Acute Tissue Damage Research Articles

Acute and Subacute Pulmonary Toxicity Caused by a Single Intratracheal Instillation of Colloidal Silver Nanoparticles in Mice: Pathobiological Changes and Metallothionein Responses

To study the acute and subacute pulmonary toxicity of colloidal silver nanoparticles (Ag-NPs), 0 or 100 ppm of Ag-NPs were instilled intratracheally in mice. Cellular and biochemical parameters in bronchoalveolar lavage fluid (BALF) and histological alterations were determined 1, 3, 7, 15, and 30 days after instillation. Ag-NPs induced moderate pulmonary inflammation and injury on BALF indices during the acute period; however, these changes gradually regressed in a time-dependent manner. Concomitant histopathological and laminin immunohistochemical findings generally correlated to BALF data. Superoxide dismutase and metallothionein expression occurred in particle-laden macrophages and alveolar epithelial cells, which correlated to lung lesions in mice treated with Ag-NPs. These findings suggest that instillation of Ag-NPs causes transient moderate acute lung inflammation and tissue damage. Oxidative stress may underlie the induction of injury to lung tissue. Moreover, the expression of metallothionein in tissues indicated the protective response to exposure to Ag-NPs.

MRI texture heterogeneity in the optic nerve predicts visual recovery after acute optic neuritis.

PurposeTo test the feasibility of using multi-scale MRI texture analysis to assess optic nerve pathology and to investigate how visual recovery relates to the severity of acute tissue damage in the optic nerve in patients after optic neuritis (ON).Materials and MethodsWe recruited 25 patients with acute ON. Retinal nerve fiber layer (RNFL) thickness; MRI lesion length and enhancement; optic nerve area ratio; and multi-scale MRI texture analysis, a measure of structural integrity, were used to assess tissue damage at baseline, and at 6 and 12 months. The recovery in vision was defined as the functional outcome. Eight healthy subjects were imaged for control.ResultsWe identified 25 lesions in the affected eyes (9 enhanced) and 5 in the clinically non-affected eyes (none enhanced). At baseline, we found that RNFL values were 20% thicker and lesion texture 14% more heterogeneous in the affected eyes than in the non-affected eyes, and lesion texture ratio of affected to non-affected eyes was greater in patients than in controls. In the affected eyes, visual acuity recovered significantly over 6 (18/23 patients) and 12 months (18/21 patients) when RNFL thickness and optic nerve area ratio decreased over time. Texture heterogeneity in the standard MRI of acute optic nerve lesions was the only measure that predicted functional recovery after ON.ConclusionsTissue heterogeneity may be a potential measure of functional outcome in ON patients and advanced analysis of the texture in standard MRI could provide insights into mechanisms of injury and recovery in patients with similar disorders.

Membrane Signaling Induced by High Doses of Ionizing Radiation in the Endothelial Compartment. Relevance in Radiation Toxicity

Tumor areas can now be very precisely delimited thanks to technical progress in imaging and ballistics. This has also led to the development of novel radiotherapy protocols, delivering higher doses of ionizing radiation directly to cancer cells. Despite this, radiation toxicity in healthy tissue remains a major issue, particularly with dose-escalation in these new protocols. Acute and late tissue damage following irradiation have both been linked to the endothelium irrigating normal tissues. The molecular mechanisms involved in the endothelial response to high doses of radiation are associated with signaling from the plasma membrane, mainly via the acid sphingomyelinase/ceramide pathway. This review describes this signaling pathway and discusses the relevance of targeting endothelial signaling to protect healthy tissues from the deleterious effects of high doses of radiation.

Novel biologically-inspired rosette nanotube PLLA scaffolds for improving human mesenchymal stem cell chondrogenic differentiation

Cartilage defects are a persistent issue in orthopedic tissue engineering where acute and chronic tissue damage stemming from osteoarthritis, trauma, and sport injuries, present a common and serious clinical problem. Unlike bone, cartilage repair continues to be largely intractable due to the tissue's inherently poor regenerative capacity. Thus, the objective of this study is to design a novel tissue engineered nanostructured cartilage scaffold via biologically-inspired self-assembling rosette nanotubes (RNTs) and biocompatible non-woven poly (l-lactic acid) (PLLA) for enhanced human bone marrow mesenchymal stem cell (hMSC) chondrogenic differentiation. Specifically, RNTs are a new class of biomimetic supramolecular nanomaterial obtained through the self-assembly of low-molecular-weight modified guanine/cytosine DNA base hybrids (the G∧C motif) in an aqueous environment. In this study, we synthesized a novel twin G∧C-based RNT (TB-RGDSK) functionalized with cell-favorable arginine–glycine–aspartic acid–serine–lysine (RGDSK) integrin binding peptide and a twin G∧C based RNT with an aminobutane linker molecule (TBL). hMSC adhesion, proliferation and chondrogenic differentiation were evaluated in vitro in scaffold groups consisting of biocompatible PLLA with TBL, 1:9 TB-RGDSK:TBL, and TB-RGDSK, respectively. Our results show that RNTs can remarkably increase total glycosaminoglycan, collagen, and protein production when compared to PLLA controls without nanotubes. Furthermore, the TB-RGDSK with 100% well-organized RGDSK peptides achieved the highest chondrogenic differentiation of hMSCs. The current in vitro study illustrated that RNT nanotopography and surface chemistry played an important role in enhancing hMSC chondrogenic differentiation thus making them promising for cartilage regeneration.

Hypoxia-Induced miR-210 Modulates Tissue Response to Acute Peripheral Ischemia

Peripheral artery disease is caused by the restriction or occlusion of arteries supplying the leg. Better understanding of the molecular mechanisms underpinning tissue response to ischemia is urgently needed to improve therapeutic options. The aim of this study is to investigate hypoxia-induced miR-210 regulation and its role in a mouse model of hindlimb ischemia. miR-210 expression was induced by femoral artery dissection. To study the role of miR-210, its function was inhibited by the systemic administration of a miR-210 complementary locked nucleic acid (LNA)-oligonucleotide (anti-miR-210). In the ischemic skeletal muscle, anti-miR-210 caused a marked decrease of miR-210 compared with LNA-scramble control, while miR-210 target expression increased accordingly. Histological evaluation of acute tissue damage showed that miR-210 inhibition increased both apoptosis at 1 day and necrosis at 3 days. Capillary density decrease caused by ischemia was significantly more pronounced in anti-miR-210-treated mice; residual limb perfusion decreased accordingly. To investigate the molecular mechanisms underpinning the increased damage triggered by miR-210 blockade, we tested the impact of anti-miR-210 treatment on the transcriptome. Gene expression analysis highlighted the deregulation of mitochondrial function and redox balance. Accordingly, oxidative damage was more severe in the ischemic limb of anti-miR-210-treated mice and miR-210 inhibition increased oxidative metabolism. Further, oxidative-stress resistant p66(Shc)-null mice displayed decreased tissue damage following ischemia. This study identifies miR-210 as a crucial element in the adaptive mechanisms to acute peripheral ischemia. The physiopathological significance of miR-210 is context dependent. In the ischemic skeletal muscle it seems to be cytoprotective, regulating oxidative metabolism and oxidative stress.

Serum Biomarkers as Predictors of Stage of Work-related Musculoskeletal Disorders

