1,720,988 research outputs found
Optimizing PCSK9 inhibitor therapy: Understanding and managing suboptimal LDL-C response in clinical practice
No full textProprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9-i) represent a major advancement in lipid-lowering therapy, offering robust reductions in low-density lipoprotein cholesterol (LDL-C), and now play a pivotal role in lipid management, especially for patients with atherosclerotic cardiovascular disease at high or very high risk. Despite their proven efficacy in clinical trials, a subset of patients exhibits a suboptimal LDL-C response, especially in real-world settings. Under-response may result from insufficient drug exposure due to non-adherence, suboptimal injection technique, or discontinuation of background lipid-lowering therapy, and biological factors that limit drug efficacy despite adequate exposure. This review explores the frequency and mechanisms of under-response to PCSK9-i, and provide a practical guide for clinicians to identify and address causes of PCSK9-i under-response, ensuring appropriate intervention for a sustained cardiovascular risk reduction
Contraction and nutrition interaction promotes anabolism in cachectic muscle
No full textPURPOSE OF REVIEW:
Cachexia is a disease-related multifactorial syndrome characterized by inflammation, massive muscle protein catabolism and carbohydrate and lipid metabolism disorder.Several studies tried to define the impact of either nutrition or physical exercise (single approach strategy) or their combination (multimodal approach strategy) on prevention and/or treatment of muscle wasting in cachectic patients.
RECENT FINDINGS:
Single approach strategies (i.e. nutrition or physical exercise) have the potential of preventing and improving features of the cachexia syndrome possibly with a differential impact according to the underlying disease. Limited information is available on the beneficial effect of multimodal approach strategies.
SUMMARY:
Multimodal approaches appear to be more effective than those based on single interventions in physiological condition and in cachectic patients with COPD or chronic kidney disease. Further studies, however, are required in cachexia induced by heart failure, cancer and critical illness
High-protein diet with excess leucine prevents inactivity-induced insulin resistance in women
Full text linkBackground and aims: Muscle inactivity leads to muscle atrophy and insulin resistance. The branched-chain amino acid (BCAA) leucine interacts with the insulin signaling pathway to modulate glucose metabolism. We have tested the ability of a high-protein BCAA-enriched diet to prevent insulin resistance during long-term bed rest (BR). Methods: Stable isotopes were infused to determine glucose and protein kinetics in the postabsorptive state and during a hyperinsulinemic-euglycemic clamp in combination with amino acid infusion (Clamp + AA) before and at the end of 60 days of BR in two groups of healthy, young women receiving eucaloric diets containing 1 g of protein/kg per day (n = 8) or 1.45 g of protein/kg per day enriched with 0.15 g/kg per day of BCAAs (leucine/valine/isoleucine = 2/1/1) (n = 8). Body composition was determined by Dual X-ray Absorptiometry. Results: BR decreased lean body mass by 7.6 ± 0.3 % and 7.2 ± 0.8 % in the groups receiving conventional or high protein-BCAA diets, respectively. Fat mass was unchanged in both groups. At the end of BR, percent changes of insulin-mediated glucose uptake significantly (p = 0.01) decreased in the conventional diet group from 155 ± 23 % to 84 ± 10 % while did not change significantly in the high protein-BCAA diet group from 126 ± 20 % to 141 ± 27 % (BR effect, p = 0.32; BR/diet interaction, p = 0.01; Repeated Measures ANCOVA). In contrast, there were no BR/diet interactions on proteolysis and protein synthesis Clamp + AA changes in the conventional diet and the high protein-BCAA diet groups. Conclusion: A high protein-BCAA enriched diet prevented inactivity-induced insulin resistance in healthy women
Exercise-mediated reactive oxygen species generation in athletes and in patients with chronic disease
No full textComment on
Redox status alterations during the competitive season in élite soccer players: focus on peripheral leukocyte-derived ROS
BIOMARKERS TO DEFINE OPTIMAL PROTEIN REQUIREMENT
Full text link2013/2014Dietary proteins are the source of the amino acids required by the body for tissue growth and maintenance. The Population Reference Intake (PRI) for proteins, as defined by the European Food Safety Authority (EFSA) for healthy adults, including the elderly, is 0.83 g/kg body weight/day. This amount is defined on the net balance of body protein (or “nitrogen balance”, given by the difference between dietary nitrogen intake and losses) equivalent to 0.66 g/kg/day plus a safety factor for interpersonal variability and differences in proteins quality of mixed diets. The PRI, however, is the minimum daily amount of protein needed to maintain the nitrogen balance and avoid a progressive loss of lean body mass in healthy people with moderate physical activity. Therefore nitrogen balance may not be adequate to define protein requirement in adults and especially in ageing characterized by loss of muscle mass and function (sarcopenia). Furthermore until recently the prevalent idea was that a protein intake above PRI had no further benefits and on the contrary could impair health. These believes are now under discussion, diets with higher protein intake have been shown beneficial in the prevention and treatment of conditions such as sarcopenia, COPD and type 2 diabetes mellitus. There is a need of more precise methods to define protein requirement.
AIM. The aim of the present thesis is to investigate in human healthy volunteers new biomarkers adequate to define optimal protein intake. Recent studies have determined protein needs by measuring whole-body protein metabolism using stable labeled isotope-amino acids.
METHODS. Our research group has applied two different metabolic methods based on the most widely used tracer, i.e. D5-Phe stable isotope, in two experimental bed rest campaigns (FP7 PLANHAB and INTERREG PANGaA) in healthy volunteers. BR is a suitable model to investigate physiologic adaptation to inactivity.
MAIN RESUTLTS. FP7 PLANHAB. We applied the stable isotope infusion technique, to assess the effect of physical inactivity and/or hypoxic condition on whole body protein turnover as previously described in Biolo et al 2008. Chronic hypoxia has been associated with an overall reduction in protein synthesis and in total plasma and skeletal muscle protein content. During the PLANHAB study we investigated, through a crossover randomization, the net effects of 10 days normobaric hypoxia (4000 mt.), associated with either ambulatory conditions or BR, in 11 young (age 24±4 yr), healthy and normal weight male subjects maintained on eucaloric diets. Main results. Hypoxia in ambulatory conditions significantly decreased whole body protein turnover by reducing both protein synthesis (-8±2%) and protein degradation (-8±3%). Hypoxia during bed rest did not caused significant changes in protein metabolism.
INTERREG PANGaA. The skeletal muscle loss in aging is caused mainly by the “anabolic resistance” i.e. the inadequate increase in the rate of protein synthesis in response to nutritional-metabolic stimuli, including exercise, protein and amino acid intake as well as insulin and insulin-like growth factor stimulation. As a consequence, the net protein balance becomes negative leading to sarcopenia. The effects of ageing on the anabolic resistance induced by inactivity are poorly investigated. During the PANGeA study we had the opportunity to perform the second documented experimental BR in in healthy elderly volunteers and the first comparing aged with young subjects. To evaluate the anabolic resistance associated with ageing and inactivity, we enrolled 7 young (23±1yr) and 8 elderly (59±1yr) normal weight individuals, in a 14-d experimental BR protocol. We replaced our previous infusion method with a new, simpler, safer and quicker technique, by which tracers are given orally instead of parenterally, the all procedure is completed in two hours, instead of 6, and only two blood draws versus 7 are sufficient. Main results. At baseline parameters of anabolic sensitivity were comparable between young and elderly individuals. The anabolic resistance significantly increased after BR in both groups (bed-rest effect p<0.01), with a statistically significant bed-rest×group interaction (p=0.01). Anabolic resistance increased significantly in elderly (18.5%±7.3%) more than in young (5.2%±9.4%) subjects.
DISCUSSION. In the PLANHAB study, hypoxia in ambulatory conditions reduced by the same level both protein synthesis and catabolism, as measured by isotope infusions, suggesting an adaptive mechanism: the lower energy production and availability induced by hypoxia associated with ambulatory condition. These modifications could not have been revealed by the use of nitrogen balance method, showing the relevance of more sophisticated analysis. The direct evaluation of the muscle protein metabolism through an infusion of stable-labeled isotope tracer, considered the golden standard methodology, gave us, in the PLANHAB study, reliable results in the early protein metabolism changes during hypoxia and/or BR. This method however has the limit of being complex, onerous and invasive, therefore being unsuitable for clinical evaluation. In the PANGeA study we could confirm the presence of a reduced sensitivity to anabolic stimuli in the elderly population compared to the young men. The elderly subjects are therefore, more at risk to develop changes of protein metabolism induced by inactivity. The simpler, timesaving and less invasive method we have developed for the PANGeA study, on the other hand, could be applied to a wider ranges of experimental conditions and clinical settings.XXVII Ciclo198
Early lean mass sparing effect of high-protein diet with excess leucine during long-term bed rest in women
