Association of apoE gene polymorphisms with lipid metabolism in renal diseases

BACKGROUND AND OBJECTIVES

Apolipoprotein E (apoE) plays a central role in the metabolism and homeostasis of lipids. ApoE gene encodes three major isoforms: ε2, ε3 a nd ε4 forming six phenotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4. Disorders of the lipid metabolism and the homeostasis are frequently coexist in renal diseases. The association between gene polymorphisms of apoE and lipid metabolism were not consistent. This meta-analysis was performed to assess the association between gene polymorphisms of apoE and lipid metabolism in renal diseases.

METHODS

A pre-defined literatures search and selection of eligible relevant investigations were performed to extract and collect data from electronic databases.

RESULTS

Sixteen articles were enrolled for the analysis of association between apoE gene polymorphisms and lipid metabolism. Subjects with E3E4 had a higher total cholesterol (TC) than those with E3E3, and subjects with E2E3 had a lower TC than those with E3E3. Subjects with ε2, had a lower TC than those with ε3 or ε4, and subjects with ε4 had a higher TC than those with, ε3. Subjects with E2E2, E2E3 or E4E4 had a higher triglyceride (TG) than those with E3E3. Subjects with ε4 had a higher TG than those with ε3. Subjects with ε2, had a higher level of TG than those with non-ε2. Subjects with E3E4 had a slightly lower high-density lipoprotein (HDL) than those with E3E3. E3E4 appeared to be associated with lower levels of HDL. Subjects with E2E2, E2E3 had a notably lower low-density lipoprotein (LDL) than those with E3E3. Subjects with ε2, had a lower LDL than those with ε3 or ε4 ApoE gene polymorphisms were not associated with very low-density lipoprotein, and lipoprotein (a) [Lp(a)]. Subjects with E2E3 or E2E4 had higher apoE levels than those with E3E3, and subjects with E4E4 had lower apoE levels than those with E3E3.

CONCLUSION

ApoE gene polymorphisms are associated with the expression of TC, TG HDL, LDL, Lp(a) or apoE.

[Thromboembolic complications in nephrotic syndrome]

This review devoted to the nephrotic syndrome (NS) subsequent thrombotic outcomes. The pathogenesis of hypercoagulation disorders that cause venous and arterial vascular system thrombosis are studied. Discussed procoagulant and anticoagulant mechanisms imbalance due to the anticoagulants natural urinal loss, affected by disfunction of the glomerular filter selective permeability, leading to high molecular weight liver-derived proteins (at least of the albumin size) leakage, fibrinolysis depression, excessive liver synthesis of plasma clotting cascade factors and platelet activation. Presented new data on the thrombogenesis at NS concerning the role of endothelial microparticles with high prothrombogenic activity that go from damaged glomerulus endothelial capillary cells into the systemic circulation, which can turn the local renal hypercoagulation (concomitant to the kidney immune inflammation process) into the generalized, working towards the thrombosis development. The most frequent adverse variants of arterial and venous thromboses are studied, specified their basic and general risk factors, as well as individual, varying in different patients. Indications and prophylactic anticoagulant therapy regimen and thrombosis treatment duration in patients with NS are discussed. It also stressed that the decision on time and method of anticoagulant therapy for a NS patients is still a challenge for healthcare providers.

Global Trends in Aspirin Resistance-Related Research from 1990 to 2015: A Bibliometric Analysis

Aspirin resistance can be defined as the inability of the usual dose of aspirin medication to produce its antithrombotic effect. Patients with diabetes or cardiovascular disease are at higher risk of stroke, myocardial infarction or cardiovascular death due to aspirin resistance. The aim of this bibliometric study was to identify and analyse the status and trends of aspirin resistance research production at global level through publications indexed in the Scopus database; this will shed new light on future research trends and help researchers predict dynamic direction of research. Literature search using the Scopus database was conducted to assess publications related to aspirin resistance. The selected publications included the terms related to aspirin resistance in the title, abstract or keywords. The searching was accomplished on 20 March 2016 and can be considered to include all publications up to 31 December 2015. Global cumulative publication output on aspirin resistance consists of 986 papers during 1990-2015. Among the 986 documents, 19 (1.9%) were published before 2000, 567 (57.5%) were published from 2000 to 2009 and 400 (40.6%) were published from 2010 to 2015, with peak of publications on this topic in 2008. The leading country in the field of aspirin resistance was the United States, which had the greatest counts of independent articles (165) and international collaboration articles (44). Turkey was in the second rank with 78 articles, followed by Italy (68), the UK (62) and Poland (60). The total number of citations for all documents was 26,342, and the average citations per document were 26.7. The h-index for all aspirin resistance publications was 82. This study presents the results of the first bibliometric study (including quantitative and qualitative analysis) of scientific publications in the field of aspirin renitence at global level. Aspirin resistance-related researches have notably increased in the last years, especially from 2000 to 2015. The United States is the most prolific country, not only in research quantity but also in quality. Furthermore, Turkey and European countries provided more research related to aspirin resistance than other regions such as the developing countries.

