Maternal genetics and diet modulate vitamin A homeostasis of the offspring and affect the susceptibility to obesity in adulthood in mice.

Perinatal nutrition exerts a profound influence on adult metabolic health. This study aimed to investigate whether increased maternal vitamin A (VA) supply can lead to beneficial metabolic phenotypes in the offspring. The researchers utilized mice deficient in the intestine-specific homeobox (ISX) transcription factor, which exhibit increased intestinal VA retinoid production from dietary ß-carotene (BC). ISX-deficient dams were fed a VA-sufficient or a BC-enriched diet during the last week of gestation and the whole lactation period. Total retinol levels in milk and weanling livers were 2 to 2.5-fold higher in the offspring of BC-fed dams (BC offspring), indicating increased VA supplies during late gestation and lactation. The corresponding VAS and BC offspring (males and females) were compared at weaning and adulthood after being fed either a standard or high-fat diet (HFD) with regular VA content for 13 weeks from weaning. HFD-induced increases in adiposity metrics, such as fat depot mass and adipocyte diameter, were more pronounced in males than females and were attenuated or suppressed in the BC offspring. Notably, the BC offspring were protected from HFD-induced increases in circulating triacylglycerol levels and hepatic steatosis. These protective effects were associated with reduced food efficiency, enhanced capacity for thermogenesis and mitochondrial oxidative metabolism in adipose tissues, and increased adipocyte hyperplasia rather than hypertrophy in the BC offspring. In conclusion, maternal VA nutrition influenced by genetics may confer metabolic benefits to the offspring, with mild increases in late gestation and lactation protecting against obesity and metabolic dysregulation in adulthood.

ß-Carotene accelerates the resolution of atherosclerosis in mice.

ß-Carotene oxygenase 1 (BCO1) catalyzes the cleavage of ß-carotene to form vitamin A. Besides its role in vision, vitamin A regulates the expression of genes involved in lipid metabolism and immune cell differentiation. BCO1 activity is associated with the reduction of plasma cholesterol in humans and mice, while dietary ß-carotene reduces hepatic lipid secretion and delays atherosclerosis progression in various experimental models. Here we show that ß-carotene also accelerates atherosclerosis resolution in two independent murine models, independently of changes in body weight gain or plasma lipid profile. Experiments in Bco1-/- mice implicate vitamin A production in the effects of ß-carotene on atherosclerosis resolution. To explore the direct implication of dietary ß-carotene on regulatory T cells (Tregs) differentiation, we utilized anti-CD25 monoclonal antibody infusions. Our data show that ß-carotene favors Treg expansion in the plaque, and that the partial inhibition of Tregs mitigates the effect of ß-carotene on atherosclerosis resolution. Our data highlight the potential of ß-carotene and BCO1 activity in the resolution of atherosclerotic cardiovascular disease.

Finasteride delays atherosclerosis progression in mice and is associated with a reduction in plasma cholesterol in men.

Finasteride is commonly prescribed to treat benign prostate hyperplasia and male-pattern baldness in cis men and, more recently, trans individuals. However, the effect of finasteride on cardiovascular disease remains elusive. We evaluated the role of finasteride on atherosclerosis using low-density lipoprotein (LDL) receptor-deficient (Ldlr-/-) mice. Next, we examined the relevance to humans by analyzing the data deposited between 2009 and 2016 in the National Health and Nutrition Examination Survey. We show that finasteride reduces total plasma cholesterol and delays the development of atherosclerosis in Ldlr-/- mice. Finasteride reduced monocytosis, monocyte recruitment to the lesion, macrophage lesion content, and necrotic core area, the latter of which is an indicator of plaque vulnerability in humans. RNA sequencing analysis revealed a downregulation of inflammatory pathways and an upregulation of bile acid metabolism, oxidative phosphorylation, and cholesterol pathways in the liver of mice taking finasteride. Men reporting the use of finasteride showed lower plasma levels of cholesterol and LDL-cholesterol than those not taking the drug. Our data unveil finasteride as a potential treatment to delay cardiovascular disease in people by improving the plasma lipid profile.

