Citations

Key Points Zebrafish flt3 plays an important role in the initiation of definitive hematopoietic stem cells. Expression of human FLT3-ITD activates endogenous flt3 signaling and induces myeloid expansion.

BackgroundPostmenopausal hormone therapy (HT) increases the risk of venous thrombosis and ischemic stroke.ObjectivesWe postulated that HT might increase the risk of ischemic stroke by promoting venous clots that travel to the brain through a right to left shunt (RLS).MethodsA total of 2,389 records were studied. After eliminating the premenopausal patients, and those with TIAs and non‐ischemic strokes, the medical records of 1846 postmenopausal women hospitalized at four institutions for ischemic stroke were reviewed to identify those who had undergone an adequate study to assess for RLS. The proportion of women with a shunt in users and non‐users of HT was compared in stroke patients and in a reference population consisting of postmenopausal women undergoing elective cardiac catheterization.ResultsThere were 363 (20%) records that had complete data and were included in the analysis. A shunt was more prevalent in patients with a cryptogenic stroke than in patients with a stroke of known cause (55/88 (63%) vs. 53/275 (19%), P < 0.001). In patients with a stroke of known cause, the frequency of a shunt was similar to that in reference women 31/136 (23%), and the proportion of women with a shunt was similar in non‐users and current users of HT (14% vs. 20%, P = 0.40). However, among patients with a cryptogenic stroke, the prevalence of a shunt was 1.5 times higher in current users than non‐users of HT (82% vs. 56%, P = 0.04).ConclusionsApproximately 23% of older women have a RLS. HT in these women may increase the risk of ischemic stroke by promoting paradoxical embolism. © 2014 Wiley Periodicals, Inc.

Lipid droplets (LDs) are lipid storage organelles that in hepatocytes may be catabolized by autophagy for use as an energy source, but the membrane-trafficking machinery regulating such a process is poorly characterized. We hypothesized that the large GTPase Dynamin 2 (Dyn2), well known for its involvement in membrane deformation and cellular protein trafficking, could orchestrate autophagy-mediated LD breakdown. Accordingly, depletion or pharmacologic inhibition of Dyn2 led to a substantial accumulation of LDs in hepatocytes. Strikingly, the targeted disruption of Dyn2 induced a dramatic four- to fivefold increase in the size of autolysosomes. Chronic or acute Dyn2 inhibition combined with nutrient deprivation stimulated the excessive tubulation of these autolysosomal compartments. Importantly, Dyn2 associated with these tubules along their length, and the tubules vesiculated and fragmented in the presence of functional Dyn2. These findings provide new evidence for the participation of the autolysosome in LD metabolism and demonstrate a novel role for dynamin in the function and maturation of an autophagic compartment.

ScopeAndrogen receptor (AR) signaling is critical for all aspects of prostate growth and tumorigenesis. The glucosinolate‐derived phenethyl isothiocyanate (PEITC) has recently been demonstrated to reduce the risk of prostate cancer (PCa) and inhibit PCa cell growth. We previously reported that p300/CBP‐associated factor (PCAF), a co‐regulator for AR, is upregulated in PCa cells through suppression of the mir‐17 gene. Here, we assessed the effects of PEITC on PCAF expression and AR‐regulated transcriptional activity in PCa cells.Methods and resultsUsing AR‐responsive LNCaP cells, we observed the inhibitory effects of PEITC on the dihydrotestosterone‐stimulated AR transcriptional activity and cell growth of PCa cells. Interestingly, overexpression of PCAF attenuated the inhibitory effects of PEITC on dihydrotestosterone‐stimulated AR transcriptional activity. Expression of PCAF was upregulated in PCa cells through suppression of miR‐17. PEITC treatment significantly decreased PCAF expression and promoted transcription of miR‐17 in LNCaP cells. Functional inhibition of miR‐17 attenuated the suppression of PCAF in cells treated by PEITC.ConclusionOur results indicate that PEITC inhibits AR‐regulated transcriptional activity and cell growth of PCa cells through miR‐17‐mediated suppression of PCAF, suggesting a new mechanism by which PEITC modulates PCa cell growth.

PurposeAutoantibodies are implicated in the pathogenesis of cardiovascular diseases and cardiac arrhythmias. In this pilot study, we tested the hypothesis that autoantibodies are present in patients with postural orthostatic tachycardia syndrome (POTS).Experimental designSeven control subjects (6 F:1 M, average age 36.1 years) and ten patients with the diagnosis of POTS (7 F: 3 M, average age 35.1 years) provided informed consent and 30 mL of venous blood. Human heart membrane proteins were resolved by 2DE and immunoblotted against purified IgGs from controls and patients.ResultsEighteen protein spots immunoreactive specifically against patient IgGs were detected and they were excised from gels, trypsin‐digested, and analyzed by nanoLC‐electrospray MS/MS. Forty unique proteins were identified and these include proteins that are associated with cardiac hypertrophy (mimecan, myozenin), cardiac remodeling (periostin), cardiomyopathy (desmin, desmoplakin), cell survival (laminin), structural integrity (filamin), chaperone proteins (crystalline, HSP70), mitochondrial enzymes, and channel proteins. Ingenuity Pathway Analysis showed multiple pathways were involved including those that regulate energy metabolism, redox, fibrosis, cardiac hypertrophy, and degeneration.Conclusions and clinical relevanceAutoantibodies are present in patients with POTS. These autoantibodies cross‐react with a wide range of cardiac proteins and may induce alterations in cardiac function. Autoimmune pathogenetic mechanisms should be further explored in these patients.

