Elizabeth Wise

Detailed analysis of bone marrow from patients with ischemic heart disease and left ventricular dysfunction BM CD34, CD11b, and clonogenic capacity as biomarkers for clinical outcomes

Rationale: Bone marrow (BM) cell therapy for ischemic heart disease (IHD) has shown mixed results. Before the full potency of BM cell therapy can be realized, it is essential to understand the BM niche after acute myocardial infarction (AMI). Objective: To study the BM composition in patients with IHD and severe left ventricular (LV) dysfunction. Methods and Results: BM from 280 patients with IHD and LV dysfunction were analyzed for cell subsets by flow cytometry and colony assays. BM CD34+ cell percentage was decreased 7 days after AMI (mean of 1.9% versus 2.3%–2.7% in other cohorts; P<0.05). BM-derived endothelial colonies were significantly decreased (P<0.05). Increased BM CD11b+ cells associated with worse LV ejection fraction (LVEF) after AMI (P<0.05). Increased BM CD34+ percentage associated with greater improvement in LVEF (+9.9% versus +2.3%; P=0.03, for patients with AMI and +6.6% versus −0.02%; P=0.021 for patients with chronic IHD). In addition, decreased BM CD34+ percentage in patients with chronic IHD correlated with decrement in LVEF (−2.9% versus +0.7%; P=0.0355). Conclusions: In this study, we show a heterogeneous mixture of BM cell subsets, decreased endothelial colony capacity, a CD34+ cell nadir 7 days after AMI, a negative correlation between CD11b percentage and postinfarct LVEF, and positive correlation of CD34 percentage with change in LVEF after cell therapy. These results serve as a possible basis for the small clinical improvement seen in autologous BM cell therapy trials and support selection of potent cell subsets and reversal of comorbid BM impairment. Clinical Trial Registrations: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00684021, NCT00684060, and NCT00824005Rationale: Bone marrow (BM) cell therapy for ischemic heart disease (IHD) has shown mixed results. Before the full potency of BM cell therapy can be realized, it is essential to understand the BM niche after acute myocardial infarction (AMI). Objective: To study the BM composition in patients with IHD and severe left ventricular (LV) dysfunction. Methods and Results: BM from 280 patients with IHD and LV dysfunction were analyzed for cell subsets by flow cytometry and colony assays. BM CD34+ cell percentage was decreased 7 days after AMI (mean of 1.9% versus 2.3%–2.7% in other cohorts; P <0.05). BM-derived endothelial colonies were significantly decreased ( P <0.05). Increased BM CD11b+ cells associated with worse LV ejection fraction (LVEF) after AMI ( P <0.05). Increased BM CD34+ percentage associated with greater improvement in LVEF (+9.9% versus +2.3%; P =0.03, for patients with AMI and +6.6% versus −0.02%; P =0.021 for patients with chronic IHD). In addition, decreased BM CD34+ percentage in patients with chronic IHD correlated with decrement in LVEF (−2.9% versus +0.7%; P =0.0355). Conclusions: In this study, we show a heterogeneous mixture of BM cell subsets, decreased endothelial colony capacity, a CD34+ cell nadir 7 days after AMI, a negative correlation between CD11b percentage and postinfarct LVEF, and positive correlation of CD34 percentage with change in LVEF after cell therapy. These results serve as a possible basis for the small clinical improvement seen in autologous BM cell therapy trials and support selection of potent cell subsets and reversal of comorbid BM impairment. Clinical Trial Registrations: URL: . Unique identifiers: [NCT00684021][1], [NCT00684060][2], and [NCT00824005][3] # Novelty and Significance {#article-title-31} [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00684021&atom=%2Fcircresaha%2F115%2F10%2F867.atom [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00684060&atom=%2Fcircresaha%2F115%2F10%2F867.atom [3]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00824005&atom=%2Fcircresaha%2F115%2F10%2F867.atom

Developing mechanistic insights into cardiovascular cell therapy: Cardiovascular Cell Therapy Research Network Biorepository Core Laboratory rationale.

