VEGF and bFGF induction by nitric oxide is associated with hyperbaric oxygen-induced angiogenesis and muscle regeneration

Multiplexed PLGA scaffolds with nitric oxide-releasing zinc oxide and melatonin-modulated extracellular vesicles for severe chronic kidney disease

INTRODUCTION

With prevalence of chronic kidney disease (CKD) in worldwide, the strategies to recover renal function via tissue regeneration could provide alternatives to kidney replacement therapies. However, due to relatively low reproducibility of renal basal cells and limited bioactivities of implanted biomaterials along with the high probability of substance-inducible inflammation and immunogenicity, kidney tissue regeneration could be challenging.

OBJECTIVES

To exclude various side effects from cell transplantations, in this study, we have induced extracellular vesicles (EVs) incorporated cell-free hybrid PMEZ scaffolds.

METHODS

Hybrid PMEZ scaffolds incorporating essential bioactive components, such as ricinoleic acid grafted Mg(OH)2 (M), extracellular matrix (E), and alpha lipoic acid-conjugated ZnO (Z) based on biodegradable porous PLGA (P) platform was successfully manufactured. Consecutively, for functional improvements, melatonin-modulated extracellular vesicles (mEVs), derived from the human umbilical cord MSCs in chemically defined media without serum impurities, were also loaded onto PMEZ scaffolds to construct the multiplexed PMEZ/mEV scaffold.

RESULTS

With functionalities of Mg(OH)2 and extracellular matrix-loaded PLGA scaffolds, the continuous nitric oxide-releasing property of modified ZnO and remarkably upregulated regenerative functionalities of mEVs showed significantly enhanced kidney regenerative activities. Based on these, the structural and functional restoration has been practically achieved in 5/6 nephrectomy mouse models that mimicked severe human CKD.

CONCLUSION

Our study has proved the combinatory bioactivities of the biodegradable PLGA-based multiplexed scaffold for kidney tissue regeneration in 5/6 nephrectomy mouse representing a severe CKD model. The optimal microenvironments for the morphogenetic formations of renal tissues and functional restorations have successfully achieved the combinatory bioactivities of remarkable components for PMEZ/mEV, which could be a promising therapeutic alternative for CKD treatment.

Crosstalk Between H-Type Vascular Endothelial Cells and Macrophages: A Potential Regulator of Bone Homeostasis

The crosstalk between H-type endothelial cells (ECs) and macrophages is critical for maintaining angiogenesis and osteogenesis in bone homeostasis. As core components of type H vessels, ECs respond to various pro-angiogenic signals, forming specialized vascular structures characterized by high expression of platelet-endothelial cell adhesion molecule-1 (CD31) and endothelial mucin (EMCN), thereby facilitating angiogenesis-osteogenesis coupling during bone formation. Macrophages, as key immune cells in the perivascular region, are primarily classified into the classically activated pro-inflammatory M1 phenotype and the selectively activated anti-inflammatory M2 phenotype, thereby performing dual functions in regulating local tissue homeostasis and innate immunity. In recent years, the complex crosstalk between type H vessel ECs and macrophages has garnered significant interest in the context of bone-related diseases. Orderly regulation of angiogenesis and bone immunity provides a new direction for preventing bone metabolic disorders such as osteoporosis and osteoarthritis. However, their interactions in bone homeostasis remain insufficiently understood, with limited clinical data available. This review comprehensively examines the intricate interactions between type H vessel ECs and macrophages with diverse phenotypes, and Insights into the signaling pathways that regulate their crosstalk, focusing on their roles in angiogenesis and osteogenesis. Furthermore, the review discusses recent interventions targeting this crosstalk and the challenges that remain. These insights may offer new perspectives on bone homeostasis and provide a theoretical foundation for developing novel therapeutic strategies.

L-Arginine and Nitric Oxide in Vascular Regulation-Experimental Findings in the Context of Blood Donation

This narrative review provides an analysis of the role of nitric oxide (NO) and its precursors, particularly L-arginine, in vascular regulation and health, with an emphasis on findings from our experimental research in animal models. NO serves as a critical mediator of vascular function, contributing to vasodilation, the regulation of blood flow, and the prevention of thrombosis. As a primary precursor of NO, L-arginine is essential for maintaining endothelial integrity, modulating mitochondrial function, and reducing oxidative damage. This review synthesises the data and contextualises these findings within the physiological challenges faced by blood donors, such as repeated blood donation and associated oxidative stress. It examines the effects of L-arginine supplementation on mitochondrial respiration, lipid peroxidation, and microsomal oxidation in different conditions, including differences in age, gender, and dietary interventions. The mechanisms by which L-arginine enhances NO production, improves vascular elasticity, and alleviates endothelial dysfunction caused by reduced NO bioavailability are also investigated. By integrating experimental findings with insights from the existing literature, this review provides a perspective on the potential of L-arginine supplementation to address the specific physiological needs of blood donors. It highlights the importance of personalised nutritional approaches in enhancing donor recovery and vascular resilience. In addition, this review assesses the wider implications of L-arginine supplementation in mitigating oxidative stress and preserving vascular function. The interplay between NO bioavailability, dietary factors, and physiological adaptation in blood donors is highlighted, along with the identification of current knowledge gaps and recommendations for future research. By presenting both original experimental evidence and a critical synthesis of the literature, this article highlights the therapeutic potential of NO precursors, particularly L-arginine, in promoting vascular health in the context of blood donation.

Advanced dressings based on novel biological targets for diabetic wound healing: A review

The diabetic wound is one of the most common complications of diabetes in clinic. The existing diabetic wound dressings all have bottlenecks in decreasing inflammation, stopping peripheral neuropathy, relieving local ischemia and hypoxia in diabetic wounds. These challenges are intricately linked to the roles of various growth factors, as well as matrix metalloproteinases. Thus, a comprehensive understanding of growth factors-particularly their dynamic interactions with the extracellular matrix (ECM) and cellular components-is essential. Cells and proteins that influence the synthesis of growth factors and matrix metalloproteinases emerge as potential therapeutic targets for diabetic wound management. This review discusses the latest advancements in the pathophysiology of diabetic wound healing, highlights novel biological targets, and evaluates new wound dressing strategies designed for the treatment of diabetic wounds.

Engineering large-scale hiPSC-derived vessel-integrated muscle-like lattices for enhanced volumetric muscle regeneration

Engineering biomimetic tissue implants with human induced pluripotent stem cells (hiPSCs) holds promise for repairing volumetric tissue loss. However, these implants face challenges in regenerative capability, survival, and geometric scalability at large-scale injury sites. Here, we present scalable vessel-integrated muscle-like lattices (VMLs), containing dense and aligned hiPSC-derived myofibers alongside passively perfusable vessel-like microchannels inside an endomysium-like supporting matrix using an embedded multimaterial bioprinting technology. The contractile and millimeter-long myofibers are created in mechanically tailored and nanofibrous extracellular matrix-based hydrogels. Incorporating vessel-like lattice enhances myofiber maturation in vitro and guides host vessel invasion in vivo, improving implant integration. Consequently, we demonstrate successful de novo muscle formation and muscle function restoration through a combinatorial effect between improved graft-host integration and its increased release of paracrine factors within volumetric muscle loss injury models. The proposed modular bioprinting technology enables scaling up to centimeter-sized prevascularized hiPSC-derived muscle tissues with custom geometries for next-generation muscle regenerative therapies.

Effects of diet-induced metabolic syndrome on cardiac function and angiogenesis in response to the sodium-glucose cotransporter-2 inhibitor canagliflozin

INTRODUCTION

Sodium-glucose cotransporter-2 inhibitors are antidiabetic medications that have been shown to decrease cardiovascular events and heart failure-related mortality in clinical studies. We attempt to examine the complex interplay between metabolic syndrome and the sodium-glucose cotransporter-2 inhibitor canagliflozin (CAN) in a clinically relevant model of chronic myocardial ischemia.

METHODS

Twenty-one Yorkshire swine were fed a high-fat diet starting at 6 weeks of age to induce metabolic syndrome. At 11 weeks, all underwent placement of an ameroid constrictor around the left circumflex coronary artery to induce chronic myocardial ischemia. After 2 weeks, swine received either control (CON) (n = 11) or CAN 300 mg by mouth daily (n = 10) for 5 weeks, whereupon all underwent terminal harvest.

RESULTS

There was a significant increase in cardiac output and heart rate with a decrease in pulse pressure in the CAN group compared with CON (all P values < .05). The CAN group had a significant increase in capillary density (P = .02). There was no change in myocardial perfusion or arteriolar density. CAN induced a significant increase in markers of angiogenesis, including Phospho-endothelial nitric oxide synthase, Endothelial nitric oxide synthase, vascular endothelial growth factor receptor-1, heat shock protein 70, and extracellular signal-regulated kinases (all P values < .05), plausibly resulting in capillary angiogenesis.

