Peripheral blood accessory cells modulate committed colony-forming units but not 5-week cobblestone-area-forming cell outgrowth from CD34+ cells

While cellular modulation in vitro of committed hematopoietic stem cell (HSC) growth has been known for some time, less is known about the effect of accessory cells (AC) on the growth of more immature HSC. We have examined the effect of peripheral blood (PB) AC on hematopoiesis by coculturing enriched PB CD34+ cells (>96% pure) with different quantities of CD34 cells (<1% contamination) harvested from 10 breast cancer patients. As expected colony growth was predominantly present in the CD34+ fractions, in which colony forming units granulocyte-macrophage (CFU-GM) varied between 89-3289/10(5) (median 1422/10(5) seeded cells) and week 5 cobblestone area forming cells (CAFC) between 64-1330/10(5) (median 427/10(5) seeded cells). Few CFU-GM (0-27/10(5) seeded cells) and no week 5 CAFC (0-1/10(5) seeded cells) were present in the CD34 fractions. The addition of PB CD34 cells to cultures of CD34+ cells resulted in a considerable variation in the cloning efficiency at the CFU-GM level, and the extent of modulation within the single patient was inconsistent between the different CD34+/CD34 cell mixtures. Overall the stimulatory effect was more pronounced than inhibition and on average the CFU-GM formation per CD34+ cell seeded increased 3 fold (stimulatory effect ranged between 3-17 fold and decreases between 2-10 fold). In contrast, the cloning efficiency at the week 5 CAFC level of differentiation remained unaffected by the addition of different amounts of CD34 cells (the stimulatory effect was maximally 3-fold and inhibition 3-fold). We conclude that while the CFU assay is modulated by the presence of AC, the CAFC assay is more robust and can be employed as a reliable and reproducible tool for HSC measurement.     

The -250G>A promoter variant in hepatic lipase associates with elevated fasting serum high-density lipoprotein cholesterol modulated by interaction with physical activity in a study of 16,156 Danish subjects

CONTEXT: Hepatic lipase plays a pivotal role in the metabolism of high-density lipoprotein (HDL) and low-density lipoprotein by involvement in reverse cholesterol transport and the formation of atherogenic small dense low-density lipoprotein. OBJECTIVES: The objective was to investigate the impact of variants in LIPC on metabolic traits and type 2 diabetes in a large sample of Danes. Because behavioral factors influence hepatic lipase activity, we furthermore examined possible gene-environment interactions in the population-based Inter99 study. DESIGN: The LIPC -250G>A (rs2070895) variant was genotyped in the Inter99 study (n = 6070), the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care Denmark screening cohort of individuals with risk factors for undiagnosed type 2 diabetes (n = 8662), and in additional type 2 diabetic patients (n = 1,064) and glucose-tolerant control subjects (n = 360). RESULTS: In the Inter99 study, the A allele of rs2070895 associated with a 0.057 mmol/liter [95% confidence interval (CI) 0.039-0.075] increase in fasting serum HDL-cholesterol (HDL-c) (P = 8 x 10(-10)) supported by association in the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care study [0.038 mmol/liter per allele (95% CI 0.024-0.053); P = 2 x 10(-7)). The allelic effect on HDL-c was modulated by interaction with self-reported physical activity (P(interaction) = 0.002) because vigorous physically active homozygous A-allele carriers had a 0.30 mmol/liter (95% CI 0.22-0.37) increase in HDL-c compared with homozygous G-allele carriers. CONCLUSIONS: We validate the association of LIPC promoter variation with fasting serum HDL-c and present data supporting an interaction with physical activity implying an increased effect on HDL-c in vigorous physically active subjects carrying the -250 A allele. This interaction may have potential implications for public health and disease prevention.     

The splicing factor SRSF6 is amplified and is an oncoprotein in lung and colon cancers

An increasing body of evidence connects alterations in the process of alternative splicing with cancer development and progression. However, a direct role of splicing factors as drivers of cancer development is mostly unknown. We analysed the gene copy number of several splicing factors in colon and lung tumours, and found that the gene encoding for the splicing factor SRSF6 is amplified and over‐expressed in these cancers. Moreover, over‐expression of SRSF6 in immortal lung epithelial cells enhanced proliferation, protected them from chemotherapy‐induced cell death and converted them to be tumourigenic in mice. In contrast, knock‐down of SRSF6 in lung and colon cancer cell lines inhibited their tumourigenic abilities. SRSF6 up‐ or down‐regulation altered the splicing of several tumour suppressors and oncogenes to generate the oncogenic isoforms and reduce the tumour‐suppressive isoforms. Our data suggest that the splicing factor SRSF6 is an oncoprotein that regulates the proliferation and survival of lung and colon cancer cells.     

Analyzing age-specific genetic effects on human extreme age survival in cohort-based longitudinal studies

The analysis of age-specific genetic effects on human survival over extreme ages is confronted with a deceleration pattern in mortality that deviates from traditional survival models and sparse genetic data available. As human late life is a distinct phase of life history, exploring the genetic effects on extreme age survival can be of special interest to evolutionary biology and health science. We introduce a non-parametric survival analysis approach that combines population survival information with individual genotype data in assessing the genetic effects in cohort-based longitudinal studies. Our approach is characterized by non-parametric analysis of late age survival to capture the observed pattern of mortality deceleration and frailty modeling to account for individual heterogeneity in unobserved frailty. The method is applied to ApoE genotype data in the Danish 1905 birth cohort to estimate effect of the e4 allele. Our results revealed an age-specific relative risk of the allele that increases nonlinearly with age and non-proportional patterns in hazard of death for carriers and non-carriers of the allele, suggesting that the e4 mutation preserves its deleterious effect that progressively affect human survival even at extreme ages.     

Combinations of self‐reported rhinitis,conjunctivitis, and asthma predicts IgE sensitization in more than 25,000 Danes

BackgroundAllergic rhinitis (AR), allergic conjunctivitis (AC), and asthma composing multiple phenotypes and improved understanding of these phenotypes and their respective risk factors are needed.ObjectivesThe objective of this study was to define the prevalence of AR, AC, and asthma and their association with allergen‐specific immunoglobulin E (sIgE) sensitization in a large cohort of blood donors and identify risk factors.MethodsFrom the nationwide population‐based Danish Blood Donor Study, 52,976 participants completed an electronic questionnaire including AR, AC, asthma, allergic predisposition, and childhood residence. Of these, 25,257 were additionally tested for sIgE to inhalation allergens (Phadiatop).ResultsThe prevalence of sIgE sensitization, AR, AC, and asthma was 30%, 19%, 15%, and 9%, respectively. The youngest birth cohorts had the highest prevalence of sIgE sensitization and symptoms of asthma, AR, and AC, and for asthma, they apparently experienced symptoms at an earlier age. The sIgE sensitization was positively associated with male sex. The sIgE seroprevalence was higher in participants with both AR and AC (ARC) than in participants with either AR or AC. Allergic predisposition and sIgE sensitization increased the risk of the diseases, while farm upbringing was associated with reduced prevalence of ARC, however, only in sIgE sensitized participants.ConclusionBirth year, childhood residence, sIgE sensitization, and allergic predisposition were associated with asthma, AR, and AC prevalence. Individuals with self‐reported ARC represent a primarily sIgE‐positive phenotype, while those with either AR or AC represent more diverse phenotypes.     

MDR1 gene expression and drug resistance of AML cells

We investigated the cellular drug resistance to aclarubicin (Acla), cytosine arabinoside (Ara-C), daunorubicin (Dau), doxorubicin (Dox), etoposide (Etop) and mitoxantrone (Mitox) using the MTT assay at time of disease presentation in 93 cases of acute myeloid leukaemia (AML). In 31 cases we concomitantly investigated MDR1 (multiple drug resistance 1 gene) expression (semi-quantitative competitive RT-PCR) of the leukaemic cells. Drug resistance towards Dau, Dox and Etop was correlated to the MDR1 expression of the AML cells ( P  < 0.05) with high MDR1 expression being associated with high drug resistance towards these drugs. Although the data did not allow firm conclusions to be drawn on the correlation between MDR1 expression and drug resistance towards Ara-C and Mitox, the drug resistance towards Acla clearly was not correlated to, or dependent on, the MDR1 expression level of the AML blast cells. In addition, when examining the cross-activities among the six drugs distinct patterns emerged. Thus, high to very high degrees of cross-activity were found to exist between Dau, Dox, Etop and Mitox, whereas Ara-C had moderate cross-activity with the other drugs except Acla, which showed absent to moderate cross-activity with the other drugs. We conclude that MDR1 gene expression is of significance for cellular drug resistance towards specific (MDR1-related) drugs in AML, whereas it is not of significance regarding drug resistance towards other drugs, which is the case with the anthracycline Acla. We suggest that in the place of other more or less complicated ways to circumvent MDR1-mediated drug resistance, Acla may be used to replace Dau, Dox and other MDR1-related drugs if proven as potent as the drug it is to substitute.     

Risk of Recurrent Venous Thromboembolism: A Danish Nationwide Cohort Study

Purpose

In this study, we aimed to estimate recurrence risk after incident venous thromboembolism, stratified according to unprovoked, provoked, and cancer-related venous thromboembolism in a prospective cohort of inpatients and outpatients receiving routine care.