Diego Garbossa

Human mesenchymal stem cell transplantation extends survival, improves motor performance and decreases neuroinflammation in mouse model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a lethal disease affecting motoneurons. In familial ALS, patients bear mutations in the superoxide dismutase gene (SOD1). We transplanted human bone marrow mesenchymal stem cells (hMSCs) into the lumbar spinal cord of asymptomatic SOD1(G93A) mice, an experimental model of ALS. hMSCs were found in the spinal cord 10 weeks after, sometimes close to motoneurons and were rarely GFAP- or MAP2-positive. In females, where progression is slower than in males, astrogliosis and microglial activation were reduced and motoneuron counts with the optical fractionator were higher following transplantation. Motor tests (Rotarod, Paw Grip Endurance, neurological examination) were significantly improved in transplanted males. Therefore hMSCs are a good candidate for ALS cell therapy: they can survive and migrate after transplantation in the lumbar spinal cord, where they prevent astrogliosis and microglial activation and delay ALS-related decrease in the number of motoneurons, thus resulting in amelioration of the motor performance.

Recent techniques for tracing pathways in the central nervous system of developing and adult mammals

Over the last 20 years, the choice of neural tracers has increased manyfold, and includes newly introduced anterograde tracers that allow quantitation of single-axon morphologies, and retrograde tracers that can be combined with intracellular fills for the study of dendritic arbors of neurons which have a specific projection pattern. The combination of several different tracers now permits the comparison of multiple connections in the same animal, both quantitatively and qualitatively. Moreover, the finding of new virus strains, which infect neural cells without killing them, provides a tool for studying multisynaptic connections that participate in a circuit. In this paper, the labeling characteristics, mechanism of transport and advantages/disadvantages of use are discussed for the following recently introduced neural tracers: carbocyanine dyes, fluorescent latex microspheres, fluorescent dextrans, biocytin, dextran amines, Phaseolus vulgaris leucoagglutinin, cholera toxin and viruses. We also suggest the choice of specific tracers, depending on the experimental animal, age and type of connection to be studied, and discuss quantitative methodologies.

Neuropsychological assessment after microsurgical clipping or endovascular treatment for anterior communicating artery aneurysm

Summary¶Background. After open surgery for ruptured ACoA aneurysms, several patients who have achieved a favourable neurological outcome still exhibit significant cognitive deficits. The aim of this study was to investigate the cognitive performances in patients with ACoA aneurysms submitted to different therapeutic options such as endovascular treatment and surgical clipping. Methods. We evaluated 37 consecutive patients in WFNS grade I or II, who underwent an early treatment (within 48 hours) of a bleeding ACoA aneurysm: 20 out of 37 were surgically clipped (group A) and 17 were treated with endovascular coiling (group B).These two groups were compared with 16 patients (group C) with subarachnoid haemorrhage and negative cerebral panangiography and with 18 volunteers (group D) without neurological or psychiatric disorders.All patients were neurologically intact at discharge and were in Glasgow Outcome Scale 1 at 6 months follow-up after SAH.All subjects were tested to assess selective attention, verbal, spatial and logical memory, frontal lobe executive functions, language and intelligence. Depressive symptoms and anxiety were also examined. Findings. Selective attention, verbal and spatial memory, and intelligence tests didn’t show any significant difference between the patients and the controls.Surgically treated patients showed a significant worse performance on the logical memory and on the frontal lobe executive functions compared to controls, while the endovascular group and the group C (not treated) showed a significant decrease only in the literal fluency score.Moreover, the surgical group showed a significant impairment in using grammatical and syntactical rules to produce sentences. No significant difference was found between the group B, C and controls. Treated patients were not significantly more depressive or anxious than controls. Interpretation. Investigation of neuropsychological deficits can show an impairment, even in patients classified as good outcome by Glasgow Outcome Scale (GOS).The frontal lobe functions and language are impaired especially in surgically treated in comparison with controls, but no significant difference was found respect to the endovascular and no treated patients (group C).

NOS inhibition during postnatal development leads to increased ipsilateral retinocollicular and retinogeniculate projections in rats

Synthesis of nitric oxide (NO) occurs downstream from activation of N‐methyl‐ d‐aspartate (NMDA) receptors; NO reportedly acts as a retrograde messenger, influencing the refinement and stabilization of coactive afferent terminals. Cells and neuropil in the rat superior colliculus (SC) and lateral geniculate body (LGB) show intense, developmentally regulated activity for NO synthase (NOS). To study the role of NO in the development of retinogeniculate and retinotectal axon arbors, we examined primary visual projections of rats that had received intraperitoneal injections of Nω‐nitro‐l‐arginine (L‐NoArg, an NOS inhibitor) on postnatal day 0, and daily thereafter for 4–6 weeks. Treated rats showed significant alterations in ipsilateral retinotectal projections, in the mediolateral and anteroposterior axes; there was an increase in the density of fibres entering the SC, in branch length, and in the numbers of boutons on retinotectal arbors in the treated group. Ipsilaterally projecting retinal axons also showed an increase in density and distribution in the dorsal nucleus of the LGB. If animals were allowed to survive for several months after stopping treatment, similar changes were also noted, but these were much less striking. Our results support the hypothesis that, in the mammalian visual system, NO released from target neurons in the SC and LGB serves as a retrograde signal which feeds back on retinal afferents, influencing their growth. The effects of NOS inhibition are partially reversed after treatment is stopped, indicating that lack of NO synthesis delays the maturation of retinofugal connections, and also that NO plays a constitutive role in their development.

Recent therapeutic strategies for spinal cord injury treatment: possible role of stem cells

Spinal cord injury (SCI) often results in significant dysfunction and disability. A series of treatments have been proposed to prevent and overcome the formation of the glial scar and inhibitory factors to axon regrowth. In the last decade, cell therapy has emerged as a new tool for several diseases of the nervous system. Stem cells act as minipumps providing trophic and immunomodulatory factors to enhance axonal growth, to modulate the environment, and to reduce neuroinflammation. This capability can be boosted by genetical manipulation to deliver trophic molecules. Different types of stem cells have been tested, according to their properties and the therapeutic aims. They differ from each other for origin, developmental stage, stage of differentiation, and fate lineage. Related to this, stem cells differentiating into neurons could be used for cell replacement, even though the feasibility that stem cells after transplantation in the adult lesioned spinal cord can differentiate into neurons, integrate within neural circuits, and emit axons reaching the muscle is quite remote. The timing of cell therapy has been variable, and may be summarized in the acute and chronic phases of disease, when stem cells interact with a completely different environment. Even though further experimental studies are needed to elucidate the mechanisms of action, the therapeutic, and the side effects of cell therapy, several clinical protocols have been tested or are under trial. Here, we report the state-of-the-art of cell therapy in SCI, in terms of feasibility, outcome, and side effects.

Fluorescence and image guided resection in high grade glioma

The extent of resection in high grade glioma is increasingly been shown to positively effect survival. Nevertheless, heterogeneity and migratory behavior of glioma cells make gross total resection very challenging. Several techniques were used in order to improve the detection of residual tumor. Aim of this study was to analyze advantages and limitations of fluorescence and image guided resection. A multicentric prospective study was designed to evaluate the accuracy of each method. Furthermore, the role of 5-aminolevulinc acid and neuronavigation were reviewed. Twenty-three patients harboring suspected high grade glioma, amenable to complete resection, were enrolled. Fluorescence and image guides were used to perform surgery. Multiple samples were obtained from the resection cavity of each lesion according to 5-ALA staining positivity and boundaries as delineated by neuronavigation. All samples were analyzed by a pathologist blinded to the intra-operative labeling. Decision-making based on fluorescence showed a sensitivity of 91.1% and a specificity of 89.4% (p<0.001). On the other hand, the image-guided resection accuracy was low (sensitivity: 57.8%; specificity: 57.4%; p=0.346). We observed that the sensitivity of 5-ALA can be improved by the combined use of neuronavigation, but this leads to a significant reduction in specificity. Thus, the use of auxiliary techniques should always be subject to critical skills of the surgeon. We advocate a large-scale study to further improve the assessment of multimodal approaches.

Mesenchymal Stem Cell Transplantation Reduces Glial Cyst and Improves Functional Outcome After Spinal Cord Compression

