Bone marrow adipose tissue (BMAT) resides within the bone marrow microenvironment where its function remains poorly understood. BMAT is elevated in anorexia nervosa, a disease model of chronic starvation, despite depletion of other fat depots. In addition to BMAT, the marrow microenvironment also consists of osteoblast and hematopoietic progenitors. BMAT is inversely associated with bone mineral density (BMD) in multiple populations including women with anorexia nervosa, and regulates hematopoiesis in animal models. We hypothesized that BMAT would be associated with circulating populations of hematopoietic cells (red and white blood cells) in humans and performed a post hoc analysis of two studies—a cross‐sectional study and a longitudinal study—to investigate this hypothesis. We studied 89 premenopausal women cross‐sectionally (median age [interquartile range], 27 [24.5, 31.7] years), including 35 with anorexia nervosa. We investigated associations between red blood cell (RBC) and white blood cell (WBC) counts and BMAT assessed by ¹H‐magnetic resonance spectroscopy, BMD assessed by DXA, and bone microarchitecture assessed by HR‐pQCT. In addition, we analyzed longitudinal data in six premenopausal women with anorexia nervosa treated with transdermal estrogen for 6 months and measured changes in BMAT and blood cell counts during treatment. Cross‐sectionally, BMAT was inversely associated with WBC and RBC counts. In contrast, BMD and parameters of bone microarchitecture were positively associated with WBC and RBC. In women with anorexia nervosa treated with transdermal estrogen for 6 months, decreases in BMAT were significantly associated with increases in both RBC and hematocrit (rho = −0.83, p = 0.04 for both). In conclusion, we show that BMAT is inversely associated with WBC and RBC in premenopausal women, and there is a potential association between longitudinal changes in BMAT and changes in RBC. These associations warrant further study and may provide further insight into the role and function of this understudied adipose depot. © 2020 American Society for Bone and Mineral Research.

中文翻译：

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红细胞和白细胞计数与绝经前女性的骨髓脂肪组织、骨矿物质密度和骨微结构相关。

骨髓脂肪组织 (BMAT) 存在于骨髓微环境中，但其功能仍知之甚少。尽管其他脂肪库已耗尽，但在神经性厌食症（一种慢性饥饿疾病模型）中，BMAT 仍升高。除 BMAT 外，骨髓微环境还由成骨细胞和造血祖细胞组成。BMAT 与多个人群（包括神经性厌食症女性）的骨矿物质密度 (BMD) 呈负相关，并在动物模型中调节造血功能。我们假设 BMAT 与人类造血细胞（红细胞和白细胞）的循环群体有关，并对两项研究（一项横断面研究和一项纵向研究）进行了事后分析，以调查这一假设。我们对 89 名绝经前女性进行了横断面研究（中位年龄 [四分位距] 27 [24.5, 31.7] 岁），其中 35 名患有神经性厌食症。我们研究了红细胞 (RBC) 和白细胞 (WBC) 计数与通过¹ H 磁共振波谱评估的 BMAT、通过 DXA 评估的 BMD 以及通过 HR-pQCT 评估的骨微结构之间的关联。此外，我们分析了六名患有神经性厌食症的绝经前女性接受透皮雌激素治疗 6 个月的纵向数据，并测量了治疗期间 BMAT 和血细胞计数的变化。从横截面来看，BMAT 与 WBC 和 RBC 计数呈负相关。相反，BMD 和骨微结构参数与 WBC 和 RBC 呈正相关。在接受透皮雌激素治疗 6 个月的神经性厌食症女性中，BMAT 的降低与红细胞和血细胞比容的增加显着相关（两者均为rho = -0.83， p = 0.04）。总之，我们表明绝经前女性的 BMAT 与 WBC 和 RBC 呈负相关，并且 BMAT 的纵向变化与 RBC 的变化之间存在潜在关联。这些关联值得进一步研究，并可能进一步深入了解这个未被充分研究的脂肪库的作用和功能。© 2020 美国骨与矿物质研究学会。