Qualitative and quantitative comparison of gut bacterial colonization in enterally and parenterally fed neonatal pigs

Total parenteral nutrition (TPN) has been associated with mucosal atrophy, impaired gut barrier function, and translocation of luminal bacteria with resultant sepsis in preterm human infants. Currently, we examined the effects of enteral (ENT) or TPN treatments on translocation events in neonatal pigs and on colonization and composition of microbiota in the neonatal gut. Newborn, colostrum-deprived pigs (<24 hours old) were fitted with intravenous catheters and were fed either ENT (n = 13) or TPN (n = 13) for 7 days. After 7 days of treatment, pigs were euthanized and samples were collected for bacterial culture from the blood, intestinal tract and organs. ENT pigs had increased numbers of bacterial genera isolated, higher concentrations of bacteria (CFU/g), and increased colonization of all segments of the intestinal tract compared to the TPN pigs. Translocation of bacteria from the intestinal tract to tissues or blood was similar (8 of 13) for both groups. The ENT group had 1/13 positive for Clostridium difficile toxin A whereas the TPN group had 5/13. We concluded that ENT favored increased bacterial concentrations comprised of more speciation in the gastrointestinal tract compared to TPN, and that TPN-treated piglets were at higher risk of colonization by toxin-expressing strains of C. difficile.     

Glucagon-like peptide-2 induces intestinal adaptation in parenterally fed rats with short bowel syndrome

Glucagon-like peptide-2 (GLP-2) is an intestinal trophic enteroendocrine peptide that is associated with intestinal adaptation following resection. Herein, we investigate the effects of GLP-2 in a total parenteral nutrition (TPN)-supported model of experimental short bowel syndrome. Juvenile Sprague-Dawley rats underwent a 90% small intestinal resection and jugular catheter insertion. Rats were randomized to three groups: enteral diet and intravenous saline infusion, TPN only, or TPN + 10 microg.kg(-1).h(-1) GLP-2. Nutritional maintenance was isocaloric and isonitrogenous. After 7 days, intestinal permeability was assessed by quantifying the urinary recovery of gavaged carbohydrate probes. The following day, animals were euthanized, and intestinal tissue was processed for morphological and crypt cell proliferation (CCP) analysis, apoptosis (caspase-3), and expression of SGLT-1 and GLUT-5 transport proteins. TPN plus GLP-2 treatment resulted in increased bowel and body weight, villus height, intestinal mucosal surface area, CCP, and reduced intestinal permeability compared with the TPN alone animals (P < 0.05). GLP-2 treatment induced increases in serum GLP-2 levels and intestinal SGLT-1 expression (P < 0.01) compared with either TPN or enteral groups. No differences were seen in the villus apoptotic index between resection groups. Enterally fed resected animals had a significant decrease in crypt apoptotic indexes compared with nontreated animals. This study demonstrates that GLP-2 alone, without enteral feeding, stimulates indexes of intestinal adaptation. Secondly, villus hypertrophy associated with adaptation was predominantly due to an increase in CCP and not to changes in apoptotic rates. Further studies are warranted to establish the mechanisms of action and therapeutic potential of GLP-2.     

Enteral nutrients potentiate glucagon-like peptide-2 action and reduce dependence on parenteral nutrition in a rat model of human intestinal failure

Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived gut hormone that shows promise for the treatment of short bowel syndrome (SBS). Our objective was to investigate how combination GLP-2 + enteral nutrients (EN) affects intestinal adaption in a rat model that mimics severe human SBS and requires parenteral nutrition (PN). Male Sprague-Dawley rats were assigned to one of five groups and maintained with PN for 18 days: total parenteral nutrition (TPN) alone, TPN + GLP-2 (100 μg·kg(-1)·day(-1)), PN + EN + GLP-2(7 days), PN + EN + GLP-2(18 days), and a nonsurgical oral reference group. Animals underwent massive distal bowel resection followed by jejunocolic anastomosis and placement of jugular catheters. Starting on postoperative day 4, rats in the EN groups were allowed ad libitum access to EN. Groups provided PN + EN + GLP-2 had their rate of PN reduced by 0.25 ml/day starting on postoperative day 6. Groups provided PN + EN + GLP-2 demonstrated significantly greater body weight gain with similar energy intake and a safe 80% reduction in PN compared with TPN ± GLP-2. Groups provided PN + EN + GLP-2 for 7 or 18 days showed similar body weight gain, residual jejunal length, and digestive capacity. Groups provided PN + EN + GLP-2 showed increased jejunal GLP-2 receptor (GLP-2R), insulin-like growth factor-I (IGF-I), and IGF-binding protein-5 (IGFBP-5) expression. Treatment with TPN + GLP-2 demonstrated increased jejunal expression of epidermal growth factor. Cessation of GLP-2 after 7 days with continued EN sustained the majority of intestinal adaption and significantly increased expression of colonic proglucagon compared with PN + EN + GLP-2 for 18 days, and increased plasma GLP-2 concentrations compared with TPN alone. In summary, EN potentiate the intestinotrophic actions of GLP-2 by improving body weight gain allowing for a safe 80% reduction in PN with increased jejunal expression of GLP-2R, IGF-I, and IGFBP-5 following distal bowel resection in the rat.     

R-Spondin1 enhances wnt signaling and decreases weight loss in short bowel syndrome zebrafish

BackgroundR-spondins, including R-spondin 1 (RSPO1), are a family of Wnt ligands that help to activate the canonical Wnt/β-catenin pathway, which is critical for intestinal epithelial cell proliferation and maintenance of intestinal stem cells. This proliferation underpins the epithelial expansion, or intestinal adaptation (IA), that occurs following massive bowel resection and short bowel syndrome (SBS). The purpose of this study was to identify if recombinant human RSPO1 (rhRSPO1) could be serially administered to SBS zebrafish to enhance cellular proliferation and IA.MethodsAdult male zebrafish were assigned to four groups: sham + PBS, SBS + PBS, sham + rhRSPO1, and SBS + rhRSPO1. Sham fish had a laparotomy alone. SBS fish had a laparotomy with distal intestinal ligation and creation of a proximal stoma. Fish were weighed at initial surgery and then weekly. rhRSPO1 was administered post-operatively following either a one- or two-week dosing schedule with either 3 or 5 intraperitoneal injections, respectively. Fish were harvested at 7 or 14 days with intestinal segments collected for analysis.ResultsRepeated intraperitoneal injection of rhRSPO1 was feasible and well tolerated. At 7 days, intestinal epithelial proliferation was increased by rhRSPO1. At 14 days, SBS + rhRSPO1 fish lost significantly less weight than SBS + PBS fish. Measurements of intestinal surface area were not increased by rhRSPO1 administration but immunofluorescent staining for β-catenin and gene expression for cyclin D1 was increased.ConclusionsIntraperitoneal injection of rhRSPO1 decreased weight loss in SBS zebrafish with increased β-catenin + cells and cyclin D1 expression at 14 days, indicating improved weight maintenance might result from increased activation of the canonical Wnt pathway.     

Modulation of bacterial translocation in mice mediated through lactose and human milk oligosaccharides

Massive resection of the small intestine in infants is imposed to the regulation of several intestinal pathological situations, as intestinal adaptation cannot be relied upon. Many nutritional disturbances are occurring following surgery procedure. In this vein, long-term parenteral feeding is adopt to improve prognosis not always successfully. Clostridia and more specifically Clostridium perfringens, are suspected to participate in the physiopathology of the rising situation. In order to investigate the effect of lactose and human milk neutral oligosaccharides (HMNOs) on Clostridia, germfree mice were inoculated either with enterotoxigenic C.perfringens strain isolated from a patient with NEC, or with a human microbiota harboring C.clostridioforme group(HF). In this vein, different doses of lactose were administrated during 2 weeks in adult mice on an attempt to evaluate the lactase activity. Intake of lactose (70 g/L) and HMNOs (7 g/L) in C.perfringens monoassociated mice induced mortality within a week. In HF mice, no mortality was observed. An increase in Clostridia occurrence was observed in the median ileum after intake of 7 g lactose (p = 0.017). Higher clostridial numbers occurred in caecum following intake of 70 g lactose (p < 0.05) and HMNOs (p < 0.025). Bifidobacteria were found increased from distal ileum to colon following 70 g of lactose intake, whereas they decreased in the caecum of mice drinking lower lactose concentrations. Finally, bacteremia was more frequent in 70 g lactose/L mice (p < 0.02), whereas at lower doses of lactose bifidobacterial translocation was observed.As a result, human milk oligosaccharides could favor clostridial population when reaching the lower intestine. The shortness of the small intestine in infants underwent massive intestinal resection seems to be associated to an incomplete breakdown of lactose. Enteral feeds formulas deprived in lactose would be more suitable in enteral feeding of infants.     

