RESUMO
Aim To investigate whether human umbili-cal cord mesenchymal stem cells(hUC-MSCs)exposed to inflammatory conditions could release large amounts of exosomes to induce regulatory T cells(Treg).Meth-ods hUC-MSCs were isolated by enzyme digestion method.(In vitro)interferonγ(IFN-γ)was added in-to hUC-MSCs to mimic inflammatory microenviron-ments,then exosomes were extracted from the superna-tant of normal conditional medium or IFN-γpretreated hUC-MSCs.Both sources of exosomes,Nor-hUC-exo and IFN-γ-stimulated hUC-exo, were identified by Nanoparticle Trafficking Analysis (NTA )and Western blot for the exosome-enriched protein CD63 .Next,hu-man peripheral blood mononuclear cells (PBMCs ) stimulated with PHA were respectively co-cultured with hUC-MSCs,IFN-γ-pretreated-hUC-MSCs,hUC-MSCs exosomes or IFN-γ-stimulated-hUC-MSCs exosomes for 5 days to assess the exosomes-T cells communication. The proliferation rate of PBMCs and frequency of CD4 +/CD25 +/Foxp3 + Treg were measured by flow cytometry.Results The isolated cells from human um-bilical cord tissue,which were positive for CD73, CD44,CD29,CD90 and HLA-ABC,but were nega-tive for CD31 and CD34,were mesenchymal stem cells indeed.After IFN-γtreatment,hUC-MSCs secreted nu-merous exosomes(P<0.05 ).Morerover,there was a significantly higher level of CD63 ,but no difference in diameter between Nor-hUC-exo and IFN-γ-stimulated hUC-exo.IFN-γ-stimulated hUC-exo had a superior a-bility compared with Nor-hUC-exo to suppress the pro-liferation of PHA stimulated PBMCs due to their upreg-ulation of the percentage of Treg (1 1.53 ±0.88% vs 6.60 ±0.56%,P <0.01 ).Conclusion hUC-MSCs could promote the expression of Treg to modulate im-munosuppression through exosomes,especially for IFN-γ-licenced exosomes,which might carry much immu-notherapeutic potential.
RESUMO
Objective To compare dual-energy X-ray absorptiometry T-score concordance between hip and lumbar spine, and to estimate the value of T-score of the hip for diagnosing osteoporosis in the elderly. Methods From September 2000 to May 2002, 123 males aged 60-89 years (average 72.0?7.4) and 137 females aged 60-88 years (average 67.3?6.1) were selected in the study based on the exclusion of subjects with apparent abnormalities affecting bone mass or taking medications which might affect bone metabolism. Detailed questionnaire included lifestyle factors such as smoking, drinking, exercise and dietary habits, etc. Radiographs of the thoracic and lumbar spine were taken. Patients' BMD were measured by DEXA (DMS, Challenger) at lumbar spine (L 2-4) and left hip in posterior-anterior projection. The right hip was scanned if patients had a history of fractures or any bone disease in the left hip. All data were statistically analysed using SPSS 8.0 system. Results The average T-scores of bone mineral density of the lumbar spine were higher than that of the hip in all male patients and in 65-, 85- age groups of female patients(P