Subcutaneous injection of adipose stromal cell-secretome improves renal function and reduces inflammation in established acute kidney injury

BACKGROUND

Adipose stromal cells (ASC) are a form of mesenchymal stromal cells that elicit effects primarily via secreted factors, which may have advantages for the treatment of injury or disease. Several previous studies have demonstrated a protective role for MSC/ASC on mitigating acute kidney injury but whether ASC derived factors could hasten recovery from established injury has not been evaluated.

METHODS

We generated a concentrated secretome (CS) of human ASC under well-defined conditions and evaluated its ability to improve the recovery of renal function in a preclinical model of acute kidney injury (AKI) in rats. 24 h following bilateral ischemia/reperfusion (I/R), rats were randomized following determination of plasma creatinine into groups receiving vehicle -control or ASC-CS treatment by subcutaneous injection (2 mg protein/kg) and monitored for evaluation of renal function, structure and inflammation.

RESULTS

Renal function, assessed by plasma creatinine levels, recovered faster in ASC-CS treated rats vs vehicle. The most prominent difference between the ASC-CS treated vs vehicle was observed in rats with the most severe degree of initial injury (Pcr > 3.0 mg/dl 24 h post I/R), whereas rats with less severe injury (Pcr < 2.9 mg/dl) recovered quickly regardless of treatment. The quicker recovery of ASC-treated rats with severe injury was associated with less tissue damage, inflammation, and lower plasma angiopoietin 2. In vitro, ASC-CS attenuated the activation of the Th17 phenotype in lymphocytes isolated from injured kidneys.

CONCLUSIONS

Taken together, these data suggest that ASC-CS represents a potent therapeutic option to improve established AKI.

Diminished vasculogenesis under inflammatory conditions is mediated by Activin A

Severe inflammatory stress often leads to vessel rarefaction and fibrosis, resulting in limited tissue recovery. However, signaling pathways mediating these processes are not completely understood. Patients with ischemic and inflammatory conditions have increased systemic Activin A level, which frequently correlates with the severity of pathology. Yet, Activin A's contribution to disease progression, specifically to vascular homeostasis and remodeling, is not well defined. This study investigated vasculogenesis in an inflammatory environment with an emphasis on Activin A's role. Exposure of endothelial cells (EC) and perivascular cells (adipose stromal cells, ASC) to inflammatory stimuli (represented by blood mononuclear cells from healthy donors activated with lipopolysaccharide, aPBMC) dramatically decreased EC tubulogenesis or caused vessel rarefaction compared to control co-cultures, concurrent with increased Activin A secretion. Both EC and ASC upregulated Inhibin Ba mRNA and Activin A secretion in response to aPBMC or their secretome. We identified TNFα (in EC) and IL-1β (in EC and ASC) as the exclusive inflammatory factors, present in aPBMC secretome, responsible for induction of Activin A. Similar to ASC, brain and placental pericytes upregulated Activin A in response to aPBMC and IL-1β, but not TNFα. Both these cytokines individually diminished EC tubulogenesis. Blocking Activin A with neutralizing IgG mitigated detrimental effects of aPBMC or TNFα/IL-1β on tubulogenesis in vitro and vessel formation in vivo. This study delineates the signaling pathway through which inflammatory cells have a detrimental effect on vessel formation and homeostasis, and highlights the central role of Activin A in this process. Transitory interference with Activin A during early phases of inflammatory or ischemic insult, with neutralizing antibodies or scavengers, may benefit vasculature preservation and overall tissue recovery.

Extracellular vesicles as personalized medicine

Extracellular vesicles (EVs) are released from all cells in the body, forming an important intercellular communication network that contributes to health and disease. The contents of EVs are cell source-specific, inducing distinct signaling responses in recipient cells. The specificity of EVs and their accumulation in fluid spaces that are accessible for liquid biopsies make them highly attractive as potential biomarkers and therapies for disease. The duality of EVs as favorable (therapeutic) or unfavorable (pathological) messengers is context dependent and remains to be fully determined in homeostasis and various disease states. This review describes the use of EVs as biomarkers, drug delivery vehicles, and regenerative therapeutics, highlighting examples involving viral infections, cancer, and neurological diseases. There is growing interest to provide personalized therapy based on individual patient and disease characteristics. Increasing evidence suggests that EV biomarkers and therapeutic approaches are ideal for personalized medicine due to the diversity and multifunctionality of EVs.

Development of a student-driven undergraduate program in regenerative medicine

As it begins to enter the clinic, regenerative medicine has the potential to revolutionize healthcare. Although there exists a growing need for individuals well-versed in the practice of regenerative medicine, few undergraduate institutions offer opportunities to learn about the topic. This article highlights the conception of two novel undergraduate courses in regenerative medicine developed through collaboration between students and faculty at our University to fill this void in the undergraduate curriculum. Lectures from scientists, healthcare professionals, regulatory experts and biotechnology leaders introduced students to regenerative medicine research and the translational process, and a certificate program incorporating relevant coursework and research experience is in development. This pipeline will guide promising undergraduate students to the field of regenerative medicine.

Human Heart Anoxia and Reperfusion Tissue (HEART) Model for the Rapid Study of Exosome Bound miRNA Expression As Biomarkers for Myocardial Infarction

Current biomarkers for myocardial infarction (MI) diagnosis are typically late markers released upon cell death, incapable of distinguishing between ischemic and reperfusion injury and can be symptoms of other pathologies. Circulating microRNAs (miRNAs) have recently been proposed as alternative biomarkers for MI diagnosis; however, detecting the changes in the human cardiac miRNA profile during MI is extremely difficult. Here, to study the changes in miRNA levels during acute MI, a heart-on-chip model with a cardiac channel, containing human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes in human heart decellularized matrix and collagen, and a vascular channel, containing hiPSC-derived endothelial cells, is developed. This model is exposed to anoxia followed by normoxia to mimic ischemia and reperfusion, respectively. Using a highly sensitive miRNA biosensor that the authors developed, the exact same increase in miR-1, miR-208b, and miR-499 levels in the MI-on-chip and the time-matched human blood plasma samples collected before and after ischemia and reperfusion, is shown. That the surface marker profile of exosomes in the engineered model changes in response to ischemic and reperfusion injury, which can be used as biomarkers to detect MI, is also shown. Hence, the MI-on-chip model developed here can be used in biomarker discovery.

Bone marrow- or adipose-mesenchymal stromal cell secretome preserves myocardial transcriptome profile and ameliorates cardiac damage following ex vivo cold storage

BACKGROUND

Heart transplantation, a life-saving approach for patients with end-stage heart disease, is limited by shortage of donor organs. While prolonged storage provides more organs, it increases the extent of ischemia. Therefore, we seek to understand molecular mechanisms underlying pathophysiological changes of donor hearts during prolonged storage. Additionally, considering mesenchymal stromal cell (MSC)-derived paracrine protection, we aim to test if MSC secretome preserves myocardial transcriptome profile and whether MSC secretome from a certain source provides the optimal protection in donor hearts during cold storage.

METHODS AND RESULTS

Isolated mouse hearts were divided into: no cold storage (control), 6 h cold storage (6 h-I), 6 h-I + conditioned media from bone marrow MSCs (BM-MSC CM), and 6 h-I + adipose-MSC CM (Ad-MSC CM). Deep RNA sequencing analysis revealed that compared to control, 6 h-I led to 266 differentially expressed genes, many of which were implicated in modulating mitochondrial performance, oxidative stress response, myocardial function, and apoptosis. BM-MSC CM and Ad-MSC CM restored these gene expression towards control. They also improved 6 h-I-induced myocardial functional depression, reduced inflammatory cytokine production, decreased apoptosis, and reduced myocardial H₂O₂. However, neither MSC-exosomes nor exosome-depleted CM recapitulated MSC CM-ameliorated apoptosis and CM-improved mitochondrial preservation during cold ischemia. Knockdown of Per2 by specific siRNA abolished MSC CM-mediated these protective effects in cardiomyocytes following 6 h cold storage.

CONCLUSIONS

Our results demonstrated that using MSC secretome (BM-MSCs and Ad-MSCs) during prolonged cold storage confers preservation of the normal transcriptional "fingerprint", and reduces donor heart damage. MSC-released soluble factors and exosomes may synergistically act for donor heart protection.

A multiplexed ion-exchange membrane-based miRNA (MIX·miR) detection platform for rapid diagnosis of myocardial infarction

Micro RNAs (miRNAs) have shown great potential as rapid and discriminating biomarkers for acute myocardial infarction (AMI) diagnosis. We have developed a multiplexed ion-exchange membrane-based miRNA (MIX·miR) preconcentration/sensing amplification-free platform for quantifying in parallel a panel of miRNAs, including miR-1, miR-208b, and miR-499, from the same plasma samples from: 1) reference subjects with no evident coronary artery disease (NCAD); 2) subjects with stable coronary artery disease (CAD); and 3) subjects experiencing ST-elevation myocardial infarction (STEMI) prior to (STEMI-pre) and following (STEMI-PCI) percutaneous coronary intervention. The picomolar limit of detection from raw plasma and 3-decade dynamic range of MIX·miR permits detection of the miRNA panel in untreated samples from disease patients and its precise standard curve, provided by large 0.1 to 1 V signals and eliminates individual sensor calibration. The use of molecular concentration feature reduces the assay time to less than 30 minutes and increases the detection sensitivity by bringing all targets close to the sensors. miR-1 was low for NCAD patients but more than one order of magnitude above the normal value for all samples from three categories (CAD, STEMI-pre, and STEMI-PCI) of patients with CAD. In fact, miR-1 expression levels of stable CAD, STEMI-pre and STEMI-PCI are each more than 10-fold higher than the previous class, in that order, well above the 95% confidence level of MIX·miR. Its overexpression estimate is significantly higher than the PCR benchmark. This suggests that, in contrast to protein biomarkers of myocardial injury, miR-1 appears to differentiate ischemia from both reperfusion injury and non-AMI CAD patients. The battery-operated MIX·miR can be a portable and low-cost AMI diagnostic device, particularly useful in settings where cardiac catheterization is not readily available to determine the status of coronary reperfusion.

