Bruno Bonetti | Academy of Economic Studies from Moldova (original) (raw)

Papers by Bruno Bonetti

Acta Neuropathologica, 1995

We report the results of a clinical, electrophysiological and pathological study conducted in 18 ... more We report the results of a clinical, electrophysiological and pathological study conducted in 18 AIDS patients presenting a distal symmetrical predominantly sensory polyneuropathy (DSPN) characterized by painful dysesthesias as main complaint. Onset of the neuropathy was at CDC (Center for Disease Control) stage II in 2 patients, at CDC stage III in 5 patients and at CDC stage IV in the remainder. Electrophysiological investigation confirmed the presence of an axonal alteration in the sensory nerves, but also revealed motor involvement in all cases. The neuropathological features of sensory nerves were fiber loss and axonal degeneration with macrophagic activation. The expression of monocyte-macrophage markers and of major histocompatibility complex class II antigens appeared up-regulated in endoneurial ramified cells, while expression of CR3, a complement receptor involved in the process of phagocytosis, was down-regulated. In six nerve biopsy samples and in two out of five DSPN dorsal root ganglia we found HIV-related mRNA and protein located in scattered cells of the endoneurium which we presume to be macrophages. These data suggest that: (a) DSPN may occur early in the course of the disease and is not limited to later stages; (b) DSPN is not a ganglionitis but is actually a sensory-motor neuropathy; (c) the virus enters the peripheral nervous system and induces changes in the immunocompetent cell population with activation of macrophages. Storage of the virus inside macrophages may act both as a reservoir for the virus and as a putative cause of nerve damage, probably through release of cytotoxins and/or interaction with trophic factors.

Stem Cells and Development, 2008

Adult mesenchymal stem cells derived from adipose tissue (A-MSC) have the capacity to differentia... more Adult mesenchymal stem cells derived from adipose tissue (A-MSC) have the capacity to differentiate in vitro into mesenchymal as well as endodermal and ectodermal cell lineages. We investigated the neuronal differentiation potential of human A-MSC with a protocol which included sphere formation and sequential culture in brain-derived neurotrophic factor (BDNF) and retinoic acid (RA). After 30 days, about 57% A-MSC showed morphological, immunocytochemical and electrophysiological evidence of initial neuronal differentiation. In fact, A-MSC displayed elongated shape with protrusion of two or three cellular processes, selectively expressed nestin and neuronal molecules (including GABA receptor and tyroxine hydroxilase) in the absence of glial phenotypic markers. Differentiated cells showed negative membrane potential (-60 mV), delayed rectifier potassium currents and TTX-sensitive sodium currents. Such changes were stable for at least 7 days after removal of differentiation medium. In view of these results and the easy availability of adipose tissue, A-MSC may be a ready source of adult MSC with neuronal differentiation potential, an useful tool to treat neurodegenerative diseases.

Annals of Neurology, 1997

To investigate whether apoptosis is involved in the fate of oligodendrocytes in chronic multiple ... more To investigate whether apoptosis is involved in the fate of oligodendrocytes in chronic multiple sclerosis lesions, the pro-apoptotic molecules fas and tumor necrosis factor receptors and the anti-apoptotic molecule bcl-2 were examined by immunohistochemistry, and DNA fragmentation was assessed by an end labeling technique. Fas and both tumor necrosis factor receptors were preferentially expressed on oligodendrocytes in multiple sclerosis lesions, this phenotype being more evident at the lesion edge. The ligand for fasL, was constitutively present at high levels on microglia. The anti-apoptotic molecule bcl-2 was selectively expressed on oligodendrocytes in silent lesions and on astrocytes in active lesions. These molecules were also detected in control material, albeit at lower levels. In chronic active lesions, a few inflammatory cells displayed fas reactivity, whereas the majority expressed bcl-2. DNA fragmentation was found in a number of infiltrating cells and some microglia, whereas, with one possible exception, oligodendrocytes showed no evidence of apoptosis. Thus, while apoptosis is involved in the elimination of infiltrating cells, it plays little or no role in oligodendrocyte depletion in multiple sclerosis, a process that may be related to a lytic pathway. In addition, microglia constitutively displayed the ligand for fas, and appeared to be the major effector cell population in the central nervous system.

