Moderate Hypothermia Has the Potential to Reveal the Dominant/Submissive Relationship in a Co-Culture System Consisting of Osteoblasts and Endothelial Cells

Microvessels in bone are indispensable for maintaining bone homeostasis based on a dynamic remodeling system. In cell-based tissue engineering, vascularization into the regenerative bone is a key strategy to avoid hypoxia and necrosis around re-implanted tissues. Previous studies have shown that direct contact between osteoblasts and endothelial cells stimulates differentiation of both cell types. However, no studies have revealed the dominant/submissive relationship. In the present study, we examined the effect of hypothermia on monoculture and co-culture to assess which cells tightly coordinated osteogenesis and angiogenesis in the co-culture system. As for osteoblasts, exposure to hypothermia suppressed cellular proliferation, migration, and differentiation. Evaluation of the behavior of endothelial cells showed that hypothermia should not affect basic functions such as proliferation and migration. Under co-culture conditions, both osteogenic differentiation and the formation of vessel-like angiogenic structures were suppressed by hypothermia, but the spatial organization of alkaline phosphatase-positive cell clusters, which tend to localize around microvascular lumens, was not altered. These data suggest that hypothermia attenuates heterotypic intercellular crosstalk which robustly depends on osteoblasts to inhibit both osteogenesis and angiogenesis in the co-culture system. Taken together, this approach will provide new insights into the relationship between osteoblasts and endothelial cells in tissue engineering

Co-Culture of Osteoblasts and Endothelial Cells on a Microfiber Scaffold to Construct Bone-Like Tissue with Vascular Networks

Bone is based on an elaborate system of mineralization and vascularization. In hard tissue engineering, diverse biomaterials compatible with osteogenesis and angiogenesis have been developed. In the present study, to examine the processes of osteogenesis and angiogenesis, osteoblast-like MG-63 cells were co-cultured with human umbilical vein endothelial cells (HUVECs) on a microfiber scaffold. The percentage of adherent cells on the scaffold was more than 60% compared to the culture plate, regardless of the cell type and culture conditions. Cell viability under both monoculture and co-culture conditions was constantly sustained. During the culture periods, the cells were spread along the fibers and extended pseudopodium-like structures on the microfibers three-dimensionally. Compared to the monoculture results, the alkaline phosphatase activity of the co-culture increased 3–6 fold, whereas the vascular endothelial cell growth factor secretion significantly decreased. Immunofluorescent staining of CD31 showed that HUVECs were well spread along the fibers and formed microcapillary-structures. These results suggest that the activation of HUVECs by co-culture with MG-63 could enhance osteoblastic differentiation in the microfiber scaffold, which mimics the microenvironment of the extracellular matrix. This approach can be effective for the construction of tissue-engineered bone with vascular networks

Tolerability, Efficacy, and Safety of Bisoprolol vs. Carvedilol in Japanese Patients With Heart Failure and Reduced Ejection Fraction - The CIBIS-J Trial -

Background: The comparative tolerability, efficacy, and safety of bisoprolol and carvedilol have not been established in Japanese patients with heart failure and reduced ejection fraction (HFrEF). Methods and Results: The CIBIS-J trial is a multicenter, open-label, non-inferiority randomized controlled trial of bisoprolol vs. carvedilol in 217 patients with HFrEF (EF <= 40%). The primary endpoint was tolerability, defined as reaching and maintaining the maximum maintenance dose (bisoprolol 5 mg/day or carvedilol 20 mg/day) during 48 weeks of treatment. The primary endpoint was achieved in 41.4% of patients in bisoprolol (n=111) and 42.5% in carvedilol (n=106) groups. The non-inferiority of tolerability of bisoprolol compared with carvedilol was not supported, however, neither beta-blocker was superior with regard to tolerability. Heart rate (HR) decreased in both groups and its decrease from baseline was significantly greater in the bisoprolol group (20.3 vs. 15.4 beats/min at 24 week, P<0.05). Plasma B-type natriuretic peptide (BNP) levels decreased in both groups and the decrease was significantly greater in the carvedilol group (12.4 vs. 39.0 % at 24 weeks, P<0.05). Conclusions: There were no significant differences between bisoprolol and carvedilol in the tolerability of target doses in Japanese HFrEF patients. The clinical efficacy and safety were also similar despite the greater reduction in HR by bisoprolol and plasma BNP by carvedilol