Sildenafil attenuates hepatocellular injury after liver ischemia reperfusion in rats: a preliminary study

Protective effect of irbesartan against hepatic ischemia-reperfusion injury in rats: role of ERK, STAT3, and PPAR-γ inflammatory pathways in rats

This study aimed to elucidate the possible hepatocellular protective role of irbesartan during hepatic ischemia-reperfusion injury (HIRI) and the probable underlying mechanisms. Wistar rats were allocated into four groups: sham; HIRI (control); irbesartan (50 mg/kg) + HIRI; irbesartan (100 mg/kg) + HIRI; irbesartan + GW9662 (1 mg/kg, i.p.) + HIRI. Rats pretreated orally with irbesartan or vehicle for 14 days underwent 45-min hepatic ischemia followed by 60-min reperfusion. Irbesartan preconditioning diminished alanine transaminase (ALT) and aspartate transaminase (AST) serum levels, and reduced extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3). Irbesartan decreased proapoptotic BAX (bcl-2-like protein 4), increased anti-apoptotic B-cell lymphoma 2 (BCL2) hepatic content, and thereby reduced BAX/BCL2 ratio. Moreover, irbesartan preconditioning reduced autophagy-related proteins Beclin1 and LC3 II, and elevated p62 (protein responsible for autophagosome degradation). It elevated proliferator-activated receptor γ (PPAR-γ), and reduced tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) hepatic gene expression. Also, hepatic protein expressions of nuclear factor kappa-B p65 (NF-κB p65) and caspase-3 were lessoned by irbesartan pretreatment in HIRI rats. However, GW9662 abrogated irbesartan's effect on HIRI. The protective effect of irbesartan on HIRI may be mediated by alleviation of ERK, STAT3, and PPAR-γ inflammatory pathways, exerting anti-apoptotic and anti-autophagic effects in HIRI in rats.

Blockade of phosphodiesterase 5 by sildenafil reduces tumor growth and potentiates tumor-killing ability of cisplatin in vivo against T cell lymphoma: Implication of modulated apoptosis, reactive oxygen species homeostasis, glucose metabolism, and pH regulation

In the past years, PDE5 has emerged as a promising therapeutic target for many cancers due to its highly upregulated expression. Interestingly, a recent in vitro study by our group has shown the antitumor and chemopotentiating action of sildenafil against T cell lymphoma. Our study showed that lower doses of sildenafil (50 μM) and cisplatin (0.5 μg/mL) exhibited 4% and 23% cytotoxicity against HuT78 cells, respectively, which was dramatically increased up to 50% when treated with both. Hence, the present study was designed to evaluate the antitumor and chemo-potentiating action of sildenafil in a murine model of T cell lymphoma (popularly called as Dalton's lymphoma [DL]). In the present study, DL-bearing mice were administered with vehicle (PBS), sildenafil (5 mg/kg bw), cisplatin (5 mg/kg bw), and sildenafil and cisplatin followed by evaluation of their impact on tumor growth by analyzing various parameters. The apoptosis was assessed by Wright-Giemsa, annexin-V, and DAPI staining. Reactive oxygen species (ROS) level was examined through DCFDA staining. The expression of genes and proteins were estimated by RT-PCR and Western blotting, respectively. The experimental findings of the study demonstrate for the first time that sildenafil inhibits tumor growth and potentiates tumor inhibitory ability of cisplatin by altering apoptosis, glycolysis, ROS homeostasis, and pH regulation in T cell lymphoma-carrying host. In addition, our investigation also showed amelioration of tumor-induced liver and kidney damage by sildenafil. Overall, the experimental data of our study strongly advocate the use and repurposing of SDF in designing promising chemotherapeutic regimens against malignancies of T cells.

