Oxidized low-density lipoprotein levels circulating in plasma and deposited in the tissues: comparison between Helicobacter pylori-associated gastritis and acute myocardial infarction

The causal effect of Helicobacter pylori infection on coronary heart disease is mediated by the body mass index: a Mendelian randomization study

The association between Helicobacter pylori (H. pylori) infection and coronary heart disease (CHD) remains controversial, with an unclear causal link. This study employed bidirectional Mendelian randomization (MR) method, using H. pylori infection as the exposure, to investigate its causal relationship with CHD diagnosis, prognosis, and potential pathogenesis. H. pylori infection exhibited a causal association with body mass index (BMI) (β = 0.022; 95% CI 0.008-0.036; p = 0.001). Conversely, there was no discernible connection between H. pylori infection and the diagnosis of CHD (OR = 0.991; 95% CI 0.904-1.078; p = 0.842; IEU database; OR = 1.049; 95% CI 0.980-1.118; p = 0.178; FinnGen database) or CHD prognosis (OR = 0.999; 95% CI 0.997-1.001; p = 0.391; IEU database; OR = 1.022; 95% CI 0.922-1.123; p = 0.663; FinnGen database). Reverse MR analysis showed no causal effect of CHD on H. pylori infection. Our findings further support that H. pylori infection exerts a causal effect on CHD incidence, mediated by BMI. Consequently, eradicating or preventing H. pylori infection may provide an indirect clinical benefit for patients with CHD.

Lectin-Like OLR1 3'UTR Rs1050286 Gene Polymorphism and Plasma Oxidized-LDL in Coronary Artery Disease and Their Relation to Cardiovascular Risk and Outcomes

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) has an important role in the genesis of coronary atherosclerosis. Lectin-like ox-LDL receptor 1 (OLR1) contributes to the uptake and internalization of ox-LDL. Genetic polymorphisms have been associated with coronary artery disease (CAD). Here we explore the association of plasma levels of ox-LDL and 3' UTR OLR1 (rs1050286) SNP with CAD risk and in-hospital adverse outcomes.

METHODS

A case-control study enrolled 192 patients with ST-segment elevation myocardial infarction (STEMI), 100 patients with unstable angina, and 100 healthy controls. Baseline, clinical characteristics, and risk scores of the patients were determined. Plasma ox-LDL and other biochemical variables were measured. All subjects are genotyped for OLR1 (rs1050286) by RT-PCR with TaqMan SNP genotyping assay.

RESULTS

Plasma ox-LDL was higher with enhanced sensitivity and specificity in identifying patients with STEMI and was found as a significant independent risk factor for CAD in those two groups. Levels of ox-LDL were increased with increasing poor prognostic factors in STEMI patients that are associated with an increased incidence of some adverse events and in-hospital mortality. Elevated STEMI risk was associated with T allele of OLR1 (rs1050286) (odds ratio of 4.9, 95% CI: 2.6-9.4, p< 0.001). STEMI patients who have T allele exhibited higher risk scores, coronary multivessel narrowing, and elevated incidence of in-hospital major adverse clinical events.

CONCLUSION

These results suggest that plasma ox-LDL, as well as T allele of ORL-1 (rs1050286), is associated with the increased risk for developing STEMI and the associated adverse clinical outcomes.

LncRNA MALAT1 Suppression Protects Endothelium against oxLDL-Induced Inflammation via Inhibiting Expression of MiR-181b Target Gene TOX

