Mitochondrial D-Loop Region Methylation and Copy Number in Peripheral Blood DNA of Parkinson's Disease Patients.

Altered mitochondrial DNA (mtDNA) methylation has been detected in several human pathologies, although little attention has been given to neurodegenerative diseases. Recently, altered methylation levels of the mitochondrial displacement loop (D-loop) region, which regulates mtDNA replication, were observed in peripheral blood cells of Alzheimer's disease and amyotrophic lateral sclerosis patients. However, nothing is yet known about D-loop region methylation levels in peripheral blood of Parkinson's disease (PD) patients. In the current study, we investigated D-loop methylation levels and mtDNA copy number in peripheral blood of 30 PD patients and 30 age- and sex-matched control subjects. DNA methylation analyses have been performed by means of methylation-sensitive high-resolution melting (MS-HRM) and pyrosequencing techniques, while mtDNA copy number was analyzed by quantitative PCR. MS-HRM and pyrosequencing analyses provided very similar D-loop methylation levels in PD patients and control subjects, and no differences between the two groups have been observed. Treatment with L-dopa and duration of the disease had no effect on D-loop methylation levels in PD patients. Additionally, mtDNA copy number did not differ between PD patients and control subjects. Current results suggest that D-loop methylation levels are not altered in peripheral blood of PD patients nor influenced by dopaminergic treatment.

α-Synuclein Heteromers in Red Blood Cells of Alzheimer's Disease and Lewy Body Dementia Patients.

BACKGROUND: Red blood cells (RBCs) contain the majority of α-synuclein (α-syn) in blood, representing an interesting model for studying the peripheral pathological alterations proved in neurodegeneration. OBJECTIVE: The current study aimed to investigate the diagnostic value of total α-syn, amyloid-ß (Aß1-42), tau, and their heteroaggregates in RBCs of Lewy body dementia (LBD) and Alzheimer's disease (AD) patients compared to healthy controls (HC). METHODS: By the use of enzyme-linked immunosorbent assays, RBCs concentrations of total α-syn, Aß1-42, tau, and their heteroaggregates (α-syn/Aß1-42 and α-syn/tau) were measured in 27 individuals with LBD (Parkinson's disease dementia, n = 17; dementia with Lewy bodies, n = 10), 51 individuals with AD (AD dementia, n = 37; prodromal AD, n = 14), and HC (n = 60). RESULTS: The total α-syn and tau concentrations as well as α-syn/tau heterodimers were significantly lower in the LBD group and the AD group compared with HC, whereas α-syn/Aß1-42 concentrations were significantly lower in the AD dementia group only. RBC α-syn/tau heterodimers had a higher diagnostic accuracy for differentiating patients with LBD versus HC (AUROC = 0.80). CONCLUSION: RBC α-syn heteromers may be useful for differentiating between neurodegenerative dementias (LBD and AD) and HC. In particular, RBC α-syn/tau heterodimers have demonstrated good diagnostic accuracy for differentiating LBD from HC. However, they are not consistently different between LBD and AD. Our findings also suggest that α-syn, Aß1-42, and tau interact in vivo to promote the aggregation and accumulation of each other.

Multicenter Study on Sleep and Circadian Alterations as Objective Markers of Mild Cognitive Impairment and Alzheimer's Disease Reveals Sex Differences.

