Kamelija Žarković

4-HYDROXYNONENAL AS A SECOND MESSENGER OF FREE RADICALS AND GROWTH MODIFYING FACTOR

Immunohistochemical analysis of the distribution of the lipid peroxidation product 4-hydroxynonenal (HNE) in the brain of baboons exposed to experimental hemorrhagic traumatic shock or sepsis showed that systemic oxidative stress and the thereby generated HNE affect the blood:brain barrier and the regulation of cerebral blood flow determining secondary brain damage. Similarly, HNE was determined during ischemia in the brain blood vessels of rats exposed to ischemia/reperfusion injury of the brain. After reperfusion, HNE disappeared from the blood vessels but remained in neurones and in glial cells. Since HNE modulates cell proliferation and differentiation (including proto-oncogene expression), it is postulated that HNE might have prominent local and systemic effects that are not only harmful but beneficial, too, determining the outcome of various pathophysiological conditions based on oxidative stress.

Comparison of the values of basic fibroblast growth factor determined by an immunoassay in the sera of patients with traumatic brain injury and enhanced osteogenesis and the effects of the same sera on the fibroblast growth in vitro.

In patients with severe traumatic brain injury, the early healing of fractures is accompanied by hypertrophic callus formation or heterotopic ossifications, which might even result in ankylosis of the affected joints. Analysis of the sera of patients with traumatic brain injury revealed post-traumatic dynamic changes of basic fibroblast growth factor immunoreactivity, similar to those observed during fracture healing associated with enhanced osteogenesis. The aim of this study was to determine whether such changes in basic fibroblast growth factor concentrations could be related to the phenomenon of enhanced osteogenesis. Basic fibroblast growth factor immunoreactivity was determined (using an IEMA kit) in the sera of patients with traumatic brain injury and bone fractures (n = 8) and in the sera of patients with either traumatic brain injury alone (n = 10) or bone fractures alone (n = 7), and the effects of these sera on L929 fibroblast growth were analysed in vitro. The results did not prove a causative relationship between the changes of basic fibroblast growth factor immunoreactivity and in vitro growth promoting effects of the sera. However, it is apparent that, in addition to changes in the growth-promoting activity and basic fibroblast growth factor concentration of serum, other as yet unknown post-traumatic changes can cause enhanced osteogenesis.

Brain MRI abnormalities in ataxia-telangiectasia.

Background:Ataxia-telangiectasia (AT) is a rare autosomal recessive disorder, initially characterized by normal brain magnetic resonance imaging (MRI). Case report:In a 34-year-old woman patient with AT, MRI revealed extensive and diffuse white matter dismyelination, T1 and T2 hypointense lesions, T1 hypointense but T2 hyperintense lesions, and numerous dilated telangiectases upon gadolinium enhancement. Discussion:In our patient, brain MRI confirmed extensive extracerebellar lesions in AT. Conclusion:Our report broadens the spectrum of brain MRI abnormalities in AT and supports the hypothesis on cerebrovascular abnormalities occurring in later stages of AT.

Lipid mediators involved in the oxidative stress and antioxidant defence of human lung cancer cells.

Background The oxidative modifications of bioactive macromolecules have important roles in carcinogenesis. Of particular interest are lipid peroxidation products, which are involved in the activation of Nrf2 and endocannabinoids that affect cancer progression. Methods In lung cancer tissues (squamous cell lung carcinoma - SCC and adenocarcinoma - AC), the glutathione peroxidase and catalase activity and glutathione level, together with the expression of Nrf2 and its activators/inhibitors were estimated. The oxidative modifications of DNA (8-hydroxy-2′-deoxyguanosine and N7-methylguanine), endocannabinoids (anandamide and 2- arachidonylglyceriol), their receptors (CB1/2, TRV1, GPR55), phospholipid fatty acids (arachidonic, linoleic and docosahexaenoic), and reactive aldehydes (4-hydroxynonenal, 4-oxononenal and malondialdehyde) were determined. Results Tumour tissues showed lower antioxidant capacity than healthy tissues, which was accompanied by lower levels of fatty acids and higher levels of reactive aldehydes. Disturbances in antioxidant capacity and enhanced DNA oxidative modifications were observed in 88% of AC patients and 81% of SCC patients. The 4-hydroxynonenal-Histidine adducts were detected in the necrotic and stromal cells in all tumours. These findings were associated with the enhanced Nrf2 activity, especially in AC. The strong difference between the cancer subtypes was evident in the levels of endocannabinoids, with an increase in 89% of SCC and a decrease in 85% of AC patients being observed. Additionally, the increase in the expression of CB1/2 receptors was observed only in 82% of AC, while the expression of VR1 and GPR55 was enhanced in 79% of SCC and 82% of AC patients. Conclusions This study shows significant differences in the redox status, Nrf2 pathway and endocannabinoid system between SCC and AC tissues. Understanding the relation between the various lipid mediators and antioxidants in different lung cancer subtypes may be beginning for further research on the effective anticancer therapy.

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

Abstract 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 PPARβ/δ and PPARγ 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.

