High-fat enteral nutrition reduces intestinal mucosal barrier damage after peritoneal air exposure

High-fat diet promotes the effect of fructo-oligosaccharides on the colonic luminal environment, including alkaline phosphatase activity in rats

We recently reported that fermentable nondigestible carbohydrates such as oligosaccharides, commonly increase colonic alkaline phosphatase (ALP) activity and the gene expression of Alpi-1, coding for rat intestinal alkaline phosphatase-I isozyme in rats and that the effect of oligosaccharides on colonic ALP activity is affected by the quality of dietary fats. We hypothesized that the amount of dietary fat would modulate the effect of oligosaccharides on colonic ALP and luminal environment in rats. In experiment 1, male Sprague-Dawley rats were fed a low-fat (LF, 5% lard) or high-fat (HF, 30% lard) diet with or without 4% fructo-oligosaccharides (FOS). In experiment 2, they were fed a 2.5%, 7%, 20%, or 40% fat (lard) diet with 4% FOS for 2 weeks. Dietary FOS in the HF diet (HF-FOS) significantly increased ALP activity in the colon and cecal digesta and colonic expression of Alpi-1, but not in the LF diet with FOS groups (LF-FOS). In comparison to the LF-FOS group, the increases in fecal mucins, Lactobacillus ratio, as well as cecal n-butyrate, and the decrease in fecal Clostridium coccoides, were more pronounced in the HF-FOS group. Compared with the 2.5% or 7% fat + FOS diet, the 20% fat + FOS diet significantly increased colonic ALP activity, Alpi-1 expression, and fecal mucins. These factors did not differ significantly between 20% and 40% fat + FOS diets. To exert the maximum effect of FOS on the colonic luminal environment, including ALP activity in rats, significantly more fat may be required than that contained present a LF diet.

Astaxanthin, a carotenoid antioxidant, pretreatment alleviates cognitive deficits in aircraft noised mice by attenuating inflammatory and oxidative damage to the gut, heart and hippocampus

BACKGROUND

We first explore whether aircraft noise (AN) induces cognitive deficit via inducing oxidative damage in multiple vital organs including intestines, hearts and hippocampus tissues. Second, we explore whether the AN-induced cognitive deficits and inflammatory and oxidative damage to multiple organs can be alleviated by Astaxanthin (AX) pretreatment.

METHODS

Cognitive deficits were induced by subjecting the mice to AN 2 h daily for 7 consecutive days. An intragastrical dose of AX emulsifier (at the dose of daily feed intake [6 g] of a mouse three times weekly) was given to mice for consecutive 8 weeks prior to the start of AN. Cognitive functions were evaluated by using passive avoidance apparatus, Y-maze, Morris water maze and novel recognition test. Intestinal permeability was determined by measuring the intestinal clearance of fluorescein-isothiocyante. Evans Blue extravasation assay was used to measure the permeability of blood-brain-barrier. Inflammatory and oxidative damage to multiple organs were determined by measuring several pro-inflammatory cytokines and oxidative stress indicators in intestines; hearts and hippocampus.

RESULTS

Mice treated with AN displayed exacerbated stress reactions, cognitive deficits, gut barrier hyperpermeability, increased upload of lipopolysaccharide translocation, systemic pro-inflammatory cytokines overproduction, blood-brain-barrier hyperpermeability, hippocampal neuroinflammation and increased levels of oxidative stress indicators in intestine, heart and hippocampus. All of the above-mentioned disorders caused by AN were significantly (P < 0.05) reversed by AX.

CONCLUSIONS

Our data indicate that AX pretreatment alleviates cognitive deficits in aircraft noised mice by attenuating inflammatory and oxidative damage to intestines, hearts and hippocampal tissues.

Expression of TLR2 and TLR5 in distal ileum of mice with obstructive jaundice and their role in intestinal mucosal injury

INTRODUCTION

The aim was to investigate the expression of TLR2 and TLR5 in the distal ileum of mice with obstructive jaundice (OJ) and their role in intestinal mucosal injury.

MATERIAL AND METHODS

A total of 100 male C57BL/6J mice were randomly assigned to two groups: (I) sham operation (SH); (II) bile duct ligation (BDL). The mice were respectively sacrificed before operation and on the 1^st, 3^rd, 5^th and 7^th days after operation to collect specimens. Various indicators were detected by PCR, immunohistochemistry and other methods.

RESULTS

TLR2 was increased gradually with the extension of OJ time in the BDL group (p < 0.05). However, the changes in the expression of TLR5 were not obvious at different time points. The amount of Bifidobacteria and Lactobacillus showed downward trends in intestinal tract of the BDL group. Furthermore, the amount of Escherichia coli was increased in intestinal tract of the BDL group. The pathological score of intestinal mucosa and the expression of NF-κB increased gradually in the BDL group with the extension of OJ time. There were positive correlations between the pathological score of intestinal mucosa and expressions of TLR2(r = 0.767, p < 0.05) and NF-κB (r = 0.817, p < 0.05) in BDL group. NF-κB expression was positively correlated with TLR2 expression(r = 0.706, p < 0.05).

CONCLUSIONS

Disturbance of intestinal flora caused by OJ could increase the expression of NF-κB via up-regulating the expression of TLR2 to activate the downstream signaling pathway, thus aggravated the injury of intestinal mucosa.

Aircraft noise, like heat stress, causes cognitive impairments via similar mechanisms in male mice

To our knowledge, little evidence is available about effects of aircraft noise (AN), a non-chemical stressor, on cognitive function. Again, it is unknown whether or not the heat stress (HS)-induced cognitive deficits can be exacerbated by AN. The adult male mice were assigned to four groups: group 1 mice exposed to non-HS (24-26 °C 2 h daily for 4 consecutive days) and white noise (WN) (2 h daily for 4 consecutive days), group 2 mice exposed to WN and HS (32-34 °C 2 h daily for 4 consecutive days), group 3 mice exposed to AN and non-HS (2 h daily for 4 consecutive days) and group 4 mice exposed to AN and HS (2 h daily for consecutive 4 days). Cognitive function were determined by passive avoidance, Y-maze, Morris water maze, and novel object recognition tests. Gut barrier and blood-brain-barrier (BBB) permeability, upload of lipopolysaccharide (LPS) translocation, systemic and central inflammation, and stress reactions were examined. Heat stressed mice displayed both increased stress reactions and learning and memory loss. Heat stress also caused gut barrier hyperpermeability, increased upload of LPS translocation, systemic inflammation, BBB disruption and hippocampal neuroinflammation. Aircraft noise stressed mice did not display systemic inflammation but caused gut barrier hyperpermeability, increased upload of LPS translocation, increased stress reactions, BBB disruption, hippocampal neuroinflammation and cognitive deficits. Aircraft noise exposure further exacerbated the heat stress-induced cognitive deficits and its complications. Our data suggest that AN, like HS, causes cognitive impairments via similar mechanisms in male mice.

Selective brain cooling achieves peripheral organs protection in hemorrhagic shock resuscitation via preserving the integrity of the brain-gut axis

Background: Although whole-body cooling has been reported to improve the ischemic/reperfusion injury in hemorrhagic shock (HS) resuscitation, it is limited by its adverse reactions following therapeutic hypothermia. HS affects the experimental and clinical bowel disorders via activation of the brain-gut axis. It is unknown whether selective brain cooling achieves beneficial effects in HS resuscitation via preserving the integrity of the brain-gut axis. Methods: Male Sprague-Dawley rats were bled to hypovolemic HS and resuscitated with blood transfusion followed by retrograde jugular vein flush (RJVF) with 4 °C or 36 °C normal saline. The mean arterial blood pressure, cerebral blood flow, and brain and core temperature were measured. The integrity of intestinal tight junction proteins and permeability, blood pro-inflammatory cytokines, and multiple organs damage score were determined. Results: Following blood transfusion resuscitation, HS rats displayed gut barrier disruption, increased blood levels of pro-inflammatory cytokines, and peripheral vital organ injuries. Intrajugular-based infusion cooled the brain robustly with a minimal effect on body temperature. This brain cooling significantly reduced the HS resuscitation-induced gut disruption, systemic inflammation, and peripheral vital organ injuries in rats. Conclusion: Resuscitation with selective brain cooling achieves peripheral vital organs protection in hemorrhagic shock resuscitation via preserving the integrity of the brain-gut axis.

Beta-1 blocker reduces inflammation and preserves intestinal barrier function after open abdominal surgery

BACKGROUND

Open abdominal surgery is frequently related to excessive inflammation and a compromised intestinal barrier, leading to poor clinical outcomes. The administration of beta-1 blocker has been shown to effectively reduce inflammation and preserve intestinal barrier function in patients with sepsis, shock, or other critical illnesses. The underlying mechanism of these effects may be associated with the autonomic nervous system's activation via cholecystokinin receptors. This study aimed to investigate the effect of beta-1 blocker on systemic and local inflammatory responses and the intestinal barrier function in the context of open abdominal surgery.

METHODS

A rat model of open abdominal surgery was induced through peritoneal air exposure for 3 hours and treated via gavage with the beta-1 blocker, metoprolol, or saline. Cholecystokinin-receptor antagonists were administered before the metoprolol treatment. Peritoneal lavage fluid, serum, and tissues were collected 24 hours after surgery to determine systemic and local inflammation and intestinal integrity.

RESULTS

The intervention with metoprolol significantly reduced serum tumor necrosis factor-alpha and interleukin-6 (P < .05) and peritoneal interleukin-6 (P < .01) compared with those of animals treated with saline. The intestinal myeloperoxidase indicating the influx of neutrophils was also significantly prevented by the administration of metoprolol (P < .05). Above all, this intervention resulted in a significant decrease in serum D-lactate and intestinal fatty acid-binding protein, intestinal permeability, bacterial translocation, and Chiu's score for intestinal mucosa injury (P < .05). However, the anti-inflammatory and intestinal integrity protective effects of metoprolol were prevented by the blockage of cholecystokinin receptors (P < .05).

CONCLUSION

Our data indicate that beta-1 blocker reduces systemic and local inflammatory responses and preserves intestinal barrier function after open abdominal surgery through a mechanism that depends on cholecystokinin receptors. Clinically, these findings imply that perioperative intervention with a beta-1 blocker may be an effective new therapy to enhance recovery after open abdominal surgery.

Enteral Nutrition in Patients with Inflammatory Bowel Disease. Systematic Review, Meta-Analysis, and Meta-Regression

Inflammatory bowel disease (IBD) is a chronic disease mediated by the immune system and is characterized by inflammation of the gastrointestinal tract. One of the possible treatments for this pathology is a change in the type of diet, of which enteral nutrition (EN) is one. This study is to understand how the use of EN can affect the adult population diagnosed with IBD. We conducted a systematic review, meta-analysis, and a meta-regression. On the different databases (MEDLINE, Scopus, Cochrane, LILACS, CINAHL, WOS), we found 363 registers with an accuracy of 12% (44 registers). After a full-text review, only 30 research studies were selected for qualitative synthesis and 11 for meta-analysis and meta-regression. The variables used were Crohn's disease activity index (CDAI), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). EN has been shown to have efficacy for the treatment of Crohn's disease and is compatible with other medicines. As for the CDAI or rates of remission, there were no differences between enteral and parenteral nutrition. Polymeric formulas have shown better results with respect to the CRP. The long-term treatment could dilute the good CDAI results that are obtained at the start of the EN treatment.

Butyrate production in patients with end-stage renal disease

Background: Chronic kidney disease (CKD) is associated with a decreased intestinal barrier function, causing bacterial translocation over the intestinal wall and triggering a systemic inflammatory response. Butyrate, a short-chain fatty acid produced by certain bacterial strains, is considered instrumental to keep the intestinal barrier intact. There are indications that a decreased amount of these specific bacterial species is part of the cause of the decreased intestinal barrier function in CKD. The aim of this study is (i) to determine if Dutch patients with end-stage renal disease (ESRD) have a decreased amount of butyrate-producing species and butyrate-producing capacity and (ii) whether this correlates with systemic inflammation. Methods: We used qPCR to evaluate the most abundant butyrate-producing species F. prauznitzii, E. rectale and Roseburia spp. and the BCoAT gene, which reflects the butyrogenic capacity of the intestinal microbiota. Fecal samples were collected from healthy kidney donors (n=15), preemptive renal transplant recipients (n=4) and dialysis patients (n=31). Markers of inflammation (CRP and IL-6) and intestinal permeability (D-lactate) were measured in plasma. Results: Patients with ESRD did not have a significantly decreased amount F. prauznitzii, E. rectale and Roseburia spp. or the BCoAT gene. Neither was there a significant correlation with CRP, IL-6 or D-lactate. On the individual level, there were some patients with decreased BCoAT levels and increased levels of CRP, IL-6 and D-lactate. Conclusions: Patients with ESRD do not have a decreased amount of the most abundant butyrate-producing species nor a decreased butyrate-producing capacity.

The possible association between AQP9 in the intestinal epithelium and acute liver injury‑induced intestinal epithelium damage

