Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America.
Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America.
Bone. 2021 Nov;152:116093. doi: 10.1016/j.bone.2021.116093. Epub 2021 Jun 27.
Bone marrow adipose tissue (BMAT) plays a role in systemic energy metabolism and responds to nutritional changes. Chronic starvation as well as visceral adiposity are associated with BMAT accumulation. Two types of BMAT have been described which differ in anatomic location (proximal-regulated-rBMAT vs distal-constitutive-cBMAT) and composition (higher unsaturated lipids of cBMAT compared to rBMAT).
To determine the response of BMAT composition to short-term high-caloric feeding and fasting. We hypothesized that high-feeding and caloric restriction would be associated with differences in BMAT composition according to the skeletal site.
We examined 23 healthy subjects (13 m, 10 f, mean age 33 ± 7 years, BMI 26 ± 1.5 kg/m) who were admitted for a 10-day high-caloric stay (caloric intake with goal to achieve 7% weight gain) followed by discharge home for 13-18 days to resume normal diet (stabilization period), followed by a 10-day fasting stay (no caloric intake). Subjects underwent single voxel proton MR spectroscopy (1H-MRS) at 3T of the lumbar spine (L4) (rBMAT), the femoral diaphysis and distal tibial metaphysis (cBMAT) to determine BMAT composition (unsaturation index, UI and saturation index, SI). Within group comparisons were performed by the Wilcoxon signed rank test.
After the high-calorie visit, SI of L4 increased compared to baseline (0.62 ± 0.27 to 0.70 ± 0.28, p = 0.02), and there was a trend of an increase in femoral SI and UI (p ≥ 0.07), while there was no significant change in tibial BMAT (p ≥ 0.13). During the stabilization period, SI of L4 decreased (0.70 ± 0.28 to 0.57 ± 0.21, p < 0.0001) and SI of the femoral diaphysis decreased (5.37 ± 2.27 to 5.09 ± 2.43, p = 0.03), while there was no significant change in UI or tibial BMAT (p ≥ 0.14). During the fasting period, SI of L4 increased (0.57 ± 0.21 to 0.63 ± 0.30, p = 0.03), while there was no change in UI (p = 0.7). SI and UI of femoral diaphysis decreased (5.09 ± 2.43 to 4.68 ± 2.15, p = 0.03, and 0.62 ± 0.42 to 0.47 ± 0.37, p = 0.02, respectively) and UI of the tibial metaphysis decreased (1.48 ± 0.49 to 1.24 ± 0.57, p = 0.04).
1H-MRS is able to quantify BMAT composition during short-term nutritional challenges, showing a significant increase in SI of rBMAT during high caloric feeding and a differential response to fasting with an increase in SI of rBMAT and a decrease in SI and UI of femoral cBMAT and decrease in UI of tibial cBMAT.
骨髓脂肪组织（BMAT）在全身能量代谢中发挥作用，并对营养变化做出反应。慢性饥饿和内脏肥胖与 BMAT 积累有关。已经描述了两种 BMAT，它们在解剖位置（近端调节-rBMAT 与远端组成-cBMAT）和组成（与 rBMAT 相比，cBMAT 具有更高的不饱和脂质）上有所不同。
确定 BMAT 组成对短期高卡路里喂养和禁食的反应。我们假设高喂养和热量限制会根据骨骼部位的不同而导致 BMAT 组成的差异。
我们检查了 23 名健康受试者（13 名男性，10 名女性，平均年龄 33±7 岁，BMI 26±1.5kg/m2），他们被收治入院进行为期 10 天的高热量逗留（热量摄入目标是增加 7%的体重），然后出院回家进行 13-18 天的正常饮食（稳定期），然后进行为期 10 天的禁食逗留（无热量摄入）。受试者在 3T 磁共振仪上接受腰椎（L4）（rBMAT）、股骨骨干和胫骨远端干骺端的单体素质子磁共振波谱（1H-MRS），以确定 BMAT 组成（不饱和指数，UI 和饱和度指数，SI）。采用 Wilcoxon 符号秩检验进行组内比较。
与基线相比，高卡路里访问后 L4 的 SI 增加（0.62±0.27 至 0.70±0.28，p=0.02），并且股骨 SI 和 UI 呈增加趋势（p≥0.07），而胫骨 BMAT 无明显变化（p≥0.13）。在稳定期，L4 的 SI 降低（0.70±0.28 至 0.57±0.21，p<0.0001），股骨骨干的 SI 降低（5.37±2.27 至 5.09±2.43，p=0.03），而 UI 或胫骨 BMAT 无明显变化（p≥0.14）。在禁食期，L4 的 SI 增加（0.57±0.21 至 0.63±0.30，p=0.03），而 UI 无变化（p=0.7）。股骨骨干的 SI 和 UI 降低（5.09±2.43 至 4.68±2.15，p=0.03，0.62±0.42 至 0.47±0.37，p=0.02），胫骨干骺端的 UI 降低（1.48±0.49 至 1.24±0.57，p=0.04）。
1H-MRS 能够在短期营养挑战期间定量 BMAT 组成，显示 rBMAT 的 SI 在高卡路里喂养期间显著增加，并且对禁食的反应不同，rBMAT 的 SI 增加，股骨 cBMAT 的 SI 和 UI 降低，胫骨 cBMAT 的 UI 降低。
