The association between preoperative body composition and aerobic fitness in patients scheduled for colorectal surgery.

AIM: Although cardiopulmonary exercise testing (CPET) is considered the gold standard, a preoperative abdominal CT scan might also provide information concerning preoperative aerobic fitness for risk assessment. This study aimed to investigate the association between preoperative CT-scan-derived body composition variables and preoperative CPET variables of aerobic fitness in colorectal surgery. METHOD: In this retrospective cohort study, CT images at level L3 were analysed for skeletal muscle mass, skeletal muscle radiation attenuation, visceral adipose tissue (VAT) mass and subcutaneous adipose tissue mass. Regression analyses were performed to investigate the relation between CT-scan-derived body composition variables, CPET-derived aerobic fitness and other preoperative patient-related variables. Logistic regression analysis was performed to predict a preoperative anaerobic threshold (AT) ≤ 11.1 ml/kg/min as cut-off for having a high risk for postoperative complications. RESULTS: Data from 78 patients (45 men; mean [SD] age 74.5 [6.4 years]) were analysed. A correlation coefficient of 0.55 was observed between absolute AT and skeletal muscle mass index. Absolute AT (R2 of 51.1%) was lower in patients with a lower skeletal muscle mass index, together with higher age, lower body mass and higher American Society of Anesthesiologists (ASA) score. Higher ASA score (odds ratio 5.64; P = 0.033) and higher VAT mass (odds ratio 1.02; P = 0.036) were associated with an increased risk of an AT ≤ 11.1 ml/kg/min. CONCLUSION: Body composition variables from the preoperative CT scan were moderately associated with preoperative CPET-derived aerobic fitness. Higher ASA score and higher VAT mass were associated with an increased risk of an AT ≤ 11.1 ml/kg/min.

The reproducibility of skeletal muscle signal intensity on routine magnetic resonance imaging in Crohn's disease.

BACKGROUND AND AIM: Myosteatosis is a prognostic factor in cancer and liver cirrhosis. It can be determined noninvasively using computed tomography or, as shown recently, by magnetic resonance (MR) imaging. The primary aim was to analyze the reproducibility of skeletal muscle signal intensity on routine MR-enterographies, as indicator of myosteatosis, in Crohn's disease (CD) and to explore the association between skeletal muscle signal intensity at diagnosis with time to intestinal resection. METHODS: CD patients undergoing MR-enterography within 6 months from diagnosis and having a maximum of 5 years follow-up were included. Skeletal muscle signal intensity was analyzed on T1-weighted fat-saturated post-contrast images. Intra-observer and inter-observer reproducibilities were assessed by intra-class correlation coefficient and Cohen's kappa. Intra-observer and inter-observer variabilities were determined by Pearson correlation coefficient and displayed by Bland-Altman plots. Time to intestinal resection was studied by Kaplan-Meier analysis. RESULTS: Median time between diagnosis and MR-enterography was 5 weeks (inter-quartile range 1-9) in 35 CD patients. Skeletal muscle signal intensity showed good intra-class correlation and substantial agreement (for intra-observer, intraclass correlation coefficient = 0.948, κ = 0.677; and inter-observer reproducibility, intraclass correlation coefficient = 0.858, κ = 0.622). Resection free survival was shorter in the low skeletal muscle signal intensity group (P = 0.037). CONCLUSION: Skeletal muscle signal intensity on routine MR-enterographies is reproducible and was associated with unfavorable disease outcome, indicating potential clinical relevance.

Low thoracic muscle radiation attenuation is associated with postoperative pneumonia following partial hepatectomy for colorectal metastasis.

BACKGROUND: Low skeletal muscle radiation attenuation (SM-RA) is indicative of myosteatosis and diminished muscle function. It is predictive of poor outcome following oncological surgery in several cancer types. Postoperative pneumonia is a known risk factor for increased postoperative mortality. We hypothesized that low SM-RA of the respiratory muscles at the 4th thoracic-vertebra (T4) is associated with postoperative pneumonia following liver surgery. METHODS: Postoperative pneumonia was identified using prospective infection control data. Computed tomography body composition analysis was performed at the L3-and T4 level to determine SM-RA. Body composition variables were corrected for confounders and related to postoperative pneumonia and admission time by multivariable logistic regression. RESULTS: Body composition analysis of 180 patients was performed. Twenty-one patients developed postoperative pneumonia (11.6%). Multivariable analysis showed that low T4 SM-RA as well as low L3 SM-RA were significantly associated with postoperative pneumonia (OR 3.65, 95% CI 1.41-9.49, p < 0.01) and (OR 3.22, 95% CI 1.20-8.61, p = 0.02, respectively). CONCLUSION: Low SM-RA at either the L3-or T4-level is associated with a higher risk of postoperative pneumonia following CLRM resection.

A novel human cell culture model to study visceral smooth muscle phenotypic modulation in health and disease.

Adaptation of the smooth muscle cell (SMC) phenotype is essential for homeostasis and is often involved in pathologies of visceral organs (e.g., uterus, bladder, gastrointestinal tract). In vitro studies of the behavior of visceral SMCs under (patho)-physiological conditions are hampered by a spontaneous, uncontrolled phenotypic modulation of visceral SMCs under regular tissue culture conditions. We aimed to develop a new visceral SMC culture model that allows controlled phenotypic modulation. Human uterine SMCs [ULTR and telomerase-immortalized human myometrial cells (hTERT-HM)] were grown to confluency and kept for up to 6 days on regular tissue culture surfaces or basement membrane (BM) matrix-coated surfaces in the presence of 0-10% serum. mRNA and protein expression and localization of SMC-specific phenotype markers and their transcriptional regulators were investigated by quantitative PCR, Western blotting, and immunofluorescence. Maintaining visceral SMCs confluent for 6 days increased α-smooth muscle actin (1.9-fold) and smooth muscle protein 22-α (3.1-fold), whereas smooth muscle myosin heavy chain was only slightly upregulated (1.3-fold). Culturing on a BM matrix-coated surface further increased these proteins and also markedly promoted mRNA expression of γ-smooth muscle actin (15.0-fold), smoothelin (3.5-fold), h-caldesmon (5.2-fold), serum response factor (7.6-fold), and myocardin (8.1-fold). Whereas additional serum deprivation only minimally affected contractile markers, platelet-derived growth factor-BB and transforming growth factor ß1 consistently reduced versus increased their expression. In conclusion, we present a simple and reproducible visceral SMC culture system that allows controlled phenotypic modulation toward both the synthetic and the contractile phenotype. This may greatly facilitate the identification of factors that drive visceral SMC phenotypic changes in health and disease.

Myosteatosis predicts survival after surgery for periampullary cancer: a novel method using MRI.

BACKGROUND: Myosteatosis, characterized by inter- and intramyocellular fat deposition, is strongly related to poor overall survival after surgery for periampullary cancer. It is commonly assessed by calculating the muscle radiation attenuation on computed tomography (CT) scans. However, since magnetic resonance imaging (MRI) is replacing CT in routine diagnostic work-up, developing methods based on MRI is important. We developed a new method using MRI-muscle signal intensity to assess myosteatosis and compared it with CT-muscle radiation attenuation. METHODS: Patients were selected from a prospective cohort of 236 surgical patients with periampullary cancer. The MRI-muscle signal intensity and CT-muscle radiation attenuation were assessed at the level of the third lumbar vertebra and related to survival. RESULTS: Forty-seven patients were included in the study. Inter-observer variability for MRI assessment was low (R2 = 0.94). MRI-muscle signal intensity was associated with short survival: median survival 9.8 (95%-CI: 1.5-18.1) vs. 18.2 (95%-CI: 10.7-25.8) months for high vs. low intensity, respectively (p = 0.038). Similar results were found for CT-muscle radiation attenuation (low vs. high radiation attenuation: 10.8 (95%-CI: 8.5-13.1) vs. 15.9 (95%-CI: 10.2-21.7) months, respectively; p = 0.046). MRI-signal intensity correlated negatively with CT-radiation attenuation (r=-0.614, p < 0.001). CONCLUSIONS: Myosteatosis may be adequately assessed using either MRI-muscle signal intensity or CT-muscle radiation attenuation.

ERAS: Improving outcome in the cachectic HPB patient.

The enhanced recovery after surgery (ERAS) program has reduced postoperative morbidity and duration of hospital stay but not mortality in patients undergoing hepatopancreatobiliary (HPB) surgery. Many HPB patients suffer from cancer cachexia, a syndrome of severe weight and muscle loss. This may affect outcomes of HPB surgery even within an ERAS program. A tailored ERAS approach may be essential in further improving outcome in this vulnerable patient category.

External validation of a deep learning model for automatic segmentation of skeletal muscle and adipose tissue on abdominal computed tomography images.

BACKGROUND: Body composition assessment using computed tomography (CT) images at the L3-level is increasingly applied in cancer research. Robust high-throughput automated segmentation is key to assess large patient cohorts and to support implementation of body composition analysis into routine clinical practice. We trained and externally validated a deep learning neural network (DLNN) to automatically segment L3-CT images. METHODS: Expert-drawn segmentations of visceral and subcutaneous adipose tissue (VAT/SAT) and skeletal muscle (SM) of L3-CT-images of 3,187 patients undergoing abdominal surgery were used to train a DLNN. The external validation cohort was comprised of 2,535 patients with abdominal cancer. DLNN performance was evaluated with (geometric) Dice Similarity (DS) and Lin's Concordance Correlation Coefficient. RESULTS: There was a strong concordance between automatic and manual segmentations with median DS for SM, VAT, and SAT of 0.97 (interquartile range, IQR: 0.95-0.98), 0.98 (IQR: 0.95-0.98), and 0.95 (IQR: 0.92-0.97), respectively. Concordance correlations were excellent: SM 0.964 (0.959-0.968), VAT 0.998 (0.998-0.998), and SAT 0.992 (0.991-0.993). Bland-Altman metrics indicated only small and clinically insignificant systematic offsets; SM radiodensity: 0.23 hounsfield units (0.5%), SM: 1.26 cm2.m-2 (2.8%), VAT: -1.02 cm2.m-2 (1.7%), and SAT: 3.24 cm2.m-2 (4.6%). CONCLUSION: A robustly-performing and independently externally validated DLNN for automated body composition analysis was developed. ADVANCES IN KNOWLEDGE: CT-based body composition analysis is highly prognostic for long-term overall survival in oncology. This DLNN was succesfully trained and externally validated on several large patient cohorts and will therefore enable large scale population studies and implementation of body composition analysis into clinical practice.

Inflammation-associated intramyocellular lipid alterations in human pancreatic cancer cachexia.

BACKGROUND: Cancer cachexia is a multifactorial metabolic syndrome characterized by systemic inflammation and ongoing skeletal muscle loss resulting in weakness, poor quality of life, and decreased survival. Whereas lipid accumulation in skeletal muscle is associated with cancer cachexia as well as the prognosis of cancer patients, surprisingly little is known about the nature of the lipids that accumulate in the muscle during cachexia, and whether this is related to inflammation. We aimed to identify the types and distributions of intramyocellular lipids in patients with and without cancer cachexia. METHODS: Rectus abdominis muscle biopsies were collected during surgery of patients with pancreatic ductal adenocarcinoma (n = 10 without cachexia, n = 20 cachectic without inflammation (CRP < 10 mg/L), n = 10 cachectic with inflammation (CRP ≥ 10 mg/L). L3-CT scans were analysed to assess body composition based on validated thresholds in Hounsfield units (HU). Muscle sections were stained with Oil-Red O and H&E to assess general lipid accumulation and atrophy. Untargeted lipidomic analyses were performed on laser-microdissected myotubes using LC-MS/MS. The spatial distribution of intramyocellular lipids with differential abundance between groups was visualized by mass-spectrometry imaging. Genes coding for inflammation markers and enzymes involved in de novo ceramide synthesis were studied by qPCR. RESULTS: Muscle radiation attenuation was lower in cachectic patients with inflammation (median 24.3 [18.6-30.8] HU) as compared with those without inflammation (34.2 [29.3-38.7] HU, P = 0.033) or no cachexia (37.4 [33.9-42.9] HU, P = 0.012). Accordingly, intramyocellular lipid content was lower in non-cachectic patients (1.9 [1.6-2.1]%) as compared with those with cachexia with inflammation (5.5 [4.5-7.3]%, P = 0.002) or without inflammation (4.8 [2.6-6.0]%, P = 0.017). Intramyocellular lipid accumulation was associated with both local IL-6 mRNA levels (rs = 0.57, P = 0.015) and systemic CRP levels (rs = 0.49, P = 0.024). Compared with non-cachectic subjects, cachectic patients had a higher relative abundance of intramyocellular glycerophospholipids and a lower relative abundance of glycerolipids. Furthermore, increases in several intramyocellular lipids such as SM(d36:1), PC(34:1), and TG(48:1) were found in cachectic patients with inflammation and correlated with specific cachexia features. Altered intramyocellular lipid species such as PC(34:1), LPC(18:2), and TG(48:1) showed an uneven distribution in muscle sections of cachectic and non-cachectic patients, with areas featuring abundance of these lipids next to areas almost devoid of them. CONCLUSIONS: Intramyocellular lipid accumulation in patients with cachexia is associated with both local and systemic inflammation, and characterized by changes in defined lipid species such as glycerolipids and glycerophospholipids.

Identifying radiomics signatures in body composition imaging for the prediction of outcome following pancreatic cancer resection.

Background: Computerized radiological image analysis (radiomics) enables the investigation of image-derived phenotypes by extracting large numbers of quantitative features. We hypothesized that radiomics features may contain prognostic information that enhances conventional body composition analysis. We aimed to investigate whether body composition-associated radiomics features hold additional value over conventional body composition analysis and clinical patient characteristics used to predict survival of pancreatic ductal adenocarcinoma (PDAC) patients. Methods: Computed tomography images of 304 patients undergoing elective pancreatic cancer resection were analysed. 2D radiomics features were extracted from skeletal muscle and subcutaneous and visceral adipose tissue (SAT and VAT) compartments from a single slice at the third lumbar vertebra. The study population was randomly split (80:20) into training and holdout subsets. Feature ranking with Least Absolute Shrinkage Selection Operator (LASSO) followed by multivariable stepwise Cox regression in 1000 bootstrapped re-samples of the training data was performed and tested on the holdout data. The fitted regression predictors were used as "scores" for a clinical (C-Score), body composition (B-Score), and radiomics (R-Score) model. To stratify patients into the highest 25% and lowest 25% risk of mortality compared to the middle 50%, the Harrell Concordance Index was used. Results: Based on LASSO and stepwise cox regression for overall survival, ASA ≥3 and age were the most important clinical variables and constituted the C-score, and VAT-index (VATI) was the most important body composition variable and constituted the B-score. Three radiomics features (SATI_original_shape2D_Perimeter, VATI_original_glszm_SmallAreaEmphasis, and VATI_original_firstorder_Maximum) emerged as the most frequent set of features and yielded an R-Score. Of the mean concordance indices of C-, B-, and R-scores, R-score performed best (0.61, 95% CI 0.56-0.65, p<0.001), followed by the C-score (0.59, 95% CI 0.55-0.63, p<0.001) and B-score (0.55, 95% CI 0.50-0.60, p=0.03). Kaplan-Meier projection revealed that C-, B, and R-scores showed a clear split in the survival curves in the training set, although none remained significant in the holdout set. Conclusion: It is feasible to implement a data-driven radiomics approach to body composition imaging. Radiomics features provided improved predictive performance compared to conventional body composition variables for the prediction of overall survival of PDAC patients undergoing primary resection.

A No-Chest-Drain Policy After Video-assisted Thoracoscopic Surgery Wedge Resection in Selected Patients: Our 12-Year Experience.

BACKGROUND: Postoperative pleural drainage omission after video-assisted thoracoscopic surgery (VATS) for wedge resections may facilitate faster recovery. This retrospective cohort study presents our 12-year experience with omitting thoracic drainage in patients who underwent a VATS wedge resection, aiming to assess its safety and efficacy. METHODS: Records from consecutive patients who underwent a VATS wedge resection at our hospital between February 2008 and October 2020 were retrospectively reviewed and assessed for eligibility. Patient and surgical characteristics as well as postoperative data were collected and compared between patients who received a chest drain (CD) or received no chest drain (NCD) after surgery. Univariable and multivariable analyses were performed to determine whether drain placement was associated with complications (primary outcome), and major complications requiring pleural drainage or length of hospital stay (secondary outcomes). RESULTS: Data of 348 patients were analyzed. The drainless group (n = 98) and drain group (n = 237) were significantly different in the following baseline and surgical characteristics: sex, pulmonary function, interstitial lung disease, final pathology, number of wedges, and surgical approach. No significant differences were detected in postoperative complications (NCD 8.2%, CD 14.8%; P = .10), major complications (NCD 5.1%, CD 5.1%; P > .99), or complications requiring pleural drainage (NCD 5.1%, CD 3.8%; P = .56). The drainless group did show a significantly shorter hospitalization (NCD 2 ± 2, CD 3 ± 2 days; P < .001). Multivariable analyses revealed that drain placement was not significantly correlated with postoperative complications. In contrast, prolonged hospitalization was significantly influenced by drain placement. CONCLUSIONS: Our findings suggest that a no-chest-drain policy after VATS wedge resections can safely fast-track rehabilitation for selected patients.

Human pancreatic tumour organoid-derived factors enhance myogenic differentiation.

BACKGROUND: Most patients with pancreatic cancer develop cachexia, which is characterized by progressive muscle loss. The mechanisms underlying muscle loss in cancer cachexia remain elusive. Pancreatic tumour organoids are 3D cell culture models that retain key characteristics of the parent tumour. We aimed to investigate the effect of pancreatic tumour organoid-derived factors on processes that determine skeletal muscle mass, including the regulation of muscle protein turnover and myogenesis. METHODS: Conditioned medium (CM) was collected from human pancreatic cancer cell lines (PK-45H, PANC-1, PK-1, and KLM-1), pancreatic tumour organoid cultures from a severely cachectic (PANCO-9a) and a non-cachectic patient (PANCO-12a), and a normal pancreas organoid culture. Differentiating C2C12 myoblasts and mature C2C12 myotubes were exposed to CM for 24 h or maintained in control medium. In myotubes, NF-kB activation was monitored using a NF-κB luciferase reporter construct, and mRNA expression of E3-ubiquitin ligases and REDD1 was analysed by RT-qPCR. C2C12 myoblast proliferation and differentiation were monitored by live cell imaging and myogenic markers and myosin heavy chain (MyHC) isoforms were assessed by RT-qPCR. RESULTS: Whereas CM from PK-1 and KLM-1 cells significantly induced NF-κB activation in C2C12 myotubes (PK-1: 3.1-fold, P < 0.001; KLM-1: 2.1-fold, P = 0.01), Atrogin-1/MAFbx and MuRF1 mRNA were only minimally and inconsistently upregulated by the CM of pancreatic cancer cell lines. Similarly, E3-ubiquitin ligases and REDD1 mRNA expression in myotubes were not altered by exposure to pancreatic tumour organoid CM. Compared with the control condition, CM from both PANCO-9a and PANCO-12a tumour organoids increased proliferation of myoblasts, which was accompanied by significant downregulation of the satellite cell marker paired-box 7 (PAX7) (PANCO-9a: -2.1-fold, P < 0.001; PANCO-12a: -2.0-fold, P < 0.001) and myogenic factor 5 (MYF5) (PANCO-9a: -2.1-fold, P < 0.001; PANCO-12a: -1.8-fold, P < 0.001) after 48 h of differentiation. Live cell imaging revealed accelerated alignment and fusion of myoblasts exposed to CM from PANCO-9a and PANCO-12a, which was in line with significantly increased Myomaker mRNA expression levels (PANCO-9a: 2.4-fold, P = 0.001; PANCO-12a: 2.2-fold, P = 0.004). These morphological and transcriptional alterations were accompanied by increased expression of muscle differentiation markers such as MyHC-IIB (PANCO-9a: 2.5-fold, P = 0.04; PANCO-12a: 3.1-fold, P = 0.006). Although the impact of organoid CM on myogenesis was not associated with the cachexia phenotype of the donor patients, it was specific for tumour organoids, as CM of control pancreas organoids did not modulate myogenic fusion. CONCLUSIONS: These data show that pancreatic tumour organoid-derived factors alter the kinetics of myogenesis, which may eventually contribute to impaired muscle mass maintenance in cancer cachexia.

Body Composition Is a Predictor for Postoperative Complications After Gastrectomy for Gastric Cancer: a Prospective Side Study of the LOGICA Trial.

PURPOSE: There is a lack of prospective studies evaluating the effects of body composition on postoperative complications after gastrectomy in a Western population with predominantly advanced gastric cancer. METHODS: This is a prospective side study of the LOGICA trial, a multicenter randomized trial on laparoscopic versus open gastrectomy for gastric cancer. Trial patients who received preoperative chemotherapy followed by gastrectomy with an available preoperative restaging abdominal computed tomography (CT) scan were included. The CT scan was used to calculate the mass (M) and radiation attenuation (RA) of skeletal muscle (SM), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT). These variables were expressed as Z-scores, depicting how many standard deviations each patient's CT value differs from the sex-specific study sample mean. Primary outcome was the association of each Z-score with the occurrence of a major postoperative complication (Clavien-Dindo grade ≥ 3b). RESULTS: From 2015 to 2018, a total of 112 patients were included. A major postoperative complication occurred in 9 patients (8%). A high SM-M Z-score was associated with a lower risk of major postoperative complications (RR 0.47, 95% CI 0.28-0.78, p = 0.004). Furthermore, high VAT-RA Z-scores and SAT-RA Z-scores were associated with a higher risk of major postoperative complications (RR 2.82, 95% CI 1.52-5.23, p = 0.001 and RR 1.95, 95% CI 1.14-3.34, p = 0.015, respectively). VAT-M, SAT-M, and SM-RA Z-scores showed no significant associations. CONCLUSION: Preoperative low skeletal muscle mass and high visceral and subcutaneous adipose tissue radiation attenuation (indicating fat depleted of triglycerides) were associated with a higher risk of developing a major postoperative complication in patients treated with preoperative chemotherapy followed by gastrectomy.

Ectopic fat in liver and skeletal muscle is associated with shorter overall survival in patients with colorectal liver metastases.

BACKGROUND: Myosteatosis has been associated with shorter overall survival in cancer patients. The increase in ectopic fat might not be limited to skeletal muscle only and might also extend to other sites such as the liver, resulting in non-alcoholic fatty liver disease (NAFLD). In this study, we assessed the relationship between myosteatosis and NAFLD and their association with overall survival in patients with colorectal liver metastases undergoing partial hepatectomy. METHODS: Patients were selected from a prospective cohort of 289 consecutive patients with colorectal liver metastases. All patients with a preoperative computed tomography (CT)-scan and liver biopsy obtained during surgery were included. If available a second pre-operative CT scan was used to calculate changes in body composition over time. Muscle radiation attenuation was defined as the average Hounsfield units on CT of all muscle tissue at the L3 level. Liver biopsies were graded by a liver pathologist using the steatosis, activity, and fibrosis scoring system for NAFLD. RESULTS: Two-hundred and eighteen patients had an available liver biopsy of which 131 patients had two available pre-operative CT scans with an average time interval of 3.2 months. One-hundred and thirty-five (62%) biopsies were classified as NAFLD. In multivariable Cox-regression analysis, NAFLD [hazard ratio (HR): 1.8, 95%-confidence interval (CI) 1.0-3.0, P = 0.037], increase in myosteatosis (HR 1.8, 95%-CI 1.1-2.9, P = 0.018), and skeletal muscle loss (HR 1.7, 95%-CI 1.0-2.9, P = 0.035) were independently associated with shorter overall survival while high visceral adipose tissue fat content was associated with longer overall survival (HR: 0.7, 95%-CI 0.5-0.9, P = 0.014). CONCLUSIONS: Ectopic fat content of liver as well as skeletal muscle tissue is independently associated with shorter overall survival in patients with colorectal liver metastases, while increased visceral adipose tissue fat content is associated with longer overall survival.

Basal protein synthesis rates differ between vastus lateralis and rectus abdominis muscle.

BACKGROUND: In vivo muscle protein synthesis rates are typically assessed by measuring the incorporation rate of stable isotope labelled amino acids in skeletal muscle tissue collected from vastus lateralis muscle. It remains to be established whether muscle protein synthesis rates in the vastus lateralis are representative of muscle protein synthesis rates of other muscle groups. We hypothesized that post-absorptive muscle protein synthesis rates differ between vastus lateralis and rectus abdominis, pectoralis major, or temporalis muscle in vivo in humans. METHODS: Twenty-four patients (62 ± 3 years, 42% female), scheduled to undergo surgery, participated in this study and underwent primed continuous intravenous infusions with l-[ring-13 C6 ]-phenylalanine. During the surgical procedures, serum samples were collected, and muscle tissue was obtained from the vastus lateralis as well as from the rectus abdominis, pectoralis major, or temporalis muscle. Fractional mixed muscle protein synthesis rates (%/h) were assessed by measuring the incorporation of l-[ring-13 C6 ]-phenylalanine into muscle tissue protein. RESULTS: Serum l-[ring-13 C6 ]-phenylalanine enrichments did not change throughout the infusion period. Post-absorptive muscle protein synthesis rates calculated based upon serum l-[ring-13 C6 ]-phenylalanine enrichments did not differ between vastus lateralis and rectus abdominis (0.032 ± 0.004 vs. 0.038 ± 0.003%/h), vastus lateralis and pectoralis major, (0.025 ± 0.003 vs. 0.022 ± 0.005%/h) or vastus lateralis and temporalis (0.047 ± 0.005 vs. 0.043 ± 0.005%/h) muscle, respectively (P > 0.05). When fractional muscle protein synthesis rates were calculated based upon tissue-free l-[ring-13 C6 ]-phenylalanine enrichments as the preferred precursor pool, muscle protein synthesis rates were significantly higher in rectus abdominis (0.089 ± 0.008%/h) compared with vastus lateralis (0.054 ± 0.005%/h) muscle (P < 0.01). No differences were observed between fractional muscle protein synthesis rates in vastus lateralis and pectoralis major (0.046 ± 0.003 vs. 0.041 ± 0.008%/h) or vastus lateralis and temporalis (0.073 ± 0.008 vs. 0.083 ± 0.011%/h) muscle, respectively. CONCLUSIONS: Post-absorptive muscle protein synthesis rates are higher in rectus abdominis when compared with vastus lateralis muscle. Post-absorptive muscle protein synthesis rates do not differ between vastus lateralis and pectoralis major or temporalis muscle. Protein synthesis rates in muscle tissue samples obtained during surgery do not necessarily represent a good proxy for appendicular skeletal muscle protein synthesis rates.

Edema in critically ill patients leads to overestimation of skeletal muscle mass measurements using computed tomography scans.

OBJECTIVES: Changes in muscle mass and quality are important targets for nutritional intervention in critical illness. Effects of such interventions may be assessed using sequential computed tomography (CT) scans. However, fluid and lipid infiltration potentially affects muscle area measurements. The aim of this study was to evaluate changes in muscle mass and quality in critical illness with special emphasis on the influence of edema on this assessment. METHODS: Changes in skeletal muscle area index (SMI) and radiation attenuation (RA) at the level of vertebra L3 were analyzed using sequential CT scans of 77 patients with abdominal sepsis. Additionally, the relation between these changes and disease severity using the maximum Sequential Organ Failure Assessment (SOFA) score and change in edema were studied. RESULTS: SMI declined on average 0.35%/d (±1.22%; P = 0.013). However, SMI increased in 41.6% of the study population. Increasing edema formation was significantly associated with increased SMI and with a higher SOFA score. Muscle RA decreased during critical illness, but was not significantly associated with changes in SMI or changes in edema. CONCLUSION: In critically ill patients, edema affects skeletal muscle area measurements, which leads to an overestimation of skeletal muscle area. A higher SOFA score was associated with edema formation. Because both edema and fat infiltration may affect muscle RA, the separate effects of these on muscle quality are difficult to distinguish. When using abdominal CT scans to changes in muscle mass and quality in critically ill patients, researchers must be aware and careful with the interpretation of the results.

Gut microbiota and short-chain fatty acid alterations in cachectic cancer patients.

BACKGROUND: Cancer cachexia is characterized by a negative energy balance, muscle and adipose tissue wasting, insulin resistance, and systemic inflammation. Because of its strong negative impact on prognosis and its multifactorial nature that is still not fully understood, cachexia remains an important challenge in the field of cancer treatment. Recent animal studies indicate that the gut microbiota is involved in the pathogenesis and manifestation of cancer cachexia, but human data are lacking. The present study investigates gut microbiota composition, short-chain fatty acids (SCFA), and inflammatory parameters in human cancer cachexia. METHODS: Faecal samples were prospectively collected in patients (N = 107) with pancreatic cancer, lung cancer, breast cancer, or ovarian cancer. Household partners (N = 76) of the patients were included as healthy controls with similar diet and environmental conditions. Patients were classified as cachectic if they lost >5% body weight in the last 6 months. Gut microbiota composition was analysed by sequencing of the 16S rRNA V4 gene region. Faecal SCFA levels were quantified by gas chromatography. Faecal calprotectin was assessed with enzyme-linked immunosorbent assay. Serum C-reactive protein and leucocyte counts were retrieved from medical records. RESULTS: Cachexia prevalence was highest in pancreatic cancer (66.7%), followed by ovarian cancer (25%), lung cancer (20.8%), and breast cancer (17.3%). Microbial α-diversity was not significantly different between cachectic cancer patients (N = 33), non-cachectic cancer patients (N = 74), or healthy controls (N = 76) (species richness P = 0.31; Shannon effective index P = 0.46). Community structure (ß-diversity) tended to differ between these groups (P = 0.053), although overall differences were subtle and no clear clustering of samples was observed. Proteobacteria (P < 0.001), an unknown genus from the Enterobacteriaceae family (P < 0.01), and Veillonella (P < 0.001) were more abundant among cachectic cancer patients. Megamonas (P < 0.05) and Peptococcus (P < 0.001) also showed differential abundance. Faecal levels of all SCFA tended to be lower in cachectic cancer patients, but only acetate concentrations were significantly reduced (P < 0.05). Faecal calprotectin levels were positively correlated with the abundance of Peptococcus, unknown Enterobacteriaceae, and Veillonella. We also identified several correlations and interactions between clinical and microbial parameters. CONCLUSIONS: This clinical study provided the first insights into the alterations of gut microbiota composition and SCFA levels that occur in cachectic cancer patients and how they are related to inflammatory parameters. These results pave the way for further research examining the role of the gut microbiota in cancer cachexia and its potential use as therapeutic target.

Generation and initial characterization of novel tumour organoid models to study human pancreatic cancer-induced cachexia.

BACKGROUND: The majority of patients with pancreatic cancer develops cachexia. The mechanisms underlying cancer cachexia development and progression remain elusive, although tumour-derived factors are considered to play a major role. Pancreatic tumour organoids are in vitro three-dimensional organ-like structures that retain many pathophysiological characteristics of the in vivo tumour. We aimed to establish a pancreatic tumour organoid biobank from well-phenotyped cachectic and non-cachectic patients to enable identification of tumour-derived factors driving cancer cachexia. METHODS: Organoids were generated from tumour tissue of eight pancreatic cancer patients. A comprehensive pre-operative patient assessment of cachexia-related parameters including nutritional status, physical performance, body composition, and inflammation was performed. Tumour-related and cachexia-related characteristics of the organoids were analysed using histological stainings, targeted sequencing, and real-time-quantitative PCR. Cachexia-related factors present in the circulation of the patients and in the tumour organoid secretome were analysed by enzyme-linked immunosorbent assay. RESULTS: The established human pancreatic tumour organoids presented typical features of malignancy corresponding to the primary tumour (i.e. nuclear enlargement, multiple nucleoli, mitosis, apoptosis, and mutated KRAS and/or TP53). These tumour organoids also expressed variable levels of many known cachexia-related genes including interleukin-6 (IL-6), TNF-α, IL-8, IL-1α, IL-1ß, Mcp-1, GDF15, and LIF. mRNA expression of IL-1α and IL-1ß was significantly reduced in organoids from cachectic vs. non-cachectic patients (IL-1α: -3.8-fold, P = 0.009, and IL-1ß: -4.7-fold, P = 0.004). LIF, IL-8, and GDF15 mRNA expression levels were significantly higher in organoids from cachectic vs. non-cachectic patients (LIF: 1.6-fold, P = 0.003; IL-8: 1.4-fold, P = 0.01; GDF15: 2.3-fold, P < 0.001). In line with the GDF15 and IL-8 mRNA expression levels, tumour organoids from cachectic patients secreted more GDF15 and IL-8 compared with organoids from non-cachectic patients (5.4 vs. 1.5 ng/mL, P = 0.01, and 7.4 vs. 1.3 ng/mL, P = 0.07, respectively). CONCLUSIONS: This novel human pancreatic tumour organoid biobank provides a valuable tool to increase our understanding of the mechanisms driving cancer cachexia. Our preliminary characterization of the secretome of these organoids supports their application in functional studies including conditioned medium approaches and in vivo transplantation models.

Muscle wasting associated co-morbidities, rather than sarcopenia are risk factors for hospital mortality in critical illness.

BACKGROUND: Low skeletal muscle mass on intensive care unit admission is related to increased mortality. It is however unknown whether this association is influenced by co-morbidities that are associated with skeletal muscle loss. The aim of this study was to investigate whether sarcopenia is an independent risk factor for hospital mortality in critical illness in the presence of co-morbidities associated with muscle wasting. METHODS: Data of 155 patients with abdominal sepsis were retrospectively analyzed. Skeletal muscle area was assessed using CT-scans at the level of vertebra L3. Demographic and clinical data were retrieved from electronic patient files. Sarcopenia was defined as a muscle area index below the 5th percentile of the general population. Uni- and multivariable analyses were performed to assess the association between sarcopenia and hospital mortality, correcting for age and comorbidities. RESULTS: The prevalence of sarcopenia was higher in patients that did not survive until hospital discharge. However, it appeared that this relation was confounded by the presence of chronic renal insufficiency and cancer. These were independent risk factors for hospital mortality, whereas sarcopenia was not. CONCLUSION: In critically ill patients with abdominal sepsis, muscle wasting associated co-morbidities rather than sarcopenia were risk factors for hospital mortality.

Evaluation of the Palutop+4 malaria rapid diagnostic test in a non-endemic setting.

BACKGROUND: Palutop+4 (All. Diag, Strasbourg, France), a four-band malaria rapid diagnostic test (malaria RDT) targeting the histidine-rich protein 2 (HRP-2), Plasmodium vivax-specific parasite lactate dehydrogenase (Pv-pLDH) and pan Plasmodium-specific pLDH (pan-pLDH) was evaluated in a non-endemic setting on stored whole blood samples from international travellers suspected of malaria. METHODS: Microscopy corrected by PCR was the reference method. Samples include those infected by Plasmodium falciparum (n = 323), Plasmodium vivax (n = 97), Plasmodium ovale (n = 73) and Plasmodium malariae (n = 25) and 95 malaria negative samples. RESULTS: The sensitivities for the diagnosis of P. falciparum, P. vivax, P. malariae and P. ovale were 85.1%, 66.0%, 32.0% and 5.5%. Sensitivities increased at higher parasite densities and reached 90.0% for P. falciparum >100/microl and 83.8% for P. vivax > 500/microl. Fourteen P. falciparum samples reacted with the Pv-pLDH line, one P. vivax sample with the HRP-2 line, and respectively two and four P. ovale and P. malariae samples reacted with the HRP-2 line. Two negative samples gave a signal with the HRP-2 line. Faint and weak line intensities were observed for 129/289 (44.6%) HRP-2 lines in P. falciparum samples, for 50/64 (78.1%) Pv-pLDH lines in P. vivax samples and for 9/13 (69.2%) pan-pLDH lines in P. ovale and P. malariae samples combined. Inter-observer reliabilities for positive and negative readings were excellent for the HRP-2 and Pv-pLDH lines (overall agreement > 92.0% and kappa-values for each pair of readers >or= 0.88), and good for the pan-pLDH line (85.5% overall agreement and kappa-values >or= 0.74). CONCLUSIONS: Palutop+4 performed moderately for the detection of P. falciparum and P. vivax, but sensitivities were lower than those of three-band malaria RDTs.

Test characteristics of the SD FK80 Plasmodium falciparum/Plasmodium vivax malaria rapid diagnostic test in a non-endemic setting.

BACKGROUND: The SD FK80 P.f/P.v Malaria Antigen Rapid Test (Standard Diagnostics, Korea) (FK80) is a three-band malaria rapid diagnostic test detecting Plasmodium falciparum histidine-rich protein-2 (HRP-2) and Plasmodium vivax-specific lactate dehydrogenase (Pv-pLDH). The present study assessed its performance in a non-endemic setting. METHODS: Stored blood samples (n = 416) from international travellers suspected of malaria were used, with microscopy corrected by PCR as the reference method. Samples infected by Plasmodium falciparum (n = 178), Plasmodium vivax (n = 99), Plasmodium ovale (n = 75) and Plasmodium malariae (n = 24) were included, as well as 40 malaria negative samples. RESULTS: Overall sensitivities for the diagnosis of P. falciparum and P. vivax were 91.6% (95% confidence interval (CI): 86.2% - 95.0%) and 75.8% (65.9% - 83.6%). For P. falciparum, sensitivity at parasite densities >or= 100/microl was 94.6% (88.8% - 97.6%); for P. vivax, sensitivity at parasite densities >or= 500/microl was 86.8% (75.4% - 93.4%). Four P. falciparum samples showed a Pv-pLDH line, three of them had parasite densities exceeding 50.000/microl. Two P. vivax samples, one P. ovale and one P. malariae sample showed a HRP-2 line. For the HRP-2 and Pv-pLDH lines, respectively 81.4% (136/167) and 55.8% (43/77) of the true positive results were read as medium or strong line intensities. The FK80 showed good reproducibility and reliability for test results and line intensities (kappa values for both exceeding 0.80). CONCLUSION: The FK80 test performed satisfactorily in diagnosing P. falciparum and P. vivax infections in a non-endemic setting.