Pathology

The Pathogenesis of Pheochromocytomas: Of Mice and Men (Doctoral Thesis)

Korpershoek, E. — 2011-11-11T00:00:00Z

Pheochromocytomas are neuro‐endocrine tumors that arise from the neural crest derived adrenal medullary chromaffin cells, and produce catecholamines. The first description of a patient with pheochromocytomas was done by Fränkel in 1886, but the term pheochromocytoma was invented by the pathologists Ludwig Pick in 1912, after the Greek words phaios, meaning dark or dusky, and chroma, meaning color, which refers to the dark discoloration of the tumor cells in the chromium‐salt reaction. During embryonic development, cells of the neural crest migrate along preprogrammed pathways, and differentiate into a variety of cell types, such as the intraadrenal and extra‐adrenal chromaffin cells, and the autonomic ganglion cells. The adrenal medulla is composed of chromaffin cells, which are arranged in clusters, enclosed by sustentacular cells and a stromal network. Apart from these structures, the medulla is highly vascularized, and this is also seen in pheochromocytomas. In general, chromaffin cells are thought to store either adrenalin or noradrenalin, but cells containing both catecholamines have been reported in mice. Pheochromocytomas can produce dopamine, adrenalin, noradrenalin, or a combination, depending on their genetic background. Catecholamine production results in sustained, labile or paroxysmal hypertension, and if patients are not treated appropriately, pheochromocytomas will almost always cause fatal cardiovascular events or other devastating complications. Pheochromocytomas occur in approximately 1 or 2 per 100,000 adults in the USA per year (0.001‐0.002%), but the exact incidence is not precisely known. The true incidence of pheochromocytomas is probably higher (towards 0.05%) as one in twenty cases of the incidentally‐found adrenal masses during autopsy, magnetic resonance imaging (MRI), computed tomography (CT), or abdominal ultrasonography, is a pheochromocytoma.

Comparison of non-invasive assessment to diagnose liver fibrosis in chronic hepatitis B and C patients (Article)

Stibbe, K.J.M. — 2011-07-01T00:00:00Z

Objective. Chronic viral hepatitis B and C cause liver fibrosis, leading to cirrhosis. Fibrosis assessment is essential to establish prognosis and treatment indication. We compared seven non-invasive tests, separately and in combination, in chronic hepatitis patients to detect early stages of fibrosis according to the Metavir score in liver biopsy. Material and methods. Galactose and methacetin breath tests (GBT and MBT), biomarkers (hyaluronic acid (HA), aspartate aminotransferase platelet ratio index (APRI), FibroTest, and Fib-4) and transient elastography (TE) were evaluated in 89 patients. Additionally, 31 healthy controls were included for evaluation of breath tests and biomarkers. Results. Serum markers (HA, APRI, FibroTest, and Fib-4) and elastography significantly distinguished non-cirrhotic (F0123) from cirrhotic (F4) patients (p < 0.001, p = 0.015, p < 0.001, p = 0.005, p = 0.006, respectively). GBT, HA, APRI, FibroTest, Fib-4, and TE detected F01 from F234 (p = 0.04, p = 0.011, p = 0.009, p < 0.001, p < 0.001, and p < 0.001, respectively). A combination of different tests (TE, HA, and FibroTest) improved the performance statistically, area under the curve (AUC) = 0.87 for F234, 0.92 for F34, and 0.90 for F4. Conclusion. HA, APRI, FibroTest, Fib-4, and TE reliably distinguish non-cirrhotic and cirrhotic patients. Except for MBT, all tests discriminate between mild and moderate fibrosis. As single tests: FibroTest, Fib-4, and TE were the most accurate for detecting early fibrosis; combining different non-invasive tests increased the accuracy for detection of liver fibrosis to such an extent and thus might be acceptable to replace liver biopsy.

