Nutritional leucine supplementation attenuates cardiac failure in tumour-bearing cachectic animals

Cardio-oncological dialogue: Understanding the mechanistic correlation between heart failure and cancer

AIMS

This review aims to elucidate the bidirectional relationship between heart failure and cancer by identifying their common and reciprocal risk factors. It seeks to provide a comprehensive understanding of the mechanistic interactions between these two conditions, supported by evidence from preclinical and clinical investigations.

MATERIALS AND METHODS

A thorough review of peer-reviewed articles was conducted to identify all possible interactions between cancer and heart failure. Multiple search engines were utilized with queries incorporating terms such as cardio-oncology, heart failure, cancer, risk factors, and mechanistic interactions. Selected studies were analysed to identify shared risk factors and to explore the mechanistic junctions that link the two diseases.

KEY FINDINGS

The review identified several common risk factors, including, inflammation, smoking, obesity, clonal haematopoiesis of indeterminate potential, and reduced exercise potential. The pathophysiological mechanisms linking heart failure with cancer include metabolic reprogramming in cancer, cancer-induced thrombosis, cardiac metastasis, paraneoplastic syndrome, cancer-associated cachexia, and anorexia. Additionally, it was found that cancer therapies, such as anthracyclines and radiation, can induce cardiotoxicity, leading to heart failure. The pathophysiological mechanisms that contribute to cancer in heart failure patients were identified as neurohormonal activation, state of hypoxia, secretion of Cardiokines, heart failure medication, innate immune reprograming & cardiac remodelling and coronary atherosclerotic disease.

SIGNIFICANCE

By highlighting the interconnected nature of heart failure and cancer, this review promotes a cardio-oncologic discourse, encouraging cardiologists and oncologists to consider these diseases as interrelated rather than separate entities. This perspective can lead to the development of novel therapeutic strategies and improve patient management by addressing the dual disease burden. Future research should focus on exploring the translational potential of existing drugs and developing new interventions to target the shared characteristics of heart failure and cancer.

High gestational leucine level dampens WDPCP/MAPK signaling to impair the EMT and migration of cardiac microvascular endothelial cells in congenital heart defects

Congenital heart defects (CHDs) represent one of the most prevalent categories of neonatal defects, and maternal dietary patterns have been linked to the risk of these conditions. Branched-chain amino acids (BCAAs), particularly leucine, are essential for various metabolic and physiological processes involved in heart development. In this study, we examined the molecular mechanisms through which elevated levels of leucine induce defects in cardiac microvascular endothelial cells. We collected plasma samples from healthy controls and neonatal patients with CHDs, employed a high-leucine diet for pregnant female mice, and applied high-leucine treatment in human cardiac microvascular endothelial cells (HCMECs). The impacts of high-leucine levels on WD Repeat Containing Planar Cell Polarity Effector (WDPCP)/MAPK signaling axis were investigated in the cell and animal models. We reported heightened plasma leucine levels in neonatal patients with CHDs and observed that a high-leucine diet in pregnant mice was associated with reduced expression of WDPCP and attenuated MAPK/ERK signaling. High-leucine treatment in HCMECs impaired epithelial-mesenchymal transition (EMT) and cell migration; however, overexpression of WDPCP or activation of MAPK exhibited a rescue effect. The upregulation of endomucin (EMCN) under high-leucine conditions contributed to the impaired EMT and migratory capacity of HCMECs, and the WDPCP/MAPK signaling axis regulated EMCN overexpression in response to high-leucine treatment. High levels of leucine in neonatal patients with CHDs may inhibit the WDPCP/MAPK axis, leading to an increase in EMCN expression that undermines the function of cardiac microvascular endothelial cells. These findings suggest the potential of targeting the WDPCP/MAPK axis as an intervention strategy for neonatal CHDs.

The prognostic value of bioinformatics analysis of ECM receptor signaling pathways and LAMB1 identification as a promising prognostic biomarker of lung adenocarcinoma

The extracellular matrix (ECM) is a complex and dynamic network of cross-linked proteins and a fundamental building block in multicellular organisms. Our study investigates the impact of genes related to the ECM receptor interaction pathway on immune-targeted therapy and lung adenocarcinoma (LUAD) prognosis. This study obtained LUAD chip data (GSE68465, GSE31210, and GSE116959) from NCBI GEO. Moreover, the gene data associated with the ECM receptor interaction pathway was downloaded from the Molecular Signature Database. Differentially expressed genes were identified using GEO2R, followed by analyzing their correlation with immune cell infiltration. Univariate Cox regression analysis screened out ECM-related genes significantly related to the survival prognosis of LUAD patients. Additionally, Lasso regression and multivariate Cox regression analysis helped construct a prognostic model. Patients were stratified by risk score and survival analyses. The prognostic models were evaluated using receiver operating characteristic curves, and risk scores and prognosis associations were analyzed using univariate and multivariate Cox regression analyses. A core gene was selected for gene set enrichment analysis and CIBERSORT analysis to determine its function and tumor-infiltrating immune cell proportion, respectively. The results revealed that the most abundant pathways among differentially expressed genes in LUAD primarily involved the cell cycle, ECM receptor interaction, protein digestion and absorption, p53 signaling pathway, complement and coagulation cascade, and tyrosine metabolism. Two ECM-associated subtypes were identified by consensus clustering. Besides, an ECM-related prognostic model was validated to predict LUAD survival, and it was associated with the tumor immune microenvironment. Additional cross-analysis screened laminin subunit beta 1 (LAMB1) for further research. The survival time of LUAD patients with elevated LAMB1 expression was longer than those with low LAMB1 expression. Gene set enrichment analysis and CIBERSORT analyses revealed that LAMB1 expression correlated with tumor immune microenvironment. In conclusion, a prognostic model of LUAD patients depending on the ECM receptor interaction pathway was constructed. Screening out LAMB1 can become a prognostic risk factor for LUAD patients or a potential target during LUAD treatment.

