Immunosuppressive potential of human amnion epithelial cells in the treatment of experimental autoimmune encephalomyelitis

BACKGROUND: Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS). In recent years, it has been found that cells such as human amnion epithelial cells (hAECs) have the ability to modulate immune responses in vitro and in vivo and can differentiate into multiple cell lineages. Accordingly, we investigated the immunoregulatory effects of hAECs as a potential therapy in an MS-like disease, EAE (experimental autoimmune encephalomyelitis), in mice. METHODS: Using flow cytometry, the phenotypic profile of hAECs from different donors was assessed. The immunomodulatory properties of hAECs were examined in vitro using antigen-specific and one-way mixed lymphocyte proliferation assays. The therapeutic efficacy of hAECs was examined using a relapsing-remitting model of EAE in NOD/Lt mice. T cell responsiveness, cytokine secretion, T regulatory, and T helper cell phenotype were determined in the peripheral lymphoid organs and CNS of these animals. RESULTS: In vitro, hAECs suppressed both specific and non-specific T cell proliferation, decreased pro-inflammatory cytokine production, and inhibited the activation of stimulated T cells. Furthermore, T cells retained their naïve phenotype when co-cultured with hAECs. In vivo studies revealed that hAECs not only suppressed the development of EAE but also prevented disease relapse in these mice. T cell responses and production of the pro-inflammatory cytokine interleukin (IL)-17A were reduced in hAEC-treated mice, and this was coupled with a significant increase in the number of peripheral T regulatory cells and naïve CD4+ T cells. Furthermore, increased proportions of Th2 cells in the peripheral lymphoid organs and within the CNS were observed. CONCLUSION: The therapeutic effect of hAECs is in part mediated by inducing an anti-inflammatory response within the CNS, demonstrating that hAECs hold promise for the treatment of autoimmune diseases like MS

Immune stress in late pregnant rats decreases length of gestation and fecundity, and alters later cognitive and affective behaviour of surviving pre-adolescent offspring

Immune challenge during pregnancy is associated with preterm birth and poor perinatal development. The mechanisms of these effects are not known. 5α-Pregnan-3α-ol-20-one (3α,5α-THP), the neuroactive metabolite of progesterone, is critical for neurodevelopment and stress responses, and can influence cognition and affective behaviours. To develop an immune challenge model of preterm birth, pregnant Long–Evans rat dams were administered lipopolysaccharide [LPS; 30 μg/kg/ml, intraperitoneal (IP)], interleukin-1β (IL-1β; 1 μg/rat, IP) or vehicle (0.9% saline, IP) daily on gestational days 17–21. Compared to control treatment, prenatal LPS or IL-1β reduced gestational length and the number of viable pups born. At 28–30 days of age, male and female offspring of mothers exposed to prenatal IL-1β had reduced cognitive performance in the object recognition task compared to controls. In females, but not males, prenatal IL-1β reduced anxiety-like behaviour, indicated by entries to the centre of an open field. In the hippocampus, progesterone turnover to its 5α-reduced metabolites was lower in prenatally exposed IL-1β female, but not in male offspring. IL-1β-exposed males and females had reduced oestradiol content in hippocampus, medial prefrontal cortex and diencephalon compared to controls. Thus, immune stress during late pregnancy reduced gestational length and negatively impacted birth outcomes, hippocampal function and central neurosteroid formation in the offspring

Role of neurosteroids in regulating cell death and proliferation in the late gestation fetal brain

The neurosteroid allopregnanolone (AP) is a GABAergic agonist that suppresses central nervous system (CNS) activity in the adult brain, and by reducing excitotoxicity is considered to be neuroprotective. A role for neurosteroids in the developing brain, particularly in late gestation, is still debated. The aim of this study was to investigate effects on proliferation and cell death in the brain of late gestation fetal sheep after inhibition of AP synthesis using finasteride, a 5α-reductase type 2 (5α-R2) inhibitor. Catheters were implanted in fetal sheep at 125 days of gestation. At 3–4 days postsurgery, fetuses received infusions of either finasteride (20 mg/kg/h; n=5), the AP analogue alfaxalone (5 mg/kg/h; n=5), or finasteride and alfaxalone together (n=5). Brains were obtained at 24 h after infusion to determine cell death (apoptotic or necrotic) and cell proliferation in the hippocampus and cerebellum, areas known to be susceptible to excitotoxic damage. Finasteride treatment significantly increased apoptosis (activated caspase-3 expression) in hippocampal CA3 and CA1, and cerebellar molecular and granular layers, an effect abolished by co-infusion of alfaxalone and finasteride. Double-label immunohistochemistry showed that both neurons and astrocytes were caspase-3 positive. Finasteride treatment also increased the number of dead (pyknotic) cells in the hippocampus and cerebellum (Purkinje cells), but not when finasteride+alfaxalone was infused. Cell proliferation (Ki-67-immunoreactivity) increased after finasteride treatment; double-labeling showed the majority of Ki-67-positive cells were astrocytes. Thus, steroids such as AP appear to influence the constitutive rate of apoptosis and proliferation in the hippocampus and cerebellum of the fetal brain, and suggest an important role for neurosteroids in the development of the brain