A new insight into the hepatoprotective effect of sildenafil: The role of H2S

High-calorie diet, alcohol, and multiple drug use increase reactive oxygen species (ROS) and cause liver damage. ROS are crucial in the initiation/progression of liver diseases. Antioxidants have beneficial effects but produce clinically complex results. The hydrogen sulfide (H2S) pathway is considered a promising therapeutic target since it plays role in the pathogenesis/treatment of liver diseases. Sildenafil exerts antioxidant and hepatoprotective effects by increasing specific antioxidants such as superoxide dismutase, glutathione peroxidase, and regulating the Keap1/Nrf2 pathway which are common mechanisms underlying the effects of H2S. We aimed to determine if H2S has a role in the hepatoprotective and antioxidant effects of sildenafil. The effect of sildenafil on endogenous H2S production was elucidated with an H2S microsensor in the presence/absence of pyrogallol-induced oxidative stress and H2S synthesis inhibitor aminoxyacetic acid (AOAA) in the liver. The relation between the antioxidant effect of sildenafil and H2S was determined by luminol and lucigenin chemiluminescence. Sildenafil increased L-cysteine-induced H2S synthesis in the healthy liver and prevented the pyrogallol-induced reduction in H2S production. Sildenafil decreased the ROS production induced by pyrogallol and its protective effect was inhibited by AOAA. These results reveal that H2S is a new pharmacological mechanism of action of sildenafil on the liver. Therefore, sildenafil can be a potential therapeutic agent in treating many liver diseases in which H2S bioavailability is impaired. Additionally, the hepatoprotective effect of sildenafil by increasing endogenous H2S synthesis advances our knowledge in terms of developing H2S-targeting molecules.

Experimental isolation and preservation of solid organs before transplantation: effects of pretreatment using four different molecules

OBJECTIVES

In transplantation surgery, the ischaemic organ and reperfusion impairment after cold storage remains a considerable risk factor for impaired function and potential failure of the grafted organ. Substantial logistical efforts have been undertaken to reduce the cold ischaemic time because the demand for available transplant organs and the periods of cold ischaemia are increasing.

METHODS

Four molecules were investigated (erythropoietin, sildenafil, lazaroid [U74389G], octreotide) in individual intravenous infusions 1 hour before the organ was harvested. This study was performed in 30 healthy landrace/large-white pigs (male; >10 weeks old; average weight, 22 ± 2 kg) in groups of six. The organs were studied at harvest, and at 8 and 24 hours post-harvest.

RESULTS

The lazaroid molecule increased malondialdehyde (MDA) levels in the liver and pancreas at 8 hours. Hepatic lazaroid molecules improved liver histology at 8 and 24 hours. For kidneys, erythropoietin had a positive effect at 24 hours post-harvest. For the pancreas, octreotide showed better performance. In the lungs, there was less interstitial oedema with erythropoietin and lazaroid compared with the control group at 8 hours post-harvest.

CONCLUSION

All molecules had a positive effect and decreased ischaemia/reperfusion graft injury. Thus, pretreatment before organ harvest has a beneficial role.

Targeting autophagy to modulate hepatic ischemia/reperfusion injury: A comparative study between octreotide and melatonin as autophagy modulators through AMPK/PI3K/AKT/mTOR/ULK1 and Keap1/Nrf2 signaling pathways in rats

Hepatic ischemia-reperfusion (HIR) injury is a common pathophysiological process in many clinical settings. This study was designed to compare the protective role of octreotide (somatostatin analogue, OCT) and melatonin (N-acetyl-5-methoxytryptamine, MLT) through the modulation of autophagy against HIR injury in rats. Male albino rats were divided into sham, HIR, OCT at three doses (50, 75, and 100 μg/kg), MLT, MLT + OCT75, compound C (AMPK inhibitor, CC), and CC + OCT75 groups. Ischemia was induced for 30 min followed by 24 h reperfusion. Biochemical, histopathological, immunohistochemical, lipid peroxidation, ELISA, qPCR, and western blot techniques were performed in our study. Liver autophagy was restored by OCT at doses (50 or 75 μg/kg) as indicated by elevating the expressions of Beclin-1, ATG7, and LC3 accompanied by the reduction of p62 expression through induction of AMPK/S317-ULK1 and inhibition of PI3K/AKT/mTOR/S757-ULK1 signaling pathways. As well, OCT maintained the integrity of the Keap1-Nrf2 system for the normal hepatic functions via controlling the Keap1 turnover through autophagy in a p62-dependent manner, resulting in upholding a series of anti-oxidant and anti-inflammatory cascades. These effects were abolished by compound C. On the other hand, MLT showed a decrease in the autophagy markers via inhibiting AMPK/pS317-ULK1 and activating PI3K/AKT/mTOR/pS757-ULK1 pathways. Autophagy inhibition with MLT markedly reversed the hepatoprotective effects of OCT75 after HIR injury. Finally, our results proved for the first time that OCT75 was more effective than MLT as it was sufficient to induce protective autophagy in our HIR model, which led to the induction of Nrf2-dependent AMPK/autophagy pathways.

