Amniotic fluid stem cell migration after intraperitoneal injection in pup rats: implication for therapy

Thrombin-preconditioned mesenchymal stromal cell-derived extracellular vesicles attenuate experimental necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a critical gastrointestinal disease in preterm infants, for which no specific treatment is established. We previously demonstrated that thrombin-preconditioned mesenchymal stromal cell-derived extracellular vesicles (thMSC-EVs) enhance protection against other neonatal tissue injuries. Therefore, this study aimed to evaluate the therapeutic potential of thMSC-EVs in modified in vitro, in vivo, and organoid models of NEC.

METHODS

In vitro, the effects of thMSC-EVs and naïveMSC-EVs were compared in hyperosmotic, ischemic, and hypothermic (HIT)-stressed IEC-6 cells and LPS-treated peritoneal macrophages. In vivo, NEC was induced in P4 mouse pups by three cycles of formula feeding, oral LPS administration, hypoxia, and hypothermia, followed by overnight dam care. 2 × 109 thMSC-EVs were intraperitoneally administered daily for three days, and the therapeutic effects were assessed macroscopically, histologically, and biochemically. NEC mouse-derived organoids were established to evaluate the thMSC-EVs' effect in mature enterocytes. LC-MS/MS was performed to analyze the EV proteomics.

RESULTS

In vitro, compared with naïveMSC-EVs, thMSC-EVs significantly improved cellular viability in HIT-induced IEC-6 cells and reduced pro-inflammatory (IL-1α, IL-1β, TNF-α) but increased anti-inflammatory (TGF-b) cytokine levels in LPS-treated peritoneal macrophages. In vivo, thMSC-EVs significantly attenuated clinical symptoms, reduced intestinal damage, and retained intestinal stem cell markers, showing more significant localization in NEC-induced intestines than in healthy intestines. In NEC mouse-derived organoids, thMSC-EVs significantly increased OLFM4 and claudin-4 expression and reduced stress-related markers such as sucrase-isomaltase, defensin, and chromogranin A. Proteomic analysis revealed that thMSC-EVs were greater enriched in anti-apoptotic, anti-inflammatory, cell adhesion, and Wnt signaling pathways than naïveMSC-EVs.

CONCLUSION

thMSC-EVs improved cellular viability, reduced apoptosis, attenuated inflammation, and upregulated key intestinal stem cell markers, collectively suggesting their tissue-protective effects and highlighting their potential as a treatment for NEC.

Stem Cells and the Microenvironment: Reciprocity with Asymmetry in Regenerative Medicine

Much of the current research in regenerative medicine concentrates on stem-cell therapy that exploits the regenerative capacities of stem cells when injected into different types of human tissues. Although new therapeutic paths have been opened up by induced pluripotent cells and human mesenchymal cells, the rate of success is still low and mainly due to the difficulties of managing cell proliferation and differentiation, giving rise to non-controlled stem cell differentiation that ultimately leads to cancer. Despite being still far from becoming a reality, these studies highlight the role of physical and biological constraints (e.g., cues and morphogenetic fields) placed by tissue microenvironment on stem cell fate. This asks for a clarification of the coupling of stem cells and microenvironmental factors in regenerative medicine. We argue that extracellular matrix and stem cells have a causal reciprocal and asymmetric relationship in that the 3D organization and composition of the extracellular matrix establish a spatial, temporal, and mechanical control over the fate of stem cells, which enable them to interact and control (as well as be controlled by) the cellular components and soluble factors of microenvironment. Such an account clarifies the notions of stemness and stem cell regeneration consistently with that of microenvironment.

Human Amniotic Fluid Stem Cells Ameliorate Thioglycollate-Induced Peritonitis by Increasing Tregs in Mice

Mesenchymal stem cells (MSCs) affect immune cells and exert anti-inflammatory effects. Human amniotic fluid stem cells (hAFSCs), a type of MSCs, have a high therapeutic effect in animal models of inflammation-related diseases. hAFSCs can be easily isolated and cultured from amniotic fluid, which is considered a medical waste. Hence, amniotic fluid can be a source of cells for MSC therapy of inflammatory diseases. However, the effect of hAFSCs on acquired immunity in vivo, especially on regulatory T cells, has not yet been fully elucidated. Therefore, in this study, we aimed to understand the effects of hAFSCs on acquired immunity, particularly on regulatory T cells. We showed that hAFSCs ameliorated the thioglycollate-induced inflammation by forming aggregates with host immune cells, such as macrophages, T cells, and B cells in the peritoneal cavity. Further, the regulatory T cells increased in the peritoneal cavity. These results indicated that, in addition to helping the innate immunity, hAFSCs could also aid the acquired immune system in vivo against inflammation-related diseases by increasing regulatory T cells.

Stem cells in neonatal diseases: An overview

Preterm birth and its common complications are major causes of infant mortality and long-term morbidity. Despite great advances in understanding the pathogenesis of neonatal diseases and improvements in neonatal intensive care, effective therapies for the prevention or treatment for these conditions are still lacking. Stem cell (SC) therapy is rapidly emerging as a novel therapeutic tool for several diseases of the newborn with encouraging pre-clinical results that hold promise for translation to the bedside. The utility of different types of SCs in neonatal diseases is being explored. SC therapeutic efficacy is closely associated with its secretome-conditioned media and SC-derived extracellular vesicles, and a subsequent paracrine action in response to tissue injuries. In the current review, we summarize the pre-clinical and clinical studies of SCs and its secretome in diverse preterm and term birth-related diseases, thereby providing new insights for future therapies in neonatal medicine.

