Homozygous familial hypercholesterolemia: Long term clinical course and plasma exchange therapy for two individual patients and review of the literature

Perioperative Management and Clinical Outcomes of Liver Transplantation for Children with Homozygous Familial Hypercholesterolemia

Background and Objectives: Liver transplantation (LT) has been accepted as a life-saving option as a last resort for children with homozygous familial hypercholesterolemia (HoFH). Perioperative management of LT for HoFH poses extra challenges for clinicians largely due to premature atherosclerotic cardiovascular diseases (ASCVDs). We aimed to analyze our data of pediatric LT recipients with HoFH, with special attention paid to perioperative management and clinical outcomes. Materials and Methods: After obtaining approval from the local ethics committee, the clinical data of pediatric patients with HoFH who underwent LT at our institution between January 2014 and February 2021 were retrospectively studied. Results: Six pediatric LT recipients with HoFH were included in the analysis. Although ASCVDs were common before LT, all children with HoFH survived the perioperative period without in-hospital mortality. However, one patient experienced acute myocardial infarction two months following LT and was successfully treated with medical interventions. Post-LT metabolic improvement was shown by declines in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in the early post-LT period (for TC: 14.7 ± 3.2 mmol/L vs. 5.5 ± 1.8 mmol/L, p < 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 3.6 ± 1.2 mmol/L, p < 0.001, respectively) and at the last follow-up (for TC: 14.7 ± 3.2 mmol/L vs. 4.5 ± 0.9 mmol/L, p = 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 2.8 ± 0.6 mmol/L, p = 0.001, respectively). Dietary restrictions could be lifted after LT. However, three patients required restarting lipid-lowering therapy after LT due to suboptimal LDL-C levels and progression of ASCVDs. Conclusions: Our data suggest that LT can be a safe and feasible therapeutic option for well-selected patients with HoFH, offering relaxed dietary restrictions and remarkable reductions in LDL-C levels. However, concerns remain regarding progression of ASCVDs after LT.

Vascular access for lipid apheresis: a challenge in young children with homozygous familial hypercholesterolemia

Background

Homozygous familial hypercholesterolemia (hoFH) is a rare genetic disorder leading to extremely increased LDL-cholesterol (LDL-C), resulting in high cardiovascular risk in early childhood. Lipid apheresis (LA) is an effective treatment and should be started as early as possible to prevent premature cardiovascular events. As peripheral punctures in children can be challenging due to small vessels and anxiety, this study aimed to evaluate feasibility and safety of central venous catheters (CVCs) as vascular access for LA in young children with hoFH.

Methods

Retrospective analysis (2016-2019) on four children with hoFH aged 3-5 years, performing weekly or biweekly LA with a CVC.

Results

LDL-C decreased by> 60%. In three children, the use of a permanent CVC for 698, 595, and 411 days, respectively, avoided difficult peripheral access, without the occurrence of occlusion or thrombosis. Unfortunately, one child had recurrent CVC-related infections and needed an arteriovenous fistula from the age of 5. Although the mean dwell time per catheter was 212 days, there were, as expected, severe side effects of early catheter infections with sepsis and accidental self-removal. Starting LA at an early age improved or stabilized carotid intima-media thickness (IMT) in three children. However, IMT did increase in one child caused by intolerance to peripheral punctures and LA interruption.

Conclusions

Permanent CVCs are a viable temporary access choice for LA in young children with hoFH until peripheral venipuncture is practicable. The risk of CVC-related infections needs to be taken into account.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03192-7.

Treatment of homozygous familial hypercholesterolaemia in paediatric patients: A monocentric experience

Background

Homozygous familial hypercholesterolaemia is a rare life-threatening disease characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) concentrations and accelerated atherosclerosis. The presence of double gene defects in the LDL-Receptor, either the same defect (homozygous) or two different LDL-raising mutations (compound heterozygotes) or other variants, identify the homozygous phenotype (HopFH). Apheresis is a procedure in which plasma is separated from red blood cells before the physical removal of LDL-C or the LDL-C is directly removed from whole blood. It is currently the treatment of choice for patients with HopFH whose LDL-C levels are not able to be reduced to target levels with conventional lipid-lowering drug therapy.

Design

The aim of this study is to report a cohort of six paediatric patients and to evaluate the long term efficacy of combined medical therapy and LDL-apheresis on LDL-C reduction.