Sildenafil beyond erectile dysfunction and pulmonary arterial hypertension: Thinking about new indications

Sildenafil, approved two decades ago, is the inhibitor of phosphodiesterase 5 (PDE5). First of all, it was designated for angina pectoris, but soon it showed a wonderful efficacy in erectile dysfunction (ED) and then pulmonary arterial hypertension (PAH). Due to the distribution of phosphodiesterase (PDE) in almost all organs, maybe it effects other diseases. Hence, a great number of investigations began to understand the role of PDEi in different organs. Preliminary research on sildenafil in cell culture and animal models has yielded promising results. Soon, a greater number of animal researches and clinical trials joined them. The results disclosed sildenafil can have beneficial effects in each organ such as heart, liver, kidney, brain, and intestines. Furthermore, it has significantly improved the prognosis of organ ischemia in various animal models. Clinical trials in several diseases, such as recurrent spontaneous miscarriage, fatty liver disease, bronchopulmonary dysplasia (BPD), heart failure, and premature ejaculation (PE) brought promising results. Although some clinical trials are available on the effects of sildenafil on various diseases, further studies on humans are needed to consolidate the ultimate effects of sildenafil. The aim of this review was to describe the effects of sildenafil on each organ and explain its mechanisms of action. Further, other PDE inhibitors such as tadalafil and vardenafil have been briefly discussed in parts of this review.

Octreotide and melatonin alleviate inflammasome-induced pyroptosis through inhibition of TLR4-NF-κB-NLRP3 pathway in hepatic ischemia/reperfusion injury

BACKGROUND AND AIM

The Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB)/NLRP3 inflammasome signaling pathway is essential in the pathogenesis of hepatic ischemia/ reperfusion (HIR) injury. Pyroptosis is a proinflammatory programmed cell death that is related to several diseases. Thus, the purpose of this study was to examine whether pretreatment with octreotide (somatostatin analogue, OCT) at different doses or OCT at 75μg/kg combined with melatonin (N-acetyl-5-methoxytryptamine, MLT) can alleviate HIR injury via targeting NLRP3 inflammasome-induced pyroptosis in a TLR4/MyD88/NF-κB dependent manner.

METHODS

Rats were randomized into sham, HIR, OCT (50, 75, and 100 µg/kg), MLT, and MLT + OCT75 groups. Ischemia was induced via occlusion of the portal triad for 30 min followed by 24 h reperfusion.

RESULTS

OCT pretreatment at doses (50 or 75 μg/kg), MLT alone, and MLT + OCT75 significantly ameliorated the biochemical with histopathological changes, oxidative stress, inflammation, apoptosis, then augmented anti-oxidant and anti-apoptotic markers through downregulation of HMGB1, TLR4, MyD88, TRAF-6, p-IκBα (S32), p-NF-κBp65 (S536), NLRP3, ASC, caspase-1(p20), and GSDMD-N expressions compared with HIR group.

CONCLUSION

OCT at doses (50 or 75 µg/kg) showed for the first time a hepatoprotective effect against HIR injury via inhibiting TLR4-NLRP3-mediated pyroptosis in rats. As well, OCT75 was more effective than OCT50 or MLT alone, and its effect was not enhanced after the addition of MLT, through downregulation of TLR4/MyD88/NF-κB/NLRP3 inflammasome pathway.

