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S M Ensminger

Publications and source records attributed to S M Ensminger.

7 recordsLinked to original sources
PubMed2005

The use of preoperative intra-aortic balloon pump in open heart surgery.

AIM: Intra-aortic balloon pump (IABP) therapy before open heart surgery has been suggested for ''high risk'' patients. METHODS: Records from patients undergoing open heart surgery at our institution between June 1999 and February 2002 were reviewed. Indication for IABP insertion was severely impaired left ventricular function, acute myocardial infarction (MI) or unstable angina. RESULTS: Fifty-five patients were included in the study: 41 male, 14 female, age 64+/-9 years. Fifty-one (92.7%) required coronary artery bypass brafting (CABG) alone or as a combined procedure, 2 (3.6%) required mitral valve surgery, and 2 (3.6%) needed more complex cardiac procedures. Thirty-two patients (58%) underwent emergency cardiac surgery and 11 patients (20%) suffered from acute preoperative MI. The overall 30 days mortality was 9%. Mean intensive care unit (ICU) stay was 6+/-8 days. Four patients (7.2%) developed postoperative renal failure requiring temporary hemodialysis. Three patients (5.4%) developed IABP related peripheral vascular complications. CONCLUSIONS: Perioperative morbidity and mortality is increased despite preoperative IABP, particularly in patients with acute MI. In contrast to studies not using this approach, preoperative IABP reduces morbidity and mortality of high risk patients. IABP related complications are low. Our data suggest that high risk patients profit from preoperative IABP therapy, however, prospective studies are needed to confirm these findings.

Cardiac Surgical Procedures↗
PubMed2001

Critical role for IL-4 in the development of transplant arteriosclerosis in the absence of CD40-CD154 costimulation.

Blockade of the CD40-CD154 pathway can inhibit CD4(+) T cell activation but is unable to prevent immune responses mediated by CD8(+) T cells. However, even in the absence of CD8(+) T cells, inhibition of the CD40-CD154 pathway is insufficient to prevent the development of transplant arteriosclerosis. This study investigated the mechanisms of transplant arteriosclerosis in the absence of the CD40 pathway. C57BL/6 CD40(-/-) (H2(b)) recipients were transplanted with MHC-mismatched BALB/c (H2(d)) aortas. Transplant arteriosclerosis was evident in both CD40(-/-) and CD40(+/-) mice (intimal proliferation was 59 +/- 5% for CD40(-/-) mice vs 58 +/- 4% for CD40(+/-) mice) in the presence or absence of CD8(+) T cells (intimal proliferation was 46 +/- 7% for CD40(-/-) anti-CD8-treated mice vs 50 +/- 10% for CD40(+/-) anti-CD8-treated mice), confirming that CD8(+) T cells are not essential effector cells for the development of this disease. In CD40(-/-) recipients depleted of CD8(+) T cells, the number of eosinophils infiltrating the graft was markedly increased (109 +/- 24 eosinophils/grid for CD40(-/-) anti-CD8-treated mice vs 28 +/- 7 for CD40(+/-) anti-CD8-treated mice). The increased presence of eosinophils correlated with augmented intragraft production of IL-4. To test the hypothesis that IL-4 was responsible for the intimal proliferation, CD8 T cell-depleted CD40(-/-) recipients were treated with anti-IL-4 mAb. This resulted in significantly reduced eosinophil infiltration into the graft (12 +/- 5 eosinophils/grid for CD40(-/-) anti-CD8(+), anti-IL-4-treated mice vs 109 +/- 24 for CD40(-/-) anti-CD8-treated mice), intragraft eotaxin, CCR3 mRNA production, and the level of intimal proliferation (18 +/- 5% for CD40(-/-) anti-CD8(+)-, anti-IL-4-treated mice vs 46 +/- 7% for CD40(-/-) anti-CD8-treated mice). In conclusion, elevated intragraft IL-4 production results in an eosinophil infiltrate and is an important mechanism for CD8(+) T cell-independent transplant arteriosclerosis in the absence of CD40-CD154 costimulation.

Animals↗
PubMed2000

Intragraft interleukin-4 mRNA expression after short-term CD154 blockade may trigger delayed development of transplant arteriosclerosis in the absence of CD8+ T cells.

BACKGROUND: It has recently been shown that, although anti-CD154 induces CD4+ T-cell tolerance, it is unable to prevent allograft rejection mediated by CD8+ T cells. We have also shown that anti-CD154 monotherapy does not protect the graft from the development of transplant arteriosclerosis even in the absence of CD8+ T cells. This study was designed to investigate and characterize possible mechanisms responsible for the development of transplant arteriosclerosis after CD154 blockade in the absence of CD8+ T cells. METHODS: C57BL/6 (H2b) recipients received a fully MHC-mismatched BALB/c donor aorta (H2d). Animals were either treated with anti-CD154 monoclonal antibody (mAb) in the presence or absence of CD8 T cells. Histology, morphometric measurements, immunohistochemistry, and the production of alloantibodies (IgM, IgG1, IgG2a) were analyzed on days 14, 30, and 50 after transplantation. Cytokine production within the graft was investigated by competitive reverse transcription-polymerase chain reaction on day 14. RESULTS: Combined treatment with anti-CD154 and a depleting CD8 mAb resulted in a delay in the development of transplant arteriosclerosis (intimal proliferation: 33+/-10% vs. 67+/-11% untreated control, day 30) but ultimately did not prevent its progression (intimal proliferation: 55+/-10% vs. 78+/-9% untreated control, day 50). Although there was a significant decrease in the number of CD4+, CD11b+, and CD40+ graft-infiltrating cells and a reduction in the formation of donor-specific IgG1 alloantibodies in recipients treated with anti-CD154 and anti-CD8 mAbs, mRNA for interleukin (IL)-4 was increased, suggesting a shift in the intragraft cytokine profile towards a Th2-like pattern. CONCLUSIONS: Our data provide evidence that short-term CD154 blockade is insufficient to prevent transplant arteriosclerosis, even in combination with CD8+ T-cell depletion. Moreover, the increased expression of the Th2 cytokine interleukin-4 within the graft may be responsible for the development of transplant arteriosclerosis in the long term.

Animals↗
PubMed2000

CD8+ T cells contribute to the development of transplant arteriosclerosis despite CD154 blockade.

BACKGROUND: The CD40-CD154 receptor-ligand pair plays a critical role in allograft rejection by mediating the activation of endothelial cells, antigen-presenting cells, and T cells. Blockade of this interaction prevents acute allograft rejection and leads to prolonged allograft survival in numerous experimental models, but in most cases indefinite graft survival is not achieved due to evolving transplant arteriosclerosis. In this study, we have used a model of transplant arteriosclerosis to investigate whether CD4+ and CD8+ T cells are differentially affected by CD154 blockade. METHODS: BALB/c (H2d) aortic grafts were transplanted into C57BL/6 (H2b) recipients treated with anti-CD154 monoclonal antibody in the presence or absence of CD8+ T-cell depletion. Histology and morphometric measurements were performed on day 30 after transplantation. RESULTS: Only combined treatment with anti-CD154 and anti-CD8 monoclonal antibodies resulted in a significant reduction of intimal proliferation (33 +/-10% vs. 67+/-14%; untreated control). Administration of either antibody alone did not produce this effect. Thymectomy did not alter the degree of intimal proliferation observed in any of the treatment groups. CONCLUSIONS: Our data provide direct evidence that CD8+ T cells are not targeted effectively by CD154 blockade and that the transplant arteriosclerosis seen after CD154 blockade is not due to recent thymic emigrant T cells.

Animals↗
PubMed2000

Development of a combined cardiac and aortic transplant model to investigate the development of transplant arteriosclerosis in the mouse.

BACKGROUND: The degree of transplant arteriosclerosis in murine cardiac allografts is difficult to assess. Aortic allografts represent an alternative model for evaluating the impact of novel transplant strategies on transplant arteriosclerosis in which the vascular changes can be quantified easily. However, it remains controversial as to whether vascular lesions seen in this model are equivalent to those that develop in solid-organ transplants. The aim of this study was to develop a model of combined cardiac and aortic transplantation to allow more precise quantification of transplant arteriosclerosis and to establish a correlation between the lesions that develop in the 2 types of graft. METHODS: CBA (H2(k)) recipients received a C57BL/10 (H2(b)) cervical cardiac allograft on Day 0 and a C57BL/10 (H2(b)) abdominal aortic allograft on Day 1. Recipients were treated with anti-CD154 mAb (MR1) on Days 0, 2, and 4. We performed histology and morphometric measurements for both grafts 30 days after transplantation. RESULTS: We observed significant intimal proliferation in both the cervical cardiac and abdominal aortic allografts from recipients treated with anti-CD154 mAb (heart, 64% +/- 9%; aorta, 67% +/- 8%; n = 5). Abdominal aortic grafts transplanted alone into anti-CD154-treated recipients developed a degree of transplant arteriosclerosis equivalent to that seen in the aortic grafts of the combined group (aorta alone, 68% +/- 9%, vs aorta + heart, 67% +/- 8%; n = 5). CONCLUSIONS: This combined cardiac and aortic transplant model permitted quantitative assessment of transplant arteriosclerosis while monitoring graft survival by cardiac palpation. Furthermore, development of transplant arteriosclerosis was equivalent in abdominal aortic allografts either in the presence or absence of an additional solid- organ transplant.

Animals↗