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Orthopaedic Journal of Sports Medicine Mar 2020Low-load blood flow restriction (BFR) training has attracted attention as a potentially effective method of perioperative clinical rehabilitation for patients undergoing... (Review)
Review
BACKGROUND
Low-load blood flow restriction (BFR) training has attracted attention as a potentially effective method of perioperative clinical rehabilitation for patients undergoing orthopaedic procedures.
PURPOSE
To (1) compare the effectiveness of low-load BFR training in conjunction with a standard rehabilitation protocol, pre- and postoperatively, and non-BFR interventions in patients undergoing anterior cruciate ligament reconstruction (ACLR) and (2) evaluate protocols for implementing BFR perioperatively for patients undergoing ACLR.
STUDY DESIGN
Systematic review; Level of evidence, 2.
METHODS
A systematic review of the 3 medical literature databases was conducted to identify all level 1 and 2 clinical trials published since 1990 on BFR in patients undergoing ACLR. Patient demographics from included studies were pooled. Outcome data were documented, including muscle strength and size, and perceived pain and exertion. A descriptive analysis of outcomes from BFR and non-BFR interventions was performed.
RESULTS
A total of 6 studies (154 patients; 66.2% male; mean ± SD age, 24.2 ± 3.68 years) were included. Of these, 2 studies examined low-load BFR as a preoperative intervention, 1 of which observed a significant increase in muscle isometric endurance ( = .014), surface electromyography of the vastus medialis ( < .001), and muscle blood flow to the vastus lateralis at final follow-up ( < .001) as compared with patients undergoing sham BFR. Four studies investigated low-load BFR as a postoperative intervention, and they observed significant benefits in muscle hypertrophy, as measured by cross-sectional area; strength, as measured by extensor torque; and subjective outcomes, as measured by subjective knee pain during session, over traditional low-load resistance training (all < .05). BFR occlusion periods ranged from 3 to 5 minutes, with rest periods ranging from 45 seconds to 3 minutes.
CONCLUSION
This systematic review found evidence on the topic of BFR rehabilitation after ACLR to be sparse and heterogeneous likely because of the relatively recent onset of its popularity. While a few authors have demonstrated the potential strength and hypertrophy benefits of perioperative BFR, future investigations with standardized outcomes, long-term follow-up, and more robust sample sizes are required to draw more definitive conclusions.
PubMed: 32232065
DOI: 10.1177/2325967120906822 -
Medicine and Science in Sports and... Jul 2018The myonuclear domain theory postulates that myonuclei are added to muscle fibers when increases in fiber cross-sectional area (i.e., hypertrophy) are ≥26%. However,... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
The myonuclear domain theory postulates that myonuclei are added to muscle fibers when increases in fiber cross-sectional area (i.e., hypertrophy) are ≥26%. However, recent studies have reported increased myonuclear content with lower levels (e.g., 12%) of muscle fiber hypertrophy.
PURPOSE
This study aimed to determine whether a muscle fiber hypertrophy "threshold" is required to drive the addition of new myonuclei to existing muscle fibers.
METHODS
Studies of resistance training endurance training with or without nutrient (i.e., protein) supplementation and steroid administration with measures of muscle fiber hypertrophy and myonuclei number as primary or secondary outcomes were considered. Twenty-seven studies incorporating 62 treatment groups and 903 subjects fulfilled the inclusion criteria and were included in the analyses.
RESULTS
Muscle fiber hypertrophy of ≤10% induces increases in myonuclear content, although a significantly higher number of myonuclei are observed when muscle hypertrophy is ~22%. Additional analyses showed that age, sex, and muscle fiber type do not influence muscle fiber hypertrophy or myonuclei addition.
CONCLUSIONS
Although a more consistent myonuclei addition occurs when muscle fiber hypertrophy is >22%, our results challenge the concept of a muscle hypertrophy threshold as significant myonuclei addition occurs with lower muscle hypertrophy (i.e., <10%).
Topics: Cell Nucleus; Humans; Hypertrophy; Muscle Fibers, Skeletal; Muscle, Skeletal; Resistance Training; Satellite Cells, Skeletal Muscle
PubMed: 29509639
DOI: 10.1249/MSS.0000000000001593 -
Journal of Human Hypertension Mar 2018Cognitive impairment is common in patients with hypertension. Left ventricular hypertrophy (LVH) is recognised as a marker of hypertension-related organ damage and is a...
