Review of recent research on hepatitis C therapy for 54th annual meeting of the American association for the study of liver diseases

Since it was first discovered, thousands of years ago, silkworm silk has been known to be an abundant biopolymer with a vast range of attractive properties. The utilization of silk fibroin (SF), the main protein of silkworm silk, has not been limited to the textile industry but has been further extended to various high-tech application areas, including biomaterials for drug delivery systems and tissue engineering. The outstanding mechanical properties of SF, including its facile processability, superior biocompatibility, controllable biodegradation, and versatile functionalization have allowed its use for innovative applications. In this review, we describe the structure, composition, general properties, and structure-properties relationship of SF. In addition, the methods used for the fabrication and modification of various materials are briefly addressed. Lastly, recent applications of SF-based materials for small molecule drug delivery, biological drug delivery, gene therapy, wound healing, and bone regeneration are reviewed and our perspectives on future development of these favorable materials are also shared.

https://www.mdpi.com/2073-4360/11/12/1933/pdf

Silk Fibroin-Based Biomaterials for Biomedical Applications: A Review

In vitro cell performance on hydroxyapatite particles/poly(L-lactic acid) nanofibrous scaffolds with an excellent particle along nanofiber orientation.

Bioactive behavior of silicon substituted calcium phosphate based bioceramics for bone regeneration

The success of scaffold-based bone regeneration approaches strongly depends on the performance of the biomaterial utilized. Within the efforts of regenerative medicine towards a restitutio ad integrum (i.e. complete reconstruction of a diseased tissue), scaffolds should be completely degraded within an adequate period of time. The degradation of synthetic bone substitute materials involves both chemical dissolution (physicochemical degradation) and resorption (cellular degradation by osteoclasts). Responsible for bone resorption are osteoclasts, cells of haematopoietic origin. Osteoclasts play also a crucial role in bone remodelling, which is essential for the regeneration of bone defects. There is, however, surprisingly limited knowledge about the detailed effects of osteoclasts on biomaterials degradation behaviour. This review covers the relevant fundamental knowledge and progress made in the field of osteoclast activity related to biomaterials used for bone regeneration. In vitro studies with osteoclastic precursor cells on synthetic bone substitute materials show that there are specific parameters that inhibit or enhance resorption. Moreover, analyses of the bone-material interface reveal that biomaterials composition has a significant influence on their degradation in contact with osteoclasts. Crystallinity, grain size, surface bioactivity and density of the surface seem to have a less significant effect on osteoclastic activity. In addition, the topography of the scaffold surface can be tailored to affect the development and spreading of osteoclast cells. The present review also highlights possible areas on which future research is needed and which are relevant to enhance our understanding of the complex role of osteoclasts in bone tissue engineering.

The role of osteoclasts in bone tissue engineering

Calcium phosphate-based materials should show excellent bone-bonding and cell-mediated resorption characteristics at the same time, in order to be employed for bone replacement. In this perspective, pure (HAp) and silicon-substituted hydroxyapatite (Si-HAp, 1.4% wt) porous cylinders were prepared starting from synthesized powders and polyethylene spheres used as porogens, and investigated as supports for osteoblast and osteoclast progenitor differentiation. A systematic and detailed biological characterization is reported, in terms of cell adhesion, viability, proliferation, differentiation and bioresorption, aimed at proposing a complete and reliable picture of bone cell in vitro behavior, comprehensive of both the osteogenesis and the bone resorption processes. In order to achieve this purpose, cytocompatibility, differentiation and gene expression by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were carried out using parietal bone-derived pre-osteoblasts obtained from neonatal mice and the bioresorption capability was assessed by seeding human peripheral blood monocytes, as osteoclast precursors. It resulted that both pure and Si-substituted HAps were able to promote differentiation of precursor cells in mature osteoblasts and osteoclasts. In particular, the Si-HAps enhanced the pre-osteoblast proliferation and showed higher osteoclast-mediated bioresorption capability, as supported by the presence of larger and more numerous resorption lacunae, whereas HAps promoted a more robust cell differentiation in terms of both osteocalcin gene expression by qRT-PCR and cell morphological evaluation by SEM analysis.

https://iopscience.iop.org/article/10.1088/1748-6041/7/5/055001/pdf

Differentiation of osteoblast and osteoclast precursors on pure and silicon-substituted synthesized hydroxyapatites

Biocompatible and biodegradable scaffolds can provide a convenient support for stem cell differentiation leading to tissue
formation. Porous hydroxyapatite (HAp) scaffolds are clinically used for applications such as spinal fusions, bone tumors,
fractures, and in the replacement of failed or loose joint prostheses. The incorporation of small amounts of silicon within
hydroxyapatite lattice significantly improves HAp solubility and rate of bone apposition, as well as the proliferation of human
osteoblasts in vitro. In the present paper we report biocompatibility data obtained on a newly designed three-dimensional
nano-structured porous scaffold made of pure and silicon-substituted hydroxyapatite. A suitable amount of porosity (60 vol%)
was obtained within a well densified ceramic skeleton by using polyethylene spheres. Biocompatibility was tested by using
murine embryonic stem cells (ES). Cell culture analysis indicated that ES cells adhere well on both hydroxyapatite and
silicon-substituted hydroxyapatite scaffolds. Si-substitution, however, improved subsequent ES cell proliferation rate.
Bioresorption of hydroxyapatite scaffolds was tested by using human osteoclasts obtained from peripheral blood monocytes,
made to differentiate on disks and evaluated by SEM analysis.

/pdf/design-production-and-biocompatibility-of-nanostructured-93kwq2ww6y.pdf

Design, production and biocompatibility of nanostructured porous HAp and Si-HAp ceramics as three-dimensional scaffolds for stem cell culture and differentiation

Different expression of VEGF and EGFL7 in human hepatocellular carcinoma.

In this work, the sol-gel synthesis of AP40 bioactive glass system was reported. The obtained powder was fully characterised in terms of microstructure, composition and thermal behaviour by X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry and differential thermal analysis (TG-DTA). In vitro dissolution tests were performed in order to assess the degradation behaviour of sol-gel derived AP40 samples thermally treated at different temperatures. Finally, preliminary results on cytocompatibility are reported, based on bioresorption activity of human peripheral blood monocytes differentiated into osteoclasts on sintered disks.

G Lehmann

Papers

Differentiation of osteoblast and osteoclast precursors on pure and silicon-substituted synthesized hydroxyapatites

Design, production and biocompatibility of nanostructured porous HAp and Si-HAp ceramics as three-dimensional scaffolds for stem cell culture and differentiation

Different expression of VEGF and EGFL7 in human hepatocellular carcinoma.

AP40 bioactive glass ceramic by sol-gel synthesis: in vitro dissolution and cell-mediated bioresorption

Liver, Pancreas and Biliary Tract Different expression of VEGF and EGFL7 in human hepatocellular carcinoma