Purpose
While some work has been done on Health-Related Quality of Life (HRQoL) in statin users, none has focused specifically on statin-associated muscle symptoms (SAMS) sufferers. The objective was ...to assess self-reported HRQoL, before and after statin withdrawal, in patients reporting SAMS. We hypothesized that the presence of SAMS associated with decreased self-reported physical and mental well-being.
Methods
Patients (50 men/28 women M/W, aged 49 ± 9 years Mean ± SD) in primary cardiovascular prevention were recruited into three cohorts: statin users with (SAMS, 29 M/18W) or without symptoms (No SAMS, 10 M/5W) and controls (11 M/5W). The Short Form 36 Health Survey (SF-36) was used to assess HRQoL. All variables were measured before and after 2 months of statin withdrawal, and repeated measures analyses were used to verify withdrawal and group effects as well as their interaction.
Results
SF-36 physical and mental component scores (respectively, PCS and MCS) were lower in the SAMS group compared with other groups (both
p
< 0.01). Statin withdrawal led to an increase in LDL cholesterol for statin users (+69.0%,
p
< 0.01) and an improvement in well-being in the SAMS group, other groups showing no change. A time x category interaction (
p
= 0.02) was seen for PCS and post hoc analyses showed that statin withdrawal improved PCS and MCS (respectively, +12.5% ES 0.77 and +5.1% ES 0.27, both
p
< 0.05) in the SAMS group.
Conclusion
Patients self-reporting SAMS showed improved HRQoL following drug withdrawal, but this was mirrored by a rise in LDL cholesterol. These findings should be considered by clinicians in the evaluation and follow-up of treatment with statins.
To examine skeletal muscle intracellular triglyceride concentration in different fiber types in relation to obesity.
Skeletal muscle fiber type distribution and intracellular lipid content were ...measured in vastus lateralis samples obtained by needle biopsy from lean and obese individuals.
Seven lean controls (body mass index (BMI) 23.0+/-3.3 kg/m(2); mean+/-s.d.) and 14 obese (BMI 33.7+/-2.7 kg/m(2)) individuals; both groups included comparable proportions of men and women.
Samples were histochemically stained for the identification of muscle fiber types (myosin ATPase) and intracellular lipid aggregates (oil red O dye). The number and size of fat aggregates as well as their concentration within type I, IIA and IIB muscle fiber types were measured. The cellular distribution of the lipid aggregates was also examined.
The size of fat aggregates was not affected by obesity but the number of lipid droplets within muscle fibers was twice as abundant in obese compared to lean individuals. This was seen in type I (298+/-135 vs 129+/-75; obese vs lean, P<0.05), IIA (132+/-67 vs 79+/-29; P<0.05), and IIB (103+/-63 vs 51+/-13; P<0.05) muscle fibers. A more central distribution of lipid droplets was observed in muscle fibers of obese compared to lean subjects (27.2+/-5.7 vs 19.7+/-6.4%; P<0.05).
The higher number of lipid aggregates and the disposition to a greater central distribution in all fiber types in obesity indicate important changes in lipid metabolism and/or storage that are fiber type-independent.
This study examined the relationship between the phenotypic and anthropometric characteristics and the cycling time to exhaustion (Tlim) at the maximal aerobic power output (Pmax). 12 (7 men, 5 ...women) physically-active participants performed a square-wave test at Pmax to determine the maximal time limit. Muscle histochemistry, enzymatic activities and buffer capacity were determined from a vastus lateralis muscle biopsy, lean body mass (LBM) by hydrostatic weighing, and total (TV) and lean (LV) volumes of the thigh by anthropometric measurements. The mean (±SD) Tlim was 235±84 s (score range: 108-425 s). No relationship was found between Tlim and any muscle phenotypes. However, we observed a strong, linear relationship between Tlim and LBM (r=0.84, P<0.05). Thigh TV and LV displayed weaker correlation coefficients with Tlim (r=0.66 and r=0.73, respectively; P<0.05). We further estimated the femur length and found this measure to correlate with Tlim (r=0.81, P<0.05). This study suggests that muscle phenotypes may not be representative of Tlim. Rather, anthropometric characteristics account for such performance by conferring a biomechanical advantage in cycling. We conclude that, in addition to metabolic factors, anthropometric characteristics with reasonable accuracy predict Tlim in cycling, and may account for the large inter-subject variability observed in previous studies.
