Sternal Repair with Bone Grafts Engineered from Amniotic Mesenchymal Stem Cells

Background We aimed at determining whether osseous grafts engineered from amniotic mesenchymal stem cells (aMSCs) could be employed in postnatal sternal repair. Methods Leporine aMSCs were isolated, identified, transfected with green fluorescent protein (GFP), expanded, and seeded onto biodegradable electrospun nanofibrous scaffolds (n=6). Constructs were dynamically maintained in an osteogenic medium and equally divided into two groups with respect to time in vitro, namely 14.6 or 33.9 weeks. They were then used to repair full thickness sternal defects spanning 2–3 intercostal spaces in allogeneic kits (n=6). Grafts were submitted to multiple analyses 2 months thereafter. Results Chest roentgenograms showed defect closure in all animals, confirmed at necropsy. Graft density as assessed by micro-CT scans increased significantly in vivo, yet there were no differences in mineralization by extracellular calcium measurements pre- and post-implantation. There was a borderline increase in alkaline phosphatase activity in vivo, suggesting ongoing graft remodeling. Histologically, implants contained GFP-positive cells and few mononuclear infiltrates. There were no differences between the two construct groups in any comparison. Conclusions Engineered osseous grafts derived from amniotic mesenchymal stem cells may become a viable alternative for sternal repair. The amniotic fluid can be a practical cell source for engineered chest wall reconstruction

Intra-amniotic delivery of amniotic-derived neural stem cells in a syngeneic model of spina bifida.

OBJECTIVE: Neural stem cells (NSCs) may promote spinal cord repair in fetuses with experimental spina bifida. We sought to determine the fate of amniotic-derived NSCs (aNSCs) after simple intra-amniotic injection in a syngeneic model of spina bifida. METHODS: Fetal neural tube defects were induced on 20 pregnant Lewis dams by prenatal administration of retinoic acid. Ten dams served as amniotic fluid donors for epigenetic isolation of aNSCs, which were expanded and labeled with 5-bromo-2\u27-deoxyuridine. The remaining 10 dams received intra-amniotic injections of the processed aNSCs, blindly in all their fetuses (n = 37) on gestational day 17 (term = E21-22). Fetuses with spina bifida underwent screening for the presence of donor aNSCs in the spinal cord at term. RESULTS: Donor cells were identified in 93.3% of the animals with spina bifida, selectively populating the neural placode, typically in clusters, retaining an undifferentiated morphology, and predominantly on exposed neural surfaces, though some were detected deeper in neighboring neural tissue. CONCLUSIONS: The amniotic cavity can serve as a route of administration of NSCs in experimental spina bifida. Simple intra-amniotic delivery of NSCs may be a practical adjuvant to regenerative strategies for the treatment of spina bifida

Pediatric postoperative intussusception in the minimally invasive surgery era: a 13-year, single center experience.

BACKGROUND: Postoperative intussusception (POI) is a sporadic complication whose mechanisms and risk factors remain poorly understood. Its epidemiology in the minimally invasive surgery era has yet to be well described, particularly in children. We sought to examine risk factors, demographics, and anatomic patterns of pediatric POI in recent years. STUDY DESIGN: This was a 13-year retrospective review from a single tertiary pediatric center. Variables analyzed included patient demographics, time of occurrence, type of intussusception, type of anesthesia, and triggering surgical procedure. The latter variable was divided into 2 groups: abdominal and nonabdominal interventions. Statistical analysis was by 2-tailed Fisher\u27s exact test with significance set at p \u3c 0.05. RESULTS: Among 822 cases of intussusception in 718 patients, 22 documented cases of POI were identified. Twelve of them occurred after abdominal procedures; there was a statistically significant difference in the incidence of POI after open surgery (0.091%; 11 of 12,126) when compared with minimally invasive interventions (0.013%; 1 of 7,610; p = 0.036). As expected, ileoileal and jejunojejunal intussusceptions were the most common forms of POI after abdominal operations (12 of 12; 100%); however, ileocolic intussusceptions were common forms of POI after nonabdominal cases (5 of 10; 50%; p = 0.01). Epidural anesthesia did not appear to be a risk factor for POI. CONCLUSIONS: Although rare, postoperative intussusception can occur after a multitude of interventions, including those performed at a distance from the abdomen. Although small bowel intussusception is the predominant variant of this complication after abdominal procedures, ileocolic intussusception is prevalent after other interventions. Minimally invasive abdominal access may protect against postoperative intussusception in children

The amniotic fluid as a source of neural stem cells in the setting of experimental neural tube defects.

We sought to determine whether neural stem cells (NSCs) can be isolated from the amniotic fluid in the setting of neural tube defects (NTDs), as a prerequisite for eventual autologous perinatal therapies. Pregnant Sprague-Dawley dams (n=62) were divided into experimental (n=42) and control (n=20) groups, depending on prenatal exposure to retinoic acid for the induction of fetal NTDs. Animals were killed before term for analysis (n=685 fetuses). Amniotic fluid samples from both groups underwent epigenetic selection for NSCs, followed by exposure to neural differentiation media. Representative cell samples underwent multiple morphological and phenotypical analyses at different time points. No control fetus (n=267) had any structural abnormality, whereas at least one type of NTD developed in 52% (217/418) of the experimental fetuses (namely, isolated spina bifida, n=144; isolated exencephaly, n=24; or a combination of the two, n=49). Only amniotic samples from fetuses with a NTD yielded cells with typical neural progenitor morphology and robust expression of both Nestin and Sox-2, primary markers of NSCs. These cells responded to differentiation media by displaying typical morphological changes, along with expression of beta-tubulin III, glial fibrillary acidic protein, and/or O4, markers for immature neurons, astrocytes, and oligodendrocytes, respectively. This was concurrent with downregulation of Nestin and Sox-2. We conclude that the amniotic fluid can harbor disease-specific stem cells, for example, NSCs in the setting of experimental NTDs. The amniotic fluid may be a practical source of autologous NSCs applicable to novel forms of therapies for spina bifida