Cognitive impairment is common in patients with hypertension. Left ventricular hypertrophy (LVH) is recognised as a marker of hypertension-related organ damage and is a strong predictor of coronary artery disease, heart failure and stroke. There is evidence that LVH is independently associated with cognitive impairment, even after adjustment for the presence of hypertension. We conducted a systematic review that examined cognitive impairment in adults with LVH. Independent searches were performed in Ovid MEDLINE, Ovid psycInfo and PubMed with the terms left ventricular hypertrophy and cognition. Seventy-three studies were identified when both searches were combined. After limiting the search to studies that were: (1) reported in English; (2) conducted in humans; (3) in adults aged 50 years and older; and (4) investigated the relationship between LVH and cognitive performance, nine papers were included in this systematic review. The majority of studies found an association between LVH and cognitive performance. Inspection of results indicated that individuals with LVH exhibited a lower performance in cognitive tests, when compared to individuals without LVH. Memory and executive functions were the cognitive domains that showed a specific vulnerability to the presence of LVH. A possible mechanism for the relationship between LVH and cognition is the presence of cerebral white matter damage. White matter lesions occur frequently in patients with LVH and may contribute to cognitive dysfunction. Together, the results of this review suggest that memory impairment and executive dysfunction are the cognitive domains that showed a particular association with the presence of LVH.
Topics: Cognition; Cognitive Dysfunction; Humans; Hypertrophy, Left Ventricular
PubMed: 29330420
DOI: 10.1038/s41371-017-0023-0 -
Journal of Cachexia, Sarcopenia and... Jun 2024Proliferating cancer cells shift their metabolism towards glycolysis, even in the presence of oxygen, to especially generate glycolytic intermediates as substrates for...
BACKGROUND
Proliferating cancer cells shift their metabolism towards glycolysis, even in the presence of oxygen, to especially generate glycolytic intermediates as substrates for anabolic reactions. We hypothesize that a similar metabolic remodelling occurs during skeletal muscle hypertrophy.
METHODS
We used mass spectrometry in hypertrophying C2C12 myotubes in vitro and plantaris mouse muscle in vivo and assessed metabolomic changes and the incorporation of the [U-C]glucose tracer. We performed enzyme inhibition of the key serine synthesis pathway enzyme phosphoglycerate dehydrogenase (Phgdh) for further mechanistic analysis and conducted a systematic review to align any changes in metabolomics during muscle growth with published findings. Finally, the UK Biobank was used to link the findings to population level.
RESULTS
The metabolomics analysis in myotubes revealed insulin-like growth factor-1 (IGF-1)-induced altered metabolite concentrations in anabolic pathways such as pentose phosphate (ribose-5-phosphate/ribulose-5-phosphate: +40%; P = 0.01) and serine synthesis pathway (serine: -36.8%; P = 0.009). Like the hypertrophy stimulation with IGF-1 in myotubes in vitro, the concentration of the dipeptide l-carnosine was decreased by 26.6% (P = 0.001) during skeletal muscle growth in vivo. However, phosphorylated sugar (glucose-6-phosphate, fructose-6-phosphate or glucose-1-phosphate) decreased by 32.2% (P = 0.004) in the overloaded muscle in vivo while increasing in the IGF-1-stimulated myotubes in vitro. The systematic review revealed that 10 metabolites linked to muscle hypertrophy were directly associated with glycolysis and its interconnected anabolic pathways. We demonstrated that labelled carbon from [U-C]glucose is increasingly incorporated by ~13% (P = 0.001) into the non-essential amino acids in hypertrophying myotubes, which is accompanied by an increased depletion of media serine (P = 0.006). The inhibition of Phgdh suppressed muscle protein synthesis in growing myotubes by 58.1% (P < 0.001), highlighting the importance of the serine synthesis pathway for maintaining muscle size. Utilizing data from the UK Biobank (n = 450 243), we then discerned genetic variations linked to the serine synthesis pathway (PHGDH and PSPH) and to its downstream enzyme (SHMT1), revealing their association with appendicular lean mass in humans (P < 5.0e-8).
CONCLUSIONS
Understanding the mechanisms that regulate skeletal muscle mass will help in developing effective treatments for muscle weakness. Our results provide evidence for the metabolic rewiring of glycolytic intermediates into anabolic pathways during muscle growth, such as in serine synthesis.
Topics: Glucose; Muscle, Skeletal; Animals; Mice; Humans; Hypertrophy; Muscle Fibers, Skeletal; Insulin-Like Growth Factor I; Metabolomics
PubMed: 38742477
DOI: 10.1002/jcsm.13468 -
Journal of Stroke May 2020Left ventricular hypertrophy (LVH) is associated with the risk of stroke and dementia independently of other vascular risk factors, but its association with cerebral...
BACKGROUND AND PURPOSE
Left ventricular hypertrophy (LVH) is associated with the risk of stroke and dementia independently of other vascular risk factors, but its association with cerebral small vessel disease (CSVD) remains unknown. Here, we employed a systematic review and meta-analysis to address this gap.
METHODS
Following the MOOSE guidelines (PROSPERO protocol: CRD42018110305), we systematically searched the literature for studies exploring the association between LVH or left ventricular (LV) mass, with neuroimaging markers of CSVD (lacunes, white matter hyperintensities [WMHs], cerebral microbleeds [CMBs]). We evaluated risk of bias and pooled association estimates with random-effects meta-analyses.
RESULTS
We identified 31 studies (n=25,562) meeting our eligibility criteria. In meta-analysis, LVH was associated with lacunes and extensive WMHs in studies of the general population (odds ratio [OR]lacunes, 1.49; 95% confidence interval [CI], 1.12 to 2.00) (ORWMH, 1.73; 95% CI, 1.38 to 2.17) and studies in highrisk populations (ORlacunes: 2.39; 95% CI, 1.32 to 4.32) (ORWMH, 2.01; 95% CI, 1.45 to 2.80). The.
RESULTS
remained stable in general population studies adjusting for hypertension and other vascular risk factors, as well as in sub-analyses by LVH assessment method (echocardiography/electrocardiogram), study design (cross-sectional/cohort), and study quality. Across LV morphology patterns, we found gradually increasing ORs for concentric remodelling, eccentric hypertrophy, and concentric hypertrophy, as compared to normal LV geometry. LVH was further associated with CMBs in high-risk population studies.
CONCLUSION
s LVH is associated with neuroimaging markers of CSVD independently of hypertension and other vascular risk factors. Our findings suggest LVH as a novel risk factor for CSVD and highlight the link between subclinical heart and brain damage.
PubMed: 32635685
DOI: 10.5853/jos.2019.03335 -
Sports Medicine (Auckland, N.Z.) Feb 2024Many sports require maximal strength and endurance performance. Concurrent strength and endurance training can lead to suboptimal training adaptations. However, how... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Many sports require maximal strength and endurance performance. Concurrent strength and endurance training can lead to suboptimal training adaptations. However, how adaptations differ between males and females is currently unknown. Additionally, current training status may affect training adaptations.
OBJECTIVE
We aimed to assess sex-specific differences in adaptations in strength, power, muscle hypertrophy, and maximal oxygen consumption ( O) to concurrent strength and endurance training in healthy adults. Second, we investigated how training adaptations are influenced by strength and endurance training status.
METHODS
A systematic review and meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and a Cochrane risk of bias was evaluated. ISI Web of science, PubMed/MEDLINE, and SPORTDiscus databases were searched using the following inclusion criteria: healthy adults aged 18-50 years, intervention period of ≥ 4 weeks, and outcome measures were defined as upper- and lower-body strength, power, hypertrophy, and/or O. A meta-analysis was performed using a random-effects model and reported in standardized mean differences.
RESULTS
In total, 59 studies with 1346 participants were included. Concurrent training showed blunted lower-body strength adaptations in males, but not in females (male: - 0.43, 95% confidence interval [- 0.64 to - 0.22], female: 0.08 [- 0.34 to 0.49], group difference: P = 0.03). No sex differences were observed for changes in upper-body strength (P = 0.67), power (P = 0.37), or O (P = 0.13). Data on muscle hypertrophy were insufficient to draw any conclusions. For training status, untrained but not trained or highly trained endurance athletes displayed lower O gains with concurrent training (P = 0.04). For other outcomes, no differences were found between untrained and trained individuals, both for strength and endurance training status.
CONCLUSIONS
Concurrent training results in small interference for lower-body strength adaptations in males, but not in females. Untrained, but not trained or highly trained endurance athletes demonstrated impaired improvements in O following concurrent training. More studies on females and highly strength-trained and endurance-trained athletes are warranted.
CLINICAL TRIAL REGISTRATION
PROSPERO: CRD42022370894.
