Associations of High-Density Lipoprotein Functionality with Coronary Plaque Characteristics in Diabetic Patients with Coronary Artery Disease: Integrated Backscatter Intravascular Ultrasound Analysis.

High-density lipoprotein (HDL) functionality has been reported to be associated with coronary artery disease (CAD). However, little is known about the impact of HDL functionality on coronary atherosclerosis. Thirty-eight type 2 diabetic patients with CAD who underwent percutaneous coronary intervention were examined. Coronary atheroma burden and plaque composition of the culprit lesions were assessed using conventional gray-scale and integrated backscatter intravascular ultrasound. HDL-mediated cholesterol efflux capacity (HDL-CEC) and HDL antioxidant capacity, estimated as HDL inflammatory index (HII), were examined. The associations between HDL functionality and coronary plaques were analyzed using multivariate data analysis, including principal components analysis and orthogonal partial least squares (OPLS) models. Percent atheroma volume was correlated with HDL-CEC (r = 0.34, p = 0.04) but not with HII (p = 0.65). The OPLS model demonstrated that the percentage lipid volume was significantly associated with HDL functionality [coefficient (95% confidence interval); HDL-CEC: -0.26 (-0.49, -0.04); HII: 0.34 (0.08, 2.60), respectively]. HII exhibited the highest variable importance in projection score, indicating the greatest contribution. HDL functionality was associated with coronary plaque composition, a key component of plaque vulnerability. Our findings highlight the potential importance of HDL functionality for coronary plaque stabilization.

Anti-atherosclerotic effects of an improved apolipoprotein A-I mimetic peptide.

BACKGROUND: Apolipoprotein (Apo)A-I is a major protein component of high-density lipoprotein (HDL) that causes cholesterol efflux from peripheral cells through ATP-binding cassette transporter A1 (ABCA1) and the generation of HDL. Furthermore, it has a possible protective function against atherosclerotic cardiovascular disease (ASCVD). We previously developed a novel ApoA-I mimetic peptide without phospholipids (Fukuoka University ApoA-I Mimetic Peptide, FAMP). According to our previous studies, FAMP had an anti-arteriosclerotic effect. Since the required dose and reaction time of conventional FAMP were relatively large and short, respectively, we newly developed an improved FAMP (i-FAMP). METHODS AND RESULTS: We synthesized four candidate i-FAMPs, i-FAMP-D1, -D2, -D3 and -D4, and examined which i-FAMP has greater cholesterol efflux capacity than FAMP in A172 human glioblastoma cells transiently transfected with human ABCA1 cDNA. Only i-FAMP-D1 showed significantly greater cholesterol efflux capacity than conventional FAMP. i-FAMP-D1 formed stronger α-helical conformations than FAMP as assessed by circular dichroism spectra. Thus, we selected i-FAMP-D1 for further experiments. i-FAMP-D1 had a greater atheroprotective effect than FAMP in ApoE knockout mice. In addition, i-FAMP-D1 activated cholesterol efflux from macrophage to HDL more strongly than FAMP and increased cholesterol excretion from liver to feces. CONCLUSION: These results suggest that i-FAMP-D1 has a stronger anti-atherosclerotic effect than conventional FAMP.

Comparison of Two Homogeneous LDL-Cholesterol Assays Using Fresh Hypertriglyceridemic Serum and Quantitative Ultracentrifugation Fractions.

AIM: The purpose of this study was to compare two homogeneous assays of low-density lipoprotein-cholesterol (LDL-C) with a modified beta quantification reference measurement for LDL-C (BQ-LDL), fractions of chylomicron (CM), very low-density lipoprotein (VLDL) and intermediate-density lipoprotein (IDL) by quantitative ultracentrifugation in patients with hypertriglyceridemia. METHODS: Two homogeneous LDL-C assays (LDL-C(K), Kyowa Medex and LDL-C(S), Sekisui Medical) were used to measure 198 samples of fresh anonymized leftover sera with hypertriglyceridemia (≥ 150 mg/dL). Of these, 32 samples with discrepant LDL-C levels or hypertriglyceridemia (≥ 400 mg/dL) were used for further analysis. Quantitative ultracentrifugation was used to separate samples. RESULTS: The two homogeneous LDL-C assays had a strong correlation with each other for the samples from 198 patients with hypertriglyceridemia. LDL-C(K) and LDL-C(S) in 32 selected samples were strongly correlated with BQ-LDL. In both homogeneous assays, cholesterol in the CM and VLDL fractions was measured as part of the LDL-C. A weak correlation was found between cholesterol in the VLDL fraction and LDL-C using the two homogeneous assays, but no correlation was found with cholesterol in the CM fraction. Cholesterol in the IDL fraction was also measured as part of the LDL-C in both assays. CONCLUSION: Both homogeneous assays partially detected cholesterol in the chylomicron and VLDL fractions, but LDL-C measured by both homogeneous assays correlated with BQ-LDL.

