Current and future pharmacologic treatment of sarcopenia

Health outcomes of sarcopenia: a consensus report by the outcome working group of the Global Leadership Initiative in Sarcopenia (GLIS)

The Global Leadership Initiative in Sarcopenia (GLIS) aims to standardize the definition and diagnostic criteria for sarcopenia into one unifying, common classification. Among other actions to achieve this objective, the GLIS has organized three different working groups (WGs), with the WG on outcomes of sarcopenia focusing on reporting its health outcomes to be measured in clinical practice once a diagnosis has been established. This includes sarcopenia definitions that better predict health outcomes, the preferred tools for measuring these outcomes, and the cutoffs defining normal and abnormal values. The present article synthesizes discussions and conclusions from this WG, composed of 13 key opinion leaders from different continents worldwide. Results rely on systematic reviews, meta-analyses, and relevant cohort studies in the field. With a high level of evidence, sarcopenia is significantly associated with a reduced quality of life, a higher risk of falls and fractures and a higher risk of mortality. Sarcopenia has been moderately associated with a higher risk of reduced instrumental activities of daily living (IADL). However, the GLIS WG found only inconclusive level of evidence to support associations between sarcopenia and higher risks of hospitalization, nursing home admission, mobility impairments, and reduced basic activities of daily living (ADL). This limitation underscores the scarcity of longitudinal studies, highlighting a barrier to understanding its progression and implications over time.

Combined Exercise Training and Nutritional Interventions or Pharmacological Treatments to Improve Exercise Capacity and Body Composition in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease that is associated with significant morbidity, mortality, and healthcare costs. The burden of respiratory symptoms and airflow limitation can translate to reduced physical activity, in turn contributing to poor exercise capacity, muscle dysfunction, and body composition abnormalities. These extrapulmonary features of the disease are targeted during pulmonary rehabilitation, which provides patients with tailored therapies to improve the physical and emotional status. Patients with COPD can be divided into metabolic phenotypes, including cachectic, sarcopenic, normal weight, obese, and sarcopenic with hidden obesity. To date, there have been many studies performed investigating the individual effects of exercise training programs as well as nutritional and pharmacological treatments to improve exercise capacity and body composition in patients with COPD. However, little research is available investigating the combined effect of exercise training with nutritional or pharmacological treatments on these outcomes. Therefore, this review focuses on exploring the potential additional beneficial effects of combinations of exercise training and nutritional or pharmacological treatments to target exercise capacity and body composition in patients with COPD with different metabolic phenotypes.

Role of nutrition in patients with coexisting chronic obstructive pulmonary disease and sarcopenia

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic diseases in the elderly population and is characterized by persistent respiratory symptoms and airflow obstruction. During COPD progression, a variety of pulmonary and extrapulmonary complications develop, with sarcopenia being one of the most common extrapulmonary complications. Factors that contribute to the pathogenesis of coexisting COPD and sarcopenia include systemic inflammation, hypoxia, hypercapnia, oxidative stress, protein metabolic imbalance, and myocyte mitochondrial dysfunction. These factors, individually or in concert, affect muscle function, resulting in decreased muscle mass and strength. The occurrence of sarcopenia severely affects the quality of life of patients with COPD, resulting in increased readmission rates, longer hospital admission, and higher mortality. In recent years, studies have found that oral supplementation with protein, micronutrients, fat, or a combination of nutritional supplements can improve the muscle strength and physical performance of these patients; some studies have also elucidated the possible underlying mechanisms. This review aimed to elucidate the role of nutrition among patients with coexisting COPD and sarcopenia.

Nobiletin Improves D-Galactose-Induced Aging Mice Skeletal Muscle Atrophy by Regulating Protein Homeostasis

Sarcopenia, a decrease in skeletal muscle mass and function caused by aging, impairs mobility, raises the risk of fractures, diabetes, and other illnesses, and severely affects a senior's quality of life. Nobiletin (Nob), polymethoxyl flavonoid, has various biological effects, such as anti-diabetic, anti-atherogenic, anti-inflammatory, anti-oxidative, and anti-tumor properties. In this investigation, we hypothesized that Nob potentially regulates protein homeostasis to prevent and treat sarcopenia. To investigate whether Nob could block skeletal muscle atrophy and elucidate its underlying molecular mechanism, we used the D-galactose-induced (D-gal-induced) C57BL/6J mice for 10 weeks to establish a skeletal muscle atrophy model. The findings demonstrated that Nob increased body weight, hindlimb muscle mass, lean mass and improved the function of skeletal muscle in D-gal-induced aging mice. Nob improved myofiber sizes and increased skeletal muscle main proteins composition in D-gal-induced aging mice. Notably, Nob activated mTOR/Akt signaling to increase protein synthesis and inhibited FOXO3a-MAFbx/MuRF1 pathway and inflammatory cytokines, thereby reducing protein degradation in D-gal-induced aging mice. In conclusion, Nob attenuated D-gal-induced skeletal muscle atrophy. It is a promising candidate for preventing and treating age-associated atrophy of skeletal muscles.

Frailty, sarcopenia and diabetic kidney disease: where do we stand?

The aim of this narrative non-systematic review was to investigate the potential interplay among frailty syndrome, sarcopenia and diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM) patients. Data derived from a limited number of studies underline that DKD is a significant risk factor for frailty. On the other hand, frailty syndrome poses a higher risk for end-stage renal disease (ESRD) in subjects with DKD. In addition, frailty seems to affect the cognitive function and social life of DKD individuals, whilst as DKD deteriorates, there is a higher prevalence of sarcopenia which is a fundamental frailty factor. As a result, it is shown that a bidirectional relation is established between these entities, as diabetes mellitus (DM) affects the components of frailty and sarcopenia and vice versa. This vicious cycle is created through multiple pathophysiologic mechanisms, including the anabolic role of insulin, low-grade inflammation, cytokines and endothelial function, prompting further investigation in this area. Specific nutritional and exercise interventions are imperative to be established in order to ameliorate potential adverse outcomes, concerning these entities.

Effects of losartan and exercise on muscle mass and exercise endurance of old mice

This study evaluated the effects of angiotensin II type I receptor blocker (ARB) on muscle mass and exercise capacity in healthy older animals. The effects of combined ARB and exercise training were also determined. Eighty 18-month-old mice were randomized into the control group (C), exercise group (E), losartan group (L) and losartan plus exercise group (LE). Mice in the L and LE groups received losartan from drinking water every day. Mice in the E and LE groups trained on a treadmill 30 min per day, 3 days per week for 4 months. Exercise endurance and spontaneous physical activity of mice were measured at baseline and monthly for 4 months. After 4 months of intervention, serum interleukin-6 (IL-6) levels, muscle mass, and muscle fiber cross sectional area (CSA) were measured. Total antioxidant capacity (TAC), lipid peroxidation and IL-6 levels were determined in quadriceps. We found that exercise endurance only increased in the E and LE groups. Muscle TAC levels of E, L, and LE groups were greater than that in the C group. Serum IL-6 and lipid peroxidation levels were not different among groups. LE group, but not E and L groups, had greater muscle mass, larger muscle fiber CSA, and greater muscle IL-6 levels than that in the C group after 4 months of intervention. These results suggest that losartan promotes the adaptions of muscle mass with exercise training in healthy older animals.

Sarcopenia versus cancer cachexia: the muscle wasting continuum in healthy and diseased aging

Muscle wasting is one of the major health problems in older adults and is traditionally associated to sarcopenia. Nonetheless, muscle loss may also occur in older adults in the presence of cancer, and in this case, it is associated to cancer cachexia. The clinical management of these conditions is a challenge due to, at least in part, the difficulties in their differential diagnosis. Thus, efforts have been made to better comprehend the pathogenesis of sarcopenia and cancer cachexia, envisioning the improvement of their clinical discrimination and treatment. To add insights on this topic, this review discusses the current knowledge on key molecular players underlying sarcopenia and cancer cachexia in a comparative perspective. Data retrieved from this analysis highlight that while sarcopenia is characterized by the atrophy of fast-twitch muscle fibers, in cancer cachexia an increase in the proportion of fast-twitch fibers appears to happen. The molecular drivers for these specificmuscle remodeling patterns are still unknown; however, among the predominant contributors to sarcopenia is the age-induced neuromuscular denervation, and in cancer cachexia, the muscle disuse experienced by cancer patients seems to play an important role. Moreover, inflammation appears to be more severe in cancer cachexia. Impairment of nutrition-related mediators may also contribute to sarcopenia and cancer cachexia, being distinctly modulated in each condition.

The biphasic and age-dependent impact of klotho on hallmarks of aging and skeletal muscle function

Aging is accompanied by disrupted information flow, resulting from accumulation of molecular mistakes. These mistakes ultimately give rise to debilitating disorders including skeletal muscle wasting, or sarcopenia. To derive a global metric of growing 'disorderliness' of aging muscle, we employed a statistical physics approach to estimate the state parameter, entropy, as a function of genes associated with hallmarks of aging. Escalating network entropy reached an inflection point at old age, while structural and functional alterations progressed into oldest-old age. To probe the potential for restoration of molecular 'order' and reversal of the sarcopenic phenotype, we systemically overexpressed the longevity protein, Klotho, via AAV. Klotho overexpression modulated genes representing all hallmarks of aging in old and oldest-old mice, but pathway enrichment revealed directions of changes were, for many genes, age-dependent. Functional improvements were also age-dependent. Klotho improved strength in old mice, but failed to induce benefits beyond the entropic tipping point.

Uncovering the Bone-Muscle Interaction and Its Implications for the Health and Function of Older Adults (the Wellderly Project): Protocol for a Randomized Controlled Crossover Trial

BACKGROUND

Bone and muscle are closely linked anatomically, biochemically, and metabolically. Acute exercise affects both bone and muscle, implying a crosstalk between the two systems. However, how these two systems communicate is still largely unknown. We will explore the role of undercarboxylated osteocalcin (ucOC) in this crosstalk. ucOC is involved in glucose metabolism and has a potential role in muscle maintenance and metabolism.

OBJECTIVE

The proposed trial will determine if circulating ucOC levels in older adults at baseline and following acute exercise are associated with parameters of muscle function and if the ucOC response to exercise varies between older adults with low muscle quality and those with normal or high muscle quality.

METHODS

A total of 54 men and women aged 60 years or older with no history of diabetes and warfarin and vitamin K use will be recruited. Screening tests will be performed, including those for functional, anthropometric, and clinical presentation. On the basis of muscle quality, a combined equation of lean mass (leg appendicular skeletal muscle mass in kg) and strength (leg press; one-repetition maximum), participants will be stratified into a high or low muscle function group and randomized into the controlled crossover acute intervention. Three visits will be performed approximately 7 days apart, and acute aerobic exercise, acute resistance exercise, and a control session (rest) will be completed in any order. Our primary outcome for this study is the effect of acute exercise on ucOC in older adults with low muscle function and those with high muscle function.

RESULTS

The trial is active and ongoing. Recruitment began in February 2018, and 38 participants have completed the study as of May 26, 2019.

CONCLUSIONS

This study will provide novel insights into bone and muscle crosstalk in older adults, potentially identifying new clinical biomarkers and mechanistic targets for drug treatments for sarcopenia and other related musculoskeletal conditions.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry ACTRN12618001756213; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375925.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18777.

Effect of Antihypertensive and Statin Medication Use on Muscle Performance in Community-Dwelling Older Adults Performing Strength Training

OBJECTIVES

Antihypertensive drugs (AHTD) and statins have been shown to have effects beyond their primarily designed purpose; here we investigate their possible effect on muscle performance and strength in older adults following a physical exercise programme.

DESIGN

The Senior PRoject INtensive Training (SPRINT) study is a randomised, controlled clinical trial designed to evaluate the effects of physical exercise on the immune system and muscle performance in older adults.

PARTICIPANTS

In this secondary analysis, we included 179 independent participants (aged 65 years and above). We applied further categorisation based on medication use: AHTD (including, angiotensin-converting enzyme inhibitors [ACEI], angiotensin II receptor blockers [ARB], β-blockers, and other AHTD) and statins.

INTERVENTION

Participants were allocated randomly to one of the three exercise protocols: intensive strength training 3 times/week (3 × 10 repetitions at 80% of one-repetition maximum), strength endurance training (2 × 30 repetitions at 40% of one-repetition maximum), or control (passive stretching exercise) for 6 weeks.

MEASUREMENTS

The change in maximal hand grip strength (GS), muscle fatigue resistance (FR), Muscle Strength Index (MSI), the 6-min walk test (6MWT), and Timed Up and Go Test (TUG) were assessed before and after 6 weeks of training.

RESULTS

After 6 weeks, muscle strength (MSI and TUG) improved significantly in all training groups compared to baseline, independently of AHTD use. Moreover, AHTD had no effect on exercise improvements, with no significant differences between medication groups, except for TUG in ARB users, which exhibited a significantly lower performance. On the other hand, statin users presented a significantly longer FR time, indicating better performance compared to non-users. Finally, medication did not affect the participants' commitment to the training programme.

CONCLUSION

Our study showed that statins and ARB usage might affect participant's response to strength training. Nevertheless, 6 weeks of training significantly improved muscle strength and performance irrespective of AHTD or statin use.

