TY - JOUR TI - A structure-based extracellular matrix expansion mechanism of fibrous tissue growth AU - Kalson, Nicholas S AU - Lu, Yinhui AU - Taylor, Susan H AU - Starborg, Tobias AU - Holmes, David F AU - Kadler, Karl E A2 - Krumlauf, Robb VL - 4 PY - 2015 DA - 2015/05/20 SP - e05958 C1 - eLife 2015;4:e05958 DO - 10.7554/eLife.05958 UR - https://doi.org/10.7554/eLife.05958 AB - Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis. KW - collagen KW - tendon KW - fibril KW - crimp KW - biomechanic JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -