Vessel Maturation Research Articles

Tumor-specific interendothelial adhesion mediated by FLRT2 facilitates cancer aggressiveness.

Blood vessel abnormalization alters cancer cell metabolism and promotes cancer dissemination and metastasis. However, the biological features of the abnormalized blood vessels that facilitate cancer progression and whether they can be targeted therapeutically have not been fully investigated. Here, we found that an axon guidance molecule, fibronectin leucine-rich transmembrane protein 2 (FLRT2), is expressed preferentially in abnormalized vessels of advanced colorectal cancers in humans and that its expression correlates negatively with long-term survival. Endothelial cell–specific deletion of Flrt2 in mice selectively pruned abnormalized vessels, resulting in a unique metabolic state termed “oxygen-glucose uncoupling,” which suppressed tumor metastasis. Moreover, Flrt2 deletion caused an increase in the number of mature vessels, resulting in a significant increase in the antitumor effects of immune checkpoint blockers. Mechanistically, we found that FLRT2 forms noncanonical interendothelial adhesions that safeguard against oxidative stress through homophilic binding. Together, our results demonstrated the existence of tumor-specific interendothelial adhesions that enable abnormalized vessels to facilitate cancer aggressiveness. Targeting this type of adhesion complex could be a safe and effective therapeutic option to suppress cancer progression.

Seasonal patterns of increases in stem girth, vessel development, and hydraulic function in deciduous tree species.

The onset of spring growth and vessel formation were examined within three deciduous woody plant species, Acer rubrum, Populus balsamifera ssp. trichocarpa and Quercus rubra. We were broadly interested in the lag between the onset of girth expansion and the formation of mature and hydraulically conductive vessels within the new xylem. Dendrometers were installed on 20 trees (6-7 per species), and expansion of both bole and distal stems was monitored throughout the growing season in a common garden. For each species, four to six distal stems were harvested every other week for anatomical examination of vessel formation. Additionally, for Populus and Quercus, hydraulic conductivity measurements and active xylem staining were completed on all stem samples. For all three species, the timing of girth expansion was similar. Expansion of distal branches occurred 12-37 d earlier than that of the bole. Vessel formation initiated several weeks prior to leaf-out, but no new earlywood vessels were mature at the time of bud break for Acer and Populus and only a few were present in Quercus. Initial stem girth expansion occurred 2 to >6 weeks before the maturation of the first current-year vessels, and there was an additional delay of up to 4 weeks before mature vessels became hydraulically functional. Hydraulic conductivity was strongly correlated with the number and diameter of stained vessels. Bud break and leaf expansion relied predominantly on water supplied by vessels formed during prior seasons. Early-season activity is likely affected by the function of older xylem vessels and the environmental factors that influence their structure and function. Understanding the functional lifespan of vessels and the varying contributions of new and older vessels to conductivity are critical to understanding of the phenology and vascular function of long-lived woody plants in response to changing climates.

IMMUNOHISTOCHEMICAL ASSESSMENT OF LYMPHATIC VESSELS IN HUMAN LIVERS WITH CHRONIC HEPATITIS C - RELATION TO HISTOLOGICAL VARIABLES.

Viral hepatitis C is a significant public health challenge. The disease may remain clinically silent in both acute and chronic forms, and chronic infections may progress to advanced disease such as cirrhosis and hepatocellular carcinoma, requiring costly treatment, compromising the patient's quality of life and even leading to death. For this reason, it is one of the most frequent indications for liver transplantation. Although treatment with direct-acting antivirals represents remarkable progress, many patients are still infected and even those who cleared the viral infection must be followed due to their previous hepatic lesions, especially regarding the disturbances of lobular architecture and the sanguineal and lymphatic vessels. To assess immunohistochemical aspects of lymphatic sprouts and mature lymphatic vascularity with histological variables of liver injury attributable to hepatitis C virus (HCV) and fatty disease. The present study included 72 liver biopsies of cases with chronic hepatitis C. Morphologic changes reflecting "staging" and "activity" were analyzed. Immunohistochemical reactions were performed with monoclonal antibody D2-40 anti-podoplanin. Major histological variables were also semiquantified so as to enable the search for possible associations among histological and Immunohistochemical criteria, as well as with genotypes 1 and 3 of HCV. Histological findings showed that the different degrees of strutural changes were well represented in this casuistic. Intralobular/parenchymal necro-inflammatory activity was predominantly mild to moderate. Most cases did not show major evidences of fatty disease, which was found significantly higher in cases infected with HCV genotype 3. The amount of portal lymphatic sprouts increased along with the progression of structural changes, maximal at cirrhosis. Portal lymphatic sprouts as well as portal mature lymphatic vessels also showed an increase parallel to the increase in the degree of portal/septal inflammatory infiltrate. In the present study, no significant association was found between the proportion of portal lymphatic sprouts or portal mature lymphatic vessels and the degree of periportal/periseptal activity. No significant relations were detected between lymphatic sprouts/mature vessels and periportal or parenchymal inflammatory activity, nor with infections due to HCV genotype 1 or 3. Visualization and semiquantitation of sprouts and mature lymphatic vessels were clearly yielded by Immunohistochemical staining with monoclonal antibody D2-40. The amount of lymphatics was increased along fibrogenic process, significantly related to progression of liver disease and maximal at cirrhosis. No significant relations were detected with necro-inflammatory activity at interface or in the parenchyma.

Granular honeycomb scaffolds composed of carbonate apatite for simultaneous intra- and inter-granular osteogenesis and angiogenesis.

Granular porous calcium phosphate scaffolds are used for bone regeneration in dentistry. However, in conventional granules, the macropore interconnectivity is poor and has varying size. Herein, we developed a productive method for fabricating carbonate apatite honeycomb granules with uniformly sized macropores based on extrusion molding. Each honeycomb granule possesses three hexagonal macropores of ∼290 ​μm along its diagonal. Owing to these macropores, honeycomb granules simultaneously formed new and mature bone and blood vessels in both the interior and exterior of the granules at 4 weeks after implantation. The honeycomb granules are useful for achieving rapid osteogenesis and angiogenesis.

Establishment of a mouse model of pancreatic cancer using human pancreatic cancer cell line S2-013-derived organoid

A well-established preclinical model of pancreatic cancer needs to be established to facilitate research on new therapeutic targets. Recently established animal models of pancreatic cancer, including patient-derived tumor models and organoid models, are used for pre-clinical drug testing and biomarker discovery. These models have useful characteristics over conventional xenograft mouse models based on cell lines in preclinical studies, but still cannot accurately predict the clinical outcomes of new treatments and have not yet been broadly implemented in research. We employed pancreatic cancer organoid culture methods using the pancreatic cancer cell line S2-013, and performed pathological and immunohistochemical analyses to characterize tumor xenografts obtained from a mouse model implanted with S2-013 cell line-derived organoids. Serum levels of the pancreatic cancer tumor marker CA19-9 were measured by ELISA. We generated human pancreatic cancer organoids using a co-culture of S2-013 cells, human endothelial cells derived from human umbilical vein endothelial cells, and human mesenchymal stem cells, and established a mouse model with subcutaneously transplanted human pancreatic cancer organoids (S2-013-organoid model). Although blood clotting crater-like formation developed in the middle of subcutaneous xenografts in the S2-013-conventional model, created by subcutaneously injecting S2-013 cells into the right flank of nude mice, the size of xenografts in the S2-013-organoid model gradually increased without crater-like formation. Importantly, tumor xenografts obtained from the S2-013-organoid model exhibited a clinical human pancreatic cancer tissue-like cellular morphology, tissue architecture, and polarity, and actively formed cancer stroma containing mature blood vessels with the high expression of the vascular tight junction marker CD31. In subcutaneous xenografts of S2-013-conventional mice, no blood vessel density or widely expanding areas of necrotic regions were present. Consequently, serum levels of CA19-9 in the S2-013-organoid model correlated with tumor volumes. In addition, epithelial–mesenchymal transition, the conversion of epithelial cells to the mesenchymal phenotype, was observed in tumor xenografts of the S2-013-organoid model. The S2-013-organoid model provides tumor xenografts consisting of clinical human pancreatic cancer-like tissue formation with the effective development of vascularized stroma, and may be valuable for facilitating studies on pre-clinical drug testing and biomarker discovery.

A novel long-term intravenous combined with local treatment with human amnion-derived mesenchymal stem cells for a multidisciplinary rescued uremic calciphylaxis patient and the underlying mechanism.

