Physical frailty and sarcopenia are two common and largely overlapping geriatric conditions upstream of the disabling cascade. The lack of a unique operational definition for physical frailty and sarcopenia and the complex underlying pathophysiology make the development of biomarkers for these conditions extremely challenging. Indeed, the current definitional ambiguities of physical frailty and sarcopenia, together with their heterogeneous clinical manifestations, impact the accuracy, specificity, and sensitivity of individual biomarkers proposed so far. In this review, the current state of the art in the development of biomarkers for physical frailty and sarcopenia is presented. A novel approach for biomarker identification and validation is also introduced that moves from the ‘one fits all’ paradigm to a multivariate methodology.
Ageing; Disability; Physical performance; Circulating markers; Imaging; Multivariate modelling
The Lyon brace is commonly prescribed in many European countries to patients with thoracic curves and is based on the three-point pressure system.
The purpose of this study was to evaluate the efficacy of Lyon bracing for the conservative treatment of adolescent females with idiopathic thoracic curves in a case series selected on the basis of the Scoliosis Research Society (SRS) Committee on Bracing and Nonoperative Management Standardization Criteria and followed the guidelines on management of idiopathic scoliosis with corrective braces, proposed by the International Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT).
Prospective study based on an ongoing database.
From 1297 patients treated for idiopathic scoliosis between 1995 and 2014 fulfill the inclusion criteria 102 patients treated with Lyon brace. Of these, 69 patients had a definite outcome, 17 have abandoned treatment e 16 are still in treatment. The 104 patients were adolescent females with curvatures in the thoracic spine and a pre-treatment Risser score ranging from 0 to 2. All patients were prescribed with full-time Lyon bracing. The minimum duration of follow-up was 24 months after the end of weaning (mean: 41.64 ± 31.45 months). Anteroposterior radiographs were used to estimate the curve magnitude (CM) at 5 time points: beginning of treatment (t1), one year after the beginning of treatment (t2), intermediate time between t1 and t4 (t3), end of weaning (t4), 2-year minimum follow-up from t4 (t5). Three outcomes were distinguished: curve correction, curve stabilization and curve progression.
The results from our study showed that of the 69 patients with a definite outcome the CM mean value was 31.51° ± 4.34 SD at t1 and 20° ± 7.6 SD at t5. Curve correction was accomplished in 85.5 % of patients, curve stabilization was obtained in 13 % of patients and curve progression was evident in only 1.5 %. None of the patients were recommended surgery post-bracing. Of 17 patients who abandoned the treatment, at the time of abandonment (14.4 age) have achieved curve correction in 13 cases (77 %), stabilization in 53 cases (18 %) and progression in 1 case (5 %).
The Lyon brace, through its biomechanical action on vertebral modeling, is highly effective in correcting thoracic curves in particularly when the SOSORT guidelines were adopted in addition to the SRS criteria.
Adolescent idiopathic scoliosis; Scoliosis Research Society Criteria (SRS); Lyon brace; SOSORT guidelines; conservative treatment
The epidemic of obesity and overweight is spreading worldwide. Excessive adiposity is associated with a myriad of adverse health outcomes, leading to increased healthcare expenditures and shortened life expectancy. In contrast to overeating, calorie restriction (CR), defined as a reduction in food intake without malnutrition, increases both mean and maximum lifespan in a variety of species by reducing the incidence of several chronic degenerative diseases, including cardiovascular disease. The constellation of health benefits brought about by CR results from biological and physiological changes affecting fundamental processes underlying aging and age-related pathologies. Despite the beneficial properties of CR, it is likely that most people will not engage in such a dietary regimen for the long-term. Supplementation with specific compounds mimicking CR may represent a more feasible means to improve health and prolong life. However, evidence on long-term effectiveness and safety of these compounds is not yet available in humans.
