Whole Body and CNS Biodistribution of rhHNS in Cynomolgus Monkeys after Intrathecal Lumbar Administration: Treatment Implications for Patients with MPS IIIA.

Mucopolysaccharidosis III type A (MPS IIIA; Sanfilippo syndrome), a genetic lysosomal disorder causing a deficiency of heparan N-sulfatase (HNS), leads to progressive cognitive decline from an early age. An effective enzyme replacement therapy (ERT) for MPS IIIA requires central nervous system (CNS) biodistribution. Recombinant human heparan N-sulfatase (rhHNS), an investigatory ERT for MPS IIIA, has been formulated for intrathecal (IT) administration since intravenous (IV) administration cannot cross the blood brain barrier (BBB) in sufficient amounts to have a therapeutic effect. In this study, systemic and CNS distribution of rhHNS in cynomolgus monkeys following IV and IT administration was evaluated by quantitation of rhHNS in serum, cerebral spinal fluid (CSF) and various tissues, and positron emission tomography (PET) imaging of live animals. Following IV administration, rhHNS levels were low to non-detectable in the CSF, and systemic clearance was rapid (≤2 h). With IT administration, rhHNS was observable in CNS tissues in ≤1 h, with varying Tmax (1-24 h). Appreciable systemic distribution was observed up to 7 days. This provides evidence that in this animal model, intrathecal administration of rhHNS delivers the replacement enzyme to therapeutically relevant tissues for the treatment of Sanfilippo Syndrome type A. Penetration into grey matter and cortex was 3-4 times greater than concentrations in white matter and deeper parenchymal regions, suggesting some limitations of this ERT strategy.

Online 2D-LC-MS/MS assay to quantify therapeutic protein in human serum in the presence of pre-existing antidrug antibodies.

The formation of antidrug antibodies (ADA) can interfere with the accurate quantitation of therapeutic proteins, leading to significantly underestimated drug concentrations and confounded pharmacokinetic (PK) data interpretation. Although highly desirable, development of ADA-tolerant bioanalytical methods enabling unbiased measurement of both free and ADA-bound drug presents a considerable challenge. We report herein the development and validation of a robust LC-MS assay capable of quantifying therapeutic protein immunoglobulin A1 protease (IgAP) in human serum in the presence of pre-existing anti-IgAP antibodies. The procedure included sodium dodecyl sulfate (SDS) denaturation and chemical reduction of serum proteins to dissociate ADA-drug bindings, followed by tryptic digestion of protein pellets and subsequent LC-MS analysis of the surrogate IgAP peptide using stable isotope labeled peptide internal standard. Substantial enhancements in the sensitivity and selectivity were achieved by the combination of online two-dimensional reversed-phase LC (2D-LC) operated in high and low pH buffers, respectively, for efficient enrichment and quantitation of the surrogate peptide by multiple-reaction monitoring (MRM) mass spectrometry. Unlike ligand-binding assay, our method is not prone to interferences from ADA, allowing accurate and precise measurement of the IgAP in the range of 0.05 to 10 µg/mL in 25 µL of human serum with a wide range of anti-IgAP antibody levels. The intra- and inter-run precision (coefficient of variation (CV%)) was within 11.5% and 10.5%, respectively, and the bias was within ±7.1% for all quality control (QC) concentrations. With little modification, the described method can readily be applicable to the quantitation of other biotherapeutic proteins in the ADA-positive clinical matrices.

Drugging the epigenome in the age of precision medicine.

BACKGROUND: Modulating the epigenome has long been considered a potential opportunity for therapeutic intervention in numerous disease areas with several approved therapies marketed, primarily for cancer. Despite the overall promise of early approaches, however, these drugs have been plagued by poor pharmacokinetic and safety/tolerability profiles due in large part to off-target effects and a lack of specificity. RESULTS: Recently, there has been marked progress in the field on a new generation of epigenomic therapies which address these challenges directly by targeting defined loci with highly precise, durable, and tunable approaches. Here, we review the promise and pitfalls of epigenetic drug development to date and provide an outlook on recent advances and their promise for future therapeutic applications. CONCLUSIONS: Novel therapeutic modalities leveraging epigenetics and epigenomics with increased precision are well positioned to advance the field and treat patients across disease areas in the coming years.

Comparing Bayesian Variable Selection to Lasso Approaches for Applications in Psychology.

In the current paper, we review existing tools for solving variable selection problems in psychology. Modern regularization methods such as lasso regression have recently been introduced in the field and are incorporated into popular methodologies, such as network analysis. However, several recognized limitations of lasso regularization may limit its suitability for psychological research. In this paper, we compare the properties of lasso approaches used for variable selection to Bayesian variable selection approaches. In particular we highlight advantages of stochastic search variable selection (SSVS), that make it well suited for variable selection applications in psychology. We demonstrate these advantages and contrast SSVS with lasso type penalization in an application to predict depression symptoms in a large sample and an accompanying simulation study. We investigate the effects of sample size, effect size, and patterns of correlation among predictors on rates of correct and false inclusion and bias in the estimates. SSVS as investigated here is reasonably computationally efficient and powerful to detect moderate effects in small sample sizes (or small effects in moderate sample sizes), while protecting against false inclusion and without over-penalizing true effects. We recommend SSVS as a flexible framework that is well-suited for the field, discuss limitations, and suggest directions for future development.

Retrospective Self-Reported Childhood Experiences in Enriched Environments Uniquely Predict Prosocial Behavior and Personality Traits in Adulthood.

What features of people's childhood environments go on to shape their prosocial behavior during adulthood? Past studies linking childhood environment to adult prosocial behavior have focused primarily on adverse features, thereby neglecting the possible influence of exposure to enriched environments (e.g., access to material resources, experiences with rich cooperative relationships, and interactions with morally exemplary role models). Here, we expand the investigation of childhood environmental quality to include consideration of enriching childhood experiences and their relation to adult prosociality. In two cross-sectional studies, we found promising evidence that enriched childhood environments are associated with adult moral behavior. In study 1 (N = 1,084 MTurk workers), we adapted an existing measure of enriched childhood environmental quality for retrospective recall of childhood experiences and found that subjects' recollections of their enriched childhood experiences are distinct from their recollections of adverse childhood experiences. In Study 2 (N = 2,208 MTurk workers), we found that a formative composite of subjects' recollections of enriched childhood experiences is positively associated with a variety of morally relevant traits in adulthood, including agreeableness, honesty-humility, altruism, endorsement of the principle of care, empathic responding to the plights of needy others, and charitable donations in an experimental setting, and that these associations held after controlling for childhood environmental adversity, childhood socioeconomic status, sex, and age. We also found evidence suggesting that some, but not all, of the relationship between enrichment and adult prosociality can be explained by a shared genetic correlation. We include a new seven-item measure as an appendix.

An evolutionary psychology view of forgiveness: individuals, groups, and culture.

We review the logic of an evolutionary perspective on forgiveness, highlighting how insight into the likely function of forgiveness - solving adaptive problems related to acquiring and maintaining social relationships - has productively guided research and theory. A combination of experimental, longitudinal, cross-sectional, and cross-cultural evidence supports the claim that victims' perceptions of harmdoers' relationship value and exploitation risk causally influence whether or not victims forgive harmdoers. We also review the nascent literature on the topic of intergroup forgiveness and consider how the concepts associated with interpersonal forgiveness, such as apologies, relationship value, and exploitation risk, might help us understand forgiveness between groups, cultures, and societies. Finally, we explore the intersection of evolutionary and cultural perspectives on forgiveness, and consider how concepts from these two research traditions might be integrated to help us understand forgiveness even better.

Syndemics and salivary inflammation in people living with HIV/AIDS.

OBJECTIVE: People living with HIV/AIDS (PLWHA) are disproportionally exposed to a host of structural, community, and individual-level physical and psychosocial stressors also termed 'syndemic conditions.' The current study aimed to examine the association between experiencing syndemic conditions and physiological stress response and be associated with bodily inflammation, including Interlekin-6 (IL-6) and C-reactive protein (CRP) in PLWHA. DESIGN: Participants (N = 103) were recruited from a public HIV clinic. They provided saliva samples of IL-6 and CRP and completed psychosocial measures. MAIN OUTCOME MEASURES: Levels of circulating salivary IL-6 and CRP. RESULTS: When predictors (birth country, recent housing instability, and incarceration history) were simultaneously entered into a regression model, only incarceration history was negatively associated with IL-6 [b = -.27, t(98) = -3.11, p = .002]. For CRP, the resulting regression model was not significant, [F(3, 98) = 2.23, p = .090]. CONCLUSION: Although we had expected higher levels of syndemics to be associated with higher levels of circulating inflammation, in our sample, length of incarceration was associated with lower levels of circulating IL-6. Findings are therefore suggestive of a stress response disruption resulting in a negative feedback loop as the long-term impact of chronic stress on inflammation.

The sex premium in religiously motivated moral judgment.

Recent theorizing suggests that religious people's moral convictions are quite strategic (albeit unconsciously so), designed to make their worlds more amenable to their favored approaches to solving life's basic challenges. In a meta-analysis of 5 experiments and a preregistered replication, we find that religious identity places a sex premium on moral judgments, causing people to judge violations of conventional sexual morality as particularly objectionable. The sex premium is especially strong among highly religious people, and applies to both legal and illegal acts. Religion's influence on moral reasoning emphasizes conventional sexual norms, and may reflect the strategic projects to which religion has been applied throughout history. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Forgiveness takes place on an attitudinal continuum from hostility to friendliness: Toward a closer union of forgiveness theory and measurement.

Researchers commonly conceptualize forgiveness as a rich complex of psychological changes involving attitudes, emotions, and behaviors. Psychometric work with the measures developed to capture this conceptual richness, however, often points to a simpler picture of the psychological dimensions in which forgiveness takes place. In an effort to better unite forgiveness theory and measurement, we evaluate several psychometric models for common measures of forgiveness. In doing so, we study people from the United States and Japan to understand forgiveness in both nonclose and close relationships. In addition, we assess the predictive utility of these models for several behavioral outcomes that traditionally have been linked to forgiveness motives. Finally, we use the methods of item response theory, which place person abilities and item responses on the same metric and, thus, help us draw psychological inferences from the ordering of item difficulties. Our results highlight models based on correlated factors models and bifactor (S-1) models. The bifactor (S-1) model evinced particular utility: Its general factor consistently predicts variation in relevant criterion measures, including 4 different experimental economic games (when played with a transgressor), and also suffuses a second self-report measure of forgiveness. Moreover, the general factor of the bifactor (S-1) model identifies a single psychological dimension that runs from hostility to friendliness while also pointing to other sources of variance that may be conceived of as method factors. Taken together, these results suggest that forgiveness can be usefully conceptualized as prosocial change along a single attitudinal continuum that ranges from hostility to friendliness. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Sequential loss of tumor vessel pericytes and endothelial cells after inhibition of platelet-derived growth factor B by selective aptamer AX102.

Inhibition of platelet derived growth factor (PDGF) can increase the efficacy of other cancer therapeutics, but the cellular mechanism is incompletely understood. We examined the cellular effects on tumor vasculature of a novel DNA oligonucleotide aptamer (AX102) that selectively binds PDGF-B. Treatment with AX102 led to progressive reduction of pericytes, identified by PDGF receptor beta, NG2, desmin, or alpha-smooth muscle actin immunoreactivity, in Lewis lung carcinomas. The decrease ranged from 35% at 2 days, 63% at 7 days, to 85% at 28 days. Most tumor vessels that lacked pericytes at 7 days subsequently regressed. Overall tumor vascularity decreased 79% over 28 days, without a corresponding decrease in tumor size. Regression of pericytes and endothelial cells led to empty basement membrane sleeves, which were visible at 7 days, but only 54% remained at 28 days. PDGF-B inhibition had a less pronounced effect on pancreatic islet tumors in RIP-Tag2 transgenic mice, where pericytes decreased 47%, vascularity decreased 38%, and basement membrane sleeves decreased 21% over 28 days. Taken together, these findings show that inhibition of PDGF-B signaling can lead to regression of tumor vessels, but the magnitude is tumor specific and does not necessarily retard tumor growth. Loss of pericytes in tumors is an expected direct consequence of PDGF-B blockade, but reduced tumor vascularity is likely to be secondary to pericyte regression.

Renal artery stenosis evaluation: diagnostic performance of gadobenate dimeglumine-enhanced MR angiography--comparison with DSA.

PURPOSE: To prospectively determine diagnostic performance and safety of contrast material-enhanced (CE) magnetic resonance (MR) angiography with 0.1 mmol per kilogram of body weight gadobenate dimeglumine for depiction of significant steno-occlusive disease (> or =51% stenosis) of renal arteries, with digital subtraction angiography (DSA) as reference standard. MATERIALS AND METHODS: This multicenter study was approved by local institutional review boards; all patients provided written informed consent. Patient enrollment and examination at centers in the United States complied with HIPAA. Two hundred ninety-three patients (154 men, 139 women; mean age, 61.0 years) with severe hypertension (82.2%), progressive renal failure (11.3%), and suspected renal artery stenosis (6.5%) underwent CE MR angiography with three-dimensional spoiled gradient-echo sequences after administration of 0.1 mmol/kg gadobenate dimeglumine at 2 mL/sec. Anteroposterior and oblique DSA was performed in 268 (91.5%) patients. Three independent blinded reviewers evaluated CE MR angiographic images. Sensitivity, specificity, and accuracy of CE MR angiography for detection of significant steno-occlusive disease (> or =51% vessel lumen narrowing) were determined at segment (main renal artery) and patient levels. Positive and negative predictive values and positive and negative likelihood ratios were determined. Interobserver agreement was analyzed with generalized kappa statistics. A safety evaluation (clinical examination, electrocardiogram, blood and urine analysis, monitoring for adverse events) was performed. RESULTS: Of 268 patients, 178 who were evaluated with MR angiography and DSA had significant steno-occlusive disease of renal arteries at DSA. Sensitivity, specificity, and accuracy of CE MR angiography for detection of 51% or greater stenosis or occlusion were 60.1%-84.1%, 89.4%-94.7%, and 80.4%-86.9%, respectively, at segment level. Similar values were obtained for predictive values and for patient-level analyses. Few CE MR angiographic examinations (1.9%-2.8%) were technically inadequate. Interobserver agreement for detection of significant steno-occlusive disease was good (79.9% agreement; kappa = 0.69). No safety concerns were noted. CONCLUSION: CE MR angiography performed with 0.1 mmol/kg gadobenate dimeglumine, compared with DSA, is safe and provides good sensitivity, specificity, and accuracy for detection of significant renal artery steno-occlusive disease.

Ocular Distribution and Pharmacokinetics of Lifitegrast in Pigmented Rabbits and Mass Balance in Beagle Dogs.

PURPOSE: Lifitegrast is approved in the United States for the treatment of dry eye disease (DED). We assessed lifitegrast's ocular distribution/pharmacokinetic profile in rabbits, and 14C-lifitegrast mass balance/excretion in dogs. METHODS: Female pigmented rabbits received a single topical ocular dose of lifitegrast (Formulation No. 1, n = 25; No. 2, n = 25) per eye twice daily (target, 1.75 mg/eye/dose). Blood/ocular tissues were collected on day 5. Beagle dogs received single intravenous (n = 10; target, 3 mg, 262 µCi/animal) and ocular (n = 8, target, 3 mg, 30 µCi/eye) doses of 14C-lifitegrast (∼8 weeks between doses). Blood, excreta, and cage rinse/wipes were collected. Concentrations were measured by mass spectrometry/liquid scintillation counting. Pharmacokinetic analyses (noncompartmental) included maximum concentration (Cmax), time to Cmax (tmax), and area under the concentration-time curve from 0 to 8 h (AUC0-8). RESULTS: In rabbits, lifitegrast Cmax and AUC0-8 were similar between formulations. Cmax was highest in ocular anterior segment tissues: 5,190-14,200 ng/g [conjunctiva (palpebral/bulbar), cornea, anterior sclera]. Posterior segment tissues had lower concentrations (0-826 ng/g). AUC0-8 followed a similar trend. Plasma concentrations were low (Cmax <18 ng/mL). Tissue/plasma tmax was ∼0.25-1 h. In dogs, after intravenous/ocular doses, 14C-lifitegrast was eliminated primarily through feces. Excreted radioactivity was mainly unchanged lifitegrast. CONCLUSIONS: High exposure of lifitegrast in rabbit ocular anterior segment tissues and low exposure in posterior segment tissues/plasma suggests that lifitegrast reaches target tissues for DED treatment, with low potential for off-target systemic/ocular effects. Excretion of unchanged 14C-lifitegrast suggests minimal drug metabolism in vivo. This is consistent with lifitegrast clinical trial efficacy/safety data.

Treatment processes and demographic variables as predictors of dropout from trauma-focused cognitive behavioral therapy (TF-CBT) for youth.

OBJECTIVE: Premature dropout is a significant concern in trauma-focused psychotherapy for youth. Previous studies have primarily examined pre-treatment demographic and symptom-related predictors of dropout, but few consistent findings have been reported. The current study examined demographic, symptom, and in-session process variables as predictors of dropout from Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) for youth. METHOD: Participants were a diverse sample of Medicaid-eligible youth (ages 7-17; n = 108) and their nonoffending caregivers (n = 86), who received TF-CBT through an effectiveness study in a community setting. In-session process variables were coded from audio-recorded sessions, and these and pre-treatment demographic variables and symptom levels were examined as predictors of dropout prior to receiving an adequate dose of TF-CBT (<7 sessions). Twenty-nine children were classified as dropouts and 79 as completers. RESULTS: Binary logistic regression analyses revealed that higher levels of child and caregiver avoidance expressed during early sessions, as well as greater relationship difficulties between the child and therapist, predicted dropout. Those children who were in foster care during treatment were less likely to drop out than children living with parents or relatives. No other demographic or symptom-related factors predicted dropout. CONCLUSIONS: These findings highlight the importance of addressing avoidance and therapeutic relationship difficulties in early sessions of TF-CBT to help reduce dropout, and they have implications for improving efforts to disseminate evidence-based trauma-focused treatments.

A comparison study of bioanalytical methods for detection and characterization of anti-velaglucerase alfa antibodies.

AIM: To provide more efficient and timely immunogenicity testing service to support routine patient care, the original complex testing algorithm for evaluation of anti-velaglucerase alfa antibodies has been simplified and individual methods (screen, confirm, titer, neutralizing antibody [NAb] and IgE) have been redeveloped/optimized and validated. RESULTS: To compare the performance of different methods, 50 velaglucerase alfa-treated patient samples were analyzed using both old and new methods for the presence of antidrug antibodies (ADAs) and 31 ADA-positive samples were analyzed for neutralizing capacity. The ADA and NAb statuses are almost identical from both methods and both ADA and NAb titer results are highly correlated with a Spearman's correlation of 0.96 and 0.86, respectively. CONCLUSION: The original and new testing methods can be considered interchangeable for the measurement of total and neutralizing anti-velaglucerase alfa antibodies.