Predictors for neoplastic progression in patients with Barrett's esophagus: A prospective cohort study (Article)

Sikkema, M. — 2011-07-01T00:00:00Z

Objectives: Patients with Barrett's esophagus (BE) have an increased risk of developing esophageal adenocarcinoma (EAC). As the absolute risk remains low, there is a need for predictors of neoplastic progression to tailor more individualized surveillance programs. The aim of this study was to identify such predictors of progression to high-grade dysplasia (HGD) and EAC in patients with BE after 4 years of surveillance and to develop a prediction model based on these factors. Methods: We included 713 patients with BE (2 cm) with no dysplasia (ND) or low-grade dysplasia (LGD) in a multicenter, prospective cohort study. Data on age, gender, body mass index (BMI), reflux symptoms, tobacco and alcohol use, medication use, upper gastrointestinal (GI) endoscopy findings, and histology were prospectively collected. As part of this study, patients with ND underwent surveillance every 2 years, whereas those with LGD were followed on a yearly basis. Log linear regression analysis was performed to identify risk factors associated with the development of HGD or EAC during surveillance. Results: After 4 years of follow-up, 26/713 (3.4%) patients developed HGD or EAC, with the remaining 687 patients remaining stable with ND or LGD. Multivariable analysis showed that a known duration of BE of 10 years (risk ratio (RR) 3.2; 95% confidence interval (CI) 1.3-7.8), length of BE (RR 1.11 per cm increase in length; 95% CI 1.01-1.2), esophagitis (RR 3.5; 95% CI 1.3-9.5), and LGD (RR 9.7; 95% CI 4.4-21.5) were significant predictors of progression to HGD or EAC. In a prediction model, we found that the annual risk of developing HGD or EAC in BE varied between 0.3% and up to 40%. Patients with ND and no other risk factors had the lowest risk of developing HGD or EAC (1%), whereas those with LGD and at least one other risk factor had the highest risk of neoplastic progression (18-40%). Conclusions: In patients with BE, the risk of developing HGD or EAC is predominantly determined by the presence of LGD, a known duration of BE of 10 years, longer length of BE, and presence of esophagitis. One or combinations of these risk factors are able to identify patients with a low or high risk of neoplastic progression and could therefore be used to individualize surveillance intervals in BE.

Characterization of BCAR4, a novel oncogene causing endocrine resistance in human breast cancer cells (Article)

Ernesto Godinho, M.F. — 2011-07-01T00:00:00Z

Resistance to the antiestrogen tamoxifen remains a major problem in the management of estrogen receptor-positive breast cancer. Knowledge on the resistance mechanisms is needed to develop more effective therapies. Breast cancer antiestrogen resistance 4 (BCAR4) was identified in a functional screen for genes involved in tamoxifen resistance. BCAR4 is expressed in 27% of primary breast tumors. In patients treated with tamoxifen for metastized disease high BCAR4 mRNA levels are associated with reduced clinical benefit and progression-free survival. Regarding tumor aggressiveness high BCAR4 mRNA levels are associated with a shorter metastasis free survival and overall survival. In the present study, we investigated the role of BCAR4 in endocrine resistance. Forced expression of BCAR4 in human ZR-75-1 and MCF7 breast cancer cells resulted in cell proliferation in the absence of estrogen and in the presence of various antiestrogens. Inhibition of estrogen receptor 1 (ESR1) expression with small interfering RNA (siRNA), implied that the BCAR4-induced mechanism of resistance is independent of ESR1. Highly conserved BCAR4 homologues of rhesus monkey, green monkey, and the less conserved common marmoset gene induced tamoxifen-resistant cell proliferation, in contrast to the distant BCAR4 homologues of bovine and rabbit. Injection of BCAR4-expressing ZR-75-1 cells into nude mice resulted in rapidly growing tumors. In silico analysis showed that BCAR4 mRNA is highly expressed in human placenta and oocyte, and absent in other normal tissues. In conclusion, BCAR4 is a strong transforming gene causing estrogen-independent growth and antiestrogen resistance, and induces tumor formation in vivo. Due to its restricted expression, BCAR4 may be a good target for treating antiestrogen-resistant breast cancer.

Alpha-internexin expression predicts outcome in anaplastic oligodendroglial tumors and may positively impact the efficacy of chemotherapy (Article)

Mokhtari, K. — 2011-07-01T00:00:00Z

BACKGROUND: Although it has been demonstrated that the neuronal intermediate filament alpha-internexin (INA) is closely related to 1p19q codeletion in gliomas, its prognostic and predictive value has not yet been confirmed in a prospective trial. The authors of this report assessed the prognostic significance of INA expression and its correlation with relevant clinical and molecular characteristics in the prospective, randomized European Organization for Research and Treatment of Cancer (EORTC) 26951 trial of adjuvant procarbazine, lomustine, and vincristine (PCV) in patients with anaplastic oligodendroglial tumors (AOTs). METHODS: INA immunohistochemistry expression in tumors from 92 patients who were included in the EORTC 26951 trial was analyzed independently by 2 observers and was correlated with relevant clinical characteristics, including progression-free survival (PFS) and overall survival (OS), and with molecular features, including 1p/19q codeletion, isocitrate dehydrogenase 1 and 2 gene (IDH1/IDH2) mutation, and O-6 methylguanine-DNA methyltransferase (MGMT) promoter methylation status. RESULTS: INA expression was observed in 33 tumors and was strongly correlated with 1p/19q codeletion, IDH1 mutations, and MGMT promoter methylation. It was associated with significantly better PFS and OS independent of the treatment received. By using Cox proportional hazard modeling for OS with stepwise selection, INA expression, patient age, and performance status were identified as independent prognostic factors. The results indicated that INA expression may have an impact on the efficacy of combined radiotherapy plus PCV. CONCLUSIONS: In a homogeneously treated group of patients with grade III AOTs, INA expression had strong favorable prognostic significance for OS and may have predictive value for sensitivity to chemotherapy. Copyright

Immunohistochemical ETS-related gene detection in a Japanese prostate cancer cohort: Diagnostic use in Japanese prostate cancer patients (Article)

Furusato, B. — 2011-07-01T00:00:00Z

Chromosomal rearrangements that result in high expression levels of the ETS-related gene (ERG) present in approximately 50% of prostate cancer (PCa) patients, making this one of the most common oncogenic alterations in PCa. However, ERG overexpression at the protein level has not been rigorously evaluated in Japanese PCa patients. In this study, we evaluated ERG expression using antibody-based detection in 230 prostate specimens in a Japanese PCa cohort. Overall, we identified 20.1% ERG-positive PCa cases. ERG was not detected in benign glands. The specificity of ERG staining for detecting PCa was almost 100%; all of the ERG-positive samples were also diagnosed as PCa. The expression level of the ERG protein correlated with clinicopathological variables, including grade (P= 0.038), stage (P= 0.005), and metastatic status (P= 0.014). No correlation was observed with age (P= 0.196) or with preoperative prostate-specific antigen level (P= 0.322). Although the frequency of ERG-positive cases in Japanese PCa patients (20.1%) was lower than that reported in a PCa cohort in Western countries (approximately 50%), our study demonstrates that the clinical utility of ERG detection at the protein level can serve as an ancillary tool for diagnosing PCa in the Japanese population. © 2011 The Authors. Pathology International

Hepatic steatosis is not always a contraindication for cadaveric liver transplantation (Article)

Deroose, J.P. — 2011-06-01T00:00:00Z

Background: Macrovesicular steatosis is assumed to be an important risk factor for early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT). Aim: To evaluate the impact of steatosis in combination with other risk factors on the outcome of OLT. Methods: The degree of steatosis was analysed in 165 consecutive OLTs and was classified by histological examination as non (M0), mild (<30%, M1), moderate (30-60%, M2) or severe steatosis (>60%, M3). Recipients were analysed for EAD. Results: EAD was observed in 28% of patients with M0, 26% with M1, 53% with M2 and 73% with M3 (P < 0.001). Patients with EAD had a significantly shorter graft survival after liver transplantation (P = 0.005) but did not correlate with survival. In multivariate regression analysis, the grade of steatosis, donating after cardiocirculatory death (DCD) grafts and duration of cold ischaemia time were significantly associated with EAD (P < 0.001, P = 0.01 and P = 0.001, respectively). Conclusion: Livers with severe (M3) steatosis from DCD donors, combined with a prolonged CIT have a high risk for developing EAD which is correlated with shorter graft survival. Therefore M3 livers should only be considered for OLT in selected recipients without the presence of additional risk factors.

