Remote ischemic preconditioning stimulus decreases the expression of kinin receptors in human neutrophils.

BACKGROUND: Remote ischemic preconditioning (RIPC) has been shown to reduce ischemic-reperfusion injury and is induced by brief forearm ischemia. Kinins are known to be involved in RIPC and act via the G protein coupled B1 and B2 receptors. Interaction of the kinins with their respective receptors causes receptor internalization, thereby reducing the potential for further activation. This may be critical for the protective effect of RIPC and if so, we hypothesized, would significantly decrease the expression of kinin receptors on the surface of neutrophils. METHODS: The study was performed on five healthy human volunteers. The left forearm was rendered ischemic for three 5-min periods, each separated by 5 min of reperfusion. Three venous blood samples were taken from the right arm, one before and two after RIPC. Neutrophil isolation, immunofluorescence labeling, and confocal microscopy were performed. Mean pixel intensity data were generated using a fixed circular area of interest (AOI, 40×40 µm). For every image, the AOI was placed over a cell and the mean pixel intensity was recorded. The mean intensity was expressed as pixel×10(2)/µm(2) and presented as mean±SEM. Immunofluorescence at the different time points was compared by one way analysis of variance with Bonferroni's post-hoc test. A P value<0.05 was considered significant. RESULTS: The mean pixel intensity for kinin B1 receptors was decreased at 24 h after RIPC compared with both baseline and 15 min after RIPC (P<0.001). Similarly, the intensity for B2 receptor labeling on neutrophils was significantly decreased 24 h after RIPC compared with the baseline value (P<0.001). CONCLUSIONS: RIPC decreases expression of kinin receptors on circulating human neutrophils. Reduction in kinin surface receptors suggests internalization of receptors and is consistent with the concepts of kinin receptor activation and their role in RIPC.

Kallikreins, kininogens and kinin receptors on circulating and synovial fluid neutrophils: role in kinin generation in rheumatoid arthritis.

OBJECTIVES: Neutrophils traffic into and have the capacity to generate kinins in SF of RA patients. The aim of this study was to assess the expression of kallikreins, kininogens and kinin receptors in circulating and SF neutrophils, as well as synovial tissue of RA patients, and to assess kinin generation in SF. METHODS: Neutrophils were isolated from blood and SF of RA patients and blood of healthy volunteers. Expression of kallikreins, kininogens and kinin receptors in neutrophils and synovial tissue was assessed by immunocytochemistry using specific antibodies, with visualization by brightfield and confocal microscopy. Levels of basal and generated kinins in SF of RA patients were measured by ELISA. RESULTS: Kinin labelling was significantly reduced, indicating the loss of the kinin moiety from kininogen on circulating (P < 0.001) and SF neutrophils (P < 0.05) of RA patients. Immunolabelling of tissue kallikrein was also decreased, whereas kinin B(1) and B(2) receptor expression was increased in circulating and SF neutrophils of RA patients. Immunolabelling of kallikreins and kinin receptor proteins was similar in RA and normal synovial tissues. The basal kinin level in SF of RA patients was 5.7 +/- 6.1 ng/ml and the mean concentration of kinins generated in vitro was 80.6 +/- 56.3 ng/ml. The capacity for kinin generation was positively correlated with measures of disease activity. CONCLUSIONS: Kallikrein-kinin proteins on neutrophils play an important role in kinin generation and the pathophysiology of RA. Specific kallikrein and kinin receptor antagonists may be useful as IA therapies for inflamed joints.

Expression of kallikrein-related peptidases (KRP/hK5, 7, 6, 8) in subtypes of human lung carcinoma.

