Glycosaminoglycan Metabolism Research Articles

Urinary Glycosaminoglycan Estimation as a Routine Clinical Service.

Mucopolysaccharidoses, a group of inherited disorders are associated with defects in glycosaminoglycan metabolism. Thus, assessment of urinary glycosaminoglycan is used as a screening test for mucopolysaccharidoses. The detection methods range from qualitative spot tests to quantification using metachromatic dyes. In our laboratory we optimized a spectrophotometric quantitative method using a metachromatic dye, dimethylmethylene blue. Heparan sulfate was used for quantification. The glycosaminoglycan-dye complex showed a marked shift in color with increase in concentration. The color complex was quantified at 520nm. The method was linear from 10-89mg/L. An age matched normal range was obtained in 177 healthy individuals, grouped in 8 different age groups from neonates to adults. Urinary glycosaminoglycan concentration varied distinctly amongst the study population wherein the lowest range in healthy neonates was more than 3 times the upper limit of healthy adults. Urine samples from 10 patients with mucopolysaccharidoses were also included in the study for clinical validation. The method qualified both analytical and clinical validation and was found to be simple, robust and ideal to be offered as a screening test for mucopplysaccharidoses in a routine clinical chemistry laboratory.

Blood cells transcriptomics as source of potential biomarkers of articular health improvement: effects of oral intake of a rooster combs extract rich in hyaluronic acid

The aim of the study was to explore peripheral blood gene expression as a source of biomarkers of joint health improvement related to glycosaminoglycan (GAG) intake in humans. Healthy individuals with joint discomfort were enrolled in a randomized, double-blind, placebo-controlled intervention study in humans. Subjects ate control yoghurt or yoghurt supplemented with a recently authorized novel food in Europe containing hyaluronic acid (65%) from rooster comb (Mobilee™ as commercial name) for 90days. Effects on functional quality-of-life parameters related to joint health were assessed. Whole-genome microarray analysis of peripheral blood samples from a subset of 20 subjects (10 placebo and 10 supplemented) collected pre- and post-intervention was performed. Mobilee™ supplementation reduced articular pain intensity and synovial effusion and improved knee muscular strength indicators as compared to placebo. About 157 coding genes were differentially expressed in blood cells between supplemented and placebo groups post-intervention, but not pre-intervention (p<0.05; fold change ≥1.2). Among them, a reduced gene expression of glucuronidase-beta (GUSB), matrix metallopeptidase 23B (MMP23B), xylosyltransferase II (XYLT2), and heparan sulfate 6-O-sulfotransferase 1 (HS6ST1) was found in the supplemented group. Correlation analysis indicated a direct relationship between blood cell gene expression of MMP23B, involved in the breakdown of the extracellular matrix, and pain intensity, and an inverse relationship between blood cell gene expression of HS6ST1, responsible for 6-O-sulfation of heparan sulfate, and indicators of knee muscular strength. Expression levels of specific genes in blood cells, in particular genes related to GAG metabolism and extracellular matrix dynamics, are potential biomarkers of beneficial effects on articular health.

Systems toxicology approaches enable mechanistic comparison of spontaneous and cigarette smoke-related lung tumor development in the A/J mouse model.

The A/J mouse is highly susceptible to lung tumor induction and has been widely used as a screening model in carcinogenicity testing and chemoprevention studies. However, the A/J mouse model has several disadvantages. Most notably, it develops lung tumors spontaneously. Moreover, there is a considerable gap in our understanding of the underlying mechanisms of pulmonary chemical carcinogenesis in the A/J mouse. Therefore, we examined the differences between spontaneous and cigarette smoke-related lung tumors in the A/J mouse model using mRNA and microRNA (miRNA) profiling. Male A/J mice were exposed whole-body to mainstream cigarette smoke (MS) for 18 months. Gene expression interaction term analysis of lung tumors and surrounding non-tumorous parenchyma samples from animals that were exposed to either 300 mg/m3 MS or sham-exposed to fresh air indicated significant differential expression of 296 genes. Ingenuity Pathway Analysis® (IPA®) indicated an overall suppression of the humoral immune response, which was accompanied by a disruption of sphingolipid and glycosaminoglycan metabolism and a deregulation of potentially oncogenic miRNA in tumors of MS-exposed A/J mice. Thus, we propose that MS exposure leads to severe perturbations in pathways essential for tumor recognition by the immune system, thereby potentiating the ability of tumor cells to escape from immune surveillance. Further, exposure to MS appeared to affect expression of miRNA, which have previously been implicated in carcinogenesis and are thought to contribute to tumor progression. Finally, we identified a 50-gene expression signature and show its utility in distinguishing between cigarette smoke-related and spontaneous lung tumors.

