MyMedR

Displaying publications 1 - 20 of 55 in total

Abstract:

Sort:

Fulltext Interleukin-6 is required for pancreatic cancer progression by promoting MAPK signaling activation and oxidative stress resistance

Zhang Y, Yan W, Collins MA, Bednar F, Rakshit S, Zetter BR, et al.

Cancer Res, 2013 Oct 15;73(20):6359-74.
PMID: 24097820 DOI: 10.1158/0008-5472.CAN-13-1558-T

Pancreatic cancer, one of the deadliest human malignancies, is almost invariably associated with the presence of an oncogenic form of Kras. Mice expressing oncogenic Kras in the pancreas recapitulate the stepwise progression of the human disease. The inflammatory cytokine interleukin (IL)-6 is often expressed by multiple cell types within the tumor microenvironment. Here, we show that IL-6 is required for the maintenance and progression of pancreatic cancer precursor lesions. In fact, the lack of IL-6 completely ablates cancer progression even in presence of oncogenic Kras. Mechanistically, we show that IL-6 synergizes with oncogenic Kras to activate the reactive oxygen species detoxification program downstream of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling cascade. In addition, IL-6 regulates the inflammatory microenvironment of pancreatic cancer throughout its progression, providing several signals that are essential for carcinogenesis. Thus, IL-6 emerges as a key player at all stages of pancreatic carcinogenesis and a potential therapeutic target.

Matched MeSH terms: Oxidative Stress/physiology*
Comparative effects of alpha-tocopherol and gamma-tocotrienol against hydrogen peroxide induced apoptosis on primary-cultured astrocytes

Mazlan M, Sue Mian T, Mat Top G, Zurinah Wan Ngah W

J Neurol Sci, 2006 Apr 15;243(1-2):5-12.
PMID: 16442562

Oxidative stress is thought to be one of the factors that cause neurodegeneration and that this can be inhibited by antioxidants. Since astrocytes support the survival of central nervous system (CNS) neurons, we compared the effect of alpha-tocopherol and gamma-tocotrienol in minimizing the cytotoxic damage induced by H(2)O(2), a pro-oxidant. Primary astrocyte cultures were pretreated with either alpha-tocopherol or gamma-tocotrienol for 1 h before incubation with 100 microM H(2)O(2) for 24 h. Cell viability was then assessed using the MTS assay while apoptosis was determined using a commercial ELISA kit as well as by fluorescent staining of live and apoptotic cells. The uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes were also determined using HPLC. Results showed that gamma-tocotrienol is toxic at concentrations >200 microM but protects against H(2)O(2) induced cell loss and apoptosis in a dose dependent manner up to 100 microM. alpha-Tocopherol was not cytotoxic in the concentration range tested (up to 750 microM), reduced apoptosis to the same degree as that of gamma-tocotrienol but was less effective in maintaining the viable cell number. Since the uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes is similar, this may reflect the roles of these 2 vitamin E subfamilies in inhibiting apoptosis and stimulating proliferation in astrocytes.

Matched MeSH terms: Oxidative Stress/physiology
Fulltext Piper sarmentosum as an antioxidant on oxidative stress in human umbilical vein endothelial cells induced by hydrogen peroxide

Hafizah AH, Zaiton Z, Zulkhairi A, Mohd Ilham A, Nor Anita MM, Zaleha AM

J Zhejiang Univ Sci B, 2010 May;11(5):357-65.
PMID: 20443214 DOI: 10.1631/jzus.B0900397

Endothelial cell death due to increased reactive oxygen species (ROS) may contribute to the initial endothelial injury, which promotes atherosclerotic lesion formation. Piper sarmentosum (PS), a natural product, has been shown to have an antioxidant property, which is hypothesized to inhibit production of ROS and prevent cell injury. Thus, the present study was designed to determine the effects of PS on the hydrogen peroxide (H(2)O(2))-induced oxidative cell damage in cultured human umbilical vein endothelial cells (HUVECs). In this experiment, HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation (LSGS). HUVECs were treated with various concentrations of H(2)O(2) (0-1000 micromol/L) and it was observed that 180 micromol/L H(2)O(2) reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Using the above concentration as the positive control, the H(2)O(2)-induced HUVECs were concomitantly treated with various concentrations (100, 150, 250 and 300 microg/ml) of three different extracts (aqueous, methanol and hexane) of PS. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) levels showed a significant increase (P<0.05) in HUVECs compared to the negative control. However, PS extracts showed a protective effect on HUVECs from H(2)O(2)-induced cell apoptosis with a significant reduction in MDA, SOD, CAT and GPX levels (P<0.05). Furthermore, PS had exhibited ferric reducing antioxidant power with its high phenolic content. Hence, it was concluded that PS plays a beneficial role in reducing oxidative stress in H(2)O(2)-induced HUVECs.

