84 research outputs found

    Chronic Muscle Weakness and Mitochondrial Dysfunction in the Absence of Sustained Atrophy in a Preclinical Sepsis Model

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    Chronic critical illness is a global clinical issue affecting millions of sepsis survivors annually. Survivors report chronic skeletal muscle weakness and development of new functional limitations that persist for years. To delineate mechanisms of sepsis-induced chronic weakness, we first surpassed a critical barrier by establishing a murine model of sepsis with ICU-like interventions that allows for the study of survivors. We show that sepsis survivors have profound weakness for at least 1 month, even after recovery of muscle mass. Abnormal mitochondrial ultrastructure, impaired respiration and electron transport chain activities, and persistent protein oxidative damage were evident in the muscle of survivors. Our data suggest that sustained mitochondrial dysfunction, rather than atrophy alone, underlies chronic sepsis-induced muscle weakness. This study emphasizes that conventional efforts that aim to recover muscle quantity will likely remain ineffective for regaining strength and improving quality of life after sepsis until deficiencies in muscle quality are addressed

    Genome-wide parent-of-origin DNA methylation analysis reveals the intricacies of human imprinting and suggests a germline methylation-independent mechanism of establishment

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    Differential methylation between the two alleles of a gene has been observed in imprinted regions, where the methylation of one allele occurs on a parent-of-origin basis, the inactive X-chromosome in females, and at those loci whose methylation is driven by genetic variants. We have extensively characterized imprinted methylation in a substantial range of normal human tissues, reciprocal genome-wide uniparental disomies, and hydatidiform moles, using a combination of whole-genome bisulfite sequencing and high-density methylation microarrays. This approach allowed us to define methylation profiles at known imprinted domains at base-pair resolution, as well as to identify 21 novel loci harboring parent-of-origin methylation, 15 of which are restricted to the placenta. We observe that the extent of imprinted differentially methylated regions (DMRs) is extremely similar between tissues, with the exception of the placenta. This extra-embryonic tissue often adopts a different methylation profile compared to somatic tissues. Further, we profiled all imprinted DMRs in sperm and embryonic stem cells derived from parthenogenetically activated oocytes, individual blastomeres, and blastocysts, in order to identify primary DMRs and reveal the extent of reprogramming during preimplantation development. Intriguingly, we find that in contrast to ubiquitous imprints, the majority of placenta-specific imprinted DMRs are unmethylated in sperm and all human embryonic stem cells. Therefore, placental-specific imprinting provides evidence for an inheritable epigenetic state that is independent of DNA methylation and the existence of a novel imprinting mechanism at these loci

    Increased expression of phosphorylated forms of RNA-dependent protein kinase and eukaryotic initiation factor 2α may signal skeletal muscle atrophy in weight-losing cancer patients

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    Previous studies suggest that the activation (autophosphorylation) of dsRNA-dependent protein kinase (PKR) can stimulate protein degradation, and depress protein synthesis in skeletal muscle through phosphorylation of the translation initiation factor 2 (eIF2) on the α-subunit. To understand whether these mediators are important in muscle wasting in cancer patients, levels of the phospho forms of PKR and eIF2α have been determined in rectus abdominus muscle of weight losing patients with oesophago-gastric cancer, in comparison with healthy controls. Levels of both phospho PKR and phospho eIF2α were significantly enhanced in muscle of cancer patients with weight loss irrespective of the amount and there was a linear relationship between phosphorylation of PKR and phosphorylation of eIF2α (correlation coefficient 0.76, P=0.005). This suggests that phosphorylation of PKR led to phosphorylation of eIF2α. Myosin levels decreased as the weight loss increased, and there was a linear relationship between myosin expression and the extent of phosphorylation of eIF2α (correlation coefficient 0.77, P=0.004). These results suggest that phosphorylation of PKR may be an important initiator of muscle wasting in cancer patients

    Effect of Cholecalciferol Supplementation on Vitamin D Status and Cathelicidin Levels in Sepsis: A Randomized, Placebo-Controlled Trial

