Epidermal growth factor and bombesin act synergistically to support intestinal adaptation in rats with massive small bowel resection

Intestinal adaptation is the most important event in short bowel syndrome following a massive small bowel resection. Effects of various growth factors and their synergism have been well documented in intestinal adaptation. This study aimed to compare the effect of two different trophic agents, epidermal growth factor (EGF) and bombesin (BBS), on intestinal adaptation following massive intestinal resection. Sprague–Dawley male rats were assigned to one of four groups after a 75% small bowel resection. Either EGF (90 g/kg), BBS (10 g/kg), EGF+BBS, or bovine serum albumin (BSA) were injected subcutaneously three times a day. The animals were killed 10 days after the operation. Weight loss and morphologic parameters such as mucosal thickness, villus height, crypt depth, villus-to-crypt ratio, and muscularis propria height were measured. In the EGF+BBS group, mucosal thickness was found to be significantly increased compared with the other study groups (p<0.05). Similarly, villus height was significantly increased only in the EGF+BBS group (p<0.05). In the BBS group, both villus height and mucosal thickness showed a slight increase, but the values were not statistically significant compared with the vehicle-treated group. There were no significant differences in any of the remaining parameters between the groups. The results of this study indicate that the gut hormones EGF and BBS act synergistically in facilitating the adaptive response of the remnant ileum to massive intestinal resection.     

Effect of leptin on intestinal re-growth following massive small bowel resection in rat

Recent evidence suggests that the adipose tissue-derived cytokine leptin (LEP) is involved in modulation of growth and differentiation of normal small intestine. The purpose of the present study was to evaluate the effects of parenteral LEP on structural intestinal adaptation, cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and re-anastomosis, SBS-rats underwent a 75% small bowel resection, and SBS-LEP-rats underwent bowel resection and were treated with LEP given subcutaneously at a dose of 20 μg/kg, once daily, from day 3 through 14. Parameters of intestinal adaptation (bowel and mucosal weights, mucosal DNA and protein, villus height and crypt depth in jejunum and ileum), enterocyte proliferation and enterocyte apoptosis were determined on day 15 following operation. Ileal tissue samples were taken for detection of bax and bcl-2 gene expression using RT-PCR technique. Statistical analysis was performed using the non-parametric Kruskal–Wallis ANOVA test, with P<0.05 considered statistically significant. Treatment with subcutaneous LEP resulted in a significant increase in jejunal (17%, P<0.05) and ileal (13%, P<0.05) bowel weight, jejunal (10%, P<0.05) and ileal (25%, P<0.05) mucosal weight, jejunal (26%, P<0.05) and ileal (38%, P<0.05) mucosal DNA, ileal (25%, P<0.05) mucosal protein, jejunal (41%, P<0.05) and ileal (21%, P<0.05) villus height, jejunal (37%, P<0.05) crypt depth, and jejunal (24%, P<0.05) and ileal (21%, P<0.05) enterocyte proliferation compared to SBS-animals. Enterocyte apoptosis increased significantly after bowel resection in jejunum and ileum compared to sham animals and was accompanied by an increased bax gene expression and a decreased bcl-2 gene expression in ileal samples. SBS-LEP rats showed a trend toward a decrease in enterocyte apoptosis in ileum and a mild decrease in bax gene expression compared to SBS-untreated animals. In conclusion, in a rat model of SBS parenteral LEP stimulates structural intestinal adaptation. Increased cell proliferation and decreased cell death via apoptosis may be responsible for this increased cell mass.     

