Should neurologists measure fibrinogen concentrations?
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Biomedical subjects
Publications and source records attributed to Francesca Papa.
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Hypertension is the most important modifiable risk factor for ischemic stroke, and antihypertensive treatment is of paramount importance to reduce the incidence of stroke mortality and morbidity. The significance and best management of hypertension during the first hours after stroke onset, however, are still matters of debate. Cerebral ischemia results in a complex inflammatory cascade; inflammatory mechanisms are also important participants in the pathophysiology of hypertension. There has been a convergence of evidence that is important to consider in managing systemic blood pressure after stroke to ensure an optimal outcome. The identification of useful markers will allow progress in our ability to treat blood pressure in the acute phase of a stroke. The determination of levels of C-reactive protein, an acute-phase inflammation marker, may help to guide our approach in the management of blood pressure in acute ischemic stroke. Whether this target will be useful in the development of risk prediction strategies or therapies for the treatment of stroke in humans is far from clear.
The mechanisms underlying the pathogenesis of cerebral small vessel disease (SVD) are incompletely understood, although it represents a large burden upon healthcare and social service. New experimental and clinical data suggest that inflammatory reactions may play a crucial role in both the initiation and progression of SVD. Inflammatory processes could be involved in the pathogenesis of SVD, and particularly in the development of white matter lesions and leukoaraiosis. These new data regarding the possible effects of inflammatory reactions in SVD may be of more than just academic interest. It may be that adding evaluation of inflammatory markers, such as C-reactive protein, to conventional risk factors will allow more appropriate preventive and therapeutic interventions.
To study the persistence of HIV-specific human naive CD4-lymphocytes in vivo in the absence of antigenic stimulation, we identified 2 HIV-seronegative low-risk subjects carrying CD4-cells specific for gp120 that could be expanded in vitro. CD4 T-cell lines specific for gp120 were generated by stimulation cycles with antigen-pulsed antigen-presenting cells. Clonal analysis was performed by spectratyping and by sequencing of the CDR3 regions of the BV and AV-T-cell receptor (TCR) genes. HIV-specific T cells were expanded in vitro in 1989 and 2004. These lines were generated from naive precursors. Analysis of TCR-BV gene family use and sequencing of the TCR-BV22 hypervariable region revealed a BV22 clonotype in the 1989 line. The BV22-CDR3-based polymerase chain reaction primer confirmed that the 1989 and 2004 T-cell lines contained the same clonotype. In addition, the 1989 and 2004 T cells used the same TCR-AV38 gene family and identical CDR3-AV regions, confirming clonal identity. Similar data for a persistent clonotype defined by BV CDR3 sequencing were obtained from the second subject. In conclusion, naive CD4-cells specific for an HIV antigen not encountered in vivo persisted for more than 10 to 15 years. An extended lifespan, homeostatic proliferation, or the ability of the thymus to issue the same CD4 T-cell clone reiteratively might account for the phenomenon.
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BACKGROUND AND PURPOSE: Several studies have shown, in different populations, that modest elevation of plasma C-reactive protein (CRP) in the range seen in apparently healthy individuals is a strong predictor of future vascular events. Elevated plasma CRP concentrations are also associated with an increased risk of cerebrovascular events and an increased risk of fatal and nonfatal cardiovascular events in ischemic stroke patients. These epidemiological and clinical observations suggest that determination of plasma CRP concentrations could be used as an adjunct for risk assessment in primary and secondary prevention of cerebrovascular disease and be of prognostic value. The aim of this review is to summarize the evidence for CRP as an independent predictor of cerebrovascular events in at-risk individuals and ischemic stroke patients and to consider its usefulness in evaluating prognosis after stroke. SUMMARY OF REVIEW: CRP fulfils most of the requirements of a new risk and prognostic predictor, but several issues await further confirmation and clarification before this marker can be included in the routine evaluation of stroke patients and subjects at risk for cerebrovascular disease. Potentially important associations have been established between elevated plasma CRP concentrations and increased efficacy of established therapies, particularly lipid-lowering therapy with statins. CONCLUSIONS: At present, there is not sufficient evidence to recommend measurement of CRP in the routine evaluation of cerebrovascular disease risk in primary prevention, because there is insufficient evidence as to whether early detection, or intervention based on detection, improves health outcomes, although shared risk of cardiovascular disease indicates this may be of value. In secondary prevention of stroke, elevated CRP adds to existing prognostic markers, but it remains to be established whether specific therapeutic options can be derived from this.
