Comparative efficacy and safety of mavacoxib and carprofen in the treatment of canine osteoarthritis.

A multi-site, masked, randomised parallel group study employing a double dummy treatment design was performed in canine veterinary patients to determine the comparative efficacy and safety of mavacoxib and carprofen in the treatment of pain and inflammation associated with osteoarthritis for a period of 134 days. Treatments were administered according to their respective summaries of product characteristics. Of 139 dogs screened, 124 were suitable for study participation: 62 of which were dosed with mavacoxib and 62 with carprofen. Both treatments resulted in a very similar pattern of considerable improvement as indicated in all parameters assessed by both owner and veterinarian. The primary efficacy endpoint 'overall improvement' was a composite score of owner assessments after approximately six weeks of treatment. Both drugs were remarkably effective, with 57/61 (93.4 per cent) of mavacoxib-treated dogs and 49/55 (89.1 per cent) of carprofen-treated dogs demonstrating overall improvement and with mavacoxib's efficacy being non-inferior to carprofen. The treatments had a similar safety profile as evidenced by documented adverse events and summaries of clinical pathology parameters. The positive clinical response to treatment along with the safety and dosing regimen of mavacoxib makes it an attractive therapy for canine osteoarthritis.

The anti-ghrelin Spiegelmer NOX-B11-3 blocks ghrelin- but not fasting-induced neuronal activation in the hypothalamic arcuate nucleus.

The hypothalamic arcuate nucleus (Arc) is the presumed target site for the orexigenic hormone ghrelin, which is secreted from the stomach during fasting. Ghrelin directly activates Arc neurones. Similar to exogenous ghrelin, overnight food deprivation also induces c-Fos expression in the Arc of mice. In the present study, we tested the role of endogenous ghrelin in the fasting-induced c-Fos expression in the Arc of mice. We used NOX-B11-3, the latest generation of the recently developed ghrelin-binding compounds, so-called RNA Spiegelmers (SPM) to block endogenous ghrelin action during food deprivation. The specificity and potency of this compound was also tested in electrophysiological and immunohistological experiments. In electrophysiological in vitro single cell recordings, NOX-B11-3 effectively blocked the excitatory effect of ghrelin in the medial Arc (ArcM) of rats whereas the biologically inactive control SPM had no effect. Furthermore, NOX-B11-3 (15 mg/kg i.p.) potently suppressed ghrelin-induced (25 microg/kg s.c., 12 h after SPM injection) c-Fos expression in the Arc. However, when injected at the beginning of a 14-h fasting period, the same dose of NOX-B11-3 had no effect on the c-Fos expression in the Arc of mice. These results demonstrate that NOX-B11-3 is a long-acting compound, which effectively blocks the effect of exogenous ghrelin on neuronal activity in the Arc under in vitro and in vivo conditions. Furthermore, increased ghrelin signalling does not appear to be a necessary factor for the activation of Arc neurones during food deprivation or other fasting-related signals might have masked or compensated for the loss of the ghrelin effect.

Effects of high carbohydrate and high fat diet on plasma metabolite levels and on i.v. glucose tolerance test in intact and neutered male cats.

To elucidate the impact of dietary influence on carbohydrate and lipid metabolism and on the development of diabetes mellitus in the carnivorous cat, a 3 weeks feeding trial was carried out on six sexually intact and six neutered adult male cats. The effects of two isonitrogenic diets, differing in carbohydrate and fat content, were investigated on plasma metabolite levels in a 24-h blood sampling trial. Plasma leptin concentrations were also determined at the beginning and at the end of the 24-h trial. Glucose and insulin response was measured in an i.v. glucose tolerance test. A 5 days long digestion trial was also performed, which revealed a high digestion capacity of both fat and carbohydrates in cats. The high fat diet induced a significant rise in the plasma triglyceride, FFA, beta-hydroxybutyrate and cholesterol concentration, while the elevation in the glucose level did not reach significance. In the glucose tolerance test no significant difference was found between the neutered and intact cats. However, independently of the sexual state, the cats on the high fat diet showed a slightly elongated glucose clearance and reduced acute insulin response to glucose administration. This is indicative of diminished pancreatic insulin secretion and/or beta-cell responsiveness to glucose. The results of this preliminary study may be the impetus for a long-term study to find out whether it is rather the fat rich ration than carbohydrate rich diet that is expected to impair glucose tolerance and thus might contribute to the development of diabetes mellitus in cats. Whether the alteration in glucose metabolism is due to altered leptin levels remains to be determined.

The anorectic hormone amylin contributes to feeding-related changes of neuronal activity in key structures of the gut-brain axis.

Amylin is a peptide hormone that is cosecreted with insulin from the pancreas during and after food intake. Peripherally injected amylin potently inhibits feeding by acting on the area postrema (AP), a circumventricular organ lacking a functional blood-brain barrier. We recently demonstrated that AP neurons are excited by a near physiological concentration of amylin. However, the subsequent neuronal mechanisms and the relevance of endogenously released amylin for the regulation of food intake are poorly understood. Therefore, we investigated 1) amylin's contribution to feeding-induced c-Fos expression in the rat AP and its ascending projection sites, and 2) amylin's ability to reverse fasting-induced c-Fos expression in the lateral hypothalamic area (LHA). Similar to amylin (20 microg/kg sc), refeeding of 24-h food-deprived rats induced c-Fos expression in the AP, the nucleus of the solitary tract, the lateral parabrachial nucleus, and the central nucleus of the amygdala. In AP-lesioned rats, the amylin-induced c-Fos expression in each of these sites was blunted, indicating an AP-mediated activation of these structures. Pretreatment with the amylin antagonist AC-187 (1 mg/kg sc) inhibited feeding-induced c-Fos expression in the AP. Food deprivation activated LHA neurons, a response known to be associated with hunger. This effect was reversed within 2 h after refeeding and also in nonrefed animals that received amylin. In summary, our data provide the first evidence that feeding-induced amylin release activates AP neurons projecting to subsequent relay stations known to transmit meal-related signals to the forebrain. Activation of this pathway seems to coincide with an inhibition of LHA neurons.