Recommendations for Nomenclature and Definition Of Cell Products Intended for Human Cardiovascular Use

Exogenous cell-based therapy has emerged as a promising new strategy to facilitate repair of hearts damaged by acute or chronic injury. However, the field of cell-based therapy is handicapped by the lack of standardized definitions and terminology, making comparisons across studies challenging. Even the term "stem cell therapy" is misleading because only a small percentage of cells derived from adult bone marrow, peripheral blood, or adipose tissue meets the accepted hematopoietic or developmental definition of stem cells. Furthermore, cells (stem or otherwise) are dynamic biological products, meaning that their surface marker expression, phenotypic and functional characteristics, and the products they secrete in response to their microenvironment can change. It is also important to point out that most surface markers are seldom specific for a cell type. In this article, we discuss the lack of consistency in the descriptive terminology used in cell-based therapies and offer guidelines aimed at standardizing nomenclature and definitions to improve communication among investigators and the general public.

A Phase II study of autologous mesenchymal stromal cells and c-kit positive cardiac cells, alone or in combination, in patients with ischaemic heart failure: the CCTRN CONCERT-HF trial

AIMS

CONCERT-HF is an NHLBI-sponsored, double-blind, placebo-controlled, Phase II trial designed to determine whether treatment with autologous bone marrow-derived mesenchymal stromal cells (MSCs) and c-kit positive cardiac cells (CPCs), given alone or in combination, is feasible, safe, and beneficial in patients with heart failure (HF) caused by ischaemic cardiomyopathy.

METHODS AND RESULTS

Patients were randomized (1:1:1:1) to transendocardial injection of MSCs combined with CPCs, MSCs alone, CPCs alone, or placebo, and followed for 12 months. Seven centres enrolled 125 participants with left ventricular ejection fraction of 28.6 ± 6.1% and scar size 19.4 ± 5.8%, in New York Heart Association class II or III. The proportion of major adverse cardiac events (MACE) was significantly decreased by CPCs alone (-22% vs. placebo, P = 0.043). Quality of life (Minnesota Living with Heart Failure Questionnaire score) was significantly improved by MSCs alone (P = 0.050) and MSCs + CPCs (P = 0.023) vs. placebo. Left ventricular ejection fraction, left ventricular volumes, scar size, 6-min walking distance, and peak oxygen consumption did not differ significantly among groups.

CONCLUSIONS

This is the first multicentre trial assessing CPCs and a combination of two cell types from different tissues in HF patients. The results show that treatment is safe and feasible. Even with maximal guideline-directed therapy, both CPCs and MSCs were associated with improved clinical outcomes (MACE and quality of life, respectively) in ischaemic HF without affecting left ventricular function or structure, suggesting possible systemic or paracrine cellular mechanisms. Combining MSCs with CPCs was associated with improvement in both these outcomes. These results suggest potential important beneficial effects of CPCs and MSCs and support further investigation in HF patients.

Adipose stem cell secretome markedly improves rodent heart and human induced pluripotent stem cell-derived cardiomyocyte recovery from cardioplegic transport solution exposure

Heart transplantation is a life-saving therapy for end-stage organ failure. Organ deterioration during transportation limits storage to 4 hours, limiting hearts available. Approaches ameliorating organ damage could increase the number of hearts acceptable for transplantation. Prior studies show that adipose-derived stem/stromal cell secretome (ASC-S) rescues tissues from postischemic damage in vivo. This study tested whether ASC-S preserved the function of mouse hearts and human induced pluripotent stem cell-derived cardiomyocytes (iCM) exposed to organ transportation and transplantation conditions. Hearts were subjected to cold University of Wisconsin (UW) cardioplegic solution ± ASC-S for 6 hours followed by analysis using the Langendorff technique. In parallel, the effects of ASC-S on the recovery of iCM from UW solution were examined when provided either during or after cold cardioplegia. Exposure of hearts and iCM to UW deteriorated contractile activity and caused cell apoptosis, worsening in iCM as a function of exposure time; these were ameliorated by augmenting with ASC-S. Silencing of superoxide dismutase 3 and catalase expression prior to secretome generation compromised the ASC-S cardiomyocyte-protective effects. In this study, a novel in vitro iCM model was developed to complement a rodent heart model in assessing efficacy of approaches to improve cardiac preservation. ASC-S displays strong cardioprotective activity on iCM either with or following cold cardioplegia. This effect is associated with ASC-S-mediated cellular clearance of reactive oxygen species. The effect of ASC-S on the temporal recovery of iCM function supports the possibility of lengthening heart storage by augmenting cardioplegic transport solution with ASC-S, expanding the pool of hearts for transplantation.

Allogeneic Mesenchymal Cell Therapy in Anthracycline-Induced Cardiomyopathy Heart Failure Patients: The CCTRN SENECA Trial

BACKGROUND

Anthracycline-induced cardiomyopathy (AIC) may be irreversible with a poor prognosis, disproportionately affecting women and young adults. Administration of allogeneic bone marrow-derived mesenchymal stromal cells (allo-MSCs) is a promising approach to heart failure (HF) treatment.

OBJECTIVES

SENECA (Stem Cell Injection in Cancer Survivors) was a phase 1 study of allo-MSCs in AIC.

METHODS

Cancer survivors with chronic AIC (mean age 56.6 years; 68% women; NT-proBNP 1,426 pg/ml; 6 enrolled in an open-label, lead-in phase and 31 subjects randomized 1:1) received 1 × 10⁸ allo-MSCs or vehicle transendocardially. Primary objectives were safety and feasibility. Secondary efficacy measures included cardiac function and structure measured by cardiac magnetic resonance imaging (CMR), functional capacity, quality of life (Minnesota Living with Heart Failure Questionnaire), and biomarkers.

RESULTS

A total of 97% of subjects underwent successful study product injections; all allo-MSC-assigned subjects received the target dose of cells. Follow-up visits were well-attended (92%) with successful collection of endpoints in 94% at the 1-year visit. Although 58% of subjects had non-CMR compatible devices, CMR endpoints were successfully collected in 84% of subjects imaged at 1 year. No new tumors were reported. There were no significant differences between allo-MSC and vehicle groups with regard to clinical outcomes. Secondary measures included 6-min walk test (p = 0.056) and Minnesota Living with Heart Failure Questionnaire score (p = 0.048), which tended to favor the allo-MSC group.

CONCLUSIONS

In this first-in-human study of cell therapy in patients with AIC, transendocardial administration of allo-MSCs appears safe and feasible, and CMR was successfully performed in the majority of the HF patients with devices. This study lays the groundwork for phase 2 trials aimed at assessing efficacy of cell therapy in patients with AIC.

Distinct Factors Secreted by Adipose Stromal Cells Protect the Endothelium From Barrier Dysfunction and Apoptosis

We have shown previously that adipose stromal cell (ASC)-derived conditioned media (CM) limited lung injury, endothelial barrier dysfunction, and apoptosis. Here, we used endothelial hyperpermeability and apoptosis assays to investigate how concentration processes affect endothelium-directed bioactivity of ASC-CM and to gain information on the nature of bioactive factors. Comparison of ASC-CM concentrated with differential molecular weight (MW) cutoff filters showed that endothelial barrier protection depended on the species-specific factors in ASC-CM fractionated with MW > 50 kDa. Known barrier regulators-keratin growth factor (KGF), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF)-were detected in ASC-CM fraction of > 100 kDa. Pretreatment of endothelial monolayers with concentrations of KGF, VEGF, and HGF detected in ASC-CM showed that only KGF and HGF protect the endothelium from barrier dysfunction. Depletion of KGF and HGF from ASC-CM attenuated ASC-CM's ability to protect the endothelial barrier. In contrast to barrier-protective factors, apoptosis-protective factors fractionated with MW < 3 kDa and were not species-specific. Application of donors of apoptosis-mitigating gases showed that the CO donor carbon monoxide-releasing molecule 2 (CORM2) protected the endothelium from apoptosis, while the H₂S donor NaSH did not. Knockdown of CO-generating heme oxygenase 1 in ASC attenuated ASC-CM's ability to protect the endothelium from apoptosis. We have shown that tumor necrosis factor alpha (TNFα)-induced apoptosis in endothelium is c-Jun N-terminal kinase (JNK)-dependent, and JNK activation is inhibited by ASC-CM pretreatment of endothelial cells. ASC-CM from heme oxygenase 1-depleted ASC displayed attenuated ability to suppress endothelial JNK activation, suggesting that CO-mediated protection of the endothelium from apoptosis is achieved by the downregulation of the JNK pathway. Altogether, our results demonstrate that the concentration of ASC-CM with low MW cutoff filters significantly reduces its anti-apoptotic activity while preserving its barrier-protective activity.

