Serum D-lactate Levels Research Articles

Cow Placenta Extract Ameliorates Cyclophosphamide-Induced Intestinal Damage by Enhancing the Intestinal Barrier, Improving Immune Function, and Restoring Intestinal Microbiota

Immunosuppression undermines intestinal barrier integrity. Cow placenta extract (CPE) primarily consists of active peptides with immunomodulatory and antioxidant effects. This study aimed to examine the preventive effect of CPE against intestinal damage induced by cyclophosphamide (Cy) in immunosuppressed mice. Thirty-six mice were randomly allocated into three groups: control group (C), model group (M), and treatment group (CPE). The mice in the CPE group were provided with 1500 mg/kg/day of CPE via gavage. In the last 3 days, mice in the groups M and CPE received intraperitoneal injections of 80 mg/kg/day of Cy. The results showed that CPE improved intestinal barrier function by decreasing serum d-Lactate (D-LA) levels and diamine oxidase (DAO) activity, while elevating the relative expression of Occludin, zonula occludens-1 (ZO-1), and mucin-2 (MUC-2) mRNA. Additionally, CPE improved the immune organ index and elevated the levels of secretory immunoglobulin A (sIgA), superoxide dismutase (SOD), interleukin-1beta (IL-1β), interleukin-4 (IL-4), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) in the intestine, thereby enhancing intestinal mucosal immune function. Furthermore, CPE improved the diversity of intestinal microbiota and increased the abundance of Candidatus_Saccharimonas, Psychrobacter, and Enterorhabdus, which promoted the proper functioning of the intestines. These findings suggest that CPE effectively ameliorates Cy-induced intestinal damage by enhancing the intestinal barrier, improving immune function, and restoring intestinal microbiota.

Fermented Purslane (Portulaca oleracea L.) Supplementation Enhances Growth and Immune Function Parallel to the Regulation of Gut Microbial Butyrate Production in Weaned Piglets.

Weaning is a challenging period for piglets, characterized by stress-related growth checks, compromised immunity, and gut dysbiosis. Purslane (Portulaca oleracea L.), known for its rich content of antioxidants, has potential as a functional feed ingredient. This study investigates the effects of feeding fermented purslane (FP) on the growth performance, immune function, intestinal microbiota, and metabolic profiles of weaned piglets. Forty-eight weaned piglets were randomly divided into two groups, with eight pens in each group and three pigs in each pen: a control diet (CON group) and a diet supplemented with 0.20% FP (FP group). The experiment lasted 28 days. The results show that FP supplementation did not affect the average daily feed intake (ADFI) but significantly increased the average daily gain (ADG) during the initial 14 days post-weaning. FP supplementation decreased diarrhea occurrence, with a pronounced reduction from days 10 to 13 (p < 0.05). Immunologically, the FP group had a trend towards reduced serum IgA levels on day 14 (p < 0.10). Importantly, the serum concentrations of the pro-inflammatory cytokine IL-6 were significantly reduced on both days 14 and 28 post-weaning. The antioxidative analysis showed increased serum superoxide dismutase (SOD) and decreased catalase (CAT) activities on day 14 (p < 0.05). In addition, FP supplementation significantly decreased serum diamine oxidase (DAO) activity and D-lactate levels by day 28, indicating a potential improvement in gut integrity. Fecal microbiota assessment demonstrated a distinctive clustering of microbial communities between the FP and CON groups, with an increase in the abundance of Clostridium_sensu_stricto_1, Tyzzerella, and Prevotellaceae_NK3B31_group and a decrease in Lactobacillus, Bacillus, and Subdoligranulum in the FP group (p < 0.05). Functional predictions suggested that the relative abundance of microbial butyrate synthesis enzymes (EC 2.7.2.7 and EC 2.3.1.19) was significantly enhanced by FP treatment. This modulation was further corroborated by elevated fecal butyrate levels (p < 0.05). In summary, dietary supplementation with FP promotes early-growth performance and has beneficial effects on immune function and intestinal health in weaned piglets. The enhancements may be attributed to distinct microbiota compositional changes and targeted modulation of microbial butyrate metabolism, which are crucial for piglet post-weaning adaptation and overall health.

