Linoleic Acid Production Research Articles

Characterization of Linum usitatissimum L. used in Tunisia as food crop

This paper deals with the analysis of seed and seed oil of Linum usitatissimum of Tunisian origin in terms of physicochemical properties, fatty acid, sterol and triacylglycerol compositions, thermal characteristics UV/Vis, DSC profile, IR and NMR spectroscopic analysis. Some of these properties were compared to those of linseed and linseed oil from other countries. The contents of moisture, ash, protein, and carbohydrates in the seeds were 3.60, 3.17, 14 and 48.16%, respectively. The physicochemical properties of LOT included: acid value (0.9 mg KOH/g of oil), iodine value (142.12 g/100 g of oil), peroxide value (3.5 meqO2/kg) and saponification number (200.5). Linolenic acid (58.59%), oleic acid (16.67%), linoleic acid (15.50%) and palmitic acid (5.44%) were the major fatty acids in LOT. The dominant polyunsaturated triacylglycerols found in LOT are LnLnLn, LnLLn, LnOLn, LnLnP (Ln: Linolenic; L: Linoleic; O: Oleic and P: Palmitic acids). The main sterol found in LOT was β-sitosterol (51.31%). The DSC melting curve reveals that the melting point of LOT is −32.96 °C and the melting enthalpy is 22.79 J/g. This study has shown that L. usitatissimum seed and seed oil from Tunisia is useful in different fields such as nutrition, cosmetic by its richness in linoleic acid (ω-3) and paint products due to its rapid drying as well as pharmaceutical area.

Simultaneous determination of Ltx and Ltxd in cured meat products by LC/MS/MS

9,10-Epoxyoctadec-12-enoic acid (Ltx) and 9,10-dihydroxy-12-octadecenoic acid (Ltxd), oxidation products of Linoleic acid, are of biological significance. In this paper, a method was developed for simultaneous determination of Ltx and Ltxd in cured meat products. The analytes were separated by high performance liquid chromatography and detected with tandem mass spectrometry. The method was of satisfactory performances with the quantification limits of 0.64μg/g and 0.025μg/g for Ltx and Ltxd, respectively. The method was employed to detect the analytes in cured meat products, and 21 out 26 samples were found to contain Ltx and Ltxd simultaneously, in ranges of 0.77-6.90μg/g and 0.17-3.93μg/g, respectively. The result also indicated there were isomers of Ltx and Ltxd in samples, and the final amount of Ltxds after ingestion might be much higher than those originally detected in cured meats. More attention should be paid to Ltxs and Ltxds in cured meat products.

Linoleic acid-derived lipid mediators increase in a female-dominated subphenotype of COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality; however, the role of inflammatory mediators in its pathobiology remains unclear. The aim of this study was to investigate the influence of gender in COPD on lipid mediator levels.Bronchoalveolar lavage fluid (BALF) and serum were obtained from healthy never-smokers, smokers and COPD patients (Global Initiative for Chronic Obstructive Lung Disease stage I-II/A-B) (n=114). 94 lipid mediators derived from the cytochrome-P450, lipoxygenase, and cyclooxygenase pathways were analysed by liquid chromatography-mass spectrometry.Multivariate modelling identified a 9-lipid panel in BALF that classified female smokers with COPD from healthy female smokers (p=6×10(-6)). No differences were observed for the corresponding male population (p=1.0). These findings were replicated in an independent cohort with 92% accuracy (p=0.005). The strongest drivers were the cytochrome P450-derived epoxide products of linoleic acid (leukotoxins) and their corresponding soluble epoxide hydrolase (sEH)-derived products (leukotoxin-diols). These species correlated with lung function (r=0.87; p=0.0009) and mRNA levels of enzymes putatively involved in their biosynthesis (r=0.96; p=0.003). Leukotoxin levels correlated with goblet cell abundance (r=0.72; p=0.028).These findings suggest a mechanism by which goblet cell-associated cytochrome-P450 and sEH activity produce elevated leukotoxin-diol levels, which play a putative role in the clinical manifestations of COPD in a female-dominated disease sub-phenotype.

Identification of two genes encoding microsomal oleate desaturases (FAD2) from the biodiesel plant Pongamia pinnata L.

The current study dissect microsomal oleate desaturase genes having differential expression pattern with respect to temperature from the seeds of Pongamia pinnata, and are grouped with other legumes and biofuel plants. Biofuel often is available as plant oil or products derived thereafter, such as biodiesel. In view of the anticipated fossil fuel shortage, the biochemical and genetic basis of vegetable oil biosynthesis is vital. We are focusing on the versatile oil-yielding legume tree Pongamia pinnata. Microsomal oleate desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in non-photosynthetic tissues. This work reports on the isolation of two full length cDNA clones, tissue expression and copy number detection of Pongamia FAD2 genes, and also on the transcriptional regulation at low and high temperatures. The deduced amino acid sequences of both PpFAD2 proteins share 83 % identity and display three typical histidine boxes that are characteristics of all membrane-bound microsomal oleate desaturases. Both sequences possess aromatic amino acid containing sequence motifs at the C-terminal end necessary for maintaining endoplasmic reticulum (ER) localization. Southern blot analysis is consistent with the presence of at least two copies of FAD2 in the pongamia genome. Quantitative real-time PCR analysis showed that PpFAD2-1 is expressed strongly in developing seeds and, showing very low levels of expression in vegetative tissues, whereas PpFAD2-2 is constitutively expressed in both vegetative tissues and the developing seeds, with higher transcript levels in roots, stems and leaves. In response to low temperature stress PpFAD2-1 and PpFAD2-2 were differentially expressed in various tissues. The PpFAD2-2 transcript dramatically decreased in roots, stems and leaves under low temperatures, whereas PpFAD2-1 showed a significant increase in these tissues.

Characterization of Conjugated Linoleic Acid-Producing Lactic Acid Bacteria as Potential Probiotic for Chicken

Aims: Dietary intake of conjugated linoleic acid (CLA) by human is insufficient to exhibit properties of anti-cancer, anti-inflammatory, anti-atherosclerosis, anti-obesity and enhancing immune system. Thus, enrichment of CLA in chicken by bacteria is a suggestion to solve the problem. It would be an advantage to have bacteria capable of producing CLA and has probiotic potential in chicken. Thus, probiotic properties of CLA-producing bacteria were accessed in this study. Methodology and results: In this study, 47 lactic acid bacteria (LAB) isolated from gastrointestinal tract of chickens were screened for conjugated linoleic acid (CLA) production. Lactobacillus salivarius strain P2, Enterococcus faecium strain P1 and Lactobacillus agilis strain P3 were shown to produce 21.97, 23.35 and 31.08 μg/mL of CLA in MRS broth containing free linoleic acid (0.5 mg/mL) and 2% (w/v) Tween 80, respectively. Lactobacillus salivarius strain P2, E. faecium strain P1 and L. agilis strain P3 were found to be able to tolerate 0.3% oxgall (Difco, France) and pH 2.5. Lactobacillus agilis strain P3 and L. salivarius strain P2 showed better acid tolerance compared to E. faecium strain P1. Besides that, L. agilis strain P3 and L. salivarius strain P2 were resistant to two out of eight types of antibiotics tested, able to produce 220.04 mM lactic acid and 200.17 mM of lactic acid, respectively. Enterococcus faecium strain P1 was resistant to five out of eight types of antibiotic tested, produced 90.39 mM lactic acid and showed hemolytic activity. Only L. agilis strain P3 can produce acetic acid at a concentration of 2.71 mM. Conclusion, significance and impact of study: These results showed that the CLA-producing L. salivarius strain P2 and L. agilis strain P3 could be potential probiotic bacteria for chickens, which may eventually lead to production of chicken with better meat quality.

