Cytochrome P450 gender-related differences in response to hyperoxia in young CBA mice.

Cytochrome P450 monooxygenases (CYPs) represent large class of heme-containing enzymes that catalyze the metabolism of various endogenous and exogenous substrates. Although they are found in many tissues, the function of the particular subset of their isoforms does not appear to be the same. Many CYP genes exhibit sexually dimorphic expression, while others are sex-independent. Moreover, as a source of reactive oxygen species (ROS), P450 system is believed to play the important role in various pathological conditions and diseases. The aim of this study was to observe the effect of hyperoxia on oxidant/antioxidant status in the liver of young male and female mice and to determine whether the observed effects are associated with the expression of Heme oxygenase-1 (HO-1) and CYP genes associated with stress (Cyp1a1, Cyp1a2, Cyp2a5, and Cyp2e1) or stress and gender-related responses (Cyp2b9). In this study, we demonstrated gender-related effect of hyperoxia on oxidant/antioxidant status and on expression of certain P450 enzymes. Our results suggest that females are less susceptible to hyperoxia induced oxidative stress by two major mechanisms: upregulated expression of HO-1 genes and different expression of certain P450 enzymes. Therefore, our study could provide additional data of gender-dependent responses in susceptibility to oxidative stress, chemical toxicity and drug efficiency in treatment of diseases.

Cyp4a14 overexpression induced by hyperoxia in female CBA mice as a possible contributor of increased resistance to oxidative stress.

The beneficial effects of hyperoxia have been noted in treatment of several diseases and pathological states. However, the excessive production of ROS under hyperoxic conditions can directly damage cellular macromolecules if the imbalance in antioxidant status exists. Cytochrome P450 (Cyp) 4a14 has an important role in the metabolism of lipids and as a source of ROS in oxidative stress. This study investigated the oxidant/antioxidant status as a response to hyperoxia treatment in liver of young CBA/Hr mice of both sexes and whether the observed response is mediated by Cyp4a14 via PPAR isoforms in a sex-dependent manner. The overexpression of Cyp4a14, lack of both LPO and of 4-hydroxynonenal(HNE)-protein adducts revealed by immunohistochemical analysis in hyperoxia-treated females indicates their greater resistance to hyperoxia compared to males, which is parallelled to changes in PPARbeta/delta and PPARgamma expression. These results suggest the presence of sex-dependent changes in all investigated parameters, which points out sex-related susceptibility towards oxidative stress and hyperoxia treatment of various pathological conditions and diseases.

Dynorphin inhibits NEP activity in R1.1 mouse thymoma cells.

NEP/CALLA or CD10 is an endopeptidase (E.C. 3.4.24.11) that inactivates numerous neuropeptides, including dynorphin. Dynorphin is an endogenous opioid polypeptide that binds to kappa-opioid receptors with greatest affinity. R1.1 mouse thymoma cells highly express kappa-opioid receptors. In this study, on R1.1 cells, NEP activity was inhibited by kappa-opioid polypeptide dynorphin (10(-8)-10(-6) M) and by thiorphan (2 x 10(-4) M), a known inhibitor of NEP (30 min treatment). NEP inhibition by dynorphin was stronger than by thiorphan. A non-opioid opioid mechanism of action was mostly involved in this inhibition.

The expression of human corneal MMP-2, MMP-9, proMMP-13 and TIMP-1 in bullous keratopathy and keratoconus.

We aim to find a link between keratokonus (KC) and bullous keratopathy (BK), and extra cellular matrix re-modellation molecules. The activities of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), pro-matrix metalloproteinase-13 (proMMP-13) and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) were measured using immunoassay in three human corneal tissue layers (epithelium, stroma and endothelium) supernatants of the patients with KC and BK which underwent the perforative keratoplasty. MPP-2, MMP-9, proMMP-13 and TIMP-1 activity was detected in all samples. The epithelial layer showed significantly higher levels of MMP-9 and proMMP-13 in BK than in KC. Increased levels of MMP-2 (p=0.07) levels were found in bullous keratopathy compared to keratoconus patients. Epithelial TIMP-1 showed no significant difference in activity between KC and BK. All these findings suggest an active degradation of the extra-cellular matrix in epithelial corneal layer in Bullous Keratopathy. No difference in the concentration of MMP-2, MMP-9, proMMP-13 and TIMP-1 between KC and BK in corneal stroma and endothelium suggest that neither of these molecules play important role in KC or BK pathogenesis, at least not in stroma and endothelium.

Vascular endothelial growth factor in aqueous humor of patients with perforative eye injuries.

Considering that VEGF is the key factor for angiogenesis stimulation, we wanted to establish if VEGF level is increased in aqueous humor of patients with open globe eye injury. The study included 20 patients with open globe injury. During the surgery, aqueous humor samples were taken out and VEGF levels were measured by ELISA. VEGF levels were significantly higher in the aqueous humor of patients with open globe eye injury and uveitis, in patients with wound bigger than 2 mm and in patients where from injury to surgery passed more than 4 hours. VEGF levels were also higher, but not significantly, in patients with intrabulbar foreign body. Considering that VEGF levels were significantly higher in patients with open globe eye injury with uveitis, wound larger than 2 mm and in patients where from injury to surgery passed more than 4 hours, anti VEGF therapy might have application in these conditions.

Expression of vascular endothelial growth factor in proliferative diabetic retinopathy.

The study included 20 patients with diabetes mellitus type I (DM I) and 16 with type II (DM II) suffering from prolipherative diabetic retinopathy (PDR) for which they underwent vitrectomy. The quantity of VEGF and its receptors in the vitreous of investigated patients were measured by immunoassay and results compared between patients with DM I and II. The mean levels in the vitreous were significantly higher in diabetics with PDR and diabetes mellitus I (432.2 pg/mL, 1460.4 pg/mL and 1054.6 pg/mL) than in diabetics with PDR and diabetes mellitus II (147.5 pg/mL, 641.4 pg/mL and 448.5 pg/mL) and in control group (63.26 pg/mL). Considering that VEGF VEGFR1 and VEGFR2 levels were significantly higher in diabetics with PDR than in controls and that the patients with DM I had higher levels than with DM II, anti-VEGF therapy might be beneficial for diabetics with PDR, especially those with DM I.