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.

Reoperative surgery for Hirschsprung disease

Despite most children undergoing a successful pull through for Hirschsprung disease, a small portion of children are left with persistent stooling issues. Most of these stooling issues can be addressed by nonoperative approaches. However, in a small group of remaining children, a reoperation may be necessary. Most children who may need a redo pull-through procedure may have a persistent area of aganglionosis, unremitting enterocolitis, or a torsion or stricture of the pull-through segment. Each of these influences the approach the surgeon must take to correct the presenting problem. The chapter details the diagnostic approach as well as the operative techniques, which best deal with each of these complications.

Coran A, Sukhotnik I. Dietary transforming growth factor-beta 2 (TGF-β2) supplementation reduces methotrexate-induced intestinal mucosal injury in a rat

BACKGROUND/AIMS

Dietary supplementation with transforming growth factor-beta (TGF-β) has been proven to minimize intestinal damage and facilitate regeneration after mucosal injury. In the present study, we evaluated the effects of oral TGF-β2 supplementation on intestinal structural changes, enterocyte proliferation and apoptosis following methotrexate (MTX)-induced intestinal damage in a rat and in a cell culture model.

METHODS

Caco-2 cells were treated with MTX and were incubated with increasing concentrations of TGF-β2. Cell apoptosis was assessed using FACS analysis by annexin staining and cell viability was monitored using Trypan Blue assay. Male rats were divided into four experimental groups: Control rats, CONTR- TGF-β rats were treated with diet enriched with TGF-β2, MTX rats were treated with a single dose of methotrexate, and MTX- TGF-β rats were treated with diet enriched with TGF-β2. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined at sacrifice. Real Time PCR and Western blot were used to determine bax and bcl-2 mRNA, p-ERK, β-catenin, IL-1B and bax protein expression.

RESULTS

Treatment of MTX-pretreated Caco-2 cells with TGF-B2 resulted in increased cell viability and decreased cell apoptosis. Treatment of MTX-rats with TGF-β2 resulted in a significant increase in bowel and mucosal weight, DNA and protein content, villus-height (ileum), crypt-depth (jejunum), decreased intestinal-injury score, decreased level of apoptosis and increased cell proliferation in jejunum and ileum compared to the untreated MTX group. MTX-TGF-β2 rats demonstrated a lower bax mRNA and protein levels as well as increased bcl-2 mRNA levels in jejunum and ileum compared to MTX group. Treatment with TGF-β2 also led to increased pERK, IL-1B and β-catenin protein levels in intestinal mucosa.

CONCLUSIONS

Treatment with TGF-β2 prevents mucosal-injury, enhances p-ERK and β-catenin induced enterocyte proliferation, inhibits enterocyte apoptosis and improves intestinal recovery following MTX-induced intestinal-mucositis in rats.

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.

The 100 most-cited articles in Pediatric Surgery International

PURPOSE

Citation analysis within specific journals and subject areas has become a popular method to assess the impact of a journal, article or author. To date, only a few evaluations of citation reports have been published in the field of pediatric surgery. Twenty-six years after its inception, Pediatric Surgery International (PSI) is a firmly established journal in pediatric surgery. The aim of this study was to identify, analyze and categorize the characteristics of the 100 most-cited articles published in PSI since its founding in 1986.

METHODS

The Web of Knowledge(SM), hosted by the Institute for Scientific Information, was searched with the all-database function for the 100 most-cited articles in PSI published from 1986 to the present. Each article was reviewed and the following parameters were recorded: number of citations, type of article, topic, year of publication, country of origin, institution and authorship.

RESULTS

Between 1986 and 2012, 4,907 articles were published in PSI and 3,608 (73.53 %) of these were cited at least once. The 100 most-cited articles received a total of 3,309 citations with a mean of 33.09 (range 24-81). These articles were published between 1987 and 2007, with 73 articles published after 1997. Leading countries were USA (n = 15), Australia (n = 12), UK (n = 9) and Ireland (n = 9). Articles were categorized as followed: 92 original articles, 5 reviews and 3 case reports. 84 articles derived from clinical research and 16 derived from basic science. The most prolific authors were from 7 different institutions and published 37 articles, which received 1,213 (36.66 %) citations.

