Synthesis and Characterization of a new Alginate-Gelatine Aerogel for Tissue Engineering.

Scaffolds have been used to stimulate cell migration, cell adhesion, and cell proliferation as extracellular matrix analogues. This study proposes a novel method for creating hybrid alginate-gelatine aerogel-based scaffold, which could be suitable for cell adhesion. To this end, alginate-gelatine at 4% was first used to make stable hydrogels, which were then frozen at -70°C and dried under a vacuum to produced aerogels. Aerogels are materials known for their extremely low density, which, by definition, should be lower than 0.5 g/cm3, In this study, a bulk density of 0.16 g/cm3 was reached, confirming that the created material fits within the definition of an aerogel. In addition, the material presented a sponge-like structure, high absorption properties, and high-porosity, with an average pore size of 193µm. These properties fit within the requirements for fibroblast cell infiltrate and survival, demonstrating that the proposed alginate-gelatine aerogels are suitable candidates for various applications such as tissue engineering and regenerative medicine.

Printability of Double Network Alginate-Based Hydrogel for 3D Bio-Printed Complex Structures.

Three-dimensional (3D) bio-printing has recently emerged as a crucial technology in tissue engineering, yet there are still challenges in selecting materials to obtain good print quality. Therefore, it is essential to study the influence of the chosen material (i.e., bio-ink) and the printing parameters on the final result. The "printability" of a bio-ink indicates its suitability for bio-printing. Hydrogels are a great choice because of their biocompatibility, but their printability is crucial for exploiting their properties and ensuring high printing accuracy. However, the printing settings are seldom addressed when printing hydrogels. In this context, this study explored the printability of double network (DN) hydrogels, from printing lines (1D structures) to lattices (2D structures) and 3D tubular structures, with a focus on printing accuracy. The DN hydrogel has two entangled cross-linked networks and a balanced mechanical performance combining high strength, toughness, and biocompatibility. The combination of poly (ethylene glycol)-diacrylate (PEDGA) and sodium alginate (SA) enables the qualities mentioned earlier to be met, as well as the use of UV to prevent filament collapse under gravity. Critical correlations between the printability and settings, such as velocity and viscosity of the ink, were identified. PEGDA/alginate-based double network hydrogels were explored and prepared, and printing conditions were improved to achieve 3D complex architectures, such as tubular structures. The DN solution ink was found to be unsuitable for extrudability; hence, glycerol was added to enhance the process. Different glycerol concentrations and flow rates were investigated. The solution containing 25% glycerol and a flow rate of 2 mm/s yielded the best printing accuracy. Thanks to these parameters, a line width of 1 mm and an angle printing inaccuracy of less than 1° were achieved, indicating good shape accuracy. Once the optimal parameters were identified, a tubular structure was achieved with a high printing accuracy. This study demonstrated a 3D printing hydrogel structure using a commercial 3D bio-printer (REGEMAT 3D BIO V1) by synchronizing all parameters, serving as a reference for future more complex 3D structures.

Use of fuzzy neural networks in modeling relationships of HPV infection with apoptotic and proliferation markers in potentially malignant oral lesions.

To evaluate in oral leukoplakia the relationship between HPV infection and markers of apoptosis (bcl-2, survivin) and proliferation (PCNA), also conditionally to age, gender, smoking and drinking habits of patients, by means of Fuzzy neural networks (FNN) system 21 cases of oral leukopakia, clinically and histologically diagnosed, were examined for HPV DNA presence, bcl-2, survivin and PCNA expression. HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR: MY09-MY11/GP5-GP6), and the HPV genotype determined by direct DNA sequencing. All markers were investigated by means of standardised immunohistochemistry procedure. Data were analysed by chi-square test, crude OR and the 95% CI; in blindness, FNN was applied. HPV DNA was found in 8/21 OL (38.1%); survivin, PCNA, and tobacco smoking were associated in univariate analysis (p = 0.04) with HPV DNA status. HPV-18 was the most frequently detected genotype (6/8), followed by HPV-16 (2/8). FNN revealed that survivin and PCNA, both being expressed in all of OL HPV+ve, were associated with HPV infection. In conclusion, the FNN allowed to hypothesise a model of specific variables associated to HPV infection in OL. The relevance of survivin and PCNA suggest that they may be involved in HPV-mediated deregulation of epithelial maturation and, conversely, that HPV may have a role in the expression level of these two markers. FNN system seems to be an effective tool in the analysis of correlates of OL and HPV infection.

HPV DNA and survivin expression in epithelial oral carcinogenesis: a relationship?

HPV has been thought to be involved in the development of several oral diseases, such as premalignant mucosal lesions and oral carcinoma. Survivin is a recently characterized IAP protein, which is abundantly expressed in most solid and haematological malignancies, but undetectable in normal adult tissues. Aim of this study was to investigate survivin expression and HPV presence in oral premalignant lesions and oral carcinoma. 47 samples of oral tissue including 11 squamous cell carcinomas (OSCC), 16 oral leukoplakias (OL) and 20 normal oral mucosa specimens, after investigation of HPV presence by nested PCR (consensus MY/GP primers) and viral genotype identification by direct sequencing were investigated by immunohistochemistry to detect survivin expression. Survivin expression was evident in 4/7 (57.1%) HPV+ and 4/4 (100%) HPV- OSCC, 6/7 (85.7%) HPV+ and 5/9 (55.5%) HPV- OL and in 0/20 (0%) control samples. Data showed high levels of survivin expression in HPV-positive SCCs, even if mean values were lower than HPV-negative ones, which in particular showed survivin expression in 100% of cases. Conversely, survivin expression was greater in HPV+ precancerous lesions than in HPV- ones. Our findings suggest that survivin may be involved in HPV- mediated deregulation during maturation of squamous epithelium through modulation of the apoptotic processes and, conversely, HPV may have a direct or indirect effect on the regulation of the survivin expression level. In particular, the results of this study suggest distinguishing between cancerous and precancerous oral lesions with respect to survivin expression when HPV infection is present. The most unfavourable behaviour is likely to be for the HPV- OSCC.

Orbital rhabdomyosarcoma: relationship between DNA ploidy, p53, bcl-2, MDR-1 and Ki67 (MIB1) expression and clinical behavior.

BACKGROUND: As for rhabdomyosarcoma (RMS) of other anatomic regions, the evaluation of traditional clinicopathological parameters does not allow the unequivocal outcome prediction of the single cases of orbital RMS. We investigated the role of DNA ploidy and immunohistochemical expression of p53, bcl-2, MDR-1 and Ki67 (MIB1) in the prognostic evaluation of orbital rhabdomyosarcomas. MATERIALS AND METHODS: The study population consisted of 11 selected cases. Serial sections of each tumor, stained with Feulgen's technique, were analyzed for the DNA content, using the QUANTIMET 500c Leica analyzer, QWINVO200A software. The results were compared with the immunohistochemical expression of p53 (wild plus mutated, W&M and mutated), bcl2, MDR-1 and Ki67 (MIB1), and with follow-up data. RESULTS: The statistical analysis of results showed that the cases of tetraploid and/or multiploid RMS, overexpressing p53 (W&M and mutated) and MDR-1, were characterized by an overall worse prognosis. On the contrary, the tumors with a favourable clinical course showed hyperexpression of MIB1 and absence of mutated p53 expression. Significantly higher MIB1 expression was found in the relapse-free group of tumors, with respect to the RMS with relapse (both in primary tumors and relative relapses, p<0.05). This finding could justify the higher sensibility to pharmacological therapy of RMS of the first group. The group of RMS with a worse prognosis (primary tumors and relapses) showed instead p53 overexpression (W&M and mutated), MDR-1 expression and multiploidy, with high 5cEE values and tetraploid peaks. No significant difference was found concerning the expression of bcl-2 among the two groups of RMS (p>0.05). CONCLUSION: The evaluation of DNA ploidy, p53, MIB1 and MDR-1 expression could be used for subtyping of orbital RMS into two prognostically different subcategories, respectively RMS responder to the therapy, with favourable clinical outcome, and RMS with a worse prognosis, requiring more aggressive therapeutic protocols.