Do the effects of pentoxifylline on the inflammatory process and pancreatic infection justify its use in acute pancreatitis?

Hemorheological and Microcirculatory Relations of Acute Pancreatitis

Acute pancreatitis still means a serious challenge in clinical practice. Its pathomechanism is complex and has yet to be fully elucidated. Rheological properties of blood play an important role in tissue perfusion and show non-specific changes in acute pancreatitis. An increase in blood and plasma viscosity, impairment of red blood cell deformability, and enhanced red blood cell aggregation caused by metabolic, inflammatory, free radical-related changes and mechanical stress contribute to the deterioration of the blood flow in the large vessels and also in the microcirculation. Revealing the significance of these changes in acute pancreatitis may better explain the pathogenesis and optimize the therapy. In this review, we give an overview of the role of impaired microcirculation by changes in hemorheological properties in acute pancreatitis.

Local and systemic effects of aging on acute pancreatitis

BACKGROUND

/Objectives: Evaluation of the local and systemic effects of aging on the severity of acute pancreatitis (AP) in an experimental rat model in elderly animals.

METHODS

AP was induced in Wistar rats by intraductal 2.5% taurocholate injection and divided into two groups: Young (3 month old) and Aged (18 month old). Two and 24 h after AP induction blood samples were collected for determinations of amylase, AST, ALT, urea, creatinine, glucose, and of plasma I-FABP. TNF-α and IL-6 levels were determined in serum and ascitic fluid. Liver mitochondrial function and malondialdehyde (MDA) contents, pancreas histological analysis, and pulmonar myeloperoxidade (MPO) activity were performed. Bacterial translocation was evaluated by bacterial cultures of pancreas.

RESULTS

A significant increase in serum amylase, AST, ALT, urea, creatinine, glucose, I-FABP, and IL-6 levels, and a reduction in serum and ascitic fluid TNF-α levels were observed in the aged group compared to the young group. Liver mitochondrial dysfunction, MDA contents, and pulmonary MPO activity were increased in the Aged AP group compared to the Young AP group. Positive bacterial cultures obtained from pancreas tissue in aged group were significantly increased compared to the young group. Acinar necrosis was also increased in aged AP group when compared to young AP group.

CONCLUSION

Aging worsens the course of acute pancreatitis evidenced by increased local and systemic lesions and increased bacterial translocation.

Effect of parenteral infusion of fish oil-based lipid emulsion on systemic inflammatory cytokines and lung eicosanoid levels in experimental acute pancreatitis

Parenteral fish oil lipid emulsion (FOLE) might mitigate inflammation after injury. Acute pancreatitis (AP) can occur following major surgery and is characterized by tissue and systemic release of inflammatory mediators that contributes to the systemic inflammatory response syndrome and multiple organ failure.

AIM

We evaluated the effect of short-term FOLE infusion before experimental induction of AP on systemic cytokine and lung eicosanoid profiles.

METHODS

Lewis rats (n = 72) received parenteral infusion of FOLE (FO group) or saline (SS group), or remained without parenteral infusion (CG group) for 48 h. Thereafter, AP was induced by retrograde injection of sodium taurocholate into the pancreatic duct. Animals were sacrificed after 2, 12 and 24 h. Blood and lung samples were collected to assess serum inflammatory cytokines (Luminex) and tissue eicosanoids (ELISA), respectively.

RESULTS

Serum TNF-α increased over time and serum IL-10 decreased from 12 to 24 h in CG group. In SS group serum TNF-α increased from 12 to 24 h (p = 0.039) and serum IL-10 decreased over time. Both CG and SS groups exhibited increased IL-6/IL-10 ratio (p = 0.040). From 12 to 24 h animals from FO group showed decreased serum IL-1 (p < 0.001), IL-4 (p < 0.002) and IL-6 (p = 0.050), and a trend towards increased IL-10 (p = 0.060). All experimental groups showed a trend towards increased PGE₂ and decreased LTB₄ in the lung at 24 compared with 12 h CONCLUSION: Parenteral infusion of FOLE for 48 h before the induction of experimental AP appears to favorably influence the cytokine response without affecting lung eicosanoids at the time points measured. The use of FOLE to prevent and treat AP following major surgery needs to be further explored.