Journal of Neuroimmunology, 2000

In this report we review current information on the phenotypic and functional properties of γδ T ... more In this report we review current information on the phenotypic and functional properties of γδ T cells in demyelinating disorders. The results support the conclusion that although γδ T cells show evidence of activation in patients with either multiple sclerosis (MS) or Guillain Barrè syndrome (GBS), differences exist in the phenotypic and functional properties of these cells between the two

Neuromuscular Disorders, 2003

Annals of Neurology, 1994

We studied the frequency and clinical correlates of different IgM specificities in 75 patients wi... more We studied the frequency and clinical correlates of different IgM specificities in 75 patients with neuropathy associated with IgM monoclonal gammopathy. Patients were tested for IgM reactivity with the myelin-associated glycoprotein, PO, neurofilaments, and tubulin by immunoblot; with GM1, asialo-GM1, GM2, GD1a, GD1b, sulfatide, and chondroitin sulfate C by enzyme-linked immunosorbent assay; and with brain and nerve glycolipids by overlay highperformance thin-layer chromatography. Forty-two patients (56%) had high titers of IgM antibodies to MAG; 4 (5%), to sulfatide (1 also to myelin-associated glycoprotein); 4 (5%), to the 200-kd neurofilament (2 also to myelin-associated protein); and 1 each, to GD1b and chondroitin sulfate C. No reactivity was found in 26 patients (35%). More patients with anti–myelin-associated glycoprotein IgM (62%) than with unknown IgM reactivity (31%) had a predominantly sensory neuropathy (p < 0.025). Nerve conduction findings were consistent with a demyelinating neuropathy in 77% of patients reactive to myelin-associated glycoprotein and 24% with unknown reactivity (p < 0.0001) and the mean conduction velocity of peroneal nerve was lower in the former group (22.9 m/sec) than in the latter group (39.6 m/sec) (p < 0.000001). Patients with anti–sulfatide IgM had a sensorimotor neuropathy with morphological evidence of demyelination while anti–neurofilament IgM was not associated with homogeneous findings. Patients with anti–GD1b or anti–chondroitin sulfate C IgM had a predominantly motor impairment. The frequent occurrence of anti–neural IgM antibodies in neuropathy associated with IgM gammopathy, and their frequent, though not constant association with similar neuropathy features, support their possible pathogenetic role in the neuropathy.

Bone, 2007

Mesenchymal stem cells (MSCs) from bone marrow (BM) and sub-cutaneous fat are known to differenti... more Mesenchymal stem cells (MSCs) from bone marrow (BM) and sub-cutaneous fat are known to differentiate into neural cells under appropriate stimuli. We describe here the neural-like differentiation of human MSCs obtained from spleen and thymus, induced either with chemical factors or with co-culture with human Schwann cells (Sc). Under the effect of neural differentiation medium, most MSCs from BM, fat, spleen and thymus acquired morphological changes suggestive of cells of astrocytic/neuronal and oligodendroglial lineages with general up-regulation of neural molecules not correlated with morphological changes. The process was transient and reversible, as MSCs recovered basal morphology and phenotype, as well as their multilineage differentiation potential. Thus, we hypothesized that chemical factors may prime MSCs for neural differentiation, by inducing initial and poorly specific changes. By contrast, co-cultures of MSCs of different origin with Sc induced long-lasting and Sc differentiation, i.e., the expression of Sc myelin proteins for up to 12 days. Our results show that a MSC reservoir is present in tissues other than BM and fat, and that MSCs of different origin have similar neural differentiation potential. This evidence provides new insights into BM-like tissue plasticity and may have important implications for future therapeutic interventions in chronic neuropathies.

Stem Cells and Development, 2007

We show here that human and mouse mesenchymal stem cells (MSCs) can be obtained not only from bon... more We show here that human and mouse mesenchymal stem cells (MSCs) can be obtained not only from bone marrow (BM), but also from adult spleen and thymus. In vitro, both human and mouse spleen- and thymus-derived MSCs exhibit immunophenotypic characteristics and differentiation potential completely comparable to BM-MSCs. In addition, they can inhibit immune responses mediated by activated T lymphocytes with efficiency comparable to BM-MSCs. In vivo, mouse MSCs from BM, spleen, and thymus, if injected together with a genetically modified tumor cell vaccine, can equally prevent the onset of an anti-tumor memory immune response, thus leading to tumor growth in normally resistant mice. Our data suggest that not only do spleen and thymus have a stem cell reservoir to build up their stromal architecture, but also contain microenviromental immunoregulatory cells with the same properties of BM-MSCs.

Journal of Neuroimmunology, 2005

Few studies have assessed the glycolipid phenotype of glial cells in the human central nervous sy... more Few studies have assessed the glycolipid phenotype of glial cells in the human central nervous system (CNS) in situ. We investigated by immunohistochemistry the expression and cellular distribution of a panel of gangliosides (GM1, GM2, acetyl-GM3, GD1a, GD1b, GD2, GD3, GT1b, GQ1b and the A2B5 antibody) in adult, human normal and pathological brain, namely multiple sclerosis (MS) and other neurological diseases (OND). In normal conditions, we found diffuse expression in the white matter of most gangliosides tested, with the exception of acetyl-GM3, GT1b and GQ1b. By double immunofluorescence with phenotypic markers, GM1 and GD1b were preferentially expressed on GFAP+ astrocytes, GD1a on NG2+ oligodendrocyte precursors, A2B5 immunostained both populations, while GD2 was selectively present on mature oligodendrocytes. In the gray matter, only GM1, GD2 and A2B5 were present on neuronal cells. Interestingly, those gangliosides present on astrocytes in normal conditions were preferentially expressed on NG2+ cells in chronic MS lesions and in OND. Selective expression of GT1b upon astrocytes and NG2+ cells was instead observed in MS lesions, but not in OND. The definition of the glycolipid phenotype of CNS glial cells may be useful to identify distinct biological glial subsets and provide insights on the potential autoantigenic role of gangliosides in CNS autoimmune diseases.

Italian Journal of Neurological Sciences, 1991

Neurological complications of Coxiella burnetii infection (Q fever) are rare, although the occurr... more Neurological complications of Coxiella burnetii infection (Q fever) are rare, although the occurrence of headache, paresthesias, and transient focal deficits has been reported. We report the case of a patient with a relapsing demyelinating polyradiculoneuritis as an aftermath of C. burnetii endocarditis and pneumonia. Le complicanze neurologiche in corso di infezione da Coxiella burnetii (febbre Q) sono rare, sebbene siano state frequentemente segnalate cefalea, parestesie e deficit focali transitori. Viene riportato il caso diun paziente con una poliradicolonervite demielinizzante ricorrente quale conseguenza di un 'infezione polmonare e cardiaca causata dalla C. burnetii.

Journal of Neuropathology and Experimental Neurology, 1995

We investigated the role of anti-myelin-associated glycoprotein (MAG) IgM and complement (C) in t... more We investigated the role of anti-myelin-associated glycoprotein (MAG) IgM and complement (C) in the pathogenesis of myelin alterations occurring in patients with anti-MAG-associated polyneuropathy. For this purpose, we separately studied the effects of anti-MAG antibodies and terminal C complex (TCC) after injection into the rabbit sciatic nerve. The two different local treatments produced identical ultrastructural abnormalities such as intramyelinic edema, myelin vesiculation and, in particular, separation of the major dense lines with the formation of widely spaced myelin, a peculiar feature encountered in human peripheral nerve disorders with circulating anti-myelin monoclonal IgM. In nerves treated with anti-MAG IgM ultrastructural myelin alterations were concurrent with activation of the rabbit&amp;#39;s own C to the formation of TCC. Contrary to the immunological and ultrastructural findings obtained in C-sufficient animals, in C6-deficient rabbits injected with anti-MAG IgM no myelin alterations nor C completion were observed. This study identifies anti-MAG IgM as the mediator and the C as the effector of myelin changes observed in the present model and, for extension, in human neuropathies associated with anti-MAG IgM.

Stem Cells, 2009

Mesenchymal stem cells (MSCs) represent a promising therapeutic approach for neurological autoimm... more Mesenchymal stem cells (MSCs) represent a promising therapeutic approach for neurological autoimmune diseases; previous studies have shown that treatment with bone marrow-derived MSCs induces immune modulation and reduces disease severity in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Here we show that intravenous administration of adipose-derived MSCs (ASCs) before disease onset significantly reduces the severity of EAE by immune modulation and decreases spinal cord inflammation and demyelination. ASCs preferentially home into lymphoid organs but also migrates inside the central nervous system (CNS). Most importantly, administration of ASCs in chronic established EAE significantly ameliorates the disease course and reduces both demyelination and axonal loss, and induces a Th2-type cytokine shift in T cells. Interestingly, a relevant subset of ASCs expresses activated α4 integrins and adheres to inflamed brain venules in intravital microscopy experiments. Bioluminescence imaging shows that α4 integrins control ASC accumulation in inflamed CNS. Importantly, we found that ASC cultures produce basic fibroblast growth factor, brain-derived growth factor, and platelet-derived growth factor-AB. Moreover, ASC infiltration within demyelinated areas is accompanied by increased number of endogenous oligodendrocyte progenitors. In conclusion, we show that ASCs have clear therapeutic potential by a bimodal mechanism, by suppressing the autoimmune response in early phases of disease as well as by inducing local neuroregeneration by endogenous progenitors in animals with established disease. Overall, our data suggest that ASCs represent a valuable tool for stem cell–based therapy in chronic inflammatory diseases of the CNS. STEM CELLS 2009;27:2624–2635

