Statins induce beneficial vascular effects. How statins induce beneficial vascular effects is yet to be determined. Here we examine Simvastatin and vascular endothelial growth factor (VEGF) acting through the phosphoinositide 3-kinase (PI3K) pathway in human coronary artery endothelial cells (HCAEC). While Simvastatin and VEGF both activated mediators in the PI3K pathway, the proteins and the rates of activation were not always consistent. This suggests that although Simvastatin and VEGF share a common PI3K pathway in HCAEC and similar vascular effects, the agonists diverge in the induction of cellular signaling cascades. Simvastatin also was shown to induce phosphoinositide 3, 4, 5-triphosphate (PIPS) organization and PI3K p110 gamma (y) perinuclear localization. Beneficial, non-lipid lowering effects of statins may occur through the PI3K pathway through activation of distinct mediators from those of VEGF. Better understanding of the pathways associated with statins is necessary for the discovery of better treatments for cardiovascular disease (CVD). / Department of Biology

Statins are widely used to treat hypercholesterolemia. Statins inhibit cholesterol biosynthesis, thereby activating genes involved in cholesterol homeostasis, which are under the control of the Sterol Regulatory Element (SRE). Statins also have cholesterol-independent beneficial cardiovascular effects mediated through the phosphoinositide 3-kinase (PI3-K) / Akt signaling pathway and by inhibition of protein prenylation. Because statins inhibit the synthesis of isoprenoids, they can act by inhibiting the small signaling GTPases Ras and Rho, which require post-translational prenylation to become membrane-anchored and functional. We showed that simvastatin-mediated inhibition of protein prenylation does not appear to play a role in activation of SRE transcriptional activity in HepG2 cells. We also found that when isoprenoids were replenished, basal phospho-Akt decreased, suggesting that inhibition of prenylation by simvastatin mediates Akt phosphorylation. Future studies will be needed to investigate the role that inhibition of protein prenylation plays in the activation of the PI3-K/Akt pathway by simvastatin. / Department of Biology

Staphylococcus aureus is a common and versatile opportunistic pathogen in humans. Increases in the incidence of community acquired and nosocomial infections, coupled with the emergence of antibiotic resistant strains, are causing new treatment challenges for health care professionals. S. aureus readily binds to the endothelial cell surface and utilizes host cell endocytosis to evade host cell immune responses. Inhibition of endocytosis may cause S. aureus to remain unprotected at the host cell surface, allowing host immune systems and other therapeutics more time to clear an infection. Simvastatin inhibits host cell endocytosis. We hypothesize that using simvastatin to inhibit S. aureus invasion of host cells, a high throughput, small molecule screen can be developed. The high throughput screen will evaluate the National Institutes of Health small molecule library for compounds that better inhibit endocytosis. Additionally, 2-dimensional gel electrophoresis will be performed to elucidate the pathway simvastatin alters to inhibit endocytosis. / Department of Biology

Sepsis is a systemic inflammatory response that causes, increased heart rate, respirations, fever, and inadequate blood flow to organs. One of the most prevalent causes of sepsis is Staphylococcus aureus (S. aureus). With increasing numbers of strains of bacteria becoming antibiotic resistant, new methods for the treatment and clearance of sepsis are needed. Studies have shown that the lipid lowering drug simvastatin is protective for incidence of sepsis, having immunomodulatory effects and anti-inflammatory properties, specifically. Thus, it may be an alternative way to prevent sepsis due to S. aureus infections. Studies in our laboratory have shown that simvastatin pretreatment increases survival of mice infected with S. aureus and alters the adaptive immune response such that levels of IgG2c are reduced to the level of uninfected controls. Our studies have demonstrated that while simvastatin does not enhance bacterial clearance, or affect serum C5a levels, it does decrease serum levels of TNF. / Department of Biology

Access to abstract restricted until May 2016. / Access to thesis restricted until May 2016 / Department of Biology

