AIM： To assess the effectiveness of the current UK clinical practice in reducing hepatic fat （IHCL）.METHODS： Whole body MRI and IH MRS were obtained, before and after 6 mo nutritional counselling, from liver, sole...AIM： To assess the effectiveness of the current UK clinical practice in reducing hepatic fat （IHCL）.METHODS： Whole body MRI and IH MRS were obtained, before and after 6 mo nutritional counselling, from liver, soleus and tibialis muscles in 10 subjects with non-alcoholic fatty liver disease （NAFLD）.RESULTS： A 500 Kcal-restricted diet resulted in an average weight loss of 4% （-3.4 kg,） accompanied by significant reductions in most adipose tissue （AT） depots, including subcutaneous （-9.9%）, abdominal subcutaneous （-10.2%） and intra-abdominal- AT （-11.4%）. Intramyocellular lipids （IMCL） were significantly reduced in the tibialis muscle （-28.2%）. Decreases in both IHCL （-39.9%） and soleus IMCL （-12.2%） content were also observed, although these were not significant. Several individuals showed dramatic decreases in IHCL, while others paradoxically showed increases in IHCL content. Changes in body composition were accompanied by improvements in certain liver function tests： serum aspartate aminotransferase （AST） and alanine aminotransferase （ALT）. Significant correlations were found between decreases in IHCL and reductions in both intra-abdominal and abdominal subcutaneous AT. Improvements in liver function tests were associated with reductions in intra-abdominal AT, but not with changes in IHCL. CONCLUSION： This study shows that even a very modest reduction in body weight achieved through lifestyle modification can result in changes in body fat depots and improvements in LETs.展开更多
目的探讨影响腺苷酸激活蛋白激酶(AMP activated protein kinase,AMPK)/乙酰辅酶a羧化酶(acetyl Co A carboxylase,ACC)信号通路导致烧伤后骨骼肌脂质沉积(intramyocellular lipids,IMCLs)的分子机制。方法采用30%体表面积Ⅲ度烧伤小鼠...目的探讨影响腺苷酸激活蛋白激酶(AMP activated protein kinase,AMPK)/乙酰辅酶a羧化酶(acetyl Co A carboxylase,ACC)信号通路导致烧伤后骨骼肌脂质沉积(intramyocellular lipids,IMCLs)的分子机制。方法采用30%体表面积Ⅲ度烧伤小鼠模型,将54只BALB/c小鼠按随机数字表法分为正常对照组、AMPK激活剂(acadesine,AICAR)组、烧伤组、烧伤+AICAR组,同位素标记法检测各组小鼠腓肠肌中肉碱脂酰转移酶-1(carnitine palmitoyl transferase-1,CPT1)活性变化,Western blot检测各组小鼠腓肠肌中AMPK-α、p-AMPK-α、ACC及p-ACC表达水平,通过油红O染色和甘油三酯(triglyceride,TG)测定法评估各组小鼠腓肠肌IMCLs情况。结果烧伤后小鼠腓肠肌中ACC表达量较伤前显著升高(P<0.05),而AMPK-α、p-AMPK-α、p-ACC以及CPT1活性均显著降低(P<0.05)。在AICAR作用下,正常小鼠腓肠肌中p-AMPK-α表达显著升高[(1.16±0.08)vs(2.38±0.22),P<0.05],p-ACC表达显著升高[(1.74±0.10)vs(3.72±0.18),P<0.05],CPT1活性显著升高[(2.95±0.39)nmol/(min·mg)vs(6.35±0.68)nmol/(min·mg),P<0.05],TG含量显著降低[(3.88±0.40)mmol/g vs(2.89±0.54)mmol/g,P<0.05]。烧伤+AICAR组小鼠腓肠肌中p-AMPK-α、p-ACC、CPT1活性及甘油三酯含量较烧伤组无显著差异(P>0.05)。正常对照组和AICAR组正常小鼠腓肠肌组织切片油红O染色未见明显脂质沉积,而烧伤组和烧伤+AICAR组烧伤小鼠腓肠肌组织切片油红O染色均显示有大量脂质沉积,两组间并无显著差异(P>0.05)。结论骨骼肌中AMPK磷酸化障碍是烧伤后IMCLs的重要分子机制之一。展开更多
BACKGROUND Proton magnetic resonance spectroscopy(~1H MRS) is a technique widely used for investigating metabolites in humans. Lipids are stored outside the muscle cell are called extramyocellular lipids(EMCL), and li...BACKGROUND Proton magnetic resonance spectroscopy(~1H MRS) is a technique widely used for investigating metabolites in humans. Lipids are stored outside the muscle cell are called extramyocellular lipids(EMCL), and lipids stored on the inside of muscle cells are called intramyocellular lipids(IMCL). The relationship between metabolic syndrome and IMCL has been extensively studied.AIM To determine the effects of muscle fiber orientations on muscle metabolites using ~1H MRS.METHODS Chicken muscles were used as the subject in this study. MRS spectra were performed on a 1.5 T Magnetic resonance imaging machine(1.5 Tesla Philips Achieva). A single voxel(8 mm × 8 mm × 20 mm) was placed on the chicken extensor iliotibialis lateralis muscle with the muscle fiber oriented at 0°, 30°, 60°,and 90° to the main magnetic field. ~1H MRS spectra were acquired using a pointresolved spectroscopy, TR = 2000 ms, TE = 30 ms, and NSA = 256. Metabolites of interest from each orientation to the main magnetic field were compared using Wilcoxon signed-rank test. Differences less than 0.05 were considered to be statistically significant with 95%CI.RESULTS The metabolite profiles were different for each orientation of muscle fibers to the main magnetic field. The orientation at 90° was the most different compared to other orientations. The quantity of IMCL and EMCL exhibited statistically significantly changes with impacts at 30°, 60°, and 90° when compared with muscles aligned at 0° to the main magnetic field. Statistical analysis showed statistically significant IMCL(CH_3), EMCL(CH_3), and IMCL(CH_2) at 30°, 60°, and 90°(P = 0.017, 0.018, and 0.018, respectively) and EMCL(CH_2) at 30° and 60°(P =0.017 and 0.042, respectively). EMCL(CH_2) at 90° was unable to be measured in this study. The muscle lipids quantified at 30°, 60°, and 90° tended to be lower when compared to 0°.CONCLUSION Careful positioning is one of the most important factors to consider when studying ~1H MRS metabolites in muscles to ensure reproducibility and uniformity of muscle metabolite spectra.展开更多
基金Supported by the British Medical Research Council, United Kingdom, No. MRC CEG G99000178
文摘AIM： To assess the effectiveness of the current UK clinical practice in reducing hepatic fat （IHCL）.METHODS： Whole body MRI and IH MRS were obtained, before and after 6 mo nutritional counselling, from liver, soleus and tibialis muscles in 10 subjects with non-alcoholic fatty liver disease （NAFLD）.RESULTS： A 500 Kcal-restricted diet resulted in an average weight loss of 4% （-3.4 kg,） accompanied by significant reductions in most adipose tissue （AT） depots, including subcutaneous （-9.9%）, abdominal subcutaneous （-10.2%） and intra-abdominal- AT （-11.4%）. Intramyocellular lipids （IMCL） were significantly reduced in the tibialis muscle （-28.2%）. Decreases in both IHCL （-39.9%） and soleus IMCL （-12.2%） content were also observed, although these were not significant. Several individuals showed dramatic decreases in IHCL, while others paradoxically showed increases in IHCL content. Changes in body composition were accompanied by improvements in certain liver function tests： serum aspartate aminotransferase （AST） and alanine aminotransferase （ALT）. Significant correlations were found between decreases in IHCL and reductions in both intra-abdominal and abdominal subcutaneous AT. Improvements in liver function tests were associated with reductions in intra-abdominal AT, but not with changes in IHCL. CONCLUSION： This study shows that even a very modest reduction in body weight achieved through lifestyle modification can result in changes in body fat depots and improvements in LETs.
文摘目的探讨影响腺苷酸激活蛋白激酶(AMP activated protein kinase,AMPK)/乙酰辅酶a羧化酶(acetyl Co A carboxylase,ACC)信号通路导致烧伤后骨骼肌脂质沉积(intramyocellular lipids,IMCLs)的分子机制。方法采用30%体表面积Ⅲ度烧伤小鼠模型,将54只BALB/c小鼠按随机数字表法分为正常对照组、AMPK激活剂(acadesine,AICAR)组、烧伤组、烧伤+AICAR组,同位素标记法检测各组小鼠腓肠肌中肉碱脂酰转移酶-1(carnitine palmitoyl transferase-1,CPT1)活性变化,Western blot检测各组小鼠腓肠肌中AMPK-α、p-AMPK-α、ACC及p-ACC表达水平,通过油红O染色和甘油三酯(triglyceride,TG)测定法评估各组小鼠腓肠肌IMCLs情况。结果烧伤后小鼠腓肠肌中ACC表达量较伤前显著升高(P<0.05),而AMPK-α、p-AMPK-α、p-ACC以及CPT1活性均显著降低(P<0.05)。在AICAR作用下,正常小鼠腓肠肌中p-AMPK-α表达显著升高[(1.16±0.08)vs(2.38±0.22),P<0.05],p-ACC表达显著升高[(1.74±0.10)vs(3.72±0.18),P<0.05],CPT1活性显著升高[(2.95±0.39)nmol/(min·mg)vs(6.35±0.68)nmol/(min·mg),P<0.05],TG含量显著降低[(3.88±0.40)mmol/g vs(2.89±0.54)mmol/g,P<0.05]。烧伤+AICAR组小鼠腓肠肌中p-AMPK-α、p-ACC、CPT1活性及甘油三酯含量较烧伤组无显著差异(P>0.05)。正常对照组和AICAR组正常小鼠腓肠肌组织切片油红O染色未见明显脂质沉积,而烧伤组和烧伤+AICAR组烧伤小鼠腓肠肌组织切片油红O染色均显示有大量脂质沉积,两组间并无显著差异(P>0.05)。结论骨骼肌中AMPK磷酸化障碍是烧伤后IMCLs的重要分子机制之一。
基金Supported by Department of Radiologic Technology,Faculty of Associated Medical Sciences,Chiang Mai University,Thailand
文摘BACKGROUND Proton magnetic resonance spectroscopy(~1H MRS) is a technique widely used for investigating metabolites in humans. Lipids are stored outside the muscle cell are called extramyocellular lipids(EMCL), and lipids stored on the inside of muscle cells are called intramyocellular lipids(IMCL). The relationship between metabolic syndrome and IMCL has been extensively studied.AIM To determine the effects of muscle fiber orientations on muscle metabolites using ~1H MRS.METHODS Chicken muscles were used as the subject in this study. MRS spectra were performed on a 1.5 T Magnetic resonance imaging machine(1.5 Tesla Philips Achieva). A single voxel(8 mm × 8 mm × 20 mm) was placed on the chicken extensor iliotibialis lateralis muscle with the muscle fiber oriented at 0°, 30°, 60°,and 90° to the main magnetic field. ~1H MRS spectra were acquired using a pointresolved spectroscopy, TR = 2000 ms, TE = 30 ms, and NSA = 256. Metabolites of interest from each orientation to the main magnetic field were compared using Wilcoxon signed-rank test. Differences less than 0.05 were considered to be statistically significant with 95%CI.RESULTS The metabolite profiles were different for each orientation of muscle fibers to the main magnetic field. The orientation at 90° was the most different compared to other orientations. The quantity of IMCL and EMCL exhibited statistically significantly changes with impacts at 30°, 60°, and 90° when compared with muscles aligned at 0° to the main magnetic field. Statistical analysis showed statistically significant IMCL(CH_3), EMCL(CH_3), and IMCL(CH_2) at 30°, 60°, and 90°(P = 0.017, 0.018, and 0.018, respectively) and EMCL(CH_2) at 30° and 60°(P =0.017 and 0.042, respectively). EMCL(CH_2) at 90° was unable to be measured in this study. The muscle lipids quantified at 30°, 60°, and 90° tended to be lower when compared to 0°.CONCLUSION Careful positioning is one of the most important factors to consider when studying ~1H MRS metabolites in muscles to ensure reproducibility and uniformity of muscle metabolite spectra.
