Placental Mesenchymal Stromal Cells: Preclinical Safety Evaluation for Fetal Myelomeningocele Repair.

BackgroundMyelomeningocele (MMC) is the congenital failure of neural tube closure in utero, for which the standard of care is prenatal surgical repair. We developed clinical-grade placental mesenchymal stromal cells seeded on a dural extracellular matrix (PMSC-ECM), which have been shown to improve motor outcomes in preclinical ovine models. To evaluate the long-term safety of this product prior to use in a clinical trial, we conducted safety testing in a murine model.MethodsClinical grade PMSCs obtained from donor human placentas were seeded onto a 6 mm diameter ECM at a density of 3 × 105 cells/cm2. Immunodeficient mice were randomized to receive either an ECM only or PMSC-ECM administered into a subcutaneous pocket. Mice were monitored for tumor formation until two study endpoints: 4 wk and 6 mo. Pathology and histology on all tissues was performed to evaluate for tumors. Quantitative polymerase chain reaction (qPCR) was performed to evaluate for the presence of human DNA, which would indicate persistence of PMSCs.ResultsFifty-four mice were included; 13 received ECM only and 14 received PMSC-ECM in both the 4-wk and 6-mo groups. No mice had gross or microscopic evidence of tumor development. A nodular focus of mature fibrous connective tissue was identified at the subcutaneous implantation pocket in the majority of mice with no significant difference between ECM only and PMSC-ECM groups (P = 0.32 at 4 wk, P > 0.99 at 6 mo). Additionally, no human DNA was detected by qPCR in any mice at either time point.ConclusionsSubcutaneous implantation of the PMSC-ECM product did not result in tumor formation and we found no evidence that PMSCs persisted. These results support the safety of the PMSC-ECM product for use in a Phase 1/2a human clinical trial evaluating fetal MMC repair augmented with PMSC-ECM

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

PurposeAugmentation 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.MethodsLaminectomy 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.ResultsMRIs 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.ConclusionThere 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 evidenceN/A TYPE OF STUDY: Basic science

Efficacy of clinical-grade human placental mesenchymal stromal cells in fetal ovine myelomeningocele repair.

BackgroundWhile fetal repair of myelomeningocele (MMC) revolutionized management, many children are still unable to walk independently. Preclinical studies demonstrated that research-grade placental mesenchymal stromal cells (PMSCs) prevent paralysis in fetal ovine MMC, however this had not been replicated with clinical-grade cells that could be used in an upcoming human clinical trial. We tested clinical-grade PMSCs seeded on an extracellular matrix (PMSC-ECM) in the gold standard fetal ovine model of MMC.MethodsThirty-five ovine fetuses underwent MMC defect creation at a median of 76 days gestational age, and defect repair at 101 days gestational age with application of clinical-grade PMSC-ECM (3 × 105 cells/cm2, n = 12 fetuses), research-grade PMSC-ECM (3 × 105 cells/cm2, three cell lines with n = 6 (Group 1), n = 6 (Group 2), and n = 3 (Group 3) fetuses, respectively) or ECM without PMSCs (n = 8 fetuses). Three normal lambs underwent no surgical interventions. The primary outcome was motor function measured by the Sheep Locomotor Rating scale (SLR, range 0: complete paralysis to 15: normal ambulation) at 24 h of life. Correlation of lumbar spine large neuron density with SLR was evaluated.ResultsClinical-grade PMSC-ECM lambs had significantly better motor function than ECM-only lambs (SLR 14.5 vs. 6.5, p = 0.04) and were similar to normal lambs (14.5 vs. 15, p = 0.2) and research-grade PMSC-ECM lambs (Group 1: 14.5 vs. 15, p = 0.63; Group 2: 14.5 vs. 14.5, p = 0.86; Group 3: 14.5 vs. 15, p = 0.50). Lumbar spine large neuron density was strongly correlated with motor function (r = 0.753, p<0.001).ConclusionsClinical-grade placental mesenchymal stromal cells seeded on an extracellular matrix rescued ambulation in a fetal ovine myelomeningocele model. Lumbar spine large neuron density correlated with motor function, suggesting a neuroprotective effect of the PMSC-ECM in prevention of paralysis. A first-in-human clinical trial of PMSCs in human fetal myelomeningocele repair is underway

The impact of race and socioeconomic status on the presentation, management and outcomes for gastric cancer patients: Analysis from a metropolitan area in the southeast United States