Dietary supplementation with a silicate clay mineral (palygorskite) alleviates inflammatory responses and intestinal barrier damage in broiler chickens challenged with Escherichia coli

This experiment aimed to explore the protective effects of dietary palygorskite (Pal) supplementation on inflammatory responses and intestinal barrier function of broiler chickens challenged with Escherichia coli (E. coli). A 2 × 2 factorial arrangement was designed to assess the effects of Pal administration (0 or 5 g/kg of feed) and E. coli challenge (E. coli or bacterial culture medium) on broilers in a 21-d feeding trial. Birds were randomly assigned into one of the 4 groups, and each group had 8 replicates with ten birds each. The challenged chickens were orally gavaged with E. coli suspended in Luria-Bertani broth on 14 d of age, while unchallenged birds were administrated with an equivalent amount of culture medium. The sampling was performed at 21 d of age. Compared with the normal birds, an oral E. coli challenge reduced final body weight, and decreased feed intake, weight gain, and feed efficiency during the challenge period (P < 0.05). E. coli challenge promoted colonization of E. coli in cecal content and their translocation to internal organs (heart, liver, and spleen) (P < 0.05). E. coli infection also increased levels of pro-inflammatory cytokines in jejunum and ileum possibly through activating the toll-like receptor-4-mediated signaling pathway (P < 0.05). Moreover, E. coli administration increased intestinal mucosal permeability (higher serum D-lactate level and diamine oxidase activity, and lower intestinal mucosal disaccharidase activities), altered intestinal morphology, and downregulated the gene expression of intestinal tight junction proteins (P < 0.05). In contrast, Pal supplementation enhanced growth performance, inhibited colonization of E. coli, reduced intestinal inflammation, decreased intestinal permeability, restored intestinal morphology, and normalized the expression of genes responsible for inflammatory processes and maintenance of intestinal mucosal barrier (P < 0.05), and most of these beneficial effects resulting from Pal administration were independent of bacterial challenge. The results indicated dietary Pal incorporation was effective in improving growth performance and alleviating inflammation and intestinal mucosal barrier damage in broilers challenged with E. coli.

Inhibition of Pck1 in intestinal epithelial cells alleviates acute pancreatitis via modulating intestinal homeostasis.

Intestinal barrier dysfunction usually occurred in acute pancreatitis (AP) but the mechanism remains unclear. In this study, RNA sequencing of ileum in L-arginine-induced AP mice demonstrated that phosphoenolpyruvate kinase 1 (Pck1) was significantly up-regulated. Increased Pck1 expression in intestinal epithelial cells (IECs) was further validated in ileum of AP mice and duodenum of AP patients. In AP mice, level of Pck1 was positively correlated with pancreatic and ileal histopathological scores, serum amylase activity, and intestinal permeability (serum diamine oxidase (DAO), D-lactate, and endotoxin). In AP patients, level of Pck1 had a positive correlation with Ranson scores, white blood cell count and C-reactive protein. Inhibition of Pck1 by 3-Mercaptopicolinic acid hydrochloride (3-MPA) alleviated pancreatic and ileal injuries in AP mice. AP + 3-MPA mice showed improved intestinal permeability, including less epithelial apoptosis, increased tight junction proteins (TJPs) expression, decreased serum DAO, D-lactate, endotoxin, and FITC-Dextran levels, and reduced bacteria translocation. Lysozyme secreted by Paneth cells and mucin2 (MUC2) secretion in goblet cells were also partly restored in AP + 3-MPA mice. Meanwhile, inhibition of Pck1 improved intestinal immune response during AP, including elevation of M2/M1 macrophages ratio and secretory immunoglobulin A (sIgA) and reduction in neutrophils infiltration. Invitro, administration of 3-MPA dramatically ameliorated inflammation and injuries of epithelial cells in enteroids treated by LPS. In conclusion, inhibition of Pck1 in IECs might alleviate AP via modulating intestinal homeostasis.

Impacts of pyraclostrobin on intestinal health and the intestinal microbiota in common carp (Cyprinus carpio L.)

Pyraclostrobin (PYR) is a strobilurin fungicide that is commonly used in agriculture, and its use in agriculture may lead to an increase in its residue in the aquatic environment and may have a deleterious influence on the intestinal health of aquatic creatures. Here, common carp were chronically exposed to PYR (0, 0.5, or 5.0 μg/L) for 30 d to determine its effect on the physical and immunological barrier and intestinal microbiota in the intestine. PYR exposure caused significant histological changes; altered the mRNA expression levels of occludin, claudin-2, and zonula occludens-1 (ZO-1); induced oxidative stress in the common carp intestine; and increased the serum D-lactate and diamine oxidase (DAO) levels. Moreover, PYR significantly increased the protein expression levels of tumour necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and IL-6 while decreasing the level of transforming growth factor beta (TGF-β). Further studies revealed that PYR significantly reduced lysozyme (LZM) and acid phosphatase (ACP) activities as well as complement 3 (C3) and immunoglobulin M (IgM) levels. Furthermore, PYR decreased gut microbial diversity while increasing the abundance of pathogenic bacteria such as Aeromonas and Shewanella, causing an intestinal microbial disturbances in common carp. These results imply that PYR has a negative impact on fish intestinal health and may pose serious health risks to fish by disrupting the intestinal microbiota, physical barrier, and immunological barrier in common carp.

Cysteine Attenuates the Impact of Bisphenol A-Induced Oxidative Damage on Growth Performance and Intestinal Function in Piglets.

