Previous Ingestion of Lactococcus lactis by Ethanol-Treated Mice Preserves Antigen Presentation Hierarchy in the Gut and Oral Tolerance Susceptibility

Gut Barrier Dysfunction and Type 2 Immunity: Implications for Compulsive Behavior

To date, much of the focus of gut-brain axis research has been on gut microbiota regulation of anxiety and stress-related behaviors. Much less attention has been directed to potential connections between gut microbiota and compulsive behavior. Here, we discuss a potential link between gut barrier dysfunction and compulsive behavior that is mediated through "type 2" rather than "type 1" inflammation. We examine connections between compulsive behavior and type 2 inflammation in Tourette syndrome, obsessive-compulsive disorder, autism, addiction, and post-traumatic stress disorder. Next, we discuss potential connections between gut barrier dysfunction, type 2 inflammation, and compulsive behavior. We posit a potential mechanism whereby gut barrier dysfunction-associated type 2 inflammation may drive compulsive behavior through histamine regulation of dopamine neurotransmission. Finally, we discuss the possibility of exploiting the greater accessibility of the gut relative to the brain in identifying targets to treat compulsive behavior disorders.

Lactococcus lactis Administration Modulates IgE and IL-4 Production and Promotes Enterobacteria Growth in the Gut from Ethanol-Intake Mice

BACKGROUND

It is well known that alcohol can trigger inflammatory effects in the gastrointestinal tract (GIT) interfering with mucosal homeostasis.

OBJECTIVE

This study evaluated the effectiveness of Lactococcus lactis treatment in controlling the increase in molecular biomarkers related to allergic inflammation, and the effect on the diversity and abundance of the Enterobacteriaceae family in the GIT after high-dose acute administration of ethanol.

METHODS

Mice received ethanol or saline solution by gavage for four consecutive days, and 24 h after the last administration the animals were given L. lactis or M17 broth orally ad libitum for two consecutive days. The animals were subsequently sacrificed and dissected.

RESULTS

L. lactis treatment was able to restore basal levels of secretory immunoglobulin A in the gastric mucosa, serum total immunoglobulin E, interleukin (IL)-4 production in gastric and intestinal tissues, and IL-10 levels in gastric tissue. L. lactis treatment encouraged the diversification of the Enterobacteriaceae population, particularly the commensal species, in the GIT.

CONCLUSION

This research opens a field of studies regarding the modulatory effect of L. lactis on immunological and microbial changes induced after alcohol intake.

Modulating effects of the probiotic Lactococcus lactis on the hepatic fibrotic process induced by CCl4 in Wistar rats

Hepatic cirrhosis is a chronic disease that affects one fifth of the World's population and is the third leading cause of death in Mexico. Attempts have been made to develop treatments for this hepatic cirrhosis, which include manipulating the intestinal microbiota and thus decreasing the early inflammatory response. The microbiota is reportedly altered in patients with cirrhosis. Due to its immunomodulatory properties and its ability to survive in the gastrointestinal tract, Lactococcus lactis (L. lactis) has been used as a therapeutic measure in inflammatory disorders of the colon. The objective of the present study was to evaluate the efficacy of the L. lactis probiotic NZ9000 in preventing tetrachloromethane (CCl₄)-induced experimental hepatic fibrosis. The following 4 groups were included in the experimental stage (n=5): i) Control group; ii) L. lactis group; iii) CCl₄ group; and iv) L. lactis-CCl₄ group. For the first 2 weeks, L. lactis was orally administered to the L. lactis and L. lactis-CCl₄ groups; CCl₄ was then peritoneally administered to the lactis-CCl₄ group for a further 4 weeks (in addition to the probiotic), while the L. lactis group received the probiotic only. For the CCl₄ group, CCl₄ was administered for 4 weeks. The experimental groups were all compared with the control group and the L. lactis + CCl₄ group. Tissue samples were analyzed histologically and biochemically, and the gene expression levels of interleukin (IL)-1, IL-10 and forkhead box protein P3 (FoxP3) were determined. L. lactis decreased hepatic cirrhosis by preventing steatosis and fibrosis, and by reducing the levels of AST and ALT. Subchronic CCl₄ injury induced upregulation of the IL-1β gene in the liver, which was decreased by L. lactis. It was also found that the group treated with L. lactis showed increased expression of Foxp3 in the liver and IL-10 in the gut. These results suggested that oral administration of L. lactis may be a potential probiotic to prevent or protect against CCl₄-induced liver injury.

High-Fat Diet and Alcohol Intake Promotes Inflammation and Impairs Skin Wound Healing in Wistar Rats

The wound-healing process is complex and remains a challenging process under the influence of several factors, including eating habits. As improper diets may lead to disorders such as dyslipidemia, insulin resistance, and chronic inflammation, potentially affecting the tissue ability to heal, we decided to investigate the effect of a high-fat diet and alcohol intake on the inflammatory process and skin wound healing in Wistar rats. Male rats (n = 30) were individually housed in cages with food and water ad libitum (registration number 213/2014). After anesthesia, at day 40, three circular wounds (12 mm diameter) were made on the back of each animal, which were then randomly assorted into five treatment groups: C1 (control 1)-water via gavage and standard chow diet; C2 (control 2)-water (no gavage) and standard chow diet; AL (alcohol)-water (no gavage) and alcohol (40%) via gavage and standard chow diet; HF (high fat)-water (no gavage) and high-fat diet (50%); and HF + AL (alcohol/high fat)-water (no gavage), alcohol (40%) via gavage, and high-fat diet. Animals were treated for 61 days. Every seven days, the area and the rate of wound contraction were evaluated. Tissue samples were removed for histopathological analysis and biochemical analyses. Our results showed that wound contraction was not complete in the HF + AL rats. Two specific indices of wound-healing impairment (total cell number and levels of the inflammatory cytokine TGF-β) were increased in the HF + AL rats. We also observed decreased type I and III collagen fibers in the HF, AL, and HF + AL groups and increased oxidative stress markers in the same groups. We suggest that a high-fat diet combined with alcohol intake contributed to delayed skin wound healing through increase of the inflammatory phase and promoting oxidative stress, which may have led to morphological alterations and impaired matrix remodeling.