Availability of adipose-derived stem cells in patients undergoing vascular surgical procedures.

BACKGROUND: Most research evaluating adipose-derived stem cells (ASC) uses tissue obtained from young, healthy patients undergoing plastic surgical procedures. Given the propensity of other adult stem cell lines to diminish with increasing patient age and co-morbidities, we assess the availability of ASC in elderly patients undergoing vascular surgical procedures, and evaluate their acquisition of endothelial cell (EC) traits to define their potential use in vascular tissue engineering. METHODS AND METHODS: Adipose tissue obtained by liposuction from patients undergoing vascular procedures (n = 50) was digested with collagenase and centrifuged to remove mature adipocytes. The resultant number of cells, defined as the stromal-vascular (SV) pellet, was quantified. Following a 7-d culture period and negative selection for CD31 and CD45, the resultant number of ASC was quantified. After culture in differentiating media (EMG-2), ASCs were tested for the acquisition of endothelial-specific traits (expression of CD31, realignment in shear, cord formation on Matrigel). RESULTS: The SV pellet contained 2.87 ± 0.34 × 10(5) cells/g fat, and the resultant number of ASCs obtained was 1.41 ± 0.18 × 10(5) cells/g fat. Flow cytometry revealed a homogeneous ASC population (>98% positive for CD13, 29, 90). Advanced age or co-morbidity (obesity, diabetes, renal or peripheral vascular disease) did not significantly alter yield of ASC. After culture in differentiating media (EMG-2), ASCs acquired each of the endothelial-specific traits. CONCLUSION: ASC isolation appears independent of age and co-morbidities, and ASCs harvested from patients with vascular disease retain their ability to differentiate into endothelial-like cells. Adipose tissue, therefore, is a practical source of autologous, adult stem cells for vascular tissue engineering.

Paraspinous muscle flap reconstruction of complex midline back wounds: Risk factors and postreconstruction complications.

With increasingly complex spine surgeries now being performed on a more comorbid patient population, the reconstruction of midline back wounds from these procedures is becoming a frequent dilemma encountered by plastic surgery. The purpose of this study is to examine the effect of various preoperative risk factors on postoperative wound healing complications after paraspinous muscle flap reconstruction of midline back defects. An Institutional Review Board-approved, 11-year, retrospective, office and hospital chart review was conducted. All adult patients who underwent paraspinous muscle flap reconstruction during the study period were included. There were 92 patients in the study, representing the largest reported series to-date for the paraspinous muscle flap procedure. Mean follow-up was 120 days. Several wound-healing risk factors were present in this patient population: 72% were malnourished, 41% had hypertension, 37% were obese, 34% had a history of smoking, 32% had diabetes, 16% were on chronic steroids, 14% had a history of more than 2 previous spine surgeries, and 9% had a history of radiation to the wound area. Factors significantly (P < 0.05) associated with postreconstruction wound complications included history of traumatic spine injury, prereconstruction hardware removal, a history of more than 2 spine surgeries, hypertension, and lumbar wound location. This patient population possesses multiple comorbidities making complex wound healing difficult. Several specific risk factors are associated with an increased rate of postreconstruction wound complications after paraspinous muscle flaps. The paraspinous muscle flap remains an important tool for spinal wound reconstruction in the reconstructive surgeon's armamentarium.

Decellularized vein as a potential scaffold for vascular tissue engineering.

PURPOSE: Current strategies to create small-diameter vascular grafts involve seeding biocompatible, compliant scaffolds with autologous vascular cells. Our purpose was to study the composition and strength of decellularized vein to determine its potential as a vascular tissue-engineering scaffold. METHODS: Intact human greater saphenous vein specimens were decellularized by using sodium dodecyl sulfate (SDS). Residual cellular and extracellular matrix composition was studied with light and electron microscopy as well as immunohistochemistry. Burst and suture-holding strength was measured in vitro by insufflation and pull-through techniques. To assess initial handling and durability of decellularized vein in vivo, a canine model was developed wherein decellularized canine jugular veins were implanted as carotid interposition grafts in recipient animals. After two weeks of arterial perfusion, these grafts were studied with duplex imaging and histologic methods. RESULTS: Human saphenous vein decellularized by using SDS was devoid of endothelial cells and >94% of the cells resident within the vein wall. Collagen morphology appeared unchanged, and elastin staining decreased only slightly. Basement membrane collagen type IV remained intact. Compared with fresh vein, decellularized vein had similar in vitro burst (2480 +/- 460 mm Hg vs 2380 +/- 620 mm Hg; P >.05) and suture-holding (185 +/- 30 gm vs 178 +/- 66 gm; P >.05) strength. Decellularized canine vein functioned well in vivo without dilation, anastomotic complication, or rupture over 2 weeks of arterial perfusion. CONCLUSIONS: Vein rendered acellular with SDS has well-preserved extracellular matrix, basement membrane structure, and strength sufficient for vascular grafting. These properties suggest proof of concept for its use as a scaffold for further vascular tissue engineering. CLINICAL RELEVANCE: The following research examines the creation of a new small-diameter bypass graft. It is clinically relevant to patients who need distal arterial bypass, coronary artery bypass, or hemodialysis access, but who do not have adequate autologous vein for their surgeries. Future investigations will involve further tissue engineering of this vascular scaffold (eg, autologous endothelial seeding of its lumen) and testing the clinical usefulness of the completed graft.