Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Factors affecting suboptimal maturation of autogenous arteriovenous fistula in elderly patients with diabetes:A narrative review

Autogenous arteriovenous fistula (AVF) is considered the preferred vascular access choice for individuals undergoing maintenance hemodialysis (MHD) and is widely utilized in China, as reported by the Dialysis Outcomes and Practice Patterns Study. Despite its popularity, the significant incidence of poor AVF maturation often leads to the need for central venous catheter insertion, increasing the risk of complications like superior vena cava stenosis and catheter-related infections, which in turn raises the overall mortality risk. With the prevalence of diabetes rising globally among the elderly and diabetic kidney disease being a leading cause of end-stage renal disease necessitating renal replacement therapy, our retrospective review aims to explore the various factors affecting AVF maturation in this specific patient population. While there have been numerous studies examining AVF complications in MHD patients, including issues like failure, patency loss, stenosis, thrombosis, poor maturation, and other influencing factors, there remains a gap in large-scale clinical studies focusing on the incidence and risk factors for immature AVF specifically in elderly diabetic patients. This paper delves into the pathophysiological mechanisms, diagnostic criteria, and unique considerations surrounding AVF maturation in elderly diabetic patients, distinguishing them from the general population. Our literature review reveals that elderly diabetic patients exhibit a higher risk of AVF immaturity compared to the general population. Additionally, there exists a continuing discourse regarding several aspects related to this group, including the choice of dialysis access, timing of AVF surgery, and surgical site selection. Furthermore, we delve into the management strategies for vascular access within this specific group with the goal of providing evidence-based guidance for the establishment and maintenance of functional vascular access in elderly diabetic patients.

The Intriguing World of Vascular Remodeling, Angiogenesis, and Arteriogenesis

Vascular remodeling is a very general feature related to angiogenesis and arteriogenesis, which are involved in neovascularization processes [...].

Photochemical Modification of the Extracellular Matrix to Alter the Vascular Remodeling Process

Therapeutic interventions for vascular diseases aim at achieving long-term patency by controlling vascular remodeling. The extracellular matrix (ECM) of the vessel wall plays a crucial role in regulating this process. This study introduces a novel photochemical treatment known as Natural Vascular Scaffolding, utilizing a 4-amino substituted 1,8-naphthimide (10-8-10 Dimer) and 450 nm light. This treatment induces structural changes in the ECM by forming covalent bonds between amino acids in ECM fibers without harming vascular cell survival, as evidenced by our results. To further investigate the mechanism of this treatment, porcine carotid artery segments were exposed to 10-8-10 Dimer and light activation. Subsequent experiments subjected these segments to enzymatic degradation through elastase or collagenase treatment and were analyzed using digital image analysis software (MIPAR) after histological processing. The results demonstrated significant preservation of collagen and elastin structures in the photochemically treated vascular wall, compared to controls. This suggests that photochemical treatment can effectively modulate vascular remodeling by enhancing the resistance of the ECM scaffold to degradation. This approach shows promise in scenarios where vascular segments experience significant hemodynamic fluctuations as it reinforces vascular wall integrity and preserves lumen patency. This can be valuable in treating veins prior to fistula creation and grafting or managing arterial aneurysm expansion.

Increased expression of the P2Y12 receptor is involved in the failure of autogenous arteriovenous fistula caused by stenosis

OBJECTIVE

This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis.

METHODS

Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription-polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression.

RESULTS

Expression levels of P2Y12, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12+/TGF-β1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues.

CONCLUSION

Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs.