Scope
In recent years, there has been a growing body of evidence pointing to an effect of vitamin D on muscle mass and function. Our aim was to investigate the combined effect of 1,25(OH)2‐vitamin D3 ...(1,25(OH)2D3) with anabolic factors insulin and leucine on protein fractional synthesis rate (FSR) and regulation in the mouse C2C12 myotube.
Methods and results
After differentiation, myotubes were cultured in 1,25(OH)2D3 solutions at 0, 1, or 10 nM for 72 h. Cells were treated by l‐1–13Cvaline and puromycin in presence or not of leucine and insulin, and protein FSR was determined by measuring tracer enrichments and puromycin incorporation in proteins, respectively. Protein expression and phosphorylation state of insulin receptor (IR), Akt, GSK3, mTOR, p70 S6 kinase, rpS6, and 4EBP1 were measured by Western blot. Transcript levels of IR and 1,25(OH)2D3 receptor (VDR) were determined by qPCR. 1,25(OH)2D3 (10 nM) with leucine and insulin increased protein FSR in C2C12 myotubes (14–16%). IR and VDR mRNA expression was increased with 1,25(OH)2D3 treatment. The Akt/mTOR‐dependent pathway was activated by insulin and leucine and further enhanced by 1,25(OH)2D3.
Conclusion
1,25(OH)2D3 sensitizes the Akt/mTOR‐dependant pathway to the stimulating effect of leucine and insulin, resulting in a further activation of protein synthesis in murine C2C12 skeletal myotubes.
Background
Increasing evidence suggests that severe skeletal muscle index (SMI) loss (sarcopenia) is associated with poor overall survival in metastatic colorectal cancer patients, but its mechanisms ...are unknown. We recently found, using data of the randomized phase 3 CAIRO3 study, that SMI loss was related with shorter time to disease progression and overall survival during first‐line maintenance treatment with capecitabine + bevacizumab (CAP‐B) or observation and during more intensive capecitabine + oxaliplatin + bevacizumab (CAPOX‐B) reintroduction treatment. As a potential risk factor for reduced survival, we explored whether sarcopenia and SMI loss were associated with dose‐limiting toxicities (DLTs) during CAP‐B and CAPOX‐B.
Methods
Sarcopenia status and SMI loss were assessed by using consecutive computed tomography scans. DLTs were defined as any dose delay/reduction/discontinuation of systemic treatment because of reported CTCAE (version 3.0) toxicities at the start or during treatment. Poisson regression models were used to study whether sarcopenia and body mass index (BMI) at the start of treatment and SMI and BMI loss during treatment were associated with DLTs.
Results
One hundred eighty‐two patients (mean age 63.0 ± 8.8 years, 37% female) received CAP‐B, and 232 patients (mean age 63.0 ± 9.0 years, 34% female) received CAPOX‐B. At the start of CAP‐B and CAPOX‐B, 54% and 46% of patients were sarcopenic, respectively. Mean BMI was lower in sarcopenic patients, although patients were on average still overweight (sarcopenic vs. non‐sarcopenic at the start of CAP‐B 25.0 ± 3.9 vs. 26.7 ± 4.1 and CAPOX‐B 25.8 ± 3.8 vs. 27.1 ± 3.8 kg/m2). Sarcopenia at the start of CAP‐B was not associated with DLTs relative risk 0.87 (95% confidence interval 0.64–1.19), whereas patients with >2% SMI loss had a significantly higher risk of DLTs 1.29 (1.01–1.66). At the start of subsequent CAPOX‐B, 25% of patients received a dose reduction, and the risk of dose reduction was significantly higher for patients with preceding SMI loss 1.78 (1.06–3.01) or sarcopenia 1.75 (1.08–2.86). After the received dose reductions, sarcopenia or SMI loss was not significantly associated with a higher risk of DLTs during CAPOX‐B sarcopenia vs. non‐sarcopenic: 0.86 (0.69–1.08) and SMI loss vs. stable/gain: 0.83 (0.65–1.07). In contrast, BMI (loss) at the start or during either treatment was not associated with an increased risk of DLTs.
Conclusions
In this large longitudinal study in metastatic colorectal cancer patients during palliative systemic treatment, sarcopenia and/or muscle loss was associated with an increased risk of DLTs. BMI was not associated with DLTs and could not detect sarcopenia or SMI loss. Prospective (randomized) studies should reveal whether normalizing chemotherapeutic doses to muscle mass or muscle mass preservation (by exercise and nutritional interventions) increases chemotherapeutic tolerance and improves survival.
Summary Background & aims Amino acid (AA) availability is critical to maintain protein homeostasis and reduced protein intake causes a decline in protein synthesis. Citrulline, an amino acid ...metabolite, has been reported to stimulate muscle protein synthesis in malnourished rats. Methods To determine whether citrulline stimulates muscle protein synthesis in healthy adults while on a low-protein diet, we studied 8 healthy participants twice in a cross-over study design. Following a 3-days of low-protein intake, either citrulline or a non-essential AA mixture (NEAA) was given orally as small boluses over the course of 8 h. ring-13 C6 phenylalanine and 15 N tyrosine were administered as tracers to assess protein metabolism. Fractional synthesis rates (FSR) of muscle proteins were measured using phenylalanine enrichment in muscle tissue fluid as the precursor pool. Results FSR of mixed muscle protein was higher during the administration of citrulline than during NEAA (NEAA: 0.049 ± 0.005; citrulline: 0.060 ± 0.006; P = 0.03), while muscle mitochondrial protein FSR and whole-body protein turnover were not different between the studies. Citrulline administration increased arginine and ornithine plasma concentrations without any effect on glucose, insulin, C-peptide, and IGF-1 levels. Citrulline administration did not promote mitochondria protein synthesis, transcripts, or citrate synthesis. Conclusions Citrulline ingestion enhances mixed muscle protein synthesis in healthy participants on 3-day low-protein intake. This anabolic action of citrulline appears to be independent of insulin action and may offer potential clinical application in conditions involving low amino acid intake.
Equine herpesvirus 1 (EHV-1) is an Alphaherpesvirus infecting not only horses but also other equid and non-equid mammals. It can cause respiratory distress, stillbirth and neonatal death, abortion, ...and neurological disease. The different forms of disease induced by EHV-1 infection can have dramatic consequences on the equine industry, and thus the virus represents a great challenge for the equine and scientific community. This report describes the progress of a major EHV-1 outbreak that took place in Normandy in 2009, during which the three forms of disease were observed. A collection of EHV-1 strains isolated in France and Belgium from 2012 to 2018 were subsequently genetically analysed in order to characterise EHV-1 strain circulation. The open reading frame 30 (ORF30) non-neuropathogenic associated mutation A2254 was the most represented among 148 samples analysed in this study. ORF30 was also sequenced for 14 strains and compared to previously published sequences. Finally, a more global phylogenetic approach was performed based on a recently described Multilocus Sequence Typing (MLST) method. French and Belgian strains were clustered with known strains isolated in United Kingdom and Ireland, with no correlation between the phylogeny and the time of collection or location. This new MLST approach could be a tool to help understand epidemics in stud farms.
Background
Observational studies suggest that loss of skeletal muscle mass (SMM) is associated with chemotherapy‐related toxicity, poor quality of life, and poor survival in metastatic colorectal ...cancer (mCRC) patients. Little is known about the evolution of SMM during palliative systemic therapy. We investigated changes in SMM during various consecutive palliative systemic treatment regimens using repeated abdominal computed tomography scans of mCRC patients who participated in the randomized phase 3 CAIRO3 study.
Methods
In the CAIRO3 study, mCRC patients with stable disease or better after 6 cycles of first‐line treatment with capecitabine + oxaliplatin + bevacizumab (CAPOX‐B) were randomized between maintenance treatment with capecitabine + bevacizumab (CAP‐B) or observation. Upon first disease progression, in both groups, CAPOX‐B or other treatment was reintroduced until the second disease progression, which was the primary study endpoint. We analysed 1355 computed tomography scans of 450 (81%) CAIRO3 patients (64 ± 9.0 years, CAP‐B n = 223; observation n = 227) for SMM at four time points (i.e. prior to the start of pre‐randomization initial treatment, at randomization, and at first and at second disease progression) using the Slice‐o‐matic software and single slice evaluation at the lumbar 3 level. By using accepted and widely used formulas, whole body SMM was calculated. A linear mixed effects model, adjusted for relevant confounders, was used to assess SMM changes for the total group and within and between study arms.
Results
During 6 cycles of initial treatment with CAPOX‐B prior to randomization, SMM decreased significantly in all patients CAP‐B arm: −0.53 kg (95% CI −1.12; −0.07) and observation arm: −0.85 kg (−1.45; −0.25). After randomization, SMM recovered during CAP‐B treatment by 1.32 kg (0.73; 1.90) and observation by 1.20 kg (0.63; 1.78) (median time from randomization to first disease progression 8.6 and 4.1 months for CAP‐B arm and observation arm, respectively). After first progression and during reintroduction treatment with CAPOX‐B or other treatment, SMM again decreased significantly and comparable in both arms, CAP‐B: −2.71 kg (−3.37; −2.03), and observation: −2.01 kg (−2.64; −1.41) (median time from first progression until second progression CAP‐B arm: 4.7 months and observation arm: 6.6 months).
Conclusions
This longitudinal study provides a unique insight in SMM changes in mCRC patients during palliative systemic treatment regimens, including observation. Our data show that muscle loss is reversible and may be influenced by the intensity of systemic regimens. Although studies have shown prognostic capacity for SMM, the effects of subsequent changes in SMM are unknown and may be clues for new future therapeutic interventions.
Skeletal muscle mitochondrial function is the biggest component of whole-body energy output. Mitochondrial energy production during exercise is impaired in vitamin D-deficient subjects. In cultured ...myotubes, loss of vitamin D receptor (VDR) function decreases mitochondrial respiration rate and ATP production from oxidative phosphorylation. We aimed to examine the effects of vitamin D deficiency and supplementation on whole-body energy expenditure and muscle mitochondrial function in old rats, old mice, and human subjects. To gain further insight into the mechanisms involved, we used C2C12 and human muscle cells and transgenic mice with muscle-specific VDR tamoxifen-inducible deficiency. We observed that in vivo and in vitro vitamin D fluctuations changed mitochondrial biogenesis and oxidative activity in skeletal muscle. Vitamin D supplementation initiated in older people improved muscle mass and strength. We hypothesize that vitamin D supplementation is likely to help prevent not only sarcopenia but also sarcopenic obesity in vitamin D-deficient subjects.
Every year, several epizooties of equine influenza (EI) are reported worldwide. However, no EI case has been identified in France between 2015 and late 2018, despite an effective field surveillance ...of the pathogen and the disease. Vaccination against equine influenza virus (EIV) remains to this day one of the most effective methods to prevent or limit EI outbreaks and the lack of detection of the pathogen could be linked to vaccination coverage. The aim of this study was to evaluate EI immunity and vaccine coverage in France through a large-scale serological study. A total of 3004 archived surplus serums from French horses of all ages, breeds and sexes were selected from four different geographical regions and categories (i.e., sanitary check prior to exportation, sale, breeding protocol or illness diagnosis). EIV-specific antibody response was measured by single radial hemolysis (SRH) and an EIV-nucleoprotein (NP) ELISA (used as a DIVA test). Overall immunity coverage against EIV infection (i.e., titers induced by vaccination and/or natural infection above the clinical protection threshold) reached 87.6%. The EIV NP ELISA results showed that 83% of SRH positive serum samples from young horses (≤3 years old) did not have NP antibodies, which indicates that the SRH antibody response was likely induced by EI vaccination alone (the HA recombinant canarypoxvirus-based EI vaccine is mostly used in France) and supports the absence of EIV circulation in French horse populations between 2015 and late 2018, as reported by the French equine infectious diseases surveillance network (RESPE). Results from this study confirm a strong EI immunity in a large cohort of French horses, which provides an explanation to the lack of clinical EI in France in recent years and highlights the success of vaccination against this disease. However, such EI protection has been challenged since late 2018 by the incursion in the EU of a Florida Clade 1 sub-lineage EIV (undetected in France since 2009), which is also reported here.
Background
Skeletal muscle mass (SMM) loss is common in metastatic colorectal cancer (mCRC) patients and associated with poor clinical outcomes, including increased treatment‐related toxicities and ...reduced survival. Muscle loss may contribute to reduced health‐related quality of life (HRQoL), including fatigue. Our aim was to study associations between changes in SMM and concomitant changes in patient‐reported HRQoL.
Methods
This was a secondary analysis of mCRC patients in the CAIRO3 randomized clinical trial who were—after initial treatment—randomized between maintenance treatment with capecitabine plus bevacizumab (CAP‐B) and observation until first disease progression (PD1). Included patients had computed tomography images for SMM quantification, together with HRQoL assessments available at randomization and PD1. Changes in SMM (categorized as >2% loss, stable, and >2% gain) and HRQoL were computed between randomization and PD1. Changes in HRQoL score >10 points were considered clinically relevant. Associations between SMM and HRQoL changes were studied by multiple linear regression models. We also investigated whether associations differed by treatment arm for global health and the 13 other HRQoL subscales.
Results
Of 221 patients included (mean age 63.5 ± 8.4 years), 24% lost, 27% remained stable, and 49% gained SMM. At randomization, mean global health status was 73.5 ± 15.9 in the CAP‐B arm and 75.1 ± 17.5 in the observation arm (P = 0.48). A stable or gain in SMM was significantly associated with a clinically relevant improvement in global health status (9.9 and 14.7 points, respectively), compared with patients who lost SMM. From the subscales that did not show significant differences between the two treatment arms, we found significant and clinically relevant associations for stable or gain in SMM with improved role functioning (12.0 and 17.9, respectively) and with less fatigue (−10.0 and −15.0, respectively) and pain (−16.3 for SMM gain). From the subscales that did show significantly different associations with SMM between the two treatment arms, we only found significant results in the observation arm. Here, associations were found for stable or gain in SMM with clinically relevant improved physical (12.4 for SMM gain), cognitive (10.7 and 9.7, respectively), and social functioning (15.5 and 15.6, respectively) as well as reduced appetite loss (−28.5 and −30.7, respectively).
Conclusions
In mCRC, SMM preservation during CAP‐B and observation treatment is associated with significant and clinically relevant improvements in global health status and multiple functional and symptom scales. Studies are warranted to investigate whether interventions targeting SMM lead to improved HRQoL, fewer symptoms, and better functioning.
Rift Valley fever is an acute, zoonotic viral disease of domestic ruminants, caused by a phlebovirus (Bunyaviridae family). A large outbreak occurred in Madagascar in 2008-2009. The goal of the ...present study was to evaluate the point prevalence of antibodies against Rift Valley Fever Virus (RVFV) in cattle in the Anjozorobe district, located in the wet and temperate highland region of Madagascar and yet heavily affected by the disease, and analyse environmental and trade factors potentially linked to RVFV transmission. A serological study was performed in 2009 in 894 bovines. For each bovine, the following variables were recorded: age, location of the night pen, minimum distance from the pen to the nearest water point and the forest, nearest water point type, and herd replacement practices. The serological data were analyzed using a generalized linear mixed model. The overall anti-RVFV IgG seroprevalence rate was 28% CI95% 25-31. Age was statistically linked to prevalence (p = 10(-4)), being consistent with a recurrent RVFV circulation. Distance from the night pen to the nearest water point was a protective factor (p = 5.10(-3)), which would be compatible with a substantial part of the virus transmission being carried out by nocturnal mosquito vectors. However, water point type did not influence the risk of infection: several mosquito species are probably involved. Cattle belonging to owners who purchase animals to renew the herd were significantly more likely to have seroconverted than others (p = 0.04): cattle trade may contribute to the introduction of the virus in this area. The minimum distance of the night pen to the forest was not linked to the prevalence. This is the first evidence of a recurrent transmission of RVFV in such an ecosystem that associates a wet, temperate climate, high altitude, paddy fields, and vicinity to a dense rain forest. Persistence mechanisms need to be further investigated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Low skeletal muscle index (SMI) in metastatic colorectal cancer (mCRC) patients is associated with poor outcomes. The prognostic impact of SMI changes during consecutive palliative ...systemic treatments is unknown.
Methods
This is a retrospective analysis of the phase 3 CAIRO3 study. The CAIRO3 study randomized 557 patients between maintenance capecitabine + bevacizumab (CAP‐B) or observation, after six cycles capecitabine + oxaliplatin + bevacizumab (CAPOX‐B). Upon first disease progression (PD1), CAPOX‐B was reintroduced until second progression (PD2). SMI was assessed by computed tomography (CT) (total 1355 scans). SMI and body mass index (BMI) changes were analyzed for three time‐periods; p1: during initial CAPOX‐B, p2: randomization to PD1, and p3: PD1 to PD2. The association between absolute and change in SMI and BMI (both per 1 standard deviation) during p1‐p3, with PD1, PD2, and survival was studied by Cox regression models.
Results
This analysis included 450 of the 557 patients randomized in the CAIRO3 study. Mean SMI decreased during p1: mean −0.6 SMI units 95% CI −1.07;‐0.26 and p3: −2.2 units −2.7;‐1.8, whereas during p2, SMI increased + 1.2 units 0.8‐1.6. BMI changes did not reflect changes in SMI. SMI loss during p2 and p3 was significantly associated with shorter survival (HR 1.19 1.09‐1.35; 1.54 1.31‐1.79, respectively). Sarcopenia at PD1 was significantly associated with early PD2 (HR 1.40 1.10‐1.70). BMI loss independent of SMI loss was only associated with shorter overall survival during p3 (HR 1.35 1.14‐1.63).
Conclusions
In mCRC patients, SMI loss during palliative systemic treatment was related with early disease progression and reduced survival. BMI did not reflect changes in SMI and could not identify patients at risk of poor outcome during early treatment lines.
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