Antiphospholipid antibody-mediated effects in an arterial model of thrombosis are dependent on Toll-like receptor 4.

Patients with antiphospholipid syndrome (APS) produce antiphospholipid antibodies (aPL) and develop vascular thrombosis that may occur in large or small vessels in the arterial or venous beds. On the other hand, many individuals produce aPL and yet never develop thrombotic events. Toll-like receptor 4 (TLR4) appears to be necessary for aPL-mediated prothrombotic effects in venous and microvascular models of thrombosis, but its role in arterial thrombosis has not been studied. Here, we propose that aPL alone are insufficient to cause thrombotic events in an arterial model of APS, and that a concomitant trigger of innate immunity (e.g. TLR4 activation) is required. We show specifically that anti-ß2-glycoprotein I (anti-ß2GPI) antibodies, a subset of aPL, accelerated thrombus formation in C57BL/6 wild-type, but not TLR4-deficient, mice in a ferric chloride-induced carotid artery injury model. These aPL bound to arterial and venous endothelial cells, particularly in the presence of ß2GPI, and to human TLR4 by enzyme-linked immunoassay. Arterial endothelium from aPL-treated mice had enhanced leukocyte adhesion, compared to control IgG-treated mice. In addition, aPL treatment of mice enhanced expression of tissue factor (TF) in leukocytes induced by the TLR4 ligand lipopolysaccharide (LPS). aPL also enhanced LPS-induced TF expression in human leukocytes in vitro. Our findings support a mechanism in which aPL enhance TF expression by leukocytes, as well as augment adhesion of leukocytes to the arterial endothelium. The activation of TLR4 in aPL-positive individuals may be required to trigger thrombotic events.

The dual role of innate immunity in antiphospholipid syndrome and systemic lupus erythematosus.

Antiphospholipid syndrome (APS), as a primary disease or a secondary syndrome in systemic lupus erythematosus (SLE), is characterized by the presence of antiphospholipid antibodies (aPL) and a clinical event. It is likely that both genetic and environmental factors lead to the development of aPL and progression to disease. However, the precise mechanisms are not known. We hypothesize that innate immune activation plays a dual role in APS and SLE, both in the production of aPL (i.e. "initiation" phase) and in the development of a clinical event (i.e. "effector" phase). We have shown that mice immunized with certain phospholipid-binding proteins (e.g. ß2-glycoprotein I (ß2GPI)), plus a concomitant trigger of innate immunity (e.g. a toll-like receptor 4 (TLR4) ligand), produce a strong ß2GPI-reactive T cell response, resulting in high levels of aPL as well as other SLE autoantibodies. We propose that ß2GPI, through its interaction with apoptotic cells, permits B cell epitope spread to multiple SLE autoantibodies. Innate immune activation is also implicated in a murine model of aPL-enhanced thrombus formation. This dual role of innate immune activation provides new insight into the mechanisms involved in the initiation of aPL and other SLE-related autoantibodies, as well as the development of aPL-mediated disease.

Phospholipid-binding proteins differ in their capacity to induce autoantibodies and murine systemic lupus erythematosus.

We have previously shown that immunization of nonautoimmune mice with the phospholipid-binding protein ß2-glycoprotein I (ß2GPI), in combination with lipopolysaccharide (LPS), induces a murine model of systemic lupus erythematosus (SLE), with sequential emergence of autoantibodies and glomerulonephritis. Here, we determine whether the paradigm for induction of murine SLE extends to other phospholipid-binding proteins. Mice were immunized with a phospholipid-binding protein (prothrombin (PT), protein S, or ß2GPI), or a nonphospholipid-binding protein (glu-plasminogen), in the presence of LPS. The breadth and degree of the autoantibody response, and the frequency of glomerulonephritis, varied among the three proteins, with ß2GPI being the most effective in inducing SLE-like disease. The phospholipid-binding proteins also differed in the pattern of serum cytokines they elicited. The most apparent difference between ß2GPI and the other phospholipid-binding proteins was in their ability to bind to LPS: ß2GPI bound to LPS, while PT and protein S did not. Our data suggest that binding to phospholipid(s) is a necessary, but not sufficient, condition for full induction of murine SLE. We propose that other properties, such as physiologic function, avidity for anionic phospholipids, and degree of interaction with other cell surface and/or circulating molecules (particularly LPS) may determine the range and severity of disease.

