Lymphatic vessel endothelial hyaluronan receptor 1 immunocytochemical staining for pancreatic islets and pancreatic endocrine tumors

Podoplanin and PROX1 Expression in Hypercaloric Diet-induced Pancreatic Injuries

BACKGROUND

The role of podoplanin (PDPN) and homebox prospero gene 1 (PROX1) in early stages of pancreatic islet changes induced by hypercaloric diet is unclear. The aim of this study was to study PDPN and PROX1 variability in pancreatic islets after a hypercaloric diet in a rat experimental model.

MATERIALS AND METHODS

Pancreatic biopsies harvested from Sprague-Dawley rats at 3, 6, and 9 weeks following hypercaloric diet intake were evaluated for morphological and molecular changes of Langerhans islets based on PDPN and PROX1 expression Results: Six weeks of hypercaloric diet induced hypertrophy of pancreatic islets with focal expression of Pdpn and Prox1 mRNA. At 9 weeks of hypercaloric diet, strong peri-insular inflammation was found around hypertrophic islets highly expressing PDPN, and lacking Prox1 mRNA and protein expression.

CONCLUSION

This is the first report of Pdpn and Prox1 mRNA expression variability and involvement in early steps of pancreatic islet changes following hypercaloric food intake.

Clinical significance of CCBE1 expression in lung cancer

Lymph node metastasis (LNM) is one of the major causes of cancer-associated morbidity and mortality in patients with lung cancer following radical pulmonary carcinoma resection. The present study aimed to investigate the relationship between the expression of collagen and calcium-binding epidermal growth factor domain-containing protein 1 (CCBE1) and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1) in tumor tissue with the clinical prognosis of lung cancer. The present study included 40 patients with lung cancer that underwent pulmonary carcinoma resection, including 10 patients with LNM, and 10 control patients who underwent pulmonary bullae resection. CCBE1 and LYVE1 expression was assessed in samples from normal and tumor tissue using polymerase chain reaction, western blot analysis and immunohistochemistry. CCBE1 expression appeared to be decreased in lung tumor tissue and further downregulated in samples from patients with LNM, and was revealed to be correlated with poor clinical outcome. Conversely, LYVE1 expression appeared to be upregulated in lung cancer tissue. In conclusion, the present results suggested that CCBE1 and LYVE1 may have potential as biomarkers for the identification of lung cancer patients at a high risk of LNM.

PGP 9.5 immunocytochemical staining for pancreatic endocrine tumors

AIMS/HYPOTHESIS

Protein gene product 9.5 (PGP 9.5) is a marker for neuroendocrine cells but has not been used for pancreatic islet cells and pancreatic endocrine tumors (PETs). Antibodies for PGP 9.5 are now commercially available for immunocytochemical study, with which immunostaining may be able to differentiate between benign and malignant PETs.

RESULTS

All 4 kinds of normal islet cells were positively immunostained for PGP 9.5-moderately positive for β-cells and strongly positive for δ-cells, whereas ganglion cells were immunostained more strongly than islet cells. Nine of 12 insulinomas were moderately to strongly positive for PGP 9.5. Two glucagonomas, 3 of 6 pancreatic polypeptidomas (PPomas), 3 of 9 gastrinomas, and 2 of 4 non-functioning PETs were negative for PGP 9.5.

MATERIALS AND METHODS

Thirty-four PETs were immunocytochemically stained for PGP 9.5 using a rabbit polyclonal antibody together with immunostaining for 4 pancreatic hormones, chromogranin A (CgA), and gastrin. PETs consisted of 12 insulinomas, 2 glucagonomas, 1 somatostatinoma (SRIFoma), 6 PPomas, 9 gastrinomas, and 4 non-functioning PETs.

CONCLUSION/INTERPRETATION

PGP 9.5 immunostaining was universally positive for 4 kinds of islet cells and was moderately to strongly positive for 9 of 12 (75%) insulinomas. All 22 non-β-cell PETs were negative or weakly positive for PGP 9.5, and thus negative or weakly positive PGP 9.5 immunostaining may be used as a marker for potential malignancy and poor prognosis for non-β-cell PETs.

Immunohistochemical endothelial markers: a review

A relatively large number of new endothelial markers that can assist in the diagnosis and classification of endothelial and vascular neoplasms have become available over the past few years. The expression of these markers, however, differs considerably among the various tumors. A selection of markers that have potential diagnostic utility or are of current interest among pathologists are reviewed and compared with some of the more traditional markers that have been employed in diagnostic pathology.

