Respiratory Severity Score and Oxygen Saturation Index during the First 2 Hours of Life as Predictors for Noninvasive Respiratory Support Failure in Respiratory Distress Syndrome.

OBJECTIVE: Noninvasive respiratory support (NRS) failure is common in preterm infants with respiratory distress syndrome (RDS). We evaluated the utility of respiratory severity score (RSS) and oxygen saturation index (OSI) during the first 2 hours of life (HOL) as predictors for NRS failure in moderate preterm infants. STUDY DESIGN: We conducted a retrospective cohort study of infants born between 280/7 and 336/7 weeks with RDS. Univariate and multivariable logistic regression analyses were used to assess whether the RSS and OSI summary measures were associated with NRS failure. RESULTS: A total of 282 infants were included in the study. Median gestational age and birth weights were 32 weeks and 1.7 kg, respectively. Fifty-eight infants (21%) developed NRS failure at the median age of 10.5 hours. RSS and OSI summary measures in the first 2 HOL were associated with NRS failure within 72 HOL. CONCLUSION: RSS and OSI during the first 2 HOL can predict NRS failure. Optimal RSS and OSI cutoffs for the prediction of NRS failure need to be determined in large cohort studies. KEY POINTS: · Nearly one in five moderate preterm infants on NRS at 2 hours of life developed NRS failure.. · RSS and OSI during the first 2 HOL can predict NRS failure.. · Optimal RSS and OSI cutoffs for the prediction of NRS failure need to be determined..

Respiratory Severity Score during the First 3 Hours of Life as a Predictor for Failure of Noninvasive Respiratory Support and Need for Late Rescue Surfactant Administration.

OBJECTIVE: Preterm infants often develop failure of noninvasive respiratory support. These infants miss the advantages of early rescue surfactant therapy. In this study, we evaluate the utility of respiratory severity score (RSS) during the first 3 hours of life (HOL) as a predictor for failure of noninvasive respiratory support. STUDY DESIGN: We conducted a post hoc analysis of infants between 23 and 40 weeks' gestational age who received usual care in the AERO-02 clinical trial. Univariate and multivariable logistic regression analysis were used to assess whether the RSS summary measures were associated with the odds of surfactant administration. RESULTS: Study involved 146 infants. Sixty-four infants (45%) received surfactant within the first 72 hours. Administration of surfactant was associated with the mean RSS (p < 0.01) and the linear trend (p < 0.01). CONCLUSION: We demonstrated that RSS during the first 3 HOL can predict failure of noninvasive respiratory support and need for late rescue surfactant administration. Optimal RSS cutoffs for early rescue surfactant therapy need to be determined in large cohort studies. KEY POINTS: · Early recognition of infants at risk of failure of noninvasive ventilation is important to prevent complications.. · It is desirable to identify patients who would benefit from early rescue surfactant treatment.. · RSS in first 3 hours can be used as a predictor of failure of noninvasive respiratory support..

Postnatal Age Is a Critical Determinant of the Neonatal Host Response to Sepsis.

Neonates manifest a unique host response to sepsis even among other children. Preterm neonates may experience sepsis soon after birth or during often-protracted birth hospitalizations as they attain physiologic maturity. We examined the transcriptome using genome-wide expression profiling on prospectively collected peripheral blood samples from infants evaluated for sepsis within 24 h after clinical presentation. Simultaneous plasma samples were examined for alterations in inflammatory mediators. Group designation (sepsis or uninfected) was determined retrospectively on the basis of clinical exam and laboratory results over the next 72 h from the time of evaluation. Unsupervised analysis showed the major node of separation between groups was timing of sepsis episode relative to birth (early, <3 d, or late, ≥3 d). Principal component analyses revealed significant differences between patients with early or late sepsis despite the presence of similar key immunologic pathway aberrations in both groups. Unique to neonates, the uninfected state and host response to sepsis is significantly affected by timing relative to birth. Future therapeutic approaches may need to be tailored to the timing of the infectious event based on postnatal age.

