Phenylalanine-free Diet Lowers the Blood Phenylalanine Levels in Patients With High Phenylalanine Level in the Intensive Care Unit

Background:

Patients in the intensive care unit often suffer from problems such as high metabolic rate and high tissue breakdown rate under the severe stress of critical diseases. Phenylalanine is an amino acid in the human body and is rich in muscle tissue. However, current studies have found that if the concentration of phenylalanine in the blood is abnormally increased, it may indicate that the tissue is decomposing in large quantities. This phenomenon may be related to disease severity. Our recent observational study of patients in the intensive care unit (ICU) found that patients with elevated blood phenylalanine had a four-fold increase in mortality within one year.

The most common cause of phenylalanine concentration elevation in the blood is a rare disease that occurs in infants with congenital metabolic abnormalities, called congenital phenylketonuria (PKU). The abnormally elevated phenylalanine concentration can lead to toxicity and cause brain hypoplasia, mental retardation, consciousness disturbance, and even seizure. These PKU patients must be treated with milk diet that contains low amount of phenylalanine in order to lower the phenylalanine concentrations. At present, in medicine, although there have been clear medical care strategy for infants with congenital PKU, there is still no clear medical care strategy for adult patients.

Research purpose: To investigate whether patients with high blood phenylalanine concentration in the intensive care unit can reduce the blood phenylalanine concentration by a diet without phenylalanine, so as to develop personalized high-quality and specific treatments.

Methods: