Association between INDELs in MicroRNAs and Susceptibility to Gastric Cancer in Amazonian Population

Gastric cancer (GC) is a multifactorial, complex, and aggressive disease with a prevalence of one million new cases and high global mortality. Factors such as genetic, epigenetic, and environmental changes contribute to the onset and progression of the disease. Identification of INDELs in miRNA and its target sites in current studies showed an important role in the development of cancer. In GC, miRNAs act as oncogenes or tumor suppressors, favoring important cancer pathways, such as cell proliferation and migration. This work aims to investigate INDELs in the coding region of miRNAs (hsa-miR-302c, hsa-miR-548AJ-2, hsa-miR-4274, hsa-miR-630, hsa-miR-516B-2, hsa-miR-4463, hsa-miR-3945, hsa-miR-548H_4, hsa-miR-920, has-mir-3171, and hsa-miR-3652) that may be associated with susceptibility and clinical variants of gastric cancer. For this study, 301 patients with GC and 145 individuals from the control group were selected from an admixed population in the Brazilian Amazon. The results showed the hsa-miR-4463, hsa-miR-3945, hsa-miR-548H_4, hsa-miR-920 and hsa-miR-3652 variants were associated with gastric cancer susceptibility. The hsa-miR-4463 was significantly associated with clinical features of GC such as diffuse gastric tumor histological type, "non-cardia" localization region, and early onset. Our findings indicated that INDELs could be potentially functional genetic variants for gastric cancer risk.

Effects of alkaline water intake on gastritis and miRNA expression (miR-7, miR-155, miR-135b and miR-29c)

It is known that abnormal expression of miRNAs in the gastric cancer (GC) contributes to its carcinogenesis. Therefore, ingestion of commercial (usual) water on a daily basis may be a contributing factor for the occurrence of alterations in the gastric mucosal. In this study, it was evaluated the expression of the miRNAs miR-29c, miR-7, miR-155, and miR-135b in the gastric tissue of patients with gastritis before and after the consumption of alkaline water (pH range from 8.0 to 10.0), as well as the clinic pathological characteristics.

METHODS

50 subjects from the Amazon region, diagnosed with gastritis that routinely used commercial (usual) water with a pH lower than 5.0, were enrolled to change the consume water to a pH of 8.5 to 10.0 for 5 months.

RESULTS

Endoscopic findings of gastritis were such different (less severe disease), P = 0.024; in 43% diagnosed with moderate gastritis upfront esophagogastroduodenoscopy (EGD) presented mild gastritis after the consumption of alkaline water, according to study methods; there were no worsening gastritis and there were a significant increase in the expression of miR-135b (P = 0.039) and miR-29c (P = 0.039).

CONCLUSION

Modified pH range water (from 8.0 to 10.0) ingested for 5 months was able lead to a less severe gastritis according to the Sidney classification system, suggesting that this lifestyle change represented a clinical benefit in patients with gastritis on the Amazon region. In addition, higher expression of miR-135b and miR-29c was observed after the consumption of alkaline water for 5 months.

High-Throughput miRNA Sequencing Reveals a Field Effect in Gastric Cancer and Suggests an Epigenetic Network Mechanism

Field effect in cancer, also called "field cancerization", attempts to explain the development of multiple primary tumors and locally recurrent cancer. The concept of field effect in cancer has been reinforced, since molecular alterations were found in tumor-adjacent tissues with normal histopatho-logical appearances. With the aim of investigating field effects in gastric cancer (GC), we conducted a high-throughput sequencing of the miRnome of four GC samples and their respective tumor-adjacent tissues and compared them with the miRnome of a gastric antrum sample from patients without GC, assuming that tumor-adjacent tissues could not be considered as normal tissues. The global number of miRNAs and read counts was highest in tumor samples, followed by tumor-adjacent and normal samples. Analyzing the miRNA expression profile of tumor-adjacent miRNA, hsa-miR-3131, hsa-miR-664, hsa-miR-483, and hsa-miR-150 were significantly downregulated compared with the antrum without tumor tissue (P-value < 0.01; fold-change <5). Additionally, hsa-miR-3131, hsa-miR-664, and hsa-miR-150 were downregulated (P-value < 0.001) in all paired samples of tumor and tumor-adjacent tissues, compared with antrum without tumor mucosa. The field effect was clearly demonstrated in gastric carcinogenesis by an epigenetics-based approach, and potential biomarkers of the GC field effect were identified. The elevated expression of miRNAs in adjacent tissues and tumors tissues may indicate that a cascade of events takes place during gastric carcinogenesis, reinforcing the notion of field effects. This phenomenon seems to be linked to DNA methylation patterns in cancer and suggests the involvement of an epigenetic network mechanism.