Differential jejunal and colonic adaptation due to resection and IGF-I in parenterally fed rats

Patients with severe short-bowel syndrome (SBS) often require long-term total parenteral nutrition (TPN) to maintain their nutritional status because of limited intestinal adaptation. Growth factors, including insulin-like growth factor I (IGF-I), are under investigation to promote intestinal adaptation and tolerance to oral feeding. We investigated structural and functional adaptation of the jejunum and colon in four groups of rats maintained with TPN for 7 days after a 60% jejunoileal resection and cecectomy or sham surgery and treatment with IGF-I or vehicle. Resection alone did not stimulate jejunal growth. IGF-I significantly increased jejunal mucosal mass, enterocyte proliferation, and migration rates. IGF-I decreased jejunal sucrase specific activity and reduced active ion transport and ionic permeability; resection alone had no effect. In contrast, resection significantly increased colonic mass and crypt depth but had no effect on active ion transport or ionic permeability. IGF-I had minimal effects on colonic structure. IGF-I but not resection stimulates jejunal adaptation, whereas resection but not IGF-I stimulates colonic growth in rats subjected to a model for human SBS. IGF-I treatment may improve intestinal adaptation in humans with SBS.     

A single enteral feed prior to the commencement of parenteral nutrition ameliorates the incidence of steatosis in parenterally fed neonatal piglets

Total parenteral nutrition (TPN) in neonates is associated with liver dysfunction. The initial post-partum enteral feed plays a key role in establishing post-partum metabolic regulation. Therefore absence of enteral nutrition, in neonates commencing TPN immediately post-partum, may induce metabolic abnormalities driving liver dysfunction associated with TPN. To study the effect of a single enteral feed prior to commencing TPN on the aetiology of liver dysfunction in neonatal piglets maintained on TPN for 7 days. Piglets were delivered by caesarean section on day 112 of gestation. They were divided into two groups, receiving either no enteral intake (N) or a single 10 ml feed of sows milk (EF) before being fed by TPN for 7 days, after which tissue samples were taken. Hepatic lipid metabolism and enzyme activity were assessed coupled with metabolomic profiles. Piglets receiving no enteral nutrition accumulated more hepatic lipid (N 7.58 ± 0.84, EF 5.21 ± 0.30 g lipid·100 g of liver⁻¹, P = 0.013). Hepatic PEPCK activity was increased in EF piglets (N 8.59 ± 0.95, EF 10.57 ± 1.38 U·mg protein⁻¹, P = 0.024), alongside reduced hepatic lactate and key amino acid concentrations and increased muscle glucose. A single enteral feed immediately after birth alters hepatic metabolism, possibly by switching from lipid biosynthesis to gluconeogenesis, thereby reducing hepatic steatosis that occurs in response to TPN.     

