Raffaello Nemni

Peripheral neuropathy in hepatitis C virus infection with and without cryoglobulinaemia

Objectives: Hepatitis C virus (HCV) infection is often associated with cryoglobulinaemia (CG). Peripheral neuropathy (PN) is a comparatively common complication of CG associated with HCV infection and it is thought to be attributable to nerve ischaemia. Only few HCV CG patients with PN have been reported. The recent finding of HCV RNA in nerve biopsy specimens has suggested a possible direct role of HCV in the pathogenesis of PN. The authors studied 51 HCV patients to determine the prevalence of CG and to clarify the possible mechanism by which HCV determines the PN. Methods: All the patients were studied clinically, by laboratory tests and electrophysiologically. Twenty eight patients underwent sural nerve biopsy where both morphological and morphometric evaluation of the biopsy specimen was performed, as well as statistical analysis. Results: CG was found in 40 of 51 cases (78%). Polyneuropathy was significantly prevalent in CG+ patients compared with CG− (18 of 40 compared with 1 of 11 patients; p=0.01). HCV CG− patients more frequently developed well defined mononeuropathy or multiple neuropathy when compared with HCV CG+ (10 of 11 compared with 22 of 40; p<0.03). HCV CG+ patients showed significantly higher proportion of rheumatoid factor positivity (p<0.001) and low C4 levels (p=0.001). Nerve biopsy was performed in 25 of 40 HCV CG+ patients and in 3 of 11 HCV CG− patients: epineurial vasculitis was present in 8 of 25 HCV CG+ (32%) and in 2 of 3 HCV CG−. Differential fascicular loss of axons was found in 10 of 25 CG+ (40%) and 1 of 3 CG−, signs of both demyelination and axonal degeneration were present in 7 of 25 CG+ (28%). No significant difference was found in neuropathological features, while histometrical analysis disclosed more severe involvement in CG+ patients. Conclusions: These findings suggest that the presence of CG is a negative predictive factor for the associated PN. Morphological findings in the sural nerve from HCV CG− and CG+ are consistent with an ischaemic mechanism of nerve damage and are against a direct role of the virus in causing the associated PN.

Locomotor Function in the Early Stage of Parkinson's Disease

The cardinal motor symptoms of Parkinsons disease (PD) have been widely investigated with particular reference to abnormalities of steady-state walking. The great majority of studies, however are related to severe forms of PD patients (phases of Hoehn and Yahr scale), where locomotor abnormalities are clearly manifested. Goal of the present study was to quantitatively describe locomotor symptoms in subjects with mild PD. Accordingly, a multitask protocol involving instrumental analysis of steady-state linear walking, initiation of gait, and turning while walking was applied to a group of patients with idiopathic PD in their early clinical stage (phases 1 and 2 of Hoehn and Yahr scale), as well as in age-matched elderly controls. Kinematic, kinetic, and myoelectric measures were obtained by optoelectronic motion analysis, force platform, and telemetric electromyography. Results in PD patients showed a tendency to bradykinetic gait, with reduction of walking speed and cadence. Impairments of gait initiation consisted in reduction of the backward shift of the center of pressure (CoP) and prolongation of the stepping phase. Alterations of the turning task were more consistent and included delayed reorientation of the head toward the new direction, altered head-upper trunk rotational strategy, and adoption of a greater number of steps to complete the turning. It is concluded that patients in the early stage of PD reveal mild alterations of steady-state linear walking and more significant anomalies in the transitional conditions, especially during changes in the travel direction. Quantitative analysis of nonstationary locomotor tasks might be a potentially useful starting point for further studies on the pathophysiology of PD.

Late-onset cerebellar ataxia with hypogonadism and muscle coenzyme Q10 deficiency

Two brothers had late-onset progressive ataxia, cerebellar atrophy, and hypergonadotropic hypogonadism associated with coenzyme Q10 (CoQ10) deficiency in skeletal muscle. Both patients improved on high-dose CoQ10 supplementation, stressing the importance of CoQ10 deficiency in the differential diagnosis of cerebellar ataxia, even when onset is late.

The NLRP3 and NLRP1 inflammasomes are activated in Alzheimer's disease

BackgroundInterleukin-1 beta (IL-1β) and its key regulator, the inflammasome, are suspected to play a role in the neuroinflammation observed in Alzheimer’s disease (AD); no conclusive data are nevertheless available in AD patients.ResultsmRNA for inflammasome components (NLRP1, NLRP3, PYCARD, caspase 1, 5 and 8) and downstream effectors (IL-1β, IL-18) was up-regulated in severe and MILD AD. Monocytes co-expressing NLRP3 with caspase 1 or caspase 8 were significantly increased in severe AD alone, whereas those co-expressing NLRP1 and NLRP3 with PYCARD were augmented in both severe and MILD AD. Activation of the NLRP1 and NLRP3 inflammasomes in AD was confirmed by confocal microscopy proteins co-localization and by the significantly higher amounts of the pro-inflammatory cytokines IL-1β and IL-18 being produced by monocytes. In MCI, the expression of NLRP3, but not the one of PYCARD or caspase 1 was increased, indicating that functional inflammasomes are not assembled in these individuals: this was confirmed by lack of co-localization and of proinflammatory cytokines production.ConclusionsThe activation of at least two different inflammasome complexes explains AD-associated neuroinflammation. Strategies targeting inflammasome activation could be useful in the therapy of AD.

A pilot trial of low-dose naltrexone in primary progressive multiple sclerosis:

A sixth month phase II multicenter-pilot trial with a low dose of the opiate antagonist Naltrexone (LDN) has been carried out in 40 patients with primary progressive multiple sclerosis (PPMS). The primary end points were safety and tolerability. Secondary outcomes were efficacy on spasticity, pain, fatigue, depression, and quality of life. Clinical and biochemical evaluations were serially performed. Protein concentration of β-endorphins (BE) and mRNA levels and allelic variants of the μ-opiod receptor gene (OPRM1) were analyzed. Five dropouts and two major adverse events occurred. The remaining adverse events did not interfere with daily living. Neurological disability progressed in only one patient. A significant reduction of spasticity was measured at the end of the trial. BE concentration increased during the trial, but no association was found between OPRM1 variants and improvement of spasticity. Our data clearly indicate that LDN is safe and well tolerated in patients with PPMS.

Polyneuropathy in hypothyroidism: clinical, electrophysiological and morphological findings in four cases.

Clinical, neurophysiological and morphological studies of four patients with polyneuropathy and secondary hypothyroidism are reported. Neurophysiological studies revealed signs of muscle denervation and reduction of conduction velocity in all the patients. Sural nerve biopsies showed axonal degeneration in all cases but one. All the patients were treated with replacement therapy and clinical symptomatology and neurophysiological parameters improved in all patients.

Increased activity of Th-17 and Th-9 lymphocytes and a skewing of the post-thymic differentiation pathway are seen in Alzheimer’s disease

Inflammatory mediators are responsible for the neuroinflammation observed in Alzheimers disease (AD), a phenomenon that might be the culprit of disease or, possibly, a reaction to pathology. To better investigate inflammation in AD we performed an extensive immunophenotypic and functional analysis of amyloid-beta (Aβ) stimulated T lymphocytes in patients with a diagnosis of AD comparing data to those obtained in individuals with mild cognitive impairment (MCI) or aged-matched healthy individuals (HC). Results showed that IL-21- and IL-9-producing Aβ stimulated CD4(+) T cells, as well as IL-23- and IL-6-producing monocytes and CD4(+) T cells expressing the RORγ and NFATc1 transcriptional factors (TF), were significantly increased, whereas IL-10-producing monocytes were decreased in AD. Notably, GATA-3 TF-expressing CD4(+) T lymphocytes were significantly increased in MCI alone. Analysis of the post-thymic differentiation pathway indicated that Aβ specific naïve and central memory CD4(+) T lymphocytes were diminished whereas effector memory and terminally differentiated CD4(+) T lymphocytes were increased in AD and MCI compared to HC. Data herein indicate that cytokines (IL-21, IL-6, IL-23) and TF (RORγ) involved in the differentiation of Th-17 cells), as well as cytokines (IL-21, IL-22) generated by such cells, and IL-9, produced by Th-9 cells, are significantly increased in AD. This is accompanied by a shift of post-thymic differentiation pathways favoring the accumulation of differentiated, effector T lymphocytes. These data shed light on the nature of AD-associated neuroinflammation. A better understanding of the complexity of this phenomenon could facilitate the search for novel therapeutic strategies.

PD1 Negative and PD1 Positive CD4+ T Regulatory Cells in Mild Cognitive Impairment and Alzheimer's Disease

Regulatory T lymphocytes (Treg) play a fundamental importance in modulating the relative balance between inflammation and immune tolerance, and alterations of these cells are observed in inflammatory diseases. To better characterize the neuroinflammatory processes suggested to be associated with Alzheimers disease (AD) and to clarify the possible role of Treg cells in this process, we extensively analyzed these cells (CD4 + CD25highFoxp3+) in patients with either severe AD (n=25) or mild cognitive impairment (MCI) (n=25), comparing the results with those of two groups of healthy controls (HC) (n=55). Because the intra- or extracellular expression of programmed death receptor 1 (PD1) identifies functionally diverse subsets of Treg we also analyzed such subpopulations. Results showed that, whereas both Treg and PD1pos Treg are increased in MCI and AD patients compared to HC, PD1neg Treg, the subpopulation of Treg cells endowed with the strongest suppressive ability, are significantly augmented in MCI patients alone. In these patients amyloid-β-stimulated-T cells proliferation was reduced and Treg-mediated suppression was more efficient compared to both AD and HC. The observation that PD1neg Treg, cells are increased in MCI patients reinforces the inflammatory origin of AD and supports a possible beneficial role of these cells in MCI that is lost in patients with full-blown AD.

Effect of chronic treatment with recombinant interleukin-2 on the central nervous system of adult and old mice

We have studied the effects of chronic treatment with recombinant interleukin-2 on the central nervous system of adult and old mice. Treatment with high doses of recombinant interleukin-2, on a schedule similar to that used in humans, was started at the age of 4 and 17 months, respectively, and ended 3 months later. At that time, all the mice were tested for acquisition of a passive-avoidance task and then sacrificed for histological examination. Three of the four groups (treated and control adults and control old mice) did not differ from one another in task performance or neuron density in frontal cortex, cerebellum, dentate gyrus or CA1-2, CA3, CA4 hippocampal areas. The old treated mice were unique in showing impairment of the mnesic functions and marked neuronal cell loss and degenerative changes limited to the hippocampal regions. Immunohistochemical studies did not show any significant amount of immunoglobulins in affected areas. Our results suggest that in old mice the impairment of the mnesic functions after recombinant interleukin-2 administration is due to hippocampal neuronal damage.

Humoral and cellular immune responses to myelin protein peptides in chronic inflammatory demyelinating polyradiculoneuropathy

Objectives: Evidence that chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease was sought, by studying cellular and humoral immune responses to peripheral nerve myelin proteins. Methods: 40 CIDP, 36 healthy control subjects (HC) and subjects with non-immune mediated neuropathies (other neuropathies, ON) for antibodies were studied by ELISA and cellular responses by cytokine ELISPOT (INFγ, IL10) and ELISA (IL17) to synthetic peptides representing P0, P2 and PMP22. Results: Antibodies to P0, P2 or PMP22 peptides were detected in only a minority of CIDP, both not treated (nT-CIDP) and treated (T-CIDP). IgG antibodies to P280–105 were significantly more frequent in CIDP than in HC (4/30 vs 0/32; p<0.05) but the difference from ON (1/25) was not significant. In ELISPOT assays, IFNγ was detected at a low frequency in CIDP and did not differ from HC or ON. In contrast, IL10 responses against P21–85 were more frequent in nT and T-CIDP (7/24 and 3/16) than HC (0/36; p<0.001 and p<0.05, respectively). The production of IL17 in cell-culture supernatants was not increased. Conclusions: Antibodies to non-conformational antigenic epitopes of myelin proteins rarely occur in CIDP. None of the myelin protein peptides elicited IFNγ responses, but P2 elicited IL10 responses significantly more often in CIDP patients than in controls. This reactivity may be part of an antigen-specific Th2 type pathogenetic or regulatory mechanism or represent a transitory epiphenomenon due to nerve damage. In our study, P2 was the protein antigen most likely to be involved in the aberrant immune responses in CIDP.