ß-carotene accelerates the resolution of atherosclerosis in mice.

ß-carotene oxygenase 1 (BCO1) catalyzes the cleavage of ß-carotene to form vitamin A. Besides its role in vision, vitamin A regulates the expression of genes involved in lipid metabolism and immune cell differentiation. BCO1 activity is associated with the reduction of plasma cholesterol in humans and mice, while dietary ß-carotene reduces hepatic lipid secretion and delays atherosclerosis progression in various experimental models. Here we show that ß-carotene also accelerates atherosclerosis resolution in two independent murine models, independently of changes in body weight gain or plasma lipid profile. Experiments in Bco1-/- mice implicate vitamin A production in the effects of ß-carotene on atherosclerosis resolution. To explore the direct implication of dietary ß-carotene on regulatory T cells (Tregs) differentiation, we utilized anti-CD25 monoclonal antibody infusions. Our data show that ß-carotene favors Treg expansion in the plaque, and that the partial inhibition of Tregs mitigates the effect of ß-carotene on atherosclerosis resolution. Our data highlight the potential of ß-carotene and BCO1 activity in the resolution of atherosclerotic cardiovascular disease.

Change in demand for health-related undergraduate studies in Spain during 2015-2021: a temporal series study.

Introduction: The expansion of higher education is a worldwide phenomenon. To our knowledge, there are no studies analyzing the trends in demands of enrollment in health-related studies in Spain. Therefore, the objective was to analyze the change in demand (the number of requests for enrollment divided by the number of offered places) for undergraduate health-related studies in Spain during the period 2015-2021 as well as compare the change by region in the pre (2015-2019) and pandemic (2020-2021) period. Methods: This is an observational (ecological type) study with temporal series analyses using data from public (non-for-profit) higher education institutions from the Integrated University Information System. For the analysis by region, we calculated the demand of all twelve undergraduate health-related degrees and the percentages of change between both periods using the Wilcoxon test. The Joinpoint Regression program was used to analyze the trends in demand for each degree during the 7-year period. Results: Significant (p < 0.001) increases in demand during the pandemic period were observed in all regions. During the pandemic, medicine, biomedicine, nursing, odontology and pharmacy presented a higher demand in comparison with data collected before the pandemic started. In contrast, this pattern was not confirmed in the following cases: physiotherapy, occupational therapy, podiatry, psychology, social work, human nutrition and dietetics. By regions, Navarra, Asturias, and La Rioja presented the most drastic changes. In regions with the biggest number of universities, such as Catalonia, Andalusia and Madrid, the change observed was smaller.

Bioavailability and provitamin A activity of neurosporaxanthin in mice.

Various species of ascomycete fungi synthesize the carboxylic carotenoid neurosporaxanthin. The unique chemical structure of this xanthophyll reveals that: (1) Its carboxylic end and shorter length increase the polarity of neurosporaxanthin in comparison to other carotenoids, and (2) it contains an unsubstituted ß-ionone ring, conferring the potential to form vitamin A. Previously, neurosporaxanthin production was optimized in Fusarium fujikuroi, which allowed us to characterize its antioxidant properties in in vitro assays. In this study, we assessed the bioavailability of neurosporaxanthin compared to other provitamin A carotenoids in mice and examined whether it can be cleaved by the two carotenoid-cleaving enzymes: ß-carotene-oxygenase 1 (BCO1) and 2 (BCO2). Using Bco1-/-Bco2-/- mice, we report that neurosporaxanthin displays greater bioavailability than ß-carotene and ß-cryptoxanthin, as evidenced by higher accumulation and decreased fecal elimination. Enzymatic assays with purified BCO1 and BCO2, together with feeding studies in wild-type, Bco1-/-, Bco2-/-, and Bco1-/-Bco2-/- mice, revealed that neurosporaxanthin is a substrate for either carotenoid-cleaving enzyme. Wild-type mice fed neurosporaxanthin displayed comparable amounts of vitamin A to those fed ß-carotene. Together, our study unveils neurosporaxanthin as a highly bioavailable fungal carotenoid with provitamin A activity, highlighting its potential as a novel food additive.

