Sleep Duration, Health Promotion Index, sRAGE, and ApoE-ε4 Genotype Are Associated With Telomere Length in Healthy Australians.

Significant alterations in sleep duration and/or quality of sleep become more pronounced as people get older. Poor sleep in elderly people is associated with adverse health outcomes and cellular aging. We examined the relationship between telomere length (TL) and sleep duration, Health Promotion Index (HPI), and tested whether the presence of Apolipoprotein-E4 (ApoE-ε4) allele affects both sleep and TL. The present study was carried out in 174 healthy participants (21% male; mean age 53.79 years) from South Australia. Lymphocyte TL was measured by real-time quantitative PCR (qPCR) and ApoE genotype was determined by TaqMan assay. HPI was calculated from a questionnaire regarding 8 lifestyle habits, including sleeping hours. Multivariate regression analysis was used to establish these associations adjusted for specified confounders. TL was found to be inversely associated with age (r = -0.199; p = .008) and body mass index (r = -0.121; p = .11), and was significantly shorter in participants who slept for less than 7 hours (p = .001) relative to those sleeping ≥7 hours. TL was positively correlated with HPI (r = 0.195; p = .009). ApoE-ε4 allele carriers who slept for less than 7 hours had shortest TL (p = .01) compared to noncarriers. Plasma soluble receptor for advanced glycation end product (sRAGE) level was significantly (p = .001) lower in individuals who sleep less than 7 hours and ApoE-ε4 carriers. Our results suggest that inadequate sleep duration or poor HPI is associated with shorter TL in cognitively normal people and that carriage of APOE-ε4 genotype may influence the extent of these effects.

Telomere Length in Healthy Adults Is Positively Associated With Polyunsaturated Fatty Acids, Including Arachidonic Acid, and Negatively With Saturated Fatty Acids.

Lymphocyte telomere length (LTL) is a biomarker of aging that may be modified by dietary factors including fat. Red blood cell fatty acid status is a well-validated indicator of long-term dietary intake of fat from various sources. Recent findings from epidemiological studies of LTL in relation to fatty acids in red blood cells are not conclusive. The present study was carried out to investigate if red blood cell fatty acid status in 174 healthy older South Australians is associated with LTL. Lymphocyte telomere length was measured by real-time qPCR and fatty acid content in red blood cells was measured by gas chromatography. Our results indicate that the majority of saturated fatty acids and monounsaturated fatty acids are negatively associated with LTL, whereas polyunsaturated fatty acids are positively associated with LTL. Multiple regression analysis revealed that arachidonic acid (C20:4n-6) is significantly, independently, positively correlated with LTL (ß = 0.262; p = .000). The significant association of fatty acids, particularly C20:4n-6, with telomere length warrants further research.

Shorter Telomere Length in Carriers of APOE-ε4 and High Plasma Concentration of Glucose, Glyoxal and Other Advanced Glycation End Products (AGEs).

Apolipoprotein-ε4 (APOE-ε4)-common variant is a major genetic risk factor for cognitive decline and Alzheimer's disease (AD). An accelerated rate of biological aging could contribute to this increased risk. Glycation of serum proteins due to excessive glucose and reactive oxygen species leads to the formation of advanced glycation end products (AGEs)-a risk factor for diabetes and AD, and decline in motor functioning in elderly adults. Aim of present study was to investigate impact of APOE-ε4 allele containing genotype and accumulation of AGEs in plasma on telomere length (TL). Results showed that TL is significantly shorter in APOE-ε4 carriers compared with non-APOE-ε4 carriers (p = .0003). Higher plasma glucose level was associated with shorter TL irrespective of APOE-ε4 allele containing genotype (r = -.26; p = .0004). With regard to AGEs, higher plasma glyoxal and fluorescent AGEs concentrations were inversely related to TL (r = -.16; p = .03; r = -.28; p = .0001), however, plasma Nε-(carboxymethyl)lysine levels didn't correlate with TL (r = -.04; p = .57). Results support the hypotheses that APOE-ε4 carriers have shorter telomeres than noncarriers and telomere erosion is increased with higher concentration of glucose, fluorescent AGEs, and glyoxal.

APOE ε4 Carriers Have a Greater Propensity to Glycation and sRAGE Which Is Further Influenced by RAGE G82S Polymorphism.