CONCLUSIONS

CAN treatment leads to a significant increase in capillary density and augmented cardiac function in a swine model of chronic myocardial ischemia in the setting of metabolic syndrome. This work further elucidates the mechanism of sodium-glucose cotransporter-2 inhibitors in patients with cardiac disease; however, more studies are needed to determine if this increase in capillary density plays a role in the improvements seen in clinical studies.

Intravitreal Metformin Protects Against Choroidal Neovascularization and Light-Induced Retinal Degeneration

Neovascular age-related macular degeneration (nAMD), a leading cause of blindness in older adults, presents a challenging pathophysiology involving choroidal neovascularization (CNV) and retinal degeneration. Current treatments relying on intravitreal (IVT) administration of anti-angiogenic agents are costly and of moderate effectiveness. Metformin, the common anti-diabetic drug, has been associated with decreased odds of developing AMD. Studies have shown that metformin can mitigate cellular aging, neoangiogenesis, and inflammation across multiple diseases. This preclinical study assessed metformin's impact on vessel growth using choroidal explants before exploring IVT metformin's effects on laser-induced CNV and light-induced retinal degeneration in C57BL/6J and BALB/cJ mice, respectively. Metformin reduced new vessel growth in choroidal explants in a dose-dependent relationship. Following laser induction, IVT metformin suppressed CNV and decreased peripheral infiltration of IBA1+ macrophages/microglia. Furthermore, IVT metformin protected against retinal thinning in response to light-induced degeneration. IVT metformin downregulated genes in the choroid and retinal pigment epithelium which are associated with angiogenesis and inflammation, two key processes that drive nAMD progression. These findings underscore metformin's capacity as an anti-angiogenic and neuroprotective agent, demonstrating this drug's potential as an accessible option to help manage nAMD.

Vascular smooth muscle cell-derived exosomes promote osteoblast-to-osteocyte transition via β-catenin signaling

Blood vessel growth and osteogenesis in the skeletal system are coupled; however, fundamental aspects of vascular function in osteoblast-to-osteocyte transition remain unclear. Our study demonstrates that vascular smooth muscle cells (VSMCs), but not endothelial cells, are sufficient to drive bone marrow mesenchymal stromal cell-derived osteoblast-to-osteocyte transition via β-catenin signaling and exosome-mediated communication. We found that VSMC-derived exosomes are loaded with transcripts encoding proteins associated with the osteocyte phenotype and members of the WNT/β-catenin signaling pathway. In contrast, endothelial cell-derived exosomes facilitated mature osteoblast differentiation by reprogramming the TGFB1 gene family and osteogenic transcription factors osterix (SP7) and RUNX2. Notably, VSMCs express significant levels of tetraspanins (CD9, CD63, and CD81) and drive the intracellular trafficking of exosomes with a lower membrane zeta potential than those from other cells. Additionally, the high ATP content within these exosomes supports mineralization mechanisms, as ATP is a substrate for alkaline phosphatase. Osteocyte function was further validated by RNA sequencing, revealing activity in genes related to intermittent mineralization and sonic hedgehog signaling, alongside a significant increase in TNFSF11 levels. Our findings unveil a novel role of VSMCs in promoting osteoblast-to-osteocyte transition, thus offering new insights into bone biology and homeostasis, as well as in bone-related diseases. Clinically, these insights could pave the way for innovative therapeutic strategies targeting VSMC-derived exosome pathways to treat bone-related disorders such as osteoporosis. By manipulating these signaling pathways, it may be possible to enhance bone regeneration and improve skeletal health in patients with compromised bone structure and function.

Hyperbaric oxygen promotes bone regeneration by activating the mechanosensitive Piezo1 pathway in osteogenic progenitors

Background

Hyperbaric oxygen (HBO) therapy is widely used to treat bone defects, but the correlation of high oxygen concentration and pressure to osteogenesis is unclear.

Methods

Bilateral monocortical tibial defect surgeries were performed on 12-week-old Prrx1-Cre; Rosa26-tdTomato and Prrx1-Cre; Piezo1fl/+ mice. Daily HBO treatment was applied on post-surgery day (PSD) 1-9; and daily mechanical loading on tibia was from PSD 5 to 8. The mice were euthanized on PSD 10, and bone defect repair in their tibias was evaluated using μCT, biomechanical testing, and immunofluorescence deep-tissue imaging. The degree of angiogenesis-osteogenesis coupling was determined through spatial correlation analysis. Bone marrow stromal cells from knockout mice were cultured in vitro, and their osteogenic capacities of the cells were assessed. The activation of genes in the Piezo1-YAP pathway was evaluated using RNA sequencing and quantitative real-time polymerase chain reaction.

Results

Lineage tracing showed HBO therapy considerably altered the number of Prrx1+ cells and their progeny in a healing bone defect. Using conditional knockdown mice, we found that HBO stimulation activates the Piezo1-YAP axis in Prrx1+ cells and promotes osteogenesis-angiogenesis coupling during bone repair. The beneficial effect of HBO was similar to that of anabolic mechanical stimulation, which also acts through the Piezo1-YAP axis. Subsequent transcriptome sequencing results revealed that similar mechanosensitive pathways are activated by HBO therapy in a bone defect.

Conclusion

HBO therapy promotes bone tissue regeneration through the mechanosensitive Piezo1-YAP pathway in a population of Prrx1+ osteogenic progenitors. Our results contribute to the understanding of the mechanism by which HBO therapy treats bone defects.

The Translational Potential of this Article

Hyperbaric oxygen therapy is widely used in clinical settings. Our results show that osteogenesis was induced by the activation of the Piezo1-YAP pathway in osteoprogenitors after HBO stimulation, and the underlying mechanism was elucidated. These results may help improve current HBO methods and lead to the formulation of alternative treatments that achieve the same functional outcomes.

Transplantation of bioengineered dermal derived matrix-scaffold in combination with hyperbaric oxygen therapy improves wound healing in diabetic rats

Successful treatment of diabetic wounds requires multifactorial approaches. Herein we investigated the effects of a bioengineered three-dimensional dermal derived matrix-scaffold (DMS) in combination with hyperbaric oxygen (HBO) in repairing of wound model in diabetic rats. Thirty days after induction of diabetes, a circular wound was created and treatments were performed for 21 days. Animals were randomly allocated into the untreated group, DMS group, HBO group, and DMS+HBO group. On days 7, 14, and 21, tissue samples were obtained for stereological, molecular, and tensiometrical assessments. Our results showed that the wound closure rate, volume of new dermis and epidermis, numerical density fibroblasts and blood vessels, collagen density, and biomechanical characterize were significantly higher in the treatment groups than in the untreated group, and these changes were more obvious in the DMS+HBO ones. Moreover, the expression of TGF-β, bFGF, miRNA-21, miRNA-146a, and VEGF genes were meaningfully upregulated in treatment groups compared to the untreated group and were greater in the DMS+HBO group. This is while expression of TNF-α and IL-1β, as well as the numerical density of neutrophil and macrophage decreased more considerably in the DMS+HBO group than in the other groups. Overall, using both DMS engraftment and HBO treatment has more effects on diabetic wound healing.

Unveiling the significance of inducible nitric oxide synthase: Its impact on cancer progression and clinical implications

The intricate role of inducible nitric oxide synthase (iNOS) in cancer pathophysiology has garnered significant attention, highlighting the complex interplay between tumorigenesis, immune response, and cellular metabolism. As an enzyme responsible for producing nitric oxide (NO) in response to inflammatory stimuli. iNOS is implicated in various aspects of cancer development, including DNA damage, angiogenesis, and evasion of apoptosis. This review synthesizes the current findings from both preclinical and clinical studies on iNOS across different cancer types, reflecting the variability depending on cellular context and tumor microenvironment. We explore the molecular mechanisms by which iNOS modulates cancer cell growth, survival, and metastasis, emphasizing its impact on immune surveillance and response to treatment. Additionally, the potential of targeting iNOS as a therapeutic strategy in cancer treatment is examined. By integrating insights from recent advances, this review aims to elucidate the significant role of iNOS in cancer and pave the way for novel diagnostic and therapeutic approaches.

Redox signaling and skeletal muscle adaptation during aerobic exercise

Redox regulation is a fundamental physiological phenomenon related to oxygen-dependent metabolism, and skeletal muscle is mainly regarded as a primary site for oxidative phosphorylation. Several studies have revealed the importance of reactive oxygen and nitrogen species (RONS) in the signaling process relating to muscle adaptation during exercise. To date, improving knowledge of redox signaling in modulating exercise adaptation has been the subject of comprehensive work and scientific inquiry. The primary aim of this review is to elucidate the molecular and biochemical pathways aligned to RONS as activators of skeletal muscle adaptation and to further identify the interconnecting mechanisms controlling redox balance. We also discuss the RONS-mediated pathways during the muscle adaptive process, including mitochondrial biogenesis, muscle remodeling, vascular angiogenesis, neuron regeneration, and the role of exogenous antioxidants.

