Myeloproliferative Disease: Markers of Endothelial and Platelet Status in Patients with Essential Thrombocythemia and Polycythemia Vera

Vascular complications are the main cause of morbidity in polycythemia vera (PV) and essential thrombocythemia (ET). To investigate plasma concentrations of soluble P-selectin (sP-Sel.), soluble E-selectin (sE-Sel.) and soluble thrombomodulin (sTM) in relation to the presence of thromboembolic events 38 patients with Chronic Myeloproliferative Disorders (CMD) (14 PV pts and 24 ET pts), 15 age - matched controls and 15 patients with secondary thrombocytosis were studied. Plasma levels of P-Sel., E-Sel. and TM were significantly increased in the group of patients as compared with control subjects (respectively p < 0.001, p < 0.04 and p < 0.01). sP-Sel. levels showed no significant difference between the patients and those with secondary thrombocytosis. No difference in sP-sel levels were also observed between subgroups of CMD patients with and without vascular complications. However, among patients with ET, those with thrombosis had higher sP-Sel levels than those without thrombosis (1.177 +/- 110.48 ng/ml vs 816.25 +/- 99.27 ng/ml). High levels of sE-Sel and sTM were found in CMD patients (71.93 +/- 39.08 ng/ml and 35.81 +/- 20.79 ng/ml, respectively). Plasma sE-Sel. concentration was significantly higher in CMD patients with thrombosis than that in CMD patients without thrombosis (p < 0.001). There was no difference in sTM concentration between two groups. These findings indicate that sustained endothelium and platelet activation is present in patients with ET and PV and it might contribute to the pathogenesis of thromboembolic events in these patients.     

Physical Activity and Hemodynamic Reactivity in Chronic Kidney Disease

Background and objectives: Patients with chronic kidney disease (CKD) have an elevated cardiovascular risk. This study was designed to understand better the presence and strength of the relationship between physical activity and BP and to explore determinants of hemodynamic reactivity.Design, setting, participants, & measurements: Twenty-four patients with CKD (mean age 69.5 yr; 3.1 antihypertensive drugs; estimated GFR 47 ml/min per 1.73 m², albumin/creatinine ratio 403 mg/g) were studied on three occasions during a 6-wk period with 24-h ambulatory BP monitoring and simultaneous activity monitoring with wrist actigraphy.Results: Nondippers were found have a greater level of sleep activity compared with dippers, although the awake activity level was similar (7.06 versus 6.73) between groups (P = 0.042 for interaction). In 3587 BP activity pairs, hemodynamic reactivity was variable between individuals (systolic BP reactivity 1.06 [SD 10.50]; diastolic BP reactivity 0.89 [SD 7.80] heart rate reactivity 1.18 [SD 11.00]); those who were more sedentary had a greater increment in systolic BP compared with those who were less sedentary. Antihypertensive drugs blunted hemodynamic reactivity. Hemodynamic reactivity was greatest between 12 a.m. and 8 a.m., making this a vulnerable period for cardiovascular events.Conclusions: Greater hemodynamic reactivity in sedentary people with CKD offers a possible and thus far unrecognized mechanism of cardiovascular damage. Besides reducing BP, antihypertensive drugs reduce hemodynamic reactivity, which offers another plausible mechanism of cardiovascular protection with their use.In health, BP falls during sleep and rises in the waking hours. This circadian variation in BP is determined in large part by the level of physical activity, which increases both BP and heart rate (HR) in proportion to the vigor of activity (1–10). The diagnosis and treatment of hypertension, however, are based almost exclusively on seated, resting BP that is obtained in physician offices. Because physical activity increases BP, it follows that if BP were to be measured over 24 h during the course of usual activity, people with higher intensity or duration of physical activity may have a higher BP level. Higher BP in turn is related to poorer outcomes. Herein lies a paradox. We know that increased physical activity and fitness level are associated with lower cardiovascular risk (11) and that 24-h ambulatory BP is a prognostically superior marker of cardiovascular outcomes compared with clinic-obtained BP recordings in patients with hypertension (12). In fact, in otherwise healthy individuals, the extent of increase in BP with physical activity is an independent predictor of incident hypertension (13). In those who are referred for exercise testing, BP reactivity is a marker of cardiovascular outcomes (14,15). Thus, it is logical to postulate that a higher level of physical activity over the long-term would foster a greater level of cardiovascular health. Better cardiovascular health in turn may be associated with less increment in hemodynamic reactivity. According to this paradigm, people with sedentary habits would be exposed to greater increments in BP than their more physically active peers. If this in fact is true, then it would be a worthy explanation of the paradox noted.Another reason that physical activity is a potent determinant of the circadian variation in BP is because active individuals are more likely to raise their BP when active and therefore are more likely to manifest a fall in BP when sleeping. The presence of BP “dipping” is also associated with a better prognosis (16); however, it is equally likely that patients who do not demonstrate dipping are nocturnally active (17). Whether nondipping in patients with chronic kidney disease (CKD) is due to poor daytime physical activity (and therefore lack of rise in daytime BP) or to increased nighttime physical activity is unclear. Patients with CKD generally have a low level of physical activity often as a result of cardiopulmonary disease or concomitant illnesses that may restrict activity. Sedentary people are less likely to achieve a restful sleep, which in turn may be associated with less dipping; however, patients with CKD also experience nocturia, which may increase their nighttime activity. In patients with CKD, dipping is impaired, but the factors that are associated with impaired circadian variation in BP are poorly understood (18–20).The relationship between activity and hemodynamic responses in patients with CKD has not been studied. It is important to study this relationship because it may offer clues to why patients with CKD are nondippers. We performed this study to understand better the presence and strength of the relationship between activity and BP so that we may explore the provenance of nondipping in free-living patients with CKD. Another aim of our study was to explore factors that are associated with hemodynamic reactivity and whether hemodynamic reactivity depends on the time of the day.     

