The therapeutic potential of probucol and probucol analogues in neurodegenerative diseases.

Neurodegenerative disorders present complex pathologies characterized by various interconnected factors, including the aggregation of misfolded proteins, oxidative stress, neuroinflammation and compromised blood-brain barrier (BBB) integrity. Addressing such multifaceted pathways necessitates the development of multi-target therapeutic strategies. Emerging research indicates that probucol, a historic lipid-lowering medication, offers substantial potential in the realm of neurodegenerative disease prevention and treatment. Preclinical investigations have unveiled multifaceted cellular effects of probucol, showcasing its remarkable antioxidative and anti-inflammatory properties, its ability to fortify the BBB and its direct influence on neural preservation and adaptability. These diverse effects collectively translate into enhancements in both motor and cognitive functions. This review provides a comprehensive overview of recent findings highlighting the efficacy of probucol and probucol-related compounds in the context of various neurodegenerative conditions, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and cognitive impairment associated with diabetes.

Collagenase Type I and Probucol-Loaded Nanoparticles Penetrate the Extracellular Matrix to Target Hepatic Stellate Cells for Hepatic Fibrosis Therapy.

Hepatic fibrosis is a common pathological process in chronic liver diseases, characterized by excessive reactive oxygen species (ROS), activated hepatic stellate cells (HSCs), and massive synthesis of extracellular matrix (ECM), which are important factors in the development of liver cirrhosis, liver failure, and liver cancer. During the development of hepatic fibrosis, ECM collagen produced by activated HSCs significantly hinders medication delivery to targeted cells and reduces the efficiency of pharmacological therapy. In this study, we designed a multifunctional hyaluronic acid polymeric nanoparticle (HA@PRB/COL NPs) based on autophagy inhibitor probucol (PRB) and collagenase type I (COL) modification, which could enhance ECM degradation and accurately target HSCs through specificity binding CD44 receptor in hepatic fibrosis therapy. Upon encountering excessive collagen I-deposition formed barrier, HA@PRB/COL NPs performed the nanodrill-like function to effectively degrade pericellular collagen I, leading to greater ECM penetration and prominent HSCs internalization capacity of delivered PRB. In mouse hepatic fibrosis model, HA@PRB/COL NPs were efficiently delivered to HSCs through binding CD44 receptor to achieve efficient accumulation in fibrotic liver. Further, we showed that HA@PRB/COL NPs executed the optimal anti-fibrotic activity by inhibiting autophagy and activation of HSCs. In conclusion, our novel dual-functional co-delivery system with degrading fibrotic ECM collagen and targeting activated HSCs exhibits great potentials in the treatment of hepatic fibrosis in clinic. STATEMENT OF SIGNIFICANCE: The excess release of extracellular matrix (ECM) such as collagen in hepatic fibrosis hinders medication delivery and decreases the efficiency of pharmacological drugs. We aimed to develop a nano-delivery carrier system with protein hydrolyzed surfaces and further encapsulated an autophagy inhibitor (PRB) to enhance fibrosis-related ECM degradation-penetration and hepatic stellate cells (HSCs) targeting in hepatic fibrosis niche (HA@PRB/COL NPs). The COL of HA@PRB/COL NPs successfully worked as a scavenger to promote the digestion of the ECM collagen I barrier for deeper penetration into fibroid liver tissue. It also accurately targeted HSCs through specifically binding to the CD44 receptor and subsequently released PRB to inhibit autolysosome and ROS generation, thus preventing HSCs activation. Our HA@PRB/COL NPs system provided a promising therapeutic strategy for hepatic fibrosis in a clinic setting.

Probucol treatment after traumatic brain injury activates BDNF/TrkB pathway, promotes neuroregeneration and ameliorates functional deficits in mice.

