Stress In Various Diseases Research Articles

Polyphenols protect against age-associated apoptosis in female rat cochleae.

Dietary antioxidants, polyphenols, have been found to be beneficial in protecting against the generation of oxidative stress in various diseases associated with aging. Age-related hearing loss (AHL) is the number one neurodegenerative disorder on our aged population. Sprague-Dawley rats divided into five groups according to their age (3, 6, 12, 18 and 24months old) and treated with 100mg/day/kg body weight of polyphenols were used. Then, cochleae were harvested to measure caspase activities (-3, -8 and -9), caspase-3 gene expression, ATP levels, Bax, BcL-2 and p53 levels. 8-OHdG levels (marker of DNA oxidative damage) and annexin-V were also measured in cochleae. Increased levels of caspase-3 and 9 in cochlea were observed with age and this effect was attenuated by polyphenol treatment. In addition, ATP and Bcl-2 levels in older rats were recovered after administration of polyphenols, while Bax and p53 levels protein decreased. Oral supplementation with polyphenols also reduces DNA oxidative damage of cochlear cell. Treatment with polyphenols inhibits the activation of age-related apoptotic signaling by decreasing oxidative stress inside the rat cochlea.

GC-MS Analysis of Lipid Oxidation Products in Blood, Urine, and Tissue Samples.

Oxidant stress has been identified as important in the pathology of many diseases. Oxidation products of polyunsaturated fatty acids collectively termed isoprostanes, neuroprostanes, and isofurans are considered the most reliable measures of in vivo lipid oxidation, and they are widely used to assess oxidant stress in various diseases. Here we describe the measurement of these lipid oxidation products using gas chromatography mass spectrometry with electron capture negative ionization.

Oxidative stress--a key emerging impact factor in health, ageing, lifestyle and aesthetics.

Oxidative stress is the resultant damage that arises due to redox imbalances, more specifically an increase in destructive free radicals and reduction in protection from antioxidants and the antioxidant defence pathways. Oxidation of lipids by reactive oxygen species (ROS) can damage cellular structures and result in premature cell death. At low levels, ROS-induced oxidative stress can be prevented through the action of antioxidants, however, when ROS are present in excess, inflammation and cytotoxicity eventually results leading to cellular oxidative stress damage. Increasing evidence for the role of oxidative stress in various diseases including neurological, dermatological, and cardiovascular diseases is now emerging. Mitochondria are the principal source (90%) of ROS in the cell, with superoxide radicals being generated when molecular oxygen is combined with free electrons. Given the key role of mitochondria in the generation of cellular oxidative stress it is worth considering this organelle and the process in more detail and to provide methods of intervention.

Role of oxidative stress in various diseases: Relevance of dietary antioxidants

Oxidative stress plays important role in the pathophysiology of various diseases. Oxidative stress is caused in body due to an imbalance between the activities of endogenous pro-oxidative enzymes. Cellular antioxidants are known to change their redox state and they can be targeted for destruction, regulate oxidative processes involved signal transduction, effect gene expression and the pathways of cell proliferation and death. Oxidants and antioxidants play an important role in maintaining a balance between free radicals produced by metabolism or derived from environmental sources and the antioxidant system of the body. A natural antioxidant system exists in the biological systems which is responsible for prevention of damage by pro-oxidants. Impaired endogenous antioxidant system results in accumulation of free radicals, which not only induces lipid peroxidation but also imposes severe stress on the body leading to many diseases such as Alzheimer’s disease, Parkinson disease, Diabetic neuropathy, various cardiovascular diseases. Antioxidant system may be intrinsic or extrinsic. Intrinsic involves body own neutralizing systems and extrinsic antioxidant involves dietary supplements that are taken in the form of food like vitamin C, vitamin E and beta carotene that can be gained from the fruits and vegetables for the prevention and management of diseases induced by free radicals.

Hydrogen improves neurological function through attenuation of blood-brain barrier disruption in spontaneously hypertensive stroke-prone rats.

BackgroundEnhanced oxidative stress occurs in spontaneously hypertensive stroke-prone rats (SHRSP), and is important in blood–brain barrier (BBB) disruption. Hydrogen can exert potent protective cellular effects via reduction in oxidative stress in various diseases. The present study investigated whether long-term hydrogen treatment can improve neurological function outcome in the SHRSP model, and the effects of hydrogen on BBB function, especially the oxidative stress and the activity of matrix metalloproteinases (MMPs) in this model. Fifty-six animals were randomly assigned to 2 groups and treated as follows: SHRSP treated with hydrogen-rich water (HRW) (HRW group, n = 28); and SHRSP treated with regular water (control group, n = 28). The effect of HRW on overall survival and neurological function, and the effects of HRW on reactive oxygen species, BBB function, and MMP activities were examined.ResultsHRW treatment improved neurological function and tended to improve overall survival but without significant difference. The numbers of bleeds and infarcts were lower in the cortex and hippocampus in the HRW group. The HRW group exhibited a significantly lower number of 8-hydroxy-2'-deoxyguanosine-positive cells and vessels of extravasated albumin in the hippocampus compared with the control group. MMP-9 activity was reduced in the hippocampus in the HRW group compared with the control group.ConclusionsThe present study suggests that ingestion of HRW can improve neurological function outcome in the SHRSP model. This beneficial effect may be due to attenuation of BBB disruption via reduction in reactive oxygen species and suppression of MMP-9 activity in the hippocampus.

Antioxidant and methyl donor effects of betaine versus ethanol-induced oxidative stress in the rat liver

Oxidative stress is one hypothesis for the association of ethanol consumption with cardiovascular, cerebrovascular, and liver diseases. Thus, we examined whether oral betaine can act as a preventive agent in ethanol-induced oxidative stress on the rat liver. A total of 32 male Sprague–Dawley rats were divided into four equal groups. The control group received normal saline. The ethanol group was administered ethanol (4 g/kg). The betaine group received betaine [1.5 % (w/w) of the total diet], and the betaine plus ethanol group (Bet. & Eth.) were administered with betaine; after 120 min, the rats received ethanol. All of the treatments were applied for 2 months via gavage. Elevation of glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were observed in the betaine-treated groups. Thiobarbituric acid reactive substances (TBARS, an indicator of lipid peroxidation) concentration also decreased in the betaine-treated rats as compared to the ethanol group. There was also a significant reduction in plasma total homocysteine (tHcy) concentration in the betaine and Bet. & Eth. groups as compared to the ethanol-treated rats. In contrast, ethanol treatment in rats resulted in significant lower antioxidant enzyme activities (GPx and SOD), and indicated lipid peroxidation to the liver, as monitored by the elevation in TBARS level. Administration of ethanol to rats also induced toxicity in their liver, as shown by the histopathological findings, whereas betaine could suppress liver damages in the Bet. & Eth. group. Overall, oral pretreatment with betaine significantly prevented ethanol-induced oxidative stress and hyperhomocysteinemia via increasing antioxidant enzyme activities and decreasing tHcy concentration. Thus, betaine may be recommended as a therapeutic agent for patients with liver damages induced by oxidative stress in various diseases.

Urinary 8-hydroxydeoxyguanosine correlate with hallucinations rather than motor symptoms in Parkinson’s disease

BackgroundOxidative stress is causally associated with the pathogenesis of Parkinson’s disease (PD). Oxygen generates a large amount of reactive oxygen species (ROS). ROS including hydroxyl radicals and H2O2 react with guanine residues in DNA and produce 8-hydroxydeoxyguanosine (8-OHdG). 8-OHdG serves as a biomarker for oxidative stress in various diseases. MethodWe investigated urinary 8-OHdG levels in 61 PD patients and 28 normal subjects to evaluate the correlation with various clinical features. We quantified disease severity using the Unified Parkinson’s Disease Rating Scale for motor symptoms (UPDRS part 3), the Mini-Mental State Examination (MMSE) for mental function, and the Tottori University Hallucination Rating Scale (TUHARS) for quantifying hallucinations. ResultsThere were significant correlations between 8-OHdG and all the examined parameters, but the partial correlation coefficients excluding contributions of all the other parameters showed that only TUHARS and UPDRS part 3 are significantly related to 8-OHdG. In particular, TUHARS correlates best with urinary 8-OHdG levels. ConclusionThe significant correlation between urinary 8-OHdG levels and hallucinations but not with dementia suggests that hallucinations are likely to have unique but unidentified mechanisms that lead to excessive production of 8-OHdG.

Una visión personal de la endocrinología en Chile

In a short historical review of the outstanding changes occurred in the whole of endocrinology and particularly in Chile over the last 60 years -with the background of an infant mortality drop from 200 per thousand in 1940 to 8 per thousand today and a mean life expectancy increase from 42 to 76 years- the author outlines major achievements in this country. He comments on the use in former days of biological tests on urine extract to measure hormones for diagnostic procedures replaced by hormone determinations in blood by radioimmunoassays; today's medication with synthetic hormones instead of opotherapeutic preparations obtained from organ extracts; the identification of new hormones, receptors and new knowledge that enables us to understand the role of neurotransmitters and neuromodulators, the interaction of neurological, endocrine and immunological systems and the involvement of stress in various diseases. Finally the description of DNA and the international cooperative project to establish the human genome map with unpredictable potential applications in medicine. The author underlines the importance of collaborative work in all branches of medicine, often making cooperation more effective than competition. The enormous expansion of biological information demands that direct application of scientific knowledge to clinical medicine is prevented as being insufficient for an optimal clinical judgment, since a bio-psychosociological perspective of the patient and the doctor's clinical experience are essential factors in the doctor-patient relationship.

Serum thioredoxin elucidates the significance of serum ferritin as a marker of oxidative stress in chronic liver diseases.

Serum thioredoxin (TRX) levels have recently been established as an indicator of oxidative stress in various diseases. The aim of the present study was to clarify the clinical significance of serum ferritin in chronic liver diseases. Levels of ferritin, transferrin saturation (TS), aspartate aminotransferase (AST), and TRX were measured in the sera of patients with chronic hepatitis C (CH-C, n=92), chronic hepatitis B (CH-B, n=28), nonalcoholic fatty liver (FL, n=31), or alcoholic liver diseases (ALD, n=17). Serum TRX levels were evaluated with a recently established sandwich enzyme-linked immunosorbent assay kit. Serum TRX levels were significantly higher in CH-C, FL, and ALD than in healthy volunteers. A larger proportion of patients with CH-C, FL, and ALD had elevated levels of serum ferritin than CH-B. Serum ferritin levels were positively correlated with levels of TS, AST, and TRX in CH-C, but were merely correlated with TS values in CH-B. Ferritin levels were also well correlated with AST and TRX, but not with TS in FL and ALD. Oxidative stress, which was evaluated by measuring serum TRX, in addition to storage iron and hepatocyte damage is a cause of increasing serum ferritin levels in chronic liver diseases. An elevated serum ferritin level, which was correlated with TS, indicates that iron-induced oxidative stress contributes to CH-C. Elevated ferritin levels in FL and ALD may be mostly due to iron-unrelated stresses.

Targeting Sod by Gene and Protein Engineering and Inhibition of Free Radical Injury

Although oxygen toxicity of tissues can be decreased by a variety of antioxidants and some enzymes, such as SOD and catalase, their protective effect on tissue injury in various diseases are fairly small predominantly because of their unfavorable in vivo behavior. To minimize oxidative stress in various diseases, such as ischemic myocardial injury, circulatory disturbance and corneal inflammation, we synthesized three types of SOD derivatives by gene and protein engineering technique. One type of SOD (SM-SOD covalently linked with hydrophobic anions) circulates bound to albumin with a half life of 6 h and accumulates in tissues whose local pH is decreased. The other type of SOD (AC-SOD covalently linked with long chain fatty acids via the epsilon-amino group of lysyl residues) anchors onto membrane/lipid bilayers of various cells. The last type of SOD (HB-SOD synthesized by constructing a fusion gene coding human CuZn-type SOD and a C-terminal heparin-binding domain) binds to heparin-like proteoglycans on vascular endothelial cell surface. Intravenous administration of either SM-SOD or HB-SOD markedly inhibited postischemic reflow arrhythmias in the rat. When the left anterior descending artery was occluded permanently, about 65% of animals died within 30 min predominantly due to irreversible ventricular fibrillation; the motality of animals decreased to 15% by administering SM-SOD either before or after occlusion. Topically administered AC-SOD bound to the corneal epithelial cell surface and polymorphonuclear leukocytes and efficiently dismutated superoxide radicals at their cell surface. Thus, endotoxin-induced keratitis was inhibited markedly by topical instillation of AC-SOD.(ABSTRACT TRUNCATED AT 250 WORDS)