Amniotic Fluid and Placental Membranes
Amniotic Fluid and Placental Membranes
The highly multipotent and immunosuppressive cell populations that can be isolated from the amniotic fluid and placental tissue are a valuable source of cells that can be utilized for the treatment of disease. Here we discuss current clinical and preclinical applications of amniotic fluid and placental stem cells.
Crohn disease, also known as regional enteritis, is a chronic inflammatory condition of the gastrointestinal tract. In patients with Crohn disease, the body's own immune system attacks the gastrointestinal tract resulting in abdominal pain, diarrhea, and vomiting as well as other nongastrointestinal symptoms. Traditional treatment for Crohn disease has focused on nonspecific anti-inflammatory or immunosuppressive agents. A considerable proportion of patients develop clinically significant side effects, require surgery or become unresponsive to therapy. A growing body of evidence indicates that placental MSCs possess immunomodulatory properties and may play specific roles as immunomodulators in the maintenance of peripheral tolerance, transplantation tolerance, and autoimmunity as well as in fetal-maternal tolerance. Celgene Cellular Therapeutics has developed a placental MSC therapy for treatment-resistant Crohn disease. In a phase 1 clinical trial, 12 patients with active moderate to severe treatment-resistant Crohn disease received two infusions of placental MSCs. All patients showed signs of clinical remission of the disease. Infusion of placental MSCs appeared to be safe, and no major toxicities were observed. Celgene Cellular Therapeutics plans to continue with phase 2 studies to treat Crohn disease as well to investigate the other potential applications including a therapy for ischemic stroke.
Respiratory disease is a leading cause of morbidity and mortality. The causes of respiratory diseases differ, but the end resultant organ damage is similar—chronic inflammation, fibrosis, and scarring—leading to loss of functional lung tissue. Amnion epithelial cells show a potential to be utilized in the treatment of diseases such as cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. In animal models of lung disease, the transplantation of hAECs has been shown to reduce both inflammation and subsequent fibrosis as well as improve lung function. Administration of hAECs to mice with bleomycin-induced lung disease resulted in decreased gene expression of proinflammatory cytokines tumor necrosis factor-α, transforming growth factor-β, interferon-γ, and interleukin-6, reduced pulmonary collagen deposition, α-smooth muscle actin expression, and inflammatory cell infiltrate. Our group recently demonstrated that hAECs interact with host macrophages to exert their reparative influence, possibly by inducing macrophages into an alternatively activated phenotype. Recent studies have also induced hAECs to express lung-specific proteins including the ion channel cystic fibrosis transmembrane conductance regulator, suggesting an important application of hAECs for the treatment of patients with cystic fibrosis. These important studies highlight the potential of hAECs for clinical and bioengineering applications for patients with lung disease.
Current treatment for diabetes mellitus relies on daily multiple insulin injections or insulin pump placement, or β-cell or whole pancreas replacement. Islet transplantation is limited by the scarcity of transplant material and the requirement for lifelong immunosuppressive therapy. An alternative cell-based therapy would represent a major breakthrough in the management of this common chronic disorder. Wei and coworkers demonstrated that hAECs can be stimulated to expressed insulin and GLUT-2 mRNA, and they investigated the potential for hAEC to restore blood glucose levels in diabetic mice. In mice receiving hAECs, blood glucose decreased to normal levels posttransplantation. The body weights of hAEC-treated mice also normalized compared with mice not receiving cells. Chang et al demonstrated that placenta-derived MSCs can also be induced to secrete insulin and glucagon. They demonstrated that transplanted placenta-derived MSCs form glandlike tissues, differentiate into insulin and glucagon-positive cells, and stably restore normoglycemia in diabetic mice. These studies present a strong case for the use of gestational stem cells for the treatment of diabetes mellitus.
Cell-based therapy for bone regeneration is an emerging technology. AFSCs have the potential to be utilized to treat craniofacial bone defects and spinal or major bone injury. Preclinical studies have established that three-dimensional scaffolds containing AFSC can generate highly mineralized bone tissue 8 weeks following transplantation into mice. Micro computed tomography scanning analysis of constructs at 18 weeks postimplantation confirmed the presence of hard tissue within the AFSC-seeded constructs. The density of the tissue-engineered bone found at the sites of implantation was found to be somewhat greater than that of mouse femoral bone. Scaffolds can be designed to produce bone to generate specific craniofacial shapes or at densities to facilitate the replacement of major bones damaged by car accidents or battle injuries. Although early in development, these studies demonstrate that AFSCs are a valuable tool for future therapies for bone regeneration.