Bisphenol A (BPA), a kind of environmental toxin, widely impacts daily life. Cysteine (Cys) is a nutritionally important amino acid for piglets. However, it remains unclear whether Cys can alleviate BPA-induced oxidative damage in piglets. The aim of the present study was to explore the protective effects of Cys in BPA-challenged piglets. A total of twenty-four piglets were divided into four groups that were further subdivided based on the type of exposure (with or without 0.1% BPA) in a basal or Cys diet for a 28 d feeding trial. The results showed that BPA exposure decreased the piglets' average daily weight gain by 14.9%, and decreased dry matter, crude protein and ether extract digestibility by 3.3%, 4.5% and 2.3%, respectively; these decreases were attenuated by Cys supplementation. Additionally, Cys supplementation restored BPA-induced decreases in superoxide dismutase (SOD) and glutathione (GSH), and increases in malondialdehyde (MDA) levels, in the serum and jejunum (p < 0.05). Moreover, BPA decreased the jejunal mRNA expression of antioxidant genes, which were restored by Cys supplementation (p < 0.05). Cys also restored BPA and increased serum D-lactate levels and diamine oxidase (DAO) activity, and BPA decreased jejunal disaccharidase activity (p < 0.05). Further investigations in this study showed that the protective effects of Cys were associated with restoring intestinal barrier integrity by improving the jejunal morphology and enhancing the mRNA expression of tight junction proteins (p < 0.05). Collectively, the results herein demonstrated that Cys supplementation attenuated the impact of BPA-induced oxidative damage on growth performance, nutrient digestibility and intestinal function.

Effects of glutamine, glutamate, and aspartate on intestinal barrier integrity and amino acid pool of the small intestine in piglets with normal or low energy diet.

Aspartate (asp), glutamate (glu), and glutamine (gln) are the major energy fuels for the small intestine, and it had been indicated in our previous study that the mix of these three amino acid supplementations could maintain intestinal energy homeostasis. This study aimed to further investigate whether the treatment of gln, glu, and asp in low energy diet affects the intestinal barrier integrity and amino acid pool in weaning piglets. A total of 198 weaned piglets were assigned to 3 treatments: control (basal diet + 1.59% L-Ala); T1 (basal diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp); and T2 (low energy diet + 1% L-Gln + 0.5% L-Glu + 0.1% L-Asp). The blood, jejunum, and ileum were obtained on day 5 or on day 21 post-weaning, respectively. Our results showed that T1 and T2 treatments increased the abundances of occludin, claudin-1, and claudin-3 in the small intestine while decreasing the serum diamine oxidase (DAO) and D-lactate levels in weaning piglets. Meanwhile, T1 and T2 treatments significantly increased the positive rate of proliferating cell nuclear antigen (PCNA) of the small intestine, promoting intestinal cell proliferation. We also found that supplementation with glu, gln, and asp improved the serum amino acid pool and promoted ileal amino acid transporter gene expression of slc3a2, slc6a14, and slc7a11 in weaned piglets. Additionally, on day 21 post-weaning, T1 and T2 treatments stimulated the phosphorylation of the mTOR-S6K1-4EBP1 signaling pathway in the small intestine, which may implicate the enhanced protein synthesis rate. In summary, dietary supplementation of gln, glu, and asp was beneficial to the intestinal barrier function and amino acid pool regulation, while the benefits of gln, glu, and asp treatment might be diminished by the low-energy diet. The results demonstrated that the supplementation of gln, glu, and asp under low energy levels was preferentially supplied as the energy fuel to restore the gut barrier function in piglets on day 5 post-weaning. With the increase in age and intestinal maturation (on day 21 post-weaning), gln, glu, and asp supplementation could also show an effect on the regulation of the amino acid pool and protein synthesis.

Lafutidine Ameliorates Indomethacin-Induced Small Intestinal Damage in Rats by Modifying the Intestinal Mucosal Barrier, Inflammation, and Microbiota

Introduction: Nonsteroidal anti-inflammatory drug (NSAID)-induced small intestinal damage is a serious and escalating clinical problem without effective treatment. Lafutidine (LAF) is a novel histamine H2 receptor antagonist with a mucosal protective action. This study aimed to investigate the protective effect of LAF on indomethacin (IND)-induced enteropathy in rats. Methods: Rats were treated with LAF for 10 days with concomitant IND treatment on the final 5 days. Changes in metabolism and hematological and biochemical parameters were measured, and intestinal damage was blindly scored. Intestinal mucosal tissue and luminal contents were collected for transcriptome and microbiota sequencing. Intestinal inflammation and barrier function were also evaluated. Results: LAF treatment prevented anorexia and weight loss in rats and ameliorated reductions in hemoglobin, hematocrit, total protein, and albumin levels. LAF reduced the severity of IND-induced intestinal damage including macroscopic and histopathological damage score. Transcriptome sequencing results indicated that LAF might have positive effects on intestinal inflammation and the intestinal mucosal barrier. Further research revealed that LAF decreased neutrophil infiltration, and IL-1β and TNF-α expression in intestinal tissue. Besides, the treatment increased mucus secretion, MUC2, Occludin, and ZO-1 expression, and decreased serum D-lactate levels. LAF treatment also ameliorates microbial dysbiosis in small intestine induced by IND and increased the abundance of Lactobacillus acidophilus. Conclusion: LAF may protect against NSAID enteropathy via enhancing the intestinal mucosal barrier, inhibiting inflammation, and regulating microbiota.

