Probucol plus cilostazol attenuate hypercholesterolemia‑induced exacerbation in ischemic brain injury via anti-inflammatory effects

Naringin reduces fat deposition by promoting the expression of lipolysis and β-oxidation related genes

AIMS

Naringin, a flavonoid present in citrus fruits, has been known for the capacity to reduce lipid synthesis and anti-inflammatory. In this study, we investigated whether naringin increases lipolysis and fatty acid β-oxidation to change fat deposition.

METHODS

In in vivo experiment, obese adult mice (20-weeks-old, n = 18) were divided into control group fed with normal diet and naringin-treated group fed with naringin-supplemented diet (5 g/kg) for 60 days, respectively. In in vitro experiment, differentiated 3T3-L1 adipocytes were treated for four days with or without naringin (100 µg/mL).

RESULTS

Supplementing naringin significantly reduced the body weight, abdominal fat weight, blood total cholesterol content of mice, but did not affect food intake. In addition, naringin decreased levels of pro-inflammatory factors in adipose tissue including interleukin-1β (IL-1β), interleukin-6 (IL-6), and monocyte chemotactic protein 1 (MCP-1). Naringin increased the expression of AMP-activated protein kinase (AMPK), a key factor in cellular energy metabolism, and raised the ratio of p-AMPK/AMPK in mouse liver tissue. The protein expression of hormone-sensitive lipase (HSL), phospho-HSL563 (p-HSL563), p-HSL563/HSL, and adipocyte triglyceride lipase (ATGL) was significantly increased in the adipose tissue of naringin-treated mice. Furthermore, naringin enhanced the expression of fatty acid β-oxidation genes, including carnitine palmitoyl transferase 1 (CPT1), uncoupling protein 2 (UCP2), and acyl-coenzyme A oxidase 1 (AOX1) in mouse adipose tissue. In in vitro experiment, similar findings were observed in differentiated 3T3-L1 adipocytes with naringin treatment. The treatment remarkably reduced intracellular lipid content, increased the number of mitochondria and promoted the gene expression of HSL, ATGL, CPT1, AOX1, and UCP2 and the phosphorylation of HSL protein.

CONCLUSION

Naringin reduced body fat in obese mice and lipid content in differentiated 3T3-L1 adipocytes, which was associated with enhanced AMPK activation and upregulation of the expression of the lipolytic genes HSL, ATGL, and β-oxidation genes CPT1, AOX1, and UCP2.

Highly sensitive H2O2-scavenging nano-bionic system for precise treatment of atherosclerosis

In atherosclerosis, chronic inflammatory processes in local diseased areas may lead to the accumulation of reactive oxygen species (ROS). In this study, we devised a highly sensitive H₂O₂-scavenging nano-bionic system loaded with probucol (RPP-PU), to treat atherosclerosis more effectively. The RPP material had high sensitivity to H₂O₂, and the response sensitivity could be reduced from 40 to 10 μmol/L which was close to the lowest concentration of H₂O₂ levels of the pathological environment. RPP-PU delayed the release and prolonged the duration of PU in vivo. In Apolipoprotein E deficient (ApoE^‒/‒) mice, RPP-PU effectively eliminated pathological ROS, reduced the level of lipids and related metabolic enzymes, and significantly decreased the area of vascular plaques and fibers. Our study demonstrated that the H₂O₂-scavenging nano-bionic system could scavenge the abundant ROS in the atherosclerosis lesion, thereby reducing the oxidative stress for treating atherosclerosis and thus achieve the therapeutic goals with atherosclerosis more desirably.

Gut microbiota signature as predictors of adverse outcomes after acute ischemic stroke in patients with hyperlipidemia

Introduction

The alterations of gut microbiota have been associated with multiple diseases. However, the relationship between gut microbiota and adverse outcomes of hyperlipidemic stroke patients remains unclear. Here we determined the gut microbial signature to predict the poor outcome of acute ischemic stroke (AIS) with hyperlipidemia (POAH).

Methods

Fecal samples from hyperlipidemic stroke patients were collected, which further analyzed by 16s rRNA gene sequencing. The diversity, community composition and differential gut microbiota were evaluated. The adverse outcomes were determined by modified Rankin Scale (mRS) scores at 3 months after admission. The diagnostic performance of microbial characteristics in predicting adverse outcomes was assessed by receiver operating characteristic (ROC) curves.

Results

Our results showed that the composition and structure of gut microbiota between POAH patients and good outcome of AIS with hyperlipidemia (GOAH) patients were different. The characteristic gut microbiota of POAH patients was that the relative abundance of Enterococcaceae and Enterococcus were increased, while the relative abundance of Lachnospiraceae, Faecalibacterium, Rothia and Butyricicoccus were decreased. Moreover, the characteristic gut microbiota were correlated with many clinical parameters, such as National Institutes of Health Stroke Scale (NIHSS) score, mean arterial pressure, and history of cerebrovascular disease. Moreover, the ROC models based on the characteristic microbiota or the combination of characteristic microbiota with independent risk factors could distinguish POAH patients and GOAH patients (area under curve is 0.694 and 0.971 respectively).

Conclusions

These findings revealed the microbial characteristics of POAH, which highlighted the predictive capability of characteristic microbiota in POAH patients.

Red blood cell biomimetic nanoparticle with anti-inflammatory, anti-oxidative and hypolipidemia effect ameliorated atherosclerosis therapy

A main pathogenic factor of atherosclerosis is the local oxidative stress microenvironment. Probucol (PU) has anti-inflammatory, antioxidative and hypolipidemic effects, showing great potential to treat atherosclerosis. However, its low bioavailability limits its development. Herein, PU was encapsulated to form RP-PU with star-shaped polymers and red blood cell membranes. Star-shaped polymers show lower solution viscosity, a smaller hydrodynamic radius and a higher drug loading content than linear polymers. RP-PU had a good sustained-release effect and excellent biocompatibility. RP-PU can be efficiently internalized by cells to improve biodistribution. ApoE^-/- mice were treated with RP-PU, and the contents of lipids and related metabolic enzymes were effectively reduced. The collagen fibers in the aortic root sections were reduced by RP-PU compared with control and PU. Moreover, RP-PU inhibited foam cell formation, decreased ICAM-1 and MCP-1 expression and delayed lesion formation. Consequently, RP-PU biomimetic nanoparticles can be developed as an anti-atherosclerotic nanotherapeutic.

Association between GFAP-positive astrocytes with clinically important parameters including neurological deficits and/or infarct volume in stroke-induced animals

The effect of GFAP-positive astrocytes, as positive or negative factors on stroke complications such as infarct volume and neurological deficits is currently under debate. This review was aimed to evaluate and compare the frequency of studies that showed a positive or negative relationship between astrocyte activation with the improvement of neurological deficits and/or the decrease of infarct volume. In addition, we reviewed two possible causes of differences in results including timepoint of stroke and stroke severity. Time of GFAP assessment was considered as time point and type of stroke induction and duration of stroke as stroke severity. According to our review in the most relevant English-language studies in the PubMed, Web of Science, and Google Scholar databases from 2005 to 2020, the majority of studies (77 vs. 28) showed a negative coincidence or correlation between GFAP-positive cells with neurological improvement as well as between GFAP-positive cells with infarct volume reduction. In most reviewed studies, GFAP expression was reported as a marker related to or coinciding with worse neurological function, or greater infarct volume. However, there were also studies that showed helpful effects of GFAP-positive cells on neurological function or stroke lesion. Although there are some elucidations that the difference in these findings is due to the time point of stroke and stroke severity, our review did not confirm these interpretations.

High fat diet accelerates and exacerbates microgliosis and neuronal damage/death in the somatosensory cortex after transient forebrain ischemia in gerbils

Obesity has been known as an independent risk factor for stroke. Effects of high-fat diet (HFD)-induced obesity on neuronal damage in the somatosensory cortex of animal models of cerebral ischemia have not been studied yet. In this study, HFD-induced obesity was used to study the impact of obesity on neuronal damage/loss and microgliosis in the somatosensory cortex of a gerbil model of 5-min transient forebrain ischemia. We used gerbils fed normal diet (ND) and HFD and chronologically examined microgliosis (microglial cell activation) by ionized calcium-binding adapter molecule 1 (Iba-1) immunohistochemistry. In addition, we examined neuronal damage or death by using neuronal nuclear protein (NeuN, a neuronal marker) immunohistochemistry and Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining. We found that ischemia-induced microgliosis in ND-fed gerbils was increased from 2 days post-ischemia; however, ischemia-mediated microgliosis in HFD-fed gerbils increased from 1 day post-ischemia and more accelerated with time than that in the ND-fed gerbils. Ischemia-induced neuronal death/loss in the somatosensory cortex in the ND-fed gerbils was apparently found at 5 days post-ischemia. However, in the HFD-fed gerbils, neuronal death/loss was shown from 2 days post-ischemia and progressively exacerbated at 5 days post-ischemia. Our findings indicate that HFD can evoke earlier microgliosis and more detrimental neuronal death/loss in the somatosensory cortex after transient ischemia than ND evokes.

Effects of Solvent Stabilization on Pharmaceutical Crystallization: Investigating Conformational Polymorphism of Probucol Using Combined Solid-State Density Functional Theory, Molecular Dynamics, and Terahertz Spectroscopy

Solid-state density functional theory (DFT), molecular dynamics (MD), and terahertz (THz) spectroscopy were used to study the formation of enantiotropically related conformational Form I and Form II polymorphs of the pharmaceutical compound, probucol. DFT calculations were performed on the crystal systems to compare relative lattice energies and the solvent stabilization of the metastable Form II structure. The thermodynamics of solvent inclusion in the Form II·MeOH crystal system were determined from MD simulations, as was the favored conformation of molecular probucol in methanol and ethanol solutions. The findings from both solid-state DFT and MD calculations suggest that the preferred molecular orientations of the probucol molecule in solution and the probable inclusion of methanol in the crystal lattice during the crystallization process lead to the solvent selectivity of the probucol polymorph formation. The additional stabilization energy provided by the crystallization solvent facilitates the nucleation and growth of the Form II polymorph under conditions that favor this metastable crystal form over the thermodynamically stable Form I, despite the higher energy molecular and crystalline configurations of probucol Form II. We demonstrate the influence of solvent on the formation of pharmaceutical polymorphs and provide a molecular-level view of complex interactions leading to polymorphism using a combination of computational methods and THz spectral data.

Low molecule weight fucoidan mitigates atherosclerosis in ApoE (-/-) mouse model through activating multiple signal pathway

Atherosclerosis (AS) is a chronic inflammatory disease, and many factors are implicated in its progression. This work aims to study the preventive effects and the regulatory mechanism of low-molecular-weight fucoidan (LMWF), which is obtained from Saccharina japonica, on the development of AS. Serum biochemical indices and pathological analyses were determined via ELISA, hematoxylin and eosin (HE) and Oil Red O staining. These results indicated that LMWF ameliorated areas with atherosclerotic lesions and had a significant antioxidant effect. Anticoagulant assays showed that LMWF might serve as a potential anticoagulation drug for inhibiting the formation of atherothrombosis. Double immunofluorescence staining illustrated that LMWF inhibited both SMC proliferation and migration and macrophage formation and differentiation. A molecular biology experiment showed that LMWF exhibited an apparent regulatory effect on various signaling pathways. In conclusion, our results revealed that LMWF mitigated AS in the ApoE (-/-) mouse model by activating multiple signal pathways.

Anti-inflammatory effect of low molecular weight fucoidan from Saccharina japonica on atherosclerosis in apoE-knockout mice

Atherosclerosis (AS) is the key cause of many cardiovascular and cerebrovascular diseases. The inflammatory response and lipid metabolism disorders contribute to the development and progression of AS. This work aims to study the anti-inflammatory effect and mechanism of low molecular weight fucoidan (LMWF) obtained from Saccharina japonica on atherosclerosis in apoE-knockout mice. The experimental results showed that LMWF statistically decreased the levels of triglyceride (TRIG) and oxidative low-density lipoproteins (ox-LDL) and stabilized established atherosclerotic lesions. LMWF ameliorated the inflammatory response by down regulating IL-6 and by up regulating IL-10 transcriptional levels, and LMWF returned p-JNK and cyclin D1 to normal levels. Moreover, LMWF increased the mRNA level of CD11b in the aorta and suppressed the expression of CD11b in the intimal layer of the aorta. Therefore, LMWF prevented macrophages from developing into foam cells and prevented SMCs from migrating into the intimal layer of the aorta, which inhibited the formation of atherosclerotic plaques; and ameliorated the occurrence and development of AS.

Chronic high-fat diet-induced obesity in gerbils increases pro-inflammatory cytokines and mTOR activation, and elicits neuronal death in the striatum following brief transient ischemia

Recent studies have shown that obesity and its related metabolic dysfunction exacerbate outcomes of ischemic brain injuries in some brain areas, such as the hippocampus and cerebral cortex when they are subjected to transient ischemia. However, the impact of obesity in the striatum after brief transient ischemia has not yet been addressed. The objective of this study was to investigate effects of obesity on neuronal damage and inflammation in the striatum after transient ischemia and to examine the role of mTOR which is involved in the pathogenesis of metabolic and neurological diseases. Gerbils were fed with normal diet (ND) or high-fat diet (HFD) for 12 weeks and subjected to 5 min of transient ischemia. HFD-fed gerbils showed significant increase in body weight, blood glucose level, serum triglycerides, total cholesterol and low-density lipoprotein cholesterol without affecting food intake. Neuronal death/loss in the HFD-fed gerbils occurred in the dorsolateral striatum 2 days after transient ischemia, and neuronal loss was increased 5 days after transient ischemia, although no neuronal loss was observed in ND-fed gerbils at any time after transient ischemia. The HFD-fed gerbils showed hypertrophied microglia and further increased expressions of tumor necrosis factor-alpha, interukin-1beta, mammalian target of rapamycin (mTOR) and phosphorylated-mTOR during pre- and post-ischemic phases compared with the ND-fed gerbils. Additionally, we found that treatment with mTOR inhibitor rapamycin in the HFD-fed gerbils significantly attenuated transient ischemia-induced neuronal death in the dorsolateral striatum. These findings reveal that chronic HFD-induced obesity results in severe neuroinflammation and significant increase of mTOR activation, which could contribute to neuronal death in the stratum following 5 min of transient ischemia. Especially, abnormal mTOR activation would play a key role in mediating obesity-induced severe ischemic brain injury.

