Respiratory complex I dysfunction due to mitochondrial DNA mutations shifts the voltage threshold for opening of the permeability transition pore toward resting levels

We have studied mitochondrial bioenergetics in HL180 cells (a cybrid line harboring the T14484C/ND6 and G14279A/ND6 mtDNA mutations of Leber hereditary optic neuropathy, leading to an approximately 50% decrease of ATP synthesis) and XTC.UC1 cells (derived from a thyroid oncocytoma bearing a disruptive frameshift mutation in MT-ND1, which impairs complex I assembly). The addition of rotenone to HL180 cells and of antimycin A to XTC.UC1 cells caused fast mitochondrial membrane depolarization that was prevented by treatment with cyclosporin A, intracellular Ca2+ chelators, and antioxidant. Both cell lines also displayed an anomalous response to oligomycin, with rapid onset of depolarization that was prevented by cyclosporin A and by overexpression of Bcl-2. These findings indicate that depolarization by respiratory chain inhibitors and oligomycin was due to opening of the mitochondrial permeability transition pore (PTP). A shift of the threshold voltage for PTP opening close to the resting potential may therefore be the underlying cause facilitating cell death in diseases affecting complex I activity. This study provides a unifying reading frame for previous observations on mitochondrial dysfunction, bioenergetic defects, and Ca2+ deregulation in mitochondrial diseases. Therapeutic strategies aimed at normalizing the PTP voltage threshold may be instrumental in ameliorating the course of complex I-dependent mitochondrial diseases.

The antioxidant function of Bcl-2 preserves cytoskeletal stability of cells with defective respiratory complex I

Human thyroid carcinoma XTC.UC1 cells harbor a homoplasmic frameshift mutation in the MT-ND1 subunit of respiratory complex I. When forced to use exclusively oxidative phosphorylation for energy production by inhibiting glycolysis, these cells triggered a caspase-independent cell death pathway, which was associated to a significant imbalance in glutathione homeostasis and a cleavage of the actin cytoskeleton. Overexpression of the anti-apoptotic Bcl-2 protein significantly increased the level of endogenous reduced glutathione, thus preventing its oxidation after the metabolic stress. Furthermore, Bcl-2 completely inhibited actin cleavage and increased cell adhesion, but was unable to improve cellular viability. Similar effects were obtained when XTC.UC1 cells were incubated with exogenous glutathione. We hence propose that Bcl-2 can safeguard cytoskeletal stability through an antioxidant function.

Neuropsychiatric symptoms in 921 elderly subjects with dementia: a comparison between vascular and neurodegenerative types

OBJECTIVE

i) to describe the neuropsychiatric profile of elderly subjects with dementia by comparing vascular (VaD) and degenerative dementias, i.e. dementia with Lewy bodies (DLB) and Alzheimer's disease (AD); ii) to assess whether the severity and type of dementia are associated with clinically relevant neuropsychiatric symptoms (CR-NPS).

METHOD

One hundred and thirty-one out-patients with VaD, 100 with DLB and 690 with AD were studied. NPS were evaluated by the neuropsychiatric inventory (NPI).

RESULTS

Vascular dementia had lower total and domain-specific NPI scores and a lower frequency of CR-NPS than AD and DLB, for which frequency of CR-NPS increased significantly with disease severity, particularly in AD. Logistic regression analysis showed that a higher CDR score and a diagnosis of degenerative dementia were independently associated with CR-NPS.

CONCLUSION

Vascular dementia is associated less with CR-NPS than AD and DLB. Frequency of CR-NPS increases with disease severity in AD and, to a lesser extent, in DLB.

Influence of comorbidity and cognitive status on instrumental activities of daily living in amnestic mild cognitive impairment: results from the ReGAl project

OBJECTIVES

To investigate whether amnestic mild cognitive impairment (aMCI) is characterised by restriction in instrumental activities of daily living (IADL). Further, to examine the role of comorbidity and cognitive performance on IADL changes in aMCI subjects.

