Expert opinion on the identification, risk assessment, and mitigation of microorganisms and parasites relevant to xenotransplantation products from pigs.

Xenotransplantation has the potential to address shortages of organs available for clinical transplantation, but concerns exist regarding potential risks posed by porcine microorganisms and parasites (MP) to the health of human recipients. In this study, a risk-based framework was developed, and expert opinion was elicited to evaluate porcine MP based on swine exposure and risk to human health. Experts identified 255 MP to include in the risk assessment. These were rated by experts for five criteria regarding potential swine exposure in the USA and human health risks. MP were subsequently categorized into three risk mitigation groups according to pre-defined rules: disqualifying porcine MP (due to their pathogenic potential, n = 130); non-disqualifying porcine MP (still relevant to consider for biosecurity or monitoring efforts, n = 40); and alert/watch list (not reported in the USA or MP not in swine, n = 85). Most disqualifying (n = 126) and non-disqualifying (n = 36) porcine MP can effectively be eliminated with high biosecurity programs. This approach supports surveillance and risk mitigation strategies for porcine MP in swine produced for xenotransplantation, such as documentation of freedom from porcine MP, or use of porcine MP screening, monitoring, or elimination options. To the authors' knowledge, this is the first effort to comprehensively identify all relevant porcine MP systematically and transparently evaluate the risk of infection of both donor animals and immunosuppressed human recipients, and the potential health impacts for immunosuppressed human recipients from infected xenotransplantation products from pigs.

Capromorelin: a ghrelin receptor agonist and novel therapy for stimulation of appetite in dogs.

Ghrelin is a hormone, secreted from cells in the stomach, which is important in the regulation of appetite and food intake in mammals. It exerts its action by binding to a specific G-protein-coupled receptor, the growth hormone secretagogue receptor 1a (GHS-R1a) which is found in areas of the brain associated with the regulation of food intake. Ghrelin causes a release of growth hormone (GH) through binding to GHS-R1a in the hypothalamus and pituitary gland. A class of compounds known as growth hormone secretagogues, or ghrelin receptor agonists, were developed for therapeutic use in humans for the stimulation of GH in the frail elderly, and have subsequently been studied for their effects on increasing appetite and food intake, increasing body weight, building lean muscle mass, and treating cachexia. Subsequent research has shown that ghrelin has anti-inflammatory and immunomodulatory effects. This article reviews the basic physiology of ghrelin and the ghrelin receptor agonists, including the available evidence of these effects in vitro and in vivo in rodent models, humans, dogs and cats. One of these compounds, capromorelin, has been FDA-approved for the stimulation of appetite in dogs (ENTYCE ®). The data available on the safety and effectiveness of capromorelin is reviewed, along with a discussion of the potential clinical applications for ghrelin receptor agonists in both human and veterinary medicine.

Capromorelin oral solution (ENTYCE®) increases food consumption and body weight when administered for 4 consecutive days to healthy adult Beagle dogs in a randomized, masked, placebo controlled study.

BACKGROUND: Dogs can suffer from inappetence caused by a variety of medical conditions. This may present as anorexia (complete loss of appetite), hyporexia (decreased appetite) or dysrexia (change in food preferences). A drug with a new mechanism of action, capromorelin, has potential to stimulate appetite in dogs. Capromorelin is a ghrelin receptor agonist, which mimics the action of endogenous ghrelin. It is a member of the growth hormone secretagogue (GHS) class of drugs. Capromorelin oral solution (ENTYCE®) was tested in healthy adult male and female Beagle dogs (n = 6 males and 6 females per group) for its effect on food consumption and body weight. A randomized, masked, placebo controlled study was conducted to measure the effects of a daily 3 mg/kg oral dose given over 4 days. Dogs were observed for clinical signs, physical examinations were completed prior to and at the end of treatment, and blood was drawn before and after treatment for evaluation of serum chemistry and hematology parameters. RESULTS: Capromorelin was well-tolerated, with no abnormalities seen on physical examination or clinical pathology. Some dogs showed increased salivation. Capromorelin treated dogs had increased mean (±SD) food consumption compared to placebo treated dogs (60.55 ± 39.87% versus -11.15 ± 14.23% respectively, P < 0.001). Treated dogs also had increased mean body weights compared to placebo treated dogs (5.96 ± 1.76% versus 0.053 ± 1.14% respectively, P < 0.001). CONCLUSIONS: This study supports the effectiveness of capromorelin oral solution as an appetite stimulant in dogs. Treatment with the oral solution resulted in dramatic increases in appetite, as measured by food consumption, of over 60% compared to placebo. The drug was well tolerated. Capromorelin is the first ghrelin receptor agonist developed for appetite stimulation in any species, and represents a novel mechanism of action for this clinical use.