Endogenous IL-1 receptor antagonist restricts healthy and malignant myeloproliferation.

Here we explored the role of interleukin-1ß (IL-1ß) repressor cytokine, IL-1 receptor antagonist (IL-1rn), in both healthy and abnormal hematopoiesis. Low IL-1RN is frequent in acute myeloid leukemia (AML) patients and represents a prognostic marker of reduced survival. Treatments with IL-1RN and the IL-1ß monoclonal antibody canakinumab reduce the expansion of leukemic cells, including CD34+ progenitors, in AML xenografts. In vivo deletion of IL-1rn induces hematopoietic stem cell (HSC) differentiation into the myeloid lineage and hampers B cell development via transcriptional activation of myeloid differentiation pathways dependent on NFκB. Low IL-1rn is present in an experimental model of pre-leukemic myelopoiesis, and IL-1rn deletion promotes myeloproliferation, which relies on the bone marrow hematopoietic and stromal compartments. Conversely, IL-1rn protects against pre-leukemic myelopoiesis. Our data reveal that HSC differentiation is controlled by balanced IL-1ß/IL-1rn levels under steady-state, and that loss of repression of IL-1ß signaling may underlie pre-leukemic lesion and AML progression.

Imaging-guided nanomedicine development.

Nanomedicine research is an active field that produces thousands of studies every year. However, translation of nanotherapeutics to the clinic has yet to catch up with such a vast output. In recent years, the need to better understand nanomedicines' in vivo behavior has been identified as one of the major challenges for efficient clinical translation. In this context, noninvasive imaging offers attractive solutions to provide valuable information about nanomedicine biodistribution, pharmacokinetics, stability, or therapeutic efficacy. Here, we review the latest imaging approaches used in the development of therapeutic nanomedicines, discuss why these strategies bring added value along the translational pipeline, and give a perspective on future advances in the field.

Application of low-intensity pulsed therapeutic ultrasound on mesenchymal precursors does not affect their cell properties.

Ultrasound is considered a safe and non-invasive tool in regenerative medicine and has been used in the clinic for more than twenty years for applications in bone healing after the approval of the Exogen device, also known as low-intensity pulsed ultrasound (LIPUS). Beyond its effects on bone health, LIPUS has also been investigated for wound healing of soft tissues, with positive results for various cell processes including cell proliferation, migration and angiogenesis. As LIPUS has the potential to treat chronic skin wounds, we sought to evaluate the effects produced by a conventional therapeutic ultrasound device at low intensities (also considered LIPUS) on the migration capacity of mouse and human skin mesenchymal precursors (s-MPs). Cells were stimulated for 3 days (20 minutes per day) using a traditional ultrasound device with the following parameters: 100 mW/cm2 with 20% duty cycle and frequency of 3 MHz. At the parameters used, ultrasound failed to affect s-MP proliferation, with no evident changes in morphology or cell groupings, and no changes at the cytoskeletal level. Further, the migration and invasion ability of s-MPs were unaffected by the ultrasound protocol, and no major changes were detected in the gene/protein expression of ROCK1, integrin ß1, laminin ß1, type I collagen and transforming growth factor ß1. Finally, RNA-seq analysis revealed that only 10 genes were differentially expressed after ultrasound stimulation. Among them, 5 encode for small nuclear RNAs and 2 encode for proteins belonging to the nuclear pore complex. Considering the results overall, while the viability of s-MPs was not affected by ultrasound stimulation and no changes were detected in proliferation/migration, RNA-seq analysis would suggest that s-MPs do respond to ultrasound. The use of 100 mW/cm2 intensity or conventional therapeutic ultrasound devices might not be optimal for the stimulation the properties of cell populations. Future studies should investigate the potential application of ultrasound using variations of the tested parameters.

Radio-endoscopic diagnosis of Dieulafoy's lesion in a duodenal diverticulum.

