TY - JOUR

T1 - Micro-RNA-Regulated Proangiogenic Signaling in Arteriovenous Loops in Patients with Combined Vascular and Soft-Tissue Reconstructions

T2 - Revisiting the Nutrient Flap Concept

AU - Henn, Dominic

AU - Abu-Halima, Masood

AU - Falkner, Florian

AU - Wermke, Dominik

AU - Meme, Lilian G

AU - Kühner, Clemens

AU - Keller, Andreas

AU - Kneser, Ulrich

AU - Meese, Eckart

AU - Schmidt, Volker J

PY - 2018

Y1 - 2018

N2 - BACKGROUND: The placement of arteriovenous loops can enable microvascular anastomoses of free flaps when recipient vessels are scarce. In animal models, elevated fluid shear stress in arteriovenous loops promotes neoangiogenesis. Anecdotal reports in patients indicate that vein grafts used in free flap reconstructions of ischemic lower extremities are able to induce capillary formation. However, flow-stimulated angiogenesis has never been systematically investigated in humans, and it is unclear whether shear stress alters proangiogenic signaling pathways within the vascular wall of human arteriovenous loops.METHODS: Eight patients with lower extremity soft-tissue defects underwent two-stage reconstruction with arteriovenous loop placement, and free flap anastomoses to the loops 10 to 14 days later. Micro-RNA (miRNA) and gene expression profiles were determined in tissue samples harvested from vein grafts of arteriovenous loops by microarray analysis and quantitative real-time polymerase chain reaction. Samples from untreated veins served as controls.RESULTS: A strong deregulation of miRNA and gene expression was detected in arteriovenous loops, showing an overexpression of angiopoietic cytokines, oxygenation-associated genes, vascular growth factors, and connexin-43. The authors discovered inverse correlations along with validated and bioinformatically predicted interactions between angiogenesis-regulating genes and miRNAs in arteriovenous loops.CONCLUSIONS: The authors' findings demonstrate that elevated shear stress triggers proangiogenic signaling pathways in human venous tissue, indicating that arteriovenous loops may have the ability to induce neoangiogenesis in humans. The authors' data corroborate the nutrient flap hypothesis and provide a molecular background for arteriovenous loop-based tissue engineering with potential clinical applications for soft-tissue defect reconstruction.

AB - BACKGROUND: The placement of arteriovenous loops can enable microvascular anastomoses of free flaps when recipient vessels are scarce. In animal models, elevated fluid shear stress in arteriovenous loops promotes neoangiogenesis. Anecdotal reports in patients indicate that vein grafts used in free flap reconstructions of ischemic lower extremities are able to induce capillary formation. However, flow-stimulated angiogenesis has never been systematically investigated in humans, and it is unclear whether shear stress alters proangiogenic signaling pathways within the vascular wall of human arteriovenous loops.METHODS: Eight patients with lower extremity soft-tissue defects underwent two-stage reconstruction with arteriovenous loop placement, and free flap anastomoses to the loops 10 to 14 days later. Micro-RNA (miRNA) and gene expression profiles were determined in tissue samples harvested from vein grafts of arteriovenous loops by microarray analysis and quantitative real-time polymerase chain reaction. Samples from untreated veins served as controls.RESULTS: A strong deregulation of miRNA and gene expression was detected in arteriovenous loops, showing an overexpression of angiopoietic cytokines, oxygenation-associated genes, vascular growth factors, and connexin-43. The authors discovered inverse correlations along with validated and bioinformatically predicted interactions between angiogenesis-regulating genes and miRNAs in arteriovenous loops.CONCLUSIONS: The authors' findings demonstrate that elevated shear stress triggers proangiogenic signaling pathways in human venous tissue, indicating that arteriovenous loops may have the ability to induce neoangiogenesis in humans. The authors' data corroborate the nutrient flap hypothesis and provide a molecular background for arteriovenous loop-based tissue engineering with potential clinical applications for soft-tissue defect reconstruction.

KW - Arteriovenous Shunt, Surgical/methods

KW - Free Tissue Flaps/blood supply

KW - Gene Expression Profiling

KW - Humans

KW - Intercellular Signaling Peptides and Proteins/metabolism

KW - Lower Extremity/surgery

KW - MicroRNAs/metabolism

KW - Microarray Analysis

KW - Microsurgery

KW - Real-Time Polymerase Chain Reaction

KW - Plastic Surgery Procedures/methods

KW - Soft Tissue Injuries/metabolism

KW - Veins/metabolism

U2 - 10.1097/PRS.0000000000004750

DO - 10.1097/PRS.0000000000004750

M3 - Journal article

C2 - 29979372

VL - 142

SP - 489e-502e

JO - Plastic and Reconstructive Surgery

JF - Plastic and Reconstructive Surgery

SN - 0032-1052

IS - 4

ER -