Preclinical stem cell therapy in fetuses with myelomeningocele: A systematic review and meta-analysis

Amniotic fluid-derived stem cells: potential factories of natural and mimetic strategies for congenital malformations

Background

Mesenchymal stem cells (MSCs) from gestational tissues represent promising strategies for in utero treatment of congenital malformations, but plasticity and required high-risk surgical procedures limit their use. Here we propose natural exosomes (EXOs) isolated from amniotic fluid-MSCs (AF-MSCs), and their mimetic counterparts (MIMs), as valid, stable, and minimally invasive therapeutic alternatives.

Methods

MIMs were generated from AF-MSCs by combining sequential filtration steps through filter membranes with different porosity and size exclusion chromatography columns. Physiochemical and molecular characterization was performed to compare them to EXOs released from the same number of cells. The possibility to exploit both formulations as mRNA-therapeutics was explored by evaluating cell uptake (using two different cell types, fibroblasts, and macrophages) and mRNA functionality overtime in an in vitro experimental setting as well as in an ex vivo, whole embryo culture using pregnant C57BL6 dams.

Results

Molecular and physiochemical characterization showed no differences between EXOs and MIMs, with MIMs determining a 3-fold greater yield. MIMs delivered a more intense and prolonged expression of mRNA encoding for green fluorescent protein (GFP) in macrophages and fibroblasts. An ex-vivo whole embryo culture demonstrated that MIMs mainly accumulate at the level of the yolk sac, while EXOs reach the embryo.

Conclusions

The present data confirms the potential application of EXOs for the prenatal repair of neural tube defects and proposes MIMs as prospective vehicles to prevent congenital malformations caused by in utero exposure to drugs.

Trends in research related to fetal therapy from 2012 to 2022: a bibliometric analysis

Background

The development of prenatal diagnosis technology allows prompt detection of severe fetal diseases. To address adverse factors that threaten fetal survival, fetal therapy came into existence, which aims to preserve the function after birth to a higher degree and improve the quality of life.

Objective

To conduct a comprehensive bibliometric analysis of studies on fetal therapy in the past decade and explore the research trends and hotspots in this field.

Methods

We conducted a systematic search on the Web of Science Core Collection to retrieve studies related to fetal therapy published from 2012 to 2022. VOSviewer and CiteSpace were used to analyze the key features of studies, including annual output, countries/regions, institutions, authors, references, research hotspots, and frontiers.

Results

A total of 9,715 articles were included after eliminating duplicates. The annual distribution of the number of articles showed that the number of articles published in fetal therapy had increased in the past decade. Countries and institutions showed that fetal therapy is more mature in the United States. Author analysis showed the core investigators in the field. Keyword analysis showed the clustering and emergence frequency, which helped summarize the research results and frontier hotspots in this field. The cocited references were sorted out to determine the literature with a high ranking of fetal therapy in recent years, and the research trend in recent years was analyzed.

Conclusions

This study reveals that countries, institutions, and researchers should promote wider cooperation and establish multicenter research cooperation in fetal therapy research. Moreover, fetal therapy has been gradually explored from traditional surgical treatment to gene therapy and stem cell therapy. In recent years, fetoscopic laser surgery, guideline, and magnetic resonance imaging have become the research hotspots in the field.

Outcomes of autologous bone marrow mononuclear cell administration in the treatment of neurologic sequelae in children with spina bifida

BACKGROUND

To evaluate the safety and efficacy of autologous bone marrow mononuclear cell (BMMNC) infusion in the management of neurological sequelae in children with spina bifida (SB).

METHODS

BMMNCs were harvested from bilateral anterior iliac crests. Two intrathecal BMMNC administrations were performed with an interval of 6 months. The measurements of outcomes included clinical assessments, cystomanometry and rectomanometry.

RESULTS

Eleven children with SB underwent autologous BMMNC infusions from 2016 to 2020. There were no severe adverse events during the study period. The number of patients requiring assistance to expel stools decreased from 11 before cell infusion to 3 after the second cell infusion. The number of patients who had urine leakage decreased from 9 patients at baseline to 3 patients after the second BMMNC infusion. The mean bladder capacity increased from 127.7 ± 59.2 ml at baseline to 136.3 ± 54.8 ml at six months and to 158.3 ± 56.2 ml at 12 months after BMMNC infusions. Detrusor pressure (pdet) decreased from 32.4 ± 22.0 cm H₂O at baseline to 21.9 ± 11.8 cm H₂O after 12 months of follow-up. At baseline, six patients could walk independently. After the 2nd infusion, eight patients could walk independently.

CONCLUSION

Intrathecal infusions of autologous bone marrow mononuclear cells are safe and may improve bowel, bladder, and motor function in children with SB.

TRIAL REGISTRATION

NCT, NCT05472428. Registered July 25, 2022- Retrospectively registered, https://www.

CLINICALTRIALS

gov/ct2/show/NCT05472428 .