Changes in the metabolism of chondroitin sulfate glycosaminoglycans in articular cartilage from patients with Kashin–Beck disease

To identify changes in the expression patterns of enzymes involved in chondroitin sulfate (CS) glycosaminoglycan (GAG) metabolism in articular cartilage proteoglycan (PG) isolated from adolescent patients with Kashin-Beck disease (KBD). Samples of articular cartilage were divided into two groups: Control samples (from five normal children), and KBD samples (from five KBD children) aged 3-12 years old. The morphology and pathology of hand joint cartilage were examined by histochemical staining. The localization and expression patterns of enzymes involved in CS GAG metabolism (i.e., PAPS synthetase 2 (PAPSS2), PAPS transporter 1 (PAPST1), Carbohydrate (N-acetylgalactosamine 4-sulfate 6-O) sulfotransferases 15 (CHST15), Arylsulfatase B (ARSB) and N-acetylgalactosamine-6-sulfate sulfatase (GALNS)) were performed using immuno-histochemical analyses. Positive immunostaining in articular cartilage was semi-quantified. Reduced aggrecan staining was observed in KBD samples compared with the control samples. The percentages of positive staining for the anabolic enzymes PAPSS2, PAPST1 and CHST15 in the upper and middle zones of KBD samples were significantly lower than that found in the Controls. In contrast, the percentages of positive staining in KBD samples for the catabolic enzymes ARSB and GALNS were significantly higher than the control samples. However, the staining for all of these GAG metabolism enzymes were hardly observed in the deep zones of KBD cartilage, suggesting that significant cell death and necrosis had occurred in this region. Our results indicate that alterations of enzymes involved in articular cartilage CS GAG metabolism on PGs in the articular cartilage play an important role in the onset and pathogenesis of KBD in adolescent children.

Genistein increases glycosaminoglycan levels in mucopolysaccharidosis type I cell models

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder characterized by diminished degradation of the glycosaminoglycans (GAGs) heparan sulfate and dermatan sulfate, which results in the accumulation of these GAGs and subsequent cellular dysfunction. Patients present with a variety of symptoms, including severe skeletal disease. Genistein has been shown previously to inhibit GAG synthesis in MPS fibroblasts, presumably through inhibition of tyrosine kinase activity of the epidermal growth factor receptor (EGFR). To determine the potentials of genistein for the treatment of skeletal disease, MPS I fibroblasts were induced into chondrocytes and osteoblasts and treated with genistein. Surprisingly, whereas tyrosine phosphorylation levels (as a measure for tyrosine kinase inhibition) were decreased in all treated cell lines, there was a 1.3 and 1.6 fold increase in GAG levels in MPS I chondrocytes and fibroblast, respectively (p < 0.05). Sulfate incorporation in treated MPS I fibroblasts was 2.6 fold increased (p < 0.05), indicating increased GAG synthesis despite tyrosine kinase inhibition. This suggests that GAG synthesis is not exclusively regulated through the tyrosine kinase activity of the EGFR. We hypothesize that the differences in outcomes between studies on the effect of genistein in MPS are caused by the different effects of genistein on different growth factor signaling pathways, which regulate GAG synthesis. More studies are needed to elucidate the precise signaling pathways which are affected by genistein and alter GAG metabolism in order to evaluate the therapeutic potential of genistein for MPS patients.

