Advancing our understanding of skeletal muscle across the lifecourse: Protocol for the MASS_Lifecourse study and characteristics of the first 80 participants.

INTRODUCTION: Sarcopenia, the age-related loss of skeletal muscle strength and mass, carries a significant burden for affected individuals. There has been little investigation of sarcopenia using experimental medicine techniques to study human muscle tissue in detail. The aim of the Muscle Ageing Sarcopenia Studies Lifecourse (MASS_Lifecourse) study is to recruit up to 160 participants, equally divided between females and males between ages 45 and 85 years for detailed phenotyping of skeletal muscle health. Here we describe the protocol for the study and the characteristics of the first 80 participants. METHODS: We are recruiting participants from three sources in the north-east of England. Study fieldwork comprises a home visit (or videocall) for consent and assessment of health, cognition, lifestyle, and wellbeing. This is followed by a visit to a clinical research facility for assessment of sarcopenia status and collection of samples including a vastus lateralis muscle biopsy. We produced descriptive statistics for the first 80 participants, including expressing their grip strength relative to normative data in the form of Z-scores. RESULTS: The first 80 participants (53.8 % female) covered the target ages, ranging from 48 to 84 years. They were regularly physically active, reported good physical function and had a prevalence of sarcopenia (including probable sarcopenia) of 11.3 % based on the revised European consensus. Their grip strength was similar to that in the general population, with a mean Z-score of 0.09 standard deviations (95 % CI: -1.64, 1.83) above that expected. CONCLUSIONS: The MASS_Lifecourse study combines comprehensive health and lifestyle data with a range of biological samples including skeletal muscle. The findings from planned analyses should contribute to improvements in the diagnosis, treatment, and prevention of sarcopenia.

The assessment of sarcopenia and the frailty phenotype in the outpatient care of older people: implementation and typical values obtained from the Newcastle SarcScreen project.

PURPOSE: Sarcopenia and the frailty phenotype both indicate older adults at risk of adverse health outcomes and yet are not widely assessed in practice. We developed the Newcastle SarcScreen to enable assessment of these two ageing syndromes during clinical care. In the setting of our Older People's Medicine Day Unit, our aims were to describe the implementation of the SarcScreen and to examine the typical values obtained. METHODS: The SarcScreen comprised height, weight, questions (three on the Fried frailty phenotype and five on the SARC-F questionnaire), grip strength and gait speed. We analysed data from 552 patients completing the SarcScreen. We expressed grip strength as Z-scores (number of standard deviations above the mean expected for a patient's age and sex). RESULTS: It was possible to implement the SarcScreen. In 552 patients (65.9% females) with mean age 80.1 (7.7) years, grip strength was feasible in 98.2% and gait speed in 82.1%. Gait speed was typically not assessed due to mobility impairment. Most patients had weak grip strength (present in 83.8%), slow gait speed (88.8%) and the frailty phenotype (66.2%). We found a high prevalence of probable sarcopenia and the frailty phenotype across all age groups studied. This was reflected by low grip strength Z-scores, especially at younger ages: those aged 60-69 had grip strength 2.7 standard deviations (95% CI 2.5-2.9) below that expected. CONCLUSION: It is possible to implement an assessment of sarcopenia and the frailty phenotype as part of the routine outpatient care of older people.

The identification of probable sarcopenia in early old age based on the SARC-F tool and clinical suspicion: findings from the 1946 British birth cohort.

PURPOSE: The European Working Group on Sarcopenia in Older People 2 (EWGSOP2) consensus definition introduced the concept of probable sarcopenia as a basis on which to begin treatment. Our aims were to describe the prevalence of probable sarcopenia in older adults and to investigate the utility of (1) the SARC-F tool and (2) clinical risk factors for the identification of those likely to have probable sarcopenia. METHODS: We used data from the 1946 British birth cohort at age 69, with 1686 participants included in the analyses. We used the EWGSOP2 cut points for weak grip strength and slow chair rise time, with the presence of one or both indicating probable sarcopenia. We examined the sensitivity and specificity of the SARC-F tool for probable sarcopenia. We also examined associations between clinical risk factors and probable sarcopenia. RESULTS: The prevalence of probable sarcopenia was 19%. A SARC-F score of ≥ 4 had low sensitivity (15%) and high specificity (99%) for probable sarcopenia, whereas a score of ≥ 1 had higher sensitivity (65%) and reasonable specificity (72%). Three clinical risk factors were independently associated with probable sarcopenia: polypharmacy [OR 2.7 (95% CI 1.7, 4.2)], lower body osteoarthritis [OR 1.8 (95% CI 1.3, 2.6)] and physical inactivity [OR of 2.1 (95% CI 1.5, 2.8)]. CONCLUSION: We have shown that EWGSOP2 probable sarcopenia is common in community-dwelling adults in early old age. Those with any positive responses to the questions in the SARC-F tool, a history of polypharmacy, lower body osteoarthritis or physical inactivity should be prioritised for the assessment of muscle strength.

The recent secular trend in grip strength among older adults: findings from the English Longitudinal Study of Ageing.

PURPOSE: Weaker grip strength in older adults is associated with adverse health outcomes and is a key component of sarcopenia. The secular trend of grip strength is, therefore, relevant in the setting of ageing populations. A recent study suggested differences in this trend among countries in mainland Europe. We used data from the English Longitudinal Study of Ageing (ELSA) to investigate the recent secular trend of older English adults. METHODS: We used data on participants aged 50-89 having their first measurement of grip strength in waves 2 (2002/2003), 4 (2008/2009) or 6 (2012/2013) of ELSA. Grip was measured using a Smedley dynamometer. We expressed grip values as Z-scores (number of standard deviations above the age and gender mean from normative data) for use in linear regression analyses examining the annual secular trend after adjustment for potential confounders. RESULTS: We included a total of 11,476 participants from the three waves of ELSA. Grip strength declined across the three waves, with mean (SD) Z-scores of 0.01 (0.94), - 0.06 (0.97) and - 0.20 (0.98) in waves 2, 4 and 6, respectively. The annual Z-score decline after adjustments was 0.03 SDs (95% CI 0.02, 0.03) per year. CONCLUSION: We saw evidence of a recent slight decline in the grip strength of older English adults. Over the 9-year period of this study, the decline seen is equivalent to 65-year-olds' mean strength declining to that previously seen in individuals at age 69. Further monitoring of secular trends in grip strength and investigation of possible causes are warranted.

Mitochondrial respiratory chain function and content are preserved in the skeletal muscle of active very old men and women.

INTRODUCTION: The loss of mitochondrial function and content have been implicated in sarcopenia although they have been little studied in the very old, the group in which sarcopenia is most common. In this pilot study, our aim was to determine if mitochondrial respiratory chain function and content are preserved among healthy 85-year-olds. METHODS: We recruited 19 participants (11 female) through their general practitioner and assessed their medical history, functional status and self-reported physical activity. We identified sarcopenia using grip strength, Timed Up-and-Go and bioimpedance analysis. We assessed mitochondrial respiratory chain function using phosphorous magnetic resonance spectroscopy, estimating τ1/2 PCr, the recovery half-time of phosphocreatine in the calf muscles following a bout of aerobic exercise. We performed a biopsy of the vastus lateralis muscle and assessed mitochondrial respiratory chain content by measuring levels of subunits of complex I and IV of the respiratory chain, expressed as Z-scores relative to that in young controls. RESULTS: Participants had a median (IQR) of 2 (1,3) long-term conditions, reported regular aerobic physical activity, and one participant (5.3%) had sarcopenia. Sixteen participants completed the magnetic resonance protocol and the mean (SD) τ1/2 PCr of 35.6 (11.3) seconds was in keeping with preserved mitochondrial function. Seven participants underwent muscle biopsy and the mean fibre Z-scores were -0.7 (0.7) and -0.2 (0.4) for complexes I and IV, respectively, suggesting preserved content of mitochondrial respiratory chain enzymes. CONCLUSION: Muscle mitochondrial respiratory chain function and content are preserved in a sample of active, well-functioning 85-year-olds, among whom sarcopenia was uncommon. The results from this study will help inform future work examining the association between muscle mitochondrial deficiency and sarcopenia.

Can measures of physical performance in mid-life improve the clinical prediction of disability in early old age? Findings from a British birth cohort study.