Low Concentration of LDL Enhances Platelet Reactivity In Vitro- a Morphological Study

The isolated low density lipoprotein (LDL) has been shown to cause shape change, granule centralization and incomplete degranulation of human blood platelets at concentrations of 50 to 300 μg protein/ml in vitro. About half the number of platelets were discoid at the LDL concentration of 50 μg/ml. If the platelets were pretreated with LDL at a concentration of 100 μg/ml, aggregation could be induced by thrombin (0.015 U/ml) lightly. These results suggested that the LDL-incubated platelets showed a primary activation. These LDL-pretreated platelets showed enhanced sensitivity to thrombin by aggregating at a very low dosage (0.015 U/ml). The primary activation of platelets induced by LDL seemed independent of extracellular calcium when LDL concentrations were higher than 200 μg/ml.     

Influence of Platelet Reactivity on Clinical Outcome of Patients with Stable Coronary Artery Disease

Single antiplatelet therapy with aspirin is actually recommended for cardiovascular prevention in patients with stable coronary disease, whereas dual antiplatelet therapy (aspirin and clopidogrel) represents the established treatment in patients with acute coronary syndromes or stable angina undergoing percutaneous coronary intervention. However, recurrent ischemic events occur in patients on treatment with clopidogrel; this may be due to low responsiveness to this agent, a phenomenon influenced by environmental, clinical, and genetic factors. Different strategies have been tested to overcome this phenomenon, such as increase in clopidogrel loading and maintenance doses and use of newer P2Y12 inhibitors (prasugrel and ticagrelor), which are by now indicated for patients with acute coronary syndromes; the latter agents have been associated with stronger antiplatelet effect than clopidogrel even in patients with stable coronary disease, but further studies are needed to test their net clinical benefit in this setting (reduction of ischemic events without increase in bleeding).     

