Quantitative mass spectrometry of urinary biomarkers

Sickle cell nephropathy: A review of novel biomarkers and their potential roles in early detection of renal involvement

Whether the underlying mutations are homozygous, heterozygous, or co-inherited with other hemoglobinopathies, sickle cell disease is known to afflict the kidneys, leading to the clinical entity known as sickle cell nephropathy (SCN). Although common, SCN remains diagnostically elusive. Conventional studies performed in the context of renal disorders often fail to detect early stage SCN. This makes the quest for early diagnosis and treatment more challenging, and it increases the burden of chronic kidney disease-related morbidity among patients. Novel diagnostic tools have been employed to overcome this limitation. In this study, we discuss various biomarkers of SCN, including those employed in clinical practice and others recently identified in experimental settings, such as markers of vascular injury, endothelial dysfunction, tubulo-glomerular damage, and oxidative stress. These include kidney injury molecule-1, monocyte chemoattractant protein-1, N-acetyl-B-D-glucosaminidase, ceruloplasmin, orosomucoid, nephrin, and cation channels, among others. Furthermore, we explore the potential of novel biomarkers for refining diagnostic and therapeutic approaches and describe some obstacles that still need to be overcome. We highlight the importance of a collaborative approach to standardize the use of promising new biomarkers. Finally, we outline the limitations of conventional markers of renal damage as extensions of the pathogenic process occurring at the level of the organ and its functional subunits, with a discussion of the expected pattern of clinical and biochemical progression among patients with SCN.

Approaches to the discovery of non-invasive urinary biomarkers of prostate cancer

Prostate cancer (PCa) continues to be one of the most common cancers in men worldwide. Prostate specific antigen (PSA) measured in blood has been used for decades as an aid for physicians to detect the presence of prostate cancer. However, the PSA test has limited sensitivity and specificity, leading to unnecessary biopsies, overdiagnosis and overtreatment of patients. For these reasons, there is an urgent need for more accurate PCa biomarkers that can detect PCa with high sensitivity and specificity. Urine is a unique source of potential protein biomarkers that can be measured in a non-invasive way. This review comprehensively summarizes state of the art approaches used in the discovery and validation of urinary biomarkers for PCa. Numerous strategies are currently being used in the discovery of urinary biomarkers for prostate cancer including gel-based separation techniques, mass spectrometry, activity-based proteomic assays and software approaches. Antibody-based approaches remain preferred method for validation of candidate biomarkers with rapidly advancing multiplex immunoassays and MS-based targeted approaches. In the last decade, there has been a dramatic acceleration in the development of new techniques and approaches in the discovery of protein biomarkers for prostate cancer including computational, statistical and data mining methods. Many urinary-based protein biomarkers have been identified and have shown significant promise in initial studies. Examples of these potential biomarkers and the methods utilized in their discovery are also discussed in this review.

Effect of Sweetened Dried Cranberry Consumption on Urinary Proteome and Fecal Microbiome in Healthy Human Subjects

The relationship among diet, human health, and disease is an area of growing interest in biomarker research. Previous studies suggest that the consumption of cranberries (Vaccinium macrocarpon) could beneficially influence urinary and digestive health. The present study sought to determine if daily consumption of sweetened dried cranberries (SDC) changes the urinary proteome and fecal microbiome, as determined in a prospective sample of 10 healthy individuals. Baseline urine and fecal samples were collected from the subjects in the fasted (8-12 h) state. The subjects then consumed one serving (42 g) of SDC daily with lunch for 2 weeks. Urine and fecal samples were collected again the day after 2 weeks of SDC consumption. Orbitrap Q-Exactive mass spectrometry of urinary proteins showed that consumption of SDC resulted in changes to 22 urinary proteins. Multiplex sequencing of 16S ribosomal RNA genes in fecal samples indicated changes in relative abundance of several bacterial taxonomic units after consumption of SDC. There was a shift in the Firmicutes:Bacteroidetes ratio, increases in commensal bacteria, and decreases or the absence of bacteria associated with negative health effects. A decrease in uromodulin in all subjects and an increase in Akkermansia bacteria in most subjects were observed and warrant further investigation. Future larger clinical studies with multiomics and multitissue sampling designs are required to determine the effects of SDC consumption on nutrition and health.