Tacrolimus-induced elevation in plasma triglyceride concentrations after administration to renal transplant patients is partially due to a decrease in lipoprotein lipase activity and plasma concentrations.

BACKGROUND: Hyperlipidemia is a frequent and persistent complication in solid organ transplant recipients, leading to the high occurrence of cardiovascular disease in this patient population. Lipid abnormalities including increased total cholesterol, triglycerides (TG), and low-density lipoprotein-cholesterol have been reported frequently in transplantation patients and a variety of immunosuppressive therapies seem to be one of the main factors that influence posttransplant lipidemic profiles. For many years, tacrolimus (TAC) has been used as an immunosuppressive drug in transplantation. The aim of our investigation was to determine the effect of TAC administration on the plasma lipid profile and some key regulatory proteins of plasma lipid metabolism including cholesterol ester transfer protein, hepatic lipase and lipoprotein lipase (LPL) within renal transplant patients. METHODS: Twenty-five renal transplant patients were recruited and received TAC therapy, of which nine of these patients were treated with statin therapy for dyslipidemia. The effects of TAC on plasma total cholesterol, TG, HDL-C, low-density lipoprotein-cholesterol, cholesterol ester transfer protein, hepatic lipase and LPL concentration and activity were determined from patients plasma samples collected before the transplant surgery (baseline), and weekly for four consecutive weeks after surgery and TAC administration. RESULTS: We observed that TAC significantly increases plasma TG concentrations and reduces LPL plasma concentration and activity in renal transplant patients, independent of any lipid lowering drug treatment patients received. CONCLUSIONS: Taken together, these findings suggest that the reduction in LPL activity, partly due to the decrease of plasma LPL concentration after TAC administration may be an explanation for hypertriglyceridemia observed in patients administered TAC.

Discovery and development of toll-like receptor 4 (TLR4) antagonists: a new paradigm for treating sepsis and other diseases.

Sepsis remains the most common cause of death in intensive care units in the USA, with a current estimate of at least 750,000 cases per year, and 215,000 deaths annually. Despite extensive research still we do not quite understand the cellular and molecular mechanisms that are involved in triggering and propagation of septic injury. Endotoxin (lipopolysaccharide from Gram-negative bacteria, or LPS) has been implicated as a major cause of this syndrome. Inflammatory shock as a consequence of LPS release remains a serious clinical concern. In humans, inflammatory responses to LPS result in the release of cytokines and other cell mediators from monocytes and macrophages, which can cause fever, shock, organ failure and death. A number of different approaches have been investigated to try to treat and/or prevent the septic shock associated with infections caused by Gram-negative bacteria, including blockage of one or more of the cytokines induced by LPS. Recently several novel amphipathic compounds have been developed as direct LPS antagonists at the LPS receptor, TLR4. This review article will outline the current knowledge on the TLR4-LPS synthesis and discuss the signaling, in vitro pre-clinical and in vivo clinical evaluation of TLR4 antagonists and their potential use in sepsis and a variety of diseases such as atherosclerosis as well as hepatic and renal malfunction.

Cyclosporine A and Rapamycin induce in vitro cholesteryl ester transfer protein activity, and suppress lipoprotein lipase activity in human plasma.

PURPOSE: Cyclosporine A (CsA), Rapamycin (RAPA), Tacrolimus (FK-506) and Mycophenolate mofetil (MMF) are immunosuppressants that are widely used in solid organ transplant patients. However, some of these drugs have been reported to cause dyslipidemia in patients. Our aim was to determine the effects of these drugs on in vitro cholesteryl ester transfer protein (CETP), hepatic lipase (HL) and lipoprotein lipase (LPL) activity within human plasma. METHODS: We measured CETP activity in human normolipidemic plasma with and without drug treatment, by measuring the incorporation of labeled cholesteryl ester into lipoproteins. To further confirm the result, we also measured recombinant CETP (rCETP) activity with and without drug treatment. We measured HL and LPL activity in post-heparin normal human plasma in the presence and absence of the drugs by measuring the release of fatty acids from radiolabeled triolein. RESULTS: We found an increase in CETP activity in human normolipidemic plasma and rCETP treated with CsA and RAPA. By contrast, CETP activity was not altered significantly in the presence of FK-506 and MMF. LPL activity in post-heparin normal human plasma was suppressed following the co-incubation with CsA, RAPA, FK-506 or MMF whereas HL activity remained unaffected. CONCLUSIONS: The increase in CETP activity and suppression in LPL activity following CsA and RAPA treatment observed in the present study may be associated with elevated LDL cholesterol levels and hypertriglyceridemia seen in patients administered these drugs.