Stem cells as a potential future treatment of pediatric intestinal disorders

Non-intrusive quality appraisal of differentiation-induced cardiovascular stem cells using E-Nose sensor technology

Stem cell technology holds immense potential for revolutionizing medicine, particularly in regenerative treatment for heart disease. The unique capacity of stem cells to differentiate into diverse cell types offers promise in repairing damaged tissues and implanting organs. Ensuring the quality of differentiated cells, essential for specific functions, demands in-depth analysis. However, this process consumes time and incurs substantial costs while invasive methods may alter stem cell features during differentiation and deplete cell numbers. To address these challenges, we propose a non-invasive strategy, using cellular respiration, to assess the quality of differentiation-induced stem cells, notably cardiovascular stem cells. This evaluation employs an electronic nose (E-Nose) and neural pattern separation (NPS). Our goal is to assess differentiation-induced cardiac stem cells (DICs) quality through E-Nose data analysis and compare it with standard commercial human cells (SCHCs). Sensitivity and specificity were evaluated by interacting SCHCs and DICs with the E-Nose, achieving over 90% classification accuracy. Employing selective combinations optimized by NPS, E-Nose successfully classified all six cell types. Consequently, the relative similarity among DICs like cardiomyocytes, endothelial cells with SCHCs was established relied on comparing response data from the E-Nose sensor without resorting to complex evaluations.

Age disparities in intestinal stem cell quantities: a possible explanation for preterm infant susceptibility to necrotizing enterocolitis

PURPOSE

Preterm infants are more susceptible to necrotizing enterocolitis (NEC) than term Queryinfants. This may be due to a relative paucity of Lgr5⁺ or Bmi1⁺-expressing intestinal stem cells (ISCs) which are responsible for promoting intestinal recovery after injury. We hypothesized that the cellular markers of Lgr5⁺ and Bmi1⁺, which represent the two distinct ISC populations, would be lower in younger mice compared to older mice. In addition, we hypothesized that experimental NEC would result in a greater loss of Lgr5⁺ expression compared to Bmi1⁺ expression.

METHODS

Transgenic mice with EGFP-labeled Lgr5 underwent euthanasia at 10 different time points from E15 to P56 (n = 8-11/group). Lgr5⁺-expressing ISCs were quantified by GFP ELISA and Bmi1⁺ was assessed by qPCR. In addition, Lgr5^EGFP mice underwent experimental NEC via formula feeding and hypoxic and hypothermic stress. Additional portions of the intestine underwent immunostaining with anti-GFP or anti-Bmi1⁺ antibodies to confirm ELISA and PCR results. For statistical analysis, p < 0.05 was significant.

RESULTS

Lgr5⁺ and Bmi1⁺expression was lowest in embryonal and early postnatal mice and increased with age in all segments of the intestine. Experimental NEC was associated with loss of Lgr5⁺-expressing ISCs but no significant change in Bmi1⁺ expression.

CONCLUSION

Lgr5⁺ and Bmi1⁺ expression increase with age. Lgr5⁺-expressing ISCs are lower following experimental necrotizing enterocolitis while Bmi1⁺ expression remains relatively unchanged. Developing a targeted medical therapy to protect the low population of ISCs in preterm infants may promote tissue recovery and regeneration after injury from NEC.

HOPX+ injury-resistant intestinal stem cells drive epithelial recovery after severe intestinal ischemia

Intestinal ischemia is a life-threatening emergency with mortality rates of 50%-80% due to epithelial cell death and resultant barrier loss. Loss of the epithelial barrier occurs in conditions including intestinal volvulus and neonatal necrotizing enterocolitis. Survival depends on effective epithelial repair; crypt-based intestinal epithelial stem cells (ISCs) are the source of epithelial renewal in homeostasis and after injury. Two ISC populations have been described: 1) active ISC [aISC; highly proliferative; leucine-rich-repeat-containing G protein-coupled receptor 5 (LGR5⁺)-positive or sex-determining region Y-box 9 -antigen Ki67-positive (SOX9⁺Ki67⁺)] and 2) reserve ISC [rISC; less proliferative; homeodomain-only protein X positive (HOPX⁺)]. The contributions of these ISCs have been evaluated both in vivo and in vitro using a porcine model of mesenteric vascular occlusion to understand mechanisms that modulate ISC recovery responses following ischemic injury. In our previously published work, we observed that rISC conversion to an activated state was associated with decreased HOPX expression during in vitro recovery. In the present study, we wanted to evaluate the direct role of HOPX on cellular proliferation during recovery after injury. Our data demonstrated that during early in vivo recovery, injury-resistant HOPX⁺ cells maintain quiescence. Subsequent early regeneration within the intestinal crypt occurs around 2 days after injury, a period in which HOPX expression decreased. When HOPX was silenced in vitro, cellular proliferation of injured cells was promoted during recovery. This suggests that HOPX may serve a functional role in ISC-mediated regeneration after injury and could be a target to control ISC proliferation.NEW & NOTEWORTHY This paper supports that rISCs are resistant to ischemic injury and likely an important source of cellular renewal following near-complete epithelial loss. Furthermore, we have evidence that HOPX controls ISC activity state and may be a critical signaling pathway during ISC-mediated repair. Finally, we use multiple novel methods to evaluate ISCs in a translationally relevant large animal model of severe intestinal injury and provide evidence for the potential role of rISCs as therapeutic targets.

The application of regenerative medicine in colorectal surgery

Tissue reconstruction and regeneration represent one of the greatest challenges in any surgical field. Regenerative medicine combined with stem cell-based therapy is a novel and promising field of medicine. Stem cells possess the ability to differentiate into specialized cells and to decrease inflammation and therefore can play a role in repair or regeneration of damaged tissues. Colorectal surgery often deals with infected, poorly vascularized, radiated, and inflamed tissue, as well as instances where imperfect healing might have grave implications. This problem has led researchers to study utilizing stem cells in many colorectal conditions, such as anastomotic healing, perianal fistulae, rectovaginal fistulae, anal fissure, and fecal incontinence. The purpose of this review was to discuss prominent studies that explored stem cells utilization in treating different colorectal pathologies.

