Xanthohumol, a hop-derived prenylated flavonoid, promotes macrophage reverse cholesterol transport

Beneficial Effects of Xanthohumol on Metabolic Syndrome: Evidence from In Vitro and Animal Model Studies

Metabolic syndrome refers to the simultaneous occurrence of several disorders that have been associated with other co-morbidities, such as a pro-inflammatory state and non-alcoholic fatty liver disease. Nowadays, it is a growing public health problem that contributes to the development of non-communicable diseases, such as type 2 diabetes, cardiovascular disease, and cognitive deficits among others. Its incidence has been related to modifiable lifestyle factors, mainly dietary patterns and physical activity. In addition, numerous studies have observed the potential beneficial effects of polyphenols in the prevention and treatment of metabolic syndrome components in both animals and humans. In this line, the aim of this review is to present the scientific evidence available about the beneficial effects of the phenolic compound xanthohumol in the prevention and/or treatment of obesity, dyslipidemia, insulin resistance, and fatty liver, which are important components of metabolic syndrome. All the potential beneficial effects described in this manuscript have been observed in vitro and in animal models, there are no published clinical trials in this context yet.

The processed Euphorbia lathyris L. alleviates the inflammatory injury via regulating LXRα/ABCA1 expression and TLR4 positioning to lipid rafts

Euphorbia lathyris L. (EL) is a traditional poisonous herbal medicine used to treat dropsy, ascites, amenorrhea, anuria and constipation. Processing to reduce toxicity of EL is essential for its safe and effective application. However, there is little known regarding the molecular mechanism of reducing toxicity after EL processing. This research aimed to screen the differential markers for EL and PEL, explore the differential mechanisms of inflammatory injury induced by EL and processed EL (PEL) to expound the mechanism of alleviating toxicity after EL processing. The results showed that 15 potential biomarkers, mainly belonging to diterpenoids, were screened to distinguish EL from PEL. EL promoted the expressions of TLR4, NLRP3, NF-κB p65, IL-1β and TNF-α, increased lipid rafts abundance and promoted TLR4 positioning to lipid rafts. Meanwhile, EL decreased LXRα and ABCA1 expression, and reduced cholesterol efflux. In contrast to EL, the effects of PEL on these indicators were markedly weakened. In addition, Euphorbia factors L1, L2, and L3 affected LXRα, ABCA1, TLR4, NLRP3, NF-κB p65, TNF-α and IL-1β expression, influenced cholesterol efflux and lipid rafts abundance, and interfered with the colocalization of TLR4 and lipid rafts. The inflammatory injury caused by processed EL was significantly weaker than that caused by crude EL, and reduction of Euphorbia factors L1, L2, and L3 as well as attenuation of inflammatory injury participated in processing-based detoxification of EL. Our results provide valuable insights into the attenuated mechanism of EL processing and will guide future research on the processing mechanism of toxic traditional Chinese medicine.

Role of CETP, PCSK-9, and CYP7-alpha in cholesterol metabolism: Potential targets for natural products in managing hypercholesterolemia

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide, primarily affecting the heart and blood vessels, with atherosclerosis being a major contributing factor to their onset. Epidemiological and clinical studies have linked high levels of low-density lipoprotein (LDL) emanating from distorted cholesterol homeostasis as its major predisposing factor. Cholesterol homeostasis, which involves maintaining the balance in body cholesterol level, is mediated by several proteins or receptors, transcription factors, and even genes, regulating cholesterol influx (through dietary intake or de novo synthesis) and efflux (by their conversion to bile acids). Previous knowledge about CVDs management has evolved around modulating these receptors' activities through synthetic small molecules/antibodies, with limited interest in natural products. The central roles of the cholesteryl ester transfer protein (CETP), proprotein convertase subtilisin/kexin type 9 (PCSK9), and cytochrome P450 family 7 subfamily A member 1 (CYP7A1), among other proteins or receptors, have fostered growing scientific interests in understanding more on their regulatory activities and potential as drug targets. We present up-to-date knowledge on the contributions of CETP, PCSK9, and CYP7A1 toward CVDs, highlighting the clinical successes and failures of small molecules/antibodies to modulate their activities. In recommendation for a new direction to improve cardiovascular health, we have presented recent findings on natural products (including functional food, plant extracts, phytochemicals, bioactive peptides, and therapeutic carbohydrates) that also modulate the activities of CETP, PCSK-9, and CYP7A1, and emphasized the need for more research efforts redirected toward unraveling more on natural products potentials even at clinical trial level for CVD management.

