Inflammation in Coronary Microvascular Dysfunction.

Chronic low-grade inflammation is involved in coronary atherosclerosis, presenting multiple clinical manifestations ranging from asymptomatic to stable angina, acute coronary syndrome, heart failure and sudden cardiac death. Coronary microvasculature consists of vessels with a diameter less than 500 µm, whose potential structural and functional abnormalities can lead to inappropriate dilatation and an inability to meet the required myocardium oxygen demands. This review focuses on the pathogenesis of coronary microvascular dysfunction and the capability of non-invasive screening methods to detect the phenomenon. Anti-inflammatory agents, such as statins and immunomodulators, including anakinra, tocilizumab, and tumor necrosis factor-alpha inhibitors, have been assessed recently and may constitute additional or alternative treatment approaches to reduce cardiovascular events in atherosclerotic heart disease characterized by coronary microvascular dysfunction.

Plasma signature of apoptotic microvesicles is associated with endothelial dysfunction and plaque rupture in acute coronary syndromes.

OBJECTIVE: Circulating microvesicles (MV) are surrogate biomarkers of atherosclerosis. However, their role in acute coronary syndromes (ACS) has not been fully elucidated yet. We sought to examine the association of circulating apoptotic MVs with ACS pathophysiology. APPROACH AND RESULTS: One hundred and fifty-three patients (n = 153) were included in the study; 49 patients with ST-elevation myocardial infarction (STEMI), 35 with non-STEMI (NSTEMI), 38 with unstable angina, 15 with stable coronary artery disease and 16 control individuals. Flow cytometry analysis was used to quantify circulating apoptotic/non-apoptotic (phospatidyloserine+/phospatidyloserine-) endothelial cell (EMV), red blood cell (RMV) and platelet (PMV) derived MV. Flow-mediated dilatation (FMD) of the brachial artery was assessed by ultrasound to estimate endothelial function. The inflammatory profile was assessed by serum C-reactive protein (hsCRP) levels. Apoptotic only (but not non-apoptotic) MV were increased in patients with ACS (EMV, P = 2.32 × 10-9; RMV, P = .0019; PMV, P = .01). Hierarchical clustering of the total population of ACS patients (n = 122) by circulating levels of phospatidyloserine+ EMV, RMV and PMV identified two discreet clusters of patients without any differences in traditional risk factors, but significant differences in brachial FMD (5.2% (2.5) vs. 4.1% (2.3), P < .05) that remained significant after adjustment for co-variates. The prevalence of STEMI, a surrogate for plaque rupture and vessel thrombotic occlusion, was significantly higher in the patient cluster with impaired endothelial function (60% vs 32%, P = .016, adjusted odds ratio for STEMI, 3.041, 95%CI, 1.160 to 7.968, p = .024). CONCLUSION: Our findings indicate that the circulating levels of apoptotic MV are increased in ACS patients and their plasma profiles associate with endothelial dysfunction and thrombotic complications in ACS patients.

Oxidative Stress Biomarkers in Coronary Artery Disease.

Oxidative stress plays a central role in atherogenesis, implicated in endothelial dysfunction, coronary plaque formation, and destabilization. Therefore, identifying oxidative stress in the vascular wall by reliable biomarkers could aid in early diagnosis and better coronary artery disease (CAD) prognostication. Because of the short half-life of reactive oxygen species, the current approach is to measure stable products generated by the oxidation of macromolecules in plasma or urine. Most popular oxidative stress biomarkers are oxidized low-density lipoprotein, myeloperoxidase and lipid peroxidation biomarkers, such as malondialdehyde and F2-isoprostanes. Oxidative protein modification biomarkers and oxidized phospholipids have also been studied and discussed in the present review. Most of these biomarkers are associated with the presence and extent of CAD, are elevated in patients with acute coronary syndromes, and may predict outcomes independent of traditional CAD risk factors. However, further standardization of measurement methods and assessment in large randomized clinical trials are required to integrate these biomarkers into clinical practice. In addition, evidence that these biomarkers detect oxidative stress in the vascular wall lacks and more specific biomarkers should be developed to identify vascular oxidative stress. Consequently, several oxidative stress biomarkers have been developed, most of which can be associated with the presence and extent of CAD and event prognosis. However, they still have significant limitations that hinder their integration into clinical practice.