Calciphylaxis is a rare disease characterized histologically by microvessel calcification and microthrombosis, with high mortality and no proven therapy. Here, we reported a severe uremic calciphylaxis patient with progressive skin ischemia, large areas of painful malodorous ulcers, and mummified legs. Because of the worsening symptoms and signs refractory to conventional therapies, treatment with human amnion-derived mesenchymal stem cells (hAMSCs) was approved. Preclinical release inspections of hAMSCs, efficacy, and safety assessment, including cytokine secretory ability, immunocompetence, tumorigenicity, and genetics analysis in vitro, were introduced. We further performed acute and long-term hAMSC toxicity evaluations in C57BL/6 mice and rats, abnormal immune response tests in C57BL/6 mice, and tumorigenicity tests in neonatal Balbc-nu nude mice. After the preclinical research, the patient was treated with hAMSCs by intravenous and local intramuscular injection and external supernatant application to the ulcers. When followed up to 15 months, the blood-based markers of bone and mineral metabolism improved, with skin soft tissue regeneration and a more favorable profile of peripheral blood mononuclear cells. Skin biopsy after 1-month treatment showed vascular regeneration with mature noncalcified vessels within the dermis, and 20 months later, the re-epithelialization restored the integrity of the damaged site. No infusion or local treatment-related adverse events occurred. Thus, this novel long-term intravenous combined with local treatment with hAMSCs warrants further investigation as a potential regenerative treatment for uremic calciphylaxis due to effects of inhibiting vascular calcification, stimulating angiogenesis and myogenesis, anti-inflammatory and immune modulation, multidifferentiation, re-epithelialization, and restoration of integrity.

Rethinking growth factors: the case of BMP9 during vessel maturation.

Angiogenesis is an essential process for correct development and physiology. This mechanism is tightly regulated by many signals that activate several pathways, which are constantly interacting with each other. There is mounting evidence that BMP9/ALK1 pathway is essential for a correct vessel maturation. Alterations in this pathway lead to the development of hereditary haemorrhagic telangiectasias. However, little was known about the BMP9 signalling cascade until the last years. Recent reports have shown that while BMP9 arrests cell cycle, it promotes the activation of anabolic pathways to enhance endothelial maturation. In light of this evidence, a new criterion for the classification of cytokines is proposed here, based on the physiological objective of the activation of anabolic routes. Whether this activation by a growth factor is needed to sustain mitosis or to promote a specific function such as matrix formation is a critical characteristic that needs to be considered to classify growth factors. Hence, the state-of-the-art of BMP9/ALK1 signalling is reviewed here, as well as its implications in normal and pathogenic angiogenesis.

The immunohistochemical detection of peroxiredoxin 1 and 2 in canine spontaneous vascular endothelial tumors.

Peroxiredoxin (PRDX) is an antioxidant enzyme family with six isoforms (PRDX1–6). The main function of PRDXs is to decrease cellular oxidative stress by reducing reactive oxygen species, such as hydrogen peroxide, to H2O. Recently, it has been reported that PRDXs are overexpressed in various malignant tumors in humans, and are involved in the development, proliferation, and metastasis of tumors. However, studies on the expression of PRDXs in tumors of animals are limited. Therefore, in the present study, we immunohistochemically investigated the expression of PRDX1 and 2 in spontaneous canine hemangiosarcoma (HSA) and hemangioma (HA), as well as in selected normal tissue and granulation tissue, including newly formed blood vessels. Although there were some exceptions, immunolocalization of PRDX1 and 2 in normal canine tissues was similar to those in humans, rats, or mice. In granulation tissue, angiogenic endothelial cells were strongly positive for PRDX1 and 2, whereas quiescent endothelial cells in mature vessels were negative. Both PRDX1 and 2 were significantly highly expressed in HSA compared to HA. There were no significant differences in the expression of PRDX1 and 2 among the subtypes and primary sites of HSA. These results suggest that PRDX1 and 2 may be involved in the angiogenic phenotypes of endothelial cells in granulation tissue as well as in the behavior in the malignant endothelial tumors.

Platelet rich plasma–complexed hydrogel glue enhances skin wound healing in a diabetic rat model

Diabetic patients often exhibit delayed or incomplete progress in the healing of acute wounds, owing to poor blood perfusion. Platelet-rich plasma (PRP) has attracted much attention as a means to improve wound healing, because it contains high growth factor concentrations. However, the burst-like release of PRP growth factors results in a short half-life of these therapeutic proteins, thus greatly limiting the therapeutic effect. In this study, we prepared PRP from human umbilical cord blood and developed an in situ photocrosslinkable PRP hydrogel glue (HNPRP) by adding a photoresponsive hyaluronic acid (HA-NB) into PRP. The HNPRP hydrogel allowed for controlled release of platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β (TGF-β) for up to 28 days. In vitro cell culture showed that HNPRP promoted migration of fibroblasts and keratinocytes as well as PRP and did not reveal the advantages of HNPRP. However, in a diabetic rat skin wound model, HNPRP treatment promoted faster wound closure. Furthermore, the HNPRP group, compared with the control, PRP and hydrogel only groups, showed significantly greater re-epithelialization and numbers of both newly formed and mature blood vessels. The HNPRP group also displayed higher collagen formation than did the control group. In conclusion, HNPRP enhances angiogenesis and skin regeneration and consequently achieves faster wound healing, thus extending its potential for clinical applications to treat diabetic skin wounds.

Oxidative pentose phosphate pathway controls vascular mural cell coverage by regulating extracellular matrix composition

Vascular mural cells (vMC) play an essential role in the development and maturation of the vasculature by promoting vessel stabilization through their interactions with endothelial cells (EC). Whether endothelial metabolism influences mural cell recruitment and differentiation is unknown. Here, we show that the oxidative Pentose Phosphate Pathway (oxPPP) in EC is required for establishing vMC coverage of the dorsal aorta (DA) during early vertebrate development in zebrafish and mice. We demonstrate that laminar shear stress (LSS) and blood flow maintain oxPPP activity, which, in turn, promotes Elastin (Eln) expression in blood vessels through production of ribose-5-phosphate (R5P). Eln is both necessary and sufficient to drive vMC recruitment and maintenance when the oxPPP is active. In summary, our work demonstrates that endothelial cell metabolism regulates blood vessel maturation by controlling vascular matrix composition and vMC recruitment.

Antiangiogenesis: Vessel Regression, Vessel Normalization, or Both?

The concepts of antiangiogenic tumor therapy were pioneered on the assumption that the inhibition of tumor angiogenesis should lead to the complete regression of the tumor-associated vasculature and thereby hold the tumor in an avascular dormant state. Yet, clinical trials revealed limited efficacy of angiogenesis inhibitors when used as monotherapy. Instead, antiangiogenic drugs proved effective to extend overall survival when used in combination with chemotherapy. This counterintuitive observation-inhibition of tumor vascularization should lead to less and not more delivery of chemotherapy to the tumor-led to the concepts of "vessel normalization." This refers to the notion that antiangiogenic drugs prune the most immature tumor vessels and spare mature vessels, thereby resulting in a more normal-appearing vasculature that leads to better access of chemotherapy to the tumor. The concepts of vessel normalization were first laid out in a landmark publication in Cancer Research in 2004. More than 600 studies on different aspects of vessel normalization have been published since then. Nevertheless, it is to this day less clear than ever to what extent vessel regression (leading to tumor starvation) and vessel normalization (facilitating chemotherapy) contribute to the clinical efficacy of antiangiogenic tumor therapy. This "Landmark Commentary" puts the concepts of tumor vessel normalization in historical context and develops thereupon some of the most burning questions in the field of translational angiogenesis research that need to be answered to further advance the application of tumor vascular stroma reprogramming therapies.See related article by Tong and colleagues, Cancer Res 2004;64:3731-6.

High Level of Staufen1 Expression Confers Longer Recurrence Free Survival to Non-Small Cell Lung Cancer Patients by Promoting THBS1 mRNA Degradation.

