Alterations In Stress Biomarkers Research Articles

Influence of Mild Chronic Stress and Social Isolation on Acute Ozone-Induced Alterations in Stress Biomarkers and Brain-Region-Specific Gene Expression in Male Wistar-Kyoto Rats.

Individuals with psychosocial stress often experience an exaggerated response to air pollutants. Ozone (O3) exposure has been associated with the activation of the neuroendocrine stress-response system. We hypothesized that preexistent mild chronic stress plus social isolation (CS), or social isolation (SI) alone, would exacerbate the acute effects of O3 exposure on the circulating adrenal-derived stress hormones, and the expression of the genes regulating glucocorticoid stress signaling via an altered stress adaptation in a brain-region-specific manner. Male Wistar-Kyoto rats (5 weeks old) were socially isolated, plus were subjected to either CS (noise, confinement, fear, uncomfortable living, hectic activity, and single housing), SI (single housing only, restricted handling and no enrichment) or no stress (NS; double housing, frequent handling and enrichment provided) for 8 weeks. The rats were then exposed to either air or O3 (0.8 ppm for 4 h), and the samples were collected immediately after. The indicators of sympathetic and hypothalamic-pituitary axis (HPA) activation (i.e., epinephrine, corticosterone, and lymphopenia) increased with O3 exposure, but there were no effects from CS or SI, except for the depletion of serum BDNF. CS and SI revealed small changes in brain-region-specific glucocorticoid-signaling-associated markers of gene expression in the air-exposed rats (hypothalamic Nr3c1, Nr3c2 Hsp90aa1, Hspa4 and Cnr1 inhibition in SI; hippocampal HSP90aa1 increase in SI; and inhibition of the bed nucleus of the stria terminalis (BNST) Cnr1 in CS). Gene expression across all brain regions was altered by O3, reflective of glucocorticoid signaling effects, such as Fkbp5 in NS, CS and SI. The SI effects on Fkbp5 were greatest for SI in BNST. O3 increased Cnr2 expression in the hypothalamus and olfactory bulbs of the NS and SI groups. O3, in all stress conditions, generally inhibited the expression of Nr3c1 in all brain regions, Nr3c2 in the hippocampus and hypothalamus and Bdnf in the hippocampus. SI, in general, showed slightly greater O3-induced changes when compared to NS and CS. Serum metabolomics revealed increased sphingomyelins in the air-exposed SI and O3-exposed NS, with underlying SI dampening some of the O3-induced changes. These results suggest a potential link between preexistent SI and acute O3-induced increases in the circulating adrenal-derived stress hormones and brain-region-specific gene expression changes in glucocorticoid signaling, which may partly underlie the stress dynamic in those with long-term SI.

Racial discrimination and biological dysregulation among Indigenous adults: The role of culture

Abstract Background Racial discrimination is an ongoing social concern that requires public health solidarity to address. Indigenous peoples in many countries report high levels of discrimination across a variety of life domains, particularly when they migrate into urban centres for school or work. Discrimination has wide-ranging impacts that go beyond mental distress to include alterations in stress biomarkers across multiple systems. This study examined the impacts of discrimination on multisystem biological dysregulation among urban Indigenous adults in Canada, operationalized through allostatic load; and the role that Indigenous cultural continuity might play in resilience. Methods This cross-sectional study collected data from 150 Indigenous adults attending university in a small city in western Canada between 2015 and 2017 (M age: 28 years). Allostatic load (AL) was measured as a composite of 7 biomarkers assessing neuroendocrine, cardiovascular, metabolic, and immune system function. Bias-corrected and accelerated bootstrapped linear regression models examined associations adjusted for confounders. Results Past-year discrimination was significantly and linearly associated with increased AL adjusting for age and income (B = 0.17, p = 0.02). Among adults with low cultural continuity, past-year discrimination was associated with AL in models adjusted for age and child discrimination (B = 0.17, p = 0.01), with past-year discrimination and the full model explaining 24% and 41% of the variance in AL; respectively. Among adults with high cultural continuity, past-year discrimination was not associated with AL, and the full model explained 1% of the variance in AL. Conclusions Past-year racial discrimination was an adverse event capable of influencing multisystem biological dysregulation among Indigenous adults, independent of age and income. Indigenous cultural continuity may promote biological resilience against racism within this population. Key messages Racial discrimination was associated with multisystem biological dysregulation among urban Indigenous adults, controlling for age and income. Indigenous cultural continuity buffered the impact of discrimination on biological health.

Evidence for the Important Role of Oxidative Stress in the Pathogenesis of Acne.

Acne vulgaris is a common inflammatory skin disorder which is recognizable by dermatological lesions and scars. In addition to some pathogenetic factors such as hyperkeratinization, upregulated sebum secretion, and immunoinflammatory reactions, recent studies have also connected oxidative stress to the pathogenesis of acne vulgaris. In this article, we will briefly review clinical studies that interrogated alterations in oxidative stress biomarkers by a systematic search conducted in PubMed, Web of Science, and Scopus using "acne", "oxidative stress", and "reactive oxygen species" keywords. Overall, studies have shown that oxidative biomarkers (e.g. lipid peroxidation final products) are higher in acne vulgaris lesions. A significant positive correlation has also been noted between acne severity and oxidative biomarkers. In contrast, diminished levels of antioxidant enzymes (e.g. superoxide dismutase and catalase) have been observed in acne. We propose four probable mechanisms for the role of reactive oxygen species (ROS) in acne pathogenesis. We believe that ROS can contribute significantly to the acne vulgaris pathobiology via toll-like receptor (TLR), peroxisome proliferator-activated receptor (PPAR), mTOR pathway, and innate immune system, resulting in inflammation by alterations in the generation of several proinflammatory cytokines including IL-1, IL-8, and TNF-α.

Nanosilver toxicity in gills of a neotropical fish: Metal accumulation, oxidative stress, histopathology and other physiological effects

The widespread and increasing use of silver nanoparticles (AgNP) as biocide results in an unknown release into the aquatic environment. In order to contribute to the understanding of their potential toxicity, the aim of this study was to analyze branchial multiple biomarkers on the neotropical fish Prochilodus lineatus. We exposed fish to sublethal AgNP concentrations: 0 (control), 2.5 and 25.0µgL−1. After 5 and 15 days, we analyzed in gills total Ag accumulation, oxidative stress markers (antioxidant enzymes, lipid peroxidation and antioxidant capacity against peroxyl radicals), aspartate and alanine aminotransferases activities (ALT, AST) and histopathologies (morphometric analysis, proportion of the secondary lamellae available for gas exchange, reaction indexes, and organ index -Igills-) that included mucus cell count (MCc). The Ag accumulation after 15 days was five times higher than after 5 days in the case of 25.0μg AgNP L−1-exposure. Regarding oxidative stress, all enzymes activities were inhibited after 5 days at both AgNP concentrations. ALT activity decreased and a reduction in the antioxidant capacity was evidenced after 2.5µg AgNP L−1 and 15 days. LPO levels and AST activity increased after the highest time of exposure and AgNP concentration, and the same occurred with Igills. MCc increased after 15 days at both AgNP concentrations. The results confirmed that the presence of low AgNP concentrations, in short and subchronic exposures, generates alterations in stress biomarkers and in the structure of this vital organ that are the gills.

Protective effect of Ipomoea carnea Jacq leaves extracts on streptozotocin-induced oxidative stress in rats

Objective: Imbalance between the concentrations of oxidant and antioxidants in mammalian cells leads to oxidative stress. The present study aimed to evaluate the protective effect of Ipomoea carnea Jacq leaves extracts on streptozotocin (STZ)-induced oxidative stress in rats. Methods: Alterations in stress biomarkers like activities of superoxide dismutase, catalase, glutathione peroxidase, and levels of blood glutathione and malondialdehyde in experimental groups administered with STZ alone and along with aqueous or alcoholic extracts of I.carnea were determined. Results: Single intra-peritoneal administration of STZ (60 mg/kg) caused significant decrease in activities of superoxide dismutase, catalase, glutathione peroxidase, and blood glutathione levels while malondialdehyde level as an indicative of oxidative stress significant increased. Administration of I.carnea extracts at the dose rate of 500 mg/kg body weight through oral gavage continuously for 3 weeks in STZ-treated group reduced malondialdehyde level significantly and increased activities of superoxide dismutase, catalase, glutathione peroxidase, and blood glutathione level as compared to STZ alone treated rats; however, the values of antioxidants remain still lower in comparison to normal control rats. Conclusion: In the present STZ-diabetes model of rats, alcoholic extract of I.carnea leaves have more potent efficacy in restoring the enzymatic and non-enzymatic components of antioxidant system of rats as than the aqueous extract.

λ-Cyhalothrin and cypermethrin induce stress in the freshwater muddy fish, Clarias batrachus

In order to understand the level of health risk posed by pyrethroid insecticides with strong soil-binding properties to freshwater fish, specifically living in muddy region of aquatic bodies, changes were examined in different biochemical stress markers in a freshwater muddy fish, Clarias batrachus, exposed to pyrethroid insecticides, cypermethrin and λ-cyhalothrin, in low sub-acute concentrations parts per million (ppm) for 96 hr. Data showed significant increase in levels of lipid peroxidation and in activities of lactate dehydrogenase, acid, and alkaline phosphatases along with marked decline in the specific activity of acetylcholinesterase in a concentration-dependent manner. The marked alterations in stress biomarkers indicate that pyrethroids induce significant stress in C. batrachus. This risk assessment study draws attention towards the potential health risk of freshwater muddy fish, which are continuously being exposed to the high concentrations of such insecticides accumulated as runoff in the muddy bottom of aquatic bodies.