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Completed

NCT Number: NCT01938521

Effects of Red Grape Cells (RGC) Powder in Type 2 Diabetics

The aim of this study is to examine whether the chronic administration during 12 weeks of polyphenols contained in Red Grape Cells (RGC) powder has an effect on mRNA expression of SIRT1 and Clock Genes, on circulating levels of HbA1c, lipids, blood pressure and on postprandial response of glucose, lipids, insulin, C-peptide and GLP-1 in patients with type 2 diabetes .

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Key information

Age range

30 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Daniela Jakubowicz MD

Holon, Tel Aviv, 58100, Israel

About this study

There is a growing body of evidence demonstrating that polyphenols and specially the most investigated Resveratrol contained in the Red Grape Cells (RGC) exert beneficial effects on several markers of metabolic syndrome i.e. antioxidant, anti-inflammatory, anti-atherosclerotic, vasodilator and antihypertensive activity.

Many of this beneficial metabolic effects of polyphenols, occurs via activation of sirtuin-1 or silent information regulator-1 gene (SIRT1). This gene is expressed in adipose tissue, muscle, endothelium, peripheral blood cells, etc where it plays a pivotal role in the regulation of Circadian Clock Genes (CCG) involved in glucose lipid metabolism, endothelial function, etc .

By activation of SIRT1 and CCG the polyphenols, may influence the circadian secretion of adiponectin, insulin, asymmetric dimethylarginine (ADMA) and other hormones that influence insulin sensitivity, muscular glucose uptake, NO synthesis, nocturnal hepatic glucose production, lipolisis and endothelial function It was shown in several studies in animals and in clinical studies in subjects with metabolic syndrome that SIRT1 expression and its regulation of the CCG, improves insulin sensitivity in skeletal muscle, preventing weight gain; improves pancreatic beta-cell function enhancing insulin secretion and glucose tolerance. It was associated with increased lipolisis in white adipose tissue, decreased glycolysis, increased fatty acid oxidation in skeletal muscle and with increase Nitric Oxide in the endothelium.

Given that polyphenols directly on the clock genes or by enhancing SIRT1 expression appears to counter some of the effects of a high-fat diet, obesity and metabolic syndrome, by protecting against insulin resistance, hyperglycemia, and dyslipidemia and endothelial dysfunction.

It rise the possibility that the polyphenols contained in Red Grape Cells (RGC) by activation SIRT1 may also exert beneficial effects in subjects affected by type 2 diabetes

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Type 2 diabetes patients
  • HbA1C > 7 %
  • Duration of diabetes: 0.5 to 20 years
  • Subjects ≥ 30 and ≤70 years of age
  • BMI: 22 to 35 kg/m2
  • Fasting Triglyceride serum level ≥ 150 mg/dl
  • All oral antidiabetic treatments will be allowed, with the exception of thiazolidinediones (glitazones).i.e. pioglitazone (Actos) or rosiglitazone (Avandia). Insulin and no GLP-1 analogs will not be allowed.
  • Normal liver and kidney function
  • Normal thyroid function
  • Acceptable health beside diabetes based on interview, medical history, physical examination, and laboratory tests
  • Willingness to avoid the use of over-the-counter medications, herbs, or supplements throughout the entire study.
  • Willingness to avoid ingestion of any foods containing peanuts, bilberries, blueberries, cranberries, strawberries, raspberries, grapes, grape juice, cocoa powder, dark chocolate, and red wine throughout the entire study
  • Stable physical activity pattern during the three months immediately preceding study
  • Usually wakes up between 06:00 and 07:00 and goes to sleep between 22:00 and 24:00.
  • No shift work within 5 years of the study
  • Did not cross time zones within 1 month of the study
  • Read and understood the informed consent form and signed it voluntarily

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Exclusion criteria

  • Type 1 diabetes
  • Clinically significant pulmonary, cardiac, renal, hepatic, neurologic, psychiatric, infectious, malignant disease
  • Abnormal liver function tests defined as an increase by a factor of at least 2 above the upper normal limit of alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST)
  • Pregnancy or lactation
  • Illicit drug abuse or alcoholism
  • Treatment with thiazolidinediones (glitazones).i.e. pioglitazone (Actos) or rosiglitazone (Avandia).
  • Insulin and or GLP-1 analogs will not be allowed.
  • Anti hyperlipidemic treatment with fibrates. Statins will be allowed
  • Subjects taking anoretic drugs during the month immediately prior to study
  • Subjects on steroid treatment
  • Those with major illnesses, liver, heart, kidney, lung, infectious, neurological, psychiatric, immunological or neoplastic diseases,
  • Those with eating disorders
  • Known hypersensitivity to grapes, soy and/or casein
  • Subjects after bariatric surgery, will be excluded

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Treatment and study plan

Red Grape Cells (RGC)

Dietary Supplement

Red Grape Cells (RGC) 1000 mg powder once daily by mouth for three month

Other names: RGC

Placebo (for Red Grape Cells (RGC))

Dietary Supplement

Placebo (for Red Grape Cells (RGC)) powder manufactured to mimic Red Grape Cells (RGC) 1000 mg powder

Other names: RGC Placebo

Primary outcomes

  1. Fasting and postprandial Clock Genes expression in peripheral blood cells (PBC)

    Time frame: Fasting and every hour after meal challenge in two occasions : at baseline (day 1) and after 12 weeks of of supplementation with RGC or Placebo .

    In all 40 subjects the effects of 12 weeks supplementation with RGC or placebo will be assessed .The clock gene expression will be measured in peripheral blood cells (PBC), at baseline (Day 1) and again after 12 weeks of supplementation The blood samples will be taken for Clock Genes expression at fasting and after meal challenge every hour until 4 hours

Secondary outcomes

  1. Fasting HbA1c

    Time frame: Fasting blood levels will be taken at baseline and after 12 weeks of supplementation with RGC or placebo

    In all 40 subjects, fasting blood levels for HbA1c, will be measured at baseline and after 12 weeks of supplementation treatment with RGC n=20 or placebo n=20

Other outcomes

  1. fasting and postprandial glucose, Insulin, GLP-1, asymmetric dimethylarginine (ADMA),and lipid plasma levels

    Time frame: The samples will be taken at fasting and every hours until 4 hours after meal challenge, in to occasions at baseline and after 12 week of supplementation with RGC or Placebo

    In all 40 subjects the effects of RGC ingestion or placebo will be evaluated in at baseline and after 12 weeks of supplementation with RGC or placebo. The blood samples will be taken at fasting and every hour up to 4 hours after meal challenge for quantification of Glucose, Insulin, glucagon-like peptide-1 (GLP-1), ADMA and for lipid plasma levels.

Sponsors and collaborators

Lead sponsor

Tel Aviv University

Other

Collaborators

  • Wolfson Medical Center

Registry information

Official study title

Effects of Red Grape Cells (RGC) Powder on Glycemic and Lipid Control in Patients With Type 2 Diabetes ¬ A Double-blind, Randomized, Placebo Controlled Study

Acronym: RGC-T2D

Important dates

Study start
2013
Primary completion
2014
Study completion
2017
First posted
Sep 10, 2013
Registry last updated
Aug 28, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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