Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore; Institute of Geriatrics and Active Ageing, Tan Tock Seng Hospital, Singapore.
Geriatric Education and Research Institute, Singapore.
Arch Gerontol Geriatr. 2019 Mar-Apr;81:1-7. doi: 10.1016/j.archger.2018.11.006. Epub 2018 Nov 13.
The presence of concomitant sarcopenia and obesity in sarcopenic obesity (SO) confers worse functional, morbidity and mortality outcomes compared to either alone. Excess adiposity and central redistribution of fats are associated with systemic inflammation and ectopic tissue fat infiltration in forms of Intermuscular adipose tissue (IMAT). Our study examines the profile of IMAT across a spectrum of body compositions and associations with physical performance and inflammatory biomarkers including Monocyte Chemoattractant Protein-1 (MCP-1), a novel biomarker of adipose tissue inflammation.
187 community dwelling elderly participants were recruited and classified into 4 subgroups: normal, obese, sarcopenia and SO, using validated criteria for sarcopenia and waist circumference to define central obesity. We performed magnetic resonance imaging of mid-thigh sections to segment IMAT and muscle. Participants were assessed for muscle strength, physical performance and blood inflammatory biomarkers of interleukin-6, C-Reactive Protein and MCP-1. We examined correlation of IMAT(ratio) with muscle function measures and blood biomarkers. Multiple regression analyses were used to examine the association of body composition types and IMAT(ratio) with muscle function.
IMAT(ratio) was highest in SO and obese groups. Overall, higher IMAT(ratio) is significantly associated with raised MCP-1, lower gait speed and muscle strength. SO had lowest scores in Short Physical Performance Battery (SPPB), gait speed, hand-grip and knee extension strength. IMAT(ratio) is independently associated with SPPB and handgrip strength, whilst SO is independently associated with muscle strength.
Our results suggest the possible role of IMAT as a candidate imaging biomarker for adipose tissue inflammation and associated poorer functional outcomes in SO.
与单独存在相比，在肌少症性肥胖（SO）中同时存在肌肉减少症和肥胖会导致更差的功能、发病率和死亡率结局。过多的脂肪和脂肪在中央的重新分布与全身炎症和肌间脂肪组织（IMAT）等异位组织脂肪浸润有关。我们的研究检查了 IMAT 在一系列身体成分中的分布情况，以及与身体表现和炎症生物标志物（包括单核细胞趋化蛋白-1（MCP-1），一种新的脂肪组织炎症生物标志物）的关联。
我们招募了 187 名居住在社区的老年参与者，并使用肌少症和腰围的验证标准将他们分为 4 个亚组：正常、肥胖、肌少症和 SO。我们对大腿中段进行磁共振成像，以分割 IMAT 和肌肉。对参与者进行肌肉力量、身体表现和白细胞介素-6、C 反应蛋白和 MCP-1 等血液炎症生物标志物的评估。我们检查了 IMAT（比率）与肌肉功能测量和血液生物标志物的相关性。多元回归分析用于检查身体成分类型和 IMAT（比率）与肌肉功能的关联。
SO 和肥胖组的 IMAT（比率）最高。总体而言，IMAT（比率）越高，MCP-1 越高，步态速度和肌肉力量越低。SO 在短体表现电池（SPPB）、步态速度、手握力和膝关节伸展力量方面得分最低。IMAT（比率）与 SPPB 和手握力独立相关，而 SO 与肌肉力量独立相关。
我们的结果表明，IMAT 可能是脂肪组织炎症和 SO 相关较差功能结局的候选成像生物标志物。
