Differential effects of red yeast rice, Berberis aristata and Morus alba extracts on PCSK9 and LDL uptake

Hypolipidemic activity of phytochemical combinations: A mechanistic review of preclinical and clinical studies

Hyperlipidemia, a condition characterized by elevated levels of lipids in the blood, poses a significant risk factor for various health disorders, notably cardiovascular diseases. Phytochemical compounds are promising alternatives to the current lipid-lowering drugs, which cause many undesirable effects. Based on in vivo and clinical studies, combining phytochemicals with other phytochemicals, prebiotics, and probiotics and their encapsulation in nanoparticles is more safe and effective for managing hyperlipidemia than monotherapy. To this end, the results obtained and the mechanisms of action of these combinations were examined in detail in this review.

Research on Hepatocyte Regulation of PCSK9-LDLR and Its Related Drug Targets

The prevalence of hyperlipidemia has increased significantly due to genetic, dietary, nutritional and pharmacological factors, and has become one of the most common pathological conditions in humans. Hyperlipidemia can lead to a range of diseases such as atherosclerosis, stroke, coronary heart disease, myocardial infarction, diabetes, and kidney failure, etc. High circulating low-density lipoprotein cholesterol (LDL-C) is one of the causes of hyperlipidemia. LDL-C in the blood binds to LDL receptor (LDLR) and regulates cholesterol homeostasis through endocytosis. In contrast, proprotein convertase subtilisin/kexin type 9 (PCSK9) mediates LDLR degradation via the intracellular and extracellular pathways, leading to hyperlipidemia. Targeting PCSK9-synthesizing transcription factors and downstream molecules are important for development of new lipid-lowering drugs. Clinical trials regarding PCSK9 inhibitors have demonstrated a reduction in atherosclerotic cardiovascular disease events. The purpose of this review was to explore the target and mechanism of intracellular and extracellular pathways in degradation of LDLR and related drugs by PCSK9 in order to open up a new pathway for the development of new lipid-lowering drugs.

The role of natural products as PCSK9 modulators: A review

A variety of mechanisms and drugs have been shown to attenuate cardiovascular disease (CVD) onset and/or progression. Recent researchers have identified a potential role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in modulating lipid metabolism and reducing plasma low density lipoprotein (LDL) levels. PCSK9 is the central protein in the metabolism of LDL cholesterol (LDL-C) owing to its major function in LDL receptor (LDLR) degradation. Due to the close correlation of cardiovascular disease with lipid levels, many in vivo and in vitro investigations are currently underway studying the physiological role of PCSK9. Furthermore, many studies are actively investigating the mechanisms of various compounds that influence lipid associated-disorders and their associated cardiovascular diseases. PCSK9 inhibitors have been shown to have significant impact in the prevention of emerging cardiovascular diseases. Natural products can effectively be used as PCSK9 inhibitors to control lipid levels through various mechanisms. In this review, we evaluate the role of phytochemicals and natural products in the regulation of PCSK9, and their ability to prevent cardiovascular diseases. Moreover, we describe their mechanisms of action, which have not to date been delineated.

A promising therapy for fatty liver disease: PCSK9 inhibitors

BACKGROUND

Fatty liver disease (FLD) poses a significant global health concern worldwide, with its classification into nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) contingent upon the presence or absence of chronic and excessive alcohol consumption. The absence of specific therapeutic interventions tailored to FLD at various stages of the disease renders its treatment exceptionally arduous. Despite the fact that FLD and hyperlipidemia are intimately associated, there is still debate over how lipid-lowering medications affect FLD. Proprotein Convertase Subtilisin/ Kexin type 9 (PCSK9) is a serine protease predominantly synthesized in the liver, which has a crucial impact on cholesterol homeostasis. Research has confirmed that PCSK9 inhibitors have prominent lipid-lowering properties and substantial clinical effectiveness, thereby justifying the need for additional exploration of their potential role in FLD.

PURPOSE

Through a comprehensive literature search, this review is to identify the relationship and related mechanisms between PCSK9, lipid metabolism and FLD. Additionally, it will assess the pharmacological mechanism and applicability of PCSK9 inhibitors (including naturally occurring PCSK9 inhibitors, such as conventional herbal medicines) for the treatment of FLD and serve as a guide for updating the treatment protocol for such conditions.

