Andrea Stofkova

Anxiety-like behavior in the elevated-plus maze tests and enhanced IL-1β, IL-6, NADPH oxidase-1, and iNOS mRNAs in the hippocampus during early stage of adjuvant arthritis in rats

We studied anxiety-like behavior in the elevated plus-maze (EPM) tests in male Lewis rats on days 2 and 4 of adjuvant arthritis (AA). In plasma we analyzed C-reactive protein (CRP), albumin, ACTH, corticosterone, in the hippocampus the mRNA expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), corticotrophin releasing factor (CRH), NADPH oxidases NOX1 and NOX2, and inducible NO-synthase (iNOS). EPM tests showed a higher anxiety index in AA rats on days 2 and 4 and reduction of total entries. On days 2 and 4 we found reduced plasma albumin, enhanced CRP, ACTH and corticosterone, and in the hippocampus enhanced mRNA for NOX1 and IL-1β in AA rats, on day 4 we found enhanced mRNAs for iNOS and IL-6, and reduced mRNA for CRH. The mRNA for NOX2 did not change on any experimental day. These results suggest enhanced anxiety, as well as locomotor impairment during the early phase of AA that correlate with enhanced mRNA expressions of parameters of oxidative stress NOX1, iNOS, and inflammatory cytokines IL-1β and IL-6 in the hippocampus.

Enhanced expressions of mRNA for neuropeptide Y and interleukin 1 beta in hypothalamic arcuate nuclei during adjuvant arthritis-induced anorexia in Lewis rats.

Objective: Food intake is activated by hypothalamic orexigenic neuropeptide Y (NPY), which is mainly under the dual control of leptin and ghrelin. Rat adjuvant arthritis (AA), similarly as human rheumatoid arthritis, is associated with cachexia caused by yet unknown mechanisms. The aim of our study was to evaluate NPY expression in hypothalamic arcuate nuclei (nARC) under the conditions of AA-induced changes in leptin, ghrelin and adiponectin. Since IL-1β is involved in the central induction of anorexia, we studied its expression in the nARC as well. Methods: AA was induced to Lewis rats using complete Freund’s adjuvant. On days 12, 15 and 18 after complete Freund’s adjuvant injection, the levels of leptin, adiponectin, ghrelin and IL-1β were determined by RIA or ELISA. The mRNA expressions for NPY, leptin receptor (OB-R), ghrelin receptor (Ghsr) and IL-1β were determined by TaqMan RT-PCR from isolated nARC. Results: In AA rats, decreased appetite, body mass and epididymal fat stores positively correlated with reduced circulating and epididymal fat leptin and adiponectin. Ghrelin plasma levels were increased. In nARC, mRNA for OB-R, Ghsr and NPY were overexpressed in AA rats. AA rats showed overexpression of mRNA for IL-1β in nARC while circulating, and spleen IL-1β was unaltered. Conclusion: During AA, overexpression of orexigenic NPY mRNA in nARC along with enhanced plasma ghrelin and lowered leptin levels occur. Decreased food intake indicates a predominant effect of the anorexigenic pathway. Activated expression of IL-1β in nARC suggests its role in keeping AA-induced anorexia in progress. The reduction in adiponectin may also contribute to AA-induced anorexia.

Effect of Amphetamine on Adult Male and Female Rats Prenatally Exposed to Methamphetamine

The aim of the present study was to examine the cross-sensitization induced by prenatal methamphetamine (MA) exposure to adult amphetamine (AMP) treatment in male and female rats. Rat mothers received a daily injection of MA (5 mg/kg) or saline throughout the gestation period. Adult male and female offspring (prenatally MA- or saline-exposed) were administered with AMP (5 mg/kg) or saline (1 ml/kg) in adulthood. Behaviour in unknown environment was examined in open field test (Laboras), active drug-seeking behaviour in conditioned place preference test (CPP), spatial memory in the Morris water maze (MWM), and levels of corticosterone (CORT) were analyzed by enzyme immunoassay (EIA). Our data demonstrate that in Laboras test, AMP treatment in adulthood increased general locomotion (time and distance travelled) regardless of the prenatal exposure and sex, while AMP increased exploratory activity (rearing) only in prenatally MA-exposed animals. AMP induced sensitization only in male rats, but not in females when tested drug-seeking behaviour in the CPP test. In the spatial memory MWM test, AMP worsened the performance only in females, but not in males. On the other hand, males swam faster after chronic AMP treatment regardless of the prenatal drug exposure. EIA analysis of CORT levels demonstrated higher level in females in all measurement settings. In males, prenatal MA exposure and chronic adult AMP treatment decreased CORT levels. Thus, our data demonstrated that adult AMP treatment affects behaviour of adult rats, their spatial memory and stress response in sex-specific manner. The effect is also influenced by prenatal drug exposure.

