Hypolipidaemic and anti-atherosclerotic effects of lupin proteins in a rabbit model

Improved digestibility and bioavailability of pea protein following enzymatic treatment and fermentation by lactic acid bacteria

Peas (Pisum sativum L.) have a potential commercial value because of their high protein content, non-GMO status, low allergenicity. This study examined changes in the digestion and absorption properties of enzyme-modified and fermented pea protein (EFPP) produced through enzymatic treatment of pea protein and fermentation with lactic acid bacteria. EFPP was digested 22.50% more than isolated pea protein (IPP) during the first 15 min in vitro digestion model. Based on the Caco-2 cell monolayer model, EFPP showed 38.40% higher bioavailability than IPP. Gel Permeation Chromatography showed that the average molecular weight of EFPP was 98.79% lower than that of IPP. The secondary structure of protein was analyzed by Fourier transform infrared spectrometry and it showed a 53.92% reduction in β-sheet of EFPP than IPP. These results indicate that enzyme treatment and fermentation of pea protein reduced the molecular weight, modified the secondary structure, and improved digestibility and bioavailability.

Microarray analysis identifies human apoA-IMilano and apoA-II as determinants of the liver gene expression related to lipid and energy metabolism

The phenotype of individuals carrying the apolipoprotein A-IMilano (apoA-IM), the mutant form of human apoA-I (apoA-I), is characterized by very low concentrations of HDL and apoA-I, and hypertriglyceridemia. Paradoxically, these subjects are not found to be at increased risk of premature cardiovascular disease compared to controls. Besides, various in vitro and in vivo studies have demonstrated that apoA-IM possesses greater anti-atherosclerotic activity compared to apoA-I. The molecular mechanisms explaining the apoA-IM carrier's phenotype and the apoA-IM higher efficacy are still not fully elucidated. To investigate such mechanisms, we crossed previously generated apoA-I (A-I k-in) or apoA-IM knock-in mice (A-IM k-in) with transgenic mice expressing human apoA-II but lacking murine apoA-I (hA-II) to generate hA-II/A-I k-in, and hA-II/A-IM k-in, respectively. These genetically modified mice completely reproduced the apoA-IM carrier's phenotype, including hypoalphalipoproteinemia and hypertriglyceridemia. Furthermore, by using the microarray methodology, we investigated the intrinsic differences in hepatic gene expression among these k-in mouse lines. The expression of 871, 1,018, 1129 and 764 genes was significantly altered between 1) hA-II/A-I and hA-II/A-IM k-in; 2) A-IM and hA-II/A-IM k-in; 3) A-I and A-IM; 4) A-I and hA-II/A-I k-in liver samples, respectively. Bioinformatics analysis highlighted that the hepatic expression of two genes, Elovl6 and Gatm, related to fatty acid/lipid and energy metabolism, respectively, is influenced by the presence of the apoA-IM natural variant and/or apoA-II.

Multielemental, Nutritional, and Proteomic Characterization of Different Lupinus spp. Genotypes: A Source of Nutrients for Dietary Use

Among grain pulses, lupins have recently gained considerable interest for a number of attractive nutritional attributes relating to their high protein and dietary fiber and negligible starch contents. The seeds of Lupinus albus (cv. Multitalia and Luxor, and the Modica ecotype); L. luteus (cv. Dukat, Mister, and Taper); and L. angustifolius (cv. Sonet) analyzed in this study were deposited within the germplasm collection of the Research Centre for Cereal and Industrial Crops of Acireale and were sowed in East Sicily in 2013/14. The collected seeds were analyzed for their multielemental micro- and macronutrient profiles, resulting in a wide variability between genotypes. Lupin seed flour samples were subjected to a defatting process using supercritical CO₂, with oil yields dependent on the species and genotype. We determined the fatty acid profile and tocopherol content of the lupin oil samples, finding that the total saturated fatty acid quantities of different samples were very close, and the total tocopherol content was about 1500.00 µg/g FW. The proteomic analysis of the defatted lupin seed flours showed substantial equivalence between the cultivars of the same species of Lupinus albus and L. luteus. Moreover, the L. angustifolius proteome map showed the presence of additional spots in comparison to L. albus, corresponding to α-conglutins. Lupin, in addition to being a good source of mineral elements, also contributes vitamin E and, thanks to the very high content of gamma-tocopherols, demonstrates powerful antioxidant activity.

