Anti-CD14 monoclonal antibody, clone UCHM1 [APC]

BackgroundNatural products may provide a source for the discovery and development of adjunctive pharmacological interventions to modulate the inflammatory pathways contributing to chronic disease. Xanthohumol, a flavonoid from the hops plant (Humulus lupulus), has antioxidant and anti-inflammatory properties and may act as a prebiotic to the intestinal microbiota. Xanthohumol is not currently approved as a drug by the US Food and Drug Administration (FDA), but is available as a dietary supplement and ingredient in medical foods. To formally test the safety of xanthohumol, a phase I clinical trial ("XMaS") was designed and approved under an Investigational New Drug application to the US FDA. The main objective is to examine the clinical safety and subjective tolerability of xanthohumol in healthy adults compared to placebo. Additional aims are to monitor biomarkers related to inflammation, gut permeability, bile acid metabolism, routes, and in vivo products of xanthohumol metabolism, and to evaluate xanthohumol's impact on gut microbial composition.MethodsThe safety and tolerability of xanthohumol in healthy adults will be evaluated in a triple-masked, randomized, placebo-controlled trial. Participants will be randomized to either 24mg/day of xanthohumol or placebo for 8 weeks. Blood cell counts, hepatic and renal function tests, electrolytes, and self-reported health-related quality of life measures will be collected every 2 weeks. Participants will be queried for adverse events throughout the trial. Xanthohumol metabolites in blood, urine, and stool will be measured. Biomarkers to be evaluated include plasma tumor necrosis factor-alpha, various interleukins, soluble CD14, lipopolysaccharide-binding protein, fecal calprotectin, and bile acids to assess impact on inflammatory and gut permeability-related mechanisms in vivo. Stool samples will be analyzed to determine effects on the gut microbiome.DiscussionThis phase I clinical trial of xanthohumol will assess safety and tolerability in healthy adults, collect extensive biomarker data for assessment of potential mechanism(s), and provide comparison data necessary for future phase II trials in chronic disease(s). The design and robustness of the planned safety and mechanistic evaluations planned provide a model for drug discovery pursuits from natural products.Trial registrationClinicalTrials.gov NCT03735420. Registered on November 8, 2018

Rationale: Exposure to high catecholamine levels is associated with inflammatory changes of myeloid cells and atherosclerosis, but the underlying mechanisms are only partly understood. Objective: To investigate whether the proinflammatory effects of noradrenaline and adrenaline can, in part, be explained by the induction of an immunologic memory in innate immune cells, termed trained immunity. Methods and Results: In vitro, we exposed human primary monocytes to (nor)adrenaline for 24 hours, after which cells were rested and differentiated to macrophages over 5 days. After restimulation with lipopolysaccharide on day 6, (nor)adrenaline-exposed cells showed increased TNF-alpha (tumor necrosis factor-alpha) production. This coincided with an increase in glycolysis and oxidative phosphorylation measured with Seahorse technology on day 6 before restimulation. Inhibition of the beta-adrenoreceptor-cAMP signaling pathway prevented the induction of training. In vivo, we studied the functional, transcriptional, and epigenetic impact of peak-wise exposure to high catecholamine levels on monocytes isolated from pheochromocytoma/paraganglioma (PHEO) patients. In PHEO patients (n=10), the peripheral blood cell composition showed a myeloid bias and an increase of the inflammatory CD14++CD16+ (cluster of differentiation) intermediate monocyte subset compared with controls with essential hypertension (n=14). Ex vivo production of proinflammatory cytokines was higher in PHEO patients. These inflammatory changes persisted for 4 weeks after surgical removal of PHEO. Transcriptome analysis of circulating monocytes at baseline showed various differentially expressed genes in inflammatory pathways in PHEO patients; epigenetic profiling of the promoters of these genes suggests enrichment of the transcriptionally permissive chromatin mark H3K4me3 (trimethylation of lysine 4 on histone H3), indicative of in vivo training. Conclusions: Catecholamines induce long-lasting proinflammatory changes in monocytes in vitro and in vivo, indicating trained immunity. Our data contribute to the understanding of pathways driving inflammatory changes in conditions characterized by high catecholamine levels and propose that trained immunity underlies the increased cardiovascular event rate in PHEO patients.