Kathryn Mitchell

Transplantation of Human Pericyte Progenitor Cells Improves the Repair of Infarcted Heart Through Activation of an Angiogenic Program Involving Micro-RNA-132

Rationale: Pericytes are key regulators of vascular maturation, but their value for cardiac repair remains unknown. Objective: We investigated the therapeutic activity and mechanistic targets of saphenous vein-derived pericyte progenitor cells (SVPs) in a mouse myocardial infarction (MI) model. Methods and Results: SVPs have a low immunogenic profile and are resistant to hypoxia/starvation (H/S). Transplantation of SVPs into the peri-infarct zone of immunodeficient CD1/Foxn-1nu/nu or immunocompetent CD1 mice attenuated left ventricular dilatation and improved ejection fraction compared to vehicle. Moreover, SVPs reduced myocardial scar, cardiomyocyte apoptosis and interstitial fibrosis, improved myocardial blood flow and neovascularization, and attenuated vascular permeability. SVPs secrete vascular endothelial growth factor A, angiopoietin-1, and chemokines and induce an endogenous angiocrine response by the host, through recruitment of vascular endothelial growth factor B expressing monocytes. The association of donor- and recipient-derived stimuli activates the proangiogenic and prosurvival Akt/eNOS/Bcl-2 signaling pathway. Moreover, microRNA-132 (miR-132) was constitutively expressed and secreted by SVPs and remarkably upregulated, together with its transcriptional activator cyclic AMP response element-binding protein, on stimulation by H/S or vascular endothelial growth factor B. We next investigated if SVP-secreted miR-132 acts as a paracrine activator of cardiac healing. In vitro studies showed that SVP conditioned medium stimulates endothelial tube formation and reduces myofibroblast differentiation, through inhibition of Ras-GTPase activating protein and methyl-CpG-binding protein 2, which are validated miR-132 targets. Furthermore, miR-132 inhibition by antimiR-132 decreased SVP capacity to improve contractility, reparative angiogenesis, and interstitial fibrosis in infarcted hearts. Conclusion: SVP transplantation produces long-term improvement of cardiac function through a novel paracrine mechanism involving the secretion of miR-132 and inhibition of its target genes.

Dense core secretory vesicles revealed as a dynamic Ca2+ store in neuroendocrine cells with a vesicle-associated membrane protein aequorin chimaera

The role of dense core secretory vesicles in the control of cytosolic-free Ca2+ concentrations ([Ca2+]c) in neuronal and neuroendocrine cells is enigmatic. By constructing a vesicle-associated membrane protein 2–synaptobrevin.aequorin chimera, we show that in clonal pancreatic islet β-cells: (a) increases in [Ca2+]c cause a prompt increase in intravesicular-free Ca2+ concentration ([Ca2+]SV), which is mediated by a P-type Ca2+-ATPase distinct from the sarco(endo) plasmic reticulum Ca2+-ATPase, but which may be related to the PMR1/ATP2C1 family of Ca2+ pumps; (b) steady state Ca2+ concentrations are 3–5-fold lower in secretory vesicles than in the endoplasmic reticulum (ER) or Golgi apparatus, suggesting the existence of tightly bound and more rapidly exchanging pools of Ca2+; (c) inositol (1,4,5) trisphosphate has no impact on [Ca2+]SV in intact or permeabilized cells; and (d) ryanodine receptor (RyR) activation with caffeine or 4-chloro-3-ethylphenol in intact cells, or cyclic ADPribose in permeabilized cells, causes a dramatic fall in [Ca2+]SV. Thus, secretory vesicles represent a dynamic Ca2+ store in neuroendocrine cells, whose characteristics are in part distinct from the ER/Golgi apparatus. The presence of RyRs on secretory vesicles suggests that local Ca2+-induced Ca2+ release from vesicles docked at the plasma membrane could participate in triggering exocytosis.

Ryanodine Receptor Type I and Nicotinic Acid Adenine Dinucleotide Phosphate Receptors Mediate Ca2+ Release from Insulin-containing Vesicles in Living Pancreatic β-Cells (MIN6)

We have demonstrated recently (Mitchell, K. J., Pinton, P., Varadi, A., Tacchetti, C., Ainscow, E. K., Pozzan, T., Rizzuto, R., and Rutter, G. A. (2001)J. Cell Biol. 155, 41–51) that ryanodine receptors (RyR) are present on insulin-containing secretory vesicles. Here we show that pancreatic islets and derived β-cell lines express type I and II, but not type III, RyRs. Purified by subcellular fractionation and membrane immuno-isolation, dense core secretory vesicles were found to possess a similar level of type I RyR immunoreactivity as Golgi/endoplasmic reticulum (ER) membranes but substantially less RyR II than the latter. Monitored in cells expressing appropriately targeted aequorins, dantrolene, an inhibitor of RyR I channels, elevated free Ca2+ concentrations in the secretory vesicle compartment from 40.1 ± 6.7 to 90.4 ± 14.8 μm(n = 4, p < 0.01), while having no effect on ER Ca2+ concentrations. Furthermore, nicotinic acid adenine dinucleotide phosphate (NAADP), a novel Ca2+-mobilizing agent, decreased dense core secretory vesicle but not ER free Ca2+ concentrations in permeabilized MIN6 β-cells, and flash photolysis of caged NAADP released Ca2+ from a thapsigargin-insensitive Ca2+ store in single MIN6 cells. Because dantrolene strongly inhibited glucose-stimulated insulin secretion (from 3.07 ± 0.51-fold stimulation to no significant glucose effect;n = 3, p < 0.01), we conclude that RyR I-mediated Ca2+-induced Ca2+ release from secretory vesicles, possibly potentiated by NAADP, is essential for the activation of insulin secretion.