Anti-Atherosclerosis and Anti-Hyperlipidemia Functions of Terminalia catappa Fruit

Background: Atherosclerosis is a chronic pathological condition that has remained clinically silent for decades, and the epidemic has continued to be on the rise due to risk factors, including diet, lifestyle, hyperlipidemia, pathogenic microorganisms, and aging. Using various synthetic drugs in treating atherosclerosis is associated with a high risk of myositis, angioedema, myoglobinuria, and acute renal failure. Various side effects of the available drugs have been reported; attempts are underway to explore natural sources with antiatherosclerotic activity. Aim and objective: Using a diet-induced atherosclerosis rat model, the current study tested the hypothesis of antiatherosclerotic and antihyperlipidemic roles of Terminalia catappa fruit extracts. Materials and Methods: Atherosclerosis in Wistar rats was induced using an atherogenic diet. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (AP), creatine kinase (CK), and lactate dehydrogenase (LDH) were determined using analytical kits. Results: Quantitative phytochemical analysis of the extracts demonstrated that the plant had flavonoids, saponins, tannins, terpenoids, alkaloids, cardiac glycosides, sterols, phenols, and anthraquinones. Diet-induced atherogenic Wistar rats showed a significant (p < 0.05) increase in total cholesterol, triglyceride, low-density lipoprotein cholesterol, and very low-density lipoprotein cholesterol compared to the healthy control group; however, the atherogenic lipid profile was reversed by the treatment of T. catappa fruit extracts. The biochemical experiments demonstrate that T. catappa fruit extracts have an antihyperlipidaemic effect, shown by a decreased coronary risk index and the atherogenic index, and an increased cardioprotective index, compared to disease control. Conclusion: The current study indicates that T. catappa fruit extracts may contain bioactive molecules to treat atherosclerosis.

HDL Functions-Current Status and Future Perspectives

Cardiovascular disease (CVD) is the leading cause of death in Western countries. A low HDL-C is associated with the development of CVD. However, recent epidemiology studies have shown U-shaped curves between HDL-C and CVD mortality, with paradoxically increased CVD mortality in patients with extremely high HDL-C levels. Furthermore, HDL-C raising therapy using nicotinic acids or CETP inhibitors mostly failed to reduce CVD events. Based on this background, HDL functions rather than HDL-C could be a novel biomarker; research on the clinical utility of HDL functionality is ongoing. In this review, we summarize the current status of HDL functions and their future perspectives from the findings of basic research and clinical trials.

Recombinant Humanized IgG1 Antibody Promotes Reverse Cholesterol Transport through FcRn-ERK1/2-PPARα Pathway in Hepatocytes

Hyperlipidemia-associated lipid disorders are considered the cause of atherosclerotic cardiovascular disease. Reverse cholesterol transport (RCT) is a mechanism by which excess peripheral cholesterol is transported to the liver and further converted into bile acid for excretion from the body in feces, which contributes to reducing hyperlipidemia as well as cardiovascular disease. We previously found that the recombinant humanized IgG1 antibody promotes macrophages to engulf lipids and increases cholesterol efflux to high-density lipoprotein (HDL) through ATP-binding cassette sub-family A1 (ABCA1), one of the key proteins related to RCT. In the present study, we explored other RCT related proteins expression on hepatocytes, including scavenger receptor class B type I (SR-BI), apolipoprotein A-I (ApoA-I), and apolipoprotein A-II (ApoA-II), and its modulation mechanism involved. We confirmed that the recombinant humanized IgG1 antibody selectively activated ERK1/2 to upregulate SR-BI, ApoA-I, and ApoA-II expression in mice liver and human hepatocellular carcinoma cell lines HepG2 cells. The rate-limiting enzymes of bile acid synthesis, including cholesterol 7α-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1), exhibited a significant increase when treated with the recombinant humanized IgG1 antibody, as well as increased excretion of bile acids in feces. Besides, abolishment or mutation of peroxisome proliferator-activated receptor α (PPARα)/RXR binding site on SR-BI promoter eliminated SR-BI reporter gene luciferase activity even in the presence of the recombinant humanized IgG1 antibody. Knock down the neonatal Fc receptor (FcRn) on hepatocytes impaired the effect of recombinant humanized IgG1 antibody on activation of ERK1/2, as well as upregulation of SR-BI, ApoA-I, and ApoA-II expression. In conclusion, one of the mechanisms on the recombinant humanized IgG1 antibody attenuates hyperlipidemia in ApoE^-/- mice model fed with high-fat-diet might be through reinforcement of liver RCT function in an FcRn-ERK1/2-PPARα dependent manner.

