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Summary We tested the hypothesis that supplementation of nicotinamide mononucleotide (NMN), a key NAD+ intermediate, increases arterial SIRT1 activity and reverses age-associated arterial dysfunction and oxidative stress. Old control mice (OC) had impaired carotid artery endothelium-dependent dilation (EDD) (60 ± 5% vs. 84 ± 2%), a measure of endothelial function, and nitric oxide (NO)-mediated EDD (37 ± 4% vs. 66 ± 6%), compared with young mice (YC). This age-associated impairment in EDD was restored in OC by the superoxide (O 2 -) scavenger TEMPOL (82 ± 7%). OC also had increased aortic pulse wave velocity (aPWV, 464 ± 31 cm s-1 vs. 337 ± 3 cm s-1) and elastic modulus (EM, 6407 ± 876 kPa vs. 3119 ± 471 kPa), measures of large elastic artery stiffness, compared with YC. OC had greater aortic O 2 - production (2.0 ± 0.1 vs. 1.0 ± 0.1 AU), nitrotyrosine abundance (a marker of oxidative stress), and collagen-I, and reduced elastin and vascular SIRT1 activity, measured by the acetylation status of the p65 subunit of NF[kappa]B, compared with YC. Supplementation with NMN in old mice restored EDD (86 ± 2%) and NO-mediated EDD (61 ± 5%), reduced aPWV (359 ± 14 cm s-1) and EM (3694 ± 315 kPa), normalized O 2 - production (0.9 ± 0.1 AU), decreased nitrotyrosine, reversed collagen-I, increased elastin, and restored vascular SIRT1 activity. Acute NMN incubation in isolated aortas increased NAD+ threefold and manganese superoxide dismutase (MnSOD) by 50%. NMN supplementation may represent a novel therapy to restore SIRT1 activity and reverse age-related arterial dysfunction by decreasing oxidative stress.

Despite advances in syncope evaluation strategies and risk stratification, the high cost of syncope is largely driven by extensive and often repetitive testing. This analysis of a large deidentified US claims database compared the use of diagnostic tests, therapeutic procedures, and the recurrence rate of acute syncope events before and after placement of an insertable cardiac monitor (ICM) in syncope patients. The patients had a minimum of 1 year of continuous enrollment before and 2 years after ICM placement. Among 2140 patients identified, a statistically significant reduction in the use of 14 out of 18 tests was observed during follow-up compared with pre-ICM testing. During the 2-year follow-up, 28.3% of patients underwent cardiac therapeutic interventions after a median of 127 days. Significantly fewer patients experienced acute syncope events during the 1st and 2nd years of ICM follow-up compared with the 1-year pre-ICM period, and the frequency of events per patient also decreased. In conclusion, reductions in diagnostic testing and acute syncope events were observed after ICM placement in a large real-world cohort of unexplained syncope patients. Further studies are needed to prospectively assess the impact of ICM vs. short-term monitoring on patient outcomes and healthcare utilization.

Aging is associated with vascular endothelial dysfunction, reduced exercise tolerance, and impaired whole‐body glucose metabolism. Interleukin‐37 (IL‐37), an anti‐inflammatory cytokine of the interleukin‐1 family, exerts salutary physiological effects in young mice independent of its inflammation‐suppressing properties. Here, we assess the efficacy of IL‐37 treatment for improving physiological function in older age. Old mice (26–28 months) received daily intraperitoneal injections of recombinant human IL‐37 (recIL‐37; 1 µg/200 ml PBS) or vehicle (200 ml PBS) for 10–14 days. Vascular endothelial function (ex vivo carotid artery dilation to increasing doses of acetylcholine, ACh) was enhanced in recIL‐37 vs. vehicle‐treated mice via increased nitric oxide (NO) bioavailability (all p < .05); this effect was accompanied by enhanced ACh‐stimulated NO production and reduced levels of reactive oxygen species in endothelial cells cultured with plasma from IL‐37‐treated animals (p < .05 vs. vehicle plasma). RecIL‐37 treatment increased endurance exercise capacity by 2.4‐fold, which was accompanied by a 2.9‐fold increase in the phosphorylated AMP‐activated kinase (AMPK) to AMPK ratio (i.e., AMPK activation) in quadriceps muscle. RecIL‐37 treatment also improved whole‐body insulin sensitivity and glucose tolerance (p < .05 vs. vehicle). Improvements in physiological function occurred without significant changes in plasma, aortic, and skeletal muscle pro‐inflammatory proteins (under resting conditions), whereas pro‐/anti‐inflammatory IL‐6 was greater in recIL‐37‐treated animals. Plasma metabolomics analysis revealed that recIL‐37 treatment altered metabolites related to pathways involved in NO synthesis (e.g., increased L‐arginine and citrulline/arginine ratio) and fatty acid metabolism (e.g., increased pantothenol and free fatty acids). Our findings provide experimental support for IL‐37 therapy as a novel strategy to improve diverse physiological functions in old age. Physiological function declines with aging, increasing risk of chronic diseases and disability. We show for the first time that treatment with a novel anti‐inflammatory compound interleukin‐37 (IL‐37) improves multiple physiological functions in old mice, and identify potential roles of reduced superoxide production, improved oxidative metabolism and circulating factors in mediating improvements. Our findings support IL‐37 therapy as a novel strategy for improving diverse physiological functions in old age.

Chronological age is an important predictor of morbidity and mortality; however, it is unable to account for heterogeneity in the decline of physiological function and health with advancing age. Several attempts have been made to instead define a “biological age” using multiple physiological parameters in order to account for variation in the trajectory of human aging; however, these methods require technical expertise and are likely too time-intensive and costly to be implemented into clinical practice. Accordingly, we sought to develop a metabolomic signature of biological aging that could predict changes in physiological function with the convenience of a blood sample. A weighted model of biological age was generated based on multiple clinical and physiological measures in a cohort of healthy adults and was then applied to a group of healthy older adults who were tracked longitudinally over a 5–10-year timeframe. Plasma metabolomic signatures were identified that were associated with biological age, including some that could predict whether individuals would age at a faster or slower rate. Metabolites most associated with the rate of biological aging included amino acid, fatty acid, acylcarnitine, sphingolipid, and nucleotide metabolites. These results not only have clinical implications by providing a simple blood-based assay of biological aging, but also provide insight into the molecular mechanisms underlying human healthspan.

Aortic stiffening, assessed as pulse-wave velocity (PWV), increases with age and is an important antecedent to, and independent predictor of, cardiovascular diseases (CVD) and other clinical disorders of aging. Aerobic exercise promotes lower levels of aortic stiffness in older adults, but the underlying mechanisms are incompletely understood, largely due to inherent challenges of mechanistic studies of large elastic arteries in humans. Voluntary wheel running (VWR) is distinct among experimental animal exercise paradigms in that it allows investigation of the physiologic effects of aerobic training without potential confounding influences of aversive molecular signaling related to forced exercise. In this study, we investigated whether VWR in mice may be a suitable model for mechanistic studies (i.e., “reverse translation”) of the beneficial effects of exercise on arterial stiffness in humans. We found that 10 weeks of VWR in old mice (~ 28 months) reversed age-related elevations in aortic PWV assessed in vivo (Old VWR: 369 ± 19 vs. old sedentary: 439 ± 20 cm/s, P < 0.05). The de-stiffening effects of VWR were accompanied by normalization of age-related increases in ex vivo mechanical stiffness of aortic segments and aortic accumulation of collagen-I and advanced glycation end products, as well as lower levels of aortic superoxide and nitrotyrosine. Our results suggest that late-life VWR in mice recapitulates the aortic de-stiffening effects of exercise in humans and indicates important mechanistic roles for decreased oxidative stress and extracellular matrix remodeling. Therefore, VWR is a suitable model for further study of the mechanisms underlying beneficial effects of exercise on arterial stiffness.

In the summer of 2002, the Office of Naval Research asked the Committee on Human Factors to hold a workshop on dynamic social network and analysis. The primary purpose of the workshop was to bring together scientists who represent a diversity of views and approaches to share their insights, commentary, and critiques on the developing body of social network analysis research and application. The secondary purpose was to provide sound models and applications for current problems of national importance, with a particular focus on national security. This workshop is one of several activities undertaken by the National Research Council that bears on the contributions of various scientific disciplines to understanding and defending against terrorism. The presentations were grouped in four sessions - Social Network Theory Perspectives, Dynamic Social Networks, Metrics and Models, and Networked Worlds - each of which concluded with a discussant-led roundtable discussion among the presenters and workshop attendees on the themes and issues raised in the session.

COMMENCING with Lake Santa Fe, in the north, we find it, and Nunan Lake, to the southwest of it, both surrounded by a flat sandy country destitute of \"sinks\" and of rock exposures of any kind. Some distance off, however, to the westward of the former and about four miles west of Waldo, is a small exposure known as the Preston Marl, near old Fort Harlee; and seven or eight miles still farther northwestward in Bradford County, is another large sink.