[APPENDECTOMY FOR COMPLICATED APPENDICITIS IN CHILDREN--LAPAROSCOPIC OR OPEN?].

INTRODUCTION: Laparoscopic appendectomy (LA) is widely accepted for simple appendicitis but it is still debatable in complicated cases (gangrenous or perforated appendicitis). AIM: The purpose of the present study was to evaluate the outcomes of LA versus open appendectomy (OA) in uncomplicated and complicated appendicitis in children. METHODS: A retrospective analysis of the clinical data of children (< 18 years old) who underwent LA and CA from 2008 to 2011 was performed. The incidental appendectomies were excluded. The patients were divided into four groups according to the severity of the disease (uncomplicated vs complicated) and by the surgical approach (LA vs OA). Data were compared with regard to demographic features, pre-operative, intra-operative and post-operative findings. MAIN RESULTS: A total of 335 children underwent urgent appendectomy during this period. The overall rate of perforated appendicitis was 26.9%; 143 patients (42.7%) underwent LA and 192 patients (57.3%) underwent CA. Operative times and complication rates did not differ significantly between LA and OA in either complicated to uncomplicated appendicitis; LOS was shorter in the uncomplicated group (2.14 ± 0.17 vs 3.15 ± 0.14, p < 0.01). Two patients from the uncomplicated group underwent conversions form LA to OA (conversion rate of 1.36%) because of intraoperative bleeding, and one patient in the OA-complicated group had a cecal injury. There were no mortalities in this group. CONCLUSIONS: Laparoscopic appendectomy for complicated appendicitis in children is feasible and safe, does not harbor any risks in comparison to the open traditional procedure, and allows the benefits of better view, flexible angle of approach and cosmesis.

The role of Wnt/ß-catenin signaling in enterocyte turnover during methotrexate-induced intestinal mucositis in a rat.

BACKGROUND/AIMS: Intestinal mucositis is a common side-effect in patients who receive aggressive chemotherapy. The Wnt signaling pathway is critical for establishing and maintaining the proliferative compartment of the intestine. In the present study, we tested whether Wnt/ß-catenin signaling is involved in methotrexate (MTX)-induced intestinal damage in a rat model. METHODS: Non-pretreated and pretreated with MTX Caco-2 cells were evaluated for cell proliferation and apoptosis using FACS analysis. Adult rats were divided into three experimental groups: Control rats; MTX-2 animals were treated with a single dose of MTX given IP and were sacrificed on day 2, and MTX-4 rats were treated with MTX similar to group B and were sacrificed on day 4. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation, and enterocyte apoptosis were measured at sacrifice. Real Time PCR and Western blot was used to determine the level of Wnt/ß-catenin related genes and protein expression. RESULTS: In the vitro experiment, treatment with MTX resulted in marked decrease in early cell proliferation rates following by a 17-fold increase in late cell proliferation rates compared to early proliferation. Treatment with MTX resulted in a significant increase in early and late apoptosis compared to Caco-2 untreated cells. In the vivo experiment, MTX-2 and MTX-4 rats demonstrated intestinal mucosal hypoplasia. MTX-2 rats demonstrated a significant decrease in FRZ-2, Wnt 3A Wnt 5A, ß-catenin, c-myc mRNA expression and a significant decrease in ß-catenin and Akt protein levels compared to control animals. Four days following MTX administration, rats demonstrated a trend toward a restoration of Wnt/ß-catenin signaling especially in ileum. CONCLUSIONS: Wnt/ß-catenin signaling is involved in enterocyte turnover during MTX-induced intestinal mucositis in a rat.

Glutamine attenuates the inhibitory effect of methotrexate on TLR signaling during intestinal chemotherapy-induced mucositis in a rat.