Isochlorogenic Acid C Alleviates High-Fat Diet-Induced Hyperlipemia by Promoting Cholesterol Reverse Transport

Background: Promoting cholesterol reverse transport (RCT) has been proven to be a promising hyperlipidemia therapy since it is more effective for the treatment of atherosclerosis (AS) caused by hyperlipidemia. Liver X receptor (LXR) agonists can accelerate RCT, but most of them trigger undesirable liver steatosis due to the activation of liver LXRα.

Aim: We aim to figure out whether isochlorogenic acid C (ICAC) facilitates RCT without causing hepatic steatosis.

Methods:In vitro study, we established foam macrophages and macrophages with loaded NBD-cholesterol models to investigate the competence of RCT promoting ICAC. RT-qPCR and Western blot were used to verify ICAC’s regulation of RCT and NF-κB inflammatory pathways. In this in vivo study, male 6-week-old C57BL/6 mice were fed a high-fat diet (HFD) to investigate ICAC’s anti-hyperlipidemic effect and its functions in regulating RCT. The anti-hyperlipidemic effect of ICAC was evaluated by blood and liver lipid levels, liver hematoxylin, oil red o staining, and liver coefficient. Finally, mRNA levels of genes involved in RCT and inflammation pathways in the liver and intestine were detected by RT-qPCR.

Results: ICAC prevented macrophages from foaming by up-regulating the LXRα mediated RCT pathway and down-regulating expression of the cholesterol absorption genes LDLR and CD36, as well as suppressing iNOS, COX2, and IL-1β inflammatory factors. In HFD-fed mice, ICAC significantly lowered the lipid level both in the serum and the liver. Mechanistic studies showed that ICAC strengthened the RCT pathway in the liver and intestine but didn’t affect liver LXRα. Furthermore, ICAC impeded both adipogenesis and the inflammatory response in the liver.

Conclusion: ICAC accelerated RCT without affecting liver LXRα, thus resulting in a lipid-lowering effect without increasing liver adipogenesis. Our results indicated that ICAC could be a new RCT promoter for hyperlipidemia treatment without causing liver steatosis.

Bioavailability and Cardiometabolic Effects of Xanthohumol: Evidence from Animal and Human Studies

Xanthohumol is the main prenylflavonoid in hops and has been associated with a wide range of health benefits, due to its anti-inflammatory, anti-oxidative, and cancer-preventive properties. Increasing evidence suggests that xanthohumol positively affects biomarkers associated with metabolic syndrome and cardiovascular diseases (CVDs). This review summarizes the effects of xanthohumol supplementation on body weight, lipid and glucose metabolism, systemic inflammation, and redox status. In addition, it provides insights into the pharmacokinetics of xanthohumol intake. Animal studies show that xanthohumol exerts beneficial effects on body weight, lipid profile, glucose metabolism, and other biochemical parameters associated with metabolic syndrome and CVDs. Although in vitro studies are increasingly elucidating the responsible mechanisms, the overall in vivo results are currently inconsistent and quantitatively insufficient. Pharmacokinetic and safety studies confirm that intake of xanthohumol is safe and well tolerated in both animals and humans. However, little is known about the metabolism of xanthohumol in the human body, and even less about its effects on body weight and CVD risk factors. There is an urgent need for studies investigating whether the effects of xanthohumol on body weight and cardiometabolic parameters observed in animal studies are reproducible in humans, and what dosage, formulation, and intervention period are required. This article is protected by copyright. All rights reserved.

Xanthohumol for Human Malignancies: Chemistry, Pharmacokinetics and Molecular Targets

Xanthohumol (XH) is an important prenylated flavonoid that is found within the inflorescence of Humulus lupulus L. (Hop plant). XH is an important ingredient in beer and is considered a significant bioactive agent due to its diverse medicinal applications, which include anti-inflammatory, antimicrobial, antioxidant, immunomodulatory, antiviral, antifungal, antigenotoxic, antiangiogenic, and antimalarial effects as well as strong anticancer activity towards various types of cancer cells. XH acts as a wide ranging chemopreventive and anticancer agent, and its isomer, 8-prenylnaringenin, is a phytoestrogen with strong estrogenic activity. The present review focuses on the bioactivity of XH on various types of cancers and its pharmacokinetics. In this paper, we first highlight, in brief, the history and use of hops and then the chemistry and structure–activity relationship of XH. Lastly, we focus on its prominent effects and mechanisms of action on various cancers and its possible use in cancer prevention and treatment. Considering the limited number of available reviews on this subject, our goal is to provide a complete and detailed understanding of the anticancer effects of XH against different cancers.

