Differential effect of oxidative stress on intestinal apparent permeability of drugs transported by paracellular and transcellular route

Restoration of intestinal barrier function by fexuprazan, a potassium-competitive acid blocker, in Caco-2 cells and its higher gastrointestinal distribution in rats

This study aimed to investigate the efficacy of fexuprazan in restoring intestinal barrier function in comparison with other potassium-competitive acid blockers (P-CABs) and esomeprazole. The effect of fexuprazan on trans-epithelial electrical resistance (TEER) value, mRNA and protein expression of tight junction genes, and cell morphology was investigated using a dextran sulfate sodium (DSS)-induced ulcerative colitis Caco-2 cell model. Treatment with fexuprazan, esomeprazole, tegoprazan, and vonoprazan significantly increased TEER values in a 3 % DSS-induced ulcerative colitis Caco-2 cells in a concentration-dependent manner. The TEER value-concentration profile showed sigmoidal shape curves and yielded half maximal effective concentration of 0.983 - 1.17 μg/mL for P-CABs and 3.27 μg/mL for esomeprazole. Among these drugs, fexuprazan showed the highest activity in the restoring intestinal barrier function. Fexuprazan also increased the expression of tight junction genes including zonula occludens-1, claudin 1, occludin, and mucin 1, and also thickened the epithelial cell membrane after treatment with 20 μg/mL fexuprazan. Fexuprazan showed a particularly high distribution in the liver and gastrointestinal tract in rats following oral administration of 2 mg/kg fexuprazan, which appears to be a positive characteristic of fexuprazan's effect on ulcerative colitis and gastric acid-related diseases although in vivo therapeutic efficacy of fexuprazan for ulcerative colitis requires further validation in both animal and human. In conclusion, fexuprazan can potentially restore intestinal barrier function by increasing the expression of tight junction genes and by strengthening the cell membrane integrity in DSS-induced colitis model.

Growth Performance and Gut Health of Cold-Stressed Broilers in Response to Supplementation with a Combination of Sodium Butyrate and Vitamin D3

The current experiment aimed to investigate the effects of sodium butyrate (SB) and vitamin D3 (VD3) supplementation on the growth performance, immune status, antioxidant capacity, and gut health of young broilers under cold stress. A total of 144 1-day-old Arbor Acres chicks were randomly allotted to three treatments with 6 replicates of 8 birds: (1) basal diet; (2) basal diet + cold stress; and (3) basal diet with 1 g/kg SB and 2000 IU/kg VD3 + cold stress. Birds were exposed to cold stress at 16 ± 1 °C for 72 h (d 18-21) and 26 ± 1 °C for the control. The results indicated that the SB/VD3 diet could alleviate the reduction in average daily gain (ADG) caused by cold stress (p < 0.05). The SB/VD3 diet decreased the serum endotoxin level and ileal interleukin-1β gene expression and upregulated interleukin-10 and nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression compared with cold-stressed birds (p < 0.05). Furthermore, cold stress altered the composition of gut microbiota, including a decrease in Clostridium_sensu_stricto_1, whereas the SB/VD3 diet prevented the reduction. In conclusion, the SB/VD3 diet mitigated the negative effects of cold stress on growth performance and the intestines by strengthening intestinal barrier function and stabilizing gut microbiota balance in broiler chicks, and these results can help to manage cold stress.

Shedding light on the impacts of Spirulina platensis on gut microbiota and related health benefits

Spirulina (S.) platensis is a blue-green algae with reported nutritional and health-promoting properties, such as immunomodulating, antioxidant, cholesterol-lowering properties, and beneficial effects on inflammatory diseases. Spirulina platensis can improve the function and composition of the gut microbiota and exert systemic beneficial effects. Gut dysbiosis is characterized by an imbalance in the composition and function of gut microbiota and is associated with several diseases. Some dietary bioactive compounds can restore the composition, diversity, and function of the gut microbiota and improve health-related parameters. This review proposes to gather relevant information on the effects of S. platensis supplementation on the modulation of the function and composition of gut microbiota and local and systemic measures related to gut health, such as inflammation, oxidative stress, and glucose and lipid metabolism. The body of evidence conducted with animals and clinical studies shows that S. platensis supplementation increased gut microbiota diversity and improved gut microbiota composition, as reported by a decrease in the Firmicutes/Bacteroides ratio, increase in the relative abundance of Prevotella and Lactobacillaceae, increase in short-chain fatty acid production and decrease of gut permeability. Improvements in gut microbiota have been associated with host health benefits such as anti-obesity, anti-diabetic, anti-hypertensive, anti-lipemic, anti-inflammatory, and antioxidant effects.