Bioactive Peptides from Lupin (Lupinus angustifolius) Prevent the Early Stages of Atherosclerosis in Western Diet-Fed ApoE-/- Mice

We have previously reported the in vitro hypocholesterolemic, anti-inflammatory, and antioxidant effects of Alcalase-generated lupin protein hydrolysate (LPH). Given that lipoprotein deposition, oxidative stress, and inflammation are the main components of atherogenesis, we characterized the LPH composition, in silico identified LPH-peptides with activities related to atherosclerosis, and evaluated the in vivo LPH effects on atherosclerosis risk factors in a mouse model of atherosclerosis. After 15 min of Alcalase hydrolysis, peptides smaller than 8 kDa were obtained, and 259 peptides out of 278 peptides found showed biological activities related to atherosclerosis risk factors. Furthermore, LPH administration for 12 weeks reduced the plasma lipids, as well as the cardiovascular and atherogenic risk indexes. LPH also increased the total antioxidant capacity, decreased endothelial permeability, inflammatory response, and atherogenic markers. Therefore, this study describes for the first time that LPH prevents the early stages of atherosclerosis.

Potential dual inhibitors of PCSK-9 and HMG-R from natural sources in cardiovascular risk management

Atherosclerotic cardiovascular disease (ASCVD) stands amongst the leading causes of mortality worldwide and has attracted the attention of world's leading pharmaceutical companies in order to tackle such mortalities. The low-density lipoprotein-cholesterol (LDL-C) is considered the most prominent biomarker for the assessment of ASCVD risk. Distinct inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-R), the chief hepatic cholesterogenic enzyme, are being used since last seven decades to manage hypercholesterolemia. On the other hand, discovery and the association of proprotein convertase subtilisin/kexin type-9 (PCSK-9) with increased ASCVD risk have established PCSK-9 as a novel therapeutic target in cardiovascular medicine. PCSK-9 is well reckoned to facilitate the LDL-receptor (LDL-R) degradation and compromised LDL-C clearance leading to the arterial atherosclerotic plaque formation. The currently available HMG-R inhibitors (statins) and PCSK-9 inhibitors (siRNA, anti-sense oligonucleotides, and monoclonal antibodies) have shown great promises in achieving LDL-C lowering goals, however, their life long prescriptions have raised significant concerns. These deficits associated with the synthetic HMG-R and PCSK-9 inhibitors called for the discovery of alternative therapeutic candidates with potential dual HMG-R and PCSK-9 inhibitory activities from natural origins. Therefore, this report firstly describes the mechanistic insights into the cholesterol homeostasis through HMG-R, PCSK-9, and LDL-R functionality and then compiles the pharmacological effects of natural secondary metabolites with special emphasis on their dual HMG-R and PCSK-9 inhibitory action. In conclusion, various natural products exhibit atheroprotective effects via targeting HMG-R and PCSK-9 activities and lipoprotein metabolism, however, further clinical assessments are still warranted prior their approval for ASCVD risk management in hypercholesterolemic patients.

Legumes as Functional Food for Cardiovascular Disease

Legumes are an essential food source worldwide. Their high-quality proteins, complex carbohydrates, dietary fiber, and relatively low-fat content make these an important functional food. Known to possess a multitude of health benefits, legume consumption is associated with the prevention and treatment of cardiovascular diseases (CVD). Legume crude protein isolates and purified peptides possess many cardiopreventive properties. Here, we review selected economically valued legumes, their taxonomy and distribution, biochemical composition, and their protein components and the mechanism(s) of action associated with cardiovascular health. Most of the legume protein studies had shown upregulation of low-density lipoprotein (LDL) receptor leading to increased binding and uptake, in effect significantly reducing total lipid levels in the blood serum and liver. This is followed by decreased biosynthesis of cholesterol and fatty acids. To understand the relationship of identified genes from legume studies, we performed gene network analysis, pathway, and gene ontology (GO) enrichment. Results showed that the genes were functionally interrelated while enrichment and pathway analysis revealed involvement in lipid transport, fatty acid and triglyceride metabolic processes, and regulatory processes. This review is the first attempt to collate all known mechanisms of action of legume proteins associated with cardiovascular health. This also provides a snapshot of possible targets leading to systems-level approaches to further investigate the cardiometabolic potentials of legumes.