BACKGROUND AND PURPOSE: Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide, yet pharmacotherapies for TBI are currently lacking. Neuroregeneration is important in brain repair and functional recovery. In this study, probucol, a cholesterol-lowering drug with established safety profiles, was examined for its therapeutic effects and neuroregenerative actions in TBI. EXPERIMENTAL APPROACH: Male mice were subjected to the controlled cortical impact model of TBI, followed by daily administration of probucol. Neurological and cognitive functions were evaluated. Histological analyses of the neocortex and hippocampus were performed to detect the lesion, dendritic degeneration (microtubule-associated protein 2), synaptic density (synaptophysin), neurogenesis (doublecortin), brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) activation. Involvement of BDNF/TrkB pathway in probucol-mediated effects was examined in primary cultures of cortical neurons. KEY RESULTS: Probucol reduced brain lesion volume, enhanced the recovery of body symmetry, improved motor function and attenuated memory dysfunction after TBI. Meanwhile, probucol promoted post-injury dendritic growth and synaptogenesis and increased hippocampal proliferating neuronal progenitor cells, along with the formation as well as the survival of newborn neurons. Moreover, probucol enhances BDNF expression and TrkB activation. In vitro, probucol promoted neurite outgrowth, which was inhibited by a selective TrkB antagonist ANA-12. CONCLUSIONS AND IMPLICATIONS: Probucol enhanced functional restoration and ameliorated cognitive impairment after TBI by promoting post-injury neuronal remodelling and neurogenesis. Increased activation of BDNF/TrkB pathway by probucol, at least in part, contributed to the neuroregenerative effects of probucol. Together, it may be promising to repurpose probucol for TBI.

Adverse drug reactions of non-statin antihyperlipidaemic drugs in China from 1989 to 2019: a national database analysis.

OBJECTIVE: This study aims to understand the adverse drug reactions (ADRs) for non-statin antihyperlipidaemic drugs included in the China Anti-hyperlipidemic Drug Database. DESIGN: An approach of Chinese national database analysis was employed to screen clinical trials involving non-statin antihyperlipidaemic drugs from 1989 to 2019. SETTING: The database was provided by the China National Medical Products Administration Information Centre. PARTICIPANTS: In total, 117 clinical studies with 8800 patients were selected from 2650 clinical trials of the Anti-hyperlipidemic Drug Database. INTERVENTIONS: The non-statin antihyperlipidaemic drugs were divided into three groups: (1) fibrates (fenofibrate, gemfibrozil, bezafibrate, etofylline clofibrate); (2) nicotinic acid and derivatives (niacin, acipimox) and (3) others (probucol, cholestyramine). RESULTS: The results of this study show that first, gastrointestinal symptoms were the most common reactions (6.975%), which account for approximately 50% of the reported cases with ADRs. Second, cholestyramine (16.418%) and gemfibrozil (13.158%) were the most common gastrointestinal side effect-causing non-statin antihyperlipidaemic drugs, which account for one-third of the population. Third, niacin (7.879%) and gemfibrozil (5.000%) were the most likely cause of liver disease symptoms. Finally, niacin (10.909%) and acipimox (18.847%) were the major non-statin antihyperlipidaemic drugs with skin symptoms. CONCLUSION: This study revealed that gastrointestinal symptoms were the most common ADRs of fibrates, probucol and cholestyramine in the Chinese population. For nicotinic acid and derivatives, the ADRs of skin symptoms were the most common in China.

Preventing contrast-induced acute kidney injury with probucol and hydration in patients with coronary heart disease: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Preventing contrast-induced acute kidney injury (CI-AKI) is critical because of its association with poor clinical outcomes, including extended hospital stays and increased mortality. The effects of probucol on preventing CI-AKI have been controversial. Therefore, this systematic review and meta-analysis evaluated the influence of probucol combined with hydration on the CI-AKI risk in patients with coronary heart disease undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI). METHODS: We retrieved data from the following databases from their inception to May 29, 2022: PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Chinese Biomedical Literature Database (Sinomed), Wanfang Database, and Chinese Scientific Journal Database. The methodological quality of the trials was assessed following the Cochrane Handbook guidelines, and Review Manager 5.3 and Stata 14.0 software were used for the data analysis. RESULTS: We included 14 trials comprising 3306 patients in the analysis. All included trials reported the CI-AKI incidence rate (the primary outcome). Probucol with hydration significantly reduced the CI-AKI incidence compared to hydration alone (odds ratio [OR]: 0.33, 95% confidence interval [CI]: 0.25-0.44, P < .001). Subgroup analyses were performed based on the contrast medium type (iso-osmolality vs low-osmolality contrast medium [LOCM]) and volume (less than or more than 200 mL); the effects of probucol with hydration versus hydration-only on CI-AKI were comparable within each subgroup. Additionally, the serum creatinine (Scr) concentration 24 hours, 48 hours, and 72 hours and the estimated glomerular filtration rate (eGFR) 72 hours after contrast exposure were better in the probucol with hydration group than the hydration-only group. Finally, major clinical adverse events and adverse drug reactions were comparable between the probucol with hydration and hydration-only groups. CONCLUSION: Probucol with hydration decreases the CI-AKI incidence compared to hydration only in patients with coronary heart disease undergoing CAG or PCI. However, more high-quality, large-sample, multicenter randomized trials are needed to confirm this conclusion.

