Design and preclinical evaluation of a novel apelin-based PET radiotracer targeting APJ receptor for molecular imaging of angiogenesis.

APJ has been extensively described in the pathophysiology of angiogenesis and cell proliferation. The prognostic value of APJ overexpression in many diseases is now established. This study aimed to design a PET radiotracer that specifically binds to APJ. Apelin-F13A-NODAGA (AP747) was synthesized and radiolabeled with gallium-68 ([68Ga]Ga-AP747). Radiolabeling purity was excellent (> 95%) and stable up to 2 h. Affinity constant of [67Ga]Ga-AP747 was measured on APJ-overexpressing colon adenocarcinoma cells and was in nanomolar range. Specificity of [68Ga]Ga-AP747 for APJ was evaluated in vitro by autoradiography and in vivo by small animal PET/CT in both colon adenocarcinoma mouse model and Matrigel plug mouse model. Dynamic of [68Ga]Ga-AP747 PET/CT biodistributions was realized on healthy mice and pigs for two hours, and quantification of signal in organs showed a suitable pharmacokinetic profile for PET imaging, largely excreted by urinary route. Matrigel mice and hindlimb ischemic mice were submitted to a 21-day longitudinal follow-up with [68Ga]Ga-AP747 and [68Ga]Ga-RGD2 small animal PET/CT. [68Ga]Ga-AP747 PET signal in Matrigel was significantly more intense than that of [68Ga]Ga-RGD2. Revascularization of the ischemic hind limb was followed by LASER Doppler. In the hindlimb, [68Ga]Ga-AP747 PET signal was more than twice higher than that of [68Ga]Ga-RGD2 on day 7, and significantly superior over the 21-day follow-up. A significant, positive correlation was found between the [68Ga]Ga-AP747 PET signal on day 7 and late hindlimb perfusion on day 21. We developed a new PET radiotracer that specifically binds to APJ, [68Ga]Ga-AP747 that showed more efficient imaging properties than the most clinically advanced tracer of angiogenesis, [68Ga]Ga-RGD2.

Resveratrol Reverses Endothelial Colony-Forming Cell Dysfunction in Adulthood in a Rat Model of Intrauterine Growth Restriction.

Individuals born after intrauterine growth restriction (IUGR) are at risk of developing cardiovascular diseases (CVDs). Endothelial dysfunction plays a role in the pathogenesis of CVDs; and endothelial colony-forming cells (ECFCs) have been identified as key factors in endothelial repair. In a rat model of IUGR induced by a maternal low-protein diet, we observed an altered functionality of ECFCs in 6-month-old males, which was associated with arterial hypertension related to oxidative stress and stress-induced premature senescence (SIPS). Resveratrol (R), a polyphenol compound, was found to improve cardiovascular function. In this study, we investigated whether resveratrol could reverse ECFC dysfunctions in the IUGR group. ECFCs were isolated from IUGR and control (CTRL) males and were treated with R (1 µM) or dimethylsulfoxide (DMSO) for 48 h. In the IUGR-ECFCs, R increased proliferation (5'-bromo-2'-deoxyuridine (BrdU) incorporation, p < 0.001) and improved capillary-like outgrowth sprout formation (in Matrigel), nitric oxide (NO) production (fluorescent dye, p < 0.01), and endothelial nitric oxide synthase (eNOS) expression (immunofluorescence, p < 0.001). In addition, R decreased oxidative stress with reduced superoxide anion production (fluorescent dye, p < 0.001); increased Cu/Zn superoxide dismutase expression (Western blot, p < 0.05); and reversed SIPS with decreased beta-galactosidase activity (p < 0.001), and decreased p16ink4a (p < 0.05) and increased Sirtuin-1 (p < 0.05) expressions (Western blot). No effects of R were observed in the CTRL-ECFCs. These results suggest that R reverses long-term ECFC dysfunctions related to IUGR.

Functional Impairment of Endothelial Colony Forming Cells (ECFC) in Patients with Severe Atherosclerotic Cardiovascular Disease (ASCVD).