Surfactant delivery by aerosol inhalation - past, present, and future.

Surfactant replacement therapy (SRT) by nebulization to spontaneously breathing patients has been regarded as the Holy Grail since surfactant deficiency was first identified as the cause for neonatal respiratory distress syndrome. It avoids neonatal endotracheal intubation, a procedure that is often difficult and occasionally harmful. Unapproved alternatives to endotracheal tube placement for liquid surfactant instillation, such as LISA (thin catheter intubation) and SALSA (supraglottic airway insertion) have significant merit but are still invasive, leaving nebulized SRT as the only truly non-invasive method. In the past 60 years, we have learned much about the potential - and limitations - of nebulized SRT. In this review, we examine the promises and pitfalls of nebulized SRT, discuss what we know about neonatal aerosol drug delivery and recap some of the most recent randomized clinical trials of nebulized SRT. We conclude with a discussion of what is known and the next steps needed if this type of SRT is to become a regular part of clinical care.

Predictors of successful treatment of respiratory distress with aerosolized calfactant.

INTRODUCTION: Predictors for successful aerosolized surfactant treatment are not well defined. OBJECTIVE: To identify predictors for successful treatment in the AERO-02 trial and the AERO-03 expanded access program. METHODS: Neonates receiving nasal continuous positive airway pressure (NCPAP) at the time of first aerosolized calfactant administration were included in this analysis. Associations between demographic and clinical predictors to need for intubation were examined using univariate testing and multivariate logistic regression analyses. RESULTS: Three hundred and eighty infants were included in the study. Overall, 24% required rescue by intubation. Multivariate modeling revealed that the predictors of successful treatment were a gestational age ≥31 weeks, a respiratory severity score (RSS) of <1.9, and <2 previous aerosol treatments. CONCLUSION: Gestational age, number of aerosols, and RSS are predictive of successful treatment. These criteria will help select patients most likely to benefit from aerosolized surfactant.

Response to aerosolized calfactant in infants with respiratory distress syndrome; a post-hoc analysis of AERO-02 trial.

BACKGROUND: The aerosolized calfactant decreased the need for intubation in neonates with respiratory distress syndrome (AERO-02 trial). OBJECTIVE: To determine the oxygenation response to aerosolized calfactant among infants born 28 0/7-36 6/7 weeks with RDS in the AERO-02 trial. METHODS: Trends in hourly fraction of oxygen (FiO2), mean airway pressure (MAP) and respiratory severity score (RSS) were compared between the aerosolized calfactant (AC) and usual care (UC) groups from time of randomization for 72 h. RESULTS: A total of 353 subjects were included in the study. FiO2, MAP, and RSS were lower in the UC group. FiO2 decrease was seen after the first aerosolized calfactant dose. CONCLUSION: FiO2, MAP, and RSS were lower in the UC group. This is likely due to early and higher rate of liquid surfactant administration in the UC group. Decrease in FiO2 was noted in the AC group after the first aerosolization.

Incidence and types of congenital heart disease at a referral hospital in Jordan: retrospective study from a tertiary center.

Background: Congenital heart disease (CHD) is the most common birth defect and accounts for significant global morbidity and mortality. Relatively little is known about the epidemiology of CHD in Jordan or the manner in which CHD is identified. Methods: A retrospective medical record review was conducted for all neonates who had an abnormal echocardiogram performed at a tertiary referral hospital. All included neonates had echocardiography performed by the same pediatric cardiologist at the discretion of the treatment team. Descriptive statistics were used to describe CHD incidence, types of CHD identified, and mechanism of identification. Results: The incidence of congenital heart disease was 17.8 per 1,000 live births. This rose to 24.6 per 1,000 if patent ductus arteriosus in preterm infants was included. The most common identified abnormalities were PDA, atrial septal defects, persistent pulmonary hypertension, septal hypertrophy, and ventricular septal defects. Most children were evaluated either for a murmur heard on exam or as a part of screening due to other comorbidities or risk factors. Less than 1% of children had a prenatal diagnosis. There was a higher rate of persistent pulmonary hypertension during the COVID-19 pandemic than before (p < 0.001). Conclusions: There is a high incidence of CHD in Jordan. Increased prenatal and perinatal screening for CHD may allow for earlier detection.

