Casein Protein and Leucine Supplementation in Chronic Obstructive Pulmonary Disease (COPD)
Casein Protein and Leucine Supplementation in Chronic Obstructive Pulmonary Disease (COPD)
Weight loss commonly occurs in patients with COPD, negatively influencing their quality of
 life, treatment response and survival. Loss of muscle protein is generally a central
 component of this weight loss and independently increases mortality. This study will provide
 relevant clinical information in regards to the anabolic properties of specific dietary
 substrates and their co-active anabolic effects. Hypotheses: 1) That supplementation of a
 hydrolyzed casein-based protein meal with the addition of carbohydrates is more anabolic than
 a hydrolyzed casein-based protein meal without carbohydrates in COPD patients and healthy
 older adults; 2) That leucine addition to a hydrolyzed casein-based protein meal only
 enhances the protein anabolic response in COPD patients and healthy older adults when
 carbohydrates are not added to the protein meal; 3) That COPD patients have a more efficient
 protein anabolic response to a hydrolyzed casein-based protein meal than healthy older
 adults.

 A fifth study day was added to measure protein requirements of included individuals to be
 able to interpret their response to the other interventions on the other study days, and to
 test the hypothesis that subjects with lower protein requirements respond less to
 intervention with leucine and/or carbohydrates. For the 5th additional test day we will first
 approach the 10 COPD and 10 healthy subjects who already completed the first 4 study days
 (and signed the re-contact form) to come back for this extra test day. We will (pre-)screen
 these subjects by phone for eligibility and check for changes in their recent medical history
 (with help of the (pre-)screening questionnaires in CRF). If all inclusion criteria are still
 met, these subjects will be asked to provide a written re-consent. If necessary, we will
 recruit new subjects who will complete only one of the four test days (i.e. the test day on
 which the hydrolyzed casein-based protein meal with carbohydrates is provided) and the
 additional 5th study day.
The study involves 5 study days. The duration of the first 4 study days is approximately 6.5
 hours per day and the duration of the 5th study day is approximately 8 hours. On each of the
 first 4 study days the effect a casein protein meal with or without leucine and carbohydrates
 will be examined. On the fifth study day the effect of 4 different levels of casein protein
 and carbohydrate intake by sip feeding (every 20 minutes) is examined.

 Also, subjects will receive a mixture of amino acids (little parts of protein) which are a
 little bit heavier than normal, called stable isotopes. This is the so-called stable isotope
 method to investigate protein behavior in the body (protein kinetics). Altogether about 75 ml
 of blood will be drawn per study day to assess outcome measures.
Inclusion criteria COPD subjects:

 -  Ability to walk, sit down and stand up independently

 -  Age 45 years or older

 -  Ability to lie in supine or elevated position for 5.5 hours

 -  Diagnosis of moderate to very severe chronic airflow limitation and compliant to the
 following criteria: Forced Expiratory Volume(FEV1)/Forced Vital Capacity (FVC) < 0.70
 and FEV1 < 70% of reference FEV1

 -  Clinically stable condition and not suffering from a respiratory tract infection or
 exacerbation of their disease (defined as a combination of increased cough, sputum
 purulence, shortness of breath, systemic symptoms such as fever, and a decrease in
 FEV1 > 10% compared with values when clinically stable in the preceding year) at least
 4 weeks prior to the first test day

 -  Shortness of breath on exertion

 -  Willingness and ability to comply with the protocol, including:

 -  Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study
 visit

 Inclusion criteria healthy control subjects:

 -  Healthy male or female according to the investigator's or appointed staff's judgment

 -  Ability to walk, sit down and stand up independently

 -  Age 45 years or older

 -  Ability to lay in supine or elevated position for 5.5 hours

 -  No diagnosis of chronic airflow limitation and compliant to the following criteria:
 FEV1/FVC > 0.70 and FEV1 ≥ 80% of reference FEV1

 -  Willingness and ability to comply with the protocol, including:

 -  Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study
 visit

 Exclusion Criteria all subjects:

 -  Any condition that may interfere with the definition 'healthy subject' according to
 the investigator's judgment (for healthy control group only)

 -  Established diagnosis of malignancy

 -  Established diagnosis of Insulin Dependent Diabetes Mellitus

 -  History of untreated metabolic diseases including hepatic or renal disorder

 -  Presence of acute illness or metabolically unstable chronic illness

 -  Recent myocardial infarction (less than 1 year)

 -  Any other condition according to the PI or nurse that was found during the screening
 visit, that would interfere with the study or safety of the patient

 -  BMI of < 18.5 or ≥ 35 kg/m2

 -  Dietary or lifestyle characteristics:

 -  Use of protein or amino acid containing nutritional supplements within 5 days of
 first test day

 -  Current alcohol or drug abuse

 -  Indications related to interaction with study products:

 -  Known allergy to milk or milk products

 -  Use of long-term oral corticosteroids or short course of oral corticosteroids 4 weeks
 preceding first test day

 -  Failure to give informed consent or Investigator's uncertainty about the willingness
 or ability of the subject to comply with the protocol requirements

 -  (Possible) pregnancy