Increased transduction of human intestinal epithelial cells by adenoviral vectors in inflammatory bowel disease.

BACKGROUND: Delivery of genes encoding anti-inflammatory proteins has been proposed as a strategy for the treatment of inflammatory bowel disease (IBD). The goal of this study was to assess the ability of a standard adenoviral vector to transfect epithelial cells in intestinal explants from patients with IBD compared with controls. METHODS: Endoscopic colon biopsies obtained from patients with no history of IBD and endoscopically normal colon (n = 4), patients with a history of ulcerative colitis (UC; n = 5), and patients with a history of Crohn's disease (CD; n = 3) were placed in explant culture and exposed to an adenoviral vector carrying the nuclear targeted beta-galactosidase reporter gene. RESULTS: X-Gal staining showed that the total number of transduced cells per square millimeter was greater in UC explants than in controls (mean, 11.3 versus 0.9 blue nuclei/mm, respectively; P < 0.02) and that the frequency of epithelial cell transduction was greater in UC explants than in controls (86% versus 47% of explants, respectively; P = 0.01). Transduction of mature columnar surface epithelial cells occurred exclusively in UC and CD explants and was not seen in controls. Attenuated epithelial cells at sites of tissue damage or ulceration showed increased transduction compared with mature columnar epithelial cells (62% versus 19% of occurrences, respectively; P < 0.0001). CONCLUSIONS: We conclude that intestinal epithelial cells from IBD patients are more readily transfected by standard adenoviral vectors than are those from control patients. These results suggest that targeting genes to inflamed intestine through the luminal route may be possible.

Gene expression in the human intestine and correlation with oral valacyclovir pharmacokinetic parameters.

The transport of valacyclovir, the l-valyl ester of acyclovir, has been suggested to be mediated by several carrier-mediated pathways in cell culture and animal models. The role and importance of these transporters in modulating valacyclovir absorption in humans has not been determined, however. Recent advances in genomic technology have facilitated the rapid and simultaneous determination of global mRNA expression profiles for thousands of genes in tissue biopsies directly associated with the absorption process, thereby dramatically increasing the value of studies in humans. In this article, we describe correlations of pharmacokinetic parameters following oral valacyclovir or acyclovir administration with expression levels of intestinal genes in humans. Highly positive and significant correlations were observed with 4F2hc, an activator of cation-preferring amino acid transport systems, and human oligopeptide transporter (HPT1), an oligopeptide transporter expressed at higher levels in the human intestine compared with oligopeptide transporter (PEPT1). The validation of HPT1 microarray data with reverse transcription-polymerase chain reaction and the enhanced valacyclovir uptake in HeLa/HPT1 cells suggest that the role of HPT1 in transport of peptides and peptidomimetics drugs needs to be examined in more detail. The interrelation of 4F2hc and HPT1 in transport may be of interest. No significant correlations of valacyclovir pharmacokinetic parameters with PEPT1 and with organic cation or anion transporter expression levels were observed. The highly negative correlations observed with known efflux pumps such as MDR1 (P-glycoprotein) and MRP2 (cMOAT), as well as with the CYP450 IIIA subfamily may indicate that these proteins may regulate the cellular accumulation and metabolism of acyclovir.

Human jejunal permeability of cyclosporin A: influence of surfactants on P-glycoprotein efflux in Caco-2 cells.

PURPOSE: The purpose of this work was to determine the jejunal permeability of cyclosporin A (CsA) in humans and whether formulation variables modulate the effects of P-glycoprotein (P-gp) on the permeability of CsA in Caco-2 cells. METHODS: A solution containing CsA, phenylalanine, propranolol, polyethyleneglycol (PEG) 400, and PEG 4000 was perfused through a 10-cm jejunal segment in 12 subjects. Caco-2 transport studies were performed using previously reported methodology. RESULTS: The mean Peff (+/- SD) of CsA in humans was 1.65 (0.53). The mean permeabilities for phenylalanine, propranolol, and PEG 400 were 4.54 (2.39), 2.90 (1.28), and 0.83 (0.51) x 10(-4) cm/s, respectively. The presence of surfactants significantly decreased the permeabilities of CsA in both directions in Caco-2 cells. CONCLUSIONS: The results suggest that the effects of surfactants via micellar solubilization and inhibition of P-gp efflux on CsA transport in Caco-2 cells are significant. CsA can rightly be classified as a low solubility-high permeability Class II BCS drug and its highly variable absorption from Sandimmune oral formulations is the result of poor dissolution characteristics.

Intrasphincteric botulinum toxin versus pneumatic balloon dilation for treatment of primary achalasia.

GOALS: Despite a high success rate, pneumatic dilatation for achalasia is accompanied by a significant risk of esophageal perforation. Injection of botulinum toxin (botox) into the lower esophageal sphincter (LES) can lead to improvement in symptoms with reduced risk of complications. Direct comparisons of the two techniques are needed to define their role in clinical management. STUDY: We compared pneumatic dilatation to botox for patients with achalasia using a double blind, randomized study design. Patients underwent clinical, manometric, radiographic and endoscopic evaluation to confirm primary achalasia. They were randomized to receive either 80 units of botox into the LES or Witzel balloon dilatation. Patients also received sham dilatation or injection, respectively. The patients and investigators assessing symptom response were blinded to therapy. Symptoms and esophageal function were assessed at 3 weeks, 3 months and 1 year after therapy. Treatment failure was defined as the lack of decrease in symptom grade more than 1 or recurrence of symptoms. Patients with treatment failure crossed over to the alternative treatment. RESULTS: Thirty four patients were studied, and 31 completed the trial. Of the 18 patients randomized to Witzel dilatation, 16 (89%) of 18 remained in clinical remission. Of the two patients with treatment failure, one responded to botox injection. Of the 16 patients randomized to botox, (38%) 6 of 16 remained in clinical remission. Four patients had initial failure, and 6 relapsed at a mean of 4 months after therapy. Of the nine patients who crossed over to dilatation, seven responded well, but two required surgical management of perforation. Although both treatments had excellent initial clinical improvement, patients randomized to Witzel dilatation had superior long-term success ( < 0.01). CONCLUSION: Initial therapy with Witzel dilatation is associated with better long-term outcome than a single injection of botox. Because of the risk of endoscopic perforation, botox remains a viable alternative to dilatation.

