Treatment with atorvastatin attenuates progression of insulin resistance and pancreatic fibrosis in the Otsuka Long-Evans Tokushima fatty rats

Effects of atorvastatin on the function of Tenon's capsule fibroblasts in human eyes

PURPOSE

This study aimed to explore the role of atorvastatin (ATO) in the prevention and treatment of the scarring of filtration channels after glaucoma surgery.

METHODS

Human Tenon's capsule fibroblasts (HTFs) were co-cultured with various concentrations of ATO. First, Cell Counting Kit-8 assay was performed to evaluate the effects of various concentrations of ATO on the viability of HTFs. Then, after the ATO stimulated the HTFs for 24 h, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to evaluate the apoptosis of HTFs. Transwell assay was also performed to evaluate the migration of HTFs. Moreover, enzyme-linked immunosorbent assay (ELISA) was performed to detect the protein expression levels of transforming growth factor-β1 (TGF-β1) and TGF-β2 in the cell culture supernatant of HTFs. Western blot was carried out to detect the protein expression levels of smooth muscle actin (SMA), p38, Smad3, fibronectin, collagen I and collagen III in different groups.

RESULTS

The results revealed that ATO could inhibit the proliferation and migration of HTFs. Based on the TUNEL assay, 100 μM and 150 μM ATO could induce cell apoptosis. The ELISA results indicated that ATO could down-regulate the expression level of TGF-β2, and western blot analysis revealed that the protein expression levels of SMA, p38, Smad3, fibronectin, collagen I and collagen III in the TGF-β2 group were all up-regulated compared with the control group, whereas the addition of ATO could reverse this up-regulation.

CONCLUSIONS

ATO could inhibit the proliferation and migration of HTFs and induce their apoptosis. It was preliminary proven that ATO could inhibit the signaling pathway induced by TGF-β. It is suggested that ATO could be a basis for the treatment of the scarring of filtration channels after glaucoma surgery.

Efficacy of oral rosuvastatin intervention on HDL and its associated proteins in men with type 2 diabetes mellitus

PURPOSE

High-density lipoprotein (HDL) undergoes structural and functional modification in patients with type 2 diabetes mellitus (T2DM). There are limited data on effect of rosuvastatin on HDL-associated proteins and the antiatherogenic effects of rosuvastatin. The present study intended to study the efficacy of rosuvastatin intervention on HDL-associated proteins and its other antiatherogenic effects in men with T2DM.

METHODS

Men with T2DM on oral antidiabetic treatment, with LDL-C levels > 75 mg/dL and willing for rosuvastatin intervention (20 mg/day orally for a period of 12 weeks), were included. Fasting glucose, lipid profile were measured using standard methods. Oxidized low-density lipoprotein (oxLDL), oxidized HDL (oxHDL), paraoxonase-1 (PON-1), tumour necrosis factor-α (TNF-α) and lecithin:cholesterol acyltransferase (LCAT) in serum were measured by ELISA; serum myeloperoxidase (MPO) by spectrophotometric method and cholesterol efflux by fluorometric assay. Carotid intima-media thickness (cIMT) measurement to assess vascular health status was done using doppler.

RESULTS

Rosuvastatin produced a significant decrease (p < 0.05) in lipids (total cholesterol, triglycerides, LDL-C); oxidative stress (oxLDL, oxHDL, MPO); inflammation (TNF-α); LCAT concentration; cIMT; significant increase in antiatherogenic HDL and cholesterol efflux (p < 0.05) and no change in apoA-I levels from baseline to 12 weeks of follow-up. A decrease in MPO activity was found to be independently associated with an increase in cholesterol efflux.

CONCLUSIONS

Post intervention there is a quantitative and qualitative improvement in HDL, which helps in its reverse cholesterol transport (RCT) and antioxidant functions. Improvement in HDL functions and suppression of inflammation by rosuvastatin lead to regression in cIMT, which is beneficial in decreasing the progression of cardiovascular disease (CVD) in men with diabetes.

Atorvastatin attenuates obese-induced kidney injury and impaired renal organic anion transporter 3 function through inhibition of oxidative stress and inflammation

An excessive consumption of high-fat diet can lead to the alterations of glucose and lipid metabolism, impaired insulin signaling and increased ectopic lipid accumulation resulting in renal lipotoxicity and subsequent renal dysfunction. Atorvastatin is a lipid-lowering drug in clinical treatment. Several studies have reported that atorvastatin has several significant pleiotropic effects including anti-inflammatory, antioxidant, and anti-apoptotic effects. However, the effects of atorvastatin on metabolic disturbance and renal lipotoxicity in obesity are not fully understood. In this study, obesity in rat was developed by high-fat diet (HFD) feeding for 16 weeks. After that, the HFD-fed rats were received either a vehicle (HF), atorvastatin (HFA) or vildagliptin (HFVIL), by oral gavage for 4 weeks. We found that HF rats showed insulin resistance, visceral fat expansion and renal lipid accumulation. Impaired renal function and renal organic anion transporter 3 (Oat3) function and expression were also observed in HF rats. The marked increases in MDA level, renal injury and NF-κB, TGF-β, NOX-4, PKC-α expression were demonstrated in HF rats. Atorvastatin or vildagliptin treatment attenuated insulin resistance and renal lipid accumulation-induced lipotoxicity in HFA and HFVIL rats. Moreover, the proteins involved in renal inflammation, fibrosis, oxidative stress and apoptosis were attenuated leading to improved renal Oat3 function and renal function in the treated groups. Interestingly, atorvastatin showed higher efficacy than vildagliptin in improving insulin resistance, renal lipid accumulation and in exerting renoprotective effects in obesity-induced renal injury and impaired renal Oat3 function.

Salsalate Prevents β-Cell Dedifferentiation in OLETF Rats with Type 2 Diabetes through Notch1 Pathway

A strategic approach is urgently needed to curb the growing global epidemic of diabetes. In this study, we investigated the effects and mechanisms of salsalate (SAL), an anti-inflammatory drug with anti-diabetic properties, assessing its potential to prevent diabetes in Otsuka Long-Evans Tokushima Fatty rats (OLETF). All animals in our placebo group developed diabetes, whereas none in the SAL test group did so, and only 25% of SAL-treated rats displayed impaired glucose tolerance (IGT). SAL lowered levels of glucagon and raised levels of insulin in plasma, while improving both insulin sensitivity and β-cell function. The protective effect of SAL is likely due to diminished β-cell dedifferentiation, manifested as relative declines in Neurogenin 3⁺/insulin^- cells and synaptophysin⁺/islet hormone^- cells and increased expression of β-cell-specific transcription factor Foxo1. Both Notch1-siRNA and N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT; an indirect inhibitor of the Notch1 pathway) were shown to prevent β-cell dedifferentiation. Similar to DAPT, SAL effectively reduced β-cell dedifferentiation, significantly suppressing Notch1 pathway activation in INS-1 cells. The inhibitory role of SAL in β-cell dedifferentiation may thus be attributable to Notch1 pathway suppression.

Gymnemic acid alleviates inflammation and insulin resistance via PPARδ- and NFκB-mediated pathways in db/db mice

GA ameliorates obesity-induced inflammation and IR via PPARδ- and NFκB-mediated signaling in the liver, skeletal muscle and adipose tissue of db/db mice.