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SummaryIt is unknown what the spatial boundaries of tissue response to wounding are. Here we show that in mammals the ribosomal protein S6 (rpS6) is phosphorylated in response to skin injury forming a zone of activation surrounding the region of the initial insult. This p-rpS6-zone forms within minutes after wounding and is present until healing is complete. The zone encapsulates markers of the healing process, including proliferation, senescence, and angiogenesis in wounded skin. A mouse model unable to phosphorylate rpS6 shows an initial acceleration of wound closure, but results in disrupted healing. Finally, the p-rpS6-zone accurately reports on the status of dermal vasculature and the effectiveness of healing. In summary, the zone divides an otherwise homogenous tissue into regions with distinct properties.

Cecal ligation and puncture (CLP) is referred to as the "gold standard" rodent model for abdominal sepsis. CLP creates a continuously leaking, polymicrobial infectious focus in the abdomen. The abdominal cavity is opened under general anesthesia and analgesia and the cecum is exposed, ligated underneath the ileocecal valve, and punctured with a needle. A small amount of feces is pressed out through the puncture and the cecum is repositioned into the abdomen, which is then closed with single button sutures and tissue glue. CLP severity can be influenced via the length of the ligated cecum as well as the needle size. Within 24 h, animals develop clinical signs of a systemic bacterial infection. Analgesia, wide range antibiotic treatment, and fluid resuscitation should be administered during the acute phase of sepsis to increase the clinical relevance of the CLP model.

Cecal ligation and puncture (CLP) is referred to as the "gold standard" rodent model for abdominal sepsis. CLP creates a continuously leaking, polymicrobial infectious focus in the abdomen. The abdominal cavity is opened under general anesthesia and analgesia and the cecum is exposed, ligated underneath the ileocecal valve, and punctured with a needle. A small amount of feces is pressed out through the puncture and the cecum is repositioned into the abdomen, which is then closed with single button sutures and tissue glue. CLP severity can be influenced via the length of the ligated cecum as well as the needle size. Within 24 h, animals develop clinical signs of a systemic bacterial infection. Analgesia, wide range antibiotic treatment, and fluid resuscitation should be administered during the acute phase of sepsis to increase the clinical relevance of the CLP model.

Rapidly evolving multidrug resistance renders conventional antimicrobial strategies increasingly inefficient. This urges the exploration of alternative strategies with a lower potential of resistance development to control microbial infections. A promising option is antimicrobial photodynamic therapy (aPDT), especially in the setting of wound infections. In this study its effectiveness was tested as a treatment option for polymicrobially infected wounds in both in vitro and in vivo models. First, aPDT was applied to wound-relevant Gram-positive and Gram-negative bacteria in planktonic culture as the standard in vitro test system and compared different media to show a possible dependency of the therapy on the surrounding environment. In a second step, aPDT was investigated in an in vitro model mimicking the wound bed conditions using fibrin-coated culture plates. Finally, we tested aPDT in vivo in a polymicrobial infected wound healing model in immunocompromised BALB/c mice. In vitro, it was shown that the bactericidal effectiveness of aPDT was strongly dependent on the surrounding environment of the phototoxic reaction. In vivo, the significant delay in wound healing induced by polymicrobial infection was drastically diminished by a two-times application of aPDT using 100 μM methylene blue (generally regarded as safe for topical application on human skin) and 24 J cm−2 pulsed red LED light. Our experiments suggest that aPDT is capable of significantly improving wound healing also in complicated polymicrobially infected wound situations.

Fibroblast growth factor-23 (FGF23), a bone-produced hormone, plays a critical role in mineral homeostasis. Human diseases associated with excessive intact circulating FGF23 (iFGF23) result in hypophosphatemia and low vitamin D hormone in patients with normal kidney function. In addition, there is accumulating evidence linking FGF23 with inflammation. Based on these studies and the frequent observation of hypophosphatemia among septic patients, we sought to elucidate further the relationship between FGF23 and mineral homeostasis in a clinically relevant murine polymicrobial sepsis model. Medium-severity sepsis was induced by cecum ligation puncture (CLP) in adult CD-1 mice of both sexes. Healthy CD-1 mice (without CLP) were used as controls. Forty-eight hours post-CLP, spontaneous urine was collected, and serum, organs and bones were sampled at necropsy. Serum iFGF23 increased ~20-fold in CLP compared to control mice. FGF23 protein concentration was increased in the bones, but not in spleen or liver of CLP mice. Despite the ~20-fold iFGF23 increase, we did not observe any significant changes in mineral homeostasis or parathyroid hormone levels in the blood of CLP animals. Urinary excretion of phosphate, calcium, and sodium remained unchanged in male CLP mice, whereas female CLP mice exhibited lower urinary calcium excretion, relative to healthy controls. In line with renal FGF23 resistance, expression of phosphate-, calcium- and sodium-transporting proteins did not show consistent changes in the kidneys of male and female CLP mice. Renal expression of the co-receptor αKlotho was downregulated in female, but not in male CLP mice. In conclusion, our data demonstrate that the dramatic, sex-independent rise in serum iFGF23 post-CLP was mainly caused by an upregulation of FGF23 secretion in the bone. Surprisingly, the upsurge in circulating iFGF23 did not alter humoral mineral homeostasis in the acutely septic mice. Hence, the biological function of elevated FGF23 in sepsis remains unclear and warrants further studies.

Immunocompromised patients are predisposed to chronically infected wounds. Especially ulcers in the dorsal region often experience secondary polymicrobial infections. However, current wound infection models mostly use single-strain bacteria. To mimic clinically occurring infections caused by fecal contamination in immunocompromised/immobile patients, which differ significantly from single-strain infections, the present study aimed at the establishment of a new mouse model using infection by fecal bacteria. Dorsal circular excision wounds in immunosuppressed mice were infected with fecal slurry solution in several dilutions up to 1:8,000. Impact of immunosuppressor, bacterial load and timing on development of wound infections was investigated. Wounds were analyzed by scoring, 3D imaging and swab analyses. Autofluorescence imaging was not successful. Dose-finding of cyclophosphamide-induced immunosuppression was necessary for establishment of bacterial wound infections. Infection with fecal slurry diluted 1:166 to 1:400 induced significantly delayed wound healing (p

This paper deals with the synthesis and investigation of comb-like poly(norbornene)s carrying lateral rod-like aramid groups. Two types of norbornene-based monomers were synthesized and copolymerized with a norbornene carrying an aliphatic side chain using ring opening metathesis polymerization (ROMP). The new monomers contain aramid derivatives that display different types of non-covalent interactions. The first monomer contains linear tri(p-benzamide)s, which exhibit the typical H-bonds that aramids are known for. The second monomer features tri(p-benzamide)s with bulky ethylhexyloxy side-chains, which suppress intermolecular hydrogen bonding and favor π–π-stacking. The monomers were copolymerized in various ratios and the influence of the composition on the material properties was investigated using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), and powder X-ray diffraction (XRD) experiments. The results show that the glass transition temperature increases proportionally with the concentration of the H-bonding monomer.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. It remains a highly lethal condition in which current tools for early diagnosis and therapeutic decision-making are far from ideal. Extracellular vesicles (EVs), 30 nm to several micrometers in size, are released from cells upon activation and apoptosis and express membrane epitopes specific for their parental cells. Since their discovery two decades ago, their role as biomarkers and mediators in various diseases has been intensively studied. However, their potential importance in the sepsis syndrome has gained attention only recently. Sepsis and EVs are both complex fields in which standardization has long been overdue. In this review, several topics are discussed. First, we review current studies on EVs in septic patients with emphasis on their variable quality and clinical utility. Second, we discuss the diagnostic and therapeutic potential of EVs as well as their role as facilitators of cell communication via micro RNA and the relevance of micro-organism-derived EVs. Third, we give an overview over the potential beneficial but also detrimental roles of EVs in sepsis. Finally, we focus on the role of EVs in selected intensive care scenarios such as coagulopathy, mechanical ventilation and blood transfusion. Overall, the prospect for EV use in septic patients is bright, ranging from rapid and precise (point-of-care) diagnostics, prevention of harmful iatrogenic interventions, to using EVs as guides of individualized therapy. Before the above is achieved, however, the EV research field requires reliable standardization of the current methods and development of new analytical procedures that can close the existing technological gaps.

