Economic and Clinical Burden of Herpes Zoster Among Patients With Inflammatory Bowel Disease in the United States.

Background: Patients with ulcerative colitis (UC) or Crohn's disease (CD) are at increased risk of herpes zoster (HZ); however, relevant cost and healthcare resource utilization (HCRU) data are limited. Methods: We estimated HCRU (hospitalization, emergency department [ED], and outpatient visits) and costs in patients with UC or CD, with and without HZ, using administrative claims data (October 2015-February 2020). HCRU and costs (2020 US dollars) were compared at 1 month, 1 quarter, and 1 year after the index date, using propensity score adjustment and generalized linear models. Results: In total, 20 948 patients were included: UC+/HZ+ (n = 431), UC+/HZ- (n = 10 285), CD+/HZ+ (n = 435), and CD+/HZ- (n = 9797). Patients with HZ had higher all-cause HCRU rates and all-cause total healthcare costs relative to those without HZ. In the first month, adjusted incidence rate ratios (aIRRs) for hospitalizations and ED visits for patients with UC and HZ compared with UC alone were 2.87 (95% confidence interval [CI], 1.93-4.27) and 2.66 (95% CI,1.74-4.05), respectively; for those with CD and HZ, aIRRs were 3.34 (95% CI, 2.38-4.70) and 3.31 (95% CI, 2.32-4.71), respectively, compared with CD alone (all P < .001). Adjusted cost differences in UC and CD cohorts with HZ over the first month were $2189 and $3774, respectively, chiefly driven by higher inpatient costs. The incremental impact on HCRU and costs in cohorts with HZ predominantly occurred during the first quarter following diagnosis. Conclusions: HZ is associated with increased HCRU and costs in patients with UC and CD, especially shortly after diagnosis.

Incidence and risk of herpes zoster in patients with ulcerative colitis and Crohn's disease in the USA.

Background: Patients with inflammatory bowel disease (IBD) are at increased risk of herpes zoster (HZ). We evaluated the incidence of HZ in ulcerative colitis (UC) and Crohn's disease (CD) patients and compared this with HZ incidence in a non-IBD population. Methods: We conducted a retrospective cohort study (GSK study identifier: VEO-000043) of adults aged ≥18 years with UC and CD and without IBD who were identified from claims recorded in a US healthcare database between October 2015 and February 2020. Crude HZ incidence rates/1,000 person-years (PY) were calculated, and comparisons of HZ incidence rates between UC or CD and non-IBD cohorts were made using adjusted generalized linear models. Results: The study population comprised a total of 29,928 UC, 25,959 CD, and 11,839,329 non-IBD patients. Crude overall HZ incidence rates were 13.64/1,000 PY (UC), 15.94/1,000 PY (CD), and 7.95/1,000 PY (non-IBD). UC and CD patients had increased HZ incidence rates, with adjusted incidence rate ratios of 1.35 (95% confidence interval [CI], 1.26-1.44) and 1.66 (95% CI, 1.56-1.77), respectively, compared with non-IBD patients. Stratified analysis indicated increased relative rates of HZ in progressively younger age strata in the UC and CD patients compared with non-IBD patients. HZ incidence rates were higher in UC and CD patients who had previously received thiopurines or methotrexate, TNF-inhibitors, or corticosteroids than in UC and CD patients who did not take those medicines. Conclusion: UC and CD patients had increased HZ incidence rates compared with patients without IBD, demonstrating the importance of HZ prevention in IBD patients.

Adhesion-related kinase induction of migration requires phosphatidylinositol-3-kinase and ras stimulation of rac activity in immortalized gonadotropin-releasing hormone neuronal cells.

GnRH neurons migrate into the hypothalamus during development. Although migratory defects may result in disordered activation of the reproductive axis and lead to delayed or absent sexual maturation, specific factors regulating GnRH neuronal migration remain largely unknown. The receptor tyrosine kinase, adhesion-related kinase (Ark) (also known as Axl, UFO, and Tyro7), has been implicated in the migration of GnRH neuronal cells. Binding of its ligand, growth arrest-specific gene 6 (Gas6), promotes cytoskeletal remodeling and migration of NLT GnRH neuronal cells via Rac and p38 MAPK. Here, we examined the Axl effectors proximal to Rac in the signaling pathway. Gas6/Axl-induced lamellipodia formation and migration were blocked after phosphatidylinositol-3-kinase (PI3K) inhibition in GnRH neuronal cells. The p85 subunit of PI3K coimmunoprecipitated with Axl and was phosphorylated in a Gas6-sensitive manner. In addition, PI3K inhibition in GnRH neuronal cells diminished Gas6-induced Rac activation. Exogenous expression of a dominant-negative form of Ras also decreased GnRH neuronal lamellipodia formation, migration, and Rac activation. PI3K inhibition blocked Ras in addition to Rac activation and migration. In contrast, pharmacological blockade of the phospholipase C gamma effectors, protein kinase C or calcium/calmodulin protein kinase II, had no effect on Gas6/Axl signaling to promote Rac activation or stimulate cytoskeletal reorganization and migration. Together, these data show that the PI3K-Ras pathway is a major mediator of Axl actions upstream of Rac to induce GnRH neuronal cell migration.