Endothelial dysfunction is a key factor in atherosclerosis. However, the link between endothelial repair and severity of atherosclerotic cardiovascular disease (ASCVD) is unclear. This study investigates the relationship between ASCVD, markers of inflammation, and circulating endothelial progenitor cells, namely hematopoietic cells with paracrine angiogenic activity and endothelial colony forming cells (ECFC). Two hundred and forty-three subjects from the TELARTA study were classified according to the presence of clinical atherosclerotic disease. ASCVD severity was assessed by the number of involved vascular territories. Flow cytometry was used to numerate circulating progenitor cells (PC) expressing CD34 and those co-expressing CD45, CD34, and KDR. Peripheral blood mononuclear cells ex vivo culture methods were used to determine ECFC and Colony Forming Unit- endothelial cells (CFU-EC). The ECFC subpopulation was analyzed for proliferation, senescence, and vasculogenic properties. Plasma levels of IL-6 and VEGF-A were measured using Cytokine Array. Despite an increased number of circulating precursors in ASCVD patients, ASCVD impaired the colony forming capacity and the angiogenic properties of ECFC in a severity-dependent manner. Alteration of ECFC was associated with increased senescent phenotype and IL-6 levels. Our study demonstrates a decrease in ECFC repair capacity according to ASCVD severity in an inflammatory and senescence-associated secretory phenotype context.

Endothelial Colony-Forming Cells Dysfunctions Are Associated with Arterial Hypertension in a Rat Model of Intrauterine Growth Restriction.

Infants born after intrauterine growth restriction (IUGR) are at risk of developing arterial hypertension at adulthood. The endothelium plays a major role in the pathogenesis of hypertension. Endothelial colony-forming cells (ECFCs), critical circulating components of the endothelium, are involved in vasculo-and angiogenesis and in endothelium repair. We previously described impaired functionality of ECFCs in cord blood of low-birth-weight newborns. However, whether early ECFC alterations persist thereafter and could be associated with hypertension in individuals born after IUGR remains unknown. A rat model of IUGR was induced by a maternal low-protein diet during gestation versus a control (CTRL) diet. In six-month-old offspring, only IUGR males have increased systolic blood pressure (tail-cuff plethysmography) and microvascular rarefaction (immunofluorescence). ECFCs isolated from bone marrow of IUGR versus CTRL males displayed a decreased proportion of CD31+ versus CD146+ staining on CD45- cells, CD34 expression (flow cytometry, immunofluorescence), reduced proliferation (BrdU incorporation), and an impaired capacity to form capillary-like structures (Matrigel test), associated with an impaired angiogenic profile (immunofluorescence). These dysfunctions were associated with oxidative stress (increased superoxide anion levels (fluorescent dye), decreased superoxide dismutase protein expression, increased DNA damage (immunofluorescence), and stress-induced premature senescence (SIPS; increased beta-galactosidase activity, increased p16INK4a, and decreased sirtuin-1 protein expression). This study demonstrated an impaired functionality of ECFCs at adulthood associated with arterial hypertension in individuals born after IUGR.

Molecular profile and proangiogenic activity of the adipose-derived stromal vascular fraction used as an autologous innovative medicinal product in patients with systemic sclerosis.

