The aim of the present study was to describe some of the oxidative stress parameters in bitches suffering from spontaneously occurring mammary gland tumours. The experiment involved 28 bitches which had mammary gland tumours removed surgically (15 bitches with malignant tumour and 13 with benign tumour) as well as 10 clinically healthy bitches. The activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in haemolysates of erythrocytes derived from the animals. The concentrations of thiobarbituric acid reactive substances (TBARS), as well as -SH groups, were determined in blood plasma. GSH-Px activity was significantly higher in the malignant tumour group than in healthy animals. SOD activity was significantly higher in animals with tumours compared with the control group. Activities of both enzymes were higher in animals with malignant tumours than in benign groups, but the differences were not statistically significant. The concentrations of TBARS and -SH groups were similar in all examined groups. The increase of antioxidative enzyme activities in these animals may suggest the activation of antioxidative defence mechanisms in mammary gland carcinogenesis. Moreover, it might indicate the participation of oxidative stress in malignancies. Further experiments involving more animals, with more frequent sample collection and the use of other oxidative stress markers are necessary.

BACKGROUND Guidelines recommend nonstatin lipid-lowering agents in patients at very high risk for major adverse cardiovascular events (MACE) if low-density lipoprotein cholesterol (LDL-C) remains ≥70 mg/dL on maximum tolerated statin treatment. It is uncertain if this approach benefits patients with LDL-C near 70 mg/dL. Lipoprotein(a) levels may influence residual risk. OBJECTIVES In a post hoc analysis of the ODYSSEY Outcomes (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) trial, the authors evaluated the benefit of adding the proprotein subtilisin/kexin type 9 inhibitor alirocumab to optimized statin treatment in patients with LDL-C levels near 70 mg/dL. Effects were evaluated according to concurrent lipoprotein(a) levels. METHODS ODYSSEY Outcomes compared alirocumab with placebo in 18,924 patients with recent acute coronary syndromes receiving optimized statin treatment. In 4,351 patients (23.0%), screening or randomization LDL-C was <70 mg/dL (median 69.4 mg/dL; interquartile range: 64.3–74.0 mg/dL); in 14,573 patients (77.0%), both determinations were ≥70 mg/dL (median 94.0 mg/dL; interquartile range: 83.2–111.0 mg/dL). RESULTS In the lower LDL-C subgroup, MACE rates were 4.2 and 3.1 per 100 patient-years among placebo-treated patients with baseline lipoprotein(a) greater than or less than or equal to the median (13.7 mg/dL). Corresponding adjusted treatment hazard ratios were 0.68 (95% confidence interval [Cl]: 0.52–0.90) and 1.11 (95% Cl: 0.83–1.49), with treatment-lipoprotein(a) interaction on MACE ( P interaction = 0.017). In the higher LDL-C subgroup, MACE rates were 4.7 and 3.8 per 100 patient-years among placebo-treated patients with lipoprotein(a) >13.7 mg/dL or ≤13.7 mg/dL; corresponding adjusted treatment hazard ratios were 0.82 (95% Cl: 0.72–0.92) and 0.89 (95% Cl: 0.75–1.06), with P interaction = 0.43. CONCLUSIONS In patients with recent acute coronary syndromes and LDL-C near 70 mg/dL on optimized statin therapy, proprotein subtilisin/kexin type 9 inhibition provides incremental clinical benefit only when lipoprotein(a) concentration is at least mildly elevated. (ODYSSEY Outcomes: Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab; NCT01663402 )

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