Statin intolerance: Now a solved problem

[Red yeast-rice-induced muscular injuries: Analysis of French pharmacovigilance database and literature review]

Red yeast rice (RYR) is a dietary supplement containing monacolins obtained by fermentation of Monascus purpureus strains. Because of its structural homology with lovastatin, monacolin K inhibits HMG-CoA reductase and shows hypocholesterolemic properties comparable to synthetic statins. We studied all cases of myopathy involving RYR reported in the French national pharmacovigilance database (6 cases) and in scientific literature (9 cases). Among these cases, 9 showed elevated creatine kinase, 3 rhabdomyolysis and 2 myalgia. Recent studies seem to show good efficacy of the RYR, however, our work reports the existence of related muscular disorders. In addition, dietary supplements currently available on the market may show considerable variability of formulation and/or the presence of contaminants. When clinicobiological disorders occur, physicians should consider the eventual use of an herbal treatment.

Statins Neuromuscular Adverse Effects

Statins are drugs widely prescribed in high-risk patients for cerebrovascular or cardiovascular diseases and are, usually, safe and well tolerated. However, these drugs sometimes may cause neuromuscular side effects that represent about two-third of all adverse events. Muscle-related adverse events include cramps, myalgia, weakness, immune-mediated necrotizing myopathy and, more rarely, rhabdomyolysis. Moreover, they may lead to peripheral neuropathy and induce or unmask a preexisting neuromuscular junction dysfunction. A clinical follow up of patients assuming statins could reveal early side effects that may cause neuromuscular damage and suggest how to better modulate their use. In fact, statin dechallenge or cessation, or the alternative use of other lipid-lowering agents, can avoid adverse events. This review summarizes the current knowledge on statin-associated neuromuscular adverse effects, diagnosis, and management. It is conceivable that the incidence of neuromuscular complications will increase because, nowadays, use of statins is even more diffused than in the past. On this purpose, it is expected that pharmacogenomic and environmental studies will help to timely predict neuromuscular complications due to statin exposure, leading to a more personalized therapeutic approach.

Hsp40s play distinct roles during the initial stages of apolipoprotein B biogenesis

Apolipoprotein B (ApoB) is the primary component of atherogenic lipoproteins, which transport serum fats and cholesterol. Therefore, elevated levels of circulating ApoB are a primary risk factor for cardiovascular disease. During ApoB biosynthesis in the liver and small intestine under nutrient-rich conditions, ApoB cotranslationally translocates into the endoplasmic reticulum (ER) and is lipidated and ultimately secreted. Under lipid-poor conditions, ApoB is targeted for ER Associated Degradation (ERAD). Although prior work identified select chaperones that regulate ApoB biogenesis, the contributions of cytoplasmic Hsp40s are undefined. To this end, we screened ApoB-expressing yeast and determined that a class A ER-associated Hsp40, Ydj1, associates with and facilitates the ERAD of ApoB. Consistent with these results, a homologous Hsp40, DNAJA1, functioned similarly in rat hepatoma cells. DNAJA1 deficient cells also secreted hyperlipidated lipoproteins, in accordance with attenuated ERAD. In contrast to the role of DNAJA1 during ERAD, DNAJB1-a class B Hsp40-helped stabilize ApoB. Depletion of DNAJA1 and DNAJB1 also led to opposing effects on ApoB ubiquitination. These data represent the first example in which different Hsp40s exhibit disparate effects during regulated protein biogenesis in the ER, and highlight distinct roles that chaperones can play on a single ERAD substrate.

The Targeting of Native Proteins to the Endoplasmic Reticulum-Associated Degradation (ERAD) Pathway: An Expanding Repertoire of Regulated Substrates

All proteins are subject to quality control processes during or soon after their synthesis, and these cellular quality control pathways play critical roles in maintaining homeostasis in the cell and in organism health. Protein quality control is particularly vital for those polypeptides that enter the endoplasmic reticulum (ER). Approximately one-quarter to one-third of all proteins synthesized in eukaryotic cells access the ER because they are destined for transport to the extracellular space, because they represent integral membrane proteins, or because they reside within one of the many compartments of the secretory pathway. However, proteins that mature inefficiently are subject to ER-associated degradation (ERAD), a multi-step pathway involving the chaperone-mediated selection, ubiquitination, and extraction (or “retrotranslocation”) of protein substrates from the ER. Ultimately, these substrates are degraded by the cytosolic proteasome. Interestingly, there is an increasing number of native enzymes and metabolite and solute transporters that are also targeted for ERAD. While some of these proteins may transiently misfold, the ERAD pathway also provides a route to rapidly and quantitatively downregulate the levels and thus the activities of a variety of proteins that mature or reside in the ER.

