part of kidney development mesenchyme development kidney mesenchyme development mah 2010-01-25T04:39:04Z biological_process GO:0072074 The biological process whose specific outcome is the progression of a kidney mesenchyme from an initial condition to its mature state. This process begins with the formation of kidney mesenchyme and ends with the mature structure. Kidney mesenchyme is the tissue made up of loosely connected mesenchymal cells in the kidney.