Molecular Mechanisms Linking Osteoarthritis and Alzheimer's Disease: Shared Pathways, Mechanisms and Breakthrough Prospects.

Alzheimer's disease (AD) is a progressive neurodegenerative disease mostly affecting the elderly population. It is characterized by cognitive decline that occurs due to impaired neurotransmission and neuronal death. Even though deposition of amyloid beta (Aß) peptides and aggregation of hyperphosphorylated TAU have been established as major pathological hallmarks of the disease, other factors such as the interaction of genetic and environmental factors are believed to contribute to the development and progression of AD. In general, patients initially present mild forgetfulness and difficulty in forming new memories. As it progresses, there are significant impairments in problem solving, social interaction, speech and overall cognitive function of the affected individual. Osteoarthritis (OA) is the most recurrent form of arthritis and widely acknowledged as a whole-joint disease, distinguished by progressive degeneration and erosion of joint cartilage accompanying synovitis and subchondral bone changes that can prompt peripheral inflammatory responses. Also predominantly affecting the elderly, OA frequently embroils weight-bearing joints such as the knees, spine and hips leading to pains, stiffness and diminished joint mobility, which in turn significantly impacts the patient's standard of life. Both infirmities can co-occur in older adults as a result of independent factors, as multiple health conditions are common in old age. Additionally, risk factors such as genetics, lifestyle changes, age and chronic inflammation may contribute to both conditions in some individuals. Besides localized peripheral low-grade inflammation, it is notable that low-grade systemic inflammation prompted by OA can play a role in AD pathogenesis. Studies have explored relationships between systemic inflammatory-associated diseases like obesity, hypertension, dyslipidemia, diabetes mellitus and AD. Given that AD is the most common form of dementia and shares similar risk factors with OA-both being age-related and low-grade inflammatory-associated diseases, OA may indeed serve as a risk factor for AD. This work aims to review literature on molecular mechanisms linking OA and AD pathologies, and explore potential connections between these conditions alongside future prospects and innovative treatments.

Evaluation of New Potential Inflammatory Markers in Patients with Nonvalvular Atrial Fibrillation.

Atrial fibrillation (AF), the most common arrhythmia in clinical practice, is associated with an increase in mortality and morbidity due to its high potential to cause stroke and systemic thromboembolism. Inflammatory mechanisms may play a role in the pathogenesis of AF and its maintenance. We aimed to evaluate a range of inflammatory markers as potentially involved in the pathophysiology of individuals with nonvalvular AF (NVAF). A total of 105 subjects were enrolled and divided into two groups: patients with NVAF (n = 55, mean age 72 ± 8 years) and a control group of individuals in sinus rhythm (n = 50, mean age 71 ± 8 years). Inflammatory-related mediators were quantified in plasma samples by using Cytometric Bead Array and Multiplex immunoassay. Subjects with NVAF presented significantly elevated values of interleukin (IL)-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF), interferon-gamma, growth differentiation factor-15, myeloperoxidase, as well as IL-4, interferon-gamma-induced protein (IP-10), monokine induced by interferon-gamma, neutrophil gelatinase-associated lipocalin, and serum amyloid A in comparison with controls. However, after multivariate regression analysis adjusting for confounding factors, only IL-6, IL-10, TNF, and IP-10 remained significantly associated with AF. We provided a basis for the study of inflammatory markers whose association with AF has not been addressed before, such as IP-10, in addition to supporting evidence about molecules that had previously been associated with the disease. We expect to contribute to the discovery of markers that can be implemented in clinical practice hereafter.

