Peripheral chemokine receptors, their ligands, cytokines and Alzheimer's disease.

Cerebral inflammation as well as systemic immunological alterations has been reported in Alzheimer's disease (AD). We aimed to determine whether spontaneous and mitogen stimulated production of peripheral blood mononuclear cell (PBMC) cytokines, chemokines and chemokine receptors in clinically diagnosed patients with AD were unregulated. PBMC were purified from AD patients and from healthy controls. Supernatants were analyzed for cytokine levels by ELISA methods. mRNA expression was determined by RT-PCR. Expression of chemokine receptors CCR2 and CCR5 was determined by cytofluorimetric analysis. Both CCR5 and CCR2 expression were increased in AD patients respect to control subjects and the expression of CCR2 and CCR5 was more frequent on CD4+ and less frequent on CD8+ cells. Levels of Th1-type cytokine IFNgamma and chemokine RANTES were increased and levels of Th2-type cytokine IL-4 and chemokine MCP-1 were reduced in AD patients compared with those of control subjects. Acetylcholinesterase inhibitor pyridostigmine bromide (AChEI)-therapy reduced CCR2, CCR5, RANTES and IFNgamma expression and production in AD patients. CCR5, CCL5/RANTES, CCL2/MCP-1 and IFNgamma expression and production were increased in PBMC treated with amyloid-beta1-42. Addition of AChEI to PBMC suppresses CCL5/RANTES and IFNgamma. The observed patterns of cyto-chemokine involvement strengthen the questions regarding the inflammatory theory in AD, and raise a pathophysiologic role for selective alteration of cyto-chemokine network.

The acetylcholinesterase inhibitor, Donepezil, regulates a Th2 bias in Alzheimer's disease patients.

The increased pro-inflammatory cytokine production was previously observed in Alzheimer's disease (AD). We sought to explore whether acetylcholinesterase inhibitor (AChEI) therapy ameliorates clinical symptoms in AD through down-regulation of inflammation. Expression and release of monocyte chemotactic protein-1 (MCP-1), a positive regulator of Th2 differentiation, and interleukin (IL)-4, an anti-inflammatory cytokine from peripheral blood mononuclear cells (PBMC) in AD patients, were investigated. PBMC were purified from AD patients at time of enrollment (T0) and after 1 month of treatment with AChEI (T1) and from healthy controls (HC). Supernatants were analyzed for cytokine levels by ELISA methods. mRNA expression were determined by RT-PCR. Expression and production of MCP-1 and IL-4 were significantly increased in AD subjects under therapy with the AChEI Donepezil, compared to the same AD patients at time of enrollment (P < 0.001). Our data suggest another possible explanation for the ability of Donepezil [diethyl(3,5-di-ter-butyl-4-hydroxybenzyl)phosphonate] to delay the progression of AD; in fact, Donepezil may modulate MCP-1 and IL-4 production, which may reflect a general shift towards type Th0/Th2 cytokines which could be protective in AD disease. The different amounts of MCP-1 and IL-4 observed might reflect the different states of activation and/or responsiveness of PBMC, that in AD patients could be kept in an activated state by pro-inflammatory cytokines.

Expression and production of two selected beta-chemokines in peripheral blood mononuclear cells from patients with Alzheimer's disease.

MCP-1 and RANTES are molecules that regulate monocyte and T-lymphocyte recruitment towards sites of inflammation. We sought to evaluate the role of these chemokines in Alzheimer's disease (AD), and the effect of acetylcholinesterase inhibitor (AchEI) therapy on their release from peripheral blood mononuclear cells (PBMC). MCP-1 and RANTES mRNA expressions were determined by RT-PCR and the amount of secreted chemokines was assayed using specific ELISA methods from purified PBMC from each AD patients (n = 40) at the time of enrolment (T0) and after 1 month of treatment with AchEI (T1) and from 20 healthy age and sex-matched subjects (HC). We found that expression and production of MCP-1 in AD patients was significantly lower than in HC subjects. After 1 month of therapy with AchEI (Donepezil), MCP-1 levels increased in each patient. However, higher levels were detected for RANTES in AD patients compared to control subjects and in AD patients treated with Donepezil. MCP-1 and RANTES have a compensatory role in balancing the impaired mechanisms involved in immune response during ageing. Our present findings suggest that these two chemokines are both involved in AD pathogenesis and might reflect different states of activation and/or responsiveness of PBMC from AD patients, contributing to the impaired of the peripheral immune system in these patients.

Acetylcholinesterase inhibitors effects on oncostatin-M, interleukin-1 beta and interleukin-6 release from lymphocytes of Alzheimer's disease patients.

Many factors are involved in the pathogenesis of Alzheimer's disease (AD), and inflammatory-immunologic activation seems to play a major role. One strategy for treatment of AD has been to use acetylcholinesterase (AChE) inhibitors to increase the levels of acetylcholine and enhancing cholinergic activity in the affected regions of the brain. Cholinergic compounds modulate the immune system, therefore secretion, by peripheral blood mononuclear cells (PBMC), of cytokines was investigated in age-matched controls and in AD patients. Cytokines released by PBMC from AD patients enrolled as pre-treatment patients (T0) and as post-treatment with AchEI (T1), were detected by ELISA assay. The result showed an increase in oncostatin M, interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) secretion in AD patients compared to healthy controls, and a decrease of cytokine levels in each AD patients treated for 1 month with an acetylcholinesterase inhibitor (AchEI). In conclusion, the results of this study show that the complex pathology in AD may be reflected in a pattern of altered cytokine secretion from PBMC.

Interferon beta normalizes suppressor cell function in dysimmune neuropathies.

