The effects of long-term total parenteral nutrition on gut mucosal immunity in children with short bowel syndrome: a systematic review

Lycopene improves cisplatin induced hepatointestinal injury in rats by modulating the microbe-gut-liver axis

Cisplatin (CIS) is a commonly used antitumor drug in clinics, but its application is limited due to hepatotoxicity, nephrotoxicity and gastrointestinal toxicity. In recent years, a large number of studies have shown that the imbalance of intestinal flora is one of the important factors in the malignant development of diseases. Therefore, improving organ function by regulating intestinal flora may be an important strategy to prevent the side effects of chemotherapy drugs. Lycopene (LYC) is found in a wide range of red foods and has antioxidant, anti-inflammatory and immune-enhancing effects. So the purpose of this study was to explore its effect on hepatointestinal injury caused by chemotherapy drugs. The results of this study showed that CIS could significantly restore body weight, diet, water intake, and AST, ALT and other physiological and biochemical indexes of rats. HE staining, projective electron microscopy and TUNEL results showed that LYC alleviated morphological and ultrastructural damage of the liver and intestine. Then, ELISA results showed that LYC can reduce cell apoptosis by increasing the antioxidant capacity and reducing inflammatory response. Secondly, 16sRNA and metabolome results showed that LYC enriched beneficial bacteria (Firmicutes and Proteobacteria), reduced harmful bacteria (E. coli, etc.), enhanced metabolic pathway changes such as taurine and hypotaurine metabolism, and alleviated organ damage caused by CIS. Finally, network pharmacology, molecular docking and immunohistochemistry showed that LYC could reduce CIS induced hepatocyte inflammation and apoptosis by activating the PI3K/AKT pathway. In summary, LYC alleviates the toxic side effects of chemotherapy drugs by regulating the PI3K/AKT pathway and the intestinal microbiota-metabolite-liver axis.

Does Massive Bowel Resection in Newborns Affect Further Immunity in Children?

BACKGROUND

The massive resection of the small intestine leading to short bowel syndrome (SBS) deprives an organism of many immunocompetent cells concentrated in gut-associated lymphoid tissue, the largest immune organ in humans. We have aimed to access the influence of bowel resection on adaptive immunity in children, based on peripheral lymphocyte subsets and serum immunoglobulins.

METHODS

15 children who underwent bowel resection in the first months of their life and required further home parenteral nutrition were enrolled into the study. Based on flow cytometry, the following subsets of lymphocytes were evaluated: T, B, NK, CD4+, C8+, and activated T cells.

RESULTS

Statistically significant differences were found for the rates of lymphocytes B, T, CD8+, and NK cells. The absolute count of NK cells was lower in the SBS group than in the control group. Absolute counts of lymphocytes, lymphocytes B, T, CD4+, and percentages of lymphocytes CD4+, and activated T cells inversely correlated with age in SBS group.

CONCLUSIONS

Children with SBS do not present with clinical signs of immunodeficiency as well as deficits in peripheral lymphocyte subsets and serum immunoglobulins. The tendency of the lymphocyte subpopulations to decrease over time points out the necessity for longer follow- up.

Impaired FXR-CPT1a signaling contributes to parenteral nutrition-induced villus atrophy in short-bowel syndrome

Parenteral nutrition (PN)-induced villus atrophy is a major cause of intestinal failure (IF) for children suffering from short bowel syndrome (SBS), but the precise mechanism remains unclear. Herein, we report a pivotal role of farnesoid X receptor (FXR) signaling and fatty acid oxidation (FAO) in PN-induced villus atrophy. A total of 14 pediatric SBS patients receiving PN were enrolled in this study. Those patients with IF showed longer PN duration and significant intestinal villus atrophy, characterized by remarkably increased enterocyte apoptosis concomitant with impaired FXR signaling and decreased FAO genes including carnitine palmitoyltransferase 1a (CPT1a). Likewise, similar changes were found in an in vivo model of neonatal Bama piglets receiving 14-day PN, including villus atrophy and particularly disturbed FAO process responding to impaired FXR signaling. Finally, in order to consolidate the role of the FXR-CPT1a axis in modulating enterocyte apoptosis, patient-derived organoids (PDOs) were used as a mini-gut model in vitro. Consequently, pharmacological inhibition of FXR by tauro-β-muricholic acid (T-βMCA) evidently suppressed CPT1a expression leading to reduced mitochondrial FAO function and inducible apoptosis. In conclusion, impaired FXR/CPT1a axis and disturbed FAO may play a pivotal role in PN-induced villus atrophy, contributing to intestinal failure in SBS patients.

Novel Therapeutic Approaches for Mitigating Complications in Short Bowel Syndrome

Short bowel syndrome (SBS) is a particularly serious condition in which the small intestine does not absorb sufficient nutrients for biological needs, resulting in severe illness and potentially death if not treated. Given the important role of the gut in many signaling cascades throughout the body, SBS results in disruption of many pathways and imbalances in various hormones. Due to the inability to meet sufficient nutritional needs, an intravenous form of nutrition, total parental nutrition (TPN), is administered. However, TPN presents difficulties such as severe liver injury and altered signaling secondary to the continued lack of luminal contents. This manuscript aims to summarize relevant studies into the systemic effects of TPN on systems such as the gut-brain, gut-lung, and gut-liver axis, as well as present novel therapeutics currently under use or investigation as mitigation strategies for TPN induced injury.

Anti-Inflammatory Properties of Plasma from Children with Short Bowel Syndrome

Sepsis, resulting from a dysregulated host immune response to invading pathogens, is the leading cause of mortality in critically ill patients worldwide. Immunomodulatory treatment for sepsis is currently lacking. Children with short bowel syndrome (SBS) may present with less severe symptoms during gram-negative bacteremia. We, therefore, tested the hypothesis that plasma from children with SBS could confer protection against Escherichia coli sepsis. We showed that SBS plasma at 5% and 10% concentrations significantly (p < 0.05) inhibited the production of both TNF-α and IL-6 induced by either E. coli- or LPS-stimulated host cells when compared to plasma from healthy controls. Furthermore, mice treated intravenously with select plasma samples from SBS or healthy subjects had reduced proinflammatory cytokine levels in plasma and a significant survival advantage after E. coli infection. However, SBS plasma was not more protective than the plasma of healthy subjects, suggesting that children with SBS have other immunomodulatory mechanisms, in addition to neutralizing antibodies, to alleviate their symptoms during gram-negative sepsis.

Panax quinquefolium saponins protect against cisplatin evoked intestinal injury via ROS-mediated multiple mechanisms

BACKGROUND

Cisplatin is one of the most common chemotherapeutic drugs. Cisplatin-induced toxicity gives rise to gastrointestinal cell damage, subsequent diarrhea and vomiting, leading to the discontinuation of its clinical application in long-term cancer chemotherapy. Panax quinquefolium L., also known as American ginseng, has many pharmacological activities such as improving immunity, anti-tumor, anti-radiation and blood sugar lowering.

PURPOSE

Previously, our laboratory reported that American ginseng berry extract could alleviate chemotherapeutic agents-induced renal damage caused by cisplatin. Hence, this study further explored the protective effect of P. quinquefolium saponins (PQS) on cisplatin-induced intestinal injury in mice and the possible molecular mechanisms.

METHODS

Biochemical markers, levels of inflammatory factors, histopathological staining and western blotting were used to analyze intestinal injury based on various molecular mechanisms.

RESULTS

We demonstrated the destruction of the intestinal barrier caused by cisplatin exposure by detecting the activity of diamine oxidase (DAO) and the expression of tight junction proteins zonula occludens-1 (ZO-1) and occludin. Meanwhile, cisplatin exposure changed SOD and MDA levels in the small intestine, causing oxidative damage to the intestinal mucosa. The inflammation associated-intestinal damage was further explored by the measurement of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and analysis of nuclear factor-kappa B (NF-κB) inflammatory pathway protein expression. Moreover, apoptotic cells labeled with TUNEL staining-positive cells and activated caspase family proteins suggest that cisplatin induces intestinal apoptosis. Interestingly, PQS pretreatment significantly reversed these situations.

CONCLUSION

These evidences clearly suggest that PQS can alleviate cisplatin-induced intestinal damage by inhibiting oxidative stress, reducing the occurrence of inflammation and apoptosis, and improving intestinal barrier function.

Impaired Gut-Systemic Signaling Drives Total Parenteral Nutrition-Associated Injury

BACKGROUND

Total parenteral nutrition (TPN) provides all nutritional needs intravenously. Although lifesaving, enthusiasm is significantly tempered due to side effects of liver and gut injury, as well as lack of mechanistic understanding into drivers of TPN injury. We hypothesized that the state of luminal nutritional deprivation with TPN drives alterations in gut-systemic signaling, contributing to injury, and tested this hypothesis using our ambulatory TPN model.

METHODS

A total of 16 one-week-old piglets were allocated randomly to TPN (n = 8) or enteral nutrition (EN, n = 8) for 3 weeks. Liver, gut, and serum were analyzed. All tests were two-sided, with a significance level of 0.05.

RESULTS

TPN resulted in significant hyperbilirubinemia and cholestatic liver injury, p = 0.034. Hepatic inflammation (cluster of differentiation 3 (CD3) immunohistochemistry) was higher with TPN (p = 0.021). No significant differences in alanine aminotransferase (ALT) or bile ductular proliferation were noted. TPN resulted in reduction of muscularis mucosa thickness and marked gut atrophy. Median and interquartile range for gut mass was 0.46 (0.30-0.58) g/cm in EN, and 0.19 (0.11-0.29) g/cm in TPN (p = 0.024). Key gut-systemic signaling regulators, liver farnesoid X receptor (FXR; p = 0.021), liver constitutive androstane receptor (CAR; p = 0.014), gut FXR (p = 0.028), G-coupled bile acid receptor (TGR5) (p = 0.003), epidermal growth factor (EGF; p = 0.016), organic anion transporter (OAT; p = 0.028), Mitogen-activated protein kinases-1 (MAPK1) (p = 0.037), and sodium uptake transporter sodium glucose-linked transporter (SGLT-1; p = 0.010) were significantly downregulated in TPN animals, whereas liver cholesterol 7 alpha-hydroxylase (CyP7A1) was substantially higher with TPN (p = 0.011).

