Adipokines as Possible Players in Inflammatory Bowel Disease: Electrophysiological Evaluation of Their Role in Causing Functional Gastrointestinal Alterations in Murine Tissue

Inflammatory bowel disease (IBD) is a clinical condition of the gastrointestinal tract that has significant incidence in childhood. Major symptoms include abdominal pain, dyspepsia, delayed gastric emptying, anorexia, diarrhea and weight loss. IBD etiopathogenesis is multifactorial, with a proven involvement of cytokines. In this regard, cytokines like resistin and adiponectin produced by adipose tissue play a crucial role in inflammation. Particularly, resistin seems related to IBD severity and is considered a promising marker of disease occurrence and progression. Unraveling its mechanism of action and downstream effectors is mandatory when designing novel therapies. This preclinical study aims to further elucidate the action of resistin in causing functional gastrointestinal alterations, comparing it with the well-defined effect of adiponectin. To this end, we carried out electrophysiological analysis on murine gastric fundus. We found that resistin, similarly to adiponectin, increases smooth muscle cell (SMC) capacitance, indicative of cell surface remodeling, which is consistent with relaxation. However, contrary to adiponectin, resistin unalters membrane potential and inward Ca2+ entry and scarcely affects outward current, suggesting its inefficacy in markedly modifying electrical phenomena on the SMC membrane. This outcome, supporting the role of resistin in gastrointestinal distention, as observed in IBD, rules out a strikingly direct effect on SMCs.