Nanostructure, Self-Assembly, Mechanical Properties, and Antioxidant Activity of a Lupin-Derived Peptide Hydrogel

Naturally occurring food peptides are frequently used in the life sciences due to their beneficial effects through their impact on specific biochemical pathways. Furthermore, they are often leveraged for applications in areas as diverse as bioengineering, medicine, agriculture, and even fashion. However, progress toward understanding their self-assembling properties as functional materials are often hindered by their long aromatic and charged residue-enriched sequences encrypted in the parent protein sequence. In this study, we elucidate the nanostructure and the hierarchical self-assembly propensity of a lupin-derived peptide which belongs to the α-conglutin (11S globulin, legumin-like protein), with a straightforward N-terminal biotinylated oligoglycine tag-based methodology for controlling the nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), rheological measurements, and Atomic Force Microscopy (AFM) analyses. By using the biotin tag, we obtained a thixotropic lupin-derived peptide hydrogel (named BT13) with tunable mechanical properties (from 2 to 11 kPa), without impairing its spontaneous formation of β-sheet secondary structures. Lastly, we demonstrated that this hydrogel has antioxidant activity. Altogether, our findings address multiple challenges associated with the development of naturally occurring food peptide-based hydrogels, offering a new tool to both fine tune the mechanical properties and tailor the antioxidant activities, providing new research directions across food chemistry, biochemistry, and bioengineering.

Naturally Occurring PCSK9 Inhibitors

Genetic, epidemiological and pharmacological data have led to the conclusion that antagonizing or inhibiting Proprotein convertase subtilisin/kexin type 9 (PCSK9) reduces cardiovascular events. This clinical outcome is mainly related to the pivotal role of PCSK9 in controlling low-density lipoprotein (LDL) cholesterol levels. The absence of oral and affordable anti-PCSK9 medications has limited the beneficial effects of this new therapeutic option. A possible breakthrough in this field may come from the discovery of new naturally occurring PCSK9 inhibitors as a starting point for the development of oral, small molecules, to be used in combination with statins in order to increase the percentage of patients reaching their LDL-cholesterol target levels. In the present review, we have summarized the current knowledge on natural compounds or extracts that have shown an inhibitory effect on PCSK9, either in experimental or clinical settings. When available, the pharmacodynamic and pharmacokinetic profiles of the listed compounds are described.

Nutritional and Bioactive Compounds in Mexican Lupin Beans Species: A Mini-Review

As a source of bioactive compounds, species of the genus Lupinus are interesting legumes from a nutritional point of view. Although wild species are abundant and represent a potential source of nutrients and biologically active compounds, most research has focused on domesticated and semi-domesticated species, such as Lupinus angustifolius, Lupinus albus, Lupinus luteus, and Lupinus mutabilis. Therefore, in this review, we focus on recent research conducted on the wild Lupinus species of Mexico. The nutritional content of these species is characterized (similar to those of the domesticated species), including proteins (isolates), lipids, minerals, dietary fiber, and bioactive compounds, such as oligosaccharides, flavonoids, and alkaloids.

Effects of Fish n-3 PUFAs on Intestinal Microbiota and Immune System

Studies over several decades have documented the beneficial actions of n-3 polyunsaturated fatty acids (PUFAs), which are plentiful in fish oil, in different disease states. Mechanisms responsible for the efficacy of n-3 PUFAs include: (1) Reduction of triglyceride levels; (2) anti-arrhythmic and antithrombotic effects, and (3) resolution of inflammatory processes. The human microbiota project and subsequent studies using next-generation sequencing technology have highlighted that thousands of different microbial species are present in the human gut, and that there has been a significant variability of taxa in the microbiota composition among people. Several factors (gestational age, mode of delivery, diet, sanitation and antibiotic treatment) influence the bacterial community in the human gastrointestinal tract, and among these diet habits play a crucial role. The disturbances in the gut microbiota composition, i.e., gut dysbiosis, have been associated with diseases ranging from localized gastrointestinal disorders to neurologic, respiratory, metabolic, ocular, and cardiovascular illnesses. Many studies have been published about the effects of probiotics and prebiotics on the gut microbiota/microbioma. On the contrary, PUFAs in the gut microbiota have been less well defined. However, experimental studies suggested that gut microbiota, n-3 PUFAs, and host immune cells work together to ensure the intestinal wall integrity. This review discussed current evidence concerning the links among gut microbiota, n-3 PUFAs intake, and human inflammatory disease.