A comparison study of bioanalytical methods for characterization of anti-idursulfase antibodies.

AIM: Legacy methods with complex testing scheme for characterization of anti-idursulfase antibodies (ADA) were simplified and optimized in order to meet current regulatory guidance and provide more timely and cost-effective support for routine patient care. RESULTS: To compare the performance of the original and updated methods, patient samples receiving commercially prescribed Elaprase treatment were analyzed by both test methods. The ADA and neutralizing antibody results obtained by both methods were highly correlated and the updated method had an overall higher ADA and neutralizing antibody positive rates and higher ADA titers. CONCLUSION: The updated methods and test schemes are much simpler, more sensitive, but are also highly comparable with the original methods for the measurement of total and neutralizing ADA.

Constructive and Unproductive Processing of Traumatic Experiences in Trauma-Focused Cognitive-Behavioral Therapy for Youth.

Although there is substantial evidence to support the efficacy of cognitive-behavioral treatments (CBT) for posttraumatic stress disorder (PTSD), there is some debate about how these treatments have their effects. Modern learning theory and cognitive and emotional processing theories highlight the importance of reducing avoidance, facilitating the constructive processing of feared experiences, and strengthening new inhibitory learning. We examined variables thought to be associated with unproductive and constructive processing of traumatic experiences in a sample of 81 youth with elevated PTSD symptoms, who received Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) for abuse or traumatic interpersonal loss. Sessions during the trauma narrative phase of TF-CBT were coded for indicators of unproductive processing (overgeneralization, rumination, avoidance) and constructive processing (decentering, accommodation of corrective information), as well as levels of negative emotion. In previous analyses of this trial (Ready et al., 2015), more overgeneralization during the narrative phase predicted less improvement in internalizing symptoms at posttreatment and a worsening of externalizing symptoms over the 12-month follow-up. In contrast, more accommodation predicted improvement in internalizing symptoms and also moderated the negative effects of overgeneralization on internalizing and externalizing symptoms. The current study examined correlates of overgeneralization and accommodation. Overgeneralization was associated with more rumination, less decentering, and more negative emotion, suggesting immersion in trauma-related material. Accommodation was associated with less avoidance and more decentering, suggesting a healthy distance from trauma-related material that might allow for processing and cognitive change. Decentering also predicted improvement in externalizing symptoms at posttreatment. Rumination and avoidance showed important associations with overgeneralization and accommodation, respectively, but did not predict treatment outcomes. This study identifies correlates of overgeneralization and accommodation that might shed light on how these variables relate to unproductive and constructive processing of traumatic experiences.

2'-Deoxy purine, 2'-O-methyl pyrimidine (dRmY) aptamers as candidate therapeutics.

Aptamers are short oligonucleotides that fold into well-defined three-dimensional architectures thereby enabling specific binding to molecular targets such as proteins. To be successful as a novel therapeutic modality, it is important for aptamers to not only bind their targets with high specificity and affinity, but also to exhibit favorable properties with respect to in vivo stability, cost-effective synthesis, and tolerability (i.e., safety). We describe methods for generating aptamers comprising 2 - deoxy purines and 2 -O-methyl pyrimidines (dRmY) that broadly satisfy many of these additional constraints. Conditions under which dRmY transcripts can be efficiently synthesized using mutant T7 RNA polymerases have been identified and used to generate large libraries from which dRmY aptamers to multiple target proteins, including interleukin (IL)-23 and thrombin, have been successfully discovered using the SELEX process. dRmY aptamers are shown to be highly nuclease-resistant, long-lived in vivo, efficiently synthesized, and capable of binding protein targets in a manner that inhibits their biologic activity with K(D) values in the low nM range. We believe that dRmY aptamers have considerable potential as a new class of therapeutic aptamers.

