新华社洛杉矶4月27日电 人到中年腰围渐宽，远不止影响外观这么简单。腹部脂肪会加速衰老、减缓 代谢，增加患糖尿病、心脏病等慢性疾病的风险。然而，衰老怎么使得腹肌变成松软肚腩，这背后的机 制并不清晰。 美国希望之城国际医疗中心、加州大学洛杉矶分校等机构的研究人员在新一期《科学》杂志发表的一项 临床前研究，揭示了年龄相关性腹部脂肪堆积的细胞"元凶"，为解释中年发福现象提供了全新科学依 据。 研究人员聚焦于脂肪祖细胞（APCs），即白色脂肪组织中能分化为脂肪细胞的干细胞群。大多数成体 干细胞的增殖能力会随年龄衰退，但脂肪祖细胞恰恰相反——衰老反而释放了它们分化扩张的潜能。 他们先将年轻与老年小鼠的脂肪祖细胞移植到另一组年轻小鼠体内，结果老年小鼠的脂肪祖细胞迅速生 成了大量脂肪细胞。而当年轻小鼠的脂肪祖细胞被移植到老年小鼠体内时，未能大量生成新的脂肪细 胞。这证实，老年脂肪祖细胞具备独立生成新脂肪细胞的能力，与宿主年龄无关。基因活性分析显示， 脂肪祖细胞在年轻小鼠体内几乎处于休眠状态，却在中年小鼠体内异常活跃，开始大量生成新脂肪细 胞。 研究还发现，衰老会使脂肪祖细胞转化为一种新型干细胞——定型前脂肪细胞。这类细胞在 ...

Core Insights - The article discusses the phenomenon of increased fat accumulation in middle-aged individuals, particularly focusing on the role of adipose progenitor cells (APCs) and their enhanced ability to generate new fat cells as people age [1][3][6] Group 1: Mechanisms of Fat Accumulation - The increase in individual fat tissue occurs through two main processes: hypertrophy (enlargement of fat cells) and adipogenesis (generation of new fat cells) [3] - Contrary to previous beliefs that APCs decrease in proliferation with age, recent studies show that APCs in middle-aged individuals actually become more active, leading to increased fat cell generation [3][5] Group 2: Research Findings - In studies involving male mice aged 12 months (equivalent to approximately 45 years in humans), significant increases in body weight and fat tissue were observed, with visceral fat increasing by 4.6 times and subcutaneous fat by 2.8 times [3] - Over 80% of the fat cells in the visceral fat tissue of these older mice were newly generated, indicating a robust adipogenesis process [3] Group 3: Identification of New Cell Types - Researchers identified a new subgroup of adipose progenitor cells, termed CP-A cells, which emerge around 9 months of age in mice and peak at 12 months [5] - These CP-A cells exhibit strong proliferation and differentiation capabilities, contributing to the active generation of fat cells in middle-aged individuals [5][6] Group 4: Implications for Human Health - Similar CP-A cell populations were found in human adipose tissue, suggesting that humans may experience analogous changes in fat cell dynamics as they age [6] - The study identified the leukemia inhibitory factor receptor (LIFR) as a crucial molecule for fat generation in CP-A cells, indicating potential therapeutic targets for preventing middle-aged obesity [6]