title: Gender-related differences in irritable bowel syndrome: potential mechanisms of sex hormones.
abstract: According to epidemiological studies, twice as many women as men are affected by irritable bowel syndrome (IBS) in western countries, suggesting a role for sex hormones in IBS pathophysiology. Despite growing evidence about the implications of sex hormones in IBS symptom modulation, data on mechanisms by which they influence disease development are sparse. This review aims to determine the state of knowledge about the role of sex hormones in sensorimotor dysfunctions and to address the possible interplay of sex hormones with common risk factors associated with IBS. The scientific bibliography was searched using the following keywords: irritable bowel syndrome, sex, gender, ovarian hormone, estradiol, progesterone, testosterone, symptoms, pain, sensitivity, motility, permeability, stress, immune system, brain activity, spinal, supraspinal, imaging. Ovarian hormones variations along the menstrual cycle affect sensorimotor gastrointestinal function in both healthy and IBS populations. They can modulate pain processing by interacting with neuromodulator systems and the emotional system responsible for visceral pain perception. These hormones can also modulate the susceptibility to stress, which is a pivotal factor in IBS occurrence and symptom severity. For instance, estrogen-dependent hyper-responsiveness to stress can promote immune activation or impairments of gut barrier function. In conclusion, whereas it is important to keep in mind that ovarian hormones cannot be considered as a causal factor of IBS, they arguably modulate IBS onset and symptomatology. However, our understanding of the underlying mechanisms remains limited and studies assessing the link between IBS symptoms and ovarian hormone levels are needed to improve our knowledge of the disease evolution with regard to gender. Further studies assessing the role of male hormones are also needed to understand fully the role of sex hormones in IBS. Finally, investigation of brain-gut interactions is critical to decipher how stress, ovarian hormones, and female brain processing of pain can translate into gut dysfunctions.
authors.affiliation: Mathieu Meleine, Department of Inflammation, Nutrition and Gut-Brain Axis Dysfunction, Inserm Unit 1073, Faculté de Médecine et Pharmacie, Université de Rouen, 76183 Rouen, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Meleine
authors.affiliation: Mathieu Meleine, Department of Inflammation, Nutrition and Gut-Brain Axis Dysfunction, Inserm Unit 1073, Faculté de Médecine et Pharmacie, Université de Rouen, 76183 Rouen, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Matricon
mesh_terms: D000818:Animals; D005260:Female; D005769:Gastrointestinal Motility; D041981:Gastrointestinal Tract / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D006801:Humans; D006930:Hyperalgesia / Q000378:metabolism / Q000503:physiopathology; D043183:Irritable Bowel Syndrome / Q000453:epidemiology / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008954:Models, Biological; D010053:Ovary / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D017288:Pain Threshold; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D012737:Sex Factors; D059265:Visceral Pain / Q000378:metabolism / Q000503:physiopathology
chemical_list: D012739:Gonadal Steroid Hormones
keywords: Gender; Gut; Immune activation; Irritable bowel syndrome; Neurosensitization; Pathophysiology; Permeabilization; Sensori-motricity; Sex hormones; Stress