Mitochondrial DNA Release Contributes to Intestinal Ischemia/Reperfusion Injury

Mitochondria release many damage-associated molecular patterns (DAMPs) when cells are damaged or stressed, with mitochondrial DNA (mtDNA) being. MtDNA activates innate immune responses and induces inflammation through the TLR-9, NLRP3 inflammasome, and cGAS-STING signaling pathways. Released inflammatory factors cause damage to intestinal barrier function. Many bacteria and endotoxins migrate to the circulatory system and lymphatic system, leading to systemic inflammatory response syndrome (SIRS) and even damaging the function of multiple organs throughout the body. This process may ultimately lead to multiple organ dysfunction syndrome (MODS). Recent studies have shown that various factors, such as the release of mtDNA and the massive infiltration of inflammatory factors, can cause intestinal ischemia/reperfusion (I/R) injury. This destroys intestinal barrier function, induces an inflammatory storm, leads to SIRS, increases the vulnerability of organs, and develops into MODS. Mitophagy eliminates dysfunctional mitochondria to maintain cellular homeostasis. This review discusses mtDNA release during the pathogenesis of intestinal I/R and summarizes methods for the prevention or treatment of intestinal I/R. We also discuss the effects of inflammation and increased intestinal barrier permeability on drugs.

Spirulina platensis alleviates chronic inflammation with modulation of gut microbiota and intestinal permeability in rats fed a high-fat diet

Recent research suggested that taking a high-fat diet (HFD) may lead to a gut microbiota imbalance and colon tissue damage. This would lead to increased intestinal permeability and consequent constant circulation of low-grade inflammatory cytokines. Spirulina platensis can protect against HFD-induced metabolic inflammation and can stimulate the growth of beneficial bacteria in in vitro stool cultures. However, it is unknown whether this beneficial effect acts on intestinal tissues. In this study, rats were fed a high-fat diet fed with 3% S platensis for 14 weeks. We analysed endotoxin, the composition of the microbiota, inflammation and gut permeability. We found that S platensis decreased the bodyweight and visceral fat pads weight of the HFD-fed rats. In addition, it lowered the levels of lipopolysaccharide and pro-inflammatory cytokines in serum. Our results showed that S platensis could largely reduce the relative amount of Proteobacteria and the Firmicutes/Bacteroidetes ratio in faecal samples from HFD-fed rats. S platensis significantly reduced intestinal inflammation, as shown by decreased expression of myeloid differentiation factor 88 (MyD88), toll-like receptor 4 (TLR4), NF-κB (p65) and inflammatory cytokines. S platensis also ameliorated the increased permeability and decreased expression of tight junction proteins in the intestinal mucosa, such as ZO-1, Occludin and Claudin-1. Therefore, in HFD-induced gut dysbiosis rats, S platensis benefits health by inhibiting chronic inflammation and gut dysbiosis, and modulating gut permeability.

The Effect of Anesthetic Regimens on Intestinal Absorption of Passively Absorbed Drugs in Rats

PURPOSE

Different anesthetic regimens are used during single pass intestinal perfusion (SPIP) experiments for the study of intestinal drug absorption in rats. We examined the ketamine/xylazine anesthetic combination to evaluate its influence on drug absorption compared to older regimens. Additionally, we examined whether supplementary analgesia has any effect on drug absorption and the effect of the different anesthetic regimens on induction time and stress response.

METHODS

Rats were anesthetized using four different anesthetic regimens; ketamine/midazolam, pentobarbital, ketamine/xylazine and ketamine/xylazine/butorphanol. Three model drugs were administered to rat intestines and P_eff was calculated. Stress response was evaluated by quantifying blood corticosterone levels and induction time was recorded.

