Sex difference in circulating soluble form of ACE2 protein in moderate and severe COVID-19 and healthy controls

Introduction

Membrane-bound angiotensin-converting enzyme-2 (ACE2) in epithelial cells is the main receptor for SARS-CoV-2. The extracellular portion of ACE2 may be shedded to plasma in which process ADAM17 (a disintegrin and metalloproteinase 17) is important. Results on the relationship between circulating levels of the soluble form of ACE2 (sACE2) and disease severity are inconclusive. This study investigates if sACE2 concentration correlates with COVID-19 severity, and whether this is affected by sex.

Materials and methods

Soluble form of ACE2 was analyzed in three groups: 104 patients (23 women and 81 men) with severe COVID-19 admitted to an intensive care unit (ICU), patients with moderate COVID-19 who required hospital care (n = 19, 4 women and 15 men), and age and sex matched healthy controls (n = 20, 4 women and 16 men). Blood samples were collected at hospital admission between 18 March 2020, and 3 May 2021, and at follow-up between 27 October 2020, and 19 October 2021. Circulating sACE2 (μg/L) was measured in EDTA plasma with a sensitive enzyme-linked immunosorbent assay. Additionally, CRP, ferritin, and lymphocyte count were analyzed during hospital stay.

Results

In total, 23 patients (22%) died in the ICU. When comparing healthy controls [mean age 58.1 (SD 11.4) years] and patients with moderate COVID-19 [mean age 61.0 (SD 13.2) years] with patients in the ICU [mean age 63.6 (SD 11.6) years], we found that sACE2 concentration decreased (70% reduction) with disease severity in men (p = 0.002) but increased 3.7-fold with severity in women (p = 0.043), suggesting a sex-related difference in how COVID-19 severity is related to sACE2 concentration. Moreover, we identified a relationship between inflammatory biomarkers and sACE2 concentration during the intensive care treatment, such that higher CRP and higher ferritin concentration correlated with lower sACE2 concentration in men.

Conclusion

The decrease in sACE2 concentration, selectively in men, in severe COVID-19 is of pathophysiological interest since men are affected more severely by the disease compared to women. Additionally, the inflammatory biomarkers, CRP and ferritin, correlated inversely with sACE2 concentration, suggesting a role in severe disease. Our findings imply that sACE2 is a possible biomarker of disease severity in a sex-specific manner.

Checkpoint Inhibition Causing Complete Remission of Metastatic Combined Hepatocellular-Cholangiocarcinoma after Hepatic Resection

Combined hepatocellular-cholangiocarcinoma (CHC) is a rare type of primary liver cancer, speculated to arise from hepatic progenitor cells, and with a worse prognosis than hepatocellular carcinoma (HCC). Serum alpha-fetoprotein (AFP) levels may be one prognostic factor. It has been suggested that checkpoint inhibition might be useful in the treatment of HCC where there is an increased expression of PD-1 and PD-L1 in the microenvironment. Its effect on CHC is unknown. We report a case with a large CHC, which was radically resected, but the 53-year-old female patient subsequently developed pulmonary metastases. Histology demonstrated low-differentiated CHC without microsatellite instability. Treatment with sorafenib was started but was stopped due to angioedema. Under subsequent gemcitabine/cisplatin treatment, the metastatic disease progressed with rising AFP levels. A third-line treatment with pembrolizumab was then started, 2 mg/kg b.w. i.v. every third week for 6 months. This resulted in a radiologically complete remission of the pulmonary metastases and AFP levels were normalized (<10 μg/L) from a level of 1,790 μg/L before treatment. The patient developed immune-related adverse events (AEs) including diarrhea and hepatitis. These AEs were successfully treated with prednisolone and mycophenolate mofetil, and they were eventually resolved. There are no signs of cancer recurrence neither in the liver nor in the lungs at 33 months after the start of the checkpoint inhibition treatment, and the patient is doing well. Further study is urgently needed on the role of checkpoint inhibition therapy in liver cancer.

Roles of cell fusion, hybridization and polyploid cell formation in cancer metastasis

Cell-cell fusion is a normal biological process playing essential roles in organ formation and tissue differentiation, repair and regeneration. Through cell fusion somatic cells undergo rapid nuclear reprogramming and epigenetic modifications to form hybrid cells with new genetic and phenotypic properties at a rate exceeding that achievable by random mutations. Factors that stimulate cell fusion are inflammation and hypoxia. Fusion of cancer cells with non-neoplastic cells facilitates several malignancy-related cell phenotypes, e.g., reprogramming of somatic cell into induced pluripotent stem cells and epithelial to mesenchymal transition. There is now considerable in vitro, in vivo and clinical evidence that fusion of cancer cells with motile leucocytes such as macrophages plays a major role in cancer metastasis. Of the many changes in cancer cells after hybridizing with leucocytes, it is notable that hybrids acquire resistance to chemo- and radiation therapy. One phenomenon that has been largely overlooked yet plays a role in these processes is polyploidization. Regardless of the mechanism of polyploid cell formation, it happens in response to genotoxic stresses and enhances a cancer cell’s ability to survive. Here we summarize the recent progress in research of cell fusion and with a focus on an important role for polyploid cells in cancer metastasis. In addition, we discuss the clinical evidence and the importance of cell fusion and polyploidization in solid tumors.

Donor Monoclonal Gammopathy May Cause Lymphoproliferative Disorders in Solid Organ Transplant Recipients

Prior research on donor monoclonal gammopathy of undetermined significance (MGUS) has been inadequate regarding the risk for lymphoproliferative disease in solid organ transplantation recipients. Seven organ recipients from two different donors developed lymphoproliferative disease. The origin of the malignancy was determined by use of microsatellite analysis, and the plasma of the two donors was analyzed with the use of electrophoresis. The clinical courses of the seven recipients were followed for 36-60 months. One donor transmitted lymphoplasmacytic lymphoma to two kidney recipients and MGUS to a liver recipient, all IgMκ. A second donor caused IgGλ myeloma in two kidney and one liver recipient, and IgGλ gammopathy in a heart recipient. Transplant nephrectomy was performed in three kidney recipients and remission was achieved. The fourth kidney recipient has kept the graft and the disease has progressed. The liver recipient died from myeloma. There were no clinical signs of lymphoproliferative disease in the donors, but retrospective serum analyses showed M-components, IgMκ (37 g/L) and IgGλ (8 g/L). Donors with MGUS may cause donor-transmitted malignancies via passenger lymphocytes/plasma cells in solid organ recipients. The results call for a large register study of the incidence of donor MGUS and lymphoproliferative disease in their recipients.

MicroRNA in exosomes isolated directly from the liver circulation in patients with metastatic uveal melanoma

Background

Uveal melanoma is a tumour arising from melanocytes of the eye, and 30 per cent of these patients develop liver metastases. Exosomes are small RNA containing nano-vesicles released by most cells, including malignant melanoma cells. This clinical translational study included patients undergoing isolated hepatic perfusion (IHP) for metastatic uveal melanoma, from whom exosomes were isolated directly from liver perfusates. The objective was to determine whether exosomes are present in the liver circulation, and to ascertain whether these may originate from melanoma cells.

Methods

Exosomes were isolated from the liver perfusate of twelve patients with liver metastases from uveal melanoma undergoing IHP. Exosomes were visualised by electron microscopy, and characterised by flow cytometry, Western blot and real-time PCR. Furthermore, the concentration of peripheral blood exosomes were measured and compared to healthy controls.

Results

The liver perfusate contained Melan-A positive and RNA containing exosomes, with similar miRNA profiles among patients, but dissimilar miRNA compared to exosomes isolated from tumor cell cultures. Patients with metastatic uveal melanoma had a higher concentration of exosomes in their peripheral venous blood compared to healthy controls.

Conclusions

Melanoma exosomes are released into the liver circulation in metastatic uveal melanoma, and is associated with higher concentrations of exosomes in the systemic circulation. The exosomes isolated directly from liver circulation contain miRNA clusters that are different from exosomes from other cellular sources.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-962) contains supplementary material, which is available to authorized users.

Macrophage Infiltration in Tumor Stroma is Related to Tumor Cell Expression of CD163 in Colorectal Cancer

The scavenger receptor, CD163, is a macrophage-specific marker. Recent studies have shown that CD163 expression in breast and rectal cancer cells is associated with poor prognosis. This study was conducted to evaluate the relationship between CD163 expression as a macrophage trait in cancer cells, and macrophage infiltration and its clinical significance in colorectal cancer. Immunostaining of CD163 and macrophage infiltration were evaluated in paraffin-embedded specimens, earlier analyzed for CD31, D2-40 and S-phase fraction, from primary tumors and normal colorectal mucosa of 75 patients with colorectal carcinoma. The outcomes were analyzed in relation to clinical-pathological data. CD163 expression was positive in cancer cells in 20 % of colorectal cancer patients and was related to advanced tumor stages (P = 0.008) and unfavorable prognosis (p = 0.001). High macrophage infiltration was related to shorter survival and positive CD163 expression in tumor cells. The prognostic impact of macrophage infiltration was independent of tumor stage and CD163 expression in cancer cells (p = 0.034). The expression of macrophage phenotype in colorectal cancer cells is associated with macrophage density in tumor stroma and lower survival rates. Macrophage infiltration has an independent prognostic impact on mortality in colorectal cancer. In accordance with previous experimental studies, these findings provide new insights into the role of macrophages in colorectal cancer.

Expression of macrophage antigens by tumor cells

Macrophages are a heterogeneous cell population of the myeloid linage derived from monocytes. These cells show two different polarization states, M1 and M2 macrophages in response to different micro environmental signals. Tumor associated macrophages (TAM) represent the M2 type and promote tumor progression. These cells express antigens that more or less are specific for macrophages like: CD14, CD68, MAC387, CD163, and DAP12. In a series of recent studies it is shown that cancer cells may express these antigens and CD163, MAC387 and DAP12 may be expressed by e.g. breast cancer cells. Thus, 48% of the breast cancers expressed CD163 that is a scavenger receptor normally expressed by macrophages alone. The corresponding figure for rectal cancer is 31%. The expression of CD163 is correlated to early distant recurrence in breast cancer and local recurrence in rectal cancer and reduced survival time in both conditions. Expression of macrophage antigens in breast- and colorectal-cancers may have a prognostic relevance in clinical praxis. One explanation to these findings is that resemblance with macrophages may indicate a more invasive phenotype due to genetic exchange between the primary tumor cells and associated macrophages. This is further supported by the finding that expression of DAP12, a macrophage fusion receptor, in breast cancer is associated with an advanced tumor grade and higher rates of skeletal and liver metastases and overall shorter distant recurrence free survival. Another explanation to the changed phenotype is a genetic exchange between the cells by exosome-mediated transfer.

Expression of the macrophage antigen CD163 in rectal cancer cells is associated with early local recurrence and reduced survival time

Expression of the macrophage antigen CD163 in breast cancer cells is recently shown to be related to early distant recurrence and shortened survival. In this study, 163 patients with rectal cancer, included in the Swedish rectal cancer trial and followed up for a median of 71 months, were examined for the expression of CD163 in the primary tumors. The cancer cells expressed CD163 in the primary tumors in 23% (n = 32) of the patients. In pretreatment biopsies from 101 patients, 10 had CD163-positive cancers and these patients had earlier local recurrence (p < 0.044) and reduced survival time (p < 0.045) compared with those with CD163-negative tumors. When studying surgical specimens from 61 patients randomized to preoperative irradiation (5 x 5 Gy delivered in 1 week), it was found that 31% were CD163 positive whereas the corresponding figure was only 17% for 78 patients who were nonirradiated (p < 0.044), which tentatively may be consistent with X-rays inducing fusion. In CD163-positive tumors there was a reduced apoptotic activity as measured with the Termina deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) technique (p = 0.018). There tended also to be an increased proliferation activity measured as an expression of Ki-67 non significant (NS). It is concluded that primary rectal cancers may express CD-163, and this phenotypic macrophage trait is related to early local recurrence, shorter survival time and reduced apoptosis. Furthermore, the expression of CD163 is more common after irradiation.