BACKGROUND: Circadian and sleep disturbances are associated with increased risk of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Wearable activity trackers could provide a new approach in diagnosis and prevention. OBJECTIVE: To evaluate sleep and circadian rhythm parameters, through wearable activity trackers, in MCI and AD patients as compared to controls, focusing on sex dissimilarities. METHODS: Based on minute level data from consumer wearable devices, we analyzed actigraphic sleep parameters by applying an electromedical type I registered algorithm, and the corresponding circadian variables in 158 subjects: 86 females and 72 males (42 AD, 28 MCI, and 88 controls). Moreover, we used a confusion-matrix chart method to assess accuracy, precision, sensitivity, and specificity of two decision-tree models based on actigraphic data in predicting disease or health status. RESULTS: Wake after sleep onset (WASO) was higher (p < 0.001) and sleep efficiency (SE) lower (p = 0.003) in MCI, and Sleep Regularity Index (SRI) was lower in AD patients compared to controls (p = 0.004). SE was lower in male AD compared to female AD (p = 0.038) and SRI lower in male AD compared to male controls (p = 0.008), male MCI (p = 0.047), but also female AD subjects (p = 0.046). Mesor was significantly lower in males in the overall population. Age reduced the dissimilarities for WASO and SE but demonstrated sex differences for amplitude (p = 0.009) in the overall population, controls (p = 0.005), and AD subjects (p = 0.034). The confusion-matrices showed good predictive power of actigraphic data. CONCLUSION: Actigraphic data could help identify disease or health status. Sex (possibly gender) differences could impact on neurodegeneration and disease trajectory with potential clinical applications.

Exercise-Related Oxidative Stress as Mechanism to Fight Physical Dysfunction in Neuromuscular Disorders.

Neuromuscular diseases (NMDs) are a group of often severely disabling disorders characterized by dysfunction in one of the main constituents of the motor unit, the cardinal anatomic-functional structure behind force and movement production. Irrespective of the different pathogenic mechanisms specifically underlying these disease conditions genetically determined or acquired, and the related molecular pathways involved in doing that, oxidative stress has often been shown to play a relevant role within the chain of events that induce or at least modulate the clinical manifestations of these disorders. Due to such a putative relevance of the imbalance of redox status occurring in contractile machinery and/or its neural drive in NMDs, physical exercise appears as one of the most important conditions able to positively interfere along an ideal axis, going from a deranged metabolic cell homeostasis in motor unit components to the reduced motor performance profile exhibited by the patient in everyday life. If so, it comes out that it would be important to identify a proper training program, suitable for load and type of exercise that is able to improve motor performance in adaptation and response to such a homeostatic imbalance. This review therefore analyzes the role of different exercise trainings on oxidative stress mechanisms, both in healthy and in NMDs, also including preclinical studies, to elucidate at which extent these can be useful to counteract muscle impairment associated to the disease, with the final aim of improving physical functions and quality of life of NMD patients.

Plasma Levels of Oxidative Stress Markers, before and after BoNT/A Treatment, in Chronic Migraine.

The pathophysiological mechanisms of migraine transformation are debated. Modifications of plasma oxidative stress biomarkers have been described in chronic migraine. OnabotulintoxinA (BoNT/A) treatment, approved for chronic migraine prophylaxis, possibly reduces pain neurotransmitters release and oxidative stress products. Aims of our study were to investigate differences in the levels of selected plasmatic oxidative stress biomarkers (Advanced Oxidation Protein Products (AOPP), Ferric Reducing Antioxidant Power (FRAP), Thiolic Groups (SH)) comparing chronic migraineurs (CM) and healthy controls (HC). We also explored possible clinical and biochemical modifications in the CM group after six months of treatment with BoNT/A. At the baseline, we found higher values of AOPP (p < 0.001), and lower values of SH (p < 0.001) and FRAP (p = 0.005) in the CM group. At the six-month follow-up we found a reduction of AOPP (p < 0.001) and an increase of FRAP (p < 0.001) and SH (p = 0.023) within the CM group. BoNT/A treatment improved migraine symptoms in the CM group. We confirmed previous reports of imbalanced antioxidant mechanisms in chronic migraine showing lower antioxidant capacities in patients than controls. BoNT/A improved the levels of plasma oxidative stress biomarkers and confirmed its role as an effective prophylactic treatment for CM. Other studies should investigate the potential antioxidant properties of BoNT/A treatment.

Potential Diagnostic Value of Red Blood Cells α-Synuclein Heteroaggregates in Alzheimer's Disease.

