Is There A Blood-Bone Barrier?

Abstract

The nature of the extravascular extracellular space in bone may play an important role in the control of mass transport in bone. Do the cells lining bone surfaces control the fluid environment adjacent to bone surfaces so that its composition is different to perivascular fluid? This question has been discussed for some years, but experimental evidence has not been conclusive. Neuman published a series of papers concerned with blood-bone disequilibrium or blood-bone equilibrium (Neuman 1982; Neuman et al. 1979), and Talmage (1977) has also proposed disequilibrium between blood and bone. To investigate this problem, we have used techniques already used in the study of trans-capillary exchange to investigate whether transport of ions from the perivascular bone fluid can be controlled by cells lining bone surfaces.