Sex-Specific Differences in Lipoprotein Production and Clearance.

Therapeutic approaches to reduce atherogenic lipid and lipoprotein levels remain the most effective and assessable strategies to prevent and treat cardiovascular disease. The discovery of novel research targets linked to pathways associated with cardiovascular disease development has enhanced our ability to decrease disease burden; however, residual cardiovascular disease risks remain. Advancements in genetics and personalized medicine are essential to understand some of the factors driving residual risk. Biological sex is among the most relevant factors affecting plasma lipid and lipoprotein profiles, playing a pivotal role in the development of cardiovascular disease. This minireview summarizes the most recent preclinical and clinical studies covering the effect of sex on plasma lipid and lipoprotein levels. We highlight the recent advances in the mechanisms regulating hepatic lipoprotein production and clearance as potential drivers of disease presentation. We focus on using sex as a biological variable in studying circulating lipid and lipoprotein levels.

Lycopene Accumulation in Transgenic Mice Lacking One or Both Carotenoid Cleaving Enzymes.

BACKGROUND: ß-carotene oxygenase 1 (BCO1) and ß-carotene oxygenase 2 (BCO2) are responsible for the cleavage of carotenoids in mammals. OBJECTIVE: The goals of this study were to (1) establish the relative contribution of each enzyme on lycopene accumulation in mice and (2) examine the role of lycopene on gene expression in the gut of wild type (WT) mice. METHODS: We utilized male and female WT, Bco1-/-, Bco2-/-, and Bco1-/-Bco2-/- double knockout (DKO) mice. We gavaged the mice with either 1 mg of lycopene resuspended in cottonseed oil or vehicle as a control group daily for 2 wk. In a second study, we evaluated the effect of dietary vitamin A on lycopene absorption and intestinal gene expression by RT-PCR. We also quantified lycopene concentration isomer distribution by high performance liquid chromatography. RESULTS: Of the 11 tissues measured, the liver accounted for 94 to 98% of the lycopene content across genotypes. We did not observe sex differences between genotypes, although hepatic lycopene levels in Bco1-/- mice were approximately half in comparison to the other genotypes; Bco1-/- verses Bco2-/- (P < 0.0001), DKO mice (P < 0.001), WT (ns). Analyses of mitochondrial lycopene content revealed a 3- to 5-fold enrichment compared with total hepatic content (P < 0.05) in all genotypes and sexes. In our second study, WT mice fed a vitamin A-deficient diet (VAD) accumulated greater amounts of lycopene in the liver than those fed a vitamin A-sufficient diet (VAS) (P < 0.01). These changes were accompanied by an upregulation of the vitamin A-responsive transcription factor intestine specific homeobox (ISX) in mice fed VAD + lycopene and VAS + lycopene diets compared with VAD control-fed mice (P < 0.05). CONCLUSIONS: Our data suggest that BCO2 is the primary lycopene cleavage enzyme in mice. Lycopene concentration was enriched in the mitochondria of hepatocytes independently of genotype, and lycopene stimulated vitamin A signaling in WT mice.

The impact of the COVID-19 pandemic on enrollment in undergraduate health-related studies in Spain.

