Protein Replacement Therapy Partially Corrects the Cholesterol-Storage Phenotype in a Mouse Model of Niemann-Pict Type C2 Disease

Niemann-Pick type C2 (NPC2) disease is a fatal autosomal recessive neurovisceral degenerative disorder characterized by late endosomal-lysosomal sequestration of low-density lipoprotein derived cholesterol. The breach in intracellular cholesterol homeostasis is caused by deficiency of functional NPC2, a soluble sterol binding protein targeted to the lysosomes by binding the mannose-6-phosphate receptor. As currently there is no effective treatment for the disorder, we have investigated the efficacy of NPC2 replacement therapy in a murine gene-trap model of NPC2-disease generated on the 129P2/OlaHsd genetic background. NPC2 was purified from bovine milk and its functional competence assured in NPC2-deficient fibroblasts using the specific cholesterol fluorescent probe filipin. For evaluation of phenotype correction in vivo, three-week-old NPC2−/− mice received two weekly intravenous injections of 5 mg/kg NPC2 until trial termination 66 days later. Whereas the saline treated NPC2−/− mice exhibited massive visceral cholesterol storage as compared to their wild-type littermates, administration of NPC2 caused a marked reduction in cholesterol build up. The histological findings, indicating an amelioration of the disease pathology in liver, spleen, and lungs, corroborated the biochemical results. Little or no difference in the overall cholesterol levels was observed in the kidneys, blood, cerebral cortex and hippocampus when comparing NPC2−/− and wild type mice. However, cerebellum cholesterol was increased about two fold in NPC2−/− mice compared with wild-type littermates. Weight gain performance was slightly improved as a result of the NPC2 treatment but significant motor coordination deficits were still observed. Accordingly, ultrastructural cerebellar abnormalities were detected in both saline treated and NPC2 treated NPC2−/− animals 87 days post partum. Our data indicate that protein replacement may be a beneficial therapeutic approach in the treatment of the visceral manifestations in NPC2 disease and further suggest that neurodegeneration is not secondary to visceral dysfunction

Protein Replacement Therapy Partially Corrects the Cholesterol-Storage Phenotype in a Mouse Model of Niemann-Pick Type C2 Disease

Niemann-Pick type C2 (NPC2) disease is a fatal autosomal recessive neurovisceral degenerative disorder characterized by late endosomal-lysosomal sequestration of low-density lipoprotein derived cholesterol. The breach in intracellular cholesterol homeostasis is caused by deficiency of functional NPC2, a soluble sterol binding protein targeted to the lysosomes by binding the mannose-6-phosphate receptor. As currently there is no effective treatment for the disorder, we have investigated the efficacy of NPC2 replacement therapy in a murine gene-trap model of NPC2-disease generated on the 129P2/OlaHsd genetic background. NPC2 was purified from bovine milk and its functional competence assured in NPC2-deficient fibroblasts using the specific cholesterol fluorescent probe filipin. For evaluation of phenotype correction in vivo, three-week-old NPC2−/− mice received two weekly intravenous injections of 5 mg/kg NPC2 until trial termination 66 days later. Whereas the saline treated NPC2−/− mice exhibited massive visceral cholesterol storage as compared to their wild-type littermates, administration of NPC2 caused a marked reduction in cholesterol build up. The histological findings, indicating an amelioration of the disease pathology in liver, spleen, and lungs, corroborated the biochemical results. Little or no difference in the overall cholesterol levels was observed in the kidneys, blood, cerebral cortex and hippocampus when comparing NPC2−/− and wild type mice. However, cerebellum cholesterol was increased about two fold in NPC2−/− mice compared with wild-type littermates. Weight gain performance was slightly improved as a result of the NPC2 treatment but significant motor coordination deficits were still observed. Accordingly, ultrastructural cerebellar abnormalities were detected in both saline treated and NPC2 treated NPC2−/− animals 87 days post partum. Our data indicate that protein replacement may be a beneficial therapeutic approach in the treatment of the visceral manifestations in NPC2 disease and further suggest that neurodegeneration is not secondary to visceral dysfunction

