Effects of minimizing access trauma in laparoscopic colectomy in patients with IBD.

BACKGROUND: Laparoscopic interventions to minimize access trauma are increasingly gaining importance for both cosmetic reasons and lower postoperative morbidity. The aim of this study was to compare the clinical outcomes for different laparoscopic colectomy and proctocolectomy accesses considering IBD. A comparison was made between total laparoscopic (LR)-without an extra incision for sample--and laparoscopic-assisted resection using a small incision for retrieval of the specimen (LAR) PATIENTS AND METHODS: From 2006 to 2012, 109 IBD patients underwent minimal invasive total colectomy or proctocolectomy. Patients were subdivided according to access into LR and LAR. Perioperative outcomes were evaluated. RESULTS: 86 patients with Ulcerative Colitis (UC) and 23 with Crohn's disease (CD) were included (LR: 64 UC/13 CD, LAR: 22 UC/10 CD). Among them, there were no differences in age, BMI, sex, ASA score or pre-existing immunosuppression. Patients with LR and UC had a higher disease activity score (Truelove III LR: 42 %, LAR: 5 %; p = 0.005). The Crohn's Disease Activity Index did not differ. Patients with LR had a shorter operating time (LR: 211.5, LAR: 240 min; p = 0.002). There was no significant difference in hospital stay (LR: 11, LAR: 12.5 days; p ≥ 0.05), length of stay at the ICU (both 1 days; p ≥ 0.05), duration of required analgesia (LR: 7 days, LAR: 8 days; p ≥ 0.05), and nutritional build-up (both 5 days; p ≥ 0.05). Groups had the same overall complication rate, but surgical site infection rates tended to be higher in patients with LAR (LR: 9.1 %, LAR: 21.9 %, p = 0.07). DISCUSSION: Laparoscopic procedures for colectomy and proctocolectomy are safe and effective techniques for patients with colon involvement and IBD. Minimizing the access trauma in laparoscopic colectomy offers a potential advantage of reduced surgical site infections, especially for frequently immunosuppressed IBD patients.

Repeatability of anorectal manometry in healthy volunteers and patients.

BACKGROUND: Anorectal manometry is used extensively in the assessment of patients with disorders of the pelvic floor. The present study investigated the repeatability of anorectal manometry in healthy volunteers and patients. PATIENTS AND METHODS: A total of 30 healthy volunteers (15 men and 15 women) and 10 patients with fecal incontinence (4 men and 6 women) underwent perfusion manometry and volumetry. Intraindividual variability was evaluated using the intraindividual correlation coefficient (ICC). Interindividual variability was expressed as the standard deviation from the calculated mean values. RESULTS: We found a high intraindividual correlation for the squeezing pressure (ICC 0.75-0.95), vector volume (ICC 0.88-0.97), and rectal perception (ICC 0.82-0.98). The anal resting pressure showed moderate repeatability (ICC 0.60-0.72). However, with regard to sphincter asymmetry, rectal compliance, and the rectoanal inhibitory reflex, a wide range of variability was found. In the female volunteers, the squeezing pressure and vector volume were lower than in those in the male volunteers. The anal pressure, vector volume, thresholds for urgency, and the maximum tolerable volume were lower in the incontinent patients than in the healthy volunteers. CONCLUSIONS: The squeezing pressure, vector volume, and rectal perception allow a reliable analysis of anal sphincter function. Sphincter asymmetry, rectal compliance, and the rectoanal inhibitory reflex were of limited diagnostic value.

Complications after end-to-end vs. side-to-side anastomosis in ileocecal Crohn's disease--early postoperative results from a randomized controlled multi-center trial (ISRCTN-45665492).