Increased Platelet Reactivity and Circulating Monocyte-Platelet Aggregates in Patients With Stable Coronary Artery Disease

Objectives. We sought to examine whether patients with stable coronary artery disease (CAD) have increased platelet reactivity and an enhanced propensity to form monocyte-platelet aggregates.Background. Platelet-dependent thrombosis and leukocyte infiltration into the vessel wall are characteristic cellular events seen in atherosclerosis.Methods. Anticoagulated peripheral venous blood from 19 patients with stable CAD and 19 normal control subjects was incubated with or without various platelet agonists and analyzed by whole blood flow cytometry.Results. Circulating degranulated platelets were increased in patients with CAD compared with control subjects (mean [±SEM] percent P-selectin–positive platelets: 2.1 ± 0.2 vs. 1.5 ± 0.2, p < 0.01) and were more reactive to stimulation with 1 μmol/liter of adenosine diphosphate (ADP) (28.7 ± 3.9 vs. 16.1 ± 2.2, p < 0.01), 1 μmol/liter of ADP/epinephrine (51.4 ± 4.6 vs. 37.5 ± 3.8, p < 0.05) or 5 μmol/liter of thrombin receptor agonist peptide (TRAP) (65.7 ± 6.8 vs. 20.2 ± 5.1, p < 0.01). Patients with stable CAD also had increased circulating monocyte-platelet aggregates compared with control subjects (percent platelet-positive monocytes: 15.3 ± 3.0 vs. 6.3 ± 0.9, p < 0.01). Furthermore, patients with stable CAD formed more monocyte-platelet aggregates than did control subjects when their whole blood was stimulated with 1 μmol/liter of ADP (50.4 ± 4.5 vs. 28.1 ± 5.3, p < 0.01), 1 μmol/liter of ADP/epinephrine (60.7 ± 4.3 vs. 48.0 ± 4.8, p < 0.05) or 5 μmol/liter of TRAP (67.6 ± 5.7 vs. 34.3 ± 7.0, p < 0.01).Conclusions. Patients with stable CAD have circulating activated platelets, circulating monocyte-platelet aggregates, increased platelet reactivity and an increased propensity to form monocyte-platelet aggregates.     

The Impact of Mean Platelet Volume (MPV) and JAK-2 Mutation on Thrombosis in Chronic Myeloproliferative Diseases

Thrombosis and bleeding are the main complications of chronic myeloproliferative diseases. Mean platelet volume (MPV) is an important indicator of the platelet activation. The aim of the present study was to assess the interrelationships between MPV, JAK-2 gene mutation and thromboembolic events in patients with ET and PV. Patients with ET (n = 60) and PV (n = 46) were compared to the secondary erythrocytosis group (n = 19); and a control group of age and sex matched healthy volunteers (n = 52). Besides demographic, clinical and laboratory data; thrombotic and hemorrhagic events were recorded for each patient. Platelet counts, MPV and JAK2 mutations were studied; and their relation with thromboembolic events were investigated using SPSS program for statistical analysis. There was no significant difference between groups regarding age (p = 0.188). Mean platelet count was significantly higher in ET group than other groups (p < 0.0001). Mean platelet count in PV group was significantly higher than control (p < 0.0001) and secondary erythrocytosis groups (p < 0.0001). In the ET group, MPV values were significantly lower than the control group and PV group. In the ET group, those with thromboembolia had lower platelet counts. There was no relation between MPV and thromboembolic event rate in PV, ET and secondary erithrocytosis groups; while no event was recorded in the control group. There was no relation between thromboembolic event rate and JAK 2 mutation. The association of JAK-2 mutation and high MPV especially in ET and PV groups does not contribute to the thromboembolic events.     

A Study of Histamine in Myeloproliferative Disease

1. Whole blood histamine content was measured in 80 patients with myeloproliferative disease. Increased levels were found in 60 per cent of patientswith uncontrolled polycythemia vera, in 7 per cent of patients with polycythemia vera being controlled by myelosuppressive therapy, and in 71 percent of a group with "spent" polycythemia, myeloid metaplasia and myelofibrosis.

2. The excretion of histamine in the urine was measured in 60 patients,30 with elevated blood histamine and 30 with normal blood histamine. Theurine findings paralleled the blood findings in 90 per cent of the cases.