Long-term plasma ghrelin and leptin modulation after sleeve gastrectomy in Wistar rats in comparison with gastric tissue ghrelin expression

BACKGROUND

Sleeve gastrectomy (SG) is a gaining ground operation amongst the ones applied for treatment of morbid obesity. Though SG is a food limiting operation, the removal of the gastric fundus where ghrelin is mainly produced may indicate a hormonal impact of the procedure. The purpose of this experiment is to study how SG affects the levels of ghrelin and leptin.

METHODS

Twenty-four male, adult, diet induced obese Wistar rats were divided randomly into groups, one submitted to SG and the other to a sham operation. Fasting blood samples were taken before the operation and 14 weeks after the operation (leptin and acylated and des-acyl ghrelin levels were measured). Tissue samples from the gastric fundus were taken during the operation and at the end of the experiment, and ghrelin expression was measured with RT-PCR.

RESULTS

Statistically significant weight loss was achieved comparing the weight progress of the SG group and the sham operation group. Serum leptin levels were significantly reduced in the SG group (p < 0.05) but not in the sham operation group. Serum acylated ghrelin was not significantly affected in both groups, but a significant decrease was documented in serum des-acyl ghrelin in the SG group (p < 0.05). RT-PCR analysis of the gastric fundus documented a significant decrease (p < 0.0001) in the expression of ghrelin in the SG group.

CONCLUSIONS

SG may lead in significant long-term weight loss. SG affects the serum levels of leptin and des-acyl ghrelin but not the levels of acylated ghrelin in this animal model.

Small intestinal neuroendocrine cell pathobiology: 'carcinoid' tumors

PURPOSE OF REVIEW

Neuroendocrine tumors, particularly small intestinal tumors, also grouped as 'carcinoids', are defined by an increasing incidence and prevalence, a poor response to current therapies, and confusion regarding appropriate models for drug development. Despite these issues, approximately 350 studies were published in the last year.

RECENT FINDINGS

Two sources of confusion are clearly apparent. First, pharmacotherapeutic studies using pancreatic tumor cell lines as models for small intestinal or 'carcinoid' tumor biology are considered appropriate. Second, there is continued inclusion and analysis of pancreatic endocrine tumors with small intestinal neuroendocrine tumors in clinical studies. One highlight of this year is additional data confirming the significant differences between pancreatic tumor cell lines and small intestinal cell lines, the different gene expressions, for example, PAX8, between these two tumor types, and the observations that these two tumors respond differently in clinical trials, for example, to mammalian target of rapamycin (mTOR) inhibitors. Other highlights include delineating the role of the tumor microenvironment in the development of fibrosis and developing a minimum pathology dataset and a prognostic nomogram that may have utility in stratifying patients for clinical studies.

SUMMARY

A number of interesting studies have been published during 2009-2010, but critical areas remain that require resolution. Current data, for the most part, reflect amplification of previously held concepts with modest advances in novel information.

Immunocytochemical localization of lymphatic and venous vessels in colonic polyps and adenomas

Histopathological localization of lymphatic vessels has been hindered because of a lack of suitable immunocytochemical markers for lymphatic vessels. Using lymphatic vessels endothelial hyaluronan receptor-1 (LYVE-1) immunocytochemical staining, hyperplastic polyps, tubular adenomas to villous adenomas, were investigated for lymphatic vessels compared with immunostained blood vessels using factor-8. Four cases each of hyperplastic polyps, tubular adenomas to villous adenomas, were routinely fixed in formalin and embedded in paraffin and were immunostained using goat anti-LYVE-1 for lymphatic vessels and rabbit anti-factor-8 for blood vessels. In normal colon and hyperplastic polyps, slender lymphatic vessels were noted in muscularis mucosa, which spread into the base of colonic crypt, whereas round venous vessels, they extend into lamina propria. In tubular adenomas, small lymphatic and venous vessels were noted in broad fibrous stalks. In villous adenomas, smaller lymphatic and venous vessels were noted in fine intervillous stroma. In normal colon and hyperplastic polyps, slender, irregularly shaped lymphatic vessels were present in muscularis mucosa, spreading into the base of the colonic crypt. In tubular adenomas, small lymphatic and venous vessels were noted in fibrous stalks. In villous adenomas, smaller lymphatic and venous vessels were noted in intervillous stroma. There are no increased lymphatic and venous vessels in intermucosal stroma and stalks of adenomas compared with normal colon.