Apoptosis, inflammatory bowel disease and carcinogenesis: overview of international and Greek experiences.

Apoptosis is critical for organ development, tissue homeostasis, the elimination of abnormal cells and the maintenance of immune homeostasis by variable regulatory mechanisms. The death of T lymphocytes following their activation involves a series of proteases (caspases), which comprise the central executioners of apoptosis. Abnormal regulation of apoptosis results in disease. T-cell resistance against apoptosis contributes to inappropriate T-cell accumulation and the perpetuation of the chronic inflammatory process in inflammatory bowel disease with potential tumourigenic effect. The use of antitumour necrosis factor-alpha, anti-interleukin-6R and anti-interleukin-12 antibodies suppresses colitis activity by induction of T-cell apoptosis, thereby having important implications for the design of effective therapeutic strategies in inflammatory bowel diseases. Contrary to international data, the incidence of cancer in Greek patients with inflammatory bowel disease appears to be low. A balance between cell proliferation (Ki-67 overexpression) and apoptosis (Bax protein overexpression) may partly explain the low incidence of cancer development in Greek inflammatory bowel disease patients.     

Cholangiocarcinoma and severe renal hypouricemia: a study of the renal mechanisms.

Hypouricemia in malignant neoplasms is rarely reported. We present a previously unreported case of cholangiocarcinoma associated with severe persistent hypouricemia (serum uric acid levels ranged from 0.07 to 0.08 mmol/L [1.16 to 1.40 mg/100 mL], and increased urate clearance (50.90 to 57.33 mL/min v a mean value in 20 normal subjects of 9.75 +/- 1.65 mL/min). High fractional urate clearance (Cus/Ccr = 0.50 to 0.58 v 0.09 +/- 0.01 in normals) was suppressed only slightly following pyrazinamide (PZA), to 0.29 versus 0.007, and was surprisingly enhanced by probenecid (PB) to 1.78 versus 0.63 in normals. No other renal tubular or metabolic abnormalities were detected. This previously unreported association of a high PZA-nonsuppressible urate excretion with a postprobenecid urate clearance exceeding glomerular filtration rate suggests that a combined renal tubular defect is responsible for hypouricemia. The patient described here provides evidence to support the presence of a presecretory reabsorptive defect in association with a "relatively high" urate secretion by the renal tubule. This report adds to the list of hypouricemic conditions and presents an important clue to elucidate urate handling mechanisms in man.     

Helicobacter pylori infection upregulates endothelial nitric oxide synthase expression and induces angiogenesis in gastric mucosa of dyspeptic patients

BACKGROUND: Helicobacter pylori (H. pylori) infection induces nitric acid (NO) overproduction through inducible NO synthase (NOS) expression, subsequent DNA damage and enhanced antiapoptosis signal transduction sequence in the human gastric mucosa, whereas its possible effect on endothelial nitric oxide synthase (eNOS) expression has not as yet been investigated. The aim of this study was to evaluate the effect of H. pylori infection in the expression of eNOS in gastric mucosa. PATIENTS AND METHODS: We prospectively studied 30 nonsmoking dyspeptic patients (12 men, 18 women, mean age 54.26+/-12.89 years). The diagnosis of H. pylori infection was based mainly on histology. The histological grading of H. pylori infection was evaluated according to the modified Sydney classification. Histological grading of eNOS expression and microvessel density as estimated by CD34 expression were determined by immunohistochemistry (degree 0-3) and correlated with H. pylori infection and histological degree of gastritis. RESULTS: Twelve patients were H. pylori-positive and 18 patients were H. pylori-negative. The two groups were matched for age (P=0.139), sex (P=0.342) and similar degree of gastritis. Intensity of eNOS and CD34 expression in the corpus and antrum were significantly correlated (P<0.001). eNOS expression was correlated with H. pylori infection in the mucosa of the body and antrum (P=0.013 and 0.037, respectively) but not with gastric inflammation and activity (P=0.848 and 0.871, respectively, for the corpus and P=0.565 and 0.793, respectively, for the antrum). H. pylori-positive patients showed higher expression of CD34-positive blood vessels in the mucosa of the antrum (P=0.048). CD34 expression was correlated with gastric inflammation and activity (P=0.03 and 0.044, respectively) in the mucosa of the antrum of H. pylori-positive patients. CONCLUSION: H. pylori infection upregulates eNOS, and induces angiogenesis, contributing to H. pylori-associated pathophysiology in gastric mucosa.     