Stau1 is a pluripotent RNA-binding protein that is responsible for the post-transcriptional regulation of a multitude of transcripts. Here, we observed that lung cancer patients with a high Stau1 expression have a longer recurrence free survival. Strikingly, Stau1 did not impair cell proliferation in vitro, but rather cell migration and cell adhesion. In vivo, Stau1 depletion favored tumor progression and metastases development. In addition, Stau1 depletion strongly impaired vessel maturation. Among a panel of candidate genes, we specifically identified the mRNA encoding the cell adhesion molecule Thrombospondin 1 (THBS1) as a new target for Staufen-mediated mRNA decay. Altogether, our results suggest that regulation of THBS1 expression by Stau1 may be a key process involved in lung cancer progression.

AMSP-30 m as a novel HIF-1α inhibitor attenuates the development and severity of adjuvant-induced arthritis in rats: Impacts on synovial apoptosis, synovial angiogenesis and sonic hedgehog signaling pathway

Growing evidence indicates that synovial hypoxia-inducible factor 1α (HIF-1α) can be as a promising target for RA therapy. We previously reported that AMSP-30 m as a novel HIF-1α inhibitor had potent activities of anticancer metastasis. This study clarified the therapeutic effects of HIF-1α inhibitor AMSP-30 m on adjuvant-induced arthritis (AIA) in rats and explored the possible mechanisms. AMSP-30 m was given intraperitoneally to AIA rats, and its therapeutic effects and anti-inflammatory activity were evaluated. The influences of AMSP-30 m on synovial apoptosis, angiogenesis and sonic hedgehog (Shh) pathway were examined. We found that, accompanied with the inhibition of synovial HIF-1α expression, AMSP-30 m had potent anti-arthritic and anti-inflammatory effects on AIA rats, evidenced by the reduction in paw swelling, arthritis index, histopathological scores, and the production of IL-1β, IL-6, TNF-α in serum and synovial tissues. AMSP-30 m reduced synovial Ki67 expression and increased TUNEL-positive index, indicating its anti-proliferative and pro-apoptotic effects on AIA synovial cells, which was related to reducing Bcl-2 protein level and increasing Bax, cleaved caspase 3 protein levels. Additionally, AMSP-30 m showed anti-angiogenic effects within AIA synovium, indicated by the reduction of synovial VEGF expression and blood vessels number (especially CD31+/αSMA- immature vessels, but not CD31+/αSMA+ mature vessels). Moreover, AMSP-30 m inhibited the activation of synovial Shh pathway, suggested by the reduction of pathway-related proteins, like Shh, Smo, Gli-1, cyclin D1 and c-Myc. Collectively, HIF-1α inhibitor AMSP-30 m exerted potent anti-arthritic effects on AIA rats possibly by promoting synovial apoptosis, reducing synovial angiogenesis and inhibiting Shh pathway.

Assessing the Effects of VEGF Releasing Microspheres on the Angiogenic and Foreign Body Response to a 3D Printed Silicone-Based Macroencapsulation Device.

Macroencapsulation systems have been developed to improve islet cell transplantation but can induce a foreign body response (FBR). The development of neovascularization adjacent to the device is vital for the survival of encapsulated islets and is a limitation for long-term device success. Previously we developed additive manufactured multi-scale porosity implants, which demonstrated a 2.5-fold increase in tissue vascularity and integration surrounding the implant when compared to a non-textured implant. In parallel to this, we have developed poly(ε-caprolactone-PEG-ε-caprolactone)-b-poly(L-lactide) multiblock copolymer microspheres containing VEGF, which exhibited continued release of bioactive VEGF for 4-weeks in vitro. In the present study, we describe the next step towards clinical implementation of an islet macroencapsulation device by combining a multi-scale porosity device with VEGF releasing microspheres in a rodent model to assess prevascularization over a 4-week period. An in vivo estimation of vascular volume showed a significant increase in vascularity (* p = 0.0132) surrounding the +VEGF vs. −VEGF devices, however, histological assessment of blood vessels per area revealed no significant difference. Further histological analysis revealed significant increases in blood vessel stability and maturity (** p = 0.0040) and vessel diameter size (*** p = 0.0002) surrounding the +VEGF devices. We also demonstrate that the addition of VEGF microspheres did not cause a heightened FBR. In conclusion, we demonstrate that the combination of VEGF microspheres with our multi-scale porous macroencapsulation device, can encourage the formation of significantly larger, stable, and mature blood vessels without exacerbating the FBR.