BACKGROUND: Poor performance in physical tests such as grip strength and walking speed is a risk factor for disability in old age, although whether such measures improve the discrimination of clinical prediction models when traditional clinical risk factors are already known is not clear. The prevalence of disability in mid-life is relatively low and hence screening in this age group may present an opportunity for early identification of those at increased future risk who may benefit most from preventative interventions. METHODS: Data were drawn from two waves of the Medical Research Council National Survey of Health and Development. We examined whether several chronic conditions, poor health behaviours and lower scores on three measures of physical performance (grip strength, chair rise speed and standing balance time) at age 53 were associated with self-reported mobility and/or personal care disability at age 69. We used the area under the curve statistic (AUC) to assess model discrimination. RESULTS: At age 69, 44% (826/1855) of participants reported mobility and/or personal care disability. Our final clinical prediction model included sex, knee osteoarthritis, taking 2+ medications, smoking, increased BMI and poor performance in all three physical tests, with an AUC of 0.740 compared with 0.708 for a model which did not include the performance measures. CONCLUSION: Measures of physical performance in midlife improve discrimination in clinical prediction models for disability over 16 years. Importantly, these and similar measures are also potential targets of future diet, exercise and pharmacological intervention in mid-life.

Physical activity among hospitalised older people: insights from upper and lower limb accelerometry.

BACKGROUND: Few studies have explored the activity levels of hospitalised older people and the intra-daily activity patterns in this group have not been described. AIMS: To describe the quantity and daily pattern of physical activity among hospitalised older people using two accelerometers: the ankle-worn StepWatch Activity Monitor (SAM), and the wrist-worn GENEActiv. METHODS: This cross-sectional observational study was conducted on the acute medical wards for older people in one UK hospital. INCLUSION CRITERIA: participants aged ≥ 70 years, and able to mobilise prior to admission. Participants wore both devices for up to seven consecutive days, or until hospital discharge, whichever was sooner. Intra-daily activity levels were analysed hourly over each 24 h period. RESULTS: 38 participants (mean age 87.8 years, SD 4.8) had their activity levels measured using both devices. The SAM median daily step count was 600 (IQR 240-1427). Intra-daily activity analysis showed two peak periods of ambulatory activity between 9 am-11 am and 6 pm-7 pm. With physical activity defined as ≥ 12 milli-g (GENEActiv), the median time spent above this cut-off point was 4.2 h. 62% of this activity time was only sustained for 1-5 min. Acceptability of both devices was high overall, but the wrist-worn device (96%) was more acceptable to patients than the ankle-worn device (83%). CONCLUSION: Activity levels of these hospitalised older people were very low. Most physical activity was sustained over short periods. The intra-daily pattern of activity is an interesting finding which can help clinicians implement time-specific interventions to address the important issue of sedentary behaviour.

Potential economic impacts from improving breastfeeding rates in the UK.

RATIONALE: Studies suggest that increased breastfeeding rates can provide substantial financial savings, but the scale of such savings in the UK is not known. OBJECTIVE: To calculate potential cost savings attributable to increases in breastfeeding rates from the National Health Service perspective. DESIGN AND SETTINGS: Cost savings focussed on where evidence of health benefit is strongest: reductions in gastrointestinal and lower respiratory tract infections, acute otitis media in infants, necrotising enterocolitis in preterm babies and breast cancer (BC) in women. Savings were estimated using a seven-step framework in which an incidence-based disease model determined the number of cases that could have been avoided if breastfeeding rates were increased. Point estimates of cost savings were subject to a deterministic sensitivity analysis. RESULTS: Treating the four acute diseases in children costs the UK at least £89 million annually. The 2009-2010 value of lifetime costs of treating maternal BC is estimated at £959 million. Supporting mothers who are exclusively breast feeding at 1 week to continue breast feeding until 4 months can be expected to reduce the incidence of three childhood infectious diseases and save at least £11 million annually. Doubling the proportion of mothers currently breast feeding for 7-18 months in their lifetime is likely to reduce the incidence of maternal BC and save at least £31 million at 2009-2010 value. CONCLUSIONS: The economic impact of low breastfeeding rates is substantial. Investing in services that support women who want to breast feed for longer is potentially cost saving.

Birth weight and muscle strength: a systematic review and meta-analysis.

