Serum cytokine levels in patients with Alzheimer's disease

Targeting TNF-α: The therapeutic potential of certolizumab pegol in the early period of cerebral ischemia reperfusion injury in mice

The neuroinflammatory response triggered by cerebral ischemia-reperfusion injury (CIRI) is characterized by the upsurge of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, which promote leukocyte infiltration and subsequent accumulation in the ischemic zone. This accumulation further intensifies inflammation and aggravates ischemic damage. Certolizumab pegol (CZP), a monoclonal antibody targeting TNF-α, is widely used in treating various inflammatory diseases. This study explored the therapeutic potential of CZP in a mouse model of CIRI, induced by middle cerebral artery occlusion (MCAO), focusing on its influence on the microglial inflammatory response. In vitro analyses revealed that CZP markedly inhibits TNF-α-stimulated inflammation in primary microglia with an EC50 of 1.743 ng/mL. In vivo, MCAO mice treated with CZP (10 μg/mouse, i.p.) for 3 days showed reduced infarct volume, partially improved neurological function, and diminished blood-brain barrierdisruption. Additionally, CZP treatment curtailed microglial activation and the release of pro-inflammatory mediators in the early stages of stroke. It also favorably modulated microglial M1/M2 polarization, rebalanced Th17/Treg cells dynamics, and inhibited Caspase-8-mediated GSDMD cleavage, preventing microglial pyroptosis. Collectively, this study described that the treatment with CZP reversed damaging process caused by CIRI, offering a promising therapeutic strategy for the treatment of ischemic stroke.

miRNAs in cerebrospinal fluid associated with Alzheimer's disease: A systematic review and pathway analysis using a data mining and machine learning approach

Alzheimer's disease (AD) is the most common type and accounts for 60%-70% of the reported cases of dementia. MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in gene expression regulation. Although the diagnosis of AD is primarily clinical, several miRNAs have been associated with AD and considered as potential markers for diagnosis and progression of AD. We sought to match AD-related miRNAs in cerebrospinal fluid (CSF) found in the GeoDataSets, evaluated by machine learning, with miRNAs listed in a systematic review, and a pathway analysis. Using machine learning approaches, we identified most differentially expressed miRNAs in Gene Expression Omnibus (GEO), which were validated by the systematic review, using the acronym PECO-Population (P): Patients with AD, Exposure (E): expression of miRNAs, Comparison (C): Healthy individuals, and Objective (O): miRNAs differentially expressed in CSF. Additionally, pathway enrichment analysis was performed to identify the main pathways involving at least four miRNAs selected. Four miRNAs were identified for differentiating between patients with and without AD in machine learning combined to systematic review, and followed the pathways analysis: miRNA-30a-3p, miRNA-193a-5p, miRNA-143-3p, miRNA-145-5p. The pathways epidermal growth factor, MAPK, TGF-beta and ATM-dependent DNA damage response, were regulated by these miRNAs, but only the MAPK pathway presented higher relevance after a randomic pathway analysis. These findings have the potential to assist in the development of diagnostic tests for AD using miRNAs as biomarkers, as well as provide understanding of the relationship between different pathophysiological mechanisms of AD.

Anti-Inflammatory Effects of Allocryptopine via the Target on the CX3CL1-CX3CR1 axis/GNB5/AKT/NF-κB/Apoptosis in Dextran Sulfate-Induced Mice

Allocryptopine (ALL) is an isoquinoline alkaloid extracted from Macleaya cordata(Willd). R. Br., which has been claimed to have anti-inflammatory and neuroprotection properties. However, the mechanism by which ALL ameliorates inflammatory bowel disease (IBD) remains unclear. Here, we used network pharmacology and quantitative proteomic approaches to investigate the effect of ALL on IBD pathogenesis. Network pharmacology predicted potential targets and signaling pathways of ALL's anti-IBD effects. As predicted by network pharmacology, gene ontology (GO) analysis, in terms of the proteomic results, showed that the immune response in mucosa and antimicrobial humoral response were enriched. Further study revealed that the ALL-related pathways were the chemokine signaling pathway and apoptosis in the Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, we identified AKT1 as a hub for the critical pathways through protein-protein interaction (PPI) network analysis. Similar to mesalazine (MES), Western blot verified that ALL downregulated upstream chemokine CX3CL1 and GNB5 content to reduce phosphorylation of AKT and NF-κB, as well as the degree of apoptosis, to improve inflammatory response in the colon. Our research may shed light on the mechanism by which ALL inhibits the CX3CL1/GNB5/AKT2/NF-κB/apoptosis pathway and improves the intestinal barrier to reduce colitis response and act on the CX3CL1-CX3CR1 axis to achieve neuroprotection.

Combined metabolic activators improve cognitive functions in Alzheimer's disease patients: a randomised, double-blinded, placebo-controlled phase-II trial

BACKGROUND

Alzheimer's disease (AD) is associated with metabolic abnormalities linked to critical elements of neurodegeneration. We recently administered combined metabolic activators (CMA) to the AD rat model and observed that CMA improves the AD-associated histological parameters in the animals. CMA promotes mitochondrial fatty acid uptake from the cytosol, facilitates fatty acid oxidation in the mitochondria, and alleviates oxidative stress.

METHODS

Here, we designed a randomised, double-blinded, placebo-controlled phase-II clinical trial and studied the effect of CMA administration on the global metabolism of AD patients. One-dose CMA included 12.35 g L-serine (61.75%), 1 g nicotinamide riboside (5%), 2.55 g N-acetyl-L-cysteine (12.75%), and 3.73 g L-carnitine tartrate (18.65%). AD patients received one dose of CMA or placebo daily during the first 28 days and twice daily between day 28 and day 84. The primary endpoint was the difference in the cognitive function and daily living activity scores between the placebo and the treatment arms. The secondary aim of this study was to evaluate the safety and tolerability of CMA. A comprehensive plasma metabolome and proteome analysis was also performed to evaluate the efficacy of the CMA in AD patients.

RESULTS

We showed a significant decrease of AD Assessment Scale-cognitive subscale (ADAS-Cog) score on day 84 vs day 0 (P = 0.00001, 29% improvement) in the CMA group. Moreover, there was a significant decline (P = 0.0073) in ADAS-Cog scores (improvement of cognitive functions) in the CMA compared to the placebo group in patients with higher ADAS-Cog scores. Improved cognitive functions in AD patients were supported by the relevant alterations in the hippocampal volumes and cortical thickness based on imaging analysis. Moreover, the plasma levels of proteins and metabolites associated with NAD + and glutathione metabolism were significantly improved after CMA treatment.

CONCLUSION

Our results indicate that treatment of AD patients with CMA can lead to enhanced cognitive functions and improved clinical parameters associated with phenomics, metabolomics, proteomics and imaging analysis. Trial registration ClinicalTrials.gov NCT04044131 Registered 17 July 2019, https://clinicaltrials.gov/ct2/show/NCT04044131.