Therapy-naïve malignancy causes cardiovascular disease: a state-of-the-art cardio-oncology perspective

Cardiovascular disease (CVD) and cancer are the leading causes of mortality worldwide. Although generally thought of as distinct diseases, the intersectional overlap between CVD and cancer is increasingly evident in both causal and mechanistic relationships. The field of cardio-oncology is largely focused on the cardiotoxic effects of cancer therapies (e.g., chemotherapy, radiation). Furthermore, the cumulative effects of cardiotoxic therapy exposure and the prevalence of CVD risk factors in patients with cancer lead to long-term morbidity and poor quality of life in this patient population, even when patients are cancer-free. Evidence from patients with cancer and animal models demonstrates that the presence of malignancy itself, independent of cardiotoxic therapy exposure or CVD risk factors, negatively impacts cardiac structure and function. As such, the primary focus of this review is the cardiac pathophysiological and molecular features of therapy-naïve cancer. We also summarize the strengths and limitations of preclinical cancer models for cardio-oncology research and discuss therapeutic strategies that have been tested experimentally for the treatment of cancer-induced cardiac atrophy and dysfunction. Finally, we explore an adjacent area of interest, called "reverse cardio-oncology," where the sequelae of heart failure augment cancer progression. Here, we emphasize the cross-disease communication between malignancy and the injured heart and discuss the importance of chronic low-grade inflammation and endocrine factors in the progression of both diseases.

Leucine Supplementation Improves Diastolic Function in HFpEF by HDAC4 Inhibition

Heart failure with preserved ejection fraction (HFpEF) is a complex syndrome associated with a high morbidity and mortality rate. Leucine supplementation has been demonstrated to attenuate cardiac dysfunction in animal models of cachexia and heart failure with reduced ejection fraction (HFrEF). So far, no data exist on leucine supplementation on cardiac function in HFpEF. Thus, the current study aimed to investigate the effect of leucine supplementation on myocardial function and key signaling pathways in an established HFpEF rat model. Female ZSF1 rats were randomized into three groups: Control (untreated lean rats), HFpEF (untreated obese rats), and HFpEF_Leu (obese rats receiving standard chow enriched with 3% leucine). Leucine supplementation started at 20 weeks of age after an established HFpEF was confirmed in obese rats. In all animals, cardiac function was assessed by echocardiography at baseline and throughout the experiment. At the age of 32 weeks, hemodynamics were measured invasively, and myocardial tissue was collected for assessment of mitochondrial function and for histological and molecular analyses. Leucine had already improved diastolic function after 4 weeks of treatment. This was accompanied by improved hemodynamics and reduced stiffness, as well as by reduced left ventricular fibrosis and hypertrophy. Cardiac mitochondrial respiratory function was improved by leucine without alteration of the cardiac mitochondrial content. Lastly, leucine supplementation suppressed the expression and nuclear localization of HDAC4 and was associated with Protein kinase A activation. Our data show that leucine supplementation improves diastolic function and decreases remodeling processes in a rat model of HFpEF. Beneficial effects were associated with HDAC4/TGF-β1/Collagenase downregulation and indicate a potential use in the treatment of HFpEF.

The impact of inflammation and acute phase activation in cancer cachexia

The development of cachexia in the setting of cancer or other chronic diseases is a significant detriment for patients. Cachexia is associated with a decreased ability to tolerate therapies, reduction in ambulation, reduced quality of life, and increased mortality. Cachexia appears intricately linked to the activation of the acute phase response and is a drain on metabolic resources. Work has begun to focus on the important inflammatory factors associated with the acute phase response and their role in the immune activation of cachexia. Furthermore, data supporting the liver, lung, skeletal muscle, and tumor as all playing a role in activation of the acute phase are emerging. Although the acute phase is increasingly being recognized as being involved in cachexia, work in understanding underlying mechanisms of cachexia associated with the acute phase response remains an active area of investigation and still lack a holistic understanding and a clear causal link. Studies to date are largely correlative in nature, nonetheless suggesting the possibility for a role for various acute phase reactants. Herein, we examine the current literature regarding the acute phase response proteins, the evidence these proteins play in the promotion and exacerbation of cachexia, and current evidence of a therapeutic potential for patients.

Dietary Manipulation of Amino Acids for Cancer Therapy

Cancer cells cannot proliferate and survive unless they obtain sufficient levels of the 20 proteinogenic amino acids (AAs). Unlike normal cells, cancer cells have genetic and metabolic alterations that may limit their capacity to obtain adequate levels of the 20 AAs in challenging metabolic environments. However, since normal diets provide all AAs at relatively constant levels and ratios, these potentially lethal genetic and metabolic defects are eventually harmless to cancer cells. If we temporarily replace the normal diet of cancer patients with artificial diets in which the levels of specific AAs are manipulated, cancer cells may be unable to proliferate and survive. This article reviews in vivo studies that have evaluated the antitumor activity of diets restricted in or supplemented with the 20 proteinogenic AAs, individually and in combination. It also reviews our recent studies that show that manipulating the levels of several AAs simultaneously can lead to marked survival improvements in mice with metastatic cancers.