The original version of this article unfortunately contained mistakes. The Tables 1–3 were missing. The correct versions of Tables 1, 2 and 3 are given below. Bettina Standhartinger was unfortunately not correctly named in the acknowledgments of the original version of this article. The correct acknowledgements are as follows: The authors would like to thank Bettina Standhartinger for her valuable assistance in organizing the Wiggers–Bernard Conference.

Sepsis remains a major challenge in translational research given its heterogeneous pathophysiology and the lack of specific therapeutics. The use of humanized mouse chimeras with transplanted human hematopoietic cells may improve the clinical relevance of pre-clinical studies. However, knowledge of the human immuno-inflammatory response during sepsis in humanized mice is scarce; it is unclear how similar or divergent mouse and human-origin immuno-inflammatory responses in sepsis are. In this study, we evaluated the early outcome-dependent immuno-inflammatory response in humanized mice generated in the NSG strain after cecal ligation and puncture (CLP) sepsis. Mice were observed for 32 h post-CLP and were assigned to either predicted-to-die (P-DIE) or predicted-to-survive (P-SUR) groups for retrospective comparisons. Blood samples were collected at baseline, 6 and 24 h, whereas the bone marrow and spleen were collected between 24 and 32 h post-CLP. In comparison to P-SUR, P-DIE humanized mice had a 3-fold higher frequency of human splenic monocytes and their CD80 expression was reduced by 1.3-fold; there was no difference in the HLA-DR expression. Similarly, the expression of CD80 on the bone marrow monocytes from P-DIE mice was decreased by 32% (p < 0.05). Sepsis induced a generalized up-regulation of both human and murine plasma cytokines (TNFα, IL-6, IL-10, IL-8/KC, MCP-1); it was additionally aggravated in P-DIE vs. P-SUR. Human cytokines were strongly overridden by the murine ones (approx. ratio 1:9) but human TNFα was 7-fold higher than mouse TNFα. Interestingly, transplantation of human cells did not influence murine cytokine response in NSG mice, but humanized NSG mice were more susceptible to sepsis in comparison with NSG mice (79 vs. 33% mortality; p < 0.05). In conclusion, our results show that humanized mice reflect selected aspects of human immune responses in sepsis and therefore may be a feasible alternative in preclinical immunotherapy modeling.

Pre-clinical animal studies are mandatory before new treatments can be tested in clinical trials. However, their use in developing new therapies for sepsis has been controversial because of limitations of the models and inconsistencies with the clinical conditions. In consideration of the revised definition for clinical sepsis and septic shock (Sepsis-3), a Wiggers-Bernard Conference was held in Vienna in May 2017 to propose standardized guidelines on pre-clinical sepsis modeling. The participants conducted a literature review of 260 most highly cited scientific articles on sepsis models published between 2003 and 2012. The review showed, for example, that mice were used in 79% and euthanasia criteria were defined in 9% of the studies. Part I of this report details the recommendations for study design and humane modeling endpoints that should be addressed in sepsis models. The first recommendation is that survival follow-up should reflect the clinical time course of the infectious agent used in the sepsis model. Furthermore, it is recommended that therapeutic interventions should be initiated after the septic insult replicating clinical care. To define an unbiased and reproducible association between a new treatment and outcome, a randomization and blinding of treatments as well as inclusion of all methodological details in scientific publications is essential. In all pre-clinical sepsis studies, the high standards of animal welfare must be implemented. Therefore, development and validation of specific criteria for monitoring pain and distress, and euthanasia of septic animals, as well as the use of analgesics are recommended. A set of four considerations is also proposed to enhance translation potential of sepsis models. Relevant biological variables and co-morbidities should be included in the study design and sepsis modeling should be extended to mammalian species other than rodents. Additionally, the need for source control (in case of a defined infection focus) should be considered. These recommendations and considerations are proposed as “best practices” for animal models of sepsis that should be implemented.