Methods

We collected data from six children with confirmed diagnosis of HopFH (two females and four males; age range at diagnosis 3–8 years, mean 6 ± 1 years) from a single clinical hospital in Italy from 2007 to 2017.

Results

Clinical manifestations and outcomes may greatly vary in children with HopFH. Medical therapy and LDL-apheresis for the severe form should be started promptly in order to prevent cardiovascular disease.

Conclusions

Lipoprotein apheresis is a very important tool in managing patients with HopFH at high risk of cardiovascular disease. Based on our experience and the literature data, the method is feasible in very young children, efficient regarding biological results and cardiac events, and safe with minor side-effects and technical problems. We advise treating homozygous and compound heterozygous children as soon as possible.

Vascular access in lipoprotein apheresis: a retrospective analysis from the UK's largest lipoprotein apheresis centre

INTRODUCTION

Lipoprotein apheresis (LA) has proven to be an effective, safe and life-saving therapy. Vascular access is needed to facilitate this treatment but has recognised complications. Despite consistency in treatment indication and duration there are no guidelines in place. The aim of this study is to characterise vascular access practice at the UK's largest LA centre and forward suggestions for future approaches.

METHODS

A retrospective analysis of vascular access strategies was undertaken in all patients who received LA treatment in the low-density lipoprotein (LDL) Apheresis Unit at Harefield Hospital (Middlesex, UK) from November 2000 to March 2016.

RESULTS

Fifty-three former and current patients underwent 4260 LA treatments. Peripheral vein cannulation represented 79% of initial vascular access strategies with arteriovenous (AV) fistula use accounting for 15%. Last used method of vascular access was peripheral vein cannulation in 57% versus AV fistula in 32%. Total AV fistula failure rate was 37%.

CONCLUSIONS

Peripheral vein cannulation remains the most common method to facilitate LA. Practice trends indicate a move towards AV fistula creation; the favoured approach receiving support from the expert body in this area. AV fistula failure rate is high and of great concern, therefore we suggest the implementation of upper limb ultrasound vascular mapping in all patients who meet treatment eligibility criteria. We encourage close ties between apheresis units and specialist surgical centres to facilitate patient counselling and monitoring. Further prospective data regarding fistula failure is needed in this expanding treatment field.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Efficacy and Safety of Lomitapide in Japanese Patients with Homozygous Familial Hypercholesterolemia

Aim: There is an unmet need in Japan for more optimal lipid-lowering therapy (LLT) for patients with homozygous familial hypercholesterolemia (HoFH) who respond inadequately to available drug therapies and/or apheresis, to achieve goals of low-density lipoprotein cholesterol (LDL-C) reduction by 50% or to < 100 mg/dL.

Methods: In this study, Japanese patients with HoFH on stable LLT and diet were treated with lomitapide, initiated at 5 mg/day and escalated to maximum tolerated dose (up to 60 mg/day) over 14 weeks. The primary efficacy endpoint was mean percentage change from baseline to Week 26 in LDL-C. Secondary endpoints included changes in other lipid parameters and safety throughout the 56-week study (including follow-up).

Results: Nine patients entered the efficacy phase of the study and, of these, eight completed 56 weeks. Mean LDL-C was reduced by 42% (p < 0.0001) at 26 weeks, from 199 mg/dL (95% CI: 149–250) at baseline to 118 mg/dL (95% CI: 70–166). A 50% reduction in LDL-C and LDL-C < 100 mg/dL was achieved by five and six of nine patients, respectively, at 26 weeks. After 56 weeks, LDL-C was reduced by 38% (p = 0.0032) from baseline. Significant reductions in non-HDL-C, VLDL-C, triglycerides, and apolipoprotein B were also reported at Week 26. There were no new safety signals and, similar to previous studies, gastrointestinal adverse events were the most common adverse events.

Conclusion: Lomitapide, added to ongoing treatment with other LLTs, was effective in rapidly and significantly reducing the levels of LDL-C and other atherogenic apolipoprotein B-containing lipoproteins in adult Japanese patients with HoFH.

