Blood Is a Window into Health and Disease.

Abstract

Human physiology is complex, with integrated networks of tissues and organs that coordinate complex functions. Within this network of networks, the blood is a uniquely ubiquitous intersecting tissue: It interacts with all other tissues and organs, supplying oxygen and necessary nutrients. It is home to vital immune cells like lymphocytes, macrophages, and leukocytes. It plays host to a variety of small molecules, from metabolites (compounds involved in metabolic reactions) to cell-free DNA and RNA. It also contains a diverse set of proteins arising from virtually every intersecting organ—by secretion, apoptosis, or enzymatic cleavage from cell membranes—that can serve as sensors for the state of their cognate organs. Accordingly, blood is a valuable window into health and disease.\n\nThus, deconvoluting the blood proteome provides unique opportunities for understanding the physiological and pathological states of an individual in the context of these organ systems. Although several different technologies exist that enable the characterization of diverse blood proteins, capture agent-based approaches represent a promising path forward regarding specific recognition for a high number of potential targets. New advancements are addressing accurate, reliable protein identification and the characterization of cross-reactivities (if any)—both concerns for aptamer deployment for clinical use (1).\n\nIn a recent publication in Science , Emilsson et al. explored the complex proteomic network structure of the blood through the use of slow off-rate modified aptamer (SOMAmer)-based technology (2). In a cohort of 5457 individuals >65 years of age whose complete genome sequence had been determined, the authors profiled a total of 4137 blood serum proteins and constructed a coregulation network. This blood protein network consisted of 27 coregulatory modules that included 85% of the measured proteins. Several of these modules—representing functional protein groups—were enriched for tissue-specific signatures and were found to be associated with cardiovascular and metabolic disease. These functional modules …