Use of a virtual reality, real-time, simulation model for the training of urologists in transurethral resection of the prostate

OBJECTIVE

There is a growing need to develop surgical skills outside the operating theatre. In this study we describe the development of a virtual reality training system for practising transurethral resection of the prostate (TURP).

MATERIAL AND METHODS

A face validity study was performed using a questionnaire sent to 28 experienced urologists to find out the ideal characteristics of a simulated TURP. Based on the comments a simulator was constructed and a content validity study was then performed in which nine experienced urologists tested the simulator and answered a second questionnaire. After corrections to the simulator, a basic construct validity test was performed.

RESULTS

We have developed a computer-based simulator based on the requirements listed by 17 urologists. It consists of a modified resectoscope connected to a haptic device and supported by a frame. The software provides a virtual view of the prostatic lumen and resectoscope tip, a haptic rendering that generates force feedback and a simulation module that computes the information from the haptic device, resectoscope fluid tap and handle and the foot pedals. The software also simulates bleeding, absorption of irrigation fluid and pressure gradients. Variables are measured and presented in a result file after each "operation". Nine experienced urologists performed a content validity study and changes were made accordingly. A basic construct validity test performed by seven inexperienced students showed a significant improvement in performance after they each performed six simulated procedures.

CONCLUSION

We have developed a simulator that may be used to practise TURP and which meets most of the demands raised in a face validity study. A basic construct validity test showed improved performance after repeated practice in the simulated environment.

Systematic review of cholecystostomy as a treatment option in acute cholecystitis

OBJECTIVES

Percutaneous cholecystostomy (PC) is an established low-mortality treatment option for elderly and critically ill patients with acute cholecystitis. The primary aim of this review is to find out if there is any evidence in the literature to recommend PC rather than cholecystectomy for acute cholecystitis in the elderly population.

METHODS

In April 2007, a systematic electronic database search was performed on the subject of PC and cholecystectomy in the elderly population. After exclusions, 53 studies remained, comprising 1918 patients. Three papers described randomized controlled trials (RCTs), but none compared the outcomes of PC and cholecystectomy. A total of 19 papers on mortality after cholecystectomy in patients aged >65 years were identified.

RESULTS

Successful intervention was seen in 85.6% of patients with acute cholecystitis. A total of 40% of patients treated with PC were later cholecystectomized, with a mortality rate of 1.96%. Procedure mortality was 0.36%, but 30-day mortality rates were 15.4 % in patients treated with PC and 4.5% in those treated with acute cholecystectomy (P < 0.001).

CONCLUSIONS

There are no controlled studies evaluating the outcome of PC vs. cholecystectomy and the papers reviewed are of evidence grade C. It is not possible to make definitive recommendations regarding treatment by PC or cholecystectomy in elderly or critically ill patients with acute cholecystitis. Low mortality rates after cholecystectomy in elderly patients with acute cholecystitis have been reported in recent years and therefore we believe it is time to launch an RCT to address this issue.

Breast cancer expression of CD163, a macrophage scavenger receptor, is related to early distant recurrence and reduced patient survival

Cells of the monocyte/macrophage lineage are important for tumour cell migration, invasion and metastasis. Fusion between macrophages and cancer cells in animal models in vitro and in vivo causes hybrids with increased metastatic potential. Primary breast cancer cells were characterized for macrophage antigens to test if phenotypic resemblance to macrophages is related to early distant recurrence. Immunostaining for CD163, MAC387 and CD68 was performed in a breast cancer tissue micro array from 127 patients consequently followed up for a median of 13 years. Tumour-associated macrophages expressed all 3 antigens. The breast cancers expressed CD163 to 48%, MAC387 to 14% while CD68 was not expressed. TGF-beta staining intensity was positively related to both CD163 and MAC387 expression. Expression of CD163 in the cancer cells was compared to their DNA ploidy, Nottingham Histological Grade, TNM-stage, node state, presence of estrogen receptors and occurrence of distant metastases and survival. Cancers of a more advanced histological grade expressed CD163 to a higher extent. Cells expressing MAC387 were more common in cancers with a high proportion of CD163 positive cells. Multivariate analysis showed that expression of the macrophage antigen CD163 in breast cancer cells has a prognostic impact on the occurrence of distant metastases and reduced patient survival time.

Anticancer effect of SN-38 on colon cancer cell lines with different metastatic potential

SN-38 is an active metabolite of the topoisomerase I inhibitor irinotecan. The mechanism behind its antitumor effect in colorectal cancer is not fully understood. In this study, we examined the response of colon cancer cell lines with different metastatic potential to SN-38. The parental human colon cancer cell line KM12C and its two highly metastatic derivatives KM12SM and KM12L4a were cultivated in 5% CO2 at 37 degrees C for 24 h and then exposed to SN-38 (2.5 microg/ml) at 37 degrees C for 4, 24 and 48 h, respectively. The cell cycle was measured by flow cytometry, apoptotic activity was determined by flow cytometry and immunocytochemistry and the expression of topoisomerase I, Bax and survivin proteins were examined by Western blot. The exposure of the cells to SN-38 induced S-phase and G2 arrest (P<0.0001) and the KM12L4a cells had the highest response in a time-dependent manner (P<0.0001). The rates of apoptosis in the KM12SM (P=0.001) and KM12L4a cell lines (P=0.01) were increased time-dependently, though there was no such change in the KM12C cells. The expression of topoisomerase I protein was decreased in each cell line tested and the expression of Bax protein was increased, especially in KM12L4a. In conclusion, the effect of SN-38 on the colon cancer cell lines was mediated via conducting S-phase and G2 arrest and apoptosis. This effect was found in the cell lines with higher metastatic potentials, indicating that SN-38 can be used to treat advanced colon cancers.