Role of the endothelial glycocalyx in kidney disease and vascular dysfunction

BackgroundAlbuminuria, an early marker of kidney disease, is strongly and independently associated with adverse cardiovascular outcomes, including heart attacks and strokes. Nonetheless, the mechanisms linking albuminuria and adverse cardiovascular events remain unclear. The endothelial glycocalyx, a friable but protective lining of all blood vessels, is damaged in both atherosclerosis and kidney disease. We examined whether factors in the plasma of patients with kidney disease could damage the endothelial glycocalyx, and sought underlying mechanisms. MethodsMetabolic labelling of glycosaminoglycans (GAGs) was achieved by culturing human glomerular endothelial cells in media containing 20 μCi/mL D-[3H3] glucosamine for 24 h. Monolayers were washed and subsequently exposed either to conditioned serum free media containing 10% plasma from patients with either heavy albuminuria (from an intrinsic renal disease) or from healthy controls for 24h, or to 100 μM hydrogen peroxide or vehicle for 4 h. The supernatant was then collected and applied to a di-ethyl-amino-ethyl fast flow column connected to a fast protein liquid chromatography system. Samples were applied to the column at 1 mL/min and subsequently merged with column matrix for 15 min. Bound proteoglycans were eluted with 7M urea (pH 6) and collected in 1 mL fractions. All fractions were quantified by liquid scintillation counting. FindingsExposure of glomerular endothelial cells to plasma from three patients with albuminuria resulted in reduced levels of GAGs into the media (control plasma 112 514 disintegrations per min (DPM) [SE 6153], albuminuric plasma 74 743 DPM [9607]; p<0·05 unpaired t test), indicating altered endothelial cell GAG metabolism that might represent decreased turnover. Because oxidative stress is regarded as a key mediator of endothelial dysfunction in kidney disease, we generated reactive oxygen species by exposing cells to hydrogen peroxide. This exposure resulted in a different pattern of GAG turnover: shedding of radiolabelled GAGs into the media was increased (vehicle 1302 [684] DPM D-[3H3] glucosamine-labelled heparan sulphate GAG, hydrogen peroxide 25 053 [6635] DPM D-[3H3] glucosamine-labelled heparan sulphate GAG; p<0·005 unpaired t test). InterpretationDamage to the endothelial glycocalyx in response to factors in albuminuric plasma provides a novel concept in understanding endothelial dysfunction in disease states. This work provides evidence that the albuminuric state itself might lead to systemic alterations in endothelial cell function, although our preliminary studies indicate that reactive oxygen species are unlikely to be involved in these changes. We are now seeking alternative pathways underlying the effects of albuminuric plasma on the endothelial glycocalyx, assessing whether the endothelial glycocalyx is damaged in blood vessels in situ in patients with kidney disease, and examining whether the endothelial glycocalyx can be restored (and endothelial cell function improved) by manipulating these pathways. Our long-term goal is to manipulate endothelial glycocalyx regulation to develop an entirely new class of treatments for vasculoprotection in kidney disease and other conditions. FundingNational Institute for Health Research.

Evaluation of the metabolism of glycosaminoglycans in patients with interstitial cystis

Painful bladder syndrome/interstitial cystitis (PBS/IC) pathogenesis is not fully known, but evidence shows that glycosaminoglycans (GAG) of bladder urothelium can participate in its genesis. The loss of these compounds facilitates the contact of urine compounds with deeper portions of bladder wall triggering an inflammatory process. We investigated GAG in urine and tissue of PBS/IC and pure stress urinary incontinence (SUI) patients to better understand its metabolism. Tissue and urine of 11 patients with PBS/IC according to NIDDK criteria were compared to 11 SUI patients. Tissue samples were analyzed by histological, immunohistochemistry and immunofluorescence methods. Statistical analysis were performed using t Student test and Anova, considering significant when p < 0.05. PBS/IC patients had lower concentration of GAG in urine when compared to SUI (respectively 0.45 ± 0.11 x 0.62 ± 0.13 mg/mg creatinine, p < 0.05). However, there was no reduction of the content of GAG in the urothelium of both groups. Immunofluorescence showed that PBS/IC patients had a stronger staining of TGF-beta, decorin (a proteoglycan of chondroitin/dermatan sulfate), fibronectin and hyaluronic acid. the results suggest that GAG may be related to the ongoing process of inflammation and remodeling of the dysfunctional urothelium that is present in the PBS/IC.