3. Measurements of cell-poor and cell-rich fractions of blood showed thatthe histamine is contained in the white cell fraction. Elevated basophil countswere present in 50 per cent of the patients and occurred with the greatestfrequency in the groups with elevated blood and urine histamine. A roughcorrelation between the basophil count and the histamine content of bloodand white cell fractions was observed in normal subjects and most cases withmyeloproliferative disease. Data obtained in some cases of myeloproliferativedisease suggest that the histamine content of the basophil may be abnormaland that other granulocytes may contribute to the total leukocyte histamine.

4. Myelosuppressive agents produced a reduction in histamine (expressedper 10⁹ myeloid cells) and a decrease in urine histamine as control of themyeloproliferative process was achieved. Treatment with phlebotomy aloneproduced no change in histamine levels.

5. The incidence of pruritus, upper gastrointestinal distress and urticarialmanifestations was increased 7-fold, 4-fold and 12-fold, respectively, in patients with elevated histamine levels as compared with those who had normalhistamine levels.

6. Cyproheptadine, a potent antihistaminic, successfully controlled pruritus,relieved pyrosis and suppressed urticarial eruptions in patients with elevatedhistamine levels. Suppression of the reaction to subcutaneously administeredcodeine (a histamine-releaser) afforded objective evidence that cyproheptadine blocked the effects of histamine release in vivo.

7. The metabolism of histamine and the role of elevated histamine levelsin the clinical manifestations and pathophysiology of myeloproliferative diseaseare discussed.

Submitted on September 23, 1965 Accepted on May 24, 1966     

Platelets in Myeloproliferative Disorders. III: Glycoprotein Profile in Relation to Platelet Function and Platelet Density

Membrane glycoproteins (GP) are implicated in platelet functions. In myeloproliferative diseases (MD), some of these functions are known to be perturbed. 16 patients with various MD were investigated for platelet functions (retention to glass beads, epinephrine- and ristocetin-induced aggregation), platelet density distribution and PAS-staining glycoprotein profile on SDS-polyacrylamide-gel-electrophoresis. An abnormal GP pattern (moderate reduction of GP (Ib + Is) and GP IIb with corresponding increase in GP IIIb) was demonstrated but no relation to platelet dysfunction or density distribution was observed. No differences between the various types of MD were noticed although the group of poly-cythaemia vera was the less perturbed for platelet function, platelet density and also GP profile.     

Granulocyte and Platelet Adhesiveness in Malignant Paraproteinaemia,Leukaemia and Myeloproliferative Diseases

Granulocyte and platelet adhesiveness were measured in 36 patients with haematologic diseases, using a glass bead column assay. Platelet adhesiveness (PA) was reduced in malignant paraproteinaemia (13/20), leukaemia (10/11) and myeloproliferative diseases (3/5). Granulocyte adhesiveness (GA) was reduced in most patients with paraproteinaemia and leukaemia, but results of measurements in whole blood and in suspensions of leucocytes in autologous plasma were poorly correlated due to the influence of abnormal platelet function and/or concentration on the measurement of GA in whole blood. The results of experiments combining leucocytes and plasma from patients and controls indicate that impaired GA in paraproteinaemia is due to a plasma factor, whereas a cellular defect is responsible for the reduced GA in leukaemia.     

Evaluation of Platelet Reactivity in Diabetes Mellitus

ABSTRACT. Seventeen patients with insulin-dependent diabetes mellitus, all below the age of 45 years, were studied. Five of them had retinopathy but no other micro- or macrovascular diabetic complications. None of them had any other concurrent disorder or were on any medication but insulin. The results were compared to those of 17 healthy volunteers of comparable age. There was no difference between the two groups in venous platelet counts, serum production of thromboxane B₂ (TXB₂), ADP-induced platelet aggregation or bleeding times. As compared to the controls, the diabetics had significantly elevated blood glucose and glycosylated hemoglobin values. The mean plasma values of β-thromboglobulin, platelet factor 4 and TXB₂ were significantly lower in the patients than in the controls. Thus, our results do not lend support to the current concept that platelet reactivity is enhanced in diabetes mellitus.     

