Liposomal docosahexaenoic acid halts atherosclerosis progression

Background

Atherosclerosis is the main cause underlying cardiovascular disease (CVD). Docosahexaenoic acid (DHA, 22:6n-3) is a hydrophobic polyunsaturated fatty acid that exerts anti-inflammatory and antioxidant activities. However, the beneficial effects of DHA on CVD have been controversial likely due to variations in bioavailability after oral intake.

Purpose

In this study, we aim to investigate the potential inhibiting properties of liposomal DHA on atherosclerosis progression upon intravenous administration.

Methods

Four weeks old ApoE−/− and LDLr−/− mice were fed on athero-inducing high fat diet for 4 weeks and then randomly divided into two groups. The mice received either control liposomes (control group) or liposomes containing DHA (liposomal DHA treatment group) via intravenous injection, twice a week for 8 weeks while still being fed on high fat diet. At the experiment endpoint, whole aortas were collected for Oil Red O staining to quantify plaque area or for biochemical analysis. Plasma was collected for total cholesterol measurement and lipidomic analysis. Aortic roots were used for histological analysis.

Results

Upon intravenous injection, as shown by IVIS imaging, DHA-containing liposomes accumulated preferentially in the atherosclerotic plaques. Compared to control liposomes, liposomal DHA treatment reduced the atherosclerotic plaque area in both atherosclerosis animal models, with the total plaque area decreased by 35.8% in ApoE−/− mice, (p<0.001) and by 22.4% in LDLr−/− mice (p<0.05). Plaque composition analysis revealed that liposomal DHA treatment increased collagen content and reduced the number of macrophages and neutral lipid within the plaques, resulting in a lower plaque vulnerability index (1.095 for liposomal DHA treated group vs. 1.692 for control group, p<0.05). Among those plaque macrophages, as demonstrated by immunohistology, M2 (anti-inflammatory) macrophages accounted for 4.44% in liposomal DHA treated mice and 2.24% in control liposomes treated mice (p<0.05). In agreement with the histology results, higher mRNA expression levels of anti-inflammatory markers (IL-10, CD206 and CD163) and collagen type 1 were determined in aortic tissue after liposomal DHA treatment. Moreover, liposomal DHA did not change total cholesterol level in the blood but significantly lowered plasma levels of several species of triglycerides. In vitro experiment with bone marrow derived macrophages showed that liposomal DHA was able to suppress lipopolysaccharide-induced inflammatory response and oxidative stress.

Conclusions

Our findings demonstrate that incorporation of DHA in injectable liposomes is an effective way to increase the inhibitory effects of DHA on halting the progression of atherosclerosis via lowering circulating triglycerides, reducing plaque inflammation, and enhancing plaque stability. Intravenous administration of liposomal DHA may become an efficacious strategy for the treatment of atherosclerosis.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): NUSMed Seed Fund

Anisotropic hydrogel fabricated by controlled diffusion as a bio-scaffold for the regeneration of cartilage injury

Controlled fabrication of anisotropic materials has become a hotspot in materials science, particularly biomaterials, since the next generation of tissue engineering is based on the application of heterogeneous structures that can simulate the original biological complexity of the body. The current fabrication method of producing anisotropic materials involves expensive and highly specialized equipment, and not every conventional method can be applied to preparing anisotropic materials for corresponding tissue engineering. Anisotropic materials can be easily applied to a problem in tissue engineering: cartilage injury repairing. The articular cartilage consists of four spatially distinct regions: superficial, transitional, deep, and calcified. Each region has a specific extracellular matrix composition, mechanical properties, and cellular organization; this calls for the application of an anisotropic hydrogel. Controlled diffusion, under the assistance of buoyancy, has been considered a generalized method to prepare materials using a gradient. The diffusion of two solutions can be controlled through the difference in their densities. In addition to providing anisotropy, this method realizes the in situ formation of an anisotropic hydrogel, and simplifies the preparation process, freeing it from the need for expensive equipment such as 3D printing and microfluidics. Herein, an anisotropic hydrogel based on a decellularized extracellular matrix is fabricated and characterized. The as-prepared scaffold possessed specific chemical composition, physical properties, and physiological factor gradient. In vitro experiments ensured its biocompatibility and biological effectiveness; further in vivo experiments confirmed its application in the effective regeneration of cartilage injury.

