Basal nutrition promotes human intestinal epithelial (Caco-2) proliferation, brush border enzyme activity, and motility

Management of Short Bowel Syndrome (SBS) and Intestinal Failure

Short bowel syndrome (SBS) is a chronic disease whose natural history requires a changing array of management strategies over time. Chief amongst these is the chronic use of parenteral nutrition (PN) to ensure adequate nutritional intake. With time and appropriate management, approximately half of all SBS patients will successfully regain a functional, baseline level of intrinsic bowel function that will allow for them to achieve PN independence. However, the other half of SBS patients will progress into chronic intestinal failure which warrants a change in therapy to include more aggressive medical and potentially surgical measures. This review examines the evolving treatment strategies involved in the management of SBS as well as intestinal failure.

RNA Sequencing of Intestinal Enterocytes Pre- and Post-Roux-en-Y Gastric Bypass Reveals Alteration in Gene Expression Related to Enterocyte Differentiation, Restitution, and Obesity with Regulation by Schlafen 12

BACKGROUND

The intestinal lining renews itself in a programmed fashion that can be affected by adaptation to surgical procedures such as gastric bypass.

METHODS

To assess adaptive mechanisms in the human intestine after Roux-en-Y gastric bypass (RYGB), we biopsied proximal jejunum at the anastomotic site during surgery to establish a baseline and endoscopically re-biopsied the same area 6-9 months after bypass for comparison. Laser microdissection was performed on pre- and post-RYGB biopsies to isolate enterocytes for RNA sequencing.

RESULTS

RNA sequencing suggested significant decreases in gene expression associated with G2/M DNA damage checkpoint regulation of the cell cycle pathway, and significant increases in gene expression associated with the CDP-diacylglycerol biosynthesis pathway TCA cycle II pathway, and pyrimidine ribonucleotide salvage pathway after RYGB. Since Schlafen 12 (SLFN12) is reported to influence enterocytic differentiation, we stained mucosa for SLFN12 and observed increased SLFN12 immunoreactivity. We investigated SLFN12 overexpression in HIEC-6 and FHs 74 Int intestinal epithelial cells and observed similar increased expression of the following genes that were also increased after RYGB: HES2, CARD9, SLC19A2, FBXW7, STXBP4, SPARCL1, and UTS.

CONCLUSIONS

Our data suggest that RYGB promotes SLFN12 protein expression, cellular mechanism and replication pathways, and genes associated with differentiation and restitution (HES2, CARD9, SLC19A2), as well as obesity-related genes (FBXW7, STXBP4, SPARCL1, UTS).

Schlafen 12 mediates the effects of butyrate and repetitive mechanical deformation on intestinal epithelial differentiation in human Caco-2 intestinal epithelial cells

Intestinal epithelial differentiation may be stimulated by diverse pathways including luminal short-chain fatty acids and repetitive mechanical deformation engendered by villous motility and peristalsis. Schlafen 12 (SLFN12) is a cytosolic protein that stimulates sucrase-isomaltase (SI) expression. We hypothesized that two disparate differentiating stimuli, butyrate and repetitive deformation, would each stimulate SLFN12 expression in human Caco-2 intestinal epithelial cells and that increased SLFN12 expression would contribute to the differentiating activity of the human Caco-2 intestinal epithelial cells. We stimulated Caco-2 cells with 1-2 mM butyrate or repetitive mechanical deformation at 10 cycles/min at an average 10% strain, and measured SLFN12 and SI expression by qRT-PCR. Sodium butyrate enhanced SLFN12 expression at both 1 mM and 2 mM although SI expression was only significantly increased at 2 mM. Repetitive deformation induced by cyclic mechanical strain also significantly increased both SLFN12 and SI gene expression. Reducing SLFN12 by siRNA decreased basal, deformation-stimulated, and butyrate-stimulated SLFN12 levels, compared to control cells treated with non-targeting siRNA, although both deformation and butyrate were still able to stimulate SLFN12 expression in siRNA-treated cells compared to control cells treated with the same siRNA. This attenuation of the increase in SLFN12 expression in response to mechanical strain or butyrate was accompanied by parallel attenuation of SI expression. Butyrate stimulated SI-promoter activity, and reducing SLFN12 by siRNA attenuated butyrate-induced SI-promoter activity. These data suggest that SLFN12 mediates at least in part the stimulation by both butyrate and repetitive mechanical deformation of sucrase-isomaltase, a late stage differentiation marker in human intestinal epithelial cells.

