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Assessment of Changes in Metabolic Activity in Liver & Skeletal Muscle in Patients Suffering From Acromegaly

2016年9月26日 更新者：Prof. Dr. Michael Krebs、Medical University of Vienna

Assessment of Changes in Metabolic Activity in Liver & Skeletal Muscle in Patients Suffering From Acromegaly - a 31P/1H Magnetic Resonance Spectroscopy Pilot Study

Growth hormone (GH) plays a pivotal role in the regulation of body composition including ectopic lipid deposition in insulin sensitive organs like liver and skeletal muscle. Recent evidence indicates that the GH-IGF1 axis affects body composition via regulating mitochondrial oxidation capacity.

Thus, excessive GH secretion by a pituitary adenoma (Acromegaly) might be accompanied by increased mitochondrial activity leading to inappropriately low intracellular lipid depots, especially in metabolically active tissue like liver and skeletal muscle.

This study aims to assess metabolic activity and intracellular lipid content in skeletal muscle and liver in patients suffering from acromegaly compared to controls by 31P/1H Magnetic resonance spectroscopy before and in follow up examinations 3, 6 and 12 months after initiation of GH lowering treatments including surgery, somatostatinanalogs or pegvisomant, as well as oral glucose tolerance tests at each examination to assess treatment responses and calculate validated parameters for insulin sensitivity and resistance.

調査の概要

状態

わからない

条件

介入・治療

詳細な説明

Background: Growth hormone (GH) plays a pivotal role in the regulation of body composition including ectopic lipid deposition in insulin sensitive organs like liver and skeletal muscle. Direct inhibition of growth hormone action by a receptor antagonist has been shown to induce hepatic steatosis and growth hormone replacement decreases liver fat content in obese humans. Of note, recent evidence indicates that the GH-IGF1 axis affects body composition via regulating mitochondrial oxidation capacity.

Hypothesis: Direct and/or indirect effects of GH on mitochondrial function might mediate the changes in body composition and lipid deposition. Thus, excessive GH secretion by a pituitary adenoma (Acromegaly) might be accompanied by increased mitochondrial activity leading to inappropriately low intracellular lipid depots, especially in metabolically active tissue like liver and skeletal muscle.

Aim: Assessment of metabolic activity and intracellular lipid content in skeletal muscle and liver in patients suffering from acromegaly compared to controls.

Methods: Non-interventional study:

  • 31P/1H Magnetic resonance spectroscopy before and in follow up examinations 3, 6 and 12 months after initiation of GH lowering treatments including surgery, somatostatinanalogs or pegvisomant.
  • oral glucose tolerance tests at each examination to assess treatment responses and calculate validated parameters for insulin sensitivity and resistance.

研究の種類

観察的

入学 (予想される)

24

連絡先と場所

このセクションには、調査を実施する担当者の連絡先の詳細と、この調査が実施されている場所に関する情報が記載されています。

研究場所

  • オーストリア
      • Vienna、オーストリア、1090
        • 募集
        • Medical University of Vienna, Department of Internal Medicine III
        • コンタクト：
        • 主任研究者：
          • Michael Krebs, MD, Prof

参加基準

研究者は、適格基準と呼ばれる特定の説明に適合する人を探します。これらの基準のいくつかの例は、人の一般的な健康状態または以前の治療です。

適格基準

就学可能な年齢

18年～75年 (大人、高齢者)

健康ボランティアの受け入れ

いいえ

受講資格のある性別

全て

サンプリング方法

非確率サンプル

調査対象母集団

acromegalic patients and healthy controls matched for sex, age and body mass index

説明

Inclusion Criteria:

  • age between 18-75 years

Exclusion Criteria:

  • (known) overt diabetes mellitus
  • known coronary artery disease (history of myocardial infarction or angina pectoris)
  • acute or chronic (inflammatory, metabolic [hyperlipidemia, arterial hypertension, thyroid disorder]) disease (healthy controls)
  • intake of medication potentially affecting glucose or lipid metabolism
  • metal devices or other magnetic material in or on the subjects body which will be hazardous for NMR investigation [heart pacemaker, brain (aneurysm) clip, nerve stimulators, electrodes, ear implants, post coronary by-pass graft (epicardial pace wires), penile implants, colored contact lenses, patch to deliver medications through the skin, coiled spring intrauterine device, vascular filter for blood clots, orthodontic braces, shunt- spinal or ventricular, any metal implants (rods, joints, plates, pins, screws, nails, or clips without MR-authorization), embolization coil, or any metal fragments or shrapnel in the body].
  • tendency toward claustrophobia
  • severe liver disorders (plasma transaminases elevated > 3fold)
  • any acute inflammatory disease within 2 weeks prior the study
  • pregnancy
  • nursing
  • clinically relevant anemia

研究計画

このセクションでは、研究がどのように設計され、研究が何を測定しているかなど、研究計画の詳細を提供します。

研究はどのように設計されていますか？

デザインの詳細

  • 観測モデル：ケースコントロール
  • 時間の展望：見込みのある

コホートと介入

グループ/コホート
介入・治療
Acromegalic patients
Acromegalic patients before and after initiation of individual therapy will be investigated by 1H/31P magnetic resonance spectroscopy, thyroid sonography and oral glucose tolerance testing
他の：1H/31P Magnetic Resonance Spectroscopy
The 31P-MRS examinations will be performed in a 7 T MR system (Siemens Healthcare, Erlangen, Germany) using a double-tuned (31P/1H) surface coil (Rapid Biomedical Ltd, Rimpar, Germany), with a diameter of 10 cm. Participants will be investigated lying in lateral position with the right lobe of the liver positioned over the coil.
他の：oral glucose tolerance testing

In patients without overt diabetes, glucose tolerance will be assessed by an oral glucose tolerance test, routinely performed at the outpatients clinic. The test will be performed in the morning after an overnight fast of at least 8 hours. Blood will be drawn via a catheter placed in an antecubital vein of one arm. Blood samples for the assessment of glucose, insulin, C-peptide, free fatty acids and growth hormone will be drawn at baseline as well as 30, 60, 90 and 120 minutes after ingestion of 75g glucose in a solution.

Concentrations of glucose, insulin and C-peptide will be used to derive parameters of insulin secretion and insulin sensitivity by mathematical modelling.

他の：Thyroid sonography
In acromegalic patients thyroid morphology will be assessed at the outpatient clinic of the Division of Endocrinology and Metabolism, using standard ultrasound technique. Measurements will be performed by a well- experienced physician at baseline and at each follow up examination in an out-patient care setting.
Healthy control subjects
Age and Body mass index matched control subjects will be investigated by 1H/31P magnetic resonance spectroscopy and oral glucose tolerance testing
他の：1H/31P Magnetic Resonance Spectroscopy
The 31P-MRS examinations will be performed in a 7 T MR system (Siemens Healthcare, Erlangen, Germany) using a double-tuned (31P/1H) surface coil (Rapid Biomedical Ltd, Rimpar, Germany), with a diameter of 10 cm. Participants will be investigated lying in lateral position with the right lobe of the liver positioned over the coil.
他の：oral glucose tolerance testing

In patients without overt diabetes, glucose tolerance will be assessed by an oral glucose tolerance test, routinely performed at the outpatients clinic. The test will be performed in the morning after an overnight fast of at least 8 hours. Blood will be drawn via a catheter placed in an antecubital vein of one arm. Blood samples for the assessment of glucose, insulin, C-peptide, free fatty acids and growth hormone will be drawn at baseline as well as 30, 60, 90 and 120 minutes after ingestion of 75g glucose in a solution.

Concentrations of glucose, insulin and C-peptide will be used to derive parameters of insulin secretion and insulin sensitivity by mathematical modelling.

この研究は何を測定していますか？

主要な結果の測定

結果測定
メジャーの説明
時間枠
Changes in hepatic energy metabolism
時間枠：before & 3,6,9, and 12 months after initiation of therapy
The 31P-MRS examinations will be performed in a 7 T MR system (Siemens Healthcare, Erlangen, Germany) using a double-tuned (31P/1H) surface coil (Rapid Biomedical Ltd, Rimpar, Germany), with a diameter of 10 cm.
before & 3,6,9, and 12 months after initiation of therapy

二次結果の測定

結果測定
メジャーの説明
時間枠
Changes in hepatic lipid content
時間枠：before, as well as 3,6,9 &12 months after initiation of therapy
Hepatic lipid content will be assessed using localized single voxel 1H MRS as published by our study group. STEAM sequence (VOI= 3×3×3 cm3; TE= 30, 50, 70, 120 ms; NA= 4 for each TE) data acquisition will be performed during repetitive single breath holds. Hepatocellular lipid (HCL) content will be calculated from ration of summed area of methylene and methyl resonance to that of water following the individual spin-spin relaxation correction as per cent of total tissue MRS signal (water + methylene + methyl).
before, as well as 3,6,9 &12 months after initiation of therapy

その他の成果指標

結果測定
メジャーの説明
時間枠
Changes in skeletal muscle energy metabolism
時間枠：before, as well as 3,6,9 and 12 months after initiation of therapy
Resting-state ATP turnover will be measured using a ST experiment. The subjects will be lying in a supine position with the surface coil fixed underneath the right calf muscle. Baseline intramyocellular concentrations of phosphorous metabolites will be assessed based on T1 corrected partially relaxed baseline spectra (TR, 15 s; 16 averages). The exchange between γ-ATP and PCr (i.e., CK reaction), and between γ-ATP and Pi (i.e., ATP- synthesis) will be investigated.
before, as well as 3,6,9 and 12 months after initiation of therapy
Changes in skeletal muscle lipid content
時間枠：before, as well as 3,6,9 and 12 months after initiation of therapy
Intramyocellular lipid content will be assessed using localized single voxel 1H MRS as published by our studygroup[34]. STEAM sequence (VOI= 12x12x12 mm3; TE= 20 ms; TR= 4 sec, NA= 16) data acquisition will be performed in two volumes of interest positioned in soleus and tibialis anterior muscle. Separate spectra without water signal suppression (NA= 4) will be obtained from both muscle groups. Intramyocellular lipid content (IMCL) content will be calculated from ratio of area of methylene (1.25 ppm) to that of water following the individual spin-spin relaxation correction as per cent of tissue water MRS signal.
before, as well as 3,6,9 and 12 months after initiation of therapy
Changes in thyroid morphology
時間枠：before and 12 months after initiation of individual therapy
In acromegalic patients thyroid morphology will be assessed at the outpatient clinic of the Division of Endocrinology and Metabolism, using standard ultrasound technique. Measurements will be performed by a well- experienced physician at baseline and at each follow up examination in an out-patient care setting.
before and 12 months after initiation of individual therapy

協力者と研究者

ここでは、この調査に関係する人々や組織を見つけることができます。

スポンサー

Medical University of Vienna

捜査官

  • 主任研究者：Michael Krebs, MD, Prof.、Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria

出版物と役立つリンク

研究に関する情報を入力する責任者は、自発的にこれらの出版物を提供します。これらは、研究に関連するあらゆるものに関するものである可能性があります。

一般刊行物

研究記録日

これらの日付は、ClinicalTrials.gov への研究記録と要約結果の提出の進捗状況を追跡します。研究記録と報告された結果は、国立医学図書館 (NLM) によって審査され、公開 Web サイトに掲載される前に、特定の品質管理基準を満たしていることが確認されます。

主要日程の研究

研究開始

2014年8月1日

一次修了 (予想される)

2017年5月1日

研究の完了 (予想される)

2018年5月1日

試験登録日

最初に提出

2014年4月11日

QC基準を満たした最初の提出物

2014年4月15日

最初の投稿 (見積もり)

2014年4月16日

学習記録の更新

投稿された最後の更新 (見積もり)

2016年9月27日

QC基準を満たした最後の更新が送信されました

2016年9月26日

最終確認日

2016年9月1日

詳しくは

本研究に関する用語

追加の関連 MeSH 用語

その他の研究ID番号

  • THIGHT_2

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