The Effects Of CRP And Short-term Intensive Atorvastatin Therapy On Vascular Endothelial Dysfunction And Related Mechanisms Investigation

BackgroundModern anesthesiology quickly developed during recent years, and it developed from simple intraoperative analgesia in early phage to alleviating patients’ intraoperative pain, improving patient safety, and providing better operative condition for surgeon. At the same time, with the development of anesthesiology, anesthesiology should also include intraoperative organ protection, perioperative patient management for prognosis after operation, and so on. Cardiovascular system is the most important system in anesthesia, and its complication is also the main perioperative complication and the main cause resulting in death during or after operation, which is closely associated with the known or unknown cardiovascular diseases especially ischemic heart disease in patients undergoing noncardiac surgery. Unfortunately despite an improvement in the safety of modern anesthesia, better drugs and advances in perioperative patient monitoring, the mortality from myocardial infarction, arrhythmia and heart failure after noncardiac surgery is still high, especially in old patients and patients undergoing vascular surgery. The related mechanism is unclear, however, it is deemed to be associated with activated sympathetic nerve system due to stress before operation, it is also associated with perioperative blood pressure fluctuation and anesthetics used during operation. Certainly, known or unknown cardiovascular diseases are still the most important related factors.Atherosclerosis is a multiple-factor disease, and hyperlipidemia, age, gender, hypertension, and diabetes are recognized as the classic risk factors of atherosclerosis. C-reactive protein (CRP) is an important biomarker of inflammation and the strong predictive factor of cardiovascular events and long-term prognosis. Recent many studies demonstrated that CRP itself could increase the adhesion molecule secretion by endothelium cell, promote the secretion of tissue factor (TF), tissue factor pathway inhibitor (TFPI), and matrix metalloproteinases (MMPs), which would promote coagulation and extracellular matrix (ECM) degradation, and induce the expression imbalance between nitric oxide (NO) and endothelin-1(ET-1) in endothelium cells and vascular smooth muscle cells (VASC). ARIC trial and JUPITER trial both demonstrated that health population with normal blood lipids but higher CRP levels could obtain significant benefits of cardiovascular events from reduced CRP by active statins therapy. This meant decreasing CRP might be the potential anti-atherosclerosis pathway. Accordingly, many researchers think CRP can not only act as the inflammatory factor and predictive factor of atherosclerotic diseases, but might be the risk factor of atherosclerosis and directly participate in atherogenesis and cardiovascular events. However, it is still unclear about the related mechanism. Recent years, many large-scale clinical trials have already well demonstrated that hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductases inhibitor (namely statins) could greatly decrease cardiovascular events for patients with atherosclerotic diseases. Accordingly, statins played pivotal role in primary and secondary prevention of atherosclerotic diseases. Traditional opinion thought statins prevented atherosis and decreased cardiovascular events mainly through decreasing the serum levels of cholesterol, however, increasing evidences demonstrated that, except for lipids-lowing effects, the benefits of statins in atherosclerotic patients were also due to its non-lipids-lowing effects such as anti-inflammatory, anti-oxidant and anti-thrombotic effects.A series of clinical trials including PROVE IT、TIMI22、TNT、IDEAL trials all demonstrated that patients with coronary artery disease could obtain early and late benefits from intensive statins therapy. Recent ARMYDA and NAPLES II trial also demonstrated that short-term intensive atorvastatin therapy could greatly improve the prognosis of acute coronary syndrome (ACS) patients undergoing early percutaneous coronary intervention (PCI). At present, it was accepted that the benefits from short-term statins therapy was associated with the pleiotropy of statins such as anti-inflammatory property but not its lipids-lowing effect. However, the concrete mechanism was still unclear.It is well known that the stability of vascular endothelial function is very important for patients with coronary artery disease (CAD), because endothelial dysfunction is closely associated with cardiovascular events, and improving endothelial function can significantly decrease the risk of cardiovascular events for CAD patients. In clinical practice, many patients undergoing surgery operation also suffered from known and undiagnosed cardiovascular diseases especially CAD. Accordingly, it becomes an important clinical problem to manage these patients to decrease cardiovascular events risk during peroperative period, because these patients may modulate cardiovascular drugs before operation. ARMYDA and NAPLES Ⅱ trial both demonstrated short-term intensive atorvastatin therapy could greatly decrease cardiovascular events risk for ACS patients undergoing early PCI, in addition, it could also improve the prognosis. However, it is unclear whether short-term intensive atorvastatin therapy could decrease preoperative cardiovascular events risk for those patients with known or undiagnosed CAD. Certainly, the question should be answered by some large-scale random controlled trials. The present study aimed to evaluate the effects of short-term intensive atorvastatin therapy on vascular endothelial function and determine the related mechanism in animal model.Part Ⅰ The effects of CRP on vascular endothelial function and related mechanismsObjective:To determine the effect of CRP on vascular endothelial function in hyperlipidemic rabbits and investigate the related mechanism.Methods:The levels of basic total cholesterol, low-density lipoprotein cholesterol, triglyceride, CRP, tumor necrosis factor-α (TNF-α), interleukin-6(IL-6), nitric oxide (NO) and endothelin-1(ET-1) were respectively measured in rabbits, endothelium-dependent vasorelaxation function was also evaluated. Animals were randomly divided into two groups:PCAT(-) and PCAT(+) group (removing or keeping pericarotid adipose tissue (PCAT)). Both of the two groups were exposed to a high-fat diet for six-week, and then sustained CRP treatment was performed for a week, at this time point all the above parameters were remeasured. In addition, mRNA and protein expression of TNF-α, IL-6, and macrophage chemoattractant protein-1(MCP-1) were respectively evaluated by Polymerase Chain Reaction and immunoblotting in PCAT and cultured adipocytes treated by CRP.Results:High-fat diet greatly increased the serum lipids and inflammatory markers, induced endothelial dysfunction and imbalance between NO and ET-1, increased mRNA and protein expression of TNF-a, IL-6, MCP-1and enhanced macrophage infiltration of PCAT. CRP treatment could further promote macrophage infiltration of PCAT, induce the imbalance between NO and ET-1, aggravate endothelial dysfunction especially in PCAT(+) arteries, and could also enhance the above-mentioned mRNA and protein expression in PCAT and cultured adipocytes.Conclusions:CRP could significantly promote endothelial dysfunction in high-fat diet rabbits especially in PCAT(+) groups, which may be partly mediated by activating inflammatory reaction of adipose tissue.Part II The effects of short-term intensive atorvastatin therapy on the endothelial function in hyperlipidemic rabbits and related mechanismObjectve:To determine the effect of short-term intensive atorvastatin therapy on vascular endothelial function and mechanism in hyperlipidemic rabbits.Methods:Basic total cholesterol, low-density lipoprotein cholesterol, triglyceride, CRP, tumor necrosis factor-a (TNF-a), interleukin-6(IL-6), nitric oxide (NO), endothelin-1(ET-1) and endothelium-dependent vasorelaxation function were respectively measured in rabbits. After six-week high-fat diet, animals were randomly divided into two groups:PCAT(-) and PCAT(+) group (removing or keeping pericarotid adipose tissue (PCAT)). After that, continue CRP treatment was performed for a week, and then all above parameters were remeasured. In addition, mRNA and protein expression of TNF-a, IL-6, and macrophage chemoattractant protein-1(MCP-1) were respectively evaluated by Polymerase Chain Reaction and immunoblotting in PCAT of different groups and cultured adipocytes treated by CRP with different dose. Results:High-fat diet greatly increased the serum lipids, inflammatory markers, induced endothelial dysfunction and imbalance between NO and ET-1, and increased mRNA and protein expression of TNF-a, IL-6, MCP-1and enhanced macrophage infiltration of PCAT. CRP treatment could further promote macrophage infiltration of PCAT, induce the imbalance between NO and ET-1, aggravate endothelial dysfunction especially in PCAT(+) arteries, and could also enhance above-mentioned mRNA and protein expression in PCAT and cultured adipocytes.Conclusions:CRP could significantly promote endothelial dysfunction in high-fat diet rabbits especially in PCAT(+) groups, which may be partly mediated by activating inflammatory reaction of adipose tissue. General conclusions of full text1. High-fat diet could cause significant hyperlipidemia and endothelial dysfunction, together with increased serum levels of inflammatory factors (CRP、IL-6、TNF-α) and activate5-LO pathway to enhance mRNA and protein expression of inflammatory factors (CRP、IL-6、TNF-α、MCP-1).2. CRP could significantly promote endothelial dysfunction in high-fat diet rabbits especially in PCAT(+) groups, which may be partly mediated by activating inflammatory reaction of adipose tissue.3. Except for bloos lipids, serum inflammatory factors, inflammatory factors expression were significantly decreased and endothelial function was obviously improved after short-term intensive atorvastatin therapy but not low-dose therapy. 4. No expression changes of inflammatory factors including CRP, IL-6, TNF-a, MCP-1, and5-LO were observed after short-time low-dose atorvastatin therapy in LPS-treated adipocytes, however, the expression was greatly attenuated by intensive atorvastatin therapy and5-LO inhibitor CDC.5. CRP could enhance inflammatory reaction of PCAT and induce endothelial dysfunction, and short-term intensive atorvastatin therapy could significantly improve endothelial dysfunction induced by HFD, which may be partly due to attenuating PCAT inflammation through inhibiting5-LO pathway.