Effect of pentoxifylline on hepatic ischemia and reperfusion injury

Neutrophil Elastase Inhibitor Increases Flap Survival in Experimental Degloving Injuries

Objectives:

Degloving hand injuries have generally been viewed as among the most difficult of injuries to manage due to the extensive nature of associated damage. The traditional approach to the circumferentially degloved segment of problematic flap viability has been to resuture the flap and to wait and see. However, the waiting period or the specific hemorheological protocol remains uncertain. This study aims to acknowledge if Sivelestat, known to ameliorate ischemia-reperfusion injury, enhances the survival of avulsed flaps in a hind limb degloving model of rats and to compare Sivelestat’s effects to Pentoxifylline.

Methods:

In this study, total flap area (cm²), area of necrosis in the flap (cm²), and the ratio between the necrotic and total areas (percentage) were determined. Angiogenesis among the groups was documented with CD31, anti-PECAM staining. TUNEL assay was performed to allow the visualization of cell nuclei containing fragmented DNA, a typical feature of apoptosis.

Results:

The findings obtained in this study showed that Sivelestat administered at 10 mg/kg/hour dosage will inhibit the ischemia-reperfusion injury more pertinently than Pentoxifylline, which exerts only hemorheological effects.

Conclusion:

The anti-inflammatory effects of Sivelestat will be beneficial for decreasing the early complications of degloving injury, such as inflammation, sepsis, and edema, better than Pentoxifylline, which exerts only hemorheological effects.

Pentoxifylline in liver ischemia and reperfusion

Pentoxifylline is a methylxanthine compound which was first filed in 1973 and registered in 1974 in the United States by Sanofi-Aventis Deustchland Gmbh for the treatment of intermittent claudication for chronic occlusive arterial disease. This methylxanthine was later discovered to be a phosphodiesterase inhibitor. Furthermore, its hemorheological properties and its function as an inhibitor of inflammatory cytokines, like TNF-α, allowed researchers to study its effects in organ ischemia and reperfusion and transplantation. Although this drug has demonstrated beneficial effects, the mechanisms by which Pentoxifylline exerts a protective effect are not fully understood. This paper focuses on reviewing the literature to define the effect of Pentoxifylline when used in liver ischemia and reperfusion injury. Our research shows different animal models in which Pentoxifylline has been used as well as different doses and time of administration, as the ideal dose and timing have not yet been ascertained in liver ischemia and reperfusion. In conclusion, Pentoxifylline has shown positive effects in liver ischemia and reperfusion injury, and the main mechanism seems to be associated with the inhibition of TNF-α.

Curbing the focal adhesion kinase and its associated signaling events by pentoxifylline in MDA-MB-231 human breast cancer cells

Pentoxifylline (PTX) is a methylxanthine derivative currently being used in the treatment of peripheral vascular diseases. Recently, we had evaluated its action in human MDA-MB-231 breast cancer cells. PTX exhibited anti-metastatic activity by affecting key processes such as proliferation, adhesion, migration, invasion and apoptosis. In light of the preliminary findings, the present work accounts for the possible mechanistic insights of the pathways affected by PTX. Aberrant Focal Adhesion Kinase (FAK) signaling forms a key determinant in breast cancer and in view of this fact we had investigated downstream processes regulated by FAK. PTX at sub-toxic doses lowers the level of activated FAK, Extracellular Regulated Kinase or Mitogen Activated Protein Kinase (ERK/MAPK), Protein Kinase B (PKB/Akt) affecting cellular proliferation and survival. It blocks G1/S phase of cell cycle by inhibiting the expression of Cyclin D1/Cdk6. Further, it modulates the activities of RhoGTPases and alters actin organization resulting in decreased motility. PTX also delays tumor growth and inhibited blood vessel formation in vivo. In purview of these findings, PTX surely qualifies as a suitable prospect in the intervention of breast cancer.

Cyclooxygenase-2 inhibitor celecoxib in a rat model of hindlimb ischemia reperfusion

Acute ischemia–reperfusion (IR) of the limbs initiates both local and systemic injuries by triggering a systemic inflammatory response. Cyclooxygenase-2 (COX-2), an endogenous inducible enzyme, rises in response to inflammation. The aim of this work is to investigate the role of celecoxib, a selective COX-2 inhibitor, in abrogating remote organ dysfunction after hindlimb IR in rats by comparing it with a standard hemorrheologic drug (pentoxifylline). Rats were divided into 4 groups (n = 6 each), group I (sham control, received saline and was kept under anaesthetic for 7 h). Group II (IR, subjected to 1 h of hindlimb tourniquet ischemia and 6 h reperfusion). Group III and IV (pretreated with 200 mg/kg pentoxifylline or 10 mg/kg celecoxib, respectively, intragastrically for 7 days before IR induction). Administration of pentoxifylline or celecoxib produced significant reduction in SGPT, serum creatinine, malondialdehyde, and tumor necrosis factor-α and significant increase in blood pH, blood adenosine triphosphate, and reduced glutathione compared with the IR group (p < 0.05). There was no significant difference among the pretreated groups. Histopathologic findings of the IR lung showed alveolar destruction, inflammatory cells infiltration, mast cell degranulation, and necrosis of the gastrocnemius muscle fibres. These changes were attenuated in the pretreated groups. In conclusion, celecoxib can ameliorate IR induced remote organ injury to a similar extent as pentoxifylline through its antiinflammatory and antioxidant action.

Inhibition of tumor necrosis factor alpha gene transcription by pentoxifylline reduces normothermic liver ischemia-reperfusion injury in rats

Pentoxifylline (PTX) has been shown to protect the liver against normothermic ischemia-reperfusion (I-R) injury. The aims of this study were to investigate the action of PTX on tumor necrosis factor alpha (TNFalpha) gene transcription following normothermic liver I-R as well as to evaluate the resulting effects on liver function and survival. A segmental normothermic liver ischemia was induced for 90 minutes. Rats were divided into three groups: group 1, control, Ringer lactate administration; group 2, PTX treatment; group 3, sham-operated control rats. PTX (50 mg/kg) was injected intravenously 30 minutes before induction of ischemia and 30 minutes before reperfusion. The nonischemic liver lobes were resected at the end of ischemia. Survival rates were compared and serum activities of TNFalpha, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase were measured. Liver histology was assessed 6 hours after reperfusion. Liver TNFalpha mRNA was assessed by polymerase chain reaction amplification at different times after reperfusion. PTX treatment significantly decreased serum activities of TNFalpha and inhibited liver expression of TNFalpha mRNA. The extent of liver necrosis and serum levels of liver enzymes were significantly decreased by PTX treatment, resulting in a significant increase in 7-day survival compared with nontreated control rats. In conclusion, PTX inhibits liver TNFalpha gene transcription, decreases serum TNFalpha levels, and reduces liver injury following normothermic I-R.

The effects of pentoxifylline on liver regeneration after portal vein ligation in rats

AIM

To determine the effects of pentoxifylline, a methyl xanthine derivative on hepatic cell production of uninterferred lobe after portal vein branch ligation.

METHODS

Sixty-six rats were randomly allocated into 9 groups with 8 rats in PVL groups and 6 rats in sham operation groups. The portal branches of the median and the lateral liver lobes, corresponding to approximately 70% of the liver volume were ligated in the PVL groups. The control group received 0.9% NaCl solution. The rats in the treatment groups received pentoxifylline at the dose of 50 mg/kg/dy. After 1, 2, 4 days of portal vein ligation in both PVL and PVNL lobes the levels of adenine nucleotides were determined and flowcytometric analysis of cell cycles were performed.

RESULTS

On the first day of portal branch ligation energy charge was significantly lower, in pentoxifylline treated group comparing to pentoxifylline untreated group, both in PVL and PVNL lobes (P<0.05). Proliferative indexes were 0.38 and 0.29 in pentoxifylline treated and pentoxifylline untreated PVNL lobes respectively (P<0.05).

CONCLUSION

Pentoxifylline treatment resulted in an increase of percentage of calls entering mitosis phase on the first day after PVL, somehow accelerating the regeneration process.

Improving outcome in patients undergoing liver surgery

Liver surgery is associated with many factors, which may affect outcome. Preoperative assessment of patient's general condition, resectability, and liver reserve are paramount for success. The Child-Pugh score and other scoring systems only partially enables to assess the risk associated with liver surgery. The presence of portal hypertension per se is a major risk factor for hepatectomy. Intraoperatively, any attempts should be made to minimize blood loss. Low central venous pressure and inflow occlusion best prevent bleeding. Ischemic preconditioning and intermittent clamping are routinely applied in many centers to protect against long periods of ischemia, although the mechanisms of protection remain unclear. In this review we describe recent advances in activated pathways associated with protection against ischemia. Postoperatively, the best factor impacting on outcome probably resides in experienced medical care particularly in the intensive care setting. Currently, no drug or gene therapy approaches has reached the clinic. The future relies on new insight into mechanisms of ischemia-reperfusion injury.