Abstract Because numerous chemotherapeutic agents exert their cytotoxic effects through generation of reactive oxygen species, the use of antioxidant supplements during treatment is controversial. There are published recommendations to suspend antioxidant supplement use during treatment, despite lack of empirical data from clinical studies; however, it is unclear if patients follow these recommendations. We examined use of multivitamins and vitamin supplements (MV/SP) during treatment for breast cancer, particularly in relation to physician recommendations. High-risk breast cancer patients (n=855) were queried regarding physician recommendations and use of MV/SP via self-administered questionnaires in an ancillary study embedded in a phase III trial of dose-dense compared to metronomic administration of doxorubicin/cyclophosphamide + paclitaxel (SWOG S0221). Of the 658 patients who reported discussing use of supplements during treatment with their physicians, 390 (59%) received no counseling regarding MV/SP use, 85 (13%) received recommendations not to take MV/SP, and 183 (28%) received recommendations to use MV/SP. MV/SP use during treatment was compared to use prior to diagnosis in relation to physician recommendations, with the reference group comprised of those receiving no recommendations. Of those using MV ≥ once/week before diagnosis, recommendations not to take MV/SP were associated with a tenfold reduction in MV use to &lt; once/week during treatment. (OR=10.0, 95% CI=3.7-27.0). MV use was less likely to decrease among patients receiving recommendations to use MV/SP (OR=0.23, 95% CI=0.12-0.44). Similar findings were observed among patients who reported use of vitamin C and vitamin E supplements ≥ once/week before diagnosis, with patients who were advised to take no supplements other than a MV more than 5 times as likely to decrease use of antioxidant supplements. MV use during treatment among previous non-users increased almost sixfold among those whose physicians recommended MV/SP use during treatment (OR=5.92, 95% CI=3.29-10.6). For those reporting vitamin C or vitamin E use &lt; once/week before diagnosis, patients whose physicians recommended MV/SP during treatment were more likely to increase their use of vitamin C (OR=2.05, 95% CI=1.00-4.19) and vitamin E (OR=5.28, 95% CI=2.24-12.4). In this study, physician recommendations were strongly associated with patient use of MV/SP during chemotherapy, regardless of the patient's frequency of use prior to diagnosis. These findings highlight the critical need to better understand the mechanisms by which antioxidants may influence chemotherapeutic outcomes, and to determine if supplement use affects toxicity and/or recurrence. Yearly follow-up in this ongoing study will allow us to assess the impact of MV/SP use treatment outcomes, providing a basis for physician recommendations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4681. doi:10.1158/1538-7445.AM2011-4681

Background Adrenomedullin (ADM) is a newly discovered vasodilating and natriuretic peptide that may play an important role in cardiorenal regulation. Although ADM was originally isolated from human pheochromocytoma, ADM-like immunoreactivity has also been widely detected in various tissues, including the cardiovascular system. Methods and Results In view of reports that ADM circulates in the body and that ADM gene and ADM-like immunoreactivity are present in the heart, the present study was designed to determine the plasma concentration of ADM in healthy subjects and in patients with congestive heart failure (CHF) and to investigate the immunohistochemical presence and localization of ADM in normal and failing human hearts. Plasma ADM concentration was 13.2±2.3 pg/mL in healthy subjects (n=11) and increased to 47.3±6.7 pg/mL in patients with CHF (n=11, P <.05 versus normal). Human cardiac tissues were obtained from five patients with end-stage CHF undergoing cardiac transplantation. Five normal donor hearts that were used for cardiac transplantation served as sources for normal atrial tissues. Normal ventricular myocardium was also obtained by endomyocardial biopsy from the right ventricles of these donor hearts immediately before cardiac transplantation. Positive immunostaining was detected within the myocardia in both atria and ventricles of healthy and severely failing human transplanted hearts and was more intense in the atria than in the ventricles. Although there were no significant differences in the intensity of immunoreactivity between normal and failing atria, ADM immunoreactivity was significantly more intense in the ventricular myocytes from failing hearts compared with normal hearts. Conclusions The present study demonstrates that plasma concentration of ADM is increased in patients with CHF and that ADM is present in the human heart. ADM immunoreactivity is markedly increased in the failing human ventricle, suggesting that ventricular ADM expression may be influenced by the circumstances associated with CHF. This supports a potential role for this newly identified vasoactive and natriuretic peptide, ADM, in the neurohumoral activation that characterizes human CHF.