The aim of this study was to determine whether the pandemic has reinforced the choice of pursuing health-related bachelor's degrees, and to identify underlying factors that could contribute to that impact. This is a cross-sectional study using an online survey of 2,344 students of nursing, physiotherapy, medicine, psychology and podiatry who started health-related bachelor's degrees after the COVID-19 outbreak in Spanish higher education institutions. The pandemic influenced the choice of these studies by increasing the desire to help others (33.2%), by increasing citizenship values (28.4%), and by increasing the desire to contribute to improving the situation of the country (27.5%). Women had a significantly greater influence on the increase in social values related to the practice of the profession produced by the pandemic, whereas men and the bachelor's degree in podiatry were more influenced by salary prospects. An increased desire to help others was significantly higher among women and nursing and medical students. Podiatry and psychology were the degrees were most influenced by the pandemic, as more students decided to pursue them, something they had previously doubted, while in nursing, psychology, and medicine the pandemic reinforced their interest in pursuing the degree the most. Students personally affected by COVID-19 reported being more influenced in reconsidering their professional path and in reinforcing their desire to pursue the health-related studies.

DIAPH1 mediates progression of atherosclerosis and regulates hepatic lipid metabolism in mice.

Atherosclerosis evolves through dysregulated lipid metabolism interwoven with exaggerated inflammation. Previous work implicating the receptor for advanced glycation end products (RAGE) in atherosclerosis prompted us to explore if Diaphanous 1 (DIAPH1), which binds to the RAGE cytoplasmic domain and is important for RAGE signaling, contributes to these processes. We intercrossed atherosclerosis-prone Ldlr-/- mice with mice devoid of Diaph1 and fed them Western diet for 16 weeks. Compared to male Ldlr-/- mice, male Ldlr-/- Diaph1-/- mice displayed significantly less atherosclerosis, in parallel with lower plasma concentrations of cholesterol and triglycerides. Female Ldlr-/- Diaph1-/- mice displayed significantly less atherosclerosis compared to Ldlr-/- mice and demonstrated lower plasma concentrations of cholesterol, but not plasma triglycerides. Deletion of Diaph1 attenuated expression of genes regulating hepatic lipid metabolism, Acaca, Acacb, Gpat2, Lpin1, Lpin2 and Fasn, without effect on mRNA expression of upstream transcription factors Srebf1, Srebf2 or Mxlipl in male mice. We traced DIAPH1-dependent mechanisms to nuclear translocation of SREBP1 in a manner independent of carbohydrate- or insulin-regulated cues but, at least in part, through the actin cytoskeleton. This work unveils new regulators of atherosclerosis and lipid metabolism through DIAPH1.

Functional characterization of interleukin 4 and retinoic acid signaling crosstalk during alternative macrophage activation.

Retinoic acid possesses potent immunomodulatory properties in various cell types, including macrophages. In this study, we first investigated the effects at the transcriptional and functional levels of exogenous retinoic acid in murine bone marrow-derived macrophages (BMDMs) in the presence or absence of interleukin 4 (IL4), a cytokine with potent anti-inflammatory properties. We examined the effect of IL4 on vitamin A homeostasis in macrophages by quantifying retinoid synthesis and secretion. Our RNAseq data show that exogenous retinoic acid synergizes with IL4 to regulate anti-inflammatory pathways such as oxidative phosphorylation and phagocytosis. Efferocytosis and lysosomal degradation assays validated gene expression changes at the functional level. IL4 treatment altered the expression of several genes involved in vitamin A transport and conversion to retinoic acid. Radiolabeling experiments and mass spectrometry assays revealed that IL4 stimulates retinoic acid production and secretion in a signal transducer and activator of transcription 6 (STAT6)-dependent manner. In summary, our studies highlight the key role of exogenous and endogenous retinoic acid in shaping the anti-inflammatory response of macrophages.

The conversion of ß-carotene to vitamin A in adipocytes drives the anti-obesogenic effects of ß-carotene in mice.