Exclusive enteral nutrition protects against inflammatory bowel disease by inhibiting NF‑κB activation through regulation of the p38/MSK1 pathway

Although enteral nutrition therapy for inflammatory bowel disease has been confirmed to be an effective treatment method, the exact mechanism responsible for the effects of enteral nutrition remains unclear. The aim of the present study was to investigate the protective effect of exclusive enteral nutrition (EEN) against colitis, and to elucidate the potential mechanisms by inhibiting p65 activation via regulating the p38/mitogen‑ and stress‑activated protein kinase‑1 (MSK1) pathway. Experiments were performed by establishing dextran sulfate sodium (DSS)‑mice colitis and picrylsulfonic acid solution (TNBS)‑induced rat colitis, and the results demonstrated that EEN treatment attenuated body weight loss, colon length shortening and colonic pathological damage caused by colitis. EEN also inhibited inflammatory cells infiltration and decreased myeloperoxidase and inducible nitric oxide synthase activities. Furthermore, EEN significantly reduced the production of pro‑inflammatory mediators in serum and the colon. Mechanically, EEN suppressed activation of p65 by inhibiting the p38/MSK1 pathway. In conclusion, the present study demonstrated that EEN attenuated DSS‑ and TNBS‑induced colitis by inhibiting p65 activation via regulating the p38/MSK1 pathway, thus suggesting that EEN is effective in the treatment of colitis.

Implantable synthetic organoid matrices for intestinal regeneration

Organoids are a powerful tool to study both physiological and disease processes. A completely synthetic matrix assembled from exchangeable modular parts has been developed and not only supports proliferation of human intestinal organoids derived from pluripotent embryonic stem cells, but also augments subsequent ad vivo implantation into injured murine colon.

Bacterial nutrient foraging in a mouse model of enteral nutrient deprivation: insight into the gut origin of sepsis

Total parenteral nutrition (TPN) leads to a shift in small intestinal microbiota with a characteristic dominance of Proteobacteria This study examined how metabolomic changes within the small bowel support an altered microbial community in enterally deprived mice. C57BL/6 mice were given TPN or enteral chow. Metabolomic analysis of jejunal contents was performed by liquid chromatography/mass spectrometry (LC/MS). In some experiments, leucine in TPN was partly substituted with [¹³C]leucine. Additionally, jejunal contents from TPN-dependent and enterally fed mice were gavaged into germ-free mice to reveal whether the TPN phenotype was transferrable. Small bowel contents of TPN mice maintained an amino acid composition similar to that of the TPN solution. Mass spectrometry analysis of small bowel contents of TPN-dependent mice showed increased concentration of ¹³C compared with fed mice receiving saline enriched with [¹³C]leucine. [¹³C]leucine added to the serosal side of Ussing chambers showed rapid permeation across TPN-dependent jejunum, suggesting increased transmucosal passage. Single-cell analysis by fluorescence in situ hybridization (FISH)-NanoSIMS demonstrated uptake of [¹³C]leucine by TPN-associated bacteria, with preferential uptake by Enterobacteriaceae Gavage of small bowel effluent from TPN mice into germ-free, fed mice resulted in a trend toward the proinflammatory TPN phenotype with loss of epithelial barrier function. TPN dependence leads to increased permeation of TPN-derived nutrients into the small intestinal lumen, where they are predominately utilized by Enterobacteriaceae The altered metabolomic composition of the intestinal lumen during TPN promotes dysbiosis.

Reversal of intestinal failure-associated liver disease (IFALD): emphasis on its multifactorial nature

Patients with intestinal failure (IF) and home parenteral nutrition commonly develop abnormal liver function tests. The presentations of IF-associated liver disease (IFALD) range from mild cholestasis or steatosis to cirrhosis and decompensated liver disease. We describe the reversal of IFALD in an adult patient with IF secondary to severe Crohn's disease and multiple small bowel resections. The patient developed liver dysfunction and pathology consistent with IFALD. Multiple causal factors were implicated, including nutrition-related factors, catheter sepsis and the use of hepatotoxic medications. Multidisciplinary treatment in a tertiary IF referral centre included aggressive sepsis management, discontinuation of hepatotoxic medications and a reduction of parenteral nutrition dependency through optimisation of enteral nutrition via distal enteral tube feeding. Upon this, liver function tests normalised.

Kinetics of phytosterol metabolism in neonates receiving parenteral nutrition

BACKGROUND

Phytosterols in soybean oil (SO) lipids likely contribute to parenteral nutrition-associated liver disease (PNALD) in infants. No characterization of phytosterol metabolism has been done in infants receiving SO lipids.

