New genetic signatures associated with cancer cachexia as defined by low skeletal muscle index and weight loss

Immunoregulation in cancer-associated cachexia

BACKGROUND

Cancer-associated cachexia is a multi-organ disorder associated with progressive weight loss due to a variable combination of anorexia, systemic inflammation and excessive energy wasting. Considering the importance of immunoregulation in cachexia, it still lacks a complete understanding of the immunological mechanisms in cachectic progression.

AIM OF REVIEW

Our aim here is to describe the complex immunoregulatory system in cachexia. We summarize the effects and translational potential of the immune system on the development of cancer-associated cachexia and we attempt to conclude with thoughts on precise and integrated therapeutic strategies under the complex immunological context of cachexia.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three main key concepts. First, we highlight the inflammatory factors and additional mediators that have been identified to modulate this syndrome. Second, we decipher the potential role of immune checkpoints in tissue wasting. Third, we discuss the multilayered insights in cachexia through the immunometabolic axis, immune-gut axis and immune-nerve axis.

Longitudinal Muscle Biopsies Reveal Inter- and Intra-Subject Variability in Cancer Cachexia: Paving the Way for Biopsy-Guided Tailored Treatment

In the rapidly evolving landscape of cancer cachexia research, the development and refinement of diagnostic and predictive biomarkers constitute an ongoing challenge. This study aims to introduce longitudinal muscle biopsies as a potential framework for disease monitoring and treatment. The initial feasibility and safety assessment was performed for healthy mice and rats that received two consecutive muscle biopsies. The assessment was performed by utilizing three different tools. Subsequently, the protocol was also applied in leiomyosarcoma tumor-bearing rats. Longitudinal muscle biopsies proved to be a safe and feasible technique, especially in rat models. The application of this protocol to tumor-bearing rats further affirmed its tolerability and feasibility, while microscopic evaluation of the biopsies demonstrated varying levels of muscle atrophy with or without leukocyte infiltration. In this tumor model, sequential muscle biopsies confirmed the variability of the cancer cachexia evolution among subjects and at different time-points. Despite the abundance of promising cancer cachexia data during the past decade, the full potential of muscle biopsies is not being leveraged. Sequential muscle biopsies throughout the disease course represent a feasible and safe tool that can be utilized to guide precision treatment and monitor the response in cancer cachexia research.

Association of the rs3917647 polymorphism of the SELP gene with malnutrition in gastric cancer

BACKGROUND

Malnutrition and cachexia are common syndromes in patients with gastric cancer (GC) and are associated with poor quality of life and poor disease prognosis. However, there is still a lack of molecular factors that can predict malnutrition or cachexia in cancer. Studies have shown that among the potential contributors to the development of cancer cachexia, the level of the inflammatory response to P-selectin is regulated by single nucleotide polymorphisms (SNPs) located in the promoter region of the SELP gene. The aim of this study was to evaluate the association between the single nucleotide polymorphism (SNP)-2028 A/G of the SELP gene and malnutrition in patients receiving chemotherapy for gastric cancer (GC).

METHODS

The study group consisted of 220 GC patients treated with chemotherapy at Jinhua Municipal Central Hospital. DNA was extracted from peripheral leukocytes of whole blood samples using an animal DNA extraction kit. DNA was amplified using a 1.1 × T3 Super PCR mix, and loci corresponding to the peaks were genotyped using SNP1 software.

RESULTS

Patients carrying the A allele had a reduced risk of developing malnutrition compared to patients with the GG genotype (P < 0.001; OR = 3.411; 95% CI = 1.785-6.516). In addition, multivariate analysis indicated that the AA genotype significantly (more than 16-fold) reduced the risk of developing malnutrition (P < 0.001; OR = 0.062; 95% CI = 0.015-0.255).

CONCLUSION

SELP -2028A/G SNP may be a useful marker for assessing the risk of malnutrition in GC patients.

Role of growth differentiation factor 15 in cancer cachexia (Review)

Growth differentiation factor 15 (GDF15), a member of the transforming growth factor-β family, is a stress-induced cytokine. Under normal circumstances, the expression of GDF15 is low in most tissues. It is highly expressed during tissue injury, inflammation, oxidative stress and cancer. GDF15 has been established as a biomarker in patients with cancer, and is associated with cancer cachexia (CC) and poor survival. CC is a multifactorial metabolic disorder characterized by severe muscle and adipose tissue atrophy, loss of appetite, anemia and bone loss. Cachexia leads to reductions in quality of life and tolerance to anticancer therapy, and results in a poor prognosis in cancer patients. Dysregulated GDF15 levels have been discovered in patients with CC and animal models, where they have been found to be involved in anorexia and weight loss. Although studies have suggested that GDF15 mediates anorexia and weight loss in CC through its neuroreceptor, glial cell-lineage neurotrophic factor family receptor α-like, the effects of GDF15 on CC and the potential regulatory mechanisms require further elucidation. In the present review, the characteristics of GDF15 and its roles and molecular mechanisms in CC are elaborated. The targeting of GDF15 as a potential therapeutic strategy for CC is also discussed.

The roles of P-selectin in cancer cachexia

P-selectin, a cell adhesion molecule of the selectin family, is expressed on the surface of activated endothelial cells (ECs) and platelets. Binding of P-selectin to P-selectin glycoprotein ligand-1 (PSGL-1) supports the leukocytes capture and rolling on stimulated ECs and increases the aggregation of leukocytes and activated platelets. Cancer cachexia is a systemic inflammation disorder characterized by metabolic disturbances, reduced body weight, loss of appetite, fat depletion, and progressive muscle atrophy. Cachexia status is associated with increased pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), which activates ECs to release P-selectin. Single-nucleotide polymorphisms (SNPs) loci of P-selectin encoding gene SELP are associated with higher level of plasma P-selectin and increase the susceptibility to cachexia in cancer patients. Elevated P-selectin expression has been observed in the hypothalamus, liver, and gastrocnemius muscle in animal models with cancer cachexia. Increased P-selectin may cause excessive inflammatory processes, muscle atrophy, and blood hypercoagulation, thus facilitating the development of cancer cachexia. In this review, physiological functions of P-selectin and its potential roles in cancer cachexia have been summarized. We also discuss the therapeutic potential of P-selectin inhibitors for the treatment of cancer cachexia.

Top Ten Tips Palliative Care Clinicians Should Know About Cachexia

Cachexia is a multifactorial syndrome that is common in cancer and chronic disease. It is often underdiagnosed and therefore goes untreated or undertreated. Cachexia causes suffering across biopsychosocial domains and affects patients and their loved ones. In this article, a group of clinicians and researchers across cancer care, nutrition, and exercise offers tips about assessment, classification, and management of cachexia, with attention to its stage. The required multimodal management of cachexia mirrors well the interprofessional collaboration that is the mainstay of interdisciplinary palliative care and attention to screening, diagnosis, and management of cachexia is critical to maximize patients' quality of life.

TNF-α-1031T/C gene polymorphism as a predictor of malnutrition in patients with gastric cancer

Introduction

Malnutrition is a complex clinical syndrome, the exact mechanism of which is yet not fully understood. Studies have found that malnutrition is associated with anorexia and inadequate intake, tumor depletion, leptin, tumor-induced metabolic abnormalities in the body, and catabolic factors produced by the tumor in the circulation and cytokines produced by the host immune system. Among these, single nucleotide polymorphisms (SNPs) are present in the gene encoding the pro-inflammatory cytokine TNF-α.

Aim

The objective of this study was to investigate TNF-α -1,031 T/C gene polymorphism as an unfavorable predictor of malnutrition in patients with gastric cancer.

Methods

The study group consisted of 220 gastric cancer patients treated at Affiliated Jinhua Hospital, Zhejiang University School of Medicine. Malnutrition was mainly assessed by the Global Consensus on Malnutrition Diagnostic Criteria (GLIM). DNA was extracted from peripheral leukocytes of whole blood samples using an animal DNA extraction kit. DNA was amplified using a 1.1× T3 Super PCR mixture and genotyped using SNP1 software.