Caspase-3-mediated secretion of connective tissue growth factor by apoptotic endothelial cells promotes fibrosis.

Apoptosis of endothelial cells (ECs) is an early pathogenic event in various fibrotic diseases. In this study, we evaluated whether paracrine mediators produced by apoptotic ECs play direct roles in fibrogenesis. C3H mice injected subcutaneously with serum-free medium conditioned by apoptotic ECs (SSC) showed increased skin thickness and heightened protein levels of alpha-smooth-muscle actin (alphaSMA), vimentin and collagen I as compared with mice injected with medium conditioned by non-apoptotic ECs. Fibroblasts exposed to SSC in vitro showed cardinal features of myofibroblast differentiation with increased stress fiber formation and expression of alphaSMA. Caspase-3 silencing in ECs prevented the release of mediators favoring myofibroblast differentiation. To identify the fibrogenic factor(s) released by ECs, the protein contents of media conditioned by either apoptotic or non-apoptotic ECs were compared using SDS-PAGE-liquid chromatography (LC)-tandem mass spectrometry (MS/MS) and two-dimensional LC-MS/MS. Connective tissue growth factor (CTGF) was the only fibrogenic protein found increased in SSC. Pan-caspase inhibition with ZVAD-FMK or caspase-3 silencing in ECs confirmed that CTGF was released downstream of caspase-3 activation. The fibrogenic signaling signatures of SSC and CTGF on fibroblasts in vitro were similarly Pyk2-, Src-family kinases- and PI3K dependent, but TGF-beta-independent. CTGF-immunodepleted SSC failed to induce myofibroblast differentiation in vitro and skin fibrosis in vivo. These results identify caspase-3 activation in ECs as a novel inducer of CTGF release and fibrogenesis.

Endothelial apoptosis and chronic transplant vasculopathy: recent results, novel mechanisms.

Chronic transplant vasculopathy (CTV) is a progressive form of vascular obliteration affecting the arteries, arterioles and capillaries of solid organ transplants. It is characterized by intimal accumulation of mononuclear cells, vascular smooth muscle cells (VSMC), myofibroblasts and connective tissue. Mounting evidence, based on animal models and human biopsy results, suggests that acute and persistent rejection triggering apoptosis of endothelial cells (EC) plays a pivotal role in CTV. The precise mechanisms that underlie the induction of fibroproliferative changes in association with endothelial apoptosis have yet to be clearly delineated. Recent observations in the field of apoptosis research provide some important mechanistic clues. First, endothelial apoptosis creates a state of hyperadhesiveness for mononuclear cells, thus facilitating sustained leukocyte infiltration. Second, phosphatidylserine-dependent engulfment of apoptotic cells by infiltrating mononuclear leukocytes promotes transforming growth factor-beta1 production. Third, apoptosis of EC triggers extracellular matrix (ECM) proteolysis thus initiating the production of fibroproliferative/fibrogenic ECM fragments. The relative importance of these mechanisms in the pathophysiology of CTV will need to be addressed in vivo. Yet, these recent developments provide a new mechanistic framework that will help better define the importance of immune-mediated EC apoptosis in the regulation of vascular repair.

Dyslipidemias and the primary prevention of cardiovascular disease: analysis of the FAMUS primary care register.