Cardiac stem cell therapy among Clinics of Uncertain Regulatory Status (COURS): under-regulated, under-observed, incompletely understood

Background

Although a large body of information exists relating to cellular therapies, much of this information is either anecdotal or has been obtained from relatively small clinical trials, so that the level of evidence available to direct adoption of therapeutic approaches is quite limited. Despite this, a large number of clinics offer various cellular treatments without having gone through the processes of FDA approval. Florida is considered a “hotspot” of such sites, with a large number of clinics relative to the population.

Methods

To better understand the magnitude and scope of this issue with a specific focus on cardiovascular disease, we surveyed clinics in Florida advertising “cell therapy for heart failure”. We identified only 8 clinics that “treat cardiac conditions, including heart failure.” Data on administration route, cell type used, dose, success rate, cost, and training of persons performing procedures were collected when available, via email, telephone, or website information.

Results

A total of 20,135 patients were identified as treated: 2157 for cardiac conditions. All clinics reported administering cells intravenously, using either adipose- or umbilical-derived sources. Doses ranged from 30 to 150 million cells per treatment. The “success rate” ranged from 65 to 85%, with costs from $6000 to $20,700. Procedures were performed by PAs, MDs, and DOs.

Conclusion

Large numbers of patients (> 10% of all 20,135 patients) have been and presumably are still are being treated for “cardiac conditions.” We conclude that implementation of uniform data collection with an outcome registry, as well as creation of a public database listing FDA-approved cell-based clinical trials, would be useful to patients and the cardiovascular field at large.

Immune Dysregulation in HFpEF: A Target for Mesenchymal Stem/Stromal Cell Therapy

Over 26 million people worldwide suffer from heart failure, a disease associated with a 1 year mortality rate of 22%. Half of these patients present heart failure with preserved ejection fraction (HFpEF), for which there is no available therapy to improve prognosis. HFpEF is strongly associated with aging, inflammation, and comorbid burden, which are thought to play causal roles in disease development. Mesenchymal stromal/stem cells (MSCs) have potent immunomodulatory actions and promote tissue healing, thus representing an attractive therapeutic option in HFpEF. In this review, we summarize recent data suggesting that a two-hit model of immune dysregulation lies at the heart of the HFpEF. A first hit is represented by genetic mutations associated with clonal hematopoiesis of indeterminate potential (CHIP), which skew immune cells toward a pro-inflammatory phenotype, are associated with HFpEF development in animal models, and with immune dysregulation and risk of HF hospitalization in patients. A second hit is induced by cardiovascular risk factors, which cause subclinical cardiac dysfunction and production of danger signals. In mice, these attract proinflammatory macrophages, Th1 and Th17 cells into the myocardium, where they are required for the development of HFpEF. MSCs have been shown to reduce the pro-inflammatory activity of immune cell types involved in murine HFpEF in vitro, and to reduce myocardial fibrosis and improve diastolic function in vivo, thus they may efficiently target immune dysregulation in HFpEF and stop disease progression.

Therapeutic Use of Adipose-Derived Stromal Cells in a Murine Model of Acute Pancreatitis

BACKGROUND

No specific therapy exists for acute pancreatitis (AP), and current treatment remains entirely supportive. Adipose stem cells (ASCs) have significant immunomodulatory and regenerative activities. We hypothesized that systemic administration of ASCs would mitigate inflammation in AP.

METHODS

AP was induced in mice by 6 hourly intraperitoneal injections of cerulein. Twenty-four hours after AP induction, mice were randomized into four systemic treatment groups: sham group (no acute pancreatitis), vehicle, human ASCs, and human ASC-conditioned media. Mice were sacrificed at 48 h, and blood and organs were collected and analyzed. Pancreatic injury was quantified histologically using a published score (edema, inflammation, and necrosis). Pancreatic inflammation was also studied by immunohistochemistry and PCR.

RESULTS

When using IV infusion of Hoechst-labeled ASCs, ASCs were found to localize to inflamed tissues: lungs and pancreas. Mice treated with ASCs had less severe AP, as shown by a significantly decreased histopathology score (edema, inflammation, and necrosis) (p = 0.001). ASCs infusion polarized pancreatic macrophages toward an anti-inflammatory M2 phenotype. ASC-conditioned media reduced pancreatic inflammation similarly to ASCs only, highlighting the importance of ASCs secreted factors in modulating inflammation.

CONCLUSION

Intravenous delivery of human ASCs markedly reduces pancreatic inflammation in a murine model of AP ASCs which represent an effective therapy for AP.

Adipose-derived stem cell conditioned medium impacts asymptomatic peripheral neuromuscular denervation in the mutant superoxide dismutase (G93A) transgenic mouse model of amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is devastating, leading to paralysis and death. Disease onset begins pre-symptomatically through spinal motor neuron (MN) axon die-back from musculature at ∼47 days of age in the mutant superoxide dismutase 1 (mSOD1G93A) transgenic ALS mouse model. This period may be optimal to assess potential therapies. We previously demonstrated that post-symptomatic adipose-derived stem cell conditioned medium (ASC-CM) treatment is neuroprotective in mSOD1G93A mice. We hypothesized that early disease onset treatment could ameliorate neuromuscular junction (NMJ) disruption.

OBJECTIVE

To determine whether pre-symptom administration of ASC-CM prevents early NMJ disconnection.

METHODS

We confirmed the NMJ denervation time course in mSOD1G93A mice using co-labeling of neurofilament and post-synaptic acetylcholine receptors (AchR) by α-bungarotoxin. We determined whether ASC-CM ameliorates early NMJ loss in mSOD1G93A mice by systemically administering 200μl ASC-CM or vehicle medium daily from post-natal days 35 to 47 and quantifying intact NMJs through co-labeling of neurofilament and synaptophysin with α-bungarotoxin in gastrocnemius muscle.

RESULTS

Intact NMJs were significantly decreased in 47 day old mSOD1G93A mice (p < 0.05), and daily systemic ASC-CM prevented disease-induced NMJ denervation compared to vehicle treated mice (p < 0.05).

CONCLUSIONS

Our results lay the foundation for testing the long-term neurological benefits of systemic ASC-CM therapy in the mSOD1G93A mouse model of ALS.

EMAPII Monoclonal Antibody Ameliorates Influenza A Virus-Induced Lung Injury

Influenza A virus (IAV) remains a major worldwide health threat, especially to high-risk populations, including the young and elderly. There is an unmet clinical need for therapy that will protect the lungs from damage caused by lower respiratory infection. Here, we analyzed the role of EMAPII, a stress- and virus-induced pro-inflammatory and pro-apoptotic factor, in IAV-induced lung injury. First, we demonstrated that IAV induces EMAPII surface translocation, release, and apoptosis in cultured endothelial and epithelial cells. Next, we showed that IAV induces EMAPII surface translocation and release to bronchoalveolar lavage fluid (BALF) in mouse lungs, concomitant with increases in caspase 3 activity. Injection of monoclonal antibody (mAb) against EMAPII attenuated IAV-induced EMAPII levels, weight loss, reduction of blood oxygenation, lung edema, and increase of the pro-inflammatory cytokine TNF alpha. In accordance with the pro-apoptotic properties of EMAPII, levels of caspase 3 activity in BALF were also decreased by mAb treatment. Moreover, we detected EMAPII mAb-induced increase in lung levels of M2-like macrophage markers YM1 and CD206. All together, these data strongly suggest that EMAPII mAb ameliorates IAV-induced lung injury by limiting lung cell apoptosis and shifting the host inflammatory setting toward resolution of inflammation.

Rationale and Design of the SENECA (StEm cell iNjECtion in cAncer survivors) Trial

OBJECTIVES

SENECA (StEm cell iNjECtion in cAncer survivors) is a phase I, randomized, double-blind, placebo-controlled study to evaluate the safety and feasibility of delivering allogeneic mesenchymal stromal cells (allo-MSCs) transendocardially in subjects with anthracycline-induced cardiomyopathy (AIC).

BACKGROUND

AIC is an incurable and often fatal syndrome, with a prognosis worse than that of ischemic or nonischemic cardiomyopathy. Recently, cell therapy with MSCs has emerged as a promising new approach to repair damaged myocardium.

METHODS

The study population is 36 cancer survivors with a diagnosis of AIC, left ventricular (LV) ejection fraction ≤40%, and symptoms of heart failure (NYHA class II-III) on optimally-tolerated medical therapy. Subjects must be clinically free of cancer for at least two years with a ≤ 30% estimated five-year risk of recurrence. The first six subjects participated in an open-label, lead-in phase and received 100 million allo-MSCs; the remaining 30 will be randomized 1:1 to receive allo-MSCs or vehicle via 20 transendocardial injections. Efficacy measures (obtained at baseline, 6 months, and 12 months) include MRI evaluation of LV function, LV volumes, fibrosis, and scar burden; assessment of exercise tolerance (six-minute walk test) and quality of life (Minnesota Living with Heart Failure Questionnaire); clinical outcomes (MACE and cumulative days alive and out of hospital); and biomarkers of heart failure (NT-proBNP).

