Changes in Plasma Levels of Serotonin and 5-Hydroxyindoleacetic Acid and Population of Serotonin-Secreting Cells in Small and Large Intestine of Wistar Rats in Hypo- and Hyperandrogenemia

Roles of airway and intestinal epithelia in responding to pathogens and maintaining tissue homeostasis

Epithelial cells form a resilient barrier and orchestrate defensive and reparative mechanisms to maintain tissue stability. This review focuses on gut and airway epithelia, which are positioned where the body interfaces with the outside world. We review the many signaling pathways and mechanisms by which epithelial cells at the interface respond to invading pathogens to mount an innate immune response and initiate adaptive immunity and communicate with other cells, including resident microbiota, to heal damaged tissue and maintain homeostasis. We compare and contrast how airway and gut epithelial cells detect pathogens, release antimicrobial effectors, collaborate with macrophages, Tregs and epithelial stem cells to mount an immune response and orchestrate tissue repair. We also describe advanced research models for studying epithelial communication and behaviors during inflammation, tissue injury and disease.

Effects of testosterone replacement on serotonin levels in the prostate and plasma in a murine model of hypogonadism

Benign prostate hyperplasia is a dysfunctional disease with an elevated prevalence. Despite the accepted impact of aging and testosterone (TES) in its pathophysiology, its aetiology remains unknown. Recent studies described that serotonin (5-HT) inhibits benign prostate growth through the modulation of the androgen receptor, in the presence of TES. Accordingly, this work aimed to determine the impact of castration and TES replacement in plasmatic and prostatic 5-HT regulation. C57BL/6 mice were submitted to surgical castration and divided into three groups, continually exposed to either vehicle or different TES doses for 14 days. Plasmatic 5-HT concentration was measured before and after castration, and after TES reintroduction. Finally, total prostatic weight and intra-prostatic 5-HT were determined in the different groups. Our results demonstrate that mice prostate exhibits high 5-HT tissue levels and that intra-prostatic total 5-HT was independent of castration or TES reintroduction, in all studied groups. Also, 5-HT plasmatic concentration significantly increased after castration and then normalized after TES administration. Our findings revealed that mice prostate has a high 5-HT content and that total prostatic 5-HT levels do not depend on androgens' action. On the other hand, castration induced a significant increase in plasmatic 5-HT concentration, raising the hypothesis that androgens might be regulating the production of extra-prostatic 5-HT.

Structural Changes in Large Intestinal Aggregated Lymphoid Follicles in Wistar Rats During Postnatal Ontogeny

Quantitative evaluation of aggregated lymphoid follicles in various compartments of the large intestine was carried out in Wistar rats of different age: newborn (3-4 days), prepubertal (20-30 days), adult (2-3 months), and old (16-18 months). No aggregated lymphoid tissue was detected in the large intestinal mucosa of newborn animals. The cecum of prepubertal, adult, and old animals contained solitary patches with 7-9 follicles. Higher percentage of aggregated lymphoid tissue, associated with colonic mucosa, was explained by enlargement of the lymphoid patch area and of the number of solitary lymphoid follicles during the postnatal ontogenesis. The mean area of a patch in the distal part of the colon in prepubertal, adult, and old animals was 3.2, 2.5, and 2.2 times larger than in the medial part of the intestine, the number of follicles per patch was 2.8, 2.8, and 2.5 times higher, respectively. The differences were significant only for the two younger groups.