Rare studies have been conducted to investigate the exact interactions between lung adenocarcinoma transcript 1 (MALAT1), thymocyte selection-associated high mobility group box (TOX), and miRNAs in the pathogenesis of atherosclerosis (AS). We aim to investigate the crosstalk between MALAT1 and TOX and evaluate whether the regulatory mechanism was associated with the miRNA network. AS tissues were collected to determine the level of MALAT1 expression in AS patients, together with determination of miR-181b expression. Cultured endothelial cells were utilized to analyze the expressions of MALAT1, miR-181b, and TOX in the presence of oxLDL. Luciferase activity assay was conducted to evaluate the potential target sites of miR-181b on MALAT1 and TOX. In this study, we demonstrated that MALAT1 was upregulated in patients with AS. MALAT1 silencing significantly downregulated the expression of the miR-181b target gene TOX via reversing the effect of miR181b. Importantly, positive modulation of miR181b and inhibition of MALAT1 and TOX significantly attenuated oxLDL-induced endothelial inflammation and oxidative stress. Moreover, the MAPK signal pathways in endothelial cells were also inhibited through regulation of above endogenous RNAs. In summary, MALAT1 suppression protects the endothelium from oxLDL-induced inflammation and oxidative stress in endothelial cells by upregulation of miR-181b and downregulation of TOX.

Circulating Oxidized Low-Density Lipoprotein Levels Independently Predict 10-Year Progression of Subclinical Carotid Atherosclerosis: A Community-Based Cohort Study

Aims: To investigate the association between circulating oxidized low-density lipoprotein (ox-LDL) levels and progression of subclinical atherosclerosis and to examine whether this link is independent of other low-density lipoprotein (LDL)-related parameters.

Methods: Totally, 804 subjects who were free of cardiovascular disease at baseline completed risk factor surveys and carotid ultrasound measurements in 2002 and 2012. Modified Poisson regression was performed to examine the association between baseline serum ox-LDL levels and the 10-year risk of progression of carotid atherosclerosis which was defined as the development of at least one new plaque in a previously plaque-free carotid segment at re-examination.

Results: The mean age of the subjects was 58.6 ± 7.7 years at baseline and 43.3% were men. A total of 504 (62.7%) subjects had carotid plaque progression at re-examination. Subjects in the intermediate and highest tertiles of ox-LDL had a significantly higher adjusted risk of atherosclerosis progression than those in the lowest tertile [relative risk (95% confidence interval) 1.17 (1.01–1.34) for the intermediate tertile and 1.23 (1.07–1.42) for the highest tertile]. This association was independent of baseline levels of LDL-C, total LDL particle number, and small LDL particle number.

Conclusion: This study demonstrates that serum ox-LDL levels predict 10-year progression of subclinical atherosclerosis. Moreover, this effect is independent of the cholesterol content, the number, and the size of LDL particles.

Association Between Circulating Oxidized LDL and Atherosclerotic Cardiovascular Disease: A Meta-analysis of Observational Studies

BACKGROUND

Although basic research has suggested that oxidized low-density lipoprotein (ox-LDL) is involved in the pathogenesis of atherosclerosis, population observational studies have yielded conflicting results about the association between circulating ox-LDL and atherosclerotic cardiovascular disease (ASCVD). Therefore, we performed a systematic review and meta-analysis of currently available observational studies to verify the association between circulating ox-LDL and ASCVD.

METHODS

We systematically searched PubMed and the Cochrane Library from their inception to March 27, 2017, for nested case-control studies, case-cohort studies, and prospective cohort studies on the relationship between ox-LDL and ASCVD. Studies that did not assess the hazard ratio, relative risk, or odds ratio of ox-LDL or did not adjust for other risk factors, or those without examination of ox-LDL before collection of ASCVD occurrences were excluded. The summarized effect size was combined using fixed effect models. Subgroup analyses were performed on the basis of study quality, study design, definition of ASCVD events, effect size types, types of ox-LDL assay, ox-LDL contrast level, and whether low-density lipoprotein cholesterol was adjusted in a multivariate model.

RESULTS

A total of 12 included studies consisted of 3 nested case-control studies, 1 case-cohort study, 5 hospital-based cohort studies, and 3 community-based cohort studies. The summary effect size of increased circulating ox-LDL was 1.79 (95% confidence interval, 1.56-2.05) for ASCVD. Similar associations were shown in all subgroups.

CONCLUSIONS

Our findings indicate that increased levels of circulating ox-LDL are associated with clinical ASCVD events. Further well designed community-based cohort studies or intervention studies are needed to confirm our findings.

Potential of lipoproteins as biomarkers in acute myocardial infarction

Acute myocardial infarction (AMI), commonly known as heart attack, is a medical emergency that is potentially fatal if not promptly and properly managed. The early diagnosis of AMI is critically important for the timely institution of pharmacotherapy to prevent myocardial damage and preserve cardiac function. Ischemic insults during AMI cause myocardial tissue damage, releasing the cardiac muscle protein troponin T into the blood stream. Therefore, serum troponin T levels are used as a sensitive and specific indicator of myocardial injury for diagnosing AMI. However, there remains a requirement for developing technologies for more accurate biomarkers or signatures for AMI diagnosis or prognosis. Previous studies have implicated impaired lipid metabolism as a causative factor in AMI development. Lipoproteins are important constituents of lipid metabolism; their levels in the blood stream are a convenient biomarker tool for monitoring lipid metabolism. This review summarizes recent findings (data of studies from 2001 to 2016) regarding the biomarker potentials of various lipoproteins, including low-density lipoprotein, oxidized low-density lipoprotein, high-density lipoprotein, lipoprotein-a, and remnant lipoprotein, for the risk stratification of AMI.

Recent Advances in Fluorescent Angioscopy for Molecular Imaging of Human Atherosclerotic Coronary Plaque

PURPOSE OF REVIEW

In vivo imaging of the native substances, including lipoproteins, that comprise human atherosclerotic plaques is currently beyond the scope of any available imaging techniques. Color and near-infrared fluorescent angioscopy (CFA and NIRFA, respectively) systems have been recently developed for molecular imaging of lipoproteins within the human coronary arterial wall ex vivo and/or in vivo. The author reviews recent findings on lipoprotein deposition in human coronary plaques obtained by these imaging techniques.

RECENT FINDINGS

Using specific biomarkers, native pro-atherogenic substances such as oxidized low-density lipoprotein (ox-LDL), LDL, triglycerides (TG), apolipoprotein B-100 (ApoB-100), and lysophosphatidylcholine (LPC), and the anti-atherogenic substance such as high-density lipoprotein (HDL) were visualized by CFA, and LDL and cholesterol by NIRFA, in coronary plaques obtained from autopsy subjects. The relationship between incidence and plaque morphology differed for each substance. The incidence of ox-LDL and LDL on color fluorescence microscopy correlated well with that observed using immunohistochemical techniques. During coronary catheterization in patients, ox-LDL, LDL, and HDL in coronary plaques were visualized by CFA or NIRFA.

CONCLUSIONS

Using CFA or NIRFA, the distribution of the major native pro-atherogenic and anti-atherogenic lipoproteins and their components within human coronary plaques can be evaluated ex vivo and/or in vivo. Fluorescent angioscopy could help our understanding of the molecular mechanisms of coronary atherosclerosis and in the evaluation of the effects of therapy targeting the substances comprising atherosclerotic coronary plaques.

Oxidative DNA damage and oxidized low density lipoprotein in Type II diabetes mellitus among patients with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is reported to be associated with various extragastrointestinal conditions such as insulin resistance, diabetes mellitus and metabolic syndrome. H. pylori infection and type 2 diabetes mellitus (T2DM) are associated with oxidative stress, this cross-relation between H. pylori induced infection in T2DM and oxidative damage is still debated. Thus, the question arises whether an increase in the serum level of 8-OHdG and Ox-LDL will occurs in patients with T2DM infected H. pylori; this will be through determination and compare frequency of H. pylori infection in T2DM and non-diabetic patients.

METHODS

100 patients presented with history of epigastric discomfort for more than 1 month; 50 patients with T2DM and 50 non-diabetics. Anti-H. pylori IgG using ELISA, fasting and postprandial glucose level, glycated hemoglobin (HbA1c) and body mass index (BMI) was calculated. Serum 8-OHdG and Ox-LDL was measured using ELISA for the 100 patients and 50 control subject.