METHODS

A comprehensive literature search was conducted using several electronic databases, including Pubmed, Medline, Embase, CNKI, Wanfang database and ClinicalTrials.gov, from the inception of the database to 30 Jan 2024. Key words used in the literature search were "fatty liver", "hepatic steatosis", "PCSK9", "traditional Chinese medicine", "herb medicine", "botanical medicine", "clinical trial", "vivo", "vitro", linked with AND/OR. Most of the included studies were within five years.

RESULTS

PCSK9 participates in the regulation of circulating lipids via both LDLR dependent and independent pathways, and there is a potential association with de novo lipogenesis. Major clinical studies have demonstrated a positive correlation between circulating PCSK9 levels and the severity of NAFLD, with elevated levels of circulating PCSK9 observed in individuals exposed to chronic alcohol. Numerous studies have demonstrated the potential of PCSK9 inhibitors to ameliorate non-alcoholic steatohepatitis (NASH), potentially completely alleviate liver steatosis, and diminish liver impairment. In animal experiments, PCSK9 inhibitors have exhibited efficacy in alleviating alcoholic induced liver lipid accumulation and hepatitis. Traditional Chinese medicine such as berberine, curcumin, resveratrol, piceatannol, sauchinone, lupin, quercetin, salidroside, ginkgolide, tanshinone, lunasin, Capsella bursa-pastoris, gypenosides, and Morus alba leaves are the main natural PCS9 inhibitors. Excitingly, by inhibiting transcription, reducing secretion, direct targeting and other pathways, traditional Chinese medicine exert inhibitory effects on PCSK9, thereby exerting potential FLD therapeutic effects.

CONCLUSION

PCSK9 plays an important role in the development of FLD, and PCSK9 inhibitors have demonstrated beneficial effects on lipid regulation and FLD in both preclinical and clinical studies. In addition, some traditional Chinese medicines have improved the disease progression of FLD by inhibiting PCSK9 and anti-inflammatory and antioxidant effects. Consequently, the inhibition of PCSK9 appears to be a promising therapeutic strategy for FLD.

Identification of 4-amino-2-Pyridones as new potent PCSK9 inhibitors: From phenotypic hit discovery to in vivo tolerability

Among the strategies to overcome the underperformance of statins in cardiovascular diseases (CVDs), the development of drugs targeting the Proprotein Convertase Subtilisin-like Kexin type 9 (PCSK9) is considered one of the most promising. However, only anti-PCSK9 biological drugs have been approved to date, and orally available small-molecules for the treatment of hypercholesterolemic conditions are still missing on the market. In the present work, we describe the application of a phenotypic approach to the identification and optimization of 4-amino-2-pyridone derivatives as a new chemotype with anti-PCSK9 activity. Starting from an in-house collection of compounds, functional assays on HepG2 cells followed by a chemistry-driven hit optimization campaign, led to the potent anti-PCSK9 candidate 5c. This compound, at 5 μM, totally blocked PCSK9 secretion from HepG2 cells, significantly increased LDL receptor (LDLR) expression, and acted cooperatively with simvastatin by reducing its induction of PCSK9 expression. Finally, compound 5c also proved to be well tolerated in C57BL/6J mice at the tested concentration (40 mg/kg) with no sign of toxicity or behavior modifications.

The association between circulatory, local pancreatic PCSK9 and type 2 diabetes mellitus: The effects of antidiabetic drugs on PCSK9

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a potent modulator of cholesterol metabolism and plays a crucial role in the normal functioning of pancreatic islets and the progression of diabetes. Islet autocrine PCSK9 deficiency can lead to the enrichment of low-density lipoprotein (LDL) receptor (LDLR) and excessive LDL cholesterol (LDL-C) uptake, subsequently impairing the insulin secretion in β-cells. Circulatory PCSK9 levels are primarily attributed to hepatocyte secretion. Notably, anti-PCSK9 strategies proposed for individuals with hypercholesterolemia chiefly target liver-derived PCSK9; however, these anti-PCSK9 strategies have been associated with the risk of new-onset diabetes mellitus (NODM). In the current review, we highlight a new direction in PCSK9 inhibition therapy strategies: screening candidates for anti-PCSK9 from the drugs used in type 2 diabetes mellitus (T2DM) treatment. We explored the association between circulating, local pancreatic PCSK9 and T2DM, as well as the relationship between PCSK9 monoclonal antibodies and NODM. We discussed the emergence of artificial and natural drugs in recent years, exhibiting dual benefits of antidiabetic activity and PCSK9 reduction, confirming that the diverse effects of these drugs may potentially impact the progression of diabetes and associated disorders, thereby introducing novel avenues and methodologies to enhance disease prognosis.

