Fluvastatin attenuates IGF-1-induced ERK1/2 activation and cell proliferation by mevalonic acid depletion in human mesangial cells

Effect of Lipid-Lowering Drugs on Renal and Cardiovascular Outcomes in Patients with Chronic Kidney Disease and Dyslipidemia: A Retrospective Cohort Study

The effects of lipid-lowering drugs (LLDs) on cardiovascular and renal outcomes in patients with advanced chronic kidney disease (CKD) and dyslipidemia are not completely understood. We conducted a retrospective cohort study to evaluate the effect of LLDs on end-stage kidney disease (ESKD), major adverse cardiovascular events (MACEs), and mortality in adult patients with CKD stage 3b, 4, or 5, and dyslipidemia. Participants were recruited between January 1, 2008, and December 31, 2018, and classified as LLD or non-LLD users; the final follow-up date was December 31, 2020. The primary outcome was time to ESKD or death due to renal failure. Sub-distribution hazard regression models adjusted for multivariables, including time-varying lipid profile covariates, were used for the analysis. Among the 6,740 participants, 4,280 patients with CKD and dyslipidemia, including 872 using LLDs and 3,408 not using LLDs, completed the primary analysis. The multivariable analyses showed that LLD users had a significantly lower risk of time to the composite renal outcome (adjusted hazard ratio [aHR], 0.76, 95% confidence interval [CI], 0.65-0.89), and MACE incidence (aHR, 0.75, 95% CI, 0.62-0.93) than did non-LLD users. After adjusting for time-varying covariates of the lipid profile, there was a significant difference in the composite renal outcome (aHR, 0.78, 95% CI, 0.65-0.93) and MACEs (aHR, 0.77, 95% CI, 0.60-0.98). Among adult patients with advanced CKD and dyslipidemia, LLD users had a significantly lower risk of composite renal outcomes and MACEs than non-LLD users. In addition to reducing lipid profile, the use of LLD is associated with renal and cardiovascular protective effects.

Dissecting Efficacy and Metabolic Characteristic Mechanism of Taxifolin on Renal Fibrosis by Multivariate Approach and Ultra-Performance Liquid Chromatography Coupled With Mass Spectrometry-Based Metabolomics Strategy

Taxifolin (TFN) is an important natural compound with antifibrotic activity; however, its pharmacological mechanism is not clear. In this study, our aim is to gain insight into the effects of TFN and its potential mechanisms in unilateral ureteral obstruction (UUO) animal model using metabolomics approach to identify the metabolic biomarkers and perturbed pathways. Serum metabolomics analysis by UPLC-Q-TOF/MS was carried out to discover the changes in the metabolic profile. It showed that TFN has a significant protective effect on UUO-induced renal fibrosis and a total of 32 potential biomarkers were identified and related to RF progression. Of note, 27 biomarkers were regulated by TFN treatment, which participate in eight metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, and phenylalanine metabolism. It also showed that metabolomics was a promising strategy to better dissect metabolic characteristics and pharmacological mechanisms of natural compounds by multivariate approach and ultra-performance liquid chromatography coupled with mass spectrometry.

Effects of atorvastatin on renal function in patients with dyslipidemia and chronic kidney disease: assessment of clinical usefulness in CKD patients with atorvastatin (ASUCA) trial

Background

Dyslipidemia is a risk factor for the progression of chronic kidney disease (CKD). While conventional lipid lowering therapy provides a benefit to CKD management, the effect of statins on eGFR remains unclear.

Methods

A prospective, multi-center, open-labeled, randomized trial. Total of 349 CKD patients with hyperlipidemia were randomized into 2 groups, and followed for 2 years. Group A included patients who were treated with atorvastatin. Group C were treated with conventional lipid lowering drugs other than statin. Primary endpoint was changes in eGFR. Secondary endpoints included changes in urinary albumin excretion, serum LDL-C, serum triglyceride, cardio-vascular events and all-cause mortality.

