Melatonin effects on myocardial ischemia-reperfusion injury: Impact on the outcome in patients undergoing coronary artery bypass grafting surgery.

BACKGROUND: Myocardial ischemia/reperfusion injury represents a clinically critical problem associated with coronary artery bypass graft surgery (CABG). The degree of oxidative stress, inflammation and apoptosis are increased during the reperfusion of the heart muscles following ischemia. The present study aims to examine the protective role of melatonin in ameliorating the degree of cardiac injury in patients undergoing bypass surgery, and whether this effect is a dose related. METHODS: A total of forty-five patients who were undergoing elective CABG in (Al-Najaf Cardiac Center, Al-Najaf, Iraq) were included in this study for the period between January, 2015 and November, 2015. Participants were randomly allocated into 3 study groups: Placebo-controlled group (C), low dose melatonin treatment group, 10mg capsule once daily (M1) and high dose melatonin treatment group 20mg capsule once daily (M2). RESULTS: Compared to the control group, there was a significant increase in the ejection fraction (EF%) associated with a significant decline in heart rate (HR) among the M1 and M2 groups compared to the C group (P<0.05). In addition, there was a significant reduction in plasma levels of cardiac Troponin-I (CTnI), interleukin-1beta (IL-1ß), Inducible nitric oxide synthase (iNOS) and caspase-3 enzymes in the melatonin groups (group M1 and M2) compared to the control group, (P<0.05) in Melatonin-treated groups. Comparing the two melatonin study groups, the changes in the parameters mentioned above were more significant in the M2 group compared to the M1 group (P<0.05). CONCLUSION: These findings suggested that melatonin supplementation can ameliorate the degree of myocardial ischemic-reperfusion injury, dose dependent effects.

Blockade of the monocyte chemoattractant protein-1 receptor pathway ameliorates myocardial injury in animal models of ischemia and reperfusion.

BACKGROUND: Myocardial infarction is accompanied by inflammatory responses that lead to the recruitment of leukocytes and subsequent myocardial damage and healing. Monocyte chemoattractant protein-1 (MCP-1, also known as CC chemokine ligand 2) and its receptor CC chemokine receptor 2 play a central role in the inflammatory response and myocardial injury after ischemia/reperfusion (I/R). METHODS: Male adult C57BL/6 mice were anesthetized, and the left anterior descending coronary artery was ligated for 30 min. After reperfusion for 3 days, the ischemia and infarct sizes were determined. RESULTS: The treatment of C57BL/6 mice with anti-MCP-1 reduced the infarct size and lessened myocardial inflammation. Furthermore, anti-MCP-1 prevented I/R-induced caspase-3/7 and -8 activities and reduced apoptosis. The treatment of operated mice with anti-MCP-1 shortly before the induction of myocardial ischemia resulted in a reversal of the infarction and improvements in histologic parameters. CONCLUSION: These findings demonstrate a pathogenic role for MCP-1 in animal models of I/R and support the consideration of MCP-1 as a therapeutic target in myocardial ischemia.

Apoptosis amelioration through hypothermic reperfusion in heart transplant.

OBJECTIVE: To investigate the effects of two different sets of graft temperature during perfusion on myocardial protection in the immediate post transplantation period in rats. MATERIALS AND METHODS: RATS GROUPED INTO: Sham and two study groups, which include two set groups of heterotopic heart transplant perfused at two different temperature set. The studied groups underwent cuff method cervical heterotopic heart transplant. Myocardial cell injury and stress were assessed by measuring: Cardiac troponin-I, score of tissue injury, reactive oxygen species (ROS) and nitrogen, caspase 3 enzyme, and degree of myocardial apoptosis. The low set temperature (18°C) significantly reduced myocardial cell injury compared to 37°C reperfusion temperature. This cytoprotective effect of low temperature reperfusion phase was addressed by significant reduction in ROS and nitrogen and inflammatory cytokines, caspase 3, and myocardial apoptosis. CONCLUSION: Hypothermic reperfusion phase exerts cytoprotection in heart transplant through down regulation of oxygen, nitrogen reactive species, and inhibition of apoptosis.

Effects of thyroid hormone analogue and a leukotrienes pathway-blocker on reperfusion injury attenuation after heart transplantation.