Sildenafil ameliorates Alzheimer disease via the modulation of vascular endothelial growth factor and vascular cell adhesion molecule-1 in rats

Alzheimer disease (AD) is a chronic neurodegenerative disease with multi-pathways pathogenesis. Sildenafil is a selective phosphodiesterase-5 inhibitor with a potential benefit in the treatment of AD. This study investigated the possible mechanisms underlying the effect of sildenafil in AD with emphasis on vascular endothelial growth factor (VEGF), and vascular cell adhesion molecule-1 (VCAM-1). Twenty-four adult male rats were classified into four groups; control group: received vehicles, sildenafil-control: received sildenafil (15 mg/kg/day, p.o.), AD group received Aluminum (25 mg/kg/day, p.o.), AD-treated group: received sildenafil (15 mg/kg/day, p.o.) for 6 weeks. AD was assessed by memory performance test and confirmed by histopathological examination and immunostaining of, neurogenesis marker nestin and α-synuclein. The levels of VEGF-A, VCAM-1, oxidative stress markers and TNF-α in brain tissue were evaluated. AD rats showed histopathological evidences of AD; along with increased latency time in the memory test. There was a decrease in VEGF-A, and an increase in VCAM-1, TNF-α, and oxidative stress markers. Immunohistochemical study showed a significant increase in α-synuclein and a significant decrease in nestin expressions in brain tissues. Sildenafil administration ameliorated the histopathological changes and decreased latency time. Such effect was associated with a decrease in VCAM-1, TNF-α and oxidative stress as well as an increase in VEGF-A. Sildenafil caused a significant increase in nestin and a decrease in α-synuclein immunostaining. These findings suggested a protective effect of sildenafil via modulation of VEGF-A, and VCAM-1.

Riluzole protects against skeletal muscle ischaemia-reperfusion injury in a porcine model

INTRODUCTION

Skeletal muscle ischaemia-reperfusion injury (IRI) can be a life threatening condition. It is relevant to various aspects of the management of trauma and surgical patients. Currently there lacks a pharmacological agent that can be used to dampen the effects of IRI. Riluzole has been shown to reduce the effects of IRI on various organ systems, but there have yet to be any studies on the effects in IRI of skeletal muscle. Our aim was to investigate the effects of Riluzole on IRI in the skeletal muscle of pigs.

METHODS

Twenty-two pigs were randomly divided into groups. Riluzole was administered before ligation of the femoral artery to produce ischaemia in the tibialis anterior muscle in the experimental group but not the control group. The microscopic appearance of muscles were recorded, a TUNEL assay was used to identify DNA damage and glutathione levels were measured.

RESULTS

In the Riluzole group, muscle fibres appeared less wavy and less oedematous compared to the control group. The Riluzole group also had less evidence of DNA fragmentation on the TUNEL assay. The glutathione levels in the Riluzole group were also significantly greater than the control group.

DISCUSSION

Our findings suggest that Riluzole can potentially reduce the effects of IRI on skeletal muscle. This is potentially due to the ability of Riluzole to block sodium channels, decreasing action potentials and therefore glutamate release. It also acts to decrease intracellular calcium levels, which prevents apoptosis. Riluzole is a promising drug for the prevention of IRI in skeletal muscle, but further research is required.

Renoprotective effect of local sildenafil administration in renal ischaemia-reperfusion injury: A randomised controlled canine study

Objectives: To design a new canine model to assess the renoprotective effect of local sildenafil administration, as the renoprotective effect of systemic sildenafil administration in renal ischaemia-reperfusion (IR) injury in animal models has been shown but its local effects have not been established to date. Materials and methods: In all, 120 dogs were assigned to five groups: sham, oral control (OC) group (right nephrectomy + left renal ischaemia for 60 min), oral sildenafil (OS) group (oral sildenafil 1 mg/kg, 60 min before ischaemia), local control (LC) group (local renal perfusion with saline and heparin for 5 min) and local sildenafil (LS) group (perfusion with sildenafil 0.5 mg/kg). Renal functions, histopathological changes, expression of caspase-3, nuclear factor erythroid 2-related factor 2 (Nrf2), inflammatory cytokines (intracellular adhesion molecule 1, tumour necrosis factor α and interleukin 1β) and endothelial nitric oxide synthase (eNOS) in renal tissues were assessed in all groups at 1, 3, 7 and 14 days. Results: There were significant improvements in renal functions and cortical and medullary damage scores in the sildenafil-treated groups compared to their control groups (P < 0.05). Also, the LS group showed significantly better improvement of renal functions and cortical and medullary damage scores than the OS group (P < 0.05). Moreover, sildenafil significantly decreased the expression of caspase-3 and inflammatory cytokines and increased the expression of Nrf2 and eNOS in renal tissue, which were statistically significant in the LS group. Conclusion: LS has a greater renoprotective effect against renal IR injury than systemic administration via anti-inflammatory, antioxidant and anti-apoptotic pathways. Abbreviations: BUN: blood urea nitrogen; Ct: cycle threshold; eNOS: endothelial nitric oxide synthase; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; H&E: haematoxylin and eosin; IL-1β: interleukin 1β; NO: nitric oxide; Nrf2: nuclear factor erythroid 2-related factor 2; OC: oral control; OS: oral sildenafil; LC: local control; LS: local sildenafil.

