Population differences in intestinal permeability to chromium EDTA

Population pharmacokinetics of intra-peritoneal gentamicin and the impact of varying dwell times on pharmacodynamic target attainment in patients with acute peritonitis undergoing peritoneal dialysis

While the use of intraperitoneal (i.p.) gentamicin is common in the treatment of peritoneal dialysis (PD)-related infections, the ability of these regimens to attain pharmacodynamic target indices of interest in blood and dialysate has not been widely reported. Pharmacokinetic (PK) data was obtained and analyzed from a multiple-dose PK study of i.p. gentamicin with 24 patients who received the drug at 0.6 mg/kg dose of body weight. The probability of target attainment (PTA) for indices of treatment success (i.p. peak/MIC ratio >10) and toxicity (plasma AUC < 120 mg*h/L) was determined for 0.3 to 1.2 mg/kg i.p. regimens every 24 h for dwell times of 2 to 6 hours and for the duration of 2-week course. In the peritoneum, successful PTA was achieved by all of the simulated regimens up to an MIC of 1 mg/L, and by doses equal to or greater than 0.6 mg/kg up to the MIC of 2 mg/L. At the susceptibility break point of 4 mg/L only the highest dose of 1.2 mg/kg is likely to provide adequate PTA. Probability of achieving exposure below the threshold of 120 mg*h/L in the daily AUC in plasma seems acceptable for all regimens at or below 0.6 mg/kg. Based on the model we developed, a gentamicin dose of 0.6 mg/kg is sufficient to treat organisms with an MIC of ≤2 mg/L without the risk of significant systemic exposure. The 1.2 mg/kg dose necessary to reach the pharmacodynamic target for efficacy at the clinical break point of 4 mg/L is likely to produce early toxic levels of exposure that is expected to be detrimental to the renal system.

Intestinal permeability to [51Cr]EDTA in infectious diarrhea

Orally administered [51Cr]EDTA was used to measure intestinal permeability in subjects with infectious diarrhea and in those without gastrointestinal complaints. [51Cr]EDTA was given to 87 subjects: 63 controls (32 normal controls, and 31 disease controls), and 24 patients with infectious diarrhea. Approximately 100 microCi of [51Cr]EDTA was given orally after an overnight fast. Urine was collected for the following 24 hr. Intestinal permeability to [51Cr]EDTA in both normal volunteers and in patients with a variety of diseases not associated with intestinal injury was low and results were in a relatively narrow range. Mean 24-hr urinary excretion of [51Cr]EDTA, calculated as a percent of the administered dose, in controls was 1.6% (0.2-3.5%). Patients with infectious diarrhea associated with invasive pathogens and/or intestinal inflammation had increased excretion of [51Cr]EDTA (mean 6.1%, P < 0.0001), with elevated excretions in 75%. These results demonstrate that intestinal infections must be considered as possible causes for increased intestinal permeability as assessed by the [51Cr]EDTA test.

Abnormal permeability precedes the development of a gluten sensitive enteropathy in Irish setter dogs

Intestinal permeability to 51Cr-EDTA was examined during the development of gluten sensitive enteropathy in dogs bred from affected Irish setters and reared on a normal wheat containing diet. Comparisons were made with litter mates reared on a gluten free diet and with a control group of age matched, clinically healthy Irish setters reared on the normal diet. Studies at 4, 6, 8, and 12 months of age were correlated with morphometric and biochemical examinations of peroral jejunal biopsy specimens. Permeability was increased at all ages in the group fed gluten free diet compared with control dogs, although there were no differences in villus height, intraepithelial lymphocyte density, and alkaline phosphatase activity. At four months, permeability in the normal diet group was greater than in controls, although comparable with that in the gluten free diet group. Permeability in the normal diet group increased further in conjunction with the development of partial villus atrophy and reduced alkaline phosphatase activity, and by 12 months permeability was significantly greater than in their gluten free diet litter mates and the control dogs. The findings suggest that an underlying permeability abnormality may be involved in the pathogenesis of gluten sensitive enteropathy in Irish setter dogs.