Towards Personalized Management of Sarcopenia in COPD

The awareness of the presence and consequences of sarcopenia has significantly increased over the past decade. Sarcopenia is defined as gradual loss of muscle mass and strength and ultimately loss of physical performance associated with aging and chronic disease. The prevalence of sarcopenia is higher in chronic obstructive pulmonary disease (COPD) compared to age-matched controls. Current literature suggests that next to physical inactivity, COPD-specific alterations in physiological processes contribute to accelerated development of sarcopenia. Sarcopenia in COPD can be assessed according to current guidelines, but during physical performance testing, ventilatory limitation should be considered. Treatment of muscle impairment can halt or even reverse sarcopenia, despite respiratory impairment. Exercise training and protein supplementation are currently at the basis of sarcopenia treatment. Furthermore, effective current and new interventions targeting the pulmonary system (eg, smoking cessation, bronchodilators and lung volume reduction surgery) may also facilitate muscle maintenance. Better understanding of disease-specific pathophysiological mechanisms involved in the accelerated development of sarcopenia in COPD will provide new leads to refine nutritional, exercise and physical activity interventions and develop pharmacological co-interventions.

A Five-Ingredient Nutritional Supplement and Home-Based Resistance Exercise Improve Lean Mass and Strength in Free-Living Elderly

Old age is associated with lower physical activity levels, suboptimal protein intake, and desensitization to anabolic stimuli, predisposing for age-related muscle loss (sarcopenia). Although resistance exercise (RE) and protein supplementation partially protect against sarcopenia under controlled conditions, the efficacy of home-based, unsupervised RE (HBRE) and multi-ingredient supplementation (MIS) is largely unknown. In this randomized, placebo-controlled and double-blind trial, we examined the effects of HBRE/MIS on muscle mass, strength, and function in free-living, older men. Thirty-two sedentary men underwent twelve weeks of home-based resistance band training (3 d/week), in combination with daily intake of a novel five-nutrient supplement (‘Muscle5’; M5, n = 16, 77.4 ± 2.8 y) containing whey, micellar casein, creatine, vitamin D, and omega-3 fatty acids, or an isocaloric/isonitrogenous placebo (PLA; n = 16, 74.4 ± 1.3 y), containing collagen and sunflower oil. Appendicular and total lean mass (ASM; +3%, TLM; +2%), lean mass to fat ratios (ASM/% body fat; +6%, TLM/% body fat; +5%), maximal strength (grip; +8%, leg press; +17%), and function (5-Times Sit-to-Stand time; −9%) were significantly improved in the M5 group following HBRE/MIS therapy (pre vs. post tests; p < 0.05). Fast-twitch muscle fiber cross-sectional areas of the quadriceps muscle were also significantly increased in the M5 group post intervention (Type IIa; +30.9%, Type IIx, +28.5%, p < 0.05). Sub-group analysis indicated even greater gains in total lean mass in sarcopenic individuals following HBRE/MIS therapy (TLM; +1.65 kg/+3.4%, p < 0.05). We conclude that the Muscle5 supplement is a safe, well-tolerated, and effective complement to low-intensity, home-based resistance exercise and improves lean mass, strength, and overall muscle quality in old age.

Effect of Supplements on Endurance Exercise in the Older Population: Systematic Review

BACKGROUND

Ageing is associated with changes of physical and physiological parameters, but there is evidence that regular physical activity could minimize these effects. Additionally, the older population presents a great risk of suboptimal nutrition. Therefore, the purpose of this study was to review the evidence of nutritional strategies and endurance exercises in the older population.

METHODS

A systematic review was performed based on the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement. The search was carried out in three different databases: PubMed, Web of Science, and SPORTDiscus.

RESULTS

Eight studies were included in the present review. The use of caffeine and beta-alanine supplementation with proteins have been found to be beneficial in both sexes. In older women, a balanced diet, an increase in protein, supplementation with beta hydroxy methyl butyrate, and supplementation with sodium bicarbonate have been favorable. However, no benefit has been seen in older men with sodium bicarbonate or ubiquinone supplementation. Nevertheless, the use of supplements should be prescribed according to individual characteristics and physical activity.

CONCLUSIONS

Caffeine and high protein supplement with beta-alanine may provide positive effects in the older population. In addition, in older women, bicarbonate supplementation and beta-hydroxyethyl butyrate (HMB), lysine, and arginine supplementation have shown positive effects on exercise performance.

Improving Dietary Protein Quality Reduces the Negative Effects of Physical Inactivity on Body Composition and Muscle Function

BACKGROUND

Brief periods of physical inactivity can compromise muscle health. Increasing dietary protein intake is potentially beneficial but complicated by difficulties reconciling anabolic potential with a realistic food volume and energy intake. We sought to determine whether increasing dietary protein quality could reduce the negative effects of physical inactivity.

METHODS

Twenty healthy, older men and women completed 7 days of bed rest followed by 5 days of rehabilitation. Volunteers consumed a mixed macronutrient diet (MIXED: N = 10; 68 ± 2 years; 1,722 ± 29 kcal/day; 0.97 ± 0.01 g protein/kg/day) or an isoenergetic, whey-augmented, higher protein quality diet (WHEY: N = 10; 69 ± 1 years; 1,706 ± 23 kcal/day; 0.90 ± 0.01 g protein/kg/day). Outcomes included body composition, blood glucose, insulin, and a battery of physical function tests.

RESULTS

During bed rest, both groups experienced a 20% reduction in knee extension peak torque (p < .05). The WHEY diet partially protected leg lean mass (-1,035 vs. -680 ± 138 g, MIXED vs. WHEY; p = .08) and contributed to a greater loss of body fat (-90 vs. -233 ± 152 g, MIXED vs. WHEY; p < .05). Following rehabilitation, knee extension peak torque in the WHEY group fully recovered (-10.0 vs. 2.2 ± 4.1 Nm, MIXED vs. WHEY; p = .05). Blood glucose, insulin, aerobic capacity, and Short Physical Performance Battery (SPPB) changes were similar in both dietary conditions (p > .05).

CONCLUSIONS

Improving protein quality without increasing total energy intake has the potential to partially counter some of the negative effects of bed rest in older adults.

Nutritional status and COVID-19: an opportunity for lasting change?

The coronavirus disease of 2019 (COVID-19) pandemic has placed many healthcare systems, including the NHS, under unprecedented pressure. Mortality appears to be highest among older people and those with comorbidities, who are also often the most at risk of undernutrition in society. Despite international efforts to identify a specific treatment, therapy remains supportive and is principally focused on optimising respiratory function. However, the timely identification and correction of undernutrition also has the potential to improve outcomes cost-effectively, and should not be forgotten. This piece outlines why nutritional status may be particularly compromised during this crisis, among both the population and hospital inpatients. Practical steps to improve nutritional status at a time when hospital services are particularly stretched are also considered. Finally, the case is made for behaviour change at all levels including government, the general population and healthcare professionals.

