Kidney Transplant Recipients Show Limited Lung Diffusion Capacity but Similar Hydrogen Peroxide Exhalation as Healthy Matched Volunteers: A Pilot Study

Patients with end-stage chronic kidney disease show higher systemic oxidative stress and exhale more hydrogen peroxide (H2O2) than healthy controls. Kidney transplantation reduces oxidative stress and H2O2 production by blood polymorphonuclear leukocytes (PMNs). Kidney transplant recipients (KTRs) may be predisposed to an impairment of lung diffusing capacity due to chronic inflammation. Lung function and H2O2 concentration in the exhaled breath condensate (EBC) were compared in 20 KTRs with stable allograft function to 20 healthy matched controls. Serum interleukin eight (IL-8) and C-reactive protein (CRP), blood cell counts, and spirometry parameters did not differ between groups. However, KTRs showed lower total lung diffusing capacity for carbon monoxide, corrected for hemoglobin concentration (TLCOc), in comparison to healthy controls (92.1 ± 11.5% vs. 102.3 ± 11.9% of predicted, p = 0.009), but similar EBC H2O2 concentration (1.63 ± 0.52 vs. 1.77 ± 0.50 µmol/L, p = 0.30). The modality of pre-transplant renal replacement therapy had no effect on TLCOc and EBC H2O2. TLCOc did not correlate with time after transplantation. In this study, TLCOc was less reduced in KTRs in comparison to previous reports. We suggest this fact and the non-elevated H2O2 exhalation exhibited by KTRs, may result perhaps from the evolution of the immunosuppressive therapy.

Exhaled breath condensate: a comprehensive update

Since the late 1990s, a surge in interest in the analysis of exhaled breath condensate (EBC) resulted in the American Thoracic Society and European Respiratory Society (ATS/ERS) organising a Task Force in 2001 to develop guidelines on EBC collection and measurement of biomarkers. This Task Force published their guidelines in 2005 based on literature and expert opinions at that time, and multiple shortcomings and knowledge deficits were also identified. The clinical application of EBC collection and its biomarkers are currently still limited by several of these knowledge gaps, hence further guidelines for standardisation are required to ensure external validity. Using related articles produced since the publication of the ATS/ERS Task Force report, this paper attempts to provide a comprehensive update to the original guideline and review the methodological shortcomings identified. This review can hopefully serve as a yardstick for future studies involving this emerging clinical tool.

Diagnosis of breast cancer based on breath analysis: an emerging method

Breast cancer (BC) is the most commonly diagnosed malignancy and the second leading cause of the cancer-related deaths among females. Early diagnosis is one of the most important strategies to reduce breast cancer morbidity rate and improve the survival rate. However, early diagnosis of breast cancer is limited because the disease usually develops asymptomatically. Moreover, current screening techniques for breast cancer are always expensive, discomfort, and even harmful for patients, and furthermore, do not fulfill the requirements for reliable differentiation between breast cancer patients and healthy subjects. Breath analysis is non-invasive, painless, easy to perform and no risk to patients. Therefore, this innovative method provides a potentially useful approach to screen breast cancer. This review summarizes the scientific evidences related to breast cancer patients through detecting unique potential biomarkers in the exhaled breath, and the profile of breath biomarker for breast cancer clinical diagnosis.

Breath analysis of hydrogen peroxide as a diagnostic tool

The potential diagnostic significance of exhaled hydrogen peroxide (H(2)O(2)) in pulmonary and systemic disorders has received considerable interest over the last few decades. Despite large physiologic variability and low specificity, airway H(2)O(2) generation has been found to be consistently increased by inflammatory conditions. Furthermore, the level of exhaled H(2)O(2) has been associated with efficacy of treatment in various pulmonary diseases. To evaluate this potential biomarker, detection methods including standardization protocols have been developed. Despite these advances, more comprehensive and controlled studies are required. In this manuscript we review progress to date in the analytical measurement of exhaled H(2)O(2) and speculate on its potential clinical significance as a diagnostic tool.

Serum antioxidant capacity is preserved in peritoneal dialysis contrary to its robust depletion after hemodialysis and hemodiafiltration sessions

Renal replacement therapy (RRT) may differentially affect systemic generation of reactive oxygen species and depletion of antioxidant pools of low molecular weight molecules and proteins. This study was designed to assess the magnitude of the impairment of serum total antioxidant capacity (TAC) in relation to different RRT modalities. The study included patients on continuous ambulatory peritoneal dialysis (CAPD, N = 21), hemodialysis (HD, N = 21), hemodiafiltration (HDF, N = 20), and healthy controls (N = 33). TAC was assessed by the ferric reducing ability of plasma (FRAP) and with the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay. In CAPD patients, predialysis FRAP and DPPH were increased: 1.46 mM and 10.5% vs. control 1.19 mM and 7.2%, respectively (P < 0.001 in each). In HD and HDF patients, the FRAP and DPPH were significantly increased before and lowered after the RRT session (P < 0.05) if compared with healthy controls. During an HD session, FRAP was decreased from pre-HD 1.71 +/- 0.29 mM to post-HD 0.85 +/- 0.20 mM (P = 0.0001). The decrease of FRAP was lower during HDF (P < 0.05 vs. HD), it decreased from pre-HDF 1.41 +/- 0.43 mM to post-HDF 0.87 +/- 0.23 mM (P = 0.0001 vs. pre-HDF). The HD session decreased DPPH from the pre-HD median 10.3%, interquartile range (IR) 9.3-12.0% to post-HD 2.6% IR 2.3-3.1% (P < 0.0001). The adjustment of either urate or bilirubin up to pre-HD levels did not restore lowered post-HD levels of TAC. TAC remains preserved in CAPD, whereas the robust depletion of TAC, lower after HDF than HD sessions, cannot be attributed solely to the washout of dialyzable compounds.