Hepatic expression of the proliferative marker Ki-67 and p53 protein in HBV or HCV cirrhosis in relation to dysplastic liver cell changes and hepatocellular carcinoma

To evaluate hepatic expression of the nuclear proliferative marker Ki-67 and the p53 oncoprotein in hepatitis B virus (HBV)/HCV cirrhosis in relation to dysplastic liver cell changes and hepatocellular carcinoma (HCC). We studied needle liver biopsies from 107 patients with cirrhosis and no HCC (52 HBV, 55 HCV) who had been assessed for protocol studies, and 57 cirrhotic patients with HCC (40 HBV, 17 HCV). We evaluated small and large cell dysplastic changes along with the expression of Ki-67 and p53 by immunohistochemistry. The labelling index (LI) was defined as the proportion (%) of positive-stained nuclei of the 500 measured. Large and small cell dysplastic changes were observed in 12 and 9% of specimens respectively. Only small cell changes were associated with Ki-67 expression. Ki-67 LI was 5.50 +/- 5.7 in cirrhosis (13.90 +/- 3.84 in those with small cell dysplastic changes vs 4.64 +/- 4.98 in those without, P < 0.01), 10.2 +/- 5.95 in cirrhosis with HCC (P < 0.05) and 18.56 +/- 10 in HCC (P < 0.01). Neither the presence of small cell dysplastic changes nor the expression of Ki-67 was related to severity or aetiology of cirrhosis. Expression of p53 was observed in 30% of the non-tumorous and in 53% of the neoplastic tissue obtained from patients with HCC, with no differences between HCV and HBV. Ki-67 and p53 expression was associated with the tumour grade (P < 0.001). Our observations clearly demonstrate the association between the proliferation activity and the morphological changes in the cirrhotic liver from the non-dysplastic to dysplastic lesion to HCC. They also support the hypothesis that p53 alterations are a rather late event in carcinogenesis and related to HCC grade. And finally, they suggest that the final steps of hepatocarcinogenesis are common and independent of the aetiology of the chronic viral infection.     

Locoregional immunochemotherapy in primary and metastatic liver disease: meta-analysis and review of literature

BACKGROUND/AIMS: Primary and metastatic liver tumors are the most common malignancies that resist conventional chemotherapy and radiotherapy. Several immunotherapies have been attempted for cancer treatment on the basis of stimulating host immune response to tumors and recent development of combined targeting locoregional immunochemotherapy reported with promising results. However, the efficacy of this therapeutic modality is not yet widely established. METHODOLOGY: We reviewed the medical literature for publications dealing with the value of locoregional immunochemotherapy in patients with primary or metastatic liver tumors. RESULTS: We found that 5 and 7 studies have been controlled and inadequately controlled, respectively. Among 131 patients with primary liver cancer, 40 were treated with combined locoregional immunochemotherapy, and 20 with systemic immunochemotherapy, and 71 with systemic chemotherapy served as two control groups. Complete or partial response was observed in 32 out of 40 (80%) patients who received combined locoregional therapy, and in 10 out of 20 (50%) systemic immunochemotherapy controls (P = 0.03). Survival was three times higher in the patients who received combined locoregional therapy compared with systemic chemotherapy controls (18 vs. 5.6 months). Recurrence of tumor was higher in systemic immunochemotherapy controls (P = 0.003). Among 286 patients with metastatic liver disease, 180 patients were treated with combined locoregional immunochemotherapy and 106 patients with systemic immunochemotherapy. Response (complete or partial) was observed in 65 out of 98 (66.3%) patients who received combined therapy, and in 4 out of 26 (15.4%) controls (P < = 0.001). Survival was two-fold higher in the patients treated with combined therapy (21 vs. 10.5 months). Tumor recurrence was higher in the systemic immunochemotherapy controls (P < = 0.001). CONCLUSIONS: The observational studies indicate a plausible therapeutic rationale for the introduction of locoregional immunotherapy in patients with primary and metastatic liver disease.     

Multiscale photonic imaging of the native and implanted cochlea

The cochlea of our auditory system is an intricate structure deeply embedded in the temporal bone. Compared with other sensory organs such as the eye, the cochlea has remained poorly accessible for investigation, for example, by imaging. This limitation also concerns the further development of technology for restoring hearing in the case of cochlear dysfunction, which requires quantitative information on spatial dimensions and the sensorineural status of the cochlea. Here, we employed X-ray phase-contrast tomography and light-sheet fluorescence microscopy and their combination for multiscale and multimodal imaging of cochlear morphology in species that serve as established animal models for auditory research. We provide a systematic reference for morphological parameters relevant for cochlear implant development for rodent and nonhuman primate models. We simulate the spread of light from the emitters of the optical implants within the reconstructed nonhuman primate cochlea, which indicates a spatially narrow optogenetic excitation of spiral ganglion neurons.

In the case of profound sensorineural hearing impairment, cochlear implants (CIs) partially restore hearing by providing auditory information to the brain via electrical stimulation of the spiral ganglion neurons (SGNs). CIs enable speech understanding in the majority of the ∼700,000 users worldwide. However, current clinical CIs are limited by their wide current spread (1) resulting in poor coding of spectral information (2). Recently, cochlear optogenetics was proposed for stimulating the auditory nerve by light (3–10). As light can be better confined in space, the spread of excitation in the cochlea is lower (3, 9–11) and, hence, future optical CIs (oCIs) promise improved speech comprehension—especially in noisy background—as well as greater music appreciation.For the technical development of oCIs toward a future medical device, major efforts are currently being undertaken to devise multichannel optical stimulators for the cochlea (10, 12–17). As is the case for the electrodes of current CIs, future oCIs will place multiple stimulation channels, here microscale emitters, along the tonotopic axis of the cochlea. Further development of the oCIs requires precise estimates of parameters such as scala tympani size, optimal probe stiffness, and bending radius. Moreover, cochlear optogenetics employs gene transfer to the SGNs for which adeno-associated viruses (AAVs) seem promising candidate vectors (3–5, 8). AAV delivery has used injection of virus suspension via the round window (4, 8) or directly into Rosenthal’s canal (5, 9, 10). Therefore, the volumes of Rosenthal’s canal and the scalae tympani, vestibuli and media needed to be evaluated in order to estimate the required virus load for injection. Finally, the sensorineural status of the cochlea is highly relevant for future gene therapy and CI stimulation, and hence, quantitative imaging of sensory cells and neurons is an important objective.Here, we employed multiscale X-ray phase-contrast tomography (XPCT) and light-sheet fluorescence microscopy (LSFM) and provide an analysis of cochlear morphology for mice, rats, gerbils, guinea pigs, and marmosets. Each of these animal models offers unique advantages for auditory research. The mouse is readily available for genetic manipulation (e.g., ref. 18). Channelrhodopsin-expressing transgenic lines are available also for rats (19, 20) that offer a larger cochlea and can carry heavier implants than mice (21–24). Similarly, gerbils and guinea pigs are established rodent models for auditory research with larger-sized cochleae. Moreover, gerbils, which have low-frequency hearing more similar to humans, have already been employed for cochlear optogenetics (5, 9, 10, 24). Finally, we analyzed the cochlea of the common marmoset, as an established nonhuman primate model for auditory research (e.g., refs. 25, 26). Marmosets possess a rich vocalization repertoire and share a pitch perception mechanism with humans (27). Therefore, we compared cochlear insertion of newly designed oCIs with electrical cochlear implants (eCI) and modeled the optical spread of excitation in the marmoset cochlea.