Retention of Improved Plantar Sensation in Patients with Type II Diabetes Mellitus and Sensory Peripheral Neuropathy after One Month of Vibrating Insole Therapy: A Pilot Study

Sensory peripheral neuropathy is a common complication of diabetes mellitus and the biggest risk factor for diabetic foot ulcers. There is currently no available treatment that can reverse sensory loss in the diabetic population. The application of mechanical noise has been shown to improve vibration perception threshold or plantar sensation (through stochastic resonance) in the short term, but the therapeutic use, and longer-term effects have not been explored. In this study, vibrating insoles were therapeutically used by 22 participants, for 30 min per day, on a daily basis, for a month by persons with diabetic sensory peripheral neuropathy. The therapeutic application of vibrating insoles in this cohort significantly improved VPT by an average of 8.5 V (p = 0.001) post-intervention and 8.2 V (p < 0.001) post-washout. This statistically and clinically relevant improvement can play a role in protection against diabetic foot ulcers and the delay of subsequent lower-extremity amputation.

Hyperoxia and brain: the link between necessity and injury from a molecular perspective

Oxygen (O2) supplementation is commonly used to treat hypoxia in patients with respiratory failure. However, indiscriminate use can lead to hyperoxia, a condition detrimental to living tissues, particularly the brain. The brain is sensitive to reactive oxygen species (ROS) and inflammation caused by high concentrations of O2, which can result in brain damage and mitochondrial dysfunction, common features of neurodegenerative disorders. Hyperoxia leads to increased production of ROS, causing oxidative stress, an imbalance between oxidants and antioxidants, which can damage tissues. The brain is particularly vulnerable to oxidative stress due to its lipid composition, high O2 consumption rate, and low levels of antioxidant enzymes. Moreover, hyperoxia can cause vasoconstriction and decreased O2 supply to the brain, posing a challenge to redox balance and neurodegenerative processes. Studies have shown that the severity of hyperoxia-induced brain damage varies with inspired O2 concentration and duration of exposure. Therefore, careful evaluation of the balance between benefits and risks of O2 supplementation, especially in clinical settings, is crucial.

Co-release of nitric oxide and L-arginine from poly (β-amino ester)-based adhesive reprogram macrophages for accelerated wound healing and angiogenesis in vitro and in vivo

Recently, insufficient angiogenesis and prolonged inflammation are crucial challenges of chronic skin wound healing. The sustained release of L-Arginine (L-Arg) and nitric oxide (NO) production can control immune responses, improve angiogenesis, enhance re-epithelialization, and accelerate wound healing. Here, we aim to improve wound healing via the controlled release of NO and L-Arg from poly (β-amino ester) (PβAE). In this regard, PβAE is functionalized with methacrylate poly-L-Arg (PAMA), and the role of PAMA content (50, 66, and 75 wt%) on the adhesive properties, L-Arg, and NO release, as well as collagen deposition, inflammatory responses, and angiogenesis, is investigated in vitro and in vivo. Results show that the PAMA/ PβAE could provide suitable adhesive strength (~25 kPa) for wound healing application. In addition, increasing the PAMA content from 50 to 75 wt% results in an increased release of L-Arg (approximately 1.4-1.7 times) and enhanced NO production (approximately 2 times), promoting skin cell proliferation and migration. The in vitro studies also show that compared to PβAE hydrogel, incorporation of 66 wt% PAMA (PAMA 66 sample) reveals superior collagen I synthesis (~ 3-4 times) of fibroblasts, controlled pro-inflammatory and improved anti-inflammatory cytokines secretion of macrophages, and accelerated angiogenesis (~1.5-2 times). In vivo studies in a rat model with a full-thickness skin defect also demonstrate the PAMA66 sample could accelerate wound healing (~98 %) and angiogenesis, compared to control (untreated wound) and Tegaderm™ commercial wound dressing. In summary, the engineered multifunctional PAMA functionalized PβAE hydrogel with desired NO and L-Arg release, and adhesive properties can potentially reprogram macrophages and accelerate skin healing for chronic wound healing.

Current Research, Industrialization Status, and Future Perspective of Cultured Meat

Expectations for the industrialization of cultured meat are growing due to the increasing support from various sectors, such as the food industry, animal welfare organizations, and consumers, particularly vegetarians, but the progress of industrialization is slower than initially reported. This review analyzes the main issues concerning the industrialization of cultured meat, examines research and media reports on the development of cultured meat to date, and presents the current technology, industrialization level, and prospects for cultured meat. Currently, over 30 countries have companies industrializing cultured meat, and around 200 companies that are developing or industrializing cultured meat have been surveyed globally. By country, the United States has over 50 companies, accounting for more than 20% of the total. Acquiring animal cells, developing cell lines, improving cell proliferation, improving the efficiency of cell differentiation and muscle production, or developing cell culture media, including serum-free media, are the major research themes related to the development of cultured meat. In contrast, the development of devices, such as bioreactors, which are crucial in enabling large-scale production, is relatively understudied, and few of the many companies invested in the development of cultured meat have presented products for sale other than prototypes. In addition, because most information on key technologies is not publicly available, it is not possible to determine the level of technology in the companies, and it is surmised that the technology of cultured meat-related startups is not high. Therefore, further research and development are needed to promote the full-scale industrialization of cultured meat.

P407 hydrogel loaded with nitric oxide microbubbles promotes angiogenesis and functional improvement in testicular transplantation

Prepubertal male patients with cancer have decreased fertility after treatment, but there are currently no suitable means for fertility rescue. Testicular transplantation seems to be a promising treatment. The short-term insufficiency of blood supply after transplantation is the key problem that needs to be solved. In this research, nitric oxide (NO), a gas and small molecule transmitter with the effect of promoting angiogenesis, acted at the site of testicular transplantation. Herein, poloxamer-407 (P407) and lipid microbubble materials served as transport carriers for NO and helped NO to function at the transplant site. P407 hydrogel loaded with NO microbubbles (PNO) slowly released NO in vitro. The three-dimensional space of the hydrogel provided a stable environment for NO microbubbles, which is conducive to the continuous release of NO. In this study, 25% PNO (w/v) was selected, and the gelling temperature was 19.47 °C. The gelling efficiency was relatively high at body temperature. Rheological experiments showed that PNO, at this concentration, had stable mechanical properties. The results from in vivo experiments demonstrated that testicular grafts in the PNO group exhibited a notably accelerated blood flow recovery compared to the other groups. Additionally, the PNO group displayed a significant improvement in reproductive function recovery. In conclusion, PNO exhibited slow release of NO, and a small amount of NO promoted angiogenesis in testicular grafts and restored reproductive function.

Nitric oxide releasing novel amino acid-derived polymeric nanotherapeutic with anti-inflammatory properties for rapid wound tissue regeneration

Endogenous gasotransmitter nitric oxide (NO) is a central signalling molecule that modulates wound healing by maintaining homeostasis, collagen formation, wound contraction, anti-microbial action and accelerating tissue regeneration. The optimum delivery of NO using nanoparticles (NPs) is clinically challenging; hence, it is drawing significant attention in wound healing. Herein, a novel polymeric nanoplatform loaded with sodium nitroprusside (SP) NPs was prepared and used for wound healing to obtain the sustained release of NO in therapeutic quantities. SP NPs-induced excellent proliferation (∼300%) of mouse fibroblast (L929) cells was observed. With an increase in the SP NPs dose at 200 μg mL-1 concentration, a 200% upsurge in proliferation was observed along with enhanced migration, and only 17.09 h were required to fill the 50% gap compared to 37.85 h required by the control group. Further, SP NPs showed an insignificant impact on the coagulation cascade, revealing safe wound-healing treatment when tested in isolated rat RBCs. Additionally, SP NPs exhibited excellent angiogenic activity at a 10 μg mL-1 dose. Moreover, the formulated SP nanoformulation is non-irritant, non-toxic, and does not produce any skin sensitivity reaction on the rat's skin. Further, an in vivo wound healing study revealed that within 11 days of treatment with SP nanoformulation, 99.2 ± 1.0% of the wound was closed, while in the control group, only 45.5 ± 3.8% was repaired. These results indicate that owing to sustained NO release, the SP NP and SP nanoformulations are paramount with enormous clinical potential for the regeneration of wound tissues.