A plethora of complex misfolded protein combinations have been found in Alzheimer disease (AD) brains besides the classical pathological hallmarks. Recently, α-synuclein (α-syn) and its heterocomplexes with amyloid-ß (Aß) and tau have been suggested to be involved in the pathophysiological processes of neurodegenerative diseases. These pathological features are not limited to the brain, but can be also found in peripheral fluids. In this respect, red blood cells (RBCs) have been suggested as a good model to investigate the biochemical alterations of neurodegeneration. Our aim is to find whether RBC concentrations of α-syn and its heterocomplexes (i.e., α-syn/Aß and α-syn/tau) were different in AD patients compared with healthy controls (HC). The levels of homo- and heteroaggregates of α-syn, Aß and tau, were analyzed in a cohort of AD patients at early stage either with dementia or prodromal symptoms (N = 39) and age-matched healthy controls (N = 39). All AD patients received a biomarker-based diagnosis (low cerebrospinal fluid levels of Aß peptide combined with high cerebrospinal fluid concentrations of total tau and/or phospho-tau proteins; alternatively, a positivity to cerebral amyloid-PET scan). Our results showed lower concentrations of α-syn and its heterocomplexes (i.e., α-syn/Aß and α-syn/tau) in RBCs of AD patients with respect to HC. RBC α-syn/Aß as well as RBC α-syn/tau heterodimers discriminated AD participants from HC with fair accuracy, whereas RBC α-syn concentrations differentiated poorly the two groups. Although additional investigations are required, these data suggest α-syn heteroaggregates in RBCs as potential tool in the diagnostic work-up of early AD diagnosis.

Amyotrophic Lateral Sclerosis and Oxidative Stress: A Double-Blind Therapeutic Trial After Curcumin Supplementation.

OBJECTIVE: To investigate the efficacy of curcumin oral supplementation (600 mg/day, Brainoil), a natural antioxidant compound, in Amyotrophic Lateral Sclerosis (ALS). METHODS: Patients were randomized into two groups: Group A received placebo for 3 months, then Brainoil for the following 3 months, Group B took Brainoil for 6 months. The evaluations were conducted at basal (T0), after 3 months of double blinded Brainoil or placebo treatment (T1), and after the 3 month open-label phase (T2). Clinical evaluations and oxidative stress biomarkers, including oxidative protein products (AOPPs), ferric reducing ability (FRAP), total thiols (T-SH) and lactate, were evaluated, compared to a control group, during an incremental forearm exercise test. RESULTS: Over the entire study Group B showed a stable score of the ALS-FRS-r which decreased in Group A (p<0.01), in parallel with a reduction of AOPPs (p<0.01) which was not detected into Group A. Also FRAP exercise values remained stable in Group B, while in Group A they were reduced without treatment at T1 (0.05T0 exercise lactate was lower compared to Group A (p<0.01). Compared to controls, the whole ALS population showed a greater oxidative stress (p<0.001), those treated with curcumin (Group B) exhibiting decreased exercise AOPPs at T2 with values approaching those of controls. CONCLUSION: Although further studies are needed to confirm these data, treatment with curcumin shows encouraging results indicating a slight slowdown in disease progression, improving aerobic metabolism and oxidative damage, this also contributing to deepen knowledge into the pathogenic mechanisms of ALS.

α-Synuclein Heterocomplexes with ß-Amyloid Are Increased in Red Blood Cells of Parkinson's Disease Patients and Correlate with Disease Severity.

Neurodegenerative disorders (NDs) are characterized by abnormal accumulation/misfolding of specific proteins, primarily α-synuclein (α-syn), ß-amyloid1-42 (Aß1-42) and tau, in both brain and peripheral tissues. In addition to oligomers, the role of the interactions of α-syn with Aß or tau has gradually emerged. Nevertheless, despite intensive research, NDs have no accepted peripheral markers for biochemical diagnosis. In this respect, Red Blood Cells (RBCs) are emerging as a valid peripheral model for the study of aging-related pathologies. Herein, a small cohort (N = 28) of patients affected by Parkinson's disease (PD) and age-matched controls were enrolled to detect the content of α-syn (total and oligomeric), Aß1-42 and tau (total and phosphorylated) in RBCs. Moreover, the presence of α-syn association with tau and Aß1-42 was explored by co-immunoprecipitation/western blotting in the same cells, and quantitatively confirmed by immunoenzymatic assays. For the first time, PD patients were demonstrated to exhibit α-syn heterocomplexes with Aß1-42 and tau in peripheral tissues; interestingly, α-syn-Aß1-42 concentrations were increased in PD subjects with respect to healthy controls (HC), and directly correlated with disease severity and motor deficits. Moreover, total-α-syn levels were decreased in PD subjects and inversely related to their motor deficits. Finally, an increase of oligomeric-α-syn and phosphorylated-tau was observed in RBCs of the enrolled patients. The combination of three parameters (total-α-syn, phosphorylated-tau and α-syn-Aß1-42 concentrations) provided the best fitting predictive index for discriminating PD patients from controls. Nevertheless further investigations should be required, overall, these data suggest α-syn hetero-aggregates in RBCs as a putative tool for the diagnosis of PD.

α-Synuclein Aggregated with Tau and ß-Amyloid in Human Platelets from Healthy Subjects: Correlation with Physical Exercise.

The loss of protein homeostasis that has been associated with aging leads to altered levels and conformational instability of proteins, which tend to form toxic aggregates. In particular, brain aging presents characteristic patterns of misfolded oligomers, primarily constituted of ß-amyloid (Aß), tau, and α-synuclein (α-syn), which can accumulate in neuronal membranes or extracellular compartments. Such aging-related proteins can also reach peripheral compartments, thus suggesting the possibility to monitor their accumulation in more accessible fluids. In this respect, we have demonstrated that α-syn forms detectable hetero-aggregates with Aß or tau in red blood cells (RBCs) of healthy subjects. In particular, α-syn levels and its heteromeric interactions are modulated by plasma antioxidant capability (AOC), which increases in turn with physical activity. In order to understand if a specific distribution of misfolded proteins can occur in other blood cells, a cohort of human subjects was enrolled to establish a correlation among AOC, the level of physical exercise and the concentrations of aging-related proteins in platelets. The healthy subjects were divided depending on their level of physical exercise (i.e., athletes and sedentary subjects) and their age (young and older subjects). Herein, aging-related proteins (i.e., α-syn, tau and Aß) were confirmed to be present in human platelets. Among such proteins, platelet tau concentration was demonstrated to decrease in athletes, while α-syn and Aß did not correlate with physical exercise. For the first time, α-syn was shown to directly interact with Aß and tau in platelets, forming detectable hetero-complexes. Interestingly, α-syn interaction with tau was inversely related to plasma AOC and to the level of physical activity. These results suggested that α-syn heterocomplexes, particularly with tau, could represent novel indicators to monitor aging-related proteins in platelets.

Cross-talk between pathogenic mechanisms in neurodegeneration: the role of oxidative stress in Amyotrophic Lateral Sclerosis.

The mechanisms underlying motoneuron degeneration in amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder that affects the motor system with progressive paralysis, are complex and not yet fully understood. It is generally agreed that ALS is a multifactorial and multisystem disease due not only possibly to genetic causes but also to other factors like oxidative stress, mitochondrial dysfunction, protein aggregation, RNA dysmetabolism, autophagy, and excitotoxicity glutamate-mediate. Altered oxidative stress biomarker profile has been repeatedly reported in ALS patients, which may suggest that abnormal free radical production is relevant in the ALS pathogenesis. This review aims to investigate how oxidative stress can affect other proposed mechanisms of neurodegeneration in ALS.

Gly482Ser PGC-1α Gene Polymorphism and Exercise-Related Oxidative Stress in Amyotrophic Lateral Sclerosis Patients.