Human placental-derived stem cell therapy ameliorates experimental necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a life-threatening intestinal disease, is becoming a larger proportionate cause of morbidity and mortality in premature infants. To date, therapeutic options remain elusive. Based on recent cell therapy studies, we investigated the effect of a human placental-derived stem cell (hPSC) therapy on intestinal damage in an experimental NEC rat pup model. NEC was induced in newborn Sprague-Dawley rat pups for 4 days via formula feeding, hypoxia, and LPS. NEC pups received intraperitoneal (ip) injections of either saline or hPSC (NEC-hPSC) at 32 and 56 h into NEC induction. At 4 days, intestinal macroscopic and histological damage, epithelial cell composition, and inflammatory marker expression of the ileum were assessed. Breastfed (BF) littermates were used as controls. NEC pups developed significant bowel dilation and fragility in the ileum. Further, NEC induced loss of normal villi-crypt morphology, disruption of epithelial proliferation and apoptosis, and loss of critical progenitor/stem cell and Paneth cell populations in the crypt. hPSC treatment improved macroscopic intestinal health with reduced ileal dilation and fragility. Histologically, hPSC administration had a significant reparative effect on the villi-crypt morphology and epithelium. In addition to a trend of decreased inflammatory marker expression, hPSC-NEC pups had increased epithelial proliferation and decreased apoptosis when compared with NEC littermates. Further, the intestinal stem cell and crypt niche that include Paneth cells, SOX9+ cells, and LGR5+ stem cells were restored with hPSC therapy. Together, these data demonstrate hPSC can promote epithelial healing of NEC intestinal damage.NEW & NOTEWORTHY These studies demonstrate a human placental-derived stem cell (hPSC) therapeutic strategy for necrotizing enterocolitis (NEC). In an experimental model of NEC, hPSC administration improved macroscopic intestinal health, ameliorated epithelial morphology, and supported the intestinal stem cell niche. Our data suggest that hPSC are a potential therapeutic approach to attenuate established intestinal NEC damage. Further, we show hPSC are a novel research tool that can be utilized to elucidate critical neonatal repair mechanisms to overcome NEC.

Amnion-Derived Multipotent Progenitor Cells Suppress Experimental Optic Neuritis and Myelitis

The human amnion has been used for decades in wound healing, particularly burns. Amnion epithelial cells (AECs) have been the focus of extensive research based on their possible pluripotent differentiation ability. A novel, cultured cell population derived from AECs, termed human amnion-derived multipotent progenitor (AMP) cells, secrete numerous cytokines and growth factors that enhance tissue regeneration and reduce inflammation. This AMP cell secretome, termed ST266, is a unique biological solution that accumulates in eyes and optic nerves following intranasal delivery, resulting in selective suppression of optic neuritis in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, but not myelitis at the administered dose. We tested the hypothesis that systemic AMP cell administration could suppress both optic neuritis and myelitis in EAE. Intravenous and intraperitoneal administration of AMP cells significantly reduced ascending paralysis and attenuated visual dysfunction in EAE mice. AMP cell treatment increased retinal ganglion cell (RGC) survival and decreased optic nerve inflammation, with variable improvement in optic nerve demyelination and spinal cord inflammation and demyelination. Results show systemic AMP cell administration inhibits RGC loss and visual dysfunction similar to previously demonstrated effects of intranasally delivered ST266. Importantly, AMP cells also promote neuroprotective effects in EAE spinal cords, marked by reduced paralysis. Protective effects of systemically administered AMP cells suggest they may serve as a potential novel treatment for multiple sclerosis.

Repair of rat cranial bone defect by using amniotic fluid-derived mesenchymal stem cells in polycaprolactone fibrous scaffolds and platelet-rich plasma

Introduction: Tissue regenerative medicine strategies, as a promising alternative has become of major interest to the reconstruction of critical size bone defects. This study evaluated the effects of the simultaneous application of polycaprolactone (PCL), amniotic fluid mesenchymal stem cells (AF-MSCs) and platelet-rich plasma (PRP) on the repair of rat cranial bone defects. Methods: The AF-MSCs were isolated at the end of the second week of pregnancy in rats. PRP obtained from rat blood and the random PCL fibrous scaffolds were prepared using the electrospinning method. Circular full thickness (5 mm) bone defects were developed on both sides of the parietal bones (animal number=24) and the scaffolds containing AF-MSCs and PRP were implanted in the right lesions. Thereafter, after eight weeks the histological and immunohistochemistry studies were performed to evaluate the bone formation and collagen type I expression. Results: The spindle-shaped mesenchymal stem cells were isolated and the electron microscope images indicated the preparation of a random PCL scaffold. Immunohistochemical findings showed that collagen type I was expressed by AF-MSCs cultured on the scaffold. The results of hematoxylin and eosin (H&E) staining indicated the formation of blood vessels in the presence of PRP. Additionally, immunofluorescence findings suggested that PRP had a positive effect on collagen type I expression. Conclusion: The simultaneous application of fibrous scaffold + AF-MSCs + PRP has positive effects on bone regeneration. This study showed that PRP can affect the formation of new blood vessels in the scaffold transplanted in the bone defect.