Copper incorporated biomaterial-based technologies for multifunctional wound repair

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

Serous Retinal Detachment in a Patient With a Port-Wine Birthmark Associated With Prostaglandin Analog Therapy

An 11-year-old girl with a port-wine birthmark (PWB), diffuse choroid hemangioma (DCH), and glaucoma experienced decreased vision upon starting treatment with bimatoprost. The patient was switched to latanoprostene bunod. Her vision remained reduced. Shortly after, she was diagnosed with serous retinal detachment (SRD). Both SRD and vision improved following prostaglandin analog (PGA) cessation. Patients with PWB are likely to have DCH and glaucoma. DCH itself poses a risk factor for SRD. Certain glaucoma management modalities may further increase this risk. This report highlights the importance of regular surveillance for SRD in patients with DCH who are receiving PGA. [Ophthalmic Surg Lasers Imaging Retina 2023;54:723-729.].

Parathyroid Hormone Inhibits Fatty Infiltration and Muscle Atrophy After Rotator Cuff Tear by Browning of Fibroadipogenic Progenitors in a Rodent Model

BACKGROUND

Progressive fatty infiltration and muscle atrophy after rotator cuff tears lead to tendon repair failure and poor outcomes. Fibro-adipogenic progenitors (FAPs) are involved in fatty infiltration and muscle homeostasis of skeletal muscle. Inducing FAP differentiation into brown adipocyte-like "beige adipocytes" suppresses fatty infiltration and muscle atrophy.

HYPOTHESIS

Parathyroid hormone (PTH) suppresses fatty infiltration and muscle atrophy after rotator cuff tears in a rat model by browning of FAPs.

STUDY DESIGN

Controlled laboratory study.

METHODS

PTH was administered subcutaneously for 4 or 8 weeks to a rotator cuff tear model in rats. After treatment, fatty infiltration of supraspinatus muscles was assessed using Oil Red O staining and muscle atrophy using wet muscle weight and muscle fiber cross-sectional area. Costaining of platelet-derived growth factor receptor α (FAP marker) and uncoupling protein 1 (browning marker) was performed to confirm FAP browning by PTH. Mouse-isolated FAPs were cultured with PTH and evaluated for browning-related gene expression and adipogenic differentiation using BODIPY staining. Myogenic differentiation of C2C12 myoblasts was evaluated using coculture of PTH-treated browning FAPs with C2C12.

RESULTS

PTH inhibited fatty infiltration after rotator cuff tear at 8 weeks. Rotator cuff wet muscle loss of PTH-treated rats was inhibited at 4 and 8 weeks. Furthermore, PTH-treated rats demonstrated larger myofiber cross-sectional area than did untreated rats at 4 and 8 weeks. Costaining indicated colocalization of platelet-derived growth factor receptor α and uncoupling protein 1 and promoted PTH-induced FAP browning. PTH increased the expression of browning-related genes in FAPs and suppressed fat droplet accumulation in vitro. Coculture with PTH-treated FAPs promoted C2C12 cell differentiation into myotubes.

CONCLUSION

PTH induced FAP-derived beige adipocytes by upregulating browning-related gene expression, and the browning effect of PTH on FAPs inhibited fatty infiltration and muscle atrophy in the rat rotator cuff tear model. PTH might have potential as a therapeutic drug for fatty infiltration and muscle atrophy after rotator cuff tears.

CLINICAL RELEVANCE

PTH may expand treatment options for rotator cuff tears by reducing fatty infiltration and muscle atrophy after rotator cuff tears by browning of FAPs.

Cellular and molecular mechanisms in vascular repair after traumatic brain injury: a narrative review

Traumatic brain injury (TBI) disrupts normal brain function and is associated with high morbidity and fatality rates. TBI is characterized as mild, moderate or severe depending on its severity. The damage may be transient and limited to the dura matter, with only subtle changes in cerebral parenchyma, or life-threatening with obvious focal contusions, hematomas and edema. Blood vessels are often injured in TBI. Even in mild TBI, dysfunctional cerebral vascular repair may result in prolonged symptoms and poor outcomes. Various distinct types of cells participate in vascular repair after TBI. A better understanding of the cellular response and function in vascular repair can facilitate the development of new therapeutic strategies. In this review, we analyzed the mechanism of cerebrovascular impairment and the repercussions following various forms of TBI. We then discussed the role of distinct cell types in the repair of meningeal and parenchyma vasculature following TBI, including endothelial cells, endothelial progenitor cells, pericytes, glial cells (astrocytes and microglia), neurons, myeloid cells (macrophages and monocytes) and meningeal lymphatic endothelial cells. Finally, possible treatment techniques targeting these unique cell types for vascular repair after TBI are discussed.

Novel Metal Nanomaterials to Promote Angiogenesis in Tissue Regeneration

Angiogenesis-the formation of new blood vessels from existing blood vessels-has drawn significant attention in medical research. New techniques have been developed to control proangiogenic factors to obtain desired effects. Two important research areas are 1) understanding cellular mechanisms and signaling pathways involved in angiogenesis and 2) discovering new biomaterials and nanomaterials with proangiogenic effects. This paper reviews recent developments in controlling angiogenesis in the context of regenerative medicine and wound healing. We focus on novel proangiogenic materials that will advance the field of regenerative medicine. Specifically, we mainly focus on metal nanomaterials. We also discuss novel technologies developed to carry these proangiogenic inorganic molecules efficiently to target sites. We offer a comprehensive overview by combining existing knowledge regarding metal nanomaterials with novel developments that are still being refined to identify new nanomaterials.

Effects of the Foam Massage Roller on VEGF-A and FGF-2 Blood Levels in Young Men

BACKGROUND/AIM

Angiogenesis induced in muscles or massaged tissue is thought to support their regeneration and performance. Therefore, different methods that could promote angiogenesis are investigated. The aim of this study was to examine whether the use of the foam roller massager for lower limb muscles affects VEGF-A and FGF-2 levels in young men.

MATERIALS AND METHODS

The study group included 60 healthy young men attending Military University of Land Forces, Wroclaw, Poland. The participants were randomly divided into two groups. The experimental group included 40 individuals who performed self-massage of the lower limbs using a foam roller. The control group comprised 20 individuals who did not perform massage. Massage was applied to lower limb muscles four times a week for seven weeks. Blood was collected before the experiment and after weeks 1, 3, 5, and 7. ELISA was used to determine changes in VEGF-A and FGF-2 levels in blood serum.

RESULTS

The results of the study demonstrated a significant increase in VEGF-A serum levels in the group of individuals who underwent massage each week compared to VEGF-A concentrations before the experiment. The increase in VEGF-A levels in the experimental group was observed throughout the experiment compared to the control group. No significant changes in serum FGF-2 levels were found.

CONCLUSION

The use of a foam massage roller increased VEGF-A serum levels, which may indicate stimulation of angiogenesis.

The Mechanisms of Action of Hyperbaric Oxygen in Restoring Host Homeostasis during Sepsis

The perception of sepsis has shifted over time; however, it remains a leading cause of death worldwide. Sepsis is now recognized as an imbalance in host cellular functions triggered by the invading pathogens, both related to immune cells, endothelial function, glucose and oxygen metabolism, tissue repair and restoration. Many of these key mechanisms in sepsis are also targets of hyperbaric oxygen (HBO2) treatment. HBO2 treatment has been shown to improve survival in clinical studies on patients with necrotizing soft tissue infections as well as experimental sepsis models. High tissue oxygen tension during HBO2 treatment may affect oxidative phosphorylation in mitochondria. Oxygen is converted to energy, and, as a natural byproduct, reactive oxygen species are produced. Reactive oxygen species can act as mediators, and both these and the HBO2-mediated increase in oxygen supply have the potential to influence the cellular processes involved in sepsis. The pathophysiology of sepsis can be explained comprehensively through resistance and tolerance to infection. We argue that HBO2 treatment may protect the host from collateral tissue damage during resistance by reducing neutrophil extracellular traps, inhibiting neutrophil adhesion to vascular endothelium, reducing proinflammatory cytokines, and halting the Warburg effect, while also assisting the host in tolerance to infection by reducing iron-mediated injury and upregulating anti-inflammatory measures. Finally, we show how inflammation and oxygen-sensing pathways are connected on the cellular level in a self-reinforcing and detrimental manner in inflammatory conditions, and with support from a substantial body of studies from the literature, we conclude by demonstrating that HBO2 treatment can intervene to maintain homeostasis.