Effect of the Phosphodiesterase 5 Inhibitor Sildenafil on Ischemia-Reperfusion-Induced Muscle Mitochondrial Dysfunction and Oxidative Stress

Lower-limb ischemia-reperfusion (IR) is frequent and associated with significant morbidity and mortality. Phosphodiesterase 5 inhibitors demonstrated antioxidant and beneficial effects in several organs submitted to IR, but their effects on muscle mitochondrial functions after lower-limb IR are unknown. Unilateral hindlimb IR (2 h tourniquet followed by 2 h reperfusion) without or with sildenafil (1mg/kg ip 30 minutes before ischemia) was performed in 18 mice. Maximal oxidative capacity (V_Max), relative contribution of the mitochondrial respiratory chain complexes, calcium retention capacity (CRC)—a marker of apoptosis—and reactive oxygen species (ROS) production were determined using high-resolution respirometry, spectrofluorometry, and electron paramagnetic resonance in gastrocnemius muscles from both hindlimbs. IR significantly reduced mitochondrial V_Max (from 11.79 ± 1.74 to 4.65 ± 1.11 pmol/s*mg wet weight (ww), p < 0.05, −50.2 ± 16.3%) and CRC (from 2.33 ± 0.41 to 0.84 ± 0.18 µmol/mg dry weight (dw), p < 0.05; −61.1 ± 6.8%). ROS tended to increase in the ischemic limb (+64.3 ± 31.9%, p = 0.08). Although tending to reduce IR-related ROS production (−42.4%), sildenafil failed to reduce muscle mitochondrial dysfunctions (−63.3 ± 9.2%, p < 0.001 and −55.2 ± 7.6% p < 0.01 for V_Max, and CRC, respectively). In conclusion, lower limb IR impaired skeletal muscle mitochondrial function, but, despite tending to reduce ROS production, pharmacological preconditioning with sildenafil did not show protective effects.

Vildagliptin Attenuates Hepatic Ischemia/Reperfusion Injury via the TLR4/NF-κB Signaling Pathway

The Toll-like receptor-4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway is vital in the pathogenesis of hepatic ischemia/reperfusion (HIR) injury. Dipeptidyl peptidase-4 (DPP4) inhibitors exert protective effects on IR injury of the kidney, heart, and lung; however, their effect on the liver is still unknown. Thus, the purpose of this study was to examine whether pretreatment with vildagliptin (Vilda), a DPP4 inhibitor, produces hepatic protection against IR injury and to investigate its influence on TLR4/NF-κB signaling in a rat model. Thirty male Wistar rats were divided into 3 groups: the sham group: subjected to a sham operation and received normal saline; the HIR group: subjected to HIR and received normal saline; and the Vilda + HIR group: subjected to HIR with pretreatment of 10 mg/kg/day Vilda for 10 days intraperitoneally. Hepatic ischemia lasted for 45 minutes followed by 3-hour reperfusion; then blood and liver samples were collected for biochemical and histopathological examination. The HIR group produced a significant increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA), nitric oxide (NO), and tumor necrosis factor alpha (TNF-α) levels and a significant reduction in the hepatic catalase level in comparison to the sham group. Moreover, a significant upregulation of gene and protein expressions of TLR4, NF-κB, and high-mobility group box-1 (HMGB1) along with caspase-3 protein expression was observed in the HIR group when compared with the sham group. Histopathological examination of the liver from the HIR group showed necrosis, sinusoidal congestion, hemorrhage, and hepatocyte degeneration. Administration of Vilda ameliorated the biochemical and histopathological changes caused by HIR. Vildagliptin showed for the first time a hepatoprotective effect in HIR injury through downregulation of TLR4/NF-κB/HMGB1 and caspase-3 hepatic expressions.

Olprinone protects the liver from ischemia–reperfusion injury through oxidative stress prevention and protein kinase Akt activation

Liver ischemia–reperfusion (IR) injury is inevitable in surgical procedures such as hepatic resection and liver transplantation. It represents a leading cause of liver graft dysfunction and primary nonfunction after transplantation. Phosphodiesterase (PDE) inhibitors are emerging as effective drugs able to reduce IR damage. The aim of this study was to investigate the effect of selective PDE-3 inhibitor olprinone (Olp) against liver IR injury. Male Wistar rats were subjected to 1 h of partial warm ischemia (70%) followed by 6 h of reperfusion. Before ischemia, rats were treated with saline (IR group), Olp (Olp group), or Olp with Akt inhibitor LY294002 (Olp plus LY group). After reperfusion, hepatic injury (transaminase activities), mitochondrial damage (glutamate dehydrogenase activity), oxidative stress (malondialdehyde and glutathione concentrations and catalase and superoxide dismutase activities), and protein kinase Akt activation were evaluated. Rat treatment with Olp reduced liver injury, prevented mitochondrial damage, decreased lipid peroxidation, and enhanced antioxidant enzymes. Also, Olp induced a significant activation in protein kinase Akt. Inhibition of Akt with LY294002 abolished all of the protective effects of Olp. In conclusion, Olp treatment may be an effective strategy in reducing liver IR injury through oxidative stress prevention and Akt activation.

The role of sildenafil in the development of transplant arteriosclerosis in rat aortic grafts

Chronic rejection (CR), which is characterized histologically by progressive graft arteriosclerosis, remains a significant barrier to the long-term survival of a graft. Sildenafil has been shown to protect vascular endothelial cells. In this study, we found that sildenafil significantly reduces the thickness of transplant vascular intima in a rat aortic transplant model. Moreover, sildenafil dramatically decreased the expression of transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF), and α-smooth muscle actin (α-SMA) in the grafted aortas and increased the concentrations of cyclic guanosine monophosphate (cGMP) and endothelial nitric oxide synthase (eNOS) in serum. Furthermore, the ratio of regulatory T (Treg) cells and the expression of FoxP3 were increased, and the ratio of Th17 cells was decreased in the sildenafil-treated group. These results demonstrate that sildenafil enhances nitric oxide (NO) signaling by increasing the availability of cGMP, leading to an increase in the ratio of Treg/Th17 cells to attenuate transplant arteriosclerosis in a rat aortic transplant model.

Sildenafil potentiates the antitumor activity of cisplatin by induction of apoptosis and inhibition of proliferation and angiogenesis

Sildenafil is the first phosphodiesterase-5 inhibitor used for the treatment of erectile dysfunction. However, recent studies have been suggesting an antitumor effect of sildenafil. The current study assessed the aforementioned activity of sildenafil in vivo and in vitro in solid-tumor-bearing mice and in a human cell line MCF-7, respectively. Moreover, we investigated the impact of sildenafil on cisplatin antitumor activity. The solid tumor was induced by inoculation of Ehrlich ascites carcinoma cells in female mice. The tumor-bearing mice were assigned randomly to control (saline), sildenafil (sildenafil 5 mg/kg/d, PO daily for 15 days), cisplatin (cisplatin 7.5 mg/kg, IP once on the 12th day of Ehrlich ascites carcinoma inoculation), and combination therapy (cisplatin and sildenafil) groups. The tumor volume was measured at the end of the treatment period along with the following parameters: angiogenin, vascular endothelial growth factor, tumor necrosis factor-α, Ki-67, caspase-3, DNA-flow cytometry analysis, and histopathological examination. The study results showed that sildenafil has significantly decreased the tumor volume by 30.4%, angiogenin and tumor necrosis factor-α contents, as well as vascular endothelial growth factor expression. Additionally, caspase-3 level significantly increased with sildenafil treatment, whereas Ki-67 expression failed to show any significant changes. Furthermore, the cell cycle analysis revealed that sildenafil was capable of improving the category of tumor activity from moderate to low proliferative. Sildenafil induced necrosis in the tumor. Moreover, the drug of interest showed cytotoxic activity against MCF-7 in vitro as well as potentiated cisplatin antitumor activity in vivo and in vitro. These findings shed light on the antitumor activity of sildenafil and its possible impact on potentiating the antitumor effect of conventional chemotherapeutic agents such as cisplatin. These effects might be related to antiangiogenic, antiproliferative, and apoptotic activities of sildenafil.