BACKGROUND: Primary prevention of cardiovascular disease with a pharmacological approach to dyslipidemias is controversial. Little is known about the clinical management by general practitioners in this area. OBJECTIVES: To evaluate the patterns of treatment of patients in primary prevention who were entered in the FAmily Medicine, Université de Sherbrooke (FAMUS) register and to calculate the probability of their receiving a hypolipidemic agent according to the presence of various risk profiles. PATIENTS AND METHODS: Descriptive study based on the FAMUS prospective primary care register. Data from patients in primary prevention (those who had not sustained a cardiovascular event) were extracted and analyzed. MAIN RESULTS: Of the 52,505 patients in the register, 48, 190 were identified as being in primary prevention. Of these, 22,250 (46.2%) had a complete lipid profile on record, and 2300 had received a prescription for a hypolipidemic agent (4.8%). Patients under pharmacological treatment had significantly higher lipid values. The adjusted relative risk of being treated with a hypolipidemic agent was 1.3 for smokers, 1.3 for diabetic patients, 2.0 for those with a positive family history of premature cardiovascular disease, 2.2 for hypertensives and 3.3 for men over 45 years of age or women over 55 years, compared with patients who were not taking lipid-lowering medications. The number of risk factors was even more strongly associated with the probability of being treated. CONCLUSION: Overall, few patients in primary prevention in the register were treated with a pharmacological agent. The presence of associated risk factors in this study was an important predictor for treatment, suggesting that patients in primary prevention are being evaluated globally as a function of all of their risk factors, not just their lipid and lipoprotein levels. Further attention, nonetheless, needs to be directed to the segment of the population with multiple risk factors whose lipoprotein profile is unknown or who are not being treated to guideline target levels.

Antiplatelet and lipid-lowering therapies for the secondary prevention of cardiovascular disease: are we doing enough?

OBJECTIVE: To evaluate whether current recommendations with respect to the treatment of dyslipidemias and the use of antiplatelet agents are being applied in the secondary prevention of cardiovascular disease in primary care settings. DESIGN: Descriptive study based on data from the FAMUS (FAmily Medicine, Université de Sherbrooke) primary care register. SETTING AND PARTICIPANTS: Two-hundred and thirty-three physicians participating in the FAMUS project contributed information from nonpregnant patients over 20 years of age consulting for a periodic health examination between 1992 and 1996. INTERVENTIONS: Data from patients in secondary prevention (those with or having had angina, a previous myocardial infarction, bypass surgery, coronary angioplasty or peripheral vascular disease) were extracted and analyzed. MAIN RESULTS: Of the 52,505 patients in the register, 4315 (8%) were identified as being in secondary prevention. Overall, 53% were noted as receiving an antiplatelet agent while 4% were taking warfarin therapy. Only 64% (2780) had a complete lipid profile on record while 38% were being treated with a hypolipidemic agent. In the treated group, only 30% had a low density lipoprotein cholesterol level below 3.0 mmol/L compared with 22% in the untreated group. CONCLUSIONS: A large number of patients identified as being in secondary prevention were not screened for dyslipidemias, and, of those who were, the majority were undertreated according to current recommendations. Antiplatelet agents were more widely prescribed but potentially underused.

Informatics methodologies for evaluation research in the practice setting.

A continuing challenge in health informatics and health evaluation is to enable access to the practice of health care so that the determinants of successful care and good health outcomes can be measured, evaluated and analysed. Furthermore the results of the analysis should be available to the health care practitioner or to the patient as might be appropriate, so that he or she can use this information for continual improvement of practice and optimisation of outcomes. In this paper we review two experiences, one in primary care, the FAMUS project, and the other in hospital care, the Autocontrol project. Each project demonstrates an informatics approach for evaluation research in the clinical setting and indicates ways in which useful information can be obtained which with appropriate feed-back and education can be used towards the achievement of better health. Emphasis is given to data collection methods compatible with practice and to high quality information feedback, particularly in the team context, to enable the formulation of strategies for practice improvement.