BACKGROUND Mesenchymal stem cells (MSCs) are multipotent stem cells that have a supportive role in regenerative therapies, especially in the central nervous system, where spontaneous regeneration is limited. MSCs can exert a paracrine activity and modulate the inflammatory response after a central nervous system injury. Spinal cord injury (SCI) leads to permanent neurologic deficits below the injury site, owing to neuronal and axonal damage. Among experimental treatments after SCI, cell transplantation has emerged as a promising approach. METHODS Using a compression injury model in the mouse spinal cord, MSCs were acutely transplanted into the lesion cavity; injured mice without the graft served as controls. After 26 days, the survival of MSCs was investigated, and their effect on the formation of glial cyst and on injury-related inflammation was evaluated. RESULTS Grafted MSCs remained permanently undifferentiated. The lesion volume was reduced by 31.6% compared with control mice despite the fact that astroglial and microglial activation was not altered by the graft. Sensory and motor tests showed that MSC cell therapy results in improvement on a battery of behavioral tests compared with control mice: MSC-treated mice versus control mice scored 0.00 versus 0.50 in the posture test, 0.00 versus 1.50 in the hindlimb flexion test, 3.00 versus 2.25 in the sensory test, and 7.50 mistakes versus 15.83 mistakes in the foot-fault test. CONCLUSIONS These results underscore the therapeutic potential of MSCs, making them promising treatments for central nervous system pathologies.

Embryonic and adult stem cells promote raphespinal axon outgrowth and improve functional outcome following spinal hemisection in mice

Spinal cord injury (SCI) often results in permanent neurological deficits below the injury site. Serotonergic raphespinal projections promote functional recovery after SCI, but spontaneous regeneration of most severed axons is limited by the glial cyst and scar that form at the lesion site. Stem cell (SC) transplantation offers a promising approach for inducing regeneration through the damaged area. Here we compare the effects of transplantation of embryonic neural precursors (NPs) or adult mesenchymal SCs, both of which are potential candidates for SC therapy. The spinal cord was hemisected at the L2 neuromer in adult mice. Two weeks post‐injury, we transplanted neural precursors or mesenchymal SCs into the cord, caudal to the hemisection. Injured mice without a graft served as controls. Mice were tested for functional recovery on a battery of motor tasks, then killed and analysed for survival of grafted cells, for effects of engraftment on the local cellular environment and for the sprouting of serotonergic axons. Both types of SCs survived and were integrated into the host tissue, but only the NPs expressed neuronal markers. All transplanted animals displayed an increased number of serotonin‐positive fibres caudal to the hemisection, compared with untreated mice. And both cell types led to improved motor performance. These results point to a therapeutic potential for such cell grafting.

TUMOR NECROSIS FACTOR-α GENE AND CEREBRAL ANEURYSMS

OBJECTIVEThe pathogenesis of intracranial aneurysms is still uncertain. In addition to atherosclerosis, immunological factors may play a role in the disease. Recent studies have suggested that tumor necrosis factor-α (TNF-α), one of the main proinflammatory cytokines, may play a key role in the formation and rupture of cerebral aneurysms. The purpose of this study is to evaluate the association of a functionally active polymorphism (−308 G<A) in the TNF-α gene with the risk and the clinical features of aneurysmal subarachnoid hemorrhage. METHODSA total of 171 consecutive aneurysmal subarachnoid hemorrhage patients and 144 healthy controls were involved in the study. Computed tomographic scan findings were assessed by Fisher grade; clinical neurological assessment was performed using the Hunt and Hess grading system. Patients and controls were genotyped for the−308 biallelic (G<A) polymorphism of the TNF-α gene. RESULTSThe TNF-α G allele was significantly more frequent in patients than in controls (χ2 = 5.59; P = 0.0181) and homozygosity for the G allele, compared with remaining genotypes, was associated with a significantly increased risk of aneurysmal subarachnoid hemorrhage (odds ratio = 2.20; 95% confidence interval = 1.29<odds ratio<3.75). Allelic and genotypic frequencies of the examined polymorphism were not significantly different in disease subgroups. The different TNF-α genotypes do not seem to significantly modify the main clinical features of the disease. CONCLUSIONOur data suggests that the TNF-α gene or a linked locus significantly modulates the risk for aneurysmal subarachnoid hemorrhage. Additional studies in different populations are warranted to confirm our findings.

New strategies for repairing the injured spinal cord: the role of stem cells

Abstract Thanks to advances in the stem cell biology of the central nervous system, the previously unconceivable regeneration of the damaged spinal cord is approaching reality. A number of potential strategies aim to optimize functional recovery after spinal cord injury. They include minimizing the progression of secondary injury, manipulating the inhibitory environment of the spinal cord, replacing lost tissue with transplanted cells or peripheral nerve grafts, remyelinating denuded axons and maximizing the intrinsic regenerative potential of endogenous progenitor cells. We review the application of stem cell transplantation to the spinal cord, emphasizing the use of embryonic stem cells for remyelinating damaged axons. Recent advancements in neural injury and repair, and the progress towards development of neuroprotective and regenerative interventions are discussed.