In JoVE (1)

Other Publications (16)

Articles by Diego Iacono in JoVE

Other articles by Diego Iacono on PubMed

Donepezil Versus Vitamin E in Alzheimer's Disease: Part 2: Mild Versus Moderate-severe Alzheimer's Disease

Clinical Neuropharmacology. Jul-Aug, 2002  |  Pubmed ID: 12151908

Early studies showed that the latency of P300 (P3) event related potential increases or diminishes when anticholinergic or cholinergic drugs are administered. We tested the hypothesis that new cholinesterase inhibitors like Donepezil (DPZ) may have an effect on the often abnormal P300 of patients with Alzheimer's Disease (AD), and therefore, that P300 recordings might simplify the evaluation of responses to cholinesterase inhibitor in patients with mild and moderate-severe AD. We evaluated 60 patients with AD: 30 patients with "mild" (Mini Mental State Examination 26-19) and 30 patients with "moderate-severe" (Mini Mental State Examination 18-10), according to the National Institute of Neurological and Communicative Disorders and Alzheimer's Disease and Related Disorders Association criteria in comparison with 40 age-matched controls. All subjects underwent P300 recordings and neuropsychologic examinations (Alzheimer's Disease Assessment Scale-Cognition and Wechsler Adult Intelligence Scale) during the 6-month follow-up. Patients were divided into four groups of 15 patients each: Group I DPZ (10 mg/day) and Group I Vitamin E (2000 IU/day) with "mild" AD; Group II DPZ and Group II Vitamin E with "moderate-severe" AD and same drug dosages. In patients treated with Vitamin E, we observed P3 latency increments (delta) by 11.8 +/- 1.8 ms in Group I and by 12.8 +/- 2.8 ms in Group II at 6 months; neuropsychologic test scores significantly worsened at 6 months (p < 0.001) in Group II patients. Donepezil induced significant P3 latency reductions (11.2 +/- 2.4 ms) in nine patients of Group I and all patients of Group II (16.1 +/- 4.0 ms), reaching a maximum at 3 months (23.2 +/- 2.7 ms). Alzheimer's Disease Assessment Scale-Cognition and Wechsler Adult Intelligence Scale scores improved during the same period, and the difference between Vitamin E and DPZ treated patients was highly significant for P3 (analysis of variance) and for P3-Alzheimer's Diseases Assessment Scale-Cognition (analysis of covariance) with p < 0.001 for pooled groups of patients with AD and Group II (DPZ) versus Group II (Vitamin E). Combined P3 event related potentials measurements, neuropsychologic test comparison evidences significant effects of DPZ in mild and in moderate-severe AD.

HLA Typing Does Not Predict REM Sleep Behaviour Disorder and Hallucinations in Parkinson's Disease

Movement Disorders : Official Journal of the Movement Disorder Society. Mar, 2003  |  Pubmed ID: 12621640

HLA-DR2 haplotype and DQ1 DNA alleles, characterizing 90 to 100% of all narcoleptic patients, were found to be equally distributed in 20 Parkinson's disease (PD) patients with early hallucinations, rapid eye movement (REM) sleep-related behaviour disturbances (RBD), and sleep onset in REM (SOREM), and in 20 PD patients without hallucinations, despite 10 to 15 years of treatment, and no RBD or SOREM.

The Effects of a Cholinesterase Inhibitor Are Prominent in Patients with Fluctuating Cognition: a Part 3 Study of the Main Mechanism of Cholinesterase Inhibitors in Dementia