CONCLUSION

The 100 most-cited articles published in PSI were predominately original articles from English-speaking countries dealing with clinical topics. This analysis may be of value to the editorial board and authors by providing some insights into what types of manuscripts appear to be of interest to the reading audience of PSI.

Dietary L-arginine supplementation reduces Methotrexate-induced intestinal mucosal injury in rat

Background

Arginine (ARG) and nitric oxide maintain the mucosal integrity of the intestine in various intestinal disorders. In the present study, we evaluated the effects of oral ARG supplementation on intestinal structural changes, enterocyte proliferation and apoptosis following methotrexate (MTX)-induced intestinal damage in a rat.

Methods

Male rats were divided into four experimental groups: Control rats, CONTR-ARG rats, were treated with oral ARG given in drinking water 72 hours before and 72 hours following vehicle injection, MTX rats were treated with a single dose of methotrexate, and MTX-ARG rats were treated with oral ARG following injection of MTX. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined 72 hours following MTX injection. RT-PCR was used to determine bax and bcl-2 mRNA expression.

Results

MTX-ARG rats demonstrated greater jejunal and ileal bowel weight, greater ileal mucosal weight, greater ileal mucosal DNA and protein levels, greater villus height in jejunum and ileum and crypt depth in ileum, compared to MTX animals. A significant decrease in enterocyte apoptosis in the ileum of MTX-ARG rats (vs MTX) was accompanied by decreased bax mRNA and protein expression and increased bcl-2 protein levels.

Conclusions

Treatment with oral ARG prevents mucosal injury and improves intestinal recovery following MTX- injury in the 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.

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.

Parenteral but not enteral omega-3 fatty acids (Omegaven) modulate intestinal regrowth after massive small bowel resection in rats

BACKGROUND

The purpose of the present study was to evaluate the effects of ω-3 fatty acids (Omegaven) on early intestinal adaptation in rats with short bowel syndrome (SBS).

METHODS

Male Sprague-Dawley rats were randomly assigned to 1 of 4 groups: sham rats underwent bowel transection; SBS rats underwent 75% bowel resection; SBS-O ω-3 rats underwent bowel resection and were treated with oral Omegaven given by gavage; and SBS-I ω-3 rats underwent bowel resection and were treated with Omegaven given intraperitoneally. Rats were killed on day 14. Parameters of intestinal adaptation (bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depths, cell proliferation and apoptosis) were determined at time of death. Real-time polymerase chain reaction was used to determine the level of Bax and Bcl-2 messenger RNA (mRNA). Statistical analysis was performed using Kruskal-Wallis test followed by post hoc test, with P < .05 considered statistically significant.

RESULTS

Oral ω-3 supplementation did not significantly change intestinal regrowth. In contrast, parenteral ω-3 in rats that underwent resection resulted in higher bowel and mucosal weights, mucosal DNA and protein in ileum, villus height in ileum, crypt depth in jejunum and ileum, and greater rates of cell proliferation in jejunum and ileum compared with SBS animals. The initial decreased levels of apoptosis corresponded with the early decrease in Bax and increase in Bcl-2 mRNA levels.

CONCLUSIONS

Parenteral but not enteral Omegaven augments and accelerates structural bowel adaptation in a rat model of SBS. Increased cell proliferation and decreased apoptosis reflect increased cell turnover in Omegaven-treated animals.

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

INTRODUCTION

Transforming growth factor beta (TGF-β) 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-β2-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-β rats underwent bowel transection, and were treated with TGF-β from the 4th postoperative day, SBS rats underwent a 75% bowel resection, and SBS-TGF-β rats underwent bowel resection and were treated with TGF-β-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-β2 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-β 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-β group was accompanied by a decreased Bax and increased Bcl-2 mRNA expression.

CONCLUSIONS

In a rat model of SBS, dietary TGF-β inhibits intestinal adaptation. Decreased enterocyte proliferation is responsible for this effect.

