Analyse de l infection à staphylococcus aureus de prothèses cardio-vasculaires

L infection prothétique à Staphylococcus aureus reste un des problèmes majeurs de la chirurgie cardio-vasculaire. Cette pathologie, présente dans 5% des cas, est grevée d une lourde morbi-mortalité. L amélioration des connaissances des facteurs favorisant l adhésion bactérienne, ainsi que les moyens de lutte contre cette infection apparaissent dès lors d un intérêt majeur. Ce travail a donc porté sur l influence de l espèce bactérienne et des paramètres physico-chimiques du support, lors de l adhésion au carbone pyrolytique et au polyester, éléments constitutifs des prothèses implantées en chirurgie cardiaque. Une deuxième partie est consacrée à l étude des variations protéomiques et à l identification des protéines d intérêt du S. aureus lors de son adhésion au carbone pyrolytique, afin de découvrir de nouvelles cibles thérapeutiques. Enfin, une dernière partie est consacrée à la lutte contre l infection prothétique à S. aureus par l utilisation d allogreffes cryopréservées.Prosthetic infection with Staphylococcus aureus remains one of the major problems of the cardio-vascular surgery with a high morbidity and mortality rate. The management and the treatment of these infections remain controversial. Therefore, a better knowledge of the mechanisms involved in biomaterial adhesion is essential. The aim of this study was to analyze the interaction of surface free energy and roughness characteristics of different pyrolytic carbon heart valves with three bacterial species on biofilm formation. A second part is devoted to the study of proteomic changes occurring during adhesion of S. aureus on pyrolytic carbon and to the identification of proteins of interest. A final section focused on the treatment of S. aureus prosthetic infection with the used of cryopreserved allografts.ROUEN-BU Sciences (764512102) / SudocSudocFranceF

Human endothelial cells synthesize protein Z, but not the protein Z dependent inhibitor.

International audienceProtein Z (PZ) is a vitamin K-dependent protein isolated from human plasma, and acts as a cofactor for a serpin, called protein Z-dependent protease inhibitor (ZPI). A prothrombotic phenotype has been reported in PZ deficient mice, and PZ deficiencies have been observed in patients with arterial thrombotic events. PZ was immunologically detected in the endothelium of atherosclerotic arteries, suggesting that endothelial cells could be involved in the production of PZ. In this study we analyzed the synthesis and release of PZ and ZPI by human umbilical vein endothelial cells (HUVEC), representative of the macrovasculature, and by HMEC-1, a microvascular endothelial cell line. PZ was quantified by a specific ELISA in the supernatant and in the lysates of both cellular types. Western blotting of the supernatants showed the presence of a band of 62 kDa, identical to PZ synthesized by the hepatoma cell line HepG2. mRNA of PZ was also detected in each cellular type. PZ biosynthesis was unaffected by inflammatory cytokines in HUVEC, whereas a slight decrease of mRNA and PZ antigen (53.5 +/- 14.5% of protein synthesis as compared to the control, p < 0.01) and a modest increase (126 +/- 8.5% as compared to the control, p < 0.05) were induced respectively byTumor Necrosis Factor (TNF)-alpha (25 ng/ml) and oncostatin M (5 ng/ml) in HMEC-1. Immunological studies showed the presence of PZ near the nucleus and a possible expression of PZ at the membrane. In addition, PZ was present in the endothelial cells of both normal arterial and venous vessel sections. In contrast, neither ZPI nor its mRNA was detected in endothelial cells

Rerouting the internal thoracic pedicle: a novel solution for maxillofacial reconstruction in vessel-depleted situations? A preliminary anatomic study

International audienceMicrosurgical reconstruction in a vessel-depleted neck is a challenge due to the lack of reliable vessels in or nearby the host site. The use of the internal thoracic pedicle (ITP) by rib section or sparring is a limited option due to the small length of the pedicle of some flaps. However, in cardiac surgery, the internal thoracic artery (ITA) is widely used for myocardial revascularization, providing a long and versatile pedicle. We aimed at determining precise anatomical bases for the use of the ITP, approached by sternotomy and rerouted in the neck, as recipient vessels for free-flap facial reconstructions

Proteomic analysis of Staphylococcus aureus biofilms grown in vitro on mechanical heart valve leaflets

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Hemolysis induced by Left Ventricular Assist Device is associated with proximal tubulopathy.