Inhibition of human 3-hydroxy-3-methylglutaryl CoA reductase by peptides leading to cholesterol homeostasis through SREBP2 pathway in HepG2 cells

In mammalian cells, human 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), a rate-limiting endoplasmic reticulum (ER) bonded enzyme, plays a central role in the cholesterol homeostasis via the negative feedback mechanism. The present study indicates that the interactions of novel peptides with the catalytic domain of HMGCR, provides an alternative therapeutic candidate for reducing cholesterol. The potential natural origin of HMGCR peptide inhibitors were filtered from the peptide library using the molecular docking, which revealed three strong candidates for inhibition. This information was used for synthesizing peptides, which were evaluated for inhibition against HMGCR. The stronger docking interactions were confirmed by experimental dissociation constant (K_D) values of 9.1 × 10^-9 M, 1.4 × 10^-8 M and 1.2 × 10^-8 M for peptides NALEPDNRIESEGG (Pep-1), NALEPDNRIES (Pep-2) and PFVKSEPIPETNNE (Pep-3) respectively. The immunological based interactions show a strong evidence of peptide-HMGCR complexes. The LDL uptake showed enhancements after treatments with peptides in the extracellular environment of HepG2 cells, which was further, corroborated through increase in the immunofluorescence signal of the localized LDL-R protein expression on the cell membrane. The results showed that the mRNA and protein expression of transcription factors were significantly up-regulated showing regulation of cholesterol biosynthesis in peptide treated HepG2 cells. The binding of transcription factors, sterol regulatory element (SRE) and cAMP-response element (CRE) on HMGCR promotor further confirms the cholesterol biosynthesis regulation. All the above results suggested a key role of peptide/s in alleviating cholesterol accumulation in tissue via inhibition of rate-limiting HMGCR enzyme.

Effects of Vegetable Proteins on Hypercholesterolemia and Gut Microbiota Modulation

Risk assessment tools, i.e., validated risk prediction algorithms, to estimate the patient's 10-year risk of developing cardiovascular disease (CVD) should be used to identify high-risk people for primary prevention. Current evidence confirms that appropriate monitoring and control of risk factors either reduces the likelihood of CVD or slows down its progression. It is thus crucial that all health professionals make appropriate use of all the available intervention strategies to control risk factors: from dietary improvement and adequate physical activity to the use of functional foods, food supplements, and drugs. The gut microbiota, which encompasses 1 × 1014 resident microorganisms, has been recently recognized as a contributing factor in the development of human disease. This review examines the effect of both some vegetable food components belong to the "protein food group" and the underexploited protein-rich hempseed on cholesterolemia and gut microbiota composition.

Cholesterol-Lowering Nutraceuticals Affecting Vascular Function and Cardiovascular Disease Risk

PURPOSE OF REVIEW

The aim of this review is to provide an update on the effects of the dietary supplementation with cholesterol-lowering nutraceuticals and nutraceutical combinations affecting vascular function and CV risk in clinical interventional studies.

RECENT FINDINGS

Current evidence supports the mild-to-moderate cholesterol-lowering efficacy of red yeast rice, berberine, plant sterols, fibers, and some nutraceutical combinations whereas data on the individual cholesterol-lowering action of other nutraceuticals are either less striking or even inconclusive. There is also promising evidence on the vascular protective effects of some of the aforementioned nutraceuticals. However, except for red yeast rice, clinical interventional studies have not investigated their impact on CV outcomes. Evidence of both cholesterol-lowering and vascular protection is a prerogative of few single nutraceuticals and nutraceutical combinations, which may support their clinical use; however, caution on their uncontrolled adoption is necessary as they are freely available on the market and, therefore, subject to potential misuse.

Nutraceutical approaches to metabolic syndrome

Metabolic Syndrome (MetS), affecting at least 30% of adults in the Western World, is characterized by three out of five variables, from high triglycerides, to elevated waist circumference and blood pressure. MetS is not characterized by elevated cholesterolemia, but is rather the consequence of a complex interaction of factors generally leading to increased insulin resistance. Drug treatments are of difficult handling, whereas well-characterized nutraceuticals may offer an effective alternative. Among these, functional foods, e.g. plant proteins, have been shown to improve insulin resistance and reduce triglyceride secretion. Pro- and pre-biotics, that are able to modify intestinal microbiome, reduce absorption of specific nutrients and improve the metabolic handling of energy-rich foods. Finally, specific nutraceuticals have proven to be of benefit, in particular, red-yeast rice, berberine, curcumin as well as vitamin D. All these can improve lipid handling by the liver as well as ameliorate insulin resistance. While lifestyle approaches, such as with the Mediterranean diet, may prove to be too complex for the single patient, better knowledge of selected nutraceuticals and more appropriate formulations leading to improved bioavailability will certainly widen the use of these agents, already in large use for the management of these very frequent patient groups. Key messages Functional foods, e.g. plant proteins, improve insulin resistance. Pro- and pre-biotics improve the metabolic handling of energy-rich foods. Nutraceutical can offer a significant help in handling MetS patients being part of lifestyle recommendations.