The Greek way to the Register: the establishment and operation of the Register for Clinical Chemists-Clinical Biochemists in Greece.

In Greece, there is no officially organized training in clinical chemistry for scientists. The Greek Society of Clinical Chemistry-Clinical Biochemistry (GSCC-CB), following the encouragement of the EC4/RC decided to organize a voluntary Register for specialists in clinical chemistry. The following criteria for registration were defined: 1) University degree in Chemistry, Biochemistry, Biology, Medicine, Pharmacy or other relevant subject. 2) A total of 9 years of university studies and postgraduate specialization in clinical chemistry-clinical biochemistry. 3) A minimum of 4 years of postgraduate specialization in clinical chemistry-clinical biochemistry on the job. 4) The candidate must be practicing clinical chemistry-clinical biochemistry in a laboratory in a medical environment in Greece. The postgraduate specialization in clinical chemistry-clinical biochemistry includes the laboratory training and the theoretical education. The laboratory training is organized by the GSCC-CB according to the Professional Training Dossier. The theoretical education was organized in a series of 18 "Seminars" which was the content of the "Educational program" of the GSCC-CB. Successful completion of the Educational program leads to a Certificate of Competence. The Greek Register has gained equivalence with the EC4 Register and it has 218 members, more than 80 of whom are European clinical chemists.

Antithrombotic Therapy in Carotid Artery Disease.

The management of asymptomatic atherosclerotic carotid artery disease and the role of antithrombotic therapy is of increasing importance for stroke prevention. Non-invasive imaging of carotid plaques can identify high-risk plaque features that are associated with the risk of plaque rupture. Carotid plaque necrosis, hemorrhage, fibrous cap thinning, and the presence of foam cells have all been correlated with the risk of rupture and onset of neurological symptoms in patients with carotid stenosis. Antiplatelets are currently recommended for patients with a history of ischemic stroke and/or significant carotid artery stenosis, with aspirin and clopidogrel being the most widely used and studied agents. The role of dual antiplatelet therapy remains controversial. Moreover, there is scarce evidence on the role of newer anticoagulant agents in stable patients with carotid artery stenosis. In this review article, we discuss the pathophysiology of carotid atherosclerosis, the use of non-invasive imaging for detecting the vulnerable carotid plaque and summarize the existing clinical evidence on the use of antiplatelet and antithrombotic agents in carotid artery disease.

Insulin-induced vascular redox dysregulation in human atherosclerosis is ameliorated by dipeptidyl peptidase 4 inhibition.

Recent clinical trials have revealed that aggressive insulin treatment has a neutral effect on cardiovascular risk in patients with diabetes despite improved glycemic control, which may suggest confounding direct effects of insulin on the human vasculature. We studied 580 patients with coronary atherosclerosis undergoing coronary artery bypass surgery (CABG), finding that high endogenous insulin was associated with reduced nitric oxide (NO) bioavailability ex vivo in vessels obtained during surgery. Ex vivo experiments with human internal mammary arteries and saphenous veins obtained from 94 patients undergoing CABG revealed that both long-acting insulin analogs and human insulin triggered abnormal responses of post-insulin receptor substrate 1 downstream signaling ex vivo, independently of systemic insulin resistance status. These abnormal responses led to reduced NO bioavailability, activation of NADPH oxidases, and uncoupling of endothelial NO synthase. Treatment with an oral dipeptidyl peptidase 4 inhibitor (DPP4i) in vivo or DPP4i administered to vessels ex vivo restored physiological insulin signaling, reversed vascular insulin responses, reduced vascular oxidative stress, and improved endothelial function in humans. The detrimental effects of insulin on vascular redox state and endothelial function as well as the insulin-sensitizing effect of DPP4i were also validated in high-fat diet-fed ApoE-/- mice treated with DPP4i. High plasma DPP4 activity and high insulin were additively related with higher cardiac mortality in patients with coronary atherosclerosis undergoing CABG. These findings may explain the inability of aggressive insulin treatment to improve cardiovascular outcomes, raising the question whether vascular insulin sensitization with DPP4i should precede initiation of insulin treatment and continue as part of a long-term combination therapy.