Placental vascularization in early onset small for gestational age and preeclampsia (Article)

Oppenraaij, R.H.F. van — 2011-06-01T00:00:00Z

The objective was to determine whether chorionic villous vascularization is diminished in cases of early onset (<34 weeks) small for gestational age (SGA) and/or preeclampsia (PE). Placental morphometrical measurements were performed in 4 gestational-age-matched groups complicated by SGA, SGA with PE, PE, and spontaneous preterm delivery without SGA or PE as the reference group. Using a video image analysis system, in randomly selected intermediate and terminal villi, the stromal area and the following villous vascular parameters were manually traced and analyzed: number of total, centrally and peripherally localized vessels, vascular area, and vascular area density. No differences were observed in intermediate and terminal villous vascular area. Preeclampsia was associated with smaller terminal villous stromal area (reference 2299 μm2, SGA 2412 μm2, SGA + PE 2073 μm2, and PE 2164 μm2, P =.011), whereas SGA was associated with an increased terminal villous vascular area density (reference 26.1%, SGA 35.7%, SGA + PE 33.4%, and PE 32.0%, P =.029). Compared with preserved flow, lower terminal villous vascular area density was found in cases with absent or reversed end-diastolic (ARED) umbilical artery flow (39.3% vs 30.3%, P =.013). These data demonstrate that villous vascularization was not influenced by PE, whereas in terminal villi an increased vascular area density was associated with SGA. Lower terminal villous vascular area density was associated with ARED flow in SGA pregnancies, indicating an increased risk of fetal compromise.

Overexpression of the natural antisense hypoxia-inducible factor-1α transcript is associated with malignant pheochromocytoma/paraganglioma (Article)

Span, P.N. — 2011-06-01T00:00:00Z

Paragangliomas (PGLs) have widely different metastastic potentials. Two different types of PGLs can be defined by expression profiling. Cluster 1 PGLs exhibit VHL and/or succinate dehydrogenase (SDH) mutations and a pseudohypoxic phenotype. RET and neurofibromatosis type 1 (NF1) mutations occur in cluster 2 tumors characterized by deregulation of the RAS/RAF/MAP kinase signaling cascade. Sporadic PGLs can exhibit either profile. During sustained hypoxia, a natural antisense transcript of hypoxia-inducible factor 1 (aHIF) is expressed. The role of aHIF in the metastatic potential of PGL has not yet been investigated. The aim was to test the hypothesis that genotype-specific overexpression of aHIF is associated with an increased metastatic potential. Tumor samples were collected from87 patients with PGL. Quantitative PCR was performed for aHIF, vascular endothelial growth factor (VEGF), aquaporin 3, cytochrome b561, p57Kip2, slit homolog 3, and SDHC. Expression was related to mutation status, benign versus malignant tumors, and metastasis-free survival. We found that both aHIF and VEGF were overexpressed in cluster 1 PGLs and inmetastatic tumors. In contrast, slit homolog 3, p57Kip2, cytochrome b561, and SDHC showed overexpression in non-metastatic tumors, whereas no such difference was observed for aquaporin 3. Patients with higher expression levels of aHIF and VEGF had a significantly decreased metastasis free survival. Higher expression levels of SDHC are correlated with an increased metastasis-free survival. In conclusion, we not only demonstrate a higher expression of VEGF in cluster 1 PGL, fitting a profile of pseudohypoxia and angiogenesis, but also of aHIF. Moreover, overexpression of aHIF and VEGF marks a higher metastatic potential in PGL.

Chemotherapy followed by surgery versus surgery alone in patients with resectable oesophageal squamous cell carcinoma: Long-term results of a randomized controlled trial (Article)

Boonstra, J.J. — 2011-05-19T00:00:00Z

Background: This is a randomized, controlled trial of preoperative chemotherapy in patients undergoing surgery for oesophageal squamous cell carcinoma (OSCC). Patients were allocated to chemotherapy, consisting of 2-4 cycles of cisplatin and etoposide, followed by surgery (CS group) or surgery alone (S group). Initial results reported only in abstract form in 1997, demonstrated an advantage for overall survival in the CS group. The results of this trial have been updated and discussed in the timeframe in which this study was performed.Methods: This trial recruited 169 patients with OSCC, 85 patients assigned to preoperative chemotherapy and 84 patients underwent immediate surgery. The primary study endpoint was overall survival (OS), secondary endpoints were disease free survival (DFS) and pattern of failure. Survival has been determined from Kaplan-Meier curves and treatment comparisons made with the log-rank test.Results: There were 148 deaths, 71 in the CS and 77 in the S group. Median OS time was 16 months in the CS group compared with 12 months in the S group; 2-year survival rates were 42% and 30%; and 5-year survival rates were 26% and 17%, respectively. Intention to treat analysis showed a significant overall survival benefit for patients in the CS group (P = 0.03, by the log-rank test; hazard ratio [HR] 0.71; 95%CI 0.51-0.98). DFS (from landmark time of 6 months after date of randomisation) was also better in the CS-group than in the S group (P = 0.02, by the log-rank test; HR 0.72; 95%CI 0.52-1.0). No difference in failure pattern was observed between both treatment arms.Conclusions: Preoperative chemotherapy with a combination of etoposide and cisplatin significantly improved overall survival in patients with OSCC.

The predictive value of immunohistochemical markers in untreated Wilms' tumour: are they useful? (Article)

Ghanem, M.A. — 2011-05-19T00:00:00Z

Purpose: This study reevaluates the potential role of different tumour markers as prognostic indicators in untreated nephroblastoma. Methods: Expression of a broad panel of tumour markers was investigated by means of immunohistochemical analysis in 43 WT patients. Patients were treated by radical nephrectomy and had a mean follow-up of 11.9 years. Results: Generally, all the tumour markers studied were expressed in normal kidney tissue and at variable levels in the three cell types of WT (blastema, epithelium and stroma). Immunoreactive blastemal (Bcl-X, Bcl-2 and CD44s) and epithelial (Bcl-X, Bcl-2 and MIB-1) cells were present in the majority of tumours. No correlation was found between their expression and pathological stages. Univariate analysis showed that blastemal WT-1, TGF-α, VEGF, MIB-1 and p27 Kip1 were indicative for clinical progression. In a multivariate analysis, WT-1 protein expression by blastemal cells was an independent prognostic marker for clinical progression. Conclusions: The blastemal WT-1, TGF-α, VEGF, MIB-1 and p27Kip1 expression correlate with clinical progression in untreated nephroblastoma. Therefore, their expression may be of value in identifying patients with a high propensity to develop distant metastases.

Chlamydia trachomatis and placental inflammation in early preterm delivery (Article)

Rours, G.I.J.G. — 2011-05-01T00:00:00Z

Chlamydia trachomatis may infect the placenta and subsequently lead to preterm delivery. Our aim was to evaluate the relationship between the presence of Chlamydia trachomatis and signs of placental inflammation in women who delivered at 32 weeks gestation or less. Setting: placental histology and clinical data were prospectively obtained from 304 women and newborns at the Erasmus MC-Sophia, Rotterdam, the Netherlands. C. trachomatis testing of placentas was done retrospectively using PCR. C. trachomatis was detected in 76 (25%) placentas. Histological evidence of placental inflammation was present in 123 (40%) placentas: in 41/76 (54%) placentas with C. trachomatis versus 82/228 (36%) placentas without C. trachomatis infection (OR 2.1, 95% CI 1.2-3.5). C. trachomatis infection correlated with the progression (P = 0.009) and intensity (P = 0.007) of materno-fetal placental inflammation. C. trachomatis DNA was frequently detected in the placenta of women with early preterm delivery, and was associated with histopathological signs of placental inflammation.

The prevalence of premalignant gastric lesions in asymptomatic patients: Predicting the future incidence of gastric cancer (Article)

Hoed, C.M. den — 2011-05-01T00:00:00Z

Background: Helicobacter pylori is the main risk-factor for gastric cancer through a cascade from gastritis through atrophic gastritis (AG), intestinal metaplasia (IM), dysplasia (DYS) to malignancy. The presence of these lesions in the general population predicts the gastric cancer incidence in the coming decades. Prevalence data are mostly obtained from serological studies and endoscopy data in symptomatic patients. Aim: To investigate the prevalence of H. pylori infection and its related gastric changes in asymptomatic subjects. Methods: 383 Patients undergoing routine colonoscopy were included. All subjects underwent upper GI endoscopy and completed the Gastrointestinal Symptom Rating Scale (GSRS). Biopsies were taken from antrum and corpus. Results: H. pylori infection was present in 22%. Non-Caucasian subjects had a significantly higher H. pylori prevalence (p < 0.001). AG, IM and DYS were together found in 9.3% of subjects. Subjects with AG, IM or DYS were significantly older (p < 0.001). No differences were found with respect to gender, presence of GI symptoms as scored by GSRS, lifestyle and medication use. Conclusions: The prevalence of premalignant gastric lesions is considerable in general Western population with increasing age as the main risk factor. One time screening for premalignant lesions at the age of 60 years is a reasonable strategy since the numbers found imply that gastric cancer will remain a prevalent disease.

Inter-observer variation in the histological diagnosis of polyps in colorectal cancer screening (Article)

Putten, P. van — 2011-05-01T00:00:00Z

Aim: To determine the inter-observer variation in the histological diagnosis of colorectal polyps. Methods and results: Four hundred and forty polyps were randomly selected from a colorectal cancer screening programme. Polyps were first evaluated by a general (324 polyps) or expert (116 polyps) pathologist, and subsequently re-evaluated by an expert pathologist. Conditional agreement was reported, and inter-observer agreement was determined using kappa statistics. In 421/440 polyps (96%), agreement for their non-adenomatous or adenomatous nature was obtained, corresponding to a very good kappa value of 0.88. For differentiation of adenomas as non-advanced and advanced, consensus was obtained in 266/322 adenomas (83%), with a moderate kappa value of 0.58. For the non-adenomatous or adenomatous nature, both general and expert pathologists, and expert pathologists between each other, showed very good agreement {kappa values of 0.89 [95% confidence interval (CI) 0.83-0.95] and 0.86 (95% CI 0.73-0.98), respectively}. For categorization of adenomas as non-advanced and advanced, moderate agreement was found between general and expert pathologists, and between expert pathologists [kappa values of 0.56 (95% CI 0.44-0.67) and 0.64 (95% CI 0.43-0.85), respectively]. Conclusions: General and expert pathologists demonstrate very good inter-observer agreement for differentiating non-adenomas from adenomas, but only moderate agreement for non-advanced and advanced adenomas. The considerable variation in differentiating non-advanced and advanced adenomas suggests that more objective criteria are required for risk stratification in screening and surveillance guidelines.

Down-regulation of oestrogen receptor-β associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas (Article)

Esposito, F. — 2011-05-01T00:00:00Z

Oestrogen exposure has been linked to a risk for the development of testicular germ cell cancers. The effects of oestrogen are now known to be mediated by oestrogen receptor-α (ERα) and ERβ subtypes, but only ERβ has been found in human germ cells of normal testis. However, its expression was markedly diminished in seminomas, embryonal cell carcinomas and mixed germ cell tumours, but remains high in teratomas. PATZ1 is a recently discovered zinc finger protein that, due to the presence of the POZ domain, acts as a transcriptional repressor affecting the basal activity of different promoters. We have previously described that PATZ1 plays a crucial role in normal male gametogenesis and that its up-regulation and mislocalization could be associated with the development of testicular germ cell tumours. Here we show that ERβ interacts with PATZ1 in normal germ cells, while down-regulation of ERβ associates with transcriptional co-regulator PATZ1 delocalization in human testicular seminomas. In addition, we show that the translocation of PATZ1 from the cytoplasm into the nucleus is regulated by cAMP, which also induces increased expression and nuclear localization of ERβ, while this effect is counteracted by using the anti-oestrogen ICI 182-780.

Inter-observer variation in the histological diagnosis of polyps in colorectal cancer screening (Article)

Putten, P. van — 2011-05-01T00:00:00Z

Mobilization of hepatic mesenchymal stem cells from human liver grafts (Article)

Pan, Q. — 2011-05-01T00:00:00Z

Extensive studies have demonstrated the potential applications of bone marrow-derived mesenchymal stem cells (BM-MSCs) as regenerative or immunosuppressive treatments in the setting of organ transplantation. The aims of the present study were to explore the presence and mobilization of mesenchymal stem cells (MSCs) in adult human liver grafts and to compare their functional capacities to those of BM-MSCs. The culturing of liver graft preservation fluids (perfusates) or end-stage liver disease tissues resulted in the expansion of MSCs. Liver-derived mesenchymal stem cells (L-MSCs) were equivalent to BM-MSCs in adipogenic and osteogenic differentiation and in wingless-type-stimulated proliferative responses. Moreover, the genome-wide gene expression was very similar, with a 2-fold or greater difference found in only 82 of the 32,321 genes (0.25%). L-MSC differentiation into a hepatocyte lineage was demonstrated in immunodeficient mice and in vitro by the ability to support a hepatitis C virus infection. Furthermore, a subset of engrafted MSCs survived over the long term in vivo and maintained stem cell characteristics. Like BM-MSCs, L-MSCs were found to be immunosuppressive; this was shown by significant inhibition of T cell proliferation. In conclusion, the adult human liver contains an MSC population with a regenerative and immunoregulatory capacity that can potentially contribute to tissue repair and immunomodulation after liver transplantation.

