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43 result(s) for "Citra Mattar"
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Fetal gene therapy for neurodegenerative disease of infants
For inherited genetic diseases, fetal gene therapy offers the potential of prophylaxis against early, irreversible and lethal pathological change. To explore this, we studied neuronopathic Gaucher disease (nGD), caused by mutations in GBA . In adult patients, the milder form presents with hepatomegaly, splenomegaly and occasional lung and bone disease; this is managed, symptomatically, by enzyme replacement therapy. The acute childhood lethal form of nGD is untreatable since enzyme cannot cross the blood–brain barrier. Patients with nGD exhibit signs consistent with hindbrain neurodegeneration, including neck hyperextension, strabismus and, often, fatal apnea 1 . We selected a mouse model of nGD carrying a loxP -flanked neomycin disruption of Gba plus Cre recombinase regulated by the keratinocyte-specific K14 promoter. Exclusive skin expression of Gba prevents fatal neonatal dehydration. Instead, mice develop fatal neurodegeneration within 15 days 2 . Using this model, fetal intracranial injection of adeno-associated virus (AAV) vector reconstituted neuronal glucocerebrosidase expression. Mice lived for up to at least 18 weeks, were fertile and fully mobile. Neurodegeneration was abolished and neuroinflammation ameliorated. Neonatal intervention also rescued mice but less effectively. As the next step to clinical translation, we also demonstrated the feasibility of ultrasound-guided global AAV gene transfer to fetal macaque brains. In utero GBA gene therapy extends lifespan and provides long-lasting phenotypic amelioration in a mouse model of neuronopathic Gaucher disease. Fetal ultrasound-guided in utero gene vector delivery is also achieved in the non-human primate brain.
Nine years' experience of trial of labor after two previous cesarean sections at a tertiary hospital – A retrospective cohort study
The global cesarean section (CS) rate has increased to 21.1% between 1990 and 2018. In Singapore, the annual CS rate has increased by ~ 0.6%, reaching an overall rate of 37.4%. Almost one-third of all cesarean deliveries are performed for at least one previous CS. Women with two CSs are often denied a \"trial of vaginal delivery\" due to the increased risk of uterine scar rupture. This study aims to examine maternal and neonatal outcomes of women undergoing trials of labor following two CSs (TOLAC-2). We conducted a retrospective observational study of women with singleton, term pregnancies in cephalic presentation who underwent TOLAC-2 at the National University Hospital, Singapore, between September 2013 and June 2022. Data were obtained through a detailed review of electronic medical records. Among 898 women with two previous CSs, 7.0% (63/898) attempted TOLAC-2, of whom 55.6% (35/63) achieved a successful vaginal birth (VBAC-2). Successful TOLAC-2 was associated with a significantly shorter duration of active labor (5.0 vs. 7.7 h, p = 0.013) and lower estimated blood loss (242mLs vs. 423mLs, p ≤ 0.001) compared with failed TOLAC-2. There were no perinatal complications of uterine rupture, APGAR <7 at 5 minutes, meconium aspiration syndrome or hypoxic-ischemic encephalopathy. We observed a trend toward successful VBAC-2 in women with a history of prior vaginal birth (74.6% vs. 48.9% p = 0.07). In our cohort, more than half of the women attempting TOLAC-2 at term achieved a successful vaginal birth without serious perinatal or maternal complications. TOLAC-2 is a safe and reasonable option for appropriately selected women following adequate counseling, even in the absence of a prior vaginal delivery.