BACKGROUND: Recurrent Crohn's disease activity at the site of anastomosis after ileocecal resection is of great surgical importance. This prospective randomized multi-center trial with an estimated case number of 224 patients was initially planned to investigate whether stapled side-to-side anastomosis, compared to hand-sewn end-to-end anastomosis, results in a decreased recurrence of Crohn's disease following ileocolic resection (primary endpoint). The secondary endpoint was to focus on the early postoperative results comparing both surgical methods. The study was terminated early due to insufficient patient recruitment and because another large study investigated the same question, while our trial was ongoing. METHODS AND STUDY DESIGN: Patients with stenosing ileitis terminalis in Crohn's disease who underwent an ileocolic resection were randomized to side-to-side or end-to-end anastomosis. Due to its early discontinuation, our study only investigated the secondary endpoints, the early postoperative results (complications: bleeding, wound infection, anastomotic leakage, first postoperative stool, duration of hospital stay). RESULTS: From February 2006 until June 2010, 67 patients were enrolled in nine participating centers. The two treatment groups were comparable to their demographic and pre-operative data. BMI and Crohn's Disease Activity Index were 22.2 (± 4.47) and 200.5 (± 73.66), respectively, in the side-to-side group compared with 23.3 (± 4.99) and 219.6 (± 89.03) in the end-to-end group. The duration of surgery was 126.7 (± 42.8) min in the side-to-side anastomosis group and 137.4 (± 51.9) min in the end-to-end anastomosis group. Two patients in the end-to-end anastomosis group developed an anastomotic leakage (6.5%). Impaired wound healing was found in 13.9% of the side-to-side anastomosis group, while 6.5% of the end-to-end anastomosis group developed this complication. The duration of hospital stay was comparable in both groups with 9.9 (± 3.93) and 10.4 (± 3.26) days, respectively. CONCLUSIONS: Because of the early discontinuation of the study, it is not possible to provide a statement about the perianastomotic recurrence rates regarding the primary endpoint. With regard to the early postoperative outcome, we observed no difference between the two types of anastomosis.

Recombinant human beta 2-defensin fusion proteins as a tool to investigate defensin structure and function in small human intestinal tissue samples.

OBJECTIVE: Effects of immune cells on the beta 2 (ß2)-defensin (HBD2) expression and its antibacterial activity in the intestinal mucosa of patients with inflammatory bowel diseases remains unclear. The small size of these proteins presents a major challenge in localizing antibacterial activities in human intestinal tissue. In this study, we evaluated the detection limits at mRNA and protein level by approaching HBD2 from small tissue samples. METHODS: HT-29 colonic epithelial cells were incubated with proinflammatory cytokines before HBD2 mRNA was investigated by quantitative polymerase chain reaction. The HBD2 protein was assessed by Western blot analysis using HBD2 fused with enhanced green fluorescent protein (HBD2-EGFP). Purified HBD2 fused with the glutathione-S-transferase (GST-HBD2) was used to detect antibacterial activity in a densitometric assay. RESULTS: Interleukin (IL)-1ß induced HBD2 mRNA in HT-29 cells; however, tumor necrosis factor-α, IL-6 and IL-17 did not. The Western blot had a sensitivity of 1.5 pmol to detect recombinant HBD2, but did not detect HBD2 in either human intestinal or IL-1ß-treated HT-29 cells. HBD2-EGFP was detected by HBD2-specific Western blot within cell lysates and culture supernants of transfected HT-29 and primary cells. In nanomolar ranges, GST-HBD2 reduced bacterial growth. The HBD2 bioactivity depended on solution conditions, but not on the size of the fusion partner. CONCLUSION: The established fusion proteins provide excellent tools to evaluate expression patterns and antibacterial effects of HBD2 in human intestinal tissue samples.

[Complications and corrective surgery after ileal pouch-anal reconstruction?] / Komplikationen und Revisionsoperationen nach ileopouchanaler Rekonstruktion?

Proctocolectomy with ileal J­pouch-anal and rectal reconstruction is the standard surgical treatment for ulcerative colitis, selected cases of Crohn's disease, FAP and multilocular colon carcinoma. Although this treatment has been continuously developed over the last 40 years, the long-term success rate is 80-90% of the treated patients. The reasons for this are manifold: chronic pouchitis, incontinence, secondary diagnosis of Crohn's disease, fistulas, severe surgical complications, rectal stump left for too long, chronic abscess and surgical technical errors. This article deals with the control of acute complications and with the management of long-term complications. Some of the triggering complications for pouch failure do not generally imply failure of the method. A correction, closure of the fistula and in individual cases also a completely new pouch creation can restore a good pouch function in about 75% of cases. Various indications, techniques and results are presented.

[Kaposi sarcoma-a complication of treatment refractory ulcerative colitis]. / Das Kaposi-Sarkom ­ eine Komplikation bei therapierefraktärer Colitis ulcerosa.

We report on the incidental finding of Kaposi sarcoma of the colon in the setting of refractory ulcerative colitis treatment. The patient was under long-term immunosuppression with infliximab, vedolizumab, and prednisolone. Serologic analysis excluded human immunodeficiency virus (HIV) infection.

Rectal anatomy after rectopexy: cinedefecography versus MR-defecography.

BACKGROUND: Conventional defecography can reveal abnormalities in patients with evacuatory disorders. With fast dynamic MR imaging systems, MR-defecography has become possible, which does not expose patients to ionizing radiation. The purpose of this study was to assess the correlation of both methods after rectopexy. MATERIALS AND METHODS: Twenty-one consecutive patients underwent abdominal sigmoidectomy and rectopexy due to evacuatory disorders. Postoperatively, all patients were investigated by cineradiographic defecography. Fourteen patients underwent MR-defecography additionally. The results were screened for anorectal angle and pelvic floor position (rest, squeezing, and evacuation). The findings were depicted in Box plot analysis and compared with the Friedman-test. Descent of pelvic organs was also assessed. RESULTS: In MR-defecography, anorectal angle at rest was smaller than in conventional defecography, but there was no difference during squeezing and defecation. Concerning pelvic floor position, during squeezing, MR-defecography illustrated a lower perineum and a broader range of pelvic settings, but no difference at rest and during evacuation. In four patients, MR-defecography visualized a descent of the bladder. However, in four patients with complete evacuation in cineradiography and with no clinical complaints about incomplete evacuation, MR imaging showed deficient evacuation. Overall continence of patients was significantly improved through surgery, but there was no change in sphincter pressure, radial asymmetry, or sphincter length. CONCLUSIONS: In general, with respect to anorectal angle and perineal motility, both methods revealed consistent results. The concomitant depiction of structures in MR-defecography is helpful in the assessment of descent of pelvic organs and permits visualization of enteroceles. However, in 30% of patients, MR-defecography wrongly showed incomplete evacuation.

[Anastomotic techniques in surgery of Crohn's disease-Evidence and new developments]. / Anastomosentechniken in der M.-Crohn-Chirurgie ­ Evidenz und Neuentwicklungen.

Intestinal anastomoses in Crohn's disease are controversially discussed. In a comparison of the different types of anastomotic configuration the side-to-side anastomosis according to Kono­S seems to have the lowest recurrence rate. Neither the configuration of the anastomosis nor the suture material have an influence on the anastomotic leakage rate. The overall complication rate can be reduced by an amelioration of the nutritional status, a reduction of corticoids, pausing biologicals and an oral preoperative antibiotic prophylaxis.

Perianal Fistula-Associated Carcinoma in Crohn's Disease: A Multicentre Retrospective Case Control Study.

BACKGROUND AND AIMS: Carcinoma associated with perianal fistula in Crohn's disease is a pending threat for patients. This study aimed to improve understanding and facilitate development of diagnostic and therapeutic strategies. METHODS: A retrospective case-control study was conducted at four German hospitals. The analysis included 40 patients with proven malignancy associated with perianal Crohn's fistulas and 40 randomly selected controls with fistulizing perianal Crohn's disease. Differences between groups were analysed and multivariate calculations were performed to describe risk factors for oncological outcomes. RESULTS: Histology revealed adenocarcinoma in 33/40 patients and squamous cell carcinoma in 7/40 patients. Compared to fistula patients without carcinoma, patients with malignancies associated with fistula had a diagnosis of Crohn's disease at younger age. Crohn's disease lasted longer in patients with malignancy [25.8 ± 9.0 vs 19.6 ± 10.4; p = 0.006]. Fistula-related findings differed significantly between the two groups. Signs of complicated and severe fistulation including complex anatomy and chronic activity occurred significantly more often in patients with malignancy associated with fistula. Significant multivariate hazard ratios for overall mortality and progression-free survival were shown for histological type of cancer, metastatic disease and R1 resection. Overall survival was 45.1 ± 28.6 months and the 5-year survival rate was 65%. CONCLUSIONS: In patients with adenocarcinoma or squamous cell carcinoma associated with perianal fistula in Crohn's disease, fistula characteristics determine the risk of malignancy. Early diagnosis influences outcomes, while treatment of chronic fistula activity may be key to preventing malignancy. Expert multimodal therapy is paramount for successful treatment of perianal fistula-associated malignancies.

Comparison of strictureplasty and endoscopic balloon dilatation for stricturing Crohn's disease--review of the literature.

