Prenatal stem cell transplantation and gene therapy

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.

Targeted drug delivery for maternal and perinatal health: Challenges and opportunities

Pre-existing conditions at reproductive age, and complications arising during pregnancy can be detrimental to maternal and fetal health. Current therapies to combat obstetric disorders are limited due to the inherent complexity of pregnancy, and can have harmful effects on developing fetus. Emerging research shows intricate signaling between the cells from mother and fetus at maternal-fetal interface, providing unique opportunities for interventions specifically targeted to the mother, fetus, or placenta. Advancements in nanotechnology, stem-cell biology and gene therapy have resulted in target-specific treatments with promising results in pre-clinical maternal and fetal disorder models. Comprehensive understanding of the effect of physicochemical properties of delivery systems on their uptake, retention and accumulation across placenta will help in the better diagnosis and treatment of perinatal disorders. This review describes the factors leading to obstetric complications along with their effect on pregnancy outcomes, and discusses key targeted therapeutic strategies for addressing conditions related to maternal and fetal health.

Evaluation of the effectiveness of infusion of bone marrow derived cell in patients with heart failure: A network meta-analysis of randomized clinical trials and cohort studies

Background: The aim of this study was to investigate the effectiveness of bone marrow-derived cells (BMC) technology in patients with heart failure and compare it with alternative therapies, including drug therapy, cardiac resynchronization therapy pacemaker (CRT-P), cardiac resynchronization therapy defibrillator (CRT-D).

Methods: A systematic review study was conducted to identify all clinical studies published by 2017. Using keywords such as "Heart Failure, BMC, Drug Therapy, CRT-D, CRT-P" and combinations of the mentioned words, we searched electronic databases, including Scopus, Cochrane Library, and PubMed. The quality of the selected studies was assessed using the Cochrane Collaboration's tool and the Newcastle-Ottawa. The primary and secondary end-points were left ventricular ejection fraction (LVEF) (%), failure cases (Number), left ventricular end-systolic volume (LVES) (ml), and left ventricular end-diastolic volume (LVED) (ml). Random-effects network meta-analyses were used to conduct a systematic comparison. Statistical analysis was done using STATA.

Results: This network meta-analysis covered a total of 57 final studies and 6694 patients. The Comparative effectiveness of BMC versus CRT-D, Drug, and CRT-P methods indicated the statistically significant superiority of BMC over CRT-P (6.607, 95% CI: 2.92, 10.29) in LVEF index and overall CRT-P (-13.946, 95% CI: -18.59, -9.29) and drug therapy (-4.176, 95% CI: -8.02, -.33) in LVES index. In addition, in terms of LVED index, the BMC had statistically significant differences with CRT-P (-10.187, 95% CI: -18.85, -1.52). BMC was also dominant to all methods in failure cases as a final outcome and the difference was statistically significant i.e. BMC vs CRT-D: 0.529 (0.45, 0.62) and BMC vs Drug: 0.516 (0.44, 0.60). In none of the outcomes, the other methods were statistically more efficacious than BMC. The BMC method was superior or similar to the other methods in all outcomes.

Conclusion: The results of this study showed that the BMC method, in general, and especially in terms of failure cases index, had a higher level of clinical effectiveness. However, due to the lack of data asymmetry, insufficient data and head-to-head studies, BMC in this meta-analysis might be considered as an alternative to existing treatments for heart failure.

Ultrasound-guided in Utero Transplantation of Placental Stem Cells into the Liver of Crigler-Najjar Syndrome Model Rat

BACKGROUND

Advances in prenatal screening and early diagnosis of genetic disease will potentially allow for preemptive treatment of anticipated postnatal disease by in utero cell transplantation (IUCT). This strategy carries potential benefits over postnatal treatment, which might allow for improved engraftment and function of the transplanted cells. Congenital metabolic disorders may be an ideal target for this type of therapy, as in most cases, they require replacement of a single deficient hepatic enzyme, and multiple small-animal models exist for preclinical testing.

METHODS

The Gunn rat, a Crigler-Najjar syndrome model animal lacking UDP-glucuronosyltransferase (UGT1A1), was used as recipient. Human amniotic epithelial cells (hAECs), which possess hepatic differentiation potential, were transplanted into the midgestation fetal Gunn rat liver via ultrasound-guided IUCT. The impact of IUCT on live birth and postnatal survival was evaluated. Human cell engraftment was immunohistochemically analyzed on postnatal day 21.

RESULTS

Ultrasound-guided IUCT was conducted in rat fetuses on embryonic day 16. Following IUCT, the antihuman mitochondria-positive cells were detected in the liver of recipient rats at postnatal day 21.

CONCLUSIONS

Here, we have introduced ultrasound-guided IUCT of hAEC using a small-animal model of a congenital metabolic disorder without immunosuppression. The immunological advantage of IUCT was demonstrated with xenogeneic IUCT. This procedure is suitable to conduct preclinical studies for exploring the feasibility and efficacy of ultrasound-guided transuterine cell injection using rodent disease models.

In utero stem cell transplantation and gene therapy: rationale, history, and recent advances toward clinical application

Recent advances in high-throughput molecular testing have made it possible to diagnose most genetic disorders relatively early in gestation with minimal risk to the fetus. These advances should soon allow widespread prenatal screening for the majority of human genetic diseases, opening the door to the possibility of treatment/correction prior to birth. In addition to the obvious psychological and financial benefits of curing a disease in utero, and thereby enabling the birth of a healthy infant, there are multiple biological advantages unique to fetal development, which provide compelling rationale for performing potentially curative treatments, such as stem cell transplantation or gene therapy, prior to birth. Herein, we briefly review the fields of in utero transplantation (IUTx) and in utero gene therapy and discuss the biological hurdles that have thus far restricted success of IUTx to patients with immunodeficiencies. We then highlight several recent experimental breakthroughs in immunology, hematopoietic/marrow ontogeny, and in utero cell delivery, which have collectively provided means of overcoming these barriers, thus setting the stage for clinical application of these highly promising therapies in the near future.

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.

The concept of prenatal gene therapy

This introductory chapter provides a short review of the ideas and practical approaches that have led to the present and perceived future development of prenatal gene therapy. It summarizes the advantages and the potential adverse effects of this novel preventive and therapeutic approach to the management of prenatal diseases. It also provides guidance to the range of conditions to which prenatal gene therapy may be applied and to the technical approaches, vectors, and societal/ethical considerations for this newly emerging field of Fetal Medicine.

Recent advances in fetal gene therapy

Over the first decade of this new millennium gene therapy has demonstrated clear clinical benefits in several diseases for which conventional medicine offers no treatment. Clinical trials of gene therapy for single gene disorders have recruited predominantly young patients since older subjects may have suffered irrevocablepathological changes or may not be available because the disease is lethal relatively early in life. The concept of fetal gene therapy is an extension of this principle in that diseases in which irreversible changes occur at or beforebirth can be prevented by gene supplementation or repair in the fetus or associated maternal tissues. This article ccnsiders the enthusiasm and skepticism held for fetal gene therapy and its potential for clinical application. It coversa spectrum of candidate diseases for fetal gene therapy including Pompe disease, Gaucher disease, thalassemia, congenital protein C deficiency and cystic fibrosis. It outlines successful and not-so-successful examples of fetal gene therapy in animal models. Finally the application and potential of fetal gene transfer as a fundamental research tool for developmental biology and generation of somatic transgenic animals is surveyed.

In utero hematopoietic cell transplantation for the treatment of congenital anomalies

In utero hematopoietic cell transplantation (IUHCTx) is a promising strategy for the treatment of common hematopoietic disorders and for inducing immune tolerance in the fetus. Although the efficacy of IUHCTx has been demonstrated in multiple small and large animal models, the clinical application of this technique in humans has had limited success. Recent studies in mice have demonstrated that the maternal immune system plays a critical role in limiting engraftment in the fetus. This article reviews the therapeutic rationale of IUHCTx, potential barriers to its applications, and recent experimental strategies to improve its clinical success.

Maternal-fetal surgery for structural malformations

Although most prenatally diagnosed correctable anatomic abnormalities are best addressed by surgical interventions after birth, the outcomes of a small number of severe structural malformations with predicted fetal demise or devastating sequelae postnatally may be improved by correction before birth. Consideration of maternal-fetal surgical intervention is restricted to those anatomic malformations that interfere with normal organ development and which, if alleviated, may permit normal development to proceed. Advances in prenatal diagnosis and technical innovations in the surgical approach to the fetus have resulted in an increase in the successful clinical application of fetal intervention over the past 3 decades. The purpose of this review is to describe the current status of maternal-fetal surgery, with a focus on the congenital anomalies most commonly treated by intervention before birth, and to highlight the key areas for further research in this evolving surgical specialty.