Musculoskeletal disorders (MSDs) are a leading worldwide cause of long-term pain and physical disability,1 with diagnoses including tendinopathies, nerve compression syndromes, and muscular and joint disorders.2,3 Studies in people with upper extremity work-related MSDs (WMSDs) find evidence of inflammation, fibrosis, and degeneration in serum and musculotendinous tissues, although the timing of each is unknown.4-7 Serum biomarkers that might aid in pinpointing the stage of these disorders are being investigated. Several risk factors have been identified, including forceful exertions, repetitive motion, and nonneutral body postures. A recent systematic review showed a consistent pattern of force-repetition interaction for musculoskeletal disorder risk, with low-force repetitive tasks demonstrating a modest increase in MSD risk, whereas high-force repetitive tasks result in rapid escalation in MSD risk, which is indicative of tissue fatigue failure.8 We have developed a rat model of voluntary reaching and handlepulling for food reward,9 in which reach rates and force levels were determined from epidemiologic studies. One goal of our laboratory is to identify biomarkers for monitoring disease progression of WMSDs and appropriate targeting of treatments. We recently examined whether serum inflammatory cytokines exhibit force × repetition interaction responses using this rat model.10 Serum tumor necrosis factor-α (TNF-α) shows a significant force × repetition interaction (P = 0.0003) with task performance (Figure 1, A). No increases in TNF-α were seen in low-force groups, but high increases were observed in rats performing high-repetition, high-force tasks.11-13 These results indicate that serum TNF-α follows the fatigue-failure theory during acute phases of ≤3 months. TNF-α and related cytokines may provide the best gauge of overall acute tissue damage resulting from repetitive, forceful exertions and may be the best biomarkers of this phase of WMSDs.Figure 1: Graph of serum biomarkers in a rat model of upper extremity work-related musculoskeletal disorders. A, Serum levels of tumor necrosis factor (TNF)-α in rats performing one of four tasks for 12 weeks. B, Schematic illustration showing temporal changes in serum levels of TNF-α and interleukin-10 (IL-10) (left axis) and connective tissue growth factor (CTGF) (right axis) in rats performing high-repetition, low-force (HRLF) tasks for 24 weeks. HRHF = high-repetition, high-force; LRHF = low-repetition, high-force; LRLF = low-repetition, low-forceThe timing of the inflammatory versus fibrotic responses with WMSDs is also of clinical interest. Studies have detected serum biomarkers of inflammation in patients with upper extremity WMSDs of short duration (≤3 months), including TNF-α,4-6 again suggesting a role for inflammatory cytokines early in the course of upper extremity WMSDs. However, studies examining tissues from patients with upper extremity WMSDs during surgical intervention show increased tissue fibrogenic proteins and fibrotic histopathology, which is indicative of deranged extracellular matrix production and degeneration in tissues by this time point.7 Therefore, we extended our rat studies to examine the effects of performing a high-repetition, low-force task for 24 weeks. Serum TNF-α levels increased early after training but declined by week 18 (Figure 1, B). In contrast, serum interleukin-10 (IL-10), an anti-inflammatory cytokine, increased steadily until week 18. This may be one reason for the decreasing TNF-α because IL-10 plays a key role in limiting immune responses. We next examined serum for connective tissue growth factor (CTGF), an important mediator of fibrosis. Studies have shown that CTGF increases in tissues under conditions of overload or injury and that it is a key player in the pathogenesis of fibrosis.14 We observed increased serum and tissue CTGF by week 24, compared with controls (P = 0.03) (Figure 1, B). It is known that transforming growth factor-β1 induces CTGF expression, leading to fibroblast proliferation and collagen deposition.14 However, CTGF production is also regulated by TNF-α,15 which is an interesting fact considering their temporal relationship (Figure 1, B). Importantly, because the CTGF level is normally low in sera of healthy individuals, it may serve as a predictive biomarker for patients in the fibrotic stage of WMSDs. Our results indicate that most serum inflammatory cytokines, including TNF-α, demonstrate force-repetition interactions. These findings support the use of key pro-inflammatory cytokines as biomarkers of acute tissue damage and the fatigue failure hypothesis as a mechanism underlying WMSDs. We have also observed significantly increased serum and tissue CTGF levels that correlated with tissue fibrosis. Additional studies are underway to determine whether elevated CTGF is an essential mediator of fibrotic events. If so, one could envision CTGF as a potential therapeutic target to prevent fibrosis and reduced function and as a serum biomarker of tissue fibrogenic changes occurring with WMSDs.

Alphacoronavirus Protein 7 Modulates Host Innate Immune Response

Innate immune response is the first line of antiviral defense resulting, in most cases, in pathogen clearance with minimal clinical consequences. Viruses have developed diverse strategies to subvert host defense mechanisms and increase their survival. In the transmissible gastroenteritis virus (TGEV) as a model, we previously reported that accessory gene 7 counteracts the host antiviral response by associating with the catalytic subunit of protein phosphatase 1 (PP1c). In the present work, the effect of the absence of gene 7 on the host cell, during infection, was further analyzed by transcriptomic analysis. The pattern of gene expression of cells infected with a recombinant mutant TGEV, lacking gene 7 expression (rTGEV-Δ7), was compared to that of cells infected with the parental virus (rTGEV-wt). Genes involved in the immune response, the interferon response, and inflammation were upregulated during TGEV infection in the absence of gene 7. An exacerbated innate immune response during infection with rTGEV-Δ7 virus was observed both in vitro and in vivo. An increase in macrophage recruitment and activation in lung tissues infected with rTGEV-Δ7 virus was observed compared to cells infected with the parental virus. In summary, the absence of protein 7 both in vitro and in vivo led to increased proinflammatory responses and acute tissue damage after infection. In a porcine animal model, which is immunologically similar to humans, we present a novel example of how viral proteins counteract host antiviral pathways to determine the infection outcome and pathogenesis.

