Natural compulsive‐like behaviour in the deer mouse (Peromyscus maniculatus bairdii) is associated with altered gut microbiota composition

Obsessive–compulsive disorder (OCD) is a psychiatric illness that significantly impacts affected patients and available treatments yield suboptimal therapeutic response. Recently, the role of the gut–brain axis (GBA) in psychiatric illness has emerged as a potential target for therapeutic exploration. However, studies concerning the role of the GBA in OCD are limited. To investigate whether a naturally occurring obsessive–compulsive‐like phenotype in a rodent model, that is large nest building in deer mice, is associated with perturbations in the gut microbiome, we investigated and characterised the gut microbiota in specific‐pathogen‐free bred and housed large (LNB) and normal (NNB) nest‐building deer mice of both sexes (n = 11 per group, including three males and eight females). Following baseline characterisation of nest‐building behaviour, a single faecal sample was collected from each animal and the gut microbiota analysed. Our results reveal the overall microbial composition of LNB animals to be distinctly different compared to controls (PERMANOVA p < .05). While no genera were found to be significantly differentially abundant after correcting for multiple comparisons, the normal phenotype showed a higher loading of Prevotella and Anaeroplasma, while the OC phenotype demonstrated a higher loading of Desulfovermiculus, Aestuariispira, Peptococcus and Holdemanella (cut‐off threshold for loading at 0.2 in either the first or second component of the PCA). These findings not only provide proof‐of‐concept for continued investigation of the GBA in OCD, but also highlight a potential underlying aetiological association between alterations in the gut microbiota and the natural development of obsessive–compulsive‐like behaviours.     

Age‐related changes in inguinal region anatomy from 0 to 19 years of age

Knowledge of the age‐related changes in inguinal region anatomy is essential in pediatric urological and abdominal surgery, yet little is published. This study aimed to determine the position of inguinal region structures and growth of the surrounding pelvis and inguinal ligament in subjects from 0 to 19 years of age. Anonymized contrast‐enhanced CT DICOM datasets of 103 patients (63 male: 40 female) aged from 0 to 19 years had left and right sides analyzed by three independent observers. Exclusion criteria were applied. Growth of the pelvis and inguinal ligament were determined using fixed bony reference points. The position of the deep inguinal ring and femoral vasculature were determined as ratio of inguinal ligament length, measured from the anterior superior iliac spine. Growth of the pelvis in vertical and horizontal dimensions and of the inguinal ligament followed a positive polynomial relationship with increasing age, with no observed increase in growth rate during puberty. From 0 to 19 years, the deep inguinal ring moved superolaterally with respect to the inguinal ligament (from 0.74 to 0.60 of the distance along the inguinal ligament) and the femoral artery and vein moved medially (from 0.50 to 0.58, and 0.61 to 0.65 of the distance along the inguinal ligament, respectively). The position of the femoral artery, vein, and deep inguinal ring followed a logarithmic relationship with age. No significant left:right side or male:female differences were observed. From 0 to 19 years of age the femoral vasculature and deep inguinal ring change position as the pelvis grows around them. Clin. Anat. 32:794–802, 2019. © 2019 Wiley Periodicals, Inc.