Cachexia and Sarcopenia in Older Adults with Cancer: A Comprehensive Review

Cancer cachexia is a syndrome characterized by weight loss with accompanying loss of muscle and/or fat mass and leads to impaired patient function and physical performance and is associated with a poor prognosis. It is prevalent in older adults with cancer; age-associated physiologic muscle wasting and weakness, also known as sarcopenia, can compound deficits associated with cancer cachexia in older adults and makes studying this condition more complex in this population. Multiple measurement options are available to assess the older patient with cancer and cachexia and/or sarcopenia including anthropometric measures, imaging modalities such as Dual X-ray absorptiometry (DEXA) and Computed Tomography (CT), muscular strength and physical performance testing, and patient-reported outcomes (PROs). A geriatric assessment (GA) is a useful tool when studying the older patient with cachexia given its comprehensive ability to capture aging-sensitive PROs. Interventions focused on nutrition and increasing physical activity may improve outcomes in older adults with cachexia. Efforts to develop targeted pharmacologic therapies with cachexia have not been successful thus far. Formal treatment guidelines, an updated consensus definition for cancer cachexia and the development of a widely adapted assessment tool, much like the GA utilized in geriatric oncology, could help advance the field of cancer cachexia over the next decade.

Malnutrition associated with an increased risk of postoperative complications following hepatectomy in patients with hepatocellular carcinoma

BACKGROUND

The aim of this study was to analyze the nutritional risk factors for postoperative complications following hepatic resection for hepatocellular carcinoma (HCC).

METHODS

The preoperative nutritional status of patients with HCC who underwent hepatic resection was evaluated using the scored Patient-Generated Subjective Global Assessment (PG-SGA). The perioperative variables were compared between well-nourished and malnourished patients. Regression analysis was employed to identify the risk factors for postoperative complications.

RESULTS

The overall operative mortality and morbidity of 287 patients who underwent resection for HCC were 1.7% and 44.3%, respectively. Upon admission, 96 (33.4%) study participants were malnourished, which was associated with a significantly higher PG-SGA score (P < 0.001), higher frequency of comorbidity (P < 0.001), more postoperative complications (P < 0.001) and a longer length of hospital stay (P < 0.001). In addition, major complications (Clavien-Dindo classification ≥ IIIa) occurred significantly more frequently in the malnourished group (P < 0.01). Age ≥70 years (risk ratio [RR] = 2.50, P = 0.008) and PG-SGA score ≥ 4 ([RR] = 9.85, P < 0.001) were significant risk factors for postoperative complications.

CONCLUSIONS

The PG-SGA score is an effective tool for predicting postoperative complications in patients with HCC following hepatic resection.

The Effect of Myopenia on the Inflammatory Response Early after Colorectal Surgery

BACKGROUND

Myopenia (low skeletal muscle mass) is associated with an increased risk of complications following colorectal surgery, however, the underlying mechanism is poorly understood. This study investigates the effect of myopenia on the early postoperative systemic inflammatory response.

MATERIALS AND METHODS

In 78 patients undergoing colorectal surgery, the presence of myopenia was preoperatively assessed using computed tomography images of the third lumbar vertebra. Interleukin-8 (IL-8) and soluble tumor necrosis factor receptor-1 (TNFRSF1A) were measured in plasma before and 4 h after start of surgery as part of a randomized controlled trial investigating the effect of perioperative gum chewing on the inflammatory response. Multivariable linear regression analysis was performed to assess the effect of myopenia on inflammatory markers while correcting for possible confounders.

RESULTS

Four hours after start of surgery, IL-8 was higher in patients with myopenia than in patients without myopenia (352 ± 268 vs. 239 ± 211 pg/ml, P = 0.048), while TNFRSF1A was similar between groups. After adjusting for sex and the intervention with perioperative gum chewing, myopenia remained associated with higher postoperative IL-8 concentrations (P = 0.047).

CONCLUSION

Myopenia may affect IL-8 early after colorectal surgery. However, more studies are needed to validate these findings.

Frailty in elderly diabetes patients

Frailty is a state of vulnerability and a consequence of cumulative decline in multiple physiological systems over a lifespan. The occurrence of frailty depends on deterioration in muscle and nerve function, declining cardiopulmonary reserve and loss of executive function. Diabetes mellitus (DM) often causes functional impairment in each of the above systems, thus leading to a loss of whole body homeostasis and deterioration in physical function. Inability of self-management in DM patients may also have considerable impact on the development of sarcopenia/frailty. Thus, there may be positive feedback between the progression of diabetic complications and frailty/sarcopenia. While various factors are involved in this process, insulin resistance or insulin depletion may be an important factor in the progression of frailty in diabetes patients since insulin is well known to be an anabolic hormone in muscle. Interestingly, in our study targeting elderly DM patients, low HbA1c was a significant and independent risk factor for frailty, as assessed using a broad sense frailty scale, the Clinical Frailty Scale (CSF), suggesting that reverse metabolism due to malnutrition in elderly type 2 DM patients might be involved. Therefore, an intervention that includes proper nutrition and exercise training may be essential for the prevention of frailty. The pathogenesis of frailty in DM patients is extensively discussed in this review.

Injected Human Muscle Precursor Cells Overexpressing PGC-1α Enhance Functional Muscle Regeneration after Trauma

While many groups demonstrated new muscle tissue formation after muscle precursor cell (MPC) injection, the capacity of these cells to heal muscle damage, for example, sphincter in stress urinary incontinence, in long-term is still limited. Therefore, the first goal of our project was to optimize the functional regenerative potential of hMPC by genetic modification to overexpress human peroxisome proliferator-activated receptor gamma coactivator 1-alpha (hPGC-1α), key regulator of exercise-mediated adaptation. Moreover, we aimed at establishing a feasible methodology for noninvasive PET visualization of implanted cells and their microenvironment in muscle crush injury model. PGC-1α-bioengineered muscles showed enhanced marker expression for myogenesis (α-actinin, MyHC, and Desmin), vascularization (VEGF), neuronal (ACHE), and mitochondrial (COXIV) activity. Consistently, use of hPGC-1α_hMPCs produced significantly increased contractile force one to three weeks postinjury. PET imaging showed distinct differences in radiotracer signals ([¹⁸F]Fallypride and [¹¹C]Raclopride (both targeting dopamine 2 receptors (D2R)) and [⁶⁴Cu]NODAGA-RGD (targeting neovascularization)) between GFP_hMPCs and hD2R_hPGC-1α_hMPCs. After muscle harvesting, inflammation levels were in parallel to radiotracer uptake amount, with significantly lower uptake in hPGC-1α overexpressing samples. In summary, we facilitated early functional muscle tissue regeneration, introducing a novel approach to improve skeletal muscle regeneration. Besides successful tracking of hMPCs in muscle crush injuries, we showed that in high-inflammation areas, the specificity of radioligands might be significantly reduced, addressing a possible bottleneck of neovascularization PET imaging.

Polypharmacy as a Risk Factor for Clinically Relevant Sarcopenia: Results From the Berlin Aging Study II

Background

Sarcopenia affects more than 10% of older adults. Next to age-associated physiologic changes, diseases like diabetes or inflammatory, neurological, malignant and endocrine disorders may contribute to the development of sarcopenia. Likewise, polypharmacy, i.e., multiple drug use, is common among older adults. Although the two conditions frequently co-occur, the association of polypharmacy with sarcopenia has not yet been examined. We investigated the association of polypharmacy and sarcopenia in a large cohort of community-dwelling older adults (60-84 years).

Methods

Thousand five hundred and two participants from the Berlin Aging Study II were included. Polypharmacy was defined as concurrent use of 5 or more drugs (prescription and nonprescription). Body composition was assessed with dual-energy X-ray absorptiometry, and appendicular lean mass (ALM) was calculated as sum of the four limbs' lean mass. Sarcopenia was defined as low ALM-to-body mass index (BMI)-ratio using validated sex-specific cutoffs.

Results

Mean age was 68.7 ± 3.7 years, 50.7% were female. The median (interquartile range) number of drugs was 2 (1-4); 21.1% of subjects reported regular use of ≥5 drugs. Subjects with polypharmacy were more often sarcopenic according to the applied ALM/BMI-cutoffs (16.3% vs 6.9%, p < 0.001), with a higher BMI (p < 0.001) and lower ALM/BMI (p < 0.001), but no significant difference in mean ALM. Notably, polypharmacy was also associated with higher rates of reduced gait speed and exhaustion. Even after multivariable adjustment (sex, age, comorbid conditions and physical activity) polypharmacy was consistently associated with a significantly increased likelihood of sarcopenia (odds ratio = 2.24, 95% confidence interval [CI] = 1.33-3.75).

Conclusion

Polypharmacy is associated with clinically relevant sarcopenia, as assessed by a low ALM/BMI.

Sarcopenia

Sarcopenia refers to age-related muscle loss, defined using a combination of appendicular muscle mass, muscle strength, and physical performance measures. The pathogenesis depends on a balance between positive and negative regulators of muscle growth. Sarcopenia increases the risk for falls, fractures, dependency, use of hospital services, institutionalization, poor quality of life, and mortality. In clinical practice, brief screening tools, such as the 5-item SARC-F score, may be useful. Although pharmacologic treatments are actively being studied, the current mainstay consists of optimizing nutrition status, in particular protein and vitamin D status, and resistance exercises.

Ampelopsin attenuates the atrophy of skeletal muscle from d-gal-induced aging rats through activating AMPK/SIRT1/PGC-1α signaling cascade

The atrophy of skeletal muscle is highly correlated with oxidative damage, excessive apoptosis and dysfunctional autophagy. Ampelopsin, a natural flavonoid, has multiple biological functions including anti-inflammatory, anti-oxidative, and hepatoprotective functions. Sprague-Dawley (SD) rats subjected to intraperitoneal injection of d-galactose (d-gal) at the dose of 150mg/kg·d revealed an obvious atrophy of skeletal muscle with significantly reduced muscle mass/body mass ratio, cross-sectional area and fiber diameter of skeletal muscle in d-gal-induced aging rats when compared to normal control rats without d-gal administration for 6 consecutive weeks. In contrast, the combinatorial administration of d-gal at the identical dose and DHM at the dose of 100 or 200mg/kg·d could alleviate the reduction of these hallmarks associated with the atrophy of skeletal muscle. In addition, d-gal administration could result in obvious apoptosis and impaired autophagy in skeletal muscle, which could be mitigated upon DHM treatment due to its role in decreasing ubiquitin and Atrogin-1/MAFbx and up-regulating AMPK and SIRT1 signal pathways. Therefore, DHM may be a potential candidate for the prevention and treatment of skeletal muscle atrophy associated aging process.

Human Muscle Precursor Cells Overexpressing PGC-1α Enhance Early Skeletal Muscle Tissue Formation

Muscle precursor cells (MPCs) are activated satellite cells capable of muscle fiber reconstruction. Therefore, autologous MPC transplantation is envisioned for the treatment of muscle diseases. However, the density of MPCs, as well as their proliferation and differentiation potential, gradually declines with age. The goals of this research were to genetically modify human MPCs (hMPCs) to overexpress the peroxisome proliferator-activated receptor γ coactivator (PGC-1α), a key regulator of exercise-mediated adaptation, and thereby to enhance early skeletal muscle formation and quality. We were able to confirm the sustained myogenic phenotype of the genetically modified hMPCs. While maintaining their viability and proliferation potential, PGC-1α-modified hMPCs showed an enhanced myofiber formation capacity in vitro. Engineered muscle tissues were harvested 1, 2, and 4 weeks after subcutaneous injection of cell-collagen suspensions, and histological analysis confirmed the earlier myotube formation in PGC-1α-modified samples, predominantly of slow-twitch myofibers. Increased contractile protein levels were detected by Western blot. In summary, by genetically modifying hMPCs to overexpress PGC-1α, we were able to promote early muscle fiber formation in vitro and in vivo, with an initial switch to slow-type myofibers. Therefore, overexpressing PGC-1α is a novel strategy to further enhance skeletal muscle tissue engineering.

Nutritional Assessment in Primary Care

Alterations in nutritional status are common and can be associated with increased morbidity and mortality. However, for healthcare providers, the definition of malnutrition is vague, insensitive, and poorly standardized. In contrast, nutrition risk is more easily defined, and recognizes that both poor nutritional status and disease severity contribute to increased morbidity and mortality. Clinicians need to identify patients who may already have evidence of nutrient deficiencies or have disease processes that affect nutrition risk. This article reviews risk assessment tools and provides practical tips to screen patients and identify those whose nutrition risk warrants specialized nutrition therapy.

Oxandrolone Augmentation of Resistance Training in Older Women: A Randomized Trial

INTRODUCTION

Sarcopenia is disproportionately present in older women with disability, and optimum treatment is not clear. We conducted a double-blind, randomized, placebo-controlled trial to determine whether oxandrolone administration in elderly women improves body composition or physical function beyond that which occurs in response to progressive resistance training (PRT).

METHODS

Twenty-nine sedentary women (age 74.9 ± 6.8 yr; 5.9 ± 2.8 medications per day) were randomized to receive high-intensity PRT (three times a week for 12 wk) combined with either oxandrolone (10 mg·d(-1)) or an identical placebo. Peak strength was assessed for leg press, chest press, triceps, knee extension, and knee flexion. Power was assessed for leg press and chest press. Physical function measures included static and dynamic balance, chair rise, stair climb, gait speed, and 6-min walk test. Body composition was assessed using dual energy x-ray absorptiometry.

RESULTS

Oxandrolone treatment augmented increases in lean tissue for the whole body (2.6 kg; 95% confidence interval (CI), 1.0-4.2 kg; P = 0.003), arms (0.3 kg; 95% CI, 0.1-0.5 kg; P = 0.001), legs (0.8 kg; 95% CI, 0.1-1.4 kg; P = 0.018), and trunk (1.4 kg; 95% CI, 0.4-2.3 kg; P = 0.004). Oxandrolone also augmented loss of fat tissue of the whole body (-1 kg; 95% CI, -1.6 to -0.4; P = 0.002), arms (-0.2 kg; 95% CI, -0.5 to -0.02 kg; P = 0.032), legs (-0.4 kg; 95% CI, -0.6 to -0.1; P = 0.009), and tended to reduce trunk fat (-0.4 kg; 95% CI, -0.9 to 0.04; P = 0.07). Improvements in muscle strength and power, chair stand, and dynamic balance were all significant over time (P < 0.05) but not different between groups (P > 0.05).

CONCLUSIONS

Oxandrolone improves body composition adaptations to PRT in older women over 12 wk without augmenting muscle function or functional performance beyond that of PRT alone.

Sarcopenia, Frailty, and Diabetes in Older Adults

Populations are aging and the prevalence of diabetes mellitus is increasing tremendously. The number of older people with diabetes is increasing unexpectedly. Aging and diabetes are both risk factors for functional disability. Thus, increasing numbers of frail or disabled older patients with diabetes will increase both direct and indirect health-related costs. Diabetes has been reported as an important risk factor of developing physical disability in older adults. Older people with diabetes have lower muscle mass and weaker muscle strength. In addition, muscle quality is poorer in diabetic patients. Sarcopenia and frailty have a common soil and may share a similar pathway for multiple pathologic processes in older people. Sarcopenia is thought to be an intermediate step in the development of frailty in patients with diabetes. Thus, early detection of sarcopenia and frailty in older adults with diabetes should be routine clinical practice to prevent frailty or to intervene earlier in frail patients.

SARC-F: a symptom score to predict persons with sarcopenia at risk for poor functional outcomes

BACKGROUND

A brief, inexpensive screening test for sarcopenia would be helpful for clinicians and their patients. To screen for persons with sarcopenia, we developed a simple five-item questionnaire (SARC-F) based on cardinal features or consequences of sarcopenia.

METHODS

We investigated the utility of SARC-F in the African American Health (AAH) study, Baltimore Longitudinal Study of Aging (BLSA), and National Health and Nutrition Examination Survey (NHANES). Internal consistency reliability for SARC-F was determined using Cronbach's alpha. We evaluated SARC-F factorial validity using principal components analysis and criterion validity by examining its association with exam-based indicators of sarcopenia. Construct validity was examined using cross-sectional and longitudinal differences among those with high (≥4) vs. low (<4) SARC-F scores for mortality and health outcomes.

RESULTS

SARC-F exhibited good internal consistency reliability and factorial, criterion, and construct validity. AAH participants with SARC-F scores ≥ 4 had more Instrumental Activity of Daily Living (IADL) deficits, slower chair stand times, lower grip strength, lower short physical performance battery scores, and a higher likelihood of recent hospitalization and of having a gait speed of <0.8 m/s. SARC-F scores ≥ 4 in AAH also were associated with 6 year IADL deficits, slower chair stand times, lower short physical performance battery scores, having a gait speed of <0.8 m/s, being hospitalized recently, and mortality. SARC-F scores ≥ 4 in the BLSA cohort were associated with having more IADL deficits and lower grip strength (both hands) in cross-sectional comparisons and with IADL deficits, lower grip strength (both hands), and mortality at follow-up. NHANES participants with SARC-F scores ≥ 4 had slower 20 ft walk times, had lower peak force knee extensor strength, and were more likely to have been hospitalized recently in cross-sectional analyses.

CONCLUSIONS

The SARC-F proved internally consistent and valid for detecting persons at risk for adverse outcomes from sarcopenia in AAH, BLSA, and NHANES.

Case finding for sarcopenia in geriatric inpatients: performance of bioimpedance analysis in comparison to dual X-ray absorptiometry

Background

Sarcopenia is a common geriatric syndrome associated with serious adverse health outcomes. The European Working Group on Sarcopenia in Older People (EWGSOP) suggests different methods for case finding for sarcopenia. However, data comparing the different methodological options are scarce for geriatric inpatients.

Methods

On the basis of the recommendations of the EWGSOP sixty geriatric inpatients underwent measurement of gait speed, hand grip strength and muscle mass by both, dual X-ray absorptiometry (DXA) and bioimpedance analysis (BIA). By linear regression analysis and Bland-Altman plots muscle mass measurements of DXA and BIA were compared. Outcomes of the DXA- and BIA-based approaches for classifying participants as having normal or reduced muscle mass and sarcopenia according to the EWGSOP case finding algorithm were compared by raw agreement and kappa statistics. Finally, on the hypothetical assumption that the DXA-based approach can be set as reference, the performance of the BIA-based approach is illustrated.

Results

Muscle mass measured by BIA was highly correlated to DXA (r > 0.9), but BIA systematically overestimated muscle mass. The mean difference between DXA and BIA was −1.30 kg (p < 0.001) for appendicular and −2.33 kg (p < 0.001) for total muscle mass. The raw agreement between the DXA- and BIA-based approaches for classifying participants as having normal or reduced muscle mass was at best 80 % depending on the BIA cut-offs used. Functional prescreening according to the sarcopenia case finding algorithm of the EWGSOP reduced the need for muscle mass measurement by 37 %, but only marginally changed the agreement between the DXA- and BIA-based approaches.

Conclusion

Clinicians should be aware that in geriatric inpatients the BIA-based approaches resulted in highly different subgroups of sarcopenic/non-sarcopenic subjects compared to the DXA-based approach following the EWGSOP case finding algorithm. In this pilot-study the BIA-based approach misclassified nearly 1 out of 6 patients if the DXA-based approach is taken as reference.

