Thiago Simão Gomes

Receptor-Induced Dilatation in the Systemic and Intrarenal Adaptation to Pregnancy in Rats

Normal pregnancy is associated with systemic and intrarenal vasodilatation resulting in an increased glomerular filtration rate. This adaptive response occurs in spite of elevated circulating levels of angiotensin II (Ang II). In the present study, we evaluated the potential mechanisms responsible for this adaptation. The reactivity of the mesangial cells (MCs) cultured from 14-day-pregnant rats to Ang II was measured through changes in the intracellular calcium concentration ([Cai]). The expression levels of inducible nitric oxide synthase (iNOS), the Ang II-induced vasodilatation receptor AT2, and the relaxin (LGR7) receptor were evaluated in cultured MCs and in the aorta, renal artery and kidney cortex by real time-PCR. The intrarenal distribution of LGR7 was further analyzed by immunohistochemistry. The MCs displayed a relative insensitivity to Ang II, which was paralleled by an impressive increase in the expression level of iNOS, AT2 and LGR7. These results suggest that the MCs also adapt to the pregnancy, thereby contributing to the maintenance of the glomerular surface area even in the presence of high levels of Ang II. The mRNA expression levels of AT2 and LGR7 also increased in the aorta, renal artery and kidney of the pregnant animals, whereas the expression of the AT1 did not significantly change. This further suggests a role of these vasodilatation-induced receptors in the systemic and intrarenal adaptation during pregnancy. LGR7 was localized in the glomeruli and on the apical membrane of the tubular cells, with stronger labeling in the kidneys of pregnant rats. These results suggest a role of iNOS, AT2, and LGR7 in the systemic vasodilatation and intrarenal adaptation to pregnancy and also suggest a pivotal role for relaxin in the tubular function during gestation.

The intrinsic apoptotic signaling pathway in gastric adenocarcinomas of Brazilian patients: Immunoexpression of the Bcl-2 family (Bcl-2, Bcl-x, Bak, Bax, Bad) determined by tissue microarray analysis

This study was undertaken to investigate the immunoexpression of Bcl-2 family proteins (Bcl-2, Bcl-x, Bax, Bak and Bad) and to evaluate the correlation between the immunoexpression of these proteins and that of cleaved caspase 3, Ki-67 and p53. A tissue microarray (TMA) paraffin block was constructed using gastric carcinoma tissue (test group) and adjacent normal gastric mucosa (control group) from 87 patients who had not previously undergone radiotherapy or chemotherapy. Sections from the TMA block (4 µm) were subjected to immunohistochemistry for Bcl-2, Bcl-x, Bax, Bak, Bad, p53, Ki-67 and cleaved caspase-3. The slides were evaluated by the semi-quantitative method, and the scores obtained (intensity vs. percentage of staining) were correlated with one another and with the apoptotic index, cellular proliferation and data regarding patient survival. The studied proteins were present in the tumor tissue and in the normal gastric mucosa, but at different intensities and with differences in the number of positive cells. There was an association between tumor size and p53 expression, and intestinal type adenocarcinoma was positively correlated with the expression of Bax, Bad and Ki-67. The immunoexpression of Bcl-x, Bak, Bad, p53 and Ki-67 showed statistically significant differences between the tumor tissue and the adjacent normal gastric mucosa. There was an association between the expression of Bax, Bak and Bad in the normal gastric mucosa. No correlation between patient survival and the expression of these proteins was observed. Overexpression of the Bcl-x protein in the adenocarcinomas and the difference in Bcl-x expression between the test and the control group may be related to the anti-apoptotic effect of this protein. The reduced expression of Bak and Bad and the increased expression of p53 and Ki-67 in the adenocarcinomas demonstrate the imbalance between apoptosis and cellular proliferation, which results in uncontrolled tumor cell proliferation.