Stable human FIX expression after 0.9G intrauterine gene transfer of self-complementary adeno-associated viral vector 5 and 8 in macaques

Intrauterine gene transfer (IUGT) offers ontological advantages including immune naiveté mediating tolerance to the vector and transgenic products, and effecting a cure before development of irreversible pathology. Despite proof-of-principle in rodent models, expression efficacy with a therapeutic transgene has yet to be demonstrated in a preclinical nonhuman primate (NHP) model. We aimed to determine the efficacy of human Factor IX (hFIX) expression after adeno-associated-viral (AAV)-mediated IUGT in NHP. We injected 1.0-1.95 × 10(13) vector genomes (vg)/kg of self-complementary (sc) AAV5 and 8 with a LP1-driven hFIX transgene intravenously in 0.9G late gestation NHP fetuses, leading to widespread transduction with liver tropism. Liver-specific hFIX expression was stably maintained between 8 and 112% of normal activity in injected offspring followed up for 2-22 months. AAV8 induced higher hFIX expression (P = 0.005) and milder immune response than AAV5. Random hepatocellular integration was found with no hotspots. Transplacental spread led to low-level maternal tissue transduction, without evidence of immunotoxicity or germline transduction in maternal oocytes. A single intravenous injection of scAAV-LP1-hFIXco to NHP fetuses in late-gestation produced sustained clinically-relevant levels of hFIX with liver-specific expression and a non-neutralizing immune response. These data are encouraging for conditions where gene transfer has the potential to avert perinatal death and long-term irreversible sequelae.

In utero gene transfer to the mouse nervous system

The cellular and molecular environment present in the fetus and early newborn provides an excellent opportunity for effective gene transfer. Innate and pre-existing anti-vector immunity may be attenuated or absent and the adaptive immune system predisposed to tolerance towards xenoproteins. Stem cell and progenitor cell populations are abundant, active and accessible. In addition, for treatment of early lethal genetic diseases of the nervous system, the overarching advantage may be that early gene supplementation prevents the onset of irreversible pathological changes. Gene transfer to the fetal mouse nervous system was achieved, albeit inefficiently, as far back as the mid-1980s. Recently, improvements in vector design and production have culminated in near-complete correction of a mouse model of spinal muscular atrophy. In the present article, we review perinatal gene transfer from both a therapeutic and technological perspective.

Perinatal gene transfer to the liver

The liver acts as a host to many functions hence raising the possibility that any one may be compromised by a single gene defect. Inherited or de novo mutations in these genes may result in relatively mild diseases or be so devastating that death within the first weeks or months of life is inevitable. Some diseases can be managed using conventional medicines whereas others are, as yet, untreatable. In this review we consider the application of early intervention gene therapy in neonatal and fetal preclinical studies. We appraise the tools of this technology, including lentivirus, adenovirus and adeno-associated virus (AAV)-based vectors. We highlight the application of these for a range of diseases including hemophilia, urea cycle disorders such as ornithine transcarbamylase deficiency, organic acidemias, lysosomal storage diseases including mucopolysaccharidoses, glycogen storage diseases and bile metabolism. We conclude by assessing the advantages and disadvantages associated with fetal and neonatal liver gene transfer.

Genetic modification of airway progenitors after lentiviral gene delivery to the amniotic fluid of murine fetuses

Lentiviral vectors with the firefly luciferase or enhanced green fluorescent protein (EGFP) transgenes were delivered to the amniotic fluid of murine fetuses at Embryonic Day (E) 14.5 or E16.5. Whole-body imaging of luciferase recipients after birth demonstrated transgene expression in the peritoneal and thoracic regions. Organ imaging showed luciferase expression in lung, skin, stomach, and/or intestine. Histological immunofluorescence analysis of EGFP recipients demonstrated that small clusters (≤ three cells) of EGFP-positive epithelial cells were present in the large and small airways of recipients at up to 7 months (n = 11). There was no difference in the frequency of transgene expression in mice injected at E14.5 or E16.5 in respiratory or nonrespiratory organs. Analysis of the bronchoalveolar duct junctions on tissue sections of recipient mice identified multiple EGFP-positive epithelial cells. Cells coexpressing EGFP, Clara cell 10-kd protein, and surfactant protein C (SPC) were also found in lungs, consistent with the transduction of bronchoalveolar stem cells. Next, naphthalene lung injury in both luciferase and EGFP recipients was performed to determine whether transduced cells could contribute to tissue repair. In luciferase recipients, the whole-body luciferase signal increased 2- to 20-fold at 2 weeks after naphthalene treatment. Remarkably, immunohistological analysis of the lungs of EGFP recipients after lung injury repair demonstrated repopulation of airways with long stretches of EGFP-positive epithelial cells (n = 4). Collectively, these data demonstrate that lentiviral gene delivery to the amniotic fluid of murine fetuses genetically modifies long-lived epithelial progenitors capable of contributing to lung injury repair.