obesity; hormesis; stress; inflammation; apoptosis; sirtuins
In the present study, we investigated the effects of 7 and 14 days of re-loading following 14-day muscle unweighting (hindlimb suspension, HS) on iron transport, non-heme iron levels and oxidative damage in the gastrocnemius muscle of young (6 months) and old (32 months) male Fischer 344×Brown Norway rats. Our results demonstrated that old rats had lower muscle mass, higher levels of total non-heme iron and oxidative damage in skeletal muscle in comparison with young rats. Non-heme iron concentrations and total non-heme iron amounts were 3.4- and 2.3-fold higher in aged rats as compared with their young counterparts, respectively. Seven and 14 days of re-loading was associated with higher muscle weights in young animals as compared with age-matched HS rats, but there was no difference in muscle weights among aged HS, 7 and 14 days of re-loading rats, indicating that aged rats may have a lower adaptability to muscle disuse and a lower capacity to recover from muscle atrophy. Protein levels of cellular iron transporters, such as divalent metal transport-1 (DMT1), transferrin receptor-1 (TfR1), Zip14, and ferroportin (FPN), and their mRNA abundance were determined. TfR1 protein and mRNA levels were significantly lower in aged muscle. Seven and 14 days of re-loading were associated with higher TfR1 mRNA and protein levels in young animals in comparison with their age-matched HS counterparts, but there was no difference between cohorts in aged animals, suggesting adaptive responses in the old to cope with iron deregulation. The extremely low expression of FPN in skeletal muscle might lead to inefficient iron export in the presence of iron overload and play a critical role in age-related iron accumulation in skeletal muscle. Moreover, oxidative stress was much greater in the muscles of the older animals measured as 4-hydroxy-2-nonhenal (HNE)-modified proteins and 8-oxo-7,8-dihydroguanosine levels. These markers remained fairly constant with either HS or re-loading in young rats. In old rats, HNE-modified proteins and 8-oxo-7,8-dihydroguanosine levels were markedly higher in HS and were lower after 7 days of recovery. However, no difference was observed following 14 days of recovery between control and re-loading animals. In conclusion, advanced age is associated with disruption of muscle iron metabolism which is further perturbed by disuse and persists over a longer time period.
Aging; Sarcopenia; Iron metabolism; Hindlimb unloading and re-loading; Skeletal muscle atrophy
Sarcopenia, the loss of skeletal muscle mass and function that occurs with aging, is associated with increased risk for several adverse health outcomes, including frailty, disability, falls, loss of independent living, and mortality. At present, no pharmacological treatment exists that is able to definitely halt the progression of sarcopenia. Likewise, no pharmacological remedies are yet available to prevent the onset of age-related muscle wasting. In this scenario, the combination of nutritional interventions and physical exercise appears to be the most effective strategy presently available for the management of sarcopenia. The purposes of this review are to summarize the current knowledge on the role of nutrition as a countermeasure for sarcopenia, illustrate the mechanisms of action of relevant dietary agents on the aging muscle, and introduce novel nutritional strategies that may help preserve muscle mass and function into old age. Issues related to the identification of the optimal timing of nutritional interventions in the context of primary and secondary prevention are also discussed. Finally, the prospect of elaborating personalized dietary and physical exercise recommendations through the implementation of integrated, high-throughput analytic approaches is illustrated.
aging; protein; vitamin D; creatine; omics; personalized diet; Pachinko model
Sarcopenia, the age-related decline in muscle mass and function, represents a significant health issue due to the high prevalence of frailty and disability associated with this condition. Nevertheless, the cellular mechanisms responsible for the loss of muscle mass in old age are still largely unknown. An altered regulation of myocyte apoptosis has recently emerged as a possible contributor to the pathogenesis of sarcopenia. Studies in animal models have shown that the severity of skeletal muscle apoptosis increases over the course of aging and correlates with the degree of muscle mass and strength decline. Several apoptotic pathways are operative in aged muscles, with the mitochondria- and TNF-α-mediated pathways likely being the most relevant to sarcopenia. However, despite the growing number of studies on the subject, a definite mechanistic link between myocyte apoptosis and age-related muscle atrophy has not yet been established. Furthermore, the evidence on the role played by apoptosis in human sarcopenia is still sparse. Clearly, further research is required to better define the involvement of myocyte apoptosis in the pathogenesis of muscle loss at advanced age. This knowledge will likely help in the design of more effective therapeutic strategies to preserve muscle mass into old age, thus fostering independence of the elderly population and reducing the socioeconomic burden associated with sarcopenia.
aging; sarcopenia; myonuclear apoptosis; mitochondria; tumor necrosis factor-alpha (TNF-α); caspases; endonuclease G (EndoG); apoptosis inducing factor (AIF)
The present study evaluates the effects of a 6-month treatment with an ACE-inhibitor (ie, fosinopril) on serum concentrations of total IGF-1 and IGF binding protein (IGFBP)-3 in older adults at high risk for cardiovascular disease.