Primary cilia and ciliary signaling pathways in aging and age-related brain disorders

Brain disorders are characterized by the progressive loss of structure and function of the brain as a consequence of progressive degeneration and/or death of nerve cells. Aging is a major risk factor for brain disorders such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and stroke. Various cellular and molecular events have been shown to play a role in the progress of neurodegenerative diseases. Emerging studies suggest that primary cilia could be a key regulator in brain diseases. The primary cilium is a singular cellular organelle expressed on the surface of many cell types, such as astrocytes and neurons in the mature brain. Primary cilia detect extracellular cues, such as Sonic Hedgehog (SHH) protein, and transduce these signals into cells to regulate various signaling pathways. Abnormalities in ciliary length and frequency (ratio of ciliated cells) have been implicated in various human diseases, including brain disorders. This review summarizes current findings and thoughts on the role of primary cilia and ciliary signaling pathways in aging and age-related brain disorders.

The Association of Blood-Based Inflammatory Factors IL-1β, TGF-β and CRP with Cognitive Function in Alzheimer's Disease and Mild Cognitive Impairment

OBJECTIVE

Many patients suffer from dementia in its most common form, Alzheimer's disease (AD). In this study, the levels of IL-1β, TGF-β and CRP, which are involved in the inflammatory response in Alzheimer's disease and its mild cognitive impairment (MCI), were measured and analyzed.

METHODS

Seventy nine subjects participated in this study (mean age: 75.56 years, female: 54.3%, AD: 26, MCI: 28, normal: 25). The overall cognitive function of the subjects and the severity of the disease stage were assessed using the Mini-Mental State Examination (MMSE-K), the Clinical Dementia Rating (CDR), the Global Deterioration Scale (GDS) and the Geriatric Depression Scale-Korean (GDS-K).

RESULTS

It was observed that patients with AD had significantly higher levels of IL-1β and TGF-β than the patients with MCI and normal controls. In addition, the MCI group showed a statistically significantly higher TGF-β concentration than the normal group.

CONCLUSION

These results suggest that IL-1β and TGF-β may be useful biological markers for patients with Alzheimer's disease.

Multiple Roles of Transforming Growth Factor Beta in Amyotrophic Lateral Sclerosis

Transforming growth factor beta (TGFB) is a pleiotropic cytokine known to be dysregulated in many neurodegenerative disorders and particularly in amyotrophic lateral sclerosis (ALS). This motor neuronal disease is non-cell autonomous, as it affects not only motor neurons but also the surrounding glial cells, and the target skeletal muscle fibers. Here, we analyze the multiple roles of TGFB in these cell types, and how TGFB signaling is altered in ALS tissues. Data reported support a crucial involvement of TGFB in the etiology and progression of ALS, leading us to hypothesize that an imbalance of TGFB signaling, diminished at the pre-symptomatic stage and then increased with time, could be linked to ALS progression. A reduced stimulation of the TGFB pathway at the beginning of disease blocks its neuroprotective effects and promotes glutamate excitotoxicity. At later disease stages, the persistent activation of the TGFB pathway promotes an excessive microglial activation and strengthens muscular dysfunction. The therapeutic potential of TGFB is discussed, in order to foster new approaches to treat ALS.

Excessive Production of Transforming Growth Factor β1 Causes Mural Cell Depletion From Cerebral Small Vessels

It is increasingly becoming apparent that cerebrovascular dysfunction contributes to the pathogenic processes involved in vascular dementia, Alzheimer’s disease, and other neurodegenerative disorders. Under these pathologic conditions, the degeneration of cerebral blood vessels is frequently accompanied by a loss of mural cells from the vascular walls. Vascular mural cells play pivotal roles in cerebrovascular functions, such as regulation of cerebral blood flow and maintenance of the blood-brain barrier (BBB). Therefore, cerebrovascular mural cell impairment is involved in the pathophysiology of vascular-related encephalopathies, and protecting these cells is essential for maintaining brain health. However, our understanding of the molecular mechanism underlying mural cell abnormalities is incomplete. Several reports have indicated that dysregulated transforming growth factor β (TGFβ) signaling is involved in the development of cerebral arteriopathies. These studies have specifically suggested the involvement of TGFβ overproduction. Although cerebrovascular toxicity via vascular fibrosis by extracellular matrix accumulation or amyloid deposition is known to occur with enhanced TGFβ production, whether increased TGFβ results in the degeneration of vascular mural cells in vivo remains unknown. Here, we demonstrated that chronic TGFβ1 overproduction causes a dropout of mural cells and reduces their coverage on cerebral vessels in both smooth muscle cells and pericytes. Mural cell degeneration was also accompanied by vascular luminal dilation. TGFβ1 overproduction in astrocytes significantly increased TGFβ1 content in the cerebrospinal fluid (CSF) and increased TGFβ signaling-regulated gene expression in both pial arteries and brain capillaries. These results indicate that TGFβ is an important effector that mediates mural cell abnormalities under pathological conditions related to cerebral arteriopathies.

If ineffective levels of transforming growth factors and their receptor account for old age being a risk factor for Alzheimer's disease, then increasing TGFBR2 might be therapeutic

If it is correct that ineffective levels of transforming growth factors beta and their receptor account for old age being a risk factor for Alzheimer's disease (AD), then increasing TGFBR2 might be therapeutic. Pacltaxel is a direct way to increase TGFBR2 levels. Indirect ways that will increase TGFBR2, include decreasing the levels of c-myc because that will lower the miRNA cluster 17-92, particularly its miR-17 and miR-20a components; and raising EGFR because that also will increase TGFBR2. Metformin and desferrioxamine are drugs that decrease c-myc; and statins increase levels of EGF. Clinical trials using those drugs, would demonstrate whether they decrease the progression from amnestic mild cognitive impairment to AD.

Ineffective levels of transforming growth factors and their receptor account for old age being a risk factor for Alzheimer's disease

After the midninth decade of age, the incidence rates of Alzheimer's disease (AD) and the presence of active TGF-β1 show comparable increases. The hypothesis is proposed that the reason why advanced age is a major risk factor for AD is a progressive decrease with advancing age in the numbers of TGFR2 receptors in the brain, with the consequence of a decline in the neurotrophic efficacy of TGF-β1 and 2 despite their already increased levels in older persons. Alternative, possible reasons are discussed but rejected because either those reasons may also affect young persons or because they cannot be validated in a clinical trial. The proposed hypothesis may be validated in persons with aMCI after raising their brain levels of TGF-β1 and 2 by using a combination of three drugs, lithium, memantine, plus either glatiramer or venlafaxine, and then assessing their progression to AD.

Exploiting microglial and peripheral immune cell crosstalk to treat Alzheimer's disease

Neuroinflammation is considered one of the cardinal features of Alzheimer’s disease (AD). Neuritic plaques composed of amyloid β and neurofibrillary tangle-laden neurons are surrounded by reactive astrocytes and microglia. Exposure of microglia, the resident myeloid cell of the CNS, to amyloid β causes these cells to acquire an inflammatory phenotype. While these reactive microglia are important to contain and phagocytose amyloid plaques, their activated phenotype impacts CNS homeostasis. In rodent models, increased neuroinflammation promoted by overexpression of proinflammatory cytokines can cause an increase in hyperphosphorylated tau and a decrease in hippocampal function. The peripheral immune system can also play a detrimental or beneficial role in CNS inflammation. Systemic inflammation can increase the risk of developing AD dementia, and chemokines released directly by microglia or indirectly by endothelial cells can attract monocytes and T lymphocytes to the CNS. These peripheral immune cells can aid in amyloid β clearance or modulate microglia responses, depending on the cell type. As such, several groups have targeted the peripheral immune system to modulate chronic neuroinflammation. In this review, we focus on the interplay of immunomodulating factors and cell types that are being investigated as possible therapeutic targets for the treatment or prevention of AD.