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    To compare changes in vitamin D status and cathelicidin (LL-37) levels in septic ICU patients treated with placebo versus cholecalciferol. Design: Randomized, placebo-controlled, trial. Setting: Medical and surgical ICUs of a single teaching hospital in Boston, MA. Patients: Thirty adult ICU patients. Interventions: Placebo (n = 10) versus 200,000 IU cholecalciferol (n = 10) versus 400,000 IU cholecalciferol (n = 10), within 24 hours of new-onset severe sepsis or septic shock. Measurements and Main Results: Blood samples were obtained at baseline (day 1) and on days 3, 5, and 7, to assess total 25-hydroxyvitamin D, as well as vitamin D-binding protein and albumin to calculate bioavailable 25-hydroxyvitamin D. Plasma LL-37 and high-sensitivity C-reactive protein levels were also measured. At baseline, median (interquartile range) plasma 25-hydroxyvitamin D was 17 ng/mL (13-22 ng/mL) and peaked by day 5 in both intervention groups. Groups were compared using Kruskal-Wallis tests. Relative to baseline, on day 5, median change in biomarkers for placebo, 200,000 IU cholecalciferol, and 400,000 IU cholecalciferol groups, respectively, were as follows: 1) total 25-hydroxyvitamin D, 3% (-3% to 8%), 49% (30-82%), and 69% (55-106%) (p < 0.001); 2) bioavailable 25-hydroxyvitamin D, 4% (-8% to 7%), 45% (40-70%), and 96% (58-136%) (p < 0.01); and 3) LL-37:-17% (-9% to-23%), 4% (-10% to 14%), and 30% (23-48%) (p = 0.04). Change in high-sensitivity C-reactive protein levels did not differ between groups. A positive correlation was observed between bioavailable 25-hydroxyvitamin D and LL-37 (Spearman \u3c1 = 0.44; p = 0.03) but not for total 25-hydroxyvitamin D and LL-37. Conclusions: High-dose cholecalciferol supplementation rapidly and safely improves 25-hydroxyvitamin D and bioavailable 25-hydroxyvitamin D levels in patients with severe sepsis or septic shock. Changes in bioavailable 25-hydroxyvitamin D are associated with concomitant increases in circulating LL-37 levels. Larger trials are needed to verify these findings and to assess whether optimizing vitamin D status improves sepsis-related clinical outcomes

    IFPA Meeting 2012 Workshop Report III: trophoblast deportation, gestational trophoblastic disease, placental insufficiency and fetal growth restriction, trophoblast over-invasion and accreta-related pathologies, placental thrombosis and fibrinolysis.

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    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of clinical research and pregnancy disorders: 1) trophoblast deportation; 2) gestational trophoblastic disease; 3) placental insufficiency and fetal growth restriction; 4) trophoblast overinvasion and accreta-related pathologies; 5) placental thrombosis and fibrinolysis

    Preoperative identification of synchronous ovarian and endometrial cancers: the importance of appropriate workup

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    Item does not contain fulltextOBJECTIVE: For treatment of patients with both endometrial and ovarian cancer, it is important to discriminate between 2 primary tumors and metastatic disease. Currently, criteria are based on postoperative findings. The aim of this study was to determine whether clinical parameters can discriminate between these groups preoperatively and whether a practical guideline could improve appropriate workup and treatment. METHODS: A total of 45 patients with a diagnosis of both endometrium and ovarian cancer between 1998 and 2009 and were included for analysis. Clinical and pathological data were obtained, and initial CA-125 was registered; patients had a diagnosis of 2 primary tumors or tumors with metastasis. All patients were reclassified according to workup and treatment. RESULTS: Patients with synchronous primary tumors were significantly younger, presented more often with abnormal uterine bleeding, and had a lower initial CA-125 than both metastatic groups (P < 0.05). With age and CA-125 included in a polytomic logistic regression model, 83.3% of diagnoses could be classified correctly. In 15 of 17 patients presented with adnexal mass, workup was incomplete owing to lack on information of the endometrial status. In patients presenting with abnormal uterine bleeding, 13 of 21 patients had an incomplete workup leading to staging laparotomy secondary to initial surgical treatment in 2 patients. CONCLUSIONS: Patients with synchronous endometrial and ovarian cancers are young, often present with abnormal uterine bleeding and have a low initial CA-125. Adequate workup with attention to both ovarian and endometrial status, especially in young patients with a wish to preserve fertility, is important to make the right decision for treatment
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