Clinical Neuropharmacology. Sep-Oct, 2003  |  Pubmed ID: 14520164

Fluctuating cognition is evidenced in different forms of dementia and is accompanied by electroencephalographic (EEG) abnormalities. The authors hypothesize that cholinesterase inhibitors are effective mostly in patients with fluctuating cognition. Twenty-three patients affected by mild dementia with similar scores on Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale-cognitive subscale (ADAS-cog), and Unified Parkinson's Disease Rating Scale evaluation were classified in a group with fluctuating cognition (n = 11) and a group of nonfluctuators (n = 12). All patients were assigned randomly to the branches of a double-blind crossover study of donepezil (DPZ), a 5 to 10-mg dose, versus vitamin E, a 2000 IU dose, for 30 days. MMSE, ADAS-cog, University of California at Los Angeles Neuropsychiatric Inventory (NPI), quantitative EEG, P3 event-related potentials, choice reaction time variability (CRTV) were assessed at baseline and at the end of treatments. At the end of the crossover study all patients received DPZ for 6 months. The dominant EEG frequency variability, low EEG frequencies amplitude, the P3 latency and jitter, CRTV, and NPI was significantly different in the fluctuating cognition group than the nonfluctuating group at baseline (P < 0.001). Short-term DPZ administration induced a significant increase in MMSE scores, reduction of ADAS-cog and of NPI scores (P < 0.003-0.001), increase of EEG alpha activity and reductions of P3 latency and jitter, dominant frequency variability and CRTV (P < 0.009-0.001) in the fluctuating cognition group, and significant increases of MMSE scores (P = 0.03) and a decrease of P3 jitter and dominant frequency variability (P < 0.034-0.041) in the nonfluctuating group. Short-term DPZ effects differed significantly between fluctuating cognition and nonfluctuating patients (0.001). Significant effects of the 6-month observation were observed only in fluctuating cognition patients. Logistic analysis showed that P3 latency predicts the effect of DPZ (P = 0.04, P < 0.01) in the crossover study, and CRTV predicts the effect at the 6-month follow-up.

Resistance to Alzheimer's Pathology is Associated with Nuclear Hypertrophy in Neurons

Neurobiology of Aging. Oct, 2007  |  Pubmed ID: 17599696

This study focuses on the morphometric changes of neurons in asymptomatic Alzheimer's disease (AD), a state characterized by the presence of AD lesions in subjects without cognitive impairment. In autopsy brains, we used stereological methods to compare the cell body and nuclear volumes of anterior cingulate gyrus (ACG) and CA1 hippocampal neurons in asymptomatic AD subjects (n=9), subjects with AD dementia (AD, n=8), mild cognitive impairment (MCI, n=9), and age-matched controls (controls, n=9). In ACG, we observed a significant decrease in the neuronal volume of MCI and AD compared to controls; by contrast, no atrophy was present in asymptomatic AD. Moreover, we found a significant increase in nuclear volume in asymptomatic AD compared to controls (P<0.001), MCI (P<0.01) and AD (P<0.001) brains. Similar results were found in the CA1 region of the hippocampus. This nuclear hypertrophy may represent an early neuronal reaction to Abeta or Tau, or a compensatory mechanism which forestalls the progression of AD and allows the brain to resist the development of dementia.

Neuronal Hypertrophy in Asymptomatic Alzheimer Disease

Journal of Neuropathology and Experimental Neurology. Jun, 2008  |  Pubmed ID: 18520776

The pathologic changes of Alzheimer disease (AD) evolve very gradually over decades before the disease becomes clinically manifest. Thus, it is not uncommon to find substantial numbers of Abeta plaques and neurofibrillary tangles in autopsy brains of older subjects with documented normal cognition, a state that we define as asymptomatic AD (ASYMAD). The goal of this study is to understand the morphometric substrate of ASYMAD subjects compared with mild cognitive impairment and definite AD cases. We used designed-based stereology to measure the volumes of neuronal cell bodies, nuclei, and nucleoli in 4 cerebral regions: anterior cingulate gyrus, posterior cingulate gyrus, primary visual cortex, and CA1 of hippocampus. We examined and compared autopsy brains from 4 groups (n = 15 each) of participants in the Baltimore Longitudinal Study of Aging: ASYMAD, mild cognitive impairment, AD, and age-matched controls. We found significant hypertrophy of the neuronal cell bodies, nuclei, and nucleoli of CA1 of hippocampus and anterior cingulate gyrus neurons in ASYMAD subjects compared with control and mild cognitive impairment cases. In the posterior cingulate gyrus and primary visual cortex, the hypertrophy was limited to the nuclei and nucleoli. The hypertrophy of cortical neurons and their nuclei and nucleoli in ASYMAD may represent an early reaction to the presence of neurotoxic Abeta or tau, or a compensatory mechanism that prevents the progression of the disease into dementia.