Effects of phytochemicals on macrophage cholesterol efflux capacity: Impact on atherosclerosis

High-density lipoprotein cholesterol (HDL) is the major promoter of reverse cholesterol transport and efflux of excess cellular cholesterol. The functions of HDL, such as cholesterol efflux, are associated with cardiovascular disease rather than HDL levels. We have reviewed the evidence base on the major classes of phytochemicals, including polyphenols, alkaloids, carotenoids, phytosterols, and fatty acids, and their effects on macrophage cholesterol efflux and its major pathways. Phytochemicals show the potential to improve the efficiency of each of these pathways. The findings are mainly in preclinical studies, and more clinical research is warranted in this area to develop novel clinical applications.

Bitter taste receptor activation by hop-derived bitter components induces gastrointestinal hormone production in enteroendocrine cells

Matured hop bitter acids (MHBA) are bitter acid oxides derived from hops, widely consumed as food ingredients to add bitterness and flavor in beers. Previous studies have suggested a potential gut-brain mechanism in which MHBA simulates enteroendocrine cells to produce cholecystokinin (CCK), a gastrointestinal hormone which activates autonomic nerves, resulting in body fat reduction and cognitive improvement; however, the MHBA recognition site on enteroendocrine cells has not been fully elucidated. In this study, we report that MHBA is recognized by specific human and mouse bitter taste receptors (human TAS2R1, 8, 10 and mouse Tas2r119, 130, 105) using a heterologous receptor expression system in human embryonic kidney 293T cells. In addition, knockdown of each of these receptors using siRNA transfection partially but significantly suppressed an MHBA-induced calcium response and CCK production in enteroendocrine cells. Furthermore, blocking one of the essential taste signaling components, transient receptor potential cation channel subfamily M member 5, remarkably inhibited the MHBA-induced calcium response and CCK production in enteroendocrine cells. Our results demonstrate that specific bitter taste receptor activation by MHBA drives downstream calcium response and CCK production in enteroendocrine cells. These findings reveal a mechanism by which food ingredients derived from hops in beer activate the gut-brain axis for the first time.

LncRNA kcnq1ot1 promotes lipid accumulation and accelerates atherosclerosis via functioning as a ceRNA through the miR-452-3p/HDAC3/ABCA1 axis

Kcnq1 overlapping transcript 1 (kcnq1ot1), an imprinted antisense lncRNA in the kcnq1 locus, acts as a potential contributor to cardiovascular disease, but its role in atherosclerosis remains unknown. The aim of this study was to explore the effects of kcnq1ot1 on atherogenesis and the underlying mechanism. Our results showed that kcnq1ot1 expression was significantly increased in mouse aorta with atherosclerosis and lipid-loaded macrophages. Lentivirus-mediated kcnq1ot1 overexpression markedly increased atherosclerotic plaque area and decreased plasma HDL-C levels and RCT efficiency in apoE^-/- mice fed a Western diet. Upregulation of kcnq1ot1 also reduced the expression of miR-452-3p and ABCA1 but increased HDAC3 levels in mouse aorta and THP-1 macrophages. Accordingly, kcnq1ot1 overexpression inhibited cholesterol efflux and promoted lipid accumulation in THP-1 macrophages. In contrast, kcnq1ot1 knockdown protected against atherosclerosis in apoE^-/- mice and suppressed lipid accumulation in THP-1 macrophages. Mechanistically, kcnq1ot1 enhanced HDAC3 expression by competitively binding to miR-452-3p, thereby inhibiting ABCA1 expression and subsequent cholesterol efflux. Taken together, these findings suggest that kcnq1ot1 promotes macrophage lipid accumulation and accelerates the development of atherosclerosis through the miR-452-3p/HDAC3/ABCA1 pathway.

Improvements in Metabolic Syndrome by Xanthohumol Derivatives Are Linked to Altered Gut Microbiota and Bile Acid Metabolism

SCOPE

Two hydrogenated xanthohumol (XN) derivatives, α,β-dihydro-XN (DXN) and tetrahydro-XN (TXN), improved parameters of metabolic syndrome (MetS), a critical risk factor of cardiovascular disease (CVD) and type 2 diabetes, in a diet-induced obese murine model. It is hypothesized that improvements in obesity and MetS are linked to changes in composition of the gut microbiota, bile acid metabolism, intestinal barrier function, and inflammation.

METHODS AND RESULTS

To test this hypothesis, 16S rRNA genes were sequenced and bile acids were measured in fecal samples from C57BL/6J mice fed a high-fat diet (HFD) or HFD containing XN, DXN or TXN. Expression of genes associated with epithelial barrier function, inflammation, and bile acid metabolism were measured in the colon, white adipose tissue (WAT), and liver, respectively. Administration of XN derivatives decreases intestinal microbiota diversity and abundance-specifically Bacteroidetes and Tenericutes-alters bile acid metabolism, and reduces inflammation. In WAT, TXN supplementation decreases pro-inflammatory gene expression by suppressing macrophage infiltration. Transkingdom network analysis connects changes in the microbiota to improvements in MetS in the host.

CONCLUSION

Changes in the gut microbiota and bile acid metabolism may explain, in part, the improvements in obesity and MetS associated with administration of XN and its derivatives.

Determination of Xanthohumol in Hops, Food Supplements and Beers by HPLC

Xanthohumol (XN) is the main prenylated chalcone present in hops (Humulus lupulus) with high biological activity, and it is of great importance for human health because of its antioxidant, anti-inflammatory, immunosuppressive and chemopreventive properties. This polyphenol can be included in the diet through foods in which hops are used, such as beer or food supplements. Because of their health benefits and the increasing interest of using hops as a novel nutraceutical, the aim of this work was the identification and quantification of XN in different types of samples using a method based on high resolution liquid chromatography with a diode array detector (HPLC-DAD). The method was validated in terms of linearity, limits of detection (LOD) and quantification (LOQ), repeatability and recovery. Acceptable linearity (r² 0.9999), adequate recovery (>90% in the most of cases) and good sensitivity (LOD 16 µg/L) were obtained. Furthermore, the presence of XN in all samples was confirmed using liquid chromatography coupled to mass spectrometry (LC-MS/MS) operated in negative ESI (electrospray system ionization) mode. The concentrations of XN determined in hop flowers and food supplements were above the LOQ, in a range between 0.106 and 12.7 mg/g. Beer may also represent an important source of dietary prenylflavonoids, with between 0.028 and 0.062 mg/L of XN. The results showed that the methodology proposed was suitable for the determination of XN in the different types of samples studied, and the amounts of XN varied significantly according to the selected product.

Xuezhitong capsule, an extract of Allium macrostemon Bunge, exhibits reverse cholesterol transport and accompanies high-density lipoprotein levels to protect against hyperlipidemia in ApoE-/- mice

Background

Xuezhitong capsules (XZT) are derived from Xie Bai and used for abnormal lipid homeostasis treatment through maintained metabolic balance. However, their mechanisms are largely unknown. Here, we mainly assessed the contribution of reverse cholesterol transport (RCT) and the accompanying increase in the high-density lipoprotein (HDL) effects of XZT to cholesterol dysfunction amelioration in mice.

Methods

We assessed serum lipids by using enzymatic kits. We observed atherosclerotic plaque formation by hematoxylin-eosin (HE) and Oil Red O staining. We studied the lipid metabolism, fatty acid synthase (FAS), HDL, low-density lipoprotein receptor (LDLR), triglyceride (TG) metabolic enzyme expression levels, and RCT function in various tissues upon stimulation with high-fat diet, XZT, and some positive drugs by ELISA.

Results

After 34 weeks of high-fat diet administration, blood lipids levels increased because attenuated by XZT treatment (800 and 1,600 mg/kg, i.g.). XZT improved the lipid metabolism instability, induced RCT activation, and subsequently increased the HDL levels in hyperlipidemic mice (P<0.05). FAS (P<0.05) and LDLR (P<0.01) levels also remarkably improved. The effects of XZT were closely associated with RCT activation and the accompanying increase in the HDL levels, as characterized by XZT-induced preservation in ATP-binding cassette transporter member 1 (ABCA1), scavenger receptor class B type 1 (SRB1), acyl coenzyme A: cholesterol acyltransferase (ACAT), lecithin cholesterol acyltransferase (LCAT), apolipoprotein A I (ApoA1) and apolipoprotein B (ApoB). However, XZT showed no effect on high fat diet-activated TG metabolic enzyme expression levels (P>0.05).

Conclusions

XZT are promising drugs in balancing the cholesterol dysfunction from hyperlipidemia through RCT activation and accompanying increase in HDL levels.

