Telocytes in their context with other intercellular communication agents.

The past decade has borne witness to an explosion in our understanding of the fundamental complexities of intercellular communication. Previously, the field was solely defined by the simple exchange of endocrine, autocrine and epicrine agents. Then it was discovered that cells possess an elaborate system of extracellular vesicles, including exosomes, which carry a vast array of small and large molecules (including many epigenetic agents such as a variety RNAs and DNA), as well as large organelles that modulate almost every aspect of cellular function. In addition, it was thought that electrical communication between cells was limited mainly to neurotransmitters and neuromodulators in the nervous system. Also within the past decade, it was found that - in addition to neurons - most cells (both mammalian and non-mammalian) communicate via elaborate bioelectric systems which modulate many fundamental cellular processes including growth, differentiation, morphogenesis and repair. In the nervous system, volume transmission via the extracellular matrix has been added to the list. Lastly, it was discovered that what had previously been regarded as simple connective cells in most tissues proved to be miniature communication devices now known as telocytes. These unusually long, tenuous and sinuous cells utilize elaborate electrical, chemical and epigenetic mechanisms, including the exchange of exosomes, to integrate many activities within and between nearly all types of cells in tissues and organs. Their interrelationship with neural stem cells and neurogenesis in the context of neurodegenerative disease is just beginning to be explored. This review presents an account of precisely how each of these varied mechanisms are relevant and critical to the understanding of what telocytes are and how they function.

Safety and efficacy of Cerebrolysin in early post-stroke recovery: a meta-analysis of nine randomized clinical trials.

This meta-analysis combines the results of nine ischemic stroke trials, assessing efficacy of Cerebrolysin on global neurological improvement during early post-stroke period. Cerebrolysin is a parenterally administered neuropeptide preparation approved for treatment of stroke. All included studies had a prospective, randomized, double-blind, placebo-controlled design. The patients were treated with 30-50 ml Cerebrolysin once daily for 10-21 days, with treatment initiation within 72 h after onset of ischemic stroke. For five studies, original analysis data were available for meta-analysis (individual patient data analysis); for four studies, aggregate data were used. The combination by meta-analytic procedures was pre-planned and the methods of synthesis were pre-defined under blinded conditions. Search deadline for the present meta-analysis was December 31, 2016. The nonparametric Mann-Whitney (MW) effect size for National Institutes of Health Stroke Scale (NIHSS) on day 30 (or 21), combining the results of nine randomized, controlled trials by means of the robust Wei-Lachin pooling procedure (maximin-efficient robust test), indicated superiority of Cerebrolysin as compared with placebo (MW 0.60, P < 0.0001, N = 1879). The combined number needed to treat for clinically relevant changes in early NIHSS was 7.7 (95% CI 5.2 to 15.0). The additional full-scale ordinal analysis of modified Rankin Scale at day 90 in moderate to severe patients resulted in MW 0.61 with statistical significance in favor of Cerebrolysin (95% CI 0.52 to 0.69, P = 0.0118, N = 314). Safety aspects were comparable to placebo. Our meta-analysis confirms previous evidence that Cerebrolysin has a beneficial effect on early global neurological deficits in patients with acute ischemic stroke.

Safety and efficacy of Cerebrolysin in motor function recovery after stroke: a meta-analysis of the CARS trials.