[Treatment patterns of hypertension in 1996. Data from the Quebec Family Practice, University of Sherbrooke registry]. / Habitudes de traitement de l'hypertension en 1996. Données du registre québécois FAMUS.

OBJECTIVE: To describe the treatment of hypertension, alone or in combination with associated conditions, by a group of general practitioners in the FAMUS network and to compare these treatment patterns to the recommendations of the Canadian Hypertension Society Consensus. DESIGN: Descriptive study based on data collected by 233 physicians in the FAMUS provincial register on hypertensive patients treated in 1996. PARTICIPANTS: Developed between 1992 and 1996, the register contains 52,505 patients, 9,094 of whom have high blood pressure. These patients consulted their general practitioners for a complete examination. The data concern the risk factors for cardiovascular disease and include the list of medications prescribed. MAIN OUTCOME MEASURES: Evaluation of the proportions in which various classes of medications were prescribed, and the most common combinations in relation to the presence or absence of associated conditions. RESULTS: Of the 4,049 hypertensive patients seen in 1996, 50.2% were treated with one medication; 32.9% were treated with more than one medication; and 16.9% received no antihypertensive medication. The most frequently prescribed medications were calcium channel blockers (26.1%), followed by diuretics (25.3%), angiotensin-converting enzyme inhibitors (24.3%), and beta-blockers (20.0%). Other agents made up the remaining 4.3% of prescriptions. The proportions were similar for patients without complications who received one medication. CONCLUSIONS: Results of this study suggest that the new molecules are widely used and that treatment patterns differ from the recommendations of the Canadian Hypertension Society Consensus, particularly in the absence of associated conditions.

Early environmental regulation of forebrain glucocorticoid receptor gene expression: implications for adrenocortical responses to stress.

The adrenal glucocorticoids and catecholamines comprise a frontline of defense for mammalian species under conditions which threaten homeostasis (conditions commonly referred to as stress). Glucocorticoids represent the end product of the hypothalamic-pituitary-adrenal (HPA) axis and along with the catecholamines serve to mobilize the production and distribution of energy substrates during stress. The increased secretion of pituitary-adrenal hormones in response to stress is stimulated by the release of corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP) from neurons in the nucleus paraventricularis. In this way, a neural signal associated with the stressor is transduced into a set of endocrine and sympathetic responses. The development of the HPA response to stressful stimuli is altered by early environmental events. Animals exposed to short periods of infantile stimulation or handling show decreased HPA responsivity to stress, whereas maternal separation, physical trauma and endotoxin administration enhance HPA responsivity to stress. In all cases, these effects persist throughout the life of the animal and are accompanied by increased hypothalamic levels of the mRNAs for CRH and often AVP. The inhibitory regulation of the synthesis for these ACTH releasing factors is achieved, in part, through a negative feedback loop whereby circulating glucocorticoids act at various neural sites to decrease CRH and AVP gene expression. Such inhibitory effects are initiated via an interaction between the adrenal steroid and an intracellular receptor (either the mineralocorticoid or glucocorticoid receptor). We have found that these early environmental manipulations regulate glucocorticoid receptor gene expression in the hippocampus and frontal cortex, regions that have been strongly implicated as sites for negative-feedback regulation of CRH and AVP synthesis. When the differences in glucocorticoid receptor density are transiently reversed, so too are those in HPA responses to stress. Taken together, our findings indicate that the early postnatal environment alters the differentiation of hippocampal neurons. This effect involves an altered rate of glucocorticoid receptor gene expression, resulting in changes in the sensitivity of the system to the inhibitory effects of glucocorticoids on the synthesis of CRH and AVP in hypothalamic neurons. Changes in CRH and AVP levels, in turn, determine the responsivity of the axis to subsequent stressors; increased releasing factor production is associated with increased HPA responses to stress. Thus, the early environment can contribute substantially to the development of stable individual differences in HPA responsivity to stressful stimuli. These data provide examples of early environmental programming of neural systems. One major objective of our research is to understand how such programming occurs within the brain.