Evaluation of serum haptoglobin levels and Hp1-Hp2 polymorphism in the haptoglobin gene in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is an arrhythmia that involves structural and electrophysiological abnormalities. Many of the AF-related clinical conditions are associated with an increase in inflammatory and oxidative factors. Haptoglobin (Hp) is an acute phase protein whose biological role is to promote clearance of free hemoglobin (Hb). In addition, for being considered an inflammatory marker, Hp represents a protective mechanism against the oxidative effects of Hb. The Hp1-Hp2 polymorphism at Hp locus can lead to three phenotypes related to structural and functional differences in the protein. The objective of this study were to evaluate Hp levels and Hp1-Hp2 polymorphism at Hp locus in patients with AF compared to a control group. METHODS AND RESULTS: This study included 65 patients with AF and 54 individuals without the arrhythmia. Biochemical parameters were determined using Vitros system, plasma levels of Hp were measured in serum samples by using ELISA method and polymorphisms were verified by PCR technique. Plasma Hp levels, as well as allelic and genotypic frequency, were not associated with AF. The levels of Hp also did not differ among the genotypes according to the applied models. CONCLUSIONS: The results suggest that Hp levels and Hp1-Hp2 polymorphism are not associated to AF.

Thrombin Generation and other hemostatic parameters in patients with atrial fibrillation in use of warfarin or rivaroxaban.

Patients with atrial fibrillation (AF) present hyperactivation of both platelets and coagulation leading to a hypercoagulable state which contributes to an increased risk of thromboembolism. Therefore, one of the main strategies for treatment of AF is prevention of these events through the use of oral anticoagulants (OAC). The aim of this study was to evaluate hemostasis as a whole in patients with non-valvular AF undergoing warfarin or rivaroxaban by thrombin generation test (TGT), in addition to monocyte-platelet aggregates (MPA), glycoprotein IIb/IIIa (GPIIb/IIIa), and platelet (PMP) and endothelium (EMP) microparticles, compared to age and sex matched controls. PT/INR for OAC use was also determined. In patients taking OAC, compared to control group, a decrease in TGT (p = 0.000 for all parameters) were observed. Patients taking warfarin showed to be more hypocoagulable, presenting lower levels of ETP (p = 0.000) and peak (p = 0.002) than patients using rivaroxaban. Patients on warfarin use with INR > 3 had also lower levels of ETP (p = 0.01) and peak (p = 0.006). A decrease in ETP (p = 0.03) and peak (p = 0.02) values was also observed in patients using rivaroxaban with PT > 21.4 s. Patients using warfarin (p = 0.000) and rivaroxaban (p = 0.000) presented lower levels of MPA in relation to control group. It was also observed in patients using warfarin, lower GPIIb/IIIa levels in relation to control group (p = 0.011). Patients taking rivaroxaban (p = 0.003) and warfarin (p = 0.001) had higher PMP levels compared to control group. There was no difference in levels of EMP between the groups (p = 0.0536). The present study reinforces the usefulness of OAC in AF, which decisively contribute to a better management of the disease preventing possible complications.

Evaluation of Brain Cytokines and the Level of Brain-Derived Neurotrophic Factor in an Inflammatory Model of Depression.

INTRODUCTION: Major depressive disorder is considered a global public health problem. Inflammatory processes are likely involved in its pathophysiology, but the underlying mechanisms have remained uncertain.Here, we used the model of systemic lipopolysaccharide (LPS) injection to test the hypothesis that depressive-like behaviors occur along with changes in the levels of cytokines and brain-derived neurotrophic factor (BDNF) in the hippocampus (HC), prefrontal cortex (PFC), and hypothalamus (HT), and can be prevented by dexamethasone administration. METHODS: Adult C57Bl/6 male mice were first isolated for 10 days, and thereafter received an injection of dexamethasone (6 mg/kg, intraperitoneal [i.p.]), saline followed by LPS (0.83 mg/kg, i.p.), or saline. After 6 h, animals were subjected to the forced-swim test (FST) and open-field tests. Immediately after the behavioral tests, they were euthanized and their brains were collected for the biochemical analyses. RESULTS: LPS increased the immobility time and reduced the distance travelled in the FST and open-field test, respectively. Dexamethasone increased the immobility time in saline-treated mice but reduced this behavior in the LPS group. LPS increased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interferon (IFN)-γ in most of the regions evaluated. Dexamethasone prevented LPS-induced IL-6 in the HC, PFC, and HT. Interestingly, dexamethasone increased IL-4 and IL-10 levels in both the LPS- and saline-treated groups. Although dexamethasone reduced BDNF in saline-treated mice, it prevented LPS-induced reduction in this neurotrophic factor. CONCLUSION: In summary, dexamethasone decreased proinflammatory and increased anti-inflammatory levels of cytokines and prevented a reduction in BDNF levels induced by the inflammatory stimulus. Thus, the attenuation of depressive-like behavior induced by dexamethasone may be related to the effects on these parameters.