PLK1 protects intestinal barrier function in sepsis: A translational research.

Sepsis and its related complications are very challenging in the intensive care unit, among which intestinal barrier injury is a general manifestation. Polo-like kinase 1 (PLK1) is widely studied in cancer, while its role in sepsis is poorly understood. In this study, the efficiency of PLK1 as a marker of intestinal barrier function as well as a predictor of mortality in sepsis was evaluated. The level of serum PLK1 was measured in septic patients (n=51) and controls (n=20); subsequently, its correlation with serum diamine oxidase (DAO), d-lactate, and endotoxin levels and its ability topredict mortality were analysed. The survival rate and barrier injury degree were also assessed in septic mice. Serum PLK1 levels were elevated in septic patients, were negatively correlated with serum DAO, d-lactate, and endotoxin levels, and had a high predictive value for 28-day mortality in patients. The serum PLK1 level in non-survivors was lower. The expression of PLK1 in the intestine was decreased in septic mice, and overexpression or inhibition of PLK1 alleviated or aggravated intestinal barrier injury, respectively, as evaluated by Chiu's score, serum levels of DAO and d-lactate, and expression of tight junction proteins. Overexpressing PLK1 also decreased the 72-hour death rate of septic mice. Further study also revealed the negative correlation of PLK1 and IL-6 in patients, and increasing or interfering with PLK1 expression reduced or increased the serum IL-6 level in mice. PLK1 plays a critical role in intestinal barrier function during sepsis, providing a novel perspective for sepsis therapy in the clinic.

A blend of formic acid, benzoic acid, and tributyrin alleviates ETEC K88-induced intestinal barrier dysfunction by regulating intestinal inflammation and gut microbiota in a murine model

This study aimed to investigate the effects of an organic acid (OA) blend on intestinal barrier function, intestinal inflammation, and gut microbiota in mice challenged with enterotoxigenic Escherichia coli K88 (ETEC K88). Ninety female Kunming mice (7weeks old) were randomly allotted to five treatments with six replicates per treatment and three mice per replicate. The five treatments were composed of the non-ETEC K88 challenge group and ETEC K88 challenge+OA blend groups (0, 0.6%, 1.2%, and 2.4% OA blend). The OA blend consisted of 47.5% formic acid, 47.5% benzoic acid, and 5% tributyrin. The feeding trial lasted for 15days, and mice were intraperitoneally injected with PBS or ETEC K88 solution on day 15. At 24h post-challenge, one mouse per replicate was selected for sample collection. The results showed that a dosage of 0.6% OA blend alleviated the ETEC K88-induced intestinal barrier dysfunction, as indicated by the elevated villus height and the ratio of villus height to crypt depth of jejunum, and the reduced serum diamine oxidase (DAO) and D-lactate levels, as well as the up-regulated mRNA levels of ZO-1, Claudin-1, and Occludin in jejunum mucosa of mice. Furthermore, dietary addition with 0.6% OA blend decreased ETEC K88-induced inflammation response, as suggested by the decreased TNF-α and IL-6 levels, and the increased IgA level in the serum, as well as the down-regulated mRNA level of TNF-α, IL-6, IL-1β, TLR-4, MyD88, and MCP-1 in jejunum mucosa of mice. Regarding gut microbiota, the beta-diversity analysis revealed a remarkable clustering between the 0.6% OA blend group and the ETEC K88 challenge group. Supplementation of 0.6% OA blend decreased the relative abundance of Firmicutes, and increased the relative abundance of Bacteroidota, Desulfobacterota, and Verrucomicrobiota of colonic digesta in mice. Also, the butyric acid content in the colonic digesta of mice was increased by dietary 0.6% OA blend supplementation. Collectively, a dosage of 0.6% OA blend could alleviate the ETEC K88-induced intestinal barrier dysfunction by regulating intestinal inflammation and gut microbiota of mice.

Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells

BackgroundIntestinal barrier plays key roles in maintaining intestinal homeostasis. Inflammation damage can severely destroy the intestinal integrity of mammals. This study was conducted to investigate the protective effects of embelin and its molecular mechanisms on intestinal inflammation in a porcine model. One hundred sixty 21-day-old castrated weaned pigs (Duroc × Landrace × Yorkshire, average initial body weight was 7.05 ± 0.28 kg, equal numbers of castrated males and females) were allotted to four groups and fed with a basal diet or a basal diet containing 200, 400, or 600 mg embelin/kg for 28 d. The growth performance, intestinal inflammatory cytokines, morphology of jejunum and ileum, tight junctions in the intestinal mucosa of piglets were tested. IPEC-1 cells with overexpression of P300/CBP associating factor (PCAF) were treated with embelin, the activity of PCAF and acetylation of nuclear factor-κB (NF-κB) were analyzed to determine the effect of embelin on PCAF/NF-κB pathway in vitro.ResultsThe results showed that embelin decreased (P < 0.05) serum D-lactate and diamine oxidase (DAO) levels, and enhanced the expression of ZO-1, occludin and claudin-1 protein in jejunum and ileum. Moreover, the expression levels of critical inflammation molecules (interleukin-1β, interleukin-6, tumor necrosis factor-α, and NF-κB) were down-regulated (P < 0.05) by embelin in jejunal and ileal mucosa. Meanwhile, the activity of PCAF were down-regulated (P < 0.05) by embelin. Importantly, transfection of PCAF siRNAs to IPEC-1 cell decreased NF-κB activities; embelin treatment downregulated (P < 0.05) the acetylation and activities of NF-κB by 31.7%–74.6% in IPEC-1 cells with overexpression of PCAF.ConclusionsThese results suggested that embelin ameliorates intestinal inflammation in weaned pigs, which might be mediated by suppressing the PCAF/NF-κB signaling pathway.

Laying performance, egg quality, fertility, nutrient digestibility, digestive enzymes activity, gut microbiota, intestinal morphology, antioxidant capacity, mucosal immunity, and cytokine levels in meat-type Japanese quail breeders fed different phytogenic levels

A total of 180 female Japanese quail breeders were allocated to 5 treatments with 6 replicates of 6 birds and fed a diet supplemented with 0, 125, 250, 500, or 1000 mg/kg of a phytogenic feed additive (PFA) in a 9-wk experiment. Egg weight, feed efficiency, shell breaking strength and calcium content, specific gravity, Haugh unit, and percentages of fertile eggs increased with increasing PFA levels (P < 0.05). Increasing of PFA levels increased nutrient digestibility, dietary AMEn, and activities of digestive enzymes in the pancreas and intestinal digesta (P < 0.05). Supplementation of PFA reduced Escherichia coli (P < 0.05), Clostridium spp. (P < 0.05) and Salmonella spp. counts (P < 0.05), while increased Lactobacillus and Bifidobacterium spp. counts in the ileal and cecal contents (P < 0.05). Dietary PFA increased jejunal villus height and decreased ileal crypt depth (P < 0.05). Serum diamine oxidase activity and D-lactate level were decreased with increase in PFA level (P < 0.05). Increasing PFA levels increased glutathione peroxidase activity in the pancreas, small intestine, and cecal tonsil, but decreased malondialdehyde contents (P < 0.05). Birds fed PFA exhibited increased levels of secretory IgA in the intestinal mucosa (P < 0.05), and increased the percentage of CD3+ T cells, ratio of CD4+/CD8+ T cells, and cytokine concentrations in the cecal tonsils (P < 0.05). In conclusion, PFA could improve gut health and nutrient utilization and, therefore, benefit productivity, egg quality, and fertility in quails.

Gastrointestinal digestibility insights of different levels of coated complex trace minerals supplementation on growth performance of yellow-feathered broilers.

This study was designed to evaluate the optimum additional level of coated complex trace minerals (TMs) and its impacts on the growth performance of broilers through measurement of digestibility of nutrients and intestinal development. In a 56-day trial, a total of 360 one-day-old male yellow-feathered broilers were randomly divided into six dietary treatment groups. Each treatment contained six replicates, with 10 birds. The control group was supplemented with 1,000 mg/kg of uncoated complex TMs in the basal diet (UCCTM1000). The remaining 5 treatments were degressively supplemented with coated complex TMs from 1,000 to 200 mg/kg in the basal diet, which were considered as (CCTM1000), (CCTM800), (CCTM600), (CCTM400), (CCTM200), respectively. Results: On comparing the UCCTM1000 supplementation, the CCTM1000 supplementation decreased the feed to gain ratio (F/G) (P < 0.05), increased digestibility of crude protein (CP) (P < 0.05), crude fat (CF) (P < 0.05), villus height (VH) of duodenum (P < 0.05), and the mRNA expression level of occludin in jejunal mucosa (P < 0.05). In addition, the F/G was lower in the CCTE600 group than that in the CCTE200 group (P < 0.05). The VH to crypt depth (CD) ratio (V/C) of jejunum and ileum in the CCTM400 and CCTM600 groups was higher (P < 0.05) than that in the CCTM1000 group. The serum endotoxin and D-lactate level and CP digestibility were increased by dietary coated complex TMs addition level. The mRNA expression levels of claudin-1 and ZO-1 in the CCTM600 group were higher (P < 0.05) than that in the CCTM1000 group. In conclusion, adding 600 mg/kg of coated complex TMs showed the minimum F/G and the maximum crude protein digestibility and intestine development of yellow-feathered broilers compared with other treatments. This supplementation level of coated complex TMs could totally replace 1,000 mg/kg of uncoated complex TMs to further decrease the dose of TMs and raise economic benefit.

Correlation between Intestinal Microflora in Irritable Bowel Syndrome and Severity.

Background Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disease accompanied by changes in intestinal microecology. This study investigated the relationship between gut microbiota and disease severity in patients with irritable bowel syndrome (IBS). Methods An observational study was performed on 60 IBS patients (study group) and 20 healthy controls admitted to our hospital from January 2013 to December 2014. Fecal samples were taken after admission to measure intestinal flora including Bifidobacterium, Lactobacillus, Enterobacter, and Enterococcus, and patient blood was collected to determine serum D-lactate and diamine oxidase (DAO) levels. The gut microbiota and serum markers of the two groups were analyzed. The correlation of gut microbiota index levels and serum markers with disease severity, as well as the correlation between gut microbiota index levels and serum markers, were analyzed. Results The levels of intestinal Lactobacillus and Bifidobacterium were lower, while the levels of Enterococcus and Enterobacter and serum D-lactate were higher in the study group than those in the control group. The levels of intestinal Lactobacillus and Bifidobacterium were lower, while the levels of Enterococcus and Enterobacter, serum D-lactate, and DAO were higher in patients with moderate IBS than those in patients with mild IBS. The levels of intestinal Lactobacillus and Bifidobacterium were lower in patients with severe IBS than those with moderate IBS, while the levels of Enterococcus and Enterobacter, serum D-lactate, and DAO were higher in patients with severe IBS. There was a significant negative correlation between the levels of Lactobacillus and Bifidobacterium and disease severity and a significant positive correlation between the levels of Enterococcus and Enterobacter, D-lactate, and DAO and disease severity. There was a significant negative correlation between the levels of Lactobacillus and Bifidobacterium and serum D-lactate and DAO, while there was a significant positive correlation between the levels of Enterococcus and Enterobacter and serum D-lactate and DAO (P < 0.05). Conclusion Intestinal flora, D-lactate, and DAO were abnormal in IBS patients, and intestinal flora was closely correlated with disease severity, D-lactate, and DAO levels.

An Antioxidant Supplement Function Exploration: Rescue of Intestinal Structure Injury by Mannan Oligosaccharides after Aeromonas hydrophila Infection in Grass Carp (Ctenopharyngodon idella).

Mannan oligosaccharides (MOS) are a type of functional oligosaccharide which have received increased attention because of their beneficial effects on fish intestinal health. However, intestinal structural integrity is a necessary prerequisite for intestinal health. This study focused on exploring the protective effects of dietary MOS supplementation on the grass carp’s (Ctenopharyngodon idella) intestinal structural integrity (including tight junction (TJ) and adherent junction (AJ)) and its related signalling molecule mechanism. A total of 540 grass carp (215.85 ± 0.30 g) were fed six diets containing graded levels of dietary MOS supplementation (0, 200, 400, 600, 800 and 1000 mg/kg) for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila for 14 days. We used ELISA, spectrophotometry, transmission electron microscope, immunohistochemistry, qRT-PCR and Western blotting to determine the effect of dietary MOS supplementation on intestinal structural integrity and antioxidant capacity. The results revealed that dietary MOS supplementation protected the microvillus of the intestine; reduced serum diamine oxidase and d-lactate levels (p < 0.05); enhanced intestinal total antioxidant capacity (p < 0.01); up-regulated most intestinal TJ and AJ mRNA levels; and decreased GTP-RhoA protein levels (p < 0.01). In addition, we also found several interesting results suggesting that MOS supplementation has no effects on ZO-2 and Claudin-15b. Overall, these findings suggested that dietary MOS supplementation could protect intestinal ultrastructure, reduce intestinal mucosal permeability and maintain intestinal structural integrity via inhibiting MLCK and RhoA/ROCK signalling pathways.

The Gut-Liver Axis in Nonalcoholic Fatty Liver Disease: Association of Intestinal Permeability with Disease Severity and Treatment Outcomes.

