Changes in Expression of Key Genes in Alzheimer's Disease: A Specific Brain Tissue Change

Alzheimer's disease (AD) is an irreversible and neurodegenerative disorder. Its etiology is not clear, but the involvement of genetic components plays a central role in the onset of the disease. In the present study, the expression of 10 genes (APP, PS1 and PS2, APOE, APBA2, LRP1, GRIN2B, INSR, GJB1, and IDE) involved in the main pathways related to AD were analyzed in auditory cortices and cerebellum from 29 AD patients and 29 healthy older adults. Raw analysis revealed tissue-specific changes in genes LRP1, INSR, and APP. A correlation analysis showed a significant effect also tissue-specific AD in APP, GRIN2B, INSR, and LRP1. Furthermore, the E4 allele of the APOE gene revealed a significant correlation with change expression tissue-specific in ABPA2, APP, GRIN2B, LRP1, and INSR genes. To assess the existence of a correction between changes in target gene expression and a probability of AD in each tissue (auditory cortices and cerebellum) an analysis of the effect of expressions was realized and showed that the reduction in the expression of the APP in auditory cortex and GRIN2B cerebellum had a significant effect in increasing the probability of AD, in the same logic, our result also suggesting that increased expression of the LRP1 and INSR genes had a significant effect on increasing the probability of AD. Our results showed tissue-specific gene expression alterations associated with AD and certainly opened new perspectives to characterize factors involved in gene regulation and to obtain possible biomarkers for AD.

Development and validation of a questionnaire to measure association factors with suicide

Background and Aims

Our goal was to develop an online questionnaire to survey the prevalence of suicidal behavior.

Methods

We developed a questionnaire with 51 variables and proceeded with validations. Validations were performed using face validity, content validity, and construct validity. Reliability was performed by test-rest.

Results

The face validity was 1.0 and the content validity was 0.91. The exploratory factor analysis got Kaiser-Meyer-Olkin = 0.86 and extracted one principal factor. The confirmatory factor analysis demonstrates root mean square error of approximation = 0.000 and comparative fit index = 1.000. The test-retest had an intraclass correlated coefficient of 0.98.

Conclusion

The adequate development questionnaire was validated, and we have an instrument to survey suicide behaviors during the pandemic time.

Patient or Public Contribution

The general population of Marília voluntarily responded to the questionnaire, as well as patients from the principal investigator's office.

The Relationship between Type 1 Diabetes Mellitus, TNF-α, and IL-10 Gene Expression

Type 1 diabetes mellitus (T1DM) is one of the major chronic diseases in children worldwide. This study aimed to investigate interleukin-10 (IL-10) gene expression and tumor necrosis factor-alpha (TNF-α) in T1DM. A total of 107 patients were included, 15 were T1DM in ketoacidosis, 30 patients had T1DM and HbA1c ≥ 8%; 32 patients had T1DM and presented HbA1c < 8%; and 30 were controls. The expression of peripheral blood mononuclear cells was performed using the reverse transcriptase-polymerase chain reaction in real time. The cytokines gene expression was higher in patients with T1DM. The IL-10 gene expression increased substantially in patients with ketoacidosis, and there was a positive correlation with HbA1c. A negative correlation was found for IL-10 expression and the age of patients with diabetes, and the time of diagnosis of the disease. There was a positive correlation between TNF-α expression with age. The expression of IL-10 and TNF-α genes showed a significant increase in DM1 patients. Once current T1DM treatment is based on exogenous insulin, there is a need for other therapies, and inflammatory biomarkers could bring new possibilities to the therapeutic approach of the patients.

CDK10, CDK11, FOXO1, and FOXO3 Gene Expression in Alzheimer's Disease Encephalic Samples

Alzheimer's disease (AD) is a progressive neuroinflammatory and neurodegenerative disorder that affects different regions of the brain. Its pathophysiology includes the accumulation of β-amyloid protein, formation of neurofibrillary tangles, and inflammatory processes. Genetic factors are involved in the onset of AD, but they are not fully elucidated. Identification of gene expression in encephalic tissues of patients with AD may help elucidate its development. Our objectives were to characterize and compare the gene expression of CDK10, CDK11, FOXO1, and FOXO3 in encephalic tissue samples from AD patients and elderly controls, from the auditory cortex and cerebellum. RT-qPCR was used on samples from 82 individuals (45 with AD and 37 controls). We observed a statistically significant increase in CDK10 (p = 0.029*) and CDK11 (p = 0.048*) gene expression in the AD group compared to the control, which was most evident in the cerebellum. Furthermore, the Spearman test demonstrated the presence of a positive correlation of gene expression both in the auditory cortex in the AD group (r = 0.046/p = 0.004) and control group (r = 0.454/p = 0.005); and in the cerebellum in the AD group (r = 0.654 /p < 0.001). There was no statistically significant difference and correlation in the gene expression of FOXO1 and FOXO3 in the AD group and the control. In conclusion, CDK10 and CDK11 have high expression in AD patients compared to control, and they present a positive correlation of gene expression in the analyzed groups and tissues, which suggests that they play an important role in the pathogenesis of AD.

Transcriptomic Profiling of Rectus Abdominis Muscle in Women with Gestational Diabetes-Induced Myopathy: Characterization of Pathophysiology and Potential Muscle Biomarkers of Pregnancy-Specific Urinary Incontinence

Gestational diabetes mellitus (GDM) is recognized as a "window of opportunity" for the future prediction of such complications as type 2 diabetes mellitus and pelvic floor muscle disorders, including urinary incontinence and genitourinary dysfunction. Translational studies have reported that pelvic floor muscle disorders are due to a GDM-induced-myopathy (GDiM) of the pelvic floor muscle and rectus abdominis muscle (RAM). We now describe the transcriptome profiling of the RAM obtained by Cesarean section from GDM and non-GDM women with and without pregnancy-specific urinary incontinence (PSUI). We identified 650 genes in total, and the differentially expressed genes were defined by comparing three control groups to the GDM with PSUI group (GDiM). Enrichment analysis showed that GDM with PSUI was associated with decreased gene expression related to muscle structure and muscle protein synthesis, the reduced ability of muscle fibers to ameliorate muscle damage, and the altered the maintenance and generation of energy through glycogenesis. Potential genetic muscle biomarkers were validated by RT-PCR, and their relationship to the pathophysiology of the disease was verified. These findings help elucidate the molecular mechanisms of GDiM and will promote the development of innovative interventions to prevent and treat complications such as post-GDM urinary incontinence.

