Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Front Endocrinol (Lausanne). 2022 Jan 25;12:782194. doi: 10.3389/fendo.2021.782194. eCollection 2021.
Exercise, typically beneficial for skeletal health, has not yet been studied in lipodystrophy, a condition characterized by paucity of white adipose tissue, with eventual diabetes, and steatosis. We applied a mouse model of global deficiency of Bscl2 (SEIPIN), required for lipid droplet formation. Male twelve-week-old B6 knockouts (KO) and wild type (WT) littermates were assigned six-weeks of voluntary, running exercise (E) versus non-exercise (N=5-8). KO weighed 14% less than WT (p=0.01) and exhibited an absence of epididymal adipose tissue; KO liver Plin1 via qPCR was 9-fold that of WT (p=0.04), consistent with steatosis. Bone marrow adipose tissue (BMAT), unlike white adipose, was measurable, although 40.5% lower in KO vs WT (p=0.0003) via 9.4T MRI/advanced image analysis. SEIPIN ablation's most notable effect marrow adiposity was in the proximal femoral diaphysis (-56% KO vs WT, p=0.005), with relative preservation in KO-distal-femur. Bone via μCT was preserved in SEIPIN KO, though some quality parameters were attenuated. Running distance, speed, and time were comparable in KO and WT. Exercise reduced weight (-24% WT-E vs WT p<0.001) but not in KO. Notably, exercise increased trabecular BV/TV in both (+31%, KO-E vs KO, p=0.004; +14%, WT-E vs WT, p=0.006). The presence and distribution of BMAT in SEIPIN KO, though lower than WT, is unexpected and points to a uniqueness of this depot. That trabecular bone increases were achievable in both KO and WT, despite a difference in BMAT quantity/distribution, points to potential metabolic flexibility during exercise-induced skeletal anabolism.
运动通常对骨骼健康有益,但在脂肪营养不良症中尚未进行研究,脂肪营养不良症的特征是白色脂肪组织减少,最终会导致糖尿病和脂肪变性。我们应用了全身性缺乏 Bscl2(SEIPIN)的小鼠模型,Bscl2 是形成脂滴所必需的。将 12 周龄雄性 B6 敲除(KO)和野生型(WT)同窝仔鼠分配到 6 周的自愿跑步运动(E)或非运动(N=5-8)组。KO 体重比 WT 低 14%(p=0.01),且附睾脂肪组织缺失;KO 肝脏 Plin1 通过 qPCR 检测为 WT 的 9 倍(p=0.04),与脂肪变性一致。骨髓脂肪组织(BMAT)与白色脂肪组织不同,虽然通过 9.4T MRI/高级图像分析,KO 比 WT 低 40.5%(p=0.0003),但仍可测量。SEIPIN 消融对骨髓脂肪组织的最显著影响是在股骨近端骨干(-56%KO 比 WT,p=0.005),而 KO 远端股骨相对保留。通过 μCT 保留了 SEIPIN KO 的骨量,尽管一些质量参数减弱。KO 和 WT 的跑步距离、速度和时间相当。运动降低了体重(WT-E 比 WT 降低 24%,p<0.001),但 KO 没有降低。值得注意的是,运动增加了小梁骨体积分数(BV/TV)(KO-E 比 KO 增加 31%,p=0.004;WT-E 比 WT 增加 14%,p=0.006)。SEIPIN KO 中 BMAT 的存在和分布虽然低于 WT,但出乎意料,表明该脂肪库具有独特性。尽管 KO 和 WT 之间的 BMAT 数量/分布存在差异,但小梁骨增加是可以实现的,这表明运动诱导的骨骼合成代谢过程中存在潜在的代谢灵活性。
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