Leisure-Time Physical Activity and Cancer Risk Among Older Adults: A Cohort Study

Reduced S-nitrosylation of TGFβ1 elevates its binding affinity towards the receptor and promotes fibrogenic signaling in the breast

Transforming Growth Factor β (TGFβ) is a pleiotropic cytokine closely linked to tumors. TGFβ is often elevated in precancerous breast lesions in association with epithelial-to-mesenchymal transition (EMT), indicating its contribution to precancerous progression. We previously reported that basal nitric oxide (NO) levels declined along with breast cancer progression. We then pharmacologically inhibited NO production in healthy mammary glands of wild-type mice and found that this induced precancerous progression accompanied by desmoplasia and upregulation of TGFβ activity. In the present study, we tested our hypothesis that NO directly S-nitrosylates (forms an NO-adduct at a cysteine residue) TGFβ to inhibit the activity, whereas the reduction of NO denitrosylates TGFβ and de-represses the activity. We introduced mutations to three C-terminal cysteines of TGFβ1 which were predicted to be S-nitrosylated. We found that these mutations indeed impaired S-nitrosylation of TGFβ1 and shifted the binding affinity towards the receptor from the latent complex. Furthermore, in silico structural analyses predicted that these S-nitrosylation-defective mutations strengthen the dimerization of mature protein, whereas S-nitrosylation-mimetic mutations weaken the dimerization. Such differences in dimerization dynamics of TGFβ1 by denitrosylation/S-nitrosylation likely account for the shift of the binding affinities towards the receptor vs. latent complex. Our findings, for the first time, unravel a novel mode of TGFβ regulation based on S-nitrosylation or denitrosylation of the protein.

Influence of negative stereotype on physical activity level among older adults during a training session

The present research examined the effect of a negative stereotype induction on older adults' physical activity level, measured objectively and subjectively. Twenty older adults (18 women and two men; Mage = 67.4, SDage = 4.4) were assigned to a control condition, a neutral condition and a negative stereotype condition during three separate visits (i.e., within-subject design). In each physical activity session, participants performed the same training. Objective physical activity level was the time spent at moderate to vigorous intensity measured by accelerometry and subjective physical activity level was measured with the RPE-session method. Inactivity time was also objectively assessed. Results revealed no effect of the different conditions on objective physical activity level, but subjective physical activity level and inactivity time were lower in the neutral condition and in the negative stereotype condition compared to the control condition. It was suggested that when a negative stereotype is induced, participants perceived the task as less intense compared to the control condition, which result in less inactivity time, suggesting that the negative stereotype had a positive influence on physical activity. Another interesting result was that effects were similar in the negative stereotype condition and in the neutral condition, revealing that the neutral condition might not be a control condition. While these results are not in line with the stereotype threat literature, they echo previous recent studies also showing a positive effect of a negative stereotype induction, calling into question the stereotype threat theory.

An Exercise-Induced Metabolic Shield in Distant Organs Blocks Cancer Progression and Metastatic Dissemination

Exercise prevents cancer incidence and recurrence, yet the underlying mechanism behind this relationship remains mostly unknown. Here we report that exercise induces the metabolic reprogramming of internal organs that increases nutrient demand and protects against metastatic colonization by limiting nutrient availability to the tumor, generating an exercise-induced metabolic shield. Proteomic and ex vivo metabolic capacity analyses of murine internal organs revealed that exercise induces catabolic processes, glucose uptake, mitochondrial activity, and GLUT expression. Proteomic analysis of routinely active human subject plasma demonstrated increased carbohydrate utilization following exercise. Epidemiologic data from a 20-year prospective study of a large human cohort of initially cancer-free participants revealed that exercise prior to cancer initiation had a modest impact on cancer incidence in low metastatic stages but significantly reduced the likelihood of highly metastatic cancer. In three models of melanoma in mice, exercise prior to cancer injection significantly protected against metastases in distant organs. The protective effects of exercise were dependent on mTOR activity, and inhibition of the mTOR pathway with rapamycin treatment ex vivo reversed the exercise-induced metabolic shield. Under limited glucose conditions, active stroma consumed significantly more glucose at the expense of the tumor. Collectively, these data suggest a clash between the metabolic plasticity of cancer and exercise-induced metabolic reprogramming of the stroma, raising an opportunity to block metastasis by challenging the metabolic needs of the tumor.

SIGNIFICANCE

Exercise protects against cancer progression and metastasis by inducing a high nutrient demand in internal organs, indicating that reducing nutrient availability to tumor cells represents a potential strategy to prevent metastasis. See related commentary by Zerhouni and Piskounova, p. 4124.

Association of socioeconomic status measures with physical activity and subsequent frailty in older adults

Background

Despite increased recognition, frailty remains a significant public health challenge.

Objective

we aimed to assess the role of education and income, as well as neighborhood socioeconomic status, on physical activity and subsequent frailty in older adults.

Methods

Using a population-based cohort of older adults, this study examined the relationship between socioeconomic status (SES) factors, physical activity and frailty. The study included 1,799 participants (mean [SD], 74.6 (6.2), 53.3% female) from the "National Health and Nutrition Survey of Older Adults Aged 65 and Over in Israel", conducted in 2005–2006. A follow-up interview was performed 12–14 years later in a subgroup of 601 subjects (mean [SD], age 84[4]; 56% women). Self-reported leisure-time physical activity (LTPA) was measured at both baseline and follow-up. SES measures were assessed at baseline. Frailty was measured at follow-up, using the Fried's Phenotype Model.

