[To act or not to act? Developments in prenatal and postnatal care for children with spina bifida aperta]

To act or not to act? Developments in prenatal and postnatal care for children with spina bifida aperta Until the middle of the twentieth century, newborns with spina bifida aperta had low chances of survival. Advances in the treatment of hydrocephalus, among other conditions, led to increased chances of survival during the 1960s. This also revealed the downsides of the treatment of spina bifida patients since some considered the quality of life of a number of these patients to be unacceptable. But withholding treatment also had negative consequences, leading to an ethical deadlock. Over the past thirty years - besides postnatal closure of the neural tube defect - more emphasis has been put on selective pregnancy termination and sporadic active termination of life in newborns with very severe forms of spina bifida. At the same time, new treatment strategies, such as foetal surgery, are being developed. With this historical overview, we illustrate the way in which technological developments and ethical dilemmas are constantly affecting each other.

Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta

Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan-gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan-gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region.

Different expression patterns of growth factors in rat fetuses with spina bifida aperta after in utero mesenchymal stromal cell transplantation

BACKGROUND AIMS

In a previous study, we successfully devised a prenatal surgical approach and transplanted mesenchymal stromal cells (MSCs) to fetal rat spinal column to treat retinoic acid-induced neural tube defects in rat. Our results show that MSCs survived, migrated and differentiated into neural lineage cells. We intended to study various growth factor expressions in rat fetal spinal cords with spina bifida aperta after in utero MSC transplantation and the effect of in vivo growth factor introduction for prenatal spina bifida treatment.

METHODS

Pregnant rats were treated with retinoic acid on embryonic day 10 and then received fetal surgery for MSC transplantation and/or lentiviral epidermal growth factor (EGF) injection on embryonic day 16; various growth factor expression in spinal cords from embryonic day 20 fetuses were analyzed by means of quantitative reverse transcriptase-polymerase chain reaction. Terminal deoxynucleotidyl transferase dUTP nick end labeling analysis was performed to observe spinal tissue apoptosis.

RESULTS

Growth factor expression was dysregulated in spinal cords with spina bifida. After MSC transplantation, we observed significantly increased expression of EGF, fibroblast growth factor (FGF)-8, FGF-2 and FGF-20 in the MSC transplantation group compared with blank injection; Furthermore, EGF expression positively correlated with surviving MSC amounts. Expression of other growth factors was not significantly different. In vivo EGF introduction reduced spinal tissue apoptosis.

CONCLUSIONS

Our results suggest that intrinsic EGF and FGF-2, FGF-8 and FGF-20 might affect the in vivo fate of transplanted MSCs in a fetal rat spina bifida model. In vivo EGF introduction together with MSC transplantation might serve as a new strategy for prenatal spina bifida treatment.

Fetal surgery for spina bifida: past, present, future

Open spina bifida or myelomeningocele (MMC) is a common birth defect that is associated with significant lifelong morbidity. Little progress has been made in the postnatal surgical management of the child with spina bifida. Postnatal surgery is aimed at covering the exposed spinal cord, preventing infection, and treating hydrocephalus with a ventricular shunt. Experimental and clinical evidence suggest that the primary cause of the neurologic defects associated with MMC is not simply incomplete neurulation, but rather chronic, mechanical and amniotic-fluid induced chemical trauma that progressively damages the exposed neural tissue during gestation. The cerebrospinal fluid leak through the MMC leads to hindbrain herniation and hydrocephalus. In utero repair of open spina bifida is now performed in selected patients and presents an additional therapeutic alternative for expectant mothers carrying a fetus with MMC. In the past, studies in animal models and clinical case series laid the groundwork for a clinical trial to test the safety and efficacy of fetal MMC repair. In the present, a prospective, randomized study (the MOMS trial) has shown that fetal surgery for MMC before 26 weeks' gestation may preserve neurologic function, reverse the hindbrain herniation of the Chiari II malformation, and obviate the need for postnatal placement of a ventriculoperitoneal shunt. However, this study also demonstrates that fetal surgery is associated with significant risks related to the uterine scar and premature birth. In the future, research will expand our understanding of the pathophysiology of MMC, evaluate the long-term impact of in-utero intervention, and to refine timing and technique of fetal MMC surgery using tissue engineering technology.