Filtration rate dependence of hyaluronan reflection by joint-to-lymph barrier: evidence for concentration polarisation
Hyaluronan (HA), a component of synovial fluid, buffers fluid loss from joints. To explain this, a quantitative theory for HA concentration polarisation at a partially sieving synovial lining was developed. The theory predicts a fall in HA reflected fraction R with increased filtration rate. To test...
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Published in | The Journal of physiology Vol. 557; no. 3; pp. 909 - 922 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
9600 Garsington Road , Oxford , OX4 2DQ , UK
The Physiological Society
15.06.2004
Blackwell Science Ltd Blackwell Science Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Hyaluronan (HA), a component of synovial fluid, buffers fluid loss from joints. To explain this, a quantitative theory for
HA concentration polarisation at a partially sieving synovial lining was developed. The theory predicts a fall in HA reflected
fraction R with increased filtration rate. To test this, knees of anaesthetised rabbits were infused with HA and fluoresceinâdextran
(FD) at constant trans-synovial filtration rates of 6â89 μl min â1 . Samples of femoral lymph, mixed intra-articular fluid and subsynovial fluid after ⥠3 h were analysed by high-performance
liquid chromatography. R was calculated as (1 â downstream/upstream concentration), using [FD] to adjust for joint lymph dilution in femoral lymph.
Intra-articular HA concentration after ⥠3 h, 0.47 ± 0.02 mg ml â1 (mean ± s.e.m. , n = 31), exceeded the infusate concentration, 0.20 mg ml â1 , while subsynovial and lymph [HA] were reduced relative to [FD]. The changes in [HA] demonstrated synovial molecular sieving
of HA. R from cavity to lymph ( R lymph ) fell monotonically from 0.93 at 6 μl min â1 to 0.14 at 89 μl min â1 ( P < 0.0001, regression analysis, n = 33). R values calculated from the intra-articular HA accumulation ( R asp ) or the low subsynovial concentrations ( R syn ) were similar negative functions of filtration rate. R for lymphatic capillary endothelium ( R endo ), calculated from lymph/subsynovial concentration ratios, was effectively zero (â0.03 ± 0.18, n = 21), confirming that synovium, not initial lymphatic endothelium, is the reflection site. Logarithmic linearisation of the
results evaluated the synovial HA reflection coefficient as 0.91. In conclusion, the existence of concentration polarisation
during joint fluid drainage was supported by the demonstration of a negative relation between filtration rate and R lymph , R asp and R syn . |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2004.063529 |