Role of mitochondrial metabolic disorder and immune infiltration in diabetic cardiomyopathy: new insights from bioinformatics analysis

BACKGROUND

Diabetic cardiomyopathy (DCM) is one of the common cardiovascular complications of diabetes and a leading cause of death in diabetic patients. Mitochondrial metabolism and immune-inflammation are key for DCM pathogenesis, but their crosstalk in DCM remains an open issue. This study explored the separate roles of mitochondrial metabolism and immune microenvironment and their crosstalk in DCM with bioinformatics.

METHODS

DCM chip data (GSE4745, GSE5606, and GSE6880) were obtained from NCBI GEO, while mitochondrial gene data were downloaded from MitoCarta3.0 database. Differentially expressed genes (DEGs) were screened by GEO2R and processed for GSEA, GO and KEGG pathway analyses. Mitochondria-related DEGs (MitoDEGs) were obtained. A PPI network was constructed, and the hub MitoDEGs closely linked to DCM or heart failure were identified with CytoHubba, MCODE and CTD scores. Transcription factors and target miRNAs of the hub MitoDEGs were predicted with Cytoscape and miRWalk database, respectively, and a regulatory network was established. The immune infiltration pattern in DCM was analyzed with ImmuCellAI, while the relationship between MitoDEGs and immune infiltration abundance was investigated using Spearman method. A rat model of DCM was established to validate the expression of hub MitoDEGs and their relationship with cardiac function.

RESULTS

MitoDEGs in DCM were significantly enriched in pathways involved in mitochondrial metabolism, immunoregulation, and collagen synthesis. Nine hub MitoDEGs closely linked to DCM or heart failure were obtained. Immune analysis revealed significantly increased infiltration of B cells while decreased infiltration of DCs in immune microenvironment of DCM. Spearman analysis demonstrated that the hub MitoDEGs were positively associated with the infiltration of pro-inflammatory immune cells, but negatively associated with the infiltration of anti-inflammatory or regulatory immune cells. In the animal experiment, 4 hub MitoDEGs (Pdk4, Hmgcs2, Decr1, and Ivd) showed an expression trend consistent with bioinformatics analysis result. Additionally, the up-regulation of Pdk4, Hmgcs2, Decr1 and the down-regulation of Ivd were distinctly linked to reduced cardiac function.

CONCLUSIONS

This study unraveled the interaction between mitochondrial metabolism and immune microenvironment in DCM, providing new insights into the research on potential pathogenesis of DCM and the exploration of novel targets for medical interventions.

Leucine Supplementation in Cancer Cachexia: Mechanisms and a Review of the Pre-Clinical Literature

Cancer cachexia (CC) is a complex syndrome of bodily wasting and progressive functional decline. Unlike starvation, cachexia cannot be reversed by increased energy intake alone. Nonetheless, targeted nutritional support is a necessary component in multimodal syndrome management. Due to the highly catabolic nature of cancer cachexia, amino acid supplementation has been proposed. Interestingly, leucine has been found to increase protein synthesis and decrease protein degradation via mTORC1 pathway activation. Multiple pre-clinical studies have explored the impact of leucine supplementation in cachectic tumor-bearing hosts. Here, we provide an overview of leucine’s proposed modes of action to preserve lean mass in cachexia and review the current pre-clinical literature related to leucine supplementation during CC. Current research indicates that a leucine-rich diet may attenuate CC symptomology; however, these works are difficult to compare due to methodological differences. There is need for further pre-clinical work exploring leucine’s potential ability to modulate protein turnover and immune response during CC, as well as the impact of additive leucine on tumor growth.

Review of Mechanisms and Treatment of Cancer-Induced Cardiac Cachexia

Cancer cachexia is a multifactorial, paraneoplastic syndrome that impacts roughly half of all cancer patients. It can negatively impact patient quality of life and prognosis by causing physical impairment, reducing chemotherapy tolerance, and precluding them as surgical candidates. While there is substantial research on cancer-induced skeletal muscle cachexia, there are comparatively fewer studies and therapies regarding cardiac cachexia in the setting of malignancy. A literature review was performed using the PubMed database to identify original articles pertaining to cancer-induced cardiac cachexia, including its mechanisms and potential therapeutic modalities. Seventy studies were identified by two independent reviewers based on inclusion and exclusion criteria. While there are multiple studies addressing the pathophysiology of cardiac-induced cancer cachexia, there are no studies evaluating therapeutic options in the clinical setting. Many treatment modalities including nutrition, heart failure medication, cancer drugs, exercise, and gene therapy have been explored in in vitro and mice models with varying degrees of success. While these may be beneficial in cancer patients, further prospective studies specifically focusing on the assessment and treatment of the cardiac component of cachexia are needed.

Involvement of the Parathyroid Hormone-Related Protein on Changes in the CYP3A Expression in Cancer Cachexia

Parathyroid hormone-related protein (PTHrP), which is secreted from a tumor, contributes to the progression of cachexia, a condition that is observed in half of all cancer patients. Although drug clearance was reported to decrease in patients with cancer cachexia, the details have not been clarified. The present study reports on an investigation of whether PTHrP is involved in the alternation of drug metabolism in cases of cancer cachexia. Cancer cachexia model rats with elevated serum PTHrP levels showed a significant decrease in hepatic and intestinal CYP3A2 protein expression. When midazolam, a CYP3A substrate drug, was administered intravenously or orally to the cancer cachexia rats, its area under the curve (AUC) was increased by about 2 and 5 times, as compared to the control group. Accordingly, the bioavailability of midazolam was increased by about 3 times, thus enhancing its pharmacological effect. In vitro experiments using HepG2 cells and Caco-2 cells showed that the addition of serum from cancer cachexia rats or active PTHrP (1-34) to each cell resulted in a significant decrease in the expression of CYP3A4 mRNA. Treatment with a cell-permeable cAMP analog also resulted in a decreased CYP3A4 expression. Pretreatment with protein kinase A (PKA), protein kinase C (PKC), and nuclear factor-kappa B (NF-κB) inhibitors recovered the decrease in CYP3A4 expression that was induced by PTHrP (1-34). These results suggest that PTHrP suppresses CYP3A expression via the cAMP/PKA/PKC/NF-κB pathway. Therefore, it is likely that PTHrP would be involved in the changes in drug metabolism observed in cancer cachexia.

Metabolism and Chronic Inflammation: The Links Between Chronic Heart Failure and Comorbidities

Heart failure (HF) patients often suffer from multiple comorbidities, such as diabetes, atrial fibrillation, depression, chronic obstructive pulmonary disease, and chronic kidney disease. The coexistance of comorbidities usually leads to multi morbidity and poor prognosis. Treatments for HF patients with multi morbidity are still an unmet clinical need, and finding an effective therapy strategy is of great value. HF can lead to comorbidity, and in return, comorbidity may promote the progression of HF, creating a vicious cycle. This reciprocal correlation indicates there may be some common causes and biological mechanisms. Metabolism remodeling and chronic inflammation play a vital role in the pathophysiological processes of HF and comorbidities, indicating metabolism and inflammation may be the links between HF and comorbidities. In this review, we comprehensively discuss the major underlying mechanisms and therapeutic implications for comorbidities of HF. We first summarize the potential role of metabolism and inflammation in HF. Then, we give an overview of the linkage between common comorbidities and HF, from the perspective of epidemiological evidence to the underlying metabolism and inflammation mechanisms. Moreover, with the help of bioinformatics, we summarize the shared risk factors, signal pathways, and therapeutic targets between HF and comorbidities. Metabolic syndrome, aging, deleterious lifestyles (sedentary behavior, poor dietary patterns, smoking, etc.), and other risk factors common to HF and comorbidities are all associated with common mechanisms. Impaired mitochondrial biogenesis, autophagy, insulin resistance, and oxidative stress, are among the major mechanisms of both HF and comorbidities. Gene enrichment analysis showed the PI3K/AKT pathway may probably play a central role in multi morbidity. Additionally, drug targets common to HF and several common comorbidities were found by network analysis. Such analysis has already been instrumental in drug repurposing to treat HF and comorbidity. And the result suggests sodium-glucose transporter-2 (SGLT-2) inhibitors, IL-1β inhibitors, and metformin may be promising drugs for repurposing to treat multi morbidity. We propose that targeting the metabolic and inflammatory pathways that are common to HF and comorbidities may provide a promising therapeutic strategy.

Metabolomic signatures of cardiac remodelling and heart failure risk in the community

Aims

Heart failure (HF) is associated with several metabolic changes, but it is unknown whether distinct components of the circulating metabolome may be related to cardiac structure and function, and with incident HF in the community.

Methods and results

We assayed 217 circulating metabolites in 2336 Framingham Study participants (mean age 55 ± 10 years, 53% women) without HF at baseline. We used linear and Cox regression to relate concentrations of metabolites to left ventricular (LV) diastolic dimension, LV wall thickness, LV ejection fraction, left atrial dimension, LV ventricular mass, and aortic root size cross‐sectionally and to incident HF prospectively. Bonferroni‐adjusted P‐values <0.05 denoted statistical significance. Circulating concentrations of kynurenine [β = −0.12 cm per standard deviation (SD) increment in normalized residual of metabolite, P = 7.3 × 10⁻⁸] and aminoadipate (−0.11 cm per SD increment, P = 2.61 × 10⁻⁵) were associated with left ventricular diastolic dimension, phosphatidylcholine (carbon:double bound = 38:6) with left atrial dimension (0.10 cm per SD increment, P = 9.7 × 10⁻⁶), and cholesterol ester (carbon:double bound = 20:5) with left atrial dimension (0.10 cm per SD increment, P = 1.4 × 10⁻⁵) in multivariable‐adjusted models. During an average follow‐up of 15.8 (range 0.02–23.2) years, 113 participants (5%) were diagnosed with HF with reduced ejection fraction and 106 individuals (5%) with HF with preserved ejection fraction. In multivariable analyses, concentrations of phosphatidylcholine (hazard ratio 0.63, P = 1.3 × 10⁻⁵) and ornithine (hazard ratio 1.44, P = 0.00014) were associated with HF with reduced ejection fraction.

Conclusions

Several metabolites, including the vasoactive metabolite kynurenine, were related to cardiac structure and function in our sample. Additional research is warranted to confirm our observations and investigate if these metabolites can risk stratify ambulatory individuals.

Leucine-Rich Diet Modulates the Metabolomic and Proteomic Profile of Skeletal Muscle during Cancer Cachexia

Background: Cancer-cachexia induces a variety of metabolic disorders, including skeletal muscle imbalance. Alternative therapy, as nutritional supplementation with leucine, shows a modulatory effect over tumour damage in vivo and in vitro. Method: Adult rats distributed into Control (C), Walker tumour-bearing (W), control fed a leucine-rich diet (L), and tumour-bearing fed a leucine-rich diet (WL) groups had the gastrocnemius muscle metabolomic and proteomic assays performed in parallel to in vitro assays. Results: W group presented an affected muscle metabolomic and proteomic profile mainly related to energy generation and carbohydrates catabolic processes, but leucine-supplemented group (WL) recovered the energy production. In vitro assay showed that cell proliferation, mitochondria number and oxygen consumption were higher under leucine effect than the tumour influence. Muscle proteomics results showed that the main affected cell component was mitochondria, leading to an impacted energy generation, including impairment in proteins of the tricarboxylic cycle and carbohydrates catabolic processes, which were modulated and improved by leucine treatment. Conclusion: In summary, we showed a beneficial effect of leucine upon mitochondria, providing information about the muscle glycolytic pathways used by this amino acid, where it can be associated with the preservation of morphometric parameters and consequent protection against the effects of cachexia.

Isoleucine Plays an Important Role for Maintaining Immune Function

Branched chain amino acids are the essential nutrients for humans and many animals. As functional amino acids, they play important roles in physiological functions, including immune functions. Isoleucine, as one of the branched chain amino acids, is also critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. Isoleucine can improve the immune system, including immune organs, cells and reactive substances. Recent studies have also shown that isoleucine may induce the expression of host defense peptides (i.e., β-defensins) that can regulate host innate and adaptive immunity. In addition, isoleucine administration can restore the effect of some pathogens on the health of humans and animals via increasing the expression of β-defensins. Therefore, the present review will emphatically discuss the effect of isoleucine on immunity while summarizing the relationship between branched chain amino acids and immune functions.

A leucine-rich diet modulates the mTOR cell signalling pathway in the gastrocnemius muscle under different Walker-256 tumour growth conditions

Background

The exact signalling mechanism of the mTOR complex remains a subject of constant debate, even with some evidence that amino acids participate in the same pathway as used for insulin signalling during protein synthesis. Therefore, this work conducted further study of the actions of amino acids, especially leucine, in vivo, in an experimental model of cachexia. We analysed the effects of a leucine-rich diet on the signalling pathway of protein synthesis in muscle during a tumour growth time-course.

Methods

Wistar rats were distributed into groups based on Walker-256 tumour implant and subjected to a leucine-rich diet and euthanised at three different time points following tumour development (the 7th, 14th and 21st day). We assessed the mTOR pathway key-proteins in gastrocnemius muscle, such as RAG-A-GTPase, ERK/MAP4K3, PKB/Akt, mTOR, p70S6K1, Jnk, IRS-1, STAT3, and STAT6 comparing among the experimental groups. Serum WF (proteolysis-induced factor like from Walker-256 tumour) and muscle protein synthesis and degradation were assessed.

Results

The tumour-bearing group had increased serum WF content, and the skeletal-muscle showed a reduction in IRS-1 and RAG activation, increased PKB/Akt and Erk/MAP4K3 on the 21st day, and maintenance of p70S6K1, associated with increases in muscle STAT-3 and STAT-6 levels in these tumour-bearing rats.

Conclusion

Meanwhile, the leucine-rich diet modulated key steps of the mTOR pathway by triggering the increased activation of RAG and mTOR and maintaining JNK, STAT-3 and STAT-6 levels in muscle, leading to an increased muscle protein synthesis, reducing the degradation during tumour evolution in a host, minimising the cancer-induced damages in the cachectic state.

Metabolic disorders in heart failure and cancer

In an aging population, the number of patients affected by heart failure and cancer is constantly increasing and together these two conditions account for more than 50% of all deaths worldwide. Both diseases share similar risk factors including smoking, obesity, and hypertension. Presenting symptoms may also be similar, with patients frequently complaining of dyspnea, fatigue, and anorexia. Many affected patients, especially those with more advanced heart failure or cancer, suffer also from metabolic disorders. These can lead eventually to muscle wasting, sarcopenia, and cachexia. These complications are associated with increased morbidity, a poorer quality of life, a worse prognosis and indeed they represent an independent risk factor for the advancement of the underlying disease itself. Very few therapeutic options have been established to treat these co-morbidities. For sarcopenia the only validated treatment is resistance training. Moreover, there is currently no guideline recommended therapy for the treatment of cachexia. New treatment strategies are urgently needed to prevent and treat muscle and wasting disorders in patients with chronic diseases such as cancer and chronic heart failure.

Collagen-induced arthritis as an animal model of rheumatoid cachexia

BACKGROUND

Rheumatoid arthritis is characterized by chronic polyarticular synovitis and presents systemic changes that impact quality of life, such as impaired muscle function, seen in up to 66% of the patients. This can progress to severely debilitating state known as rheumatoid cachexia-without loss of fat mass and body weight-for which there is little consensus in terms of diagnosis or treatment. This study aims to evaluate whether the collagen-induced arthritis (CIA) animal model also develops clinical and functional features characteristic of rheumatoid cachexia.