OBJECTIVE: The autologous stromal vascular fraction (SVF) from adipose tissue is an alternative to cultured adipose-derived stem cells for use in regenerative medicine and represents a promising therapy for vasculopathy and hand disability in systemic sclerosis (SSc). However, the bioactivity of autologous SVF is not documented in this disease context. This study aimed to compare the molecular and functional profiles of the SVF-based medicinal product obtained from SSc and healthy subjects. METHODS: Good manufacturing practice (GMP)-grade SVF from 24 patients with SSc and 12 healthy donors (HD) was analysed by flow cytometry to compare the distribution of the CD45- and CD45+ haematopoietic cell subsets. The ability of SVF to form a vascular network was assessed using Matrigel in vivo assay. The transcriptomic and secretory profiles of the SSc-SVF were assessed by RNA sequencing and multiplex analysis, respectively, and were compared with the HD-SVF. RESULTS: The distribution of the leucocyte, endothelial, stromal, pericyte and transitional cell subsets was similar for SSc-SVF and HD-SVF. SSc-SVF retained its vasculogenic capacity, but the density of neovessels formed in SVF-loaded Matrigel implanted in nude mice was slightly decreased compared with HD-SVF. SSc-SVF displayed a differential molecular signature reflecting deregulation of angiogenesis, endothelial activation and fibrosis. CONCLUSIONS: Our study provides the first evidence that SSc does not compromise the vascular repair capacity of SVF, supporting its use as an innovative autologous biotherapy. The characterisation of the specific SSc-SVF molecular profile provides new perspectives for delineating markers of the potency of SVF and its targets for the treatment of SSc.

Microvesicles and Cancer Associated Thrombosis.

Microvesicles (MVs) are small membrane enclosed structures released into the extracellular space by virtually all cell types. Their composition varies according to the cell origin and the stimulus which caused their formation. They harbor functional molecules and participate in intercellular communication. Endothelium, inflammatory cells, and cancer cells produce procoagulant MVs which contribute to cancer-associated thrombosis (CAT) in animal models. The tissue factor (TF) conveyed by these MVs was shown to play a key role in different animal models of experimental CAT. Alternatively, other molecular mechanisms involving polyphosphates or phosphatidylethanolamine could also be involved. In clinical practice, an association between an increase in the number of TF-positive or the procoagulant activity of these MVs and the occurrence of CAT has indeed been demonstrated in pancreatic-biliary cancers, suggesting that they could behave as a biomarker predictive for CAT. However, to date, this association was not confirmed in other types of cancer. Potential causes explaining this limited associated between MVs and CAT are (1) the diversity of mechanisms associating MVs and different types of cancer; (2) a more complex role of MVs in hemostasis integrating their anticoagulant and fibrinolytic activity; and (3) the lack of sensitivity, reproducibility, and standardization of current methodologies permitting measurement of MVs. Each of these hypotheses constitutes an interesting exploration path for a future reassessment of the clinical interest of the MVs in CAT.

Extracellular Vesicles in Angiogenesis.

During the past decade, extracellular vesicles (EVs), which include apoptotic bodies, microvesicles, and exosomes, have emerged as important players in cell-to-cell communication in normal physiology and pathological conditions. EVs encapsulate and convey various bioactive molecules that are further transmitted to neighboring or more distant cells, where they induce various signaling cascades. The message delivered to the target cells is dependent on EV composition, which, in turn, is determined by the cell of origin and the surrounding microenvironment during EV biogenesis. Among their multifaceted role in the modulation of biological responses, the involvement of EVs in vascular development, growth, and maturation has been widely documented and their potential therapeutic application in regenerative medicine or angiogenesis-related diseases is drawing increasing interest. EVs derived from various cell types have the potential to deliver complex information to endothelial cells and to induce either pro- or antiangiogenic signaling. As dynamic systems, in response to changes in the microenvironment, EVs adapt their cargo composition to fine-tune the process of blood vessel formation. This article reviews the current knowledge on the role of microvesicles and exosomes from various cellular origins in angiogenesis, with a particular emphasis on the underlying mechanisms, and discusses the main challenges and prerequisites for their therapeutic applications.

Arginase upregulation and eNOS uncoupling contribute to impaired endothelium-dependent vasodilation in a rat model of intrauterine growth restriction.

Individuals born after intrauterine growth restriction (IUGR) are at increased risk of developing cardiovascular diseases in adulthood, notably hypertension (HTN). Alterations in the vascular system, particularly impaired endothelium-dependent vasodilation, may play an important role in long-term effects of IUGR. Whether such vascular dysfunction precedes HTN has not been fully established in individuals born after IUGR. Moreover, the intimate mechanisms of altered endothelium-dependent vasodilation remain incompletely elucidated. We therefore investigated, using a rat model of IUGR, whether impaired endothelium-dependent relaxation precedes the development of HTN and whether key components of the l-arginine-nitric oxide (NO) pathway are involved in its pathogenesis. Pregnant rats were fed with a control (CTRL, 23% casein) or low-protein diet (LPD, 9% casein) to induce IUGR. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography in 5- and 8-wk-old male offspring. Aortic rings were isolated to investigate relaxation to acetylcholine, NO production, endothelial NO synthase (eNOS) protein content, arginase activity, and superoxide anion production. SBP was not different at 5 wk but significantly increased in 8-wk-old offspring of maternal LPD (LP) versus CTRL offspring. In 5-wk-old LP versus CTRL males, endothelium-dependent vasorelaxation was significantly impaired but restored by preincubation with l-arginine or the arginase inhibitor S-(2-boronoethyl)-l-cysteine; NO production was significantly reduced but restored by l-arginine pretreatment; total eNOS protein, dimer-to-monomer ratio, and arginase activity were significantly increased; superoxide anion production was significantly enhanced but normalized by pretreatment with the NO synthase inhibitor Nω-nitro-l-arginine. In this model, IUGR leads to early-impaired endothelium-dependent vasorelaxation, resulting from arginase upregulation and eNOS uncoupling, which precedes the development of HTN.

Accelerated senescence of cord blood endothelial progenitor cells in premature neonates is driven by SIRT1 decreased expression.

Epidemiological and experimental studies indicate that early vascular dysfunction occurs in low-birth-weight subjects, especially preterm (PT) infants. We recently reported impaired angiogenic activity of endothelial colony-forming cells (ECFCs) in this condition. We hypothesized that ECFC dysfunction in PT might result from premature senescence and investigated the underlying mechanisms. Compared with ECFCs from term neonates (n = 18), ECFCs isolated from PT (n = 29) display an accelerated senescence sustained by growth arrest and increased senescence-associated ß-galactosidase activity. Increased p16(INK4a) expression, in the absence of telomere shortening, indicates that premature PT-ECFC aging results from stress-induced senescence. SIRT1 level, a nicotinamide adenine dinucleotide-dependent deacetylase with anti-aging activities, is dramatically decreased in PT-ECFCs and correlated with gestational age. SIRT1 deficiency is subsequent to epigenetic silencing of its promoter. Transient SIRT1 overexpression or chemical induction by resveratrol treatment reverses senescence phenotype, and rescues in vitro PT-ECFC angiogenic defect in a SIRT1-dependent manner. SIRT1 overexpression also restores PT-ECFC capacity for neovessel formation in vivo. We thus demonstrate that decreased expression of SIRT1 drives accelerated senescence of PT-ECFCs, and acts as a critical determinant of the PT-ECFC angiogenic defect. These findings lay new grounds for understanding the increased cardiovascular risk in individuals born prematurely and open perspectives for therapeutic strategy.

A switch toward angiostatic gene expression impairs the angiogenic properties of endothelial progenitor cells in low birth weight preterm infants.

Low birth weight (LBW) is associated with increased risk of cardiovascular diseases at adulthood. Nevertheless, the impact of LBW on the endothelium is not clearly established. We investigate whether LBW alters the angiogenic properties of cord blood endothelial colony forming cells (LBW-ECFCs) in 25 preterm neonates compared with 25 term neonates (CT-ECFCs). We observed that LBW decreased the number of colonies formed by ECFCs and delayed the time of appearance of their clonal progeny. LBW dramatically reduced LBW-ECFC capacity to form sprouts and tubes, to migrate and to proliferate in vitro. The angiogenic defect of LBW-ECFCs was confirmed in vivo by their inability to form robust capillary networks in Matrigel plugs injected in nu/nu mice. Gene profile analysis of LBW-ECFCs demonstrated an increased expression of antiangiogenic genes. Among them, thrombospondin 1 (THBS1) was highly expressed at RNA and protein levels in LBW-ECFCs. Silencing THBS1 restored the angiogenic properties of LBW-ECFCs by increasing AKT phosphorylation. The imbalance toward an angiostatic state provide a mechanistic link between LBW and the impaired angiogenic properties of ECFCs and allows the identification of THBS1 as a novel player in LBW-ECFC defect, opening new perspectives for novel deprogramming agents.