Toll-like receptor 4 (TLR-4) 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 glutamine (GLN) on TLR-4 signaling in intestinal mucosa during methotrexate (MTX)-induced mucositis in a rat. Male Sprague-Dawley rats were randomly assigned to one of four experimental groups of 8 rats each: 1) control rats; 2) CONTR-GLN animals were treated with oral glutamine given in drinking water (2%) 48 hours before and 72 hours following vehicle injection; 3) MTX-rats were treated with a single IP injection of MTX (20 mg/kg); and 4) MTX-GLN rats were pre-treated with oral glutamine similar to group B, 48 hours before and 72 hours after MTX injection. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined 72 hours following MTX injection. The expression of TLR-4, MyD88 and TRAF6 in the intestinal mucosa was determined using real time PCR, Western blot and immunohistochemistry. MTX-GLN rats demonstrated a greater jejunal and ileal mucosal weight and mucosal DNA, greater villus height in ileum and crypt depth and index of proliferation in jejunum and ileum, compared to MTX animals. The expression of TLR-4 and MyD88 mRNA and protein in the mucosa was significantly lower in MTX rats versus controls animals. The administration of GLN increased significantly the expression of TLR-4 and MyD88 (vs the MTX group). In conclusion, treatment with glutamine was associated with up-regulation of TLR-4 and MyD88 expression and a concomitant decrease in intestinal mucosal injury caused by MTX-induced mucositis in a rat.

Wnt/ß-catenin signaling cascade down-regulation following massive small bowel resection in a rat.

BACKGROUND: Growing evidence suggests that the Wnt/ß-catenin signaling cascade is implicated in the control of stem cell activity, cell proliferation, lineage commitment, and cell survival during normal development and tissue regeneration of the gastrointestinal epithelium. The roles of this signaling cascade in stimulation of cell proliferation after massive small bowel resection are unknown. The purpose of this study was to evaluate the role of Wnt/ß-catenin signaling during late stages of intestinal adaptation in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into two groups: sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's digital gene expression analysis was used to determine Wnt/ß-catenin signaling gene expression profiling. Twelve Wnt/ß-catenin-related genes and ß-catenin protein expression were determined using real-time PCR, western blotting and immunohistochemistry. RESULTS: From the total number of 20,000 probes, 20 genes related to Wnt/ß-catenin signaling were investigated. From these genes, seven genes were found to be up-regulated and eight genes to be down-regulated in SBS vs. sham animals with a relative change in gene expression level of 20 % or more. From 12 genes determined by real-time PCR, nine genes were down-regulated in SBS rats compared to control animals including target gene c-Myc. SBS rats also showed a significant decrease in ß-catenin protein compared to control animals. CONCLUSION: Two weeks following massive bowel resection in rats, Wnt/ß-catenin signaling pathway is inhibited. In addition, it appears that cell differentiation rather than proliferation is most important in the late stages of intestinal adaptation.

Dietary supplementation with vitamin D stimulates intestinal epithelial cell turnover after massive small bowel resection in rats.

PURPOSE: While the endocrine action of the active metabolite 1,25-dihydroxyvitamin D (VtD) has been well characterized in relation to the maintenance of plasma calcium and phosphate homeostasis through regulation of intestinal absorption, recent research has focused on its autocrine and/or paracrine activities. Such activities have been best characterized in intestine, where VtD regulates cell differentiation and maturation. The purpose of this study was to evaluate the effect of VtD on enterocyte turnover in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into four groups: sham rats underwent bowel transection, sham-VtD rats underwent bowel transection and were treated oral VtD, SBS rats underwent a 75 % bowel resection, and SBS-VtD rats underwent bowel resection and were treated with VtD. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's digital gene expression (DGE) analysis was used to determine VtD pathway-related gene expression profiling. VtD receptor (VDR) and its promoter, Bax and Bcl-2 mRNA expression were determined using real-time PCR. Western blotting was used to determine p-ERK, Bax and ß-catenin protein levels. RESULTS: From the total of 20,000 probes, 11 genes related to VtD signaling were investigated. Of these genes, five were found to be up-regulated in SBS versus sham animals with a relative change in gene expression level of 20 %, five remained unchanged, and one was down-regulated. VtD treatment in sham and SBS rats resulted in significant up-regulation of the VDR gene and its promoter's expression. SBS-VtD rats demonstrated a significant increase in all intestinal mucosal parameters compared to SBS animals. A significant increase in cell proliferation in SBS-VtD rats was accompanied by increased ß-catenin protein levels. A significant decrease in cell apoptosis in this group was correlated with lower Bax/Bcl-2 mRNA and protein levels. CONCLUSION: In a rat model of SBS, dietary supplementation with VtD stimulates enterocyte turnover, which correlates with up-regulated VtD receptor expression in the remaining small intestine.

Methotrexate induces germ cell apoptosis and impairs spermatogenesis in a rat.

