Perioperative Use of IgM-Enriched Immunoglobulins in Liver Transplantation Recipients at High Risk for Infections: A Preliminary Study

: Background: Infections frequently occur after orthotopic liver transplantation (OLT) and are associated with increased mortality. In 2018, we introduced perioperative administration of intravenous immunoglobulin enriched in IgM as an optional therapy in recipients at a high risk of infection. This preliminary study evaluated whether this preparation reduced infections in the early post-transplantation period. Methods: Adult patients with a high risk of postoperative infections who underwent OLT between January 2014 and December 2021 in our center were included in the study. The primary outcome was the occurrence of new postoperative bacterial and fungal infections within the first 30 days after OLT. Results: Ninety recipients at a high risk of postoperative infections who underwent OLT were included, of whom 51 (57%) received IgM preparation. Patients treated and not treated with IgM were similar in terms of demographics, model of end-stage liver disease score, and risk factors for postoperative infections. The occurrence of new infections was lower (absolute risk reduction (ARR) 21.2%; p = 0.038) in patients who received IgM than in those who did not. Multivariate analysis adjusted for confounders (OR 0.348; p = 0.033) and propensity score-based matching analysis (ARR 21.2%, p = 0.067) confirmed an association between IgM preparation and lower occurrence of postoperative infections. The 90-day mortality rate was lower (ARR 13.4%, p = 0.018) in patients who received IgM preparation. Conclusions: In OLT recipients at high risk for infections, perioperative administration of an IgM-enriched preparation seems to reduce the development of new infections within the first 30 days after OLT

The novel adrenergic agonist ATR-127 targets skeletal muscle and brown adipose tissue to tackle diabesity and steatohepatitis

ObjectiveSimultaneous activation of β2- and β3-adrenoceptors (ARs) improves whole-body metabolism via beneficial effects in skeletal muscle and brown adipose tissue (BAT). Nevertheless, high-efficacy agonists simultaneously targeting these receptors whilst limiting activation of β1-ARs – and thus inducing cardiovascular complications – are currently non-existent. Therefore, we here developed and evaluated the therapeutic potential of a novel β2-and β3-AR, named ATR-127, for the treatment of obesity and its associated metabolic perturbations in preclinical models.MethodsIn the developmental phase, we assessed the impact of ATR-127's on cAMP accumulation in relation to the non-selective β-AR agonist isoprenaline across various rodent β-AR subtypes, including neonatal rat cardiomyocytes. Following these experiments, L6 muscle cells were stimulated with ATR-127 to assess the impact on GLUT4-mediated glucose uptake and intramyocellular cAMP accumulation. Additionally, in vitro, and in vivo assessments are conducted to measure ATR-127's effects on BAT glucose uptake and thermogenesis. Finally, diet-induced obese mice were treated with 5 mg/kg ATR-127 for 21 days to investigate the effects on glucose homeostasis, body weight, fat mass, skeletal muscle glucose uptake, BAT thermogenesis and hepatic steatosis.ResultsExposure of L6 muscle cells to ATR-127 robustly enhanced GLUT4-mediated glucose uptake despite low intramyocellular cAMP accumulation. Similarly, ATR-127 markedly increased BAT glucose uptake and thermogenesis both in vitro and in vivo. Prolonged treatment of diet-induced obese mice with ATR-127 dramatically improved glucose homeostasis, an effect accompanied by decreases in body weight and fat mass. These effects were paralleled by an enhanced skeletal muscle glucose uptake, BAT thermogenesis, and improvements in hepatic steatosis.ConclusionsOur results demonstrate that ATR-127 is a highly effective, novel β2- and β3-ARs agonist holding great therapeutic promise for the treatment of obesity and its comorbidities, whilst potentially limiting cardiovascular complications. As such, the therapeutic effects of ATR-127 should be investigated in more detail in clinical studies

Activation of GPR55 Receptors Exacerbates oxLDL-Induced Lipid Accumulation and Inflammatory Responses, while Reducing Cholesterol Efflux from Human Macrophages

