The first knock-in rat model for glutaric aciduria type I allows further insights into pathophysiology in brain and periphery.

Glutaric aciduria type I (GA-I, OMIM # 231670) is an inborn error of metabolism caused by a deficiency of glutaryl-CoA dehydrogenase (GCDH). Patients develop acute encephalopathic crises (AEC) with striatal injury most often triggered by catabolic stress. The pathophysiology of GA-I, particularly in brain, is still not fully understood. We generated the first knock-in rat model for GA-I by introduction of the mutation p.R411W, the rat sequence homologue of the most common Caucasian mutation p.R402W, into the Gcdh gene of Sprague Dawley rats by CRISPR/CAS9 technology. Homozygous Gcdhki/ki rats revealed a high excretor phenotype, but did not present any signs of AEC under normal diet (ND). Exposure to a high lysine diet (HLD, 4.7%) after weaning resulted in clinical and biochemical signs of AEC. A significant increase of plasmatic ammonium concentrations was found in Gcdhki/ki rats under HLD, accompanied by a decrease of urea concentrations and a concomitant increase of arginine excretion. This might indicate an inhibition of the urea cycle. Gcdhki/ki rats exposed to HLD showed highly diminished food intake resulting in severely decreased weight gain and moderate reduction of body mass index (BMI). This constellation suggests a loss of appetite. Under HLD, pipecolic acid increased significantly in cerebral and extra-cerebral liquids and tissues of Gcdhki/ki rats, but not in WT rats. It seems that Gcdhki/ki rats under HLD activate the pipecolate pathway for lysine degradation. Gcdhki/ki rat brains revealed depletion of free carnitine, microglial activation, astroglyosis, astrocytic death by apoptosis, increased vacuole numbers, impaired OXPHOS activities and neuronal damage. Under HLD, Gcdhki/ki rats showed imbalance of intra-and extracellular creatine concentrations and indirect signs of an intracerebral ammonium accumulation. We successfully created the first rat model for GA-I. Characterization of this Gcdhki/ki strain confirmed that it is a suitable model not only for the study of pathophysiological processes, but also for the development of new ther-apeutic interventions. We further brought up interesting new insights into the pathophysiology of GA-I in brain and periphery

The first knock-in rat model for glutaric aciduria type I allows further insights into pathophysiology in brain and periphery

Glutaric aciduria type I (GA-I, OMIM # 231670) is an inborn error of metabolism caused by a deficiency of glutaryl-CoA dehydrogenase (GCDH). Patients develop acute encephalopathic crises (AEC) with striatal injury most often triggered by catabolic stress. The pathophysiology of GA-I, particularly in brain, is still not fully understood. We generated the first knock-in rat model for GA-I by introduction of the mutation p.R411W, the rat sequence homologue of the most common Caucasian mutation p.R402W, into the Gcdh gene of Sprague Dawley rats by CRISPR/CAS9 technology. Homozygous Gcdhki/ki rats revealed a high excretor phenotype, but did not present any signs of AEC under normal diet (ND). Exposure to a high lysine diet (HLD, 4.7%) after weaning resulted in clinical and biochemical signs of AEC. A significant increase of plasmatic ammonium concentrations was found in Gcdhki/ki rats under HLD, accompanied by a decrease of urea concentrations and a concomitant increase of arginine excretion. This might indicate an inhibition of the urea cycle. Gcdhki/ki rats exposed to HLD showed highly diminished food intake resulting in severely decreased weight gain and moderate reduction of body mass index (BMI). This constellation suggests a loss of appetite. Under HLD, pipecolic acid increased significantly in cerebral and extra-cerebral liquids and tissues of Gcdhki/ki rats, but not in WT rats. It seems that Gcdhki/ki rats under HLD activate the pipecolate pathway for lysine degradation. Gcdhki/ki rat brains revealed depletion of free carnitine, microglial activation, astroglyosis, astrocytic death by apoptosis, increased vacuole numbers, impaired OXPHOS activities and neuronal damage. Under HLD, Gcdhki/ki rats showed imbalance of intra- and extracellular creatine concentrations and indirect signs of an intracerebral ammonium accumulation. We successfully created the first rat model for GA-I. Characterization of this Gcdhki/ki strain confirmed that it is a suitable model not only for the study of pathophysiological processes, but also for the development of new therapeutic interventions. We further brought up interesting new insights into the pathophysiology of GA-I in brain and periphery

Methylprednisolone versus intravenous immunoglobulins in children with paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS): an open-label, multicentre, randomised trial

