Evelyn Ferri

Peripheral blood mononuclear cells as a laboratory to study dementia in the elderly

The steady and dramatic increase in the incidence of Alzheimers disease (AD) and the lack of effective treatments have stimulated the search for strategies to prevent or delay its onset and/or progression. Since the diagnosis of dementia requires a number of established features that are present when the disease is fully developed, but not always in the early stages, the need for a biological marker has proven to be urgent, in terms of both diagnosis and monitoring of AD. AD has been shown to affect peripheral blood mononuclear cells (PBMCs) that are a critical component of the immune system which provide defence against infection. Although studies are continuously supplying additional data that emphasize the central role of inflammation in AD, PBMCs have not been sufficiently investigated in this context. Delineating biochemical alterations in AD blood constituents may prove valuable in identifying accessible footprints that reflect degenerative processes within the Central Nervous System (CNS). In this review, we address the role of biomarkers in AD with a focus on the notion that PBMCs may serve as a peripheral laboratory to find molecular signatures that could aid in differential diagnosis with other forms of dementia and in monitoring of disease progression.

Different Adenosine A2A Receptor Expression in Peripheral Cells from Elderly Patients with Vascular Dementia and Alzheimer's Disease

The line between vascular dementia (VaD) and Alzheimers disease (AD) is often blurred. In this study we investigated whether adenosine A2A receptor (A2AR) expression can be used to differentiate between VaD and AD. We evaluated the expression of this receptor in the peripheral blood mononuclear cells of patients with VaD, mild cognitive impairment, AD, and controls. We found statistically significant lower levels of A2AR mRNA in VaD compared to AD subjects. These data suggest that A2AR expression may help in the differential diagnosis between VaD and AD.

GRN Thr272fs clinical heterogeneity: a case with atypical late onset presenting with a dementia with Lewy bodies phenotype.

We describe a case of late onset frontotemporal dementia carrying the g.1977_1980 delCACT (Thr272fs) mutation in progranulin (GRN) gene, characterized by a positive family history for dementia and a clinical phenotype resembling dementia with Lewy bodies. Symptoms included prominent visuospatial impairment, complex misidentification syndrome, visual zooptic hallucinations, hypersomnia, mental fluctuations, and signs of parkinsonism. The patient showed normal cerebrospinal fluid levels of amyloid-β, tau, and Ptau biomarkers, an asymmetric pattern of cerebral atrophy and hypoperfusion, and parietal hypometabolism. A major contributing factor to the diagnosis was the testing of plasmatic progranulin levels (extremely low), which prompted us to sequence GRN.

Gene promoter methylation and expression of Pin1 differ between patients with frontotemporal dementia and Alzheimer's disease

Frontotemporal Dementia (FTD) and Alzheimers Disease (AD) share the accumulation of fibrillar aggregates of misfolded proteins. To better understand these neurodegenerative diseases and identify biomarkers in easily accessible cells, we investigated DNA methylation at Pin1 gene promoter and its expression in peripheral blood mononuclear cells of FTD patients. We found a lower gene expression of Pin1 with a higher DNA methylation in three CpG sites at Pin1 gene promoter analysed in FTD subjects, in contrast to a higher gene expression with a lower methylation in AD subjects and controls. These data suggest an important and distinct involvement of Pin1 in these two types of dementia.

Leukocyte Telomere Length in Alzheimer’s Disease Patients with a Different Rate of Progression

