IGF1 and IGF1/VEGF cross-talk on human mesenchymal stromal cells (hMSCs): the role of stem cell sources in bone healing

Repair of skeletal defects remains a considerable biomedical problem. One of the major obstacles of the different tested strategies still remains the vascularization of engineered scaffolds. To this aim we have examined the ability of IGF1, alone or in association with VEGF, to modulate Periosteum Derived Progenitor Cells (PDPCs) (Ferretti et al., 2012) and Skin-Mesenchymal Stromal Cells (S-MSCs) (Orciani and Di Primio, 2013) osteoblastic or endothelial commitment. A selected gene panel for endothelial and osteoblastic differentiation as well as genes that can affect MAPK and PI3K/AKT signalling pathways were investigated. Our results showed a different commitment of PDPCs and S-MSCs under growth factor stimulation: the former are induced towards an osteoblastic differentiation, whilst the latter seem to be brought to an endothelial phenotype. This commitment is also related to a diverse MAPK or PI3K/AKT signalling pathway activation. Our results open intriguing perspective for the development of innovative bone tissue engineering approaches based on associated angiogenesis and osteogenesis. Further investigations are however necessary to gain insight on the real cross-talk between proliferation and differentiation in adult stem cells. The work was supported by Italian FIRB (RBAP10MLK7) and PRIN (2010J8RYS7) project grants

The role of the mesenchymal stem cells on breast cancer: friends or foes?

Mesenchymal stem cells (MSCs) have been the subject of an increased interest. Because of their ability to give rise to bone, cartilage, fat and muscle, their role in regenerative medicine has been extensively studied and the fact that they can be recruited at sites of inflammation and tissue repair has prompted their potential use as tissue regenerative cells. Contextually there has been a growing interest in the role of MSCs in cancer progression. The nature of the relationship between MSCs and tumor cells appears dual, with effects pro- as well as anti-tumorigenic. This paradox depends on the source and the degree of differentiation of MSCs and the tumor model used. Moreover, with the large range of cytokines and growth factors they produce, MSCs exert regulatory function on apoptosis, angiogenesis and an immunomodulatory role. Here we evaluate the interaction between MSCs derived from the periprosthetic capsule of mastectomyzed women and the breast cancer cell line MCF-7. Capsular tissue around breast implants is a normal inflammatory reaction versus a foreign body and it is rich of MSCs. To asses how MSCs interact with tumor cells, MCF-7 cells were incubated with medium previously conditioned by MSCs or directly co-coltured with MSCs; subsequently, we evaluated the proliferation and the expression of genes implicated in different pathways (angiogenesis, proliferation, anti-apoptosis, EMT transition). Our results showed that MCF-7 cells cultured together MSCs or using their conditioned medium have a more elevated proliferation rate but tumour cells seem less aggressive, like attested by a reduction of the expression of selected genes. The understanding of the mechanisms that control the interaction between MSCs and tumor cells is still at an early stage but recent literature confirm that MSCs and their progeny are not innocent bystanders in the tumor microenvironment. The study of these interactions is a critical area of future investigation that is needed to better define their role in cancer progression and their potential as therapeutic agents or targets

Periosteal derived cells and bone tissue regenerative medicine

Mesenchymal stem cells (MSCs), showing a high capacity of self-renewal and differentiation into various lineages, have primarily used for the biological repair of cartilage and bone. Even though MSCs have been identified in different organ tissues, cells from different sources may show phenotypic heterogeneity, different in vivo results and specific functions of graft regions after transplantation. Therefore, a correct selection of MSC source is crucial to obtain a more efficient treatment for regeneration of injured osteochondral tissues. Periosteum Derived Progenitor Cells (PDPCs), which possesses multipotency at single cell level and can form cartilage and bone in vitro and in vivo may represent as an interesting cell resource for bone tissue engineering. Aim of the present study is the isolation and characterization of human PDPCs and the evaluation of their ability to grow on bioresorbable composite scaffolds for bone tissue engineering applications. PDCPs were obtained from periosteal tissue harvested from healthy subjects undergoing surgery for orthopedic trauma. Prior to cells seeding cell were phenotipically characterized. Three composite scaffolds, differing in weight ratios between the components were tested. The scaffolds were coded as CEL2/POL 0/100, 40/60 and 70/30 where CEL2 is a bioglass and POL the organic component based on chitosan and gelatin. Cells were cultured for 14 and 21 days. Our culture conditions favour the selection of a mesenchymal stem cells population. The obtained PDPCs displayed a good ability to interact with the different tested scaffolds. Morphological and biochemical analysis performed showed that cells maintain their metabolic activity and ability to proliferate on the scaffolds. Differentiation over proliferation that occurred to PDCPs at the increase of bioactive glass concentration proves the capacity of these scaffolds to modulate osteogenic properties. This strengthens the hypothesis of periosteum as stem cell source for an osteochondral tissue regenerative medicine based on in situ cell recruitment. This work was supported by RBAP10MLK7 FIRB project

matricellular protein expression and cell ultrastructure as parameters to test in vitro cytotoxicity of a biomimetic scaffold

Following scaffold implantation, cell sufferance, in-vivo encapsulation, foreign body reaction and inflammatory response has been reported and the up- regulation of matricellular proteins is often connected with this condition. Cytotoxicity of biomaterials is generally tested according to ISO standard 10993-5 based mainly on viability tests. Additional assays, based on improved cytotoxicity knowledge, are suggested in order to better analyze the biocompatibility of implant materials. The purpose of the study was to evaluate the matricellular protein expression as biomarker for in vitro-testing the biocompatibility of implant materials. Tenascin-C, osteocalcin and osteopontin belong to the matricellular protein family and were chosen as cytotoxicity markers. Mesenchymal stem cells were seeded on collagen/hydroxyapatite scaffold and on carboxymethyl cellulose based hydrogel in order to evaluate gene/protein expression by cell viability test, Real Time PCR and western blot. Electron microscopy was carried out to evaluate the morphological changes induced by cell/scaffold interactions. A low expression of tenascin-c, osteonectin and osteopontin was demonstrated in collagen/hydroxyapatite scaffold compared to the cells cultured on tissue flasks and on hydrogel scaffold. Based on our results, we propose matricellular protein expression as parameter for testing in vitro biocompatibility of implant materials

Effectiveness and Safety of Transthoracic Ultrasound in Guiding Percutaneous Needle Biopsy in the Lung and Comparison vs. CT Scan in Assessing Morphology of Subpleural Consolidations

(1) Background: The aim of this study was to conduct a prospective analysis on the diagnostic accuracy of transthoracic ultrasound-guided percutaneous needle biopsy (TUS-PNB) for the histological assessment of peripheral lung lesions and to assess the performance of transthoracic ultrasound (TUS) examination vs. chest CT (gold standard) in the differentiation between malignant and benign peripheral lung lesions. (2) Methods: A total of 961 consecutive patients with subpleural pulmonary lesions were enrolled. All the patients received a CT scan with contrast; 762 patients underwent TUS-PTNB for suspicion of malignancy, and the remaining 199 enrolled patients underwent only TUS examination as a part of routine follow-up for known non-malignant subpleural consolidations. (3) Results: Among the 762 TUS-guided biopsies, there were 627 (82.28%) malignant lesions, 82 (10.76%) benign lesions, and 53 (6.96%) indeterminate lesions. The overall diagnostic accuracy was 93.04%. The rates of pneumothorax not requiring chest-tube insertion and self-limited hemoptysis were 0.79 and 0.26%, respectively. Patients were divided into two groups based on the benign or malignant nature of the subpleural consolidations. On TUS, both malignant and benign lesions showed mostly irregular margins and a hypoechoic pattern, but no differences were assessed in terms of sonographic margins and pattern between the two groups. There was poor agreement between TUS and chest CT in assessing air bronchograms and necrotic areas. The only finding in the detection of which TUS showed superiority compared to chest-CT was pleural effusion. (4) Conclusions: TUS-PNB was confirmed to be an effective and safe diagnostic method for peripheral pulmonary consolidation, but their sonographic pattern did not allow to rule out a malignant nature. A pre-operative evaluation on CT images, combined with the possibility of performing additional immunohistochemical and cytological investigations and the experience of the medical staff, may improve the diagnostic yield of TUS-guided biopsies

Elotuzumab plus pomalidomide and dexamethasone in relapsed/refractory multiple myeloma: a multicenter, retrospective real-world experience with 200 cases outside of controlled clinical trials

In the ELOQUENT-3 trial, the combination of elotuzumab, pomalidomide and dexamethasone (EloPd) proved a superior clinical benefit over Pd with a manageable toxicity profile, leading to its approval in relapsed/refractory multiple myeloma (RRMM), who had received at least two prior therapies, including lenalidomide and a proteasome inhibitor (PI). We report here a real-world experience of 200 RRMMs treated with EloPd in 35 Italian centers outside of clinical trials. In our dataset, the median number of prior lines of therapy was 2, with 51% of cases undergoing autologous stem cell transplant (ASCT) and 73% exposed to daratumumab. After a median follow-up of 9 months, 126 patients stopped EloPd, most of them (88.9%) because of disease progression. The overall response rate (ORR) was 55.4%, in line with the pivotal trial results. Regarding adverse events, our cohort experienced a toxicity profile similar to the ELOQUENT-3 trial, with no significant differences between younger (<70 years) and older patients. The median progression-free survival (PFS) was 7 months, shorter than that observed in the ELOQUENT-3, probably due to the different clinical characteristics of the two cohorts. Interestingly, the ISS stage III (HR:2.55) was associated with worse PFS. Finally, our series's median overall survival (OS) was shorter than that observed in the ELOQUENT-3 trial (17.5 versus 29.8 months). In conclusion, our real-world study confirms EloPd as a safe and possible therapeutic choice for RRMM who received at least two prior therapies, including lenalidomide and a PI

Periosteum derived stem cells for regenerative medicine proposals: boosting current knowledge

Periosteum is a thin fibrous layer that covers most bones. It resides in a dynamic mechanically loaded environment and provides a niche for pluripotent cells and a source for molecular factors that modulate cell behaviour. Elucidating periosteum regenerative potential has become a hot topic in orthopaedics. This review discusses the state of the art of osteochondral tissue engineering rested on periosteum derived progenitor cells (PDPCs) and suggests upcoming research directions. Periosteal cells isolation, characterization and migration in the site of injury, as well as their differentiation, are analysed. Moreover, the role of cell mechanosensing and its contribution to matrix organization, bone microarchitecture and bone stenght is examined. In this regard the role of periostin and its upregulation under mechanical stress in order to preserve PDPC survival and bone tissue integrity is contemplated. The review also summarized the role of the periosteum in the field of dentistry and maxillofacial reconstruction. The involvement of microRNAs in osteoblast differentiation and in endogenous tissue repair is explored as well. Finally the novel concept of a guided bone regeneration based on the use of periosteum itself as a smart material and the realization of constructs able to mimic the extracellular matrix features is talked out. Additionally, since periosteum can differentiate into insulin producing cells it could be a suitable source in allogenic transplantations. That innovative applications would take advantage from investigations aimed to assess PDPC immune privilege

Nanoparticle-mediated delivery of IL-2 to T follicular helper cells protects BDF1 mice from lupus-like disease

We recently reported that poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) loaded with interleukin (IL)-2 and targeted to T cells inhibited the development of lupus-like disease in BDF1 mice by inducing functional T regulatory cells (Tregs). Here we show that the protection from disease and the extended survival of BDF1 mice provided by IL-2-loaded NPs targeted to T cells is not only due to an induction of Tregs but also contributed by an inhibition of T follicular helper (T(FH)) cells. These results identify a dual protective activity of IL-2 in the control of lupus autoimmunity, namely the inhibition of effector T(FH) cells, in addition to the previously known induction of Tregs. This newly recognized activity of IL-2 delivered by NPs can help better explain the beneficial effects of low-dose IL-2 immunotherapy in systemic lupus erythematosus (SLE), and might be considered as a new strategy to slow disease progression and improve outcomes in lupus patients