Morphological and Molecular Characterization of Adult Midgut Compartmentalization in Drosophila

Although the gut is a central organ of Eumetazoans and is essential for organismal health, our understanding of its morphological and molecular determinants remains rudimentary. Here, we provide a comprehensive atlas of Drosophila adult midgut. Specifically, we uncover a fine-grained regional organization consisting of 14 subregions with distinct morphological, histological, and genetic properties. We also show that Drosophila intestinal regionalization is defined after adult emergence, remains stable throughout life, and reestablishes following acute tissue damage. Additionally, we show that this midgut compartmentalization is achieved through the interplay between pan-midgut and regionalized transcription factors, in concert with spatial activities of morphogens. Interestingly, disruption of the midgut compartmentalization leads to a loss of intestinal homeostasis characterized by an increase in stem cell proliferation and aberrant immune responses. Our integrative analysis of Drosophila midgut compartmentalization provides insights into the conserved mechanisms underlying intestinal regionalization in metazoans.

Abstract 3632: The relationships between c-reactive protein, smoking, and lung cancer mortality in the Third National Health and Nutrition Examination Survey.

Abstract Background: Chronic inflammation plays an important role in carcinogenesis for several cancers. C-reactive protein (CRP) is an acute-phase protein that displays a rapid and distinct rise in its plasma concentration in response to acute inflammation, infection and tissue damage. CRP levels have been found to be moderately elevated in individuals with chronic inflammatory diseases, including lung cancer. Few studies have examined associations between lung cancer, CRP, smoking, and other inflammatory factors. The purpose of this study was to examine serum CRP, smoking, obesity, and serum vitamin D levels in relation to lung cancer mortality. It was hypothesized that increased serum CRP levels, smoking, obesity and decreased serum vitamin D levels would result in increased lung cancer mortality. Methods: Data from cancer-free individuals over age 40 in the Third National Health and Nutrition Examination Survey (NHANESIII:1988-1994) were examined prospectively in relation to inflammatory factors and lung cancer mortality. Mortality status was ascertained through probabilistic record matching using the National Death Index, with mortality follow-up through 2006. Baseline demographic and clinical data were acquired from interviews and laboratory examinations. Cox proportional hazards regression models were used to assess factors related to inflammation and lung cancer mortality. Results: Of 10,735 participants, 219 individuals died of lung cancer during follow-up. Individuals who died from lung cancer were significantly more likely to be male (67% vs 47%), non-white (34% vs 27%), older (65 vs 62 years), to have elevated serum CRP levels (>3mg/L; 41% vs 33%), lower mean BMI (26 vs 28 kg/m2), and to have ever smoked >100 cigarettes (94% vs 54%) than lung cancer survivors. Mean serum vitamin D levels were similar for both groups (25.4 ng/ml). Multivariate regression analysis revealed greater lung cancer mortality risk for elevated CRP levels when adjusting for age, gender, BMI and ever having smoked (HR=1.80; p<0.001). The lung cancer mortality risk for smokers increased 10-fold when adjusting for other factors (p<0.0001). Also, lung cancer mortality risk increased with older age and male gender (HR=1.05 and 1.45;p<0.01, respectively), but higher BMI levels showed a slightly protective effect (HR=0.92;p<0.0001). Conclusions: The multivariate models in this study showed associations between elevated CRP and lung cancer mortality risk even when adjusting for other factors related to inflammation, such as obesity and smoking. The lung cancer mortality risk for smokers increased 10-fold when adjusting for other factors, whereas higher obesity levels showed a protective effect. Future studies should further explore CRP as a biomarker of lung cancer risk and mechanisms that mediate the CRP-lung cancer relationship, such as obesity, diet and smoking. Citation Format: Marisa A. Bittoni, Randall E. Harris, Steven K. Clinton, Brian C. Focht. The relationships between c-reactive protein, smoking, and lung cancer mortality in the Third National Health and Nutrition Examination Survey. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3632. doi:10.1158/1538-7445.AM2013-3632

Cortical activity evoked by an acute painful tissue-damaging stimulus in healthy adult volunteers.