Sclero-Resistance, Sclero-Sensibility and Sclero-Sensitization: The Role of the Tunica Adventitia in Sclerotherapy

Aim The aim of this study was to assess the importance of the tunica adventitia in sclerotherapy, measuring sclero-resistance, sclero-sensitivity and sclero-sensitization parameters. Materials and Methods 900 cases of Great Saphenous Vein (GSV) varicosity treated with Sigg-method sclerotherapy were examined for sclero-resistance as indicated by an ultrasound sclero-resistance marker (SRM+). Sclero-sensitivity was assessed by contact thermography in 356 cases of GSV varicosity with collagen alterations treated with Sigg sclerotherapy. Sclero-sensitization and treatment efficacy were assessed in 50 cases of non-reflux related telangiectasias recurring after a first course of foam microsclerotherapy and retreated with a second sclerotherapy regimen administered together with intradermal glycosaminoglycans (GAG). Results Indicative of incomplete parietal fibrosis, the ultrasound marker SRM+ was most frequently found among patients with recurrence. The degree of sclero-sensibility was found to be inversely proportional to proteoglycan concentrations in the Ground Substance (GS), which in turn was seen to present in differing amounts in the various connective tissue diseases. Sclerotherapy combined with the administration of GAGs proved significantly effective in the treatment of recurrent telangiectasias, indicating GAG sclero-sensitizing properties Conclusions The efficacy of sclerotherapy depends on eliciting a regular fibrotic reaction starting from the connective tissue of the adventitia, which is modulated by ground substance GAG metabolism.

Collagen and Glycosaminoglycan Profiles in the Canine Cervix during Different Stages of the Estrous Cycle and in Open- and Closed-Cervix Pyometra

ABSTRACTThe extracellular matrix of the cervix that comprises collagen, elastin, proteoglycans and glycosaminoglycans (GAGs) is thought to have an essential role in cervical relaxation. This study investigated the proportion of collagen and smooth muscle as well as the GAGs in cervices obtained from healthy bitches at different stages of the estrous cycle and bitches with open- and closed-cervix pyometra. Cervices were collected after ovariohysterectomy. The proportion of collagen to smooth muscle was determined using Masson’s trichrome staining. Alcian blue staining was used to evaluate the relative distribution of cervical GAGs. The proportion of cervical collagen relative to smooth muscle was higher at estrus compared to anestrus (P≤0.05). It was also higher (P≤0.05) in bitches with open- compared to those with closed-cervix pyometra. Overall, hyaluronan (HA) was the predominant GAG in the canine cervix. In the luminal epithelium, the staining intensity for HA was stronger in estrus than in anestrus (P≤0.05), but not in diestrus (P>0.05). On the contrary, the intensity for the combined keratan sulfate (KS) and heparan sulfate (HS) was stronger in anestrus than in estrus and diestrus (P≤0.05). In bitches with pyometra, the staining intensity of the stroma for KS and HS was weaker in open- compared to closed-cervix pyometra (P≤0.05). Collectively, the different profiles of collagen and GAG suggest that the metabolism of both collagen and GAGs in the canine cervix is associated with hormonal statuses during the estrous cycle and cervical patency of bitches with pathological uterine conditions, such as pyometra.

Assessment of respiratory involvement in children with mucoplysaccharidosis using pulmonary function tests

BackgroundMucopolysaccharidosis (MPS) are classified into seven clinical types based on eleven known lysosomal enzyme deficiencies of glycosaminoglycan (GAG) metabolism. Respiratory involvement seen in most MPS types includes recurrent respiratory infections, upper and lower airway obstruction, tracheomalacia, restrictive lung disease, and sleep disturbances. Aim of the studyTo delineate the pattern of respiratory compromise and pulmonary function abnormalities in MPS patients. MethodsThis is a cross section observational study conducted on 30 patients recruited from the Neurometabolic Clinic, Children’s Hospital, Cairo University over a period of 18months. All patients were screened first by the quantitative determination of GAGs in urine, and diagnosis was confirmed by unidimensional electrophoresis for GAGs in urine and/or specific enzymatic assay in blood leucocytes. Infant pulmonary functions (IPFT) were done in twenty-two patients (<3years of age), while 8 cases performed impulse oscillometry (IOS) test (3–6years of age). ResultsAges at diagnosis ranged from 1 to 9years with a median of 2.3years. Male to female ratio was 4:1. Consanguinity was observed in 53.3% whereas similar family condition was present in 40% of cases. Lumbar kyphosis was detected in 60% of cases, while scoliosis was detected in 46.7%. Results of pulmonary functions were mainly obstructive in 20 (66.6%) cases; however, combined obstructive and restrictive were detected in only 6 (20%) of cases. Data showed no association between the presence of scoliosis or the presence of organomegaly and the pattern of pulmonary function abnormalities. ConclusionsEvaluation and follow up of patients with MPS using pulmonary function tests are essential to detect early involvement of respiratory system and hence start treatment for respiratory complications early in the course of the disease.

