ALBERT

Description: Facioscapulohumeral muscular dystrophy (FSHD), the most prevalent myopathy afflicting both children and adults, is predominantly associated with contractions in the 4q35-localized macrosatellite D4Z4 repeat array. Recent studies have proposed that FSHD pathology is caused by the misexpression of the DUX4 (double homeobox 4) gene resulting in production of a pathogenic protein, DUX4-FL, which has been detected in FSHD, but not in unaffected control myogenic cells and muscle tissue. Here, we report the analysis of DUX4 mRNA and protein expression in a much larger collection of myogenic cells and muscle biopsies derived from biceps and deltoid muscles of FSHD affected subjects and their unaffected first-degree relatives. We confirmed that stable DUX4-fl mRNA and protein were expressed in myogenic cells and muscle tissues derived from FSHD affected subjects, including several genetically diagnosed adult FSHD subjects yet to show clinical manifestations of the disease in the assayed muscles. In addition, we report DUX4-fl mRNA and protein expression in muscle biopsies and myogenic cells from genetically unaffected relatives of the FSHD subjects, although at a significantly lower frequency. These results establish that DUX4-fl expression per se is not sufficient for FSHD muscle pathology and indicate that quantitative modifiers of DUX4-fl expression and/or function and family genetic background are determinants of FSHD muscle disease progression.

Description: Recent studies suggest increased cancer risk in patients with type 2 diabetes mellitus (T2DM) compared with healthy individuals. The present study aims to assess whether T2DM is associated with increased genome instability and whether a healthy diet with natural foods can improve genome stability in peripheral blood lymphocytes (PBLs). Seventy-six diabetic and 21 non-diabetic individuals were randomly assigned to either an ‘intervention’ or an ‘information only’ group. All participants received information about the beneficial effects of a healthy diet, while subjects of the intervention group received additionally 300g of vegetables and 25ml of plant oil rich in polyunsaturated fatty acids per day for 8 weeks. Chromosomal damage was assessed using the cytokinesis-block micronucleus (MN) cytome assay. Levels of chromosomal damage did not differ between diabetic and non-diabetic individuals. However, diabetic individuals with MN frequency above the high 50th percentile had significantly higher levels of fasting plasma glucose, glycosylated haemoglobin and were at higher risk for cardiovascular disease (CVD), assessed by the Framingham general cardiovascular risk score. Non-diabetic individuals with MN frequency above the 50th percentile had significantly lower vitamin B12 levels. The intervention with vegetables and plant oil led to significant increases in folate, -tocopherol, α- and β-carotene while vitamin B12 was significantly reduced. Levels of chromosomal damage were not altered, only apoptosis was slightly increased. The results suggest interactions between glycaemic control, CVD risk and genome stability in individuals with T2DM. However, a healthy diet does not improve genome damage in PBLs.

Description: Ageing goes hand in hand with altered DNA repair and defence mechanisms against DNA damage. To improve the body’s overall resistance against chromosomal damage, maintaining a healthy and active lifestyle is of great concern, especially in the elderly. As more and more people are getting older, they change from home living to an institutionalised situation, which is often accompanied by malnutrition, depression and inactivity. So far, there is a lack of data on chromosomal damage in relation to age and fitness status. The aim of this study was to examine the effect of age and aerobic fitness on endpoints of DNA damage in 105 institutionalised women and men (65–98 years) living in Vienna. Chromosomal damage was measured by conducting the cytokinesis block micronucleus cytome assay. Aerobic fitness of the participants was assessed using the 6-min walking test. To investigate the effect of age on micronuclei (MN) frequency and evaluate the particular age group, our data were merged with data from a recent study by Wallner et al . (Effects of unconjugated bilirubin on chromosomal damage in individuals with Gilbert’s syndrome measured with the micronucleus cytome assay. Mutagenesis 2012; 27: 731–735). Age and MN frequency correlated significantly for squared regression ( r = 0.577; P = 0.000) and showed a levelling-off at ~60 years of age. Furthermore, we observed a significant negative linear correlation ( r = –0.222; P = 0.03) between MN frequency and 6-min walking performance. There was a plateau-like effect of the MN frequency above the age of 60–70 years, indicating a higher resistance against chromosomal damage of the ‘survivors’ of the regular lifespan. This study suggests that aerobic fitness ‘protects’ against chromosomal damage at high age.

Description: Development of novel therapeutics requires good animal models of disease. Disorders for which good animal models do not exist have very few drugs in development or clinical trial. Even where there are accepted, albeit imperfect models, the leap from promising preclinical drug results to positive clinical trials commonly fails, including in disorders of skeletal muscle. The main alternative model for early drug development, tissue culture, lacks both the architecture and, usually, the metabolic fidelity of the normal tissue in vivo . Herein, we demonstrate the feasibility and validity of human to mouse xenografts as a preclinical model of myopathy. Human skeletal muscle biopsies transplanted into the anterior tibial compartment of the hindlimbs of NOD- Rag1 null IL2r null immunodeficient host mice regenerate new vascularized and innervated myofibers from human myogenic precursor cells. The grafts exhibit contractile and calcium release behavior, characteristic of functional muscle tissue. The validity of the human graft as a model of facioscapulohumeral muscular dystrophy is demonstrated in disease biomarker studies, showing that gene expression profiles of xenografts mirror those of the fresh donor biopsies. These findings illustrate the value of a new experimental model of muscle disease, the human muscle xenograft in mice, as a feasible and valid preclinical tool to better investigate the pathogenesis of human genetic myopathies and to more accurately predict their response to novel therapeutics.

