Association of interleukin-10 polymorphisms with risk factors of Alzheimer's disease and other dementias (SADEM study)

Feeding crocin ameliorate cognitive dysfunction, oxidative stress and neuroinflammation induced by unpredictable chronic mild stress in rats

INTRODUCTION

The aim of the current study was to investigate the probable mechanism and effect of crocin on brain oxidative damage and memory deficits induced by unpredictable chronic mild stress (UCMS).

MATERIALS AND METHODS

Male Wistar rats were randomly divided into six groups consisting of one vehicle group (received normal saline), four groups included rats who received UCMS 4 weeks out of which three groups were pretreated with different doses of crocin (10, 20, and 30 mg/kg/day) concomitantly. To assess the pure effect of crocin, the last experimental group received a high dose of crocin (30 mg/kg/day) without exposure to the UCMS procedure. The behavioral tests including Morris water maze (MWM) and passive avoidance (PA) were performed and eventually they were sacrificed for the estimation of biochemical parameters.

RESULTS

The increase in Malondialdehyde (MDA) as an oxidative stress indicator and nitrite levels in the hippocampus were observed in UCMS rats, along with memory deficits in behavioral tests including passive avoidance and Morris water maze (MWM) test. Moreover, treatment with crocin decreased MDA, nitrite, pro-inflammatory cytokine such as TNF-α, and pathological hallmark of Alzheimer's disease including amyloid-β (Aβ), and glial fibrillary acidic protein (GFAP) in the hippocampus, whereas antioxidant agents including total thiol content, SOD, and catalase activity were increased. Also behavioral test demonstrated a positive effect of crocin on memory deficit induced by UCMS. Interlukin-10 as an important anti-inflammatory agent was increased as well. Interestingly, in some behavioral and biochemical findings, treatment with 30 mg/kg of crocin has given better results compared to vehicle group, which means the administration of crocin could have preventive effects on learning and memory impairment.

CONCLUSION

The present study strongly confirmed the positive effect of crocin and has the potential as an antioxidant and anti-inflammatory agent that could improve memory impairment induced by UCMS.

Multifactor Dimensionality Reduction Analysis to Evaluate the Association of Dopamine Beta-Hydroxylase (DΒH) Polymorphisms with Susceptibility to Dementia (SADEM Study)

Dementia is a multifactorial disease in which environmental, lifestyle, and genetic factors intervene. Population studies have been used in looking for the susceptibility genes for this disease. Since the activity of dopamine b hydroxylase (DβH) is reduced in the hippocampus and neocortex in the brain, changes in the physiological status of dopamine have been reported in Alzheimer's disease (AD) induced by this enzyme. Therefore, DBH polymorphisms have been associated with susceptibility to some neurological diseases such as AD, but few studies have investigated the relationship between these polymorphisms with other types of dementia, especially in Mexican populations. The aim of this study was to evaluate the association between single-nucleotide polymorphism (SNP) in the dopamine b-hydroxylase (DBH gene (rs1611115) and their interactions with environmental factors and the dementia risk. We examined the genotype of the gene DBH (rs1611115) polymorphism in patients with dementia and healthy. The interaction and the impact of DBH (rs1611115) polymorphism on dementia were examined through multifactor dimensionality reduction (MDR) analysis, and the results were verified by the Chi-square test. Hardy-Weinberg equilibrium (HWE) was also checked by the Chi-square test. The relative risk was expressed by odds ratio (OR) and 95%. A total of 221 dementia patients and 534 controls met the inclusion criteria of MDR analyses. The results of the MDR analysis showed that the development of dementia was positively correlated with interaction between the TT genotype of the DBH1 locus rs1611115 TT and diabetes, hypertension, and alcohol consumption (OR = 6.5: 95% CI = 4.5-9.5), originating further cognitive damage. These findings provide insight into the positive correlation between the metabolism and cardiovascular disorders and the presence of the T allele by means of a recessive model of DBH rs1611115 polymorphism with the suspensibility of dementia.

Prevalence of dementia in Latin America and Caribbean countries: Systematic review and meta-analyses exploring age, sex, rurality, and education as possible determinants

BACKGROUND

Studies have shown that the prevalence of dementia in Latin America and the Caribbean (LAC) may be higher than in high-income countries. Thus, we sought to systematically analyse the prevalence of dementia and explore possible drivers that lead to this disparity in LAC countries.

METHOD

We searched Pubmed, Web of Knowledge, Scopus, Lilacs, and SciELO for studies on dementia in LAC countries published in English, Spanish, and Portuguese. Random-effects model was applied.

RESULTS

Thirty-one studies from 17 LAC countries were included. Pooled prevalence of all-cause dementia was 10.66%. Further analyses with studies providing raw prevalence by sex, area, and educational level showed a higher prevalence for women (8.97%) than for men (7.26%). Also, dementia prevalence was higher for rural than urban residents (7.71% vs 8.68%, respectively). Participants without formal education presented more than double the prevalence of dementia (21.37%) compared to those with at least one year of formal education (9.88%). Studies with more recent data collection showed higher dementia prevalence.

CONCLUSION

Our findings suggest a high global dementia prevalence in LAC countries and an unequal burden of dementia for women, lower-educated, and rural residents. Secular increases in dementia prevalence call for greater public health efforts for preventative actions.

Synergistic influence of cytokine gene polymorphisms over the risk of dementia: A multifactor dimensionality reduction analysis

OBJECTIVE

Evidence supports the important role of neuroinflammation in some types of dementia. This study aimed to evaluate the effect of epistasis of gene cytokines such as interleukin (IL)-α, IL-6, tumor necrosis factor (TNFα), and interferon-gamma (IFN-γ) on the susceptibility to the development of dementia.

MATERIALS AND METHODS

In the study, 221 patients diagnosed with dementia and 710 controls were included. The multifactor-dimensionality reduction (MDR) analysis was performed to identify the epistasis between SNP located in genes of IL-α (rs1800587), IL-6 (rs1800796), TNFα (rs361525 and rs1800629), and IFNγ (rs2069705). The best risk prediction model was identified based on precision and cross-validation consistency.

RESULTS

Multifactor-dimensionality reduction analysis detected a significant model with the genes TNFα, IFNγ, IL1α, and IL6 (prediction success: 72%, p < 0.0001). When risk factors were analyzed with these polymorphisms, the model achieved a similar prediction for dementia as the genes-only model.

CONCLUSION

These data indicate that gene-gene interactions form significant models to identify populations susceptible to dementia.

Genetic association study reveals impact of interleukin 10 polymorphisms on cognitive functions in schizophrenia

AIM

Cognitive deficits are the core factors impacting quality of life among patients diagnosed with schizophrenia. Effective method of treatment for this domain of symptoms remains lacking. Recent evidence suggests the link between impaired cognition and aberrant inflammatory response. Severity of symptoms might be linked to individual genetic predispositions and single-nucleotide polymorphisms (SNPs) in genes encoding interleukins and their receptors. Current genetic association studies include anti-inflammatory interleukins, such as IL10. Functional polymorphisms of IL10 (rs1800871, rs18008729) have been indicated to affect information processing in schizophrenia.

MATERIALS AND METHODS

In this study, we analyzed the potential impact of 27 functional SNPs in 8 cytokine genes on cognitive parameters measured by Wisconsin card-sorting test (WCST) in schizophrenia group (n = 150) and healthy controls (n = 152).

RESULTS

We found significant associations of two functional polymorphisms of IL10 (rs1800871, rs1800872) and WCST results. Allele A carriers in rs1800871 performed significantly better in Percent of Conceptual Level Responses (CLR%). Allele A carriers in rs1800871 and allele T carriers in rs1800872 obtained better results in Completed Categories (CC). The impact of illness duration was observed, with better performance of recent-onset patients.

CONCLUSIONS

Results of this study indicate that genetic variants of inflammatory response are associated with cognitive deficits in schizophrenia. The role of cytokines in schizophrenia need to be investigated in the aspect of pro-/anti-inflammatory imbalance. Altered inflammatory response promote chronic mild inflammation in the brain and aberrant synaptic plasticity.