Data are from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN) study, a double-blind, crossover, randomized, placebo-controlled trial.
Participants were recruited from the communities of Winston Salem, NC, and Greensboro, NC.
Subjects ≥55 years old with high cardiovascular disease risk profile.
The intervention consisted of 6-month administration of fosinopril vs. placebo.
Serum concentrations of total IGF-1 and IGFBP-3 were measured in 100 participants of the TRAIN study at baseline, 6-month and 12-month follow-up visits. Differences in total IGF-1 and IGFBP-3 concentrations were assessed using two-sided paired t-tests.
The mean age of participants (47% women) was 66.5 (standard deviation 7.2) years. Serum concentrations of total IGF-1 were significantly higher after 6-month treatment with fosinopril compared to placebo (203.73 ng/mL vs 194.24 ng/mL; p=0.02): After ACE-inhibitor intervention, significantly higher serum IGFBP-3 concentrations compared to controls (4308.81 ng/mL vs 4086.93 ng/mL; p=0.03) were also reported.
A six-month treatment with fosinopril increases systemic levels of total IGF-1 and IGFBP-3 in older adults with high cardiovascular risk profile. This may represent a potential biological explanation to the beneficial effects of ACE-inhibition on stroke, ischemic heart disease and insulin resistance.
Angiotensin Converting Enzyme inhibitor; Insulin like growth factor 1; Insulin like growth factor binding protein 3; older adults
skeletal muscle; frailty; autophagy; apoptosis; mitochondrial dysfunction; signaling pathways; satellite cells; treatment
Sarcopenia, the age-related loss of muscle mass and function, imposes a dramatic burden on individuals and society. The development of preventive and therapeutic strategies against sarcopenia is therefore perceived as an urgent need by health professionals and has instigated intensive research on the pathophysiology of this syndrome. The pathogenesis of sarcopenia is multifaceted and encompasses lifestyle habits, systemic factors (e.g., chronic inflammation and hormonal alterations), local environment perturbations (e.g., vascular dysfunction), and intramuscular specific processes. In this scenario, derangements in skeletal myocyte mitochondrial function are recognized as major factors contributing to the age-dependent muscle degeneration. In this review, we summarize prominent findings and controversial issues on the contribution of specific mitochondrial processes – including oxidative stress, quality control mechanisms and apoptotic signaling – on the development of sarcopenia. Extramuscular alterations accompanying the aging process with a potential impact on myocyte mitochondrial function are also discussed. We conclude with presenting methodological and safety considerations for the design of clinical trials targeting mitochondrial dysfunction to treat sarcopenia. Special emphasis is placed on the importance of monitoring the effects of an intervention on muscle mitochondrial function and identifying the optimal target population for the trial.
mitophagy; vascular dysfunction; fusion and fission; apoptosis; biomarkers
Osteoporosis is a highly prevalent condition characterized by decreases in bone mass and microarchitectural alterations. Bone fractures, especially of the hip and vertebrae, are the most burdensome complications of osteoporosis, being associated with high risk of disability, institutionalization and mortality. The detection of osteoporosis relies on the quantification of bone mineral density via imaging techniques such as dual-energy X-ray absorptiometry. However, therapeutic decision-making should be based on a comprehensive fracture risk assessment, which may be obtained through validated algorithms. Once the decision of treating has been taken, non-pharmacological strategies should be implemented together with the prescription of anti-osteoporotic agents. Numerous drugs are currently available to treat osteoporosis and the choice of a specific compound should be guided by efficacy and safety considerations. The present review provides a concise synopsis of the current evidence in the management of osteoporosis, from screening to drug prescription. Novel anti-osteoporotic agents are also briefly presented.