The role of fiberoptic endoscopy in the evaluation and management of long gap isolated esophageal atresia

Accurate measurement of gap length is useful for operative planning in cases of esophageal atresia (EA) without distal fistula. This paper demonstrates how fiberoptic endoscopy of the distal esophagus enables measurement of the gap in the case of isolated EA, and compares other commonly practiced techniques.

Gastric transposition in infants and children

The loss of esophageal length in long-gap esophageal atresia or obliteration of the esophageal lumen due to stricture may require major operative reconstruction. A number of procedures have been developed to allow anatomic replacement of the esophagus. The gastric transposition requires a single cervical anastomosis and uses a gastric conduit with excellent blood supply. This review illustrates the procedure and discusses its indications, planning, and outcome.

Congenital esophageal stenosis: the differential diagnosis and management

Congenital esophageal stenosis (CES) is a rare congenital abnormality that is difficult to diagnose and often masquerades as other types of structural esophageal disease. We report three cases of CES with different presenting symptoms. We advocate for balloon dilation as the preferred first approach to therapeutic intervention. CES is an important clinical entity in the evaluation of pediatric esophageal disorders and should be suspected in young infants with dysphagia.

Effect of simvastatin on intestinal recovery following gut ischemia-reperfusion injury in a rat

BACKGROUND

Pleiotropic (lipid lowering-independent) effects of statins are attributed to their antiinflammatory, antioxidant, and/or vascular actions. Extensive studies in various experimental models have established that pretreatment with simvastatin significantly protects heart and kidney injured by ischemia-reperfusion (IR). The purpose of the present study was to examine the effect of simvastatin on intestinal recovery and enterocyte turnover after intestinal IR injury in rats.

METHODS

Male Sprague-Dawley rats were divided into three experimental groups: (1) sham rats underwent laparotomy, (2) IR-rats underwent occlusion of both superior mesenteric artery and portal vein for 30 min followed by 48 h of reperfusion, and (3) IR-SIM rats underwent IR and were treated with oral simvastatin (10 mg/kg) given by gavage immediately before and 24 h after operation. Intestinal structural changes, Park's injury score, enterocyte proliferation and enterocyte apoptosis were determined 24 h following IR. A non-parametric Kruskal-Wallis ANOVA test was used for statistical analysis with P less than 0.05 considered statistically significant.

RESULTS

Treatment with simvastatin resulted in a significant increase in bowel and mucosal weight in ileum, villus height and crypt depth in jejunum and ileum compared to IR animals. IR-SIM rats had also a significantly lower intestinal injury score as well as lower apoptotic index in jejunum and ileum compared to IR animals.

CONCLUSIONS

Treatment with simvastatin prevents gut mucosal damage and inhibits programmed cell death following intestinal IR in a rat.

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.

Possible importance of increased intra-abdominal pressure for the development of necrotizing enterocolitis

BACKGROUND/PURPOSE

Despite extensive clinical and laboratory investigations, many aspects of the pathogenesis of necrotizing enterocolitis (NEC) remain unclear. In the present work we describe 5 neonates with NEC in whom intra-abdominal pressure (IAP) was measured to investigate the potential role of abdominal compartment syndrome (ACS) in the development of NEC and to correlate the severity of NEC with the value of IAP.

METHODS

IAP pressure was determined in two groups - Group A consisting of five patients without NEC (Control) and Group B consisting of five patients who developed NEC - by measuring the urinary bladder pressure (UBP). The correlation between increased IAP and severity of NEC, complications of NEC and indications for surgery was investigated.

RESULTS

In four patients from Group B, the general condition deteriorated despite aggressive supportive treatment, and a laparotomy was performed. These neonates demonstrated a significant increase (compared to Control patients) in UBP (9.0+/-2.5 vs. 4.8+/-1.4 mmHg, p=0.001), which increased progressively with exacerbation of NEC and reached a peak value of 13.3+/-2.4 mmHg before operation. The elevated IAP was accompanied by hemodynamic instability in all patients, respiratory instability in 3 patients and decreased urinary output in one patient. One patient remained unstable and died 6 h after operation. In the fifth patient from Group B, intestinal obstruction developed two weeks after NEC and did not result in increased IAP.