The role of activated NLRP3 inflammatory body in acute kidney injury in rats caused by sepsis and NLRP3-TXNIP signaling pathway

ObjectiveThe model of acute renal injury (AKI) induced by sepsis in rats was established by abdominal resection through surgical suture. The activation mechanism of nod-like receptor with pyrin domain containing 3 (NLRP3) inflammatory corpuscle in AKI induced by sepsis was analyzed.MethodsHere, 60 male rats were selected and divided into two groups, including sham-operated group (NO-OPs group, n = 15) and sepsis group (CELP group, n = 45). In order to examine each index of CELP group, four time points (10, 20, 30, and 40 h) were set as control. In NO-OPs group, only abdominal resection through surgical suture was carried out. The expression levels of NLRP3, apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), caspase-1, and the expression level of NLRP3-TXNIP signaling pathway were measured by immunohistochemistry, Western blotting, immunoprecipitation, and mito-TEMPO (a mitochondria-targeted antioxidant) 40 h after operation and 10, 20, 30, and 40 h post-operation in CELP group. Herein, 40 h post-operation in NO-OPs group and 10, 20, 30, and 40 h post-operation in CELP group, peripheral blood samples were collected.ResultsCompared with NO-OPs group, the levels of serum creatinine (Scr) and blood urea nitrogen (BUN) in CELP group were increased (P < 0.05). Compared with NO-OPs group, the expression levels of interleukin-1β (IL-1β), NLRP3, ASC, and caspase-1 in CELP group were increased (P < 0.05). The expression level of TXNIP in renal tubular epithelial cells in rats was up-regulated. There was a positive correlation between TXNIP and NLRP3. The binding of NLRP3-TXNIP signaling pathway could be inhibited by siRNA transfection or mito-TMPO, and the activity of NLRP3 inflammatory bodies could be inhibited as well.ConclusionActivation of NLRP3 inflammatory corpuscles could promote AKI induced by sepsis. Simultaneously, renal injury may lead to the production of mitochondrial reactive oxygen species (mROS), which may induce the binding of TXNIP to NLRP3.     

Role of luminal nutrients and endogenous GLP-2 in intestinal adaptation to mid-small bowel resection

To elucidate the role of luminal nutrients and glucagon-like peptide-2 (GLP-2) in intestinal adaptation, rats were subjected to 70% midjejunoileal resection or ileal transection and were maintained with total parenteral nutrition (TPN) or oral feeding. TPN rats showed small bowel mucosal hyperplasia at 8 h through 7 days after resection, demonstrating that exogenous luminal nutrients are not essential for resection-induced adaptation when residual ileum and colon are present. Increased enterocyte proliferation was a stronger determinant of resection-induced mucosal growth in orally fed animals, whereas decreased apoptosis showed a greater effect in TPN animals. Resection induced significant transient increases in plasma bioactive GLP-2 during TPN, whereas resection induced sustained increases in plasma GLP-2 during oral feeding. Resection-induced adaptive growth in TPN and orally fed rats was associated with a significant positive correlation between increases in plasma bioactive GLP-2 and proglucagon mRNA expression in the colon of TPN rats and ileum of orally fed rats. These data support a significant role for endogenous GLP-2 in the adaptive response to mid-small bowel resection in both TPN and orally fed rats.     

Vagal afferents are essential for maximal resection-induced intestinal adaptive growth in orally fed rats

Small bowel resection stimulates intestinal adaptive growth by a neuroendocrine process thought to involve both sympathetic and parasympathetic innervation and enterotrophic hormones such as glucagon-like peptide-2 (GLP-2). We investigated whether capsaicin-sensitive vagal afferent neurons are essential for maximal resection-induced intestinal growth. Rats received systemic or perivagal capsaicin or ganglionectomy before 70% midjejunoileal resection or transection and were fed orally or by total parenteral nutrition (TPN) for 7 days after surgery. Growth of residual bowel was assessed by changes in mucosal mass, protein, DNA, and histology. Both systemic and perivagal capsaicin significantly attenuated by 48-100% resection-induced increases in ileal mucosal mass, protein, and DNA in rats fed orally. Villus height was significantly reduced in resected rats given capsaicin compared with vehicle. Sucrase specific activity in jejunal mucosa was not significantly different; ileal mucosal sucrase specific activity was significantly increased by resection in capsaicin-treated rats. Capsaicin did not alter the 57% increase in ileal proglucagon mRNA or the 150% increase in plasma concentration of bioactive GLP-2 resulting from resection in orally fed rats. Ablation of spinal/splanchnic innervation by ganglionectomy failed to attenuate resection-induced adaptive growth. In TPN rats, capsaicin did not attenuate resection-induced mucosal growth. We conclude that vagal afferents are not essential for GLP-2 secretion when the ileum has direct contact with luminal nutrients after resection. In summary, vagal afferent neurons are essential for maximal resection-induced intestinal adaptation through a mechanism that appears to involve stimulation by luminal nutrients.     