Promising findings suggest that systemic inflammation and neuroinflammation are central features in cerebrovascular disease. Inflammatory mechanisms are also important participants in the pathophysiology of hypertension. Markers of inflammation have been shown to be upregulated in different forms of cerebrovascular disease, and to correlate with vascular risk. The inhibitor nuclear factor-kB/nuclear factor-kB system is considered a major intracellular inflammatory pathway, mediating most of the vascular inflammatory responses. Increasing evidence indicates that hypertension, through the vasoactive peptides angiotensin and endothelin-1, promotes and accelerates the atherosclerotic process via inflammatory mechanisms. Proinflammatory properties of angiotensin II have been demonstrated. The identification of useful markers of inflammation, of new therapeutic targets to interfere with these mechanisms, and the evaluation of the efficacy of anti-inflammatory treatments will allow progress in our ability to combat cerebrovascular disease and the complications of hypertension. Whether these targets will be useful in the development of risk prediction strategies or therapies for the treatment of stroke in humans is far from clear.
Metaphore Pharmaceuticals Inc. is developing M-40403, a superoxide dismutase mimetic, for the potential treatment of pain, dermatological disease and inflammation. The company is also investigating the compound for its potential in the treatment for the side effects associated with chemotherapy and radiation therapy.
In different study populations, several studies have shown that modest C-reactive protein elevation, in the range of apparently healthy individuals, is a strong predictor of future vascular events. Willcox and colleagues summarize the epidemiological and clinical observations that have led to the enthusiastic suggestion that determination of serum C-reactive protein levels could also be used as an adjunct for risk assessment in primary and secondary prevention of cerebrovascular disease. Currently, high-sensitivity C-reactive protein assays as a screening test to ascertain individuals at risk of cerebrovascular disease does not provide an accurate determination of the risk of stroke likelihood, and adequate evidence that early detection improves health outcomes and that an early intervention is likely to have a beneficial impact. High-sensitivity C-reactive protein assays as a screening test, only provide inadequate evidence to be considered as an effective cerebrovascular screening test, especially in the elderly.
BACKGROUND AND PURPOSE: High levels of C-reactive protein (CRP) are associated with an increased risk of future cardiovascular events in ischemic stroke. It has been hypothesized that the benefit of angiotensin-converting enzyme (ACE) inhibitors in patients at high vascular risk may also result from their anti-inflammatory action. Data evaluating this hypothesis are limited in ischemic stroke. METHODS: We conducted a prospective observational study in 507 patients with first-ever ischemic stroke to analyze the effect of ACE inhibitor treatment at the time of stroke onset on CRP levels within the first 24 hours and the relationship to outcome. Risk estimates were calculated according to Cox regression analysis controlled for blood pressure (BP) levels, clinical and neuroradiological confounding variables, and log-normalized CRP levels at entry. RESULTS: ACE inhibitor treatment was associated with lower (2.6-fold; P<0.0001) median CRP levels and with a reduced 2-year cardiovascular risk (hazard ratio, 0.39; 95% CI, 0.29 to 0.53; P<0.0001) compared with a different BP-lowering regimen. The relationship between ACE inhibitor status and log-normalized CRP levels remained significant (P<0.0001) after we controlled for important confounding variables and concomitant treatments. The reduced risk was also evident in multivariable analysis when ACE inhibitor treatment was controlled for BP, associated risk factors, neuroradiological findings, and concomitant treatments (hazard ratio, 0.43; 95% CI, 0.30 to 0.62; P<0.0001). This risk reduction was greatly attenuated and not more significant when log-normalized CRP levels were included (hazard ratio, 0.67; 95% CI, 0.43 to 1.04; P=0.0721) in the model. CONCLUSIONS: Concomitant treatment with ACE inhibitor at the time of an acute stroke is associated with lower inflammatory response and better long-term outcomes, apparently apart from the effects on BP.
