Search

• In FD, PCSK9 mAbs in particular reduce smaller and cholesterol-rich lipoproteins. • PCSK9 mAbs do not affect CM metabolism. • PCSK9 mAbs probably achieve their effects by increased hepatic clearance. Proprotein convertase subtilisin kexin type 9 (PCSK9) monoclonal antibodies (mAbs) reduce fasting and post fat load cholesterol in non-HDL and intermediate density lipoprotein (IDL) in familial dysbetalipoproteinemia (FD). However, the effect of PCSK9 mAbs on the distribution and composition of atherogenic lipoproteins in patients with FD is unknown. To evaluate the effect of the PCSK9 mAb evolocumab added to standard lipid-lowering therapy in patients with FD on fasting and post fat load lipoprotein distribution and composition. Randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. Patients received an oral fat load at the start and end of each treatment period. Apolipoproteins (apo) were measured with ultracentrifugation, gradient gel electrophoresis, retinyl palmitate and SDS-PAGE. PCSK9 mAbs significantly reduced particle number of all atherogenic lipoproteins, with a stronger effect on smaller lipoproteins than on larger lipoproteins (e.g. IDL-apoB 49%, 95%confidence interval (CI) 41–59 and very low-density lipoprotein (VLDL)-apoB 33%, 95%CI 16-50). Furthermore, PCSK9 mAbs lowered cholesterol more than triglyceride (TG) in VLDL, IDL and low-density lipoprotein (LDL) (e.g. VLDL-C 48%, 95%CI 29–63%; and VLDL-TG 20%, 95%CI 6.3–41%). PCSK9 mAbs did not affect the post fat load response of chylomicrons. PCSK9 mAbs added to standard lipid-lowering therapy in FD patients significantly reduced lipoprotein particle number, in particular the smaller and more cholesterol-rich lipoproteins (i.e. IDL and LDL). PCSK9 mAbs did not affect chylomicron metabolism. It seems likely that the observed effects are achieved by increased hepatic lipoprotein clearance, but the specific working mechanism of PCSK9 mAbs in FD patients remains to be elucidated. [Display omitted] [ABSTRACT FROM AUTHOR]

• In familial dysbetalipoproteinemia (FD), evolocumab reduced non-HDL-C by 49%. • Non-HDL-C treatment goals were achieved by 89% of patients using evolocumab. • Evolocumab likely results in CVD reduction in FD. Familial dysbetalipoproteinemia (FD) is the second most common monogenic lipid disorder (prevalence 1 in 850-3500), characterized by postprandial remnant accumulation and associated with increased cardiovascular disease (CVD) risk. Many FD patients do not achieve non-HDL-C treatment goals, indicating the need for additional lipid-lowering treatment options. To evaluate the effect of the PCSK9 monoclonal antibody evolocumab added to standard lipid-lowering therapy on fasting and post fat load lipids and lipoproteins in patients with FD. A randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. At the start and end of each treatment period patients received an oral fat load. The primary endpoint was the 8-hour post fat load non-HDL-C area under the curve (AUC). Secondary endpoints included fasting and post fat load lipids and lipoproteins. In total, 28 patients completed the study. Mean age was 62±9 years and 93% had an Ɛ2Ɛ2 genotype. Evolocumab reduced the 8-hour post fat load non-HDL-C AUC with 49% (95%CI 42-55) and apolipoprotein B (apoB) AUC with 47% (95%CI 41-53). Other fasting and absolute post fat load lipids and lipoproteins including triglycerides and remnant-cholesterol were also significantly reduced by evolocumab. However, evolocumab did not have significant effects on the rise above fasting levels that occurred after consumption of the oral fat load. Evolocumab added to standard lipid-lowering therapy significantly reduced fasting and absolute post fat load concentrations of non-HDL-C, apoB and other atherogenic lipids and lipoproteins in FD patients. The clinically significant decrease in lipids and lipoproteins can be expected to translate into a reduction in CVD risk in these high-risk patients. [Display omitted] [ABSTRACT FROM AUTHOR]