OBJECTIVE: The ß-carotene oxygenase 1 (BCO1) is the enzyme responsible for the cleavage of ß-carotene to retinal, the first intermediate in vitamin A formation. Preclinical studies suggest that BCO1 expression is required for dietary ß-carotene to affect lipid metabolism. The goal of this study was to generate a gene therapy strategy that over-expresses BCO1 in the adipose tissue and utilizes the ß-carotene stored in adipocytes to produce vitamin A and reduce obesity. METHODS: We generated a novel adipose-tissue-specific, adeno-associated vector to over-express BCO1 (AT-AAV-BCO1) in murine adipocytes. We tested this vector using a unique model to achieve ß-carotene accumulation in the adipose tissue, in which Bco1-/- mice were fed ß-carotene. An AT-AAV over-expressing green fluorescent protein was utilized as control. We evaluated the adequate delivery route and optimized cellular and organ specificity, dosage, and exposure of our vectors. We also employed morphometric analyses to evaluate the effect of BCO1 expression in adiposity, as well as HPLC and mass spectrometry to quantify ß-carotene and retinoids in tissues, including retinoic acid. RESULTS: AT-AAV-BCO1 infusions in the adipose tissue of the mice resulted in the production of retinoic acid, a vitamin A metabolite with strong effects on gene regulation. AT-AAV-BCO1 treatment also reduced adipose tissue size and adipocyte area by 35% and 30%, respectively. These effects were sex-specific, highlighting the complexity of vitamin A metabolism in mammals. CONCLUSIONS: The over-expression of BCO1 through delivery of an AT-AAV-BCO1 leads to the conversion of ß-carotene to vitamin A in adipocytes, which subsequently results in reduction of adiposity. These studies highlight for the first time the potential of adipose tissue ß-carotene as a target for BCO1 over-expression in the reduction of obesity.

Development and validation of a method to deliver vitamin A to macrophages.

Macrophages are critical players in the development of atherosclerotic lesions, where they promote local and systemic inflammation. Macrophages engulf lipoproteins and cell debris upon entry into the arterial wall, becoming lipid-laden foam cells. While most lipids found in foam cells are triglyceride and cholesterol, these cells accumulate several other lipids with bioactive properties, such as vitamin A and carotenoids. Vitamin A has strong immunomodulatory actions in macrophages and other immune cells. For example, macrophages release vitamin A as retinoic acid to modulate T cell differentiation, but the implication of intracellular vitamin A stores in this process remains elusive due to the lack of an adequate experimental model to load vitamin A into macrophages. The purpose of this study was to develop a reliable method to deliver vitamin A to cultured murine macrophages. Our results show that thioglycolate-elicited peritoneal macrophages fail to take up significant levels of vitamin A when provided as free retinol. Cultured macrophages and macrophages in the peritoneal cavity can take up retinyl esters, either as retinyl ester-loaded serum or retinyl esters infused directly into the peritoneal cavity. HPLC analyses in macrophage lysates revealed that the intraperitoneal injection method results in a fourfold greater vitamin A loading efficiency than retinyl ester-loaded serum added to cultured cells. These two alternative methods provide an efficient and reliable methodology to load macrophages with vitamin A for downstream applications such as studies of gene regulation trafficking of intracellular vitamin A, and vitamin A release from macrophages.

Psychological Distress, Burnout, and Academic Performance in First Year College Students.

BACKGROUND: The first years of university can be very challenging for students. Previous research has focused on the study of the prevalence of burnout and of psychological distress in medical students. The aim of this study was to investigate the prevalence of psychological symptoms and burnout reported by first-year students, the relationship between these variables and their academic performance, and the differences between health and non-health sciences students. METHODS: An observational study with a cross-sectional design was performed. Students of health sciences (medicine, nursing, physiotherapy, psychology), and non-health sciences (biology, social sciences, business management, and engineering) undergraduate programs completed the Brief Symptom Inventory (BSI-18) and the Maslach Burnout Inventory-Student Survey (MBI-SS). Students' grades for the first semester were collected. RESULTS: A sample of 506 students participated. Prevalence of psychological distress was 27.1% and burnout was 7.3%. Academic performance was unaffected in relation to either psychological distress or burnout. Non-health sciences students showed a greater risk of depression. CONCLUSIONS: This study provides evidence of the high prevalence of psychological distress in the first year of college. Even when burnout prevalence was low, the results suggest the need to introduce prevention programs to improve the psychological wellbeing of these students.