Impaired aortic distensibility and elevated central blood pressure in Turner Syndrome:a cardiovascular magnetic resonance study

Abstract Background Women with Turner Syndrome have an increased risk for aortic dissection. Arterial stiffening is a risk factor for aortic dilatation and dissection. Here we investigate if arterial stiffening can be observed in Turner Syndrome patients and is an initial step in the development of aortic dilatation and subsequent dissection. Methods Fifty-seven women with Turner Syndrome (48 years [29–66]) and thirty-six age- and sex-matched controls (49 years [26–68]) were included. Distensibility, blood pressure, carotid-femoral pulse wave velocity (PWV), the augmentation index (Aix) and central blood pressure were determined using cardiovascular magnetic resonance, a 24-h blood pressure measurement and applanation tonometry. Aortic distensibility was determined at three locations: ascending aorta, transverse aortic arch, and descending aorta. Results Mean aortic distensibility in the descending aorta was significantly lower in Turner Syndrome compared to healthy controls (P = 0.02), however, this was due to a much lower distensibility among Turner Syndrome with coarctation, while Turner Syndrome without coarctation had similar distensibility as controls. Both the mean heart rate adjusted Aix (31.4% vs. 24.4%; P = 0.02) and central diastolic blood pressure (78.8 mmHg vs. 73.7 mmHg; P = 0.02) were higher in Turner Syndrome compared to controls, and these indices correlated significantly with ambulatory night-time diastolic blood pressure. The presence of aortic coarctation (r = − 0.44, P = 0.005) and a higher central systolic blood pressure (r = − 0.34, P = 0.03), age and presence of diabetes were inversely correlated with aortic distensibility in TS. Conclusion Aortic wall function in the descending aorta is impaired in Turner Syndrome with lower distensibility among those with coarctation of the aorta, and among all Turner Syndrome higher Aix, and elevated central diastolic blood pressure when compared to sex- and age-matched controls. Trial registration The study was registered at ClinicalTrials.gov (#NCT01678274) on September 3, 2012

Inter -and intraobserver variation of ultrasonographic cartilage thickness assessments in small and large joints in healthy children

<p>Abstract</p> <p>Background</p> <p>There is an increasing interest among pediatric rheumatologist for using ultrasonography (US) in the daily clinical examination of children with juvenile idiopathic arthritis (JIA). Loss of joint cartilage may be an early feature of destructive disease in JIA. However, US still needs validation before it can be used as a diagnostic bedside tool in a pediatric setting. This study aims to assess the inter- and intraobserver reliability of US measurements of cartilage thickness in the joints of healthy children.</p> <p>Methods</p> <p>740 joints of 74 healthy Caucasian children (27 girls/47 boys), aged 11.3 (7.11 – 16) years were examined with bilateral US in 5 preselected joints to assess the interobserver variability. In 17 of these children (6 girls/11 boys), aged 10.1(7.11–11.1) years, 170 joints was examined in an intraobserver sub study, with a 2 week interval between the first and second examination.</p> <p>Results</p> <p>In this study we found a good inter- and intraobserver agreement expressed as a coefficient of variation (CV) less than 10% in the knee (CV = 9.5%_{interobserver}and 5.9%_{intraobservserI}, 9.3%_{intraobserverII}respectively for the two intraobserver measurements) and fairly good for the MCP joints (CV = 11.9%_{interobserver}, 12.9%_{intraobserverI}and 11.9%_{intraobsevrerII}). In the ankle and PIP joints the inter- and intraobserver agreement was within an acceptable limit (CV<20%) but not for the wrist joint (CV>26%). We found no difference in cartilage thickness between the left and right extremity in the investigated joints.</p> <p>Conclusion</p> <p>We found a good inter -and intraobserver agreement when measuring cartilage thickness with US. The inter- and intraobserver variation seemed not to be related to joint size. These findings suggest that positioning of the joint and the transducer is of major importance for reproducible US measurements. We found no difference in joint cartilage thickness between the left and right extremity in any of the examined joint of the healthy children. This is an important finding giving the opportunity of using the non-affected extremity as a reference when assessing articular joint cartilage damage in JIA.</p