Figure .4 shows several biomarkers related to age in urine (MTBLS404) visualized through the DSMN approach. Red dashed lines show biomarkers only one or two steps removed from one another; blue dotted lines show reactions between biomarkers three steps away. The biomarkers fill color is linked to the log2 values with a blue-white-red gradient depicting negative to positive values. Fifteen compounds out of 30 queried biomarkers could be linked to one another through directed shortest path calculations, one metabolite (pantothenic acid, also measured in the previously described study MTBLS265) was found to be part of the graph database, however not connectable in a directed manner. The remaining biomarkers were not part of the graph database. Figure .5 visualizes aging biomarkers found in blood or urine for two biological sexes (Rist et al.) , with diamonds to depict the matrix blood and V-shapes (upside down triangles) urine. Yellow-green dash/dotted lines show Urea (Cycle) pathways; blue dotted lines the Cerebral Organic Acidurias pathway; lipid pathways (including Fatty Acid Beta Oxidation) are depicted with pink contiguous arrows. Eleven compounds out of the 19 queried identifiers could be linked through directed shortest path calculations (including D-and L-ornithine as individual compounds). These included seven (out of thirteen) compounds measured in plasma, and four (out of six) in urine. Eight identifiers could not be found in the whole graph, or are labeled as side metabolites, e.g. potassium. The aging biomarkers were scattered over several pathways, with the urea (cycle) surprisingly not connecting the urinary biomarkers together. Furthermore, two urinary markers (glutaric acid and N-Acetyl-L-aspartic acid) are directly linked to the cerebral organic acidurias pathway, which describes the accumulation of organic acids in body fluids; an excess of these acids leads to severe movement symptoms. Last, the biomarker choline (measured in blood samples) is connected to several lipid pathways, at some distance from the other biomarkers.