There is a lack of information on the health care of familial hypercholesterolemia (FH). The objective of this study was to compare the health care of FH in countries of the Asia-Pacific region and Southern Hemisphere. A series of questionnaires were completed by key opinion leaders from selected specialist centers in 12 countries concerning aspects of the care of FH, including screening, diagnosis, risk assessment, treatment, teaching/training, and research; the United Kingdom (UK) was used as the international benchmark. The estimated percentage of patients diagnosed with the condition was low (overall <3%) in all countries, compared with ∼15% in the UK. Underdetection of FH was associated with government expenditure on health care (ϰ = 0.667, P <.05). Opportunistic and systematic screening methods, and the Dutch Lipid Clinic Network criteria were most commonly used to detect FH; genetic testing was infrequently used. Noninvasive imaging of coronary calcium and/or carotid plaques was underutilized in risk assessment. Patients with FH were generally not adequately treated, with <30% of patients achieving guideline recommended low-density lipoprotein cholesterol targets on conventional therapies. Treatment gaps included suboptimal availability and use of lipoprotein apheresis and proprotein convertase subtilsin-kexin type 9 inhibitors. A deficit of FH registries, training programs, and publications were identified in less economically developed countries. The demonstration of cost-effectiveness for cascade screening, genetic testing, and specialized treatments were significantly associated with the availability of subsidies from the health care system (ϰ = 0.571–0.800, P <.05). We identified important gaps across the continuum of care for FH, particularly in less economically developed countries. Wider implementation of primary and pediatric care, telehealth services, patient support groups, education/training programs, research activities, and health technology assessments are needed to improve the care of patients with FH in these countries. • We identified important gaps across the continuum of care for familial hypercholesterolemia (FH) in 12 countries. • Estimated percentage of patients diagnosed with FH was low (overall <3%). • Diagnosis of FH was associated with government expenditure on health care. • Use of lipoprotein apheresis and PCSK9 inhibitors were limited in most countries. • Availability of subsidy from the health care system is important for the care of FH. [ABSTRACT FROM AUTHOR]

Tendon xanthoma are most commonly associated with Familial Hypercholesterolemia, but the differential diagnosis includes sitosterolemia and cerebrotendinous xanthomatosis (CTX). The case presented here is of a 48-year old male with large tendon xanthomas attributable to CTX. CTX is a rare, recessive disorder caused by mutations in the CYP27A1 gene. The resultant defect in bile acid synthesis leads to cholestanol deposition in different tissues in the body, including tendons. CTX is associated with neurologic symptoms and a reduced life expectancy. Treatment consists of bile acid supplementation in combination with a statin. When patients present with tendon xanthomas and FH is ruled out, clinicians should consider CTX as a possible diagnosis. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a complex process involving the build-up of arterial plaque incorporating low-density lipoprotein cholesterol (LDL-C) and an inflammatory response. Lowering plasma LDL-C confers cardiovascular benefit for patients with hypercholesterolemia resulting from genetic and/or lifestyle factors. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of LDL-C metabolism. Secreted from liver cells, circulating PCSK9 binds to the LDL receptor and is subsequently internalized with the receptor, thereby promoting its cellular degradation. As a result, PCSK9 gain-of-function mutations are causatively associated with familial hypercholesterolemia, whereas PCSK9 loss-of-function mutations are associated with very low LDL-C levels and a reduced cardiovascular risk. Preventing PCSK9-mediated LDL receptor degradation with monoclonal antibodies is a novel strategy to further lower LDL-C, especially in patients with severe forms of hypercholesterolemia with elevated LDL-C despite maximal conventional treatment and/or in those intolerant to conventional therapies. Here, the safety and efficacy of these novel therapeutic agents targeting PCSK9 will be discussed with respect to recent clinical trials targeting this molecule, as well as inherited hypolipidemias and animal models that confer very low LDL-C because of PCSK9 deficiency. [ABSTRACT FROM AUTHOR]