CONCLUSION

We report significant alterations in key hepatobiliary receptors driving gut-systemic signaling in a TPN piglet model. This presents a major advancement to our understanding of TPN-associated injury and suggests opportunities for strategic targeting of the gut-systemic axis, specifically, FXR, TGR5, and EGF in developing ameliorative strategies.

Nutrition in surgical patients: how soon is too soon?

PURPOSE OF REVIEW

Preoperative nutrition support has been extensively studied; however, data on the timing of postoperative nutrition initiation are scarce. The current review focuses on the importance of early nutritional support in surgical patients and their impact on outcomes.

RECENT FINDINGS

Early nutrition support during the postoperative course may be the most important step that can be taken toward preventing subsequent malnutrition-related complications. European Society for Parenteral and Enteral Nutrition guidelines recommends early nutrition to improve outcomes after surgery and accelerates the recovery. Moreover, nutritional support should be personalized, and disease process-based.

SUMMARY

Existing studies appear to focus mostly on abdominal and gastrointestinal surgery. Further prospective observational and randomized clinical trials across different surgical populations will aid surgeons to better understand how early feeds in either form can reduce morbidity, quality of life, and increase recovery rates.

Comparison of polyglycolic acid, polycaprolactone, and collagen as scaffolds for the production of tissue engineered intestine

Cell-seeded scaffolds play critical roles in the production of tissue engineered intestine (TEI), a potential strategy for the treatment of short bowel syndrome. The current study compares polyglycolic acid (PGA), polycaprolactone (PCL), and collagen as scaffolds for TEI production. Tubular PGA scaffolds were prepared from nonwoven BIOFELT^® . Tubular PCL scaffolds were fabricated by electrospinning. Tubular collagen scaffolds were prepared using CollaTape, a wound dressing material. Both PGA and collagen were coated with poly-l-lactic acid (PLLA) to improve scaffold mechanical properties. Pore size, porosity, microstructure, mechanical properties (suture retention strength and ultimate compressive force) were determined. The scaffolds were first seeded with crypt stem cells isolated from 1 to 3 day old rat pups and then implanted into the peritoneal cavity of nude rats. After 4 weeks of in vivo incubation, these cell-seeded scaffolds were harvested for assessment of the TEI produced. Of the three materials compared, PLLA coated tubular PGA scaffolds had the appropriate pore size, mechanical properties and degradation rate leading to the production of TEI with an architecture similar to that of native rat intestine. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 750-760, 2019.

Impact of bacterial translocation in calves with atresia coli

OBJECTIVE

To identify whether enteric bacteria pass into the mesenteric lymph nodes (MLNs) and peritoneal cavity in calves with atresia coli and to evaluate whether the presence of bacterial translocation (BT) has an impact on the success of surgical treatment.

DESIGN

Prospective clinical study.

ANIMALS

Twenty-six client-owned calves.

INTERVENTIONS

During laparotomy, swab samples were collected from the peritoneal cavity and MLNs using a sterile swab stick and were submitted for microbiological analysis.

MEASUREMENTS AND MAIN RESULTS

Bacterial cultures of swab samples revealed that 65% (n = 17) of the calves experienced BT. Of these, 14 calves experienced BT to the MLNs, 9 to the peritoneal cavity, and 5 to both regions. Of the bacteria isolated from the MLNs, 72% (n = 10) were Escherichia coli. Of the samples isolated from the peritoneal fluid, 33% (n = 3) contained E. coli and 33% (n = 3) contained E. coli + coagulase-negative Staphylococcus (CNS). In calves with BT that were discharged (n = 13) and without BT that were discharged (n = 7), the median survival was 30 days; these data were found to be similar in the 2 groups.

CONCLUSIONS

This study revealed that BT is observed in the majority of atresia coli cases. E. coli is more common in BT, and translocation occurs primarily through the lymphatic route. These results suggest that the presence of BT is closely related to the success of the operation for correction of atresia coli.

Alterations in intestinal microbiota relate to intestinal failure-associated liver disease and central line infections

BACKGROUND

The gut microbiota plays a vital role in modulating the metabolic and immune functions of the intestines. We aimed to analyze the dysbiosis of microbiota in infants with short bowel syndrome (SBS) with different complications.

PROCEDURE

We included 26 fecal samples from 18 infants with SBS during parenteral nutrition. The samples were categorized into three groups: asymptomatic, parenteral nutrition-associated liver disease (PNALD), and central line-associated bloodstream infection (CLABSI). Seven healthy infants were enrolled as controls. Fecal microbiota, secretory IgA, calprotectin, bile acids, and short chain fatty acids were detected.