Research and Progress of Probucol in Nonalcoholic Fatty Liver Disease.

With the development of the social economy over the last 30 years, non-alcoholic fatty liver disease (NAFLD) is affected by unhealthy living habits and eating styles and has gradually become an increasingly serious public health problem. It is very important to investigate the pathogenesis and treatment of NAFLD for the development of human health. Probucol is an antioxidant with a bis-phenol structure. Although probucol is a clinically used cholesterol-lowering and antiatherosclerosis drug, its mechanism has not been elucidated in detail. This paper reviews the chemical structure, pharmacokinetics and pharmacological research of probucol. Meanwhile, this paper reviews the mechanism of probucol in NAFLD. We also analyzed and summarized the experimental models and clinical trials of probucol in NAFLD. Although current therapeutic strategies for NAFLD are not effective, we hope that through further research on probucol, we will be able to find suitable treatments to solve this problem in the future.

Probucol suppresses osteoclastogenesis via activating Nrf2 signaling and ameliorates ovariectomy-induced bone loss.

Osteoporosis is a systemic and endocrine bone disorder distinguished by declined bone mineral density, compromised bone strength, and destruction of trabecular structure. The abnormally excessive osteoclastogenesis and bone erosion play imperative roles in the progression of osteoporosis. However, treatment of osteoporosis is far from satisfactory due to poor adherence to existing medications and adverse reactions, there is an urgent to develop novel therapies for osteoporosis. Probucol, a synthetic compound with two characteristic phenolic rings, owns anti-inflammatory and antioxidant properties. Accumulating evidence have indicated that intracellular reactive oxygen species (ROS) is closely related to osteoclastogenesis. Hence, we investigated the potential effects of probucol on osteoclastogenesis in vivo and in vitro. In this study, TRAP staining and bone slice resorption assay showed that probucol suppressed RANKL-induced osteoclast formation and function. The mRNA and protein levels of osteoclastogenesis marker genes were reduced by probucol in a concentration-dependent manner. Besides, probucol suppressed osteoclast differentiation by inhibiting ROS production, MAPKs and NF-κB signaling pathways, while Nrf2 silencing reversed the inhibitory effect of probucol on osteoclast formation and function. Consistent with the above findings, in vivo experiments demonstrated that probucol visibly alleviated bone loss caused by estrogen deficiency. In brief, these results showed the potential of anti-oxidant compound probucol in the treatment of osteoporosis, highlighting Nrf2 as a promising target in osteoclast-related disease.

Probucol promotes osteoblasts differentiation and prevents osteoporosis development through reducing oxidative stress.

Probucol (PBC) is a potent cholesterol-lowering drug and has been studied extensively for its powerful antioxidative stress. The purpose of this study is to investigate the role of PBC in ovariectomized rat model and to explore the mechanism of osteogenic differentiation of MC3TE-E1 Cells. RT-qPCR and Immunofluorescence were used to measure the expression level of SOD2, SIRT1, intracellular oxidative stress levels and osteogenic markers proteins. Moreover, CCK-8 assay was conducted to detect cell viability. Alizarin red staining and alkaline phosphatase staining were applied to examine osteogenic function and calcium deposits. The ovariectomized rat model was set up successfully and HE staining were employed to examine femoral trabeculae tissue. Our results showed that PBC suppressed MC3TE-E1 resist oxidative stress to promote osteogenic differentiation. Additionally, it was confirmed that PBC promoted osteogenic differentiation of MC3TE-E1 through inhibiting oxidative stress. Further study indicated that PBC exerted its beneficial function by suppressing oxidative stress-mediated alter bone metabolism to alleviate osteoporosis in vivo. Our research suggested that the PBC-modulated oxidative stress inhibition is responsible for activation of the process of osteogenic differentiation, providing a novel insight into the treatment of osteoporosis.

