Plasma concentrations of syndecan-1 are dependent on kidney function.

BACKGROUND

Elevated plasma concentrations of syndecan-1 and heparan sulfate in studies of trauma, sepsis, and major surgery are commonly assumed to indicate acute glycocalyx degradation. We explored a possible role of the kidneys for these elevations.

METHODS

Plasma and urine concentrations of syndecan-1, heparan sulfate, and biomarkers of inflammation were measured over 5 hours in 15 hospital patients treated for post-burn injury. The renal clearances of syndecan-1 and heparan sulfate (CL ) were calculated and their influence on the plasma concentration predicted by simulation.

RESULTS

The urine/plasma concentration ratio was 0.9 (0.3-3.0) for syndecan-1 and 2.8 (2.0-4.3) for heparan sulfate. The CL varied 250-fold for syndecan-1 and 10-fold for heparan sulfate. Multiple linear regression analysis showed that CL for syndecan-1 was positively associated with the creatinine clearance (P < .0032) and the urine flow (P < .015). CL for heparan sulfate increased with interleukin-6 (P < .003) and the urine flow (P < .01). Simulations suggested that a change in CL from the mean of the highest 3 to the lowest three values would double plasma syndecan-1 within 4 hours and cause a 7-fold rise after 24 hours. A similar change in CL for heparan sulfate would triple the plasma level within 24 hours, even if no increased shedding of the glycocalyx takes place.

CONCLUSIONS

The renal elimination of syndecan-1 and heparan sulfate varied greatly. A change in kidney function, which is common after trauma and major surgery, might alone induce several-fold changes in their plasma concentrations.