Jenna M. Rosano

Targeting VEGF-encapsulated immunoliposomes to MI heart improves vascularity and cardiac function

Recent attempts at rebuilding the myocardium using stem cells have yielded disappointing results. The lack of a supporting vasculature may, in part, explain these disappointing findings. However, concerns over possible side effects have hampered attempts at revascularizing the infarcted myocardium using systemic delivery of proangiogenic compounds. In this study, we develop the technology to enhance the morphology and function of postinfarct neovasculature. Previously, we have shown that the up‐regulated expression of endothelial cell adhesion molecules in the myocardial infarction (MI) region provides a potential avenue for selectively targeting drugs to infarcted tissue. After treatment with anti‐P‐selectin‐conjugated liposomes containing vascular endothelial growth factor (VEGF), changes in cardiac function and vasculature post‐MI were quantified in a rat MI model. Targeted delivery of VEGF to post‐MI tissue resulted in significant increase in fractional shortening and improved systolic function. These functional improvements were accompanied by a 21% increase in the number of anatomical vessels and a 74% increase in the number of perfused vessels in the MI region of treated animals. No significant improvements in cardiac function were observed in untreated, systemic VEGF‐treated, nontargeted liposome‐treated, or blank immunoliposome‐treated animals. Targeted delivery of low doses of proangiogenic compounds to post‐MI tissue results in significant improvements in cardiac function and vascular structure.—Scott, R. C., Rosano, J. M., Ivanov, Z., Wang, B., Lee‐Gau Chong, P., Issekutz, I. C., Crabbe, D. L., Kiani, M. F. Targeting VEGF‐encapsulated immunoliposomes to MI heart improves vascularity and cardiac function. FASEB J. 23, 3361–3367 (2009). www.fasebj.org

Towards a targeted multi-drug delivery approach to improve therapeutic efficacy in breast cancer

Importance of the field: Significant improvements in breast cancer treatments have resulted in a significant decrease in mortality. However, current breast cancer therapies, for example, chemotherapy, often result in high toxicity and nonspecific side effects. Other treatments, such as hormonal and antiangiogenic therapies, often have low treatment efficacy if used alone. In addition, acquired drug resistance decreases further the treatment efficacy of these therapies. Intra-tumor heterogeneity of the tumor tissue may be a major reason for the low treatment efficacy and the development of chemoresistance. Therefore, targeted multi-drug therapy is a valuable option for addressing the multiple mechanisms that may be responsible for reduced efficacy of current therapies. Areas covered in this review: In this article, different classes of drugs for treating breast cancer, the possible reasons for the drug resistance in breast cancer, as well as different targeted drug delivery systems are summarized. The current targeting strategies used in cancer treatment are discussed. What the reader will gain: This article considers the current state of breast cancer therapy and the possible future directions in targeted multi-drug delivery for treating breast cancer. Take home message: A better understanding of tumor biology and physiological responses to nanoparticles, as well as advanced nanoparticle design, are needed to improve the therapeutic outcomes for treating breast cancer using nanoparticle-based targeted drug delivery systems. Moreover, selective delivery of multi-drugs to tumor tissue using targeted drug delivery systems may reduce systemic toxicity further, overcome drug resistances, and improve therapeutic efficacy in treating breast cancer.

Fourier transform infrared spectroscopic imaging of cardiac tissue to detect collagen deposition after myocardial infarction.

Myocardial infarction often leads to an increase in deposition of fibrillar collagen. Detection and characterization of this cardiac fibrosis is of great interest to investigators and clinicians. Motivated by the significant limitations of conventional staining techniques to visualize collagen deposition in cardiac tissue sections, we have developed a Fourier transform infrared imaging spectroscopy (FT-IRIS) methodology for collagen assessment. The infrared absorbance band centered at 1338  cm(-1), which arises from collagen amino acid side chain vibrations, was used to map collagen deposition across heart tissue sections of a rat model of myocardial infarction, and was compared to conventional staining techniques. Comparison of the size of the collagen scar in heart tissue sections as measured with this methodology and that of trichrome staining showed a strong correlation (R=0.93). A Pearson correlation model between local intensity values in FT-IRIS and immuno-histochemical staining of collagen type I also showed a strong correlation (R=0.86). We demonstrate that FT-IRIS methodology can be utilized to visualize cardiac collagen deposition. In addition, given that vibrational spectroscopic data on proteins reflect molecular features, it also has the potential to provide additional information about the molecular structure of cardiac extracellular matrix proteins and their alterations.

Targeted Delivery of VEGF to Treat Myocardial Infarction

Noninvasive injection of pro-angiogenic compounds such as vascular endothelial growth factor (VEGF) has shown promising results in regenerating cardiac microvasculature. However, these results have failed to translate into successful clinical trials in part due to the short half-life of VEGF in circulation. Increasing the dose of VEGF may increase its availability to the target tissue, but harmful side-effects remain a concern. Encapsulating and selectively targeting VEGF to the MI border zone may circumvent these problems. Anti-P-selectin conjugated immunoliposomes containing VEGF were developed to target the infarct border zone in a rat MI model. Targeted VEGF therapy significantly improves vascularization and cardiac function after an infarction.

