Perioperative Naltrexone Management: A Scoping Review by the Perioperative Pain and Addiction Interdisciplinary Network.

Substance use disorders, including alcohol use disorder, are a public health concern that affect more than 150 million people globally. The opioid antagonist naltrexone is being increasingly prescribed to treat opioid use disorder, alcohol use disorder, and chronic pain. Perioperative management of patients on naltrexone is inconsistent and remains a controversial topic, with mismanagement posing a significant risk to the long-term health of these patients. This scoping review was conducted to identify human studies in which the perioperative management of naltrexone was described. This review includes a systematic literature search involving Medline, Medline In-Process, Embase, PsycINFO, and Web of Science. Seventeen articles that describe perioperative naltrexone management strategies were included, including thirteen guidelines, one case report, and three randomized trials. Despite its use in patients with alcohol use disorder and chronic pain, no clinical studies, case reports, or guidelines addressed naltrexone use in these clinical populations. All of the guideline documents recommended the preoperative cessation of naltrexone, irrespective of dose, indication, or route of administration. None of these guideline documents were designed on the basis of a systematic literature search or a Delphi protocol. As described by the primary studies, perioperative pain relief varied depending on naltrexone dose and route of administration, time since last naltrexone administration, and underlying substance use disorder. None of the studies commented on the maintenance of recovery for the patient's substance use disorder in the context of perioperative naltrexone management. The current understanding of the risks and benefits of continuing or stopping naltrexone perioperatively is limited by a lack of high-quality evidence. In patients with risk factors for return to use of opioids or alcohol, the discontinuation of naltrexone should have a strong rationale. Future studies and guidelines should seek to address both acute pain management and maintaining recovery when discussing perioperative naltrexone management strategies.

Oxidized Low-Density Lipoprotein Accumulation in Macrophages Impairs Lipopolysaccharide-Induced Activation of AKT2, ATP Citrate Lyase, Acetyl-Coenzyme A Production, and Inflammatory Gene H3K27 Acetylation.

The accumulation of lipid and the formation of macrophage foam cells is a hallmark of atherosclerosis, a chronic inflammatory disease. To better understand the role of macrophage lipid accumulation in inflammation during atherogenesis, we studied early molecular events that follow the accumulation of oxidized low-density lipoprotein (oxLDL) in cultured mouse macrophages. We previously showed that oxLDL accumulation downregulates the inflammatory response in conjunction with downregulation of late-phase glycolysis. In this study, we show that within hours after LPS stimulation, macrophages with accumulated oxLDL maintain early-phase glycolysis but selectively downregulate activation of AKT2, one of three AKT isoforms. The inhibition of AKT2 activation reduced LPS-induced ATP citrate lyase activation, acetyl-CoA production, and acetylation of histone 3 lysine 27 (H3K27ac) in certain inflammatory gene promoters. In contrast to oxLDL, multiple early LPS-induced signaling pathways were inhibited in macrophages with accumulated cholesterol, including TBK1, AKT1, AKT2, MAPK, and NF-κB, and early-phase glycolysis. The selective inhibition of LPS-induced AKT2 activation was dependent on the generation of mitochondrial oxygen radicals during the accumulation of oxLDL in macrophages prior to LPS stimulation. This is consistent with increased oxidative phosphorylation, fatty acid synthesis, and oxidation pathways found by comparative transcriptomic analyses of oxLDL-loaded versus control macrophages. Our study shows a functional connection between oxLDL accumulation, inactivation of AKT2, and the inhibition of certain inflammatory genes through epigenetic changes that occur soon after LPS stimulation, independent of early-phase glycolysis.