Stem cell therapy applied for digestive anastomosis: Current state and future perspectives

BACKGROUND Digestive tract resections are usually followed by an anastomosis.Anastomotic leakage,normally due to failed healing,is the most feared complication in digestive surgery because it is associated with high morbidity and mortality.Despite technical and technological advances and focused research,its rates have remained almost unchanged the last decades.In the last two decades,stem cells(SCs)have been shown to enhance healing in animal and human studies;hence,SCs have emerged since 2008 as an alternative to improve anastomoses outcomes.AIM To summarise the published knowledge of SC utilisation as a preventative tool for hollow digestive viscera anastomotic or suture leaks.METHODS PubMed,Science Direct,Scopus and Cochrane searches were performed using the key words“anastomosis”,“colorectal/colonic anastomoses”,“anastomotic leak”,“stem cells”,“progenitor cells”,“cellular therapy”and“cell therapy”in order to identify relevant articles published in English and Spanish during the years of 2000 to 2021.Studies employing SCs,performing digestive anastomoses in hollow viscera or digestive perforation sutures and monitoring healing were finally included.Reference lists from the selected articles were reviewed to identify additional pertinent articles.METHODS Given the great variability in the study designs,anastomotic models,interventions(SCs,doses and vehicles)and outcome measures,performing a reliable meta-analysis was considered impossible,so we present the studies,their results and limitations.RESULTS Eighteen preclinical studies and three review papers were identified;no clinical studies have been published and there are no registered clinical trials.Experimental studies,mainly in rat and porcine models and occasionally in very adverse conditions such as ischaemia or colitis,have been demonstrated SCs as safe and have shown some encouraging morphological,functional and even clinical results.Mesenchymal SCs are mostly employed,and delivery routes are mainly local injections and cell sheets followed by biosutures(sutures coated by SCs)or purely topical.As potential weaknesses,animal models need to be improved to make them more comparable and equivalent to clinical practice,and the SC isolation processes need to be standardised.There is notable heterogeneity in the studies,making them difficult to compare.Further investigations are needed to establish the indications,the administration system,potential adjuvants,the final efficacy and to confirm safety and exclude definitively oncological concerns.CONCLUSION The future role of SC therapy to induce healing processes in digestive anastomoses/sutures still needs to be determined and seems to be currently far from clinical use.     

Mechanical Resistance of Different Tree Species to Rockfall in the French Alps

In order to determine the mechanical resistance of several forest tree species to rockfall, an inventory of the type of damage sustained in an active rockfall corridor was carried out in the French Alps. The diameter, spatial position and type of damage incurred were measured in 423 trees. Only 5% of trees had sustained damage above a height of 1.3 m and in damaged trees, 66% of broken or uprooted trees were conifers. Larger trees were more likely to be wounded or dead than smaller trees, although the size of the wounds was relatively smaller in larger trees. The species with the least proportion of damage through stem breakage, uprooting or wounding was European beech (Fagus sylvatica L.). Winching tests were carried out on two conifer species, Norway spruce (Picea abies L.) and Silver fir (Abies alba Mill.), as well as European beech, in order to verify the hypothesis that beech was highly resistant to rockfall and that conifers were more susceptible to uprooting or stem breakage. Nineteen trees were winched downhill and the force necessary to cause failure was measured. The energy (E _fail) required to break or uproot a tree was then calculated. Most Silver fir trees failed in the stem and Norway spruce usually failed through uprooting. European beech was either uprooted or broke in the stem and was twice as resistant to failure as Silver fir, and three times more resistant than Norway spruce. E _fail was strongly related to stem diameter in European beech only, and was significantly higher in this species compared to Norway spruce. Results suggest that European beech would be a better species to plant with regards to protection against rockfall. Nevertheless, all types of different abiotic stresses on any particular alpine site should be considered by the forest manager, as planting only broadleaf species may compromise the protecting capacity of the forest e.g. in the case of snow avalanches.     

An Improved Mechanical Testing Method to Assess Bone-implant Anchorage

Recent advances in material science have led to a substantial increase in the topographical complexity of implant surfaces, both on a micro- and a nano-scale. As such, traditional methods of describing implant surfaces - namely numerical determinants of surface roughness - are inadequate for predicting in vivo performance. Biomechanical testing provides an accurate and comparative platform to analyze the performance of biomaterial surfaces. An improved mechanical testing method to test the anchorage of bone to candidate implant surfaces is presented. The method is applicable to both early and later stages of healing and can be employed for any range of chemically or mechanically modified surfaces - but not smooth surfaces. Custom rectangular implants are placed bilaterally in the distal femora of male Wistar rats and collected with the surrounding bone. Test specimens are prepared and potted using a novel breakaway mold and the disruption test is conducted using a mechanical testing machine. This method allows for alignment of the disruption force exactly perpendicular, or parallel, to the plane of the implant surface, and provides an accurate and reproducible means for isolating an exact peri-implant region for testing.     

吲哚菁绿荧光显像技术在腹腔镜结直肠癌根治术中的临床应用价值分析

摘要 目的：探讨吲哚菁绿荧光显像技术在腹腔镜结直肠癌根治术中的临床应用价值。方法：选取2020 年6月到2021年6月于我院行腹腔镜结直肠癌根治术的患者112例,按照随机数字表法分为研究组和对照组,每组各56例。两组均采用腹腔镜结直肠癌根治术治疗,研究组术中应用吲哚菁绿荧光显像技术观察吻合口肠段血运情况。比较两组患者手术相关指标、术后并发症发生率、吻合口漏、吻合口出血发生率及围手术期死亡率。结果：两组患者术中均无死亡,两组患者术中出血量、手术时间、首次肛门排气时间、下床活动时间及术中死亡率比较无统计学差异（P>0.05）。研究组腹腔出血、腹腔感染、吻合口漏、吻合口出血发生率显著低于对照组（P<0.05）,两组肠梗阻、切口感染、围手术期死亡率比较无统计学差异（P>0.05）。结论：应用吲哚菁绿荧光显像技术可以显著降低腹腔镜结直肠癌根治术患者腹腔出血、腹腔感染、吻合口漏、吻合口出血发生率,在腹腔镜结直肠癌根治术中具有较好的应用价值。     

Production of oncolytic adenovirus and human mesenchymal stem cells in a single‐use,Vertical‐Wheel bioreactor system: Impact of bioreactor design on performance of microcarrier‐based cell culture processes

Anchorage‐dependent cell cultures are used for the production of viruses, viral vectors, and vaccines, as well as for various cell therapies and tissue engineering applications. Most of these applications currently rely on planar technologies for the generation of biological products. However, as new cell therapy product candidates move from clinical trials towards potential commercialization, planar platforms have proven to be inadequate to meet large‐scale manufacturing demand. Therefore, a new scalable platform for culturing anchorage‐dependent cells at high cell volumetric concentrations is urgently needed. One promising solution is to grow cells on microcarriers suspended in single‐use bioreactors. Toward this goal, a novel bioreactor system utilizing an innovative Vertical‐Wheel? technology was evaluated for its potential to support scalable cell culture process development. Two anchorage‐dependent human cell types were used: human lung carcinoma cells (A549 cell line) and human bone marrow‐derived mesenchymal stem cells (hMSC). Key hydrodynamic parameters such as power input, mixing time, Kolmogorov length scale, and shear stress were estimated. The performance of Vertical‐Wheel bioreactors (PBS‐VW) was then evaluated for A549 cell growth and oncolytic adenovirus type 5 production as well as for hMSC expansion. Regarding the first cell model, higher cell growth and number of infectious viruses per cell were achieved when compared with stirred tank (ST) bioreactors. For the hMSC model, although higher percentages of proliferative cells could be reached in the PBS‐VW compared with ST bioreactors, no significant differences in the cell volumetric concentration and expansion factor were observed. Noteworthy, the hMSC population generated in the PBS‐VW showed a significantly lower percentage of apoptotic cells as well as reduced levels of HLA‐DR positive cells. Overall, these results showed that process transfer from ST bioreactor to PBS‐VW, and scale‐up was successfully carried out for two different microcarrier‐based cell cultures. Ultimately, the data herein generated demonstrate the potential of Vertical‐Wheel bioreactors as a new scalable biomanufacturing platform for microcarrier‐based cell cultures of complex biopharmaceuticals. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1600–1612, 2015     

Light-Dependent Chloroplast Reorientation in Mougeotia and Mesotaenium: Riased by Pigment-Regulated Plasmalemma Anchorage Sites to Actin Filaments?

Conjugatophycean green algae, such as Mougeotia and Mesotaenium, are presumably the most ancient organisms to show phytochrome-mediated photomodulatory processes, i.e. chloroplast reorientational movements. Experiments have provided striking evidence for a dichroic mode of light absorption by the phytochrome molecules located at the periphery of the cylindrical cell; in addition, the transition moment of the chromophoric group of phytochrome has been shown to change by a fixed angle upon conversion of P_r to P_fr and vice versa. Consequently, a hypothesis has been put forward involving a tetrapolar phytochrome gradient at the plasmalemma. This presumed pigment pattern precisely controls chloroplast reorientation in the low-irradiance response. Intriguingly, a blue-light absorbing pigment is expressed in Mougeotia as well, which also mediates low-irradiance response via a presumed tetrapolar gradient, apparently independent of the phytochrome. Two hypotheses for the controlling mechanism of chloroplast reorientation have been put forward:

• a) Coupling of the influx of calcium through the plasmalemma to the tetrapolar gradient of the sensor pigment proper, resulting in a tetrapolar gradient of calcium in the cytoplasm. This is the “reorientation via calcium” hypothesis.
• b) Coupling of actin anchorage sites on the plasmalemma to the tetrapolar gradient of the sensor pigment proper, resulting in a tetrapolar gradient of actin anchorage sites. Cytoplasmic calcium, released from internal stores or taken up through the plasmalemma, triggers actomyosin interaction. This is the “reorientation via anchorage sites” hypothesis.

Consistent with the latter hypothesis, photoregulation by two steps seems to be indicated, (i) cytoplasmic initiation of actomyosin interaction, (ii) the graded formation of plasmalemma anchorage sites for actin filaments.     

Functional morphology of the anchorage system and food scrapers of a hillstream fish, Garra lamta (Ham.) (Cyprinidae, Cypriniformes)

The functional morphology of the anchorage system and food scrapers of a hillstream fish, Garra lamta (Ham.) is described in relation to their role in the swift water current of the hillstreams (Ranchi, Bihar, India).     

结直肠漏评分联合中性粒细胞与淋巴细胞比值、C反应蛋白与白蛋白比值对直肠癌Dixon术后吻合口漏的预测价值研究

摘要 目的：研究结直肠漏评分（CLS）联合中性粒细胞与淋巴细胞比值（NLR）、C反应蛋白与白蛋白比值（CAR）对直肠癌低位前切除（Dixon）术后吻合口漏的预测价值。方法：选取2020年4月-2022年3月于贵州医科大学附属医院行直肠癌Dixon手术的260例患者,根据术后吻合口漏发生情况分为吻合口漏组与无吻合口漏组。收集患者临床资料,术后评估两组CLS评分,术后第1、3 d检测中性粒细胞、淋巴细胞计数、C反应蛋白和白蛋白,计算NLR、CAR;采用Logistics回归分析术后吻合口漏的影响因素,采用受试者工作特征（ROC）曲线分析CLS、NLR、CAR对吻合口漏的预测价值。结果：260例患者术后发生20例吻合口漏,发生率为7.69%。吻合口漏组CLS评分高于无吻合口漏组（P＜0.05）;术后第1 d两组NLR、CAR比较差异无统计学意义（P＞0.05）,术后第3 d吻合口漏组NLR、CAR高于无吻合口漏组（P＜0.05）。两组吻合口至肛缘距离、糖尿病史、术前低蛋白血症、术前肠梗阻占比比较差异有统计学意义（P＜0.05）。多因素Logistics回归分析显示,吻合口距肛缘距离、糖尿病史、术前低蛋白血症、术前肠梗阻、CLS、NLR、CAR是患者术后发生吻合口漏的影响因素（P＜0.05）。ROC曲线分析显示,CLS的曲线下面积（AUC）为0.851,NLR的AUC为0.861,CAR的AUC为0.859,三者联合的AUC为0.945,高于单独检测。结论：Dixon术后发生吻合口漏患者CLS评分、NLR和CAR升高,CLS评分联合NLR、CAR可有效预测直肠癌Dixon术后吻合口漏发生风险,可作为评估吻合口漏的辅助指标,以降低术后吻合口漏的发生率。     

外源上皮钙粘着蛋白基因在人肺腺癌细胞中的表达及调节细胞悬浮生长

为了研究上皮钙粘着蛋白（E-cadherin)对人肺腺癌细胞间粘聚和细胞悬浮生长的影响。利用基因重组技术构建了含全长上皮钙粘着蛋白cDNA的真核表达载体。通过脂质体法转染到A549肺腺癌细胞株中,用RT-PCR和Western印迹鉴定并筛选上皮钙粘着蛋白高表达的细胞,株,并观察转染前后肿瘤细胞间粘聚能力的改变以及细胞悬浮培养下的生长状态,结果表明转染细胞间聚集力比对照细胞增强,上皮钙粘着蛋白能够促进细胞悬浮生长的速度。