Molecular mechanisms of gonadotropin-releasing hormone neuronal migration.

Gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment, migrate along olfactory nerves to the cribriform plate and then diverge caudally to the forebrain to reach their final destination in the hypothalamus. Here, GnRH neurons are dispersed in a network that synchronously releases GnRH in a pulsatile manner to activate pituitary gonadotropin production. Gonadotropins in turn promote gametogenesis and steroidogenesis from the gonad, ensuring reproductive competence. Failure of GnRH neurons to migrate normally results in deficient activation of the reproductive axis and delayed or absent pubertal maturation. The exact mechanisms that direct GnRH neuronal migration are under active investigation. This article will review new information concerning factors regulating GnRH neuronal migration and the intracellular signaling pathways involved in this process.

Adhesion-related kinase repression of gonadotropin-releasing hormone gene expression requires Rac activation of the extracellular signal-regulated kinase pathway.

Recent studies suggest that adhesion-related kinase (Ark) plays a role in gonadotropin-releasing hormone (GnRH) neuronal physiology. Ark promotes migration of GnRH neurons via Rac GTPase and concomitantly suppresses GnRH gene expression via homeodomain and myocyte enhancer factor-2 (MEF2) transcription factors. Here, we investigated the signaling cascade required for Ark inhibition of the GnRH promoter in GT1-7 GnRH neuronal cells. Ark repression was blocked by the MEK/ERK pathway inhibitor, PD98059, and dominant negative MEK1 but was unaffected by dominant negative Ras. Inhibitors of the Rho family GTPases, Clostridium difficile toxin B (Rho/Rac/Cdc42 inhibitor) and Clostridium sordellii lethal toxin (Rac/Cdc42 inhibitor), blocked Ark inhibition of GnRH transcription. Moreover, dominant negative Rac blunted both Ark activation of ERK and repression of the GnRH promoter, demonstrating an essential role for Rac in coupling Ark to ERK activation. Like Ark, a constitutively active mutant of Rac suppressed GnRH transcription in an ERK-dependent manner. Finally, Ark-mediated repression was significantly attenuated by a dominant negative MEF2C, whereas repression induced by constitutively active Rac was unaffected, indicating that MEF2 proteins are not targets of the Ark --> Rac --> MEK --> ERK cascade. The data suggest that Ark suppresses GnRH gene expression via the coordinated activation of a Rac --> ERK signaling pathway and a distinct MEF2- dependent mechanism.

Liganded androgen receptor interaction with beta-catenin: nuclear co-localization and modulation of transcriptional activity in neuronal cells.

A yeast two-hybrid assay was employed to identify androgen receptor (AR) protein partners in gonadotropin-releasing hormone neuronal cells. By using an AR deletion construct (AR-(Delta371-485)) as a bait, beta-catenin was identified as an AR-interacting protein from a gonadotropin-releasing hormone neuronal cell library. Immunolocalization of co-transfected AR and FLAG-beta-catenin demonstrated that FLAG-beta-catenin was predominantly cytoplasmic in the absence of androgen. In the presence of 5alpha-dihydrotestosterone, FLAG-beta-catenin completely co-localized to the nucleus with AR. This effect was specific to AR because liganded progesterone, glucocorticoid, or estrogen alpha receptors did not translocate FLAG-beta-catenin to the nucleus. Agonist-bound AR was required because the AR antagonists casodex and hydroxyflutamide failed to translocate beta-catenin. Time course experiments demonstrated that co-translocation occurred with similar kinetics. Nuclear co-localization was independent of the glycogen synthase kinase-3beta, p42/44 ERK mitogen-activated protein kinase, and phosphatidylinositol 3-kinase pathways because inhibitors of these pathways had no effect. Transcription assays demonstrated that liganded AR repressed beta-catenin/T cell factor-responsive reporter gene activity. Conversely, co-expression of beta-catenin/T cell factor repressed AR stimulation of AR-responsive reporter gene activity. Our data suggest that liganded AR shuttles beta-catenin to the nucleus and that nuclear interaction of AR with beta-catenin may modulate transcriptional activity in androgen target tissues.