In vivo and in vitro evidences that carotenoids could modulate the neutrophil respiratory burst during dietary manipulation.
BACKGROUND
The primary role of polymorphonuclear neutrophils (PMNs) is to destroy pathogenic microorganisms after phagocytosis by producing reactive oxygen species (ROS) and toxic molecules. However, PMNs produce sufficient amounts of ROS during an oxidative burst to be autotoxic and detrimental to their own functions and to possibly cause DNA damage, protein and lipid oxidation and cell membrane destructuration.


OBJECTIVE
The aim of this study was to investigate in vivo the role of the antioxidant capacities of carotenoids in modulating ROS content in PMNs during oxidative burst. Moreover to investigate the direct or indirect effect of carotenoids, the modification of PMN ROS content was explored after in vitro supplementation with beta-carotene or lycopene, chosen taking account of their vitamin A and no vitamin A precursor effect, respectively.


METHODS
In vivo study: Venous blood was collected from 10 healthy male volunteers and ROS production from phorbol myristate acetate (PMA)-stimulated PMNs was determined, by flow cytometry using the fluorescent dye dihydrorhodamine 123, at baseline, after 3 weeks of carotenoid depletion (carotenoid intake limited to 25% of usual intake) and after 5 weeks of carotenoid repletion (30 mg beta-carotene, 15 mg lycopene and 9 mg lutein per day). In vitro study: ROS content in PMA-stimulated PMNs isolated from carotenoid depleted subjects and controls was quantified after an in vitro enrichment with beta-carotene (1 micromol/L) or lycopene (0.3 micromol/L).


RESULTS
In vivo carotenoid depletion increased PMN H2O2 content after PMA activation by 38% (p < 0.05 vs baseline),while supplementation for 5 weeks restored basal H2O2 generation (p < 0.05 vs depletion). Although H2O2 measurement in PMNs from non-depleted subjects was not affected by an in vitro supply with beta-carotene or lycopene, a significant decrease in H2O2 content by 78.9 % and 81.2%, respectively, was observed in PMNs from carotenoid depleted subjects (p < 0.01 vs depleted control subjects).


CONCLUSIONS
The carotenoid ROS quenching capacities control both in vivo and in vitro the PMNs ROS generation and probably protect these cells against DNA, membrane lipid and protein damages during oxidative burst. Moreover, these effects appear independent from the metabolic conversion of carotenoids to vitamin A.
Laboratoire de Biochimie, Biologie Moléculaire et Nutrition, EA 2416, Faculté de Pharmacie Centre de Recherche en Nutrition Humaine d'Auvergne, 28 place Henri-Dunant, BP 38, 63001, Clermont-Ferrand cedex, France.
Stéphane
S
Walrand
Marie-Chantal
MC
Farges
Olivier
O
Dehaese
Nicolas
N
Cardinault
Régine
R
Minet-Quinard
Pascal
P
Grolier
Corinne
C
Bouteloup-Demange
Josep
J
Ribalta
Brigitte M
BM
Winklhofer-Roob
Edmond
E
Rock
Marie-Paule
MP
Vasson
D000975:Antioxidants / Q000494:pharmacology / Q000502:physiology*; D002338:Carotenoids / Q000097:blood / Q000494:pharmacology* / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism; D066298:In Vitro Techniques; D000077276:Lycopene; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology; D019207:beta Carotene / Q000494:pharmacology / Q000502:physiology
D000975:Antioxidants; D017382:Reactive Oxygen Species; D019207:beta Carotene; D002338:Carotenoids; D006861:Hydrogen Peroxide; D000077276:Lycopene