Effect of pentoxifylline on tissue injury and platelet-activating factor production during ischemia-reperfusion injury

Investigation of the effects of pentoxifylline and alpha tocopherol treatment on recovery in rats with Achilles tendon rupture

Although the Achilles tendon is the largest and strongest tendon in the body, healing of the Achilles tendon is the most common injury, and this process is difficult due to poor tendon circulation; moreover, the underlying mechanism has not been fully elucidated. In our study, we aimed to investigate the effects of pentoxifylline and alpha-tocopherol administered separately or in combination on rats with Achilles tendon injury. Forty-eight male Wistar rats weighing 230 ± 30 g were used in the study. The rats were randomly divided into eight groups of six animals each. Tendons were evaluated histopathologically and biomechanically. According to the statistical analysis, the vascularity density in the pentoxifylline group on day 14 was significantly greater than that in the other groups (p < 0.05). The collagen arrangement in the pentoxifylline and alpha-tocopherol groups on day 14 was found to be firmer and smoother than that in the control group (p < 0.05). The collagen arrangement in the pentoxifylline group on day 28 was greater than that in the other groups (p < 0.05). The biomechanical results were significantly greater in all groups (p < 0.05). Pentoxifylline contributed to tendon healing both through neovascularization in the early period and by improving collagen orientation in the late period, while alpha-tocopherol had a positive effect on collagen orientation in the early period. No beneficial effects were observed when pentoxifylline and alpha-tocopherol were used together. We believe that further research is needed to understand the effects of this combination therapy on tendon healing.

Radio-iodination and biological evaluation of pentoxifylline as a novel probe for diagnosis of intermittent claudication

The diagnosis of intermittent claudication (IC) is challenging. Imaging with radiopharmaceuticals provides a new method for detecting acute IC. Pentoxifylline improves blood flow to ischemic tissues via increasing erythrocyte elasticity and inhibiting platelet aggregation. Pentoxifylline was radio-iodinated with radioiodine-131 (¹³¹I) through a direct electrophilic substitution reaction. Furthermore, various factors that might influence the radiolabeling strategy were investigated. The radiochemical yield of [¹³¹I]iodopentoxiphyline was evaluated by using paper chromatography and HPLC methods. The biodistribution pattern of [¹³¹I]iodopentoxiphyline was studied, where Swiss albino mice was used as a model of acute limb ischemia-reperfusion. The maximum radiochemical yield of pentoxifylline was found to be 94.11 ± 2.35%. The biodistribution findings revealed that [¹³¹I]iodopentoxiphyline was significantly deposited at the ischemic site (left hind limbs), with encouraging target/non-target (T/NT) ratios. At 0.25 and 1 h post injection, the uptake of [¹³¹I]iodo-pentoxifylline was 5.30 ± 0.30 and 9.98 ± 1.12%, respectively. Also, the maximum T/NT ratio for [¹³¹I]iodo-pentoxifylline (9.45 ± 0.26) was obtained at 0.25 h post injection. Due to safety and selectivity, [¹³¹I]iodo-pentoxifylline may be a good prospective diagnostic tool for early identification of IC. Moreover, the outcome of this study can be expected to apply to I-123 as well.

Restorative potential of (-)-epicatechin in a rat model of Gulf War illness muscle atrophy and fatigue

We examined in a rat model of Gulf War illness (GWI), the potential of (-)-epicatechin (Epi) to reverse skeletal muscle (SkM) atrophy and dysfunction, decrease mediators of inflammation and normalize metabolic perturbations. Male Wistar rats (n = 15) were provided orally with pyridostigmine bromide (PB) 1.3 mg/kg/day, permethrin (PM) 0.13 mg/kg/day (skin), DEET 40 mg/kg/day (skin) and were physically restrained for 5 min/day for 3 weeks. A one-week period ensued to fully develop the GWI-like profile followed by 2 weeks of either Epi treatment at 1 mg/kg/day by gavage (n = 8) or water (n = 7) for controls. A normal, control group (n = 15) was given vehicle and not restrained. At 6 weeks, animals were subjected to treadmill and limb strength testing followed by euthanasia. SkM and blood sampling was used for histological, biochemical and plasma pro-inflammatory cytokine and metabolomics assessments. GWI animals developed an intoxication profile characterized SkM atrophy and loss of function accompanied by increases in modulators of muscle atrophy, degradation markers and plasma pro-inflammatory cytokine levels. Treatment of GWI animals with Epi yielded either a significant partial or full normalization of the above stated indicators relative to normal controls. Plasma metabolomics revealed that metabolites linked to inflammation and SkM waste pathways were dysregulated in the GWI group whereas Epi, attenuated such changes. In conclusion, in a rat model of GWI, Epi partially reverses detrimental changes in SkM structure including modulators of atrophy, inflammation and select plasma metabolites yielding improved function.

Pentoxifylline for the prevention of contrast-induced nephropathy in diabetic patients undergoing angioplasty: a randomized controlled trial

OBJECTIVES

Contrast-induced nephropathy (CIN) is one of the most important complications of contrast media. We aimed to evaluate the preventive effects of pentoxifylline (PTX) on CIN in diabetic patients undergoing angioplasty using cystatin C.

MATERIALS AND METHODS

The present study was a randomized clinical trial, which was investigated the impact of PTX in the prevention of CIN among 90 diabetic patients undergoing the angioplasty using cystatin C as a novel biomarker of renal injury. The patients randomly were allocated 1:1 into the intervention and the control groups. The intervention group received a total of 1200 mg PTX orally before the angioplasty. The serum level of cystatin C and creatinine was measured at baseline and 24 h after the procedure.

