PPARs: a potential target for a disease-modifying strategy in stroke

Stroke is one of the major causes of mortality and disability in adults in industrialized countries. Despite numerous preclinical studies and clinical trials in the field of cerebral ischemia, no pharmacological agent has been validated in the treatment of acute ischemic, except thrombolysis. Cerebral ischemia is not only a neuronal disease but it affects the entire neurovascular unit. The therapeutic strategy in stroke should be more global and combine preventive approaches, acute phase treatment and long-term care to improve recovery and prevent or treat affective and cognitive post-stroke consequences. There is an imperative need to develop disease-modifying drugs, which should be able to induce neuroprotection, to serve as adjuvants for thrombolysis by decreasing the hemorrhagic risk and to limit the long-term post-stroke consequences. This review presents the potential effects of Peroxisome Proliferator-Activated Receptors (PPARs) and of their agonists in stroke. We focus on each PPAR receptor and detail their implication in stroke. PPARs are nuclear receptors, acting as ligand-dependent transcription factors. They are expressed in the neurovascular unit that suggests that PPARs could play a role in stroke. Indeed, it has been shown that they are able to interfere with pathways implicated in the pathophysiology of stroke. They could be an answer to this disease-modifying drug concept, being able to act on the different phases of ischemia.

Therapeutic prospects of PPARs in psychiatric disorders: a comprehensive review

Peroxisome Proliferator-Activated Receptors (PPARs) are a family of nuclear receptors whose activation modulates the gene expression that underlies both the glucid-lipid and the inflammation pathways. While many PPARs agonists have been used for years as medication for metabolic disorders, an increasing attention is being currently dedicated to these drugs for inflammation-related pathologies. Within the psychiatric field, it has recently appeared that inflammatory processes are highly suspected in the pathophysiology of several important disorders, such as schizophrenia and mood disorders. By their anti-inflammatory properties, PPARs might have a disease-modifying action that could help in improving the outcome of patients. Furthermore, recent data suggest that PPARs could also modulate the expression of some neurotransmission factors. Therefore, PPARs may directly modify the information processing, and have a potential symptomatic action on several psychiatric disorders. At last, PPARs action of metabolic regulation could have a role on corrective or even preventive strategies against the metabolic adverse events that are commonly observed with some current psychiatric medications, notably antipsychotics. This triple potential action profile of PPARs modulators is investigated in this article, successively for schizophrenia spectrum disorders and mood disorders. Theoretical involvements of PPARs are also discussed for the treatment of Post- Traumatic Stress Disorder and Personality Disorders. At the time of the emerging concept of psychoneuroimmunology, PPARs open original therapeutic prospects for the psychiatric research.

IV thrombolysis and renal function

OBJECTIVE

To investigate the association of renal impairment on functional outcome and complications in stroke patients treated with IV thrombolysis (IVT).

METHODS

In this observational study, we compared the estimated glomerular filtration rate (GFR) with poor 3-month outcome (modified Rankin Scale scores 3-6), death, and symptomatic intracranial hemorrhage (sICH) based on the criteria of the European Cooperative Acute Stroke Study II trial. Unadjusted and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Patients without IVT treatment served as a comparison group.

RESULTS

Among 4,780 IVT-treated patients, 1,217 (25.5%) had a low GFR (<60 mL/min/1.73 m(2)). A GFR decrease by 10 mL/min/1.73 m(2) increased the risk of poor outcome (OR [95% CI]): (ORunadjusted 1.20 [1.17-1.24]; ORadjusted 1.05 [1.01-1.09]), death (ORunadjusted 1.33 [1.28-1.38]; ORadjusted 1.18 [1.11-1.249]), and sICH (ORunadjusted 1.15 [1.01-1.22]; ORadjusted 1.11 [1.04-1.20]). Low GFR was independently associated with poor 3-month outcome (ORadjusted 1.32 [1.10-1.58]), death (ORadjusted 1.73 [1.39-2.14]), and sICH (ORadjusted 1.64 [1.21-2.23]) compared with normal GFR (60-120 mL/min/1.73 m(2)). Low GFR (ORadjusted 1.64 [1.21-2.23]) and stroke severity (ORadjusted 1.05 [1.03-1.07]) independently determined sICH. Compared with patients who did not receive IVT, treatment with IVT in patients with low GFR was associated with poor outcome (ORadjusted 1.79 [1.41-2.25]), and with favorable outcome in those with normal GFR (ORadjusted 0.77 [0.63-0.94]).