Neuropathologic Studies of the Baltimore Longitudinal Study of Aging (BLSA)

Journal of Alzheimer's Disease : JAD. 2009  |  Pubmed ID: 19661626

The Baltimore Longitudinal Study of Aging (BLSA) was established in 1958 and is one the oldest prospective studies of aging in the USA and the world. The BLSA is supported by the National Institute of Aging (NIA) and its mission is to learn what happens to people as they get old and how to sort out changes due to aging from those due to disease or other causes. In 1986, an autopsy program combined with comprehensive neurologic and cognitive evaluations was established in collaboration with the Johns Hopkins University Alzheimer's Disease Research Center (ADRC). Since then, 211 subjects have undergone autopsy. Here we review the key clinical neuropathological correlations from this autopsy series. The focus is on the morphological and biochemical changes that occur in normal aging, and the early neuropathological changes of neurodegenerative diseases, especially Alzheimer's disease (AD). We highlight the combined clinical, pathologic, morphometric, and biochemical evidence of asymptomatic AD, a state characterized by normal clinical evaluations in subjects with abundant AD pathology. We conclude that in some individuals, successful cognitive aging results from compensatory mechanisms that occur at the neuronal level (i.e., neuronal hypertrophy and synaptic plasticity) whereas a failure of compensation may culminate in disease.

In Vivo Fibrillar Beta-amyloid Detected Using [11C]PiB Positron Emission Tomography and Neuropathologic Assessment in Older Adults

Archives of Neurology. Feb, 2011  |  Pubmed ID: 21320990

In demented older adults, in vivo amyloid imaging shows agreement with diagnostic neuropathologic assessment of β-amyloid (Aβ). However, the extent of agreement in nondemented older adults remains unclear.

Personality and Resilience to Alzheimer's Disease Neuropathology: a Prospective Autopsy Study

Neurobiology of Aging. Apr, 2013  |  Pubmed ID: 23040035

Alzheimer's disease (AD) neuropathology is found at autopsy in approximately 30% of cognitively normal older individuals. We examined whether personality traits are associated with such resilience to clinical dementia in individuals with AD neuropathology. Broad factors and specific facets of personality were assessed up to 28 years (mean 11 ± 7 years) before onset of dementia and up to 30 years (mean 15 ± 7 years) before death in a cohort (n = 111) evaluated for AD neuropathology at autopsy. Individuals with higher baseline scores on vulnerability to stress, anxiety, and depression (neuroticism: odds ratio, 2.0; 95% confidence interval, 1.2-3.5), or lower scores on order and competence (conscientiousness: odds ratio, 0.4; 95% confidence interval, 0.2-0.9) were less likely to remain asymptomatic in the presence of AD neuropathology. Neuroticism (r = 0.26), low agreeableness (r = -0.34), and some facets were also significantly associated with advanced stages of neurofibrillary tangles, but the associations between personality traits and risk of clinical dementia were mostly unchanged by controlling for the extent of neurofibrillary tangles and Aβ neuritic plaques. In sum, a resilient personality profile is associated with lower risk or delay of clinical dementia even in persons with AD neuropathology.

Neuropathologic Assessment of Dementia Markers in Identical and Fraternal Twins

Brain Pathology (Zurich, Switzerland). Jul, 2014  |  Pubmed ID: 24450926

Twin studies are an incomparable source of investigation to shed light on genetic and non-genetic components of neurodegenerative diseases, as Alzheimer's disease (AD). Detailed clinicopathologic correlations using twin longitudinal data and post-mortem examinations are mostly missing. We describe clinical and pathologic findings of seven monozygotic (MZ) and dizygotic (DZ) twin pairs. Our findings show good agreement between clinical and pathologic diagnoses in the majority of the twin pairs, with greater neuropathologic concordance in MZ than DZ twins. Greater neuropathologic concordance was found for β-amyloid than tau pathology within the pairs. ApoE4 was associated with higher β-amyloid and earlier dementia onset, and importantly, higher frequency of other co-occurring brain pathologies, regardless of the zygosity. Dementia onset, dementia duration, difference between twins in age at dementia onset and at death, did not correlate with AD pathology. These clinicopathologic correlations of older identical and fraternal twins support the relevance of genetic factors in AD, but not their sufficiency to determine the pathology, and consequently the disease, even in monozygotic twins. It is the interaction among genetic and non-genetic risks which plays a major role in influencing, or probably determining, the degeneration of those brain circuits associated with pathology and cognitive deficits in AD.