Combinative effects of β-elemene and propranolol on the proliferation, migration, and angiogenesis of hemangioma

Hemangioma (HA) is one of the most common benign vascular tumors among children. Propranolol is used as the first-line treatment for hemangioma and is a non-selective blocker of the β-adrenergic receptor. β-elemene is a compound extracted from Rhizoma zedoariae and has been approved for the treatment of tumors in clinical practice. However, the combinatorial effects of β-elemene and propranolol in the treatment of HA remains unclear. This study explored the combinative effects and mechanisms of β-elemene and propranolol using hemangioma-derived endothelial cells (HemECs). Cytotoxic assays showed that the combinatorial treatment of β-elemene and propranolol did not increase the cytotoxic effects of HemECs. Furthermore, functional analysis showed that the combinatorial treatment with β-elemene and propranolol significantly inhibited the proliferation, migration, and tube formation of the HemECs compared to the single treatment regimens. Mechanistic analysis showed that combinative treatment with β-elemene and propranolol synergistically down-regulated the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor-A (HIF-1-α/VEGFA) signaling pathway. Additionally, in a xenograft tumor model, angiogenesis in the combinatorial treatment group was significantly lower than in the control, propranolol, and β-elemene treatment alone groups. Our results suggest that β-elemene combined with propranolol can significantly inhibit the proliferation, migration, and tube formation of HemECs via synergistically down-regulating the HIF-1-α/VEGFA signaling pathway without increasing any cytotoxic side effects.

Potato Alkaloids α-Solanine and α-Chaconine Promote bFGF and VEGF Expression in Vein and Adjacent Tissues in the Rabbit Model of Phlebitis

Objectives:

To investigate the therapeutic effect of mashed potato and its alkaloids α-solanine and α-chaconine on basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) expression in ear venous vessels and adjacent tissues in a rabbit model of phlebitis.

Materials and Methods:

Japanese white rabbits were randomly allocated into control, vaseline cream (model), magnesium sulfate, mashed potato, α-solanine cream 100 mg/kg or 200 mg/kg, and α-chaconine cream 100 mg/kg or 200 mg/kg groups. The phlebitis model was established by intravenous infusion of vincristine in the rabbit ears. Group A received physiological saline. Group B−F was applied treatment 3 times/day, for 2 days along the ears vein. The alkaloid contents in α-solanine and α-chaconine were analyzed with HPLC. The bFGF, protein kinase C alpha (PKC-α), and VEGF expression in the ear vessels and nearby tissues were analyzed using immunohistochemistry, polymerase chain reaction (PCR), and Western blot analysis, respectively.

Results:

After phlebitis modeling, the vascular endothelium of the rabbit ear vein was damaged or layered, the lumen was swollen and deformed to an oval or round shape, and the proportion of bFGF and VEGF positive areas in the vascular endothelium and adjacent tissues was higher than the control group. The phlebitis score shows that various treatments have certain effects, among which magnesium sulfate wet gauze and mashed potatoes are more effective. The application of α-solanine and α-chaconine cream promotes the expression of bFGF and VEGF, as well as PKC-α in the venous blood vessels and adjacent tissues, but mashed potatoes had little effect.

Conclusion:

α-solanine and α-chaconine cream can promote the expression of bFGF and VEGF in venous blood vessels and adjacent tissues, which may contribute to the recovery of blood vessels in phlebitis.

Running exercise improves spatial learning and memory ability and enhances angiogenesis in the cerebral cortex via endogenous nitric oxide

BACKGROUND

The molecular mechanisms by which exercise improves brain function and capillaries in the cerebral cortex are unclear. Exercise can increase the expression of nitric oxide (NO) in the brain, and endogenous NO is thought to exert beneficial effects on proangiogenic factors, antiangiogenic factors and brain function. Therefore, we hypothesized that running exercise might improve brain function and enhance angiogenesis through endogenous NO.

METHODS AND RESULTS

The following three groups of rats were administered intracerebroventricular (i.c.v.) injections before running exercise each day for 4 weeks: exercise+L-NAME group (i.c.v. L-NAME, an NO synthase blocker, dose: 1 μmol/μl and 5 μl/day; treadmill exercise, 20 min/day), exercise group (i.c.v. normal saline, 5 μl/day; treadmill exercise, 20 min/day), and sham group (i.c.v. normal saline, 5 μl/day; no treadmill exercise). Subsequently, the spatial learning and memory abilities were tested using a Morris water maze, and the nitric oxide synthase (NOS) activity in the cerebral cortex in each group of rats was measured using a method involving nitric acid reductase and metabolic chemistry. The parameters of the cortical capillaries were quantitatively investigated using an immunohistochemistry technique and stereological methods. The expression levels of proangiogenic factors (VEGF and FGF-2) and an antiangiogenic inhibitor (endostatin) in the cerebral cortex were tested using a Western blot analysis. Running exercise significantly improved the rats' spatial learning and memory abilities and increased NOS activity in the cortex. Running exercise also subsequently improved the expression of proangiogenic factors (VEGF and FGF-2) and the length, volume and surface area of capillaries and reduced the expression of antiangiogenic factors (endostatin) in the cortex. In contrast, the L-NAME treatment attenuated the effects of running exercise.

CONCLUSIONS

Running exercise regulates proangiogenic factors, antiangiogenic factors and angiogenesis in the cerebral cortex via a partially NO-dependent mechanism, and influencing endogenous NO might potentially affect the exercise-related beneficial effects on cognitive ability and cortical capillaries.

Hyperbaric oxygenation applied before or after mild or hard stress: effects on the redox state in the muscle tissue

The mechanism is unclear for the reported protective effect of hyperbaric oxygen preconditioning against oxidative stress in tissues, and the distinct effects of hyperbaric oxygen applied after stress. The trained mice were divided into three groups: the control, hyperbaric oxygenation preconditioning, and hyperbaric oxygenation applied after mild (fasting) or hard (prolonged exercise) stress. After preconditioning, we observed a decrease in basal levels of nitric oxide, tetrahydrobiopterin, and catalase despite the drastic increase in inducible and endothelial nitric oxide synthases. Moreover, the basal levels of glutathione, related enzymes, and nitrosative stress only increased in the preconditioning group. The control and preconditioning groups showed a similar mild stress response of the endothelial and neuronal nitric oxide synthases. At the same time, the activity of all nitric oxide synthase, glutathione (GSH) in muscle, declined in the experimental groups but increased in control during hard stress. The results suggested that hyperbaric oxygen preconditioning provoked uncoupling of nitric oxide synthases and the elevated levels of GSH in muscle during this study, while hyperbaric oxygen applied after stress showed a lower level of GSH but higher recovery post-exercise levels in the majority of antioxidant enzymes. We discuss the possible mechanisms of the redox response and the role of the nitric oxide in this process.

Endothelial Dysfunction and Chronic Inflammation: The Cornerstones of Vascular Alterations in Age-Related Diseases

Vascular diseases of the elderly are a topic of enormous interest in clinical practice, as they have great epidemiological significance and lead to ever-increasing healthcare expenditures. The mechanisms underlying these pathologies have been increasingly characterized over the years. It has emerged that endothelial dysfunction and chronic inflammation play a diriment role among the most relevant pathophysiological mechanisms. As one can easily imagine, various processes occur during aging, and several pathways undergo irreversible alterations that can promote the decline and aberrations that trigger the diseases above. Endothelial dysfunction and aging of circulating and resident cells are the main characteristics of the aged organism; they represent the framework within which an enormous array of molecular abnormalities occur and contribute to accelerating and perpetuating the decline of organs and tissues. Recognizing and detailing each of these dysfunctional pathways is helpful for therapeutic purposes, as it allows one to hypothesize the possibility of tailoring interventions to the damaged mechanism and hypothetically limiting the cascade of events that drive the onset of these diseases. With this paper, we have reviewed the scientific literature, analysing the pathophysiological basis of the vascular diseases of the elderly and pausing to reflect on attempts to interrupt the vicious cycle that connotes the diseases of aging, laying the groundwork for therapeutic reasoning and expanding the field of scientific research by moving from a solid foundation.

Hyperbaric Oxygen Therapy and Tissue Regeneration: A Literature Survey

By addressing the mechanisms involved in transcription, signaling, stress reaction, apoptosis and cell-death, cellular structure and cell-to-cell contacts, adhesion, migration as well as inflammation; HBO upregulates processes involved in repair while mechanisms perpetuating tissue damage are downregulated. Many experimental and clinical studies, respectively, cover wound healing, regeneration of neural tissue, of bone and cartilage, muscle, and cardiac tissue as well as intestinal barrier function. Following acute injury or in chronic healing problems HBO modulates proteins or molecules involved in inflammation, apoptosis, cell growth, neuro- and angiogenesis, scaffolding, perfusion, vascularization, and stem-cell mobilization, initiating repair by a variety of mechanisms, some of them based on the modulation of micro-RNAs. HBO affects the oxidative stress response via nuclear factor erythroid 2-related factor 2 (Nrf2) or c-Jun N-terminal peptide and downregulates inflammation by the modulation of high-mobility group protein B1 (HMGB-1), toll-like receptor 4 and 2 (TLR-4, TLR-2), nuclear factor kappa-B (NFκB), hypoxia-inducible factor (HIF-1α) and nitric oxide (NO•). HBO enhances stem-cell homeostasis via Wnt glycoproteins and mammalian target of rapamycin (mTOR) and improves cell repair, growth, and differentiation via the two latter but also by modulation of extracellular-signal regulated kinases (ERK) and the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathway. The HBO-induced downregulation of matrix metalloproteinases-2 and 9 (MMP-2/-9), rho-associated protein kinase (ROCK) and integrins improve healing by tissue remodeling. Interestingly, the action of HBO on single effector proteins or molecules may involve both up- or downregulation, respectively, depending on their initial level. This probably mirrors a generally stabilizing potential of HBO that tends to restore the physiological balance rather than enhancing or counteracting single mechanisms.