CONCLUSION

Renal function significantly modified outcome and complication rates in IVT-treated stroke patients. Lower GFR might be a better risk indicator for sICH than age. A decrease of GFR by 10 mL/min/1.73 m(2) seems to have a similar impact on the risk of death or sICH as a 1-point-higher NIH Stroke Scale score measuring stroke severity.

Validation of the DRAGON Score in 12 Stroke Centers in Anterior and Posterior Circulation

Background and Purpose—

The DRAGON score predicts functional outcome in the hyperacute phase of intravenous thrombolysis treatment of ischemic stroke patients. We aimed to validate the score in a large multicenter cohort in anterior and posterior circulation.

Methods—

Prospectively collected data of consecutive ischemic stroke patients who received intravenous thrombolysis in 12 stroke centers were merged (n=5471). We excluded patients lacking data necessary to calculate the score and patients with missing 3-month modified Rankin scale scores. The final cohort comprised 4519 eligible patients. We assessed the performance of the DRAGON score with area under the receiver operating characteristic curve in the whole cohort for both good (modified Rankin scale score, 0–2) and miserable (modified Rankin scale score, 5–6) outcomes.

Results—

Area under the receiver operating characteristic curve was 0.84 (0.82–0.85) for miserable outcome and 0.82 (0.80–0.83) for good outcome. Proportions of patients with good outcome were 96%, 93%, 78%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 2%, 4%, 89%, and 97% for 0 to 1, 2, 3, 8, and 9 to 10 points, respectively. When tested separately for anterior and posterior circulation, there was no difference in performance ( P =0.55); areas under the receiver operating characteristic curve were 0.84 (0.83–0.86) and 0.82 (0.78–0.87), respectively. No sex-related difference in performance was observed ( P =0.25).

Conclusions—

The DRAGON score showed very good performance in the large merged cohort in both anterior and posterior circulation strokes. The DRAGON score provides rapid estimation of patient prognosis and supports clinical decision-making in the hyperacute phase of stroke care (eg, when invasive add-on strategies are considered).

Off-label prescriptions: how to identify them, frame them, announce them and monitor them in practice?

Following the Mediator crisis and the passage of the Health and Safety Law of December 2011, off-label prescriptions are a real concern shared by all those involved in healthcare system. Off-label, in the strictest sense of the term, is defined as all prescriptions that do not correspond to the summary of product characteristics (SPC), particularly those that fail to comply with the indications and dosage regimens defined by the marketing authorization (MA) for clear safety reasons. There are various rasons for off-label prescriptions, both conscious and unconscious. They are intended to respond to unmet medical needs, the needs of poorly studied populations or not studied at all in trials, but in relation to whom it is reasonable to extrapolate that MA would be given (common-sense prescriptions) and, additionally, to urgent public health needs (such as baclofen, pregnant women, and HIV drugs). All these prescriptions would deserve to be studied for a potential MA. However, there are off-label prescriptions that need to be restricted or even penalized in the case of compassionate prescriptions or unjustified prescriptions or prescriptions not based on any scientific grounds. Off-label prescriptions are not easy to track down because if the prescriber has to write "off-label" on his prescription, then clearly, in practice, he will only do so in exceptional cases. Neither the pharmacists who dispense the drug nor the Social Security that reimburses it, have access to the diagnosis (or targeted indication). Thus, in order to identify the off-label prescription, we must be able to cross reference the available databases (such as pharmacovigilance database, medicalized information system program [programme de médicalisation des systèmes d'information, PMSI], hospital drug formularies, general sample of beneficiaries [échantillon généraliste de bénéficiaires, EGB] or national inter-regional Health Insurance Information System [système national d'informations inter-régions d'Assurance maladie, SNIIRAM], sales data, and data from market surveys). The shared computerized patient file may resolve this problem. The temporary use recommendation (TUR) proposed by the Drug Safety Law will only partially deal with this problem for recently marketed molecules. This temporary and exceptional mechanism will authorize a recognized off-label prescription, which may be reimbursed and monitored for 3 years. These TURs will only concern a small portion of "off-label" drugs having yet a positive risk/benefit ratio (conditional MA) but this is far from matching with majority of off-label prescriptions. As such, and in order to improve the use of drugs, it is important to propose a control system for all "off-label" prescriptions with a dedicated committee: the "off-label" committee which would determine the frame of the "off-label" prescriptions.