Glycosaminoglycan metabolism defects and atherosclerosis: frequent association of endothelial dysfunction in patients with Mucopolysaccharidosis

Cardiovascular lesions, including coronary artery stenosis, are frequently associated and can cause sudden death in patients with genetic defects of glycosaminoglycan (GAG) metabolism. Early diagnosis of coronary artery lesions is difficult, although potentially lifesaving. Histopathological similarities between atherosclerotic changes in adults and in patients with genetic GAG metabolism defects have been known. Atherosclerosis is the result of a complex process involving metabolism of GAGs and proteoglycans preceded by endothelial dysfunction as a key event. Decreased nitric oxide (NO) bioavailability is considered the hallmark of endothelial dysfunction. Reduced NO synthase (NOS) has been reported in atherosclerotic arteries. Impairment in reactive hyperemia-digital peripheral arterial tonometry (RH-PAT) with EndoPAT has been validated to correlate coronary microvascular function in patients with atherosclerosis. RH-PAT is thought to reflect endothelial NO production. Immunohistological staining of endothelial NOS was performed in the stenotic lesions in the coronary artery of a 3-year-old patient with Mucopolysaccharidosis-I, showing decreased activities. This prompted a study to measure endothelial function in patients with GAG metabolism defects for early diagnosis of endothelial dysfunction in the coronary arteries as an early sign of coronary artery changes. Evaluation by RH-PAT in 30 patients with variable genetic defects in GAG metabolism revealed significantly decreased Reactive Hyperemia Indexes compared with 12 controls. Evaluation of endothelial function with RH-PAT in patients with GAG metabolism defects may detect coronary artery lesions that can be underdiagnosed by the other measures such as coronary angiography. Use of this method may prove vital in the management of patients with GAG metabolism defects.

Human milk glycosaminoglycans: the state of the art and future perspectives

Recently, a complete characterization and detailed evaluation of the glycosaminoglycans of human milk were performed. The total glycosaminoglycans content in milk from healthy mothers having delivered term or preterm newborns showed a constant pattern which was essentially composed of two main polysaccharides: chondroitin sulfate (60-70%) and heparin (30-40%). Moreover, considerable variations of glycosaminoglycans concentration were found during the first month of lactation, the highest values being present in colostrum compared to mature milk. Metabolism and potential biological functions of human milk glycosaminoglycans are hypothesized and future studies are encouraged.

Hunter syndrome presenting as heart failure: A case report

Introduction: Hunter syndrome (Mucopolysaccharidosis type II, MPS II) is a genetic disorder associated with deficiency of lysosomal enzyme iduronate­2­sulfatase and impairment of glycosaminoglycans (GAGs) metabolism. Hunter syndrome is well described in medical literature but less is known about heart failure. We are presenting a rare case of Hunter­syndrome with heart failure. Case Report: A 17­year­old boy presented to emergency department with chief complaint of dyspnea on exertion for last seven days. He also had history of progressive abdominal swelling since five years of age. On examination, he was tachypneic with raised jugular venous pressure and bilateral pitting pedal edema. His head was dolicocephalic in shape with coarse facial features. His abdomen was distended with hepatosplenomegaly and an umbilical hernia. He has one younger brother with similar clinical profile and one normal younger sister. Suspecting mucopolysaccharidosis, we performed a skeletal survey. A lateral X­ray of the skull showed an enlarged and J­shaped sella turcica. Patient’s and his brother’s enzyme assays for iduronate­2­sulfatase were markedly low. Based on the clinicoradiological and enzyme assay diagnosis of Hunter syndrome (MPS II) was made. Conclusion: Various clinical and radiological features are typical of MPS II. A detailed clinical evaluation and radiological investigations help in diagnosis of MPS II. The enzyme assay is required to confirm the diagnosis.

Otras enfermedades metabólicas

Wilson disease is an autosomal recessive defect due to an impairment cellular cooper metabolism, leading to the accumulation of copper in the liver and other tissues. Clinical manifestations consists of liver failure and neurophysichiatrics symptoms, although hematologic and renal impairment is also very frecuent. The diagnosis can be made with an elevated 24 hours urinary cooper excretion, but the gold standar method is liver biopsy. Treatment consists of administration of potent chelators.Mucopolysaccharidoses disease is caused by the impairment or deficiency of enzymes required for the metabolism of glycosaminoglycans. These condition leads to accumulation of metabolites in the lysosomes, resulting in cellular dysfunction and clinical abnormalities (organomegaly, coarse facial features, neurologic symptoms) Diagnosis is made by meassuring the concentration of glycosaminoglycans in urine and enzyme analysis. There are specific therapies, such as hematopoietic stem cell transplantation or enzyme replacement.Sphingomyelin-cholesterol lipidosis is disorder cause by deficiency of the enzyme that metabolize sphingomyelin. The classic clinical manifestations are: neurologic symptoms and organomegaly. Diagnosis is made by is confirmed by fibroblast cell culture enzyme activity analysis. Treatment: enzyme replacement if possible.

Neutral Sphingomyelinase 2 Deficiency Increases Hyaluronan Synthesis by Up-regulation of Hyaluronan Synthase 2 through Decreased Ceramide Production and Activation of Akt

Fibroblasts from the fro/fro mouse, with a deletion in the Smpd3 gene coding for the active site of neutral sphingomyelinase 2 (NSMase2), secreted increased amounts of hyaluronan (HA). This was reversed by transfection with the Smpd3 gene, suggesting a connection between sphingolipid and glycosaminoglycan metabolism. The deficiency of NSMase2 resulted in storage of sphingomyelin (SM) and cholesterol with a 50% reduction in ceramides (Cer). RT-PCR and Western blot analysis showed that increased HA secretion resulted from increased hyaluronan synthase 2 (HAS2) activity localized to sphingolipid-enriched lipid rafts. Although cholesterol levels were also elevated in lipid rafts from mouse fibroblasts deficient in lysosomal acid SMase activity (deletion of the Smpd1(-/-) gene), there was no increase in HA secretion. We then showed that in fro/fro fibroblasts, the reduced ceramide was associated with decreased phosphorylation of protein phosphatase 2A (PP2A) and increased phosphorylation of its substrate Akt-p, together with PI3K, PDK1, mTOR (mammalian target of rapamycin), and p70S6K, although PTEN was unaffected. Exogenous ceramide, as well as inhibitors of Akt (Akt inhibitor VIII), PI 3-kinase (LY294002 and wortmannin), and mTOR (rapamycin) reduced secretion of HA, whereas the NSMase2 inhibitor GW4869 increased HA synthesis and secretion. We propose that NSMase2/Cer are the key mediators of the regulation of HA synthesis, via microdomains and the Akt/mTOR pathway.

The role of glycosaminoglycans and proteoglycans in atherosclerosis

Numerous studies point out to the role of glycosaminoglycans (GAG) and proteoglycans (PG) in the pathogenesis of atherosclerosis. Both GAG and PG take part in the formation of tunica intima and tunica media, contribute to the neointima formation, and can be found in the glycocalix layer. These molecules influence many properties of blood vessels, such as permeability, viscoelasticity, hemostasis, lipid metabolism, and extracellular matrix organization. The PG from atherosclerotic arteries had higher binding affinity for LDL, which suggests that alterations in the vascular PG contents predispose to atherosclerosis development. Atherogenic LP retained in the intima in association with GAG/PG, undergo several modifications, such as the oxidation or aggregation. LDL exposed to CS PG is more susceptible to such modification, which favours uptake by the macrophages. Moreover, oxy-LDL stimulated SMC to synthesize longer chains GAG and enhanced LDL binding properties. For this reason GAG structure and metabolism are the potential targets of the therapeutic investigation.

Fell-Muir Lecture: chondroitin sulphate glycosaminoglycans: fun for some and confusion for others.