This meta-analysis combines the results of two identical stroke studies (CARS-1 and CARS-2) assessing efficacy of Cerebrolysin on motor recovery during early rehabilitation. Cerebrolysin is a parenterally administered neuropeptide preparation approved for the treatment of stroke. Both studies had a prospective, randomized, double-blind, placebo-controlled design. Treatment with 30 ml Cerebrolysin once daily for 3 weeks was started 24-72 h after stroke onset. In addition, patients participated in a standardized rehabilitation program for 21 days that was initiated within 72 h after stroke onset. For both studies, the original analysis data were used for meta-analysis (individual patient data analysis). The combination of these two studies by meta-analytic procedures was pre-planned, and the methods were pre-defined under blinded conditions. The nonparametric Mann-Whitney (MW) effect size of the two studies on the ARAT score on day 90 indicated superiority of Cerebrolysin compared with placebo (MW 0.62, P < 0.0001, Wei-Lachin pooling procedure, day 90, last observation carried forward; N = 442). Also, analysis of early benefit at day 14 and day 21 by means of the National Institutes of Health Stroke Scale, which is regarded as most sensitive to early improvements, showed statistical significance (MW 0.59, P < 0.002). The corresponding number-needed-to-treat (NNT) for clinically relevant changes in early NIHSS was 7.1 (95% CI: 4 to 22). Cerebrolysin had a beneficial effect on motor function and neurological status in early rehabilitation patients after acute ischemic stroke. Safety aspects were comparable to placebo, showing a favourable benefit/risk ratio.

Intracranial cysts: an imagery diagnostic challenge.

Intracerebral cysts and cystic appearing intracerebral masses are common findings at routine cerebral imaging examination. We discuss here the most interesting aspects of some intracerebral cysts encountered in medical practice in terms of imaging, clinical and pathological description, and problems of differential diagnosis. On an almost routine basis, the neurologists have to deal with such differentials. Therefore, we aim to mention here some of the frequently encountered diagnosis problems when a patient presents with a cystic cerebral mass.

Platelet-derived growth factor receptor-ß-positive telocytes in skeletal muscle interstitium.

Telocytes (TCs) represent a new cell type recently described in mammalian skeletal muscle interstitium as well as in other organs. These have a specific morphology and phenotype, both in situ and in vitro. Telocytes are cells with long and slender cell prolongations, in contact with other interstitial cells, nerve fibres, blood capillaries and resident stem cells in niches. Our aim was to investigate the potential contribution of TCs to micro-vascular networks by immunofluorescent labelling of specific angiogenic growth factors and receptors. We found that in human skeletal muscle TCs were constantly located around intermediate and small blood vessels and endomysial capillaries. Epi-fluorescence and laser confocal microscopy showed that TCs express c-kit, platelet-derived growth factor receptor (PDGFR)-ß and VEGF, both in situ and in vitro. Telocytes were constantly located in the perivascular or pericapillary space, as confirmed by double staining of c-kit/CD31, PDGFR-ß/CD31 and PDGFR-ß/α-smooth muscle actin, respectively. Electron microscopy (EM) differentiated between pericytes and other cell types. Laminin labelling showed that TCs are not enclosed or surrounded by a basal lamina in contrast to mural cells. In conclusion, a) PDGFR-ß could be used as a marker for TCs and b) TCs are presumably a transitional population in the complex process of mural cell recruitment during angiogenesis and vascular remodelling.

Neuroregeneration in neurodegenerative disorders.

BACKGROUND: Neuroregeneration is a relatively recent concept that includes neurogenesis, neuroplasticity, and neurorestoration--implantation of viable cells as a therapeutical approach. DISCUSSION: Neurogenesis and neuroplasticity are impaired in brains of patients suffering from Alzheimer's Disease or Parkinson's Disease and correlate with low endogenous protection, as a result of a diminished growth factors expression. However, we hypothesize that the brain possesses, at least in early and medium stages of disease, a "neuroregenerative reserve", that could be exploited by growth factors or stem cells-neurorestoration therapies. SUMMARY: In this paper we review the current data regarding all three aspects of neuroregeneration in Alzheimer's Disease and Parkinson's Disease.

Altered expression of claudin family proteins in Alzheimer's disease and vascular dementia brains.

