Mechanisms Underlying Metabolic Syndrome in Obesity
研究概览
详细说明
Obesity is the most common and powerful force for creating insulin resistance and metabolic syndrome, however, the molecular basis of this association is not well understood. In this proposal, three independently funded researchers-Philip Kern, MD a clinical investigator, and Charlotte Peterson, PhD and Robert McGehee, PhD, with significant experience in muscle and adipocyte biology, respectively-will formalize a collaborative effort as a natural extension of previous work and shared interests in the fields of obesity, insulin resistance, and tissue lipid accumulation. Our overall hypothesis is that insulin resistance in humans stems largely from ectopic accumulation of intramyocellular lipid (IMCL) during the development of obesity. Further, we hypothesize that excess IMCL accumulation is dependent on secretory proteins derived from a complex interplay between adipocytes and macrophages in adipose tissue. To test these hypotheses, we will examine the interactions among adipocytes, macrophages, and muscle cells isolated and cultured from subjects that are obese with insulin resistance and impaired glucose tolerance (IGT), and from some with Type 2 Diabetes. This study population has elevated IMCL and is at high risk for obesity complications, but avoids the pathophysiologic complications of glucotoxicity. These subjects will be compared to obese subjects with normal glucose tolerance (NGT).
Aim 1 will explore mechanisms that contribute to IMCL and elucidate its role in the development of IGT. Cultured muscle cells will be used to determine whether obese subjects with IGT versus NGT demonstrate intrinsic differences in muscle gene expression and metabolic activity under differing extracellular fatty acid concentrations. Lipid accumulation and oxidation, and insulin-mediated glycogen synthesis and signaling will be assessed.
Aim 2 will determine if the IMCL accumulation is dependent on adipose tissue secretory proteins. We will use co-cultures of adipocytes, myoblasts, and adipose stromal vascular cells to examine IMCL and the development of insulin resistance.
Aim 3 will determine whether the stromal fraction from IGT subjects promotes IMCL more effectively than that from NGT subjects in co-cultures with muscle cells. We will compare the stromal vascular fractions with regard to monocyte/macrophage accumulation and cytokine expression.
Aim 4 will determine if improved glucose tolerance in response to a 10-week treatment with pioglitazone results in decreased IMCL and identify cellular mechanisms involved. Co-culture studies will also be used with muscle and stromal cells, before and after pioglitazone treatment. These experiments will provide mechanistic insight into the link between obesity and muscle function leading to metabolic syndrome.
研究类型
注册 (实际的)
阶段
- 第四阶段
联系人和位置
学习地点
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Arkansas
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Little Rock、Arkansas、美国、72205
- University of Arkansas for Medical Sciences
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Kentucky
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Lexington、Kentucky、美国、40536
- University of Kentucky
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参与标准
资格标准
适合学习的年龄
接受健康志愿者
有资格学习的性别
描述
Inclusion Criteria:
- 18-65 years of age
- BMI 28+
- diabetes, impaired glucose tolerance or normal glucose tolerance
Exclusion Criteria:
- AST >2x normal
- congestive heart failure
- history of coronary artery disease
- chronic renal insufficiency (creatinine > 1.4mg/dl)
- use of gemfibrozil, ACE inhibitors, and angiotensin receptor II blockers, or anticoagulants
学习计划
研究是如何设计的?
设计细节
- 主要用途:基础科学
- 分配:非随机化
- 介入模型:单组作业
- 屏蔽:无(打开标签)
武器和干预
参与者组/臂 |
干预/治疗 |
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无干预:1
Baseline studies (OGTT, DXA, RMR, FSIGT, and biopsies) on normal control subjects.
Oral glucose tolerance tests, body composition assessment, resting metabolic rate, insulin sensitivity measurement with the frequently sampled method and Minimal Model.
These studies will establish baseline data in lean subjects on adipose tissue gene expression, insulin sensitivity, glucose tolerance, metabolic rate and body composition.
There is no intervention.
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有源比较器:2
Baseline studies (OGTT, DXA, RMR, FSIGT, biopsies), then 10 weeks treatment on Pioglitazone.
Baseline tests are repeated at the end of medication treatment.
All of the studies described in arm 1 are repeated after treatment.
The subjects in this group have impaired glucose tolerance.
After the measurement of adipose tissue gene expression, insulin sensitivity, glucose tolerance, metabolic rate and body composition, subjects are treated with pioglitazone, working up to 45 mg/day, for 10 weeks.
After this time, adipose tissue gene expression, insulin sensitivity, glucose tolerance, metabolic rate and body composition are repeated.
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Pioglitazone 30mg for 2 weeks, then Pioglitazone 45mg for 8 weeks.
其他名称:
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研究衡量的是什么?
主要结果指标
结果测量 |
措施说明 |
大体时间 |
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Change in Insulin Sensitivity Using FSIGT
大体时间:Baseline and 10 weeks
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The frequently sampled intravenous glucose tolerance test (FSIGT) involves the injection of IV glucose and the frequent measurement of glucose and insulin.
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Baseline and 10 weeks
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Effects of Pioglitazone on Changes in BMI
大体时间:Baseline and 10 weeks
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Body Mass Index (BMI) is measured at baseline, in lean and obese subjects, and after pioglitazone in obese subjects
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Baseline and 10 weeks
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Changes in Muscle Lipid After Pioglitazone
大体时间:At baseline and 10 weeks
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Muscle lipid following biopsy using oil red-O staining.
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At baseline and 10 weeks
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Changes in Fat Inflammation Following Pioglitazone
大体时间:Baseline and 10 weeks
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macrophages in fat at baseline, in lean and obese participants, and obese after pioglitazone (in obese)
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Baseline and 10 weeks
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合作者和调查者
赞助
合作者
调查人员
- 首席研究员:Philip Kern, MD、University of Kentucky
研究记录日期
研究主要日期
学习开始
初级完成 (实际的)
研究完成 (实际的)
研究注册日期
首次提交
首先提交符合 QC 标准的
首次发布 (估计)
研究记录更新
最后更新发布 (实际的)
上次提交的符合 QC 标准的更新
最后验证
更多信息
与本研究相关的术语
其他研究编号
- 32677
- R01DK071277 (美国 NIH 拨款/合同)
计划个人参与者数据 (IPD)
计划共享个人参与者数据 (IPD)?
IPD 计划说明
药物和器械信息、研究文件
研究美国 FDA 监管的药品
研究美国 FDA 监管的设备产品
在美国制造并从美国出口的产品
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代谢综合征的临床试验
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Sanford HealthNational Ataxia Foundation; Beyond Batten Disease Foundation; Pitt Hopkins Research Foundation; Cornelia... 和其他合作者招聘中线粒体疾病 | 色素性视网膜炎 | 重症肌无力 | 嗜酸性胃肠炎 | 多系统萎缩 | 平滑肌肉瘤 | 脑白质营养不良 | 肛瘘 | 脊髓小脑性共济失调3型 | 弗里德赖希共济失调 | 肯尼迪病 | 莱姆病 | 噬血细胞性淋巴组织细胞增生症 | 脊髓小脑性共济失调1型 | 脊髓小脑性共济失调2型 | 脊髓小脑共济失调6型 | 威廉姆斯综合症 | 先天性巨结肠症 | 糖原贮积病 | 川崎病 | 短肠综合症 | 低磷血症 | Leber先天性黑蒙 | 口臭 | 贲门失弛缓症 | 多发性内分泌肿瘤 | 利综合症 | 艾迪生病 | 多发性内分泌肿瘤 2 型 | 硬皮病 | 多发性内分泌肿瘤 1 型 | 多发性内分泌肿瘤 2A 型 | 多发性内分泌肿瘤 2B 型 | 非典型溶血性尿毒症综合征 | 胆道闭锁 | 痉挛性共济失调 | WAGR综合症 | 无虹膜 | 短暂性失忆症 | 马尾综合症 | Refsum 疾病 | 复发性呼吸... 及其他条件美国, 澳大利亚