[Show abstract][Hide abstract] ABSTRACT: Background: Elevated low density lipoprotein cholesterol (LDLc) is one of the major risk factors
for premature cardiovascular diseases (CVD). Thus, therapeutic approaches aim at reducing LDLc.
PCSK9 (Proprotein Convertase Subtilisin/Kexin type 9) has been shown to be a key regulator of
the LDLR-mediated cholesterol clearance pathway. Many preclinical and clinical studies confirm
the LDLc-lowering effect of PCSK9 inhibition, and emphasize PCSK9 as a potential novel target
for the treatment of CVD.
Aim: Proof of concept study for AFFITOPE®-based (AT04A) anti-PCSK9 immunization in the
APOE*3Leiden.CETP mouse model and its safety aspects.
Methods: AT04A vaccine was administered subcutaneously in APOE*3Leiden.CETP mice. Control
and vaccine treated mice were fed Western-type diet for 18 weeks. Antibody titers and
concentration, and their affinity towards PCSK9, as well as plasma lipids were monitored
throughout the whole study by ELISA, Biacore® and FPLC, respectively. Moreover, body weight
(BW), food intake (FI) and liver enzymes (ALT and AST) were measured. The progression of
atherosclerotic lesion development was evaluated by histological analysis of serial cross-sections
from the aortic sinus.
Results: AT04A vaccine induced antibodies (mean titers up to ODmax/2=12,000 and mean
concentration up to 250 μg/mL), which significantly reduced the plasma total cholesterol (TC) (-
53%, P<0.001) and triglycerides (TG) (-46%, P<0.001), contained in the apoB-containing
lipoproteins, in comparison to the control. Moreover, immunization neither altered FI or BW, nor
plasma liver enzymes concentration. Furthermore, anti-PCSK9 immunization resulted in a higher
percentage of undiseased aortic segments (+119%, p=0.026), decreased segments with severe
lesions (-64%, p=0.051) and a decrease in atherosclerotic lesion area (-64%, P=0.004) as
compared to the control.
Conclusions and Outcome: AT04A vaccine is highly immunogenic and atheroprotective in
APOE*3Leiden.CETP mice. The induced antibodies are able to decrease significantly plasma lipids
and atherosclerotic lesions progression in the aorta. A phase I clinical study with AT04A and with
a second vaccine candidate AT06A is scheduled for Q3/2015.
[Show abstract][Hide abstract] ABSTRACT: Perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) are stable perfluoroalkyl sulfonate (PFAS) surfactants, and PFHxS and PFOS are frequently detected in human biomonitoring studies. Some epidemiological studies have shown modest positive correlations of serum PFOS with non-high-density lipoprotein (HDL)-cholesterol (C). This study investigated the mechanism underlying the effect of PFAS surfactants on lipoprotein metabolism. APOE*3-Leiden.CETP mice were fed a Western-type diet with PFBS, PFHxS, or PFOS (30, 6, and 3 mg/kg/day, respectively) for 4-6 weeks. Whereas PFBS modestly reduced only plasma triglycerides (TG), PFHxS and PFOS markedly reduced TG, non-HDL-C, and HDL-C. The decrease in very low-density lipoprotein (VLDL) was caused by enhanced lipoprotein lipase-mediated VLDL-TG clearance and by decreased production of VLDL-TG and VLDL-apolipoprotein B. Reduced HDL production, related to decreased apolipoprotein AI synthesis, resulted in decreased HDL. PFHxS and PFOS increased liver weight and hepatic TG content. Hepatic gene expression profiling data indicated that these effects were the combined result of peroxisome proliferator-activated receptor alpha and pregnane X receptor activation. In conclusion, the potency of PFAS to affect lipoprotein metabolism increased with increasing alkyl chain length. PFHxS and PFOS reduce plasma TG and total cholesterol mainly by impairing lipoprotein production, implying that the reported positive correlations of serum PFOS and non-HDL-C are associative rather than causal.
Full-text · Article · Jun 2011 · Toxicological Sciences
[Show abstract][Hide abstract] ABSTRACT: Remote ischaemic preconditioning (RIPC) is a strategy to protect a target organ against ischaemia-reperfusion injury (IRI) by inducing short-term ischaemia/reperfusion (I/R) in a remote organ. RIPC of the kidney by temporary limb occlusion would be a safe, inexpensive and noninvasive method to prevent renal damage in, e.g., transplantation and aortic surgery. We investigated whether brief hind limb occlusion can protect against renal IRI and whether this protection is adenosine dependent.
Rats underwent either no RIPC, unilateral RIPC or bilateral RIPC. The preconditioning stimulus was either continuous (12'/12' I/R) or fractionated (three times 4'/4' I/R). After the last reperfusion period, we induced 25' ischaemia in the right kidney.
After 24 h of reperfusion, renal function was improved by 30-60% in both bilateral RIPC groups and in the fractionated unilateral group. Renal tubule damage and kidney injury molecule-1 expression were reduced in three of four RIPC groups. Treatment with the adenosine receptor blocker 8-(p-sulfophenyl)theophylline had no effect on fractionated or continuous RIPC.
Brief hind limb ischaemia induces protection against renal IRI, which makes this a promising strategy to prevent renal IRI in a clinical setting. Bilateral RIPC was more effective than unilateral RIPC, and this protection occurs via an adenosine-independent mechanism.
No preview · Article · Mar 2011 · Nephrology Dialysis Transplantation
[Show abstract][Hide abstract] ABSTRACT: Selective cyclooxygenase-2 inhibition by rofecoxib was associated with increased risk of cardiovascular events. We hypothesized that concomitant treatment with thromboxane prostanoid receptor antagonist S18886 might ameliorate possible negative effects. We evaluated the effects of S18886, rofecoxib, and the interaction of both compounds in a combined treatment on myocardial infarct (MI) size and cardiac function after experimental ischemia/reperfusion injury in hyperlipidemic APOE*3Leiden transgenic mice.
Prospective, randomized, control trial.
Hyperlipidemic APOE*3Leiden transgenic mice.
After four weeks of feeding an atherogenic diet, MI was induced by a 30-min ligation of the left anterior descending coronary artery, followed by reperfusion. Oral compound treatment was initiated 90 mins before MI, and continued daily by gavage for seven days. Four treatment groups (n = 12, each) were studied: solvent (Control), S18886, rofecoxib, and S18886 plus rofecoxib.
One week after MI, the mice were anesthetized and cardiac function was quantified by left ventricular (LV) pressure-volume relationships obtained by miniature pressure-conductance catheters. The ischemic area was measured by morphometry and expressed as percentage of LV area. No significant differences in infarct size were found between groups. Compared with control, treatment with S18886 did not affect heart function whereas the rofecoxib group had significantly lower cardiac output (4.5 +/- 0.8 vs. 3.2 +/- 1.1 mL/min, p < 0.01), lower ejection fraction (40 +/- 8 vs. 27 +/- 11%, p < 0.005), and increased end-systolic volume (18.6 +/- 5.7 vs. 28.6 +/- 9.0 muL, p < 0.05). The group with combined (S18886+rofecoxib) treatment was not different from control. Statistical analysis showed significant interactive effects between S18886 and rofecoxib indicating that negative effects of rofecoxib on cardiac function were prevented by S18886 treatment.
Rofecoxib treatment reduced global and systolic LV function after ischemia-reperfusion injury in APOE*3Leiden mice. These negative effects are prevented by combined treatment with thromboxane prostanoid-receptor antagonist S18886 (terutroban).
Full-text · Article · Sep 2008 · Critical care medicine
[Show abstract][Hide abstract] ABSTRACT: Atherosclerosis is a multifactorial highly-complex disease with numerous etiologies that work synergistically to promote lesion development. The ability to develop preventive and ameliorative treatments will depend on animal models that mimic the human subject metabolically and pathophysiologically and will develop lesions comparable to those in humans. The mouse is the most useful, economic, and valid model for studying atherosclerosis and exploring effective therapeutic approaches. Among the most widely used mouse models for atherosclerosis are apolipoprotein E-deficient (ApoE-/-) and LDL receptor-deficient (LDLr-/-) mice. An up-and-coming model is the ApoE*3Leiden (E3L) transgenic mouse. Here, we review studies that have explored how and to what extent these mice respond to compounds directed at treatment of the risk factors hypercholesterolemia, hypertriglyceridemia, hypertension, and inflammation. An important outcome of this survey is that the different models used may differ markedly from one another in their response to a specific experimental manipulation. The choice of a model is therefore of critical importance and should take into account the risk factor to be studied and the working spectrum of the compounds tested.