Hypoxia-induced retinal pigment epithelium cell-derived bFGF promotes the migration and angiogenesis of HUVECs through regulating TGF-β1/smad2/3 pathway

Ranibizumab for the treatment of retinopathy of prematurity: systematic review and meta-analysis

Anti-VEGF drugs like ranibizumab can be used to treat retinopathy of prematurity (ROP) by halting the formation of abnormal blood vessels, or lasers can be used to burn the edges of the retina where these vessels are present. The objective is to compare the efficacy for ROP between ranibizumab and laser therapy.

Material and methods

Electronic searches will be carried out in medical databases with key words and controlled vocabulary terms. Randomized controlled trials (RCT) will be assessed. The primary outcome will be the full ROP regression. Two reviewers will extract the data using predefined forms and, to assess the quality of the study, we will use RoB 2.0, the tool for randomized controlled trials developed by the Cochrane Collaboration. We used a combination of the inverse-variance approach and random-effects models for the meta-analysis.

Results

The eyes of 182 preterm infants who had ranibizumab treatment were assessed in a total of 364 eyes, and 135 infants received laser therapy. The follow-up period was between 6 and 24 months. Ranibizumab was not associated with greater regression of ROP compared to laser therapy in preterm infants (RR: 1.09, CI 95%: 0.95-1.24; p: 0.22). Also, ranibizumab was not associated with recurrence of ROP compared to laser therapy in preterm infants (RR: 3.77, CI 95%: 0.55-25.81; p: 0.22).

Conclusions

The efficacy of ranibizumab compared to laser is very uncertain in terms of ROP regression and decreased ROP recurrence in preterm infants.

Systematic Review Registration

identifier PROSPERO (CRD42022324150).

Complement factor H inhibits endothelial cell migration through suppression of STAT3 signaling

Complement factor H (CFH), a major soluble inhibitor of complement, is a plasma protein that directly interacts with the endothelium of blood vessels. Mutations in the CFH gene lead to diseases associated with excessive angiogenesis; however, the underlying mechanisms are unknown. The present study aimed to determine the effects of CFH on endothelial cells and to explore the underlying mechanisms. The adenoviral plasmid expressing CFH was transduced into HepG2 cells, and the culture medium supernatant was collected and co-cultured with human umbilical vein endothelial cells (HUVECs). Cell proliferation was measured by CCK8 and MTT assays, and cell migration was measured by wound healing and Transwell assays. Reverse transcription-quantitative PCR was performed to detect gene transcription. Western blotting was used to determine protein levels. The results revealed that CFH can inhibit migration, but not viability, of HUVECs. In addition, CFH did not significantly alter MAPK or TGF-β signaling, whereas it decreased STAT3 phosphorylation in HUVECs. Furthermore, CFH failed to reduce migration of HUVECs, with inhibition of STAT3 signaling by STATTIC or activation of STAT3 signaling by overexpression of STAT3 (Y705D) compromising CFH-inhibited HUVEC migration. CFH also decreased the expression levels of vascular endothelial growth factor receptor 2, a downstream effector of STAT3 mediating endothelial cell migration. In conclusion, the present study suggested that CFH may be a potential therapeutic target for angiogenesis-related diseases.

PRDM16 regulates arterial development and vascular integrity

Proper vascular formation is regulated by multiple signaling pathways. The vascular endothelial growth factor (VEGF) signaling promotes endothelial proliferation. Notch and its downstream targets act to lead endothelial cells toward an arterial fate through regulation of arterial gene expression. However, the mechanisms of how endothelial cells (ECs) in the artery maintain their arterial characteristics remain unclear. Here, we show that PRDM16 (positive regulatory domain-containing protein 16), a zinc finger transcription factor, is expressed in arterial ECs, but not venous ECs in developing embryos and neonatal retinas. Endothelial-specific deletion of Prdm16 induced ectopic venous marker expression in the arterial ECs and reduced vascular smooth muscle cell (vSMC) recruitment around arteries. Whole-genome transcriptome analysis using isolated brain ECs show that the expression of Angpt2 (encoding ANGIOPOIETIN2, which inhibits vSMC recruitment) is upregulated in the Prdm16 knockout ECs. Conversely, forced expression of PRDM16 in venous ECs is sufficient to induce arterial gene expression and repress the ANGPT2 level. Together, these results reveal an arterial cell-autonomous function for PRDM16 in suppressing venous characteristics in arterial ECs.

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

Platelet Rich Plasma in the Repair of Articular Cartilage Injury: A Narrative Review

OBJECTIVE

This paper reviews the research of platelet-rich plasma (PRP) in articular cartilage injury repair, to assess the mechanism, utilization, and efficacy of PRP in the treatment of articular cartilage injury, hoping to provide a theoretical basis for the clinical application of PRP in the future.