[Risk factors and predictors of persistent ectopic pregnancy after interstitial pregnancy surgery]

Objective: To explore the related factors and early predictors of persistent ectopic pregnancy (PEP) in patients with interstitial pregnancy after operation. Methods: The clinical data of patients with interstitial pregnancy who underwent surgery in the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital from January 2013 to August 2021 were collected. Patients were divided into two groups according to whether PEP occurred (8 patients in PEP group and 124 patients in non-PEP group). Using propensity score matching (PSM) analysis, the basic data, surgical methods, the ratio of postoperative to preoperative serum β-human chorionic gonadotropin (β-hCG), the duration of when the serum β-hCG had decreased to normal after the operation were compared and analyzed to find the related factors of PEP after interstitial pregnancy surgery. The sensitivity and specificity of the ratio of 24-48 hours postoperative β-hCG to preoperative β-hCG in predicting postoperative PEP were evaluated by drawing receiver operating characteristic (ROC) curve. Results: Before PSM, the ages of patients in PEP group and non-PEP group were (30.0±4.0) and (32.4±5.0) years old, respectively, P>0.05. After PSM, 8 PEP patients in the study group and 29 patients in the control group were matched successfully, and the ages of the two groups were (30.0±4.0) and (30.1±3.2) years old, respectively, P>0.05. After PSM, there was no significant difference in gravidity, parity, menopausal days, preoperative β-hCG level and maximum diameter of lesions, all P>0.05. After PSM, the proportion of patients with maximum diameter ≤ 2.6 cm in PEP group (6/8) was significantly higher than that in control group (31.0%, 9/29), P=0.025. The median (Q₁, Q₃) of the ratio of 24-48 hours postoperative β-hCG to preoperative β-hCG ratio was 52.9% (49.9%, 59.7%) in the PEP group, which was significantly higher than 31.5% (23.8%, 39.0%) in the control group (P=0.001); The median (Q₁, Q₃) of duration of when the serum β-hCG had decreased to normal after the operation in PEP group was 52.0 (34.8, 92.0) d, which was significantly higher than 24.0 (20.5, 31.0) d in control group (P<0.001). The ROC-Area Under Curve of the ratio of 24-48 hours postoperative β-hCG to preoperative β-hCG ratio for predicting postoperative PEP in the two groups was 0.892 (95%CI: 0.725-1.000, P=0.001). The cut-off value for predicting PEP was 48.5%, where the diagnostic sensitivity was 87.5%, the specificity was 93.1%. Conclusions: In the operation of interstitial pregnancy, the maximum diameter of lesion ≤ 2.6 cm is a related factor for postoperative PEP. There was no significant difference in the risk of PEP between cornuotomy and cornectomy. The ratio that 24-48 hours postoperative β-hCG/preoperative β-hCG ratio greater than 48.5% was a reference index for predicting postoperative PEP and guiding treatment.

[A prospective cohort study on refractive status of schoolchildren in Huangzhong District, Xining City, Qinghai Province]

Objective: To determine the characteristics and progress of the visual acuity and refractive state of schoolchildren in Huangzhong District, Xining City, Qinghai Province in China. Methods: Cohort study. Department of Ophthalmology, Beijing Children's Hospital carried out a cohort study by collecting the visual acuity and refractive state of Grade 1-5 schoolchildren among 16 primary schools in Huangzhong District, Xining City, Qinghai Province in September 2020 and July 2021. Cycloplegic retinoscopy with eye drop which contained tropicamide (0.5%) and phenylephrine hydrochloride (0.5%) was performed in children with low vision(<1.0). Myopia was defined as the spherical equivalent (SE) ≤-0.5 D after cycloplegic retinoscopy. Measurement data was analyzed by t-test and enumeration data was analyzed by χ² test. Multiple linear regression was used to analyze the influencing factors. Results: The 2 489 individuals with repeated tests in two years were included in the follow-up study, among whom the prevalence of myopia was 26.24%(653/2 489) in 2020, while 32.94% (820/2 489)respectively in 2021. The incidence of myopia in one school year from grades 1 to 5 was 11.19%(47/420), 5.44%(21/386), 6.39%(25/391), 11.52%(44/382) and 11.67%(30/257). The average SE of children in all grades in 2021 increased negatively from the previous year (Grade 1 to Grade 5 increased respectively: 0.40 D, 0.69 D, 0.62 D, 0.52 D and 0.37 D). Conclusions: The prevalence of myopia among schoolchildren in Huangzhong District, Xining City, Qinghai Province was relatively high. There were two peaks of myopia incidence in the first, fourth and fifth grades. Female, age, and the baseline of SE were the related influencing factors for myopia progression.