Direct in vitro selection of a 2'-O-methyl aptamer to VEGF.

Aptamers (protein binding oligonucleotides) have potential as a new class of targeted therapeutics. For applications requiring chronic systemic administration, aptamers must achieve high-affinity target binding while simultaneously retaining high in vivo stability, tolerability, and ease of chemical synthesis. To this end, we describe a method for generating aptamers composed entirely of 2'-O-methyl nucleotides (mRmY). We present conditions under which 2'-O-methyl transcripts can be generated directly and use these conditions to select a fully 2'-O-methyl aptamer from a library of 3 x 10(15) unique 2'-O-methyl transcripts. This aptamer, ARC245, is 23 nucleotides in length, binds to vascular endothelial growth factor (VEGF) with a Kd of 2 nM, and inhibits VEGF activity in cellular assays. Notably, ARC245 is so stable that degradation cannot be detected after 96 hr in plasma at 37 degrees C or after autoclaving at 125 degrees C. We believe ARC245 has considerable potential as an antiangiogenesis therapeutic.

Biodistribution of Idursulfase Formulated for Intrathecal Use (Idursulfase-IT) in Cynomolgus Monkeys after Intrathecal Lumbar Administration.

Enzyme replacement therapy with intravenous idursulfase (recombinant iduronate-2-sulfatase) is approved for the treatment of Hunter syndrome. Intravenous administration does not, however, treat the neurological manifestations, due to its low central nervous system bioavailability. Using intrathecal-lumbar administration, iduronate-2-sulfatase is delivered directly to the central nervous system. This study investigates the central nervous system biodistribution of intrathecal-lumbar administered iduronate-2-sulfatase in cynomolgus monkeys. Twelve monkeys were administered iduronate-2-sulfatase in one 30 mg intrathecal-lumbar injection. Brain, spinal cord, liver, and kidneys were collected for iduronate-2-sulfatase concentration (measured by an enzyme linked immunosorbent assay) and enzyme activity measurement (via a method utilizing 4-methylumbelliferyl-α-iduronate-2-sulfate) at 1, 2, 5, 12, 24, and 48 hours following administration. The tissue enzyme linked immunosorbent assay confirmed iduronate-2-sulfatase uptake to the brain, spinal cord, kidneys, and liver in a time-dependent manner. In spinal cord and brain, iduronate-2-sulfatase appeared as early as 1 hour following administration, and peak concentrations were observed at ~2 and ~5 hours. Iduronate-2-sulfatase appeared in liver and kidneys 1 hour post intrathecal-lumbar dose with peak concentrations between 5 and 24 hours. Liver iduronate-2-sulfatase concentration was approximately 10-fold higher than kidney. The iduronate-2-sulfatase localization and enzyme activity in the central nervous system, following intrathecal administration, demonstrates that intrathecal-lumbar treatment with iduronate-2-sulfatase may be considered for further investigation as a treatment for Hunter syndrome patients with neurocognitive impairment.

A novel LC-MS/MS assay for heparan sulfate screening in the cerebrospinal fluid of mucopolysaccharidosis IIIA patients.

AIMS: Heparan sulfate (HS) accumulates in the central nervous system in mucopolysaccharidosis III type A (MPS IIIA). A validated LC-MS/MS assay was developed to measure HS in human cerebrospinal fluid (CSF). METHODS & RESULTS: HS was extracted and digested and the resultant disaccharides were derivatized with a novel label, 4-butylaniline, enabling isoform separation and isotope-tagged analog introduction as an internal standard for LC-MS/MS. The assay has a LLOQ for disaccharides of 0.1 µM, ±20% accuracy and ≤20% precision. CSF samples from patients with MPS IIIA showed elevated HS levels (mean 4.9 µM) compared with negative controls (0.37 µM). CONCLUSION: This assay detected elevated HS levels in the CSF of patients with MPS IIIA and provides a method to assess experimental therapies.