Probucol inhibits LPS-induced microglia activation and ameliorates brain ischemic injury in normal and hyperlipidemic mice

AIM

Increasing evidence suggests that probucol, a lipid-lowering agent with anti-oxidant activities, may be useful for the treatment of ischemic stroke with hyperlipidemia via reduction in cholesterol and neuroinflammation. In this study we examined whether probucol could protect against brain ischemic injury via anti-neuroinflammatory action in normal and hyperlipidemic mice.

METHODS

Primary mouse microglia and murine BV2 microglia were exposed to lipopolysaccharide (LPS) for 3 h, and the release NO, PGE2, IL-1β and IL-6, as well as the changes in NF-κB, MAPK and AP-1 signaling pathways were assessed. ApoE KO mice were fed a high-fat diet containing 0.004%, 0.02%, 0.1% (wt/wt) probucol for 10 weeks, whereas normal C57BL/6J mice received probucol (3, 10, 30 mg·kg(-1)·d(-1), po) for 4 d. Then all the mice were subjected to focal cerebral ischemia through middle cerebral artery occlusion (MCAO). The neurological deficits were scored 24 h after the surgery, and then brains were removed for measuring the cerebral infarct size and the production of pro-inflammatory mediators.

RESULTS

In LPS-treated BV2 cells and primary microglial cells, pretreatment with probucol (1, 5, 10 μmol/L) dose-dependently inhibited the release of NO, PGE2, IL-1β and IL-6, which occurred at the transcription levels. Furthermore, the inhibitory actions of probucol were associated with the downregulation of the NF-κB, MAPK and AP-1 signaling pathways. In the normal mice with MCAO, pre-administration of probucol dose-dependently decreased the infarct volume and improved neurological function. These effects were accompanied by the decreased production of pro-inflammatory mediators (iNOS, COX-2, IL-1, IL-6). In ApoE KO mice fed a high-fat diet, pre-administration of 0.1% probucol significantly reduced the infarct volume, improved the neurological deficits following MCAO, and decreased the total- and LDL-cholesterol levels.

CONCLUSION

Probucol inhibits LPS-induced microglia activation and ameliorates cerebral ischemic injury in normal and hyperlipidemic mice via its anti-neuroinflammatory actions, suggesting that probucol has potential for the treatment of patients with or at risk for ischemic stroke and hyperlipidemia.

Synergistic Effects of Cilostazol and Probucol on ER Stress-Induced Hepatic Steatosis via Heme Oxygenase-1-Dependent Activation of Mitochondrial Biogenesis

The selective type-3 phosphodiesterase inhibitor cilostazol and the antihyperlipidemic agent probucol have antioxidative, anti-inflammatory, and antiatherogenic properties. Moreover, cilostazol and probucol can regulate mitochondrial biogenesis. However, the combinatorial effect of cilostazol and probucol on mitochondrial biogenesis remains unknown. Endoplasmic reticulum (ER) stress is a well-known causative factor of nonalcoholic fatty liver disease (NAFLD) which can impair mitochondrial function in hepatocytes. Here, we investigated the synergistic effects of cilostazol and probucol on mitochondrial biogenesis and ER stress-induced hepatic steatosis. A synergistic effect of cilostazol and probucol on HO-1 and mitochondrial biogenesis gene expression was found in human hepatocellular carcinoma cells (HepG2) and murine primary hepatocytes. Furthermore, in an animal model of ER stress involving tunicamycin, combinatorial treatment with cilostazol and probucol significantly increased the expression of HO-1 and mitochondrial biogenesis-related genes and proteins, whereas it downregulated serum ALT, eIF2 phosphorylation, and CHOP expression, as well as the lipogenesis-related genes SREBP-1c and FAS. Based on these results, we conclude that cilostazol and probucol exhibit a synergistic effect on the activation of mitochondrial biogenesis via upregulation of HO-1, which confers protection against ER stress-induced hepatic steatosis.