Intrathecal 2-hydroxypropyl-beta-cyclodextrin in a single patient with Niemann-Pick C1

Cyclodextrins as therapeutic drugs for treating lipid metabolism disorders

OBJECTIVE

This study sought to systematically compare the efficacy and mechanism of cyclodextrins as drug interventions in lipid metabolism diseases, potentially providing ideas for subsequent research directions and clinical applications.

METHODS

We used the bibliometric method for feature mining, applied VOSviewer software for clustering analysis, and applied content analysis for objective descriptions and accurate analysis.

RESULTS

(1) We collected more than 50 studies, which is the basic database of this study. (2) The academic bubble map showed that this research area was popular in the United States. (3) Cluster analysis showed that the intensively studied diseases in this field were Niemann-Pick type C (NPC), atherosclerosis (AS), and obesity. The hot-spot cyclodextrin types were HP-β-CD. (4) Literature measurement revealed the involvement of 15 types of lipid metabolism diseases. Among them, NPC, diabetes, and obesity were studied in clinical trials. Dyslipidemia and AS have been reported relatively more frequently in animal experiments. The studies of cellular experiments provide insight into the molecular mechanisms that intervene in lipid metabolism diseases from multiple perspectives. The exploration of the molecular mechanisms by which cyclodextrins exert their pharmacological effects mainly revolves around lipid metabolism.

CONCLUSION

It is worthwhile to investigate the role and mechanism of cyclodextrins in other lipid metabolism diseases. The potential efficacy evaluation of cyclodextrins as pharmaceutical drugs for oral or injectable formulations is less studied and may become a new focus in the future.

Long-term administration of intravenous Trappsol® Cyclo™ (HP-β-CD) results in clinical benefits and stabilization or slowing of disease progression in patients with Niemann-Pick disease type C1: Results of an international 48-week Phase I/II trial

Background

Niemann-Pick disease type C (NPC) is a rare, fatal, pan-ethnic, autosomal recessive lysosomal storage disease characterized by progressive major organ failure and neurodegeneration. Preclinical studies confirmed a critical role of systemically administered hydroxypropyl-β-cyclodextrin (HP-β-CD; Trappsol® Cyclo™) in cholesterol metabolism and homeostasis in peripheral tissues of the body, including the liver, and in the central nervous system (CNS). Herein, the pharmacokinetics (PK), safety, and efficacy of HP-β-CD, and biomarkers of NPC were assessed in pediatric and adult patients with NPC1.

Methods

This was a multicenter, Phase I/II, randomized, double-blind, parallel-group, 48-week study (ClinicalTrials.gov identifier NCT02912793) to compare the PK of three different single intravenous (IV) doses of HP-β-CD in pediatric and adult patients with NPC1 and to evaluate the efficacy and tolerability of three different dosages of HP-β-CD in patients with NPC1 after long-term treatment. Twelve patients aged at least 2 years (2-39 years of age) with a confirmed diagnosis of NPC1 were randomized to receive one of three IV doses of HP-β-CD (1500 mg/kg, 2000 mg/kg, or 2500 mg/kg) every 2 weeks for 48 weeks. All patients received HP-β-CD; there was no placebo or other control. PK testing of plasma and cerebrospinal fluid (CSF) was at set times after the first infusion. Pharmacodynamic assessments included biomarkers of cholesterol metabolism (synthesis and breakdown products), N-palmitoyl-O-phosphocholineserine (PPCS), and specific biomarkers of CSF neurodegeneration (including total Tau), CNS inflammation (glial fibrillary acidic protein [GFAP] and tumor necrosis factor α [TNFα]), CNS cholesterol metabolism (24S-hydroxycholesterol) and inflammatory markers. Efficacy measures included clinical disease severity, neurologic symptoms, and clinical impressions of improvement. Safety assessment included physical examination, vital signs, clinical safety laboratory assessment and adverse events (AEs).

Results

Nine patients completed the study, 2 in the 1500 mg/kg group, 4 in the 2000 mg/kg group and 3 in the 2500 mg/kg group. Three patients (all in the 1500 mg/kg group) discontinued the study because of either physician decision/site Principal Investigator (PI) discretion, withdrawal by subject/patient/parent/guardian, or other non-safety reasons. In 5 patients who underwent serial lumbar punctures, HP-β-CD was detected in the CSF. Of the 9 patients who completed the study, 8 (88.9%) improved in at least two domains of the 17-Domain Niemann-Pick disease Type C-Clinical Severity Scale (17D-NPC-CSS), and 6 of these patients improved in at least one domain viewed by patients and their caregivers to be key to quality of life, namely, speech, swallow, fine and gross motor skills, and cognition. Of the 9 patients who completed the study, 7 were viewed by their treating physicians as having improved to some degree at the end of the study, and 2 remained stable; both outcomes are highly relevant in a progressive neurodegenerative disease. Some patients and families reported improvement in quality of life.All three doses of HP-β-CD were well tolerated overall, with most treatment-emergent adverse events transient, mild-to-moderate in nature, and considered by the site PIs to be not related to study drug.

Interpretation

This 48-week trial is the longest to date to evaluate the safety, tolerability, and efficacy across multiple clinical endpoints of IV administration of Trappsol® Cyclo™ (HP-β-CD) in NPC1 patients. In pediatric and adult patients with NPC, Trappsol® Cyclo™ IV improved clinical signs and symptoms and was generally well tolerated. The findings presented here demonstrate a favorable benefit-risk profile and support the global pivotal trial now underway to evaluate the long-term treatment benefits and the potential of Trappsol® Cyclo™ as a disease-modifying treatment in this patient population.

Lysosomal cholesterol accumulation is commonly found in most peroxisomal disorders and reversed by 2-hydroxypropyl-β-cyclodextrin

Peroxisomal disorders (PDs) are a heterogenous group of diseases caused by defects in peroxisome biogenesis or functions. X-linked adrenoleukodystrophy is the most prevalent form of PDs and results from mutations in the ABCD1 gene, which encodes a transporter mediating the uptake of very long-chain fatty acids (VLCFAs). The curative approaches for PDs are very limited. Here, we investigated whether cholesterol accumulation in the lysosomes is a biochemical feature shared by a broad spectrum of PDs. We individually knocked down fifteen PD-associated genes in cultured cells and found ten induced cholesterol accumulation in the lysosome. 2-Hydroxypropyl-β-cyclodextrin (HPCD) effectively alleviated the cholesterol accumulation phenotype in PD-mimicking cells through reducing intracellular cholesterol content as well as promoting cholesterol redistribution to other cellular membranes. In ABCD1 knockdown cells, HPCD treatment lowered reactive oxygen species and VLCFA to normal levels. In Abcd1 knockout mice, HPCD injections reduced cholesterol and VLCFA sequestration in the brain and adrenal cortex. The plasma levels of adrenocortical hormones were increased and the behavioral abnormalities were greatly ameliorated upon HPCD administration. Together, our results suggest that defective cholesterol transport underlies most, if not all, PDs, and that HPCD can serve as a novel and effective strategy for the treatment of PDs.

Polymer-based drug delivery systems under investigation for enzyme replacement and other therapies of lysosomal storage disorders

Lysosomes play a central role in cellular homeostasis and alterations in this compartment associate with many diseases. The most studied example is that of lysosomal storage disorders (LSDs), a group of 60 + maladies due to genetic mutations affecting lysosomal components, mostly enzymes. This leads to aberrant intracellular storage of macromolecules, altering normal cell function and causing multiorgan syndromes, often fatal within the first years of life. Several treatment modalities are available for a dozen LSDs, mostly consisting of enzyme replacement therapy (ERT) strategies. Yet, poor biodistribution to main targets such as the central nervous system, musculoskeletal tissue, and others, as well as generation of blocking antibodies and adverse effects hinder effective LSD treatment. Drug delivery systems are being studied to surmount these obstacles, including polymeric constructs and nanoparticles that constitute the focus of this article. We provide an overview of the formulations being tested, the diseases they aim to treat, and the results observed from respective in vitro and in vivo studies. We also discuss the advantages and disadvantages of these strategies, the remaining gaps of knowledge regarding their performance, and important items to consider for their clinical translation. Overall, polymeric nanoconstructs hold considerable promise to advance treatment for LSDs.

Alterations in Cholesterol and Phosphoinositides Levels in the Intracellular Cholesterol Trafficking Disorder NPC

Lipid mistrafficking is a biochemical hallmark of Niemann-Pick Type C (NPC) disease and is classically characterized with endo/lysosomal accumulation of unesterified cholesterol due to genetic mutations in the cholesterol transporter proteins NPC1 and NPC2. Storage of this essential signaling lipid leads to a sequence of downstream events, including oxidative stress, calcium imbalance, neuroinflammation, and progressive neurodegeneration, another hallmark of NPC disease. These observations have been validated in a growing number of studies ranging from NPC cell cultures and animal models to patient specimens. In recent reports, alterations in the levels of another class of critical signaling lipids, namely phosphoinositides, have been described in NPC disease. Focusing on cholesterol and phosphoinositides, the chapter begins by reviewing the interactions of NPC proteins with cholesterol and their role in cholesterol transport. It then continues to describe the modulation of cholesterol efflux in NPC disease. The chapter concludes with a summary of findings related to the functional consequences of perturbations in phosphoinositides in this fatal disease.

Cyclodextrins applied to the treatment of lysosomal storage disorders

Cyclodextrin (CD), a cyclic oligosaccharide, is a pharmaceutical additive that improves the solubility of hydrophobic compounds. Recent research has focused on the potential active pharmaceutical abilities of CD. Lysosomal storage diseases are inherited metabolic diseases characterized by lysosomal dysfunction and abnormal lipid storage. Niemann-Pick disease type C (NPC) is caused by mutations in cholesterol transporter genes (NPC1, NPC2) and is characterized by cholesterol accumulation in lysosomes. A biocompatible cholesterol solubilizer 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was recently used in NPC patients for compassionate use and in clinical trials. HP-β-CD is an attractive drug candidate for NPC; however, its adverse effects, such as ototoxicity, should be solved. In this review, we discuss the current use of HP-β-CD in basic and clinical research and discuss alternative CD derivatives that may outperform HP-β-CD, which should be considered for clinical use. The potential of CD therapy for the treatment of other lysosomal storage diseases is also discussed.

Cyclodextrins: Only Pharmaceutical Excipients or Full-Fledged Drug Candidates?

Cyclodextrins, representing a versatile family of cyclic oligosaccharides, have extensive pharmaceutical applications due to their unique truncated cone-shaped structure with a hydrophilic outer surface and a hydrophobic cavity, which enables them to form non-covalent host-guest inclusion complexes in pharmaceutical formulations to enhance the solubility, stability and bioavailability of numerous drug molecules. As a result, cyclodextrins are mostly considered as inert carriers during their medical application, while their ability to interact not only with small molecules but also with lipids and proteins is largely neglected. By forming inclusion complexes with cholesterol, cyclodextrins deplete cholesterol from cellular membranes and thereby influence protein function indirectly through alterations in biophysical properties and lateral heterogeneity of bilayers. In this review, we summarize the general chemical principles of direct cyclodextrin-protein interactions and highlight, through relevant examples, how these interactions can modify protein functions in vivo, which, despite their huge potential, have been completely unexploited in therapy so far. Finally, we give a brief overview of disorders such as Niemann-Pick type C disease, atherosclerosis, Alzheimer's and Parkinson's disease, in which cyclodextrins already have or could have the potential to be active therapeutic agents due to their cholesterol-complexing or direct protein-targeting properties.

Lactose-Appended Hydroxypropyl-β-Cyclodextrin Lowers Cholesterol Accumulation and Alleviates Motor Dysfunction in Niemann-Pick Type C Disease Model Mice

Niemann-Pick disease type C (NPC) is characterized by the accumulation of glycolipids such as free cholesterol, sphingomyelin, and gangliosides in late endosomes/lysosomes (endolysosomes) due to abnormalities in the membrane proteins NPC1 or NPC2. The main symptoms of NPC caused by free cholesterol accumulation in various tissues vary depending on the time of onset, but hepatosplenomegaly and neurological symptoms accompanied by decreased motor, cognitive, and mental functions are observed in all age groups. However, the efficacy of NPC treatment remains limited. Herein, we have fabricated lactose-appended hydroxypropyl-β-cyclodextrin (Lac-HPβCD) and evaluated its lowering effects on cholesterol accumulation in NPC model mice. We reveal that Lac-HPβCD lowers cholesterol accumulation in the liver and spleen by reducing the amount of free cholesterol. Moreover, Lac-HPβCD reduces the amount of free cholesterol in the cerebrum and slightly alleviates motor dysfunction. These results suggest that Lac-HPβCD has potential for the treatment of NPC.

Combined antioxidants and anti-inflammatory therapies fail to attenuate the early and late phases of cyclodextrin-induced cochlear damage and hearing loss

Niemann-Pick C1 (NPC1) is a fatal neurodegenerative disease caused by aberrant cholesterol metabolism. The progression of the disease can be slowed by removing excess cholesterol with high-doses of 2-hyroxypropyl-beta-cyclodextrin (HPβCD). Unfortunately, HPβCD causes hearing loss; the initial first phase involves a rapid destruction of outer hair cells (OHCs) while the second phase, occurring 4-6 weeks later, involves the destruction of inner hair cells (IHCs), pillar cells, collapse of the organ of Corti and spiral ganglion neuron degeneration. To determine whether the first and/or second phase of HPβCD-induced cochlear damage is linked, in part, to excess oxidative stress or neuroinflammation, rats were treated with a single-dose of 3000 mg/kg HPβCD alone or together with one of two combination therapies. Each combination therapy was administered from 2-days before to 6-weeks after the HPβCD treatment. Combination 1 consisted of minocycline, an antibiotic that suppresses neuroinflammation, and HK-2, a multifunctional redox modulator that suppresses oxidative stress. Combination 2 was comprised of minocycline plus N-acetyl cysteine (NAC), which upregulates glutathione, a potent antioxidant. To determine if either combination therapy could prevent HPβCD-induced hearing impairment and cochlear damage, distortion product otoacoustic emissions (DPOAE) were measured to assess OHC function and the cochlear compound action potential (CAP) was measured to assess the function of IHCs and auditory nerve fibers. Cochleograms were prepared to quantify the amount of OHC, IHC and pillar cell (PC) loss. HPβCD significantly reduced DPOAE and CAP amplitudes and caused significant OHC, IHC and OPC losses with losses greater in the high-frequency base of the cochlea than the apex. Neither minocycline + HK-2 (MIN+ HK-2) nor minocycline + NAC (MIN+NAC) prevented the loss of DPOAEs, CAPs, OHCs, IHCs or IPCs caused by HPβCD. These results suggest that oxidative stress and neuroinflammation are unlikely to play major roles in mediating the first or second phase of HPβCD-induced cochlear damage. Thus, HPβCD-induced ototoxicity must be mediated by some other unknown cell-death pathway possibly involving loss of trophic support from damaged support cells or disrupted cholesterol metabolism.

Impacts and Burden of Niemann pick Type-C: a patient and caregiver perspective

Background

Niemann-Pick disease type C (NPC) is a debilitating condition that impacts patients’ and caregivers’ quality of life (QOL) and reduces the patient’s life expectancy. Since there is little qualitative research from the perspective of patients and family caregivers, this study explored the impact of NPC on patients’ and caregivers’ daily lives to understand the burden of disease.

Results

A survey of caregivers for patients with NPC and adult patients with NPC (n = 49; patient age: 13 months–65 years) assessed NPC severity, importance of NPC symptoms, and how symptoms impacted patients’ and caregivers’ activities of daily living (ADLs) and health-related QOL (HRQOL). Follow-up interviews with a subset of survey participants (n = 28) explored the ranking of NPC symptom importance and impact on ADLs and HRQOL. Findings indicated that the most important manifestations of NPC were ambulation, swallowing, speech, fine motor skills, and cognition, which were those that had the most significant impact on ADLs and HRQOL. A wide range of ADLs were affected by NPC, mainly eating/drinking and the ability to perform daily tasks, including self-care, communicating, participating in school or work, and moving indoors as well as outside the home. Along with these impacts, there was an increased risk of experiencing dangerous or life-threatening situations leading to loss of patient independence and additional caregiver burden, often requiring changes in lifestyle such as giving up work. All aspects of patients’ and caregivers’ HRQOL were affected. Participants reported feelings of social isolation, loss of enjoyment in activities (patients), and feelings of sadness or worry (caregivers).

Conclusions

Ambulation, swallowing, speech, fine motor skills, and cognition are important manifestations of NPC. ADLs and HRQOL were impaired in the majority of patients as well as their caregivers. The findings were independent of current age, age of onset of symptoms, and level of NPC disease-related disability; however, the impact increased at higher levels of disease disability. Knowing the impact of NPC on patients and caregivers is important for understanding the lived experience of NPC and for identifying potential areas of support.

Enrichment of NPC1-deficient cells with the lipid LBPA stimulates autophagy, improves lysosomal function, and reduces cholesterol storage

Niemann-Pick C (NPC) is an autosomal recessive disorder characterized by mutations in the NPC1 or NPC2 genes encoding endolysosomal lipid transport proteins, leading to cholesterol accumulation and autophagy dysfunction. We have previously shown that enrichment of NPC1-deficient cells with the anionic lipid lysobisphosphatidic acid (LBPA; also called bis(monoacylglycerol)phosphate) via treatment with its precursor phosphatidylglycerol (PG) results in a dramatic decrease in cholesterol storage. However, the mechanisms underlying this reduction are unknown. In the present study, we showed using biochemical and imaging approaches in both NPC1-deficient cellular models and an NPC1 mouse model that PG incubation/LBPA enrichment significantly improved the compromised autophagic flux associated with NPC1 disease, providing a route for NPC1-independent endolysosomal cholesterol mobilization. PG/LBPA enrichment specifically enhanced the late stages of autophagy, and effects were mediated by activation of the lysosomal enzyme acid sphingomyelinase. PG incubation also led to robust and specific increases in LBPA species with polyunsaturated acyl chains, potentially increasing the propensity for membrane fusion events, which are critical for late-stage autophagy progression. Finally, we demonstrated that PG/LBPA treatment efficiently cleared cholesterol and toxic protein aggregates in Purkinje neurons of the NPC1I1061T mouse model. Collectively, these findings provide a mechanistic basis supporting cellular LBPA as a potential new target for therapeutic intervention in NPC disease.

Harnessing cerebrospinal fluid circulation for drug delivery to brain tissues

Initially thought to be useful only to reach tissues in the immediate vicinity of the CSF circulatory system, CSF circulation is now increasingly viewed as a viable pathway to deliver certain therapeutics deeper into brain tissues. There is emerging evidence that this goal is achievable in the case of large therapeutic proteins, provided conditions are met that are described herein. We show how fluid dynamic modeling helps predict infusion rate and duration to overcome high CSF turnover. We posit that despite model limitations and controversies, fluid dynamic models, pharmacokinetic models, preclinical testing, and a qualitative understanding of the glymphatic system circulation can be used to estimate drug penetration in brain tissues. Lastly, in addition to highlighting landmark scientific and medical literature, we provide practical advice on formulation development, device selection, and pharmacokinetic modeling. Our review of clinical studies suggests a growing interest for intra-CSF delivery, particularly for targeted proteins.

Spatiotemporal Developmental Upregulation of Prestin Correlates With the Severity and Location of Cyclodextrin-Induced Outer Hair Cell Loss and Hearing Loss

2-Hyroxypropyl-beta-cyclodextrin (HPβCD) is being used to treat Niemann-Pick C1, a fatal neurodegenerative disease caused by abnormal cholesterol metabolism. HPβCD slows disease progression, but unfortunately causes severe, rapid onset hearing loss by destroying the outer hair cells (OHC). HPβCD-induced damage is believed to be related to the expression of prestin in OHCs. Because prestin is postnatally upregulated from the cochlear base toward the apex, we hypothesized that HPβCD ototoxicity would spread from the high-frequency base toward the low-frequency apex of the cochlea. Consistent with this hypothesis, cochlear hearing impairments and OHC loss rapidly spread from the high-frequency base toward the low-frequency apex of the cochlea when HPβCD administration shifted from postnatal day 3 (P3) to P28. HPβCD-induced histopathologies were initially confined to the OHCs, but between 4- and 6-weeks post-treatment, there was an unexpected, rapid and massive expansion of the lesion to include most inner hair cells (IHC), pillar cells (PC), peripheral auditory nerve fibers, and spiral ganglion neurons at location where OHCs were missing. The magnitude and spatial extent of HPβCD-induced OHC death was tightly correlated with the postnatal day when HPβCD was administered which coincided with the spatiotemporal upregulation of prestin in OHCs. A second, massive wave of degeneration involving IHCs, PC, auditory nerve fibers and spiral ganglion neurons abruptly emerged 4–6 weeks post-HPβCD treatment. This secondary wave of degeneration combined with the initial OHC loss results in a profound, irreversible hearing loss.

Longitudinal Data in Patients with Niemann-Pick Type C Disease Under Combined High Intrathecal and Low Intravenous Dose of 2-hydroxylpropyl-β-cyclodextrin

Niemann-Pick Type C disease (NPC) is a rare, incurable, autosomal-recessive, lysosomal storage disorder with protean and progressive neurovisceral manifestations characterized by accumulation of intracellular unesterified cholesterol. The investigational use of 2-hydroxypropyl-beta-cyclodextrin (HP-β-CD) in the treatment of NPC has shown promising results in improving life expectancy and reducing neurological damage in this patient population. This case report describes two children with the neurological form of NPC: a 5-year-old male patient in advanced stage of the disease and an 11-year-old female patient in moderately advanced stage. Despite treatment with the enzyme inhibitor, miglustat, both patients continued to exhibit severe neurodegeneration. High intrathecal (900mg) and low intravenous (350-500mg/kg) doses of HP-β-CD (Trappsol®Cyclo™) were administrated twice monthly to the patients in addition to miglustat therapy. The patients were monitored clinically as well as by imaging, laboratory, and biomarker (e.g., total tau protein [T-tau]; phosphorylated tau [P-tau]; neurofilament light [NFL], oxysterols) studies over a period of 16 to 22 months. The combination therapy of miglustat and HP-β-CD resulted in disease stabilization in both patients. The combination therapy demonstrated a good safety profile, and no adverse effects on hearing were observed. Additionally, CSF biomarkers appeared useful in monitoring neuronal damage. Large, randomized studies are needed to confirm these findings.

Application of a glycinated bile acid biomarker for diagnosis and assessment of response to treatment in Niemann-pick disease type C1

Niemann-Pick disease type C (NPC) is a neurodegenerative disease in which mutation of NPC1 or NPC2 gene leads to lysosomal accumulation of unesterified cholesterol and sphingolipids. Diagnosis of NPC disease is challenging due to non-specific early symptoms. Biomarker and genetic tests are used as first-line diagnostic tests for NPC. In this study, we developed a plasma test based on N-(3β,5α,6β-trihydroxy-cholan-24-oyl)glycine (TCG) that was markedly increased in the plasma of human NPC1 subjects. The test showed sensitivity of 0.9945 and specificity of 0.9982 to differentiate individuals with NPC1 from NPC1 carriers and controls. Compared to other commonly used biomarkers, cholestane-3β,5α,6β-triol (C-triol) and N-palmitoyl-O-phosphocholine (PPCS, also referred to as lysoSM-509), TCG was equally sensitive for identifying NPC1 but more specific. Unlike C-triol and PPCS, TCG showed excellent stability and no spurious generation of marker in the sample preparation or aging of samples. TCG was also elevated in lysosomal acid lipase deficiency (LALD) and acid sphingomyelinase deficiency (ASMD). Plasma TCG was significantly reduced after intravenous (IV) 2-hydroxypropyl-β-cyclodextrin (HPβCD) treatment. These results demonstrate that plasma TCG was superior to C-triol and PPCS as NPC1 diagnostic biomarker and was able to evaluate the peripheral treatment efficacy of IV HPβCD treatment.

Cochlear spiral ganglion neuron degeneration following cyclodextrin-induced hearing loss

Because cyclodextrins are capable of removing cholesterol from cell membranes, there is growing interest in using these compounds to treat diseases linked to aberrant cholesterol metabolism. One compound, 2-hydroxypropyl-beta-cyclodextrin (HPβCD), is currently being evaluated as a treatment for Niemann-Pick Type C1 disease, a rare, fatal neurodegenerative disease caused by the buildup of lipids in endosomes and lysosomes. HPβCD can reduce some debilitating symptoms and extend life span, but the therapeutic doses used to treat the disease cause hearing loss. Initial studies in rodents suggested that HPβCD selectively damaged only cochlear outer hair cells during the first week post-treatment. However, our recent in vivo and in vitro studies suggested that the damage could become progressively worse and more extensive over time. To test this hypothesis, we treated rats subcutaneously with 1, 2, 3 or 4 g/kg of HPβCD and waited for 8-weeks to assess the long-term histological consequences. Our new results indicate that the two highest doses of HPβCD caused extensive damage not only to OHC, but also to inner hair cells, pillar cells and other support cells resulting in the collapse and flattening of the sensory epithelium. The 4 g/kg dose destroyed all the outer hair cells and three-fourths of the inner hair cells over the basal two-thirds of the cochlea and more than 85% of the nerve fibers in the habenula perforata and more than 80% of spiral ganglion neurons in the middle of basal turn of the cochlea. The mechanisms that lead to the delayed degeneration of inner hair cells, pillar cells, nerve fibers and spiral ganglion neurons remain poorly understood, but may be related to the loss of trophic support caused by the degeneration of sensory and/or support cells in the organ of Corti. Despite the massive damage to the cochlear sensory epithelium, the blood vessels in the stria vascularis and the vestibular hair cells in the utricle and saccule remained normal.

Deregulation of signalling in genetic conditions affecting the lysosomal metabolism of cholesterol and galactosyl-sphingolipids

The role of lipids in neuroglial function is gaining momentum in part due to a better understanding of how many lipid species contribute to key cellular signalling pathways at the membrane level. The description of lipid rafts as membrane domains composed by defined classes of lipids such as cholesterol and sphingolipids has greatly helped in our understanding of how cellular signalling can be regulated and compartmentalized in neurons and glial cells. Genetic conditions affecting the metabolism of these lipids greatly impact on how some of these signalling pathways work, providing a context to understand the biological function of the lipid. Expectedly, abnormal metabolism of several lipids such as cholesterol and galactosyl-sphingolipids observed in several metabolic conditions involving lysosomal dysfunction are often accompanied by neuronal and myelin dysfunction. This review will discuss the role of lysosomal biology in the context of deficiencies in the metabolism of cholesterol and galactosyl-sphingolipids and their impact on neural function in three genetic disorders: Niemann-Pick type C, Metachromatic leukodystrophy and Krabbe’s disease.

Hydroxypropyl-β-cyclodextrin causes massive damage to the developing auditory and vestibular system

2-hydroxypropyl-β-cyclodextrin (HPβCD), a cholesterol chelator used to treat Niemann-Pick C1 (NPC1) lysosomal storage disease, causes hearing loss in mammals by preferentially destroying outer hair cells. Because cholesterol plays an important role in early neural development, we hypothesized that HPβCD would cause more extensive damage to postnatal cochlear and vestibular structures in than adult rats. This hypothesis was tested by administering HPβCD to adult rats and postnatal day 3 (P3) cochlear and vestibular organ cultures. Adult rats treated with HPβCD developed hearing impairment and outer hair cell loss 3-day post-treatment; damage increased with dose from the high frequency base toward the low-frequency apex. The HPβCD-induced histopathologies were more severe and widespread in cochlear and vestibular cultures at P3 than in adults. HPβCD destroyed both outer and inner hair cells, auditory nerve fibers and spiral ganglion neurons as well as type I and type II vestibular hair cells and vestibular ganglion neurons. The early stage of HPβCD damage involved disruption of hair cell mechanotransduction and destruction of stereocilia. HPβCD-mediated apoptosis in P3 cultures was most-strongly initiated by activation of the extrinsic caspase-8 cell death pathway in cochlear and vestibular hair cells and neurons followed by activation of executioner caspase-3. Thus, HPβCD is toxic to all types of postnatal cochlear and vestibular hair cells and neurons in vitro whereas in vivo it only appears to destroy outer hair cells in adult cochleae. The more severe HPβCD-induced damage in postnatal cultures could be due to greater drug bioavailability in vitro and/or greater vulnerability of the developing inner ear.

2-Hydroxypropyl-β-cyclodextrin Ototoxicity in Adult Rats: Rapid Onset and Massive Destruction of Both Inner and Outer Hair Cells Above a Critical Dose

2-Hydroxypropyl-β-cyclodextrin (HPβCD), a cholesterol chelator, is being used to treat diseases associated with abnormal cholesterol metabolism such as Niemann-Pick C1 (NPC1). However, the high doses of HPβCD needed to slow disease progression may cause hearing loss. Previous studies in mice have suggested that HPβCD ototoxicity results from selective outer hair cell (OHC) damage. However, it is unclear if HPβCD causes the same type of damage or is more or less toxic to other species such as rats, which are widely used in toxicity research. To address these issues, rats were given a subcutaneous injection of HPβCD between 500 and 4000 mg/kg. Distortion product otoacoustic emissions (DPOAE), the cochlear summating potential (SP), and compound action potential (CAP) were used to assess cochlear function followed by quantitative analysis of OHC and inner hair cell (IHC) loss. The 3000- and 4000-mg/kg doses abolished DPOAE and greatly reduced SP and CAP amplitudes. These functional deficits were associated with nearly complete loss of OHC as well as ~ 80% IHC loss over the basal two thirds of the cochlea. The 2000-mg/kg dose abolished DPOAE and significantly reduced SP and CAP amplitudes at the high frequencies. These deficits were linked to OHC and IHC losses in the high-frequency region of the cochlea. Little or no damage occurred with 500 or 1000 mg/kg of HPβCD. The HPβCD-induced functional and structural deficits in rats occurred suddenly, involved damage to both IHC and OHC, and were more severe than those reported in mice.

2-Hydroxypropyl-gamma-cyclodextrin overcomes NPC1 deficiency by enhancing lysosome-ER association and autophagy

Niemann-Pick type C (NPC) disease is a fatal neurodegenerative disorder caused by mutations in NPC1 and NPC2 genes that result in an accumulation of cholesterol in lysosomes. The majority of children with NPC die in adolescence. Currently, no FDA-approved therapies exist for NPC and the mechanisms of NPC disease are not fully understood. Our recent study and the reports from other laboratories showed that 2-hydroxypropyl-γ-cyclodextrin (HPγCD) alleviates cholesterol accumulation in NPC1-deficient cells in spite of its low binding affinity for cholesterol. In this study, we explored the cellular changes that are induced upon HPγCD treatment in NPC1 patient-derived fibroblasts. We show that HPγCD treatment increases lysosome-ER association and enhances autophagic activity. Our study indicates that HPγCD induces an activation of the transcription factor EB (TFEB), a master regulator of lysosomal functions and autophagy. Lysosome-ER association could potentially function as conduits for cholesterol transport from lysosomes to the ER. Accumulating evidence suggests a role for autophagy in rescuing the cholesterol accumulation in NPC and other degenerative diseases. Collectively, our findings suggest that HPγCD restores cellular homeostasis in NPC1-deficient cells via enhancing lysosomal dynamics and functions. Understanding the mechanisms of HPγCD-induced cellular pathways could contribute to effective NPC therapies.

Recent advances in the treatment of Niemann pick disease type C: A mini-review

Niemann Pick disease Type C (NPC) is a recessive rare disease caused by the mutation on NPC1 and/or NPC2 genes changing the processing of the Low-density proteins (LDL) resulting in an accumulation of lipids in the cells. Until today there is not a cure, the current treatment is based on palliative affairs to reduce the symptoms and prevent its appearance. Among all the treatments proposed the use of cyclodextrins (CDs), nanocarriers which can complex cholesterol, is one of the most useful alternatives. Indeed, for several years 2-hydroxypropyl-β-CD (HPβ-CD) is approved as orphan drug for FDA and EMA to the treatment. However, different CDs based materials are created each year to improve the cholesterol uptake. This review is focused on the novelty of CD based materials for NPC treatment.

Application of N-palmitoyl-O-phosphocholineserine for diagnosis and assessment of response to treatment in Niemann-Pick type C disease

Niemann-Pick type C (NPC) disease is a rare lysosomal storage disorder caused by mutations in either the NPC1 or the NPC2 gene. A new class of lipids, N-acyl-O-phosphocholineserines were recently identified as NPC biomarkers. The most abundant species in this class of lipid, N-palmitoyl-O-phosphocholineserine (PPCS), was evaluated for diagnosis of NPC disease and treatment efficacy assessment with 2-hydroxypropyl-β-cyclodextrin (HPβCD) in NPC. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were developed and validated to measure PPCS in human plasma and cerebrospinal fluid (CSF). A cutoff of 248 ng/mL in plasma provided a sensitivity of 100.0% and specificity of 96.6% in identifying NPC1 patients from control and NPC1 carrier subjects. PPCS was significantly elevated in CSF from NPC1 patients, and CSF PPCS levels were significantly correlated with NPC neurological disease severity scores. Plasma and CSF PPCS did not change significantly in response to intrathetical (IT) HPβCD treatment. In an intravenous (IV) HPβCD trial, plasma PPCS in all patients was significantly reduced. These results demonstrate that plasma PPCS was able to diagnose NPC1 patients with high sensitivity and specificity, and to evaluate the peripheral treatment efficacy of IV HPβCD treatment.

Intrathecal drug delivery in the era of nanomedicine

Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.

Expanded access with intravenous hydroxypropyl-β-cyclodextrin to treat children and young adults with Niemann-Pick disease type C1: a case report analysis

Background

Niemann-Pick Disease Type C (NPC) is an inherited, often fatal neurovisceral lysosomal storage disease characterized by cholesterol accumulation in every cell with few known treatments. Defects in cholesterol transport cause sequestration of unesterified cholesterol within the endolysosomal system. The discovery that systemic administration of hydroxypropyl-beta cyclodextrin (HPβPD) to NPC mice could release trapped cholesterol from lysosomes, normalize cholesterol levels in the liver, and prolong life, led to expanded access use in NPC patients. HPβCD has been administered to NPC patients with approved INDs globally since 2009.

Results

Here we present safety, tolerability and efficacy data from 12 patients treated intravenously (IV) for over 7 years with HPβCD in the US and Brazil. Some patients subsequently received intrathecal (IT) treatment with HPβCD following on average 13 months of IV HPβCD. Several patients transitioned to an alternate HPβCD. Moderately affected NPC patients treated with HPβCD showed slowing of disease progression. Severely affected patients demonstrated periods of stability but eventually showed progression of disease. Neurologic and neurocognitive benefits were seen in most patients with IV alone, independent of the addition of IT administration. Physicians and caregivers reported improvements in quality of life for the patients on IV therapy. There were no safety issues, and the drug was well tolerated and easy to administer.

Conclusions

These expanded access data support the safety and potential benefit of systemic IV administration of HPβCD and provide a platform for two clinical trials to study the effect of intravenous administration of HPβCD in NPC patients.

2-Hydroxypropyl-β-cyclodextrins and the Blood-Brain Barrier: Considerations for Niemann-Pick Disease Type C1

The rare, chronic, autosomal-recessive lysosomal storage disease Niemann-Pick disease type C1 (NPC1) is characterized by progressively debilitating and ultimately fatal neurological manifestations. There is an urgent need for disease-modifying therapies that address NPC1 neurological pathophysiology, and passage through the blood-brain barrier represents an important consideration for novel NPC1 drugs. Animal investigations of 2-hydroxypropyl-β-cyclodextrins (HPβCD) in NPC1 in mice demonstrated that HPβCD does not cross the blood-brain barrier in significant amounts but suggested a potential for these complex oligosaccharides to moderately impact CNS manifestations when administered subcutaneously or intraperitoneally at very high doses; however, safety concerns regarding pulmonary toxicity were raised. Subsequent NPC1 investigations in cats demonstrated far greater HPβCD efficacy at much lower doses when the drug was administered directly to the CNS. Based on this, a phase 1/2a clinical trial was initiated with intrathecal administration of a specific, wellcharacterized mixture of HPβCD, with a tightly controlled molar substitution specification and a defined molecular "fingerprint" of the different species. The findings were very encouraging and a phase 2b/3 clinical trial has completed enrollment and is underway. In addition, phase 1 clinical studies utilizing high-dose intravenous administration of a different HPβCD are currently recruiting. Independent studies are needed for each product to satisfactorily address questions of safety, efficacy, dosing, and route of administration. The outcomes cannot be assumed to be translatable between HPβCD products and/or routes of administration.

N-acyl-O-phosphocholineserines: structures of a novel class of lipids that are biomarkers for Niemann-Pick C1 disease

Niemann-Pick disease type C1 (NPC1) is a fatal, neurodegenerative, cholesterol storage disorder. With new therapeutics in clinical trials, there is an urgency to improve diagnostics and monitor therapeutic efficacy with biomarkers. In this study, we sought to define the structure of an unknown lipid biomarker for NPC1 with [M + H]⁺ ion at m/z 509.3351, previously designated as lysoSM-509. The structure of N-palmitoyl-O-phosphocholineserine (PPCS) was proposed for the lipid biomarker based on the results from mass spectrometric analyses and chemical derivatizations. As no commercial standard is available, authentic PPCS was chemically synthesized, and the structure was confirmed by comparison of endogenous and synthetic compounds as well as their derivatives using liquid chromatography-tandem mass spectrometry (LC-MS/MS). PPCS is the most abundant species among N-acyl-O-phosphocholineserines (APCS), a class of lipids that have not been previously detected in biological samples. Further analysis demonstrated that all APCS species with acyl groups ranging from C14 to C24 were elevated in NPC1 plasma. PPCS is also elevated in both central and peripheral tissues of the NPC1 cat model. Identification of APCS structures provide an opportunity for broader exploration of the roles of these novel lipids in NPC1 disease pathology and diagnosis.

Characterization of the Subventricular-Thalamo-Cortical Circuit in the NP-C Mouse Brain, and New Insights Regarding Treatment

Gliosis in Niemann-Pick type C (NP-C) disease is characterized by marked changes in microglia and astrocytes. However, the gliosis onset and progression in NP-C has not been systematically studied, nor has the mechanism underlying this finding. Here, we found early gliosis in the subventricular zone (SVZ) of NP-C mice. Neural progenitor damage by Npc1 mutation suppressed vascular endothelial growth factor (VEGF) expression and further induced microglia activation followed by astrogliosis. Interestingly, excessive astrogliosis in the SVZ induced neural progenitor retention and/or migration into thalamus via astrocyte-derived VEGF, resulting in acceleration of thalamic and cortical gliosis through thalamo-cortical pathways. Transplantation of VEGF-overexpressing neural stem cells into the SVZ improved whole-brain pathology of NP-C mice. Overall, our data provide a new pathological perspective on NP-C neural pathology, revealing abnormalities in the subventricular-thalamo-cortical circuit of NP-C mouse brain and highlighting the importance of the SVZ microenvironment as a therapeutic target for NP-C disease.

The complexity of a monogenic neurodegenerative disease: More than two decades of therapeutic driven research into Niemann-Pick type C disease

Niemann-Pick type C (NP-C) disease is a rare and fatal neurodegenerative disease typified by aberrations in intracellular lipid transport. Cholesterol and other lipids accumulate in the late endosome/lysosome of all diseased cells thereby causing neuronal and visceral atrophy. A cure for NP-C remains elusive despite the extensive molecular advances emanating from the identification of the primary genetic defect in 1997. Penetration of the blood-brain barrier and efficacy in the viscera are prerequisites for effective therapy, however the rarity of NP-C disease is the major impediment to progress. Disease diagnosis is challenging and establishment of appropriate test populations for clinical trials difficult. Fortunately, disease models that span the diversity of microbial and metazoan life have been utilized to advance the quest for a therapy. The complexity of lipid storage in this disorder and in the model systems, has led to multiple theories on the primary disease mechanism and consequently numerous and varied proposed interventions. Here, we conduct an evaluation of these studies.

Synthesis of the Anionic Hydroxypropyl-β-cyclodextrin:Poly(decamethylenephosphate) Polyrotaxane and Evaluation of its Cholesterol Efflux Potential in Niemann-Pick C1 Cells

Niemann-Pick type C disease (NPC) is a lysosomal storage disease that is characterized by a progressive accumulation of unesterified cholesterol in the lysosomes leading to organ damage from cell dysfunction. Hydroxypropyl-β-cyclodextrin (HP-β-CD) is an attractive drug candidate for treating NPC, as it diminishes cholesterol accumulation in NPC cells. Systemic HP-β-CD treatment, however, is limited by rapid renal clearance. We designed a new anionic HP-β-CD polyrotaxane to act as a slow release formulation based on a polyalkylene phosphate core to improve the pharmacokinetics. The polyalkylene phosphate comprises hydrophobic decamethylene spacers linked by biodegradable anionic phosphodiester bonds. HP-β-CD was threaded onto this polymer first and α-CD afterwards to prevent burst release of the threaded HP-β-CD. Our findings show that HP-β-CD was slowly released from the watersoluble polyrotaxane over a 30 days period. The polyrotaxane provided persistently diminished cholesterol levels in NPC1 cells by 20% relative to untreated cells. These results demonstrate the therapeutic potential of this novel HP-β-CD polyrotaxane for the mobilization of aberrantly stored cholesterol in NPC1 cells.

Hydroxypropyl-beta and -gamma cyclodextrins rescue cholesterol accumulation in Niemann-Pick C1 mutant cell via lysosome-associated membrane protein 1

Niemann-Pick type C (NPC) disease is a fatal hereditary neurodegenerative disorder characterized by a massive accumulation of cholesterol in lysosomes and late endosomes due to a defect in intracellular cholesterol trafficking. Dysfunction in intracellular cholesterol trafficking is responsible for about 50 rare inherited lysosomal storage disorders including NPC. The lysosomal proteins NPC1 and NPC2 play a crucial role in trafficking of cholesterol from late endosomes and lysosomes to other cellular compartments. However, the detailed mechanisms of cholesterol trafficking at the late endosomes/lysosomes (LE/LY) are poorly understood. Studies showed that 2-hydroxypropyl-β-cyclodextrin (HPβCD) alleviates the cholesterol accumulation defect in animal model and has been approved for a phase 2b/3 clinical trial for NPC. HPβCD is known to bind cholesterol; however, the mechanisms how HPβCD mediates the exit of cholesterol from the LE/LY compartments are still unknown. Further, another cyclodextrin (CD) derivative, 2-hydroxypropyl-γ-cyclodextrin (HPγCD), was shown to reduce intracellular cholesterol accumulation in NPC patient cells and NPC mice model. Herein, we identified a number of candidate proteins differentially expressed in NPC patient-derived cells compared to cells derived from a healthy donor using a proteomic approach. Interestingly, both HPβCD and HPγCD treatments modulated the expression of most of these NPC-specific proteins. Data showed that treatment with both CDs induces the expression of the lysosome-associated membrane protein 1 (LAMP-1) in NPC patient-derived cells. Remarkably, LAMP-1 overexpression in HeLa cells rescued U18666A-induced cholesterol accumulation suggesting a role of LAMP-1 in cholesterol trafficking. We propose that HPβCD and HPγCD facilitate cholesterol export from the LE/LY compartments via the LAMP-1 protein, which may play a crucial role in cholesterol trafficking at the LE/LY compartments when there is no functional NPC1 protein. Together, this study uncovers new cellular mechanisms for cholesterol trafficking, which will contribute to development of novel therapeutic approaches for lysosomal storage diseases.

Olfactory Performance as an Indicator for Protective Treatment Effects in an Animal Model of Neurodegeneration

Background: Neurodegenerative diseases are often accompanied by olfactory deficits. Here we use a rare neurovisceral lipid storage disorder, Niemann–Pick disease C1 (NPC1), to illustrate disease-specific dynamics of olfactory dysfunction and its reaction upon therapy. Previous findings in a transgenic mouse model (NPC1^-/-) showed severe morphological and electrophysiological alterations of the olfactory epithelium (OE) and the olfactory bulb (OB) that ameliorated under therapy with combined 2-hydroxypropyl-ß-cyclodextrin (HPßCD)/allopregnanolone/miglustat or HPßCD alone.

Methods: A buried pellet test was conducted to assess olfactory performance. qPCR for olfactory key markers and several olfactory receptors was applied to determine if their expression was changed under treatment conditions. In order to investigate the cell dynamics of the OB, we determined proliferative and apoptotic activities using a bromodeoxyuridine (BrdU) protocol and caspase-3 (cas-3) activity. Further, we performed immunohistochemistry and western blotting for microglia (Iba1), astroglia (GFAP) and tyrosine hydroxylase (TH).

Results: The buried pellet test revealed a significant olfactory deterioration in NPC1^-/- mice, which reverted to normal levels after treatment. At the OE level, mRNA for olfactory markers showed no changes; the mRNA level of classical olfactory receptor (ORs) was unaltered, that of unique ORs was reduced. In the OB of untreated NPC1^-/- mice, BrdU and cas-3 data showed increased proliferation and apoptotic activity, respectively. At the protein level, Iba1 and GFAP in the OB indicated increased microgliosis and astrogliosis, which was prevented by treatment.

Conclusion: Due to the unique plasticity especially of peripheral olfactory components the results show a successful treatment in NPC1 condition with respect to normalization of olfaction. Unchanged mRNA levels for olfactory marker protein and distinct olfactory receptors indicate no effects in the OE in NPC1^-/- mice. Olfactory deficits are thus likely due to central deficits at the level of the OB. Further studies are needed to examine if olfactory performance can also be changed at a later onset and interrupted treatment of the disease. Taken together, our results demonstrate that olfactory testing in patients with NPC1 may be successfully used as a biomarker during the monitoring of the treatment.

BACE1-cleavage of Sez6 and Sez6L is elevated in Niemann-Pick type C disease mouse brains

It is intriguing that a rare, inherited lysosomal storage disorder Niemann-Pick type C (NPC) shares similarities with Alzheimer’s disease (AD). We have previously reported an enhanced processing of β-amyloid precursor protein (APP) by β-secretase (BACE1), a key enzyme in the pathogenesis of AD, in NPC1-null cells. In this work, we characterized regional and temporal expression and processing of the recently identified BACE1 substrates seizure protein 6 (Sez6) and seizure 6-like protein (Sez6L), and APP, in NPC1^-/- (NPC1) and NPC1^+/+ (wt) mouse brains. We analysed 4-weeks old brains to detect the earliest changes associated with NPC, and 10-weeks of age to identify changes at terminal disease stage. Sez6 and Sez6L were selected due to their predominant cleavage by BACE1, and their potential role in synaptic function that may contribute to presentation of seizures and/or motor impairments in NPC patients. While an enhanced BACE1-cleavage of all three substrates was detected in NPC1 vs. wt-mouse brains at 4-weeks of age, at 10-weeks increased proteolysis by BACE1 was observed for Sez6L in the cortex, hippocampus and cerebellum of NPC1-mice. Interestingly, both APP and Sez6L were found to be expressed in Purkinje neurons and their immunostaining was lost upon Purkinje cell neurodegeneration in 10-weeks old NPC1 mice. Furthermore, in NPC1- vs. wt-mouse primary cortical neurons, both Sez6 and Sez6L showed increased punctuate staining within the endolysosomal pathway as well as increased Sez6L and BACE1-positive puncta. This indicates that a trafficking defect within the endolysosomal pathway may play a key role in enhanced BACE1-proteolysis in NPC disease. Overall, our findings suggest that enhanced proteolysis by BACE1 could be a part of NPC disease pathogenesis. Understanding the basic biology of BACE1 and the functional impact of cleavage of its substrates is important to better evaluate the therapeutic potential of BACE1 against AD and, possibly, NPC disease.

Complex polymorphisms in endocytosis genes suggest alpha-cyclodextrin as a treatment for breast cancer

Most breast cancer deaths are caused by metastasis and treatment options beyond radiation and cytotoxic drugs, which have severe side effects, and hormonal treatments, which are or become ineffective for many patients, are urgently needed. This study reanalyzed existing data from three genome-wide association studies (GWAS) using a novel computational biostatistics approach (muGWAS), which had been validated in studies of 600-2000 subjects in epilepsy and autism. MuGWAS jointly analyzes several neighboring single nucleotide polymorphisms while incorporating knowledge about genetics of heritable diseases into the statistical method and about GWAS into the rules for determining adaptive genome-wide significance. Results from three independent GWAS of 1000-2000 subjects each, which were made available under the National Institute of Health's "Up For A Challenge" (U4C) project, not only confirmed cell-cycle control and receptor/AKT signaling, but, for the first time in breast cancer GWAS, also consistently identified many genes involved in endo-/exocytosis (EEC), most of which had already been observed in functional and expression studies of breast cancer. In particular, the findings include genes that translocate (ATP8A1, ATP8B1, ANO4, ABCA1) and metabolize (AGPAT3, AGPAT4, DGKQ, LPPR1) phospholipids entering the phosphatidylinositol cycle, which controls EEC. These novel findings suggest scavenging phospholipids as a novel intervention to control local spread of cancer, packaging of exosomes (which prepare distant microenvironment for organ-specific metastases), and endocytosis of β1 integrins (which are required for spread of metastatic phenotype and mesenchymal migration of tumor cells). Beta-cyclodextrins (βCD) have already been shown to be effective in in vitro and animal studies of breast cancer, but exhibits cholesterol-related ototoxicity. The smaller alpha-cyclodextrins (αCD) also scavenges phospholipids, but cannot fit cholesterol. An in-vitro study presented here confirms hydroxypropyl (HP)-αCD to be twice as effective as HPβCD against migration of human cells of both receptor negative and estrogen-receptor positive breast cancer. If the previous successful animal studies with βCDs are replicated with the safer and more effective αCDs, clinical trials of adjuvant treatment with αCDs are warranted. Ultimately, all breast cancer are expected to benefit from treatment with HPαCD, but women with triple-negative breast cancer (TNBC) will benefit most, because they have fewer treatment options and their cancer advances more aggressively.

Linear Cyclodextrin Polymer Prodrugs as Novel Therapeutics for Niemann-Pick Type C1 Disorder

Niemann-Pick Type C1 disorder (NPC) is a rare lysosomal storage disease characterized by the accumulation of cholesterol in lysosomes. NPC has no FDA approved treatments yet, however 2-hydroxypropyl-β-cyclodextrin (HPβCD) has shown efficacy for treating the disease in both mouse and feline NPC models and is currently being investigated in late stage clinical trials. Despite promising results, therapeutic use of HPβCD is limited by the need for high doses, ototoxicity and intrathecal administration. These limitations can be attributed to its poor pharmacokinetic profile. In the attempt to overcome these limitations, we have designed a β-cyclodextrin (βCD) based polymer prodrugs (ORX-301) for an enhanced pharmacokinetic and biodistribution profile, which in turn can potentially provide an improved efficacy at lower doses. We demonstrated that subcutaneously injected ORX-301 extended the mean lifespan of NPC mice at a dosage 5-fold lower (800 mg/kg, body weight) the HPβCD dose proven efficacious (4000 mg/kg). We also show that ORX-301 penetrates the blood brain barrier and counteracts neurological impairment. These properties represent a substantial improvement and appear to overcome major limitations of presently available βCD-based therapy, demonstrating that this novel prodrug is a valuable alternative/complement for existing therapies.

Communication pathways to and from the inner ear and their contributions to drug delivery

The environment of the inner ear is highly regulated in a manner that some solutes are permitted to enter while others are excluded or transported out. Drug therapies targeting the sensory and supporting cells of the auditory and vestibular systems require the agent to gain entry to the fluid spaces of the inner ear, perilymph or endolymph, which surround the sensory organs. Access to the inner ear fluids from the vasculature is limited by the blood-labyrinth barriers, which include the blood-perilymph and blood-strial barriers. Intratympanic applications provide an alternative approach in which drugs are applied locally. Drug from the applied solution enters perilymph through the round window membrane, through the stapes, and under some circumstances, through thin bone in the otic capsule. The amount of drug applied to the middle ear is always substantially more than the amount entering perilymph. As a result, significant amounts of the applied drug can pass to the digestive system, to the vasculature, and to the brain. Drugs in perilymph pass to the vasculature and to cerebrospinal fluid via the cochlear aqueduct. Conversely, drugs applied to cerebrospinal fluid, including those given intrathecally, can enter perilymph through the cochlear aqueduct. Other possible routes in or out of the ear include passage by neuronal pathways, passage via endolymph and the endolymphatic sac, and possibly via lymphatic pathways. A better understanding of the pathways for drug movements in and out of the ear will enable better intervention strategies.

Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules

Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

Pharmacokinetic principles in the inner ear: Influence of drug properties on intratympanic applications

Local drug delivery to the ear has gained wide clinical acceptance, with the choice of drug and application protocol in humans largely empirically-derived. Here, we review the pharmacokinetics underlying local therapy of the ear using the drugs commonly used in clinical practice as examples. Based on molecular properties and perilymph measurements interpreted through computer simulations we now better understand the principles underlying entry and distribution of these and other drugs in the ear. From our analysis, we have determined that dexamethasone-phosphate, a pro-drug widely-used clinically, has molecular and pharmacokinetic properties that make it ill-suited for use as a local therapy for hearing disorders. This polar form of dexamethasone, used as a more soluble agent in intravenous preparations, passes less readily through lipid membranes, such as those of the epithelia restricting entry at the round window membrane and stapes. Once within the inner ear, dexamethasone-phosphate is cleaved to the active form, dexamethasone, which is less polar, passes more readily through lipid membranes of the blood-perilymph barrier and is rapidly eliminated from perilymph without distributing to apical cochlear regions. Dexamethasone-phosphate therefore provides only a brief exposure of the basal regions of the cochlea to active drug. Other steroids, such as triamcinolone-acetonide, exhibit pharmacokinetic properties more appropriate to the ear and merit more detailed consideration.

