Susceptibility Of Peripheral Blood Lymphocytes Research Articles

Magnesium suppresses in vivo oxidative stress and ex vivo DNA damage induced by protracted ACTH treatment in rats.

Oxidative stress, arising from disrupted balance between reactive oxygen/nitrogen species (ROS/RNS) and antioxidant defences, has been implicated in the pathogenesis of stress-related disorders. There is a growing body of evidence that supports the relationship between the activity of the hypothalamic-pituitary-adrenal (HPA) stress system, oxidative stress and magnesium (Mg) homeostasis. The present study aimed to explore the gap in our current understanding of antigenotoxic and protective effects of Mg supplementation against excessive ROS production in male rats during chronic treatment with adrenocorticotropic hormone (ACTH). Our findings show that exposure to exogenous ACTH (10μg/day, s.c., for 21 days), as one of the key mediators of the HPA axis and stress response, produced an increase in superoxide anion levels and a decrease in superoxide dismutase activity in plasma. We observed that Mg supplementation, starting seven days prior to ACTH treatment and lasting 28 days (300mg/L of drinking water, per os), abolished these effects in experimental animals. Moreover, our study reveals that ACTH increased the susceptibility of peripheral blood lymphocytes to ex vivo H2O2-induced total and high-level oxidative DNA damage, while Mg completely reversed these effects. Collectively, these results highlight the promising role of Mg in stress-related conditions accompanied by increased oxidative stress in animals and support further investigation using human dietary trials.

Genetic Instability in Lymphocytes is Associated With Blood Plasma Antioxidant Levels in Health Care Workers Occupationally Exposed to Ionizing Radiation.

Earlier reports have suggested that exposure to radiation at workplace may induce cytogenetic abnormalities. However, the association between plasma antioxidants and the cytogenetic abnormalities in these patients has not been elucidated till now. Hence, the present study was undertaken to determine the relationship between the cytogenetic abnormalities, plasma antioxidant system, and the radiation exposure levels in men who were occupationally exposed to ionizing radiation. The study included 134 male volunteers, among whom 83 were occupationally exposed to ionizing radiation. Incidence of micronuclei and chromosomal aberration was assessed in lymphocytes. Total and reduced glutathione (GSH), total antioxidant capacity (TAC), superoxide dismutase (SOD), and lipid peroxidation were assessed in the plasma. The micronuclei frequency and chromosomal aberrations were significantly higher in the exposed group in comparison to the nonexposed group (P < 0.01-0.0001). Similarly, GSH, TAC, and SOD in the blood plasma were significantly higher in the exposed group than the nonexposed group (P < 0.01-0.0001). However, the level of malondialdehyde, which is an indicator of lipid peroxidation, did not differ significantly between both the groups. Importantly, radiation absorbed dose exhibited a positive correlation with the incidence of micronuclei in blood lymphocytes but not with chromosomal aberrations. This study shows that the susceptibility of peripheral blood lymphocytes to chromosomal damage is associated with plasma antioxidant levels. Furthermore, increased levels of blood plasma GSH, TAC, and SOD in occupationally exposed individuals could be an adaptive measure in response to oxidative stress to protect somatic cell genetic integrity.

EPS06.9 Lung disease progression and inflammatory parameters in children with cystic fibrosis chronically colonized with Burkholderia cepacia complex

Objectives The aim of this study was to compare lung disease severity and inflammatory markers in cystic fibrosis (CF) pediatric patients chronically colonized with Burkholderia cepacia complex (Bcc) and those who were free of the pathogen. Methods 95 children (mean age 11.5 years) were enrolled into the study. Besides routine examination and pulmonary function tests (PFT) performing, sputum and plasma concentrations of cytokines (TNF-α, IFNγ, IL-4, IL-10, IL-17, TGF-b1) and in situ elastase levels were assayed with commercially available kits. Individual susceptibility of peripheral blood lymphocytes (PBL) to glucocorticoids was also evaluated. Results Paradoxically, the patients with Bcc infection (n = 43) demonstrated better PFT outcomes and higher Body Mass Indexes (BMI) compared to those of uninfected children (n = 52). In the same time multiple antibiotic allergies as well as glucose tolerance abnormalities were more common among the patients of Bcc group. We did not find significant differences for in situ inflammatory markers between CF patients with and without Bcc infection. At once marked reduction of circulating IL-17 and TGF-β1 as well as increased sensitivity of PBL to glucocorticoids have been revealed in the infected group. Conclusion The paradoxical association of chronic Bcc colonization with better PFT outcomes, higher BMI and down-regulated systemic inflammatory markers in CF children may relate to more aggressive antibiotic therapy as well as Bcc-induced alterations of host inflammatory response. Further studies are needed to better understand the specific nature of the host–pathogen interactions during chronic Bcc colonization.

