Systemic calcitonin gene-related peptide receptor antagonism decreases survival in a porcine model of polymicrobial sepsis: blinded randomised controlled trial.

BACKGROUND: Calcitonin gene-related peptide (CGRP) and procalcitonin, which are overexpressed in sepsis, exert distinct immunomodulatory effects mediated through the CGRP receptor. The CGRP receptor antagonist olcegepant improves survival in murine sepsis. This study evaluated whether CGRP receptor antagonism is similarly beneficial in a porcine model of polymicrobial sepsis. METHODS: We conducted a prospective randomised, controlled, investigator-blinded trial in adult pigs of either sex, that were anaesthetised and ventilated before sepsis was induced by polymicrobial (autologous) faecal peritonitis. After the onset of early septic shock (systolic blood pressure <90 mm Hg or >10% decline from baseline MAP), pigs were resuscitated (i.v. fluid/antibiotics/vasopressors) and randomised to receive either i.v. olcegepant (n=8) or vehicle control (n=8). The primary outcome was time to death, euthanasia required up to 72 h after surgery (according to predefined severe cardiorespiratory failure), or both. Secondary outcomes included haemodynamic changes, and systemic as well as organ inflammation (mRNA expression). RESULTS: Septic shock developed 8.7 h (inter-quartile range, 5.8-11.1 h) after the onset of faecal peritonitis. Olcegepant worsened survival, with 6/8 pigs randomised to the control group surviving 72.0 h (50.9-72.0 h), compared with 3/8 pigs receiving olcegepant surviving 51.3 h (12.5-72.0 h; P=0.01). At 48 h, lower MAP and higher cardiac output occurred in pigs receiving olcegepant. Cardiac, hepatic, and renal injury was not different between pigs randomised to receive olcegepant or vehicle. Olcegepant reduced mRNA expression of several inflammation-related cytokines and CD68+ macrophages in liver but not in lung tissue. CONCLUSIONS: CGRP receptor antagonism with olcegepant was not beneficial in this porcine model of polymicrobial sepsis, which closely mimics human sepsis.

Complement C5a Functions as a Master Switch for the pH Balance in Neutrophils Exerting Fundamental Immunometabolic Effects.

During sepsis, excessive activation of the complement system with generation of the anaphylatoxin C5a results in profound disturbances in crucial neutrophil functions. Moreover, because neutrophil activity is highly dependent on intracellular pH (pHi), we propose a direct mechanistic link between complement activation and neutrophil pHi In this article, we demonstrate that in vitro exposure of human neutrophils to C5a significantly increased pHi by selective activation of the sodium/hydrogen exchanger. Upstream signaling of C5a-mediated intracellular alkalinization was dependent on C5aR1, intracellular calcium, protein kinase C, and calmodulin, and downstream signaling regulated the release of antibacterial myeloperoxidase and lactoferrin. Notably, the pH shift caused by C5a increased the glucose uptake and activated glycolytic flux in neutrophils, resulting in a significant release of lactate. Furthermore, C5a induced acidification of the extracellular micromilieu. In experimental murine sepsis, pHi of blood neutrophils was analogously alkalinized, which could be normalized by C5aR1 inhibition. In the clinical setting of sepsis, neutrophils from patients with septic shock likewise exhibited a significantly increased pHi These data suggest a novel role for the anaphylatoxin C5a as a master switch of the delicate pHi balance in neutrophils resulting in profound inflammatory and metabolic changes that contribute to hyperlactatemia during sepsis.

Complement C5a Alters the Membrane Potential of Neutrophils during Hemorrhagic Shock.

BACKGROUND: Polymorphonuclear granulocytes (PMN) play a crucial role in host defense. Physiologically, exposure of PMN to the complement activation product C5a results in a protective response against pathogens, whereas in the case of systemic inflammation, excessive C5a substantially impairs neutrophil functions. To further elucidate the inability of PMN to properly respond to C5a, this study investigates the role of the cellular membrane potential of PMN in response to C5a. METHODS: Electrophysiological changes in cellular and mitochondrial membrane potential and intracellular pH of PMN from human healthy volunteers were determined by flow cytometry after exposure to C5a. Furthermore, PMN from male Bretoncelles-Meishan-Willebrand cross-bred pigs before and three hours after severe hemorrhagic shock were analyzed for their electrophysiological response. RESULTS: PMN showed a significant dose- and time-dependent depolarization in response to C5a with a strong response after one minute. The chemotactic peptide fMLP also evoked a significant shift in the membrane potential of PMN. Acidification of the cellular microenvironment significantly enhanced depolarization of PMN. In a clinically relevant model of porcine hemorrhagic shock, the C5a-induced changes in membrane potential of PMN were markedly diminished compared to healthy littermates. Overall, these membrane potential changes may contribute to PMN dysfunction in an inflammatory environment.

