The Impact of Acute Ingestion of a Ketone Monoester Drink on LPS-Stimulated NLRP3 Activation in Humans with Obesity

Nutrients. 2020 Mar 23;12(3):854. doi: 10.3390/nu12030854.

Abstract

Activation of the NOD-like receptor pyrin-domain containing 3 (NLRP3) inflammasome is associated with chronic low-grade inflammation in metabolic diseases such as obesity. Mechanistic studies have shown that β-hydroxybutyrate (OHB) attenuates activation of NLRP3, but human data are limited. In a randomized, double-blind, placebo-controlled crossover trial (n = 11) we tested the hypothesis that acutely raising β-OHB by ingestion of exogenous ketones would attenuate NLRP3 activation in humans with obesity. Blood was sampled before and 30 min post-ingestion of a ketone monoester drink ((R)-3-hydroxybutyl (R)-3-hydroxybutyrate, 482 mg/kg body mass) or placebo. A 75 g oral glucose load was then ingested, and a third blood sample was obtained 60 min following glucose ingestion. NLRP3 activation was quantified by assessing monocyte caspase-1 activation and interleukin (IL)-1β secretion in ex vivo lipopolysaccharide (LPS)-stimulated whole-blood cultures. LPS-stimulated caspase-1 activation increased following glucose ingestion (main effect of time; p = 0.032), with no differences between conditions. IL-1β secretion did not differ between conditions but was lower 60 min post-glucose ingestion compared to the fasting baseline (main effect of time, p = 0.014). Plasma IL-1β was detectable in ~80% of samples and showed a decrease from fasting baseline to 60 min in the ketone condition only (condition × time interaction, p = 0.01). In individuals with obesity, an excursion into hyperglycemia following ingestion of a glucose load augments LPS-induced activation of caspase-1 in monocytes with no apparent impact of raising circulating β-OHB concentration via ingestion of exogenous ketones. Exogenous ketone supplementation may impact plasma IL-1β, but these findings require confirmation in studies with larger sample sizes.

Keywords: 3-hydroxybutyric Acid; NLR family; beta-hydroxybutyrate; caspase-1; immunometabolism; inflammasome; inflammation; interleukin-1β; ketones; obesity; pyrin domain containing-3 protein.

MeSH terms

  • 3-Hydroxybutyric Acid / administration & dosage*
  • 3-Hydroxybutyric Acid / metabolism
  • 3-Hydroxybutyric Acid / pharmacology*
  • Adult
  • Aged
  • Caspase 1 / metabolism
  • Dietary Supplements*
  • Double-Blind Method
  • Eating
  • Female
  • Humans
  • Inflammasomes / metabolism*
  • Interleukin-1beta / metabolism
  • Lipopolysaccharides
  • Male
  • Middle Aged
  • Monocytes / metabolism
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism*
  • Obesity / metabolism*

Substances

  • IL1B protein, human
  • Inflammasomes
  • Interleukin-1beta
  • Lipopolysaccharides
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • NLRP3 protein, human
  • Caspase 1
  • 3-Hydroxybutyric Acid