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The safety, tolerance, pharmacokinetic and pharmacodynamic effects of single doses of AT-1001 in coeliac disease subjects: a proof of concept study.
Paterson, BM, Lammers, KM, Arrieta, MC, Fasano, A, Meddings, JB
Alimentary pharmacology & therapeutics. 2007;26(5):757-66
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Plain language summary
In a healthy gut, intestinal epithelial cells, with their tight junctions, allow controlled passage of gluten and other fragments. When integrity of this system is compromised, as in celiac disease (CD), an inappropriate immune response to environmental antigens (i.e. gluten) develops. This is called hyper-intestinal permeability or 'leaky gut'. AT-1001 is a protein derived from a Gram-negative bacteria called Vibrio cholera. AT-1001 inhibits leaky gut and appears to have an impact on autoimmunity, making it a potential candidate for the treatment of CD. This double-blind, randomised placebo controlled study aims to determine the safety and tolerability of 12 mg doses of AT-1001 in CD subjects challenged with gluten. Intestinal permeability (IP) (measured urinary lactulose-to-mannitol) is used as a measure of drug efficacy. Male and female in-patients (n=20) aged 18-59y with diagnosed CD, on gluten-free diets for 6 months+ were, on days 1 and 3, treated with 12mg AT-1001 or placebo, followed by a sham gluten challenge, followed by the intestinal permeability measure. On day 2 the sham gluten was replaced by gluten. Puddings (containing sham or gluten) were served to all participants by kitchen staff in singe-blind fashion. For day 2 to day 1 IP change, there was a 70% increase in IP in the placebo group (P = 0.041) and no increase in the drug group, confirming the effects of gluten exposure on IP and the protective effects of AT-1001. Adverse events were mild (n=49) or moderate (n=3). Both groups experienced diarrhoea (an expected symptom in CD patients after exposure to gluten) but the AT-1001 treated volunteers reported less diarrhoea than placebo (P=0.017) suggesting a protective effect for AT-1001. This data demonstrate that 12 mg AT-1001 was generally safe, well tolerated and effectively mitigated gluten-induced GI adverse effects in coeliac patients when compared to placebo. Interferon (IFN)-γ (a marker of immune activity after acute dietary gluten) increased on day 3 in both the placebo group and AT-1001 group, but less so in the AT-1001 group though the difference was not statistically significant (likely due to small sample size). AT-1001 is well tolerated and appears to reduce intestinal barrier dysfunction, proinflammatory cytokine production, and gastrointestinal symptoms in coeliacs after gluten exposure. Larger studies are required to further elucidate the effects of AT-1001.
Abstract
BACKGROUND Lifelong adherence to a strict gluten-free diet is the cornerstone of coeliac disease treatment. Elucidation of disease pathogenesis has created opportunities for novel therapeutic approaches to coeliac disease. AT-1001 is an inhibitor of paracellular permeability whose structure is derived from a protein secreted by Vibrio cholerae. AIM: To determine the safety and tolerability of 12 mg doses of AT-1001 in coeliac disease subjects challenged with gluten. METHODS An in-patient, double-blind, randomized placebo-controlled safety study utilizing intestinal permeability, measured via fractional excretions of lactulose and mannitol, as an exploratory measure of drug efficacy. RESULTS Compared to placebo, no increase in adverse events occurred in patients exposed to AT-1001. Following acute gluten exposure, a 70% increase in intestinal permeability was detected in the placebo group, while none was seen in the AT-1001 group. Interferon-gamma levels increased in four of seven patients (57%) of the placebo group, but only in four of 14 patients (29%) of the AT-1001 group. Gastrointestinal symptoms were more frequently detected in the placebo group when compared to the AT-1001 group (P = 0.018). CONCLUSIONS AT-1001 is well tolerated and appears to reduce intestinal barrier dysfunction, proinflammatory cytokine production, and gastrointestinal symptoms in coeliacs after gluten exposure.
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The effect of pegylated human recombinant leptin (PEG-OB) on neuroendocrine adaptations to semi-starvation in overweight men.