The impact of aging and physical training on angiogenesis in the musculoskeletal system

Angiogenesis is the physiological process of capillary growth. It is strictly regulated by the balanced activity of agents that promote the formation of capillaries (pro-angiogenic factors) on the one hand and inhibit their growth on the other hand (anti-angiogenic factors). Capillary rarefaction and insufficient angiogenesis are some of the main causes that limit blood flow during aging, whereas physical training is a potent non-pharmacological method to intensify capillary growth in the musculoskeletal system. The main purpose of this study is to present the current state of knowledge concerning the key signalling molecules implicated in the regulation of skeletal muscle and bone angiogenesis during aging and physical training.

Influence of nitric oxide signaling mechanisms in cancer

Nitric oxide (NO) is a molecule with multiple biological functions that is involved in various pathophysiological processes such as neurotransmission and blood vessel relaxation as well as the endocrine system, immune system, growth factors, and cancer. However, in the carcinogenesis process, it has a dual behavior; at low doses, NO regulates homeostatic functions, while at high concentrations, it promotes tissue damage or acts as an agent for immune defense against microorganisms. Thus, its participation in the carcinogenic process is controversial. Cancer is a multifactorial disease that presents complex behavior. A better understanding of the molecular mechanisms associated with the initiation, promotion, and progression of neoplastic processes is required. Some hypotheses have been proposed regarding the influence of NO in activating oncogenic pathways that trigger carcinogenic processes, because NO might regulate some signaling pathways thought to promote cancer development and more aggressive tumor growth. Additionally, NO inhibits apoptosis of tumor cells, together with the deregulation of proteins that are involved in tissue homeostasis, promoting spreading to other organs and initiating metastatic processes. This paper describes the signaling pathways that are associated with cancer, and how the concentration of NO can serve a beneficial or pathological function in the initiation and promotion of neoplastic events.

ZNF667 facilitates angiogenesis after myocardial ischemia through transcriptional regulation of VASH1 and Wnt signaling pathway

Zinc finger protein 667 (ZNF667, also referred as Mipu1), a widely expressed KRAB/C₂H₂-type zinc finger transcription factor, can protect against hypoxic-ischemic myocardial injury. Pro-angiogenesis is regarded as a promising strategy for the treatment of acute myocardial infarction (AMI). However, whether ZNF667 is involved in the angiogenesis following AMI remains to be elucidated. The present study reported that the expression of ZNF667 in CD31-positive endothelial cells (ECs) was upregulated in the heart of AMI mice. Hypoxic challenge (1% oxygen) promoted the mRNA and protein expression of ZNF667 in the human umbilical vein endothelial cells (HUVECs) in a time-dependent manner. Moreover, ZNF667 promoted hypoxia-induced invasion and tube formation of HUVECs. Mechanically, ZNF667 could directly bind to the promoter of anti-angiogenic gene VASH1 and inhibit its expression. Consequently, VASH1 overexpression abolished hypoxic challenge or ZNF667 overexpression-induced invasion and tube formation of HUVECs. Further bioinformatic analyses suggested that overexpression of ZNF667 or knockdown of VASH1-induced differentially expressed genes in HUVECs were greatly enriched in the Wnt signaling pathway (DAAM1, LEF1, RAC2, FRAT1, NFATc2 and WNT5A). Together, these data suggested that ZNF667 facilitates myocardial ischemia-driven angiogenesis through transcriptional repression of VASH1 and regulation of Wnt signaling pathway.

Combination of polyglycerol sebacate coated with collagen for vascular engineering

Introduction: Here, we monitored the cytocompatibility of scaffolds consisting of poly (glycerol sebacate) (PGS) coated with collagen (Col) for endothelial cell activity after 72 hours. Methods: Human endothelial cells were allocated into Control, PGS, and PGS+Col groups. Scaffolds were characterized using FTIR and HNMR spectroscopy. Contact angel analysis and SEM were used to study wettability, surface morphology, and cell attachment. Cell survival was assessed using LDH leakage assay. Levels of Tie-1, Tie-2, VE-Cadherin, and VEGFR-2 were measured using western blotting and real-time PCR. Results: FTIR and HNMR analyses revealed the proper blending in PGS+Col group. SEM imaging exhibited a flat surface in the PGS group while thin Col fibers were detected in PGS+Col surface. The addition of Col to the PGS reduced the contract angle values from 97.3˚ to 81.1˚. Compared to PGS substrate alone, in PGS+Col group, cells appropriately attached to the surface. PGS and PGS+Col did not alter the leakage of LDH to the supernatant compared to control cells, showing the cytocopatiblity of PGS-based scaffolds. SOD and NO levels were increased significantly in PGS (p<0.05) and PGS+Col groups (p<0.001), respectively. We found that PGS+Col decreased Tie-1 content in endothelial cells whereas protein levels of Tie-2 and VE-Cadherin and expression of VEGFR-2 remained unchanged compared to PGS and control groups. Conclusion: Simultaneous application of Col and PGS can stimulate normal endothleial cell morphology without the alteration of tyrosine kinases receptors and cadherin.

The Alteration of HDL in Patients with AMI Inhibited Angiogenesis by Blocking ERK1/2 Activation

Objective. High-density lipoprotein (HDL) was found vasoprotective, but numbers of patients with acute myocardial infarction (AMI) have normal or even high levels of pathological HDL (pHDL). So, we investigate the mechanism of pHDL in AMI patients on angiogenesis. Methods. HDL with normal levels from healthy subjects (nHDL, control group, $n=20$ ) and patients with AMI (pHDL, experimental groups, $n=30$ ) were obtained by super high speed centrifugation. Then, effects of HDL on proliferation, migration, angiogenesis, and expression of ERK1/2 and its phosphorylation in human umbilical vein endothelial cells (HUVEC) with or without PD98059 (inhibitor of ERK1/2) preincubation were detected. Results. Compared with the control group (nHDL), HDL from the experimental group (pHDL) significantly inhibited the phosphorylation of ERK1/2, proliferation, migration, and angiogenesis of HUVEC ( $P<0.05$ ), while these effects of HDL could substantially be blocked by preincubation of PD98059 ( $P<0.05$ ). Conclusion. HDL in AMI patients affects angiogenesis by inhibiting ERK1/2 activation free from HDL levels.

Biodegradable Hollow-Structured Nanozymes Modulate Phenotypic Polarization of Macrophages and Relieve Hypoxia for Treatment of Osteoarthritis

Nanozymes are widely applied for treating various major diseases, including neurological diseases and tumors. However, the biodegradability of nanozymes remains a great challenge, which hinders their further clinical translation. Based on the microenvironment of osteoarthritis (OA), a representative pH-responsive biodegradable hollow-structured manganese Prussian blue nanozyme (HMPBzyme) is designed and applied for treatment of OA. HMPBzyme with good pH-responsive biodegradability, biocompatibility, and multi-enzyme activities is constructed by bovine serum albumin bubbles as a template-mediated biomineralization strategy. HMPBzyme suppresses hypoxia-inducible factor-1α (HIF-1α) expression and decreases reactive oxygen species (ROS) level in the in vitro experiment. Furthermore, HMPBzyme markedly suppresses the expression of ROS and alleviates the degeneration of cartilage in OA rat models. The results indicate that the biodegradable HMPBzyme inhibits oxidative damage and relieves hypoxia synergistically to suppress inflammation and promote the anabolism of cartilage extracellular matrix by protecting mitochondrial function and down-regulating the expression of HIF-1α, which modulates the phenotypic conversion of macrophages from pro-inflammatory M1 subtype to anti-inflammatory M2 subtype for OA treatment. This research lays a solid foundation for the design, construction, and biomedical application of biodegradable nanozymes and promotes the application of nanozymes in biomedicine.

SEC is an antiangiogenic virulence factor that promotes Staphylococcus aureus endocarditis independent of superantigen activity

The superantigen staphylococcal enterotoxin C (SEC) is critical for Staphylococcus aureus infective endocarditis (SAIE) in rabbits. Superantigenicity, its hallmark function, was proposed to be a major underlying mechanism driving SAIE but was not directly tested. With the use of S. aureus MW2 expressing SEC toxoids, we show that superantigenicity does not sufficiently account for vegetation growth, myocardial inflammation, and acute kidney injury in the rabbit model of native valve SAIE. These results highlight the critical contribution of an alternative function of superantigens to SAIE. In support of this, we provide evidence that SEC exerts antiangiogenic effects by inhibiting branching microvessel formation in an ex vivo rabbit aortic ring model and by inhibiting endothelial cell expression of one of the most potent mediators of angiogenesis, VEGF-A. SEC's ability to interfere with tissue revascularization and remodeling after injury serves as a mechanism to promote SAIE and its life-threatening systemic pathologies.