Objective To investigate the association between intestinal permeability and severity of nonalcoholic fatty liver disease (NAFLD) and the value of intestinal permeability in predicting the efficacy of metabolic therapy for NAFLD. Methods Disease severity was compared between patients with normal and elevated intestinal permeability; correlations between D-lactate and different NAFLD parameters were analyzed; and the effects of metabolic therapy on NAFLD patients with normal and elevated intestinal permeability were evaluated. Results A total of 190 patients with NAFLD were enrolled. NAFLD patients with elevated intestinal permeability had significantly higher levels of liver test parameters, liver ultrasonographic fat attenuation parameter, triglyceride, homeostasis model assessment of insulin resistance value, and diamine oxidase (all P˂0.05) than NAFLD patients with normal intestinal permeability. Furthermore, serum D-lactate levels were positively correlated with alanine transaminase, aspartate transaminase, gamma-glutamyl transpeptidase, total bilirubin, indirect bilirubin, fat attenuation parameter, triglyceride, and diamine oxidase (all P ˂ 0.05). Moreover, NAFLD patients with elevated intestinal permeability showed less improvement in TG levels (P = 0.014) after metabolic therapy. Conclusion Intestinal permeability correlates with the disease severity in patients with NAFLD. Moreover, intestinal permeability may have value for predicting the efficacy of metabolic therapy for NAFLD patients.

Effects of L-theanine on intestinal morphology, barrier function, and MAPK signaling pathways in diquat-challenged piglets

This study aimed to explore the protective effects of L-theanine supplementation on the diquat-challenged weaned piglets. A total of 160 weaned piglets were randomly divided into 4 groups using a 2 × 2 two-factor design, there were 4 replicates per group and 10 pigs per replicate. Piglets were fed diets (with 1000 mg/kg L-theanine addition or not), then challenged with diquat or saline on day 7. 21 days after challenge, two pigs from each replicate were selected for sample collection. Results showed that supplement with 1000 mg/kg L-theanine down-regulated the diarrhea rate, serum D-lactate level, tumor necrosis factor-α, and phosphorylation of extracellular regulated protein kinases (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) signaling in pigs without diquat challenge (p < 0.05). While for diquat-challenged piglets, L-theanine addition increased average daily gain, jejunum villus height, and interferon-γ level (p < 0.05). Meanwhile, L-theanine addition decreased the diarrhea rates and mortality, serum D-lactate level, and phosphorylation of ERK and JNK in diquat-challenged pigs (p < 0.05). These results demonstrate that L-theanine pretreatment could alleviate diquat-induced oxidative stress and improve intestinal barrier function in diquat-challenged weaned piglets, which can be attributed to suppression of MAPK phosphorylation signaling pathways.

CCAAT/Enhancer-Binding Protein Homologous Protein (CHOP) Deficiency Attenuates Heatstroke-Induced Intestinal Injury

The intestine is one of the main target organs involved in the pathological process of heatstroke. CCAAT/enhancer-binding protein homologous protein (CHOP) is involved in endoplasmic reticulum (ER) stress-induced apoptosis. This study aimed to explore the role of CHOP in heatstroke-induced intestinal injury and potential therapy. An in vitro heat stress (HS) model using Caco-2 cells was employed. We observed the role of CHOP in apoptosis-mediated intestinal epithelial cell injury secondary to HS by evaluating cell viability, lactate dehydrogenase release, apoptosis levels, and GRP78, PERK, ATF4, CHOP, Bcl-2, and BAX mRNA and protein expression. To further study the role of CHOP in HS-induced intestinal barrier dysfunction, we assessed transepithelial electrical resistance, paracellular tracer flux, ultrastructure of tight junctions, and protein expression of ZO-1 and occludin. Male wild-type mice and CHOP knockout mice were used for in vivo experiments. We evaluated serum d-lactate and diamine oxidase levels, histopathological changes, intestinal ultrastructure, and ZO-1 and occludin protein expression. HS activated the PERK-CHOP pathway and promoted apoptosis by upregulating BAX and downregulating Bcl-2; these effects were prevented by CHOP silencing. Intestinal epithelial barrier function was disrupted by HS in vitro and in vivo. CHOP silencing prevented intestinal barrier dysfunction in Caco-2 cells, whereas CHOP knockout mice exhibited decreased intestinal mucosal injury. The ER stress inhibitor 4-phenylbutyrate (4-PBA) prevented HS-induced intestinal injury in vitro and in vivo. This study indicated that CHOP deficiency attenuates heatstroke-induced intestinal injury and may contribute to the identification of a novel therapy against heatstroke associated with the ER stress pathway.

Few-Layer MoS2 Photodetector Arrays for Ultrasensitive On-Chip Enzymatic Colorimetric Analysis.

