Regulatory authorities and orthopaedic clinical trials on expanded mesenchymal stem cells.

Skeletal injuries requiring bone augmentation techniques are increasing in the context of avoiding or treating difficult cases with bone defects, bone healing problems, and bone regeneration limitations. Musculoskeletal severe trauma, osteoporosis-related fractures, and conditions where bone defect, bone collapse or insufficient bone regeneration occur are prone to disability and serious complications. Bone cell therapy has emerged as a promising technique to augment and promote bone regeneration. Interest in the orthopaedic community is considerable, although many aspects related to the research of this technique in specific indications may be insufficiently recognised by many orthopaedic surgeons. Clinical trials are the ultimate research in real patients that may confirm or refute the value of this new therapy. However, before launching the required trials in bone cell therapy towards bone regeneration, preclinical data is needed with the cell product to be implanted in patients to ensure safety and efficacy. These preclinical studies support the end-points that need to be evaluated in clinical trials. Orthopaedic surgeons are the ultimate players that, through their research, would confirm in clinical trials the benefit of bone cell therapies. To further foster this research, the pathway to eventually obtain authorisation from the National Competent Authorities and Research Ethics Committees under the European regulation is reviewed, and the experience of the REBORNE European project offers information and important clues about the current Voluntary Harmonization Procedure and other opportunities that need to be considered by surgeons and researchers on the topic.

Bone regeneration: stem cell therapies and clinical studies in orthopaedics and traumatology.

Regenerative medicine seeks to repair or replace damaged tissues or organs, with the goal to fully restore structure and function without the formation of scar tissue. Cell based therapies are promising new therapeutic approaches in regenerative medicine. By using mesenchymal stem cells, good results have been reported for bone engineering in a number of clinical studies, most of them investigator initiated trials with limited scope with respect to controls and outcome. With the implementation of a new regulatory framework for advanced therapeutic medicinal products, the stage is set to improve both the characterization of the cells and combination products, and pave the way for improved controlled and well-designed clinical trials. The incorporation of more personalized medicine approaches, including the use of biomarkers to identify the proper patients and the responders to treatment, will be contributing to progress in the field. Both translational and clinical research will move the boundaries in the field of regenerative medicine, and a coordinated effort will provide the clinical breakthroughs, particularly in the many applications of bone engineering.

Tumour-associated fibroblasts and mesenchymal stem cells: more similarities than differences.

Tumour-associated fibroblasts (TAFs) are part of the tumour stroma, providing functional and structural support for tumour progression and development. The origin and biology of TAFs are poorly understood, but within the tumour environment, TAFs become activated and secrete different paracrine and autocrine factors involved in tumorigenesis. It has been shown that bone marrow mesenchymal stem cells (MSCs) can be recruited into the tumours, where they proliferate and acquire a TAF-like phenotype. We attempted to determine to what extent TAFs characteristics in vitro juxtapose to MSCs' definition, and we showed that TAFs and MSCs share immunophenotypic similarities, including the presence of certain cell surface molecules [human leukocyte antigen-DR subregion (HLA-DR), CD29, CD44, CD73, CD90, CD106 and CD117]; the expression of cytoskeleton and extracellular matrix proteins, such as vimentin, α-smooth muscle actin, nestin and trilineage differentiation potential (to adipocytes, chondrocytes and osteoblasts). When compared to MSCs, production of cytokines, chemokines and growth factors showed a significant increase in TAFs for vascular endothelial growth factor, transforming growth factor-ß1, interleukins (IL-4, IL-10) and tumour necrosis factor α. Proliferation rate was highly increased in TAFs and fibroblast cell lines used in our study, compared to MSCs, whereas ultrastructural details differentiated the two cell types by the presence of cytoplasmic elongations, lamellar content lysosomes and intermediate filaments. Our results provide supportive evidence to the fact that TAFs derive from MSCs and could be a subset of 'specialized' MSCs.

In vitro differentiation of human mesenchymal stem cells to epithelial lineage.

Our study examined whether human bone marrow-derived MSCs are able to differentiate, in vitro, into functional epithelial-like cells. MSCs were isolated from the sternum of 8 patients with different hematological disorders. The surface phenotype of these cells was characterized.To induce epithelial differentiation, MSCs were cultured using Epidermal Growth Factor, Keratinocyte Growth Factor, Hepatocyte Growth Factor and Insulin-like growth Factor-II. Differentiated cells were further characterized both morphologically and functionally by their capacity to express markers with specificity for epithelial lineage. The expression of cytokeratin 19 was assessed by immunocytochemistry, and cytokeratin 18 was evaluated by quantitative RT-PCR (Taq-man). The data demonstrate that human MSCs isolated from human bone marrow can differentiate into epithelial-like cells and may thus serve as a cell source for tissue engineering and cell therapy of epithelial tissue.