Protective Effects of Human Milk-Derived Exosomes on Intestinal Stem Cells Damaged by Oxidative Stress

Breastfeeding has been shown to have a protective effect on the occurrence of necrotizing enterocolitis (NEC), but the mechanism remains unclear. In the context of NEC pathogenesis, many of the protective properties of exosomes on the intestinal epithelial compartment make it an ideal therapeutic target. In the present study, our hypothesis was that intestinal stem cells (ISCs) would be protected from injury by human milk-derived exosomes (HMDEs). Human breast milk was collected, and exosomes were isolated using ExoQuick reagent. Magnetic-activated cell sorting isolation of prominin-1⁺ ISCs was performed from small intestines of neonatal rat. ISCs were treated with or without H₂O₂, and HMDEs, an equal volume of HMDE-free milk, or a control solution [phosphate-buffered solution (PBS)] was added, respectively. In the absence of HMDEs, exposure of ISCs to H₂O₂ led to decreased cell viability. However, addition of HMDEs to ISCs exposed to H₂O₂ led to significantly increased ISC viability. There was a significant upregulation of mRNA expression of Axin2, c-Myc, and Cyclin D1 genes of the Wnt/β-catenin axis in ISCs treated with HMDEs (6.99 ± 2.34, 4.21 ± 1.68, 6.17 ± 2.22, respectively, P < 0.05 for all), as compared to control. In the presence of carnosic acid (a specific Wnt/β-catenin signaling inhibitor), the cell viability was significantly decreased. Thus, HMDEs protect ISCs from oxidative stress injury in vitro, which were possibly mediated via the Wnt/β-catenin signaling pathway. Our findings indicate that oral administration of HMDEs might be a promising measure in treating NEC or in preventing the development of NEC in high-risk infants when breast milk is not available.

The emerging role of exosomes in the pathogenesis, prognosis and treatment of necrotizing enterocolitis

Exosomes are a subtype of extracellular vesicles. They contain bioactive molecules, including nucleic acids, proteins and lipids. Among the currently described exosomes, a majority are potential candidates for the diagnosis and treatment of necrotizing enterocolitis (NEC). In this work, we reviewed existing literature reports on exosomes and explored their roles in NEC. Exosomes derived from intestinal epithelial cells (IECs) participates in the development of intestinal diseases, thus can potentially be utilized as biomarkers for NEC. Besides, exosomes of human milk have been demonstrated to protect IECs from oxidative stress, stimulate intestinal stem cells activity, improve the proliferation and migration of IECs, and lower the incidence and severity of experimental NEC. Further, exosomes produced by stem cells can reduce the severity of experimental NEC and protect the intestinal barrier function during NEC. Conclusively, exosomes have been shown to influence the pathogenesis of NEC and exert a protective effect on NEC. However, additional investigations would be urgently necessary to comprehensively elucidate the underlying mechanisms of exosomes in NEC.

Outcome associated with EPCAM founder mutation c.499dup in Qatar

Tufting enteropathy (TE) is a rare autosomal recessive congenital enteropathy that usually requires long-term parenteral nutrition (PN). In the Arabic Peninsula, four distinct EPCAM mutations have been identified to cause TE. As consanguineous marriages are socially favored, pre-marital and pre-conception testing has become a critical disease prevention strategy. This study aimed to identify the pathogenic EPCAM mutations causing TE in Qatari families and determine possible genotype-phenotype correlations. Twenty-two TE patients from seven multiplex families with TE were identified. Blood samples were collected from patients and first-degree relatives. Exons of the gene were amplified and sequenced. Retrospective chart review and/or family interviews were conducted to determine phenotypic characteristics of the disease. Sequence analysis revealed a single, previously described c.499dup mutation in exon 5 of all families tested, suggesting a founder effect. Of the 18 patients whose full clinical information was available, three patients (17%) were off PN with a good quality of life, without intestinal transplantation, and one (6%) was receiving partial PN. Our patients with TE were severely stunted compared to a similar group of patients receiving long-term PN for short bowel syndrome, suggesting that this could possibly be due to TE rather than secondary to inadequate nutrition. Our study identified the EPCAM mutation c.499dup as the genetic defect causing TE in all the participant Qatari families. This finding should facilitate early diagnosis of TE and genetic counseling. Furthermore, it should aid in the prevention of TE through pre-marital screening, antenatal diagnosis, and pre-implantation genetic diagnosis.

Locally Transplanted Adipose Stem Cells Reduce Anastomotic Leaks in Ischemic Colorectal Anastomoses: A Rat Model

BACKGROUND

Anastomotic leakage remains a dreaded complication after colorectal surgery. Stem-cell-based therapies have been shown to increase angiogenesis and cell proliferation.

OBJECTIVE

The purpose of this research was to investigate the use of adipose-derived stem cells on the healing of ischemic colonic anastomoses in a rat model.

DESIGN

This is an animal research study using xenotransplantation.

SETTINGS

Male Wistar rats (300-400 g, n = 48) were purchased from a licensed breeder.

PATIENTS

Adipose stem cells were isolated from the subcutaneous fat of healthy human donors.

INTERVENTIONS

The rats underwent laparotomy with creation of an ischemic colorectal anastomosis created by ligation of mesenteric vessels. The animals were divided into 3 groups: control group with an ischemic anastomosis, vehicle-only group in which the ischemic anastomosis was treated with an absorbable gelatin sponge, and a treatment group in which the ischemic anastomosis was treated with an absorbable gelatin sponge plus adipose stem cells. Animals were killed at postoperative days 3 and 7.

MAIN OUTCOME MEASURES

Anastomotic leakage was defined as the finding of feculent peritonitis or perianastomotic abscess on necropsy. Rat mRNA expression was measured using real-time polymerase chain reaction.

RESULTS

Adipose-derived stem cells significantly decreased anastomotic leakage when compared with control at both postoperative days 3 (25.0% vs 87.5%; p = 0.02) and 7 (25.0% vs 87.5%; p = 0.02). The use of an absorbable gelatin sponge alone had no effect on anastomotic leakage when compared with control and postoperative days 3 or 7. We found that stem cell-treated animals had a 5.9-fold and 7.4-fold increase in the expression of vascular endothelial growth factor when compared with control at 3 and 7 days; however, this difference was not statistically significant when compared with the absorbable gelatin sponge group.

LIMITATIONS

This is a preclinical animal research study using xenotransplantation of cultured stem cells.

