Internal carotid artery fibromuscular dysplasia in arterial hypertension: Management in clinical practice

Fibromuscular dysplasia (FMD) reminds of a rare form of secondary arterial hypertension occurring in young people and involving the renal arteries. FMD may also involve vertebral, subclavian, mesenteric, iliac arteries and carotid arteries. FMD of internal carotid arteries is a rare finding that is frequently incidental and asymptomatic. It usually occurs in middle-aged women and is secondary to media-intima fibrodysplasia. The carotid artery may be elongated or kinked and associated cerebral aneurysms have been reported. Symptoms including transient ischaemic attack or stroke are uncommon and are related to decrease of blood flow or embolization by platelet aggregates. At the onset, differential diagnosis with vasculitis must be placed. Computed tomography or magnetic resonance imaging (MRI) angiography demonstrates bilateral high-grade stenosis with the characteristic "string of beads" pattern. Antiplatelet medication is the accepted therapy for asymptomatic lesions. Graduated endoluminal surgical dilation is an outmoded therapy, no longer used in most medical centres. Current percutaneous angioplasty is the preferred treatment for symptomatic carotid FMD, but no randomized controlled trials comparing this methodology with surgery is available. The management of a case of arterial systemic FMD in a 52-year-old women, diagnosed after a hypertensive crysis, is discussed. Imaging methods disclosed stenoses of carotid arteries, of celiac tripod and of superior mesenteric artery. Because of high risk associated to endovascular surgery, medical therapy was started. In the first year of follow-up, no events have been reported

Antihypertensive Treatment in the Elderly and Very Elderly: Always “the Lower, the Better?”

Arterial hypertension (HT) is age dependent and, with the prolongation of life expectancy, affects more and more elderly people. In the elderly, HT is a risk factor for organ damage and cardiovascular (CV) events. Both pharmacologic and nonpharmacologic reduction of blood pressure (BP) is associated with a corresponding decrease in systolic-diastolic or isolated systolic HT. Clinical trials have shown that BP lowering is associated with a decrease in stroke and other CV events. Therefore, BP reduction per se appears more important than a particular class of antihypertensive drugs. The benefit of antihypertensive treatment has been confirmed up to the age of 80 years, remaining unclear in the octogenarians. The benefit in lowering diastolic BP between 80 and 90 mmHg is well established, while that of lowering systolic BP below 140 mmHg requires further confirmations

On the Role of the Balance of GPCR Homo/ Heteroreceptor Complexes in the Brain

The early work on neuropeptide-monoamine receptor-receptor interactions in the Central Nervous System gave the first indications of the existence of G protein-coupled receptors (GPCRs) heteroreceptor complexes and the GPCR field began to expand from monomers into heteromers and higher order heteromers, including also GPCR-ion channel, Receptor Tyrosine Kinases (RTK)-GPCR and Receptor activity-modifying proteins-GPCR heteroreceptor complexes. The existence of heteroreceptor complexes with allosteric receptor-receptor interactions increases the diversity of receptor function including recognition, trafficking and signalling. We have proposed the molecular phenomenon of receptor-receptor interactions as a good way to understand of how brain function can increase through molecular integration of signals. An alteration in specific receptor-receptor interactions or their balance/equilibrium (with the corresponding monomers-homomers) are indeed considered to have a role in the pathogenic mechanisms that lead to various diseases, including drug addiction, depression, Parkinson's disease and schizophrenia. Therefore, targeting protomer-protomer interactions in heteroreceptor complexes or the balance with their corresponding homoreceptor complexes in discrete brain regions may become an important field for developing novel drugs, including heterobivalent drugs and optimal types of combined treatments. Increasing our understanding of molecular integration of signals via allosteric receptor-receptor interactions in the heteroreceptor complexes will have a major impact on the molecular medicine, leading to novel strategies for drug discovery and treatment of diseases

On the Role of the Balance of GPCR Homo/ Heteroreceptor Complexes in the Brain

The early work on neuropeptide-monoamine receptor-receptor interactions in the Central Nervous System gave the first indications of the existence of G protein-coupled receptors (GPCRs) heteroreceptor complexes and the GPCR field began to expand from monomers into heteromers and higher order heteromers, including also GPCR-ion channel, Receptor Tyrosine Kinases (RTK)-GPCR and Receptor activity-modifying proteins-GPCR heteroreceptor complexes. The existence of heteroreceptor complexes with allosteric receptor-receptor interactions increases the diversity of receptor function including recognition, trafficking and signalling. We have proposed the molecular phenomenon of receptor-receptor interactions as a good way to understand of how brain function can increase through molecular integration of signals. An alteration in specific receptor-receptor interactions or their balance/equilibrium (with the corresponding monomers-homomers) are indeed considered to have a role in the pathogenic mechanisms that lead to various diseases, including drug addiction, depression, Parkinson's disease and schizophrenia. Therefore, targeting protomer-protomer interactions in heteroreceptor complexes or the balance with their corresponding homoreceptor complexes in discrete brain regions may become an important field for developing novel drugs, including heterobivalent drugs and optimal types of combined treatments. Increasing our understanding of molecular integration of signals via allosteric receptor-receptor interactions in the heteroreceptor complexes will have a major impact on the molecular medicine, leading to novel strategies for drug discovery and treatment of diseases

