Hybrid Nanoparticles as a Novel Tool for Regulating Psychosine-Induced Neuroinflammation and Demyelination In Vitro and Ex vivo

Polymeric nanoparticles are being extensively investigated as an approach for brain delivery of drugs, especially for their controlled release and targeting capacity. Nose-to-brain administration of nanoparticles, bypassing the blood brain barrier, offers a promising strategy to deliver drugs to the central nervous system. Here, we investigated the potential of hybrid nanoparticles as a therapeutic approach for demyelinating diseases, more specifically for Krabbe’s disease. This rare leukodystrophy is characterized by the lack of enzyme galactosylceramidase, leading to the accumulation of toxic psychosine in glial cells causing neuroinflammation, extensive demyelination and death. We present evidence that lecithin/chitosan nanoparticles prevent damage associated with psychosine by sequestering the neurotoxic sphingolipid via physicochemical hydrophobic interactions. We showed how nanoparticles prevented the cytotoxicity caused by psychosine in cultured human astrocytes in vitro, and how the nanoparticle size and PDI augmented while the electrostatic charges of the surface decreased, suggesting a direct interaction between psychosine and the nanoparticles. Moreover, we studied the effects of nanoparticles ex vivo using mouse cerebellar organotypic cultures, observing that nanoparticles prevented the demyelination and axonal damage caused by psychosine, as well as a moderate prevention of the astrocytic death. Taken together, these results suggest that lecithin-chitosan nanoparticles are a potential novel delivery system for drugs for certain demyelinating conditions such as Krabbe’s disease, due to their dual effect: not only are they an efficient platform for drug delivery, but they exert a protective effect themselves in tampering the levels of psychosine accumulation.

Krabbe’s Disease mutation spectrum in Russian Federation

Болезнь Краббе (БКр) - редкое наследственное аутосомно-рецессивное заболевание, входящее в группу лизосомных болезней накопления. Заболевание обусловлено мутациями в гене GALC, приводящими к дефициту фермента галактозилцерамидазы. Частота БКр оценивается как 1:100 000 живых новорожденных, хотя в некоторых странах регистрируется более высокая частота заболевания. Точная частота БКр в Российской Федерации и в ее регионах неизвестна. Мажорной мутацией, приводящей к развитию БКр, является крупная делеция затрагивающая 11-17 экзоны гена GALC c.1161+6532_polyA+9kbdel (IVS10del30kb). Доля этой мутации в европейской популяции оценивается примерно в 50% от всех мутаций. Для изучения спектра и частот мутаций гена GALC на территории РФ были обследованы пациенты из разных регионов. Частая делеция составила 54% от общего числа выявленных мутаций, что сопоставимо с данными по европейской популяции. Однако в Чеченской Республике данная мутация встречалась гораздо чаще, чем в других регионах. Среди 950 исследованных образцов было выявлено 7 гетерозиготных носителей частой мутации. Учитывая вклад других мутаций, расчётная частота БКр в республике составила 1:51237, что превышает таковую в европейской популяции. Дополнительный анализ всех найденных мутаций гена GALC позволил выявить вариант c.578T>C, p.Ile193Thr, аллельная частота которого составила 8%. Данная замена впервые была описана у пациентов из нашей выборки и встречается только при поздней инфантильной форме заболевания у русских пациентов. Krabbe’s disease (KD) is a rare inherited autosomal recessive lysosomal storage disease. KD is caused by mutations in the GALC gene leading to deficiency of galactosylceramidase. KD oссurs in 1 per 100 000 newborns, although some countries have a higher incidence rate. The exact KD incidence in Russia is unknown. A major mutation leading to the KD development is a large deletion affecting exons 11-17 of the GALC gene с.1161+6532_polyA+9kbdel (IVS10del30kb). This mutation occurs in 50% of KD cases in the European population. Patients from different regions were studied to analyze the mutation spectrum and the incidence in the Russian population. The incidence rate of the large deletion in our study equals 54%, that is comparable with European population. However, in the Chechen Republic this mutation is much more common than in other regions. 950 samples were studied, 7 heterozygous carriers of frequent mutation were identified. Thus, the estimated KD incidence rate is 1:51237 considering other mutations, and it is higher than that in the European population. Additional analysis of all detected GALC mutations revealed a genetic variant c.578T>C, p.Ile193Thr with allelic frequency measured up 8%. This substitution was described in our selection for the first time and presented only in Russian patients with late infantile form of the disease.

057 A rare presentation of a rare disease: adult onset krabbe’s disease presenting with progressive hypertrophic polyradiculoneuropathy

IntroductionGloboid Cell Leukodystrophy (Krabbe’s disease) is a rare autosomal recessive condition caused by defects in the lysosomal enzyme galactosylceramidase. The disease typically occurs in infants and is rapidly progressive. Fewer than 5% of cases develop symptoms in adulthood, the majority of which present with spastic paraparesis.CaseA 40-year-old Italian man presented with a 20 year history of gradually progressive asymmetrical hand paraesthesias and weakness. EMG demonstrated demyelinating features and absent sensory responses. CSF examination revealed elevated protein with no cells and negative oligoclonal bands. Treatment with intravenous immunoglobulin (IVIg) was commenced and continued for 2 years for presumed CIDP without clinical response. Upper limb wasting and weakness progressed over the following 10 years with associated loss of reflexes, prompting consideration of an underlying genetic neuropathy. DNA testing for common CMT mutations was negative. MRI cervical spine and brachial plexus demonstrated diffuse bilateral non-enhancing enlargement of cervical nerve roots. IVIg was recommenced over the next 10 years with continued clinical deterioration to the point of bilateral flail arms with relatively preserved lower limb motor function, in addition to bulbar and respiratory dysfunction by age 64. MRI brain demonstrated thickening of a number of cranial nerves without contrast enhancement, and extensive T2-hyperintensity of periventricular white matter. Next generation sequencing revealed two novel mutations in the galactosylceramidase (GALC) gene, and beta-galactocerebrosidase activity was reduced, confirming the diagnosis of Krabbe’s disease.ConclusionThis case highlights an unusual presentation of Krabbe’s disease with progressive hypertrophic polyradiculoneuropathy, associated with a novel genetic mutation.