Modulation of estrogen signaling in hepatic and vascular tissue

This thesis centers on the mechanisms of estrogen action and the effects on the development of atherosclerosis. We have focused on the liver as central organ in lipid and glucose metabolism and the vessel wall as the actual site where the injury occurs. To gain insight in tissue-specific actions of estrogens, we have spent considerable effort to develop tools for liver and blood vessel specific modulation of the estrogen receptor (ER) signaling cascade. The generation, characterization and application of these tools in vitro and in vivo will be described in the different chapters of this thesis.LEI Universiteit LeidenDr. ir. Van de Laar Stichting J.E. Juriaanse StichtingDe pathogenese, kliniek en behandeling van arterieel en veneus vaatlijde

Compliance to DMD care considerations in the Netherlands

Background and objective: To optimize care for patients with DMD, it is essential to know to what extent current care complies with the recommended monitoring frequencies suggested by the DMD care considerations. The objective of this study was to investigate the current care for patients with DMD in the Netherlands and to what extent the care complies with the international care considerations.Methods: A cross-sectional questionnaire was carried out among the Dutch DMD patients and caregivers about the patients' functional and health status, visits to healthcare professionals, clinical tests and assessments, therapy, medication use and access to medical aids and devices. Compliance to guidelines was defined by comparing the frequency of visits to health care providers and clinical tests with the recommended frequencies derived from the care considerations of 2010.Results: Eighty-four participants completed the questionnaire. The majority of participants met the recommended visit frequencies to a neuromuscular specialist and cardiologist. Compliance was suboptimal for respiratory assessments in the non-ambulatory phase, monitoring of side effects of corticosteroid use and neuromuscular assessments. Disease specific information supply was perceived as sufficient and participants were satisfied with the received care.Conclusions: This study identifies areas in which compliance is lacking. Countries, such as the Netherlands, working according to a shared care system require easy and low-threshold communication between health care centers and a clear division of roles and responsibilities to reach optimal compliance. In the Netherlands the Duchenne Center Netherlands has the coordinating role.Neurological Motor Disorder

Dnmt3bregulates DUX4 expression in a tissue-dependent manner in transgenic D4Z4 mice

Background Facioscapulohumeral muscular dystrophy (FSHD) is a skeletal muscle disorder that is caused by derepression of the transcription factor DUX4 in skeletal muscle cells. Apart from SMCHD1, DNMT3B was recently identified as a disease gene and disease modifier in FSHD. However, the exact role of DNMT3B at the D4Z4 repeat array remains unknown. Methods To determine the role of Dnmt3b on DUX4 repression, hemizygous mice with a FSHD-sized D4Z4 repeat array (D4Z4-2.5 mice) were cross-bred with mice carrying an in-frame exon skipping mutation inDnmt3b(Dnmt3b(MommeD14)mice). Additionally, siRNA knockdowns ofDnmt3bwere performed in mouse embryonic stem cells (mESCs) derived from the D4Z4-2.5 mouse model. Results In mESCs derived from D4Z4-2.5 mice, Dnmt3b was enriched at the D4Z4 repeat array and DUX4 transcript levels were upregulated after a knockdown ofDnmt3b. In D4Z4-2.5/Dnmt3b(MommeD14)mice, Dnmt3b protein levels were reduced; however, DUX4 RNA levels in skeletal muscles were not enhanced and no pathology was observed. Interestingly, D4Z4-2.5/Dnmt3b(MommeD14)mice showed a loss of DNA methylation at the D4Z4 repeat array and significantly higher DUX4 transcript levels in secondary lymphoid organs. As these lymphoid organs seem to be more sensitive to epigenetic modifiers of the D4Z4 repeat array, different immune cell populations were quantified in the spleen and inguinal lymph nodes of D4Z4-2.5 mice crossed with Dnmt3b(MommeD14)mice or Smchd1(MommeD1)mice. Only in D4Z4-2.5/Smchd1(MommeD1)mice the immune cell populations were disturbed. Conclusions Our data demonstrates that loss of Dnmt3b results in derepression of DUX4 in lymphoid tissues and mESCs but not in myogenic cells of D4Z4-2.5/Dnmt3b(MommeD14)mice. In addition, the Smchd1(MommeD1)variant seems to have a more potent role in DUX4 derepression. Our studies suggest that the immune system is particularly but differentially sensitive to D4Z4 chromatin modifiers which may provide a molecular basis for the yet underexplored immune involvement in FSHD.Functional Genomics of Muscle, Nerve and Brain Disorder

Occurrence of symptoms in different stages of Duchenne muscular dystrophy and their impact on social participation