Efficiency of adjuvant active specific immunization with Newcastle disease virus modified tumor cells in colorectal cancer patients following resection of liver metastases: results of a prospective randomized trial

Purpose  Metastatic disease is a major cause of mortality in colorectal cancer patients. Even after complete resection of isolated liver metastases, recurrence develops in the majority of patients. Therefore, development of strategies to prevent recurrent liver metastases is of major clinical importance. The present prospectively randomised phase III trial investigates the efficiency of active specific immunotherapy (ASI) after liver resection for hepatic metastases of colorectal cancer. Methods  Patients with histologically confirmed liver metastases from colorectal cancer were randomised to the vaccination or control group. After complete resection of liver metastases, patients randomised to the vaccination group received six doses of Newcastle disease virus (NDV) infected autologous tumour cell vaccine (ATV-NDV). The primary end-point was overall survival, secondary end-points were disease-free survival and metastases-free survival. Results  Fifty-one patients were enrolled in the study with 50 patients available for analysis. The follow-up period was 116.1 ± 23.8 month in the vaccination arm and 112.4 ± 18.5 month in the control group. In the total patient group, no differences in the primary and secondary end-points were detected. Most interestingly, subgroup analysis revealed a significant advantage for vaccinated colon cancer patients with respect to overall survival [hazard ratio: 3.3; 95%, confidence interval (CI): 1.0–10.4; P = 0.042] and metastases-free survival (hazard ratio: 2.7; 95%, CI: 1.0–7.4; P = 0.047) in the intention-to-treat analysis. Conclusion  Active specific immunotherapy in unselected colorectal cancer patients was not effective for prevention of recurrent metastatic disease. However, in colon cancer patients, ASI with ATV-NDV appears to be beneficial prolonging overall and metastases-free survival.     

Modulatory Effects of <Emphasis Type="Italic">Lactobacillus salivarius</Emphasis> on Intestinal Mucosal Immunity of Piglets

Recent studies have demonstrated that lactobacilli or their cell components can improve certain immune function in animals. The aim of this study is to investigate the effects of porcine lactobacilli on the intestinal mucosal immunity of piglets. Neonatal piglets were used as a model and were orally administrated with Lactobacillus salivarius B1 isolated from the duodenal mucosa of a healthy piglet. The feces of the piglets were collected on days 7, 14, and 21 for intestinal microflora analysis. On day 28, the piglets were sacrificed, and their intestinal mucosa samples were immediately collected to investigate the changes in intestinal morphological and immunocompetent cells. Finally, the expression of cytokines and TLRs was detected in the different intestinal segments. The results indicate that L. salivarius B1 can partially ameliorate the microflora of the feces and increase the number of intestinal immunocompetent cells, as the intraepithelial lymphocyte (P < 0.05), and the IgA-producing cells (P < 0.01) in the lactobacilli-treated group were all increased compared with those in the control group. Enhanced expression of the cytokine IL-6 gene was also observed in the ileum (P < 0.05). Moreover, L. salivarius B1 can also upregulate the expression of TLR2 in the intestinal tract at the gene and protein levels (P < 0.05). The results demonstrate that L. salivarius B1 is beneficial for the maturation of the intestinal mucosal immune system and elicited local immunomodulatory activities. In addition, the modulatory effects of L. salivarius B1 on mucosal immunity mainly depend on its extracellular components.     