RESULTS

Rates of H. pylori infection of T2DM and non-diabetic were 66 and 58 %, respectively, (p = 0.001). H. pylori IgG antibody was not correlated with HbA1c either in T2DM (p = 0.06) or non-diabetic (p = 0.25). Serum 8-OHdG level in T2DM with positive H. pylori infection showed a significant difference compared to non-diabetics with positive H. pylori infection (p = 0.001) and higher than that in T2DM with negative H. pylori. A correlation between 8-OHdG concentration and HbA1c in T2DM patients infected with H. pylori was observed (r = 0.39, p = 0.02). Serum Ox-LDL level in T2DM with positive H. pylori infection showed a significant difference compared to diabetics with both negative H. pylori infection and in non-diabetics with positive H. pylori infection (p = 0.001).

CONCLUSIONS

Increased levels of oxidative DNA damage (8-OHdG) and Ox-LDL suggest the mechanistic link between H. pylori infection combined with diabetes and increased generation of ROS and could play as an important image for high risk to atherosclerosis.

Association of LOXIN, a new functional splicing isoform of the OLR1 gene, with severity and prognostic localization of critical coronary artery stenoses

AIMS

To evaluate the association between LOXIN, a new functional protective splicing isoform of the oxidized LDL receptor 1 (OLR1) gene, and the severity of coronary artery stenoses.

METHODS

We analyzed 100 consecutive patients with coronary artery disease (CAD) and 100 controls, all evaluated by a new molecular biology test using highly specific allele primers able to identify the single nucleotide variation (IVS4-14 A>G) in the OLR1 gene (Loxin Test - Technogenetics). All the patients and the controls underwent coronary angiography and, for quantitative evaluation, we used both vessel and stenosis score, and SYNTAX score to evaluate the severity of CAD. Moreover, we defined the prognostic localization of CAD as a critical stenosis (>50%) of the left main and/or proximal segment of left anterior descending artery (LAD). Finally, we evaluated a correlation with the presence of diabetes mellitus, dyslipidemia, hypertension, smoking and family history of CAD.

RESULTS

In this selected population, even though the 'AA nonrisk haplotype' is more frequent in the controls, we did not find any statistically significant correlation between the severity of CAD or the prognostic localization of critical stenosis and the difference of IVS4-14 A>G OLR1 genotype (P > 0.05). CAD patients showed significantly higher frequencies of dyslipidemia and smoking (P < 0.05) than controls, but no significant association was found between overall risk factors and the OLR1 polymorphism.

CONCLUSION

In this selected population, we did not find any correlation of LOXIN with the severity or prognostic localization of CAD on left main and/or proximal LAD.

Localization of oxidized low-density lipoprotein and its relation to plaque morphology in human coronary artery

OBJECTIVES

Oxidized low-density lipoprotein (oxLDL) plays a key role in the formation of atherosclerotic plaques. However, its localization in human coronary arterial wall is not well understood. The present study was performed to visualize deposition sites and patterns of native oxLDL and their relation to plaque morphology in human coronary artery.

METHODS

Evans blue dye (EB) elicits a violet fluorescence by excitation at 345-nm and emission at 420-nm, and a reddish-brown fluorescence by excitation at 470-nm and emission at 515-nm characteristic of oxLDL only. Therefore, native oxLDL in excised human coronary artery were investigated by color fluorescent microscopy (CFM) using EB as a biomarker.

RESULTS

(1) By luminal surface scan with CFM, the % incidence of oxLDL in 38 normal segments, 41 white plaques and 32 yellow plaques that were classified by conventional angioscopy, was respectively 26, 44 and 94, indicating significantly (p<0.05) higher incidence in the latter than the former two groups. Distribution pattern was classified as patchy, diffuse and web-like. Web-like pattern was observed only in yellow plaques with necrotic core. (2) By transected surface scan, oxLDL deposited within superficial layer in normal segments and diffusely within both superficial and deep layers in white and yellow plaques. In yellow plaques with necrotic core, oxLDL deposited not only in the marginal zone of the necrotic core but also in the fibrous cap.

CONCLUSION

Taken into consideration of the well-known process of coronary plaque growth, the results suggest that oxLDL begins to deposit in human coronary artery wall before plaque formation and increasingly deposits with plaque growth, exhibiting different deposition sites and patterns depending on morphological changes.

