal bovine serum (FBS), HS sera, or IBS sera with or without AENA. Indirect immunofluorescence with anti‐PGP9.5/DAPI/anti‐active caspase‐3 or TUNEL, Western blot, and flow cytometry were used to detect apoptosis. Key Results Overall, 293 patients with IBS were enrolled (41.7 ± 11.5 years). AENA‐positive and obvious positive rates in IBS were higher than HS (76.8% vs 33%; 43.7% vs 7%; all P < 0.001). Myenteric neurons incubated with AENA moderate or intensive positive IBS sera showed higher rates of anti‐active caspase‐3 and TUNEL‐positive cells than HS or FBS (20% ± 7.3% and 35% ± 13.3% vs 4.3% ± 1.5% and 0.9% ± 0.4%, respectively; 6.2% ± 2.0% and 10.2% ± 4.6% vs 1.3% ± 1.9% and 0.5%±0.5%, respectively; all P < 0.05). Human SH‐Sy5Y cells incubated with AENA moderate or intensive positive IBS sera showed increased cleaved caspase‐3 and Bax expression and decreased Bcl‐2 expression. Flow cytometry showed apoptosis rates of these two groups were higher than that of AENA mild positive, negative, HS, and FBS (7.6%±0.8% and 10.7%±1.3% vs 5.0%±0.8%, 3.8%±0.3%, 3.4%±0.2% and, 2.8%±0.2%, P < 0.05). Conclusions and Inferences The AENA obvious positive rate in patients with IBS was higher than HS, and sera with higher levels of AENA promoted neuronal apoptosis. AENA‐mediated neuropathy might exist in a subset of patients with IBS. The pathophysiology of myenteric neuronal degeneration in patients with irritable bowel syndrome (IBS) is unclear. The anti‐enteric neuronal antibody (AENA) obvious positive rate in IBS was higher than in healthy subjects and was higher than patients with slow transit functional constipation and inflammatory bowel disease after eliminating the influence of antinuclear antibodies. Sera with obvious positive AENA from IBS patients promoted neuronal apoptosis in cultured myenteric neurons of guinea pigs and human SH‐Sy5Y cells. The apoptosis‐promoting effects of AENA might explain the autoimmune pathophysiological changes for a subset of patients with IBS.