Restricted diet delays accelerated ageing and genomic stress in DNA-repair-deficient mice.

Mice deficient in the DNA excision-repair gene Ercc1 (Ercc1∆/-) show numerous accelerated ageing features that limit their lifespan to 4-6 months. They also exhibit a 'survival response', which suppresses growth and enhances cellular maintenance. Such a response resembles the anti-ageing response induced by dietary restriction (also known as caloric restriction). Here we report that a dietary restriction of 30% tripled the median and maximal remaining lifespans of these progeroid mice, strongly retarding numerous aspects of accelerated ageing. Mice undergoing dietary restriction retained 50% more neurons and maintained full motor function far beyond the lifespan of mice fed ad libitum. Other DNA-repair-deficient, progeroid Xpg-/- (also known as Ercc5-/-) mice, a model of Cockayne syndrome, responded similarly. The dietary restriction response in Ercc1∆/- mice closely resembled the effects of dietary restriction in wild-type animals. Notably, liver tissue from Ercc1∆/- mice fed ad libitum showed preferential extinction of the expression of long genes, a phenomenon we also observed in several tissues ageing normally. This is consistent with the accumulation of stochastic, transcription-blocking lesions that affect long genes more than short ones. Dietary restriction largely prevented this declining transcriptional output and reduced the number of γH2AX DNA damage foci, indicating that dietary restriction preserves genome function by alleviating DNA damage. Our findings establish the Ercc1∆/- mouse as a powerful model organism for health-sustaining interventions, reveal potential for reducing endogenous DNA damage, facilitate a better understanding of the molecular mechanism of dietary restriction and suggest a role for counterintuitive dietary-restriction-like therapy for human progeroid genome instability syndromes and possibly neurodegeneration in general.

Effects of bariatric surgery on telomere length and T-cell aging.

BACKGROUND: Obesity adversely affects health and is associated with subclinical systemic inflammation and features of accelerated aging, including the T-cell immune system. The presence of metabolic syndrome (MetS) may accelerate, while bariatric surgery might reverse these phenomena. To examine the effects of MetS and bariatric surgery on T-cell aging, we measured relative telomere length (RTL) and T-cell differentiation status in obese patients before and after bariatric surgery. METHODS: WHO II/III classified obese patients scheduled for bariatric surgery were included: 41 without MetS and 67 with MetS. RTL and T-cell differentiation status were measured in circulating CD4+ and CD8+ T cells via flow cytometry. T-cell characteristics were compared between patients with and without MetS prior to and at 3, 6, and 12 months after surgery considering effects of age, cytomegalovirus-serostatus, and weight loss. RESULTS: Thymic output, represented by numbers of CD31-expressing naive T cells, showed an age-related decline in patients with MetS. MetS significantly enhanced CD8+ T-cell differentiation. Patients with MetS had significant lower CD4+ RTL than patients without MetS. Within the first 6 months after bariatric surgery, RTL increased in CD4+ T cells after which it decreased at month 12. A decline in both thymic output and more differentiated T cells was seen following bariatric surgery, more pronounced in the MetS group and showing an association with percentage of body weight loss. CONCLUSIONS: In obese patients, MetS results in attrition of RTL and accelerated T-cell differentiation. Bariatric surgery temporarily reverses these effects. These data suggest that MetS is a risk factor for accelerated aging of T cells and that MetS should be a more prominent factor in the decision making for eligibility for bariatric surgery.

Programming of metabolic effects in C57BL/6JxFVB mice by in utero and lactational exposure to perfluorooctanoic acid.

Perfluorooctanoic acid (PFOA) is known to cause developmental toxicity and is a suggested endocrine disrupting compound (EDC). Early life exposure to EDCs has been implicated in programming of the developing organism for chronic diseases later in life. Here we study perinatal metabolic programming by PFOA using an experimental design relevant for human exposure. C57BL/6JxFVB hybrid mice were exposed during gestation and lactation via maternal feed to seven low doses of PFOA at and below the NOAEL used for current risk assessment (3-3000 µg/kg body weight/day). After weaning, offspring were followed for 23-25 weeks without further exposure. Offspring showed a dose-dependent decrease in body weight from postnatal day 4 to adulthood. Growth under high fat diet in the last 4-6 weeks of follow-up was increased in male and decreased in female offspring. Both sexes showed increased liver weights, hepatic foci of cellular alterations and nuclear dysmorphology. In females, reductions in perigonadal and perirenal fat pad weights, serum triglycerides and cholesterol were also observed. Endocrine parameters, such as glucose tolerance, serum insulin and leptin, were not affected. In conclusion, our study with perinatal exposure to PFOA in mice produced metabolic effects in adult offspring. This is most likely due to disrupted programming of metabolic homeostasis, but the assayed endpoints did not provide a mechanistic explanation. The BMDL of the programming effects in our study is below the current point of departure used for calculation of the tolerable daily intake.

Compound- and sex-specific effects on programming of energy and immune homeostasis in adult C57BL/6JxFVB mice after perinatal TCDD and PCB 153.

Early life exposure to endocrine disrupting compounds has been linked to chronic diseases later in life, like obesity and related metabolic disorders. We exposed C57BL/6JxFVB hybrid mice to the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the constitutive androstane receptor/pregnane X receptor agonist polychlorinated biphenyl 153 (PCB 153) in an experimental design relevant for human exposure. Exposure occurred during gestation and lactation via maternal feed to a wide dose range (TCDD: 10-10,000 pg/kg body weight/day; PCB 153: 0.09-1406 µg/kg body weight/d). Then exposure was ceased and offspring were followed up to 1 year of age. Metabolic parameters like body weight, fat pad weights, glucose tolerance, endocrine serum profile, and neurobehavioral and immunological parameters were determined. Body weight was transiently affected by both compounds throughout the follow-up. TCDD-exposed males showed decreased fat pad and spleen weights and an increase in IL-4 production of splenic immune cells. In contrast, females showed increased fat pad weights and production of IFNγ. PCB 153-exposed males showed an increase in glucose, whereas females showed an increase in glucagon, a decrease in pancreas weight, and an increase in thymus weight. In conclusion, early life exposure to TCDD appears to affect programming of energy and immune homeostasis in offspring, whereas the effects of perinatal PCB 153 were mainly on programming of glucose homeostasis. Both compounds act sex-specifically. Lowest derived BMDLs (lower bounds of the (two sided) 90%-confidence interval for the benchmark dose) for both compounds are not lower than current tolerable daily intakes.

Lifestyle factors and metabolomic aging biomarkers: Meta-analysis of cross-sectional and longitudinal associations in three prospective cohorts.

Biological age uses biophysiological information to capture a person's age-related risk of adverse outcomes. MetaboAge and MetaboHealth are metabolomics-based biomarkers of biological age trained on chronological age and mortality risk, respectively. Lifestyle factors contribute to the extent chronological and biological age differ. The association of lifestyle factors with MetaboAge and MetaboHealth, potential sex differences in these associations, and MetaboAge's and MetaboHealth's sensitivity to lifestyle changes have not been studied yet. Linear regression analyses and mixed-effect models were used to examine the cross-sectional and longitudinal associations of scaled lifestyle factors with scaled MetaboAge and MetaboHealth in 24,332 middle-aged participants from the Doetinchem Cohort Study, Rotterdam Study, and UK Biobank. Random-effect meta-analyses were performed across cohorts. Repeated metabolomics measurements had a ten-year interval in the Doetinchem Cohort Study and a five-year interval in the UK Biobank. In the first study incorporating longitudinal information on MetaboAge and MetaboHealth, we demonstrate associations between current smoking, sleeping ≥8 hours/day, higher BMI, and larger waist circumference were associated with higher MetaboHealth, the latter two also with higher MetaboAge. Furthermore, adhering to the dietary and physical activity guidelines were inversely associated with MetaboHealth. Lastly, we observed sex differences in the associations between alcohol use and MetaboHealth.

Self-rated health in individuals with and without disease is associated with multiple biomarkers representing multiple biological domains.