Results

There are three major genetic polymorphisms in TNF-α. Among the 220 patients with gastric cancer, there were 7 patients with the CC genotype, 61 with the CT genotype and 152 with the TT genotype. Compared to patients with the TT genotype, patients with the C allele had an approximately 2.5-fold higher risk of developing malnutrition (p = 0.003; OR = 0.406). On the basis of multivariate analysis, patients with the CC genotype had an approximately 20.1-fold higher risk of developing malnutrition (p = 0.013; OR = 20.114), while those with the CT genotype had an almost 3.7-fold higher risk of malnutrition (p = 0.002; OR = 3.218).

Conclusion

SNP (-1,031 T/C) of the TNF-α may be a useful marker in the assessment of the risk of nutritional deficiencies in gastric cancer patients. Patients with gastric cancer carrying the C allele should be supported by early nutritional intervention, but more research is still needed to explore confirmation.

Molecular mechanisms of cancer cachexia-related loss of skeletal muscle mass: data analysis from preclinical and clinical studies

Cancer cachexia is a systemic hypoanabolic and catabolic syndrome that diminishes the quality of life of cancer patients, decreases the efficiency of therapeutic strategies and ultimately contributes to decrease their lifespan. The depletion of skeletal muscle compartment, which represents the primary site of protein loss during cancer cachexia, is of very poor prognostic in cancer patients. In this review, we provide an extensive and comparative analysis of the molecular mechanisms involved in the regulation of skeletal muscle mass in human cachectic cancer patients and in animal models of cancer cachexia. We summarize data from preclinical and clinical studies investigating how the protein turnover is regulated in cachectic skeletal muscle and question to what extent the transcriptional and translational capacities, as well as the proteolytic capacity (ubiquitin-proteasome system, autophagy-lysosome system and calpains) of skeletal muscle are involved in the cachectic syndrome in human and animals. We also wonder how regulatory mechanisms such as insulin/IGF1-AKT-mTOR pathway, endoplasmic reticulum stress and unfolded protein response, oxidative stress, inflammation (cytokines and downstream IL1ß/TNFα-NF-κB and IL6-JAK-STAT3 pathways), TGF-ß signalling pathways (myostatin/activin A-SMAD2/3 and BMP-SMAD1/5/8 pathways), as well as glucocorticoid signalling, modulate skeletal muscle proteostasis in cachectic cancer patients and animals. Finally, a brief description of the effects of various therapeutic strategies in preclinical models is also provided. Differences in the molecular and biochemical responses of skeletal muscle to cancer cachexia between human and animals (protein turnover rates, regulation of ubiquitin-proteasome system and myostatin/activin A-SMAD2/3 signalling pathways) are highlighted and discussed. Identifying the various and intertwined mechanisms that are deregulated during cancer cachexia and understanding why they are decontrolled will provide therapeutic targets for the treatment of skeletal muscle wasting in cancer patients.

Skeletal muscle omics signatures in cancer cachexia: perspectives and opportunities

Cachexia is a life-threatening complication of cancer that occurs in up to 80% of patients with advanced cancer. Cachexia reflects the systemic consequences of cancer and prominently features unintended weight loss and skeletal muscle wasting. Cachexia impairs cancer treatment tolerance, lowers quality of life, and contributes to cancer-related mortality. Effective treatments for cancer cachexia are lacking despite decades of research. High-throughput omics technologies are increasingly implemented in many fields including cancer cachexia to stimulate discovery of disease biology and inform therapy choice. In this paper, we present selected applications of omics technologies as tools to study skeletal muscle alterations in cancer cachexia. We discuss how comprehensive, omics-derived molecular profiles were used to discern muscle loss in cancer cachexia compared with other muscle-wasting conditions, to distinguish cancer cachexia from treatment-related muscle alterations, and to reveal severity-specific mechanisms during the progression of cancer cachexia from early toward severe disease.

Cachexia: A systemic consequence of progressive, unresolved disease

Cachexia, a systemic wasting condition, is considered a late consequence of diseases, including cancer, organ failure, or infections, and contributes to significant morbidity and mortality. The induction process and mechanistic progression of cachexia are incompletely understood. Refocusing academic efforts away from advanced cachexia to the etiology of cachexia may enable discoveries of new therapeutic approaches. Here, we review drivers, mechanisms, organismal predispositions, evidence for multi-organ interaction, model systems, clinical research, trials, and care provision from early onset to late cachexia. Evidence is emerging that distinct inflammatory, metabolic, and neuro-modulatory drivers can initiate processes that ultimately converge on advanced cachexia.

Thrombosis and cachexia in cancer: two partners in crime?

Among cancer patients, thrombosis and cachexia are major causes of morbidity and mortality. Although the two may occur together, little is known about their possible relationship. Thus, a literature review was conducted by screening the databases PubMed, Scopus, SciELO, Medline and Web of Science. To summarize, cancer-associated thrombosis (CAT) and cancer-associated cachexia (CAC) seem to share several patient-, tumour- and treatment-related risk factors. Inflammation alongside metabolic and endocrine derangement is the potential missing link between CAT, CAC and cancer. Many key players, including specific pro-inflammatory cytokines, immune cells and hormones, appear to be implicated in both thrombosis and cachexia, representing attractive predictive markers and potential therapeutic targets. Altogether, the current evidence suggests a link between CAT and CAC, however, epidemiological studies are required to explore this potential relationship. Given the high incidence and negative impact of both diseases, further studies are needed for the better management of cancer patients.

Body composition and lung cancer-associated cachexia in TRACERx

Cancer-associated cachexia (CAC) is a major contributor to morbidity and mortality in individuals with non-small cell lung cancer. Key features of CAC include alterations in body composition and body weight. Here, we explore the association between body composition and body weight with survival and delineate potential biological processes and mediators that contribute to the development of CAC. Computed tomography-based body composition analysis of 651 individuals in the TRACERx (TRAcking non-small cell lung Cancer Evolution through therapy (Rx)) study suggested that individuals in the bottom 20th percentile of the distribution of skeletal muscle or adipose tissue area at the time of lung cancer diagnosis, had significantly shorter lung cancer-specific survival and overall survival. This finding was validated in 420 individuals in the independent Boston Lung Cancer Study. Individuals classified as having developed CAC according to one or more features at relapse encompassing loss of adipose or muscle tissue, or body mass index-adjusted weight loss were found to have distinct tumor genomic and transcriptomic profiles compared with individuals who did not develop such features. Primary non-small cell lung cancers from individuals who developed CAC were characterized by enrichment of inflammatory signaling and epithelial-mesenchymal transitional pathways, and differentially expressed genes upregulated in these tumors included cancer-testis antigen MAGEA6 and matrix metalloproteinases, such as ADAMTS3. In an exploratory proteomic analysis of circulating putative mediators of cachexia performed in a subset of 110 individuals from TRACERx, a significant association between circulating GDF15 and loss of body weight, skeletal muscle and adipose tissue was identified at relapse, supporting the potential therapeutic relevance of targeting GDF15 in the management of CAC.

Identification and Characterization of Genomic Predictors of Sarcopenia and Sarcopenic Obesity Using UK Biobank Data

The substantial decline in skeletal muscle mass, strength, and gait speed is a sign of severe sarcopenia, which may partly depend on genetic risk factors. So far, hundreds of genome-wide significant single nucleotide polymorphisms (SNPs) associated with handgrip strength, lean mass and walking pace have been identified in the UK Biobank cohort; however, their pleiotropic effects on all three phenotypes have not been investigated. By combining summary statistics of genome-wide association studies (GWAS) of handgrip strength, lean mass and walking pace, we have identified 78 independent SNPs (from 73 loci) associated with all three traits with consistent effect directions. Of the 78 SNPs, 55 polymorphisms were also associated with body fat percentage and 25 polymorphisms with type 2 diabetes (T2D), indicating that sarcopenia, obesity and T2D share many common risk alleles. Follow-up bioinformatic analysis revealed that sarcopenia risk alleles were associated with tiredness, falls in the last year, neuroticism, alcohol intake frequency, smoking, time spent watching television, higher salt, white bread, and processed meat intake; whereas protective alleles were positively associated with bone mineral density, serum testosterone, IGF1, and 25-hydroxyvitamin D levels, height, intelligence, cognitive performance, educational attainment, income, physical activity, ground coffee drinking and healthier diet (muesli, cereal, wholemeal or wholegrain bread, potassium, magnesium, cheese, oily fish, protein, water, fruit, and vegetable intake). Furthermore, the literature data suggest that single-bout resistance exercise may induce significant changes in the expression of 26 of the 73 implicated genes in m. vastus lateralis, which may partly explain beneficial effects of strength training in the prevention and treatment of sarcopenia. In conclusion, we have identified and characterized 78 SNPs associated with sarcopenia and 55 SNPs with sarcopenic obesity in European-ancestry individuals from the UK Biobank.

Progressive development of melanoma-induced cachexia differentially impacts organ systems in mice

Cachexia is a systemic wasting syndrome that increases cancer-associated mortality. How cachexia progressively and differentially impacts distinct tissues is largely unknown. Here, we find that the heart and skeletal muscle undergo wasting at early stages and are the tissues transcriptionally most impacted by cachexia. We also identify general and organ-specific transcriptional changes that indicate functional derangement by cachexia even in tissues that do not undergo wasting, such as the brain. Secreted factors constitute a top category of cancer-regulated genes in host tissues, and these changes include upregulation of the angiotensin-converting enzyme (ACE). ACE inhibition with the drug lisinopril improves muscle force and partially impedes cachexia-induced transcriptional changes, although wasting is not prevented, suggesting that cancer-induced host-secreted factors can regulate tissue function during cachexia. Altogether, by defining prevalent and temporal and tissue-specific responses to cachexia, this resource highlights biomarkers and possible targets for general and tissue-tailored anti-cachexia therapies.

Targeting cancer cachexia: Molecular mechanisms and clinical study

Cancer cachexia is a complex systemic catabolism syndrome characterized by muscle wasting. It affects multiple distant organs and their crosstalk with cancer constitute cancer cachexia environment. During the occurrence and progression of cancer cachexia, interactions of aberrant organs with cancer cells or other organs in a cancer cachexia environment initiate a cascade of stress reactions and destroy multiple organs including the liver, heart, pancreas, intestine, brain, bone, and spleen in metabolism, neural, and immune homeostasis. The role of involved organs turned from inhibiting tumor growth into promoting cancer cachexia in cancer progression. In this review, we depicted the complicated relationship of cancer cachexia with the metabolism, neural, and immune homeostasis imbalance in multiple organs in a cancer cachexia environment and summarized the treatment progress in recent years. And we discussed the molecular mechanism and clinical study of cancer cachexia from the perspective of multiple organs metabolic, neurological, and immunological abnormalities. Updated understanding of cancer cachexia might facilitate the exploration of biomarkers and novel therapeutic targets of cancer cachexia.

TNFRSF1A Gene Polymorphism (−610 T > G, rs4149570) as a Predictor of Malnutrition and a Prognostic Factor in Patients Subjected to Intensity-Modulated Radiation Therapy Due to Head and Neck Cancer

Background: Malnutrition is a nutritional disorder observed in 52% of patients with head and neck cancer (HNC). Malnutrition is frequently related to the increased level of proinflammatory cytokines. In turn, ongoing inflammation is associated with increased catabolism of skeletal muscle and lipolysis. Tumor necrosis factor α (TNF-α) is a proinflammatory cytokine that plays a pivotal role in the development of malnutrition and cachexia in cancer patients. The aim of the study was to assess the relationship between a functional single-nucleotide polymorphism (SNP) −610 T > G (rs4149570) of the TNFRSF1A gene and the occurrence of nutritional disorders in patients subjected to RT due to HNC. Methods: The study group consisted of 77 patients with HNC treated at the Oncology Department of the Medical University in Lublin. Genotyping of the TNFRSF1A gene was performed using capillary electrophoresis (Genetic Analyzer 3500). Results: Multivariable analysis revealed that the TT genotype of the TNFRSF1A gene (−610 T > G) was an independent predictor of severe malnutrition (odds ratio—OR = 5.05; p = 0.0350). Moreover, the TT genotype of this gene was independently related to a higher risk of critical weight loss (CWL) (OR = 24.85; p = 0.0009). Conclusions: SNP (−610 T > G) of the TNFRSF1A may be a useful marker in the assessment of the risk of nutritional deficiencies in HNC patients treated with intensity-modulated radiotherapy (IMRT).

Poor Physical Capacity Combined With High Body Fat Percentage as an Independent Risk Factor for Incident Hypertension in Chinese Suburb-Dwelling Older Adults

Background

This study examined the effects of poor physical capacity and high body fat percentage (BF%) on the incidence of hypertension in Chinese suburb-dwelling older adults.

Methods

This study was conducted on 368 Chinese suburb-dwelling participants aged ≥ 60 years without hypertension (mean age: 66.74 ± 5.59 years, 48.9% men). Poor physical capacity is defined by the Asian Working Group for Sarcopenia (AWGS) criteria as grip strength &lt; 26 kg for men and &lt; 18 kg for women or walking speed &lt;0.8 m/s. High BF% was defined as values that are greater than the upper tertile for BF% as stratified by sex. The outcome was the incidence of hypertension.

Results

Overall, 5.7% of subjects had both poor physical capacity and high BF%. After the average follow-up duration of 2 years, the incidence of hypertension was 39.7%, and those experiencing both poor physical capacity and high BF% had the highest incidence (81.0%). After multivariate adjustments, the incidence of hypertension was associated with the combination of poor physical capacity and high BF% [odds ratio (OR) = 6.43, 95% CI = 1.91–21.64] but not solely with poor physical capacity (OR = 1.11, 95% CI = 0.55–2.25) or only high BF% (OR = 1.37, 95% CI = 0.80–2.34).

Conclusion

The combination of poor physical capacity and high BF% can significantly increase the incidence of hypertension in Chinese suburb-dwelling older adults. For hypertension prevention, ideally, we should strive toward decreasing body fat mass while simultaneously improving physical capacity.

Cancer Cachexia and Antitumor Immunity: Common Mediators and Potential Targets for New Therapies

Cancer cachexia syndrome (CCS) is a multifactorial metabolic syndrome affecting a significant proportion of patients. CCS is characterized by progressive weight loss, alterations of body composition and a systemic inflammatory status, which exerts a major impact on the host’s innate and adaptive immunity. Over the last few years, the development of immune checkpoint inhibitors (ICIs) transformed the treatment landscape for a wide spectrum of malignancies, creating an unprecedented opportunity for long term remissions in a significant subset of patients. Early clinical data indicate that CCS adversely impairs treatment outcomes of patients receiving ICIs. We herein reviewed existing evidence on the potential links between the mechanisms that promote the catabolic state in CCS and those that impair the antitumor immune response. We show that the biological mediators and processes leading to the development of CCS may also participate in the modulation and the sustainment of an immune suppressive tumor microenvironment and impaired anti-tumor immunity. Moreover, we demonstrate that the deregulation of the host’s metabolic homeostasis in cancer cachexia is associated with resistance to ICIs. Further research on the interrelation between cancer cachexia and anti-tumor immunity is required for the effective management of resistance to immunotherapy in this specific but large subgroup of ICI treated individuals.

Impact of TNF-α Gene Polymorphisms on Pancreatic and Non-Small Cell Lung Cancer-Induced Cachexia in Adult Egyptian Patients: A Focus on Pathogenic Trajectories

Background

Cachexia is a frequent syndrome in pancreatic and non-small cell lung (NSCL) cancer patients. The storm of cancer-induced inflammatory cytokines, in particular TNF-α, is a crucial pathogenic mechanism. Among the molecular alterations accused of cancer-induced cachexia, TNF-α 308 G/A (rs1800629) and −1031T/C (rs1799964) are single-nucleotide polymorphisms (SNPs) within the gene encoding this pro-inflammatory cytokine. Recent studies have demonstrated the crucial role of non-coding microRNAs (miRNAs) in pathogenesis of different diseases including cachexia. Moreover, the mechanistic cytokine signaling pathway of miR-155, as a TNF-α regulator, supports the involvement of SOCS1, TAB2, and Foxp3, which are direct targets of TNF-α gene.

Aim

A case–control study (NCT04131478) was conducted primarily to determine the incidence of TNF-α 308 G/A (rs1800629) and −1031T/C (rs1799964) gene polymorphisms in adult Egyptian patients with local/advanced or metastatic pancreatic or NSCL cancer and investigate both as cachexia risk factors. The association of gene polymorphism with cachexia severity and the expression of miR-155 in cachectic patients were analyzed. A mechanistic investigation of the cytokine signaling pathway, involving SOCS1, TAB2, and Foxp3, was also performed.

Results

In both pancreatic and NSCL cancer cohorts, the mutant TNF-α variant of 308 G/A was positively associated with cachexia; on the contrary, that of 1031T/C was negatively associated with cachexia in the NSCL cancer patients. MiR-155 was higher in cachexia and in alignment with its severity in the cachectic group as compared with the non-cachectic group in both the pancreatic and NSCL cancer patients. Though TAB2 did not change to any significant extent in cachectic patients, the levels of SOCS1 and Foxp3 were significantly lower in the cachectic group as compared with the non-cachectic group.

Conclusion

Carriers of the A allele 308 G/A gene and high miR-155 are at greater risk of cachexia in both the pancreatic and NSCL cancer patients; however, the mutant variant of 1031T/C gene is protective against cachexia in the NSCL cancer patients. Finally, high levels of miR-155 in the cachectic group lead to negative feedback inhibition of both SOCS1 and Foxp3 in both the pancreatic and NSCL cancer patients.

Genetic variation in genes regulating skeletal muscle regeneration and tissue remodelling associated with weight loss in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. COPD patients with cachexia or weight loss have increased risk of death independent of body mass index (BMI) and lung function. We tested the hypothesis genetic variation is associated with weight loss in COPD using a genome-wide association study approach.

METHODS

Participants with COPD (N = 4308) from three studies (COPDGene, ECLIPSE, and SPIROMICS) were analysed. Discovery analyses were performed in COPDGene with replication in SPIROMICS and ECLIPSE. In COPDGene, weight loss was defined as self-reported unintentional weight loss > 5% in the past year or low BMI (BMI < 20 kg/m2 ). In ECLIPSE and SPIROMICS, weight loss was calculated using available longitudinal visits. Stratified analyses were performed among African American (AA) and Non-Hispanic White (NHW) participants with COPD. Single variant and gene-based analyses were performed adjusting for confounders. Fine mapping was performed using a Bayesian approach integrating genetic association results with linkage disequilibrium and functional annotation. Significant gene networks were identified by integrating genetic regions associated with weight loss with skeletal muscle protein-protein interaction (PPI) data.

RESULTS

At the single variant level, only the rs35368512 variant, intergenic to GRXCR1 and LINC02383, was associated with weight loss (odds ratio = 3.6, 95% confidence interval = 2.3-5.6, P = 3.2 × 10-8 ) among AA COPD participants in COPDGene. At the gene level in COPDGene, EFNA2 and BAIAP2 were significantly associated with weight loss in AA and NHW COPD participants, respectively. The EFNA2 association replicated among AA from SPIROMICS (P = 0.0014), whereas the BAIAP2 association replicated in NHW from ECLIPSE (P = 0.025). The EFNA2 gene encodes the membrane-bound protein ephrin-A2 involved in the regulation of developmental processes and adult tissue homeostasis such as skeletal muscle. The BAIAP2 gene encodes the insulin-responsive protein of mass 53 kD (IRSp53), a negative regulator of myogenic differentiation. Integration of the gene-based findings participants with PPI data revealed networks of genes involved in pathways such as Rho and synapse signalling.

CONCLUSIONS

The EFNA2 and BAIAP2 genes were significantly associated with weight loss in COPD participants. Collectively, the integrative network analyses indicated genetic variation associated with weight loss in COPD may influence skeletal muscle regeneration and tissue remodelling.

Skeletal Muscle Deconditioning in Breast Cancer Patients Undergoing Chemotherapy: Current Knowledge and Insights From Other Cancers

Breast cancer represents the most commonly diagnosed cancer while neoadjuvant and adjuvant chemotherapies are extensively used in order to reduce tumor development and improve disease-free survival. However, chemotherapy also leads to severe off-target side-effects resulting, together with the tumor itself, in major skeletal muscle deconditioning. This review first focuses on recent advances in both macroscopic changes and cellular mechanisms implicated in skeletal muscle deconditioning of breast cancer patients, particularly as a consequence of the chemotherapy treatment. To date, only six clinical studies used muscle biopsies in breast cancer patients and highlighted several important aspects of muscle deconditioning such as a decrease in muscle fibers cross-sectional area, a dysregulation of protein turnover balance and mitochondrial alterations. However, in comparison with the knowledge accumulated through decades of intensive research with many different animal and human models of muscle atrophy, more studies are necessary to obtain a comprehensive understanding of the cellular processes implicated in breast cancer-mediated muscle deconditioning. This understanding is indeed essential to ultimately lead to the implementation of efficient preventive strategies such as exercise, nutrition or pharmacological treatments. We therefore also discuss potential mechanisms implicated in muscle deconditioning by drawing a parallel with other cancer cachexia models of muscle wasting, both at the pre-clinical and clinical levels.

Metabolic Remodeling in Skeletal Muscle Atrophy as a Therapeutic Target

Skeletal muscle is a highly responsive tissue, able to remodel its size and metabolism in response to external demand. Muscle fibers can vary from fast glycolytic to slow oxidative, and their frequency in a specific muscle is tightly regulated by fiber maturation, innervation, or external causes. Atrophic conditions, including aging, amyotrophic lateral sclerosis, and cancer-induced cachexia, differ in the causative factors and molecular signaling leading to muscle wasting; nevertheless, all of these conditions are characterized by metabolic remodeling, which contributes to the pathological progression of muscle atrophy. Here, we discuss how changes in muscle metabolism can be used as a therapeutic target and review the evidence in support of nutritional interventions and/or physical exercise as tools for counteracting muscle wasting in atrophic conditions.

Cancer-Mediated Muscle Cachexia: Etiology and Clinical Management

Muscle cachexia has a major detrimental impact on cancer patients, being responsible for 30% of all cancer deaths. It is characterized by a debilitating loss in muscle mass and function, which ultimately deteriorates patients' quality of life and dampens therapeutic treatment efficacy. Muscle cachexia stems from widespread alterations in whole-body metabolism as well as immunity and neuroendocrine functions and these global defects often culminate in aberrant signaling within skeletal muscle, causing muscle protein breakdown and attendant muscle atrophy. This review summarizes recent landmark discoveries that significantly enhance our understanding of the molecular etiology of cancer-driven muscle cachexia and further discuss emerging therapeutic approaches seeking to simultaneously target those newly discovered mechanisms to efficiently curb this lethal syndrome.

Understanding the common mechanisms of heart and skeletal muscle wasting in cancer cachexia

Cachexia is a severe complication of cancer that adversely affects the course of the disease, with currently no effective treatments. It is characterized by a progressive atrophy of skeletal muscle and adipose tissue, resulting in weight loss, a reduced quality of life, and a shortened life expectancy. Although the cachectic condition primarily affects the skeletal muscle, a tissue that accounts for ~40% of total body weight, cachexia is considered a multi-organ disease that involves different tissues and organs, among which the cardiac muscle stands out for its relevance. Patients with cancer often experience severe cardiac abnormalities and manifest symptoms that are indicative of chronic heart failure, including fatigue, shortness of breath, and impaired exercise tolerance. Furthermore, cardiovascular complications are among the major causes of death in cancer patients who experienced cachexia. The lack of effective treatments for cancer cachexia underscores the need to improve our understanding of the underlying mechanisms. Increasing evidence links the wasting of the cardiac and skeletal muscles to metabolic alterations, primarily increased energy expenditure, and to increased proteolysis, ensuing from activation of the major proteolytic machineries of the cell, including ubiquitin-dependent proteolysis and autophagy. This review aims at providing an overview of the key mechanisms of cancer cachexia, with a major focus on those that are shared by the skeletal and cardiac muscles.