PURPOSE: The primary toxic effects of methotrexate (MTX) are myelosuppression and/or intestinal mucositis. The objective of the present study is to investigate the effect of MTX on germ cell apoptosis and spermatogenesis in a rat. METHODS: Male Sprague-Dawley rats were divided into three experimental groups: control rats treated with vehicle; MTX-2 rats treated with one dose (20 µg/kg) of MTX given IP and killed on the second day; and MTX rats treated with IP MTX (20 µg/kg) and killed on day 4. Johnsen's criteria and the number of germinal cell layers in the testes were used to categorize the spermatogenesis. TUNEL assay was used to determine germ cell apoptosis. Western blotting was used to determine Bax and Bcl-2 protein levels. Statistical analysis was performed using the non-parametric Kruskal-Wallis ANOVA test, with p less than 0.05 considered statistically significant. RESULTS: On day 2, MTX-treated animals demonstrated minimal changes in the histological parameters of spermatogenesis, but germ cell apoptosis increased significantly (threefold increase, p = 0.002) compared to control rats. On day 4, MTX-treated rats demonstrated a trend toward a decrease in germ cell apoptosis, compared to day 2, and showed histological signs of impaired spermatogenesis (decreased number of germ cell layers and Johnsen's criteria). A significant increase in cell apoptosis in MTX-treated rats was correlated with higher Bax/Bcl-2 protein levels. CONCLUSIONS: MTX induced germ cell apoptosis and impaired spermatogenesis in rat testes.

The effect of combined spinal-epidural anesthesia versus general anesthesia on the recovery time of intestinal function in young infants undergoing intestinal surgery: a randomized, prospective, controlled trial.

STUDY OBJECTIVE: To assess the rate of restoration of gastrointestinal (GI) function following combined spinal-epidural (CSE) anesthesia compared with general anesthesia in young infants undergoing elective intestinal surgery. DESIGN: Prospective, randomized, controlled study. SETTING: Operating room and neonatal intensive care unit of a university hospital. SUBJECTS: 50 young infants undergoing elective intestinal surgery. INTERVENTIONS AND MEASUREMENTS: 50 young infants were randomly allocated to two groups of 25 patients each, a general anesthesia group and a CSE anesthesia group. The two groups were further divided into two subgroups according to whether the surgical procedure was performed on the small or large intestine. The main outcome of this study was to measure the recovery times of GI function by determining the time to the first postoperative stool, duration of nasogastric feeding, and onset time of full enteral nutrition. The secondary outcome was to detect adverse events postoperatively. MAIN RESULTS: Recovery of intestinal function was faster (P < 0.0001) and the frequencies of postoperative abdominal distension and pneumonia were less (P < 0.04) in infants who were anesthetized with CSE anesthesia than general anesthesia. CONCLUSIONS: Combined spinal-epidural anesthesia leads to faster restoration of GI function while reducing adverse events in infants who require elective intestinal surgery.

TGF-ß affects enterocyte turnover in correlation with TGF-ß receptor expression after massive small bowel resection.

OBJECTIVES: In the present study, we evaluated the effect of transforming growth factor-beta 2 (TGF-ß2)-enriched diet on enterocyte turnover and correlated it with TGF-ß2 receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS). METHODS: CaCo-2 cells were incubated with increasing concentrations of TGF-ß2. Alamar Blue reduction test was used for investigation of cell viability and evaluation of cell apoptosis was assessed by flow cytometry. Male rats were divided into 4 groups: Sham rats underwent bowel transection, Sham TGF-ß rats were treated with diet enriched with TGF-ß2, SBS rats underwent a 75% bowel resection, and SBS TGF-ß rats were fed a diet enriched with TGF-ß2 after bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. TGF-ß2r expression in villus tips, lateral villi and crypts was assessed by immunohistochemistry. The effect of TGF-ß2 on enterocyte turnover for each compartment was evaluated in correlation with TGF-ß2r expression. RESULTS: Incubation of CaCo-2 cells with TGF-ß2 resulted in a significant decrease in cell viability and increased cell apoptosis. TGF-ß2r expression in crypts increased in SBS rats (vs sham) and was accompanied by decreased cell proliferation and increased cell apoptosis following TGF-ß2 administration. A significant decrease in TGF-ß2r expression at villous tips in SBS rats was accompanied by a decreased cell apoptosis in this compartment following exposure to TGF-ß2-enriched diet. CONCLUSIONS: In a rat model of SBS, the inhibiting effect of TGF-ß2 on enterocyte turnover correlates with TGF-ß2 receptor expression along the villus-crypt axis.