Effect of Feeding Status on Adjuvant Arthritis Severity, Cachexia, and Insulin Sensitivity in Male Lewis Rats

We studied the effect of food restriction, overfeeding, and normofeeding on cachexia, inflammatory and metabolic parameters, and insulin sensitivity in chronic adjuvant arthritis (AA) in rats. Food restriction during AA increased circulating ghrelin, corticosterone, decreased leptin, and ameliorated arthrogram score and systemic inflammation compared to normofeeding. Overfeeding worsened arthrogram score and systemic inflammation, and led to lipid accumulation in the liver, but not to alterations of adipokine and ghrelin plasma levels relative to normofeeding. Independently of feeding status, AA induced cachexia, in which modulation of mRNA expressions for appetite-regulating neuropeptides (NPY, AgRP, POMC, CART) in the arcuate nucleus (ARC) does not play a primary role. The overexpression of IL-1β mRNA in the ARC suggests its role in the mechanisms of impaired energy balance during AA under all feeding conditions. Normal HOMA index in all arthritic groups does not indicate the development of insulin resistance by feeding interventions in these rats.

Triazole GHS-R1a antagonists JMV4208 and JMV3002 attenuate food intake, body weight, and adipose tissue mass in mice

The only peripherally released orexigenic hormone, ghrelin, plays a key role in food intake and body weight regulation. Antagonizing the ghrelin receptor, GHS-R1a, represents a promising approach for anti-obesity therapy. In our study, two novel GHS-R1a antagonists JMV4208 and JMV3002, which are trisubstituted 1,2,4-triazoles, decreased food intake in fasted lean mice in a dose-dependent manner, with ED50 values of 5.25 and 2.05 mg/kg, respectively. Both compounds were stable in mouse blood, with half-lives of 90 min (JMV4208) and 60 min (JMV3002), and disappeared from the blood 8h after administration. Fourteen days of treatment with the ghrelin antagonists (20 mg/kg twice a day) decreased food intake, body weight and adipose tissue mass in mice with diet-induced obesity (DIO). These results are likely attributable to an impact on food intake reduction and an attenuated expression of the lipogenesis-promoting enzymes (acetyl-CoA carboxylase 1 in subcutaneous fat and fatty acid synthase in subcutaneous and intraperitoneal fat). The decrease in fat mass negatively impacted circulating leptin levels. These data suggest that JMV4208 and JMV3002 could be useful therapeutic agents for the treatment of obesity.

Acknowledgement to the Reviewers

R. Ader, Rochester, N.Y., USA M. Anthracopoulos, Rio Patras, Greece E.G. Araujo, Rio de Janeiro, Brazil E. Arzt, Buenos Aires, Argentina A. Aubert, Tours, France L. Barbeito, Montevideo, Uruguay M. Bauer, Porto Alegre, Brazil I. Berczi, Winnipeg, Man., Canada H.O. Besedovsky, Marburg, Germany S. Bornstein, Dresden, Germany O. Bottasso, Santa Fe, Argentina S.D. Brain, London, UK A. Buske-Kirschbaum, Dresden, Germany M. Canal, Manchester, UK E. Charmandari, Athens, Greece D. Chiasserini, Perugia, Italy F.A. Costa-Pinto, São Paulo, Brazil M. Dardenne, Paris, France E.G. de Moura, Rio de Janeiro, Brazil K. Dornmair, Martinsried, Germany R.L. Doty, Philadelphia, Pa., USA J. Drouin, Montreal, Que., Canada G.E. Duffield, Notre Dame, Ind., USA A.J. Dunn, Honolulu, Hawaii, USA I. Elenkov, Rome, Italy G.G. Freund, Urbana, Ill., USA R. Furlan, Milan, Italy R.C. Gaillard, Lausanne, Switzerland Y. Gidron, Tilburg, The Netherlands N. Gilhus, Bergen, Norway F. Haour, Paris, France K. Hirata, Kyushu, Japan S.K. Jindal, Chandigarh, India J. Kasckow , Pittsburgh, Pa., USA T. Katafuchi, Fukuoka, Japan