METHODS

In a prospective cohort study, 45 neonates (36 SO lipid vs. 9 control) underwent serial blood sample measurements of sitosterol, campesterol, and stigmasterol. Mathematical modeling was used to determine pharmacokinetic parameters of phytosterol metabolism and phytosterol exposure.

RESULTS

Compared to controls, SO lipid-exposed infants had significantly higher levels of sitosterol and campesterol (P < 0.01). During SO lipid infusion, sitosterol and campesterol reached half of steady-state plasma levels within 1.5 and 0.8 d, respectively. Steady-state level was highest for sitosterol (1.68 mg/dl), followed by campesterol (0.98 mg/dl), and lowest for stigmasterol (0.01 mg/dl). Infants born < 28 wk gestational age had higher sitosterol steady-state levels (P = 0.03) and higher area under the curve for sitosterol (P = 0.03) during the first 5 d of SO lipid (AUC5) than infants born ≥ 28 wk gestational age.

CONCLUSION

Phytosterols in SO lipid accumulate rapidly in neonates. Very preterm infants receiving SO lipid have higher sitosterol exposure, and may have poorly developed mechanisms of eliminating phytosterols that may contribute to their vulnerability to PNALD.

Management of short bowel syndrome

Most intestinal failure in children is due to short bowel syndrome (SBS) where congenital or acquired lesions have led to an extensive loss of intestinal mass. The vast majority of morbidity and mortality of patients with SBS is due to complications secondary to their long term dependence on parenteral nutrition. In response to SBS, the intestine undergoes a process of remodeling termed adaptation. Principles guiding the medical management of SBS include providing adequate parenteral nutrition, fluids and electrolytes for growth and normal development, promoting small bowel adaptation, and preventing and treating complications related to the patient's underlying disease and their parenteral nutrition. Catheter associated blood stream infection (CABSI) is major source of morbidity and mortality in patients with intestinal failure from SBS. Intestinal failure associated liver disease (IFALD)is another major source of morbidity and mortality in patients with SBS. IFALD is the most consistent negative predictor of outcome including death and continued parenteral nutrition dependence. Enteral nutrition is critical for intestinal adaptation and preventing IFALD. Patients with SBS who develop dilated dysmotile segments may benefit from autologous intestinal reconstruction surgery (AIRS) with the goal of decreasing stasis and disordered motility through intestinal narrowing and lengthening. Patients with SBS should be referred for transplantation if they have failed intestinal rehabilitation including AIRS, have no reasonable chance for enteral feeding tolerance, develop irreversible IFALD, have recurrent sepsis, or have exhausted their central venous access sites. With improvements in medical and surgical care, overall survival of patients with SBS now exceeds 90%.

Effect of enteral nutrition on dextran sulfate sodium-induced colitis in rats

OBJECTIVE

To study the effect of enteral nutrition (EN) on dextran sulfate sodium (DSS)-induced colitis in rats.

METHODS

Eighty-four Sprague-Dawley rats were divided into 7 groups (12 rats in each group). The blank control group was given ordinary laboratory feed and drinking water. The experimental groups received 5% DSS as drinking water for 7 days. Of the experimental groups, the model control group received ordinary laboratory feed, protein based enteral nutrition (PEN) was fed in the PEN group, while other groups received ordinary laboratory feed plus 5-aminosalicylic acid (5-ASA), methyl-prednisolone, Lactobacillus or glutamine, respectively. On the 8th day, all the rats were sacrificed. Inflammatory scores were assessed from colonic mucosa. Blood culture from inferior vena cava, fecal culture and secretary immunoglobulin-A (S-IgA) levels from colonic contents were determined.

RESULTS

Colon inflammatory scores of Lactobacillus, PEN, glutamine and drug-treated groups were lower than that of the model control group (P < 0.01). The ratios of bacteria translocation in the EN (PEN, Lactobacillus and glutamine) groups were lower than that in the model control group (P < 0.0083). Fecal Lactobacilli in the Lactobacillus and glutamine groups were higher than that in the model control group (P < 0.05). S-IgA levels in colonic contents of the PEN and 5-ASA group were lower than that in the model control group (P < 0.05).

CONCLUSIONS

EN is an effective therapy for treating DDS-induced colitis. EN could alleviate damage, promote the repair of colonic epithelial cells and inhibit bacterial translocation. Lactobacillus and glutamine could also increase the Lactobacilli in colon.

Innovative parenteral and enteral nutrition therapy for intestinal failure

Children with intestinal failure (IF) suffer from insufficient intestinal length or function, making them dependent on parenteral nutrition (PN) for growth and survival. PN and its components are associated with many complications ranging from simple electrolyte abnormalities to life-threatening PN-associated liver disease, which is also called intestinal failure-associated liver disease (IFALD). From a nutrition perspective, the ultimate goal is to provide adequate caloric requirements and make the transition from PN to full enteral nutrition (EN) successful. Upon review of the literature, we have summarized the most effective and innovative PN and EN therapies for this patient population. Antibiotic-coated catheters and antibiotic or ethanol locks can be implemented, as they appear effective in reducing catheter-related infection and thus further reduce the risk of IFALD. Lipid emulsions should be given judiciously. The use of an omega-3 fatty acid-based formulation should be considered in patients who develop IFALD. Trophic feeding is important for intestinal adaptation, and EN should be initiated early to help wean patients from PN. Long-term management of children with IF continues to be an emerging field. We have entered uncharted territory as more children survive complications of IF and IFALD. Careful monitoring and individualized management to ensure maintenance of growth while avoiding complications are the keys to successful patient outcomes.

Paradigms for mechanical signal transduction in the intestinal epithelium. Category: molecular, cell, and developmental biology

Diverse physical forces including deformation or strain, pressure, and shear stress affect the intestinal mucosa during normal function, and mucosal biology is altered in pathological states in which these forces alter. Taken together with evidence in other tissues and cell types that physical forces can affect cell biology, this has led to the hypothesis that repetitively applied physical forces can initiate intracellular signals that alter intestinal epithelial proliferation and phenotype. This review outlines the nature of such forces and summarizes in vivo and in vitro evidence in support of the paradigm that repetitive force is trophic for the intestinal mucosa via a complex cascade of intracellular signals.

Enteral and parenteral nutrition in the care of patients with short-bowel syndrome

Short-bowel syndrome is a challenging entity for the gastroenterologist, requiring integration of medical, nutritional, surgical and psychological therapies. Treatment must be based on the patient's age, remaining gastrointestinal anatomy, baseline nutritional status and underlying general health as well as the numerous complications which may arise. This chapter reviews physiological alterations that occur with short-bowel syndrome and how therapies can be tailored to most adequately meet the needs of these patients. Emphasis on early stages of therapy to enhance intestinal adaptation is focused on as management during this time has a significant impact on the long-term outcome of these patients.

Changes in epithelial cell turnover and extracellular matrix in human small intestine after TPN

BACKGROUND

The atrophy and architectural remodeling of the jejunal mucosa arising in adults receiving total parenteral nutrition (TPN) has been suggested to originate from a disturbance in tissue homeostasis. The present study aims at examining (1) whether there are differences in proliferation and apoptosis of epithelial cells between enterally and parenterally nourished patients and (2) whether the distribution pattern of extracellular matrix (ECM) proteins known to influence cell turnover along the the crypt-villus axis is changed after TPN.

METHODS

The mitotic frequency and the proliferation index [using an antibody against Ki-67 antigen (MIB 1)] were determined on epoxy semithin and paraffin sections, respectively. Morphological techniques and the TUNEL assay were applied to detect apoptotic events. Immunolocalization of collagen IV, laminin, fibronectin, tenascin, and collagen VI was performed on cryosections.

RESULTS

After TPN the cell renewal was significantly enhanced, while epithelial cell death was drastically reduced. The comparison of TPN and EN patients revealed differences in the distribution patterns of the ECM proteins laminin, fibronectin, and tenascin along the crypt-villus axis. Moreover, after TPN an increased expression of collagen types IV and VI was observed.

CONCLUSIONS

TPN in human adults is associated with alterations in epithelial cell turnover and changes in expression and/or localization of ECM proteins. Thus, the inverted route of nutrient supply in patients might modify environmental tissue conditions, which may influence the interactions between intestinal epithelial cells and the extracellular matrix.

Effect of elective abdominal surgery on human colon protein synthesis in situ

OBJECTIVE

To determine the effect of elective abdominal surgery on the rate of human colon fractional protein synthesis in situ.

SUMMARY BACKGROUND DATA

Efficient intestinal protein synthesis plays an important role in the physiology and pathophysiology of the intestinal tract, allowing preservation of gut integrity and thereby preventing bacterial or endotoxin translocation. Because of species differences, animal studies have only limited applicability to human intestinal protein metabolism, and because of methodologic restrictions, no studies on colon protein synthesis in situ are available in humans.

