Cachexia is a highly complex syndrome identified by metabolic, hormonal and cytokine-related abnormalities, but can be shortly characterized as accelerated skeletal muscle and adipose tissue loss in the context of a chronic inflammatory response. Cachexia is a debilitating complication of several diseases such as AIDS, sepsis, diabetes, renal failure, burn injury and cancer. Cachexia is responsible for 25-30% of cancer patient deaths. One of the most obvious outcomes of cancer cachexia is the redistribution of the total protein content, namely the depletion of skeletal muscle protein levels and increase in the acute phase response protein levels as a response to tissue injury. Although the plasticity of muscle mass and utility of skeletal muscle as a protein source are known facts, there have not been many studies concerning the mechanism of conversion of skeletal muscle proteins to other protein forms, for which the organism has greater need. IL-6 and activation of the acute phase response have been linked to cancer cachexia. However, IL-6 is generally not thought to signal directly on skeletal muscle and to date no studies have manipulated the STAT3 pathway for regulating skeletal muscle mass. Our data demonstrate direct action of IL-6 on activation of the STAT3 and acute phase response pathway at the skeletal muscle. In addition, our observations that STAT3 is broadly activated in cachexia and that STAT3 activation is sufficient and necesssary to induce muscle wasting are also novel. Thus, these studies define a new pathway leading to muscle wasting, which can be a potential target for reversing muscle wasting in cancer cachexia. Successful inhibition of skeletal muscle wasting and other metabolic derangements of cachexia will increase quality of life and survival of a significant fraction of cancer patients.

Thesis (Ph. D.)--University of Sydney, 2009. / Title from title screen (viewed Aug. 11, 2009) Includes tables and questionnaires. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Surgery, Faculty of Medicine. Degree awarded 2009 ; thesis submitted 2008. Includes bibliographical references. Also available in print form.

Thesis (M.Sc.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Computing Science. Title from pdf file main screen (viewed on June 13, 2010). Includes bibliographical references.

Cachexia occurs commonly and is a significant cause of morbidity and up to 20% mortality in patients with cancer. Loss of muscle mass occurs as part of the cachexia wasting process and low muscle mass is a key element of the most recent consensus cachexia definition. Measuring muscle mass and changes in skeletal muscle is important to phenotype cachectic individuals and to monitor response to anti-cachectic treatments. This thesis investigates minimally invasive or burdensome methods of measuring muscle mass and muscle protein kinetics for use in a clinical or research setting. Quantification of muscle area on routine diagnostic cross-sectional imaging offers a novel and relatively non-invasive method of assessing both regional (and by extrapolation) whole body muscle mass. The need for such a direct measurement of muscle mass was demonstrated by showing that simple anthropometric formulae are unable to predict muscularity accurately (within 25%) when compared with estimates derived from patients diagnostic CT scans. It may be that qualitative changes in muscle may be more sensitive indices of the wasting process rather than qualitative change. Myosteatosis (infiltration of muscle by fat) is known to occur in both cachexia and age related sarcopenia and can be quantified using the Hounsfield spectrum observed on routine diagnostic CT scans. However, not all patients undergo routine CT scanning and there is a need for a biomarker derived from urine or blood. Consequently, cross sectional imaging was used to phenotype patients in a proteomic analysis of urine with the aim of identifying protein or peptide biomarkers associated with myosteatosis in cancer cachexia. A biomarker model for myosteatosis was developed with good sensitivity (97%) but poor specificity (71%). Many of the potential protein / peptide markers identified had poor associations with known mechanisms of muscle wasting and further study of the identified peptides in an extended cohort would help determine the validity of the present findings. However, two proteins with potential roles in muscle repair or neuromuscular function (Agarin and Cathepsin C) were identified and these may warrant targeted investigation with evaluation against sequential measures of muscle mass to determine their value in defining muscle loss over time. As different regional measures of muscularity are available, trunk (L3 CT) and limb muscle (quadriceps MRI) cross sectional measurements were compared with functional assessments to determine the optimal site for measurement. Neither measure proved superior to the other but appeared to reflect different aspects of function. Quadriceps muscle area correlated with quadriceps strength and power whilst truncal muscle area correlated more with complex movements such as the timed-up-and-go test. Changes in regional muscle area in patients with upper gastrointestinal cancer were assessed by upper and lower limb MRI before and after surgery and by L3 CT cross sectional area before and after neo-adjuvant chemotherapy. No change in limb muscularity was seen at 220 days post operatively compared with pre-op measurements. During neo-adjuvant chemotherapy a significant loss of truncal muscle occurred in the absence of significant weight loss suggesting that sequential cross sectional imaging is capable of detecting changes in body composition that may not be apparent clinically. Whilst sequential scans may document changes in muscularity, they do not describe the underlying levels of muscle synthesis or degradation that may regulate muscle volume. The final section of this thesis describes the development of a novel tracer method to measure skeletal muscle synthesis and its application in a study of patients with cancer and healthy volunteers. This novel method was able to measure skeletal muscle fractional synthetic rate (FSR) over a longer time-period than previous methods (weeks rather than hours) and reduced the burden on the patient by the use of a single oral tracer dose and single muscle biopsy. Comparison of synthesis rates in quadriceps and rectus abdominis showed higher rates in quadriceps, 0.067% per hour vs 0.058% per hour respectively. Despite a net loss of muscle as measured by serial CT scans, skeletal muscle FSR appeared to be marginally increased in weight losing patients with cancer compared with weight stable patients and healthy controls. When FSR was combined with measures of muscle mass it was demonstrated that only small differences between synthesis and degradation are required to see the levels of muscle wasting seen in patients with cancer. In summary, routine cross sectional imaging provides a useful and unique measure of muscularity that is associated with function in patients with cancer Sequential scans can provide additional information about changes in body composition even in the absence of weight loss. There are significant regional variations in both muscle wasting and skeletal muscle fractional synthetic rate. The combination of sequential estimates of muscle mass from diagnostic CT scans along with estimates of FSR allow assessment of the contribution of altered synthesis and degradation to muscle loss. In patients with upper GI cancer it would appear that increased degradation may be more important that altered synthesis. The relative change in either process to account for absolute loss of muscle mass is small. Such findings have implications for the targeted therapy of muscle wasting in cancer patients.

