Search

Vascular endothelial growth factor (VEGF) represents one of the main factors involved not only in angiogenesis and vasculogenesis but also in neuritogenesis. VEGF plays its function acting via different receptors: VEGF receptor1 (VEGFR-1), VEGF receptor2 (VEGFR-2), VEGF receptor3 (VEGFR-3), and co-receptors Neuropilin-1 (NRP1) and Neuropilin-2 (NRP2). This study reports on the first in vivo analysis of the expression of VEGF and VEGF family molecules in peripheral nerve degeneration and regeneration: for this purpose, different models of nerve lesion in rat were adopted, the median nerve crush injury and the median nerve transaction followed or not by end-to end microsurgical repair. Results obtained by real time polymerase chain reaction showed that VEGF and VEGF family molecules are differentially expressed under regenerating and degenerating condition, furthermore, in order to study the modulation and involvement of these factors in two different regenerative models, crush injury and end-to-end repair, protein expression analysis was evaluated. In addition, immunohistochemical analysis allowed to state a glial localization of VEGF and VEGFR-2 after peripheral nerve crush injury. Finally in vitro assay on primary Schwann cells culture show that VEGF165 stimulation increases Schwann cells migration, a major process in the promotion of neurite outgrowth. Anat Rec, 301:1646-1656, 2018. © 2018 Wiley Periodicals, Inc.

The evidence of neurons generatedex novoin sensory ganglia of adult animals is still debated. In the present study, we investigated, using high resolution light microscopy and stereological analysis, the changes in the number of neurons in dorsal root ganglia after 30 days from a crush lesion of the rat brachial plexus terminal branches. Results showed, as expected, a relevant hypertrophy of dorsal root ganglion neurons. In addition, we reported, for the first time in the literature, that neuronal hypertrophy was accompanied by massive neuronal hyperplasia leading to a 42% increase of the number of primary sensory neurons. Moreover, ultrastructural analyses on sensory neurons showed that there was not a relevant neuronal loss as a consequence of the nerve injury. The evidence of BrdU-immunopositive neurons and neural progenitors labeled with Ki67, nanog, nestin, and sox-2 confirmed the stereological evidence of posttraumatic neurogenesis in dorsal root ganglia. Analysis of morphological changes following axonal damage in addition to immunofluorescence characterization of cell phenotype suggested that the neuronal precursors which give rise to the newly generated neurons could be represented by satellite glial cells that actively proliferate after the lesion and are able to differentiate toward the neuronal lineage.

Inflammatory events occurring in the distal part of an injured peripheral nerve have, nowadays, a great resonance. Investigating the timing of action of the several cytokines in the important stages of Wallerian degeneration helps to understand the regenerative process and design pharmacologic intervention that promotes and expedites recovery. The complex and synergistic action of inflammatory cytokines finally promotes axonal regeneration. Cytokines can be divided into pro- and anti-inflammatory cytokines that upregulate and downregulate, respectively, the production of inflammatory mediators. While pro-inflammatory cytokines are expressed in the first phase of Wallerian degeneration and promote the recruitment of macrophages, anti-inflammatory cytokines are expressed after this recruitment and downregulate the production of all cytokines, thus determining the end of the process. In this review, we describe the major inflammatory cytokines involved in Wallerian degeneration and the early phases of nerve regeneration. In particular, we focus on interleukin-1, interleukin-2, interleukin-6, tumor necrosis factor-β, interleukin-10 and transforming growth factor-β.

The possibility that posttraumatic regeneration may eventually lead rat peripheral nerve fibers back to normal is still under debate. While it has been shown that, after a sufficiently long posttraumatic time, the number of regenerated rat peripheral nerve fibers can return to normal levels and the animal can regain normal pre-lesion function, no information regarding long-term changes in size parameters of regenerated nerve fibers is still available. To fill this gap, 24-week posttraumatic changes in myelinated axon and nerve fiber diameter, myelin thickness and g-ratio (axon diameter/fiber diameter), distal to a nerve crush (axonotmesis lesion) of the rat median nerve were assessed by stereology. Results showed that, while as expected fiber number returned to normal values at week-24, both axon and fiber diameter and myelin thickness were still significantly lower at week-24 in comparison to pre-lesion values. Finally, g-ratio, which persisted unmodified along the regeneration process, eventually resulted to be significantly reduced at week-24 in comparison to pre-lesion value. Based on these results, the hypothesis that regenerated rat peripheral nerve fibers are able to spontaneously return to normal, provided that a sufficiently long time recovery post-axonotmesis is allowed, is rejected., Italian Journal of Anatomy and Embryology, Vol 116, No 1 (Supplement) 2011

Italian Journal of Anatomy and Embryology, Vol 115, No 1/2 (Supplement) 2010

Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but signs of ataxia were detectable by beam test at 18 months. Cerebellar pathology was negative; electrophysiological analysis showed increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls, although not statistically significant. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was also altered, in line with greatly reduced expression of Opa1 fusogenic protein L-isoforms. The mitochondrial alterations observed in MEFs were also detected in cerebella of 18-month-old heterozygous mutants, suggesting they may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.

Systemic mastocytosis (SM) is a rare myeloproliferative neoplasm characterized by proliferation and hyperactivation of clonal mast cells. Clinical manifestations are heterogeneous and encompass cutaneous lesions, gastrointestinal alterations, osteoporosis, anaphylaxis and involvement of bone marrow and other organs due to neoplastic mast cells (MC) infiltration. As consequence, diagnosis may be difficult and patients (pts) are often evaluated by different specialists before the disease is recognized. To date, only few studies (Lim 2009, Escribano 2009, Cohen 2014) described relatively large series of pts with SM. We performed a multicentre retrospective study to evaluate clinical and biological features and therapeutic management in a large series of pts from 10 Italian centres experienced in management of SM and organized in multidisciplinary groups of specialists. We collected 455 pts diagnosed with SM according to WHO criteria. Additionally 26 pts with mastocytosis in the skin (MIS) evaluated with BM examination did not fulfil criteria for SM, leading to diagnosis of Cutaneous Mastocytosis (CM); however 2/26 pts with CM had both cKITD816V mutation and CD2/CD25 expression on MC in BM, additional 3 showed either cKITD816V or CD2/CD25. Moreover, we found 22 pts without MIS but with features of monoclonal mast cell activation syndrome. Of the 455 pts with WHO-SM (male 56%), 252 (55%) had MIS: median age at MIS diagnosis (dg) was 37 years (y) (range 0-79), while at SM dg it was 46.5 (range 18-82). Time from onset of MIS to dg of SM was 9 y (range 0-43). In 18/252 pts (7%) MIS occurred before age of 18 y (median 9, range 0-17) and persisted over childhood. Median age at dg of SM without MIS (203/455 pts, 45%) was older: 54 y, range 19-79 (p Disclosures Martinelli: Novartis: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Pfizer: Consultancy; ARIAD: Consultancy.