We have used conditional gene ablation to uncover a dramatic and unpredicted role for the winged-helix transcription factor Foxa2 (formerly HNF-3␤) in pancreatic ␤-cell differentiation and metabolism. Mice that lack Foxa2 specifically in ␤ cells (Foxa2 [Key Words: Hepatocyte nuclear factor; persistent hyperinsulinemic hypoglycemia of infancy; familial hyperinsulinism]

OBJECTIVE -Diabetes leads to protein kinase C (PKC)-␤ overactivation and microvascular dysfunction, possibly resulting in disordered skin microvascular blood flow (SkBF) and other changes observed in diabetic peripheral neuropathy (DPN) patients. We investigate the effects of the isoform-selective PKC-␤ inhibitor ruboxistaurin mesylate on neurovascular function and other measures of DPN.RESEARCH DESIGN AND METHODS -Endothelium-dependent and C fibermediated SkBF, sensory symptoms, neurological deficits, nerve fiber morphometry, quantitative sensory and autonomic function testing, nerve conduction studies, quality of life (using the Norfolk Quality-of-Life Questionnaire for Diabetic Neuropathy [QOL-DN]), and adverse events were evaluated for 20 placebo-and 20 ruboxistaurin-treated (32 mg/day) DPN patients (aged Ն18 years; with type 1 or type 2 diabetes and A1C Յ11%) during a randomized, doublemasked, single-site, 6-month study.RESULTS -Endothelium-dependent (ϩ78.2%, P Ͻ 0.03) and C fiber-mediated (ϩ56.4%, P Ͻ 0.03) SkBF at the distal calf increased from baseline to end point. Significant improvements from baseline within the ruboxistaurin group were also observed for the Neuropathy Total Symptom Score-6 (NTSS-6) (3 months Ϫ48.3%, P ϭ 0.01; end point Ϫ66.0%, P Ͻ 0.0006) and the Norfolk QOL-DN symptom subscore and total score (end point Ϫ41.2%, P ϭ 0.01, and Ϫ41.0, P ϭ 0.04, respectively). Between-group differences in baseline-to-end point change were observed for NTSS-6 total score (placebo Ϫ13.1%; ruboxistaurin Ϫ66.0%, P Ͻ 0.03) and the Norfolk QOL-DN symptom subscore (placebo Ϫ4.0%; ruboxistaurin Ϫ41.2%, P ϭ 0.041). No significant ruboxistaurin effects were demonstrated for the remaining efficacy measures. Adverse events were consistent with those observed in previous ruboxistaurin studies.CONCLUSIONS -In this cohort of DPN patients, ruboxistaurin enhanced SkBF at the distal calf, reduced sensory symptoms (NTSS-6), improved measures of Norfolk QOL-DN, and was well tolerated. Diabetes Care 30:896 -902, 2007

Enteric neurotransmitters can modulate the biodefensive functions of the intestinal mucosa, but their role in mucosal interactions with enteropathogens is not well defined. Here we tested the hypothesis that norepinephrine (NE) modulates interactions between enterohemorrhagic Escherichia coli O157:H7 (EHEC) and the colonic epithelium. Mucosal sheets from porcine distal colon were mounted in Ussing chambers. Drugs and an inoculum of either Shiga toxin-negative or -positive EHEC were added to the contraluminal and luminal bathing medium, respectively. After 90 min, adherent bacteria were quantified by an adherence assay and by immunohistochemical methods; short-circuit current (I(sc)) was measured continuously to assess changes in active ion transport. NE-treated tissues exhibited concentration-dependent increases in I(sc) and EHEC adherence. NE did not alter adherence of a rodent-adapted, noninfectious E. coli strain or two porcine-adapted non-O157 E. coli strains. The actions of NE on EHEC adherence but not I(sc) were prevented by the alpha-adrenergic antagonist yohimbine and the PKA activator Sp-8-bromoadenosine-3',5'-cyclic monophosphorothioate. Like NE, the PKA inhibitor Rp-8-bromoadenosine-3',5'-cyclic monophosphorothioate or indirectly acting sympathomimetic agents increased EHEC adherence. Nerve fibers immunoreactive for the NE-synthesizing enzymes tyrosine hydroxylase and dopamine beta-hydroxylase appeared to innervate the colonic epithelium. EHEC-like immunoreactivity on the colonic surface had the appearance of bacterial microcolonies and increased after NE treatment by a phentolamine-sensitive mechanism. Through interactions with alpha(2)-adrenergic receptors, NE appears to increase EHEC adherence to the colonic mucosa. Changes in sympathetic neural outflow may alter intestinal susceptibility to infection.

Peyer's patches (PP), a key component of the gut-associated lymphoid tissue, serve as the primary inductive sites for intestinal immunity. In the present study, we addressed the hypothesis that the morphological features of PP innervation are consistent with an immunomodulatory role for the enteric nervous system. Laser scanning confocal microscopy was used to collect images through large tissue volumes, yielding a three-dimensional perspective of the neuronal network superimposed on PP follicles from porcine jejunum and human ileum. Peptidergic nerve fibers were found in close apposition to immunocytes within PP subepithelial domes and the adjacent villi. The results suggest that nerve fibers in PP may participate in neuroimmune cross-talk within individual antigen-sampling sites as well as integrate information across multiple antigen-sampling sites.

Enteric neural activity modulates active transepithelial ion transport in the intestine. We investigated the neural circuits mediating neurogenic secretion in mucosal explants from porcine ileum. Transmural electrical stimulation increased short-circuit current, a measure of active ion transport, by 35 ± 2 µA/cm 2 . The neuronal Na + channel blocker saxitoxin, the muscarinic cholinergic receptor antagonist atropine, the 5-hydroxytryptamine 3 receptor antagonist tropisetron, and the cyclooxygenase inhibitor indomethacin inhibited this response. In addition, tropisetron inhibited the atropine-resistant portion of the response, and both atropine and indomethacin attenuated the saxitoxin-resistant component. Neurogenic secretion in porcine ileum appears to be mediated by tryptaminergic and prostanoid-sensitive cholinergic pathways.