Inflammatory and Infectious Processes Serve as Links between Atrial Fibrillation and Alzheimer's Disease.

Atrial fibrillation (AF) is one of the most prevalent forms of arrhythmia that carries an increased risk of stroke which, in turn, is strongly associated with cognitive decline. The majority of dementia cases are caused by Alzheimer's disease (AD) with obscure pathogenesis. While the exact mechanisms are unknown, the role of inflammatory processes and infectious agents have recently been implicated in both AD and AF, suggesting a common link between these maladies. Here, we present the main shared pathways underlying arrhythmia and memory loss. The overlapping predictive biomarkers and emerging joint pharmacological approaches are also discussed.

Plasma levels of soluble tumor necrosis factor receptors are associated with cognitive performance in Parkinson's disease.

Inflammatory mechanisms have been implicated in a series of neuropsychiatric conditions, including behavioral disturbances, cognitive dysfunction, and affective disorders. Accumulating evidence also strongly suggests their involvement in the pathophysiology of Parkinson's disease (PD). This study aimed to evaluate plasma levels of inflammatory biomarkers, and their association with cognitive performance and other non-motor symptoms of PD. PD patients and control individuals were subjected to various psychometric tests, including the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Beck's Depression Inventory (BDI). Biomarker plasma levels were measured by enzyme-linked immunosorbent assay (ELISA). PD patients exhibited worse performance on MMSE and the programming task of FAB, and presented higher soluble tumor necrosis factor receptor (sTNFR) plasma levels than control individuals. Among PD patients, increased sTNFR1 and sTNFR2 concentrations were associated with poorer cognitive test scores. After multiple linear regression, sTNFR1 and education remained a significant predictor for FAB scores. Our data suggest that PD is associated with a proinflammatory profile, and sTNFRs are putative biomarkers of cognitive performance, with elevated sTNFR1 levels predicting poorer executive functioning in PD patients.

Depression and cognitive impairment in Parkinson's disease: a role for inflammation and immunomodulation?

The etiology of Parkinson's disease (PD) is complex and not fully understood, most probably because of the multiplicity of factors involved. Inflammatory and abnormal immune responses have been hypothesized to play a crucial role in PD. Not only in the brain, but also peripherally, inflammation is believed to contribute to the onset and progression of the neurodegenerative process seen in PD. Furthermore, increased inflammatory responses have been described both in the brain and peripheral blood of PD subjects. Although PD is considered a motor disorder, nonmotor symptoms are extremely frequent and disabling. Cognitive impairment and mood alterations are such symptoms that deserve increased attention since on the one hand they can appear even before typical motor disturbances are recognized, and on the other hand they are associated with high morbidity and mortality. A growing body of evidence suggests the existence of a link between inflammatory-immune responses and the occurrence of depression and cognitive impairment in PD patients. However, not all data are equally conclusive and are sometimes even conflicting. The aim of this brief review is to give an overview of the possible role that inflammation and immunomodulation may play in PD together with their putative impact on mood and cognitive alterations. What clearly emerges from this work is the fact that studies performed until now lack standardized and comparable methods to analyze both clinical and biological parameters. It is thus difficult to conclusively link mood and cognitive changes to underlying pathological mechanisms. Additional studies in this direction are warranted to convincingly establish or refute any causative relation.

Chemokines in bipolar disorder: trait or state?

Recent evidence has suggested that inflammatory and immune mechanisms may play a role in the pathophysiology of bipolar disorder (BD). Only a few studies have assessed the profile of chemokines, a family of chemotactic cytokines related to the recruitment of leukocytes, in BD. The objective of our study was to evaluate the plasma levels of chemokines in BD patients in different mood states in comparison with healthy controls. Seventy BD type I patients (35 in euthymia and 35 in mania), and 50 healthy controls matched by age, gender, and education level were enrolled in this study. All subjects were assessed by the Mini-International Neuropsychiatry Interview and the patients by the Young Mania Rating Scale and the Hamilton Depression Rating Scale. The plasma levels of CCL2, CCL3, CCL11, CCL24, CXCL8, and CXCL10 were measured by enzyme-linked immunosorbent assay. BD patients presented higher plasma levels of CCL11 (1.69-fold increase; p < 0.001), CCL24 (1.40-fold increase; p = 0.02), CXCL10 (1.45-fold increase; p < 0.001) and decreased plasma levels of CXCL8 (8.68-fold decrease p < 0.001). Logistic regression stressed the main effect of increased plasma levels of CXCL10 (OR = 1.009, 95 % CI = 1.000-1.018, p = 0.042) and CCL11 (OR = 1.002, 95 % CI = 1.001-1.003, p = 0.003) and decreased plasma levels of CXCL8 (OR = 0.995, 95 % CI = 0.990-0.999, p = 0.013) to BD. This study reinforces the view that BD is associated with an immune dysfunction.

Peripheral blood mono-nuclear cells derived from Alzheimer's disease patients show elevated baseline levels of secreted cytokines but resist stimulation with ß-amyloid peptide.

OBJECTIVES: Among several other factors, the neuro-toxic ß-amyloid peptide (ßAP)-induced inflammatory mechanisms have also been implicated in the pathogenesis of Alzheimer's dementia (AD). Cytokines have recently emerged as prime candidates underlying this immune reaction. The purpose of this study was to evaluate the inflammatory response of peripheral blood mono-nuclear cells (PBMC) in AD. DESIGN: Cross-sectional (observational) study. SETTING: Behavioral and cognitive neurology clinic of the Universidade Federal de Minas Gerais in Belo Horizonte, Brazil. PARTICIPANTS: AD patients (n=19), healthy elderly (n=19) and young (n=14) individuals. MEASUREMENTS: Cytokine levels were assessed by enzyme-linked immuno-sorbent assay (ELISA) after exposing cells to a broad range of ßAP concentrations (10(-4)-10(-10)M) as a stimulus. AD samples were weighed against leukocytes harvested from non-demented young and elderly subjects. RESULTS: Cytokine production of PBMCs in the youth was characterized by low baseline levels when compared to cells from the older generation. In the aging population, AD cells were distinguished from the healthy elderly sub-group by an even higher basal cytokine secretion. The low resting concentration in young individuals was markedly increased after treatment with ßAP, however cells from the elderly, irrespective of their disease status, showed unchanged cytokine release following ßAP administration. Non-specific activation of PBMCs with anti-CD3/CD28 antibodies resulted in elevated interleukin (IL)-1ß concentrations in AD. CONCLUSIONS: These results demonstrate a general over-production of cytokines and resistance to ßAP in the old comparison group, with a more pronounced disruption/boosted pattern in AD. Our findings are in line with the hypothesis of "inflammaging", i.e. an enhanced inflammatory profile with normal aging and a further perturbed environment in AD. The observed cytokine profiles may serve as diagnostic biomarkers in dementia.

Serotonin and dopamine receptors profile on peripheral immune cells from patients with temporal lobe epilepsy.

The role of inflammation and immune cells has been demonstrated in neurological diseases, including epilepsy. Leukocytes, as well as inflammatory mediators, contribute to abnormal processes that lead to a reduction in seizure threshold and synaptic reorganization. In this sense, identifying different phenotypes of circulating immune cells is essential to understanding the role of these cells in epilepsy. Immune cells can express a variety of surface markers, including neurotransmitter receptors, such as serotonin and dopamine. Alteration in these receptors expression patterns may affect the level of inflammatory mediators and the pathophysiology of epilepsy. Therefore, in the current study, we evaluated the expression of dopamine and serotonin receptors on white blood cells from patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Blood samples from 17 patients with TLE-HS and 21 controls were collected. PBMC were isolated and stained ex vivo for flow cytometry. We evaluated the expression of serotonin (5-HT1A, 5-HT1B, 5-HT2, 5-HT2B, 5-HT2C, 5-HT3, 5-HT4), and dopamine receptors (D1, D2, D3, D4, and D5) on the cell surface of lymphocytes and innate immune cells (monocytes and granulocytes). Our results demonstrated that innate cells and lymphocytes from patients with TLE-HS showed high mean fluorescent intensity (MFI) for 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 compared to controls. No difference was observed for 5-HT2B. For dopamine receptors, the expression of D1, D2, D4, and D5 receptors was higher on innate cells from patients with TLE-HS when compared to controls for the MFI. Regarding lymphocytes population, D2 expression was increased in patients with TLE-HS. In conclusion, there are alterations in the expression of serotonin and dopamine receptors on immune blood cells of patients with TLE-HS. Although the biological significance of these findings still needs to be further investigated, these changes may contribute to the understanding of TLE-HS pathophysiology.

Cannabidiol prevents lipopolysaccharide-induced sickness behavior and alters cytokine and neurotrophic factor levels in the brain.

BACKGROUND: Major depressive disorder (MDD) affects millions of people worldwide. While the exact pathogenesis is yet to be elucidated, the role of neuro-immune signaling has recently emerged. Despite major advances in pharmacotherapy, antidepressant use is marred by limited efficacy and potential side effects. Cannabidiol (CBD), a phytocannabinoid, exerts antidepressant-like effects in experimental animals. This study investigated the impact of CBD on sickness behavior (SB), a measure of depressive-like response, and neuro-immune changes induced by lipopolysaccharides (LPS) in mice. METHODS: Socially isolated rodents were administered with LPS to trigger SB. and treated with CBD or its vehicle. Animals were submitted to forced swimming test, to evaluate depressive-like behavior, and to open field test, to evaluate locomotory activity. Immediately after behavioral analyses, animals were euthanized and had their hypothalamus, prefrontal cortex and hippocampus dissected, to proceed neurotrophins and cytokines analyses. ELISA was used to detect IL-1ß, BDNF and NGF; and cytometric beads array to measure IL-2, IL-4, IL-6, IFN-γ, TNF-α and IL-10 levels. RESULTS: CBD effectively prevented SB-induced changes in the forced swim test without altering spontaneous locomotion. This phytocannabinoid also partially reversed LPS-evoked IL-6 increase in both the hypothalamus and hippocampus. In addition, CBD prevented endotoxin-induced increase in BDNF and NGF levels in the hippocampus of SB animals. CONCLUSIONS: Apparently, CBD prevents both behavioral and neuro-immunological changes associated with LPS-induced SB, which reinforces its potential use as an antidepressant which modulates neuroinflammation. This opens up potentially new therapeutic avenues in MDD.

Comparison of Inflammatory Mediators in Patients With Atrial Fibrillation Using Warfarin or Rivaroxaban.

Background: Atrial fibrillation (AF) is the most common arrhythmia associated with high risk of venous thromboembolism. Inflammatory mechanisms may be involved in the pathophysiology of AF and in the AF-related thrombogenesis, and patients with AF might benefit from the use of anticoagulants with anti-inflammatory properties. However, the evidence is still scarce, and it points out the need of trials seeking to investigate the levels of inflammatory mediators in patients with AF under different anticoagulant therapies. Therefore, this study was designed to define whether patients with AF treated either with an activated coagulation factor X (FXa) inhibitor (rivaroxaban) or with a vitamin K inhibitor (warfarin) present changes in peripheral levels of inflammatory mediators, mainly cytokines and chemokines. Methods: A total of 127 subjects were included in this study, divided into three groups: patients with non-valvular atrial fibrillation (NVAF) using warfarin (N = 42), patients with NVAF using rivaroxaban (N = 29), and controls (N = 56). Plasma levels of inflammatory mediators were quantified by immunoassays. Results: Patients with AF (both warfarin and rivaroxaban groups) presented increased levels of inflammatory cytokines in comparison with controls. The use of rivaroxaban was associated with decreased levels of inflammatory cytokines in comparison with warfarin. On the other hand, patients with AF using rivaroxaban presented increased levels of the chemokines (MCP-1 in comparison with warfarin users; MIG and IP-10 in comparison with controls). Conclusions: AF is associated with an inflammatory profile that was less pronounced in patients on rivaroxaban in comparison with warfarin users. Further studies are necessary to assess the clinical implications of our results and whether patients with AF would benefit from rivaroxaban anti-inflammatory effects.