Improved 68 Ga-labeling method using ethanol addition: Application to the α-helical peptide DOTA-FAMP.

We examined the 68 Ga labeling of the α-helical peptide, DOTA-FAMP, and evaluated conformational changes during radiolabeling. 68 Ga-DOTA-FAMP is a positron emission tomography probe candidate for atherosclerotic plaques. The labeling yield achieved by Zhernosekov's method (using acetone for 68 Ga purification) was compared with that achieved by the original and 2 modified Mueller's methods (using NaCl solution). Modified method I involves desalting the 68 Ga prior to labeling, and modified method II involves the inclusion of ethanol in the labeling solution. The labeling yield using Zhernosekov's method was 62% ± 5.4%. In comparison, Mueller's original method gave 8.9% ± 1.7%. Modified method I gave a slight improvement of 32% ± 2.1%. Modified method II further increased the yield to 66% ± 3.4%. Conformational changes were determined by circular dichroism spectroscopy, revealing that these differences could be attributed to conformational changes. Heat treatment affects peptide conformation, which leads to aggregation and decreases the labeling yield. Mueller's method is simpler, but harsh conditions preclude its application to biomolecules. To suppress aggregation, we included a desalting process and added ethanol in the labeling solution. These changes significantly improved the labeling yield. Before use for imaging, conformational changes of biomolecules during radiolabeling should be evaluated by circular dichroism spectroscopy to ensure the homogeneity of the labeled product.

The ApoA-I mimetic peptide FAMP promotes recovery from hindlimb ischemia through a nitric oxide (NO)-related pathway.

BACKGROUND/OBJECTIVE: HDL has various atheroprotective functions and improves endothelial function. Apolipoprotein A-I (apoA-I) is a major protein of HDL and plays a crucial role in HDL functions. We developed a novel apoA-I mimetic peptide, FAMP (Fukuoka University ApoA-I Mimetic Peptide). It is unclear whether an apoA-I mimetic peptide can promote neovascularization in vivo. Here, we investigated the effect of FAMP on endothelial nitric oxide synthase (eNOS) activation and angiogenesis in a murine hindlimb ischemia model. METHODS AND RESULTS: Intramuscular administration of FAMP significantly enhanced blood flow recovery and increased capillary density in the ischemic limb of mice fed a high-cholesterol diet (HCD). In a gait analysis, FAMP ameliorated functional recovery compared with that in the control group. FAMP significantly activated Akt, ERK, and eNOS phosphorylation in endothelial cells, and improved the migratory functions of human aortic endothelial cells (HAECs). LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), significantly inhibited the activation of eNOS by FAMP. FAMP had no beneficial effects on blood flow recovery in eNOS(-/-) mice. CONCLUSIONS: FAMP promoted recovery from hindlimb ischemia through a nitric oxide (NO)-related pathway by activation of a PI3K/Akt pathway. FAMP may become a new therapeutic agent for the future clinical treatment of critical limb ischemia (CLI).

Impact of cigarette smoking cessation on high-density lipoprotein functionality.

BACKGROUND: Smoking cessation reduces the risk of cardiovascular disease (CVD) and improves clinical outcomes in public health. We studied the effect of smoking cessation on high-density lipoprotein (HDL) functionality. METHODS AND RESULTS: We randomly treated 32 smokers with varenicline or a transdermal nicotine patch as part of a 12-week smoking cessation program (The VN-SEESAW Study). The plasma lipid profiles, plasma and HDL malondialdehyde (MDA) levels, HDL subfractions as analyzed by capillary isotachophoresis, cholesterol efflux capacity, and antiinflammatory activity of HDL were measured before and after the anti-smoking intervention. After smoking cessation, HDL-C, apoA-I levels and HDL subfractions were not significantly different from the respective baseline values. However, cholesterol efflux capacity and the HDL inflammatory index (HII) were significantly improved after smoking cessation. The changes in both parameters (%∆ cholesterol efflux capacity and ∆HII) were also significantly improved in the successful smoking cessation group compared with the unsuccessful group. The changes in cholesterol efflux capacity and HII also correlated with those in end-expiratory CO concentration and MDA in HDL, respectively. CONCLUSIONS: Our findings indicate that smoking cessation leads to improved HDL functionality, increased cholesterol efflux capacity and decreased HII, without changing HDL-C or apoA-I levels or HDL subfractions. This may be one of the mechanisms by which smoking cessation improves the risk of CVD.

Molecular diagnosis of mitochondrial respiratory chain disorders in Japan: focusing on mitochondrial DNA depletion syndrome.

BACKGROUND: Although mitochondrial respiratory chain disorders (MRCD) are one of the most common congenital metabolic diseases, there is no cumulative data on enzymatic diagnosis and clinical manifestation for MRCD in Japan and Asia. METHODS: We evaluated 675 Japanese patients having profound lactic acidemia, or patients having symptoms or signs of multiple-organ origin simultaneously without lactic acidemia on respiratory chain enzyme activity assay and blue native polyacrylamide gel electrophoresis. Quantitative polymerase chain reaction was used to diagnose mitochondrial DNA depletion syndrome (MTDPS). Mutation analysis of several genes responsible for MTDPS was also performed. RESULTS: A total of 232 patients were diagnosed with a probable or definite MRCD. MRCD are common, afflicting one in every several thousand people in Japan. More than one in 10 of the patients diagnosed lacked lactic acidemia. A subsequent analysis of the causative genes of MTDPS identified novel mutations in six of the patients. A 335 bp deletion in deoxyguanosine kinase (DGUOK; g.11692_12026del335 (p.A48fsX90)) was noted in two unrelated families, and may therefore be a common mutation in Japanese people. The proportion of all patients with MTDPS, and particularly those with recessive DNA polymerase γ (POLG) mutations, appears to be lower in Japan than in other studies. This is most likely due to the relatively high prevalence of ancient European POLG mutations in Caucasian populations. No other significant differences were identified in a comparison of the enzymatic diagnoses, disease classifications or prognoses in Japanese and Caucasian patients with MRCD. CONCLUSION: MTDPS and other MRCD are common, but serious, diseases that occur across all races.

Improved survival rate after myocardial infarction using an inducible cholesterol efflux (iCE) peptide: FAMP.

BACKGROUND: There have been no previous reports that apolipoprotein (apo) A-I mimetic peptide improves survival rate after myocardial infarction (MI). METHOD AND RESULTS: Male C57Bl/6J mice were subjected to left coronary artery permanent ligation as a model of MI. We synthesized a novel 24-amino acid apoA-I mimetic peptide-type5 (FAMP5), which potently removes cholesterol via specific ATP-binding cassette transporter A1 (ABCA1). FAMP5 was associated with a significantly improved survival rate by protecting against cardiac rupture compared to the control. mRNA levels for eNOS, Gata-4, CTGF and ANP were significantly increased in the hearts of the FAMP5-treated group, while that for MCP-1 decreased. CONCLUSION: This is the first report that high-density lipoprotein (HDL) therapy with FAMP5 improved the survival rate after MI.

Therapeutic approaches to the regulation of metabolism of high-density lipoprotein. Novel HDL-directed pharmacological intervention and exercise.

High-density lipoprotein (HDL) and low-density lipoprotein (LDL) particles transport cholesterol in plasma and play an important role in cellular cholesterol homeostasis, which influences cell function. The risk of coronary artery disease (CAD) associated with high levels of LDL-cholesterol (LDL-C) can be reduced by treatment with statins, which reduce LDL-C levels by inhibiting cellular cholesterol synthesis. However, patients who are treated with high doses of statins, especially secondary CAD prevention, regardless of their resulting LDL-C levels, are still at high risk of CAD. Therefore, there has been growing interest in HDL-directed therapies. Inhibitors of cholesteryl ester transfer protein (CETP) substantially increase HDL-C levels (by 31-138%). However, it is still unclear whether or not CETP inhibitors can reduce the risk of CAD associated with low HDL-C levels, while reconstituted HDL or apolipoprotein A-I mimetic peptides increase the functionality of HDL. Low levels of HDL-C are often complicated with metabolic disorders, including hypertriglyceridemia, metabolic syndrome, and type 2 diabetes mellitus, and lifestyle changes are effective for correcting these conditions. Physical activity and exercise training increase HDL-C levels, especially HDL2-C levels, by multiple mechanisms. Therefore, although using HDL-directed therapies that increase HDL-C levels and/or improve the function of HDL is a reasonable approach for reducing the residual risk of CAD as a complement to LDL-C-lowering therapy, lifestyle modifications including exercise to improve metabolic disorders should be considered as the first option.

FAMP, a novel apoA-I mimetic peptide, suppresses aortic plaque formation through promotion of biological HDL function in ApoE-deficient mice.