RESULTS

The incidence of CIN was 8.9% in the PTX group vs. 6.7% in the control group (p = 1.00). The baseline level of cystatin C was 1.31 ± 0.39 mg/L in the PTX group and 1.24 ± 0.42 mg/L in the control group (p = 0.561). After angioplasty, the level of cystatin C was increased to 1.33 ± 0.61 in PTX group and to 1.31 ± 0.47 in the control group but was not statistically significant. The similar pattern was also seen in the level of serum creatinine.

CONCLUSIONS

The results of this study did not support the potential benefit of PTX in the prevention of CIN in diabetic patients undergoing angioplasty.

Protective effects of pentoxifylline in small intestine after ischemia-reperfusion

Objective

This study was performed to determine the healing effects of pentoxifylline on molecular responses and protection against severe ischemic damage in the small intestine.

Methods

Thirty-six Wistar albino rats were divided into six groups. The superior mesenteric artery was clamped for 120 minutes, and reperfusion was performed for 60 minutes. Saline (0.4 mL), pentoxifylline (1 mg/kg), and pentoxifylline (10 mg/kg) were intraperitoneally administered to the rats in the C₁, P₁, and P₃ groups, respectively, 60 minutes before ischemia and to the rats in the C₂, P₂, and P₄ groups, respectively, during reperfusion onset. Malondialdehyde, myeloperoxidase, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 in serum and tissue were measured by enzyme-linked immunosorbent assay. Intestinal ischemic injury was histopathologically evaluated by the Chiu score and immunohistochemical staining.

Results

All serum and tissue molecular responses were significantly blunted in the pentoxifylline-treated groups compared with the controls. Significant improvement in ischemic damage was demonstrated in the pentoxifylline-treated groups by histological grading and immunohistochemical scoring.

Conclusions

The protective effects of pentoxifylline were confirmed by molecular responses and histopathological examination.

Effect of Pentoxifylline in Ameliorating Myocardial Injury in Patients With Myocardial Infarction Undergoing Thrombolytic Therapy: A Pilot Randomized Clinical Trial

Cell death following acute myocardial infarction (MI) is the hallmark pathology of cardiovascular disease, leading to considerable mortality and morbidity. Platelet and neutrophil activation and inflammatory cytokines, prominently TNF-α, play an important role in the development of cell death. Because pentoxifylline inhibits platelet and neutrophil activation and reduces TNF-α, this study was performed to assess the potential benefit of pentoxifylline in the reduction of myocardial injury following acute MI. In this randomized clinical trial, 98 patients with acute MI were randomly divided into 2 groups. The intervention group received an oral dose of 1200 mg of pentoxifylline immediately before thrombolytic therapy (TLT). All patients received the same standard protocol for treatment of MI. Cardiac enzymes were checked over 48 hours. ST resolution was measured over 90 minutes. Then all patients were followed up for a 1-month period to assess major adverse cardiac effects (MACEs). There were no significant differences in peak levels of CPK (P = .18) and CK-MB (P = .33) between the 2 groups, whereas peak level of troponin I was significantly lower in the pentoxifylline group (16.8 ± 10.4 vs 21.3 ± 11.6; P = .048). No significant change between the groups was observed in biomarkers levels, ST segment resolution, cardiac ejection fraction, and MACEs. The results showed that pentoxifylline significantly reduced the peak value of troponin I in patients with acute MI receiving TLT. No significant change was observed in the other studied parameters. Further outcome-based studies are needed to show the clinical relevance of differences between the groups in troponin peak.

Pharmacology of Ischemia-Reperfusion. Translational Research Considerations

Ischemia-reperfusion (IRI) is a complex physiopathological mechanism involving a large number of metabolic processes that can eventually lead to cell apoptosis and ultimately tissue necrosis. Treatment approaches intended to reduce or palliate the effects of IRI are varied, and are aimed basically at: inhibiting cell apoptosis and the complement system in the inflammatory process deriving from IRI, modulating calcium levels, maintaining mitochondrial membrane integrity, reducing the oxidative effects of IRI and levels of inflammatory cytokines, or minimizing the action of macrophages, neutrophils, and other cell types. This study involved an extensive, up-to-date review of the bibliography on the currently most widely used active products in the treatment and prevention of IRI, and their mechanisms of action, in an aim to obtain an overview of current and potential future treatments for this pathological process. The importance of IRI is clearly reflected by the large number of studies published year after year, and by the variety of pathophysiological processes involved in this major vascular problem. A quick study of the evolution of IRI-related publications in PubMed shows that in a single month in 2014, 263 articles were published, compared to 806 articles in the entire 1990.

Pentoxifylline for vascular health: a brief review of the literature

Pentoxifylline is a methylxanthine derivative that has been used for several decades in the symptomatic management of intermittent claudication. For reasons that remain fairly obscure, this drug benefits blood rheology in a number of complementary ways: decreasing blood and plasma viscosity, lowering plasma fibrinogen while promoting fibrinolysis, and improving blood filterability by enhancing erythrocyte distensibility and lessening neutrophil activation. Anti-inflammatory effects on neutrophils and macrophage/monocytes—some of them attributable to pentoxifylline metabolites—appear to play a mediating role in this regard. Although clinical trials with pentoxifylline have often been too small in size to reach statistically significant findings regarding impacts on hard end points, a review of the existing literature suggests that pentoxifylline may have potential for slowing the progression of atherosclerosis, stabilising plaque, reducing risk for vascular events, improving the outcome of vascular events, dampening the systemic inflammatory response following cardiopulmonary bypass, providing symptomatic benefit in angina and intermittent claudication, enhancing cerebral blood flow in patients with cerebrovascular disease while slowing progression of vascular dementia, improving prognosis in congestive heart failure, and aiding diabetes control. This safe and usually well-tolerated drug works in ways quite distinct from other drugs more commonly used for cardiovascular protection, and hence may confer complementary benefit when used in conjunction with them. Major clinical trials of adequate statistical power are now needed to confirm the scope of benefits that pentoxifylline can confer; studies evaluating hard end points in acute coronary syndrome, stroke/transient ischaemic attack and systolic heart failure might be particularly valuable.