CONCLUSIONS

Locally transplanted adipose stem cells enhance the healing of ischemic colorectal anastomoses and may be a novel strategy for reducing the risk of anastomotic leakage in colorectal surgery. See Video Abstract at http://links.lww.com/DCR/B203. EL TRANSPLANTE LOCAL DE CÉLULAS MADRE ADIPOSAS REDUCE LA FUGA ANASTOMÓTICA EN LAS SUTURAS COLORRECTALES ISQUÉMICAS: MODELO EN RATAS: Las fugas anastomóticas son una complicación pusilánime después de toda cirugía colorrectal. Se ha demostrado que el tratamiento con células madre aumenta la angiogénesis y la proliferación celular.Investigar el uso de células madre derivadas de tejido adiposo en la cicatrización de una anastomosis colónica isquémica basada en ratas como modelo.Estudio de investigación en animales utilizando xenotrasplantes.Adquisición de típicas ratas de laboratorio raza Wistar, todas machos (300-400 g, n = 48) de un criadero autorizado.Aislamiento de células madre de tipo adiposo del tejido celular subcutáneo en donantes humanos sanos.Las ratas se sometieron a laparotomía con la creación de una anastomosis colorrectal isquémica obtenida mediante ligadura controlada de los vasos mesentéricos correspondientes. Los animales se dividieron en tres grupos: grupo de control con anastomosis isquémica, grupo de vehículo único en el que la anastomosis isquémica se trató con una esponja de gelatina absorbible, y un grupo de tratamiento en el que la anastomosis isquémica se trató con una esponja de gelatina absorbible asociada a un vástago adiposo de células madre. Los animales fueron sacrificados el POD3 y el POD7.La fuga anastomótica fué definida como el hallazgo de peritonitis fecaloidea o absceso perianastomótico a la necropsia. La expresión de RNAm de las ratas se midió usando PCR en tiempo real.Las células madre derivadas de tejido adiposo disminuyeron significativamente la fuga anastomótica en comparación con el grupo control tanto en el POD3 (25% frente a 87.5%, p = 0.02) como en el POD7 (25% frente a 87.5%, p = 0.02). El uso de una esponja de gelatina absorbible sola, no tuvo efecto sobre la fuga anastomótica en comparación con los controles el POD3 o el POD7. Descubrimos que los animales tratados con células madre adiposas tenían un aumento de 5,9 y 7,4 veces en la expresión de VEGF en comparación con el control a los 3 y 7 días, respectivamente; sin embargo, esta diferencia no fue estadísticamente significativa en comparación con el grupo de esponja de gelatina absorbible.Este es un estudio preclínico de investigación en animales que utiliza xenotrasplantes de células madre adiposas cultivadas.Las células madre de tipo adiposo trasplantadas localmente mejoran la cicatrisación en casos de anastomosis colorrectales isquémicas, y podrían convertirse en una nueva estrategia para reducir el riesgo de fugas anastomóticas en casos de cirugía colorrectal. Consulte Video Resumen en http://links.lww.com/DCR/B203. (Traducción-Dr Xavier Delgadillo).

Preservation of reserve intestinal epithelial stem cells following severe ischemic injury

Intestinal ischemia is an abdominal emergency with a mortality rate >50%, leading to epithelial barrier loss and subsequent sepsis. Epithelial renewal and repair after injury depend on intestinal epithelial stem cells (ISC) that reside within the crypts of Lieberkühn. Two ISC populations critical to epithelial repair have been described: 1) active ISC (aISC; highly proliferative; leucine-rich-repeat-containing G protein-coupled receptor 5 positive, sex determining region Y-box 9 positive) and 2) reserve ISC [rISC; less proliferative; homeodomain only protein X (Hopx)⁺]. Yorkshire crossbred pigs (8-10 wk old) were subjected to 1-4 h of ischemia and 1 h of reperfusion or recovery by reversible mesenteric vascular occlusion. This study was designed to evaluate whether ISC-expressing biomarkers of aISCs or rISCs show differential resistance to ischemic injury and different contributions to the subsequent repair and regenerative responses. Our data demonstrate that, following 3-4 h ischemic injury, aISC undergo apoptosis, whereas rISC are preserved. Furthermore, these rISC are retained ex vivo in spheroids in which cell populations are enriched in the rISC biomarker Hopx. These cells appear to go on to provide a proliferative pool of cells during the recovery period. Taken together, these data indicate that Hopx⁺ cells are resistant to injury and are the likely source of epithelial renewal following prolonged ischemic injury. It is therefore possible that targeting reserve stem cells will lead to new therapies for patients with severe intestinal injury. NEW & NOTEWORTHY The population of reserve less-proliferative intestinal epithelial stem cells appears resistant to injury despite severe epithelial cell loss, including that of the active stem cell population, which results from prolonged mesenteric ischemia. These cells can change to an activated state and are likely indispensable to regenerative processes. Reserve stem cell targeted therapies may improve treatment and outcome of patients with ischemic disease.

Influence of Growth Factors on the Development of Necrotizing Enterocolitis

Growth factors have important roles in gastrointestinal tract development, maintenance, and response to injury. Various experiments have been used to demonstrate growth factor influence in multiple disease processes. These studies demonstrated enhancement of mucosal proliferation, intestinal motility, immune modulation, and many other beneficial effects. Select growth factors, including epidermal growth factor and heparin-binding epidermal growth factor like growth factor, demonstrate some beneficial effects in experimental and clinical intestinal injury demonstrated in necrotizing enterocolitis. The roles of glucagon-like peptide 2, insulin-like growth factor 1, erythropoietin, growth hormone, and hepatocyte growth factor in necrotizing enterocolitis are summarized in this article.

Activation of G protein-coupled estrogen receptor protects intestine from ischemia/reperfusion injury in mice by protecting the crypt cell proliferation

The intestinal ischemia/reperfusion (I/R) injury is a common clinical event related with high mortality in patients undergoing surgery or trauma. Estrogen exerts salutary effect on intestinal I/R injury, but the receptor type is not totally understood. We aimed to identify whether the G protein-coupled estrogen receptor (GPER) could protect the intestine against I/R injury and explored the mechanism. Adult male C57BL/6 mice were subjected to intestinal I/R injury by clamping (45 min) of the superior mesenteric artery followed by 4 h of intestinal reperfusion. Our results revealed that the selective GPER blocker abolished the protective effect of estrogen on intestinal I/R injury. Selective GPER agonist G-1 significantly alleviated I/R-induced intestinal mucosal damage, neutrophil infiltration, up-regulation of TNF-α and cyclooxygenase-2 (Cox-2) expression, and restored impaired intestinal barrier function. G-1 could ameliorate the impaired crypt cell proliferation ability induced by I/R and restore the decrease in villus height and crypt depth. The up-regulation of inducible nitric oxide synthase (iNOS) expression after I/R treatment was attenuated by G-1 administration. Moreover, selective iNOS inhibitor had a similar effect with G-1 on promoting the proliferation of crypt cells in the intestinal I/R model. Both GPER and iNOS were expressed in leucine-rich repeat containing G-protein coupled receptor 5 (Lgr5) positive stem cells in crypt. Together, these findings demonstrate that GPER activation can prompt epithelial cell repair following intestinal injury, which occurred at least in part by inhibiting the iNOS expression in intestinal stem cells (ISCs). GPER may be a novel therapeutic target for intestinal I/R injury.

Stem cell therapy in necrotizing enterocolitis: Current state and future directions

Stem cell therapy is a promising treatment modality for necrotizing enterocolitis. Among the many promising stem cells identified to date, it is likely that mesenchymal stem cells will be the most useful and practical cell-based therapies for this condition. Using acellular components such as exosomes or other paracrine mediators are promising as well. Multiple mechanisms are likely at play in the positive effects provided by these cells, and further research is underway to further elucidate these effects.

Human Adipose Stromal Cells Increase Survival and Mesenteric Perfusion Following Intestinal Ischemia and Reperfusion Injury

OBJECTIVE

Intestinal ischemia can quickly escalate to bowel necrosis and perforation. Transplantation of stem cells presents a novel treatment modality for this problem. We hypothesized that: human adipose-derived stromal cells (hASCs) would increase survival and mesenteric perfusion to a greater degree compared with differentiated cellular controls following ischemic intestinal injury, and improved outcomes with hASC therapy would be associated with preservation of intestinal histological and tight junction architecture, and lower levels of systemic inflammation following intestinal injury.

METHODS

hASCs and keratinocytes (differentiated cellular control) were cultured on polystyrene flasks at 37°C in 5% CO2 in air. Adult male C57Bl6J mice were anesthetized and a midline laparotomy performed. The intestines were eviscerated, the small bowel mesenteric root identified, and intestinal ischemia was established by temporarily occluding the superior mesenteric artery for 60 min with a noncrushing vascular clamp. Following ischemia, the clamp was removed, and the intestines were returned to the abdominal cavity. Before abdominal closure, 2 million hASCs or keratinocytes in 250 μL of phosphate-buffered saline (carrier for cells and control solution) were infused into the peritoneum. Animals were allowed to recover for 12 or 24 h (perfusion, histology, cytokine, and immunofluoresence studies), or 7 days (survival studies). Intestinal perfusion was assessed by laser Doppler imaging. Intestinal tissue segments were stained with hematoxylin and eosin, as well as antibodies for the tight junction protein claudin-1. Separate aliquots of intestine, liver, and lung tissue were homogenized and assessed for inflammatory cytokines via multiplex beaded assay.

RESULTS

Animals administered hASCs following intestinal ischemia and reperfusion (I/R) injury had significantly greater 7-day survival and better postischemic recovery of mesenteric perfusion compared with vehicle or keratinocyte therapy. hASCs also abated intestinal mucosal destruction, facilitated preservation of intestinal tight junctions, and decreased the systemic inflammatory response to injury.

CONCLUSIONS

Human adipose-derived stromal cells improved survival and mesenteric perfusion and attenuated the mucosal damage associated with intestinal I/R injury. hASCs should be considered as a plausible cell source for novel cellular treatment plans following intestinal ischemia.

Umbilical mesenchymal stromal cells provide intestinal protection through nitric oxide dependent pathways

BACKGROUND

Umbilical-derived mesenchymal stromal cells (USCs) have shown promise in the protection of ischemic organs. We hypothesized that USCs would improve mesenteric perfusion, preserve intestinal histological architecture, and limit inflammation by nitric oxide-dependent mechanisms following intestinal ischemia/reperfusion (IR) injury.

METHODS

Adult wild-type C57BL/6J (WT) and endothelial nitric oxide synthase knock out (eNOS KO) mice were used: (1) WT IR + vehicle, (2) WT IR + USC, (3) eNOS KO IR + vehicle, and (4) eNOS KO IR + USC. Mice were anesthetized, and a midline laparotomy was performed. The superior mesenteric artery was clamped with a nonoccluding clamp for 60-min. Following IR, mice were treated with an injection of 250 μL phosphate buffered saline or 2 × 10⁶ USCs suspended in 250-μL phosphate buffered saline solution. Mesenteric perfusion images were acquired using laser Doppler imaging. Perfusion was analyzed as a percentage of baseline. At 24 h, mice were euthanized, and intestines were harvested. Intestines were evaluated for injury, and data were analyzed using the Mann-Whitney or Kruskal-Wallis tests.

RESULTS

Intestinal mesenteric perfusion was significantly improved in WT mice treated with USC therapy compared with eNOS KOs. Intestinal histological architecture was preserved with USC therapy in WT mice. However, in eNOS KO mice, this benefit was abolished. Finally, the presence of several cytokines and growth factors were significantly improved in WT mice compared with eNOS KO mice treated with USCs.

CONCLUSIONS

The benefits of USC-mediated therapy following intestinal IR injury likely occur via nitric oxide-dependent pathways. Further studies are required to define the molecular mechanisms by which USCs activate endothelial nitric oxide synthase to bring about their protective effects.

Stem Cell Therapies in Peripheral Vascular Diseases — Current Status

Peripheral artery diseases include all arterial diseases with the exception of coronary and aortic involvement, more specifically diseases of the extracranial carotids, upper limb arteries, mesenteric and renal vessels, and last but not least, lower limb arteries. Mononuclear stem cells, harvested from various sites (bone marrow, peripheral blood, mesenchymal cells, adipose-derived stem cells) have been studied as a treatment option for alleviating symptoms in peripheral artery disease, as potential stimulators for therapeutic angiogenesis, thus improving vascularization of the ischemic tissue. The aim of this manuscript was to review current medical literature on a novel treatment method — cell therapy, in patients with various peripheral vascular diseases, including carotid, renal, mesenteric artery disease, thromboangiitis obliterans, as well as upper and lower limb artery disease.

Linking stem cell function and growth pattern of intestinal organoids

Intestinal stem cells (ISCs) require well-defined signals from their environment in order to carry out their specific functions. Most of these signals are provided by neighboring cells that form a stem cell niche, whose shape and cellular composition self-organize. Major features of this self-organization can be studied in ISC-derived organoid culture. In this system, manipulation of essential pathways of stem cell maintenance and differentiation results in well-described growth phenotypes. We here provide an individual cell-based model of intestinal organoids that enables a mechanistic explanation of the observed growth phenotypes. In simulation studies of the 3D structure of expanding organoids, we investigate interdependences between Wnt- and Notch-signaling which control the shape of the stem cell niche and, thus, the growth pattern of the organoids. Similar to in vitro experiments, changes of pathway activities alter the cellular composition of the organoids and, thereby, affect their shape. Exogenous Wnt enforces transitions from branched into a cyst-like growth pattern; known to occur spontaneously during long term organoid expansion. Based on our simulation results, we predict that the cyst-like pattern is associated with biomechanical changes of the cells which assign them a growth advantage. The results suggest ongoing stem cell adaptation to in vitro conditions during long term expansion by stabilizing Wnt-activity. Our study exemplifies the potential of individual cell-based modeling in unraveling links between molecular stem cell regulation and 3D growth of tissues. This kind of modeling combines experimental results in the fields of stem cell biology and cell biomechanics constituting a prerequisite for a better understanding of tissue regeneration as well as developmental processes.

