Articular chondrocytes from animals with a dermatan sulfate storage disease undergo a high rate of apoptosis and release nitric oxide and inflammatory cytokines: a possible mechanism underlying degenerative joint disease in the mucopolysaccharidoses

Mucopolysaccharidosis (MPS) Type VI (Maroteaux-Lamy Disease) is the lysosomal storage disease characterized by deficient arylsulfatase B activity and the resultant accumulation of dermatan sulfate-containing glycosaminoglycans (GAGs). A major feature of this and other MPS disorders is abnormal cartilage and bone development leading to short stature, dysostosis multiplex, and degenerative joint disease. To investigate the underlying cause(s) of degenerative joint disease in the MPS disorders, articular cartilage and cultured articular chondrocytes were examined from rats and cats with MPS VI. An age-progressive increase in the number of apoptotic chondrocytes was identified in the MPS animals by terminal transferase nick-end translation (TUNEL) staining and by immunohistochemical staining with anti-poly (ADP-ribose) polymerase (PARP) antibodies. Articular chondrocytes grown from these animals also released more nitric oxide (NO) and tumor necrosis factor alpha (TNF-alpha) into the culture media than did control chondrocytes. Notably, dermatan sulfate, the GAG that accumulates in MPS VI cells, induced NO release from normal chondrocytes, suggesting that GAG accumulation was responsible, in part, for the enhanced cell death in the MPS cells. Coculture of normal chondrocytes with MPS VI cells reduced the amount of NO release, presumably because of the release of arylsulfatase B by the normal cells and reuptake by the mutant cells. As a result of the enhanced chondrocyte death, marked proteoglycan and collagen depletion was observed in the MPS articular cartilage matrix. These results demonstrate that MPS VI articular chondrocytes undergo cell death at a higher rate than normal cells, because of either increased levels of dermatan sulfate and/or the presence of inflammatory cytokines in the MPS joints. In turn, this leads to abnormal cartilage matrix homeostasis in the MPS individuals, which further exacerbates the joint deformities characteristic of these disorders.

Neurosurgical interventions in children with Maroteaux-Lamy syndrome. Case report and review of the literature

This paper reports the case of a 14-year-old child with Maroteaux-Lamy syndrome (mucopolysaccharidosis type 6) who was treated consecutively for compressive damage of the optic nerves, hydrocephalus communicans and progressive spastic tetraparesis within 2 years. The clinical course of the patient is presented and the pathophysiologic mechanisms of disease progression in patients with Maroteaux-Lamy syndrome are discussed and reviewed.

Altered corneal stromal matrix organization is associated with mucopolysaccharidosis I, III and VI

The presence of cloudy corneas is a prominent feature of mucopolysaccharidosis (MPS) types I and VI, but not MPS IIIA or IIIB. The cause of corneal cloudiness in MPS I and VI is speculative. Transparency of the cornea is dependent on the uniform diameter and the regular spacing and arrangement of the collagen fibrils within the stroma. Alterations in the spacing of collagen fibrils in a variety of conditions including corneal edema, scars, and macular corneal dystrophy is clinically manifested as corneal opacity. The purpose of this study was to compare the structural organization of the stromal extracellular matrix of normal corneas with that of MPS corneas. The size and arrangement of collagen fibrils in cloudy corneas from patients with MPS I were examined. The alterations observed were an increased mean fibril diameter with a broader distribution in the MPS corneas. The MPS I corneas also had altered fibril spacing and more irregular packing compared with normal control corneas. The clear corneas of patients with MPS IIIA and IIIB also showed increases in mean fibril diameter and fibril spacing. However, there was less variation indicating more regularity than seen in MPS I. In addition, corneas from cat models of certain MPS were compared to the human corneas. Cats with MPS I and VI, as well as normal control cats, were examined. Structural alterations comparable to those seen in human MPS corneas were seen in MPS I and VI cats relative to normal clear corneas. The findings suggest that cloudy corneas in MPS I and VI are in part a consequence of structural alterations in the corneal stroma, including abnormal spacing, size, and arrangement of collagen fibrils.

Mild form of Maroteaux-Lamy syndrome: corneal histopathology and ultrastructure

PURPOSE

Maroteaux-Lamy syndrome is one of the mucopolysaccharidoses (MPSs) that is caused by the incomplete degradation and storage of dermatan sulfate.

METHODS

We describe a 49-year-old female patient with the mild form of the disease (MPS VI-B) who developed bilateral increasing corneal opacification and increased intraocular pressure after cervical-fusion surgery. After treatment of the increased intraocular pressure, she underwent a penetrating keratoplasty of her right eye.

RESULTS

The histopathologic and ultrastructural features of the corneal button were the accumulation of membrane-bound vacuoles containing fibrillogranular and lamellated material in keratocytes and endothelial cells and thinning of Descemet's membrane with excrescences.

CONCLUSION

Our review of the literature reveals only two prior histologic studies of corneas affected by MPS VI B.

Ocular abnormalities in the mucopolysaccharidoses after bone marrow transplantation. Longer follow-up

OBJECTIVE

The purpose of the study was to provide longer follow-up of ocular findings in patients with mucopolysaccharidoses (MPS) after bone marrow transplantation (BMT).

DESIGN

The study design was a retrospective 6-year cohort evaluation.

PARTICIPANTS

Twenty-three patients with MPS (19 with MPS type I-H, 3 with MPS type III, 1 with MPS type VI) were studied.

INTERVENTION

Bone marrow transplantation was performed.

MAIN OUTCOME MEASURES

The following outcome measures were considered: vision, slit-lamp biomicroscopic and funduscopic examinations, intraocular pressure, electroretinography (ERG), and retinoscopy.

RESULTS

Thirteen (81%) of 16 patients showed ERG improvement in the first year. However, all patients showed slowly progressive decline of the ERG over longer follow-up. Other ocular findings included optic atrophy (n = 7 patients), disc edema (n = 6 patients), strabismus (n = 6 patients), nystagmus (n = 6 patients), cataract (n = 3 eyes), keratoconjunctivitis sicca (n = 4 eyes), ocular hypertension (n = 2 eyes), and glaucoma (n = 2 eyes).

CONCLUSIONS

The MPS are rare and heterogeneous disorders characterized by progressive retinal degeneration and blindness. Ocular abnormalities can occur as a result of the disease or as a consequence of BMT. Successful BMT has been shown to improve systemic health, but this may not reflect continuing ocular status and retinal function. Despite early improvement in ERG function, longer follow-up suggests progressive retinal decline.

Allogeneic CD34 selected peripheral stem cell transplant for Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI): rapid haemopoietic and biochemical reconstitution

Severe Maroteaux-Lamy syndrome is usually fatal in teenage or early adult life. Until recently, allogeneic bone marrow transplantation was the only form of enzyme replacement. We report the first successful transplant using CD34 selected, mobilised allogeneic blood cells for an inborn error of metabolism. A busulphan, cyclophosphamide, melphalan and antithymocyte globulin conditioning regimen was used as myeloablative therapy. Allogeneic CD34 selected granulocyte colony-stimulating factor (G-CSF)-mobilised blood cells from a HLA-identical sibling were used for the transplant. Haemopoietic reconstitution occurred on day 10 post-transplant with normal N-acetylgalactosamine-4-sulphatase levels. Infectious and graft-versus-host disease (GVHD) complications were minimal. We suggest that CD34 selected, mobilised allogeneic blood cells are a safe form of enzyme replacement therapy in Maroteaux-Lamy syndrome and should be considered in other metabolic diseases where the benefits of haemopoietic transplantation are proven.

Maroteaux-Lamy syndrome associated with growth hormone deficiency

Growth retardation is a common feature of mucopolysaccharide storage disorders, mostly considered to be a consequence of skeletal changes, Maroteaux-Lamy disease is a subtype of mucopolysaccharidosis, demonstrating somatic changes and skeletal deformities. We present a case with Maroteaux-Lamy disease associated with growth hormone deficiency. Magnetic resonance imaging study revealed marked signal changes in white matter due to the storage in brain and empty sella appearance in sellar region. In the presence of empty sella syndrome, hypothalamic-pituitary dysfunction due to the storage material may have led to growth hormone deficiency in this patient. Therefore, we recommend patients with mucopolysaccharidosis, especially those who have growth retardation, to be evaluated by hormonal and radiological studies.

Mucopolysaccharidosis: MPS VI and associated delayed tooth eruption

Eight cases of mucopolysaccharidosis Type VI (Maroteaux-Lamy syndrome) are reviewed and two cases are presented in detail. Developmental dental anomalies including unerupted and impacted permanent teeth and associated hyperplastic tooth follicles are seen frequently in MPS patients. The surgical implications and management are discussed. All patients reviewed had significant cardiovalvular disease. It is essential for the primary medical provider to establish early basic dental care and evaluation for delayed eruption of primary and permanent dentition. This will probably minimize the possibility of infective endocarditis and allow for early treatment of impacted teeth.

Hydrocephalus and pseudotumour cerebri in the mucopolysaccharidoses

This paper reports two cases of cerebrospinal fluid circulation disorder in children with mucopolysaccharidosis. One patient developed pseudotumour cerebri and the other communicating hydrocephalus. It is suggested that both have a similar underlying abnormality of cerebrospinal fluid absorption with different modes of presentation.

Characterization of osteopenia in feline mucopolysaccharidosis VI and evaluation of bone marrow transplantation therapy

Studies on a feline model of MPS VI demonstrated a marked osteopenia in iliac crest bone samples from young adult animals with fewer, finer trabeculae. In the absence of significant differences in bone remodeling, this was considered due to defects in endochondral ossification and the formation of fewer trabeculae. Cell-level bone formation was normal despite the presence of vacuolated osteoblasts. Affected animals had vacuolated osteocytes in larger lacunae. Cats of the same age who had received a bone marrow transplant 12 months prior as young kittens, had significantly more trabecular bone with thicker trabeculae. The presence of smaller osteocyte lacunae in these animals as compared to their untreated MPS VI cats appeared to be a direct effect of bone marrow transplantation and a useful parameter to monitor its efficacy.

Hydrocephalus, lumbar canal stenosis and Maroteaux-Lamy syndrome (mucopolysaccharidosis type 6). Case report

A case of communicating hydrocephalus and lumbar canal stenosis in a child with mucopolysaccharidosis type 6 is reported. We review the literature and discuss the aetiology of communicating hydrocephalus in this condition.

Mitral stenosis in the Maroteaux-Lamy syndrome: a treatable cause of dyspnoea

The case is reported of a young woman with the Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI) who presented with rapidly progressive dyspnoea due to mitral stenosis. Mitral valve replacement was performed and the appearance of the valve was typical of mucopolysaccharide infiltration. Dyspnoea in patients with the Maroteaux-Lamy syndrome may be due primarily to cardiac valve involvement, and in this setting, valve surgery is safe and effective.

Acute infantile cardiomyopathy as a presenting feature of mucopolysaccharidosis VI

An infant with a diagnosis of acute infantile cardiomyopathy was subsequently shown to have mucopolysaccharidosis VI. The mucopolysaccharidoses should be included in the differential diagnosis of infantile cardiomyopathy.

Valvular heart disease in four patients with Maroteaux-Lamy syndrome

BACKGROUND

Maroteaux-Lamy syndrome is a lysosomal storage disease of mucopolysaccharide metabolism (MPS type VI) that may involve the mitral and aortic valves. Affected patients have other skeletal and oropharyngeal malformations that complicate anesthetic and surgical management.

METHODS AND RESULTS

The present report describes the clinical, echocardiographic, and pathological findings in four patients with Maroteaux-Lamy syndrome. Two of three siblings underwent successful double-valve replacement for aortic and mitral valve stenoses. The third sibling, whose aortic and mitral valves were thick and fibrotic, died from septicemia after hip surgery. A fourth, unrelated patient also had successful double-valve replacement.