HSP27 is Commonly Expressed in Cervical Intraepithelial Lesions of Brazilian Women

Heat shock proteins are molecular chaperones that may be constitutively present in cells protecting them from various stresses, such as extreme temperature, anoxia or chemical agents. Cervical cancer is the second most prevalent malignancy of women. In this study, we analyzed the expression of Hsp27 by immunohistochemistry in cervical intraepithelial lesions of Brazilian women, along with samples from non neoplasic lesions (NN). Cervical intraepithelial neoplasia I (CIN I), II (CIN II) and III (CIN III)/in situ carcinoma and squamous cell carcinoma (SCC) were included. Immunostaining was observed in 30 (100%) samples of NN, 46 (92%) in CIN I, 50 (100%) in CIN II, 52 (98.11%) in CIN III/CIS, and 46 (98.11%) in SCC. In group NN Hsp27 immunostaining was heterogeneous, more intense in basal and parabasal layers of the epithelium and less or absent in the intermediate and superficial layer. The majority of the samples of CIS and SCC presented strong staining in allepithelial layers. Metaplasic cells, when present, were strongly stained. In this study, Hsp27 protein was found to be commonly expressed in cervical epithelial cells.

Correlation analysis of c-myc, p21(WAF/CIP1), p53, C-erbB-2 and COX-2 proteins in esophageal squamous cell carcinoma.

Esophageal cancer is one of the most frequently occurring malignancies and the seventh leading cause of cancer-related deaths in the world. Esophageal squamous cell carcinoma (ESCC) is the most common histological type of esophageal cancer worldwide. Our goal in this study was to detect c-myc, p21(WAF/CIP1), p53, C-erbB-2 and COX-2 immuno-expression in ESCC. Archival formalin-fixed, paraffin-embedded tissues of 18 cases of ESCC (13 biopsies and 5 surgical specimens) were studied, retrospectively, by immunohistochemistry. p53 protein was observed in 50% of the cases, while c-myc was found in 6 of 18 samples (33.33%). All samples (100%) were negative for p21(WAF/CIP1). C-erbB-2 oncoprotein and the COX-2 protein were detected in 5.5% (1/18) and 16.66% (3/18) of the cases, respectively. Taken together, our results suggest that c-myc, p53, C-erbB-2 and COX-2 proteins do not correlate with cancer stage or follow-up in ESCC as revealed by immunohistochemistry.

The extrinsic apoptotic signaling pathway in gastric adenocarcinomas assessed by tissue microarray

The purpose of this investigation was to analyze the immunoexpression of FasL, Fas, FADD, cleaved caspase 8, and cleaved caspase 3 in gastric cancer. Formalin-fixed and paraffin-embedded gastric adenocarcinoma tissues from 87 patients, including adjacent normal tissues, were included on tissue microarray by immunohistochemistry. The tumor and the adjacent normal tissues were positive for FasL in 66.7% and 90.6%, for Fas in 52.8% and 52.4%, for FADD in 67.4% and 82.3%, for cleaved caspase 8 in 27.9% and 37.7%, and for cleaved caspase 3 in 33.7% and 8.3%, respectively. FasL and the FADD from tumor were statistically different in relation to the histological type. Cleaved caspase 8 was statistically different in relation to clinical stage (p=0.031). The FADD from normal tissue was statistically different in relation to age (p=0.039), sex (p=0.055), clinical stage (p=0.019), and Fas was different in relation to tumor size (p=0.012). In the tumor, we observed a correlation between FasL and Fas, FasL and FADD, and FasL and cleaved caspase 3. In the adjacent normal tissue, a correlation was observed between FasL and Fas, FasL and FADD. There was no association of another marker with sex, age, clinical stage, and survival. Our results suggest that these proteins mediate the early extrinsic apoptotic pathway in gastric cancer and adjacent normal mucosa. FasL protein binds to Fas protein and subsequently binds to death receptor FADD signaling activation of the extrinsic apoptotic pathway. In this phase, there was inhibition of caspase 8 and, consequently, decreased apoptosis.

Canonical and noncanonical Wnt pathways: a comparison between endometrial cancer type I and atrophic endometrium in Brazil.

CONTEXT AND OBJECTIVE The Wnt pathway is involved in tumorigenesis of several tissues. For this reason, we proposed to evaluate Wnt gene expression in endometrial cancer type I. DESIGN AND SETTING Cross-sectional study on materials gathered from the tissue bank of the Department of Pathology, Universidade Federal de São Paulo. METHODS Endometrial specimens were obtained from surgeries performed between 1995 and 2005 at São Paulo Hospital, Universidade Federal de São Paulo. The material was divided into two groups according to tissue type: Group A, atrophic endometrium (n = 15); and Group B, endometrial adenocarcinoma (n = 45). We compared the immunohistochemical expression of Wnt1, Frizzled-1 (FZD1), Wnt5a, Frizzled-5 (FZD5) and beta-catenin between endometrial cancer type I and atrophic endometrium. RESULTS Regarding Wnt1, FZD1 and Wnt5a expression, no significant association was observed between the groups. A significant association was observed between the groups in relation to FZD5 expression (P = 0.001). The proportion of FZD5-positive samples was significantly higher in group A (80.0%) than in group B (31.1%). Regarding the survival curve for FZD5 in group B, we did not find any significant association between atrophic endometrium and endometrial adenocarcinoma. We also did not find any significant association regarding beta-catenin expression (P = 1.000). CONCLUSION FZD5 is downregulated in endometrial adenocarcinoma, in comparison with atrophic endometrium.

Perda de amostras em tissue microarray: comparação entre técnicas com uso de fita adesiva comercial, lâminas silanizadas pelo método tradicional ou por método modificado

INTRODUCTION/OBJECTIVE: The tissue microarray (TMA) technique allows the evaluation of multiple tissue samples in a single block. One of the problems of TMA is the ungluing of tissue sections, thus commercial adhesive tape has been used to reduce this loss. There are no reports comparing the use of the commercial adhesive tape with the use of the modified silane-coated technique. The objective of this study was to compare section loss in slides using commercial adhesive tape, silane-coated microslides with the conventional technique or with the modified technique. MATERIAL AND METHOD: The TMA was constructed with hepatic tissue blocks embedded in paraffin, using a fixed base device, placing 32 cylinders of 2 mm in diameter in duplicate and 2.2 mm apart from each other. Fifteen 4-µm sections were placed on conventional silane-coated microslides at 4% (Group 1), 15 on silane-coated microslides with a modified technique (6% of silane and minimum use of acetone) (Group 2), and 15 on slides using commercial adhesive tape, according to the manufacturers recommendations (Group 3). All microslides were processed by immunohistochemistry for cytokeratin 18, with antigen retrieval accomplished by incubation with citrate buffer pH 6.0 with microwave enhancement. Samples loss was quantified and expressed as: total (> 80%), almost complete (75% to 79%) or partial (50% to 74%). RESULTS: The loss of sections was similar in all three groups (4.9 vs. 3.1 vs. 8.1, respectively) (analysis of variance [ANOVA], p = 0.3654). One slide using commercial adhesive tape showed artifactual ungluing of all sections and another one showed loss of 20 samples on one side of the slide. None of the silane-coated microslides showed such artifact. CONCLUSIONS: Silane-coated microslides show adequate results, require less technical training and reduce the cost of TMA procedure, what justifies their use in research. Moreover, the use of the modified silane-coating technique, with the reduction of acetone volume, lowers the costs and reduces chemical residues.

HSP27 and HSP70 Expression in Esophageal Squamous Cell Carcinoma

Twenty-eight specimens of Esophael squamous cell carcinoma (ESCC) were obtained by surgery procedures. The tissues were fixed in formalin and embedded in paraffin. In each case, all available hematoxylin and eosin stained sections were examined and a representative block was selected. The ages of these patients ranged from 40 to 93 years, with a mean age of 60 years. Results. The histological grade of tumors was 4 well-differentiated, 19 moderately differentiated and 5 poorly differentiated. Expression of Hsp27 and Hsp70 in ESCC was demonstrated in 23 (82,14%) and 26 (92,86%) cases, respectively. Adjacent normal mucosa was positive in 11 (39,29%) samples and 9 (32,15%) samples for Hsp27 and Hsp70, respectively. No relationship between the expression of Hsp27 and Hsp70 with the clinicopathological parameters, including gender, age, surgical margin, lymph node status and tumor differentiation. The median follow-up period was 60 months. Survival analysis of patients with ESCC showed no relationship with the expression of Hsp27 and Hsp70. Conclusion. Taken together, our results demonstrate that Hsp27 and Hsp70 are expressed in ESCC tissues, but they are not good prognostic factor for patients with ESCC.

Expression of VEGF and Cox-2 in Patients with Esophageal Squamous Cell Carcinoma

Esophageal cancer is a highly aggressive neoplasm. In Brazil, it is the sixth most frequent among men and fifteenth among women. The most common type is squamous cell carcinoma (SCC), responsible for 96% of cases. Twenty-eight specimens of Esophael squamous cell carcinoma (ESCC) were obtained by surgery procedures.The tissues were fixed in formalin and embedded in paraffin. In each case, all available hematoxylin and eosin stained sections were examined and a representative block was selected. The ages of these patients ranged from 40 to 93 years, with a mean age of 60 years. Results: The histological grade of tumors was 4 well-differentiated, 19 moderately differentiated and 5 poorly differentiated. Expression of Cox-2 and VEGF in ESCC was demonstrated in 23 (82,14%) and 13 (44,43%) cases, respectively. Adjacent normal mucosa was positive in 11 (39,29%) samples and 9 (32,15%) samples for Cox-2 and VEGF, respectively. No relationship between the expression of Cox-2 and VEGF with the clinicopathological parameters, including gender, age, surgical margin, lymph node status and tumor differentiation. The median follow-up period was 60 months. Survival analysis of patients with ESCC showed no relationship with the expression of Cox-2 and VEGF. Conclusion: VEGF and Cox-2 are expressed in ESCC. Cox-2, VEGF, play a significant role in the origin and development of ESCC and the inhibitors of these proteins could prove to be an important therapeutic tool in the control of this disease.

The destruction complex of beta-catenin in colorectal carcinoma and colonic adenoma

ABSTRACT Objective To evaluate the destruction complex of beta-catenin by the expression of the proteins beta-catetenin, adenomatous polyposis coli, GSK3β, axin and ubiquitin in colorectal carcinoma and colonic adenoma. Methods Tissue samples from 64 patients with colorectal carcinoma and 53 patients with colonic adenoma were analyzed. Tissue microarray blocks and slides were prepared and subjected to immunohistochemistry with polyclonal antibodies in carcinoma, adjacent non-neoplastic mucosa, and adenoma tissues. The immunoreactivity was evaluated by the percentage of positive stained cells and by the intensity assessed through of the stained grade of proteins in the cytoplasm and nucleus of cells. In the statistical analysis, the Spearman correlation coefficient, Student’s t, χ2, Mann-Whitney, and McNemar tests, and univariate logistic regression analysis were used. Results In colorectal carcinoma, the expressions of beta-catenin and adenomatous polyposis coli proteins were significantly higher than in colonic adenomas (p<0.001 and p<0.0001, respectively). The immunoreactivity of GSK3β, axin 1 and ubiquitin proteins was significantly higher (p=0.03, p=0.039 and p=0.03, respectively) in colorectal carcinoma than in the colonic adenoma and adjacent non-neoplastic mucosa. The immunohistochemistry staining of these proteins did not show significant differences with the clinical and pathological characteristics of colorectal cancer and colonic adenoma. Conclusions These results suggest that, in adenomas, the lower expression of the beta-catenin, axin 1 and GSK3β proteins indicated that the destruction complex of beta-catenin was maintained, while in colorectal carcinoma, the increased expression of beta-catenin, GSK3β, axin 1, and ubiquitin proteins indicated that the destruction complex of beta-catenin was disrupted.