Selective iNOS inhibition enhances spontaneous gallbladder motility in the Australian possum

Gallbladder inflammation is a common and painful disease. Inducible nitric oxide synthase (iNOS) plays a major role in inflammatory diseases, and iNOS inhibitors are being developed as therapeutic agents. Reports are inconsistent regarding iNOS expression in normal gallbladder. The aim of this study was to determine the effect of iNOS inhibition on spontaneous gallbladder motility. mRNA extracted from normal possum gallbladders was analysed by PCR. Gallbladder contractility was evaluated using a highly selective iNOS inhibitor AR-C102222AA (AR-C) in in vitro muscle strips (0.1-10 000 microm) and in vivo (0.1-30 micromol kg(-1)) experiments. Gene expression analysis revealed the presence of iNOS mRNA in normal gallbladder (n = 3). In vitro, AR-C (0.1-1000 micromol L(-1)) produced a concentration-dependent increase in spontaneous gallbladder contractile activity and basal tension (P < 0.05; n = 6). The maximum effect was a 1.8-fold increase in activity and 2.1-fold increase in basal tension. Pretreatment of muscle strips with tetrodotoxin (1 micromol L(-1)) did not block the AR-C-induced response (n = 5). In vivo, AR-C (30 micromol kg(-1), i.v.) increased gallbladder contraction frequency (P < 0.05; n = 8). These data suggest that iNOS is continually expressed in the normal gallbladder, which presumably releases low levels of nitric oxide and in turn may modulate spontaneous gallbladder motility. AR-C may be a beneficial treatment for patients suffering from acute cholecystitis.

Serum amino acid profile in patients with acute pancreatitis

Patients in the early phase of acute pancreatitis (AP) have reduced serum levels of arginine and citrulline. This may be of patho-biological importance, since arginine is the substrate for nitric oxide, which in turn is involved in normal pancreatic physiology and in the inflammatory process. Serum amino acid spectrum was measured daily for five days and after recovery six weeks later in 19 patients admitted to the hospital for acute pancreatitis. These patients had abnormal levels of most amino acids including arginine, citrulline, glutamine and glutamate. Phenylalanine and glutamate were increased, while arginine, citrulline, ornithine and glutamine were decreased compared to levels after recovery. NO(2)/NO(3) concentration in the urine, but not serum arginase activity, was significantly increased day 1 compared to day 5 after admission. Acute pancreatitis causes a disturbance of the serum amino acid spectrum, with possible implications for the inflammatory process and organ function both in the pancreas and the gut. Supplementation of selected amino acids could possibly be of value in this severe condition.

Expression of PRL proteins at invasive margin of rectal cancers in relation to preoperative radiotherapy

PURPOSE

PRL-3 (phosphatase of regenerating liver) is involved in metastasis of colorectal cancer; however, its therapeutic implication in cancer patients has not been studied. We investigated the relationships of PRL expression to radiotherapy (RT) in rectal cancer patients.

METHODS AND MATERIALS

Phosphatase of regenerating liver expression was immunohistochemically examined in distant (n = 36) and adjacent (n = 82) normal mucosa, primary tumor (n = 125), biopsy specimens (n = 96), and lymph node metastasis (n = 30) from rectal cancer patients participating in a clinical trial of preoperative RT.

RESULTS

Phosphatase of regenerating liver expression was increased from the distant to adjacent mucosa and to the primary tumor (p < 0.05). PRL was highly expressed at the invasive margin in 28% of the primary tumors and 26% of the metastases. In the RT group, strong PRL expression at the invasive margin was related to distant recurrence (p = 0.006) and poor survival (p = 0.01), but not in the non-RT group. The survival significance remained even after adjusting for Dukes' stage and differentiation (p = 0.02). Additional multivariate analyses showed that the correlation with prognostic significance of PRL differed between the RT and non-RT groups (p = 0.01).

CONCLUSION

Phosphatase of regenerating liver expression (rather than PRL-3 alone) at the invasive margin predicted resistance to RT and unfavorable survival in rectal cancer patients with preoperative RT.

Multiple displacement amplification of isolated DNA from human gallstones: molecular identification of Helicobacter DNA by means of 16S rDNA-based pyrosequencing analysis

BACKGROUND

Molecular typing of Helicobacter spp. in clinical biopsy specimens has become increasingly important. By means of nested polymerase chain reaction (PCR) amplification and Southern blot analysis of the PCR amplicons, we have shown that Helicobacter spp. DNA is present in human gallstones. In this study we have investigated the possibility of using multiple displacement amplification (MDA) of isolated gallstone DNA and pyrosequencing analysis for the molecular identification of Helicobacter spp.

MATERIALS AND METHODS

DNA isolated from the nucleus of 33 human gallstones and one control strain were used in a MDA assay. Subsequently, pyrosequencing analysis was performed either directly on MDA-DNA using primers flanking the Helicobacter spp. 16S rDNA variable V3 region or on PCR amplicons derived from broad-range primers flanking the 16S rDNA variable V3, V4, and V9 regions.

RESULTS

Pyrosequencing analysis of 16S rDNA derived from MDA-DNA revealed that Helicobacter spp.-like DNA was present in 25 of 33 (approximately 76%) gallstones. Using an H. pylori-specific Southern blot analysis, Helicobacter spp.-like DNA was present in 20 of 33 [approximately 61%] of the gallstones. Using MDA-DNA directly in pyrosequencing analysis, Helicobacter spp.-like DNA was present in 13 of 33 [approximately 39%] gallstones.

CONCLUSIONS

We conclude that multiple displacement amplification combined with pyrosequencing enables a rapid and accurate molecular typing of Helicobacter spp. from small and precious biopsy specimens.

Highly selective inhibition of inducible nitric oxide synthase ameliorates experimental acute pancreatitis

OBJECTIVES

Inducible nitric oxide synthase (iNOS) activity is increased in experimental acute pancreatitis. The aim of this study was to evaluate treatment with the selective iNOS inhibitors AR-C (AR-C102222AA) and L-NIL (L-N6-(1-iminoethyl)-lysine) in experimental acute pancreatitis.

