Lipid profiles and outcome in patients treated by intravenous thrombolysis for cerebral ischemia

OBJECTIVE

To determine whether low low-density lipoprotein cholesterol (LDL-C) but not high-density lipoprotein cholesterol (HDL-C) and triglyceride concentrations are associated with worse outcome in a large cohort of ischemic stroke patients treated with IV thrombolysis.

METHODS

Observational multicenter post hoc analysis of prospectively collected data in stroke thrombolysis registries. Because of collinearity between total cholesterol (TC) and LDL-C, we used 2 different models with TC (model 1) and with LDL-C (model 2).

RESULTS

Of the 2,485 consecutive patients, 1,847 (74%) had detailed lipid profiles available. Independent predictors of 3-month mortality were lower serum HDL-C (adjusted odds ratio [(adj)OR] 0.531, 95% confidence interval [CI] 0.321-0.877 in model 1; (adj)OR 0.570, 95% CI 0.348-0.933 in model 2), lower serum triglyceride levels ((adj)OR 0.549, 95% CI 0.341-0.883 in model 1; (adj)OR 0.560, 95% CI 0.353-0.888 in model 2), symptomatic ICH, and increasing NIH Stroke Scale score, age, C-reactive protein, and serum creatinine. TC, LDL-C, HDL-C, and triglycerides were not independently associated with symptomatic ICH. Increased HDL-C was associated with an excellent outcome (modified Rankin Scale score 0-1) in model 1 ((adj)OR 1.390, 95% CI 1.040-1.860).

CONCLUSION

Lower HDL-C and triglycerides were independently associated with mortality. These findings were not due to an association of lipid concentrations with symptomatic ICH and may reflect differences in baseline comorbidities, nutritional state, or a protective effect of triglycerides and HDL-C on mortality following acute ischemic stroke.

Influence of differences in case mix on the better outcome of smokers after intravenous thrombolysis for acute cerebral ischemia

BACKGROUND/AIMS

Thrombolysis for myocardial infarction is more effective in smokers. Our aim was to determine whether smokers treated by intravenous (i.v.) rt-PA for acute cerebral ischemia have better outcomes.

METHOD

Comparison of smokers and non-smokers for baseline characteristics and month-3 outcome in patients treated by i.v. rt-PA for cerebral ischemia in Lille, France, and Belgrade, Serbia. The primary outcome was a modified Rankin scale (mRS) 0-1 or similar to the pre-stroke mRS. Secondary outcomes were an mRS 0-2 and death.

RESULTS

We included 459 patients (255 men; median age 65 years, interquartile range 52-76; 135 smokers). Smokers were younger (median 53 vs. 70 years, p < 0.0001) and had less severe strokes (median NIHSS 10 vs. 14, p < 0.0001). At month 3, they were more likely to have an mRS 0-1 [odds ratio (OR) 1.75; 95% confidence interval (CI) 1.17-2.62], or an mRS 0-2 (OR 2.90; 95% CI 1.86-4.52) and less likely to be dead (OR 0.28; 95% CI 0.13-0.61). Smoking was not independently associated with outcome after adjustment for case mix [adjusted OR ((adj)OR) 0.86; 95% CI 0.52-1.43].

CONCLUSION

Smoking does not independently influence the outcome in patients treated by rt-PA for cerebral ischemia. The better outcome in smokers is the consequence of differences in case mix.

Influence of lipid profiles on the risk of hemorrhagic transformation after ischemic stroke: systematic review

Background

It has been suggested that low cholesterol levels might be associated with an increased risk of hemorrhagic transformation (HT) in patients with acute cerebral ischemia. We systematically reviewed the literature to determine the influence of lipid profiles on the HT risk.

Methods

We searched PubMed from 1966 and EMBASE from 1980 for studies that investigated the association between lipid profiles and HT. We performed a meta-analysis (weighted mean difference method) for the comparison between presence and absence of HT (all or symptomatic) for total, low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) cholesterol, and triglycerides.

Results

Eight studies investigating 1,763 patients were eligible, but none was designed specifically to address this question. All studies recruited acute stroke patients selected on the presumed cause of cerebral ischemia or treatment received. The meta-analysis showed that: (i) patients with all HT had lower LDL cholesterol levels (p = 0.008) but no difference in HDL cholesterol levels (p = 0.066), total cholesterol (p = 0.129) and triglycerides (p = 0.900); (ii) patients with symptomatic HT had lower total cholesterol levels (p = 0.035) but did not differ in LDL (p = 0.056) and HDL cholesterol (p = 0.138) and triglyceride (p = 0.851) levels.

Conclusion

HT is associated with baseline total and LDL cholesterol levels, but the mechanism of this association needs to be explored to identify preventive strategies.

Modifying effect of arterial hypertension on amyotrophic lateral sclerosis

Given the high oxygen consumption of motor neurons, we sought to assess the frequency and prognostic value of arterial hypertension (affecting brain's oxygen supply) in amyotrophic lateral sclerosis (ALS). We consecutively and prospectively included all ALS patients with regular medical follow-up and documented blood pressure measurements and monitored them until death. Vascular factors diagnosed prior to the onset of motor signs in ALS patients were compared with those in a stratified, age- and gender-matched case-control population. The severity of leukoaraiosis on magnetic resonance imaging (MRI) was blindly assessed. Post mortem examinations were performed when authorized. Compared with controls (n = 408), the 102 ALS patients were significantly more likely to display hypertension (41-57%) and current smoking (15-26%). The number of years of hypertension was associated with survival (HR = 1.04 (1.01-1.07)). In a multivariate analysis, leukoaraiosis severity (HR = 1.214 (1.096-1.344)), current smoking (HR = 1.766 (1.085-2.872)) and low vital capacity (HR = 2.422 (1.266-4.633)) remained independent predictors of survival. Post mortem examinations revealed a greater frequency of leukoaraiosis in ALS patients (p = 0.02). In conclusion, the effect of chronic hypertension on survival might be exerted through abnormal neural perfusion. The higher frequency of recent hypertension in ALS patients may be due to a compensatory increase in blood pressure in response to a lower oxygen supply.

Comparison of 7.0-T T₂*-magnetic resonance imaging of cerebral bleeds in post-mortem brain sections of Alzheimer patients with their neuropathological correlates

BACKGROUND

In view of the increasing recognition of cerebral microbleeds (MCBs) with MRI, there is a need to validate their detection in post-mortem brains in patients with cerebrovascular diseases and dementia.

MATERIALS AND METHODS

Out of 20 post-mortem brains of patients with Alzheimer dementia and with different cerebrovascular lesions, 45 large sections of the cerebral hemispheres, brainstem and cerebellum were submitted to a 7.0-T T₂*-weighted MRI, and afterwards compared to the histological detection of haematomas, MCBs and mini-bleeds (MNBs).

RESULTS

The sensitivity, specificity, predictive positive value and predictive negative value of the T₂* imaging to detect MCBs and MNBs were excellent for those in the cortico-subcortical regions. There was a significant overestimation of MNBs in the striatum due to iron deposits unrelated to old haemorrhages. Also in the deep white matter, 42% of MNBs were not detected, while 31% of T₂* hyposignals were not due to MNBs but to vessels filled with post-mortem thrombi.

CONCLUSIONS

When evaluating the 'bleeding load' with 7.0-T T₂*-weighted MRI in post-mortem brain sections of patients with dementia and vascular risk factors, only quantification of small cerebral bleeds in the cortico-subcortical regions is reliable.

Fetal alcohol-induced hyperactivity is reversed by treatment with the PPARα agonist fenofibrate in a rat model

INTRODUCTION

Exposure to alcohol in utero is linked to the development of a wide range of psychobehavioral changes, notably hyperactivity and attention deficit, with complex underlying pathological and functional mechanisms. Although the currently available treatments for hyperactivity have been studied in children exposed to alcohol in utero, the efficacy of these compounds is subject to debate and has prompted efforts to identify new pharmacological targets.

METHOD

In a rat model of early alcohol exposure (i.e., in utero and during lactation), we studied the effect of the lipid-lowering peroxisome proliferator-activated receptor (PPAR) alpha activator fenofibrate on psychobehavioral impairments.

RESULTS

In the young rat, early exposure to alcohol perturbs locomotor behavior and induces prepubertal hyperactivity and postpubertal hypoactivity. The hyperactivity, usually observed at the end of the fifth week of life, was prevented by the administration of fenofibrate, which also had a beneficial effect on the accompanying attention deficit by reinforcing sustained attention.

CONCLUSION

Our results with fenofibrate suggest that the pharmacological modulation of nuclear receptors such as PPAR-alpha may constitute a new therapeutic approach to managing the psychobehavioral disorders associated with early alcohol exposure.

Overweight induced by chronic risperidone exposure is correlated with overexpression of the SREBP-1c and FAS genes in mouse liver

Weight gain and metabolic disturbances, such as dyslipidemia and hyperglycaemia, are common side effects of most antipsychotic drugs, including risperidone. The aim of this study was to investigate the effects of chronic treatment with risperidone on body weight, fat accumulation, liver weight, and hepatic expression of key genes involved in lipid metabolism in female mice. We also addressed the mechanism of risperidone induction of metabolic side effects by exploring its effect on lipid and cholesterol metabolism in primary cultures of rat hepatocytes. Eleven weeks of treatment with long-acting risperidone (12.5 mpk/week) resulted in a significant weight gain associated with an increase of liver and adipose tissue weight. These effects were positively correlated with hepatic mRNA induction of two key genes involved in lipogenesis: sterol regulatory element binding protein-1c (SREBP-1c) and fatty acid synthase (FAS). Furthermore, in line with these in vivo results, risperidone elicited significant inductions of SREBP-1 maturation and FAS mRNA expression in primary cultures of rat hepatocytes associated with an increase of free fatty acid, triacylglycerol, and phospholipid synthesis as assessed by acetate incorporation. The current investigations underscore the usefulness of a mouse model to study the weight gain observed with risperidone treatment in humans. This study shows that risperidone induces similar effects in the liver (in vivo) and in hepatocyte cell cultures (in vitro) on the expression of key genes and/or proteins that control lipid metabolism. This suggests that risperidone could alter lipid metabolism in the liver and induce weight gain in a way that is partly independent of its action on the central nervous system.

Posterior fossa volume increase after surgery for Chiari malformation Type I: a quantitative assessment using magnetic resonance imaging and correlations with the treatment response

OBJECT

The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a given-sized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions.

METHODS

Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome.

RESULTS

All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months. The mean relative increase in PFV accounted for 10% (range 1.5%-19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = -0.52, p = 0.09) and the basiocciput was short (r = -0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%.

CONCLUSIONS

The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.

Brain ischemia changes the long term response to antidepressant drugs in mice

Depression is a frequent but often unrecognized and under treated complication of stroke that has scarcely been investigated in animal models particularly regarding treatment issues. Using the Forced Swim Test (FST) and testing spontaneous motor activity, we studied whether a transient focal cerebral ischemia modifies mice behaviours and antidepressant drug effects. We first evaluated whether FST realized 2 days or 1 week after brain reperfusion may be routinely used in male Swiss mice previously submitted to a 15, 30 or 60-min transient occlusion of the right middle cerebral artery. We then evaluated behavioural changes up to 5 weeks in mice previously submitted to a 15-min ischemia. Behaviours according to the administration of imipramine or fluvoxamine at 1 and 5 weeks after a 15-min ischemia were finally evaluated. Transient ischemia was associated with a decrease in immobility in the FST performed 2 days after reperfusion while no changes were observed in 1 and 5 weeks post-ischemia groups. Changes were related neither to brain ischemia duration nor to infarct volume. At both 1 and 5 weeks after brain ischemia, a dramatic decrease in the antidepressant response to imipramine related to a decrease in climbing behaviour was observed while the effects of fluvoxamine were improved through an increase in both climbing and swimming. Behaviours in the FST were unrelated to any spontaneous motor activity changes. Responses to anti-depressant drugs are strongly modified in mice previously submitted to brain ischemia. Present results underline that not all antidepressant drugs are appropriate after ischemic stroke.

[A system of prescriptions without drug approval: example of baclofen]

Baclofen is an anti-spastic drug that acts as an agonist of GABA-B receptors. It also seems to decrease the appetence for alcohol (anti-craving effect), although this effect has not been certified by Authorities for drug approval in France (AMM). However, baclofen receives a great deal of demand by patients hoping to reduce their alcohol consumption. Nonetheless, the lack of AMM and the high doses of baclofen supposed to exert an anti-craving effect often discourage practitioners from prescribing this drug in current medical practice. Therefore, it is preferable for a drug like baclofen to be prescribed under specific regulations. As such, certain criteria similar to those required in clinical trials are necessary to protect patients as well as the prescribing doctors. The criteria that are proposed here are: the use of drugs without AMM approval as a last resort (all other treatments must have failed), the collegiate decision for the drug prescription, good knowledge of the potency of the drug as well as good record keeping of patients and proper supervision. The departments of addiction, pharmacology and pharmacovigilance of the University Hospital of Lille, France present here a medical process named "multidisciplinary consultations for resort treatments of addictions" (CAMTEA). This process is designed to meet all the above mentioned criteria and to allow the use of baclofen as an anti-craving drug in safest conditions. If this proves to be successful with baclofen, it is possible to extend the use of CAMTEA to other drugs without AMM approval in addictologic pathologies.

Postconditioning in focal cerebral ischemia: role of the mitochondrial ATP-dependent potassium channel

INTRODUCTION

Ischemic postconditioning (IpostC) has been described in both heart and brain. The first aim of this study was to evaluate the effects of IpostC on brain infarct size and neurological function in the middle cerebral artery occlusion (MCAO) model. The second aim was to determine the involvement of the mitochondrial potassium ATP-dependent channel (mitoK(ATP)) opening and its capacity to improve mitochondrial dysfunction induced by ischemia-reperfusion.