Results

As the primary endpoint, eGFR decreased by 2.3 ml/min/1.73 m² in Group A and by 2.6 ml/min/1.73 m² in Group C, indicating that there was no difference in change of eGFR between the two groups. As secondary endpoints, atorvastatin succeeded to reduce serum LDL-C level significantly and rapidly, but conventional therapy did not. In fact, mean LDL-C level did not reach the target level of 100 mg/dl in Group C. Serum triglyceride was lowered only by atorvastatin, but not conventional drugs. The number of cardiovascular events and all-cause mortality did not differ between in two groups.

Conclusion

The ASUCA (Assessment of Clinical Usefulness in CKD Patients with Atorvastatin) trial demonstrated that atorvastatin failed to exhibit reno-protections compared to conventional therapy in Japanese patients with dyslipidemia and CKD. It would be due in part to the ability of atorvastatin to more potently reduce serum LDL and triglycerides compared to conventional therapy.

Statin induces apoptosis of human colon cancer cells and downregulation of insulin-like growth factor 1 receptor via proapoptotic ERK activation

Insulin-like growth factor 1 (IGF-1) and IGF-1 receptor (IGF-1R) signaling plays an important role in tumor progression in patients with certain gastrointestinal tract cancers. In addition to lowering cholesterol in serum, statins have pleiotropic effects, including anti-oxidative, anti-inflammatory or anti-neoplastic effects. Therefore, the present study investigated whether statins could induce the apoptosis of colon cancer cells and regulate the expression of IGF-1R and its associated signaling pathways in the present study. It was demonstrated that simvastatin and pravastatin suppressed cell proliferation and induced cell death in human HT-29 cells, but simvastatin was more potent than pravastatin. Simvastatin induced apoptosis in a concentration-dependent manner. In addition, simvastatin suppressed the expression of IGF-1R and inhibited the activity of phosphorylated-extracellular signal-regulated kinase (ERK)1/2 and phosphorylated-Akt activated by IGF-1. Simvastatin and IGF-1 each stimulated the activity of phosphorylated ERK1/2. However, simvastatin inhibited cell proliferation and IGF-1 stimulated cell proliferation. Mevalonic acid and PD98059 reversed the ERK activation and apoptosis induced by treatment with simvastatin. It was concluded that simvastatin induces the apoptosis of human colon cancer cells and inhibits IGF-1-induced ERK and Akt expression via the downregulation of IGF-1R expression and proapoptotic ERK activation. Simvastatin may be beneficial for the treatment of colon cancer. The present study suggested that statin may possess therapeutic potential for the treatment of colon cancer.

Statins Modulate Cyclooxygenase-2 and Microsomal Prostaglandin E Synthase-1 in Human Hepatic Myofibroblasts

Statins have been shown to exert anti-inflammatory and anti-fibrogenic properties in the liver. In the present study, we explored the mechanisms underlying anti-fibrogenic effects of statins in isolated hepatic myofibroblasts and focused on cyclooxyegnase-2, a major anti-proliferative pathway in these cells. We show that simvastatin and fluvastatin inhibit thymidine incorporation in hMF in a dose-dependent manner. Pretreatment of cells with NS398, a COX-2 inhibitor, partially blunted this effect. cAMP levels, essential to the inhibition of hMF proliferation, were increased by statins and inhibited by non-steroidal anti-inflammatory drugs. Since statins modify prenylation of some important proteins in gene expression, we investigated the targets involved using selective inhibitors of prenyltransferases. Inhibition of geranylgeranylation resulted in the induction of COX-2 and mPGES-1. Using gel retardation assays, we further demonstrated that statins potentially activated the NFκB and CRE/E-box binding for COX-2 promoter and the binding of GC-rich regions and GATA for mPGES-1. Together these data demonstrate that statin limit hepatic myofibroblasts proliferation via a COX-2 and mPGES-1 dependent pathway. These data suggest that statin-dependent increase of prostaglandin in hMF contributes to its anti-fibrogenic effect.

Epirubicin inhibits growth and alters the malignant phenotype of the U‑87 glioma cell line

Epirubicin, an anthracycline derivative, is one of the main line treatments for brain tumors. The aim of the present study was to verify that epirubicin alters the growth and morphological characteristics of U‑87 glioma cells. In the present study, the effects of epirubicin were tested using cellular and biochemical assays, which demonstrated its anti‑proliferative and cytotoxic effects, with an IC50 of 6.3 µM for the U‑87 cell line, while rat normal neuronal cells were resistant to epirubicin. Epirubicin also reduced the secretion of matrix metalloproteinase‑9 by 48 and 56% at concentrations of 2.5 and 5 µM, respectively. Exposure to epirubicin also diminished levels of vascular endothelial growth factor in U‑87 cells. Furthermore, a cell migration assay showed a significant decrease in cell migration from 28 to 59% following exposure to 1 µM epirubicin. The present study demonstrated the cytotoxic, anti‑proliferative and anti‑migrative potential of epirubicin against glioma cells in vitro.

Change of MAX interactor 1 expression in an anti-Thy1 nephritis model and its effect on mesangial cell proliferation

BACKGROUND/AIMS

During the disease process of mesangial proliferative glomerulonephritis, the expression of various factors that influence mesangial proliferation is altered. MAX interactor 1 (Mxi1) antagonizes the transcription factor Myc and is believed to be a tumor suppressor. However, no studies have investigated its effect on mesangial cell proliferation.

METHODS

To investigate the effect of Mxi1 on renal mesangial cell proliferation, we established a classic rat anti-Thy1 mesangial proliferative glomerulonephritis model. Mesangial proliferation was estimated by immunohistochemical analysis of Ki67. Mxi1 expression at each time point was assessed by real-time RT-PCR and Western blot analyses. Furthermore, we altered the expression level of Mxi1 by a plasmid and siRNA to detect its effect on rat mesangial cell proliferation in vitro.

RESULTS

Mxi1 expression decreased significantly during the proliferative period of anti-Thy1 nephritis model and then gradually increased as proliferation declined, indicating that Mxi1 may be linked to mesangial cell proliferation. Upregulation of Mxi1 expression via plasmid transfection in vitro reduced the expression of the positive-acting cell cycle regulatory proteins cyclin B1, cyclin D1, cyclin E, CDC2 and CDK2; significantly reduced mesangial cell proliferation; reduced the percentage of S phase cells; and increased the percentage of G2/M phase cells. Inhibition of Mxi1 expression by siRNA in vitro produced the opposite effects: increased expression of cyclin B1, cyclin D1, cyclin E, CDC2 and CDK2; markedly increased cell proliferation; higher percentage of S phase cells; and dramatically lower percentage of G2/M phase cells. Transcription factor c-myc protein expression showed no obvious difference after Mxi1 plasmid and siRNA transfection. The expressions of cell cycle regulatory proteins mentioned above were negative correlated with Mxi1 expression in anti-Thy1 nephritis model.

CONCLUSION

These results suggest that Mxi1 expression levels were inversely correlated with proliferation in anti-Thy1 nephritis rats and it may influence cell cycle progression and thus the rate of mesangial cell proliferation by regulating the expression of c-myc target cell cycle regulatory proteins.

Effect of simvastatin on cholesterol metabolism in C2C12 myotubes and HepG2 cells, and consequences for statin-induced myopathy

The mechanism of statin-induced skeletal muscle myopathy is poorly understood. We investigated how simvastatin affects cholesterol metabolism, ubiquinone levels, and the prenylation and N-linked glycosylation of proteins in C2C12 myotubes. We used liver HepG2 cells for comparison, as their responses to statins are well-characterized in terms of their cholesterol metabolism (in contrast to muscle cells), and statins are well-tolerated in the liver. Differences between the two cell lines could indicate the mechanism behind statin-induced myopathy. Simvastatin reduced de novo cholesterol production in C2C12 myotubes by 95% after 18h treatment. The reduction was 82% in the HepG2 cells. Total cholesterol pools, however, remained constant in both cell lines. Simvastatin treatment similarly did not affect total ubiquinone levels in the myotubes, unlike in HepG2 cells (22% reduction in CoQ10). Statin treatment reduced levels of Ras and Rap1 prenylation in both cell lines, whereas N-linked glycosylation was only affected in C2C12 myotubes (21% reduction in rate). From these observations, we conclude that total cholesterol and ubiquinone levels are unlikely to be involved in statin-mediated myopathy, but reductions in protein prenylation and especially N-linked glycosylation may play a role. This first comparison of the responses to simvastatin between liver and skeletal muscle cell lines may be important for future research directions concerning statin-induced myopathy.