Similarity and Differences in Inflammation-Related Characteristics of the Peripheral Immune System of Patients with Parkinson's and Alzheimer's Diseases

Parkinson's disease (PD) and Alzheimer's disease (AD) are the most common age-related neurodegenerative disorders. Both diseases are characterized by chronic inflammation in the brain-neuroinflammation. The first signs of PD and AD are most often manifested in old age, in which the immune system is usually characterized by chronic inflammation, so-called "inflammaging" In recent years, there is growing evidence that pathogenesis of these diseases is connected with both regional and peripheral immune processes. Currently, the association of clinical signs of PD and AD with different characteristics of patient immune status is actively being researched. In this mini-review we compare the association of PD and AD alterations of a number of immune system parameters connected with the process of inflammation.

Let's make microglia great again in neurodegenerative disorders

All of the common neurodegenerative disorders-Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and prion diseases-are characterized by accumulation of misfolded proteins that trigger activation of microglia; brain-resident mononuclear phagocytes. This chronic form of neuroinflammation is earmarked by increased release of myriad cytokines and chemokines in patient brains and biofluids. Microglial phagocytosis is compromised early in the disease process, obfuscating clearance of abnormal proteins. This review identifies immune pathologies shared by the major neurodegenerative disorders. The overarching concept is that aberrant innate immune pathways can be targeted for return to homeostasis in hopes of coaxing microglia into clearing neurotoxic misfolded proteins.

Targeting Neuroinflammation to Treat Alzheimer's Disease

Over the past few decades, research on Alzheimer's disease (AD) has focused on pathomechanisms linked to two of the major pathological hallmarks of extracellular deposition of beta-amyloid peptides and intra-neuronal formation of neurofibrils. Recently, a third disease component, the neuroinflammatory reaction mediated by cerebral innate immune cells, has entered the spotlight, prompted by findings from genetic, pre-clinical, and clinical studies. Various proteins that arise during neurodegeneration, including beta-amyloid, tau, heat shock proteins, and chromogranin, among others, act as danger-associated molecular patterns, that-upon engagement of pattern recognition receptors-induce inflammatory signaling pathways and ultimately lead to the production and release of immune mediators. These may have beneficial effects but ultimately compromise neuronal function and cause cell death. The current review, assembled by participants of the Chiclana Summer School on Neuroinflammation 2016, provides an overview of our current understanding of AD-related immune processes. We describe the principal cellular and molecular players in inflammation as they pertain to AD, examine modifying factors, and discuss potential future therapeutic targets.

TGF-beta1 regulates human brain pericyte inflammatory processes involved in neurovasculature function

Background

Transforming growth factor beta 1 (TGFβ₁) is strongly induced following brain injury and polarises microglia to an anti-inflammatory phenotype. Augmentation of TGFβ₁ responses may therefore be beneficial in preventing inflammation in neurological disorders including stroke and neurodegenerative diseases. However, several other cell types display immunogenic potential and identifying the effect of TGFβ₁ on these cells is required to more fully understand its effects on brain inflammation. Pericytes are multifunctional cells which ensheath the brain vasculature and have garnered recent attention with respect to their immunomodulatory potential. Here, we sought to investigate the inflammatory phenotype adopted by TGFβ₁-stimulated human brain pericytes.

Methods

Microarray analysis was performed to examine transcriptome-wide changes in TGFβ₁-stimulated pericytes, and results were validated by qRT-PCR and cytometric bead arrays. Flow cytometry, immunocytochemistry and LDH/Alamar Blue® viability assays were utilised to examine phagocytic capacity of human brain pericytes, transcription factor modulation and pericyte health.

Results

TGFβ₁ treatment of primary human brain pericytes induced the expression of several inflammatory-related genes (NOX4, COX2, IL6 and MMP2) and attenuated others (IL8, CX3CL1, MCP1 and VCAM1). A synergistic induction of IL-6 was seen with IL-1β/TGFβ₁ treatment whilst TGFβ₁ attenuated the IL-1β-induced expression of CX3CL1, MCP-1 and sVCAM-1. TGFβ₁ was found to signal through SMAD2/3 transcription factors but did not modify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation. Furthermore, TGFβ₁ attenuated the phagocytic ability of pericytes, possibly through downregulation of the scavenger receptors CD36, CD47 and CD68. Whilst TGFβ did decrease pericyte number, this was due to a reduction in proliferation, not apoptotic death or compromised cell viability.

Conclusions

TGFβ₁ attenuated pericyte expression of key chemokines and adhesion molecules involved in CNS leukocyte trafficking and the modulation of microglial function, as well as reduced the phagocytic ability of pericytes. However, TGFβ₁ also enhanced the expression of classical pro-inflammatory cytokines and enzymes which can disrupt BBB functioning, suggesting that pericytes adopt a phenotype which is neither solely pro- nor anti-inflammatory. Whilst the effects of pericyte modulation by TGFβ₁ in vivo are difficult to infer, the reduction in pericyte proliferation together with the elevated IL-6, MMP-2 and NOX4 and reduced phagocytosis suggests a detrimental action of TGFβ₁ on neurovasculature.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0503-0) contains supplementary material, which is available to authorized users.

Chronic fatigue syndrome and circulating cytokines: A systematic review

There has been much interest in the role of the immune system in the pathophysiology of chronic fatigue syndrome (CFS), as CFS may develop following an infection and cytokines are known to induce acute sickness behaviour, with similar symptoms to CFS. Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines, a search was conducted on PubMed, Web of Science, Embase and PsycINFO, for CFS related-terms in combination with cytokine-related terms. Cases had to meet established criteria for CFS and be compared with healthy controls. Papers retrieved were assessed for both inclusionary criteria and quality. 38 papers met the inclusionary criteria. The quality of the studies varied. 77 serum or plasma cytokines were measured without immune stimulation. Cases of CFS had significantly elevated concentrations of transforming growth factor-beta (TGF-β) in five out of eight (63%) studies. No other cytokines were present in abnormal concentrations in the majority of studies, although insufficient data were available for some cytokines. Following physical exercise there were no differences in circulating cytokine levels between cases and controls and exercise made no difference to already elevated TGF-β concentrations. The finding of elevated TGF-β concentration, at biologically relevant levels, needs further exploration, but circulating cytokines do not seem to explain the core characteristic of post-exertional fatigue.