Description: Aging and its aligned loss of muscle mass are associated with higher levels of DNA damage and deteriorated antioxidant defence. To improve the body’s overall resistance against DNA damage, maintaining a healthy and active lifestyle is desirable, especially in the elderly. As people age, many have to change their residence from home living to an institution, which is often accompanied by malnutrition, depression and inactivity. The current study aimed at investigating the effect of a 6-month progressive resistance training (RT), with or without protein and vitamin supplementation (RTS), or cognitive training (CT), on DNA strand breaks in 105 Austrian institutionalised women and men (65–98 years). DNA damage was detected by performing the single cell gel electrophoresis (comet) assay. Physical fitness was assessed using the chair rise, the 6-min-walking and the handgrip strength test. In addition, antioxidant enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were analysed. Basal DNA damage (lysis) increased significantly after 3 months of intervention in the RT group (T1 – T2 + 20%, P = 0.001) and the RTS group (T1 – T2 + 17%, P = 0.002) and showed a similar tendency in the CT group (T1 – T2 + 21%, P = 0.059). %DNA in tail decreased in cells exposed to H 2 O 2 significantly in the RT (T1 – T2 – 24%, P = 0.030; T1 – T3 – 18%, P = 0.019) and CT (T1 – T2 – 21%, P = 0.004; T1 – T3 – 13%, P = 0.038) groups. Only RT and RTS groups showed significant differences overtime in enzyme activity (RT + 22% CAT-activity T1 – T3, P = 0.013; RTS + 6% SOD-activity T2 – T3, P = 0.005). Contrary to the time effects, no difference between groups was detected for any parameter at any time point. Our results suggest that both CT and RT improve resistance against H 2 O 2 induced DNA damage and that a nutritional supplement has no further protective effect in institutionalised elderly.

Description: Circulating unconjugated bilirubin (UCB) has been reported to protect against lung and colorectal cancer. The present study aimed to explore, for the first time, whether mildly elevated circulating UCB, as found in Gilbert`s syndrome (GS), is associated with changes of DNA damage. A random 76 individuals, matched for age and gender, were recruited from the general population and allocated into the GS group (UCB ≥17.1 µM; n = 38) or control group (UCB 〈17.1 µM; n = 38). Chromosomal and cytological changes were determined in lymphocytes and buccal cells using the cytokinesis-block micronucleus cytome assay (CBMN) and buccal micronucleus cytome assay (BMcyt). No significant differences were found between GS subjects and the control group in the CBMN and BMcyt determined endpoints. Subsequently, when age dependency of effects were analysed, lower formation of buccal micronucleated cells (by 73.3%) and buccal nuclear buds (by 70.9%) in the GS subgroup ≥30 years were found, compared to the GS subgroup 〈30 years. These findings suggest DNA protection in epithelial tissue of older individuals with GS.

Description: This study aimed to compare the frequencies of nuclear anomalies in buccal cells between diabetic and non-diabetic individuals and to assess the impact of a ‘healthy diet’—a cornerstone in the treatment of diabetes. Seventy-six diabetic and 21 non-diabetic individuals participated in this parallel, randomised, intervention trial. All participants received information about the importance of a healthy diet, while participants randomly assigned to the intervention group received additionally 300g of vegetables and 25ml of plant oil rich in polyunsaturated fatty acids (PUFA) per day for 8 weeks. Cytogenetic damage in buccal cells was assessed at baseline and after 8 weeks using the buccal micronucleus cytome assay. Micronucleus (MN) frequency at baseline was significantly higher in participants with diabetes (0.58±0.30) compared with non-diabetic individuals (0.28±0.29). Further analysis of baseline data revealed significantly higher MN levels in participants of the highest tertile of waist circumference (+40%), fasting plasma glucose (+55%), glycated haemoglobin (+41%) and cardiovascular disease risk (+39%) relative to participants of the lowest tertile. The dietary intervention had no effect on MN frequencies. Glycated haemoglobin and biomarkers reflecting cytokinetic defect or acute cell death were reduced in both the intervention and ‘information only’ groups. The results of this study suggest a strong impact of abdominal obesity and glucose metabolism on genomic stability. Similar effects on nuclear anomalies were observed in the ‘information only’ group and the intervention group receiving vegetables and PUFA-rich plant oil.

Description: Wood dust was classified by the IARC as a human carcinogen which causes sinonasal tumours. However, the exposure in different industries varies strongly and the risks of workers depend on the specific situation which can be assessed by the use of biomonitoring methods. The aim of this study was to investigate the workers who are exposed to low dust levels (below the permitted concentrations) with cytogenetic and biochemical methods. Micronuclei (MNi) which are indicative for genomic damage, nuclear buds which reflect gene amplification, binucleated cells which are caused by mitotic disturbances and acute cytotoxicity parameters (pyknosis, karyorrhexis, condensed chromatin, karyolysis) were monitored in buccal and nasal cells of workers of a veneer factory ( n = 51) who are exposed to volatile wood-derived compounds, in carpenters of a furniture factory which use no synthetic chemicals (n=38) and in a control group ( n = 65). Additionally, markers were measured in blood plasma which reflect inflammations (C-reactive protein, CRP) and the redox status, namely malondialdehyde (MDA) and oxidised low density proteins (oxLDL). No induction of micronucleated cells was observed in both epithelia in the two exposure groups while all other nuclear anomalies except pyknosis were increased; also one health-related biochemical marker (MDA) was significantly elevated in the workers. Taken together, the results of our study show that exposure to low levels of wood dust does not cause formation of MNi indicating that the cancer risks of the workers are not increased as a consequence of genetic damage while positive results were obtained in earlier studies with workers who are exposed to high dust levels. However, our findings indicate that wood dust causes cytotoxic effects which may lead to inflammations.