Functional proteomics related to energy metabolism of synaptosomes from different neuronal systems of rat hippocampus during aging.

The effect of aging on hippocampus is often confounded by diseases that commonly occur in the elderly. In this research, functional proteomics was used to characterize age-related changes in energy metabolism of different neuronal pathways within the hippocampus of Wistar rats aged 2, 6, 12, 18, and 24 months. The "large" synaptosomes, derived from glutamatergic mossy fiber endings connecting granule cells of dentate gyrus with apical dendrites of CA3 pyramidal cells, and the "small" synaptosomes, derived from the cholinergic small nerve endings of septo-hippocampal fibers, whose projections reach CA1 pyramidal cells, were isolated. Because most brain disorders are associated with bioenergetic changes, the maximum rate (V(max)) of selected enzymes of glycolysis, Krebs cycle, glutamate and amino acids metabolism, and acetylcholine catabolism were evaluated. The results show that "large" and "small" synaptosomes possess specific and independent metabolic features coherently with the selective vulnerability of the respective hippocampal subfields to Alzheimer's disease and cerebral ischemia. This study represents a reliable model to study in vivo (i) the physiopathological molecular mechanisms of some brain diseases dependent on energy metabolism, (ii) the responsiveness to noxious stimuli, and (iii) the effects of drugs, discriminating their action sites at subcellular level.

Pharmacological therapy of acute ischaemic stroke: Achievements and problems.

Acute ischaemic stroke (AIS) is a leading cause of death and disability worldwide. Its incidence and prevalence increase considerably with age and numbers will grow with an ageing population. Consequently, the impact of AIS on costs is soaring. AIS is caused by the abrupt occlusion of an intracranial vessel resulting in reduced blood flow to the brain region supplied. The ischaemic core (which is irreversibly lesioned) is surrounded by the penumbra region with less severe flow reduction, lower functional impairment and potential recovery. Therefore, the fundamental treatment of AIS relies on prompt recanalisation and reperfusion of the threatened, but potentially salvageable, ischaemic penumbra. With this aim, intravenous thrombolysis with recombinant tissue plasminogen activator (rtPA) remains the current strategy. However, thrombolysis is underused, owing to various exclusion criteria that limit the number of treated patients. Other thrombolytics are under investigation. Endovascular therapy with mechanical recanalisation devices is also increasingly applied, though definite evidence of its benefit is lacking. Moreover, hypertension and hyperglycaemia are acute complications to be treated in AIS. This review analyses the current status, the problems, the perspectives and the cost-effectiveness of the pharmacological therapy for AIS.

Neuroprotection for ischaemic stroke: current status and challenges.

Stroke is the third cause of death worldwide and the main cause of chronic, severe adult disability. We focus on acute ischaemic stroke, which accounts for approximately 80% of all strokes. The current therapy aims at restoring cerebral blood flow within a narrow time window in order to prevent damaging the "penumbra" which surrounds the infarct core. Intravenous thrombolysis remains the fundamental treatment worldwide, though not ideal for various restrictions and complications, limiting to 10% or less the percentage of patients treated within the appropriate time window. Neuroprotection is an alternative or adjunct approach to thrombolysis, targeting cerebral parenchyma in the acute ischaemic phase. Furthermore, neurorepair attempts to restore neuronal function in the after-stroke phase in those patients (treated or untreated) with significant impairment. In the past decades, the efficacy and safety of numerous candidate neuroprotective agents were shown in various animal stroke models. However, in clinical trials, promising pre-clinical studies have not been translated into positive outcomes. Our review will analyse the possible reasons for this failure and the new approaches and recommendations to overcome it, as well as novel strategies targeting additional events in ischaemia cascade. The combination of thrombolysis with pharmacological and non-pharmacological neuroprotective approaches has also been tested. Finally, the neurorepair strategy will be described with special emphasis on the role of cell-based therapies and ischaemic conditioning. Hopefully, the future therapy of ischaemic stroke will encompass a combination of neuroprotection (to stabilise penumbra), thrombolysis, antithrombotics (for secondary prevention) and neurorepair based on cell therapy plus rehabilitation.

Structural damage induced by peroxidation may account for functional impairment of heavy synaptic mitochondria.

Coenzyme Q distribution, as well as respiratory chain features, in rat brain mitochondria depend on mitochondrial subpopulation, brain region and age. Heavy mitochondria (HM) usually display the lowest content of respiratory components and the lowest enzymatic activities and it has been suggested that they represent the oldest mitochondrial population. In this study, we confirmed that HM are considerably compromised in their structure. In fact, HM showed to have the highest hydroperoxide content and the most consistent modifications in their fatty acid pattern with wide loss of fatty acids (or part of them) in the phospholipid moiety. Such situation could explain the typical impairment of HM and could support the hypothesis that they represent an old mitochondrial population.