TGF-β1 protection against Aβ1-42-induced neuroinflammation and neurodegeneration in rats

Transforming growth factor (TGF)-β1, a cytokine that can be expressed in the brain, is a key regulator of the brain's responses to injury and inflammation. Alzheimer's disease (AD), the most common neurodegenerative disorder, involves inflammatory processes in the brain in addition to the hallmarks, amyloid-β (Aβ) plaques and neurofibrillary tangles. Recently, we have shown that T-helper (Th) 17 cells, a subpopulation of CD4+ T-cells with high proinflammation, also participate in the brain inflammatory process of AD. However, it is poorly known whether TGF-β1 ameliorates the lymphocyte-mediated neuroinflammation and, thereby, alleviates neurodegeneration in AD. Herein, we administered TGF-β1 via the intracerebroventricle (ICV) in AD model rats, by Aβ1-42 injection in both sides of the hippocampus, to show the neuroprotection of TGF-β1. The TGF-β1 administration after the Aβ1-42 injection ameliorated cognitive deficit and neuronal loss and apoptosis, reduced amyloid precursor protein (APP) expression, elevated protein phosphatase (PP)2A expression, attenuated glial activation and alleviated the imbalance of the pro-inflammatory/anti-inflammatory responses of T-lymphocytes, compared to the Aβ1-42 injection alone. These findings demonstrate that TGF-β1 provides protection against AD neurodegeneration and suggest that the TGF-β1 neuroprotection is implemented by the alleviation of glial and T-cell-mediated neuroinflammation.

The role of the immune system in neurodegenerative disorders: Adaptive or maladaptive?

Neurodegenerative diseases share common features, including catastrophic neuronal loss that leads to cognitive or motor dysfunction. Neuronal injury occurs in an inflammatory milieu that is populated by resident and sometimes, infiltrating, immune cells - all of which participate in a complex interplay between secreted inflammatory modulators and activated immune cell surface receptors. The importance of these immunomodulators is highlighted by the number of immune factors that have been associated with increased risk of neurodegeneration in recent genome-wide association studies. One of the more difficult tasks for designing therapeutic strategies for immune modulation against neurodegenerative diseases is teasing apart beneficial from harmful signals. In this regard, learning more about the immune components of these diseases has yielded common themes. These unifying concepts should eventually enable immune-based therapeutics for treatment of Alzheimer׳s and Parkinson׳s diseases and amyotrophic lateral sclerosis. Targeted immune modulation should be possible to temper maladaptive factors, enabling beneficial immune responses in the context of neurodegenerative diseases. This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Body fluid cytokine levels in mild cognitive impairment and Alzheimer's disease: a comparative overview

This article gives a comprehensive overview of cytokine and other inflammation associated protein levels in plasma, serum and cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). We reviewed 118 research articles published between 1989 and 2013 to compare the reported levels of 66 cytokines and other proteins related to regulation and signaling in inflammation in the blood or CSF obtained from MCI and AD patients. Several cytokines are evidently regulated in (neuro-) inflammatory processes associated with neurodegenerative disorders. Others do not display changes in the blood or CSF during disease progression. However, many reports on cytokine levels in MCI or AD are controversial or inconclusive, particularly those which provide data on frequently investigated cytokines like tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6). The levels of several cytokines are possible indicators of neuroinflammation in AD. Some of them might increase steadily during disease progression or temporarily at the time of MCI to AD conversion. Furthermore, elevated body fluid cytokine levels may correlate with an increased risk of conversion from MCI to AD. Yet, research results are conflicting. To overcome interindividual variances and to obtain a more definite description of cytokine regulation and function in neurodegeneration, a high degree of methodical standardization and patients collective characterization, together with longitudinal sampling over years is essential.

Potential blood biomarker for disease severity in the Taiwanese population with Alzheimer's disease

The identification of blood biomarkers for Alzheimer's disease (AD) could contribute for improvement in early diagnosis. To define AD biomarkers, we compared serum/plasma levels of amyloid β (Aβ), tau, cytokines, and biometals between AD and non-AD groups. Cognitive impairment was assessed by Mini-Mental Status Examination (MMSE) and Clinical Dementia Rating scales. Plasma concentrations of total Aβ, Aβ(42), tumor necrosis factor α (TNF-α), and interleukin 6 were quantified by immunoassays. Serum biometal concentrations were determined using flame atomic absorption spectrometry. We found that serum zinc (Zn) was lower in patients with AD. After controlling for age, the MMSE score correlated with both TNF-α and total Aβ levels in the AD group, while the MMSE score correlated with iron only in the non-AD group. Our finding that blood Zn, TNF-α, and total Aβ are possible biomarkers for AD diagnosis and prognosis validates the pervious publication on potential biomarker in the Taiwanese population.

A review: inflammatory process in Alzheimer's disease, role of cytokines

Alzheimer's disease (AD) is the most common neurodegenerative disorder to date. Neuropathological hallmarks are β-amyloid (Aβ) plaques and neurofibrillary tangles, but the inflammatory process has a fundamental role in the pathogenesis of AD. Inflammatory components related to AD neuroinflammation include brain cells such as microglia and astrocytes, the complement system, as well as cytokines and chemokines. Cytokines play a key role in inflammatory and anti-inflammatory processes in AD. An important factor in the onset of inflammatory process is the overexpression of interleukin (IL)-1, which produces many reactions in a vicious circle that cause dysfunction and neuronal death. Other important cytokines in neuroinflammation are IL-6 and tumor necrosis factor (TNF)-α. By contrast, other cytokines such as IL-1 receptor antagonist (IL-1ra), IL-4, IL-10, and transforming growth factor (TGF)-β can suppress both proinflammatory cytokine production and their action, subsequently protecting the brain. It has been observed in epidemiological studies that treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) decreases the risk for developing AD. Unfortunately, clinical trials of NSAIDs in AD patients have not been very fruitful. Proinflammatory responses may be countered through polyphenols. Supplementation of these natural compounds may provide a new therapeutic line of approach to this brain disorder.

High serum levels of transforming growth factor β1 are associated with increased cortical thickness in cingulate and right frontal areas in healthy subjects

BACKGROUND

Transforming growth factor β (TGF-β) is a cytokine having multiple functions in the central nervous system such as promoting repair mechanisms in degenerative diseases and stroke. To date, however, its neuroprotective effects in non-disease conditions have not been studied

METHODS

With the aim of exploring the relationship between peripheral TGF-β1 expression and brain structural integrity, 70 healthy participants underwent high-resolution structural T1-weighted magnetic resonance imaging scans and blood sampling. Data were processed to obtain brain cortical thickness and serum concentrations of TGF-β1. We investigated the correlation between TGF-β1 and cortical thickness using both region-of-interest- and vertex-based approaches.

FINDINGS

Region-of-interest-based analysis of the cortical mantle showed a correlation between TGF-β1 serum concentrations and cortical thickness bilaterally in cingulate and right frontal and temporal areas. Similar results emerged in the vertex-based analysis, where significant correlations were found bilaterally in cingulate and right frontal cortices.

CONCLUSIONS

These results suggest that TGF-β1, through its role in down-regulating inflammatory processes, might have a beneficial effect on the structural integrity of the brain in physiological states.

The Impact of Maternal High-Fat Diet Consumption on Neural Development and Behavior of Offspring

Maternal diet and metabolic state are important factors in determining the environment experienced during perinatal development. Epidemiological studies and evidence from animal models provide evidence that a mother's diet and metabolic condition are important in programming the neural circuitry that regulates behavior, resulting in a persistent impact on the offspring's behavior. Potential mechanisms by which maternal diet and metabolic profile influence the perinatal environment include placental dysfunction and increases in circulating factors such as inflammatory cytokines, nutrients (glucose and fatty acids) and hormones (insulin and leptin). Maternal obesity and high-fat diet (HFD) consumption exposure during development have been observed to increase the risk of developing serious mental health and behavioral disorders including anxiety, depression, attention deficit hyperactivity disorder and autism spectrum disorder. The increased risk of developing these behavioral disorders is postulated to be due to perturbations in the development of neural pathways that regulate behavior, including the serotonergic, dopaminergic and melanocortinergic systems. It is critical to examine the influence that a mother's nutrition and metabolic profile have on the developing offspring considering the current and alarmingly high prevalence of obesity and HFD consumption in pregnant women.

Cerebrospinal fluid and blood biomarkers in Alzheimer’s disease

Due to an ever aging society and growing prevalence of Alzheimer’s disease (AD), the challenge to meet social and health care system needs will become increasingly difficult. Unfortunately, a definite ante mortem diagnosis is not possible. Thus, an early diagnosis and identification of AD patients is critical for promising, early pharmacological interventions as well as addressing health care needs. The most advanced and most reliable markers are β-amyloid, total tau and phosphorylated tau in cerebrospinal fluid (CSF). In blood, no single biomarker has been identified despite an intense search over the last decade. The most promising approaches consist of a combination of several blood-based markers increasing the reliability, sensitivity and specificity of the AD diagnosis. However, contradictory data make standardized testing methods in longitudinal and multi-center studies extremely difficult. In this review, we summarize a range of the most promising CSF and blood biomarkers for diagnosing AD.

Blood-based protein biomarkers for diagnosis and classification of neurodegenerative diseases: current progress and clinical potential

Biomarker research is a rapidly advancing field in medicine. Recent advances in genomic, genetic, epigenetic, neuroscientific, proteomic, and metabolomic knowledge and technologies have opened the way to thriving research. In the most general sense, a biomarker refers to any useful characteristic that can be measured and used as an indicator of a normal biologic process, a pathogenic process, or a pharmacologic response to a therapeutic agent. Despite the extensive resources concentrated on this area, there are very few biomarkers currently available that qualify and are satisfactorily validated for mental disorders, and there is still a major lack of biomarkers for typifying neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. This article provides an overview of this field of research and focuses on recent advances in biomarker research in Alzheimer's disease and Parkinson's disease.

The role of tumor necrosis factor-α and TNF-α receptors in cerebral arteries following cerebral ischemia in rat

Background

Tumour necrosis factor-α (TNF-α) is a pleiotropic pro-inflammatory cytokine, which is rapidly upregulated in the brain after injury. TNF-α acts by binding to its receptors, TNF-R1 (p55) and TNF-R2 (p75), on the cell surface. The aim of this study was first to investigate if there is altered expression of TNF-α and TNF-α receptors in cerebral artery walls following global or focal ischemia, and after organ culture. Secondly, we asked if the expression was regulated via activation of the MEK-ERK1/2 pathway.

Methods

The hypothesis was tested in vivo after subarachnoid hemorrhage (SAH) and middle cerebral artery occlusion (MCAO), and in vitro by organ culture of isolated cerebral arteries. The localization and amount of TNF-α, TNF-α receptor 1 and 2 proteins were analysed by immunohistochemistry and western blot after 24 and 48 h of organ culture and at 48 h following SAH or MCAO. In addition, cerebral arteries were incubated for 24 or 48 h in the absence or presence of a B-Raf inhibitor (SB386023-b), a MEK- inhibitor (U0126) or an NF-κB inhibitor (IMD-0354), and protein expression evaluated.

Results

Immunohistochemistry revealed enhanced expression of TNF-α, TNF-R1 and TNF-R2 in the walls of cerebral arteries at 48 h after MCAO and SAH compared with control. Co-localization studies showed that TNF-α, TNF-R1 and TNF-R2 were primarily localized to the cell membrane and the cytoplasm of the smooth muscle cells (SMC). There was, in addition, some expression of TNF-R2 in the endothelial cells. Immunohistochemistry and western blot analysis showed that these proteins were upregulated after 24 and 48 h in culture, and this upregulation reached an apparent maximum at 48 h of organ culture. Treatment with U0126 significantly reduced the enhanced SMC expression of TNF-α, TNF-R1 and TNF-R2 immunoreactivities after 24 and 48 h of organ culture. The Raf and NF-κB inhibitors significantly reduced organ culture induced TNF-α expression while they had minor effects on the TNF-α receptors.

Conclusion

The present study shows that cerebral ischemia and organ culture induce expression of TNF-α and its receptors in the walls of cerebral arteries and that upregulation is transcriptionally regulated via the MEK/ERK pathway.

APOE epsilon-4 allele and cytokine production in Alzheimer's disease

OBJECTIVE

The APOE epsilon-4 allele has consistently emerged as a susceptibility factor for Alzheimer's disease (AD). Pro-inflammatory cytokines are detectable at abnormal levels in AD, and are thought to play a pathophysiological role. Animal studies have shown dose-dependent correlations between the number of APOE epsilon-4 alleles and the levels of pro-inflammatory cytokines. The aims of this study were to investigate the influence of APOE genotypes on TNF-alpha, IL-6, and IL-1beta secreted by peripheral blood mononuclear cells (PBMC) from human patients with AD and to analyze the correlation between cytokine production and AD clinical features.

METHODS

Outpatients with AD (n = 40) were clinically evaluated for cognitive decline (MMSE) and psychiatric symptoms (Cornell Scale for Depression in Dementia; Neuropsychiatric Inventory) and genotyped for APOE variants. PBMCs were isolated from the donors and used to assess spontaneous and PMA-stimulated secretion of TNF-alpha, IL-6, and IL-1beta. Cytokine production was determined by immuno-enzymatic assays (ELISA).

RESULTS

In comparison with their counterparts without APOE4, patients with at least one copy of the APOE epsilon-4 allele showed higher spontaneous (p = 0.037) and PMA-induced (p = 0.039) production of IL-1beta after controlling for clinical variables. Significant correlations were reported between NPI scores (psychotic symptoms) and IL-6 production.

CONCLUSION

These preliminary findings suggest the involvement of inflammatory response in the pathogenic effect of the APOE epsilon-4 allele in AD, although their replication in larger samples is mandatory. The modest correlations between pro-inflammatory cytokines released at peripheral level and AD features emphasizes the need for further research to elucidate the role of neuroinflammation in pathophysiology of AD.

TGF-β1 pathway as a new target for neuroprotection in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder that affects more than 37 million people worldwide. Current drugs for AD are only symptomatic, but do not interfere with the underlying pathogenic mechanisms of the disease. AD is characterized by the presence of ß-amyloid (Aβ) plaques, neurofibrillary tangles, and neuronal loss. The identification of the molecular determinants underlying AD pathogenesis is a fundamental step to design new disease-modifying drugs. Recently, a specific impairment of transforming-growth-factor-β1 (TGF-β1) signaling pathway has been demonstrated in AD brain. The deficiency of TGF-β1 signaling has been shown to increase both Aβ accumulation and Aβ-induced neurodegeneration in AD models. The loss of function of TGF-ß1 pathway seems also to contribute to tau pathology and neurofibrillary tangle formation. Growing evidence suggests a neuroprotective role for TGF-β1 against Aβ toxicity both in vitro and in vivo models of AD. Different drugs, such as lithium or group II mGlu receptor agonists are able to increase TGF-β1 levels in the central nervous system (CNS), and might be considered as new neuroprotective tools against Aβ-induced neurodegeneration. In the present review, we examine the evidence for a neuroprotective role of TGF-β1 in AD, and discuss the TGF-β1 signaling pathway as a new pharmacological target for the treatment of AD.

Biological marker candidates of Alzheimer's disease in blood, plasma, and serum

At the earliest clinical stages of Alzheimer's disease (AD), when first symptoms are mild, making a reliable and accurate diagnosis is difficult. AD related brain pathology and underlying molecular mechanisms precede symptoms. Biological markers can serve as supportive early screening and diagnostic tools as well as indicators of presymptomatic biochemical change. Moreover, biomarkers cover a variety of roles and functions such as disease prediction, indicating disease acuity and progression, and may ensure biological mapping of treatment outcome. Early screening, detection, and diagnosis of AD would permit earlier disease modifying intervention at potentially reversible stages. To date, most established biological markers from both cerebrospinal fluid neurochemistry and structural and functional neuroimaging have not reached widespread clinical application. Crucial remaining problems, such as easy acceptance and application of a test, cost-effectiveness, and noninvasiveness, need to be resolved. The development and validation of precise, reliable, and robust tests and biomarkers in blood, plasma, or serum has therefore been for a long time the ultimate focus of many research groups worldwide. Blood-based testing will most likely be the prerequisite to future sensitive screening of large populations at risk of AD and the baseline in a diagnostic flow approach to AD. The status and emerging perspectives on hypothesis and exploratory-based candidate biomarkers derived from blood, plasma, and serum are reviewed and discussed.

Peripheral chemo-cytokine profiles in Alzheimer's and Parkinson's diseases

The identification of peripheral biomarkers for neurodegenerative diseases is required to improve the accuracy of clinical diagnosis and monitor both disease progression and response to treatments. The data reviewed in this paper suggest that, in neurodegenerative disease, cytokines are links between peripheral immune system and nervous system dysfunction.

Biomarkers for Alzheimer disease in cerebrospinal fluid, urine, and blood

Alzheimer disease is the most common cause of dementia, yet its clinical diagnosis remains uncertain until an eventual postmortem histopathology examination. Currently, therapy for patients with Alzheimer disease only treats the symptoms; however, it is anticipated that new disease-modifying drugs will soon become available.Diagnostic tools for detecting Alzheimer disease at an incipient stage that can reliably differentiate the disease from other forms of dementia are of key importance for optimal treatment. Biomarkers have the potential to aid in a correct diagnosis, and great progress has been made in the discovery and development of potentially useful biomarkers in recent years. This includes single protein biomarkers in the cerebrospinal fluid, as well as multi-component biomarkers, and biomarkers based on gene expression. Novel biomarkers that use blood and urine, the more easily available clinical samples, are also being discovered and developed. The plethora of potential biomarkers currently being investigated may soon provide biomarkers that fulfill different functions, not only for diagnostic purposes but also for drug development and to follow disease progression.

Dementia of the Alzheimer type

Dementia of the Alzheimer type is a progressive, fatal neurodegenerative condition characterized by deterioration in cognition and memory, progressive impairment in the ability to carry out activities of daily living, and a number of neuropsychiatric symptoms. This narrative review summarizes the literature regarding descriptive epidemiology, clinical course, and characteristic neuropathological changes of dementia of the Alzheimer type. Although there are no definitive imaging or laboratory tests, except for brain biopsy, for diagnosis, brief screening instruments and neuropsychiatric test batteries used to assess the disease are discussed. Insufficient evidence exists for the use of biomarkers in clinical practice for diagnosis or disease management, but promising discoveries are summarized. Optimal treatment requires both nonpharmacological and pharmacological interventions, yet none have been shown to modify the disease's clinical course. This review describes the current available options and summarizes promising new avenues for treatment. Issues related to the care of persons with dementia of the Alzheimer type, including caregiver burden, long-term care, and the proliferation of dementia special care units, are discussed. Although advances have been made, more research is needed to address the gaps in our understanding of the disease.

The role of the immune system in clearance of Abeta from the brain

In Alzheimer's disease (AD), there is abnormal accumulation of Abeta and tau proteins in the brain. There is an associated immunological response, but it is still unclear whether this is beneficial or harmful. Inflammation in AD, specifically in the form of microglial activation, has, for many years, been considered to contribute to disease progression. However, two types of evidence suggest that it may be appropriate to revise this view: first, the disappointing results of prospective clinical trials of anti-inflammatory agents and, second, the observation that microglia can clear plaques in AD following Abeta immunization. Although Abeta immunization alters AD pathology, there is limited evidence so far of benefit to cognitive function. Immunization against microorganisms is almost always used as a method of disease prevention rather than to treat a disease process that has already started. In animal models, immunotherapy at an early age can protect against Abeta accumulation and it will be interesting to see if this can usefully be applied to humans to prevent AD.

Serum levels and genetic variation of TGF-beta1 are not associated with Alzheimer's disease

OBJECTIVE

As transforming growth factor-beta1 (TGF-beta1) determines important neurotrophic and neuroprotective actions, we postulated serum TGF-beta1 levels could be low in Alzheimer's disease (AD), and TGF-beta1 genetic variation could be associated with AD risk through modulating serum TGF-beta1 levels.

METHODS

TGF-beta1 (-800) (rs 1800468), (-509) (rs 1800469) and (+869) (rs 1982073) polymorphisms were genotyped in 412 AD patients and 406 controls. We measured serum TGF-beta1 levels (by ELISA) in 63 AD patients and compared them with 77 age- and gender-matched non-demented controls.

RESULTS

Serum TGF-beta1 levels were not different in AD patients than in controls. Distribution of the allele and genotype frequencies of TGF-beta1 polymorphisms did not differ between AD patients and controls. There was no significant correlation between serum TGF-beta1 levels and TGF-beta1 polymorphisms.

CONCLUSION

Serum TGF-beta1 concentration is not a potential biomarker for AD, and TGF-beta1 genetic variants (-800, -509, and +869) are not risk factors for AD.