Efficacy of probucol on cognitive function in Alzheimer's disease: study protocol for a double-blind, placebo-controlled, randomised phase II trial (PIA study).

INTRODUCTION: Preclinical, clinical and epidemiological studies support the hypothesis that aberrant systemic metabolism of amyloid beta (Aß) in the peripheral circulation is causally related to the development of Alzheimer's disease (AD). Specifically, recent studies suggest that increased plasma concentrations of lipoprotein-Aß compromise the brain microvasculature, resulting in extravasation and retention of the lipoprotein-Aß moiety. The latter results in an inflammatory response and neurodegeneration ensues. Probucol, a historic cholesterol-lowering drug, has been shown in murine models to suppress lipoprotein-Aß secretion, concomitant with maintaining blood-brain-barrier function, suppressing neurovascular inflammation and supporting cognitive function. This protocol details the probucol in Alzheimer's study, a drug intervention trial investigating if probucol has potential to attenuate cognitive decline, delay brain atrophy and reduce cerebral amyloid burden in patients with mild-to-moderate AD. METHODS AND ANALYSIS: The study is a phase II, randomised, placebo-controlled, double-blind single-site clinical trial held in Perth, Australia. The target sample is 314 participants with mild-to-moderate AD. Participants will be recruited and randomised (1:1) to a 104-week intervention consisting of placebo induction for 2 weeks followed by 102 weeks of probucol (Lorelco) or placebo. The primary outcome is changed in cognitive performance determined via the Alzheimer's Disease Assessment Scales-Cognitive Subscale test between baseline and 104 weeks. Secondary outcomes measures will be the change in brain structure and function, cerebral amyloid load, quality of life, and the safety and tolerability of Lorelco, after a 104week intervention. ETHICS AND DISSEMINATION: The study has been approved by the Bellberry Limited Human Research Ethics Committee (approval number: HREC2019-11-1063; Version 4, 6 October 2021). Informed consent will be obtained from participants prior to any study procedures being performed. The investigator group will disseminate study findings through peer-reviewed publications, key conferences and local stakeholder events. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12621000726853).

Integrated Analysis of Two Probucol Trials for the Secondary Prevention of Atherosclerotic Cardiovascular Events: PROSPECTIVE and IMPACT.

AIMS: In this study, we integrated two randomized control trials, PROSPECTIVE and IMPACT, to address the effect of probucol on cerebrocardiovascular events and carotid intima-media thickness (IMT) in Japanese, Korean, and Chinese patients with coronary artery disease (CAD). METHODS: A total of 1,025 patients from the PROSPECTIVE and IMPACT studies were enrolled. The time to the first major adverse cerebrocardiovascular event, in addition to carotid IMT and lipid levels, was compared between the control and probucol groups. RESULTS: In the integrated analysis, the adjusted hazard ratio (HR) and 95% confidence interval (CI) were 0.67 and 0.44-1.03, respectively, indicating a tendency to show the effect of probucol on cerebrocardiovascular events in secondary prevention. We also found no significant differences between the control and probucol groups in the mean IMT of the carotid arteries and its changes. However, we found a significant decrease in cerebrocardiovascular events in patients with reduced levels of HDL cholesterol (HDL-C) (≥ 6.25 mg/dL) compared with those with levels ＜6.25 mg/dL (p=0.024), without any increase in adverse events such as severe ventricular arrhythmias. CONCLUSION: We demonstrated a marginal effect of probucol on cerebrocardiovascular events in Asian patients with CAD, with reasonable safety profiles. A larger study may be needed to support the effect of probucol for cardiovascular prevention.

Effectiveness and Safety of Lipid-Lowering Drug Treatments in Japanese Patients with Familial Hypercholesterolemia: Familial Hypercholesterolemia Expert Forum (FAME) Study.

AIMS: Familial hypercholesterolemia (FH) is a genetic disorder characterized by high serum levels of low-density lipoprotein (LDL)-cholesterol (LDL-C), tendon and skin xanthomas, and premature coronary artery disease (CAD). In Japan, detailed information on the current status of drug therapies for patients with FH has not been reported so far, and their efficacy and safety have not been clarified. After the introduction of ezetimibe, which can further reduce serum LDL-C levels on top of statins, the changes of management for FH patients with these drugs are of particular interest. The current study aimed to evaluate the clinical status of FH heterozygotes and homozygotes, especially focusing on the real-world lipid-lowering drug therapy, attained serum LDL-C levels, and cardiovascular events at registration and during the follow-up. METHODS: The FAME Study enrolled 762 heterozygous (including 17 newly diagnosed cases) and 7 homozygous FH patients from hospitals and clinics nationwide. Diagnosis of FH was based upon the criteria defined in the Study Report in 2008 of the Research Committee on Primary Hyperlipidemia supported by Grants-in-Aid for Scientific Research from the Japanese Ministry of Health, Labor and Welfare. Data analysis was primarily carried on heterozygous FH patients. RESULTS: Xanthoma or thickening of the Achilles tendon was observed in more than 80% of the patients. CAD was recorded in 23% of patients. Patients with parental and sibling CAD accounted for 47% and 24%, respectively. At baseline, patients without CAD who had LDL-C ＜100 mg/dL accounted for 12.3% and those with CAD who had attained the target (LDL-C ＜70 mg/dL) in the secondary prevention accounted for only 1.8%. In the multiple logistic analysis, male sex, age ＞40, heterozygous FH score ＞20, hypertension, and sibling CAD were significantly and positively associated with prevalent CAD, whereas serum HDL-cholesterol levels showed a significant inverse association with CAD. Patients treated with statin alone, statin＋ezetimibe, statin＋resin, or statin＋probucol accounted for 31.1%, 26.3%, 4.0%, and 3.7%, respectively. Patients treated with three-drug combination (statin＋ezetimibe＋resin or statin＋ezetimibe＋probucol) accounted for 7.5%. Statins and ezetimibe were used in 88.0% and 48.0% at the baseline, respectively. Although high-intensity statins were mainly prescribed, statin doses were much lower than those reported in Western countries. The addition of ezetimibe resulted in ~20% reduction in serum LDL-C. CAD was diagnosed in 17 patients with 21 episodes during follow-up. The Cox hazard model analysis demonstrated that male sex, CAD at the baseline, and parental CAD were related to the development of atherosclerotic cardiovascular disease (ASCVD) events. Furthermore, an increase in serum HDL-C was associated with a significant reduction of ASCVD events, while serum LDL-C and triglyceride levels were not related to ASCVD events. CONCLUSION: The prevalence of CAD in Japanese patients with heterozygous FH is still very high. In most of the cases, the target level of serum LDL-C was not achieved for primary and secondary prevention of CAD, suggesting that a more aggressive LDL-C lowering and appropriate management of residual risks are necessary.

Probucol attenuates NF-κB/NLRP3 signalling and augments Nrf-2 mediated antioxidant defence in nerve injury induced neuropathic pain.

