Role of oxygen radicals in ischemic bowel disorders

Major consequences of ischemic bowel disorders are: enhanced transcapillary filtration, interstitial edema, and sequestration of fluid in the lumen of the bowel. Although several endogenous substances (histamine, prostaglandine, etc.) are released from the small bowel, specific inhibitors do not prevent increased intestinal vascular premeability produced by ischemia reperfusion. Cytotoxic oxygen metabolites — so-called oxygen free radicals — are generated in excess after ischemia during the early reperfusion period and endogenous defense mechanisms are overwhelmed. The highly reactive oxygen radicals damage proteins, lipids, carbohydrates, and nucleotides. Experimental studies showed that pretreatment with oxygen free radical scavengers (super-oxide dismutase, catalase, dimethylsulfoxide) provided significant protection againts ischemic injuries to the small bowel. Further studies gave evidence that the enzyme xanthine oxidase, which reacts with hypoxanthine, constitutes the primary source of oxygen radical production after intestinal ischemia. Xanthine oxidase inhibitors (allopurinol, pterin aldehyde) are powerful substances attenuating the ischemia-induced increase in intestinal vascular permeability. Morphometric studies on biopsies obtained after reperfusion of the intestine indicated likewise that pretreatment with superoxide dismutase, allopurinol, etc. largely prevented the typical intestinal epithelial necrosis induced by ischemia reperfusion. The experimental results are promising for further clinical research. It is conceivable that drugs such as allopurinol or superoxide dismutase may become useful as a treatment of ischemic gastrointestinal diseases, such as necrotizing enterocolitis, volvulus, and others. Offprint requests to: D. N. Granger at the above address     

新生儿肠穿孔101例临床分析

目的分析新生儿肠穿孔的临床特点,为改善新生儿肠穿孔的预后提供理论依据。方法回顾性分析2000年1月至2014年6月入住新生儿重症监护病房的101例新生儿肠穿孔患儿的临床资料。结果新生儿肠穿孔的主要病因是新生儿坏死性小肠结肠炎(NEC,41例,40.6%),其次为特发性肠穿孔(17例,16.8%)、先天性巨结肠(10例,9.9%)。特发性肠穿孔组患儿平均出生体重和平均胎龄明显高于NEC组(P0.05);NEC组致病菌以肠球菌为主,特发性肠穿孔组以革兰阴性菌为主,两组病原菌分布不同(P0.05)。Logistic多元回归分析显示,酸中毒、多部位肠穿孔、穿孔至手术时间较长是新生儿死亡的独立危险因素。结论新生儿肠穿孔病因多样,以NEC为主;NEC所致肠穿孔与特发性肠穿孔具有不同的致病菌,两者可能是相互独立的疾病;早期诊断、尽早手术是挽救新生儿肠穿孔患儿生命的主要措施。     

Neonatal intestinal perforation due to congenital defects in the intestinal muscularis

Congenital defect of the muscular layer of the small intestine is a rare cause of spontaneous bowel perforation in premature infants. During the last 12 years we have observed four similar cases. We describe the most recent one, a premature infant who developed two abdominal events. On her 2nd day of life, spontaneous perforation of the distal ileum due to focal absence of the muscular layer occurred. Several weeks later she developed the typical clinical and histological picture of necrotizing enterocolitis. The clinical and histological characteristics of the two different conditions are compared, and the 24 cases reported in the literature are discussed. We conclude that focal absence of intestinal musculature may be not such a rare entity as is commonly believed.     