Specific immunization strategies against oxidized low-density lipoprotein: a novel way to reduce nonalcoholic steatohepatitis in mice

Nonalcoholic steatohepatitis (NASH) is characterized by hepatic lipid accumulation combined with inflammation, which can ultimately progress into cirrhosis. Recently, we demonstrated that deletion of scavenger receptors (SRs) CD36 and SR-A in hematopoietic cells reduced hepatic inflammation. In addition to uptake of modified lipoproteins, CD36 and SR-A are also involved in other functions that can activate the inflammatory response. Therefore, the actual trigger for SR activation during NASH is unclear. Here, we hypothesized that hepatic inflammation is triggered by recognition of oxidized LDL (oxLDL) by Kupffer cells (KCs). To inhibit recognition of oxLDL by KCs, low-density lipoprotein receptor (Ldlr(-/-) ) mice were immunized with heat-inactivated pneumococci, which were shown to induce the production of anti-oxLDL immunoglobulin M (IgM) antibodies, due to molecular mimicry with oxLDL. The mice received a high-fat, high-cholesterol diet during the last 3 weeks to induce NASH. Immunization with pneumococci increased anti-oxLDL IgM levels and led to a reduction in hepatic inflammation, as shown by reduced macrophage, neutrophil, and T cell infiltration, and reduced gene expression of tumor necrosis factor (Tnf), interleukin-6 (Il-6), interleukin-1β (Il-1b), monocyte chemoattractant protein 1 (Mcp1), and fibrosis-related genes. In immunized mice, KCs were smaller and showed fewer cholesterol crystals compared with nonimmunized mice.

CONCLUSION

Antibodies to oxLDL play an important role in the pathogenesis of NASH. Therefore, the potential of phosphorylcholine-based vaccination strategies as a novel tool for the prevention and therapy of NASH should be tested in the future.

CagA-positive Helicobacter pylori strains enhanced coronary atherosclerosis by increasing serum OxLDL and HsCRP in patients with coronary heart disease

BACKGROUND

The role of infection in the pathogenesis of atherosclerosis is still a matter of debate.

AIMS

This study aimed to investigate the effect of CagA-positive Helicobacter pylori (H. pylori) strains infection on coronary atherosclerosis in patients with coronary heart disease and to elucidate how cytotoxin-associated gene A (CagA)-positive H. pylori strains infections were involved in coronary heart disease by examining the levels of serum lipid, high-sensitivity C-reactive protein (hsCRP) and oxidized low-density protein (oxLDL).

METHODS

Recruited for this study were 159 patients with coronary heart disease. The severity of coronary heart disease was estimated by calculating the Gensini score. Serum oxLDL and hsCRP were examined in all subjects. Current H. pylori infection was determined in all participants by means of a modified (13C) urea breath test (>200 dpm classified as positive). IgG antibodies against CagA protein were analyzed by enzyme immunoassays. Antibody titers against CagA (≥8 U/ml) were classified as positive. All subjects were divided into three groups, including an uninfected group (n=30), an H. pylori +CagA- group (n=69), and an H. pylori +CagA+ group (n=60).

RESULTS

Significant differences were found among the three groups in levels of total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, serum hsCRP, oxLDL, and severity of coronary atherosclerosis (p<0.05). The levels of total cholesterol, LDL, apolipoprotein B, serum hsCRP, oxLDL were significantly elevated and the severity of coronary atherosclerosis was significantly increased in H. pylori +CagA+ group (p<0.05).

CONCLUSIONS

More serious coronary atherosclerosis was observed in CHD patients with H. pylori +CagA+ infection. H. pylori +CagA+ infection might be involved in coronary atherosclerosis by modifying serum lipids, enhancing LDL oxidation, and activating the inflammatory responses.

Enhanced expression of haemoglobin scavenger receptor in accumulated macrophages of culprit lesions in acute coronary syndromes

AIMS

Effective clearance of extracellular haemoglobin (Hb) is thought to limit systemic oxidative heme toxicity, which is presumed to contribute to the pathogenesis of plaque instability. We immunohistochemically examined the relationship between intraplaque haemorrhage, 4-HNE (4-hydroxy-2-nonenal), an index of lipid peroxidation, and the Hb scavenger receptor (CD163), using coronary atherectomy specimens from 74 patients with stable angina pectoris (SAP, n = 39) or unstable angina pectoris (UAP, n = 35).

