Inhibiting hydrogen sulfide production in umbilical stem cells reduces their protective effects during experimental necrotizing enterocolitis

IntroductionUmbilical mesenchymal stem cells (USC) have been shown to reduce illness in animal models of necrotizing enterocolitis (NEC), possibly through the paracrine release of hydrogen sulfide (H₂S). We hypothesized that animals treated with USCs with inhibited H₂S synthesis would exhibit more severe disease.MethodsNEC was induced in five-day-old mouse pups by formula feeding and hypoxic and hypothermic stress. Experimental groups received intraperitoneal injection of either saline vehicle or 80,000cells/gram of one of the following cell types: USC, USCs with negative-control siRNA, or USCs with targeted siRNA inhibition of the H₂S-producing enzymes. Pups were monitored by clinical assessment and after euthanasia, intestine and lung histologic injury were scored. Tissue was homogenized, and concentrations of IL-6, IL-10, and VEGF were determined by ELISA. For statistical analysis, p < 0.05 was considered significant.ResultsAnimals treated with negative-control siRNA USCs were significantly improved compared to vehicle. Clinical sickness scores as well as intestinal and lung histologic injury scores in the targeted siRNA groups were significantly worse when compared to the negative-control siRNA group. IL-6, IL-10, and VEGF had varying patterns of expression in the different groups.ConclusionInhibition of H₂S production in USCs reduces the beneficial effects of these cells during therapy in experimental NEC.Level of evidenceAnimal studies are typically described as “foundational evidence” without a true level assigned.Type of studyAnimal Study.     

Progress in elucidating the relationship between Helicobacter pylori infection and intestinal diseases

Helicobacter pylori (H. pylori) infection causes changes to the intestinal flora, such as small intestinal bacterial overgrowth, and increases gastric acid secretion-stimulating gastrointestinal hormones, mainly gastrin, due to a decrease in gastric acid caused by atrophic gastritis. In addition, the cellular components of H. pylori travel through the intestinal tract, so the bacterial infection affects the immune system. Therefore, the effects of H. pylori infection are observed not only in the stomach and the proximal duodenum but also in the small and large intestines. In particular, meta-analyses reported that H. pylori-infected individuals had an increased risk of colorectal adenoma and colorectal cancer. Moreover, a recent study reported that the risk of developing colorectal cancer was increased in subjects carrying H. pylori vacuolating cytotoxin A antibody. In addition, it has been reported that H. pylori infection exacerbates the symptoms of Fabry’s disease and familial Mediterranean fever attack and is involved in irritable bowel syndrome and small intestinal ulcers. On the other hand, some studies have reported that the frequency of ulcerative colitis, Crohn’s disease, and celiac disease is low in H. pylori-infected individuals. Thus, H. pylori infection is considered to have various effects on the small and large intestines. However, few studies have reported on these issues, and the details of their effects have not been well elucidated. Therefore, additional studies are needed.     

Vitrification preserves murine and human donor cells for generation of tissue-engineered intestine

Background

Short bowel syndrome causes significant morbidity and mortality. Tissue-engineered intestine may serve as a viable replacement. Tissue-engineered small intestine (TESI) has previously been generated in the mouse model from donor cells that were harvested and immediately reimplanted; however, this technique may prove impossible in children who are critically ill, hemodynamically unstable, or septic. We hypothesized that organoid units (OU), multicellular clusters containing epithelium and mesenchyme, could be cryopreserved for delayed production of TESI.

Methods

OU were isolated from <3 wk-old mouse or human ileum. OU were then cryopreserved by either standard snap freezing or vitrification. In the snap freezing protocol, OU were suspended in cryoprotectant and transferred directly to −80°C for storage. The vitrification protocol began with a stepwise increase in cryoprotectant concentration followed by liquid supercooling of the OU solution to −13°C and nucleation with a metal rod to induce vitrification. Samples were then cooled to −80°C at a controlled rate of −1°C/min and subsequently plunged into liquid nitrogen for long-term storage. OU from both groups were maintained in cryostorage for at least 72 h and thawed in a 37°C water bath. Cryoprotectant was removed with serial sucrose dilutions and OU were assessed by Trypan blue assay for post-cryopreservation viability. Via techniques previously described by our laboratory, the thawed murine or human OU were either cultured in vitro or implanted on a scaffold into the omentum of a syngeneic or irradiated Nonobese Diabetic/Severe Combined Immunodeficiency, gamma chain deficient adult mouse. The resultant TESI was analyzed by histology and immunofluorescence.

