Fetal metabolic adaptations to cardiovascular stress in twin-twin transfusion syndrome.

Monochorionic-diamniotic twin pregnancies are susceptible to unique complications arising from a single placenta shared by two fetuses. Twin-twin transfusion syndrome (TTTS) is a constellation of disturbances caused by unequal blood flow within the shared placenta giving rise to a major hemodynamic imbalance between the twins. Here, we applied TTTS as a model to uncover fetal metabolic adaptations to cardiovascular stress. We compared untargeted metabolomic analyses of amniotic fluid samples from severe TTTS cases vs. singleton controls. Amniotic fluid metabolites demonstrated alterations in fatty acid, glucose, and steroid hormone metabolism in TTTS. Among TTTS cases, unsupervised principal component analysis revealed two distinct clusters of disease defined by levels of glucose metabolites, amino acids, urea, and redox status. Our results suggest that the human fetal heart can adapt to hemodynamic stress by modulating its glucose metabolism and identify potential differences in the ability of individual fetuses to respond to cardiovascular stress.

Cryopreserved human umbilical cord as a meningeal patch during in utero spina bifida repair in a modified ovine model.

OBJECTIVE: Despite in utero spina bifida (SB) repair, more than two-thirds of patients with SB are unable to ambulate independently, and 1 in 4 children need surgery for tethered cord by school age. The objective of this study was to test the cryopreserved human umbilical cord (HUC) as an antiscarring material to reduce tethering and improve function in a modified in utero SB repair model. METHODS: An SB defect (L2-6 levels) without myelotomy was created in fetuses of timed-pregnant ewes at gestational day (GD) 75. On GD 96, the fetal defect was exposed, and the arachnoid layer was removed to disrupt the barrier and expose the spinal cord to simulate human in utero SB repair. The fetuses were randomly assigned to two groups according to the method used to cover the spinal cord: the conventional repair (CR) group, for which myofascial closure was used (n = 7), and the HUC meningeal patch group, for which HUC was used as a meningeal patch (n = 6), followed by primary skin closure. The lambs were delivered at GD 140. Blinded clinical assessment of spinal cord function was performed using the Texas Spinal Cord Injury Scale (TSCIS). Histology of the spine was performed for quantitative assessment of spinal cord tethering, inflammatory markers, and arachnoid layer regeneration. RESULTS: The TSCIS scores were significantly lower in the CR than the HUC meningeal patch group (p = 0.0015) and the controls (p = 0.0018). The loss of spinal cord function in the CR group was mainly due to ataxia and loss of proprioception (p = 0.01 and 0.005 vs control and HUC, respectively). The histology at the repair site showed higher rates of spinal cord tethering in the CR lambs than the HUC lambs at all levels of the repair site (p = 0.01 and 0.02 vs control and HUC, respectively). In the CR with tethering compared with the HUC repair, there was a lower arachnoid layer covering at the repair site (p = 0.001). There was greater astrocyte activation in the posterior column in the CR than in the HUC repair group (p = 0.01). CONCLUSIONS: In a modified ovine SB model, the HUC as a meningeal patch allows regeneration of the arachnoid layer, prevents spinal cord tethering, and improves spinal cord function after in utero SB repair.

Steroid Hormone Levels in Recipient Amniotic Fluid in Twin-Twin Transfusion Syndrome and Their Association with Preterm Delivery.

OBJECTIVE: Preterm delivery following fetoscopic laser surgery (FLS) of twin-twin transfusion syndrome (TTTS) is associated with severe perinatal morbidity and mortality. The role of steroid hormones in amniotic fluid (AF) after FLS remains unknown. STUDY DESIGN: A prospective cohort study of consecutive case series of FLS for TTTS was performed from April 2012 to February 2017. Cases were divided into early (≤27 weeks) spontaneous preterm delivery (ED) and late delivery (LD; ≥34 weeks) following FLS and compared. AF supernatants were assessed for protein, estradiol, progesterone and cortisol levels (using the ELISA kit), and normalized to total protein levels to adjust for dilution. RESULTS: A total of 294 consecutive cases of FLS for TTTS in monochorionic-diamniotic twins were performed during the study period. AF was available in 44 ED patients and 50 LD patients. On logistic regression, ED was associated with higher normalized progesterone levels (odds ratio [OR]: 1.25; 95% confidence interval [CI]: 1.12-1.41), lower normalized cortisol (OR: 0.78; 95% CI: 0.64-0.96), and higher estradiol levels (OR: 1.3; 95% CI: 1.03-1.63). CONCLUSION: Elevated AF normalized progesterone and estradiol, and lower normalized cortisol levels were associated with ED. This novel finding requires further exploration to establish the molecular mechanism operational in pregnancies complicated by TTTS to potentially prevent early preterm birth after fetal surgery.

Surgical management of lipomas: Proposal of the Z-incision design and surgical algorithm based on tumor size.

Surgical excision is the treatment of choice for lipomas. However, linear incision methods or minimal extraction techniques often do not provide a sufficient surgical view. Therefore, removing large lipomas is often difficult. To present the Z-incision and half Z-incision designs for lipoma extraction, this retrospective study analyzed lipomas surgically excised at our institution between September 2015 and December 2018. The area of surgical field exposed by the Z-incision versus that exposed by the linear incision was calculated using a schematic model. Cure rate, complications, and surgical field area were investigated. A total of 84 lipomas were included. A Z- or half Z-incision was used to treat 30 lipomas, while a linear incision was used to treat 54 lipomas. The mean diameter of the mass in the Z- or half Z-incision group was 47.7 mm (range, 15-160 mm), larger than that in the linear incision group (25.5 mm; range, 7-59 mm) (p < .001). The Z-incision involved making rectangular windows by lifting 2 triangular flaps. According to our mathematical model, the Z-incision provided a larger surgical field area than that provided by the linear incision based on stretched angles (1.81 times larger at 30° and 3.14 times larger at 15°). The Z- and half Z-incisions were successfully performed in all but 1 lipoma (29 lipomas, 96.7%). There was 1 lipoma that resulted in postoperative complications (seroma, 3.3%). The Z-incision design can be a useful alternative technique for the extirpation of lipomas, especially large lipomas. Here, we proposed a surgical algorithm for lipoma surgery based on tumor size.