Platelet abnormalities in nephrotic syndrome

Nephrotic syndrome (NS) is a common kidney disease associated with a significantly increased risk of thrombotic events. Alterations in plasma levels of pro- and anti-coagulant factors are involved in the pathophysiology of venous thrombosis in NS. However, the fact that the risk of both venous and arterial thrombosis is elevated in NS points to an additional role for blood platelets. Increased platelet counts and platelet hyperactivity have been observed in nephrotic children. Platelet hyperaggregability, increased release of active substances, and elevated surface expression of activation-dependent platelet markers have been documented. The mechanisms underlying those platelet alterations are multifactorial and are probably due to changes in plasma levels of platelet-interfering proteins and lipid changes, as a consequence of nephrosis. The causal relationship between platelet alterations seen in NS and the occurrence of thromboembolic phenomena remains unclear. Moreover, the efficiency of prophylactic treatment using antiplatelet agents for the prevention of thrombotic complications in nephrotic patients is also unknown. Thus, antiplatelet medication is currently not generally recommended for routine prophylactic therapy.

Antiplatelet resistance and the role of associated variables in stable patients treated with stenting

Introduction

Nowadays, clopidogrel and acetylsalicylic acid (ASA) have become routinely applied therapies in percutaneous coronary interventions (PCI) with stenting.

Aim

Numerous variables can interfere with antiplatelet responsiveness, so we aimed to investigate the role of different variables associated with ASA or clopidogrel resistance in stable coronary artery disease.

Material and methods

A total of 207 patients undergoing elective PCI were included in the analysis. All patients received a loading dose of clopidogrel and ASA during PCI procedure and followed by dual antiplatelet therapy. Clopidogrel and ASA resistance were measured by impedance aggregometry method.

Results

Of the patients, 19.8% had clopidogrel resistance, 18.8% had ASA resistance, 9.2% had both clopidogrel and ASA resistance, and 71.5% were responsive to both drugs. In multivariate analysis, platelet count, angiotensin receptor blocker (ARB) use, and ASA resistance were independent variables associated with clopidogrel resistance, and clopidogrel resistance was the only variable associated with ASA resistance. In differentiating whether clopidogrel resistance exists or not, optimum ASA aggregometry response cut-off values were specified, and in differentiating whether ASA resistance exists or not, optimum clopidogrel aggregometry response cut-off values were specified.

Conclusions

In this study, there was a higher incidence of low responsiveness to ASA when there was a low response to clopidogrel, and vice versa. Angiotensin receptor blocker use, platelet count, and ASA resistance were independent variables associated with clopidogrel resistance. Clopidogrel resistance was the only independent variable associated with ASA resistance. Angiotensin receptor blocker use seems to an independent risk factor for clopidogrel resistance in this study, but this result needs to be verified in other studies.

Aspirin resistance in patients with acute coronary events: risk factors and prevalence as determined by whole blood multiple electrode aggregometry

Objectives: To determine the prevalence of aspirin resistance and associated risk factors based on biochemical parameters using whole blood multiple electrode aggregometry.

Methods:The study was conducted at the outpatients cardiology clinic of the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) from August 2011 to February 2012.

Subjects on aspirin therapy were divided into two groups; first-ever coronary event and recurrent coronary event. Aspirin resistance was measured by a Multiplate^® platelet analyser.

Results: A total of 74 patients (63 male, 11 female), with a mean age of 57.93 ± 74.1years were enrolled in the study. The patients were divided into two groups –first-ever coronary event group (n=52) and recurrent coronary event group (n=22). Aspirin resistance was observed in 12 out of 74 (16%) of the study patients, which consisted of 11 patients from the first-ever coronary event group and one patient from the recurrent coronary event group. There were significant correlations between aspirin resistance and age (r = -0.627; p = 0.029), total cholesterol (r = 0.608; p = 0.036) and LDL (r = 0.694; p = 0.012). LDL was the main predictor for area under the curve (AUC) for aspirin resistance. However, there was no association between aspirin resistance and cardiovascular events in both groups in this study.

Conclusions: Aspirin resistance was observed in 16% of the study population. LDL was the major predictor of aspirin resistance. No association was found in the study between aspirin resistance with recurrent coronary events.

Non-HDL cholesterol is an independent risk factor for aspirin resistance in obese patients with type 2 diabetes

OBJECTIVE

We evaluated the prevalence of aspirin resistance and predictive factors for aspirin resistance in Korean type 2 diabetes patients.