Investigating the route of administration and efficacy of adipose tissue-derived mesenchymal stem cells and conditioned medium in type 1 diabetic mice

Type 1 diabetes (T1D) is a chronic autoimmune disease destroying the insulin-producing beta cells. Recently, stem cell therapy has been tested to treat T1D. In the present study, we aim to investigate the effects of intraperitoneal and intravenous infusion of multipotent mesenchymal stem/stromal cells (MSCs) and MSC-conditioned medium (MSC-CM) in an experimental model of diabetes, induced by multiple injections of Streptozotocin (STZ). The adipose tissue-derived MSC and MSC-CM were isolated from C57Bl/6 male mice and characterized. Later, MSC and MSC-CM were injected intraperitoneally or intravenously into mice. The blood glucose, urinary glucose, and body weight were measured, and the percentages of CD4+ CD25+ FOXP3+ T cells as well as the levels of IFN-γ, TGF-β, IL-4, IL-17, and IL-10 were evaluated. Our results showed that both intraperitoneal and intravenous infusions of MSC and MSC-CM could decrease the blood glucose, recover pancreatic islets, and increase the levels of insulin-producing cells. Furthermore, the percentage of CD4+ CD25+ FOXP3+ T cells was increased after intraperitoneal injection of MSC or MSC-CM and intravenous injection of MSCs. After intraperitoneal injection of the MSC and MSC-CM, the levels of inflammatory cytokines reduced, while the levels of anti-inflammatory cytokines increased. Together current data showed that although both intraperitoneal and intravenous administration had beneficial effects on T1D animal model, but intraperitoneal injection of AD-MSC and AD-MSC-CM was more effective than systemic administration.

Stem cell therapy for preventing neonatal diseases in the 21st century: Current understanding and challenges

Diseases of the preterm newborn such as bronchopulmonary dysplasia, necrotizing enterocolitis, cerebral palsy, and hypoxic-ischemic encephalopathy continue to be major causes of infant mortality and long-term morbidity. Effective therapies for the prevention or treatment for these conditions are still lacking as recent clinical trials have shown modest or no benefit. Stem cell therapy is rapidly emerging as a novel therapeutic tool for several neonatal diseases with encouraging pre-clinical results that hold promise for clinical translation. However, there are a number of unanswered questions and facets to the development of stem cell therapy as a clinical intervention. There is much work to be done to fully elucidate the mechanisms by which stem cell therapy is effective (e.g., anti-inflammatory versus pro-angiogenic), identifying important paracrine mediators, and determining the timing and type of therapy (e.g., cellular versus secretomes), as well as patient characteristics that are ideal. Importantly, the interaction between stem cell therapy and current, standard-of-care interventions is nearly completely unknown. In this review, we will focus predominantly on the use of mesenchymal stromal cells for neonatal diseases, highlighting the promises and challenges in clinical translation towards preventing neonatal diseases in the 21st century.

Cell-based therapy for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is an example of interstitial lung diseases that is characterized by chronic, progressive, and fibrotic lung injuries. During lung fibrosis, normal healthy lung tissues are replaced by remarkably destroyed alveolar architecture and altered extracellular cell matrix. These changes eventually cause severe disruption of the tightly-controlled gas exchange process and reduction of lung compliance that ultimately lead to both respiratory failure and death. In the last decade, progress has been made toward understanding the pathogenesis of pulmonary fibrosis, and two novel disease-modifying therapies were approved. However, finding more effective treatments for pulmonary fibrosis is still a challenge, with its incidence continues to increase globally, which is associated with significantly high mortality, morbidity and economical healthcare burden. Different stem cell types have recently emerged as a promising therapy for human diseases, including lung fibrosis, with numerous studies on the identification, characterization, proliferation and differentiation of stem cells. A large body of both basic and pre-clinical research on stem cells has been recently translated to patient care worldwide. Herein, we review recent advances in our understanding of the pathophysiology of IPF, and types of cells used in IPF cell-based therapies, including alveolar and mixed lung epithelial cells, different stem cell types (MSCs, ADSCs, IPSCs…etc.), endogenous lung tissue-specific stem cells, and circulating endothelial progenitors (EPCs). We also discuss recent studies on the applications of these cells in IPF therapy and their delivery routes, effective doses for cell therapy, and timing of delivery. Finally, we discuss attractive recent and current clinical trials conducted on cell-based therapy for IPF.

Advances in stem cell therapy for male stress urinary incontinence

INTRODUCTION

Among the several options that have been proposed in recent years for the management of male stress urinary incontinence (SUI), stem cell therapy represents a new frontier in treatment. The aim of this paper is to update the current status of stem cell therapy in animal and human studies for the management of iatrogenic male SUI.

AREAS COVERED

A literature review was conducted based on MEDLINE/PubMed searches for English articles using a combination of the following keywords: stem cell therapy, urinary incontinence, prostatectomy, regenerative medicine, mesenchymal stem cells.

EXPERT OPINION

The few studies reported in the literature have demonstrated short-term safety and promising results of stem cell therapy in treating male SUI. However, many aspects need to be clarified before stem cell therapy can be introduced into daily urologic practice. In fact, important issues such as the limitations of these studies in terms of small sample sizes and short follow-ups, the incomplete knowledge of the mechanism of action of stem cells, the technical details regarding the delivery method and the best sources of stem cells, the safety risks regarding genomic or epigenetic changes and potential immune reactions in the longer term need to be identified in more stringent clinical trials.

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.

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).