Background: Dysbetalipoproteinemia is an uncommon genetic disorder characterized by accumulation of plasma remnant lipoproteins, severe mixed dyslipidemia, elevated apolipoprotein E levels, accelerated atherosclerosis, and premature cardiovascular disease. Objective: To evaluate the efficacy and safety of rosuvastatin in patients with dysbetalipoproteinemia. Methods: Following a 6-week washout, 32 patients with dysbetalipoproteinemia received rosuvastatin 10 mg, rosuvastatin 20 mg, and pravastatin 40 mg, each for 6 weeks in a randomized, double-blind, three-way crossover design. Patients subsequently entered an 18-week open-label phase in which the rosuvastatin dosage could be increased from 20 mg to a maximum of 40 mg at 6 weekly intervals to reach National Cholesterol Education Program goals for non–high-density lipoprotein cholesterol (non–HDL-C) and optimal triglyceride (TG). Fibrates (except gemfibrozil) could be added if patients were not at goal on rosuvastatin 40 mg. The primary efficacy variable was percent change from baseline in non–HDL-C during the double-blind phase. The prespecified efficacy criterion was for the 95% confidence interval (CI) of non–HDL-C to lie entirely below −25% for any rosuvastatin dose. Results: Following drug washout, median total cholesterol was 8.86 mmol/L, non–HDL-C 7.61 mmol/L, and TG 5.69 mmol/L. After 6-week treatment, median change in non–HDL-C was −48.2% (95% CI −56.7% to −45.6%) for rosuvastatin 10 mg, −56.4% (95% CI −61.4% to −48.5%) for rosuvastatin 20 mg, and −35.1% (95% CI −41.6% to −29.6%) for pravastatin 40 mg. Rosuvastatin increased HDL-C and apolipoprotein A-I and substantially reduced total, very low-, intermediate-, and low-density lipoprotein cholesterol and TG, and corresponding apolipoproteins. Efficacy was maintained in the open-label phase, with reduction in non–HDL-C of −61.5%, −62.8% and −65.8% at weeks 24, 30 and 36, respectively. All treatments were well tolerated. Conclusion: Rosuvastatin 10 and 20 mg favorably modify the dyslipidemia of patients with dysbetalipoproteinemia. [Copyright &y& Elsevier]

Abstract: This study assessed the efficacy of rosuvastatin for reducing plasma low-density lipoprotein (LDL) cholesterol after 18 weeks of open-label, forced titration in patients with homozygous familial hypercholesterolaemia (hoFH) and compared the efficacy of rosuvastatin 80mg and atorvastatin 80mg. Forty-four patients aged 8–63 years (body mass ≥32kg) entered the study; 4 had portacaval shunts and 11 were receiving plasmapheresis. Patients sequentially received rosuvastatin 20, 40 and 80mg/day for 6 weeks. Patients remaining in the trial after 18 weeks received double-blind, randomised crossover treatment with rosuvastatin 80mg/day and atorvastatin 80mg/day for 6 weeks each. After 18 weeks, mean (S.D.)% reduction from baseline in LDL cholesterol was 22 (21)% overall and by 26 (15)% in 29 patients who neither had a portacaval shunt nor were receiving plasmapheresis. Seventy-two percent of the patients had ≥15% reductions in LDL cholesterol and were considered responders and included patients who had portacaval shunts or were receiving plasmapheresis. Mean LDL reductions from baseline after crossover treatment (n =21) with rosuvastatin 80mg and atorvastatin 80mg were 19 and 18%, respectively. All treatments were well tolerated. Rosuvastatin may have therapeutic value in the management of hoFH. [Copyright &y& Elsevier]

Abstract: We analysed the Proprotein Convertase Subtilisin Kexin type 9 (PCSK9) exons and intronic junctions of 71 patients with familial hypercholesterolemia (FH) in whom LDL receptor (LDLR) or apolipoprotein B100 mutations were excluded. The previously reported S127R and R237W mutations were found in South African families, whereas new missense mutations D129G and A168E were found in families from New Zealand. Only, the S127R and D129G mutations modify a highly conserved residue and segregate with the FH phenotype. We overexpressed those mutants in hepatoma cells and found that both S127R and D129G have reduced autocatalytic activity compared with wild-type PCSK9, whereas the A168E mutant is processed normally. The S127R and D129G mutants were not secreted from cells, unlike the A168E mutant and wild-type PCSK9. By immunoblot, we showed that the expression of the LDLR was reduced by 40% in cells overexpressing wild-type or A168E PCSK9 and further reduced by 30% when the S127R or D129G mutants were used. Paralleling the LDLR levels, LDL cellular binding decreased by 25% upon wild-type PCSK9 or A168E overexpression, and by 45% with both S127R and D129G mutants. Our study therefore indicates that PCSK9 mediated inhibition of the LDLR does not require PCSK9 autocatalytic cleavage or secretion, suggesting that PCSK9 may also function intracellularly. [Copyright &y& Elsevier]

Abstract: Objective: Missense mutations in the proprotein convertase subtilisin/kexin type 9 gene (PCSK9) can cause familial hypercholesterolemia. However, two nonsense variants of PCSK9, Y142X and C679X, found in ∼2% of black American subjects, are associated with a 28% reduction in mean low density lipoprotein (LDL)–cholesterol. We sought to determine the frequency and effect of these nonsense variants in an African population. Methods and results: PCSK9 genotypes were determined in 653 black African women attending two antenatal clinics in Zimbabwe. C679X occurred in 3.7% of subjects and was associated with a 27% reduction in LDL–cholesterol (1.6±0.3mmol/L versus 2.2±0.7mmol/L in non-carriers). We did not observe the Y142X variant. Conclusions: Our results show that the PCSK9 C679X variant has a marked cholesterol-lowering effect. [Copyright &y& Elsevier]

Background: An open-label, randomized, multinational, parallel-group trial compared the short-term (6-week) renal effects of rosuvastatin 40 mg and simvastatin 80 mg in patients with hypercholesterolemia. Most patients (93%) then entered an optional open-label extension (OLE) to assess long-term (up to 72 weeks) renal effects of rosuvastatin. Methods: After dietary lead-in, 626 patients were randomized to rosuvastatin or simvastatin for 6 weeks, followed by an optional, single-arm OLE to assess longer-term effects of rosuvastatin on renal function, safety, and efficacy. Results: The primary endpoint, a shift in urine dipstick protein from “none” or “trace” at baseline to “+” or greater in the first 4 weeks, was observed in 6.4% of patients receiving rosuvastatin and 1.0% of those receiving simvastatin. The incidence of shifts in urine dipstick protein at any time from none or trace to “++” or greater (proteinuria), was low (1.3%, rosuvastatin; 0.3%, simvastatin), transient and urine protein was predominantly of tubular or mixed origin. More patients achieved Third Adult Treatment Panel of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP ATP III) low-density lipoprotein cholesterol (LDL-C) goals with rosuvastatin vs simvastatin after 6 weeks (77.9% vs 60.4%). Results from the OLE (median rosuvastatin treatment = 47 weeks) were consistent with the randomized period. Mean serum creatinine levels remained stable, indicating no decline in renal function. Conclusion: A small proportion of patients treated with rosuvastatin 40 mg may experience a transient proteinuria, predominantly of tubular origin and not associated with declining renal function. Rosuvastatin modified lipid levels effectively, enabled more patients to attain LDL-C goals, and demonstrated a favorable benefit/risk profile. [Copyright &y& Elsevier]