Patient initiated outpatient follow up in rheumatoid arthritis: six year randomised controlled trial.

Abstract Objectives To determine whether direct access to hospital review initiated by patients with rheumatoid arthritis would result in improved clinical and psychological outcome, reduced overall use of healthcare resources, and greater satisfaction with care than seen in patients receiving regular review initiated by a rheumatologist. Design Two year randomised controlled trial extended to six years. Setting Rheumatology outpatient department in teaching hospital. Participants 209 consecutive patients with rheumatoid arthritis for over two years; 68 (65%) in the direct access group and 52 (50%) in the control group completed the study (P = 0.04). Main outcome measures Clinical outcome: pain, disease activity, early morning stiffness, inflammatory indices, disability, grip strength, range of movement in joints, and bone erosion. Psychological status: anxiety, depression, helplessness, self efficacy, satisfaction, and confidence in the system. Number of visits to hospital physician and general practitioner for arthritis. Results Participants were well matched at baseline. After six years there was only one significant difference between the two groups for the 14 clinical outcomes measured (deterioration in range of movement in elbow was less in direct access patients). There were no significant differences between groups for median change in psychological status. Satisfaction and confidence in the system were significantly higher in the direct access group at two, four, and six years: confidence 9.8 v 8.4, 9.4 v 8.0, 8.7 v 6.9; satisfaction 9.3 v 8.3, 9.3 v 7.7, 8.9 v 7.1 (all P < 0.02). Patients in the direct access group had 38% fewer hospital appointments (median 8 v 13, P < 0.0001). Conclusions Over six years, patients with rheumatoid arthritis who initiated their reviews through direct access were clinically and psychologically at least as well as patients having traditional reviews initiated by a physician. They requested fewer appointments, found direct access more acceptable, and had more than a third fewer medical appointments. This radical responsive management could be tested in other chronic diseases.

Combined Intramyocardial Delivery of Human Pericytes and Cardiac Stem Cells Additively Improves the Healing of Mouse Infarcted Hearts Through Stimulation of Vascular and Muscular Repair

RATIONALE Optimization of cell therapy for cardiac repair may require the association of different cell populations with complementary activities. OBJECTIVE Compare the reparative potential of saphenous vein-derived pericytes (SVPs) with that of cardiac stem cells (CSCs) in a model of myocardial infarction, and investigate whether combined cell transplantation provides further improvements. METHODS AND RESULTS SVPs and CSCs were isolated from vein leftovers of coronary artery bypass graft surgery and discarded atrial specimens of transplanted hearts, respectively. Single or dual cell therapy (300 000 cells of each type per heart) was tested in infarcted SCID (severe combined immunodeficiency)-Beige mice. SVPs and CSCs alone improved cardiac contractility as assessed by echocardiography at 14 days post myocardial infarction. The effect was maintained, although attenuated at 42 days. At histological level, SVPs and CSCs similarly inhibited infarct size and interstitial fibrosis, SVPs were superior in inducing angiogenesis and CSCs in promoting cardiomyocyte proliferation and recruitment of endogenous stem cells. The combination of cells additively reduced the infarct size and promoted vascular proliferation and arteriogenesis, but did not surpass single therapies with regard to contractility indexes. SVPs and CSCs secrete similar amounts of hepatocyte growth factor, vascular endothelial growth factor, fibroblast growth factor, stem cell factor, and stromal cell-derived factor-1, whereas SVPs release higher quantities of angiopoietins and microRNA-132. Coculture of the 2 cell populations results in competitive as well as enhancing paracrine activities. In particular, the release of stromal cell-derived factor-1 was synergistically augmented along with downregulation of stromal cell-derived factor-1-degrading enzyme dipeptidyl peptidase 4. CONCLUSIONS Combinatory therapy with SVPs and CSCs may complementarily help the repair of infarcted hearts.

Radium-223 in metastatic castration resistant prostate cancer: Progression free survival and pain scores--Real-world single-institution experience.

250 Background: Radium-223 (Ra223) is a novel alpha-emitting radiopharmaceutical agent approved for use in patients with metastatic castration resistant prostate cancer (mCRPC) and bone metastases based on ALSYMPCA results. We report our early experience in this setting. Methods: 36 patients were treated with Ra223 from Feb 2014 - Aug 2015. The patients were planned to receive 6 injections at a dose of 50 kBq/kg every 4 weekly. The pain was assessed using the visual analogue score (VAS). The effect of 6 cycles of Ra223 on blood counts, serum alkaline phosphatase (SAP), PSA, VAS and progression free survival (PFS) were evaluated. Results: At baseline (BL) median age was 79years; 66% of patients were ECOG 0-1; median VAS was 6. 53% had received prior docetaxel. 18 patients (50%) received all the scheduled 6 cycles of Ra223. In these patients there was a significant reduction in the pain scores both after the first cycle and after 6 cycles compared to the BL score (p < 0.05 & p < 0.001, respectively). A 30% ...