SDF-1α loaded bioengineered human amniotic membrane-derived scaffold transplantation in combination with hyperbaric oxygen improved diabetic wound healing

Based on its multifactorial nature, successful treatment of diabetic wounds requires combinatorial approach. In this regard, we hypothesized that engraftment of a bioengineered micro-porous three-dimensional human amniotic membrane-scaffold (HAMS) loaded by SDF-1α (SHAMS) in combination with hyperbaric oxygen (HBO), throughout mobilization and recruitment of endothelial progenitor cells (EPCs), could accelerate wound healing in rats with type 1 diabetes mellitus. To test this hypothesis, 30 days after inducting diabetes, an ischemic wound was created in rat skin and treatments were performed for 21 days. In addition to wounded non-diabetic (ND) group, diabetic animals were randomly divided into non-treated (NT-D), HBO-treated (HBO-D), HBO-treated plus HAMS transplantation (HBO+HAMS-D) or HBO-treated in combination with SHAMS transplantation (HBO+SHAMS-D) groups. Our results on post-wounding days 7, 14 and 21 showed that the wound closure, volume of new dermis and epidermis, numerical density of basal cells of epidermis, fibroblasts and blood vessels, number of proliferating cells, deposition of collagen and biomechanical properties of healed wound were considerably higher in both HBO+HAMS-D and HBO+SHAMS-D groups in comparison to those of the NT-D and HBO-D groups, and were the highest in HBO+SHAMS-D ones. The transcripts for Vegf, bFgf, and Tgf-β genes were significantly upregulated in all treatment regimens compared to NT-D group and were the highest for HBO+SHAMS-D group. This is while expression of Tnf-α and Il-1β as well as cell density of neutrophil and macrophage decreased more significantly in HBO+SHAMS-D group as compared with NT-D or HBO-D groups. Overall, it was found that using both HAMS transplantation and HBO treatment has more impact on diabetic wound healing. Moreover, SDF-1α loading on HAMS could transiently improve the wound healing process, as compared with the HBO+HAMS-D group on day 7 only.

Dracorhodin Perchlorate Regulates the Expression of Inflammatory Cytokines through the TLR4 Pathway and Improves Skin Wound Healing in Diabetic Rats

Background

Dragon's blood is a natural medicine with hemostatic and blood-activating effects and is used to promote wound healing. Dracorhodin perchlorate (DP) is a stable form of dracarhod and is used as a substitute for cochinchinenin. DP promotes the proliferation of rat fibroblasts and promotes wound healing in rats.

Methods

DP ointment (0.2 mg/mL) was applied to the skin wounds of nondiabetic and diabetic rats, and the skin of the wound was collected. Wound healing rate, H&E staining, Masson staining, TLR4 pathway, related inflammatory factors, nitric oxide synthase, and so forth were detected.

Results

DP treatment alleviated the prolonged inflammatory cell infiltration time and the increase in the TLR4 pathway and inflammatory factors caused by diabetes. DP also promoted wound healing by increasing eNOS protein expression and NO content in the later stage of wound healing.

Conclusion

DP promotes wound healing in diabetic rats by regulating the TLR4 pathway and related inflammatory factors. Therefore, adjuvant treatment of DP can be developed for diabetic wound healing.

Gene Therapy of Chronic Limb-Threatening Ischemia: Vascular Medical Perspectives

A decade ago, gene therapy seemed to be a promising approach for the treatment of chronic limb-threatening ischemia, providing new perspectives for patients without conventional, open or endovascular therapeutic options by potentially enabling neo-angiogenesis. Yet, until now, the results have been far from a safe and routine clinical application. In general, there are two approaches for inserting exogenous genes in a host genome: transduction and transfection. In case of transduction, viral vectors are used to introduce genes into cells, and depending on the selected strain of the virus, a transient or stable duration of protein production can be achieved. In contrast, the transfection of DNA is transmitted by chemical or physical processes such as lipofection, electro- or sonoporation. Relevant risks of gene therapy may be an increasing neo-vascularization in undesired tissue. The risks of malignant transformation and inflammation are the potential drawbacks. Additionally, atherosclerotic plaques can be destabilized by the increased angiogenesis, leading to arterial thrombosis. Clinical trials from pilot studies to Phase II and III studies on angiogenic gene therapy show mainly a mixed picture of positive and negative final results; thus, the role of gene therapy in vascular occlusive disease remains unclear.

Hyperbaric oxygen therapy mitigates left ventricular remodeling, upregulates MMP-2 and VEGF, and inhibits the induction of MMP-9, TGF-β1, and TNF-α in streptozotocin-induced diabetic rat heart

AIMS

Hyperbaric oxygen (HBO) therapy has been widely used for the adjunctive treatment of diabetic wounds, and is currently known to influence left ventricular (LV) function. However, morphological and molecular repercussions of the HBO in the diabetic myocardium remain to be described. We aimed to investigate whether HBO therapy would mitigate adverse LV remodeling caused by streptozotocin (STZ)-induced diabetes.

MAIN METHODS

Sixty-day-old Male Wistar rats were divided into four groups: Control (n = 8), HBO (n = 7), STZ (n = 10), and STZ + HBO (n = 8). Diabetes was induced by a single STZ injection (60 mg/kg, i.p.). HBO treatment (100% oxygen at 2.5 atmospheres absolute, 60 min/day, 5 days/week) lasted for 5 weeks. LV morphology was evaluated using histomorphometry. Gene expression analyzes were performed for LV collagens I (Col1a1) and III (Col3a1), matrix metalloproteinases 2 (Mmp2) and 9 (Mmp9), and transforming growth factor-β1 (Tgfb1). The Immunoexpression of cardiac tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) were also quantified.

KEY FINDINGS

HBO therapy prevented LV concentric remodeling, heterogeneous myocyte hypertrophy, and fibrosis in diabetic rats associated with attenuation of leukocyte infiltration. HBO therapy also increased Mmp2 gene expression, and inhibited the induction of Tgfb1 and Mmp9 mRNAs caused by diabetes, and normalized TNF-α and VEGF protein expression.

SIGNIFICANCE

HBO therapy had protective effects for the LV structure in STZ-diabetic rats and ameliorated expression levels of genes involved in cardiac collagen turnover, as well as pro-inflammatory and pro-angiogenic signaling.

Understanding Reactive Oxygen Species in Bone Regeneration: A Glance at Potential Therapeutics and Bioengineering Applications

Although the complex mechanism by which skeletal tissue heals has been well described, the role of reactive oxygen species (ROS) in skeletal tissue regeneration is less understood. It has been widely recognized that a high level of ROS is cytotoxic and inhibits normal cellular processes. However, with more recent discoveries, it is evident that ROS also play an important, positive role in skeletal tissue repair, specifically fracture healing. Thus, dampening ROS levels can potentially inhibit normal healing. On the same note, pathologically high levels of ROS cause a sharp decline in osteogenesis and promote nonunion in fracture repair. This delicate balance complicates the efforts of therapeutic and engineering approaches that aim to modulate ROS for improved tissue healing. The physiologic role of ROS is dependent on a multitude of factors, and it is important for future efforts to consider these complexities. This review first discusses how ROS influences vital signaling pathways involved in the fracture healing response, including how they affect angiogenesis and osteogenic differentiation. The latter half glances at the current approaches to control ROS for improved skeletal tissue healing, including medicinal approaches, cellular engineering, and enhanced tissue scaffolds. This review aims to provide a nuanced view of the effects of ROS on bone fracture healing which will inspire novel techniques to optimize the redox environment for skeletal tissue regeneration.

Aerobic-interval exercise with blood flow restriction potentiates early markers of metabolic health in man

AIM

This study examined whether aerobic-interval exercise with blood flow restriction (BFR) potentiates early markers of metabolic health compared to exercise with systemic hypoxia or normoxia in man.

METHODS

In a randomized-crossover fashion, eight healthy men completed nine 2-minute running bouts at 105% of their lactate threshold on three occasions separated by one week, either with BFR (BFR-trial), systemic hypoxia (HYP-trial) or normoxia (control; CON-trial). Near-infrared spectroscopy was used to assess the muscle level of hypoxia. A muscle biopsy was collected at rest and 3 hours after exercise to quantify genes involved in cholesterol synthesis (PGC-1α2), glucose disposal (GLUT4) and capillary growth (HIF-1α; VEGFA), as well as mitochondrial respiration (PGC-1α2/3), uncoupling (UCP3) and expansion (p53; COXIV-1/2; CS; AMPKα1/2).