Neuroinflammation is one of the most significant pathological drivers following nerve injury which along with immune cell activation, oxidative stress and other associated molecular mechanisms contribute to development of neuropathic pain characterized by hyperalgesia and allodynia. In the current study we have investigated the pharmacological effect of probucol (prb) using chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain (NP) model in rats. CCI of sciatic nerve resulted in marked decrease in pain threshold along with perturbations in anti-oxidant defence, enhanced inflammatory mediators and abnormal foot posture. Administration of prb at the doses of 8 and 16 mg/kg, p.o. for 14 days significantly attenuated the behavioural, biochemical and functional deficits following CCI of sciatic nerve. To further explore the molecular mechanisms of prb, we assessed the post treatment levels of inflammatory and oxidative stress markers like NLRP3 inflammasome, NF-κB and associated proinflammatory molecules such as IL-1 ß, TNF-α & IL-6 along with Nrf-2 and HO-1. Our findings demonstrated that CCI induced changes in levels of these markers were dose dependently reversed by administration of prb. Of note, at molecular level the elevated expression of transcription factors such as NF-κB which is crucial for Nlrp3 activation and diminished levels of Nrf-2 were manifested following CCI induction, these changes were markedly reversed with 14 days treatment of prb at both the doses. Our findings highlighted the dual pharmacological effect of prb, anti-inflammatory and anti-oxidant via modulation of NF-κB/NLRP3 signalling and Nrf-2 pathway in attenuation of CCI of sciatic nerve induced NP.

The Combination Treatment of Curcumin and Probucol Protects Chondrocytes from TNF-α Induced Inflammation by Enhancing Autophagy and Reducing Apoptosis via the PI3K-Akt-mTOR Pathway.

Osteoarthritis (OA) is a chronic joint disease characterized by cholesterol accumulation in chondrocytes, cartilage degeneration, as well as extracellular matrix (ECM) destruction, and joint dysfunction. Curcumin, a chemical that can reduce cholesterol levels in OA patients, also can inhibit the progression of OA. However, a high concentration of curcumin may also trigger apoptosis in normal chondrocytes. Besides curcumin, probucol that is found can also effectively decrease the cholesterol level in OA patients. Considering that high cholesterol is a risk factor of OA, it is speculated that the combination treatment of curcumin and probucol may be effective in the prevention of OA. To investigate the possible effects of such two chemicals on OA pathophysiology, chondrocyte apoptosis and autophagy behavior under inflammatory cytokine stress were studied, and specifically, the PI3K-Akt-mTOR signaling pathway was studied. Methods. Cell proliferation, colony formation, and EdU assay were performed to identify the cytotoxicity of curcumin and probucol on chondrocytes. Transwell assay was conducted to evaluate chondrocyte migration under TNF-α inflammation stress. Immunofluorescence, JC-1, flow cytometry, RT-PCR, and western blot were used to investigate the signal variations related to autophagy and apoptosis in chondrocytes and cartilage. A histological study was carried out on OA cartilage. Glycosaminoglycan (GAG) release was determined to evaluate the ECM degradation under stress. Results. Compared with a single intervention with curcumin or probucol, a combined treatment of these two chemicals is more effective in terms of protecting chondrocytes from stress injury induced by inflammatory cytokines. The promoted protection may be attributed to the inhibition of apoptosis and the blockage of the autophagy-related PI3K/Akt/mTOR pathway. Such results were also verified in vitro by immunofluorescence staining of OA chondrocytes and in vivo by immunohistochemistry staining of cartilage. Besides, in vivo studies also showed that when applied in combination, curcumin and probucol could block the PI3K-AKT-mTOR signaling pathway; promote COL-II expression; suppress P62, MMP-3, and MMP-13 expression; and inhibit TNF-α-stimulated cartilage degradation. Moreover, the combined medication could help reduce the release of ECM GAGs in OA cartilage and alleviate the severity of OA. Conclusion. A combined treatment of curcumin and probucol could be used to protect chondrocytes from inflammatory cytokine stress via inhibition of the autophagy-related PI3K/Akt/mTOR pathway both in vitro and in vivo, which might be of potential pharmaceutical value for OA prevention and therapy.

Abnormalities of the PRMT1-ADMA-DDAH1 metabolism axis and probucol treatment in diabetic patients and diabetic rats.

