Pitavastatin attenuates leukocyte-endothelial interactions induced by ischemia-reperfusion injury in the rat retina

Statins and the progression of age-related macular degeneration in the United States

PURPOSE

To study the effect of statin exposure on the progression from non-exudative to exudative age-related macular degeneration (AMD).

METHODS

Retrospective cohort study of commercially insured patients diagnosed with non-exudative AMD (n = 231,888) from 2007 to 2015. Time-to-event analysis of the association between exposure to lipid-lowering medications and time from non-exudative AMD to exudative AMD diagnosis was conducted. Outcome measures included progression to exudative AMD, indicated by diagnosis codes for exudative AMD or procedural codes for intravitreal injections.

RESULTS

In the year before and after first AMD diagnosis, 11,330 patients were continuously prescribed lipid-lowering medications and 31,627 patients did not take any lipid-lowering medication. Of those taking statins, 21 (1.6%) patients were on very-high-dose lipophilic statins, 644 (47.6%) on high-dose lipophilic statins, and 689 (50.9%) on low-dose lipophilic statins. We found no statistically significant relationship between exposure to low (HR 0.89, 95% CI 0.83 to 1.38) or high-dose lipophilic statins (HR 1.12, 95% CI 0.86 to 1.45) and progression to exudative AMD. No patients taking very-high-dose lipophilic statins converted from non-exudative to exudative AMD, though this difference was not statistically significant due to the subgroup size (p = .23, log-rank test).

CONCLUSIONS

No statistically significant relationship was found between statin exposure and risk of AMD progression. Interestingly, no patients taking very-high-dose lipophilic statins progressed to exudative AMD, a finding that warrants further exploration.

Improvement of endothelial function by pitavastatin: a meta-analysis

OBJECTIVE

Dyslipidemia is commonly associated with endothelial dysfunction and increased cardiovascular risk. Pitavastatin has been shown to reduce total and low-density lipoprotein cholesterol, to increase high-density lipoprotein (HDL)-cholesterol and improve HDL function. Furthermore, several trials explored its effects on flow-mediated dilation (FMD), as an index of endothelial function. The authors evaluated the effect of pitavastatin therapy on FMD.

METHODS

The authors performed a systematic review and meta-analysis of all clinical trials exploring the impact of pitavastatin on FMD. The search included PubMed-Medline, Scopus, ISI Web of Knowledge and Google Scholar databases. Quantitative data synthesis was performed using a random-effects model, with weighted mean difference (WMD) and 95% confidence interval (CI) as summary statistics.

RESULTS

Six eligible studies comprising 7 treatment arms were selected for this meta-analysis. Overall, WMD was significant for the effect of pitavastatin on FMD (2.45%, 95% CI: 1.31, 3.60, p < 0.001) and the effect size was robust in the leave-one-out sensitivity analysis.

CONCLUSION

This meta-analysis of all available clinical trials revealed a significant increase of FMD induced by pitavastatin.

Pharmacogenetic Foundations of Therapeutic Efficacy and Adverse Events of Statins

Background: In the era of precision medicine, more attention is paid to the search for predictive markers of treatment efficacy and tolerability. Statins are one of the classes of drugs that could benefit from this approach because of their wide use and their incidence of adverse events. Methods: Literature from PubMed databases and bibliography from retrieved publications have been analyzed according to terms such as statins, pharmacogenetics, epigenetics, toxicity and drug–drug interaction, among others. The search was performed until 1 October 2016 for articles published in English language. Results: Several technical and methodological approaches have been adopted, including candidate gene and next generation sequencing (NGS) analyses, the latter being more robust and reliable. Among genes identified as possible predictive factors associated with statins toxicity, cytochrome P450 isoforms, transmembrane transporters and mitochondrial enzymes are the best characterized. Finally, the solute carrier organic anion transporter family member 1B1 (SLCO1B1) transporter seems to be the best target for future studies. Moreover, drug–drug interactions need to be considered for the best approach to personalized treatment. Conclusions: Pharmacogenetics of statins includes several possible genes and their polymorphisms, but muscular toxicities seem better related to SLCO1B1 variant alleles. Their analysis in the general population of patients taking statins could improve treatment adherence and efficacy; however, the cost–efficacy ratio should be carefully evaluated.

Retinal Cell Degeneration in Animal Models

The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl₂-induced), autoimmune (experimental autoimmune encephalomyelitis), mechanical stress (optic nerve crush-induced, light-induced) and ischemia (transient retinal ischemia-induced). The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage.

Pitavastatin subacutely improves endothelial function and reduces inflammatory cytokines and chemokines in patients with hypercholesterolaemia

BACKGROUND

Pitavastatin is a statin with strong pleiotropic effects, but the effects of pitavastatin on endothelial cell function (ECF) and both inflammatory cytokines and chemokines have not been fully investigated.

MATERIAL AND METHODS

We simultaneously measured brachial artery (BA) flow-mediated vasodilatation (FMD) and nitroglycerin-mediated vasodilatation (NMD), as well as plasma biomarkers of inflammatory cytokines and chemokines, in patients with hypercholesterolaemia and other atherosclerotic risk factors who were treated with pitavastatin. Sixty-five hypercholesterolaemic patients (age, 66±11 years) with conventional coronary risk factors were enrolled. BA FMD, BA NMD and serum biomarkers (tumour necrosis factor, interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1, IL-8, P-selectin, E-selectin, soluble intercellular cell adhesion molecule-1 (s-ICAM1)) were measured before and after 4 weeks of treatment with pitavastatin (2 mg/day).