Lung cancer is currently the leading cause of cancer mortality worldwide. Expression of kallikrein-related peptidases (KRP/hK/KLK) may be induced during lung carcinogenesis. To test the hypothesis that KRP/hK, previously identified in the skin (KRP/hK5, 7) and brain (KRP/hK6, 8), are expressed in lung tumours, experiments were designed to investigate their localization in four malignant sub-types of human lung cancer. Using specific antibodies, expression of these KRP/hK was determined in archived lung tumour sections of the four subtypes, and in normal skin, brain, lung and submandibular gland tissue sections. Immunoperoxidase labelled sections were visualized by brightfield microscopy. In the squamous cell carcinoma, small cell carcinoma and carcinoid tumour, 40-90% of the malignant cells showed positive cytoplasmic labelling for KRP/hK5, 7, 6 and 8 (intensity grade 2+/3+). In the adenocarcinoma there was no cytoplasmic labelling for any of the KRP/hK, but the nuclei of 20% of the tumour cells were labelled for KRP/hK5, 7 and 8 (intensity grade 2+/3+). Further studies are required to determine the functional significance of the expression of KRP/hK in human lung carcinomas, and whether any of these proteins may be potential biomarkers for specific sub-types of lung cancer.

Current status of tissue kallikrein inhibitors: importance in cancer.

The past decade has seen an increase in the understanding of the structure and function of protease inhibitors. The molecular basis of the interaction between a variety of biological substrates or synthetic inhibitors and serine proteases of the kallikrein family has provided insights into inhibitor protein-protease reactive site interactions, which have proved of value in the design of new kallikrein inhibitors. This review focuses on the current understanding of the functional status of kallikrein inhibitors, which include a variety of molecules derived from plant, reptile and mammalian sources, as well as synthetic agents.

Human papillomavirus and gene mutations in head and neck squamous carcinomas.

BACKGROUND: Human papillomavirus (HPV) infection is implicated as an aetiological factor in head and neck squamous carcinomas (HNSCC), especially in the tonsils of the oropharyngeal region. This study investigates the frequency of HPV infection, p16 and p53 tumour profile and mutations in epidermal growth factor receptor (EGFR), Kirsten RNA Associated Rat Sarcoma 2 Virus (KRAS) and B-Raf proto-oncogene serine/threonine protein kinase (BRAF) genes in tonsillar and non-tonsillar HNSCCs and correlates with clinical outcome and histopathological parameters in previously unstudied cohort of patients. METHODS: A retrospective clinical study was performed utilising the demographic data and pathological specimens from 60 out of 726 head and neck cancer patients. Smoking and alcohol history, tumour staging, treatment and outcomes were recorded. Histopathology and immunochemistry for p16 and p53 was performed and HPV DNA was detected with polymerase chain reaction. Genomic DNA from all cancers were analysed for somatic mutations of EGFR, BRAF and KRAS genes. RESULTS: 20 (33%) of 60 cases were tonsillar squamous carcinomas and 38 (66%) were non-tonsillar. 19 (95%) of the 20 tonsillar cancers and three (8%) of 38 non-tonsillar patients were patients who were HPV 16-positive. Nine (47%) of the 19 HPV 16-positive tonsillar cases were p16 positive. Gene mutations were rare. There was a statistically significant (P < 0.05) improved survival of patients with HPV positive tonsillar tumours, younger age and non-smokers. CONCLUSION: Although limited in numbers, this study reinforces the role of HPV infection in HNSCC and its association with a more favourable clinical course in younger non-smokers worldwide. Gene mutation frequencies were low in all cancers tested and routine testing not recommended.

More than just counting eosinophils: proximal oesophageal involvement and subepithelial sclerosis are major diagnostic criteria for eosinophilic oesophagitis.

BACKGROUND: According to American Gastroenterological Association Institute criteria, the diagnosis of eosinophilic oesophagitis (EOE) requires clinicopathological correlation. In the appropriate clinical context, a high eosinophil count (HEC, defined as >or=15/HPF) is considered pathological evidence of EOE. However, HEC may not always be identified in biopsies given its patchy distribution, and there may be histological overlap between EOE and gastro-oesophageal reflux disease (GORD) in the distal oesophagus. AIMS: To evaluate the utility of subepithelial sclerosis and HEC in proximal oesophageal biopsies as additional diagnostic criteria. METHODS: Cases between 2004 and 2008 with paired proximal and distal oesophageal biopsies and the mention of eosinophils in the reports were retrieved from PathWest Queen Elizabeth II Medical Centre archives. Biopsies were reviewed and assessed for eosinophilic count and presence of subepithelial stroma and sclerosis. A final diagnosis was made after review of both biopsy and clinical details. RESULTS: There were 23 cases of EOE and 20 cases of GORD in an adult cohort. In comparison to GORD, cases of EOE had significantly higher eosinophil counts in proximal (39.4 vs 0.6 eosinophils/HPF) and distal biopsies (35.6 vs 1.9), with HEC in proximal biopsies a feature exclusive to EOE (83% vs 0%). Subepithelial sclerosis was identified in at least one biopsy in 74% of EOE and in only a single case of GORD. CONCLUSIONS: HEC in proximal oesophageal biopsies and subepithelial sclerosis should be considered major diagnostic findings in EOE.