Everyday painful experiences are usually single events accompanied by tissue damage, and yet most experimental studies of cutaneous nociceptive processing in the brain use repeated laser, thermal, or electrical stimulations that do not damage the skin. In this study the nociceptive activity in the brain evoked by tissue-damaging skin lance was analyzed with electroencephalography (EEG) in 20 healthy adult volunteers (13 men and 7 women) aged 21–40 yr. Time-frequency analysis of the evoked activity revealed a distinct late event-related vertex potential (lance event-related potential, LERP) at 100–300 ms consisting of a phase-locked energy increase between 1 and 20 Hz (delta-beta bands). A pairwise comparison between lance and sham control stimulation also revealed a period of ultralate stronger desynchronization after lance in the delta band (1–5 Hz). Skin application of mustard oil before lancing, which sensitizes a subpopulation of nociceptors expressing the cation channel TRPA1, did not affect the ultralate desynchronization but reduced the phase-locked energy increase in delta and beta bands, suggesting a central interaction between different modalities of nociceptive inputs. Verbal descriptor screening of individual pain experience revealed that lance pain is predominantly due to Aδ fiber activation, but when individuals describe lances as C fiber mediated, an ultralate delta band event-related desynchronization occurs in the brain-evoked activity. We conclude that pain evoked by acute tissue damage is associated with distinct Aδ and C fiber-mediated patterns of synchronization and desynchronization of EEG oscillations in the brain.

Inhibiting TGFβ1 has a protective effect on mouse bone marrow suppression following ionizing radiation exposure in vitro

Ionizing radiation (IR) causes not only acute tissue damage but also residual bone marrow (BM) suppression. The induction of residual BM injury is primarily attributable to the induction of reactive oxygen species (ROS) pressure in hematopoietic cells. In this study, we examined if SB431542, a transforming growth factor β1 (TGFβ1) inhibitor, can mitigate IR-induced BM suppression in vitro. Our results showed that treatment with SB431542 protected mice bone marrow mononuclear cells (BMMNCs), hematopoietic progenitor cells (HPCs) and hematopoietic stem cells (HSCs) from IR-induced suppression using cell viability assays, clonogenic assays and competitive repopulation assays. Moreover, expression of gene-related ROS production in hematopoietic cells was analyzed. The expression of NOX1, NOX2 and NOX4 was increased in irradiated BMMNCs, and that of NOX2 and NOX4 was reduced by SB431542 treatment. Therefore, the results from this study suggest that SB431542, a TGFβ1 inhibitor, alleviates IR-induced BM suppression at least in part via inhibiting IR-induced NOX2 and NOX4 expression.

Between Scylla and Charybdis: The role of the human immune system in the pathogenesis of hepatitis C

Hepatitis C virus (HCV) frequently elicits only mild immune responses so that it can often establish chronic infection. In this case HCV antigens persist and continue to stimulate the immune system. Antigen persistence then leads to profound changes in the infected host's immune responsiveness, and eventually contributes to the pathology of chronic hepatitis. This topic highlight summarizes changes associated with chronic hepatitis C concerning innate immunity (interferons, natural killer cells), adaptive immune responses (immunoglobulins, T cells, and mechanisms of immune regulation (regulatory T cells). Our overview clarifies that a strong anti-HCV immune response is frequently associated with acute severe tissue damage. In chronic hepatitis C, however, the effector arms of the immune system either become refractory to activation or take over regulatory functions. Taken together these changes in immunity may lead to persistent liver damage and cirrhosis. Consequently, effector arms of the immune system will not only be considered with respect to antiviral defence but also as pivotal mechanisms of inflammation, necrosis and progression to cirrhosis. Thus, avoiding Scylla - a strong, sustained antiviral immune response with inital tissue damage - takes the infected host to virus-triggered immunopathology, which ultimately leads to cirrhosis and liver cancer - the realm of Charybdis.

A multi-center study on the regenerative effects of erythropoietin in burn and scalding injuries: study protocol for a randomized controlled trial

Although it was initially assumed that erythropoietin (EPO) was a hormone that only affected erythropoiesis, it has now been proposed that EPO plays an additional key role in the regulation of acute and chronic tissue damage. Via the inhibition of inflammatory reactions and of apoptosis, stem cell recruitment, advancement of angiogenesis and growth factor release, EPO enhances healing and thus restitutio ad integrum after trauma. Human skin contains EPO receptors and is able to synthesize EPO. We therefore hypothesize that EPO is able to optimize wound healing in thermally injured patients. This is a large, prospective, randomized, double-blind, multi-center study, funded by the German Federal Ministry of Education and Research, and fully approved by the designated ethics committee. The trial, which is to investigate the effects of EPO in severely burned patients, is in its recruitment phase and is being carried out in 13 German burn care centers. A total of 150 patients are to be enrolled to receive study medication every other day for 21 days (EPO 150 IU/kg body weight or placebo). A follow-up of one year is planned. The primary endpoint of this study is the time until complete re-epithelialization of a defined skin graft donor site is reached. Furthermore, clinical parameters such as wound healing, scar formation (using the Vancouver scar scale), laboratory values, quality of life (SF-36), angiogenic effects, and gene- and protein-expression patterns are to be determined. The results will be carefully evaluated for gender differences. We are seeking new insights into the mechanisms of wound healing in thermally injured patients and more detailed information about the role EPO plays, specifically in these complex interactions. We additionally expect that the biomimetic effects of EPO will be useful in the treatment of acute thermal dermal injuries. EudraCT Number: 2006-002886-38, Protocol Number: 0506, ISRCT Number: http://controlled-trials.com/ISRCTN95777824/ISRCTN95777824 .