Extensions to the fuzzy pointed set with applications to image processing.

In all man-machine systems with image processing functions, an important unsolved problem arises in the treatment of uncertain and incomplete image information. Several frameworks have been suggested for handling uncertain image information including; expert systems, fuzzification, likelihood estimation, and neural networks. In this paper we review those methods. We also present a new method for handling uncertainties by unifying the representations of gray-values and uncertainty into one framework in a way that parallels fuzzy logic. This new framework is based on the application of the extended fuzzy pointed set and an associated algebra to handle uncertain information. We further show how this framework can be used in image processing and artificial intelligence.

Excitatory and inhibitory amino acids in the cerebral cortex of nucleus basalis magnocellularis lesioned rats.

It is well known that pathways arising from the nucleus basalis magnocellularis in the basal forebrain which terminate in the cerebral cortex are involved in cognitive function. The cholinergic system is generally thought to play a large part in these processes from lesion, pharmacological and transplantation studies. With increasing evidence suggesting the involvement of amino acid transmitters in learning and memory processes, it is of interest to also evaluate possible changes in the levels of amino acid transmitters in the cortex of nucleus basalis magnocellularis-lesioned rats. In the present study, 9 cortical amino acids were measured in rats with bilateral lesions of the nucleus basalis magnocellularis. We measured significant reductions in aspartate, alanine and gamma-aminobutyric acid; these were 80%, 75%, and 81%, respectively, of control brain values. These results suggest that changes in the amino acid content of the cerebral cortex following lesion of the nucleus basalis magnocellularis-lesioned rat should perhaps also be considered when evaluating behavioral effects in this model.

Hypercholesterolaemia in childhood: repercussions in adulthood.

The development of atherosclerotic vascular disease is influenced by multiple factors present since early age. Abnormal lipid metabolism, a major cause of atherosclerosis, results from genetic predisposition and is influenced by a variety of exogenous conditions. This article reviews the published studies of serum cholesterol tracking. The Sherbrooke cohort study on serum cholesterol tracking from early infancy to adolescence is described. The role of dietary habits, nutrient intake and other lifestyle-associated factors are scrutinized. Finally, a family-oriented detection of coronary risk factors in adolescence is discussed with emphasis on the future implementation of new genetic techniques.

Canadian Hemodialysis Morbidity Study.

The objective of this study was to determine the probabilities of specific morbid events or death among patients with end-stage renal disease (ESRD) treated by hemodialysis. A prospective cohort study was performed between March 1988 and September 1989 in 18 hemodialysis centers in 13 Canadian cities, representing about one third of the hemodialysis population in Canada. The inception cohort consisted of 496 patients entering hemodialysis who had survived 1 month. The few new hemodialysis patients who received erythropoietin (EPO) in the last 3 months of the study were excluded. Survival curves were compared using the Cox proportional hazards regression model. Older age and history of cardiovascular disease were independently associated with a greater probability of death. Age and history of cardiovascular disease were also associated with a greater probability of nonfatal circulatory events (myocardial infarction, angina requiring hospitalization, or stroke), while a serum albumin level less than or equal to 30 g/L (3.0 g dL) was associated with an increased probability of pulmonary edema. The probability of surviving 12 months without receiving a blood transfusion was 47.2% for males and 27.5% for females. The incidence of non-A, non-B hepatitis, as estimated by unexplained elevations in serum aspartate aminotransferase (AST) values, was not different between patients receiving and not receiving blood transfusions. The probability of hospitalization for any cause was greater for patients with grafts for vascular access than for those with fistulae, for those with a history of cardiovascular disease, for those with a serum albumin level less than or equal to 30 g/L, and for those with renal disease due to diabetes or vascular disease. Hospitalization due to circulatory disease was more likely among those with a history of cardiovascular disease and among those with a lower serum albumin level. Hospitalization for infectious disease was more likely among those with a lower serum albumin level and less likely among those with a fistula for vascular access. Among all patients receiving hemodialysis treatment for more than 6 months, there were 14.8 hospital days per year.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of subcutaneous and intravenous recombinant human erythropoietin for anemia in hemodialysis patients with significant comorbid disease.