APOE ε4 allele is an established risk factor for Alzheimer's disease and hypercholesterolemia. However, its association with metabolic and genetic risk factors related to glycation is not clear. We tested the hypothesis that, apart from high plasma cholesterol, APOE ε4 carriers may also have higher advanced glycation end products (AGEs) and total soluble extracellular domain of RAGE (sRAGE) and that these biomarkers may be modified by the common Gly82Ser (G82S) polymorphism (rs2070600) in the RAGE gene. To test this, we measured these biomarkers in 172 healthy cognitively normal individuals, of which 32 were APOE ε4 carriers and 140 noncarriers. APOE ε4 carriers showed higher levels of cholesterol (p < .001), glyoxal (p < .001), fluorescent AGEs (p < .001), Nε-carboxymethyllysine (p < .001) and sRAGE (p = .018) when compared to noncarriers. Furthermore, sRAGE was also higher in those that did not carry the A allele of the RAGE gene that codes for serine instead of glycine (p = .034). Our study indicates that APOE ε4 carriers have a greater propensity to glycation than noncarriers which may further increase their risk for diabetes and dementia. The increased sRAGE levels in APOE ε4 carriers suggests a defensive response against AGEs that may be further influenced by the RAGE G82S polymorphism.

Chromosomal DNA damage in APOE ɛ4 carriers and noncarriers does not appear to be different.

DNA damage may play a key role in promoting disease-onset and accelerated disease progression in Alzheimer's disease (AD) by increasing the rates of neuronal cell death. The ɛ4 allele of the APOE gene is the best characterised genetic risk factor for AD, however, it is unknown if APOE ɛ4 carriers exhibit increased levels of DNA damage which may contribute to increased AD risk. 175 healthy participants (aged 34-67 years old) from South Australia were recruited into the study and provided a single blood sample for the isolation of peripheral blood lymphocytes, APOE genotyping and lymphocyte chromosomal DNA damage analysis using the Cytokinesis-Block micronucleus cytome (CBMN-Cyt) assay with the micronucleus index being the primary outcome measure. When compared to non-APOE ɛ4 carriers, APOE ɛ4 carriers did not exhibit altered rates of i) cell division, represented by the nuclear division index (NDI, P = 0.372), ii) cell death as represented by apoptotic (P = 0.457) and necrotic (P = 0.393) frequencies and iii) chromosomal DNA damage as indicated by the number of micronuclei (MNi, P = 0.795), nucleoplasmic bridges (NPBs, P = 0.221) or nuclear buds (NBUDs, P = 0.293) scored in binucleated cells. In conclusion, although we and others have previously shown that rates of chromosomal DNA damage measured using the CBMN-Cyt assay are elevated in individuals with cognitive impairment, in this South Australian cohort the frequency of genome instability is not substantially influenced by the presence of the APOE ɛ4 allele.

Effect of docosahexaenoic acid and furan fatty acids on cytokinesis block micronucleus cytome assay biomarkers in astrocytoma cell lines under conditions of oxidative stress.

Fatty acids from fish such as docosahexaenoic acid (DHA) are associated with improved brain function, whereas furan fatty acids (FFAs) also found in fish oil at low levels (1%) are thought to have antioxidant properties. Understanding their effects in astrocytes is important as these cells are responsible for maintaining healthy neurons via lipid homeostasis and distribution within the brain, and their decline with aging is a possible cause of dementia. We investigated the cytotoxic and genotoxic effects of DHA and FFA using the cytokinesis-block micronucleus cytome assay in in vitro cultures of U87MG (APOE ɛ3/ɛ3) and U118MG (APOE ɛ2/ɛ4) astrocytoma cell lines with and without a hydrogen peroxide (H2O2, 100 µM) challenge. U118MG was found to be more sensitive to the cytostatic, cytotoxic (i.e., apoptosis), and DNA damaging effects [micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs)] of H2O2 (P < 0.01 and P < 0.001) when compared with U87MG. DHA at 100 µg/mL significantly affected cytostasis (P < 0.05) and increased DNA damage in the form of NPBs and MNi (P < 0.05) in both cell lines, whereas it decreased necrosis (P = 0.0251) in U87MG. Significant DHA-H2O2 interactions were observed for decreased necrosis (P = 0.0033) and DNA damage biomarkers (P < 0.0001) in the U87MG cell line and increased cytostasis (P < 0.0001) in the U118MG cell line. The effects of FFA also varied between the cell lines, with significant effects observed in decreased cytostasis (P = 0.0022) in the U87MG cell line, whereas increasing cytostasis (P = 0.0144) in the U118MG cell line. Overall, FFA exerted minimal effects on DNA damage biomarkers.