Differential Impact of Clinical and Genetic Factors on High Platelet Reactivity in Patients with Coronary Artery Disease Treated with Clopidogrel and Prasugrel

Aim: High platelet reactivity (HPR) is associated with increased risks of thrombotic events in patients with coronary artery disease. The recently developed ABCD-GENE score identified five clinical and genetic factors (age, body mass index, chronic kidney disease, diabetes, and the CYP2C19 loss-of-function allele) for HPR, although the significance of various stages of each factor is unclear. Methods: Four prospective studies were pooled, in which platelet reactivity was measured using the VerifyNow assay with clopidogrel and prasugrel; genotyping of CYP2C19 was also performed. Each component of the ABCD-GENE score was divided into three subcategories. VerifyNow P2Y12 reactivity units ＞208 were defined as HPR. Results: A total of 184 patients were included, of which 111 (60%) and 51 (28%) had HPR with clopidogrel and prasugrel. Chronic kidney disease had an impact on HPR on both clopidogrel and prasugrel, whereas the impact of diabetes was more evident in patients treated with prasugrel. Although the number of CYP2C19 loss-of-function alleles was clearly associated with a likelihood of HPR with clopidogrel, P2Y12 reactivity units with prasugrel treatment were also significantly and progressively higher in patients with more CYP2C19 loss-of-function alleles. Conclusions: Clinical and genetic factors had a differential effect on a P2Y12 inhibitor reactivity with clopidogrel and prasugrel in patients with coronary artery disease. The severity of the factors also had a different impact on HPR.     

Association of Plasma Adiponectin Concentrations with Chronic Lymphocytic Leukemia and Myeloproliferative Diseases

Adiponectin, an adipocyte-secreted hormone, is an important negative regulator in the immune system and hematopoiesis. In this study, we investigated the association of adiponectin levels with chronic lymphocytic leukemia (CLL) and myeloproliferative diseases (MPDs). We measured adiponectin levels in 19 patients with CLL and 30 patients with MPD (chronic myelogenous leukemia, 15; polycythemia vera, 9; myelofibrosis, 4; essential thrombocythemia, 2). The data were (chronic myelogenous leukemia, 15; polycythemia vera, 9; myelofibrosis, 4; essential thrombocythemia, 2). The data were compared with results from a control group of healthy volunteers who were matched according to age, sex, and body mass index. The adiponectin levels in patients with CLL were lower than in the controls (4.71 +/- 1.33 microg/mL versus 16.61 +/- 3.91 microg/mL; P <.001). They were also significantly lower in patients with MPD than in the controls (8.95 +/- 1.33 microg/mL versus 16.16 +/- 4.77 microg/mL; P <.001). In addition, we compared the adiponectin levels of MPD patients who were treated with interferon (IFN) to the levels of patients who were not treated with IFN. Adipnectin levels were significantly higher in IFN-treated patients (11.03 +/- 1.39 microg/mL versus 6.87 +/- 1.79 microg/mL; P <.001). These results suggest that lymphopoiesis and myelopoiesis negatively influence adiponectin levels. Adiponectin may be related to inflammatory cytokine release. IFN therapy appears to have a positive influence on adiponectin secretion by suppressing inflammatory cytokines. Future studies are needed to prove causality and to provide insight about this hormone's mechanism of action and its potential role regarding the etiology and progression of CLL and MPD.     

Retinal Vessel Diameter and Chronic Kidney Disease in Rural China: A Cross-Sectional Study

