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Muscle stem cells (MuSCs) enable muscle growth and regeneration after exercise or injury, but how metabolism controls their regenerative potential is poorly understood. We describe that primary metabolic changes can determine murine MuSC fate decisions. We found that glutamine anaplerosis into the tricarboxylic acid (TCA) cycle decreases during MuSC differentiation and coincides with decreased expression of the mitochondrial glutamate deaminase GLUD1. Deletion of Glud1 in proliferating MuSCs resulted in precocious differentiation and fusion, combined with loss of self-renewal in vitro and in vivo. Mechanistically, deleting Glud1 caused mitochondrial glutamate accumulation and inhibited the malate-aspartate shuttle (MAS). The resulting defect in transporting NADH-reducing equivalents into the mitochondria induced compartment-specific NAD + /NADH ratio shifts. MAS activity restoration or directly altering NAD + /NADH ratios normalized myogenesis. In conclusion, GLUD1 prevents deleterious mitochondrial glutamate accumulation and inactivation of the MAS in proliferating MuSCs. It thereby acts as a compartment-specific metabolic brake on MuSC differentiation., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction and Importance: Spontaneous coronary artery dissection is a rare cause of acute coronary syndromes not related to atherosclerosis. It involves the sudden tearing of the coronary artery wall, separating the inner intimal lining from the outer vessel wall, typically affecting a single coronary vessel. In 20% of cases, the cause of spontaneous coronary artery dissection is unknown. The other cases often occur in pregnant or postpartum women or in individuals with conditions such as connective tissue disorders or vasculitis., Case Presentation: Here, we describe a case of a 69-year-old African female presenting with non-ST-segment elevation myocardial infarction. Coronary angiography revealed an unusual triple-vessel spontaneous coronary artery dissection affecting peripheral segments, with further investigations suggesting polyarteritis nodosa., Conclusion: While triple-vessel spontaneous coronary artery dissection and polyarteritis nodosa (PAN) are individually rare, their coexistence is exceptionally uncommon and presents diagnostic and therapeutic challenges. Clinicians should be alert to vasculitic causes in patients with spontaneous coronary artery dissection, especially with atypical clinical features., (© 2024. The Author(s).)

Bone marrow aplasia is a rare and serious hematologic disorder. Although benign, it is a hematologic disorder whose prognosis can be poor and whose spontaneous development can be fatal. Treatment is long, difficult and costly. In developing countries, the mortality rate is high due to the difficulties of therapeutic management, both supportive and specific. We conducted a retrospective study of 92 cases of AM identified in the Pediatric Hematology and Oncology Department of the 20 Août University Hospital in Casablanca over a 10-year period (January 2010-January 2020). In this work, we present an overview of the situation and highlight the difficulties encountered in the management of AM in the Pediatric Hematology and Oncology Department of the University Hospital of Casablanca. In our study, the mean age was 19 years, ranging from 3 months to 29 years, with a peak in the 15-20 age group. The sex ratio (M/F) was 2.06, with a male predominance of 67%. In our series, only 35% of patients had complete bone marrow failure. An anemic syndrome was present in 92% of patients, and hemorrhagic and infectious syndromes were present in 70% and 41% of patients, respectively. The median time from diagnosis to treatment was 82 days. According to the Camitta score, 31% of our patients had mild AM, 41% had severe AM, and 28% had very severe AM. After etiologic evaluation, we concluded that 90% of the patients had idiopathic bone marrow aplasia, 2% had constitutional bone marrow aplasia, and 8% of the patients were suspected to have secondary bone marrow aplasia: post-hepatitis (3 cases), toxic (2 cases), drug-induced (1 case), and aplastic PNH (1 case). Mortality in the first three months after diagnosis was 21%. Sixty-nine percent of our patients received specific treatment: 28 were treated with cyclosporin (CIS) alone as first-line therapy, 20 received a combination of antilymphocyte serum (ALS) and cyclosporin, 2 received hematopoietic stem cell transplantation (HSCT), while 3 were treated with androgens alone. The overall response rate was 30% with CIS, 42% with ALS+CIS and 100% with HSCT. In our study, the overall death rate was 44%, while the one-year survival rate was 40%. It is important to note that septic shock was the leading cause of death (53% of deaths), followed by hemorrhagic shock (24%). This highlights the lack of hemodynamic resuscitation and symptomatic treatment. Our multivariate study defined the following risk factors as predictive of worse survival: age greater than 16 years (RR: 3.28; CI: 1.29-8.33; P=0.012), PNN less than 200 or very severe bone marrow aplasia (RR: 3.01; 1.1-8.08; P=0.028), and failure to receive any specific treatment (RR: 4.07; 1.77-9.35; P=0.0003). The high overall mortality in our series was due to several factors: inaccessibility to effective therapies, delayed diagnosis, failure to initiate specific treatment, inadequate symptomatic treatment, and geographical and financial inaccessibility., (Copyright © 2024 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Objective: Phase-shift contrast agents consist of a liquid perfluorocarbon core that can be vaporized by ultrasound to generate echogenic contrast with excellent spatiotemporal control. The purpose of the present work was to evaluate the in vitro and in vivo behavior of condensed lipid-shelled nanodroplets (NDs) using different analytical procedures., Methods: Perfluorobutane NDs were prepared by condensation of precursor fluorescently labeled lipid-shelled microbubbles (MBs) and were characterized in terms of size distribution, gas core content and in vitro stability in blood, as well as for their acoustic vaporization behavior using a custom-made setup. In particular, the in vivo behavior of the NDs was thoroughly investigated after intravenous bolus injection in rats. To this end, we report, for the first time, the efficient use of three complementary detection procedures to assess the in vivo persistence of NDs: (i) ultrasound contrast imaging of vaporized NDs, (ii) gas chromatography-mass spectrometry to determine the perfluorobutane core content and (iii) fluorescence intensity measurement in the collected blood samples., Results: The Coulter Counter Multisizer results confirmed the size distribution shift post-condensation. Furthermore, similar PFB concentrations from MB and ND suspensions were obtained, indicating an exceptionally low rate of MB breakage and spontaneous nanodroplet vaporization. As expected, these nanoscale droplets have longer circulation times compared with clinically approved MBs, and only slight variations in half-life were observed between the three monitoring procedures. Finally, echogenic signal observed in focal areas of the liver and spleen after vaporization was confirmed by accumulation of fluorescent nanodroplets in these organs., Conclusion: These results further contribute to our understanding of both the in vitro and in vivo behavior of sono-responsive nanodroplets, which is key to enabling efficient clinical translation., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2024 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)