Multiplacenta derived stem cell/cytokine treatment increases survival time in a mouse model with radiation-induced bone marrow damage

Nuclear Warfare and nuclear leakage can result in a large number of patients with radiation-induced bone marrow damage. Based on the fact that hematopoietic stem cells and hematopoietic growth factors are characterized as a novel strategy for therapy, the aim of this study was to explore a safe and routine stem cell/cytokine therapeutic strategy. Allogeneic multiplacenta derived hematopoietic and mesenchymal stem cells/cytokines were intraperitoneally injected into a moderate dose of total body irradiation-induced mouse bone marrow damage model a single time. Then, the mouse posttransplantation survival time, peripheral blood hemoglobin count, bone marrow architecture, and donor cell engraftment were assessed. Each mouse that received placenta-derived stem cells exhibited positive donor hematopoietic and mesenchymal stem cell engraftment both in the bone marrow and peripheral blood after transplantation. The peripheral blood hemoglobin count and survival time were greater in the group with the combined treatment of multiplacenta-derived stem cells and cytokines, compared with model-only controls (both P < 0.001). The blood smear mesenchymal/hematopoietic stem cell count was significantly higher in the combined treatment group than in the mice treated only with placenta-derived cells (28.08 ± 5.824 vs. 20.40 ± 5.989, P < 0.001; 7.74 ± 2.153 vs. 4.23 ± 1.608, P < 0.001, respectively). However, there was no marked change on the bone marrow pathology of any of the experimental mice after the transplantation. These results indicate that for radiation-induced bone marrow damage treatment, multiplacenta-derived stem cells and cytokines can increase the life span of model mice and delay but not abrogate the disease progression. Intraperitoneally transplanted stem cells can survive and engraft into the host body through the blood circulation. Improvement of peripheral blood hemoglobin levels, but not the bone marrow architecture response, probably explains the increase in survival time observed in this study.

Intraperitoneal Injection of Multiplacentas Pooled Cells Treatment on a Mouse Model with Aplastic Anemia

Coinfusion of hematopoietic and mesenchymal stem cells is more effective than hematopoietic stem cell transplantation alone. It is necessary to explore a safe and routine mixed stem cell intraperitoneal transplantation method. Multiplacentas pooled cells were intraperitoneally injected into a radiation- and immunity-induced mouse aplastic anemia model with single time. Then, mouse survival time, peripheral blood hemoglobin count, bone marrow architecture, and donor cell engraftment were assessed. The recipient mouse exhibited donor cell engraftment in both bone marrow and peripheral blood. Survival time and peripheral blood hemoglobin count increased in placenta pooled cells treated mice, compared with model-only controls (P = 0.048 and P = 0.000, resp.). However, placentas pooled cells failed to cause a significant decrease in bone marrow pimelosis area (P = 0.357). Intraperitoneally transplanted multiplacentas pooled cells can survive and engraft into a host body through blood circulation, which can increase the life span of an aplastic anemia model mice, and delay but not abrogate the development of aplastic anemia. Furthermore, they appear to play a role in increasing peripheral blood hemoglobin level response for increasing the life span of aplastic anemia model mice.

Cell-based therapies for the treatment of idiopathic pulmonary fibrosis (IPF) disease

INTRODUCTION

During the last few decades, cell-based therapies have shown great potential to treat patients with lung diseases. It has been proposed that the administration of cells into an injured lung could be considered as a therapeutic method to repair and replace lost lung tissue. Using this method, transplanted cells with the ability to proliferate and differentiate into alveolar cells, have been suggested as a therapeutic strategy for IPF treatment.

AREAS COVERED

In this review, the latest investigations using various types of cells for IPF therapy have been presented. The cells studied for cell-based therapies in IPF are lung alveolar epithelial cells, lung resident stem cells and exogenous adult stem cells such as MSCs.

EXPERT OPINION

After many years of investigation, the use of cell-based therapies to treat IPF is still at the experimental phase. Problems include bioethical issues, safety of cell transplantation, routes of delivery and the dose and timing of administration. Further investigations are necessary to establish the best strategy for using cell-based therapies effectively for the treatment of IPF.

A Mini Overview of Isolation, Characterization and Application of Amniotic Fluid Stem Cells

Amniotic fluid represents rich sources of stem cells that can be used in treatments for a wide range of diseases. Amniotic fluid- stem cells have properties intermediate between embryonic and adult mesenchymal stem cells which make them particularly attractive for cellular regeneration and tissue engineering. Furthermore, scientists are interested in these cells because they come from the amniotic fluid that is routinely discarded after birth. In this review we give a brief introduction of amniotic fluid followed by a description of the cells present within this fluid and aim to summarize the all existing isolation methods, culturing, characterization and application of these cells. Finally, we elaborate on the differentiation and potential for these cells to promote regeneration of various tissue defects, including fetal tissue, the nervous system, heart, lungs, kidneys, bones, and cartilage in the form of table.

Improved skin flap survival in venous ischemia-reperfusion injury with the use of adipose-derived stem cells

INTRODUCTION

The purpose of this study was to investigate the efficacy of stem cell therapy as an adjuvant treatment for congested skin flap.

METHOD

Sprague-Dawley rats (n = 21) were randomized into three groups. In group I, the flap was sutured without venous ischemia. In group II, the vein was selectively clamped for 4 hours, and complete medium was administered upon clamp removal. In group III, ADSCs were administered upon removing the clamp. On postoperative day 7, the survival areas and the histopathologic findings were assessed. In addition, the expression of heme oxygenase (HO)-1 and nuclear factor (NF)-κB was assessed using immunofluorescent staining and western blot analyses.

RESULTS

Compared with group II, group III showed significantly increased flap survival (31.2% ± 11.9% vs. 51.6% ± 13.6%, P < 0.05). The degree of histological abnormalities was significantly lower in group III than in group II (9.38% ± 1.39 vs. 6.46% ± 2.57, P < 0.05). In addition, in group III, the expression of NF-κB was significantly lower (0.51 ± 0.21 vs. 0.34 ± 0.21, P < 0.05), whereas that of HO-1 was significantly higher (0.25 ± 0.11 vs. 0.43 ± 0.18, P < 0.01). Immunofluorescent staining also showed more HO-1-positive cells in group III than in group II (10.9% ± 1.6% vs. 16.0% ± 1.7%, P < 0.01).

CONCLUSION

Our study demonstrated that treatment with ADSCs significantly increased flap survival in venous ischemia-reperfusion conditions. Further investigation of these protective effects and optimization of the treatment protocol could make cell therapy a viable treatment.

