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L-Citrulline Supplementation Pilot Study for Overweight Late Onset Asthmatics (SANDIA)

This study has been completed.
Information provided by (Responsible Party):
Fernando Holguin, University of Pittsburgh Identifier:
First received: October 16, 2012
Last updated: June 29, 2017
Last verified: June 2017
In people who develop asthma after the age of 12 and who are also overweigh, there can be an increased burden of asthma symptoms, more flare-ups, and poorly-controlled asthma when compared to normal weight asthmatics. Certain factors are more abundant in the blood of individuals who are obese. One such factor is derived from the metabolism of an amino acid found in your diet, which is known as L-arginine (Amino acids are most commonly known as the building blocks of proteins, the same as the proteins found in food). This factor is called asymmetric dimethylarginine or ADMA. The balance of L-arginine to ADMA may be important to the health of subjects with asthma. The balance between L-arginine and ADMA plays an important role in producing nitric oxide (NO) in the airways. NO is normally produced in the lung and plays a major role in maintaining airways open and functioning normally. Our research has shown that in subjects with asthma who are overweight and developed asthma later in life, the combination of low L-arginine and high ADMA, may lead to lower NO levels. We are asking participants in this study to take L-citrulline, which is converted to L-arginine by your body, as a supplement for a period of one week. We anticipate that L-citrulline will restore NO levels in the airways, by increasing the ratio of L-arginine to ADMA

Condition Intervention Phase
Asthma Dietary Supplement: L-citrulline Phase 1

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: L-Citrulline Supplementation Pilot Study for Overweight Late Onset Asthmatics

Further study details as provided by Fernando Holguin, University of Pittsburgh:

Primary Outcome Measures:
  • Exhaled nitric oxide [ Time Frame: 1 week ]
    Patients will be randomized to 1 week of 3 g of L-citrulline/day vs matching placebo, The outcome is the pre to post intervention change in exhaled NO

Secondary Outcome Measures:
  • Sputum and plasma L-arginine/ADMA levels [ Time Frame: 1 week ]
    This outcome compares the pre to post L-citrulline supplementation changes in sputum and plasma L-arginine/ADMA

Enrollment: 10
Actual Study Start Date: September 7, 2013
Study Completion Date: June 1, 2017
Primary Completion Date: June 1, 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: L-citrulline
3-gr/day of L-citrulline effervescent powder mix
Dietary Supplement: L-citrulline
Patients will take 3-gr of L-citrulline/day for 7 days
Other Name: L-citrulline 3 gr efervescent powder
Placebo Comparator: Placebo
3 gr of Placebo/day matching L-citrulline effervescent powder
Dietary Supplement: L-citrulline
Patients will take 3-gr of L-citrulline/day for 7 days
Other Name: L-citrulline 3 gr efervescent powder


Ages Eligible for Study:   18 Years to 75 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Male and female patients, 18-75 yrs old, from all racial/ethnic backgrounds
  • Diagnosis of asthma for >1 yr
  • BMI ≥ 30
  • Baseline pre-bronchodilator FEV1 between 60 and 90% predicted with a 12% or greater bronchodilator response to 4 puffs of albuterol
  • Smoking history <20 pack years and no smoking in the last year
  • Able to identify age of asthma onset

Exclusion Criteria:

  • Respiratory tract infection within the last 4 weeks;
  • Oral CS burst within the last 4 weeks or regular systemic CS use
  • Hospitalization within the last 3 months
  • ER visit within the 4 weeks
  • Significant or uncontrolled concomitant medical illness including (but not limited to) heart disease, cancer, diabetes
  • Current smoking or within the previous 12 months
  • Current use of statins for the past 30 days (Statins lower ADMA levels)
  • Pregnancy
  • Intolerance or allergy to L-arginine or L-citrulline
  • Phosphodiesterase inhibitors
  • Taking oral nitrates
  Contacts and Locations
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, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01715844

United States, Pennsylvania
Asthma Institute, University of Pittsburgh
Pittsburgh, Pennsylvania, United States, 15213
Sponsors and Collaborators
University of Pittsburgh
Principal Investigator: Fernando Holguin, MD MPH University of Pittsburgh
  More Information

Responsible Party: Fernando Holguin, Assistant Professor of Medicine, University of Pittsburgh Identifier: NCT01715844     History of Changes
Other Study ID Numbers: L-citrulline Asthma
Study First Received: October 16, 2012
Last Updated: June 29, 2017

Keywords provided by Fernando Holguin, University of Pittsburgh:

Additional relevant MeSH terms:
Body Weight
Signs and Symptoms processed this record on August 18, 2017