The American Cancer Society predicted that 230,480 women would be diagnosed with, and 39,520 women would die from breast cancer (BC) in the United States in 2011. While the incidence of female BC has been decreasing, BC remains the second leading cause of cancer death among women in the United States. Cancer cachexia, the cancer-related loss of muscle, affects up to 25% of BC patients and is associated with poor prognosis and decreased quality of life. Alterations to the dystrophin glycoprotein complex (DGC), a transmembrane, multi-subunit protein complex with structural and signaling roles, have been reported in mammary tumors of BC patients and skeletal muscles of cachectic cancer patients. However, this complex is most frequently studied for its role in Duchenne muscular dystrophy (DMD), a severe, progressive muscle wasting disease. Despite the similar alterations reported in these diseases, it is unclear whether alterations in the DGC in one tissue can impact the progression of disease in another. Purpose: The purpose of the studies described in this dissertation was to identify differences in body composition, energy expenditure and plasma cytokine content between the C57BL/10ScSn-Dmdmdx/J (mdx) mouse model of DMD and C57BL/10ScSnJ (BL/10) control mice and to determine whether systemic alteration of the DGC (as observed in the mdx mouse) alters the growth of E0771 murine mammary tumors. Results: There were differences in body composition and plasma cytokine profiles between mdx and BL/10 mice. We also found that, relative to controls, the tumor–induced increase in cytokines that promote invasion and metastasis was not as severe in mdx mice. Conclusions: This study revealed several differences between mdx and BL/10 mice and provides support for the suggestion that the mdx mouse may not be an accurate model of DMD. In addition, the improved cytokine profile of tumor-bearing mdx mice suggests that the acute phase of DMD may be protective against BC invasion and metastasis. Further research should confirm this effect and determine whether alterations in the DGC of the mdx mouse are directly or indirectly responsible. / Ph. D.

