Study of Arginine Metabolism and Nitric Oxide Formation in Relation to Glutamine Supply in Severely Burned Patients

Mass General Brigham

Status: Unknown

Conditions: Burns

Treatments: Dietary Supplement: Alteration in nutritional support

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00216970

5P50GM021700-28 (U.S. NIH Grant/Contract)

1999-P-008460

Details and patient eligibility

About

The purpose of the study is to understand the way the body uses amino acids and proteins in burned patient during the time they cannot eat normally. This study aims to understand the metabolism of the amino acid arginine in the body after burn injury. The results of this study will help determine the best composition of food needed during an acute burn injury so that body can more efficiently use the supplied nutrient for optimal burn wound healing and early recovery.

Full description

The principle sources of plasma free arginine are (i) diet, (ii) release from protein breakdown and (iii) de novo synthesis directly from citrulline and the recycling of orthinine via the urea cycle. The major pathway of arginine disposal is i)oxidation via orthinine glutamate and subsequently the Tricarboxylic Acid (TCA) cycle and ii)via formation of nitric oxide. The latter pathway plays an important regulatory role in the body's response to stress and is significantly increased after burn injury.

Previous studies with burn patients show i)an increased rate of total arginine flux, ii)a limited rate of arginine de novo synthesis, and iii) an apparent increase in the rate of arginine catabolism as measured indirectly by increased orinthine oxidation. These changes render arginine a conditionally essential amino acid for burn patients. Studies have shown that feeding glutamine to healthy adults significantly alters the blood concentrations of urea cycle intermediates arginine, citrulline and orthinine. Therefore, we hypothesize that the availability of arginine can be improved in the burn patient by supplementing total parenteral nutrition (TPN) support with glutamine.

Using stable isotope tracer studies our specific aims are:

1. To explore the dynamic aspects of arginine and citrulline metabolism. There will be an emphasis on arginine disposal via oxidation and urea nitrogen formation via nitric oxide production.
2. To explore the effect of a) depleting arginine and its immediate precursors proline and glutamine, and b)glutamine supplementation on the metabolic pathways of burn patients.
3. To estimate the rate of nitric oxide (NO) formation in burn patients using arginine and citrulline tracers

Enrollment: 16 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Burn patients being treated at MGH Burn Unit with one or more of the following criteria: 1) >=5% TBSA; 2) inhalation injury; or 3) resting energy expenditure (REE) of >15% of the predicted Basal Metabolic Rate using the Harris-Benedict equation.
• Must be receiving total parenteral nutrition in the course of their treatment.

Exclusion criteria

• Patients with thyroid disease
• Patients who are not hemodynamically stable or show unstable vital signs
• Patients at the stage of major organ failure, e.g. renal and/or liver failure.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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16 participants in 2 patient groups

1

No Intervention group

Description:

Patients will receive nutritional support in which the contents of arginine = 0, glutamate = 0 and proline = 0. Stable isotope tracer studies will be conducted to investigate the whole body protein metabolism and the utilization of arginine in critically ill burn patients.

Treatment:

Dietary Supplement: Alteration in nutritional support

2

No Intervention group

Description:

In arm 2 patients will receive nutritional support which will provide glutamine 0.5g/kg/day. Stable isotope tracer studies will be conducted to investigate the whole body protein metabolism and the utilization of arginine in critically ill burn patients.

Treatment:

Dietary Supplement: Alteration in nutritional support