Probiotic factors partially prevent changes to caspases 3 and 7 activation and transepithelial electrical resistance in a model of 5-fluorouracil-induced epithelial cell damage.

The potential efficacy of a probiotic-based preventative strategy against intestinal mucositis has yet to be investigated in detail. We evaluated supernatants (SN) from Escherichia coli Nissle 1917 (EcN) and Lactobacillus rhamnosus GG (LGG) for their capacity to prevent 5-fluorouracil (5-FU)-induced damage to intestinal epithelial cells. A 5-day study was performed. IEC-6 cells were treated daily from days 0 to 3, with 1 mL of PBS (untreated control), de Man Rogosa Sharpe (MRS) broth, tryptone soy roth (TSB), LGG SN, or EcN SN. With the exception of the untreated control cells, all groups were treated with 5-FU (5 µM) for 24 h at day 3. Transepithelial electrical resistance (TEER) was determined on days 3, 4, and 5, while activation of caspases 3 and 7 was determined on days 4 and 5 to assess apoptosis. Pretreatment with LGG SN increased TEER (p < 0.05) compared to controls at day 3. 5-FU administration reduced TEER compared to untreated cells on days 4 and 5. Pretreatment with MRS, LGG SN, TSB, and EcN SN partially prevented the decrease in TEER induced by 5-FU on day 4, while EcN SN also improved TEER compared to its TSB vehicle control. These differences were also observed at day 5, along with significant improvements in TEER in cells treated with LGG and EcN SN compared to healthy controls. 5-FU increased caspase activity on days 4 and 5 compared to controls. At day 4, cells pretreated with MRS, TSB, LGG SN, or EcN SN all displayed reduced caspase activity compared to 5-FU controls, while both SN groups had significantly lower caspase activity than their respective vehicle controls. Caspase activity in cells pretreated with MRS, LGG SN, and EcN SN was also reduced at day 5, compared to 5-FU controls. We conclude that pretreatment with selected probiotic SN could prevent or inhibit enterocyte apoptosis and loss of intestinal barrier function induced by 5-FU, potentially forming the basis of a preventative treatment modality for mucositis.

Impact of KRAS and BRAF Gene Mutation Status on Outcomes From the Phase III AGITG MAX Trial of Capecitabine Alone or in Combination With Bevacizumab and Mitomycin in Advanced Colorectal Cancer.

PURPOSE: Mutations affecting the KRAS gene are established predictive markers of outcome with anti-epithelial growth factor receptor (EGFR) antibodies in advanced colorectal cancer (CRC). The relevance of these markers for anti-vascular endothelial growth factor (VEGF) therapy is controversial. This analysis was performed to assess the predictive and prognostic impact of KRAS and BRAF gene mutation status in patients receiving capecitabine with bevacizumab (CG) or capecitabine without bevacizumab in the phase III AGITG MAX (Australasian Gastrointestinal Trials Group MAX) study. PATIENTS AND METHODS: Mutation status was determined for 315 (66.9%) of the original 471 patients. Mutation status was correlated with efficacy outcomes (response rate, progression-free survival [PFS], and overall survival [OS]), and a predictive analyses was undertaken. RESULTS: Mutations in KRAS and BRAF genes were observed in 28.8% and 10.6% of patients, respectively. KRAS gene mutation status (wild type [WT] v mutated [MT]) had no prognostic impact for PFS (hazard ratio [HR], 0.89; CI, 0.69 to 1.14) or OS (HR, 0.97; CI, 0.73 to 1.28). BRAF mutation status (WT v MT) was not prognostic for PFS (HR, 0.80; CI, 0.54 to 1.18) but was prognostic for OS (HR, 0.49; CI, 0.33 to 0.73; P = .001). By using the comparison of capecitabine versus capecitabine and bevacizumab (CB) and CB plus mitomycin (CBM), KRAS gene mutation status was not predictive of the effectiveness of bevacizumab for PFS or OS (test for interaction P = .95 and 0.43, respectively). Similarly, BRAF gene mutation status was not predictive of the effectiveness of bevacizumab for PFS or OS (test for interaction P = .46 and 0.32, respectively). CONCLUSION: KRAS gene mutation status was neither prognostic for OS nor predictive of bevacizumab outcome in patients with advanced CRC. BRAF gene mutation status was prognostic for OS but was not predictive of outcome with bevacizumab.