Stooling and manometric findings after primary pull-throughs in Hirschsprung's disease: Perineal versus abdominal approaches.

BACKGROUND/PURPOSE: Primary pull-through via a perineal approach (PA) has recently been reported for Hirschsprung's disease. One criticism of this approach is that it requires a large amount of retraction on the anal sphincters. Additionally, because the procedure is new, most patients undergoing a PA are too young to assess long-term continence rates. This study examined early stooling patterns, anal sphincteric pressures, and number of enterocolitic episodes in infants who underwent a PA. Results were compared with a conventional combined transabdominal and perineal approach (TA). METHODS: Over 2 years, 26 pull-through procedures were performed. Nine of those were PA, and 17 were TA. Twelve of the 26 patients had formal manometric studies postoperatively. Results are expressed as mean +/- SD; unpaired t test and Chi;(2) were used for statistical analysis. RESULTS: Mean follow-up post-pull-through was 23 +/- 2.3 months for the TA and 14 +/- 1.9 months for the PA. Manometric resting sphincter pressure in the TA group averaged 79 +/- 17 mm Hg compared with 76 +/- 21 mm Hg in the PA group (P =.78). Number of stools per day was 3.3 +/- 0.6 in the TA group compared with 2.2 +/- 0.3 in the PA group (P =.17). Post-pull-through enterocolitis was experienced by 53% of the TA group (mean, 1.5 +/- 0.6 episodes) and 56% of the PA group (mean 0.9 +/- 0.4 episodes) for a P =.08 by Chi;(2) analysis. CONCLUSIONS: Manometric sphincter pressure and enterocolitic episodes after a PA for Hirschsprung's disease appear to be similar to results obtained with a conventional TA. Evaluation of early stooling frequency shows a comparable frequency after a PA. This suggests that both methods are safe, and the PA does not appear to compromise sphincter integrity.

Variability in cimetidine absorption and plasma double peaks following oral administration in the fasted state in humans: correlation with antral gastric motility.

The role of gastrointestinal motility and pH in determining cimetidine bioavailability as well as double peaks in plasma profiles following oral administration, in the quiescent or active phase of antral motility, to humans in the fasted state was examined. Plasma cimetidine-time curves did not show the presence of double peaks in any subject following intravenous administration. The incidence of double peaks was 73% following oral administration and was independent of antral migrating motility complex phase. Further, it was found that oral administration of cimetidine in the quiescent phase resulted in significantly higher bioavailability and in other pharmacokinetic parameters compared to that obtained following administration in the active phase. Excellent linearity in plots of motility peaks vs. plasma peaks with slopes close to unity were evident for both quiescent (r(2)=0.93) and active phase (r(2)=0.97) administration. A total of 14 peaks out of 22 (10 subjects, 64%) and 20 out of 27 peaks (11 subjects, 74%), were accounted for in quiescent and active phase oral administration, respectively. The proximal occurrence of plasma peaks to antral motility peaks typical of phase III contractions strongly implies that motility patterns may be responsible for secondary maxima following oral cimetidine administration in the fasted state.

Bile duct crystals do not contribute to sphincter of Oddi dysfunction.

BACKGROUND: Microlithiasis has been proposed as a cause of both occult gallbladder disease and of idiopathic pancreatitis. Theoretically, microlithiasis could also cause postcholecystectomy pain by causing temporary biliary obstruction and may be more common in patients with sphincter of Oddi dysfunction. The frequency of crystals in bile duct aspirates was assessed from patients with symptoms after cholecystectomy with and without elevated baseline sphincter of Oddi pressures. METHODS: A prospective analysis was performed on all patients with recurrent biliary pain after cholecystectomy who presented for ERCP and manometry between January 1998 and June 2000. All patients had aspirates obtained from the common bile duct for crystal analysis by using the aspirating port of the manometry catheter before the injection of contrast. Four to 20 mL of bile was examined by microscopy for both cholesterol and bilirubinate crystals. RESULTS: Sixty patients (83% women, mean age 44 years) were studied. Thirty-five had normal baseline biliary sphincter pressures and 25 elevated biliary baseline sphincter pressures (>40 mm Hg). Two patients in the normal pressure group and 1 in the elevated pressure group had cholesterol crystals present in their aspirate. No patient had bilirubinate crystals present. A 5% frequency of microlithiasis was identified overall. CONCLUSIONS: Bile duct crystals occur infrequently in patients with symptoms after cholecystectomy and are found in patients with normal and abnormal biliary sphincter manometry. This study suggests that the presence of bile duct crystals, or microlithiasis, does not play a role in sphincter of Oddi dysfunction.

Endoscopic management of biliary disease.

Therapeutic biliary endoscopy continues to evolve. Key articles this year primarily involve biliary stenting and biliary stone removal, the two important maneuvers available to the biliary endoscopist. The issues addressed in this review include follow-up after the use of multiple stents for benign strictures, unilateral versus bilateral stenting for Klatskin tumors, stent types and placement positions, the timing and approach to choledocholithiasis in the context of anticipated cholecystectomy, and resistant biliary duct stones.