The influence of resting heart rate on pulse wave velocity measurement is mediated by blood pressure and depends on aortic stiffness levels: insights from the Corinthia study.

OBJECTIVE: Increased resting heart rate as well as increased arterial stiffness are both independent predictors of cardiovascular events and mortality. Results of previous studies have failed to converge concerning the association between heart rate and arterial stiffness, regardless of other potential confounders, such as age, gender and particularly blood pressure (BP). We aimed to investigate: (a) the degree of association (if any) between resting heart rate and carotid-to-femoral pulse wave velocity (PWV), the gold standard index of arterial stiffness, (b) if the relationship between heart rate and PWV is mediated by BP levels and (c) whether their association is affected by the levels of aortic stiffening. APPROACH: Demographic, hemodynamic, laboratory and clinical data of 1566 subjects from the cross-sectional observational 'Corinthia' study were analyzed using univariate and multivariate regression models. Mediation analysis was performed to test whether mean arterial pressure (MAP) is a significant mediator in the heart rate-PWV relationship. The total population was divided in two groups of low and high arterial stiffness according to the median PWV value (8.6 m s-1). MAIN RESULTS: We found that (i) there is a significant association between heart rate and PWV, regardless of other confounding factors. An increase in heart rate by 20 b.p.m. can increase PWV by 0.5 m s-1. However, this association was significant only for subjects with increased aortic stiffness (PWV > 8.6 m s-1) and not for those with PWV ⩽ 8.6 m s-1. Further, (ii) heart rate-PWV association was partially mediated by MAP. SIGNIFICANCE: Increased resting heart rate is related to increased aortic stiffness, only in subjects with stiffer aortas, regardless of BP and other risk factors and subjects' characteristics. The synergistic prognostic effect of increased arterial stiffness and elevated heart rate on target organ damage, cardiovascular events and mortality should be explored in future studies.

Vascular inflammation and metabolic activity in hematopoietic organs and liver in familial combined hyperlipidemia and heterozygous familial hypercholesterolemia.

BACKGROUND: Familial dyslipidemias of either heterozygous (heFH) or combined (FCH) type lead to accelerated atherogenesis and increased cardiovascular risk. OBJECTIVE: The aim of this study was to investigate in statin-naïve adult patients with familial dyslipidemias whether inflammatory activation and liver, spleen and bone marrow metabolic activity differ compared with normolipidemic subjects and between dyslipidemic groups. METHODS: Fourteen patients with FCH, 14 with heFH, and 14 normolipidemic individuals were enrolled. Serum lipids, high-sensitivity C-reactive protein, and fibrinogen levels were measured, followed by 18F-fluorodeoxyglucose positron-emission tomography/computed tomography imaging. Radiotracer uptake in the aortic wall, spleen, bone marrow, and liver was quantified as tissue-to-background ratio (TBR). RESULTS: Patients with heFH had significantly higher low-density lipoprotein levels compared with those with FCH and controls (P < .001). However, aortic TBRs were higher in FCH compared with heFH patients and controls (P = .02 and P < .001, respectively). FCH patients exhibited higher FDG uptake in the spleen compared with controls (P = .05). In addition, FCH exhibited higher bone marrow FDG uptake compared with heFH patients and controls (P = .03 and P = .02, respectively). FCH had higher liver uptake compared with heFH patients and controls (P < .001 for both). Significant correlations were observed between inflammatory biomarkers and imaging indices as well as between aortic TBR and FDG uptake of hematopoietic organs and liver. CONCLUSIONS: Systemic, as well as vascular inflammation and spleen, bone marrow, and hepatic metabolic activity are increased in patients with FCH despite lower levels of low-density lipoprotein.

Submandibular ectopic thyroid tissue diagnosed by ultrasound-guided fine needle biopsy.

Ectopic thyroid gland is rarely seen in the submandibular region, thereby posing difficult diagnostic and management problems. Two Caucasian women presented with painful swelling in the submandibular region, which increased in size considerably during the preceding months. Ultrasound-guided fine needle biopsy (Ug-FNB) revealed ectopic thyroid tissue. In conclusion, ectopic thyroid gland with or without pathology should be included in the differential diagnosis of submandibular swelling and Ug-FNB should be one of the first diagnostic tools utilized for this rare clinical entity.

