David R. Fine

Expression of Transforming Growth Factor-β1 by Pancreatic Stellate Cells and Its Implications for Matrix Secretion and Turnover in Chronic Pancreatitis

Pancreatic stellate cells mediate fibrosis in chronic pancreatitis. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs)-1 and -2 are crucial modulators of fibrosis. Transforming growth factor-beta (TGF-beta) is a key regulator of extracellular matrix production and myofibroblast proliferation. We have examined MMP and TIMP synthesis by transformed cultured pancreatic stellate cells and their regulation by TGF-beta 1. By Northern analysis they expressed mRNAs for procollagen 1, TIMP-1, TIMP-2, and MMP-2. Expression of membrane type-1 MMP was confirmed by Western blotting. By immunohistochemistry these enzymes localized to fibrotic areas in human chronic pancreatitis. Active TGF-beta 1 constitutes 2 to 5% of total TGF-beta 1 secreted by pancreatic stellate cells; they express TGF-beta receptors I and II. Exogenous TGF-beta 1 (10 ng/ml) significantly increased procollagen-1 mRNA by 69% and collagen protein synthesis by 34%. Similarly TGF-beta 1 at 0.1, 1, and 10 ng/ml significantly reduced cellular proliferation rate by 37%, 44%, and 44%, respectively, whereas pan-TGF-beta-neutralizing antibody increased proliferation by 40%. TGF-beta1 (10 ng/ml) down-regulated MMP-9 by 54% and MMP-3 by 34% whereas TGF-beta 1-neutralizing antibody increased MMP-9 expression by 39%. Pancreatic stellate cells express both mediators of matrix remodeling and the regulatory cytokine TGF-beta 1 that, by autocrine inhibition of MMP-3 and MMP-9, may enhance fibrogenesis by reducing collagen degradation.

Type I Collagen Promotes the Malignant Phenotype of Pancreatic Ductal Adenocarcinoma

Purpose: The purpose of this study was to determine the role of functional interactions between pancreatic cancer cells and pancreatic stellate cells (PSCs) in the formation of the desmoplastic reaction (DR) in pancreatic cancer and to characterize the effect of type I collagen (the predominant component of the DR) on pancreatic cancer cell phenotype. Experimental Design: PSCs and type I collagen were identified in sections of pancreatic cancer using immunohistochemistry, and their anatomic relationship was studied. Interactions among pancreatic cancer cell lines (MIA PaCa-2, Panc-1, and AsPC-1), primary cultures of human PSCs, and type I collagen were investigated in a series of tissue culture models. Results: In vivo, the DR causes gross distortion of normal pancreas, bringing cancer cells into close contact with numerous PSCs and abundant type I collagen. In tissue culture models of pancreatic cancer, conditioned media from each cell line increased PSC [3H]thymidine incorporation up to 6.3-fold that of controls, and AsPC-1 cells also increased PSC collagen synthesis 1.3-fold. Type I collagen was observed to increase long-term survival of pancreatic cancer cells treated with 5-fluorouracil, by up to 62% in clonogenic assays. This was because type I collagen increased the proliferation of cancer cells ([3H]thymidine incorporation was up to 2.8-fold that of cells cultured on tissue culture plastic) and reduced apoptosis of AsPC-1 cells in response to 5-fluorouracil (by regulating mcl-1). Conclusions: These experiments elucidate a mechanism by which the DR in pancreatic cancer may form and, via the collagen within it, promote the malignant phenotype of pancreatic cancer cells, suggesting significant detriment to the host.

Hepatic Stellate Cells Express the Low Affinity Nerve Growth Factor Receptor p75 and Undergo Apoptosis in Response to Nerve Growth Factor Stimulation

We have examined the expression of p75, a member of the TNF receptor superfamily in hepatic stellate cells (HSC) and pancreatic stellate cells (PSC). Activated HSC and PSC were demonstrated by Western blot analysis to express p75. p75 was immunolocalized to cells with a myofibroblast-like morphology in the fibrotic bands of six fibrotic and cirrhotic liver biopsies and three biopsies of fibrotic human pancreas. Immunostaining of parallel sections indicated that these cells were alpha-smooth muscle actin-positive, identifying them as activated HSC and PSC, respectively. HSC apoptosis in tissue culture in the presence of serum was quantified after addition of 0.1 to 100 ng/ml of nerve growth factor (NGF) a ligand for p75, by in situ counting of apoptotic bodies after addition of acridine orange. HSC demonstrated a significant increase in apoptosis in response to 100 ng/ml NGF (0.05 > P by Wilcoxons rank; n = 7) after 24 hours. NGF 100 ng/ml had no effect on HSC proliferation, but reduced total HSC DNA by 19% relative to control after 24 hours (n = 3). These data demonstrate that activated HSC express p75 and respond to NGF stimulation by undergoing apoptosis. We therefore report p75 as a novel marker of activated HSC and suggest that signaling via ligand binding to p75 may provide a mechanism for selective apoptosis of HSC.