Bringing microbiome-drug interaction research into the clinic

Our understanding of the scope and clinical relevance of gut microbiota metabolism of drugs is limited to relatively few biotransformations targeting a subset of therapeutics. Translating microbiome research into the clinic requires, in part, a mechanistic and predictive understanding of microbiome-drug interactions. This review provides an overview of microbiota chemistry that shapes drug efficacy and toxicity. We discuss experimental and computational approaches that attempt to bridge the gap between basic and clinical microbiome research. We highlight the current landscape of preclinical research focused on identifying microbiome-based biomarkers of patient drug response and we describe clinical trials investigating approaches to modulate the microbiome with the goal of improving drug efficacy and safety. We discuss approaches to aggregate clinical and experimental microbiome features into predictive models and review open questions and future directions toward utilizing the gut microbiome to improve drug safety and efficacy.

Prenylated Flavonoids from the Roots and Rhizomes of Sophora tonkinensis and Their Effects on the Expression of Inflammatory Mediators and Proprotein Convertase Subtilisin/Kexin Type 9

Seven new prenylated flavonoids (1-7) and one new prenylated phenylpropiophenone (8) were isolated from roots and rhizomes of Sophora tonkinensis, along with nine known compounds (9-17). The structures 1-8 were elucidated by spectroscopic data analysis and comparison with reported values. Compounds 8 and 12 (7-methoxyebenosin) showed inhibitory activities against nitric oxide production in lipopolysaccharide-induced RAW264.7 cells, with IC₅₀ values of 8.1 and 6.2 μM, respectively. They also significantly lowered expression of CSF2, TNF, and IL-1β. Lonchocarpol A (10) and erybraedin D (16) at concentrations of 20 μM downregulated proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA expression in HepG2 cells. Moreover, erybraedin D (16) inhibited PCSK9 protein synthesis (IC₅₀ 7.8 μM), while simultaneously activating AMP-activated protein kinase and acetyl-CoA carboxylase.

Secretion of a gastrointestinal hormone, cholecystokinin, by hop-derived bitter components activates sympathetic nerves in brown adipose tissue

Matured hop bitter acids (MHBA) are oxidation products from bitter components in hops, which are used widely as food materials to add flavor and bitterness in beer production. Our previous study has shown that MHBA induces thermogenesis in brown adipose tissue (BAT) via sympathetic nerves in rodents and reduces body fat in healthy adults. However, it is unclear how MHBA affects the sympathetic nervous system. In this study, we demonstrate that MHBA treatment of enteroendocrine cells increases Ca²⁺ levels and induces the secretion of the gastrointestinal hormone, cholecystokinin (CCK), in a dose-dependent manner. These effects were eliminated by Ca²⁺ depletion from the medium or blockers of L-type voltage-sensitive Ca²⁺ channels during pretreatment. Induction of CCK secretion by MHBA was also confirmed using isolated rat small intestines. Elevation of the sympathetic nerve activity innervating BAT (BAT-SNA) and BAT temperature by MHBA administration in rats was blocked by pretreatment with a CCK receptor 1 (CCK1R) antagonist. Moreover, the intraperitoneal injection of CCK fragment elevated BAT-SNA, and this increase was blocked by subdiaphragmatic vagotomy. These results demonstrate that MHBA induces CCK secretion in the gastrointestinal tracts and elevates BAT-SNA via CCK1R and vagal afferent nerves. In addition, MHBA increases BAT temperature via CCK1R. Our findings reveal a novel mechanism of the beneficial metabolic effects of food ingredients.

Xanthohumol Blocks Proliferation and Migration of Vascular Smooth Muscle Cells in Vitro and Reduces Neointima Formation in Vivo

Xanthohumol (1) is a principal prenylated chalcone found in hops. The aim of this study was to examine its influence on platelet-derived growth factor (PDGF)-BB-triggered vascular smooth muscle cell (VSMC) proliferation and migration in vitro and on experimentally induced neointima formation in vivo. Quantification of resazurin conversion indicated that 1 can inhibit PDGF-BB-induced VSMC proliferation concentration-dependently (IC₅₀ = 3.49 μM). Furthermore, in a wound-healing assay 1 potently suppresses PDGF-BB-induced VSMC migration at 15 μM. Tested in a mouse femoral artery cuff model, 1 significantly reduces neointima formation. Taken together, we show that 1 represses PDGF-BB-induced VSMC proliferation and migration in vitro as well as neointima formation in vivo. This novel activity suggests 1 as an interesting candidate for further studies addressing a possible therapeutic application to counteract vascular proliferative disease.