Synthetic high-density lipoprotein nanoparticles: Good things in small packages

Medicine has been a great beneficiary of the nanotechnology revolution. Nanotechnology involves the synthesis of functional materials with at least one size dimension between 1 and 100 nm. Advances in the field have enabled the synthesis of bio-nanoparticles that can interface with physiological systems to modulate fundamental cellular processes. One example of a diverse acting nanoparticle-based therapeutic is synthetic high-density lipoprotein (HDL) nanoparticles (NP), which have great potential for treating diseases of the ocular surface. Our group has developed a spherical HDL NP using a gold nanoparticle core. HDL NPs: (i) closely mimic the physical and chemical features of natural HDLs; (ii) contain apoA-I; (iii) bind with high-affinity to SR-B1, which is the major receptor through which HDL modulates cell cholesterol metabolism and controls the selective uptake of HDL cargo into cells; (iv) are non-toxic to cells and tissues; and (v) can be chemically engineered to display nearly any surface or core composition desired. With respect to the ocular surface, topical application of HDL NPs accelerates re-epithelization of the cornea following wounding, attenuates inflammation resulting from chemical burns and/or other stresses, and effectively delivers microRNAs with biological activity to corneal cells and tissues. HDL NPs will be the foundation of a new class of topical eye drops with great translational potential and exemplify the impact that nanoparticles can have in medicine.     

JCL roundtable: PCSK9 inhibitors in clinical practice

The roundtable this month will involve a discussion of two new drugs that have been approved by the Food and Drug Administration for the reduction of low-density lipoprotein cholesterol (LDL-C). The Food and Drug Administration approved the first of these, alirocumab as an “adjunct to diet and maximally tolerated statin therapy for the treatment of adults with heterozygous familial hypercholesterolemia or clinical atherosclerotic cardiovascular disease, who require additional lowering of LDL [low-density lipoprotein]-cholesterol.” Evolucumab has similar indications plus an indication specifically for treatment of homozygous familial hypercholesterolemia. This sets the stage for their clinical use and in this roundtable, we will discuss with two experts, the implications of these indications for the practicing physician. Dr McKenney and Dr Moriarty have had extensive experience in the conduct of clinical trials that provided the evidence of safety and efficacy of these so called PCSK9 inhibitors.     

Serum Lipoprotein(a) Level and its Clinical Significance in Patients with Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a classic autoimmune disease characterised by the production of autoreactive T cells and autoantibodies that may affect every organ system. It has long been established that there is a close association between cholesterol- rich lipoproteins (such as low-density lipoprotein-cholesterol) and cardiovascular disease in patients with SLE. In this study, we evaluated total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, VLD-cholesterol, apolipoprotein A-1, apolipoprotein B, and cholesterol-rich serum lipoprotein(a) [Lp(a)], which is accepted to be an independent risk factor for cardiovascular disease and for atherosclerosis, in 24 patients (mean age +/- SD 31.4 +/- 9.7 years, range 16-47, 22 F) with active SLE. Twenty-six healthy age- and sex-matched (mean age +/- SD 29.7 +/- 11.3 years, range 18-49 years, 22 F) subjects were included as a control group. In patients with SLE Lp(a) levels, total cholesterol, triglycerides and VLDL-cholesterol were found to be higher and HDL-cholesterol, apolipoprotein A-1 to be lower than those of controls. In conclusion, because serum Lp(a) levels are significantly higher (P<0.01) in patients with SLE, these patients have a risk of developing cardiovascular disease and atherosclerosis. Patients with SLE should be followed up with this in mind.     