Enzymatic colorimetric analysis of metabolites provides signatures of energy conversion and biosynthesis associated with disease onsets and progressions. Miniaturized photodetectors based on emerging two-dimensional transition metal dichalcogenides (TMDCs) promise to advance point-of-care diagnosis employing highly sensitive enzymatic colorimetric detection. Reducing diagnosis costs requires a batched multisample assay. The construction of few-layer TMDC photodetector arrays with consistent performance is imperative to realize optical signal detection for a miniature batched multisample enzymatic colorimetric assay. However, few studies have promoted an optical reader with TMDC photodetector arrays for on-chip operation. Here, we constructed 4 × 4 pixel arrays of miniaturized molybdenum disulfide (MoS2) photodetectors and integrated them with microfluidic enzyme reaction chambers to create an optoelectronic biosensor chip device. The fabricated device allowed us to achieve arrayed on-chip enzymatic colorimetric detection of d-lactate, a blood biomarker signifying the bacterial translocation from the intestine, with a limit of detection that is 1000-fold smaller than the clinical baseline, a 10 min assay time, high selectivity, and reasonably small variability across the entire arrays. The enzyme (Ez)/MoS2 optoelectronic biosensor unit consistently detected d-lactate in clinically important biofluids, such as saliva, urine, plasma, and serum of swine and humans with a wide detection range (10-3-103 μg/mL). Furthermore, the biosensor enabled us to show that high serum d-lactate levels are associated with the symptoms of systemic infection and inflammation. The lensless, optical waveguide-free device architecture should readily facilitate development of a monolithically integrated hand-held module for timely, cost-effective diagnosis of metabolic disorders in near-patient settings.

Clinical study of D-lactate and intestinal fatty acid binding protein in evaluating disease severity and prognosis of ICU patients: secondary analysis of a prospective, multicenter clinical study

To analyze the relationship between D-lactate, intestinal fatty acid binding protein (I-FABP) and the severity as well as the prognosis of patients in intensive care unit (ICU). Using a retrospective approach, the data derived from a prospective, randomized, single-blind, multicenter clinical study published earlier by our group were further analyzed to evaluate the effect of fat-modified enteral nutrition (EN) suspension on the intestinal barrier in ICU patients. In this study, a total of 141 patients were recruited from 7 ICUs in South China, and 15 healthy volunteers were included as healthy control group. Clinical data of patients were collected, including gender, age, disease severity related indicators such as acute physiology and chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), C-reactive protein (CRP) and initial ICU diagnosis, as well as prognostic indicators such as length of stay in ICU, length of stay in hospital and prognosis of patients at 28 days. To compare the difference of serum D-lactate and I-FABP between ICU patients and healthy control group on day 0 (the day before EN reached 500 mL) and day 5 (EN ≥ 2 092 kJ/d for 5 days). According to the hemodynamic and/or mechanical ventilation status on day 5 (compared with day 0), 141 patients were divided into the improvement group (101 cases) and the non-improvement group (40 cases), and the changes of D-lactate and I-FABP in the two groups were observed. Spearman correlation analysis was used to analyze the correlation between serum D-lactate, I-FABP and the severity of the disease, as well as the predictive value of dynamic changes of D-lactate and I-FABP on the prognosis of 28 days. Compared with the healthy volunteers, the serum D-lactate and I-FABP levels of ICU patients on day 0 were significantly increased [D-lactate (mg/L): 10.82 (3.31, 25.48) vs. 6.63 (1.54, 17.70), I-FABP (ng/L): 519.60 (159.06, 1 362.14) vs. 84.40 (30.78, 108.57), both P < 0.01], and D-lactate and I-FABP on day 5 were both decreased compared with the levels on day 0, but still higher than the healthy volunteers. I-FABP in the improvement group was significantly lower than that in the non-improvement group on day 0, and there was no significant difference in D-lactate levels between the two groups, D-lactate and I-FABP in both groups were significantly lower on day 5 than those on day 0, and D-lactate and I-FABP in the improvement group on day 5 were significantly lower than those in the non-improvement group [D-lactate (mg/L): 7.61 (1.71, 27.22) vs. 9.38 (2.09, 20.56), I-FABP (ng/L): 378.65 (152.56, 864.62) vs. 521.21 (205.93, 1 413.11), all P < 0.05]. Correlation analysis showed that D-lactate was significantly positively correlated with APACHE II score and SOFA score on day 0 and day 5 (R12 = 0.367, P < 0.001; R22 = 0.240, P = 0.012); I-FABP was significantly positively correlated with APACHE II score on day 0 (R2 = 0.264, P = 0.004); D-lactate on day 5 and I-FABP on day 0 and day 5 were significantly negatively correlated with prognosis on day 28 (R12 = -0.203, P = 0.022; R22 = -0.208, P = 0.023; R32 = -0.211, P = 0.021). The area under curve (AUC) analysis showed that D-lactate on day 5 and I-FABP on day 0 and day 5 had independent predictive value for 28-day prognosis, with AUC of 0.634, 0.638 and 0.652, P values of 0.023, 0.024 and 0.017, 95% confidence intervals (95%CI) of 0.533-0.734, 0.523-0.754 and 0.525-0.778, respectively. When the cut-off values were 7.71 mg/L, 593.55 ng/L and 468.10 ng/L, the sensitivity were 51.5%, 68.5% and 75.3%, and the specificity were 91.0%, 60.0% and 60.0%, respectively. Serum D-lactate and I-FABP were increased significantly and decreased with the improvement of the condition, and these two molecular biomarkers have certain value in predicting the prognosis of ICU patients.