Analysis of synthetic electron cyclotron emission from the high field side of HL-2M tokamak plasmas

A synthetic electron cyclotron emission (ECE) diagnostic is used to interpret ECE signals from preset plasma equilibrium profiles, including magnetic field, electron density, and electron temperature. According to the simulation results, the electron temperature (T_e) profile covering the harmonic overlap region can be obtained by receiving ECE signals at the high field side (HFS) of the HL-2M plasma. The third harmonic ECE at the low field side (LFS) cannot pass through the second harmonic resonance layer at the HFS unless the optical thickness (τ) of the second harmonic becomes gray (τ ≤ 2). In addition, the impact of the relativistic frequency down-shift has been evaluated and corrected. The measurable range of the HFS ECE has been calculated by scanning different parameters (electron density, temperature, and magnetic field). Higher plasma parameters allow a wider radial range of electron temperature measurements. The minimum inner measurable position can reach R = 120 cm (r/a = -0.89) when the product of core temperature (T_e0) and density (n_e0) is greater than 35 × 10¹⁹ keV m^-3, which is extended by more than 30 cm inward compared with that of the LFS measurement. The HFS ECE will greatly improve the diagnostic ability of ECE systems on the HL-2M tokamak.

Prefrontal projections to the nucleus reuniens signal behavioral relevance of stimuli during associative learning

The nucleus reuniens (RE) is necessary for memories dependent on the interaction between the medial prefrontal cortex (mPFC) and hippocampus (HPC). One example is trace eyeblink conditioning, in which the mPFC exhibits differential activity to neutral conditioned stimuli (CS) depending on their contingency with an aversive unconditioned stimulus (US). To test if this relevancy signal is routed to the RE, we photometrically recorded mPFC axon terminals within the RE and tracked their changes with learning. As a comparison, we measured prefrontal terminal activity in the mediodorsal thalamus (MD), which lacks connectivity with the HPC. In naïve male rats, prefrontal terminals within the RE were not strongly activated by tone or light. As the rats associated one of the stimuli (CS+) with the US, terminals gradually increased their response to the CS+ but not the other stimulus (CS-). In contrast, stimulus-evoked responses of prefrontal terminals within the MD were strong even before conditioning. They also became augmented only to the CS+ in the first conditioning session; however, the degree of activity differentiation did not improve with learning. These findings suggest that associative learning selectively increased mPFC output to the RE, signaling the behavioral relevance of sensory stimuli.

O-057 The pregnant outcome after laparoscopy treatment for subtle distal fallopian tube abnormalities in infertile population: a prospective cohort study

Study question

What is the the pregnancy outcome after laparoscopy treatment for subtle distal fallopian tube abnormalities and the factors related with natural pregnancy.

Summary answer

The natural pregnancy rate is 46.58% after laparoscopy and patients' age, duration time of infertility and concurrent number of abnormalities are related with natural pregnancy.

What is known already

Subtle distal fallopian tube abnormalities are a group of diseases that are characterized by subtle variations in tubal anatomy including fimbrial agglutination, tubal diverticula, accessory ostium, fimbrial phimosis, and accessory fallopian tube. The prevalence of subtle distal fallopian tube abnormalities is high in infertile women.This group of diseases is highly related to endometriosis, especially its early stage, and may indicate fimbrial abnormalities in endometriosis.

Study design, size, duration

This was a prospective cohort study conducted in the Reproductive Medicine Center of an university-affiliated teaching hospital from January 2017 to December 2018.

Participants/materials, setting, methods

234 patients with subtle distal fallopian tube abnormalities were included. Laparoscopies were performed by four senior reproductive surgeons who were familiar with the diagnostic criteria and surgery treatment for subtle abnormalities. The fallopian tube abnormalities were corrected and endometriosis was treated by either electrical ablation for peritoneal lesions or endometrioma excision.The participants were followed up by phone every 12 months for pregnancy outcome until 36 months after surgery.

