Age-related somatic structural changes in the nuclear genome of human blood cells.

Structural variations are among the most frequent interindividual genetic differences in the human genome. The frequency and distribution of de novo somatic structural variants in normal cells is, however, poorly explored. Using age-stratified cohorts of 318 monozygotic (MZ) twins and 296 single-born subjects, we describe age-related accumulation of copy-number variation in the nuclear genomes in vivo and frequency changes for both megabase- and kilobase-range variants. Megabase-range aberrations were found in 3.4% (9 of 264) of subjects ≥60 years old; these subjects included 78 MZ twin pairs and 108 single-born individuals. No such findings were observed in 81 MZ pairs or 180 single-born subjects who were ≤55 years old. Recurrent region- and gene-specific mutations, mostly deletions, were observed. Longitudinal analyses of 43 subjects whose data were collected 7-19 years apart suggest considerable variation in the rate of accumulation of clones carrying structural changes. Furthermore, the longitudinal analysis of individuals with structural aberrations suggests that there is a natural self-removal of aberrant cell clones from peripheral blood. In three healthy subjects, we detected somatic aberrations characteristic of patients with myelodysplastic syndrome. The recurrent rearrangements uncovered here are candidates for common age-related defects in human blood cells. We anticipate that extension of these results will allow determination of the genetic age of different somatic-cell lineages and estimation of possible individual differences between genetic and chronological age. Our work might also help to explain the cause of an age-related reduction in the number of cell clones in the blood; such a reduction is one of the hallmarks of immunosenescence.

Mosaic loss of chromosome Y in peripheral blood is associated with shorter survival and higher risk of cancer.

Incidence and mortality for sex-unspecific cancers are higher among men, a fact that is largely unexplained. Furthermore, age-related loss of chromosome Y (LOY) is frequent in normal hematopoietic cells, but the phenotypic consequences of LOY have been elusive. From analysis of 1,153 elderly men, we report that LOY in peripheral blood was associated with risks of all-cause mortality (hazards ratio (HR) = 1.91, 95% confidence interval (CI) = 1.17-3.13; 637 events) and non-hematological cancer mortality (HR = 3.62, 95% CI = 1.56-8.41; 132 events). LOY affected at least 8.2% of the subjects in this cohort, and median survival times among men with LOY were 5.5 years shorter. Association of LOY with risk of all-cause mortality was validated in an independent cohort (HR = 3.66) in which 20.5% of subjects showed LOY. These results illustrate the impact of post-zygotic mosaicism on disease risk, could explain why males are more frequently affected by cancer and suggest that chromosome Y is important in processes beyond sex determination. LOY in blood could become a predictive biomarker of male carcinogenesis.

Influence of red clover (Trifolium pratense) isoflavones on gene and protein expression profiles in liver of ovariectomized rats.

Isoflavones such as genistein, biochanin A, formononetin, and glycetin are fairly abundant in red clover (Trifolium pratense, Fabaceae) and show estrogenic, antioxidant and hypolipidemic activities. To explore these effects mediated by red clover extract at the gene and protein levels, female ovariectomized rats were treated with an isoflavone rich extract of T. pratense. The experimental rats were divided into 2 groups of five animals each: a) control b) experimental group (red clover extract treated with 450mg/kg/day for four days). The treatment influenced the plasma lipid levels differentially. Plasma LDL concentrations were significantly reduced (p<0.05), whereas triglycerides increased (p<0.05). Plasma HDL and total cholesterol remained unchanged. The rat livers were examined for their differential gene expression by Affymetrix Rae230 DNA microarrays. In addition, the total liver proteins were separated by 2D PAGE and proteins, which showed differences in their intensities were identified by MALDI-TOF-MS. The extract influenced the transcript levels of many novel estrogen and non-estrogen responsive genes as well as other regulatory genes. Functional annotations indicate that genes involved in metabolic pathways, information processing, membrane transport regulation, signal transduction and other cellular processes were regulated. Quantitative reverse transcription analysis with real-time PCR confirmed that red clover extract regulates genes involved in lipid metabolism and antioxidation mechanisms. Proteomic analysis support the potential of red clover extract to modulate the lipid metabolism. In summary isoflavone rich red clover extract mediates numerous genomic and non-genomic effects, which influence besides the lipid metabolism a broad range of cellular functions, including metabolic actions, cell cycle regulation and antioxidant activity.