METHODS AND RESULTS

Atherectomy samples were stained with antibodies against glycophorin A (a protein specific to erythrocyte membranes), CD31, 4-HNE, and CD163. Quantitative analysis demonstrated that glycophorin A-positive areas, 4-HNE-positive macrophage score, and CD163-positive macrophage score in UAP patients were significantly higher (glycophorin A, P < 0.0001; 4-HNE-positive macrophage score, P < 0.0001; CD163-positive macrophage score, P < 0.0005) than in SAP patients. The percentage of the glycophorin A-positive area showed a significant positive correlation with the number of CD31-positive microvessels and the 4-HNE-positive macrophage score (microvessels, R = 0.59, P < 0.0001; 4-HNE, R = 0.59, P < 0.0001). Moreover, the CD163-positive macrophage score was positively correlated with glycophorin A-positive area and the 4-HNE-positive macrophage score (glycophorin A, R = 0.58, P < 0.0001; 4-HNE, R = 0.53, P < 0.0001).

CONCLUSION

These findings suggest a positive association among intraplaque haemorrhage, enhanced expression of Hb scavenger receptor, and lipid peroxidation in human unstable plaques.

A review of the postulated mechanisms concerning the association of Helicobacter pylori with ischemic heart disease

Since its discovery, Helicobacter pylori has been implicated in the pathogenesis of several diseases, both digestive and extradigestive. Interestingly, the majority of the extradigestive-related literature is focused on two vascular manifestations: stroke and ischemic heart disease. Potential mechanisms for the establishment of a H. pylori-induced ischemic heart disease have been proposed with regard to chronic inflammation, molecular mimicry, oxidative modifications, endothelial dysfunction, direct effect of the microorganism on atherosclerotic plaques as well as changes regarding traditional or novel risk factors for ischemic heart disease or even platelet-H. pylori interactions. A positive link between H. pylori infection and ischemic heart disease has been suggested by a series of studies focusing on epidemiologic evidence, dyslipidemic alterations, upregulation of inflammatory markers or homocysteine levels, induction of hypercoagulability, oxidation of low-density lipoprotein, causation of impaired endothelial function, detection of H. pylori DNA in atherosclerotic plaques, and participation of certain antigens and antibodies in a cross-reactivity model. There are studies, however, which investigated the relationship between H. pylori and ischemic heart disease with regard to the same parameters and failed to confirm the suggested positive association. Further studies in the direction of interaction between H. pylori and the host's genotype as well as a quest for evidence towards novel risk factors for ischemic heart disease such as oxidative stress, vascular remodeling, vascular calcification, or vasomotor activity, may reveal a field of great interest, thus contributing to the determination of new potential mechanisms.

Neopterin is associated with plaque inflammation and destabilisation in human coronary atherosclerotic lesions

BACKGROUND

Previous studies have shown that recent activation of the inflammatory response in coronary atherosclerotic lesions contributes to rapid progressive plaque destabilisation. Neopterin, a by-product of the guanosine triphosphate pathway, is produced by activated macrophages and serves as an activation marker for monocytes/macrophages.

OBJECTIVE

To elucidate the role of neopterin in coronary plaque destabilisation by immunohistochemical study of the presence of neopterin in coronary atherectomy specimens obtained from patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP).

PATIENTS AND METHODS

All patients underwent atherectomy of the primary atherosclerotic lesions responsible for SAP (n = 25) and UAP (n = 25). Frozen samples were studied with antibodies against smooth muscle cells, macrophages, T cells, neutrophils and neopterin.

RESULTS

In 22/25 patients with UAP, abundant neopterin-positive macrophages were found at the sites of coronary culprit lesions. However, in 25 lesions from patients with SAP, only 11 lesions showed neopterin positivity. Quantitatively, the neopterin-positive macrophage score was significantly higher (p<0.001) in patients with UAP than in patients with SAP. Moreover, the neopterin-positive macrophage score showed a significant positive correlation with the number of neutrophils or T cells, respectively (neutrophils, r = 0.55, p<0.001; T cells, r = 0.70, p<0.001).