Background. Global myocardial ischemia reperfusion injury after heart transplantation is believed to impair graft function and aggravate both acute and chronic rejection episodes. Objectives. To assess the possible protective potential of MK-886 and 3,5-diiodothyropropionic acid DITPA against global myocardial ischemia reperfusion injury after heart transplantation. Materials and Methods. Adult albino rats were randomized into 6 groups as follows: group I sham group; group II, control group; groups III and IV, control vehicles (1,2); group V, MK-886 treated group. Donor rats received MK-886 30 min before transplantation, and the same dose was repeated for recipients upon reperfusion; in group VI, DITPA treated group, donors and recipients rats were pretreated with DITPA for 7 days before transplantation. Results. Both MK-886 and DITPA significantly counteract the increase in the levels of cardiac TNF- α , IL-1 ß , and ICAM-1 and plasma level of cTnI (P < 0.05). Morphologic analysis showed that both MK-886 and DITPA markedly improved (P < 0.05) the severity of cardiac injury in the heterotopically transplanted rats. Conclusions. The results of our study reveal that both MK-886 and DITPA may ameliorate global myocardial ischemia reperfusion injury after heart transplantation via interfering with inflammatory pathway.

Role of NF-κß and oxidative pathways in atherosclerosis: cross-talk between dyslipidemia and candesartan.

PURPOSE: The objective of this study is to assess the effect of the candesartan on the progression of atherosclerosis through the downregulation of NF-κß and interference with oxidative pathway. METHODS: Twenty-four rabbits were assigned to three groups: control group fed normal diet; induced untreated group fed 1% cholesterol diet; and treated candesartan group also fed 1% cholesterol diet. Plasma lipid profiles were measured, and ELISA for plasma cytokines and chemokine was performed. Analyses of NF-κß and VCAM-1 were performed using Western blotting with RT-PCR for NF-κB activity at mRNA. Doppler ultrasound was used to evaluate aortic intima-media thickness, and atheroma was detected by H&E staining. Immunofluorescent staining was performed to confirm accumulation of monocytes and PMNs. RESULTS: Candesartan markedly reduced the levels of the plasma lipid profile including total cholesterol [TC], triglycerides [TG], and LDL-C, while significantly elevating levels in the plasma HDL-C, in addition to reducing cytokine (TNF-α, IL-6, IL-1ß) and chemokine levels (MCP-1). Also, it decreased the aortic malondialdehyde (MDA) concentration and elevated the aortic glutathione (GSH) level compared with untreated animals (P < 0.05). The triplex Doppler ultrasound study confirmed that the candesartan attenuated intima-media thickness at 6 months of study. All candesartan-treated rabbits showed significantly attenuated atherosclerosis lesions with reduced accumulation of monocytes and had significantly reduced VCAM-1 expression and NF-κß activity. CONCLUSION: Candesartan retards the progression of atherosclerosis via interference with NF-κß and oxidative pathways.

Expression of IL-32 modulates NF-κB and p38 MAP kinase pathways in human esophageal cancer.

BACKGROUND: Esophageal cancer is the seventh leading cause of cancer death in males in USA, and there is a strong link has been demonstrated between inflammation and esophageal cancer, interleukin (IL)-32 is a recently described pro-inflammatory cytokine characterized by the induction of nuclear factor NF-κB activation, the p38MAPK also plays an important role in key cellular processes related to inflammation and cancer. We investigated whether the IL-32 expression may be involved in esophageal carcinogenesis through modulates the activity of NF-κB and p-p38 MAPK. METHOD: Malignant esophageal tissue and blood samples were obtained from 65 operated untreated patients, normal samples was obtained from 35 patients operated for other reasons as control. IL-32 expression visualized by immunohistochemistry, Real time RT-PCR for IL-32 mRNA expression, NF-κB phosphorylation and phosphorylated p38mapk were analyzed by immunoblotting, ELISA for further detection IL-32 and cytokines (TNF-α, IL-1ß, IL-6 and IL-8) concentration in the patient's sera. RESULTS: IL-32 expression was increased in immunohistochemical staining for malignant esophageal tissue and it's correlated with the relative expression level of IL-32 mRNA P=0.007, the P-NF-κB level elevated in tumor tissue compared with control and no difference in the total NF-κB level P=0.003 while the IL-32 up-regulated the P-pNF-κB in the esophageal tumor P=0.005. There is increase in p-p38MAPK activation underlying IL-32 expression in tumor P=0.004, but no change in total p38 MAPK in malignant esophagus. The plasma level of IL-32 expression was increased in malignant esophageal patients P=0.01, with increased in the levels of the cytokines TNF-α, IL-6, and IL-1ßP<0.05. CONCLUSIONS: Understanding the pathway of IL-32 expression to stimulate the secretion cytokines via the activation of NF-κB and up-regulation of p-p38MAPK may or may not prove to be a therapeutic target, or a biomarker, and future studies will finally answer this hypothesis generated.

Cysteinyl leukotriene receptor antagonist montelukast ameliorates acute lung injury following haemorrhagic shock in rats.

OBJECTIVES: The aim of this study was to assess the possible protective effect of montelukast against haemorrhagic shock-induced acute lung injury by interfering with inflammatory and oxidative pathways. Acute lung injury following haemorrhagic shock/resuscitation is an important contributor to late morbidity and mortality in trauma patients. Haemorrhagic shock (HS), followed by resuscitation, is considered to be an insult that frequently induces systemic inflammatory response syndrome and oxidative stress, resulting in multiple-organ dysfunction syndrome, including microvascular changes and microscopic damage termed acute lung paraynchymal injury. Montelukast is a cysteinyl leukotriene receptor antagonist that exerts an anti-inflammatory and antioxidant influence. METHODS: Eighteen adult albino rats were assigned to three groups of six. In Group I, the 'sham' group, rats underwent all the surgical procedures but neither haemorrhagic shock nor resuscitation was carried out. Group II--the 'HS' induced, untreated group--was the control and underwent HS for one hour before being resuscitated with Ringer's lactate for one hour. Group III--the 'montelukast' group--underwent HS and treatment with montelukast (7 mg/kg i.p. injection) 30 min before the induction of HS, with the same dose repeated just before the reperfusion period. At the end of the experiment, two hours after completion of resuscitation, blood samples were collected for measurement of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The trachea was then isolated and bronchoalveolar lavage was carried out for measurement of leukotriene B(4) (LTB(4)), leukotriene C(4) (LTC(4)) and total protein. The lungs were harvested and the left lung was homogenized for measurement of malondialdehyde (MDA) and reduced glutathione (GSH) and the right lung was fixed in 10% formalin for histological examination. RESULTS: Montelukast treatment (Group III) significantly reduced the total lung injury score, compared with the HS group (Group II) (P < 0.05). Montelukast also significantly decreased serum TNF-α and IL-6; lung MDA; bronchoalveolar lavage fluid (BALF) LTB(4), LTC(4) & total protein compared with the HS group (P < 0.05). Montelukast treatment significantly inhibited decrease in the lung GSH levels, compared with the HS group (P < 0.05). CONCLUSIONS: The results of the present study reveal that montelukast may ameliorate lung injury in shocked rats by interfering with inflammatory and oxidative pathways, implicating the role of leukotrienes in the pathogenesis of haemorrhagic shock-induced lung inflammation.

Metformin ameliorates methotrexate-induced hepatotoxicity.

OBJECTIVE: To study the effect of metformin on amelioration of hepatotoxicity induced by methotrexate. MATERIALS AND METHODS: After a 2-weeks of acclimatization period, the animals were randomly separated into three groups (seven rabbits each), all groups were maintained on standard chow diet throughout the experiment (8 weeks). Group 1 was treated with normal saline water (control), Group 2 with methotrexate (MTX, hepatotoxic), and Group 3 with MTX plus metformin. Induction of hepatotoxicity was carried out by administration of MTX to the rabbit in a dose of 0.25 mg/kg /day i.m. for 8 weeks. RESULTS: The treatment with MTX to rabbits for 8 weeks resulted in significant changes in serum liver enzymes, as compared to the baseline group. SGOT, SGPT, ALP, and bilirubin were significantly increased (P < 0.001), while total serum protein was significantly decreased. Similarly, 8 weeks of MTX treatment produced significant (P < 0.001) prolongation in PT. PTT was not significantly changed. It was found that serum MDA levels and SOD activity were significantly increased (P < 0.001), while serum GSH levels were significantly decreased (P < 0.001). Adding metformin to MTX is found to be significantly (P < 0.001) reduced the liver function test and shortening of PT and a significant increase in TSP (P < 0.001). CONCLUSION: It can be concluded that administration of metformin restored the altered liver function parameters and produced significant improvement in liver histopathological findings. Therefore, this additive drug possesses hepatoprotection against MTX-induced hepatotoxicity.

Vitamin E and telmisartan attenuates doxorubicin induced cardiac injury in rat through down regulation of inflammatory response.