BACKGROUND Age and short leukocyte telomeres have been associated with a higher risk of Alzheimers disease (AD). Inflammation is involved in AD and it is suggested that anti-inflammatory interleukin-10 (IL-10) may partly antagonize these processes. OBJECTIVE The aim is to correlate telomere length (TL) in peripheral blood mononuclear cells (PBMC) from patients with AD to disease progression rate. Moreover, we evaluated whether TL was associated with IL-10 production by unstimulated or amyloid-β (Aβ)-stimulated PBMC. METHODS We enrolled 31 late-onset AD and 20 age-matched healthy elderly (HE). After a two-year follow-up period, patients were retrospectively evaluated as slow-progressing (ADS) (Mini Mental State Examination (MMSE) decline over the two years of follow-up ≤3 points) or fast progressing AD (ADF) (MMSE decline ≥5 points). TL was measured by flow cytometry and in vitro IL-10 production by enzyme-linked immunosorbent assay. RESULTS TL (mean±SD) for HE, ADS, and ADF was 2.3±0.1, 2.0±0.1, and 2.5±0.1 Kb, respectively. ADS showed a shorter TL compared to HE (p = 0.034) and to ADF (p = 0.005). MMSE decline correlated with TL in AD (R2 = 0.284; p = 0.008). We found a significant difference in IL-10 production between unstimulated and Aβ-stimulated PBMC from ADS (40.7±13.7 versus 59.0±27.0; p = 0.004) but not from ADF (39.7±14.4 versus 42.2±22.4). HE showed a trend toward significance (47.1±25.4 versus 55.3±27.9; p = 0.10). CONCLUSION PBMC from ADF may be characterized by an impaired response induced by Aβ and by a reduced proliferative response responsible for the longer telomeres. TL might be a contributing factor in predicting the rate of AD progression.

Interleukin-10 Production in Response to Amyloid-β Differs between Slow and Fast Decliners in Patients with Alzheimer’s Disease

We investigated IL-10 and IL-6 production in amyloid-β (Aβ) stimulated peripheral blood mononuclear cells (PBMCs) in twenty Alzheimers disease (AD) patients with slow progression, eleven with fast progression, and twenty age-matched controls. Promoter polymorphisms in IL-10 (position -592, -819, -1082), IL-6 (-174), transforming growth factor-β1 (TGF-β1) (-10, -25), interferon-γ (IFN-γ) (-874), and tumor necrosis factor-α (TNF-α) (-308) genes were analyzed. IL-10 production after Aβ stimulation was high in PBMCs from slow decliners and almost completely abrogated in fast decliners. Association between AA IFN-γ low-producing genotype and fast progression was demonstrated. Investigations in a larger sample will clarify these findings.

Protein signature in cerebrospinal fluid and serum of Alzheimer’s disease patients: The case of apolipoprotein A-1 proteoforms

In the diagnosis of Alzheimer’s disease (AD) total tau (T-tau), tau phosphorylated at threonine 181 (P-tau181), and the 42 amino acid isoform of alpha β-amyloid (Aβ) are well established surrogate CSF markers. However, there is a constant need for new diagnostic markers to identify the disease at a very early stage. The identification of new molecules for AD diagnosis and monitoring in CSF is hampered by several “confounding” factors including intra- and inter-individual, pre-analytical and analytical variabilities. In an attempt to partially overcome patient’s variability and to determine new molecules significantly dysregulated in CSF, we assessed the proteome profile of low molecular weight protein species in CSF and serum of the same patients. CSFs and sera from 36 ADs, 32 iNPHs (idiopathic normal pressure hydrocephalus) and 12 controls were compared by MALDI profiling (non-parametric statistics, CV<20%, AUC>0.750). After protein identification by mass spectrometry, the proteoform composition was assessed by 2-D DIGE/MS. Results indicated that CSF of iNPH can be used as control. Serum and CSF of AD patients shows a specific protein profile compared to iNPH samples. A variation (p<0.01) of Apo A-1 levels in AD, together with a specific dysregulation of Apo A-1 proteoforms was observed. The profiling of CSF and serum of the same patients, suggests that the decrement of total Apo A-1 occurs specifically in CSF. Serum and CSF of AD shows a characteristic Apo A-1 proteoform pattern suggesting it as potential marker which can support the clinical workflow adopted for AD diagnosis and progression.

Down-regulation of adenosine A1 and A2A receptors in peripheral cells from idiopathic normal-pressure hydrocephalus patients

Idiopathic normal-pressure hydrocephalus (iNPH) is a neurological disease that usually develops in the elderly. Natural history of iNPH is still unknown. It has been hypothesized that cerebrovascular diseases could have a role in etiology of chronic hydrocephalus and studies show an increased prevalence of cardiovascular diseases in iNPH patients. Moreover, evidences show a possible alteration of immune system in iNPH patients. Adenosine (Ado) is a metabolite produced in response to metabolic stress and injury. Adenosine and its receptors play an important role in vascular protection and in the modulation of inflammatory reactions and neuroinflammation. Our aim is to evaluate gene and protein expression of A1R and A2AR in the peripheral blood mononuclear cells (PBMCs) from iNPH patients compared to control subjects. We investigate if Ado system, that plays an important role in central nervous system, in vascular system, and also in inflammation, is involved in pathophysiology of iNPH disease. Our analysis showed that A1R mRNA levels and A1R density in PBMCs from iNPH patients were significantly lower than CT subjects (0.84 ± 0.12 and 2.42 ± 0.42, p<0.001 and 0.31 ± 0.02 and 0.42 ± 0.04, p=0.043; respectively). About A2AR, the gene expression in PBMCs was significantly lower in iNPH than CT (0.65 ± 0.09 and 1.5 ± 0.14, p<0.001) as well as there was a trend in protein expression: iNPH and CT (0.51 ± 0.05 and 0.62 ± 0.03; p=0.172). This preliminary study underlines the involvement of Ado system in iNPH disease whose pathophysiology is still unclear.

Phenotypic Variability associated with the C9ORF72 Hexanucleotide Repeat Expansion: A Sporadic Case of Frontotemporal Lobar Degeneration with Prodromal Hyposmia and Predominant Semantic Deficits

We describe a sporadic case of frontotemporal lobar degeneration, associated with the C9ORF72 mutation, with prominent behavioral changes and semantic deficits. Predominant deficits in naming, vocabulary, word comprehension, and face and object recognition emerged on neuropsychological assessment. Amnesia, behavioral changes, and isolated psychotic symptoms were also present. Hyposmia was an unspecific prodromal sign. Brain imaging showed basofrontal and temporopolar hypometabolism bilaterally, and predominantly left-sided atrophy. Levels of cerebrospinal fluid biomarkers (amyloid-β, tau and p-tau) were normal. This description further confirms the heterogeneous presentation of the C9ORF72 mutation.

Heterogeneity of Thyroid Function and Impact of Peripheral Thyroxine Deiodination in Centenarians and Semi-Supercentenarians: Association With Functional Status and Mortality

Thyroid hormones (FT3, FT4) and thyroid-stimulating hormone (TSH) were evaluated in a population of 672 well-characterized Italian subjects (age range: 52-113 years), including an unprecedented number of centenarians, semi-supercentenarians, as well as centenarians offspring and age-matched elderly (CENT, 105+, CENTOFF, and CTRL, respectively). The results show that FT3 level and FT3/FT4 ratio decrease while FT4 and TSH increase in an age-dependent manner. In CENT/105+, higher FT4 level, and lower FT3/FT4 ratio are associated with an impaired functional status and an increased mortality. A cluster analysis identified three clusters of CENT/105+ based on their FT3, FT4, and TSH levels. Cluster 3, characterized by lower FT3 and TSH and higher FT4, shows the worst health status and the shortest survival. Thus, the age-related changes of thyroid hormones extend to the most advanced age, and CENT/105+ are highly heterogeneous regarding thyroid function. This heterogeneity is related to different health, functional and cognitive status, as well as with survival/mortality in CENT/105+. Finally, we investigated a remarkable number of CENT/105+ showing a thyroid profile suggestive of non-thyroidal illness syndrome (NTIS) (excluded from the previous analysis). NTIS CENT/105+ are characterized by a worse functional and cognitive status and an increased mortality with respect to CENT/105+ without NTIS.