Pentoxifylline inhibits liver expression of tumor necrosis factor alpha mRNA following normothermic ischemia-reperfusion

BACKGROUND

Pentoxifylline (PTX) has been shown to reduce hepatic injury after normothermic ischemia and reperfusion (I-R) in rat liver.

AIM

The aim of this study was to evaluate the effects of PTX on liver expression of tumor necrosis factor alpha (TNFalpha) mRNA following normothermic liver I-R.

MATERIALS AND METHODS

A segmental normothermic ischemia of the liver was induced in male Lewis rats by occluding the blood vessels including the bile duct to the median and left lateral lobes for 90 min. At the end of ischemia the nonischemic liver lobes were resected. Rats were divided into three groups: group 1, control Ringer lactate administration; group 2, PTX treatment; group 3, sham-operated control rats. PTX (50 mg/kg) was injected intravenously 30 min before and 60 min after induction of ischemia. Survival rates were compared and the serum activities of TNFalpha, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were measured. Histology of the liver was assessed 6 h after reperfusion. Liver TNFalpha mRNA was assessed by PCR amplification at 0, 60, 120, and 210 min after reperfusion.

RESULTS

PTX treatment significantly increased 7 day survival (93.3%) compared with nontreated control rats (46.6%, p<0.007). The extent of liver necrosis and the release of liver enzymes were significantly decreased after PTX treatment. Serum activities of TNFalpha were significantly decreased and liver expression of TNFalpha mRNA was inhibited after PTX treatment.

CONCLUSION

PTX protects the liver from ischemic injury and inhibits liver expression of TNFalpha mRNA.

The effect of pentoxifylline in treatment of skin degloving injuries: an experimental study

BACKGROUND

Management of skin degloving injuries is still a problematic issue and the avulsed part of the skin may become necrotic. In this pilot study, we attempted to develop an experimental model for degloving injuries and investigated the efficacy of pentoxifylline, a well-known potent agent in enhancement of erythrocyte flexibility and tissue vascularization, in treatment of this injury model.

METHODS

Degloving injuries were created in 15 rats' tails by circular puncturing of the skin at the middle of the tail and then applying moderate force to avulse the skin from the underlying tissue. Then, the skin was repaired back to its original position. No treatment was given in the first group (n=6). In the second group (n=3), 0.4cm(3) physiological serum was administered intraperitoneally for 10 days. In the third group (n=6), intraperitoneal 25mg/kg pentoxifylline was administered for 10 days. Tails were observed daily for 21 days and then examined histopathologically.

RESULTS

At the end of the study, the avulsed segment of the skin became cyanotic and ulcerated in the first and the second group, and in the third group, the skin was intact. In histopathological examination, loss of superficial ephitelium and dense infiltration of inflammatory cells were seen in groups 1 and 2, and the skin layers were normal in the group 3.

CONCLUSION

Pentoxifylline improved tissue preservation and was proved to be highly beneficial in treatment of skin degloving injuries.

Method of pyloric reconstruction and impact upon delayed gastric emptying and hospital stay after pylorus-preserving pancreaticoduodenectomy

Preservation of the pylorus at the time of pancreaticoduodenectomy has been associated with equal oncological outcomes when compared to the classical Whipple operation. Multiple studies have demonstrated that pylorus-preserving pancreaticoduodenectomy (PPPD) has equal or superior outcomes regarding quality of life when compared with the traditional Whipple operation, but many studies have suggested a higher incidence of delayed gastric emptying (DGE). DGE prolongs hospital stay, and its association with PPPD has hampered its adoption by many pancreatic surgery centers. We describe a novel surgical technique for the prevention of delayed gastric emptying following pylorus-preserving pancreaticoduodenectomy. The technique of pyloric dilatation appears to decrease the incidence of delayed gastric emptying and facilitates earlier hospital discharge, when compared with standard pylorus preserving pancreaticoduodenectomy.

Beneficial effect of pentoxifylline on microvesicular steatotic livers submitted to a prolonged cold ischemia

BACKGROUND

The deleterious effect of steatosis on transplanted livers is mainly related to a microcirculation impairment. We investigated the effect of preservation duration on the recovery of isolated perfused rat steatotic livers and tested the effect of pentoxifylline (PTX), known to have a beneficial effect on hepatic microcirculation.