Matched MeSH terms: Oxidative Stress/physiology*
Ischemic optic neuropathy as a model of neurodegenerative disorder: A review of pathogenic mechanism of axonal degeneration and the role of neuroprotection

Khalilpour S, Latifi S, Behnammanesh G, Majid AM, Majid AS, Tamayol A

J Neurol Sci, 2017 Apr 15;375:430-441.
PMID: 28320183 DOI: 10.1016/j.jns.2016.12.044

Optic neuropathy is a neurodegenerative disease which involves optic nerve injury. It is caused by acute or intermittent insults leading to visual dysfunction. There are number of factors, responsible for optic neuropathy, and the optic nerve axon is affected in all type which causes the loss of retinal ganglion cells. In this review we will highlight various mechanisms involved in the cell loss cascades during axonal degeneration as well as ischemic optic neuropathy. These mechanisms include oxidative stress, excitotoxicity, angiogenesis, neuroinflammation and apoptosis following retinal ischemia. We will also discuss the effect of neuroprotective agents in attenuation of the negative effect of factors involve in the disease occurrence and progression.

Matched MeSH terms: Oxidative Stress/physiology
Upregulation of catalase and downregulation of glutathione peroxidase activity in the kidney precede the development of hypertension in pre-hypertensive SHR

Sundaram A, Siew Keah L, Sirajudeen KN, Singh HJ

Hypertens Res, 2013 Mar;36(3):213-8.
PMID: 23096233 DOI: 10.1038/hr.2012.163

Although oxidative stress has been implicated in the pathogenesis of hypertension in spontaneously hypertensive rats (SHRs), there is little information on the levels of primary antioxidant enzymes status (AOEs) in pre-hypertensive SHR. This study therefore determined the activities of primary AOEs and their mRNA levels, levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) and total antioxidant status (TAS) in whole kidneys of SHR and age-matched Wistar-Kyoto (WKY) rats aged between 2 and 16 weeks. Compared with age-matched WKY rats, catalase (CAT) activity was significantly higher from the age of 2 weeks (P<0.001) and glutathione peroxide (GPx) activity was lower from the age of 3 weeks (P<0.001) in SHR. CAT mRNA levels were significantly higher in SHR aged 2, 4, 6 and 12 weeks. GPx mRNA levels were significantly lower in SHR at 8 and 12 weeks. Superoxide dismutase activity or its mRNA levels were not different between the two strains. H2O2 levels were significantly lower in SHR from the age of 8 weeks (P<0.01). TAS was significantly higher in SHR from the age of 3 weeks (P<0.05). MDA levels were only significantly higher at 16 weeks of age in the SHR (P<0.05). The data suggest that altered renal CAT and GPx mRNA expression and activity precede the development of hypertension in SHR. The raised CAT activity perhaps contributes to the higher TAS and lower H2O2 levels in SHR. In view of these findings, the precise role of oxidative stress in the pathogenesis of hypertension in SHR needs to be investigated further.

Matched MeSH terms: Oxidative Stress/physiology
6th COSTAM/SFRR (ASEAN/Malaysia) International Workshop on Micronutrients, Oxidative Stress, and the Environment

Nesaretnam K, Sies H

Antioxid Redox Signal, 2006 10 13;8(11-12):2175-7.
PMID: 17034360

The 6(th) COSTAM/SFRR (ASEAN/Malaysia) workshop, "Micronutrients, Oxidative Stress, and the Environment," was held from June 29 to July 2 at Holiday Inn Damai Beach Resort in Kuching, Sarawak. Two hundred twenty participants from 17 countries presented recent advances on natural antioxidants in the area of oxidative stress and molecular aspects of nutrition. Natural products and research are an important program in academic institutions and are experiencing unprecedented interest and growth by the scientific community and public health authorities. Progress is being driven by better understanding of the molecular mechanisms of the relation between oxidative stress and micronutrient action. The gathering of scientists from around the world was fruitful, and we hope that future work will be developed by the formal and informal interactions that took place in this beautiful tropical setting.