Adult spiny mice (Acomys) exhibit endogenous cardiac recovery in response to myocardial infarction

Complex tissue regeneration is extremely rare among adult mammals. An exception, however, is the superior tissue healing of multiple organs in spiny mice (Acomys). While Acomys species exhibit the remarkable ability to heal complex tissue with minimal scarring, little is known about their cardiac structure and response to cardiac injury. In this study, we first examined baseline Acomys cardiac anatomy and function in comparison with commonly used inbred and outbred laboratory Mus strains (C57BL6 and CFW). While our results demonstrated comparable cardiac anatomy and function between Acomys and Mus, Acomys exhibited a higher percentage of cardiomyocytes displaying distinct characteristics. In response to myocardial infarction, all animals experienced a comparable level of initial cardiac damage. However, Acomys demonstrated superior ischemic tolerance and cytoprotection in response to injury as evidenced by cardiac functional stabilization, higher survival rate, and smaller scar size 50 days after injury compared to the inbred and outbred mouse strains. This phenomenon correlated with enhanced endothelial cell proliferation, increased angiogenesis, and medium vessel maturation in the peri-infarct and infarct regions. Overall, these findings demonstrate augmented myocardial preservation in spiny mice post-MI and establish Acomys as a new adult mammalian model for cardiac research.

Targeting Tie2 in the Tumor Microenvironment: From Angiogenesis to Dissemination.

Simple SummaryThe dissemination of cancer cells from their original location to distant organs where they grow, a process called metastasis, causes more than 90% of cancer deaths. The identification of the molecular mechanisms of metastasis and the development of anti-metastatic therapies are essential to increase patient survival. In recent years, targeting the tumor microenvironment has become a promising avenue to prevent both tumor growth and metastasis. As the tumor microenvironment contains not only cancer cells but also blood vessels, immune cells, and other non-cancerous cells, it is naïve to think that therapy only affects a single cell type in this complex environment. Here we review the importance, and ways to inhibit the function, of one therapeutic target: the receptor Tie2. Tie2 is a receptor present on the cell surface of several cell types within the tumor microenvironment and regulates tumor angiogenesis, growth, and metastasis to distant organs.The Tie2 receptor tyrosine kinase is expressed in vascular endothelial cells, tumor-associated macrophages, and tumor cells and has been a major focus of research in therapies targeting the tumor microenvironment. The most extensively studied Tie2 ligands are Angiopoietin 1 and 2 (Ang1, Ang2). Ang1 plays a critical role in vessel maturation, endothelial cell migration, and survival. Ang2, depending on the context, may function to disrupt connections between the endothelial cells and perivascular cells, promoting vascular regression. However, in the presence of VEGF-A, Ang2 instead promotes angiogenesis. Tie2-expressing macrophages play a critical role in both tumor angiogenesis and the dissemination of tumor cells from the primary tumor to secondary sites. Therefore, Ang-Tie2 signaling functions as an angiogenic switch during tumor progression and metastasis. Here we review the recent advances and complexities of targeting Tie2 signaling in the tumor microenvironment as a possible anti-angiogenic, and anti-metastatic, therapy and describe its use in combination with chemotherapy.

Abstract 11919: Igg1 Phosphorylcholine Diminishes Murine Atherosclerosis and Ameliorates Plaque Stability via Reduced Intraplaque Angiogenesis and Hemorrhage

