Over the last decade DLW employing ultrafast pulsed lasers has become a well-established technique for the creation of custom-made free-form three-dimensional (3D) microscaffolds out of a variety of materials ranging from proteins to biocompatible glasses. Its potential applications for manufacturing a patient’s specific scaffold seem unlimited in terms of spatial resolution and geometry complexity. However, despite few exceptions in which live cells or primitive organisms were encapsulated into a polymer matrix, no demonstration of an in vivo study case of scaffolds generated with the use of such a method was performed. Here, we report a preclinical study of 3D artificial microstructured scaffolds out of hybrid organic-inorganic (HOI) material SZ2080 fabricated using the DLW technique. The created 2.1 × 2.1 × 0.21 mm3 membrane constructs are tested both in vitro by growing isolated allogeneic rabbit chondrocytes (Cho) and in vivo by implanting them into rabbit organisms for one, three and six months. An ex vivo histological examination shows that certain pore geometry and the pre-growing of Cho prior to implantation significantly improves the performance of the created 3D scaffolds. The achieved biocompatibility is comparable to the commercially available collagen membranes. The successful outcome of this study supports the idea that hexagonal-pore-shaped HOI microstructured scaffolds in combination with Cho seeding may be successfully implemented for cartilage tissue engineering.

BackgroundOsteochondral allograft transplantation has a good clinical outcome, however, there is still debate on optimization of allograft storage protocol. Storage temperature and nutrient medium composition are the most critical factors for sustained biological activity of grafts before implantation. In this study, we performed a time-dependent in vitro experiment to investigate the effect of various storage conditions on electromechanical, histological and histochemical properties of articular cartilage.MethodsOsteochondral grafts derived from goat femoral condyles were frozen at −70 °C or stored at 4 °C and 37 °C in the medium supplemented with or without insulin-like growth factor-1 (IGF-1). After 14 and 28 days the cartilage samples were quantitatively analysed for electromechanical properties, glycosaminoglycan distribution, histological structure, chondrocyte viability and apoptosis. The results were compared between the experimental groups and correlations among different evaluation methods were determined.ResultsStorage at −70 °C and 37 °C significantly deteriorated cartilage electromechanical, histological and histochemical properties. Storage at 4 °C maintained the electromechanical quantitative parameter (QP) and glycosaminoglycan expression near the normal levels for 14 days. Although hypothermic storage revealed reduced chondrocyte viability and increased apoptosis, these parameters were superior compared with the storage at −70 °C and 37 °C. IGF-1 supplementation improved the electromechanical QP, chondrocyte viability and histological properties at 37 °C, but the effect lasted only 14 days. Electromechanical properties correlated with the histological grading score (r = 0.673, p < 0.001), chondrocyte viability (r = −0.654, p < 0.001) and apoptosis (r = 0.416, p < 0.02). In addition, apoptosis correlated with glycosaminoglycan distribution (r = −0.644, p < 0.001) and the histological grading score (r = 0.493, p = 0.006).ConclusionsOur results indicate that quality of allografts is better preserved at currently established 4 °C storage temperature. Storage at −70 °C or at 37 °C is unable to maintain cartilage function and metabolic activity. IGF-1 supplementation at 37 °C can enhance chondrocyte viability and improve electromechanical and histological properties of the cartilage, but the impact persists only 14 days. The correlations between cartilage electromechanical quantitative parameter (QP) and metabolic activity were detected. Our findings indicate that non-destructive assessment of cartilage by Arthro-BST is a simple and reliable method to evaluate allograft quality, and could be routinely used before implantation.

Current advances in stem cell research and innovative biological approaches in the field of tissue engineering and regenerative medicine could eventually translate into prospective clinical applications. Various adult organs and tissues harbor stem and progenitor cells that could potentially be used to repair, regenerate, and restore a variety of different tissues following acute injury or tissue destructive diseases. Skeletal muscle is a very convenient and plentiful source of somatic stem cells. It contains several distinct populations of myogenic stem cells including satellite cells that are mainly responsible for muscle growth and regeneration, and multipotent muscle-derived stem cells (MDSCs). Although both cell populations share some phenotypic similarities, MDSCs display a much greater differentiation potential in vitro and are capable of regenerating various tissues in vivo. Furthermore, these cells not only participate in the regeneration process by differentiating into tissue-specific cell types, but also promote endogenous tissue repair by secreting a multitude of trophic factors. In this article, we describe the biological aspects of MDSC isolation and characterization and provide an overview of potential therapeutic application of these cells for the treatment of cardiac and skeletal muscle injuries and diseases, urological dysfunction, and bone and cartilage defects. We also discuss major challenges and limitations currently faced by MDSC-based therapies that await resolution before these techniques can be applied clinically.

Skeletal muscle-derived stem/progenitor cells (MDSPCs) have been thoroughly investigated and already used in preclinical studies. However, therapeutic potential of MDSPCs isolated using preplate isolation technique for acute kidney injury (AKI) has not been evaluated. We aimed to characterize rat MDSPCs, compare them with bone marrow mesenchymal stem cells (BM-MSCs), and evaluate the feasibility of MDSPCs therapy for gentamicin-induced AKI in rats. We have isolated and characterized rat MDSPCs and BM-MSCs. Characteristics of rat BM-MSCs and MDSPCs were assessed by population doubling time, flow cytometry, immunofluorescence staining, RT-PCR, and multipotent differentiation capacity. Gentamicin-induced AKI model in rat was used to examine MDSPCs therapeutic effect. Physiological and histological kidney parameters were determined. MDSPCs exhibited similar immunophenotype, stem cell gene expression, and multilineage differentiation capacities as BM-MSCs, but they demonstrated higher proliferation rate. Single intravenous MDSPCs injection accelerated functional and morphological kidney recovery, as reflected by significantly lower serum creatinine levels, renal injury score, higher urinary creatinine, and GFR levels. PKH-26-labeled MDSPCs were identified within renal cortex 1 and 2 weeks after cell administration, indicating MDSPCs capacity to migrate and populate renal tissue. In conclusion, MDSPCs are capable of mediating functional and histological kidney recovery and can be considered as potential strategy for AKI treatment.