MATERIALS AND METHODS

Fatty rat livers were obtained using a diet able to induce an 80% to 100% microvesicular steatosis within 7 days. We studied the effect of the duration of preservation (12 hr, 18 hr, and 24 hr) on fatty and normal isolated perfused rat liver. PTX was added to University of Wisconsin solution during cold storage (30 mM/kg of weight) and at reperfusion (3 mM) (n=5 livers in each group). Lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, bile production, and vascular resistance were evaluated. The liver injury at the end of perfusion was assessed by optical and electron microscopy.

RESULTS

For a 24-hr preservation period, fatty livers demonstrated increased enzymatic release (aspartate aminotransferase: 42+/-16 vs. 17+/-5 IU/L/g of liver, P<0.005; alanine aminotransferase: 32+/-13 vs. 13+/-3 IU/L/g of liver, P<0.005; lactate dehydrogenase: 1,207+/-497 vs. 291+/-195 IU/L/g of liver, P<0.001). Vascular resistance (0.32 vs. 0.15 cm H(2)O/min/mL, P<0.0005) and bile output (67+/-24 vs. 141+/-61 mg/g of liver, P<0.05) were decreased. Peliosis appeared after an 18-hr preservation period for fatty livers compared with a 24-hr preservation period for controls. All these negative effects were suppressed by PTX.

CONCLUSION

Diffuse microvesicular steatosis became deleterious only after long preservation times (24 hr). PTX prevented this effect.

The effects of pentoxifylline on bacterial translocation after intestinal obstruction

Bacterial translocation (BT) occurs mainly in preseptic conditions such as intestinal obstruction, trauma, and burn, and the underlying mechanisms are still unclear. Pentoxifylline (PTX) is a derivative of methyl xanthine and has several beneficial effects in sepsis. We investigated the effects of PTX on a rat BT model. Simple intestinal obstruction (IO) was choosen to create high BT rates. Rats were divided in to five groups of 10 rats. Either 50 mg/kg PTX or placebo (3 mg/100 g saline) was administered subcutaneously following IO, either by single injection or twice with a 12-h interval. All rats were sacrificed 12 or 24 h after the procedure, and mesenteric lymph nodes (MLN), liver, and blood samples were obtained under aseptic conditions for bacterial cultures. The samples were obtained 12 h following IO in the first two groups, and the same samples were obtained 24 h after IO in last three groups. Groups IV and V were the PTX treatment groups. PTX was re-injected 12 h after IO only in group IV. As a result, BT rates in MLNs and liver were found to be significantly low, blood specimens remained sterile in PTX-pretreated and -treated rats, and BT rates were high in control groups and group V (once treatment late specimen group). We conclude that simple intestinal obstruction causes BT, and PTX reduces BT in rats with IO during the first 12-h period if PTX is given once immediately following IO. PTX reduces BT during the first 24-h after IO provided that is injected twice with a 12-h interval. More experimental studies are need to explain the exact mechanism of this beneficial effect.

Beneficial effects of pentoxifylline pretreatment in non-heart-beating donors in rats

BACKGROUND

Pentoxifylline (PTX) pretreatment of recipients was shown to protect against liver graft failure from ischemia-reperfusion injury after orthotopic rat liver transplantation. It has also been shown that PTX protects against normothermic ischemia-reperfusion injury to the liver in lobar ischemia model in the rat. Whether PTX can benefit the liver procured from non-heart-beating donors (NHBDs) with up to 9 hr of cold ischemia is unknown.

METHODS

Donor and recipient rats were pretreated with intraperitoneal PTX (50 mg/kg) 1 hr before cardiac arrest and transplantation, respectively. Grafts were transplanted 0, 30, and 60 min after cardiac arrest with additional 1 and 9 hr of cold ischemia in both PTX-pretreated or untreated (control) groups (10 rats per group). PTX (25 mg/kg/day) was continuously given to the surviving rats for 5 days postoperatively. Recipient survival rates, serum enzyme levels, and histopathological examination of postreperfusion liver biopsies were all analyzed.

RESULTS

The survival rates, serum enzyme levels, and postreperfusion histology were significantly improved in groups pretreated with PTX compared to the controls.

CONCLUSION

Donor and recipient PTX pretreatment significantly improves the viability of the liver grafts procured from NHBDs.