Amniotic fluid stem cells as a novel strategy for the treatment of fetal and neonatal neurological diseases.

Even in the context of modern medicine, infants with fetal and neonatal neurological diseases such as cerebral palsy and myelomeningocele suffer serious long-lasting impairment due to the irreversible neuronal damage. The promotion of neurologically intact survival in patients with perinatal intractable neurological diseases requires the development of novel strategies. One promising strategy involves the use of human amniotic fluid stem cells (hAFSCs), which have attracted much attention in recent years and are known to exert anti-inflammatory and neuroprotective effects. In recent years, the therapeutic effects of hAFSCs on fetal-neonatal neurological diseases have become evident as per intense research efforts by our group and others. Specifically, hAFSCs administered into the nasal cavity migrated to the brain and controlled local inflammation in a rodent model of neonatal hypoxic-ischemic encephalopathy. In contrast, hAFSCs administered intraperitoneally did not migrate to the brain; they rather formed spheroids in the abdominal cavity, resulting in the suppression of systemic inflammation (including in the brain) via the secretion of anti-inflammatory cytokines in concert with peritoneal macrophages in a rodent model of periventricular leukomalacia. Moreover, studies in a rat model of myelomeningocele suggested that hAFSCs administered in utero secreted hepatocyte growth factor and protected the exposed spinal cord during pregnancy. Importantly, autologous hAFSCs, whose use for fetal-neonatal treatment does not raise ethical issues, can be collected during pregnancy and prepared in sufficient numbers for therapeutic use. This article outlines the results of preclinical research on fetal stem cell therapy, mainly involving hAFSCs, in the context of perinatal neurological diseases.

Cell sheets using human amniotic fluid stem cells reduce tissue fibrosis in murine full-thickness skin wounds.

The use of mesenchymal stem cell sheets is a promising strategy for skin regeneration. The injection of dissociated human amniotic fluid stem cells (hAFSCs) was recently found to accelerate cutaneous wound healing with reduced fibrotic scarring, similar to fetal wound healing. However, the use of hAFSCs in applications of cell sheet technology remains limited. The aim of this study was to determine the in vivo efficacy of in vitro-cultured hAFSC sheets in wound healing. The cell sheets were characterized by immunohistochemistry and RT-qPCR and grafted onto full-thickness wounds in BALB/c mice. The wound size was measured, and re-epithelialization, granulation tissue area, and collagen content of the regenerated wound were analyzed histologically. Although the hAFSC sheet contained abundant extracellular matrix molecules and expressed high levels of anti-fibrotic mediators, its grafting did not affect wound closure or the size of the granulation tissue area. In contrast, the organization of type I collagen bundles in the regenerated wound was markedly reduced, while the levels of type III collagen were increased after implantation of the hAFSC sheet. These results suggest that hAFSC sheets can exert anti-fibrotic properties without delaying wound closure.

Prophylactic therapy with human amniotic fluid stem cells improved survival in a rat model of lipopolysaccharide-induced neonatal sepsis through immunomodulation via aggregates with peritoneal macrophages.

BACKGROUND: Despite recent advances in neonatal care, sepsis remains a leading cause of mortality in neonates. Mesenchymal stem cells derived from various tissues, such as bone marrow, umbilical cord, and adipose tissue, have beneficial effects on adult sepsis. Although human amniotic fluid stem cells (hAFSCs) have mesenchymal stem cell properties, the efficacy of hAFSCs on neonatal sepsis is yet to be elucidated. This study aimed to investigate the therapeutic potential of hAFSCs on neonatal sepsis using a rat model of lipopolysaccharide (LPS)-induced sepsis. METHODS: hAFSCs were isolated as CD117-positive cells from human amniotic fluid. Three-day-old rat pups were intraperitoneally treated with LPS to mimic neonatal sepsis. hAFSCs were administered either 3 h before or at 0, 3, or 24 h after LPS exposure. Serum inflammatory cytokine levels, gene expression profiles from spleens, and multiple organ damage were analyzed. hAFSC localization was determined in vivo. In vitro LPS stimulation tests were performed using neonatal rat peritoneal macrophages co-cultured with hAFSCs in a cell-cell contact-dependent/independent manner. Immunoregulation in the spleen was determined using a DNA microarray analysis. RESULTS: Prophylactic therapy with hAFSCs improved survival in the LPS-treated rats while the hAFSCs transplantation after LPS exposure did not elicit a therapeutic response. Therefore, hAFSC pretreatment was used for all subsequent studies. Inflammatory cytokine levels were elevated after LPS injection, which was attenuated by hAFSC pretreatment. Subsequently, inflammation-induced damages in the brain, lungs, and liver were ameliorated. hAFSCs aggregated with peritoneal macrophages and/or transiently accumulated in the liver, mesentery, and peritoneum. Paracrine factors released by hAFSCs induced M1-M2 macrophage polarization in a cell-cell contact-independent manner. Direct contact between hAFSCs and peritoneal macrophages further enhanced the polarization. Microarray analysis of the spleen showed that hAFSC pretreatment reduced the expression of genes involved in apoptosis and inflammation and subsequently suppressed toll-like receptor 4 signaling pathways. CONCLUSIONS: Prophylactic therapy with hAFSCs improved survival in a rat model of LPS-induced neonatal sepsis. These effects might be mediated by a phenotypic switch from M1 to M2 in peritoneal macrophages, triggered by hAFSCs in a cell-cell contact-dependent/independent manner and the subsequent immunomodulation of the spleen.

In Utero Amniotic Fluid Stem Cell Therapy Protects Against Myelomeningocele via Spinal Cord Coverage and Hepatocyte Growth Factor Secretion.

Despite the poor prognosis associated with myelomeningocele (MMC), the options for prenatal treatments are still limited. Recently, fetal cellular therapy has become a new option for treating birth defects, although the therapeutic effects and mechanisms associated with such treatments remain unclear. The use of human amniotic fluid stem cells (hAFSCs) is ideal with respect to immunoreactivity and cell propagation. The prenatal diagnosis of MMC during early stages of pregnancy could allow for the ex vivo proliferation and modulation of autologous hAFSCs for use in utero stem cell therapy. Therefore, we investigated the therapeutic effects and mechanisms of hAFSCs-based treatment for fetal MMC. hAFSCs were isolated as CD117-positive cells from the amniotic fluid of 15- to 17-week pregnant women who underwent amniocentesis for prenatal diagnosis and consented to this study. Rat dams were exposed to retinoic acid to induce fetal MMC and were subsequently injected with hAFSCs in each amniotic cavity. We measured the exposed area of the spinal cord and hepatocyte growth factor (HGF) levels at the lesion. The exposed spinal area of the hAFSC-treated group was significantly smaller than that of the control group. Immunohistochemical analysis demonstrated a reduction in neuronal damage such as neurodegeneration and astrogliosis in the hAFSC-treated group. Additionally, in lesions of the hAFSC-treated group, HGF expression was upregulated and HGF-positive hAFSCs were identified, suggesting that these cells migrated to the lesion and secreted HGF to suppress neuronal damage and induce neurogenesis. Therefore, in utero hAFSC therapy could become a novel strategy for fetal MMC. Stem Cells Translational Medicine 2019;8:1170-1179.

The neurorestorative effect of human amniotic fluid stem cells on the chronic phase of neonatal hypoxic-ischemic encephalopathy in mice.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) remains a major cause of cerebral palsy. Increasing evidence has suggested that mesenchymal stem cells have a favorable effect on HIE. However, the efficacy of human amniotic fluid stem cells (hAFS) for HIE, especially in the chronic phase, remains unclear. The aim of this study was to determine the neurorestorative effect of hAFS on the chronic phase of HIE. METHODS: hAFS were isolated from AF cells as CD117-positive cells. HI was induced in 9-day-old mice. Animals intranasally received hAFS or phosphate-buffered saline at 10 days post HI and were harvested for histological analysis after functional tests at 21 days post HI. We also implanted PKH26-positive hAFS to assess their migration to the brain. Finally, we determined gene expressions of trophic factors in hAFS co-cultured with HI brain extract. RESULTS: hAFS improved sensorimotor deficits in HIE by gray and white matter restoration and neuroinflammation reduction followed by migration to the lesion. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal cell-derived factor-1 (SDF-1) gene expressions in hAFS were elevated when exposed to HI-induced brain extract. CONCLUSION: hAFS induced functional recovery by exerting neurorestorative effects in HIE mice, suggesting that intranasal administration of hAFS could be a novel treatment for HIE, especially in the chronic phase.

Human amniotic fluid stem cells have a unique potential to accelerate cutaneous wound healing with reduced fibrotic scarring like a fetus.

Adult wound healing can result in fibrotic scarring (FS) characterized by excess expression of myofibroblasts and increased type I/type III collagen expression. In contrast, fetal wound healing results in complete regeneration without FS, and the mechanism remains unclear. Amniotic fluid cells could contribute to scar-free wound healing, but the effects of human amniotic fluid cells are not well characterized. Here, we determined the effect of human amniotic fluid stem cells (hAFS) on FS during wound healing. Human amniotic fluid was obtained by amniocentesis at 15-17 weeks of gestation. CD117-positive cells were isolated and defined as hAFS. hAFS (1 × 106) suspended in PBS or cell-free PBS were injected around wounds created in the dorsal region of BALB/c mice. Wound size was macroscopically measured, and re-epithelialization in the epidermis, granulation tissue area in the dermis and collagen contents in the regenerated wound were histologically analyzed. The ability of hAFS to engraft in the wound was assessed by tracking hAFS labeled with PKH-26. hAFS fulfilled the minimal criteria for mesenchymal stem cells. hAFS injection into the wound accelerated wound closure via enhancement of re-epithelialization with less FS. The process was characterized by lower numbers of myofibroblasts and higher expression of type III collagen. Finally, transplanted hAFS were clearly observed in the dermis until day 7 implying that hAFS worked in a paracrine manner. hAFS can function in a paracrine manner to accelerate cutaneous wound healing, producing less FS, a process resembling fetal wound healing.

