Antioxidant Functionality in Hepatocytes Using the Enhanced Collagen Extracellular Matrix Under Different Oxygen Tensions

Abstract

Improvement of O(2) supply in bioartificial liver devices remains a critical issue in maintaining hepatocyte viability and functions. Therefore, the current study investigates whether enhanced oxygen (O(2)) transport through collagen extracellular matrix (ECM) can produce a more stable antioxidant defense in different O(2) tensions during prolonged incubation times. Total glutathione concentration of cultured hepatocytes in enhanced ECM was significantly higher than in normal ECM under the lowest O(2) tension phase (2.60mm of thickness from O(2) source), and was also significantly increased in 0.52 mm transport distance of hypoxia as compared to normoxic conditions. Catalase and glutathione reductase activities for hepatocytes within enhanced ECM were also significantly preserved relative to their values for the normal collagen ECM. Specifically, the enhanced ECM produced higher activities at a further transport distance (1.56 mm) from the O(2) source at the 24 h time-point, and remained higher up to the 96 h incubation time. In contrast, the glutathione peroxidase activities in both collagen ECM systems were similar. Hepatocyte viability in the enhanced ECM system was also consistently greater than that for normal ECM. These results suggest that the O(2) enhanced collagen ECM preserves the antioxidant defense system as compared to normal collagen ECM, ostensibly via increased micropathways for O(2) transport to the hepatocytes.

Vascularization in Bone Tissue Engineering: Physiology, Current Strategies, Major Hurdles and Future Challenges

“…[2,7,8] In the absence of a vascular supply, the transport of nutrients occurs mainly by diffusion, a transport mechanism that is only efficient over short distances or for tissues with low metabolic activity (e.g., cartilage). Theoretical modeling predicts [2] that a centimeter thick scaffold without a vascular supply can support the metabolism of 280 000 cells Á cm À3 without central necrosis; in native cancelous bone, this value is 1000-fold higher.…”

The additive effects of photobiomodulation and bioactive glasses on enhancing early angiogenesis

“…Concomitant blood vessels play a vital role in supplying oxygen and nutrients to newly formed tissues, eliminating metabolites, delivering growth factors and providing key signals for bone metabolism [30]. Insufficient early angiogenesis will hinder the biomaterial fusion and absorption with tissues, and then hindering the bone regeneration [12,13]. Some studies have demonstrated the effect of BG on promoting angiogenesis [31][32][33], but the early proangiogenic capacity of BG, especially the early angiogenesis in large-sized bone defects filled with BG, needs more studies [9][10][11].…”

“…Meanwhile, some literatures also pointed out that acute inflammatory reactions will occur when biomaterials are implanted, which will inhibit the angiogenesis process of osteoblasts and epithelial cells [10,11]. The inadequate early angiogenesis of BG may result in insufficient nutrient supplies and harmful microenvironment changes, which weakens its osteogenic effects in large-sized bone defects repair, leading to ischemia and tissue necrosis in the central region of bone defects or ultimately the failure of bone regeneration [12,13]. Therefore, inadequate angiogenesis is a problem that has created a bottleneck in tissue engineering.…”

The modern creation technologies of implanted bioartificial liver

“…Снабжение кислородом является лимитирующим фактором при культивировании активно метаболизирующих клеток, таких как гепатоциты [9][10][11]. Nahmias и соавт.…”