METHODS

The study included 132 subjects with aMCI and 249 subjects with no cognitive impairment (NCI), consecutively enrolled as outpatients in a multicentric Italian clinical-based study, the ReGAl Project. All subjects underwent a comprehensive evaluation including clinical examination, laboratory screening, neuroimaging and cognitive and behavioral assessments. Functional status was evaluated by the Lawton's Instrumental Activities of Daily Living (IADL) scale. Comorbidity was evaluated by the Cumulative Illness Rating Scale (CIRS). Cognitive evaluation included tests assessing episodic memory, language, attention/executive functioning and praxis, as well as the the Mini-Mental State Examination (MMSE) as a measure of global cognition.

RESULTS

Subjects with aMCI had higher IADL changes than NCI. Among IADL items, aMCI subjects showed a significant impairment in shopping, taking drugs, and handling economy; however also NCI had minor IADL changes regarding cooking, washing and cleaning. IADL restriction in aMCI subjects was significantly associated with cognitive performance, mainly related to executive functioning, but not with comorbidity. On the contrary, in NCI sensory impairment accounts for slight IADL changes.

CONCLUSION

In aMCI subjects a mild degree of cognitive deterioration has a stronger impact on IADL than somatic comorbidity. Current diagnostic criteria for MCI should include a mild impairment in IADL.

Vascular risk factors in mild cognitive impairment subtypes. Findings from the ReGAl project

BACKGROUND AND AIM

To investigate the role of vascular risk factors in different subtypes of mild cognitive impairment (MCI) in a multicentric, clinic-based, cross-sectional study.

METHODS

Two-hundred and seven subjects with MCI were included in the study: 33 with single non-memory MCI (snmMCI), 42 with multiple-domain amnestic MCI (mdMCI-a) and 132 with amnestic MCI (aMCI). Several clinical vascular risk factors and magnetic resonance imaging (MRI) brain lesions were evaluated.

RESULTS

snmMCI showed a higher frequency of ischaemic heart disease and of transient ischaemic attack (TIA)/stroke, a higher Hachinski ischaemic score and a higher frequency of white-matter lesions on MRI compared to aMCI. Subjects with mdMCI-a showed clinical characteristics similar to aMCI, except for a higher frequency of a history of TIA/stroke.

CONCLUSION

Our findings suggest that snmMCI may be considered a vascular cognitive disorder.

High-performance liquid chromatographic method for the simultaneous determination of 24 fragrance allergens to study scented products

The European legislation on cosmetic products has recently required the declaration of 26 compounds (24 volatile chemicals and 2 natural extracts) on the label of final products when exceeding a stipulated cut-off level. In this work a rapid reliable and specific RP-HPLC method coupled with diode array detector (DAD) has been developed for the simultaneous determination and quantification of the 24 volatile chemicals: amyl cinnamal, benzyl alcohol, cinnamyl alcohol, citral, eugenol, hydroxy-citronellal, isoeugenol, amylcinnamyl alcohol, benzyl salicylate, cinnamal, coumarin, geraniol, Lyral (hydroxy-methylpentylcyclohexene carboxaldehyde), anisyl alcohol, benzyl cinnamate, farnesol, Lilial (2-(4-tert-butylbenzyl)propionaldehyde) linalool, benzyl benzoate, citronellol, hexyl cinnamal, limonene, methylheptin carbonate, alpha-isomethyl ionone (3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one). The 24 analytes were appropriately separated over a running time of 40 min, on a C18 column using a simple gradient elution (acetonitrile/water) with flow rate from 0.7 to 1.0 ml/min and UV acquisition at 210, 254 and 280 nm. All calibration curves showed good linearity (r2>0.99) within test ranges. The method was successfully applied to the qualitative and quantitative determination of the potential allergens in four commercial scented products, with satisfactory accuracy and precision. The results indicated that this simple and efficient method can be used for quality assessment of complex matrices such us cosmetic scented products.

Hallmarks of protein oxidative damage in neurodegenerative diseases: focus on Alzheimer’s disease

The pathogenesis of several neurodegenerative diseases, including Alzheimer's disease, has been linked to a condition of oxidative and nitrosative stress, arising from the imbalance between increased reactive oxygen species (ROS) and reactive nitrogen species (RNS) production and antioxidant defences or efficiency of repair or removal systems. The effects of free radicals are expressed by the accumulation of oxidative damage to biomolecules: nucleic acids, lipids and proteins. In this review we focused our attention on the large body of evidence of oxidative damage to protein in Alzheimer's disease brain and peripheral cells as well as in their role in signalling pathways. The progress in the understanding of the molecular alterations underlying Alzheimer's disease will be useful in developing successful preventive and therapeutic strategies, since available drugs can only temporarily stabilize the disease, but are not able to block the neurodegenerative process.