Hukshorn, CJ, Menheere, PP, Westerterp-Plantenga, MS, Saris, WH
European journal of endocrinology. 2003;148(6):649-55
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Starvation results in a response in neuroendocrine system including suppression of some systems (such as thyroid and reproduction) and stimulation of others (such as the stress response). The mechanisms that cause these system responses remain unclear. Research has suggested that the hormone leptin (secreted by adipose tissue) may have a role in the physiological response to fasting. During periods of fasting, leptin levels can drop steeply and leptin given to starved rodents has shown an impact on the neuroendocrine system (such as the thyroid, adrenal and reproductive). This study explored whether raised leptin levels (administered in the form of long-acting pegylated recombinant leptin (PEG-OB)) had an impact on the neuroendocrine system responses to semi-starvation. In this randomised, double blind, placebo controlled trial, 24 overweight men (BMI 25-32) were prescribed a very low energy diet (500 kilocalorie) over 46 days to induce semi-starvation. Subjects either received 80mg of PEG-OB or a placebo. Hormones were measured (including those key to the thyroid, adrenal, somatotropic and sympathetic nervous system) using blood and urine samples. The results showed that men in the PEG-OB achieved significantly more weight loss (2.8kg). However, this did not reverse the fasting induced changes in key hormonal systems. The exception was luteinising hormone (LH) which was lower in the PEG-OB group compared to the placebo. The authors concluded that a lower level of leptin resulting from starvation may be a component of fasting induced changes in the reproductive system.
Abstract
OBJECTIVE Starvation induces a complex neuroendocrine response in humans thought to have evolved to defend against reduced energy intake. The drop in leptin levels observed during fasting has been implicated as a factor that triggers this adaptive response. To explore this hypothesis, we executed a randomized, double-blind, placebo-controlled study to investigate whether elevated leptin levels using long-acting pegylated human recombinant leptin (PEG-OB) influenced the neuroendocrine responses to semi-starvation in human subjects. DESIGN Twenty-four overweight male subjects (mean+/-s.e.m.; 34.8+/-1.3 yrs; 28.8+/-0.5 kg/m(2)) were prescribed a very low energy diet (2.1 MJ/day) to induce a state of semi-starvation for the next 46 days. In addition, all subjects received a weekly treatment of 80 mg PEG-OB or matching placebo. Hormone measurements were performed throughout the study period and included 5-h frequent hormone samplings and 24-h urine collections. RESULTS Weekly subcutaneous administration of PEG-OB led to significant additional weight loss (2.8 kg) but it did not reverse the fasting-induced changes in the thyroid, corticotropic, somatotropic axes and sympathetic nervous system activity. However, after adjustment for weight loss, the drop in mean luteinizing hormone levels was attenuated in the PEG-OB group compared with the placebo group. CONCLUSIONS These results suggest that a reduced level of leptin accompanying food restriction might be a component of the fasting-induced neuroendocrine inhibition of the human reproductive axis.
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Gastrointestinal permeability during exercise: effects of aspirin and energy-containing beverages.
Lambert, GP, Broussard, LJ, Mason, BL, Mauermann, WJ, Gisolfi, CV
Journal of applied physiology (Bethesda, Md. : 1985). 2001;90(6):2075-80
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Many athletes use aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) for analgesia. This study of 17 subjects aimed to assess whether the use of aspirin with prolonged exercise could increase gastrointestinal permeability. It also aimed to examine whether consumption of a carbohydrate-containing or a carbohydrate and glutamine-containing beverage could reduce this effect. Authors concluded that acute aspirin consumption before prolonged exercise could increase gastroduodenal and intestinal permeability. They also indicated that gastroduodenal permeability was significantly decreased by the ingestion of carbohydrate-containing beverages and that consumption of carbohydrate containing glutamine beverage provided no additional benefits than the carbohydrate alone beverage.
Abstract
The purpose of this study was to determine whether aspirin (A) ingestion combined with prolonged exercise increases gastrointestinal permeability and whether consumption of a carbohydrate-containing (CHO) or a CHO + glutamine-containing (CHO+G) beverage would reduce this effect. Seventeen subjects completed six experiments. They ingested A (1,300 mg) or placebo (P) pills the evening before and before running 60 min at 70% maximal oxygen uptake. Also, before running they ingested a solution containing 5 g lactulose (L), 5 g sucrose (S), and 2 g rhamnose (R). During each trial, either a 6% CHO beverage, a 6% CHO+G (0.6%; 41 mM) beverage, or a water placebo (WP) was consumed. For 4 h after a run, all urine was collected to measure urinary excretion of L, R, and S. S excretion (percentage of dose ingested; measure of gastroduodenal permeability) was significantly greater (P < 0.05) during the A trial while the subjects drank the WP compared with all other trials. Administration of A also significantly increased L/R (measure of intestinal permeability) for the CHO and WP trials compared with all P trials. Ingestion the CHO or CHO+G beverages significantly reduced S excretion and L excretion when A was administered, but it did not reduce L/R. These results indicate that gastroduodenal and intestinal permeability increase after A ingestion during prolonged running and that ingestion of a CHO beverage attenuates the gastroduodenal effect but not the intestinal effect. Furthermore, addition of G to the CHO beverage provided no additional benefit in reducing gastroduodenal or intestinal permeability.