Consumption of a low glycaemic index diet in late life extends lifespan of Balb/c mice with differential effects on DNA damage

Background : Caloric restriction is known to extend the lifespan of all organisms in which it has been tested. Consequently, current research is investigating the role of various foods to improve health and lifespan. The role of various diets has received less attention however, and in some cases may have more capacity to improve health and longevity than specific foods alone. We examined the benefits to longevity of a low glycaemic index (GI) diet in aged Balb/c mice and examined markers of oxidative stress and subsequent effects on telomere dynamics.

Results : In an aged population of mice, a low GI diet extended average lifespan by 12%, improved glucose tolerance and had impressive effects on amelioration of oxidative damage to DNA in white blood cells. Telomere length in quadriceps muscle showed no improvement in the dieted group, nor was telomerase reactivated.

Conclusion : The beneficial effects of a low GI diet are evident from the current study and although the impact to telomere dynamics late in life is minimal, we expect that earlier intervention with a low GI diet would provide significant improvement in health and longevity with associated effects to telomere homeostasis.

Oiling the brain : a review of randomized controlled trials of omega-3 fatty acids in psychopathology across the lifespan

Around one in four people suffer from mental illness at some stage in their lifetime. There is increasing awareness of the importance of nutrition, particularly omega-3 polyunsaturated fatty acids (n-3 PUFA), for optimal brain development and function. Hence in recent decades, researchers have explored effects of n-3 PUFA on mental health problems over the lifespan, from developmental disorders in childhood, to depression, aggression, and schizophrenia in adulthood, and cognitive decline, dementia and Alzheimer’s disease in late adulthood. This review provides an updated overview of the published and the registered clinical trials that investigate effects of n-3 PUFA supplementation on mental health and behavior, highlighting methodological differences and issues.

Dose-dependent effects of docosahexaenoic acid-rich fish oil on erythrocyte docosahexaenoic acid and blood lipid levels

Consumption of long-chain n-3 PUFA, particularly DHA, has been shown to improve cardiovascular risk factors but the intake required to achieve benefits is unclear. We sought to determine the relationship between DHA intake, increases in erythrocyte DHA content and changes in blood lipids. A total of sixty-seven subjects (thirty-six male, thirty-one female, mean age 53 years) with fasting serum TAG ≥ 1·1 mmol/l and BMI>25 kg/m² completed a 12-week, randomized, double-blind, placebo-controlled parallel intervention. Subjects consumed 2, 4 or 6 g/d of DHA-rich fish oil (26 % DHA, 6 % EPA) or a placebo (Sunola oil). Fasting blood lipid concentrations and fatty acid profiles in erythrocyte membranes were assessed at baseline and after 6 and 12 weeks. For every 1 g/d increase in DHA intake, there was a 23 % reduction in TAG (mean baseline concentration 1·9 (sem 0·1) mmol/l), 4·4 % increase in HDL-cholesterol and 7·1 % increase in LDL-cholesterol. Erythrocyte DHA content increased in proportion to the dose of DHA consumed (r 0·72, P < 0·001) and the increase after 12 weeks was linearly related to reductions in TAG (r − 0·38, P < 0·01) and increases in total cholesterol (r 0·39, P < 0·01), LDL-cholesterol (r 0·33, P < 0·01) and HDL-cholesterol (r 0·30, P = 0·02). The close association between incorporation of DHA in erythrocytes and its effects on serum lipids highlights the importance of erythrocyte DHA as an indicator of cardiovascular health status.

A mixed blessing of lifespan heterogeneity

Human mortality data reveal that life expectancy in industrialized countries has been converging to a common value. Yet, significant variations in the distributions of adult life-table ages at death among some developed countries have also been observed. This paper, largely motivated by Japan’s mortality data, presents a general equilibrium, overlapping-generations model that assesses the welfare effects of the mean-preserving declines in the variance of the distribution of adult ages at death. Our quantitative exercise reveals that for a given value of the economy-wide life expectancy, the individual welfare effects due to switching from high to low-variance steady states are length of life-dependent, quite sensitive to the average economy-wide retirement age, and strongly influenced by associated changes in the labor supply, factor prices, and lifetime earnings.

Nutrients, not caloric restriction, extend lifespan in Queensland fruit flies (Bactrocera tryoni)

Caloric restriction (CR) has been widely accepted as a mechanism explaining increased lifespan (LS) in organisms subjected to dietary restriction (DR), but recent studies investigating the role of nutrients have challenged the role of CR in extending longevity. Fuelling this debate is the difficulty in experimentally disentangling CR and nutrient effects due to compensatory feeding (CF) behaviour. We quantified CF by measuring the volume of solution imbibed and determined how calories and nutrients influenced LS and fecundity in unmated females of the Queensland fruit fly, Bactocera tryoni (Diptera: Tephritidae). We restricted flies to one of 28 diets varying in carbohydrate:protein (C:P) ratios and concentrations. On imbalanced diets, flies overcame dietary dilutions, consuming similar caloric intakes for most dilutions. The response surface for LS revealed that increasing C:P ratio while keeping calories constant extended LS, with the maximum LS along C:P ratio of 21:1. In general, LS was reduced as caloric intake decreased. Lifetime egg production was maximized at a C:P ratio of 3:1. When given a choice of separate sucrose and yeast solutions, each at one of five concentrations (yielding 25 choice treatments), flies regulated their nutrient intake to match C:P ratio of 3:1. Our results (i) demonstrate that CF can overcome dietary dilutions; (ii) reveal difficulties with methods presenting fixed amounts of liquid diet; (iii) illustrate the need to measure intake to account for CF in DR studies and (iv) highlight nutrients rather than CR as a dominant influence on LS.

Short telomeres in hatching snakes : erythrocyte telomere dynamics and longevity in tropical pythons

Telomere length (TL) has been found to be associated with life span in birds and humans. However, other studies have demonstrated that TL does not affect survival among old humans. Furthermore, replicative senescence has been shown to be induced by changes in the protected status of the telomeres rather than the loss of TL. In the present study we explore whether age- and sex-specific telomere dynamics affect life span in a long-lived snake, the water python (Liasis fuscus).

Erythrocyte ghost cell-alkaline phosphatase: construction and characterization of a vesicular system for use in biomineralization studies

Alkaline phosphatase is required for the mineralization of bone and cartilage. This enzyme is localized in the matrix vesicle, which plays a role key in calcifying cartilage. In this paper we standardize a method to construction a resealed ghost cell-alkaline phosphatase system to mimic matrix vesicles and examine the kinetic behavior of the incorporated enzyme. Polidocanol-solubilized alkaline phosphatase, free of detergent, was incorporated into resealed ghost cells. This process was time-dependent and practically 50% of the enzyme was incorporated into the vesicles in 40 h of incubation, at 25 degreesC. Alkaline phosphatase-ghost cell systems were relatively homogeneous with diameters of about 300 nm and were more stable when stored at -20 degreesC.Alkaline phosphatase was completely released from the resealed ghost cell-system using only phospholipase C. These experiments confirm that the interaction between alkaline phosphatase and the lipid bilayer of resealed ghost cell is exclusively via glycosylphosphatidylinositol (GPI) anchor of the enzyme.An important point shown is that an enzyme bound to resealed ghost cell does not lose the ability to hydrolyze ATP, pyrophosphate and p-nitrophenyl phosphate (PNPP), but the presence of a ghost membrane, as a support of the enzyme, affects its kinetic properties. Moreover, calcium ions stimulate and phosphate ions inhibit the PNPPase activity of alkaline phosphatase present in resealed ghost cells. (C) 2002 Elsevier B.V. B.V. All rights reserved.

eNOS T-786C polymorphism affects atorvastatin-induced changes in erythrocyte membrane fluidity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Flow cytometric assessment of canine erythrocytes and platelets for dog erythrocyte antigen 1.1

Background: In human medicine, transfusion of ABO-mismatched platelets has been associated with shortened platelet survival and refractoriness to platelet transfusion because of expression of certain blood group antigens on platelets. It remains unknown if canine platelets express dog erythrocyte antigens (DEAs). Objective: The aim of this study was to develop a flow cytometric assay for DEA 1.1 and determine whether DEA 1.1 is present on canine platelets.Methods: Blood was collected from 172 clinically healthy dogs. Platelets and erythrocytes from each dog were tested for DEA 1.1 by flow cytometry using anti-DEA 1.1 blood-typing sera. Erythrocytes from each dog were also assessed for DEA 1.1 using a standard tube-typing test (T1) and using a second tube method (T2), if the flow cytometric and T1 results differed.Results: Using flow cytometry, DEA 1.1 was detected on erythrocytes of all 110 dogs shown by T1 or T2 testing to be DEA 1.1-positive. Initial results of the T1 test had a diagnostic accuracy of 93% (160 correct/ 172 tests). The frequency of erythrocyte DEA 1.1 positivity in previously untyped dogs (n = 118) was 56%. DEA 1.1 expression was not detected on platelets from DEA 1.1-positive dogs.Conclusions: Flow cytometry was a reliable method for detection of DEA 1.1 on canine erythrocytes. The absence of DEA 1.1 on platelets from DEA 1.1-positive dogs suggests that their platelets do not express DEA 1.1 and will not induce production of anti-DEA 1.1 antibodies that might lead to platelet refractoriness or reactions to a subsequent transfusion of DEA 1.1positive erythrocytes.

Effect of progesterone and/or estradiol treatments prior to induction of ovulation on subsequent luteal lifespan in anestrous Nelore cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)