Genetic and clinical characteristics of patients with lipoprotein lipase deficiency from Slovenia and Pakistan: case series and systematic literature review.

Introduction: Hypertriglyceridemia (HTG) is a complex disorder caused by genetic and environmental factors that frequently results from loss-of-function variants in the gene encoding lipoprotein lipase (LPL). Heterozygous patients have a range of symptoms, while homozygous LPL deficiency presents with severe symptoms including acute pancreatitis, xanthomas, and lipemia retinalis. Methods: We described the clinical characteristics of three Slovenian patients (an 8-year-old female, an 18-year-old man, and a 57-year-old female) and one Pakistani patient (a 59-year-old male) with LPL deficiency. We performed next-generation sequencing (NGS) targeting all coding exons and intron-exon boundaries of the LPL gene, and Sanger sequencing for variant confirmation. In addition, we performed a systematic literature review of all cases with three identified variants and described their clinical characteristics. Results: Two Slovenian patients with a heterozygous pathogenic variant NM_000237.3:c.984G>T (p.Met328Ile) were diagnosed within the first three years of life and had triglyceride (TG) values of 16 and 20 mmol/L. An asymptomatic Pakistani patient with TG values of 36.8 mmol/L until the age of 44 years, was identified as heterozygous for a pathogenic variant NM_000237.3:c.724G>A (p.Asp242Asn). His TG levels dropped to 12.7 mmol/L on dietary modifications and by using fibrates. A Slovenian patient who first suffered from pancreatitis at the age of 18 years with a TG value of 34 mmol/L was found to be homozygous for NM_000237.3:c.337T>C (p.Trp113Arg). Conclusions: Patients with LPL deficiency had high TG levels at diagnosis. Homozygous patients had worse outcomes. Good diet and medication compliance can reduce severity.

Revascularization of Peripheral Arteries in Patients with Intermittent Claudication Decreases Inflammatory Biomarkers.

Patients with intermittent claudication have significantly higher levels of inflammatory biomarkers, particularly interleukins, which is also a consequence of exercise limitation. Physical activity, which is one of the preventive measures against atherosclerosis, is associated with a decrease in inflammatory biomarkers. Therefore, in our study, we investigated the effects of revascularization of peripheral arteries in patients with intermittent claudication on functional capacity and levels of inflammatory markers. The study included 26 patients with intermittent claudication who underwent percutaneous transluminal angioplasty (PTA). Before the procedure and 2-4 months after successful revascularization, the ankle-brachial index (ABI), functional capacity using the treadmill test, and the walking impairment questionnaire (WIQ) were determined. Inflammatory biomarkers were also measured before and after procedures. Successful revascularization was associated with an increase in intermittent claudication: 120 (20-315) versus 300 (100-1000 m), P < 0.001. Treadmill testing showed a significant increase in initial and maximal walking distance. After revascularization, ABI increased significantly (0.55 vs 0.82, P < 0.003). Improvement in functional performance was also demonstrated by WIQ. Two to three months after revascularization, some inflammatory biomarkers decreased significantly: fibrinogen, interleukin-6 (IL-6), and interleukin-8 (IL-8). The high-sensitivity C-reactive protein (hsCRP) and tumor necrosis factor-alpha (TNFα) also did not decrease significantly. The levels of some inflammatory markers: IL-6, TNFα, and fibrinogen were significantly related to the improvement in patients' functional capacity. The results of our study show that successful revascularization of the lower limb arteries not only improves the functional capacity of patients with intermittent claudication, but also reduces the systemic inflammatory response and may have a preventive effect on local and concomitant other atherosclerotic diseases.

Characteristics of atherosclerosis in femoropopliteal artery and its clinical relevance.

Atherosclerosis is a systemic disease with different faces. Despite identical or similar pathogenetic mechanisms, atherosclerotic lesions and their clinical manifestations vary in different parts of the vascular system. Peripheral arterial disease (PAD) represents one of the most frequent clinical manifestations of atherosclerosis with predominant location in the superficial femoral artery (SFA). Morphological characteristics of atherosclerotic plaques in peripheral arteries differ from lesions in the coronary and carotid arteries. Plaques in SFA have more fibrotic components, less lipids and inflammatory cells, which makes them more stable and less prone to rupture. Factors that determine the different structure of plaques in SFA compared to coronary arteries include hemodynamic forces, vasa vasorum and calcification. Low shear stress in SFA in the adductor canal is one of the factors which determines frequent atherosclerotic lesions in this region. Lower lipid content and fewer inflammatory cells explain higher stability of SFA plaques. The specific structure of SFA plaques may require preventive and therapeutic measures, which to some extent differ from prevention of coronary atherosclerosis and may include inhibition of fibrotic proliferation in SFA plaques and calcification. Revascularization of PAD differs from procedures used in coronary arteries and requires specific technical expertise and devices.

Case Report: Liver Transplantation in Homozygous Familial Hypercholesterolemia (HoFH)-Long-Term Follow-Up of a Patient and Literature Review.