No full textMuscle inactivity leads to muscle atrophy. Leucine is known to inhibit protein degradation and to promote protein synthesis in skeletal muscle. We tested the ability of a high-protein diet enriched with branched-chain amino acids (BCAAs) to prevent muscle atrophy during long-term bed rest (BR). We determined body composition (using dual energy x-ray absorptiometry) at baseline and every 2-weeks during 60 days of BR in 16 healthy young women. Nitrogen (N) balance was assessed daily as the difference between N intake and N urinary excretion. The subjects were randomized into two groups: one received a conventional diet (1.1 ± 0.03 g protein/kg, 4.9 ± 0.3 g leucine per day) and the other a high protein, BCAA-enriched regimen (1.6 ± 0.03 g protein-amino acid/kg, 11.4 ± 0.6 g leucine per day). There were significant BR and BR × diet interaction effects on changes in lean body mass (LBM) and N balance throughout the experimental period (repeated measures ANCOVA). During the first 15 days of BR, lean mass decreased by 4.1 ± 0.9 and 2.4 ± 2.1% (p < 0.05) in the conventional and high protein-BCAA diet groups, respectively, while at the end of the 60-day BR, LBM decreased similarly in the two groups by 7.4 ± 0.7 and 6.8 ± 2.4%. During the first 15 days of BR, mean N balance was 2.5 times greater (p < 0.05) in subjects on the high protein-BCAA diet than in those on the conventional diet, while we did not find significant differences during the following time intervals. In conclusion, during 60 days of BR in females, a high protein-BCAA diet was associated with an early protein-LBM sparing effect, which ceased in the medium and long term
Metabolic consequences of anabolic steroids, insulin, and growth hormone abuse in recreational bodybuilders
Full text linkBackground Hormonal doping in recreational sports is a public-health concern. The World Anti-Doping Agency (WADA) promoted the creation of the Athlete Biological Passport, aiming to monitor athlete’s biological variables over time to facilitate indirect detection of doping. Detection tests for anabolic androgenic steroids (AAS) and growth hormone (GH) are available while insulin abuse cannot be revealed. We have determined in recreational bodybuilders the metabolic effects associated with different patterns of hormone abuse. All analyses were conducted using Statistical Package for Social Sciences (SPSS) 21.0 software (SPSS Chicago, IL). Results We have assessed plasma concentrations of selected metabolic markers and fatty acid content in erythrocyte membranes of 92 male bodybuilders and in 45 healthy controls. Hormonal abuse was identified by anonymous questionnaires. 43% (%) of recruited bodybuilders regularly abused hormones, i.e., anabolic androgenic steroids (95%) often associated with GH (30%) and/or insulin (38%). HDL-cholesterol was lower in insulin and/or GH abusers. Alanine (ALT) and aspartic (AST) transaminases were greater in hormone abusing bodybuilders than in non-doping bodybuilders and controls. Insulin doping was selectively associated with increased plasma ALT-to-AST ratio. In erythrocyte membranes, elongase activity (i.e., stearic-to-palmitic ratio) was lower in insulin and/or growth hormone doping, whereas increased Δ-9 desaturase activity (i.e., palmitoleic-to-palmitic ratio) was selectively associated with insulin doping. Conclusions In conclusion, our study demonstrates that insulin and GH abuse are characterized by multiple alterations of specific metabolic markers. Although further studies are needed to test whether longitudinal monitoring of selected metabolic marker such as muscle contraction time, HDL levels, ALT-AST ratio as well as the activities of selected enzymes (e.g. Δ-9 desaturase and elongase), could contribute to the detection of insulin and GH abuse in sport
Roasting intensity of naturally low-caffeine Laurina coffee modulates glucose metabolism and redox balance in humans
Full text linkObjective. Coffee consumption is negatively associated with risk of type 2 diabetes and cardiovascular mortality. Coffee roasting can greatly modify the quality-quantitative characteristics of bioactive compounds. We compared the effects of two different roasting intensities of the same naturally low-caffeine Arabica coffee variety (Laurina), on glucose and lipid metabolism as well as oxidative stress.
Research Methods & Procedures. We performed a double-blind, crossover intervention study. 14 healthy male volunteers consumed 4 cups/day of Light Roasted Coffee (LRC) and Dark Roasted Coffee (DRC) for one-week (intervention period 1 and 2 respectively). One-week washout, with total abstinence from coffee and other possible caffeine sources, preceded each interventions. Data were collected at the end of washout and intervention periods.