BACKGROUND: Stricturing Crohn's disease is accompanied by a high-risk for bowel resection and subsequent short bowel syndrome. Strictureplasty (SP) and endoscopic balloon dilatation (EBD) have been developed to prevent, or at least delay, the requirement for resection. The goal of this study was to compare the outcome of these two procedures with regard to complications and disease recurrence. METHODS: We conducted a MEDLINE literature search to give a current overview about the safety and efficacy of EBD and SP. RESULTS: The initial search yielded 744 articles. Case reports, reviews and meta-analyses were excluded. Finally, 63 articles (SP, 40 articles; EBD, 23 articles) were used for the review. None of the studies compared the two methods directly. A total of 2,532 patients (SP, n = 1,958; EBD, n = 574) were included. The incidence of perioperative complications after SP was 11% and the incidence of major complications was 5%. The median surgical recurrence rate was 24% after a median follow-up of 46 months. The median technical success for EBD was 90%. Major complications occurred in 3% of the cases. According to an intention-to-treat protocol, the median surgical recurrence rate was 27.6%. Per-protocol analysis revealed a median surgical recurrence rate of 21.4% after a median follow-up of 21 months. CONCLUSION: Due to the lack of comparable data, there is currently no reliable information on whether one treatment option is superior to the other. Regarding the limited applicability of EBD in strictures of the small bowel, only a controlled trial would provide evidence as a basis for clinical decision making in CD strictures that are potentially treatable by EBD and SP.

NALP expression in Paneth cells provides a novel track in IBD signaling.

PURPOSE: Paneth cells are part of the innate mucosal immunity of the gut with possible regulatory function. This study intends to identify the gene expression pattern of the orthotopic and metaplastic Paneth cells, searching for differences between metaplastic occurrence between Crohn's disease and ulcerative colitis. METHODS: Paneth cells were collected in RNAse-free conditions via micro dissection. RNA isolation and super amplification was followed by microarray analysis of whole genome expression activity of the orthotopic and metaplastic Paneth cells. Immunohistology of beta-catenin and Frizzled-5 receptor was performed. RESULTS: Histological analysis showed no morphological or secretory change (Frizzled-5 receptor and beta-catenin) in orthotopic and metaplastic Paneth cells. Microarray analysis indicated an increased, but not mutant activation of Wnt/beta-catenin signaling and firstly showed expression of NALP 1, 7, 8 and 11 in metaplastic Paneth cells. CONCLUSIONS: Paneth cells might play a NALP-mediated role in the pathogenesis of IBD.

Gangrenous intrathoracic appendicitis, a rare cause of right-sided chest pain: report of a case.

Diaphragmatic hernias are becoming increasingly common due to radiofrequency ablation of malignant liver tumors. Most patients eventually present with symptoms caused by bowel obstruction. A 54-year-old woman with pleuritic pain and fever had a right-sided enterothorax probably caused by hemihepatectomy several years before. The patient was diagnosed with perforated gangrenous intrathoracic appendicitis during an emergency laparotomy for suspected incarceration of her diaphragmatic hernia. She was treated with an appendectomy and suturing of her right hemidiaphragm. An acquired diaphragmatic hernia should therefore be surgically repaired as soon as it is diagnosed in order to avoid complications.

Expression of catalytic proteasome subunits in the gut of patients with Crohn's disease.

BACKGROUND AND PURPOSE: Activation of the transcription factor NF-kappaB by proteasomes and subsequent nuclear translocation of cytoplasmatic complexes play a crucial role in the intestinal inflammation. Proteasomes have a pivotal function in NF-kappaB activation by mediating degradation of inhibitory IkappaB proteins and processing of NF-kappaB precursor proteins. This study aims to analyze the expression of the human proteasome subunits in colonic tissue of patients with Crohn's disease. MATERIALS AND METHODS: Thirteen patients with Crohn's disease and 12 control patients were studied. The expression of immunoproteasomes and constitutive proteasomes was examined by Western blot analysis, immunoflourescence and quantitative real-time PCR. For real-time PCR, AK2C was used as housekeeping gene. RESULTS: The results indicate the influence of the intestinal inflammation on the expression of the proteasomes in Crohn's disease. Proteasomes from inflamed intestine of patients with Crohn's disease showed significantly increased expression of immunosubunits on both protein and mRNA levels. Especially, the replacement of the constitutive proteasome subunit beta1 by inducible immunosubunit beta1i was observed in patients with active Crohn's disease. In contrast, relatively low abundance of immunoproteasomes was found in control tissue. CONCLUSIONS: Our data demonstrate that in contrast to normal colonic tissue, the expression of immunoproteasomes was evidently increased in the inflamed colonic mucosa of patients with Crohn's disease. Thus, the chronic intestinal inflammation process in Crohn's disease leads to significant alterations of proteasome subsets.