Surfactant Administration Through Laryngeal or Supraglottic Airways (SALSA): A Viable Method for Low-Income and Middle-Income Countries.

Administration of liquid surfactant through an endotracheal tube for the treatment of respiratory distress syndrome has been the standard of care for decades. A skilled health care provider is needed to perform this procedure. In lower-income and middle-income countries (LMICs), healthcare resources are often limited, leading to increased mortality of premature infants, many of whom would benefit from surfactant administration. Therefore, having a simplified procedure for delivery of surfactant without the need for advanced skills could be life-saving, potentially diminish gaps in care, and help ensure more equitable global neonatal survival rates. Modifications to the standard approach of surfactant administration have been put into practice and these include: INtubation-SURfactant-Extubation (INSURE), thin catheter surfactant administration (TCA), aerosolized surfactant, and surfactant administration through laryngeal or supraglottic airways (SALSA). Although there is a need for larger studies to evaluate the comparative effectiveness of these newer methods, these methods are being embraced by the global community and being implemented in various settings throughout the world. Because the SALSA technique does not require laryngoscopy, a provider skilled in laryngoscopy is not required for the procedure. Therefore, because of the ease of use and safety profile, the SALSA technique should be strongly considered as a viable method of delivering surfactant in LMICs.

Factors associated with initial tidal volume selection during neonatal volume-targeted ventilation in two NICUs: a retrospective cohort study.

OBJECTIVE: To quantify initial tidal volume (VT) during neonatal volume-targeted ventilation (VTV) and to characterize the agreement of initial VT with the limited-evidence available. STUDY DESIGN: We performed a multi-center retrospective observational cohort study in two Neonatal Intensive Care Units evaluating 313 infants who received VTV as the initial ventilation modality prior to postnatal day 14. We generated descriptive statistics and performed multivariable logistic regression analysis to determine factors associated with initial VT use that agreed with available literature. RESULTS: 154 (49%) infants received an initial VT of 5.0 mL/kg (median 5.0 mL/kg, IQR 5.0-5.1). 45 (14%) infants received an initial VT that was congruent with available literature. A birth weight of 700 -<1250 g was significantly associated with an initial VT in agreement with VT literature (aOR 9.4, 95% CI 1.7-50.4). CONCLUSIONS: Most infants receive an initial VT of 5.0 mL/kg.

Implementation of Surfactant Administration through Laryngeal or Supraglottic Airways (SALSA): A Jordanian NICU's Journey to Improve Surfactant Administration.

Administration of liquid surfactant through an endotracheal tube for the treatment of respiratory distress syndrome has been the standard of care for decades. Surfactant administration through laryngeal or supraglottic airways (SALSA) is a simplified procedure for delivery of surfactant that is less invasive and better tolerated. The Al Bashir Maternity and Children's Hospital NICU in Amman, Jordan, implemented SALSA as a potentially better practice in 2019 with the objective to effectively and efficiently deliver surfactant in a minimally invasive way and to decrease the adverse events associated with intubation−surfactant−extubation (InSurE) and laryngoscopy. The quality improvement initiative was conducted from March 2019 to December 2019. All infants who weighed 750 g or more who required surfactant were eligible. As physicians were trained in the technique and use expanded, we were able to use plan−do−study−act cycles to observe differences between SALSA and InSurE. The primary aim was the optimization of non-invasive ventilation by the effective and efficient delivery of surfactant. Balancing measures included episodes of bradycardia while receiving surfactant or the need for a second dose of surfactant. We evaluated 220 infants who received surfactant by SALSA or InSurE with a mean gestational age of 32 weeks and a mean birth weight of 1.8 kg. The Respiratory Severity Score (RSS) prior to surfactant administration was 2.7 in the SALSA group compared to 2.9 in the InSurE group (p = 0.024). Those in the InSurE group had a lower mean heart rate during the procedure (p =< 0.0001) and were more likely to need a second dose of surfactant (p = 0.026) or require intubation for mechanical ventilation (p = 0.022). Both groups were effectively delivered surfactant as evidenced by improvement in their RSS over an 8 h period. SALSA was a more time efficient surfactant delivery method (93 vs. 111 secs, p =< 0.0001). Implementation of SALSA into the Al Bashir NICU was successful. We found that it was equally effective to InSurE, but was a more efficient method of delivery. Infants who received surfactant by this method tolerated it well.