Matched MeSH terms: Oxidative Stress/physiology*
Effects of prolonged isolation in a confined space on status of oxidative stress and prothrombogenesis: In preparation for possible future manned space expedition to Mars

Muid S, Abu Bakar NA, Abdul Rahman T, Tengku Ismail TS, Kholin SF, Suvorov AV, et al.

Malays J Pathol, 2019 Dec;41(3):283-292.
PMID: 31901913

INTRODUCTION: Apart from inflammation and endothelial dysfunction, other key components in the development of atherogenesis include prothrombogenesis and oxidative stress. The effects of long-term confinement and isolation, exposure to radiation and different gravity forces during space travel could potentially increase the long-term risk of atherosclerosis. To the best of our knowledge, this is the first study determining the status of prothrombogenesis and oxidative stress in six cosmonauts subjected to the longest duration of confined isolation period of 520 days in preparation for prospective undetermined manned space travel to Mars.
MATERIALS AND METHODS: This collaborative research between the National Space Agency (ANGKASA), Universiti Teknologi MARA, Malaysia and Institute of Biomedical Problems (IBMP), Russia was conducted at the Russian Academy of Sciences IBMP, Moscow, Russia. Six multi-national cosmonauts were assigned to live in a ground-based confined module for 520 days. Standard exercise and diet regime were instituted throughout the isolation phase. Six age, ethnic and gender-matched healthy, free-living ground controls were recruited in parallel. Serial serum and whole blood were analysed for biomarkers of prothrombogenesis [plasminogen activator inhibitor-1 (PAI-1) and homocysteine] and oxidative stress [oxidised low-density lipoprotein (ox-LDL) and malondialdehyde (MDA)].
RESULTS: There were significantly lower concentrations of PAI-1 and homocysteine in cosmonauts during confinement compared to the controls. There were no significant differences seen in the concentrations of biomarkers of oxidative stress during confinement but there was a significant percentage change increment for serum MDA in cosmonauts.
CONCLUSION: Long-term confinement decreased the risk of prothrombogenesis and this could be attributed to the exercise and diet regime which includes omega-3 fatty acids supplementation given to the crew members during their confinement period. However, oxidative damage could not be excluded and may be attributed to the influence of psychological stress during this prolonged confinement.

Matched MeSH terms: Oxidative Stress/physiology*
Glycaemic control in relation to xanthine oxidase and antioxidant indices in Malaysian Type 2 diabetes patients

Kuppusamy UR, Indran M, Rokiah P

Diabet Med, 2005 Oct;22(10):1343-6.
PMID: 16176194 DOI: 10.1111/j.1464-5491.2005.01630.x

Aims: Increased oxidative stress and oxidative damage are present in Type 2 diabetes mellitus (DM). The aim of this study was to assess the oxidative stress levels in the three major ethnic groups in Malaysia and to study the association between glycaemic control and oxidant-antioxidant levels in these patients.

Methods: Oxidative indices and glycaemic control were assessed in 650 Type 2 DM patients and 280 healthy age-matched controls by known established methods.

Results: Type 2 DM patients had significantly lower levels of antioxidant enzymes and non-enzymatic antioxidant (FRAP) and increased levels of HbA(1c), fasting blood glucose (FBG), malondialdehyde (MDA) and xanthine oxidase (XO) when compared with control subjects. Markers of oxidative stress were more apparent in Indian patients compared with Malay and Chinese patients. Correlation analysis of oxidant-antioxidant parameters as a function of HbA(1c) in each ethnic group revealed a strong association of HbA(1c) with oxidative indices.

Conclusions: The present study provides evidence for the possible contribution of XO to oxidative stress and the pathophysiology of diabetes. HbA(1c) remains an important marker of glycaemic control for the management of Type 2 DM, but other confounding factors that predispose or lead to oxidative stress should also be taken into consideration.