Cachexia affects up to two thirds of all cancer patients with progressive disease. It is a syndrome characterised by weight-loss, anorexia, fatigue, asthenia, peripheral oedema, and is responsible for around 20% of cancer deaths. Cachectic patients suffer loss of both muscle mass and adipose tissue (with comparative sparing of visceral protein) and the lean tissue loss appears resistant to nutritional support. Progress in the treatment of cancer cachexia has been hampered due to poor understanding of the molecular mechanisms of skeletal muscle wasting in humans (rather than preclinical models) combined with a lack of accurate phenotyping particularly with respect to loss of skeletal muscle mass and function. The aim of the present thesis was to improve the knowledge and tools available for early intervention studies. The thesis focused on skeletal muscle as a key compartment in cancer cachexia. The experimental model was patients with upper gastrointestinal (UGI) cancer undergoing potentially curative surgery due to the associated higher incidence of cachexia along with the ability to access tissue biopsies. The thesis broadly divides into two sections. Part I reports a series of cancer cachexia biomarker discovery studies based on direct biopsy and analysis of human skeletal muscle. Part II focused on assessment and phenotyping of skeletal muscle mass and function in cachectic UGI cancer patients. In addition, the feasibility of longitudinal clinical studies that utilise such methodology is reported. Intramuscular β-dystroglycan protein content (assessed using Western blot) was identified as a potential biomarker of cancer cachexia whereas changes in the structural elements of muscle (myosin heavy chain or dystrophin) appeared to be survival biomarkers. Using transcriptomics, an 82-gene signature was demonstrated to correlate with weight-loss. Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to examine the genes from this signature that were most upregulated. The exercise activated genes, CAMk2β and TIE1, correlated positively with weight-loss across different muscle groups (Rectus abdominis, Vastus lateralis, Diaphragma) indicating that cachexia was not simply due to inactivity and suggesting that these genes could be used as biomarkers of cachexia. None of the biomarkers discovered were consistent with pre-clinical models and therefore require further study before progressing to a validation programme. Electron microscopy of muscle biopsies demonstrated that the number and size of intramyocellular lipid droplets was increased in the presence of cancer and increases further with weightloss/ loss of adipose mass in other body compartments. The specific mechanisms and drivers of this phenomenon remain to be elucidated, but could relate to enhanced lipolysis or mitochondrial dysfunction in skeletal muscle as well as influencing muscle mechanical quality. Physiological assessment of patients with cancer cachexia established the negative impact that cachexia can have on muscle mass, function, muscle quality and quality of life, but demonstrated that the degree of impairment varies with sex and between muscle groups. Furthermore, the challenge of longitudinal studies in this patient group where frailty and clinical deterioration limit repeated assessments was highlighted. Such issues emphasise the need for a dual approach to the classification of cancer cachexia: if molecular markers prove difficult to discover or validate, then more specific and robust physiological indices of skeletal muscle mass and function may be the more important route to improve clinical trial design and cachexia classification.

Orientador: Gisele Fabrino Machado / Resumo: Em cães com leishmaniose visceral (LVC), é comum a emaciação corporal crônica, a qual pode caracterizar negligência. Objetivou-se verificar as condições corporais e quantificar gordura de medula óssea (GMO), buscando estabelecer parâmetros que possam caracterizar casos de negligência em cães com LVC. Foram utilizados 39 cães naturalmente infectados e com diagnóstico de LVC, provenientes de Araçatuba/SP. Os animais foram divididos em três grupos: multissintomáticos (MULTI; n=25); oligo/assintomáticos (OLIGO; n=14); o grupo controle (CONT; n=11) foi constituído de cães com sorologia e PCR negativos para LVC. Foi determinado o score corporal e o índice de massa corporal (IMC) por meio da divisão do peso do animal (kg) pelo comprimento da coluna (m). A medula óssea foi colhida de ossos longos (fêmur e úmero), homogeneizada e separada em duas alíquotas para mensuração da gordura, por meio da porcentagem (método Soxhlet) e gordura sobrenadante (mm em tubo de 15mL). O grupo MULTI apresentou score corporal (1,88) inferior ao OLIGO (2,93) e CONT (3,27). O IMC do MULTI (18,33) foi menor que o do OLIGO (28,59). O IMC do CONT foi de 22,92, sem diferença (p<0,05) em relação aos animais positivos. A quantidade de GMO do MULTI foi de 1,6mm e 21,64%, valores inferiores e significativamente diferentes (p<0,05) aos do OLIGO (4mm; 58,47%) e CONT (5,5mm; 64,1%). Portanto, a avaliação macroscópica da GMO e sua quantificação é eficaz na determinação de condições corporais na LVC crônica, podendo s... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In dogs with visceral leishmaniasis (CVL), chronic body wasting is common, which may characterize neglect. The objective was to verify body conditions and quantify bone marrow fat (BMF), seeking to establish parameters that can characterize cases of neglect in dogs with CVL. 39 naturally infected dogs with a diagnosis of leishmaniasis from Araçatuba/SP were used. The animals were divided into three groups: multisymptomatic (MULTI; n=25); oligo/asymptomatic (OLIGO; n=14); the control group (CONT; n=11) consisted of dogs with negative serology and PCR for CVL. Body score and body mass index (BMI) were determined by dividing the weight of the animal (kg) by the length of the column (m). The bone marrow was harvested from long bones (femur and humerus), homogenized and separated into two aliquots to measure the fat, by means of the percentage (Soxhlet method) and supernatant fat (mm in 15mL tube). The group MULTI presented lower body score (1.88) than OLIGO (2.93) and CONT (3.27). The BMI of MULTI (18.33) was lower than that of OLIGO (28.59). The BMI of CONT was 22.92, with no difference (p<0.05) in relation to the animals in CVL groups. The amount of BMF in MULTI was 1.6mm and 21.64%, lower and significantly different values (p<0.05) than those observed in OLIGO (4mm; 58.47%) and CONT (5.5mm, 64.1%). Therefore, the gross evaluation of bone marrow fat and its quantification is effective in determining body conditions in chronic CVL and may be a parameter used in cases of neglect ... (Complete abstract click electronic access below) / Doutor

Diss. (sammanfattning) Göteborg : Göteborgs universitet , 2008. / Härtill 5 uppsatser.

Cigarette smoking (CS) represents the main causative agent underlying development and progress of COPD. Recently, involvement of CS in the pathogenesis of COPDassociated muscle abnormalities is becoming increasingly evident. Nevertheless, involved triggers and underlying mechanisms remain largely unknown. This study was conceived in order to examine effects of cigarette smoke exposure on skeletal muscle morphology, vascular supply and function. For this purpose, we have specifically designed murine COPD/emphysema model and gastrocnemius muscle was examined, while in vitro experiments were conducted using murine C2C12 skeletal muscle myocytes. In addition to the mild emphysematous changes present in the lungs of CS-exposed mice, our results demonstrated evident signs of muscle atrophy reflected by decreased fiber cross-sectional area, profound fiber size variation and reduced body mass. Furthermore, we have observed impairment in terminal myogenesis and lower number of myonuclei in skeletal muscles of CS-exposed animals despite evident activation of muscle repair process. Additionally, our results demonstrate capillary rarefaction in skeletal muscles of CS-exposed animals which was associated with deregulation of hypoxia-angiogenesis signaling, reduced levels of angiogenic factors such as HIF1-α and VEGF and enhanced expression of VHL and its partner proteins PHD2 and Ube2D1. The results of our in-vitro experiments demonstrated that VHL and its ubiquitination machinery can be synergistically regulated by TNF and hypoxia consequentially impairing angiogenic potential of skeletal muscle myocytes. Finally, we have shown that CS elicits chronic ER stress in murine skeletal muscles which is associated with activation of ERAD and apoptotic pathways as mirrored by elevated expression of Usp19, caspase 12 and caspase 3 in skeletal muscles of CSexposed animals. Moreover, molecular and morphological alterations in CS-exposed mice resulted in impairment of muscle function as reflected by their impaired exercise capacity. Taken together, from our results it is evident that cigarette smoke exposure elicits set of morphological, vascular and functional changes highly resembling those observed in COPD. Additionally, CS induces wide range of molecular alterations and signaling pathway deregulations suggesting profound effects of cigarette smoke exposure on skeletal muscle cell homeostasis.

Cachexia is a multifactorial metabolic wasting syndrome that affects a large percentage of cancer patients and results in the involuntary loss of skeletal muscle and adipose tissue. The consequences of this condition include metabolic imbalances and fatigue, which are strongly associated with poor prognosis. While the specific mechanism for skeletal muscle wasting is still undefined, LIF secreted by C26 colon carcinoma cells has recently be found to induce atrophy in treated myotubes. The purpose of this study is to determine the necessity of LIF for inducing atrophy in mouse myotubes by producing a knockout of Lif in C26 cells using CRIPSR-Cas9. Media was collected from these cells and used to treat myotubes. Measurements of myotube diameters were made and atrophy was compared between myotubes that received medium from C26 and C26Lif-/- cells. A dosage of recombinant mouse LIF was also added to LIF-deficient medium in order to determine if LIF alone was sufficient to induce atrophy. At study endpoint, myotubes that were treated with media taken from C26 cells showed significant signs of atrophy compared to myotubes that were treated C26Lif-/- media. LIF was also shown to be sufficient to induce myotube atrophy on its own, with atrophy being rescued in myotubes that received a dosage of LIF added to C26Lif-/- media. These results demonstrate that LIF is required for atrophy to be induced in mouse myotubes treated with media taken from cancer cells, and can do so independent of other secreted factors.