While recombinant human erythropoietin (rHuEPO) is an effective therapy for anemia in renal failure, most published studies concern benefits in relatively healthy hemodialysis patients. The present study compares intravenous and subcutaneous administration of rHuEPO in an unselected group of 128 hemodialysis patients who were randomized to receive rHuEPO in an initial dose of 150 U/kg/week in three divided doses by subcutaneous or intravenous injection. Following a 4-week placebo run-in period, patients received rHuEPO until their hemoglobin was stable between 105 and 125 g/l for 4 weeks and then followed for a further 24 weeks. Eighty-three patients completed the study, 45 in the subcutaneous and 38 in the intravenous group. There was no difference in mean hemoglobin at any stage between subcutaneous and intravenous patients. Mean rHuEPO dose at the time of stabilization was significantly lower in the subcutaneous group compared to the intravenous (205.9 +/- 135.4 vs. 274.1 +/- 142.4 U/kg/week; p = 0.019), mean time to hemoglobin target was 9.9 +/- 4.5 weeks for the subcutaneous group and 11.9 +/- 4.9 weeks for the intravenous group (p = 0.037). Time to stabilization was 14.9 +/- 4.7 weeks for the subcutaneous compared to 17.3 +/- 3.9 weeks for the intravenous group (p = 0.006). Diabetic patients had higher dose requirements for rHuEPO at all time points and required a longer time to reach stabilization than nondiabetics (18.6 +/- 4.6 vs. 15.6 +/- 4.3 weeks; p = 0.016). Quality of life estimated by a disease-specific Kidney Disease Questionnaire improved significantly during rHuEPO therapy in both groups. There was no significant change in dialysis prescription throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

The Couvade Syndrome: The biological, psychological, and social impact of pregnancy on the expectant father.

The Couvade syndrome describes the various physical symptoms found in expectant fathers. In this descriptive study, we have attempted to determine the extent to which this syndrome occurs among expectant fathers in Quebec, identify certain risk factors, and observe the repercussions of pregnancy on the social and family behaviour of the expectant father, as well as on the use of health care services.

[Not Available]. / Syndrome de couvade et répercussions bio-psychosociales de la grossesse chez le partenaire de la femme enceinte.

The couvade syndrome describes the various physical symptoms found in expectant fathers. In this descriptive study, we have attempted 1) to determine the extent to which this syndrome occurs among expectant fathers in Quebec, 2) to identify certain risk factors, and 3) to observe the repercussions of pregnancy on the social and family behaviour of the expectant father as well as on the use of health care services. Within four days of delivery, a group of thirty-one fathers completed a multiple-choice questionnaire during an individual interview. Sixty-one per cent reported at least one of twenty-eight physical symptoms listed. It would also appear that the men's relationship with their own father before the age of 12 had an impact on the development of the syndrome.

A progressive neurological syndrome associated with an isolated vitamin E deficiency.

Several authors have recently reported a neurological disorder associated with chronic vitamin E deficiency in man. Except in one patient, this deficiency has always been secondary to an underlying disease resulting in lipid malabsorption. We report a second case of such a neurological syndrome in a patient in whom vitamin E deficiency was an isolated finding. The clinical picture in our patient was characterized by a diffuse muscle weakness most prominent distally and in the lower limbs, generalized areflexia, a decrease in proprioception and vibration sense and slight limb and gait ataxia. His condition improved on alpha tocopherol therapy so that it is very likely that vitamin E deficiency is responsible for his neurological deficit. Since in our patient as well as in several other reported cases this condition has been treatable, it is important that this syndrome be recognized in children presenting a suggestive clinical picture even if they do not have lipid malabsorption.