MRI of a presumptive intracranial histiocytic sarcoma with extracranial extension in a cat.

Case summary: A 4-year-old female neutered Scottish Fold shorthair cat was presented for further investigation of circling towards the right. MRI of the brain revealed an extensive, right-sided temporal muscle lesion with associated frontotemporal bone osteolysis, intracranial, extra-axial extension along the calvarial convexity with severe pachy- and leptomeningeal thickening and contrast enhancement, and an intra-axial space-occupying lesion in the right piriform lobe. The regional lymph nodes were moderately enlarged. Cytology of the right parotid lymph node and the temporal muscle was performed and histiocytic sarcoma (HS) was diagnosed. The owners elected euthanasia. Relevance and novel information: HS of the central nervous system (CNS) is a very rare neoplastic condition in cats. Although a few case reports mention MRI, to our knowledge, the characterisation of MRI features of feline CNS HS have not been investigated in detail. Therefore, the aim of this case report was to describe the MRI characteristics in a feline HS involving not only the CNS, but also the fronto-temporal bone, temporal muscle and the regional lymph nodes. In particular, aggressive neoplastic bone invasion was a novel finding.

Research Note: Carcass yield and meat quality in high- and low-water efficient broiler lines exposed to heat stress.

Heat stress (HS) and water scarcity are significant challenges to sustainable poultry production worldwide. It is, therefore, critical to identify effective strategies to prevent, withstand, or adapt to these challenges. After four generations of divergent selection for water efficiency, the present study was undertaken to determine the effect of HS on meat quality and muscle myopathy incidences in high (HWE)- and low (LWE)-water efficient broilers. Day-old male chicks (240 chicks/line) were allotted randomly by line and body weight-matched groups to 12 controlled-environmental chambers (2 pens/chamber). At d29, birds were exposed to 2 environmental conditions (thermoneutral (TN), 25°C; or cyclic HS, 36°C, 9h/d) in a 2 × 2 factorial design. On d49, birds were processed, carcass parts were weighed, meat quality and muscle myopathy incidence were assessed. Processing data were analyzed by Two-way ANOVA and Tukey's HSD multiple comparison test, and frequency of muscle myopathy score between groups was determined using Chi-square and Fisher's exact test. Significance was set at P < 0.05. As no significant environment by line interaction was discerned, the 2 main factors were analyzed separately. High water efficient birds had significantly higher tender- and leg quarter (LQ)-weight as well as carcass without giblet (WOG), chilled carcass WOG (CWOG), wing, LQ, and rack yields compared to their LWE counterparts. Both abdominal fat content and yields were significantly greater in LWE than HWE chickens. Chronic HS exposure significantly decreased dock, WOG, fat, CWOG, breast, tender, wing, and LQ weights as well as breast yield. HWE chickens had a significantly lower b* value compared to the LWE birds and HS significantly reduced the drip loss and the b* value compared to TN condition. Compared to LWE, HWE birds had higher and lower incidence of severe woody breast (WB) and white striping (WS) under TN and HS, respectively. HS reduced the incidence of both myopathies in both lines. In conclusion, the genetic selection for water efficiency seems to improve carcass yield, reduce fat content, and decrease the breast b* value. HWE birds had higher incidences of WB and WS under TN, which is reversed under HS conditions.

Impact of Phytase Supplementation on Meat Quality of Heat-Stressed Broilers.

Heat stress (HS) is one of the most challenging stressors to poultry production sustainability. The adverse effects of HS range from feed intake and growth depression to alteration of meat quality and safety. As phytase supplementation is known to improve nutrient utilization and consequently growth, we undertook the present study to evaluate the effects of dietary phytase on growth and meat quality in heat-stressed broilers. A total of 720 day-old hatch Cobb 500 chicks were assigned to 24 pens within controlled environmental chambers and fed three diets: Negative Control (NC), Positive Control (PC), and NC diet supplemented with 2000 phytase units (FTU)/kg) of quantum blue (QB). On day 29, birds were exposed to two environmental conditions: thermoneutral (TN, 25 °C) or cyclic heat stress (HS, 35 °C, 8 h/d from 9 a.m. to 5 p.m.) in a 3 × 2 factorial design. Feed intake (FI), water consumption (WI), body weight (BW), and mortality were recorded. On day 42, birds were processed, carcass parts were weighed, and meat quality was assessed. Breast tissues were collected for determining the expression of target genes by real-time quantitative PCR using the 2-ΔΔCt method. HS significantly increased core body temperature, reduced feed intake and BW, increased water intake (WI), elevated blood parameters (pH, SO2, and iCa), and decreased blood pCO2. HS reduced the incidence of woody breast (WB) and white striping (WS), significantly decreased drip loss, and increased both 4- and 24-h postmortem pH. Instrumental L* and b* values were reduced (p < 0.05) by the environmental temperature at both 4- and 24-h postmortem. QB supplementation reduced birds' core body temperature induced by HS and improved the FCR and water conversion ratio (WCR) by 1- and 0.5-point, respectively, compared to PC under HS. QB increased blood SO2 and reduced the severity of WB and WS under TN conditions, but it increased it under an HS environment. The abovementioned effects were probably mediated through the modulation of monocarboxylate transporter 1, heat shock protein 70, mitogen-activated protein kinase, and/or glutathione peroxidase 1 gene expression, however, further mechanistic studies are warranted. In summary, QB supplementation improved growth performance and reduced muscle myopathy incidence under TN conditions. Under HS conditions, however, QB improved growth performance but increased the incidence of muscle myopathies. Therefore, further QB titration studies are needed.

