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.

Metformin potentiates the chemotherapeutic effects of doxorubicin on 2-amino-1-methyl-6-phenylimidazo[4,5b] pyridine-induced Mammary Carcinoma in rats.

This study was carried out to evaluate the antitumor activity of Metformin (Met) and its impending utility to potentiate the chemotherapeutic action of doxorubicin on 2-amino-1-methyl-6-phenylimidazo[4,5b]pyridine (PhIP)-induced rat mammary carcinogenesis. Female Sprague -Dawley (SD) rats were divided into seven groups (n = 15 each). Mammary carcinogenesis was induced by the administration of PhIP at a dose of 75 mg/kg by gavage. Met treatment was 2 mg/ml in drinking water for 26 weeks started after the last PhIP dose. Doxorubicin (Dox) treatment started after one month of the last PhIP dose with a dose of 4 mg/kg, i.v. once per week for 4 weeks. Compared to the PhIP group, the latency period of tumors in the PhIP+Dox, PhIP+Met, and PhIP+Dox+Met groups were significantly increased and tumors' incidences and multiplicities were significantly reduced. By immunohistochemistry, carcinomas from the combination treatment groups showed a significant decrease in the labeling indexes (LI%) of cellular proliferation and CD44 compared to the PhIP group while LI% for ERα was significantly decreased in all combination treatment groups compared to the PhIP-administered group. Moreover, the quantitative mRNA expression of ERα was significantly decreased in mammary tumors from PhIP + Dox+Met combined group more than the PhIP + Dox group. However, mRNA expression of EGF was found significantly lower in all combination treatment groups compared to the PhIP group. These findings suggest that Metformin potentiate the antitumor efficacy of doxorubicin and had beneficial effects on PhIP-induced mammary carcinogenesis through the prevention of cellular proliferation and mRNA expression of ERα and EGF.

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.

Comparative effects of enalapril versus perindopril on serum levels of leptin and adiponectin in hypertensive patients.

Introduction: Abnormal adipokine levels affect blood pressure (BP) regulation. Hypo-adiponectinaemia and hyperleptinaemia were reported in hypertension, little is known about how antihypertensive therapy affects these alterations. This study aimed to evaluate the effects of perindopril versus enalapril on plasma adiponectin, tumour necrosis alpha (TNF-α) and leptin levels in hypertensive individuals.Methods: In the present study, we analysed the samples obtained from 93 treatment-naive, adult hypertensive patients, randomised to treatement with enalapril (10 mg/d, n = 31), perindopril (5 mg/d, n = 31), or maintained on life style modification (n = 31). Plasma levels of leptin, adiponectin, TNF-α and lipid profile were determined at baseline, and after 3 months.Results: Compared to subjects maintained on lifestyle modification (n = 31), enalapril or perindopril treatment was associated with a significant decrease in BP. Administration of perindopril or enalapril resulted in an increase in plasma adiponectin and a reduction in plasma leptin. No significant changes in lipid profile were observed after treatment.Conclusions: Our results indicate that perindopril is superior to enalapril when it comes to its effect on the human adipose-tissue-derived hormones. This suggests that angiotensin-converting enzyme inhibitors improves the adipokine profile, possibly allowing beneficial effects to hypertensive individuals.

Antifibrotic effect of diethylcarbamazine combined with hesperidin against ethanol induced liver fibrosis in rats.

Chronic alcohol consumption leads to extracellular matrix hyperplasia and liver fibrosis with a great role of hepatic stellate cell (HSC) activation in this process. The present study was designed to investigate the possible protective effects of diethylcarbamazine (DEC) (50mg/kg, acting as an anti-inflammatory drug, interferes with the arachidonic acid metabolism) when administrated in combination with hesperidin (HDN) (200mg/kg, a flavanone glycoside with potent antioxidant and anti-inflammatory activities) against alcoholic liver fibrosis in wistar rats compared to silymarin (Sil) (100mg/kg). Liver fibrosis was induced in rats using ethanol (EtOH) (1ml/100g/day, p.o.) twice a week for seven weeks. Then, tissue and blood samples were collected to assess the protective effect of DEC+HDN combination. Our results indicated that DEC when combined with HDN blunted EtOH-induced necroinflammation and elevation of liver injury parameters in serum. Besides, attenuated EtOH- induced liver fibrosis, as demonstrated by hepatic histopathology scoring and 4-hydroxyproline content. The mechanisms behind these beneficial effects of both DEC and HDN were also elucidated. These include (1) counteracting hepatic oxidative stress and augmenting hepatic antioxidants; (2) inhibiting the activation of NF-κB as indicated by preventing release of hepatic IL6; (3) preventing the activation of hepatic stellate cells (HSCs), as denoted by reducing a-smooth muscle actin (a-SMA) expression in the liver; and (4) inhibiting the fibrogenesis response of HSCs, as indicated by inhibiting serum transforming growth factor-b1 (TGF-b1). Our study indicates a novel hepatoprotective effect when DEC was co-administered with HDN against liver fibrosis.

Role of cysteinyl leukotriene receptor-1 antagonists in treatment of experimentally induced mammary tumor: does montelukast modulate antitumor and immunosuppressant effects of doxorubicin?

It has been reported that a leukotriene (LT)-D4 receptor (i.e. cysteinyl LT1 receptor; CysLT1R) has an important role in carcinogenesis. The current study was carried out to assess the possible antitumor effects of montelukast (MON), a CysLT1R antagonist, in a mouse mammary carcinoma model, that is, a solid Ehrlich carcinoma (SEC). Effects of MON on tumor-induced immune dysfunction and the possibility that MON may modulate the antitumor and immunomodulatory effects of doxorubicin (DOX) were also studied. The effects in tumor-bearing hosts of several dosings with MON (10 mg/kg, per os), with and without the added presence of DOX (2 mg/kg, intraperitoneal), were investigated in vivo; end points evaluated included assessment of tumor volume, splenic lymphocyte profiles/functionality, tumor necrosis factor-α content, as well as apoptosis and expression of nuclear factor-κB (NF-κB) among the tumor cells. The data indicate that MON induced significant antitumor activity against the SEC. MON treatments also significantly mitigated both tumor- and DOX-induced declines in immune parameters assessed here. Moreover, MON led to decreased NF-κB nuclear expression and, in doing so, appeared to chemosensitize these tumor cells to DOX-induced apoptosis.

Protective effects of alpha lipoic acid versus N-acetylcysteine on ifosfamide-induced nephrotoxicity.

Ifosfamide (IFO) is a highly effective chemotherapeutic agent for treating a variety of pediatric solid tumors. However, its use is limited due to its serious side effect on kidneys. The side-chain oxidation of IFO in renal tubular cells produces a reactive toxic metabolite that is believed to be responsible for its nephrotoxic effect. Therefore, this study was carried out to investigate the possible underlying mechanisms that may be involved in IFO-induced nephrotoxicity, including free radical generation and the possible role of alpha lipoic acid (ALA) versus N-acetylcysteine (NAC) in protection against this toxicity. Male albino rats were injected intraperitoneally with saline, IFO (50 mg/kg daily for 5 days), IFO + ALA (100 mg/kg daily for 8 days) and IFO + NAC (200 mg/kg daily for 8 days). Kidney malondialdehyde, nitric oxide and glutathione contents and serum biochemical parameters and histopathological analysis were determined. Both ALA and NAC markedly reduced the severity of renal dysfunction induced by IFO. NAC was more nephroprotective than ALA. This study suggests that oxidative stress is possibly involved in the IFO-induced nephrotoxicity in rats. The study also suggests the potential therapeutic role for ALA and NAC against IFO-induced nephrotoxicity.

Effect of atorvastatin and methotrexate on solid Ehrlich tumor.

Hydroxymethyl glutaryl CoA reductase is the key enzyme in cholesterol synthesis. A relationship was found between cholesterol and the development of many types of cancer. Atorvastatin is a hypolipidemic drug that may have a role in treatment of cancer. Moreover, atorvastatin was reported to decrease the resistance of cancer cells to many chemotherapeutic agents. The aim of this work was to study the effect of each of methotrexate (MTX) and atorvastatin alone and in combination on solid Ehrlich carcinoma (SEC) in mice. Fifty BALB/c mice were divided into five equal groups: control untreated group, SEC, SEC+MTX, SEC+atorvastatin, SEC+MTX+atorvastatin. Tumor volume, tissue glutathione reductase (GR), catalase, malondialdehyde (MDA), cholesterol and tumor necrosis factor alpha (TNF-α) were determined. A part of the tumor was examined for histopathological and immunohistochemical study. MTX or atorvastatin alone or in combination induced significant increase in tissue catalase and GR with significant decrease in tumor volume, tissue MDA, cholesterol and TNF-α and alleviated the histopathological changes with significant increase in p53 expression and apoptotic index compared to SEC group. In conclusion, the combination of MTX and atorvastatin had a better effect than each of MTX or atorvastatin alone against solid Ehrlich tumor in mice.