Search Results (25)

Arteriogenesis, the growth of pre-existing arterioles into functional collateral arteries, represents a key adaptive response to severe arterial stenosis. This process is driven by hemodynamic forces and a tightly coordinated inflammatory cascade. Here, we investigated the effects of pharmacological stimulation of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) signaling pathway using the phosphodiesterase-5 (PDE5) inhibitor Sildenafil on collateral vessel growth in a murine model of femoral artery ligation (FAL). Flow cytometric analyses revealed that Sildenafil treatment significantly enhanced platelet–leukocyte aggregate formation, a prerequisite for the subsequent initiation of a localized perivascular inflammation. Histological and immunofluorescence analyses further demonstrated a marked increase in mast cell recruitment and degranulation at early time points (days 1 and 3 post-FAL). In addition, Sildenafil promoted perivascular macrophage accumulation on days 3 and 7, with a pronounced shift toward an M2-like pro-regenerative polarization state, ultimately resulting in the enhanced proliferation of vascular cells and the enlargement of collateral diameters. Together, these findings identify Sildenafil as a potent enhancer of arteriogenesis through coordinated immune cell activation, stimulating vascular cell proliferation along with positive collateral outward remodeling. Thus, Sildenafil emerges as a promising therapeutic candidate to promote collateral artery growth in cardiovascular occlusive diseases. Full article

Multidrug resistance (MDR) presents a significant challenge in the treatment of glioblastoma. We evaluated six novel adamantane–sclareol hybrids that integrate a natural labdane diterpene scaffold with an adamantane moiety to address this issue. Compounds 2, 5, and 6 demonstrated the ability to bypass P-glycoprotein (P-gp)-mediated resistance in resistant U87-TxR cells and induced collateral sensitivity, with compound 2 exhibiting the highest selectivity for glioblastoma compared to normal glial cells. Mechanistic studies revealed that compounds 2 and 5 selectively triggered early apoptosis in MDR cells, significantly elevated levels of H₂O₂ and peroxynitrite, and disrupted mitochondrial membrane potential. Additionally, these compounds altered the expression of key genes involved in glutathione (GSH) and thioredoxin (Trx) antioxidant defense systems and increased ASK1 protein levels, indicating the activation of ROS-driven apoptotic signaling. Both compounds inhibited P-gp function, leading to enhanced intracellular accumulation of rhodamine 123 (Rho 123) and synergistically sensitized U87-TxR cells to paclitaxel (PTX). A preliminary Rag1 xenograft study demonstrated that compound 5 effectively suppressed tumor growth without causing significant weight loss. Collectively, these findings position adamantane–sclareol hybrids, particularly compounds 2 and 5, as promising strategies that exploit an MDR-associated reactive oxygen species (ROS) vulnerability, combining selective cytotoxicity, redox disruption, and P-gp modulation to eliminate resistant glioblastoma cells and enhance the efficacy of chemotherapeutics. Full article

Background/Objectives: Clopidogrel is a P2Y₁₂ receptor inhibitor commonly used as antiplatelet therapy for patients with cardiovascular occlusive diseases. However, its role in vascular remodeling remains poorly understood. Platelets orchestrate the sterile inflammation in arteriogenesis, an endogenous process to bypass an occluded artery. Therefore, we investigated the impact of P2Y₁₂-inhibition by Clopidogrel on arteriogenesis. Methods: In this study, we utilized a well-established murine hindlimb model of arteriogenesis. To quantify the growth of collateral arteries, we employed laser-Doppler perfusion measurements and immunohistological analysis of growing compared to resting collateral arteries. Additional immunofluorescence and histological stains were conducted to assess immune cell recruitment and activation. Whole-blood flow cytometry was performed to analyze platelet–leukocyte interactions, and complete blood counts were obtained to quantify leukocyte and platelet numbers. Results: The findings of this study demonstrate that Clopidogrel promotes perfusion recovery following the induction of arteriogenesis compared to controls, attributed to elevated levels of proliferating vascular cells. Furthermore, compared to controls, Clopidogrel treatment significantly enhanced platelet-leukocyte interactions, increasing perivascular mast cell recruitment and degranulation, finally resulting in regenerative macrophage accumulation required for collateral artery growth. Conclusions: Clopidogrel treatment boosts arteriogenesis by enhancing the local regenerative inflammation relevant for vascular cell proliferation. Therefore, P2Y₁₂ inhibition may represent a therapeutic option to effectively promote natural bypass growth in patients with cardiovascular occlusive diseases. Full article