APPROACH AND RESULTS

A total of 1045 type 2 diabetes patients from 11 hospitals who were taking aspirin (100 mg/day for ≥2 weeks) and no other antiplatelet agents were studied to evaluate aspirin resistance. Aspirin resistance was measured in aspirin reaction units using VerifyNow(®). Aspirin resistance was defined as ≥550 aspirin reaction units. Aspirin resistance was detected in 102 of the 1045 subjects (prevalence 9.8%). Aspirin resistance was associated with total cholesterol (P = 0.013), LDL-cholesterol (P = 0.028), and non-HDL cholesterol (P = 0.008) concentrations in univariate analysis. In multivariate logistic regression analysis, only non-HDL cholesterol was associated with aspirin resistance in obese (BMI >25 kg/m(2)) type 2 diabetes patients (adjusted odds ratio 3.55, 95% CI: 1.25-10.05, P = 0.017).

CONCLUSIONS

The prevalence of aspirin resistance in Korean type 2 diabetes patients is 9.8%. Non-HDL cholesterol is an independent risk factor for aspirin resistance, especially in obese type 2 diabetes patients.

Prevalence of and risk factors for aspirin resistance in elderly patients with coronary artery disease

Objective

To assess the prevalence of and related risk factors for aspirin resistance in elderly patients with coronary artery disease (CAD).

Methods

Two hundred and forty-six elderly patients (75.9 ± 7.4 years) with CAD who received daily aspirin therapy (≥ 75 mg) over one month were recruited. The effect of aspirin was assessed using light transmission aggregometry (LTA) and thrombelastography platelet mapping assay (TEG). Aspirin resistance was defined as ≥ 20% arachidonic acid (AA)-induced aggregation and ≥ 70% adenosine diphosphate (ADP)-induced aggregation in the LTA assay. An aspirin semi-responder was defined as meeting one (but not both) of the criteria described above. Based on the results of TEG, aspirin resistance was defined as ≥ 50% aggregation induced by AA.

Results

As determined by LTA, 23 (9.3%) of the elderly CAD patients were resistant to aspirin therapy; 91 (37.0%) were semi-responders. As determined by TEG, 61 patients (24.8%) were aspirin resistant. Of the 61 patients who were aspirin resistant by TEG, 19 were aspirin resistant according to LTA results. Twenty-four of 91 semi-responders by LTA were aspirin resistant by TEG. Multivariate logistic regression analysis revealed that elevated fasting serum glucose level (Odds ratio: 1.517; 95% CI: 1.176–1.957; P = 0.001) was a significant risk factor for aspirin resistance as determined by TEG.

Conclusions

A significant number of elderly patients with CAD are resistant to aspirin therapy. Fasting blood glucose level is closely associated with aspirin resistance in elderly CAD patients.

Prophylaxis of Thromboembolic Events in Patients with Nephrotic Syndrome

OBJECTIVE

To review published literature regarding use of strategies to prevent thrombotic events in patients with nephrotic syndrome (NS).

DATA SOURCES

The MEDLINE/PubMed, EMBASE, and Cochrane databases were queried from 1980 to December 2012 for articles in English using the search terms nephrotic syndrome, thrombosis, thromboembolism, anticoagulation, warfarin, heparin, low-molecular-weight heparin, enoxaparin, dalteparin, tinzaparin, statin, atorvastatin, fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin, aspirin, direct thrombin inhibitor, rivaroxaban, argatroban, lepirudin, bivalirudin, dabigatran, factor Xa inhibitor, fondaparinux, rivaroxaban, clopidogrel, ticlopidine, and prasugrel.

STUDY SELECTION AND DATA EXTRACTION

All relevant original studies, meta-analyses, systematic reviews, guidelines, and review articles were assessed for inclusion. References from pertinent articles were examined for additional content not found during the initial search.

DATA SYNTHESIS

NS leads to multiple complications, including hypercoagulability. A small prospective cohort study used enoxaparin for primary prophylaxis and demonstrated successful prevention of thrombotic events with minimal adverse events. Additional information has come in the form of decision analyses, which show potential decreased morbidity and mortality when primary prophylaxis for thrombotic events is used; however, all data have numerous limitations. Other strategies for thrombus prevention, including statins and antiplatelet agents, also have been investigated.

CONCLUSIONS

When patients with NS are admitted to the hospital, develop an acute medical illness, or acquire an additional thrombotic events risk factor such as surgery, active malignancy, or pregnancy, consideration for primary pharmacologic prophylaxis with appropriately dosed low-molecular-weight heparin or other indicated anticoagulant should include the potential for increased thrombotic events risk in this patient population. Consideration may also be given to the use of primary pharmacologic prophylaxis with low-molecular-weight heparin or oral vitamin K antagonist in patients with membranous nephropathy once the albumin level drops below 2.0–2.5 g/dL. Short-term use of pharmacologic prophylaxis during the first 6 months following diagnosis warrants further investigation.