CONCLUSIONS

This is the first clinical trial using direct cardiac injection of cells for the treatment of AIC. If administration of allo-MSCs is found feasible and safe, SENECA will pave the way for larger phase II/III studies with therapeutic efficacy as the primary outcome.

AMD3100 ameliorates cigarette smoke-induced emphysema-like manifestations in mice

We have shown that cigarette smoke (CS)-induced pulmonary emphysema-like manifestations are preceded by marked suppression of the number and function of bone marrow hematopoietic progenitor cells (HPCs). To investigate whether a limited availability of HPCs may contribute to CS-induced lung injury, we used a Food and Drug Administration-approved antagonist of the interactions of stromal cell-derived factor 1 (SDF-1) with its chemokine receptor CXCR4 to promote intermittent HPC mobilization and tested its ability to limit emphysema-like injury following chronic CS. We administered AMD3100 (5mg/kg) to mice during a chronic CS exposure protocol of up to 24 wk. AMD3100 treatment did not affect either lung SDF-1 levels, which were reduced by CS, or lung inflammatory cell counts. However, AMD3100 markedly improved CS-induced bone marrow HPC suppression and significantly ameliorated emphysema-like end points, such as alveolar airspace size, lung volumes, and lung static compliance. These results suggest that antagonism of SDF-1 binding to CXCR4 is associated with protection of both bone marrow and lungs during chronic CS exposure, thus encouraging future studies of potential therapeutic benefit of AMD3100 in emphysema.

Rationale and Design of the CONCERT-HF Trial (Combination of Mesenchymal and c-kit+ Cardiac Stem Cells As Regenerative Therapy for Heart Failure)

RATIONALE

Autologous bone marrow mesenchymal stem cells (MSCs) and c-kit⁺ cardiac progenitor cells (CPCs) are 2 promising cell types being evaluated for patients with heart failure (HF) secondary to ischemic cardiomyopathy. No information is available in humans about the relative efficacy of MSCs and CPCs and whether their combination is more efficacious than either cell type alone.

OBJECTIVE

CONCERT-HF (Combination of Mesenchymal and c-kit⁺ Cardiac Stem Cells As Regenerative Therapy for Heart Failure) is a phase II trial aimed at elucidating these issues by assessing the feasibility, safety, and efficacy of transendocardial administration of autologous MSCs and CPCs, alone and in combination, in patients with HF caused by chronic ischemic cardiomyopathy (coronary artery disease and old myocardial infarction).

METHODS AND RESULTS

Using a randomized, double-blinded, placebo-controlled, multicenter, multitreatment, and adaptive design, CONCERT-HF examines whether administration of MSCs alone, CPCs alone, or MSCs+CPCs in this population alleviates left ventricular remodeling and dysfunction, reduces scar size, improves quality of life, or augments functional capacity. The 4-arm design enables comparisons of MSCs alone with CPCs alone and with their combination. CONCERT-HF consists of 162 patients, 18 in a safety lead-in phase (stage 1) and 144 in the main trial (stage 2). Stage 1 is complete, and stage 2 is currently randomizing patients from 7 centers across the United States.

CONCLUSIONS

CONCERT-HF will provide important insights into the potential therapeutic utility of MSCs and CPCs, given alone and in combination, for patients with HF secondary to ischemic cardiomyopathy.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02501811.

Cigarette Smoking Impairs Adipose Stromal Cell Vasculogenic Activity and Abrogates Potency to Ameliorate Ischemia

Cigarette smoking (CS) adversely affects the physiologic function of endothelial progenitor, hematopoietic stem and progenitor cells. However, the effect of CS on the ability of adipose stem/stromal cells (ASC) to promote vasculogenesis and rescue perfusion in the context of ischemia is unknown. To evaluate this, ASC from nonsmokers (nCS-ASC) and smokers (CS-ASC), and their activity to promote perfusion in hindlimb ischemia models, as well as endothelial cell (EC) survival and vascular morphogenesis in vitro were assessed. While nCS-ASC improved perfusion in ischemic limbs, CS-ASC completely lost this therapeutic effect. In vitro vasculogenesis assays revealed that human CS-ASC and ASC from CS-exposed mice showed compromised support of EC morphogenesis into vascular tubes, and the CS-ASC secretome was less potent in supporting EC survival/proliferation. Comparative secretome analysis revealed that CS-ASC produced lower amounts of hepatocyte growth factor (HGF) and stromal cell-derived growth factor 1 (SDF-1). Conversely, CS-ASC secreted the angiostatic/pro-inflammatory factor Activin A, which was not detected in nCS-ASC conditioned media (CM). Furthermore, higher Activin A levels were measured in EC/CS-ASC cocultures than in EC/nCS-ASC cocultures. CS-ASC also responded to inflammatory cytokines with 5.2-fold increase in Activin A secretion, whereas nCS-ASC showed minimal Activin A induction. Supplementation of EC/CS-ASC cocultures with nCS-ASC CM or with recombinant vascular endothelial growth factor, HGF, or SDF-1 did not rescue vasculogenesis, whereas inhibition of Activin A expression or activity improved network formation up to the level found in EC/nCS-ASC cocultures. In conclusion, ASC of CS individuals manifest compromised in vitro vasculogenic activity as well as in vivo therapeutic activity. Stem Cells 2018;36:856-867.

Hypertension in pregnancy: Taking cues from pathophysiology for clinical practice

Pregnancy-related hypertension (PHTN) syndromes are a frequent and potentially deadly complication of pregnancy, while also negatively impacting the lifelong health of the mother and child. PHTN appears in women likely to develop hypertension later in life, with the stress of pregnancy unmasking a subclinical hypertensive phenotype. However, distinguishing between PHTN and chronic hypertension is essential for optimal management. Preeclampsia (PE) is linked to potentially severe outcomes and lacks effective treatments due to poorly understood mechanisms. Inadequate remodeling of spiral uterine arteries (SUAs), the cornerstone of PE pathophysiology, leads to hypoperfusion of the developing placenta. In normal pregnancies, extravillous trophoblast (EVT) cells assume an invasive phenotype and invade SUAs, transforming them into large conduits. Decidual natural killer cells play an essential role, mediating materno-fetal immune tolerance, inducing early SUA remodeling and regulating EVT invasiveness. Notch signaling is important in EVT phenotypic switch and is dysregulated in PE. The hypoxic placenta releases antiangiogenic and proinflammatory factors that converge upon maternal endothelium, inducing endothelial dysfunction, hypertension, and organ damage. Hypoxia-inducible factor 1-α is upstream of such molecules, whereas endothelin-1 is a major effector. We also describe important genetic links and evidence of incomplete materno-fetal immune tolerance, with PE patients presenting with autoantibodies, lower Treg , and higher Th 17 cells. Thus, PE manifestations arise as a consequence of mal-placentation or/and because of a predisposition of the maternal vascular bed to excessively react to pathogenic molecules. From this pathophysiological basis, we provide current and propose future therapeutic directions for PE.

GDNF secreted from adipose-derived stem cells stimulates VEGF-independent angiogenesis

Adipose tissue stroma contains a population of mesenchymal stem cells (MSC) promote new blood vessel formation and stabilization. These adipose-derived stem cells (ASC) promote de novo formation of vascular structures in vitro. We investigated the angiogenic factors secreted by ASC and discovered that glial-derived neurotrophic factor (GDNF) is a key mediator for endothelial cell network formation. It was found that both GDNF alone or present in ASC-conditioned medium (ASC-CM) stimulated capillary network formation by using human umbilical vein endothelial cells (HUVECs) and such an effect was totally independent of vascular endothelial growth factor (VEGF) activity. Additionally, we showed stimulation of capillary network formation by GDNF, but not VEGF, could be blocked by the Ret (rearranged during transfection) receptor antagonist RPI-1, a GDNF signaling inhibitor. Furthermore, GDNF were found to be overexpressed in cancer cells that were resistant to the anti-angiogenic treatment using the VEGF antibody. Cancer cells in the liver hepatocellular carcinoma (HCC), a non-nervous related cancer, highly overexpressed GDNF as compared to normal liver cells. Our data strongly suggest that, in addition to VEGF, GDNF secreted by ASC and HCC cells, may be another important factor promoting pathological neovascularization. Thus, GDNF may be a potential therapeutic target for HCC and obesity treatments.

Oncostatin M and TNF-α Induce Alpha-1 Antitrypsin Production in Undifferentiated Adipose Stromal Cells

Alpha-1 antitrypsin (A1AT), a circulating acute-phase reactant antiprotease, is produced and secreted by cells of endodermal epithelial origin, primarily hepatocytes, and by immune cells. Deficiency of A1AT is associated with increased risk of excessive lung inflammation and injury, especially following chronic cigarette smoke (CS) exposure. Exogenous administration of mesenchymal progenitor cells, including adipose tissue-derived stromal/stem cells (ASC), alleviates CS-induced lung injury through paracrine effectors such as growth factors. It is unknown, however, if mesodermal ASC can secrete functional A1AT and if CS exposure affects their A1AT production. Human ASC collected via liposuction from nonsmoking or smoking donors were stimulated by inflammatory cytokines tumor necrosis alpha (TNFα), oncostatin M (OSM), and/or dexamethasone (DEX) or were exposed to sublethal concentrations of ambient air control or CS extract (0.5%-2%). We detected minimal expression and secretion of A1AT by cultured ASC during unstimulated conditions, which significantly increased following stimulation with TNFα or OSM. Furthermore, TNFα and OSM synergistically enhanced A1AT expression and secretion, which were further increased by DEX. The A1AT transcript variant produced by stimulated ASC resembled that produced by bronchial epithelial cells rather than the variant produced by monocytes/macrophages. While the cigarette smoking status of the ASC donor had no measurable effect on the ability of ASC to induce A1AT expression, active exposure to CS extract markedly reduced A1AT expression and secretion by cultured ASC, as well as human tracheobronchial epithelial cells. ASC-secreted A1AT covalently complexed with neutrophil elastase in control ASC, but not in cells transfected with A1AT siRNA. Undifferentiated ASC may require priming to secrete functional A1AT, a potent antiprotease that may be relevant to stem cell therapeutic effects.

Hypoxia-induced activin A diminishes endothelial cell vasculogenic activity

Acute ischaemia causes a significant loss of blood vessels leading to deterioration of organ function. Multiple ischaemic conditions are associated with up‐regulation of activin A, but its effect on endothelial cells (EC) in the context of hypoxia is understudied. This study evaluated the role of activin A in vasculogenesis in hypoxia. An in vitro vasculogenesis model, in which EC were cocultured with adipose stromal cells (ASC), was used. Incubation of cocultures at 0.5% oxygen led to decrease in EC survival and vessel density. Hypoxia up‐regulated inhibin B_A (monomer of activin A) mRNA by 4.5‐fold and activin A accumulation in EC‐conditioned media by 10‐fold, but down‐regulated activin A inhibitor follistatin by twofold. Inhibin B_A expression was also increased in human EC injected into ischaemic mouse muscles. Activin A secretion was positively modulated by hypoxia mimetics dimethyloxalylglycine and desferrioxamine. Silencing HIF1α or HIF2α expression decreased activin A secretion in EC exposed to hypoxia. Introduction of activin A to cocultures decreased EC number and vascular density by 40%; conversely, blockade of activin A expression in EC or its activity improved vasculogenesis in hypoxia. Activin A affected EC survival directly and by modulating ASC paracrine activity leading to diminished ability of the ASC secretome to support EC survival and vasculogenesis. In conclusion, hypoxia up‐regulates EC secretion of activin A, which, by affecting both EC and adjacent mesenchymal cells, creates a micro‐environment unfavourable for vasculogenesis. This finding suggests that blockade of activin A signalling in ischaemic tissue may improve preservation of the affected tissue.

Electroacupuncture Promotes Central Nervous System-Dependent Release of Mesenchymal Stem Cells

Electroacupuncture (EA) performed in rats and humans using limb acupuncture sites, LI-4 and LI-11, and GV-14 and GV-20 (humans) and Bai-hui (rats) increased functional connectivity between the anterior hypothalamus and the amygdala and mobilized mesenchymal stem cells (MSCs) into the systemic circulation. In human subjects, the source of the MSC was found to be primarily adipose tissue, whereas in rodents the tissue sources were considered more heterogeneous. Pharmacological disinhibition of rat hypothalamus enhanced sympathetic nervous system (SNS) activation and similarly resulted in a release of MSC into the circulation. EA-mediated SNS activation was further supported by browning of white adipose tissue in rats. EA treatment of rats undergoing partial rupture of the Achilles tendon resulted in reduced mechanical hyperalgesia, increased serum interleukin-10 levels and tendon remodeling, effects blocked in propranolol-treated rodents. To distinguish the afferent role of the peripheral nervous system, phosphoinositide-interacting regulator of transient receptor potential channels (Pirt)-GCaMP3 (genetically encoded calcium sensor) mice were treated with EA acupuncture points, ST-36 and LIV-3, and GV-14 and Bai-hui and resulted in a rapid activation of primary sensory neurons. EA activated sensory ganglia and SNS centers to mediate the release of MSC that can enhance tissue repair, increase anti-inflammatory cytokine production and provide pronounced analgesic relief. Stem Cells 2017;35:1303-1315.

Human adipose stromal cell therapy improves survival and reduces renal inflammation and capillary rarefaction in acute kidney injury

Damage to endothelial cells contributes to acute kidney injury (AKI) by causing impaired perfusion, while the permanent loss of the capillary network following AKI has been suggested to promote chronic kidney disease. Therefore, strategies to protect renal vasculature may impact both short‐term recovery and long‐term functional preservation post‐AKI. Human adipose stromal cells (hASCs) possess pro‐angiogenic and anti‐inflammatory properties and therefore have been tested as a therapeutic agent to treat ischaemic conditions. This study evaluated hASC potential to facilitate recovery from AKI with specific attention to capillary preservation and inflammation. Male Sprague Dawley rats were subjected to bilateral ischaemia/reperfusion and allowed to recover for either two or seven days. At the time of reperfusion, hASCs or vehicle was injected into the suprarenal abdominal aorta. hASC‐treated rats had significantly greater survival compared to vehicle‐treated rats (88.7% versus 69.3%). hASC treatment showed hastened recovery as demonstrated by lower creatinine levels at 48 hrs, while tubular damage was significantly reduced at 48 hrs. hASC treatment resulted in a significant decrease in total T cell and Th17 cell infiltration into injured kidneys at 2 days post‐AKI, but an increase in accumulation of regulatory T cells. By day 7, hASC‐treated rats showed significantly attenuated capillary rarefaction in the cortex (15% versus 5%) and outer medulla (36% versus 18%) compared to vehicle‐treated rats as well as reduced accumulation of interstitial alpha‐smooth muscle actin‐positive myofibroblasts. These results suggest for the first time that hASCs improve recovery from I/R‐induced injury by mechanisms that contribute to decrease in inflammation and preservation of peritubular capillaries.

Adipose Stem Cell Function Maintained with Age: An Intra-Subject Study of Long-Term Cryopreserved Cells

Background

The progressive decline in tissue mechanical strength that occurs with aging is hypothesized to be due to a loss of resident stem cell number and function. As such, there is concern regarding use of autologous adult stem cell therapy in older patients. To abrogate this, many patients elect to cryopreserve the adipose stromal-vascular fraction (SVF) of lipoaspirate, which contains resident adipose stem cells (ASC). However, it is not clear yet if there is any clinical benefit from banking cells at a younger age.

Objectives

We performed a comparative analysis of SVF composition and ASC function from cells obtained under GMP conditions from the same three patients with time gap of 7 to 12 years.

Methods

SVF, cryobanked under good manufacturing practice (GMP) conditions, was thawed and cell yield, viability, and cellular composition were assessed. In parallel, ASC proliferation and efficiency of tri-lineage differentiation were evaluated.

Results

The results showed no significant differences existed in cell yield and SVF subpopulation composition within the same patient between harvest procedures 7 to 12 years apart. Further, no change in proliferation rates of cultured ASCs was found, and expanded cells from all patients were capable of tri-lineage differentiation.

Conclusions

By harvesting fat from the same patient at two time points, we have shown that despite the natural human aging process, the prevalence and functional activity of ASCs in an adult mesenchymal stem cell, is highly preserved.

Level of Evidence

5.

Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN PACE Trial (Patients With Intermittent Claudication Injected With ALDH Bright Cells)

BACKGROUND

Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms.

METHODS

All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety.

RESULTS

A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P=0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P=0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P=0.047) in participants with completely occluded femoral arteries.

CONCLUSIONS

ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097.

Abstract 133: Effectiveness of a Stem Cell-derived Therapeutic Factor Concentrate in a Mouse Embolic Stroke Model

Background: Early clinical trials of cell-based therapies in stroke have been very encouraging; however, technical hurdles may prevent widespread adoption. The salutary effects appear to be through release of “trophic” factors and immunomodulators which affect host repair and protection responses. We are developing a novel stroke therapy which is a clinically compliant cell-free, therapeutic factor concentrate (TFC) derived from adipose stem cell conditioned medium (ASC-CM). We will present data from a murine embolic stroke model study to determine the potential for clinical translation of TFC.

Methods: Embolic stroke was induced in C57/Bl6 male mice (16 - 18 wks old) by delivering 9 - 10 mm clot into the middle cerebral artery (MCA) territory. Mice were randomly picked up for the intravenous treatments (either vehicle or 20/50/100 uL of TFC; N= 10/group) immediately after stroke. Neurological deficits were evaluated at 48 hrs post stroke, and mice were also tested for the somatosensory functions using adhesive tape removal test (ATT) at 72 hrs before the sacrifice for TTC-stained infarct analysis. Statistical significance was determined at P < 0.05.

Results: Our data demonstrate a clear dose dependent response, with the highest dose tested (100 uL; ~4 mg total protein/kg body weight) being the most effective in the embolic stroke model. While the low-dose (20 uL; 0.8 mg/kg) did not show an effect in any outcomes measured, the middle dose (50 uL, ~2 mg/kg) was effective but less so than the highest dose (100 uL). TFC at 100 uL significantly improved neurological outcomes on Bederson scale, and also somatosensory function as determined by ATT. There was also a trend toward improved survival after stroke in 100 uL TFC treated group. Most importantly, while the 50 uL dose reduced the infarction volume by ~20%, the effect was >50% reduction with 100 uL treatment. TFC at any dose did not show any adverse effects such as the hemorrhagic transformation.

Conclusion: TFC is a potential therapy to improve post-stroke outcomes. We are repeating these studies with ovariectomized female mice and extending the studies to 1 month. Future studies with this model will test TFC (1) in combination with IV-tPA, (2) with delayed delivery (up to 24 hours post-stroke), (3) and in aged animals.

Human Adipose-Derived Stem Cells Suppress Elastase-Induced Murine Abdominal Aortic Inflammation and Aneurysm Expansion Through Paracrine Factors

Abdominal aortic aneurysm (AAA) is a potentially lethal disease associated with immune activation-induced aortic degradation. We hypothesized that xenotransplantation of human adipose-derived stem cells (hADSCs) would reduce aortic inflammation and attenuate expansion in a murine AAA model. Modulatory effects of ADSCs on immune cell subtypes associated with AAA progression were investigated using human peripheral blood mononuclear cells (hPBMNCs) cocultured with ADSCs. Murine AAA was induced through elastase application to the abdominal aorta in C57BL/6 mice. ADSCs were administered intravenously, and aortic changes were determined by ultrasonography and videomicrometry. Circulating monocytes, aortic neutrophils, CD28- T cells, FoxP3+ regulatory T cells (Tregs), and CD206+ M2 macrophages were assessed at multiple terminal time points. In vitro, ADSCs induced M2 macrophage and Treg phenotypes while inhibiting neutrophil transmigration and lymphocyte activation without cellular contact. Intravenous ADSC delivery reduced aneurysmal expansion starting from day 4 [from baseline: 54.8% (saline) vs. 16.9% (ADSCs), n = 10 at baseline, n = 4 at day 4, p < 0.001], and the therapeutic effect persists through day 14 (from baseline: 64.1% saline vs. 24.6% ADSCs, n = 4, p < 0.01). ADSC administration increased aortic Tregs by 20-fold (n = 5, p < 0.01), while decreasing CD4+CD28- (-28%), CD8+CD28- T cells (-61%), and Ly6G/C+ neutrophils (-43%, n = 5, p < 0.05). Circulating CD115+CXCR1-LY6C+-activated monocytes decreased in the ADSC-treated group by day 7 (-60%, n = 10, p < 0.05), paralleled by an increase in aortic CD206+ M2 macrophages by 2.4-fold (n = 5, p < 0.05). Intravenously injected ADSCs transiently engrafted in the lung on day 1 without aortic engraftment at any time point. In conclusion, ADSCs exhibit pleiotropic immunomodulatory effects in vitro as well as in vivo during the development of AAA. The temporal evolution of these effects systemically as well as in aortic tissue suggests that ADSCs induce a sequence of anti-inflammatory cellular events mediated by paracrine factors, which leads to amelioration of AAA progression.

Pulmonary Retention of Adipose Stromal Cells Following Intravenous Delivery Is Markedly Altered in the Presence of ARDS

Transplantation of mesenchymal stromal cells (MSCs) has been shown to effectively prevent lung injury in several preclinical models of acute respiratory distress syndrome (ARDS). Since MSC therapy is tested in clinical trials for ARDS, there is an increased need to define the dynamics of cell trafficking and organ-specific accumulation. We examined how the presence of ARDS changes retention and organ-specific distribution of intravenously delivered MSCs isolated from subcutaneous adipose tissue [adipose-derived stem cells (ADSCs)]. This type of cell therapy was previously shown to ameliorate ARDS pathology. ARDS was triggered by lipopolysaccharide (LPS) aspiration, 4 h after which 300,000 murine CRE⁺ ADSCs were delivered intravenously. The distribution of ADSCs in the lungs and other organs was assessed by real-time polymerase chain reaction (PCR) of genomic DNA. As anticipated, the majority of delivered ADSCs accumulated in the lungs of both control and LPS-challenged mice, with minor amounts distributed to the liver, kidney, spleen, heart, and brain. Interestingly, within 2 h following ADSC administration, LPS-challenged lungs retained significantly lower levels of ADSCs compared to control lungs (∼7% vs. 15% of the original dose, respectively), whereas the liver, kidney, spleen, and brain of ARDS-affected animals retained significantly higher numbers of ADSCs compared to control animals. In contrast, 48 h later, only LPS-challenged lungs continued to retain ADSCs (∼3% of the original dose), whereas the lungs of control animals and nonpulmonary organs in either control or ARDS mice had no detectable levels of ADSCs. Our data suggest that the pulmonary microenvironment during ARDS may lessen the pulmonary capillary occlusion by MSCs immediately following cell delivery while facilitating pulmonary retention of the cells.

Therapeutic Potential of Adipose-Derived Therapeutic Factor Concentrate for Treating Critical Limb Ischemia

Transplantation of adipose-derived stem cells (ADSCs) is an emerging therapeutic option for addressing intractable diseases such as critical limb ischemia (CLI). Evidence suggests that therapeutic effects of ADSCs are primarily mediated through paracrine mechanisms rather than transdifferentiation. These secreted factors can be captured in conditioned medium (CM) and concentrated to prepare a therapeutic factor concentrate (TFC) composed of a cocktail of beneficial growth factors and cytokines that individually and in combination demonstrate disease-modifying effects. The ability of a TFC to promote reperfusion in a rabbit model of CLI was evaluated. A total of 27 adult female rabbits underwent surgery to induce ischemia in the left hindlimb. An additional five rabbits served as sham controls. One week after surgery, the ischemic limbs received intramuscular injections of either (1) placebo (control medium), (2) a low dose of TFC, or (3) a high dose of TFC. Limb perfusion was serially assessed with a Doppler probe. Blood samples were analyzed for growth factors and cytokines. Tissue was harvested postmortem on day 35 and assessed for capillary density by immunohistochemistry. At 1 month after treatment, tissue perfusion in ischemic limbs treated with a high dose of TFC was almost double (p < 0.05) that of the placebo group [58.8 ± 23 relative perfusion units (RPU) vs. 30.7 ± 13.6 RPU; mean ± SD]. This effect was correlated with greater capillary density in the affected tissues and with transiently higher serum levels of the angiogenic and prosurvival factors vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). The conclusions from this study are that a single bolus administration of TFC demonstrated robust effects for promoting tissue reperfusion in a rabbit model of CLI and that a possible mechanism of revascularization was promotion of angiogenesis by TFC. Results of this study demonstrate that TFC represents a potent therapeutic cocktail for patients with CLI, many of whom are at risk for amputation of the affected limb.

Human adipose-derived stem cells ameliorate cigarette smoke-induced murine myelosuppression via secretion of TSG-6

OBJECTIVE

Bone marrow-derived hematopoietic stem and progenitor cells (HSC/HPC) are critical to homeostasis and tissue repair. The aims of this study were to delineate the myelotoxicity of cigarette smoking (CS) in a murine model, to explore human adipose-derived stem cells (hASC) as a novel approach to mitigate this toxicity, and to identify key mediating factors for ASC activities.

METHODS

C57BL/6 mice were exposed to CS with or without i.v. injection of regular or siRNA-transfected hASC. For in vitro experiments, cigarette smoke extract was used to mimic the toxicity of CS exposure. Analysis of bone marrow HPC was performed both by flow cytometry and colony-forming unit assays.

RESULTS

In this study, we demonstrate that as few as 3 days of CS exposure results in marked cycling arrest and diminished clonogenic capacity of HPC, followed by depletion of phenotypically defined HSC/HPC. Intravenous injection of hASC substantially ameliorated both acute and chronic CS-induced myelosuppression. This effect was specifically dependent on the anti-inflammatory factor TSG-6, which is induced from xenografted hASC, primarily located in the lung and capable of responding to host inflammatory signals. Gene expression analysis within bone marrow HSC/HPC revealed several specific signaling molecules altered by CS and normalized by hASC.

CONCLUSION

Our results suggest that systemic administration of hASC or TSG-6 may be novel approaches to reverse CS-induced myelosuppression.

Adipose Stromal Cell Contact with Endothelial Cells Results in Loss of Complementary Vasculogenic Activity Mediated by Induction of Activin A

Adipose stem/stromal cells (ASCs) after isolation produce numerous angiogenic growth factors. This justifies their use to promote angiogenesis per transplantation. In parallel, local coimplantation of ASC with endothelial cells (ECs) leading to formation of functional vessels by the donor cells suggests the existence of a mechanism responsible for fine-tuning ASC paracrine activity essential for vasculogenesis. As expected, conditioned media (CM) from ASC promoted ECs survival, proliferation, migration, and vasculogenesis. In contrast, media from EC-ASC cocultures had neutral effects upon EC responses. Media from cocultures exhibited lower levels of vascular endothelial growth factor (VEGF), hepatic growth factor, angiopoietin-1, and stromal cell-derived factor-1 compared with those in ASC CM. Activin A was induced in ASC in response to EC exposure and was responsible for overall antivasculogenic activity of EC-ASC CM. Except for VEGF, activin A diminished secretion of all tested factors by ASC. Activin A mediated induction of VEGF expression in ASC, but also upregulated expression of VEGF scavenger receptor FLT-1 in EC in EC-ASC cocultures. Blocking the FLT-1 expression in EC led to an increase in VEGF concentration in CM. In vitro pre-exposure of ASC to low number of EC before subcutaneous coimplantation with EC resulted in decrease in vessel density in the implants. In vitro tests suggested that activin A was partially responsible for this diminished ASC activity. This study shows that neovessel formation is associated with induction of activin A expression in ASC; this factor, by affecting the bioactivity of both ASC and EC, directs the crosstalk between these complementary cell types to establish stable vessels.