Fenretinide inhibits vitamin A formation from ß-carotene and regulates carotenoid levels in mice.

N-[4-hydroxyphenyl]retinamide, commonly known as fenretinide, a synthetic retinoid with pleiotropic benefits for human health, is currently utilized in clinical trials for cancer, cystic fibrosis, and COVID-19. However, fenretinide reduces plasma vitamin A levels by interacting with retinol-binding protein 4 (RBP4), which often results in reversible night blindness in patients. Cell culture and in vitro studies show that fenretinide binds and inhibits the activity of ß-carotene oxygenase 1 (BCO1), the enzyme responsible for endogenous vitamin A formation. Whether fenretinide inhibits vitamin A synthesis in mammals, however, remains unknown. The goal of this study was to determine if the inhibition of BCO1 by fenretinide affects vitamin A formation in mice fed ß-carotene. Our results show that wild-type mice treated with fenretinide for ten days had a reduction in tissue vitamin A stores accompanied by a two-fold increase in ß-carotene in plasma (P < 0.01) and several tissues. These effects persisted in RBP4-deficient mice and were independent of changes in intestinal ß-carotene absorption, suggesting that fenretinide inhibits vitamin A synthesis in mice. Using Bco1-/- and Bco2-/- mice we also show that fenretinide regulates intestinal carotenoid and vitamin E uptake by activating vitamin A signaling during short-term vitamin A deficiency. This study provides a deeper understanding of the impact of fenretinide on vitamin A, carotenoid, and vitamin E homeostasis, which is crucial for the pharmacological utilization of this retinoid.

Factors influencing student choice of a degree in physiotherapy: a population-based study in Catalonia (Spain).

BACKGROUND: In other healthcare professions, there has been extensive research into students' motivation, but studies aiming to determine what leads individuals to choose a degree in physiotherapy are scarce. This research study had three main objectives: to obtain a sociodemographic profile of first-year physiotherapy students in Catalonia; to determine the factors that lead individuals to choose a degree in physiotherapy; and to determine potential differences, according to gender and country of origin. METHODS: This is an observational, cross-sectional, multicentre study. Data were collected by means of a self-administered, ad-hoc questionnaire, consisting of 15 Likert scale questions, options ranging from "not influencing at all -1-" to "extremely influencing -5-". Ten out of the twelve universities in Catalonia (Spain) that offer a degree in physiotherapy participated in this study. The sample consisted of 941 first-year physiotherapy students (55.2% men; mean age 20.1, SD: 3.4). RESULTS: The most determinant factors leading individuals to pursue a degree in physiotherapy were: helping others (95.6%); the relationship between physiotherapy and sports (79%); physiotherapy involving manual work (76.4%); and it being perceived as providing multiple job opportunities (75.9%). Male and French students were attracted due to its relation to sports (MD = 0.369, p < 0.001 and MD = 0.130, p < 0.027), perception of it being an easy degree (MD = 0.148, p < 0.001 and MD = 0.091, p < 0.037), admiration for a known physiotherapist (MD = 0.223, p = 0.006 and MD = 0.265, p = 0.001), employability (MD = 0.297, p < 0.001 and MD = 0.706, p < 0.001), good income (MD = 0.190, p = 0.002 and MD = 0.609, p < 0.001) and social recognition (MD = 0.164, p = 0.011 and MD = 0.286, p < 0.001). Helping others (MD = -0.149, p < 0.001) and interest in the sciences (MD = -0.164, p = 0.030) were more determinant for female students. Male students were more guided by recommendation (MD = 0.234, p = 0.001) and to complement previous studies (MD = 0.237, p = 0.016). French students tended to present more interest in the selection of physiotherapy as a wish since childhood (MD = 0.595, p < 0.001), due to its multiple job opportunities (MD = 0.427, p < 0.001) and because of manual work, and did not choose it to complement previous studies (MD = -1.122, p < 0.001). CONCLUSIONS: The desire to help and care for others, the relation to sports, and involving manual work are the predominant factors that lead students to pursue a degree in physiotherapy. Female students favour helping others and science, whereas male students favour its relation to sports, complementing studies, social factors (admiration, recommendation, friendship) and socioeconomic determinants such as employability, good income or social recognition. When compared to Spanish students, French students were more motivated by its connection to sports, social and socioeconomic factors and some vocational determinants such as being a wish since childhood and interest in a manual profession.

Lycopene: A Critical Review of Digestion, Absorption, Metabolism, and Excretion.

Lycopene is a non-provitamin A carotenoid that exhibits several health benefits. Epidemiological data support a correlation between lycopene intake and the attenuation of several chronic diseases, including certain types of cancers and cardiovascular diseases. It is currently unknown whether the beneficial effects are from the native structure of lycopene or its metabolic derivatives: lycopenals, lycopenols, and lycopenoic acids. This literature review focuses on the current research on lycopene digestion, absorption, metabolism, and excretion. This review primarily focuses on in vivo studies because of the labile nature and difficulty of studying carotenoids within in vitro experimental models. The studies presented address tissue accumulation of lycopene, the modification of bioavailability due to genetic and dietary factors, and lycopene cleavage by the enzymes ß-carotene oxygenase 1 (BCO1) and ß-carotene oxygenase 2 (BCO2). The current literature suggests that the majority of lycopene is cleaved eccentrically by BCO2, yet further research is needed to probe the enzymatic cleavage activity at the tissue level. Additionally, results indicate that single nucleotide polymorphisms and dietary fat influence lycopene absorption and thus modify its health effects. Further research exploring the metabolism of lycopene, the mechanisms related to its health benefits, and optimal diet composition to increase the bioavailability is required.

Short-Term Acyl-CoA:Cholesterol Acyltransferase Inhibition, Combined with Apoprotein A1 Overexpression, Promotes Atherosclerosis Inflammation Resolution in Mice.

Acyl-CoA:cholesterol acyltransferase (ACAT) mediates cellular cholesterol esterification. In atherosclerotic plaque macrophages, ACAT promotes cholesteryl ester accumulation, resulting in foam cell formation and atherosclerosis progression. Its complete inactivation in mice, however, showed toxic effects because of an excess of free cholesterol (FC) in macrophages, which can cause endoplasmic reticulum stress, cholesterol crystal formation, and inflammasome activation. Our previous studies showed that long-term partial ACAT inhibition, achieved by dietary supplementation with Fujirebio F1394, delays atherosclerosis progression in apoprotein E-deficient (Apoe -/-) mice by reducing plaque foam cell formation without inflammatory or toxic effects. Here, we determined whether short-term partial inhibition of ACAT, in combination with an enhanced systemic FC acceptor capacity, has synergistic benefits. Thus, we crossbred Apoe -/- with human apoprotein A1-transgenic (APOA1 tg/tg) mice, which have elevated cholesterol-effluxing high-density lipoprotein particles, and subjected Apoe -/- and APOA1 tg/tg/Apoe -/- mice to an atherogenic diet to develop advanced plaques. Then mice were either euthanized (baseline) or fed purified standard diet with or without F1394 for 4 more weeks. Plaques of APOA1 tg/tg/Apoe -/- mice fed F1394 showed a 60% reduction of macrophages accompanied by multiple other benefits, such as reduced inflammation and favorable changes in extracellular composition, in comparison with Apoe -/- baseline mice. In addition, there was no accumulation of cholesterol crystals or signs of toxicity. Overall, these results show that short-term partial ACAT inhibition, coupled to increased cholesterol efflux capacity, favorably remodels atherosclerosis lesions, supporting the potential of these combined therapies in the treatment of advanced atherosclerosis. SIGNIFICANCE STATEMENT: Short-term pharmacological inhibition of acyl-CoA:cholesterol acyltransferase-mediated cholesterol esterification, in combination with increased free cholesterol efflux acceptors, has positive effects in mice by 1) reducing the inflammatory state of the plaque macrophages and 2) favoring compositional changes associated with plaque stabilization. These effects occur without toxicity, showing the potential of these combined therapies in the treatment of advanced atherosclerosis.

