The effect of polyethylenglycol gel on the delivery and osteogenic differentiation of homologous tooth germ-derived stem cells in a porcine model.

OBJECTIVES: The aim of this study was to investigate if bone regeneration can be promoted by homologous transplantation of STRO-1 sorted (STRO-1+) porcine tooth germ mesenchymal stem cells (TGSCs) with the combination of polyethylenglycol (PEG)-based hydrogel and biphasic calcium phosphate (BCP) scaffolds. MATERIAL AND METHODS: TGSCs were isolated from impacted third molars of domestic pigs. Nine critical-sized defects were created as (1) untreated defect; filled with (2) autogenous bone; (3) BCP + PEG; (4) BCP + PEG + unsorted TGSCs; (5) BCP + unsorted TGSCs; (6) BCP + PEG + STRO-1-sorted TGSCs; (7) BCP + STRO-1-sorted TGSCs; (8) BCP + PEG + osteogenic induced unsorted TGSCs; and (9) BCP + PEG + osteogenic induced STRO-1-sorted TGSCs in 20 domestic pigs. CM-DiI labelling was used to track cells in vivo. Histomorphometric assessment of new bone formation was achieved by toluidine blue O staining and microradiography after 1, 2, 4 and 12 weeks posttransplantation. RESULTS: Complete healing was achieved in all defects although defects with PEG hydrogel presented better bone formation while STRO-1+ and unsorted TGSCs showed similar ability to form new bone after 12 weeks. Transplanted cells were seen in defects where PEG hydrogel was used as carriers in contrast to defects treated with cells and only bone grafts. CONCLUSIONS: PEG hydrogel is an efficient carrier for homologous stem cell transplantation. TGSCs are capable of promoting bone healing in critical-sized defects in combination with bone graft and PEG hydrogel. CLINICAL RELEVANCE: This study provides information about the importance of the delivery vehicle for future translational stem cell delivery approaches.

Stigma and suicidality among suicide attempt survivors: A qualitative study.

Among people with mental illness, stigma experiences can increase suicidality, and suicidality itself is associated with negative stereotypes. Suicide attempt survivors experience both mental illness stigma and suicide stigma, which could contribute to their increased risk for completed suicide. We interviewed 13 suicide attempt survivors regarding experiences and consequences of stigma and identified five stigma-related themes. Stigma led to substantial emotional strain, including loneliness and hopelessness, which are important precursors of suicidality. Our findings suggest that both mental illness stigma and suicide stigma can contribute to suicidality among people with mental illness in general, and in suicide attempt survivors specifically.

Mismatch response in preterm and asphyxic neonates: a functional electrophysiological investigation of attention and habituation.

BACKGROUND AND AIM: There is a lack of diagnostic tools for early risk stratification of cognitive outcome in infants born preterm and infants with asphyxia. Using auditory event-related potentials and mismatch response, we aimed to assess possible differences in early attention and learning, as a marker for brain maturation to subsequently improve the allocation of early neurodevelopmental support. STUDY DESIGN AND METHODS: This cross-sectional study included 22 very preterm infants (gestational age (GA) < 32 weeks), eight term infants with asphyxia and 35 healthy term infants. An auditory oddball-paradigm with three consecutive stimulation blocks, separated by a two-minute break, was used as a cognitive discrimination task to assess attention and habituation. RESULTS: The peak-to-peak analysis in the group comparisons showed no significant differences for the first stimulation block. In term healthy infants and term infants after asphyxia, no significant differences were found in amplitudes between block one and three. Preterm infants showed significantly (p = .007) lower amplitudes in the third block for F7 congruent to a positive habituation. The amplitude of the grouped electrodes correlated positively with GA for frontal (R = .271, p= .029) and parietal electrodes (R =.275, p = .027). CONCLUSION: We found no differences in the auditory attention paradigm between preterm or term asphyxic and control infants when they were evaluated at term corrected age. Most infants did not show any electrophysiologically measurable learning effect indicating habituation or dishabituation. The small sample size of this study is a clear limitation. Therefore, the results must be evaluated with caution, especially regarding their potential predictive value for future cognitive development of infants with a developmental risk. However, our study underlines the possibility of an electrophysiological evaluation as a feasible tool to assess very early cognition in infants.

Predicting neurodevelopmental outcome in preterm born infants using auditory event-related potentials: A systematic review.

Prematurity is a known risk factor for later cognitive deficits. At present there are neither behavioral nor neurological tests available to detect those preterm infants who would benefit most from early interventions. Neurophysiologic methods, and more specifically, auditory event-related potentials (AERPs) are convenient tools to investigate early cognitive functioning. However, the capability of AERPs as a prognostic factor for mental development in preterm infants remains unclear. The present systematic search of the literature yielded 1016 articles, out of which 13 were included. Both prospective and cross-sectional studies reported a relationship between AERPs and cognitive outcome. Our results show that larger amplitudes and shorter latencies of late AERPs are related to better cognitive outcomes. Additional studies are needed to corroborate our findings regarding this potential use of AERPs in the individual evaluation of preterm born infants.