The pathogenesis of ulcerative colitis (UC), a major type of inflammatory bowel disease, remains unknown. No model exists that adequately recapitulates the complexity of clinical UC. Here, we take advantage of induced pluripotent stem cells (iPSCs) to develop an induced human UC-derived organoid (iHUCO) model and compared it with the induced human normal organoid model (iHNO). Notably, iHUCOs recapitulated histological and functional features of primary colitic tissues, including the absence of acidic mucus secretion and aberrant adherens junctions in the epithelial barrier both in vitro and in vivo. We demonstrate that the CXCL8/CXCR1 axis was overexpressed in iHUCO but not in iHNO. As proof-of-principle, we show that inhibition of CXCL8 receptor by the small-molecule non-competitive inhibitor repertaxin attenuated the progression of UC phenotypes in vitro and in vivo. This patient-derived organoid model, containing both epithelial and stromal compartments, will generate new insights into the underlying pathogenesis of UC while offering opportunities to tailor interventions to the individual patient.

In sporadic colon cancer, colon cancer stem cells (CCSCs) initiate tumorigenesis and may contribute to late disease recurrences and metastases. We previously showed that aldehyde dehydrogenase (ALDH) activity (as indicated by the ALDEFLUOR® assay) is an effective marker for highly enriching CCSCs for further evaluation. Here, we used comparative transcriptome and proteome approaches to identify signaling pathways overrepresented in the CCSC population. We found overexpression of several components of the phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway, including PI3KR2, a regulatory subunit of PI3K. LY294002, a PI3K inhibitor, defined the contribution of the PI3K/Akt/mTOR signaling pathway in CCSCs. LY294002-treated CCSCs showed decreases in proliferation, sphere formation and self-renewal, in phosphorylation-dependent activation of Akt, and in expression of cyclin D1. Inhibition of PI3K in vivo reduced tumorigenicity, increased detection of cleaved caspase 3, an indicator of apoptosis, and elevated expression of the inflammatory chemokine, CXCL8. Collectively, these results indicate that PI3K/Akt/mTOR signaling controls CCSC proliferation and CCSC survival, and suggests that it would be useful to develop therapeutic agents that target this signaling pathway.

A high-pressure liquid chromatographic method is described for the analysis of a wide range of cephalosporin congeners, using only three reagents for extraction and drug analysis. Plasma was treated with cold methanol-0.1 M sodium acetate to precipitate protein. Cephalosporins were resolved on a C-18 reverse-phase column, utilizing a mobile phase of various percentages of 0.01 M sodium acetate and acetonitrile-methanol. Compounds analyzed included cephalexin, cefamandole, cephalothin, cefotaxime, cefazolin, cephaloridine, cefoxitin, cefaclor, cephapirin, and cefoperazone. Each antibiotic demonstrated excellent linearity throughout the therapeutic range. The method of standard additions revealed recoveries of 93 to 101%, with detection limits ranging from 0.2 to 1.0 ,ug/ml for these drugs. Retention times ranged from 4 to 6 min. This method offers a rapid and simple means by which this group of cephalosporins may be reliably quantitated.The application of high-pressure liquid chromatography (HPLC) to the analysis of antibiotics introduces a powerful tool for therapeutic drug monitoring as well as clinical research (1). The advantages of short turnaround time, method reliability, method sensitivity, and drug specificity justify the use of HPLC for various groups of antibiotics (8,15).Original reports of cephalosporin quantitation by HPLC typically describe the analysis of a single cephalosporin in biological fluid (2,7,9,10,13,14). Each of these methods presents a unique preparatory and chromatographic protocol for a single cephalosporin or its metabolite or both. The analysis of a wide range of different cephalosporins would be complicated by extensive method changeover of extraction procedure, mobile phase, stationary phase, and UV detection wavelength (6, 15). Research on a large class of compounds such as the cephalosporins would be expedited by the availability of a readily adjustable method of analysis that used a limited number of reagents.With this goal in mind, we describe the development of a reverse-phase HPLC method for the analysis of cephalothin, cephaloridine, cefaclor, cefamandole, cefazolin, cephalexin, cefoperazone, cephapirin, cefoxitin, and cefotaxime in human plasma. MATERIALS AND METHODSCephalosporin standards were prepared fresh in distilled deionized water or 0.45 M phosphate buffer, pH 6.8 (according to the manufacturers' reconstitution instructions), on the day of analysis. Internal standards were prepared fresh daily in absolute methanol at a concentration approximating the mean of the therapeutic range (Tables 1 and 2 All experiments were performed on antibiotic-spiked human plasma from the hospital blood bank. Plasma (0.3 ml) was combined with an equal volume of ice-cold 70% absolute methanol with internal standard-30% 0.1 M sodium acetate, pH 5.2. This mixture was vortexed for 30 s and incubated at -20°C for 10 min. The specimens were centrifuged at 1,500 x g for 10 min, and 10 ,ul of the resulting supernatant was used for analysis.Chromatography was performed at room temperature sin...

Colitis-associated cancer is a relatively rare form of cancer with an unclear pathogenesis. Colitis-associated cancer serves as a prototype of inflammation-associated cancers. Advanced colonoscopic techniques are considered standard of care for surveillance in patients with long-standing colitis, especially those with other risk factors, including sclerosing cholangitis and a family history of colorectal cancer. When colitis-associated cancer is diagnosed, the standard operation involves total proctocolectomy. Restorative procedures and surveillance after colectomy require special considerations. In these contexts, new 3-dimensional human models may be used to usher in personalized medicine.

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