• Publikační typ
• časopisecké články MeSH

Dementia with Lewy bodies (DLB), Parkinson's disease (PD), and multiple system atrophy (MSA) are neurodegenerative disorders characterized by abnormal accumulation of α-synuclein. Plasmin is a serine protease with a role in various physiological processes, including tissue and synaptic remodeling, inflammation regulation, and modulation of neurotrophic factors. It has also been shown that plasmin is able to cleave extracellular α-synuclein in neuronal cell cultures. The plasminogen activator inhibitor-1 (PAI-1) and the tissue plasminogen activator (tPA) regulate the synthesis and activity of plasmin in the brain. We measured the serum levels of tPA and PAI-1 in 30 DLB, 10 PD, and 12 MSA patients and compared them to 10 adults (controls). tPA and PAI-1 serum protein concentrations were quantified by ELISA and compared across the groups. The findings demonstrated that PAI-1 serum levels were increased in DLB (p < 0.05), PD (p < 0.01), and MSA (p < 0.001) patients as compared to controls. In addition, MSA patients had higher PAI-1 serum levels (p < 0.01) as compared to DLB patients, showing the highest PAI-1 levels among all groups. No differences in tPA serum levels were found among groups. Our findings suggest an involvement of plasmin system in these synucleinopathies although there are some limitations due to the heterogeneity of our cohort of participants. Thus, these data must be seen as preliminary observations and further studies in larger and more homogenous cohorts are needed before drawing definitive conclusions.

• Publikační typ
• časopisecké články MeSH

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aβ) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aβ pathway, the plasmin system may affect cognition through synaptic activity.

• Klíčová slova
• dementia, frontotemporal lobar degeneration, plasminogen activator inhibitor‐1, tissue‐type plasminogen activator,
• MeSH
• biologické markery krev   MeSH
• frontotemporální lobární degenerace * krev   MeSH
• inhibitor aktivátoru plazminogenu 1 * krev   MeSH
• kognitivní dysfunkce krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• tkáňový aktivátor plazminogenu krev   metabolismus   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické markery MeSH
• inhibitor aktivátoru plazminogenu 1 * MeSH
• SERPINE1 protein, human MeSH Prohlížeč
• tkáňový aktivátor plazminogenu MeSH

We previously demonstrated that serum levels of plasminogen activator inhibitor-1 (PAI-1), which inhibits both the tissue plasminogen activator (tPA) and plasmin activity, are increased in patients with Alzheimer's disease. tPA/plasmin not only prevents the accumulation of β-amyloid in the brain but also is involved in the synthesis of the brain-derived neurotrophic factor (BDNF), a neurotrophin whose levels are reduced in Alzheimer. In the present study, we compared BDNF serum levels in Alzheimer patients with dementia to those in Alzheimer patients with amnestic mild cognitive impairment and to cognitively healthy controls. Moreover, we examined whether the PAI-1/BDNF ratio correlates with disease severity, as measured by Mini-Mental State Examination. Our results showed that BDNF serum levels are lower (13.7% less) and PAI-1 levels are higher in Alzheimer patients with dementia than in Alzheimer patients with amnestic mild cognitive impairment patients (23% more) or controls (36% more). Furthermore, the PAI-1/BDNF ratio was significantly increased in Alzheimer patients as compared to amnestic mild cognitive impairment (36.4% more) and controls (40% more). Lastly, the PAI-1/BDNF ratio negatively correlated with the Mini-Mental score. Our results suggest that increased PAI-1 levels in Alzheimer, by impairing the production of the BDNF, are implicated in disease progression. They also indicate that the PAI-1/BDNF ratio could be used as a marker of Alzheimer. In support of this hypothesis, a strong negative correlation between the PAI-1/BDNF ratio and the Mini-Mental score was observed.

• Publikační typ
• časopisecké články MeSH

Alzheimer's disease (AD) is a central nervous system (CNS) disease characterized by loss of memory, cognitive functions, and neurodegeneration. Plasmin is an enzyme degrading many plasma proteins. In the CNS, plasmin may reduce the accumulation of beta amyloid (Aβ) and have other actions relevant to AD pathophysiology. Brain plasmin synthesis is regulated by two enzymes: one activating, the tissue plasminogen activator (tPA), and the other inhibiting, the plasminogen activator inhibitor-1 (PAI-1). We investigated the levels of tPA and PAI-1 in serum from 40 AD and 40 amnestic mild cognitively impaired (aMCI) patients compared to 10 cognitively healthy controls. Moreover, we also examined the PAI-1/tPA ratio in these patient groups. Venous blood was collected and the PAI-1 and tPA serum concentrations were quantified using sandwich ELISAs. The results showed that PAI-1 levels increased in AD and aMCI patients. This increase negatively correlated with cognitive performance measured using the Mini-Mental Status Exam (MMSE). Similarly, the ratio between tPA and PAI-1 gradually increases in aMCI and AD patients. This study demonstrates that AD and aMCI patients have altered PAI-1 serum levels and PAI-1/tPA ratio. Since these enzymes are CNS regulators of plasmin, PAI-1 serum levels could be a marker reflecting cognitive decline in AD.

• Klíčová slova
• Alzheimer’s disease, amnestic mild cognitive impairment, plasmin, plasminogen activator inhibitor-1, ratio, tissue-type plasminogen activator,
• Publikační typ
• časopisecké články MeSH

Brain-derived neurotropic factor (BDNF) is an abundant and multi-function neurotrophin in the brain. It is released following neuronal activity and is believed to be particularly important in strengthening neural networks. A common variation in the BDNF gene, a valine to methionine substitution at codon 66 (Val66Met), has been linked to differential expression of BDNF associated with experience-dependent plasticity. The Met allele has been associated with reduced production of BDNF following neuronal stimulation, which suggests a potential role of this variation with respect to how the nervous system may respond to challenges, such as brain ageing and related neurodegenerative conditions (e.g., dementia and Alzheimer's disease). The current review examines the potential of the BDNF Val66Met variation to modulate an individual's susceptibility and trajectory through cognitive changes associated with ageing and dementia. On balance, research to date indicates that the BDNF Met allele at this codon is potentially associated with a detrimental influence on the level of cognitive functioning in older adults and may also impart increased risk of progression to dementia. Furthermore, recent studies also show that this genetic variation may modulate an individual's response to interventions targeted at building cognitive resilience to conditions that cause dementia.

• Klíčová slova
• Alzheimer’s disease, BDNF, BDNF Val66Met, ageing, brain-derived neurotrophic factor, cognitive function, dementia,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH