Elevated TNF-α is associated with pain and physical disability in mucopolysaccharidosis types I, II, and VI

Open-label, single-center, clinical study evaluating the safety, tolerability and clinical effects of pentosan polysulfate sodium in subjects with mucopolysaccharidosis I

Lysosomal enzyme deficiency in mucopolysaccharidosis (MPS) I results in glycosaminoglycan (GAG) accumulation leading to pain and limited physical function. Disease-modifying treatments for MPS I, enzyme replacement, and hematopoietic stem cell therapy (HSCT), do not completely resolve MPS I symptoms, particularly skeletal manifestations. The GAG reduction, anti-inflammatory, analgesic, and tissue remodeling properties of pentosan polysulfate sodium (PPS) may provide disease-modifying treatment for musculoskeletal symptoms and joint inflammation in MPS I following ERT and/or HSCT. The safety and efficacy of PPS were evaluated in four subjects with MPS I aged 14-19 years, previously treated with ERT and/or HSCT. Subjects received doses of 0.75 mg/kg or 1.5 mg/kg PPS via subcutaneous injections weekly for 12 weeks, then every 2 weeks for up to 72 weeks. PPS was well tolerated at both doses with no serious adverse events. MPS I GAG fragment (UA-HNAc [1S]) levels decreased at 73 weeks. Cartilage degradation biomarkers serum C-telopeptide of crosslinked collagen (CTX) type I (CTX-I) and type II (CTX-II) and urine CTX-II decreased in all subjects through 73 weeks. PROMIS scores for pain interference, pain behavior, and fatigue decreased in all subjects through 73 weeks. Physical function, measured by walking distance and dominant hand function, improved at 49 and 73 weeks. Decreased GAG fragments and cartilage degradation biomarkers, and positive PROMIS outcomes support continued study of PPS as a potential disease-modifying treatment for MPS I with improved pain and function outcomes.

Evaluation of etanercept (a tumor necrosis factor alpha inhibitor) as an effective treatment for joint disease in mucopolysaccharidosis type I. A case report with whole-body magnetic resonance imaging

Summary

A 12-year-old girl with mucopolysaccharidosis (MPS) type I (Gurler-Scheie syndrome, Q70X/del C683 of the IDUA gene in the compound heterozygous state) regularly received enzyme replacement therapy (laronidase) since the preclinical stage (6 months old) due to positive family history, and started etanercept treatment due to progression of joint pain and decreasing capability to walk. The patient had a significant reduction of pain in the joints and an expansion of daily physical activity without adverse events. A decrease in bone marrow edema without foci progression compared to baseline assessment was observed in the whole-body MRI.During the treatment (baseline/6 months/12 months) the following was observed: childhood health assessment questionnaire (CHAQ) index of 1.88/2.13/1.63 points; patient's pediatric quality of life inventory (PedsQL) of 37/30/31 points; parental PedsQL of 26/27/34 points; and patient's pain visual-analog scale (VAS) of 75/45/40, with no VAS recorded for the mother. Juvenile arthritis functional assessment report (JAFAR) scores of 35/34/8 points were observed. A significant reduction in the taking of NSAIDs was observed. In the second half of the year, the nasal breathing became normal, and remission in chronic rhinitis and adenoiditis was achieved (no infection episodes) without otitis episodes.

Conclusion

Etanercept in mucopolysaccharidosis type 1 is safe and well tolerated. The reduction of joint pain and increased walking capacity were observed. A decreased number of respiratory infection episodes and nasal breathing improvement were noted during the treatment. The observation shows the role of inflammation in the different aspects of MPS. Further investigations on immune system dysregulation in patients with MPS I are needed. Additional studies on the efficacy and safety of anti-rheumatic biological drugs in patients with MPSI are required.

Glycosaminoglycan-induced proinflammatory cytokine levels as disease marker in mucopolysaccharidosis

Recently, it has been shown disturbances in oxidant/antioxidant system and increases in some inflammatory markers in animal studies and in some Mucopolysaccharidoses (MPSs) patients. In this study, we aimed to determine the oxidative stress/antioxidant parameters and pro-inflammatory cytokine levels in the serum of MPS patients, in order to evaluate the possible role of inflammation in these patient groups regarding to accumulated metabolites. MPS I (n = 3), MPS II (n = 8), MPS III (n = 4), MPS IVA (n = 3), MPS VI (n = 3), and VII (n = 1) patients and 20 age-matched healthy subjects were included into the study. There was no statistically significant change in activities of SOD, Catalase, GSH-Px and lipid peroxidation levels in erythrocytes between the MPS patients and healthy controls. While IL-1alpha (p = 0.054), IL-6 (p = 0.008) levels, and chitotriosidase activity (p = 0.003) elevated in MPS3 patients, IL1α (p = 0.006), IL-1β (p = 0.006), IL-6 (p = 0.006), IFNγ (p = 0.006), and NFκB (p = 0.006) levels increased in MPS-6 patients. Elevated levels of IL-6, IL1α and chitotriosidase activity demonstrated macrophage activation in MPSIII untreated with enzyme replacement. Our study showed for the first time that high levels of IL1α, IL-6, IL1β and NFκB were present in MPSVI patients, demonstrating the induction of inflammation by dermatan sulphate. The low level of paraoxonase in MPSVI patients may be a good marker for cardiac involvement. Overall, this study provides important insights into the relationship between lysosomal storage of glycosaminoglycan and inflammation in MPS patients. It highlights possible pathways for the increased release of inflammatory molecules and suggests new targets for the development of treatments.

Femoral Structure and Biomechanical Characteristics in Sanfilippo Syndrome Type-B Mice

Sanfilippo syndrome Type-B, also known as mucopolysaccharidosis IIIB (MPS IIIB), accounts for approximately one-third of all Sanfilippo syndrome patients and is characterized by a similar natural history as Type-A. Patients suffer from developmental regression, bone malformation, organomegaly, GI distress, and profound neurological deficits. Despite human trials of enzyme replacement therapy (ERT) (SBC-103, AX250) in MPS IIIB, there is currently no FDA approved treatment and a few palliative options. The major concerns of ERT and gene therapy for the treatment of bone malformation are the inadequate biodistribution of the missing enzyme, N-acetyl-α-glucosaminidase (NAGLU), and that the skeleton is a poorly hit target tissue in ERT and gene therapy. Each of the four known human types of MPS III (A, B, C, and D) is usually regarded as having mild bone manifestations, yet it remains poorly characterized. This study aimed to determine bone mineral content (BMC), volumetric bone mineral density (vBMD), and biomechanical properties in femurs MPS IIIB C57BL/6 mice compared to phenotypic control C57BL/6 mice. Significant differences were observed in MPS IIIB mice within various cortical and cancellous bone parameters for both males and females (p < 0.05). Here, we establish some osteogenic manifestations of MPS IIIB within the mouse model by radiographic and biomechanical tests, which are also differentially affected by age and sex. This suggests that some skeletal features of the MPS IIIB mouse model may be used as biomarkers of peripheral disease correction for preclinical treatment of MPS IIIB.

An Innovative Tool for Evidence-Based, Personalized Treatment Trials in Mucopolysaccharidosis

Mucopolysaccharidosis (MPS) is a group of rare metabolic diseases associated with reduced life expectancy and a substantial unmet medical need. Immunomodulatory drugs could be a relevant treatment approach for MPS patients, although they are not licensed for this population. Therefore, we aim to provide evidence justifying fast access to innovative individual treatment trials (ITTs) with immunomodulators and a high-quality evaluation of drug effects by implementing a risk-benefit model for MPS. The iterative methodology of our developed decision analysis framework (DAF) consists of the following steps: (i) a comprehensive literature analysis on promising treatment targets and immunomodulators for MPS; (ii) a quantitative risk-benefit assessment (RBA) of selected molecules; and (iii) allocation phenotypic profiles and a quantitative assessment. These steps allow for the personalized use of the model and are in accordance with expert and patient representatives. The following four promising immunomodulators were identified: adalimumab, abatacept, anakinra, and cladribine. An improvement in mobility is most likely with adalimumab, while anakinra might be the treatment of choice for patients with neurocognitive involvement. Nevertheless, a RBA should always be completed on an individual basis. Our evidence-based DAF model for ITTs directly addresses the substantial unmet medical need in MPS and characterizes a first approach toward precision medicine with immunomodulatory drugs.

Redox Imbalance in Neurological Disorders in Adults and Children

Oxygen is a central molecule for numerous metabolic and cytophysiological processes, and, indeed, its imbalance can lead to numerous pathological consequences. In the human body, the brain is an aerobic organ and for this reason, it is very sensitive to oxygen equilibrium. The consequences of oxygen imbalance are especially devastating when occurring in this organ. Indeed, oxygen imbalance can lead to hypoxia, hyperoxia, protein misfolding, mitochondria dysfunction, alterations in heme metabolism and neuroinflammation. Consequently, these dysfunctions can cause numerous neurological alterations, both in the pediatric life and in the adult ages. These disorders share numerous common pathways, most of which are consequent to redox imbalance. In this review, we will focus on the dysfunctions present in neurodegenerative disorders (specifically Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis) and pediatric neurological disorders (X-adrenoleukodystrophies, spinal muscular atrophy, mucopolysaccharidoses and Pelizaeus-Merzbacher Disease), highlighting their underlining dysfunction in redox and identifying potential therapeutic strategies.

Proteomics identifies novel biomarkers of synovial joint disease in a canine model of mucopolysaccharidosis I

Mucopolysaccharidosis I is a lysosomal storage disorder characterized by deficient alpha-L-iduronidase activity, leading to abnormal accumulation of glycosaminoglycans in cells and tissues. Synovial joint disease is prevalent and significantly reduces patient quality of life. There is a critical need for improved understanding of joint disease pathophysiology in MPS I, including specific biomarkers to predict and monitor joint disease progression, and response to treatment. The objective of this study was to leverage the naturally-occurring MPS I canine model and undertake an unbiased proteomic screen to identify systemic biomarkers predictive of local joint disease in MPS I. Synovial fluid and serum samples were collected from MPS I and healthy dogs at 12 months-of-age, and protein abundance characterized using liquid chromatography tandem mass spectrometry. Stifle joints were evaluated postmortem using magnetic resonance imaging (MRI) and histology. Proteomics identified 40 proteins for which abundance was significantly correlated between serum and synovial fluid, including markers of inflammatory joint disease and lysosomal dysfunction. Elevated expression of three biomarker candidates, matrix metalloproteinase 19, inter-alpha-trypsin inhibitor heavy-chain 3 and alpha-1-microglobulin, was confirmed in MPS I cartilage, and serum abundance of these molecules was found to correlate with MRI and histological degenerative grades. The candidate biomarkers identified have the potential to improve patient care by facilitating minimally-invasive, specific assessment of joint disease progression and response to therapeutic intervention.