CONCLUSIONS

Our results suggest that IAP is associated with an exacerbation of NEC. Thus, this study provides further information which may improve our understanding of the pathogenic process of NEC.

Effect of oral glutamine on enterocyte turnover during methotrexate-induced mucositis in rats

BACKGROUND/AIMS

The objective of this study was to evaluate the effects of oral glutamine in preventing intestinal mucosal damage caused by methotrexate (MTX) in rats.

METHODS

Male Sprague-Dawley rats were divided into 3 experimental groups: control rats, rats treated intraperitoneally with MTX (MTX rats) and rats treated with oral glutamine in the drinking water (2%) 72 h following intraperitoneal injection of a single dose of MTX (MTX-glutamine rats). Intestinal mucosal damage (Park's injury score), mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined 72 h following MTX injection. RT-PCR was used to determine Bax and Bcl-2 mRNA expression.

RESULTS

MTX-glutamine rats demonstrated greater jejunal and ileal mucosal weight and mucosal DNA, greater ileal villus height and crypt depth, and a greater index of proliferation in the jejunum and ileum compared to MTX animals. A significant decrease in enterocyte apoptosis in the ileum of MTX-glutamine rats (vs. MTX) was accompanied by decreased Bax and increased Bcl-2 mRNA expression.

CONCLUSIONS

Treatment with oral glutamine prevents mucosal injury and improves intestinal recovery following MTX injury in the rat.

A prospective, randomized comparison of skin adhesive and subcuticular suture for closure of pediatric hernia incisions: cost and cosmetic considerations

PURPOSE

In this study, we compared the skin adhesive 2-octylcyanoacrylate to subcuticular suture for closure of pediatric inguinal hernia incisions to determine if skin adhesive improves wound cosmesis, shortens skin closure time, and lowers operative costs.

METHODS

We prospectively randomized 134 children undergoing inguinal herniorrhaphy at our institution to have skin closure with either skin adhesive (n = 64) or subcuticular closure (n = 70). Data collected included age, sex, weight, type of operation, total operative time, and skin closure time. Digital photographs of healing incisions were taken at the 6-week postoperative visit. The operating surgeon assessed cosmetic outcome of incisions using a previously validated visual analog scale, as well as an ordinate scale. A blinded assessment of cosmetic outcome was then performed by an independent surgeon comparing these photographs to the visual analog scale. Operating room time and resource use (ie, costs) relative to the skin closure were assessed. Comparisons between groups were done using Student's t tests and chi(2) tests.

RESULTS

Children enrolled in the study had a mean +/- SE age of 3.7 +/- 0.3 years and weighed 16 +/- 0.8 kg. Patients were predominantly male (82%). Patients underwent 1 of 3 types of open hernia repair as follows: unilateral herniorrhaphy without peritoneoscopy (n = 41; 31%), unilateral herniorrhaphy with peritoneoscopy (n = 55; 41%), and bilateral herniorrhaphy (n = 38; 28%). Skin closure time was significantly shorter in the skin adhesive group (adhesive = 1.4 +/- 0.8 minutes vs suture = 2.4 +/- 1.1 minutes; P = .001). Mean wound cosmesis scores based on the visual analog scale were similar between groups (adhesive = 78 +/- 21; suture=78 +/- 18; P = .50). Material costs related to herniorrhaphy were higher for skin adhesive (adhesive = $22.63 vs suture = $11.70; P < .001), whereas operating room time costs for adhesive skin closure were lower (adhesive = $9.33 +/- 5.33 vs suture = $16.00 +/- 7.33; P < .001). Except for a 7% incidence of erythema in both groups, there were no complications encountered.

CONCLUSIONS

There is no difference in cosmetic outcome between skin adhesive and suture closure in pediatric inguinal herniorrhaphy. Material costs are increased because of the high cost of adhesive relative to suture. This is partially offset, however, by the cost savings from reduction in operating room time.

