Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
51 result(s) for "Mazurak, Vera"
Sort by:
Sarcopenia in cirrhosis: from pathogenesis to interventions
Sarcopenia (severe muscle depletion) is a prevalent muscle abnormality in patients with cirrhosis that confers poor prognosis both pre- and post-liver transplantation. The pathogenesis of sarcopenia is multifactorial and results from an imbalance between protein synthesis and breakdown. Nutritional, metabolic, and biochemical abnormalities seen in chronic liver disease alter whole body protein homeostasis. Hyperammonemia, increased autophagy, proteasomal activity, lower protein synthesis, and impaired mitochondrial function play an important role in muscle depletion in cirrhosis. Factors including cellular energy status, availability of metabolic substrates (e.g., branched-chain amino acids), alterations in the endocrine system (insulin resistance, circulating levels of insulin, insulin-like growth factor-1, corticosteroids, and testosterone), cytokines, myostatin, and exercise are involved in regulating muscle mass. A favored atrophy of type II fast-twitch glycolytic fibers seems to occur in patients with cirrhosis and sarcopenia. Identification of muscle biological abnormalities and underlying mechanisms is required to plan clinical trials to reverse sarcopenia through modulation of specific mechanisms. Accordingly, a combination of nutritional, physical, and pharmacological interventions might be necessary to reverse sarcopenia in cirrhosis. Moderate exercise should be combined with appropriate energy and protein intake, in accordance with clinical guidelines. Interventions with branched chain amino acids, testosterone, carnitine, or ammonia-lowering therapies should be considered individually. Various factors such as dose, type, duration of supplementations, etiology of cirrhosis, amount of dietary protein intake, and compliance with supplementation and exercise should be the focus of future large randomized controlled trials investigating both prevention and treatment of sarcopenia in this patient population.
Subcutaneous adiposity is an independent predictor of mortality in cancer patients
Background: Prognostic significance of adiposity, at the time of cancer diagnosis, on survival is not clear. Body mass index (kg m −2 ) does not provide an appropriate assessment of body composition; therefore, the concept of the ‘obesity paradox’ needs to be investigated based on the prognostic significance of fat and muscle. Independent prognostic significance of adipose tissue in predicting mortality, importance of visceral and subcutaneous adiposity in the presence and absence of sarcopenia on survival, was investigated. Methods: Adiposity markers including total adipose index (TATI), visceral adipose tissue index (VATI) and subcutaneous adipose tissue index (SATI) were estimated for 1473 gastrointestinal and respiratory cancer patients and 273 metastatic renal cell carcinoma patients using computed tomography. Univariate and multivariate analysis to determine mortality hazard ratios (HR) were conducted using cox proportional hazard models. Results: Low SATI (SATI <50.0 cm 2  m −2 in males and <42.0 cm 2  m −2 in females) independently associated with increased mortality (HR: 1.26; 95% CI: 1.11–1.43; P <0.001) and shorter survival (13.1 months; 95% CI, 11.4–14.7) compared to patients with high SATI (19.3 months; 95% CI, 17.6–21.0; P <0.001). In the presence of sarcopenia, the longest survival was observed in patients with high subcutaneous adiposity. Conclusions: Subcutaneous adipose tissues appear to associate with reduction in mortality risk demonstrating the prognostic importance of fat distribution. The effect of sarcopenia on survival was more pronounced in patients with low subcutaneous adiposity.