METHODS

Acute pancreatitis was induced in anesthetized Australian possums by topical administration of carbachol on the sphincter of Oddi. AR-C treatment was 2 intravenous infusions (2.5 micromol/kg over 15 minutes) at 2 and 4 hours after acute pancreatitis induction. L-NIL treatment was an intraarterial infusion (1 mg/kg/h) from 2 hours after acute pancreatitis induction. At 8 hours, pancreatic tissue was harvested and inflammation assessed (histologic score). Blood samples were collected for plasma amylase, lipase, and amino acid levels. Blood pressure, central venous pressure, supplementary fluids, and urine output were monitored.

RESULTS

Treatment with AR-C or L-NIL reduced the plasma levels of amylase and the volume of supplementary fluids and improved the histological score (all P < 0.05). In animals with acute pancreatitis, plasma arginine levels were reduced (P < 0.05), while citrulline and ornithine levels increased (P < 0.05), consistent with increased nitric oxide production. Treatment with AR-C ameliorated the reduced arginine level.

CONCLUSIONS

Treatment with AR-C or L-NIL, commencing 2 hours after the induction of acute pancreatitis, has significant and beneficial effects in experimental acute pancreatitis in Australian possums.

The Influence of a load of L-arginine on serum amino acids and pancreatic apoptosis/proliferation and ATP levels in the rat

OBJECTIVES

Administration of high doses of amino acids like ethionine, methionine, and arginine causes pancreatic tissue damage. The initial mechanism behind these effects is not known. The aim of this study was to show the early effects of a load of L-arginine on programed cell death/proliferation and ATP levels in the pancreas.

METHODS

We analyzed in rats the effects of intraperitoneal administration of L-arginine on serum amino acids, pancreatic cell apoptosis/proliferation, and ATP levels at 8, 16, and 24 hours. Serum amino acid concentrations were measured with HPLC, tissue ATP was measured fluorometrically, apoptosis was studied with caspase-3 activity and histone-associated DNA-fragments, and proliferation was studied with thymidine autoradiography.

RESULTS

After a load of l-arginine, there were initially increased serum levels of L-arginine and L-citrulline, but these fell below control levels after 24 hours as well as amino acids in the glutamate family (ornithine, proline, histidine, and glutamine). Initially, increased ATP levels in the pancreatic tissue returned to control levels at 24 hours. The acinar cells proliferation was suppressed and the apoptosis rate strongly increased at 16 and 24 hours. Pancreatic histology showed vacuole formation in the acinar cells at 8 hours. At 16 hours, there was less vacuolization, but apoptotic bodies were seen, and at 24 hours there was cell degeneration but no necrosis.

CONCLUSIONS

After a load of l-arginine, amino acid metabolism causes a high ATP production in the pancreatic tissue that may cause mitochondrial initiation of cell death.

Cholecystokinin-8-Induced Hypoplasia of the Rat Pancreas: Influence of Nitric Oxide on Cell Proliferation and Programmed Cell Death

The background of cholecystokinin-8 (CCK-8)-induced hypoplasia in the pancreas is not known. In order to increase our understanding we studied the roles of nitric oxide and NF-kappaB in rats. CCK-8 was injected for 4 days, in a mode known to cause hypoplasia, and the nitric oxide formation was either decreased by means of N(omega)-nitro-L-arginine (L-NNA) or increased by S-nitroso-N-acetylpencillamine (SNAP). The activation of NF-kappaB was quantified by ELISA detection, apoptosis with caspase-3 and histone-associated DNA-fragmentation and mitotic activity in the acinar, centroacinar and ductal cells were visualized by the incorporation of [(3)H]-thymidine. Pancreatic histology and weight as well as protein- and DNA contents were also studied. Intermittent CCK injections reduced pancreatic weight, protein and DNA contents and increased apoptosis, acinar cell proliferation and nuclear factor kappaB (NF-kappaB) activation. It also caused vacuolisation of acinar cells. The inhibition of endogenous nitric oxide formation by L-NNA further increased apoptosis and NF-kappaB activation but blocked the increased proliferation and vacuolisation of acinar cells. The DNA content was not further reduced. SNAP given together with CCK-8 increased apoptosis and other pathways of cell death, raised proliferation of acinar cells and strongly reduced the DNA content in the pancreas. Histological examination showed no inflammation in any group. We conclude that during CCK-8-induced pancreatic hypoplasia, endogenously formed nitric oxide suppresses apoptosis but increases cell death along non-apoptotic pathways and stimulates regeneration of acinar cells. Exogenous nitric oxide enhances the acinar cell turnover by increasing both apoptotic and non-apoptotic cell death and cell renewal. In this situation NF-kappaB activation seems not to inhibit apoptosis nor promote cell proliferation.

Highly selective iNOS inhibition and sphincter of Oddi motility in the Australian possum

AIM

Inducible nitric oxide synthase (iNOS) plays a major role in acute pancreatitis. Selective inhibitors of iNOS are being developed as therapeutic agents. Sphincter of Oddi (SO) dysfunction may cause pancreatitis and nitric oxide is necessary for SO relaxation. A new highly selective iNOS inhibitor, AR-C102222AA (AR-C), is evaluated together with the established iNOS inhibitor, L-N(6)-(1-iminoethyl)lysine (L-NIL), and the selective neuronal nitric oxide synthase (nNOS) blocker S-methyl-l-thiocitrulline (SMTC).

METHODS

In anaesthetized Australian Brush-tailed possums, the effect of topical, i.v. or i.a. administration of these drugs was evaluated on spontaneous SO motility, blood pressure (BP) and pancreatic vascular perfusion. SO motility was recorded by manometry and pancreatic vascular perfusion by laser Doppler fluxmetry. Also, the effect of SMTC and AR-C on electrical field stimulation (EFS)-induced non-cholinergic non-adrenergic (NANC) SO relaxation in vitro was evaluated.

RESULTS

Infusion of AR-C (0.1-30 micromol kg(-1)) increased SO contraction frequency (P = 0.026) only at the two highest doses. L-NIL infusion (0.15 to 14.7 micromol kg(-1)) also increased SO contraction frequency at 8.8 micromol kg(-1) (P < 0.05) and reduced SO contraction amplitude at the two highest doses (P < 0.05). SMTC injections (0.5 nmol-2.4 micromol) produced a dose-dependent increase in SO contraction frequency (P = 0.009), but no effect was seen on the other parameters. In vitro SMTC (40-400 microm) inhibited EFS-induced NANC relaxation in a dose-dependent manner (P < 0.0005). In contrast AR-C (10-500 microm) had no effect on EFS-induced NANC relaxation (P > 0.05).

