Vascular incorporation of endothelial colony-forming cells is essential for functional recovery of murine ischemic tissue following cell therapy.

OBJECTIVE: Cord blood-derived human endothelial colony-forming cells (ECFCs) bear a high proliferative capacity and potently enhance tissue neovascularization in vivo. Here, we investigated whether the leading mechanism for the functional improvement relates to their physical vascular incorporation or perivascular paracrine effects and whether the effects can be further enhanced by dual-cell-based therapy, including mesenchymal stem cells (MSCs). METHODS AND RESULTS: ECFCs or MSCs were lentivirally transduced with thymidine kinase suicide gene driven by the endothelial-specific vascular endothelial growth factor 2 (kinase insert domain receptor) promoter and evaluated in a hindlimb ischemia model. ECFCs and MSCs enhanced neovascularization after ischemic events to a similar extent. Dual therapy using ECFCs and MSCs further enhanced neovascularization. Mechanistically, 3 weeks after induction of ischemia followed by cell therapy, ganciclovir-mediated elimination of kinase insert domain receptor(+) cells completely reversed the therapeutic effect of ECFCs but not that of MSCs. Histological analysis revealed that ganciclovir effectively eliminated ECFCs incorporated into the vasculature. CONCLUSIONS: Endothelial-specific suicide gene technology demonstrates distinct mechanisms for ECFCs and MSCs, with complete abolishment of ECFC-mediated effects, whereas MSC-mediated effects remained unaffected. These data strengthen the notion that a dual-cell-based therapy represents a promising approach for vascular regeneration of ischemic tissue.

Combination of injectable multiple growth factor-releasing scaffolds and cell therapy as an advanced modality to enhance tissue neovascularization.

OBJECTIVE: Vasculogenic progenitor cell therapy for ischemic diseases bears great potential but still requires further optimization for justifying its clinical application. Here, we investigated the effects of in vivo tissue engineering by combining vasculogenic progenitors with injectable scaffolds releasing controlled amounts of proangiogenic growth factors. METHODS AND RESULTS: We produced biodegradable, injectable polylactic coglycolic acid-based scaffolds releasing single factors or combinations of vascular endothelial growth factor, hepatocyte growth factor, and angiopoietin-1. Dual and triple combinations of scaffold-released growth factors were superior to single release. In murine hindlimb ischemia models, scaffolds releasing dual (vascular endothelial growth factor and hepatocyte growth factor) or triple combinations improved effects of cord blood-derived vasculogenic progenitors. Increased migration, homing, and incorporation of vasculogenic progenitors into the vasculature augmented capillary density, translating into improved blood perfusion. Most importantly, scaffold-released triple combinations including the vessel stabilizer angiopoietin-1 enhanced the number of perivascular smooth muscle actin(+) vascular smooth muscle cells, indicating more efficient vessel stabilization. CONCLUSIONS: Vasculogenic progenitor cell therapy is significantly enhanced by in vivo tissue engineering providing a proangiogenic and provasculogenic growth factor-enriched microenvironment. Therefore, combined use of scaffold-released growth factors and cell therapy improves neovascularization in ischemic diseases and may translate into more pronounced clinical effects.

Prostaglandin E positively modulates endothelial progenitor cell homeostasis: an advanced treatment modality for autologous cell therapy.

AIMS: The mobilization of endothelial progenitor cells (EPC) and their functioning in postnatal neovascularization are tightly regulated. To identify new modulators of EPC homeostasis, we screened biologically active prostaglandin E compounds for their effects on EPC production, trafficking and function. METHODS AND RESULTS: We found that EPC are a rich source for prostaglandin E(2) (PGE(2)), stimulating their number and function in an auto- and paracrine manner. In vivo blockade of PGE(2) production by selective cyclooxygenase-2 inhibition virtually abrogated ischemia-induced EPC mobilization demonstrating its crucial role in EPC homeostasis following tissue ischemia. Conversely, ex vivo treatment of isolated EPC with the clinically approved PGE(1) analogue alprostadil enhanced EPC number and function. These effects were mediated by increased expression of the chemokine receptor CXCR4 and were dependent on nitric oxide synthase activity. Most importantly, ex vivo PGE(1) pretreatment of isolated EPC significantly enhanced their neovascularization capacity in a murine model of hind limb ischemia as assessed by laser Doppler analysis, exercise stress test and immunohistochemistry. CONCLUSIONS: The conserved role for PGE in the regulation of EPC homeostasis suggests that ex vivo modulation of the prostaglandin pathway in isolated progenitor cells may represent a novel and safe strategy to facilitate cell-based therapies.

Thyroid Hormones and Vitamin D in Patients with Breast Cancer with Mutations in BRCA1 or BRCA2 Genes.

AIM: The thyroid hormones free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH) and vitamin D seem to be involved in the process of differentiation and proliferation of breast tissue. Little is known about these factors in breast cancer 1 and 2 (BRCA1/BRCA2)-mutation carriers with breast cancer (BC). The purpose of this investigation was to evaluate the association of thyroid gland function and vitamin D with BC in patients with BRCA mutations. PATIENTS AND METHODS: At the Department of Hereditary Breast and Ovarian Cancer of the Ludwig Maximilian University Hospital of Munich, 40 patients with BC (10 patients with mutations in the BRCA1 gene, 10 with mutations in the BRCA2 gene, and 20 without mutations, as control group) were selected for analysis of the following parameters: fT3, fT4, TSH and vitamin D. The primary diagnosis was made between 21 and 62 years of age. The patients were matched by age. Anamnestic data were evaluated concerning disorders of the thyroid gland and primary BC diagnosis. RESULTS: In patients with BC, BRCA mutations are not associated with thyroidal dysfunctions. A significantly increased level of vitamin D in BRCA2-mutation carriers compared to those without mutation (p=0.02) was detected. The grade of the tumors in the BRCA2 group was better than in those with mutation. BRCA1-mutation carriers had an increased incidence of primary BC diagnosis during pregnancy (30% vs. 0%) in comparison to those without mutation. CONCLUSION: No association between the thyroid hormones and BC in BRCA1/2-mutation carriers was found. Vitamin D was significantly elevated in BRCA2-mutation carriers and the observation of a better tumor grade in this group could be consistent with the ability of vitamin D to inhibit growth and induce differentiation.

Comparison of two surgical methods for the treatment of CIN: classical LLETZ (large-loop excision of the transformation zone) versus isolated resection of the colposcopic apparent lesion - study protocol for a randomized controlled trial.

BACKGROUND: In compliance with national and international guidelines, non-pregnant women with cervical intraepithelial neoplasia grade 3 should be treated by cervical conization. According to the definition of the large loop excision of the transformation zone (LLETZ) operation, the lesion needs to be resected, including the transformation zone. It is well known from the literature that the cone size directly correlates with the risk of preterm delivery in the course of a future pregnancy. Thus, it would be highly desirable to keep the cone dimension as small as possible while maintaining the same level of oncological safety. METHODS/DESIGN: The aim of this study is to analyze whether resection of the lesion only, without additional excision of the transformation zone, is equally as effective as the classical LLETZ operation regarding oncological outcome. We are performing this prospective, patient-blinded multicenter trial by randomly assigning women who need to undergo a LLETZ operation for cervical intraepithelial neoplasia grade 3 to either of the following two groups at a ratio of 1:1: (1) additional resection of the transformation zone or (2) resection of the lesion only. To evaluate equal oncological outcome, we are performing human papillomavirus (HPV) tests 6 and 12 months postoperatively. The study is designed to consider the lesion-only operation as oncologically not inferior if the rate of HPV high-risk test results is not higher than 5 % compared with the HPV high-risk rate of women undergoing the classical LLETZ operation. DISCUSSION: In case that non-inferiority of the "lesion-only" method can be demonstrated, this operation should eventually become standard treatment for all women at childbearing age due to the reduction in risk of preterm delivery. TRIAL REGISTRATION: German Clinical Trials Register (DRKS) Identifier: DRKS00006169 . Date of registration: 30 July 2014.

Adiponectin pretreatment counteracts the detrimental effect of a diabetic environment on endothelial progenitors.

OBJECTIVE: It has been shown that vascular progenitors from patients with diabetes are dysfunctional. However, therapeutic strategies to counteract their reduced functional capacity are still lacking. Because adiponectin has reported salutary effects on endothelial function, we investigated the functional effects of globular adiponectin (gAcrp), the active domain of adiponectin, on isolated endothelial colony-forming cells (ECFC). RESEARCH DESIGN AND METHODS: ECFC were isolated from peripheral blood of type 2 diabetic patients (dmECFC) and compared with ECFC of healthy young volunteers (yECFC) and nondiabetic age-matched control subjects (hECFC). Cells were treated with gAcrp for 48 h followed by assessment of cell counts, cell cycle analysis, and migration capacity. For in vivo evaluation, human ECFC were injected into normoglycemic or streptozotocin-induced hyperglycemic nu/nu mice after hind limb ischemia. RESULTS: Whereas dmECFC were functionally impaired compared with yECFC and hECFC, gAcrp significantly enhanced their in vitro proliferation and migratory activity. In vitro effects were significantly stronger in hECFC compared with dmECFC and were mediated through the cyclooxygenase-2 pathway. Most important, however, we observed a profound and sustained increase of the in vivo neovascularization in mice receiving gAcrp-pretreated dmECFC compared with untreated dmECFC under both normoglycemic and hyperglycemic conditions. CONCLUSIONS: Pretreatment of ECFC with gAcrp enhanced the functional capacity of ECFC in vitro and in vivo in normoglycemic and hyperglycemic environments. Therefore, preconditioning of dmECFC with gAcrp may be a novel approach to counteract their functional impairment in diabetes.