RESULTS

We found absorption under pentobarbital to be higher or similar to absorption under ketamine/midazolam. These results partly correlate with past literature data. Ketamine/xylazine was found to give similar or higher P_eff compared to pentobarbital and ketamine/midazolam. Addition of butorphanol did not affect absorption and reduced induction time and stress.

CONCLUSIONS

In studies of intestinal drug absorption, the ketamine/xylazine combination is superior to other anesthetic regimens as it is more convenient and seems to affect absorption to a lesser extent. Addition of butorphanol is highly recommended as it did not affect absorption but led to a more effective and less stress inducing experiment.

Pomegranate peel polyphenols reduce chronic low-grade inflammatory responses by modulating gut microbiota and decreasing colonic tissue damage in rats fed a high-fat diet

Recent studies have found that a high-fat diet (HFD) causes gut microbiota imbalance and colon tissue damage, resulting in increased intestinal permeability, which is one of the main reasons for the existence of constantly circulating low-grade inflammatory cytokines. Pomegranate extracts have been shown to protect from HFD-induced metabolic inflammation (e.g., colitis) and to promote the growth of beneficial bacteria in in vitro stool cultures. However, whether the beneficial effects of pomegranate extracts on the HFD-induced metabolic inflammation are achieved by acting on intestinal tissues has not yet been studied. In our present study, we found that pomegranate peel polyphenols (PPPs) alleviated HFD-induced obesity, elevated circulating pro-inflammatory cytokines, colonic tissue damage, and depressed colonic tight junction protein expression level in rats. Moreover, PPPs normalized the HFD-induced gut microbiota imbalance by increasing the abundance of beneficial bacteria in the colon. Furthermore, we also found that PPPs, punicalagin, and urolithin A (the main microbiota metabolites of pomegranate ellagitannins) all increased the LPS-induced decreased tight junction protein expression level and reversed the LPS-induced inflammatory response in Caco-2 cells. Urolithin A exhibited the best effects among the three pomegranate components. Our results suggested that the protective effects of PPPs in HFD-induced metabolic inflammation can be due to the recovery of colonic tissue damage and the regulation of gut microbiota and that urolithin A is the major component that contributes to the in vivo effects of PPPs.

L-tryptophan Enhances Intestinal Integrity in Diquat-Challenged Piglets Associated with Improvement of Redox Status and Mitochondrial Function

Simple Summary

In the present study, three groups of piglets were treated with diquat, a bipyridyl herbicide which can utilize molecular oxygen to generate superoxide anion radicals and is widely considered as an effective chemical agent for inducing oxidative stress. The three groups were fed a 0, 0.15%, and 0.30% tryptophan (Trp) supplemented diet, and one control group without diquat treatment was used to study the protective effects of supplemented Trp on growth performance and intestinal barrier function of piglets exposed to oxidative stress. The results showed that 0.15% Trp supplementation alleviated diquat-induced impaired growth performance, intestinal barrier injury, redox imbalance, and mitochondrial dysfunction. These findings from the current study suggest that piglets under the condition of stress might need more Trp to maintain intestinal integrity and optimal growth performance, but the proper dosage of Trp supplementation is needed to determine for different conditions or models.

Abstract

Tryptophan (Trp) supplementation has been shown to improve growth performance and enhance intestinal integrity in piglets. However, the effects of dietary Trp supplementation on the intestinal barrier function in piglets exposed to oxidative stress remain unknown. This study was conducted to evaluate whether dietary Trp supplementation can attenuate intestinal injury, oxidative stress, and mitochondrial dysfunction of piglets caused by diquat injection. Thirty-two piglets at 25 days of age were randomly allocated to four groups: (1) the non-challenged control; (2) diquat-challenged control; (3) 0.15% Trp-supplemented diet + diquat; (4) 0.30% Trp supplemented diet + diquat. On day seven, the piglets were injected intraperitoneally with sterilized saline or diquat (10 mg/kg body weight). The experiment lasted 21 days. Dietary supplementation with 0.15% Trp improved growth performance of diquat-challenged piglets from day 7 to 21. Diquat induced an increased intestinal permeability, impaired antioxidant capacity, and mitochondrial dysfunction. Although dietary supplementation with 0.15% Trp ameliorated these negative effects induced by diquat challenge that showed decreasing permeability of 4 kDa fluorescein isothiocyanate dextran, increasing antioxidant indexes, and enhancing mitochondrial biogenesis. Results indicated that dietary supplementation with 0.15% Trp enhanced intestinal integrity, restored the redox status, and improved the mitochondrial function of piglets challenged with diquat.

