Macromolecular synthesis in the livers of aging mice as revealed by electron microscopic radioautography

How is Big Data reshaping preclinical aging research?

The exponential scientific and technological progress during the past 30 years has favored the comprehensive characterization of aging processes with their multivariate nature, leading to the advent of Big Data in preclinical aging research. Spanning from molecular omics to organism-level deep phenotyping, Big Data demands large computational resources for storage and analysis, as well as new analytical tools and conceptual frameworks to gain novel insights leading to discovery. Systems biology has emerged as a paradigm that utilizes Big Data to gain insightful information enabling a better understanding of living organisms, visualized as multilayered networks of interacting molecules, cells, tissues and organs at different spatiotemporal scales. In this framework, where aging, health and disease represent emergent states from an evolving dynamic complex system, context given by, for example, strain, sex and feeding times, becomes paramount for defining the biological trajectory of an organism. Using bioinformatics and artificial intelligence, the systems biology approach is leading to remarkable advances in our understanding of the underlying mechanism of aging biology and assisting in creative experimental study designs in animal models. Future in-depth knowledge acquisition will depend on the ability to fully integrate information from different spatiotemporal scales in organisms, which will probably require the adoption of theories and methods from the field of complex systems. Here we review state-of-the-art approaches in preclinical research, with a focus on rodent models, that are leading to conceptual and/or technical advances in leveraging Big Data to understand basic aging biology and its full translational potential.

Electron Microscopic Radioautographic Study on the Protein Synthesis in the Pancreas of Aging Mice With Special Reference to Mitochondria

BACKGROUND

The purpose of this study was to investigate the aging changes of macromolecular synthesis in animal cells.

METHODS

We studied 10 groups of mice during development aged from fetal day 19 to postnatal month 24. They were injected with 3H-leucine, a precursor for protein synthesis, sacrificed and the pancreatic tissues were taken out, fixed and processed for light and electron microscopic radioautography. On many radioautograms the localization of silver grains demonstrating protein synthesis in pancreatic acinar cells in respective aging groups were first analyzed qualitatively. Then the number of silver grains and the number of cell organelles in each cell in respective aging groups were analyzed quantitatively in relation to the aging of animals. The number of mitochondria, the number of labeled mitochondria and the mitochondrial labeling index labeled with silver grains were counted in each pancreatic acinar cell.

RESULTS AND CONCLUSIONS

The number of silver grains in cell nuclei and cell organelles changed with the aging of animals. The number of mitochondria, the number of labeled mitochondria and the labeling indices showing protein synthesis at various ages increased from embryonic day 19 to postnatal newborn day 1, 3, 7, 14, to young adult month 1, and 2, reaching the maxima, then decreased at old adult month 6 and senile year 1 to 2, indicating the aging changes.

Prognosis of patients with hepatocellular carcinoma after hepatic resection: are elderly patients suitable for surgery?

AIM

The indication for hepatectomy is still controversial in elderly patients with hepatocellular carcinoma (HCC). We examined the clinicopathological features and survival of 188 HCC patients who underwent hepatectomy.

PATIENTS/METHODS

Patients were divided into four age groups: Age(<50) group (young patients <50 years of age, n = 9), Age(50-69) group (between 50-69 years, n = 110), Age(70-79) group (70-79 years, n = 57), and Age(≥80) group (≥80 years, n = 12). Physiologic ability and surgical stress (E-PASS) score, including preoperative risk score (PRS), surgical stress score (SSS), and comprehensive risk score (CRS) were assessed.

RESULTS

Proportion of patients of Age(70-79) and Age(≥80) groups increased significantly in the last 5 years (P < 0.01). Co-morbidity, performance status, and American Society of Anesthesiologists score significantly increased with age (P < 0.05). Proportions of patients with irregular findings and necro-inflammatory activity were significantly lower in Age(70-79) and Age(≥80) groups than in other groups (P < 0.05). Systemic postoperative complications were high in Age(70-79) and Age(≥80) groups. PRS increased significantly with age (P < 0.05). Multivariate analysis identified PRS ≥0.32 and age ≥70 years as significant determinants of systemic complications (P < 0.05). There were no significant differences in postoperative survivals among the groups.

CONCLUSIONS

Careful follow-up and proper decision on hepatectomy upon assessment of PRS are important in elderly HCC patients.