Neonatal gut injury and infection rate: impact of surgical debridement on outcome

Infectious burden of gut injury (G-INJ) associated with necrotizing enterocolitis (NEC) or with spontaneous intestinal perforation (SIP) in neonates has not been ascertained. We sought to test the hypotheses that: (1) infants with G-INJ develop higher number of infections including non-concurrent infections than infants without G-INJ in a neonatal intensive care unit (NICU); (2) surgical debridement (DEB) of infants with severe G-INJ is associated with lower infectious morbidity and mortality. All infants admitted to the regional NICU from October 1991 to February 2003 were included in this prospective prevalence investigation of G-INJ and infections. Non-viable (<23 week gestational age) infants, infants with congenital anomalies, and those who developed NEC after SIP were excluded. Standard definitions of National Centers for Disease Control and Prevention were used for different categories of infections. Episodes of infections were classified as concurrent or non-concurrent (post G-INJ) based upon their timing in association with G-INJ. Infants with G-INJ associated with Bell stage II or higher NEC or with SIP were further stratified by DEB into two subgroups. A previously described 7-point clinical score was used to divide G-INJ into mild (0–2), moderate (3–5), and severe (6–7) categories. Surgical outcomes were determined by using χ² and logistic regression analyses. Data are expressed as mean ± SD or as odds ratio (OR) with 95% confidence intervals (CI); P<0.05 was considered significant. Of all 5,481 infants, 954 (17.4%) developed 1,734 episodes of infections. Prevalence of G-INJ was 4% (n=222); of these, 33% (n=73) underwent DEB. Infants with G-INJ had lower mean birth weight (1,414±766 vs. 2,153±104 g; P<0.0001) and lower mean gestational age (29.6±4.2 vs. 32.9±4.8 weeks; P<0.0001) than their peers (n=5,259). Controlling for birth weight and gestational age, odds for non-concurrent blood stream infections (BSIs) in G-INJ infants were higher (OR 13.98, CI 10.289–19.01, P<0.0001) than the remaining population without G-INJ. Forty-four percent of all episodes of fungemia, 32% of all episodes of BSIs occurred in G-INJ infants (P<0.0001). Within the G-INJ group, there were no demographic differences between the DEB and non-DEB infants. Controlling for severity of G-INJ, odds for non-concurrent BSIs (OR 3.45, CI 1.04–11.36, P<0.05) and for mortality (OR 3.35, CI 1–10, P<0.05) among non-DEB infants were higher than in DEB infants. Infants with G-INJ suffered from a disproportionate number of all blood-stream infections in our intensive care nursery. Infants with severe G-INJ whose management includes DEB are more likely to survive and to incur less infectious morbidity.     

维生素D调节坏死性小肠结肠炎新生大鼠肠道上皮occludin蛋白表达的研究

目的：检测坏死性小肠结肠炎(necrotizing enterocolitis,NEC)新生大鼠肠道上皮occludin蛋白的定位及表达情况,探索维生素D处理对NEC新生大鼠的保护作用及对occludin蛋白表达的影响。方法 SPF级不同窝别新生48 h的Wistar大鼠60只,采用随机数字表法随机分为4组：母乳喂养＋对照组10只,母乳喂养＋维生素D组10只,NEC＋对照组20只,NEC＋维生素D组20只。 NEC模型：将生后48 h的仔鼠与母鼠隔离,采用鼠乳代乳品人工喂养＋缺氧＋寒冷刺激处理;维生素D处理：分别于NEC造模前30 min,造模后1 d、2 d腹腔注射活性维生素D(帕立骨化醇)。各组大鼠分别在实验72 h后处死取材,选取回肠组织采用HE染色观察肠腔结构改变并做Nadler病理评分,采用免疫荧光染色观察occludin蛋白在肠上皮的定位和表达情况,采用Western blot方法检测肠道黏膜组织occludin蛋白的表达量并做统计学分析。结果 HE染色可见NEC大鼠的肠腔组织结构破坏,黏膜下或肌层分离,部分绒毛脱落,甚至肠绒毛消失,肠上皮脱落伴肠坏死,Nadler病理评分为(2.90±0.23)分;维生素D处理的NEC大鼠上述病理表现较NEC大鼠减轻,Nadler病理评分为(1.70±0.21)分,两者比较差异有统计学意义(P<0.01)。免疫荧光显示NEC大鼠肠道上皮细胞间occludin表达明显减少、稀疏,呈现不连续或点状表达,维生素D处理的NEC大鼠肠道上皮细胞间occludin表达较NEC对照组大鼠明显增多,基本呈均匀、连续的表达。 Western blot显示NEC大鼠肠道黏膜组织的occludin表达明显减少,维生素D处理可以明显增加 occludin的表达( P <0.01)。结论 NEC 模型大鼠肠道上皮紧密连接相关蛋白occludin表达明显降低,维生素D处理可以通过上调肠道上皮occludin的表达来抑制NEC的发生发展。     

Spontaneous intestinal perforation and Candida peritonitis presenting as extensive necrotizing enterocolitis

Spontaneous intestinal perforation (SIP) has been increasingly reported in very-low-birthweight (VLBW) infants, although it is still less common than necrotizing enterocolitis (NEC). In around one-third of cases, SIP is associated with systemic candidiasis. We describe a case of SIP and Candida peritonitis in a VLBW infant, which was mistakenly diagnosed as NEC during the infant's short life. At laparotomy, the bowel surface was black and thought to be necrotic. As the infant was thought to have whole-bowel necrosis due to NEC, her condition was deemed incompatible with survival. At postmortem, however, the bowel wall was found to be healthy apart from a very localized patch of necrosis associated with a single perforation. The bowel was covered by a thick, black, serosal exudate consisting of fungal elements from Candida albicans. CONCLUSION: This case reinforces the fact that a markedly discoloured bowel is not necessarily necrotic and that the discoloration can potentially recover.     

Spontaneous localized intestinal perforation and intestinal dilatation in very-low-birthweight infants

AIM: To elucidate how spontaneous localized intestinal perforation (SLIP) is related to intestinal morphological features such as dilatation in very-low-birthweight (VLBW) infants. METHODS: The medical records of 13 VLBW infants (<1500 g) undergoing laparotomy between 1983 and 2003 for presumed SLIP were retrospectively reviewed. Clinical findings including maternal, prenatal and perinatal factors were analysed, and the clinical and surgical findings upon laparotomy were compared. RESULTS: Postnatal pathological conditions included patent ductus arteriosus (n=7), sepsis (n=2), respiratory distress syndrome (n=7), intraventricular haemorrhage (n=2), an indwelling catheter via the umbilical vein (n=1) and pneumonia (n=1). Indomethacin was used in seven neonates with patent ductus arteriosus, and dexamethasone preventive therapy was employed in one neonate for bronchopulmonary dysplasia. Operative findings revealed a localized small punched-out perforation in the ileum. Five patients had intestinal dilatation: two with a perforation in the middle of the dilated intestine, and three with a perforation proximal to the region of dilatation. The muscularis propria was absent in the dilated intestine of four patients. CONCLUSION: This study found no significant relationship between perforation and dilatation of the intestine. Perforation may occur in any portion of the ischaemic intestine when circulatory failure becomes severe, and is not necessarily restricted to the dilated intestine. We believe that SLIP and intestinal dilatation may occur on the same basis in low-birthweight infants; however, the disease process may be aetiologically different.     

Perforated enterocyst: a late complication of neonatal necrotizing enterocolitis

Infants with necrotizing enterocolitis (NEC) may develop late sequelae including intestinal stenoses, enteric fistulae, abscess formation, recurrent NEC, cholestasis, malabsorption, short gut syndrome, and enterocyst formation [4]. A case is reported where a child developed an enterocyst arising from the proximal aspect of a defunctionalized Hartmann's pouch 2 years after ileostomy and near-total colectomy. The patient presented with fever and abdominal pain and distension, and was successfully treated by excision of the perforated enterocyst. This rare complication demonstrates that problems may develop in a defunctionalized bowel segment long after primary therapy for NEC.     

A scoring system in predicting the risk of intestinal stricture in necrotizing enterocolitis

Of 46 infants with a diagnosis of necrotizing enterocolitis (NEC) admitted to the neonatal intensive care unit over the period 1981–1985, 40 have been followed from 2 to 6 years after the acute episode. A contrast enema (CE) to look for intestinal strictures (IS) was performed either during the first months in surgically managed patients, or between 2 and 6 years in asymptomatic patients. Clinical, laboratory and radiology parameters collected during the 7 days following NEC were used to establish a score which was correlated with radiological data obtained after CE. Of the 40 infants, 17 developed symptomatic or asymptomatic IS and 16 of these 17 infants has a score 7. Nineteen of the 23 patients without IS had a score <7. We conclude that the proposed score established on day 8 after onset of NEC helps to identify infants at higher risk of developing IS and for whom closer follow up appears necessary.     