vitamin D; denosumab; bisphosphonates; teriparatide; strontium ranelate
Recently, we showed that administration of the angiotensin-converting enzyme inhibitor enalapril to aged rats attenuated muscle strength decline and mitigated apoptosis in the gastrocnemius muscle. The aim of the present study was to investigate possible mechanisms underlying the muscle-protective effects of enalapril. We also sought to discern the effects of enalapril mediated by nitric oxide (NO) from those independent of this signaling molecule. Eighty-seven male Fischer 344 × Brown Norway rats were randomly assigned to receive enalapril (n = 23), the NO synthase (NOS) inhibitor NG-nitro-l-arginine methyl ester (l-NAME; n = 22), enalapril + l-NAME (n = 19), or placebo (n = 23) from 24 to 27 months of age. Experiments were performed on the tibialis anterior muscle. Total NOS activity and the expression of neuronal, endothelial, and inducible NOS isoforms (nNOS, eNOS, and iNOS) were determined to investigate the effects of enalapril on NO signaling. Transcript levels of tumor necrosis factor-alpha (TNF-α) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) were assessed to explore actions of enalapril on inflammation and mitochondrial biogenesis, respectively. Protein expression of energy-sensing and insulin signaling mediators, including protein kinase B (Akt-1), phosphorylated Akt-1 (pAkt-1), mammalian target of rapamycin (mTOR), AMP-activated protein kinase subunit alpha (AMPKα), phosphorylated AMPKα (pAMPKα), and the glucose transporter GLUT-4, was also determined. Finally, the generation of hydrogen peroxide (H2O2) was quantified in subsarcolemmal (SSM) and intermyofibrillar (IFM) mitochondria. Enalapril increased total NOS activity, which was prevented by l-NAME co-administration. eNOS protein content was enhanced by enalapril, but not by enalapril + l-NAME. Gene expression of iNOS was down-regulated by enalapril either alone or in combination with l-NAME. In contrast, protein levels of nNOS were unaltered by treatments. The mRNA abundance of TNF-α was reduced by enalapril relative to placebo, with no differences among any other group. PCG-1α gene expression was unaffected by enalapril and lowered by enalapril + l-NAME. No differences in protein expression of Akt-1, pAkt-1, AMPKα, pAMPKα, or GLUT-4 were detected among groups. However, mTOR protein levels were increased by enalapril compared with placebo. Finally, all treatment groups displayed reduced SSM, but not IFM H2O2 production relative to placebo. Our data indicate that enalapril induces a number of metabolic adaptations in aged skeletal muscle. These effects result from the concerted modulation of NO and angiotensin II signaling, rather than from a dichotomous action of enalapril on the two pathways. Muscle protection by enalapril administered late in life appears to be primarily mediated by mitigation of oxidative stress and pro-inflammatory signaling.
Aging; Nitric oxide synthase (NOS) isoforms; Mitochondria; mTOR; Glucose tolerance; l-NAME; Inflammation; ACE inhibitors
Over the last years, evidence has accumulated in support of bracing as an effective treatment option in patients with idiopathic scoliosis. Yet, little information is available on the impact of compliance on the outcome of conservative treatment in scoliotic subjects. The aim of the present study was to prospectively evaluate the association between compliance to brace treatment and the progression of scoliotic curve in patients with idiopathic adolescent (AIS) or juvenile scoliosis (JIS).
Among 1.424 patients treated for idiopathic scoliosis, 645 were eligible for inclusion criteria. Three outcomes were distinguished in agreement with the SRS criteria: curve correction, curve stabilization and curve progression. Brace wearing was assessed by one orthopaedic surgeon (LA) and scored on a standardized form. Compliance to treatment was categorized as complete (brace worn as prescribed), incomplete A (brace removed for 1 month), incomplete B (brace removed for 2 months), incomplete C (brace removed during school hours), and incomplete D (brace worn overnight only). Chi square test, T test or ANOVA and ANOVA for repeated measures tests were used as statistical tests.
The results from our study showed that at follow-up the compliance was: Complete 61.1%; Incomplete A 5.2%; Incomplete B 10.7%; Incomplete C 14.2%; Incomplete D 8.8%. Curve correction was accomplished in 301/319 of Complete, 19/27 Incomplete A, 25/56 Incomplete B, 52/74 Incomplete C, 27/46 Incomplete D. Cobb mean value was 29.8 ± 7.5 SD at beginning and 17.1 ± 10.9 SD at follow-up. Both Cobb and Perdriolle degree amelioration was significantly higher in patients with complete compliance over all other groups, both in juvenile, both in adolescent scoliosis. In the intention-to-treat analysis, the rate of surgical treatment was 2.1% among patients with definite outcome and 12.1% among those with drop-out. Treatment compliance showed significant interactions with time.
Curve progression and referral to surgery are lower in patients with high brace compliance. Bracing discontinuation up to 1 month does not impact on the treatment outcome. Conversely, wearing the brace only overnight is associated with a high rate of curve progression.
Compliance; Juvenile idiopathic scoliosis; Adolescent idiopathic scoliosis; PASB brace; Conservative treatment
The Juvenile idiopathic scoliosis by age of onset, severity and evolutivity is source of great doubts concerning the purpose and use of conservative treatment. The different clinical experiences leave unsolved the question that arises in applying a conservative treatment when the patients are effectively forward a long growing period, in scoliosis characterized by inevitable evolutivity. The purpose of the present prospective study was to determine the effectiveness of conservative treatment in Juvenile idiopathic scoliosis.
From 1238 patients treated for idiopathic scoliosis between 1995 and 2012 fulfill the inclusion criteria 163 patients treated with PASB, Lyon brace and Milwaukee. Of these, 113 patients had a definite outcome, 27 have abandoned treatment e 23 are still in treatment. The minimum follow-up was 24 months. Radiographs were used to estimate the curve magnitude (CM) and the torsion of the apical vertebra (TA) at 5 time points: beginning (t1), 6 months after the beginning (t2), intermediate time between t1 and t4 (t3), end of weaning (t4), 2-years minimum follow-up (t5). Three outcomes were distinguished in agreement with SRS criteria: correction, stabilization and progression.
The results from our study showed that of the 113 patients with a definite outcome CM mean value was 29.6 ± 7.5 SD at t1 and 16.9 ± 11.1 SD at t5. TA was 13.5 ± 5.4 SD at t1 and 8.5 ± 5.6 at t5. The variations between CM t5-t1 and TA t5-t1 were statistically significantly different. Curve correction was accomplished in 88 patients (77.8%), stabilization was obtained in 18 patients (15.9%). 7 patients (6.19%) have a progression and 4 of these were recommended for surgery. Of 26 patients who abandoned the treatment, at the time of abandonment (12.5 age) have achieved curve correction in 19 cases (70.0%), stabilization in 5 cases (19%) and progression in 3 cases (11%). Of these patients, reviewed at the end of growing, four have been operated on.
Our study confirmed that conservative treatment with brace is highly effective in treating juvenile idiopathic scoliosis, in particular most patients reaching a complete curve correction and only 4.9% of patients need surgery.
Juvenile idiopathic scoliosis; Scoliosis research society criteria (SRS); PASB brace; Lyon brace; SOSORT guidelines; Conservative treatment
Muscle loss during aging and disuse is a highly prevalent and disabling condition, but knowledge about cellular pathways mediating muscle atrophy is still limited. Given the postmitotic nature of skeletal myocytes, the maintenance of cellular homeostasis relies on the efficiency of cellular quality control mechanisms. In this scenario, alterations in mitochondrial function are considered a major factor underlying sarcopenia and muscle atrophy. Damaged mitochondria are not only less bioenergetically efficient, but also generate increased amounts of reactive oxygen species, interfere with cellular quality control mechanisms, and display a greater propensity to trigger apoptosis. Thus, mitochondria stand at the crossroad of signaling pathways that regulate skeletal myocyte function and viability. Studies on these pathways have sometimes provided unexpected and counterintuitive results, which suggests that they are organized into a complex, heterarchical network that is currently insufficiently understood. Untangling the complexity of such a network will likely provide clinicians with novel and highly effective therapeutics to counter the muscle loss associated with aging and disuse. In this review, we summarize the current knowledge on the mechanisms whereby mitochondrial dysfunction intervenes in the pathogenesis of sarcopenia and disuse atrophy, and highlight the prospect of targeting specific processes to treat these conditions.
