Livia Pasquali

Effects of Alzheimer's disease and mild cognitive impairment on driving ability: a controlled clinical study by simulated driving test

To assess the effects of Alzheimers disease (AD) and Mild Cognitive Impairment (MCI) on simulated car driving ability.

Parkinson’s disease and the gut: a well known clinical association in need of an effective cure and explanation

Abstract  Parkinson’s disease (PD) is a neurodegenerative disorder which leads to severe movement impairment; however, Parkinsonian patients frequently suffer from gastrointestinal (GI) problems which at present are poorly understood, scarcely investigated, and lack an effective cure. Traditionally, PD is attributed to the loss of mesencephalic dopamine‐containing neurons; nonetheless, additional nuclei, such as the dorsal motor nucleus of the vagus nerve and specific central noradrenergic nuclei, are now identified as targets of PD. While the effects of PD on the somatic motor systems are well characterized, the influence on the digestive system still needs to be clarified. Recent findings demonstrate the occurrence of pathological alterations within peripheral neuronal networks in the GI tract of Parkinsonian patients. However, it remains unclear whether a real cell loss occurs, and whether this happens specifically for a subclass of autonomic neurons or if it reflects the sole loss of autonomic nerves. This review summarizes the neurochemical and morphological changes which might be responsible for impaired GI motility. Moreover, we focus on the experimental models to reproduce the altered digestive system of Parkinsonian patients since an experimental model able to mimic such features of PD is required. In the last part of the manuscript, we suggest potential therapeutic targets.

Astrocyte-neuron interactions in neurological disorders.

Astrocytes have long been considered as just providing trophic support for neurons in the central nervous system, but recently several studies have highlighted their importance in many functions such as neurotransmission, metabolite and electrolyte homeostasis, cell signaling, inflammation, and synapse modulation. Astrocytes are, in fact, part of a bidirectional crosstalk with neurons. Moreover, increasing evidence is stressing the emerging role of astrocyte dysfunction in the pathophysiology of neurological disorders, including neurodegenerative disease, stroke, epilepsy, migraine, and neuroinflammatory diseases.

AUTOPHAGY, LITHIUM, AND AMYOTROPHIC LATERAL SCLEROSIS

In this article we provide an overview of the intersection between amyotrophic lateral sclerosis (ALS) and the autophagy pathway and discuss the potential protective effects of lithium through mechanisms that recruit autophagy and other effects. The autophagy pathway is recruited during motor neuron (MN) death both in vitro and in vivo. Despite a few controversial issues concerning the significance (detrimental/protective) of autophagy in ALS, recent findings indicate a protective role. Lithium in low doses is a well‐known autophagy inducer that clears misfolded proteins and altered mitochondria from MNs. Moreover, lithium preserves mitochondria and sustains their genesis. This effect is replicated by rapamycin, which is an autophagy inducer but with a different mechanism from lithium. Lithium also increases the number of Renshaw cells that are affected early during the progression of experimental ALS. Again, lithium has been reported to decrease glial proliferation in the ALS spinal cord and induces sprouting in corticospinal fibers. Muscle Nerve 40: 173–194, 2009

Clinical trials for neuroprotection in ALS.

Owing to uncertainty on the pathogenic mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) riluzole remains the only available therapy, with only marginal effects on disease survival. Here we review some of the recent advances in the search for disease-modifying drugs for ALS based on their putative neuroprotective effetcs. A number of more or less established agents have recently been investigated also in ALS for their potential role in neuroprotection and relying on antiglutamatergic, antioxidant or antiapoptotic strategies. Among them Talampanel, beta-lactam antibiotics, Coenzyme Q10, and minocycline have been investigated. Progress has also been made in exploiting growth factors for the treatment of ALS, partly due to advances in developing effective delivery systems to the central nervous system. A number of new therapies have also been identified, including a novel class of compounds, such as heat-shock protein co-inducers, which upregulate cell stress responses, and agents promoting autophagy and mitochondriogenesis, such as lithium and rapamycin. More recently, alterations of mRNA processing were described as a pathogenic mechanism in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations. This knowledge is expected to improve our understanding of the pathogenetic mechanism in ALS and developing more effective therapies.

Parallel manifestations of neuropathologies in the enteric and central nervous systems

Background  Neurodegenerative diseases may extend outside the central nervous system (CNS) and involve the gastrointestinal (GI) tract. The gut would appear to be a pathological marker for neurodegeneration, as well as a site for studying the pathophysiology of neurodegeneration. In fact, both in the ENS and CNS, misfolded proteins are likely to initiate a process of neurodegeneration. For example, the very same protein aggregates can be detected both in the ENS and CNS. In both systems, misfolded proteins are likely to share common cell‐to‐cell diffusion mechanisms, which may occur through a parallel prion‐like diffusion process. Independently from the enteric or central origin, misfolded proteins may proceed along the following steps, they: (i) form aggregates; (ii) are expressed on plasma membrane; (iii) are secreted extracellularly; (iv) are glycated to form advanced glycation end‐products (AGEs); (v) are internalized through specific receptors placed on neighboring cells (RAGEs); (vi) are cleared by autophagy; and (vii) are neurotoxic. These features are common for a‐synuclein (in Parkinsons disease and other synucleinopathies), β‐amyloid and tau (in degenerative dementia), SOD‐1 and TDP43 (in amyotrophic lateral sclerosis), and PrPsc (in prion diseases). While in some diseases these features are common to both ENS and CNS, in others this remains a working hypothesis.

The importance of nasal resistance in obstructive sleep apnea syndrome: a study with positional rhinomanometry.

The importance of nasal obstruction in the pathogenesis of obstructive sleep apnea syndrome (OSAS) has not yet been totally defined. Numerous studies have reported an association between nasal obstruction and OSAS, but the precise nature of this relationship remains to be clarified. This study was undertaken to evaluate the prevalence of nasal obstruction disorders in a group of OSAS patients. For this purpose, we analyzed the nasal resistance of 36 OSAS patients by performing a traditional basal anterior active rhinomanometry test (AAR) and a positional AAR, with the patient in a supine position. Seven patients had a pathologic nasal resistance in the seated position that increased further in the supine position; 9 patients had normal resistance in the seated position but a pathologic resistance in the supine position. In 20 patients, nasal resistance was normal in both positions. No statistically significant differences in the degree of apnea/hypopnea index (AHI) was found between the 20 patients with normal positional AAR and the 16 with pathologic positional AAR (p = 0.13). Moreover, no statistically significant differences in the degree of AHI was found between the 7 patients with pathologic basal and positional AAR and the 9 patients with normal basal AAR and pathologic positional AAR (p = 0.38).

Alpha-synuclein and autophagy as common steps in neurodegeneration

The major component of Lewy bodies in Parkinsons disease (PD) is alpha-synuclein, which is considered as a substrate of the ubiquitin-proteasome (UP) system, although autophagy seems to be equally involved. Here we discuss the co-existence of alpha-synuclein and proteins belonging to the UP system within autophagic granules, further developing as neuronal inclusions. We hypothesize that, following slight insults, both UP and autophagy are induced; if toxic stimuli are prolonged, these pathways are overwhelmed and cell death occurs. We then indicate a protective role of autophagy in PD and suggest it as a therapeutic target to slow down the progression of the disease.

Genetic or pharmacological blockade of noradrenaline synthesis enhances the neurochemical, behavioral, and neurotoxic effects of methamphetamine.

N‐(2‐chloroethyl)‐N‐ethyl‐2‐bromobenzylamine (DSP‐4) lesions of the locus coeruleus, the major brain noradrenergic nucleus, exacerbate the damage to nigrostriatal dopamine (DA) terminals caused by the psychostimulant methamphetamine (METH). However, because noradrenergic terminals contain other neuromodulators and the noradrenaline (NA) transporter, which may act as a neuroprotective buffer, it was unclear whether this enhancement of METH neurotoxicity was caused by the loss of noradrenergic innervation or the loss of NA itself. We addressed the specific role of NA by comparing the effects of METH in mice with noradrenergic lesions (DSP‐4) and those with intact noradrenergic terminals but specifically lacking NA (genetic or acute pharmacological blockade of the NA biosynthetic enzyme dopamine β‐hydroxylase; DBH). We found that genetic deletion of DBH (DBH−/− mice) and acute treatment of wild‐type mice with a DBH inhibitor (fusaric acid) recapitulated the effects of DSP‐4 lesions on METH responses. All three methods of NA depletion enhanced striatal DA release, extracellular oxidative stress (as measured by in vivo microdialysis of DA and 2,3‐dihydroxybenzoic acid), and behavioral stereotypies following repeated METH administration. These effects accompanied a worsening of the striatal DA neuron terminal damage and ultrastructural changes to medium spiny neurons. We conclude that NA itself is neuroprotective and plays a fundamental role in the sensitivity of striatal DA terminals to the neurochemical, behavioral, and neurotoxic effects of METH.

Impaired oxidative metabolism in exercising muscle from ALS patients

The pathogenic mechanism of selective loss of motor neurones in amyotrophic lateral sclerosis (ALS) is still poorly understood. Recently, research evidence has suggested that mitochondrial dysfunction occurs in central nervous system as well as in peripheral tissues from ALS patients. The aim of our study was to indirectly investigate in vivo oxidative metabolism of exercising muscle in a case history of patients affected by ALS. To this purpose 11 patients, 8 male and 3 female, mean age+/-SD: 52.4+/-11.1 years, performed a bicycle incremental test for the assessment of lactate production. At rest, there was increased lactate concentration in patients: 2.77+/-0.79 vs. 1.48+/-0.49 mmol/l in normal controls (normal range: 0.67-2.47 mmol/l). Analysis of lactate curve during exercise showed a lactate production increase compared to controls. Furthermore, anaerobic lactate threshold was detected at 40-50% of the predicted normal power output, anticipated with respect to both normal subjects and non-ALS chronically denervated controls with comparable motor impairment (60-70%), suggesting that mitochondrial dysfunction can occur in exercising skeletal muscle from ALS patients.