Uncovering the protective mechanism of Huoxue Anxin Recipe against coronary heart disease by network analysis and experimental validation

Coronary heart disease (CHD) is a leading cause of death and disability worldwide. Huoxue Anxin Recipe (HAR) is a novel Chinese Herbal Medicine formula of that has been used to treat CHD for several decades. Our previous study found that HAR had anti-oxidative effects, and could promote myocardial angiogenesis and improve cardiac function following myocardial infarction (MI) in rats. However, the active compounds, potential targets, and biological processes related to HAR have not been systematically investigated. Here, network pharmacology and experimental validation were used to study the protective mechanisms of HAR against CHD. We identified 124 active components, 124 verified targets, and 111 predictive targets. A total of 1192 genes related to CHD were identified by cDNA microarray and database analysis. A total of 47 putative targets of HAR against CHD were identified, including 32 verified targets and 15 predictive targets. ClueGo enrichment analysis identified 49 biological processes involved in the anti-CHD effects of HAR. Among them, the negative regulation of blood coagulation and regulation of collagen biosynthetic process were experimentally validated. After constructing a protein-protein interaction network and clustering with MECODE and ClusterONE, 162 key proteins (from ClueGo and clustering) were used to construct an internal interaction network. Complement C3 (C3), Fibrinogen alpha (FGA), Fibrinogen gamma (FGG), interleukin-6 (IL6), and Apolipoprotein A1 (APOA1) were the top 5 hub proteins identified by cytoHubber analysis. HAR limited the concentrations of C3, FGA, FGG, and IL6 and increased APOA1 levels. The results indicated that HAR could down-regulate blood coagulation, regulate collagen biosynthesis, inhibit peroxidation and inflammation injury, and promote cholesterol efflux. HAR could be a potential source of novel and effective drugs for CHD.

The short-term supplementation of monacolin K improves the lipid and metabolic patterns of hypertensive and hypercholesterolemic subjects at low cardiovascular risk

Background - The clinical hypocholesterolemic effect of nutraceutical compounds (NCs) containing red yeast rice extracts providing a daily dose of 2.5-10 mg of monacolin K is now well established. For this reason, NCs may be a viable alternative to the statin drugs commonly used to lower cholesterol levels. However, in order to avoid some possible statin-like side effects, most NCs available on the market contain low doses of monacolin K, which could reduce their efficacy. The aim of this study was to investigate the efficacy and safety of a NC containing high doses of monacolin K (10 mg) in improving the lipid profile and glucose metabolism when added to the diet versus the diet alone in a group of hypertensive and hyper-cholesterolemic subjects at low cardiovascular risk. Methods - Thirty subjects with grade-1 essential hypertension (mean age 51.5 ± 7.8 years, 62.9% males) were enrolled in the treatment group (NC group). These subjects followed a programmed diet and took one tablet a day of a NC containing red yeast rice, policosanols, resveratrol and chromium picolinate for 1 month and were compared with an equivalent group of subjects that followed only a diet program. Differences in serum total cholesterol (TC), low-density- and high-density-lipoprotein cholesterol (LDLC and HDLC), triglycerides (TG) and blood glucose between groups were compared by analysis of variance. Results - In both groups, a significant reduction of TC, TG and LDLC was observed. In the treatment group from the baseline to the follow-up the reduction of TC (230.93 ± 28.0 vs. 188.63 ± 18.1, p < 0.001) and LDLC (153.10 ± 22.5 vs. 116.54 ± 17.7, p < 0.001) was significantly greater compared to the control group (differences between treatments = 9.19% and 12.29%, respectively); in addition a significant higher reduction in blood glucose (89.1 ± 7.6 vs. 83.7 ± 4.6, p < 0.001) was also observed (differences between treatments = 4.28%). HDLC levels remained unchanged in both groups. Conclusions - In summary, the NC containing high doses of monacolin K appeared to be safe, well tolerated and effective at improving lipid and glucose patterns.

Can modulators of apolipoproteinB biogenesis serve as an alternate target for cholesterol-lowering drugs?

Understanding the molecular defects underlying cardiovascular disease is necessary for the development of therapeutics. The most common method to lower circulating lipids, which reduces the incidence of cardiovascular disease, is statins, but other drugs are now entering the clinic, some of which have been approved. Nevertheless, patients cannot tolerate some of these therapeutics, the drugs are costly, and/or the treatments are approved for only rare forms of disease. Efforts to find alternative treatments have focused on other factors, such as apolipoproteinB (apoB), which transports cholesterol in the blood stream. The levels of apoB are regulated by endoplasmic reticulum (ER) associated degradation as well as by a post ER degradation pathway in model systems, and we suggest that these events provide novel therapeutic targets. We discuss first how cardiovascular disease arises and how cholesterol is regulated, and then summarize the mechanisms of action of existing treatments for cardiovascular disease. We then review the apoB biosynthetic pathway, focusing on steps that might be amenable to therapeutic interventions.

Effect of Methanolic Leaf Extract of Talinum triangulare (Jacq). Willd. on Biochemical Parameters in Diet induced Dyslipidemia Wistar Rats

OBJECTIVE

To investigate the effect of methanolic leaf extract of Talinum triangulare on hematological parameters, enzymatic and non-enzymatic antioxidant status, and serum lipid in Wistar rats fed standard laboratory, or 2% cholesterol-enrich diet.

MATERIAL AND METHODS

Wistar rats (180-210g) divided into six groups of six animals (males) each were fed 2% cholesterol-enriched diet and orally treated with 0.9% saline or extract of Talinum triangulare (250, 500, and 1000 mg/kg per body weight) daily for eight weeks. Lipid profile, lipid peroxidation (MDA), hematological parameters, and their functional indices and serum antioxidant enzymes (catalase, glutathione -S-transferase, and superoxide dismutase) activities and glutathione status were assessed in normal and diet-induced hypercholesterolemic extract treated rats and compared with the rats treated with 100 mg/kg per bwt standard drug gemfibrozil.

RESULTS

A significant (P < 0.05) increase in lipid profile (total glyceride, total cholestrol, low-density lipoprotein, and very low-density lipoprotein), MDA and reduction (P < 0.05) in enzymatic and nonenzymatic antioxidant status coupled with alterations in hematological parameters was observed in the serum of hypercholesterolemic rats when compared with animals on a normal diet. Coadministration of methanolic leaf extracts of Talinum triangulare or gemfibrozil significantly (P < 0.05) restored the elevated serum lipid profile, MDA, and the deranged hematological parameters to near normal. The extract also protected against hypercholesterolemic-induced diminished enzymatic and nonenzymatic antioxidant status. The activities of the plant extract are dose (250, 500, and 1000 mg/kg) dependent and it compared favorably with the standard drug gemfibrozil.

CONCLUSION

The present study suggested that the extract of Talinum triangulare might protect against hypercholesterolemic-induced altered lipid profiles, oxidative stress, and also improve the status of antioxidant defense system and hematopoiesis.

SUMMARY

Elevated lipid profile (total glyceride, total cholestrol, low-density lipoprotein, and very low-density lipoprotein), lipid peroxidation (MDA), and reduced enzymatic and nonenzymatic antioxidant status coupled with alterations in hematological parameters was observed in the serum of hypercholesterolemic rats when compared with animals on a normal dietCoadministration of methanolic leaf extracts of Talinum triangulare significantly (P < 0.05) restored the elevated serum lipid profile, MDA, and the deranged hematological parameters to near normal.The extract also protected against hypercholesterolemic-induced diminished enzymatic and bnonenzymatic antioxidant status.The activities of the plant extract was dose-dependent and it compared favorably with the standard drug gemfibrozil. Abbreviations used: Lipid peroxidation (MDA), (catalase (CAT), glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione (GSH), Thrombocytes indices (PLT), Red blood cell (RBC), Packed cell volume (PVC), Mean corpuscular hemoglobin(MCH), Mean corpuscular hemoglobin concentration (MCHC), Total glyceride (TG), Very low density lipoprotein (VLDL), Total cholesterol (TC), Low density lipoprotein (LDL), High density lipoprotein (HDL) and 3-Hydroxy-3-methyl-glutaryl-CoA reductase(HMG-CoA).