Cryopreserved human umbilical cord versus acellular dermal matrix patches for in utero fetal spina bifida repair in a pregnant rat model.

OBJECTIVE: Despite significant improvement in spinal cord function after in utero spina bifida (SB) repair compared with traditional postnatal repair, over half of the children who undergo this procedure do not benefit completely. This lack of benefit has been attributed to closure methods of the defect, with subsequent spinal cord tethering at the repair site. Hence, a regenerative patch or material with antiinflammatory and anti-scarring properties may alleviate comorbidities with improved outcomes. The authors' primary objective was therefore to compare cryopreserved human umbilical cord (HUC) versus acellular dermal matrix (ADM) patches for regenerative repair of in utero SB lesions in an animal model. METHODS: In vivo studies were conducted in retinoic acid-induced SB defects in fetuses of Sprague-Dawley rats. HUC or ADM patches were sutured over the SB defects at a gestational age of 20 days. Repaired SB defect tissues were harvested after 48-52 hours. Tissue sections were immunofluorescently stained for the presence of neutrophils, macrophages, keratinocytes, meningeal cells, and astrocytes and for any associated apoptosis. In vitro meningeal or keratinocyte cell coculture experiments with the ADM and HUC patches were performed. All experiments were scored quantitatively in a blinded manner. RESULTS: Neutrophil counts and apoptotic cells were lower in the HUC-based repair group (n = 8) than in the ADM patch repair group (n = 7). In the HUC patch repair group, keratinocytes were present on the outer surface of the patch, meningeal cells were present on the inner surface of the patch adjacent to the neural placode, and astrocytes were noted to be absent. In the ADM patch repair group, all 3 cell types were present on both surfaces of the patch. In vitro studies showed that human meningeal cells grew preferentially on the mesenchymal side of the HUC patch, whereas keratinocytes showed tropism for the epithelial side, suggesting an inherent HUC-based cell polarity. In contrast, the ADM patch studies showed no polarity and decreased cellular infiltration. CONCLUSIONS: The HUC patch demonstrated reduced acute inflammation and apoptosis together with superior organization in regenerative cellular growth when compared with the ADM patch, and is therefore likely the better patch material for in utero SB defect repair. These properties may make the HUC biomaterial useful as a "meningeal patch" during spinal cord surgeries, thereby potentially reducing tethering and improving on spinal cord function.

Active and stable carbon nanotube/nanoparticle composite electrocatalyst for oxygen reduction.

Nanostructured carbon-based materials, such as nitrogen-doped carbon nanotube arrays, Co3O4/nitrogen-doped graphene hybrids and carbon nanotube-graphene complexes have shown respectable oxygen reduction reaction activity in alkaline media. Although certainly promising, the performance of these materials does not yet warrant implementation in the energy conversion/storage devices utilizing basic electrolytes, for example, alkaline fuel cells, metal-air batteries and certain electrolysers. Here we demonstrate a new type of nitrogen-doped carbon nanotube/nanoparticle composite oxygen reduction reaction electrocatalyst obtained from iron acetate as an iron precursor and from cyanamide as a nitrogen and carbon nanotube precursor in a simple, scalable and single-step method. The composite has the highest oxygen reduction reaction activity in alkaline media of any non-precious metal catalysts. When used at a sufficiently high loading, this catalyst also outperforms the most active platinum-based catalysts.

Genome editing of human embryonic stem cells and induced pluripotent stem cells with zinc finger nucleases for cellular imaging.

RATIONALE: Molecular imaging has proven to be a vital tool in the characterization of stem cell behavior in vivo. However, the integration of reporter genes has typically relied on random integration, a method that is associated with unwanted insertional mutagenesis and positional effects on transgene expression. OBJECTIVE: To address this barrier, we used genome editing with zinc finger nuclease (ZFN) technology to integrate reporter genes into a safe harbor gene locus (PPP1R12C, also known as AAVS1) in the genome of human embryonic stem cells and human induced pluripotent stem cells for molecular imaging. METHODS AND RESULTS: We used ZFN technology to integrate a construct containing monomeric red fluorescent protein, firefly luciferase, and herpes simplex virus thymidine kinase reporter genes driven by a constitutive ubiquitin promoter into a safe harbor locus for fluorescence imaging, bioluminescence imaging, and positron emission tomography imaging, respectively. High efficiency of ZFN-mediated targeted integration was achieved in both human embryonic stem cells and induced pluripotent stem cells. ZFN-edited cells maintained both pluripotency and long-term reporter gene expression. Functionally, we successfully tracked the survival of ZFN-edited human embryonic stem cells and their differentiated cardiomyocytes and endothelial cells in murine models, demonstrating the use of ZFN-edited cells for preclinical studies in regenerative medicine. CONCLUSION: Our study demonstrates a novel application of ZFN technology to the targeted genetic engineering of human pluripotent stem cells and their progeny for molecular imaging in vitro and in vivo.