METHODS

The authors used advanced mass spectrometry techniques (capillary gas chromatography and combustion isotope ratio mass spectrometry) to determine directly the incorporation rate of 1-[13C]-leucine into colon mucosal protein in control subjects and nonseptic postoperative patients. All subjects had a colostomy, which allowed easy access to the colon mucosa, and consecutive sampling from the same tissue was performed during continuous isotope infusion (0.16 micromol/kg per minute).

RESULTS

Control subjects demonstrated a colon protein fractional synthetic rate of 0.74 +/- 0.09% per hour. In postsurgical patients, colon protein synthesis was significantly higher and the tissue free leucine enrichment was significantly lower, compatible with an increased colon proteolytic rate.

CONCLUSIONS

Elective abdominal surgery followed by an uncomplicated postoperative course is associated with a stimulation of colon protein synthesis and possibly also of protein degradation. The postoperative rate of colon protein synthesis is, compared with other tissues, among the highest measured thus far in humans.

Imaging of three-dimensional epithelial architecture and function in cultured CaCo2a monolayers with two-photon excitation microscopy

The principal functions of the gastrointestinal tract mucosa include nutrient absorption, protein and fluid secretion, and the regulated symbiosis with intraluminal contents. Research in epithelial biology has benefited significantly from the use of cultured monolayer preparations, which closely replicate the structure and function of normal gastrointestinal mucosa. Given the explicit importance of epithelial architecture to its physiology, investigations of epithelial biology should be enhanced by the capacity to track microscopic structures and substances in live cells. In order to achieve this goal, it is necessary to employ a microscopic technique with the capability of imaging deep into the tissue or cell preparation, without adversely affecting its physiology. Two-photon excitation microscopy may constitute such a technique, due to its ability to provide fluorescence excitation of fluorophores using near infrared radiation, that has lower tissue absorption and scattering coefficients. This allows the efficient collection of light energy from sites hundreds of microns deep, with only minimal tissue damage. In this report, we have presented an introduction to the theory and practice of two-photon microscopy for imaging the GI tract epithelium, and have presented examples of its utility in discerning three-dimensional structure and function in CaCo2A epithelial cell monolayers.

Activation of Raf-1 during experimental gastric ulcer healing is Ras-mediated and protein kinase C-independent

Our previous study demonstrated increases in epidermal growth factor receptor (EGF-R) phosphorylation and receptor tyrosine kinase and extracellular signal-regulated kinase (ERK1 and ERK2) activities in the ulcer margin of experimental gastric ulcer during healing. However, the intermediate steps linking activated receptor tyrosine kinase to ERKs during ulcer healing are as yet unknown. Raf-1 is upstream of mitogen-activated protein kinases (MAPK/ERK) and can be activated by Ras-dependent and/or Ras-independent mechanisms. Therefore, we studied Raf-1 activity, its potential activators protein kinase C (PKC) and Ras, and expression and associations of adapter proteins Shc, Grb2, and Sos during experimental gastric ulcer healing. To investigate if Raf-1-ERK activation is attributable to the epithelial component of ulcer margins, we studied the effect of EGF on PKC, Ras, and ERK activities in a rat gastric epithelial cell line (RGM1). Our results demonstrate that gastric ulceration significantly increases Raf-1 kinase activity, Grb2 and Ras protein, and Shc-Grb2 and Grb2-Sos complex levels. In contrast, PKC activity and protein level were significantly decreased in the ulcer margins. In RGM1 cells, EGF significantly increased Ras and ERK2 activities without affecting PKC activity. These findings indicate that Raf-1 activation during gastric ulcer healing is Ras mediated, involves Shc-Grb2-Sos, and is PKC-independent.

Nutritional assessment in head injured patients through the study of rapid turnover visceral proteins

BACKGROUND & AIMS

Nutritional monitoring of rapid turnover visceral protein is important in the recognition of malnutrition in patients admitted to the Intensive Care Unit (ICU). We studied prealbumin and retinol-binding protein in patients who received three different kinds of artificial nutrition in order to evaluate the appropriateness of artificial nutrition.

METHODS

45 consecutive head injury patients received enteral (Group A), parenteral (Group B) or both enteral and parenteral nutrition (Group C) at random. We considered these parameters: prealbumin, retinol binding protein and nitrogen balance before (T1), after 3 (T2), 7 (T3) and 11 (T4) days after the beginning of study. Statistical analysis was performed with Kruskal-Wallis test and Bonferroni's t -test.