Equine Intestinal Mucosal Pathobiology

The equine intestinal mucosa is intimately involved in maintaining homeostasis both on a systemic level by controlling extracellular fluid movement and at the local level to maintain barrier function. Horses are particularly susceptible to the clinical syndrome of colic, with the most severe cases involving strangulating obstruction that induces ischemia. Because of the mucosal vascular architecture, the mucosal epithelium is particularly susceptible to ischemic injury. The potential for reperfusion injury has been investigated and found to play a minimal role. However, inflammation does affect mucosal repair. Mechanisms of repair, including villus contraction, epithelial restitution, and tight junction closure, are critical to reforming the mucosal barrier. Nonsteroidal anti-inflammatory drugs have an impact on this repair, particularly at the level of the tight junctions. Completion of mucosal regeneration requires proliferation, which is now being actively studied in equine enteroids. All of these aspects of equine mucosal pathobiology are reviewed in depth.

Advanced three-dimensional culture of equine intestinal epithelial stem cells

BACKGROUND

Intestinal epithelial stem cells are critical to epithelial repair following gastrointestinal injury. The culture of intestinal stem cells has quickly become a cornerstone of a vast number of new research endeavours that range from determining tissue viability to testing drug efficacy for humans. This study aims to describe the methods of equine stem cell culture and highlights the future benefits of these techniques for the advancement of equine medicine.

OBJECTIVES

To describe the isolation and culture of small intestinal stem cells into three-dimensional (3D) enteroids in horses without clinical gastrointestinal abnormalities.

STUDY DESIGN

Descriptive study.

METHODS

Intestinal samples were collected by sharp dissection immediately after euthanasia. Intestinal crypts containing intestinal stem cells were dissociated from the underlying tissue layers, plated in a 3D matrix and supplemented with growth factors. After several days, resultant 3D enteroids were prepared for immunofluorescent imaging and polymerase chain reaction (PCR) analysis to detect and characterise specific cell types present. Intestinal crypts were cryopreserved immediately following collection and viability assessed.

RESULTS

Intestinal crypts were successfully cultured and matured into 3D enteroids containing a lumen and budding structures. Immunofluorescence and PCR were used to confirm the existence of stem cells and all post mitotic, mature cell types, described to exist in the horse intestinal epithelium. Previously frozen crypts were successfully cultured following a freeze-thaw cycle.

MAIN LIMITATIONS

Tissues were all derived from normal horses. Application of this technique for the study of specific disease was not performed at this time.

CONCLUSIONS

The successful culture of equine intestinal crypts into 3D "mini-guts" allows for in vitro studies of the equine intestine. Additionally, these results have relevance to future development of novel therapies that harness the regenerative potential of equine intestine in horses with gastrointestinal disease (colic).

Mesenchymal stem cells increase antioxidant capacity in intestinal ischemia/reperfusion damage

BACKGROUND

Mesenchymal stem cells (MSCs) may have beneficial effects in reversing intestinal damage resulting from circulatory disorders. The hypothesis of this study is that MSCs increase antioxidant capacity of small bowel tissue following intestinal ischemia reperfusion (I/R) damage.

METHODS

A total of 100 rats were used for the control group and three experimental groups, as follows: the sham control, local MSC, and systemic MSC groups. Each group consisted of 10 animals on days 1, 4, and 7 of the experiment. Ischemia was established by clamping the superior mesenteric artery (SMA) for 45min; following this, reperfusion was carried out for 1, 4, and 7days in all groups. In the local and systemic groups, MSCs were administered intravenously and locally just after the ischemia, and they were investigated after 1, 4, and 7days. The superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (Gpx) activities, as well as malondialdehyde (MDA) and total protein levels, were measured. Histopathological analysis was performed using light and electron microscopy. The indicators of proliferation from the effects of anti- and pro-inflammatory cytokines were evaluated using immunohistochemistry.

RESULTS

MDA was increased (P<0.05) in the sham control group and decreased (P<0.05) in the MSC groups. SOD, CAT, and Gpx were decreased in the local MSC group (P<0.05). The highest level of amelioration was observed on day 7 in the local MSC group via light and electron microscopy. It was found that the MSCs arrived at the damaged intestinal wall in the MSC groups immediately after injection. Pro-inflammatory cytokines interleukin-1β (IL1β), transforming growth factor-β1 (TGFβ1), tumor necrosis factor-α (TNFα), IL6, MIP2, and MPO decreased (P<0.05), while anti-inflammatory cytokines EP3 and IL1ra increased (p<0.05) in the local and systemic MSC groups. In addition, proliferation indicators, such as PCNA and KI67, increased (P<0.05) in the local and systemic MSC groups.

CONCLUSIONS

Parallel to our hypothesis, MSC increases the antioxidant capacity of small bowel tissue after intestinal I/R damage. The MSCs migrated to the reperfused small intestine by homing and reduced oxidative stress via the effects of SOD, CAT, and Gpx, as well as reducing the MDA level; thus, they could increase antioxidant capacity of intestine and have a therapeutic effect on the damaged tissue. We think that this effect was achieved via scavenging of oxygen radicals, suppression of pro-inflammatory cytokines, and increasing the expression of anti-inflammatory cytokines.

Stem cells and necrotizing enterocolitis: A direct comparison of the efficacy of multiple types of stem cells

PURPOSE

Necrotizing enterocolitis (NEC) is a leading cause of gastrointestinal morbidity and mortality in premature infants. While studies have shown potential for stem cell (SC) therapy in experimental NEC, no study has compared different SC side-by-side. Our purpose was to determine whether one type of SC may more effectively treat NEC than others.

METHODS

Four SC were compared: (1) amniotic fluid-derived mesenchymal SC (AF-MSC); (2) amniotic fluid-derived neural SC (AF-NSC); (3) bone marrow-derived mesenchymal SC (BM-MSC); and (4) neonatal enteric neural SC (E-NSC). Using an established rat model of NEC, pups delivered prematurely received an intraperitoneal injection of SC. Control pups were injected with PBS. Additional controls were breast-fed by surrogates and not subjected to experimental NEC. Intestinal tissue was graded histologically.

RESULTS

NEC incidence was: PBS, 61.3%; breast-fed unstressed, 0%; AF-MSC, 19.1%; BM-MSC, 22.9%; AF-NSC, 18.9%; E-NSC 22.2%. All groups demonstrated statistical significance (p<0.05) compared to controls, and there was no difference between SC groups.

CONCLUSION

All four SC groups reduced the incidence and severity of experimental NEC equivalently. AF-MSC may be preferable because of availability of AF at delivery and ease of expansion, increasing potential for clinical translation.

LEVEL OF EVIDENCE

V (Animal study).

Mesenchymal stromal cell therapy for the treatment of intestinal ischemia: Defining the optimal cell isolate for maximum therapeutic benefit

Intestinal ischemia is a devastating intraabdominal emergency that often necessitates surgical intervention. Mortality rates can be high, and patients who survive often have significant long-term morbidity. The implementation of traditional medical therapies to prevent or treat intestinal ischemia have been sparse over the last decade, and therefore, the use of novel therapies are becoming more prevalent. Cellular therapy using mesenchymal stromal cells is one such treatment modality that is attracting noteworthy attention in the scientific community. Several groups have seen benefit with cellular therapy, but the optimal cell line has not been identified. The purpose of this review is to: 1) Review the mechanism of intestinal ischemia and reperfusion injury, 2) Identify the mechanisms of how cellular therapy may be therapeutic for this disease, and 3) Compare various MSC tissue sources to maximize potential therapeutic efficacy in the treatment of intestinal I/R diseases.

Effects of mesenchymal stem cells and VEGF on liver regeneration following major resection

PURPOSE

The study aims to determine the effects of mesenchymal stem cell (MSC) therapy and a combination therapy of MSCs transfected with vascular endothelial growth factor (VEGF) for liver regeneration after major resection.

METHODS

Thirty-eight rats were divided into four groups: group 1: control (sham operation); group 2: control (70 % hepatic resection); group 3: 70 % hepatic resection + systemically transplanted MSCs; and group 4: 70 % hepatic resection + systemically transplanted MSCs transfected with the VEGF gene. MSCs were injected via the portal vein route in study groups 3 and 4. Expression levels of VEGF, fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor (TGF), hepatocyte growth factor (HGF), and augmenter of liver regeneration (ALR) were analyzed in the remnant liver tissue. We investigated the levels of angiogenic factors, VEGF-receptor, angiopoietin-1 (Angpt1) and Angpt2. Biochemical parameters of liver function in blood samples were measured and a histologic assessment of the livers was performed. The postoperative liver weight and volume of each rat were measured 14 days after surgery.

RESULTS

The expression levels of all measured growth factors were significantly increased in groups 3 and 4 compared to the control groups. The levels of Angpt1 and Angpt2 correlated with levels of VEGF and thus were also significantly higher in the study groups. There were significant differences between the estimated liver weights and volumes of group 4 and the resected controls in group 2. With the exception of portal inflammation, levels of all histological parameters were observed to be higher in MSC-treated groups when compared with the resected controls in group 2.

CONCLUSIONS

Transplanted stem cells and MSCs transfected with VEGF significantly accelerated many parameters of the healing process following major hepatic resection. After the injection of MSCs and VEGF-transfected MSCs into the portal vein following liver resection, they were engrafted in the liver. They increased bile duct and liver hepatocyte proliferation, and secreted many growth factors including HGF, TGFβ, VEGF, PDGF, EGF, and FGF via paracrine effects. These effects support liver function, regeneration, and liver volume/weight.

Characterization of discrete equine intestinal epithelial cell lineages

OBJECTIVE

To characterize epithelial cells of the small intestine and colon in horses without clinical gastrointestinal abnormalities with an emphasis on the stem cell niche constituents.

SAMPLE

Mucosal biopsy specimens from small and large intestines obtained from 12 horses euthanized for reasons unrelated to gastrointestinal disease or systemic disease.

PROCEDURES

Intestinal biopsy specimens were collected by sharp dissection immediately following euthanasia. Specimens were prepared for immunohistochemical, immunofluorescence, and transmission electron microscopic imaging to detect and characterize each epithelial cell type. Antibodies against protein biomarkers for cellular identification were selected on the basis of expression in other mammalian species.

RESULTS

Intestinal epithelial cell types were identified by means of immunostaining and morphological characterization with transmission electron microscopy. Some differences in biomarker expression and antibody cross-reactivity were identified in equine tissue, compared with other species. However, each known type of mucosal epithelial cell was identified in equine tissue.

CONCLUSIONS AND CLINICAL RELEVANCE

The methodology used can enhance detection of stem cells and progenitor cells as well as postmitotic cell lineages in equine intestinal tissues. Results may have relevance to regenerative potential of intestinal mucosa and survival in horses with colic.

Animal models of ischemia-reperfusion-induced intestinal injury: progress and promise for translational research

Research in the field of ischemia-reperfusion injury continues to be plagued by the inability to translate research findings to clinically useful therapies. This may in part relate to the complexity of disease processes that result in intestinal ischemia but may also result from inappropriate research model selection. Research animal models have been integral to the study of ischemia-reperfusion-induced intestinal injury. However, the clinical conditions that compromise intestinal blood flow in clinical patients ranges widely from primary intestinal disease to processes secondary to distant organ failure and generalized systemic disease. Thus models that closely resemble human pathology in clinical conditions as disparate as volvulus, shock, and necrotizing enterocolitis are likely to give the greatest opportunity to understand mechanisms of ischemia that may ultimately translate to patient care. Furthermore, conditions that result in varying levels of ischemia may be further complicated by the reperfusion of blood to tissues that, in some cases, further exacerbates injury. This review assesses animal models of ischemia-reperfusion injury as well as the knowledge that has been derived from each to aid selection of appropriate research models. In addition, a discussion of the future of intestinal ischemia-reperfusion research is provided to place some context on the areas likely to provide the greatest benefit from continued research of ischemia-reperfusion injury.

Testing stem cell therapy in a rat model of inflammatory bowel disease: role of bone marrow stem cells and stem cell factor in mucosal regeneration

BACKGROUND

The gastrointestinal (GI) mucosal cells turnover regularly under physiological conditions, which may be stimulated in various pathological situations including inflammation. Local epithelial stem cells appear to play a major role in such mucosal renewal or pathological regeneration. Less is clear about the involvement of multipotent stem cells from blood in GI repair. We attempted to explore a role of bone marrow mesenchymal stromal cells (BMMSCs) and soluble stem cell factor (SCF) in GI mucosa regeneration in a rat model of inflammatory bowel diseases (IBD).

METHODS

BMMSCs labelled with the fluorescent dye PKH26 from donor rats were transfused into rats suffering indomethacin-induced GI injury. Experimental effects by BMMSCs transplant and SCF were determined by morphometry of intestinal mucosa, double labeling of PKH26 positive BMMSCs with endogenous proliferative and intestinal cell markers, and western blot and PCR analyses of the above molecular markers in the recipient rats relative to controls.