Background: the emergence of paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) led to the widespread use of anti-inflammatory treatments in the absence of evidence from randomised controlled trials (RCTs). We aimed to assess the effectiveness of intravenous methylprednisolone compared with intravenous immunoglobulins. Methods: this is an open-label, multicentre, two-arm RCT done at ten hospitals in Switzerland in children younger than 18 years hospitalised with PIMS-TS (defined as age &lt;18 years; fever and biochemical evidence of inflammation, and single or multiorgan dysfunction; microbiologically proven or putative contact with SARS-CoV-2; and exclusion of any other probable disease). Patients were randomly assigned 1:1 to intravenous methylprednisolone (10 mg/kg per day for 3 days) or intravenous immunoglobulins (2 g/kg as a single dose). The primary outcome was length of hospital stay censored at day 28, death, or discharge. Secondary outcomes included proportion and duration of organ support. Analyses were done by intention-to-treat. The study was registered with Swiss National Clinical Trials Portal (SNCTP000004720) and ClinicalTrials.gov (NCT04826588). Findings: between May 21, 2021, and April 15, 2022, 75 patients with a median age of 9·1 years (IQR 6·2–12·2) were included in the intention-to-treat population (37 in the methylprednisolone group and 38 in the intravenous immunoglobulins group). The median length of hospital stay was 6·0 days (IQR 4·0–8·0) in the methylprednisolone group and 6·0 days (IQR 5·0–8·8) in the intravenous immunoglobulins group (estimated effect size –0·037 of the log10 transformed times, 95% CI –0·13 to 0·065, p=0·42). Fewer patients in the methylprednisolone group (ten [27%] of 37) required respiratory support compared with the intravenous immunoglobulin group (21 [55%] of 38, p=0·025). Need and duration of inotropes, admission to intensive care units, cardiac events after baseline, and major bleeding and thrombotic events were not significantly different between the study groups. Interpretation: in this RCT, treatment with methylprednisolone in children with PIMS-TS did not significantly affect the length of hospital stay compared with intravenous immunoglobulins. Intravenous methylprednisolone could be an acceptable first-line treatment in children with PIMS-TS. Funding: NOMIS Foundation, Vontobel Foundation, and Gaydoul Foundation.</p

Cardiac assessment and inflammatory markers in children with paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV2 (PIMS-TS) treated with methylprednisolone versus intravenous immunoglobulins: 6-month follow-up outcomes of the randomised controlled Swissped RECOVERY trialResearch in context

Summary: Background: Previous findings from the Swissped RECOVERY trial showed that patients with Pediatric Inflammatory Multisystem Syndrome–Temporally Associated with SARS-CoV-2 (PIMS-TS) who were randomly assigned to intravenous immunoglobulins or methylprednisolone have a comparable length of hospital stay. Here, we report the 6-month follow-up outcomes of cardiac pathologies and normalisation of clinical or laboratory signs of inflammation from this study population. Methods: This pre-planned follow-up of patients with PIMS-TS included the Swissped RECOVERY Trial reports on the 6-month outcomes of the cohort after randomisation, with a focus on cardiac, haematological, and biochemical findings. The trial was an investigator-initiated randomised multicentre open-label two-arm trial in children and adolescents hospitalised with PIMS-TS at ten hospitals in Switzerland. Cardiological assessments and laboratory analyses were prospectively collected in the intention-to-treat analysis on pre-defined intervals after hospital discharge. Differences between randomised arms were investigated using Chi-square test for categorical and Wilcoxon test for continuous variables. The trial is registered with the Swiss National Clinical Trials Portal (SNCTP000004720) and ClinicalTrials.gov (NCT04826588). Findings: Between May 21, 2021 and April 15, 2022, 75 patients with a median age of 9.1 years (IQR 6.2–12.2) were included in the intention-to-treat population (37 in the methylprednisolone group and 38 in the intravenous immunoglobulin group). During follow-up, the incidence of abnormal left ventricular systolic function, coronary artery aneurysms (CAA), and other signs of inflammation were comparable in both groups. However, we detected cardiac abnormalities with low incidence and a mild degree grade of pathology. CAAs were observed in 2/38 children (5.3%) in the IVIG group and 1/37 children (2.7%) in the methylprednisolone group at 6-month follow-up (difference proportion 0.75; 95% confidence interval (CI) −0.05 to 1.0; p = 0.39). Interpretation: Methylprednisolone alone may be an acceptable first-line treatment as left ventricular systolic dysfunction and clinical/laboratory evidence for inflammation quickly resolved in all children. However, our findings need further confirmation through larger studies as our sample size is likely to be of insufficient power to address rare clinically relevant adverse outcomes. Funding: NOMIS, Vontobel, and Gaydoul Foundation