The epidemiology and socioeconomic impact of chronic pancreatitis

Epidemiological studies have been published worldwide in recent decades describing the incidence, mortality, aetiology and trends of chronic pancreatitis. Accumulated evidence suggests that chronic pancreatitis is increasing in incidence and hospital admission rates are rising accordingly. Alcoholic chronic pancreatitis was previously more common in the developed world than elsewhere, but is now increasing worldwide due to growing per capita alcohol consumption in each nation. Supporting alcohol and smoking cessation in individual patients is essential to slow disease progression and improve overall health, as most patients will die of cirrhosis, cardiovascular disease or smoking related cancers rather than chronic pancreatitis. The socioeconomic impact of chronic pancreatitis is difficult to quantify as little data exists, however given the rising incidence the costs to health care and society are likely to increase. This chapter will describe the epidemiology and aetiology of chronic pancreatitis worldwide and discusses the factors that influence its socioeconomic impact.

Colonic expression of leukotriene-pathway enzymes in inflammatory bowel diseases

Background Leukotrienes derived from the 5‐lipoxygenase pathway are proinflammatory lipid mediators that possibly play a role in inflammatory bowel diseases. The expression of 5‐lipoxygenase pathway proteins has not previously been examined in colonic mucosa in inflammatory bowel disease. Results Quantitative immunohistochemical analyses showed that, compared to those of the control subjects (n = 9), colonic biopsies from patients with active inflammatory bowel disease (n = 17) had 3‐ to 7‐fold higher mean counts of cells expressing 5‐lipoxygenase (P = 0.03), 5‐lipoxygenase‐activating protein (P = 0.005), and the leukotriene A4 hydrolase (P = 0.004), which make up the biosynthetic pathway of the potent neutrophil chemotaxin leukotriene B4. Immunoexpression of the leukotriene C4 synthase was unaltered (P > 0.2). The increased representation of leukotriene B4–pathway enzymes was associated with higher counts of neutrophils (P = 0.0001), macrophages (P = 0.03), eosinophils (P = 0.0004), CD8+ T cells (P < 0.001), activated T cells (P < 0.05), and B cells (P < 0.05) but not of mast cells (P > 0.9). These eicosanoid and cellular changes were most marked in the subgroup of patients with ulcerative colitis (n = 9), and were absent in patients with quiescent disease (n = 6). The anomalies in the 5‐lipoxygenase pathway were accompanied as expected by more cells immunostaining for cytokine‐inducible COX‐2 (P = 0.004, n = 17), but this study also revealed a greater number of cells expressing COX‐1 in the samples from the patients in the ulcerative colitis subgroup (P = 0.03, n = 9). Conclusions The 5‐lipoxygenase data provide a cellular basis for increased tissue synthesis of the leukotriene B4, as reflected in the colonic mucosa and rectal dialysates of patients with active inflammatory bowel disease, which contributes to neutrophil influx and colonic injury. The COX‐1/COX‐2 data highlight the ambiguous functional role of prostanoid pathways in inflammatory bowel diseases. (Inflamm Bowel Dis 2007)

Apoptosis and proliferation of acinar and islet cells in chronic pancreatitis: evidence for differential cell loss mediating preservation of islet function

Background: Chronic pancreatitis is characterised clinically by early exocrine insufficiency, with diabetes mellitus occurring as a late phenomenon. This is mirrored pathologically by extensive acinar cell destruction and islet preservation. The mechanisms underlying this differential rate of cellular destruction are unknown. Aims: To test the hypothesis that acinar loss and islet preservation in chronic pancreatitis occurs due to differential epithelial kinetics and investigate the role of inflammatory cells and cell cycle associated molecules. Methods: Archival tissue from six chronic pancreatitis cases was compared with six normal controls using TUNEL and immunohistochemistry for CD3, CD20, CD68, MIB-1, Bcl-2, Bax, Fas, Fas ligand, retinoblastoma protein (Rb), and tissue inhibitor of metalloproteinases 1 (TIMP-1) and 2 (TIMP-2). Results: The acinar cell apoptotic index (AI) and proliferation index were higher in chronic pancreatitis than controls. T lymphocytes diffusely infiltrated fibrous bands and acini but rarely islets. Acinar Bcl-2 expression exceeded islet expression in chronic pancreatitis and controls while Bax was strongly expressed by a subset of islet cells and weakly by centroacinar cells. Islet Fas and Fas ligand expression exceeded acinar expression in chronic pancreatitis and controls. Acinar Rb expression was higher in chronic pancreatitis than in controls. Islets in chronic pancreatitis and controls showed intense TIMP-1 and TIMP-2 expression. Conclusion: Apoptosis plays a significant role in acinar loss in chronic pancreatitis. Acinar Bcl-2 and islet Bax expression indicates complex AI control. Increased acinar Rb expression in chronic pancreatitis may differentially promote acinar loss. Fas ligand expression may be restricted to islet cell membranes through TIMP-1 expression and inhibit islet damage by promoting apoptosis of cytotoxic T lymphocytes.

Tumor-stromal interactions in pancreatic cancer

Pancreatic adenocarcinoma has one of the worse prognoses of any cancer with a 5-year survival of only 3%. Pancreatic cancer displays one of the most prominent stromal reactions of all tumors and it is evident that this is a key contributing factor to disease outcome. The tumor microenvironment of pancreatic cancer harbors a wide spectrum of cell types and a complex network of mechanisms which all serve to promote tumor progression. It is clear that the symbiotic relationship between pancreatic cancer cells and stellate cells is the chief factor creating this unique tumor milieu. Pancreatic stellate cells play critical roles in evasion of cancer cell apoptosis, invasion and metastases, angiogenesis, and promotion of an immunosuppressive environment, all key hallmarks of malignancy. Existing treatments for pancreatic cancer focus on targeting the cancer cells rather than the whole tumor, of which cancer cells represent a small proportion. It is now increasingly evident that research targeted towards the interactions between these cell types, ideally at an early stage of tumor development, is imperative in order to propel the way forward to more effective treatments.

High-dose fish oil and antioxidants in Crohn's disease and the response of bone turnover: a randomised controlled trial.

Crohns disease is associated with altered bone turnover that may be influenced by nutritional status, the systemic inflammatory response, cytokine production by circulating (peripheral blood) mononuclear cells (PBMC) and antioxidant micronutrient intake. High-dose fish oil is associated with reductions in disease relapse and inflammatory markers, and modulates PBMC function. The effect of fish oil plus antioxidants on bone turnover and PBMC function (the production of interferon-gamma and prostaglandin E2) in Crohns disease was investigated in a randomised-controlled trial. Patients with currently or recently raised biochemical markers of inflammation (C-reactive protein > or = 6.9 mg/l or erythrocyte sedimentation rate > or =18 mm/h) received fish oil (providing 2.7 g/d EPA and DHA) and antioxidants (vitamins A, C and E, and Se) (n 31) or placebo (n 30) for 24 weeks. Bone turnover was assessed by measuring the concentrations of urinary deoxypyridinoline (bone resorption) and serum osteocalcin (bone formation). Fish oil plus antioxidants were associated with increases in EPA, DHA Se in plasma (all P < 0.01), and with a reduction in interferon-gamma production by mitogen-stimulated PBMC, which demonstrated a negative correlation with deoxypyridinoline/creatinine:osteocalcin ratio (r - 0.33, P = 0.009). There were no differences between the groups at 24 weeks in the response of deoxypyridinoline or osteocalcin or their ratio, or in nutritional status. Dietary supplementation in Crohns disease with high intakes of EPA and DHA, as fish oil, plus antioxidants was associated with a modulated production of interferon-gamma by PBMC but not altered indices of bone turnover.

Improving outpatient services: the Southampton IBD virtual clinic

The follow-up of inflammatory bowel disease (IBD) patients is challenging due to the relapsing remitting nature of the diseases, the wide spectrum of severity and complexity as well as the need for monitoring of long-term complications and drug treatments. Conventional outpatient follow-up lacks flexibility for patients and there are competing pressures for clinic time. Alternative follow-up pathways include telephone clinics, self-management programmes or discharging patients. The IBD virtual clinic (VC) is a further option. Patients with an established diagnosis for >2 years, who have been stable for >1 year, do not have primary sclerosing cholangitis and who give their consent, are entered into the VC system. Two months before their annual follow-up is due patients are sent blood test forms and a simple questionnaire with an information sheet. If they meet any of the criteria on the questionnaire, they are asked to contact the IBD specialist nursing team to discuss their situation. The blood test results and the patients database entry are reviewed to ensure that they are not due surveillance investigations. The patients and their GPs then receive a letter informing them of their management plan. We currently follow-up 20% of the Southampton IBD cohort using the VC. The VC system is an innovative, efficient and patient-responsive method for following up mild to moderate IBD. It is well liked by patients but is dependent on a well-maintained database with good integration of IT systems and requires both clerical and IBD nurse specialist support.

A life with prosopagnosia

The author gives an anecdotal account of his life with developmental prosopagnosia (DP). He was not formally diagnosed until the age of 53 and has evolved a complicated strategy for recognizing people based on non-facial physical features and context. He describes his experiences through infancy, school, university life and courtship, work and family life. He believes that he has lived a full and successful life despite DP but that some aspects of his social and work life were impaired by face-blindness. In his experience people react positively and helpfully if the consequences of DP are explained to them, and this improves social interactions and communications.