Proteomic analysis of plasma from rats following total parenteral nutrition‐induced liver injury

Total parenteral nutrition (TPN) is provided as the primary nitrogen source to manage patients with intestinal failure who were not able to sustain themselves on enteral feeds. The most common complication of long‐term TPN use is hepatitis. A proteomic approach was used to identify proteins that are differentially expressed in the plasma of rats following TPN‐related acute liver injury. Six male rats were randomly assigned to either the saline infusion control group or the TPN infusion group. Our results demonstrate that TPN infusion in rats resulted in hepatic dysfunction and hepatocyte apoptosis. Five proteins that were differentially expressed between TPN infusion and normal rats were determined and validated in vivo. Fascinatingly, the proteomic differential displays, downregulated proteins included peroxiredoxin 2 (PRDX2), alpha‐1‐antiproteinase (A1AT), and fibrinogen gamma chain (FIBG), which were involved in oxidative stress, inflammatory respondence and cells apoptosis. After TPN infusion, two protein spots showed increased expression, namely, the glucagon receptor (GLR) protein and apolipoprotein A‐1 (APOA1), which may mediate the effects of TPN administration on glycogen and lipid metabolism. In this study, proteomic analysis suggested TPN‐related acute liver injury could be involved in limiting cellular protection mechanisms against oxidative stress‐induced apoptosis. On the basis of the results, we also give molecular evidences replying TPN‐related hepatitis.     

Supplementary choline attenuates olive oil lipid emulsion‐induced enterocyte apoptosis through suppression of CELF1/AIF pathway

Enterocyte apoptosis induced by lipid emulsions is a key cause of intestinal atrophy under total parenteral nutrition (TPN) support, and our previous work demonstrated that olive oil lipid emulsion (OOLE) could induce enterocyte apoptosis via CUGBP, Elav‐like family member 1 (CELF1)/ apoptosis‐inducing factor (AIF) pathway. As TPN‐associated complications are partially related to choline deficiency, we aimed to address whether choline supplementation could attenuate OOLE‐induced enterocyte apoptosis. Herein we present evidence that supplementary choline exhibits protective effect against OOLE‐induced enterocyte apoptosis both in vivo and in vitro. In a rat model of TPN, substantial reduction in apoptotic rate along with decreased expression of CELF1 was observed when supplementary choline was added to OOLE. In cultured Caco‐2 cells, supplementary choline attenuated OOLE‐induced apoptosis and mitochondria dysfunction by suppressing CELF1/AIF pathway. Compared to OOLE alone, the expression of CELF1 and AIF was significantly decreased by supplementary choline, whereas the expression of Bcl‐2 was evidently increased. No obvious alterations were observed in Bax expression and caspase‐3 activation. Mechanistically, supplementary choline repressed the expression of CELF1 by increasing the recruitment of CELF1 mRNA to processing bodies, thus resulting in suppression of its protein translation. Taken together, our data suggest that supplementary choline exhibits effective protection against OOLE‐induced enterocyte apoptosis, and thus, it has the potential to be used for the prevention and treatment of TPN‐induced intestinal atrophy.     

Prevalence of Diabetes,Prediabetes, and Stress Hyperglycemia: Insulin Therapy and Metabolic Control in Patients on Total Parenteral Nutrition (Prospective Multicenter Study)

ObjectiveThe prevalence of carbohydrate metabolism disorders in patients who receive total parenteral nutrition (TPN) is not well known. These disorders can affect the treatment, metabolic control, and prognosis of affected patients. The aims of this study were to determine the prevalence in noncritically ill patients on TPN of diabetes, prediabetes, and stress hyperglycemia; the factors affecting hyperglycemia during TPN; and the insulin therapy provided and the metabolic control achieved.MethodsWe undertook a prospective multicenter study involving 19 Spanish hospitals. Noncritically ill patients who were prescribed TPN were included, and data were collected on demographic, clinical, and laboratory variables (glycated hemoglobin, C-reactive protein [CRP], capillary blood glucose) as well as insulin treatment.ResultsThe study included 605 patients. Before initiation of TPN, the prevalence of known diabetes was 17.4%, unknown diabetes 4.3%, stress hyperglycemia 7.1%, and prediabetes 27.8%. During TPN therapy, 50.9% of patients had at least one capillary blood glucose of > 180 mg/dL. Predisposing factors were age, levels of CRP and glycated hemoglobin, the presence of diabetes, infectious complications, the number of grams of carbohydrates infused, and the administration of glucose-elevating drugs. Most (71.6%) patients were treated with insulin. The mean capillary blood glucose levels during TPN were: known diabetes (178.6 ± 46.5 mg/dL), unknown diabetes (173.9 ± 51.9), prediabetes (136.0 ± 25.4), stress hyperglycemia (146.0 ± 29.3), and normal (123.2 ± 19.9) (P < .001).ConclusionThe prevalence of carbohydrate metabolism disorders is very high in noncritically ill patients on TPN. These disorders affect insulin treatment and the degree of metabolic control achieved. (Endocr Pract. 2015;21:59-67)     