Background: Pre-clinical animal studies precede the majority of clinical trials. While the clinical definitions of sepsis and recommended treatments are regularly updated, a systematic review of pre-clinical models of sepsis has not been done and clear modeling guidelines are lacking. Objective: To address this deficit, a Wiggers-Bernard Conference on pre-clinical sepsis modeling was held in Vienna in May 2017. The goal of the conference was to identify limitations of pre-clinical sepsis models and to propose a set of guidelines, defined as the "Minimum Quality Threshold in Pre-Clinical Sepsis Studies" (MQTiPSS), to enhance translational value of these models. Methods: A total of 31 experts from 13 countries participated and were divided into 6 thematic working groups (WG): (1) study design, (2) humane modeling, (3) infection types, (4) organ failure/dysfunction, (5) fluid resuscitation, and (6) antimicrobial therapy endpoints. As basis for the MQTiPSS discussions, the participants conducted a literature review of the 260 most highly cited scientific articles on sepsis models (2002-2013). Results: Overall, the participants reached consensus on 29 points; 20 at "recommendation" (R) and 9 at "consideration" (C) strength. This executive summary provides a synopsis of the MQTiPSS consensus (Tables 1, 2, and 3). Detailed commentaries to all Rs and Cs are simultaneously published in three separate full-length papers. Conclusions: We believe that these recommendations and considerations will serve to bring a level of standardization to pre-clinical models of sepsis and ultimately improve translation of pre-clinical findings. These guideline points are proposed as "best practices" for animal models of sepsis that should be implemented. In order to encourage its wide dissemination, this article is freely accessible in Shock, Infection and Intensive Care Medicine Experimental.

Herein we report the facile synthesis of an amphiphilic rod–coil block copolymer obtained by the coupling of an amine-terminated poly(dimethylpropylamine norbornene imide) (PDMAPNI) and a pentafluorophenol ester-terminated poly(dimethoxybenzylp-aminobenzoate) (PAram). Postpolymerization amide N-deprotection of the block copolymer yielded a strongly aggregating water-soluble rod–coil copolymer. Transmission electron microscopy revealed the formation of large ribbonlike aggregates with sizes up to 50 nm in thickness and 300 nm in length.

Summary Background The role of plasminogen activator inhibitor type-1 (PAI-1) in abdominal sepsis remains elusive. Objectives To study the influence of inhibition and over-expression of PAI-1 upon survival in cecal ligation and puncture (CLP) sepsis. Methods (i) Mice underwent moderate CLP and received 10 mg kg−1 of either monoclonal anti-PAI-1 (MA-MP6H6) or control (MA-Control) antibody intravenously at 0, 18 or 30 h post-CLP. The 30-h treatment group was additionally stratified into mice predicted to survive (P-SUR) or die (P-DIE) based on IL 6 measured at 24 h post-CLP. (ii) PAI-1 expression was induced with pLIVE.PAI-1 plasmid administered 72 h pre-CLP. Blood was sampled for 5 days and survival was monitored for 28 days. Results MA-MP6H6 effectively neutralized active PAI-1 and fully restored fibrinolysis while PAI-1 over-expression was liver-specific and correlated with PAI-1 increase in the blood. Without stratification, MA-MP6H6 co-/post-treatment conferred no survival benefit. Prospective stratification (IL-6 cut-off: 14 ng mL−1) suggested increased mortality by MA-MP6H6 treatment in P-SUR that reached 30% difference (vs. MA-Control; P

Background: Regardless of whether alone or in combination, cecal ligation and puncture (CLP) is the most commonly used model to emulate human polymicrobial sepsis. Numerous CLP studies have shown that female mice survive better than males. In adult mice, this effect may be partly due to the unequal cecum mass (larger in males), as cecum ligation is frequently not size standardized. Comparing two ligation approaches, we investigated whether cecum size influences gender-specific outcome differences. Methods: 15-month-old (middle-aged) female and male CD-1 mice underwent sublethal trauma/hemorrhage followed by CLP 48 h later. The evaluation of cecum size (in centimeters) and filling (score) was immediately followed by two ligation protocols: (1) ileocecal ligation (IC-L; n = 28/each gender) below the ileocecal valve, and (2) apex ligation (AP-L; n = 31 males, n = 24 females) 2 cm from the apex ceci - all followed by an identical double puncture and 10-day monitoring. Results: Cecum length (3.4 cm in males vs. 2.65 cm in females) and filling (2.5 score points in males vs. 1.7 in females; both p < 0.05) were always greater in male than female mice (27 vs. 44%, respectively). Compared to AP-L, the 10-day CLP mortality was higher with IC-L (86% in males and 61% in females), and this exacerbation was similar in both genders (by 21% in male and 23% in female mice). Finally, the intergender comparison demonstrated that female mice displayed a significant and similar survival advantage regardless of the ligation approach: the difference reached 25% with IC-L and 24% with AP-L. Conclusions: Standardization by AP-L did not eliminate the gender-specific difference in mortality due to posttraumatic sepsis. The greater cecum length/filling in middle-aged male mice was not responsible for their inferior survival compared to females.