Main results and the role of chance

167 patients conceived after surgery(clinical pregnancy rate 71.37%). 109 patients conceived naturally (natural pregnancy rate 46.58%) and 59 patients conceived after in IVF（One case conceived naturally after live birth after IVF, four cases conceived naturally twice) . The average time for natural conception after surgery is 8.36±7.47 months. 51.4% of natural pregnancy occurred within 6 months and 79.8% occurred within 12 months.Among the 109 naturally conceived patients, there were 94 cases of live birth, 13 cases of natural abortion (natural abortion rate 11.92%) and 2 cases of ectopic pregnancy (ectopic pregnancy rate 1.83%). No preterm birth, multiple pregnancy or birth defects were reported in this group.The patient age(HR = 0.917,95%CI 0.870-0.917,P=0.001), duration of infertility(HR = 0.846,95%CI 0.740-0.966,P=0.014) and concurrent number of subtle abnormalities (HR = 0.636,95%CI 0.416-0.970,P=0.036) are the factors associated with natural pregnancy. The type of subtle abnormalities, type of infertility, body mess index, concurrent endometriosis, uterine cavity abnormalities and myoma are not related with natural pregnancy.

Limitations, reasons for caution

Not all kinds of subtle distal abnormalities are included such as paratubal cyst is excluded from the study. Not all the patients had the test of ovarian reserve such as AMH, antral follicle count and FSH level, so we couldn’t evaluate the relationship between ovarian reserve and natural pregnancy.

Wider implications of the findings

This is the largest clinical study that investigated the pregnancy outcome of subtle fallopian tube abnormalities in the infertile population.Laparoscopy surgery is an effective treatment for infertility patients with subtle distal fallopian tube abnormalities, especially for the young, short duration time of infertility and ≤2 types of subtle abnormalities.

Trial registration number

ChiCTR2000029095

POS0218 DECREASED miR-122-5p IN NEUTROPHIL-DERIVED EXOSOMES ATTENUATED IMMUNOREGULATORY FUNCTION ON MACROPHAGES BY TARGETING IRF5 EXPRESSION IN BEHCET’S DISEASE

Background

Behçet’s disease (BD) is a chronic systemic vasculitis characterized by the overactivation of neutrophils and macrophages. Exosomes are membrane-derived vesicles that mediate intercellular communications and neutrophil-derived exosomes account for the major portion of serum exosomes in BD. However, the role of neutrophil-derived exosomes in BD remains unknown.

Objectives

1) To investigate the production of exosomes by BD neutrophils; 2) To elucidate the regulation of macrophage by BD neutrophil-derived exosomes; 3) To explore the mechanism of immunoregulatory functions of BD neutrophil-derived exosomes.

Methods

BD and healthy control (HC) neutrophil-derived exosomes were extracted and quantified. Human monocyte-derived macrophages (HMDM) were stimulated with BD and HC neutrophil-derived exosomes, and TNF-α and IL-6 production were examined. Differently expressed miRNAs in BD neutrophil-derived exosomes were analyzed using miRNA sequencing. LPS-induced HMDM were treated with miRNA mimics or inhibitors, and TNF-α and IL-6 production were detected. miRNA was overexpressed in macrophages, and RNA sequencing was performed to analyze regulating pathways. Dual-luciferase assays were performed to confirm miRNA-mRNA interaction.

Results

BD neutrophils produced a significantly lower level of exosomes than HC ones. Both BD and HC neutrophil-derived exosomes suppressed TNF-α and IL-6 production by macrophages, but to a lesser extent by BD neutrophil-derived exosomes. Six downregulated miRNAs were presented in BD neutrophil-derived exosomes, including miR-122-5p. miR-122-5p mimics inhibited IL-6 and TNF-α production while miR-122-5p inhibitor promoted IL-6 and TNF-α production by HMDMs. Overexpression of miR-122-5p attenuated TLR4 and IFN-β signaling. miR-122-5p directly targeted 3’UTR of IRF5, the TF regulating TLR4 pathway and autocrine of IFN-β, and downregulated IRF5 expression confirmed by dual luciferase assay. Knocking down IRF5 dampened IL-6 and TNF-α production in HMDMs.

Figure 1.