OBJECTIVE: Lower muscle strength is associated with a range of adverse health outcomes in later life. The variation in muscle strength between individuals is only partly accounted for by factors in adult life such as body size and physical activity. The aim of this review was to assess the strength of the association between intrauterine development (indicated by birth weight) and subsequent muscle strength. DESIGN: Systematic review and meta-analysis of studies that assessed the association between birth weight and subsequent muscle strength. RESULTS: Nineteen studies met inclusion criteria with 17 studies showing that higher birth weight was associated with greater muscle strength. Grip strength was used as a single measure of muscle strength in 15 studies. Meta-analysis (13 studies, 20 481 participants, mean ages 9.3 to 67.5) showed a 0.86 kg (95% CI 0.58, 1.15) increase in muscle strength per additional kilogram of birth weight, after adjustment for age, gender and height at the time of strength measurement. CONCLUSION: This review has found consistent evidence of a positive association between birth weight and muscle strength which is maintained across the lifecourse. Future work will be needed to elucidate the biological mechanisms underlying this association, but it suggests the potential benefit of an early intervention to help people maintain muscle strength in later life.

Grip strength at four years in relation to birth weight.

Consistent positive relationships have been found between birth weight and grip strength in adults but evidence in children is limited. In a prospective general population birth cohort (Southampton Women's Survey) grip strength and anthropometry (height and weight) were measured in 968 children at age 4 years. Mean (standard deviation (S.D.)) birth weight was 3.48 (0.52) kg. Birth weight, adjusted for sex and gestational age, was positively associated with grip strength (ß = 0.22 kg/S.D. increase in adjusted birth weight; 95% CI 0.11, 0.34). The relationship was attenuated after adjustment for current height and weight such that it became non-significant (ß = 0.03 kg/S.D. increase in adjusted birth weight; 95% CI -0.08, 0.14), suggesting that body size may be on the causal pathway. Early influences on muscle development appear to impact on grip strength in children as well as adults.

Grip strength at 4 years in relation to birth weight.

Consistent positive relationships have been found between birth weight and grip strength in adults but evidence in children is limited. In a prospective general population birth cohort (Southampton Women's Survey), grip strength and anthropometry (height and weight) were measured in 968 children at the age of 4 years. Mean (standard deviation (s.d.)) birth weight was 3.48 (0.52) kg. Birth weight, adjusted for sex and gestational age, was positively associated with grip strength (ß = 0.22 kg/s.d. increase in adjusted birth weight; 95% CI 0.11, 0.34). The relationship was attenuated after adjustment for current height and weight such that it became non-significant (ß = 0.03 kg/s.d. increase in adjusted birth weight; 95% CI-0.08, 0.14), suggesting that body size may be on the causal pathway. Early influences on muscle development appear to impact on grip strength in children, as well as adults.

In-vivo and in-vitro histological evaluation of two commercially available acellular dermal matrices.

PURPOSE: Post-herniation abdominal wall repair can be performed with synthetic or biologic meshes. Synthetics have been associated with complications, so biologics are promising alternatives. The methods used to decellularize biological matrices may affect the extracellular components. This study evaluated the post-implantation biological response of two allogenic acellular dermal matrices (ADMs) in a hernia model. METHODS: Testing was conducted with two ADMs from different manufacturers: RTI Biologics (ADM-R) and LifeCell (ADM-L). Samples were evaluated for collagen IV, glycosaminoglycans (GAGs), and elastin before implantation. Samples were also used to repair bilateral full-thickness defects in rat abdominal walls. Pathologist evaluations included explant dimensions, inflammation, neovascularization, mature implant tissue, fibrosis, encapsulation, necrosis, mineralization, adhesions, granulomas, and hemorrhages at four and eight weeks post-implantation. RESULTS: GAG distribution in ADM-R samples was more consistent with native dermis than that in ADM-L samples. Collagen IV was visible in ADM-R, but not in ADM-L. The four-week ADM-R explants showed primarily lymphocytic infiltrates, and less inflammation at eight weeks. The four-week ADM-L explants showed primarily lymphocytic infiltrates, and sustained inflammation at eight weeks. Fibroplasia at four and eight weeks was higher in ADM-L than in ADM-R. Encapsulation, mature connective tissue, and vascular profile scores were comparable between groups. Picrosirius red image analysis showed no significant differences between groups. CONCLUSIONS: The post-processing matrix characterization and in-vivo response showed notable differences in these ADMs, despite similar allogenic origin. Future investigations into the different matrix composition with regard to fibrosis and inflammation are warranted.