Early Detection of Junctional Adhesion Molecule-1 (JAM-1) in the Circulation after Experimental and Clinical Polytrauma.

Severe tissue trauma-induced systemic inflammation is often accompanied by evident or occult blood-organ barrier dysfunctions, frequently leading to multiple organ dysfunction. However, it is unknown whether specific barrier molecules are shed into the circulation early after trauma as potential indicators of an initial barrier dysfunction. The release of the barrier molecule junctional adhesion molecule-1 (JAM-1) was investigated in plasma of C57BL/6 mice 2 h after experimental mono- and polytrauma as well as in polytrauma patients (ISS ≥ 18) during a 10-day period. Correlation analyses were performed to indicate a linkage between JAM-1 plasma concentrations and organ failure. JAM-1 was systemically detected after experimental trauma in mice with blunt chest trauma as a driving force. Accordingly, JAM-1 was reduced in lung tissue after pulmonary contusion and JAM-1 plasma levels significantly correlated with increased protein levels in the bronchoalveolar lavage as a sign for alveolocapillary barrier dysfunction. Furthermore, JAM-1 was markedly released into the plasma of polytrauma patients as early as 4 h after the trauma insult and significantly correlated with severity of disease and organ dysfunction (APACHE II and SOFA score). The data support an early injury- and time-dependent appearance of the barrier molecule JAM-1 in the circulation indicative of a commencing trauma-induced barrier dysfunction.

What factors motivate male and female Generation Z students to become engaged as peer teachers? A mixed-method study among medical and dental students in the gross anatomy course.

Peer-teaching is widely established in anatomy teaching and offers well-described advantages. Nevertheless, at Ulm University, Germany, a reduction in the number of peer teacher applicants for the dissection course was observed. This study examined factors related to the attractiveness of a position as a peer teacher for Generation Z students. Participants of the gross anatomy course were asked to evaluate factors influencing the attractiveness of a peer teacher position using a six-point Likert scale. Additionally, open-ended questions were analyzed qualitatively. Sex-specific subgroup analysis was performed comparing students of low and high motivation to apply for a tutorship. Of the 374 students who participated in this study (response rate 53%), 38% stated that they were intending to apply as peer teachers. Data indicated that students displayed intrinsic motivation to apply for a tutorship because of the opportunity to improve their anatomy knowledge and/or their pleasure in teaching. In contrast, extrinsic factors like remuneration of the tutorship and its relevance for their curriculum vitae were least important. Anatomy educators underestimated the demotivating factor of the workload associated with the tutorship and encouraged students less frequently to apply than peer teachers. Only minor sex-specific differences could be identified. Nevertheless, female students were encouraged less frequently to apply than their male peers. In summary, Generation Z students apply as peer teachers because they are enthusiastic about the task. To motivate students to commit to extracurricular activities like a tutorship, anatomy educators should actively encourage students-particularly females-more frequently to apply.

Immunopathophysiology of trauma-related acute kidney injury.

Physical trauma can affect any individual and is globally accountable for more than one in every ten deaths. Although direct severe kidney trauma is relatively infrequent, extrarenal tissue trauma frequently results in the development of acute kidney injury (AKI). Various causes, including haemorrhagic shock, rhabdomyolysis, use of nephrotoxic drugs and infectious complications, can trigger and exacerbate trauma-related AKI (TRAKI), particularly in the presence of pre-existing or trauma-specific risk factors. Injured, hypoxic and ischaemic tissues expose the organism to damage-associated and pathogen-associated molecular patterns, and oxidative stress, all of which initiate a complex immunopathophysiological response that results in macrocirculatory and microcirculatory disturbances in the kidney, and functional impairment. The simultaneous activation of components of innate immunity, including leukocytes, coagulation factors and complement proteins, drives kidney inflammation, glomerular and tubular damage, and breakdown of the blood-urine barrier. This immune response is also an integral part of the intense post-trauma crosstalk between the kidneys, the nervous system and other organs, which aggravates multi-organ dysfunction. Necessary lifesaving procedures used in trauma management might have ambivalent effects as they stabilize injured tissue and organs while simultaneously exacerbating kidney injury. Consequently, only a small number of pathophysiological and immunomodulatory therapeutic targets for TRAKI prevention have been proposed and evaluated.

H2S in acute lung injury: a therapeutic dead end(?).

This review addresses the plausibility of hydrogen sulfide (H2S) therapy for acute lung injury (ALI) and circulatory shock, by contrasting the promising preclinical results to the present clinical reality. The review discusses how the narrow therapeutic window and width, and potentially toxic effects, the route, dosing, and timing of administration all have to be balanced out very carefully. The development of standardized methods to determine in vitro and in vivo H2S concentrations, and the pharmacokinetics and pharmacodynamics of H2S-releasing compounds is a necessity to facilitate the safety of H2S-based therapies. We suggest the potential of exploiting already clinically approved compounds, which are known or unknown H2S donors, as a surrogate strategy.