RESULTS

Plasma prealbumin and Retinol binding protein (RBP) showed an increasing of basal values during the study period in all groups (<< 0.0001) and more significantly in group A (Enteral nutrition P < 0. 001 vs Total parenteral nutrition (TPN) and Enteral P<< 0.01 vs Enteral and parenteral nutrition).

CONCLUSION

Data obtained in the present study indicate that a laboratory is essential for monitoring nutritional assessment and for checking the appropriateness of nutritional therapy. We found prealbumin to be the most sensitive measure and found it to be the test of choice for early assessment and intervention.

Differential regulation of intestinal and liver fatty acid-binding proteins in human intestinal cell line (Caco-2): role of collagen

Fatty acid-binding proteins (FABP) are small cytosolic proteins which are thought to play a key role in fatty acid metabolism. The intestine contains the intestinal (I-FABP) and the liver (L-FABP) isoforms, but their regulation is still poorly documented. In order to find suitable conditions for studying the regulation of the two FABP isoforms in Caco-2 cells, we investigated the effects of the presence of collagen during cell proliferation or differentiation. When collagen was present only during cell proliferation on culture dishes, I-FABP expression was enhanced, whereas sucrase-isomaltase was unaffected and L-FABP expression was merely accelerated. In contrast, when collagen was present during cell differentiation on filter inserts, both I-FABP and sucrase-isomaltase were strongly reduced, but L-FABP was not affected. Under the former conditions (the more suitable for studying FABP regulation), the peroxysome proliferator-activated receptor (PPAR) activators, clofibrate and alpha-bromopalmitate, enhanced the two isoforms. This study, which is the first one providing a quantitative protein analysis of I-FABP and L-FABP in Caco-2 cells, demonstrates different time courses of expression of these proteins during cell differentiation. It also shows that I-FABP is specifically regulated by collagen and that, under conditions optimal for their expression, both isoforms are modulated by metabolic factors.

Human Caco-2 intestinal epithelial motility is associated with tyrosine kinase and cytoskeletal focal adhesion kinase signals

Intestinal epithelial cells assume a specialized phenotype adapted to motility and mucosal healing during mucosal restitution. Since cell-matrix interactions initiate tyrosine kinase (TK) signals, we hypothesized that the regulation of the intestinal epithelial migratory phenotype may also involve TK signals, particularly via focal adhesion kinase (FAK). Caco-2 cells were seeded simultaneously at 26,000 and 6000 cells/cm2. After 4 days, the first cells were confluent, while cells in the second population were not contact-inhibited and expressed migrating lamellipodia. Cells were fractionated into Triton X-100-soluble (membrane/cytoskeletal) and -insoluble (cytosolic) fractions. TK activity in each fraction was assayed by ELISA using a synthetic substrate. FAK protein was assessed by immunoprecipitation with monoclonal anti-FAK and Western blotting. Because active FAK autophosphorylates, we also measured FAK tyrosine phosphorylation, immunoprecipitating with anti-FAK and then Western blotting for phosphotyrosine. TK activity was increased in both cytosolic and membrane/cytoskeletal fractions of migrating cells by 17.6 +/- 3.6 and 28.9 +/- 4.1%, respectively, compared to static cells (n = 11, P < 0.01). FAK protein increased in the cytosolic fraction by 90.4 +/- 20.0% (n = 5, P = 0.01), but did not change in the membrane/cytoskeletal fraction. Tyrosine phosphorylated FAK increased by 62.8 +/- 21.4% in the cytosolic fraction of migrating cells but also by 46.6 +/- 38.4% in the membrane/cytoskeletal fraction (n = 5, P < 0.05). These data suggest that intestinal epithelial cell migration is associated with increases in both cytosolic and cytoskeletal TK activity and upregulation of cytosolic FAK protein. The increase in cytoskeletal FAK phosphorylation without increased FAK protein suggests autophosphorylation and increased cytoskeletal FAK activity. The migrating intestinal epithelial phenotype may therefore be modulated by TK signals including cytoskeletal FAK activity.

Postoperative nutrition in surgery for major trauma

Research in the area of the nutritional support of trauma patients has continued to focus on a few main areas: the effect that the route, timing and type of feeding has on patient outcome, nutritional assessment and mucosal immunity. This year a nutritional conference has released a paper, summarizing the current state of research in this area, that generated some controversy.