Resveratrol improves ex vivo mitochondrial function but does not affect insulin sensitivity or brown adipose tissue in first degree relatives of patients with type 2 diabetes

Abstract

Objective: Resveratrol supplementation improves metabolic health in healthy obese men, but not in patients with type 2 diabetes (T2D) when given as add-on therapy. Therefore, we examined whether resveratrol can enhance metabolic health in men at risk of developing T2D. Additionally, we examined if resveratrol can stimulate brown adipose tissue (BAT).

Methods: Thirteen male first degree relatives (FDR) of patients with T2D received resveratrol (150 mg/day) and placebo for 30 days in a randomized, placebo controlled, cross-over trial.

Results: Resveratrol significantly improved ex vivo muscle mitochondrial function on a fatty acid-derived substrate. However, resveratrol did not improve insulin sensitivity, expressed as the rate of glucose disposal during a two-step hyperinsulinemic-euglycemic clamp. Also, intrahepatic and intramyocellular lipid content, substrate utilization, energy metabolism, and cold-stimulated 18F-FDG glucose uptake in BAT (n = 8) remained unaffected by resveratrol. In vitro experiments in adipocytes derived from human BAT confirmed the lack of effect on BAT.

Conclusions: Resveratrol stimulates muscle mitochondrial function in FDR males, which is in concordance with previous results. However, no other metabolic benefits of resveratrol were found in this group. This could be attributed to subject characteristics causing alterations in metabolism of resveratrol and thereby affecting resveratrol's effectiveness. CLINICALTRIALS.

Gov id: NCT02129595.

Keywords: Brown adipose tissue; Insulin sensitivity; Mitochondrial function; Pre-diabetes; Resveratrol; Type 2 diabetes.

Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

Figures

Graphical abstract

Figure 1

Total plasma resveratrol (RSV) and dihydro-resveratrol (DHR) values during the 30 days of resveratrol treatment period. Data are presented as mean ± SEM (n = 13).

Figure 2

Effect of resveratrol (RSV) on peripheral and hepatic insulin sensitivity. After 30 days of resveratrol and placebo, peripheral and hepatic insulin sensitivity were assessed by a two-step hyperinsulinemic-euglycemic clamp (t = 0–120 min: D-[6,6-2H2]glucose tracer infusion; t = 120–300 min: low-insulin infusion; t = 300–420 min: high-insulin infusion). Insulin-stimulated glucose disposal, expressed as the Rd and EGP were calculated for the last 30 min of the basal, low- and high-insulin state. (A) Rd and (B–C) difference in Rd compared to basal; (D) EGP suppression (delta EGP %) upon low- and high-insulin infusion. Data are presented as individual data points, mean ± SEM (n = 13). Rd, rate of disappearance; EGP, endogenous glucose production.

Figure 3

Effect of resveratrol (RSV) on ex vivo and in vivo mitochondrial function. After 30 days of resveratrol and placebo, a muscle biopsy specimen was obtained from the vastus lateralis muscle. Part of the specimen was used for evaluation of ex vivo mitochondrial function (n = 10). A: ADP stimulated respiration (state 3) upon a lipid-like substrate and upon parallel electron input into complex I and II. B: Maximally uncoupled respiration upon FCCP (carbonyl cyanide p-(trifluoro-methoxy)-phenylhydrazone). C: the protein content of the individual complexes of the electron transport chain is quantified by western blotting in vastus lateralis muscle. An antibody cocktail that detects all five complexes was used (n = 10). D: in vivo mitochondrial function expressed as PCr half-time (n = 9). Data are presented as individual data points, means ± SEM. *P < 0.05 compared to placebo. M, malate; O, octanoyl-carnitine; G, glutamate; S, succinate; ww, wet weight; OXPHOS, oxidative phosphorylation; PCr, phosphocreatine recovery.

Figure 4

Effect of resveratrol (RSV) on ectopic lipid storage. A: Intrahepatic lipid content quantified by 1H-MRS after 29 days of resveratrol and placebo supplementation. Box plot represents minimum, first quartile, median, third quartile, and maximum (n = 10). B: Muscle biopsy sections for the vastus lateralis muscle were stained for intramyocellular lipid content by Oil Red O staining. Intramyocellular lipid content is quantified as the percentage area of a muscle fiber that is covered by lipids. Data are presented as individuals data points, means ± SEM (n = 9).

Figure 5

Effects of resveratrol (RSV) on in vivo and in vitro brown adipose tissue. A–B: 18F-FDG uptake in BAT, WAT, muscle, and liver after 34 days of placebo and resveratrol intervention (n = 8). BAT SUV max (A) and BAT, SM, WATsc, and liver SUV mean (B–E) were measured under cold-stimulated conditions. (F–G) Respiration was measured in oligomycin (OG)-treated brown (n = 4) and white adipocytes (n = 6) following 1 μM norepinephrine. Data are presented as individual data points, mean ± SEM. BAT, brown adipose tissue; WAT, white adipose tissue; SM, skeletal muscle; SUV, standard uptake value; OCR, oxygen consumption rate.