CONCLUSIONS

At low doses, AR-C does not effect SO motility or EFS-induced NO mediated relaxation. However, high doses of AR-C and L-NIL in vivo influenced SO motility by inhibiting nNOS activity and these effects need be considered in relation to therapeutic doses of this agent.

The bile acid independent flow is reduced in the transplanted liver

Bile secretion is an important indicator of liver graft function. Reports on bile formation by the transplanted liver with stable function some months after operation are scarce. In this study bile flow, bile salt secretion rate (BSSR) and biliary clearance of polyethylene glycol (PEG) 900, a marker of canalicular bile flow, were studied in a group of liver-transplanted (LTX) patients (n = 8) 3-6 months after transplantation. A group of cholecystectomized patients with indwelling T-tubes (n = 6) served as a control group. Both groups were treated with oral ursodeoxycholic acid (500 mg/day). On the day of the study bile was drained for 6 h by gravity and four-hourly samples were used in the calculations. The relation between bile flow and BSSR analysed with linear regression showed a reduced bile acid independent flow in the liver-transplanted group (0.11 ml/min) compared with the control group (0.20 ml/min). The relation between biliary clearance of PEG 900 and BSSR showed a significantly steeper slope for the cholecystectomized control patients (1.40 ml/micromol) compared with the liver-transplanted patients (0.30 ml/micromol). We conclude, that in spite of stable graft function with normal liver enzmyes, the transplanted liver has a reduced bile acid independent bile flow. The transplanted liver also has a reduced biliary clearance of PEG 900 indicating a reduced canalicular bile flow. The cause of this impaired bile formation could be due to the influence of the immunosuppressive drug cyclosporin, the result of damage to the liver during preservation and reperfusion or the continuous immunological challenge to the graft.

Depletion of serum L-arginine in patients with acute pancreatitis

INTRODUCTION

Acute pancreatitis may be initiated by interference with the pancreatic outflow to the duodenum. This flow is normally regulated by reflex relaxation of the sphincter of Oddi in which nitric oxide is an important mediator.

AIM

To test the hypothesis that acute pancreatitis involves a depletion in serum L-arginine resulting in impaired production of nitric oxide.

METHODS

We measured serum L-arginine and L-citrulline and urinary nitrite/nitrate concentrations 1 to 3 days after the onset of symptoms in 11 patients with gallstone pancreatitis, 10 patients with alcoholic pancreatitis, and 6 patients with idiopathic pancreatitis. We compared their results with those from control groups of 13 healthy blood donors, 9 patients fasting before hernia operations, 8 patients with acute cholecystitis, and 9 alcoholic subjects but no pancreatitis. Serum arginine and citrulline concentrations were measured with high performance liquid chromatography, and urinary nitrite/nitrate spectrophotometrically.

RESULTS

Patients with acute pancreatitis, of whatever cause, had lower serum L-arginine and L-citrulline concentrations than controls. Patients with gallstone and idiopathic pancreatitis also have reduced urinary concentrations of nitrite and nitrate but this was not seen in patients with alcoholic pancreatitis.

CONCLUSIONS

L-arginine and L-citrulline concentrations are depleted in the serum of patients with acute pancreatitis. Reduced urinary nitrite and nitrate in gallstone pancreatitis indicate that there is a defect formation of nitric oxide. This may cause a functional obstruction of the outflow of pancreatic juice to the duodenum and so may be involved in the pathophysiology of acute pancreatitis.

The influence of nitric oxide on basal and cholecystokinin-8-induced proliferation and apoptosis in the rat pancreas

Nitric oxide (NO) is formed by different cell types in the pancreas. In this study, inhibition of endogenous nitric oxide by N(omega)-nitro-L-arginine (L-NNA) reduced the urinary excretion of NO(2)/NO(3) and raised serum L-arginine and the NO donator S-nitroso-N-acetylpenicillamine (SNAP) increased the urinary excretion of NO(2)/NO(3). The peptide cholecystokinin-8 (CCK-8) has a strong influence on exocrine pancreatic proliferation. Rat pancreas was excised and studied with regard to tissue weight, protein and DNA contents after 3 days of treatment with saline, L-NNA or SNAP given separately or combined with CCK-8. Further, proliferation of different pancreatic cells was studied with [3H]-thymidine incorporation and apoptotic activity was studied by analysing caspase-3 activity and histone-associated DNA fragments. The effects of L-NNA indicate that endogenous nitric oxide formation has a tonic inhibition on apoptosis in the pancreas during both basal condition and growth stimulation by CCK-8. In CCK-induced hyperplasia, NO inhibits the proliferation of acinar cells but stimulates ductal cells. Endogenous NO may regulate the balance between proliferation and apoptosis and in a situation of growth stimulation by CCK-8, it has a tonic inhibition on both mitogenesis and apoptosis thus slowing down the acinar cell turnover in the pancreas.

[Guidelines for management of patients with pancreatic cancer]

The incidence of pancreatic cancer has fallen during the last ten years in Sweden. Early signs and symptoms of the disease are still undiscovered and when diagnosis is made the disease is incurable in most patients. Transabdominal ultrasonography is the first-line imaging test followed by spiral computed tomography (CT) and magnetic resonance imaging (MRI) if required for definite diagnosis. Spiral CT is also the imaging test of choice for assessment of resectability of the tumor. Surgical removal of the tumor is the only chance of cure. Markedly improved hospital mortality after pancreaticoduodenectomy is reported and an association between hospital volume and outcome of the operation has been established. Longterm survival after attempted curative resection continues to be dismal, however. Adjuvant treatment should not be given outside clinical studies. Palliative treatment has improved thanks to progress in the field of endoscopy, interventional radiology and in management of pain and nutrition. Palliative chemotherapy should only be given selectively outside clinical studies. Radiotherapy has no proven effects on survival. Special pancreatic cancer treatment teams with catchment areas of 2-4 million inhabitants are recommended by international authorities.