Adipose Tissue and Adipose-Tissue-Derived Cell Therapies for the Treatment of the Face and Hands of Patients Suffering from Systemic Sclerosis.

Adipose tissue is recognized as a valuable source of cells with angiogenic, immunomodulatory, reparative and antifibrotic properties and emerged as a therapeutic alternative for the regeneration and repair of damaged tissues. The use of adipose-tissue-based therapy is expanding in autoimmune diseases, particularly in Systemic Sclerosis (SSc), a disease in which hands and face are severely affected, leading to disability and a decrease in quality of life. Combining the advantage of an abundant supply of fat tissue and a high abundance of stem/stromal cells, fat grafting and adipose tissue-derived cell-based therapies are attractive therapeutic options in SSc. This review aims to synthesize the evidence to determine the effects of the use of these biological products for face and hands treatment in the context of SSc. This highlights several points: the need to use relevant effectiveness criteria taking into account the clinical heterogeneity of SSc in order to facilitate assessment and comparison of innovative therapies; second, it reveals some impacts of the disease on fat-grafting success; third, an important heterogeneity was noticed regarding the manufacturing of the adipose-derived products and lastly, it shows a lack of robust evidence from controlled trials comparing adipose-derived products with standard care.

Paracrine Effects of Adipose-Derived Cellular Therapies in an in Vitro Fibrogenesis Model of Human Vocal Fold Scarring.

OBJECTIVES/HYPOTHESIS: Vocal folds (VF) scarring leads to severe dysphonia which negatively impacts daily life of patients. Current therapeutic options are limited due in large part to the high complexity of the micro-structure of the VF. Innovative therapies derived from adipose tissue such as stromal vascular fraction (SVF) or adipose derived stromal/ stem cells (ASC) are currently being evaluated in this indication and paracrine anti-fibrotic effects are considered as predominant mechanisms. METHODS: The paracrine anti-fibrotic effects of SVF and ASC from healthy donors were tested in an innovative in vitro fibrogenesis model employing human VF fiboblasts (hVFF) and the principles of macromolecular crowding (MMC). Biosynthesis of collogen and alpha-smooth-muscle actin (αSMA) expression in hVFF were quantified after five days of indirect coculture with ASC or SVF using silver stain, western blot and RT-qPCR analysis. RESULTS: Fibrogenesis was promoted by addition of transforming growth factor beta 1 (TGFß1) combined with MMC characterized by an enhanced deposition of fibrillar collagens and the acquisition of a myofibroblast phenotype (overexpression of αSMA). Adipose-derived therapies led to a reduction in the αSMA expression and the collagen content was lower in hVFF co-cultivated with SVF. CONCLUSIONS: ASC and SVF promoted significant prevention of fibrosis in an in vitro fibrogenesis model through paracrine mechanisms, supporting further development of adipose-derived cellular therapies in VF scarring.

Combining systemic and locally applied cellular therapies for the treatment of systemic sclerosis.

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by a functional and structural alteration of the microvascular network associated with cutaneous and visceral fibrosis lesions. Conventional therapies are based on the use of immunomodulatory molecules and symptomatic management but often prove to be insufficient, particularly for patients suffering from severe and rapidly progressive forms of the disease. In this context, cellular therapy approaches could represent a credible solution with the goal to act on the different components of the disease: the immune system, the vascular system and the extracellular matrix. The purpose of this review is to provide an overview of the cellular therapies available for the management of SSc. The first part will focus on systemically injected therapies, whose primary effect is based on immunomodulatory properties and immune system resetting, including autologous hematopoietic stem cell transplantation and intravenous injection of mesenchymal stem cells. The second part will discuss locally administered regenerative cell therapies, mainly derived from adipose tissue, developed for the management of local complications as hand and face disabilities.