METHODS

Male DBA1/J mice were randomly divided into 2 groups: healthy animals (CO, n = 11) and CIA animals (n = 13). The clinical score and edema size, animal weight and food intake, free exploratory locomotion, grip strength, and endurance exercise performance were tested 0, 18, 35, 45, 55, and 65 days after disease induction. After euthanasia, several organs, visceral and brown fat, and muscles were dissected and weighed. Muscles were used to assess myofiber diameter. Ankle joint was used to assess arthritis severity by histological score. Statistical analysis were performed using one-way and two-way analyses of variance followed by Tukey's and Bonferroni's test or t-test of Pearson and statistical difference were assumed for a P value under 0.05.

RESULTS

The CIA had significantly higher arthritis scores and larger hind paw edema volumes than CO. The CIA had decreased endurance exercise performance total time (fatigue; 23, 22, 24, and 21% at 35, 45, 55, and 65 days, respectively), grip strength (27, 55, 63, 60, and 66% at 25, 35, 45, 55, and 65 days, respectively), free locomotion (43, 57, 59, and 66% at 35, 45, 55, and 65 days, respectively), and tibialis anterior and gastrocnemius muscle weight (25 and 24%, respectively) compared with CO. Sarcoplasmic ratios were also reduced in CIA (TA: 23 and GA: 22% less sarcoplasmic ratio), confirming the atrophy of skeletal muscle mass in these animals than in CO. Myofiber diameter was also reduced 45% in TA and 41% in GA in CIA when compared with the CO. Visceral and brown fat were lighter in CIA (54 and 39%, respectively) than CO group.

CONCLUSIONS

The CIA model is a valid experimental model for rheumatoid cachexia given that the clinical changes observed were similar to those described in patients with rheumatoid arthritis.

Leucine modulates the IPEC-J2 cell proteome associated with cell proliferation, metabolism and phagocytosis

Leucine can affect intestinal protein expressions, and improve mucosal immune function. However, little study has been conducted to determine the change of protein component by leucine treatment in intestine epithelial cells. The present study was to cover the key proteins and cell pathways that could be regulated by leucine treatment in porcine intestinal epithelial cell line (IPEC-J2) cells with the approach of proteome analysis. A total number of 3,211 proteins were identified in our approach by searching the database of Uniprot sus scrofa. Among identified proteins, there were 101 proteins expressed differently between control group and leucine group. Compared with the control group, there were 50 up-regulated proteins and 51 down-regulated proteins in leucine group. In these proteins, leucine treatment decreased the expression of some proteins including pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, E3 ubiquitin ligase, cathepsin D, caspase 3 and caspase 6, and increased the levels of some proteins, such as some eukaryotic translation initiation factors, ubiquitin carboxyl-terminal hydrolase, DNA-related RNA polymerase II, urokinase plasminogen activator, cyclin-dependent kinase inhibitor 2b, MutL homolog 1, 5-methylcytosine binding domain 4, polymerase δ, α-tubulin, syntaxin 18, Ras homolog D, actin related protein 2/3 complex and cofilin. Via the analysis of Gene Ontology and pathways, these proteins in IPEC-J2 cells were related with some physiological functions, such as protein metabolism, glycolysis, cell proliferation, apoptosis and phagocytosis. Thus, these results suggest that leucine affects gut barrier function possibly via regulating cell proliferation and apoptosis, metabolism and phagocytosis.

Elevated systemic levels of the matrix metalloproteinase inhibitor TIMP-1 correlate with clinical markers of cachexia in patients with chronic pancreatitis and pancreatic cancer

BACKGROUND

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a candidate diagnostic and prognostic biomarker for pancreatic ductal adenocarcinoma (PDAC). Here, we determined the possible association of systemic TIMP-1 levels with cachexia and jaundice, two common PDAC-associated conditions.

METHODS

Plasma TIMP-1 was measured by ELISA in patients diagnosed with PDAC (n = 36) and chronic pancreatitis (CP) (n = 25). Patients without pancreatic pathologies and known malignancies of other origin served as controls (n = 13). TIMP-1 levels in these patients were tested for asscociation with jaundice and chachexia, and furthermore correlated with cachexia-related clinical parameters such as weight loss and ferritin, parameters of lung function, hemoglobin and liver synthesis parameters.

RESULTS

TIMP-1 plasma levels were mostly higher in CP and PDAC patients with concomitant jaundice or cachexia. Elevated plasma TIMP-1 levels were also associated with clinical cachexia markers, including absolute and relative values of weight loss and lung function, as well as ferritin, hemoglobin, and cholinesterase levels. TIMP-1 levels significantly correlated with cachexia only in patients without jaundice. Jaundice also impaired the use of TIMP-1 as a prognostic marker in cancer patients. Relating to cachexia status alone, a slightly improved association of TIMP-1 levels with survival of PDAC patients was observed.

CONCLUSION

This retrospective study reports for the first time that plasma levels of TIMP-1 are associated with pancreatic lesion-induced cachexia in patients without jaundice. TIMP-1 is counterindicated as a survival marker in patients with jaundice.

Casting the net broader to confirm our imaginations: the long road to treating wasting disorders

Wasting embraces muscle and tissue wasting in sarcopenia and cachexia. This article describes recent advances in the field published in the Journal of Cachexia, Sarcopenia and Muscle concerning diagnostic tools, biomarker development, pathophysiology, and treatment. Studies discussed herein embrace those on sarcopenia and cachexia in heart failure, chronic obstructive pulmonary disease, and cancer including also animal models.

