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Oxidative stress, DNA damage and repair in heart failure patients after implantation of continuous flow left ventricular assist devices.

Mondal NK, Sorensen E, Hiivala N, Feller E, Griffith B, Wu ZJ - Int J Med Sci (2013)

Bottom Line: Levels of ROS and oxLDL were significantly higher in HF patients with LVAD than baseline as well as the control group; moreover, SOD levels were decreased with increasing post-operative periods.All the changes indicated enhanced oxidative stress among LVAD recipients.Significantly higher γ-H2AX foci in lymphocytes confirmed DNA double strand breaks in LVAD recipients. γ-H2AX foci numbers in lymphocytes were positively correlated with the ROS and oxLDL and negatively with SOD levels (p<0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Artificial Organ Lab, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.

ABSTRACT

Objective: To study the status of oxidative stress and DNA damage repair in circulating blood leukocytes of heart failure patients supported by continuous flow left ventricular assist devices (LVADs).

Materials and methods: Ten HF patients implanted with LVAD as bridge to transplant or destination therapy were enrolled in the study and 10 age and sex matched volunteers were recruited as the study control. Reactive oxygen species (ROS) in blood leukocytes and superoxide dismutase (SOD) in erythrocytes were measured by flow cytometry/immunofluorescence microscopy and spectrophotometry, respectively. ELISA was used to measure oxidized low density lipoproteins (oxLDL) in plasma. Markers of DNA damage (γ-H2AX) and repairs (Mre11, DNA ligase IV, Ku70, and Ku80) were quantified in blood lymphocytes by immunocytochemistry.

Results: Levels of ROS and oxLDL were significantly higher in HF patients with LVAD than baseline as well as the control group; moreover, SOD levels were decreased with increasing post-operative periods. All the changes indicated enhanced oxidative stress among LVAD recipients. Significantly higher γ-H2AX foci in lymphocytes confirmed DNA double strand breaks in LVAD recipients. γ-H2AX foci numbers in lymphocytes were positively correlated with the ROS and oxLDL and negatively with SOD levels (p<0.0001). Expressions of DNA ligase IV, Ku70 and Ku80 proteins were highest after one week and Mre11 protein after 3 months of LVAD transplantation; indicated abnormal DNA repair.

Conclusions: The study, for the first time shows that, continuous flow LVAD implanted HF patients not only exhibit elevated oxidative stress and DNA damage in blood leukocytes but also have abnormalities in DNA repair pathways.

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Immunofluorescence microscopy showing Mre-11 foci formation (red) in nuclei of blood lymphocytes of control, pre-operative and post-operative samples. Note highest number of foci in nuclei of LVAD recipients after three month of implantation (POD-3M). Magnification × 1,000.
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Figure 4: Immunofluorescence microscopy showing Mre-11 foci formation (red) in nuclei of blood lymphocytes of control, pre-operative and post-operative samples. Note highest number of foci in nuclei of LVAD recipients after three month of implantation (POD-3M). Magnification × 1,000.

Mentions: Increased Mre-11 foci count in nuclei of blood lymphocytes indicates accelerated DNA repair either via homologous recombination (HR) or non-homologous end joining (NHEJ) pathways (Figure 4, Table 3). The mean γ-H2AX foci numbers positively correlated with the post-operative time after LVAD implantation (Spearman's ρ= 0.4835, p < 0.01). Other proteins (DNA ligase IV, Ku70 and Ku80) that help to repair double strand break exclusively via NHEJ pathway was also higher as the percent positive nuclei of blood lymphocytes significantly increased in pre-operative blood of the HF patients than the healthy control subjects. Moreover these proteins expression became highest at POD-1W after LVAD implantation and then decreased thereafter (Table 3).


Oxidative stress, DNA damage and repair in heart failure patients after implantation of continuous flow left ventricular assist devices.

Mondal NK, Sorensen E, Hiivala N, Feller E, Griffith B, Wu ZJ - Int J Med Sci (2013)

Immunofluorescence microscopy showing Mre-11 foci formation (red) in nuclei of blood lymphocytes of control, pre-operative and post-operative samples. Note highest number of foci in nuclei of LVAD recipients after three month of implantation (POD-3M). Magnification × 1,000.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675502&req=5

Figure 4: Immunofluorescence microscopy showing Mre-11 foci formation (red) in nuclei of blood lymphocytes of control, pre-operative and post-operative samples. Note highest number of foci in nuclei of LVAD recipients after three month of implantation (POD-3M). Magnification × 1,000.
Mentions: Increased Mre-11 foci count in nuclei of blood lymphocytes indicates accelerated DNA repair either via homologous recombination (HR) or non-homologous end joining (NHEJ) pathways (Figure 4, Table 3). The mean γ-H2AX foci numbers positively correlated with the post-operative time after LVAD implantation (Spearman's ρ= 0.4835, p < 0.01). Other proteins (DNA ligase IV, Ku70 and Ku80) that help to repair double strand break exclusively via NHEJ pathway was also higher as the percent positive nuclei of blood lymphocytes significantly increased in pre-operative blood of the HF patients than the healthy control subjects. Moreover these proteins expression became highest at POD-1W after LVAD implantation and then decreased thereafter (Table 3).

Bottom Line: Levels of ROS and oxLDL were significantly higher in HF patients with LVAD than baseline as well as the control group; moreover, SOD levels were decreased with increasing post-operative periods.All the changes indicated enhanced oxidative stress among LVAD recipients.Significantly higher γ-H2AX foci in lymphocytes confirmed DNA double strand breaks in LVAD recipients. γ-H2AX foci numbers in lymphocytes were positively correlated with the ROS and oxLDL and negatively with SOD levels (p<0.0001).

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Artificial Organ Lab, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.

ABSTRACT

Objective: To study the status of oxidative stress and DNA damage repair in circulating blood leukocytes of heart failure patients supported by continuous flow left ventricular assist devices (LVADs).

Materials and methods: Ten HF patients implanted with LVAD as bridge to transplant or destination therapy were enrolled in the study and 10 age and sex matched volunteers were recruited as the study control. Reactive oxygen species (ROS) in blood leukocytes and superoxide dismutase (SOD) in erythrocytes were measured by flow cytometry/immunofluorescence microscopy and spectrophotometry, respectively. ELISA was used to measure oxidized low density lipoproteins (oxLDL) in plasma. Markers of DNA damage (γ-H2AX) and repairs (Mre11, DNA ligase IV, Ku70, and Ku80) were quantified in blood lymphocytes by immunocytochemistry.

Results: Levels of ROS and oxLDL were significantly higher in HF patients with LVAD than baseline as well as the control group; moreover, SOD levels were decreased with increasing post-operative periods. All the changes indicated enhanced oxidative stress among LVAD recipients. Significantly higher γ-H2AX foci in lymphocytes confirmed DNA double strand breaks in LVAD recipients. γ-H2AX foci numbers in lymphocytes were positively correlated with the ROS and oxLDL and negatively with SOD levels (p<0.0001). Expressions of DNA ligase IV, Ku70 and Ku80 proteins were highest after one week and Mre11 protein after 3 months of LVAD transplantation; indicated abnormal DNA repair.

Conclusions: The study, for the first time shows that, continuous flow LVAD implanted HF patients not only exhibit elevated oxidative stress and DNA damage in blood leukocytes but also have abnormalities in DNA repair pathways.

Show MeSH
Related in: MedlinePlus