Level of physical activity and gene expression of IL-10 and TNF-α in children and adolescents with Type 1 diabetes

AIMS

The gene expressions of IL-10 and TNF-α have been identified as important factors of the clinical condition in type I diabetes mellitus (DM1). However, the effect of physical exercise on the expression of these markers is poorly understood. Our objective was to evaluate the relationship between the level of physical activity (LPA) and the gene expressions of IL-10 and TNF-α, as the relationship with glycemic control and insulin reserve in children and adolescents with DM1.

METHODS

108 participants (1-23 years), were divided into 4 groups: DM1 with ketoacidosis (KETO) (n = 15); Decompensated DM1 (DM1d) (n = 32); Compensated DM1 (DM1c) (n = 30); and healthy control (C) (n = 30). The level of physical activity (LPA) was classified as low active, active, and very active. So evaluated Fasting blood glucose, HbA1c, C-peptide, and gene expressions of IL-10 and TNF-α.

RESULTS

The increase in the level of physical activity significantly affected the expression of TNF-α in the DMd and C groups. The increase in LPA from low to active reduced the gene expression of IL-10; however, the increase in NAF from active to very active was associated with an increase in IL-10 gene expression. A very active LPA contributes to reducing HbA1c and an increase in C-peptide in the KETO group.

CONCLUSION

The increase in LPA demonstrated a significant effect on the improvement of IL-10 and TNF-α gene expression in the KETO and DMd groups; however, in the KETO group, improvements were also observed in the percentage of HbA1C and C-peptide.

Increased expression of interleukin-6 gene in gastritis and gastric cancer

Helicobacter pylori (H. pylori) induces an intense inflammatory response, mediated by proinflammatory cytokines, including interleukin (IL)-6 and its membrane receptor (IL-6R), which activates important signaling pathways in the development of gastric disease and cancer. We investigated the gene and protein expression of IL-6 and IL-6R and the influence of polymorphisms rs1800795, rs1800796, and rs1800797 on its gene expression together with H. pylori infection. Furthermore, an in-silico analysis was performed to support our results. Gastric biopsies were obtained from patients with gastric symptoms and patients with gastric cancer (GC) and were divided into groups (Control, Gastritis, and Cancer). H. pylori was detected by PCR. Real-time-qPCR was employed to determine gene expression, and western blot assay was used to analyze protein expression levels. PCR-RFLP was used to characterize IL-6 polymorphisms. Bioinformatics analyses were performed using the Gene Expression Omnibus (GEO) database and GEO2R to screen out differentially expressed genes (DEGs). H. pylori was detected in 43.3% of the samples. Statistically significant differences were found for IL-6 (P=0.0001) and IL-6R (P=0.0005) genes among the three groups, regardless of the presence of H. pylori. Among patients with H. pylori infection, the IL-6 and IL-6R gene and protein expressions were significantly increased, highlighting IL-6 gene overexpression in patients with GC. No statistically significant differences were found for the rs1800795, rs1800796, and rs1800797 polymorphisms compared to IL-6 gene expression. The results indicated that the IL-6 polymorphisms do not influence its expression, but IL-6 and IL-6R expression seems to be altered by the presence of H. pylori.

Dysregulated Expression of Apoptosis-Associated Genes and MicroRNAs and Their Involvement in Gastric Carcinogenesis

PURPOSE

Analyze the expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b in patients with normal gastric tissue, chronic gastritis, and gastric adenocarcinoma.

METHODS

The expression of caspase-9, Smac/DIABLO, XIAP, let-7a, and let-7b by qRT-PCR was analyzed in 158 samples from 53 patients with normal gastric mucosa, 86 with chronic gastritis, and 19 with gastric cancer.

RESULTS

The comparison between the gastric cancer and the control group revealed a decreased expression of caspase-9 in gastric cancer tissues; considering the Helicobacter pylor presence, comparable results were revealed. Smac/DIABLO was increased in gastric cancer cells, while XIAP demonstrated no significant difference in the gene expression. The microRNA analysis revealed a decreased expression of let-7a and let-7b in samples positive to H. pylori infection and in gastric cancer group, regardless of the presence of the bacterium.

CONCLUSION

Our study provided some evidence of low activity of the intrinsic apoptosis pathway, as well as the influence of H. pylori on let-7a and let-7b expression.

The impact of DNA demethylation on the upregulation of the NRN1 and TNFAIP3 genes associated with advanced gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Very few therapeutic options are currently available in this neoplasia. The use of 5-Aza-2'-deoxycytidine (5-AZAdC) was approved for the treatment of myelodysplastic syndromes, and this drug can treat solid tumours at low doses. Epigenetic manipulation of GC cell lines is a useful tool to better understand gene expression regulatory mechanisms for clinical applications. Therefore, we compared the gene expression profile of 5-AZAdC-treated and untreated GC cell lines by a microarray assay. Among the genes identified in this analysis, we selected NRN1 and TNFAIP3 to be evaluated for gene expression by RT-qPCR and DNA methylation by bisulfite DNA next-generation sequencing in 43 and 52 pairs of GC and adjacent non-neoplastic tissue samples, respectively. We identified 83 candidate genes modulated by DNA methylation in GC cell lines. Increased expression of NRN1 and TNFAIP3 was associated with advanced tumours (P < 0.05). We showed that increased NRN1 and TNFAIP3 expression seems to be regulated by DNA demethylation in GC samples: inverse correlations between the mRNA and DNA methylation levels in the promoter of NRN1 (P < 0.05) and the intron of TNFAIP3 (P < 0.05) were detected. Reduced NRN1 promoter methylation was associated with III/IV TNM stage tumours (P = 0.03) and the presence of Helicobacter pylori infection (P = 0.02). The identification of demethylated activated genes in GC may be useful in clinical practice, stratifying patients who are less likely to benefit from 5-AZAdC-based therapies. KEY MESSAGES: Higher expression of NRN1 and TNFAIP3 is associated with advanced gastric cancer (GC). NRN1 promoter hypomethylation contributes to gene upregulation in advanced GC. TNFAIP3 intronic-specific CpG site demethylation contributes to gene upregulation in GC. These findings may be useful to stratify GC patients who are less likely to benefit from DNA demethylating-based therapies.

