Federico Bigazzi

Chronic activation of peroxisome proliferator-activated receptor-α with fenofibrate prevents alterations in cardiac metabolic phenotype without changing the onset of decompensation in pacing-induced heart failure

Severe heart failure (HF) is characterized by profound alterations in cardiac metabolic phenotype, with down-regulation of the free fatty acid (FFA) oxidative pathway and marked increase in glucose oxidation. We tested whether fenofibrate, a pharmacological agonist of peroxisome proliferator-activated receptor-α, the nuclear receptor that activates the expression of enzymes involved in FFA oxidation, can prevent metabolic alterations and modify the progression of HF. We administered 6.5 mg/kg/day p.o. fenofibrate to eight chronically instrumented dogs over the entire period of high-frequency left ventricular pacing (HF + Feno). Eight additional HF dogs were not treated, and eight normal dogs were used as a control. [3H]Oleate and [14C]Glucose were infused intravenously to measure the rate of substrate oxidation. At 21 days of pacing, left ventricular end-diastolic pressure was significantly lower in HF + Feno (14.1 ± 1.6 mm Hg) compared with HF (18.7 ± 1.3 mm Hg), but it increased up to 25 ± 2 mm Hg, indicating end-stage failure, in both groups after 29 ± 2 days of pacing. FFA oxidation was reduced by 40%, and glucose oxidation was increased by 150% in HF compared with control, changes that were prevented by fenofibrate. Consistently, the activity of myocardial medium chain acyl-CoA dehydrogenase, a marker enzyme of the FFA β-oxidation pathway, was reduced in HF versus control (1.46 ± 0.25 versus 2.42 ± 0.24 μmol/min/gram wet weight (gww); p < 0.05) but not in HF + Feno (1.85 ± 0.18 μmol/min/gww; N.S. versus control). Thus, preventing changes in myocardial substrate metabolism in the failing heart causes a modest improvement of cardiac function during the progression of the disease, with no effects on the onset of decompensation.

Cellular cholesterol efflux and cholesterol loading capacity of serum: effects of LDL-apheresis

High LDL-cholesterol (LDL-C) characterizes familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH). LDL-apheresis, used in these patients to reduce LDL-C levels, has been shown to also affect HDL levels and composition. We studied LDL-apheresis effects on six FH and nine FCH subjects’ serum capacity to modulate cellular cholesterol efflux, an index of HDL functionality, and to load macrophages with cholesterol. Serum cholesterol efflux capacity (CEC) and macrophage cholesterol loading capacity (CLC) were measured before, immediately after, and two days after LDL-apheresis. The procedure reduced total cholesterol (TC), LDL-C, and apoB plasma levels (−69%, −80% and −74%, respectively), parameters only partially restored two days later. HDL-C and apoA-I plasma levels, reduced after LDL-apheresis (−27% and −16%, respectively), were restored to almost normal levels two days later. LDL-apheresis reduced serum aqueous diffusion (AD) CEC, SR-BI-CEC, and ABCA1-CEC. AD and SR-BI were fully restored whereas ABCA1-CEC remained low two days later. Sera immediately and two days after LDL-apheresis had a lower CLC than pre-LDL-apheresis sera. In conclusion, LDL-apheresis transiently reduces HDL-C levels and serum CEC, but it also reduces also serum capacity to deliver cholesterol to macrophages. Despite a potentially negative effect on HDL levels and composition, LDL-apheresis may counteract foam cells formation.

Up regulation of C3, C4, and soluble intercellular adhesion molecule-1 co-expresses with high sensitivity C reactive protein in familial hypoalphalipoproteinaemia: further evidence of inflammatory activation

Objective: To test the working hypothesis that inflammation underlying precocious and severe coronary atherosclerotic disease in familial hypoalphalipoproteinaemia (FH) can be mediated by up regulation of the innate immune response. Methods and results: 52 patients with FH were compared with 52 healthy controls with regard to immune system markers such as C reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), C3c, and C4. Patients differed from controls in their significantly lower concentrations of high density lipoprotein cholesterol (30.2 (4.0) v 50.5 (13.6) mg/dl, p < 0.0001) and apolipoprotein A I (113.2 (19.9) v 148.7 (25.1) mg/dl, p < 0.0001) and their higher triglyceride (139.3 (63.2) v 81.4 (41.7) mg/dl, p < 0.0001) and CRP plasma concentrations (median 0.33 mg/dl, range 0.02–4.66 mg/dl v median 0.07 mg/dl, range 0.02–0.85 mg/dl, p < 0.0001), but not in their total cholesterol and low density lipoprotein cholesterol concentrations. Concentrations of protein complement were higher in patients (C3: 150.8 (42.3) v 101.9 (17.4) mg/dl, p < 0.0001; C4: 35.5 (13.6) v 22.8 (6.4) mg/dl, p < 0.0001) and sICAM-1 concentrations were more than double those found in the controls (335.1 (107.5) v 159.5 (78.2) mg/dl, p < 0.0001). Conclusions: Increased concentrations of sICAM-1, C3c, and C4 co-express with high concentrations of CRP in FH. The lack of signs and symptoms of inflammation in these patients may suggest that the immune response is up regulated as part of the pro-inflammatory mechanisms that are activated in this atherogenic condition.