Beneficial effect of pentoxifylline into the testis of rats in an experimental model of unilateral hindlimb ischemia/reperfusion injury

Objective

The objective of the present study was to investigate the role of pentoxifylline (PTX) on remote testicular injury caused by unilateral hind limb ischemia/reperfusion of rats.

Materials and Methods

Twenty healthy male Wistar rats were allocated randomly into two groups: ischemia/reperfusion (IR group) and ischemia/reperfusion + pentoxifylline (IR+PTX group). Ischemia was induced by placement of a rubber tourniquet at the greater trochanter for 2h. Rats in IR+PTX group received PTX (40 mg/kg IP) before the reperfusion period. At 24h after reperfusion, testes were removed and levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and myeloperoxidase (MPO) activity were determined in testicular tissues. Three rats of each group were used for wet/ dry weight ratio measurement. Testicular tissues were also examined histopathologically under light microscopy.

Results

Activities of SOD and CAT in testicular tissues were decreased by ischemia/ reperfusion (P<0.05). Significantly increased MDA levels in testicular tissues were decreased by PTX treatment (P<0.05). MPO activity in testicular tissues in the IR group was significantly higher than in the IR+PTX group (P<0.05). The wet/dry weight ratio of testicular tissues in the IR group was significantly higher than in the IR+PTX group (P<0.05). Histopathologically, there was a statistically significant difference between two groups (P<0.05).

Conclusions

According to histological and biochemical findings, we conclude that PTX has preventive effects in the testicular injury induced by hind limb ischemia/reperfusion.

Efficacy of pentoxifylline and tadalafil in rat model of ischemic colitis

OBJECTIVE

The aim of this study is to investigate the efficacy of tadalafil against pentoxifylline in rat model of ischemic colitis (IC).

MATERIAL-METHODS

Thirty-two Wistar albino rats were subjected to laparotomy and left colon devascularization to create an IC model and then randomly placed into four groups. Group-1 (sham group) was administered 0.9% NaCl following laparotomy, group 2 (control group) was administered 0.9% NaCl following induced IC, group 3 was given pentoxifylline (n = 8), and group 4 was given tadalafil. On the third day; macroscopic findings, Gomella's ischemic area and Wallace scoring, histopathological analysis, and Chiu scoring were performed, and malondialdehyde (MDA) measurement in ischemic colon tissue was carried out through chemical analysis.

RESULTS

Significant differences were observed in acidic fluid, bowel dilatation, and serosal change (p < .05). The ischemic area measured 63.3 mm(2) in the control group, 2.8 mm(2) in the pentoxifylline group (p = .0001), and 2.4 mm(2) (p = .0001) in the tadalafil group. A significant difference was seen between the sham group and the control and pentoxifylline groups (p < .01), in terms of Wallace score and Chiu classification. Similarly, a significant difference was determined between the control group and pentoxifylline and tadalafil groups (p < .01), but no significant difference was established between the pentoxifylline group and tadalafil group (p = .33). MDA measurement was found on an average to be 63.7 in the control group, 22.7 in group 3 and 22.8 in group 4 (p = 001).

CONCLUSION

Although tadalafil is superior to pentoxifylline, both drugs are considered to have positive effects.

Food deprivation and social inequality may lead to oxidative damage: a study on the preventive role of melatonin in the male rat reproductive system

Spermatogenic cells are susceptible to oxidative stress and apoptosis. Food deprivation (FD) has been reported as a stressor that could increase reactive oxygen species. In the present study, FD-induced oxidative stress and apoptosis, as well as the protective effects of melatonin, were evaluated in the testes. Wistar rats in the control group were fed a standard diet, whereas a sham group was administered saline as the melatonin vehicle. A third group received daily injections of melatonin (5mgkg-1 bodyweight). These rats were further divided into four groups of rats that were either subjected to FD, FD + isolation, FD + melatonin injection and FD + melatonin injection + isolation. Testicular tissues were evaluated for malondialdehyde (MDA) and reduced glutathione (GSH) concentrations, as well as and DNA damage. FD increased MDA and reduced GSH concentrations, whereas melatonin treatment improved these parameters. Immunohistochemistry for capsase-3 and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling revealed that the number of apoptotic cells was increased in rats subjected to FD alone. Melatonin treatment offset the number of apoptotic cells following FD. The results provide evidence that FD can increase oxidative stress, leading to activation of apoptosis, and that melatonin has the ability to protect the testes against oxidative damage induced by FD.

Testicular morphology in spontaneously hypertensive rat model: oxidant status and stereological implications

Studies by researchers suggest that reductions in blood flow to the testis could play an important role in the pathogenesis of male infertility. As this oxygen-dependent organ functions in a state of near anoxia, such a decrease in blood flow may very likely have profound effects on the tissue morphology that ultimately would predispose to various forms of hypo-spermatogenesis with consequent compromise in reproductive capability. With varying opinions expressed by experts as to the actual culprit or potential pathway and/or effects of pathophysiology of testicular haemodynamics, it still remains debatable whether the observed degenerative changes in testicular tissue are the result of major or minor reductions in flow or the consequence of other vascular pathologies or even extraneous factors. Again, increasing age and male gender have been identified as the single independent risk factors for the occurrence of cardiovascular pathologies with sexual dimorphism highly debated. The investigation of these factors occurring under hypertensive states using the spontaneously hypertensive rat (SHR) as an experimental model has attracted substantial attention in recent past. This review examines the relationships and potential morphologic changes in the testicular tissue under conditions of perturbations in blood flow as seen in the SHR with a view to the proper understanding of the role(s) of various factors that contributes to male subfertility. A suggestion to the use of stereological methods for quantitating various measurements in a highly active and dynamic structure like the testis with its arterial system has been added as this may facilitate a better understanding of the mechanisms implicated under hypertensive conditions.

Pentoxifylline reduces chronic post-ischaemia pain by alleviating microvascular dysfunction

BACKGROUND

Microvascular dysfunction and ischaemia in muscle play a role in the development of cutaneous tactile allodynia in chronic post-ischaemia pain (CPIP). Hence, studies were designed to assess whether pentoxifylline (PTX), a vasodilator and haemorrheologic agent, relieves allodynia in CPIP rats by alleviating microvascular dysfunction.

METHODS

Laser Doppler flowmetry of plantar blood flow was used to examine the effects of PTX on CPIP-induced alterations in post-occlusive reactive hyperaemia (reflecting microvascular dysfunction), and von Frey testing was used to examine its effects on CPIP-induced allodynia. Time-course effects of PTX on allodynia and microvascular dysfunction were assessed early (2-8 days) and late (18-25 days) post-ischaemia/reperfusion (I/R) injury, and its effects on allodynia were also tested at 30 days post-I/R injury.

RESULTS

PTX (25 mg/kg) produced significant anti-allodynic effects throughout the 21-day time course, but was not effective 30 days post-I/R injury. In laser Doppler studies, the reduced reactive hyperaemia in early CPIP rats was significantly improved by PTX (25 mg/kg). Conversely, treatment with PTX at the same dose did not affect reactive hyperaemia in late CPIP rats, likely since reactive hyperaemia was not significantly reduced pre-drug in these animals.

CONCLUSION

Since poor tissue perfusion underlies early stages of CPIP pain, the ameliorative effect of PTX on microvascular dysfunction might account for its anti-allodynic effect in our experimental model of complex regional pain syndrome type I.

Effect of short-term treatment with levosimendan on oxidative stress in renal tissues of rats

The aim of this study is to evaluate the influences of short-term treatment with levosimendan (chemical formula: C14H12N6O) on oxidative stress and some trace element levels in renal tissues of healthy rats. A total of 20 male Wistar-albino rats were randomly divided into two groups, each consisting of 10 rats. Animals in the first group were not treated with levosimendan and served as control. Animals in the second group were injected intraperitoneally with 12 µg/kg levosimendan and served as levosimendan group. Animals in both the groups were killed 3 days after the treatment, and their kidneys were harvested for the determination of tissue oxidant/antioxidant statues and trace element levels in renal tissues. The tissue malondialdehyde level was significantly (p < 0.001) lower in levosimendan group than in controls. The protective enzyme activities such as superoxide dismutase, catalase, and glutathione peroxidase and antioxidant glutathione level were significantly (p < 0.001) higher in levosimendan group than in controls. It was concluded that levosimendan reduced oxidative stress by avoiding lipid peroxidation and production of reactive oxygen species, and overactivating and/or increasing the protective antioxidant enzyme levels in renal tissues of rats. It is supposed that this experimental study provides beneficial data for clinicians in the management of renal tissue damage related to obstruction and/or ischemia.

Short-term levosimendan treatment protects rat testes against oxidative stress

The objective of this study was to evaluate the effect of short-term levosimendan exposure on oxidant/antioxidant status and trace element levels in the testes of rats under physiological conditions. Twenty male Wistar albino rats were randomly divided into two groups of 10 animals each. Group 1 was not exposed to levosimendan and served as control. Levosimendan (12 µg/kg) diluted in 10 mL 0.9% NaCl was administered intraperitoneally to group 2. Animals of both groups were sacrificed after 3 days and their testes were harvested for the determination of changes in tissue oxidant/antioxidant status and trace element levels. Tissue malondialdehyde (MDA) was significantly lower in the levosimendan group (P < 0.001) than in the untreated control group and superoxide dismutase and glutathione peroxidase (GSH-Px) levels were significantly higher in the levosimendan group (P < 0.001). Carbonic anhydrase, catalase and GSH levels were not significantly different from controls. Mg and Zn levels of testes were significantly higher (P < 0.001) and Co, Pb, Cd, Mn, and Cu were significantly lower (P < 0.001) in group 2 compared to group 1. Fe levels were similar for the two groups (P = 0.94). These results suggest that 3-day exposure to levosimendan induced a significant decrease in tissue MDA level, which is a lipid peroxidation product and an indicator of oxidative stress, and a significant increase in the activity of an important number of the enzymes that protect against oxidative stress in rat testes.

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.