Parameters of oxidative stress and echocardiographic indexes in patients on dialysis therapy

AIM

Quantity of oxidative stress (OS) is enhanced in every stage of chronic renal failure (CRF). OS and its effects on echocardiographic indexes in patients on hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) were evaluated.

MATERIALS AND METHODS

Thirty-nine patients on CAPD, 32 patients on HD, and 30 healthy individuals with similar demographic features were included. Patients with diabetes mellitus and chronic inflammatory diseases were excluded. Blood samples were collected to examine hematological and biochemical parameters and levels of malonyldialdehyde (MDA), glutathione peroxidase (GSH-px), and superoxide dismutase (SOD) after a 12-hour fasting period in the middle of dialysis week. OS parameters were compared with ejection fraction (EF), interventricular septum diameter (IVSd), left ventricular posterior wall diameter (LVPWd), and left atrium diameter (LAd) determined in M-mod echocardiographic examination.

RESULTS

No significant difference was observed between MDA and GSH-px levels of patients and control group; however, SOD levels of patients group were significantly lower (p<0.0001). SOD levels of patients on HD were lower than that of patients on CAPD (p=0.039). Negative correlation was detected between MDA and EF (r=-0.380, p=0.001); SOD has negative correlation with systolic blood pressure (r=-0.265, p=0.011), diastolic blood pressure (r=-0.230, p=0.028), phosphorus (r=-0.327, p=0.001), intact parathyroid hormone (iPTH) (r=-0.259, p=0.013), C-reactive protein (CRP) (r=-0.235, p=0.024), fibrinogen (r=-0.342, p=0.001), and total cholesterol (r=-0.249, p=0.017); and positive correlation with hemoglobin (r=0.414, p<0.001) and albumin (r=0.367, p<0.001). MDA was independently related with age (beta=-0.258, p=0.035), male gender (beta=-0.312, p=0.004), and EF (beta=-0.461, p<0.001). No correlation was determined between antioxidants and cardiac indexes.

CONCLUSION

SOD levels decreased significantly especially in patients on HD, and it was observed that lower levels of SOD would lead to OS in patients on HD and CAPD when compared to healthy individuals; MDA levels were independently influenced from EF.

Increased H2O2 level in exhaled breath condensate in primary breast cancer patients

PURPOSE

This study was designed to assess exhaled hydrogen peroxide (H(2)O(2)), blood serum antioxidant capacity, and tumor necrosis factor-alpha (TNFalpha) in primary breast cancer (PBC).

METHODS

The study included 34 consecutive, non-smoking PBC patients (aged 62.5 +/- 13.5 at surgery) prior to the treatments, qualified for modified radical mastectomy and not undergoing any adjuvant systemic therapy, and 33 healthy controls. The post surgery pathological assessment included tissue expression of estrogen (ER) and progesterone (PR) receptors, and epidermal growth factor receptor type 2 (HER-2/neu). Exhaled H(2)O(2) was determined fluorometrically in the exhaled breath condensate (EBC). Blood serum antioxidant capacity and TNFalpha levels were assessed with ferric reducing ability of plasma (FRAP) and ELISA immunoassay, respectively.

RESULTS

In PBC patients, 10 ER, 11 PR, and 9 HER-2/neu positive tumors were identified and HER-2/neu score was 2+ in 20% of all tumors. Median (Me) H(2)O(2) was increased up to 0.44 microM (interquartile range IR: 0.20-1.25 microM) compared with healthy control of 0.36 microM (IR: 0.12-0.48 microM; p < 0.05). The H(2)O(2) concentration in EBC was significantly correlated (tau = 0.27; p = 0.03) and increased in cases with nodal metastases (n = 12; p = 0.04). Serum TNFalpha was increased up to 51.7 +/- 21.0 pg/ml compared with controls 17.2 +/- 3.65 pg/ml (p < 0.05). FRAP was increased to 1.41 +/- 0.37 mM Fe(2+) compared with control 1.19 +/- 0.17 mM Fe(2+); (p = 0.006).

CONCLUSIONS

This is the first study to demonstrate increased H(2)O(2) in exhaled breath condensate in patients with localized breast malignancy and its relation with clinical severity.