Hypocholesterolaemic Activity of Lupin Peptides: Investigation on the Crosstalk between Human Enterocytes and Hepatocytes Using a Co-Culture System Including Caco-2 and HepG2 Cells

Literature indicates that peptic and tryptic peptides derived from the enzymatic hydrolysis of lupin protein are able to modulate cholesterol metabolism in human hepatic HepG2 cells and that part of these peptides are absorbed in a small intestine model based on differentiated human Caco-2 cells. In this paper, a co-culture system, including Caco-2 and HepG2 cells, was investigated with two objectives: (a) to verify whether cholesterol metabolism in HepG2 cells was modified by the peptides absorption through Caco-2 cells; (b) to investigate how lupin peptides influence cholesterol metabolism in Caco-2 cells. The experiments showed that the absorbed peptides, not only maintained their bioactivity on HepG2 cells, but that this activity was improved by the crosstalk of the two cells systems in co-culture. In addition, lupin peptides showed a positive influence on cholesterol metabolism in Caco-2 cells, decreasing the proprotein convertase subtilisin/kexin type 9 (PCSK9) secretion.

Lupin Peptides Modulate the Protein-Protein Interaction of PCSK9 with the Low Density Lipoprotein Receptor in HepG2 Cells

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recently identified as a new useful target for hypercholesterolemia treatment. This work demonstrates that natural peptides, deriving from the hydrolysis of lupin protein and absorbable at intestinal level, are able to inhibit the protein-protein interaction between PCSK9 and the low density lipoprotein receptor (LDLR). In order to sort out the best potential inhibitors among these peptides, a refined in silico model of the PCSK9/LDLR interaction was developed. Docking, molecular dynamics (MD) simulations and peptide binding energy estimations, by MM-GBSA approach, permitted to select the two best candidates among tested peptides that were synthesized and evaluated for their inhibitory activity. The most active was P5 that induced a concentration dependent inhibition of the PCSK9-LDLR binding, with an IC₅₀ value equal to 1.6 ± 0.33 μM. Tested at a 10 μM concentration, this peptide increased by 66 ± 21.4% the ability of HepG2 cells to take up LDL from the extracellular environment.

Proteomics for exploiting diversity of lupin seed storage proteins and their use as nutraceuticals for health and welfare

Lupins have a variety of both traditional and modern uses. In the last decade, reports assessing the benefits of lupin seed proteins have proliferated and, nowadays, the pharmaceutical industry is interested in lupin proteins for human health. Modern genomics and proteomics have hugely contributed to describing the diversity of lupin storage genes and, above all, proteins. Most of these studies have been centered on few edible lupin species. However, Lupinus genus comprises hundreds of species spread throughout the Old and New Worlds, and these resources have been scarcely explored and exploited. We present here a detailed review of the literature on the potential of lupin seed proteins as nutraceuticals, and the use of -omic tools to analyze seed storage polypeptides in main edible lupins and their diversity at the Lupinus inter- and intra-species level. In this sense, proteomics, more than any other, has been a key approach. Proteomics has shown that lupin seed protein diversity, where post-translational modifications yield a large number of peptide variants with a potential concern in bioactivity, goes far beyond gene diversity. The future extended use of second and third generation proteomics should definitely help to go deeper into coverage and characterization of lupin seed proteome.

BIOLOGICAL SIGNIFICANCE

Some important topics concerning storage proteins from lupin seeds are presented and analyzed in an integrated way in this review. Proteomic approaches have been essential in characterizing lupin seed protein diversity, which goes far beyond gene diversity since the protein level adds to the latter differential proteolytic cleavage of conglutin pro-proteins and a diverse array of glycosylation forms and sites. Proteomics has also proved helpful for screening and studying Lupinus germplasm with the future aim of exploiting and improving food production, quality, and nutritional values.