The chronology of diaphragm and vastus lateralis adaptation in chronic obstructive pulmonary disease (COPD) has not been studied. The hypothesis of this study was that muscle changes would occur ...earlier in the diaphragm than in the vastus lateralis in COPD, a finding that would suggest that local factors would be more important than systemic factors in determining the muscle phenotypic expression, at least in mild-to-moderate disease. The adaptation of the vastus lateralis and diaphragm muscles was evaluated in patients with mild-to-moderate COPD and in subjects with normal pulmonary function. In both groups, the oxidative potential and the number of lipofuscin inclusions were higher in the diaphragm than in the vastus lateralis. Compared to control, the diaphragm in COPD had a higher oxidative capacity and a higher proportion of type I fibres, with a reciprocal decrease in type IIA fibres, while there was no difference in diaphragmatic cross sectional areas, capillarisation and lipofuscin inclusions. No significant differences were found in the vastus lateralis from both groups. In conclusion, these data indicate that the diaphragm in controls and in chronic obstructive pulmonary disease has a higher oxidative potential than the vastus lateralis, and that muscle adaptation occurs earlier in the diaphragm than in the vastus lateralis in mild-to-moderate chronic obstructive pulmonary disease.
Bien que l’obésité soit associée à un risque accru de maladies cardiovasculaires et de mortalité, des études ont rapporté l’existence d’individus obèses ayant un profil métabolique sain ou « ...metabolically healthy obese » (MHO). Ce phénotype peut être évalué par de nombreuses classifications qui ne font toujours pas l’objet d’un consensus. Cette revue présente les classifications les plus utilisées, la prévalence et les principales caractéristiques des sujets MHO, leur morbi- mortalité à court et long terme ainsi que l’impact d’interventions de perte de poids chez ces individus. Although obesity is associated with an increased risk of cardiovascular disease and related mortality, studies have reported the existence of obese individuals with a meta- bolically healthy obese profile named MHO. This phenotype can be evaluated by numerous classifications, which are still matter of debate. This review presents the most commonly used classifications, the prevalence and main characteristics of MHO subjects, their short- and long-term morbidity and mortality, and the impact of different weight loss interventions in these individuals.
The age-associated reduction in muscle mass is well characterized; however, less is known regarding the mechanisms responsible for the decline in oxidative capacity also observed with advancing age. ...The purpose of the current study was therefore to compare mitochondrial gene expression and protein content between young and old recreationally active, and older highly active individuals. Muscle biopsies were obtained from the vastus lateralis of young males (YG: 22 ± 3 years) and older (OG: 67 ± 2 years) males not previously engaged in formal exercise and older male master cyclists (OT: 65 ± 5 years) who had undertaken cycling exercise for 32 ± 17 years. Comparison of gene expression between YG, OG, and OT groups revealed greater expression of mitochondrial-related genes, namely, electron transport chain (ETC) complexes II, III, and IV (p < .05) in OT compared with YG and OG. Gene expression of mitofusion (MFN)-1/2, mitochondrial fusion genes, was greater in OT compared with OG (p < .05). Similarly, protein content of ETC complexes I, II, and IV was significantly greater in OT compared with both YG and OG (p < .001). Protein content of peroxisome proliferator-activated receptor gamma, coactivator 1 α (PGC-1α), was greater in OT compared with YG and OG (p < .001). Our results suggest that the aging process per se is not associated with a decline in gene expression and protein content of ETC complexes. Mitochondrial-related gene expression and protein content are substantially greater in OT, suggesting that exercise-mediated increases in mitochondrial content can be maintained into later life.
Maintenance of reduced or elevated body weight results in respective decreases or increases in energy expended in physical activity, defined as 24-h energy expenditure excluding resting energy ...expenditure and the thermic effect of feeding, beyond those attributable to weight change. We examined skeletal muscle work efficiency by graded cycle ergometry and, in some subjects, rates of gastrocnemius muscle ATP flux during exercise by magnetic resonance spectroscopy (MRS), in 30 subjects (15 males, 15 females) at initial weight and 10% below initial weight and in 8 subjects (7 males, 1 female) at initial weight and 10% above initial weight to determine whether changes in skeletal muscle work efficiency at altered body weight were correlated with changes in the energy expended in physical activity. At reduced weight, muscle work efficiency was increased in both cycle ergometry mean (SD) change = +26.5 (26.7)%, P < 0.001 and MRS ATP flux change = -15.2 (23.2)%, P = 0.044 studies. Weight gain resulted in decreased muscle work efficiency by ergometry mean (SD) change = -17.8 (20.5)%, P = 0.043. Changes in muscle efficiency at altered body weight accounted for 35% of the change in daily energy expended in physical activity.