[Truncated abstract] The metabolic syndrome is characterized by cardiovascular risk factors including dyslipidemia, insulin resistance, visceral obesity, hypertension and diabetes. The dyslipidemia of the metabolic syndrome includes elevated plasma triglyceride and apolipoprotein (apo) B levels, accumulation of small, dense low-density lipoprotein (LDL) particles and low high-density lipoprotein (HDL) cholesterol concentration. However, the precise mechanisms for this dyslipoproteinemia, specifically low plasma HDL cholesterol, are not well understood. This thesis therefore, focuses on HDL, its structure, function and metabolism. However, lipoprotein metabolism is a complex interconnected system, which includes forward and reverse cholesterol transport pathways. Hence, this thesis also examines and discusses the metabolism of apoB-containing lipoproteins. This thesis tests the general hypothesis that apolipoprotein kinetics are altered in the metabolic syndrome, and that lipid regulating therapies can improve these kinetic abnormalities. The aims were first, to compare and establish the clinical, metabolic and kinetic differences between metabolic syndrome and lean subjects; and second, to determine the regulatory effects of statin therapy, specifically, rosuvastatin on lipoprotein transport in the metabolic syndrome. Five observation statements were derived from the general hypothesis and examined in the studies described below. The findings are presented separately as a series of original publications. Study 1 Twelve men with the metabolic syndrome and ten lean men were studied in a case-control setting. ... These findings explain the HDL raising effects of rosuvastatin in the metabolic syndrome. Collectively, these studies suggest that the dyslipidemia of the metabolic syndrome results from increased production rates of VLDL and LDL particles, reduced fractional catabolic rates of these lipoproteins, together with accelerated catabolism of HDL particles. Treatment with rosuvastatin increases the catabolic rates of all apoB-containing lipoproteins and at a higher dose, decreases LDL apoB production. These effects are consistent with inhibition of cholesterol synthesis leading to an upregulation of LDL receptors. Rosuvastatin decreases the fractional catabolism of HDL particles. The effects of rosuvastatin on HDL kinetics may be related to a reduction in triglyceride concentration and cholesterol ester transfer protein activity. These findings are consistent with the general hypothesis that apolipoprotein kinetics are altered in the metabolic syndrome, and that statin therapy improves these kinetic abnormalities.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (MNutrition (ITE))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Background Statins are drugs of known efficacy in the treatment of hypercholesterolaemia. However, statin-induced myopathy, an adverse effect of statins in up to 15% of its users, has warranted a reduction in the prescription dose or discontinuation of the drug. The exact mechanism of statin-induced myopathy is unknown, but the potential of Coenzyme Q10 (CoQ10) as treatment has been recognized due to decreased human plasma CoQ10 levels found after statin use and the concomitant role of CoQ10 in muscle function. Objectives This systematic review assessed the effect of CoQ10 supplementation on: the severity of statin-induced myopathic symptoms, levels of plasma creatine kinase, intramuscular and plasma CoQ10, as well as whether any adverse effects of CoQ10 supplementation such as abdominal pain, nausea and vomiting or headaches were experienced. Search methods Two searches for studies were conducted in The Cochrane Central Register of Controlled Trials (inception to March 2011 and inception to November 2011), MEDLINE (inception to March 2011 and inception to November 2011), Web of Science (inception to March 2011 and inception to November 2011), Science Direct (inception to March 2011 and inception to February 2012), Wiley Online Library (inception to March 2011 and inception to February 2012), Springerlink (inception to April 2011 and inception to February 2012), EBSCOhost [Academic Search Premier and CAB abstracts (inception to March 2011 and inception to February 2012), CINAHL (inception to March 2011 and inception to November 2011)], Scopus (inception to March 2011 and inception to November 2011) and Google Scholar (inception to March 2011 and inception to February 2012). Reference lists of articles were hand searched for relevant clinical trials. Only trials with a full text were included in the review. Selection criteria Randomised controlled trials (RCTs) were included with adult participants (mean of 18-64.99 years) of all race/ethnic groups and gender on statin therapy with reported myopathic symptoms from an unknown cause. The intervention was in the form of a pure oral supplement