Introduction/Aims: As life expectancy improves for patients with Duchenne muscular dystrophy (DMD), new symptoms are likely to arise. This aims of this study are: (1) to explore the prevalence of a broad variety of symptoms in the various stages of DMD (with and without steroid use); (2) to explore the prevalence of common secondary diagnoses; and (3) to evaluate the social participation level of patients with DMD older than 16 y of age; and to explore correlations between social participation and symptoms.Methods A cross-sectional self-report questionnaire, including questions on functional level and health status, as well as a standardized participation scale was distributed among Dutch patients with DMD.Results Eighty-four male patients with a mean age of 22.0 (SD = 10.0) y were enrolled. The most prevalent and limiting symptoms were difficulty coughing (58%), coldness of hands (57%), contractures (51%), stiffness (49%), fatigue (40%), myalgia (38%), and low speech volume (33%). Prevalent secondary diagnoses included cardiac disease (14%), neurobehavioral diagnosis (13%), low blood pressure (13%), and arthrosis (5%). Social participation correlated negatively with coldness of hands (r = - .29; P < .03), decreased intelligibility (r = - .40; P < .003), and chewing problems (r = - .33; P < .02).Discussion The prevalence of a broad spectrum of symptoms and secondary diagnoses is high in patients with DMD, and some of these symptoms are correlated with social participation. Growing awareness of new symptoms and secondary diagnoses among patients, caregivers, and professionals can enhance their recognition, possibly facilitating prevention and early treatment.Neurological Motor Disorder

Smchd1 haploinsufficiency exacerbates the phenotype of a transgenic FSHD1 mouse model

Functional Genomics of Muscle, Nerve and Brain Disorder

Deep characterization of a common D4Z4 variant identifies biallelic DUX4 expression as a modifier for disease penetrance in FSHD2

Development and application of statistical models for medical scientific researc

Differential myofiber-type transduction preference of adeno-associated virus serotypes 6 and 9

Functional Genomics of Muscle, Nerve and Brain Disorder

Decision-making and selection bias in four observational studies on Duchenne and Becker muscular dystrophy

Background: Natural history data are essential for trial design in Duchenne (DMD) and Becker muscular dystrophy (BMD), but recruitment for observational studies can be challenging.Objective: We reviewed reasons why patients or caregivers declined participation, and compared characteristics of participants and non-participants to assess possible selection bias in four observational studies, three on DMD and one on BMD.Methods: Three pediatric DMD studies focused on cross-sectional cognitive function and brain MRI (DMDbrain, n=35 and DMDperfusion, n = 12), and on longitudinal upper extremity function and muscle MRI (DMDarm, n = 22). One adult BMD study assessed longitudinal functioning (n = 36). Considerations for non-participation were retrospectively reviewed from screening logs. Age, travel-time, DMD gene mutations and age at loss of ambulation (DMDarm and BMD study only), of participants and non-participants were derived from the Dutch Dystrophinopathy Database and compared using nonparametric tests (p Results: The perceived burden of the protocol (38.2%), use of MRI (30.4%), and travel-time to the study site (19.1%) were the most frequently reported considerations for non-participation. Only few patients reported lack of personal gain (0.0–5.9%). Overall, participating patients were representative for the studied sub-populations, except for a younger age of DMDarm study participants and a complete lack of participants with a mutation beyond exon 63.Conclusion: Optimizing patient involvement in protocol design, improving MRI experiences, and integrating research into clinics are important factors to decrease burden and facilitate participation. Nationwide registries are essential to compare participants and non-participants and ensure representative observational research. Specific effort is needed to include patients with distal mutations in cognitive studies.</p

Deep characterization of a common D4Z4 variant identifies biallelic DUX4 expression as a modifier for disease penetrance in FSHD2

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Novel free-circulating and extracellular vesicle-derived miRNAs dysregulated in Duchenne muscular dystrophy

Item does not contain fulltextAim: To perform cross-sectional and longitudinal miRNA profiling in plasma from Duchenne muscular dystrophy (DMD) subjects and find non-invasive biomarkers in DMD. Subjects/materials & methods: Plasma was collected from 14 age and sex matched controls and 46 DMD subjects. Free-circulating and extracellular vesicle (EV)-derived miRNA expression was measured by RT-qPCR. Results: Free-circulating and EVs derived miR-29c-3p and miR-133a-3p are dysregulated in DMD subjects. Free-circulating and EV-derived miR-29c-3p are reduced in DMD subjects undergoing daily corticosteroid treatment. Free-circulating miR-1-3p and miR-122-5p are longitudinally upregulated in ambulant DMD subjects. Conclusion: We detected novel free-circulating and EV-derived dysregulated miRNAs in plasma from DMD subjects and characterized the longitudinal profile of free-circulating miRNA on plasma from DMD subjects