The present study aimed to investigate the expression and function of aquaporin (AQP)9 in the intestinal tract of acute liver injury rat models. A total of 20 Sprague Dawley rats were randomly divided into four groups: Normal control (NC) group and acute liver injury groups (24, 48 and 72 h). Acute liver injury rat models were established using D-amino galactose, and the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (Tbil) and albumin were determined using an automatic biochemical analyzer. Proteins levels of myosin light chain kinase (MLCK) in rat intestinal mucosa were investigated via immunohistochemistry. Pathological features were observed using hematoxylin and eosin (H&E) staining. MLCK, AQP9 and claudin-1 protein expression levels were detected via western blotting. Levels of ALT and AST in acute liver injury rats were revealed to steadily increase between 24 and 48 h time intervals, reaching a peak level at 48 h. Furthermore, TBil levels increased significantly until 72 h. Levels of ALT were revealed to significantly increase until the 48 h time interval, and then steadily decreased until the 72 h time interval. The acute liver injury 72 h group exhibited the greatest levels of MLCK expression among the three acute liver injury groups; however, all three acute liver injury groups exhibited enhanced levels of MLCK expression compared with the NC group. Protein levels of AQP9 and claudin-1 were enhanced in the NC group compared with the three acute liver injury groups. H&E staining demonstrated that terminal ileum mucosal layer tissues obtained from the acute liver injury rats exhibited visible neutrophil infiltration. Furthermore, the results revealed that levels of tumor necrosis factor-α, interleukin (IL)-6 and IL-10 serum cytokines were significantly increased in the acute liver injury groups. In addition, AQP9 protein expression was suppressed in acute liver injury rats, which induced pathological alterations in terminal ileum tissues may be associated with changes of claudin-1 and MLCK protein levels.

Phytic acid improves intestinal mucosal barrier damage and reduces serum levels of proinflammatory cytokines in a 1,2-dimethylhydrazine-induced rat colorectal cancer model

Phytic acid (PA) has been demonstrated to have a potent anticarcinogenic activity against colorectal cancer (CRC). Defects of the intestinal mucosal barrier and inflammation processes are involved in the development and progression of CRC. In the present study, we evaluated the effect of PA on the intestinal mucosal barrier and proinflammatory cytokines. After a 1-week acclimatisation period, sixty Wistar male rats were divided into the following five groups, with twelve rats per group: the control group (CG), model group (MG), low-PA-dose group (0·25 g/kg per d), middle-PA-dose group (0·5 g/kg per d), and high-PA-dose group (1 g/kg per d). 1,2-Dimethylhydrazine (DMH) at a dosage of 30 mg/kg of body weight was injected weekly to induce CRC for 18 weeks. We examined the expression of genes related to the intestinal mucosal barrier in the model. The results demonstrated that tumour incidence was decreased following PA treatment. The mRNA and protein expression of mucin 2 (MUC2), trefoil factor 3 (TFF3) and E-cadherin in the MG were significantly lower than those in the CG (P<0·05). The mRNA and protein expression of claudin-1 in the MG were significantly higher than those in the CG (P<0·05). PA elevated the mRNA and protein expression of MUC2, TFF3 and E-cadherin, and diminished the mRNA and protein expression of claudin-1. Furthermore, PA decreased serum levels of proinflammatory cytokines, which included TNF-α, IL-1β and IL-6. In conclusion, this study suggests that PA has favourable effects on the intestinal mucosal barrier and may reduce serum proinflammatory cytokine levels.

Open abdomen critical care management principles: resuscitation, fluid balance, nutrition, and ventilator management

The term "open abdomen" refers to a surgically created defect in the abdominal wall that exposes abdominal viscera. Leaving an abdominal cavity temporarily open has been well described for several indications, including damage control surgery and abdominal compartment syndrome. Although beneficial in certain patients, the act of keeping an abdominal cavity open has physiologic repercussions that must be recognized and managed during postoperative care. This review article describes these issues and provides guidelines for the critical care physician managing a patient with an open abdomen.

Chronic Kidney Disease Induced Intestinal Mucosal Barrier Damage Associated with Intestinal Oxidative Stress Injury

Background. To investigate whether intestinal mucosal barrier was damaged or not in chronic kidney disease progression and the status of oxidative stress. Methods. Rats were randomized into two groups: a control group and a uremia group. The uremia rat model was induced by 5/6 kidney resection. In postoperative weeks (POW) 4, 6, 8, and 10, eight rats were randomly selected from each group to prepare samples for assessing systemic inflammation, intestinal mucosal barrier changes, and the status of intestinal oxidative stress. Results. The uremia group presented an increase trend over time in the serum tumor necrosis factor-alpha, interleukin-6 (IL-6) and IL-10, serum D-lactate and diamine oxidase, and intestinal permeability, and these biomarkers were significantly higher than those in control group in POW 8 and/or 10. Chiu's scores in uremia group were also increased over time, especially in POW 8 and 10. Furthermore, the intestinal malondialdehyde, superoxide dismutase, and glutathione peroxidase levels were significantly higher in uremia group when compared with those in control group in POW 8 and/or 10. Conclusions. The advanced chronic kidney disease could induce intestinal mucosal barrier damage and further lead to systemic inflammation. The underlying mechanism may be associated with the intestinal oxidative stress injury.