Homozygous familial hypercholesterolemia (HoFH) is a rare inherited metabolic disorder, frequently leading to an early cardiovascular death if not adequately treated. Since standard medications usually fail to reduce LDL-cholesterol (LDL-C) levels satisfactorily, LDL-apheresis is a mainstay of managing HoFH patients but, at the same time, very burdensome and suboptimally effective. Liver transplantation (LT) has been previously shown to be a promising alternative. We report on a 14 year-long follow-up after LT in a HoFH patient. At the age of 4, the patient was referred to our institution because of the gradually increasing number of xanthomas on the knees, elbows, buttocks, and later the homozygous mutation c.1754T>C (p.Ile585Thr) on the LDL-receptor gene was confirmed. Despite subsequent intensive treatment with the combination of diet, statins, bile acid sequestrant, probucol, and LDL-apheresis, the patient developed valvular aortic stenosis and aortic regurgitation by 12 years. At 16 years, the patient successfully underwent deceased-donor orthotopic LT. Nine years post-LT, we found total regression of the cutaneous xanthomas and atherosclerotic plaques and with normal endothelial function. Fourteen years post-LT, his clinical condition remained stable, but LDL-C levels have progressively risen. In addition, a systematic review of the literature and guidelines on the LT for HoFH patients was performed. Six of the 17 identified guidelines did not take LT as a treatment option in consideration at all. But still the majority of guidelines suggest LT as an exceptional therapeutic option or as the last resort option when all the other treatment options are inadequate or not tolerated. Most of the observed patients had some kind of cardiovascular disease before the LT. In 76% of LT, the cardiovascular burden did not progress after LT. According to our experience and in several other reported cases, the LDL-C levels are slowly increasing over time post LT. Most of the follow-up data were short termed; only a few case reports have followed patients for 10 or more years after LT. LT is a feasible therapeutic option for HoFH patients, reversing atherosclerotic changes uncontrollable by conservative therapy, thus importantly improving the HoFH patient's prognosis and quality of life.

Genetic and Clinical Characteristics of Patients With Homozygous and Compound Heterozygous Familial Hypercholesterolemia From Three Different Populations: Case Series.

Homozygous familial hypercholesterolemia (HoFH) and compound heterozygous familial hypercholesterolemia (cHeFH) are rare disorders generated by disease-causing variants in both alleles of the LDLR or other familial hypercholesterolemia (FH)-related genes. HoFH and cHeFH are characterized by severely elevated low-density lipoprotein-cholesterol (LDL-C), frequently leading to early cardiovascular disease. We investigated the genetic and clinical characteristics of HoFH and cHeFH patients from the Slovenian FH registry and/or those who were previously diagnosed or managed at our institution (Slovenian, Pakhtun and Albanian ethnicity), where genetic testing is not available. Our study includes seven patients. Their median age at the time of clinical diagnosis was 6.3 years (2.9-12.9 years); 2/7 were females. Two patients were diagnosed through the universal FH screening and five patients were diagnosed due to the presence of xanthomas. All the mutations are present in LDLR gene: 7 different genotypes for HoFH (p.Cys167Leu, p.Asp178Asn, p.Cys243Tyr, p.Gly549Asp, p.Cys27Trp, p.Ile585Thr and p.Val797Met) and p.Gly549Asp/p.Gln384Pro genotype for cHeFH patient. The median initial level of LDL-C was 17.0 mmol/L [655 mg/dL] (range 7.6-21.6 mmol/L). The HoFH/cHeFH patients are clinically and genetically very diverse. The clinical criteria (as Simon Broome criteria) might be applicable already in children to raise suspicion of FH but in some cases fail to distinguish heterozygous FH and HoFH/cHeFH patients. However, genetic testing is helpful in confirming the diagnosis, also for a prompt awareness, better compliance to treatment and family screening.

Extended-release niacin/laropiprant improves endothelial function in patients after myocardial infarction.

Raising high-density lipoprotein cholesterol (HDL-C) is an important strategy for reducing residual cardiovascular risk. In the present study, we sought to assess the effect of extended-release niacin/laropiprant on endothelial function in patients after a myocardial infarction with target low-density lipoprotein cholesterol (LDL-C). In this double-blind, placebo-controlled trial, 63 men (35-60 years of age) after a myocardial infarction were randomized to either niacin/laropiprant (1000/20 mg daily for 4 weeks and 2000/40 mg daily thereafter) or placebo. Flow-mediated dilation (FMD) and nitroglycerin-induced (GTN) dilation of the brachial artery, total cholesterol (TC), LDL-C, HDL-C, triglycerides (TG), lipoprotein(a) [Lp(a)], and apolipoprotein (Apo) A1/B were measured at baseline and after 12 weeks of intervention. FMD significantly increased (from 3.9 ± 5.1 to 9.8 ± 4.4%, p < 0.001) in the niacin/laropiprant group, but not in the placebo group (4.6 ± 4.4 to 6.1 ± 4.4%, p = 0.16) (p = 0.02 for comparison of interventions). GTN dilation also increased in the niacin/laropiprant group (from 12.5 ± 6.1 to 16.7 ± 4.8%, p = 0.02), but not in the placebo group (13.4 ± 5.0 to 15.1 ± 5.2%, p = 0.18), (p = 0.60 for comparison of interventions). Niacin/laropiprant reduced TC and LDL-C (p = 0.05 for both) and increased HDL-C (p < 0.001) without influencing TG, with no changes in the placebo group. Lp(a) (p = 0.026) and ApoB (p = 0.014) were significantly lower in the niacin/laropiprant group, with no difference in the placebo group. ApoA1 did not change in either of the groups (p = 0.13; p = 0.26). FMD and GTN dilation improvements did not correlate with changes in the lipid profile. Niacin/laropiprant improves endothelium-dependent and endothelium-independent dilation of the brachial artery. This improvement does not correlate with changes in lipid parameters.