Prenatal LPS exposure increases hippocampus IL-10 and prevents short-term memory loss in the male adolescent offspring of high-fat diet fed dams

Lipopolysaccharide (LPS) tolerance can reduce the neuroinflammation caused by high fat maternal diets; however, there are no reports that have evaluated the effects of prenatal LPS exposure on the memories of the offspring of high-fat diet fed dams. This study evaluated the effects of prenatal LPS exposure on the inflammatory parameters and redox status in the brain, as well as the object recognition memory of adolescent offspring of Wistar rat dams that were treated with a high-fat diet during gestation and lactation. Female pregnant Wistar rats randomly received a standard diet (17.5% fat) or a high-fat diet (45.0% fat) during gestation and lactation. On gestation days 8, 10, and 12, half of the females in each group were intraperitoneally treated with LPS (0.1 mg.kg-1). After weaning, the male offspring were placed in cages in standard conditions, and at 6 weeks old, animals underwent the novel object recognition test (for short- and long-term memory). The offspring of the high-fat diet fed dams showed increased hippocampus IL-6 levels (21-days-old) and impaired short-term memories. These effects were avoided in the offspring of high-fat diet fed dams submitted to prenatal LPS exposure, which showed greater hippocampus IL-10 levels (at 21- and 50-days-old), increased antioxidant activity (50-days-old) in the hippocampus and prefrontal cortex, without memory impairments (short- and long-term memory). IL-6 has been consistently implicated in memory deficits and as an endogenous mechanism for limiting plasticity, while IL-10 regulates glial activation and has a strong association with improvements in cognitive function. Prenatal LPS exposure preventing the increase of IL-6 in the hippocampus and the impairment to short-term object recognition memory caused by the high-fat maternal diet.

Cellular and molecular influencers of neuroinflammation in Alzheimer's disease: Recent concepts & roles

Alzheimer's disease (AD), an extremely common neurodegenerative disorder of the older generation, is one of the leading causes of death globally. Besides the conventional hallmarks i.e. Amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs), neuroinflammation also serves as a major contributing factor in the pathogenesis of AD. There are mounting evidences to support the fundamental role of cellular (microglia, astrocytes, mast cells, and T-cells) and molecular (cytokines, chemokines, caspases, and complement proteins) influencers of neuroinflammation in producing/promoting neurodegeneration and dementia in AD. Genome-wide association studies (GWAS) have revealed the involvement of various single nucleotide polymorphisms (SNPs) of genes related to neuroinflammation with the risk of developing AD. Modulating the release of the neuroinflammatory molecules and targeting their relevant mechanisms may have beneficial effects on the onset, progress and severity of the disease. Here, we review the distinct role of various mediators and modulators of neuroinflammation that impact the pathogenesis and progression of AD as well as incite further research efforts for the treatment of AD through a neuroinflammatory approach.

Influence of COMT polymorphism in cognitive performance on dementia in community-dwelling elderly Mexican (SADEM study)

There is an inconsistent finding about the relationship of catechol-O-methyltransferase (COMT) with dementia susceptibility, as well as with cognitive impairment. To substantiate this, we examined COMT genotype effects in certain cognitive domains in dementia. To evaluate the effects of COMT Val158Met on cognitive performance, we used The Mini-Mental State Examination (MMSE), the cognitive subscale of the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog) and the Syndrome Kurz Test (SKT). The results show COMT Val/Met, Val/Val genotype polymorphisms had a significant effect on cognition performance (OR = 1.75 (95 %CI 1.22-2.54) and (OR = 2.76 (95 %CI 1.78-4.26), p < 0.001), and with adjustment for all cognitive test scores together, Val/Val (OR = 4.98 (95 % CI 1.47-16.86) and Val/Met (OR = 3.62 (95 % CI 1.37-9.56) had effect. Our study allows us to understand the role of COMT in cognitive performance in dementia, as well as interaction with other known risk factors for this pathology. This data might help in developing new therapeutic targets for cognitive impairment, main symptom of dementia. Other risk genotypes or haplotypes should be evaluated to determine the association with cognitive decline in dementia.

IL-1β, IL-6, IL-10, and TNFα Single Nucleotide Polymorphisms in Human Influence the Susceptibility to Alzheimer's Disease Pathology

BACKGROUND

Neuroinflammation plays an important role in Alzheimer's disease (AD). During this process, activated microglia release pro-inflammatory cytokines such as interleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor α (TNFα) that participate in neuron damage, but also anti-inflammatory cytokines (such as IL-10), which maintain homeostasis of immune response. Previous studies showed the association of IL-1α -889C/T (rs1800587), IL-1β-1473G/C (rs1143623), IL-6 -174C/G (rs1800795), IL-10 -1082G/A (rs1800896), and TNFα -308A/G (rs1800629) polymorphisms with AD.