RESULTS

Pitavastatin treatment resulted in an increase from baseline to post-treatment in FMD (3.22±1.72 vs 3.97±2.18%, p<0.05) but not in NMD. Furthermore, pitavastatin treatment led to a decrease from baseline to post-treatment in E-selectin (51±27 vs 46±29 pg/mL, p<0.05) and s-ICAM1 (276±86 vs 258±91 pg/mL, p<0.05). Changes in FMD in response to pitavastatin treatment did not correlate with those of E-selectin or s-ICAM1.

CONCLUSIONS

Pitavastatin treatment resulted in a subacute improvement in ECF and a decrease in chemokine levels. These results suggest that pitavastatin might improve long-term outcomes in patients with atherosclerotic disorders.

Recent advances in cellular and molecular aspects of mammalian retinal ischemia

Retinal ischemia is a common clinical entity and, due to relatively ineffective treatment, remains a common cause of visual impairment and blindness. Generally, ischemic syndromes are initially characterized by low homeostatic responses which, with time, induce injury to the tissue due to cell loss by apoptosis. In this respect, retinal ischemia is a primary cause of neuronal death. It can be considered as a sort of final common pathway in retinal diseases and results in irreversible morphological and functional changes. This review summarizes the recent knowledge on the effects of ischemia in retinal tissue and points out experimental strategies/models performed to gain better comprehension of retinal ischemia diseases. In particular, the nature of the mechanisms leading to neuronal damage (i.e., excess of glutamate release, oxidative stress and inflammation) will be outlined as well as the potential and most intriguing retinoprotective approaches and the possible therapeutic use of naturally occurring molecules such as neuropeptides. There is a general agreement that a better understanding of the fundamental pathophysiology of retinal ischemia will lead to better management and improved clinical outcome. In this respect, to contrast this pathological state, specific pharmacological strategies need to be developed aimed at the many putative cascades generated during ischemia.

In vivo cardioprotection by pitavastatin from ischemic-reperfusion injury through suppression of IKK/NF-κB and upregulation of pAkt-e-NOS

Recent studies have uncovered the beneficial effects of statin in cardiovascular diseases; however, the role of pitavastatin in ischemia-reperfusion (IR)-induced apoptosis and myocardial damage is not established. Therefore, in this study, we aim to investigate whether pitavastatin treatment attenuates myocardial IR injury via regulating oxidative stress, inflammation, apoptosis, and phosphorylated protein kinase B (pAkt) endothelial nitric oxide synthase (e-NOS) pathways. After the 14-day treatment with pitavastatin (0.16-0.64 mg·kg·d, po) or saline, rats were subjected to 45 minutes of ischemia by occluding the left anterior descending coronary artery and to 60 minutes of reperfusion to induce myocardial damage. Pitavastatin at a dose of 0.32 and 0.64 mg/kg significantly improved cardiac function as evidenced by the normalization of the mean arterial pressure, heart rate, ±LVdP/dtmax, and left ventricular end-diastolic pressure as compared with the IR control. Additionally, pitavastatin dose-dependently normalized myocardial antioxidants, lactate dehydrogenase, and thiobarbituric acid reactive substances along with decreased serum tumor necrosis factor-α level and creatine kinase isoenzyme-MB activity. Furthermore, pitavastatin enhanced pAkt, (p) e-NOS, Bcl-2, and suppressed IκB kinase/nuclear factor-kappa B, nitrotyrosine (NO inactivation product), Bax, and capases-3 protein expression in the heart. Morphological assessments of the IR-challenged myocardium showed that 0.32 and 0.64 mg/kg of pitavastatin decrease myocardial necrosis and inflammatory changes. Thus, pitavastatin reduced IR-induced infarction and dysfunction via the augmentation of endogenous antioxidant, suppression of IκB kinase/nuclear factor-kappa B, activation of pAkt-e-NOS, and/or decreased NO inactivation and apoptosis.

Aldose reductase inhibitor fidarestat attenuates leukocyte-endothelial interactions in experimental diabetic rat retina in vivo

PURPOSE

Dysregulation of the polyol pathway has been implicated as a major cause of diabetic retinopathy. The aldose reductase inhibitor fidarestat was recently reported to prevent retinal oxidative stress and overexpression of vascular endothelial growth factor (VEGF) protein in diabetic rats. In this study, we investigated the effect of fidarestat on leukocyte-endothelial cell interactions in an in vivo experimental model for diabetic retina.

MATERIALS AND METHODS

Diabetes was induced in six-week-old male Long-Evans rats by intraperitoneal injection of streptozotocin (STZ) (75 mg/kg). The rats were divided into four experimental groups: non-diabetic control rats, untreated diabetic rats, and diabetic rats treated with a low (4 mg/kg/day) or high (16 mg/kg/day) oral dose of fidarestat. After four weeks of treatment, accumulated leukocytes in the retina were counted in vivo by acridine orange digital fluorography. Intercellular adhesion molecule-1 (ICAM-1) and VEGF-164 mRNA levels in the retina were analyzed using the quantitative reverse transcription-polymerase chain reaction. ICAM-1 protein expression in the retina was investigated by immunohistochemistry.

RESULTS

Fidarestat treatment significantly decreased concentrations of sorbitol and fructose in the retinas of STZ-induced diabetic rats. Leukocyte accumulation in the retinas of fidarestat-treated rats was significantly less than in the untreated diabetic group (P < 0.01). Fidarestat treatment significantly reduced the expression ICAM-1 mRNA, but not VEGF-164 mRNA, in the retina of diabetic rats. Immunohistochemical study also revealed the suppressive effect of fidarestat on expression of ICAM-1.

CONCLUSIONS

Oral administration of fidarestat attenuated leukocyte accumulation in the retina of STZ induced-diabetic rats, suggesting that fidarestat may have a therapeutic role in preventing the progression of diabetic retinopathy.