BACKGROUND: The importance of doxorubicin (Dox), as a potent antitumor antibiotic, is limited by the development of life-threatening cardiomyopathy. It has been shown that free radicals are involved in acute doxorubicin-induced toxicity. The aim of this study was to determine the protective effect of vitamin E and telmisartan in acute doxorubicin induced cardiotoxicity. METHODS: Thirty two male Sprague - Dawley rats were involved in this study and were randomly separated into 4 groups, eight rats in each group, one group received normal saline I.P as control and second group received doxorubicin 20 mg/kg I.P, the other two groups also received doxorubicin 20 mg/kg I.P as single dose after seven cumulative doses (for seven days) of vitamin E (100 mg/kg) and telmisartan (1 mg/kg) respectively. Immunofluorescent staining for monocytes infiltration and analyses of plasma by (ELISAs) for MCP-1and troponin I. Western immunoblotting assay for ICAM-1, while left ventricular function was analyzed by microcatheter, also estimated the level of oxidative stress parameters (MDA and Catalase) and cardiac enzymes activities (CK-MB and LDH) before starting drugs treatment and after treatment period by 48 hours. RESULTS: The immunofluorescent staining showed that administration of vitamin E and telmisartan are attenuated of mononuclear cell infiltration; (p < 0.05 vs. Dox group), also reduced the level of chemokines MCP-1 and ICAM-1 expression compared with Dox group only, and there is marked reduction of myocardial troponin-I levels with improved LV function in vitamin E and telmisartan treated group. Doxorubicin treatment increased MDA, LDH, CK-MB levels significantly (P < 0.01), and were counteracted by administration of vitamin E and telmisartan, but did not significantly affect serum catalase activity. CONCLUSIONS: Antioxidant effect (vitamin E and telmisartan) have been shown to decrease doxorubicininduced cardiotoxicity.

Autonomic cerebral vascular response to sildenafil in diabetic patient.

BACKGROUND: Erectile dysfunction is a common problem in type 2 diabetic patients who are at higher risk of cerebrovascular events, and it's recorded with sildenafil, a drug which is primarily used for erectile dysfunction. OBJECTIVES: We tested the hypothesis whether or not sildenafil modulates cerebrovascular reactivity (CVR) in patients with type 2 diabetes mellitus. METHODS: A total of 35 male participants were enrolled; eighteen with type 2 diabetes mellitus matched with seventeen normal individuals. Transcranial Doppler Ultrasonographic examination (TCD) was performed for all participants to insonate the middle cerebral artery (MCA) through a trans-temporal window. CVR was assessed by using breath holding (BH)-hyperventilation (HV) test, before and after oral 50 mg sildenafil; recordings were analyzed by using SPSS program version 12. RESULTS: In normal individuals, sildenafil did not result in statistically significant change in breath holding index (BHI) from 0.91 ± 0.11 to 0.81 ± 0.09 and full range of vasodilatation (FVD) from (59.4% ± 6.3%) to (53.7% ± 4.9%). In diabetic patients, giving sildenafil resulted in significant increase in BHI (from 0.74 ± 0.14 to 1.03 ± 0.14) and FVD (from 60.2% ± 4.96% to 74% ± 4.8%), (p < 0.05). CONCLUSION: Sildenafil significantly improves CVR in type 2 diabetic patients but not in normal subjects.

Effects of thyroid hormone analogue and a leukotrienes pathway-blocker on renal ischemia/reperfusion injury in mice.

BACKGROUND: Acute renal failure (ARF) is an important clinical problem with a high mortality and morbidity. One of the primary causes of ARF is ischemia/reperfusion (I/R). Inflammatory process and oxidative stress are thought to be the major mechanisms causing I/R. MK-886 is a potent inhibitor of leukotrienes biosynthesis which may have anti-inflammatory and antioxidant effects through inhibition of polymorphonuclear leukocytes (PMNs) infiltration into renal tissues. 3, 5-diiodothyropropionic acid (DITPA) have evidences of improving effects on I/R in heart through modulation of cellular signaling in response to ischemic stress. The objective of present study was to assess the effects of MK-886 and DITPA on renal I/R injury. METHODS: A total of 24 Adult males of Swiss albino mice were randomized to four groups: I/R group (n = 6), mice underwent 30 minute bilateral renal ischemia and 48 hr reperfusion. Sham group (n = 6), mice underwent same anesthetic and surgical procedures except for ischemia induction. MK-886-treated group: (n = 6), I/R + MK-886 (6 mg/kg) by intraperitoneal injection. DITPA-treated group: (n = 6), I/R + DITPA (3.75 mg/kg) by intraperitoneal injection.After the end of reperfusion phase mice were sacrificed, blood samples were collected directly from the heart for determination of serum TNF-a, IL-6, urea and Creatinine. Both kidney were excised, the right one homogenized for oxidative stress parameters (MDA and GSH) measurements and the left kidney fixed in formalin for histological examination. RESULTS: Serum TNF-α, IL-6, urea and Creatinine, kidney MDA levels and scores of histopathological changes were significantly (P < 0.05) elevated in I/R group as compared with that of sham group. Kidney GSH level was significantly (P < 0.05) decreased in I/R group as compared with that of sham group. MK-886 treated group has significantly (P < 0.05) lowered levels of all study parameters except for GSH level which was significantly (P < 0.05) higher as compared with that of I/R group. DITPA caused non-significant (P > 0.05) changes in levels of all study parameters as compared with that of I/R group. CONCLUSION: The results of the present study show that MK-886 significantly ameliorated kidney damage that resulted from I/R. For DITPA, as its administration might not be successful, administration using a different protocol may give different effects on I/R.

Novel Toll-like receptor-4 deficiency attenuates trastuzumab (Herceptin) induced cardiac injury in mice.

BACKGROUND: Cardiac inflammation and generation of oxidative stress are known to contribute to trastuzumab (herceptin) induced cardiac toxicity. Toll-like receptors (TLRs) are a part of the innate immune system and are involved in cardiac stress reactions. Since TLR4 might play a relevant role in cardiac inflammatory signaling, we investigated whether or not TLR4 is involved in trastuzumab induced cardiotoxicity. METHODS: Seven days after a single injection of herceptin (2 mg/kg; i.p.), left ventricular pressure volume loops were measured in HeN compotent (TLR4+/+) and HeJ mutant (TLR4-/-) treated with trastuzumab and control mice. Immunofluorescent staining for monocyte infiltration and analyses of plasma by (ELISAs) for different chemokines including: MCP-1and tumor necrosis factor-α (TNF-α), Western immunoblotting assay for ICAM-1, and used troponin I for cardiac injury marker. RESULTS: Trastuzumab injection resulted in an impairment of left ventricular function in TLR-4 competent (HeN), in contrast TLR4-/- trastuzumab mice showed improved left ventricular function EF%, CO; p < 0.05, attenuation of mononuclear cell infiltration in TLR4 -/-; p < 0.05 vs.TLR-4 competent (HeN), reduced level of cytokines TNF-α, MCP-1 and ICAM-1 expression in TLR4-/-, marked reduction of myocardial troponin-I levels in TLR4-deficient mice. Data are presented as means ± SE; n = 8 in each group p < 0.05 vs.TLR-4 competent (HeN). CONCLUSIONS: Treatment with trastuzumab induces an inflammatory response that contributes to myocardial tissue TLR4 mediates chemokine expression (TNF-α, MCP-1and ICAM-1), so in experimental animals TLR4 deficiency improves left ventricular function and attenuates pathophysiological key mechanisms in trastuzumab induced cardiomyopathy.

Leukotriene biosynthesis inhibition ameliorates acute lung injury following hemorrhagic shock in rats.

BACKGROUND: Hemorrhagic shock followed by resuscitation is conceived as an insult frequently induces a systemic inflammatory response syndrome and oxidative stress that results in multiple-organ dysfunction syndrome including acute lung injury. MK-886 is a leukotriene biosynthesis inhibitor exerts an anti inflammatory and antioxidant activity. OBJECTIVES: The objective of present study was to assess the possible protective effect of MK-886 against hemorrhagic shock-induced acute lung injury via interfering with inflammatory and oxidative pathways. MATERIALS AND METHODS: Eighteen adult Albino rats were assigned to three groups each containing six rats: group I, sham group, rats underwent all surgical instrumentation but neither hemorrhagic shock nor resuscitation was done; group II, Rats underwent hemorrhagic shock (HS) for 1 hr then resuscitated with Ringer's lactate (1 hr) (induced untreated group, HS); group III, HS + MK-886 (0.6 mg/kg i.p. injection 30 min before the induction of HS, and the same dose was repeated just before reperfusion period). At the end of experiment (2 hr after completion of resuscitation), blood samples were collected for measurement of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The trachea was then isolated and bronchoalveolar lavage fluid (BALF) was carried out for measurement of leukotriene B4 (LTB4), leukotriene C4 (LTC4) and total protein. The lungs were harvested, excised and the left lung was homogenized for measurement of malondialdehyde (MDA) and reduced glutathione (GSH) and the right lung was fixed in 10% formalin for histological examination. RESULTS: MK-886 treatment significantly reduced the total lung injury score compared with the HS group (P < 0.05). MK-886 also significantly decreased serum TNF-α & IL-6; lung MDA; BALF LTB4, LTC4 & total protein compared with the HS group (P < 0.05). MK-886 treatment significantly prevented the decrease in the lung GSH levels compared with the HS group (P < 0.05). CONCLUSIONS: The results of the present study reveal that MK-886 may ameliorate lung injury in shocked rats via interfering with inflammatory and oxidative pathways implicating the role of leukotrienes in the pathogenesis of hemorrhagic shock-induced lung inflammation.