This study assessed the efficacy and safety of avasimibe (CI-1011), an inhibitor of acyl coenzyme A-cholesterol acyltransferase (ACAT) in subjects with homozygous familial hypercholesterolemia (HoFH). Twenty seven subjects were enrolled in a double-blind, randomized, 3-sequence crossover trial of atorvastatin 80 mg QD, avasimibe 750 mg QD, and the combined treatment of atorvastatin 80 mg QD and avasimibe 750 mg QD after a washout period of 4 weeks. Each treatment period was administered over 6 weeks for a total of 18 weeks. There were no significant lipid changes resulting from the administration of avasimibe monotherapy. Avasimibe in combination with atorvastatin resulted in a significantly better reduction of total cholesterol (TC) as compared to atorvastatin alone (−22% versus −18%) (P<0.05). All other lipid changes were not statistically significant for combination therapy compared to atorvastatin monotherapy, however there were greater reductions in triglycerides (TG) (−24% versus −13%), low-density lipoprotein cholesterol (LDL-C) (−23% versus −19%), very low-density lipoprotein cholesterol (VLDL-C) (−24% versus −13%) and high-density lipoprotein cholesterol (HDL-C) (−11% versus −6%). Avasimibe may modestly enhance the lipid-reducing effect of atorvastatin by further inhibiting the production of intracellular cholesterol through mechanisms that appear to be compatible in this population. [Copyright &y& Elsevier]

High density lipoprotein cholesterol (HDL-C) concentration correlates inversely with atherosclerotic cardiovascular disease (ASCVD) risk and is included in risk calculations. Endothelial lipase (EL) is a phospholipase that remodels HDL. Deficiency of EL due to mutations in its gene, LIPG , is associated with hyperalphalipoproteinemia. The effects of EL on HDL function and ASCVD risk remain poorly understood. To determine whether hyperalphalipoproteinemia due to EL deficiency is protective against ASCVD. We identified LIPG variants amongst patients with severe hyperalphalipoproteinemia (HDL-C >2.5 mmol/L) attending a referral lipid clinic in the Western Cape Province of South Africa. We analysed the clinical and biochemical phenotypes amongst primary hyperalphalipoproteinemia cases (males HDL-C >1.6 mmol/L; females HDL-C >1.8 mmol/L) due to LIPG variants, and the distribution of variants in normal and hyperalphalipoproteinemia ranges of HDL-C. 1007 patients with HDL-C concentration ranging from 1.2 to 4.5 mmol/L were included. Seventeen females had primary hyperalphalipoproteinemia. Vascular disease was prominent, but not associated with HDL-C concentration, LDL-C concentration or carotid artery intima media thickness. Two novel and three known LIPG variants were identified in severe hyperalphalipoproteinemia. Four additional variants were identified in the extended cohort. Two common variants appeared normally distributed across the HDL-C concentration range, while six less-common variants were found only at higher HDL-C concentrations. One rare variant had a moderate effect. Hyperalphalipoproteinemia due to LIPG variants is commoner in females and may not protect against ASCVD. Use of current risk calculations may be inappropriate in patients with hyperalphalipoproteinemia due to EL deficiency. Our study cautions targeting EL to reduce risk. • Seven known and two novel variants in LIPG identified in a South African cohort. • Variants in LIPG variably impact HDL-C concentration. • High HDL-C due to endothelial lipase dysfunction may not be atheroprotective. • Coronary artery intima media thickness not associated with cardiovascular disease. [ABSTRACT FROM AUTHOR]

Familial dysbetalipoproteinemia (FD) is a genetic disorder of lipoprotein metabolism associated with an increased risk for premature cardiovascular disease. In about 10% of the cases, FD is caused by autosomal dominant mutations in the apolipoprotein E gene ( APOE ). This review article provides a pathophysiological framework for autosomal dominant FD (ADFD) and discusses diagnostic challenges and therapeutic options. The clinical presentation and diagnostic work-up of ADFD are illustrated by two cases: a male with premature coronary artery disease and a p.K164Q mutation in APOE and a female with mixed hyperlipidemia and a p.R154H mutation in APOE . ADFD is characterized by a fasting and postprandial mixed hyperlipidemia due to increased remnants. Remnants are hepatically cleared by the low-density lipoprotein receptor and the heparan sulfate proteoglycan receptor (HSPG-R). Development of FD is associated with secondary factors like insulin resistance that lead to HSPG-R degradation through sulfatase 2 activation. Diagnostic challenges in ADFD are related to the clinical presentation; lipid phenotype; dominant inheritance pattern; genotyping; and possible misdiagnosis as familial hypercholesterolemia. FD patients respond well to lifestyle changes and to combination therapy with statins and fibrates. To conclude, diagnosing ADFD is important to adequately treat patients and their family members. In patients presenting with mixed hyperlipidemia, (autosomal dominant) FD should be considered as part of the diagnostic work up. [ABSTRACT FROM AUTHOR]