We report the case of a patient with a Dieulafoy lesion within a duodenal diverticulum, showing the radiographic images. In this case the use of radiological techniques was of great help for diagnosis, bearing in mind that bleeding from this lesion may be intermittent and had not been revealed by the first endoscopic procedure. Since strong clinical suspicion persisted of active upper GI bleeding an angio-CT scan was performed, which allowed to orient diagnosis and rule out other causes of bleeding inaccessible to endoscopy.

Ultrasound Therapy: Experiences and Perspectives for Regenerative Medicine.

Ultrasound has emerged as a novel tool for clinical applications, particularly in the context of regenerative medicine. Due to its unique physico-mechanical properties, low-intensity ultrasound (LIUS) has been approved for accelerated fracture healing and for the treatment of established non-union, but its utility has extended beyond tissue engineering to other fields, including cell regeneration. Cells and tissues respond to acoustic ultrasound by switching on genetic repair circuits, triggering a cascade of molecular signals that promote cell proliferation, adhesion, migration, differentiation, and extracellular matrix production. LIUS also induces angiogenesis and tissue regeneration and has anti-inflammatory and anti-degenerative effects. Accordingly, the potential application of ultrasound for tissue repair/regeneration has been tested in several studies as a stand-alone treatment and, more recently, as an adjunct to cell-based therapies. For example, ultrasound has been proposed to improve stem cell homing to target tissues due to its ability to create a transitional and local gradient of cytokines and chemokines. In this review, we provide an overview of the many applications of ultrasound in clinical medicine, with a focus on its value as an adjunct to cell-based interventions. Finally, we discuss the various preclinical and clinical studies that have investigated the potential of ultrasound for regenerative medicine.

Adipokines disrupt cardiac differentiation and cardiomyocyte survival.

BACKGROUND: The role of adipose tissue in the pathophysiology of cardiovascular disease remains a major subject of research. The objective of the present study was to dissect the molecular mechanisms that regulate the survival and differentiation of cardiac cells in an obese environment. MATERIAL AND METHODS: We isolated murine/human cardiac cells from adult hearts of control and obese mice/subjects and analyzed the communication between cardiac cells and adipocytes in vitro, as well as the effects on their main functions such as survival and differentiation. RESULTS: We found that the presence of visceral or subcutaneous adipocytes in the environment of cardiomyocytes or cardiac precursors provoked apoptosis or blocked differentiation, respectively, and these effects were mediated by secreted adipokines. Remarkably, cardiac precursors changed their fate and differentiated into mature adipocytes, contributing to the overall increase in adipose cell content. Inhibiting the adipokines TNF-α, visfatin, or HMGB1 could block the deleterious effects of adipokines on cardiac cells. CONCLUSIONS: Our findings demonstrate that mouse and human visceral adipose tissue contributes negatively to the homeostasis and regeneration of the heart. Moreover, our results suggest that blocking the action of certain adipokines might enhance cardiac differentiation and survival.

Nestin-expressing progenitor cells: function, identity and therapeutic implications.

The neuroepithelial stem cell protein, or Nestin, is a cytoskeletal intermediate filament initially characterized in neural stem cells. However, current extensive evidence obtained in in vivo models and humans shows presence of Nestin+ cells with progenitor and/or regulatory functions in a number of additional tissues, remarkably bone marrow. This review presents the current knowledge on the role of Nestin in essential stem cell functions, including self-renewal/proliferation, differentiation and migration, in the context of the cytoskeleton. We further discuss the available in vivo models for the study of Nestin+ cells and their progeny, their function and elusive nature in nervous system and bone marrow, and their potential mechanistic role and promising therapeutic value in preclinical models of disease. Future improved in vivo models and detection methods will allow to determine the true essence of Nestin+ cells and confirm their potential application as therapeutic target in a range of diseases.

Membrane Blebbing Is Required for Mesenchymal Precursor Migration.