Nutraceutical approaches to non-alcoholic fatty liver disease (NAFLD): A position paper from the International Lipid Expert Panel (ILEP)

Non-Alcoholic Fatty Liver Disease (NAFLD) is a common condition affecting around 10-25% of the general adult population, 15% of children, and even > 50% of individuals who have type 2 diabetes mellitus. It is a major cause of liver-related morbidity, and cardiovascular (CV) mortality is a common cause of death. In addition to being the initial step of irreversible alterations of the liver parenchyma causing cirrhosis, about 1/6 of those who develop NASH are at risk also developing CV disease (CVD). More recently the acronym MAFLD (Metabolic Associated Fatty Liver Disease) has been preferred by many European and US specialists, providing a clearer message on the metabolic etiology of the disease. The suggestions for the management of NAFLD are like those recommended by guidelines for CVD prevention. In this context, the general approach is to prescribe physical activity and dietary changes the effect weight loss. Lifestyle change in the NAFLD patient has been supplemented in some by the use of nutraceuticals, but the evidence based for these remains uncertain. The aim of this Position Paper was to summarize the clinical evidence relating to the effect of nutraceuticals on NAFLD-related parameters. Our reading of the data is that whilst many nutraceuticals have been studied in relation to NAFLD, none have sufficient evidence to recommend their routine use; robust trials are required to appropriately address efficacy and safety.

Investigating the in vitro mode of action of okra (Abelmoschus esculentus) as hypocholesterolemic, anti-inflammatory, and antioxidant food

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Okra leaf butanol extract and fruit extract induce the LDLR expression in human hepatoma cell line Huh7.

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Okra leaf butanol extract reduced the mRNA levels of proinflammatory cytokines IL-1β, IL-6 and TNF-α in THP1-derived macrophages.

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Okra fruit extract showed a sequestering ability of cholic acid providing an additional mechanism of hypocholesterolemic activity.

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Leaf ethyl acetate extract exerted significant antioxidant activity with IC₅₀ comparable to ascorbic acid.

Okra (Abelmoschus esculentus) have been introduced as food relatively recently in Europe. It is native to India and one of the most important vegetables in Nigeria. The leaves can be consumed but also the fruit is rich in nutrients and bioactive compounds (i.e., dietary fiber, vitamins, oils, polysaccharides, polyphenols) and several health promoting actions have been ascribed, including a lipid-lowering properties. In this work the effects of fruit and leaf extracts on expression of key mediators of cholesterol metabolism, i.e., the low-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9), were investigated in human hepatoma cell line Huh7. Furthermore, effects on proinflammatory cytokines (IL-1β, IL-6 and TNF-α) expressed by THP1-derived macrophages were studied to assess potential anti-inflammatory actions.

Okra fruit extract significantly induced the mRNA and protein levels of the LDLR by 1.4 ± 0.3 and 4.8 ± 1.5-fold, respectively without any significant modification of PCSK9 expression. In addition, fruit extract showed a significant sequestering ability of cholic acid. Leaf butanol extract exerted similar action by inducing the expression of both the LDLR (+3.1 ± 1.6-fold vs control) and PCSK9 (+1.3 ± 0.4-fold vs control). The evaluation of the potential anti-inflammatory effect revealed a significant action of leaf butanol extract with reduced mRNA levels of IL-1β (−28 ± 8 % vs control), IL-6 (−11 ± 1 % vs control) and TNF-α (−43 ± 8 % vs control), while fruit extract did not show any anti-inflammatory activity. Finally, leaf ethyl acetate extract showed a significant antioxidant capacity comparable to ascorbic acid. Taken together, we provided evidence that leaf butanol extract and, more effectively, fruit extract induced the LDLR expression, effect that may explain the previously reported hypocholesterolemic action of okra. In addition, okra’s extracts reduced the expression of pro-inflammatory cytokines from THP1-derived macrophages, an effect that may suggest a vascular protective action of okra.

A Systematic Review on Attenuation of PCSK9 in Relation to Atherogenesis Biomarkers Associated with Natural Products or Plant Bioactive Compounds in In Vitro Studies: A Critique on the Quality and Imprecision of Studies

A systematic review was performed to identify all the related publications describing PCSK9 and atherogenesis biomarkers attenuation associated with a natural product and plant bioactive compounds in in vitro studies. This review emphasized the imprecision and quality of the included research rather than the detailed reporting of the results. Literature searches were conducted in Scopus, PubMed, and Science Direct from 2003 until 2021, following the Cochrane handbook. The screening of titles, abstracts, and full papers was performed by two independent reviewers, followed by data extraction and validity. Study quality and validity were assessed using the Imprecision Tool, Model, and Marker Validity Assessment that has been developed for basic science studies. A total of 403 articles were identified and 31 of those that met the inclusion criteria were selected. 13 different atherogenesis biomarkers in relation to PCSK9 were found, and the most studied biomarkers are LDLR, SREBP, and HNF1α. In terms of quality, our review suggests that the basic science study in investigating atherogenesis biomarkers is deficient in terms of imprecision and validity.

In Vitro and In Vivo Sucrosomial® Berberine Activity on Insulin Resistance

Background: Berberine is a natural alkaloid with hypoglycemic properties. However, its therapeutic use is limited by a very low oral bioavailability. Here we developed a new oral formulation of berberine based on Sucrosomial^® technology and tested its effect on insulin resistance. Methods: Sucrosomial^® berberine was first tested in vitro in the hepatoma cell line Huh7 to assess its effect on proteins involved in glucose homeostasis and insulin resistance. The pharmacokinetics and efficacy on insulin resistance were then studied in C57BL/6 mice fed with standard (SD) and high-fat diet (HFD) for 16 weeks and treated daily during the last 8 weeks with oral gavage of Sucrosomial^® berberine or berberine. Results: Sucrosomial^® berberine did not affect Huh7 cell viability at concentrations up to 40 µM. Incubation of Huh7 with 20 µM of Sucrosomial^® and control berberine induced glucokinase (GK) and the phosphorylation of 5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK), both known targets for the control of insulin resistance. In vivo, we observed an 8-fold higher plasma concentration after 3 weeks of oral administration of 50 mg/kg/day of Sucrosomial^® formulation compared to berberine. HFD, compared to SD, induced insulin resistance in mice as determined by oral glucose tolerance test (OGTT). The treatment with a 6.25 mg/kg/daily dose of Sucrosomial^® berberine significantly reduced the area under the curve (AUC) of OGTT (73,103 ± 8645 vs. 58,830 ± 5597 mg/dL × min), while control berberine produced the same effects at 50 mg/Kg/day (51518 ± 1984 mg/dL × min). Under these conditions, the two formulations resulted in similar berberine plasma concentration in mice. Nevertheless, a different tissue distribution of metabolites was observed with a significant accumulation of reduced, demethylated and glucuronide berberine in the brain after the oral administration of the Sucrosomial^® form. Glucuronide berberine plasma concentration was higher with Sucrosomial^® berberine compared to normal berberine. Finally, we observed similar increases of AMPK phosphorylation in the liver in response to the treatment with Sucrosomial^® berberine and berberine. Conclusions: The Sucrosomial^® formulation is an innovative and effective technology to improve berberine gastrointestinal (GI) absorption with proven in vitro and in vivo activity on insulin resistance.

The Activity of Ten Natural Extracts Combined in a Unique Blend to Maintain Cholesterol Homeostasis-In Vitro Model

BACKGROUND

Hypercholesterolemia is a major cause of cardiovascular disease and statins, the HMGCoA inhibitors, are the most prescribed drugs. Statins reduce the production of hepatic cholesterol, leading to greater expression of the LDL receptor and greater absorption of circulating LDL, reducing peripheral LDL levels. Unfortunately, statins are believed to induce myopathy and other severe diseases. To overcome this problem, safe nutraceuticals with the same activity as statins could hold great promise in the prevention and treatment of hypercholesterolemia. In this study, the anti-cholesterol efficacy of a new nutraceutical, called Esterol10^®, was evaluated.

METHODS

HepG2 cells were used to study the biological mechanisms exerted by Esterol10^® analyzing different processes involved in cholesterol metabolism, also comparing data with Atorvastatin.