Post-ischemic treatment of pentoxifyline reduces cortical not striatal infarct volume in transient model of focal cerebral ischemia in rat

Previous studies reported that pentoxifylline (PTX) have a neuroprotective effect in the brain trauma and the global cerebral ischemia in the experimental models. However, the effect of PTX in transient model of focal cerebral ischemia has not been investigated yet. Therefore, this study was designed to investigate the effect of post-ischemic treatment of PTX on ischemic injuries in focal cerebral ischemic. Male Wistar rats (n=32) were assigned to control or PTX- (60 mg/kg i.p.) treated groups. PTX at dose 60 mg/kg i.p. administered at the beginning, or 1, or 3 h after ischemia. Focal cerebral ischemia was induced by middle cerebral artery occlusion, followed by 24-h reperfusion. At the end of 24 h ischemia, neurological dysfunction score was tested and infarct volumes were determined using triphenyltetrazolium chloride staining. Administration of PTX (60 mg/kg) at the beginning of ischemia, or 1, or 3 h after ischemia significantly reduces cortical infarct volumes by 43%, 40% and 41%, respectively. However, PTX did not significantly affect striatal infarct volumes and neurological dysfunction. The findings of the present study indicate that administration of PTX at least 3 h post-transient focal stroke reduces cortical brain ischemic damage in the rat model of transient focal cerebral ischemia.

Isquemia e reperfusão de músculo sóleo de ratos sob ação da pentoxifilina

CONTEXTO: A reperfusão de músculo esquelético piora as lesões já presentes no período de isquemia, pois a produção de espécies reativas de oxigênio, associadas à intensa participação de neutrófilos, amplia a reação inflamatória que induz alterações teciduais. OBJETIVO: Avaliar as alterações morfológicas e imuno-histoquímicas de músculo esquelético (sóleo) de ratos submetidos a isquemia e reperfusão com pentoxifilina. MÉTODOS: Sessenta ratos foram submetidos a isquemia do membro pélvico, por 6 horas, pelo clampeamento da artéria ilíaca comum esquerda. Após isquemia, os animais do grupo A (n = 30) foram observados por 4 horas, e os do grupo B (n = 30), por 24 horas. Seis animais constituíram o grupo simulado. Administrou-se pentoxifilina apenas no período de reperfusão em A2 (n = 10) e B2 (n = 10) e nos períodos de isquemia e reperfusão em A3 (n = 10) e B3 (n = 10). O músculo sóleo foi avaliado por análise histológica (dissociação de fibras, infiltrado leucocitário, necrose) e imuno-histoquímica (apoptose pela expressão da caspase-3). Foram aplicados os testes não-paramétricos de Kruskal-Wallis e Mann-Whitney (p < 0,05). RESULTADOS: As alterações foram mais intensas no grupo B1, com médias de escore da dissociação de fibras musculares de 2,16 ± 0,14, infiltrado neutrofílico de 2,05 ± 0,10 e expressão da caspase-3 na área perivascular de 4,30 ± 0,79; e menos intensas no grupo A3, com respectivas médias de 0,76 ± 0,16, 0,92 ± 0,10 e 0,67 ± 0,15 (p < 0,05). A caspase-3 mostrou-se mais expressiva no grupo B1 na área perivascular, com média de 4,30 ± 0,79, em comparação com o grupo B1 na área perinuclear, com média de 0,91 ± 0,32 (p < 0,05). CONCLUSÕES: As lesões são mais intensas quando o tempo de observação é maior após a reperfusão, e a pentoxifilina atenua essas lesões, sobretudo quando usada no início das fases de isquemia e de reperfusão.

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.

Nonmicrosurgical reconstruction of the auricle after traumatic amputation due to human bite

Background

Traumatic auricular amputation due to human bite is not a common event. Nonetheless, it constitutes a difficult challenge for the reconstructive surgeon. Microsurgery can be performed in some cases, but most microsurgical techniques are complex and their use can only be advocated in specialized centers. Replantation of a severed ear without microsurgery can be a safe alternative as long as a proper technique is selected.

Methods

We present two cases, one of a partial and one of a total traumatic auricular amputation, both caused by human bites, that were successfully managed in our Department. The technique of ear reattachment as a composite graft, with partial burial of the amputated part in the retroauricular region, as first described by Baudet, was followed in both cases.

Results and discussion

The prementioned technique is described in detail, along with the postoperative management and outcome of the patients. In addition, a brief review of the international literature regarding ear replantation is performed.

Conclusion

The Baudet technique has been used successfully in two cases of traumatic ear amputation due to human bites. It is a simple technique, without the need for microsurgery, and produces excellent aesthetic results, while preserving all neighboring tissues in case of failure with subsequent need for another operation.

Suppression of hypercholesterolemic atherosclerosis by pentoxifylline and its mechanism

Reactive oxygen species (ROS) have been implicated in the development of hypercholesterolemic atherosclerosis. Hypercholesterolemia increases the levels of platelet activating factor (PAF) and cytokines which are known to stimulate granulocytes and endothelial cells to produce ROS. Pentoxifylline (PTX) is an inhibitor of cytokines and PAF and would reduce the generation of ROS by granulocytes and endothelial cells. PTX therefore would be expected to reduce the development of hypercholesterolemic atherosclerosis. New Zealand white female rabbits were assigned to four groups: Group I (n=12), control; Group II (n=5), PTX control (40 mg/kg body weight daily orally); Group III (n=13), 0.5% cholesterol; Group IV (n=9), 0.5% cholesterol+PTX (40 mg/kg body weight daily orally). Blood samples were collected before (0 time) and after 1 and 2 months on experimental diets for measurement of serum triglycerides (TG), total cholesterol (TC), LDL-C, HDL-C and serum malondialdehyde (MDA), a lipid peroxidation product. At the end of 2 months the aorta was removed for measurement of atherosclerotic plaques, MDA, and aortic tissue chemiluminescence (Ao-CL), a marker for antioxidant reserve. Rabbits in Group III developed atherosclerosis (56.61+/-6.90% of the intimal surface of aorta was covered with atherosclerotic plaques) which was associated with an increase in the serum TG, TC, LDL-C, HDL-C, TC/HDL-C, MDA and aortic MDA and antioxidant reserve. PTX reduced the development of atherosclerosis by 38.1% and this was associated with decreases in serum MDA by 32%, aortic MDA by 37%, and antioxidant reserve by 17.3% without changes in the serum lipids. These results suggest that ROS generated during hypercholesterolemia via cytokines and PAF may in part contribute to the development of hypercholesterolemic atherosclerosis and that suppression of production and activity of cytokines and PAF may reduce the development of hypercholesterolemic atherosclerosis.