We found a defective suppressor cell function in vitro both in idiopathic chronic inflammatory demyelinating polyneuropathy and in paraproteinemic neuropathy with antibodies to sulfated glucuronyl paragloboside. In the presence of interferon beta, suppressor cell function was normalized. Our results suggest that a decreased suppressor cell function plays a pathogenetic role in dysimmune neuropathies. Interferon beta might represent an adjunctive therapy in CIDP both acting on a defective blood-nerve barrier and normalizing an otherwise defective suppressor cell function.

Interferon beta-1b modulates MCP-1 expression and production in relapsing-remitting multiple sclerosis.

Monocyte chemoattractant protein-1 (MCP-1) seems to be involved in the pathogenesis of multiple sclerosis (MS). We found that in unstimulated (PHA(-)) and PHA-stimulated (PHA(+)) peripheral blood mononuclear cells (PBMC), MCP-1 and TNFalpha levels are higher in stable untreated MS patients. Interferon gamma (IFNgamma) is higher in relapsing patients in PHA(-) cultures and in stable patients in PHA(+) cultures. Chronic IFNbeta-1b treatment down-regulates TNFalpha, IFNgamma and MCP-1 production except for TNFalpha in relapsing patients. IFNbeta-1b, in vitro, increases MCP-1, TNFalpha and IFNgamma spontaneous production in all patients. Multivariate analysis suggests that MCP-1 production is dependent from clinical status and not from TNFalpha and IFNgamma production. Logistic regression analysis shows that MCP-1 production is significantly modified by treatment. Further studies are needed to clarify the role of MCP-1 in MS.

Treatment with an acetylcholinesterase inhibitor in Alzheimer patients modulates the expression and production of the pro-inflammatory and anti-inflammatory cytokines.

Elevated levels of cytokines have been detected in brains of Alzheimer's disease (AD) patients, and altered peripheral levels of IL-1beta, TNFalpha and IL-6 have been reported in these patients. We studied the ability of PBMC from patients with AD, matched with a control group, to release pro- and anti-inflammatory cytokines, and the effect of AChEI treatment on cytokine release. Our data indicates that AChEI treatment down-regulates IL-1, IL-6 and TNF, and up-regulates the expression and production of IL-4 in PBMC in AD patients, and that AChEI leads to the remodelling of the cytokine network, probably acting on the lymphocytic cholinergic system.

Proinflammatory cytokines in sera of elderly patients with dementia: levels in vascular injury are higher than those of mild-moderate Alzheimer's disease patients.

Cognitive functions display a progressive impairment with ageing, and this is thought to be due to the accumulation of neuronal loss or acute and/or repeated microvascular accidents. Chronic damage to the brain cortex lead to decreasing ability of elderly subjects to cope with daily events and ultimately result in loss of self-sufficiency. Since proinflammatory cytokines have been implicated both in cerebrovascular injury due to atherosclerosis and in Alzheimer's disease (AD), we investigated 70 elderly subjects with neurocognitive and functional impairment. Diagnosis was established in 54, the others were included in the "mixed" group. Sera were collected and stored at -70 degrees C until measurement of IL-1beta and TNF-alpha, performed by commercial ELISA kits. Data obtained were analysed with respect to other socio-demographic, psychoneurological and clinical variables. The results show that serum TNF-alpha was lower in mild-moderate AD compared to severe AD and dementias due to vascular disease, as well as the TNF-alpha/IL-1beta ratio. Both cytokines showed a significant relationship with age. Our study suggests that proinflammatory cytokines serum profiles seem to discriminate between mild-moderate AD and vascular or mixed forms of dementia. Furthermore, it offers new evidence of a strong implication of inflammatory mechanisms in atherosclerosis, more than in less severe AD.

IL-4 in vitro production is upregulated in Alzheimer's disease patients treated with acetylcholinesterase inhibitors.

Cytokines appear to be involved in the pathogenesis of Alzheimer's Disease (AD). Their modulation by treatment has been investigated only in a few studies. The aim of our study was to evaluate the effect of acetylcholinesterase inhibitors (AChEI) on Interleukin-4 (IL-4) production in AD patients. IL-4 levels were measured by ELISA on peripheral blood mononuclear cell cultures in the presence or absence of Concanavalin A or Phytohaemagglutinin. Linear regression analysis shows that patients who have been treated, have higher levels of IL-4 independently from age, gender and comorbidity. The increased production of IL-4 in AChEI treated patients might represent an additional mechanism through which AChEI act on AD progression.

Alzheimer patients treated with an AchE inhibitor show higher IL-4 and lower IL-1 beta levels and expression in peripheral blood mononuclear cells.

The study evaluates the expression and production of cytokines in peripheral blood mononuclear cells of patients with Alzheimer disease treated or not treated with acetylcholinesterase inhibitor, which enhances neuronal transmission. Cytokines associated with brain inflammation such as interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha have been implicated in the regulation of amyloid peptide protein synthesis. The anti-inflammatory cytokine, IL-4, may suppress the activity of IL-1beta. Patients were assessed for clinical and immunologic features at baseline and after 1 month of treatment with Donepezil, an acetylcholinesterase inhibitor. Peripheral blood mononuclear cells were cultured with and without phytohemagglutinin stimulation. IL-1beta and IL-4 levels were measured by enzyme-linked immunosorbent assay. Reverse transcriptase-polymerase chain reaction was used to determine the expression of cytokines in peripheral mononuclear cells. Compared with untreated patients and healthy control subjects, IL-1beta levels and expression decreased in Alzheimer disease patients treated with Donepezil (P < 0.001). In contrast, IL-4 levels and expression were significantly higher in Alzheimer patients treated with the acetylcholinesterase inhibitor. This increment was observed in both unstimulated and phytohemagglutinin-stimulated peripheral blood mononuclear cells.