Matched MeSH terms: Oxidative Stress/physiology
The oxidative stress of hyperglycemia and the inflammatory process in endothelial cells

Muniandy S, Qvist R, Yan GO, Bee CJ, Chu YK, Rayappan AV

J. Med. Invest., 2009 Feb;56(1-2):6-10.
PMID: 19262007

Hyperglycemia and insulin resistance are common in many critically ill patients. Hyperglycemia increases the production of reactive oxygen species in cells, stimulates the production of the potent proinflammatory cytokines IL-8 and TNF-alpha, and enhances the expression of haem oxygenase-1, an inducible stress protein. It has been shown that administration of insulin and the semi-essential amino acid glutamine have been beneficial to the septic patient. The aim of our study is to test whether these two molecules, glutamine and insulin used in combination attenuate the proinflammatory responses in endothelial cells which have been triggered by hyperglycaemia. Our results demonstrate that a combination of insulin and glutamine are significantly more effective in reducing the expression of IL-8, TNF-alpha and HO-1 than insulin or glutamine alone.

Matched MeSH terms: Oxidative Stress/physiology*
Erythrocyte indicators of oxidative changes in patients with graded traumatic head injury

Nayak CD, Nayak DM, Raja A, Rao A

Neurol India, 2008 3 4;56(1):31-5.
PMID: 18310834

CONTEXT: Acute oxidative stress following a traumatic head injury (HI) has been implicated in inducing severe secondary brain damage and influencing the clinical outcome of HI patients.
AIMS: This study was performed to evaluate and compare the oxidative changes in patients with varying severity of HI in the early posttraumatic period using erythrocyte indicators.
SETTINGS AND DESIGN: Head injury patients were divided into two groups based on their Glasgow Coma Scale (GCS) scores recorded at admission to the hospital on the day of trauma itself. Accordingly, the study included 30 severe HI (SHI, GCS scores 8 or less) and 25 Mild HI (MHI, GCS scores more than 8) patients. Thirty age and sex-matched healthy individuals were included in this comparative study as controls.
MATERIALS AND METHODS: Blood samples were obtained from controls and HI patients (within 24 h of trauma onset). Erythrocyte oxidative changes were studied by estimating thiobarbituric acid reactive substances (TBARS), glutathione (GSH), superoxide dismutase (SOD) and glutathione reductase (GR).
RESULTS: Erythrocyte TBARS levels were significantly higher and GSH levels were significantly lower in SHI and MHI patients as compared to controls. The SOD activity was significantly increased only in SHI patients and remained unchanged in MHI patients as compared to controls. As compared to MHI patients, erythrocyte TBARS levels were significantly higher, GSH levels were significantly lower and SOD activity was markedly elevated in SHI patients. Erythrocyte GR activity did not show significant changes in both groups of patients as compared to controls.
CONCLUSION: Oxidative stress is evident in both SHI and MHI patients in the early posttraumatic period as reflected by their erythrocyte indicators, but the severity of oxidative stress has varied relatively with the severity of head injury. The present findings provide indications that early oxidative changes could influence the neurological recovery of HI patients.

Matched MeSH terms: Oxidative Stress/physiology*
Fulltext Impaired redox environment modulates cardiogenic and ion-channel gene expression in cardiac-resident and non-resident mesenchymal stem cells

Subramani B, Subbannagounder S, Ramanathanpullai C, Palanivel S, Ramasamy R

Exp Biol Med (Maywood), 2017 03;242(6):645-656.
PMID: 28092181 DOI: 10.1177/1535370216688568