Surfactant Administration Through Laryngeal or Supraglottic Airways.

Noninvasive ventilation is frequently used in the treatment of infants with respiratory distress syndrome. This practice is often effective in higher gestational age neonates, but can be difficult in those with lower gestational ages as surfactant deficiency can be severe. While noninvasive ventilation avoids the negative effects of intubation and ventilator-induced lung injury, failure of this mode of support does occur with relative frequency and is primarily caused by the poorly compliant, surfactant-deficient lung. Because of the potential problems associated with laryngoscopy and intubation, neonatologists have developed various methods to deliver surfactant in minimally invasive ways with the aim of improving the success of noninvasive ventilation. Methods of minimally invasive surfactant administration include various thin catheter techniques, aerosolization/nebulization, and the use of a laryngeal mask airway/supraglottic airway device. The clinician should recognize that currently the only US Food and Drug Administration-approved device to deliver surfactant is an endotracheal tube and all methods reviewed here are considered off-label use. This review will focus primarily on surfactant administration through laryngeal or supraglottic airways, providing a review of the history of this technique, animal and human trials, and comparison with other minimally invasive techniques. In addition, this review provides a step-by-step instruction guide on how to perform this procedure, including a multimedia tutorial to facilitate learning.

Association of time of day and extubation success in very low birthweight infants: a multicenter cohort study.

OBJECTIVE: To determine the association of overnight extubation (OE) with extubation success. STUDY DESIGN: Retrospective cohort study in three NICUs from 2016 to 2020. Infants without congenital anomalies, less than 1500 grams at birth, who were ventilated and received an extubation attempt were included. Primary exposure was OE (7:00 pm-6:59 am) and outcome was extubation success defined as no mechanical ventilation for at least 7 days after extubation. RESULTS: A total of 76/379 (20%) infants received OE. Infants extubated during the daytime were older and had higher illness severity markers. Extubation success rates did not differ for overnight (57/76, 75%) versus daytime extubations (231/303, 76%) after adjusting for confounders (adjusted relative risk 0.95, 95% CI 0.82-1.11). CONCLUSION: Though infants in our cohort undergoing daytime and OE were dissimilar, extubation success rates did not differ. Larger multicenter studies are needed to test our findings and identify markers of extubation readiness in preterm infants.

Alternative Methods of Surfactant Administration in Preterm Infants with Respiratory Distress Syndrome: State of the Art.

For preterm infants with respiratory distress syndrome, delivery of surfactant via brief intubation (INtubate, SURfactant, Extubate; InSurE) has been the standard technique of surfactant administration. However, this method requires intubation and positive pressure ventilation. It is thought that even the short exposure to positive pressure inflations may be enough to initiate the cascade of events that lead to lung injury in the smallest neonates. In an effort to avoid tracheal intubation and positive pressure ventilation, several alternative and less invasive techniques of exogenous surfactant administration have been developed over the years. These have been investigated in clinical studies, including randomized clinical trials, and have demonstrated advantages such as a decrease in the need for mechanical ventilation and incidence of bronchopulmonary dysplasia. These newer techniques of surfactant delivery also have the benefit of being easier to perform. Surfactant delivery via pharyngeal instillation, laryngeal mask, aerosolization, and placement of a thin catheter are being actively pursued in research. We present a contemporary review of surfactant administration for respiratory distress syndrome via these alternative methods in the hope of guiding physicians in their choices for surfactant application in the neonatal intensive care unit.