Genomic instability in patients with autosomal-dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease (ADPKD) is a systemic disorder affecting multiple organs that results in renal and extrarenal cysts. Patients with ADPKD may have genomic instability, making them more vulnerable to developing cancer. This study aimed to investigate latent genomic instability in patients with ADPKD, using single-cell gel electrophoresis (comet assay). The susceptibility of peripheral blood lymphocytes to DNA damage induced by X-ray treatment (0.5 Gy) was tested in 20 patients with ADPKD using single-cell gel electrophoresis. The percentage of DNA in the comet tail (TDNA%) before and after irradiation was compared between patients with ADPKD and 20 sex- and age-matched healthy control subjects. Renal and extrarenal cysts were observed in patients with ADPKD. A significantly higher mean TDNA% was determined in patients with ADPKD compared with control subjects (8.85% versus 7.50%). After in vitro irradiation, DNA damage was significantly increased in all participants, but the increase was significantly greater in patients with ADPKD compared with control subjects. These data suggest that patients with ADPKD have genomic instability, which may trigger renal and extrarenal cyst formation.

Ocena ekspresji Fas i FasL na limfocytach krwi obwodowej chorych na raka krtani

The aim of the study was evaluation of Fas and FasL receptors’ expression on peripheral blood lymphocytes in patients with laryngeal cancer. The study was conducted in a group of 62 patients with different clinical stages of the disease. The study material consisted of the peripheral blood obtained from the studied population, from which T lymphocytes were isolated and incubated with monoclonal antibodies. To evaluate antigens’ expression, a FACS Galibur flow cytometre was used. The flow cytometry evaluated cells were labeled with fluorochrome-conjugated monoclonal antibodies. Obtained results were compared with the measurements taken in 20 healthy individuals who constituted the control group. In the conducted study a significant decrease in the Fas and FasL receptors’ expression on CD+ lymphocytes was found in comparison with the expression of these proteins observed in the control group. Moreover, a higher level of Fas expression was observed on the peripheral blood lymphocytes of patients with stage I clinical advancement of laryngeal cancer in comparison with those who had more advanced stages of the disease (Groups II, III, IV), which may be indicative of higher activation and susceptibility of peripheral blood lymphocytes to apoptosis in patients with the early stage of the disease. A negative (reverse) correlation was also found between Fas and FasL receptors’ expression and the organ advancement of laryngeal cancer, which may provide further evidence that together with the progress of the disease the susceptibility of peripheral blood lymphocytes to apoptosis decreases.

Noninvasive Prediction of Prostatic DNA Damage by Oxidative Stress Challenge of Peripheral Blood Lymphocytes

To move closer to the goal of individualized risk prediction for prostate cancer, we used an in vivo canine model to evaluate whether the susceptibility of peripheral blood lymphocytes (PBLs) to oxidative stress-induced DNA damage could identify those individuals with the highest prostatic DNA damage. This hypothesis was tested in a population of 69 elderly male beagle dogs after they had completed a 7-month randomized feeding trial to achieve the broad range of dietary selenium status observed in U.S. men. The alkaline Comet assay was used to directly compare the extent of DNA damage in PBLs with prostatic DNA damage in each dog. Using stepwise logistic regression, the sensitivity of PBLs to oxidative stress challenge with hydrogen peroxide (H(2)O(2)) predicted dogs in the highest tertile of prostatic DNA damage. Dogs with PBLs highly sensitive to H(2)O(2) were 7.6 times [95% confidence interval (95% CI), 1.5-38.3] more likely to have high prostatic DNA damage than those in the H(2)O(2)-resistant group. This risk stratification was observed in multivariate analysis that considered other factors that might influence DNA damage, such as age, toenail selenium concentration, and serum testosterone concentration. Our data show that the sensitivity of PBLs to oxidative stress challenge, but not endogenous DNA damage in PBLs, provides a noninvasive surrogate marker for prostatic DNA damage. These findings lend support to the concept that oxidative stress contributes to genotoxic damage, and that oxidative stress challenge may stratify men for prostate cancer risk.

Anti-retroviral therapy reverses HIV-associated abnormalities in lymphocyte apoptosis.

The objective of this study was to assess the role of anti-retroviral therapy (ART) on the susceptibility of peripheral blood lymphocytes (PBL) from HIV-1-infected individuals to activation-induced apoptosis and in comparison with changes in CD4 lymphocyte counts. Eleven symptomatic HIV+ patients were studied. Ex vivo apoptosis was measured in phytohaemagglutinin (PHA)-stimulated PBL and CD4 subsets by flow cytometry, at baseline and after 1 month (4-6 weeks) and 2/3 months of ART. Six patients had extended studies of the effects of therapy to a maximum of 21 months. Lymphocyte apoptosis was significantly elevated in HIV+ patients at baseline (median 22% compared with 7.5% in HIV- risk-matched controls; P < 0.05). This decreased to control levels on ART (7.4% at 4-6 weeks, P < 0.01, and 6.2% at 8-12 weeks, P < 0.05, compared with baseline). Similar changes occurred in the CD4+ subpopulation. The decrease in apoptosis was maintained for several months, but the effect was rapidly lost if ART was discontinued. CD4 counts showed a reciprocal relationship to changes in apoptosis. The association of changes in apoptosis with those in CD4 counts suggests a link between programmed cell death and lymphocyte depletion. Apoptosis reduced in some individuals without any reduction in viral load, suggesting apoptosis may be influenced by factors in addition to the overall extent of HIV replication.