Papillary fibroelastoma of the interventricular septum: mimicking a cardiac myxoma.

Papillary fibroelastomas are benign cardiac tumors that involve cardiac valves. These tumors are usually asymptomatic and are found incidentally during cardiac surgery or during echocardiographic evaluation in a patient who exhibits cardiac symptoms. However, these tumors may cause major thromboembolic complications. Herein, we describe the surgical management of a patient who had an unusual appearance and location of a papillary fibroelastoma that was attached to the interventricular septum.

Expression of tissue and plasma kallikreins and kinin B1 and B2 receptors in lung cancer.

Tissue kallikrein (hK1) and plasma kallikrein (PK, hKB1) are serine proteases that produce biologically active kinin peptides from endogenous kininogen substrates. There is evidence linking the kallikreins and the mitogenic kinin peptides to carcinogenesis. The aim of this study was to investigate the expression of tissue prokallikrein (pro-hK1), plasma prekallikrein (PPK, pre-hKB1) and kinin B1 and B2 receptor proteins in different subtypes of lung cancer. Immunohistochemistry, using specific antibodies, was performed on archived normal lung sections and sections from adenocarcinomas, squamous cell carcinomas, large cell carcinomas, small cell carcinomas and carcinoid tumours of the lung. Immunoperoxidase labelling was visualised by brightfield microscopy and immunofluorescence labelling by confocal microscopy. Extensive cytoplasmic expression of pro-hK1 and PPK was observed, which was similar in small cell and non-small cell tumours. However, nuclear labelling for the kallikreins was absent or limited. The kinin B1 and B2 receptors were highly expressed in the cytoplasm of all tumour types and in the nuclei of non-small cell tumours. Further studies are required to assess the functional significance of the expression of hK1, PK and kinin receptors in lung tumours, and whether any of these proteins may be potential biomarkers for specific subtypes of lung carcinoma.

Novel expression of kallikreins, kallikrein-related peptidases and kinin receptors in human pleural mesothelioma.

Malignant mesothelioma is an aggressive cancer of the pleura that is causally related to exposure to asbestos fibres. The kallikrein serine proteases [tissue (hK1) and plasma (hKB1) kallikreins, and kallikrein-related peptidases (KRP/hK2-15)] and the mitogenic kinin peptides may have a role in tumourigenesis. However, it is not known whether hK1, hKB1, KRP/hK proteins or kinin receptors are expressed in pleural mesotheliomas. The expression of hK1, hKB1, KRP/hK2, 5, 6, 7, 8 and 9, and kinin B(1) and B(2) receptors was assessed in archived selected normal tissue and mesothelioma tumour sections by immunoperoxidase and immunofluorescence labelling. hK1, hKB1 and kinin B(1) and B(2) receptors were expressed in malignant cells of the epithelioid and sarcomatoid components of biphasic mesothelioma tumour cells. The percentage of cells with cytoplasmic and nuclear labelling and the intensity of labelling were similar for hK1, hKB1 and the kinin receptors. KRP/hK2, 6, 8 and 9 were also expressed in the cytoplasm and nuclei of mesothelioma cells, whereas KRP/hK5 and hK7 showed predominantly cytoplasmic localisation. This is a first report, but further studies are required to determine whether these proteins have a functional role in the pathogenesis of mesothelioma and/or may be potential biomarkers for pleural mesothelioma.

Superior vena cava obstruction by tumour thrombus in invasive thymoma: diagnosis and surgical management.

Thymomas are common mediastinal tumours. We report a rare case of thymoma invasion into the superior vena cava with resultant venous obstruction. The tumour was resected. The superior vena cava and left brachiochephalic vein were reconstructed with autologous pericardial patch.