CoQ10 and endothelial function in Asians from Korea compared to Asians born in the United States and US born Caucasians

Background

The vascular endothelium is the interface between the blood and vascular smooth muscle in arteries. It is easily damaged by oxidative stress. Recent studies show that Asians are more susceptible than Caucasians to impairment of endothelial function. This study examined endothelial function in US-born Caucasians, Asians from Korea, and US-born Asians (almost all Korean decent) and examined the effect of coenzyme Q10 (CoQ10) on endothelial function.

Material/Methods

Twenty Caucasians and 30 Asians participated (<35 years old, males and females). Endothelial function was assessed by the skin blood flow response to local heat using a thermode for 6 minutes at 44°C and by vascular occlusion for 4 minutes followed by release and measurement of skin blood flow for 2 minutes. In the US-born subjects, the experiments were repeated after 2-week administration of CoQ10 or a placebo.

Results

When applying 6 minutes of local heat at 44°C, the skin blood flows were significantly higher in Caucasians than both Asian groups Asians. Likewise after vascular occlusion, the blood flow response was greater in Caucasians compared to Asians. Asians born in Asia had the lowest response of the 3 groups of subjects. Administering CoQ10 for 2 weeks eliminated much of the difference between the groups, whereas there was no difference with a placebo.

Conclusions

These findings suggest that Asians either born in Asia or the US may have lower endothelial function than Caucasians. This may be explained, in part, by genetic variations causing increased oxidative stress from westernized diets in Asians. Co enzyme Q10 administration narrows the difference between the groups.

Peripheral neuropathy induced by red yeast rice in a patient with a known small bowel gastrointestinal tumour

Peripheral neuropathy is a well-recognised side effect of the cholesterol-lowering statins. Red yeast rice (RYR) is a traditional Chinese herb, widely available over-the-counter that has also been found to reduce cholesterol. Little data is available regarding its side effect profile. We report a case of a 60-year-old male receiving therapeutic imatinib for metastatic gastrointestinal tumour (GIST), who developed peripheral neuropathy while also taking RYR. The symptoms completely settled following withdrawal of the RYR and he has subsequently continued to take imatinib for over 2 years with no adverse effects. Further research into the safety profile of RYR is needed. The importance of questioning patients about over the counter medications and herbal remedies cannot be overemphasised.

The M2 module of the Cys-His-rich domain (CHRD) of PCSK9 protein is needed for the extracellular low-density lipoprotein receptor (LDLR) degradation pathway

PCSK9 enhances the cellular degradation of the LDL receptor (LDLR), leading to increased plasma LDL cholesterol. This multidomain protein contains a prosegment, a catalytic domain, a hinge region, and a cysteine-histidine rich domain (CHRD) composed of three tightly packed modules named M1, M2, and M3. The CHRD is required for the activity of PCSK9, but the mechanism behind this remains obscure. To define the contribution of each module to the function of PCSK9, we dissected the CHRD structure. Six PCSK9 deletants were generated by mutagenesis, corresponding to the deletion of only one (ΔM1, ΔM2, ΔM3) or two (ΔM12, ΔM13, ΔM23) modules. Transfection of HEK293 cells showed that all deletants were well processed and expressed compared with the parent PCSK9 but that only those lacking the M2 module were secreted. HepG2 cells lacking endogenous PCSK9 (HepG2/shPCSK9) were used for the functional analysis of the extracellular or intracellular activity of PCSK9 and its deletants. To analyze the ability of the deletants to enhance the LDLR degradation by the intracellular pathway, cellular expressions revealed that only the ΔM2 deletant retains a comparable total LDLR-degrading activity to full-length PCSK9. To probe the extracellular pathway, HepG2/shPCSK9 cells were incubated with conditioned media from transfected HEK293 or HepG2/shPCSK9 cells, and cell surface LDLR levels were analyzed by FACS. The results showed no activity of any secreted deletant compared with PCSK9. Thus, although M2 is dispensable for secretion, its presence is required for the extracellular activity of PCSK9 on cell surface LDLR.