Tracking Radiolabeled Endothelial Microvesicles Predicts Their Therapeutic Efficacy: A Proof-of-Concept Study in Peripheral Ischemia Mouse Model Using SPECT/CT Imaging.

Microvesicles, so-called endothelial large extracellular vesicles (LEVs), are of great interest as biological markers and cell-free biotherapies in cardiovascular and oncologic diseases. However, their therapeutic perspectives remain limited due to the lack of reliable data regarding their systemic biodistribution after intravenous administration. METHODS: Applied to a mouse model of peripheral ischemia, radiolabeled endothelial LEVs were tracked and their in vivo whole-body distribution was quantified by microSPECT/CT imaging. Hindlimb perfusion was followed by LASER Doppler and motility impairment function was evaluated up to day 28 post-ischemia. RESULTS: Early and specific homing of LEVs to ischemic hind limbs was quantified on the day of ischemia and positively correlated with reperfusion intensity at a later stage on day 28 after ischemia, associated with an improved motility function. CONCLUSIONS: This concept is a major asset for investigating the biodistribution of LEVs issued from other cell types, including cancer, thus partly contributing to better knowledge and understanding of their fate after injection.

Involvement of Multiple Variants of Soluble CD146 in Systemic Sclerosis: Identification of a Novel Profibrotic Factor.

OBJECTIVE: Systemic sclerosis (SSc) is an autoimmune disorder characterized by excessive fibrosis, immune dysfunction, and vascular damage, in which the expression of many growth factors is deregulated. CD146 was recently described as a major actor in SSc. Since CD146 also exists as a circulating soluble form (sCD146) that acts as a growth factor in numerous angiogenic- and inflammation-related pathologies, we sought to identify the mechanisms underlying the generation of sCD146 and to characterize the regulation and functions of the different variants identified in SSc. METHODS: We performed in vitro experiments, including RNA-Seq and antibody arrays, and in vivo experiments using animal models of bleomycin-induced SSc and hind limb ischemia. RESULTS: Multiple forms of sCD146, generated by both shedding and alternative splicing of the primary transcript, were discovered. The shed form of sCD146 was generated from the cleavage of both long and short membrane isoforms of CD146 through ADAM-10 and TACE metalloproteinases, respectively. In addition, 2 novel sCD146 splice variants, I5-13-sCD146 and I10-sCD146, were identified. Of interest, I5-13-sCD146 was significantly increased in the sera of SSc patients (P < 0.001; n = 117), in particular in patients with pulmonary fibrosis (P < 0.01; n = 112), whereas I10-sCD146 was decreased (P < 0.05; n = 117). Further experiments revealed that shed sCD146 and I10-sCD146 displayed proangiogenic activity through the focal adhesion kinase and protein kinase Cε signaling pathways, respectively, whereas I5-13-sCD146 displayed profibrotic effects through the Wnt-1/ß-catenin/WISP-1 pathway. CONCLUSION: Variants of sCD146, and in particular the novel I5-13-sCD146 splice variant, could constitute novel biomarkers and/or molecular targets for the diagnosis and treatment of SSc and other angiogenesis- or fibrosis-related disorders.

Soluble CD146, a biomarker and a target for preventing resistance to anti-angiogenic therapy in glioblastoma.

