Obesity as a risk factor for Alzheimer's disease: the role of adipocytokines

Alzheimer's disease is the leading cause of dementia and the most prevalent neurodegenerative disease. It is an aging-related multi-factorial disorder and growing evidence support the contribution of metabolic factors to what was formerly thought to be a centrally mediated process. Obesity has already been recognized as an important player in the pathogenesis of this type of dementia, independently of insulin resistance or other vascular risk factors. Although the exact underlying mechanisms are still unknown, adipocyte dysfunction and concomitant alteration in adipocyte-derived protein secretion seem to be involved, since these adipocytokines can cross the blood-brain barrier and influence cognitive-related structures. Very few studies have assessed the role of adipocytokines dysfunction on cognitive impaired patients and yielded contradictory results. Interestingly, extensive research on the central effects of leptin in Alzheimer's disease-transgenic mice has demonstrated its capacity to enhance synaptic plasticity and strength, as well as to prevent beta-amyloid deposition and tau phosphorylation. In addition, adiponectin, the most abundant adipocytokine whose levels are inversely correlated to adiposity, has shown to be neuroprotective to hippocampal cells. Many other adipose-derived cytokines have mainly pro-inflammatory properties, being able to trigger and/or enhance central inflammatory cascades and also to influence the secretion of other adipocytokines involved in cognition. This paper pretends to review the existing evidence on the contribution of adipocytokines dysfunction to the increased risk of dementia associated with mid-life obesity, unraveling its insulin-independent effects on cognition.info:eu-repo/semantics/publishedVersio

Characterization of an FTLD-PDB family with the coexistence of SQSTM1 mutation and hexanucleotide (G4C2) repeat expansion in C9orf72 gene

The C9orf72 expansion is considered a major genetic cause of familial frontotemporal dementia (FTD) in several patients' cohorts. Interestingly, C9orf72 expansion carriers, present also abundant neuronal p62-positive inclusions. Although p62/SQSTM1 mutations were initially associated with Paget disease of bone (PDB), they have been also identified in FTD. We describe an FTD-PDB family in which the proband presented with behavioral FTD phenotype and concomitant Paget disease. The molecular genetic analysis revealed the co-occurrence of 2 mutations; the pathogenic C9orf72 expansion and p.P392L heterozygous missense mutation in SQSTM1 gene. Amongst the 6 family members analyzed, the p.P392L SQSTM1 mutation segregated as expected with PDB, whereas the C9orf72 expansion segregated with frontal cognitive impairment or dementia in all but one carrier. The coexistence of these conditions could be underestimated since neither patients with FTD nor patients with PDB undergo bone scintigraphy or cognitive assessment, respectively. The number of cases with double mutations could also be over looked as the molecular strategy adopted in most laboratories ends with the identification of one pathogenic mutation in one of the known causative genes. Therefore, we advocate for further clinical and molecular evaluation in suspect cases

Interaction between IRF6 and TGFA Genes Contribute to the Risk of Nonsyndromic Cleft Lip/Palate

Previous evidence from tooth agenesis studies suggested IRF6 and TGFA interact. Since tooth agenesis is commonly found in individuals with cleft lip/palate (CL/P), we used four large cohorts to evaluate if IRF6 and TGFA interaction contributes to CL/P. Markers within and flanking IRF6 and TGFA genes were tested using Taqman or SYBR green chemistries for case-control analyses in 1,000 Brazilian individuals. We looked for evidence of gene-gene interaction between IRF6 and TGFA by testing if markers associated with CL/P were overtransmitted together in the case-control Brazilian dataset and in the additional family datasets. Genotypes for an additional 142 case-parent trios from South America drawn from the Latin American Collaborative Study of Congenital Malformations (ECLAMC), 154 cases from Latvia, and 8,717 individuals from several cohorts were available for replication of tests for interaction. Tgfa and Irf6 expression at critical stages during palatogenesis was analyzed in wild type and Irf6 knockout mice. Markers in and near IRF6 and TGFA were associated with CL/P in the Brazilian cohort (p<10-6). IRF6 was also associated with cleft palate (CP) with impaction of permanent teeth (p<10-6). Statistical evidence of interaction between IRF6 and TGFA was found in all data sets (p = 0.013 for Brazilians; p = 0.046 for ECLAMC; p = 10-6 for Latvians, and p = 0.003 for the 8,717 individuals). Tgfa was not expressed in the palatal tissues of Irf6 knockout mice. IRF6 and TGFA contribute to subsets of CL/P with specific dental anomalies. Moreover, this potential IRF6-TGFA interaction may account for as much as 1% to 10% of CL/P cases. The Irf6-knockout model further supports the evidence of IRF6-TGFA interaction found in humans. © 2012 Letra et al

Oxidative stress involving changes in Nrf2 and ER stress in early stages of Alzheimer's disease

AbstractOxidative stress and endoplasmic reticulum (ER) stress have been associated with Alzheimer's disease (AD) progression. In this study we analyzed whether oxidative stress involving changes in Nrf2 and ER stress may constitute early events in AD pathogenesis by using human peripheral blood cells and an AD transgenic mouse model at different disease stages. Increased oxidative stress and increased phosphorylated Nrf2 (p(Ser40)Nrf2) were observed in human peripheral blood mononuclear cells (PBMCs) isolated from individuals with mild cognitive impairment (MCI). Moreover, we observed impaired ER Ca2+ homeostasis and increased ER stress markers in PBMCs from MCI individuals and mild AD patients. Evidence of early oxidative stress defense mechanisms in AD was substantiated by increased p(Ser40)Nrf2 in 3month-old 3xTg-AD male mice PBMCs, and also with increased nuclear Nrf2 levels in brain cortex. However, SOD1 protein levels were decreased in human MCI PBMCs and in 3xTg-AD mice brain cortex; the latter further correlated with reduced SOD1 mRNA levels. Increased ER stress was also detected in the brain cortex of young female and old male 3xTg-AD mice. We demonstrate oxidative stress and early Nrf2 activation in AD human and mouse models, which fails to regulate some of its targets, leading to repressed expression of antioxidant defenses (e.g., SOD-1), and extending to ER stress. Results suggest markers of prodromal AD linked to oxidative stress associated with Nrf2 activation and ER stress that may be followed in human peripheral blood mononuclear cells

Women Are More Susceptible to Caries but Individuals Born with Clefts Are Not

The identification of individuals at a higher risk of developing caries is of great interest. Isolated forms of cleft lip and palate are among the most common craniofacial congenital anomalies in humans. Historically, several reports suggest that individuals born with clefts have a higher risk for caries. Caries continues to be the most common infectious noncontagious disease worldwide and a great burden to any health system. The identification of individuals of higher susceptibility to caries is of great interest. In this paper, we assessed caries experience of 1,593 individuals from three distinct populations. The study included individuals born with clefts, their unaffected relatives, and unrelated unaffected controls that were recruited from areas with similar cultural pressures and limited access to dental care. DMFT/dmft scores were obtained, and caries experience rates were compared among the three groups in each geographic area. Individuals born with clefts did not present higher caries experience in comparison to their unaffected relatives or unrelated unaffected controls. Women tend to present higher caries rates in comparison to men. Our work provides strong evidence that individuals born with clefts are not at higher risk to caries; however, women tend to have more severe caries experience

Women are more susceptible to caries but individuals born with clefts are not

The identification of individuals at a higher risk of developing caries is of great interest. Isolated forms of cleft lip and palate are among the most common craniofacial congenital anomalies in humans. Historically, several reports suggest that individuals born with clefts have a higher risk for caries. Caries continues to be the most common infectious noncontagious disease worldwide and a great burden to any health system. The identification of individuals of higher susceptibility to caries is of great interest. In this paper, we assessed caries experience of 1,593 individuals from three distinct populations. The study included individuals born with clefts, their unaffected relatives, and unrelated unaffected controls that were recruited from areas with similar cultural pressures and limited access to dental care. DMFT/dmft scores were obtained, and caries experience rates were compared among the three groups in each geographic area. Individuals born with clefts did not present higher caries experience in comparison to their unaffected relatives or unrelated unaffected controls. Women tend to present higher caries rates in comparison to men. Our work provides strong evidence that individuals born with clefts are not at higher risk to caries; however, women tend to have more severe caries experience.Instituto Multidisciplinario de Biología Celula

Detection of Streptococcus mutans Genomic DNA in Human DNA Samples Extracted from Saliva and Blood

Caries is a multifactorial disease, and studies aiming to unravel the factors modulating its etiology must consider all known predisposing factors. One major factor is bacterial colonization, and Streptococcus mutans is the main microorganism associated with the initiation of the disease. In our studies, we have access to DNA samples extracted from human saliva and blood. In this report, we tested a real-time PCR assay developed to detect copies of genomic DNA from Streptococcus mutans in 1,424 DNA samples from humans. Our results suggest that we can determine the presence of genomic DNA copies of Streptococcus mutans in both DNA samples from caries-free and caries-affected individuals. However, we were not able to detect the presence of genomic DNA copies of Streptococcus mutans in any DNA samples extracted from peripheral blood, which suggests the assay may not be sensitive enough for this goal. Values of the threshold cycle of the real-time PCR reaction correlate with higher levels of caries experience in children, but this correlation could not be detected for adults

Detection of Streptococcus mutans Genomic DNA in Human DNA Samples Extracted from Saliva and Blood

Caries is a multifactorial disease, and studies aiming to unravel the factors modulating its etiology must consider all known predisposing factors. One major factor is bacterial colonization, and Streptococcus mutans is the main microorganism associated with the initiation of the disease. In our studies, we have access to DNA samples extracted from human saliva and blood. In this report, we tested a real-time PCR assay developed to detect copies of genomic DNA from Streptococcus mutans in 1,424 DNA samples from humans. Our results suggest that we can determine the presence of genomic DNA copies of Streptococcus mutans in both DNA samples from caries-free and caries-affected individuals. However, we were not able to detect the presence of genomic DNA copies of Streptococcus mutans in any DNA samples extracted from peripheral blood, which suggests the assay may not be sensitive enough for this goal. Values of the threshold cycle of the real-time PCR reaction correlate with higher levels of caries experience in children, but this correlation could not be detected for adults

Women are more susceptible to caries but individuals born with clefts are not

The identification of individuals at a higher risk of developing caries is of great interest. Isolated forms of cleft lip and palate are among the most common craniofacial congenital anomalies in humans. Historically, several reports suggest that individuals born with clefts have a higher risk for caries. Caries continues to be the most common infectious noncontagious disease worldwide and a great burden to any health system. The identification of individuals of higher susceptibility to caries is of great interest. In this paper, we assessed caries experience of 1,593 individuals from three distinct populations. The study included individuals born with clefts, their unaffected relatives, and unrelated unaffected controls that were recruited from areas with similar cultural pressures and limited access to dental care. DMFT/dmft scores were obtained, and caries experience rates were compared among the three groups in each geographic area. Individuals born with clefts did not present higher caries experience in comparison to their unaffected relatives or unrelated unaffected controls. Women tend to present higher caries rates in comparison to men. Our work provides strong evidence that individuals born with clefts are not at higher risk to caries; however, women tend to have more severe caries experience.Instituto Multidisciplinario de Biología Celula