Acquired Muscle Weakness in the Surgical Intensive Care Unit

Muscle weakness is common in the surgical intensive care unit (ICU). Low muscle mass at ICU admission is a significant predictor of adverse outcomes. The consequences of ICU-acquired muscle weakness depend on the underlying mechanism. Temporary drug-induced weakness when properly managed may not affect outcome. Severe perioperative acquired weakness that is associated with adverse outcomes (prolonged mechanical ventilation, increases in ICU length of stay, and mortality) occurs with persistent (time frame: days) activation of protein degradation pathways, decreases in the drive to the skeletal muscle, and impaired muscular homeostasis. ICU-acquired muscle weakness can be prevented by early treatment of the underlying disease, goal-directed therapy, restrictive use of immobilizing medications, optimal nutrition, activating ventilatory modes, early rehabilitation, and preventive drug therapy. In this article, the authors review the nosology, epidemiology, diagnosis, and prevention of ICU-acquired weakness in surgical ICU patients.

BMPs and the muscle-bone connection

Muscle and bone are two intimately connected tissues. A coordinated interplay between these tissues at mechanical levels is required for their development, function and ageing. Evidence is emerging that several genes and molecular pathways exert a pleiotropic effect on both muscle and bone. Bone morphogenetic proteins (BMPs) are secreted signal factors belonging to the transforming growth factor β (TGFβ) superfamily. BMPs have an essential role during bone and cartilage formation and maintenance. Recently, we and others have demonstrated that the BMP pathway also has a role in controlling adult skeletal muscle mass. Thus, BMPs become crucial regulators of both bone and muscle formation and homeostasis. In this review we will discuss the signalling downstream BMP and its role in muscle-bone interaction. This article is part of a Special Issue entitled "Muscle Bone Interactions".

A four-season molecule: osteocalcin. Updates in its physiological roles

Osteocalcin (OC) is the main non-collagenous hydroxyapatite-binding protein synthesized by osteoblasts, odontoblasts, and hypertrophic chondrocytes. It has a regulatory role in mineralization and it is considered a marker of bone cell metabolism. Recent findings evidenced new extra-skeletal roles for OC, depicting it as a real hormone. OC shares many functional features with the common hormones, such as tissue-specific expression, circadian rhythm, and synthesis as a pre-pro-molecule. However, it has some peculiar features making it a unique molecule: OC exists in different forms based on the degree of carboxylation. Indeed, OC has three glutamic acid residues, in position 17, 21, and 24, which are subject to γ-carboxylation, through the action of a vitamin K-dependent γ-glutamyl carboxytransferase. The degree of carboxylation, and thus the negative charge density, determines the affinity for the calcium ions deposited in the extracellular matrix of the bone. The modulation of the carboxylation could, thus, represent the mechanism by which the body controls the circulating levels, and hence the hormonal function, of OC. There are evidences linking OC, and the bone metabolism, with a series of endocrine (glucose metabolism, energy metabolism, fertility) physiological (muscle activity) and pathological functions (ectopic calcification). Aim of this review is to give a full overview of the physiological roles of OC by collecting the newest experimental findings on this intriguing molecule.

Reproducibility of jumping mechanography and traditional measures of physical and muscle function in older adults

SUMMARY

Improved approaches to assess functional change over time are needed to optimally reduce fall/fracture risk; jumping mechanography (JM) may be one such methodology. In this study, JM parameters were more reproducible than traditional functional tests. JM may be better able to demonstrate efficacy of interventions to mitigate sarcopenia.

INTRODUCTION

Jumping mechanography (JM), a tool using maximal countermovement jumps performed on a force plate, may more reliably assess muscle function than traditional methods. The purpose of this study was to examine JM retest reliability in older adults compared with commonly used muscle and physical function assessments.

METHODS

Community-dwelling individuals age≥70 years performed physical and muscle function assessments including the short physical performance battery (SPPB), grip strength, and JM on multiple occasions over 3 months. JM parameters included body weight-corrected peak power and jump height. Appendicular lean mass was measured by dual energy x-ray (DXA). Mixed effects linear regression models were used to estimate between- and within-person variability summarized as intra-class correlation coefficients (ICC).

RESULTS

Ninety-seven individuals (49 females, 48 males, mean age 80.7 years) participated. All testing was well tolerated; no participant sustained injury. Jump power, height, and grip strength were greater (p<0.0001) in men than women. Grip strength, jump power, and height had excellent ICCs (0.95, 0.93, and 0.88, respectively); chair rise, SPPB score, and gait speed had lower ICCs (0.81, 0.77, and 0.76, respectively).

CONCLUSION

In older adults, JM has excellent retest reliability, is stable over time, and can be performed safely. JM retest reliability was comparable to grip strength and possibly better than SPPB and gait speed. JM is a promising tool for muscle function assessment in older adults. Comparison of this approach with traditional assessment tools in longitudinal interventional studies is needed.

Sarcopenia: the new definitions

PURPOSE OF REVIEW

To highlight the new international definitions of sarcopenia.

RECENT FINDINGS

New international definitions of sarcopenia have been evaluated and shown to be predictive of poor outcomes in older persons.

SUMMARY

There is now international agreement that the definition for sarcopenia should include not only muscle mass, but also some measure of muscle function, such as walking speed or distance or grip strength.

Prevalence, incidence, and clinical impact of sarcopenia: facts, numbers, and epidemiology-update 2014

Sarcopenia is now defined as a decline in walking speed or grip strength associated with low muscle mass. Sarcopenia leads to loss of mobility and function, falls, and mortality. Sarcopenia is a major cause of frailty, but either condition can occur without the other being present. Sarcopenia is present in about 5 to 10 % of persons over 65 years of age. It has multiple causes including disease, decreased caloric intake, poor blood flow to muscle, mitochondrial dysfunction, a decline in anabolic hormones, and an increase in proinflammatory cytokines. Basic therapy includes resistance exercise and protein and vitamin D supplementation. There is now a simple screening test available for sarcopenia-SARC-F. All persons 60 years and older should be screened for sarcopenia and treated when appropriate.

Undercarboxylated osteocalcin, muscle strength and indices of bone health in older women

We investigated the association between undercarboxylated osteocalcin (ucOC) and lower-limb muscle strength in women over the age of 70years. The study also aims to confirm the association between bone turnover markers and heel ultrasound measures. A post-hoc analysis using data collected as part of a randomized placebo-controlled trial of vitamin D supplementation. An immunoassay was used to quantify total OC (tOC), with hydroxyapatite pre-treatment for ucOC. We determined associations of absolute and relative (ucOC/tOC; ucOC%) measures of ucOC with lower-limb muscle strength, heel ultrasound measures of speed of sound (SOS) and broadband ultrasound attenuation (BUA), bone turnover markers (BTMs; P1NP and CTx) and the acute phase protein alpha-1-antichymotrypsin (α-ACT). ucOC%, but not absolute ucOC concentration, was positively associated with hip flexor, hip abductor and quadriceps muscle strength (all p<0.05). ucOC% was negatively associated with α-ACT (β-coefficient=-0.24, p=0.02). tOC was positively associated with both P1NP and CTx (p<0.001). For each per unit increase in tOC (μg/L) there was a corresponding lower BUA, SOS and SI (β-coefficient = -0.28; -0.23 and -0.23, respectively; all p<0.04). In conclusion, ucOC% is positively associated with muscle strength and negatively associated with α-ACT. These data support a role for ucOC in musculoskeletal interactions in humans. Whilst tOC is associated with bone health, ucOC% and ucOC may also be linked to falls and fracture risk by influencing muscle function.

Sarcopenia, cachexia and aging: diagnosis, mechanisms and therapeutic options - a mini-review

By the year 2050, individuals over the age of 65 years will comprise 20% of the US population. Loss of muscle mass and strength is common in this age group and it is associated with increased dependence, frailty and mortality. Sarcopenia, defined as the loss of muscle mass and function associated with aging, and cachexia, defined as weight loss due to an underlying illness, are muscle wasting disorders of particular relevance in the aging population, but they go largely unrecognized. In this review we highlight the common pathophysiological mechanisms underlying muscle loss in sarcopenia and cachexia, the factors unique to each condition and means of diagnosing and differentiating them clinically. Therapeutic options including exercise, nutritional therapy, androgens and growth hormone as well as their practical limitations are discussed. We also shed light on newer agents being developed as potential therapeutic options for wasting diseases.

Meta-analysis of genome-wide association data identifies novel susceptibility loci for obesity

Obesity is a major public health problem with strong genetic determination. Multiple genetic variants have been implicated for obesity by conducting genome-wide association (GWA) studies, primarily focused on body mass index (BMI). Fat body mass (FBM) is phenotypically more homogeneous than BMI and is more appropriate for obesity research; however, relatively few studies have been conducted on FBM. Aiming to identify variants associated with obesity, we carried out meta-analyses of seven GWA studies for BMI-related traits including FBM, and followed these analyses by de novo replication. The discovery cohorts consisted of 21 969 individuals from diverse ethnic populations and a total of over 4 million genotyped or imputed SNPs. The de novo replication cohorts consisted of 6663 subjects from two independent samples. To complement individual SNP-based association analyses, we also carried out gene-based GWA analyses in which all variations within a gene were considered jointly. Individual SNP-based association analyses identified a novel locus 1q21 [rs2230061, CTSS (Cathepsin S)] that was associated with FBM after the adjustment of lean body mass (LBM) (P = 3.57 × 10(-8)) at the genome-wide significance level. Gene-based association analyses identified a novel gene NLK (nemo-like kinase) in 17q11 that was significantly associated with FBM adjusted by LBM. In addition, we confirmed three previously reported obesity susceptibility loci: 16q12 [rs62033400, P = 1.97 × 10(-14), FTO (fat mass and obesity associated)], 18q22 [rs6567160, P = 8.09 × 10(-19), MC4R (melanocortin 4 receptor)] and 2p25 [rs939583, P = 1.07 × 10(-7), TMEM18 (transmembrane protein 18)]. We also found that rs6567160 may exert pleiotropic effects to both FBM and LBM. Our results provide additional insights into the molecular genetic basis of obesity and may provide future targets for effective prevention and therapeutic intervention.

Frailty consensus: a call to action

Frailty is a clinical state in which there is an increase in an individual's vulnerability for developing increased dependency and/or mortality when exposed to a stressor. Frailty can occur as the result of a range of diseases and medical conditions. A consensus group consisting of delegates from 6 major international, European, and US societies created 4 major consensus points on a specific form of frailty: physical frailty. 1. Physical frailty is an important medical syndrome. The group defined physical frailty as "a medical syndrome with multiple causes and contributors that is characterized by diminished strength, endurance, and reduced physiologic function that increases an individual's vulnerability for developing increased dependency and/or death." 2. Physical frailty can potentially be prevented or treated with specific modalities, such as exercise, protein-calorie supplementation, vitamin D, and reduction of polypharmacy. 3. Simple, rapid screening tests have been developed and validated, such as the simple FRAIL scale, to allow physicians to objectively recognize frail persons. 4. For the purposes of optimally managing individuals with physical frailty, all persons older than 70 years and all individuals with significant weight loss (>5%) due to chronic disease should be screened for frailty.

Sarcopenia: a clinical review

Although sarcopenia has been used to define muscle mass loss in older subjects, muscle mass is not directly linked to muscle function. Recent definitions consider sarcopenia as a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes, such as physical disability, poor quality of life, and death. It is closely linked with physical frailty, and also with other muscle wasting disorders, including cachexia and malnutrition. This review focuses on the incorporation of sarcopenia into clinical practice, reviews case finding and diagnosis of sarcopenia, proposes a syndromic approach for the diagnostic work-up of sarcopenic patients, and looks at intervention trials with physical exercise and nutrition, as drugs to treat this condition are not expected to be available in the near future.

Muscle atrophy in aging and chronic diseases: is it sarcopenia or cachexia?

Cachexia and sarcopenia present several analogies in both the pathogenic mechanisms and the clinical picture. The loss of muscle mass and strength is a hallmark of these two clinical conditions. Although frequently overlapping and often indistinguishable, especially in old individuals, these two conditions should be considered distinct clinical entities. A prompt and accurate patient evaluation, guiding the physician through a proper differential diagnostic procedure and providing the best therapeutic options, is recommended. Given the several commonalities between cachexia and sarcopenia, it is likely that the therapeutic approaches may prove effective in both conditions. This review focuses on the most recent available literature and aims at providing physicians with the correct tools that are available to aid in diagnosing these two different entities that often clinically overlap. Currently available or proposed therapeutic strategies for pre-cachexia, cachexia and sarcopenia are also briefly described.

Bearing arms against osteoarthritis and sarcopenia: when cartilage and skeletal muscle find common interest in talking together

Osteoarthritis, a disease characterized by cartilage degradation, abnormal subchondral bone remodelling and some grade of inflammation, and sarcopenia, a condition of pathological muscle weakness associated with altered muscle mass, strength, and function, are prevalent disorders in elderly people. There is increasing evidence that decline in lower limb muscle strength is associated with knee or hip osteoarthritis in a context of pain, altered joint stability, maladapted postures and defective neuromuscular communication. At the cellular and molecular levels, chondrocytes and myoblasts share common pathological targets and pathways, and the close anatomical location of both cell types suggest a possibility of paracrine communication. In this review, we examine the relationship between osteoarthritis and sarcopenia in the musculoskeletal field, and discuss the potential advantage of concomitant therapies, or how each disorder may benefit from treatment of the other.