Socioeconomic disparities in gastric cancer have been associated with differences in care and inferior outcomes. We evaluated the presentation, treatment, and survival for patients with gastric cancer (GC) in a metropolitan setting with a large African American population. Retrospective cohort analysis of patients with GC (2003-2018) across a multi-hospital system was performed. Associations between socioeconomic and clinicopathologic data with the presentation, treatment, and survival were examined. Of 359 patients, 255 (71%) were African American and 104 (29%) Caucasian. African Americans were more likely to present at a younger age (64.0 vs 72.5, P < .001), have state-sponsored or no insurance (19.7% vs 6.9%, P = .02), reside within the lowest 2 quintiles for median income (67.4% vs 32.7%, P < .001), and have higher rates of Helicobacter pylori (14.9% vs 4.8%, P = .02). Receipt of multi-modality therapy was not impacted by race or insurance status. On multivariable analysis, only AJCC T class (HR 1.68) and node positivity (HR 2.43) remained significant predictors of disease-specific survival. Despite socioeconomic disparities, African Americans, and Caucasians with GC had similar treatment and outcomes. African Americans presented at a younger age with higher rates of H. pylori positivity, warranting further investigation into differences in risk factors and tumor biology

In utero treatment of myelomeningocele with placental mesenchymal stromal cells - Selection of an optimal cell line in preparation for clinical trials.

BackgroundWe determined whether in vitro potency assays inform which placental mesenchymal stromal cell (PMSC) lines produce high rates of ambulation following in utero treatment of myelomeningocele in an ovine model.MethodsPMSC lines were created following explant culture of three early-gestation human placentas. In vitro neuroprotection was assessed with a neuronal apoptosis model. In vivo, myelomeningocele defects were created in 28 fetuses and repaired with PMSCs at 3 × 105 cells/cm2 of scaffold from Line A (n = 6), Line B (n = 7) and Line C (n = 5) and compared to no PMSCs (n = 10). Ambulation was scored as ≥13 on the Sheep Locomotor Rating Scale.ResultsIn vitro, Line A and B had higher neuroprotective capability than no PMSCs (1.7 and 1.8 respectively vs 1, p = 0.02, ANOVA). In vivo, Line A and B had higher large neuron densities than no PMSCs (25.2 and 27.9 respectively vs 4.8, p = 0.03, ANOVA). Line C did not have higher neuroprotection or larger neuron density than no PMSCs. In vivo, Line A and B had ambulation rates of 83% and 71%, respectively, compared to 60% with Line C and 20% with no PMSCs.ConclusionThe in vitro neuroprotection assay will facilitate selection of optimal PMSC lines for clinical use.Level of evidencen/a.Type of studyBasic science

Early investigations into improving bowel and bladder function in fetal ovine myelomeningocele repair.

IntroductionFetal myelomeningocele (MMC) repair improves lower extremity motor function. We have previously demonstrated that augmentation of fetal MMC repair with placental mesenchymal stromal cells (PMSCs) seeded on extracellular matrix (PMSC-ECM) further improves motor function in the ovine model. However, little progress has been made in improving bowel and bladder function, with many patients suffering from neurogenic bowel and bladder. We hypothesized that fetal MMC repair with PMSC-ECM would also improve bowel and bladder function.MethodsMMC defects were surgically created in twelve ovine fetuses at median gestational age (GA) 73 days, followed by defect repair at GA101 with PMSC-ECM. Fetuses were delivered at GA141. Primary bladder function outcomes were voiding posture and void volumes. Primary bowel function outcome was anorectal manometry findings including resting anal pressure and presence of rectoanal inhibitory reflex (RAIR). Secondary outcomes were anorectal and bladder detrusor muscle thickness. PMSC-ECM lambs were compared to normal lambs (n&nbsp;=&nbsp;3).ResultsEighty percent of PMSC-ECM lambs displayed normal voiding posture compared to 100% of normal lambs (p&nbsp;=&nbsp;1). Void volumes were similar (PMSC-ECM 6.1&nbsp;ml/kg vs. normal 8.8&nbsp;ml/kg, p&nbsp;=&nbsp;0.4). Resting mean anal pressures were similar between cohorts (27.0&nbsp;mmHg PMSC-ECM vs. normal 23.5&nbsp;mmHg, p&nbsp;=&nbsp;0.57). RAIR was present in 3/5 PMSC-ECM lambs that underwent anorectal manometry and all normal lambs (p&nbsp;=&nbsp;0.46). Thicknesses of anal sphincter complex, rectal wall muscles, and bladder detrusor muscles were similar between cohorts.ConclusionOvine fetal MMC repair augmented with PMSC-ECM results in near-normal bowel and bladder function. Further work is needed to evaluate these outcomes in human patients