Ganaxolone: A new treatment for neonatal seizures

Neonatal seizures are amongst the most common neurologic conditions managed by a neonatal care service. Seizures can exacerbate existing brain injury, induce "de novo" injury, and are associated with neurodevelopmental disabilities in post-neonatal life. In this mini-review, we present evidence in support of the use of ganaxolone, a GABAA agonist neurosteroid, as a novel neonatal therapy. We discuss evidence that ganaxolone can provide both seizure control and neuroprotection with a high safety profile when administered early following birth-related hypoxia, and show evidence that it is likely to prevent or reduce the incidence of the enduring disabilities associated with preterm birth, cerebral palsy, and epilepsy. We suggest that ganaxolone is an ideal anti-seizure treatment because it can be safely used prospectively, with minimal or no adverse effects on the neonatal brain

Mechanisms of melatonin-induced protection in the brain of late gestation fetal sheep in response to hypoxia

Melatonin has diverse physiological actions in addition to its well-recognized maintenance roles in circadian and seasonal timing. In particular, melatonin may have a direct protective action on the developing fetal brain. We examined the cellular processes by which melatonin provides protection following an acute late gestation hypoxic insult. 15 fetal sheep at 126 days' gestation were instrumented with a brachial artery catheter and a silastic cuff around the umbilical cord. At ∼130 days' gestation, the cuff was inflated for 10 min in 10 fetuses, causing complete umbilical cord occlusion (UCO). 5 UCO fetuses received intravenous melatonin maternally for 2 h, before and after UCO (UCO + melatonin). The remaining 5 fetuses had no UCO performed (sham-operated controls). At 48 h after UCO, the fetal brain was collected from each animal. Compared to controls, UCO caused significant hypoxia, hypercapnia and acidosis in UCO and UCO + melatonin fetuses. In the UCO-alone animals there were significant increases in pyknotic cell death, in the hippocampus (>7-fold) and the cerebellum (3-fold). Maternal melatonin administration ameliorated cellular pyknosis in UCO fetuses. UCO was also associated with astrogliosis, increased albumin uptake, activated microglia and lipid peroxidation. Melatonin prevented these effects. There were no significant differences in the number of brain macrophages or microglia between any of the groups. Following acute severe hypoxia in the late gestation fetus, melatonin reduces neuronal lipid peroxidation and prevents loss of blood-brain barrier integrity and astrogliosis. These are likely key mechanisms underlying the neuroprotective actions of melatonin in the fetal brain

The effects of betamethasone on allopregnanolone concentrations and brain development in preterm fetal sheep

The risk of preterm delivery often means that the fetus will be exposed to exogenous synthetic glucocorticoids to accelerate fetal lung maturation, but effects on other organs, particularly the brain, are not understood. The neurosteroid allopregnanolone (AP) is a GABAA receptor agonist that influences fetal brain development and has neuroprotective properties. In this study we determined the impact of maternal glucocorticoid (betamethasone) administration on brain development and AP synthesis in preterm fetal sheep. Pregnant ewes underwent surgery at 105 days gestation for implantation of fetal catheters. Ewes received either betamethasone (BM; 11.4 mg; n = 10) or vehicle (saline; n = 5) by i.m injection on days five (BM1) and six (BM2) following surgery. Five fetuses of the BM treated ewes received an infusion of alfaxalone (20 mg) over 48 h commencing 30 min prior to BM1. All animals were euthanased on day 7, and the fetal brains collected to determine AP concentrations and histopathology. BM significantly reduced AP levels in the fetal brain and placental cotyledons, and also in fetal plasma without altering progesterone concentrations. There was a significant decrease in the number of myelinating cells in subcortical white matter, but no change to total oligodendrocyte number. Co-administration of the AP analogue analog alfaxalone with BM prevented this change in MBP expression. BM, given at a dose clinically prescribed to accelerate lung maturation, adversely affects neurosteroid levels in the preterm fetal brain, and affects the maturational profile of white matter development; these effects were mitigated by the co-administration of alfaxolone