N-Acetylcysteine protects against intrauterine growth retardation-induced intestinal injury via restoring redox status and mitochondrial function in neonatal piglets

PURPOSE

Intrauterine growth retardation (IUGR) is detrimental to the intestinal development of neonates, yet satisfactory treatment strategies remain limited. This study was, therefore, conducted using neonatal piglets as a model to investigate the potential of N-acetylcysteine (NAC) to alleviate intestinal damage caused by IUGR.

METHODS

Seven normal birth weight (NBW) and fourteen IUGR neonatal male piglets were selected and then fed a basal milk diet (NBW-CON and IUGR-CON groups) or a basal milk diet supplemented with 1.2 g NAC per kg of diet (IUGR-NAC group) from 7 to 21 days of age (n = 7). Parameters associated with the severity of intestinal injury, villus morphology and ultrastructural structure, redox status, and mitochondrial function were analyzed.

RESULTS

Compared with the NBW-CON piglets, the IUGR-CON piglets exhibited decreased villus height and greater numbers of apoptotic cells in jejunum, along with the increases in malondialdehyde and protein carbonyl concentrations and a decreased adenosine triphosphate (ATP) content. Treatment with NAC significantly increased jejunal superoxide dismutase activity, reduced glutathione: oxidized glutathione ratio, and the mRNA abundance of nuclear respiratory factor 2, heme oxygenase 1, and superoxide dismutase 2 in the IUGR-NAC piglets compared with the IUGR-CON piglets. In addition, NAC improved the efficiency of mitochondrial oxidative metabolism and ATP generation, ameliorated mitochondrial swelling, and inhibited the overproduction of mitochondrial superoxide anion in the jejunal mucosa.

CONCLUSIONS

Dietary supplementation of NAC shows promise for attenuating the early intestinal injury of young piglets with IUGR, probably through its antioxidant action to restore redox status and mitochondrial function.

Intrauterine growth restriction in neonatal piglets affects small intestinal mucosal permeability and mRNA expression of redox-sensitive genes

Neonates with intrauterine growth restriction (IUGR) show lower efficiency of nutrient utilization compared to normal birth weight (NBW) newborns. This study was conducted using neonatal piglets as a model to test the hypothesis that IUGR affects the intestinal barrier function, intestinal structure, and antioxidant system development during the suckling period. The small intestinal mucosae were obtained from IUGR and NBW littermates in the suckling period (d 0, 3, 8, and 19 postnatal). The epithelial barrier function was assessed by FITC-dextran 4 (FD4) and horseradish peroxidase (HRP) fluxes across the epithelium, histomorphologic measurements, and expression of tight-junction proteins. Redox status represented by the glutathione disulfide/glutathione ratio and malondialdehyde concentrations was determined, whereas mRNA expressions of some redox-sensitive proteins were quantified. Results showed that IUGR piglets exhibited a 2-fold higher intestinal permeability in the proximal small intestine on d 0 (P < 0.05), and this difference between IUGR and NBW piglets was widened to 3 and 4 times for FD4 and HRP, respectively (P < 0.05), on d 3. In accordance, expression of occludin was down-regulated at the transcriptional level in IUGR piglets at d 0 and 19 (P < 0.01). Furthermore, the transcription of heme oxygenase 1, catalase, and thioredoxin reductase genes was down-regulated in IUGR piglets, mainly on postnatal d 0 and 19 (P < 0.01). It appears that IUGR subjects have a lower capacity to mount an antioxidant response in the early postnatal period. Collectively, these results add to our understanding of the mechanisms responsible for intestinal dysfunction in IUGR neonates.