ß-Carotene conversion to vitamin A delays atherosclerosis progression by decreasing hepatic lipid secretion in mice.

Atherosclerosis is characterized by the pathological accumulation of cholesterol-laden macrophages in the arterial wall. Atherosclerosis is also the main underlying cause of CVDs, and its development is largely driven by elevated plasma cholesterol. Strong epidemiological data find an inverse association between plasma ß-carotene with atherosclerosis, and we recently showed that ß-carotene oxygenase 1 (BCO1) activity, responsible for ß-carotene cleavage to vitamin A, is associated with reduced plasma cholesterol in humans and mice. In this study, we explore whether intact ß-carotene or vitamin A affects atherosclerosis progression in the atheroprone LDLR-deficient mice. Compared with control-fed Ldlr-/- mice, ß-carotene-supplemented mice showed reduced atherosclerotic lesion size at the level of the aortic root and reduced plasma cholesterol levels. These changes were absent in Ldlr-/- /Bco1-/- mice despite accumulating ß-carotene in plasma and atherosclerotic lesions. We discarded the implication of myeloid BCO1 in the development of atherosclerosis by performing bone marrow transplant experiments. Lipid production assays found that retinoic acid, the active form of vitamin A, reduced the secretion of newly synthetized triglyceride and cholesteryl ester in cell culture and mice. Overall, our findings provide insights into the role of BCO1 activity and vitamin A in atherosclerosis progression through the regulation of hepatic lipid metabolism.

ß-Carotene Oxygenase 1 Activity Modulates Circulating Cholesterol Concentrations in Mice and Humans.

BACKGROUND: Plasma cholesterol is one of the strongest risk factors associated with the development of atherosclerotic cardiovascular disease (ASCVD) and myocardial infarction. Human studies suggest that elevated plasma ß-carotene is associated with reductions in circulating cholesterol and the risk of myocardial infarction. The molecular mechanisms underlying these observations are unknown. OBJECTIVE: The objective of this study was to determine the impact of dietary ß-carotene and the activity of ß-carotene oxygenase 1 (BCO1), which is the enzyme responsible for the conversion of ß-carotene to vitamin A, on circulating cholesterol concentration. METHODS: In our preclinical study, we compared the effects of a 10-d intervention with a diet containing 50 mg/kg of ß-carotene on plasma cholesterol in 5-wk-old male and female C57 Black 6 wild-type and congenic BCO1-deficient mice. In our clinical study, we aimed to determine whether 5 common small nucleotide polymorphisms located in the BCO1 locus affected serum cholesterol concentrations in a population of young Mexican adults from the Universities of San Luis Potosí and Illinois: A Multidisciplinary Investigation on Genetics, Obesity, and Social-Environment (UP AMIGOS) cohort. RESULTS: Upon ß-carotene feeding, Bco1-/- mice accumulated >20-fold greater plasma ß-carotene and had ∼30 mg/dL increased circulating total cholesterol (P < 0.01) and non-HDL cholesterol (P < 0.01) than wild-type congenic mice. Our results in the UP AMIGOS cohort show that the rs6564851 allele of BCO1, which has been linked to BCO1 enzymatic activity, was associated with a reduction in 10 mg/dL total cholesterol concentrations (P = 0.009) when adjusted for vitamin A and carotenoid intakes. Non-HDL-cholesterol concentration was also reduced by 10 mg/dL when the data were adjusted for vitamin A and total carotenoid intakes (P = 0.002), or vitamin A and ß-carotene intakes (P = 0.002). CONCLUSIONS: Overall, our results in mice and young adults show that BCO1 activity impacts circulating cholesterol concentration, linking vitamin A formation with the risk of developing ASCVD.