Human Amniotic Fluid Stem Cells: Therapeutic Potential for Perinatal Patients with Intractable Neurological Disease.

Mesenchymal stem cells (MSCs) have generated great interest in the fields of regenerative medicine and immunotherapy because of their unique biological properties. Among MSCs, amniotic fluid stem cells (AFS) have a number of characteristics that make them attractive candidates for tissue engineering and cell replacement strategies, particularly for perinatal medicine. If various neonatal conditions, including birth asphyxia, preterm birth, and congenital abnormalities, which result in long-lasting severe impairments, could be predicted during pregnancy, it would allow collection of small samples of amniotic fluid cells by amniocentesis. In vitro culture of these autologous AFS during pregnancy would make them available for use soon after birth. Hypoxic-ischemic encephalopathy (HIE) and myelomeningocele (MMC) are neonatal conditions that cause permanent neurological disability, for which the treatment options are extremely limited. Experiments using animal models of HIE and MMC and human clinical trials have demonstrated that MSCs, including AFS, have beneficial effects on the central nervous system through paracrine influences, indicating that autologous AFS treatment may be applicable for intractable neurological diseases, including HIE and MMC, during the perinatal period. In this review, we focus on recent research related to the therapeutic potential of AFS for perinatal neurological diseases such as HIE and MMC.

Time-dependent changes in insulin requirement for maternal glycemic control during antenatal corticosteroid therapy in women with gestational diabetes: a retrospective study.

Though recommended for pregnant women at risk of preterm birth to improve perinatal outcomes, antenatal corticosteroid (ACS) treatment can cause maternal hyperglycemia, especially in cases of glucose intolerance. A standardized protocol for preventing hyperglycemia during ACS treatment remains to be established. We herein retrospectively investigated the time-dependent changes in insulin dose required for maternal glycemic control during ACS treatment in gestational diabetes (GDM). Twelve singleton pregnant women with GDM who received 12 mg of betamethasone intramuscularly twice 24 hours apart were included in this analysis. Of those, eight also received ritodrine hydrochloride for preterm labor. The blood glucose levels were maintained at 70-120 mg/dL with continuous intravenous infusion of insulin and nothing by mouth for 48 hours after the first betamethasone administration. After the first dose of betamethasone, the insulin dosage needed for glycemic control gradually increased and reached a maximum (6.6 ± 5.8 units/hr) at 10 hours, then, decreased to 4.1 ± 1.5 units/hr at 24 hours. Similar changes in the insulin requirement were found after the second betamethasone dose (the maximum insulin dosage: 5.5 ± 1.6 units/hr at 9 hours following the second administration). Women treated with ritodrine hydrochloride needed more insulin, than those without ritodrine hydrochloride treatment (130.8 ± 15.0 vs. 76.8 ± 15.2 units/day, respectively, p < 0.05). Our data indicated that the requirement for insulin is highest 9-10 hours after each dose of betamethasone. When GDM is treated with ACS, levels of blood glucose should be carefully monitored, especially in patients treated with ritodrine hydrochloride.

Clinical impact of women with gestational diabetes mellitus by the new consensus criteria: two year experience in a single institution in Japan.

There is a paucity of information on perinatal data regarding gestational diabetes mellitus (GDM) by the new criteria from a real experience because the number of health care associations implementing the new criteria is still limited. The aim of this study is to investigate perinatal features of the new criteria-defined GDM. We reviewed a total of 995 women with singleton pregnancy that underwent GDM screening followed by a diagnostic oral glucose tolerance test (OGTT). All women found to have GDM underwent self-monitoring of blood glucose measurements as well as dietary management. Insulin treatment was initiated when dietary treatment did not achieve the glycemic goal. Of the 995 women, 141 had GDM (14.2%): 104 with one, 27 with two, and 10 with three abnormal OGTT values. Women with two or three abnormal OGTT values (2/3-AV) needed insulin treatment more frequently than those with one abnormal OGTT value (1-AV) (70.3% vs 23.1%, P < 0.0001). After adjustment for age, pregravid overweight, gestational weeks at diagnosis, a first-degree family history of diabetes was correlated with the implementation of insulin treatment in women with 1-AV (adjusted odds ratio 3.9; 95% Confidence Interval 1.7-9.2; P = 0.001). When compared perinatal outcomes between women with normal glucose tolerance and GDM, fetal growth and the occurrence of pregnancy-induced hypertension were comparable between the two groups. Our data suggest that the IADPSG-defined GDM with 1-AV show less severe glucose intolerance, but might be at risk of insulin requirement when a first-degree family history of diabetes exists.