Prognostic factors for changes in the timed 4-stair climb in patients with Duchenne muscular dystrophy, and implications for measuring drug efficacy: A multi-institutional collaboration

The timed 4-stair climb (4SC) assessment has been used to measure function in Duchenne muscular dystrophy (DMD) practice and research. We sought to identify prognostic factors for changes in 4SC, assess their consistency across data sources, and the extent to which prognostic scores could be useful in DMD clinical trial design and analysis. Data from patients with DMD in the placebo arm of a phase 3 trial (Tadalafil DMD trial) and two real-world sources (Universitaire Ziekenhuizen, Leuven, Belgium [Leuven] and Cincinnati Children\u27s Hospital Medical Center [CCHMC]) were analyzed. One-year changes in 4SC completion time and velocity (stairs/second) were analyzed. Prognostic models included age, height, weight, steroid use, and multiple timed function tests and were developed using multivariable regression, separately in each data source. Simulations were used to quantify impacts on trial sample size requirements. Data on 1-year changes in 4SC were available from the Tadalafil DMD trial (n = 92) Leuven (n = 67), and CCHMC (n = 212). Models incorporating multiple timed function tests, height, and weight significantly improved prognostic accuracy for 1-year change in 4SC (R2: 29%-36% for 4SC velocity, and 29%-34% for 4SC time) compared to models including only age, baseline 4SC and steroid duration (R2:8%-17% for 4SC velocity and 2%-13% for 4SC time). Measures of walking and rising ability contributed important prognostic information for changes in 4SC. In a randomized trial with equal allocation to treatment and placebo, adjustment for such a prognostic score would enable detection (at 80% power) of a treatment effect of 0.25 stairs/second with 100-120 patients, compared to 170-190 patients without prognostic score adjustment. Combining measures of ambulatory function doubled prognostic accuracy for 1-year changes in 4SC completion time and velocity. Randomized clinical trials incorporating a validated prognostic score could reduce sample size requirements by approximately 40%. Knowledge of important prognostic factors can also inform adjusted comparisons to external controls

Percutaneous Mitral Valve Repair versus Optimal Medical Therapy in Patients with Functional Mitral Regurgitation: A Systematic Review and Meta-Analysis

Objectives. To compare percutaneous mitral valve repair (PMVR) with optimal medical therapy (OMT) in patients with heart failure (HF) and severe functional mitral regurgitation (FMR). Background. Many patients with HF and FMR are not suitable for surgical valve replacement and remain symptomatic despite maximal OMT. PMVR has recently emerged as an alternative solution. Methods. We performed a systematic review and a meta-analysis to address this question. Cochrane CENTRAL, MEDLINE, and Scopus were searched for randomized (RCT) and nonrandomized studies comparing PMVR with OMT in patients with HF and FMR. Primary endpoint was all-cause midterm mortality (at 1 and 2 years). Secondary endpoints were 30-day mortality and cardiovascular mortality and HF hospitalizations, at maximum follow-up. Studies including mixed cohort of degenerative and functional MR were allowed initially but were excluded in a secondary sensitivity analysis for each of the study’s end points. This meta-analysis was performed following the publication of two RCTs (MITRA-FR and COAPT). Results. Eight studies (six observational, two RCTs) comprising 3,009 patients were included in the meta-analysis. In comparison with OMT, PMVR significantly reduced 1-year mortality (RR: 0.70 [0.56, 0.87]; p=0.002; I2=47.6%), 2-year mortality (RR: 0.63 [0.55, 0.73]; p\u3c0.001; I2=0%), and cardiovascular mortality (RR: 0.32 [0.23, 0.44]; p\u3c0.001; I2=0%). No significant difference between PMVR+OMT and OMT was noted in HF hospitalization (HR: 0.69 [0.40, 1.20]; p=0.19; I2=85%) and 30-day mortality (RR: 1.13 [0.68, 1.87]; p=0.16; I2=0%). Conclusions. In comparison with OMT, PMVR significantly reduces 1-year mortality, 2-year mortality, and cardiovascular mortality in patients with HF and severe MR

Chondroprotection by urocortin involves blockade of the mechanosensitive ion channel Piezo1

Osteoarthritis (OA) is characterised by progressive destruction of articular cartilage and chondrocyte cell death. Here, we show the expression of the endogenous peptide urocortin1 (Ucn1) and two receptor subtypes, CRF-R1 and CRF-R2, in primary human articular chondrocytes (AC) and demonstrate its role as an autocrine/paracrine pro-survival factor. This effect could only be removed using the CRF-R1 selective antagonist CP-154526, suggesting Ucn1 acts through CRF-R1 when promoting chondrocyte survival. This cell death was characterised by an increase in p53 expression, and cleavage of caspase 9 and 3. Antagonism of CRF-R1 with CP-154526 caused an accumulation of intracellular calcium (Ca2+) over time and cell death. These effects could be prevented with the non-selective cation channel blocker Gadolinium (Gd3+). Therefore, opening of a non-selective cation channel causes cell death and Ucn1 maintains this channel in a closed conformation. This channel was identified to be the mechanosensitive channel Piezo1. We go on to determine that this channel inhibition by Ucn1 is mediated initially by an increase in cyclic adenosine monophosphate (cAMP) and a subsequent inactivation of phospholipase A2 (PLA2), whose metabolites are known to modulate ion channels. Knowledge of these novel pathways may present opportunities for interventions that could abrogate the progression of OA

Insight Into the Interaction Between RNA Polymerase and VPg for Murine Norovirus Replication