Long-Term Treatment of Niemann-Pick Type C1 Disease With Intrathecal 2-Hydroxypropyl-β-Cyclodextrin

BACKGROUND

Intrathecal 2-hydoxypropyl-β-cyclodextrin has been found to mobilize cholesterol, extend life, reduce cerebellar pathology, and delay onset of ataxia in the mouse and cat models of Niemann-Pick disease, type C1, a clinically variable progressive and ultimately fatal neurodegenerative storage disorder characterized by endolysosomal accumulation of unesterified cholesterol.

OBJECTIVE

In this study, the long-term effects of intrathecal 2-hydoxypropyl-β-cyclodextrin treatment for 2.5 to three years in humans with Niemann-Pick disease, type C, were evaluated.

METHODS

Three patients with Niemann-Pick disease, type C, in different stages of progression and displaying varying disease manifestations were treated with intrathecal 2-hydoxypropyl-β-cyclodextrin (VTS-270) delivered by lumbar puncture infusion through an intermediate-size patient population investigational new drug application for expanded access. Disease progression was monitored with the Niemann-Pick disease, type C, Neurological Severity Scale and numerous objective measures of function in five neurological domains typically impacted by the disease: cognitive/language, gait/balance, fine motor, swallowing, and eye movement.

RESULTS

No worsening in any domain except eye movements (vertical pursuit gain) was seen for any of the three patients, and in the other domains, improved scores on measures were seen over time for one or more patients. The Niemann-Pick disease type C (NPC) Neurological Severity Scale (NSS) showed stable to slightly improved ratings.

CONCLUSIONS

These trajectories are not consistent with the typical trajectory of the disease and suggest that intrathecal 2-hydoxypropyl-β-cyclodextrin has stabilized the disease over an extended period of time, supporting the current phase 2/3 controlled registration trial with VTS-270.

Polyrotaxane-based systemic delivery of β-cyclodextrins for potentiating therapeutic efficacy in a mouse model of Niemann-Pick type C disease

Niemann-Pick type C (NPC) disease is a fatal metabolic disorder characterized by the lysosomal accumulation of cholesterol. Although 2-hydroxypropyl β-cyclodextrin (HP-β-CD) promotes the excretion of cholesterol and prolongs the life span in animal models of NPC disease, it requires extremely high dose. We developed acid-labile β-CD-based polyrotaxanes (PRXs) comprising multiple β-CDs threaded along a polymer chain capped with acid-cleavable stopper molecules for potentiating therapeutic efficacy of β-CD in NPC disease. The acid-labile PRXs dissociate under the acidic lysosomes and release threaded β-CDs in lysosomes, which promotes cholesterol excretion in NPC disease model cells at lower concentration than HP-β-CD. In this study, the therapeutic effect of the PRXs in a mouse model of NPC disease was investigated. Weekly administration of the PRXs significantly prolonged the life span and suppressed neurodegeneration in mice, even at a dose of 500mg/kg, a markedly lower dose than previously reported for HP-β-CD. Detailed analysis of tissue cholesterol revealed that PRX treatment markedly suppressed the tissue accumulation of cholesterol in the NPC mouse model, but did not alter cholesterol content in wild-type mice. Acid-labile PRX is therefore a promising candidate for potentiating the efficacy of β-CD in the treatment of NPC disease.

Cyclodextrins and Iatrogenic Hearing Loss: New Drugs with Significant Risk

Cyclodextrins are a family of cyclic oligosaccharides with widespread usage in medicine, industry and basic sciences owing to their ability to solubilize and stabilize guest compounds. In medicine, cyclodextrins primarily act as a complexing vehicle and consequently serve as powerful drug delivery agents. Recently, uncomplexed cyclodextrins have emerged as potent therapeutic compounds in their own right, based on their ability to sequester and mobilize cellular lipids. In particular, 2-hydroxypropyl-β-cyclodextrin (HPβCD) has garnered attention because of its cholesterol chelating properties, which appear to treat a rare neurodegenerative disorder and to promote atherosclerosis regression related to stroke and heart disease. Despite the potential health benefits, use of HPβCD has been linked to significant hearing loss in several species, including humans. Evidence in mice supports a rapid onset of hearing loss that is dose-dependent. Ototoxicity can occur following central or peripheral drug delivery, with either route resulting in the preferential loss of cochlear outer hair cells (OHCs) within hours of dosing. Inner hair cells and spiral ganglion cells are spared at doses that cause ~85% OHC loss; additionally, no other major organ systems appear adversely affected. Evidence from a first-to-human phase 1 clinical trial mirrors animal studies to a large extent, indicating rapid onset and involvement of OHCs. All patients in the trial experienced some permanent hearing loss, although a temporary loss of function can be observed acutely following drug delivery. The long-term impact of HPβCD use as a maintenance drug, and the mechanism(s) of ototoxicity, are unknown. β-cyclodextrins preferentially target membrane cholesterol, but other lipid species and proteins may be directly or indirectly involved. Moreover, as cholesterol is ubiquitous in cell membranes, it remains unclear why OHCs are preferentially susceptible to HPβCD. It is possible that HPβCD acts upon several targets—for example, ion channels, tight junctions (TJ), membrane integrity, and bioenergetics—that collectively increase the sensitivity of OHCs over other cell types.

Intrathecal 2-hydroxypropyl-β-cyclodextrin decreases neurological disease progression in Niemann-Pick disease, type C1: a non-randomised, open-label, phase 1-2 trial

BACKGROUND

Niemann-Pick disease, type C1 (NPC1) is a lysosomal storage disorder characterised by progressive neurodegeneration. In preclinical testing, 2-hydroxypropyl-β-cyclodextrins (HPβCD) significantly delayed cerebellar Purkinje cell loss, slowed progression of neurological manifestations, and increased lifespan in mouse and cat models of NPC1. The aim of this study was to assess the safety and efficacy of lumbar intrathecal HPβCD.

METHODS

In this open-label, dose-escalation phase 1-2a study, we gave monthly intrathecal HPβCD to participants with NPC1 with neurological manifestation at the National Institutes of Health (NIH), Bethesda, MD, USA. To explore the potential effect of 2-week dosing, three additional participants were enrolled in a parallel study at Rush University Medical Center (RUMC), Chicago, IL, USA. Participants from the NIH were non-randomly, sequentially assigned in cohorts of three to receive monthly initial intrathecal HPβCD at doses of 50, 200, 300, or 400 mg per month. A fifth cohort of two participants received initial doses of 900 mg. Participants from RUMC initially received 200 or 400 mg every 2 weeks. The dose was escalated based on tolerance or safety data from higher dose cohorts. Serum and CSF 24(S)-hydroxycholesterol (24[S]-HC), which serves as a biomarker of target engagement, and CSF protein biomarkers were evaluated. NPC Neurological Severity Scores (NNSS) were used to compare disease progression in HPβCD-treated participants relative to a historical comparison cohort of 21 NPC1 participants of similar age range.

FINDINGS

Between Sept 21, 2013, and Jan 19, 2015, 32 participants with NPC1 were assessed for eligibility at the National Institutes of Health. 18 patients were excluded due to inclusion criteria not met (six patients), declined to participate (three patients), pursued independent expanded access and obtained the drug outside of the study (three patients), enrolled in the RUMC cohort (one patient), or too late for the trial enrolment (five patients). 14 patients were enrolled and sequentially assigned to receive intrathecal HPβCD at a starting dose of 50 mg per month (three patients), 200 mg per month (three patients), 300 mg per month (three patients), 400 mg per month (three patients), or 900 mg per month (two patients). During the first year, two patients had treatment interrupted for one dose, based on grade 1 ototoxicity. All 14 patients were assessed at 12 months. Between 12 and 18 months, one participant had treatment interrupted at 17 months due to hepatocellular carcinoma, one patient had dose interruption for 2 doses based on caregiver hardship and one patient had treatment interrupted for 1 dose for mastoiditis. 11 patients were assessed at 18 months. Between Dec 11, 2013, and June 25, 2014, three participants were assessed for eligibility and enrolled at RUMC, and were assigned to receive intrathecal HPβCD at a starting dose of 200 mg every 2 weeks (two patients), or 400 mg every two weeks (one patient). There were no dropouts in this group and all 3 patients were assessed at 18 months. Biomarker studies were consistent with improved neuronal cholesterol homoeostasis and decreased neuronal pathology. Post-drug plasma 24(S)-HC area under the curve (AUC8-72) values, an indicator of neuronal cholesterol homoeostasis, were significantly higher than post-saline plasma 24(S)-HC AUC8-72 after doses of 900 mg (p=0·0063) and 1200 mg (p=0·0037). CSF 24(S)-HC concentrations in three participants given either 600 or 900 mg of HPβCD were increased about two fold (p=0·0032) after drug administration. No drug-related serious adverse events were observed. Mid-frequency to high-frequency hearing loss, an expected adverse event, was documented in all participants. When managed with hearing aids, this did not have an appreciable effect on daily communication. The NNSS for the 14 participants treated monthly increased at a rate of 1·22, SEM 0·34 points per year compared with 2·92, SEM 0·27 points per year (p=0·0002) for the 21 patient comparison group. Decreased progression was observed for NNSS domains of ambulation (p=0·0622), cognition (p=0·0040) and speech (p=0·0423).

INTERPRETATION

Patients with NPC1 treated with intrathecal HPβCD had slowed disease progression with an acceptable safety profile. These data support the initiation of a multinational, randomised, controlled trial of intrathecal HPβCD.

FUNDING

National Institutes of Health, Dana's Angels Research Trust, Ara Parseghian Medical Research Foundation, Hope for Haley, Samantha's Search for the Cure Foundation, National Niemann-Pick Disease Foundation, Support of Accelerated Research for NPC Disease, Vtesse, Janssen Research and Development, a Johnson & Johnson company, and Johnson & Johnson.

Is 2-Hydroxypropyl-β-cyclodextrin a Suitable Carrier for Central Administration of Δ9 -Tetrahydrocannabinol? Preclinical Evidence

Preclinical Research Δ⁹ -Tetrahydrocannabinol (THC) is a hydrophobic compound that has a potent antinociceptive effect in animals after intrathecal (IT) or intracerebroventricular (ICV) administration. The lack of a suitable solvent precludes its IT administration in humans. 2-Hydroxypropyl-β-cyclodextrin (HPβCD) increases the water solubility of hydrophobic drugs and is approved for IT administration in humans. To investigate whether HPβCD might be a suitable carrier for ICV administration of THC in rats, two formulations containing THC complexed with HPβCD (30 and 135 μg of THC per animal) and vehicle were administered to Wistar rats. The antinociceptive effect (using the tail flick test), locomotor activity, and body temperature were evaluated. ICV injection of 135 μg of THC/HPβCD complex increased tail flick latency, reduced locomotor activity, and had a dual effect on body temperature. The 30 μg THC/HPβCD formulation only produced a hyperthermic effect. All animals appeared healthy, with no difference between the groups. These results were similar to those obtained in other preclinical studies in which THC was administered centrally using solvents that are unsuitable for IT administration in humans because of their toxicity. Our findings suggest that HPβCD may be a useful carrier for IT administration of THC in humans. Drug Dev Res 78 : 411-419, 2017. © 2017 Wiley Periodicals, Inc.

Methyl-β-cyclodextrin restores impaired autophagy flux in Niemann-Pick C1-deficient cells through activation of AMPK

The drug 2-hydroxypropyl-β-cyclodextrin (HPβCD) reduces lysosomal cholesterol accumulation in Niemann-Pick disease, type C (NPC) and has been advanced to human clinical trials. However, its mechanism of action for reducing cholesterol accumulation in NPC cells is uncertain and its molecular target is unknown. We found that methyl-β-cyclodextrin (MβCD), a potent analog of HPβCD, restored impaired macroautophagy/autophagy flux in Niemann-Pick disease, type C1 (NPC1) cells. This effect was mediated by a direct activation of AMP-activated protein kinase (AMPK), an upstream kinase in the autophagy pathway, through MβCD binding to its β-subunits. Knockdown of PRKAB1 or PRKAB2 (encoding the AMPK β1 or β2 subunit) expression and an AMPK inhibitor abolished MβCD-mediated reduction of cholesterol storage in NPC1 cells. The results demonstrate that AMPK is the molecular target of MβCD and its activation enhances autophagy flux, thereby mitigating cholesterol accumulation in NPC1 cells. The results identify AMPK as an attractive target for drug development to treat NPC.

Cyclodextrin has conflicting actions on autophagy flux in vivo in brains of normal and Alzheimer model mice

2-hydroxypropyl-β-cyclodextrin (CYCLO), a modifier of cholesterol efflux from cellular membrane and endo-lysosomal compartments, reduces lysosomal lipid accumulations and has therapeutic effects in animal models of Niemann-Pick disease type C and several other neurodegenerative states. Here, we investigated CYCLO effects on autophagy in wild-type mice and TgCRND8 mice-an Alzheimer's Disease (AD) model exhibiting β-amyloidosis, neuronal autophagy deficits leading to protein and lipid accumulation within greatly enlarged autolysosomes. A 14-day intracerebroventricular administration of CYCLO to 8-month-old TgCRND8 mice that exhibit moderately advanced neuropathology markedly diminished the sizes of enlarged autolysosomes and lowered their content of GM2 ganglioside and Aβ-immunoreactivity without detectably altering amyloid precursor protein processing or extracellular Aβ/β-amyloid burden. We identified two major actions of CYCLO on autophagy underlying amelioration of lysosomal pathology. First, CYCLO stimulated lysosomal proteolytic activity by increasing cathepsin D activity, levels of cathepsins B and D and two proteins known to interact with cathepsin D, NPC1 and ABCA1. Second, CYCLO impeded autophagosome-lysosome fusion as evidenced by the accumulation of LC3, SQSTM1/p62, and ubiquitinated substrates in an expanded population of autophagosomes in the absence of greater autophagy induction. By slowing substrate delivery to lysosomes, autophagosome maturational delay, as further confirmed by our in vitro studies, may relieve lysosomal stress due to accumulated substrates. These findings provide in vivo evidence for lysosomal enhancing properties of CYCLO, but caution that prolonged interference with cellular membrane fusion/autophagosome maturation could have unfavorable consequences, which might require careful optimization of dosage and dosing schedules.

Potential Use of Cyclodextrins as Drug Carriers and Active Pharmaceutical Ingredients

Cyclodextrins (CyDs) are extensively used in various fields, and especially have been widely utilized as pharmaceutical excipients and drug carriers in the pharmaceutical field. Owing to the multi-functional and biocompatible characteristics, CyDs can improve the undesirable properties of drug molecules. This review outlines the current application of CyDs in pharmaceutical formulations, focusing on their use as CyD-based drug carriers for several kinds of drugs. Additionally, CyDs have great potential as active pharmaceutical ingredients against various diseases with few side effects.

Increased Regenerative Capacity of the Olfactory Epithelium in Niemann-Pick Disease Type C1

Niemann–Pick disease type C1 (NPC1) is a fatal neurovisceral lysosomal lipid storage disorder. The mutation of the NPC1 protein affects the homeostasis and transport of cholesterol and glycosphingolipids from late endosomes/lysosomes to the endoplasmic reticulum resulting in progressive neurodegeneration. Since olfactory impairment is one of the earliest symptoms in many neurodegenerative disorders, we focused on alterations of the olfactory epithelium in an NPC1 mouse model. Previous findings revealed severe morphological and immunohistochemical alterations in the olfactory system of NPC1^−/− mutant mice compared with healthy controls (NPC1^+/+). Based on immunohistochemical evaluation of the olfactory epithelium, we analyzed the impact of neurodegeneration in the olfactory epithelium of NPC1^−/− mice and observed considerable loss of mature olfactory receptor neurons as well as an increased number of proliferating and apoptotic cells. Additionally, after administration of two different therapy approaches using either a combination of miglustat, 2-hydroxypropyl-β-cyclodextrin (HPβCD) and allopregnanolone or a monotherapy with HPβCD, we recorded a remarkable reduction of morphological damages in NPC1^−/− mice and an up to four-fold increase of proliferating cells within the olfactory epithelium. Numbers of mature olfactory receptor neurons doubled after both therapy approaches. Interestingly, we also observed therapy-induced alterations in treated NPC1^+/+ controls. Thus, olfactory testing may provide useful information to monitor pharmacologic treatment approaches in human NPC1.

Characterization of cholesterol homeostasis in sphingosine-1-phosphate lyase-deficient fibroblasts reveals a Niemann-Pick disease type C-like phenotype with enhanced lysosomal Ca2+ storage

Sphingosine-1-phosphate (S1P) lyase irreversibly cleaves S1P, thereby catalysing the ultimate step of sphingolipid degradation. We show here that embryonic fibroblasts from S1P lyase-deficient mice (Sgpl1^−/−-MEFs), in which S1P and sphingosine accumulate, have features of Niemann-Pick disease type C (NPC) cells. In the presence of serum, overall cholesterol content was elevated in Sgpl1^−/−-MEFs, due to upregulation of the LDL receptor and enhanced cholesterol uptake. Despite this, activation of sterol regulatory element-binding protein-2 was increased in Sgpl1^−/−-MEFs, indicating a local lack of cholesterol at the ER. Indeed, free cholesterol was retained in NPC1-containing vesicles, which is a hallmark of NPC. Furthermore, upregulation of amyloid precursor protein in Sgpl1^−/−-MEFs was mimicked by an NPC1 inhibitor in Sgpl1^+/+-MEFs and reduced by overexpression of NPC1. Lysosomal pH was not altered by S1P lyase deficiency, similar to NPC. Interestingly, lysosomal Ca²⁺ content and bafilomycin A1-induced [Ca²⁺]_i increases were enhanced in Sgpl1^−/−-MEFs, contrary to NPC. These results show that both a primary defect in cholesterol trafficking and S1P lyase deficiency cause overlapping phenotypic alterations, and challenge the present view on the role of sphingosine in lysosomal Ca²⁺ homeostasis.