Xenotransplantation of human dental pulp stem cells in platelet-rich plasma for the treatment of full-thickness articular cartilage defects in a rabbit model

Stem cells in platelet-rich plasma (PRP) scaffolds may be a promising treatment for cartilage repair. Human dental pulp stem cell (hDPSC) subpopulations have been identified to have substantial angiogenic, neurogenic and regenerative potential when compared with other stem cell sources. The present study evaluated the potential of hDPSCs in a PRP scaffold to regenerate full-thickness cartilage defects in rabbits. Full-thickness articular cartilage defects were created in the patellar groove of the femur of 30 rabbits allocated into three experimental groups: Those with an untreated critical defect (CTL), those treated with PRP (PRP) and those treated with stem cells in a PRP scaffold (PRP+SC). The patellar grooves of the femurs from the experimental groups were evaluated macroscopically and histologically at 6 and 12 weeks post-surgery. The synovial membranes were also collected and evaluated for histopathological analysis. The synovial lining cell layer was enlarged in the CTL group compared with the PRP group at 6 weeks (P=0.037) but not with the PRP+SC group. All groups exhibited low-grade synovitis at 6 weeks and no synovitis at 12 weeks. Notably, macroscopic grades for the area of articular cartilage repair for the PRP+SC group were significantly improved compared with those in the CTL (P=0.001) and PRP (P=0.049) groups at 12 weeks. Furthermore, histological scores (modified O'Driscoll scoring system) of the patellar groove articular cartilage in the PRP+SC and PRP groups, in which the articular cartilage was primarily hyaline-like, were significantly higher compared with those in the CTL group at 12 weeks (P=0.002 and P=0.007, respectively). The present results support the therapeutic use of hDPSCs for the treatment of full-thickness articular cartilage defects.

Epidemiological and cytogenetic profiles of patients with hematological malignancies and their relationship with aging

Background

Hematologic neoplasms are associated with mutations in hematopoietic cells and chromosomal abnormalities. During aging, about 2–3% of the elderly have chromosomal abnormalities arising from clonal mosaicism, the immune system is impaired and the bone marrow loses its ability to replace blood cells.

Objective

To describe the epidemiological and cytogenetic profile of hematological malignancies, highlighting the frequency of chromosomal alterations in these neoplasms associated with aging.

Method

A retrospective cross-sectional study with analysis of karyotype exams results was performed in the Cytogenetic Laboratory of thee Blood Center of the Faculdade de Medicina de Marilia (FAMEMA) between 1998 and 2016. Blood samples from child and adult patients with different hematological malignancies treated in the Onco-hematology Outpatient Clinics of the local blood center and hospitals, and external clinics were tested.

Results

Karyotype exam results of 746 patients with a mean age of 54.7 years (±23.1) were analyzed. The elderly had the highest frequency of hematological malignancies (50.9%), followed by adults (38.3%) and young people (10.7%); elderly women had the highest percentage (55.0%). Normal karyotypes (46,XX/46,XY) were more common (61.8%) compared to abnormal karyotypes, especially among the elderly (56.4%). Myeloproliferative neoplasms were an exception with 67.4% of abnormal karyotypes.

Conclusion

There is a higher frequency of hematological malignancies among the elderly. It is possible to conclude that failures in genomic mechanisms and hematopoiesis with aging lead to the formation of cells with the chromosomal alterations found in hematological malignancies.

Investigação citogenética de translocação envolvendo os cromossomos 1 e 18 de pacientes com relato de aborto

As anomalias cromossômicas constituem uma proporção significativa das doenças genéticas, responsáveis por grande parte das malformações congênitas múltiplas e deficiências intelectuais, abortos espontâneos, além de desempenhar um importante papel na patogenia do câncer. Estas anomalias podem ser numéricas ou estruturais. Os rearranjos estruturais resultam da quebra, recombinação ou troca cromossômica, seguida de reconstituição em uma combinação anormal. São classificados como: balanceados, se o genoma possui o complemento normal de material cromossômico; ou desbalanceados, quando existe material adicional ou ausente. Este trabalho teve como objetivo realizar a investigação citogenética de um casal com relato de aborto espontâneo, em função de trissomia do cromossomo 18 (Síndrome de Edwards), para melhor definição do diagnóstico. O cariótipo da paciente, obtido após cultura temporária de linfócitos e análise por bandamento G, revelou uma translocação aparentemente balanceada, envolvendo o braço longo dos cromossomos 1 e 18, [46, XX,t(1;18)(q43;q21)]. Foi observado cariótipo normal do seu esposo e o cariótipo da filha do casal evidenciou a mesma translocação, aparentemente balanceada, da mãe. O estudo citogenético dos pais da paciente, evidenciou o seguinte cariótipo: a mãe com a mesma translocação aparentemente balanceada e o pai apresentou cariótipo normal. Foram estudados os demais membros da família. De acordo com a literatura, os rearranjos cromossômicos balanceados podem representar um risco aumentado de surgimento de alterações citogenéticas às gerações subsequentes, porque os portadores são mais suscetíveis a produzir uma frequência significativa de gametas desbalanceados e, portanto, têm um risco aumentado de ter uma prole anormal com cariótipos desbalanceados. Salientamos desta forma a importância da pesquisa do heredograma e estudo citogenético para definição do diagnóstico familial e aconselhamento genético preciso.