The role of glutamine in the immune system and in intestinal function in catabolic states

Summary Glutamine is designated a non-essential amino acid: however, evidence is accumulating that glutamine becomes essential when catabolic conditions prevail.It has been established that glutamine is an important fuel for lymphocytes and macrophages, even when resting. Plasma and muscle glutamine concentrations are decreased after trauma such as burns, major surgery, and in sepsis. The effectiveness of the immune system is decreased after trauma: this may be due, in part, to the decrease in plasma glutamine concentrations.Most studies on sepsis in humans have shown plasma glutamine concentrations to bedecreased: this may be due to an increased rate of utilization of glutamine by lymphocytes and macrophages during proliferation or phagocytosis. In contrast, several studies on rats showincreased plasma glutamine levels in sepsis. A species difference in the way in which glutamine is metabolised could be the main reason for the conflicting results. Other contributory factors could be diurnal variation and timing of sample collection.A substantial amount of dietary glutamine is taken up by intestinal cells. When the supply of glutamine via the diet is decreased, glutamine is taken up from the circulation by the intestine. In total parenteral nutrition (TPN) sepsis can sometimes occur because the gut is rested, leading to villous atrophy and increased gut mucosal barrier permeability. There is now a move towards the use of enteral nutrition in preference to TPN. Provision of exogenous glutamine has had beneficial effects in humans and animals, particularly in improving intestinal function. The safety and efficacy of glutamine administration to humans is discussed in detail.     

Hypotransferrinemia and changes in plasma lipid and metabolic patterns in sepsis

This study was performed to obtain a characterization of the changes in plasma transferrin (Tf, g/L) in sepsis. More than four hundred determinations of Tf, and of a large series of simultaneously collected blood and hemodynamic variables, were obtained in 17 patients with post-traumatic sepsis. Tf during sepsis was consistently low (mean ± SD = 1.46 ± 0.46) however fluctuated markedly according to changes in metabolic and hemodynamic patterns. Regression analysis showed that decreases in Tf were simultaneously correlated with the plasma lipid pattern (in particular with decreasing cholesterol and increasing triglycerides), with decreases in albumin and peripheral O₂ extraction, and with increasing cardiac index (p < 0.001 for all). Decreases in Tf were moderated by increasing the parenteral amino acid dose (p < 0.001). Combinations of these variables in multiple regressions explained nearly 80% of the variability of Tf. There were no similar correlations for other acute phase proteins except ceruloplasmin, which showed opposite changes compared to those of Tf. These results show that within the hypotransferrinemia which characterizes sepsis, Tf may oscillate remaining strongly correlated with changes in metabolic and hemodynamic patterns, which may account for nearly 80% of the variability of Tf.     