Myeloperoxidase modulation by LDL apheresis in familial hypercholesterolemia.

BackgroundMyeloperoxidase (MPO) is a marker of plaque vulnerability and a mechanistic bridge between inflammation and cardiovascular disease, and thus is a suitable target for therapeutic strategy against cardiovascular disease.MethodsSince hypercholesterolemia is associated with atherosclerosis and inflammation, we tested whether MPO serum levels were up-regulated in Familial Hypercholesterolemia (FH) and whether acute reduction of total cholesterol (TC) would also reduce MPO concentration. FH subjects undergoing LDL-apheresis (LDL-A) treatment are a paradigmatic clinical model where TC rapidly plunges from extremely high to extremely low levels after selective LDL removal, and then spontaneously rebounds to baseline conditions. This clinical setting allows multiple intra-patient observations at different plasma TC concentrations. We measured MPO levels in serum by ELISA tests, and in peripheral leukocytes by immunofluorescence, to learn whether they were affected by the changes in TC levels. Serum MPO was measured before and serially up to the 14th day following LDL-A.ResultsIn both serum and peripheral leukocytes, MPO concentrations were i) higher than in sex- and age-matched healthy controls (p < 0.01); ii) decreased with TC reduction; iii) parallel with TC time course; iv) correlated with plasma TC. At regression analysis, plasma TC was the only variable considered that influenced MPO serum levels (β 0.022 ± 0.010, p < 0.0001).ConclusionsIn FH the MPO serum levels were modulated through changes in the TC concentrations carried out by LDL-A. Further study is needed to determine whether reduced MPO levels obtained by LDL-A could have any therapeutic impact.

Upregulation of the immune system in primary hypercholesterolaemia: effect of atorvastatin therapy.

Objectives.  High levels of plasma high sensitivity C‐reactive protein (CRP), sensitive to therapy with statins, have been described in hypercholesterolaemia. In vitro evidence shows that CRP activates the complement system, which, in turn, leads to an increased expression of ICAM‐1. Our objectives were to verify whether primary hypercholesterolaemia (PHC) is associated with an upregulation of the inflammatory/immune response, and whether this is sensitive to atorvastatin.

Genetic score based on high-risk genetic polymorphisms and early onset of ischemic heart disease in an Italian cohort of ischemic patients

Several single-nucleotide polymorphisms (SNPs) have been recognized as associated with ischemic heart disease (IHD) although the optimal set of risk genotypes has not be identified. This study aimed to examine whether identified high-risk SNPs are associated with early onset of IHD. In the GENOCOR study, 44 high-risk SNPs were genotyped in 114 patients with early onset of IHD (46.2 ± 5.1 years) and 384 patients with late onset of IHD (60.7 ± 5.9 years). The associations between individual SNPs and early onset IHD were assessed. A multilocus genetic risk score (GRS) for each associated risk genetic markers was constructed by summing the number of risk alleles. The SNPs significantly associated with IHD were: -482C>T of Apolipoprotein C III gene (ApoC3, p=0.02); 1171 5A>6A of Matrix metalloproteinase 3 stromelisine I gene (p=0.01); G98T of Selectin E gene (p=0.05); C/G of 9p21.3 locus (p=0.01). Likelihood ratio test showed a strong interaction for increasing risk of early IHD between the presence of ApoC3 and 9p21.3 locus with hypertriglyceridemia (p=0.0008, 0.0011) as well as between 9p21.3 locus and smoking (p=0.0010) after correction for multiple testing. The OR for premature IHD for GRS unit was 1.3 (95% CI 1.1-1.6, p=0.001). Patients in the top tertile of GRS were estimated to have a 3.2-fold (95% CI 1.5-6.8; p=0.001) increased risk of early IHD compared with those in the bottom tertile. The results show that currently identified high-risk SNPs confer an additive biomarker for cardiovascular events. GRS may provide important incremental information on the genetic component of IHD.

Tangier Disease in Severely Progressive Coronary and Peripheral Artery Disease

A 37-year-old man was first referred to our lipid clinic in December 2007 for plasma lipid alteration. He presented with large, orange tonsils (Figure 1) and hepatosplenomegaly. There was no evidence of corneal opacities nor of other ocular abnormalities, and there were no nervous system abnormalities as assessed by sensitive and motor electromyography. Figure 1. Orange large tonsils. Hematologic abnormalities included thrombocytopenia and erythrocytes with altered morphology (stomatocytes; Figure 2) and function (decreased osmotic resistance). Serum levels of total cholesterol, triglycerides, and high-density lipoprotein (HDL) cholesterol were 58, 184, and 4 mg/dL, respectively; plasma apolipoprotein A-I concentrations were very low (3.9 mg/dL); and apolipoprotein A-II plasma levels were 1.7 mg/dL. Figure 2. Peripheral blood erythrocytes with numerous stomatocytes. The patient’s father (58 years of age) had serum levels of total cholesterol, HDL cholesterol, and apolipoprotein A-I of 127, 25, and 99.5 mg/dL, respectively. Moreover, he had a …

HDL and clinical and biochemical correlates in Italian non-smoker women.