Estudo e segregação familial de paciente com fenótipo anormal, sendo os pais portadores de duas diferentes translocações

Os distúrbios cromossômicos constituem uma importante categoria de doenças Genéticas sendo responsáveis por uma considerável proporção de perdas reprodutivas, malformações congênitas e deficiências intelectuais, desempenhando um importante papel na patogênese das doenças malignas. Esses distúrbios podem ser numéricos ou rearranjos estruturais que resultam da quebra, recombinação ou troca cromossômica, seguida de reconstituição em uma combinação anormal. São classificados como balanceados ou desbalanceados, sendo que estes últimos produzem perda ou ganho de material cromossômico. Relatamos achados clínicos, citogenético por bandamento G e citogenético molecular pela técnica de SKY (Cariótipo espectral) de uma paciente portadora de translocação envolvendo os cromossomos 8 e 13 [46, XX,t(8;13)(q22;q32)], com fenótipo anormal, o qual sugere desequilíbrios cromossômicos ou genômicos. O estudo citogenético de seus pais, ambos fenotipicamente normais, evidenciou a mesma translocação no cariótipo do pai e a análise citogenética da mãe revelou translocação aparentemente balanceada envolvendo o braço curto dos cromossomos 3 e 16 [46, XX,t(3;16)(p21;p13)]. As translocações aparentemente balanceadas geralmente não possuem efeito fenotípico, uma vez que a troca é recíproca. No entanto, como ocorre em outros rearranjos estruturais balanceados, elas estão associadas a um maior risco de gametas desbalanceados e progênie anormal, como o relato deste caso. Ainda, de acordo com a literatura, é rara a ocorrência de evento familial apresentando duas alterações estruturais diferentes envolvendo quatro cromossomos entre indivíduos não aparentados. Salientamos, ainda, a importância de um melhor entendimento dos mecanismos de segregação de rearranjos críticos como esse, com importância clínica, através do uso de diferentes técnicas com o intuito de orientar o aconselhamento genético.

Prostanoids counterbalance the synergism between endothelin-1 and angiotensin II in mesenteric veins of trained rats

Exercise-induced adaptations of the modulating mechanisms that influence the angiotensin (Ang II) responses assume different features depending on the venous bed. In femoral veins, exercise mobilizes vasodilator prostanoids to cooperate with NO in order to maintain reduced Ang II responses. On the other hand, exercise's influence on the Ang II responses in veins that drain blood from the mesenteric region has been poorly described. Therefore, the present study aimed to identify the effects of a single bout of exercise, as well as exercise training, on the Ang II responses in mesenteric veins. The present study also aimed to investigate the involvement of prostanoids, NO and ET-1 in eventual exercise-induced modifications in these veins. To this end, mesenteric veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in organ baths. In addition, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as that of the ET_A and ET_B receptors, were quantified by real-time PCR in these veins. The results show that, either in absence or in presence of L-NAME, the Ang II responses were not different between groups. In the presence of indomethacin, higher Ang II responses were observed in the resting-trained animals than in the resting-sedentary animals. This difference, however, disappeared when L-NAME, BQ-123 or BQ-788 were added during incubation. In addition, no differences in ppET-1, ET_A or ET_B mRNA expression were observed between groups. Furthermore, in the presence of PD123,319, the Ang II responses in the exercised-sedentary animals were higher than those in the resting-sedentary animals. In conclusion, exercise training mobilizes endothelin-1 (ET-1) to reinforce the Ang II-induced responses mainly through ET_A activation. On the other hand, vasodilator prostanoids are mobilized to act in parallel with NO in order to counterbalance the Ang II responses that have been potentiated by ET-1 in these trained animals.

Downregulated Expression of E-cadherin and TP53 in Patients with Gastric Diseases: the Involvement of H. pylori Infection and Its Virulence Markers

PURPOSE

Gastritis caused by infection with Helicobacter pylori is characterized by chronic inflammation and damage in gastric tissue, which is a main risk factor for gastric cancer. Associated with H. pylori, the TP53 gene tumor suppressor and the cell adhesion glycoprotein epithelial cadherin develop a relevant role in the integrity and carcinogenesis of the epithelium. We aimed to detection of H. pylori and its main virulence markers and measured the messenger RNA (mRNA) expression levels of E-cadherin and TP53 genes.

METHODS

The detection of H. pylori and its virulence markers, as well as the mRNA expression levels of E-cadherin and TP53 genes, were obtained for 161 samples of gastric biopsies including 37 with normal gastric tissue, 70 with gastritis, 24 from neoplastic tissue, and 27 from adjacent non-neoplastic by means of a quantitative real-time polymerase chain reaction.

RESULTS

The mRNA expression levels of E-cadherin and TP53 were found to be decreased in patients with gastritis, independently of H. pylori infection. In samples from gastric patients, the neoplastic tissue showed an accentuated decrease of expression; on the other hand, the expression of E-cadherin was normal in adjacent non-neoplastic.

CONCLUSIONS

No evidence was found of the involvement of the cagA and vacA genes in the decreased expression of E-cadherin and TP53. The process of carcinogenesis is complex, and the decrease of the E-cadherin gene expression and TP53 gene expression appears to contribute significantly.

Helicobacter pylori and its reservoirs: A correlation with the gastric infection

Helicobacter pylori (H. pylori) has long been found to cause gastric diseases such as gastritis, gastric ulcers and gastric cancer. The transmission medium of this bacterium has yet to be determined, though several studies have speculated that the oral cavity is a reservoir for H. pylori. Others have also reported that the oral cavity may be a source of both transmission and gastric reinfection; however, such results are controversial. We reviewed the literature and selected studies that report an association among H. pylori detections in the oral cavity (dental plaque, saliva, tongue, tonsil tissue, root canals, oral mucosa) in humans and in animals, as well as in the human stomach. The oral cavity may be considered the main reservoir for H. pylori. There are a correlations between H. pylori infection in the oral cavity and periodontal disease, oral tissue inflammation, H. pylori transmission, and gastric reinfection. We believe that the mouth is a reservoir and that it plays a crucial role in both H. pylori transmission and gastric infection.

Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background

Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of the TNF-α gene.

Methods

One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2^-ΔΔCT).

Results

The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression.

Conclusions

Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α pathway may play an important role in the progression from gastritis to gastric cancer

Differential expression of histone deacetylase and acetyltransferase genes in gastric cancer and their modulation by trichostatin A

Gastric cancer is still the second leading cause of cancer-related death worldwide, even though its incidence and mortality have declined over the recent few decades. Epigenetic control using histone deacetylase inhibitors, such as trichostatin A (TSA), is a promising cancer therapy. This study aimed to assess the messenger RNA (mRNA) levels of three histone deacetylases (HDAC1, HDAC2, and HDAC3), two histone acetyltransferases (GCN5 and PCAF), and two possible targets of these histone modifiers (MYC and CDKN1A) in 50 matched pairs of gastric tumors and corresponding adjacent nontumors samples from patients with gastric adenocarcinoma, as well as their correlations and their possible associations with clinicopathological features. Additionally, we evaluated whether these genes are sensitive to TSA in gastric cancer cell lines. Our results demonstrated downregulation of HDAC1, PCAF, and CDKN1A in gastric tumors compared with adjacent nontumors (P < 0.05). On the other hand, upregulation of HDAC2, GCN5, and MYC was observed in gastric tumors compared with adjacent nontumors (P < 0.05). The mRNA level of MYC was correlated to HDAC3 and GCN5 (P < 0.05), whereas CDKN1A was correlated to HDAC1 and GCN5 (P < 0.05 and P < 0.01, respectively). In addition, the reduced expression of PCAF was associated with intestinal-type gastric cancer (P = 0.03) and TNM stages I/II (P = 0.01). The increased expression of GCN5 was associated with advanced stage gastric cancer (P = 0.02) and tumor invasion (P = 0.03). The gastric cell lines treated with TSA showed different patterns of histone deacetylase and acetyltransferase mRNA expression, downregulation of MYC, and upregulation of CDKN1A. Our findings suggest that alteration of histone modifier genes play an important role in gastric carcinogenesis, contributing to MYC and CDKN1A deregulation. In addition, all genes studied here are modulated by TSA, although this modulation appears to be dependent of the genetic background of the cell line.

Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Background

Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.

Results

Patients with gastritis tested positive for H. pylori more frequently. The dupA gene was detected in 41.5% of them (85/205); cagA gene was found in 98 isolates (47.8%) and vacA genotype s1/m1 in 50.2%, s1/m2 in 8.3%, s2/m2 in 36.6%, s2/m1 in 0.5% and s1/s2/m1/m2 in 4.4%. We also verified a significant association between cagA and dupA genes [p = 0.0003, relative risk (RR) 1.73 and confidence interval [CI] = 1.3–2.3]. The genotypes s1/m1 were also associated with dupA gene (p = 0.0001, RR: 1.72 and CI: 1.3–2.2). The same associations were found when analyzing pediatric and adult groups of patients individually.

Conclusion

Ours results suggest that dupA is highly frequent in Brazilian patients and is associated with cagA gene and vacA s1/m1 genotype, and it may be considered an important virulence factor in the development of gastric diseases in adults or children.

Exercise reduces angiotensin II responses in rat femoral veins

The control of blood flow during exercise involves different mechanisms, one of which is the activation of the renin-angiotensin system, which contributes to exercise-induced blood flow redistribution. Moreover, although angiotensin II (Ang II) is considered a potent venoconstrictor agonist, little is known about its effects on the venous bed during exercise. Therefore, the present study aimed to assess the Ang II responses in the femoral vein taken from sedentary and trained rats at rest or subjected to a single bout of exercise immediately before organ bath experiments. Isolated preparations of femoral veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in an organ bath. In parallel, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as the ETA and ETB receptors, was quantified by real-time PCR in this tissue. The results show that, in the presence of L-NAME, Ang II responses in resting-sedentary animals were higher compared to the other groups. However, this difference disappeared after co-treatment with indomethacin, BQ-123 or BQ-788. Moreover, exercise reduced ppET-1 mRNA expression. These reductions in mRNA expression were more evident in resting-trained animals. In conclusion, either acute or repeated exercise adapts the rat femoral veins, thereby reducing the Ang II responses. This adaptation is masked by the action of locally produced nitric oxide and involves, at least partially, the ETB- mediated release of vasodilator prostanoids. Reductions in endothelin-1 production may also be involved in these exercise-induced modifications of Ang II responses in the femoral vein.

Association analysis between K and -116A variants of butyrylcholinesterase and Alzheimer's disease in a Brazilian population

In Alzheimer's disease (AD) a reduction in acetylcholinesterase (AChE) and an increase in butyrylcholinesterase (BChE) activity are observed. K variant (539T) is the most common variant of the BCHE gene and, although controversial, several studies reported association between K variant and AD. Previous results showed that the K variant alone is not capable of diminishing BChE activity, depending on the presence of the -116A variant. Considering that, we conducted a case-control association study using a clinically well defined group of AD patients (n = 82) and age and sex matched control subjects (EC; n = 78) in order to test the association with these variations of BCHE gene in a Brazilian population. The allele, genotype and haplotype frequencies of the K and the -116A variants of BCHE gene were not significantly different between cases and controls. Although not reaching statistical significance, the results suggested that the presence of -116A variant may have a protective effect against AD. The association of the K variant with AD in a controversial manner in different surveys is probably caused by its linkage disequilibrium with -116A that, by reducing BChE activity, potentially increases cholinergic transmission in comparison with usual genotypes.

SORL1 and SIRT1 mRNA expression and promoter methylation levels in aging and Alzheimer's Disease

Alzheimer's Disease (AD) is a neurodegenerative disorder and the most common cause of dementia among the elderly. Efforts have been made to understand the genetic and epigenetic mechanisms involved in the development of this disease. As SORL1 (sortilin-related receptor) and SIRT1 (sirtuin 1) genes have been linked to AD pathogenesis, we aimed to investigate their mRNA expression and promoter DNA methylation in post mortem brain tissues (entorhinal and auditory cortices and hippocampus) from healthy elderly subjects and AD patients. We also evaluated these levels in peripheral blood leukocytes from young, healthy elderly and AD patients, investigating whether there was an effect of age on these profiles. The comparative CT method by Real Time PCR and MALDI-TOF mass spectrometry were used to analyze gene expression and DNA methylation, respectively. SORL1 gene was differently expressed in the peripheral blood leukocytes and might act as a marker of aging in this tissue. Furthermore, we found that SORL1 promoter DNA methylation might act as one of the mechanisms responsible for the differences in expression observed between blood and brain for both healthy elderly and AD patients groups. The impact of these studied genes on AD pathogenesis remains to be better clarified.