Call for standardization in assessment and reporting of muscle and adipose change using computed tomography analysis in oncology: A scoping review
Investigators are increasingly measuring skeletal muscle (SM) and adipose tissue (AT) change during cancer treatment to understand impact on patient outcomes. Recent meta‐analyses have reported high heterogeneity in this literature, representing uncertainty in the resulting estimates. Using the setting of palliative‐intent chemotherapy as an exemplar, we aimed to systematically summarize the sources of variability among studies evaluating SM and AT change during cancer treatment and propose standards for future studies to enable reliable meta‐analysis. Studies that measured computed tomography‐defined SM and/or AT change in adult patients during palliative‐intent chemotherapy for solid tumours were included, with no date or geographical limiters. Of 2496 publications screened by abstract/title, 83 were reviewed in full text and 38 included for extraction, representing 34 unique cohorts across 8 tumour sites. The timing of baseline measurement was frequently defined as prior to treatment , while endpoint timing ranged from 6 weeks after treatment start to time of progression . Fewer than 50% specified the actual time interval between measurements. Measurement error was infrequently discussed (8/34). A single metric (cm 2 /m 2 , cm 2 or %) was used to describe SM change in 18/34 cohorts, while multiple metrics were presented for 10/34 and no descriptive metrics for 6/34. AT change metrics and sex‐specific reporting were available for 10/34 cohorts. Associations between SM loss and overall survival were evaluated in 24 publications, with classification of SM loss ranging from any loss to >14% loss over variable time intervals. Age and sex were the most common covariates, with disease response in 50% of models. Despite a wealth of data and effort, heterogeneity in study design, reporting and statistical analysis hinders evidence synthesis regarding the severity and outcomes of SM and AT change during cancer treatment. Proposed standards for study design include selection of homogenous cohorts, clear definition of baseline/endpoint timing and attention to measurement error. Standard reporting should include baseline SM and AT by sex, actual scan interval, SM and AT change using multiple metrics and visualization of the range of change observed. Reporting by sex would advance understanding of sexual dimorphism in SM and AT change. Evaluating the impact of tissue change on outcomes requires adjustment for relevant covariates and concurrent disease response. Adoption of these standards by researchers and publishers would alter the current paradigm to enable meta‐analysis of future studies and move the field towards meaningful application of SM and AT change to clinical care.
Pathways Contributing to Chemotherapy‐Induced Myotoxicity Are Attenuated by EPA + DHA in a Clinically Relevant Model of Colorectal Cancer
Background Skeletal muscle loss is a well‐recognized consequence of cancer, and chemotherapy exacerbates myotoxicity through multiple mechanisms. Retaining muscle mass improves tumour response to therapies and tolerance to chemotherapy; hence, interventions to mitigate myotoxicity warrant investigations. This study aimed to investigate the protective effects of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provided in the form of fish oil on chemotherapy‐induced myotoxicity using next‐generation RNA sequencing (NGS). Methods Fischer 344 rats were fed either a standard diet (STD) for the entire study or switched to a diet containing fish oil (2.3 g/100 g of diet) when chemotherapy (irinotecan + 5‐fluorouracil) was initiated. All rats received the Ward colon tumour and tumours were allowed to grow for 2 weeks. Comparisons were made between (1) tumour‐bearing rats on a standard diet (TUMOUR STD), (2) tumour‐bearing rats that received chemotherapy on a standard diet (CHEMO STD) and (3) tumour‐bearing rats that received chemotherapy on a fish oil diet (CHEMO FO). After two cycles of chemotherapy, NGS was performed on gastrocnemius muscle. Differential expression of genes was performed using DEseq2, with a fold‐change cut‐off ≥ 1.5 and p value < 0.05. Ingenuity pathway analysis (IPA) was used for functional annotation, canonical pathways and upstream regulators analysis. Results Transcriptomic analysis revealed distinct alterations in skeletal muscle gene expression profiles. In the CHEMO STD versus TUMOUR STD comparison, 272 genes showed differential expression. Of these, 55% were upregulated and 45% were downregulated. Two cycles of chemotherapy altered genes in the pathways of proliferation of muscle cells (p < 10−7), connective tissue disorder (p < 10−6), apoptosis (p < 10−3) and neurodevelopmental disorders (p < 10−3). In the CHEMO FO versus CHEMO STD comparison, 274 genes were differentially expressed (73% upregulated and 27% downregulated). Dietary fish oil exclusively altered immune‐related functions, notably downregulating several genes in the leukocyte extravasation pathway (−logp value 5.92, z score −2.83). Upstream regulatory molecules after chemotherapy were predicted to inhibit transcription factors involved in myogenic regeneration, while those fed a diet containing fish oil showed inhibition of inflammation‐related cytokines. Conclusion Chemotherapy negatively impacts processes involved in muscle homeostasis, including muscle cell proliferation and regeneration. The provision of fish oil primarily showed protective effects from pro‐inflammatory mediators by downregulating genes involved in the leukocyte extravasation pathway. Our findings provide novel insights into the molecular mechanisms underlying chemotherapy‐induced myotoxicity and the potential therapeutic benefits of dietary EPA + DHA to restore muscle homeostasis in cancer.
A 16-week randomized controlled trial of a fish oil and whey protein-derived supplement to improve physical performance in older adults losing autonomy—A pilot study
Low functional capacity may lead to the loss of independence and institutionalization of older adults. A nutritional intervention within a rehabilitation program may attenuate loss of muscle function in this understudied population. This pilot study assessed the feasibility for a larger RCT of a nutritional supplementation in older adults referred to an outpatient assessment and rehabilitation program. Participants were randomized to receive a supplement (EXP: 2g fish oil with 1500 IU vitamin D3 1x/d + 20-30g whey protein powder with 3g leucine 2x/d) or isocaloric placebo (CTR: corn oil + maltodextrin powder) for 16 weeks. Handgrip and knee extension strength (using dynamometry), physical performance tests and plasma phospholipid n-3 fatty acids (using GCMS) were evaluated at weeks 0, 8 and 16; and lean soft tissue mass (using DXA), at weeks 0 and 16. Over 2 years, 244 patients were screened, 46 were eligible (18.9%), 20 were randomized, 10 completed the study (6 CTR, 4 EXP). Median age was 87 y (77-94 y; 75% women) and gait speed was 0.69 m/s; 55% had low strength, and all performed under 420m on the 6-minute walk test, at baseline. Overall self-reported compliance to powder and oil was high (96% and 85%) but declined at 16 weeks for fish oil (55%). The EXP median protein intake surpassed the target 1.2-1.5 g/kg/d, without altering usual diet. Proportions of plasma phospholipid EPA and DHA increased significantly 3- and 1.5-fold respectively, at week 8 in EXP, with no change in CTR. Participants were able to complete most assessments with sustained guidance. Because of low eligibility, the pilot study was interrupted and deemed non-feasible; adherence to rigorous study assessments and to supplements was adequate except for long-term fish oil. The non-amended protocol may be applied to populations with greater functional capacity. ClinicalTrials.gov NCT04454359.
Determination of the Relative Efficacy of Eicosapentaenoic Acid and Docosahexaenoic Acid for Anti-Cancer Effects in Human Breast Cancer Models
Epidemiological studies have associated high fish oil consumption with decreased risk of breast cancer (BC). n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish and fish oils exert anti-cancer effects. However, few studies have examined the relative efficacy of EPA and DHA alone and in mixtures on BC subtypes. This was the objective of the present review, as this research is a necessity for the translation of findings to human health and disease. The literature suggests that DHA has a greater anti-cancer effect in triple negative BC (TNBC). In estrogen positive (ER+) BC, DHA has a greater effect on cell viability, while both fatty acids have similar effects on apoptosis and proliferation. These effects are associated with preferential uptake of DHA into TNBC lipid rafts and EPA in ER+ BC. EPA:DHA mixtures have anti-cancer activity; however, the ratio of EPA:DHA does not predict the relative incorporation of these two fatty acids into membrane lipids as EPA appears to be preferentially incorporated. In summary, DHA and EPA should be considered separately in the context of BC prevention. The elucidation of optimal EPA:DHA ratios will be important for designing targeted n-3 LCPUFA treatments.
Potential Biomarkers of Fat Loss as a Feature of Cancer Cachexia
Fat loss is associated with shorter survival and reduced quality of life in cancer patients. Effective intervention for fat loss in cachexia requires identification of the condition using prognostic biomarkers for early detection and prevention of further depletion. No biomarkers of fat mass alterations have been defined for application to the neoplastic state. Several inflammatory cytokines have been implicated in mediating fat loss associated with cachexia; however, plasma levels may not relate to adipose atrophy. Zinc-α2-glycoprotein may be a local catabolic mediator within adipose tissue rather than serving as a plasma biomarker of fat loss. Plasma glycerol and leptin associate with adipose tissue atrophy and mass, respectively; however, no study has evaluated their potential as a prognostic biomarker of cachexia-associated fat loss. This review confirms the need for further studies to identify valid prognostic biomarkers to identify loss of fat based on changes in plasma levels of biomarkers.