[Experimental model of in vitro generation of human dendritic cells]. / Obtinerea si cultivarea celulelor dendritice umane in vitro. Model experimental.

INTRODUCTION: Dendritic cells (DCs) are considered the most powerful antigen-presenting cells (APC) playing a strategic role in triggering the immune response. Monocytes are the physiological precursors of myeloid DCs. AIMS: This paper aims to develop an in vitro experimental model of human dendritic cells generation and phenotypic and functional analysis starting from CD14+ monocyte precursors isolated from peripheral blood. MATERIALS AND METHODS: CD14+ monocytes were isolated from venous peripheral blood which was harvested from consenting healthy donors. By the means of GM-CSF and IL-4 immature DCs were generated from monocytes. In the sixth day we added TNF-alpha and PGE-2 maturation factors and, after 48 hours we harvested mature DCs. Their morphology was monitored by optical microscopy, while the phenotypes were determined by flow cytometry. RESULTS: After three days of culture, the monocytes developed a specific morphology, gathering in clusters; cells presenting specific features start to detach in the sixth day. Treatment with TNF-alpha and PGE-2 induces the maturation of DCs and up-regulation of CD80, CD83 and CD86 expressions. Phenotypic analysis of mature DCs was HLA-DR+++/CD86- CD80+++/CD14(-)/CD11a+/CD83+++. DCs obtained are able to stimulate in vivo allolymphocyte capacity. Functional analysis test showed 87% CD4+ CFSE+(DCs+PBMC) cells vs CD4+ CFSE+(PBMC) 15% cells. CONCLUSIONS: This experiment developed an effective and viable way to generate DCs from PBMCs exposed to GM-CSF and IL-4. The cells obtained presented morphological, phenotypic and functional features as DCs described in the literature.

[Characteristics of bronchial inflammation in children with chronic non-productive cough]. / Caracteristicile inflamatiei bronsice la copiii cu tuse cronica neproductiva.

The aim of study was to correlate the bronchoalveolar lavage (BAL) cell subpopulations in light microscopy and clinical-functional parameters in 20 children with chronic nonproductive cough (potentially evolving to asthma) in comparison with 20 children with mild and moderate stable asthma. The results revealed a different BAL cell profile of chronic coughing children, characterized by a lower percent of total cells (0.279 +/- 0.055 x 10(6)/ml), eosinophils (0.97 +/- 0.80%), lymphocytes (6.02 +/- 0.85%) and epithelial cells (28.52 +/- 5.15%) and higher percent of macrophages (46.05 +/- 7.94%) and neutrophils (18.27 +/- 4.93%). Eosinophilic inflammation in BAL and bronchial hyper-responsiveness (PC20 methacholine = 1.73 +/- 0.15 mg/ml) were revealed in three cases with chronic cough. Based on these reasons, they were included in "cough variant asthma". In conclusion, children with nonproductive chronic cough represent a heterogenous group, with different underlying causes. Only a minority of these patients has "cough variant asthma", with a favorable response to inhaled corticotherapy.

Endothelial cells from hematopoietic stem cells are functionally different from those of human umbilical vein.

Hematopoietic stem cells have a remarkable plastic capacity, which allows them to differentiate into various cells, such as immune cells, nervous cells, muscle cells, bone and cartilaginous cells. The aim of this study was to show the capacity of stem cells to differentiate into endothelial cells, in culture, after addition of endothelial cells growth supplement (ECGS). We also compared the behavior of these cells with that of endothelial cells obtained from human umbilical vein (HUVEC). CD34+ cells obtained by immunomagnetic separation from human umbilical cord and placental blood were used. After 12-15 days of culture in a medium containing ECGS, the cells showed morphological changes characteristic to endothelial cells and immunocytochemical analysis revealed the presence of CD31 surface antigen and von Willebrand factor. The flow-cytometric analysis of endothelial cells adhesion molecules (ECAM) showed that endothelial cells derived from CD34+ cells expressed CD54/ICAM-1 9.65+/-0.2% and CD106/VCAM 7.73+/-0.3%, values similar to those expressed by HUVECs. After TNF incubation, ECAM expression increased only in HUVECs. These data demonstrate that a fraction of circulating CD34+ cells may develop some endothelial cell characteristics when cultured with ECGS, but they are functionally different from HUVECs.