Acetylation and deacetylation of histones and other proteins depends on histone acetyltransferases and histone deacetylases (HDACs) activities, leading to either positive or negative gene expression. HDAC inhibitors have uncovered a role for HDACs in proliferation, apoptosis and inflammation. However, little is known of the roles of specific HDACs in intestinal epithelial cells (IEC). We investigated the consequences of ablating both HDAC1 and HDAC2 in murine IECs. Floxed Hdac1 and Hdac2 homozygous mice were crossed with villin-Cre mice. Mice deficient in both IEC HDAC1 and HDAC2 weighed less and survived more than a year. Colon and small intestinal sections were stained with hematoxylin and eosin, or with Alcian blue and Periodic Acid Schiff for goblet cell identification. Tissue sections from mice injected with BrdU for 2 h, 14 h and 48 h were stained with anti-BrdU. To determine intestinal permeability, 4-kDa FITC-labeled dextran was given by gavage for 3 h. Microarray analysis was performed on total colon RNAs. Inflammatory and IEC-specific gene expression was assessed by Western blot or semi-quantitative RT-PCR and qPCR with respectively total colon protein and total colon RNAs. HDAC1 and HDAC2-deficient mice displayed: 1) increased migration and proliferation, with elevated cyclin D1 expression and phosphorylated S6 ribosomal protein, a downstream mTOR target; 2) tissue architecture defects with cell differentiation alterations, correlating with reduction of secretory Paneth and goblet cells in jejunum and goblet cells in colon, increased expression of enterocytic markers such as sucrase-isomaltase in the colon, increased expression of cleaved Notch1 and augmented intestinal permeability; 3) loss of tissue homeostasis, as evidenced by modifications of claudin 3 expression, caspase-3 cleavage and Stat3 phosphorylation; 4) chronic inflammation, as determined by inflammatory molecular expression signatures and altered inflammatory gene expression. Thus, epithelial HDAC1 and HDAC2 restrain the intestinal inflammatory response, by regulating intestinal epithelial cell proliferation and differentiation.

No abstract

BackgroundLevofloxacin is a broad‐spectrum antibiotic of the fluoroquinolone class used in the paediatric population to treat resistant bacterial infections. Because no commercial option exists, a stable liquid formulation of this antibiotic made with accessible vehicles would be useful.AimThe aim of this study was to develop and assess the stability of levofloxacin suspensions made from commercially available tablets and three different accessible vehicles.MethodsLevofloxacin suspensions (50 mg/mL) were compounded using two different commercially available tablets (from Apotex; Toronto, ON, Canada and Sandoz; Boucherville, QC, Canada) and three different vehicles (Ora‐Blend, Oral‐Mix; Medisca, Saint‐Laurent, QC, Canada and Simple Syrup (SS); Laboratoire Atlas Inc., Anjou, QC, Canada). Suitable suspensions in Ora‐Blend and Oral‐Mix were stored at room temperature (25°C) as well as under refrigeration (5°C) in amber plastic bottles for 90 days. Suspensions made with SS were only stored at 25°C because of sugar crystallisation at 5°C. Suspension concentrations were assessed by HPLC.ResultsSuspensions using Apotex levofloxacin tablets produced unsuitable high‐foaming, phase‐separated, non‐homogeneous suspension products in all vehicles tested that were therefore not tested for stability. Levofloxacin suspensions prepared using Sandoz tablets remained chemically and physically stable for 3 months, with >96% recovery according to United States Pharmacopeia criteria (90%–110%) in all three vehicles.ConclusionThe results show that the choice of generic levofloxacin tablets is important when preparing homogeneous suspensions. All three vehicles could be used to prepare levofloxacin suspensions using Sandoz tablets that were physically and chemically stable for 3 months.