Nathalie Huyghebaert

Biological containment of genetically modified Lactococcus lactis for intestinal delivery of human interleukin 10

Genetically modified Lactococcus lactis secreting interleukin 10 provides a therapeutic approach for inflammatory bowel disease. However, the release of such genetically modified organisms through clinical use raises safety concerns. In an effort to address this problem, we replaced the thymidylate synthase gene thyA of L. lactis with a synthetic human IL10 gene. This thyA− hIL10+ L. lactis strain produced human IL-10 (hIL-10), and when deprived of thymidine or thymine, its viability dropped by several orders of magnitude, essentially preventing its accumulation in the environment. The biological containment system and the bacteriums capacity to secrete hIL-10 were validated in vivo in pigs. Our approach is a promising one for transgene containment because, in the unlikely event that the engineered L. lactis strain acquired an intact thyA gene from a donor such as L. lactis subsp. cremoris, the transgene would be eliminated from the genome.

Adenosine 5′-triphosphate (ATP) supplements are not orally bioavailable: a randomized, placebo-controlled cross-over trial in healthy humans

BackgroundNutritional supplements designed to increase adenosine 5′-triphosphate (ATP) concentrations are commonly used by athletes as ergogenic aids. ATP is the primary source of energy for the cells, and supplementation may enhance the ability to maintain high ATP turnover during high-intensity exercise. Oral ATP supplements have beneficial effects in some but not all studies examining physical performance. One of the remaining questions is whether orally administered ATP is bioavailable. We investigated whether acute supplementation with oral ATP administered as enteric-coated pellets led to increased concentrations of ATP or its metabolites in the circulation.MethodsEight healthy volunteers participated in a cross-over study. Participants were given in random order single doses of 5000 mg ATP or placebo. To prevent degradation of ATP in the acidic environment of the stomach, the supplement was administered via two types of pH-sensitive, enteric-coated pellets (targeted at release in the proximal or distal small intestine), or via a naso-duodenal tube. Blood ATP and metabolite concentrations were monitored by HPLC for 4.5 h (naso-duodenal tube) or 7 h (pellets) post-administration. Areas under the concentration vs. time curve were calculated and compared by paired-samples t-tests.ResultsATP concentrations in blood did not increase after ATP supplementation via enteric-coated pellets or naso-duodenal tube. In contrast, concentrations of the final catabolic product of ATP, uric acid, were significantly increased compared to placebo by ~50% after administration via proximal-release pellets (P = 0.003) and naso-duodenal tube (P = 0.001), but not after administration via distal-release pellets.ConclusionsA single dose of orally administered ATP is not bioavailable, and this may explain why several studies did not find ergogenic effects of oral ATP supplementation. On the other hand, increases in uric acid after release of ATP in the proximal part of the small intestine suggest that ATP or one of its metabolites is absorbed and metabolized. Uric acid itself may have ergogenic effects, but this needs further study. Also, more studies are needed to determine whether chronic administration of ATP will enhance its oral bioavailability.

Taste-masked quinine sulphate pellets: bio-availability in adults and steady-state plasma concentrations in children with uncomplicated Plasmodium falciparum malaria.

Abstract Background: Quinine sulphate (QS), like most other antimalarials, is in tablet form designed for adults. In children, treatment is based on breaking the tablets to adapt the dose to the childs bodyweight. However, poor breakability owing to the tablet design or the absence of a score line can lead to inaccurate dosage. Furthermore, QS is very bitter which reduces its acceptability to children. QS taste-masked pellets have been developed which offer more flexibility in adapting dosage to a childs weight. Aims: To evaluate the oral bio-availability of QS taste-masked pellets in healthy adult volunteers and to determine steady-state plasma concentrations in children aged <5 years with uncomplicated Plasmodium falciparum malaria. Methods: Healthy adult volunteers at Kigali University Hospital received a single dose of 600 mg QS as tastemasked pellets or as commercially available tablets. A total of 56 children <5 years with uncomplicated P. falciparum malaria were recruited among patients attending Butare University Hospital and nearby health centres and treated with QS taste-masked pellets, 10–12.5 mg/kg every 8 h for 7 days. Quinine steady-state plasma concentrations were assessed on the 4th day of treatment. Results: Following administration of taste-masked pellets to healthy adult volunteers, peak plasma concentration (Cmax) and area-under-the-curve (AUC) (Cmax 4.7 μg.ml−1, AUC0–24 63.5 μg.h.ml−1) were significantly higher (p<0.05) than for tablets (Cmax 3.7 μg.ml−1, AUC0–24 52.4 μg.h.ml−1), but still within the limits reported for quinine. The steady-state concentrations in children were in the therapeutic range for quinine. All the children recovered and completed the 14-day follow-up. Conclusion: QS taste-masked pellets offered the possibility to easily adjust the dose to the bodyweight of the child and can be used as an alternative to dividing tablets.

Compounding of vitamin A, D3, E and K3 supplements for cystic fibrosis patients: formulation and stability study

Background and objective:  Cystic fibrosis (CF) patients suffer from malabsorption of fat‐soluble vitamins (A, D, E and K). These vitamins are available as water‐dispersible (A, D3 and E) or water‐soluble grades (K3), which is favoured in CF patients as they fail to absorb oil‐based products. The objective of this study was to determine stability of these raw materials after opening the original package and to develop a compounded formulation of acceptable quality, stability and taste, allowing flexible dose adaptation and being appropriate for administration to children and elderly people.