Endothelial function in children and adolescents with mucopolysaccharidosis.
ABSTRACT BACKGROUND: Although coronary artery pathology is a prominent feature of mucopolysaccharidosis (MPS), it may be underestimated by coronary angiography because of its diffuse nature. It is also generally assumed that cardiovascular risk is increased in MPS and reduced following hematopoietic stem cell transplantation (HSCT) or enzyme replacement therapy (ERT), but this has never been formally evaluated. Non-invasive methods of assessing vascular endothelial function may provide a measure of cardiovascular risk in MPS. We evaluated endothelial function, using digital reactive hyperemia, in youth with MPS and in healthy controls. METHODS: Digital reactive hyperemic index (RHI) was measured in 12 children and adolescents (age 10.3 ± 3.9 years old; 11 boys) with treated MPS and nine age- and gender-matched (11.4 ± 4.0; 8 boys) healthy controls. An independent t-test was used to compare RHI between individuals with MPS and controls. RESULTS: Children and adolescents with MPS (MPS type II: N = 5; type I: N = 4; type VI: N = 3) whether treated by HSCT (N = 4) or ERT (N = 8) had significantly lower RHI compared to controls (MPS 1.22 ± 0.19 vs. controls 1.46 ± 0.32, p < 0.05). CONCLUSION: These preliminary findings suggest that children and adolescents with treated MPS have significantly poorer endothelial function when compared to healthy controls. Further investigation into the utility of endothelial function for risk stratification and the long term implications of reduced endothelial function in MPS is warranted.
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ABSTRACT: We investigated the value of reactive hyperemia peripheral arterial tonometry (RH-PAT) as a noninvasive tool to identify individuals with coronary microvascular endothelial dysfunction. Coronary endothelial dysfunction, a systemic disorder, represents an early stage of atherosclerosis; RH-PAT is a technique to assess peripheral microvascular endothelial function. Using RH-PAT, digital pulse volume changes during reactive hyperemia were assessed in 94 patients without obstructive coronary artery disease and either normal (n = 39) or abnormal (n = 55) coronary microvascular endothelial function; RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at baseline. Average RH-PAT index was lower in patients with coronary endothelial dysfunction compared with those with normal coronary endothelial function (1.27 +/- 0.05 vs. 1.78 +/- 0.08: p < 0.001). An RH-PAT index <1.35 was found to have a sensitivity of 80% and a specificity of 85% to identify patients with coronary endothelial dysfunction. Digital hyperemic response, as measured by RH-PAT, is attenuated in patients with coronary microvascular endothelial dysfunction, suggesting a role for RH-PAT as a noninvasive test to identify patients with this disorder.Journal of the American College of Cardiology 01/2005; 44(11):2137-41. · 14.09 Impact Factor
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ABSTRACT: Mucopolysaccharidosis type I (MPS I) is a rare lysosomal storage disease subdivided into three phenotypes of increasing severity: Scheie, Hurler-Scheie and Hurler. To gauge the effectiveness of treatments and to determine the load likely to fall on health-care systems, it is necessary to understand the prevalence and natural progression of the disease especially with regard to life-expectancy. In general such data on the natural history of lysosomal storage diseases is sparse. Analysis of prevalence and patient survival in MPS I disease using a unique longitudinal data set initiated and maintained over a period of more than 20 years by the Society for Mucopolysaccharide Diseases (UK). The birth prevalence of MPS I in England and Wales over the period 1981 to 2003 was 1.07/100,000 births and within +/- 5% of estimates reported in several studies that examined reasonably large populations. The median survival for MPS I patients (including all phenotypes irrespective of various treatments) was found by Kaplan-Meier analysis to be 11.6 years. This result was driven by the relatively poor survival of patients with the Hurler phenotype who, irrespective of any treatments received, had a median survival of 8.7 years; when censoring for receipt of bone marrow transplant (BMT) was implemented median survival of Hurler patients was diminished to 6.8 years. The difference between these survival curves was statistically significant by log rank test and can be attributed to beneficial effects of BMT and or selection of patients with superior prognosis for intervention with BMT. Survival curves for Hurler patients who received and did not receive BMT were very different. Probability of survival at 2 year after BMT was ~68% and was similar to this after 5 years (66%) and ten years (64%); the mean age of Hurler patients at receipt of BMT was 1.33 years (range 0.1 to 3 years). Follow up was insufficient to determine median survival of the milder phenotypes however, unsurprisingly, this was clearly superior to that for Hurler patients. The birth prevalence of MPS I in England and Wales is 1.07/100,000 and the median survival for MPS I patients is 11.6 years.Orphanet Journal of Rare Diseases 10/2008; 3:24. · 4.32 Impact Factor
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ABSTRACT: Mucopolysaccharidosis type I (MPS IS) is a rare autosomal recessive disease caused by a deficiency of the lysosomal enzyme alpha-L-iduronidase, which is involved in the degradation of sulfated glycosaminoglycans (GAGs). The deficiency results in the intra-and pericellular accumulation of the GAGs heparan sulfate and dermatan sulfate. Eight adult patients with typical features of MPS IS aged 31.5 +/- 6.8 years (five men) were included and compared to age-and gender-matched controls. With transthoracic echocardiography, cyclic ascending aortic diameter changes were measured and ascending aortic elastic properties were calculated to characterize aortic elasticity. In MPS IS patients, aortic stiffness index was significantly increased (23.1 +/- 10.4 vs 3.9 +/- 1.5, P < 0.001), while aortic distensibility was significantly decreased (1.6 +/- 0.8 vs 4.6 [corrected] +/- 1.9 cm(2)/dynes [corrected] 10(-6), P < 0.001) compared to age-and sex-matched controls. The results of the present study demonstrate that in addition to the known cardiac complications, MPS IS patients have an impairment of ascending aortic elasticity. Further follow-up studies are needed to examine arterial elasticity using other methods in this patient population, and to detect possible effects of enzyme replacement therapy.Heart and Vessels 03/2008; 23(2):108-11. · 2.13 Impact Factor