Protective effects of vitamin E and omeprazole on the hypoxia/reoxygenation induced intestinal injury in newborn rats

Evaluation of prophylactic effects of omeprazole and/or vitamin E on the formation of free oxygen radicals (FOR) and bowel histopathology in the newborn rat model of hypoxia/reoxygenation (H/R) that resembles human necrotizing enterocolitis (NEC). Eighty newborn rats were randomly divided into eight groups. H/R was done using airtight chamber. Rats were exposed to 100% CO(2) for 15 min followed by a reoxygenation for the next 15 min with 100% O(2). Group 1 (n = 10) was the control group. Group 2 (n = 10) rats received vitamin E. In Group 3 (n = 10) omeprazole was administrated. Group 4 (n = 10) rats received omeprazole and vitamin E. Group 5 (n = 10) rats were subjected to H/R two times for 2 days and one time for 3 days. Group 6 (n = 10) received vitamin E in addition to H/R for 5 days and in Group 7 (n = 10) omeprazole in addition to H/R for 5 days. In Group 8 (n = 10), vitamin E and omeprazole and H/R were applied for 5 days. Rats were killed at the end of the each process and bowel specimens were harvested for histopathological and biochemical investigations. We administrated vitamin E intramuscularly 300 unit/kg per day and omeprazole orally 20 mg/kg per day. Malondialdehyde (MDA), xanthine oxidase (XO), xanthine dehydogenase (XDH) and XO/(XO + XDH) were measured. Vitamin E and/or omeprazole treated rats had significantly less XO% levels than H/R only group (0.36, 0.38 and 0.57, respectively). Similarly, the MDA levels were significantly lower in vitamin E and/or omeprazole received rats than H/R only rats (88.8, 97.9 and 122.6, respectively). All rats treated with omeprazole and/or vitamin E had better biochemical and histopathological levels compared to H/R rats (p < 0.05). Histopathological results show that Group 5 (H/R only) had significantly more intestinal damage when compared with Group 6 (vitamin E + H/R), Group 7 (omeprazole + R/H) and Group 8 (vitamin E + omeprazole + H/R) (p < 0.001). Grade 2 and 3 intestinal damages were only in Group 5 and there were no statistical difference between in Groups 6, 7 and 8 (p > 0.001). Omeprazole and/or vitamin E may protect the biochemical and histopathological intestinal damage of H/R injury in rats. These drugs may be beneficial in the prophylaxis of NEC in humans as well.     

姜黄素对新生大鼠坏死性小肠结肠炎的保护作用

目的：通过研究姜黄素对新生大鼠坏死性小肠结肠炎(NEC)肠组织病理改变,环氧合酶-2(COX-2)表达,肿瘤坏死因子α(TNF-α)及白细胞介素-10 (IL-10)生成的影响,探讨姜黄素对NEC是否有保护作用。方法：40只新生大鼠随机分为4组：正常对照组,溶剂对照组,NEC模型组,姜黄素干预组,每组10只。每日定时观察各组大鼠的一般情况,连续3 d并于第4天处死,取肠道组织检测病理改变,TNF-α、IL-10含量及COX-2的表达。结果：姜黄素能改善NEC模型大鼠一般情况及病理组织学征象;与正常对照组、溶剂对照组比较,NEC模型组,姜黄素干预组TNF-α、IL-10浓度显著增高(P<0.05);姜黄素干预组TNF-α浓度较NEC模型组显著下降(P<0.05)、IL-10浓度较NEC模型组显著升高(P<0.05);姜黄素干预组COX-2表达量显著低于NEC模型组。结论：姜黄素对NEC大鼠具有保护作用,其机制可能与姜黄素抑制COX-2的表达,减少TNF-α的含量、增加 IL-10的含量有关。［中国当代儿科杂志,2010,12（2）：132-136］     

肠道微生物稳态对坏死性小肠结肠炎新生大鼠模型造血系统的影响北大核心CSCD

目的探讨肠道菌群对坏死性小肠结肠炎(necrotizing enterocolitis,NEC)新生大鼠模型造血系统的影响。方法Sprague-Dawley新生大鼠随机分为对照组和模型组(NEC组),每组6只。采用配方奶结合缺氧和冷刺激构建NEC新生大鼠模型。苏木精-伊红染色观察肠组织及造血相关器官病理变化;检测各组血常规;免疫组化法检测造血相关器官中特定细胞的改变;流式细胞术检测骨髓中特定细胞的变化;采用16S rDNA测序技术检测分析各组肠道菌群的组成及丰度。结果与对照组比较,NEC组肠组织充血坏死,肠绒毛破损、萎缩脱落,NEC病理评分显著增加;NEC组外周血白细胞及淋巴细胞计数显著低于对照组(P<0.05);NEC组脾脏、胸腺、骨髓的有核细胞及肝脏的嗜碱性细胞核的小细胞聚集体数量均明显少于对照组;NEC组肝脏中CD71^(+)红系祖细胞显著减少,脾脏、骨髓中的CD45^(+)白细胞及胸腺中的CD3^(+)T淋巴细胞显著降低,骨髓中CD45^(+)CD3^(-)CD43^(+)SSChi的中性粒细胞比例明显下降(P<0.05);NEC组肠道菌群组成与对照组比较差异明显,NEC组利乳杆菌属的相对丰度降低,而埃希菌-志贺菌属的相对丰度显著升高(P<0.05),取代利乳杆菌属成为优势菌属。结论NEC新生大鼠模型存在多谱系造血异常,可能与肠道微生物稳态失衡及致病菌属埃希菌-志贺菌属的异常扩增有关。     

The mechanism of focal intestinal perforations in neonates with low birth weight

Among 36 neonates with intestinal perforations (IP) between 1975 and 1996, 5 had necrotizing enterocolitis (NEC IP) and 10 had focal IPs (FIP). A histologic review of the bowel near the perforations was made to see if there was any difference between cases of NEC IP and FIP. In 1 case of NEC IP, a defect in the musculature was found in addition to disappearance of the mucosal villi and dilated vessels or hemorrhage in the submucosa. Thinning or absence of the intestinal musculature and short villi in the mucosa was observed in 3 cases of FIP, but the acute ischemic changes in FIP were much less than in NEC IP. Hypothesizing that the defective musculature in FIP may be acquired by a vascular accident either before or after birth, we examined the histology of the latest consecutive infants diagnosed as having meconium peritonitis (MP) due to in-utero volvulus and perforation. In the tissue near the perforation, there was an identical focus of thinning and interruption of the musculature while the acute ischemic changes were minimal. We speculate that thinning or absence of the intestinal musculature in FIP may be a result of a transient ischemic event occurring in-utero and that FIP may develop in the damaged intestine after birth when it is fully dilated. Accepted: 1 September 1998     

Effects of omeprazole and gentamicin on the biochemical and histopathological alterations of the hypoxia/ reoxygenation induced intestinal injury in newborn rats

We utilized a newborn rat model of hypoxia/reoxygenation (H/R) that resembles human necrotizing enterocolitis (NEC) to investigate the effects of omeprazole and/or gentamicin on the formation of free oxygen radicals (FOR) and bowel histopathology. For H/R, 1-day-old rats were placed into a chamber of 100% CO₂ for 5 min, then they were reoxygenized for the next 5 min. The rats (n=70) were divided into seven groups: group 1 (control), group 2 (H/R), group 3 (omeprazole), group 4 (H/R+omeprazole), group 5 (gentamicin), group 6 (H/R+gentamicin), group 7 (H/R+omeprazole+gentamicin). Gentamicin and/or omeprazole were given orally for 3 days, then all animals were killed; bowel specimens were harvested. Histopathologic injury scores (HIS) and malonyldialdehyde (MDA) and XO/(XO+XDH) rates (XO; xanthine oxidase, XDH; xanthine dehydrogenase) were measured, which reflect the FOR levels. In group 2, the HIS was significantly higher than groups 4 and 6. The mean MDA values in groups 1–7 were as follows: 54.16, 104.2, 56.85, 63.43, 62.31, 76.85, 79.13, respectively. The mean XO/(XO+XDH) levels were 0.306, 0.461, 0.286, 0.335, 0.323, 0.410, 0.375 from groups 1 –7, respectively. Group 2 rats had significantly more MDA and XO/(XO+XDH) rates versus other groups (P<001). Histopathologic injury and biochemical results were significantly more severe in group 2 than in groups 4 and 6 (P<001). There was no difference between groups 1 and 4 according to XO/(XO+XDH) rates. In newborn rats, H/R produces FOR, which cause serious intestinal damage. Omeprazole and/or gentamicin reduce biochemical and histopathologic bowel damage. This effect was more obvious in omeprazole treated rats. We think omeprazole may open new insights into the treatment of H/R related bowel injuries like NEC.     

肠型脂肪酸结合蛋白检测在足月新生儿坏死性小肠炎中的临床意义

目的 探讨肠型脂肪酸结合蛋白(I-FABP)在足月新生儿坏死性小肠炎(NEC)中的临床应用价值.方法 2012 年2 月至2014 年1 月确诊为NEC 的41 例足月新生儿为病例组,其中Ⅰ期患儿24 例,Ⅱ ~ Ⅲ期患儿17 例;同期确诊为非消化系统疾病的62 例患儿为对照组.采用酶联免疫吸附法(ELISA)检测各组患儿血清I-FABP 和C 反应蛋白(CRP)水平.采用受试者工作特征曲线(ROC)对I-FABP 诊断NEC 进行评估.结果 病例组不同分级患儿血清I-FABP 水平均显著高于对照组(均P<0.05),且Ⅱ ~ Ⅲ期组显著高于Ⅰ期患儿(P<0.05); I-FABP 血清标志物 ROC 曲线下面积(AUC)为0.85(95%CI:0.78~0.92),最佳诊断截点值为2.25 ng/mL,该截点值下诊断NEC 的敏感性为80.49%,特异性为70.19%.病例组与对照组患儿血清CRP 水平差异无统计学意义(P>0.05).结论 血清I-FABP 在NEC 患儿早期(Ⅰ期)已显著升高,并与病情严重程度存在相关性,可作为诊断NEC 的参考指标.     

How can we improve perinatal care in isolated multiple intestinal atresia? A retrospective study with a 30-year literature review

IntroductionMultiple intestinal atresia (MIA) is a rare cause of neonatal intestinal obstruction. To provide an overview of the current prenatal, surgical, and nutritional management of MIA, we report our experience and a literature review of papers published after 1990.MethodsAll cases of isolated MIA (non-hereditary, not associated with apple-peel syndrome or gastroschisis) treated at our institution between 2005 and 2016 were reviewed and compared with cases found in the literature.ResultsSeven patients were prenatally suspected of having intestinal obstruction and were postnatally diagnosed with MIA, with a mean 1.7 (1–2) resections–anastomoses (RA) and 6 (1–10) strictureplasties performed, resulting in a mean resected bowel length of 15.1 cm (15–25 cm). Median time to full oral feed was 46 days (14–626 days). All patients were alive and none had orality disorder after a mean follow-up of 3.1 years (0.2–8.1 years). Three surgical strategies were found in the literature review: multiple RA (68%, 34/50) including Santulli's technique in four of 34 (12%) and anastomoses over a transanastomotic tube (32%, 16/50), with a 98% survival rate, and short-bowel syndrome for only two patients.ConclusionBowel-sparing surgery and appropriate medical management are key to ensuring a favorable nutritional and gastrointestinal outcome and a good prognosis. Prenatal assessment and standardization of the surgical course of treatment remain challenging.