Myocardial infarction causes tissue death, and the ability to replace that lost myocardial tissue is an important goal in the field of regenerative medicine. The therapeutic potential of AFSCs for acute myocardial infarction was demonstrated by Bollini et al in a study in which Wistar rats underwent 30 minutes of ischemia by ligation of the left anterior descending coronary artery, followed by administration of AFSCs. In this model AFSCs were shown to be cardioprotective, improving myocardial cell survival and decreasing the infarct size. Other studies have identified iron oxide particle-labeled AFSCs in the mouse heart by high-resolution magnetic resonance imaging up to 28 days following injection. Lee and coworkers used AFSCs to form spherically symmetrical cell bodies, which were xenogenically transplanted in the peri-infarct area of an immune-suppressed rat via direct intramyocardial injection. The functional benefits of cell transplantation included the attenuation of the progression of heart failure, improved the global function, and increased the regional wall motion.
Regenerative therapy has the potential to cure certain hereditary forms of kidney disease and acute kidney injury, and it could eliminate the need for dialysis and/or kidney transplants in some patients with end-stage kidney disease. Perin and coworkers demonstrated that AFSCs can contribute to renal development both ex vivo and in vivo. In a mouse model of acute tubular necrosis, AFSCs integrate into the damaged tubules and provide a protective effect, ameliorating tubular necrosis in the acute injury phase. AFSC-treated animals showed decreased creatinine and blood urea nitrogen blood levels and a decrease in the number of damaged tubules. This beneficial effect with AFSCs was also correlated with significant increases in proliferative activity of tubular epithelial cells, decreased cast formation, and decreased apoptosis of tubular epithelial cells. Integrated cells expressed PAX2, NPHS1 Dolicholus Biflorus, and Peanut Agglutinin indicating AFSCs are able to commit toward renal differentiation in vivo. These studies also show evidence of potent immunomodulatory effects of AFSCs that appear to influence the local immune response to prevent or promote the resolution of tissue damage.
A major goal of regenerative medicine is to ameliorate irreversible destruction of brain tissue by utilizing stem cells to control the process of neurogenesis. The engraftment and survival of AFSCs within the rodent brain was demonstrated in the twitcher mouse model of neurologic disease. These mice are deficient in the lysosomal enzyme galactocerebrosidase and undergo extensive neurodegeneration and neurologic deterioration, initiating with the dysfunction of oligodendrocytes. AFSCs implanted directly into the lateral ventricles of the developing brain of a newborn mouse survive and integrate into the fetal mouse brain, with >70% of administered cells surviving 2 months following implantation. Rehni et al highlighted the potency of AFSCs in a mouse model of ischemic stroke. In this model, middle cerebral artery occlusion and reperfusion produces ischemia and reperfusion-induced cerebral injury and induces behavioral deficits in mice. Behavioral changes included markedly impaired memory, motor coordination, sensorimotor ability, and somatosensory functions. Intracerebroventricular administration of AFSCs had a significant neuroprotective effect, reversing the focal cerebral ischemia-reperfusion induced behavioral deficits observed in untreated mice. These studies suggest that AFSCs may have important clinical applications for the treatment of degenerative or behavioral brain disorders, paving the way for potential treatments for disease such as stroke, Parkinson disease, Alzheimer disease, and spinal injuries.
Ditadi and coworkers demonstrated that AFSCs display multilineage hematopoietic differentiation potential, generating erythroid, myeloid, and lymphoid cells in vitro, suggesting that AFSCs may be an important source of cells to regenerate the hematopoietic system. This study demonstrated that 4 months following AFSC injection into immunodeficient RAG1 C57BL/6 (Ly5.1) mice, AFSC-derived macrophages, NK, B, and T cells (both CD4+ and CD8+ CD3 + ) were found in transplanted animals. Secondary transplantation was partially successful, suggesting the presence of a small number of hematopoietic progenitor cells within the multipotent AFSC population. These transplantation experiments indicated that AFSCs possess long-term in vivo hematopoietic repopulating capacity and potential therapeutic applications for the treatment of blood and immune disorders.
Amniotic Fluid and Placenta for Cell Therapy
The highly multipotent and immunosuppressive cell populations that can be isolated from the amniotic fluid and placental tissue are a valuable source of cells that can be utilized for the treatment of disease. Here we discuss current clinical and preclinical applications of amniotic fluid and placental stem cells.
Therapy for Crohn Disease
Crohn disease, also known as regional enteritis, is a chronic inflammatory condition of the gastrointestinal tract. In patients with Crohn disease, the body's own immune system attacks the gastrointestinal tract resulting in abdominal pain, diarrhea, and vomiting as well as other nongastrointestinal symptoms. Traditional treatment for Crohn disease has focused on nonspecific anti-inflammatory or immunosuppressive agents. A considerable proportion of patients develop clinically significant side effects, require surgery or become unresponsive to therapy. A growing body of evidence indicates that placental MSCs possess immunomodulatory properties and may play specific roles as immunomodulators in the maintenance of peripheral tolerance, transplantation tolerance, and autoimmunity as well as in fetal-maternal tolerance. Celgene Cellular Therapeutics has developed a placental MSC therapy for treatment-resistant Crohn disease. In a phase 1 clinical trial, 12 patients with active moderate to severe treatment-resistant Crohn disease received two infusions of placental MSCs. All patients showed signs of clinical remission of the disease. Infusion of placental MSCs appeared to be safe, and no major toxicities were observed. Celgene Cellular Therapeutics plans to continue with phase 2 studies to treat Crohn disease as well to investigate the other potential applications including a therapy for ischemic stroke.
Lung Regeneration
Respiratory disease is a leading cause of morbidity and mortality. The causes of respiratory diseases differ, but the end resultant organ damage is similar—chronic inflammation, fibrosis, and scarring—leading to loss of functional lung tissue. Amnion epithelial cells show a potential to be utilized in the treatment of diseases such as cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. In animal models of lung disease, the transplantation of hAECs has been shown to reduce both inflammation and subsequent fibrosis as well as improve lung function. Administration of hAECs to mice with bleomycin-induced lung disease resulted in decreased gene expression of proinflammatory cytokines tumor necrosis factor-α, transforming growth factor-β, interferon-γ, and interleukin-6, reduced pulmonary collagen deposition, α-smooth muscle actin expression, and inflammatory cell infiltrate. Our group recently demonstrated that hAECs interact with host macrophages to exert their reparative influence, possibly by inducing macrophages into an alternatively activated phenotype. Recent studies have also induced hAECs to express lung-specific proteins including the ion channel cystic fibrosis transmembrane conductance regulator, suggesting an important application of hAECs for the treatment of patients with cystic fibrosis. These important studies highlight the potential of hAECs for clinical and bioengineering applications for patients with lung disease.
Pancreatic Tissue Insulin Production
Current treatment for diabetes mellitus relies on daily multiple insulin injections or insulin pump placement, or β-cell or whole pancreas replacement. Islet transplantation is limited by the scarcity of transplant material and the requirement for lifelong immunosuppressive therapy. An alternative cell-based therapy would represent a major breakthrough in the management of this common chronic disorder. Wei and coworkers demonstrated that hAECs can be stimulated to expressed insulin and GLUT-2 mRNA, and they investigated the potential for hAEC to restore blood glucose levels in diabetic mice. In mice receiving hAECs, blood glucose decreased to normal levels posttransplantation. The body weights of hAEC-treated mice also normalized compared with mice not receiving cells. Chang et al demonstrated that placenta-derived MSCs can also be induced to secrete insulin and glucagon. They demonstrated that transplanted placenta-derived MSCs form glandlike tissues, differentiate into insulin and glucagon-positive cells, and stably restore normoglycemia in diabetic mice. These studies present a strong case for the use of gestational stem cells for the treatment of diabetes mellitus.
Bone Regeneration
Cell-based therapy for bone regeneration is an emerging technology. AFSCs have the potential to be utilized to treat craniofacial bone defects and spinal or major bone injury. Preclinical studies have established that three-dimensional scaffolds containing AFSC can generate highly mineralized bone tissue 8 weeks following transplantation into mice. Micro computed tomography scanning analysis of constructs at 18 weeks postimplantation confirmed the presence of hard tissue within the AFSC-seeded constructs. The density of the tissue-engineered bone found at the sites of implantation was found to be somewhat greater than that of mouse femoral bone. Scaffolds can be designed to produce bone to generate specific craniofacial shapes or at densities to facilitate the replacement of major bones damaged by car accidents or battle injuries. Although early in development, these studies demonstrate that AFSCs are a valuable tool for future therapies for bone regeneration.
Myocardial Infarction
Myocardial infarction causes tissue death, and the ability to replace that lost myocardial tissue is an important goal in the field of regenerative medicine. The therapeutic potential of AFSCs for acute myocardial infarction was demonstrated by Bollini et al in a study in which Wistar rats underwent 30 minutes of ischemia by ligation of the left anterior descending coronary artery, followed by administration of AFSCs. In this model AFSCs were shown to be cardioprotective, improving myocardial cell survival and decreasing the infarct size. Other studies have identified iron oxide particle-labeled AFSCs in the mouse heart by high-resolution magnetic resonance imaging up to 28 days following injection. Lee and coworkers used AFSCs to form spherically symmetrical cell bodies, which were xenogenically transplanted in the peri-infarct area of an immune-suppressed rat via direct intramyocardial injection. The functional benefits of cell transplantation included the attenuation of the progression of heart failure, improved the global function, and increased the regional wall motion.
Renal Disease
Regenerative therapy has the potential to cure certain hereditary forms of kidney disease and acute kidney injury, and it could eliminate the need for dialysis and/or kidney transplants in some patients with end-stage kidney disease. Perin and coworkers demonstrated that AFSCs can contribute to renal development both ex vivo and in vivo. In a mouse model of acute tubular necrosis, AFSCs integrate into the damaged tubules and provide a protective effect, ameliorating tubular necrosis in the acute injury phase. AFSC-treated animals showed decreased creatinine and blood urea nitrogen blood levels and a decrease in the number of damaged tubules. This beneficial effect with AFSCs was also correlated with significant increases in proliferative activity of tubular epithelial cells, decreased cast formation, and decreased apoptosis of tubular epithelial cells. Integrated cells expressed PAX2, NPHS1 Dolicholus Biflorus, and Peanut Agglutinin indicating AFSCs are able to commit toward renal differentiation in vivo. These studies also show evidence of potent immunomodulatory effects of AFSCs that appear to influence the local immune response to prevent or promote the resolution of tissue damage.
Neural Regeneration
A major goal of regenerative medicine is to ameliorate irreversible destruction of brain tissue by utilizing stem cells to control the process of neurogenesis. The engraftment and survival of AFSCs within the rodent brain was demonstrated in the twitcher mouse model of neurologic disease. These mice are deficient in the lysosomal enzyme galactocerebrosidase and undergo extensive neurodegeneration and neurologic deterioration, initiating with the dysfunction of oligodendrocytes. AFSCs implanted directly into the lateral ventricles of the developing brain of a newborn mouse survive and integrate into the fetal mouse brain, with >70% of administered cells surviving 2 months following implantation. Rehni et al highlighted the potency of AFSCs in a mouse model of ischemic stroke. In this model, middle cerebral artery occlusion and reperfusion produces ischemia and reperfusion-induced cerebral injury and induces behavioral deficits in mice. Behavioral changes included markedly impaired memory, motor coordination, sensorimotor ability, and somatosensory functions. Intracerebroventricular administration of AFSCs had a significant neuroprotective effect, reversing the focal cerebral ischemia-reperfusion induced behavioral deficits observed in untreated mice. These studies suggest that AFSCs may have important clinical applications for the treatment of degenerative or behavioral brain disorders, paving the way for potential treatments for disease such as stroke, Parkinson disease, Alzheimer disease, and spinal injuries.
Blood and Immune System Regeneration
Ditadi and coworkers demonstrated that AFSCs display multilineage hematopoietic differentiation potential, generating erythroid, myeloid, and lymphoid cells in vitro, suggesting that AFSCs may be an important source of cells to regenerate the hematopoietic system. This study demonstrated that 4 months following AFSC injection into immunodeficient RAG1 C57BL/6 (Ly5.1) mice, AFSC-derived macrophages, NK, B, and T cells (both CD4+ and CD8+ CD3 + ) were found in transplanted animals. Secondary transplantation was partially successful, suggesting the presence of a small number of hematopoietic progenitor cells within the multipotent AFSC population. These transplantation experiments indicated that AFSCs possess long-term in vivo hematopoietic repopulating capacity and potential therapeutic applications for the treatment of blood and immune disorders.