Analysis of SNAP25 mRNA expression and promoter DNA methylation in brain areas of Alzheimer's Disease patients

Alzheimer's Disease (AD) is the most common cause of dementia in elderly people. The presynaptic terminal is an important site of pathological changes in AD, leading to synaptic loss in specific brain regions, such as in the cortex and hippocampus. In this study, we investigated synaptosomal-associated protein, 25-kDa (SNAP25) mRNA levels and promoter DNA methylation in post mortem brain tissues (entorhinal and auditory cortices and hippocampus) from healthy elderly and AD subjects as well as in peripheral blood leukocytes of young, healthy elderly and AD patients. mRNA quantification was performed by quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) using the ΔΔC(T) method and promoter DNA methylation was quantified by mass spectrometry using the Sequenom EpiTYPER platform. We observed a significant decrease in SNAP25 expression in AD across all the three brain regions in relation to the healthy elderly subjects, suggesting impairment in synaptic function. The changes in the auditory cortex reflected those observed in the hippocampus and entorhinal cortex, the primary areas affected in AD. However, no AD-associated differences in SNAP25 promoter DNA methylation were observed suggesting that other mechanisms may be involved in mediating the observed gene expression changes.

Interleukin-8-251T > A, Interleukin-1α-889C > T and Apolipoprotein E polymorphisms in Alzheimer's disease

An inflammatory process has been involved in numerous neurodegenerative disorders such as Parkinson’s disease, stroke and Alzheimer’s disease (AD). In AD, the inflammatory response is mainly located in the vicinity of amyloid plaques. Cytokines, such as interleukin-8 (IL-8) and interleukin-1α (IL-1α), have been clearly involved in this inflammatory process. Polymorphisms of several interleukin genes have been correlated to the risk of developing AD. The present study investigated the association of AD with polymorphisms IL-8 -251T > A (rs4073) and IL-1α-889C > T (rs1800587) and the interactive effect of both, adjusted by the Apolipoprotein E genotype. 199 blood samples from patients with AD, 146 healthy elderly controls and 95 healthy young controls were obtained. DNA samples were isolated from blood cells, and the PCR-RFLP method was used for genotyping. The genotype distributions of polymorphisms IL-8, IL-1α and APOE were as expected under Hardy-Weinberg equilibrium. The allele frequencies did not differ significantly among the three groups tested. As expected, the APOE4 allele was strongly associated with AD (p < 0.001). No association of AD with either the IL-1α or the IL-8 polymorphism was observed, nor was any interactive effect between both polymorphisms. These results confirm previous studies in other populations, in which polymorphisms IL-8 -251T > A and IL-1α-889C > T were not found to be risk factors for AD.

Cytogenetic effect of 5-azacytidine in patients with hematological malignancies

Background

Recently, the importance of cytogenetics has grown in the diagnosis, prognosis and treatment of leukemias and myelodysplastic syndromes. 5-azacytidine is a drug that has well-known cytogenetical effects and is approved in the treatment of myelodysplastic syndromes. To date, no studies have been performed to evaluate the impact of 5-azacytidine on the chromosomes of patients with hematological neoplasias. This study aimed to investigate the effects of 5-azacytidine on chromosomes of patients with different hematological malignancies using G-band analyses to identify possible cytogenetical alterations.

Methods

The peripheral blood of 18 patients with hematological malignancies and 18 controls was collected in heparinized tubes. 5-azacytidine was added, at a final concentration of 10-5M, to cultures 7 hours prior to harvest.

Results

Uncoiled centromeric/pericentromeric heterochromatin of chromosomes-1, 9 and 16 occurred more frequently in the patients than in controls. This higher frequency of uncoiled heterochromatin was statistically significant (p-value = 0.004) for chromosome-9. Conversely, we observed that the fragile site at 19q13 was more frequent in controls (p-value = 0.0468).

Conclusions

The results of this study suggest that satellite sequences, located in the heterochromatin of chromosome-9, are hypomethylated in hematological malignancies. This hypomethylation may contribute to the disease, activating transposable elements and/or promoting genomic instability, enabling the loss of heterozygosity of important tumor suppressor genes. An investigation of the 19q13 region may help to understand whether or not the predominant occurrence of the fragile site at 19q13 in controls is due to hypermethylation of this region.

TP53 codon 72 polymorphism as a risk factor for cardiovascular disease in a Brazilian population

TP53, a tumor suppressor gene, has a critical role in cell cycle, apoptosis and cell senescence and participates in many crucial physiological and pathological processes. Identification of TP53 polymorphism in older people and age-related diseases may provide an understanding of its physiology and pathophysiological role as well as risk factors for complex diseases. TP53 codon 72 (TP53:72) polymorphism was investigated in 383 individuals aged 66 to 97 years in a cohort from a Brazilian Elderly Longitudinal Study. We investigated allele frequency, genotype distribution and allele association with morbidities such as cardiovascular disease, type II diabetes, obesity, neoplasia, low cognitive level (dementia), and depression. We also determined the association of this polymorphism with serum lipid fractions and urea, creatinine, albumin, fasting glucose, and glycated hemoglobin levels. DNA was isolated from blood cells, amplified by PCR using sense 5'-TTGCCGTCCCAAGCAATGGATGA-3' and antisense 5'-TCTGGGAAGGGACAGAAGATGAC-3' primers and digested with the BstUI enzyme. This polymorphism is within exon 4 at nucleotide residue 347. Descriptive statistics, logistic regression analysis and Student t-test using the multiple comparison test were used. Allele frequencies, R (Arg) = 0.69 and P (Pro) = 0.31, were similar to other populations. Genotype distributions were within Hardy-Weinberg equilibrium. This polymorphism did not show significant association with any age-related disease or serum variables. However, R allele carriers showed lower HDL levels and a higher frequency of cardiovascular disease than P allele subjects. These findings may help to elucidate the physiopathological role of TP53:72 polymorphism in Brazilian elderly people.