<div><p>The G protein-coupled receptor GPR55 has been proposed as a new cannabinoid receptor associated with bone remodelling, nervous system excitability, vascular homeostasis as well as in several pathophysiological conditions including obesity and cancer. However, its physiological role and underlying mechanism remain unclear. In the present work, we demonstrate for the first time its presence in human macrophages and its increased expression in ox-LDL-induced foam cells. In addition, pharmacological activation of GPR55 by its selective agonist O-1602 increased CD36- and SRB-I-mediated lipid accumulation and blocked cholesterol efflux by downregulating ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, as well as enhanced cytokine- and pro-metalloprotease-9 (pro-MMP-9)-induced proinflammatory responses in foam cells. Treatment with cannabidiol, a selective antagonist of GPR55, counteracted these pro-atherogenic and proinflammatory O-1602-mediated effects. Our data suggest that GPR55 could play deleterious role in ox-LDL-induced foam cells and could be a novel pharmacological target to manage atherosclerosis and other related cardiovascular diseases.</p></div

mRNA and protein analysis of GPR55 in human macrophages and foam cells.

<p>Human THP-1 macrophages (MΦ) were left untreated or were treated for 18 h with 100 μg/ml oxLDL to generate foam cells (FC). (A) mRNA content of GPR55 was analyzed by qRT-PCR. Data are shown as mean (±SD) of five independent experiments, each in duplicate. (B) Western blot analysis of GPR55, with the expected molecular mass of each protein shown on the left-hand side. Data are expressed in comparison with β-actin, and are the mean (± SD) of five independent experiments, each performed in duplicate. *p<0.05 <i>versus</i> MΦ. (C) Immunofluorescence of GPR55 was performed by confocal laser-scanning microscopy, and data are shown as pictures taken with a 63 objective (numerical aperture 1⁄4 1.4), and as densitometric analysis (mean ±SD) of at least six independent experiments. (D) GPR55 expression was assessed by flow cytometry upon staining cells with anti-GPR55 FITC either at cell surface or intracellularly upon cell permeabilization. Data are reported as mean fluorescence intensity (M.I.F.), and are representative of five independent experiments. *p<0.05 <i>versus</i> MΦ.</p

Effect of GPR55 activation on NFAT transcription factor members.

<p>Human THP-1 macrophages (MΦ) were left untreated or were treated for 18 h with 100 μg/ml oxLDL to generate foam cells (FC). FC were treated for 24h with O-1602, and pre-treated or not with CDB. mRNA analysis of NFAT members was performed by qRT-PCR. Data are shown as mean ± SD of three independent experiments, each in duplicate. *p<0.05 <i>versus</i> FC; #p<0.05 <i>versus</i> FC+O-1602.</p

Effect of GPR55 activation on MMP-9 activity.

<p>Human THP-1 macrophages (MΦ) were left untreated or were treated for 18 h with 100 μg/ml oxLDL to generate foam cells (FC). FC were treated for 24h with O-1602, and pretreated or not with CDB. After the treatments, surnatants were collected and gelatinase activity of MMP-9 was measured in conditioned media subjected to zymography. Gelatinase activity is expressed as area (mm²) exposed to MMP-9 activity. Data are shown as mean ± SD of five independent experiments. *p<0.05 <i>versus</i> FC; #p<0.05 <i>versus</i> FC+O-1602.</p

Regulation of lipid-droplets accumulation and cholesterol transporters in human macrophages and foam cells.

<p>Human THP-1 macrophages (MΦ) were left untreated or were treated for 18 h with 100 μg/ ml oxLDL to generate foam cells (FC), that were then treated for further 24 h with selective GPR55 agonist O-1602, and were pretreated or not with the CBD antagonist. (A) Nile red-stained lipid droplets were analyzed by confocal laser-scanning microscopy, and data are shown as numbers of lipid-droplets per cell (mean ±SD) of at least six independent experiments. Representative images of MΦ and FC, as well as of FC treated with 10nM O-1602or 0.5 μM CBD are shown in the panel. *p<0.05<i>versus</i> MΦ; #p<0.05 <i>versus</i>FC+O-1602. (B) Effect of GPR55 activation on CD36 expression in human macrophages and foam cells. The latter cells were pretreated with the CBD antagonist, and then were treated with the O-1602 agonist. CD36 expression was assessed by flow cytometry upon staining cells with anti-CD36 FITC. Data are reported as mean fluorescence intensity, and are representative of four independent experiments. Western blot analysis of SR-BI (C), ABCA1 (D), ABCG1 (E), with the expected molecular mass of each protein shown on the left-hand side. Data are expressed in comparison with β-actin, and are the mean (±SD) of five independent experiments, each performed in duplicate. *p<0.05 <i>versus</i> MΦ; #p<0.05 <i>versus</i> FC+O-1602.</p