Fetal Surgery for Myelomeningocele: Neurosurgical Perspectives

More than 30 years have elapsed since it was recognised that folic acid supplementation could substantially reduce the risk of open neural tube defects (ONTDs). During that time, many countries have adopted policies of food fortification with demonstrable reduction in the incidence of both cranial and spinal ONTDs. Improved prenatal detection and termination has also resulted in a reduction in the number of affected live births. Nonetheless, in the USA about 1500 children, and in the UK around 500 children are born each year with myelomeningocele (MMC) and so the management of MMC and its complications continues to constitute a significant clinical workload for many paediatric neurosurgical units around the world.Until recently, the options available following antenatal diagnosis of MMC were termination of pregnancy or postnatal repair. As a result of the MOMS trial, prenatal repair has become an additional option in selected cases (Adzick et al., N Engl J Med 364(11):993-1004, 2011). Fetal surgery for myelomeningocele is now offered in more than 30 centres worldwide. The aim of this chapter is to review the experimental basis of prenatal repair of MMC, to critically evaluate the neurosurgical implications of this intervention and to describe the technique of 'open' repair, comparing this with emerging minimally invasive alternatives.

Fetal Neurosurgical Interventions for Spinal Malformations, Cerebral Malformations, and Hydrocephalus: Past, Present, and Future

In this article we review the last 40 years of progress in fetal neurosurgery with special attention to current controversies and upcoming challenges in the field. We surveyed the published literature describing prenatal interventions for spinal malformations, cerebral malformations, and hydrocephalus. Even the most mature treatment paradigm, intrauterine repair of myelomeningocele, stands to benefit from advances in imaging and therapeutic modalities to improve patient selection, refine surgical techniques, validate novel biologic therapies, and streamline postoperative patient care. Other conditions under evaluation include congenital cerebral malformations, such as encephalocele, cerebrovascular malformations, and hydrocephalus. We describe cross-cutting needs for advances in fetal neuroimaging, basic disease models and new therapeutic devices to support further progress across various neurosurgical conditions affecting patients during the fetal period.

Long-term safety evaluation of placental mesenchymal stromal cells for in utero repair of myelomeningocele in a novel ovine model

PURPOSE

Augmentation of in utero myelomeningocele repair with human placental mesenchymal stromal cells seeded onto extracellular matrix (PMSC-ECM) improves motor outcomes in an ovine myelomeningocele model. This study evaluated the safety of PMSC-ECM application directly onto the fetal spinal cord in preparation for a clinical trial.

METHODS

Laminectomy of L5-L6 with PMSC-ECM placement directly onto the spinal cord was performed in five fetal lambs at gestational age (GA) 100-106 days. Lambs and ewes were monitored for three months following delivery. Lambs underwent magnetic resonance imaging (MRI) of the brain and spine at birth and at three months. All organs from lambs and uteri from ewes underwent histologic evaluation. Lamb spinal cords and brains and ewe placentas were evaluated for persistence of PMSCs by polymerase chain reaction for presence of human DNA.

RESULTS

MRIs demonstrated no evidence of abnormal tissue growth or spinal cord tethering. Histological analysis demonstrated no evidence of abnormal tissue growth or treatment related adverse effects. No human DNA was identified in evaluated tissues.

CONCLUSION

There was no evidence of abnormal tissue growth or PMSC persistence at three months following in utero application of PMSC-ECM to the spinal cord. This supports proceeding with clinical trials of PMSC-ECM for in utero myelomeningocele repair.

LEVEL OF EVIDENCE

N/A TYPE OF STUDY: Basic science.

Comprehensive Profiling of Secretome Formulations from Fetal- and Perinatal Human Amniotic Fluid Stem Cells

We previously reported that c-KIT+ human amniotic-fluid derived stem cells obtained from leftover samples of routine II trimester prenatal diagnosis (fetal hAFS) are endowed with regenerative paracrine potential driving pro-survival, anti-fibrotic and proliferative effects. hAFS may also be isolated from III trimester clinical waste samples during scheduled C-sections (perinatal hAFS), thus offering a more easily accessible alternative when compared to fetal hAFS. Nonetheless, little is known about the paracrine profile of perinatal hAFS. Here we provide a detailed characterization of the hAFS total secretome (i.e., the entirety of soluble paracrine factors released by cells in the conditioned medium, hAFS-CM) and the extracellular vesicles (hAFS-EVs) within it, from II trimester fetal- versus III trimester perinatal cells. Fetal- and perinatal hAFS were characterized and subject to hypoxic preconditioning to enhance their paracrine potential. hAFS-CM and hAFS-EV formulations were analyzed for protein and chemokine/cytokine content, and the EV cargo was further investigated by RNA sequencing. The phenotype of fetal- and perinatal hAFS, along with their corresponding secretome formulations, overlapped; yet, fetal hAFS showed immature oxidative phosphorylation activity when compared to perinatal ones. The profiling of their paracrine cargo revealed some differences according to gestational stage and hypoxic preconditioning. Both cell sources provided formulations enriched with neurotrophic, immunomodulatory, anti-fibrotic and endothelial stimulating factors, and the immature fetal hAFS secretome was defined by a more pronounced pro-vasculogenic, regenerative, pro-resolving and anti-aging profile. Small RNA profiling showed microRNA enrichment in both fetal- and perinatal hAFS-EV cargo, with a stably- expressed pro-resolving core as a reference molecular signature. Here we confirm that hAFS represents an appealing source of regenerative paracrine factors; the selection of either fetal or perinatal hAFS secretome formulations for future paracrine therapy should be evaluated considering the specific clinical scenario.