Maria Lambropoulou

Human leptin induces angiogenesis in vivo

Leptin is an adipocyte-produced peptide, which plays a crucial role in the regulation of body weight. There is also evidence that leptin stimulates endothelial cell proliferation and the formation of capillary-like tubes in vitro. The disc angiogenesis system was used to measure the angiogenic effect of leptin in vivo. Discs containing 25, 50, 100 and 250ng/ml of leptin were implanted subcutaneously in Wistar rats, removed after a growth period of 7 and 14 days, and compared with spontaneous growth controls and with positive controls containing equivalent doses of vascular endothelial growth factor (VEGF). Discs were examined morphologically for stroma and vessel development and by immunohistochemistry for quantitative evaluation of angiogenesis. The specificity of the angiogenic effect of leptin was tested by blocking leptin with a polyclonal anti-leptin antibody. Leptin induced a significant level of angiogenesis in a dose-dependent manner both at 7 and 14 days, with a peak at the dose of 100ng/ml. The angiogenic activity of leptin was completely abolished by the anti-leptin neutralizing antibody. VEGF also induced significant dose-dependent angiogenesis at the same time points with a peak observed at a concentration of 100ng/ml. The angiogenic response to leptin was significantly higher at 7 days compared with VEGF but not at the 14-day time point. In conclusion, leptin has a specific angiogenic effect in vivo, which is dose- and time-dependent in a concentration range of 25-250ng/ml. This effect is equivalent to the angiogenic effect of VEGF but is evident earlier compared with VEGF.

Corticotropin-releasing factor (CRF) receptor type 2 in the human stomach: Protective biological role by inhibition of apoptosis

Corticotropin‐releasing factor agonists exert inhibitory effects in stomach functions possibly through peripheral routes. We have previously reported the expression of Urocortin (Ucn) I, an endogenous ligand of both CRF receptor types CRF1 and CRF2, in the human stomach. We examined CRF1 and CRF2 expression in the same tissue. Using RT‐PCR, CRF2 but not CRF1 transcripts were detected in RNA extracts from normal human stomach. In addition, immunohistochemical analysis revealed receptor protein in epithelial gastric cells. In order to investigate the biological role of CRF2 in these cells, an in vitro model was established, using the gastric cancer cell line AGS transiently transfected to express functional CRF2. The effect of the CRF2 endogenous ligands CRF, Ucns I and II on the growth parameters of the AGS/CRF2 was examined. After 1 day of exposure, all three ligands reduced the degree of apoptosis (16%–19%, n = 9, P < 0.05) compared to non‐treated controls and this effect was observed for 3 days of treatment. No such effect was detected in non‐transfected cells, suggesting mediation through CRF2 receptors. Administration of CRF, Ucns I and II had no effect on the proliferation rate of AGS/CRF2 cells or on the release of PGE2 by them. Our results demonstrate CRF2 expression in the human gastric mucosa and indicate a physiological role of this receptor type in regulating apoptosis, an important parameter of gastric cell regeneration. Paracrine effects exerted by locally expressed endogenous ligands, such as Ucn I, support a significant role of the peripheral CRF system in gastric physiology. J. Cell. Physiol. 209: 905–911, 2006.

Organ Toxicity and Mortality in Propofol-Sedated Rabbits Under Prolonged Mechanical Ventilation

BACKGROUND: Prolonged administration of propofol at large doses has been implicated in propofol infusion syndrome in intensive care unit patients. In this study we investigated organ toxicity and mortality of propofol sedation at large doses in prolonged mechanically ventilated rabbits and determined the role of propofols lipid vehicle. METHODS: Eighteen healthy male rabbits were endotracheally intubated and sedated with propofol 2% (Group P), sevoflurane (Group S) or sevoflurane while receiving Intralipid 10% (Group SI). Sedation lasted 48 h or until death (Group P) or the maximum surviving period of Group P (Groups S and SI). The initial propofol infusion rate (20 mg · kg−1 · h−1) or sevoflurane concentration (1.5%) was adjusted, if needed, to maintain a standard level of sedation. Blood biochemical analysis was performed in serial blood samples and histologic examination in the heart, lungs, liver, gallbladder, kidneys, urinary bladder, and quadriceps femoris muscle at autopsy. RESULTS: The mortality rate was 100% (surviving period, 26–38 h) for Group P, whereas 0% for Groups S and SI. The initial propofol infusion rate had to be increased up to 65.7 ± 4.6 mg · kg−1 · h−1 and sevoflurane concentration up to 4%. Serum liver function indices, lipids and creatine kinase were significantly increased (P < 0.05) in Groups P and SI and lactate was increased only in Group P, whereas amylase was increased in all groups. In Group P, histologic examination revealed myocarditis, pulmonary edema with interstitial pneumonia, hepatitis, steatosis, and focal liver necrosis, cholangitis, gallbladder necrosis, acute tubular necrosis of the kidneys, focal loss of the urinary bladder epithelium, and rhabdomyolysis of skeletal muscles; in Group S, low-grade bronchitis and incipient inflammation of the liver and the kidneys; and in Group SI, low-grade bronchitis, liver steatosis and hepatitis, and incipient inflammation of the gallbladder, kidneys, and urinary bladder. CONCLUSIONS: Continuous infusion of 2% propofol at large doses for the sedation of rabbits undergoing prolonged mechanical ventilation induced fatal multiorgan dysfunction syndrome similar to the propofol infusion syndrome seen in humans. Our novel findings including lung, liver, gallbladder, and urinary bladder injury were also noted. The role of propofols lipid vehicle in the manifestation of the syndrome was minor. Sevoflurane proved to be a safe alternative medication for prolonged sedation.

Assessment of SOX17 DNA methylation in cell free DNA from patients with operable gastric cancer. Association with prognostic variables and survival.

Abstract Background: DNA methylation represents one of the most common epigenetic changes in human cancer providing important information regarding carcinogenesis. A possible role as a prognostic indicator has also been proposed. The aim of our study was to evaluate the prognostic significance of SOX17 promoter methylation status in patients with operable gastric cancer. Methods: Using methylation-specific PCR (MSP) we examined the incidence and prognostic significance of SOX17 methylation status in cell free circulating DNA in the serum of 73 patients with operable gastric cancer. Fifty-one patients were male (69.9%), their median age was 65 years, 43 patients (58.9%) had regional lymph node involvement and all had a Performance Status (WHO) of 0–1. Results: SOX17 promoter was found to be methylated in 43 out of 73 gastric cancer serum samples examined (58.9%). All 20 control serum samples from healthy individuals were negative. Overall survival (OS) was found to be significantly associated with SOX17 methylation (p=0.049). A significant correlation between methylation status and differentiation (p=0.031) was also observed. No other significant associations between different tumor parameters examined and SOX17 methylation status were observed. Conclusions: SOX17 promoter methylation in cell free DNA of patients with operable gastric cancer is a frequent event and may provide important information regarding prognosis in this group of patients.

Human embryonal epithelial cells of the developing small intestinal crypts can express the Hodgkin-cell associated antigen Ki-1 (CD30) in spontaneous abortions during the first trimester of gestation

BackgroundKi-1 (CD30) antigen expression is not found on peripheral blood cells but its expression can be induced in vitro on T and B lymphocytes by viruses and lectins. Expression of CD30 in normal tissues is very limited, being restricted mainly to a subpopulation of large lymphoid cells; in particular, cells of the recently described anaplastic large cell lymphoma (ALCL), the Reed-Sternberg (RS) cells of Hodgkins lymphoma and scattered large parafollicular cells in normal lymphoid tissues. More recent reports have described CD30 expression in non-hematopoietic and malignant cells such as cultured human macrophages, human decidual cells, histiocytic neoplastic cells, mesothelioma cells, embryonal carcinoma and seminoma cells.ResultsWe investigated the immunohistochemical expression of CD30 antigen in 15 paraffin-embedded tissue samples representing small intestines from fetuses after spontaneous abortion in the 8th, 10th and 12th weeks using the monoclonal antibody Ki-1. Hormones had been administered to all our pregnant women to support gestation. In addition, a panel of monoclonal antibodies was used to identify leukocytes (CD45/LCA), B-lymphocytes (CD20/L-26) and T-lymphocytes (CD3). Our findings were correlated with those obtained simultaneously from intestinal tissue samples obtained from 15 fetuses after therapeutic or voluntary abortions.ConclusionsThe results showed that: (1) epithelial cells in the developing intestinal crypts express the CD30 (Ki-1) antigen; (2) CD30 expression in these epithelial cells is higher in cases of hormonal administration than in normal gestation. In the former cases (hormonal support of gestation) a mild mononuclear intraepithelial infiltrate composed of CD3 (T-marker)-positive cells accompanies the CD30-positive cells.

Co-expression of survivin, c-erbB2, and cyclooxygenase-2 (COX-2): prognostic value and survival of endometrial cancer patients

AimThe purpose of this study was to investigate the co-expression of survivin, c-erbB2, and COX-2 in endometrial cancer tissues and evaluate its prognostic significance in endometrial cancerMethodsTumor tissue biopsies from 110 patients with primary untreated endometrial carcinomas were studied by immunohistochemistry. Statistical analysis evaluated correlation of antigen expression with tumor stage, grade, myometrial invasion, and histologic type. Association with disease outcome was also investigatedResultsThe results showed that expression of the three antigens was independently associated with histological grade, disease stage, and myometrial invasion. Clinicopathological parameters were also associated with the number of antigens expressed by each tumor, the expression of more antigens correlating with advanced stage disease and deep myometrial invasion. In a 10-year follow-up, patients with tumors expressing more of these three antigens had significantly lower survival rate that those with smaller expression scoreConclusionsOur results indicate that the co-expression score has independent prognostic value for endometrial cancer.

An unusual case of posttransplant peritoneal primary effusion lymphoma with T-cell phenotype in a HIV-negative female, not associated with HHV-8

Primary effusion lymphoma (PEL) is a recently individualized form of non-Hodgkin’s lymphoma (WHO classification) that mainly develops in HIV infected males, more frequently in homosexuals and advanced stages of the disease (total CD4+ lymphocyte count below 100–200/μL). Occasionally, it appears in other immunodepressive states (such as solid organs transplant period) and even, although very rarely, in immunocompetent patients. From a pathogenetic point of view, PEL has been related to Kaposi’s sarcoma associated herpes virus (also named human herpesvirus 8, HHV-8), an etiological factor of Kaposi’s sarcoma. The relative infrequency of this disease, the absence of wide casuistics allowing a better characterization, and its unfavorable outcome support the need of a deeper knowledge. We present here the clinical-biological findings of a patient, HIV -seronegative, who was diagnosed with peritoneal PEL of T-cell origin, and not HHV-8-associated, five years after renal transplantation.

Prophylaxis with mesna prevents oxidative stress induced by ischemia reperfusion in the intestine via inhibition of nuclear factor‐κB activation

Background and Aim:  Mesna (2‐mercaptoethane‐sulfonate) has been shown to attenuate oxidative injury induced by ischemia reperfusion (I/R) in the kidneys, the liver, and the intestine; however, its mechanism of action has not been fully elucidated. We sought to determine a prophylactic admininstration schedule of mesna that would confer optimal antioxidant protection on the intestinal mucosa following I/R and to investigate whether mesnas action is mediated via inhibition of nuclear factor‐κB (NF‐κB) activity.

ERYTHROPOIETIN ENHANCES ANGIOGENESIS IN AN EXPERIMENTAL CYCLOSPORINE A‐INDUCED NEPHROTOXICITY MODEL IN THE RAT

1 Erythropoietin (EPO) is a hormone regulating the proliferation and differentiation of erythroid precursor cells. The hypothesis that haematopoietic and endothelial cells share a common haemanglioblast progenitor among others is based on the finding that both cell lineages express cell surface antigens, such as CD31 and CD34. 2 In the present study, we investigated the angiogenic potential of recombinant human erythropoietin on cyclosporine A (CsA)‐induced nephrotoxicity in the rat kidney and compared it with the effect of basic fibroblast growth factor (bFGF), a well‐known angiogenic factor. 3 Rats were divided into five groups: A (control), B (EPO treated), C (CsA treated), D (CsA + EPO treated) and E (CsA + bFGF treated). Mouse anti‐human CD31 and CD34 antibodies were used to evaluate the kidney vessels present in histological preparations. 4 Glomerular and peritubular capillaries in Group B (EPO) were increased compared with the control (Group A; P < 0.05). Reduction of the same kidney vessels (glomerular and peritubular capillaries) in Group C (CsA; P < 0.05) compared with controls was observed, whereas in Groups D (CsA + EPO treated) and E (CsA + bFGF treated), capillaries were increased compared with Group C (CsA; P < 0.05). 5 Erythropoietin has a significant angiogenic effect in rat kidney with CsA‐induced nephrotoxicity, similar to the effect of the other angiogenic factor bFGF.

Primary gastric Hodgkin's lymphoma: A case report and review of the literature

Primary gastric Hodgkins lymphoma is a rarely encountered lesion. Most cases are observed in the course of systemic disease. Other cases have been reclassified in retrospective studies as non-Hodgkins lymphomas, after the employment of immunohistochemistry. Some Hodgkins lymphomas may masquerade non-Hodgkins lymphomas, and vice versa. Therefore, an accurate diagnosis is important, as treatment and outcome differ significantly for these entities. We report a case of primary Hodgkins lymphoma arising in the stomach of a 46-year-old male, and discuss the diagnostic approach as well as the differentials of Hodgkins disease in this anatomic site.