Ex vivo gut-hepato-biliary organ perfusion model to characterize oral absorption, gut-wall metabolism, pre-systemic hepatic metabolism and biliary excretion; application to midazolam.

To date, characterization of the first-pass effect of orally administered drugs consisting of local intestinal absorption and metabolism, portal vein transport and hepatobiliary processes remains challenging. Aim of this study was to explore the applicability of a porcine ex-vivo perfusion model to study oral absorption, gut-hepatobiliary metabolism and biliary excretion of midazolam. Slaughterhouse procured porcine en bloc organs (n = 4), were perfused via the aorta and portal vein. After 120 min of perfusion, midazolam, atenolol, antipyrine and FD4 were dosed via the duodenum and samples were taken from the systemic- and portal vein perfusate, intestinal faecal effluent and bile to determine drug and metabolite concentrations. Stable arterial and portal vein flow was obtained and viability of the perfused organs was confirmed. After intraduodenal administration, midazolam was rapidly detected in the portal vein together with 1-OH midazolam (EG-pv of 0.16±0.1) resulting from gut wall metabolism through oxidation. In the intestinal faecal effluent, 1-OH midazolam and 1-OH midazolam glucuronide (EG-intestine 0.051±0.03) was observed resulting from local gut glucuronidation. Biliary elimination of midazolam (0.04±0.01 %) and its glucuronide (0.01±0.01 %) only minimally contributed to the enterohepatic circulation. More extensive hepatic metabolism (FH 0.35±0.07) over intestinal metabolism (FG 0.78±0.11) was shown, resulting in oral bioavailability of 0.27±0.05. Ex vivo perfusion demonstrated to be a novel approach to characterize pre-systemic extraction of midazolam by measuring intestinal as well as hepatic extraction. The model can generate valuable insights into the absorption and metabolism of new drugs.

Evaluation of Normothermic Machine Perfusion of Porcine Livers as a Novel Preclinical Model to Predict Biliary Clearance and Transporter-Mediated Drug-Drug Interactions Using Statins.

There is a lack of translational preclinical models that can predict hepatic handling of drugs. In this study, we aimed to evaluate the applicability of normothermic machine perfusion (NMP) of porcine livers as a novel ex vivo model to predict hepatic clearance, biliary excretion, and plasma exposure of drugs. For this evaluation, we dosed atorvastatin, pitavastatin, and rosuvastatin as model drugs to porcine livers and studied the effect of common drug-drug interactions (DDIs) on these processes. After 120 minutes of perfusion, 0.104 mg atorvastatin (n = 3), 0.140 mg pitavastatin (n = 5), or 1.4 mg rosuvastatin (n = 4) was administered to the portal vein, which was followed 120 minutes later by a second bolus of the statin coadministered with OATP perpetrator drug rifampicin (67.7 mg). After the first dose, all statins were rapidly cleared from the circulation (hepatic extraction ratio > 0.7) and excreted into the bile. Presence of human-specific atorvastatin metabolites confirmed the metabolic capacity of porcine livers. The predicted biliary clearance of rosuvastatin was found to be closer to the observed biliary clearance. A rank order of the DDI between the various systems upon coadministration with rifampicin could be observed: atorvastatin (AUC ratio 7.2) > rosuvastatin (AUC ratio 3.1) > pitavastatin (AUC ratio 2.6), which is in good agreement with the clinical DDI data. The results from this study demonstrated the applicability of using NMP of porcine livers as a novel preclinical model to study OATP-mediated DDI and its effect on hepatic clearance, biliary excretion, and plasma profile of drugs. SIGNIFICANCE STATEMENT: This study evaluated the use of normothermic machine perfusion (NMP) of porcine livers as a novel preclinical model to study hepatic clearance, biliary excretion, plasma (metabolite) profile of statins, and OATP-mediated DDI. Results showed that NMP of porcine livers is a reliable model to study OATP-mediated DDI. Overall, the rank order of DDI severity indicated in these experiments is in good agreement with clinical data, indicating the potential importance of this new ex vivo model in early drug discovery.