Mild Cognitive Impairment and Asymptomatic Alzheimer Disease Subjects: Equivalent β-amyloid and Tau Loads with Divergent Cognitive Outcomes

Journal of Neuropathology and Experimental Neurology. Apr, 2014  |  Pubmed ID: 24607960

Older adults with intact cognition before death and substantial Alzheimer disease (AD) lesions at autopsy have been termed "asymptomatic AD subjects" (ASYMAD). We previously reported hypertrophy of neuronal cell bodies, nuclei, and nucleoli in the CA1 of the hippocampus (CA1), anterior cingulate gyrus, posterior cingulate gyrus, and primary visual cortex of ASYMAD versus age-matched Control and mild cognitive impairment (MCI) subjects. However, it was unclear whether the neuronal hypertrophy could be attributed to differences in the severity of AD pathology. Here, we performed quantitative analyses of the severity of β-amyloid (Aβ) and phosphorylated tau (tau) loads in the brains of ASYMAD, Control, MCI, and AD subjects (n = 15 per group) from the Baltimore Longitudinal Study of Aging. Tissue sections from CA1, anterior cingulate gyrus, posterior cingulate gyrus, and primary visual cortex were immunostained for Aβ and tau; the respective loads were assessed using unbiased stereology by measuring the fractional areas of immunoreactivity for each protein in each region. The ASYMAD and MCI groups did not differ in Aβ and tau loads. These data confirm that ASYMAD and MCI subjects have comparable loads of insoluble Aβ and tau in regions vulnerable to AD pathology despite divergent cognitive outcomes. These findings imply that cognitive impairment in AD may be caused or modulated by factors other than insoluble forms of Aβ and tau.

Reduced Number of Pigmented Neurons in the Substantia Nigra of Dystonia Patients? Findings from Extensive Neuropathologic, Immunohistochemistry, and Quantitative Analyses

Tremor and Other Hyperkinetic Movements (New York, N.Y.). 2015  |  Pubmed ID: 26069855

Dystonias (Dys) represent the third most common movement disorder after essential tremor (ET) and Parkinson's disease (PD). While some pathogenetic mechanisms and genetic causes of Dys have been identified, little is known about their neuropathologic features. Previous neuropathologic studies have reported generically defined neuronal loss in various cerebral regions of Dys brains, mostly in the basal ganglia (BG), and specifically in the substantia nigra (SN). Enlarged pigmented neurons in the SN of Dys patients with and without specific genetic mutations (e.g., GAG deletions in DYT1 dystonia) have also been described. Whether or not Dys brains are associated with decreased numbers or other morphometric changes of specific neuronal types is unknown and has never been addressed with quantitative methodologies.

APOε2 and Education in Cognitively Normal Older Subjects with High Levels of AD Pathology at Autopsy: Findings from the Nun Study

Oncotarget. Jun, 2015  |  Pubmed ID: 26101858

Asymptomatic Alzheimer's disease (ASYMAD) subjects are individuals characterized by preserved cognition before death despite substantial AD pathology at autopsy. ASYMAD subjects show comparable levels of AD pathology, i.e. β-amyloid neuritic plaques (Aβ-NP) and tau-neurofibrillary tangles (NFT), to those observed in mild cognitive impairment (MCI) and some definite AD cases. Previous clinicopathologic studies on ASYMAD subjects have shown specific phenomena of hypertrophy in the cell bodies, nuclei, and nucleoli of hippocampal pyramidal neurons and other cerebral areas. Since it is well established that the allele APOε4 is a major genetic risk factor for AD, we examined whether specific alleles of APOE could be associated with the different clinical outcomes between ASYMAD and MCI subjects despite equivalent AD pathology. A total of 523 brains from the Nun Study were screened for this investigation. The results showed higher APOε2 frequency (p < 0.001) in ASYMAD (19.2%) vs. MCI (0%) and vs. AD (4.7%). Furthermore, higher education in ASYMAD vs. MCI and AD (p < 0.05) was found. These novel autopsy-verified findings support the hypothesis of the beneficial effect of APOε2 and education, both which seem to act as contributing factors in delaying or forestalling the clinical manifestations of AD despite consistent levels of AD pathology.