PPARα is involved in the multitargeted effects of a pretreatment with atorvastatin in experimental stroke

There is now substantial data in the literature showing that statins can protect against cerebral ischemia. This neuroprotective potency is related to their pleiotropic effects that modulate various pathways implicated in the pathophysiology of stroke. It has been demonstrated that statins exert anti-inflammatory and vasculoprotective effects, thus contributing to a reduction in infarct size. The underlying mechanisms are still incompletely known. As a cross-talk between statins and the nuclear receptor PPARα has been described, we hypothesized that this cross-talk is necessary to neuroprotection in stroke. We studied the effects of a 14-day preventive atorvastatin treatment (10 mg/kg/day) on C57Bl6 wild-type and PPARα-KO mice submitted to experimental stroke. PPARα was involved in the atorvastatin-induced neuroprotective effect, as confirmed by the measurement of infarct volumes. We also evidenced that the anti-inflammatory action of atorvastatin is mediated, at least partly, by PPARα. The decrease in IL-6 plasmatic levels was PPARα dependent. The cerebral expression of the adhesion molecules ICAM-1 and vascular cell adhesion molecule was reduced by the atorvastatin treatment, and this effect was PPARα dependent in the cortex but not in the striatum of treated animals. Atorvastatin also diminished the cerebral expression of iNOS in the cortex, but had no effect in the striatum of treated mice, whatever the PPARα status. At the vascular level, we found that the atorvastatin-related endothelial nitric oxide synthase upregulation was regulated by PPARα in the aorta, while there was no effect in the brain. We demonstrate here that PPARα is a key mediator of the multitargeted neuroprotective effects of statins in stroke.

Memantine for axial signs in Parkinson's disease: a randomised, double-blind, placebo-controlled pilot study

BACKGROUND

Given that memantine is thought to decrease N-methyl-D-aspartic-acid-related (NMDA) glutamatergic hyperactivity and improve locomotion in rats, we sought to assess the drug's impact on axial symptoms in advanced Parkinson's disease (PD).

METHODS

We performed a 90-day, randomised, double-blind, study with two parallel arms: 20 mg/day memantine versus placebo (ClinicalTrials.gov:NCT01108029). The main inclusion criterion was the presence of a severe gait disorder and an abnormal, forward-leaning stance. The following parameters were analysed under standardised conditions before and after acute administration of L-dopa: gait (stride length as primary criterion), the United-Parkinson's-Disease-Rating-Scale (UPDRS) motor score and its axial subscore, the hypertonia and strength of the axial extensors and flexors (isokinetic dynamometer), the Dyskinesia Rating Scale score (DRS) and its axial subscore.

RESULTS

Twenty-five patients were included. The memantine and placebo group did not differ significantly in terms of stride length. However, in the memantine group, we observed significantly better results (vs placebo) for the overall UPDRS score (F(1,21)=4.9; p=0.039(-1)) and its axial subscore (F(1,21)=7.2; p=0.014(-1.1)), axial hypertonia, the axial and overall DRS and axial strength.

CONCLUSIONS

Memantine treatment was associated with lower axial motor symptom and dyskinesia scores but did not improve gait. These benefits must be confirmed in a broader population of patients.

A very early neurological improvement after intravenous thrombolysis for acute cerebral ischaemia does not necessarily predict a favourable outcome

In patients treated by intravenous (i.v.) thrombolytic therapy for cerebral ischaemia, a very early neurological improvement (VENI) [National Institutes of Health Stroke Scale score (NIHSSS) 0, or early improvement ≥5 points], predicts a favourable outcome. VENI patients are usually excluded from trials testing complementary strategies, but a few of them have bad outcomes. To determine why VENI patients may have bad outcomes, we analysed the reasons for bad outcomes [modified Rankin Scale (mRS) score 2-6 at 3 months] in consecutive VENI patients. Of 365 consecutive patients with a pre-stroke mRS 0-1 (185 men, median age 69 years, median NIHSSS 12, median onset-to-needle time 147 min), 71 (19.5 %) had VENI. They were more likely to have had recent transient ischaemic attacks (OR 3.64, 95 % CI 1.08-12.27), higher baseline NIHSSS (median 14 vs. 11, p = 0.003) and shorter onset-to-needle times (median 135 min vs. 151, p = 0.01), and they were less likely to develop pneumonia (OR 0.27, 95 % CI 0.09-0.76) or malignant infarction (p = 0.045). In the 21 VENI patients (29.6 %) with a mRS 2-6 at 3-months, bad outcomes were due to the residual deficit in 14, secondary worsening of ischaemia in 4, intracranial haemorrhage in 2, and death from cancer in 1. One-third of VENI patients have bad outcomes, due to the residual neurological deficit in most of them. This finding suggests that VENI patients who still have a significant neurological deficit 1 h after thrombolysis should not be excluded from trials testing complementary strategies.

Mortality in patients treated by intra-venous thrombolysis for ischaemic stroke

In patients treated by intravenous (i.v.) thrombolysis, mortality rates range from 10 to 20 % at 3 months. The objective of this study was to determine the timing, causes and predictors of early (within 7 days) and delayed (8 days to 3 months) death after i.v. thrombolysis for cerebral ischaemia. We analyzed timing, causes and predictors of early and delayed mortality in a hospital-based registry of consecutive patients treated by i.v. thrombolysis for cerebral ischaemia. Of 500 patients (246 men; median age 71 years; median baseline National Institutes of Health Stroke Scale score 12; median onset-to-needle time 148 min), 76 (15.2%; 95% confidence interval [CI]: 12.3-18.6%) died within 3 months. Of 29 patients with early death, 21 (72.4%; 95% CI: 54.3-85.3%) died from neurovascular causes. Factors independently associated with early death were neurological complications and having had transient ischaemic attacks within the last 7 days. Of 47 patients with delayed death, 24 (51.1%; 95 % CI: 37.2-64.7%) died from infection, all but 1 having a modified Rankin scale >4 at 7 days. Factors independently associated with delayed death were pre-existing conditions and infections. Early and delayed mortality in ischaemic stroke patients are is highly dependent on the neurological status and response to thrombolysis. The target for reducing mortality is therefore to improve response to thrombolysis by any means, which can currently be achieved only by reducing delays.

Personalized Medicine: how to Switch from the Concept to the Integration into the Clinical Development Plan to Obtain Marketing Authorization

One of the challenges of the coming years is to personalize medicine in order to provide each patient with an individualized treatment plan. The three objectives of personalized medicine are to refine diagnosis, rationalize treatment and engage patients in a preventive approach. Personalization can be characterized by various descriptors whether related to the field, biology, imaging, type of lesion of the entity to be treated, comorbidity factors, coprescriptions or the environment As part of personalized medicine focused on biological markers including genetics or genomics, the integration of the clinical development plan to obtain marketing authorization may be segmented in 3 stages with a known descriptor identified before clinical development, a known descriptor discovered during clinical development or a known descriptor known after clinical development. For each stage, it is important to clearly define the technical optimization elements, to specify the expectations and objectives, to examine the methodological aspects of each clinical development phase and finally to consider the fast changing regulatory requirements in view of the few registered therapeutics complying with the definition of personalized medicine as well as the significant technological breakthroughs according to the screened and selected biomarkers. These considerations should be integrated in view of the time required for clinical development from early phase to MA, i.e. more than 10 years. Moreover, business models related to the economic environment should be taken into account when deciding whether or not to retain a biomarker allowing the selection of target populations in a general population.

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.