Aging is a predominant risk factor for numerous chronic diseases that limit healthspan 1. Mechanisms of aging are thus increasingly recognized as potential therapeutic targets. Blood from young mice reverses aspects of aging and disease across multiple tissues 2-10 , which supports a Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:
Attenuated growth hormone and insulin-like growth factor-1 (GH/IGF-1) signaling is associated with extended lifespan in several animal models. However, the effect of diminished GH/IGF-1 activity on survival in humans has not been confirmed. We tested the hypothesis that IGF-1 levels in nonagenarians (n = 184), measured at study enrollment, predict the duration of their incremental survival. In the Kaplan–Meier analysis, females with IGF-1 levels below the median (≤ 96 ng mL−1) had significantly longer survival compared with females with levels above the median, P < 0.01. However, this survival advantage was not observed in males (P = 0.83). On the other hand, in both males and females with a history of cancer, lower IGF-1 levels predicted longer survival (P < 0.01). IGF-1 level remained a significant predictor of survival duration in linear regression models after multivariable adjustment in females (P = 0.01) and individuals with a history of cancer (P < 0.01). We show for the first time that low IGF-1 levels predict life expectancy in exceptionally long-lived individuals.
Interventions that target fundamental aging processes have the potential to transform human health and health care. A variety of candidate drugs have emerged from basic and translational research that may target aging processes. Some of these drugs are already in clinical use for other purposes, such as metformin and rapamycin. However, designing clinical trials to test interventions that target the aging process poses a unique set of challenges. This paper summarizes the outcomes of an international meeting co-ordinated by the NIH-funded Geroscience Network to further the goal of developing a translational pipeline to move candidate compounds through clinical trials and ultimately into use. We review the evidence that some drugs already in clinical use may target fundamental aging processes. We discuss the design principles of clinical trials to test such interventions in humans, including study populations, interventions, and outcomes. As examples, we offer several scenarios for potential clinical trials centered on the concepts of health span (delayed multimorbidity and functional decline) and resilience (response to or recovery from an acute health stress). Finally, we describe how this discussion helped inform the design of the proposed Targeting Aging with Metformin study.
Summary Mutations resulting in reduced signaling of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis are associated with increased life and health-span across model organisms. Similar findings have been noted in human cohorts with functional mutations in the somatotropic axis, suggesting that this pathway may also be relevant to human aging and protection from age-related diseases. While epidemiological data indicates that low circulating IGF-1 level may protect aging populations from cancer, results remain inconclusive regarding most other diseases. We propose that studies in humans and animals need to consider differences in sex, pathway function, organs, and time-specific effects of GH/IGF-1 signaling in order to better define the role of the somatotropic axis in aging. Agents that modulate signaling of the GH/IGF-1 pathway are available for human use, but before they can be implemented in clinical studies that target aging and age-related diseases, researchers need to address the challenges discussed in this review.
Objectives To determine if there is a compression of morbidity in a sample of Ashkenazi Jewish centenarians, similar to what has been reported in other cohorts with exceptional longevity. Design Case control study. Setting Longevity Genes Project (LGP) and New England Centenarian Study (NECS). Participants 439 LGP (mean age: 97.8 ± 2.8) and 1,498 NECS (mean age: 101.4 ± 4.0) participants compared to their respective younger referent cohorts of 696 LGP and 302 NECS controls, respectively. Measurements Self and proxy reports of age of onset of cancer, cardiovascular disease, diabetes mellitus, hypertension, osteoporosis, and stroke. Results Long-lived individuals from both LGP and NECS compared to their respective younger referent groups delay the age of onset of cancer, cardiovascular disease, diabetes mellitus, hypertension, and osteoporosis. The relative risk of overall morbidity is 0.12 in NECS males and 0.20 in NECS females compared to the younger NECS referents and 0.18 in LGP males and 0.24 in LGP females compared to younger male and female LGP referents. The age at which 20% of each of the centenarian groups experienced specific diseases was significantly delayed by between 18 and 24 years relative to the referent groups, when stratified by sex. Conclusion The similar extension of health-span and compression of morbidity seen in both the NECS and LGP centenarian samples further validates the utility of these rare individuals for the study of factors that delay or prevent a broad spectrum of diseases otherwise associated with mortality and disability.
The insulin-like growth factor 1 (IGF1) signaling pathway has emerged as a major regulator of the aging process, from rodents to humans. However, given the pleiotropic actions of IGF1, its role in the aging brain remains complex and controversial. While IGF1 is clearly essential for normal development of the central nervous system, conflicting evidence has emerged from preclinical and human studies regarding its relationship to cognitive function, as well as cerebrovascular and neurodegenerative disorders. This review delves into the current state of the evidence examining the role of IGF1 in the aging brain, encompassing preclinical and clinical studies. A broad examination of the data indicates that IGF1 may indeed play opposing roles in the aging brain, depending on the underlying pathology and context. Some evidence suggests that in the setting of neurodegenerative diseases that manifest with abnormal protein deposition in the brain, such as Alzheimer's disease, reducing IGF1 signaling may serve a protective role by slowing disease progression and augmenting clearance of pathologic proteins to maintain cellular homeostasis. In contrast, inducing IGF1 deficiency has also been implicated in dysregulated function of cognition and the neurovascular system, suggesting that some IGF1 signaling may be necessary for normal brain function. Furthermore, states of acute neuronal injury, which necessitate growth, repair and survival signals to persevere, typically demonstrate salutary effects of IGF1 in that context. Appreciating the dual, at times opposing 'Dr Jekyll' and 'Mr Hyde' characteristics of IGF1 in the aging brain, will bring us closer to understanding its impact and devising more targeted IGF1-related interventions.
Blockade of endogenous opioids with naloxone during antecedent hypoglycemia improves HAAF in patients with T1DM by ameliorating the epinephrine response and restoring EGP.
Aims/hypothesisSkin fluorescence (SF) is a non-invasive marker of AGEs and is associated with the long-term complications of diabetes. SF increases with age and is also greater among individuals with diabetes. A familial correlation of SF suggests that genetics may play a role. We therefore performed parallel genome-wide association studies of SF in two cohorts.MethodsCohort 1 included 1,082 participants, 35–67 years of age with type 1 diabetes. Cohort 2 included 8,721 participants without diabetes, aged 18–90 years.Resultsrs1495741 was significantly associated with SF in Cohort 1 (p < 6 × 10−10), which is known to tag the NAT2 acetylator phenotype. The fast acetylator genotype was associated with lower SF, explaining up to 15% of the variance. In Cohort 2, the top signal associated with SF (p = 8.3 × 10−42) was rs4921914, also in NAT2, 440 bases upstream of rs1495741 (linkage disequilibrium r2 = 1.0 for rs4921914 with rs1495741). We replicated these results in two additional cohorts, one with and one without type 1 diabetes. Finally, to understand which compounds are contributing to the NAT2–SF signal, we examined 11 compounds assayed from skin biopsies (n = 198): the fast acetylator genotype was associated with lower levels of the AGEs hydroimidazolones of glyoxal (p = 0.017).Conclusions/interpretationWe identified a robust association between NAT2 and SF in people with and without diabetes. Our findings provide proof of principle that genetic variation contributes to interindividual SF and that NAT2 acetylation status plays a major role.Electronic supplementary materialThe online version of this article (doi:10.1007/s00125-014-3286-9) contains peer-reviewed but unedited supplementary material, which is available to authorised users.
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