Torsteinsdottir I, Groth T, Lindqvist U
Department of Clinical Chemistry, University Hospital, Uppsala, Sweden.
Semin Arthritis Rheum. 1999 Feb;28(4):268-79. doi: 10.1016/s0049-0172(99)80022-5.
To evaluate the benefit of determining the maximal elimination rate (Vmax) and the endogenous production of hyaluronan (HYA) in relation to the basal HYA concentration (c0) in rheumatoid arthritis (RA) patients; and to evaluate the compatibility of a new model for HYA kinetics, taking renal elimination into separate account in the overall clearance of HYA from the blood.
The calculations of production and elimination of HYA were based on the HYA loading test, which was performed in 21 patients with RA and 15 healthy controls. A blood sample was drawn before the loading test, followed by an intravenous (i.v.) injection of HYA as a single bolus dose of 7.5 mg. Blood samples were taken regularly during the next 60 minutes. A theoretical model with computational analysis of the data collected was used for calculating HYA production and elimination.
Patients with RA had significantly higher c0 than healthy controls, although in 10 of 21 patients c0 was within the normal range. The RA patients also had higher Vmax than healthy controls, but the difference was not significant. The calculated production of HYA was increased in RA patients (P = .001) and correlated with c0 (P < .0001). The new model for HYA kinetics, in which the renal elimination was taken separately into account, proved to be more compatible than the previous model.
The HYA loading test can help determine whether the increased serum level of HYA in RA patients is due to a high production or reduced elimination of HYA or both.
评估测定类风湿关节炎（RA）患者的最大清除率（Vmax）和透明质酸（HYA）内源性生成量与基础HYA浓度（c0）的关系的益处；并评估一种新的HYA动力学模型的兼容性，该模型在从血液中清除HYA的总体清除率中单独考虑肾脏清除情况。
HYA生成和清除的计算基于HYA负荷试验，该试验在21例RA患者和15名健康对照者中进行。在负荷试验前采集一份血样，随后静脉注射（i.v.）7.5mg单剂量推注的HYA。在接下来的60分钟内定期采集血样。使用对收集的数据进行计算分析的理论模型来计算HYA的生成和清除。
RA患者的c0显著高于健康对照者，尽管21例患者中有10例的c0在正常范围内。RA患者的Vmax也高于健康对照者，但差异不显著。RA患者中计算出的HYA生成量增加（P = 0.001），且与c0相关（P < 0.0001）。新的HYA动力学模型，其中单独考虑了肾脏清除，被证明比先前的模型更具兼容性。
HYA负荷试验有助于确定RA患者血清HYA水平升高是由于HYA生成量高还是清除减少或两者兼而有之。