Mitochondrial-derived reactive oxygen species have been deemed an important contributor in sepsis pathogenesis. We investigated whether two mitochondria-targeted antioxidants (mtAOX; SkQ1 and MitoTEMPO) improved long-term outcome, lessened inflammation, and improved organ homeostasis in polymicrobial murine sepsis. 3-month-old female CD-1 mice (n=90) underwent cecal ligation and puncture (CLP) and received SkQ1 (5 nmol/kg), MitoTEMPO (50 nmol/kg), or vehicle 5 times post-CLP. Separately, 52 SkQ1-treated CLP mice were sacrificed at 24 h and 48 h for additional endpoints. Neither MitoTEMPO nor SkQ1 exerted any protracted survival benefit. Conversely, SkQ1 exacerbated 28-day mortality by 29%. CLP induced release of 10 circulating cytokines, increased urea, ALT, and LDH, and decreased glucose but irrespectively of treatment. Similar occurred for CLP-induced lymphopenia/neutrophilia and the NO blood release. At 48 h post-CLP, dying mice had approximately 100-fold more CFUs in the spleen than survivors, but this was not SkQ1 related. At 48 h, macrophage and granulocyte counts increased in the peritoneal lavage but irrespectively of SkQ1. Similarly, hepatic mitophagy was not altered by SkQ1 at 24 h. The absence of survival benefit of mtAOX may be due to the extended treatment and/or a relatively moderate-risk-of-death CLP cohort. Long-term effect of mtAOX in abdominal sepsis appears different to sepsis/inflammation models arising from other body compartments.

Ageing is a complex multifactorial process that results in many changes in physiological changes processes that ultimately increase susceptibility to a wide range of diseases. As such an ageing population is resulting in a pressing need for more and improved treatments across an assortment of diseases. Such treatments can come from a better understanding of the pathogenic pathways which, in turn, can be derived from models of disease. Therefore the more closely the model resembles the disease situation the more likely relevant the data will be that is generated from them. Here we review the state of knowledge of mouse models of a range of diseases and aspects of an ageing physiology that are all germane to ageing. We also give recommendations on the most common mouse models on their relevance to the clinical situations occurring in aged patients and look forward as to how research in ageing models can be carried out. As we continue to elucidate the pathophysiology of disease, often through mouse models, we also learn what is needed to refine these models. Such factors can include better models, reflecting the ageing patient population, or a better phenotypic understanding of existing models.

Background The mechanisms of sepsis mortality remain undefined. While there is some evidence of organ damage, it is not clear whether this damage alone is sufficient to cause death. Therefore, we aimed to examine contribution of organ injury/dysfunction to early deaths in the mouse abdominal sepsis. Methods Female OF-1 mice underwent either medium-severity cecal ligation and puncture (CLP-Only) or non-lethal CLP-ODam (CLP with cisplatin/carbontetrachloride to induce survivable hepatotoxicity and nephrotoxicity). In the first experiment, blood was collected daily from survivors (SUR; CLP-Only and CLP-ODam groups) or until early death (DIED; CLP-Only). In the second experiment (CLP-Only), early outcome was prospectively predicted based on body temperature (BT) and pairs of mice predicted to survive (P-SUR) and die (P-DIE) were sacrificed post-CLP. The overall magnitude of organ injury/dysfunction was compared in retrospectively and prospectively stratified mice. Results At day 7 post-CLP, survival in CLP-Only was 48%, while CLP-ODam was non-lethal. In CLP-Only mice within 24 h of death, urea increased to 78 (versus 40 mg/dl in SUR), ALT to 166 (vs. 108 U/l), LDH to 739 (vs. 438 U/l) and glucose declined to 43 (vs. 62 mg/dl). In CLP-ODam, hypoglycemia was exacerbated (by 1.5-fold) and ALT and LDH were 20- and 8-fold higher versus DIED (CLP-Only) mice. In CLP-Only, predicted deaths (P-DIE) were preceded by a significant rise only in cystatin C (268 vs. 170 ng/ml in P-SUR) but not in creatinine and troponin I. Respiratory function of mitochondria in the liver and kidney of P-SUR and P-DIE CLP-Only mice was not impaired (vs. controls) and ATP level in organs remained similar among all groups. Histologic injury scores in the liver, kidney, heart and lung showed no major disparities among dying, surviving and control mice. Conclusions In CLP-Only mice, although the deregulation of parameters indicative of organ injury/dysfunction was greater in dying versus surviving mice, it never exceeded the changes in surviving CLP-ODam animals, and it was not followed by histopathological damage and/or mitochondrial dysfunction. This shows that interpretation of the contribution of the organ injury/dysfunction to early deaths in the CLP model is not straightforward and depends on the pathophysiological origin of the profiled disturbances.