Results. Changes between washout and intervention periods in glucose concentrations at 2-h 12 post-OGTT, were significantly lower following DRC than LRC intake (-0.6±0.3 and 0.4±0.3 mmol/l, p<0.03). Changes in β-cell function, assessed as insulin secretion-sensitivity index-2 (ISSI2), were significantly greater following DRC than LRC (34.7±25.0 and -18.8±21.0,p=0.03). The initial (30 minutes) post-OGTT AUC of glucagon-like peptide-1 was 24±9% greater (p=0.03) after DRC than LRC. LRC or DRC did not affect insulin sensitivity. Changes from basal of reduced-to-oxidized glutathione ratio (GSH/GSSG) in erythrocytes were significantly greater after DRC than LRC (+1437±371 and -152±30, p<0.05). The omega-3 index in erythrocyte membranes was 16±4% greater (p<0.001) after DRC than LRC.
Conclusions. DRC consumption improved post-load glucose metabolism by increasing incretin and insulin secretions. DRC compared to LRC improved redox balance and increased omega-3 fatty acids. Thus, we suggest greater metabolic benefits related to DRC
Inverse relationship between "a body shape index" (ABSI) and fat-free mass in women and men: Insights into mechanisms of sarcopenic obesity.
No full textBACKGROUND & AIMS:
Sarcopenic obesity may be defined by a high fat to fat-free mass (FM/FFM) ratio. Skeletal muscle may be negatively influenced by the pro-inflammatory milieu associated with visceral fat, while the loading effect induced by a heavier body mass index (BMI) may enhance muscle anabolism. Recently, a new anthropometric measure based on waist circumference (A Body Shape Index, ABSI) was developed. In this study we have assessed the predictive power of ABSI on the FFM index (FFMI), a surrogate marker of lean mass.
METHODS:
Standard anthropometric parameters and ABSI as well as body composition data (fat and fat-free mass determined by bioelectrical impedance analysis) were assessed in 111 female and 89 male overweight/obese subjects, with no clinically significant co-morbidities. Groups with higher- or lower-ABSI were identified according to median values of this index.
RESULTS:
In women and men, ABSI did not correlate with BMI, while multiple linear regression indicated that BMI (β-coefficients: 0.62 and 0.77, respectively) and ABSI (β-coefficients: -0.26 and -0.22, respectively) independently predicted FFMI (multiple R: 0.72 and 0.83, respectively, P < 0.001). Men and women with lower-ABSI exhibited significantly greater FFMI than the higher-ABSI groups for comparable values of BMI. In men, ABSI was correlated positively with C-reactive protein (CRP) (R = 0.30; P < 0.05) and negatively with the reciprocal of insulin (R = 0.28; P < 0.05), an index of insulin sensitivity. FM/FFM ratio significantly (P < 0.01) correlated with CRP (R = 0.31) in women only.
CONCLUSIONS:
ABSI, a recently introduced marker of abdominal adiposity, may contribute to define the risk of sarcopenia in overweight/obese individuals
Baseline deficiency of the anti-inflammatory eicosapentaenoic acid in cell membranes worsens lean body mass wasting induced by inactivity
Full text linkBackground & aims: Arachidonic (AA) and eicosapentaenoic (EPA) polyunsaturated fatty acids can play respectively a pro- and an anti-inflammatory role. We hypothesized that, at the end of 5-week experimental bed rest, baseline AA/EPA in red blood cells (RBC) membranes, considered the result of dietary fat intake over the previous month, could influence lean body mass wasting in twenty-six healthy volunteers (age: 23.5 ± 0.5 years; body mass index: 22.9 ± 0.5 kg/m2).
Methods: We measured AA and EPA content in RBC membranes at baseline ambulatory conditions and at the end of the study protocol, to verify the PUFA concentrations stability. We assessed changes, between beginning and end of bed, in lean body mass (bioimpedance), insulin resistance (homeostasis model assessment), systemic inflammation (C-reactive protein) and oxidative stress (thiobarbituric acid reactive substances). Volunteers were divided in two groups according to the AA/EPA ratio median value (i.e. AA/EPA = 44): High AA/EPA group (60 ± 3; n = 13) and Low AA/EPA group (37 ± 1; n = 13).
Results: At baseline, all analyzed anthropometrical and biochemical indices were similar in the two groups. Bed rest induced a major decrease in lean body mass in High AA/EPA group (−5.2 ± 0.5%), when compared to Low AA/EPA group (−3.7 ± 0.5%; p = 0.03; ANOVA). Bed rest mediated-changes of insulin resistance, fat mass, systemic inflammation and oxidative stress, failed to show significant interaction with baseline AA/EPA (ANOVA). In pooled data, baseline AA/EPA ratio and percent lean body mass delta changes showed a significant inverse correlation (n = 26; R = −0.50; p < 0.01).
Conclusions: Results suggest that baseline AA/EPA, in RBC membranes, can independently predict lean body mass wasting in immobilized subjects during long term disuse
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