Sporadic Creutzfeldt-Jakob Disease: Prion Pathology in Medulla Oblongata-Possible Routes of Infection and Host Susceptibility

BioMed Research International. 2015  |  Pubmed ID: 26457299

Sporadic Creutzfeldt-Jakob disease (sCJD), the most frequent human prion disorder, is characterized by remarkable phenotypic variability, which is influenced by the conformation of the pathologic prion protein and the methionine/valine polymorphic codon 129 of the prion protein gene. While the etiology of sCJD remains unknown, it has been hypothesized that environmental exposure to prions might occur through conjunctival/mucosal contact, oral ingestion, inhalation, or simultaneous involvement of the olfactory and enteric systems. We studied 21 subjects with definite sCJD to assess neuropathological involvement of the dorsal motor nucleus of the vagus and other medullary nuclei and to evaluate possible associations with codon 129 genotype and prion protein conformation. The present data show that prion protein deposition was detected in medullary nuclei of distinct sCJD subtypes, either valine homozygous or heterozygous at codon 129. These findings suggest that an "environmental exposure" might occur, supporting the hypothesis that external sources of contamination could contribute to sCJD in susceptible hosts. Furthermore, these novel data could shed the light on possible causes of sCJD through a "triple match" hypothesis that identify environmental exposure, host genotype, and direct exposure of specific anatomical regions as possible pathogenetic factors.

Parkinson Disease and Incidental Lewy Body Disease: Just a Question of Time?

Neurology. Nov, 2015  |  Pubmed ID: 26468408

To quantify the loss of pigmented neurons in the substantia nigra (SN) of autopsy-confirmed Parkinson disease (PD) and incidental Lewy body disease (ILBD) vs age-matched controls (C).

Same Ages, Same Genes: Same Brains, Same Pathologies?: Dementia Timings, Co-Occurring Brain Pathologies, ApoE Genotypes in Identical and Fraternal Age-matched Twins at Autopsy

Alzheimer Disease and Associated Disorders. Apr-Jun, 2016  |  Pubmed ID: 26492328

Localized Cortical Chronic Traumatic Encephalopathy Pathology After Single, Severe Axonal Injury in Human Brain

Acta Neuropathologica. Nov, 2016  |  Pubmed ID: 27885490

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with repetitive mild impact traumatic brain injury from contact sports. Recently, a consensus panel defined the pathognomonic lesion for CTE as accumulations of abnormally hyperphosphorylated tau (p-tau) in neurons (neurofibrillary tangles), astrocytes and cell processes distributed around small blood vessels at sulcal depths in irregular patterns within the cortex. The pathophysiological mechanism for this lesion is unknown. Moreover, a subset of CTE cases harbors cortical β-amyloid plaques. In this study, we analyzed postmortem brain tissues from five institutionalized patients with schizophrenia and history of surgical leucotomy with subsequent survival of at least another 40 years. Because leucotomy involves severing axons bilaterally in prefrontal cortex, this surgical procedure represents a human model of single traumatic brain injury with severe axonal damage and no external impact. We examined cortical tissues at the leucotomy site and at both prefrontal cortex rostral and frontal cortex caudal to the leucotomy site. For comparison, we analyzed brain tissues at equivalent neuroanatomical sites from non-leucotomized patients with schizophrenia, matched in age and gender. All five leucotomy cases revealed severe white matter damage with dense astrogliosis at the axotomy site and also neurofibrillary tangles and p-tau immunoreactive neurites in the overlying gray matter. Four cases displayed p-tau immunoreactivity in neurons, astrocytes and cell processes encompassing blood vessels at cortical sulcal depths in irregular patterns, similar to CTE. The three cases with apolipoprotein E ε4 haplotype showed scattered β-amyloid plaques in the overlying gray matter, but not the two cases with apolipoprotein E ε3/3 genotype. Brain tissue samples from prefrontal cortex rostral and frontal cortex caudal to the leucotomy site, and all cortical samples from the non-leucotomized patients, showed minimal p-tau and β-amyloid pathology. These findings suggest that chronic axonal damage contributes to the unique pathology of CTE over time.

simple hit counter