Results

All SES measures were strongly and positively associated with LTPA (all p < 0.001). Eighty-two participants (14%) were classified as frail at follow-up. After age and sex adjustment and accounting for attrition bias using inverse probability weighting, baseline LTPA (OR = 2.77, 95% CI: 1.57–4.90, for inactivity; OR = 1.41, 95% CI: 0.75–2.68, for insufficient activity, compared with sufficient activity, P_trend < 0.001) was inversely associated with incident frailty. The association persisted after further adjustment for SES and comorbidity.

Conclusion

Among older individuals, multiple SES measures were positively associated with LTPA, which was a strong predictor of lower subsequent frailty risk.

Optimism and survival: health behaviors as a mediator-a ten-year follow-up study of Chinese elderly people

Background

Optimism—the generalized expectation that good things will happen—is a promising health asset. Mounting evidence indicates that there are specific associations between optimism and survival rates. However, for public health purposes, it is critical to consider whether the relationship between optimism and survival holds for older adults as a whole and to explore the role of health behaviors as potential mediators.

Methods

Prospective data were obtained from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Optimism was measured in 2008, and survival was measured by survival time of the interviewees during the whole observation period from 2008 to 2018. Cox proportional hazard models were employed to evaluate the association between optimism and survival among the elderly. The mediating effect analysis method was used to explore the potential mediating role of health behaviors on the association between optimism and survival.

Results

Compared to less optimistic older adults, optimistic individuals were associated with lower odds of mortality (HR = 0.94, 95% CI = 0.89 − 0.99). Health behaviors are key elements that play a positive role in survival (HR = 0.95, 95% CI = 0.94 − 0.96). Health behaviors played an intermediary role in the relationship between optimism and mortality, and the mediating effect was -0.005.

Conclusions

Optimism and health behaviors were broadly and robustly associated with a lower risk of mortality. Health behaviors mediate the relationship between optimism and mortality. Appropriate intervention should be carried out on optimism and health behaviors among elderly people to improve the likelihood of health in aging.

Physical Activity and Long-Term Mortality Risk in Older Adults with and without Cardiovascular Disease: A Nationwide Cohort Study

AIMS

To evaluate the association between physical activity (PA) levels and mortality among older adults, to determine whether it differs according to cardiovascular disease (CVD) status, and to assess the optimal weekly duration of PA associated with subsequent survival.

METHODS

Participants (n = 1,799) were drawn from a national survey conducted from 2005 to 2006, constituting Israeli adults aged ≥65 years. Sociodemographic, clinical, behavioral, and psychosocial data were collected via interview at study entry. Based on a detailed PA questionnaire and according to published guidelines, participants were classified as sufficiently active, insufficiently active, and inactive. CVD status was self-reported. Mortality data (last follow-up, December 2016) were obtained from the Israeli Ministry of Health. Using Cox models, inverse probability weighted hazard ratios (HRs) for mortality, based on propensity score, were estimated for PA categories.

RESULTS

Among the participants at baseline (mean age, 74.6 years), 559 (31.1%) were sufficiently active, 506 (28.1%) were insufficiently active, and 734 (40.8%) were inactive. During follow-up (mean, 9.0 years), 684 participants (38.0%) died. PA was inversely associated with mortality, with propensity score-adjusted HRs (95% confidence intervals) of 0.84 (0.71-1.01) in insufficiently and 0.73 (0.61-0.88) in sufficiently active participants (ptrend < 0.001). No PA-by-CVD interaction was detected on multiplicative scale (p = 0.36) or additive scale (p = 0.58). A monotonic survival benefit was observed until ∼150 min of PA per week, beyond which no further gain was apparent.

CONCLUSIONS

In a nationwide cohort of older adults, nearly 70% did not meet the guideline for PA. PA engagement was inversely associated with long-term mortality risk, similarly in individuals with and without CVD. A maximum survival advantage was achieved at around 150 min of exercise per week.

Protein and physical activity in older persons

PURPOSE OF REVIEW

The aim of this study was to highlight recent evidence on protein requirement and physical activity recommendations in older adults and their interrelationship.

RECENT FINDINGS

Higher protein intake in older adults is beneficial for better physical function, reduced fracture risk, healthy ageing and lower mortality. However, the association between protein quality and health remains inconsistent. Higher physical activity is associated with a lower risk of physical dependence, frailty, cognitive impairment and mortality. Prospectively increasing or even sustaining physical activity can be protective against adverse health outcomes compared with decreasing physical activity. There is a synergistic protective effect of protein intake and physical activity on health. Data on the bidirectional link between protein intake and physical activity are scarce. Whether increasing physical activity can help to increase energy intake (and thus protein intake) and vice versa require further research.

SUMMARY

The key role of protein intake and physical activity in optimizing health in older adults is well established. The synergistic effects of these two modifiable lifestyle factors strengthen the need to consider dietary and physical activity recommendations together. Future research may examine the bidirectional link between diet and physical activity, which could potentially be one of the strategies to increase the uptake of recommendations for protein intake and physical activity in older adults.