Multiple large xanthomas: A case report

A 23-year-old male patient presented with multiple large masses in his elbows, buttocks, knees, Achilles tendons, feet, shoulders and hands. The large masses in the elbows and buttocks measured ~6×5×5 cm and ~7×5×4 cm, respectively. The patient presented with an elevated level of low-density lipoprotein cholesterol, and had been previously diagnosed with homozygous familial hypercholesterolemia (FH) and multiple xanthomas. Local surgical excisions were performed to remove the massive xanthomas from the elbows and buttocks, and histological analysis of the surgical specimens confirmed the previous diagnosis of homozygous FH (HoFH). The aim of the present study was to report a rare case of HoFH coinciding with multiple, large and widely-distributed xanthomas and to discuss the clinical characteristics, in order to provide a better understanding of xanthomas and FH.

Dementia Improvement after Plasma Exchange for Familial Hypercholesterolemia

Worldwide dementia related memory issues affect a great number of patients and families. In this case, a "senior moment" was noted at age fifty and issues with memory and mind progressed resulting in early retirement from work. The patient described here was given a diagnosis of "Pre-Alzheimer's disease" and presented for further accurate evaluation, diagnosis, and management. The medical management resulted in an improvement in the patients memory and cognitive ability.

Lomitapide: a review of its use in adults with homozygous familial hypercholesterolemia

Lomitapide (Juxtapid(TM)), an orally administered inhibitor of the microsomal triglyceride transfer protein, inhibits the synthesis of chylomicrons and very low-density lipoprotein, thereby reducing plasma levels of low-density lipoprotein cholesterol (LDL-C). Lomitapide is used to lower lipid levels in adults with homozygous familial hypercholesterolemia, a rare, potentially life-threatening genetic disease that is commonly caused by mutations in the LDL receptor gene or other genes that affect the function of the LDL receptor. In a multinational single-arm, open-label, 78-week, phase III trial, lomitapide reduced mean plasma LDL-C levels by 50 % from baseline in 23 evaluable adults with homozygous familial hypercholesterolemia over a 26 week treatment period. Reductions from baseline in LDL-C levels were sustained for up to 78 weeks with continued lomitapide treatment. In this study, the initial dosage of lomitapide was 5 mg once daily for two weeks, with upward titration thereafter to 10, 20, 40, and 60 mg at weeks 2, 6, 10, and 14, respectively, or until an individually assessed maximum dosage was achieved. Prior to the start of treatment with lomitapide, other lipid-lowering therapy (including LDL apheresis) was stabilized over a 6-week period, and then continued throughout the lomitapide treatment phase. Lomitapide was generally well tolerated; the most common adverse events in the phase III trial were gastrointestinal events.

Disease-corrected hepatocyte-like cells from familial hypercholesterolemia-induced pluripotent stem cells

The generation of human induced pluripotent stem cells (hiPSCs) from an individual patient provides a unique tool for disease modeling, drug discovery, and cell replacement therapies. Patient-specific pluripotent stem cells can be expanded in vitro and are thus suitable for genetic manipulations. To date, several genetic liver disorders have been modeled using patient-specific hiPSCs. Here, we present the generation of corrected hepatocyte-like cells (HLCs) from hiPSCs of a familial hypercholesterolemia (FH) patient with a homozygous mutation in the low-density lipoprotein receptor (LDLR) gene. We generated hiPSCs from a patient with FH with the mutated gene encoding a truncated non-functional receptor. In order to deliver normal LDLR to the defective cells, we used a plasmid vector carrying the normal receptor ORF to genetically transform the hiPSCs. The transformed cells were expanded and directed toward HLCs. Undifferentiated defective hiPSCs and HLCs differentiated from the defective hiPSCs did not have the ability to uptake labeled low-density lipoprotein (LDL) particles. The differentiated transformed hiPSCs showed LDL-uptake ability and the correction of disease phenotype as well as expressions of hepatocyte-specific markers. The functionality of differentiated cells was also confirmed by indo-cyanine green (ICG) uptake assay, PAS staining, inducible cyp450 activity, and oil red staining. These data suggest that hiPSC technology can be used for generation of disease-corrected, patient-specific HLCs with potential value for disease modeling and drug discovery as well as cell therapy applications in future.

Severe hypercholesterolemia in patients with graft-vs-host disease affecting the liver after stem cell transplantation

OBJECTIVE

To review the available literature on severe hypercholesterolemia occurring in the context of graft-vs-host disease affecting the liver.

METHODS

A literature search was conducted in PubMed for articles on hypercholesterolemia occurring in the context of graft-vs-host disease after allogeneic hematopoietic stem cell transplantation. The review included the type of lipid abnormalities observed, complications, and available management strategies.

RESULTS

Severe hypercholesterolemia can occur in patients who develop graft-vs-host disease after transplant. We describe 8 patients with severe hypercholesterolemia occurring in the context of graft-vs-host disease affecting the liver after hematopoietic stem cell transplantation (7 from the literature and 1 from our institution). No association was observed with a specific age, sex, type of hematologic malignancy, or use of a specific immunosuppressant. The elevated cholesterol is either due to high concentrations of lipoprotein X or low-density lipoprotein. Unlike low-density lipoprotein, lipoprotein X may not be atherogenic.

CONCLUSIONS

Treatment may not be required when lipoprotein X is the major elevated lipoprotein unless hyperviscosity occurs, but treatment is indicated when there is elevation in low-density lipoprotein. Plasmapheresis may be necessary. Ultimate treatment is control of the graft-vs-host disease affecting the liver that would improve or completely resolve the hyperlipidemia.

Optimal management of familial hypercholesterolemia: treatment and management strategies

Familial hypercholesterolemia is an autosomally dominant disorder caused by various mutations in low-density lipoprotein receptor genes. This will lead to elevated levels of total and low-density lipoprotein cholesterol, which may in turn lead to premature coronary atherosclerosis and cardiac-related death. The symptoms are more severe in the homozygous type of the disease. Different options for the treatment of affected patients are now available. Diet therapy, pharmacologic therapy, lipid apheresis, and liver transplantation are among the various treatments. We clinically review the treatment and management strategies for the disease in order to shed light on the optimal management of familial hypercholesterolemia.

Severe hypercholesterolaemia: therapeutic goals and eligibility criteria for LDL apheresis in Europe

PURPOSE OF REVIEW

Despite the use of currently available lipid-lowering therapies, a significant proportion of patients with severe hypercholesterolaemia do not reach treatment goals and consequently remain at increased risk for cardiovascular disease (CVD). On the basis of clinical experience, these patients tend to have the most severe forms of familial hypercholesterolaemia or markedly elevated LDL cholesterol (LDL-C) levels but are unable to tolerate statin therapy.

RECENT FINDINGS

LDL apheresis is currently the best treatment option (or treatment rescue) to bring these patients closer to therapeutic LDL objectives, and has been shown to reduce the risk of CVD along with LDL-C levels. However, criteria for LDL apheresis eligibility and the percentage of patients receiving treatment vary widely from country to country across Europe. Despite the proven benefits of LDL apheresis, access to this procedure remains limited because of its high cost and low availability, reflecting inherent limitations of this treatment modality.

SUMMARY

There is a need to both better define the patient population eligible for LDL apheresis and to create unified European guidelines governing the use of apheresis. In addition to improving access to apheresis where appropriate, new therapies are needed to further decrease LDL-C and reduce the ongoing CVD risk in patients with severe hypercholesterolaemia.

Gene therapy in a humanized mouse model of familial hypercholesterolemia leads to marked regression of atherosclerosis

Background

Familial hypercholesterolemia (FH) is an autosomal codominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Homozygous FH patients (hoFH) have severe hypercholesterolemia leading to life threatening atherosclerosis in childhood and adolescence. Mice with germ line interruptions in the Ldlr and Apobec1 genes (Ldlr^−/−Apobec1^−/−) simulate metabolic and clinical aspects of hoFH, including atherogenesis on a chow diet.

Methods/Principal Findings

In this study, vectors based on adeno-associated virus 8 (AAV8) were used to deliver the gene for mouse Ldlr (mLDLR) to the livers of Ldlr^−/−Apobec1^−/− mice. A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10⁹ genome copies/mouse. Whereas Ldlr^−/−Apobec1^−/− mice fed a western-type diet and injected with a control AAV8.null vector experienced a further 65% progression in atherosclerosis over 2 months compared with baseline mice, Ldlr^−/−Apobec1^−/− mice treated with AAV8.mLDLR realized an 87% regression of atherosclerotic lesions after 3 months compared to baseline mice. Immunohistochemical analyses revealed a substantial remodeling of atherosclerotic lesions.

Conclusions/Significance

Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach. The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.