Establishment of the effectiveness of early versus late stem cell gene therapy in Mucopolysaccharidosis II for treating central versus peripheral disease

Mucopolysaccharidosis type II (MPSII) is a rare paediatric X-linked lysosomal storage disease, caused by heterogeneous mutations in the IDS gene, which result in accumulation of heparan sulphate and dermatan sulphate within cells. This leads to severe skeletal abnormalities, hepatosplenomegaly and cognitive deterioration. The progressive nature of the disease is a huge obstacle to achieve full neurological correction. Although current therapies can only treat somatic symptoms, a lentivirus-based hematopoietic stem cell gene therapy (HSCGT) approach has recently achieved improved central nervous system neuropathology in the MPSII mouse model following transplant at 2-months of age. Here we evaluate neuropathology progression in 2-month, 4-month and 9-month-old MPSII mice and using the same HSCGT strategy we investigated somatic and neurological disease attenuation following treatment at 4-months of age. Our results showed gradual accumulation of heparan sulphate between 2 and 4 months of age, but full manifestation of microgliosis/astrogliosis as early as 2 months. Late HSCGT fully reversed the somatic symptoms, thus achieving the same degree of peripheral correction as early therapy. However, late treatment resulted in slightly decreased efficacy in the CNS, with poorer brain enzymatic activity, together with reduced normalisation of heparan sulphate over-sulphation. Overall, our findings confirm significant lysosomal burden and neuropathology in 2-month-old MPSII mice. Peripheral disease is readily reversible by LV.IDS-HSCGT regardless of age of transplant, suggesting a viable treatment for somatic disease. However, in the brain, higher IDS enzyme levels are achievable with early HSCGT treatment, and later transplant seems to be less effective, supporting the view that the earlier patients are diagnosed and treated, the better the therapy outcome

Variation of the omega-3 content of Australian food products

Abstract from the 2008 Annual Scientific Meeting of the Nutrition Society of Australia, 30 November - 3 December 2008, Glenelg, Australia

Fusion of RVG or gh625 to Iduronate-2-Sulfatase for the Treatment of Mucopolysaccharidosis Type II

Mucopolysaccharidosis type II (MPSII) is a lysosomal storage disease caused by a mutation in the IDS gene, resulting in deficiency of the enzyme iduronate-2-sulfatase (IDS) causing heparan sulfate (HS) and dermatan sulfate (DS) accumulation in all cells. This leads to skeletal and cardiorespiratory disease with severe neurodegeneration in two thirds of sufferers. Enzyme replacement therapy is ineffective at treating neurological disease, as intravenously-delivered IDS is unable to cross the blood-brain barrier (BBB). Haematopoietic stem cell transplant is also unsuccessful, presumably due to insufficient IDS enzyme production from transplanted cells engrafting in the brain. We used two different peptide sequences (RVG and gh625), both previously published as BBB-crossing peptides, fused to IDS and delivered via haematopoietic stem cell gene therapy (HSCGT). HSCGT with LV.IDS.RVG and LV.IDS.gh625 was compared to LV.IDS.ApoEII and LV.IDS in MPSII mice at 6-months post-transplant. Levels of IDS enzyme activity in the brain and peripheral tissues were lower in LV.IDS.RVG and LV.IDS.gh625 treated mice than in LV.IDS.ApoEII and LV.IDS treated mice, despite comparable vector copy numbers. Microgliosis, astrocytosis and lysosomal swelling were partially normalised in MPSII mice treated with LV.IDS.RVG and LV.IDS.gh625. Skeletal thickening was normalised by both treatments to wild-type levels. Although reductions in skeletal abnormalities and neuropathology are encouraging, given the low levels of enzyme activity compared to control tissue from LV.IDS and LV.IDS.ApoEII transplanted mice, the RVG and gh625 peptides are unlikely to be ideal candidates for HSCGT in MPSII, and are inferior to the ApoEII peptide that we have previously demonstrated to be more effective at correcting MPSII disease than IDS alone

