Systems Biology in Kidney Transplantation: The Application of Multi-Omics to a Complex Model

In spite of reduction of rejection rates and improvement in short-term survival post-kidney transplantation, modest progress has occurred in long-term graft attrition over the years. Timely identification of molecular events that precede clinical and histopathological changes might help in early intervention and thereby increase the graft half-life. Evolution of "omics" tools has enabled systemic investigation of the influence of the whole genome, epigenome, transcriptome, proteome and microbiome on transplant function and survival. In this omics era, systemic approaches, in-depth clinical phenotyping and use of strict validation methods are the key for further understanding the complex mechanisms associated with graft function. Systems biology is an interdisciplinary holistic approach that focuses on complex and dynamic interactions within biological systems. The complexity of the human kidney transplant is unlikely to be captured by a reductionist approach. It appears essential to integrate multi-omics data that can elucidate the multidimensional and multilayered regulation of the underlying heterogeneous and complex kidney transplant model. Herein, we discuss studies that focus on genetic biomarkers, emerging technologies and systems biology approaches, which should increase the ability to discover biomarkers, understand mechanisms and stratify patients and responses post-kidney transplantation.