An Optimized, Synthetic DNA Vaccine Encoding the Toxin A and Toxin B Receptor Binding Domains of Clostridium difficile Induces Protective Antibody Responses <i>In Vivo</i>

ABSTRACT Clostridium difficile -associated disease (CDAD) constitutes a large majority of nosocomial diarrhea cases in industrialized nations and is mediated by the effects of two secreted toxins, toxin A (TcdA) and toxin B (TcdB). Patients who develop strong antitoxin antibody responses can clear C. difficile infection and remain disease free. Key toxin-neutralizing epitopes have been found within the carboxy-terminal receptor binding domains (RBDs) of TcdA and TcdB, which has generated interest in developing the RBD as a viable vaccine target. While numerous platforms have been studied, very little data describes the potential of DNA vaccination against CDAD. Therefore, we created highly optimized plasmids encoding the RBDs from TcdA and TcdB in which any putative N -linked glycosylation sites were altered. Mice and nonhuman primates were immunized intramuscularly, followed by in vivo electroporation, and in these animal models, vaccination induced significant levels of both anti-RBD antibodies (blood and stool) and RBD-specific antibody-secreting cells. Further characterization revealed that sera from immunized mice and nonhuman primates could detect RBD protein from transfected cells, as well as neutralize purified toxins in an in vitro cytotoxicity assay. Mice that were immunized with plasmids or given nonhuman-primate sera were protected from a lethal challenge with purified TcdA and/or TcdB. Moreover, immunized mice were significantly protected when challenged with C. difficile spores from homologous (VPI 10463) and heterologous, epidemic (UK1) strains. These data demonstrate the robust immunogenicity and efficacy of a TcdA/B RBD-based DNA vaccine in preclinical models of acute toxin-associated and intragastric, spore-induced colonic disease. </jats:p

Impact of catastrophic brain injury guidelines on organ donation rates: Results of an EAST multicenter trial

BACKGROUND: One third of organ donors suffer catastrophic brain injury (CBI). There are no standard guidelines for the management of traumatic CBI prior to brain death, and not all trauma centers have institutional CBI guidelines. In addition, there is high variability in management between institutions with guidelines. Catastrophic brain injury guidelines vary and may include various combinations of hormone therapy, vasopressors, fluid resuscitation, and other practices. We hypothesized that centers with CBI guidelines have higher organ donation rates than those without. METHODS: This prospective, observational EAST-sponsored multicenter trial included adult (18+ years old) traumatic-mechanism CBI patients at 33 level I and II trauma centers from January 2022 to May 2023. Catastrophic brain injury was defined as a brain injury causing loss of function above the brain stem and subsequent death. Cluster analysis with linear mixed-effects model including UNOS regions and hospital size by bed count was used to determine whether CBI guidelines are associated with organ donation. RESULTS: A total of 790 CBI patients were included in this analysis. In unadjusted comparison, CBI guideline centers had higher rates of organ donation and use of steroids, whole blood, and hormone therapy. In a linear mixed-effects model, CBI guidelines were not associated with organ donation. Registered organ donor status, steroid hormones, and vasopressin were associated with increased relative risk of donation. CONCLUSION: There is high variability in management of CBI, even at centers with CBI guidelines in place. While the use of institutional CBI guidelines was not associated with increased organ donation, guidelines in this study were not identical. Hormone replacement with steroids and vasopressin was associated with increased donation. Hormone resuscitation is a common feature of CBI guidelines. Further analysis of individual practices that increase organ donation after CBI may allow for more effective guidelines and an overall increase in donation to decrease the long waiting periods for organ transplant recipients. LEVEL OF EVIDENCE: Prognostic; Level III

Impact of catastrophic brain injury guidelines on organ donation rates: Results of an EAST multicenter trial.

BACKGROUND: One third of organ donors suffer catastrophic brain injury (CBI). There are no standard guidelines for the management of traumatic CBI prior to brain death, and not all trauma centers have institutional CBI guidelines. In addition, there is high variability in management between institutions with guidelines. Catastrophic brain injury guidelines vary and may include various combinations of hormone therapy, vasopressors, fluid resuscitation, and other practices. We hypothesized that centers with CBI guidelines have higher organ donation rates than those without. METHODS: This prospective, observational EAST-sponsored multicenter trial included adult (18+ years old) traumatic-mechanism CBI patients at 33 level I and II trauma centers from January 2022 to May 2023. Catastrophic brain injury was defined as a brain injury causing loss of function above the brain stem and subsequent death. Cluster analysis with linear mixed-effects model including UNOS regions and hospital size by bed count was used to determine whether CBI guidelines are associated with organ donation. RESULTS: A total of 790 CBI patients were included in this analysis. In unadjusted comparison, CBI guideline centers had higher rates of organ donation and use of steroids, whole blood, and hormone therapy. In a linear mixed-effects model, CBI guidelines were not associated with organ donation. Registered organ donor status, steroid hormones, and vasopressin were associated with increased relative risk of donation. CONCLUSION: There is high variability in management of CBI, even at centers with CBI guidelines in place. While the use of institutional CBI guidelines was not associated with increased organ donation, guidelines in this study were not identical. Hormone replacement with steroids and vasopressin was associated with increased donation. Hormone resuscitation is a common feature of CBI guidelines. Further analysis of individual practices that increase organ donation after CBI may allow for more effective guidelines and an overall increase in donation to decrease the long waiting periods for organ transplant recipients. LEVEL OF EVIDENCE: Prognostic; Level III

Impact of catastrophic brain injury guidelines on organ donation rates: Results of an EAST multicenter trial.

BACKGROUND: One third of organ donors suffer catastrophic brain injury (CBI). There are no standard guidelines for the management of traumatic CBI prior to brain death, and not all trauma centers have institutional CBI guidelines. In addition, there is high variability in management between institutions with guidelines. Catastrophic brain injury guidelines vary and may include various combinations of hormone therapy, vasopressors, fluid resuscitation, and other practices. We hypothesized that centers with CBI guidelines have higher organ donation rates than those without. METHODS: This prospective, observational EAST-sponsored multicenter trial included adult (18+ years old) traumatic-mechanism CBI patients at 33 level I and II trauma centers from January 2022 to May 2023. Catastrophic brain injury was defined as a brain injury causing loss of function above the brain stem and subsequent death. Cluster analysis with linear mixed-effects model including UNOS regions and hospital size by bed count was used to determine whether CBI guidelines are associated with organ donation. RESULTS: A total of 790 CBI patients were included in this analysis. In unadjusted comparison, CBI guideline centers had higher rates of organ donation and use of steroids, whole blood, and hormone therapy. In a linear mixed-effects model, CBI guidelines were not associated with organ donation. Registered organ donor status, steroid hormones, and vasopressin were associated with increased relative risk of donation. CONCLUSION: There is high variability in management of CBI, even at centers with CBI guidelines in place. While the use of institutional CBI guidelines was not associated with increased organ donation, guidelines in this study were not identical. Hormone replacement with steroids and vasopressin was associated with increased donation. Hormone resuscitation is a common feature of CBI guidelines. Further analysis of individual practices that increase organ donation after CBI may allow for more effective guidelines and an overall increase in donation to decrease the long waiting periods for organ transplant recipients. LEVEL OF EVIDENCE: Prognostic; Level III