High-Throughput Sequencing of miRNAs Reveals a Tissue Signature in Gastric Cancer and Suggests Novel Potential Biomarkers

Gastric cancer has a high incidence and mortality rate worldwide; however, the use of biomarkers for its clinical diagnosis remains limited. The microRNAs (miRNAs) are biomarkers with the potential to identify the risk and prognosis as well as therapeutic targets. We performed the ultradeep miRnomes sequencing of gastric adenocarcinoma and gastric antrum without tumor samples. We observed that a small set of those samples were responsible for approximately 80% of the total miRNAs expression, which might represent a miRNA tissue signature. Additionally, we identified seven miRNAs exhibiting significant differences, and, of these, hsa-miR-135b and hsa-miR-29c were able to discriminate antrum without tumor from gastric cancer regardless of the histological type. These findings were validated by quantitative real-time polymerase chain reaction. The results revealed that hsa-miR-135b and hsa-miR-29c are potential gastric adenocarcinoma occurrence biomarkers with the ability to identify individuals at a higher risk of developing this cancer, and could even be used as therapeutic targets to allow individualized clinical management.

Typical and atypical enteropathogenic Escherichia coli bacterial translocation associated with tissue hypoperfusion in rats

Although enteropathogenic Escherichia coli (EPEC) are well-recognized diarrheal agents, their ability to translocate and cause extraintestinal alterations is not known. We investigated whether a typical EPEC (tEPEC) and an atypical EPEC (aEPEC) strain translocate and cause microcirculation injury under conditions of intestinal bacterial overgrowth. Bacterial translocation (BT) was induced in female Wistar-EPM rats (200-250 g) by oroduodenal catheterization and inoculation of 10 mL 10(10) colony forming unit (CFU)/mL, with the bacteria being confined between the duodenum and ileum with ligatures. After 2 h, mesenteric lymph nodes (MLN), liver and spleen were cultured for translocated bacteria and BT-related microcirculation changes were monitored in mesenteric and abdominal organs by intravital microscopy and laser Doppler flow, respectively. tEPEC (N = 11) and aEPEC (N = 11) were recovered from MLN (100%), spleen (36.4 and 45.5%), and liver (45.5 and 72.7%) of the animals, respectively. Recovery of the positive control E. coli R-6 (N = 6) was 100% for all compartments. Bacteria were not recovered from extraintestinal sites of controls inoculated with non-pathogenic E. coli strains HB101 (N = 6) and HS (N = 10), or saline. Mesenteric microcirculation injuries were detected with both EPEC strains, but only aEPEC was similar to E. coli R-6 with regard to systemic tissue hypoperfusion. In conclusion, overgrowth of certain aEPEC strains may lead to BT and impairment of the microcirculation in systemic organs.

Study of the usefulness of optic fundi examination of patients with hypertension in a clinical setting

The purpose of this study was to evaluate the usefulness of direct opthalmoscopy by non-opthalmologists in patients with hypertension. In a cross-sectional survey, we analysed the association between optic fundi abnormalities, individually and according to the criteria of Keith and Wagener (KW), with blood pressure and duration of known hypertension in 400 non-diabetic hypertensive patients. The optic fundi abnormalities were more frequent in patients with diastolic blood pressure (DBP) > 105 mm Hg (P = 0.002), SBP > 180 mm Hg (P < 0.0001) and with a duration of known hypertension > 3 years (P = 0.002). The severity of hypertension did not vary in parallel with the KW classes I and II: 34.5% of patients classified as KW I had a diastolic pressure of > 105 mm Hg compared with only 25.3% of those classified as KW II. Class III abnormalities were infrequent (2.5% of the whole cohort). In a logistic regression model, diffuse arteriolar narrowing was associated with DBP (P = 0.002) and age (P < 0.001). Abnormalities of the arteriovenous crossings were associated with SBP (P = 0.001) and duration of disease (P = 0.008). The positive predictive value of any fundoscopic abnormality to estimate the severity of hypertension was 59% and the negative value was 60%. The results of this study demonstrate that optic fundi examination by internists and cardiologists does not give an accurate assessment of the severity of hypertension in most patients, and that the Keith-Wagener classification of retinopathy has a limited applicability.(ABSTRACT TRUNCATED AT 250 WORDS)