Inflamed pouch mucosa possesses altered tight junctions indicating recurrence of inflammatory bowel disease.

BACKGROUND AND AIMS: The etiology of pouchitis after coloproctomucosectomy with ileal pouch-anal anastomosis in patients with ulcerative colitis is still unknown. Beside changes in luminal antigens, the immunological predisposition is assumed to be responsible. In previous electrophysiological studies, we showed that mucosal barrier and transport function in pouchitis is markedly reduced. Thus, the aim of the present study was to analyze barrier function on the molecular level. MATERIAL AND METHODS: Pouch biopsies of 36 ulcerative colitis patients were analyzed. Time points were (1) intraoperative immediately prior to ileal pouch-anal anastomosis (n = 13), (2) >1 year after ileostomy closure (pouch, n = 12), and (3) during pouchitis (n = 11). Control terminal ileum biopsies were obtained from eight patients undergoing hemicolectomy due to carcinoma. Expression of tight junction proteins was analyzed by Western blotting and confocal laser-scanning microscopy. To elucidate effects on epithelial barrier properties, impedance spectroscopy was performed in miniaturized Ussing chambers. RESULTS: In pouchitis, epithelial resistance was markedly reduced compared to non-inflamed pouch and control ileum. Expression of tight junction proteins claudin-1, 3, 4, 5, and 7 and occludin revealed differential expression regulation with the tightening tight junction protein claudin-1 being decreased and an increase of the pore-forming claudin-2, whereas other claudins remained constant. Morphometry indicated the mucosal surface to be unchanged. CONCLUSION: Pouchitis is characterized by a selective change of tight junction proteins in favor of opening the epithelial tight junction and, thus, the paracellular pathway, which contributes to the inflammatory process. This resembles changes in inflammatory bowel disease (IBD) and indicates IBD recurrence in pouchitis.

Early Surgery in Inflammatory Bowel Diseases Is a Better Option than Prolonged Conservative Treatment.

Early surgery is a very important aspect of treatment of inflammatory bowel diseases. In Crohn's disease, early surgery should be performed in emergencies, in refractory courses, and in special cases at the beginning of the disease if there is a stenosis limited to the terminal ileum. In ulcerative colitis, prolonged therapy with extended application of all available substances should be avoided. Every therapy with more than 2 biologicals endangers the patient. Low-grade intraepithelial neoplasia (IEN) should also be resected earlier due to a 23% risk of synchronous and metachronous high-grade IEN or cancer.

Permanently increased mucosal permeability in patients with backwash ileitis after ileoanal pouch for ulcerative colitis.

OBJECTIVE: Backwash ileitis (BI) has not been identified as a risk factor for pouchitis. The aim of this study was to investigate the barrier function of the ileoanal pouch depending on the presence of BI. The incidence of pouchitis in a population of ulcerative colitis patients with BI is also reported. MATERIAL AND METHODS: Biopsies were taken from 80 patients with ulcerative colitis: a) terminal ileum prior to pouch creation (pre-IAP); b) 16 months after ileostomy closure (intact pouch); and c) during pouchitis. Patients were stratified into the BI group and the non-BI (ØBI) group. Barrier function was determined in Ussing-chambers as epithelial resistance by impedance analysis and as mannitol permeability from (3)H-mannitol fluxes. Na(+)-glucose co-transport was measured as a change in short-circuit current (I(SC)) after addition of glucose. Relative risk of developing pouchitis was calculated by corrected chi(2) test. RESULTS: In 13/21 (BI/ØBI) pre-IAP patients, 23/37 (BI/ØBI) with an intact pouch, and 35/7 (BI/ØBI) with pouchitis, epithelial resistance in BI/ØBI was 13.5+/-1.6/14.3+/-0.9 Omega.cm(2) for pre-IAP, 12.7+/-1.3/16.8+/-1.2 Omega x cm(2) (p<0.05 BI versus ØBI) for the intact pouch, and 10.1+/-1.1/9.9+/-1.8 Omega x cm(2) for pouchitis (p<0.05 BI versus ØBI with an intact pouch). No differences were found for electrogenic chloride secretion and active Na(+)-glucose co-transport between BI/ØBI in the three groups. In patients with BI, pouchitis was more common (35 versus 7 patients, odds ratio 33.0 (95% CI 8.3-143.9; p<0.0001)). CONCLUSIONS: Ulcerative colitis patients with BI show impaired barrier function in the further course of the ileoanal pouch. Thus, BI has a long-term impact on epithelial barrier function.

