Littérature scientifique sur le sujet « Mucopolysaccaridosis type I »

Introduction The accumulation of glycosaminoglycan (GAGs) in the tissues in Mucopolysaccharidoses (MPS) can lead to skeletal anomalies (DYSOSTOSIS MULTIPLEX) and to soft tissue impairments (neural or medullar compression, joint stiffness, tenosynovitis). Here is a review of orthopedic issues frequently encountered in patients with MPS. Material and methods Surgery may be justified at different age and according to the type of MPS. Different surgical approaches and their indications are exposed in the article. Results The article exposes indications and techniques for orthopedic issues in MPS children: cervical stenosis, cervical instability, kyphosis, hip dysplasia and hip dislocation, genu valgum. Conclusion Various musculoskeletal anomalies can be found in patients with mucopolysaccharidoses. Neurological impairments are frequently seen due to cervical stenosis or instability and should be early detected with regular MRI of the cervical spine. Well-codified management should lead to favorable functional results and maintain functional and walking abilities.

Abstract Objectives Lysosomal storage diseases (LSD) constitute an important group of metabolic diseases, consisting of approximately 60 disorders. In some types of lysosomal diseases, enzyme replacement therapy (ERT) is administered intravenously in weekly or biweekly doses. Unfortunately, scheduled ERT during COVID-19 was disrupted. We considered the possibility of adverse outcomes caused by the disruption in the treatment of patients with lysosomal storage disorders. Methods During the COVID-19 pandemic, we conducted a questionnaire that was delivered via Internet to assess how this vulnerable patient group was affected by the pandemic in terms of their access to treatment and their disease-related symptoms. Results The questionnaire was filled out by 75 patients. There were 35 patients whose treatment dose was missed because of COVID-19. The most common reason for skipping treatment was not wanting to go to the hospital for fear of contracting COVID-19. These 35 patients missed a median of four doses of ERT (range: 1–16 dosages). Twenty-one patients (60%) claimed that they were affected physically by not taking ERT (20 mucopolysaccaridoses, 1 Fabry disease), whereas 14 (40%) did not. Conclusions Interruption of ERT during the COVID-19 pandemic may have significant consequences. It may be beneficial to switch to home treatment or reserve dedicated facilities. With proper planning and management, the treatment disruptions of this particular group can be avoided.

Mucopolysaccharidosis type IIIA (MPS IIIA) is caused by mutations in the N-sulphoglucosamine sulphohydrolase (SGSH) gene, leading to cellular accumulation of heparan sulphate and progressive neurodegeneration in patients. One of the proposed treatment methods is haematopoietic stem cell (HSC) gene therapy, which should result in an excess of SGSH produced in the peripheral organs and brain. The pre-clinical feasibility of this approach was demonstrated by our group in a mouse model of MPS IIIA. However, the overall efficiency of this method was limited and a number of approaches to solving these issues were addressed in this project in order to bring this therapy closer to clinical application. Our first aim was to optimise transduction of HSCs using cytokines, bovine serum albumin (BSA), and chemicals, such as MG132, genistein and valproic acid. Addition of BSA with cytokines improved cell viability, addition of MG132/ BSA/ cytokines improved transduction, but also caused cellular toxicity, while addition of genistein was inefficient. Addition of valproic acid with cytokines resulted in increased number of colony forming units. Next, we generated clinically applicable third generation pCCL lentiviral vector backbones with the eGFP reporter gene driven by one of ubiquitous hPGK or myeloid specific hCD11b and hCD18 internal human promoters, and optimised production of lentiviral vectors to increase titre and reduce production cost. These lentiviral vectors were used to transduce lineage depleted HSCs and transplanted into WT mice. Full chimerism and over 80% transduction were achieved with an average of 5 vector copy numbers/ cell. The hCD11b promoter resulted in the highest eGFP expression in monocytes and B cells in blood, but was weaker than the hPGK in T cells. The hCD18 promoter was more monocyte-specific but weak. Significant numbers of GFP-positive microglial cells were present in the brain from all groups, with an average of 25% transduced CD11b-positive cells in perfused mice. We subsequently codon-optimised (CO) the SGSH gene significantly improving enzyme activity, and transduced lineage depleted WT cells with one of hCD18.SGSH-CO, hCD11b.SGSH-CO, or hPGK.SGSH-CO lentiviral vectors, or MPS IIIA cells with either hCD11b.SGSH-CO or hPGK.SGSH-CO lentiviral vectors. These transduced cells were transplanted into MPS IIIA mice and outcomes were measured 6 months later. Only treatment with the hCD11b.SGSH-CO-LV transduced WT or MPS IIIA HSCs corrected abnormal behaviour of MPS IIIA mice. However, all treatments resulted in complete GAG storage clearance in the periphery and brain, and significantly elevated enzyme activity in the brain, liver and spleen to 7-11%, 60-75%, and 170-250% of WT enzyme activity respectively. A fine threshold of over 8.6% brain enzyme activity appeared to be required for behavioural correction in MPS IIIA mice. Further assessment of treated mice for the amount of secondary storage, HS sulphation patterning, neuroinflammation and longevity are still required for complete therapeutic assessment. However, it appears that neurological correction of the MPS IIIA mouse using MPS IIIA cells is feasible using a clinically-relevant pCCL vector with the hCD11b promoter and the codon-optimised SGSH gene.

Mucopolysaccharidosis type I (MPS-IH or Hurler syndrome) is a rare lysosomal storage disease caused by mutations in the IDUA gene, resulting in the deficiency of alpha-L-iduronidase (IDUA) enzyme activity with a consequent intracellular accumulation of glycosaminoglycans (GAGs). Among a broad spectrum of clinical manifestations, MPS-IH is characterized by a range of skeletal abnormalities known as dysostosis multiplex. To date, the skeletal pathogenesis of the MPSs has been assumed to be directly related to the progressive storage of GAGs. It is now clear that more complex cellular and molecular mechanisms underlie the patient clinical symptoms. Therefore, an appropriate humanized in vitro model is highly recommended to highlight these mechanisms. Compared to mesenchymal stromal cells (MSCs), induced pluripotent stem cells (iPSCs) represent a useful tool to achieve this purpose, due to their high proliferation capability in culture and, mostly, to their ability to mimic development. Thus, they demonstrate great potential for investigating the osteogenic differentiation process. In this study, we generated MPS-IH patient-specific iPS cells (MPS-IH iPSCs) which maintained the genetic mutation in the IDUA gene and, as a consequence, reduced IDUA enzyme activity and GAGs intracellular accumulation. In order to assess if the osteogenic differentiation phenotype is already compromised in MPS-IH iPSCs cell, we focused on their bone differentiation capability. Thus, we developed an osteogenic differentiation protocol through the generation of mesenchymal stromal cells from iPSC (hereafter named MSCs-like cells). We designed a robust, multistep differentiation method to isolate MSCs-like cells, both from wild-type iPSCs (WT-iPSCs) and MPS-IH iPSCs. The process included: embryoid body (EB) formation, cell outgrowth from EBs, monolayer culture of sprouted cells from EBs, and a serial of passages in culture until they reached a fibroblast-like morphology and the full expression of mesenchymal surface markers. Firstly, we characterized WT and patient derived-MSCs-like cells in terms of morphology, phenotype, proliferation kinetics and differentiation capacity in mesodermal tissues. WT and patient derived-MSCs-like cells showed the capacity to differentiate in adipocytes, as confirmed by Oil Red O staining. Moreover, MSCs-like cells derived-chondrogenic pellets exhibited a spherical, compact morphology. Histological analysis revealed an initial chondrogenic differentiation, as confirmed by q-RT-PCR for key early chondrogenic markers, such as SOX9 and COLII. Subsequently, we developed an osteogenic differentiation protocol for the obtained MSC-like cells. In order to verify if the differentiation process was accomplished, we performed Alizarin Red staining and quantified the hydroxyapatite production by colorimetric detection at 405 nm both on WT and MPS-IH iPSCs-derived osteoblasts. At the same time, we examined the expression for key osteogenic markers, such as OPN, RUNX2 OTC, OTN, ALP and COL 1A2, through q-RT-PCR. Recently, our group isolated MSCs from bone marrow (BM-MSCs) of both healthy donors and MPS-IH patients, studying a possible involvement of MSCs in the skeletal abnormalities affecting Hurler patients. We previously observed the ability of WT, MPS-IH BM-MSCs and MSCs-derived osteoblasts to stimulate osteoclastogenesis in vitro by measuring the molecular levels of receptor activator of nuclear factor-Kb ligand (RANKL) and osteoprotegerin (OPG), two key partners of the system directly regulating osteoclast differentiation. MPS-IH MSCs and osteoblasts derived from MPS-IH MSCs, expressed a higher level of RANKL compared to HD-MSCs and osteoblasts. OPG level, instead, was similar. In the present study, the osteogenic differentiation protocol developed allowed us to assess if this altered phenotype is already evident in both MSCs-like cells MSCs-like derived osteoblasts, by evaluating the OPG and RANKL expression levels.