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.

Sarcopenia, cachexia, and muscle performance in heart failure: Review update 2016

Cachexia in the context of heart failure (HF) has been termed cardiac cachexia, and represents a progressive involuntary weight loss. Cachexia is mainly the result of an imbalance in the homeostasis of muscle protein synthesis and degradation due to a lower activity of protein synthesis pathways and an over-activation of protein degradation. In addition, muscle wasting leads to of impaired functional capacity, even after adjusting for clinical relevant variables in patients with HF. However, there is no sufficient therapeutic strategy in muscle wasting in HF patients and very few studies in animal models. Exercise training represents a promising intervention that can prevent or even reverse the process of muscle wasting, and worsening the muscle function and performance in HF with muscle wasting and cachexia. The pathological mechanisms and effective therapeutic approach of cardiac cachexia remain uncertain, because of the difficulty to establish animal cardiac cachexia models, thus novel animal models are warranted. Furthermore, the use of improved animal models will lead to a better understanding of the pathways that modulate muscle wasting and therapeutics of muscle wasting of cardiac cachexia.

A comparison of research into cachexia, wasting and related skeletal muscle syndromes in three chronic disease areas

INTRODUCTION

We compared the frequency of cancer, heart and lung related cachexia and cachexia-related research articles in the specialist journal, Journal of Cachexia, Sarcopenia and Muscle (JCSM) to those seen in a leading European journal in each specialist area during 2015 and 2016 to assess whether work on cachexia and related fields is relatively over or under represented in each specialist area.

RESULTS

In the dedicated journal, Journal of Cachexia, Sarcopenia and Muscle, there were 44 references related to cancer, 5 related to respiratory disease, 5 related to heart failure, and 21 related to more than one of these chronic diseases. Despite this cancer preponderance, in the European Journal of Cancer in the two publication years, there were only 5 relevant publications (0.67% of the journal output), compared to 16 (1.41%) in the European Respiratory Journal and 10 (2.19%) in the European Journal of Heart Failure.

CONCLUSIONS

There is considerable under-representation of cancer cachexia-related papers in the major European Cancer journal despite a high proportion in the dedicated cachexia journal. The under-representation is even more marked when expressed as a percentage, 0.67%, compared to 1.41% and 2.19% of the lung and heart journals respectively. These results are consistent with a worrying lack of interest in, or publication of, cachexia and related syndromes research in the cancer literature in Europe compared to its importance as a clinical syndrome. Greater interest is shown in lung and cardiology journals.

Prognostic value of malnutrition assessed by Controlling Nutritional Status score for long-term mortality in patients with acute heart failure

BACKGROUND

The prognostic value of nutritional status is poorly understood and evidence-based nutritional assessment indices are required in acute heart failure (AHF). We investigated the prognostic value of malnutrition assessed by the Controlling Nutritional Status (CONUT) score (range 0-12, higher=worse, consisting of serum albumin, cholesterol and lymphocytes) in AHF patients.

METHODS

The CONUT score was measured on admission in 635 consecutive AHF patients. The primary outcome was all-cause death.

RESULTS

Median CONUT score was 3 (interquartile range 2 to 5). During the median follow-up of 324days, CONUT score was independently associated with death (HR 1.26, 95% CI 1.11-1.42, P<0.001) after adjustment for confounders in a multivariate Cox model. The CONUT score demonstrated the best C-statistic for predicting death (0.71) among other common nutritional markers in HF. Furthermore, addition of the CONUT score to an established risk prediction model from the Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure study significantly increased the C-statistic from 0.75 to 0.77 (P=0.02). The net reclassification improvement afforded by CONUT score was 21% for all-cause death, 27% for survival and 49% overall (P<0.001).

CONCLUSION

Malnutrition assessed by the CONUT score on admission was an independent determinant of long-term death in AHF, and its prognostic value outweighed that of other nutritional indices. Moreover, addition of the score to the existing risk prediction model significantly increased the predictive ability for death, indicating beneficial clinical application of the CONUT score in AHF patients.

Nutritional leucine supplementation attenuates cardiac failure in tumour-bearing cachectic animals

BACKGROUND

The condition known as cachexia presents in most patients with malignant tumours, leading to a poor quality of life and premature death. Although the cancer-cachexia state primarily affects skeletal muscle, possible damage in the cardiac muscle remains to be better characterized and elucidated. Leucine, which is a branched chain amino acid, is very useful for preserving lean body mass. Thus, this amino acid has been studied as a coadjuvant therapy in cachectic cancer patients, but whether this treatment attenuates the effects of cachexia and improves cardiac function remains poorly understood. Therefore, using an experimental cancer-cachexia model, we evaluated whether leucine supplementation ameliorates cachexia in the heart.

METHODS

Male Wistar rats were fed either a leucine-rich or a normoprotein diet and implanted or not with subcutaneous Walker-256 carcinoma. During the cachectic stage (approximately 21 days after tumour implantation), when the tumour mass was greater than 10% of body weight, the rats were subjected to an electrocardiogram analysis to evaluate the heart rate, QT-c, and T wave amplitude. The myocardial tissues were assayed for proteolytic enzymes (chymotrypsin, alkaline phosphatase, cathepsin, and calpain), cardiomyopathy biomarkers (myeloperoxidase, tissue inhibitor of metalloproteinases, and total plasminogen activator inhibitor 1), and caspase-8, -9, -3, and -7 activity.

RESULTS

Both groups of tumour-bearing rats, especially the untreated group, had electrocardiography alterations that were suggestive of ischemia, dilated cardiomyopathy, and sudden death risk. Additionally, the rats in the untreated tumour-bearing group but not their leucine-supplemented littermates exhibited remarkable increases in chymotrypsin activity and all three heart failure biomarkers analysed, including an increase in caspase-3 and -7 activity.

CONCLUSIONS

Our data suggest that a leucine-rich diet could modulate heart damage, cardiomyocyte proteolysis, and apoptosis driven by cancer-cachexia. Further studies must be conducted to elucidate leucine's mechanisms of action, which potentially includes the modulation of the heart's inflammatory process.

Publication trends in cachexia and sarcopenia in elderly heart failure patients

The loss of skeletal mass - sarcopenia and cachexia - is considered to be a major contributor to morbidity and mortality in chronic heart failure (CHF). Unfortunately, sarcopenia is generally considered to be a geriatric syndrome, but not necessarily seen as a comorbidity in CHF, even though it has a wide range of adverse health outcomes. While there were 15,574 publication with the title word "heart failure" in PubMed in the 5‑year period from 1 June 2011 to 31 May 2016, only 22 or 71 publications were found with the search combination "sarcopenia" or "cachexia" (title word) and "heart failure" (all fields), respectively. This shows very clearly that loss of muscle quality and function due to heart failure is still an underappreciated problem in the medical field.

Leucine-rich diet alters the 1H-NMR based metabolomic profile without changing the Walker-256 tumour mass in rats

Background

Cachexia is one of the most important causes of cancer-related death. Supplementation with branched-chain amino acids, particularly leucine, has been used to minimise loss of muscle tissue, although few studies have examined the effect of this type of nutritional supplementation on the metabolism of the tumour-bearing host. Therefore, the present study evaluated whether a leucine-rich diet affects metabolomic derangements in serum and tumour tissues in tumour-bearing Walker-256 rats (providing an experimental model of cachexia).

Methods

After 21 days feeding Wistar female rats a leucine-rich diet, distributed in L-leucine and LW-leucine Walker-256 tumour-bearing groups, we examined the metabolomic profile of serum and tumour tissue samples and compared them with samples from tumour-bearing rats fed a normal protein diet (C – control; W – tumour-bearing groups). We utilised ¹H-NMR as a means to study the serum and tumour metabolomic profile, tumour proliferation and tumour protein synthesis pathway.

Results

Among the 58 serum metabolites examined, we found that 12 were altered in the tumour-bearing group, reflecting an increase in activity of some metabolic pathways related to energy production, which diverted many nutrients toward tumour growth. Despite displaying increased tumour cell activity (i.e., higher Ki-67 and mTOR expression), there were no differences in tumour mass associated with changes in 23 metabolites (resulting from valine, leucine and isoleucine synthesis and degradation, and from the synthesis and degradation of ketone bodies) in the leucine-tumour group. This result suggests that the majority of nutrients were used for host maintenance.

Conclusion

A leucine rich-diet, largely used to prevent skeletal muscle loss, did not affect Walker 256 tumour growth and led to metabolomic alterations that may partially explain the positive effects of leucine for the whole tumour-bearing host.

Branched chain amino acid metabolic reprogramming in heart failure

Metabolic remodeling is a hall-mark of cardiac maturation and pathology. The switch of substrate utilization from glucose to fatty acid is observed during post-natal maturation period in developing heart, but the process is reversed from fatty acids to glucose in the failing hearts across different clinic and experimental models. Majority of the current investigations have been focusing on the regulatory mechanism and functional impact of this metabolic reprogramming involving fatty acids and carbohydrates. Recent progress in metabolomics and transcriptomic analysis, however, revealed another significant remodeled metabolic branch associated with cardiac development and disease, i.e. Branched-Chain Amino Acid (BCAA) catabolism. These findings have established BCAA catabolic deficiency as a novel metabolic feature in failing hearts with potentially significant impact on the progression of pathological remodeling and dysfunction. In this review, we will evaluate the current evidence and potential implication of these discoveries in the context of heart diseases and novel therapies. This article is part of a Special Issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck & Jan F.C. Glatz.

The Walker 256 Breast Cancer Cell- Induced Bone Pain Model in Rats

The majority of patients with terminal breast cancer show signs of bone metastasis, the most common cause of pain in cancer. Clinically available drug treatment options for the relief of cancer-associated bone pain are limited due to either inadequate pain relief and/or dose-limiting side-effects. One of the major hurdles in understanding the mechanism by which breast cancer causes pain after metastasis to the bones is the lack of suitable preclinical models. Until the late twentieth century, all animal models of cancer induced bone pain involved systemic injection of cancer cells into animals, which caused severe deterioration of animal health due to widespread metastasis. In this mini-review we have discussed details of a recently developed and highly efficient preclinical model of breast cancer induced bone pain: Walker 256 cancer cell- induced bone pain in rats. The model involves direct localized injection of cancer cells into a single tibia in rats, which avoids widespread metastasis of cancer cells and hence animals maintain good health throughout the experimental period. This model closely mimics the human pathophysiology of breast cancer induced bone pain and has great potential to aid in the process of drug discovery for treating this intractable pain condition.