Davide Viggiano

The hyperactive syndrome: metanalysis of genetic alterations, pharmacological treatments and brain lesions which increase locomotor activity.

The large number of transgenic mice realized thus far with different purposes allows addressing new questions, such as which animals, over the entire set of transgenic animals, show a specific behavioural abnormality. In the present study, we have used a metanalytical approach to organize a database of genetic modifications, brain lesions and pharmacological interventions that increase locomotor activity in animal models. To further understand the resulting data set, we have organized a second database of the alterations (genetic, pharmacological or brain lesions) that reduce locomotor activity. Using this approach, we estimated that 1.56% of the genes in the genome yield to hyperactivity and 0.75% of genes produce hypoactivity when altered. These genes have been classified into genes for neurotransmitter systems, hormonal, metabolic systems, ion channels, structural proteins, transcription factors, second messengers and growth factors. Finally, two additional classes included animals with neurodegeneration and inner ear abnormalities. The analysis of the database revealed several unexpected findings. First, the genes that, when mutated, induce hyperactive behaviour do not pertain to a single neurotransmitter system. In fact, alterations in most neurotransmitter systems can give rise to a hyperactive phenotype. In contrast, fewer changes can decrease locomotor activity. Specifically, genetic and pharmacological alterations that enhance the dopamine, orexin, histamine, cannabinoids systems or that antagonize the cholinergic system induce an increase in locomotor activity. Similarly, imbalances in the two main neurotransmitters of the nervous system, GABA and glutamate usually result in hyperactive behaviour. It is remarkable that no genetic alterations pertaining to the GABA system have been reported to reduce locomotor behaviour. Other neurotransmitters, such as norepinephrine and serotonin, have a more complex influence. For instance, a decrease in norepinephrine synthesis usually results in hypoactive behaviour. However, a chronic increase in norepinephrine may result in hypoactivity too. Similarly, changes in both directions of serotonin levels may reduce locomotor activity, whereas alterations in specific serotonin receptors can induce hyperactivity. The lesion of at least 12 different brain regions can increase locomotor activity too. Comparatively, few focal lesions decrease locomotor activity. Finally, a large number of toxic events can increase locomotor activity, particularly if delivered during the prepuberal time window. These data show that there is a net imbalance in the number of altered genes/brain lesions/toxics that induce hyperactivity versus hypoactive behaviour. Although some of these data may be explained in terms of the activating role of subcortical systems (such as catecholamines), the larger number of alterations that induce hyperactivity suggests a different scenario. Specifically, we hypothesize (i) the existence of a control system that continuously inhibit a basally hyperactive locomotor tone and (ii) that this control system is highly vulnerable (intrinsic fragility) to any change in the genetic asset or to any toxic/drug delivered during prepuberal stages. Brain lesion studies suggest that the putative control system is located along an axis that connects the olfactory bulb and the enthorhinal cortex (enthorhinal-hippocampal-septal-prefrontal cortex-olfactory bulb axis). We suggest that the increased locomotor activity in many psychiatric diseases may derive from the interference with the development of this brain axis during a specific postnatal time window.

Pre-synaptic BK channels selectively control glutamate versus GABA release from cortical and hippocampal nerve terminals

J. Neurochem. (2010) 115, 411–422.

Minor varus alignment provides better results than neutral alignment in medial UKA.

INTRODUCTION Few data exist regarding the outcome and survivorship of medial UKA in patients with minor varus alignment. The purpose of this study was therefore to analyse the clinical results of medial UKA implanted with no more than 7° of varus, and to verify whether there was a relationship between limb alignment and overall outcomes. MATERIAL AND METHODS One hundred and twenty five medial fixed-bearing UKAs with no more than 7° of varus were retrospectively analysed. The varus/valgus inclination and thickness of the bone cuts were performed relating to the proximal tibial epiphyseal axis. Patients were assessed with the IKS scores and range of knee motion. The subjects were classified into three groups according to the postoperative femoro-tibial mechanical alignment angle (group A: -2° to 1°; group B: 2° to 4°; group C: 5° to 7°). RESULTS The mean follow-up was 7.6years (range, 3.5-9.3). IKS knee scores increased proportionally with increasing varus according to a linear relationship (p≪0.01). Additionally, IKS knee scores were significantly higher in group B and still higher in group C if compared to those in group A (p=0.003). Finally, a significantly higher frequency of IKS function scores>90 points in subjects with femoro-tibial mechanical alignment angle≥4° was found (p=0.009). CONCLUSIONS Minor varus alignment does not compromise the mid- to long-term outcome of a medial UKA, and gives better results compared to neutral or close-to-neutral alignment. LEVEL OF EVIDENCE IV - Retrospective case series study.

PED/PEA-15 induces autophagy and mediates TGF-beta1 effect on muscle cell differentiation

TGF-beta1 has been shown to induce autophagy in certain cells but whether and how this action is exerted in muscle and whether this activity relates to TGF-beta1 control of muscle cell differentiation remains unknown. Here, we show that expression of the autophagy-promoting protein phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes (PED/PEA-15) progressively declines during L6 and C2C12 skeletal muscle cell differentiation. PED/PEA-15 underwent rapid induction upon TGF-beta1 exposure of L6 and C2C12 myoblasts, accompanied by impaired differentiation into mature myotubes. TGF-beta1 also induced autophagy in the L6 and C2C12 cells through a PP2A/FoxO1-mediated mechanism. Both the TGF-beta1 effect on differentiation and that on autophagy were blocked by specific PED/PEA-15 ShRNAs. Myoblasts stably overexpressing PED/PEA-15 did not differentiate and showed markedly enhanced autophagy. In these same cells, the autophagy inhibitor 3-methyladenine rescued TGF-beta1 effect on both autophagy and myogenesis, indicating that PED/PEA-15 mediates TGF-beta1 effects in muscle. Muscles from transgenic mice overexpressing PED/PEA-15 featured a significant number of atrophic fibers, accompanied by increased light chain 3 (LC3)II to LC3I ratio and reduced PP2A/FoxO1 phosphorylation. Interestingly, these mice showed significantly impaired locomotor activity compared with their non-transgenic littermates. TGF-beta1 causes transcriptional upregulation of the autophagy-promoting gene PED/PEA-15, which in turn is capable to induce atrophic responses in skeletal muscle in vivo.

Restoration of foveal thickness and architecture after macula-off retinal detachment repair.

PURPOSE To investigate the foveal changes after repair of macula-off rhegmatogenous retinal detachment (RRD). METHODS Prospective comparative case series. Twenty-four eyes of 24 patients with macula-off/fovea-on detachment (n = 9) and fovea-off detachment (n = 15) were studied. Serial optical coherence tomography (OCT) images taken at the same location were recorded at months 1, 3, 6, and 12 after operation. Fellow eyes were used as controls. RESULTS No significant changes of the central foveal thickness (CFT) were recorded in the fovea-on group over the follow-up. From month 1 to month 12, CFT increased significantly in the fovea-off group (P < 0.00001). In this group, a significant increase of the Henle fiber and outer nuclear layer (HFL + ONL, P = 0.007), external limiting membrane (ELM)-ellipsoid zone (EZ; P = 0.03), and EZ-retinal pigment epithelium (RPE) thicknesses (P < 0.00001) was recorded. Significant restoration of the integrity of the ELM in the fovea-off group (P < 0.001) and of the EZ and cone interdigitation zone in the fovea-on group and the fovea-off group was observed (P = 0.02 and P < 0.001, and P = 0.002 and P < 0.001, respectively). Twelve months after operation the foveal bulge restored in 8 of 15 eyes of the fovea-off group. Multiple regression analysis showed that in the fovea-off group BCVA correlated with EZ-RPE thickness at months 1 and 12, whereas the improvement of BCVA during the 12 months follow-up correlated with the increase of ELM-RPE thickness. CONCLUSIONS Optical coherence tomography scans taken serially at the same location showed a progressive increase of HNL+ONL, ELM-EZ, and EZ-RPE thicknesses and restoration of the integrity of outer retinal bands after repair of fovea-off RRD. The use of software able to rescan at exactly the same area is crucial to correctly follow and interpret the reconstitution of the retinal bands and to correlate them to BCVA recovery.

Brain distribution of genes related to changes in locomotor activity

The relationship between genes and behavior, and particularly the hyperactive behavior, is clearly not linear nor monotonic. To address this problem, a database of the locomotor behavior obtained from thousands of mutant mice has been previously retrieved from the literature. Data showed that the percent of genes in the genome related to locomotor hyperactivity is probably more than 1.56%. These genes do not belong to a single neurotransmitter system or biochemical pathway. Indeed, they are probably required for the correct development of a specific neuronal network necessary to decrease locomotor activity. The present paper analyzes the brain expression pattern of the genes whose deletion is accompanied by changes in locomotor behavior. Using literature data concerning knockout mice, 46 genes whose deletion was accompanied by increased locomotor behavior, 24 genes related to decreased locomotor behavior and 23 genes not involved in locomotor behavior (but important for other brain functions) have been identified. These three groups of genes belonged to overlapping neurotransmitter systems or cellular functions. Therefore, we postulated that a better predictor of the locomotor behavior resulting from gene deletion might be the brain expression pattern. To this aim we correlated the brain expression of the genes and the locomotor activity resulting from the deletion of the same genes, using two databases (Allen Brain Atlas and SymAtlas). The results showed that the deletion of genes with higher expression level in the brain had higher probability to be accompanied by increased behavioral activity. Moreover the genes that were accompanied by locomotor hyperactivity when deleted, were more expressed in the cerebral cortex, amygdala and hippocampus compared to the genes unrelated to locomotor activity. Therefore, the prediction of the behavioral effect of a gene should take into consideration its brain distribution. Moreover, data confirmed that genes highly expressed in the brain are more likely to induce hyperactivity when deleted. Finally, it is suggested that gene mutations linked to specific behavioral abnormalities (e.g. inattention) might probably be associated to hyperactivity if the same gene has elevated brain expression.