Redox homeostasis plays a crucial role in the regulation of self-renewal and differentiation of stem cells. However, the behavioral actions of mesenchymal stem cells in redox imbalance state remain elusive. In the present study, the effect of redox imbalance that was induced by either hydrogen peroxide (H2O2) or ascorbic acid on human cardiac-resident (hC-MSCs) and non-resident (umbilical cord) mesenchymal stem cells (hUC-MSCs) was evaluated. Both cells were sensitive and responsive when exposed to either H2O2 or ascorbic acid at a concentration of 400 µmol/L. Ascorbic acid pre-treated cells remarkably ameliorated the reactive oxygen species level when treated with H2O2. The endogenous antioxidative enzyme gene (Sod1, Sod2, TRXR1 and Gpx1) expressions were escalated in both MSCs in response to reactive oxygen species elevation. In contrast, ascorbic acid pre-treated hUC-MSCs attenuated considerable anti-oxidative gene (TRXR1 and Gpx1) expressions, but not the hC-MSCs. Similarly, the cardiogenic gene (Nkx 2.5, Gata4, Mlc2a and β-MHC) and ion-channel gene ( IKDR, IKCa, Ito and INa.TTX) expressions were significantly increased in both MSCs on the oxidative state. On the contrary, reduced environment could not alter the ion-channel gene expression and negatively regulated the cardiogenic gene expressions except for troponin-1 in both cells. In conclusion, redox imbalance potently alters the cardiac-resident and non-resident MSCs stemness, cardiogenic, and ion-channel gene expressions. In comparison with cardiac-resident MSC, non-resident umbilical cord-MSC has great potential to tolerate the redox imbalance and positively respond to cardiac regeneration. Impact statement Human mesenchymal stem cells (h-MSCs) are highly promising candidates for tissue repair in cardiovascular diseases. However, the retention of cells in the infarcted area has been a major challenge due to its poor viability and/or low survival rate after transplantation. The regenerative potential of mesenchymal stem cells (MSCs) repudiate and enter into premature senescence via oxidative stress. Thus, various strategies have been attempted to improve the MSC survival in 'toxic' conditions. Similarly, we investigated the response of cardiac resident MSC (hC-MSCs) and non-resident MSCs against the oxidative stress induced by H2O2. Supplementation of ascorbic acid (AA) into MSCs culture profoundly rescued the stem cells from oxidative stress induced by H2O2. Our data showed that the pre-treatment of AA is able to inhibit the cell death and thus preserving the viability and differentiation potential of MSCs.

Matched MeSH terms: Oxidative Stress/physiology
The influence of selenium status on body composition, oxidative DNA damage and total antioxidant capacity in newly diagnosed type 2 diabetes mellitus: A case-control study

Othman FB, Mohamed HJBJ, Sirajudeen KNS, Noh MFBM, Rajab NF

J Trace Elem Med Biol, 2017 Sep;43:106-112.
PMID: 28065595 DOI: 10.1016/j.jtemb.2016.12.009

Selenium is involved in the complex system of defense against oxidative stress in diabetes through its biological function of selenoproteins and the antioxidant enzyme. A case-control study was carried out to determine the association of plasma selenium with oxidative stress and body composition status presented in Type 2 Diabetes Mellitus (T2DM) patient and healthy control. This study involved 82 newly diagnosed T2DM patients and 82 healthy controls. Plasma selenium status was determined with Graphite Furnace Atomic Absorption Spectrometry. Body Mass Index, total body fat and visceral fat was assessed for body composition using Body Composition Analyzer (TANITA). Oxidative DNA damage and total antioxidant capacity were determined for oxidative stress biomarker status. In age, gender and BMI adjustment, no significant difference of plasma selenium level between T2DM and healthy controls was observed. There was as a significant difference of Oxidative DNA damage and total antioxidant capacity between T2DM patients and healthy controls with tail DNA% 20.62 [95% CI: 19.71,21.49] (T2DM), 17.67 [95% CI: 16.87,18.56] (control); log tail moment 0.41[95% CI: 0.30,0.52] (T2DM), 0.41[95% CI: 0.30,0.52] (control); total antioxidant capacity 0.56 [95% CI: 0.54,0.58] (T2DM), 0.60 [95% CI: 0.57,0.62] (control). Waist circumference, BMI, visceral fat, body fat and oxidative DNA damage in the T2DM group were significantly lower in the first plasma selenium tertile (38.65-80.90μg/L) compared to the second (80.91-98.20μg/L) and the third selenium tertiles (98.21-158.20μg/L). A similar trend, but not statistically significant, was observed in the control group.

Matched MeSH terms: Oxidative Stress/physiology
Fulltext Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin

Aziz J, Shezali H, Radzi Z, Yahya NA, Abu Kassim NH, Czernuszka J, et al.

Skin Pharmacol Physiol, 2016;29(4):190-203.
PMID: 27434176 DOI: 10.1159/000447017

Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.

