Faculty Bibliography

INTRODUCTION/BACKGROUND:Microbial translocation has been implicated as a contributing factor to the heightened immune activation observed during HIV-1 disease progression. When examined in a longitudinal study of HIV-1 seroconverters in Rakai, Uganda, microbial translocation was not associated with HIV-1 disease progression. However, the role of general immune activation in HIV disease progression in this population was not fully examined. METHODS:Longitudinal serum samples of HIV-1 seroconverters in three HIV-1 disease progression groups [long-term nonprogressors (LTNP), standard progressors (SP), and rapid progressors (RP)] from Rakai, Uganda, were tested for levels of C-reactive protein (CRP), a marker for immune activation. RESULTS:CRP levels significantly increased in the SP group (P < 0.0001) but not in the RP group or the LTNP group. CRP levels during the first year post-HIV seroconversion in the RP group were significantly higher than those observed in the LTNP group (P < 0.05). For the entire population, CRP levels negatively correlated with lipopolysaccharide levels (P < 0.05) and were not associated with endotoxin antibody levels. CONCLUSIONS:This study suggests that in this population, increased immune activation is significantly associated with HIV-1 disease progression but not microbial translocation.

AIMS/OBJECTIVE:Myostatin inhibits myoblast differentiation/proliferation and may play a role in heart failure (HF) and reverse remodelling after left ventricular assist device (LVAD) support. This study sought to characterize myostatin expression and activation in advanced HF before and after LVAD support. METHODS AND RESULTS/RESULTS:Left ventricular tissue pairs were collected at LVAD implantation (core) and at cardiac transplantation/LVAD explantation in patients with advanced ischaemic (ICM-ischaemic cardiomyopathy) and non-ischaemic (DCM-dilated cardiomyopathy) HF. Normal cardiac tissue (control) was obtained from hearts not placed for transplantation. Serum was collected independently from patients with stable DCM HF and from healthy controls. Full-length and cleaved propeptide myostatin levels were quantified by western blot analysis. Dilated cardiomyopathy propeptide levels at core were significantly higher than control and significantly increased after LVAD support. Ischaemic cardiomyopathy propeptide levels were higher than control, but did not change after LVAD support. No changes in full-length levels were seen. Serum myostatin levels were significantly higher in DCM HF patients than in healthy controls. CONCLUSION/CONCLUSIONS:This is the first clinical evidence that myostatin activation is increased in HF. Myostatin may affect cardiac hypertrophy and may mediate regression of cellular hypertrophy after mechanical unloading.

Wnt/β-catenin signaling is critically involved in metazoan development, stem cell maintenance and human disease. Using Xenopus laevis egg extract to screen for compounds that both stabilize Axin and promote β-catenin turnover, we identified an FDA-approved drug, pyrvinium, as a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). We show pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. CK1α knockdown abrogates the effects of pyrvinium on the Wnt pathway. In addition to its effects on Axin and β-catenin levels, pyrvinium promotes degradation of Pygopus, a Wnt transcriptional component. Pyrvinium treatment of colon cancer cells with mutation of the gene for adenomatous polyposis coli (APC) or β-catenin inhibits both Wnt signaling and proliferation. Our findings reveal allosteric activation of CK1α as an effective mechanism to inhibit Wnt signaling and highlight a new strategy for targeted therapeutics directed against the Wnt pathway.

Evidence from Drosophila and cultured cell studies supports a role for heterotrimeric guanosine triphosphate-binding proteins (G proteins) in Wnt signaling. Wnt inhibits the degradation of the transcriptional regulator beta-catenin. We screened the alpha and betagamma subunits of major families of G proteins in a Xenopus egg extract system that reconstitutes beta-catenin degradation. We found that Galpha(o), Galpha(q), Galpha(i2), and Gbetagamma inhibited beta-catenin degradation. Gbeta(1)gamma(2) promoted the phosphorylation and activation of the Wnt co-receptor low-density lipoprotein receptor-related protein 6 (LRP6) by recruiting glycogen synthase kinase 3 (GSK3) to the membrane and enhancing its kinase activity. In both a reporter gene assay and an in vivo assay, c-betaARK (C-terminal domain of beta-adrenergic receptor kinase), an inhibitor of Gbetagamma, blocked LRP6 activity. Several components of the Wnt-beta-catenin pathway formed a complex: Gbeta(1)gamma(2), LRP6, GSK3, axin, and dishevelled. We propose that free Gbetagamma and Galpha subunits, released from activated G proteins, act cooperatively to inhibit beta-catenin degradation and activate beta-catenin-mediated transcription.

Novel H1N1 influenza virus infected more than 43,000 people, killed 353 and spread to more than 122 countries within a few months. The World Health Organization declared a stage 6 worldwide pandemic. Healthcare workers and hospitals prepared for the worst. Federal and State regulations provided the legal framework to allow for the preparation and planning for a pandemic. One State had mandated both seasonal and Novel H1N1 vaccination of all healthcare workers in an effort to reduce transmission of influenza in healthcare facilities. The US Supreme Court decided in 1905 that the police power of the State permitted a State Department of Health the leeway to mandate vaccination in the face of a contagious disease. Law suits were filed, and a temporary injunction barring mandatory vaccination was entered by the court. While awaiting a court hearing, the mandatory vaccination regulation was rescinded because of the shortage of both seasonal and H1N1 vaccine. Based on the current state of the pandemic and the shortage of vaccination, it is possible that the US Supreme Court would uphold mandatory vaccination in a pandemic.

BACKGROUND: Studies have demonstrated that villous atrophy in celiac disease is patchy and have suggested that duodenal bulb biopsies aid in diagnosis. OBJECTIVE: To determine the role of the addition of duodenal bulb biopsies to distal duodenum (D2) biopsies in the diagnosis of celiac disease. DESIGN: Prospective, case-control study. SETTING: Tertiary referral hospital. PATIENTS: Patients undergoing upper endoscopy with biopsy for diagnosis or follow-up of celiac disease and control patients. INTERVENTIONS: Blinded review of duodenal biopsy samples. MAIN OUTCOME MEASUREMENTS: Increasing the yield as well as accuracy of the histologic diagnosis of celiac disease with the addition of bulb biopsies. RESULTS: Of 128 patients enrolled in the study, 67 had celiac disease. Of 1079 biopsy specimens, only 319 (30%) were adequate for complete histologic analysis, resulting in 40 celiac patients and 40 control patients for analysis. Of the 40 celiac patients, 35 (87.5%) had atrophy in either the bulb or D2, 30 (75%) exhibited atrophy at both sites with an identical grade of atrophy seen in 18 patients (45%). Fourteen patients (35%) had identical types of Marsh lesions in both biopsy sites. Twelve patients (30%) had atrophy detected in the bulb, D2, or both, but lacked intraepithelial lymphocytes and thus could not be assigned a Marsh grade. Five patients (13%) had a diagnosis of celiac disease based on findings in the bulb biopsy only. LIMITATIONS: Small sample size and study performed in an academic medical center. CONCLUSIONS: Our study confirms the patchy nature of villous atrophy as well as intraepithelial lymphocytosis in biopsy specimens from individuals with celiac disease. Adding duodenal bulb biopsies to our sampling regimen increased the diagnostic yield of celiac disease.