Incidence of trampoline related pediatric fractures in a large district general hospital in the United Kingdom: lessons to be learnt.

AIM: To test the observation that the incidence of trampoline related pediatric fractures is increasing-both nationally and in a large district general hospital. METHOD: A retrospective analysis was undertaken of patient records establishing mechanism of injury of pediatric fractures over three consecutive summers from 2000-03. Theatre records of fractures treated operatively were used as the initial data source. RESULTS: A statistically significant increase in trampoline related injuries was discovered. This reflects the rising incidence of injuries from national data and furthermore corresponds to the growing popularity of domestic use trampolines in the UK. CONCLUSION: The incidence of injuries is increasing. There are lessons to be learnt from existing work from countries where trampoline prevalence has been greater for longer. The authors recommend various safety measures that may reduce children's injuries.

The use of skull X-rays in the accident and emergency department.

The notes of all patients attending the accident and emergency department at the Royal Berkshire Hospital with a head injury from 1-30 September 1999 were analysed for the indications for skull X-ray, the report on film, and the outcome of the consultation. Using the existing Royal Berkshire Hospital guidelines, 50% (193/385) of all patients had skull X-rays performed. One fracture was detected. If the recent guidelines from The Royal College of Surgeons of England Working Party for the use of skull X-rays in institutions which possess a CT scanner were applied, the number of skull X-rays performed would reduce from 193 to 14 without detriment to any patient.

A potent small molecule, nonpeptide inhibitor of cathepsin K (SB 331750) prevents bone matrix resorption in the ovariectomized rat.

Inhibition of the cyteine proteinase, cathepsin K (E.C. 3.4.22.38) has been postulated as a means to control osteoclast-mediated bone resorption. The preferred animal models for evaluation of antiresorptive activity are in the rat. However, the development of compounds that inhibit rat cathepsin K has proven difficult because the human and rat enzymes differ in key residues in the active site. In this study, a potent, nonpeptide inhibitor of rat cathepsin K (K(i) = 4.7 nmol/L), 5-(2-morpholin-4-yl-ethoxy)-benzofuran-2-carboxylic acid ((S)-3-methyl-1-(3-oxo-1-[2-(3-pyridin-2-yl-phenyl)-ethenoyl]-azepan-4-ylcarbanoyl)-butyl)-amide (SB 331750), is described, which is efficacious in rat models of bone resorption. SB 331750 potently inhibited human cathepsin K activity in vitro (K(i) = 0.0048 nmol/L) and was selective for human cathepsin K vs. cathepsins B (K(i) = 100 nmol/L), L (0.48 nmol/L), or S (K(i) = 14.3 nmol/L). In an in situ enzyme assay, SB 331750 inhibited osteoclast-associated cathepsin activity in tissue sections containing human osteoclasts (IC(50) approximately 60 nmol/L) and this translated into potent inhibition of human osteoclast-mediated bone resorption in vitro (IC(50) approximately 30 nmol/L). In vitro, SB 331750 partially, but dose-dependently, prevented the parathyroid hormone-induced hypercalcemia in an acute rat model of bone resorption. To evaluate the ability of SB 331750 to inhibit bone matrix degradation in vivo, it was administered for 4 weeks at 3, 10, or 30 mg/kg, intraperitoneally (i.p.), u.i.d. in the ovariectomized (ovx) rat. Both 10 and 30 mg/kg doses of compound prevented the ovx-induced elevation in urinary deoxypyridinoline and prevented the ovx-induced increase in percent eroded perimeter. Histological evaluation of the bones from compound-treated animals indicated that SB 331750 retarded bone matrix degradation in vivo at all three doses. The inhibition of bone resorption at the 10 and 30 mg/kg doses resulted in prevention of the ovx-induced reduction in percent trabecular area, trabecular number, and increase in trabecular spacing. These effects on bone resorption were also reflected in inhibition of the ovx-induced loss in trabecular bone volume as assessed using microcomputerized tomography (microCT; approximately 60% at 30 mg/kg). Together, these data indicate that the cathepsin K inhibitor, SB 331750, prevented bone resorption in vivo and this inhibition resulted in prevention of ovariectomy-induced loss in trabecular structure.