Topics: Adult; Humans; Male; Female; Endurance Training; Physical Endurance; Athletes; Sports; Hypertrophy; Muscle Strength; Resistance Training
PubMed: 37847373
DOI: 10.1007/s40279-023-01943-9 -
Scientific Reports Mar 2023A systematic review and meta-analysis was conducted to determine the effects of resistance training under hypoxic conditions (RTH) on muscle hypertrophy and strength... (Meta-Analysis)
Meta-Analysis
A systematic review and meta-analysis was conducted to determine the effects of resistance training under hypoxic conditions (RTH) on muscle hypertrophy and strength development. Searches of PubMed-Medline, Web of Science, Sport Discus and the Cochrane Library were conducted comparing the effect of RTH versus normoxia (RTN) on muscle hypertrophy (cross sectional area (CSA), lean mass and muscle thickness) and strength development [1-repetition maximum (1RM)]. An overall meta-analysis and subanalyses of training load (low, moderate or high), inter-set rest interval (short, moderate or long) and severity of hypoxia (moderate or high) were conducted to explore the effects on RTH outcomes. Seventeen studies met inclusion criteria. The overall analyses showed similar improvements in CSA (SMD [CIs] = 0.17 [- 0.07; 0.42]) and 1RM (SMD = 0.13 [0.0; 0.27]) between RTH and RTN. Subanalyses indicated a medium effect on CSA for longer inter-set rest intervals and a small effect for moderate hypoxia and moderate loads favoring RTH. Moreover, a moderate effect for longer inter-set rest intervals and a trivial effect for severe hypoxia and moderate loads favoring RTH was found on 1RM. Evidence suggests that RTH employed with moderate loads (60-80% 1RM) and longer inter-set rest intervals (≥ 120 s) enhances muscle hypertrophy and strength compared to normoxia. The use of moderate hypoxia (14.3-16% FiO) seems to be somewhat beneficial to hypertrophy but not strength. Further research is required with greater standardization of protocols to draw stronger conclusions on the topic.
Topics: Humans; Animals; Resistance Training; Gastropoda; Hypertrophy; Hypoxia; Muscles
PubMed: 36871095
DOI: 10.1038/s41598-023-30808-4 -
Hypertension (Dallas, Tex. : 1979) Nov 2023Masked hypertension (MH) occurs when office blood pressure is normal, but hypertension is confirmed using out-of-office blood pressure measures. Hypertension is a risk... (Meta-Analysis)
Meta-Analysis Review
Masked hypertension (MH) occurs when office blood pressure is normal, but hypertension is confirmed using out-of-office blood pressure measures. Hypertension is a risk factor for subclinical cardiovascular outcomes, including left ventricular hypertrophy, increased left ventricular mass index, carotid intima media thickness, and pulse wave velocity. However, the risk factors for ambulatory blood pressure monitoring defined MH and its association with subclinical cardiovascular outcomes are unclear. A systematic literature search on 9 databases included English publications from 1974 to 2023. Pediatric MH prevalence was stratified by disease comorbidities and compared with the general pediatric population. We also compared the prevalence of left ventricular hypertrophy, and mean differences in left ventricular mass index, carotid intima media thickness, and pulse wave velocity between MH versus normotensive pediatric patients. Of 2199 screened studies, 136 studies (n=28 612; ages 4-25 years) were included. The prevalence of MH in the general pediatric population was 10.4% (95% CI, 8.00-12.80). Compared with the general pediatric population, the risk ratio (RR) of MH was significantly greater in children with coarctation of the aorta (RR, 1.91), solid-organ or stem-cell transplant (RR, 2.34), chronic kidney disease (RR, 2.44), and sickle cell disease (RR, 1.33). MH patients had increased risk of subclinical cardiovascular outcomes compared with normotensive patients, including higher left ventricular mass index (mean difference, 3.86 g/m [95% CI, 2.51-5.22]), left ventricular hypertrophy (odds ratio, 2.44 [95% CI, 1.50-3.96]), and higher pulse wave velocity (mean difference, 0.30 m/s [95% CI, 0.14-0.45]). The prevalence of MH is significantly elevated among children with various comorbidities. Children with MH have evidence of subclinical cardiovascular outcomes, which increases their risk of long-term cardiovascular disease.
Topics: Humans; Child; Masked Hypertension; Hypertrophy, Left Ventricular; Blood Pressure Monitoring, Ambulatory; Carotid Intima-Media Thickness; Prevalence; Pulse Wave Analysis; Hypertension; Blood Pressure
PubMed: 37737026
DOI: 10.1161/HYPERTENSIONAHA.123.20967 -
Epilepsia Open Mar 2023Epilepsy is associated with an increased risk of cardiovascular disease and mortality. Whether cardiac structure and function are altered in epilepsy remains unclear. To... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Epilepsy is associated with an increased risk of cardiovascular disease and mortality. Whether cardiac structure and function are altered in epilepsy remains unclear. To address this, we conducted a systematic review and meta-analysis of studies evaluating cardiac structure and function in patients with epilepsy.
METHODS
We searched the electronic databases MEDLINE, PubMed, COCHRANE, and Web of Science from inception to 31 December 2021. Primary outcomes of interest included left ventricular ejection fraction (LVEF) for studies reporting echocardiogram findings and cardiac weight and fibrosis for postmortem investigations. Study quality was assessed using the National Heart, Lung, and Blood Institute (NHLBI) assessment tools.
RESULTS
Among the 10 case-control studies with epilepsy patients (n = 515) and healthy controls (n = 445), LVEF was significantly decreased in epilepsy group compared with controls (MD: -1.80; 95% confidence interval [CI]: -3.56 to -0.04; P = 0.045), whereas A-wave velocity (MD: 4.73; 95% CI: 1.87-7.60; P = 0.001), E/e' ratio (MD: 0.39; 95% CI: 0.06-0.71; P = 0.019), and isovolumic relaxation time (MD: 10.18; 95% CI: 2.05-18.32; P = 0.014) were increased in epilepsy, compared with controls. A pooled analysis was performed in sudden unexpected death in epilepsy (SUDEP) cases with autopsy data (n = 714). Among SUDEP cases, the prevalence of cardiac hypertrophy was 16% (95% CI: 9%-23%); cardiac fibrosis was 20% (95% CI: 15%-26%). We found no marked differences in cardiac hypertrophy, heart weight, or cardiac fibrosis between SUDEP cases and epilepsy controls.
SIGNIFICANCE
Our findings suggest that epilepsy is associated with altered diastolic and systolic echocardiogram parameters compared with healthy controls. Notably, SUDEP does not appear to be associated with a higher incidence of structural cardiac abnormalities, compared with non-SUDEP epilepsy controls. Longitudinal studies are needed to understand the prognostic significance of such changes. Echocardiography may be a useful noninvasive diagnostic test in epilepsy population.
Topics: Humans; Stroke Volume; Risk Factors; Ventricular Function, Left; Epilepsy; Death, Sudden; Sudden Unexpected Death in Epilepsy; Fibrosis; Cardiomegaly
PubMed: 36648338
DOI: 10.1002/epi4.12692 -
Clinical Hypertension Sep 2023In patients with end-stage renal disease (ESRD) undergoing dialysis, hypertension is common but often inadequately controlled. The prevalence of hypertension varies... (Review)
Review
In patients with end-stage renal disease (ESRD) undergoing dialysis, hypertension is common but often inadequately controlled. The prevalence of hypertension varies widely among studies because of differences in the definition of hypertension and the methods of used to measure blood pressure (BP), i.e., peri-dialysis or ambulatory BP monitoring (ABPM). Recently, ABPM has become the gold standard for diagnosing hypertension in dialysis patients. Home BP monitoring can also be a good alternative to ABPM, emphasizing BP measurement outside the hemodialysis (HD) unit. One thing for sure is pre- and post-dialysis BP measurements should not be used alone to diagnose and manage hypertension in dialysis patients. The exact target of BP and the relationship between BP and all-cause mortality or cause-specific mortality are unclear in this population. Many observational studies with HD cohorts have almost universally reported a U-shaped or even an L-shaped association between BP and all-cause mortality, but most of these data are based on the BP measured in HD units. Some data with ABPM have shown a linear association between BP and mortality even in HD patients, similar to the general population. Supporting this, the results of meta-analysis have shown a clear benefit of BP reduction in HD patients. Therefore, further research is needed to determine the optimal target BP in the dialysis population, and for now, an individualized approach is appropriate, with particular emphasis on avoiding excessively low BP. Maintaining euvolemia is of paramount importance for BP control in dialysis patients. Patient heterogeneity and the lack of comparative evidence preclude the recommendation of one class of medication over another for all patients. Recently, however, β-blockers could be considered as a first-line therapy in dialysis patients, as they can reduce sympathetic overactivity and left ventricular hypertrophy, which contribute to the high incidence of arrhythmias and sudden cardiac death. Several studies with mineralocorticoid receptor antagonists have also reported promising results in reducing mortality in dialysis patients. However, safety issues such as hyperkalemia or hypotension should be further evaluated before their use.
PubMed: 37653470
DOI: 10.1186/s40885-023-00240-x