BackgroundChronic subclinical hemolysis is frequent in patients implanted with Left Ventricular Assist Device (LVAD) and is associated with adverse outcomes. Consequences of LVADs-induced subclinical hemolysis on kidney structure and function is currently unknown.MethodsThirty-three patients implanted with a Heartmate II LVAD (Abbott, Inc, Chicago IL) were retrospectively studied. Hemolysis, Acute Kidney Injury (AKI) and the evolution of estimated Glomerular Filtration Rate were analyzed. Proximal Tubulopathy (PT) groups were defined according to proteinuria, normoglycemic glycosuria, and electrolytic disorders. The Receiver Operating Characteristic (ROC) curve was used to analyze threshold of LDH values associated with PT.ResultsMedian LDH between PT groups were statistically different, 688 IU/L [642-703] and 356 IU/L [320-494] in the "PT" and "no PT" groups, respectively p = 0.006. To determine PT group, LDH threshold > 600 IU/L was associated with a sensitivity of 85.7% (95% CI, 42.1-99.6) and a specificity of 84.6% (95% CI, 65.1-95.6). The ROC's Area Under Curve was 0.83 (95% CI, 0.68-0.98). In the "PT" group, patients had 4.2 [2.5-5.0] AKI episodes per year of exposure, versus 1.6 [0.4-3.7] in the "no PT" group, p = 0.03. A higher occurrence of AKI was associated with subsequent development of Chronic Kidney Disease (CKD) (p = 0.02) and death (p = 0.05).ConclusionsLVADs-induced subclinical hemolysis is associated with proximal tubular functional alterations, which in turn contribute to the occurrence of AKI and subsequent CKD. Owing to renal toxicity of hemolysis, measures to reduce subclinical hemolysis intensity as canula position or pump parameters should be systematically considered, as well as specific nephroprotective therapies

Leukocyte SPECT/CT for detecting infection of left-ventricular-assist devices: preliminary results.

International audienceWe report our experience with using integrated molecular and anatomic hybrid imaging to assess infection in patients who have a left-ventricular-assist device (LVAD). Thirteen (99m)Tc-exametazime-leukocyte planar and SPECT/CT scans were obtained for 8 consecutive patients who had an implanted LVAD. SPECT/CT was used to assess suspected device-related infections (n = 8) and to evaluate the efficiency of current antibiotic therapy (n = 5). Device-related infection was seen on 8 of the 13 scans. SPECT/CT was positive for infection in all 8 patients, whereas planar scans were positive in 6 of 8. SPECT/CT provided relevant information on the extent of infection and its exact location in all patients. Additional distant infectious foci were demonstrated in 3 of 13 patients. SPECT/CT led to an accurate diagnosis of LVAD-related infection, revealing both anatomic location and extent. This noninvasive approach could lead to improved therapeutic strategies

Leukocyte SPECT/CT for detecting infection of left-ventricular-assist devices: preliminary results.

International audienceWe report our experience with using integrated molecular and anatomic hybrid imaging to assess infection in patients who have a left-ventricular-assist device (LVAD). Thirteen (99m)Tc-exametazime-leukocyte planar and SPECT/CT scans were obtained for 8 consecutive patients who had an implanted LVAD. SPECT/CT was used to assess suspected device-related infections (n = 8) and to evaluate the efficiency of current antibiotic therapy (n = 5). Device-related infection was seen on 8 of the 13 scans. SPECT/CT was positive for infection in all 8 patients, whereas planar scans were positive in 6 of 8. SPECT/CT provided relevant information on the extent of infection and its exact location in all patients. Additional distant infectious foci were demonstrated in 3 of 13 patients. SPECT/CT led to an accurate diagnosis of LVAD-related infection, revealing both anatomic location and extent. This noninvasive approach could lead to improved therapeutic strategies

Leukocyte SPECT/CT for detecting infection of left-ventricular-assist devices: preliminary results.

International audienceWe report our experience with using integrated molecular and anatomic hybrid imaging to assess infection in patients who have a left-ventricular-assist device (LVAD). Thirteen (99m)Tc-exametazime-leukocyte planar and SPECT/CT scans were obtained for 8 consecutive patients who had an implanted LVAD. SPECT/CT was used to assess suspected device-related infections (n = 8) and to evaluate the efficiency of current antibiotic therapy (n = 5). Device-related infection was seen on 8 of the 13 scans. SPECT/CT was positive for infection in all 8 patients, whereas planar scans were positive in 6 of 8. SPECT/CT provided relevant information on the extent of infection and its exact location in all patients. Additional distant infectious foci were demonstrated in 3 of 13 patients. SPECT/CT led to an accurate diagnosis of LVAD-related infection, revealing both anatomic location and extent. This noninvasive approach could lead to improved therapeutic strategies

Biofilm formation on pyrolytic carbon heart valves: Influence of surface free energy, roughness, and bacterial species

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