MATERIALS AND METHODS

A comprehensive database search on PRP applications in cartilage repair was performed. Among them, the retrieval time range of PRP in clinical trials of repairing knee cartilage injury was from January 1, 2021 to January 1, 2022. Non-clinical trials and studies unrelated to cartilage injury were excluded.

RESULT

PRP can affect inflammation, angiogenesis, cartilage protection, and cellular proliferation and differentiation after articular cartilage injury through different pathways. In all, 13 clinical trials were included in the analysis.

CONCLUSION

PRP is an emergent therapeutic approach in tissue engineering. Most studies reported that PRP has a positive effect on cartilage injury, improving the joint function, meanwhile there is a lack of standardized standards. The technology of PRP in the repair and treatment of articular cartilage injury is worthy of further research.

Stimulation by Exosomes from Hypoxia Preconditioned Human Umbilical Vein Endothelial Cells Facilitates Mesenchymal Stem Cells Angiogenic Function for Spinal Cord Repair

Revascularization treatment is a critical measure for tissue engineering therapies like spinal cord repair. As multipotent stem cells, mesenchymal stem cells (MSCs) have proven to regulate the lesion microenvironment through feedback to the microenvironment signals. The angiogenic capacities of MSCs have been reported to be facilitated by vein endothelial cells in the niche. As emerging evidence demonstrated the roles of exosomes in cell-cell and cell-microenvironment communications, to cope with the ischemia complication for treatment of traumatic spinal cord injury, the study extracts the microenvironment factors to stimulate angiogenic MSCs through using exosomes (EX) derived from hypoxic preconditioned (HPC) human umbilical vein endothelial cells (HUVEC). The HPC treatment with a hypoxia time segment of only 15 min efficiently enhanced the function of EX in facilitating MSCs angiogenesis activity. MSCs stimulated by HPC-EX showed significant tube formation within 2 h, and the in vivo transplantation of the stimulated MSCs elicited effective nerve tissue repair after rat spinal cord transection, which could be attributed to the pro-angiogenic and anti-inflammatory impacts of the MSCs. Through the simulation of MSCs using HPC-tailored HUVEC exosomes, the results proposed an efficient angiogenic nerve tissue repair strategy for spinal cord injury treatment and could provide inspiration for therapies based on stem cells and exosomes.

Coaxially Bioprinted Cell-Laden Tubular-Like Structure for Studying Glioma Angiogenesis

Glioblastomas are the most frequently diagnosed and one of the most lethal primary brain tumors, and one of their key features is a dysplastic vascular network. However, because the origin of the tumor blood vessels remains controversial, an optimal preclinical tumor model must be established to elucidate the tumor angiogenesis mechanism, especially the role of tumor cells themselves in angiogenesis. Therefore, shell-glioma cell (U118)-red fluorescent protein (RFP)/core-human umbilical vein endothelial cell (HUVEC)-green fluorescent protein (GFP) hydrogel microfibers were coaxially bioprinted. U118–RFP and HUVEC–GFP cells both exhibited good proliferation in a three-dimensional (3D) microenvironment. The secretability of both vascular endothelial growth factor A and basic fibroblast growth factor was remarkably enhanced when both types of cells were cocultured in 3D models. Moreover, U118 cells promoted the vascularization of the surrounding HUVECs by secreting vascular growth factors. More importantly, U118–HUVEC-fused cells were found in U118–RFP/HUVEC–GFP hydrogel microfibers. Most importantly, our results indicated that U118 cells can not only recruit the blood vessels of the surrounding host but also directly transdifferentiate into or fuse with endothelial cells to participate in tumor angiogenesis in vivo. The coaxially bioprinted U118–RFP/HUVEC–GFP hydrogel microfiber is a model suitable for mimicking the glioma microenvironment and for investigating tumor angiogenesis.

Minimally invasive co-injection of modular micro-muscular and micro-vascular tissues improves in situ skeletal muscle regeneration

Various conventional treatment strategies for volumetric muscle loss (VML) are often hampered by the extreme donor site morbidity, the limited availability of quality muscle flaps, and complicated, as well as invasive surgical procedures. The conventional biomaterial-based scaffolding systems carrying myoblasts have been extensively investigated towards improving the regeneration of the injured muscle tissues, as well as their injectable forms. However, the applicability of such designed systems has been restricted due to the lack of available vascular networks. Considering these facts, here we present the development of a unique set of two minimally invasively injectable modular microtissues, consisting of mouse myoblast (C2C12)-laden poly(lactic-co-glycolic acid) porous microspheres (PLGA PMs), or the micro-muscles, and human umbilical vein endothelial cell (HUVEC)-laden poly(ethylene glycol) hollow microrods (PEG HMs), or the microvessels. Besides systematic in vitro investigations, the myogenic performance of these modular composite microtissues, when co-injected, was explored in vivo using a mouse VML model, which confirmed improved in situ muscle regeneration and remolding. Together, we believe that the construction of these injectable modular microtissues and their combination for minimally invasive therapy provides a promising method for in situ tissue healing.