Dortch, John D.

Mesenchymal stem cells (MSCs) have been shown to improve regeneration of injured tissues in vivo. Several in vitro studies and animal models have demonstrated improvement in MSCs paracrine effects under hypoxic conditions. Moreover, several studies suggested that the pro B-type natriuretic peptide (pro-BNP) could be involved in the stimulation of postischemic vascular regeneration. The purpose of this study was to investigate the effect of critical limb ischemia, in a human model, on in-situ adipose derived mesenchymal stem cells (ADMSCs) and to determine whether serum levels of N-terminal pro-BNP correlate with ADMSCs counts and associated paracrine effects. Lipoaspirate samples of ≥ 10mL were collected from ischemic limbs (ischemic group) and compared to control (without ischemia). MSCs were characterized by frequency, viability, differentiation potential, cytokines expression, and cell surface markers. Serum NT pro-BNP was measured as well. MSCs counts were 9-to-10-fold higher in patients with ischemic limbs (mean 7952 MSC/mL ± 542) than controls (mean 790 MSC/mL ± 65). Pro-BNP levels (1878-4757 pg/mL) were approximately 8-to-26-fold higher than in age- and sex-matched controls. Furthermore, there were positive correlations between pro-BNP levels and MSCs counts in the ischemic group. In conclusion, patients with critical limb ischemia (CLI) have higher levels of pro-BNP and MSCs counts than controls. Increased levels of pro-BNP and MSCs counts can be considered humoral and cellular surrogates of ischemia and hypoxia in patients with CLI. This supports recent studies that suggest that the increase production of peripheral BNP may be a stem cells-mediated response to stimulate angiogenesis in the ischemic skeletal muscles.

Background Venous congestion after deep inferior epigastric artery perforator (DIEP) flap breast reconstruction is a complication that may be partially attributable to variations in venous abdominal wall anatomy. In previous work, we have shown that ferumoxytol may be used as a bloodpool contrast agent to perform high-resolution venous imaging. Our current aim was to use this technology to perform a detailed analysis of the venous anatomy among patients undergoing DIEP flap breast reconstruction. Methods All patients undergoing DIEP flap reconstruction with preoperative ferumoxytol-enhanced magnetic resonance angiography (FE-MRA) were retrospectively reviewed. A detailed anatomic analysis of each abdominal wall on FE-MRAwas performed before review of operative findings. Statistical analysis was used to determine venous characteristics associated with superficial inferior epigastric vein (SIEV) augmentation. Results From 2012 to 2016, 59 patients underwent preoperative FE-MRA. This resulted in imaging for 118 hemiabdomen and 99 flaps. Superficial-deep communication was identified in 117 of 118 hemiabdomen. Fifty (93%) of 59 patients had greater than 1-mm venous communication of the superficial system across midline. Reconstructed breasts were based on dominant medial row perforators in 82 (83%) of 99 flaps. The mean diameters of the SIEVand dominant venous perforator were 3.8 and 2.8mm, respectively. Anatomic characteristics associated with SIEVaugmentation included SIEVdiameter ( P = 0.01), dominant perforator diameter ( P = 0.04), and the ratio between these 2 variables ( P = 0.001). Conclusions Ferumoxytol-enhanced magnetic resonance angiography provides excellent imaging of the venous system. Anatomic characteristics such as the diameter of the SIEVand the diameter of the dominant perforator may be useful in determining which flaps require venous augmentation using the SIEV.