Misclassification of dysplasia in patients with inflammatory bowel disease: Consequences for progression rates to advanced neoplasia (Article)

Van Schaik, F.D.M. — 2011-05-01T00:00:00Z

Background: The natural behavior of flat low-grade (LGD) and indefinite dysplasia (IND) in patients with inflammatory bowel disease (IBD) remains uncertain and seems to be dependent on the interpretation of the pathologist. We studied the progression rate of flat LGD and IND to advanced neoplasia (high-grade dysplasia [HGD] or colorectal cancer [CRC]) before and after histopathological review by a panel of gastrointestinal expert pathologists. Methods: A nationwide pathology database was used to identify IBD patients with dysplasia in six Dutch university medical centers between 1990 and 2006. Medical charts of patients with recorded flat LGD or IND were reviewed. Histological slides from three university medical centers were reviewed by a panel of three expert gastrointestinal pathologists. Results: We identified 113 flat LGD patients and 26 flat IND patients. Advanced neoplasia was found in 18 flat LGD patients (16%) after a median follow-up of 48 months, resulting in a 5-year progression rate of 12%. Five IND patients (19%) developed advanced neoplasia after a median follow-up of 24 months, resulting in a 5-year progression rate of 21%. Review of 1547 histological slides from 87 patients resulted in an increase of the 5-year progression rate of flat LGD to advanced neoplasia to 37%, whereas the progression rate of IND decreased to 5%. Conclusions: A diagnosis of flat LGD that is confirmed by a panel of expert gastrointestinal pathologists is associated with a substantial risk of progression to advanced neoplasia, while confirmed IND is associated with a low risk of progression. (Inflamm Bowel Dis 2010;)

Disturbance of the microRNA pathway by commonly used lentiviral shRNA libraries limits the application for screening host factors involved in hepatitis C virus infection (Article)

Pan, Q. — 2011-04-06T00:00:00Z

RNA interference (RNAi) is widely used as a screening tool for the identification of host genes involved in viral infection. Due to the limitation of raw small interfering RNA (siRNA), we tested two commonly used short hairpin RNA (shRNA) lentiviral libraries to identify host factors involved in hepatitis C virus (HCV) infection. It was found that these shRNA library vectors caused non-specific disturbance of HCV replication that was not due to toxicity or interferon response, but related to the high shRNA levels disturbing the endogenous microRNA biogenesis. The high shRNA levels achieved with these vectors reduced the levels of mature microRNAs, including miR-122 known to promote HCV replication. Our findings extend the caution of potential off-target effects of lentiviral shRNA libraries which appear unsuitable to screen microRNA regulated phenotypes, such as HCV replication.

Treatment of vulvar intraepithelial neoplasia with topical imiquimod: Seven years median follow-up of a randomized clinical trial (Article)

Terlou, A. — 2011-04-01T00:00:00Z

Objective: Recently we reported on the efficacy of imiquimod for treating vulvar intraepithelial neoplasia (VIN) in a placebo-controlled, double-blinded randomized clinical trial (RCT). Four weeks after treatment, a complete response was observed in 35% of patients and a partial response in 46%. All complete responders remained disease-free at 12 months follow-up. In the current investigations, we assessed long-term follow-up at least 5 years after the initial RCT. Methods: Twenty-four of 26 imiquimod-treated patients who had participated in the initial RCT were seen for follow-up. Primary endpoint was durability of clinical response to imiquimod assessed by naked eye vulvar examination and histology. Long-term clinical response was correlated to lesion size before start of the initial RCT. Secondary endpoints were mental health, global quality of life, body image and sexual function in relation with long-term clinical response. Results: Median follow-up period was 7.2 years (range 5.6-8.3 years). VIN recurred in one of nine complete responders. Of the initial partial responders, two became disease-free after additional imiquimod treatment. In the other partial responders, VIN recurred at least once after the initial RCT. In long-term complete responders, lesion size at study entry was smaller and these patients had a significantly better global quality of life at follow-up than patients with residual disease and/or recurrence after imiquimod treatment. Conclusions: In case of a complete response, imiquimod is effective in the long-term. Furthermore, patients with a long-term complete response had a significantly better global quality of life than patients who recurred after imiquimod treatment.