Introduction: Among aortic diseases in children, congenital defects such as coarctation of the aorta (CoA), interrupted aortic arch (IAA), hypoplastic aortic arch (HAA), and hypoplastic left heart syndrome (HLHS) predominate. Tissue patches are applied in pediatric cardiovascular surgery for the repair of congenital aortic defects as a filling material to replenish missing tissue or as a substitute material for the complete reconstruction of the vascular wall along the course of the vessel. This retrospective single-center study aimed to present the safety and feasibility of extracellular matrix (ECM) biological scaffolds in pediatric aortic surgery. Patients and methods: There were 26 patients (17 newborns and nine children), who underwent surgical procedures in the Department of Pediatric Cardiac Surgery (Poznań, Poland) between 2023 and 2024. The patients’ population was divided into two subgroups according to the hemodynamic nature of the primary diagnosis of the congenital heart defect and the performed pediatric cardiovascular surgery. The first group included 18 (72%) patients after aortic arch repair for interrupted aortic arch and/or hypoplastic aortic arch, while the second group included seven (28%) patients after aortopulmonary anastomosis. In the first group, patches were used to reconstruct the aortic arch by forming an artificial arch with three separate patches sewn together, primarily addressing the hypoplastic or interrupted segments. In the second group, patches were applied to augment the anastomosis site between the pulmonary trunk and the aortic arch, specifically at the connection points in procedures, such as the Damus–Kaye–Stansel or Norwood procedures. The analysis was based on data acquired from the national cardiac surgery registry. Results: The overall mortality in the presented group was 15%. All procedures were performed using median sternotomy with a cardiopulmonary bypass. The cardiopulmonary bypass (CPB) and aortic cross-clamp (AoX) median times were 144 (107–176) and 53 (33–79) min, respectively. There were two (8%) cases performed in deep hypothermic circulatory arrest (DHCA). The median postoperative stay in the intensive care unit (ICU) was 284 (208–542) h. The median mechanical ventilation time was 226 (103–344) h, including 31% requiring prolonged mechanical ventilation support. Postoperative acute kidney failure requiring hemodiafiltration (HDF) was noticed in 12% of cases. Follow-up data, collected via routine transthoracic echocardiography (TTE) and clinical assessments over a median of 418 (242.3–596.3) days, showed no evidence of patch-related complications such as restenosis, aneurysmal dilation, or calcification in surviving patients. One patient required reintervention on the same day due to a significantly narrow ascending aorta, unrelated to patch failure. No histological data from explanted patches were available, as no patches were removed during the study period. The median (Q1–Q3) hospitalization time was 21 (16–43) days. Conclusions: ProxiCor^® biological patches derived from the extracellular matrix can be safely used in pediatric patients with congenital aortic arch disease. Long-term follow-up is necessary to confirm the durability and growth potential of these patches, particularly regarding their resistance to calcification and dilation. Full article

Magnetorheological (MR) brakes are flourishing in low-torque applications due to their dynamic controllability nature. Researchers have introduced multi-layer and multipole concepts to increase the torque–volume ratio (TVR) of the MR brake. However, the combination of these two ideas did not exist due to the design limitations. Therefore, this study aims to design a brake that combines the multipole magnetic field and multi-layered structure concepts. The axial slots were introduced on the brake rotor and the stator drum axial surfaces to achieve a high TVR. These slots stop the flux bypass in the inner layers; therefore, the magnetic flux can also reach the brake’s outer layers. This brake was designed with multiple stator and rotor drums and MR fluid layers. The number of poles was placed so that the magnetic field from these poles traveled in a closed loop via the stator, rotor, and MR layers. A 3D model of the brake was prepared for the virtual study. Electromagnetic simulations were conducted to analyze the effect of axial slots’ and other design parameters of the brake. According to those simulation results, the axial slots’ width and position significantly affect the brake output torque. The maximum torque obtained from the brake is 38 Nm, and the TVR value of the brake is 41 Nm/dm³. Additionally, multiphysics simulations were performed to understand the Joule-heating effect of the magnetic coil and the frictional heating in MR fluid. Results showed that the maximum possible temperature in the brake is under the MR fluid temperature limits. Therefore, this multipole multi-layered (MPML) MR brake with axial slots idea is very useful for high-torque MR brake growth. Full article

Arteriogenesis is an inflammatory driven mechanism, describing the growth of a natural bypass from pre-existing collateral arteries to compensate for an occluded artery. The complement system component C3 is a potent natural inflammatory activator. Here, we investigated its impact on the process of collateral artery growth using C3-deficient (C3 −/−) and wildtype control mice in a murine hindlimb model of arteriogenesis. Induction of arteriogenesis by unilateral femoral artery ligation resulted in decreased perfusion recovery in C3 −/− mice on day 7 as shown by Laser Doppler imaging. Immunofluorescence staining revealed a reduced vascular cell proliferation in C3 −/− mice. Gene expression analysis displayed a significant reduction in monocyte chemoattractant protein-1 (MCP-1) expression in C3 −/− mice. Interestingly, 3 days after induction of arteriogenesis, the number of macrophages (CD68⁺) recruited to growing collaterals was not affected by C3 deficiency. However, a significant reduction in inflammatory M1-like polarized macrophages (CD68⁺/MRC1⁻) was noted. Forced mast cell activation by Compound 48/80 as well as exogenous MCP-1 application rescued the number of M1-like polarized macrophages along with perfusion recovery in C3 −/− mice. In summary, this study demonstrates that complement C3 influences arteriogenesis by mediating MCP-1 expression, which is essential for the induction and enhancement of sterile inflammation. Full article

The repurposing of previously clinically approved drugs as an alternative therapeutic approach to treating disease has gained significant attention in recent years. A multitude of studies have demonstrated various and successful therapeutic interventions with these drugs in a wide range of neoplastic diseases, including multiple myeloma, leukaemia, glioblastoma, and colon cancer. Drug repurposing has been widely encouraged due to the known efficacy, safety, and convenience of already established drugs, allowing the bypass of the long and difficult road of lead optimization and drug development. Repurposing drugs in cancer therapy is an exciting prospect due to the ability of these drugs to successfully target cancer-associated genes, often dysregulated in oncogenic signalling pathways, amongst which are the classical cancer signalling pathways; WNT (wingless-related integration type) and Hippo signalling. These pathways play a fundamental role in controlling organ size, tissue homeostasis, cell proliferation, and apoptosis, all hallmarks of cancer initiation and progression. Prolonged dysregulation of these pathways has been found to promote uncontrolled cellular growth and malignant transformation, contributing to carcinogenesis and ultimately leading to malignancy. However, the translation of cancer signalling pathways and potential targeted therapies in cancer treatment faces ongoing challenges due to the pleiotropic nature of cancer cells, contributing to resistance and an increased rate of incomplete remission in patients. This review provides analyses of a range of potential anti-cancer compounds in drug repurposing. It unravels the current understanding of the molecular rationale for repurposing these drugs and their potential for targeting key oncogenic signalling pathways. Full article

Cancer is defined as the uncontrolled proliferation of heterogeneous cell cultures in the body that develop abnormalities and mutations, leading to their resistance to many forms of treatment. Left untreated, these abnormal cell growths can lead to detrimental and even fatal complications for patients. Radiation therapy is involved in around 50% of cancer treatment workflows; however, it presents significant recurrence rates and normal tissue toxicity, given the inevitable deposition of the dose to the surrounding healthy tissue. Chemotherapy is another treatment modality with excessive normal tissue toxicity that significantly affects patients’ quality of life. To improve the therapeutic efficacy of radiotherapy and chemotherapy, multiple conjunctive modalities have been proposed, which include the targeting of components of the tumour microenvironment inhibiting tumour spread and anti-therapeutic pathways, increasing the oxygen content within the tumour to revert the hypoxic nature of the malignancy, improving the local dose deposition with metal nanoparticles, and the restriction of the cell cycle within radiosensitive phases. The tumour microenvironment is largely responsible for inhibiting nanoparticle capture within the tumour itself and improving resistance to various forms of cancer therapy. In this review, we discuss the current literature surrounding the administration of molecular and nanoparticle therapeutics, their pharmacokinetics, and contrasting mechanisms of action. The review aims to demonstrate the advancements in the field of conjugated nanomaterials and radiotherapeutics targeting, inhibiting, or bypassing the tumour microenvironment to promote further research that can improve treatment outcomes and toxicity rates. Full article

Increasing evidence suggests that lymphocytes play distinct roles in inflammation-induced tissue remodeling and tissue damage. Arteriogenesis describes the growth of natural bypasses from pre-existing collateral arteries. This process compensates for the loss of artery function in occlusive arterial diseases. The role of innate immune cells is widely understood in the process of arteriogenesis, whereas the role of lymphocytes remains unclear and is the subject of the present study. To analyze the role of lymphocytes, we induced arteriogenesis in recombination activating gene-1 (Rag1) knockout (KO) mice by unilateral ligation of the femoral artery. The lack of functional lymphocytes in Rag1 KO mice resulted in reduced perfusion recovery as shown by laser Doppler imaging. Additionally, immunofluorescence staining revealed a reduced vascular cell proliferation along with a smaller inner luminal diameter in Rag1 KO mice. The perivascular macrophage polarization around the growing collateral arteries was shifted to more pro-inflammatory M1-like polarized macrophages. Together, these data suggest that lymphocytes are crucial for arteriogenesis by modulating perivascular macrophage polarization. Full article