Safety of Intraperitoneal Injection of Adipose Tissue-Derived Autologous Mesenchymal Stem Cells in Cats

Background

Chronic inflammatory diseases are common in cats and mesenchymal stem cells (MSC) are a promising therapeutic approach for management of these disorders. The purpose of this study was to evaluate the safety of intraperitoneal injection of MSC in cats.

Hypothesis

Intrapertioneal injection of autologous MSC in cats is safe.

Animals

Ten healthy adult purpose‐bred cats.

Methods

Mesenchymal stem cells were isolated from subcutaneous adipose tissue collected during ovariohysterectomy and characterized for expression of CD90, CD105 and CD44 and trilineage differentiation. Three weeks postoperatively a complete blood count, serum chemistry profile, urinalysis, and abdominal ultrasound were performed. Five cats then received 1 × 10⁶ of autologous MSC/kg of body weight intraperitoneally with ultrasound guidance; 5 additional cats were sham injected. Cats were monitored for 6 weeks with daily physical examinations and weekly clinicopathological evaluations. Abdominal ultrasonography was repeated at weeks 1 and 5 after injection.

Results

Serious adverse effects were not observed in any MSC‐injected cat. Two animals developed transient lethargy and decreased activity. Jejunal lymph node size was increased in MSC‐injected cats compared to controls at weeks 1 (1.38 ± 0.25 versus 0.88 ± 0.25 cm²; P = .036) and 5 (1.75 ± 0.82 versus 0.79 ± 0.12 cm²; P = .047). A hyperechoic renal segmental cortical lesion was observed in 1 MSC‐injected cat.

Conclusions and Clinical Relevance

Intraperitoneal MSC injection was well tolerated with only mild, self‐limiting adverse effects being observed in 2 cats. This route provides a safe means of administration for cell‐based treatment in cats.

Immune regulatory properties of CD117(pos) amniotic fluid stem cells vary according to gestational age

Amniotic Fluid Stem (AFS) cells are broadly multipotent fetal stem cells derived from the positive selection and ex vivo expansion of amniotic fluid CD117/c-kit(pos) cells. Considering the differentiation potential in vitro toward cell lineages belonging to the three germ layers, AFS cells have raised great interest as a new therapeutic tool, but their immune properties still need to be assessed. We analyzed the in vitro immunological properties of AFS cells from different gestational age in coculture with T, B, and natural killer (NK) cells. Nonactivated (resting) first trimester-AFS cells showed lower expression of HLA class-I molecules and NK-activating ligands than second and third trimester-AFS cells, whose features were associated with lower sensitivity to NK cell-mediated lysis. Nevertheless, inflammatory priming with interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) enhanced resistance of all AFS cell types to NK cytotoxicity. AFS cells modulated lymphocyte proliferation in a different manner according to gestational age: first trimester-AFS cells significantly inhibited T and NK cell proliferation, while second and third trimester-AFS cells were less efficient. In addition, only inflammatory-primed second trimester-AFS cells could suppress B cell proliferation, which was not affected by the first and third trimester-AFS cells. Indolamine 2,3 dioxygenase pathway was significantly involved only in T cell suppression mediated by second and third trimester-AFS cells. Overall, this study shows a number of significant quantitative differences among AFS cells of different gestational age that have to be considered in view of their clinical application.

The potential role of stem cells in the treatment of urinary incontinence

Voiding dysfunction encompasses a wide range of urologic disorders including stress urinary incontinence and overactive bladder that have a detrimental impact on the quality of life of millions of men and women worldwide. In recent years, we have greatly expanded our understanding of the pathophysiology of these clinical conditions. However, current gold standard therapies often provide symptomatic relief without targeting the underlying etiology of disease development. Recently, the use of stem cells to halt disease progression and reverse underlying pathology has emerged as a promising method to restore normal voiding function. Stem cells are classically thought to aid in tissue repair via their ability for multilineage differentiation and self-renewal. They may also exert a therapeutic effect via the secretion of bioactive factors that direct other stem and progenitor cells to the area of injury, and that also possess antiapoptotic, antiscarring, neovascularization, and immunomodulatory properties. Local injections of mesenchymal, muscle-derived, and adipose-derived stem cells have all yielded successful outcomes in animal models of mechanical, nerve, or external urethral sphincter injury in stress urinary incontinence. Similarly, direct injection of mesenchymal and adipose-derived stem cells into the bladder in animal models of bladder overactivity have demonstrated efficacy. Early clinical trials using stem cells for the treatment of stress urinary incontinence in both male and female patients have also achieved promising functional results with minimal adverse effects. Although many challenges remain to be addressed prior to the clinical implementation of this technology, novel stem-cell-based therapies are an exciting potential therapy for voiding dysfunction.

In utero therapy for congenital disorders using amniotic fluid stem cells

Congenital diseases are responsible for over a third of all pediatric hospital admissions. Advances in prenatal screening and molecular diagnosis have allowed the detection of many life-threatening genetic diseases early in gestation. In utero transplantation (IUT) with stem cells could cure affected fetuses but so far in humans, successful IUT using allogeneic hematopoietic stem cells (HSCs), has been limited to fetuses with severe immunologic defects and more recently IUT with allogeneic mesenchymal stem cell transplantation, has improved phenotype in osteogenesis imperfecta. The options of preemptive treatment of congenital diseases in utero by stem cell or gene therapy changes the perspective of congenital diseases since it may avoid the need for postnatal treatment and reduce future costs. Amniotic fluid stem (AFS) cells have been isolated and characterized in human, mice, rodents, rabbit, and sheep and are a potential source of cells for therapeutic applications in disorders for treatment prenatally or postnatally. Gene transfer to the cells with long-term transgenic protein expression is feasible. Recently, pre-clinical autologous transplantation of transduced cells has been achieved in fetal sheep using minimally invasive ultrasound guided injection techniques. Clinically relevant levels of transgenic protein were expressed in the blood of transplanted lambs for at least 6 months. The cells have also demonstrated the potential of repair in a range of pre-clinical disease models such as neurological disorders, tracheal repair, bladder injury, and diaphragmatic hernia repair in neonates or adults. These results have been encouraging, and bring personalized tissue engineering for prenatal treatment of genetic disorders closer to the clinic.

