Physiological conditions can be reflected in human urine proteome and metabolome

Abstract

Biomarkers are the measurable changes associated with physiological or pathophysiological processes. Urine, unlike blood, lacks mechanisms for maintaining homeostasis: it is therefore an ideal source of biomarkers that can reflect systemic changes. Urinary proteome and metabolome have been studied for their diagnostic capabilities, ability to monitor disease and prognostic utility. In this review, the effects of common physiological conditions such as gender, age, diet, daily rhythms, exercise, hormone status, lifestyle and extreme environments on human urine are discussed. These effects should be considered when biomarker studies of diseases are conducted. More importantly, if physiological changes can be reflected in urine, we have reason to expect that urine will become widely used to detect small and early changes in pathological and/or pharmacological conditions.

Keywords:

• biomarker
• metabolomics
• physiological conditions
• proteomics
• urine

Financial & competing interests disclosure

Y Gao is supported by the Key Basic Research Program of China (2013FY114100) and the National Basic Research Program of China (2012CB517606 and 2013CB530805). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Biomarkers are the measurable changes associated with physiological or pathophysiological processes.

• Urine is a sensitive matrix that can reflect pathological, pharmacological and physiological changes.

• Urine is an ideal biomarker source for clinical proteomics or metabolomics studies.

• Urine omics may be significantly affected by physiological conditions, such as gender, age, daily rhythms, hormone status, diet, exercise, lifestyle and extreme environments.

• Urine has the potential to detect small and early changes in pathological and/or pharmacological conditions.

• Only by accurately distinguishing between physiological and pathological conditions can we reliably identify disease biomarkers. This is also important for monitoring patient health in personalized medicine.

• Since the urinary omics reflect several physiological conditions, the knowledge of their effects should be useful to identify potential disease biomarkers in a more efficient and proper way. More efforts should be made to study the effects of physiological conditions on urine omics.

• There are tremendous opportunities in the upcoming urine biomarker era.