Yoshinao Oki

Although the liver possesses remarkable regenerative capacity, the detailed chronology spanning the pre-proliferative preparatory stage, hepatocyte proliferation, liver weight recovery, and the completion of molecular regeneration has not been fully elucidated. Using microarray-guided histological validation, we investigated the temporally ordered physiological events underlying liver regeneration following 70% partial hepatectomy (PH) in C57BL/6 mice. Our results demonstrated that PH induced multiple functional pathways, including the response to stilbenoid, steroid hormone metabolism, lipid transport, and angiogenesis. This was followed by activation of endoplasmic reticulum (ER) stress and insulin processing, accompanied by lipid accumulation, suppression of xenobiotic catabolic capacity, and altered circulating cholesterol levels. After recovery of these processes, hepatocytes and sinusoidal endothelial cells entered the proliferative phase. Notably, although liver weight had returned to preoperative levels, the transcriptome remained distinct from baseline, revealing divergence between macroscopic recovery and molecular-level convergence. At 336 h, two of three samples were assigned to the baseline Cluster 1, whereas one sample remained in Cluster 6 with a small number of altered genes. Together, these findings provide a detailed temporal framework in which metabolic and tissue remodeling during liver regeneration extends beyond macroscopic recovery.

The liver is capable of regeneration, regaining mass through compensatory hypertrophy even after resecting 70% of its mass. However, the underlying regenerative mechanism remains poorly understood. Thus, in this study, microarray data were procured over time, from 0 to 14 days post-70% partial hepatectomy (PH) in mice. This dataset was correlated with the body weight and liver weight measured at the time of liver harvest, allowing us to determine the progress of compensatory hypertrophy in each sample. Furthermore, the impact of individual differences in regenerative capacity was analyzed by preparing three biological replicates at each time point. The microarray data were confirmed to be of high quality based on the RNA integrity number and QC stats of the dataset. The reliability of the dataset was further supported by the results of hierarchical clustering and the expression variation of cell cycle–related genes. This microarray data will contribute to the elucidation of the regenerative mechanism in the 70% PH model.

Here, we established dedifferentiated fat (DFAT) cells from mature bovine adipocytes and then examined the effects of volatile fatty acids on the differentiation of these DFAT cells into adipocytes in vitro. When mature adipocytes were isolated from bovine adipose tissue and cultured using the ceiling culture method, they were dedifferentiated into fibroblast‐like cells without lipid droplets. These fibroblast‐like cells, termed bovine DFAT (b‐DFAT) cells, actively proliferated. After adipogenic induction, increased expression of adipocyte‐specific genes occurred in b‐DFAT cells and they redifferentiated into adipocytes with an accumulation of lipid droplets in their cytoplasm. The effects of volatile fatty acids on adipocyte differentiation in b‐DFAT cells were also examined. Specifically, acetate, butyrate, and propionate added to adipogenic induction medium significantly enhanced the adipogenesis of b‐DFAT cells compared with that observed in control cells; the addition of 10⁻³ mol of acetate enhanced adipogenesis of b‐DFAT cells to the greatest extent. These results suggest that b‐DFAT cells derived from bovine mature adipocytes are appropriate for the study of bovine adipocyte differentiation and that the optimum concentration treatment of acetate, a major energy source for ruminants, promotes adipogenesis of b‐DFAT cells in vitro.

The Forest Stewardship Council (FSC) and the Sustainable Green Ecosystem Council (SGEC) are deployed as forest certification schemes in Japan. This study aimed to identify the reasons that enterprises choose the FSC or the SGEC scheme and the effects of certification. A questionnaire survey was conducted on 126 forestry enterprises with certification as of May 2014. The results of questionnaire tabulation found different reasons for choosing FSC (high reliability of the international certification system) or SGEC (examination costs and difficulty of acquisition, certification acquisition by neighboring enterprises in the region, and guidance and information from familiar people and enterprises). The results suggest that choosing FSC or SGEC depended on international or domestic emphasis, reliability, cost, and difficulty of acquisition. Both schemes reportedly improved management planning, environmental impact assessments, and monitoring, but increased timber value was not reported. Japanese consumers’ understanding of forest certification should be enhanced and attention to forest management certification in Japan should increase because the SGEC now offers international certification. If SGEC certification is easier to obtain than FSC certification, and FSC is relatively expensive, the SGEC forest area should continue to expand.