apoptosis; autophagy; fission; fusion; mitophagy; oxidative stress
elderly; aging; disability; preventive medicine; physical performance; geriatric assessment; skeletal muscle; definition and concepts
Background: Telomere shortening in peripheral blood mononuclear cells (PBMCs) has been associated with biological age and several chronic degenerative diseases. However, the relationship between telomere length and sarcopenia, a hallmark of the aging process, is unknown. The aim of the present study was therefore to determine whether PBMC telomeres obtained from sarcopenic older persons were shorter relative to non-sarcopenic peers. We further explored if PBMC telomere length was associated with frailty, a major clinical correlate of sarcopenia.
Methods: Analyses were conducted in 142 persons aged ≥65 years referred to a geriatric outpatient clinic (University Hospital). The presence of sarcopenia was established according to the European Working Group on Sarcopenia in Older People criteria, with bioelectrical impedance analysis used for muscle mass estimation. The frailty status was determined by both the Fried’s criteria (physical frailty, PF) and a modified Rockwood’s frailty index (FI). Telomere length was measured in PBMCs by quantitative real-time polymerase chain reaction according to the telomere/single-copy gene ratio (T/S) method.
Results: Among 142 outpatients (mean age 75.0 ± 6.5 years, 59.2% women), sarcopenia was diagnosed in 23 individuals (19.3%). The PF phenotype was detected in 74 participants (52.1%). The average FI score was 0.46 ± 0.17. PBMC telomeres were shorter in sarcopenic subjects (T/S = 0.21; 95% CI: 0.18–0.24) relative to non-sarcopenic individuals (T/S = 0.26; 95% CI: 0.24–0.28; p = 0.01), independent of age, gender, smoking habit, or comorbidity. No significant associations were determined between telomere length and either PF or the FI.
Conclusion: PBMC telomere length, expressed as T/S values, is shorter in older outpatients with sarcopenia. The cross-sectional assessment of PBMC telomere length is not sufficient at capturing the complex, multidimensional syndrome of frailty.
frailty; biological age; muscle aging; oxidative stress; inflammation; bioelectrical impedance analysis
Background: Failure to meet an adequate dietary intake is involved in the pathogenesis of sarcopenia and osteoporosis, which in turn increase the risk for falls and fractures, respectively. Older people with hip fracture are often protein-malnourished at hospitalization. Whether low protein-energy intake is associated with muscle atrophy in hip-fractured patients is presently unknown. This information is necessary for the development of novel strategies to manage this especially vulnerable patient population. The aim of this study was, therefore, to explore the relationship between dietary intake and muscle mass in older hip-fractured patients.
Methods: Analyses were conducted in hip-fractured elderly admitted to an orthopedic and trauma surgery ward (University Hospital). Muscle mass was estimated by bioelectrical impedance analysis within 24 h from admission. Dietary information was collected via 24-h dietary recall and nutrient intake calculated by a nutrition software.
Results: Among 62 hip-fractured patients (mean age 84.6 ± 7.6 years, 84% women), the average energy intake was 929.2 ± 170.3 Kcal day−1, with higher values reported by men (1.046.8 ± 231.4 Kcal day−1) relative to women (906.5 ± 148.3 Kcal day−1; p = 0.01). Absolute and normalized protein intake was 50.0 ± 13.5 g day−1 and 0.88 ± 0.27 g kg (body weight)–1 day–1, respectively, with no gender differences. A positive correlation was determined between total energy intake and muscle mass (r = 0.384; p = 0.003). Similarly, protein and leucine consumption was positively correlated with muscle mass (r = 0.367 and 0.311, respectively; p = 0.005 for both).