Hydatid disease of the spine: case report

A rare case of spinal hydatid disease presenting with paraparesis and sensory loss is reported. The patient was treated with albendazole resulting in significant improvement within eight weeks. Investigations and treatment modalities are discussed.

Acetazolamide inhibits stimulated feline liver and gallbladder bicarbonate secretion

Bile acidification is a key factor in preventing calcium carbonate precipitation and gallstone formation. Carbonic anhydrase II (CA II), that is inhibited by acetazolamide, plays a role in regulation of the acid-base balance in many tissues. This study examines the effect of acetazolamide on secretin- and vasoactive intestinal peptide (VIP)-stimulated gallbladder mucosal bicarbonate and acid secretion. Gallbladders in anaesthetized cats were perfused with a bicarbonate buffer bubbled with CO2 in air. In 20 experiments VIP (10 microg kg(-1) h(-1)) and in 10 experiments secretin (4 microg kg(-1) h(-1)) were infused continuously intravenous (i.v.). Hepatic bile and samples from the buffer before and after perfusion of the gallbladder were collected for calculation of ion and fluid transport. During basal conditions a continuous secretion of H+ by the gallbladder mucosa was seen. Intravenous infusion of vasoactive intestinal peptide (VIP) and secretin caused a secretion of bicarbonate from the gallbladder mucosa (P < 0.01). This secretion was reduced by intraluminal (i.l.) acetazolamide (P < 0.01). Bile flow was enhanced by infusion of VIP and secretin (P < 0.01) but this stimulated outflow was not affected by i.v. acetazolamide. The presence of CA II in the gallbladder was demonstrated by immunoblotting. Biliary CA activity has an important function in the regulation of VIP- and secretin-stimulated bicarbonate secretion across the gallbladder mucosa.

Identification of Helicobacter pylori DNA in human cholesterol gallstones

BACKGROUND

The gallbladder mucosa secretes hydrogen ions and is covered by mucus. The environmental conditions for bacterial colonization are similar to those in the stomach. Gallbladder stones often contain DNA from enteric bacteria, but no compelling evidence demonstrates that Helicobacter spp. have been present. The aim of this study was to establish bacterial DNA profiles in cholesterol gallstones with special reference to Helicobacter pylori.

METHODS

Cholesterol gallstones from 20 patients were subjected to polymerase chain reaction, bacterial profiling by temporal temperature gradient gel electrophoresis, automated DNA sequencing, and Southern blot analysis using a Helicobacter sp. specific primer. A nested ureI-PCR assay was used to discriminate between gastric and non-gastric H. pylori.

RESULTS

TTGE, partial 16S rDNA sequencing, and hybridization analysis revealed the presence of DNA presumably representing a mixed bacterial flora in cholesterol gallstones, including H. pylori in the gallstone centres in 11 out of 20 patients. In three cases, the urel-PCR assay revealed non-gastric H. pylori.

CONCLUSIONS

These data support the presence of DNA from a mixed bacterial population, including H. pylori in cholesterol gallstones, reflecting either that H. pylori is an indigenous part of a flora in the stone-containing gallbladder or, alternatively, that H. pylori colonization in the biliary tract predisposes to cholesterol gallstone formation.

[The incidence of gallbladder cancer in Sweden has decreased. The poor prognosis can possibly be improved by radical surgery]

Gallbladder cancer is a rare disease with poor prognosis and short survival time. The condition is usually associated with gallstones and predominantly affects women. We have taken data from the National Cancer Register and the Cause of Death Register in Sweden and studied the annual incidence of and mortality due to gallbladder cancer from 1988 to 1997. Incidence has declined during this period, which may be explained by a high rate of cholecystectomies in Sweden between 1950 and 1970. Prognosis has traditionally been poor, with a median survival time of 3.5 months, which might be explained by the fact that the disease usually is diagnosed at an advanced stage. Epidemiological figures show that prognosis may have improved during the past decade. In several retrospective studies, mainly from Japan, better results with longer survival times are reported after extended surgery. In a small group of 11 patients with gallbladder cancer, Nevin grade II-V, who underwent extended surgery at The University Hospital in Linköping, there are no signs of recurrent disease in 10 patients after a follow-up of 1-8 years.

Cholecystokinin octapeptide induces both proliferation and apoptosis in the rat pancreas

Cholecystokinin-8 (CCK-8) causes exocrine pancreatic hypertrophy and hyperplasia. High doses of the CCK analogue cerulein causes necrosis and an inflammatory response in the pancreas. We have studied the pancreatic growth response in rats after administration of CCK-8 for 3 days, given either intermittently (20-80 microg/kg) twice a day, or continuously (2.4-48 microg/kg per 24 h). Plasma CCK-8 levels, pancreatic wet weight, water, protein and DNA contents and the pancreatic caspase-3 activity were measured. Cell proliferation was visualized by [3H]thymidine incorporation and apoptosis by TUNEL reaction. Continuous administration of CCK-8 dose-dependently increased the plasma CCK levels, the pancreatic wet weight, protein and DNA contents as well as thymidine labeling index, apoptotic index and caspase-3 activity. Intermittent injections of CCK-8 caused transient raises in plasma CCK, increased apoptotic index and caspase-3 activity, a dose-dependent increase in thymidine labeling but caused a dose-dependent reduction of pancreatic wet weight, protein, and DNA contents. It is concluded that CCK-8 causes both increased proliferation and apoptosis in the pancreas. In case of continuous administration of CCK-8, the proliferation outweighs the apoptosis causing hyperplasia but in the case of intermittent administration the opposite effect is seen.

Results of laparoscopic compared with open cholecystectomy

Laparoscopic cholecystectomy was introduced in 1985 and diffused within a few years throughout the world. The avalanche-like spread resulted in this procedure not being scientifically supported by results of controlled clinical trials. By 1997 there were just 13 randomised controlled trials and 150 prospective studies that followed a research protocol, while there were more than 1500 retrospective analyses of series of operations in a country, in a specific hospital, or by a specific surgeon. Comparisons with the conventional laparotomy technique and with minilaparotomy techniques are complicated by the fact that the variables compared, such as operation times, complication rates, and costs, varied over time.

