A novel diamino-pyridine derivative prevents excessive leukocyte infiltration in aggravation of acute necrotizing pancreatitis

Development of stabilized fuzapladib solution for injection: forced degradation study and pharmacokinetic evaluation

The aim of the present study was to develop and evaluate stabilized injection solutions of fuzapladib sodium hydrate using antioxidants as the stabilizers. To estimate the possible degradation factors and pathways of fuzapladib, forced degradation studies were conducted under thermal, acid, base, oxidative, and light conditions. To select an optimal excipient to stabilize fuzapladib under a solution state, a screening study of antioxidants was carried out to evaluate their effects to inhibit the degradation. The influence of the selected stabilizers on its pharmacokinetic behavior was evaluated in rats after intravenous administration. On the basis of data from the forced degradation study, thermal and oxidative stresses were significant factors accelerating the degradation of fuzapladib. Among eight tested antioxidants, vitamin C (VC) was the most effective stabilizer to suppress the accelerated degradation by heating, as evidenced by 45% inhibition of the degradation. The stabilization effect was enhanced depending on the concentration of VC. After the intravenous administration of fuzapladib (0.5 mg/kg) with or without VC (2.1 mg/kg), there were no significant differences between the pharmacokinetic behaviors of each group. From these findings, VC might be a promising excipient to stabilize the injection solution of fuzapladib without significant influence on its pharmacokinetic behavior.

Nanocrystal solid dispersion of fuzapladib free acid with improved oral bioavailability

This study aimed to develop an oral nanocrystal solid dispersion (nCSD) of fuzapladib (FZP) with enhanced absorbability for the treatment of acute pancreatitis (AP). The hydration properties of crystalline FZP free acid (crystalline FZP) and FZP sodium salt (FZP/Na) were assessed to select a stable crystal form. The nCSD of FZP free acid (nCSD/FZP) was prepared using a multi-inlet vortex mixer and evaluated in terms of physicochemical and pharmacokinetic properties. The results of X-ray powder diffraction analysis indicated that crystalline FZP was stable as an anhydrate, while FZP/Na was converted to its monohydrate at water activity of above 0.2. The nanocrystals in nCSD/FZP were dispersed in hydroxy propyl cellulose-SSL, and their mean particle size were 160 nm with uniform spherical shape. In dissolution testing, nCSD/FZP exhibited rapid dissolution compared with crystalline FZP and reached a saturated concentration of FZP within initial 30 min. After oral administration (2 mg-FZP/kg) to rats, the maximum plasma concentration and bioavailability were 7.3- and 5.2-fold higher for nCSD/FZP than crystalline FZP, respectively, due to improved dissolution by nanosization. In conclusion, nCSD/FZP may be a novel oral dosage form with enhanced absorbability facilitating potent therapeutic effects of FZP for the treatment of AP in animals.

The protective effects of taurine on experimental acute pancreatitis in a rat model

The aim of this study was to investigate the protective effects of taurine (Tau) on experimental acute pancreatitis (AP) in a rat model by measuring cytokines and oxidant stress markers.

Forty rats were randomly divided into four groups: sham, AP, Tau and AP + Tau. AP was induced with sodium taurocholate. No treatment was given to the AP. All rats were killed 5 days later. Pancreatic tissues of rats and blood samples were obtained.

Tau treatment significantly decreased serum amylase activity ( p < 0.001), total injury score ( p < 0.001), malondialdehyde levels ( p < 0.001) and myeloperoxidase (MPO) activity ( p < 0.001). There was no significant difference between the Tau and AP + Tau groups in serum and pancreatic tumor necrosis factor-α, interleukin (IL)-1β and IL-6 levels ( p = 1.000). Histopathologic scores in the AP + Tau and Tau groups were significantly lower compared with the AP group (both p < 0.001).

These results showed that Tau reduces lipid peroxidation, amylase and MPO activities and the concentrations of proinflammatory cytokines secondary to AP and also increases superoxide dismutase and glutathione peroxidase activities in rats with sodium taurocholate-induced AP. It also has a marked ameliorative effect at histopathologic lesions. With these effects, Tau protects the cells from oxidative damage, reduces inflammation and promotes regression of pancreatic damage.

Ameliorative effect of adalimumab on experimentally induced acute pancreatitis in rats

OBJECTIVES

In this study, the effects of adalimumab (ADA), a fully humanized IgG1 monoclonal antibody to tumor necrosis factor α, on experimentally acute pancreatitis (AP) were examined.

METHODS

Healthy Wistar rats (n = 32) were randomly divided into 4 groups: group 1, AP; group 2, AP + ADA; group 3, control (physiologic saline), and group 4, physiologic saline + ADA (n = 8/group). Acute pancreatitis was induced with a retrograde injection of 3% sodium (Na)-taurocholate into the common biliopancreatic duct. Adalimumab was simultaneously administered at 50 mg/kg intraperitoneally for groups 2 and 4. Physiologic saline was administered instead of Na-taurocholate for non-AP groups. After 24 hours, serum amylase, lactate dehydrogenase, pancreatic myeloperoxidase, and malondialdehyde activities, along with pancreatic histopathology, were examined.

RESULTS

Adalimumab treatment significantly decreased serum amylase activity (AP, 2778.25 ± 298.80; AP + ADA, 2143.13 ± 221.69; control, 1541.00 ± 148.39; ADA, 1143.00 ± 256.30 U/L; P < 0.001), lactate dehydrogenase activity (AP, 2978.37 ± 364.65; AP + ADA, 2582.75 ± 164.23; control 931.25 ± 135.93; ADA, 582.62 ± 99.37 U/L; P < 0.001), myeloperoxidase activity (AP, 1.44 ± 0.20; AP + ADA, 0.86 ± 0.01; control, 0.60 ± 0.17; ADA, 0.41 ± 0.00 U/g of wet tissue; P < 0.001), malondialdehyde activity (AP, 16.94 ± 3.98; AP + ADA, 7.66 ± 2.27; control, 9.07 ± 1.00; ADA, 3.58 ± 0.30 nmol/g; P < 0.01), and total histopathologic scores (AP, 2.75 ± 0.16; AP + ADA, 1.50 ± 0.19; control, 0.00 ± 0.00; ADA, 0.00 ± 0.00; P < 0.001).

CONCLUSIONS

These results support the idea that adalimumab might be beneficial for severity of AP.

Effects of dexamethasone on intercellular adhesion molecule 1 expression and inflammatory response in necrotizing acute pancreatitis in rats

OBJECTIVES

Adhesion molecules are involved in the inflammatory response during acute pancreatitis (AP). We investigated the effect of dexamethasone (Dx) on intercellular adhesion molecule 1 (ICAM-1) expression during AP and its consequences on leukocyte recruitment and pancreatic damage.

METHODS

Acute pancreatitis was induced in rats by 3.5% sodium taurocholate for 3 hours and 6 hours. Dexamethasone (1 mg/kg) was administered either 30 minutes before or 1 hour after inducing AP. Messenger RNA ICAM-1 expression in pancreas and lung, membrane-bound ICAM-1 in acinar cells, and ICAM-1 plasma levels were analyzed. Histological examination of the pancreas and neutrophil infiltration in pancreas and lung were also measured.

RESULTS

Prophylactic and therapeutic administration of Dx down-regulated ICAM-1 expression in pancreas and lung from early AP. Dexamethasone given before AP reduced the pancreatic damage, but lung inflammation was not prevented. Therapeutic Dx treatment was ineffective in avoiding leukocyte recruitment into the pancreas and lung in rats with AP. High ICAM-1 concentration was found in plasma during AP, which was not reduced by Dx treatments.

CONCLUSIONS

Dexamethasone down-regulates ICAM-1 expression, but it does not completely prevent leukocyte recruitment during sodium taurocholate-induced AP.

Effects of IS-741, a synthetic anti-inflammatory agent, on bleomycin-induced lung injury in mice

Bleomycin (BLM)-induced lung injury consists of excessive inflammatory cell infiltration and fibrosis. IS-741 has been reported to be an anti-inflammatory drug through an inhibitory action on cell adhesion. In this study we investigated whether IS-741 could inhibit the progression of pulmonary fibrosis through inflammatory cell infiltration. Lung injury was induced in female C57BL/6 mice by intratracheal instillation of BLM. IS-741 was administered daily intraperitoneally. The hydroxyproline content and fluid content in the lung on Day 28 were significantly lower in the IS-741-treated mice. The histological degree of lung injury or fibrosis was reduced in IS-741-treated mice. Administration of IS-741 caused significant reduction in the absolute number of total cells, monocyte chemoattractant protein (MCP)-1, and cysteinyl leukotriene (cysLTs) levels in bronchoalveolar lavage fluid on Day 7. Furthermore, the hydroxyproline content was significantly lower in IS-741-treated mice even though IS-741 was started on Day 14 after BLM instillation. Treatment with IS-741 had an inhibitory effect on BLM-induced lung injury and fibrosis via the repression of MCP-1 or cysLTs in this murine experimental model.