Tertiary lymphoid organs are associated with the progression of kidney damage and regulated by interleukin-17A

Background: Tertiary lymphoid organs (TLOs) occur after multiple chronic kidney injuries. interleukin-17A (IL-17A) has been reported to associate with the development of TLOs in inflammatory diseases. However, regulation of the renal TLOs and its clinical significance to the pathogenesis of chronic kidney injury are unknown.

Methods: To evaluate the clinical significance and regulation of renal TLOs, we analyzed the progression of patients with kidney damage based on the existence and absence of TLOs in a larger multicenter cohort. We also blocked the recruitment of lymphocyte cells into the kidney by FTY720 (fingolimod) in vivo. Besides, we used aged IL-17A genetic knocked out mice and IL-17A-neutralizing antibody to explore the role of IL-17A in renal TLOs formation.

Results: We demonstrated that renal TLOs of IgA nephropathy patients were associated with disease severity and were independent risk factors for renal progression after adjustment for age, sex, mean arterial pressure, proteinuria and, baseline eGFR and MEST-C score, especially in the early stage. Plasma levels of TLO-related chemokines CXCL13, CCL19, and CCL21 were higher in patients with renal TLOs. Inhibiting the formation of renal TLOs by FTY720 could reduce the intrarenal inflammation and fibrosis, and early intervention was found to be more effective. IL-17A was increased in renal TLOs models, and genetic depletion of IL-17A or treatment with anti-IL-17A antibody resulted in a marked reduction of the TLOs formation as well as alleviation of renal inflammation and fibrosis.

Conclusion: These results indicate that TLOs are associated with the progression of kidney damage and regulated by IL-17A and may be effective targets for the treatment of kidney damage.

Cancer cachexia and skeletal muscle atrophy in clinical studies: what do we really know?

Research investigators have shown a growing interest in investigating alterations underlying skeletal muscle wasting in patients with cancer. However, skeletal muscle dysfunctions associated with cancer cachexia have mainly been studied in preclinical models. In the present review, we summarize the results of clinical studies in which skeletal muscle biopsies were collected from cachectic vs. non-cachectic cancer patients. Most of these studies suggest the presence of significant physiological alterations in skeletal muscle from cachectic cancer patients. We suggest a hypothesis, which connects structural and metabolic parameters that may, at least in part, be responsible for the skeletal muscle atrophy characteristic of cancer cachexia. Finally, we discuss the importance of a better standardization of the diagnostic criteria for cancer cachexia, as well as the requirement for additional clinical studies to improve the robustness of these conclusions.

Perioperative nutrition: Recommendations from the ESPEN expert group

BACKGROUND & AIMS

Malnutrition has been recognized as a major risk factor for adverse postoperative outcomes. The ESPEN Symposium on perioperative nutrition was held in Nottingham, UK, on 14-15 October 2018 and the aims of this document were to highlight the scientific basis for the nutritional and metabolic management of surgical patients.

METHODS

This paper represents the opinion of experts in this multidisciplinary field and those of a patient and caregiver, based on current evidence. It highlights the current state of the art.

RESULTS

Surgical patients may present with varying degrees of malnutrition, sarcopenia, cachexia, obesity and myosteatosis. Preoperative optimization can help improve outcomes. Perioperative fluid therapy should aim at keeping the patient in as near zero fluid and electrolyte balance as possible. Similarly, glycemic control is especially important in those patients with poorly controlled diabetes, with a stepwise increase in the risk of infectious complications and mortality per increasing HbA1c. Immobilization can induce a decline in basal energy expenditure, reduced insulin sensitivity, anabolic resistance to protein nutrition and muscle strength, all of which impair clinical outcomes. There is a role for pharmaconutrition, pre-, pro- and syn-biotics, with the evidence being stronger in those undergoing surgery for gastrointestinal cancer.

CONCLUSIONS

Nutritional assessment of the surgical patient together with the appropriate interventions to restore the energy deficit, avoid weight loss, preserve the gut microbiome and improve functional performance are all necessary components of the nutritional, metabolic and functional conditioning of the surgical patient.

Evaluation of physical function and its association with body composition, quality of life and biomarkers in cancer cachexia patients

BACKGROUND & AIMS

There are currently no approved treatments for cancer cachexia. One of the main barriers to developing a treatment for this indication is the lack of consensus on clinically important tools for assessing functional impairment in this setting. This issue is of critical importance because functional improvement is likely to be required for approval by regulatory agencies. This cross-sectional study aimed to evaluate various functional performance measures and establish their association with body composition, energy expenditure, biomarkers, and patient-reported quality of life (QOL).

METHODS

Physical function, body composition, energy expenditure, cytokines, testosterone, and patient-reported QOL were compared between men with solid tumors with cachexia (CAC; N = 48), without cachexia (CNC; N = 48), and weight-stable patients without cancer (CON; N = 37). Receiver Operator Characteristic curves and multivariate regression were performed to identify functional impairment cut-points and predictors of physical function, respectively.

RESULTS

Patients with CAC displayed lower total lean and appendicular lean mass, stair climb power (SCP), upper body strength, and bioavailable testosterone, and displayed higher energy expenditure than CNC or CON (p ≤ 0.03); CAC showed lower handgrip, respiratory quotient, and appetite, and higher cytokines and fatigue than CON (p ≤ 0.032). A cut-point of 336 Watts for SCP provided 78% sensitivity and 77% specificity for classification of CAC (p = 0.001); SCP also performed better than other measures tested when compared to CON-derived normatives. Upper body strength exhibited moderate sensitivity and specificity for classification of CAC (p ≤ 0.02). Elevated relative energy expenditure and cytokines negatively predicted, and muscle mass positively predicted, various muscle strength outcomes.

CONCLUSION

Stair climb power and upper body strength may have potential as discriminatory tests for functional impairment in patients with cancer cachexia.

MicroRNA-mRNA Co-sequencing Identifies Transcriptional and Post-transcriptional Regulatory Networks Underlying Muscle Wasting in Cancer Cachexia

Cancer cachexia is a metabolic syndrome with alterations in gene regulatory networks that consequently lead to skeletal muscle wasting. Integrating microRNAs-mRNAs omics profiles offers an opportunity to understand transcriptional and post-transcriptional regulatory networks underlying muscle wasting. Here, we used RNA sequencing to simultaneously integrate and explore microRNAs and mRNAs expression profiles in the tibialis anterior (TA) muscles of the Lewis Lung Carcinoma (LLC) model of cancer cachexia. We found 1,008 mRNAs and 18 microRNAs differentially expressed in cachectic mice compared with controls. Although our transcriptomic analysis demonstrated a high heterogeneity in mRNA profiles of cachectic mice, we identified a reduced number of differentially expressed genes that were uniformly regulated within cachectic muscles. This set of uniformly regulated genes is associated with the extracellular matrix (ECM), proteolysis, and inflammatory response. We also used transcriptomic data to perform enrichment analysis of transcriptional factor binding sites in promoter sequences, which revealed activation of the atrophy-related transcription factors NF-κB, Stat3, AP-1, and FoxO. Furthermore, the integration of mRNA and microRNA expression profiles identified post-transcriptional regulation by microRNAs of genes involved in ECM organization, cell migration, transcription factors binding, ion transport, and the FoxO signaling pathway. Our integrative analysis of microRNA-mRNA co-profiles comprehensively characterized regulatory relationships of molecular pathways and revealed microRNAs targeting ECM-associated genes in cancer cachexia.

Management of Cancer Cachexia: Attempting to Develop New Pharmacological Agents for New Effective Therapeutic Options

Cancer cachexia (CC) is a multifactorial syndrome characterized by systemic inflammation, uncontrolled weight loss and dramatic metabolic alterations. This includes myofibrillar protein breakdown, increased lipolysis, insulin resistance, elevated energy expediture, and reduced food intake, hence impairing the patient's response to anti-cancer therapies and quality of life. While a decade ago the syndrome was considered incurable, over the most recent years much efforts have been put into the study of such disease, leading to the development of potential therapeutic strategies. Several important improvements have been reached in the management of CC from both the diagnostic-prognostic and the pharmacological viewpoint. However, given the heterogeneity of the disease, it is impossible to rely only on single variables to properly treat patients presenting this metabolic syndrome. Moreover, the cachexia symptoms are strictly dependent on the type of tumor, stage and the specific patient's response to cancer therapy. Thus, the attempt to translate experimentally effective therapies into the clinical practice results in a great challenge. For this reason, it is of crucial importance to further improve our understanding on the interplay of molecular mechanisms implicated in the onset and progression of CC, giving the opportunity to develop new effective, safe pharmacological treatments. In this review we outline the recent knowledge regarding cachexia mediators and pathways involved in skeletal muscle (SM) and adipose tissue (AT) loss, mainly from the experimental cachexia standpoint, then retracing the unimodal treatment options that have been developed to the present day.

Clinical and biological characterization of skeletal muscle tissue biopsies of surgical cancer patients

BACKGROUND

Researchers increasingly use intraoperative muscle biopsy to investigate mechanisms of skeletal muscle atrophy in patients with cancer. Muscles have been assessed for morphological, cellular, and biochemical features. The aim of this study was to conduct a state-of-the-science review of this literature and, secondly, to evaluate clinical and biological variation in biopsies of rectus abdominis (RA) muscle from a cohort of patients with malignancies.

METHODS

Literature was searched for reports on muscle biopsies from patients with a cancer diagnosis. Quality of reports and risk of bias were assessed. Data abstracted included patient characteristics and diagnoses, sample size, tissue collection and biobanking procedures, and results. A cohort of cancer patients (n = 190, 88% gastrointestinal malignancies), who underwent open abdominal surgery as part of their clinical care, consented to RA biopsy from the site of incision. Computed tomography (CT) scans were used to quantify total abdominal muscle and RA cross-sectional areas and radiodensity. Biopsies were assessed for muscle fibre area (μm² ), fibre types, myosin heavy chain isoforms, and expression of genes selected for their involvement in catabolic pathways of muscle.

RESULTS

Muscle biopsy occurred in 59 studies (total N = 1585 participants). RA was biopsied intraoperatively in 40 studies (67%), followed by quadriceps (26%; percutaneous biopsy) and other muscles (7%). Cancer site and stage, % of male participants, and age were highly variable between studies. Details regarding patient medical history and biopsy procedures were frequently absent. Lack of description of the population(s) sampled and low sample size contributed to low quality and risk of bias. Weight-losing cases were compared with weight stable cancer or healthy controls without considering a measure of muscle mass in 21 out of 44 studies. In the cohort of patients providing biopsy for this study, 78% of patients had preoperative CT scans and a high proportion (64%) met published criteria for sarcopenia. Fibre type distribution in RA was type I (46% ± 13), hybrid type I/IIA (1% ± 1), type IIA (36% ± 10), hybrid type IIA/D (15% ± 14), and type IID (2% ± 5). Sexual dimorphism was prominent in RA CT cross-sectional area, mean fibre cross-sectional area, and in expression of genes associated with muscle growth, apoptosis, and inflammation (P < 0.05). Medical history revealed multiple co-morbid conditions and medications.

CONCLUSIONS

Continued collaboration between researchers and cancer surgeons enables a more complete understanding of mechanisms of cancer-associated muscle atrophy. Standardization of biobanking practices, tissue manipulation, patient characterization, and classification will enhance the consistency, reliability, and comparability of future studies.

Immunohistochemical phenotyping of T cells, granulocytes, and phagocytes in the muscle of cancer patients: association with radiologically defined muscle mass and gene expression

BACKGROUND

Inflammation is a recognized contributor to muscle wasting. Research in injury and myopathy suggests that interactions between the skeletal muscle and immune cells confer a pro-inflammatory environment that influences muscle loss through several mechanisms; however, this has not been explored in the cancer setting. This study investigated the local immune environment of the muscle by identifying the phenotype of immune cell populations in the muscle and their relationship to muscle mass in cancer patients.

METHODS

Intraoperative muscle biopsies were collected from cancer patients (n = 30, 91% gastrointestinal malignancies). Muscle mass was assessed histologically (muscle fiber cross-sectional area, CSA; μm²) and radiologically (lumbar skeletal muscle index, SMI; cm²/m² by computed tomography, CT). T cells (CD4 and CD8) and granulocytes/phagocytes (CD11b, CD14, and CD15) were assessed by immunohistochemistry. Microarray analysis was conducted in the muscle of a second cancer patient cohort.

RESULTS

T cells (CD3+), granulocytes/phagocytes (CD11b+), and CD3-CD4+ cells were identified. Muscle fiber CSA (μm²) was positively correlated (Spearman's r = > 0.45; p = < 0.05) with the total number of T cells, CD4, and CD8 T cells and granulocytes/phagocytes. In addition, patients with the smallest SMI exhibited fewer CD8 T cells within their muscle. Consistent with this, further exploration with gene correlation analyses suggests that the presence of CD8 T cells is negatively associated (Pearson's r = ≥ 0.5; p = <0.0001) with key genes within muscle catabolic pathways for signaling (ACVR2B), ubiquitin proteasome (FOXO4, TRIM63, FBXO32, MUL1, UBC, UBB, UBE2L3), and apoptosis/autophagy (CASP8, BECN1, ATG13, SIVA1).

CONCLUSION

The skeletal muscle immune environment of cancer patients is comprised of immune cell populations from the adaptive and innate immunity. Correlations of T cells, granulocyte/phagocytes, and CD3-CD4+ cells with muscle mass measurements indicate a positive relationship between immune cell numbers and muscle mass status in cancer patients. Further exploration with gene correlation analyses suggests that the presence of CD8 T cells is negatively correlated with components of muscle catabolism.

Expression of genes in the skeletal muscle of individuals with cachexia/sarcopenia: A systematic review

Background

Cachexia occurs in individuals affected by chronic diseases in which systemic inflammation leads to fatigue, debilitation, decreased physical activity and sarcopenia. The pathogenesis of cachexia-associated sarcopenia is not fully understood.

Objectives

The aim of this systematic review is to summarize the current evidence on genes expressed in the skeletal muscles of humans with chronic disease-associated cachexia and/or sarcopenia (cases) compared to controls and to assess the strength of such evidence.

Methods

We searched PubMed, EMBASE and CINAHL using three concepts: cachexia/sarcopenia and associated symptoms, gene expression, and skeletal muscle.

Results

Eighteen genes were studied in at least three research articles, for a total of 27 articles analyzed in this review. Participants were approximately 60 years of age and majority male; sample size was highly variable. Use of comparison groups, matching criteria, muscle biopsy location, and definitions of cachexia and sarcopenia were not homogenous. None of the studies fulfilled all four criteria used to assess the quality of molecular analysis, with only one study powered on the outcome of gene expression. FOXO1 was the only gene significantly increased in cases versus healthy controls. No study found a significant decrease in expression of genes involved in autophagy, apoptosis or inflammation in cases versus controls. Inconsistent or non-significant findings were reported for genes involved in protein degradation, muscle differentiation/growth, insulin/insulin growth factor-1 or mitochondrial transcription.

Conclusion

Currently available evidence on gene expression in the skeletal muscles of humans with chronic disease-associated cachexia and/or sarcopenia is not powered appropriately and is not homogenous; therefore, it is difficult to compare results across studies and diseases.

Cancer Takes a Toll on Skeletal Muscle by Releasing Heat Shock Proteins-An Emerging Mechanism of Cancer-Induced Cachexia

Cancer-associated cachexia (cancer cachexia) is a major contributor to the modality and mortality of a wide variety of solid tumors. It is estimated that cachexia inflicts approximately ~60% of all cancer patients and is the immediate cause of ~30% of all cancer-related death. However, there is no established treatment of this disorder due to the poor understanding of its underlying etiology. The key manifestations of cancer cachexia are systemic inflammation and progressive loss of skeletal muscle mass and function (muscle wasting). A number of inflammatory cytokines and members of the TGFβ superfamily that promote muscle protein degradation have been implicated as mediators of muscle wasting. However, clinical trials targeting some of the identified mediators have not yielded satisfactory results. Thus, the root cause of the muscle wasting associated with cancer cachexia remains to be identified. This review focuses on recent progress of laboratory studies in the understanding of the molecular mechanisms of cancer cachexia that centers on the role of systemic activation of Toll-like receptor 4 (TLR4) by cancer-released Hsp70 and Hsp90 in the development and progression of muscle wasting, and the downstream signaling pathways that activate muscle protein degradation through the ubiquitin-proteasome and the autophagy-lysosome pathways in response to TLR4 activation. Verification of these findings in humans could lead to etiology-based therapies of cancer cachexia by targeting multiple steps in this signaling cascade.

The Genome Landscape of Tibetan Sheep Reveals Adaptive Introgression from Argali and the History of Early Human Settlements on the Qinghai-Tibetan Plateau

Tibetan sheep are the most common and widespread domesticated animals on the Qinghai-Tibetan Plateau (QTP) and have played an essential role in the permanent human occupation of this high-altitude region. However, the precise timing, route, and process of sheep pastoralism in the QTP region remain poorly established, and little is known about the underlying genomic changes that occurred during the process. Here, we investigate the genomic variation in Tibetan sheep using whole-genome sequences, single nucleotide polymorphism arrays, mitochondrial DNA, and Y-chromosomal variants in 986 samples throughout their distribution range. We detect strong signatures of selection in genes involved in the hypoxia and ultraviolet signaling pathways (e.g., HIF-1 pathway and HBB and MITF genes) and in genes associated with morphological traits such as horn size and shape (e.g., RXFP2). We identify clear signals of argali (Ovis ammon) introgression into sympatric Tibetan sheep, covering 5.23-5.79% of their genomes. The introgressed genomic regions are enriched in genes related to oxygen transportation system, sensory perception, and morphological phenotypes, in particular the genes HBB and RXFP2 with strong signs of adaptive introgression. The spatial distribution of genomic diversity and demographic reconstruction of the history of Tibetan sheep show a stepwise pattern of colonization with their initial spread onto the QTP from its northeastern part ∼3,100 years ago, followed by further southwest expansion to the central QTP ∼1,300 years ago. Together with archeological evidence, the date and route reveal the history of human expansions on the QTP by the Tang-Bo Ancient Road during the late Holocene. Our findings contribute to a depth understanding of early pastoralism and the local adaptation of Tibetan sheep as well as the late-Holocene human occupation of the QTP.

Novel molecular targets of muscle wasting in cancer patients

PURPOSE OF REVIEW

Cancer-associated muscle wasting affects many patients and leads to reduced patient function, decreased quality of life and poor responses to surgical and oncological treatments. Despite advancements in the understanding of its pathophysiology, no current treatment or accepted strategy for successful management exists. In this review, we provide an update on potential novel therapeutic targets in cancer cachexia.

RECENT FINDINGS

Recent research has focused on molecular mechanisms underlying cancer-associated muscle wasting, allowing identification of potential therapeutic targets and the development of several promising drugs. However, due to the multifactorial and patient-specific pathogenesis of cachexia, the demonstration of a measurable and meaningful clinical effect in randomized controlled trials has proven difficult. Potential novel targets such as circulating macrophage inhibitory cytokine 1/growth differentiation factor 15 and ZRT/IRT-like protein 14 have shown relevance in animal models, but their therapeutic manipulation has yet to be translated to patients. Increasing evidence has suggested that a single therapy may not be successful and a targeted, multimodal approach is required.

SUMMARY

The management of cancer-associated muscle wasting is complex. Future clinical trials should focus on early multimodal therapeutic interventions involving targeted therapies, with careful deliberation of chosen nutritional and functional outcomes.

Energy metabolism in cachexia

Cachexia is a wasting disorder that accompanies many chronic diseases including cancer and results from an imbalance of energy requirements and energy uptake. In cancer cachexia, tumor-secreted factors and/or tumor-host interactions cause this imbalance, leading to loss of adipose tissue and skeletal and cardiac muscle, which weakens the body. In this review, we discuss how energy enters the body and is utilized by the different organs, including the gut, liver, adipose tissue, and muscle, and how these organs contribute to the energy wasting observed in cachexia. We also discuss futile cycles both between the organs and within the cells, which are often used to fine-tune energy supply under physiologic conditions. Ultimately, understanding the complex interplay of pathologic energy-wasting circuits in cachexia can bring us closer to identifying effective treatment strategies for this devastating wasting disease.

Relationship Between -2028 C/T SELP Gene Polymorphism, Concentration of Plasma P-Selectin and Risk of Malnutrition in Head and Neck Cancer Patients

Until today there is a lack of molecular factors, that could predict either cancer malnutrition or cachexia. Among potential mechanisms, that contribute to development of above syndromes, the systemic inflammatory response with overproduction of cytokines and adhesion molecules is the most likely. Recent papers suggested crucial role of P-selectin adhesion molecule in the initiation of leukocytes recruitment to the site of injury during inflammation, promotion of tumor aggressiveness and contribution to cancer cachexia. The aim of the study was to investigate SELP -2028 C/T polymorphism as a risk factor of malnutrition in 66 head and neck cancer (HNC) patients subjected to radiotherapy. Genotyping was conducted by real-time PCR method by means of TaqMan SNP Genotyping Assay. P-selectin Human ELISA Kit was used to determine P-selectin concentration in each extracted plasma samples. CC homozygous subjects had 4-fold higher risk score of being qualified as severely malnourished compared to other genotype carriers (p = 0.015). However, the TT homozygous patients were at lowest risk of severe weight loss >10% during the therapy period (OR = 0.20; p = 0.019). We also noted, that CC genotype carriers had significantly higher risk of early death incidence compared to CT or TT genotype (median survival time: 29 vs 34 months; HR = 3.02; p = 0.0085). Studied SELP -2028 C/T seems to be a novel attractive predictive factor of cancer malnutrition in HNC patients, perhaps in a future, patients carrying unfavorable CC genotype could be earlier scheduled for pharmaceutical intervention with parenterall nutrition, therefore they could be prevented from the development of severe malnutrition or even cachexia.

Mas Receptor Activation Slows Tumor Growth and Attenuates Muscle Wasting in Cancer

Cancer cachexia is a multifactorial syndrome characterized by a progressive loss of skeletal muscle mass associated with significant functional impairment. Cachexia robs patients of their strength and capacity to perform daily tasks and live independently. Effective treatments are needed urgently. Here, we investigated the therapeutic potential of activating the "alternative" axis of the renin-angiotensin system, involving ACE2, angiotensin-(1-7), and the mitochondrial assembly receptor (MasR), for treating cancer cachexia. Plasmid overexpression of the MasR or pharmacologic angiotensin-(1-7)/MasR activation did not affect healthy muscle fiber size in vitro or in vivo but attenuated atrophy induced by coculture with cancer cells in vitro. In mice with cancer cachexia, the MasR agonist AVE 0991 slowed tumor development, reduced weight loss, improved locomotor activity, and attenuated muscle wasting, with the majority of these effects dependent on the orexigenic and not antitumor properties of AVE 0991. Proteomic profiling and IHC revealed that mechanisms underlying AVE 0991 effects on skeletal muscle involved miR-23a-regulated preservation of the fast, glycolytic fibers. MasR activation is a novel regulator of muscle phenotype, and AVE 0991 has orexigenic, anticachectic, and antitumorigenic effects, identifying it as a promising adjunct therapy for cancer and other serious muscle wasting conditions. SIGNIFICANCE: These findings demonstrate that MasR activation has multiple benefits of being orexigenic, anticachectic, and antitumorigenic, revealing it as a potential adjunct therapy for cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/4/706/F1.large.jpg.See related commentary by Rupert et al., p. 699.

