Lung imaging in bronchopulmonary dysplasia: a systematic review.

BACKGROUND: Bronchopulmonary dysplasia (BPD) remains a common complication of preterm birth. Both historically and in current practice, radiologic evaluation of the lungs has an important role in assessing disease severity and complications. AIM: To provide an overview of imaging techniques for detecting lung abnormalities in patients with BPD in all age ranges. METHODS: A systematic literature search was conducted in PubMed, Web of Science and the Cochrane Library. Records were screened by title and abstract and then by full text. A total of 37 records were selected and included in this qualitative literature overview. RESULTS: Computed tomography (CT) was the most commonly used imaging modality, followed by chest radiography and magnetic resonance imaging (MRI). Several qualitative and quantitative scoring systems were presented and most showed good correlation with BPD severity. The association with functional and clinical outcomes was only rarely reported, showing varying correlation with spirometry results and respiratory exacerbations. MRI is an upcoming imaging technique for BPD that is technically feasible, showing clear differences in the lung parenchyma of patients with BPD. CONCLUSION: Several imaging and scoring methods indicate that lung imaging continues to play a role in BPD care. Standardization and correlation with functional and clinical outcomes will become increasingly important for further research.

Sleep-disordered breathing and pulmonary function in obese children and adolescents.

OBJECTIVE: Obese children have an increased risk of developing obstructive sleep apnea syndrome (OSAS) compared to normal-weight children. In obese children, OSAS is more frequently associated with oxygen desaturations, which might be caused by pulmonary function abnormalities. Our goal was to investigate the association between OSAS and pulmonary function in obese children and adolescents. METHODS: There were 185 children included and distributed in groups based on their obstructive apnea-hypopnea index (151 controls, 20 mild OSAS, and 14 moderate-to-severe OSAS). All subjects underwent polysomnography and pulmonary function testing. RESULTS: Several differences in pulmonary function were observed between groups. Vital capacity (VC) and forced expired volume in 1s (FEV1) were significantly decreased in patients with moderate-to-severe OSAS, as were expiratory reserve volume (ERV), total lung capacity, and functional residual capacity (FRC). Correlations between FEV1, FRC, and ERV with OSAS severity remained significant independent of the degree of adiposity. Correlations between FEV1/VC and sleep-related respiratory parameters did not persist after correction for adiposity. CONCLUSION: An association between awake pulmonary function and sleep-related respiratory parameters could be observed in our population of obese children. These results suggest that OSAS severity is correlated with a diminished lung function. However, the level of obesity remains an important confounding factor in both OSAS severity and pulmonary function.

Endothelial cells are essential for ovarian stromal tissue restructuring after xenotransplantation of isolated ovarian stromal cells.

BACKGROUND: Grafting of isolated follicles represents an approach to prevent the risk of reimplanting malignant cells with cryopreserved ovarian fragments. Optimal conditions and cell types required to sustain human follicular growth need to be identified. To help improve the grafting technique, we investigated whether short-term xenografting of a suspension containing ovarian stromal and endothelial cells without follicles could enhance graft survival and revascularization. METHODS: In human ovary, CD34 selectively labels endothelial cells of blood vessels. A CD34-replete ovarian stromal cell group, including stromal and endothelial cells, was obtained after enzymatic digestion of fresh human ovarian cortex. Magnetic-activated cell sorting was used to establish a CD34-depleted ovarian stromal cell group. Proportions of CD34-positive cells were evaluated by flow cytometry and immunocytochemistry. Cell suspensions were embedded in human plasma clots and grafted (n = 10 for each group, 7 days) to the ovarian bursa of nude mice. Angiogenesis was quantified after human/mouse CD34 immunostaining. RESULTS: CD34-replete grafts had a well-organized and vascularized stromal structure, containing tubular components staining for human CD34 and corresponding to functional vessels, as evidenced by intraluminal red blood cells. CD34-depleted grafts tended to be smaller than CD34-replete grafts and poorly vascularized with central necrosis. Global microvessel density was higher in the CD34-replete than depleted group (337.9 versus 187.3 vessels/mm(2), P < 0.05), with a greater proportion of human vessels (68.02 versus 6.95%, respectively, P < 0.05). CONCLUSIONS: We demonstrated the importance of co-transplanting ovarian endothelial and stromal cells to ensure the formation of a well-vascularized and structured ovarian-like stroma after short-term xenografting, for future application in the transplantation of isolated follicles.

Xenotransplantation of human ovarian tissue to nude mice: comparison between four grafting sites.

BACKGROUND: This study was designed to assess the impact of different ovarian tissue transplantation sites on the follicular pool and ovarian tissue integrity after short-term grafting, since there is no consensus in the literature as to the optimal grafting site in experimental models. METHODS: Frozen-thawed ovarian tissue from eight patients was grafted for 1 or 3 weeks to the peritoneum, inside the ovarian bursa, under the skin and into the muscle of 16 nude mice. Assessment of follicular density and follicle classification was carried out by histological analysis. Proliferative activity was evidenced by immunostaining with anti-Ki-67 antibodies, and fibrotic areas were analyzed by morphometry on histological slides. RESULTS: One week post-transplantation, the proportion of Ki-67-positive primordial follicles was higher (20-42%) than in controls (1.7%), demonstrating follicular activation in all four sites. Despite this activation, primordial follicles were still found 3 weeks post-grafting, (34.1-66.9% of the follicle population), most of them quiescent, as indicated by the absence of Ki-67 immunostaining. Cryopreservation and grafting resulted in extensive fibrosis in the stroma. This fibrosis was significantly less pronounced in intramuscular (IM) grafts, representing 18.8% of the surface versus 44.7-60.5% for other sites, after 3 weeks of grafting. CONCLUSIONS: All four grafting sites equally supported early follicular growth and preserved some quiescent follicles after short-term frozen-thawed human ovarian tissue transplantation. The extensive fibrosis observed does not appear to have a major impact on early follicle development, but its long-term effects must be investigated. The graft environment may be implicated in the preservation of the stroma, as suggested by a lower degree of fibrosis in the IM site.