RESULTS

The bacterial diversity of the Asymptomatic and Control Groups was significantly higher than that in the PNALD and CLABSI Groups. Proteobacteria was the most pronounced phylum in the PNALD and CLABSI Groups. Decreased acetate was observed in all SBS samples; however, fecal secretory IgA and calprotectin and the proportion of primary and secondary bile acids did not differ from those in healthy controls.

CONCLUSIONS

Marked alterations of the intestinal microbiota with decreased level of acetate were shown in SBS patients compared with healthy controls. Over-abundance of Proteobacteria (especially Enterobacteriaceae) was found in the samples from the PNALD and CLABSI Groups.

LEVEL OF EVIDENCE

Prognosis Study, Level I.

Dietary sodium propionate affects mucosal immune parameters, growth and appetite related genes expression: Insights from zebrafish model

Propionate is a short-chain fatty acid (SCFA) that improves physiological and pathophysiological properties. However, there is limited information available about the effects of SCFAs on mucosal immune parameters as well as growth and appetite related genes expression. The aim of the present study was to evaluate the effect of sodium propionate (SP) intake on the mucosal immune parameters, growth and appetite related genes expression using zebrafish (Danio rerio) as model organism. Zebrafish fed control or diet supplemented with different levels (0.5, 1 and 2%) of SP for 8weeks. At the end of feeding trial, the expression of the key genes related to growth and appetite (GH, IGF1, MYSTN and Ghrl) was evaluated. Also, mucosal immune parameters (Total Ig, lysozyme and protease activity) were studied in skin mucus of zebrafish. The results showed that dietary administration of SP significantly (P<0.05) up-regulated the expression of GH, IGF1 and down-regulated MYSTN gene. Also, feeding zebrafish with SP supplemented diet significantly increased appetite related gene expression (P<0.05) with a more pronounced effect in higher inclusion levels. Compared with control group, the expression of appetite related gene (Ghrl) was remarkably (P<0.05) higher in SP fed zebrafish. Also, elevated mucosal immune parameters was observed in zebrafish fed SP supplemented diet. The present results revealed beneficial effects of dietary SP on mucosal immune response and growth and appetite related genes expression. These results also highlighted the potential use of SP as additive in human diets.

Effect of early enteral nutrition on patients with digestive tract surgery: A meta-analysis of randomized controlled trials

Postoperative early enteral nutrition (EEN) is useful for the effective recovery of patients that have undergone surgery. However, the feasibility and efficacy of EEN in patients with digestive tract surgery remain inconclusive. In the present meta-analysis, the PubMed, EMBASE, Web of Science, The Cochrane Library, China National Knowledge Infrastructure and VIP databases were searched to identify controlled trials of patients with and without EEN following digestive tract surgery between October, 1966 and December, 2014. Methodological quality assessment was carried out for each of the included studies. For estimation of the analysis indexes, relative risk (RR) was used as the effect size of the the categorical variable, while the weighted mean difference (MD) was used as the effect size of the continuous variable. The meta-analysis was conducted using RevMan 5.2 software. Eleven randomized controlled trials involving 1,095 patients were included in the meta-analysis. The results revealed that, EEN in patients with digestive tract surgery was more effective in decreasing the incidence of infectious [RR=0.50, 95% confidence interval (CI): 0.38, 0.67; P<0.01] and non-infectious complications (RR=0.72, 95% CI: 0.43, 1.22; P<0.05) and shortening the length of first bowel action (MD=−4.10, 95% CI: −5.38, −2.82; P<0.05). It also had a significant influence on increasing the serum albumin (MD=2.87, 95% CI: 1.03, 4.71; P<0.05) and serum prealbumin (MD=0.04, 95% CI: 0.02, 0.05; P<0.05) levels. In conclusion, the results of the study have shown that EEN in patients with digestive tract surgery improved the nutritional status, reduced the risk of postoperative complications, shortened the length of hospital stay and promoted the functional recovery of the digestive system.

Effect of bowel resection on TLR signaling during intestinal adaptation in a rat model

BACKGROUND

Bacterial overgrowth is common complication of short bowel syndrome (SBS) and is a result of an impaired gut barrier function. Toll-like receptor 4 (TLR4) is crucial in maintaining intestinal epithelial homeostasis, participates in a vigorous signaling process and heightens inflammatory cytokine output. The objective of this study was to determine the effects of bowel resection on TLR4 signaling in intestinal mucosa in a rat model.

METHODS

Male Sprague-Dawley rats were randomly assigned to one of the two experimental groups of eight rats each: Sham rats underwent bowel transection and re-anastomosis and SBS rats underwent 75 % small bowel resection. Rats were killed on day 14. Bacterial translocation (BT) to mesenteric lymph nodes, liver, portal blood and peripheral blood was determined at the kill. The expression of TLR4, MyD88 and TRAF6 in the intestinal mucosa was determined using real-time PCR, Western blot and immunohistochemistry.