BACKGROUND: Symmetrical dimethylarginine (ADMA) endogenously inhibits nitric oxide synthase (NOS) and strongly indicates oxidant stress, whose formation primarily derived from type 1 protein arginine N-methyltransferase (PRMT1) and whose metabolism was governed by type 1 dimethylarginine dimethylaminohydrolase (DDAH1). This study aimed to evaluate participation of the PRMT1-ADMA-DDAH1 metabolism axis in the kidneys of type 2 diabetes model rats and human subjects, and the effect of probucol on this axis and renal function. METHODS: A total of 30 rats were randomly assigned to a normal group (NC, n=10), diabetic group (DM, n=10), and a diabetics under probucol treatment group (PM, n=10). Throughout 8 weeks of probucol treatment, plasma NOS, the malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO), and catalase (CAT) activity were evaluated by chemical colorimetric approach. ADMA concentration was evaluated with an enzyme-linked immunosorbent assay (ELISA) and analysis of expression of PRMT1 and DDAH1 in kidneys with reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry (IHC) and western blotting were performed. RESULTS: The expression of DDAH1 in the kidney, and the plasma NOS, NO, SOD, and CAT activities in diabetic group were lower, while MDA and the expression of PRMT1 and ADMA were higher in contrast to the control group. In diabetics rats receiving probucol, the expressions of DDAH1 and ADMA were downregulated, whereas that of PRMT1 was upregulated. Probucol inhibited the indexes of oxidative stress and improved the kidney function in both diabetic rats and humans. CONCLUSIONS: We found that the expression of the PRMT1-ADMA-DDAH1 axis was altered in the kidneys of diabetic rats. Moreover, results indicated that probucol therapy regulates expression at both ends of this axis, which may preserve renal function by reducing oxidant stress. Therefore, probucol may partially restore expression of the PRMT1-ADMA-DDAH1 axis in diabetic kidneys, immigrate oxidant stress, and enhance renal function.

Probucol improves erectile function by regulating endoplasmic reticulum stress in rats with streptozotocin-induced diabetes.

This study was to explore the effect and mechanism of Probucol on STZ-induced erectile dysfunction in diabetic rats. Thirty SD male rats aged 12 weeks were given intraperitoneal injection of STZ after fasting for 12 hr. Diabetic rats were haphazardly partitioned under two assemblies and administered 0 or 500 mg/kg probucol by oral gavage to 12 weeks. Control group was intraperitoneally injected with physiological saline, and saline was administered by oral gavage daily. Intracorporeal pressure was used to evaluate erectile function. Levels of proteins were detected using immunohistochemistry and Western blotting. α-SMA and vWF were detected using immunofluorescence staining. After treatment, erectile function in probucol group was significantly improved. Endoplasmic reticulum stress-related proteins were expressed higher in DM group than in sham group, while expression of these proteins decreased significantly in probucol group. However, α-SMA and vWF were expressed at lower levels in DM group than in sham group, and probucol treatment reversed this phenomenon. Finally, Bax and Caspase3 were expressed at higher levels and Bcl-2 was expressed at lower levels in DM group, while the opposite result was obtained in probucol group. In conclusions, probucol improves erectile function by reducing endothelial dysfunction and inhibiting PERK/ATF4/CHOP pathway in STZ-induced diabetic rats.

The role of probucol preventing contrast-induced nephropathy in patients undergoing invasive coronary procedures - Systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The aim of this meta-analysis was to synthesize the latest evidence on the effect of probucol on the incidence of contrast-induced nephropathy (CIN) in patients undergoing coronary angiography (CAG)/percutaneous coronary intervention (PCI). METHODS: A systematic literature search of PubMed, ScienceDirect, EuropePMC, ProQuest, and Clinicaltrials. gov was performed to retrieve studies that assessed probucol and CIN in CAG/PCI. RESULTS: Four studies that compared probucol with hydration alone, comprising 1270 subjects, were identified and analyzed. There was no significant difference between probucol and control groups in the baseline level of creatinine and at 48 hours; however, a significant difference was observed at 72 hours (mean difference: -3.87 µmol/L; 95% confidence interval [CI]: -6.58, -1.15; p=0.005). The meta-analysis indicated that probucol did not reduce the CIN incidence (odds ratio [OR]: 0.46; 95% CI: 0.20, 1.08; p=0.08). After performing a leave-one-out sensitivity analysis, removal of a study resulted in a lower risk of CIN (OR: 0.33; 95% CI: 0.19, 0.56; p<0.001). Probucol did not reduce the CIN incidence in a pooled adjusted effect estimate (OR: 0.75; 95% CI: 0.15, 3.87; p=0.73). There was no significant difference in the rate of major adverse events between the 2 groups (OR: 0.39; 95% CI: 0.05, 3.05; p=0.37). Funnel plot results were asymmetrical, indicating possible publication bias. Grading of Recommendations, Assessment, Development and Evaluations qualification demonstrated a low and very low certainty of evidence in unadjusted and adjusted effect estimates, respectively. CONCLUSION: Probucol did not reduce the incidence of CIN; however, due to the low certainty of evidence, further study is required for a definite conclusion. Although the p value was not significant, the confidence interval showed a nonsignificant trend toward benefit. However, this trend might have been due to publication bias.