N-3 Polyunsaturated Fatty Acids: Relationship to Inflammation in Healthy Adults and Adults Exhibiting Features of Metabolic Syndrome
Individuals with metabolic syndrome (MetS) have a higher risk of type 2 diabetes and cardiovascular disease, therefore, research has been directed at reducing various components that contribute to MetS and associated metabolic impairments, including chronic low-grade inflammation. Epidemiological, human, animal and cell culture studies provide evidence that dietary n-3 polyunsaturated fatty acids (n-3 PUFA), including alpha-linolenic acid (18:3n-3, ALA), eicosapentaenoic acid (20:5n-3, EPA) and/or docosahexaenoic acid (22:6n-3, DHA) may improve some of the components associated with MetS. The current review will discuss recent evidence from human observational and intervention studies that focused on the effects of ALA, EPA or DHA on inflammatory markers in healthy adults and those with one or more features of MetS. Observational studies in healthy adults support the recommendation that a diet rich in n-3 fatty acids may play a role in preventing and reducing inflammation, whereas intervention studies in healthy adults have yielded inconsistent results. The majority of intervention studies in adults with features of MetS have reported a benefit for some inflammatory measures; however, other studies using high n-3 fatty acid doses and long supplementation periods have reported no effect. Overall, the data reviewed herein support recommendations for regular fatty fish consumption and point toward health benefits in terms of lowering inflammation in adults with one or more features of MetS.
Fish oil mitigates myosteatosis and improves chemotherapy efficacy in a preclinical model of colon cancer
This study aimed to assess whether feeding a diet containing fish oil was efficacious in reducing tumor- and subsequent chemotherapy-associated myosteatosis, and improving tumor response to treatment. Female Fischer 344 rats were fed either a control diet for the entire study (control), or switched to a diet containing fish oil (2.0 g /100 g of diet) one week prior to tumor implantation (long term fish oil) or at the start of chemotherapy (adjuvant fish oil). Chemotherapy (irinotecan plus 5-fluorouracil) was initiated 2 weeks after tumor implantation (cycle-1) and 1 week thereafter (cycle-2). Reference animals received no tumor or treatment and only consumed the control diet. All skeletal muscle measures were conducted in the gastrocnemius. To assess myosteatosis, lipids were assessed histologically by Oil Red O staining and total triglyceride content was quantified by gas chromatography. Expression of adipogenic transcription factors were assessed at the mRNA level by real-time RT-PCR. Feeding a diet containing fish oil significantly reduced tumor- and subsequent chemotherapy-associated increases in skeletal muscle neutral lipid (p<0.001) and total triglyceride content (p<0.03), and expression of adipogenic transcription factors (p<0.01) compared with control diet fed animals. The adjuvant fish oil diet was as effective as the long term fish oil diet in mitigating chemotherapy-associated skeletal muscle fat content, and in reducing tumor volume during chemotherapy compared with control fed animals (p<0.01). Long term and adjuvant fish oil diets are equally efficacious in reducing chemotherapy-associated myosteatosis that may be occurring by reducing expression of transcription factors involved in adipogenesis/lipogenesis, and improving tumor-response to chemotherapy in a neoplastic model.
Myosteatosis in Cirrhosis: A Review of Diagnosis, Pathophysiological Mechanisms and Potential Interventions
Myosteatosis, or pathological excess fat accumulation in muscle, has been widely defined as a lower mean skeletal muscle radiodensity on computed tomography (CT). It is reported in more than half of patients with cirrhosis, and preliminary studies have shown a possible association with reduced survival and increased risk of portal hypertension complications. Despite the clinical implications in cirrhosis, a standardized definition for myosteatosis has not yet been established. Currently, little data exist on the mechanisms by which excess lipid accumulates within the muscle in individuals with cirrhosis. Hyperammonemia may play an important role in the pathophysiology of myosteatosis in this setting. Insulin resistance, impaired mitochondrial oxidative phosphorylation, diminished lipid oxidation in muscle and age-related differentiation of muscle stem cells into adipocytes have been also been suggested as potential mechanisms contributing to myosteatosis. The metabolic consequence of ammonia-lowering treatments and omega-3 polyunsaturated fatty acids in reversing myosteatosis in cirrhosis remains uncertain. Factors including the population of interest, design and sample size, single/combined treatment, dosing and duration of treatment are important considerations for future trials aiming to prevent or treat myosteatosis in individuals with cirrhosis.