RESULTS

SBS rats demonstrated a 100 % BT to lymph nodes and to liver (Level I), 80 % translocation to portal blood (Level II) and 60 % translocation to peripheral blood (Level III) at day 7 as well as a 100 % BT to lymph nodes and liver, and 40 % translocation to peripheral blood at day 14. Microarray expression profiling demonstrated that most of the TLR signaling-related genes were up-regulated in resected rats compared to control animals. SBS rats showed a significant increase in TLR4 and TRAF6 mRNA in jejunum and ileum, TLR4 and MyD88 protein expression in jejunum and ileum, and a significant increase in the number of TLR4 and TRAF6 positive cells (immunohistochemistry) compared to sham animals.

CONCLUSIONS

In a rat model of SBS, elevated intestinal BT is associated with a stimulated TLR4 signaling.

Impact of the feeding route on gut mucosal immunity

PURPOSE OF REVIEW

Enteral nutrition is recommended as a standard nutritional therapy in clinical settings. The rationale behind enteral nutrition may be decreased infectious morbidities compared with parenteral nutrition. However, the mechanism may not be well understood.

RECENT FINDINGS

Animal studies have revealed that enteral nutrition, compared with parenteral nutrition, preserves the gut-associated lymphoid tissue mass and function with well controlled gut cytokine milieu and intracellular signaling pathway, leading to the maintenance of intestinal and extraintestinal acquired mucosal immunity. Moreover, enteral nutrition can enhance the gut innate immunity by increasing the antimicrobial peptides, such as secretory phospholipase A2. More importantly, a recent clinical study demonstrated preoperative parenteral nutrition without enteral nutrition to decrease the number of T cells, IgA-producing cells, and mature dendritic cells in human terminal ileum, which are consistent with the data obtained from animal studies. Investigation of the mechanism has given us some surrogates of enteral nutrition during parenteral nutrition, such as glutamine, butyric acid, cytokines, and other mediators. However, to date, no surrogates can restore parenteral-nutrition-induced impairment of host defense completely.

SUMMARY

Because enteral nutrition is a practical way to preserve gut immunity, clinicians should make any efforts to shorten the period of enteral nutrition absence and increase the dose according to the degree of tolerance.

Regulation of intestinal epithelial permeability by tight junctions

The gastrointestinal epithelium forms the boundary between the body and external environment. It effectively provides a selective permeable barrier that limits the permeation of luminal noxious molecules, such as pathogens, toxins, and antigens, while allowing the appropriate absorption of nutrients and water. This selective permeable barrier is achieved by intercellular tight junction (TJ) structures, which regulate paracellular permeability. Disruption of the intestinal TJ barrier, followed by permeation of luminal noxious molecules, induces a perturbation of the mucosal immune system and inflammation, and can act as a trigger for the development of intestinal and systemic diseases. In this context, much effort has been taken to understand the roles of extracellular factors, including cytokines, pathogens, and food factors, for the regulation of the intestinal TJ barrier. Here, I discuss the regulation of the intestinal TJ barrier together with its implications for the pathogenesis of diseases.

Recent progress in histochemistry and cell biology

Studies published in Histochemistry and Cell Biology in the year 2011 represent once more a manifest of established and newly sophisticated techniques being exploited to put tissue- and cell type-specific molecules into a functional context. The review is therefore the Histochemistry and Cell Biology's yearly intention to provide interested readers appropriate summaries of investigations touching the areas of tissue biology, developmental biology, the biology of the immune system, stem cell research, the biology of subcellular compartments, in order to put the message of such studies into natural scientific-/human- and also pathological-relevant correlations.

Insulin-like growth factor 1: common mediator of multiple enterotrophic hormones and growth factors

PURPOSE OF REVIEW

To summarize the recent evidence that insulin-like growth factor 1 (IGF1) mediates growth effects of multiple trophic factors and discuss clinical relevance.

RECENT FINDINGS

Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogs in short bowel syndrome and Crohn's disease. This review highlights the evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn's disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that suppressor of cytokine signaling protein induction by GH or GLP2 in normal or inflamed intestine may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis, is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed.

SUMMARY

IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed.

Effects of probiotics on experimental short-bowel syndrome

BACKGROUND

This study was performed to analyze the potential benefits of probiotics on experimental short-bowel syndrome (SBS).

METHODS

Forty-eight male Wistar-Albino rats were used in the study. The animals were divided into 6 groups as follows: control, rats that received probiotics, rats that underwent intestinal transection and anastomosis, rats that underwent anastomosis and received probiotics, rats that underwent 75% intestinal resection, and rats that underwent 75% intestinal resection plus received probiotics. Body weight monitoring, intestinal bowel diameter, villus length and crypt depth measurements, goblet cell count, mitosis, and immunohistochemical evaluation were used for the assessment of intestinal proliferation ability.

RESULTS

Statistical analysis showed a significant difference in villus length, crypt depth, goblet cell count in villus and crypt, mitosis, and immunohistochemical evaluation in the jejunum when the SBS group was compared with the SBS group that received probiotics. There was no significant difference in these parameters in ileum.

