The relative frequency of the Hurler and Hunter syndromes

Correction of CNS defects in the MPSII mouse model via systemic enzyme replacement therapy

Mucopolysaccharidosis type II (MPSII), or Hunter syndrome, is a devastating disorder associated with a shortened life expectancy. Patients affected by MPSII have a variety of symptoms that affect all organs of the body and may include progressive cognitive impairment. MPSII is due to inactivity of the enzyme iduronate-2-sulfatase (IDS), which results in the accumulation of storage material in the lysosomes, such as dermatan and heparan sulfates, with consequent cell degeneration in all tissues including, in the severe phenotype, neurodegeneration in the central nervous system (CNS). To date, the only treatment available is systemic infusion of IDS, which ameliorates exclusively certain visceral defects. Therefore, it is important to simultaneously treat the visceral and CNS defects of the MPSII patients. Here, we have developed enzyme replacement therapy (ERT) protocols in a mouse model that allow the IDS to reach the brain, with the substantial correction of the CNS phenotype and of the neurobehavioral features. Treatments were beneficial even in adult and old MPSII mice, using relatively low doses of infused IDS over long intervals. This study demonstrates that CNS defects of MPSII mice can be treated by systemic ERT, providing the potential for development of an effective treatment for MPSII patients.

Preclinical dose ranging studies for enzyme replacement therapy with idursulfase in a knock-out mouse model of MPS II

Mucopolysaccharidosis II (MPS II; Hunter syndrome) is an X-linked metabolic disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S), which catalyzes the catabolism of glycosaminoglycans (GAG) by cleaving the O-linked sulfate from dermatan sulfate and heparan sulfate. Recently, enzyme replacement therapy (ERT) with recombinant human I2S (Elaprase (idursulfase), Shire Human Genetic Therapies, Inc.), has been approved in the US and European Union for the treatment and management of MPS II. The purpose of the studies presented here was to describe some of the preclinical development of idursulfase using the I2S knock-out mouse model of MPS II designed to study the effect of dose and various dosing regimens of idursulfase on urine and tissue GAG levels. Urine and tissue samples were collected prior to idursulfase treatment and periodically throughout each study and analyzed for GAGs. The presence of anti-idursulfase antibodies in the mice serum after idursulfase use was also determined. Results showed that idursulfase, at several doses and at several dosing frequencies, caused a reduction in tissue and urine GAG levels in a dose-dependent manner. These studies also demonstrated that after IV administration, idursulfase is biologically active in the IdS-KO mouse model and is transported to key target tissues, reaching the lysosomes in an active form, and degrading the accumulated GAG. In conclusion, these results indicated that ERT with idursulfase produced in a human cell line could be useful in the treatment and management of MPS II, and were used in the design of clinical studies to evaluate the efficacy of idursulfase in MPS II patients.

Reflections on eponyms in neuroscience terminology

Eponyms have played a very significant linguistic role in technical and scientific terminology. They are an important feature of language that have contributed for a long time to engraving in history the names of those researchers who have devoted their lives to scientific discovery. In the field of medical terminology, they are an asset, although their semantic effectiveness has constituted a long-standing debate. We will analyze how language contributes to the advance of science and technology and the current position of eponyms in the health sciences. Eponymy in neuroscience has been used for a long time as a way to identify and recognize scientific issues, such as diseases, syndromes, methods, processes, substances, organs, and parts of organs as a way to honor those who, in a certain way, contributed to the progress of science. However, sometimes those honors do not correspond to the real contributors, thus receiving a nondeserved acknowledgment. Another problem with eponymic references is the lack of information about the matter in hand, because eponyms do not provide any clear information leading to the identification of the situation under study, as they are not reasonably descriptive. The aim of this article is to encourage the use of descriptive terms instead of eponyms and to establish a system of scientific nomenclature to consolidate the use of the language as a means of conveying scientific information among experts.