Different antioxidant profiles in Italian centenarians: the Sardinian peculiarity

In this study, 153 Italian centenarians from four different geographical areas, including Modena (northern Italy), Ancona (central Italy), Perugia (central Italy) and Sardinia island (AKEA Project) were enrolled. Plasma levels of vitamin C, uric acid, vitamin A and vitamin E as well as the activities of superoxide dismutase and glutathione peroxidase were measured. Subjects were compared to a younger control population of the same areas, divided into three age groups: <or=60; 61-80 and 81-99 years. The main result of this study is that, whereas in Italian population elevated levels of plasma vitamins A and E seem to be important for longevity, this do not apply to centenarians from Sardinia, in which probably other factors play a more important role.

Antioxidant enzyme activities in healthy old subjects: influence of age, gender and zinc status

Enzymatic activities of plasma superoxide dismutase (pSOD), catalase (CAT) and glutathione peroxidase (GPx) and erythrocyte superoxide dismutase (eSOD) were assayed in 981 healthy community dwelling old subjects participating in the Zincage Project. The relationship between antioxidant enzyme activities and, respectively, gender, age and zinc status were assessed. eSOD activity was higher in nonagenarians than in 80 year old subjects. Plasma Zn was lower in nonagenarians compared with younger subjects. The prevalence of Zn deficiency increased with age, with normal Zn levels observed in about 80% of adult subjects and only in 37% of the nonagenarians. Women showed higher eSOD and CAT activities compared to men, whereas plasma Zn was higher in men than in women. There was a positive correlation between eSOD activity and age and a negative correlation between eSOD activity and plasma Zn concentrations. An inverse correlation was also found between plasma Zn concentration and age. Further studies on different aspects of Zn metabolism--intake, plasma concentration, peripheral cell concentration, activity and amount of Zn-dependent enzymes--are warranted.

Association between apolipoprotein E epsilon4 allele and apathy in probable Alzheimer's disease

OBJECTIVE

There have been inconclusive results to date on the association between the Apolipoprotein E (ApoE) genotype and neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). We investigated whether ApoE epsilon4 allele is associated with NPS in probable AD.

METHOD

Data for 197 subjects with probable AD were analysed. The Neuropsychiatric Inventory was used to evaluate the frequency and severity of NPS. Multiple logistic regression models were used to test the association between ApoE genotype and NPS in AD.

RESULTS

The ApoE epsilon3/3 genotype was present in 52.3%, epsilon3/4 in 44.1%, and epsilon4/4 in 3.6% of patients. ApoE epsilon4 carriers showed a higher frequency of apathy than non-carriers. After multiple adjustments, the ApoE epsilon4 allele was significantly associated with apathy.

CONCLUSION

Our results suggest a relationship between the ApoE epsilon4 allele and apathy in patients with AD.

Oxidative stress in brain aging, neurodegenerative and vascular diseases: an overview

According to the free radical theory, aging can be considered as a progressive, inevitable process partially related to the accumulation of oxidative damage into biomolecules -- nucleic acids, lipids, proteins or carbohydrates -- due to an imbalance between prooxidants and antioxidants in favor of the former. More recently also the pathogenesis of several diseases has been linked to a condition of oxidative stress. In this review we focus our attention on the evidence of oxidative stress in aging brain, some of the most important neurodegenerative diseases -- Alzheimer's disease (AD), mild cognitive impairment (MCI), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD) -- and in two common and highly disabling vascular pathologies--stroke and cardiac failure. Particular attention will be given to the current knowledge about the biomarkers of oxidative stress that can be possibly used to monitor their severity and outcome.

Incidence and etiology of dementia in a large elderly Italian population

OBJECTIVE

To estimate age- and sex-specific incidence of dementia, Alzheimer disease (AD), and vascular dementia (VaD) in the Conselice Study of Brain Aging, an Italian prospective population-based study, and to assess whether poor education is a risk factor for dementia.

METHODS

In 1999 to 2000, the baseline study identified a dementia-free cohort of 937 subjects aged 65 years and older who were reexamined in 2003 to 2004 using a two-phase procedure.