Gender-oriented studies in shock, trauma, and/or sepsis require accurate monitoring of hormonal fluctuations as estrogens may influence various end points. Yet, monitoring is challenging in small laboratory animals: e.g., despite its subjectivity, vaginal smears are the major method for determination of estrus cycle phases in mice. Using female mice of different age, we aimed to (a) characterize general age-related changes in systemic estrogens and (b) examine the utility of determination of the estrus cycle by vaginal smears and/or impedance simultaneously comparing them with oscillation of systemic estrogens. In this study, 3-, 15-, and 20-month-old mice underwent vaginal smear and impedance examination each morning for 22 days. Ten hours after each morning checkup, feces were collected, and a second vaginal smear performed. Blood was collected on days 15 and 22. In 3-month-old females, estrus (by smears) was three times more frequent than in older mice, but mean concentrations of plasma and fecal estrogens never decreased with age. Collectively (not individually) plotted fecal estrogens values increased in the proestrus/estrus interphase (by smears) in 3-month-old mice only. Impedance typically peaked (4.5 Ω in 3-month-old mice) in the estrus phase, and only the prediction of estrus (highest area under the curve = 0.87 in 3-month-old) but not of other phases was possible. Regardless of age, individual cycle phase (by smears) never correlated with corresponding fecal estrogens, and estrus could not be predicted. In conclusion, while the fecal estrogens oscillation and frequency of estrus phase were affected by age, the systemic hormone release persisted. In mice, vaginal cytology did not reflect changes of systemic (fecal) estrogens, whereas impedance accurately identified estrus. The flaws and advantages of the examined monitoring methods should be considered in the design of future shock studies.

Sepsis and sepsis-induced organ dysfunction remain lethal and common conditions among intensive care patients. Accumulating evidence suggests that the matricellular Cyr61/CCN1 (cysteine-rich, angiogenic-inducer, 61) protein is involved in the regulation of inflammatory responses and possesses organ-protective capabilities in diseases of an inflammatory etiology. However, its regulation in sepsis remains largely unexplored. The present study provides a comprehensive description of CCN1 regulation in the circulation and vital organs during experimentally induced sepsis with developing organ dysfunction. Female CD-1 mice served as baseline controls or were subjected to cecal ligation and puncture (CLP) for 18 to 96 h, and CCN1 regulation was analyzed in selected organs and in the circulation. A 5-, 5-, and 3-fold increases in circulating CCN1 protein were observed at 18, 48, and 96 h after CLP, respectively. Hepatic and pulmonary CCN1 mRNA expression was down-regulated by 80%, 60%, and 55% and 85%, 80%, and 65% at 18, 48, and 96 h after CLP and undetectable in circulating white blood cells. To identify a potential source for the circulating protein, mouse and human platelets were explored and revealed to contain CCN1. Human platelets were stimulated by thrombin and a specific PAR1 agonist (SFLLRN) in vitro. Both agonists induced an instant CCN1 release, and the effect of SFLLRN was blocked by the specific antagonist RWJ56110. The current study demonstrates that experimental sepsis is associated with a robust increase in circulating CCN1 protein levels and a paradoxical downregulation of CCN1 mRNA expression in vital organs. It provides evidence that CCN1 is released from activated platelets, suggesting that platelets constitute a novel source for CCN1 release to the circulation during sepsis.