Mesenchymal precursors (MPs) present some advantageous features, such as differentiation and migration, which make them promising candidates for cell therapy. A better understanding of MP migration characteristics would aid the development of cell delivery protocols. Traditionally, cell migration is thought to occur only through the formation of lamellipodia. More recently, contractility-driven bleb formation has emerged as an alternative mechanism of motility. Here we report that MPs derived from different tissues present spontaneously dynamic cytoplasmic projections in sub-confluent culture, which appear as a combination of lamellipodia with blebs in the leading edge. Upon initial seeding, however, only bleb structures could be observed. Immunofluorescence revealed the presence of pERM, RhoA and F-actin during the blebbing process. Results from migration assays in the presence of blebbistatin, a myosin II inhibitor, showed that bleb formation correlated with migratory capacity, suggesting a functional role for blebs in migration. Bleb formation might be a useful mechanism to improve cell migration in cellular therapy protocols.

Obesity-driven alterations in adipose-derived stem cells are partially restored by weight loss.

OBJECTIVE: The therapeutic potential of adipose-derived stem cells (ASCs) is reduced by various stress-inducing conditions that affect tissue homeostasis such as diabetes, aging, and obesity. Previous works have provided evidence of negative effects of obesity on ASC populations, but it is unclear whether this persists after a weight loss. This study evaluated whether weight loss can restore the attenuated properties found in ASCs derived from populations with obesity (oASCs). METHODS: In vitro functional analyses were performed to investigate the possible recovery properties in mouse oASCs. Using ASCs isolated from subcutaneous tissue from formerly obese mice (dASCs) and control mice (cASCs), cell proliferation, viability, and some regenerative properties in these cells were analyzed compared with oASCs to evaluate the functional cell state. RESULTS: Cell proliferation, viability, and some regenerative properties are strengthened in dASCs and cASCs compared with oASCs. Nevertheless, metabolic analysis reveals a mitochondrial load misbalance and function leading to impaired respiration in dASCs. CONCLUSIONS: This study demonstrates that an initial obese environment triggers a detrimental state in ASCs that is not completely recovered after weight loss.

Low-Intensity Pulsed Ultrasound Improves the Functional Properties of Cardiac Mesoangioblasts.

Cell-based therapy is a promising approach for many diseases, including ischemic heart disease. Cardiac mesoangioblasts are committed vessel-associated progenitors that can restore to a significant, although partial, extent, heart structure and function in a murine model of myocardial infarction. Low-intensity pulsed ultrasound (LIPUS) is a non-invasive form of mechanical energy that can be delivered into biological tissues as acoustic pressure waves, and is widely used for clinical applications including bone fracture healing. We hypothesized that the positive effects of LIPUS on bone and soft tissue, such as increased cell differentiation and cytoskeleton reorganization, could be applied to increase the therapeutic potential of mesoangioblasts for heart repair. In this work, we show that LIPUS stimulation of cardiac mesoangioblasts isolated from mouse and human heart results in significant cellular modifications that provide beneficial effects to the cells, including increased malleability and improved motility. Additionally, LIPUS stimulation increased the number of binucleated cells and induced cardiac differentiation to an extent comparable with 5'-azacytidine treatment. Mechanistically, LIPUS stimulation activated the BMP-Smad signalling pathway and increased the expression of myosin light chain-2 together with upregulation of ß1 integrin and RhoA, highlighting a potentially important role for cytoskeleton reorganization. Taken together, these results provide functional evidence that LIPUS might be a useful tool to explore in the field of heart cell therapy.

Altered metabolic and stemness capacity of adipose tissue-derived stem cells from obese mouse and human.

Adipose stem cells (ASCs) are an appealing source of cells for therapeutic intervention; however, the environment from which ASCs are isolated may impact their usefulness. Using a range of functional assays, we have evaluated whether ASCs isolated from an obese environment are comparable to cells from non-obese adipose tissue. Results showed that ASCs isolated from obese tissue have a reduced proliferative ability and a loss of viability together with changes in telomerase activity and DNA telomere length, suggesting a decreased self-renewal capacity. Metabolic analysis demonstrated that mitochondrial content and function was impaired in obese-derived ASCs resulting in changes in favored oxidative substrates. These findings highlight the impact of obesity on adult stem properties. Hence, caution should be exercised when considering the source of ASCs for cellular therapies since their therapeutic potential may be impaired.