Biosynthesis of fatty acids-derived volatiles in ‘Hass’ avocado is modulated by ethylene and storage conditions during ripening

Abstract The aroma in avocados (Persea americana Mill. cv. ‘Hass’) is mainly defined by fatty acids-derived volatile compounds that change according to the fruit maturity stage which is modulated by ethylene. In order to understand the changes in fatty acid substrates and gene expression involved in the synthesis of the key aroma-volatile compounds in avocado after harvest, we performed two trials using avocados harvested with 11% oil content. In the first trial avocados were ripened immediately after harvest at 20 °C until reaching the ready-to-eat stage, and in the second trial, fruit were stored at 5 °C for 30 days and then ripened at 20 °C. In addition, to assess the ethylene effect in the volatile compounds and transcript levels measured, a 100 μl L−1 ethylene application was carried out, at harvest or after storage for trial 1 and 2, respectively. The concentration of the key volatile compounds and fatty acids were performed by gas chromatography, and the changes in the expression of genes related to lipoxygenase derived compounds were measured by q-PCR. The results obtained indicated that ethylene modulated the production of linolenic acid and hexanal, whereas at the gene expression level, only PamLOX transcript changes responded to ethylene application, although its changes were maturity/ripening dependent. The cold storage did not generate significant changes in fatty acids and gene expression levels, but a decreased in the concentration of hexanal during the ripening was observed.

Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass

We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70.

Relationship between Sowing Time, Variety, and Quality in Safflower

This research was carried out to determine the rates of protein and oil production and fatty acid composition and their correlation coefficients in four safflower cultivars (Remzibey, Dincer, Balci, and Yenice) sown in the autumn and spring from 2013 to 2015. The experiment was carried out using split plots in a randomized block design and was replicated 3 times. The study found protein production rates between 15.20 and 18.08%, oil production rates between 24.58 and 31.99%, palmitic acid production rates between 5.93 and 7.01%, stearic acid production rates between 2.13 and 2.53%, oleic acid production rates between 12.08 and 31.58%, linoleic acid production rates between 78.61 and 59.08%, and linolenic acid production rates between 0.11 and 0.15%. Higher seed oil content values were obtained from spring sowing compared to autumn sowing (27.42% and 26.10%), and, in terms of both the evaluated sowing times and cultivars, the highest oil production rates were found in the Balci cultivar (32.20% and 31.78%) for both sowing times. It was determined that there is a positive and significant (r=0.476⁎⁎) relationship between oil with protein production rates but a negative and significant relationship between oil and linolenic acid production rates (r=-0.728⁎⁎). The oleic acid production rate was strongly negatively and significantly correlated with the linoleic acid production rate (r=-0.997⁎⁎).

Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition.

Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31 Bifidobacterium species were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged to B. breve and B. pseudocatenulatum. GC-MS revealed that CLA producer strains yielded 9cis,11trans-CLA and 9trans,11trans-CLA, without any production of other isomers. Hydroxylated forms of LA were absent in producer strains, suggesting that the myosin-cross-reactive antigen (MCRA) protein that exerts hydratase activity is not involved in LA isomerization. Moreover, both CLA producer and nonproducer species bear a MCRA homologue. The strain B. breve WC 0421 was the best CLA producer, converting LA into 68.8% 9cis,11trans-CLA and 25.1% 9trans,11trans-CLA. Production occurred mostly during the lag and the exponential phase. For the first time, production and incorporation of CLA in biomass were assessed. B. breve WC 0421 stored CLA in the form of free fatty acids, without changing the composition of the esterified fatty acids, which mainly occurred in the plasmatic membrane.

Effect of Tween 80 on Conjugated Linoleic Acid Production by Lactobacillus Strains in Reconstituted Skim Milk Powder

Effect of Tween 80 on Conjugated Linoleic Acid Production by Lactobacillus Strains in Reconstituted Skim Milk Powder

Metabolic engineering of long chain-polyunsaturated fatty acid biosynthetic pathway in oleaginous fungus for dihomo-gamma linolenic acid production

Microbial lipids are promising alternative sources of long chain-polyunsaturated fatty acids (LC-PUFAs) for food, feed, nutraceutical and pharmaceutical sectors. Dihomo-γ-linolenic acid (C20:3Δ(8,11,14); DGLA) is an important LC-PUFAs with anti-inflammatory and anti-proliferative effects. To generate a DGLA-producing strain, fatty acid reconstitution in Aspergillus oryzae was performed by metabolic engineering through co-expression of codon-optimized Pythium Δ(6)-desaturase and Δ(6)-elongase, which had high conversion rates of substrates to respective products as compared to the native enzymes. The Δ(6)-desaturated and Δ(6)-elongated products, γ-linolenic acid (C18:3Δ(6,9,12); GLA) and DGLA, were accumulated in phospholipids rather than triacylglycerol. Interestingly, the manipulation of lipid quality in the oleaginous fungus did not affect growth and lipid phenotypes. This strategy might expand to development of the oleaginous fungal strain for producing other tailor-made oils with industrial applications.

Complete genome sequence of Lactobacillus plantarum ZS2058, a probiotic strain with high conjugated linoleic acid production ability

Lactobacillus plantarum ZS2058 was isolated from sauerkraut and identified to synthesize the beneficial metabolite conjugated linoleic acid. The genome contains a 319,7363-bp chromosome and three plasmids. The sequence will facilitate identification and characterization of the genetic determinants for its putative biological benefits.

Metabolic engineering of fatty acid biosynthetic pathway in sesame (Sesamum indicum L.): assembling tools to develop nutritionally desirable sesame seed oil

Vegetable oils are an essential component of human diet, in terms of their health beneficial roles. Despite their importance, the fatty acid profile of most commonly used edible oil seed crop plants are imbalanced; this skewed ratio of fatty acids in the diet has been shown to be a major reason for the occurrence of cardiovascular and autoimmune diseases. Until recently, it was not possible to exert significant control over the fatty acid composition of vegetable oils derived from different plants. However, the advent of metabolic engineering, knowledge of the genetic networks and regulatory hierarchies in plants have offered novel opportunities to tailor-made the composition of vegetable oils for their optimization in regard to food functionality and dietary requirements. Sesame (Sesamum indicum L.) is one of the ancient oilseed crop in Indian subcontinent but its seed oil is devoid of balanced proportion of ω-6:ω-3 fatty acids. A recent study by our group has shed new lights on metabolic engineering strategies for the purpose of nutritional improvement of sesame seed oil to divert the carbon flux from the production of linoleic acid (C18:2) to α-linolenic acid (C18:3). Apart from that, this review evaluates current understanding of regulation of fatty acid biosynthetic pathways in sesame and attempts to identify the major options of metabolic engineering to produce superior sesame seed oil.

Effect of swine wastewater on Jatropha curcas L. oil acidity

Abstract The experiment included a jatropha plantation area of 900 m 2 , of which 216 m 2 were divided into eighteen plots that received six treatments with different amounts of swine wastewater. Applications were performed in triplicate with intervals of three months. Seed harvest was performed manually during the entire plant production period. Oil was extracted with the use of ethanol as a solvent, which is cheaper, less toxic and less damaging to the environment than other organic solvents such as hexane. Acidity was determined by titration with sodium hydroxide (NaOH), in which there was a reduction inversely proportional to the acid number expressed in mg KOH g −1 of oil with the increase of wastewater applied. This result is extremely important for the energy sector, once that in order to enable the production of biodiesel, the acidity of crude oils is usually reduced by oil refining, which is a costly process. In this study we were able to reduce this cost to zero, besides using swine wastewater, which avoids many environmental problems. Analyses by gas chromatography showed that the treatments with higher amounts of wastewater favored an increase in the production of oleic acid (C18:1) that was proportional to the sum of the decreases in the production of linoleic acid (C18:2) and stearic acid (C18). The reduction in the percentage of linoleic acid can be responsible for reducing acidity, giving oil increased stability to oxidation and therefore fewer amounts of free fatty acids.

Effect of different plant extracts, fatty acid and oils on conjugated linoleic acid (CLA) production by Butyrivibrio fibrisolvens

Present study evaluated the effect of added free fatty acids, dietary oils and plant extracts on conjugated linoleic acid (CLA) production potential of anaerobic Butyrivibrio fibrisolvens bacteria. Different concentration of plant extracts of Solanum nigrum, Rumex dentatus, Boerhaavia diffusa Linn., Amaranthus nlitum Linn., Peristrophe bicalyculata, Phyllanthus sp. Leucas aspera and Cuminum cyminum (0.50, 1.0, 1.5%, 2.0, 4.0, 6.0, 8 and 10 mg/ml of media); pure linoleic and linolenic acid (50, 100, 150, 200, 250 μg/ml of media) and dietary oils (50, 100, 150, 200, 250, 300 μg/ml of media) were used in media. The results revealed that an increase in the concentration of fatty acids suppressed growth of B. fibrisolvens and its cell density reached maximum (1.58 OD; 600 nm) at 18 h of incubation. A gradual rise in CLA production by B. fibrisolvens was observed parallel to increasing concentration of dietary oils from 50 to 250 μg/ml followed with slight decrease at level of 300 μg. Supplementation of sunflower oil resulted in highest increment in CLA production among the treatments. Extracts of different plants at different concentrations showed significant changes in CLA production potential by B. fibrisolvens. Cuminum cyminum with 457% increase in CLA concentration was the most efficient extract. Study established that careful optimization of dietary supplementation results in increased activity of B. fibrisolvens thereby facilitating higher CLA production.

Utilisation of potato processing wastewater for microbial lipids and γ-linolenic acid production by oleaginous fungi.

Microbial lipids are considered as the starting material for production of second-generation biofuels and their polyunsaturated fatty acids are rich sources of neutraceuticals. Exploring cheap feedstock for producing microbial lipids is necessary. The present study examined the potential of microbial lipids and γ-linolenic acid (GLA) production by two oleaginous fungi, Aspergillus flavus I16-3 and Mucor rouxii, with potato processing wastewater as a low-cost or no-cost nutrient source. Biochemistry and physiology of two oleaginous fungi, A. flavus I16-3 and M. rouxii, on lipid accumulation showed the two fungi grew well and efficiently utilised the starch in wastewater. On average (P < 0.05), 2.8 and 3.6 g L(-1) of lipids were produced by A. flavus I16-3 and M. rouxii, respectively, with maximum GLA yields of 60 and 100 mg L(-1) . Addition of nutrients to raw wastewater significantly improved (P < 0.05) the lipid and GLA yields; 3.5 and 4.2 g L(-1) of lipids, and 100 and 140 mg L(-1) of GLA were produced by A. flavus I16-3 and M. rouxii, respectively. In addition, the wastewater was efficiently treated, with soluble chemical oxygen demand, total soluble nitrogen and total soluble phosphorus removals up to 60% and 90%, 100% and 98%, and 92% and 81% by A. flavus I16-3 and M. rouxii, respectively. This study demonstrated an alternative approach to valorise potato processing wastewater to produce microbial lipids and GLA (nutraceuticals).

Chemistry of lipid peroxidation products and their use as biomarkers in early detection of diseases.