CONCLUSIONS

Our experience emphasizes the potential difficulties in preoperative assessment and surgical treatment as well as the unique problems related to airway management in patients with this syndrome.

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) with hearing impairment and pupillary membrane remnants

A Japanese boy aged 13 months was referred to us because thickened ribs had been observed on a chest X-ray taken during a respiratory infection. mucopolysaccharidosis type VI (MPS VI) was diagnosed based on urinary glycosaminoglycan analysis and low activity of arylsulfatase B in peripheral leukocytes. He had mild pupillary membrane remnants, but no corneal opacities. The auditory brainstem response revealed moderate hearing impairment, which may have caused his subnormal DQ score of 85 at the age of 19 months. Although MPS VI is characterized by normal intellectual development with normal hearing in early infancy, it is important to examine for hearing loss, especially when an infant with this disease shows developmental delay.

Somatosensory and magnetic evoked potentials in a postoperative paraparetic patient: case report

Somatosensory evoked potential (SSEP) testing is increasingly being used to test for spinal cord injuries and to monitor spinal surgery to reduce the risk of paraplegia. It is a sensory test, but it is assumed that any process severe enough to affect the motor tracts will also affect the sensory tracts and, therefore, be identified. Increasingly, however, isolated motor-tract involvement has been reported. A new technique, magnetic coil stimulation of the cortex, directly monitors the motor tracts. We report a case where the SSEP was normal although the magnetic motor-evoked potential was abnormal, supporting the hypothesis that direct testing of motor tracts may be advantageous.

Myelopathy due to diffuse thickening of the cervical dura mater in Maroteaux-Lamy syndrome: report of a case

A rare case of diffuse thickening of the cervical dura mater leading to cord compression in Maroteaux-Lamy syndrome (mucopolysaccharidosis VI) is reported. Spinal computed tomographic scans after intrathecal metrizamide injection and magnetic resonance images are shown. This condition presents as cervical myelopathy. Early decompression can be beneficial for patients with this infrequent metabolic disorder.

Endocardial fibroelastosis in mucopolysaccharidosis type VI

This case report describes two siblings less than 1 year of age who presented severely ill with a dilated cardiomyopathy. Full blood examination in both cases revealed marked granularity of neutrophils suggestive of mucopolysaccharidosis type VI. There were no physical features of a mucopolysaccharidosis but biochemical evaluation confirmed mucopolysaccharidosis type VI in both children. Autopsy in one patient confirmed endocardial fibroelastosis and electron microscopy of fibroblasts in the myocardium showed distention with membrane-bound vacuoles, consistent with a mucopolysaccharidosis. These siblings developed endocardial fibroelastosis before other clinical manifestations of the mucopolysaccharidosis. Assessment for metabolic causes of a cardiomyopathy is important, as cardiac disease may be the initial manifestation of a metabolic disease.

Otosclerosis and mucopolysaccharidosis

By means of a literature review, clinical observations and temporal bone histopathology in the Hunter syndrome, we could show a reason for otosclerosis in childhood, a very rare observation. Therefore we do not believe that the presence of otosclerotic foci in temporal bones is mere coincidence in MPS II. It seems there is a causal connection between the generalized metabolic disorder and otosclerosis on the basis of enzyme deficiency.

Mental retardation in a patient with Maroteaux-Lamy

An 8-year-old boy with Hurler-like traits including severe mental retardation excreted in his urine a pathognomonic amount of dermatan sulfate. Less than 10% residual activity of arylsulfatase B was found in his leucocytes and fibroblasts. Hurler fibroblasts corrected an abnormally high 35SO4-incorporation into acid mucopolysaccharides (MPS) in cultured fibroblasts, whereas Maroteaux-Lamy fibroblasts did not. The patient thus has a rare combination of Maroteaux-Lamy and severe mental retardation.