CONCLUSIONS

This trial clearly has shown that probiotics had a positive impact on jejunum in the experimental SBS.

Potential of cell therapy to treat pediatric motility disorders

Gut motility disorders represent a significant challenge in clinical management with current palliative approaches failing to overcome disease and treatment-related morbidity. The recent progress with stem cells to restore missing or defective elements of the gut neuromusculature offers new hope for potential cure. Focusing on enteric neuropathies such as Hirschsprung's disease, the review discusses the progress that has been made in the sourcing of putative stem cells and the studies into their biology and therapeutic potential. It also explores the practical challenges that must be overcome before stem cell-based therapies can be applied in the clinical arena. Although many obstacles remain, the speed of advancement of the enteric stem cell field suggests that such therapies are on the horizon.

Effect of lactulose on bacterial translocation and intestinal adaptation in a rat model of short bowel syndrome

BACKGROUND

It is frequently assumed that dietary nondigestible carbohydrates improve host resistance to intestinal infections by stimulating proliferation of the protective gut microflora. Therefore, the aim of this study was to define the effect of lactulose, a nondigestible carbohydrate, on bacterial translocation and intestinal adaptation in a rat model of short bowel syndrome (SBS).

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into 3 experimental groups. Sham rats underwent bowel transection, SBS rats underwent 75% small bowel resection, and SBS-LAC rats underwent bowel resection and were treated with oral lactulose given in drinking water at a dose of 1.5 g x kg(-1) x day(-1) from the 3rd to the 15th postoperative day. Bacterial translocation (to mesenteric lymph nodes, liver, and portal and peripheral blood) and parameters of intestinal adaptation were determined on day 15.

RESULTS

Treatment with lactulose did not change bacterial translocation, but decreased ileal mucosal weight (20%; P < 0.05), ileal mucosal DNA (2-fold decrease; P < 0.05) and protein (26%; P < 0.05), villus height in jejunum (21%; P < 0.05) and crypt depth in ileum (17%; P < 0.05), proliferation rates in jejunum (18%; P < 0.05) and ileum (15%; P < 0.05), and apoptotic index in jejunum (40%; P < 0.05) and ileum (36%; P < 0.05) compared with SBS animals. Bax expression was upregulated in SBS rats compared with control animals, but decreased following treatment with lactulose.

CONCLUSIONS

In a rat model of SBS, oral lactulose does not improve bacterial translocation from the intestine, but inhibits intestinal adaptation.

Insulin receptor substrate-1 deficiency promotes apoptosis in the putative intestinal crypt stem cell region, limits Apcmin/+ tumors, and regulates Sox9

Reduced apoptosis of crypt stem/progenitor cells and elevated insulin and IGFs are linked to colon cancer risk. Insulin receptor substrate-1 (IRS-1) mediates the actions of insulin, IGF-I, and IGF-II, but the role of endogenous IRS-1 in crypt apoptosis and cancer is undefined. Using IRS-1(-/-), IRS-1(+/-), and IRS-1(+/+) mice, we tested the hypothesis that reduced IRS-1 expression increases apoptosis of intestinal crypt cells and protects against Apc(min/+) (Min)/beta-catenin-driven intestinal tumors. Expression of Sox9, a transcriptional target of Tcf/beta-catenin and putative biomarker of crypt stem cells, was assessed in intestine of different IRS-1 genotypes and cell lines. Irradiation-induced apoptosis was significantly increased in the crypts and crypt stem cell region of IRS-1-deficient mice. Tumor load was significantly reduced by 31.2 +/- 14.6% in IRS-1(+/-)/Min and by 64.1 +/- 7.6% in IRS-1(-/-)/Min mice, with more prominent reductions in tumor number than size. Compared with IRS-1(+/+)/Min, IRS-1(-/-)/Min mice had fewer Sox9-positive cells in intestinal crypts and reduced Sox9 mRNA in intestine. IRS-1 overexpression increased Sox9 expression in an intestinal epithelial cell line. We conclude that even small reductions in endogenous IRS-1 increase apoptosis of crypt stem or progenitor cells, protect against beta-catenin-driven intestinal tumors, and reduce Sox9, a Tcf/beta-catenin target and putative stem/progenitor cell biomarker.

Oral antibiotics attenuate bowel segment reversal-induced systemic inflammatory response and body weight loss in massively bowel-resected rats

BACKGROUND

Using a massively bowel-resected rat model, our previous study demonstrated that small bowel segment reversal stimulates jejunal hyperplasia but may also increase the possibility of bacterial translocation and the elevation of circulating white blood cells and serum interleukin-6 that may reduce the whole-body anabolism. The aim of this study is to investigate whether oral antibiotics might attenuate the inflammatory responses and might therefore facilitate the beneficial effects of bowel segment reversal.

METHODS

Male Wistar rats (approximately 270 g) underwent a 70% small bowel resection with (REV group) or without (CON group) a 3-cm small bowel segment reversal, or underwent a sham operation (SHAM group). After surgeries, half of the animals in the REV group were given oral clindamycin plus amoxicillin (50 plus 50 mg/kg/d, ANT group) for 3 weeks.