Improved outcomes in paediatric anaesthesia: contributing factors.

PURPOSE: To discuss developments in paediatric anaesthesia and explore the factors which have contributed to improved anaesthetic-related patient outcomes. METHODS: Narrative review of findings in the literature retrieved from MEDLINE/Pubmed and manual search. RESULTS: Adverse perioperative outcomes related to anaesthesia have been extensively debated over the past few decades, with studies implicating factors such as major human error and equipment failure. Case series and event registries have enlightened physicians on sources of error and patient risk factors such as extremes of age, comorbidity and emergent circumstances. Anaesthetic-related deaths in children fell from 6.4 per 10,000 anaesthetics in the early 1950s to as low as 0.1 per 10,000 anaesthetics by the end of the century. Advances in anaesthetic agents, techniques, monitoring technologies and training programmes in paediatric anaesthesia play a vital role in driving this downward trend. CONCLUSION: Despite substantial progress, there is still much room for improvement in areas such as adverse-event reporting, anaesthetic-related risk and late neurocognitive outcomes. Systematic reviews comparing paediatric patient outcomes after neuroaxial block versus general anaesthesia are currently unavailable. The future of paediatric anaesthesia will most likely be influenced by much-needed large prospective studies, which can provide further insight into patient safety and service delivery.

PDGF-α stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat.

Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at euthanasia. Illumina's Digital Gene Expression analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined by real-time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax, and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared with sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height, and crypt depth in jejunum and ileum compared with SBS animals. PDGF-α receptor expression in crypts increased in SBS rats (vs. sham) and was accompanied by an increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with upregulated PDGF-α receptor expression in the remaining small intestine.

Effect of alpha-naphthylisothiocyanate-induced liver injury on intestinal adaptation in a rat model of short bowel syndrome.

BACKGROUND/PURPOSE: Progressive hyperbilirubinemia and end-stage liver failure are among the most serious complications of short bowel syndrome (SBS), representing the principle cause of death in a majority of fatal cases. In the current study, we examined the effects of alpha-naphthylisothiocyanate (ANIT)-induced liver injury on intestinal adaptation in a rat model of SBS. METHODS: Male rats were divided into four groups: Sham rats underwent bowel transection (n = 8), Sham liver-injury rats underwent bowel transection and IP injection of ANIT (100 mg/kg, n = 8), SBS rats underwent a 75% bowel resection, and SBS-ANIT rats underwent bowel resection and liver injury similar to group sham-ANIT (n = 8). Fourteen days after intervention, liver biopsies and intestinal samples were obtained and evaluated for liver damage and measures of intestinal adaptation. Real time PCR and Western blotting were used to determine the level of bax and bcl-2 mRNA and protein, and p-ERK protein levels. Statistical analysis was performed using the one-way ANOVA test, with p < 0.05 considered statistically significant. RESULTS: All ANIT-treated animals exhibited histological evidence of liver damage that was associated with the expansion of atypical ductal proliferation near the periportal areas, intense neutrophil infiltration in the liver, increased mitotic activity, Kupfer cells hyperplasia and fatty liver degeneration. ANIT-induced liver damage in bowel resected animals was associated with a significant decrease in all parameters of intestinal adaptation including bowel and mucosal weight in jejunum (twofold decrease) and ileum (twofold decrease), mucosal DNA in jejunum (fourfold decrease), mucosal protein in jejunum (threefold decrease) and ileum (threefold decrease), villus height in jejunum (38%) and ileum (34%), and crypt depth in jejunum (24%) and ileum (30%) compared to SBS animals. Both Sham-ANIT and SBS-ANIT rats demonstrated decreased enterocyte proliferation rates that were accompanied by decreased p-ERK protein levels. Lower apoptotic rates in jejunum (40%) and ileum (52%) in SBS-ANIT rats (vs. SBS) coincided with decreased bax mRNA and protein levels. CONCLUSIONS: In a rat model of SBS, ANIT-induced liver injury was associated with decreased enterocyte proliferation and inhibited intestinal adaptation.

Oral insulin stimulates intestinal epithelial cell turnover following massive small bowel resection in a rat and a cell culture model.