OBJECTIVE

We aimed to investigate whether people with certain IL-1α, IL-1β, IL-6, IL-10, and TNFα genotypes in these polymorphisms are more prone to develop AD-related pathology, reflected by pathological levels of cerebrospinal fluid (CSF) AD biomarkers including amyloid-β1-42, total tau (t-tau), tau phosphorylated at Thr 181 (p-tau181), Ser 199 (p-tau199), and Thr 231 (p-tau231), and visinin-like protein 1 (VILIP-1).

METHODS

The study included 115 AD patients, 53 patients with mild cognitive impairment, and 11 healthy controls. The polymorphisms were determined using real-time polymerase chain reaction. Levels of CSF biomarkers were determined by enzyme-linked immunosorbent assay.

RESULTS

A significant increase in p-tau CSF levels was found in patients with the AA IL-10 -1082G/A and GG TNFα -308A/G genotypes, and in carriers of a G allele in IL-1β -1473C/G and IL-6 -174C/G polymorphisms. t-tau levels were increased in carriers of a G allele in IL-1β -1473C/G polymorphism. An increase in VILIP-1 levels was observed in patients with CG and GG IL-1β -1473C/G, GC IL-6 -174C/G, and GG TNFα -308A/G genotype.

CONCLUSION

These results suggest that persons carrying certain genotypes in IL10 (-1082G/A), IL1β (1473C/G), IL6 (-174C/G), and TNFIα (-308A/G) could be more vulnerable to development of neuroinflammation, and consequently of AD.

Impact of IL-10 Promoter Polymorphisms and IL-10 Serum Levels on Advanced Laryngeal Squamous Cell Carcinoma and Survival Rate

BACKGROUND/AIM

Prognosis of advanced stages of laryngeal squamous cell carcinoma (LSCC) remains poor. To clarify therapeutic targets and improve survival rate, identification of new specific and prognostic biomarkers of LSCC is required. The study aimed to evaluate the impact of IL-10:rs1800871, rs1800872, rs1800896 single nucleotide polymorphisms (SNPs), and IL-10 serum levels on LSCC development and determine associations of selected SNPs with patient survival rate.

PATIENTS AND METHODS

A total of 300 LSCC patients and 533 controls were included in the study. Genotyping was carried out using RT-PCR; IL-10 serum levels were analyzed by ELISA.

RESULTS

Significant associations were identified between IL-10 rs1800871 variants and advanced stage of LSCC patient group in the codominant, recessive and additive models (OR=0.473, p=0.027; OR=0.510, p=0.040; and OR=0.733; p=0.037). Significant variants of IL-10 rs1800872 were determined in the codominant, recessive and additive models (OR=0.473, p=0.027; OR=0.510, p=0.040; and OR=0.733, p=0.037). The distribution of IL-10 SNPs genotypes did not impact LSCC patient survival rate (respectively, p=0.952; p=0.952; p=0.991).

CONCLUSION

IL-10:rs1800871 and rs1800872 SNPs are associated with advanced stage of LSCC. The genotypic distribution of IL-10 SNPs does not influence the survival rate of LSCC patients.

Relationship Between Genetic Variants of ACAT1 and APOE with the Susceptibility to Dementia (SADEM Study)

One of the hypotheses that have emerged to explain the origin of dementia relates the disease with altered lipid metabolism, particularly cholesterol. To maintain cholesterol homeostasis, the ACAT1 enzyme has an important function to regulate the production of Aβ. Moreover, APOE is the main cholesterol carrier in the brain, and it has been reported as a risk factor for this disease. This study evaluates the relationship between ACAT1 and APOE genetic variants with susceptibility for the development of Alzheimer's disease and other dementias. We examined four ACAT1 polymorphisms (rs2247071, rs2862616, rs3753526, rs1044925) and two in the APOE gene (rs7412, rs429358) in a group of 204 controls and 196 cases of dementia. Our results show one protective haplotype: CGCA (OR = 0.34, 95% CI = 0.23-0.46; p < 0.001) and one risk haplotype: CGGA (OR = 1.87, 95% CI = 1.34-2.60; p < 0.001) for the development of dementia. Subjects identified as APOE-ε4 allele carriers had a higher risk of developing dementia compared with non-carriers, OR = 13.33 (95% CI = 3.14-56.31). The results support the hypothesis that the ACAT1 gene, together with the APOE gene, plays an important role in susceptibility to the development of dementia and shows genetic characteristics of the Mexican population that can be used to identify the population at risk.