Claudins (Cls) are a multigene family of transmembrane proteins with different tissue distribution, which have an essential role in the formation and sealing capacity of tight junctions (TJs). At the level of the blood-brain barrier (BBB), TJs are the main molecular structures which separate the neuronal milieu from the circulatory space, by a restriction of the paracellular flow of water, ions and larger molecules into the brain. Different studies suggested recently significant BBB alterations in both vascular and degenerative dementia types. In a previous study we found in Alzheimer's disease (AD) and vascular dementia (VaD) brains an altered expression of occludin, a molecular partner of Cls in the TJs structure. Therefore in this study, using an immunohistochemical approach, we investigated the expression of Cl family proteins (Cl-2, Cl-5 and Cl-11) in frontal cortex of aged control, AD and VaD brains. To estimate the number of Cl-expressing cells, we applied a random systematic sampling and the unbiased optical fractionator method. We found selected neurons, astrocytes, oligodendrocytes and endothelial cells expressing Cl-2, Cl-5 and Cl-11 at detectable levels in all cases studied. We report a significant increase in ratio of neurons expressing Cl-2, Cl-5 and Cl-11 in both AD and VaD as compared to aged controls. The ratio of astrocytes expressing Cl-2 and Cl-11 was significantly higher in AD and VaD as compared to aged controls. The ratio of oligodendrocytes expressing Cl-11 was significantly higher in AD and the ratio of oligodendrocytes expressing Cl-2 was significantly higher in VaD as compared to aged controls. Within the cerebral cortex, Cls were selectively expressed by pyramidal neurons, which are the ones responsible for cognitive processes and affected by AD pathology. Our findings suggest a new function of Cl family proteins which might be linked to response to cellular stress.

A pilot study to evaluate the effects of Cerebrolysin on cognition and qEEG in vascular dementia: cognitive improvement correlates with qEEG acceleration.

The effects of the neurotrophic compound Cerebrolysin (Cere) on cognitive performance, evaluated with the ADAS-cog, and on qEEG activity were investigated in forty one patients with mild to moderate severe probable vascular dementia (VaD) according to NINDS-AIREN criteria, included in a placebo-controlled pilot study. Patients received i.v. infusions of Cere (10 or 30 ml) or placebo (normal saline) 5 days/week for 4 weeks. Mean score of change from baseline in the ADAS-cog and percent change from baseline in slow to fast EEG power ratio (PR) scores were the two primary endpoints. Correlations between cognition and qEEG were also evaluated for both baseline scores and for scores of change from baseline in ADAS-cog and in qEEG parameters, including EEG power ratio (PR) as an index of EEG slowing. Baseline ADAS-cog scores showed significant positive correlations with delta power, theta power and PR scores, and correlated negatively with alpha activity. These correlations indicating that an increased EEG slowing is associated with a worst cognitive performance in VaD patients. Cere treatment improved cognitive performance significantly at the 10 ml dose and reduced EEG slowing with both 10 and 30 ml dosages. A significant positive correlation between PR and ADAS-cog scores of change from baseline was observed in Cere-treated patients. According to results of this pilot study, it is concluded that Cere improves cognitive performance and reduces EEG slowing in patients with VaD, and that there is a positive relationship between changes in cognition and qEEG activity induced by Cere. The conduction of further regular clinical trials is required to confirm the potential utility of Cere in the treatment of VaD suggested by the present results.

Myokines as Possible Therapeutic Targets in Cancer Cachexia.

Cachexia is an extremely serious syndrome which occurs in most patients with different cancers, and it is characterized by systemic inflammation, a negative protein and energy balance, and involuntary loss of body mass. This syndrome has a dramatic impact on the patient's quality of life, and it is also associated with a low response to chemotherapy leading to a decrease in survival. Despite this, cachexia is still underestimated and often untreated. New research is needed in this area to understand this complex phenomenon and ultimately find treatment methods and therapeutic targets. The skeletal muscle can act as an endocrine organ. Signaling between muscles and other systems is done through myokines, cytokines, and proteins produced and released by myocytes. In this review, we would like to draw attention to some of the most important myokines that could have potential as biomarkers and therapeutic targets: myostatin, irisin, myonectin, decorin, fibroblast growth factor 21, interleukin-6, interleukin-8, and interleukin-15.

Presenilin-mediated signal transduction.

Presenilin proteins, mutated forms of which cause early onset familial Alzheimer's disease, are capable of modulating various cell signal transduction pathways, the most extensively studied of which has been intracellular calcium signalling. Disease causing presenilin mutations can potentiate inositol(1,4,5)trisphosphate (InsP3) mediated endoplasmic reticulum release due to calcium overload in this organelle, as well as attenuate capacitative calcium entry. Our own studies have shown a novel function for presenilins that involves regulation of acetylcholine muscarinic receptor-stimulated phospholipase C upstream of InsP3 regulated calcium release. This article reviews the mechanisms by which presenilins modulate intracellular calcium signalling and the role that deregulated calcium homeostasis could play in the pathogenesis of Alzheimer's disease.

MicroRNAs in CAG trinucleotide repeat expansion disorders: an integrated review of the literature.

MicroRNAs are small RNAs involved in gene silencing. They play important roles in transcriptional regulation and are selectively and abundantly expressed in the central nervous system. A considerable amount of the human genome is comprised of tandem repeating nucleotide streams. Several diseases are caused by above-threshold expansion of certain trinucleotide repeats occurring in a protein-coding or non-coding region. Though monogenic, CAG trinucleotide repeat expansion disorders have a complex pathogenesis, various combinations of multiple coexisting pathways resulting in one common final consequence: selective neurodegeneration. Mutant protein and mutant transcript gain of toxic function are considered to be the core pathogenic mechanisms. The profile of microRNAs in CAG trinucleotide repeat disorders is scarcely described, however microRNA dysregulation has been identified in these diseases and microRNA-related intereference with gene expression is considered to be involved in their pathogenesis. Better understanding of microRNAs functions and means of manipulation promises to offer further insights into the pathogenic pathways of CAG repeat expansion disorders, to point out new potential targets for drug intervention and to provide some of the much needed etiopathogenic therapeutic agents. A number of disease-modifying microRNA silencing strategies are under development, but several implementation impediments still have to be resolved. CAG targeting seems feasible and efficient in animal models and is an appealing approach for clinical practice. Preliminary human trials are just beginning.

Cardiovascular Dysfunction in Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic neurological condition, characterized by recurrent episodes of inflammation and demyelination of the central nervous system called relapsing-remitting episodes, and continuous axonal degeneration that leads to irreversible progressive invalidity. Patients with multiple sclerosis present a higher mortality rate compared to the general population, and the excess of mortality may be explained by the increased cardiovascular risk and occurrence of cardiovascular disease. However, the exact pathways to cardiovascular dysfunction are not yet completely elucidated. This review focuses on the most important mechanisms of cardiovascular dysfunction in MS, such as the cardiomyocite structure alteration, the cardiovascular autonomous nervous system dysfunction, physical invalidity, oxidative stress and endothelial dysfunction, as well as the impact of cardiovascular risk factors in MS. The latest evidence about therapeutic approaches for MS, such as immunomodulatory treatment, vitamin D supplementation and statins are also discussed. There is little knowledge about the cardiovascular dysfunction in MS, and further research is required to improve the understanding of these complex mechanisms.

Mechanisms of cell death in Alzheimer's disease: role of presenilins.

Presenilins are often mutated in familial forms of Alzheimer's disease (AD). Such mutations sensitize cells in culture to different apoptotic stimuli eg. staurosporine, calcium ionophore, growth factor withdrawal. The altered responses to apoptotic stimuli in cells carrying presenilin mutations include increased intracellular calcium concentrations and enhanced production of reactive oxygen species. Presenilin mutations also result in increased production of amyloid beta (Abeta) indicating that presenilins participate in the cleavage of amyloid beta-protein precursor (AbetaPP). In fact, presenilin is part of the gamma-secretase complex which together with beta-secretase cleaves AbetaPP and produce Abeta, later forming the senile plaques typical for AD pathology. Here we review the current knowledge about the mechanisms of cell death in AD with focus on the role of presenilin and presenilin mutations in apoptosis. It appears that presenilin and its different fragments, generated after proteolytic cleavage, have a regulatory role in apoptosis. In addition, different studies show that the cellular levels of presenilin are controlled by proteasomal degradation both under normal and stress conditions.

Oxidative stress in Alzheimer's disease: why did antioxidant therapy fail?

Alzheimer's disease (AD) is the most common form of dementia in the elderly, with increasing prevalence and no disease-modifying treatment available yet. A remarkable amount of data supports the hypothesis that oxidative stress is an early and important pathogenic operator in AD. However, all clinical studies conducted to date did not prove a clear beneficial effect of antioxidant treatment in AD patients. In the current work, we review the current knowledge about oxidative stress in AD pathogeny and we suggest future paths that are worth to be explored in animal models and clinical studies, in order to get a better approach of oxidative imbalance in this inexorable neurodegenerative disease.

Functional and molecular characterization of the effect of amyloid-ß42 on an in vitro epithelial barrier model.

Recently, the blood-brain barrier (BBB) has been pointed to as an active player in neurodegenerative disorders, albeit the actual succession of pathogenic events remains to be elucidated. Amyloid-ß (Aß) is an important pathogenic player in Alzheimer's disease, and it is cleared from the brain partly by transportation across the BBB. In this work we asked the question whether Aß-induced alteration of tight junction (TJ) protein expression is a result of the complex in situ microenvironment of the BBB or if it can be replicated in an externalized environment, such as an in vitro epithelial barrier, where barrier property changes can be investigated without confounding factors. Therefore, we treated barrier forming MDCKI and II epithelial cells with Aß42 and investigated TJ occludin and claudin-2 protein levels and cellular distribution through western blot and immunofluorescence. To assess barrier function, we measured transepithelial resistance (TEER) and studied cell polarity through atomic force microscopy (AFM). We found that Aß42 cell treatment increased occludin expression and decreased claudin-2 expression. With TEER, an increase in paracellular resistance was noted, which started at 10 hours and peaked at 20 hours of Aß42 treatment. AFM analysis demonstrated an associated morphological alteration of the cell monolayer. In conclusion, we demonstrated that Aß42 is able to modify TJ protein expression and to functionally alter barrier properties in vitro and that this effect is not conditioned by other pathogenic Alzheimer's disease events taking place in the complex brain microenvironment.

Label free sensing platform for amyloid fibrils effect on living cells.

This study presents a multiparametric label-free analysis gathering surface plasmon resonance (SPR) and electrical impedance spectroscopy (EIS) for monitoring the progress of a model epithelial cell culture (Madin Darbey Canine Kidney - MDCK) exposed to a peptide with high bio-medical relevance, amyloid ß (Aß42). The approach surpasses the limitations in using the SPR angle for analyzing confluent cell monolayers and proposes a novel quantitative analysis of the SPR dip combined with advanced EIS as a tool for dynamic cell assessment. Long, up to 48h time series of EIS and SPR data reveal a biphasic cellular response upon Aß42 exposure corresponding to changes in cell-substrate adherence, cell-cell tightening or cytoskeletal remodeling. The equivalent circuit used for fitting the EIS spectra provided substantiation of SPR analysis on the progress of cell adhesion as well as insight on dynamics of cell-cell junction. Complementary endpoint assays: western blot analysis and atomic force microscopy experiments have been performed for validation. The proposed label free sensing of nonlethal effect of model amyloid protein at cellular level provides enhanced resolution on cell-surface and cell-cell interactions modulated by membrane related protein apparatus, applicable as well to other adherent cell types and amyloid compounds.

Is there a causal link between inflammation and dementia?

Neuroinflammation is a constant event in Alzheimer's disease (AD), but the current knowledge is insufficient to state whether inflammation is a cause, a promoter, or simply a secondary phenomenon in this inexorably progressive ailment. In the current paper, we review research data showing that inflammation is not a prerequisite for onset of dementia, and, although it may worsen the course of the disease, recent evidence shows that chronic inhibition of inflammatory pathways is not necessarily beneficial for patients. Prospective clinical trials with anti-inflammatory drugs failed to stop disease progression, measurements of inflammatory markers in serum and cerebrospinal fluid of patients yielded contradictory results, and recent bench research proved undoubtedly that neuroinflammation has a protective side as well. Knockout animal models for TNFRs or ILRs do not seem to prevent the pathology or the cognitive decline, but quite the contrary. In AD, the therapeutic intervention on inflammatory pathways still has a research future, but its targets probably need reevaluation.

Triggers and effectors of oxidative stress at blood-brain barrier level: relevance for brain ageing and neurodegeneration.

As fundamental research advances, it is becoming increasingly clear that a clinically expressed disease implies a mixture of intertwining molecular disturbances. Oxidative stress is one of such pathogenic pathways involved in virtually all central nervous system pathologies, infectious, inflammatory, or degenerative in nature. Since brain homeostasis largely depends on integrity of blood-brain barrier (BBB), many studies focused lately on BBB alteration in a wide spectrum of brain diseases. The proper two-way molecular transfer through BBB depends on several factors, including the functional status of its tight junction (TJ) complexes of proteins sealing neighbour endothelial cells. Although there is abundant experimental work showing that oxidative stress associates BBB permeability alteration, less is known about its implications, at molecular level, in TJ protein expression or TJ-related cell signalling. In this paper, oxidative stress is presented as a common pathway for different brain pathogenic mechanisms which lead to BBB dysregulation. We revise here oxidative-induced molecular mechanisms of BBB disruption and TJ protein expression alteration, in relation to ageing and neurodegeneration.

Microemboli detection in patients with carotid artery stenting--a potential marker for future cognitive impairment?

AIMS: To monitor the long-term cognitive function evolution of patients undergoing carotid artery stenting (CAS), using detection of embolic signals (ES) as a potential marker of cognitive decline. METHODS: This is an ongoing prospective nonrandomized single-center study of patients undergoing carotid artery angioplasty and stenting using standard techniques. Neurologic status is evaluated by history, physical examination and the National Institutes of Health Stroke Scale. A complete Doppler-ultrasound investigation of the brain-supplying arteries has been performed in every patient. A 45minute cognitive battery designed to assess motor speed/coordination and executive function, psychomotor speed, language (naming), working memory/concentration, verbal fluency, and learning/memory is performed by a certified neuropsychologist in the first week after CAS and repeated a year after the procedure. Each patient undergoes bilateral ultrasonographic-Doppler monitoring of the middle cerebral artery (MCA) for microemboli detection. The patients are monitored during the first week after CAS and again a year after stenting. RESULTS: 32 patients were included. The mean baseline Mini-Mental State Examination (MMSE) score was 28.7 points. During the first ultrasonographic monitoring 28 patients (87.5%) had at least three times more ES detected on the stented side (a mean of 24ES/30minutes was detected in the stented side compared to a mean of 4ES/30min in the non-stented side). At the one-year follow-up 68% of the patients who have undergone CAS maintain a high number of ES detected in the territory of the stented carotid artery, finding that is well correlated with the cognitive decline in those patients, as assessed by the MMSE score. CONCLUSIONS: ES detection is a useful tool for predicting cognitive decline that can be used to monitor CAS patients and adjust preventive measures in order to avoid progression of vascular cognitive impairment. It is important that further studies comparing carotid endarterectomy and CAS monitor long-term cognitive function outcome.

Claudin expression profile separates Alzheimer's disease cases from normal aging and from vascular dementia cases.

We have reported earlier that tight-junction proteins are detectable by standard immunohistochemistry in the brain parenchyma, namely in the cell bodies of neurons, astrocytes, and oligodendrocytes. Here we show, by projection to latent structures - discriminate analysis (PLS-DA), that the immunohistochemical detection profile of tight junction proteins clearly distinguishes the AD cases from healthy aging controls and from the cases of dementia with a predominantly vascular pathology underlying the symptoms (vascular dementia, VaD; cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, CADASIL; and cerebral amyloid angiopathy, CAA). Our findings might be valuable in the perspective of developing biomarkers for AD.