Increasing CO₂ levels in the atmosphere and the resulting negative impacts of climate change have compelled global efforts to achieve carbon neutrality or negativity. Most such efforts focus on carbon sequestration through chemical or physical approaches. Harnessing the power of synthetic biology to enhance the natural ability of carbon sequestration in plants, especially non-annuals, provides a biological approach to further reduce CO₂ levels in the air. Here, we selected a photorespiration bypass pathway and tested its effectiveness on photosynthetic enhancement in a hybrid poplar, INRA717-IB4. The design includes an RNAi strategy to reduce the transportation of the photorespiration byproduct, glycolate, out of chloroplast and a shunt pathway to metabolize the retained glycolate back to CO₂ for fixation through the Calvin-Benson cycle. Molecular and physiological data collected from two separate growth experiments indicate that transgenic plants expressing genes in the photorespiration bypass pathway have increased photosynthetic efficiency, leading to faster plant growth and elevated biomass production. One lead transgenic event accumulated 35%–53% more above-ground dry biomass over four months of growth in a controlled environment. Our results provide a proof of concept for engineering trees to help combat climate change. Full article

Cancer drug resistance remains a major obstacle in clinical oncology. As most anticancer drugs are of natural origin, we investigated the anticancer potential of a standardized cold-water leaf extract from Nerium oleander L., termed Breastin. The phytochemical characterization by nuclear magnetic resonance spectroscopy (NMR) and low- and high-resolution mass spectrometry revealed several monoglycosidic cardenolides as major constituents (adynerin, neritaloside, odoroside A, odoroside H, oleandrin, and vanderoside). Breastin inhibited the growth of 14 cell lines from hematopoietic tumors and 5 of 6 carcinomas. Remarkably, the cellular responsiveness of odoroside H and neritaloside was not correlated with all other classical drug resistance mechanisms, i.e., ATP-binding cassette transporters (ABCB1, ABCB5, ABCC1, ABCG2), oncogenes (EGFR, RAS), tumor suppressors (TP53, WT1), and others (GSTP1, HSP90, proliferation rate), in 59 tumor cell lines of the National Cancer Institute (NCI, USA), indicating that Breastin may indeed bypass drug resistance. COMPARE analyses with 153 anticancer agents in 74 tumor cell lines of the Oncotest panel revealed frequent correlations of Breastin with mitosis-inhibiting drugs. Using tubulin-GFP-transfected U2OS cells and confocal microscopy, it was found that the microtubule-disturbing effect of Breastin was comparable to that of the tubulin-depolymerizing drug paclitaxel. This result was verified by a tubulin polymerization assay in vitro and molecular docking in silico. Proteome profiling of 3171 proteins in the NCI panel revealed protein subsets whose expression significantly correlated with cellular responsiveness to odoroside H and neritaloside, indicating that protein expression profiles can be identified to predict the sensitivity or resistance of tumor cells to Breastin constituents. Breastin moderately inhibited breast cancer xenograft tumors in vivo. Remarkably, in contrast to what was observed with paclitaxel monotherapy, the combination of paclitaxel and Breastin prevented tumor relapse, indicating Breastin’s potential for drug combination regimens. Full article

Many clinical trials have attempted to use stem cells to treat ischemic heart diseases (IHD), but the benefits have been modest. Though coronary collaterals can be a “natural bypass” for IHD patients, the regulation of coronary collateral growth (CCG) and the role of endogenous stem cells in CCG are not fully understood. In this study, we used a bone marrow transplantation scheme to study the role of bone marrow stem cells (BMSCs) in a rat model of CCG. Transgenic GFP rats were used to trace BMSCs after transplantation; GFP bone marrow was harvested or sorted for bone marrow transplantation. After recovering from transplantation, the recipient rats underwent 10 days of repetitive ischemia (RI), with echocardiography before and after RI, to measure cardiac function and myocardial blood flow. At the end of RI, the rats were sacrificed for the collection of bone marrow for flow cytometry or heart tissue for imaging analysis. Our study shows that upon RI stimulation, BMSCs homed to the recipient rat hearts’ collateral-dependent zone (CZ), proliferated, differentiated into endothelial cells, and engrafted in the vascular wall for collateral growth. These RI-induced collaterals improved coronary blood flow and cardiac function in the recipients’ hearts during ischemia. Depletion of donor CD34⁺ BMSCs led to impaired CCG in the recipient rats, indicating that this cell population is essential to the process. Overall, these results show that BMSCs contribute to CCG and suggest that regulation of the function of BMSCs to promote CCG might be a potential therapeutic approach for IHD. Full article