Identification of mesenchymal stem cell differentiation state using dual-micropore microfluidic impedance flow cytometry

As stem cell therapies become more common in the clinic, there is a greater need for real-time, label-free monitoring of the differentiation status of the cells. In this paper, we present a dual-micropore-based, high-throughput microfluidic electrical impedance flow cytometer for non-invasive identification of the differentiation state of mesenchymal stem cells. The mesenchymal stem cells were induced to differentiate into osteoblasts over a 21 day period. Samples of mesenchymal stem cells and osteoblasts were flowed through the device, and impedance measurements were acquired over a frequency range from 50 kHz to 10 MHz. The opacity and relative angle, which shed light on the membrane capacitance and interior dielectric properties of cells, were used as interrogation parameters to analyze collected impedance data. Specifically, identification of mesenchymal stem cells and osteoblasts in a mixed population was optimized using a combination of opacity signature at 500 kHz and relative angle at 3 MHz. Identification of both cell populations in a mixed sample was successfully achieved with an accuracy of 87%. The results show a progressive increase in the number of osteoblasts throughout the 21 day differentiation process, with 36% more mesenchymal stem cells differentiated after 14 days of induction compared to after just 7 days. The dual-micropore microfluidic impedance flow cytometer system may become an important non-invasive tool for assessing stem cell quality and differentiation stages for future regenerative medicine applications.

Label-free mesenchymal stem cell enrichment from bone marrow samples by inertial microfluidics

Isolation of pure populations of mesenchymal stem cells from bone marrow aspirate is a critical need in regenerative medicine such as orthopedic and cartilage reconstruction with important clinical and therapeutic implications. Currently available stem cell isolation systems mainly rely on intrusive immuno-labeling techniques. Mesenchymal stem cells in bone marrow samples are typically larger than other cells, which can be used as a distinctive biophysical cue for non-invasive isolation. In this work, a spiral-shaped inertial microfluidic sorter was developed to isolate mesenchymal stem cells from mouse bone marrow samples with minimal sample preparation steps. To characterize the sorting performance, cultured mesenchymal stem cells were spiked into tissue-digested mouse bone marrow cells. At a flow rate of 1.6 mL min−1, an average enrichment of 6.0× and a recovery of 73% were demonstrated. About 3 × 106 tissue-digested bone marrow cells can be processed in 1 minute with a single microfluidic run. The recovered mesenchymal stem cells after microfluidic sorting retained high (>95%) viability and similar immuno-phenotype expressions and multi-potencies in tri-differentiation lineages to unprocessed cells. This rapid, label-free and non-invasive inertial microfluidic sorter has practical applications in target stem cell enrichment in stem cell therapy.

TARGETED DELIVERY OF VASCULAR ENDOTHELIAL GROWTH FACTOR FAVORABLY ALTERS CARDIAC REMODELING AND FUNCTION AFTER A LARGE MYOCARDIAL INFARCTION

Abstract Category: Acute Myocardial Infarction--TherapyPresentation Number: 0921-07Authors: Jenna M. Rosano, Zhanna Ivanov, Robert C. Scott, Bin Wang, Parkson Lee-Gau Chong, Mohammad Kiani, Deborah Crabbe, Temple University, Philadelphia, PABackground: Targeted delivery of vascular endothelial growth factor (VEGF) to the infarct border zone could initiate the local growth of blood vessels and alter the remodeling process. Selective targeting of VEGF post-MI may attenuate adverse remodeling and improve cardiac function.Methods: Sprague-Dawley rats underwent coronary ligation to create a large MI. Animals received either a dose of 0.1 ml anti-P-selectin conjugated immunoliposomes containing VEGF (0.12 ug/kg, n=7) or empty immunoliposomes (EI, n=5). An untreated MI group was followed for comparison (UMI, n=6). Serial echocardiograms were acquired for 4 weeks to measure LV internal dimensions and function. Histochemical staining with DiOC7 was used to quantify the number of perfused vessels in the infarct region. Gomoris trichrome and picrosirius red were used to quantify collagen. Data presented are mean SEM.Results: VEGF treated hearts had a 74 % increase in the number of perfused vessels in post-MI border zone compared to UMI hearts. Vascular improvements were accompanied by an increase in the diastolic relative wall thickness in VEGF vs. UMI groups (0.37 0.03 vs. 0.27 0.02, p<0.008) indicating more favorable remodeling. Accompanying these changes was a shorter collagen scar (29.7 1.6% vs. 40.3 2.4%) and lower collagen volume fraction (54.8 4.2% vs. 91.8% 4.2%).Conclusions: Targeted delivery of a low dose of VEGF to the infarct border zone results in signiicant improvements in microvascular structure and LV remodeling.

Engineering Cardiac Tissue Using Stem Cell Therapy to Mend the Broken Heart

Myocardial infarction (MI) is one of the most severe forms of coronary artery disease and is the leading cause of death in the United States [1]. Current treatments for an MI are either highly invasive, such as coronary artery bypass grafting and stent angioplasty, or might have undesirable long-term effects as is the case with pharmacological interventions. However, newly emerging methodologies, such as a less invasive stem cell therapy, aim to cure the disease rather than just alleviate its symptoms. This new tissue engineering technology has shown promise in restoring the homeostasis of the heart muscle after MI in preclinical and clinical studies [2]. However, controversies regarding inconsistent methodologies and a lack of mechanistic understanding of its actions have hampered progress in this field [3].© 2009 ASME