(A) Decreased production of BD neutrophil-derived exosomes. (B) Reduced suppression of macrophage activation by BD neutrophil-derived exosomes. (C) Differentially expressed miRNAs (downregulated) in BD neutrophil-derived exosomes. (D) miR-122-5p suppressed TLR4 and JAK-STAT signaling in HMDM. (E) miR-122-5p inhibited activation of HMDM. (F) miR-122-5p inhibited IRF5 expression in HMDM.

Conclusion

Our findings suggested the reduced production and immunoregulatory function of BD neutrophil-derived exosomes, mediated by lower levels of miR-122-5p in neutrophil-derived exosomes. Impaired BD neutrophil-derived exosomes might be implicated in the overactivation of macrophages in BD.

References

[1]Kolonics, Ferenc et al. Cells vol. 9,12 2718. 18 Dec. 2020,

Disclosure of Interests

None declared

POS0471 INDUCED ANTIBODIES DIRECTED TO THE ANGIOTENSIN RECEPTOR TYPE 1 PROVOKE SKIN AND LUNG INFLAMMATION AND DERMAL FIBROSIS AND ACT SPECIES OVERARCHING

Background

Antibodies directed to the angiotensin receptor type 1 (AT1R) were found to be increased in patients with SSc ad they predict mortality and SSc complications (1, 2). In vitro studies suggested an involvement in the pathogenesis of systemic sclerosis (SSc).

Objectives

Here, we aim to determine the contribution and functions of AT1R autoantibodies (Abs) in vivo and in vitro as well as their capacity to recognize AT1R from different species.

Methods

C57BL/6J mice were immunized with membrane-embedded human AT1R or empty membrane as control. Phenotypic properties of various organs were examined by immunohistochemistry, immunofluorescence, and TUNEL apoptosis assay. A monoclonal (m)AT1R Ab was generated based upon this mouse model by hybridoma technology and transferred into C57BL/6J mice. Mice deficient for CD4+ and CD8+ T cells, B cells and AT1Ra/b served as controls. In vitro, Abs responses towards AT1R were measured using rat cardiomyocytes, human epithelial cells, AT1R-transfected HEK293 cells and primary human monocytes.

Results

AT1R-immunized mice developed perivascular skin and lung inflammation, lymphocytic alveolitis, weak endothelial apoptosis and skin fibrosis, not present in controls or mice deficient for CD4+ T and B cells. The contribution of AT1R Abs to skin manifestations and interstitial lung disease was demonstrated by application of a mAT1R Ab, which induced skin and lung inflammation, not observed in the AT1Ra/b knockout mice. IgG from immunized mice containing AT1R Abs and/or the mAT1R Ab activated rat cardiomyocytes and human monocytes. Treatment of AT1R-transfected HEK293 cells with the mAT1R Ab enhanced AT1R signaling in the presence of the endogenous agonist Angiotensin II.

Conclusion

Our immunization strategy successfully induced AT1R Abs, contributing to inflammation and most likely to fibrosis via activation of AT1R. Therefore, AT1R Abs are valuable targets for future therapies in SSc and possibly other AT1R Ab-related diseases.

References

[1]Riemekasten, G. et al. Involvement of functional autoantibodies against vascular receptors in systemic sclerosis. Ann. Rheum. Dis. 70, 530–536 (2011).

[2]Becker, M. O. et al. Vascular receptor autoantibodies in pulmonary arterial hypertension associated with systemic sclerosis. Am. J. Respir. Crit. Care Med. 190, 808–817 (2014).

Figure 1.

AT1R immunization and induction of AT1R Abs in C57BL/6J mice induced lymphocytic alveolitis in bronchoalveolar fluid (A), interstitial lung disease (B) with increased inflammatory score (C)

Figure 2.

AT1R immunization and induction of AT1R Abs in C57BL/6J mice induced skin fibroses (A) as determined by collagen content (B) and skin thickness (C).

Acknowledgements

This manuscript was founded by the German Research Council RI1056/11-1-3 and the Excellence Cluster Precision Medicine in Inflammation and by the BMBF-founded Mesinflame project.

Disclosure of Interests

None declared.