Relationship between TNF-α -1031T/C gene polymorphism, plasma level of TNF-α, and risk of cachexia in head and neck cancer patients

Background

Malnutrition and cachexia are frequent among head and neck cancer (HNC) patients and these syndromes are associated with both poor quality of life and unfavorable disease prognosis. Unfortunately, there are still no established biomarkers that could predict the development of cachexia. Among potential molecular alterations related to cancer cachexia, there are single-nucleotide polymorphisms (SNPs) within genes encoding pro-inflammatory cytokines such as TNF-α.

The aim of the study

To investigate TNF-α −1031T/C SNP as a risk factor of cachexia in 62 HNC patients subjected to radiotherapy. DNA was isolated from whole blood samples and genotyping was conducted using real-time PCR method by means of TaqMan SNP Genotyping Assay. TNF-alpha Human ELISA Kit was used to determine TNF-α concentration in each extracted plasma sample. Moreover, the relationship between genotype variants of TNF-α and plasma level of TNF-α was examined. Detailed clinical–demographic and nutritional data were collected from each study participant.

Results

CC genotype carriers were at a significantly higher risk of being qualified as cachectic compared with other genotype carriers (p = 0.044; HR = 3.724). Subjects, who carried CC genotype had significantly lower body mass compared to patients with TT and CT genotype (p = 0.045). Moreover, CC individuals had the highest TNF-α plasma level (median 10.70 ± 0.72 pg/mL, p = 0.006) among the studied cases. We also noted, that CC genotype carriers had significantly higher risk of early death incidence compared to other genotype carriers [overall survival (OS): 28 vs 38 months (HR = 3.630, p = 0.013)].

Conclusion

Despite the differences between SGA and NRS scoring, the presence of CC genotype could be a useful objective marker allowing for the prediction of cachexia development in both parenterally nourished and non-parenterally nourished patients. Patients with CC genotype had also the highest risk of early death incidence; therefore, such individuals should be qualified for parenteral nutrition and supportive care at the time of diagnosis to improve further therapy outcomes. Moreover, this is the first study demonstrating the relationship between TNF-α −1031T/C polymorphism and plasma level of TNF-α. This is also the first paper investigating the role of TNF-α −1031T/C in cancer cachexia.

Cancer-associated cachexia

Cancer-associated cachexia is a disorder characterized by loss of body weight with specific losses of skeletal muscle and adipose tissue. Cachexia is driven by a variable combination of reduced food intake and metabolic changes, including elevated energy expenditure, excess catabolism and inflammation. Cachexia is highly associated with cancers of the pancreas, oesophagus, stomach, lung, liver and bowel; this group of malignancies is responsible for half of all cancer deaths worldwide. Cachexia involves diverse mediators derived from the cancer cells and cells within the tumour microenvironment, including inflammatory and immune cells. In addition, endocrine, metabolic and central nervous system perturbations combine with these mediators to elicit catabolic changes in skeletal and cardiac muscle and adipose tissue. At the tissue level, mechanisms include activation of inflammation, proteolysis, autophagy and lipolysis. Cachexia associates with a multitude of morbidities encompassing functional, metabolic and immune disorders as well as aggravated toxicity and complications of cancer therapy. Patients experience impaired quality of life, reduced physical, emotional and social well-being and increased use of healthcare resources. To date, no effective medical intervention completely reverses cachexia and there are no approved drug therapies. Adequate nutritional support remains a mainstay of cachexia therapy, whereas drugs that target overactivation of catabolic processes, cell injury and inflammation are currently under investigation.

An analysis of the types of recently published research in the field of cachexia

Introduction Cachexia is a common complication of many and varied chronic disease processes, yet it has received very little attention as an area of clinical research effort until recently. We sought to survey the contemporary literature on published research into cachexia to define where it is being published and the proportion of output classified into the main types of research output. Methods I searched the PubMed listings under the topic research term "cachexia" and related terms for articles published in the calendar years of 2015 and 2016, regardless of language. Searches were conducted and relevant papers extracted by two observers, and disagreements were resolved by consensus. Results There were 954 publications, 370 of which were review articles or commentaries, 254 clinical observations or non-randomised trials, 246 original basic science reports and only 26 were randomised controlled trials. These articles were published in 478 separate journals but with 36% of them being published in a core set of 23 journals. The H-index of these papers was 25 and there were 147 papers with 10 or more citations. Of the top 100 cited papers, 25% were published in five journals. Of the top cited papers, 48% were review articles, 18% were original basic science, and 7% were randomised clinical trials. Discussion This analysis shows a steady but modest increase in publications concerning cachexia with a strong pipeline of basic science research but still a relative lack of randomised clinical trials, with none exceeding 1000 patients. Research in cachexia is still in its infancy, but the solid basic science effort offers hope that translation into randomised controlled clinical trials may eventually lead to effective therapies for this troubling and complex clinical disease process.

Biomarkers of cancer cachexia

Cachexia is a complex multifactorial syndrome, characterized by loss of skeletal muscle and fat mass, which affects the majority of advanced cancer patients and is associated with poor prognosis. Interestingly, reversing muscle loss in animal models of cancer cachexia leads to prolong survival. Therefore, detecting cachexia and maintaining muscle mass represent a major goal in the care of cancer patients. However, early diagnosis of cancer cachexia is currently limited for several reasons. Indeed, cachexia development is variable according to tumor and host characteristics. In addition, safe, accessible and non-invasive tools to detect skeletal muscle atrophy are desperately lacking in clinical practice. Finally, the precise molecular mechanisms and the key players involved in cancer cachexia remain poorly characterized. The need for an early diagnosis of cancer cachexia supports therefore the quest for a biomarker that might reflect skeletal muscle atrophy process. Current research offers different promising ways to identify such a biomarker. Initially, the quest for a biomarker of cancer cachexia has mostly focused on mediators of muscle atrophy, produced by both tumor and host, in an attempt to define new therapeutic approaches. In another hand, molecules released by the muscle into the circulation during the atrophy process have been also considered as potential biomarkers. More recently, several "omics" studies are emerging to identify new muscular or circulating markers of cancer cachexia. Some genetic markers could also contribute to identify patients more susceptible to develop cachexia. This article reviews our current knowledge regarding potential biomarkers of cancer cachexia.

New genetic signatures associated with cancer cachexia as defined by low skeletal muscle index and weight loss

BACKGROUND

Cachexia affects the majority with advanced cancer. Based on current demographic and clinical factors, it is not possible to predict who will develop cachexia or not. Such variation may, in part, be due to genotype. It has recently been proposed to extend the diagnostic criteria for cachexia to include a direct measure of low skeletal muscle index (LSMI) in addition to weight loss (WL). We aimed to explore our panel of candidate single nucleotide polymorphism (SNPs) for association with WL +/- computerized tomography-defined LSMI. We also explored whether the transcription in muscle of identified genes was altered according to such cachexia phenotype METHODS: A retrospective cohort study design was used. Analysis explored associations of candidate SNPs with WL (n = 1276) and WL + LSMI (n = 943). Human muscle transcriptome (n = 134) was analysed using an Agilent platform.

RESULTS

Single nucleotide polymorphisms in the following genes showed association with WL alone: GCKR, LEPR, SELP, ACVR2B, TLR4, FOXO3, IGF1, CPN1, APOE, FOXO1, and GHRL. SNPs in LEPR, ACVR2B, TNF, and ACE were associated with concurrent WL + LSMI. There was concordance between muscle-specific expression for ACVR2B, FOXO1 and 3, LEPR, GCKR, and TLR4 genes and LSMI and/or WL (P < 0.05).

CONCLUSIONS

The rs1799964 in the TNF gene and rs4291 in the ACE gene are new associations when the definition of cachexia is based on a combination of WL and LSMI. These findings focus attention on pro-inflammatory cytokines and the renin-angiotensin system as biomarkers/mediators of muscle wasting in cachexia.