Moderate improvements in cardiac performance have been reported in some clinical settings after delivery of bone marrow mononuclear cells to patients with cardiovascular disease. However, mechanistic insights into how these cells impact outcomes are lacking. To address this, the National Heart, Lung and Blood Institute (NHLBI) Cardiovascular Cell Therapy Research Network (CCTRN) established a Biorepository Core for extensive phenotyping and cell function studies and storing bone marrow and peripheral blood for 10 years. Analyzing cell populations and cell function in the context of clinical parameters and clinical outcomes after cell or placebo treatment empower the development of novel diagnostic and prognostics. Developing such biomarkers that define the safety and efficacy of cell therapy is a major Biorepository aim.

Identification of bone marrow cell subpopulations associated with improved functional outcomes in patients with chronic left ventricular dysfunction: An embedded cohort evaluation of the FOCUS-CCTRN trial

In the current study, we sought to identify bone marrow-derived mononuclear cell (BM-MNC) subpopulations associated with a combined improvement in left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), and maximal oxygen consumption (VO2 max) in patients with chronic ischemic cardiomyopathy 6 months after receiving transendocardial injections of autologous BM-MNCs or placebo. For this prospectively planned analysis, we conducted an embedded cohort study comprising 78 patients from the FOCUS-Cardiovascular Cell Therapy Research Network (CCTRN) trial. Baseline BM-MNC immunophenotypes and progenitor cell activity were determined by flow cytometry and colony-forming assays, respectively. Previously stable patients who demonstrated improvement in LVEF, LVESV, and VO2 max during the 6-month course of the FOCUS-CCTRN study (group 1, n = 17) were compared to those who showed no change or worsened in one to three of these endpoints (group 2, n = 61) and to a subset of patients from group 2 who declined in all three functional endpoints (group 2A, n = 11). Group 1 had higher frequencies of B-cell and CXCR4+ BM-MNC subpopulations at study baseline than group 2 or 2A. Furthermore, patients in group 1 had fewer endothelial colony-forming cells and monocytes/macrophages in their bone marrow than those in group 2A. To our knowledge, this is the first study to show that in patients with ischemic cardiomyopathy, certain bone marrow-derived cell subsets are associated with improvement in LVEF, LVESV, and VO2 max at 6 months. These results suggest that the presence of both progenitor and immune cell populations in the bone marrow may influence the natural history of chronic ischemic cardiomyopathy—even in stable patients. Thus, it may be important to consider the bone marrow composition and associated regenerative capacity of patients when assigning them to treatment groups and evaluating the results of cell therapy trials.

Myxoma virus suppresses proliferation of activated T lymphocytes yet permits oncolytic virus transfer to cancer cells

Allogeneic hematopoietic cell transplant (allo-HCT) can be curative for certain hematologic malignancies, but the risk of graft-versus-host disease (GVHD) is a major limitation for wider application. Ideally, strategies to improve allo-HCT would involve suppression of T lymphocytes that drive GVHD while sparing those that mediate graft-versus-malignancy (GVM). Recently, using a xenograft model, we serendipitously discovered that myxoma virus (MYXV) prevented GVHD while permitting GVM. In this study, we show that MYXV binds to resting, primary human T lymphocytes but will only proceed into active virus infection after the T cells receive activation signals. MYXV-infected T lymphocytes exhibited impaired proliferation after activation with reduced expression of interferon-γ, interleukin-2 (IL-2), and soluble IL-2Rα, but did not affect expression of IL-4 and IL-10. MYXV suppressed T-cell proliferation in 2 patterns (full vs partial) depending on the donor. In terms of GVM, we show that MYXV-infected activated human T lymphocytes effectively deliver live oncolytic virus to human multiple myeloma cells, thus augmenting GVM by transfer of active oncolytic virus to residual cancer cells. Given this dual capacity of reducing GVHD plus increasing the antineoplastic effectiveness of GVM, ex vivo virotherapy with MYXV may be a promising clinical adjunct to allo-HCT regimens.

Virotherapy Using Myxoma Virus Prevents Lethal Graft-versus-Host Disease following Xeno-Transplantation with Primary Human Hematopoietic Stem Cells

Graft-versus-host disease (GVHD) is a potentially lethal clinical complication arising from the transfer of alloreactive T lymphocytes into immunocompromised recipients. Despite conventional methods of T cell depletion, GVHD remains a major challenge in allogeneic hematopoietic cell transplant. Here, we demonstrate a novel method of preventing GVHD by ex vivo treatment of primary human hematopoietic cell sources with myxoma virus, a rabbit specific poxvirus currently under development for oncolytic virotherapy. This pretreatment dramatically increases post-transplant survival of immunocompromised mice injected with primary human bone marrow or peripheral blood cells and prevents the expansion of human CD3+ lymphocytes in major recipient organs. Similar viral treatment also prevents human-human mixed alloreactive T lymphocyte reactions in vitro. Our data suggest that ex vivo virotherapy with myxoma virus can be a simple and effective method for preventing GVHD following infusion of hematopoietic products containing alloreactive T lymphocytes such as: allogeneic hematopoietic stem and progenitor cells, donor leukocyte infusions and blood transfusions.

Endothelial cell derived angiocrine support of acute myeloid leukemia targeted by receptor tyrosine kinase inhibition

In acute myeloid leukemia (AML), refractory disease is a major challenge and the leukemia microenvironment may harbor refractory disease. Human AML cell lines KG-1 and HL-60 expressed receptors also found on endothelial cells (ECs) such as VEGFRs, PDGFRs, and cKit. When human AML cells were co-cultured with human umbilical vein endothelial cells (HUVECs) and primary bone marrow endothelial cell (BMECs), the AML cells were more resistant to cytarabine chemotherapy, even in transwell co-culture suggesting angiocrine regulation. Primary BMECs secreted significantly increased levels of VEGF-A and PDGF-AB after exposure to cytarabine. Pazopanib, a receptor tyrosine kinase inhibitor (RTKI) of VEGFRs, PDGFRs, and cKit, removed EC protection of AML cells and enhanced AML cell sensitivity to cytarabine. Xenograft modeling showed significant regression of AML cells and abrogation of BM hypervascularity in RTKI treated cohorts. Together, these results show direct cytotoxicity of RTKIs on AML cells and reversal of EC protection. Combining RTKIs with chemotherapy may serve as promising therapeutic strategy for patients with AML.

An injectable capillary-like microstructured alginate hydrogel improves left ventricular function after myocardial infarction in rats.

BACKGROUND A new post-myocardial infarction (MI) therapy is injection of high-water-content polymeric biomaterial gels (hydrogels) into damaged myocardium to modulate cardiac negative remodeling and preserve heart function. METHODS We investigated the therapeutic potential of a novel gelatinized alginate hydrogel with a unique microstructure of uniform capillary-like channels (termed Capgel). Shortly (48h) after induced anterior MI, Sprague Dawley rats received intramyocardial injection of Capgel directly into the antero-septal wall at the infarct border zone (n=12) or no injection (n=10, controls). Echocardiograms were performed at 48h (week 0) and 4weeks (week 4) to evaluate left ventricular function. RESULTS Echocardiograms showed 27% improvement of left ventricular systolic function over time with gel injection: fractional shortening increased from 26±3% at week 0 to 33±2% at week 4 (p=0.001). Capgel was present at the injection site after 4weeks, but was minimal at 8weeks. The remaining gel was heavily populated by CD68(+) macrophages with CD206(+) clusters and blood vessels. An in vitro experiment was performed to assess Angiotensin-(1-7) released from Capgel. Angiotensin-(1-7) was released from the Capgel in a sustained manner for 90days. CONCLUSIONS Use of Capgel, a degradable, bioactive hydrogel composed of gelatinized capillary-alginate gel, appears safe for intramyocardial injection, is associated with improved left ventricular function after MI in rats, and may provide a long-term supply of Angiotensin-(1-7).

Chemosensitizing AML cells by targeting bone marrow endothelial cells

Refractory disease is the greatest challenge in treating patients with acute myeloid leukemia (AML). Blood vessels may serve as sanctuary sites for AML. When AML cells were co-cultured with bone marrow endothelial cells (BMECs), a greater proportion of leukemia cells were in G0/G1. This led us to a strategy of targeting BMECs with tubulin-binding combretastatins, causing BMECs to lose their flat phenotype, degrade their cytoskeleton, cease growth, and impair migration despite unchanged BMEC viability and metabolism. Combretastatins also caused downregulation of BMEC adhesion molecules known to tether AML cells, including vascular cell adhesion molecule (VCAM)-1 and vascular endothelial (VE)-cadherin. When AML-BMEC co-cultures were treated with combretastatins, a significantly greater proportion of AML cells dislodged from BMECs and entered the G2/M cell cycle, suggesting enhanced susceptibility to cell cycle agents. Indeed, the combination of combretastatins and cytotoxic chemotherapy enhanced additive AML cell death. In vivo mice xenograft studies confirmed this finding by revealing complete AML regression after treatment with combretastatins and cytotoxic chemotherapy. Beyond highlighting the pathologic role of BMECs in the leukemia microenvironment as a protective reservoir of disease, these results support a new strategy for using vascular-targeting combretastatins in combination with cytotoxic chemotherapy to treat AML.

Ex vivo virotherapy with myxoma virus does not impair hematopoietic stem and progenitor cells

BACKGROUND Relapsing disease is a major challenge after hematopoietic cell transplantation for hematological malignancies. Myxoma virus (MYXV) is an oncolytic virus that can target and eliminate contaminating cancer cells from auto-transplant grafts. The aims of this study were to examine the impact of MYXV on normal hematopoietic stem and progenitor cells and define the optimal treatment conditions for ex vivo virotherapy. METHODS Bone marrow (BM) and mobilized peripheral blood stem cells (mPBSCs) from patients with hematologic malignancies were treated with MYXV at various time, temperature and incubation media conditions. Treated BM cells from healthy normal donors were evaluated using flow cytometry for MYXV infection, long-term culture-initiating cell (LTC-IC) assay and colony-forming cell (CFC) assay. RESULTS MYXV initiated infection in up to 45% of antigen-presenting monocytes, B cells and natural killer cells; however, these infections were uniformly aborted in >95% of all cells. Fresh graft sources showed higher levels of MYXV infection initiation than cryopreserved specimens, but in all cases less than 10% of CD34(+) cells could be infected after ex vivo MYXV treatment. MYXV did not impair LTC-IC colony numbers compared with mock treatment. CFC colony types and numbers were also not impaired by MYXV treatment. MYXV incubation time, temperature or culture media did not significantly change the percentage of infected cells, LTC-IC colony formation or CFC colony formation. CONCLUSIONS Human hematopoietic cells are non-permissive for MYXV. Human hematopoietic stem and progenitor cells were not infected and thus unaffected by MYXV ex vivo treatment.

Peripheral Blood Cytokine Levels After Acute Myocardial Infarction: IL-1β and IL-6 Related Impairment of Bone Marrow Function

Rationale: Intracoronary infusion of bone marrow (BM) mononuclear cells after acute myocardial infarction (AMI) has led to limited improvement in left ventricular function. Although experimental AMI models have implicated cytokine-related impairment of progenitor cell function, this response has not been investigated in humans. Objective: To test the hypothesis that peripheral blood (PB) cytokines predict BM endothelial progenitor cell colony outgrowth and cardiac function after AMI. Methods and Results: BM and PB samples were collected from 87 participants 14 to 21 days after AMI and BM from healthy donors was used as a reference. Correlations between cytokine concentrations and cell phenotypes, cell functions, and post-AMI cardiac function were determined. PB interleukin-6 (IL-6) negatively correlated with endothelial colony–forming cell colony maximum in the BM of patients with AMI (estimate±SE, −0.13±0.05; P=0.007). BM from healthy individuals showed a dose-dependent decrease in endothelial colony–forming cell colony outgrowth in the presence of exogenous IL-1&bgr; or IL-6 (P<0.05). Blocking the IL-1R or IL-6R reversed cytokine impairment. In AMI study participants, the angiogenic cytokine platelet-derived growth factor BB glycoprotein correlated positively with BM-derived colony-forming unit-endothelial colony maximum (estimate±SE, 0.01±0.002; P<0.001), multipotent mesenchymal stromal cell colony maximum (estimate±SE, 0.01±0.002; P=0.002) in BM, and mesenchymal stromal cell colony maximum in PB (estimate±SE, 0.02±0.005; P<0.001). Conclusions: Two weeks after AMI, increased PB platelet-derived growth factor BB glycoprotein was associated with increased BM function, whereas increased IL-6 was associated with BM impairment. Validation studies confirmed inflammatory cytokine impairment of BM that could be reversed by blocking IL-1R or IL-6R. Together, these studies suggest that blocking IL-1 or IL-6 receptors may improve the regenerative capacity of BM cells after AMI. Clinical Trial Registrations: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684060.