Among patients with acute stroke, high blood pressure (BP) and higher levels of circulating C-reactive protein (CRP) at the entry are often associated with poor outcome, although the reason is unclear. If the link between BP and stroke outcome is indeed mediated by inflammatory response, one would expect to see positive associations between BP and CRP. In a prospective observational stroke data bank involving 535 first-ever ischemic stroke patients, we studied the association between BP and baseline concentrations of CRP within 24 hours after stroke onset. The association between BP components and the odds of having an elevated CRP level (> or =1.5 mg/dL) was assessed by logistic regression analysis. An increase in systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), or pulse pressure (PP) was significantly associated with an increase in the odds of having an elevated CRP level, independent of other associated study factors. For each 10 mm Hg increase in SBP, DBP, MAP, or PP, the odds of having a high CRP level increased by 72% (P<0.0001), 10% (P<0.0001), 21% (P<0.0001), and 10% (P<0.0001), respectively. When the same model was rerun, adjusting for all considered BP components, only SBP significantly increased the odds of an elevated CRP level by 77% (P<0.0001). Increased SBP was significantly associated with elevated levels of circulating CRP in ischemic stroke patients. These findings support a possible role of acute hypertension after stroke as an inflammatory stimulus contributing to ischemic brain inflammation.
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Millennium Pharmaceuticals Inc (formerly LeukoSite Inc) and PAION GmbH are developing MLN-519, a ubiquitin/proteasome enzyme inhibitor, for the potential treatment of inflammatory diseases and stroke. MLN-519 is currently undergoing phase I clinical trials in acute stroke and myocardial infarction, and is poised to enter phase II trials.
NCX-4016 is a nitric oxide-aspirin conjugate non-steroidal anti-inflammatory drug that is under investigation by NicOx for the potential treatment of cardiovascular disorders and colon cancer. In April 2002, a phase II clinical trial was initiated in symptomatic peripheral arterial disease, and in March 2003, the University of Michigan was awarded a grant by the NIH to conduct a phase II trial in individuals at risk of colon cancer.
The ubiquitin-proteasome pathway (UPP) is a predominantly non-lysosomal protein degradation pathway responsible for degrading many critical regulatory proteins (e.g., nuclear factor-kappa B). This pathway is widely known for its ubiquitous role in immune and inflammatory responses, control of cell growth and apoptosis. These roles are apparent in the nervous system, but neurons and their neighboring cells also employ the UPP for distinct functions, ranging from development to the co-ordination of cellular responses, injury of the nervous system and brain-specific processes such as aging and memory. Promising results from preclinical studies in animal models indicate that the use of specific proteasome inhibitors to manipulate UPP may prove valuable in treating such conditions as ischemic stroke.
BACKGROUND AND PURPOSE: The measurement of markers of inflammation or thrombosis has been proposed as a method to improve the prediction of risk in patients with vascular disease. We evaluated the usefulness of these markers as predictors of cardiovascular events in ischemic stroke patients. METHODS: We analyzed levels of C-reactive protein (CRP), fibrinogen, and D-dimer within the first 24 hours after stroke onset in 473 first-ever ischemic stroke patients and determined the cumulative survival curves free of cardiovascular events in relation to the level of each of these markers according to the Kaplan-Meier method. We adjusted for possible confounding variables using a multivariate Cox proportional-hazards model. RESULTS: Patients in the highest tertiles of D-dimer, fibrinogen, and CRP were associated with an excess risk of new cardiovascular events of 36% (P=0.0134), 63% (P<0.0001), and 72% (P<0.0001), respectively, compared with patients in the lowest tertile. The patients in the highest tertile of CRP had 4 times the risk (hazard ratio, 4.04; P<0.0001) of a new cardiovascular event. Smoking, age, sex, and body mass index did not modify risk, and risk was independent of other confounding variables and of D-dimer and fibrinogen levels. The use of ticlopidine was associated with a significant risk reduction among patients with lower (86%, P=0.0159) and middle (69%, P<0.0001) levels of CRP, whereas a nonsignificant excess risk (27%, P=0.3896) was evident among those with the highest levels. CONCLUSIONS: Elevated levels of CRP, more than of D-dimer and fibrinogen, are related to the risk of new cardiovascular events after ischemic stroke. The efficacy of antiplatelet therapy in secondary prevention appears to be directly related to level of inflammatory and thrombotic markers.