Parenteral arginine impairs intestinal adaptation following massive small bowel resection in a rat model

The nitric oxide precursor L-arginine (ARG) has been shown to influence intestinal structure and absorptive function. It is also well known that the route of administration modulates the effects of ARG. The present study evaluated the effects of parenteral ARG on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and reanastomosis, SBS rats underwent a 75% small bowel resection, and SBS-ARG rats underwent a 75% small bowel resection and were treated with ARG given subcutaneously at a dose of 300 g/kg, once daily, from days 3 to 14. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15 following operation. The SBS rats demonstrated a significant increase in jejunal and ileal bowel and mucosal weight, villus height and crypt depth, and cell proliferation index compared with the sham group. The SBS-ARG animals demonstrated lower ileal bowel and mucosal weights, jejunal mucosal DNA and ileal mucosal protein, and jejunal and ileal villus height and crypt depth compared with SBS animals. The SBS-ARG rats also had a lower cell proliferation index in both jejunum and ileum and a greater enterocyte apoptotic index in ileum compared with the SBS-untreated group. In conclusion, in a rat model of SBS, parenteral arginine inhibits structural intestinal adaptation. Decreased cell proliferation and increased apoptosis are the main mechanisms responsible for decreased cell mass.     

Growth-factor enhancement of compromised gut function following massive small-bowel resection

 Our laboratory has shown that epidermal growth factor (EGF) and hepatocyte growth factor (HGF) can improve the function of normal rat small intestine. This study was designed to evaluate the role of these growth factors on the residual small intestine following massive (80%) small bowel resection. Our data demonstrate that EGF and HGF can enhance intestinal substrate absorption and mucosal mass beyond that which occurs with intestinal adaptation. These growth factors may be beneficial in the management of children with short bowel syndrome. Accepted: 13 December 1999     

Current status of small bowel transplantation in children

Small bowel transplantation is gradually changing from an experimental procedure to a very desirable and viable treatment option in children with irreversible intestinal failure due to either short bowel syndrome or functional impairment. Long term total parenteral nutrition and home parenteral nutrition would be necessary to manage these children in the absence of a small bowel transplant programme. Parenteral nutrition is also associated with complications which can result in chronic liver disease. In India, there is no infrastructure for this treatment option and even if it was there the cost of this method of treatment is likely to be more than the cost of post-operative immunosuppression. Small bowel can be transplanted as an isolated graft, in combination with the liver or as part of a multiviscera! transplant. The operative techniques have been standardised. Major post-operative complications result from sepsis and lymphoproliferative diseases. The best results have been obtained with a combined liver and small bowel transplant.     

Intestinal loop lengthening: early treatment of vanishing bowel

Bianchi’s procedure experience for short bowel syndrome in children is positive. This technique is generally performed after the first year of life. Here the authors propose a case of gastroschisis with prenatal spontaneous closure of abdominal defect and vanishing gut presenting as intestinal atresia, absence of ileo-cecal valve, and residual short intestinal dilatation, treated by early gut lengthening (ILP).     

Pharmacologic enhancement of adaptive growth after extensive small-bowel resection

Adaptive hyperplasia, especially of the ileum, is a well-known and extensively studied physiological response that is responsible for the ability of animals to survive extensive small-bowel resection. Luminal nutrients, endogeneous secretions, and humoral factors are considered to be important mediators of this compensatory increase in absorptive surface area. Recently, prostaglandins have been shown to exert a trophic influence on the intestine. The object of this study was to determine whether it is possible to enhance the resection-induced intestinal hyperplasia with a new prostaglandin E₂ (PGE₂) analog (Ro 22–1327). In four groups of rats 4–5 weeks of age, a 70%–80% midintestinal resection was performed. One group (A1) was treated with Ro 22–1327 for 14 days by daily oral gavage; another was treated for 4 weeks (B1). The remaining two groups were used as controls and treated with placebo for 14 days (A2) and 4 weeks (B2). A fifth group was subjected to sham laparotomy without intestinal resection and treatment. In both groups treated for 14 days, relaparotomy was performed on the 14th day and intestinal length and width were measured. Threafter, treatment was discontinued for another 14 days. After 4 weeks the intestinal segments from all animals were removed (jejunal and ileal remnants, cecum, and colon). Lenght, width, and wet and dry weights were measured and surface areas were calculated. The results demonstrate a significant increase in all intestinal parameters in groups treated with the PGE₂ analog. In the small intestine, the trophic response was expressed more in the jejunum. Postresectional adaptive growth in the cecum and colon was also enhanced by Ro 22–1327. The results of this study suggest that trophic substances could be used therapeutically to increase intestinal surface area in patients with short bowel syndrome. Offprint requests to: M. E. HöllwarthSupported by funds from the National Heart Lung and Blood Institute (HL 26441) and Hoffmann-La Roche Inc.     