The potential of stem cells in the treatment of cardiovascular diseases.

Although the adult mammalian heart was once believed to be a post-mitotic organ without any capacity for regeneration, recent findings have challenged this dogma. A modified view assigns to the mammalian heart a measurable capacity for regeneration throughout life. The ultimate goals of the cardiac regeneration field have been pursued by multiple strategies, including understanding the developmental biology of cardiomyocytes and cardiac stem and progenitor cells, applying chemical genetics, and engineering biomaterials and delivery methods that facilitate cell transplantation. Successful stimulation of endogenous regenerative capacity in injured adult mammalian hearts can benefit from studies of natural cardiac regeneration.

Obese-derived ASCs show impaired migration and angiogenesis properties.

Efficient delivery of stem cells to target tissues is a major problem in regenerative medicine. Adipose derived stem cells have been proposed as important tools in cell therapy for recovering tissues after damage. Nevertheless, the ability of these ASCs to migrate or invade in order to reach the tissue of interest has not been tested so far. In this study we present evidence that the ASCs derived from obese subjects present a detrimental ability to migrate and invade in comparison with ASCs derived from control subjects. Besides, obese-derived ASCs are unable to respond to certain stimuli and to form enough capillaries after stimulation. We propose that the use of specific cytokines could overcome these deficiencies of the obese environment, offering a tool to optimize cell therapy.

Metabolic rescue of obese adipose-derived stem cells by Lin28/Let7 pathway.

Adipose-derived stem cells (ASCs) are promising candidates for autologous cell-based regeneration therapies by virtue of their multilineage differentiation potential and immunogenicity; however, relatively little is known about their role in adipose tissue physiology and dysfunction. Here we evaluated whether ASCs isolated from nonobese and obese tissue differed in their metabolic characteristics and differentiation potential. During differentiation to mature adipocytes, mouse and human ASCs derived from nonobese tissues both increased their insulin sensitivity and inhibition of lipolysis, whereas obese-derived ASCs were insulin-resistant, showing impaired insulin-stimulated glucose uptake and resistance to the antilipolytic effect of insulin. Furthermore, obese-derived ASCs showed enhanced release of proinflammatory cytokines and impaired production of adiponectin. Interestingly, the delivery of cytosol from control ASCs into obese-derived ASCs using a lipid-based, protein-capture methodology restored insulin sensitivity on glucose and lipid metabolism and reversed the proinflammatory cytokine profile, in part due to the restoration of Lin28 protein levels. In conclusion, glucose and lipid metabolism as well as maturation of ASCs is truncated in an obese environment. The reversal of the altered pathways in obese cells by delivery of normal subcellular fractions offers a potential new tool for cell therapy.

Method for obtaining committed adult mesenchymal precursors from skin and lung tissue.

AIMS: The present study reports an easy and efficient method for obtaining adult mesenchymal precursors from different adult mouse tissues. MATERIALS AND METHODS: We describe the isolation and expansion of mesenchymal precursors from skin and lung by a non-enzymatic method. Skin and lung mesenchymal precursors isolated by a modified explant technique were characterized in vitro by defined morphology and by a specific gene expression profile and surface markers. RESULTS AND CONCLUSIONS: Our results show that these precursors express stem cell and mesenchymal surface markers as well as epithelial markers. However, they are negative for markers of endothelium, cardiac and skeletal muscle or adipose tissue, indicating that they have initiated commitment to the tissues from which were isolated. These precursors can migrate without any stimulus and in response to stimuli as SDF1, MCP1 and TNFα and can be differentiated into epithelial lineages. Based on the properties of these precursors from adult tissues, we propose their use as tools for regenerative biomedicine.