Molecular Pathways Related to Short-term Fasting Response

February 12, 2020 updated by: IMDEA Food

Evaluation of p21 Induction and Molecular Pathways Related to Short-term Fasting Response

This study will evaluate the effect of short-term fasting (36 hours) in gene expression in blood cells in healthy volunteers.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Fasting is a nutritional intervention consisting on the restriction of nutrient intake during a relatively long period of time. It elicits a profound metabolic reprogramming aimed at shifting nutrient supply from external food intake to internal stored nutrients. Periodic activation of this complex response, termed periodic or intermittent fasting (IF), elicits numerous protective effects against aging, metabolic alterations, neurological disorders and cardiovascular health. Short-term fasting is protective in different stress scenarios, including ischemia reperfusion, bouts of inflammation and chemotherapy-induced toxicity, and improves the anti-tumor efficacy of chemotherapy. Although the basic physiology of fasting is well known, the molecular mechanisms underlying its beneficial effects are not yet completely understood.

In mammals, the response to short-term fasting (from 12 to 48 hours) in terms of nutrient mobilization through the bloodstream has been extensively studied. Fasting follows sequential phases, during which nutrients are released from different storing depots. First, glucose is released from glycogen stores in the liver and muscle. Upon depletion of glycogen, two fasting mechanisms are activated: fatty acids are exported from the adipose tissue into the bloodstream in the form of free fatty acids (FFAs), reaching the liver where they are used to produce ketone bodies, a process termed ketogenesis. Also, gluconeogenesis is activated in the liver, generating glucose mainly from glycerol (released during lipolysis) and amino acids, that originate mainly from muscle breakdown. All these physiological responses are tightly regulated by hormonal and molecular mechanisms.

At the hormonal level, fasting induces a decrease in blood insulin, leptin and ghrelin, and an increase in glucagon levels, while blood adiponectin remains unchanged. Also, several signal transduction pathways are affected by fasting. PPARalpha, a nuclear receptor of fatty acids, becomes activated by the fasting-mediated increase in blood Free fatty Acids (FFAs) and triggers the expression of many target genes in several tissues, including blood cells. It has been shown that the Cyclin Dependent Kinase (CDK) inhibitor p21 is highly upregulated during short-term fasting in many mouse tissues. Moreover, it is known that p21-null mice are unable to endure normal periods of fasting and that p21 is required for the full activation of PPARa target genes both in vivo and in isolated hepatocytes.

In the current study, the investigators wanted to study for the first time molecular mechanisms of fasting that still remained unexplored, specially the expression induction of p21 and PPARalpha signalling pathway. For this, the investigators analyzed blood samples from healthy volunteers subjected to 36 hours of fasting, to explore gene expression in Peripheral Blood Mononuclear Cells (PBMCs).

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Spain
      • Madrid, Spain, 28049
        • IMDEA Food

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Men and women between 18 - 50 years old.
  • BMI >20<30
  • Adequate education level and comprehension of the clinical study
  • Willingness to participate in the study as a volunteer and to provide written consent

Exclusion Criteria:

  • BMI <20 (thinness)
  • BMI >30 (obesity)
  • Abnormal low glucose levels after fasting
  • Having donated blood less than 8 weeks before starting the study
  • Subjects who report special discomfort after previous periods of short fasting
  • Diagnosis of type 2 Diabetes mellitus (insulin-dependent)
  • Dyslipidemia under pharmacological treatment
  • High blood pressure under pharmacological treatment
  • Dementia, neurological disease or reduction of cognitive function
  • Severe illness (hepatic disease, renal disease, etc
  • Taking medications that could affect the lipid and glycemic profiles (statins, fibrate, diuretics, corticoids, anti-inflammatory, hypoglycemic or insulin) 30 days before the beginning of the study.
  • Taking medications or substances for weight loss management (15 days before the beginning of the study)
  • Pregnancy or lactation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Fasting
The participants will follow a short-term fasting period for 36 hours
Other: Fasting
Food intake restriction

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in gene expression in PBMCs after fasting
Time Frame: Baseline, 24 hours and 48 hours later
Expression analysis of p21, Pyruvate Dehydrogenase Kinase 4 (PDK4), Carnitine palmitoyltransferase 1 (CPT1), Adipophilin (ADFP) and Solute carrier family 25, member 50 (SLC25A50) were performed in a HT-7900 Fast Real time polymerase chain reaction (PCR). Quantifications were made applying the ΔCt method (ΔCt = [Ct of gene of interest - Ct of housekeeping]). The housekeeping genes used for input normalization were β-actin (ACTB) and ribosomal protein lateral stalk subunit P0 (RPLP0).
Baseline, 24 hours and 48 hours later

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in Insulin levels in response to fasting
Time Frame: Baseline, 24 hours and 48 hours later
Insulin levels (International Units per milliliter) were measured with a kit from Abbott Laboratories, by luminescent immunoassay using the Architect instrument from Abbott Laboratories.
Baseline, 24 hours and 48 hours later
Changes in Free Fatty Acids levels in response to fasting
Time Frame: Baseline, 24 hours and 48 hours later
Free fatty acids levels (moles per milliliter) were evaluated with a kit from Abbott Laboratories, by enzymatic spectrophotometric assays using an Architect instrument from Abbott Laboratories.
Baseline, 24 hours and 48 hours later
Changes ketone bodies in response to fasting
Time Frame: Baseline, 24 hours and 48 hours later
Ketone bodies concentration (moles per milliliter) will be measured with a kit from Sigma-Aldrich, by an enzymatic spectrophotometric assay using an microplate reader from Thermo Fisher.
Baseline, 24 hours and 48 hours later
Changes in leptin levels in response to fasting
Time Frame: Baseline, 24 hours and 48 hours later
Leptin levels (nanograms per milliliter) were measured with a kit from Mercodia by a non-competitive automatic ELISA immunoanalysis
Baseline, 24 hours and 48 hours later
Changes in lipid profile in response to fasting
Time Frame: Baseline, 24 hours and 48 hours later
To evaluate lipid improvements the following measurements were considered: Triacylglycerol, Total Cholesterol, low Density Lipoprotein and High-Density Lipoprotein measured by routine laboratory (CQS, Madrid, Spain) methods.
Baseline, 24 hours and 48 hours later
Subjective evaluation of tolerance to fasting
Time Frame: 36 hours of fasting
To evaluate the tolerance to fasting, participants will fill in a fasting tolerance test based on the symptoms they feel, this will result in a final score of tolerance to fasting.
36 hours of fasting

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

IMDEA Food

Collaborators

Centro Nacional de Investigaciones Oncologicas CARLOS III

Investigators

  • Principal Investigator: Pablo J Fernandez-Marcos, PhD, IMDEA Food
  • Principal Investigator: Manuel Serrano Marugán, PhD, Spanish National Cancer Research Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 7, 2016

Primary Completion (Actual)

May 18, 2016

Study Completion (Actual)

June 15, 2016

Study Registration Dates

First Submitted

February 5, 2020

First Submitted That Met QC Criteria

February 5, 2020

First Posted (Actual)

February 7, 2020

Study Record Updates

Last Update Posted (Actual)

February 17, 2020

Last Update Submitted That Met QC Criteria

February 12, 2020

Last Verified

January 1, 2020

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • IMD PI0025

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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