Conclusion: A low intake of calories, protein, and leucine is associated with reduced muscle mass in hip-fractured elderly. Given the relevance of sarcopenia as a risk factor for adverse outcomes in this patient population, our findings highlight the importance of a comprehensive dietary assessment for the detection of nutritional deficits predisposing to or aggravating muscle atrophy.
sarcopenia; diet; recommended dietary allowance; leucine; disability; malnutrition; bioelectrical impedance analysis; muscle atrophy
During the aging process, an accumulation of non-heme iron disrupts cellular homeostasis and contributes to the mitochondrial dysfunction typical of various neuromuscular degenerative diseases. Few studies have investigated the effects of iron accumulation on mitochondrial integrity and function in skeletal muscle and liver tissue. Thus, we isolated liver mitochondria (LM), as well as quadriceps-derived subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM), from male Fischer 344× Brown Norway rats at 8, 18, 29 and 37 months of age. Non-heme iron content in SSM, IFM and LM was significantly higher with age, reaching a maximum at 37 months of age. The mitochondrial permeability transition pore (mPTP) was more susceptible to the opening in aged mitochondria containing high levels of iron (i.e. SSM and LM) compared to IFM. Furthermore, mitochondrial RNA oxidation increased significantly with age in SSM and LM, but not in IFM. Levels of mitochondrial RNA oxidation in SSM and LM correlated positively with levels of mitochondrial iron, whereas a significant negative correlation was observed between the maximum Ca2+ amounts needed to induce mPTP opening and iron contents in SSM, IFM and LM. Overall, our data suggest that age-dependent accumulation of mitochondrial iron may increase mitochondrial dysfunction and oxidative damage, thereby enhancing the susceptibility to apoptosis.
mitochondrial aging; mitochondrial iron homeostasis; mitochondrial permeability transition pore; mitochondrial RNA; oxidative stress; skeletal muscle subsarcolemmal and interfibrillar mitochondria
Sarcopenia, the age-related loss of skeletal muscle mass, is a significant public health concern that continues to grow in relevance as the population ages. Certain conditions have the strong potential to coincide with sarcopenia to accelerate the progression of muscle atrophy in older adults. Among these conditions are co-morbid diseases common to older individuals such as cancer, kidney disease, diabetes, and peripheral artery disease. Furthermore, behaviors such as poor nutrition and physical inactivity are well-known to contribute to sarcopenia development. However, we argue that these behaviors are not inherent to the development of sarcopenia but rather accelerate its progression. In the present review, we discuss how these factors affect systemic and cellular mechanisms that contribute to skeletal muscle atrophy. In addition, we describe gaps in the literature concerning the role of these factors in accelerating sarcopenia progression. Elucidating biochemical pathways related to accelerated muscle atrophy may allow for improved discovery of therapeutic treatments related to sarcopenia.
Aging; Proteolysis; Satellite Cells; HIV; COPD; Disability
Age-related loss of muscle mass and strength (sarcopenia) leads to a decline in physical function and frailty in the elderly. Among the many proposed underlying causes of sarcopenia, mitochondrial dysfunction is inherent in a variety of aged tissues. The intent of this study was to examine the effect of aging on key groups of regulatory proteins involved in mitochondrial biogenesis and how this relates to physical performance in two groups of sedentary elderly participants, classified as high- and low-functioning based on the Short Physical Performance Battery test. Muscle mass was decreased by 38% and 30% in low-functioning elderly (LFE) participants when compared to young and high-functioning elderly (HFE) participants, respectively, and positively correlated to physical performance. Mitochondrial respiration in permeabilized muscle fibers was reduced (41%) in the LFE group when compared to the young, and this was associated with a 30% decline in COX activity. Levels of key metabolic regulators, SIRT3 and PGC-1α were significantly reduced (50%) in both groups of elderly participants when compared to young. Similarly, the fusion protein OPA1 was lower in muscle from elderly subjects, however no changes were detected in Mfn2, Drp1 or Fis1 among the groups. In contrast, protein import machinery (PIM) components Tom22 and cHsp70 were increased in the LFE group when compared to the young. This study suggests that aging in skeletal muscle is associated with impaired mitochondrial function and altered biogenesis pathways, and that this may contribute to muscle atrophy and the decline in muscle performance observed in the elderly population.