of CoQ10 irrespective of dose, duration and frequency, and the control in the form of a placebo, a similar antioxidant, or no intervention. Outcomes included the severity of myopathic symptoms, levels of plasma creatine kinase (U/L), intramuscular CoQ10 (μmol/kg) and plasma CoQ10 (μmol/L), as well as adverse effects of CoQ10. Data collection and analysis The principle investigator and one independent reviewer selected the studies, extracted data and assessed for risk of bias using the Cochrane Collaboration‘s tool for assessing risk of bias. Authors of relevant clinical trials were contacted for additional information. Results Two RCTs were included in the review, totaling 76 participants. A meta-analysis could not be performed, thus the review is narrative. There were an insufficient number of RCTs to confirm whether routine supplementation of CoQ10 improves statin-induced myopathic symptoms. Conclusions More and larger RCTs are required to determine the efficacy of CoQ10 supplementation in statin-induced myopathy. Consensus needs to be reached regarding the definition and measurement instrument/s of myopathy so that results of future studies can easily be compared and synthesized. / AFRIKAANSE OPSOMMING: Agtergrond Statiene is medikasie bekend vir die effektiewe behandeling van hipercholesterolemie. Statien-geïnduseerde miopatie is egter 'n newe-effek wat voorkom in tot 15% van gebruikers, wat 'n vermindering in die voorgeskrewe dosis of staking van die medikasie tot gevolg het. Die presiese meganisme van statien-geïnduseerde miopatie is onbekend, maar die potensiaal van Koënsiem Q10 (CoQ10) is geïdentifiseer as 'n moontlike behandeling aangesien menslike plasma CoQ10 vlakke verlaag na die gebruik van statiene en as gevolg van die rol van CoQ10 in spierfunksie. Doelwitte Hierdie sistematiese literatuuroorsig het die effek van CoQ10 supplementasie bepaal op: die graad van statien-geïnduseerde miopatiese simptome, plasma kreatien kinase vlakke, intra-muskulêre en plasma CoQ10 vlakke, asook die teenwoordigheid van enige newe-effekte van CoQ10 supplementasie soos abdominale pyn, naarheid en braking of hoofpyne. Soektogstrategie Twee soektogte vir studies is uitgevoer in The Cochrane Central Register of Controlled Trials (ontstaan tot Maart 2011 en ontstaan tot November 2011), MEDLINE (ontstaan tot Maart 2011 en ontstaan tot November 2011), Web of Science (ontstaan tot Maart 2011 en ontstaan tot November 2011), Science Direct (ontstaan tot Maart 2011 en ontstaan tot Februarie 2012), Wiley Online Library (ontstaan tot Maart 2011 en ontstaan tot Februarie 2012), Springerlink (ontstaan tot April 2011 en ontstaan tot Februarie 2012), EBSCOhost [Academic Search Premier en CAB abstracts (ontstaan tot Maart 2011 en ontstaan tot Februarie 2012), CINAHL (ontstaan tot Maart 2011 en ontstaan tot November 2011)], Scopus (ontstaan tot Maart 2011 en ontstaan tot November 2011) en Google Scholar (ontstaan tot Maart 2011 en ontstaan tot Februarie 2012). Verwysingslyste van artikels is ook met die hand nagegaan vir relevante kliniese proewe. Slegs kliniese proewe waarvan die volteks beskikbaar was, is ingesluit in die oorsig. Seleksiekriteria Ewekansige gekontroleerde proewe (EGP) is ingesluit met volwasse deelnemers (gemiddeld 18-64.99 jaar) van alle rasse/etniese groepe en geslag op statien-terapie met gerapporteerde miopatie simptome van onbekende oorsaak. Die intervensie was 'n suiwer orale supplement van CoQ10 ongeag die dosis, duurte en frekwensie, en die kontrole 'n plasebo, soortgelyke antioksidant, of geen intervensie. Uitkomste het ingesluit: die graad van miopatie simptome, vlakke van plasma kreatien kinase (U/L), intra-muskulêre CoQ10 (μmol/kg) en plasma CoQ10 (μmol/L), sowel as newe-effekte van CoQ10. Dataversameling en -analise Die hoof ondersoeker en een onafhanklike hersiener het die seleksie van studies en data-ekstraksie onderneem en die risiko vir sydigheid geassesseer deur gebruik te maak van die Cochrane Collaboration’s tool for assessing risk of bias. Outeurs van relevante kliniese proewe is geraadpleeg vir addisionele inligting Resultate Twee EGP is ingesluit in die oorsig met 'n totaal van 76 deelnemers. 'n Meta-analise kon nie uitgevoer word nie, dus is die oorsig beskrywend. Daar was te min EGP om te bewys dat roetine supplementasie van CoQ10 statien-geïnduseerde miopatiese simptome verbeter. Gevolgtrekkings Meer en groter EGP is nodig om die effektiwiteit van CoQ10 supplementasie in statien-geïnduseerde miopatie te bepaal. Konsensus moet bereik word ten opsigte van die definisie en metingsinstrument/e van miopatie sodat die resultate van toekomstige studies makliker vergelyk en verwerk kan word.

在2型糖尿病病人身上，常常併發高膽固醇血症，HMG CoA 還原酶的抑制劑常常用作治療這類病症。由於高膽固醇血症與胰島素抵抗和2型糖尿病有著密切關係，我們推測辛伐他汀對於2型糖尿病的發展有著保護和有利的作用。在這項研究中，我們主要測試了辛伐他汀 （10 nM； 24 hr）對於胰島β細胞主要功能的影響，包括其對於葡萄糖的胰島素分泌功能影響。我們假設，在肥胖/糖尿病（db⁺/ db⁺）小鼠分離的胰島，辛伐他汀可以恢復葡萄糖 （5 mM和15 mM）引起的胰島素分泌（加上降低的胰島素含量）。 / 在這個項目中，我們運用24周大的基因糖尿糖C57BL/KSJ +db/+db (db⁺/db⁺)肥鼠和相同年齡的無糖尿病C57BL/KSJ +m/+m (db⁺/m⁺)小鼠作為動物模型。通過應用obese/diabetic (db+/db+)和lean/non-diabetic (db+/m+)中分離的胰腺胰島和胰島β細胞，我們研究了胰腺胰島功能性障礙的潛在機理以及辛伐他汀對於恢復葡萄糖 （5 mM和15 mM）引起的胰島素分泌（加上降低的胰島素含量）的有利作用。資料清晰的顯示，葡萄糖引起的胰島素分泌和胰島素含量在obese/diabetic (db+/db+)的胰腺胰島中明顯低於在lean/non-diabetic (db⁺/m⁺)的胰腺胰島中。在24hr的辛伐他汀處理後，辛伐他汀恢復了葡萄糖 （5 mM和15 mM）引起的胰島素分泌（加上降低的胰島素含量）及葡萄糖 （15 mM）引起的胞內鈣離子變化。 / 在這個項目中，我們證明鈣敏感受體 （CaSR）在obese/diabetic (db⁺/db⁺)中的表達量明顯較低，而辛伐他汀的處理可以顯著性增加鈣敏感受體在obese/diabetic (db⁺/db⁺)胰島中的表達。有人建議說，obese/diabetic (db⁺/db⁺)的胰島中被抑制的鈣敏感受體表達與胰島β細胞的胰島分泌功能障礙有關。這暗示了辛伐他汀可能通過變構啟動鈣敏感受體來恢復obese/diabetic (db⁺/db⁺)胰島中葡萄糖引起的胰島素分泌和胰島含量。實驗也同樣証明辛伐他汀調節的PLA₂信號通路對於辛伐他汀改善obese/diabetic (db⁺/db⁺)胰島β細胞的胰島素分泌功能起著至關重要的作用。除此之外，我們的實驗結果證明高濃度的葡萄糖處理顯著的增加了obese/diabetic (db⁺/db⁺)細胞膜肌動蛋白骨架的密度，而辛伐他汀顯著的減少了這一變化。因此，obese/diabetic (db⁺/db⁺)胰島β細胞的胰島素分泌障礙是由肌動蛋白細胞骨架聚集阻礙胰島素顆粒胞吐引起的。而辛伐他汀通過解聚和重組肌動蛋白細胞骨架來改善obese/diabetic (db⁺/db⁺)胰島β細胞的胰島素分泌功能。 / 在這項研究中，我們的實驗結果證明葡萄糖可以顯著提高obese/diabetic (db⁺/db⁺)胰島β細胞內ROS的含量。而辛伐他汀處理部分降低了胰島β細胞內ROS的含量。除此之外，我們還研究了5 mM和15 mM葡萄糖對於內質網應力（ER-stress）相關的蛋白比如PERK, eIF2α 和IRE1表達的影響。這些內質網跨膜蛋白可以感應ER-stress從而啟動應力感測器來開啟複雜的信號通路。與lean/non-diabetic (db⁺/m⁺)相比，PERK and eIF2α在obese/diabetic (db⁺/db⁺)的胰島中表達量更低，這表明obese/diabetic (db⁺/db⁺)胰島β細胞的功能性障礙可能與ER-stress有關。而辛伐他汀的處理明顯的增加了這些蛋白的表達量，由此證明辛伐他汀還通過對抗ER-stress來保護obese/diabetic (db⁺/db⁺)胰島β細胞。 / 總而言之，我們的資料第一次證明了辛伐他汀通過PLA₂信號通路變構啟動鈣敏感受體來保護obese/diabetic (db⁺/db⁺)胰島β細胞（比如：恢復葡萄糖引發的胰島素分泌和提高減少的胰島素含量），還通過提高obese/diabetic (db⁺/db⁺)胰島β細胞中被抑制的ER-stress相關蛋白的表達量來抵抗ER-stress帶來的損傷。 / Diabetics often have hyperlipidemia as a co-morbidity. Despite the well-documented cholesterol-lowering properties of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in treating hypercholesterolemia, the beneficial effects of statins consumption in T2DM treatment are confusing. In the current study, we examined the effects of the simvastatin (10 nM; 24 hr) on β-cell function leading to insulin secretory response to glucose. We hypothesized that statins restore the blunted glucose (5 mM and 15 mM)-induced insulin secretion (plus the reduced insulin content) of isolated pancreatic islets of obese/diabetic (db⁺/db⁺) mice. / In the present study, genetically diabetic C57BL/KSJ +db/+db (db⁺/db⁺) mice at 24 week of age and their age-matched non-diabetic littermates C57BL/KSJ +m/+m (db⁺/m⁺) were used. Our results clearly showed that the suppressed glucose (5 mM and 15 mM)-induced insulin release (plus insulin content) and glucose (15 mM)-induced [Ca²⁺]i changes of isolated pancreatic islets of obese/diabetic (db⁺/db⁺) was restored after simvastatin (10 nM; 24 hr) treatment. / The biochemical existence of CaR in pancreatic islets of lean/non-diabetic (db⁺/m⁺) and obese/diabetic (db⁺/db⁺) mice was confirmed. The suppressed/down-regulated expression of CaR was associated to the blunted insulin secretion in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice, and it was markedly up-regulated by simvastatin (10 nM; 24 hr). The involvement of CaR-mediated PLA₂ signaling in simvastatin (10 nM; 24 hr)-induced restoration of glucose (15 mM)-induced insulin secretion in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice was investigated. Our results also showed that the increased density of plasma membrane actin cytoskeleton of obese/diabetic (db⁺/db⁺) mice was significantly decreased by simvastatin (10 nM; 24 hr) treatment. The simvastatin-induced depolymerization and remodeling of actin cytoskeleton may improve insulin secretion capability in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice. / The glucose (15 mM)-induced intracellular ROS level was significantly higher in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice. The elevated ROS level was partially diminished by simvastatin (10 nM; 24 hr) treatment. The protein expressions of PERK and eIF2α (ER stress proteins) were lower in pancreatic islet cells isolated from obese/diabetic (db⁺/db⁺) mice, suggesting that abnormal expresstion/activity of PERK and eIF2α would be coupled to the ER-stress mediated failure of pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice. As simvastatin (10 nM; 24 hr) up-regulated the protein expression of these proteins, this drug exerted protective effect on pancreatic β-cells against ER stress and restored the blunted glucose (15 mM)-induced insulin secretion (plus the reduced insulin content) in obese/diabetic (db⁺/db⁺) mice. / In conclusion, our results demonstrate, for the first time, that simvasatatin (a HMG-CoA reductase inhibitor) (10 nM; 24 hr) provides beneficial effects (i.e. restoration of the blunted glucose-induced insulin release plus the reduced insulin content) in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice via the allosteric modification/up-regulation of extracellular calcium-sensing receptor through the PLA₂ signaling pathway, and provides protective/antioxidant effects against oxidative stress caused by chronic hyperglycemia in pancreatic β-cells of obese/diabetic (db⁺/db⁺) mice by up-regulating protein expression of the suppressed ER stress sensors and antioxidant enzyme. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Au, Lai Shan. / Thesis (Ph.D.) Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 458-532). / Abstracts also in Chinese.

Surgical myocardial revascularization remains the standard of care for patients with multi-vessel coronary artery disease. A growing body of evidence indicates that systemic inflammation and myocardial oxidative stress are associated with the development of postoperative atrial fibrillation (POAF) and low cardiac output syndrome in patients undergoing cardiac surgery. Statins have been shown to exert rapid anti-inflammatory and antioxidant effects by inhibiting myocardial NOX2 oxidases and by increasing the bioavailability of nitric oxide (NO). However, whether these so-called pleiotropic effects of statins result in improved patient outcomes remains to be established. To provide further insights into the mechanisms of action and impact on clinical outcomes of peri-operative statin treatment in patients undergoing cardiac surgery, I studied the molecular mechanisms underlying the myocardial nitroso-redox balance in samples of the right atrial appendages (RAA) obtained before (PRE) and after cardiopulmonary bypass (CPB) and reperfusion (POST) and setup two double-blind randomised placebo-controlled trials: 1) STARR (Statin Treatment on Atrial Refractoriness and Reperfusion injury), which tested the effect of Atorvastatin (80 mg once daily for up to 6 days before surgery and 5 days after) on the atrial effective refractory period (AERP, over 4 post-operative days) and superoxide production in paired PRE- and POST- RAA samples from 60 patients 2) STICS (Statin Treatment In Cardiac Surgery), which assessed the effects of peri-operative treatment with Rosuvastatin (20mg od) on POAF (assessed by continuous holter ECG monitoring for 5 days postoperatively) and myocardial injury (assessed by serial troponin I measurements) in 1922 patients undergoing elective cardiac surgery. I observed that atrial superoxide production increased significantly after reperfusion due to increased mitochondrial and NOX2 oxidase activity and to uncoupling of NOS activity. NOS activity in RAA samples decreased significantly after reperfusion (by 60%), but this reduction was not prevented by BH4 supplementation (10 μM) or NOX2 inhibition. Instead, I identified increased endothelial NOS S-glutathionylation as the main mechanism responsible for NOS uncoupling after reperfusion. In STARR, atorvastatin prevented increase in RAA superoxide production, maintained the functionally coupled status of NOS and NO bioavailability after reperfusion but had no measurable effect on postoperative AERP. In STICS, treatment with rosuvastatin significantly reduced LDL-C concentration by 48 hours after surgery but had no effect on the incidence of POAF (203 (21%) of the Rosuvastatinallocated patients vs. 197 (20%) of the placebo-allocated patients) or on perioperative myocardial damage (P = 0.80). Pre-defined subgroup analyses (age, sex, prior statin use, baseline troponin concentration, duration of randomized treatment before surgery, type of cardiac surgery, and postoperative use of anti-inflammatory drugs) did not identify any category of patient who benefited from perioperative rosuvastatin treatment. Nor were there beneficial effects on any of the other in-hospital clinical outcomes that were assessed. In conclusion, cardiac surgery on CPB is associated with myocardial nitroso redox imbalance that is reversed by perioperative intensive therapy with statins. However, these effects have no beneficial effects on common in-hospital complications after elective cardiac surgery. Although the benefits of long-term statin therapy in patients requiring myocardial revascularization are well established, the work presented in this thesis does not support routine use of perioperative intensive therapy with statins for the prevention of postoperative complications in patients undergoing elective cardiac surgery.