Therapeutic outcomes of transplantation of amniotic fluid-derived stem cells in experimental ischemic stroke

Accumulating preclinical evidence suggests the use of amnion as a source of stem cells for investigations of basic science concepts related to developmental cell biology, but also for stem cells’ therapeutic applications in treating human disorders. We previously reported isolation of viable rat amniotic fluid-derived stem (AFS) cells. Subsequently, we recently reported the therapeutic benefits of intravenous transplantation of AFS cells in a rodent model of ischemic stroke. Parallel lines of investigations have provided safety and efficacy of stem cell therapy for treating stroke and other neurological disorders. This review article highlights the need for investigations of mechanisms underlying AFS cells’ therapeutic benefits and discusses lab-to-clinic translational gating items in an effort to optimize the clinical application of the cell transplantation for stroke.

Comparative Study between Intravenous and Intraperitoneal Stem Cell Therapy in Amiodarone Induced Lung Injury in Rat

Background and Objectives:

The fibrosing form of lung injury (occupational, environmental, infective or drug induced) is associated with significant morbidity and mortality. Amiodarone (AM), often prescribed for control of arrhythmias is considered a potential cause. No effective treatment was confirmed, except lung transplantation. Intravenous (IV) stem cell therapy may produce pulmonary emboli or infarctions. Despite being commonly used in clinical practice, the intraperitoneal (IP.) route has been rarely used for cell delivery. The present study aimed at investigating and comparing the possible effect of IP stem cell therapy (SCT) on pulmonary toxicity versus the intravenous route in a rat model of amiodarone induced lung damage.

Methods and Results:

36 adult male albino rats were divided into 4 groups. Rats of AM group were given 30 mg/kg daily orally for 4 weeks. Rats of IV SCT group were injected with stem cells in the tail vein. Rats of IP SCT group received IP cell therapy. Histological, histochemical, immunohistochemical and morphometric studies were performed. Obstructed bronchioles, overdistended alveoli, reduced type I pneumocytes, increased thickness of alveolar septa and vessels wall besides increased area% of collagen fibers regressed in response to IV and IP SCT. The improvement was more obvious in IV group. The area% of Prussion blue +ve and CD105 +ve cells was significantly higher in IV group.

Conclusions:

Cord blood MSC therapy proved definite amelioration of lung injury ending in fibrosis. The effect of IP SCT was slightly inferior to that of IV SCT, which may be overwhelmed by repeated IP injection.

Amniotic fluid stem cells improve survival and enhance repair of damaged intestine in necrotising enterocolitis via a COX-2 dependent mechanism

OBJECTIVE

Necrotising enterocolitis (NEC) remains one of the primary causes of morbidity and mortality in neonates and alternative strategies are needed. Stem cells have become a therapeutic option for other intestinal diseases, which share some features with NEC. We tested the hypothesis that amniotic fluid stem (AFS) cells exerted a beneficial effect in a neonatal rat model of NEC.

DESIGN

Rats intraperitoneally injected with AFS cells and their controls (bone marrow mesenchymal stem cells, myoblast) were analysed for survival, behaviour, bowel imaging (MRI scan), histology, bowel absorption and motility, immunofluorescence for AFS cell detection, degree of gut inflammation (myeloperoxidase and malondialdehyde), and enterocyte apoptosis and proliferation.

RESULTS

AFS cells integrated in the bowel wall and improved rat survival and clinical conditions, decreased NEC incidence and macroscopic gut damage, improved intestinal function, decreased bowel inflammation, increased enterocyte proliferation and reduced apoptosis. The beneficial effect was achieved via modulation of stromal cells expressing cyclooxygenase 2 in the lamina propria, as shown by survival studies using selective and non-selective cyclooxygenase 2 inhibitors. Interestingly, AFS cells differentially expressed genes of the Wnt/β-catenin pathway, which regulate intestinal epithelial stem cell function and cell migration and growth factors known to maintain gut epithelial integrity and reduce mucosal injury.

CONCLUSIONS

We demonstrated here for the first time that AFS cells injected in an established model of NEC improve survival, clinical status, gut structure and function. Understanding the mechanism of this effect may help us to develop new cellular or pharmacological therapies for infants with NEC.

Stem cells as a potential therapy for necrotizing enterocolitis

INTRODUCTION

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease of neonates, especially those born prematurely, that remains an important cause of morbidity and mortality. Although current treatments such as inotropes, antibiotics and ventilation are supportive, there is an urgent need for novel therapies that specifically target the affected intestine.

AREAS COVERED

We briefly introduce the disease and the effects on intestinal epithelia. We provide a brief description of amniotic fluid stem (AFS) cells, and then describe some recent data in which AFS cells were beneficial in an animal model of NEC and a potential mechanism is described. The effects of AFS cells are compared with data on bone marrow mesenchymal stem cells. The potential implications of these findings for therapy are discussed.