Intraperitoneal administration of apigenin in liver ischemia/reperfusion injury protective effects

BACKGROUND/AIMS

Hepatic injury caused by ischemia/reperfusion (I/R) is a clinical problem associated with major liver surgery. Among other flavonoids, apigenin has shown a promising effect on I/R cases. In this study, we have investigated the effects of apigenin after liver I/R injury in rats.

MATERIALS AND METHODS

Forty eight rats were randomized into the following eight groups: (1) Control-sham group: rats subjected to the surgical procedure, except for liver I/R; (2) DMSO group: rats subjected to surgery, except for liver I/R given the apigenin solvent dimethyl-sulfoxide intraperitoneally; (3) C60 group; (4) C120 group; (5) C240 group: rats underwent liver ischemia for 45 min followed by reperfusion for 60 min, 120 min, and 240 min; (6) AP60 group; (7) AP120 group; (8) AP240 group: rats underwent liver ischemia for 45 min, and then given apigenin (5 mg) intraperitoneally followed by reperfusion for 60 min, 120 min, and 240 min. Reverse transcription polymerase chain reaction was performed on liver tissues to measure BCL-2/BAX expression, enzyme-linked immunosorbent assay to measure M30/M65 and ICAM-1. Immunohistochemistry was used to identify M30 biomarker in liver tissues.

STATISTICAL ANALYSIS

Quantitative variables were tested by Kolmogorov-Smirnov test, repeated measures analysis of variance/Friedman test. Gene levels were assessed by Student's t-test/Mann-Whitney U-test.

RESULTS

BCL-2 levels were significantly higher in I/R apigenin groups than in I/R control groups. BAX levels were lower in the AP240 group than in C240 group. Prolongation of reperfusion resulted in increased activation of M30. ICAM-1 levels were lower in the AP240 group than in C240 group.

CONCLUSIONS

Apigenin seems to inhibit the process of apoptosis and ameliorate the hepatic I/R injury.

Hypoxemic reperfusion of ischemic states: an alternative approach for the attenuation of oxidative stress mediated reperfusion injury

Ischemia and reperfusion (I/R) - induced injury has been described as one of the main factors that contribute to the observed morbidity and mortality in a variety of clinical entities, including myocardial infarction, ischemic stroke, cardiac arrest and trauma. An imbalance between oxygen demand and supply, within the organ beds during ischemia, results in profound tissue hypoxia. The subsequent abrupt oxygen re-entry upon reperfusion, may lead to a burst of oxidative aggression through production of reactive oxygen species by the primed cells. The predominant role of oxidative stress in the pathophysiology of I/R mediated injury, has been well established. A number of strategies that target the attenuation of the oxidative burst have been tested both in the experimental and the clinical setting. Despite these advances, I/R injury continues to be a major problem in everyday medical practice. The aim of this paper is to review the existing literature regarding an alternative approach, termed hypoxemic reperfusion, that has exhibited promising results in the attenuation of I/R injury, both in the experimental and the clinical setting. Further research to clarify its underlying mechanisms and to assess its efficacy in the clinical setting is warranted.

Molecular pathways in protecting the liver from ischaemia/reperfusion injury: a 2015 update

Ischaemia/reperfusion injury is an important cause of liver damage during surgical procedures such as hepatic resection and liver transplantation, and represents the main cause of graft dysfunction post-transplantation. Molecular processes occurring during hepatic ischaemia/reperfusion are diverse, and continuously include new and complex mechanisms. The present review aims to summarize the newest concepts and hypotheses regarding the pathophysiology of liver ischaemia/reperfusion, making clear distinction between situations of cold and warm ischaemia. Moreover, the most updated therapeutic strategies including pharmacological, genetic and surgical interventions, as well as some of the scientific controversies in the field are described.