Natural products: The role and mechanism in low-density lipoprotein oxidation and atherosclerosis.

Atherosclerosis is a chronic inflammatory, metabolic, and epigenetic disease, which leads to the life-threatening coronary artery disease. Emerging studies from bench to bedside have demonstrated the pivotal role of low-density lipoprotein (LDL) oxidation in the initiation and progression of atherosclerosis. This article hereby reviews oxidation mechanism of LDL, and the pro-atherogenic and biomarker role of oxidized LDL in atherosclerosis. We also review the pharmacological effects of several representative natural products (vitamin E, resveratrol, quercetin, probucol, tanshinone IIA, epigallocatechin gallate, and Lycopene) in protecting against LDL oxidation and atherosclerosis. Clinical and basic research supports the beneficial effects of these natural products in inhibiting LDL oxidation and preventing atherosclerosis, but the data are still controversial. This may be related to factors such as the population and the dosage and time of taking natural products involved in different studies. Understanding the mechanism of LDL oxidation and effect of oxidized LDL help researchers to find novel therapies against atherosclerosis.

Development and Clinical Application of an Enzyme-Linked Immunosorbent Assay for Oxidized High-Density Lipoprotein.

AIMS: HDL particles have various anti-atherogenic functions, whereas HDL from atherosclerotic patients was demonstrated to be dysfunctional. One possible mechanism for the formation of dysfunctional HDL is the oxidation of its components. However, oxidized HDLs (Ox-HDLs) remain to be well investigated due to lack of reliable assay systems. METHODS: We have developed a novel sandwich enzyme-linked immunosorbent assay (ELISA) for Ox-HDL by using the FOH1a/DLH3 antibody, which can specifically recognize oxidized phosphatidylcholine, a major component of HDL phospholipid (HDL-PL). We defined forced oxidation of 1 mg/L HDL-PL as 1 U/L Ox-HDL. We assessed serum Ox-HDL levels of normolipidemic healthy subjects ( n=94) and dyslipidemic patients (n=177). RESULTS: The coefficients of variation of within-run and between-run assays were 12.5% and 13.5%. In healthy subjects, serum Ox-HDL levels were 28.5±5.0 (mean±SD) U/L. As Ox-HDL levels were moderately correlated with HDL-PL (r=0.59), we also evaluated the Ox-HDL/HDL-PL ratio, which represents the proportion of oxidized phospholipids in HDL particles. In dyslipidemic patients, Ox-HDL levels were highly variable and ranged from 7.2 to 62.1U/L, and were extremely high (50.4±13.3U/L) especially in patients with hyperalphalipoproteinemia due to cholesteryl ester transfer protein deficiency. Regarding patients with familial hypercholesterolemia, those treated with probucol, which is a potent anti-oxidative and anti-hyperlipidemic drug, showed significantly lower Ox-HDL (16.2±5.8 vs. 30.2±5.4, p＜0.001) and Ox-HDL/HDL-PL ratios (0.200±0.035 vs. 0.229±0.031, p=0.015) than those without probucol. CONCLUSION: We have established a novel sandwich ELISA for Ox-HDL, which might be a useful and easy strategy to evaluate HDL functionality, although the comparison study between this Ox-HDL ELISA and the assay of HDL cholesterol efflux capacity remains to be done. Our results indicated that probucol treatment may be associated with lower Ox-HDL levels.