RESULTS

Our results indicate that Esterol10^® leads to a reduction in total hepatocyte cholesterol and an improvement in the biosynthesis of free cholesterol and bile acids. Furthermore, the anti-cholesterol activity of Esterol10^® was also confirmed by the modulation of the LDL receptor and by the accumulation of lipids, as well as by the main intracellular pathways involved in the metabolism of cholesterol.

CONCLUSIONS

Esterol10^® is safe and effective with anti-cholesterol activity, potentially providing an alternative therapy to those based on statins for hypercholesterolemia disease.

Berberine attenuates atherosclerotic lesions and hepatic steatosis in ApoE-/- mice by down-regulating PCSK9 via ERK1/2 pathway

Background

It has been demonstrated that berberine (BBR), a kind of alkaloid derived from Chinese herbal medicine, has multiple pharmacological effects on human’s diseases including anti-atherosclerosis action. However, although the previous studies showed that the beneficial impact of BBR on atherosclerosis might be associated with proprotein convertase subtilisin/kexin type 9 (PCSK9), the exact underlying mechanism are not fully determined. The present study aimed to investigate potential mechanisms of anti-atherosclerosis by BBR using ApoE^-/- mice.

Methods

The eight-week mice were divided into five groups: group 1 (wild type C57BL/6J mice with normal diet), group 2 (ApoE^-/- mice with normal diet), group 3 [ApoE^-/- mice with high-fat diet (HFD)], group 4 (ApoE^-/- mice with HFD, and treatment with low dose BBR of 50 mg/kg/d), and group 5 (ApoE^-/- mice with HFD, and treatment with high dose BBR of 100 mg/kg/d). After a 16-week treatment, the blood sample, aorta and liver were collected for lipid analysis, hematoxylin-eosin (HE) or oil red O staining, and Western blotting respectively. Besides, HepG2 Cells were cultured and treated with different concentrations of BBR (0, 5, 25 and 50 µg/mL) for 24 hours. Subsequently, cells were collected for real-time PCR or western blotting assays. Finally, the expression levels of PCSK9, LDL receptor (LDLR), ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and scavenger receptor class B type I (SR-BI) were examined.

Results

Fifty mg/kg/d and 100 mg/kg/d of BBR decreased total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol (LDL-C), and increased high-density lipoprotein cholesterol (HDL-C) level. Moreover, BBR reduced aorta atherosclerotic plaque, and ameliorated lipid deposition in ApoE^-/- mice fed with HFD. Finally, in vitro study showed that BBR promoted intracellular cholesterol efflux, up-regulated LDLR and down-regulated PCSK9 expression via the ERK1/2 pathway in cultured HepG2 cells.

Conclusions

Data indicated that BBR significantly attenuated lipid disorder, reduced aortic plaque formation, and alleviated hepatic lipid accumulation in ApoE^-/- mice fed with HFD, which was associated with down-regulation of PCSK9 through ERK1/2 pathway.

PCSK9 Induces Rat Smooth Muscle Cell Proliferation and Counteracts the Pleiotropic Effects of Simvastatin

Human atherosclerotic plaque contains smooth muscle cells (SMCs) negative for the contractile phenotype (α-smooth muscle actin) but positive for proprotein convertase subtilisin/kexin type 9 (PCSK9). Thus, we generated rat SMCs which overexpressed human PCSK9 (SMCs^PCSK9) with the aim of investigating the role of PCSK9 in the phenotype of SMCs. PCSK9 overexpression in SMCs^PCSK9 led to a significant downregulation of the low-density lipoprotein receptor (Ldlr) as well as transgelin (Sm22α), a marker of the contractile phenotype. The cell proliferation rate of SMCs^PCSK9 was significantly faster than that of the control SMCs (SMCs^puro). Interestingly, overexpression of PCSK9 did not impact the migratory capacity of SMCs in response to 10% FCS, as determined by Boyden's chamber assay. Expression and activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (Hmgcr) was significantly increased in the presence of PCSK9, both in SMC^PCSK9 and after treatment with recombinant PCSK9. The transcriptional activity of sterol regulatory element-binding protein (SREBP) was also increased in the presence of PSCK9, suggesting a direct role of PCSK9 in the control of SRE-responsive genes, like HMGCR. We also observed that cholesterol biosynthesis is elevated in SMC^PCSK9, potentially explaining the increased proliferation observed in these cells. Finally, concentration-dependent experiments with simvastatin demonstrated that SMCs^PCSK9 were partially resistant to the antiproliferative and antimigratory effect of this drug. Taken together, these data further support a direct role of PCSK9 in proliferation, migration, and phenotypic changes in SMCs-pivotal features of atherosclerotic plaque development. We also provide new evidence on the role of PCSK9 in the pharmacological response to statins-gold standard lipid-lowering drugs with pleiotropic action.

