Vu T Nguyen

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (6)13.64 Total impact

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    ABSTRACT: Composite tissue allograft transplantation is limited by risks of long-term immunosuppression. The authors investigated whether short-term immunosuppression combined with recipient immature dendritic cells pulsed with donor antigens promotes composite tissue allograft survival. Orthotopic hind-limb transplants were performed (day 0) from Wistar-Furth (RT1) to Lewis (RT1(u)) rats. Recipient dendritic cells were propagated from bone marrow with granulocyte-macrophage colony-stimulating factor (bone marrow-derived dendritic cells) and pulsed with or without donor splenic cell lysate. Recipients were as follows: group I, control; group II, cyclosporine (10 mg/kg/day, days 0 through 6, intraperitoneally); group III, antilymphocyte serum plus cyclosporine (days -4 and +1, intraperitoneally); and groups IV and V, cyclosporine plus antilymphocyte serum, combined with 7 x 10(6) untreated or donor cell lysate-pulsed bone marrow-derived dendritic cells (days +7 and +14, intravenously), respectively. Epidermolysis/desquamation of donor skin defined rejection. Mixed leukocyte reaction determined recipient T-cell reactivity to donor. Tissue samples were obtained at 3 weeks and on the day of rejection. Groups comprised six or seven rats. Donor alloantigen-pulsed bone marrow-derived dendritic cells (group V) significantly prolonged median composite tissue allograft survival time (32.0 days) compared with groups II (18.0 days, p = 0.0012), III (22.5 days, p = 0.0043), and IV (26.5 days, p = 0.0043). Splenic T cells in group V exhibited hyporesponsiveness to donor alloantigen in mixed leukocyte reaction. Interestingly, the graft muscle component in the bone marrow-derived dendritic cell-treated group (group V) showed significant reduction in mononuclear cell infiltration relative to group II (p = 0.0317). Donor alloantigen-pulsed recipient bone marrow-derived dendritic cells combined with transient T-cell-directed immunosuppression significantly prolonged composite tissue allograft survival across a full major histocompatibility complex barrier. This may represent the basis for a novel, clinically applicable strategy to promote composite tissue allograft survival with reduced systemic immunosuppression.
    No preview · Article · Feb 2008 · Plastic and Reconstructive Surgery
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    ABSTRACT: Considering that little is known about the peripheral nerve regenerative capacity of elderly patients, the authors studied nerve regenerative capacity in aged rats and compared the effect of three synthetic nerve guides with different material characteristics and porosity. The authors hypothesized that the use of a biodegradable composite nerve guide (CultiGuides) would promote nerve regeneration and functional recovery in a manner similar to treatment with autografts or U.S. Food and Drug Administration-approved polyglycolic acid Neurotubes in an aged rat sciatic nerve defect model. Aged Sprague-Dawley rats (11 months old) underwent a 1-cm sciatic nerve resection in the right leg [group 1, control (contralateral leg samples), n = 10; group 2, negative (nerve gap defect), n = 6; group 3, autograft, n = 10; group 4, polycaprolactone, n = 10; group 5, CultiGuides, n = 10; and group 6, Neurotube, n = 10]. After 12 weeks, the negative group did not demonstrate any nerve regeneration. In the regenerated and distal nerve, all treated groups had increased myelinated areas compared with the negative control. In the regenerated nerve, there was a significant increase in myelination in the Neurotube group compared with the polycaprolactone group (p < 0.001). However, in the distal nerve, there were no differences among the treatment groups. Walking track analyses and gastrocnemius muscle weight ratios were not different among treatment groups 3 through 6. The results showed differences in myelination; Neurotubes promoted the highest degree of myelination (p < 0.001) as compared with all groups. The authors found no improvement in function of the repaired nerve as measured by percentage of autotomy, the sciatic function index, and gastrocnemius muscle weight. No group was able to recover function in this aged model.
    No preview · Article · Jun 2007 · Plastic and Reconstructive Surgery
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    ABSTRACT: Composite tissue allografts (CTAs) contain their own reservoir of vascularized bone marrow, offering novel aspects for the induction of donor-specific tolerance. Additionally, the manipulation of recipient dendritic cells, pulsed with donor allopeptide, has been shown to engender solid organ allograft survival. To exploit these modalities, we have developed a protocol utilizing injection of recipient bone marrow-derived dendritic cells (BMDCs) pulsed with a donor-derived peptide for use in CTA transplantation. Six days prior to orthotopic hind-limb transplantation, Lewis rats received IV injection of donor allopeptide-pulsed, recipient BMDCs, in conjunction with a single dose of anti-lymphocyte serum. Control groups displayed signs of allograft rejection within 5 days postoperatively. Animals within the primary experimental cohort demonstrated prolongation of graft survival to an average of 8 days, and exhibited low numbers of donor T cells. The use of BMDCs in conjunction with transient immunosuppression has potential therapeutic application for induction of donor-antigen-specific tolerance to hind limb allografts.
    No preview · Article · Jan 2007 · Microsurgery
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    ABSTRACT: There is a need for engineered soft tissue in reconstructive surgery, particularly after tumor removal. An ideal implant that will provide structural support and a favorable environment for growing cells is a key element in the process of tissue engineering. Nonbiodegradable materials that become well incorporated within the new tissue are a good solution, but many such materials do not have a surface favorable for cell adherence and proliferation. The authors hypothesized that the modification of the pore size in a novel fluoropolymer would improve the adherence and enhance the proliferation of adipose-derived stem cells. Fluoropolymers with two varying pore size ranges were examined. Fluoropolymer compound U48 (pore size, 100 to 180 microm) and fluoropolymer compound P54 (pore size, 10 to 55 microm) were seeded with human adipose-derived stem cells, and cell adherence to the material was measured after 4 hours and cell proliferation was measured after 72 hours. Cell-seeded constructs were implanted subcutaneously in a nude mouse model for 30 days. Fluoropolymer surface treatment with fibronectin improved the attachment of adipose-derived stem cells to the well plates but did not improve attachment to the fluoropolymer, regardless of pore size. Fluoropolymer U48 increases the adherence and provides a favorable surface for proliferation of adipose-derived stem cells. After subcutaneous implantation into nude mice, tissue growth was observed in the fluoropolymer samples with the larger pore size. The characteristics of this new material will allow for future clinical applications in plastic and reconstructive surgery.
    No preview · Article · Nov 2006 · Plastic and Reconstructive Surgery
  • W P Andrew Lee · Vu T Nguyen
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    ABSTRACT: The early experience of hand transplantation has yielded a mixture of successes and failures. No life-threatening adverse effects have been encountered from immunosuppression, yet additional medications were required in some cases with unknown long-term efficacy or side effects. Limited functional returns have been observed, but any effect of chronic rejection is too early to determine. Although the experience has confirmed the benefits of hand transplantation to patients and their families, the future of hand transplantation on a wide scale is dependent on further research to alter its risk-benefit balance.
    No preview · Article · Nov 2005 · Clinics in Plastic Surgery
  • Giselle G Hamad · Vu T Nguyen · Eric J DeMaria
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    ABSTRACT: A morbidly obese female with a body mass index of 50.7 kg/m2 and comorbidities of back pain and migraine headaches was taken to the operating room for a laparoscopic Roux-en-Y gastric bypass. She was incidentally found to have intestinal malrotation. The Roux-en-Y gastric bypass was completed laparoscopically, followed by laparoscopic division of Ladd's bands, and appendectomy.
    No preview · Article · Nov 2004 · Journal of Laparoendoscopic & Advanced Surgical Techniques