The ILAILL study: iloprost as adjuvant to surgery for acute ischemia of lower limbs: a randomized, placebo-controlled, double-blind study by the italian society for vascular and endovascular surgery

SUMMARY BACKGROUND DATA

High rate of complications has been reported following revascularization for acute limb ischemia (ALI). No adjuvant pharmacologic treatment, apart from anticoagulation and standard perioperative care, has been shown clinically effective.

OBJECTIVE

Aim of this study was to evaluate the effects of the prostacyclin analog iloprost as adjuvant to surgery for ALI.

METHODS

A total of 300 patients were randomly assigned to receive perioperative iloprost (intra-arterial, intraoperative bolus of 3000 ng, plus intravenous infusion of 0.5-2.0 ng/kg/min for 6 hours/day for 4-7 days following surgery), or placebo. The primary endpoint was the combined incidence of death and amputation at 3-month follow-up. Secondary endpoints were the incidence of each single major complication, total event rate, symptomatology, and tolerability.

RESULTS

The combined incidence of death and amputation was 19.9% in the placebo and 14.1% in the iloprost group (relative risk, 1.56; 95% confidence interval, 0.89-2.75, P = 0.12, Cox regression analysis). A statistically significant lower mortality (4.7%) was reported in patients receiving iloprost, compared with controls (10.6%; relative risk, 2.61; 95% confidence interval, 1.07-6.37, P = 0.03). The overall incidence of fatal plus major cardiovascular events was 33.1% and 22.8% in placebo and iloprost groups, respectively (relative risk, 1.61; 95% confidence interval, 1.04-2.49, P = 0.03). No serious adverse reactions occurred after iloprost administration, nor differences in the incidence of bleeding or hypotension between treatment groups.

CONCLUSIONS

Although at lower levels than previously reported, our results confirm the severity of ALI. Iloprost as adjuvant to surgery significantly reduced mortality and overall major event rate. Further data are needed to support this finding, and to face a still open medical issue.

Kupffer cell-dependent TNF-alpha signaling mediates injury in the arterialized small-for-size liver transplantation in the mouse

Implantation of small liver grafts causes liver injury and defective regeneration leading to graft failure. We investigated whether Kupffer cell-dependent TNF-alpha signaling contributes to this poor outcome. Partial 30% liver transplantation was performed in C57BL/6 wild-type mice (control group), and in three groups with down-regulation of the TNF-alpha pathway: (i) TNF receptor 1 knockout [TNFR-1(-/-)] mice, and mice pretreated with (ii) gadolinium chloride or (iii) pentoxifylline (PTX). Fifty-percent partial liver transplantation, a model associated with full recovery, and transplantation in IL-6 knockout [IL-6(-/-)] mice were performed in some experiments. Graft injury, regeneration, portal flow, liver microcirculation, leukocyte adhesion, and animal survival were assessed. Animal survival rates were 14% in the control group vs. 43% in the gadolinium chloride group, 57% for the TNFR-1(-/-) group, and 86% in the PTX group (P < 0.001). Markers of liver injury were reduced in all treated groups when compared with controls. Each treated group disclosed better portal flow and sinusoid perfusion, decreased leukocyte adherence, particularly in the PTX group. Liver regeneration occurred only in the treated groups. IL-6 and IL-10 levels were dramatically up-regulated (50x) in the PTX group, and at lower levels in other experimental groups. The protective effect of PTX was lost in IL-6(-/-) mice and protection was restored by a single dose of r-IL-6. In conclusion, interruption of TNF-alpha signaling or depletion of Kupffer cells improves survival after 30% liver transplantation, reduces liver injury, and enhances regeneration. The superior effects of PTX are mediated by IL-6.

Anesthésie–réanimation d’un patient en ischémie aiguë des membres inférieurs

OBJECTIVES

To appreciate the severity of a patient with acute limb ischaemia, to know how to manage these patients during the perioperative period.

DATA SOURCES

References were obtained from PubMed data bank (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) using the following keywords: acute limb, ischaemia, prognosis, complications, rhabdomyolysis, hyperkalaemia, compartment syndrome, fasciotomy.

DATA SYNTHESIS

Ischaemia of the lower limbs is a medico-surgical emergency. The ischaemia implies a decrease of cellular energetic stocks and an increase in intracellular calcium. During reperfusion, the calcium paradox is exacerbated and ROS formation produces membrane damage. Tissue oedema and a local and general inflammatory syndrome occur. Clinical symptoms of acute ischaemia include pallor, pulselessness, decrease of temperature and pain. Occurrence of neurological symptoms is a sign of severity. Prognosis of patients relates directly to preexisting collateral circulation, aetiology of the occlusion (thrombosis vs embolus), duration of ischaemia, topography of the occlusion (severity of proximal occlusions as the acute aortic occlusion), and co-morbidity (renal failure, heart failure). The temperature of the ischaemic limb, quality of the downstream circulation, extension of the thrombus, arterial pressure and association to a venous thrombosis are other prognostic factors of lower limb ischaemia. The first treatment to be initiated is high doses of heparin. Once the diagnosis is made, the number of preoperative tests will be as small as possible because of the urgency of revascularization. Arteriography will be performed only when really needed and when its realization will not delay revascularization and will not alter the patient's prognosis. Where general anesthesia is required, the choice of anaesthetic agents will be based on their haemodynamic stability. During severe acute limb ischaemia, monitoring of invasive pressure is recommended, as well as regular dosages of potassium, arterial gases and CPK. Preoperatively in case of severe ischaemia, (proximal occlusion lasting more than 6 hours), preventive treatment, including controlled reperfusion with heparinized serum is indicated. Surveillance and prevention of a rhabdomyolysis and renal failure are imperative. Immediately after reperfusion, a dosage of potassium must be performed; moreover that hyperkalaemia is favoured by acidosis or renal failure. Postoperative haemodialysis is performed in case of hyperkalaemia or renal failure. Occurrence of compartment syndrome has to be checked and fasciotomy must be performed in case of a doubt on the microcirculation integrity.

The Pathophysiology of Skeletal Muscle Ischemia and the Reperfusion Syndrome: A Review

There are two components to the reperfusion syndrome, which follows extremity ischemia. The local response, which follows reperfusion. consists of limb swelling with its potential for aggravating tissue injury and the systemic response, which results in multiple organ failure and death. It is apparent that skeletal muscle is the predominant tissue in the limb but also the tissue that is most vulnerable to ischemia. Physiological and anatomical studies show that irreversible muscle cell damage starts after 3 h of ischemia and is nearly complete at 6 h.

These muscle changes are paralleled by progressive microvascular damage. Microvascular changes appear to follow rather than precede skeletal muscle damage as the tolerance of capillaries to ischemia vary with the tissue being reperfused. The more severe the cellular damage the greater the microvascular changes and with death of tissue microvascular flow ceases within a few hours—the no reflow phenomenon. At this point tissue swelling ceases.

The inflammatory responses following reperfusion varies greatly. When muscle tissue death is uniform, as would follow tourniquet ischemia or limb replantation, little inflammatory response results. In most instances of reperfusion, which follows thrombotic or embolic occlusion, there will be a variable degree of ischemic damage in the zone where collateral blood flow is possible. The extent of this region will determine the magnitude of the inflammatory response, whether local or systemic. Only in this region will therapy be of any benefit, whether fasciotomy to prevent pressure occlusion of the microcirculation, or anticoagulation to prevent further microvascular thrombosis. Since many of the inflammatory mediators are generated by the act of clotting, anticoagulation will have additional benefit by decreasing the inflammatory response. In instances in which the process involves the bulk of the lower extremity, amputation rather than attempts at revascularization may be the most prudent course to prevent the toxic product in the ischemic limb from entering the systemic circulation.

Allopurinol plus pentoxifilline in hepatic ischaemia/reperfusion injury

OBJECTIVES

Ischaemia/reperfusion injury of the liver is the major cause of liver dysfunction and cellular death in transplantation and in liver resection with hepatic pedicle clamping. Many agents are used to prevent this phenomenon, which occurs following interaction of different mediators during both ischaemia and reperfusion. In this study, we aimed to assess the effects of allopurinol, a xanthine oxidase inhibitor, and pentoxifilline, on liver ischaemia/reperfusion injury when used together and to compare these with the effects of using these agents singly.

METHODS

Thirty-two rats were divided into four groups consisting of eight rats: Group C, control; Group P, pentoxifilline; Group A, allopurinol; and Group PA, pentoxifilline + allopurinol. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) levels were measured before hepatic pedicle clamping, on the 45th minute of ischaemia and 15 and 45 minutes after reperfusion. Group P rats were injected with 50 mg/kg pentoxifilline, Group A rats 50 mg/kg allopurinol and Group PA rats were injected with both agents 15 minutes before hepatic pedicle clamping.

RESULTS

Ischaemia/reperfusion injury was produced by hepatic pedicle clamping, as demonstrated by AST, ALT and LDH increase. Injury prevention occurred in Groups P, A and PA. No significantly different (better) prevention was provided by giving allopurinol plus pentoxifilline to the rats. Furthermore, no difference was observed between the allopurinol and pentoxifilline injected groups in terms of preventing ischaemia/reperfusion injury.

CONCLUSIONS

Pretreatment with allopurinol or pentoxifilline resulted in significantly lower hepatic enzyme elevation than that in controls in the rat liver ischaemia/reperfusion model. Using both agents does not provide better protection than using either agent alone.

Pentoxifylline attenuates hypoxic-ischemic brain injury in immature rats

Inflammatory mediators are implicated in the pathogenesis of ischemic injury in immature brain. The phosphodiesterase inhibitor pentoxifylline inhibits production of tumor necrosis factor-alpha and platelet-activating factor. We hypothesized that pentoxifylline treatment would attenuate hypoxic-ischemic brain injury in immature rats. Seven-day-old rats (n = 79) underwent right carotid ligation, followed by hypoxia (FiO2 = 0.08). Rats received pentoxifylline immediately before and again after hypoxia (two doses, 25-150 mg/kg/dose, n = 34), or vehicle (n = 27). In separate experiments, rats received pentoxifylline treatment (40 mg/kg/dose, n = 8), or vehicle (n = 10) immediately and again 3 h after hypoxia-ischemia. Severity of injury was assessed 5 d later by visual evaluation of ipsilateral hemisphere infarction and by measurement of bilateral hemispheric cross-sectional areas. Pentoxifylline pretreatment reduced the incidence of liquefactive cerebral infarction, from 75% in controls to 10% with pentoxifylline, 40 mg/kg/dose (p<0.001, chi2 trend test). Quantification of hemispheric areas confirmed these findings. In contrast, posthypoxic-ischemic treatment with pentoxifylline resulted in only a modest reduction in cortical damage, without an overall reduction in incidence of infarction. Phosphodiesterase inhibition may be an effective strategy to use to decrease the severity of neonatal hypoxic-ischemic brain injury. Pretreatment regimens could be clinically relevant in settings in which an increased risk of cerebral ischemia can be anticipated, such as in infants undergoing surgery to correct congenital heart disease.

Tumor necrosis factor-a attenuates N-methyl-D-aspartate-mediated neurotoxicity in neonatal rat hippocampus

Tumor necrosis factor-a TNFa. has been implicated in the pathophysiology of acute neonatal brain injury. We hypothesized that acute brain injury would induce TNFa expression and that exogenous TNFa would influence the severity of N-methyl-D-aspartate-induced tissue damage. We performed two complementary groups of experiments to evaluate the potential role s. of TNFa in a neonatal rodent model of excitotoxic injury, elicited by intracerebral injection of N-methyl-D-aspartate. We used immunohistochemistry and ELISA to evaluate N-methyl-D-aspartate-induced changes in TNFa expression, and we co-injected TNFa with N-methyl-D-aspartate, to evaluate the effect of this cytokine on the severity of tissue injury. Both intra-hippocampal and intra-striatal injection of N-methyl-D-aspartate 5 nmol. stimulated TNFa expression. Increased TNFa expression was detected 3-12 h after lesioning; TNFa was localized both in glial cells in the corpus callosum, and in cells with the morphology of interneurons in the ipsilateral hippocampus, striatum, cortex and thalamus. Intra-hippocampal or intra-striatal administration of TNFa 50 ng. alone did not elicit neuropathologic damage. In the hippocampus, when co-injected with N-methyl-D-aspartate 5 or 10 nmol., TNFa 50 ng. attenuated excitotoxic injury by 35%-57%, compared to controls co-injected with heat-treated TNFa. In contrast, in the striatum, co-injection of TNFa with N-methyl-D-aspartate had no effect on the severity of the ensuing damage. The data indicate that TNFa is rapidly produced in glial cells and neurons after an excitotoxic insult in the neonatal rat brain, and that administration of exogenous TNFa results in region-specific attenuation of excitotoxic damage. We speculate that endogenous TNFa may modulate the tissue response to excitotoxic injury in the developing brain.

Pentoxifylline attenuates reperfusion injury in skeletal muscle after partial ischemia

Leukocytes have been shown to contribute to ischemia-reperfusion injury in skeletal muscle. Pentoxifylline (PTXF), a xanthine-derived phosphodiesterase inhibitor, has received recent attention because of its action on leukocytes. To clarify the effects of PTXF in reperfusion injury, we measured the resting transmembrane potential difference (Em) and evaluated postcapillary venule microcirculation using intravital microscopy in rat skeletal muscle during ischemia and reperfusion. The infrarenal aorta was clamped for 90 min and then reperfused for 60 min. Persistent depolarization of the resting Em was observed in an ischemia-reperfusion (IR) group and was significantly repolarized in a PTXF group during the reperfusion period. The tissue water content was significantly reduced in the PTXF group, although no difference was noted in the tissue lactate content. Flowing erythrocyte velocity and wall shear rate in the PTXF group were significantly higher than in the IR group during the reperfusion period but without significant differences in vessel diameter and hemoglobin oxygenation. Blood flow measured by laser-Doppler flowmeter was also significantly improved in the PTXF group. Furthermore, the adherent leukocyte count was significantly reduced in the PTXF group during this same period. These results indicate that PTXF attenuated reperfusion-associated membrane injury and tissue edema and that PTXF suppressed leukocyte adhesion and improved hindlimb blood flow during the reperfusion period.

Effect of pentoxifylline on hepatic ischemia and reperfusion injury

BACKGROUND

Although pentoxifylline has been shown to improve tissue oxygenation and restore hepatocellular function after hemorrhagic shock, its effect on hepatic ischemia and reperfusion injury has not been fully clarified. The purpose of this study was to determine whether pentoxifylline exerted beneficial effects on liver histopathologic changes and enzymatic release caused by ischemia and reperfusion.

METHODS

Warm, reversible hepatic ischemia/reperfusion injury was induced in four groups of pigs. Preoperative oral (24 mg/kg or 50 mg/kg) or intraoperative intravenous (50 mg/kg) pentoxifylline was administered. Control animals received intravenous normal saline solution.

RESULTS

Untreated control animals exhibited significant liver damage expressed by hepatic histopathologic changes and high plasma levels of aminotransferases. Decreased animal survival was seen in the untreated group. All treated animals survived. Pentoxifylline given orally did not improve histopathologic changes or enzyme release. Intravenous administration caused significant amelioration of liver tissue damage, marked reduction of aspartate aminotransferase levels, and mild attenuation of alanine aminotransferase levels, as compared with control.

CONCLUSIONS

This study indicates that intraoperative, intravenous pentoxifylline reduces hepatic injury after warm ischemia and reperfusion.