How the European eel (Anguilla anguilla) loses its skeletal framework across lifetime

TY - JOUR

T1 - How the European eel (Anguilla anguilla) loses its skeletal framework across lifetime

AU - Rolvien, Tim

AU - Nagel, Florian

AU - Milovanovic, Petar

AU - Wuertz, Sven

AU - Marshall, Robert Percy

AU - Jeschke, Anke

AU - Schmidt, Felix N

AU - Hahn, Michael

AU - Witten, P Eckhard

AU - Amling, Michael

AU - Busse, Björn

N1 - © 2016 The Author(s).

PY - 2016/10/26

Y1 - 2016/10/26

N2 - European eels (Anguilla anguilla) undertake an impressive 5 000 km long migration from European fresh waters through the North Atlantic Ocean to the Sargasso Sea. Along with sexual maturation, the eel skeleton undergoes a remarkable morphological transformation during migration, where a hitherto completely obscure bone loss phenomenon occurs. To unravel mechanisms of the maturation-related decay of the skeleton, we performed a multiscale assessment of eels' bones at different life-cycle stages. Accordingly, the skeleton reflects extensive bone loss that is mediated via multinucleated bone-resorbing osteoclasts, while other resorption mechanisms such as osteocytic osteolysis or matrix demineralization were not observed. Preserving mechanical stability and releasing minerals for energy metabolism are two mutually exclusive functions of the skeleton that are orchestrated in eels through the presence of two spatially segregated hard tissues: cellular bone and acellular notochord. The cellular bone serves as a source of mineral release following osteoclastic resorption, whereas the mineralized notochord sheath, which is inaccessible for resorption processes due to an unmineralized cover layer, ensures sufficient mechanical stability as a part of the notochord sheath. Clearly, an eel's skeleton is structurally optimized to meet the metabolic challenge of fasting and simultaneous sexual development during an exhausting journey to spawning areas, while the function of the vertebral column is maintained to achieve this goal.

AB - European eels (Anguilla anguilla) undertake an impressive 5 000 km long migration from European fresh waters through the North Atlantic Ocean to the Sargasso Sea. Along with sexual maturation, the eel skeleton undergoes a remarkable morphological transformation during migration, where a hitherto completely obscure bone loss phenomenon occurs. To unravel mechanisms of the maturation-related decay of the skeleton, we performed a multiscale assessment of eels' bones at different life-cycle stages. Accordingly, the skeleton reflects extensive bone loss that is mediated via multinucleated bone-resorbing osteoclasts, while other resorption mechanisms such as osteocytic osteolysis or matrix demineralization were not observed. Preserving mechanical stability and releasing minerals for energy metabolism are two mutually exclusive functions of the skeleton that are orchestrated in eels through the presence of two spatially segregated hard tissues: cellular bone and acellular notochord. The cellular bone serves as a source of mineral release following osteoclastic resorption, whereas the mineralized notochord sheath, which is inaccessible for resorption processes due to an unmineralized cover layer, ensures sufficient mechanical stability as a part of the notochord sheath. Clearly, an eel's skeleton is structurally optimized to meet the metabolic challenge of fasting and simultaneous sexual development during an exhausting journey to spawning areas, while the function of the vertebral column is maintained to achieve this goal.

U2 - 10.1098/rspb.2016.1550

DO - 10.1098/rspb.2016.1550

M3 - SCORING: Journal article

C2 - 27798301

VL - 283

SP - pii: 20161550

JO - P ROY SOC B-BIOL SCI

JF - P ROY SOC B-BIOL SCI

SN - 0962-8452

IS - 1841

ER -