Introduction: Phosphorylcholine (PC), one of the main oxLDL epitopes, is an important pro-inflammatory damage associated molecular pattern. Epidemiologic data show that natural anti-PC IgM protect against cardiovascular disease. Within atherosclerotic lesions, inflammation and angiogenesis are linked via VEGFA secreting CD163 + macrophages. PC antibodies are recognized for their anti-inflammatory properties, the effect of PC antibodies on intraplaque angiogenesis (IPA) and intraplaque hemorrhage (IPH) is yet unknown. Hypothesis: Newly developed IgG1 PC antibody (PCmAb) inhibits lesion development via IPA and IPH reduction in murine vein graft atherosclerosis. Methods: Hypercholesterolemic male ApoE3*Leiden mice received a (donor) caval vein interposition in the carotid artery and weekly ip injections of (5mg/kg) PCmAb (n=11) or vehicle (n=12) until sacrifice at day 28. Vein graft morphometry and lesion composition including IPA and IPH were evaluated via immunohistochemistry. In vitro PCmAb effects were investigated in Hemoglobin (Hb):Haptoglobin(Hp)-cultured THP-1 macrophages and HUVECs. Results: PCmAb significantly decreased vein graft media area (13%), intima lesion (25%), and increased lumen area with 53% compared to vehicle. PCmAb improved lesion stability by increasing collagen content (18%) and decreased macrophages presence (31%). VCAM-1 and ICAM-1 expression in the vessel wall were also reduced (29%, 36%). PCmAb resulted in 23% decreased CD163 + macrophages content in vein grafts whereas CD163 expression was reduced in Hb:Hp stimulated macrophages. PCmAb significantly reduced neovessel density (34%) and significant reduced EC proliferation and migration with and without oxLDL stimulation. Moreover, PCmAb enhanced maturation of intraplaque angiogenic vessels by increasing neovessel pericyte coverage in vivo (31%). Together, this resulted in a 62%reduction of IPH. Conclusions: PCmAb effectively inhibits murine atherosclerotic lesion formation. PCmAb reduces IPA and IPH by decreased neovessel density and macrophages influx via reduced expression of VCAM-1 and ICAM-1, and increased neovessel maturation in vein graft atherosclerosis. PCmAb holds promise as a new therapeutic approach for plaque stability.

Combined administration of laminin-221 and prostacyclin agonist enhances endogenous cardiac repair in an acute infarct rat heart

Although endogenous cardiac repair by recruitment of stem cells may serve as a therapeutic approach to healing a damaged heart, how to effectively enhance the migration of stem cells to the damaged heart is unclear. Here, we examined whether the combined administration of prostacyclin agonist (ONO1301), a multiple-cytokine inducer, and stem cell niche laminin-221 (LM221), enhances regeneration through endogenous cardiac repair. We administered ONO1301- and LM221-immersed sheets, LM221-immersed sheets, ONO1301-immersed sheets, and PBS-immersed sheets (control) to an acute infarction rat model. Four weeks later, cardiac function, histology, and cytokine expression were analysed. The combined administration of LM221 and ONO1301 upregulated angiogenic and chemotactic factors in the myocardium after 4 weeks and enhanced the accumulation of ILB4 positive cells, SMA positive cells, and platelet-derived growth factor receptor alpha (PDGFRα) and CD90 double-positive cells, leading to the generation of mature microvascular networks. Interstitial fibrosis reduced and functional recovery was prominent in LM221- and ONO1301-administrated hearts as compared with those in ONO1301-administrated or control hearts. LM221 and ONO1301 combination enhanced recruitment of PDGFRα and CD90 double-positive cells, maturation of vessels, and functional recovery in rat acute myocardial infarction hearts, highlighting a new promising acellular approach for the failed heart.

Abstract PO-097: Addition of losartan to FOLFIRINOX and chemoradiation reduces the expression of pro-invasive and immunosuppressive genes in locally-advanced pancreatic cancer

