Umbilical cord mesenchymal stem cell exosomes alleviate necrotizing enterocolitis in neonatal mice by regulating intestinal epithelial cells autophagy

BACKGROUND Necrotizing enterocolitis(NEC)is a severe gastrointestinal disease that affects premature infants.Although mounting evidence supports the therapeutic effect of exosomes on NEC,the underlying mechanisms remain unclear.AIM To investigate the mechanisms underlying the regulation of inflammatory response and intestinal barrier function by umbilical cord mesenchymal stem cell(UCMSCs)exosomes,as well as their potential in alleviating NEC in neonatal mice.METHODS NEC was induced in 5-d-old C57BL/6 pups through hypoxia and gavage feeding of formula containing lipopolysaccharide(LPS),after which the mice received human UCMSC exosomes(hUCMSC-exos).The control mice were allowed to breastfeed with their dams.Ileal tissues were collected from the mice and analyzed by histopathology and immunoblotting.Colon tissues were collected from NEC neonates and analyzed by immunofluorescence.Molecular biology and cell culture approaches were employed to study the related mechanisms in intestinal epithelial cells.RESULTS We found that autophagy is overactivated in intestinal epithelial cells during NEC,resulting in reduced expression of tight junction proteins and an increased inflammatory response.The ability of hUCMSC-exos to ameliorate NEC in a mouse model was dependent on decreased intestinal autophagy.We also showed that hUCMSC-exos alleviate the inflammatory response and increase migration ability in intestinal epithelial cells induced by LPS.CONCLUSION These results contribute to a better understanding of the protective mechanisms of hUCMSC-exos against NEC and provide a new theoretical and experimental foundation for NEC treatment.These findings also enhance our understanding of the role of the autophagy mechanism in NEC,offering potential avenues for identifying new therapeutic targets.

Bone-marrow mesenchymal stem cells reduce rat intestinal ischemia-reperfusion injury, ZO-1 downregulation and tight junction disruption via a TNF-α-regulated mechanism

AIM: To investigate the effect of bone-marrow mesenchymal stem cells (BM MSCs) on the intestinal mucosa barrier in ischemia/reperfusion (I/R) injury. METHODS: BM MSCs were isolated from male Sprague-Dawley rats by density gradient centrifugation, cultured, and analyzed by flow cytometry. I/R injury was induced by occlusion of the superior mesenteric artery for 30 min. Rats were treated with saline, BM MSCs (via intramucosal injection) or tumor necrosis factor (TNF)-α blocking antibodies (via the tail vein). I/R injury was assessed using transmission electron microscopy, hematoxylin and eosin (HE) staining, immunohistochemistry, western blotting and enzyme linked immunosorbent assay.RESULTS: Intestinal permeability increased, tight junctions (TJs) were disrupted, and zona occludens 1 (ZO-1) was downregulated after I/R injury. BM MSCs reduced intestinal mucosal barrier destruction, ZO-1 downregulation, and TJ disruption. The morphological abnormalities after intestinal I/R injury positively correlated with serum TNF-α levels. Administration of anti-TNF-α IgG or anti-TNF-α receptor 1 antibodies attenuated the intestinal ultrastructural changes, ZO-1 downregulation, and TJ disruption. CONCLUSION: Altered serum TNF-α levels play an important role in the ability of BM MSCs to protect against intestinal I/R injury.

Current understanding concerning intestinal stem cells

In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same.

Protective effect of bone marrow mesenchymal stem cells in intestinal barrier permeability after heterotopic intestinal transplantation

AIM: To explore the protective effect of bone marrow mesenchymal stem cells (BM MSCs) in the small intestinal mucosal barrier following heterotopic intestinal transplantation (HIT) in a rat model.

Gut microbiota modulating intestinal stem cell differentiation

Proliferation and differentiation of intestinal stem cell(ISC)to replace damaged gut mucosal epithelial cells in inflammatory states is a critical step in ameliorating gut inflammation.However,when this disordered proliferation continues,it induces the ISC to enter a cancerous state.The gut microbiota on the free surface of the gut mucosal barrier is able to interact with ISC on a sustained basis.Micro-biota metabolites are able to regulate the proliferation of gut stem and progenitor cells through transcription factors,while in steady state,differentiated colono-cytes are able to break down such metabolites,thereby protecting stem cells at the gut crypt.In the future,the gut flora and its metabolites mediating the regulation of ISC differentiation will be a potential treatment for enteropathies.

WJSC 6^(th) Anniversary Special Issues(2):Mesenchymal stem cells Intestinal stem cells and celiac disease

Stem cells(SCs)are the key to tissue genesis and regeneration.Given their central role in homeostasis,dysfunctions of the SC compartment play a pivotal role in the development of cancers,degenerative disorders,chronic inflammatory pathologies and organ failure.The gastrointestinal tract is constantly exposed to harsh mechanical and chemical conditions and most of the epithelial cells are replaced every 3 to 5 d.According to the so-called Unitarian hypothesis,this renewal is driven by a common intestinal stem cell(ISC)residing within the crypt base at the origin of the crypt-to-villus hierarchical migratory pattern.Celiac disease(CD)can be defined as a chronic immune-mediated disease that is triggered and maintained by dietary proteins(gluten)in genetically predisposed individuals.Many advances have been achieved over the last years in understanding of the pathogenic interactions among genetic,immunological and environmental factors in CD,with a particular emphasis on intestinal barrier and gut microbiota.Conversely,little is known about ISC modulation and deregulation in active celiac disease and upon a gluten-free diet.Nonetheless,bone marrow-derived SC transplantation has become an option for celiac patients with complicated or refractory disease.This manuscript summarizes the"state of the art"regarding CD and ISCs,their niche and potential role in the development and treatment of the disease.

Update on small intestinal stem cells

Among somatic stem cells, those residing in the intestine represent a fascinating and poorly explored research field. Particularly, somatic stem cells reside in the small intestine at the level of the crypt base, in a constant balance between self-renewal and differentiation. Aim of the present review is to delve into the mechanisms that regulate the delicate equilibrium through which intestinal stem cells orchestrate intestinal architecture. To this aim, special focus will be addressed to identify the integrating signals from the surrounding niche, supporting a model whereby distinct cell populations facilitate homeostatic vs injury-induced regeneration.

Crypt region localization of intestinal stem cells in adults

The intestinal epithelial lining plays a central role in the digestion and absorption of nutrients,but exists in a harsh luminal environment that necessitates continual renewal.This renewal process involves epithelial cell proliferation in the crypt base and later cell migration from the crypt base to the luminal surface.This process is dependent on multi-potent progenitor cells,or stem cells,located in each crypt.There are about 4 to 6 stem cells per crypt,and these stem cells are believed to generate distinct end-differentiated epithelial cell types,including absorptive cells,goblet cells,enteroendocrine cells and Paneth cells,while also maintaining their own progenitor cell state.Earlier studies suggested that intestinal stem cells were located either in the crypt base interspersed between the Paneth cells [i.e.crypt base columnar(CBC) cell model] or at an average position of 4 cells from the crypt base [i.e.label-retaining cells(LRC +4) model].Recent studies have employed biomarkers in the in vivo mammalian state to more precisely evaluate the location of these progenitor cells in the intestinal crypt.Most notable of these novel markers are Lgr5,a gene that encodes a G-protein-coupled receptor with expression restricted to CBC cells,and Bmi 1,which encodes a chromatin remodeling protein expressed by LRC.These studies raise the possibility that there may be separate stem cell lines or different states of stem cell activation involved in the renewal of normal mammalian intestinal tract.

Adipose-derived mesenchymal stem cells alleviate TNBS-induced colitis in rats by influencing intestinal epithelial cell regeneration, Wnt signaling, and T cell immunity

BACKGROUND Conventional Crohn’s disease(CD)treatments are supportive rather than curative and have serious side effects.Adipose-derived mesenchymal stem cells(ADSCs)have been gradually applied to treat various diseases.The therapeutic effect and underlying mechanism of ADSCs on CD are still not clear.AIM To investigate the effect of ADSC administration on CD and explore the potential mechanisms.METHODS Wistar rats were administered with 2,4,6-trinitrobenzene sulfonic acid(TNBS)to establish a rat model of CD,followed by tail injections of green fluorescent protein(GFP)-modified ADSCs.Flow cytometry,qRT-PCR,and Western blot were used to detect changes in the Wnt signaling pathway,T cell subtypes,and their related cytokines.RESULTS The isolated cells showed the characteristics of ADSCs,including spindle-shaped morphology,high expression of CD29,CD44,and CD90,low expression of CD34 and CD45,and osteogenic/adipogenic ability.ADSC therapy markedly reduced disease activity index and ameliorated colitis severity in the TNBS-induced rat model of CD.Furthermore,serum anti-sacchromyces cerevisiae antibody and panti-neutrophil cytoplasmic antibody levels were significantly reduced in ADSCtreated rats.Mechanistically,the GFP-ADSCs were colocalized with intestinal epithelial cells(IECs)in the CD rat model.GFP-ADSC delivery significantly antagonized TNBS-induced increased canonical Wnt pathway expression,decreased noncanonical Wnt signaling pathway expression,and increased apoptosis rates and protein level of cleaved caspase-3 in rats.In addition,ADSCs attenuated TNBS-induced abnormal inflammatory cytokine production,disturbed T cell subtypes,and their related markers in rats.CONCLUSION Successfully isolated ADSCs show therapeutic effects in CD by regulating IEC proliferation,the Wnt signaling pathway,and T cell immunity.

