L-tyrosine and nitric oxide synergize to prevent cytotoxic effects of superoxide

Exploratory investigation of plasma metabolomics in human lung adenocarcinoma

Globally lung cancer is common among males and recently also noted with increasing incidences in females, especially adenocarcinoma. Further, most lung cancers are not easily detected until the late stage. Metabolic profiling of plasma low molecular weight metabolites may help unveil the complex pathophysiological changes during early lung adenocarcinoma development. Here we used a combination of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) methods to investigate the metabolic signatures in the plasma of 31 stage I human lung adenocarcinoma patients and 28 healthy controls. The metabolic profiles were assayed using orthogonal projections to latent structures discriminant analysis (OPLS-DA), and were further analyzed to identify the associated marker metabolites. The OPLS-DA models derived from both GC-MS and LC-MS showed significant discriminations in metabolic profiles between cases and healthy controls. It was found that around 37 metabolites contributed to the differences. The alterations of these metabolites implied disturbances in amino acids, lipids, fatty acids and glutaminolysis metabolism in human lung adenocarcinoma, even after removal of influencing factors such as age, gender and smoking habits. Of particular interest, the sex hormone metabolic pathway involving the sulfate conjugate of testosterone, androsterone and pregnenolone was found to be disturbed considerably. All these metabolic perturbations occur at an early stage of lung adenocarcinoma and thus could act as biomarkers for its early diagnosis. These exploratory findings suggest that integration of two sensitive and complementary metabolomic approaches enables a comprehensive metabolite profiling for human lung adenocarcinoma, although a more extensive study is needed to confirm the findings.

Metabolic profiling of plasma from benign and malignant pulmonary nodules patients using mass spectrometry-based metabolomics

Solitary pulmonary nodule (SPN or coin lesion) is a mass in the lung and can be commonly found in chest X-rays or computerized tomography (CT) scans. However, despite the advancement of imaging technologies, it is still difficult to distinguish malignant cancer from benign SPNs. Here we investigated the metabolic profiling of patients with benign and malignant pulmonary nodules. A combination of gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) was used to profile the plasma metabolites in 17 patients with malignant SPNs, 15 patients with benign SPNs and 20 healthy controls. The metabolic profiles were assayed using OPLS-DA, and further analyzed to identify marker metabolites related to diseases. Both GC/MS- and LC/MS-derived models showed clear discriminations in metabolic profiles among three groups. It was found that 63 metabolites (12 from GC/MS, 51 from LC/MS) contributed to the differences. Of these, 48 metabolites showed same change trend in both malignant and benign SPNs as compared with healthy controls, indicating some common pathways including inflammation and oxidative injury shared by two diseases. In contrast, 14 metabolites constituted distinct profiles that differentiated malignant from benign SPNs, which might be a unique biochemical feature associated with lung cancer. Overall, our data suggested that integration of two highly sensitive and complementary metabolomics platforms could enable a comprehensive metabolic profiling and assist in discrimination malignant from benign SPNs.

The nitric oxide donor, V-PYRRO/NO, protects against acetaminophen-induced nephrotoxicity in mice

The nitric oxide (NO) donor, O(2)-vinyl 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (V-PYRRO/NO), is metabolized by P450 enzymes to release NO in the liver and possibly other tissues. V-PYRRO/NO has been shown to be hepatoprotective, but little is known about its effect in the kidney, another organ rich in P450s. Thus, mice were given V-PYRRO/NO (0.4-5.4 mg/ml, 8 microl/h) before and/or after a nephrotoxic dose of acetaminophen (APAP; 600 mg/kg, i.p.) to examine its nephroprotective effects. V-PYRRO/NO administration significantly reduced APAP-induced nephrotoxicity in a dose- and time-dependent manner, as evidenced by mitigation of increased blood urea nitrogen levels and by amelioration of renal pathology, specifically interstitial congestion, proximal tubular cell degeneration and necrosis. The best protection was observed at the highest dose (5.4 mg/ml) and with V-PYRRO/NO pretreatment (4-16 h). Implanting V-PYRRO/NO pumps simultaneously with APAP also attenuated APAP nephrotoxicity. The protection is probably not due to a decreased APAP toxication metabolism, as similar depletion of renal glutathione levels was observed regardless of V-PYRRO/NO treatment. APAP-induced renal lipid peroxidation was reduced by V-PYRRO/NO, as determined by the concentrations of hydroxynonenals and malondialdehyde. In summary, this study demonstrates that the NO donor V-PYRRO/NO is effective in blocking APAP-induced nephrotoxicity in mice. The protection is probably due to multiple mechanisms involving attenuation of APAP-induced congestion and lipid peroxidation in the kidney.