Outcomes in pediatric patients undergoing straight vs J pouch ileoanal anastomosis: a multicenter analysis

BACKGROUND

Outcomes remain controversial for patients undergoing straight (SIAA) vs J pouch (JPAA) ileoanal anastomosis, particularly in children where fewer such cases are performed. Our 3 centers have had extensive experience with both techniques. Thus, we had the unique opportunity to compare outcomes within the same centers.

METHODS

We retrospectively analyzed 250 children after proctocolectomy with either SIAA or JPAA, for the first 3 years after pull-through. A functional stooling score was developed to further assess outcomes. Data were analyzed using chi(2) tests and generalized linear mixed models for repeated measures.

RESULTS

Two hundred three patients had sufficient data for complete analysis (42% males; mean surgery age, 15 +/- 7years). Surgical indications were ulcerative colitis (168) and familial adenomatoid polyposis (35). Surgical procedures included SIAA (112) and JPAA (91). Daytime and nighttime stooling frequencies were significantly higher (P < .013) for SIAA patients at 1 to 24 months after pull-through; however, stooling frequencies began approximating each other by this time. Symptomatic pouchitis (compared to enteritis after SIAA) was significantly higher in JPAA patients (odds ratio, 4.5; confidence interval, 2.32-8.72). Frequency of pouchitis declined with time. There was no significant difference in the incidence of surgical complications between the 2 groups. Finally, continence rates were strikingly good in both groups compared to previously reported series.

CONCLUSION

Straight ileoanal anastomosis and JPAA are associated with considerable morbidity; SIAA has higher stool frequency and JPAA has increased pouchitis. Over time, we found that problems improved, and functional stooling scores became similar. JPAA had consistently lower stool frequency and better continence rates; however, these differences were small and may have minimal clinical significance. In addition, such differences need to be balanced against the high rate of pouchitis with JPAA. Continence was excellent regardless of the technique.

Leptin accelerates enterocyte turnover during methotrexate-induced intestinal mucositis in a rat

Gastrointestinal mucositis occurs as a consequence of cytotoxic treatment. In the present study, we tested whether leptin can protect gut epithelial cells from methotrexate (MTX)-induced intestinal damage. Non-pretreated and pretreated with MTX Caco-2 cells were incubated with increasing concentrations of leptin for 24 h. Cell proliferation and apoptosis were assessed using FACS analysis. Adult rats were divided into three experimental groups: Control rats; MTX-rats were treated with a single dose of MTX, and MTX-LEP rats were also treated with leptin for 3 d. Intestinal mucosal damage (Park score), mucosal structural changes (bowel and mucosal weight, mucosal DNA and protein content, villus height and crypt depth), enterocyte proliferation, and enterocyte apoptosis were measured at sacrifice. RT-PCR was used to determine the level of bax and bcl-2 mRNA expression. In the vitro experiment, treatment with leptin of Caco-2 cells pre-treated with MTX resulted in a significant stimulation of cell proliferation and inhibition of cell apoptosis in a dose-dependent manner. In the vivo experiment, MTX-LEP rats demonstrated a greater jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, as well as a greater enterocyte proliferation index compared to MTX-animals. MTX-LEP rats also showed a trend toward an increase in enterocyte apoptosis that was accompanied by an increase in bax mRNA and decrease in bcl-2 mRNA expression. In conclusion, leptin enhances proliferation and decreases apoptosis in Caco-2 cells pretreated with MTX. In a rat model of MTX-induced mucositis, treatment with leptin improves intestinal recovery and enhances enterocyte turnover.

Dietary palmitic acid modulates intestinal re-growth after massive small bowel resection in a rat

PURPOSE

Among factors promoting intestinal adaptation after bowel resection, dietary fatty acids have a special role. The purpose of the present study was to evaluate the effects of palmitic acid (PA) on early intestinal adaptation in rats with short bowel syndrome (SBS).