Increased serum levels of brain-derived neurotrophic factor in chronic institutionalized patients with schizophrenia.

There is a growing body of evidence implicating the neurotrophin brain-derived neurotrophic factor (BDNF) in the pathogenesis of schizophrenia. As circulating BDNF levels may reflect the BDNF levels in the brain, we assessed serum BDNF in 40 institutionalized schizophrenic patients and 20 healthy controls. Serum BNDF levels were significantly increased in schizophrenic patients when compared to control subjects (p<0.001). Interestingly, serum BDNF correlated positively with the clinical scores at the negative subscale of the positive and negative syndrome scale (PANSS) (r=0.41; p<0.01). Our results confirm the emergent literature on the involvement of BDNF in schizophrenia.

Increased serum levels of CCL11/eotaxin in schizophrenia.

BACKGROUND: Inflammatory and immune alterations occur and may be relevant in patients with schizophrenia. Chemokines are a subgroup of cytokines that play a major role in the recruitment of determined subsets of leukocytes into tissues. To date no study has evaluated whether levels of chemokines are altered in patients with schizophrenia. OBJECTIVE: To evaluate serum levels of CC and CXC chemokines of schizophrenic patients and age- and gender-matched controls. METHODS: Forty male institutionalized schizophrenic patients (mean+/-SD age, 52.3+/-9.9) and 20 asymptomatic matched controls were recruited for this study. Severity of symptoms was assessed using BPRS, PANSS and AIMS. All patients were under typical antipsychotic treatment. Serum concentrations of chemokines were measured by ELISA. RESULTS: There was no statistical difference in serum levels of CCL2, CCL3, CCL24, CXCL9 and CXCL10 between controls and patients. Serum levels of CCL11 were increased in schizophrenic patients when compared to controls. Serum levels of chemokines were not correlated with the length of disease or hospitalization and the severity of involuntary movements, positive and/or negative symptoms. CONCLUSION: CCL11 is a ligand for CCR3, a receptor expressed preferentially on Th2 lymphocytes, mast cells and eosinophils. Higher serum levels of CCL11 in schizophrenia reinforce the view that this disease may be associated with a Th1/Th2 imbalance with a shift toward a Th2 immune response.

Increased serum levels of inflammatory markers in chronic institutionalized patients with schizophrenia.

UNLABELLED: Activation of the cytokine systems may be involved in the neuropathological changes occurring in the central nervous systems of schizophrenic patients. However, associations between the levels of cytokines and the severity of symptoms have not been completely established. OBJECTIVE: It was the aim of this study to evaluate serum levels of tumor necrosis factor (TNF)-alpha and their soluble receptors (sTNFR) in schizophrenic patients and healthy controls. METHODS: Forty male institutionalized schizophrenic patients (mean age +/- SD, 52.3 +/- 9.9 years) and 20 asymptomatic matched controls were recruited. The severity of symptoms was assessed using the Brief Psychiatric Rating Scale, the Positive and Negative Syndrome Scale and the Abnormal Involuntary Movement Scale. Serum levels of cytokines were measured by ELISAs. RESULTS: Serum levels of sTNFR1 and sTNFR2 were increased in schizophrenic patients when compared with controls (all p < 0.05), but there was no difference in TNF-alpha levels. There was no correlation between the length of disease/hospitalization or the severity of symptoms and the serum levels of these molecules. CONCLUSION: Inflammatory markers are increased in schizophrenia but they do not correlate with symptom severity.

Inflammation as a Possible Link Between Dyslipidemia and Alzheimer's Disease.

Alzheimer's disease (AD) is the leading cause of dementia worldwide. This pathological condition is characterized not only by Aß and tau accumulation in the central nervous system (CNS), but also by inflammation, processes that can lead to neurodegeneration. Besides that, other factors may contribute to the development of AD, such as dyslipidemias. Changes in lipid levels can either influence the activity of enzymes related to the protein deposition that occurs in this pathological condition, or enhance the peripheral and CNS immune responses. Furthermore, cholesterol-associated genes are frequently associated with AD. Here, we extensively reviewed the literature and, based on the existing evidences, we suggest inflammation as an important link between dyslipidemias and AD.

Reduced Activated T Lymphocytes (CD4+CD25+) and Plasma Levels of Cytokines in Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease. The cause of neurodegeneration in PD is not completely understood, and evidence has shown that inflammatory/immune changes may be involved in PD pathophysiology. Herein, we aimed to determine the profile of the peripheral immune system in patients with PD in comparison with controls. Forty patients with PD and 25 age- and gender-matched controls were enrolled in this study. From these, 23 PD patients and 21 controls were included in the immunophenotyping analyses. Peripheral blood was drawn on the same day of the clinical assessment and submitted to plasma separation for enzyme-linked immunosorbent assay or cytometric bead array. Immunophenotyping analyses of the peripheral blood were performed by flow cytometry. We found that patients with PD presented peripheral immune changes evidenced by decreased percentage of T lymphocytes (CD3+ cells), especially activated T lymphocytes (CD4+CD25+ cells), when compared with controls. In line with these results, we also found decreased plasma levels of the cytokines IL-4, IL-6, IL-10, TNF, IFN-γ, and IL-17A in the PD group. In vitro experiments demonstrated that the production of cytokines by peripheral blood mononuclear cells harvested from healthy young donors was reduced after exposure to the anti-parkinsonian drugs levodopa and pramipexole. Our data corroborate the hypothesis that immunological mechanisms are involved in PD. It is not clear whether the differences that we have found are due to adaptive mechanisms or to changes associated with PD, including pharmacological treatment, or even directly related to the disease pathophysiology. Future studies are needed in this regard.

Circulating levels of neurotrophic factors are unchanged in patients with Parkinson's disease.

There is great evidence linking neurotrophic factor (NF) dysfunction with Parkinson's disease (PD) pathophysiology. This study was conducted to evaluate plasma levels of NFs and their possible associations with clinical symptoms in PD. For this purpose, 40 PD patients and 25 controls were subjected to a clinical evaluation and peripheral blood draw. Plasma levels of brain-derived neurotrophic factor (BDNF), pro-BDNF, neurotrophin 3, neurotrophin 4, nerve growth, glial cell line-derived neurotrophic factor and ciliary neurotrophic factor were measured by enzyme-linked immunosorbent assay. There was no significant difference between PD patients and controls regarding the plasma levels of the evaluated NFs. In addition, NF levels were not associated with disease duration, degree of motor or functional impairment, cognitive performance or severity of depressive symptoms. In conclusion, although NFs may play relevant roles in the pathophysiology of PD, the circulating levels of these molecules are not necessarily changed in patients with PD.

Thrombin generation assays for global evaluation of the hemostatic system: perspectives and limitations.

The existing techniques to evaluate hemostasis in clinical laboratories are not sensitive enough to detect hypercoagulable and mild hypocoagulable states. Under different experimental conditions, the thrombin generation test may meet these requirements. This technique evaluates the overall balance between procoagulant and anticoagulant forces and has provided new insights in our understanding of the coagulation cascade, as well as of the diagnosis of hypocoagulability and hypercoagulability conditions. Thrombin generated in the thrombin generation test can be quantified as platelet-rich or platelet-poor plasma using the calibrated automated thrombogram method, which monitors the cleavage of a fluorogenic substrate that is simultaneously compared to the known thrombin activity in a non-clotting plasma sample. The calibrated automated thrombogram method is an open system, in which different antibodies, proteins, enzymes and peptides can be introduced to answer specific questions regarding hemostatic processes. The thrombin generation test has great clinical potential, such as in monitoring patients taking anticoagulants and antiplatelet drugs, screening for genetic or acquired thrombotic disorders, and evaluating bleeding risk control in patients with hemophilia using bypass agents or replacement therapy. Different to conventional coagulation tests, the thrombin generation test can be used for an overall evaluation of hemostasis, the results of which can then be used to evaluate specific characteristics of hemostasis, such as prothrombin time, activated partial thromboplastin time, and levels of fibrinogen and other coagulation factors. The introduction of this method will contribute to a better understanding and evaluation of overall hemostatic processes; however, this method still requires standardization and clinical validation.