Extracellular matrix disruption is an early event in the pathogenesis of skeletal disease in mucopolysaccharidosis I.

Progressive skeletal and connective tissue disease represents a significant clinical burden in all of the mucopolysaccharidoses. Despite the introduction of enzyme replacement strategies for many of the mucopolysaccharidoses, symptomatology related to bone and joint disease appears to be recalcitrant to current therapies. In order to address these unmet medical needs a clearer understanding of skeletal and connective tissue disease pathogenesis is required. Historically the pathogenesis of the mucopolysaccharidoses has been assumed to directly relate to progressive storage of glycosaminoglycans. It is now apparent for many lysosomal storage disorders that more complex pathogenic mechanisms underlie patients' clinical symptoms. We have used proteomic and genome wide expression studies in the murine mucopolysaccharidosis I model to identify early pathogenic events occurring in micro-dissected growth plate tissue. Studies were conducted using 3 and 5-week-old mice thus representing a time at which no obvious morphological changes of bone or joints have taken place. An unbiased iTRAQ differential proteomic approach was used to identify candidates followed by validation with multiple reaction monitoring mass spectrometry and immunohistochemistry. These studies reveal significant decreases in six key structural and signaling extracellular matrix proteins; biglycan, fibromodulin, PRELP, type I collagen, lactotransferrin, and SERPINF1. Genome-wide expression studies in embryonic day 13.5 limb cartilage and 5 week growth plate cartilage followed by specific gene candidate qPCR studies in the 5week growth plate identified fourteen significantly deregulated mRNAs (Adamts12, Aspn, Chad, Col2a1, Col9a1, Hapln4, Lum, Matn1, Mmp3, Ogn, Omd, P4ha2, Prelp, and Rab32). The involvement of biglycan, PRELP and fibromodulin; all members of the small leucine repeat proteoglycan family is intriguing, as this protein family is implicated in the pathogenesis of late onset osteoarthritis. Taken as a whole, our data indicates that alteration of the extracellular matrix represents a very early event in the pathogenesis of the mucopolysaccharidoses and implies that biomechanical failure of chondro-osseous tissue may underlie progressive bone and joint disease symptoms. These findings have important therapeutic implications.

Reliability of study endpoint adjudication in a pragmatic trial on brain arteriovenous malformations.

BACKGROUND: The results of a clinical trial are given in terms of primary and secondary outcomes that are obtained for each patient. Just as an instrument should provide the same result when the same object is measured repeatedly, the agreement of the adjudication of a clinical outcome between various raters is fundamental to interpret study results. The reliability of the adjudication of study endpoints determined by examination of the electronic case report forms of a pragmatic trial has not previously been tested. METHODS: The electronic case report forms of 62/434 (14%) patients selected to be observed in a study on brain AVMs were independently examined twice (4 weeks apart) by 8 raters who judged whether each patient had reached the following study endpoints: (1) new intracranial hemorrhage related to AVM or to treatment; (2) new non-hemorrhagic neurological event; (3) increase in mRS ≥1; (4) serious adverse events (SAE). Inter and intra-rater reliability were assessed using Gwet's AC1 (κG) statistics, and correlations with mRS score using Cramer's V test. RESULTS: There was almost perfect agreement for intracranial hemorrhage (92% agreement; κG = 0.84 (95%CI: 0.76-0.93), and substantial agreement for SAEs (88% agreement; κG = 0.77 (95%CI: 0.67-0.86) and new non-hemorrhagic neurological event (80% agreement; κG = 0.61 (95%CI: 0.50-0.72). Most endpoints correlated (V = 0.21-0.57) with an increase in mRS of ≥1, an endpoint which was itself moderately reliable (76% agreement; κG = 0.54 (95%CI: 0.43-0.64). CONCLUSION: Study endpoints of a pragmatic trial were shown to be reliable. More studies on the reliability of pragmatic trial endpoints are needed.

Incidence of myeloproliferative neoplasms in Calgary, Alberta, Canada.

OBJECTIVE: The incidence of the combined myeloproliferative neoplasms (MPNs) was determined for a major Canadian city. Retrospective cases of MPN diagnoses (essential thrombocythemia, polycythemia vera, and primary myelofibrosis) between 2011 to 2015 were retrieved from the Southern Alberta Cancer Cytogenetics Laboratory's database at Alberta Public Laboratories. RESULTS: An incidence rate of 2.05 cases per 100,000 person-years (95% CI 1.73-2.41) was determined, giving an age-standardized Canadian incidence of 2.71 cases per 100,000 person years (95% CI 2.63-2.78). MPN diagnoses occurred at a wide age range of 8-93 (median 66) and an age-dependent increase in incidence. Incidence rates for the MPNs are first reported here for a Canadian population.