The role of exercise in Amyotrophic lateral sclerosis (ALS) pathogenesis is controversial and unclear. Exercise induces a pleiotropic adaptive response in skeletal muscle, largely through the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a transcriptional coactivator that regulates mitochondrial biogenesis and antioxidant defense mechanisms. It has been suggested that a Gly482Ser substitution in PGC-1α has functional relevance in human disorders and in athletic performance. To test this hypothesis, we examined the genotype distribution of PGC-1α Gly482Ser (1444 G > A) in ALS patients to evaluate whether or not the minor serine-encoding allele 482Ser is involved in oxidative stress responses during physical exercise. We genotyped 197 sporadic ALS patients and 197 healthy controls in order to detect differences in allelic frequencies and genotype distribution between the two groups. A total of 74 ALS patients and 65 controls were then comparatively assessed for plasmatic levels of the oxidative stress biomarkers, advanced oxidation protein products, ferric reducing ability and thiol groups. In addition a subgroup of 35 ALS patients were also assessed for total SOD and catalase plasmatic activity. Finally in 28 ALS patients we evaluated the plasmatic curve of the oxidative stress biomarkers and lactate during an incremental exercise test. No significant differences were observed in the genotype distribution and allelic frequency in ALS patients compared to the controls. We found significant increased advanced oxidation protein products (p < 0.001) and significant decreased ferric reducing ability (p < 0.001) and thiol groups (p < 0.001) in ALS patients compared to controls. When comparing different genotypes of PGC-1α, no relation between Gly482Ser polymorphism and oxidative stress biomarker levels was detected in resting conditions. On the other hand, when considering exercise performance, lactate levels were significantly higher (between p < 0.01 and p < 0.001) and greater protein oxidative products were found in AA (Ser482Ser) compared to GG (Gly482Gly) and GA (Gly482Ser) ALS patients. Our findings highlight the importance and confirm the involvement of oxidative stress in ALS pathogenesis. Although not associated with 1444 G > A SNP, ALS patients with Gly482Ser allelic variant show increased exercise-related oxidative stress. This thus highlights the possible role of this antioxidant defense transcriptional coactivator in ALS.

Evidences of Reduced Antioxidant Activity in Patients With Chronic Migraine and Medication-Overuse Headache.

BACKGROUND: Migraine is a complex multifactorial, neurobiological disorder, whose pathogenesis is not fully understood, nor are the mechanisms associated with migraine transformation from episodic to chronic pattern. A possible role of impaired oxidative mitochondrial metabolism in migraine pathogenesis has been hypothesized, and increased levels of peripheral markers of oxidative stress have been reported in migraine patients, although the literature data are limited and heterogeneous. OBJECTIVES: The aim of this cross-sectional study was to determine plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power and total plasmatic thiol groups, all plasmatic markers related to oxidative stress, in a sample of chronic migraine patients and medication-overuse headache, compared to a control group of healthy subjects. METHODS: Thirty-three patients with a diagnosis of both chronic migraine and medication-overuse headache (International Classification of Headache Disorders,3rd edition, beta version) and 33 healthy, headache-free subjects were enrolled. Patients with comorbid/coexisting conditions were excluded, as well as patients in treatment with migraine preventive drugs. Plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power, and total thiol groups were determined in migraine patients and controls; moreover, oxidative stress biomarkers were compared in migraine patients with triptan compared to non-steroidal anti-inflammatory drug overuse. RESULTS: The statistical analysis showed significantly lower levels of ferric-reducing antioxidant power and total plasmatic thiol groups, both expression of antioxidant power, in patients with chronic migraine and medication-overuse headache compared to controls (respectively, ferric antioxidant power median [interquartile range] 0.53 [0.22] vs 0.82 [0.11] mmol/L, P < .001; total thiol groups 0.25 [0.08] vs 0.51 [0.11] µmol/L, P < .001). Moreover, no statistically significant differences in oxidative stress biomarkers were detected between patients with triptan and nonsteroidal anti-inflammatory drug overuse. CONCLUSIONS: The data from the present study suggest that antioxidant capacity is lower in chronic migraine patients and medication-overuse headache compared to healthy headache-free subjects, with no differences between patients with triptan or nonsteroidal anti-inflammatory drug overuse. Further investigation is certainly necessary in order to define the causal or consequential role of an imbalance between pro-oxidants and antioxidant defenses in migraine pathogenesis and "chronification" and the possible therapeutic implications in clinical practice.

Twinkle mutation in an Italian family with external progressive ophthalmoplegia and parkinsonism: a case report and an update on the state of art.

The objective is to describe the clinical phenotype and genetic basis of a family with autosomal dominant progressive external ophthalmoplegia and parkinsonism with a Twinkle mutation. The proband, an 82 years old female, reported since childhood bilateral eyelid ptosis, ophthalmoplegia, sensorineural hypoacusis, mild depression since she was 45, with a positive familiar anamnesis of eyelid ptosis (father, two sisters and a son). She developed mild bilateral parkinsonism with a moderate clinical response to levodopa. The (123)I-FP-CIT SCAN evidenced a marked bilateral putaminal reduction and moderate caudate uptake reduction. Her 79 years old sister reported eyelid ptosis since she was 45 with ophthalmoplegia and developed a mild bilateral rest and postural tremor with moderate right arm plastic hypertonia when she was 76. The parkinsonism was confirmed with (123)I-FP-CIT SCAN. One of the two sons presented eyelid ptosis since he was 30 years old, with peripheral neuropathy with biopsy evidence of myopathy. We identified a G1750A mutation in the c10orf2 gene in the three patients. Mitochondrial dysfunction has been implicated in the pathogenesis of sporadic, idiopathic Parkinson disease (PD). In some cases, mitochondrial DNA primary genetic abnormalities or more commonly secondary rearrangements due to polymerase gamma (POLG) gene mutation can directly cause parkinsonism. Parkinsonism has been reported as a rare symptom associated to Twinkle (c10orf2). Parkinsonism has to be investigated in patients with PEO with analysis of Twinkle mutation.

Effects of aerobic training on exercise-related oxidative stress in mitochondrial myopathies.

In mitochondrial myopathies with respiratory chain deficiency impairment of energy cell production may lead to in excess reactive oxygen species generation with consequent oxidative stress and cell damage. Aerobic training has been showed to increase muscle performance in patients with mitochondrial myopathies. Aim of this study has been to evaluate, in 7 patients (6 F e 1M, mean age 44.9 ± 12.1 years) affected by mitochondrial disease, concomitantly to lactate exercise curve, the occurrence of oxidative stress, as indicated by circulating levels of lipoperoxides, in rest condition and as effect of exercise, and also, to verify if an aerobic training program is able to modify, in these patients, ox-redox balance efficiency. At rest and before training blood level of lipoperoxides was 382.4 ± 37.8 AU, compared to controls (318.7 ± 63.8; P<0.05), this corresponding to a moderate oxidative stress degree according to the adopted scale. During incremental exercise blood level of lipoperoxides did not increase, but maintained significantly higher compared to controls. After an aerobic training of 10 weeks the blood level of lipoperoxides decreased by 13.7% at rest (P<0.01) and 10.4%, 8.6% and 8.5% respectively at the corresponding times during the exercise test (P=0.06). These data indicate that, in mitochondrial patients, oxidative stress occurs and that an aerobic training is useful in partially reverting this condition.

DNMT3B promoter polymorphisms and risk of late onset Alzheimer's disease.

The vast majority of Alzheimer's disease (AD) are late-onset forms (LOAD) likely due to the contribution of genetic, environmental, and stochastic factors, superimposed on a physiologically age-related decline of neuronal functions. Increasing evidence indicates epigenetic modifications in LOAD brains, and many of the environmental factors associated with AD risk, such as heavy metals and dietary factors, are able to modify the epigenome. There is also indication that environmentally-induced early life modifications of the genome during embryogenesis and brain development could contribute to the development of the disease later in life. DNA methyltransferase 3b (DNMT3b) is an enzyme involved in de novo methylation of the genome during embryogenesis, expressed in progenitor cells during neurogenesis. In the present study we evaluated two functional DNMT3B promoter polymorphisms, namely -149 C > T (rs2424913) and - 579 G > T (rs1569686), as candidate LOAD risk factors. Our analysis of 376 Italian LOAD patients and 308 matched controls revealed no difference in allele frequencies between the case an the control group (OR = 1.10 (0.88-1.39) for rs2424913, and OR = 1.02 (0.81-1.28) for rs1569686). Also the genotype distributions of both polymorphisms were closely similar between groups, and no significant effect on disease age at onset was observed. Overall, present results do not support a major role for rs2424913 or rs1569686 in LOAD pathogenesis.

Strategies for clinical approach to neurodegeneration in Amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and ultimately fatal neurodegenerative disorder of unknown aetiology that involves the loss of upper and lower motor neurons in the cerebral cortex, brainstem and spinal cord. Significant progress in understanding the cellular mechanisms of motor neuron degeneration in ALS has not been matched with the development of therapeutic strategies to prevent disease progression, and riluzole remains the only available therapy, with only marginal effects on disease survival. More recently alterations of mRNA processing in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations have provided important insights into the molecular networks implicated in the disease pathogenesis. Here we review some of the recent progress in promoting therapeutic strategies for neurodegeneration.

Association study between XRCC1 gene polymorphisms and sporadic amyotrophic lateral sclerosis.

The aim of the present study was to investigate the possible contribution of three common functional polymorphisms in the DNA repair protein X-ray repair cross-complementing group 1 (XRCC1), namely Arg194Trp (rs1799782), Arg280His (rs25489) and Arg399Gln (rs25487), to sporadic amyotrophic lateral sclerosis (SALS). We genotyped 206 Italian SALS patients and 203 matched controls for XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms by means of PCR/RFLP technique, searching for association between any of the studied polymorphisms and disease risk, age and site of onset. We observed a statistically significant difference in XRCC1 Gln399 allele frequencies between SALS cases and controls (0.39/0.28; p=0.001). The present study suggests that the XRCC1 Arg399Gln polymorphism might contribute to SALS risk.

Lack of association between the APEX1 Asp148Glu polymorphism and sporadic amyotrophic lateral sclerosis.

Impairments in DNA repair enzymes have been observed in amyotrophic lateral sclerosis (ALS) tissues, particularly in the activity of the apurinic/apyrimidinic endonuclease 1 (APEX1). Moreover, it was suggested that the common APEX1 Asp148Glu polymorphism might be associated with ALS risk. To further address this question we performed the present study aimed at evaluating the contribution of the APEX1 Asp148Glu polymorphism in sporadic ALS (sALS) risk and clinical presentation, including age and site of onset and disease progression. We screened 134 sALS Italian patients and 129 matched controls for the presence of the APEX1 Asp148Glu polymorphism. No difference in APEX1 Asp148Glu allele and genotype frequencies was found between the groups, nor was the polymorphism associated with age and site of onset or disease progression. Present results do not support a role for the APEX1 Asp148Glu polymorphism in sALS pathogenesis in the Italian population.

Advances in molecular diagnostics for mitochondrial diseases.

BACKGROUND: Mitochondrial disorders (MD) are diseases caused by impairment of the mitochondrial respiratory chain. Phenotypes are polymorphous and may range from pure myopathy to multisystemic disorders. The genetic defect can be located on mitochondrial or nuclear DNA. At present, diagnosis of MD requires a complex approach: measurement of serum lactate, electromyography, muscle histology and enzymology, and genetic analysis. Magnetic resonance spectroscopy allows the assessment of tissue metabolic alterations, thus providing useful information for the diagnosis and monitoring of MD. Molecular soluble markers of mitochondrial dysfunction, at rest and during exercise, can identify the impairment of the aerobic system in MD, but a reliable biomarker for the screening or diagnosis of MD is still needed. OBJECTIVE: Molecular and genetic characterization of MD, together with other experimental approaches, contribute to add new insights to these diseases. Here, the role and advances of diagnostic techniques for MD are reviewed. CONCLUSION: Possible applications of the results obtained by new molecular investigative approaches could in future guide therapeutic strategies.