Cell necrosis, intrinsic apoptosis and senescence contribute to the progression of exencephaly to anencephaly in a mice model of congenital chranioschisis.

Exencephaly/anencephaly is one of the leading causes of neonatal mortality and the most extreme open neural tube defect with no current treatments and limited mechanistic understanding. We hypothesized that exencephaly leads to a local neurodegenerative process in the brain exposed to the amniotic fluid as well as diffuse degeneration in other encephalic areas and the spinal cord. To evaluate the consequences of in utero neural tissue exposure, brain and spinal cord samples from E17 exencephalic murine fetuses (maternal intraperitoneal administration of valproic acid at E8) were analyzed and compared to controls and saline-injected shams (n = 11/group). Expression of apoptosis and senescence genes (p53, p21, p16, Rbl2, Casp3, Casp9) was determined by qRT-PCR and protein expression analyzed by western blot. Apoptosis was measured by TUNEL assay and PI/AV flow cytometry. Valproic acid at E8 induced exencephaly in 22% of fetuses. At E17 the fetuses exhibited the characteristic absence of cranial bones. The brain structures from exencephalic fetuses demonstrated a loss of layers in cortical regions and a complete loss of structural organization in the olfactory bulb, hippocampus, dental gyrus and septal cortex. E17 fetuses had reduced expression of NeuN, GFAP and Oligodendrocytes in the brain with primed microglia. Intrinsic apoptotic activation (p53, Caspase9 and 3) was upregulated and active Caspase3 localized to the layer of brain exposed to the amniotic fluid. Senescence via p21-Rbl2 was increased in the brain and in the spinal cord at the lamina I-II of the somatosensory dorsal horn. The current study characterizes CNS alterations in murine exencephaly and demonstrates that degeneration due to intrinsic apoptosis and senescence occurs in the directly exposed brain but also remotely in the spinal cord.

Isolation, characterization, and differentiation of multipotent neural progenitor cells from human cerebrospinal fluid in fetal cystic myelomeningocele.

Despite benefits of prenatal in utero repair of myelomeningocele, a severe type of spina bifida aperta, many of these patients will still suffer mild to severe impairment. One potential source of stem cells for new regenerative medicine-based therapeutic approaches for spinal cord injury repair is neural progenitor cells (NPCs) in cerebrospinal fluid (CSF). To this aim, we extracted CSF from the cyst surrounding the exposed neural placode during the surgical repair of myelomeningocele in 6 fetuses (20 to 26weeks of gestation). In primary cultured CSF-derived cells, neurogenic properties were confirmed by in vitro differentiation into various neural lineage cell types, and NPC markers expression (TBR2, CD15, SOX2) were detected by immunofluorescence and RT-PCR analysis. Differentiation into three neural lineages was corroborated by arbitrary differentiation (depletion of growths factors) or explicit differentiation as neuronal, astrocyte, or oligodendrocyte cell types using specific induction mediums. Differentiated cells showed the specific expression of neural differentiation markers (ßIII-tubulin, GFAP, CNPase, oligo-O1). In myelomeningocele patients, CSF-derived cells could become a potential source of NPCs with neurogenic capacity. Our findings support the development of innovative stem-cell-based therapeutics by autologous transplantation of CSF-derived NPCs in damaged spinal cords, such as myelomeningocele, thus promoting neural tissue regeneration in fetuses.

The role of subscapularis muscle denervation in the pathogenesis of shoulder internal rotation contracture after neonatal brachial plexus palsy: a study in a rat model.

We assessed the role of subscapularis muscle denervation in the development of shoulder internal rotation contracture in neonatal brachial plexus injury. Seventeen newborn rats underwent selective denervation of the subscapular muscle. The rats were evaluated at weekly intervals to measure passive shoulder external rotation. After 4 weeks, the animals were euthanized. The subscapularis thickness was measured using 7.2T MRI axial images. The subscapularis muscle was then studied grossly, and its mass was registered. The fiber area and the area of fibrosis were measured using collagen-I inmunostained muscle sections. Significant progressive decrease in passive shoulder external rotation was noted with a mean loss of 58° at four weeks. A significant decrease in thickness and mass of the subscapularis muscles in the involved shoulders was also found with a mean loss of 69%. Subscapularis muscle fiber size decreased significantly, while the area of fibrosis remained unchanged. Our study shows that subscapularis denervation, per se, could explain shoulder contracture after neonatal brachial plexus injury, though its relevance compared to other pathogenic factors needs further investigation.