脂蛋白脂酶基因S447X变异对高血压病患者肥胖与血脂关系的影响

目的　探讨脂蛋白脂酶 (LPL)基因S4 4 7X变异对高血压病 (EH)患者肥胖与血脂关系的影响。方法　选择上海社区 2周内未服用任何抗高血压药物的EH患者 983例 ,按体重指数水平分为肥胖组和体重正常组 ,应用PCR RFLP技术检测LPL S4 4 7X多态性。结果　肥胖组和体重正常组S4 4 7X基因型构成及等位基因频率差异无统计学意义 ;肥胖组甘油三酯 (TG)和Log(TG/HDL C)显著高于体重正常组 ,高密度脂蛋白胆固醇 (HDL C)水平显著低于体重正常组。按基因型分层后 ,在S4 4 7S基因型 ,肥胖组TG和Log(TG/HDL C)仍显著高于体重正常组 ,HDL C水平仍显著低于体重正常组 ;但在X4 4 7等位基因携带者 ,肥胖组和体重正常组血脂谱水平差异无统计学意义。进一步按年龄 <5 0岁和年龄≥ 5 0岁分组后 ,此种效应仅出现在高年龄组 ,且肥胖者X4 4 7等位基因携带者HDL C水平及Log(TG/HDL C)与体重正常组各基因型的相似。LPL S4 4 7X变异和肥胖对高年龄组HDL C和Log(TG/HDL C)存在交互作用 ,有统计学意义。结论　LPL S4 4 7X变异和肥胖对高年龄组HDL C和Log(TG/HDL C)具有交互作用 ,表明S4 4 7X变异调整EH肥胖者的血脂水平。     

Rendimiento diagnóstico de la secuenciación de genes de hipercolesterolemia familiar en sujetos con hipercolesterolemia primaria

Introduction and objectivesOur objective was to approximate the prevalence of mutations in candidate genes for familial hypercholesterolemia (FH) in a middle-aged Spanish population and to establish the predictive value of criteria for clinical suspicion in the detection of causative mutations.MethodsUnrelated individuals aged ≥ 18 years from the Aragon Workers’ Health Study (AWHS) with high low-density lipoprotein cholesterol (LDL-C) and clinical suspicion of FH (participants with LDL-C concentrations above the 95th percentile, participants with premature cardiovascular disease and/or participants with high LDL-C [130 mg/dL] under statin therapy), assuming that any participant with FH exhibits at leats 1 trait, were selected and the LDLR, APOB, PCSK9, APOE, STAP1 and LDLRAP1 genes were sequenced by next generation sequencing technology.ResultsOf 5400 individuals from the AWHS, 4514 had complete data on lipid levels and lipid-lowering drugs, 255 participants (5.65%) met the criteria for suspicion of FH, 24 of them (9.41%) were diagnosed with hyperlipoproteinemia(a), and 16 (6.27% of those sequenced) were found to carry causative mutations in candidate genes: 12 participants carried 11 different pathogenic LDLR alleles and 4 participants carried 1 pathogenic mutation in PCSK9. LDL-C concentrations > 220 mg/dL and LDL-C > 130 mg/dL despite statin therapy showed the strongest association with the presence of mutations (P = .011).ConclusionsOur results show that the prevalence of FH in Spain is 1:282 and suggest that the combination of high untreated LDL-C and high levels of LDL-C despite statin therapy are the best predictors of a positive FH genetic test.     

非诺贝特对兔脂肪细胞摄取及降解氧化型低密度脂蛋白及CD36表达的影响

为了解非诺贝特对高胆固醇血症兔脂肪细胞摄取及降解氧化型低密度脂蛋白的影响并探讨其可能机制 ,将 10只新西兰大白兔给予高胆固醇饲料饲养 8周后 ,随机分为高胆固醇组和非诺贝特治疗组 ,非诺贝特组在饲以高胆固醇饲料的基础上给予非诺贝特 (每天 30mg kg) ,共 4周。另设普通饮食对照组 5只。实验结束后 ,取皮下脂肪组织行脂肪细胞培养 ,放射配基法测定脂肪细胞对氧化型低密度脂蛋白的摄取及降解 ,半定量逆转录—聚合酶链反应测定脂肪细胞CD36及过氧化体增殖物激活型受体γmRNA的表达。结果发现 ,3组兔脂肪细胞摄取及降解1 2 5Ⅰ 氧化型低密度脂蛋白均呈现一浓度依赖性饱和型曲线 ,高胆固醇组脂肪细胞摄取及降解1 2 5Ⅰ 氧化型低密度脂蛋白明显低于对照组 ;非诺贝特组脂肪细胞摄取及降解1 2 5Ⅰ 氧化型低密度脂蛋白高于高胆固醇组 ,但仍低于对照组 ,3组间比较差异有显著性 (P <0 .0 5 )。逆转录聚合酶链反应发现 ,高胆固醇组过氧化体增殖物激活型受体γ及CD36mRNA表达降低 ,非诺贝特组CD36mRNA表达与对照组相似。以上提示 ,非诺贝特能改善高胆固醇血症兔脂肪细胞摄取及降解1 2 5Ⅰ 氧化型低密度脂蛋白 ,并上调CD36mRNA的表达。