Antitumor effect of Croatian propolis as a consequence of diverse sex-related dihydropyrimidine dehydrogenase (DPD) protein expression

The aim of this study was to detect the antitumor properties of Croatian propolis in BALB/c male and female mice injected with 4T1 mammary carcinoma. Furthermore, the gender-dependence of this effect and the possible involvement of combined effect of propolis and 5-Fluorouracil (5FU) on dihydropyrimidine dehydrogenase (DPD) transcriptional and translational level, were determined. In combination with 5FU propolis treatment induced gender-related effects. The results of the study revealed that pretreatment of mice with propolis combined with 5FU treatment prolonged the suppressive effect of 5FU on tumor growth and reduced the number of metastasis only in male mice. Only males pretreated with propolis prior to 5FU administration had decreased DPD protein level indicating higher sensitivity to 5FU. Thus, benefitial effects of propolis in male tumor-bearing mice treated with 5FU might be explained by increased sensitivity to 5FU as the result of translationally downregulated DPD.

Virological and immunological characteristics of fatal Epstein-Barr virus mononucleosis in a 17-year-old Caucasian male presenting with meningoencephalitis and hemophagocytic syndrome

In this report, the authors present a detailed immunological and virological assessment of an immunocompetent 17-year-old Caucasian male with a fatal Epstein-Barr virus (EBV) infectious mononucleosis presenting with meningoencephalitis and hemophagocytic syndrome. The patient with serologically confirmed EBV infectious mononucleosis was admitted to the hospital because of 3 weeks’ fever. Fine-needle aspiration of lymph nodes showed reactive hyperplasia with prominent hemophagocytosis. Percentages of intracellular interferon-gamma (IFN-γ) in CD4+ and CD8+ T cells in the peripheral blood progressively increased during the course of disease (10.2% and 8.5% on day 35; 30.1% and 53.2% on day 44; 42.2% and 75.2% on day 50; 36.1% and 50.6% on day 59, respectively). On day 50, the patient developed meningoencephalitis. Brain computed tomography (CT) was normal. Brain magnetic resonance imaging (MRI) showed multifocal inflammatory lesions in frontal and temporal cortex of the right hemisphere as well as severe perivascular inflammatory reaction. The patient was treated with steroids, cyclosporin A, and methotrexate intratecally. Following treatment, EBV viremia in the blood and cerebrospinal fluid (CSF) decreased from pretreatment values (54,490 copies of EBV DNA/ml and 39,500 copies/ml, respectively) to 8715 copies/ml in the blood and 14,690 in the CSF. Despite treatment, the patient remained unconscious and died of sepsis and pneumonia 3 months after initial symptoms. Immunohistochemical staining showed the presence of EBV in both perivascular infiltrates and grey matter. Enhanced Th1 response as shown by high levels of IFN-γ in peripheral blood lymphocytes may be a predictor of severe complications during acute EBV infection. Early implementation of immunosuppressive therapy in these patients should be considered.

Bilateral thalamic astrocytoma

We present a 68-year-old woman who presented with symptoms of frontotemporal dementia. Brain MRI revealed tumor mass in both thalami and according to WHO classification, the tumor corresponded to diffuse fibrillary astrocytoma grade II. This case points to the role of neuroimaging in patients presenting with classical symptoms of dementia.

Positron emission tomography-computed tomography and 4-hydroxynonenal-histidine immunohistochemistry reveal differential onset of lipid peroxidation in primary lung cancer and in pulmonary metastasis of remote malignancies

The Aim of the study was to reveal if PET-CT analysis of primary and of secondary lung cancer could be related to the onset of lipid peroxidation in cancer and in surrounding non-malignant lung tissue. Methods Nineteen patients with primary lung cancer and seventeen patients with pulmonary metastasis were involved in the study. Their lungs were analyzed by PET-CT scanning before radical surgical removal of the cancer. Specific immunohistochemistry for the major bioactive marker of lipid peroxidation, 4-hydroxynonenal (HNE), was done for the malignant and surrounding non-malignant lung tissue using genuine monoclonal antibody specific for the HNE-histidine adducts. Results Both the intensity of the PET-CT analysis and the HNE-immunohistochemistry were in correlation with the size of the tumors analyzed, while primary lung carcinomas were larger than the metastatic tumors. The intensity of the HNE-immunohistochemistry in the surrounding lung tissue was more pronounced in the metastatic than in the primary tumors, but it was negatively correlated with the cancer volume determined by PET-CT. The appearance of HNE was more pronounced in non-malignant surrounding tissue than in cancer or stromal cells, both in case of primary and metastatic tumors. Conclusions Both PET-CT and HNE-immunohistochemistry reflect the size of the malignant tissue. However, lipid peroxidation of non-malignant lung tissue in the vicinity of cancer is more pronounced in metastatic than in primary malignancies and might represent the mechanism of defense against cancer, as was recently revealed also in case of human liver cancer.

Pathology of acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an acute, monophasic neurologic syndrome that occurs after vaccination against various viruses and after many viral infections and rarely occurs again in the same patient. Weston Hurst disease or acute hemorrhagic encephalomyelitis (AHE) is a hyperacute ADEM variant that shares many pathological similarities with ADEM. ADEM clinically and neuropathologically faithfully reflects the animal model of experimental allergic encephalomyelitis (EAE), and animal studies have provided us with new insights into pathogenesis of this disorder. Although there is much controversy whether ADEM is a separate disease or just one of possible manifestations of multiple sclerosis, there are clear histopathological characteristics that support ADEM as a separate disease This mini review will focus on pathological characteristics of ADEM emphasizing differences from other types of idiopathic demyelinating diseases.