We developed a novel method to measure hydroxyoctadecadienoic acid (HODE) levels in biological fluids and tissue samples. This method can be used to measure the oxidation products of linoleic acid. Reduction and saponification enabled us to measure hydroperoxides and hydroxides of both free and esterified forms of linoleic acid as total HODE, which includes the enzymatic and non-enzymatic products 9- and 13-(Z, E)-HODEs; the non-enzymatic free radical-mediated products 9- and 13-(E, E)-HODEs; and the specific non-enzymatic singlet oxygen-mediated products 10- and 12-(Z, E)-HODEs. We have recently reported HODE levels in plasma and erythrocytes from healthy volunteers and patients with several diseases and determined that its levels are much higher in patients with lifestyle-related diseases than in healthy volunteers. Furthermore, 10- and 12-(Z, E)-HODE plasma levels can serve as promising biomarkers for the early detection of diabetes. Thus, HODE is a useful biomarker for the assessment of oxidative status, and its efficiency as a biomarker can be improved by using it in combination with other typical biomarkers. This review article focuses on lipid peroxidation biomarkers, including HODE, and discusses their potential in practical and clinical applications in disease prediction.

Optimization of the Hydrolysis of Safflower Oil for the Production of Linoleic Acid, Used as Flavor Precursor.

Commercial lipases, from porcine pancreas (PPL), Candida rugosa (CRL), and Thermomyces lanuginosus (Lipozyme TL IM), were investigated in terms of their efficiency for the hydrolysis of safflower oil (SO) for the liberation of free linoleic acid (LA), used as a flavor precursor. Although PPL, under the optimized conditions, showed a high degree of hydrolysis (91.6%), its low tolerance towards higher substrate concentrations could limit its use for SO hydrolysis. In comparison to the other investigated lipases, Lipozyme TL IM required higher amount of enzyme and an additional 3 h of reaction time to achieve its maximum degree of SO hydrolysis (90.2%). On the basis of the experimental findings, CRL was selected as the most appropriate biocatalyst, with 84.1% degree of hydrolysis. The chromatographic analyses showed that the CRL-hydrolyzed SO is composed mainly of free LA.

Identification and characterization of wild lactobacilli and pediococci from spontaneously fermented Mountain Cheese

The Traditional Mountain Malga (TMM) cheese is made from raw cow's milk by spontaneously fermentation in small farms called "Malga" located in Trentino region. This study was designed to characterize the lactic acid bacteria (LAB) growing on MRS medium, of TMM-cheese at the end of the ripening. Ninety-five LAB were isolated and genotypically characterized by Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) with two primers, species-specific PCR and partial sequencing of 16S rRNA gene. The 95 LAB clustered in 70 biotypes. Pediococcus pentosaceus and Lactobacillus paracasei were the dominant species. Isolates were tested for their growth properties, carbohydrate metabolism, acidifying ability, proteolytic and lipolytic activities, acetoin production, amino-peptidase (AP) activity, biogenic amines production, bile salts hydrolysis, conjugated linoleic acid and γ-aminobutyric acid production. Lb. paracasei isolates resulted to be well adapted to Malga environment and to show the best AP activity and acetoin production. TMM-cheese related LAB showed also interesting health promoting properties and produced bioactive substances. In particular, one Lb. brevis biotype produced a GABA mean value of 129mg/L that is considered a high concentration. The results confirmed that TMM-cheese resident LAB could be exploited for dairy production.

Hydroxyoctadecadienoic acids regulate apoptosis in human THP-1 cells in a PPARγ-dependent manner.

Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP-1 monocytes and adherent THP-1 cells were compared with other C18 fatty acids, LA and α-linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9-HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9-HODE and 13-HODE (but not LA or ALA) markedly increased caspase-3/7 activity (p < 0.001) in both monocytes and adherent THP-1 cells, with 9-HODE the more potent. In addition, 9-HODE and 13-HODE both increased Annexin-V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1 μM), but the effect of HODEs was replicated with apoptosis-inducer camptothecin (10 μM). Only 9-HODE increased DNA fragmentation. The pro-apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD-CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ-regulated apoptotic effects induced by 9-HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9-HODE and 13-HODE are potent--and specific--regulators of apoptosis in THP-1 cells. Their action is PPARγ-dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis.