Try the modernized beta website. Learn more about the modernization effort.
Working… Menu

Time Course for Fasting-induced Autophagy in Humans

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT04842864
Recruitment Status : Recruiting
First Posted : April 13, 2021
Last Update Posted : February 2, 2022
Glenn Foundation for Medical Research
Information provided by (Responsible Party):
Montefiore Medical Center

Brief Summary:
Autophagy, which involves the degradation of aged or damaged cellular components, has been shown to extend healthspan and lifespan in multiple organisms, including flies, worms, and mice. Research has also demonstrated that autophagy declines with age in these simpler experimental models. However, human studies are lacking. Our study seeks to determine whether fasting, a robust stimulus of autophagy, upregulates autophagy in humans, and whether autophagy is reduced in healthy older people compared to healthy younger individuals.

Condition or disease Intervention/treatment Phase
Fasting Autophagy Aging Well Ketosis, Metabolic Behavioral: Fasting Not Applicable

Detailed Description:

Autophagy is a cellular quality control pathway that degrades aged or damaged organelles and protein aggregates within lysosomes. By doing so, autophagy provides an alternate source of energy for cells to cope with adverse conditions. The level of autophagy determines the degree to which aged cells are able to eliminate damaged organelles and/or toxic aggregates and mount a protective response against stress. At the physiological level, nutrient deprivation or fasting is one of the most robust stimuli for autophagy across diverse experimental systems.1 Our lab has shown important roles for autophagy in lipid/glucose homeostasis and regulation of energy balance. We have found that autophagy degrades cellular lipid stores via a process we described as lipophagy. We have also shown contributions of autophagy to the regulation of feeding as well as its developmental roles in maintenance of muscle and fat mass. In addition to these physiological functions, a number of studies have revealed that mice lacking autophagy in the central nervous system show rapid onset of neurodegeneration and an early death.2,3 These studies support a central role of autophagy in the maintenance of healthspan.

It is well-established that autophagy activity declines with age, which has led to the hypothesis that autophagy failure contributes to the metabolic syndrome of aging. In fact, young mice with tissue-specific knockout of the autophagy gene Atg7 display features of aging, including loss of muscle mass (mimicking sarcopenia of aging), fatty liver, decreased adipose lipolysis, de-differentiation of brown fat, and pancreatic β-cell dysfunction.4-6 Conversely, restoration of autophagy via pharmacological or genetic approaches prevents age-associated decline in cell function and improves stress response-thus directly extending healthspan. As a consequence, there is great interest in developing new experimental approaches to prevent age-associated chronic diseases. In fact, caloric restriction (CR) has been shown to stimulate autophagy and extend lifespan and healthspan in multiple experimental models. While these CR studies were carried out in simpler organisms, such as flies, worms, and mice,7-9 similar studies in humans are largely lacking. Since autophagy is activated by starvation, the prevailing hypothesis is that caloric restriction (CR) or more physiological approaches such as intermittent fasting will stimulate autophagy in humans, which in turn will prevent or retard the onset of age-associated chronic diseases. There is limited knowledge if indeed extended periods of fasting will activate autophagy in humans. In addition, we do not know what duration of fasting may be required to stimulate autophagy in humans. Finally, we do not know if, nor by how much, fasting-induced autophagy is reduced in aging humans. Due to the aforementioned gaps in our knowledge regarding autophagy in humans, in this study we will test the ability of extended periods of restriction to food to stimulate autophagy in healthy, young individuals. Further, we will compare the extent to which autophagy is reduced in healthy older subjects, when compared to those observed in young controls. In our study, we will be using samples of adipose tissue, a metabolically active endocrine organ, and peripheral blood cells, which have both been evaluated in prior autophagy studies and can be obtained in a less invasive manner.

Layout table for study information
Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 20 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Time Course for Fasting-induced Autophagy in Humans
Actual Study Start Date : November 19, 2021
Estimated Primary Completion Date : May 31, 2022
Estimated Study Completion Date : February 1, 2023

Arm Intervention/treatment
Experimental: Young
10 healthy men and women 18-35 yo.
Behavioral: Fasting
23 hours fasting

Active Comparator: Older adults
10 healthy men and women 65-85 yo
Behavioral: Fasting
23 hours fasting

Primary Outcome Measures :
  1. Autophagy flux [ Time Frame: 23 hours ]
    The turnover rate of the autophagosome marker LC3-II will be assessed. LC3-II flux will be performed in freshly isolated fat tissues and in PBMCs at various timepoints. Freshly collected fat tissue explants and PBMCs will be incubated in dishes with high-glucose culture medium (DMEM) in the presence or absence of lysosomal inhibitors (Lys Inh), leupeptin (200uM) and ammonium chloride (20uM) at 37°C, 5% CO2 for 4 hours. Fat explants and scraped PMBC pellets will then be homogenized in a buffer containing protease and phosphatase inhibitors and subjected to immunoblotting for LC3. Autophagy flux will be determined by subtracting the densitometric value of LC3-II in Lys Inh-untreated samples from the Lys Inh-treated samples.

Secondary Outcome Measures :
  1. Level of ketone bodies [ Time Frame: 23 hours ]
    Levels of ketones in the plasma will be assessed with blood draws at various timepoints.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Layout table for eligibility information
Ages Eligible for Study:   18 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy men and women 18-35 years of age
  • Healthy men and women 65-85 years of age

Exclusion Criteria:

  • Serious acute/chronic illness (e.g., active cancer, inflammatory states, RA, SLE, or a CVD event within past 6 months)
  • Diabetes or pre-diabetes with an A1c >6.0%
  • Pregnancy
  • BMI >30 kg/m2 or <20 kg/m2
  • eGFR <45 ml/min
  • ALT >3x ULN
  • Hct <35 or Hb <10
  • Exclusionary meds: calcium channel blockers, anticonvulsants or other drugs shown to affect autophagy (see table below)
  • Food allergy or known food intolerance
  • Active Smoking (>1 cigarette or cigar per week)
  • Use of recreational drugs (opioids, cocaine, marijuana, etc.) in past month
  • Use of alcohol on the day prior to and the day of study
  • Shift workers or other dysregulated sleep pattern (habitual use of sleep medications, jet lag, etc.)
  • Strenuous exercise within 3 days prior to study visit 2
  • Any condition the investigator believes would impair the ability to interpret targeted outcomes

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04842864

Layout table for location contacts
Contact: Jill Crandall, MD 718-430-3765

Layout table for location information
United States, New York
Albert Einstein College of Medicine Recruiting
Bronx, New York, United States, 10461
Contact: Janet O Brown, RN    347-658-2006   
Contact: Amanda Pechman, MD         
Sponsors and Collaborators
Montefiore Medical Center
Glenn Foundation for Medical Research
Layout table for investigator information
Principal Investigator: Jill Crandall, MD Albert Einstein College of Medicine
Principal Investigator: Nir Barzilai, MD Albert Einstein College of Medicine
Principal Investigator: Rajat Singh, MD Albert Einstein College of Medicine
Layout table for additonal information
Responsible Party: Montefiore Medical Center Identifier: NCT04842864    
Other Study ID Numbers: 2021-12857
First Posted: April 13, 2021    Key Record Dates
Last Update Posted: February 2, 2022
Last Verified: January 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Layout table for additional information
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
Layout table for MeSH terms
Acid-Base Imbalance
Metabolic Diseases