Current and new therapies for mucopolysaccharidoses

The mucopolysaccharidoses (MPSs) are a subset of lysosomal storage diseases caused by deficiencies in the enzymes required to metabolize glycosaminoglycans (GAGs), a group of extracellular heteropolysaccharides that play diverse roles in human physiology. As a result, GAGs accumulate in multiple tissues, and affected patients typically develop progressive, multi-systemic symptoms in early childhood. Over the last 30 years, the treatments available for the MPSs have evolved tremendously. There are now multiple therapies that delay the progression of these debilitating disorders, although their effectiveness varies according to MPS sub-type. In this review, we discuss the basic principle underlying MPS treatment (enzymatic "cross correction"), and we review the three general modalities currently available: hematopoietic stem cell transplantation, enzymatic replacement, and gene therapy. For each treatment type, we discuss its effectiveness across the MPS subtypes, its inherent risks, and future directions. Long term, we suspect that treatment for the MPSs will continue to evolve, and through a combination of early diagnosis and effective management, these patients will continue to live longer lives with improved outcomes for quality of life.

Mucopolysaccharidosis: What Pediatric Rheumatologists and Orthopedics Need to Know

Mucopolysaccharidosis (MPS) is a group of disorders caused by the reduced or absent activity of enzymes involved in the glycosaminoglycans (GAGs) degradation; the consequence is the progressive accumulation of the substrate (dermatan, heparan, keratan or chondroitin sulfate) in the lysosomes of cells belonging to several tissues. The rarity, the broad spectrum of manifestations, the lack of strict genotype-phenotype association, and the progressive nature of MPS make diagnosing this group of conditions challenging. Musculoskeletal involvement represents a common and prominent feature of MPS. Joint and bone abnormalities might be the main clue for diagnosing MPS, especially in attenuated phenotypes; therefore, it is essential to increase the awareness of these conditions among the pediatric rheumatology and orthopedic communities since early diagnosis and treatment are crucial to reduce the disease burden of these patients. Nowadays, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are available for some MPS types. We describe the musculoskeletal characteristics of MPS patients through a literature review of MPS cases misdiagnosed as having rheumatologic or orthopedic conditions.

Assessment, pharmacological therapy and rehabilitation management of musculoskeletal pain in children with mucopolysaccharidoses: a scoping review

Background

Pain of musculoskeletal origin is very common in young patients affected by Mucopolysaccharidoses. This scoping review evaluates the evidence for assessment, pharmacological treatment and rehabilitation management for musculoskeletal pain of the latter.

Methods

A Medline search through PubMed has been performed for studies published in English at least for the past twenty years. Two investigators independently reviewed all search results and extracted those that met the inclusion criteria.

Results

29 studies have been selected and analysed in depth, of which 10 related to pain assessment, 11 concerned pharmacological approach, and 8 reported rehabilitation approaches.

Conclusion

Few data are available in literature concerning the classification and management of pain in children with Mucopolysaccharidoses. Notwithstanding, pain evaluation methods are effectively used to classify pain intensity, according to the age group and communication abilities of young Mucopolysaccharidoses patients. The review emphasizes that drug therapies have a palliative purpose, while rehabilitation reduces musculoskeletal pain and can provide a therapeutic effect on disabilities.

Non-cardiac Manifestations in Adult Patients With Mucopolysaccharidosis

Mucopolysaccharidoses (MPS) are a heterogeneous group of disorders that results in the absence or deficiency of lysosomal enzymes, leading to an inappropriate storage of glycosaminoglycans (GAGs) in various tissues of the body such as bones, cartilage, heart valves, arteries, upper airways, cornea, teeth, liver and nervous system. Clinical manifestations can become progressively exacerbated with age and affect their quality of life. Developments in advanced supportive treatment options such as enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT) may have improved patients' life span. Adult MPS patients require specialist clinical surveillance long-term. In many cases, in addition to the MPS-related health problems, they may develop age-related complications. Considering the complexity of their clinical manifestations and lack of guidelines on the management of adult MPS disorders, multispecialty and multidisciplinary teams' care is essential to diagnose and treat health problems that are likely to be encountered. This review presents non-cardiac clinical manifestations, their pathophysiology, management and long-term outcomes in adult MPS patients.

Innate Immunity in Mucopolysaccharide Diseases

Mucopolysaccharidoses are rare paediatric lysosomal storage disorders, characterised by accumulation of glycosaminoglycans within lysosomes. This is caused by deficiencies in lysosomal enzymes involved in degradation of these molecules. Dependent on disease, progressive build-up of sugars may lead to musculoskeletal abnormalities and multi-organ failure, and in others, to cognitive decline, which is still a challenge for current therapies. The worsening of neuropathology, observed in patients following recovery from flu-like infections, suggests that inflammation is highly implicated in disease progression. This review provides an overview of the pathological features associated with the mucopolysaccharidoses and summarises current knowledge regarding the inflammatory responses observed in the central nervous system and periphery. We propose a model whereby progressive accumulation of glycosaminoglycans elicits an innate immune response, initiated by the Toll-like receptor 4 pathway, but also precipitated by secondary storage components. Its activation induces cells of the immune system to release pro-inflammatory cytokines, such as TNF-α and IL-1, which induce progression through chronic neuroinflammation. While TNF-α is mostly associated with bone and joint disease in mucopolysaccharidoses, increasing evidence implicates IL-1 as a main effector of innate immunity in the central nervous system. The (NOD)-like receptor protein 3 inflammasome is therefore implicated in chronic neuroinflammation and should be investigated further to identify novel anti-inflammatory treatments.