RESULTS

Oral antibiotics administration significantly attenuated the decreases in feeding efficiency (g of body weight/100 kcal diet) and increases in the circulation of white blood cells, serum nitric oxide, and interleukin-6 (1-way ANOVA, p < .05), which are associated with bowel segment reversal. In addition, antibiotics significantly increased serum concentrations of insulin-like growth factor-I, significantly decreased the total numbers of bacteria in the intestine, and tended to reduce the extent of jejunal hyperplasia in rats with bowel segment reversal.

CONCLUSIONS

Our results suggest that oral antibiotics may be used as an adjuvant to attenuate the inflammatory responses and to enhance the anabolic responses in massively bowel-resected patients with bowel segment reversal.

Future horizons in the treatment of enteric neuropathies

Enteric neuropathies comprise a vast and disparate array of congenital and acquired disorders of the enteric nervous system (ENS), reflecting both the complexity of its neuronal composition and the many interactions that modulate its function. Although present therapeutic strategies, largely limited to surgery and the provision of artificial nutrition, have transformed the early survival and life of sufferers, levels of morbidity and mortality remain unacceptably high. This highlights the need to develop new treatments for enteric neuropathies. In the last decade, the tremendous advances in molecular biology and genetics have significantly enhanced our understanding of ENS development and function. Coupled with equivalent progress in the fields of pharmacology and stem-cell biology, this has led to the identification of novel tools and targets for therapy, which either aim to optimise the function of the intrinsic ENS or replace/replenish components of an inadequate or dysfunctional ENS. This article reviews current work on a number of these interventions with a particular focus on the use of ENS stem cells as potential therapeutic tools for enteric neuropathies.

Effect of probiotics on intestinal regrowth and bacterial translocation after massive small bowel resection in a rat

BACKGROUND/PURPOSE

Because of their ability to inhibit intestinal bacterial overgrowth, probiotics (PROs) have been advocated for the treatment of patients with short bowel syndrome (SBS). This study was conducted to determine the effect of PROs on bacterial translocation and intestinal regrowth after massive small bowel resection in a rat.

METHODS

Male Sprague-Dawley rats were divided into 3 experimental groups: sham rats underwent bowel transection and reanastomosis, SBS rats underwent 75% small bowel resection, and SBS-PRO rats underwent bowel resection and were treated with a PRO given in drinking water from day 4 through 14. Intestinal structural changes (bowel circumference, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, enterocyte proliferation and enterocyte apoptosis) and bacterial translocation (BT) to mesenteric lymph nodes, liver, portal blood, and peripheral blood were determined on day 15 after operation.

RESULTS

Sham rats exhibited a 20% BT to the mesenteric lymph nodes (level I), liver (level II), and blood (level III). Short bowel syndrome rats demonstrated a 100% BT to lymph nodes (level I) and liver (level II) and 40% translocation to peripheral blood (level III). Treatment with PROs resulted in a significant decrease in BT to all 3 target organs and decreased enterocyte apoptosis compared with SBS-untreated animals. Short bowel syndrome rats showed a significant increase (vs sham) in jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth. Short bowel syndrome rats also had a greater proliferation index and apoptotic index in both jejunum and ileum compared with sham animals. SBS-PRO rats showed a significant increase (vs SBS rats) in crypt depth in ileum and a mild decrease in apoptotic index in jejunum and ileum, compared with SBS-untreated animals.

CONCLUSIONS

In a rat model of SBS, PROs decrease BT through mechanisms which maybe dependent on intestinal mucosal integrity.

Treatment Outcomes of Necrotizing Enterocolitis for Preterm Infants

Necrotizing enterocolitis (NEC) is one of the most common life-threatening gastrointestinal emergencies for the preterm infant. The survival rate for preterm infants after NEC has improved over the past two decades, but complications arising from medical and surgical intervention have produced many long term problems. Documented consequences of NEC include feeding intolerance and physical, developmental and cognitive problems. Bedside nurses are well positioned to detect early changes in the infant that may enable early treatment and reduce long-term complications.

Immune modulation by parenteral lipid emulsions

Total parenteral nutrition is the final option for nutritional support of patients with severe intestinal failure. Lipid emulsions constitute the main source of fuel calories and fatty acids (FAs) in parenteral nutrition formulations. However, adverse effects on patient outcomes have been attributed to the use of lipids, mostly in relation to impaired immune defenses and altered inflammatory responses. Over the years, this issue has remained in the limelight, also because technical advances have provided no safeguard against the most daunting problems, ie, infectious complications. Nevertheless, numerous investigations have failed to produce a clear picture of the immunologic characteristics of the most commonly used soybean oil-derived lipid emulsions, although their high content of n-6 polyunsaturated FAs (PUFAs) has been considered a drawback because of their proinflammatory potential. This concern initiated the development of emulsions in which part of the n-6 FA component is replaced by less bioactive FAs, such as coconut oil (rich in medium-chain saturated FAs) or olive oil (rich in the n-9 monounsaturated FA oleic acid). Another approach has been to use fish oil (rich in n-3 PUFA), the FAs of which have biological activities different from those of n-6 PUFAs. Recent studies on the modulation of host defenses and inflammation by fish-oil emulsions have yielded consistent data, which indicate that these emulsions may provide a tool to beneficially alter the course of immune-mediated conditions. Although most of these lipids have not yet become available on the US market, this review synthesizes available information on immunologic characteristics of the different lipids that currently can be applied via parenteral nutrition support.

Nutritional management of infants with short bowel syndrome

The prevalence of short bowel syndrome appears to be increasing because of more aggressive surgical and medical approaches to the management of neonatal intraabdominal catastrophies. Hence, a large cohort of neonates with intestinal failure occupies neonatal intensive care units, requiring chronic total parenteral nutrition (TPN) in hopes that the residual bowel will adapt, thereby permitting weaning of TPN. Alternatively, when there is no hope for adaptation, these infants are maintained on TPN in hopes that they will grow to a size and state of general health satisfactory for either isolated intestinal transplant when liver function is preserved or combined liver-intestinal transplantation when the liver is irreparably damaged. Thus, it is imperative to provide enough parenteral nutrition to facilitate growth while minimizing TPN constituents predisposing to liver damage. Liver disease associated with intestinal failure (IFALD) seems to occur due to a variety of host factors combined with deleterious components of TPN. Host factors include an immature bile secretory mechanism, bile stasis due to fasting, and repeated septic episodes resulting in endotoxemia. Many constituents of TPN are associated with liver damage. Excessive glucose may result in fatty liver and/or hepatic fibrosis, excessive protein may lead to reduced bile flow, and phytosterols present in intravenous lipid may produce direct oxidant damage to the liver or may impede cholesterol synthesis and subsequent bile acid synthesis. Parenteral strategies employed to minimize TPN damage include reducing glucose infusion rates, reducing parenteral protein load, and reducing parenteral lipid load. Furthermore, preliminary studies suggest that fish oil-based lipid solutions may have a salutary effect on IFALD. Ultimately, provision of enteral nutrition is imperative for preventing or reversing IFALD as well as facilitating bowel adaptation. While studies of trophic hormones are ongoing, the most reliable current method to facilitate adaptation is to provide enteral nutrition. Continuous enteral feeding remains the mainstay of enteral nutrition support.

New growth factor therapies aimed at improving intestinal adaptation in short bowel syndrome

Short bowel syndrome (SBS) is used to describe a condition of malabsorption and malnutrition resulting from the loss of absorptive area following massive small bowel resection. The key to improved clinical outcome after massive small bowel resection is the ability of the residual bowel to adapt. Although still in experimental stages, a major goal in the management of SBS may be the augmented use of growth factors to promote increased adaptation. A number of growth factors have been implicated in promoting the adaptation process. The best-described growth factors are reviewed: glucagon-like peptide-2 (GLP-2), epidermal growth factor (EGF), and growth hormone (GH). This article reviews the ability of recombinant GLP-2, EGF and GH to modulate structural and functional aspects of intestinal adaptation following small bowel resection. Although these growth factors have shown promise, small sample size, inconsistent measurement parameters and uncontrolled study designs have hampered the acquisition of strong data advocating the use of growth factor treatment for SBS. Multicenter trials using well-defined outcome measures to assess clinical efficacy are needed to direct the clinical indications, timing and duration of therapy and assess potential risks associated with growth factor therapies.

An update on parenteral lipids and immune function: only smoke, or is there any fire?

PURPOSE OF REVIEW

This paper synthesizes information from recent studies on the modulation of immune responses by lipid emulsions that are applied as part of parenteral nutrition. This issue is especially relevant in light of the high rate of infectious complications and disturbed inflammatory responses in patients receiving this form of nutritional support.

RECENT FINDINGS

Studies reporting on novel emulsions based on olive and fish oils, structured lipids or mixed-type emulsions in which various lipid species replace conventional long-chain triglycerides indicate that these lipids are generally well tolerated. While long-chain triglycerides may promote inflammation due to conversion of n-6 polyunsaturated fatty acids into arachidonic acid-derived eicosanoids, structured lipids and olive oil emulsions appear more immune-neutral. Leukocyte-activating effects of medium-chain triglycerides in experimental studies await further characterization in vivo. A body of evidence shows that immune modulation by fish oil emulsions is essentially anti-inflammatory in nature. This is in line with the observation that n-3 polyunsaturated fatty acids in fish oil replace arachidonic acid in cell membranes as an eicosanoid substrate, resulting in a decreased production of pro-inflammatory mediators. Importantly, recent investigations indicate beneficial effects of parenteral fish oil on relevant clinical outcome measures.

SUMMARY

The characteristics of, and mechanisms behind, the effects of various parenteral lipids on immune function are becoming increasingly well understood. The practical relevance of many of these findings is not immediately clear, however, and will have to be substantiated in adequately powered trials before we can translate these findings into a tailored approach for specific clinical situations.