CONCLUSIONS

Neopterin can be considered as one of the significant factors in the process of plaque inflammation and destabilisation in human coronary atherosclerotic lesions. Its exact role in the process needs to be investigated further.

Measurement of plasma oxidized low-density lipoprotein and its clinical implications

Oxidized low-density lipoprotein (OxLDL) has been shown to exist in human circulating plasma. Several groups including ours have developed methods for immunologically measuring OxLDL, which have been applied to several clinical, both cross-sectional and prospective, studies. These data clearly show that OxLDL levels correlate well with the severity of cardiovascular diseases. In particular, recent observations suggest that plasma OxLDL levels could be a useful marker for predicting future cardiovascular events; however, substantial differences exist among the different methods of OxLDL measurement. To evaluate the clinical data on circulating OxLDL, a proper understanding of the similarity, differences, and limitation of the methods is needed. This paper summarizes the characteristics of the methods used and recent clinical findings.

Close association between activated platelets and neutrophils in the active phase of ulcerative colitis in humans

BACKGROUND

Neutrophils are considered to play a causative role in inflammatory mucosal injury in ulcerative colitis (UC), and an association between platelets and neutrophils may contribute to the progression of the inflammatory processes. To test this hypothesis, we performed immunohistochemical and flow cytometric analyses on tissue and blood samples from patients with UC.

MATERIALS AND METHODS

Colonic mucosal tissues of patients with active (n = 27) or inactive (n = 16) UC and normal controls (n = 11) were subjected to immunohistochemical staining for markers of activated platelets (glycoprotein IIb/IIIa and P-selectin) and neutrophils (neutrophil elastase, myeloperoxidase, and CD66b). The amounts of stained cells were evaluated by computer-aided morphometry. Peripheral blood samples from patients (n = 8) and healthy volunteers (n = 8) were subjected to comparative flow cytometric analysis of activated platelets.

RESULTS

P-selectin-positive activated platelets were frequently aggregated in the inflamed mucosa, especially in ulcerative lesions, and were close to regions of dense neutrophil infiltration. An increase in the number of activated platelets in the colonic lesions was associated with an increase in infiltrating neutrophils and was related to the severity of the disease. The flow cytometric analysis indicated that circulating platelets of patients with UC were highly activated.

CONCLUSIONS

The present study demonstrated that a close association between activated platelets and neutrophils is a prominent pathological change in both the affected colonic mucosa and peripheral blood of patients with active-phase UC. This suggests that platelet-neutrophil association may play an important role in the progression of inflammatory processes in UC.

The 3'-UTR C>T polymorphism of the oxidized LDL-receptor 1 (OLR1) gene does not associate with coronary artery disease in Italian CAD patients or with the severity of coronary disease

BACKGROUND AND AIM

Oxidized low-density lipoproteins (OxLDLs) play a critical role in endothelial dysfunction, which is implicated in the pathogenesis of atherosclerosis. Vascular endothelial cells internalize and degrade oxLDL through the endothelial lectin-like oxidized LDL receptor 1 (OLR1). OLR1 is up-regulated in several pathological conditions, including hypertension, hyperlipidemia, diabetes, atherosclerosis and inflammation, and represents therefore a good candidate for coronary artery disease (CAD). Recently, a 3'-UTR (188 C>T) SNP in the OLR1 gene has been reported to be associated with coronary artery stenosis and myocardial infarction. In the present study we investigated whether the OLR1 gene 188 C>T SNP is a genetic risk marker for CAD in Italian patients with angiographically defined coronary atherosclerosis, and assessed its relation with clinical and metabolic abnormalities, including severity of disease (classified as restenosis, single- or multiple coronary vessels disease, and MI).

METHODS

The 3'-UTR C>T SNP was detected in real-time PCR in 351 subjects with CAD and in 215 control subjects.

