Nikolaos Nikiteas

Circulating MicroRNA in inflammatory bowel disease

BACKGROUND MicroRNAs (miRNAs) consist of a group of small noncoding RNAs that partially regulate gene expression. We investigated the expression patterns of commonly deregulated miRNAs in Crohns disease (CD) and ulcerative colitis (UC) in peripheral blood samples of inflammatory bowel disease patients. PATIENTS AND METHODS This study consisted of 128 CD and 88 UC patients, as well as 162 healthy controls. The expression patterns of the miRNA species were quantitatively assayed using reverse transcription and real-time RT-PCR. Stem-loop complementary DNAs (cDNAs) were synthesized using looped reverse transcription primers specific for each miRNA. RESULTS MiR-16, miR-23a, miR-29a, miR-106a, miR-107, miR-126, miR-191, miR-199a-5p, miR-200c, miR-362-3p and miR-532-3p were expressed at significantly higher levels in the blood from patients with CD compared with the healthy controls. No significant differences were observed when the CD patients were classified according to disease location and phenotype. In the UC cases three miRNAs (miR-16, miR-21, miR-28-5p, miR-151-5p, miR-155 and miR-199a-5p) were significantly increased compared to healthy controls. miR-155 was the most highly expressed of the UC-associated miRNA in blood samples. CONCLUSIONS Our results suggest that several miRNAs could distinguish CD from UC by real-time PCR. This further highlights the putative role of miRNAs as contributors to IBD pathogenesis. They may help develop new non-invasive biomarkers to distinguish UC and CD.

Vascular Complications in Renal Transplantation: A Single-Center Experience in 1367 Renal Transplantations and Review of the Literature

Renal transplantation is the treatment of choice for end-stage renal disease. Vascular complications in renal transplantation are not uncommon and may often lead to allograft loss. The most common vascular complications are transplant renal artery stenosis, transplant renal artery thrombosis, transplant renal vein thrombosis, biopsy-induced vascular injuries, pseudoaneurysm formation, and hematomas. Transplant renal artery and vein thrombosis have an early onset and a dramatic clinical manifestation and usually lead to allograft loss. In contrast, transplant renal artery stenosis has better treatment possibilities, whereas the rest do not occur so often. In our institution, 1367 renal transplantations were performed from September 1980 to April 2005. During this period, we encountered 38 major vascular complications leading to graft loss and 19 transplant renal artery stenoses with successful treatment in the majority of cases. According to these data, we can conclude that renal transplantation is a safe therapeutic procedure for renal failure.

COMMON POLYMORPHISMS IN THE VASCULAR ENDOTHELIAL GROWTH FACTOR GENE AND COLORECTAL CANCER DEVELOPMENT, PROGNOSIS, AND SURVIVAL

Angiogenesis plays an important role in growth, progression, and metastasis of tumors. The most important regulator of angiogenesis is vascular endothelial growth factor (VEGF). VEGF expression has been associated with advance stage and poor survival of several cancers. In the present study we evaluated the association of functional polymorphisms in the VEGF gene with colorectal cancer development, prognosis, and survival. Three hundred twelve consecutive patients with surgically treated colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from paraffin‐embedded tissue and five VEGF (−2578C>A, −1154G>A, −634G>C, −460T>C, and +936C>T) gene polymorphisms were determined using a polymerase chain reaction‐restriction fragment length polymorphism assay. VEGF −2578C>A, −1154G>A, −634G>C, −460T>C, and +936C>T genotype and allele frequencies were similar among patients and controls. There was a trend showing carriers of the −2578A and +936T alleles more frequent among patients with CRC, but these differences did not reach statistical significance. Furthermore, no correlation was found between all these variants and tumor characteristics like size, histological grading, positive regional lymph node metastases or tumor stage. However, the −2578AA, −634CC, and +936TT genotypes found to be related with a significantly lower overall survival in our study. In conclusion, VEGF gene polymorphisms were found to be an independent prognostic marker for Greek CRC patients.

TGF-beta signalling in colon carcinogenesis

Colorectal cancer remains the most common cancer and the second leading cause of cancer mortality in Europe. There are a number of pathways that have been implicated in colorectal carcinogenesis, including TGF-beta (TGF-β)/Smad signalling pathway. The TGF-β pathway is involved in several biological processes, including cell proliferation, differentiation, migration and apoptosis. Here we review the role of TGF-β signalling cascade in colorectal carcinogenesis and provide some new molecular insights that may aid efforts towards targeted antitumor therapies.

Survivin -31G/C promoter polymorphism and sporadic colorectal cancer

IntroductionSurvivin is an apoptotic inhibitor, plays an important role in cell cycle regulation, and may be involved in the development and progression of cancer. A common polymorphism at the survivin gene promoter (-31 G/C) has been shown to influence survivin expression and the risk for cancer.AimThe aim of the present study was to investigate whether this polymorphism could be involved in the sporadic colorectal cancer (CRC) development, prognosis, and survival.Materials and methodsThe -31G/C polymorphism of survivin promoter was analyzed by polymerase chain reaction (PCR) restriction fragment length polymorphism method in biopsies from 312 patients with sporadic CRC and 362 healthy individuals. Survivin messenger RNA (mRNA) expression in CRC tissues was detected by quantitative reverse transcriptase PCR.Results and discussionThe genotype frequencies for -31GG, -31GC, and -31CC were 21.79%, 41.99%, and 36.22% in CRC patients and 33.98%, 45.03%, and 20.99% in healthy subjects, respectively. The frequencies of the survivin -31C allele and CC genotype were significantly higher in CRC patients than in healthy subjects (p < 0.0001). Homozygotes for the -31CC survivin genotype, expressed 1.6-fold higher mRNA levels of survivin compared to cases with the -31GG and -31GC genotypes.ConclusionThe -31CC genotype of survivin promoter is associated with CRC and may be a risk factor for CRC.

Quantum dots hold promise for early cancer imaging and detection

Despite all major breakthroughs in recent years of research concerning the complex events that lead to cancer expression and metastasis, we are not yet able to effectively treat cancer that has spread to vital organs. The various clinical phases originating from cancer diagnosis through treatment and prognosis require a comprehensive understanding of these events, to utilise pre‐symptomatic, minimally invasive and targeted cancer management techniques. Current imaging modalities such as ultrasound, computed tomography, magnetic resonance imaging and gamma scintigraphy facilitate the pre‐operative study of tumours, but they have been rendered unable to visualise cancer in early stages, due to their intrinsic limitations. The semiconductor nanocrystal quantum dots (QDs) have excellent photo‐physical properties, and the QDs‐based probes have achieved encouraging developments in cellular (in vitro) and in vivo molecular imaging. However, the same unique physical and chemical properties which renowned QDs attractive may be associated with their potentially catastrophic effects on living cells and tissues. There are critical issues that need to be further examined to properly assess the risks associated with the manufacturing and use of QDs in cancer management. In this review, we aim to describe the current utilisation of QDs as well as their future prospective to decipher and confront cancer.

A New Approach to Accurate Diagnosis of Acute Appendicitis

This study aimed (1) to develop a simple scoring system incorporating ultrasound (US) examination and clinical or laboratory predictors for increasing diagnostic accuracy in acute appendicitis (AA), and (2) to evaluate the performance of the scoring system as compared to that of previous models. Fifteen variables including US assessment for patients admitted with suspected AA were considered in multivariate analysis using the finding of AA at operation as the end point (internal study). The new score, together with 11 previous ones, was applied to a prospective independent population of subjects with suspected AA, and the respective performances were compared (external validation study). Among 303 patients (170 males, mean age 28.3 ± 13.3 years) of the internal study, 161 went on to surgery, and 130 had AA at operation. Four independent correlates of AA were identified and used for the derivation of the following integer-based scoring system: number of points = 6 for US demonstrating AA + 4 for tenderness in the right lower quadrant + 3 for rebound tenderness + 2 for leukocyte count >12,000/μl. In the external study (201 subjects, 105 males, mean age 28.7 ± 11.9 years, 109 operated, 87 with AA), when the cut-off of ≥ 8 points for AA was used, sensitivity, specificity, accuracy, and area under the curve of the proposed score were 95.4%, 97.4%, 96.5%, and 93%, respectively, exceeding noticeably the previous models. The proposed scoring system introduces a quantitative combination of the clinical evaluation with US imaging and a marker of inflammatory response, which may enhance the diagnostic accuracy for subjects with suspected AA especially in geographical areas where CT scanning is not readily available on a 24-hour basis.

Morbid Obesity and Sleeve Gastrectomy: How Does It Work?

Laparoscopic sleeve gastrectomy is known to be a safe and effective procedure for treating morbid obesity and is performed with increasing frequency both in Europe and the USA. Despite its broad use, many questions about the remaining gastric tube diameter, its long-term efficacy, its effects on gastric emptying, and the hormones involved still remain to be answered. In order to use such a relatively new surgical procedure wisely, it is essential for every surgeon and physician to understand how sleeve gastrectomy acts in obesity and what its potential benefits on the patients’ metabolism are. This review focuses on the most important pathophysiologic questions referred to sleeve gastrectomy on the literature so far, in an attempt to evaluate the different issues still pending on the subject.

Vascular endothelial growth factor and endoglin (CD-105) in gastric cancer

BackgroundVascular endothelial growth factor (VEGF) overexpression has been associated with advanced stage and poor survival in several cancers. Additionally, CD-105 (endoglin) was proposed as a marker of neovascularization in solid malignancies. The aim of the present study was to (1) evaluate the VEGF and CD-105 expression in gastric carcinoma, (2) determine the role of VEGF gene sequence variations in VEGF expression in gastric carcinoma, and (3) correlate the results of VEGF and CD-105 expression with other standard prognostic parameters, such as size, grade, stage of the disease, metastases, and patient survival.MethodsVEGF and CD-105 expression were evaluated in 100 unrelated gastric cancer patients using immunohistochemistry. For the genotyping, DNA was isolated from the blood of the gastric cancer patients and from 100 healthy individuals. The genotyping was performed by polymerase chain–restriction fragment length polymorphism analysis.ResultsVEGF protein was strongly expressed in the cytoplasm of 36% of the gastric carcinoma samples tested. In all cases, high VEGF expression was accompanied with high endoglin expression. Our results revealed no statistical significant association of any VEGF gene polymorphism with the VEGF and endoglin expression. The correlation of VEGF/CD-105 expression with the clinicopathological parameters of gastric cancer showed that the high expression of VEGF/CD015 was correlated only with lymph node metastasis (P = 0.028). The Kaplan-Meier survival curves have shown a clear association of overall survival after diagnosis of gastric cancer with high VEGF, as well as high CD-105 expression.ConclusionOur results support that VEGF and CD-105 are closely relevant to lymph node metastasis and act as two valuable indicators of prognosis.

OCT4 spliced variant OCT4B1 is expressed in human colorectal cancer

OCT4, a POU‐domain transcription factor is considered to be a key factor in maintaining the pluripotency of stem cells. Several OCT4 isoforms are differentially expressed in human pluripotent and non‐pluripotent cells. Reactivation of OCT4 expression is postulated to occur in differentiated cells that have undergone tumorigenesis. To examine OCT4 expression in colorectal cancer (CRC) tissues, and to assess the efficacy of OCT4 as a potential biomarker for CRC, in this study, we investigated its expression in CRC tissues, evaluated its relationship to various clinicopathological parameters and defined the isoform of OCT4 that was found to be expressed in CRC cases. Primary tumor tissues and matching adjacent non‐cancerous tissues were obtained from 84 CRC patients. OCT4 expression and isoform determination were documented by reverse transcription‐PCR and real‐time PCR. OCT4, Sox‐2, and NANOG localization were performed using immunohistochemistry. The isoforms expressed in the studied cases were confirmed by sequencing. Twenty biopsy specimens representing healthy tissues, retrieved from colonoscopy were studied in parallel as controls. OCT4 expression levels were higher in CRC tissues compared to matching, adjacent non‐cancerous tissues, and healthy controls. Additionally, the levels of OCT4 expression in CRC tissues correlated with tumor stage. OCT4 and Sox‐2 were localized in the nuclei and the cytoplasm of CRC cells. In all CRC cases, we found that the OCT4B1 isoform is expressed. Over‐expression of OCT4B1 was found in poorly and moderately differentiated CRC tissues. In conclusion, the data imply that OCT4B1 isoform may represent a potential biomarker for the initiation, progression, and differentiation of CRC. Mol. Carcinog.