Effects of intravenous administration of pentoxifylline in pancreatic ischaemia-reperfusion injury

BACKGROUND

Therapeutic strategies to reduce the occurrence of pancreatic ischaemia-reperfusion (I-R) injury might improve outcomes in human pancreas and kidney transplantation. In addition to its haemorrheologic effects, pentoxifylline has an anti-inflammatory effect by inhibiting NF-κB activation. This group has previously demonstrated that pentoxifylline induces an anti-inflammatory response in acute pancreatitis and liver I-R models. This led to the hypothesis that pentoxifylline might reduce pancreatic and renal lesions and the systemic inflammatory response in pancreatic I-R injury. The aim of this experimental study was to evaluate the effect of pentoxifylline administration in a rat model of pancreatic I-R injury.

METHODS

Pancreatic I-R was performed in Wistar rats over 1 h by clamping the splenic vessels. The animals submitted to I-R were divided into two groups: Group 1 (n = 20, control) rats received saline solution administered i.v. at 45 min after ischaemia, and Group 2 (n = 20) rats received pentoxifylline (25 mg/kg) administered i.v. at 45 min after ischaemia. Blood samples were collected to enable the determination of amylase, creatinine, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10. Pancreatic malondialdehyde (MDA) content, pancreas histology and pulmonary myeloperoxidase (MPO) were also assessed.

RESULTS

Significant reductions in serum TNF-α, IL-6 and IL-10 were observed in Group 2 compared with Group 1 (P < 0.05). No differences in pancreatic MDA content or serum amylase levels were observed between the two groups. The histologic score was significantly lower in pentoxifylline-treated animals, denoting less severe pancreatic histologic damage.

CONCLUSIONS

Pentoxifylline administration reduced the systemic inflammatory response, the pancreatic histological lesion and renal dysfunction in pancreatic I-R injury and may be a useful tool in pancreas and kidney transplantation.

Is there a therapeutic window for pentoxifylline after the onset of acute pancreatitis?

PURPOSE

To investigate the effects of pentoxifylline (PTX) in experimental acute pancreatitis (AP) starting drug administration after the induction of the disease.

METHODS

One hundred male Wistar rats were submitted to taurocholate-induced AP and divided into three groups: Group Sham: sham-operated rats, Group Saline: AP plus saline solution, and Group PTX: AP plus PTX. Saline solution and PTX were administered 1 hour after induction of AP. At 3 hours after AP induction, peritoneal levels of tumor necrosis factor (TNF)-α, and serum levels of interleukin (IL)-6 and IL-10 levels were assayed by Enzyme-Linked Immunosorbent Assay (ELISA). Determinations of lung myeloperoxidase activity (MPO), histological analysis of lung and pancreas, and mortality study were performed.

RESULTS

PTX administration 1 hour after induction of AP caused a significant decrease in peritoneal levels of TNF-α and in serum levels of IL-6 and IL-10 when compared to the saline group. There were no differences in lung MPO activity between the two groups with AP. A decrease in mortality was observed in the PTX treatment compared to the saline group.

CONCLUSIONS

Administration of PTX after the onset of AP decreased the systemic levels of proinflammatory cytokines, raising the possibility that there is an early therapeutic window for PTX after the initiation of AP.

Acute pancreatitis in two five-day-old Appaloosa foals

Severe acute pancreatitis (SAP) in foals is rare and treatment has not been documented. This paper describes the clinical, haematological and ultrasonographic findings as well as attempted treatment of SAP in two 5-day-old Appaloosa fillies. Clinical signs, including colic, diarrhoea and coma, may be mistaken for sepsis or neonatal encephalopathy. Hyperlipaemic serum and peritoneal fluid, and elevated serum and peritoneal fluid amylase and lipase activities aided the diagnosis. Severe acute pancreatitis should be included as a differential in an acutely ill foal with diarrhoea, colic, cerebral cortica dysfunction and hyperlipaemia.

Effects of pentoxifylline on intestinal bacterial overgrowth, bacterial translocation and spontaneous bacterial peritonitis in cirrhotic rats with ascites

BACKGROUND

Prophylaxis of spontaneous bacterial peritonitis with norfloxacin has been associated to development of antibiotic resistance. We investigated whether pentoxifylline compared to norfloxacin reduces bacterial translocation and spontaneous bacterial peritonitis in rats with CCl(4)-induced cirrhosis and ascites.

METHOD

After development of cirrhosis and ascites, animals were randomly allocated to receive pentoxifylline (16 mg/kg/d every 8h, oral route, n=13) or placebo (n=12) for 15 days. An additional group of 8 cirrhotic rats was given norfloxacin (5mg/kg/d for 15 days). Six healthy rats served as controls. Cecal flora and the prevalence of bacterial translocation and spontaneous bacterial peritonitis were analysed. Serum and ascitic fluid levels of TNF-alpha and cecal levels of malondialdehyde were also measured.