Abstract Purpose: A phase II trial in patients with locally-advanced pancreatic cancer (LAPC) revealed unprecedented rates of complete surgical resection after adding losartan (L) to FOLFIRINOX (FFX) chemotherapy followed by chemoradiation (CRT) (NCT01821729). The aim of this study was to identify potential mechanisms of benefit by assessing the effects of FFX-L+CRT and FFX+CRT on the stromal tumor microenvironment. Experimental Design: We performed a gene analysis of RNA extracted from pancreatic cancer (PC) tissue sections (NanoString nCounter PanCancer Immune Profiling Panel of 730 genes) and immunohistochemistry using surgical samples from patients treated with FFX+CRT (N=15), FFX-L+CRT (N=17) or underwent surgery upfront, without any neoadjuvant therapy (N=9). Results: In comparison to untreated PC, we found 314 and 243 differentially expressed genes (DEGs, adjusted p-value < 0.05) in FFX-L+CRT and FFX+CRT, respectively, and 54 DEGs between FFX-L+CRT and FFX+CRT. PCs from both neoadjuvant FFX-L+CRT and FFX+CRT had increased expression of genes linked to blood vessel maturation (CDH5, THBS1), transvascular migration of leukocytes (JAM3, PECAM1, MCAM, ICAM2), T cell activation (CD6, ALCAM, NFATC1), cytolytic activity of NK cells and T cells (GZMA, GZMB, GZMH, KLRB1) and dendritic cell (DC) related genes (CD209, CD1C, IL3RA). The FOXP3 gene — encoding for a transcription factor that regulates the activity of CD4+ regulatory T cells (Tregs)— was down-regulated in FFX-L+CRT versus untreated samples. Direct comparison of FFX-L+CRT versus FFX+CRT showed increased expression of genes involved in lymphocyte activation (NFATC4, DPP4, STAT5B), and reduced expression of genes that regulate B cell activity (CD22, TRAF3, MS4A1) and CEACAM6, which promotes PC invasion. We also analyzed the correlation of each gene (n=730) with overall survival (OS). For patients treated with FFX-L+CRT, improved OS was negatively correlated with genes that promote invasion in PC (PBK), B cell development and signaling (SYK, BLNK), infiltration of monocytes and macrophages in tumors (CCR2), immune checkpoint (BTLA) and inhibit angiogenesis (TNFSF15). In patients treated with FFX+CRT, OS was positively correlated with genes that stimulate inflammation (IL32), T cell and DC activation (CD48), presentation of glycolipid antigens (CD1E) and antigen processing and presentation by DCs (CD209). Immunohistochemistry studies revealed significantly less residual disease and a higher infiltration of CD8+CD3+ T cells in FFX-L+CRT than FFX+CRT treated tumors. In addition, in patients treated with FFX-L+CRT we found significantly fewer Tregs in PC lesions with a complete/near complete versus poor/no response, confirming our transcriptomic findings. Conclusions: Our findings suggest that FFX-L+CRT can normalize the vasculature, and reduce invasion and the immunosuppressive effects of B cells, CCR2-positive macrophages and Tregs, and thus improve treatment outcome in patients with LAPC, although additional studies are needed. Citation Format: Yves Boucher, Jessica M. Posada, Sonu Subudhi, Ashwin S. Kumar, Ivy X. Chen, Mei R. Ng, Mari Mino-Kenudson, Nilesh Talele, Dan G. Duda, Dai Fukumura, Janet E. Murphy, Jeffrey W. Clark, David P. Ryan, Carlos Fernandez-Del Castillo, Theodore S. Hong, Rakesh K. Jain. Addition of losartan to FOLFIRINOX and chemoradiation reduces the expression of pro-invasive and immunosuppressive genes in locally-advanced pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-097.

RETRACTED: Modulation of macrophage phenotype through controlled release of interleukin-4 from gelatine coatings on titanium surfaces.

Pro-inflammatory phenotype (M1) macrophages initiate angiogenesis, while their prolonged activation can induce chronic inflammation. Anti-inflammatory phenotype (M2) macrophages promote vessel maturation and tissue regeneration. Biomaterials which can promote M2 polarisation after appropriate inflammation should enhance angiogenesis and wound healing. Herein, Interleukin-4 (IL-4), an anti-inflammatory cytokine, was adsorbed onto a titanium surface. Then, a genipin cross-linked gelatine hydrogel was coated onto the surface to delay IL-4 release. The cross-linking degree of the hydrogel was modulated by the different amount of genipin to control release of IL-4. When 0.7 wt% (weight %) genipin was used as a cross-linker, the sample (GG07-I) released less IL-4 within the first several days, followed by a sustained release time to 14 d. Meanwhile, the release rate of IL-4 in GG07-I reached a peak between 3 d and 7 d. In culture with macrophages in vitro, GG07-I and GG07 exhibited good cytocompatibility. The phenotypical switch of macrophages stimulated by the samples was determined by FACS, ELISA and PCR. Macrophages cultured with GG07-I, GG07 and PT were firstly activated to the M1 phenotype by interferon-gamma (IFN-γ). Then, due to the release of IL-4 in 5 to 7 d, GG07-I enhanced CD206, increased the secretion and gene expression of M2 marker, such as interleukin-10 (IL-10), arginase-1 (ARG-1) and platelet derived growth factor-BB (PDGF- BB). GG07-I prompted the switch from M1 to M2 phenotype. Those appropriate secretion of cytokines would benefit both vascularisation and osseointegration. Thus, the biomaterial directing inflammatory reaction has good prospects for clinical treatments.