Magnetic resonance imaging (MRI) provides the opportunity of tracking cells in vivo. Major challenges in dissecting cells from the recipient tissue and signal sensitivity constraints albeit exist. In this study, we aimed to tackle these limitations in order to study inflammation in autoimmune encephalomyelitis. We constructed a very small dual-tunable radio frequency (RF) birdcage probe tailored for (19)F (fluorine) and (1)H (proton) MR mouse neuroimaging. The novel design eliminated the need for extra electrical components on the probe structure and afforded a uniform -field as well as good SNR. We employed fluorescently-tagged (19)F nanoparticles and could study the dynamics of inflammatory cells between CNS and lymphatic system during development of encephalomyelitis, even within regions of the brain that are otherwise not easily visualized by conventional probes. (19)F/(1)H MR Neuroimaging will allow us to study the nature of immune cell infiltration during brain inflammation over an extensive period of time.

Age/gender may likely influence the course of septic complications after trauma. We aimed to characterize the influence of age/gender on the response of circulating cytokines, cells and organ function in post-traumatic sepsis. We additionally tested whether post-traumatic responses alone can accurately predict outcomes in subsequent post-traumatic sepsis. A mouse 2-hit model of trauma/hemorrhage (TH, 1(st) hit) and cecal ligation and puncture (CLP, 2(nd) hit) was employed. 3, 15 and 20 month (m) old female (♀) and male (♂) CD-1 mice underwent sublethal TH followed by CLP 2 days later. Blood was sampled daily until day 6 post-TH and survival was followed for 16 days. To compare general response patterns among groups, we calculated two scores: the inflammatory response (including KC, MIP-1α, TNFα, MCP-1, IFNγ, IL-1β,-5,-6,-10) and the organ dysfunction score (Urea, ALT, AST and LDH). Moreover, mice were retrospectively divided into survivors (SUR) and dying (DIE) based on post-CLP outcome. In general, females survived better than males and their survival did not correspond to any specific estrus cycle phase. Pre-CLP phase: the post-TH inflammatory score was weakest in 3 m♂ but there were no changes among remaining groups (similar lack of differences in the organ dysfunction score). TH induced a 40% increase of IFNγ, MIP-1α and IL-5 in 15 m♂ SUR (vs. DIE) but predictive accuracy for post-CLP outcomes was moderate. Post-CLP phase: while stable in males, inflammatory response score in 15 m and 20 m females decreased with age at day 1 and 2 post-CLP. SUR vs. DIE differences in inflammatory and organ dysfunction score were evident but their magnitude was comparable across age/gender. Nearly identical activation of the humoral inflammatory and organ function compartments, both across groups and according to sepsis severity, suggests that they are not directly responsible for the age/gender-dependent disparity in TH-CLP survival in the studied young-to-mature population.

To simulate and monitor the evolution of posttraumatic sepsis in mice, we combined a two-hit model of trauma/hemorrhage (TH) followed by polymicrobial sepsis with repetitive blood sampling. Anesthetized mice underwent femur fracture/sublethal hemorrhage and cecal ligation and puncture (CLP) 48 h later. To monitor outcome-dependent changes in circulating cells/biomarkers, mice were sampled daily (facial vein) for 7 days and retrospectively divided into either dead (DIE) or surviving (SUR) by post-CLP day 7. Prior to CLP, AST was 3-fold higher in DIE, while all other post-TH changes were similar between groups. There was a significant post-CLP intergroup separation. In SUR, RBC and Hb were lower, platelets and neutrophils higher, and lymphocytes mixed compared to DIE. In DIE, all organ function markers except glucose (decrease) were few folds higher compared to SUR. In summary, the combination of daily monitoring with an adequate two-hit model simulates the ICU setting, allows insight into outcome-based responses, and can identify biomarkers indicative of death in the acute posttraumatic sepsis in mice.

Self-assembly has proven to be a powerful tool for functional, smart materials such as hydrogels derived from low molecular weight compounds. However, the targeted design of functional gelators remains difficult. Here, we present a set of four Y-shaped aromatic amide tetramers with varying functionalities able to undergo different non- covalent interactions. These compounds were explored towards their self-assembly behavior and hydrogel formation by experimental methods such as UV-vis spectroscopy, rheology, small angle X-ray scattering (SAXS), scanning/transmission electron, and atomic force microscopy. Additionally, we investigated the main mechanisms behind oligomer aggregation and the structure of the resulting supramolecular chains through full atomistic molecular dynamics simulations.