Developing dietary advice guides for food-based clinical trials

Randomised controlled trials provide the highest level of evidence for the effects of foods and food components on health. Study designs require detailed dietary modelling to control for food and nutrient variables which should parallel with easy to follow dietary education materials to assist in meeting nutrient targets. The aim of this project was to develop dietary advice guides for a clinical trial examining the effects of omega-3 fatty acids on weight loss over a 12 month period. Initially, food-based models for the dietary targets were developed for different energy levels. The research team then identified issues relating to categories of food information to be provided to participants. Visual representations of the information were trialled within the team. Dietary models and advice were based on six food categories. The advice models focussed on the number of servings per day. The protein category needed individual sub-categories to be formed and number of serves prescribed per week. The issues identified included the determination of serving size, sub-categories of foods within each group, qualifying information and using motivational messages to encourage consumption from each category. Consistency in the visual representations were considered of value to ensure pattern recognition of information on each new category of food. The development of dietary advice guides for use in clinical trials requires effective control of dietary variables presented and poses a number of design challenges which may be overcome by drawing on a range of dietetic skills from within the research team. Funding Source: NHMRC Project Grant #514631 Contact Details: Rebecca Thorne, (02) 4221 5992, [email protected]

Relative validity of three different dietary assessment tools as a part of a food-based clinical trial for weight loss

Clinical trials require standardised dietary practices to allow prescribed dietary targets to be achieved and monitored. The methods of dietary intake assessment play a vital role in this process, though new innovative methods may help to streamline the process further. This cross-sectional study aims to statistically compare the nutrient data obtained at baseline from diet history (DH), food record (FR) and self-administered computerised dietary assessments (DA) conducted in a food-based clinical trial for weight-loss. Data for n=71 (n=15 male and n=56 female participants, 45.4±7.9yrs, BMI 31.6±3.5kg/m²) was obtained of which 69 matching DH and FR, 32 matching DH and DA and 30 matching FR and DA were available. Significant differences were found for all macronutrients for all matching assessment methods. The relationship between assessment methods varied widely: DH-DA (r=0.123-0.704), DH-FR (r=0.241-0.504), DA-FR (r=0.250-0.596). For energy (kJ) DA had the strongest correlations (DH r=0.704, FR r=0.596) compared with DH and FR (r=0.425). The nutrient with the weakest correlations for all assessment methods were the monounsaturated fatty acids (DH-FR r=0.320, DH-DA r=0.123, DA-FR r=0.250). Interestingly, Bland-Altman analyses for DA-FR and DA-DH showed identical scatter patterns for energy (kJ). The results suggest that the food record and computerised dietary assessments are most comparable at baseline possibly due to the method of administration (participant completed). Though the sample size is small, these results suggest that new computer-based technologies for dietetics may provide added benefits in the clinical trials setting. Funding source: The work of this project was funded under an NHMRC project grant and a University of Wollongong Early Career Researcher Health and Behavioural Sciences grant

Start date may predict attrition 6 months into a 12mth dietary intervention weight loss trial

Participant recruitment is a difficult and time consuming aspect of clinical trials, often resulting in delays and budget overruns. Having reached recruitment targets the next challenge is participant retention. Some weight-loss studies have attrition rates around 60% which may introduce bias in the results. It may be possible to reduce attrition rates if known predictors can be found but to date few studies produced consistent results. The aim of this exploratory study was to determine whether start date could be a predictor of attrition for participants involved in the SMART weight loss clinical trial (ACTRN12608000425392). Recruitment for the trial occurred as two cohorts at different times of the year. The relationship between attrition and cohort was determined using a Pearson chi square analysis. At three months 31% of Cohort 1 had withdrawn compared with 18% of Cohort 2. Cohort 1 participants, (enrolled July to November) were significantly more likely to withdraw within 6 months than Cohort 1 (January to March) (P=0.049). In each cohort most withdrawals occurred within the first three months. For Cohort 1, this coincided with the period leading up to Christmas and summer holidays. Changes in routines and increased food temptations at this time of year are known challenges of weight management and this may explain the significant difference between cohort withdrawal rates. The period around Easter and autumn holidays did not seem to have the same effect. Adjusting start dates and developing strategies to minimise the effect of seasonal holidays may help reduce attrition rates.

Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo

International audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]† Deceased, August 2020