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Pulmonary arterial hypertension (PAH) is a progressive disease of the pulmonary vasculature that leads to right ventricular failure. Skeletal muscle maladaptations limit physical activity and may contribute to disease progression. The role of alarmin/inflammatory signaling in PAH respiratory muscle dysfunction is unknown. We hypothesized that diaphragm mitochondrial and contractile functions are impaired in SU5416/hypoxia-induced pulmonary hypertension due to increased systemic IL-33 signaling. We induced pulmonary hypertension in adult C57Bl/6 J (WT) and ST2 (IL1RL1) gene ablated mice by SU5416/hypoxia (SuHx). We measured diaphragm fiber mitochondrial respiration, inflammatory markers, and contractile function ex vivo. SuHx reduced coupled and uncoupled permeabilized myofiber respiration by ∼40 %. During coupled respiration with complex I substrates, ST2 -/- attenuated SuHx inhibition of mitochondrial respiration (genotype × treatment interaction F[1,67] = 3.3, p = 0.07, η 2  = 0.04). Flux control ratio and coupling efficiency were not affected by SuHx or genotype. A higher substrate control ratio for succinate was observed in SuHx fibers and attenuated in ST2 -/- fibers (F[1,67] = 5.3, p < 0.05, η 2  = 0.07). Diaphragm TNFα, but not IL-33 or NFkB, was increased in SuHx vs. DMSO in both genotypes (F[1,43] = 4.7, p < 0.05, η 2  = 0.1). Diaphragm force-frequency relationships were right-shifted in SuHx vs. WT (F[3,440] = 8.4, p < 0.05, η 2  = 0.0025). There was no effect of ST2 -/- on the force-frequency relationship. Force decay during a fatigue protocol at 100 Hz, but not at 40 Hz, was attenuated by SuHx vs. DMSO in both genotypes (F[1,41] = 5.6, p < 0.05, η 2  = 0.11). SuHx mice exhibit a modest compensation in diaphragm contractility and mitochondrial dysfunction during coupled respiration; the latter partially regulated through ST2 signaling., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: To describe clinical, radiological and treatment characteristics in pediatric patients with SLS., Material and Methods: This is a descriptive and retrospective study in patients under 16 years old with the diagnosis of SLE complicated by SLS at the General Hospital. National Medical Center La Raza. Clinical, radiological and treatment variables were analyzed. Results are shown in frequencies and percentages., Results: Data from 11 patients, 9 females and 2 males were collected. Mean age at diagnosis of SLS was 12.2 years. Age at diagnosis of SLE was 11.1 years. SLEDAI 17.3. Renal desease 72%, hematological 91%, lymphopenia 63%, mucocutaneous 72%, neurological 9%, arthritis 54%, serositis 91%, fever 81%, secondary antiphospholipid syndrome, low C3 72%, low C4 81%, positive ANA 91%, positive anti-DNA 91%. Regarding clinical manifestations of SLE: cough 81%, dyspnea 91%, hipoxemia 81%, pleuritic pain 71%, average oxygen saturation 83%. Chest X-rays findings: right hemidiaphragm affection 18%, left 63%, bilateral 18%. Elevated hemidiaphragm 91%, atelectasis 18%, pleural effusion 91%, over one third of the cardiac silhouette under the diphragm 36%, bulging diaphragm 45%, 5th. anterior rib that crosses over the diaphragm 91%. M-mode ultrasound: diaphragmatic hypomotility 100%, pleural effusion 63%. Pulmonary function tests: restrictive pattern in 45% of the cases. Treatment was with supplementary oxygen 100%, intubation 18%, antibiotics 100%, steroids 100%, intravenous immunoglobulin 54%, plasmapheresis 18%, cyclophosphamide 54% and rituximab 18%. The clinical course was favorable in 81%., Conclusions: SLS should be suspected in patients with SLE and active disease who present hipoxemia, pleuritic pain, cough, dyspnea, pleural effusion and signs of restriction on chest X-rays. Therefore, a diaphragmatic M-mode ultrasound should be performed in order to establish the diagnosis.