METHODS

Wistar rats were subjected to 60min MCAO followed by 24-h reperfusion. Postconditioning was performed by 3 cycles of 30-s occlusion-reperfusion at the onset of reperfusion. Three behavioral tests were performed following 24h of reperfusion. Involvement of mitoK(ATP) was determined by the modulation of IpostC effects by 5-hydroxydecanoate (5-HD) and diazoxide. Mitochondrial function after 24h of reperfusion on isolated mitochondria was assessed through mitochondrial oxygen consumption, mitochondrial membrane potential and calcium retention capacity to evaluate impact of IpostC on mitochondrial permeability transition pore (MPTP) opening.

RESULTS

IpostC resulted in a 40% decrease in infarct size and improved neurological outcome. These effects were lost when IpostC was delayed by 5min. The administration of diazoxide resulted in a 60% in infarct size. The beneficial effects of IpostC and diazoxide were blocked by 5-HD. Furthermore, 5-HD also blocked the inhibition of MPTP opening by IpostC and diazoxide. The hyperpolarization induced by ischemia-reperfusion was corrected by IpostC without any effect on oxidative phosphorylation.

CONCLUSION

Our results confirm ischemic postconditioning-induced neuroprotection. They also support the involvement of mitoK(ATP) opening and its role in inhibiting the opening of MTPT induced by postconditioning.

Biomarkers for the early stages of clinical development in Alzheimer's disease

As the failure of several recent Phase III drug development programmes bears witness, the clinical development of "disease-modifying" drugs in Alzheimer's disease has been confronted with challenging methodological difficulties. Taking into account the financial stakes involved taking drug candidates to the Phase III stage of development, and the risk of investing time and resources fruitlessly in the evaluation of poor candidate drugs, the crucial decision remains whether to proceed from Phase II to Phase III (Go/Nogo). The aim of Phase II studies is to select a molecule likely to be effective in Phase III, but also to eliminate candidate-drugs with an inadequate effect. No consensus currently exists on the best possible design of Phase II studies to inform the Go/Nogo decision optimally. The challenges in choosing the best study design relate to the target population, the end-point criteria used, in particular the use of biomarkers, the experimental protocol, and the study duration. The objective of the Round Table (RT) was to gather the opinions of French experts from the academic, industrial, and regulatory world in order to arrive at a consensus recommendation for the best possible design to be used in Phase II studies in Alzheimer's disease.

What are the causes of pre-existing dementia in patients with intracerebral haemorrhages?

In intracerebral haemorrhage, the most frequent underlying vasculopathies are cerebral amyloid angiopathy and hypertensive vasculopathy. Although both are associated with cognitive impairment, no study has focused on pre-existing dementia in patients with intracerebral haemorrhage. Therefore, we aimed to determine prevalence and mechanisms of pre-existing dementia in a large cohort of patients with an intracerebral haemorrhage. In a cohort of 417 patients, we evaluated the cognitive status before intracerebral haemorrhage with the Informant Questionnaire on Cognitive Decline in the Elderly. The cut-off to diagnose cognitive impairment with no dementia was 53 and 64 for pre-existing dementia. We determined factors associated with pre-existing dementia in multivariate analyses in the overall cohort and among patients with lobar only or deep only intracerebral haemorrhages. We performed post-mortem examinations when possible. Of 417 patients (median age 72 years, interquartile range 58-79), 58 (14%; 95% CI 11-18%) patients had cognitive impairment with no dementia and 65 had pre-existing dementia (16%; 95% CI 12-19%). In lobar intracerebral haemorrhage, the prevalence was 23%, and factors associated with pre-existing dementia were increasing age (odds ratio: 1.09 per year; 95% CI 1.02-1.15), having <8 years of education (odds ratio: 8.37; 95% CI 1.91-36.65) and increasing cortical atrophy (odds ratio: 3.34 per step; 95% CI 1.40-7.96). The five autopsied patients had Alzheimer's disease with cerebral amyloid angiopathy. In deep intracerebral haemorrhage, factors associated with pre-existing dementia were presence of old territorial vascular lesions (odds ratio: 4.52; 95% CI 1.18-17.42) and increasing severity of leucoaraiosis (odds ratio: 4.11 per step; 95% CI 1.73-9.75); the autopsied patient had small-vessel disease without Alzheimer's disease. These findings support the fact that pre-existing dementia is frequent in patients with intracerebral haemorrhage and may be the consequence of two different mechanisms: neurodegeneration with Alzheimer's disease and cerebral amyloid angiopathy in lobar intracerebral haemorrhage versus vascular process in deep intracerebral haemorrhage. These findings may contribute to the improvement of prevention and management of patients with intracerebral haemorrhages.