Delay in Renal Hemodynamic Response to a Meat Meal in Severe Obesity

Background/Aims: Little information is available about the tubular functions and the renal adjustments that take place in obese subjects after a protein meal. How the excess fat may affect renal response to dietary proteins is currently only partially understood. This paper aims to address (i) whether severe obesity, in the absence of other comorbidities, is responsible of kidney dysfunction at either the glomerular or the tubular level and (ii) whether it compromises renal adaptations to a large protein meal. Methods: Twenty-eight obese subjects without albuminuria, along with 20 control subjects, age and gender matched, have been studied. The glomerular filtration rate (GFR; inulin clearance), renal plasma flow (p-aminohippurate clearance), the proximal tubular function (lithium clearance), the fractional excretion of sodium (FPRNa) have been measured at the basal level (steady state) and after a protein meal (perturbation). Results: Under steady state conditions, filtration fraction, proximal tubular sodium handling and the FPRNa were not significantly different in non proteinuric obese subjects compared with controls. However, a protein meal led to a delayed glomerular hyperfiltration in obese patients compared with controls. Conclusion: This study shows that obese patients, in the absence of significant comorbidities, have a normal proximal tubule Na+ absorption at basal; conversely, these subjects showed a different response to a protein meal compared with normal subjects in terms of changes of GFR. Overall, these results suggest that the modified hemodynamic response to a protein meal might be the earliest hallmark of future kidney dysfunction in obese subjects.

Parkinson-like phenotype in insulin-resistant PED/PEA-15 transgenic mice

Neurological abnormalities, such as Parkinson-like disorders (PlD), are often co-morbidities of Type 2 Diabetic (T2D) patients, although the epidemiological link between these two disorders remains controversial. The PED/PEA-15 protein represents a possible candidate linking T2D and PD, because it is increased in subjects with T2D and is highly expressed in the brain. To test this hypothesis, we have analyzed the neurological and neurochemical phenotype of transgenic mice overexpressing PED/PEA-15 (tgPED). These mice develop impaired glucose tolerance and insulin resistance, accompanied by neurological features resembling PlD: feet clasping, slow and delayed locomotor movements in different behavioral tests in absence of clear cognitive deficits, ataxia or anxiety. Morphological analysis of the brains showed selective modifications of metabolic activity in the striatal region. In the same region, we have observed 26% decrease of dopamine fibers, confirmed by immunohistochemistry and Western Blot for tyrosine hydroxylase. Moreover, they also showed 48% reduction of dopamine levels in the striatum. Thus the tgPED mice may represent a genetic animal model of neurological disease linked to T2D.

The kinematic control during the backward gait and knee proprioception: Insights from lesions of the anterior cruciate ligament

Abstract An already existing large volume of work on kinematics documents a reduction of step length during unusual gaits, such as backward walking. This is mainly explained in terms of modifications of some biomechanical properties. In the present study, we propose that the proprioceptive information from the knee may be involved in this change of motor strategy. Specifically, we show that a non-automated condition such as backward walking can elicit different motor strategies in subjects with reduced proprioceptive feedback after anterior cruciate ligament lesion (ACL). For this purpose, the kinematic parameters during forward and backward walking in subjects with ACL deficit were compared to two control groups: a group with intact ACL and a group with surgically reconstructed ACL. The knee proprioception was tested measuring the threshold for detection of passive knee motion. Subjects were asked to walk on a level treadmill at five different velocities (1-5km/h) in forward and backward direction, thereby calculating the cadence and step length. Results showed that forward walking parameters were largely unaffected in subjects with ACL damage. However, they failed to reduce step length during backward walking, a correction that was normally observed in all control subjects and in subjects with normal proprioceptive feedback after ACL reconstruction. The main result of the present study is that knee proprioception is an important signal used by the brain to reduce step length during the backward gait. This can have a significant impact on clinical evaluation and rehabilitation.

Cell viability studies and operation in cellular culture medium of n-type organic field-effect transistors

The possibility of the fabrication of organic devices suitable to be applied in bio-sensing fields depends largely on the availability of organic compounds displaying robust electrical properties even in aqueous solutions and effective biocompatibility features. In this paper, we report about the good cellular biocompatibility and the electrical response stability in an ionic medium of n-type organic transistors based on the recently developed PDI-8CN2 oligomer. The biocompatibility has been tested by analyzing the adhesion and viability of two different cell lines, human epithelial HeLa cells and murine neuronal F11 cells, on PDI-8CN2 films grown by organic molecular beam deposition (OMBD) on SiO2 substrates. The effect of film thickness on cell attachment was also tested. Uncoated SiO2 substrates were used as control surfaces and sexithiophene (T6) as device testing control. Moreover, the possible toxicity of –CN groups of PDI-8CN2 was tested on HeLa cell cultures, using PDI-8 and T6 molecules as contro...