RESULTS

PKH26 positive BMMSCs were found in the recipient mucosa, partially colocalizing with the proliferating cell nuclear antigen (PCNA), Lgr5, Musashi-1 and ephrin-B3. mRNA and protein levels of PCNA, Lgr5, Musashi-1 and ephrin-B3 were elevated in the intestine in BMMSCs-treated rats, most prominent in the BMMSCs-SCF co-treatment group. The mucosal layer and the crypt layer of the small intestine were thicker in BMMSCs-treated rats, more evident in the BMMSCs-SCF co-treatment group.

CONCLUSION

BMMSCs and SCF participate in but may play a synergistic role in mucosal cell regeneration following experimentally induced intestinal injury. Bone marrow stem cell therapy and SCF administration may be of therapeutic value in IBD.

Testing stem cell therapy in a rat model of inflammatory bowel disease: role of bone marrow stem cells and stem cell factor in mucosal regeneration

BACKGROUND

The gastrointestinal (GI) mucosal cells turnover regularly under physiological conditions, which may be stimulated in various pathological situations including inflammation. Local epithelial stem cells appear to play a major role in such mucosal renewal or pathological regeneration. Less is clear about the involvement of multipotent stem cells from blood in GI repair. We attempted to explore a role of bone marrow mesenchymal stromal cells (BMMSCs) and soluble stem cell factor (SCF) in GI mucosa regeneration in a rat model of inflammatory bowel diseases (IBD).

METHODS

BMMSCs labelled with the fluorescent dye PKH26 from donor rats were transfused into rats suffering indomethacin-induced GI injury. Experimental effects by BMMSCs transplant and SCF were determined by morphometry of intestinal mucosa, double labeling of PKH26 positive BMMSCs with endogenous proliferative and intestinal cell markers, and western blot and PCR analyses of the above molecular markers in the recipient rats relative to controls.

RESULTS

PKH26 positive BMMSCs were found in the recipient mucosa, partially colocalizing with the proliferating cell nuclear antigen (PCNA), Lgr5, Musashi-1 and ephrin-B3. mRNA and protein levels of PCNA, Lgr5, Musashi-1 and ephrin-B3 were elevated in the intestine in BMMSCs-treated rats, most prominent in the BMMSCs-SCF co-treatment group. The mucosal layer and the crypt layer of the small intestine were thicker in BMMSCs-treated rats, more evident in the BMMSCs-SCF co-treatment group.

CONCLUSION

BMMSCs and SCF participate in but may play a synergistic role in mucosal cell regeneration following experimentally induced intestinal injury. Bone marrow stem cell therapy and SCF administration may be of therapeutic value in IBD.

Intestinal stem cells and stem cell-based therapy for intestinal diseases

Currently, many gastrointestinal diseases are a major reason for the increased mortality rate of children and adults every year. Additionally, these patients may cope with the high cost of the parenteral nutrition (PN), which aids in the long-term survival of the patients. Other treatment options include surgical lengthening, which is not sufficient in many cases, and intestinal transplantation. However, intestinal transplantation is still accompanied by many challenges, including immune rejection and donor availability, which may limit the transplant's success. The development of more safe and promising alternative treatments for intestinal diseases is still ongoing. Stem cell-based therapy (SCT) and tissue engineering (TE) appear to be the next promising choices for the regeneration of the damaged intestine. However, suitable stem cell source is required for the SCT and TE process. Thus, in this review we discuss how intestinal stem cells (ISCs) are a promising cell source for small intestine diseases. We will also discuss the different markers were used to identify ISCs. Moreover, we discuss the dominant Wnt signaling pathway in the ISC niche and its involvement in some intestinal diseases. Additionally, we discuss ISC culture and expansion, which are critical to providing enough cells for SCT and TE. Finally, we conclude and recommend that ISC isolation, culture and expansion should be considered when SCT is a treatment option for intestinal disorders. Therefore, we believe that ISCs should be considered a cell source for SCT for many gastrointestinal diseases and should be highlighted in future clinical applications.

Predicting disease severity of necrotizing enterocolitis: how to identify infants for future novel therapies

Necrotizing enterocolitis (NEC) remains a very devastating problem within the very low birth weight neonatal population. Several experimental therapies are being tested in animal models and soon may be ready for human trials. Despite this progress, we currently have no way to identify infants who would be optimal targets for therapy. Specifically, we are unable to predict which infants will progress to the more severe Bell's stage of disease that may necessitate surgery. Ideally, an algorithm could be constructed that would encompass multiple neonatal and maternal risk factors as well as potential biologic markers of disease so that these infants could be identified in a more timely fashion. This review summarizes the known risk factors and biomarkers of disease in hopes of stimulating clinical research to identify such an “early warning” NEC algorithm.

Heparin-binding epidermal growth factor-like growth factor restores Wnt/β-catenin signaling in intestinal stem cells exposed to ischemia/reperfusion injury

BACKGROUND

We have previously demonstrated that heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) protects the intestines from injury in several different experimental animal models. In the current study, we investigated whether the ability of HB-EGF to protect the intestines from ischemia/reperfusion (I/R) injury was related to its effects on Wnt/β-catenin signaling in intestinal stem cells (ISC).

METHODS

Lucien-rich repeat-containing G-protein-coupled receptor 5 (LGR5)-enhanced green fluorescent protein (EGFP) transgenic (TG) mice with fluorescently labeled ISC, as well as the same mice treated with intraluminal HB-EGF or genetically engineered to overexpress HB-EGF, were exposed to segmental mesenteric artery occlusion (sMAO) to the terminal ilium. Wnt/β-catenin signaling was evaluated using immunofluorescent staining and Western blotting.

RESULTS

LGR5 expression and Wnt/β-catenin signaling in the ISC of the terminal ilium of LGR5-EGFP TG mice was significantly reduced 24 hours after sMAO. Intraluminal administration of HB-EGF or HB-EGF overexpression in these mice led to preservation of LGR5 expression and Wnt/β-catenin signaling.

CONCLUSION

These data show that HB-EGF preserves Wnt/β-catenin signaling in ISC after I/R injury.

Heparin-binding EGF-like growth factor (HB-EGF) therapy for intestinal injury: Application and future prospects

Throughout the past 20 years, we have been investigating the potential therapeutic roles of heparin-binding EGF-like growth factor (HB-EGF), a member of the epidermal growth factor family, in various models of intestinal injury including necrotizing enterocolitis (NEC), intestinal ischemia/reperfusion (I/R) injury, and hemorrhagic shock and resuscitation (HS/R). Our studies have demonstrated that HB-EGF acts as an effective mitogen, a restitution-inducing reagent, a cellular trophic factor, an anti-apoptotic protein and a vasodilator, via its effects on various cell types in the intestine. In the current paper, we have reviewed the application and therapeutic effects of HB-EGF in three classic animal models of intestinal injury, with particular emphasis on its protection of the intestines from NEC. Additionally, we have summarized the protective functions of HB-EGF on various target cells in the intestine. Lastly, we have provided a brief discussion focusing on the future development of HB-EGF clinical applications for the treatment of various forms of intestinal injury including NEC.