EXPERT OPINION

The current data are promising and demonstrate that stem cells do have an effect in rodent models of NEC. However, the short timescale, limited ability for longitudinal evaluation and uncertain clinical relevance of these models means that there are considerable challenges to be overcome before attempting stem cell therapy in clinical trials. Nevertheless, these data open up novel areas of research into a prevention or therapy for this devastating disease.

Amniotic fluid stem cells restore the muscle cell niche in a HSA-Cre, Smn(F7/F7) mouse model

Mutations in the survival of motor neuron gene (SMN1) are responsible for spinal muscular atrophy, a fatal neuromuscular disorder. Mice carrying a homozygous deletion of Smn exon 7 directed to skeletal muscle (HSA-Cre, Smn(F7/F7) mice) present clinical features of human muscular dystrophies for which new therapeutic approaches are highly warranted. Herein we demonstrate that tail vein transplantation of mouse amniotic fluid stem (AFS) cells enhances the muscle strength and improves the survival rate of the affected animals. Second, after cardiotoxin injury of the Tibialis Anterior, only AFS-transplanted mice efficiently regenerate. Most importantly, secondary transplants of satellite cells (SCs) derived from treated mice show that AFS cells integrate into the muscle stem cell compartment and have long-term muscle regeneration capacity indistinguishable from that of wild-type-derived SC. This is the first study demonstrating the functional and stable integration of AFS cells into the skeletal muscle, highlighting their value as cell source for the treatment of muscular dystrophies.

Substrate elasticity controls cell proliferation, surface marker expression and motile phenotype in amniotic fluid-derived stem cells

The physical cues presented to stem cells by the substrate on or in which they exist have been shown to play a crucial role in regulation of their behavior. Until recently, most research has focused on the effects of substrate elasticity on differentiation capability rather than maintenance of long-term proliferation and plasticity. The main goal of the present study is to study the interaction of amniotic fluid-derived stem (AFS) cells with growth substrata of different elasticity, which may extend their application potentials. Here, we investigate the effects of elastic modulus (E'), on AFS cell proliferation, morphology, cell surface marker expression, and autocrine stimulation of cell migration. AFS cells cultured on substrates of different E' exhibited significant changes in proliferation and morphology. Immunohistochemistry revealed increased expression of cell surface markers associated with mesenchymal stem cells (MSCs) (CD44, CD90, CD105, and N-cadherin) in cells cultured on softer substrates. Additionally, AFS cells cultured on softer substrates induced autocrine stimulation of migration. Therefore, tailoring the elastic modulus of biomaterials to specific stiffness values is an effective method to control stem cell properties, which may modulate the effectiveness of their therapeutic applications.

Applications of amniotic membrane and fluid in stem cell biology and regenerative medicine

The amniotic membrane (AM) and amniotic fluid (AF) have a long history of use in surgical and prenatal diagnostic applications, respectively. In addition, the discovery of cell populations in AM and AF which are widely accessible, nontumorigenic and capable of differentiating into a variety of cell types has stimulated a flurry of research aimed at characterizing the cells and evaluating their potential utility in regenerative medicine. While a major focus of research has been the use of amniotic membrane and fluid in tissue engineering and cell replacement, AM- and AF-derived cells may also have capabilities in protecting and stimulating the repair of injured tissues via paracrine actions, and acting as vectors for biodelivery of exogenous factors to treat injury and diseases. Much progress has been made since the discovery of AM and AF cells with stem cell characteristics nearly a decade ago, but there remain a number of problematic issues stemming from the inherent heterogeneity of these cells as well as inconsistencies in isolation and culturing methods which must be addressed to advance the field towards the development of cell-based therapies. Here, we provide an overview of the recent progress and future perspectives in the use of AM- and AF-derived cells for therapeutic applications.

Intravenous grafts of amniotic fluid-derived stem cells induce endogenous cell proliferation and attenuate behavioral deficits in ischemic stroke rats

We recently reported isolation of viable rat amniotic fluid-derived stem (AFS) cells [1]. Here, we tested the therapeutic benefits of AFS cells in a rodent model of ischemic stroke. Adult male Sprague-Dawley rats received a 60-minute middle cerebral artery occlusion (MCAo). Thirty-five days later, animals exhibiting significant motor deficits received intravenous transplants of rat AFS cells or vehicle. At days 60–63 post-MCAo, significant recovery of motor and cognitive function was seen in stroke animals transplanted with AFS cells compared to vehicle-infused stroke animals. Infarct volume, as revealed by hematoxylin and eosin (H&E) staining, was significantly reduced, coupled with significant increments in the cell proliferation marker, Ki67, and the neuronal marker, MAP2, in the dentate gyrus (DG) [2] and the subventricular zone (SVZ) of AFS cell-transplanted stroke animals compared to vehicle-infused stroke animals. A significantly higher number of double-labeled Ki67/MAP2-positive cells and a similar trend towards increased Ki67/MAP2 double-labeling were observed in the DG and SVZ of AFS cell-transplanted stroke animals, respectively, compared to vehicle-infused stroke animals. This study reports the therapeutic potential of AFS cell transplantation in stroke animals, possibly via enhancement of endogenous repair mechanisms.

CD117(+) amniotic fluid stem cells: state of the art and future perspectives

Broadly multipotent stem cells can be isolated from amniotic fluid by selection for the expression of the membrane stem cell factor receptor c-Kit, a common marker for multipotential stem cells. They have clonogenic capability and can be directed into a wide range of cell types representing the three primary embryonic lineages. Amniotic fluid stem cells maintained for over 250 population doublings retained long telomeres and a normal karyotype. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including cells of adipogenic, osteogenic, myogenic, endothelial, neuronal and hepatic lineages. AFS cells could be differentiate toward cardiomyogenic lineages, when co-cultured with neonatal cardiomyocytes, and have the potential to generate myogenic and hematopoietic lineages both in vitro and in vivo. Very recently first trimester AFS cells could be reprogrammed without any genetic manipulation opening new possibilities in the field of fetal/neonatal therapy and disease modeling. In this review we are aiming to summarize the knowledge on amniotic fluid stem cells and highlight the most promising results.

