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Regression of Fatty Heart by Valsartan Therapy

16. januar 2019 opdateret af: University of Texas Southwestern Medical Center

Traditionally, obesity is considered an indirect cause of heart disease. Obese individuals typically present with a number of traditional Framingham risk factors (hypertension, dyslipidemia, and type 2 diabetes), predisposing them to heart attacks and subsequent heart failure. However, an emerging body of basic research revisits a hypothesis that fat is a direct cardiotoxin. Under healthy conditions, most triglyceride is stored in fatty tissue (adipocytes) while the amount of triglyceride stored in non-adipocyte tissues (such as the pancreas, the liver, skeletal muscle, and heart) is minimal and very tightly regulated. When this regulation is disrupted, intracellular triglyceride accumulates excessively in these organs ("steatosis") and has been implicated in activating adverse pathways which culminate in irreversible cell death ("lipotoxicity"), leading to several well-recognized clinical syndromes. These include non-alcoholic steatohepatitis (NASH), pancreatic beta-cell failure in type 2 diabetes, and dilated cardiomyopathy.

It has been recently observed that angiotensin II receptor blockers (ARBs) in addition to lowering blood pressure improve insulin sensitivity and decrease the risk for type 2 diabetes. This study will test the above theory in two study groups: Valsartan vs. Hydrochlorothiazide. We hypothesize that in obese humans with elevated myocardial triglycerides, blockade of the renin-angiotensin system (Valsartan group) will reduce myocardial fat with improvement of insulin sensitivity and heart function.

Studieoversigt

Status

Trukket tilbage

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

Basic science in animal models of genetic obesity have demonstrated that obese, insulin resistant animals have fatty hearts with reduced functional ability. More importantly, insulin sensitizing treatment of prediabetic rats delayed development of diabetes and improved heart function. A primary aim of our laboratory is to translate basic animal research, suggesting that excessive lipid accumulation in the myocardium is toxic, into the clinical setting using cardiac magnetic resonance imaging/spectroscopy technology. The results of this research may identify new biomarkers and drug targets to prevent cardiac disease in obese humans.

We used our novel in vivo magnetic resonance imaging and spectroscopy technique that enables quantification of triglyceride in human myocardium non-invasively, to demonstrate that obese humans like obese animals are characterized by elevated fat in myocardium. We hypothesize that in obese humans with elevated myocardial TG, blockade of the renin-angiotensin system will reduce myocardial fat with improvement of insulin sensitivity and heart function.

The aims of this study are to test if in obese people with impaired glucose tolerance (IGT):

Aim 1) Valsartan treatment will reduce myocardial fat and will improve heart geometry and function,

Aim 2) therapy with thiazide diuretic hydrochlorothiazide (HCTZ) treatment will elevate myocardial fat.

We are planning to test the action of Valsartan versus HCTZ as we expect that these drugs cause opposite metabolic effects. The landmark trial ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) has refocused attention to the thiazide-type diuretics as the first-line therapy for most patients with hypertension. Despite proven reduction in cardiovascular outcomes and low costs, there is on-going concern that one of the major side effect of the thiazides-glucose intolerance-may fuel the current U.S. epidemic of type 2 diabetes. Despite of efficacy and low cost thiazide diuretics are long known to cause insulin resistance, impaired glucose tolerance, and precipitation of overt diabetes.

Undersøgelsestype

Interventionel

Fase

  • Fase 4

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiesteder

  • Forenede Stater
    • Texas
      • Dallas, Texas, Forenede Stater, 75390
        • University of Texas Southwestern Medical Center

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

18 år til 50 år (Voksen)

Tager imod sunde frivillige

Ingen

Køn, der er berettiget til at studere

Alle

Beskrivelse

Inclusion Criteria:

  • Prediabetic individuals with impaired glucose tolerance (2 hr postprandial glucose > 140mg/dL) or having 3 of 5 Metabolic Syndrome criteria:

    1. Fasting glucose > 100mg/dL;
    2. Waist circumference: men > 102cm, women > 88cm (confirmed with abdominal MRI);
    3. HDL: men < 40mg/dL, women < 50mg/dL;
    4. Triglycerides > 150mg/dL;
    5. Blood pressure > 130/80mmHg;
  • Elevated hepatic triglycerides (>5.5%) and myocardial triglycerides (>0.6%)
  • Elevated blood triglycerides >150mg/dL
  • Age < 50 years

Exclusion Criteria:

  • Type 2 Diabetes mellitus
  • Prior exposure to renin system blockers or HCTZ
  • BP > 160/100mmHg
  • Claustrophobia
  • Metallic implants in body
  • Pregnant or planning to become pregnant
  • Prior exposure to statin medications

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Behandling
  • Tildeling: Randomiseret
  • Interventionel model: Parallel tildeling
  • Maskning: Firedobbelt

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Aktiv komparator: Valsartan
This arm will determine if blockade of the renin-angiotensin system reduces myocardial fat levels and improves insulin sensitivity. It consists of 6 visits: visit1 (baseline); visit2 (2 weeks); visit3 (1 month); visit4 (3 month); visit5 (6 month); visit6 (8 month). Visits 1 & 6 will consist of blood tests, glucose tolerance test by FSivGTT, MRS, & 24 hr ambulatory blood pressure monitoring. During visit 1, patients receive automatic blood pressure monitor, OMRON, to record blood pressure between visits. Visits 2 & 3 are needed for the adjustment of medication to the final dose level. During visits 4 & 5, Dr. Price will check subject's status as they continue the medication. In case of uncontrolled blood pressure, Dr. Price will prescribe amlodipine for the additional BP control.
Medicin: Valsartan
Valsartan 320mg PO daily for 8 months
Andre navne:
  • Diovan
Aktiv komparator: Hydrochlorothiazide
This arm will determine if thiazide diuretics elevate myocardial triglyceride levels. It consists of 6 visits: visit1 (baseline); visit2 (2 weeks); visit3 (1 month); visit4 (3 month); visit5 (6 month); visit6 (8 month). Visits 1 & 6 will consist of blood tests, glucose tolerance test by FSivGTT, MRS, & 24 hr ambulatory blood pressure monitoring. During visit 1, patients receive automatic blood pressure monitor, OMRON, to record blood pressure between visits. Visits 2 & 3 are needed for the adjustment of medication to the final dose level. During visits 4 & 5, Dr. Price will check subject's status as they continue the medication. In case of uncontrolled blood pressure, Dr. Price will prescribe amlodipine for the additional BP control.
Medicin: Hydrochlorothiazide
Hydrochlorothiazide 25mg PO daily for 8 months
Andre navne:
  • HCTZ

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Tidsramme
Myocardial triglyceride levels
Tidsramme: 8 months
8 months

Sekundære resultatmål

Resultatmål
Tidsramme
Hepatic triglyceride levels, insulin sensitivity, abdominal fat mass
Tidsramme: 8 months
8 months

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

University of Texas Southwestern Medical Center

Samarbejdspartnere

Novartis Pharmaceuticals

Efterforskere

  • Ledende efterforsker: Ronald G Victor, MD, University of Texas Southwestern Medical Center
  • Studieleder: Lidia S Szczepaniak, PhD, University of Texas Southwestern Medical Center

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart

1. august 2007

Primær færdiggørelse (Forventet)

1. august 2009

Studieafslutning (Forventet)

1. august 2009

Datoer for studieregistrering

Først indsendt

29. august 2008

Først indsendt, der opfyldte QC-kriterier

2. september 2008

Først opslået (Skøn)

3. september 2008

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

17. januar 2019

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

16. januar 2019

Sidst verificeret

1. januar 2019

Mere information

Begreber relateret til denne undersøgelse

Nøgleord

Yderligere relevante MeSH-vilkår

Andre undersøgelses-id-numre

  • IIRP Study US 73

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