aging; sarcopenia; mitochondria; skeletal muscle; PGC-1α
Anorexia of aging, defined as a loss of appetite and/or reduced food intake, affects a significant number of elderly people and is far more prevalent among frail individuals. Anorexia recognizes a multifactorial origin characterized by various combinations of medical, environmental and social factors. Given the interconnection between weight loss, sarcopenia and frailty, anorexia is a powerful, independent predictor of poor quality of life, morbidity and mortality in older persons. One of the most important goals in the management of older, frail people is to optimize their nutritional status. To achieve this objective it is important to identify subjects at risk of anorexia and to provide multi-stimulus interventions that ensure an adequate amount of food to limit and/or reverse weight loss and functional decline. Here, we provide a brief overview on the relevance of anorexia in the context of sarcopenia and frailty. Major pathways supposedly involved in the pathogenesis of anorexia are also illustrated. Finally, the importance of treating anorexia to achieve health benefits in frail elders is highlighted.
elderly; sarcopenia; ghrelin; malnutrition; weight loss; disability; energy metabolism
Recent scientific studies have advanced the notion of chronic inflammation as a major risk factor underlying aging and age-related diseases. In this review, low-grade, unresolved, molecular inflammation is described as an underlying mechanism of aging and age-related diseases, which may serve as a bridge between normal aging and age-related pathological processes. Accumulated data strongly suggest that continuous (chronic) up-regulation of pro-inflammatory mediators (e.g., TNF-α, IL-1β, 6, COX-2, iNOS) are induced during the aging process due to an age-related redox imbalance that activates many pro-inflammatory signaling pathways, including the NF-κB signaling pathway. These pro-inflammatory molecular events are discussed in relation to their role as basic mechanisms underlying aging and age-related diseases. Further, the anti-inflammatory actions of aging-retarding caloric restriction and exercise are reviewed. Thus, the purpose of this review is to describe the molecular roles of age-related physiological functional declines and the accompanying chronic diseases associated with aging. This new view on the role of molecular inflammation as a mechanism of aging and age-related pathogenesis can provide insights into potential interventions that may affect the aging process and reduce age-related diseases, thereby promoting healthy longevity.
molecular inflammation; aging; calorie restriction; exercise; cytokines; oxidative stress; inflammatory diseases; age-related diseases; obesity; sarcopenia; dementia; atherosclerosis; cancer; osteoporosis
Study reports clinical and functional outcomes of surgical treatment in a case series of nine patients with distal fibular tumours.
Nine patients with distal fibular tumours were observed between 2005 and 2010. A PubMed search was performed using the terms “fibula”, “lower limb tumour [cancer]”, “sarcoma”, “Ewing”, “peroneal”, “fibular metastasis”, and “limb-salvage surgery”.
In all our patients, lesions were unilateral. All patients complained of pain; limping was present in 5 of 9 tumours. Patients were managed surgically, except one who underwent local radiotherapy. In six patients, a benign or tumor-like lesion was detected. Malignancies consisted of metastatic lung adenocarcinoma (two cases) or multifocal mesenchymal cancer (one case). Non-malignant lesions were treated by curettage and filling, followed by internal fixation when needed. In malignant or locally aggressive lesions, metadiaphyseal fibular resection was performed. The literature search retrieved either case reports or small case series, reflecting the rarity of distal fibular tumours. Surgical treatment was successful in all patients with benign lesions, whereas the rate of success was 40–100 % in case of malignancies.
Given the low incidence of distal fibular tumours, controversies exist about the optimal surgical management. Clinical observation and imaging should be reserved to asymptomatic benign lesions. In non-malignant tumours causing pain, limping, and pathological fractures; in malignancies, surgery is recommended. Finally, in patients with asymptomatic lesions of uncertain nature, biopsy and histological examination should be performed to plan appropriate management.