Clinical applications of prenatal and postnatal therapy using stem cells retrieved from amniotic fluid

PURPOSE OF REVIEW

To review the potential of stem cells derived from amniotic fluid and applications in prenatal and postnatal therapy.

RECENT FINDINGS

We have recently described that pluripotent stem cells can be isolated from amniotic fluid defined as amniotic fluid stem (AFS) cells by selection for expression of the membrane stem cell factor receptor c-Kit. AFS cells maintained for over 250 population doublings retained long telomeres and normal karyotype. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including adipogenic, osteogenic, myogenic, endothelial, neuronal, and hepatic lineages. Rat AFS cells have been able to improve the repair of damaged smooth muscle in cryoinjury bladders. Furthermore, AFS cells could be differentiated toward cardiomyogenic lineages, when co-cultured with neonatal cardiomyocytes and have potential to generate hematopoietic lineages both in vitro and in vivo. These cells have been applied into fetal therapy, and widely used for tissue repair in animal models. Finally, we demonstrated a feasible way to do in-utero autologous AFS transplantation in sheep.

SUMMARY

Stem cells derived from amniotic fluid are a relatively new source of cells that could have a therapeutic value in various diseases prenatally and/or postnatally.

Amniotic Fluid as a Rich Source of Mesenchymal Stromal Cells for Transplantation Therapy

Stem cells isolated from amniotic fluid are known to be able to differentiate into different cells types, thus being considered as a powerful tool for cellular therapy of different human diseases. In the last 4 years, amniotic fluid-derived stem (AFS) cells have been shown to express embryonic and adult stem cell markers. These cells can be considered an intermediate stage between embryonic stem cells and adult stem cells. AFS cells can give rise to adipogenic, osteogenic, myogenic, endothelial, neurogenic, and hepatic lineages, inclusive of all embryonic germ layers. AFS cells have a high renewal capacity and can be expanded for over 250 doublings without any detectable loss of chromosomal telomere length. Taken together, all these data provide evidence that amniotic fluid represents a new and very promising source of stem cells for research, as well as clinical applications. Certainly stem cells from amniotic fluid will be useful both for a customized cell supply for newly born children and for banking cells to be used for therapeutic cell transplantation in immunogically matched recipients. Further investigations are also warranted to fully explore the amniotic cells' potential for adult human disorders.

Effective Delivery of PEGylated siRNA-Containing Lipoplexes to Extraperitoneal Tumours following Intraperitoneal Administration

Intraperitoneal (i.p.) administration of small interfering RNA (siRNA) has, to date, shown promise in treating tumours located within the peritoneal cavity. The ability of these siRNA molecules to reach extraperitoneal tumours following i.p. administration is, however, yet to be investigated. Here, we examined the impact of PEGylation on the biodistribution of i.p. administered nucleic acids-containing lipoplexes. We showed that in contrast to non-PEGylated liposomes, PEGylated liposomes can deliver siRNA efficiently to extraperitoneal tumours following i.p. administration, resulting in a 45% reduction in tumour size when the oncogene-targeted siRNA was used. This difference was likely contributed by the decreased uptake of PEGylated lipoplexes in the first-pass organs, and, in particular, we observed a 10-fold decrease in the macrophage uptake of these particles compared to non-PEGylated counterparts. Overall, our results indicated the potential of using PEGylated liposomes to deliver siRNA for the treatment of i.p. localized cancer with coexisting extraperitoneal metastasis.

Murine amniotic fluid stem cells contribute mesenchymal but not epithelial components to reconstituted mammary ducts

Introduction

Amniotic fluid harbors cells indicative of all three germ layers, and pluripotent fetal amniotic fluid stem cells (AFSs) are considered potentially valuable for applications in cellular therapy and tissue engineering. We investigated whether it is possible to direct the cell fate of AFSs in vivo by transplantation experiments into a particular microenvironment, the mammary fat pad. This microenvironment provides the prerequisites to study stem cell function and the communication between mesenchymal and epithelial cells. On clearance of the endogenous epithelium, the ductal tree can be reconstituted by the transfer of exogenously provided mammary stem cells. Analogously, exogenously provided stem cells from other tissues can be investigated for their potential to contribute to mammary gland regeneration.

Methods

We derived pluripotent murine AFSs, measured the expression of stem cell markers, and confirmed their in vitro differentiation potential. AFSs were transplanted into cleared and non cleared fat pads of immunocompromised mice to evaluate their ability to assume particular cell fates under the instructive conditions of the fat-pad microenvironment and the hormonal stimulation during pregnancy.

Results

Transplantation of AFSs into cleared fat pads alone or in the presence of exogenous mammary epithelial cells caused their differentiation into stroma and adipocytes and replaced endogenous mesenchymal components surrounding the ducts in co-transplantation experiments. Similarly, transplantation of AFSs into fat pads that had not been previously cleared led to AFS-derived stromal cells surrounding the elongating endogenous ducts. AFSs expressed the marker protein α-SMA, but did not integrate into the myoepithelial cell layer of the ducts in virgin mice. With pregnancy, a small number of AFS-derived cells were present in acinar structures.

Conclusions

Our data demonstrate that the microenvironmental cues of the mammary fat pad cause AFSs to participate in mammary gland regeneration by providing mesenchymal components to emerging glandular structures, but do not incorporate or differentiate into ductal epithelial cells.