Self-rated health (SRH) is one of the most frequently used indicators in health and social research. Its robust association with mortality in very different populations implies that it is a comprehensive measure of health status and may even reflect the condition of the human organism beyond clinical diagnoses. Yet the biological basis of SRH is poorly understood. We used data from three independent European population samples (N approx. 15,000) to investigate the associations of SRH with 150 biomolecules in blood or urine (biomarkers). Altogether 57 biomarkers representing different organ systems were associated with SRH. In almost half of the cases the association was independent of disease and physical functioning. Biomarkers weakened but did not remove the association between SRH and mortality. We propose three potential pathways through which biomarkers may be incorporated into an individual's subjective health assessment, including (1) their role in clinical diseases; (2) their association with health-related lifestyles; and (3) their potential to stimulate physical sensations through interoceptive mechanisms. Our findings indicate that SRH has a solid biological basis and it is a valid but non-specific indicator of the biological condition of the human organism.

Glucose levels and genetic variants across transcriptional pathways: interaction effects with BMI.

OBJECTIVE: Much of the genetic variation in glucose levels remains to be discovered. Especially, research on gene-environment interactions is scarce. Overweight is one of the main risk factors for hyperglycemia. As transcriptional regulation is important for both weight maintenance and glucose control, we analyzed 353 single nucleotide polymorphisms (SNPs), occurring in transcriptional pathways of glucose and lipid metabolism in interaction with body mass index (BMI) on glucose levels. RESEARCH DESIGN AND METHODS: SNPs were measured in 3244 participants of the Doetichem cohort. Non-fasting glucose levels and BMI were measured twice in 6 years. SNP x BMI interactions were analyzed by mixed models and adjusted for age, sex, time since last meal, and follow-up time. False discovery rate (FDR) <0.2 was used to adjust for multiple testing. RESULTS: Two SNPs in the PPARGC1A gene (rs8192678, FDR=0.07; rs3755863, FDR=0.17) showed a significant interaction with BMI. The rare allele of both SNPs was associated with significantly lower glucose levels in subjects with a BMI28 kg m(-2). A small intervention study (n=120) showed similar, though non-significant, results. CONCLUSIONS: Using a pathway-based approach, we found that BMI significantly modified the association between two SNPs in the PPARGC1A gene and glucose levels. The association between glucose and PPARGC1A was only present in lean subjects. This suggests that the effect of the PPARGC1A gene, which is involved both in fatty acid oxidation and glucose metabolism, is modified by BMI.

Genetic variations in regulatory pathways of fatty acid and glucose metabolism are associated with obesity phenotypes: a population-based cohort study.

BACKGROUND: As nuclear receptors and transcription factors have an important regulatory function in adipocyte differentiation and fat storage, genetic variation in these key regulators and downstream pathways may be involved in the onset of obesity. OBJECTIVE: To explore associations between single nucleotide polymorphisms (SNPs) in candidate genes from regulatory pathways that control fatty acid and glucose metabolism, and repeated measurements of body mass index (BMI) and waist circumference in a large Dutch study population. METHODS: Data of 327 SNPs across 239 genes were analyzed for 3575 participants of the Doetinchem cohort, who were examined three times during 11 years, using the Illumina Golden Gate assay. Adjusted random coefficient models were used to analyze the relationship between SNPS and obesity phenotypes. False discovery rate q-values were calculated to account for multiple testing. Significance of the associations was defined as a q-value < or = 0.20. RESULTS: Two SNPs (in NR1H4 and SMARCA2 in women only) were significantly associated with both BMI and waist circumference. In addition, two SNPs (in SIRT1 and SCAP in women only) were associated with BMI alone. A functional SNP, in IL6, was strongly associated with waist. CONCLUSION: In this explorative study among participants of a large population-based cohort, five SNPs, mainly located in transcription mediator genes, were strongly associated with obesity phenotypes. The results from whole genome and candidate gene studies support the potential role of NR1H4, SIRT1, SMARCA2 and IL6 in obesity. Although replication of our findings and further research on the functionality of these SNPs and underlying mechanism is necessary, our data indirectly suggest a role of GATA transcription factors in weight control.

The Association between BMI and Different Frailty Domains: A U-Shaped Curve?

OBJECTIVES: Previous studies showed a U-shaped association between BMI and (physical) frailty. We studied the association between BMI and physical, cognitive, psychological, and social frailty. Furthermore, the overlap between and prevalence of these frailty domains was examined. DESIGN: Cross-sectional study. SETTING: The Doetinchem Cohort Study is a longitudinal population-based study starting in 1987-1991 examining men and women aged 20-59 with follow-up examinations every 5 yrs. PARTICIPANTS: For the current analyses, we used data from round 5 (2008-2012) with 4019 participants aged 41-81 yrs. MEASUREMENTS: Physical frailty was defined as having ≥ 2 of 4 frailty criteria from the Frailty Phenotype (unintentional weight loss, exhaustion, physical activity, handgrip strength). Cognitive frailty was defined as the < 10th percentile on global cognitive functioning (based on memory, speed, flexibility). Psychological frailty was defined as having 2 out of 2 criteria (depression, mental health). Social frailty was defined as having ≥ 2 of 3 criteria (loneliness, social support, social participation). BMI was divided into four classes. Analyses were adjusted for sex, age, level of education, and smoking. RESULTS: A U-shaped association was observed between BMI and physical frailty, a small linear association for BMI and cognitive frailty and no association between BMI and psychological and social frailty. The four frailty domains showed only a small proportion of overlap. The prevalence of physical, cognitive and social frailty increased with age, whereas psychological frailty did not. CONCLUSION: We confirm that not only underweight but also obesity is associated with physical frailty. Obesity also seems to be associated with cognitive frailty. Further, frailty prevention should focus on multiple domains and target individuals at a younger age (<65yrs).

A signature of renal stress resistance induced by short-term dietary restriction, fasting, and protein restriction.

During kidney transplantation, ischemia-reperfusion injury (IRI) induces oxidative stress. Short-term preoperative 30% dietary restriction (DR) and 3-day fasting protect against renal IRI. We investigated the contribution of macronutrients to this protection on both phenotypical and transcriptional levels. Male C57BL/6 mice were fed control food ad libitum, underwent two weeks of 30%DR, 3-day fasting, or received a protein-, carbohydrate- or fat-free diet for various periods of time. After completion of each diet, renal gene expression was investigated using microarrays. After induction of renal IRI by clamping the renal pedicles, animals were monitored seven days postoperatively for signs of IRI. In addition to 3-day fasting and two weeks 30%DR, three days of a protein-free diet protected against renal IRI as well, whereas the other diets did not. Gene expression patterns significantly overlapped between all diets except the fat-free diet. Detailed meta-analysis showed involvement of nuclear receptor signaling via transcription factors, including FOXO3, HNF4A and HMGA1. In conclusion, three days of a protein-free diet is sufficient to induce protection against renal IRI similar to 3-day fasting and two weeks of 30%DR. The elucidated network of common protective pathways and transcription factors further improves our mechanistic insight into the increased stress resistance induced by short-term DR.

Liver DNA methylation analysis in adult female C57BL/6JxFVB mice following perinatal exposure to bisphenol A.

Bisphenol A (BPA) is a compound released from plastics and other consumer products used in everyday life. BPA exposure early in fetal development is proposed to contribute to programming of chronic diseases like obesity and diabetes, by affecting DNA methylation levels. Previously, we showed that in utero and lactational exposure of C57BL/6JxFVB hybrid mice via maternal feed using a dose range of 0-3000µg/kg body weight/day resulted in a sex-dependent altered metabolic phenotype in offspring at 23 weeks of age. The most univocal effects were observed in females, with reduced body weights and related metabolic effects associated with perinatal BPA exposure. To identify whether the effects of BPA in females are associated with changes in DNA methylation, this was analyzed in liver, which is important in energy homeostasis. Measurement of global DNA methylation did not show any changes. Genome-wide DNA methylation analysis at specific CpG sites in control and 3000µg/kg body weight/day females with the digital restriction enzyme analysis of methylation (DREAM) assay revealed potential differences, that could, however, not be confirmed by bisulfite pyrosequencing. Overall, we demonstrated that the observed altered metabolic phenotype in female offspring after maternal exposure to BPA was not detectably associated with liver DNA methylation changes. Still, other tissues may be more informative.

Programming of metabolic effects in C57BL/6JxFVB mice by exposure to bisphenol A during gestation and lactation.

The global rise in prevalence of obesity is not fully explained by genetics or life style factors. The developmental origins of health and disease paradigm suggests that environmental factors during early life could play a role. In this perspective, perinatal exposure to bisphenol A (BPA) has been indicated as a programming factor for obesity and related metabolic disorders later in life. Here we study early life programming by BPA using an experimental design that is relevant for human exposure. C57BL/6JxFVB hybrid mice were exposed during gestation and lactation via maternal feed to 8 non-toxic doses (0-3000 µg/kg body weight/day (µg/kg bw/d)) of BPA. After weaning, offspring were followed for 20 weeks without further exposure. Adult male offspring showed dose-dependent increases of body and liver weights, no effects on fat pad weights and a dose-dependent decrease in circulating glucagon. Female offspring showed a dose-dependent decrease in body weight, liver, muscle and fat pad weights, adipocyte size, serum lipids, serum leptin and adiponectin. Physical activity was decreased in exposed males and suggested to be increased in exposed females. Brown adipose tissue showed slightly increased lipid accumulation in males and lipid depletion in females, and ucp1 expression was dose-dependently increased in females. The effects in females were more reliable and robust than in males due to wide confidence intervals and potential confounding by litter size for male data. The lowest derived BMDL (lower bound of the (two-sided) 90%-confidence interval for the benchmark dose) of 233 µg/kg bw/d (for interscapular weight in females) was below the proposed BMDL of 3633 µg/kg bw/d as a basis for tolerable daily intake. Although these results suggest that BPA can program for an altered metabolic phenotype, the sexual dimorphism of effects and diversity of outcomes among studies similar in design as the present study do not mark BPA as a specific obesogen. The consistency within the complex of observed metabolic effects suggests that upstream key element(s) in energy homeostasis are modified. Sex-dependent factors contribute to the final phenotypic outcome.

Reproductive and lifestyle determinants of anti-Müllerian hormone in a large population-based study.

CONTEXT: Anti-müllerian hormone (AMH) is an ovarian reserve marker that is increasingly applied in clinical practice as a prognostic and diagnostic tool. Despite increased use of AMH in clinical practice, large-scale studies addressing the influence of possible determinants on AMH levels are scarce. OBJECTIVE: We aimed to address the role of reproductive and lifestyle determinants of AMH in a large population-based cohort of women. DESIGN: In this cross-sectional study, age-specific AMH percentiles were calculated using general linear modeling with CG-LMS (Cole and Green, Lambda, Mu, and Sigma model, an established method to calculate growth curves for children). SETTING: Women from the general community participating in the Doetinchem Cohort study were assessed. PARTICIPANTS: Two thousand three hundred twenty premenopausal women were included. MAIN OUTCOME MEASURE: The effect of female reproductive and lifestyle factors on shifts in age-specific AMH percentiles was studied. RESULTS: In comparison to women with a regular menstrual cycle, current oral contraceptive (OC) users, women with menstrual cycle irregularity, and pregnant women had significantly lower age-specific AMH percentiles (for OC use, 11 percentiles lower; for cycle irregularity, 11 percentiles lower; and for pregnancy, 17 percentiles lower [P value for all <.0001]). Age at menarche and age at first childbirth were not associated with the age-specific AMH percentile. Higher parity was associated with 2 percentiles higher age-specific AMH (P = .02). Of the lifestyle factors investigated, current smoking was associated with 4 percentiles lower age-specific AMH percentiles (P = .02), irrespective of the smoking dose. Body mass index, waist circumference, alcohol consumption, physical exercise, and socioeconomic status were not significantly associated with age-specific AMH percentiles. CONCLUSIONS: This study demonstrates that several reproductive and lifestyle factors are associated with age-specific AMH levels. The lower AMH levels associated with OC use and smoking seem reversible, as effects were confined to current use of OC or cigarettes. It is important to give careful consideration to the effect of such determinants when interpreting AMH in a clinical setting and basing patient management on AMH.