PURPOSE: We have recently reported that oral insulin (OI) stimulates intestinal adaptation after bowel resection and that OI enhances enterocyte turnover in correlation with insulin receptor expression along the villus-crypt axis. The purpose of the present study was to evaluate the effect of OI on intestinal epithelial cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS) and in a cell culture model. METHODS: Caco-2 cells were incubated with increasing concentrations of insulin. Cell proliferation and apoptosis were determined by FACS cytometry. Cell viability was investigated using the Alamar Blue technique. Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the third postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real time PCR was used to determine the level of bax and bcl-2 mRNA and western blotting was used to determine bax, bcl-2, p-ERK and AKT protein levels. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant. RESULTS: Treatment of Caco-2 cells with insulin resulted in a significant increase in cell proliferation (twofold increase after 24 h and 37% increase after 48 h) and cell viability (in a dose-dependent manner), but did not change cell apoptosis. In a rat model of SBS, treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Elevated cell proliferation rate in insulin treated rats was accompanied by elevated AKT and p-ERK protein levels. Decreased cell apoptosis in SBS-INS rats corresponded with a decreased bax/bcl-2 ratio. CONCLUSIONS: Oral insulin stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat model of SBS and a cell culture model.

Parenteral omega-3 fatty acids (Omegaven) modulate intestinal recovery after intestinal ischemia-reperfusion in a rat model.

BACKGROUND/PURPOSE: Fatty acids from fish oil (omega-3 polyunsaturated fatty acids, 3PUFAs) are emerging as powerful yet safe disease-modifying nutrients and are protective in severe critical care conditions including ischemia-reperfusion (IR) injury. The purpose of the present study was to examine the effects of 3PUFAs on intestinal structural changes, enterocyte proliferation, and apoptosis after intestinal IR in a rat. METHODS: Male rats were divided into three experimental groups: sham rats underwent laparotomy, IR rats underwent occlusion of both superior mesenteric artery and portal vein for 30 minutes followed by 48 hours of reperfusion, and 3PUFA-treated IR (IR-3PUFA) rats underwent IR and were treated with Omegaven (Fresenius Kabi, Bad Homburg, Germany) given intraperitoneally at a dose of 1 mL twice a day. Intestinal structural changes (Park injury score, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, cell proliferation, and apoptosis) were determined 48 hours after IR. Real-time polymerase chain reaction (PCR) was used to determine the level of bax and bcl-2 messenger RNA. RESULTS: A significant decrease in bowel and mucosal weight was observed in the ileum of untreated IR rats compared with sham animals. Forty-eight hours after IR, cell apoptosis remained increased in the jejunum and ileum, which coincided with increased bax/bcl-2 ratio. Cell proliferation was increased 48 hours after IR, suggesting tissue repair. Treatment with Omegaven resulted in a significant increase in bowel and mucosal weight in the jejunum and ileum, villus height in the jejunum and ileum, and crypt depth in the jejunum compared with untreated IR animals. IR-3PUFA rats also demonstrated a significantly lower Park injury score in the jejunum and ileum as well as a lower apoptotic index in the ileum compared with untreated IR animals. CONCLUSIONS: Parenteral Omegaven administration decreases the intestinal mucosal injury and inhibits enterocyte apoptosis after intestinal IR in a rat.

The postoperative occurrence of cardio-respiratory adverse events in small infants undergoing gastrointestinal surgery: a prospective comparison of general anesthesia and combined spinal-epidural anesthesia.

INTRODUCTION: This study was designed to compare the occurrences of postoperative cardio-respiratory adverse events during an 8-day follow-up period in the neonatal intensive care unit in small infants who underwent elective gastrointestinal surgery under general and combined spinal epidural anesthesia. METHODS: Fifty infants who underwent elective primary gastrointestinal surgery were randomly divided into two anesthetic techniques. General anesthesia (25 patients) and combined spinal-epidural anesthesia (25 patients). The frequency and types of postoperative cardiovascular and respiratory adverse events in the two groups were recorded and compared during an 8-day follow-up period in the neonatal intensive care unit. RESULTS: The total number of postoperative respiratory adverse events and the number of infants who experienced at least one respiratory adverse event were statistically more in infants anesthetised by general anesthesia than in infants who were anesthetised by combined spinal-epidural anesthesia, respectively (p < 0.0001) and (RR = 2.5; 95% CI 1.2-5.3). There were significantly more cardiovascular adverse events in the general anesthesia infants than in the combined spinal-epidural anesthesia (p = 0.005). These adverse cardiovascular events were also more resistant to treatment in the general anesthesia infants than in the combined spinal-epidural anesthesia infants (p = 0.001). CONCLUSION: Compared to general anesthesia, combined spinal-epidural anesthesia reduces the frequency of postoperative respiratory adverse events and improves the postoperative cardiovascular stability in small infants who undergo elective gastrointestinal surgery.

Effect of oral insulin on diabetes-induced intestinal mucosal growth in rats.

BACKGROUND: To evaluate the intestinal response to the induction of diabetes and to oral insulin (OI) administration in a rat. METHODS: Male Sprague-Dawley rats were divided into four experimental groups: control rats, CONTR-INS rats that were treated with OI given in drinking water for 7 days, diabetic rats that were injected with one dose of streptozotocin, and diabetic rats treated with OI. Intestinal structural changes, enterocyte proliferation and enterocyte apoptosis, bax and bcl-2 mRNA and protein levels, insulin receptor expression and ERK protein levels were determined at sacrifice. A one-way ANOVA for comparison, followed by Tukey's test for pair-wise comparison, were used for statistical analysis. RESULTS: Induction of diabetes resulted in a significant increase in bowel and mucosal weight (P < 0.05), mucosal protein (P < 0.05), villus height and crypt depth in jejunum and ileum (P < 0.05), and mucosal DNA in ileum (P < 0.05) (vs. control animals). Diabetes also enhances ERK-induced cell proliferation (P < 0.05) and concomitant bax/bcl-2 induced cell apoptosis (P < 0.05). Treatment of diabetic rats with OI resulted in a significant decrease in jejunal protein content (P < 0.05), jejunal and ileal villus height (P < 0.05), and jejunal crypt depth (P < 0.05), as well as an inhibition of ERK-related cell proliferation in ileum (P < 0.05). Expression of insulin receptor was down-regulated following OI administration in both control and diabetic animals. CONCLUSIONS: Experimental STZ-induced diabetes causes intestinal mucosal growth and enhances enterocyte turnover in a rat model. OI administration diminishes diabetes-accelerated cell turnover and diabetes-induced mucosal hyperplasia.

Nutritional supplementation with transforming growth factor-beta inhibits intestinal adaptation after massive small bowel resection in a rat.

INTRODUCTION: Transforming growth factor beta (TGF-ß) has been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal and epithelial-immune cell interaction. In the present study, we evaluated the effect of TGF-ß2-enriched polymeric diet (Modulen) on enterocyte turnover in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into four groups: Sham rats and Sham-TGF-ß rats underwent bowel transection, and were treated with TGF-ß from the 4th postoperative day, SBS rats underwent a 75% bowel resection, and SBS-TGF-ß rats underwent bowel resection and were treated with TGF-ß-enriched diet similar to Group B. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real-time PCR was used to determine Bax and Bcl-2 mRNA expression. RESULTS: Treatment of SBS animals with TGF-ß2 supplemented diet led to a significant decrease (vs. SBS rats) in bowel weight in ileum (18%, P < 0.05), mucosal DNA content in jejunum (threefold decrease, P < 0.05) and ileum (2.5-fold decrease, P < 0.05), and mucosal protein in jejunum (twofold decrease, P < 0.05) compared to SBS-untreated animals (Group B). Treatment with TGF-ß resulted in a mild decrease in enterocyte proliferation in jejunum (25%, P < 0.05) and ileum (18%, P < 0.05). A decreased cell apoptosis in the SBS-TGF-ß group was accompanied by a decreased Bax and increased Bcl-2 mRNA expression. CONCLUSIONS: In a rat model of SBS, dietary TGF-ß inhibits intestinal adaptation. Decreased enterocyte proliferation is responsible for this effect.

Oral insulin stimulates intestinal epithelial cell turnover in correlation with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome.

PURPOSE: It has been reported that oral insulin (OI) has a trophic effect on intestinal mucosa. In the present study, we evaluated the effect of OI on enterocyte turnover and correlated it with insulin-receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the fourth postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real-time PCR was used to determine the level of insulin receptor-beta (IRB) mRNA. Insulin-receptor expression along the villus-crypt axis (villus tips, lateral villi and crypts) was assessed by immunohistochemistry. The effect of OI on cell turnover for each compartment was evaluated in correlation with the receptor expression. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant. RESULTS: Treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Insulin-receptor expression in crypts significantly increased in SBS rats (vs. Sham rats) and was accompanied by a significant increase in enterocyte proliferation following OI administration. A significant increase in insulin-receptor expression at the tip of the villous and in the lateral villous in SBS rats (vs. Sham) was accompanied by decreased cell apoptosis in these compartments following treatment with OI. CONCLUSIONS: In a rat model of SBS, OI enhances enterocyte turnover and stimulates intestinal adaptation. The stimulating effect of insulin on enterocyte turnover correlates with insulin-receptor expression along the villus-crypt axis.

Leptin affects intestinal epithelial cell turnover in correlation with leptin receptor expression along the villus-crypt axis after massive small bowel resection in a rat.

In this study, we examine the responsiveness of intestinal epithelial cell turnover to leptin (LEP) in correlation with leptin receptor (LEPr) expression along the villus-crypt axis in a rat with short bowel syndrome (SBS). Adult rats underwent either a 75% intestinal resection or a transection. SBS-LEP rats underwent bowel resection and were treated with LEP starting from the fourth postoperative day. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined at sacrifice. RT-PCR technique was used to determine Bax and Bcl-2 gene expression in ileal mucosa. Villus tips, lateral villi, and crypts were separated using laser capture microdissection. LEPr expression for each compartment was assessed by quantitative real-time PCR (Taqman). Treatment with LEP significantly stimulated all parameters of adaptation. LEPr expression in crypts significantly increased in SBS rats (vs Sham rats) and was accompanied by a significant increase in enterocyte proliferation and decreased apoptosis after LEP administration. A significant increase in LEPr expression at the tip of the villus in SBS rats was accompanied by decreased cell apoptosis. In conclusion LEP accelerated enterocyte turnover and stimulated intestinal adaptation. The effect of LEP on enterocyte proliferation and enterocyte apoptosis correlated with receptor expression along the villus-crypt axis.

Involvement of the bax and bcl-2 system in the induction of germ cell apoptosis is correlated with the time of reperfusion after testicular ischemia in a rat model.

The objective of this study was to examine the relationship between time of reperfusion and bax/bcl-2-dependent germ cell apoptosis after testicular ischemia-reperfusion injury in the rat. In ischemic testis, bax/bcl-2 ratio did not change significantly, and the elevation of germ cell apoptosis was not marked; in the contralateral testis, germ cell apoptosis increased after 6 hours of reperfusion, achieved statistical significance after 24 hours, and decreased after 72 hours of reperfusion and was initiated by decreased bcl-2 messenger RNA levels and elevated bax/bcl-2 ratio within the first 6 hours of reperfusion.

Bilirubin impairs intestinal regrowth following massive small bowel resection in a rat model.

OBJECTIVES: The purpose of the present study was to evaluate the effects of exogenous bilirubin on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into 5 experimental groups: Sham rats underwent bowel transection and reanastomosis, sham multiple doses of bilirubin (MDB) rats underwent bowel transection and were treated with bilirubin, SBS rats underwent a 75% small bowel resection, SBS-SDB (single dose bilirubin) rats underwent a bowel resection and were treated with a single dose of bilirubin, and SBS-MDB underwent a bowel resection and were treated with 3 doses of bilirubin. Bilirubin was administered intraperitoneally from the 7th day through the 14th day postoperatively. Serum total bilirubin concentration over time was evaluated in 5 SBS-SDB rats following a single intraperitoneal dose. Total bilirubin, alanine aminotransferase, and aspartate aminotransferase in serum and parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15. RESULTS: SBS-SDB and SBS-MDB animals demonstrated lower ileal bowel and mucosal weights, jejunal mucosal DNA and ileal mucosal protein, and jejunal and ileal villus height and crypt depth (vs SBS animals). Bilirubin-treated rats showed a lower apoptotic index in jejunum and ileum and a trend toward an increase in cell proliferation in jejunum and ileum (vs SBS group). CONCLUSIONS: In a rat model of SBS, exogenous bilirubin inhibits structural intestinal adaptation. Increased cell proliferation and decreased apoptosis may be considered adaptive mechanisms that maintain cell mass.