Conversion Rate in Pediatric Robotic-Assisted Surgery: Looking for the Culprit.

Introduction: Robotic-assisted surgery (RAS) is increasingly used in adulthood but its application in pediatric population is limited. We report our initial experience in pediatric RAS, focusing on conversions to analyze their causes. Methods: All pediatric patients who underwent RAS between June 2015 and April 2019 were included, analyzing demographics, comorbidities, previous surgery, and intraoperative surgical and anesthetic parameters. A three-arms robotic technique was used in all cases. Additional laparoscopic ports were added, when needed. The surgical team did not change during the program, whereas the anesthesiology team varied. Results: Thirty-nine patients (23 females, 16 males; mean age ± SD = 9.33 ± 4.73 years [range = 1-16]; mean weight ± SD = 35.2 ± 20.0 kg [range = 9-85]) underwent 40 different procedures (18 gastrointestinal, 15 urogynecological, 5 oncological, and 2 miscellaneous). Three procedures (7.5%) were converted to open surgery for inadequate working space (two marked bowel distension and one insufficient hepatic retraction). Converted patients were of significant lower age (mean ± standard error of mean [SEM] = 2.97 ± 1.03 versus 9.83 ± 0.77 years, P = .01) and lower weight (mean ± SEM = 11.83 ± 1.74 versus 35.47 ± 3.16 kg, P = .03). The two groups did not differ statistically for duration of facial mask ventilation before intubation (mean ± SEM = converted 10.67 ± 2.33 versus completed 10.31 ± 0.91 minutes), neuromuscular block dosage (rocuronium; mean ± SEM = converted 0.46 ± 0.06 mg/kg versus completed 0.62 ± 0.03 mg/kg) and in the type of bowel preparation (mechanical and/or pharmacological). Discussion: Conversion rate in initial pediatric RAS program is acceptable. In children, the need for conversion is mainly because of inadequate working space, particularly in smaller children, but it seems not to be influenced by measurable anesthetic factors or different regimen for bowel preparation.

Adenosine A1 receptor stimulation enhances osteogenic differentiation of human dental pulp-derived mesenchymal stem cells via WNT signaling.

In this study, mesenchymal stem cells deriving from dental pulp (DPSCs) of normal human impacted third molars, previously characterized for their ability to differentiate into osteoblasts, were used. We observed that: i) DPSCs, undifferentiated or submitted to osteogenic differentiation, express all four subtypes of adenosine receptors (AR) and CD73, corresponding to 5'-ecto-nucleotidase; and ii) AR stimulation with selective agonists elicited a greater osteogenic cell differentiation consequent to A1 receptor (A1R) activation. Therefore, we focused on the activity of this AR. The addition of 15-60nM 2-chloro-N(6)-cyclopentyl-adenosine (CCPA), A1R agonist, to DPSCs at each change of the culture medium significantly increased the proliferation of cells grown in osteogenic medium after 8days in vitro (DIV) without modifying that of undifferentiated DPSCs. Better characterizing the effect of A1R stimulation on the osteogenic differentiation capability of these cells, we found that CCPA increased the: i) expression of two well known and early osteogenic markers, RUNX-2 and alkaline phosphatase (ALP), after 3 and 7DIV; ii) ALP enzyme activity at 7DIV and iii) mineralization of extracellular matrix after 21DIV. These effects, abolished by cell pre-treatment with the A1R antagonist 8-cyclopentyl-1,3-dipropyl-xanthine (DPCPX), involved the activation of the canonical Wnt signaling as, in differentiating DPSCs, CCPA significantly increased dishevelled protein and inhibited glycogen synthase kinase-3ß, both molecules being downstream of Wnt receptor signal pathway. Either siRNA of dishevelled or cell pre-treatment with Dickkopf-1, known inhibitor of Wnt signaling substantially reduced either DPSC osteogenic differentiation or its enhancement promoted by CCPA. Summarizing, our findings indicate that the stimulation of A1R may stimulate DPSC duplication enhancing their osteogenic differentiation efficiency. These effects may have clinical implications possibly facilitating bone tissue repair and remodeling.

Wnt signaling behaves as a "master regulator" in the osteogenic and adipogenic commitment of human amniotic fluid mesenchymal stem cells.

Human amniotic fluid mesenchymal stem cells (huAFMSCs) are emerging as a promising therapeutic option in regenerative medicine. Here, we characterized huAFMSC phenotype and multipotentiality. When cultured in osteogenic medium, huAFMSC displayed a significant increase in: Alkaline Phosphatase (ALP) activity and mRNA expression, Alizarin Red S staining and Runx2 mRNA expression; whereas maintaining these cells in an adipogenic culture medium gave a time-dependent increase in PPARγ and FABP4 mRNA expression, glycerol-3-phosphate dehydrogenase (GPDH) activity and positivity to Oil Red Oil staining. These results confirm that huAFMSCs can differentiate toward osteogenic and adipogenic phenotypes. The canonical Wnt/ßcatenin signaling pathway appears to trigger huAFMSC osteoblastogenesis, since during early phases of osteogenic differentiation, the expression of Dishevelled-2 (Dvl-2), of the non-phosphorylated form of ß-catenin, and the phosphorylation of glycogen synthase kinase-3ß (GSK3ß) at serine 9 were upregulated. On the contrary, during adipogenic differentiation Dvl-2 expression decreased, whereas that of ß-catenin remained unchanged. This was associated with a late increase in GSK3ß phosphorylation. Consistent with this scenario, huAFMSCs exposure to Dickkopf-1, a selective inhibitor of the Wnt signaling, abolished Runx2 and ALP mRNA upregulation during huAFMSC osteogenic differentiation, whereas it enhanced FABP4 expression in adipocyte-differentiating cells. Taken together, these results unravel novel molecular determinants of huAFMSC commitment towards osteoblastogenesis, which may represent potential targets for directing the differentiation of these cells and improving their use in regenerative medicine.