Norovirus (NoV) is a leading cause of epidemic acute non-bacterial gastroenteritis, and replicates through virion protein genome-linked (VPg)-primed or de novo RNA synthesis by RNA-dependent RNA polymerase (RdRp). VPg is a multifunctional protein that plays crucial roles in viral protein translation and genome replication. However, the interaction between the RdRp and this multifunctional VPg in NoV replication has been unknown. In this study, VPg derived from murine NoV (MNV) was found to mediate the formation of higher-order multimers or tubular fibrils of MNV RdRp, which led to significantly enhanced polymerase activity in vitro. The replication of MNV mutants containing a VPg-binding defective RdRp, based on the crystal structure of an RdRp-VPg(1-73) complex, was completely blocked in a cell culture system. Our data suggest that the interaction between RdRp and VPg plays a crucial role in the multimerization-mediated RdRp activity in vivo and consequently in MNV replication, which can provide a new target of therapeutic intervention for NoV outbreaks

Osteoarthritis: 119. The Effectiveness of Exercise Therapy with and without Manual Therapy for Hip Osteoarthritis: A Multicentre Randomised Controlled Trial

Background: Current evidence indicates that exercise therapy (ET) has a short and medium-term benefit for hip osteoarthritis (OA), but evidence is inconclusive regarding the effect of manual therapy (MT). The primary aim of this randomised controlled trial was to determine the effectiveness of ET with and without MT on clinical outcomes for individuals with hip OA. A secondary aim was to ascertain the effect of an 8-week waiting period on outcomes. Methods: 131 men and women with hip OA recruited in four hospitals were initially randomised to one of three groups: ET (n = 45), a combination of ET and MT (n = 43) and wait-list control (n = 43). The two intervention groups underwent individualised ET or ET/MT for 8 weeks. Patients in the control group waited 8 weeks and were randomised to receive either ET or ET/MT after 9 week follow-up, and pooled with original treatment group data: ET (n = 66) and ET/ MT (n = 65). All participants were followed up at 9 and 18 weeks and the control group was reassessed at 27 weeks (18 weeks post-treatment) by the same blinded assessor. The primary outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Other outcomes included sit-to-stand, 50-foot walk test, pain severity, hip range of motion (ROM), anxiety, depression, quality of life (QOL), analgesic usage, physical activity, patient-perceived change and patient satisfaction. Intention-to-treat analysis was performed to determine within-group change and between-group differences for the three groups at baseline and 9 weeks, and the two treatment groups at baseline, 9 and 18 weeks. Results: Eight patients (6.1%) were lost to follow-up at 9 weeks and 19 (14.5%) were lost to follow-up by 18 weeks. Both ET (n = 66) and ET/MT groups (n = 65) showed significant within-group improvements in WOMAC, pain severity, sit-to-stand and HROM measures at 9 weeks, which were still evident at 18 weeks. There was no significant within-group change in anxiety, depression, QOL, analgesic usage, 50-foot walk test or physical activity. There was no significant difference between the two intervention groups for any of the outcomes. Regarding the results of the original ET, ET/MT and control group allocation, there was a significant improvement in one or both ET and ET/MT groups compared with the control group in the same outcomes, as well as patient perceived improvement at 9 weeks. There was no significant difference between the three groups in analgesic usage, WOMAC stiffness subscale, sit-to-stand and 50 foot walk tests, QOL and physical activity. There was an overall deterioration in anxiety and depression scores. Conclusions: The addition of MT to an 8 week programme of ET for hip OA resulted in similar improvements in pain, function and ROM at 9 and 18 weeks. The significant improvement which occurred in the same outcomes in the two treatment groups compared with a wait-list control of 8 weeks has implications for waiting list management Disclosure statement: The authors have declared no conflicts of interes

Melanocortin peptides protect chondrocytes from mechanically induced cartilage injury

Introduction Mechanical injury can greatly influence articular cartilage, propagating inflammation, cell injury and death – risk factors for the development of osteoarthritis. Melanocortin peptides and their receptors mediate anti-inflammatory and pro-resolving mechanisms in chondrocytes. This study aimed to investigate the potential chondroprotective properties of α-MSH and [DTRP8]-γ-MSH in mechanically injured cartilage explants, their ability to inhibit pro-inflammatory and stimulate anti-inflammatory cytokines in in situ and in freshly isolated articular chondrocytes. Methods The effect of melanocortins on in situ chondrocyte viability was investigated using confocal laser scanning microscopy of bovine articular cartilage explants, subjected to a single blunt impact (1.14 N, 6.47 kPa) delivered by a drop tower. Chondroprotective effects of α-MSH, [DTRP8]-γ-MSH and dexamethasone on cytokine release by TNF-α-activated freshly isolated articular chondrocytes/mechanically injured cartilage explants were investigated by ELISA. Results A single impact to cartilage caused discreet areas of chondrocyte death, accompanied by pro-inflammatory cytokine release; both parameters were modulated by α-MSH, [DTRP8]-γ-MSH and dexamethasone. Melanocortin pre-treatment of TNF-α-stimulated freshly isolated chondrocytes resulted in a bell-shaped inhibition in IL-1β, IL-6 and IL-8, and elevation of IL-10 production. The MC3/4 antagonist, SHU9119, abrogated the effect of [DTRP8]-γ-MSH but not α-MSH on cytokine release. Conclusion Melanocortin peptide pre-treatment prevented chondrocyte death following mechanical impact to cartilage and led to a marked reduction of pro-inflammatory cytokines, whilst prompting the production of anti-inflammatory/pro-resolving cytokine IL-10. Development of small molecule agonists towards melanocortin receptors could thus be a viable approach for preventing chondrocyte inflammation and death within cartilage and represent an alternative approach for the treatment of osteoarthritis

Short periods of cyclic mechanical strain enhance triple-supplement directed osteogenesis and bone nodule formation by human embryonic stem cells in vitro

10.1089/ten.tea.2012.0308Tissue Engineering - Part A1919-202130-213