Jadranka Varljen

Lithium plus pilocarpine induced status epilepticus--biochemical changes.

The aim of the study was to investigate the changes in biochemical mechanisms facilitating cellular damages in the lithium plus pilocarpine treatment and the resulting status epilepticus. The whole brain free fatty acid (FFA) level as well as the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutamate dehydrogenase, aspartate-aminotransferase (AST), alanine-aminotransferase, gamma-glutamoyl transferase, alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and creatine kinase in the frontal cortex, cerebellum, hippocampus and pons-medulla region of Hannover-Wistar rats were determined. The control group was intact with no previous experimental history. LiCl (125 mg/kg i.p.) was injected 20 h prior to pilocarpine (30 mg/kg i.p.) and the treated rats were sacrificed 1 or 2 1/2 h after pilocarpine administration. The results show that lithium plus pilocarpine administration and the resulting status epilepticus produced the significant increase of the brain FFA content. Decreased GPX activities were detected in the frontal cortex, cerebellum and hippocampus of the treated rats without the accompanying decrease of SOD activity. Increased AST and LDH activities were observed in the frontal cortex, increased soluble ALP activities in the frontal cortex and pons-medulla region whereas the increased activity of membrane bound ALP was detected in the hippocampus of the rats with status epilepticus. Activities of the other analysed enzymes did not change in the examined brain regions. The presented data indicate clear regional differences of biochemical changes caused by lithium plus pilocarpine treatment and the resulting status epilepticus, frontal cortex being the most affected site.

Pentylenetetrazol-induced seizures and kindling: changes in free fatty acids, superoxide dismutase, and glutathione peroxidase activity

The whole brain free fatty acid (FFA) level, as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were determined in the frontal cortex, cerebellum, hippocampus, and pons-medulla region of the single pentylenetetrazol (PZT)-treated and PZT-kindled Hannover-Wistar rats. PZT administration in the convulsive dose caused significant increase of the brain FFA content. Decreased SOD activity was detected in the frontal cortex of PZT-kindled rats, whereas decreased GPX activity was found in the frontal cortex and cerebellum of all treated rats, as well as in the hippocampus and pons-medulla of PZT-kindled rats. Kindling caused distinctive change of antioxidative defense in the frontal cortex, hippocampus, and pons-medulla region.

Altered activities of rat brain metabolic enzymes caused by pentylenetetrazol kindling and pentylenetetrazol-induced seizures

The aim of our study was to investigate amino acid and energy metabolism of pentylenetetrazol (PTZ)-kindled animals. Glutamate dehydrogenase, aspartate-aminotransferase (AST), alanine-aminotransferase, gamma-glutamyltransferase, alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and creatine kinase (CK) were determined in the frontal cortex, cerebellum, hippocampus and pons-medulla regions of Hannover-Wistar rats. The rats were randomly divided into four experimental groups: (a) control; (b) rats which received a single PTZ injection in a subconvulsive dose of 40 mg/kg i.p.; (c) rats which received a single PTZ injection in a convulsive dose of 50 mg/kg i.p.; and (d) PTZ-kindled rats. Kindling increased ALP activity throughout the brain, elevated AST as well as LDH activity in the frontal cortex and hippocampus and decreased CK activity in the frontal cortex and cerebellum. Acute seizures of the same intensity did not induce these alterations. The observed effects therefore are obviously linked to the kindling phenomenon and not to seizure activity. Changes appeared mainly in the frontal cortex and hippocampus, i.e. brain areas believed to be directly involved in kindling.

Altered Activities of Rat Brain Metabolic Enzymes in Electroconvulsive Shock-Induced Seizures

Summary:  Purpose: Electroconvulsive shock (ECS) induces generalized seizure activity and provides an excellent experimental model for studying the effects of global electrical stimulation on various biochemical parameters. The aim of this work was to investigate the influence of a single or repeated ECS‐induced seizures on rat brain metabolism.

Electroconvulsive shock in rats: changes in superoxide dismutase and glutathione peroxidase activity.

Seizures trigger a variety of biochemical processes including an influx of extracellular Ca(2+), activation of membrane phospholipases, liberation of free fatty acids, diacylglycerols, eicosanoids, lipid peroxides and free radicals. These lipid metabolites along with abnormal ion homeostasis may be involved in cell injury and cell death. The aim of this study was to determine brain antioxidant enzyme activities in rats with electroconvulsive shock (ECS)-induced seizures. ECS, single or repeated, induced a decrease in superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities in various brain regions. The most prominent changes of enzymatic activities were observed in rats that received five ECSs with 24-h recovery period between them. Decreased SOD activity was observed in the frontal cortex of all treated animals except those sacrificed 24 h after single ECS, in the cerebellum of the animals that received repeated ECSs, in the hippocampus of animals that were decapitated 2 h after a single ECS and in the pons-medulla region of rats that received five daily ECSs. Decreased GPX activity was found in all examined brain regions of the rats that received five ECSs, the cortex and hippocampus of rats that were decapitated 2 h after single ECS and the cortex of those that received 10 ECSs with 48 h between them. The results show that neither 24-h nor 48-h recovery period was sufficient for the normalisation of antioxidative enzyme activities after repeated ECS treatment.

Neuroimmunomodulative properties of dipeptidyl peptidase IV/CD26 in a TNBS‐induced model of colitis in mice

Causal connections between dipeptidyl peptidase IV, also known as CD26 molecule (DPP IV/CD26) and inflammatory bowel disease (IBD) have been shown, but mechanisms of these interactions are unclear. Our hypothesis was that DPP IV/CD26 could affect the neuroimmune response during inflammatory events. Therefore, we aimed to evaluate its possible role and the relevance of the gut–brain axis in a model of IBD in mice. Trinitrobenzenesulfonic acid‐induced (TNBS) colitis was induced in CD26‐deficient (CD26−/−) and wild‐type (C57BL/6) mice. Pathohistological and histomorphometrical measurements were done. Concentrations and protein expressions of DPP IV/CD26 substrates neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) were determined. Concentrations of IL‐6 and IL‐10 were evaluated. Investigations were conducted at systemic and local levels. Acute inflammation induced increased serum NPY concentrations in both mice strains, more enhanced in CD26−/− mice. Increased NPY concentrations were found in colon and brain of C57BL/6 mice, while in CD26−/− animals only in colon. VIP and IL‐6 serum and tissue concentrations were increased in both mice strains in acute inflammation, more pronouncedly in CD26−/− mice. IL‐10 concentrations, after a decrease in serum of both mice strains, increased promptly in CD26−/− mice. Decreased IL‐10 concentration was found in brain of C57BL/6 mice, while it was increased in colon of CD26−/− mice in acute inflammation. DPP IV/CD26 deficiency affects the neuroimmune response at systemic and local levels during colitis development and resolution in mice. Inflammatory changes in the colon reflected on investigated parameters in the brain, suggesting an important role of the gut–brain axis in IBD pathogenesis. J. Cell. Biochem. 112: 3322–3333, 2011.

The influence of nicardipine and ifenprodil on the brain free arachidonic acid level and behavior in hypoxia-exposed rats

1. The effects of the calcium channel blockers, nicardipine and ifenprodil, on the brain free arachidonic acid level and learning ability in rats exposed to hypoxia were examined. 2. Adult rats were injected with 0.003; 0.01; 0.03; 0.1; 0.3 or 1.0 mg/kg of tested drugs i.p. Thirty min later the learning ability was tested in a passive avoidance task according to the step-through procedure. Immediately after the training trial, the animals were subjected to a period of oxygen deprivation hypoxia until the loss of the righting reflex. The retention trial was carried out 24 hr later. 3. The other groups of animals were pretreated with mentioned substances before hypoxia-exposure. Fifteen min after the loss of the righting reflex they were decapitated and brains were frozen in liquid nitrogen. The brain free arachidonic acid level was quantified by gas chromatography. 4. Both nicardipine and ifenprodil were effective in preventing a memory decline in hypoxia-exposed rats but did not prevent the accumulation of the brain free arachidonic acid in hypoxia-exposed rats. 5. The protective effects of both substances in behavioral studies during acute brain damage caused by hypoxia could not be explained by the prevention of the increase of the brain free arachidonic acid, but by some other mechanism.

Serum and intestinal dipeptidyl peptidase IV (DPP IV/CD26) activity in children with celiac disease.

Objective: Dipeptidyl peptidase IV (DPP IV/CD26) is involved in the degradation of proline-rich proteins such as gliadin and in modulation of the immune response. The aim of this study was to examine the possible causal connection between DPP IV enzyme activities and celiac disease (CD) in children. Patients and Methods: Intestinal mucosal biopsy specimens were obtained from 97 patients. The patients were divided into 3 groups: patients with active CD (n = 38), patients with malabsorption syndrome (MS) of other causes (n = 37), and control patients (n = 22). In addition, blood samples were collected from 48 patients with active CD and 50 control patients without gastrointestinal diseases. DPP IV enzyme activity was measured in the intestinal mucosal biopsy specimens and in the serum samples. Results: DPP IV activity in the small intestine correlated inversely with the grade of mucosal damage in the CD (r = −0.92, P < 0.001) and MS groups (r = −0.90, P < 0.001). Intestinal DPP IV activity was statistically significantly lower in the CD and MS groups than in the control group (P < 0.001). By contrast, serum DPP IV activity was not significantly different between the CD and control groups. Conclusions: Our results suggest that the decrease in intestinal DPP IV activity is not specific to CD because it correlates with the level of mucosal damage in both patients with CD and those with MS. In addition, it seems that serum DPP IV activity cannot be used as a specific noninvasive diagnostic or prognostic marker of CD.

THE INFLUENCE OF AGE ON INTESTINAL DIPEPTIDYL PEPTIDASE IV (DPP IV/CD26), DISACCHARIDASES, AND ALKALINE PHOSPHATASE ENZYME ACTIVITY IN C57BL/6 MICE

The objective of this study was to determine and describe the age-related changes in intestinal brush border membrane enzyme activities that occur in C57Bl/6 mice. Specifically, jejunal, duodenal, and ileal dipeptidyl peptidase IV/CD26, disaccharidase (lactase, sucrase, and maltase), and alkaline phosphatase activities were determined. A significant correlation between analyzed intestinal brush border membrane enzyme activities and animal age was found. Our study revealed that intestinal dipeptidyl peptidase IV/CD26, lactase, sucrase, maltase, and alkaline phosphatase activities decline significantly with age (p < .05). Nevertheless, the horizontal (duodenum to ileum) enzyme activity patterns are not affected by age.

Decreased soluble dipeptidyl peptidase IV activity as a potential serum biomarker for COPD.

OBJECTIVES The objective of this study was to measure soluble dipeptidyl peptidase IV (sDPPIV) activity in sera of patients with stable chronic obstructive pulmonary disease (COPD) in comparison to healthy controls. The main goal was to assess changes in the enzyme activity in relation to severity of the disease, age and smoking history and to evaluate diagnostic accuracy for prediction of COPD by level of serum sDPPIV activity. DESIGN AND METHODS The study included 106 patients with stable COPD (GOLD II-GOLD IV stages) and 38 healthy controls. Serum sDPPIV activity as well as some inflammatory markers (CRP, total and differential leukocyte counts) was measured. Multivariate logistic regression models were applied to analyze association of sDPPIV activity and inflammatory markers in risk estimation for COPD development. RESULTS sDPPIV activity in COPD patients was significantly reduced when compared to healthy controls. Decrease was observed already in GOLD II stage. Age and smoking history did not influence sDPPIV activity. Very good diagnostic accuracy (AUC=0.833; sensitivity and specificity of 85.7% and 78.9%, respectively) for GOLD II and good diagnostic accuracy (AUC=0.801; sensitivity and specificity of 65.1% and 86.8%, respectively) for total cohort of COPD patients were found. The multivariate logistic regression model showed that the use of sDPPIV in combination with CRP and lymphocyte proportion improved diagnostic strength and gave an AUC of 0.933. CONCLUSIONS sDPPIV activity is decreased in COPD patients as early as in GOLD II stage. Very good diagnostic accuracy of sDPPIV activity suggests it as a candidate biomarker for early diagnosis of COPD.