Laparoscopic cholecystectomy for acute cholecystitis

Acute cholecystitis was initially considered a contra-indication for laparoscopic cholecystectomy, but today the laparoscopic route is generally used even for severe acute cholecystitis. Several studies have shown that this is possible, although the conversion and complication rates are high, but there are no randomised controlled trials that evaluate the complications and costs of this technique compared with conventional open techniques. The timing of a laparoscopic cholecystectomy for acute cholecystitis is also a matter of debate as well as its use in elderly patients with this condition.

[Guidelines for management of patients with acute pancreatitis]

During recent years new concepts and methods have been introduced in the management of acute pancreatitis. Severity and risk of complications show wide variation. Outcome is also dependent on the physician's experience and on his local resources. In this light the Swedish Society of Upper Abdominal Surgery has elaborated national guidelines for management. Attention is paid to diagnosis, severity assessment and etiology. Furthermore, guidelines are offered for treatment of mild and severe pancreatitis, as well as for the management of pseudocysts. The role of multidisciplinary intensive care specialist teams in the management of severe disease is emphasized. The guidelines are supported by the Swedish Society of Gastroenterology, the Swedish Society of Gastroenterology, the Swedish Society of Anesthesiology and Intensive Care and by experts from other Nordic countries.

Role of cyclooxygenase-2 for fluid secretion by the inflamed gallbladder mucosa

Inflammatory fluid secretion by the gallbladder mucosa in experimental cholecystitis is induced by activation of cyclooxygenase, which leads to an increase in prostaglandin formation. Cyclooxygenase exists as a constitutive (cyclooxygenase-l) and an inducible (cyclooxygenase-2) isoform. The aim of this study was to demonstrate the role of cyclooxygenase-2 in inflammatory fluid secretion of the feline gallbladder. Experiments were performed 10 weeks after a surgical procedure in which chronic cholecystitis was induced in cats by ligation of the cystic duct and implantation of a gallstone in the gallbladder. Gallbladder fluid transport was continuously monitored via a perfusion system. In inflammed gallbladders the continuous fluid secretion was reversed to absorption by intravenous injection of the selective cyclooxygenase-2 blocker, NS 398 (P <0.001). Increased levels of the inducible cyclooxygenase-2 were shown by immunoblotting in inflamed gallbladders. Selective pharmacologic blockage of cyclooxygenase-2 reduced the prostaglandin E2 release to the inflamed gallbladder lumen (P <0.01). These data suggest that cyclooxygenase-2 is involved in the inflammatory response during chronic cholecystitis. Selective cyclooxygenase-2 blockers may offer an alternative to traditional nonsterodial anti-inflammatory drugs with fewer side effects in patients with cholecystitis who are awaiting operation.

Human gallbladder mucosal function: effects on intraluminal fluid and lipid composition in health and disease

Gallbladder mucosal absorption of fluid during fasting is a well-known process. Indirect in vivo and recent in vitro evidence for physiologically relevant gallbladder absorption of cholesterol and phospholipids from bile has been observed in humans. The present study explored and compared by indirect means the relative efficiences of human gallbladder mucosal absorption of fluid and lipids in health and disease. Biliary lipids and pigment content were measured in fasting gallbladder bile samples obtained from gallstone-free controls and from four study groups: multiple and solitary cholesterol gallstone patients, and morbidly obese subjects with and without gallstones. Bile salts and pigment content were significantly greater in gallstone-free controls than in all other disease study groups. This was interpreted as evidence of more effective gallbladder mucosal fluid absorption in nonobese gallstone-free controls compared to that in all other groups. Correlation plot analyses of biliary lipids showed lower concentrations of phospholipids than expected from the index bile salt concentrations. The same was found for cholesterol concentrations but only in supersaturated samples. These findings were much more pronounced in gallstone free-controls and were accordingly interpreted as evidence of more efficient gallbladder absorption of both phospholipids and cholesterol in controls compared with that found in each of the disease study groups. Moreover, impaired gallbladder mucosal function, while invariably associated with cholesterol gallstone disease, was not found to be a necessary consequence of the physical presence of stones. It is concluded that efficient gallbladder mucosal absorption of both fluid and apolar lipids from bile is a normal physiological process that is often seriously impaired in the presence of either cholesterol gallstone disease or at least one of its precursor forms.

Variations in pigment and carbohydrate content of gallbladder bile affect accurate quantitation of total protein when using the fluorescamine method

BACKGROUND

Despite solute dilution and reduced total lipid concentrations, an unexplained increase in protein concentration has been reported to occur in the gallbladder bile of cholesterol gallstone patients.

METHODS

Solutes in gallbladder bile from gallstone-free controls and from four study groups were measured using standard methods. Total proteins were measured using amino acid analysis and a conventional fluorescamine method.

RESULTS

Bile salts and pigment content were greater in gallstone-free controls than in all other study groups, including morbidly obese gallstone-free subjects. Total biliary protein concentration, as determined by amino acid analysis in the gallstone-free control group was higher than in non-obese gallstone patients with multiple stones and in morbidly obese gallstone-free subjects. Total biliary proteins as measured with fluorescamine, however, did not show intergroup differences. A major problem of the conventional fluorescamine assay is shown to be an artefact arising from the high pigment content of the more concentrated samples.

CONCLUSIONS

Very dilute gallbladder bile samples are often found in the presence of gallstone disease. This also occurs in morbidly obese subjects, even in the absence of gallstones. Although the contribution of protein secretion/absorption by the gallbladder can also be relevant, especially in the presence of morbid obesity, the protein concentration in gallbladder bile, when accurately measured, generally parallels the concentrations of non-absorbed biliary solutes, reflecting the efficiency of fluid absorption. Measurement of biliary proteins by the conventional fluorescamine method is unreliable in clinical studies in which intergroup differences in pigment content are commonly present.