In Vitro CRISPR/Cas9-Directed Gene Editing to Model LRRK2 G2019S Parkinson's Disease in Common Marmosets.

Leucine-rich repeat kinase 2 (LRRK2) G2019S is a relatively common mutation, associated with 1-3% of Parkinson's disease (PD) cases worldwide. G2019S is hypothesized to increase LRRK2 kinase activity. Dopaminergic neurons derived from induced pluripotent stem cells of PD patients carrying LRRK2 G2019S are reported to have several phenotypes compared to wild type controls, including increased activated caspase-3 and reactive oxygen species (ROS), autophagy dysfunction, and simplification of neurites. The common marmoset is envisioned as a candidate nonhuman primate species for comprehensive modeling of genetic mutations. Here, we report our successful use of CRISPR/Cas9 with repair template-mediated homology directed repair to introduce the LRRK2 G2019S mutation, as well as a truncation of the LRRK2 kinase domain, into marmoset embryonic and induced pluripotent stem cells. We found that, similar to humans, marmoset LRRK2 G2019S resulted in elevated kinase activity. Phenotypic evaluation after dopaminergic differentiation demonstrated LRRK2 G2019S-mediated increased intracellular ROS, decreased neuronal viability, and reduced neurite complexity. Importantly, these phenotypes were not observed in clones with LRRK2 truncation. These results demonstrate the feasibility of inducing monogenic mutations in common marmosets and support the use of this species for generating a novel genetic-based model of PD that expresses physiological levels of LRRK2 G2019S.

Aerosolized Calfactant for Newborns With Respiratory Distress: A Randomized Trial.

BACKGROUND: Exogenous surfactants to treat respiratory distress syndrome (RDS) are approved for tracheal instillation only; this requires intubation, often followed by positive pressure ventilation to promote distribution. Aerosol delivery offers a safer alternative, but clinical studies have had mixed results. We hypothesized that efficient aerosolization of a surfactant with low viscosity, early in the course of RDS, could reduce the need for intubation and instillation of liquid surfactant. METHODS: A prospective, multicenter, randomized, unblinded comparison trial of aerosolized calfactant (Infasurf) in newborns with signs of RDS that required noninvasive respiratory support. Calfactant was aerosolized by using a Solarys nebulizer modified with a pacifier adapter; 6 mL/kg (210 mg phospholipid/kg body weight) were delivered directly into the mouth. Infants in the aerosol group received up to 3 treatments, at least 4 hours apart. Infants in the control group received usual care, determined by providers. Infants were intubated and given instilled surfactant for persistent or worsening respiratory distress, at their providers' discretion. RESULTS: Among 22 NICUs, 457 infants were enrolled; gestation 23 to 41 (median 33) weeks and birth weight 595 to 4802 (median 1960) grams. In total, 230 infants were randomly assigned to aerosol; 225 received 334 treatments, starting at a median of 5 hours. The rates of intubation for surfactant instillation were 26% in the aerosol group and 50% in the usual care group (P < .0001). Respiratory outcomes up to 28 days of age were no different. CONCLUSIONS: In newborns with early, mild to moderate respiratory distress, aerosolized calfactant at a dose of 210 mg phospholipid/kg body weight reduced intubation and surfactant instillation by nearly one-half.

α-Synuclein Expression Is Preserved in Substantia Nigra GABAergic Fibers of Young and Aged Neurotoxin-Treated Rhesus Monkeys.

α-Synuclein (α-syn) is a small presynaptic protein distributed ubiquitously in the central and peripheral nervous system. In normal conditions, α-syn is found in soluble form, while in Parkinson's disease (PD) it may phosphorylate, aggregate, and combine with other proteins to form Lewy bodies. The purpose of this study was to evaluate, in nonhuman primates, whether α-syn expression is affected by age and neurotoxin challenge. Young adult (n = 5, 5-10 years old) and aged (n = 4, 23-25 years old) rhesus monkeys received a single unilateral carotid artery injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Three months post-MPTP the animals were necropsied by transcardiac perfusion, and their brains extracted and processed with immunohistochemical methods. Quantification of tyrosine hydroxylase (TH)-positive substantia nigra (SN) neurons showed a significant 80-89% decrease in the side ipsilateral to MPTP administration in young and old animals. Optical density of TH- immunoreactivity (-ir) in the caudate and putamen presented a 60-70% loss compared with the contralateral side. α-Syn-ir was present in both ipsi- and contra- lateral MPTP-treated nigra, caudate, and putamen, mostly in fibers; its intracellular distribution was not affected by age. Comparison of α-syn-ir between MPTP-treated young and aged monkeys revealed significantly higher optical density for both the ipsi- and contralateral caudate and SN in the aged animals. TH and α-syn immunofluorescence confirmed the loss of nigral TH-ir dopaminergic neurons in the MPTP-treated side of intoxicated animals, but bilateral α-syn expression. Colabeling of GAD67 and α-syn immunofluorescence showed that α-syn expression was present mainly in GABAergic fibers. Our results demonstrate that, 3 months post unilateral intracarotid artery infusion of MPTP, α-syn expression in the SN is largely present in GABAergic fibers, regardless of age. Bilateral increase of α-syn expression in SN fibers of aged, compared with young rhesus monkeys, suggests that α-syn-ir may increase with age, but not after neurotoxin-induced dopaminergic nigral cell loss.

Estimating base cation weathering rates in the United States: challenges of uncertain soil mineralogy and specific surface area with applications of the PROFILE model.

The weathering release rate of base cations (BCw) from soil minerals is fundamentally important for terrestrial ecosystem growth, function, and sensitivity to acid deposition. Understanding BCw is necessary to reduce or prevent damage to acid-sensitive natural systems, in that this information is needed to both evaluate the effectiveness of existing policies, and guide establishment of further policies in the event they are required. Yet BCw is challenging to estimate. In this study, major sources of uncertainty associated with a process-based model (PROFILE) commonly used to estimate weathering rates were quantified in the context of efforts to quantify BCw for upland forest sites across the continental U.S. These include uncertainty associated with parameterization of mineral content where horizon data are not available, stoichiometry of individual minerals, and specific surface area of soil and individual soil minerals. Mineral stoichiometry was not an important influence on BCw estimates (uncertainty < 1%). Characterizing B horizon mineralogy by averaging A and C horizons was found to be a minor (< 5%) contributor to uncertainty in some areas, but where mineralogy is known to vary with depth the uncertainty can be large. Estimating mineral-specific surface areas had a strong influence on estimated BCw, with rates increasing by as much as 250%. The greatest uncertainty in BCw estimates, however, was attributed to the particle size class-based method used to estimate the total specific surface area upon which weathering reactions can take place. The resulting uncertainty in BCw spanned multiple orders of magnitude at individual sites, highlighting this as the greatest challenge to ongoing efforts to produce robust BCw estimates across large spatial scales in the U.S. Recommendations for improving estimates of BCw to support robust decision making for protection against terrestrial acidification are provided.

Utility of morbidity and mortality conference in end-of-life education in the neonatal intensive care unit.

BACKGROUND: A monthly neonatal intensive care unit (NICU) morbidity and mortality conference (M&MC) was used to study the documentation of end-of-life (EOL) care, and integrate related education for staff and trainees. OBJECTIVE: To study the current documentation of comprehensive, interdisciplinary, palliative EOL care in the NICU at the Vanderbilt Children's Hospital and improve it relative to a historical background. DESIGN/METHODS: A survey tool was developed and used at all neonatal M&MCs for 1 year (August 2003 through July 2004), in conducting a prospective chart audit of 50% of NICU deaths. The survey ascertained documentation of EOL care to include the anticipation of death by family and staff; provision of pain management; discussion of ethical and EOL decision-making issues; and the use of supportive services. Clinical education and literature references pertaining to these elements of care were presented in the conferences. RESULTS: Twenty-six surveys were completed (48% of deaths in NICU over the study period). Documentation of EOL care ranged from excellent (pain management, 100%) to poor (spiritual support, 54%). Documentation of all other measures varied from 69% to 92%. Staff and trainees reported educational enhancement of the M&MC, and greater awareness of issues important to EOL care throughout this period. CONCLUSIONS: Areas for improving EOL care exist in the NICU. The M&MC is a familiar venue for incorporating EOL care education for staff and trainees. A survey tool may serve to aid in the assessment of documentation of such care. Staff awareness of, and attention to, EOL issues may be improved through such a mechanism.

Induced Pluripotent Stem Cell-Derived Dopaminergic Neurons from Adult Common Marmoset Fibroblasts.

The common marmoset monkey (Callithrix jacchus; Cj) is an advantageous nonhuman primate species for modeling age-related disorders, including Parkinson's disease, due to their shorter life span compared to macaques. Cj-derived induced pluripotent stem cells (Cj-iPSCs) from somatic cells are needed for in vitro disease modeling and testing regenerative medicine approaches. Here we report the development of a novel Cj-iPSC line derived from adult marmoset fibroblasts. The Cj-iPSCs showed potent pluripotency properties, including the development of mesodermal lineages in tumors after injection to immunocompromised mice, as well as ectoderm and endoderm lineages after in vitro differentiation regimens, demonstrating differentiated derivatives of all three embryonic layers. In addition, expression of key pluripotency genes (ZFP42, PODXL, DNMT3B, C-MYC, LIN28, KLF4, NANOG, SOX2, and OCT4) was observed. We then tested the neural differentiation capacity and gene expression profiles of Cj-iPSCs and a marmoset embryonic stem cell line (Cj-ESC) after dual-SMAD inhibition. Exposure to CHIR99021 and sonic hedgehog (SHH) for 12 and 16 days, respectively, patterned the cells toward a ventralized midbrain dopaminergic phenotype, confirmed by expression of FOXA2, OTX2, EN-1, and tyrosine hydroxylase. These results demonstrate that common marmoset stem cells will be able to serve as a platform for investigating regenerative medicine approaches targeting the dopaminergic system.

Real-Time Intraoperative MRI Intracerebral Delivery of Induced Pluripotent Stem Cell-Derived Neurons.

Induced pluripotent stem cell (iPSC)-derived neurons represent an opportunity for cell replacement strategies for neurodegenerative disorders such as Parkinson's disease (PD). Improvement in cell graft targeting, distribution, and density can be key for disease modification. We have previously developed a trajectory guide system for real-time intraoperative magnetic resonance imaging (RT-IMRI) delivery of infusates, such as viral vector suspensions for gene therapy strategies. Intracerebral delivery of iPSC-derived neurons presents different challenges than viral vectors, including limited cell survival if cells are kept at room temperature for prolonged periods of time, precipitation and aggregation of cells in the cannula, and obstruction during injection, which must be solved for successful application of this delivery approach. To develop procedures suitable for RT-IMRI cell delivery, we first performed in vitro studies to tailor the delivery hardware (e.g., cannula) and defined a range of parameters to be applied (e.g., maximal time span allowable between cell loading in the system and intracerebral injection) to ensure cell survival. Then we performed an in vivo study to evaluate the feasibility of applying the system to nonhuman primates. Our results demonstrate that the RT-IMRI delivery system provides valuable guidance, monitoring, and visualization during intracerebral cell delivery that are compatible with cell survival.