Motor reinnervation during muscular activity

Motor reinnervation during muscular activity Sartini S, Bartolini F, Lattanzi D, Ciuffoli S, Ambrogini P, Cuppini R Dept. Human, Environmental, Natural Scieces, University of Urbino “Carlo Bo”, Italy. Following nerve injury and regeneration, a transient phase of multiple innervation of muscle cells occurs. Successively, 1:1 ratio of innervation is progressively reached. Two mechanisms has been proposed to explain these processes: nerve-terminal competition for muscle released growth factors and the different pattern of axon activity. We showed running to enhance muscle expression of BDNF, a trophic factor inducing sprouting. Thus we investigated the role of running early in post-traumatic reinnervation. We used intracellular recordings and miography to evaluate the reinnervation of soleus muscle following nerve crush, in running and sedentary rats. In sedentary rats, about 10% of recorded muscle cells was found to be multiply innervated from 7 to 45 days from nerve crush. In runners, multiple innervation reached 34% 10 days after nerve crush and this percentage gradually decreased during the following days, although it remained significantly higher with respect to sedentary group. This effect of running was reversible. Both in runner and sedentary rats all axons were showed to be regenerated 10 days after nerve crush, but in runners recovery of muscle strength was higher and muscle reinnervation was almost complete. On the basis of present results, we hypothesize that intense motoneuron-muscle activity might induce up-regulation of one or more neurotrophic factors released by muscle cells, that might induce motor nerve terminal sprouting and consequent massive muscle cell multiple innervation. This model allow to link nerve-terminal competition and axon activity hypotheses and is intriguing considering the importance of physical activity during rehabilitation and the correlated exercise protocol planning

A feature-based neurocomputational model of semantic memory

According with a featural organization of semantic memory, this work is aimed at investigating, through an attractor network, the role of different kinds of features in the representation of concepts, both in normal and neurodegenerative conditions. We implemented new synaptic learning rules in order to take into account the role of partially shared features and of distinctive features with different saliency. The model includes semantic and lexical layers, coding, respectively for object features and word-forms. Connections among nodes are strongly asymmetrical. To account for the feature saliency, asymmetrical synapses were created using Hebbian rules of potentiation and depotentiation, setting different pre-synaptic and post-synaptic thresholds. A variable post-synaptic threshold, which automatically changed to reflect the feature frequency in different concepts (i.e., how many concepts share a feature), was used to account for partially shared features. The trained network solved naming tasks and word recognition tasks very well, exploiting the different role of salient versus marginal features in concept identification. In the case of damage, superordinate concepts were preserved better than the subordinate ones. Interestingly, the degradation of salient features, but not of marginal ones, prevented object identification. The model suggests that Hebbian rules, with adjustable post-synaptic thresholds, can provide a reliable semantic representation of objects exploiting the statistics of input features

Physical exercise and environment exploration affect synaptogenesis in adult-generated neurons in the rat dentate gyrus: Possible role of BDNF.

A brief training in a pool maze, with or without cognitive tasks, modifies the synaptogenesis and maturation of newborn neurons in adult rat dentate gyrus. These types of trainings have many aspects, including physical activity and exploration. Therefore, to evaluate whether physical exercise and environment exploration are able to affect synapse formation and the maturation of adult-generated neurons, GFP-retrovirus infusion was performed on rats which, on the fourth day after injection, were housed under running conditions or allowed to explore an enriched environment briefly in the absence of exercise for the following three days. Afterward, at the end of the trainings, electrophysiological and morphological studies were conducted. Considering that neurotrophic factors increase after exercise or environment exploration, hippocampal BDNF levels and TrkB receptor activation were evaluated. In this study, we show that both spontaneous physical activity and enriched environment exploration induced synaptogenesis and T-type voltage-dependent Ca(2+) currents in very immature neurons. Hippocampal BDNF levels and TrkB receptor activation were determined to be increasing following physical activity and exploration. A possible contribution of BDNF signaling in mediating the observed effects was supported by the use of 7-8-dihydroxyflavone, a selective TrkB agonist, and of ANA-12, an inhibitor of TrkB receptors

Synaptogenesis in adult-generated hippocampal granule cells is affected by behavioral experiences.

Adult-generated hippocampal immature neurons play a functional role after integration in functional circuits. Previously, we found that hippocampus-dependent learning in Morris water maze affects survival of immature neurons, even before they are synaptically contacted. Beside learning, this task heavily engages animals in physical activity in form of swimming; physical activity enhances hippocampal neurogenesis. In this article, the effects of training in Morris water maze apparatus on the synapse formation onto new neurons in hippocampus dentate gyrus and on neuronal maturation were investigated in adult rats. Newborn cells were identified using retroviral GFP-expressing virus infusion. In the first week after virus infusion, rats were trained in Morris water maze apparatus in three different conditions (spatial learning, cue test, and swimming). Properties of immature neurons and their synaptic response to perforant pathway stimulation were electrophysiologically investigated early during neuronal maturation. In controls, newborn cells showing GABAergic and glutamatergic responses were found for the first time at 8 and 10 days after mitosis, respectively; no cell with glutamatergic response only was found. Twelve days after virus infusion almost all GFP-positive cells showed both synaptic responses. The main result we found was the anticipated appearance of GABAergic synapses at 6 days in learner, cued and swimmer rats, supported also by immunohistochemical result. Swimmer rats showed the highest percentage of GFP-positive neurons with glutamatergic response at 10 and 12 days postmitosis. Moreover, primary dendrites were more numerous at 7 days in learner, cued and swimmer rats and swimmer rats showed the greatest dendritic tree complexity at 10 days. Finally, voltage-dependent Ca(2+) current was found in a larger number of newborn neurons at 7 days postinfusion in learner, cued and swimmer rats. In conclusion, experiences involving physical activity contextualized in an exploring behavior affect synaptogenesis in adult-generated cells and their early stages of maturation