The beneficial roles of Lupineus luteus and lifestyle changes in management of metabolic syndrome: A case study

Metabolic syndrome (MetS) is a cluster of cardiovascular risk factors including obesity, hypertension, dyslipidemia and hyperuricemia. Here, we report a 43-year-old man with obesity, hypertension, hypercholesterolemia, hyperuricemia and mild liver dysfunctions. Lupid (Lupineus luteus) and therapeutic lifestyle change (TLC) were suggested as therapeutic intervention for the present case for 6 months. The body weight, body mass index (BMI), blood pressure, total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), triacylglycerol (TAG), uric acid (UA) and alanine transaminase (ALT) were markedly decreased by 26.85%, 26.95%, 13%, 53.84%, 57.84%, 36.14%, 47.58% and 61.62% respectively, compared to those at baselines. However, high density lipoprotein cholesterol (HDL-C) value was markedly increased by 30.77%. The present results concluded that administration of lupin with TLC is good intervention for prevention and treatment of MetS.

Isolated Conglutin γ from Lupin, but not Phytate, Lowers Serum Cholesterol Without Influencing Vascular Lesion Development in the ApoE-deficient Mouse Model

Conglutin γ and phytate are considered as potential biofunctional compounds of lupin protein isolate, but their impact on vascular health is unknown. This study aimed to investigate the effect of conglutin γ and phytate, respectively, on circulating levels of sterols, markers of cholesterol biosynthesis and minerals, and on the development and progression of aortic lesions in apoE-deficient mice. To this end, mice were fed a western diet with either casein (200 g/kg; served as a control), conglutin γ from L. angustifolius (200 g/kg) or casein (200 g/kg) supplemented with phytate (5 g/kg) for 16 weeks. Here we found that conglutin γ but not phytate was capable of reducing the circulating concentration of cholesterol. Plasma levels of desmosterol and lathosterol as markers of the cholesterol synthesis were not affected, and 7-dehydrocholesterol was even higher in mice fed conglutin γ than in mice fed casein or casein + phytate. All mice developed pronounced aortic lesions, but histological characterization of plaque area and composition showed no differences between the three groups of mice. Conclusively, conglutin γ exerts cholesterol-lowering effects but appears to have no anti-atherosclerotic properties in the apoE-deficient mice. Phytate neither affected plasma cholesterol nor aortic lesion development.

Additive effects of lupin protein and phytic acid on aortic calcification in ApoE deficient mice

Lupin proteins have repeatedly been shown to exhibit lipid lowering properties and reduce aortic calcification in atherosclerosis models. Despite many efforts on its identification, the component which is responsible for the observed effects is still under debate. Phytic acid which is generally associated with lupin protein isolates has currently been described as bioactive plant compound. The objective of the study was to determine the role of associated phytic acid for the described lupin protein effects.

A two-factorial study with ApoE knockout mice was conducted in which mice received lupin protein isolate or casein with or without phytase. Phytic acid was added to the casein diets to a final concentration identical to the lupin protein diets. Here we show that the serum concentrations of cholesterol, lathosterol and desmosterol were lower and the faecal bile acid excretion was higher in the groups fed lupin proteins than in the groups fed casein (p < 0.05). Mice that received the lupin protein diet containing phytic acid were characterized by a lower aortic calcification than mice of the other three groups (p < 0.05). In conclusion, our results show that the cholesterol lowering properties of lupin protein isolate were not caused by phytic acid. However, the hypocalcific action of lupin proteins appears to depend on the combination of lupin proteins and phytic acid.

Lupin peptides lower low-density lipoprotein (LDL) cholesterol through an up-regulation of the LDL receptor/sterol regulatory element binding protein 2 (SREBP2) pathway at HepG2 cell line

Previous experiments in suitable animal models and in mild hypercholesterolemic individuals have shown that the consumption of lupin proteins may be useful for controlling total and low-density lipoprotein (LDL) cholesterol levels. With the objective of providing evidence that peptides deriving from the hydrolysis of lupin proteins may be responsible of the observed activities and for investigating the mechanism of action, HepG2 cells were treated with lupin peptides obtained by either pepsin (P) or trypsin (T) hydrolysis, and molecular and functional investigations were performed on the LDL receptor/SREBP2 pathway. For the first time, this paper provides experimental evidence that lupin peptides are able to interfere with the HMGCoAR activity, up-regulating the LDL receptor (136 and 84% vs the control for P and T peptides, respectively, at 1 mg/mL) and SREBP2 proteins (148 and 73% vs the control for P and T peptides, respectively, at 1 mg/mL) via the activation of PI3K/Akt/GSK3β pathways and increasing the LDL uptake at HepG2 cell line (40 and 50% vs the control for P and T peptides, respectively, at 1 mg/mL). These results may be useful in explaining the activities observed in vivo in animals and humans treated with lupin protein.

The formation of short-chain fatty acids is positively associated with the blood lipid-lowering effect of lupin kernel fiber in moderately hypercholesterolemic adults

Lupin kernel fiber beneficially modifies blood lipids because of its bile acid-binding capacity. The aim of this study was to evaluate the preventive effects of a lupin kernel fiber preparation on cardiovascular diseases and to clarify possible mechanisms. In a randomized, double-blind, controlled crossover trial, 60 moderately hypercholesterolemic adults (plasma total cholesterol: >5.2 mmol/L) passed 3 intervention periods in different orders with a 2-wk washout phase between each. Participants consumed either a high-fiber diet containing 25-g/d lupin kernel fiber (LF) or citrus fiber (CF), or a low-fiber control diet (CD) for 4 wk each. Anthropometric, plasma, and fecal variables were assessed at baseline and after the interventions. Contrary to the CF period, total (9%) and LDL (12%) cholesterol as well as triacylglycerols (10%) were lower after the LF period when compared with the CD period [P ≤ 0.02, adjusted for baseline, age, gender, and body mass index (BMI)]. HDL cholesterol remained unchanged. Moreover, the LF period reduced high-sensitivity C-reactive protein (P = 0.02) and systolic blood pressure (P = 0.01) when compared with baseline. Bile acid binding could not be shown because the excretion of total bile acids remained constant after the high-fiber diets. However, the LF period resulted in an enhanced formation of the main short-chain fatty acids in comparison with the CD period. During the CF period, only acetate increased significantly. Both high-fiber diets led to higher satiety and modified nutritional behavior, resulting in significantly lower body weight, BMI, and waist circumference compared with the CD period. The blood lipid-lowering effects of LF are apparently not a result of bile acid binding. Rather, we hypothesize for the first time, to our knowledge, that the blood lipid-lowering effects of LF may be mainly attributed to the formation of short-chain fatty acids, specifically propionate and acetate. This trial was registered at clinicaltrials.gov as NCT01035086.

In-depth glycoproteomic characterization of γ-conglutin by high-resolution accurate mass spectrometry

The molecular characterization of bioactive food components is necessary for understanding the mechanisms of their beneficial or detrimental effects on human health. This study focused on γ-conglutin, a well-known lupin seed N-glycoprotein with health-promoting properties and controversial allergenic potential. Given the importance of N-glycosylation for the functional and structural characteristics of proteins, we studied the purified protein by a mass spectrometry-based glycoproteomic approach able to identify the structure, micro-heterogeneity and attachment site of the bound N-glycan(s), and to provide extensive coverage of the protein sequence. The peptide/N-glycopeptide mixtures generated by enzymatic digestion (with or without N-deglycosylation) were analyzed by high-resolution accurate mass liquid chromatography-multi-stage mass spectrometry. The four main micro-heterogeneous variants of the single N-glycan bound to γ-conglutin were identified as Man2(Xyl) (Fuc) GlcNAc2, Man3(Xyl) (Fuc) GlcNAc2, GlcNAcMan3(Xyl) (Fuc) GlcNAc2 and GlcNAc 2Man3(Xyl) (Fuc) GlcNAc2. These carry both core β1,2-xylose and core α1-3-fucose (well known Cross-Reactive Carbohydrate Determinants), but corresponding fucose-free variants were also identified as minor components. The N-glycan was proven to reside on Asn131, one of the two potential N-glycosylation sites. The extensive coverage of the γ-conglutin amino acid sequence suggested three alternative N-termini of the small subunit, that were later confirmed by direct-infusion Orbitrap mass spectrometry analysis of the intact subunit.

Hypocholesterolaemic effects of lupin protein and pea protein/fibre combinations in moderately hypercholesterolaemic individuals

The present study was aimed to evaluate the effect of plant proteins (lupin protein or pea protein) and their combinations with soluble fibres (oat fibre or apple pectin) on plasma total and LDL-cholesterol levels. A randomised, double-blind, parallel group design was followed: after a 4-week run-in period, participants were randomised into seven treatment groups, each consisting of twenty-five participants. Each group consumed two bars containing specific protein/fibre combinations: the reference group consumed casein+cellulose; the second and third groups consumed bars containing lupin or pea proteins+cellulose; the fourth and fifth groups consumed bars containing casein and oat fibre or apple pectin; the sixth group and seventh group received bars containing combinations of pea protein and oat fibre or apple pectin, respectively. Bars containing lupin protein+cellulose ( - 116 mg/l, - 4·2%), casein+apple pectin ( - 152 mg/l, - 5·3%), pea protein+oat fibre ( - 135 mg/l, - 4·7%) or pea protein+apple pectin ( - 168 mg/l, - 6·4%) resulted in significant reductions of total cholesterol levels (P<0·05), whereas no cholesterol changes were observed in the subjects consuming the bars containing casein+cellulose, casein+oat fibre or pea protein+cellulose. The present study shows the hypocholesterolaemic activity and potential clinical benefits of consuming lupin protein or combinations of pea protein and a soluble fibre, such as oat fibre or apple pectin.

Cholesterol-lowering effect of dietary Lupinus angustifolius proteins in adult rats through regulation of genes involved in cholesterol homeostasis

In the absence of a clear indication from previous studies, a rat study was designed to evaluate a possible hypolipidaemic effect of Lupinus angustifolius (blue lupin) proteins. Rats were fed for 28days Nath's hypercholesterolaemic diets containing 20% casein or blue lupin proteins. After 14 and 28days of dietary treatment, blue-lupin-fed rats had markedly lower plasma total cholesterol levels than rats fed casein (-53.0% and -55.3%, respectively, p<0.0005). No significant differences were instead observed for triglyceride and HDL-cholesterol levels between the two groups. Lupin-protein-fed rats displayed higher hepatic mRNA levels of SREBP-2, a major transcriptional regulator of intracellular cholesterol levels, and CYP7A1, the rate-limiting enzyme in bile acid biosynthesis (p<0.05). In conclusion, the present study demonstrates a marked cholesterol-lowering activity of proteins from L. angustifolius in rats. Moreover, blue lupin proteins appear to affect cellular lipid homeostasis by up-regulating SREBP-2 and CYP7A1 genes.

Functional foods for dyslipidaemia and cardiovascular risk prevention

A food can be regarded as ‘functional’ if it can demonstrate a beneficial efficacy on one or more target functions in the body in a convincing way. Beyond adequate nutritional qualities, functional foods should either improve the state of health and wellbeing and/or reduce the risk of disease. Functional foods that are marketed with claims of heart disease reduction focus primarily on the major risk factors, i.e. cholesterol, diabetes and hypertension. Some of the most innovative products are designed to be enriched with ‘protective’ ingredients, believed to reduce risk. They may contain, for example, soluble fibre (from oat and psyllium), useful both for lowering cholesterol and blood pressure, or fructans, effective in diabetes. Phytosterols and stanols lower LDL-cholesterol in a dose-dependent manner. Soya protein is more hypocholesterolaemic in subjects with very high initial cholesterol and recent data indicate also favourable activities in the metabolic syndrome.n-3 Fatty acids appear to exert significant hypotriacylglycerolaemic effects, possibly partly responsible for their preventive activity. Dark chocolate is gaining much attention for its multifunctional activities, useful both for the prevention of dyslipidaemia as well as hypertension. Finally, consensus opinions about tea and coffee have not emerged yet, and the benefits of vitamin E, garlic, fenugreek and policosanols in the management of dyslipidaemia and prevention of arterial disease are still controversial.

Lupin protein isolate and cysteine-supplemented casein reduce calcification of atherosclerotic lesions in apoE-deficient mice

Protein from lupin is supposed to have anti-atherogenic effects due to its lipid-lowering properties in laboratory animals. It is further suggested that the amino acid cysteine plays a crucial role in this aspect. The objective of the present study was to compare the effects of lupin protein and cysteine-supplemented casein with those of casein on atherosclerotic lesion development in apoE-deficient mice. For that purpose, thirty mice were fed an egg albumin-based Western-type diet containing test protein (100 g/kg) for 4 months. ApoE-deficient mice fed the lupin protein or the cysteine-supplemented casein had more than 50 % less aortic calcification than mice fed casein (P < 0.05). The quantified lesion area as a percentage of the total surface area, as well as the collagen and fat content of the lesions were not different between the three groups of mice. The concentration of VLDL TAG was higher in mice fed the lupin protein and the cysteine-supplemented casein than in mice fed casein (P < 0.05). The cholesterol concentrations of VLDL, LDL and HDL from mice fed the lupin protein and cysteine-supplemented casein were not different compared with the mice fed casein. Also, the plasma concentrations of homocysteine, Ca, inorganic phosphate, and the activity of glutathione peroxidase in plasma and liver did not differ between the three groups of mice. The present study shows that lupin protein and cysteine-supplemented casein compared with casein reduce the calcification of atherosclerotic lesions in apoE-deficient mice. This effect seems not to be mediated by effects on plasma lipoproteins, homocysteine and circulating minerals.