Association of genetic variants of ABCA1 with susceptibility to dementia: (SADEM study)

Because of the importance of cholesterol metabolism in the physiopathogenesis of dementia, and knowing the function of ATP-binding cassette A1 transporter (ABCA1) as a cholesterol flow pump at the cellular and cerebral level, it has been noted that the ABCA1 gene may be a good candidate for disease study. In order to evaluate the relationship between ABCA1 genetic variants and the risk of Alzheimer's disease and other dementia in Mexican individuals, we examined three ABCA1 polymorphisms located in the exonic region (rs2230808, rs2066718, rs2230806) and two in the promoter region (rs1800977, rs2422493) in a group of 557 normal controls and 221 cases of dementia. It was possible to distinguish one protective haplotype: CCCCGC (OR = 0,502, 95% CI = 0,370-0,681, p < 0.001), and one risk haplotype TCCCAT (OR = 2208, 95% CI = 1609-3031, p < 0.000) for the development of dementia. The results suggest that ABCA1 plays an important role in the pathophysiological mechanisms for the development of dementia.

Mesenchymal stem cells and cell-derived extracellular vesicles protect hippocampal neurons from oxidative stress and synapse damage induced by amyloid-β oligomers

Alzheimer's disease (AD) is a disabling and highly prevalent neurodegenerative condition, for which there are no effective therapies. Soluble oligomers of the amyloid-β peptide (AβOs) are thought to be proximal neurotoxins involved in early neuronal oxidative stress and synapse damage, ultimately leading to neurodegeneration and memory impairment in AD. The aim of the current study was to evaluate the neuroprotective potential of mesenchymal stem cells (MSCs) against the deleterious impact of AβOs on hippocampal neurons. To this end, we established transwell cocultures of rat hippocampal neurons and MSCs. We show that MSCs and MSC-derived extracellular vesicles protect neurons against AβO-induced oxidative stress and synapse damage, revealed by loss of pre- and postsynaptic markers. Protection by MSCs entails three complementary mechanisms: 1) internalization and degradation of AβOs; 2) release of extracellular vesicles containing active catalase; and 3) selective secretion of interleukin-6, interleukin-10, and vascular endothelial growth factor to the medium. Results support the notion that MSCs may represent a promising alternative for cell-based therapies in AD.

Alzheimer’s disease and cytokine IL-10 gene polymorphisms: is there an association?

ABSTRACT Alzheimer’s disease (AD) is the most common form of dementia. In the last 15 years, a new theory has proposed the autoimmune mechanism as a trigger for AD. Studies on the association between AD and inflammatory biomarkers have yielded controversial results. Interleukin-10 (IL-10), an anti-inflammatory mediator, has been pointed out as one of the main cytokines associated with the occurrence of AD. Moreover, treatment that increases IL-10 levels could be a potential therapy for AD, since this cytokine acts on amyloid and pro-inflammatory molecule reduction. Based on the current literature, this study reviews evidence regarding the role of IL-10 polymorphisms in the context of AD, which has been shown to be of paramount importance for attenuating neuroinflammation, cognitive dysfunction and neurodegeneration.

Serum Interleukin-10 Levels Correlate with Cerebrospinal Fluid Amyloid Beta Deposition in Alzheimer Disease Patients

BACKGROUND AND OBJECTIVE

In Alzheimer disease (AD) inflammation becomes evident throughout the course of the disease. However, the association between inflammation, cognitive impairment, and cerebrospinal biomarkers (Aβ42, t-tau, p-tau181, and Aβ42/p-tau181 ratio) is poorly understood.

METHODS

A large panel of inflammatory cytokines (interleukin [IL]-1β, IL-1ra, IL-2, IL-4, IL-6, IL-10, IL-17, interferon-γ, tumor necrosis factor-α, and vascular endothelial growth factor) was analyzed using a multiplex immunoassay in 27 patients with a diagnosis of AD dementia and in 18 control subjects. In a subgroup with available cerebrospinal fluid (CSF) samples, cytokines in serum were correlated with the levels of neurodegenerative CSF biomarkers (Aβ42, t-tau, p-tau181, and Aβ42/p-tau181 ratio).

RESULTS

Compared to control subjects, AD patients showed a significant upregulation of IL-10, IL-1β, and IL-17 serum levels. Several cytokines appeared intercorrelated, and IL-10 in particular presented a significant inverse correlation with CFS levels of Aβ42 and the Aβ42/p-tau ratio.

CONCLUSION

Our findings indicate that serum levels of IL-10 may represent a possible peripheral expression of amyloid beta deposition in AD patients.