Abstract High-density lipoprotein (HDL)-cholesterol levels, inversely related to the risk of myocardial infarction, are determined by genetic and environmental factors. The aim of this study was to evaluate the prevalence of low and high HDL plasma levels and the influence of environmental factors and lipid profile in an Italian non-smoker female population. HDL, apolipoprotein A-I, apolipoproteins, lipids and estrogen plasma levels were measured in a population of 1471 women with a mean age of 45±14years. HDL values ≤35mg/dl were noted in 11.2% of the subjects, showing 2.4% coronary heart disease (CHD) prevalence. The 90th percentile was characterized by HDL levels ≥66mg/dl and the absence of coronary atherosclerosis. Total cholesterol, apolipoprotein B and triglycerides (r=−0.31, p<0.0001) were the main determinants of HDL levels; apolipoprotein E, estrogen use, body mass index (BMI), alcohol consumption and age showed a weaker correlation. Apolipoprotein A-I concentration was influenced more notably by estrogen use, total cholesterol and apolipoprotein E; levels of triglycerides, apolipoprotein B, BMI, age and alcohol consumption are less important. The parameters considered here, taken together, explain HDL and apolipoprotein A-I variability of approximately 31% and 24%, respectively. A surprisingly high prevalence of very low (≤35mg/dl) and high (≥66mg/dl) HDL levels in Italian women further confirms the importance of studies on the HDL distribution in different population groups.

Lack of stereoselectivity of 8-hydroxy-2(di-N-propylamino)tetralin-mediated inhibition of forskolin-stimulated adenylyl cyclase activity in human pre- and post-synaptic brain regions.

The stereoselectivity of the serotonin1A (5-HT1A) receptor compound 8-hydroxy-2(di-N-propylamino)tetralin (8-OH-DPAT) on forskolin-stimulated adenylyl cyclase activity was investigated in membranes from human 5-HT pre-synaptic (raphe nuclei) and post-synaptic (hippocampus and prefrontal cortex) regions of autopsy brains. After sample incubation with agonists and antagonists, results showed that both the racemic mixture of 8-OH-DPAT or its (+) and (-) enantiomers behaved as full agonists in the tested brain regions. Enantiomer potency (EC50, nM) and efficacy (percentage of maximal inhibition, %) values were similar in all regions under investigation. However, some inter and intra-region variations in racemic 8-OH-DPAT potency and efficacy have been observed. In particular, the potency of racemic 8-OH-DPAT was higher in the prefrontal cortex and raphe nuclei than in the hippocampus, where it was in fact lower than either single enantiomers. Agonist effects were competitively reversed by 5-HT1A antagonists, although once again a different profile was revealed in the hippocampus. The data underscores the lack of stereospecificity of 8-OH-DPAT-mediated inhibition of adenylyl cyclase activity in either pre- or post-synaptic human brain regions. Moreover, such results have significant implication, as they support the notion that human 5-HT1A receptors might vary from one brain region to the other.

Statin intolerance in heterozygous familial hypercolesterolemia with cardiovascular disease: After PCSK-9 antibodies what else?

Background Familial hypercholesterolemia is the elective clinical condition that deserves the maximal personalisation in lipid-lowering therapy, especially in the presence of statin intolerance. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors represent a promising approach to lower low-density lipoprotein (LDL) cholesterol. Methods We enrolled 18 patients (mean age 62 ± 8 years, 72% men) affected by heterozygous familial hypercholesterolemia and cardiovascular disease, with a history of statin intolerance assigned to PCSK9 inhibitors. Six patients were also on LDL apheresis. Associated Lp(a)-hyperlipoproteinemia (defined as >60 mg/dl) was observed in two out of 18 subjects. PCSK9 inhibitor injectable monoclonal antibodies were administered, every 2 weeks, on top of patient therapy for 12 ± 4 weeks (evolocumab in 15 subjects, alirocumab in three subjects). Results After 3 months (12 ± 4 weeks) of therapy, a decrease in total cholesterol (–35%), LDL cholesterol (–51%) and Lp(a) levels (–20%) was observed. Five out of 18 patients reached LDL cholesterol levels of <70 mg/dl, seven showed LDL cholesterol values between 71 and 100 mg/dl, and six out of 18 still had LDL cholesterol levels above 100 mg/dl. Among the six patients with LDL cholesterol levels >100 mg/dl, three were already on LDL apheresis before the PCSK9 inhibitor treatment, while three were referred to LDL apheresis treatment. Adverse events were reported in two out of 18 patients on evolocumab: one presented with flu-like syndrome and the other reported episodes of mild difficulty in maintaining concentration. Conclusions PCSK9 inhibitors represent a novel therapeutic tool for patients with familial hypercholesterolemia who are intolerant to statins. However, more data are needed before cleaning up the old therapeutic armamentarium, such as LDL apheresis, which is likely to preserve its valuable role also in the new lipid-lowering era.