Application of three-dimensional imaging to the intestinal crypt organoids and biopsied intestinal tissues

Two-dimensional (2D) histopathology is the standard analytical method for intestinal biopsied tissues; however, the role of 3-dimensional (3D) imaging system in the analysis of the intestinal tissues is unclear. The 3D structure of the crypt organoids from the intestinal stem cell culture and intestinal tissues from the donors and recipients after intestinal transplantation was observed using a 3D imaging system and compared with 2D histopathology and immunohistochemistry. The crypt organoids and intestinal tissues showed well-defined 3D structures. The 3D images of the intestinal tissues with acute rejection revealed absence of villi and few crypts, which were consistent with the histopathological features. In the intestinal transplant for megacystis microcolon intestinal hypoperistalsis syndrome, the donor's intestinal tissues had well-developed nerve networks and interstitial cells of Cajal (ICCs) in the muscle layer, while the recipient's intestinal tissues had distorted nerve network and the ICCs were few and sparsely distributed, relative to those of the donor. The 3D images showed a clear spatial relationship between the microstructures of the small bowel and the features of graft rejection. In conclusion, integration of the 3D imaging and 2D histopathology provided a global view of the intestinal tissues from the transplant patients.

Autologous gastrointestinal reconstruction: review of the optimal nontransplant surgical options for adults and children with short bowel syndrome

Short bowel syndrome (SBS) results in loss of absorptive capacity of the development of gut, leading to malabsorption due to protein, energy, fluid, and electrolyte loss and imbalance while on enteral diet alone. Various nonsurgical and surgical therapeutic options that have emerged improve the survival outcome following SBS in both children and adults. An individualized, complex multidisciplinary approach to medical and surgical intestinal rehabilitation is needed to provide an opportunity for enteral autonomy to be possible in a patient with SBS. The remnant bowel plays a very pivotal role in autologous gastrointestinal reconstruction (AGIR) surgery. Intestinal transplantation, although promising and potentially life-saving for SBS, should be reserved for patients with failed AGIR or those who have no prospect for autologous enteral autonomy. This article reviews the evolution of nontransplant surgical management of patients with SBS.

Heparin-binding EGF-like growth factor protects intestinal stem cells from injury in a rat model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an often catastrophic disease that typically affects premature newborns. Although the exact etiology of NEC is uncertain, the disease is associated with formula feeding, bacterial colonization of the gut, hypoxia and hypoperfusion. In light of the pathogenesis of NEC, the integrity and function of the intestinal mucosa has a major defensive role against the initiation of NEC. Various forms of intestinal injury, including NEC, injure the intestinal epithelial cell (IEC) lineages, including the intestinal stem cells (ISCs), thereby disrupting the normal homeostasis needed to maintain gut barrier function. In the current study, we examined the effects of heparin-binding EGF-like growth factor (HB-EGF) administration on enterocytes, goblet cells, neuroendocrine cells and ISCs in a newborn rat model of experimental NEC. We also examined the cytoprotective effects of HB-EGF on ISCs in in vitro cell cultures and in ex vivo crypt-villous organoid cultures. We found that HB-EGF protects all IEC lineages, including ISCs, from injury. We further found that HB-EGF protects isolated ISCs from hypoxic injury in vitro, and promotes ISC activation and survival, and the expansion of crypt transit-amplifying cells, in ex vivo crypt-villous organoid cultures. The protective effects of HB-EGF were dependent on EGF receptor activation, and were mediated via the MEK1/2 and PI3K signaling pathways. These results show that the intestinal cytoprotective effects of HB-EGF are mediated, at least in part, through its ability to protect ISCs from injury.

Mesenchymal stem cell therapy in necrotizing enterocolitis: a rat study

We evaluated the potential therapeutic use of exogenous human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in an experimental rat model of necrotizing enterocolitis (NEC). Thirty-six newborn Sprague-Dawley rats were randomly divided into three groups: NEC, NEC + hBM-MSC, and a control (control and control + hBM-MSC). NEC was induced by enteral formula feeding, exposure to hypoxia-hyperoxia, and cold stress. After NEC was induced, iron-labeled hBM-MSCs were administered by intraperitoneal injection. All pups were killed on the fourth day following injection, and the terminal ileum was excised for a histopathological and immunohistochemical evaluation. The pups in the NEC + hBM-MSC group showed significant weight gains and improvements in their clinical sickness scores (p < 0.01). Bowel damage severity observed in the histopathological evaluation was significantly lower in the NEC + hBM-MSC group than that in the NEC group (p = 0.012). The number of MSCs homing to the bowel was significantly higher in the NEC + hBM-MSC group than that in the control + hBM-MSC group. In conclusion, this is the first study that has evaluated the effectiveness of hBM-MSCs in a neonatal rat NEC model. MSCs reduced histopathological damage significantly.

ES, iPS, MSC, and AFS cells. Stem cells exploitation for Pediatric Surgery: current research and perspective

Despite the advancements that have been made in treating infants with congenital malformations, these still represent a major cause of disease and death during the first years of life and childhood. Regeneration of natural tissue from living cells to restore damaged tissues and organs is the main purpose of regenerative medicine. This relatively new field has emerged by the combination of tissue engineering and stem cell transplantation as a possible strategy for the replacement of damaged organs or tissues. This review would like to offer an insight on the latest evolution of stem cells with a glance at their possible application for regenerative medicine, particularly in the Paediatric Surgery field.

Present status and perspectives of stem cell-based therapies for gastrointestinal diseases

In recent years the interest in stem cell-based therapies for gastrointestinal injury has been increasing continuously. From the clinical point of view, transplantation of bone marrow derived stem cells may represent an alternative therapy for gastrointestinal injury, such as radioactive injury, inflammatory bowel disease, and other refractory gastrointestinal tract injury. There were several reports indicated that bone marrow derived stem cells located in the injured gastrointestinal tract and contributed to its regeneration by differentiating into functional epithelia cells or infusing with the gastrointestinal stem cells. Although the concept of cell-based therapy for various diseases of the gastrointestinal is widely accepted, the practical approach in humans remains difficult. Here we discussed the recent published data on clinical and experimental bone marrow stem cell transplantation and the possible role of stem cells in gastrointestinal tissue repair.