Lipoprotein-associated phospholipase A2: how effective as a risk marker of cardiovascular disease and as a therapeutic target?

Lipoprotein-associated phospholipase A2 (Lp-PLA2) has been studied extensively in terms of biology, pathophysiology, diagnostic and prognostic values. Lp-PLA2 is an enzyme produced in atherosclerotic plaque by inflammatory cells, linked to LDL, HDL and VLDL. The binding of Lp-PLA2 to a specific lipoprotein fraction renders it more atherogenic. Increasing evidence has demonstrated Lp-PLA2 as a novel "ideal" marker for CVD as of its high specificity for vascular inflammation and low biologic variability. Thus, determination of Lp-PLA2 in individuals may provide clinically relevant information about their future risk of CVD events. In addition, Lp-PLA2 has been considered as a therapeutic target, which has been acted upon indirectly (lipid lowering medications) and directly (Lp-PLA2 antagonists such as darapladib) in pharmacologic therapies. This review will provide an overview on biochemistry, biology, proatherogenic, proinflammatory and proapoptotic effects of Lp-PLA2. Clinical utility and its validity as an independent CVD biomarker as well as a diagnostic biomarker to be detected in the very early stages of atherosclerosis will be also discussed. Moreover, the role of Lp-PLA2 as a pharmacologic therapeutic target is another theme of this review.

Evaluation of the interference of hemoglobin, bilirubin, and lipids on Roche Cobas 6000 assays.

BACKGROUND: Pre-analytical error accounts for major total laboratory errors. We assessed the impacts of hemolysis, icterus, and lipemia on laboratory tests on Roche Cobas 6000. METHODS: Various concentrations of hemoglobin, bilirubin, or Intralipid® were added into the plasma to simulate hemolytic, icteric, or lipemic samples. The analytes were then measured on Roche Cobas 6000 and the change of the analyte concentrations was determined. RESULTS: For most of the chemistry assays, our data were in a good agreement with Roche package inserts. However some assays had significant interference at lower index values while others were affected at higher index than the Roche package inserts indicated. In addition, we observed the positive interference by hemolysis on ALT, lipase, total protein, potassium, and iron. Negative interference was noted on calcium and CK. Most of the immunoassays were not affected by hemoglobin, bilirubin, and lipids although there were a few exceptions. Several therapeutic drugs were affected either positively or negatively by hemolysis, icterus, or lipemia to a certain extent. CONCLUSIONS: We have demonstrated some test interferences which have not been reported previously on the Cobas 6000. The implementation of the cut-off indices on Cobas 6000 would provide more accurate test result reporting.

[Study on the mitochondrial DNA variation in patients with type 2 diabetes mellitus].

OBJECTIVE: To explore the relationship between type 2 diabetes mellitus (T2DM) and the mutations in the fragment of mitochondrial DNA (mtDNA) from nucleotides 3153 to 3551, which have shown high frequency of point mutation. METHODS: One hundred and ninety-one normal controls and 222 patients with T2DM were screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), T-A cloning sequencing and denatured high performance liquid chromatography (DHPLC) techniques. RESULTS: The prevalence of mtDNA mutations in the patient group (24.32%) was significantly higher than that in the control group (7.33%) (P < 0.05). Three novel mutations of A3209T, T3253G and A3467C were found, and C3497T was first reported in DM. Onset age, body mass index, fasting blood glucose, HbA1C, high density lipoprotein-cholesterol and diabetic nephropathy could be related to occurrence of mtDNA mutations (P < 0.05). CONCLUSION: Mitochondrial DNA mutations might implicate T2DM in Wenzhou population, which should play an important role in the pathogenesis of T2DM.

[Detecting of mtDNA mutations at position A3243G and G3316A in patients with type 2 diabetes mellitus in Wenzhou].

To investigate the frequencies of mitochondria DNA (mtDNA) tRNA(Leu (UUR)) point mutation A3243G and NADH dehydronase subunit 1(ND1) gene point mutation G3316A in Wenzhou area of Zhejiang Province, and to explore the correlation between these mutations and the clinical manifestations in patients with type 2 mellitus diabetes(T2DM). Two hundreds and forty-four unrelated patients with T2DM and 156 healthy subjects without family history of T2DM were enrolled in Wenzhou area in this study and screened for the point mutations mentioned above with polymerase chain reaction (PCR) and restricted fragment length polymorphism(RFLP) analysis. The heterogeneous mutations were confirmed with DNA sequencing and denaturing high performance liquid chromatography (DHPLC) following T-A cloning of PCR products. The percentage of A3243G mutation in group of patients with T2DM and control were 0.410% and 0.0% (1/244 vs 0/156), respectively; however, there's not any significant difference between these two groups in frequency of A3243G mutation (P>0.05). G3316A mutation was detected in 4 of 244 cases with T2DM (1.639%) and 2 of 156 healthy controls (1.282%), showing that there's also no statistic difference between these two groups in frequency of G3316A mutation (P>0.05). It's shown that the frequency of mtDNA tRNA(Leu (UUR)) A3243G mutation is fairly low in patients with T2DM in Wenzhou area. Thus it's reasonable to assume that this mutation may not be involved in the development and progression of T2DM. Furthermore, it's demonstrated that the rate of G3316A mutation of mtDNA ND1 gene is rare in patients with T2DM in Wenzhou area and this mutation also happened in healthy control. It's suggested that G3316A mutation is just a gene polymorphism of mtDNA and not related to the pathogenesis of T2DM.