RESULTS

Information was obtained for 91% of the subjects at risk; 115 incident cases of dementia were identified. Incidence rates per 1,000 person-years were 37.8 (95% CI = 30.0 to 47.7) for dementia, 23.8 (95% CI = 17.3 to 31.7) for AD, and 11.0 (95% CI = 7.2 to 16.9) for VaD. This translates into more than 400,000 new cases of dementia expected per year in Italy. Increasing age was an independent risk factor for both AD and VaD. Poor education was an independent risk factor for AD but not VaD. Sex did not affect dementia risk.

CONCLUSIONS

In this Italian population-based cohort, incidence of dementia increased with age, and Alzheimer disease (AD) was the most frequent type of dementia. Poor education was associated with a higher risk of AD. Our incidence rates are higher than previously reported in Italy, and provide new estimates for projection of future burden of disease in Italy.

Peripheral blood markers of inflammation and functional impairment in elderly community-dwellers

The cross-sectional association of functional impairment with several peripheral blood inflammatory markers (increased C-reactive protein (CRP), fibrinogen and leucocyte count, decreased cholesterol and albumin) was studied in 739 elderly community-dwellers. Functional measures included Tinetti test for gait and balance, and basic and Instrumental Activities of Daily Living. When considering each marker individually, only increased CRP was inversely associated with all functional measures independently of demographics, lifestyle, and comorbidity (P < 0.05). When considering the sum of positive markers, having more than one marker was also inversely associated with all functional measures (P < 0.05), but no clear gradient of impairment was found across increasing numbers of markers. When considering specific combinations of markers, having both increased CRP and at least another positive marker had a stronger association with functional impairment (P < 0.01 for all measures) than increased CRP alone (P > 0.05), or other positive markers alone or in combination (P < 0.05). In conclusion, in elderly individuals, peripheral blood markers of inflammation are associated with functional impairment independently of potential confounders. A specific combination of CRP with other markers provides a better correlate of functional impairment than both individual markers or a simple count of positive markers.

Antioxidants for the treatment of mild cognitive impairment

The isolated deficit in recent memory frequently associated with decline to Alzheimer's disease (AD) is defined as mild cognitive impairment (MCI). The observed progression of MCI to AD suggests a common pathogenesis between these two clinical syndromes, and several neuroimaging, neuropsychological and biological methods are applied with the purpose of identifying subjects at risk of AD. Among these methods, the evaluation of a condition of oxidative stress is gaining increasing attention. Since oxidative stress seems to be involved in the earliest phases of AD, and MCI may be considered as a prodromal phase of dementia, it is an attractive issue to focus therapeutic interventions on the early phase of the disease.

Plasma homocysteine and inflammation in elderly patients with cardiovascular disease and dementia

Increased levels of plasma total homocysteine (tHcy) may play a role in both cardiovascular diseases (CVD) and old-age dementias via enhancement of vascular inflammation. However, the association between plasma tHcy and serum C-reactive protein (sCRP), taken as a marker of low-grade inflammation, is still uncertain. We investigated this association in normal aging, CVD, and dementia, and examined whether it was modified by the presence of two major comorbid diseases of older age: chronic obstructive pulmonary disease (CPOD) and peptic ulcer (PU). Six hundred-twenty-seven individuals aged > or = 65 yr (74+/-7 yr) were selected for this study: 373 healthy controls; 160 patients with CVD but no evidence of comorbid diseases (CVD+/comorbidity-); 46 patients with CVD and concurrent CPOD and/or PU (CVD+/comorbidity+); and 48 patients with dementia. A positive association between plasma tHcy and serum CRP, independent of several confounders (socio-demographic status, known tHcy and sCRP determinants, inflammation markers, traditional vascular risk factors), was found for CVD+/comorbidity+ (p=0.001; not affected by dementia type) and dementia (p=0.001; not affected by dementia type), but not for CVD+/comorbidity- and controls. The results suggest that the association between plasma tHcy and sCRP is more an aspecific reflection of poor health than a specific correlate of vascular inflammation.

Direct measurement of the g factor of composite fermions

The activation gap Delta of the fractional quantum Hall states at constant fillings nu=2/3 and 2/5 has been measured as a function of the perpendicular magnetic field B. A linear dependence of Delta on B is observed while approaching the spin-polarization transition. This feature allows a direct measurement of the g factor of composite fermions which appears to be heavily renormalized by interactions and strongly sensitive to the electronic filling factor.

The clock-drawing test in elderly Italian community dwellers: associations with sociodemographic status and risk factors for vascular cognitive impairment

To evaluate whether performance in the clock-drawing test (CDT) is associated with sociodemographic status and risk factors for cognitive impairment, we examined 744 Italian community dwellers aged > or =65 (73 +/- 6) years scoring > or =24 on the MMSE. CDT was scored by two different methods, the Sunderland and the Wolf-Klein methods. Sociodemographic, lifestyle, clinical and biochemical variables were also recorded. For both scoring methods, lower CDT scores were associated with age, poor education, increased serum C-reactive protein and history of cancer. Associations of lower CDT scores with increased serum glucose and history of cerebrovascular disease were also found for the method with the highest sensitivity to cognitive impairment. This study shows that in elderly community dwellers, CDT may be not totally free from sociodemographic biases, and that it is associated with risk factors for cognitive impairment and frailty.

Muscle activation pattern and gait biomechanics after total knee replacement

OBJECTIVE

The aim of this study is to evaluate residual muscle function abnormalities after total knee replacement, with respect to gait kinematics and kinetics.

DESIGN

Longitudinal study on a follow-up of up to two years.

BACKGROUND

Gait usually presents an excellent improvement after total knee replacement. Nevertheless, some kinematics and kinetics abnormalities persist even after a long period of time and they might have implications in long-term prosthesis failure. Additionally, lower limb muscle activity has not been sufficiently studied in the past directly by means of dynamic EMG.

METHODS

Nine patients who had a posterior cruciate sparing total knee replacement design were evaluated by means of clinical assessment and gait analysis at the end of rehabilitation trials at six, twelve and twenty four months. EMG from trunk and lower limb muscles was registered and elaborated through a statistical detector for the on-off timing.

RESULTS

Gait analysis showed a slow gait, with a "stiff knee gait pattern" and prolonged muscular co-contractions during stance.

CONCLUSIONS

Knee kinematics and kinetics abnormalities during loading acceptance after total knee replacement are associated with co-contractions in muscular activation pattern.

RELEVANCE

Gait pattern at two years after total knee replacement is deemed unphysiological, potentially dangerous for the implant duration in time and responsible for residual disability in patients. Muscular behavior during daily activities provides insight into the integration of the prosthetic biomechanics within the muscular-skeletal system. This information is of relevance to improve prosthetic design, rehabilitation programs and knee motor performance.

Plasma antioxidants are similarly depleted in mild cognitive impairment and in Alzheimer's disease

In order to assess peripheral levels and activities of a broad spectrum of non-enzymatic and enzymatic antioxidants in elderly subjects with mild cognitive impairment (MCI) and Alzheimer's disease (AD), plasma levels of water-soluble (Vitamin C and uric acid) and of lipophilic (Vitamin A, Vitamin E and carotenoids including lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha- and beta-carotene) antioxidant micronutrients as well as activities of plasma and red blood cell (RBC) superoxide dismutase (SOD) and of plasma glutathione peroxidase (GPx) were measured in 25 patients with MCI, 63 AD patients and 53 controls. Peripheral levels and activities of antioxidants were similarly lower in MCI and AD patients as compared to controls. As MCI may represent a prodromal stage of AD, and oxidative damage appears to occur as one of the earliest pathophysiological events in AD, an increased intake of antioxidants in patients with MCI could be helpful in lowering the risk of conversion to dementia.

Comparative results between two groups of track-and-field athletes with or without the use of Master Amino acid Pattern as protein substitute

Comparative results of this study have shown that athletes, by taking the Master Amino acid Pattern (MAP) as a dietary protein substitute and performing physical activity, have had (1) increased body muscle mass, strength, and endurance; (2) decreased fat mass; (3) increased basal metabolism rate; (4) greater improvement in performance of the nonprevailing muscles compared to the prevailing ones; and (5) improved muscular and hematologic lactate clearance, which allows for better muscle performance and faster muscle recovery after physical activity. It was concluded that the use of MAP as a dietary protein substitute in conjunction with physical activity can provide a safe and unprecedented way to optimize the body's protein synthesis, thereby improving anthropometric characteristics and physical and physiologic performance.