Matched MeSH terms: Oxidative Stress/physiology*
Fulltext Oxidative stress and antioxidant status in primary bone and soft tissue sarcoma

Nathan FM, Singh VA, Dhanoa A, Palanisamy UD

BMC Cancer, 2011;11:382.
PMID: 21871117 DOI: 10.1186/1471-2407-11-382

Oxidative stress is characterised by an increased level of reactive oxygen species (ROS) that disrupts the intracellular reduction-oxidation (redox) balance and has been implicated in various diseases including cancer. Malignant tumors of connective tissue or sarcomas account for approximately 1% of all cancer diagnoses in adults and around 15% of paediatric malignancies per annum. There exists no information on the alterations of oxidant/antioxidant status of sarcoma patients in literature. This study was aimed to determine the levels of oxidative stress and antioxidant defence in patients with primary bone and soft tissue sarcoma and to investigate if there exists any significant differences in these levels between both the sarcomas.

Matched MeSH terms: Oxidative Stress/physiology*
Association of oxidative stress and memory performance in postmenopausal women receiving estrogen-progestin therapy

Shafin N, Zakaria R, Hussain NH, Othman Z

Menopause, 2013 Jun;20(6):661-6.
PMID: 23715378 DOI: 10.1097/GME.0b013e31827758c6

The aim of this study was to examine the association between changes in blood oxidative stress level/activity and changes in memory performance among postmenopausal women.

Matched MeSH terms: Oxidative Stress/physiology*
Fulltext Piper sarmentosum increases nitric oxide production in oxidative stress: a study on human umbilical vein endothelial cells

Ugusman A, Zakaria Z, Hui CK, Nordin NA

Clinics (Sao Paulo), 2010 Jul;65(7):709-14.
PMID: 20668629 DOI: 10.1590/S1807-59322010000700010

Nitric oxide produced by endothelial nitric oxide synthase (eNOS) possesses multiple anti-atherosclerotic properties. Hence, enhanced expression of eNOS and increased Nitric oxide levels may protect against the development of atherosclerosis. Piper sarmentosum is a tropical plant with antioxidant and anti-inflammatory activities. This study aimed to investigate the effects of Piper sarmentosum on the eNOS and Nitric oxide pathway in cultured human umbilical vein endothelial cells (HUVECs).

Matched MeSH terms: Oxidative Stress/physiology
Fulltext Modulation of P2Y6R expression exacerbates pressure overload-induced cardiac remodeling in mice

Shimoda K, Nishimura A, Sunggip C, Ito T, Nishiyama K, Kato Y, et al.

Sci Rep, 2020 08 18;10(1):13926.
PMID: 32811872 DOI: 10.1038/s41598-020-70956-5

Cardiac tissue remodeling caused by hemodynamic overload is a major clinical outcome of heart failure. Uridine-responsive purinergic P2Y6 receptor (P2Y6R) contributes to the progression of cardiovascular remodeling in rodents, but it is not known whether inhibition of P2Y6R prevents or promotes heart failure. We demonstrate that inhibition of P2Y6R promotes pressure overload-induced sudden death and heart failure in mice. In neonatal cardiomyocytes, knockdown of P2Y6R significantly attenuated hypertrophic growth and cell death caused by hypotonic stimulation, indicating the involvement of P2Y6R in mechanical stress-induced myocardial dysfunction. Unexpectedly, compared with wild-type mice, deletion of P2Y6R promoted pressure overload-induced sudden death, as well as cardiac remodeling and dysfunction. Mice with cardiomyocyte-specific overexpression of P2Y6R also exhibited cardiac dysfunction and severe fibrosis. In contrast, P2Y6R deletion had little impact on oxidative stress-mediated cardiac dysfunction induced by doxorubicin treatment. These findings provide overwhelming evidence that systemic inhibition of P2Y6R exacerbates pressure overload-induced heart failure in mice, although P2Y6R in cardiomyocytes contributes to the progression of cardiac fibrosis.

Matched MeSH terms: Oxidative Stress/physiology
Fulltext Comparison of serum F2 isoprostane levels in diabetic patients and diabetic patients infected with Burkholderia pseudomallei

Puthucheary SD, Nathan SA

Singapore Med J, 2008 Feb;49(2):117-20.
PMID: 18301838

Oxidative stress can occur in sepsis and infection, when overproduction of free radicals is not countered by the host antioxidant system, leading to impairment of host cellular functions. Various disease states are accompanied by the accumulation of 15-F2t-IsoP in biological fluids. These isoprostanes are considered as markers of oxidative stress, and inflammation and inflammatory mediators.

Matched MeSH terms: Oxidative Stress/physiology
Des-aspartate angiotensin I (DAA-I) reduces endothelial dysfunction in the aorta of the spontaneously hypertensive rat through inhibition of angiotensin II-induced oxidative stress

Loh WM, Ling WC, Murugan DD, Lau YS, Achike FI, Vanhoutte PM, et al.

Vascul. Pharmacol., 2015 Aug;71:151-8.
PMID: 25869508 DOI: 10.1016/j.vph.2015.03.011

Des-aspartate angiotensin I (DAA-I), an endogenous nonapeptide, counteracts several effects of angiotensin II on vascular tone. The aim of this study was to investigate the acute protective effect of DAA-I on endothelial function in the spontaneously hypertensive rat (SHR) as well as its effect on angiotensin II-induced contractions and oxidative stress. Aortic rings were incubated with DAA-I (0.1μM) for 30min prior to the assessment of angiotensin II-induced contractions (0.1nM-10μM) in WKY and SHR aortas. Total nitrate and nitrite levels were assessed using a colorimetric method and reactive oxygen species (ROS) were measured by dihydroethidium (DHE) fluorescence and lucigenin-enhanced chemiluminescence. The effect of DAA-I was also assessed against endothelium-dependent and -independent relaxations to acetylcholine and sodium nitroprusside, respectively. Angiotensin II-induced contractions were significantly reduced by DAA-I, losartan and tempol. Incubation with ODQ (soluble guanylyl cyclase inhibitor) and removal of the endothelium prevented the reduction of angiotensin II-induced contractions by DAA-I. Total nitrate and nitrite levels were increased in DAA-I, losartan and tempol treated-SHR tissues while ROS level was reduced by DAA-I and the latter inhibitors. In addition, DAA-I significantly improved the impaired acetylcholine-induced relaxation in SHR aortas whilst sodium nitroprusside-induced endothelium-independent relaxation remained unaffected. The present findings indicate that improvement of endothelial function by DAA-I in the SHR aorta is mediated through endothelium-dependent release of nitric oxide and inhibition of angiotensin II-induced oxidative stress.

Matched MeSH terms: Oxidative Stress/physiology
Boldine protects endothelial function in hyperglycemia-induced oxidative stress through an antioxidant mechanism

Lau YS, Tian XY, Huang Y, Murugan D, Achike FI, Mustafa MR

Biochem Pharmacol, 2013 Feb 1;85(3):367-75.
PMID: 23178655 DOI: 10.1016/j.bcp.2012.11.010

Increased oxidative stress is involved in the pathogenesis and progression of diabetes. Antioxidants are therapeutically beneficial for oxidative stress-associated diseases. Boldine ([s]-2,9-dihydroxy-1,10-dimethoxyaporphine) is a major alkaloid present in the leaves and bark of the boldo tree (Peumus boldus Molina), with known an antioxidant activity. This study examined the protective effects of boldine against high glucose-induced oxidative stress in rat aortic endothelial cells (RAEC) and its mechanisms of vasoprotection related to diabetic endothelial dysfunction. In RAEC exposed to high glucose (30 mM) for 48 h, pre-treatment with boldine reduced the elevated ROS and nitrotyrosine formation, and preserved nitric oxide (NO) production. Pre-incubation with β-NAPDH reduced the acetylcholine-induced endothelium-dependent relaxation; this attenuation was reversed by boldine. Compared with control, endothelium-dependent relaxation in the aortas of streptozotocin (STZ)-treated diabetic rats was significantly improved by both acute (1 μM, 30 min) and chronic (20mg/kg/daily, i.p., 7 days) treatment with boldine. Intracellular superoxide and peroxynitrite formation measured by DHE fluorescence or chemiluminescence assay were higher in sections of aortic rings from diabetic rats compared with control. Chronic boldine treatment normalized ROS over-production in the diabetic group and this correlated with reduction of NAD(P)H oxidase subunits, NOX2 and p47(phox). The present study shows that boldine reversed the increased ROS formation in high glucose-treated endothelial cells and restored endothelial function in STZ-induced diabetes by inhibiting oxidative stress and thus increasing NO bioavailability.

Matched MeSH terms: Oxidative Stress/physiology

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links