Omega-3 fatty acids in boys with behavior, learning, and health problems.

The purpose of the study reported here was to compare behavior, learning, and health problems in boys ages 6 to 12 with lower plasma phospholipid total omega-3 or total omega-6 fatty acid levels with those boys with higher levels of these fatty acids. A greater frequency of symptoms indicative of essential fatty acid deficiency was reported by the parents of subjects with lower plasma omega-3 or omega-6 fatty acid concentrations than those with higher levels. A greater number of behavior problems, assessed by the Conners' Rating Scale, temper tantrums, and sleep problems were reported in subjects with lower total omega-3 fatty acid concentrations. Additionally, more learning and health problems were found in subjects with lower total omega-3 fatty acid concentrations. (Only more colds and more antibiotic use were reported by those subjects with lower total omega-6 fatty acids). These findings are discussed in relation to recent findings for omega-3 experimentally deprived animals.

Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder.

Attention-deficit hyperactivity disorder (ADHD) is the term used to describe children who are inattentive, impulsive, and hyperactive. The cause is unknown and is thought to be multifactorial. Based on the work of others, we hypothesized that some children with ADHD have altered fatty acid metabolism. The present study found that 53 subjects with ADHD had significantly lower concentrations of key fatty acids in the plasma polar lipids (20:4n-6, 20:5n-3, and 22:6n-3) and in red blood cell total lipids (20:4n-6 and 22:4n-6) than did the 43 control subjects. Also, a subgroup of 21 subjects with ADHD exhibiting many symptoms of essential fatty acid (EFA) deficiency had significantly lower plasma concentrations of 20:4n-6 and 22:6n-3 than did 32 subjects with ADHD with few EFA-deficiency symptoms. The data are discussed with respect to cause, but the precise reason for lower fatty acid concentrations in some children with ADHD is not clear.

Conflict resolution abilities of children with specific language impairment and children with normal language.

This study explored the conflict resolution ability of 30 children with specific language impairment (SLI) and 30 children with normal language (NL) in grades 3 through 7. The children participated in a hypothetical problem-solving activity in which an imaginary conflict was presented and a hypothetical solution was required. They also engaged in role enactments of conflicts. The children with SLI suggested fewer types of strategies to resolve hypothetical conflicts than their peers with NL. The groups did not differ in the number of strategy types used in the role-enactment contexts. The children with receptive and expressive SLI performed more poorly than the children with primarily expressive language deficits only on the role-enactment task. Similarities and differences in types of strategy used by the children with SLI and those with NL were found in both tasks. Explanations are offered for these findings.

Infant outcome following mid-trimester amniocentesis: development and physical status at age six months.

Ninety-one infants whose mothers had had amniocentesis, because age increased their risk for a fetal chromosome abnormality, were compared with 53 infants whose mothers chose not to have the test. Mental and motor development and temperament were studied to assess potential influence of amniocentesis on the brain. Physical growth was assessed and the infants were examined for orthopaedic abnormalities and needle injury. The results indicated that amniocentesis does not appear to influence infant mental and motor development, temperament, physical growth or the risk of orthopaedic abnormalities. However, amniocentesis is not entirely free of risk because several of the infants had needle marks. Reassessment of the cohort at age 4 and 7 years and will provide information on the potential longer term consequences of mid-trimester amniocentesis.

Midtrimester amniocentesis: obstetric outcome and neonatal neurobehavioral status.

The possible effects of midtrimester genetic amniocentesis on neurobehavioral status were studied in newborn infants of women who had had the procedure (N = 100) and in newborn infants of women who had declined the test (N = 56). Brazelton's Neonatal Behavioral Assessment Scale was administered to newborn infants born at term and did not reveal consequences of amniocentesis on neonatal orientation, range of state, motor ability, autonomic regulation, regulation of state, response decrement, or reflexes. Information on obstetric complications also was obtained. The findings raised questions regarding the temporal relationship between amniocentesis and fetal loss and focused attention on preterm birth as a potential risk that warrants further investigation. This study provides the foundation for our prospective longitudinal follow-up in which the cohort will be reassessed later in infancy and in childhood.