Intestinal stem cell marker LGR5 expression during gastric carcinogenesis

AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fixed biopsy specimens of intestinal metaplasia(n=90),dysplasia(n=53),gastric adenocarcinoma(n=180),metastases in lymph nodes and the liver(n=15),and lesion-adjacent normal gastric mucosa(controls;n=145)were obtained for analysis from the Peking University Cancer Hospital’s Department of Pathology and Gastrointestinal Surgery tissue archives(January 2003 to December 2011).The biopsied patients’demographic and clinicopathologic data were retrieved from the hospital’s medical records database.Each specimen was subjected to histopathological typing to classify the tumor node metastasis(TNM)stage and to immunohistochemistry staining to detect the expression of the cancer stem cell marker LGR5.The intergroup differences in LGR5 expression were assessed by Spearman’s rank correlation analysis,and the relationship between LGR5 expression level and the patients’clinicopathological characteristics was evaluated by theχ2test or Fisher’s exact test.RESULTS:Significantly more gastric cancer tissues showed LGR5+staining than normal control tissues(all P<0.01),with immunoreactivity detected in 72.2%(65/90)and 50.9%(27/53)of intestinal metaplasia and dysplasia specimens,respectively,52.8%(95/180)of gastric adenocarcinoma specimens,and 73.3%%(11/15)of metastasis specimens,but 26.9%(39/145)of lesion-adjacent normal gastric mucosa specimens.Comparison of the intensity of LGR5+staining showed an increasing trend that generally followed increasing dedifferentiation and tumor spread(normal tissue<dysplasia,<gastric adenocarcinoma<metastasis;all P<0.001),with the exception of expression level detected in intestinal metaplasia which was higher than that in normal gastric tissues(P<0.001).Moreover,gastric cancer-associated enhanced expression of LGR5 was found to be signifcantly associated with age,tumor differentiation,Lauren type and TNM stage(Ⅰ+ⅡvsⅢ+Ⅳ)(all P<0.05),but not with sex,tumor site,location,size,histology,lymphovascular invasion,depth of invasion,lymph node metastasis or distant metastasis.Patients with LGR5+gastric cancer specimens and without signs of metastasis from the original biopsy experienced more frequent rates of recurrence or metastasis during follow-up than patients with LGR5-specimens(P<0.05).CONCLUSION:Enhanced LGR5 is related to progressive dedifferentiation and metastasis of gastric cancer,indicating the potential of this receptor as an early diagnostic and prognostic biomarker.

Induced pluripotent stem cells for therapy personalization in pediatric patients:Focus on drug-induced adverse events

Adverse drug reactions(ADRs)are major clinical problems,particularly in special populations such as pediatric patients.Indeed,ADRs may be caused by a plethora of different drugs leading,in some cases,to hospitalization,disability or even death.In addition,pediatric patients may respond differently to drugs with respect to adults and may be prone to developing different kinds of ADRs,leading,in some cases,to more severe consequences.To improve the comprehension,and thus the prevention,of ADRs,the set-up of sensitive and personalized assays is urgently needed.Important progress is represented by the possibility of setting up groundbreaking patient-specific assays.This goal has been powerfully achieved using induced pluripotent stem cells(iPSCs).Due to their genetic and physiological species-specific differences and their ability to be differentiated ideally into all tissues of the human body,this model may be accurate in predicting drug toxicity,especially when this toxicity is related to individual genetic differences.This review is an up-to-date summary of the employment of iPSCs as a model to study ADRs,with particular attention to drugs used in the pediatric field.We especially focused on the intestinal,hepatic,pancreatic,renal,cardiac,and neuronal levels,also discussing progress in organoids creation.The latter are three-dimensional in vitro culture systems derived from pluripotent or adult stem cells simulating the architecture and functionality of native organs such as the intestine,liver,pancreas,kidney,heart,and brain.Based on the existing knowledge,these models are powerful and promising tools in multiple clinical applications including toxicity screening,disease modeling,personalized and regenerative medicine.

Role of bone marrow-derived mesenchymal stem cells in a rat model of severe acute pancreatitis

AIM:To investigate the role and potential mechanisms of bone marrow mesenchymal stem cells(MSCs) in severe acute peritonitis(SAP).METHODS:Pancreatic acinar cells from Sprague Dawley rats were randomly divided into three groups:nonsodium deoxycholate(SDOC) group(non-SODC group),SDOC group,and a MSCs intervention group(i.e.,a co-culture system of MSCs and pancreatic acinar cells + SDOC).The cell survival rate,the concentration of malonaldehyde(MDA),the density of superoxide dismutase(SOD),serum amylase(AMS) secretion rate and lactate dehydrogenase(LDH) leakage rate were detected at various time points.In a separate study,Sprague Dawley rats were randomly divided into either an SAP group or an SAP + MSCs group.Serum AMS,MDA and SOD,interleukin(IL)-6,IL-10,and tumor necrosis factor(TNF)-α levels,intestinal mucosa injury scores and proliferating cells of small intestinal mucosa were measured at various time points after injecting either MSCs or saline into rats.In both studies,the protective effect of MSCs was evaluated.RESULTS:In vitro,The cell survival rate of pancreatic acinar cells and the density of SOD were significantly reduced,and the concentration of MDA,AMS secretion rate and LDH leakage rate were significantly increased in the SDOC group compared with the MSCs intervention group and the Non-SDOC group at each time point.In vivo,Serum AMS,IL-6,TNF-α and MAD level in the SAP + MSCs group were lower than the SAP group;however serum IL-10 level was higher than the SAP group.Serum SOD level was higher than the SAP group at each time point,whereas a significant betweengroup difference in SOD level was only noted after 24 h.Intestinal mucosa injury scores was significantly reduced and the proliferating cells of small intestinal mucosa became obvious after injecting MSCs.CONCLUSION:MSCs can effectively relieve injury to pancreatic acinar cells and small intestinal epithelium,promote the proliferation of enteric epithelium and repair of the mucosa,attenuate systemic inflammation in rats with SAP.

Effect of poly(3-hydroxyalkanoates) as natural polymers on mesenchymal stem cells

Mesenchymal stem cells(MSCs)are stromal multipotent stem cells that can differentiate into multiple cell types,including fibroblasts,osteoblasts,chondrocytes,adipocytes,and myoblasts,thus allowing them to contribute to the regeneration of various tissues,especially bone tissue.MSCs are now considered one of the most promising cell types in the field of tissue engineering.Traditional petri dish-based culture of MSCs generate heterogeneity,which leads to inconsistent efficacy of MSC applications.Biodegradable and biocompatible polymers,poly(3-hydroxyalkanoates)(PHAs),are actively used for the manufacture of scaffolds that serve as carriers for MSC growth.The growth and differentiation of MSCs grown on PHA scaffolds depend on the physicochemical properties of the polymers,the 3D and surface microstructure of the scaffolds,and the biological activity of PHAs,which was discovered in a series of investigations.The mechanisms of the biological activity of PHAs in relation to MSCs remain insufficiently studied.We suggest that this effect on MSCs could be associated with the natural properties of bacteria-derived PHAs,especially the most widespread representative poly(3-hydroxybutyrate)(PHB).This biopolymer is present in the bacteria of mammalian microbiota,whereas endogenous poly(3-hydroxybutyrate)is found in mammalian tissues.The possible association of PHA effects on MSCs with various biological functions of poly(3-hydroxybutyrate)in bacteria and eukaryotes,including in humans,is discussed in this paper.

Current knowledge on the multiform reconstitution of intestinal stem cell niche

The development of“mini-guts”organoid originates from the identification of Lgr5+intestinal stem cells(ISCs)and circumambient signalings within their specific niche at the crypt bottom.These in vitro self-renewing“mini-guts”,also named enteroids or colonoids,undergo perpetual proliferation and regulated differentiation,which results in a high-performance,self-assembling and physiological organoid platform in diverse areas of intestinal research and therapy.The triumphant reconstitution of ISC niche in vitro also relies on Matrigel,a heterogeneous sarcoma extract.Despite the promising prospect of organoids research,their expanding applications are hampered by the canonical culture pattern,which reveals limitations such as inaccessible lumen,confine scale,batch to batch variation and low reproducibility.The tumor-origin of Matrigel also raises biosafety concerns in clinical treatment.However,the convergence of breakthroughs in cellular biology and bioengineering contribute to multiform reconstitution of the ISC niche.Herein,we review the recent advances in the microfabrication of intestinal organoids on hydrogel systems.

Lgr5^+ intestinal stem cell sorting and organoid culture

Intestinal epithelial stem cells (IESCs) are one of the most rapidly self‐renewing and proliferating adult stem cells. The IESCs reside at the bottom of intestinal and colonic crypts, giving rise to all intestinal epithelial lineages and maintaining intestinal epithelial replenishment. The technique of three‐dimensional culture based upon intestinal stem cell biology has been recently developed to study gastrointestinal development and disease pathogenesis. Here, we summarize the techniques used to isolate Lgr5‐ positive IESCs to form the enteroids from intestine or colonoids from colon, and present the means to examine these organoid functions. This study will provide a simple and practical way for producing intestinal tissues in the laboratory.

Modulation of stem cell fate in intestinal homeostasis,injury and repair

The mammalian intestinal epithelium constitutes the largest barrier against the external environment and makes flexible responses to various types of stimuli.Epithelial cells are fast-renewed to counteract constant damage and disrupted barrier function to maintain their integrity.The homeostatic repair and regeneration of the intestinal epithelium are governed by the Lgr5+intestinal stem cells(ISCs)located at the base of crypts,which fuel rapid renewal and give rise to the different epithelial cell types.Protracted biological and physicochemical stress may challenge epithelial integrity and the function of ISCs.The field of ISCs is thus of interest for complete mucosal healing,given its relevance to diseases of intestinal injury and inflammation such as inflammatory bowel diseases.Here,we review the current understanding of the signals and mechanisms that control homeostasis and regeneration of the intestinal epithelium.We focus on recent insights into the intrinsic and extrinsic elements involved in the process of intestinal homeostasis,injury,and repair,which fine-tune the balance between self-renewal and cell fate specification in ISCs.Deciphering the regulatory machinery that modulates stem cell fate would aid in the development of novel therapeutics that facilitate mucosal healing and restore epithelial barrier function.

Soy polysaccharide maintains colonic homeostasis to protect from dextran sulphate sodium-induced colitis by modulating gut microbiota and intestinal epithelial regeneration

Soy polysaccharide(SP)has been reported to possess the properties of modulating gut microbiome diversity.Here,we aimed to explore the protective effects of SP against dextran sulphate sodium(DSS)-induced colitis.Pre-treatment with SP at a dosage of 400 mg/kg·day alleviated colitis symptoms,preventing the weight loss and colon shorten.SP suppressed DSS-induced inflammatory response and enhanced M1 to M2 macrophage polarization.Further investigation showed that SP significantly promoted the regeneration of crypt and the expansion of goblet cell production.In addition,bacterial 16S rRNA sequencing analysis showed that SP modulated the composition of fecal microbiota,including selectively increasing Lactobacillus relative abundance.Notably,SP treatment enriched the production of Lactobacillus-derived lactic acid,which was sensed by its specific G-protein-coupled receptor 81(Gpr81)/Wnt3/β-catenin signaling,and promoted the regeneration of intestinal stem cells.Fecal microbiome transplantation demonstrated that intestinal flora partially contributed to the beneficial effects of SP on preventing against colitis.In conclusion,SP exhibited the protective effects against colitis,which could be partly associated with modulating the composition of gut microbiota and enrichment of lactic acid.This study suggests that SP has potential to be developed as nutritional intervention to prevent colitis.

Monomorphic epitheliotropic intestinal T-cell lymphoma with bone marrow involved: A case report

BACKGROUND Monomorphic epithelial intestinal T-cell lymphoma(MEITL)is a rare type of peripheral T-cell lymphoma.The clinical manifestations are diarrhea,abdominal pain,perforation and an abdominal mass.CASE SUMMARY We present a 52-year-old female patient who was diagnosed with MEITL.Further disease progression was observed after multiline chemotherapy.Eventually,the patient died of a severe infection.CONCLUSION MEITL is a rare intestinal primary T-cell lymphoma with aggressive behavior,a high risk of severe life-threatening complications,and a poor prognosis.

白细胞介素10工程化修饰人脐带间充质干细胞优效治疗炎症性肠病

背景:间充质干细胞来源广泛、易体外增殖,并可分泌一系列免疫调节因子抑制炎症、促进组织修复再生,广泛应用于各种疾病治疗研究。但是对于多种疾病,间充质干细胞的治疗效果有限。针对疾病特定发病机制或者干预靶点进行工程化修饰间充质干细胞是未来细胞治疗的重要发展方向。目的:白细胞介素10是一种典型的抗炎细胞因子,有助于调节免疫反应并诱导巨噬细胞向抗炎表型极化,该研究探讨白细胞介素10基因工程化修饰人脐带间充质干细胞对炎症性肠病的治疗效果。方法:通过电转染建立稳定过表达人白细胞介素10基因的人脐带间充质干细胞,并基于细胞治疗产品标准筛选出临床级细胞。给予C57BL/6J小鼠自由饮用5%葡聚糖硫酸钠盐水溶液建立急性结肠炎模型,分别在造模前1 d(尾静脉途径)与造模后第4天(腹腔途径)注射空质粒转染的人脐带间充质干细胞或过表达人白细胞介素10基因的人脐带间充质干细胞(1×10~6个/只)。在造模后第6天取结肠组织进行苏木精-伊红染色评估组织学变化,免疫荧光染色检测增殖细胞核抗原与CD31的表达。结果与结论:构建的稳定过表达白细胞介素10的工程化人脐带间充质干细胞,满足临床级人脐带间充质干细胞质量标准;人脐带间充质干细胞对小鼠急性结肠炎具有修复效果,过表达白细胞介素10基因的人脐带间充质干细胞的治疗效果更加优效,更显著地抑制急性结肠炎小鼠的体质量下降(P<0.05)、结肠缩短(P<0.05)以及结肠组织损伤(P<0.05);过表达白细胞介素10基因人脐带间充质干细胞组结肠组织切片中增殖细胞核抗原阳性细胞与CD31阳性细胞显著多于人脐带间充质干细胞组,表明过表达白细胞介素10基因的人脐带间充质干细胞可能通过显著促进肠组织细胞增殖和血管再生进而促进结肠组织修复。

黄芩汤调控肠道菌群治疗小鼠肠道急性移植物抗宿主病的机制

背景:肠道急性移植物抗宿主病是异基因造血干细胞移植后最凶险的并发症之一,具有较高的致死率,如何通过应用中药改善肠道炎症、调节自噬以治疗肠道急性移植物抗宿主病是当下值得研究的问题。目的:探讨黄芩汤调控肠道菌群治疗肠道急性移植物抗宿主病的机制。方法:CB6F1小鼠经总剂量8 Gy的60Co X射线照射后通过尾静脉输入Balb/c H-2d小鼠的单个核细胞悬液(骨髓+脾)制备急性移植物抗宿主病模型,随机分为模型组及黄芩汤高、中、低剂量组。造模后分别给予不同剂量黄芩汤或等体积生理盐水连续灌胃14 d,进行临床急性移植物抗宿主病评分并记录生存时间,取小肠组织做苏木精-伊红染色行小肠黏膜病理分级评分。使用16S rDNA测序检测各组小鼠肠道菌群,行免疫荧光、免疫组化染色、PCR等检测自噬相关标志物的表达。结果与结论:(1)与模型组相比,黄芩汤中、高剂量组小鼠存活时间显著延长(P<0.01),临床急性移植物抗宿主病评分显著降低(P<0.01),小肠黏膜病理分级评分显著降低(P<0.01),小肠组织炎症因子肿瘤坏死因子α、白细胞介素1β、白细胞介素6水平显著下降(P<0.01),小鼠小肠黏膜上皮结构完整性部分恢复;(2)肠道菌群研究发现,与模型组相比,黄芩汤中剂量组促炎菌株肠球菌显著减少(P<0.05),而有益菌如梭状芽孢杆菌及促自噬的红球菌显著增多(P<0.05);(3)与模型组相比,黄芩汤中剂量组的自噬标志物显著升高(P<0.05);透射电镜下,黄芩汤中剂量组自噬泡数量显著增多;(4)结果表明:黄芩汤显著降低条件性致病菌丰度和小肠组织炎症因子水平,并提高有益菌相对丰度,同时促进小肠黏膜自噬的表达,从而明显改善急性移植物抗宿主病小鼠肠道症状。