RESULTS

Pentoxifylline in comparison to placebo reduced intestinal bacterial overgrowth (21% vs. 67%, p=0.04), bacterial translocation to cecal lymph nodes (23% vs. 75%, p=0.03) and prevented spontaneous bacterial peritonitis (0% vs. 33%, p=0.04) by Enterobacteriaceae. Norfloxacin administration induced similar results. Pentoxifylline (0.18 ± 0.10 nmol/mg), but not norfloxacin (0.25 ± 0.13; p=0.02), significantly reduced cecal mucosal levels of malondialdehyde compared to placebo (0.33 ± 0.16; p=0.03).

CONCLUSION

In cirrhotic rats with ascites: (a) pentoxifylline as well as norfloxacin reduced intestinal bacterial overgrowth and bacterial translocation and prevented spontaneous bacterial peritonitis; (b) pentoxifylline, but not norfloxacin, reduced oxidative stress in cecal mucosal.

Effect of ageing on systemic inflammatory response in acute pancreatitis

Elderly patients show increased incidence of multiple organ dysfunction in acute pancreatitis possibly due to bacterial translocation. This is associated with increased susceptibility to infections in older people. Several reports have related this increased susceptibility to a proinflammatory status called inflammaging, which decreases the capacity of the immunological system to respond to antigens. Cellular senescence also contributes to this low-grade chronic inflammation in older subjects. We discuss here the effect of ageing on systemic inflammation, focusing on that induced by acute pancreatitis and some of the mechanisms involved. It is important to understand the immunological changes in the elderly to adjust treatment strategies in order to reduce the morbidity and mortality associated with acute pancreatitis and other conditions that lead to systemic inflammation.

Anti-inflammatory effects of peritoneal lavage in acute pancreatitis

OBJECTIVES

Intraperitoneal administration of trypsin stimulates the production of cytokines from peritoneal macrophages. Removing the pancreatitis-associated ascitic fluid from the peritoneal cavity may decrease the systemic inflammatory response in acute pancreatitis (AP). We investigated the effect of peritoneal lavage on the systemic inflammatory response in severe AP.

METHODS

Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Peritoneal lavage was performed for 4 hours after onset of AP. At 4 hours after induction of AP, serum samples were assayed for amylase and inflammatory cytokines (tumor necrosis factor α, interleukin-6 [IL-6], and IL-10). Expression of pancreatic cyclooxygenase-2 and inducible nitric oxide synthase, liver mitochondrial function, and pulmonary myeloperoxidase activities were determined.

RESULTS

Peritoneal lavage after AP led to a decrease in serum levels of tumor necrosis factor α and IL-6 and an increase in IL-10. In the pancreas, this treatment reduced cyclooxygenase-2 and inducible nitric oxide synthase expression. Liver mitochondrial dysfunction was also reduced. There were no differences on serum amylase levels and pulmonary myeloperoxidase between groups with AP.

CONCLUSIONS

Peritoneal lavage has a systemic anti-inflammatory effect in severe AP and may be able to decrease the severity of severe AP.

Inflammatory cytokines and intestinal barrier dysfunction in patients with severe acute pancreatitis

Severe acute pancreatitis (SAP) is often associated with intestinal barrier dysfunction (IBD). IBD is a sophisticated pathophysiological process that can lead to intestinal endotoxemia and induce systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Inflammatory cytokines play an important role in the pathogenesis of SAP with IBD. Nuclear factor- kappa B and high mobility group box l (HMGB1) are important inflammatory cytokines that mediate the systemic inflammatory response in patients with SAP and IBD.

Pharmacotherapy for acute pancreatitis

Our knowledge of acute pancreatitis is still far from complete and there is no unanimous agreement concerning the pathophysiological processes leading to typical alterations during the course of acute pancreatitis. We reviewed the paper published in the last decade on the pathophysiology and treatment of acute pancreatitis. It is difficult to translate the experimental therapeutic results into clinical practice. For example, lexipafant was efficacious in decreasing the severity and mortality of lethal pancreatitis in rats, but seems to have no effect on severe acute pancreatitis in humans. Thus, the main problem in acute pancreatitis, especially in the severe form of the disease, is the difficulty of designing clinical studies capable of giving reliable statistically significant answers regarding the benefits of the various proposed therapeutic agents previously tested in experimental settings. Thus, analgesia, supportive care, and treatment of the pulmonary and renal complications remain the cornerstones of the treatment of acute pancreatitis, especially in the severe form of the disease.