CagA positive Helicobacter pylori in Brazilian children related to chronic gastritis

Helicobacter pylori is a spiral-shaped Gram-negative bacterium. It colonizes the gastric mucosa of humans and persists for decades if not treated. Helicobacter pylori infection affects more than half of the world's population and invariably results in chronic gastritis. The cagA gene is present in about 60 to 70% of H. pylori strains; it encodes a high-molecular-weight protein (120 to 140 kDa) and several investigators have noted a correlation between strains that possess cagA and the severity of gastric mucosal inflammation. We examined the relation between cagA status in H. pylori strains and chronic gastritis with inflammatory processes in children from Marília, São Paulo, Brazil. One-hundred-twenty-one children were analyzed histopathologically and by polymerase chain reaction (PCR) to detect H. pylori and cagA. We then looked for an association between cagA presence and inflammatory infiltration. Using histology and PCR, we found 47% H. pylori positive infection; 29 children were diagnosed with chronic gastritis, while 28 showed normal mucosa by histopathological analysis. CagA presence was genotyped in both groups, and an inflammatory infiltrate was studied in all infected children with chronic gastritis. We found cagA strains in 20 of 29 (69%) children with chronic gastritis and 18 of 28 (64%) with normal mucosa, demonstrating a strong relationship between the strains and the inflammatory process. We found a positive association between an inflammatory process associated with H. pylori of cagA+ strains and chronic gastritis development.

Promoter methylation analysis of SIRT3, SMARCA5, HTERT and CDH1 genes in aging and Alzheimer's disease

Longevity related genes were investigated concerning promoter methylation. SIRT3, SMARCA5, HTERT and CDH1 promoters were analyzed in peripheral blood in relation to gender, age and Alzheimer's disease (AD). Methylation Specific PCR assay (MSP) was used. There were no significant differences in methylation frequencies of SIRT3, SMARCA5 and CDH1 among young, elderly and AD groups (p> 0.05), showing no association with aging or AD. On the other hand, HTERT methylation frequency was associated with the aging process, in that AD patients differed from elderly controls (p=0.0086), probably due to telomere and immune dysfunctions involved in AD pathogenesis.

Apolipoprotein A-V gene polymorphism -1131T>C and Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly and is also considered a progeroid genetic syndrome. The etiology of AD is complex and the mechanisms underlying its pathophysiology remain to be clarified. It has been suggested that a high serum cholesterol level is a risk factor for (AD), and that some polymorphisms of genes encoding proteins regulating cholesterol metabolism are associated with AD development. APOA5 is a recently discovered apolipoprotein involved primarily with triglyceride (TG) metabolism disorder. This study investigates the association of AD with the APOA5 gene -1131T>C polymorphisms in samples of 106 patients with Alzheimer's disease (AD), 76 elderly healthy controls and 93 young healthy controls. DNA samples were isolated from blood cells, amplified by PCR and digested with Tru1l. We observed that the genotype distributions of APOA5 variants were within Hardy-Weinberg equilibrium in all subject samples. Furthermore, chi-square test comparison for genotype distributions and allele frequencies did not reveal any significant difference among the three groups of subjects P>0.05). These results support the idea that these variants are not involved as a risk factor for developing AD.

Association of lipase lipoprotein polymorphisms with myocardial infarction and lipid levels

BACKGROUND

Lipoprotein lipase has an important role in lipid metabolism. Elevated levels of very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) are associated with increased risk of coronary artery disease and low levels of high-density lipoprotein (HDL) are potentially atherogenic. The HindIII and S447X polymorphisms of the lipoprotein lipase (LPL) gene are associated with cardiovascular disease in some populations.

METHODS

LPL HindIII and S447X polymorphisms were analyzed in 343 individuals of 66-97 years of age from a cohort of a Brazilian elderly longitudinal study. Allele frequencies, genotype distribution and allele association with major morbidities and with serum lipid, urea, creatinine and albumin levels were also investigated. The whole sample was genotyped by PCR-restriction fragment length polymorphism (RFLP). Descriptive statistics, logistic regression analysis and t-test were used.

RESULTS

Allele frequencies were H(+)=0.652 and H(-)=0.348 for LPL HindIII and S=0.824 and X=0.176 for LPL S447X polymorphism. Both polymorphisms have frequencies similar to those in some European populations. LPL HindIII polymorphism showed significant association of the H(+) allele with myocardial infarction. The H(-) allele showed a tendency to associate with higher HDL levels. The LPL S447X S allele was associated with higher triglyceride levels.

CONCLUSIONS

These findings may help to identify risk factors for subjects and families and clarify the physiopathological role of these polymorphisms in age-related diseases.

Prevalence of Helicobacter pylori cagA, iceA and babA2 alleles in Brazilian patients with upper gastrointestinal diseases

Helicobacter pylori is an important human pathogen associated with gastrointestinal diseases such as gastritis, gastric and duodenal ulcer (peptic ulcer disease, PUD), and gastric cancer. A number of pathogenic factors have been described for this bacterium, and some of them have been proposed as markers for the prediction of the clinical outcome. However, with the exception of the cag and vacA status, there is no universal consensus regarding the importance of the other virulence factors. Therefore, the aim of this study was to investigate the status of H. pylori strains regarding the babA and iceA alleles, as well as the cagA genotype, to reveal any association between these genotypes and clinical outcomes in Brazilian patients. The great majority (92.6%) of the strains were typed as iceA1, while 40.4% were found to possess the babA2 allele. The cagA gene was detected in 73.4% of the strains. The iceA2 and cagA genotypes were associated with PUD, while iceA1 was negatively correlated with PUD. However, considering the high percentage of strains typed as iceA1, these associations must be treated with caution. No clinical entity was associated with the babA2 allele. These results suggest that iceA1 is not a good marker for the diseases associated with H. pylori infection in Brazil. Further studies are needed in order to elucidate the relevance of the babA status, because other studies performed in Brazil have associated the babA2 allele with clinical outcomes. These results also indicate the existence of regional differences in the H. pylori genotypes and their association with clinical outcomes.

cagA vacA alelles and babA2 genotypes of Helicobacter pylori associated with gastric disease in Brazilian adult patients

Helicobacter pylori is an important human pathogen that causes chronic gastritis and is associated with development of peptic ulcer disease and gastric malignancies. The vacuolating cytotoxin (vacA), cagA gene, and babA2 gene are important virulence factor involving gastric diseases. Eighty-nine Helicobacter pylori-positive gastric biopsies were analyzed by polymerase chain reaction and Southern blotting for H. pylori detection and genotyping with primer pairs from each virulence gene. Fifty-three strains (59%) were common vacA genotype s1/m1, and only 14 (16%) were s2/m2, 12% of strains was found to have multiple infection. The cagA presence was detected in 48% (43 strains) and babA2 gene was detected in 44% of our H. pylori strains. We observed high percentage of s1/m1 strains with chronic gastritis and peptic ulcer and a significant correlation between cagA presence with the s1 allele and babA2 gene with chronic gastritis.

Frequency of Werner helicase 1367 polymorphism and age-related morbidity in an elderly Brazilian population

Werner syndrome (WS) is a premature aging disease caused by a mutation in the WRN gene. The gene was identified in 1996 and its product acts as a DNA helicase and exonuclease. Some specific WRN polymorphic variants were associated with increased risk for cardiovascular diseases. The identification of genetic polymorphisms as risk factors for complex diseases affecting older people can improve their prevention, diagnosis and prognosis. We investigated WRN codon 1367 polymorphism in 383 residents in a district of the city of São Paulo, who were enrolled in an Elderly Brazilian Longitudinal Study. Their mean age was 79.70 +/- 5.32 years, ranging from 67 to 97. This population was composed of 262 females (68.4%) and 121 males (31.6%) of European (89.2%), Japanese (3.3%), Middle Eastern (1.81%), and mixed and/or other origins (5.7%). There are no studies concerning this polymorphism in Brazilian population. These subjects were evaluated clinically every two years. The major health problems and morbidities affecting this cohort were cardiovascular diseases (21.7%), hypertension (83.7%), diabetes (63.3%), obesity (41.23%), dementia (8.0%), depression (20.0%), and neoplasia (10.8%). Their prevalence is similar to some urban elderly Brazilian samples. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. Allele frequencies were 0.788 for the cysteine and 0.211 for the arginine. Genotype distributions were within that expected for the Hardy-Weinberg equilibrium. Female gender was associated with hypertension and obesity. Logistic regression analysis did not detect significant association between the polymorphism and morbidity. These findings confirm those from Europeans and differ from Japanese population.

Telomeres on chromosome 21 and aging in lymphocytes and gingival fibroblasts from individuals with Down syndrome

Progressive chromosome 21 loss in individuals with trisomy 21 or Down syndrome (DS) is supposedly related to their premature senescence. In addition, the telomere hypothesis of cellular aging involving telomere shortening in normal and accelerated aging in vivo and in vitro is well documented. This study investigated the integrity of two chromosome 21 regions (the 21q telomere and the 21q22.13-q22.2 region) and their relationship with aging by means of fluorescence in situ hybridization (FISH) in lymphocytes and gingival fibroblasts cells. The use of tissues from different germ layers allows detection of mosaicism. Chromosome variations in tissue from the neuroectoderm layer could explain the variable phenotype of DS. This approach is original in the literature. Lymphocyte and gingival fibroblast nuclei from 18 affected individuals aged 5-54 years were analyzed. Although not significant (P = 0.06), analysis from 11 tissue-matched individuals as well as the comparison between lymphocytes and fibroblasts from different subjects (P = 0.05) suggested that lymphocyte cells are more likely to miss 21q telomere signals. Hence, gingival fibroblasts are probably capable of more efficient cell repair, and the occurrence of mosaicism is more related to cell proliferation than to germ layer origin. Investigation of the 21q22.13-q22.2 region from six tissue-matched individuals and from different DS patients revealed no significant differences between the tissues.

Werner helicase polymorphism is not associated with Alzheimer's disease

Alzheimer disease (AD) is the most common neurodegenerative disorder in the elderly and is also considered a progeroid genetic syndrome. The etiology of AD is complex and the mechanisms underlying its pathophysiology remains to be clarified. Werner syndrome (WS) is a rare autosomal recessive disorder characterized as a segmental progeroid syndrome. The gene (WRN) was recently identified. Its product acts as a DNA helicase and exonuclease. This study investigates the association of AD with the WRN 1367 polymorphisms in samples of 67 DA patients, 56 elderly healthy and 66 young healthy controls. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. We observed that the genotype distributions of WRN 1367 variants were within Hardy-Weinberg equilibrium in all subject samples. Furthermore, chi-square test comparison for genotype distributions and allele frequencies did not reveal any significant difference among the three groups of subjects (P>0.05). These results support the idea that these variants are not involved as a risk factor for developing AD.

Apolipoprotein E4 allele and ribosomal genes in Alzheimer's disease

Ribosomal genes are involved in cellular transcription, translation and gene expression modulation process. An association between 28S/18S rRNA ratio levels with apoptosis and aging has been reported. Moulder et al. [22] and Hashimoto et al. [8] showed an association between apolipoprotein E4 allele and neuronal cell apoptosis through diverse mechanisms. The apoE 4 allele is considered a late-onset Alzheimer's disease (AD) risk factor associated with AD pathogenesis. We evaluated the association between apoE4 allele genotyping by PCR and rRNA 28S/18S ratio by slot blotting technique using peripheral blood samples of 18 Alzheimer's disease patients, 18 elderly controls and 18 young controls. A rRNA ratio decrease was observed in AD individuals confirming our previous results but this association is independently of the ApoE4 allele genotype. Thus our results pointed that two different mechanisms are involved in the etiology of Alzheimer disease each one leading independently to cell death. Further studies could investigate these factors.