The organization of an educational program for specialists in clinical chemistry by the Greek Society of Clinical Chemistry-Clinical Biochemistry.

In Greece, there is no officially organized training in clinical chemistry for scientists. The Greek Society of Clinical Chemistry-Clinical Biochemistry decided to organize an intensive educational program of 18 seminars on clinical chemistry content as it is described in the EC4 Syllabus. The duration of each seminar was about 6 hours and consisted of 6 to 9 lectures. At the end of each seminar there was a voluntary written examination, comprised of 24 multiple choice questions. Successful completion of the Educational program was leading to a Certificate of Competence. Two cycles of the 18 seminars were performed: 1st cycle from October 2003 to December 2005 and 2nd cycle from March 2005 to October 2007. One hundred eighty nine colleagues was the mean attendance per seminar for the seminars of the 1st cycle and 38 colleagues for the seminars of the 2nd cycle. The mean participation to the examination for each seminar was almost 80% for the 1st cycle and 68% for the 2nd cycle. More than 80% of the participants performed Good or Very good in the examination in both cycles. It is estimated that more than 40% of the scientists who practice Clinical Chemistry in Greece, participated to this educational activity. This program is now provided as an e-learning application, and it is open for all scientists who want to follow the discipline of clinical chemistry.

Changes of liver and muscle enzymes activity in patients with rigor.

AIM: We investigated whether changes of liver and muscle enzymes activity are associated with rigor of several causes and have any prognostic significance. METHODS: Seventy-five patients with rigor were prospectively evaluated. Serum enzymes were measured at the onset of rigor and during the three following days. RESULTS: Causes of rigor were bacteremia (n=28), cholangiitis (n=12), protozoan infections (n=9), viral infections (n=10) and platelet transfusions (n=16). Increases in enzymes activity were observed with rigors from infectious causes, but not with that following platelet transfusions. Patients with cholangiitis demonstrated the highest ALT elevations, while those with viral infections the highest CPK levels. In bacteremia, CPK values increased significantly only in cases with dehydration and hypokalemia. CONCLUSIONS: Rigor per se does not cause increases in muscle or liver enzymes activities. Rather these changes are associated with the rigor's causative agent (infectious or not), the patient's general condition and the severity and extent of the underlying disease.

Liver involvement in acute vaso-occlusive crisis of sickle cell disease: prevalence and predisposing factors.

OBJECTIVE: To study the prevalence and predisposing factors of liver involvement in sickle cell disease (SCD) of patients with acute vaso-occlusive crisis. MATERIAL AND METHODS: We prospectively evaluated 41 consecutive patients (44% M, median age 39 years, range 16-56 years) with homozygous (HbSS; 12 cases) or sickle cell-beta thalassemia (HbSbeta-thal; 29 cases), admitted to our Medical Department in the period 2002 to 2004. Severity of crisis was graded by in-house-modified APACHE score; presence of asplenia or functional hyposplenism was also considered. Hematological and biochemical parameters including various relevant enzymes/isoenzymes were followed daily. RESULTS: Despite the fact that only 9 patients (22%) presented with acute painful hepatomegaly, liver involvement was evident in 16 (39%); hepatocellular-type injury was found in 1 patient, cholestatic in 8, and mixed in 7. Severity of crisis was not related to liver involvement (score 20.6 versus 18.2), but liver involvement occurred in the presence of normal spleen function (p<0.001) and platelet counts <500,000/mm(3) (p<0.001) were. Patients with liver involvement, compared with those without, had higher total and direct bilirubin levels (4.3 versus 2.9 mg/dL, p=0.050; 1.9 versus 0.8 mg/dL, p=0.010, respectively), lower hematocrit (19% versus 23%, p=0.030) and longer hospitalization (10 versus 6.3 days, p<0.001). CONCLUSIONS: In SCD, there is a 39% prevalence of acute veno-occlusive involvement of the liver, a figure that is much higher than previously reported. The type of injury is mostly mixed hepatocellular-cholestatic or purely cholestatic and its course is usually benign. Liver involvement occurs more often in patients with normal spleen function and is not associated with the overall severity of the acute episode, both observations being unreported previously.