MATERIALS

Male Sprague-Dawley rats underwent either a bowel transection with re-anastomosis (sham rats) or 75% small bowel resection (SBS rats). Animals were randomly assigned to one of four groups: sham rats fed normal chow (sham-NC); SBS rats fed NC (SBS-NC), SBS rats fed high palmitic acid diet (SBS-HPA), and SBS rats fed low palmitic acid diet (SBS-LPA). Rats were sacrificed on day 14. Parameters of intestinal adaptation, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, cell proliferation and apoptosis were determined at sacrifice. RT-PCR and Western blotting were used to determine the level of bax and bcl-2 mRNA and protein (parameters of apoptosis), and ERK protein levels (parameter of proliferation). Statistical analysis was performed using Kruskal-Wallis test followed by post hoc test for multiple comparisons with P values of less than 0.05 considered statistically significant.

RESULTS

SBS-HFD rats demonstrated higher bowel and mucosal weight, mucosal DNA and protein in ileum, while deprivation of PA (SBS-LPA) inhibited intestinal re-growth both in jejunum and ileum compared to SBS-NC rats. A significant up-regulation of ERK protein coincided with increased cell proliferation in SBS-HFD rats (vs. SBS-NC). Also, the initial decreased levels of apoptosis corresponded with the early decrease in bax and increase in bcl-2 at both mRNA and protein levels.

CONCLUSION

Early exposure to HPA both augments and accelerates structural bowel adaptation in a rat model of SBS. Increased cell proliferation and decreased cell apoptosis may be responsible for this effect. Deprivation of PA in the diet inhibits intestinal re-growth.

Effect of elevated intra-abdominal pressure and hyperoxia on portal vein blood flow, hepatocyte proliferation and apoptosis in a rat model

BACKGROUND/PURPOSE

Indications for a laparoscopic approach for the management of biliary atresia in children are not clearly defined. We have recently shown that persistent intra-abdominal pressure (IAP) significantly decreased portal vein (PV) flow. Ventilation with a high concentration of oxygen after abdomen deflation raises concerns of increased oxidative stress but has also been shown to exert beneficial effects on splanchnic ischemia/reperfusion. The purpose of the present study was to evaluate the effects of IAP and hyperoxia on liver histology, hepatocyte proliferation and apoptosis in a rat model of abdominal compartment syndrome (ACS).

METHODS

Male Sprague-Dawley rats were anesthetized with intraperitoneal ketamine and xylasine. After a midline laparotomy, the PV was isolated. Ultrasonic blood flow probes were placed on the vessel for continuous measurement of regional blood flow. Mean arterial blood pressure (MABP) was continuously measured. Two large-caliber percutaneous peripheral intravenous catheters were introduced into the peritoneal cavity for inflation of air and measurement of IAP. Rats were divided into three experimental groups: 1) Sham rats were subjected to IAP of 0 mmHg; 2) ACS rats were subjected to IAP of 6 mmHg for 2 hours and were ventilated with air; and 3) ACS-O (2) rats were subjected to IAP of 6 mmHg for 2 hours and were ventilated with 100 % O (2) during the operation and ventilation was continued for 6 hours after operation. Liver structural changes, hepatocyte proliferation (using BrdU assay) and apoptosis (using Tunel assay) were determined 24 hours following operation.

RESULTS

IAP at 6 mmHg caused a twofold decrease in PV flow compared to sham animals. Hyperoxia resulted in a less significant decrease in PV flow compared to air-ventilated animals. Despite a significant decrease in PV blood flow, 24 hours after abdominal deflation only a few animals demonstrated histological signs of liver damage. The small histological changes were accompanied by increased hepatocyte apoptosis and enhanced hepatocyte proliferation in 25 % of animals, suggesting a liver repair response.

CONCLUSIONS

Despite a significant decrease in PV blood flow, persistent IAP for 2 hours results in few changes in liver histology, and stimulates hepatocyte proliferation and apoptosis in only a few animals, supporting the presence of a recovering mechanism. Treatment with hyperoxia did not significantly change hepatocyte proliferation and apoptosis.