RESULTS

The OLR1-T allele frequencies were 48.9% in the CAD subjects and 47.7% in controls, with no significant difference between the two groups. Also, the 3'-UTR C>T SNP did not associate with any of the parameters of severity of disease. Furthermore, none of the other clinical and metabolic parameters were associated with the OLR1 gene SNP.

CONCLUSIONS

Our observations suggest that, in our population, the 3'-UTR C>T polymorphism of the OLR1 gene is unlikely to play a role in the pathogenesis of coronary artery disease.

Persistent High Levels of Plasma Oxidized Low-Density Lipoprotein After Acute Myocardial Infarction Predict Stent Restenosis

OBJECTIVE

Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to evaluate whether the 6-month outcome could be predicted by measuring plasma oxidized LDL (ox-LDL) levels at the time of hospital discharge.

METHODS AND RESULTS

Plasma ox-LDL levels were measured in 102 patients with AMI undergoing primary coronary stenting using a highly sensitive ELISA method. Measurements were taken on admission and at discharge, and the findings related to the clinical outcome. At 6-month follow-up, angiographic stent restenosis occurred in 25 (25%) of the 102 AMI patients. Plasma ox-LDL levels at discharge were significantly (P=0.0074) higher in the restenosis group than those in the no-restenosis group (1.03+/-0.65 versus 0.61+/-0.34 ng/5 microg LDL protein). Multiple regression analysis showed that only plasma ox-LDL levels at discharge were a statistically significant independent predictor for late lumen loss after stenting (beta=0.645; P<0.0001).

CONCLUSIONS

This prospective study demonstrates that persistence of an increased level of plasma ox-LDL at discharge is a strong independent predictor of stent restenosis at 6-month follow-up in AMI patients.

Localization of oxidized phosphatidylcholine in nonalcoholic fatty liver disease: impact on disease progression

Nonalcoholic steatohepatitis/nonalcoholic fatty liver disease is considered to be a hepatic manifestation of various metabolic disorders. However, its precise pathogenic mechanism is obscure. Oxidative stress and consequent lipid peroxidation seem to play a pivotal role in disease progression. In this study, we analyzed the localization of oxidized phosphatidylcholine (oxPC), a lipid peroxide that serves as a ligand for scavenger receptors, in livers of patients with this steatotic disorder. Specimens of non-alcoholic fatty liver disease (15 autopsy livers with simple steatosis and 32 biopsy livers with steatohepatitis) were examined via immunohistochemistry and immunoelectron microscopy using a specific antibody against oxPC. In addition, scavenger receptor expression, hepatocyte apoptosis, iron deposition, and inflammatory cell infiltration in the diseased livers were also assessed. Oxidized phosphatidylcholine was mainly localized to steatotic hepatocytes and some macrophages/Kupffer cells. A few degenerative or apoptotic hepatocytes were also positive for oxPC. Immunoelectron microscopy showed oxPC localized to cytoplasmic/intracytoplasmic membranes including lipid droplets. Steatotic livers showed enhanced expression of scavenger receptors. The number of oxPC cells was correlated with disease severity and the number of myeloperoxidase-positive neutrophils, but not with the degree of iron deposition. In conclusion, distinct localization of oxPC in liver tissues suggest that neutrophil myeloperoxidase-derived oxidative stress may be crucial in the formation of oxPC and the progression of steatotic liver disease.

Helicobacter pylori and extragastric diseases--other Helicobacters

The involvement of Helicobacter pylori in the pathogenesis of extragastric diseases continues to be an interesting topic in the field of Helicobacter-related pathology. Although conflicting findings have been reported for most of the disorders, a role of H. pylori seems to be important especially for the development of cardiovascular and hematologic disorders. Previously isolated human and animal Helicobacter sp. flexispira and "Helicobacter heilmannii" strains have been validated using polyphasic taxonomy. A novel enterohepatic Helicobacter has been isolated from mastomys and mice, adding to the list of helicobacters that colonize the liver. Genetic targets that may aid the classification of novel Helicobacter species have emerged. Animal models of Helicobacter-induced gastric and hepatobiliary diseases have offered insights to the mechanisms associated with premalignant transformation.