Ocular GVHD (oGVHD), manifested by severe injury of corneal epithelial cells, meibomian and lacrimal glands’ dysfunction, is a serious complication of systemic GVHD which develops as a consequence of donor T and natural killer cell-driven inflammation in the eyes of patients who received allogeneic hematopoietic stem cell transplantation. Mesenchymal stem cells (MSC) are, due to their enormous differentiation potential and immunosuppressive characteristics, considered as a potentially new remedy in ophthalmology. MSC differentiate in corneal epithelial cells, suppress eye inflammation, and restore meibomian and lacrimal glands’ function in oGVHD patients. MSC-sourced exosomes (MSC-Exos) are extracellular vesicles that contain MSC-derived growth factors and immunoregulatory proteins. Due to the lipid membrane and nano-sized dimension, MSC-Exos easily by-pass all biological barriers in the eyes and deliver their cargo directly in injured corneal epithelial cells and eye-infiltrated leukocytes, modulating their viability and function. As cell-free agents, MSC-Exos address all safety issues related to the transplantation of their parental cells, including the risk of unwanted differentiation and aggravation of intraocular inflammation. In this review article, we summarized current knowledge about molecular mechanisms which are responsible for beneficial effects of MSC and MSC-Exos in the therapy of inflammatory eye diseases, emphasizing their therapeutic potential in the treatment of oGVHD. Full article

Arteriogenesis, the growth of natural bypass blood vessels, can compensate for the loss of arteries caused by vascular occlusive diseases. Accordingly, it is a major goal to identify the drugs promoting this innate immune system-driven process in patients aiming to save their tissues and life. Here, we studied the impact of the Cobra venom factor (CVF), which is a C3-like complement-activating protein that induces depletion of the complement in the circulation in a murine hind limb model of arteriogenesis. Arteriogenesis was induced in C57BL/6J mice by femoral artery ligation (FAL). The administration of a single dose of CVF (12.5 µg) 24 h prior to FAL significantly enhanced the perfusion recovery 7 days after FAL, as shown by Laser Doppler imaging. Immunofluorescence analyses demonstrated an elevated number of proliferating (BrdU⁺) vascular cells, along with an increased luminal diameter of the grown collateral vessels. Flow cytometric analyses of the blood samples isolated 3 h after FAL revealed an elevated number of neutrophils and platelet-neutrophil aggregates. Giemsa stains displayed augmented mast cell recruitment and activation in the perivascular space of the growing collaterals 8 h after FAL. Seven days after FAL, we found more CD68⁺/MRC-1⁺ M2-like polarized pro-arteriogenic macrophages around growing collaterals. These data indicate that a single dose of CVF boosts arteriogenesis by catalyzing the innate immune reactions, relevant for collateral vessel growth. Full article

Arterial stenosis or blockage is the leading cause of cardiovascular disease, and the common solution is to substitute the arteries by autologous veins or bypass the blood vessels physically. With the development of science and technology, arteries with diameter larger than 6 mm can be substituted by unbiodegradable polymers, such as polytetrafluoroethylene, clinically. Nevertheless, the construction of a small-diameter (less than 6 mm) artery with living cells has always been a thorny problem. In this study, a suit of combined mold was designed and forged for constructing small-diameter arterial vessels. Based on this combined mold, bioactive arterial vessels containing adipose-derived stem cells (ASCs) and different growth factors (GFs) were assembled together to mimic the inner and middle layers of the natural arteries. Before assembling, ASCs and GFs were loaded into a gelatin/alginate hydrogel. To enhance the mechanical property of the bilayer arterial vessels, polylactic–glycolic acid (PLGA) was applied on the surface of the bilayer vessels to form the outer third layer. The biocompatibility, morphology and mechanical property of the constructed triple-layer arterial vessels were characterized. The morphological results manifested that cells grow well in the gelatin/alginate hydrogels, and ASCs were differentiated into endothelial cells (ECs) and smooth muscle cells (SMCs), respectively. In addition, under the action of shear stress produced by the flow of the culture medium, cells in the hydrogels with high density were connected to each other, similar to the natural vascular endothelial tissues (i.e., endothelia). Especially, the mechanical property of the triple-layer arterial vessels can well meet the anti-stress requirements as human blood vessels. In a word, a small-diameter arterial vessel was successfully constructed through the combined mold and has a promising application prospect as a clinical small-diameter vessel graft. Full article