Neuropathology and Applied Neurobiology, 1997

Journal of The Neurological Sciences, 1993

We investigated, by immunocytochemistry and immune electron microscopy, the immunophenotype, morp... more We investigated, by immunocytochemistry and immune electron microscopy, the immunophenotype, morphology and functional properties of human peripheral nervous system (PNS) macrophages (M phi) under normal and pathological conditions. Endoneurial M phi disclosed an elongated, ramified morphology, with the main processes oriented along the major axis of nerve fibers; they shared several lineage-related and functional markers with monocyte/macrophages and central nervous system (CNS) microglia, including CD4, CR3, CR4 and FcRIII. In addition, basal expression of HLA-DR antigens was exclusively confined to M phi in normal PNS. In the course of unrelated pathological conditions, resident M phi underwent activation with transformation to hypertrophic cells or foamy phagocytes and up-regulation of the markers expressed in normal conditions; new expression of a macrophagic antigen was detected on activated M phi. In different neuropathies, HLA-DR expression was also detected on non-myelin forming Schwann cells with ultrastructural features indicative of denervation. The present results demonstrate that the human PNS is provided with an intrinsic population of immunocompetent and potentially phagocytic M phi, which represent the peripheral counterpart of CNS microglia.

Journal of Neuroimmunology, 2004

Molecular & Cellular Proteomics, 2008

American Journal of Pathology, 1999

Glia, 2003

The ability of resident cells to induce apoptosis of invading immune cells is a major regulatory ... more The ability of resident cells to induce apoptosis of invading immune cells is a major regulatory factor operating in immune-privileged tissues, including the nervous system. We investigated the cellular and molecular factors participating in modulation of immune response in peripheral nerves, focusing on two cytotoxic pathways: fas ligand (fasL) and perforin. fasL and perforin expression was found by immunochemistry on Schwann cells (Sc) in nerve biopsies from patients with chronic inflammatory demyelinating polyneuritis and on human Sc cultures. Treatment of Sc with tumor necrosis factor (TNF) α and interferon (IFN) γ upregulated the expression of both molecules. In a coculture model, Sc exposed to TNFα or IFNγ were able to induce both apoptotic and lytic injury of T-lymphocytes. Inactivation of fasL with the neutralizing antibody NOK-2 abolished T-cell apoptosis induced by Sc treated with TNFα, but not by Sc treated with IFNγ. Conversely, T-cell lysis was significantly decreased when IFNγ-activated Sc were treated with concanamycin A, which inhibited perforin release. At variance with T-lymphocytes, B-cells were less sensitive to cytokine-treated Sc toxicity. Thus, Sc exposed to inflammatory cytokines have the capacity of inducing selective damage of T-lymphocytes and have the potential of regulating the immune response in the peripheral nervous system. © 2003 Wiley-Liss, Inc.

Italian Journal of Neurological Sciences, 1992

Histochemical, electron microscopy and biochemical studies were performed on muscle biopsy specim... more Histochemical, electron microscopy and biochemical studies were performed on muscle biopsy specimens from 11 AIDS patients treated with zidovudine. A peculiar association of structural abnormalities and mitochondrial dysfunction was found. Focal cytochrome c oxidase (COX) deficiency was evident in muscle sections from 9 patients, 8 of whom had received long-term treatment while one had been treated for 1 month only. Electron microscopy showed changes in number, size and structure of mitochondria. Biochemical studies proved partial COX and succinate cytochrome c reductase (SCR) deficiency in 4 patients; one patient had only reduced SCR activity. Our data confirm that AZT therapy can cause toxic myopathy with mitochondrial dysfunction. Sono state esaminate le biipsie muscolari di 11 pazienti affetti da AIDS in trattamento con Zidovudina. Si è riscontrato una caratteristica associazione di anormalità strutturali delle fibre e di disfunzione mitocondriale. Un deficit focale di citocromo c ossidasi (COX) era presente nelle sezioni muscolari di nove pazienti, otto dei quali avevano subito un trattamento di lunga durata, mentre uno era stato trattato solo per un mese. La microscopia elettronica mostrava modificazioni della struttura, del numero e volume dei mitocrondri. Le indagini biochimiche hanno evidenziato un deficit parziale di COX e di succinato citocromo c reduttasi (SCR) di quattro pazienti, mentre in un paziente riduzione di attività della sola SCR. I nostri dati confermano che la terapia con AZT può causare una miopatia tossica con disfunzione dei mitocondri.