粘多糖贮积症IIIA(MPSIIIA)是一种常染色体隐性遗传性溶酶体贮积症,由磺酰胺酶缺乏引起。该疾病导致硫酸乙酰肝素的积累,溶酶体肿大和细胞和器官功能障碍。患者表现出进行性神经变性和行为问题,目前尚无治疗方法。探索酶替代疗法作为MPSIIIA患者的潜在治疗策略,并改善疾病,磺酰胺酶必须到达大脑。重组人磺酰胺酶(rhSulfamidase)的聚糖可以被化学修饰以产生CM-rhSulfamidase。化学修饰降低了对阳离子非依赖性甘露糖-6-磷酸受体的亲和力,目的是在循环中并因此在血脑屏障中延长更高的浓度。研究了化学修饰的重组人磺酰胺酶(CM-rhSulfamidase)在血清中的药代动力学特性以及在脑和脑脊液(CSF)中的分布,并将其与rhSulfamidase进行了比较。在清醒时单次静脉注射(静脉内)30mg/kg剂量后,自由活动的雄性SpragueDawley老鼠.通过对前额叶皮层的间质液进行微透析,并从大脑池重复进行个体内CSF采样,研究了大脑的分布。推挽式微透析有助于脑间质液的采样,以确定清醒时的大分子浓度,自由活动的雄性SpragueDawley老鼠.再加上反复的血清和脑脊液取样,推挽式微透析有助于通过非隔室分析和群体建模方法在静脉内给药后测定CM-rhSulfamidase和rhSulfamidase动力学。化学修饰增加了血清中浓度与时间的关系,CSF和脑间质液至少7倍。浓度对时间数据的群体建模方法的结果和结果表明,两种化合物在施用后相当快速地建立平衡的情况下通过BBB。我们建议长时间的高血清浓度促进高脑间质液浓度,这可能有利于到达大脑中的各种靶细胞。
Mucopolysaccharidosis III A (MPS IIIA) is an autosomal recessive lysosomal storage disorder caused by deficiency of the enzyme sulfamidase. The disorder results in accumulation of heparan sulfate, lysosomal enlargement and cellular and organ dysfunction. Patients exhibit progressive neurodegeneration and behavioral problems and no treatment is currently available. Enzyme replacement therapy is explored as potential treatment strategy for MPS IIIA patients and to modify the disease, sulfamidase must reach the brain. The glycans of recombinant human sulfamidase (rhSulfamidase) can be chemically modified to generate CM-rhSulfamidase. The chemical modification reduced the affinity to the cation-independent mannose-6-phosphate receptor with the aim a prolonged higher concentration in circulation and thus at the blood brain barrier. The pharmacokinetic properties in serum and the distribution to brain and to cerebrospinal fluid (CSF) of chemically modified recombinant human sulfamidase (CM-rhSulfamidase) were studied and compared to those of rhSulfamidase, after a single intravenous (i.v.) 30 mg/kg dose in awake, freely-moving male Sprague Dawley rats. Distribution to brain was studied by microdialysis of the interstitial fluid in prefrontal cortex and by repeated intra-individual CSF sampling from the cisterna magna. Push-pull microdialysis facilitated sampling of brain interstitial fluid to determine large molecule concentrations in awake, freely-moving male Sprague Dawley rats. Together with repeated serum and CSF sampling, push-pull microdialysis facilitated determination of CM-rhSulfamidase and rhSulfamidase kinetics after i.v. administration by non-compartments analysis and by a population modelling approach. Chemical modification increased the area under the concentration versus time in serum, CSF and brain interstitial fluid at least 7-fold. The results and the outcome of a population modelling approach of the concentration versus time data indicated that both compounds pass the BBB with an equilibrium established fairly rapid after administration. We suggest that prolonged high serum concentrations facilitated high brain interstitial fluid concentrations, which could be favorable to reach various target cells in the brain.