Reduced serum level of antibodies against amyloid beta peptide is associated with aging in Tg2576 mice

Both active and passive immunization to eliminate amyloid plaques from the brain of patients with Alzheimer's disease (AD) have confirmed that amyloid beta (Abeta) vaccination does not only result in clearance of Abeta plaques but improves behavioral-cognitive deficits in animal models of AD. In the present study, the levels of naturally occurring serum antibodies against Abeta were measured in Tg2576 mice at various ages using ELISA to determine the relationship between aging and the level of anti-Abeta autoantibody. The level of anti-Abeta antibody fell significantly at the age of 9 months, at the age when amyloid plaques started to appear in the brain of Tg2576 mice, and was persistently low thereafter. However, serum immunoglobulin (Ig) level was elevated in older transgenic mice compared with younger transgenic mice suggesting that the reduced level of anti-Abeta autoantibody was not merely due to deterioration of the immune response in aged Tg2576 mice.

Systemic and acquired immune responses in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized clinically by a progressive cognitive decline and dementia. AD brains are marked by amyloid plaques and neurofibrillary tangles, neuronal cell loss, and a prominent activation of glial cells, and innate immune responses. A growing number of studies in AD have also reported alterations in systemic immune responses including changes in lymphocyte and macrophage distribution and activation, the presence of autoantibodies, or abnormal cytokine production. Studies in animal models for AD support the notion that immune cells infiltrate the brain and may modulate the disease. Here we will review evidence for systemic alterations in immune responses and a role for acquired immunity in AD and discuss their potential contribution to the disease.

Polymorphisms in the interleukin 6 and transforming growth factor beta1 gene and risk of dementia. The Rotterdam Study

Inflammatory mechanisms are involved in the pathogenesis of dementia. Inflammatory cytokines, including interleukin-6 (IL-6) and transforming growth factor beta1 (TGFbeta1), have been found in association with Alzheimer pathology and there is evidence for direct involvement of these cytokines in formation of amyloid plaques. Polymorphisms in genes encoding for IL-6 and TGFbeta1 are associated with plasma levels of IL-6 and TGFbeta1. Studies examining the association between polymorphisms in these genes and dementia yielded conflicting results. The purpose of this study was to examine the association between genetic variance in IL-6 and TGFbeta1 and risk of dementia. We examined this association in the Rotterdam Study, a prospective population-based cohort study in the elderly. Polymorphisms in the IL-6 (-174G>C) and TGFbeta1 gene (-800G>A, -509C>T, +10T>C, +25G>C and 263C>T) were genotyped and haplotypes of the TGFbeta1 gene were constructed. In a random subset IL-6 plasma levels were measured. During follow-up (mean 9.2 years), 743 dementia cases were identified. We estimated the association between individual polymorphisms and haplotypes with dementia with Cox' proportional hazard models. No association was found between the -174G>C polymorphism in the IL-6 gene and risk of dementia. No association was found between polymorphisms and constructed haplotypes in the TGFbeta1 gene and risk of dementia or Alzheimer's disease. No association was found between IL-6 genotype and IL-6 plasma levels in the random subset. Associations did not differ across APOE genotypes. Our findings do not suggest involvement of genetic variance in IL-6 and TGFbeta1 in the development of dementia.

The immunopharmacological properties of transforming growth factor beta

Transforming growth factor-beta (TGF-beta) family members are multifunctional molecules, which play pivotal roles in regulating cell proliferation, differentiation, migration, development, tissue remodeling and repair. These events are closely associated with host immune responses and inflammation. Despite some controversies on their function in controlling dendritic and T regulatory cell development and activity, the importance of TGF-betas in the progress of autoimmunity and inflammatory diseases has been well appreciated and new aspects of their contribution continue to be recognized. Since one of the major biological properties of TGF-betas is its capacity to potently suppress immune responses, they are considered as candidates for the development of therapeutic agents to fend off undesirable damage associated with immune and inflammatory conditions.

Sp1 and Smad transcription factors co-operate to mediate TGF-beta-dependent activation of amyloid-beta precursor protein gene transcription

Abnormal deposition of Abeta (amyloid-beta peptide) is one of the hallmarks of AD (Alzheimer's disease). This peptide results from the processing and cleavage of its precursor protein, APP (amyloid-beta precursor protein). We have demonstrated previously that TGF-beta (transforming growth factor-beta), which is overexpressed in AD patients, is capable of enhancing the synthesis of APP by astrocytes by a transcriptional mechanism leading to the accumulation of Abeta. In the present study, we aimed at further characterization of the molecular mechanisms sustaining this TGF-beta-dependent transcriptional activity. We report the following findings: first, TGF-beta is capable of inducing the transcriptional activity of a reporter gene construct corresponding to the +54/+74 region of the APP promoter, named APP(TRE) (APP TGF-beta-responsive element); secondly, although this effect is mediated by a transduction pathway involving Smad3 (signalling mother against decapentaplegic peptide 3) and Smad4, Smad2 or other Smads failed to induce the activity of APP(TRE). We also observed that the APP(TRE) sequence not only responds to the Smad3 transcription factor, but also the Sp1 (signal protein 1) transcription factor co-operates with Smads to potentiate the TGF-beta-dependent activation of APP. TGF-beta signalling induces the formation of nuclear complexes composed of Sp1, Smad3 and Smad4. Overall, the present study gives new insights for a better understanding of the fine molecular mechanisms occurring at the transcriptional level and regulating TGF-beta-dependent transcription. In the context of AD, our results provide additional evidence for a key role for TGF-beta in the regulation of Abeta production.

Biomarkers of Alzheimer disease in plasma

Plasma and serum biochemical markers proposed for Alzheimer disease (AD) are based on pathophysiologic processes such as amyloid plaque formation [amyloid beta-protein (A beta), A beta autoantibodies, platelet amyloid precursor protein (APP) isoforms], inflammation (cytokines), oxidative stress (vitamin E, isoprostanes), lipid metabolism (apolipoprotein E, 24S-hydroxycholesterol), and vascular disease [homocysteine, lipoprotein (a)]. Most proteins or metabolites evaluated in plasma or serum thus far are, at best, biological correlates of AD: levels are statistically different in AD versus controls in some cohorts, but they lack sensitivity or specificity for diagnosis or for tracking response to therapy. Approaches combining panels of existing biomarkers or surveying the range of proteins in plasma (proteomics) show promise for discovering biomarker profiles that are characteristic of AD, yet distinct from nondemented patients or patients with other forms of dementia.

Neuroinflammation and anti-inflammatory therapy for Alzheimer's disease

Neuroinflammation is now recognized as a prominent feature in Alzheimer's pathology and a potential target for therapy aimed at treatment and prevention of disease. This review provides a synopsis of current information about cellular and molecular mediators involved in Alzheimer's neuroinflammation as well as interactions between these mediators that influence pathology. Anti-inflammatory therapies, particularly nonsteroidal anti-inflammatory drugs, are considered from experimental and clinical perspectives and potential mechanisms underlying their apparent benefits are discussed. Finally, possible protective effects of the inflammatory response in Alzheimer's are described. Taken all together, evidence presented in this review suggests a scheme for Alzheimer's pathogenesis, with neuroinflammation playing a crucial role influencing and linking beta-amyloid deposition to neuronal damage and clinical disease.

Transforming growth factor-Beta 1 (tgf-Beta 1) in patients with amyotrophic lateral sclerosis

Previous investigations have shown that the transforming growth factor-beta 1 (TGF-beta 1) may protect neurons against excitotoxic and oxidative damage and may inhibit apoptosis. The aim of this study was to investigate the role of TGF-beta 1 in patients with amyotrophic lateral sclerosis (ALS). The study involved 24 ALS patients and 15 control group people. The ALS patients were divided into groups according to their clinical status, and duration of ALS. The TGF-beta 1 in the serum and cerebrospinal fluid (CSF) was measured by the enzyme-linked immunosorbent assay (ELISA). Results showed that TGF-beta 1 concentrations in the serum, and CSF in the whole group of ALS patients did not differ from those of the controls, but the serum TGF-beta 1 concentration was significantly higher in ALS patients with a terminal clinical status than in controls. The TGF-beta 1 concentration was significantly higher in the CSF of the patients, with a long duration of ALS, than in the patients with a short duration of ALS, and there was a significant positive correlation between the CSF TGF-beta 1 and the duration of ALS. TGF-beta 1 may play a role in neurodegeneration of ALS, and may be an indicator of the duration of the disease.

Molecular and functional dissection of TGF-beta1-induced cerebrovascular abnormalities in transgenic mice

Cerebrovascular abnormalities, such as reduced blood flow, microvascular fibrosis, and cerebrovascular amyloid angiopathy, are prominent in Alzheimer's disease (AD). However, their etiology is poorly understood and it is unclear whether cerebrovascular changes contribute to functional impairments in the absence of neurodegeneration. In humans with AD, transforming growth factor-beta1 (TGF-beta1) mRNA levels in the midfrontal gyrus correlate positively with the relative degree of cerebrovascular amyloid deposition in that brain region, suggesting a possible role for TGF-beta1 in human cerebrovascular abnormalities. Transgenic mice overexpressing TGF-beta1 in astrocytes develop AD-like cerebrovascular abnormalities, including perivascular astrocytosis, microvascular basement membrane thickening, and accumulation of thioflavin S-positive amyloid in the absence of parenchymal degeneration. Mice overexpressing TGF-beta1 alone or in addition to human amyloid precursor protein (hAPP) show selective accumulation of human beta-amyloid (Abeta) in blood vessels and develop cerebral hemorrhages in old age. In 9-month-old TGF-beta1 transgenic mice, cerebral blood flow (CBF) in the limbic system was significantly less than in nontransgenic littermate controls. Aged TGF-beta1 mice also showed overall reduced cerebral glucose uptake (CGU) as a measure of brain activity. Thus, chronic overproduction of TGF-beta1 in the brain results in structural and functional impairments reminiscent of those in AD cases with amyloid angiopathy.

Increased plasma TGF-beta1 in patients with amyotrophic lateral sclerosis

OBJECTIVES

To investigate the levels of transforming growth factor-beta1 (TGF-beta1) in plasma of patients with amyotrophic lateral sclerosis (ALS).

MATERIAL AND METHODS

The TGF-beta1 plasma concentrations were measured with an enzyme-linked immunosorbent assay from 11 patients with ALS and 13 age matched healthy controls.

RESULTS

The mean TGF-beta1 plasma concentration in the patients with ALS (2.15 +/- 0.80 ng/ml, mean +/- SD) was significantly higher than in the healthy controls (1.59 +/- 0.32 ng/ml) (P=0.031). There was a significant positive correlation between the TGF-beta1 plasma concentration in the patients with ALS and the duration of illness (r=0.66, P=0.028).

CONCLUSION

Our findings provide evidence that in ALS the plasma concentration of TGF-beta1 increases significantly with the duration of illness. These results suggest that TGF-beta1 is involved in the disease process of ALS.

Biochemical markers related to Alzheimer's dementia in serum and cerebrospinal fluid

The diagnosis of Alzheimer's disease (AD) is currently based on clinical and neuropsychological examination. To date there is no blood test available that can discriminate dementia patients from healthy individuals. In the present paper, an overview of the current state of knowledge on biologic markers in serum (plasma) and CSF is presented. The combination of characteristic plaque markers tau and amyloid bèta may constitute a specific and sensitive CSF marker for AD. Glial fibrillary acidic protein and antibodies in CSF may be a marker for severe neurodegeneration. CSF concentrations of the oxidative stress markers 3-nitrotyrosine, 8-hydroxy-2'-deoxyguanosine and isoprostanes are increased in AD patients. Serum 24S-OH-cholesterol may be an early whereas glial fibrillary acidic protein autoantibody level may be a late marker for neurodegeneration. To date, serum alpha(1)-Antichymotripsin concentration is the most convincing marker for CNS inflammation. Increased serum homocysteine concentrations have also been consistently reported in AD. In summary, a large overlap in mean concentrations has been observed in studies comparing AD patients with healthy controls for single markers. These studies together support the theory of testing several serum markers in combination for the diagnosis of AD.

Decrease of TGF-beta1 plasma levels and increase of nitric oxide synthase activity in leukocytes as potential biomarkers of Alzheimer's disease

A variety of inflammatory proteins have been identified in brains of Alzheimer's disease (AD) patients, including inflammatory cytokines, acute phase proteins and complement components. In the present paper we have investigated the levels of circulating inflammatory mediators as potential biomarkers of this disease, concentrating mostly on transforming growth factor beta (TGF-beta1) in plasma and on nitric oxide synthase (NOS) activity in leukocytes. Plasma and leukocytes were isolated from 48 sporadic AD and 23 healthy control subjects of same age and sex. Since alpha2-Macroglobulin (alpha2M), an acute phase protein possibly involved in AD, is an important modulator of TGF-beta1 activity, binding and targeting this cytokine to its appropriate site of action, we have investigated the possible complex between TGF-beta1 and alpha2M in plasma of the same subjects. The results demonstrate a significant reduction of TGF-beta1 levels in plasma of AD patients. A complex between alpha2M and TGF-beta1 occurred in AD as well as healthy elderly control subjects, however, with no significant differences. Moreover, alpha2M appeared to bind only the inactive form of this cytokine. In contrast, NOS activity increased significantly in leukocytes of AD patients. Therefore, we suggest the combined determination of TGF-beta1 in the plasma and of NOS activity in the leukocytes as biomarkers of AD.

Functional role of TGF beta in Alzheimer's disease microvascular injury: lessons from transgenic mice

Recent studies have implicated pro- and anti-inflammatory cytokines as integral to Alzheimer's disease (AD) pathogenesis. Among them, transforming growth factor-beta (TGF-beta) is emerging as an important factor in regulating inflammatory responses. This multifunctional cytokine might be centrally involved in several aspects of AD pathogenesis by regulating beta-amyloid precursor protein synthesis and processing, plaque formation, astroglial and microglial response and neuronal cell death. Among all of these potential roles, studies in transgenic and infusion animal models have shown that TGF-beta may primarily contribute to AD pathogenesis by influencing A beta production and deposition, which in turn might result in damage to the brain microvasculature. The lessons learned from these models are of great interest not only for understanding of the role of TGF-beta in AD, but also for future treatments where testing of anti-inflammatory agents such as ibuprofen and an amyloid vaccine hold great promise. In this regard, further elucidation of the signal pathways by which TGF-beta exerts its effect in AD might lead to specific targets for further therapeutic intervention.