Mucopolysaccharidosis Type VI, an Updated Overview of the Disease

Mucopolysaccharidosis type VI, or Maroteaux-Lamy syndrome, is a rare, autosomal recessive genetic disease, mainly affecting the pediatric age group. The disease is due to pathogenic variants of the ARSB gene, coding for the lysosomal hydrolase N-acetylgalactosamine 4-sulfatase (arylsulfatase B, ASB). The enzyme deficit causes a pathological accumulation of the undegraded glycosaminoglycans dermatan-sulphate and chondroitin-sulphate, natural substrates of ASB activity. Intracellular and extracellular deposits progressively take to a pathological scenario, often severe, involving most organ-systems and generally starting from the osteoarticular apparatus. Neurocognitive and behavioral abilities, commonly described as maintained, have been actually investigated by few studies. The disease, first described in 1963, has a reported prevalence between 0.36 and 1.3 per 100,000 live births across the continents. With this paper, we wish to contribute an updated overview of the disease from the clinical, diagnostic, and therapeutic sides. The numerous in vitro and in vivo preclinical studies conducted in the last 10-15 years to dissect the disease pathogenesis, the efficacy of the available therapeutic treatment (enzyme replacement therapy), as well as new therapies under study are here described. This review also highlights the need to identify new disease biomarkers, potentially speeding up the diagnostic process and the monitoring of therapeutic efficacy.

MPS I: Early diagnosis, bone disease and treatment, where are we now?

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder characterized by α-L-iduronidase deficiency. Patients present with a broad spectrum of disease severity ranging from the most severe phenotype (Hurler) with devastating neurocognitive decline, bone disease and early death to intermediate (Hurler-Scheie) and more attenuated (Scheie) phenotypes, with a normal life expectancy. The most severely affected patients are preferably treated with hematopoietic stem cell transplantation, which halts the neurocognitive decline. Patients with more attenuated phenotypes are treated with enzyme replacement therapy. There are several challenges to be met in the treatment of MPS I patients. First, to optimize outcome, early recognition of the disease and clinical phenotype is needed to guide decisions on therapeutic strategies. Second, there is thus far no effective treatment available for MPS I bone disease. The pathophysiological mechanisms behind bone disease are largely unknown, limiting the development of effective therapeutic strategies. This article is a state of the art that comprehensively discusses three of the most urgent open issues in MPS I: early diagnosis of MPS I patients, pathophysiology of MPS I bone disease, and emerging therapeutic strategies for MPS I bone disease.

Long-term effect of hematopoietic cell transplantation on systemic inflammation in patients with mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are devastating inherited diseases treated with hematopoietic cell transplantation (HCT). However, disease progression, especially skeletal, still occurs in all patients. Secondary inflammation has been hypothesized to be a cause. To investigate whether systemic inflammation is present in untreated patients and to evaluate the effect of HCT on systemic inflammation, dried blood spots (n = 66) of patients with MPS (n = 33) treated with HCT between 2003 and 2019 were included. Time points consisted of pre-HCT and, for patients with MPS type I (MPS I), also at 1, 3, and 10 years of follow-up. Ninety-two markers of the OLINK inflammation panel were measured and compared with those of age-matched control subjects (n = 31) by using principal component analysis and Wilcoxon rank sum tests with correction. Median age at transplantation was 1.3 years (range, 0.2-4.8 years), and median time of pre-HCT sample to transplantation was 0.1 year. Normal leukocyte enzyme activity levels were achieved in 93% of patients post-HCT. Pretransplant samples showed clear separation of patients and control subjects. Markers that differentiated pre-HCT between control subjects and patients were mainly pro-inflammatory (50%) or related to bone homeostasis and extracellular matrix degradation (33%). After 10 years' follow-up, only 5 markers (receptor activator of nuclear factor kappa-Β ligand, osteoprotegerin, axis inhibition protein 1 [AXIN1], stem cell factor, and Fms-related tyrosine kinase 3 ligand) remained significantly increased, with a large fold change difference between patients with MPS I and control subjects. In conclusion, systemic inflammation is present in untreated MPS patients and is reduced upon treatment with HCT. Markers related to bone homeostasis remain elevated up to 10 years after HCT and possibly reflect the ongoing skeletal disease, making them potential biomarkers for the evaluation of new therapies.

Brain delivery and activity of a lysosomal enzyme using a blood-brain barrier transport vehicle in mice

Most lysosomal storage diseases (LSDs) involve progressive central nervous system (CNS) impairment, resulting from deficiency of a lysosomal enzyme. Treatment of neuronopathic LSDs remains a considerable challenge, as approved intravenously administered enzyme therapies are ineffective in modifying CNS disease because they do not effectively cross the blood-brain barrier (BBB). We describe a therapeutic platform for increasing the brain exposure of enzyme replacement therapies. The enzyme transport vehicle (ETV) is a lysosomal enzyme fused to an Fc domain that has been engineered to bind to the transferrin receptor, which facilitates receptor-mediated transcytosis across the BBB. We demonstrate that ETV fusions containing iduronate 2-sulfatase (ETV:IDS), the lysosomal enzyme deficient in mucopolysaccharidosis type II, exhibited high intrinsic activity and degraded accumulated substrates in both IDS-deficient cell and in vivo models. ETV substantially improved brain delivery of IDS in a preclinical model of disease, enabling enhanced cellular distribution to neurons, astrocytes, and microglia throughout the brain. Improved brain exposure for ETV:IDS translated to a reduction in accumulated substrates in these CNS cell types and peripheral tissues and resulted in a complete correction of downstream disease-relevant pathologies in the brain, including secondary accumulation of lysosomal lipids, perturbed gene expression, neuroinflammation, and neuroaxonal damage. These data highlight the therapeutic potential of the ETV platform for LSDs and provide preclinical proof of concept for TV-enabled therapeutics to treat CNS diseases more broadly.

Biomarkers for prediction of skeletal disease progression in mucopolysaccharidosis type I

BACKGROUND

Orthopedic disease progresses in mucopolysaccharidosis type I (MPS I), even with approved therapies and remains a major factor in persistent suffering and disability. Novel therapies and accurate predictors of response are needed. The primary objective of this study was to identify surrogate biomarkers of future change in orthopedic disease.

METHODS

As part of a 9-year observational study of MPS I, range-of-motion (ROM), height, pelvic radiographs were measured annually. Biomarkers in year 1 were compared to healthy controls. Linear regression tested for associations of change in biomarkers over the first year with change in long-term outcomes.

RESULTS

MPS I participants (N = 19) were age 5 to 16 years and on average 6.9 ± 2.9 years post treatment initiation. Healthy controls (N = 51) were age 9 to 17 years. Plasma IL-1β, TNF-α, osteocalcin, pyridinolines, and deoxypyridinolines were higher in MPS than controls. Within MPS, progression of hip dysplasia was present in 46% to 77%. A 1 pg/mL increase in IL-6 was associated with -22°/year change in ROM (-28 to -15; P < .001), a 20 nmol/mmol creatinine/year increase in urine PYD was associated with a -0.024 Z-score/year change in height Z-score (-0.043 to -0.005; P = .016), and a 20 nmol/mmol creatinine/year increase in urine PYD was associated with a -2.0%/year change in hip dysplasia measured by Reimers migration index (-3.8 to -0.1; P = .037).

CONCLUSIONS

Inflammatory cytokines are high in MPS I. IL-6 and PYD were associated with progression in joint contracture, short stature, and hip dysplasia over time. Once validated, these biomarkers may prove useful for predicting response to treatment of skeletal disease in MPS I.

Therapy development for the mucopolysaccharidoses: Updated consensus recommendations for neuropsychological endpoints

Neurological dysfunction represents a significant clinical component of many of the mucopolysaccharidoses (also known as MPS disorders). The accurate and consistent assessment of neuropsychological function is essential to gain a greater understanding of the precise natural history of these conditions and to design effective clinical trials to evaluate the impact of therapies on the brain. In 2017, an International MPS Consensus Panel published recommendations for best practice in the design and conduct of clinical studies investigating the effects of therapies on cognitive function and adaptive behavior in patients with neuronopathic mucopolysaccharidoses. Based on an International MPS Consensus Conference held in February 2020, this article provides updated consensus recommendations and expands the objectives to include approaches for assessing behavioral and social-emotional state, caregiver burden and quality of life in patients with all mucopolysaccharidoses.

Therapeutic Options for Mucopolysaccharidoses: Current and Emerging Treatments

Mucopolysaccharidoses (MPS) are inborn errors of metabolism produced by a deficiency of one of the enzymes involved in the degradation of glycosaminoglycans (GAGs). Although taken separately, each type is rare. As a group, MPS are relatively frequent, with an overall estimated incidence of around 1 in 20,000-25,000 births. Development of therapeutic options for MPS, including hematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT), has modified the natural history of many MPS types. In spite of the improvement in some tissues and organs, significant challenges remain unsolved, including blood-brain barrier (BBB) penetration and treatment of lesions in avascular cartilage, heart valves, and corneas. Newer approaches, such as intrathecal ERT, ERT with fusion proteins to cross the BBB, gene therapy, substrate reduction therapy (SRT), chaperone therapy, and some combination of these strategies may provide better outcomes for MPS patients in the near future. As early diagnosis and early treatment are imperative to improve therapeutic efficacy, the inclusion of MPS in newborn screening programs should enhance the potential impact of treatment in reducing the morbidity associated with MPS diseases. In this review, we evaluate available treatments, including ERT and HSCT, and future treatments, such as gene therapy, SRT, and chaperone therapy, and describe the advantages and disadvantages. We also assess the current clinical endpoints and biomarkers used in clinical trials.

Recommendations for the management of MPS IVA: systematic evidence- and consensus-based guidance

INTRODUCTION

Mucopolysaccharidosis (MPS) IVA or Morquio A syndrome is an autosomal recessive lysosomal storage disorder (LSD) caused by deficiency of the N-acetylgalactosamine-6-sulfatase (GALNS) enzyme, which impairs lysosomal degradation of keratan sulphate and chondroitin-6-sulphate. The multiple clinical manifestations of MPS IVA present numerous challenges for management and necessitate the need for individualised treatment. Although treatment guidelines are available, the methodology used to develop this guidance has come under increased scrutiny. This programme was conducted to provide evidence-based, expert-agreed recommendations to optimise management of MPS IVA.

METHODS

Twenty six international healthcare professionals across multiple disciplines, with expertise in managing MPS IVA, and three patient advocates formed the Steering Committee (SC) and contributed to the development of this guidance. Representatives from six Patient Advocacy Groups (PAGs) were interviewed to gain insights on patient perspectives. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with experience managing patients with MPS IVA and the manuscript was evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers.

RESULTS

A total of 87 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) disease-modifying interventions (enzyme replacement therapy [ERT] and haematopoietic stem cell transplantation [HSCT]); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions (including spinal, limb, ophthalmic, cardio-thoracic and ear-nose-throat [ENT] surgeries). Consensus was reached on all statements after two rounds of voting. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance).

CONCLUSION

This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS IVA and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

Biomarkers in patients with mucopolysaccharidosis type II and IV

Glycosaminoglycans (GAGs), dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS), are the primary biomarkers in patients with mucopolysaccharidoses (MPS); however, little is known about other biomarkers. To explore potential biomarkers and their correlation with GAGs, blood samples were collected from 46 MPS II patients, 34 MPS IVA patients, and 5 MPS IVB patients. We evaluated the levels of 8 pro-inflammatory factors (EGF, IL-1β, IL-6, MIP-1α, TNF-α, MMP-1, MMP-2, and MMP-9), collagen type II, and DS, HS (HS0S, HSNS), and KS (mono-sulfated, di-sulfated) in blood. Eight biomarkers measured were significantly elevated in untreated MPS II patients, compared with those in normal controls: EGF, IL-1β, IL-6, HS0S, HSNS, DS, mono-sulfated KS, and di-sulfated KS. The same eight biomarkers remained elevated in ERT-treated patients. However, only three biomarkers remained elevated in post-HSCT MPS II patients: EGF, mono-sulfated KS, and di-sulfated KS. Post-HSCT patients with MPS II showed that IL-1β and IL-6 were normalized as HS and DS levels decreased. Eight biomarkers were significantly elevated in untreated MPS IVA patients: EGF, IL-1β, IL-6, MIP-1α, MMP-9, HSNS, mono-sulfated KS, and di-sulfated KS, and four biomarkers were elevated in MPS IVA patients under ERT: IL-6, TNF-α, mono-sulfated KS, and di-sulfated KS. There was no reduction of KS in the ERT-treated MPS IVA patient, compared with untreated patients. Two biomarkers were significantly elevated in untreated MPS IVB patients: IL-6 and TNF-α. Reversely, collagen type II level was significantly decreased in untreated and ERT-treated MPS II patients and untreated MPS IVA patients. In conclusion, selected pro-inflammatory factors can be potential biomarkers in patients with MPS II and IV as well as GAGs levels.

Recent trends in mucopolysaccharidosis research

Mucopolysaccharidosis (MPS) is a group of inherited conditions involving metabolic dysfunction. Lysosomal enzyme deficiency leads to the accumulation of glycosaminoglycan (GAG) resulting in systemic symptoms, and is categorized into seven types caused by deficiency in one of eleven different enzymes. The pathophysiological mechanism of these diseases has been investigated, indicating impaired autophagy in neuronal damage initiation, association of activated microglia and astrocytes with the neuroinflammatory processes, and involvement of tauopathy. A new inherited error of metabolism resulting in a multisystem disorder with features of the MPS was also identified. Additionally, new therapeutic methods are being developed that could improve conventional therapies, such as new recombinant enzymes that can penetrate the blood brain barrier, hematopoietic stem cell transplantation with reduced intensity conditioning, gene therapy using a viral vector system or gene editing, and substrate reduction therapy. In this review, we discuss the recent developments in MPS research and provide a framework for developing strategies.

New treatments for the mucopolysaccharidoses: from pathophysiology to therapy

Enzyme replacement therapy is currently considered the standard of care for the treatment of mucopolysaccharidoses (MPS) type I, II, VI, and IV. This approach has shown substantial efficacy mainly on somatic symptoms of the patients, but no benefit was found for other clinical manifestations, such as neurological involvement. New strategies are currently being tested to address these limitations, in particular to obtain sufficient therapeutic levels in the brain. Intrathecal delivery of recombinant enzymes or chimeric enzymes represent promising approaches in this respect. Further innovation will likely be introduced by the recent advancements in the knowledge of lysosomal biology and function. It is now clear that the clinical manifestations of MPS are not only the direct effects of storage, but also derive from a cascade of secondary events that lead to dysfunction of several cellular processes and pathways. Some of these pathways may represent novel therapeutic targets and allow for development of novel or adjunctive therapies for these disorders.

Pain in Mucopolysaccharidoses: Analysis of the Problem and Possible Treatments

Mucopolysaccharidosis (MPS) are a group of lysosomal storage disorders that are caused by the deficiency of enzymes involving in the catabolism of glycosaminoglycan (GAGs). GAGs incompletely degraded accumulate in many sites, damaging tissues and cells, leading to a variety of clinical manifestations. Many of these manifestations are painful, but few data are available in the literature concerning the prevalence, etiology, and pathogenesis of pain in children with MPS. This review, through the analysis of the data available the in literature, underscores the relevant prevalence of pain in MPSs’ children, provides the instruments to discern the etiopathogenesis of the disease and of pain, illustrates the available molecules for the management of pain and the possible advantages of non-pharmacological pain therapy in MPSs’ patients.

Recommendations for Evaluation and Management of Pain in Patients With Mucopolysaccharidosis in Latin America

The mucopolysaccharidosis (MPS) constitutes a heterogeneous group of rare genetic disorders caused by enzymatic deficiencies that lead to the accumulation of glycosaminoglycans. Several types of MPS are described, historically numbered from I to IX. Clinical observations strongly suggest the presence of chronic pain in patients with all types of MPS. There are few data in the literature on the evaluation and management of pain in these patients, a fact that can compromise the quality of life even more. Professionals with extensive experience in the care for patients with MPS held a meeting in April 2017 to discuss and propose recommendations for the evaluation and management of pain in patients with MPS in Latin America. This article summarizes the content of the discussions and presents the recommendations produced at the meeting. Patients with MPS present joint, bone, and muscle pain, as well as entrapment syndromes (spinal, optic nerve, carpal tunnel). The panel suggests the use of the following instruments for pain assessment: Face, Legs, Activity, Cry and Consolability Scale for children of up to four years of age and patients unable to communicate their pain; Child Health Assessment Questionnaire Scale; Facial Pain Scale and Numerical Pain Scale for patients of five to <18 years of age; Brief Pain Inventory and Short Form Health Survey 36 scales for patients aged 18 years or older. Based on the scores verified in these scales, the panel proposes pharmacological interventions for pain relief in this population of patients.

Targeting Chondroitin Sulfate Glycosaminoglycans to Treat Cardiac Fibrosis in Pathological Remodeling

Background:

Heart failure is a leading cause of mortality and morbidity, and the search for novel therapeutic approaches continues. In the monogenic disease mucopolysaccharidosis VI, loss-of-function mutations in arylsulfatase B lead to myocardial accumulation of chondroitin sulfate (CS) glycosaminoglycans, manifesting as myriad cardiac symptoms. Here, we studied changes in myocardial CS in nonmucopolysaccharidosis failing hearts and assessed its generic role in pathological cardiac remodeling.

Methods:

Healthy and diseased human and rat left ventricles were subjected to histological and immunostaining methods to analyze glycosaminoglycan distribution. Glycosaminoglycans were extracted and analyzed for quantitative and compositional changes with Alcian blue assay and liquid chromatography–mass spectrometry. Expression changes in 20 CS-related genes were studied in 3 primary human cardiac cell types and THP-1–derived macrophages under each of 9 in vitro stimulatory conditions. In 2 rat models of pathological remodeling induced by transverse aortic constriction or isoprenaline infusion, recombinant human arylsulfatase B (rhASB), clinically used as enzyme replacement therapy in mucopolysaccharidosis VI, was administered intravenously for 7 or 5 weeks, respectively. Cardiac function, myocardial fibrosis, and inflammation were assessed by echocardiography and histology. CS-interacting molecules were assessed with surface plasmon resonance, and a mechanism of action was verified in vitro.

Results:

Failing human hearts displayed significant perivascular and interstitial CS accumulation, particularly in regions of intense fibrosis. Relative composition of CS disaccharides remained unchanged. Transforming growth factor–β induced CS upregulation in cardiac fibroblasts. CS accumulation was also observed in both the pressure-overload and the isoprenaline models of pathological remodeling in rats. Early treatment with rhASB in the transverse aortic constriction model and delayed treatment in the isoprenaline model proved rhASB to be effective at preventing cardiac deterioration and augmenting functional recovery. Functional improvement was accompanied by reduced myocardial inflammation and overall fibrosis. Tumor necrosis factor–α was identified as a direct binding partner of CS glycosaminoglycan chains, and rhASB reduced tumor necrosis factor–α—induced inflammatory gene activation in vitro in endothelial cells and macrophages.

Conclusions:

CS glycosaminoglycans accumulate during cardiac pathological remodeling and mediate myocardial inflammation and fibrosis. rhASB targets CS effectively as a novel therapeutic approach for the treatment of heart failure.

WITHDRAWN: Recommendations for evaluation and management of pain in patients with mucopolysaccharidosis in Latin America

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.jpainsymman.2018.03.023. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Presentation and Treatments for Mucopolysaccharidosis Type II (MPS II; Hunter Syndrome)

INTRODUCTION

Mucopolysaccharidosis Type II (MPS II; Hunter syndrome) is an X- linked lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS). IDS deficiency leads to primary accumulation of dermatan sulfate (DS) and heparan sulfate (HS). MPS II is both multi-systemic and progressive. Phenotypes are classified as either attenuated or severe (based on absence or presence of central nervous system impairment, respectively).

AREAS COVERED

Current treatments available are intravenous enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), anti-inflammatory treatment, and palliative care with symptomatic surgeries. Clinical trials are being conducted for intrathecal ERT and gene therapy is under pre-clinical investigation. Treatment approaches differ based on age, clinical severity, prognosis, availability and feasibility of therapy, and health insurance.This review provides a historical account of MPS II treatment as well as treatment development with insights into benefits and/or limitations of each specific treatment.

EXPERT OPINION

Conventional ERT and HSCT coupled with surgical intervention and palliative therapy are currently the treatment options available to MPS II patients. Intrathecal ERT and gene therapy are currently under investigation as future therapies. These investigative treatments are critical to address the limitations in treatment of the central nervous system (CNS).