Objective: Evaluate the efficacy and safety of colesevelam hydrochloride in children with heterozygous familial hypercholesterolemia (heFH). Study design: This was a randomized, double-blind, 41-site study in 194 children aged 10 to 17 years (inclusive) with heFH (statin-naïve or on a stable statin regimen). After a 4-week stabilization period (period I), subjects were randomized 1:1:1 to placebo, colesevelam 1.875 g/d, or colesevelam 3.75 g/d for 8 weeks (period II). All then received open-label colesevelam 3.75 g/d for 18 weeks (period III), with follow-up 2 weeks later. The primary endpoint was percent change in low-density lipoprotein (LDL)-cholesterol from baseline to week 8. Secondary endpoints included percent change in other lipoprotein variables, including non-high-density lipoprotein (non-HDL)-cholesterol. Adverse events were also evaluated. Results: At week 8, a significant difference from baseline in LDL-cholesterol was reported with colesevelam 1.875 g/d (−6.3%; P = .031) and colesevelam 3.75 g/d (−12.5%; P < .001) compared with placebo. Significant treatment effects were also reported for total cholesterol (−7.4%), non-HDL-cholesterol (−10.9%), HDL-cholesterol (+6.1%), apolipoprotein A-I (+6.9%), and apolipoprotein B (−8.3%) and a nonsignificant effect for triglycerides (+5.1%) with colesevelam 3.75 g/d compared with placebo at week 8. These treatment effects were maintained during period III. Conclusions: Colesevelam significantly lowered LDL-cholesterol levels in children with heFH. [Copyright &y& Elsevier]

Objectives: Do elevated proprotein convertase subtilisin/kexin type 9 (PCSK9) levels constitute an even greater risk for patients who already have reduced low-density lipoprotein receptor (LDLR) levels, such as those with heterozygous familial hypercholesterolemia (HeFH)? Background: As a circulating inhibitor of LDLR, PCSK9 is an attractive target for lowering LDL-cholesterol (LDL-C) levels. Methods: Circulating PCSK9 levels were measured by enzyme-linked immunosorbent assay in nontreated patients with HeFH carrying a D206E (n = 237), V408M (n = 117), or D154N (n = 38) LDLR missense mutation and in normolipidemic controls (n = 152). Skin fibroblasts and lymphocytes were isolated from a subset of patients and grown in 0.5% serum and mevastatin with increasing amounts of recombinant PCSK9. LDLR abundance at the cell surface was determined by flow cytometry. Results: PCSK9 reduced LDLR expression in a dose-dependent manner in control and FH fibroblasts to similar extents, by up to 77 ± 8% and 82 ± 7%, respectively. Likewise, PCSK9 reduced LDLR abundance by 39 ± 8% in nonfamilial hypercholesterolemia (non-FH) and by 45 ± 10% in HeFH lymphocytes, irrespective of their LDLR mutation status. We found positive correlations of the same magnitude between PCSK9 and LDL-C levels in controls (beta = 0.22; p = 0.0003), D206E (beta = 0.20; p = 0.0002), V408M (beta = 0.24; p = 0.0002), and D154N (beta = 0.25; p = 0.048) patients with HeFH. The strengths of these associations were all similar. Conclusions: Elevated PCSK9 levels are equally detrimental for patients with HeFH or non-FH: a 100-ng/ml increase in PCSK9 will lead to an increase in LDL-C of 0.20 to 0.25 mmol/l in controls and HeFH alike, irrespective of their LDLR mutation. This explains why patients with non-FH or HeFH respond equally well to monoclonal antibodies targeting PCSK9. [ABSTRACT FROM AUTHOR]