The associations of the C34T polymorphism of the adenosine monophosphate deaminase 1 (AMPD1) gene with cardiorespiratory phenotypes were tested during cycling exercise at absolute and relative power ...outputs progressing to exhaustion before and after endurance training for 20 wk in the HERITAGE Family Study cohort (n = 779). Since no blacks were mutant homozygotes (TT), only whites were considered for analysis (400 normal homozygotes, CC; 97 heterozygotes, CT; and 6 TT). For sedentary state, cycling at the absolute power output of 50 W resulted in a higher rating of perceived exertion in TT (P < 0.0001). At the relative intensity of 60% of Vo(2 max), stroke volume was lower in TT (P < 0.05). Maximal values for power output, systolic blood pressure, heart rate, Vco(2), and respiratory exchange ratio were lower in TT (P < 0.05). The cardiorespiratory training response at 50 W and at 60% of Vo(2 max) was similar across C34T-AMPD1 genotypes. However, the maximal values for ventilation, Vo(2), and Vco(2) during exercise increased less in TT (P < 0.01). The results indicate that subjects with the TT genotype at the C34T AMPD1 gene have diminished exercise capacity and cardiorespiratory responses to exercise in the sedentary state. Furthermore, the training response of ventilatory phenotypes during maximal exercise is more limited in TT.
Objective: To compare the relationships between markers of total and regional adiposity with muscle fat infiltration in type 1 diabetic and type 2 diabetic subjects and their respective nondiabetic ...controls, and to document these relationships in type 1 diabetic subjects. Design: Cross-sectional study. Subjects: In total, 86 healthy, with type 1 diabetes, type 2 diabetes or control subjects. Each diabetic group was matched for age, sex and body mass index with its respective nondiabetic control group. Measurements: Measures of body composition (hydrodensitometry), fat distribution (waist circumference, abdominal and mid-thigh computed tomography scans) and blood lipid profiles were assessed. Results: Low attenuation mid-thigh muscle surface correlated similarly with markers of adiposity and body composition in all groups, regardless of diabetes status, except for visceral adipose tissue and waist circumference. Indeed, relationships between visceral adiposity and muscle adiposity were significantly stronger in type 2 vs type 1 diabetic subjects (P<0.05 for comparison of slopes). In addition, in well-controlled type 1 diabetic subjects (mean HbA1c of 6.8%), daily insulin requirements tended to correlate with low attenuation mid-thigh muscle surface, a specific component of fat-rich muscle (r=0.36, P=0.08), but not with glycemic control (HbA1c). Conclusion: This study suggests that the relationship of central adiposity and muscle adiposity is modulated by diabetes status and is stronger in the insulin resistant diabetes type (type 2 diabetes). In well-controlled nonobese type 1 diabetic subjects, the relationship between muscle fat accumulation and insulin sensitivity was also maintained.
Abstract Aim The ongoing obesity epidemic is associated with numerous health problems related to altered metabolic function. Among these is type 2 diabetes, characterized by lowered insulin ...sensitivity (IS). Consequently, the development of simple indices to assess IS has research and clinical importance. The SIis OGTT, a new index of IS, was recently described by Bastard et al. (Diabetes & Metabolism 2007;33:261–8), and validated in sedentary, non-diabetic, overweight and obese postmenopausal women. The aim of the present study was to validate the index in men. Methods The data used in this project came from sedentary men ( n = 36), aged 34–53 years, all of whom underwent a hyperinsulinaemic–euglycaemic clamp and 2-hour oral glucose tolerance test (OGTT). Correlations with M/I (glucose infusion rate GIR divided by insulin concentration), GIR and GIR divided by fat-free mass (FFM) were obtained by four well-known indices (HOMA, QUICKI, Cederholm and Matsuda) as well as with the new SIis OGTT index. Pearson correlations and Bland–Altman analyses were obtained for every index versus clamp value. Results The best correlate of IS in the present study was the SIis OGTT ( r = 0.84, P < 0.0001). The agreement of this method with the hyperinsulinaemic–euglycaemic clamp, as assessed by Bland–Altman plots, was similar to those of the other indices and to those previously described in postmenopausal women. Conclusion The new index proposed by Bastard et al. is as good a predictor of IS in sedentary men as the other commonly used indices, and appears to be as reliable in this population as it was in the original study of postmenopausal women.
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