Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis

Background: Interactions between mononuclear cells and activated pancreatic myofibroblasts (pancreatic stellate cells; PSC) may contribute to inflammation and fibrosis in chronic pancreatitis (CP). Methods: Markers of fibrosis and inflammation were concomitantly analysed by immunohistochemistry in chronic pancreatitis tissues. In vitro, PSC were stimulated with TNFalpha and LPS. Primary human blood mononuclear cells (PBMC) and PSC were cocultured, followed by analysis of cytokines and extracellular matrix (ECM) proteins. PBMC were derived from healthy donors and CP and septic shock patients. Results: In areas of mononuclear cell infiltration in chronic pancreatitis tissues, there was decreased immunoreactivity for collagen1 and fibronectin, in contrast to areas with sparse mononuclear cells, although PSC were detectable in both areas. LPS and TNFalpha induced collagen1 and fibronectin levels as well as the matrix degradation enzyme MMP-1. Coculture experiments with PSC and PBMC revealed increased fibronectin secretion induced by PBMC. In addition, donor and CP PBMC significantly induced an increase in IL-6, MCP-1 and TGFbeta levels under coculture conditions. Determination of the source of cytokines and ECM proteins by mRNA expression analysis confirmed PSC as major contributors of ECM production. The increase in cytokine expression was PBMC- and also PSC-derived. Conclusion: Mononuclear cells modulate the activity of pancreatic stellate cells, which may in turn promote fibrosis and inflammation

Cancer-Stellate Cell Interactions Perpetuate the Hypoxia-Fibrosis Cycle in Pancreatic Ductal Adenocarcinoma1

Background and Aims Although both cancer and stellate cells (PSCs) secrete proangiogenic factors, pancreatic cancer is a scirrhous and hypoxic tumor. The impact of cancer-PSCs interactions on angiogenesis was analyzed. Methods Expression of periostin, CD31, and α-smooth muscle actin was assessed by immunohistochemistry. Human PSCs and cancer cells were cultivated under normoxia and hypoxia alone, or in coculture, to analyze the changes in their angiogenic and fibrogenic attributes, using enzyme-linked immunosorbent assay, immunoblot, and quantitative polymerase chain reaction analyses and growth of cultured endothelial cells in vitro. Results On the invasive front of the activated stroma, PSCs deposited a periostin-rich matrix around the capillaries in the periacinar spaces. Compared with the normal pancreas, there was a significant reduction in the microvessel density in chronic pancreatitis (five-fold, P < .001) and pancreatic cancer (four-fold, P < .01) tissues. In vitro, hypoxia increased PSCs' activity and doubled the secretion of periostin, type I collagen, fibronectin, and vascular endothelial growth factor (VEGF). Cancer cells induced VEGF secretion of PSCs (390 ± 60%, P < .001), whereas PSCs increased the endostatin production of cancer cells (210 ± 14%, P < .001) by matrix metalloproteinase-dependent cleavage. In vitro, PSCs increased the endothelial cell growth, whereas cancer cells alone, or their coculture with PSCs, suppressed it. Conclusions Although PSCs are the dominant producers of VEGF and increase endothelial cell growth in vitro, in the peritumoral stroma, they contribute to the fibrotic/hypoxic milieu through abnormal extracellular matrix deposition and by amplifying endostatin production of cancer cells

Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis-0

<p><b>Copyright information:</b></p><p>Taken from "Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis"</p><p>http://www.translational-medicine.com/content/5/1/63</p><p>Journal of Translational Medicine 2007;5():63-63.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2234395.</p><p></p>tin (B; VIM), CD31 (C), CD45 (D), collagen1 (E; COL) and fibronectin (F; FBN). Arrows: area around packed clusters of mononuclear cells. Arrowheads in A-C: pancreatic stellate cells (SMA- and VIM-positive, CD31-negative). Arrowhead in D: loosely distributed area of mononuclear cell infiltration. Arrowhead in E&F: areas of less intense immunoreactivities for collagen1 and fibronectin. Dotted arrows: Areas of strong collagen1 and fibronectin staining. Original magnification: ×50. (G) Arrows: areas of loosely distributed/single mononuclear cells, dotted arrows: area without mononuclear cells. (H&I) Arrows/dotted arrows: corresponding areas to (G)

Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis-3

<p><b>Copyright information:</b></p><p>Taken from "Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis"</p><p>http://www.translational-medicine.com/content/5/1/63</p><p>Journal of Translational Medicine 2007;5():63-63.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2234395.</p><p></p> White bars: Pooled donor, CP or sepsis PBMC and corresponding PSC supernatants. Black bars: coculture supernatants. *p < 0.05 as assessed using the Mann-Whitney U test. (B) Immunoblot analysis of fibronectin in PSC cell lysates. Densitometry shown as percent of control adjusted to the corresponding gamma-tubulin density

Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis-7

<p><b>Copyright information:</b></p><p>Taken from "Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis"</p><p>http://www.translational-medicine.com/content/5/1/63</p><p>Journal of Translational Medicine 2007;5():63-63.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2234395.</p><p></p>phaSMA- (SMA) and vimentin-positive (VIM) structures are endothelia, CD31 staining was performed. (D-F) In areas of loosely packed mononuclear cells (arrowhead in D) and packed mononuclear cells (white arrow in D), there is sparse immunoreactivity for collagen1 (arrowhead and white arrow in E) and moderate staining for fibronectin (arrowhead and white arrow in F). In areas with a low number of CD45-positive mononuclear cells (dotted arrow in D), the staining intensities for collagen1 (dotted arrow in E; COL) and fibronectin (dotted arrow in F; FBN) are stronger. Original magnification: ×200

Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis-6

<p><b>Copyright information:</b></p><p>Taken from "Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis"</p><p>http://www.translational-medicine.com/content/5/1/63</p><p>Journal of Translational Medicine 2007;5():63-63.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2234395.</p><p></p>tin (B; VIM), CD31 (C), CD45 (D), collagen1 (E; COL) and fibronectin (F; FBN). Arrows: area around packed clusters of mononuclear cells. Arrowheads in A-C: pancreatic stellate cells (SMA- and VIM-positive, CD31-negative). Arrowhead in D: loosely distributed area of mononuclear cell infiltration. Arrowhead in E&F: areas of less intense immunoreactivities for collagen1 and fibronectin. Dotted arrows: Areas of strong collagen1 and fibronectin staining. Original magnification: ×50. (G) Arrows: areas of loosely distributed/single mononuclear cells, dotted arrows: area without mononuclear cells. (H&I) Arrows/dotted arrows: corresponding areas to (G)

Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis-1

<p><b>Copyright information:</b></p><p>Taken from "Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis"</p><p>http://www.translational-medicine.com/content/5/1/63</p><p>Journal of Translational Medicine 2007;5():63-63.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2234395.</p><p></p>phaSMA- (SMA) and vimentin-positive (VIM) structures are endothelia, CD31 staining was performed. (D-F) In areas of loosely packed mononuclear cells (arrowhead in D) and packed mononuclear cells (white arrow in D), there is sparse immunoreactivity for collagen1 (arrowhead and white arrow in E) and moderate staining for fibronectin (arrowhead and white arrow in F). In areas with a low number of CD45-positive mononuclear cells (dotted arrow in D), the staining intensities for collagen1 (dotted arrow in E; COL) and fibronectin (dotted arrow in F; FBN) are stronger. Original magnification: ×200