IS-741 attenuates local migration of monocytes and subsequent pancreatic fibrosis in experimental chronic pancreatitis induced by dibutyltin dichloride in rats

OBJECTIVES

Chronic pancreatitis consists of excessive leukocyte infiltration and fibrosis. IS-741 has been reported to be an antiinflammatory drug through an inhibitory action on cell adhesion. In this study, we investigated whether IS-741 could inhibit the progression of pancreatic fibrosis through monocyte infiltration. Moreover, we investigated the effect of IS-741 on rat pancreatic stellate cells (PSCs).

METHODS

Chronic pancreatitis was induced by dibutyltin dichloride in rats. From days 7 to 28 after dibutyltin dichloride application, IS-741 or distilled water was administered. At days 14 and 28, histological [hematoxylin-eosin stain and immunostain for ED1 and [alpha] smooth muscle actin (alpha-SMA)] and biochemical evaluations (intrapancreatic amylase, protein, cytokines, chemokines, and alpha-SMA) were performed. In vitro, rat PSCs were incubated with cytokine, chemokine, and growth factor simultaneously with IS-741, and their proliferation and activation were examined.

RESULTS

Histologically, IS-741 inhibited pancreatic fibrosis and decreased the number of ED1- and [alpha]-SMA-positive cells. The intrapancreatic expression of cytokines, chemokine, and [alpha]-SMA were also decreased. In vitro, IS-741 has no direct effect on the proliferation, alpha-SMA expression, and collagen synthesis of PSCs.

CONCLUSIONS

These results suggest that IS-741 suppressed macrophage infiltration and subsequent pancreatic fibrosis and that the infiltration of monocytes into pancreas is essential for pancreatic fibrosis.

Pancreatic proteases in serum induce leukocyte-endothelial adhesion and pancreatic microcirculatory failure

BACKGROUND

Neutrophil-mediated tissue injury in acute pancreatitis includes a severe reduction of the functional microcirculation via interaction of adhesion molecules on leukocytes (MAC-1) and endothelium (ICAM-1). The hypothesis of the study was that trypsin and elastase in serum alone lead to the expression of these complementary adhesion molecules and result in increased leukocyte-endothelial interaction (LEI). In addition we evaluated the preventative benefit of protease inhibition on these mechanisms.

MATERIALS AND METHODS

In vitro: Cultured endothelial cells (HUVEC) and human leukocytes (PMN) were stimulated with increasing doses of trypsin and elastase. In addition, pre-treatment of PMN or HUVEC was performed with protease inhibitors (Nafamostat mesilate, FUT and gabexate mesilate, FOY). The expression of ICAM-1 or MAC-1 was evaluated by flow cytometry. In vivo: Severe pancreatitis was induced in rats. Microcirculatory disturbances were evaluated by real-time confocal microscopy at 9 h in controls and acute pancreatitis with or without anti-protease treatment. Additionally, the effect of continuous trypsin and elastase infusion on pancreatic microcirculation and LEI were evaluated by intravital fluorescence videomicroscopy.

RESULTS

Up-regulation of MAC-1 and ICAM-1 expression requires the presence of serum. The maximal increase of MAC-1 and ICAM-1 expression was found at concentrations of trypsin or elastase characteristic for acute pancreatitis. FUT or FOY significantly reduced protease-induced expression of MAC-1 and ICAM-1. Real-time in-vivo microscopy revealed that functional capillary density in acute pancreatitis was significantly reduced (267.1 +/- 2.95/mm2 vs. 91.29 +/- 12.81/mm2) and treatment with FUT significantly reduced this effect (134.6 +/- 4.6/mm2; p < 0.05 vs. untreated pancreatitis). Infusion of trypsin or elastase alone increased LEI in vivo and reduced pancreatic perfusion.

CONCLUSION

Both trypsin and elastase up-regulate the expression of adhesion molecules on leukocytes and endothelial cells in the presence of serum. Increased LEI and reduced perfusion of the pancreas, characteristic of acute pancreatitis, is induced in vivo by infusion of pancreatic proteases and this effect is partially abrogated by their inhibitors. These results support the role of circulating trypsin and elastase in promoting pancreatic microcirculatory failure in experimental acute pancreatitis.

Potential role of endocrine gastrin in the colonic adenoma carcinoma sequence

The role of hyper-gastrinaemia in the incidence of colonic cancer remains to be clarified. The aim of this study was to determine whether cholecystokinin-2 (CCK-2) receptor expression predicts the sensitivity of human colonic adenomas to the proliferative effects of serum hyper-gastrinaemia. Gene expression of the classical (74 kDa) CCK-2 receptor in human colonic adenoma specimens and cell lines, was quantified by real-time PCR. Western blotting, using a CCK-2 receptor antiserum, confirmed protein expression. A transformed human colonic adenoma was grown in SCID mice, with hyper-gastrinaemia induced by proton pump inhibitors. CCK-2 receptor blockade was achieved by using neutralising antiserum. Both human colonic adenoma cell lines and biopsies expressed CCK-2 receptor mRNA at levels comparable with CCK-2 receptor transfected fibroblasts and oxyntic mucosa. Western blotting confirmed immunoreactive CCK-2 receptor bands localised to 45, 74 and 82.5 kDa. Omeprazole and lansoprazole-induced hyper-gastrinaemia (resulting in serum gastrin levels of 34.0 and 153.0 pM, respectively) significantly increased the weight of the human adenoma grafts (43% (P=0.016) and 70% (P=0.014), respectively). The effect of hypergastrinaemia on tumour growth was reversed by use of antiserum directed against the CCK-2 receptor. Hyper-gastrinaemia may promote proliferation of human colonic adenomas that express CCK-2 receptor isoforms.

Efficacy of the inflammatory cell infiltration inhibitor IS-741 on colitis induced by dextran sulfate sodium in the rat

We examined the therapeutic effects of the inflammatory cell infiltration inhibitor IS-741 (N-(2-((ethylsulfonyl)amino)-5-(trifluoromethyl)-3-pyridinyl)-cyclohexanecarboxamide monosodium salt monohydrate) on a rat colitis model. As a result of its effects on leukocyte infiltration, IS-741 inhibits cell adhesion, alleviates symptoms and signs of pancreatitis and multiple organ failure and demonstrates a life-saving effect in a model of severe acute pancreatitis. A rat model was prepared by inducing colitis with 3% dextran sodium sulfate (DSS) and maintaining pathology with 1% DSS. Repeated oral administration of IS-741 at 1, 10 or 100 mg/kg per day was conducted for 2 weeks (during treatment with 1% DSS). IS-741 at each dose decreased the area of erosion in the large intestine, thickening of the wall of the large intestine and anemia caused by melena. Some effects of IS-741 were nearly equivalent to those of the control compound salazosulfapyridine. Furthermore, IS-741 markedly alleviated inflammatory cell infiltration into the intestinal wall. IS-741 improved lesions in a rat DSS model by inhibiting leukocyte infiltration, suggesting the possibility of clinical application of this drug for IBD.

Opsonin receptor expression on peritoneal exudative and circulatory neutrophils in murine acute pancreatitis

Acute severe (necrotizing) pancreatitis is often associated with pancreatic or peripancreatic infection. Decreased bacterial clearance due to impaired immune defense may cause local infection. We investigated expressions of surface opsonin receptors (CD11b, complement receptor 3; CD32/CD16, immunoglobulin G Fc receptor) on local and circulatory neutrophils, in murine acute pancreatitis. The mild and severe forms of acute pancreatitis were induced by seven and 13 subcutaneous injections of caerulein, respectively. Peritoneal exudative and circulatory neutrophils were counted and assayed for receptor expressions by flow cytometry, serially at 1-72 hours after pancreatitis induction. Histologically, mild and severe forms showed edematous and necrotizing pancreatitis, respectively. The peritoneal exudative neutrophil count was greater in mild than in severe pancreatitis. Expressions of CD11b and CD32/CD16 on local neutrophils were upregulated early in mild pancreatitis. This upregulation was attenuated in severe pancreatitis. The circulatory neutrophil count was elevated in severe pancreatitis but was unchanged in mild pancreatitis. Opsonin receptor expression on circulatory neutrophils showed a transient, modest upregulation in the early phase of mild pancreatitis. Receptor-positive circulatory neutrophils showed a marked elevation that persisted throughout the course of severe pancreatitis. In conclusion, severe (necrotizing) pancreatitis is associated with reduced opsonin receptor expression on local neutrophils and enhanced expression on circulatory neutrophils, as compared with mild (edematous) pancreatitis. These changes may contribute to local infectious complications and multiple organ failure, in severe pancreatitis.