This review emphasizes the importance of glycobiology in nature and aims to highlight, simplify and summarize the multiple functions and structural complexities of the different oligosaccharide combinatorial domains that are found in chondroitin sulphate/dermatan sulphate (CS/DS) glycosaminoglycan (GAG) chains. For example, there are 1008 different pentasaccharide sequences possible within CS, DS or CS/DS hybrid GAG chains. These combinatorial possibilities provide numerous potential ligand-binding domains that are important for cell and extracellular matrix interactions as well as specific associations with cytokines, chemokines, morphogens and growth factors that regulate cellular differentiation and proliferation during tissue development, for example, morphogen gradient establishment. The review provides some details of the large and diverse number of different enzymes that are involved in CS/DS biosynthesis and attempts to explain how differences in their expression patterns in different cell types can lead to subtle but important differences in the GAG metabolism that influence cellular proliferation and differentiation in development as well as regeneration and repair in disease. Our laboratory was the first to generate and characterize monoclonal antibodies (mAb) that very specifically recognize different ‘native’ sulphation motif/epitopes in CS/DS GAG chains. These monoclonal antibodies have been used to identify very specific spatio-temporal expression patterns of CS/DS sulphation motifs that occur during tissue and organ development (in particular their association with stem/progenitor cell niches) and also their recapitulated expression in adult tissues with the onset of degenerative joint diseases. In summary, diversity in CS/DS sulphation motif expression is a very important necessity for animal life as we know it.

Clinical manifestation of Hurler syndrome in a 7 year old child

Mucopolysaccharidosis type I (MPS I H, Hurler syndrome) is a rare autosomal recessive inborn deficiency in the metabolism of glycosaminoglycans (GAGs) heparan sulfate and dermatan sulfate, resulting from deficiency of Alpha-L-iduronidase enzyme. This condition is characterized by accumulation of incompletely degraded glycosaminoglycans into various organs of body, which leads to impairment of organs and body functions. Such children appear nearly normal at birth; however, if left untreated, show a progressive mental and physical deterioration leading to death due to cardiorespiratory failure before the second decade of life. Pedodontists have a role for early diagnosis, rendering corrective and preventive treatment to the developing dentition, and referring the patient to the concerned specialities. An interesting case of a seven year old boy with a combination of skeletal, neurological, ophthalmologic, oro-dental and radiological findings of this diverse and devastating clinical entity with MPS I-(Hurler syndrome) has been presented here in this case report.

Valve surgery in a mucopolysaccharidosis type I patient: early prosthetic valve endocarditis

Mucopolysaccharidosis (MPS) are rare genetic disorders, caused by enzymatic defects that lead to abnormal glycosaminoglycan metabolism and its accumulation. Hurler-Scheie syndrome (MPS I) is associated with a deficiency of the lysosomal enzyme α-L-iduronidase. Enzymatic replacement with intravenous laronidase is a frequently utilized therapeutic option. In patients with MPS I, progressive glycosaminoglycan storage in the heart can lead to valvular abnormalities; however, few surgical heart valve interventions have been reported in MPS I patients. We present an unusual case of a double-valve replacement in an MPS I patient, complicated by early infective endocarditis requiring surgical reintervention. We also present a comprehensive literature review of valve surgery in patients with MPS I and a brief summary of the most relevant surgical considerations, including valve selection and infection prevention.

In vitro evaluation of (S)-ibuprofen toxicity on joint cells and explants of cartilage and synovial membrane

Intra-articular drug delivery systems (DDSs) are envisaged as interesting alternative to locally release nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen to reduce pain in patients with osteoarthritis. The present study examines the toxicity of (S)-ibuprofen on chondrocytes and synoviocytes isolated from sheep shoulder joint and cultured in monolayers during 72h, and on joint explants (cartilage and capsule) cultured in mono- or in co-culture for 13days. (S)-ibuprofen (5μM up to 1mM) did not reduce the cell viability and protein content when added on chondrocyte monolayers, while at 1mM (S)-ibuprofen reduced (by 8%, p=0.01) the synoviocytes viability compared to untreated cells. During co-culture of joint explants, (S)-ibuprofen at 50μM significantly reduced by 35% the spontaneous release of glycosaminoglycans (GAGs) from cartilage (p=0.0065) whereas in monoculture, (S)-ibuprofen was inactive on GAG metabolism. (S)-ibuprofen at 1mM significantly reduced cell lysis (lactate dehydrogenase leakage) by 74% during monoculture of capsule explants (p=0.0136) and by 35% during co-culture of explants (p=0.0013). Our findings demonstrate that the active isomer of ibuprofen at micro- and millimolar levels was not toxic for chondrocytes and synoviocytes and may reduce at 1mM the cell lysis during culture of joint explants. The limited toxicity of (S)-ibuprofen at low and high concentration in sheep joint shoulder makes this enantiomer a promising drug candidate for the loading of intra-articular DDS.