Results

After cryopreservation, the viability of murine OU was significantly higher in the vitrification group (93 ± 2%, mean ± standard error of the mean) compared with standard freezing (56 ± 6%) (P < 0.001, unpaired t-test, n = 25). Human OU demonstrated similar viability after vitrification (89 ± 2%). In vitro culture of thawed OU produced expanding epithelial spheres supported by a layer of mesenchyme. TESI was successfully generated from the preserved OU. Hematoxylin and eosin staining demonstrated a mucosa composed of a simple columnar epithelium whereas immunofluorescence staining confirmed the presence of both progenitor and differentiated epithelial cells. Furthermore, beta-2-microglobulin confirmed that the human TESI epithelium originated from human cells.

Conclusions

We demonstrated improved multicellular viability after vitrification over conventional cryopreservation techniques and the first successful vitrification of murine and human OU with subsequent TESI generation. Clinical application of this method may allow for delayed autologous implantation of TESI for children in extremis.     

甘露醇作为口服对比剂用于小肠MR检查的技术研究

目的探讨甘露醇作为对比剂用于小肠MRI的价值。方法将20名志愿者随机分为两组,每组10人,分别口服目前研究较多的甘露醇混合液和2.5%甘露醇,行MR扫描,从扩张度、图像质量、不良反应几个方面对两组进行对比。结果从小肠平均扩张度和不良反应方面两者无显著统计学意义(P&gt;0.05),从4、5、6段小肠的扩张度和图像质量方面对比,甘露醇混合液较2.5%甘露醇效果好,两者有统计学意义(P&lt;0.05)。结论甘露醇作为对比剂用于小肠MR检查效果较好,甘露醇混合液对小肠的扩张效果和图像质量较2.5%甘露醇好。     

腹部手术后肠蠕动功能变化的实验性研究

目的：观察家兔腹部手术后肠蠕动功能的变化。方法：30例家兔随机分为正常对照组、假手术组、模型组,胃肠减压、禁食、全麻后行肠切除肠端吻合术,观察各组动物血浆中胃肠激素：生长抑素（SS）、P物质（SP）、胃动素（MOT）、血管活性肠肽（VIP）、小肠推进率及小肠肌电（BER）变化情况。结果：假手术组3 h BER低于正常对照组（P〈0.05）,6-48 h BER与正常对照组比较无明显差异（P〉0.05）;模型组BER、小肠推进率及血浆中胃肠激素水平均低于对照组（P〈0.05,P〈0.01）。结论：腹部手术后小肠蠕动功能受到抑制,胃肠激素分泌改变。     

肠和肾血氧饱和度能较好预测小儿先天性心脏病术后急性肾损伤

目的：研究脑、肠、肾区域血氧饱和度（rSO₂）预测小儿先天性心脏病术后急性肾损伤（AKI）发生的价值。方法：选择2020年1—12月在上海交通大学医学院附属上海儿童医学中心进行体外循环先天性心脏病纠治术、体重大于2.5?kg且年龄在1岁及以下的患儿57例。采用近红外光谱连续监测患儿术后48?h内脑、肠、肾rSO₂。比较AKI组与非AKI组,以及发生与未发生2级及以上AKI患儿脑、肠、肾rSO₂的变化差异,并采用ROC曲线分析肠、肾rSO₂对术后发生AKI及严重程度的预测价值。结果：57例患儿中,38例（66.7%）发生AKI,其中AKI 1级18例（47.4%）,AKI 2级9例（23.7%）,AKI 3级11例（28.9%）,AKI总发生率约为66.7%。AKI组与非AKI组脑rSO₂的变化差异无统计学意义（F=0.012,P>0.05）,但AKI组肠rSO₂和肾rSO₂明显低于非AKI组（F=5.017和5.003,均P<0.05）。发生与未发生2级及以上AKI患儿脑rSO₂的变化差异无统计学意义（F=0.311,P>0.05）,但发生2级及以上AKI患儿肠rSO₂和肾rSO₂均低于未发生2级及以上AKI患儿（F=6.431和14.139,均P<0.05）。对术后AKI的预测效能进行分析发现,24?h内肠rSO₂的诊断效能较好,其中术后3?h肠rSO₂诊断AKI的曲线下面积（AUC）为0.823,以术后3?h肠rSO₂低于85%预测AKI的敏感度为66.7%、特异度为89.5%;24~48?h肾rSO₂的诊断效能较好,其中术后31?h肾rSO₂诊断AKI的AUC为0.918,以术后31?h肾rSO₂低于84%预测AKI的敏感度为72.2%、特异度为84.2%。对术后发生2级及以上AKI的预测效能进行分析发现,24?h内肠rSO₂的诊断效能较好,其中术后3?h肠rSO₂诊断2级及以上AKI的AUC为0.829,以术后3?h肠rSO₂低于84%预测2级及以上AKI的敏感度为62.2%、特异度为90.0%;24~48?h肾rSO₂的诊断效能较好,其中术后34?h肾rSO₂诊断2级及以上AKI的AUC为0.826,以术后34?h肾rSO₂低于71%预测2级及以上AKI的敏感度为91.9%、特异度为55.0%。结论：肠、肾rSO₂不仅对术后AKI发生有较好的预测作用,同时对AKI的严重程度也有较好的预测效能。     

Contributions of the intestinal microbiome in lung immunity

The intestine is a critical site of immune cell development that not only controls intestinal immunity but extra‐intestinal immunity as well. Recent findings have highlighted important roles for gut microbiota in shaping lung inflammation. Here, we discuss interactions between the microbiota and immune system including T cells, protective effects of microbiota on lung infections, the role of diet in shaping the composition of gut microbiota and susceptibility to asthma, epidemiologic evidence implicating antibiotic use and microbiota in asthma and clinical trials investigating probiotics as potential treatments for atopy and asthma. The systemic effects of gut microbiota are partially attributed to their generating metabolites including short chain fatty acids, which can suppress lung inflammation through the activation of G protein‐coupled receptors. Thus, studying the interactions between microbiota and immune cells can lead to the identification of therapeutic targets for chronic lower respiratory diseases.     

临床少见的小肠间质瘤误诊原因分析（附二例报告）

目的：提高对小肠间质瘤(small intestinal stromal tumor, SIST)的认识,减少误诊。方法回顾性分析2例 SIST 误诊病例资料,并复习相关文献。结果2013年1月—2014年10月南京鼓楼医院胃肠外科共确诊 SIST 13例,其中误诊2例,误诊率15.38%。例1以右侧腹痛伴发热入院,结合查体及 CT 检查报告诊断阑尾周围脓肿,手术切除脓肿及部分小肠,术后病理诊断为 SIST ⅣB(T4N0cM0)期,基因检测示为 c-kit 野生型。例2以排便困难伴下腹部坠胀入院,CT 及 MRI 检查提示盆腔占位性病变,手术探查发现肿瘤来自小肠中段,坠入盆腔并与周围组织浸润粘连,行小肠肿瘤切除术,术后病理诊断为 SIST ⅢB(T3N0cM0)期,基因检测示 c-kit 第13外显子、PDGFRA 第18外显子突变。术后均未予放化疗及分子靶向药物治疗,随访4~5个月,均未复发转移。结论 SIST 临床表现无特异性,误诊率较高。对于有消化道出血、贫血等症状,影像学提示肠道来源可能的盆腹部占位性病变,或由此引起的急腹症患者,需考虑胃肠道间质瘤可能,及时手术探查并行病理检查是避免误诊的重要措施。     

^99mTc—红细胞核素显象对小肠出血的诊断价值

目的：寻找一种更灵敏，准确的小肠出血诊断方法，弥补其它方法之不足。方法：用99mTc体内标记红细胞核素显象对100例临床疑诊为小肠出血的病人，进行出血定位诊断并与内镜、气钡双重造影及动脉造影比较。结果：显象阳性率为90％，高于其它检查方法，而诸法与手术所见的符合率以显象最高为96％，其它方法均不超过50％．核素显象对小肠出血诊断灵敏性，特异性及准确性分别为96％，98％及95％。结论：核素显象对小肠出血定位诊断是一种很好的检查方法，且安全、可靠、灵敏、准确，对病人无痛苦、无创伤，并可为外科手术提供可靠的信息．