The Influence of Web-Based Tools on Maternal and Neonatal Outcomes in Pregnant Adolescents or Adolescent Mothers: Mixed Methods Systematic Review
Pregnant adolescent women increasingly seek support during pregnancy and the puerperium through digital platforms instead of the traditional support system of family, friends, and the community. However, it is uncertain whether digital, web-based tools are reliable and effective in providing information to the user on a variety of topics such as fetal development, pregnancy outcomes, delivery, and breastfeeding to improve maternal and infant outcomes. We aimed to identify web-based tools designed to promote knowledge, attitudes, and skills of pregnant adolescents or adolescent mothers and determine the efficacy of such web-based tools compared with conventional resources in promoting good pregnancy and infant outcomes. A systematic search was conducted using Medline, Scopus, CINAHL, and PsycINFO for articles published from January 2004 to November 2020 to identify randomized trials and observational studies that evaluated digital, web-based platforms to deliver resources to pregnant adolescents. All articles written in the author's languages were included. Two authors independently reviewed abstracts and full-text articles for inclusion and assessed study quality. Risk of bias in each study was assessed using appropriate tools recommended by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) and the Joanna Briggs Institute. We adopted a qualitative synthesis and presented the results in a narrative format due to the heterogenous nature of the studies. Seven articles met the inclusion criteria and were analyzed. The majority of the studies were graded to be of low to moderate risk for bias. The research methodologies represented were varied, ranging from randomized (n=1) and nonrandomized controlled trials (n=1) and prospective cohort studies (n=1) to mixed methods studies (n=1) and longitudinal surveys (n=3). Four studies included active web-based interventions, and 3 described exposure to web-based tools, including the use of social media and/or other internet content. Web-based tools positively influenced treatment-seeking intentions (intervention 17.1%, control 11.5%, P=.003) and actual treatment-seeking behavior for depression among postpartum adolescents (intervention 14.1%, control 6.5%, P<.001). In contrast, readily available information on the internet may leave adolescents with increased anxiety. The critical difference lies in information curated by health care professionals specifically to address targeted concerns versus self-acquired data sourced from various websites. Despite almost universal web use, few studies have used this platform for health promotion and disease prevention. Social media interventions or web-based tools have the potential to positively influence both maternal and infant outcomes in adolescent pregnancy, but there is a need for more well-conducted studies to demonstrate the effectiveness of these support programs. The vastness of the information available on the web limits the ability of health care professionals to monitor or control sources of information sought by patients. Thus, it is important to create professionally curated platforms to prevent or limit exposure to potentially misleading or harmful information on the internet while imparting useful knowledge to the user. PROSPERO International Prospective Register of Systematic Reviews CRD42020195854; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=195854.
Mending a broken heart: In vitro , in vivo and in silico models of congenital heart disease
Birth defects contribute to ∼0.3% of global infant mortality in the first month of life, and congenital heart disease (CHD) is the most common birth defect among newborns worldwide. Despite the significant impact on human health, most treatments available for this heterogenous group of disorders are palliative at best. For this reason, the complex process of cardiogenesis, governed by multiple interlinked and dose-dependent pathways, is well investigated. Tissue, animal and, more recently, computerized models of the developing heart have facilitated important discoveries that are helping us to understand the genetic, epigenetic and mechanobiological contributors to CHD aetiology. In this Review, we discuss the strengths and limitations of different models of normal and abnormal cardiogenesis, ranging from single-cell systems and 3D cardiac organoids, to small and large animals and organ-level computational models. These investigative tools have revealed a diversity of pathogenic mechanisms that contribute to CHD, including genetic pathways, epigenetic regulators and shear wall stresses, paving the way for new strategies for screening and non-surgical treatment of CHD. As we discuss in this Review, one of the most-valuable advances in recent years has been the creation of highly personalized platforms with which to study individual diseases in clinically relevant settings.
In Utero Transfer of Adeno-Associated Viral Vectors Produces Long-Term Factor IX Levels in a Cynomolgus Macaque Model
The safe correction of an inherited bleeding disorder in utero prior to the onset of organ damage is highly desirable. Here, we report long-term transgene expression over more than 6 years without toxicity following a single intrauterine gene transfer (IUGT) at 0.9G using recombinant adeno-associated vector (AAV)-human factor IX (hFIX) in the non-human primate model we have previously described. Four of six treated animals monitored for around 74 months expressed hFIX at therapeutic levels (3.9%–120.0%). Long-term expression was 6-fold higher in males and with AAV8 compared to AAV5, mediated almost completely at this stage by random genome-wide hepatic proviral integrations, with no evidence of hotspots. Post-natal AAV challenge without immunosuppression was evaluated in two animals exhibiting chronic low transgene expression. The brief neutralizing immune reaction elicited had no adverse effect and, although expression was not improved at the dose administered, no clinical toxicity was observed. This long-term surveillance thus confirms the safety of late-gestation AAV-hFIX transfer and demonstrates that postnatal re-administration can be performed without immunosuppression, although it requires dose optimization for the desired expression. Nevertheless, eventual vector genotoxicity and the possibility of germline transmission will require lifelong monitoring and further evaluation of the reproductive function of treated animals. Mattar et al. present long-term data from a macaque model of intrauterine AAV-hFIX gene transfer demonstrating sustained therapeutic hFIX expression from a generally integrated vector, differential efficacy in males and females, and immune tolerance to postnatal AAV administration, and establish the safety of this intervention through an absence of hepatotoxicity and tumorigenesis.
Pre‐ and Postnatal Transplantation of Fetal Mesenchymal Stem Cells in Osteogenesis Imperfecta: A Two‐Center Experience
This study reports the clinical course of two patients with osteogenesis imperfecta who received prenatal human fetal mesenchymal stem cell (MSC) transplantation and postnatal boosting with same‐donor MSCs. Findings suggest that prenatal transplantation of allogeneic human fetal MSCs in osteogenesis imperfecta appears safe and is of likely clinical benefit and that retransplantation with same‐donor cells is feasible. Further studies are required. Osteogenesis imperfecta (OI) can be recognized prenatally with ultrasound. Transplantation of mesenchymal stem cells (MSCs) has the potential to ameliorate skeletal damage. We report the clinical course of two patients with OI who received prenatal human fetal MSC (hfMSC) transplantation and postnatal boosting with same‐donor MSCs. We have previously reported on prenatal transplantation for OI type III. This patient was retransplanted with 2.8 × 106 same‐donor MSCs per kilogram at 8 years of age, resulting in low‐level engraftment in bone and improved linear growth, mobility, and fracture incidence. An infant with an identical mutation who did not receive MSC therapy succumbed at 5 months despite postnatal bisphosphonate therapy. A second fetus with OI type IV was also transplanted with 30 × 106 hfMSCs per kilogram at 31 weeks of gestation and did not suffer any new fractures for the remainder of the pregnancy or during infancy. The patient followed her normal growth velocity until 13 months of age, at which time longitudinal length plateaued. A postnatal infusion of 10 × 106 MSCs per kilogram from the same donor was performed at 19 months of age, resulting in resumption of her growth trajectory. Neither patient demonstrated alloreactivity toward the donor hfMSCs or manifested any evidence of toxicities after transplantation. Our findings suggest that prenatal transplantation of allogeneic hfMSCs in OI appears safe and is of likely clinical benefit and that retransplantation with same‐donor cells is feasible. However, the limited experience to date means that it is not possible to be conclusive and that further studies are required.
Maternal dendritic cells influence fetal allograft response following murine in-utero hematopoietic stem cell transplantation
Background Intrauterine hematopoietic stem cell transplantation (IUT), potentially curative in congenital haematological disease, is often inhibited by deleterious immune responses to donor cells resulting in subtherapeutic donor cell chimerism (DCC). Microchimerism of maternal immune cells (MMc) trafficked into transplanted recipients across the placenta may directly influence donor-specific alloresponsiveness, limiting DCC. We hypothesized that dendritic cells (DC) among trafficked MMc influence the development of tolerogenic or immunogenic responses towards donor cells, and investigated if maternal DC-depletion reduced recipient alloresponsiveness and enhanced DCC. Methods Using transgenic CD11c.DTR (C57BL/6) female mice enabled transient maternal DC-depletion with a single dose of diphtheria toxin (DT). CD11c.DTR females and BALB/c males were cross-mated, producing hybrid pups. IUT was performed at E14 following maternal DT administration 24 h prior. Bone marrow-derived mononuclear cells were transplanted, obtained from semi-allogenic BALB/c (paternal-derived; pIUT), C57BL/6 (maternal-derived; mIUT), or fully allogenic (aIUT) C3H donor mice. Recipient F1 pups were analyzed for DCC, while maternal and IUT-recipient immune cell profile and reactivity were examined via mixed lymphocyte reactivity functional assays. T- and B-cell receptor repertoire diversity in maternal and recipient cells were examined following donor cell exposure. Results DCC was highest and MMc was lowest following pIUT. In contrast, aIUT recipients had the lowest DCC and the highest MMc. In groups that were not DC-depleted, maternal cells trafficked post-IUT displayed reduced TCR & BCR clonotype diversity, while clonotype diversity was restored when dams were DC-depleted. Additionally, recipients displayed increased expression of regulatory T-cells and immune-inhibitory proteins, with reduced proinflammatory cytokine and donor-specific antibody production. DC-depletion did not impact initial donor chimerism. Postnatal transplantation without immunosuppression of paternal donor cells did not increase DCC in pIUT recipients; however there were no donor-specific antibody production or immune cell changes. Conclusions Though maternal DC depletion did not improve DCC, we show for the first time that MMc influences donor-specific alloresponsiveness, possibly by expanding alloreactive clonotypes, and depleting maternal DC promotes and maintains acquired tolerance to donor cells independent of DCC, presenting a novel approach to enhancing donor cell tolerance following IUT. This may have value when planning repeat HSC transplantations to treat haemoglobinopathies.
Interpreting the role of nuchal fold for fetal growth restriction prediction using machine learning
The objective of the study is to investigate the effect of Nuchal Fold (NF) in predicting Fetal Growth Restriction (FGR) using machine learning (ML), to explain the model's results using model-agnostic interpretable techniques, and to compare the results with clinical guidelines. This study used second-trimester ultrasound biometry and Doppler velocimetry were used to construct six FGR (birthweight < 3rd centile) ML models. Interpretability analysis was conducted using Accumulated Local Effects (ALE) and Shapley Additive Explanations (SHAP). The results were compared with clinical guidelines based on the most optimal model. Support Vector Machine (SVM) exhibited the most consistent performance in FGR prediction. SHAP showed that the top contributors to identify FGR were Abdominal Circumference (AC), NF, Uterine RI (Ut RI), and Uterine PI (Ut PI). ALE showed that the cutoff values of Ut RI, Ut PI, and AC in differentiating FGR from normal were comparable with clinical guidelines (Errors between model and clinical; Ut RI: 15%, Ut PI: 8%, and AC: 11%). The cutoff value for NF to differentiate between healthy and FGR is 5.4 mm, where low NF may indicate FGR. The SVM model is the most stable in FGR prediction. ALE can be a potential tool to identify a cutoff value for novel parameters to differentiate between healthy and FGR.
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 × 1013 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.
Regionally-Specified Second Trimester Fetal Neural Stem Cells Reveals Differential Neurogenic Programming
Neural stem/progenitor cells (NSC) have the potential for treatment of a wide range of neurological diseases such as Parkinson Disease and multiple sclerosis. Currently, NSC have been isolated only from hippocampus and subventricular zone (SVZ) of the adult brain. It is not known whether NSC can be found in all parts of the developing mid-trimester central nervous system (CNS) when the brain undergoes massive transformation and growth. Multipotent NSC from the mid-trimester cerebra, thalamus, SVZ, hippocampus, thalamus, cerebellum, brain stem and spinal cord can be derived and propagated as clonal neurospheres with increasing frequencies with increasing gestations. These NSC can undergo multi-lineage differentiation both in vitro and in vivo, and engraft in a developmental murine model. Regionally-derived NSC are phenotypically distinct, with hippocampal NSC having a significantly higher neurogenic potential (53.6%) over other sources (range of 0%-27.5%, p<0.004). Whole genome expression analysis showed differential gene expression between these regionally-derived NSC, which involved the Notch, epidermal growth factor as well as interleukin pathways. We have shown the presence of phenotypically-distinct regionally-derived NSC from the mid-trimester CNS, which may reflect the ontological differences occurring within the CNS. Aside from informing on the role of such cells during fetal growth, they may be useful for different cellular therapy applications.