Surgical treatment of the short bowel syndrome

Long-term survival after massive intestinal resection is now possible with parenteral nutritional support. The expense, morbidity, and inconvenience of this therapy, however, has led to continued interest in alternatives for the treatment of the short bowel syndrome. The goals of surgical therapy in the short bowel syndrome are to increase the area of absorption, slow intestinal transit, and reduce gastric hyperacidity. Selected patients with dilated bowel segments benefit from intestinal tapering or lengthening. Growing neomucosa to increase surface area is not yet clinically efficacious. The results of transplantation remain unsatisfactory despite recent advances in immunosuppression. Antiperistaltic segments, colon interposition, and intestinal valves may benefit patients with sufficient absorptive area but rapid intestinal transit. Recirculating loops are associated with prohibitive morbidity and mortality. Intestinal pacing is currently being investigated. Surgical treatment of the short bowel syndrome is not sufficiently safe and effective to recommend its routine use. Operations should be performed only on selected patients to achieve specific goals. Adjunct procedures should not be carried out at the initial intestinal resection. Most important is continued emphasis on the prevention of intestinal resection and conservation of the intestine when massive resection is necessary.     

Nutritional aspects of the short bowel syndrome

Adequate oral nutrition in patients with short bowel syndrome after operation is limited by the amount of intestine left after resection. The remnant small intestine has an important capacity to compensate for the loss of mucosal tissue and develops intestinal hyperplasia when stimulated by a variety of luminal and extraluminal factors such as nutrients, pancreatic biliary secretions, growth factors and hormones. In order to provide appropriate stimuli for the intestinal adaptation after resection, oral feeding is necessary as early as possible after operation. Among nutrients fat, especially LCT and free fatty acids, are the most stimulating nutrients besides proteins and carbohydrates. They increase pancreatic biliary secretions and the excretion of growth promoting hormones such as enteroglucagon. Because of gastric acid hypersecretion the administration of H2 receptor blocking agents (cimetidine) is recommended in these patients. As oral caloric intake is not sufficient in most patients with short bowel syndrome after operation total parenteral nutrition (TPN) or home-TPN has to be installed for longer periods to supplement the appropriate nutritional needs. Both early oral feeding together with TPN or home-TPN have increased considerably the survival rate of children with short bowel syndrome.     

肠外营养在新生儿短肠综合征治疗中的作用

目的　探讨肠外营养对新生儿短肠综合征 (SBS)患儿治疗的作用。方法　回顾总结1988～ 2 0 0 1年在我院PN支持治疗的 9例新生儿短肠综合征 ,观察PN开始时对患儿生长的影响及PN相关并发症。结果　 9例长期随访中 8例存活 ,1例放弃治疗后死亡。4例出现并发症 ,严重低钙1例 ,血尿、右肾结石 1例 ,胆汁淤积 1例 ,贫血 1例 ,经治疗后痊愈。PN开始迟的 2例 ,第 1个月体重下降明显。PN开始早的 7例 ,3例伴CMV感染者生后 3个月内体重增加较非感染组缓慢 ,两组比较有显著性差异 (t=5 .78,P =0 .0 0 2 )。结论　SBS患儿应早期营养支持。SBS患儿伴CMV感染将严重影响体重增加。SBS患儿PN治疗期间并发症出现率较高 ,应予高度重视。     

Effect of subcutaneous insulin on intestinal adaptation in a rat model of short bowel syndrome