Few studies have examined the relationship between retinal microvascular abnormalities and chronic kidney disease (CKD). This study aims to examine the association between retinal vessel diameters and CKD in the rural China in order to provide the scientific basis for the early detection and diagnosis for CKD.Participants and data were extracted from the Handan Eye Study, a population-based cross-sectional study performed from 2006 to 2007. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were summarized by the average arteriolar and venular caliber of each eye. The estimated glomerular filtration rate (eGFR) and a urinary albumin to creatinine ratio (ACR) were recorded. Multivariate logistic regression models were used to determine any associations between CRAE, CRVE, arteriole-to-venule ratio (AVR), retinopathy, and CKD in the recruited participants.CKD was found in was 17.3% (892/5158) of this population with a 0.9% (48/5545) rate of reduced renal function and 16.7% (922/5538) rate of albuminuria. Retinopathy was present in 9.6% (571/5925) of participants. Compared to the 4th quartile of AVR, the first group was found to have a higher risk of albuminuria (odds ratio [OR] = 1.261, 95% confidence interval [95%CI]: 1.015–1.567, P = 0.037) and CKD (OR = 1.240, 95%CI: 1.000–1.537, P = 0.049) after adjustment for potential confounding variables. Retinopathy was associated with the occurrence of albuminuria (OR = 1.340, 95%CI: 1.067–1.685, P = 0.012) and CKD (OR = 1.341, 95%CI: 1.071–1.681, P = 0.010). In participants with diabetes, the ORs for the 1st and 4th quartiles of CRAE and CRVE were 2.292 (95%CI: 1.076–4.881, P = 0.032) and 2.113 (95%CI: 1.006–4.438, P = 0.048), respectively. Among the participants with hypertension, retinopathy was also observed to be associated with CKD (OR = 1.306, 95%CI: 1.003–1.699, P = 0.047).The parameters of retinal vessel diameter may be a useful index evaluating the occurrence and development of CKD.     

Sperm Morphological Features Associated with Chronic Chagas Disease in the Semen of Experimentally Infected Dogs

The presence of trypanosomatids in the reproductive systems of different mammals (causing genital lesions in the acute stage of the disease) may predispose the animals to low semen quality. However, there are no studies examining the alterations in the sperm morphological features in the chronic stage of Trypanosoma cruzi infection. Knowledge of these aspects is important to understand the other ways of transmission of the Chagas disease. Progressive motility, mass motility, concentration, and sperm morphology of 84 ejaculates of dogs that were chronically infected with T. cruzi were evaluated. Most of the findings were consistent with the reference values and with those obtained from healthy control dogs. The scrotal circumference was not correlated with spermatozoa concentration in the infected animals. In conclusion, the T. cruzi Ninoa (MHOM/MX/1994/Ninoa) strain does not cause significant alterations in the semen quality of dogs experiencing chronic Chagas disease (at concentrations of 5 × 10⁴ to 1 × 10⁶ parasites per animal).     

Echocardiographic Assessment of Structural and Functional Cardiac Remodeling in Patients with Predialysis Chronic Kidney Disease

Background: Cardiac remodeling has been demonstrated in patients on hemodialysis and in predialysis patients with chronic kidney disease (CKD). Using functional echocardiographic parameters to study the association of hemodynamic status and predialysis CKD has not yet been established. Methods: From November 2007 to September 2008, ninety‐six patients (50 men and 46 women) with different stages of CKD were enrolled consecutively to undergo echocardiography. Group 1 consisted of 27 patients with mild CKD (CKD stages 1 and 2) and group 2 consisted of 69 patients with moderate/severe CKD (CKD stages 3–5). Results: Higher values were observed for the products of serum calcium and phosphorus, serum phosphorus, and intact parathyroid hormone; lower values were observed for hematocrit and serum albumin in group 2 patients. Higher mitral E and A velocities, longer isovolumic relaxation time, more prevalence of moderate‐to‐severe left ventricular (LV) diastolic dysfunction and higher mitral E/Em value were noted in group 2 patients. Eccentric left ventricular hypertrophy (LVH) had effects on systolic contraction disturbance in group 2 patients. CKD severity without LVH had effects on LV filling pressure elevation and relaxation impairment. Among biochemical and echocardiographic parameters, mitral E/Em was most independently associated with a diagnosis of moderate/severe CKD (odds ratio = 1.29, P = 0.023) and it was the most predictive variable with sensitivity and specificity values for a cutoff value of ≥13 of 64% and 74%, respectively. Conclusions: CKD severity without LVH increased LV filling pressure and impaired LV relaxation. Mitral E/Em was significantly associated with moderate/severe CKD. (Echocardiography 2010;27:621‐629)