RATIONALE: Glioblastoma multiforme (GBM) is a primary brain tumor with poor prognosis. The U.S. food and drug administration approved the use of the anti-VEGF antibody bevacizumab in recurrent GBM. However, resistance to this treatment is frequent and fails to enhance the overall survival of patients. In this study, we aimed to identify novel mechanism(s) responsible for bevacizumab-resistance in CD146-positive glioblastoma. METHODS: The study was performed using sera from GBM patients and human GBM cell lines in culture or xenografted in nude mice. RESULTS: We found that an increase in sCD146 concentration in sera of GBM patients after the first cycle of bevacizumab treatment was significantly associated with poor progression free survival and shorter overall survival. Accordingly, in vitro treatment of CD146-positive glioblastoma cells with bevacizumab led to a high sCD146 secretion, inducing cell invasion. These effects were mediated through integrin αvß3 and were blocked by mucizumab, a novel humanized anti-sCD146 antibody. In vivo, the combination of bevacizumab with mucizumab impeded CD146 + glioblastoma growth and reduced tumor cell dissemination to an extent significantly higher than that observed with bevacizumab alone. CONCLUSION: We propose sCD146 to be 1/ an early biomarker to predict and 2/ a potential target to prevent bevacizumab resistance in patients with glioblastoma.

TRAIL/Apo2L mediates the release of procoagulant endothelial microparticles induced by thrombin in vitro: a potential mechanism linking inflammation and coagulation.

Microparticles are small vesicles playing a crucial role in cell communication by promoting prothrombotic and proinflammatory responses. However, the molecular mechanisms underlying their release are still elusive. We previously established that thrombin promoted the generation of endothelial microparticles (EMPs). In the present study, gene profiling identified TRAIL/Apo2L, a cytokine belonging to the tumor necrosis factor-alpha superfamily, as a target of thrombin. Thrombin increased the expression of cell-associated and soluble forms of TRAIL (sTRAIL) in HMEC-1 cells and human umbilical vein endothelial cells (HUVECs). Blocking TRAIL by specific antibodies or by small interfering RNA reduced both the number and the procoagulant activity of EMPs released by thrombin. Consistent with an involvement of sTRAIL in thrombin-induced EMP release, we showed that (1) exogenously added sTRAIL generated procoagulant EMPs; (2) supernatants from thrombin-stimulated endothelial cells induced EMP release by HMEC-1 cells and HUVECs, whereas those recovered from TRAIL knockdown endothelial cells displayed no effect. TRAIL/TRAIL-R2 complex mediated EMP release by initiating the recruitment of adaptor proteins and the activation of nuclear factor kappaB. Moreover, sTRAIL modulated intercellular adhesion molecule-1 and interleukin-8 expression induced by thrombin by a downstream pathway involving nuclear factor kappaB activation. Our data reveal a novel mechanism controlling EMP release and identify TRAIL as a key partner in the pathway linking coagulation and inflammation elicited by thrombin.

Development and Validation of a Fully GMP-Compliant Process for Manufacturing Stromal Vascular Fraction: A Cost-Effective Alternative to Automated Methods.

The therapeutic use of adipose-derived stromal vascular fraction (SVF) is expanding in multiple pathologies. Various processes have been proposed for manufacturing SVF but they must be revisited based on advanced therapy medicinal product (ATMP) regulations. We report here the development and validation of a fully good manufacturing practices (GMP)-compliant protocol for the isolation of SVF. Adipose tissue was collected from healthy volunteers undergoing lipoaspiration. The optimal conditions of collagenase digestion and washing were determined based on measurements of SVF cell viability, yield recovery, and cell subset distribution. Comparability of the SVF obtained using the newly developed manufacturing process (n = 6) and the Celution-based automated method (n = 33), used as a reference, was established using inter-donor analyses. Characteristics of SVF (n = 5) generated using both manufacturing protocols were analyzed for an intra-donor comparison. In addition, these comparisons also included the determination of colony-forming unit fibroblast frequency, in vitro angiogenic activity, and in vivo regenerative effects in a mouse ischemic cutaneous wound model. We successfully developed a process for the generation of SVF presenting higher cell viability and yield recovery compared to the Celution device-based protocol. Characteristics of the SVF including phenotype, capacity for angiogenesis, and wound-healing promotion attested to the comparability of the two manufacturing processes. We validated an optimized non-automated process that should allow for a GMP-compliant, more affordable, and reduced-cost strategy to exploit the potential of SVF-based regenerative therapies.