Insulin has been shown to influence intestinal structure and absorptive function. The purpose of the present study was to evaluate the effects of parenteral insulin on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: sham rats underwent bowel transection and reanastomosis, SBS rats underwent a 75% small bowel resection, and SBS-INS rats underwent a 75% small bowel resection and were treated with insulin given subcutaneously at a dose of 1 U/kg, twice daily, from day 3 through day 14. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15 following operation. SBS rats demonstrated a significant increase in jejunal and ileal bowel and mucosal weight, villus height and crypt depth, and cell proliferation index compared with the sham group. SBS-INS animals demonstrated higher jejunal and ileal bowel and mucosal weights, jejunal and ileal mucosal DNA and protein, and jejunal and ileal crypt depth compared with SBS animals. SBS-INS rats also had a greater cell proliferation index in both jejunum and ileum and a trend toward a decrease in enterocyte apoptotic index in jejunum and ileum compared with the SBS untreated group. In conclusion, parenteral insulin stimulates structural intestinal adaptation in a rat model of SBS. Increased cell proliferation is the main mechanism responsible for increased cell mass.     

The role of angiotensin II type 1a receptor on intestinal epithelial cells following small bowel resection in a mouse model

Aim  We have previously shown that inhibition of angiotensin converting enzyme (ACE) significantly reduced intestinal epithelial cell (EC) apoptosis and improved morphometric intestinal adaptation in a mouse model of massive small-bowel resection (SBR). This study attempted to further examine the downstream signaling factors in this system by blocking the action of angiotensin II (ATII), hypothesizing that this would lead to similar improvement of intestinal adaptation after SBR. Method  Two groups of mice (C57BL/6J) underwent either a 60% mid-intestinal resection (SBR group) or a transection/re-anastomosis (Sham group). Because real-time PCR studies showed that only ATII receptor type 1a (ATII-1a) expression was significantly increased after SBR, compared to SHAM mice, we decided to use the specific ATII-1a receptor antagonist Losartan to block this signaling pathway. An additional two groups of mice received daily i.p. injections of Losartan (SBR + Losartan and Sham + Losartan group). At 7 days, the adaptive response was assessed in the remnant gut including villus height, crypt depth, EC apoptosis (TUNEL staining) and proliferation (BrdU incorporation). The apoptotic and proliferation signaling pathways were addressed by analysis of EC mRNA expression. Result  SBR (with and without Losartan) led to a significant increase in villus height and crypt depth. Losartan treatment did not significantly change EC proliferation, but did significantly reduce EC apoptosis rates as compared to the non-treated SBR group. Losartan treatment was associated with a significant reduction of the bax-to-bcl-2 ratio and TNF-α expression after SBR compared to non-treated groups. Interestingly, Losartan-treated groups showed a tremendous increase in proliferation of signaling factors EGFR, KGFR and IL7R, which may indicate an expanded potential for further intestinal adaptation also beyond 7 days after SBR. Conclusion  This study showed that the ATII-1a receptor may be of crucial importance for the modulation of intestinal EC apoptosis, and for regulating the post-resectional EC adaptive response. This paper was presented at the 21st International Symposium Paediatric Surgical Research, 2–4 October, 2008, Leipzig, Germany. Winner of Novartis Awards.     

Radiological aspects of the small bowel after extensive resection in children

The authors present radiological aspects of small bowel after extensive resection. They describe the main phenomena related to compensatory hypertrophy: dilatation of the loops, muscosal fold thickening and motor disturbances. The main complications demonstrated by the radiological examination are presented; gallstones, non-functionning anastomosis, bacterial overgrowth.     

Effect of dietary fat on early morphological intestinal adaptation in a rat with short bowel syndrome

Among factors promoting mucosal hyperplasia after bowel resection, long-chain fatty acids may have a special role. The purpose of the present study was to evaluate the effects of high-fat diet (HFD) on early intestinal adaptation in rats with short bowel syndrome (SBS). 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 three groups: Sham rats fed normal chow (Sham-NC); SBS rats fed NC (SBS-NC); and SBS rats fed HFD (SBS-HFD). Rats were killed on days 3 or 14. Body weight and parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) were determined at time of killing. By day 3, SBS-HFD rats demonstrated higher duodenal and jejunal bowel and mucosal weights and ileal villus height and jejunal crypt depth vs SBS-NC rats. By day 14 SBS-HFD rats continued to demonstrate increased duodenal and jejunal bowel weight and duodenal mucosal weight vs SBS-NC animals. We conclude that early exposure to HFD both augmented and accelerated structural bowel adaptation in a rat model of SBS.     

IGF-IR单克隆抗体对Jurkat细胞增殖及凋亡的影响

目的探讨胰岛素样生长因子Ⅰ受体(IGF-IR)在急性T淋巴细胞白血病(T-ALL)细胞系Jurkat的表达、定位,观察IGF-IR单克隆抗体(MAb)对Jurkat细胞增殖、凋亡的影响。方法 (1)采用免疫细胞化学的方法检测IGF-IR在Jurkat细胞的表达、定位。(2)分别用5个不同实验浓度:0.001μg/mL,0.01μg/mL,0.1μ/mL,1μg/mL,10μg/mL的IGF-IR MAb作用Jurkat细胞48h,用CCK-8试剂盒检测细胞的增殖抑制率。(3)选用10μg/mL的IGF-IR MAb作用Jurkat细胞48h,上流式细胞仪测定细胞的凋亡情况。结果 (1)IGF-IR在Jurkat细胞株100%表达,主要为细胞膜、细胞浆混合表达。(2)0.001μg/mL,0.01μg/mL,0.1μg/mL,1μg/mL,10μg/mL的IGF-IR MAb作用Jurkat细胞株48 h,Jurkat细胞的增殖抑制率分别为:(9.67±1.17)%,(14.89±1.06)%,(17.64±0.81)%,(20.15±1.14)%,(24.10±1.11)%,各组间进行两两比较,差异有显著性(P0.05)。(3)10μg/mL的IGF-IR MAb作用Jurkat细胞48h,实验组的诱导细胞凋亡率分别为:早期凋亡率(13.73±1.16)%,晚期凋亡率(20.44±2.47)%,总凋亡率(34.18±3.41)%;对照组的诱导细胞凋亡率分别为:早期凋亡率(6.27±0.67)%,晚期凋亡率(10.18±0.81)%,总凋亡率(16.45±1.38)%。实验组细胞的早期凋亡率,晚期凋亡率,总凋亡率均较对照组高,差异有显著性(P0.05)。结论 (1)Jurkat细胞普遍表达IGF-IR,主要为细胞膜、细胞浆混合表达。(2)IGF-IR MAb可使Jurkat细胞株的增殖受到抑制,且IGF-IR MAb的浓度越高,抑制率越大。(3)IGF-IR MAb可使Jurkat细胞的凋亡增加。     

Severe ROP in twins after blockage of the renin-angiotensin system during gestation

Blockage of the renin-angiotensin system (RAS) during pregnancy is known to cause serious dysfunction of many organs of the foetus and newborn. Angiotensin II is an angiogenic factor and angiotensin-converting enzyme (ACE) inhibitors prevent retinal neovascularisation and their use in preventing proliferative retinopathy of prematurity has been suggested. We report on twin girls born after 32 gestational weeks, who were exposed to blockage of the RAS during gestation, had severely reduced retinal vasculature and developed severe retinopathy of prematurity (ROP) despite receiving very little extra oxygen. CONCLUSION: It is likely that ACE inhibitors and angiotensin receptor blockers not only reduce pathological neovascularisation but also normal vascularisation of the eyes and other organs.     

上皮生长因子促进肠缺血再灌注损伤后粘膜修复的作用

目的 本实验以１０ｕｇ／ｄ上皮生长因子（ＥＧＦ）皮下给药促进大白鼠小肠缺血再灌注损伤后粘膜的修复,观察细胞的增殖。方法 ＳＤ雄性大白鼠６０只,阻断肠系膜上动脉后去除阻断为小肠缺血再灌注损伤模型,随机分为对照组（Ａ）、皮下放置不含ＥＧＦ缓释片组（Ｂ）和放置ＥＧＦ缓释片组（Ｃ）。观察各组０时（缺血６０分钟再灌注１２０分钟后）、第２、４、８天组织学改变,并进行粘膜细胞ＤＮＡ流式细胞仪分析。结果 组织学检