Morus alba L. Plant: Bioactive Compounds and Potential as a Functional Food Ingredient

Morus alba L. (M. alba) is a highly adaptable plant that is extensively incorporated in many traditional and Ayurveda medications. Various parts of the plant, such as leaves, fruits, and seeds, possess nutritional and medicinal value. M. alba has abundant phytochemicals, including phenolic acids, flavonoids, flavonols, anthocyanins, macronutrients, vitamins, minerals, and volatile aromatic compounds, indicating its excellent pharmacological abilities. M. alba also contains high nutraceutical values for protein, carbohydrates, fiber, organic acids, vitamins, and minerals, as well as a low lipid value. However, despite its excellent biological properties and nutritional value, M. alba has not been fully considered as a potential functional food ingredient. Therefore, this review reports on the nutrients and bioactive compounds available in M. alba leaves, fruit, and seeds; its nutraceutical properties, functional properties as an ingredient in foodstuffs, and a microencapsulation technique to enhance polyphenol stability. Finally, as scaling up to a bigger production plant is needed to accommodate industrial demand, the study and limitation on an M. alba upscaling process is reviewed.

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.

Cholesterol-Lowering Action of a Novel Nutraceutical Combination in Uremic Rats: Insights into the Molecular Mechanism in a Hepatoma Cell Line

Appropriate nutraceutical combinations may represent a valid approach to prevent vascular calcification associated with chronic kidney disease (CKD). In the present study, we tested the effect of a new nutraceutical combination named RenaTris^®, containing MK-7, magnesium carbonate, and Sucrosomial^® Iron, on vascular calcification in uremic rats. Rats were randomly divided into three groups, i.e. control (high-phosphate diet), uremic (high-phosphate diet containing 0.5% adenine), and supplemented uremic diet (0.5% adenine, MK-7, magnesium carbonate, and Sucrosomial^® Iron). After six weeks, sera and vascular calcification were examined. The uremic diet increased creatinine and phosphate levels and induced extensive vascular calcification. The uremic condition also induced a mild hypercholesterolemic condition (+52% of total cholesterol; p < 0.05). The supplemented uremic diet did not reduce creatinine, phosphate levels, or vascular calcification, however, we observed a significant hypocholesterolemic effect (-18.9% in supplemental uremic vs. uremic diet; p < 0.05). Similar to simvastatin, incubation of cultured human hepatoma cells (Huh7) with MK-7 significantly reduced cholesterol biosynthesis (-38%) and induced 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase and low-density lipoprotein receptor (LDLR) at both mRNA and protein levels. The effect of MK-7 on LDLR was counteracted by the co-incubation with squalene. Unlike simvastatin, MK-7 reduced PCSK9 in Huh7. These results indicated that the new nutraceutical combination significantly impacts cholesterol metabolism and its supplementation may help to control mild hypercholesterolemic conditions in CKD patients.

Antihypertensive phytocomplexes of proven efficacy and well-established use: Mode of action and individual characterization of the active constituents

Hypertension has become the leading risk factor for worldwide cardiovascular diseases. Conventional pharmacological treatment, after both dietary and lifestyle changes, is generally proposed. In this review, we present the antihypertensive properties of phytocomplexes from thirteen plants, long ago widely employed in ethnomedicines and, in recent years, increasingly evaluated for their activity in vitro and in vivo, also in humans, in comparison with synthetic drugs acting on the same systems. Here, we focus on the demonstrated or proposed mechanisms of action of such phytocomplexes and of their constituents proven to exert cardiovascular effects. Almost seventy phytochemicals are described and scientifically sound pertinent literature, published up to now, is summarized. The review emphasizes the therapeutic potential of these natural substances in the treatment of the 'high normal blood pressure' or 'stage 1 hypertension', so-named according to the most recent European and U.S. guidelines, and as a supplementation in more advanced stages of hypertension, however needing further validation by clinical trial intensification.