Outcome-Locked Cholinergic Signaling Suppresses Prefrontal Encoding of Stimulus Associations

Acetylcholine (ACh) is thought to control arousal, attention, and learning by slowly modulating cortical excitability and plasticity. Recent studies, however, discovered that cholinergic neurons emit precisely timed signals about the aversive outcome at millisecond precision. To investigate the functional relevance of such phasic cholinergic signaling, we manipulated and monitored cholinergic terminals in the mPFC while male mice associated a neutral conditioned stimulus (CS) with mildly aversive eyelid shock (US) over a short temporal gap. Optogenetic inhibition of cholinergic terminals during the US promoted the formation of the CS-US association. On the contrary, optogenetic excitation of cholinergic terminals during the US blocked the association formation. The bidirectional behavioral effects paralleled the corresponding change in the expression of an activity-regulated gene, c-Fos in the mPFC. In contrast, optogenetic inhibition of cholinergic terminals during the CS impaired associative learning, whereas their excitation had marginal effects. In parallel, photometric recording from cholinergic terminals in the mPFC revealed strong innate phasic responses to the US. With subsequent CS-US pairings, cholinergic terminals weakened the responses to the US while developing strong responses to the CS. The across-session changes in the CS- and US-evoked terminal responses were correlated with associative memory strength. These findings suggest that phasic cholinergic signaling in the mPFC exerts opposite effects on aversive associative learning depending on whether it is emitted by the outcome or the cue.SIGNIFICANCE STATEMENT Drugs compensating for the decline of acetylcholine (ACh) are used for cognitive impairment, such as Alzheimer's disease. However, their beneficial effects are limited, demanding new strategies based on better understandings of how ACh modulates cognition. Here, we report that by manipulating ACh signals in the mPFC, we can control the strength of aversive associative learning in mice. Specifically, the suppression of ACh signals during an aversive outcome facilitated its association with a preceding cue. In contrast, the suppression of ACh signals during the cue impaired learning. Considering that this paradigm depends on the brain regions affected in Alzheimer's disease, our findings indicate that precisely timed control of ACh signals is essential to refine ACh-based strategies for cognitive enhancement.

[Equol and its enantiomers inhibited urethane-induced lung cancer in mice]

OBJECTIVE

To investigate the effects and mechanisms of equol and its enantiomers on urethane-induced lung cancer in mice.

METHODS

A total of 120 5-week-old male C57BL/6 mice were randomly divided into 8 groups: lung cancer tumor control group (CG), genistein control group (GCG), low dose racemic equol group (LEG), high dose racemic equol group (HEG), low dose R-equol group (LRE), high dose R-equol group (HRE), low dose S-equol group (LSE) and high dose S-equol group (HSE). Urethane was injected subcutaneously twice a week for 4 weeks to induce lung cancer and then the mice were fed for 4 months. The body weight and food intake of each group were measured and recorded weekly. After the mice were sacrificed, the blood, livers and lungs of the mice were collected. The incidence of lung cancer in each group was recorded. The concentration of serum superoxide dismutase (SOD), malondialdehyde (MDA) and 8-hydroxydeoxygunosine (8-OHdG) were detected by the corresponding kits. Western blotting was used to detect the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in the livers. Between-group differences in body weight and food intake of the mice were compared using repeated measures ANOVA, and ANOVA for the differences between non-repeated measurements, with post hoc analysis using Tukey's method if there were between-group differences. Comparisons of categorical data were performed by chi-square test, and if there were differences between the groups, the Bonferroni method was used for pairwise comparison.

RESULTS

A total of 49 in the 120 mice developed lung cancer. The overall incidence of lung cancer was 40.8%. Compared with the control group, the incidence of lung cancers in each experimental group was lower, and the difference was statistically significant. The incidence of lung cancer in the high-dose experimental group was significantly lower than that in the low-dose experimental group. However, the incidence of lung cancer was similar in the three equol groups and the genistein group at the same dose. Compared with the control group, the high-dose experimental group had higher serum SOD concentration, lower MDA and 8-OHdG concentrations, and the differences were statistically significant. Western blotting analysis showed that the expression levels of Nrf2 protein in the experimental groups were higher than those in the control group except the low-dose racemic equol group, and the Nrf2 protein expression level in the high-dose equol groups was higher than that in the low-dose equol groups.

CONCLUSION

Racemic equol and its enantiomers mayinhibit lung carcinogenesis through antioxidant effects.