PTEN-AKT pathway attenuates apoptosis and adverse remodeling in ponatinib-induced skeletal muscle toxicity following BMP-7 treatment.

Tyrosine kinase inhibitors (TKIs) including ponatinib are commonly used to treat cancer patients. Unfortunately, TKIs induce cardiac as well as skeletal muscle dysfunction as a side effect. Therefore, detailed mechanistic studies are required to understand its pathogenesis and to develop a therapeutic treatment. The current study was undertaken to examine whether ponatinib induces apoptosis and apoptotic mechanisms both in vitro and in vivo models and furthermore to test the potential of bone morphogenetic protein 7 (BMP-7) as a possible treatment option for its attenuation. Sol8 cells, a mouse myogenic cell line was exposed to ponatinib to generate an apoptotic cell culture model and were subsequently treated with BMP-7 to understand its protective effects. For the in vivo model, C57BL/6J mice were administered with ponatinib to understand apoptosis, cell signaling apoptotic mechanisms, and adverse muscle remodeling and its attenuation with BMP-7. TUNEL staining, immunohistochemistry (IHC), and real-time polymerase chain reaction (RT-PCR) methods were used. Our data show significantly (p < 0.05) increased TUNEL staining, caspase-3, BAX/Bcl2 ratio in the in vitro model. Furthermore, our in vivo muscle data show ponatinib-induced muscle myopathy, and loss in muscle function. The observed muscle myopathy was associated with increased apoptosis, caspase-3 staining, and BAX/Bcl-2 ratio as confirmed with IHC and RT-PCR. Furthermore, our data show a significant (p < 0.05) increase in the involvement of cell signaling apoptotic regulator protein PTEN and a decrease in cell survival protein AKT. These results suggest that increased apoptosis following ponatinib treatment showed an increase in skeletal muscle remodeling, sarcopenia, and fibrosis. Furthermore, BMP-7 treatment significantly (p < 0.05) attenuated ponatinib-induced apoptosis, BAX/Bcl2 ratio, decreased PTEN, and increased cell survival protein AKT, decreased adverse muscle remodeling, and improved muscle function. Overall, we provide evidence that ponatinib-induces apoptosis leading to sarcopenia and muscle myopathy with decreased function which was attenuated by BMP-7.

Cecal microbiota contribute to the development of woody breast myopathy.

The objective of this study was to characterize the bacterial diversity of cecal microbiota in broilers related to breast phenotype, diet, and genetic strain. Broilers from 2 genetic strains (120 birds/strain) were fed a control diet (15 birds/pen) and an amino acid reduced diet (15 birds/pen, digestible lysine, total sulfur amino acids, and threonine reduced by 20% compared to the control diet). At 8 wk of age, 4 male broilers with normal breast (NB, 1 chick per pen) and 4 male broilers with woody breast (WB, 1 chick per pen) were selected for each treatment (strain × diet). The DNA of cecal samples was extracted and the 16S rRNA genes were sequenced and analyzed. There were no differences (P > 0.05) in the alpha diversity of gut microbiota between 2 phenotypes (NB vs. WB), 2 strains, or 2 diets (control vs. reduced). However, principal coordinate analysis plots (beta diversity) revealed that there were composition differences in samples between the 2 phenotypes (P = 0.001) and the 2 diets (P = 0.024). The most abundant phyla in all samples were Firmicutes, followed by Bacteroidetes and Proteobacteria. There were differences (false discovery rate, FDR < 0.05) in bacterial relative abundance between phenotypes and between diet treatments, but not (FDR > 0.05) between the 2 genetic strains. Selenomonas bovis (12.6%) and Bacteroides plebeius (12.3%) were the top 2 predominant bacteria in the ceca of WB birds; however, the relative abundances of these 2 bacteria were only 5.1% and 1.2% in NB birds, respectively. Function analysis predicted that the metabolic activities differed (q < 0.05) only between phenotypes. The microbiota of WB birds was characterized as reduced glycolysis and urea cycle but increased tricarboxylic acid (TCA) cycles, sugar degradation, and purine and pyrimidine nucleotides biosynthesis. Further studies are needed to investigate if WB incidence could be reduced by regulating gut microbiota and the potential mechanism that leads to decreased WB incidence.

Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres.

Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20-300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca2+-activated maximal (active) force (Fo) by about 50% and evoked an approximately 3-fold increase in Ca2+-independent (passive) force (Fpassive). Oxidation of sulfhydryl (SH) groups was detected in structural proteins (e.g., nebulin, α-actinin, meromyosin 2) and in contractile proteins (e.g., myosin heavy chain and myosin-binding protein C) as well as in titin in the presence of 300 µM heme. This SH oxidation was not reversed by dithiothreitol (50 mM). Sulfenic acid (SOH) formation was also detected in the structural proteins (nebulin, α-actinin, meromyosin). Heme effects on SH oxidation and SOH formation were prevented by hemopexin (Hpx) and α1-microglobulin (A1M). These data suggest that free heme has a significant impact on human skeletal muscle fibres, whereby oxidative alterations in structural and contractile proteins limit contractile function. This may explain and or contribute to the weakness and increase of skeletal muscle stiffness in chronic heart failure, rhabdomyolysis, and other hemolytic diseases. Therefore, therapeutic use of Hpx and A1M supplementation might be effective in preventing heme-induced skeletal muscle alterations.

A tissue-specific screen of ceramide expression in aged mice identifies ceramide synthase-1 and ceramide synthase-5 as potential regulators of fiber size and strength in skeletal muscle.

Loss of skeletal muscle mass is one of the most widespread and deleterious processes in aging humans. However, the mechanistic metabolic principles remain poorly understood. In the framework of a multi-organ investigation of age-associated changes of ceramide species, a unique and distinctive change pattern of C16:0 and C18:0 ceramide species was detected in aged skeletal muscle. Consistently, the expression of CerS1 and CerS5 mRNA, encoding the ceramide synthases (CerS) with substrate preference for C16:0 and C18:0 acyl chains, respectively, was down-regulated in skeletal muscle of aged mice. Similarly, an age-dependent decline of both CerS1 and CerS5 mRNA expression was observed in skeletal muscle biopsies of humans. Moreover, CerS1 and CerS5 mRNA expression was also reduced in muscle biopsies from patients in advanced stage of chronic heart failure (CHF) suffering from muscle wasting and frailty. The possible impact of CerS1 and CerS5 on muscle function was addressed by reversed genetic analysis using CerS1Δ/Δ and CerS5Δ/Δ knockout mice. Skeletal muscle from mice deficient of either CerS1 or CerS5 showed reduced caliber sizes of both slow (type 1) and fast (type 2) muscle fibers, fiber grouping, and fiber switch to type 1 fibers. Moreover, CerS1- and CerS5-deficient mice exhibited reduced twitch and tetanus forces of musculus extensor digitorum longus. The findings of this study link CerS1 and CerS5 to histopathological changes and functional impairment of skeletal muscle in mice that might also play a functional role for the aging skeletal muscle and for age-related muscle wasting disorders in humans.

Label-free identification of myopathological features with coherent anti-Stokes Raman scattering.

INTRODUCTION: The aim of this study was the label-free identification of distinct myopathological features with coherent anti-Stokes Raman scattering (CARS) imaging, which leaves the sample intact for further analysis. METHODS: The protein distribution was determined without labels by CARS at 2,930 cm-1 and was compared with the results of standard histological staining. RESULTS: CARS imaging allowed the visualization of glycogen accumulation in glycogen storage disease type 5 (McArdle disease) and of internal nuclei in centronuclear myopathy. CARS identified an inhomogeneous protein distribution within muscle fibers in sporadic inclusion body myositis that was not shown with standard staining. In Duchenne muscular dystrophy, evidence for a higher protein content at the border of hypercontracted fibers was detected. DISCUSSION: CARS enables the label-free identification of distinct myopathological features, possibly paving the way for subsequent proteomic, metabolic, and genomic analyses. Muscle Nerve 58: 457-460, 2018.