Abstract 247: Adipose-derived Stem Cells Suppress Aortic Inflammation and Aneurysm Expansion through Paracrine Mediated Mechanisms in an Elastase-induced Murine Model

Introduction: Abdominal aortic aneurysm (AAA) formation is characterized by activation of innate and adaptive immune responses that initiate aortic wall degradation. We hypothesize that human adipose stromal cells (ASC) favorably modulate these immune responses through paracrine mechanisms and attenuate AAA expansion in a murine elastase model.

Methods: AAA was induced in C57BL/6 mice by topical treatment of the abdominal aorta with elastase. Human ASC or saline was injected i.v. within 4 hours of elastase treatment. The aortic diameter was measured by ultrasound and video micrometry. Monocytes/macrophages and lymphocyte sub-populations cells were quantified by flow cytometry. Regulatory T cells (Treg) and M2 macrophages were quantified by immunohistochemical (IHC) staining. ASC were labeled with Hoechst and their distributions in the lung and aorta were imaged fluorescent microscopy and confirmed by real-time PCR for human-specific Alu sequence.

Results: ASC significantly suppressed AAA expansion at 14 days (n=10/group, p<0.01). At Day 1 there was a significant increase in Tregs in ASC treated mice(n=5/group, p<0.01) with a concurrent decrease of CD4+CD28-, CD8+CD28- T cells, and neutrophils (n=5/group, p<0.05). At Day 7, activated monocytes (insert CD16++?) and total aortic tissue resident macrophages were decreased (n=10/group, p<0.05) with a significant polarization to the tissue reparative M2 phenotype (n=5/group, p<0.05). Hoescht labeled ASC were detected in the lung without engraftment in the aorta at 24 hrs and were cleared at 96 hrs. Transmembrane co-culture of human peripheral blood mononuclear cells with ASCs induced Treg, polarize macrophages to the M2 phenoype, inhibited neutrophil transmigration, and suppressed lymphocyte proliferation, as further supporting the mechanism of paracrine immunomodulation in the in vivo model of AAA.

Conclusion: Systemic injection of ASC significantly suppresses AAA formation by inducing anti-inflammatory immune cell phenotypes. These effects are mediated by release of paracrine factors and suggest that further characterization of the ASC secretome may lead to more potent recombinant protein therapies for AAA.

Intravenous xenogeneic transplantation of human adipose-derived stem cells improves left ventricular function and microvascular integrity in swine myocardial infarction model

OBJECTIVES

The potential for beneficial effects of adipose-derived stem cells (ASCs) on myocardial perfusion and left ventricular dysfunction in myocardial ischemia (MI) has not been tested following intravenous delivery.

METHODS

Surviving pigs following induction of MI were randomly assigned to 1 of 3 different groups: the placebo group (n = 7), the single bolus group (SB) (n = 7, 15 × 10(7) ASCs), or the divided dose group (DD) (n = 7, 5 × 10(7) ASCs/day for three consecutive days). Myocardial perfusion defect area and coronary flow reserve (CFR) were compared during the 28-day follow-up. Also, serial changes in the absolute number of circulating CD4(+) T and CD8(+) T cells were measured.

RESULTS

The increases in ejection fraction were significantly greater in both the SB and the DD groups compared to the placebo group (5.4 ± 0.9%, 3.7 ± 0.7%, and -0.4 ± 0.6%, respectively), and the decrease in the perfusion defect area was significantly greater in the SB group than the placebo group (-36.3 ± 1.8 and -11.5 ± 2.8). CFR increased to a greater degree in the SB and the DD groups than in the placebo group (0.9 ± 0.2, 0.8 ± 0.1, and 0.2 ± 0.2, respectively). The circulating number of CD8(+) T cells was significantly greater in the SB and DD groups than the placebo group at day 7 (3,687 ± 317/µL, 3,454 ± 787/µL, and 1,928 ± 457/µL, respectively). The numbers of small vessels were significantly greater in the SB and the DD groups than the placebo group in the peri-infarct area.

CONCLUSIONS

Both intravenous SB and DD delivery of ASCs are effective modalities for the treatment of MI in swine. Intravenous delivery of ASCs, with its immunomodulatory and angiogenic effects, is an attractive noninvasive approach for myocardial rescue.

Conditioned media from adipose stromal cells limit lipopolysaccharide-induced lung injury, endothelial hyperpermeability and apoptosis

Background

Acute Respiratory Distress Syndrome (ARDS) is a condition that contributes to morbidity and mortality of critically ill patients. We investigated whether factors secreted by adipose stromal cells (ASC) into conditioned media (ASC-CM) will effectively decrease lung injury in the model of lipopolysaccharide (LPS)-induced ARDS.

Methods

To assess the effect of ASC-CM on ARDS indices, intravenous delivery of ASC and ASC-CM to C57Bl/6 mice was carried out 4 h after LPS oropharyngeal aspiration; Evans Blue Dye (EBD) was injected intravenously 1 h prior to animal sacrifice (48 h post-LPS). Lungs were either fixed for histopathology, or used to extract bronchoalveolar lavage fluid (BALF) or EBD. To assess the effect of ASC-CM on endothelial barrier function and apoptosis, human pulmonary artery endothelial cells were treated with ASC-CM for 48-72 h.

Results

ASC-CM markedly reduced LPS-induced histopathologic changes of lung, protein extravasation into BALF, and suppressed the secretion of proinflammatory cytokines TNFα and IL6. White Blood Cells (WBC) from BALF of LPS-challenged mice receiving ASC-CM had decreased reactive oxygen species (ROS) generation compared to WBC from LPS-challenged mice receiving control media injection. Treatment of pulmonary endothelial monolayers with ASC-CM significantly suppressed H₂O₂-induced leakage of FITC dextran and changes in transendothelial resistance, as well as gap formation in endothelial monolayer. ASC-CM exposure reduced the percentage of endothelial cells expressing ICAM-1, and suppressed TNFα-induced expression of E-selectin and cleavage of caspase-3. ASC-CM reduced the endothelial level of pro-apoptotic protein Bim, but did not affect the level of Bcl-2, Bad, or Bad phosphorylation.

Conclusions

Factors secreted by ASC efficiently reduce ARDS indices, endothelial barrier hyperpermeability, and activation of pro-inflammatory and pro-apoptotic pathways in endothelium.

Human adipose-derived stromal/stem cells protect against STZ-induced hyperglycemia: analysis of hASC-derived paracrine effectors

Adipose-derived stromal/stem cells (ASCs) ameliorate hyperglycemia in rodent models of islet transplantation and autoimmune diabetes, yet the precise human ASC (hASC)-derived factors responsible for these effects remain largely unexplored. Here, we show that systemic administration of hASCs improved glucose tolerance, preserved β cell mass, and increased β cell proliferation in streptozotocin-treated nonobese diabetic/severe combined immunodeficient mice. Coculture experiments combining mouse or human islets with hASCs demonstrated that islet viability and function were improved by hASCs following prolonged culture or treatment with proinflammatory cytokines. Analysis of hASC-derived factors revealed vascular endothelial growth factor and tissue inhibitor of metalloproteinase 1 (TIMP-1) to be highly abundant factors secreted by hASCs. Notably, TIMP-1 secretion increased in the presence of islet stress from cytokine treatment, while TIMP-1 blockade was able to abrogate in vitro prosurvival effects of hASCs. Following systemic administration by tail vein injection, hASCs were detected in the pancreas and human TIMP-1 was increased in the serum of injected mice, while recombinant TIMP-1 increased viability in INS-1 cells treated with interleukin-1beta, interferon-gamma, and tumor necrosis factor alpha. In aggregate, our data support a model whereby factors secreted by hASCs, such as TIMP-1, are able to mitigate against β cell death in rodent and in vitro models of type 1 diabetes through a combination of local paracrine as well as systemic effects.

Adipose stromal cells differentiate along a smooth muscle lineage pathway upon endothelial cell contact via induction of activin A

RATIONALE

Adipose stromal cells (ASC) are therapeutically potent progenitor cells that possess properties of pericytes. In vivo, ASC in combination with endothelial cells (EC) establish functional multilayer vessels, in which ASC form the outer vessel layer and differentiate into mural cells.

OBJECTIVE

To identify factors responsible for ASC differentiation toward the smooth muscle cell phenotype via interaction with EC.

METHODS AND RESULTS

An in vitro model of EC cocultivation with ASC was used, in which EC organized into vascular cords, accompanied by ASC migration toward EC and upregulation of α-smooth muscle actin, SM22α, and calponin expression. Conditioned media from EC-ASC, but not from EC cultures, induced smooth muscle cell protein expression in ASC monocultures. EC-ASC cocultivation induced marked accumulation of activin A but not transforming growth factor-β1 in conditioned media. This was attributed to induction of activin A expression in ASC on contact with EC. Although transforming growth factor-β and activin A were individually sufficient to initiate expression of smooth muscle cell antigens in ASC, only activin A IgG blocked the effect of EC-ASC conditioned media. Although transforming growth factor-β was able to induce activin A expression in ASC, in cocultures this induction was transforming growth factor-β independent. In EC-ASC cocultures, activin A IgG or ALK4/5/7 receptor inhibitors blocked expression of α-smooth muscle actin in ASC in the absence of direct EC-cord contact, but this inhibition was circumvented in ASC by direct EC contact.

CONCLUSIONS

EC initiate a smooth muscle cell differentiation program in adjacent ASC and propagate this differentiation in distant ASC by induction of activin A expression.

Abstract 3589: Adipose stem cell-derived interferon gamma alters breast epithelial stem cell hierarchy

Autologous adipose stem cell transplantation is increasingly being used for soft tissue reconstruction, particularly after mastectomy. However, a recent study demonstrated recurrence of invasive ductal carcinoma in the breast within four months of autologous fat grafting. Previous studies have documented how cancer cells commandeer adipose stem cells (ASC) to support their survival by altering extracellular matrix composition and stiffness. This study focused on delineating the effects of ASCs on the self-renewal capacity of breast epithelial cells. The immortalized breast epithelial cell line MCF-10A, MCF-10A overexpressing Slug, and MCF-10A overexpressing SRC were examined using a mammosphere assay and flow cytometry for the effects of ASCs on their self-renewal and stem-luminal progenitor-differentiated cell surface marker profile. MCF-10A-Slug cells provided a unique model system to study breast epithelial cell dedifferentiation as Slug functions downstream of the breast cancer susceptibility gene BRCA1 and is a major suppressor of progenitor cell lineage commitment and differentiation. Interestingly, results with these established cell lines were reproduced in primary breast epithelial cells isolated from a high-risk patient. We show that secreted factors from ASCs promote self-renewal of all cell types examined. ASC co-culture or treatment with ASC conditioned media (CM) altered the number of CD49fhigh/EpCAMlow stem-like and CD49fmedium/EpCAMmedium luminal progenitor cells in 2D culture and mammosphere assays. ASCs secrete Interferon gamma (IFNγ), CD40 ligand, IL-23 and SERPINE1. Among these factors, only IFNγ treatment altered stem cell hierarchy; while MCF-10A-Slug cells displayed only luminal progenitor phenotype, cells treated with IFNγ contained a distinct stem-like cell population. These results suggest that paracrine activity of adipose stem cell-derived factors can either enhance dedifferentiation and promote proliferation of dormant tumor cells or predispose normal cells to transformation by blocking differentiation.

Financial support: Susan G. Komen For the Cure SAC110025 and Zeta Tau Sorority (HN)

Citation Format: Manjushree Anjanappa, Riesa M. Burnett, Stephanie Merfeld-Clauss, William A. Wooden, Keith L. March, Sunil Tholpady, Harikrishna Nakshatri. Adipose stem cell-derived interferon gamma alters breast epithelial stem cell hierarchy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3589. doi:10.1158/1538-7445.AM2014-3589

Regenerative therapeutic potential of adipose stromal cells in early stage diabetic retinopathy

Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. Early stage DR involves inflammation, vascular leakage, apoptosis of vascular cells and neurodegeneration. In this study, we hypothesized that cells derived from the stromal fraction of adipose tissue (ASC) could therapeutically rescue early stage DR features. Streptozotocin (STZ) induced diabetic athymic nude rats received single intravitreal injection of human ASC into one eye and saline into the other eye. Two months post onset of diabetes, administration of ASC significantly improved “b” wave amplitude (as measured by electroretinogram) within 1–3 weeks of injection compared to saline treated diabetic eyes. Subsequently, retinal histopathological evaluation revealed a significant decrease in vascular leakage and apoptotic cells around the retinal vessels in the diabetic eyes that received ASC compared to the eyes that received saline injection. In addition, molecular analyses have shown down-regulation in inflammatory gene expression in diabetic retina that received ASC compared to eyes that received saline. Interestingly, ASC were found to be localized near retinal vessels at higher densities than seen in age matched non-diabetic retina that received ASC. In vitro, ASC displayed sustained proliferation and decreased apoptosis under hyperglycemic stress. In addition, ASC in co-culture with retinal endothelial cells enhance endothelial survival and collaborate to form vascular networks. Taken together, our findings suggest that ASC are able to rescue the neural retina from hyperglycemia-induced degeneration, resulting in importantly improved visual function. Our pre-clinical studies support the translational development of adipose stem cell-based therapy for DR to address both retinal capillary and neurodegeneration.

Selective inhibition of pancreatic ductal adenocarcinoma cell growth by the mitotic MPS1 kinase inhibitor NMS-P715

Most solid tumors, including pancreatic ductal adenocarcinoma (PDAC), exhibit structural and numerical chromosome instability (CIN). Although often implicated as a driver of tumor progression and drug resistance, CIN also reduces cell fitness and poses a vulnerability that can be exploited therapeutically. The spindle assembly checkpoint (SAC) ensures correct chromosome-microtubule attachment, thereby minimizing chromosome segregation errors. Many tumors exhibit upregulation of SAC components such as MPS1, which may help contain CIN within survivable limits. Prior studies showed that MPS1 inhibition with the small molecule NMS-P715 limits tumor growth in xenograft models. In cancer cell lines, NMS-P715 causes cell death associated with impaired SAC function and increased chromosome missegregation. Although normal cells appeared more resistant, effects on stem cells, which are the dose-limiting toxicity of most chemotherapeutics, were not examined. Elevated expression of 70 genes (CIN70), including MPS1, provides a surrogate measure of CIN and predicts poor patient survival in multiple tumor types. Our new findings show that the degree of CIN70 upregulation varies considerably among PDAC tumors, with higher CIN70 gene expression predictive of poor outcome. We identified a 25 gene subset (PDAC CIN25) whose overexpression was most strongly correlated with poor survival and included MPS1. In vitro, growth of human and murine PDAC cells is inhibited by NMS-P715 treatment, whereas adipose-derived human mesenchymal stem cells are relatively resistant and maintain chromosome stability upon exposure to NMS-P715. These studies suggest that NMS-P715 could have a favorable therapeutic index and warrant further investigation of MPS1 inhibition as a new PDAC treatment strategy.

Intracoronary and retrograde coronary venous myocardial delivery of adipose-derived stem cells in swine infarction lead to transient myocardial trapping with predominant pulmonary redistribution

OBJECTIVES

To examine the comparative fate of adipose-derived stem cells (ASCs) as well as their impact on coronary microcirculation following either retrograde coronary venous (RCV) or arterial delivery.

BACKGROUND

Local delivery of ASCs to the heart has been proposed as a practical approach to limiting the extent of myocardial infarction. Mouse models of mesenchymal stem cell effects on the heart have also demonstrated significant benefits from systemic (intravenous) delivery, prompting a question about the advantage of local delivery. There has been no study addressing the extent of myocardial vs. systemic disposition of ASCs in large animal models following local delivery to the myocardium.

METHODS

In an initial experiment, dose-dependent effects of ASC delivery on coronary circulation in normal swine were evaluated to establish a tolerable ASC dosing range for intracoronary (IC) delivery. In a set of subsequent experiments, an anterior acute myocardial infarction (AMI) was created by balloon occlusion of the proximal left anterior descending (LAD) artery, followed by either IC or RCV infusion of 10(7) (111)Indium-labeled autologous ASCs 6 days following AMI. Indices of microcirculatory resistance (IMR) and coronary flow reserve (CFR) were measured before sacrifices to collect tissues for analysis at 1 or 24 hr after cell delivery.

RESULTS

IC delivery of porcine ASCs to normal myocardium was well tolerated up to a cumulative dose of 14 × 10(6) cells (approximately 0.5 × 10(6) cells/kg). There was evidence suggesting microcirculatory trapping of ASC: at unit doses of 50 × 10(6) ASCs, IMR and CFR were found to be persistently altered in the target LAD distribution at 7 days following delivery, whereas at 10 × 10(6) ASCs, only CFR was altered. In the context of recent MI, a significantly higher percentage of ASCs was retained at 1 hr with IC delivery compared with RCV delivery (57.2 ± 12.7% vs. 17.9 ± 1.6%, P = 0.037) but this initial difference was not apparent at 24 hr (22.6 ± 5.5% vs. 18.7 ± 8.6%; P = 0.722). In both approaches, most ASC redistributed to the pulmonary circulation by 24 hr postdelivery. There were no significant differences in CFR or IMR following ASC delivery to infarcted tissue by either route.

CONCLUSIONS

Selective intravascular delivery of ASC by coronary arterial and venous routes leads to similarly limited myocardial cell retention with predominant redistribution of cells to the lungs. IC arterial delivery of ASC leads to only transiently greater myocardial retention, which is accompanied by obstruction of normal regions of coronary microcirculation at higher doses. The predominant intrapulmonary localization of cells following local delivery via both methods prompts the notion that systemic delivery of ASC might provide similarly beneficial outcomes while avoiding risks of inadvertent microcirculatory compromise.