Pilot study of the safety and effect of adalimumab on pain, physical function, and musculoskeletal disease in mucopolysaccharidosis types I and II

Mucopolysaccharidosis I and II are lysosomal storage disorders that, despite treatment with hematopoietic cell transplantation (HCT) and/or enzyme replacement therapy (ERT), continue to cause significant skeletal abnormalities leading to pain, stiffness, physical dysfunction, and short stature. Tumor necrosis factor – alpha (TNF-α) is elevated in individuals with MPS I and II and associated with pain and physical dysfunction. Therefore, we evaluated the safety and effects of the TNF-α inhibitor adalimumab in patients with MPS I and II in a 32-week, randomized, double blind, placebo-controlled, crossover study of adalimumab at a dose of 20 mg (weight 15–<30 kg) or 40 mg (weight ≥ 30 kg) administered subcutaneously every other week or saline placebo for 16 weeks. Participants were evaluated at baseline, week 16, and week 32 with the Children's Health Questionnaire – Parent Form 50 (CHQ-PF50), the Pediatric Pain Questionnaire (PPQ), range-of-motion (ROM) measurements, anthropometry, six-minute walk test (6MWT), hand dynamometer, and laboratory evaluations for safety. The primary outcome was safety and primary efficacy outcome was bodily pain (BP) measured by the CHQ-PF50. Two subjects, one with MPS I and one with MPS II, completed the study. Adalimumab was well tolerated and there were no serious adverse events. Standardized BP scores for age and gender were higher (i.e. less pain) at the end of the treatment versus placebo phase for both subjects. Subject #1 became unblinded during treatment due to skin erythema. Behavior measured by both CHQ-PF50 and parental report improved during treatment compared to placebo in both subjects. ROM improved by > 5° in seven of eight joints in Subject #1 and five of eight joints in Subject #2 (range 7.0° to 52.8°). There was no change in the PPQ, 6MWT, or hand dynamometer. Data from this small pilot study suggest that treatment with adalimumab is safe, tolerable, and may improve ROM, physical function, and possibly pain, in children with MPS I or II. However, additional clinical trials are needed before this therapy should be recommended as part of clinical care.

Elevated cerebral spinal fluid biomarkers in children with mucopolysaccharidosis I-H

Mucopolysaccharidosis (MPS) type-IH is a lysosomal storage disease that results from mutations in the IDUA gene causing the accumulation of glycosaminoglycans (GAGs). Historically, children with the severe phenotype, MPS-IH (Hurler syndrome) develop progressive neurodegeneration with death in the first decade due to cardio-pulmonary complications. New data suggest that inflammation may play a role in MPS pathophysiology. To date there is almost no information on the pathophysiologic changes within the cerebral spinal fluid (CSF) of these patients. We evaluated the CSF of 25 consecutive patients with MPS-IH. While CSF glucose and total protein were within the normal range, we found a significantly mean elevated CSF opening pressure at 24 cm H₂O (range 14–37 cm H₂O). We observed a 3-fold elevation in CSF heparan sulfate and a 3–8 fold increase in MPS-IH specific non-reducing ends, I0S0 and I0S6. Cytokine analyses in CSF of children with MPS-IH showed significantly elevated inflammatory markers including: MCP-1 SDF-1a, IL-Ra, MIP-1b, IL-8, and VEGF in comparison to unaffected children. This is the largest report of CSF characteristics in children with MPS-IH. Identification of key biomarkers may provide further insight into the inflammatory-mediated mechanisms related to MPS diseases and perhaps lead to improved targeted therapies.

Oxidative and nitrative stress and pro-inflammatory cytokines in Mucopolysaccharidosis type II patients: effect of long-term enzyme replacement therapy and relation with glycosaminoglycan accumulation

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disease caused by a deficient activity of iduronate-2-sulfatase, leading to abnormal accumulation of glycosaminoglycans (GAG). The main treatment for MPS II is enzyme replacement therapy (ERT). Previous studies described potential benefits of six months of ERT against oxidative stress in patients. Thus, the aim of this study was to investigate oxidative, nitrative and inflammatory biomarkers in MPS II patients submitted to long term ERT. It were analyzed urine and blood samples from patients on ERT (mean time: 5.2years) and healthy controls. Patients presented increased levels of lipid peroxidation, assessed by urinary 15-F2t-isoprostane and plasmatic thiobarbituric acid-reactive substances. Concerning to protein damage, urinary di-tyrosine (di-Tyr) was increased in patients; however, sulfhydryl and carbonyl groups in plasma were not altered. It were also verified increased levels of urinary nitrate+nitrite and plasmatic nitric oxide (NO) in MPS II patients. Pro-inflammatory cytokines IL-1β and TNF-α were increased in treated patients. GAG levels were correlated to di-Tyr and nitrate+nitrite. Furthermore, IL-1β was positively correlated with TNF-α and NO. Contrastingly, we did not observed alterations in erythrocyte superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities, in reduced glutathione content and in the plasmatic antioxidant capacity. Although some parameters were still altered in MPS II patients, these results may suggest a protective role of long-term ERT against oxidative stress, especially upon oxidative damage to protein and enzymatic and non-enzymatic defenses. Moreover, the redox imbalance observed in treated patients seems to be GAG- and pro-inflammatory cytokine-related.