The Use of a Mobile Learning Tool by Medical Students in Undergraduate Anatomy and its Effects on Assessment Outcomes.

Hand-held devices have revolutionized communication and education in the last decade. Consequently, mobile learning (m-learning) has become popular among medical students. Nevertheless, there are relatively few studies assessing students' learning outcomes using m-learning devices. This observational study presents an anatomy m-learning tool (eMed-App), an application developed to accompany an anatomy seminar and support medical students' self-directed learning of the skeletal system. Questionnaire data describe where, how frequently, and why students used the app. Multiple choice examination results were analyzed to evaluate whether usage of the app had an effect on test scores. The eMed-App application was used by 77.5% of the students, mainly accessed by Android smartphones, and at students' homes (62.2%) in order to prepare themselves for seminar sessions (60.8%), or to review learning content (67%). Most commonly, students logged on for less than 15 minutes each time (67.8%). Frequent app users showed better test results on items covering eMed-App learning content. In addition, users also achieved better results on items that were not related to the content of the app and, thus, gained better overall test results and lower failure rates. The top quartile of test performers used the eMed-App more frequently compared to students in lower quartiles. This study demonstrated that many students, especially the high-performing ones, made use of the eMed-App. However, the app itself did not result in better outcomes, suggesting that top students might have been more motivated to use the app than students who were generally weak in anatomy.

Anonymous body or first patient? A status report and needs assessment regarding the personalization of donors in dissection courses in German, Austrian, and Swiss Medical Schools.

Many Anglo-American universities have undertaken a paradigm shift in how the dissection of human material is approached, such that students are encouraged to learn about the lives of body donors, and to respectfully "personalize" them as human beings, rather than treating the specimens as anonymous cadavers. For the purposes of this study, this provision of limited personal information regarding the life of a body donor will be referred to as "personalization" of body donors. At this time, it is unknown whether this paradigm shift in the personalization of body donors can be translated into the German-speaking world. A shift from donor anonymity to donor personalization could strengthen students' perception of the donor as a "first patient," and thereby reinforce their ability to empathize with their future patients. Therefore, this study aimed to collect data about the current status of donation practices at German-speaking anatomy departments (n = 44) and to describe the opinions of anatomy departments, students (n = 366), and donors (n = 227) about possible donor personalization in medical education. Anatomy departments in Germany, Austria, and Switzerland were invited to participate in an online questionnaire. One-tenth of registered donors at Ulm University were randomly selected and received a questionnaire (20 items, yes-no questions) by mail. Students at the University of Ulm were also surveyed at the end of the dissection course (31 items, six-point Likert-scale). The majority of students were interested in receiving additional information about their donors (78.1%). A majority of donors also supported the anonymous disclosure of information about their medical history (92.5%). However, this information is only available in about 28% of the departments surveyed and is communicated to the students only irregularly. Overall, 78% of anatomy departments were not in favor of undertaking donor personalization. The results appear to reflect traditional attitudes among anatomy departments. However, since students clearly preferred receiving additional donor information, and most donors expressed a willingness to provide this information, one could argue that a change in attitudes is necessary. To do so, official recommendations for a limited, anonymous personalization of donated cadaveric specimens might be necessary. Anat Sci Educ 11: 282-293. © 2017 American Association of Anatomists.

Early structural changes of the heart after experimental polytrauma and hemorrhagic shock.

Evidence is emerging that systemic inflammation after trauma drives structural and functional impairment of cardiomyocytes and leads to cardiac dysfunction, thus worsening the outcome of polytrauma patients. This study investigates the structural and molecular changes in heart tissue 4 h after multiple injuries with additional hemorrhagic shock using a clinically relevant rodent model of polytrauma. We determined mediators of systemic inflammation (keratinocyte chemoattractant, macrophage chemotactic protein 1), activated complement component C3a and cardiac troponin I in plasma and assessed histological specimen of the mouse heart via standard histomorphology and immunohistochemistry for cellular and subcellular damage and ongoing apoptosis. Further we investigated spatial and quantitative changes of connexin 43 by immunohistochemistry and western blotting. Our results show significantly increased plasma levels of both keratinocyte chemoattractant and cardiac troponin I 4 h after polytrauma and 2 h after induction of hypovolemia. Although we could not detect any morphological changes, immunohistochemical evaluation showed increased level of tissue high-mobility group box 1, which is both a damage-associated molecule and actively released as a danger response signal. Additionally, there was marked lateralization of the cardiac gap-junction protein connexin 43 following combined polytrauma and hemorrhagic shock. These results demonstrate a molecular manifestation of remote injury of cardiac muscle cells in the early phase after polytrauma and hemorrhagic shock with marked disruption of the cardiac gap junction. This disruption of an important component of the electrical conduction system of the heart may lead to arrhythmia and consequently to cardiac dysfunction.