BACKGROUND: Apolipoprotein (apo) A-I is a major high-density lipoprotein (HDL) protein that causes cholesterol efflux from peripheral cells through the ATP-binding cassette transporter A1 (ABCA1), thus generating HDL and reversing the macrophage foam cell phenotype. Pre-ß1 HDL is the smallest subfraction of HDL, which is believed to represent newly formed HDL, and it is the most active acceptor of free cholesterol. Furthermore it has a possible protective function against cardiovascular disease (CVD). We developed a novel apoA-I mimetic peptide without phospholipids (Fukuoka University ApoA-I Mimetic Peptide, FAMP). METHODS AND RESULTS: FAMP type 5 (FAMP5) had a high capacity for cholesterol efflux from A172 cells and mouse and human macrophages in vitro, and the efflux was mainly dependent on ABCA1 transporter. Incubation of FAMP5 with human HDL or whole plasma generated small HDL particles, and charged apoA-I-rich particles migrated as pre-ß HDL on agarose gel electrophoresis. Sixteen weeks of treatment with FAMP5 significantly suppressed aortic plaque formation (scrambled FAMP, 31.3 ± 8.9% versus high-dose FAMP5, 16.2 ± 5.0%; P<0.01) and plasma C-reactive protein and monocyte chemoattractant protein-1 in apoE-deficient mice fed a high-fat diet. In addition, it significantly enhanced HDL-mediated cholesterol efflux capacity from the mice. CONCLUSIONS: A newly developed apoA-I mimetic peptide, FAMP, has an antiatherosclerotic effect through the enhancement of the biological function of HDL. FAMP may have significant atheroprotective potential and prove to be a new therapeutic tool for CVD.

Novel molecular imaging of atherosclerosis with gallium-68-labeled apolipoprotein A-I mimetic peptide and positron emission tomography.

BACKGROUND: High-density lipoprotein (HDL) plays a major role in reverse cholesterol transport. Many researchers have been working to enhance the biochemical function of HDL for use in therapy. Although HDL therapy using injections of apolipoprotein (apo)-A-I mimetics, apo A-I Milano or full-length apo A-I is dramatically effective, it is still unclear whether apo A-I or apo A-I mimetics actually enter atherosclerotic plaque and remove cholesterol from the lipid burden. We synthesized a novel 24-amino acid apo A-I mimetic peptide (known as FAMP) that potently removes cholesterol via specific ATP-binding cassette transporter A1. We then investigated the potential of FAMP to image developing plaque lesions in vivo. METHODS AND RESULTS: FAMP was modified with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and radiolabeled with gallium-68 ((68)Ga) for noninvasive positron emission tomography (PET) in an animal model (familial hypercholesterolemic myocardial infarction-prone rabbits: WHHL-MI) with atherosclerotic lesions. The (68)Ga-DOTA-FAMP was dramatically taken up by atherosclerotic tissues in the blood vessels and aorta of WHHL-MI rabbits, but not the control rabbits. CONCLUSIONS: An apo A-I mimetic peptide with (68)Ga-DOTA is a promising candidate diagnostic tracer for PET imaging of the atherosclerotic lipid burden and may contribute to the development of a tool for the diagnosis of plaque with PET.

Reactivity of direct assays for low-density lipoprotein (LDL) cholesterol toward charge-modified LDL in hypercholesterolemia.

BACKGROUND: The aim of the present study was to compare 2 direct measurements for low-density lipoprotein cholesterol (LDL-C) with the Friedewald calculation (LDL-C [F]) in serum and their relationship with size-and charge-based LDL subfractions in serum ultracentrifugation fractions in patients with hypercholesterolemia (HC). METHODS AND RESULTS: Serum samples from 283 HC patients who participated in a statin trial (the PATROL trial) were analyzed. Homogeneous assays for LDL-C were performed using reagents from Sekisui Medical (LDL-C [Se]) and Kyowa Medex (LDL-C [Ky]). Charge-based LDL subfractions were analyzed by capillary isotachophoresis (cITP). In whole serum in HC patients at baseline, LDL-C (Se) and LDL-C (Ky) negatively and positively deviated, respectively, from LDL-C (F). The negative deviation of LDL-C (Se) from LDL-C (F) increased with increasing LDL-C, while the positive deviation of LDL-C (Ky) from LDL-C (F) was positively correlated with charge-modified LDL (cmLDL) as analyzed by cITP. In serum d>1.006 g/ml and >1.040 g/ml fractions (LDL and small, dense LDL fractions, respectively), the deviation of LDL-C (Ky) from LDL-C (Se) was positively correlated with LDL-apoB (the number of LDL particles) and cmLDL. CONCLUSIONS: The 2 homogenous assays for LDL-C differed with regard to reactivity toward LDL particles and cmLDL in patients with HC. Direct measurement of LDL-C that reflects modified LDL, could be a better marker for the risk of coronary heart disease.

Secoiridoid glucosides from Strychnos spinosa.

Three new secoiridoid glucosides, stryspinoside (1) and strychosides A (2) and B (3), were isolated, together with 23 known compounds, from the dried branches of Strychnos spinosa. The structures of the new compounds were determined by spectroscopic means.