In the field of regenerative medicine, biomaterials play a crucial role since they may serve as a support (scaffold) to promote cell growth and differentiation in order to promote the healing of tissue lesion. The aim of this chapter will be to analyze the properties of more recent biomaterials suitable for tissue engineering strategies, to end to define better and innovative materials for scaffold production. To this purpose, we will analyze the main materials (natural and synthetic) and their characteristics, such as biocompatibility, bioactivity, and biodegradation, and it will be discussed how their chemical-physical properties (surface morphology, porosity, stiffness, and mechanical strength) could affect the interaction with cells and living system. Moreover, the chapter will be focused on methods of extraction or production of biomaterial suitable for scaffolds.

The management of chondral defects represents a big challenge because of the limited self-healing capacity of cartilage. Many approaches in this field obtained partial satisfactory results. Cartilage tissue engineering, combining innovative scaffolds and stem cells from different sources, emerges as a promising strategy for cartilage regeneration. The aim of this study was to evaluate the capability of a cell-free collagen I-based scaffold to promote cartilaginous repair after orthotopic implantation in vivo. Articular cartilage lesions (ACL) were created at the femoropatellar groove in rat knees and cell free collagen I-based scaffolds (S) were then implanted into right knee defect for the ACL-S group. No scaffold was implanted for the ACL group. At 4-, 8- and 16-weeks post-transplantation, degrees of cartilage repair were evaluated by morphological, histochemical and gene expression analyses. Histological analysis shows the formation of fibrous tissue, at 4-weeks replaced by a tissue resembling the calcified one at 16-weeks in the ACL group. In the ACL-S group, progressive replacement of the scaffold with the newly formed cartilage-like tissue is shown, as confirmed by Alcian Blue staining. Immunohistochemical and quantitative real-time PCR (qRT-PCR) analyses display the expression of typical cartilage markers, such as collagen type I and II (ColI and ColII), Aggrecan and Sox9. The results of this study display that the collagen I-based scaffold is highly biocompatible and able to recruit host cells from the surrounding joint tissues to promote cartilaginous repair of articular defects, suggesting its use as a potential approach for cartilage tissue regeneration.

In recent years, microRNAs (miRNAs) have received increasing attention for their important role in tumor initiation and progression. MiRNAs are a class of endogenous small non-coding RNAs that negatively regulate the expression of several oncogenes or tumor suppressor genes. MiR-19a, a component of the oncogenic miR-17-92 cluster, has been reported to be highly expressed only in anaplastic thyroid cancer, the most undifferentiated, aggressive and lethal form of thyroid neoplasia. In this work, we evaluated the putative contribution of miR-19a in de-differentiation and aggressiveness of thyroid tumors. To this aim, we induced miR-19a expression in the well-differentiated follicular thyroid cancer cell line and evaluated proliferation, apoptosis and gene expression profile of cancer cells. Our results showed that miR-19a overexpression stimulates cell proliferation and alters the expression profile of genes related to thyroid cell differentiation and aggressiveness. These findings not only suggest that miR-19a has a possible involvement in de-differentiation and malignancy, but also that it could represent an important prognostic indicator and a good therapeutic target for the most aggressive thyroid cancer.

Background: MicroRNAs (miRNAs) are endogenous, single-stranded, non-coding RNAs acting as negative regulators of gene expression involved in a number of physiological processes. MiRNAs' expression is commonly dysregulated in many types of human tumor diseases and cancers, including thyroid cancers, and is often involved in tumor initiation and progression. miR-19a, a member of miR-17-92 cluster, has been demonstrated to promote cell growth in anaplastic thyroid cancer (ATC), the most advanced and aggressive thyroid cancer. Purpose: In this work, we investigate the potential contribution of miR-19a in thyroid cancer cells poor prognosis and de-differentiation. Methods: We directly modulated the expression of miR-19a in papillary (PTC) and anaplastic thyroid carcinoma cell lines through transfection of specific miR-19a mimic or inhibitor. Further, we performed gene expression analysis of specific genes to evaluate miR-19a association with cell cycle, differentiation, and poor prognosis. Results: Our data indicate that miR-19a overexpression in PTC cells significantly promotes cell growth, decreases the expression of differentiation genes and activates poor prognosis genes. Its inhibition in ATC cells reduces cell proliferation and the expression of genes related to poor prognosis but does not affect differentiation. Conclusion: Our findings reveal the existence of functional associations between miR-19a expression and thyroid cancer progression and malignancy suggesting miR-19a as a novel candidate therapeutic target for ATC.

Osteoarthritis (OA) is a complex disease, source of pain and disability that affects millions of people worldwide. OA etiology is complex, multifactorial and joint-specific, with genetic, biological and biomechanical components. Recently, several studies have suggested a potential adjuvant role for natural extracts on OA progression, in terms of moderating chondrocyte inflammation and following cartilage injury, thus resulting in an overall improvement of joint pain. In this study, we first analyzed the phenylethanoid glycosides profile and the total amount of polyphenols present in a leaf aqueous extract of Verbascum thapsus L. We then investigated the anti-inflammatory and anti-osteoarthritic bioactive potential of the extract in murine monocyte/macrophage-like cells (RAW 264.7) and in human chondrocyte cells (HC), by gene expression analysis of specifics inflammatory cytokines, pro-inflammatory enzymes and metalloproteases. Six phenylethanoid glycosides were identified and the total phenolic content was 124.0 ± 0.7 mg gallic acid equivalent (GAE)/g of extract. The biological investigation showed that the extract is able to significantly decrease most of the cellular inflammatory markers, compared to both control cells and cells treated with Harpagophytum procumbens (Burch.) DC. ex Meisn, used as a positive control. Verbascum thapsus leaf aqueous extract has the potential to moderate the inflammatory response, representing an innovative possible approach for the inflammatory joint disease treatment.