Identification and initial characterization of 5000 expressed sequenced tags (ESTs) each from adult human normal and osteoarthritic cartilage cDNA libraries.

OBJECTIVE: To prepare, sequence and analyse adult human cartilage cDNA libraries to study the gene expression pattern between normal and osteoarthritic cartilage. METHODS: Poly A(+)RNA from adult human normal and osteoarthritic articular cartilage was isolated and used to prepare cDNA libraries. Approximately 5000 ESTs from each library were sequenced and analysed using bioinformatic tools. The expression of select genes was confirmed by Northern blot and in situ hybridization analysis. RESULTS: Multiple gene families including several classical cartilage matrix protein encoding genes were identified. Approximately 28-40% of the genes sequenced from these libraries were novel, while half of the genes encoded known proteins and 4-6% of the genes encoded novel homologs of known proteins. Several known genes, whose expression has not been reported previously in cartilage, were also identified. We have confirmed the cartilage expression of three known (CTGF, CTGF-L and clusterin) and two novel homologs of known genes (PCPE-2 and Gal-Nac transferase) by Northern blot and in situ hybridization analysis. CONCLUSION: This is the first report of the preparation and sequencing of cDNA libraries from adult human normal and osteoarthritic articular cartilage. Further analysis of genes identified from these libraries may provide molecular targets for diagnosis and/or treatment of osteoarthritis (OA).

Azepanone-based inhibitors of human and rat cathepsin K.

The synthesis, in vitro activities, and pharmacokinetics of a series of azepanone-based inhibitors of the cysteine protease cathepsin K (EC 3.4.22.38) are described. These compounds show improved configurational stability of the C-4 diastereomeric center relative to the previously published five- and six-membered ring ketone-based inhibitor series. Studies in this series have led to the identification of 20, a potent, selective inhibitor of human cathepsin K (K(i) = 0.16 nM) as well as 24, a potent inhibitor of both human (K(i) = 0.0048 nM) and rat (K(i,app) = 4.8 nM) cathepsin K. Small-molecule X-ray crystallographic analysis of 20 established the C-4 S stereochemistry as being critical for potent inhibition and that unbound 20 adopted the expected equatorial conformation for the C-4 substituent. Molecular modeling studies predicted the higher energy axial orientation at C-4 of 20 when bound within the active site of cathepsin K, a feature subsequently confirmed by X-ray crystallography. Pharmacokinetic studies in the rat show 20 to be 42% orally bioavailable. Comparison of the transport of the cyclic and acyclic analogues through CaCo-2 cells suggests that oral bioavailability of the acyclic derivatives is limited by a P-glycoprotein-mediated efflux mechanism. It is concluded that the introduction of a conformational constraint has served the dual purpose of increasing inhibitor potency by locking in a bioactive conformation as well as locking out available conformations which may serve as substrates for enzyme systems that limit oral bioavailability.

Biosynthesis and processing of cathepsin K in cultured human osteoclasts.

Cathepsin K (cat K) is the major cysteine protease expressed in osteoclasts and is thought to play a key role in matrix degradation during bone resorption. However, little is known regarding the synthesis, activation, or turnover of the endogenous enzyme in osteoclasts. In this study, we show that mature cat K protein and enzyme activity are localized within osteoclasts. Pulse-chase experiments revealed that, following the synthesis of pro cat K, intracellular conversion to the mature enzyme occurred in a time-dependent manner. Subsequently, the level of mature enzyme decreased. Little or no cat K was observed in the culture media at any timepoint. Pretreatment of osteoclasts with either chloroquine or monensin resulted in complete inhibition of the processing of newly synthesized cat K. In addition, pro cat K demonstrated susceptibility to treatment with N-glycosidase F, suggesting the presence of high-mannose-containing oligosaccharides. Treatment of osteoclasts with the PI3-kinase inhibitor, Wortmannin (WT), not only prevented the intracellular processing of cat K but also resulted in the secretion of proenzyme into the culture media. Taken together, these results suggest that the biosynthesis, processing, and turnover of cat K in human osteoclasts is constitutive and occurs in a manner similar to that of other known cysteine proteases. Furthermore, cat K is not secreted as a proenzyme, but is processed intracellularly, presumably in lysosomal compartments prior to the release of active enzyme into the resorption lacunae.