Increased bacterial permeation in long-lasting ileoanal pouches.

BACKGROUND AND AIMS: Bacterial overgrowth appears to play an important role in the pathogenesis of ileoanal pouches. Therefore, the capability of bacterial permeation and its determinants is of great interest. The aim of this study was to examine bacterial permeation in the ileoanal pouch and to correlate the results with the degree of inflammation, the epithelial resistance, the mucosal transport function, and the age of the ileoanal pouches. MATERIALS AND METHODS: Biopsies were taken from 54 patients before colectomy (n = 13; preileal pouch-anal anastomosis [IPAA]), and closure of ileostomy (n = 7; deviation), <1 year after closure of ileostomy (n = 8; intact pouch I), >1 year after closure of ileostomy (n = 16; intact pouch II), in the case of pouchitis (n = 11), and in 11 controls. Tissues were mounted in a miniaturized Ussing chamber. Escherichia coli was added to the mucosal side of the Ussing chamber, and the permeation was proven by serosal presence of E. coli. Epithelial and subepithelial resistance was determined by transmural impedance analysis. Active Na-glucose cotransport and active Cl secretion were measured. Specimens were analyzed by fluorescent in situ hybridization with oligonucleotide probes targeting the bacterial 16s ribosomal RNA. The bacteria in and on the tissue were enumerated. RESULTS: Bacterial permeation occurred in 2 of 13 pre-IPAA, 2 of 7 deviations, 0 of 8 intact pouch I, 9 of 16 intact pouch II, 5 of 11 pouchitis specimens, and 0 of 11 ileum controls. The frequency of bacterial permeation in the intact pouch II group is higher than in the intact pouch I group (P < 0.001). Epithelial resistance, mannitol fluxes, electrogenic chloride secretion, sodium-glucose cotransport of the bacterially permeated specimens versus nonpermeated of the intact pouch II group, and the pouchitis group and subepithelial resistance remained unchanged. Intramural bacteria could be detected by fluorescence in situ hybridization mainly in long-lasting pouches, but there was no correlation with bacterial permeation. CONCLUSIONS: The long-lasting ileoanal pouch is associated with increased bacterial permeability. This is not correlated with a disturbed function of the pouch mucosa but could be a precursor of pouchitis.

The HIV protease inhibitors saquinavir, ritonavir, and nelfinavir induce apoptosis and decrease barrier function in human intestinal epithelial cells.

BACKGROUND AND AIMS: Diarrhoea is a frequent adverse effect of HIV protease inhibitors (PIs) which may be due to intestinal barrier disruption. We investigated whether tight junction dysregulation, apoptosis or necrosis are responsible for this epithelial damage. METHODS: Saquinavir, nelfinavir, and ritonavir were added to the mucosal or serosal side of HT-29/B6 colon cell monolayers. Transepithelial resistance was monitored for 72 h to assess epithelial barrier function. Apoptosis and necrosis were investigated by light and electron microscopy and quantified by nucleosome ELISA and LDH measurement, respectively. Tight junction components were analysed by Western blots of occludin and zonula occludens. Apoptosis induction in normal human intestinal epithelium was examined by measurement of poly(ADP-ribose) polymerase (PARP) cleavage in Western blots of mucosal tissue explants cultured with PIs for 24 h. RESULTS: HIV PIs decreased transepithelial resistance by more than 44% in HT-29/B6 monolayers. Histology revealed massive apoptotic body formation but no evidence for necrosis after PI treatment. Correspondingly, LDH release was lower than 0.2%/h of total LDH, independent of PI treatment, and nucleosomes were increased up to 22-fold after drug treatment versus control. Occludin and zonula occludens-1 expression in the membrane were not diminished. PARP cleavage increased in normal human intestinal tissue treated with PIs. CONCLUSIONS: PI-induced barrier disruption in intestinal epithelial cells is not due to necrosis or tight junction alterations, but to induction of massive apoptosis which may lead to leak-flux diarrhoea in vivo. Our findings suggest that induction of apoptosis by PIs could have potential for antitumour therapy.