Enteral bile acid treatment improves parenteral nutrition-related liver disease and intestinal mucosal atrophy in neonatal pigs

Total parenteral nutrition (TPN) is essential for patients with impaired gut function but leads to parenteral nutrition-associated liver disease (PNALD). TPN disrupts the normal enterohepatic circulation of bile acids, and we hypothesized that it would decrease intestinal expression of the newly described metabolic hormone fibroblast growth factor-19 (FGF19) and also glucagon-like peptides-1 and -2 (GLP-1 and GLP-2). We tested the effects of restoring bile acids by treating a neonatal piglet PNALD model with chenodeoxycholic acid (CDCA). Neonatal pigs received enteral feeding (EN), TPN, or TPN + CDCA for 14 days, and responses were assessed by serum markers, histology, and levels of key regulatory peptides. Cholestasis and steatosis were demonstrated in the TPN group relative to EN controls by elevated levels of serum total and direct bilirubin and also bile acids and liver triglyceride (TG) content. CDCA treatment improved direct bilirubin levels by almost fourfold compared with the TPN group and also normalized serum bile acids and liver TG. FGF19, GLP-1, and GLP-2 were decreased in plasma of the TPN group compared with the EN group but were all induced by CDCA treatment. Intestinal mucosal growth marked by weight and villus/crypt ratio was significantly reduced in the TPN group compared with the EN group, and CDCA treatment increased both parameters. These results suggest that decreased circulating FGF19 during TPN may contribute to PNALD. Moreover, we show that enteral CDCA not only resolves PNALD but acts as a potent intestinal trophic agent and secretagogue for GLP-2.     

GLP-2 stimulates intestinal growth in premature TPN-fed pigs by suppressing proteolysis and apoptosis

We wished to determine whether exogenous glucagon-like peptide (GLP)-2 infusion stimulates intestinal growth in parenterally fed immature pigs. Piglets (106-108 days gestation) were given parenteral nutrient infusion (TPN), TPN + human GLP-2 (25 nmol. kg(-1). day(-1)), or sow's milk enterally (ENT) for 6 days. Intestinal protein synthesis was then measured in vivo after a bolus dose of [1-(13)C]phenylalanine, and degradation was calculated from the difference between protein accretion and synthesis. Crypt cell proliferation and apoptosis were measured in situ by 5-bromodeoxyuridine (BrdU) and terminal dUTP nick-end labeling (TUNEL), respectively. Intestinal protein and DNA accretion rates and villus heights were similar in GLP-2 and ENT pigs, and both were higher (P < 0.05) than in TPN pigs. GLP-2 decreased fractional protein degradation rate, whereas ENT increased fractional protein synthesis rate compared with TPN pigs. Percentage of TUNEL-positive cells in GLP-2 and ENT groups was 48 and 64% lower, respectively, than in TPN group (P < 0.05). However, ENT, but not GLP-2, increased percentage of BrdU-positive crypt cells above that in TPN piglets. We conclude that GLP-2 increases intestinal growth in premature, TPN-fed pigs by decreasing proteolysis and apoptosis, whereas enteral nutrition acts via increased protein synthesis and cell proliferation and decreased apoptosis.     

High central venous oxygen saturation is associated with mitochondrial dysfunction in septic shock: A prospective observational study

To test the hypothesis that an impaired mitochondrial function is associated with altered central venous oxygen saturation (ScvO₂), venous-to-arterial carbon dioxide tension difference (delta PCO₂) or serum lactate in sepsis patients. This prospective cohort study was conducted in a single tertiary emergency department between April 2017 and March 2019. Patients with suspected sepsis were included in the study. Serum lactate was obtained in sepsis, ScvO₂ and delta PCO₂ were evaluated in septic shock patients. Mitochondrial function was determined from the peripheral blood mononuclear cells. Forty-six patients with suspected sepsis were included. Of these, twenty patients were septic shock. Mitochondrial oxidative stress levels were increased in the high ScvO₂ group (ScvO₂ > 80%, n = 6), compared with the normal (70%-80%, n = 9) and low ScvO₂ (<70%, n = 5) groups. A strong linear relationship was observed between the mitochondrial oxidative stress and ScvO₂ (r = .75; P = .01). However, mitochondrial respiration was increased in the low ScvO₂ group. In addition, mitochondrial complex II protein levels were significantly decreased in the high ScvO₂ group (P < .05). Additionally, there was no correlation between serum lactate, delta PCO₂, and mitochondria oxidative stress or mitochondria function. ScvO₂ can be potentially useful for developing new therapeutics to reduce mitochondrial dysfunction in septic shock patient.