RESULTS

The muscle level of hypoxia was matched between the BFR-trial and HYP-trial (~90%; P > .05), which was greater than the CON-trial (~70%; P < .05). PGC-1α2 increased most in the BFR-trial (16-fold vs CON-trial; 11-fold vs HYP-trial; P < .05). GLUT4 and VEGFA selectively increased by 2.0 and 3.4-fold, respectively in BFR-trial (P < .05), which was greater than CON-trial (1.2 and 1.3 fold) and HYP-trial (1.2 and 1.8 fold; P < .05). UCP3 increased more in BFR-trial than the HYP-trial (4.3 vs 1.6 fold), but was not different between BFR-trial and CON-trial (2.1 fold) or between CON-trial and HYP-trial (P > .05). No trial differences were evident for other genes (P > .05).

CONCLUSION

Independent of the muscle level of hypoxia, BFR-exercise potentiates early markers of metabolic health associated with the regulation of cholesterol production and glucose homeostasis in man.

Red and near infrared light-stimulated angiogenesis mediated via Ca2+ influx, VEGF production and NO synthesis in endothelial cells in macrophage or malignant environments

Irradiation with red or near-infrared (NIR) light in low level light therapy (LLLT) is found to stimulate cellular processes and bioenergetics, resulting in enhanced wound healing, pain control, neurodegenerative diseases treatment, etc. During light irradiation of tissues and organs, different cells are affected, though the connection between photostimulation of cells and their environmental conditions remains poorly understood. In this report, red/NIR light-stimulated angiogenesis is investigated using endothelial cells in vitro, with a focus on the capillary-like structure (CLS) formation and the respective biochemical processes in cells under conditions proximate to a healthy or malignant environment, which strongly defines angiogenesis. To model environmental conditions for endotheliocytes in vitro, the cell culture environment was supplemented by an augmented conditioned medium from macrophages or cancer cells. The biochemical processes in endothelial cell cultures were investigated with and without irradiation by red (650 nm) and near-infrared (808 nm) laser diodes and under normoxia or hypoxia conditions. A light-stimulated angiogenesis has been found, with a more efficient stimulation by 650 nm light compared to 808 nm light. It was shown that the irradiation with light promoted extracellular Ca²⁺ influx, fostered cell cycle progression, proliferation and NO generation in endothelial cells, and caused an increase in vascular endothelial growth factor (VEGF) production by endothelial cells and M2 macrophages under hypoxia conditions. The activation of VEGF production by macrophages was found to be associated with an increase in the number of M2 macrophages after light irradiation under hypoxia conditions. Thus, a new pathway of an activation of the endothelial cell metabolism, which is related with the extracellular Ca²⁺ influx after light irradiation, has been revealed. STATEMENT OF SIGNIFICANCE: Red/NIR light-stimulated angiogenesis has been studied using endothelial cells in vitro, with focus on CLS formation and the respective biochemical processes in cell models proximate to a healthy or malignant environment. A light-stimulated angiogenesis has been found, stimulated via extracellular Ca²⁺ influx, cell cycle progression, proliferation and NO generation, VEGF production increase by endothelial cells under hypoxia conditions.

Can static electric fields increase the activity of nitric oxide synthase and induce oxidative stress and damage of spleen?

With the rapid development of ultra-high-voltage (UHV) direct-current (DC) transmissions, the impact of static electric fields (SEF) in the vicinity of overhead UHV DC transmission lines on health has aroused much public concern. This study explored the effects of 56.3kV/m SEF on the spleen of mice. Results showed that SEF exposure of 21days significantly increased malonic dialdehyde content, superoxide dismutase activity, calcineurin activity, nitric oxide synthase (NOS) activity, and the mRNA expression levels of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the spleen and caused the separation of nucleus and nuclear membrane, the disappearance of mitochondrial membrane, and the deficiency of mitochondrial cristae in splenic lymphocytes. By analysis and discussion, it was deduced that SEF could induce oxidative stress of the spleen by increasing the activity of NOS. Oxidative stress could further cause ultrastructural changes of splenic lymphocytes. Moreover, oxidative stress could cause the increase of the mRNA expression levels of TNF-α and NF-κB, which contributed to the occurrence of spleen inflammation.

Promotion of angiogenesis toward transplanted ovaries using nitric oxide releasing nanoparticles in fibrin hydrogel

Transplantation of ovary is one method of facilitating fertility preservation to increase the quality of life of cancer survivors. Immediately after transplantation, ovaries are under ischemic conditions owing to a lack of vascular anastomosis between the graft and host tissues. The transplanted ovaries can suffer damage because of lack of oxygen and nutrients, resulting in necrosis and dysfunction. In the technique proposed in this paper, the ovary is encapsulated with nitric oxide-releasing nanoparticles (NO-NPs) in fibrin hydrogels, which form a carrying matrix to prevent ischemic damage and accelerate angiogenesis. The low concentration of NO released from mPEG-PLGA nanoparticles elicits blood vessel formation, which allows transplanted ovaries in the subcutis to recover from the ischemic period. In experiments with mice, the NO-NPs/fibrin hydrogel improved the total number and quality of ovarian follicles after transplantation. The intra-ovarian vascular density was 4.78 folds higher for the NO-NPs/fibrin hydrogel groups compared to that for the nontreated groups. Finally,in vitrofertilization revealed a successful blastocyst formation rate for NO-NPs/fibrin hydrogel coated ovaries. Thus, NO-NPs/fibrin hydrogels can provide an appropriate milieu to promote angiogenesis and be considered as adjuvant surgery materials for fertility preservation.

Hyperbaric oxygen enhances collagen III formation in wound of ZDF rat

Diabetic foot ulcer (DFU) is a serious complication of diabetes and hyperbaric oxygen therapy (HBOT) is also considered in comprehensive treatment. The evidence supporting the use of HBOT in DFU treatment is controversial. The aim of this work was to introduce a DFU model in ZDF rat by creating a wound on the back of an animal and to investigate the effect of HBOT on the defect by macroscopic evaluation, quantitative histological evaluation of collagen (types I and III), evaluation of angiogenesis and determination of interleukin 6 (IL6) levels in the plasma. The study included 10 rats in the control group (CONT) and 10 in the HBOT group, who underwent HBOT in standard clinical regimen. Histological evaluation was performed on the 18th day after induction of defect. The results show that HBOT did not affect the macroscopic size of the defect nor IL6 plasma levels. A volume fraction of type I collagen was slightly increased by HBOT without reaching statistical significance (1.35+/-0.49 and 1.94+/-0.67 %, CONT and HBOT, respectively). In contrast, the collagen type III volume fraction was ~120 % higher in HBOT wounds (1.41+/-0.81 %) than in CONT ones (0.63+/-0.37 %; p=0.046). In addition, the ratio of the volume fraction of both collagens in the wound ((I+III)w) to the volume fraction of both collagens in the adjacent healthy skin ((I+III)h) was ~65 % higher in rats subjected to HBOT (8.9+/-3.07 vs. 5.38+/-1.86 %, HBOT and CONT, respectively; p=0.028). Vessels density (number per 1 mm2) was found to be higher in CONT vs. HBOT (206.5+/-41.8 and 124+/-28.2, respectively, p<0.001). Our study suggests that HBOT promotes collagen III formation and decreases the number of newly formed vessels at the early phases of healing.

Effect of Hyperbaric Oxygenation on Blood Cytokines and Arginine Derivatives; No Evidence for Induction of Inflammation or Endothelial Injury

(1) Background: Hyperbaric oxygen therapy (HBOT) uses 100% oxygen delivered at 1.5-3 times the atmospheric pressure in a specialised chamber to achieve supraphysiological oxygen tension in blood and tissues. Besides its target, HBOT may affect inflammation, endothelial function or angiogenesis. This study analysed the effect of HBOT on blood concentrations of factors that may affect these processes in patients with necrotizing soft-tissue infections (NSTI), aseptic bone necrosis (ABN) and idiopathic sudden sensory neural hearing loss (ISSNHL). (2) Methods: Concentrations asymmetric dimethylarginine (ADMA) and other arginine derivatives were measured with liquid chromatography/mass spectrometry, whereas ELISA was used to quantitate vascular endothelial growth factor (VEGF) and cytokines (IL-1, IL-4, IL-6, IL-10, TGF-β) before and after HBOT in 80 patients (NSTI n = 21, ISSNHL n = 53, ABN n = 6). (3) Results: While some differences were noted between patient groups in ADMA and other arginine derivatives as well as in cytokine concentrations, HBOT did not affect any of these parameters. (4) Conclusions: While cytokines and arginine derivatives concentrations were modified by underlying pathology, hyperbaric oxygenation did not immediately modify it suggesting that it is neutral for inflammation and is not inducing endothelial injury.