O6-methylguanine DNA Damage Signals Through Nfkb1/p50 to Potentiate DNA Strand Break-induced Cytotoxicity

and 6 hr of NFK-b, Nrf2 and TGF-b. MnSOD tet/tet cells, maintained in DOX, did show at 6 hr after irradiation a 50% increase in expression of Nrf2. Conclusions: MnSOD tet/tet cell lines are radiosensitive, as reflected in decreased irradiation induced gene expression which is only partially reversed by DOX. These novel mice and derived cell lines should prove valuable for understanding the link between antioxidant levels and irradiation responsive genes mediating both acute and chronic normal tissue damage effects. Acknowledgements: This project was supported by NIAID U191A168021. Author Disclosure: R. Kalash: None. J.R. Chaillet: None. F. Houghton: None. X. Zhang: None. M. Epperly: None. S. Cao: None. J.S. Greenberger: None.

Mast Cells and Ionizing Radiation Induce a Synergistic Expression of Inflammatory Genes in Endothelial Cells by a Mechanism Involving p38α MAP Kinase and (p65) NF-κB Activation

Vascular endothelium is a key compartment involved in the development of normal tissue toxicity associated with cancer radiation therapy, i.e., acute inflammation and late fibrosis. Radiation-induced endothelial cell activation has been extensively studied, and activated endothelial cells are characterized by increased expression of inflammatory mediators and adhesion molecules, and activation of the coagulation and thrombosis pathways. However, little is known about the role of vascular endothelium interaction with resident immune cells, such as mast cells on its response to irradiation. Here, we report that endothelial exposure to mast cell conditioned medium and irradiation induces a synergistic expression of many inflammatory genes including interleukin-6 and interleukin-8, CXCL2 and E-selectin. This synergy is blocked by the histamine H1 receptor antagonist mepyramine and partially mimicked by exogenous histamine addition before irradiation. Using pharmacological and molecular inhibition approaches, we show the p38α MAP kinase and p65 (NF-κB) dependence of the synergy. Moreover, our data show a link between both pathways, with p65 (NF-κB) being downstream of p38. These data highlight the possible exacerbation of the radiation-induced endothelial inflammatory response by its interactions with immune cells. It also suggest that p38α MAP kinase and p65 (NF-κB) inhibition in vascular endothelium may limit excessive tissue inflammation induced by radiation therapy, and thereby limit the associated acute and late tissue damage.

In vivo two-photon microscopy reveals immediate microglial reaction to implantation of microelectrode through extension of processes

Objective. Penetrating cortical neural probe technologies allow investigators to record electrical signals in the brain. Implantation of probes results in acute tissue damage, and microglia density increases around implanted devices over weeks. However, the mechanisms underlying this encapsulation are not well understood in the acute temporal domain. The objective here was to evaluate dynamic microglial response to implanted probes using two-photon microscopy. Approach. Using two-photon in vivo microscopy, cortical microglia ∼200 µm below the surface of the visual cortex were imaged every minute in mice with green fluorescent protein-expressing microglia. Main results. Following probe insertion, nearby microglia immediately extended processes toward the probe at (1.6 ± 1.3) µm min−1 during the first 30–45 min, but showed negligible cell body movement for the first 6 h. Six hours following probe insertion, microglia at distances <130.0 µm (p = 0.5) from the probe surface exhibit morphological characteristics of transitional stage (T-stage) activation, similar to the microglial response observed with laser-induced blood–brain barrier damage. T-stage morphology and microglia directionality indexes were developed to characterize microglial response to implanted probes. Evidence suggesting vascular reorganization after probe insertion and distant vessel damage was also observed hours after probe insertion. Significance. A precise temporal understanding of the cellular response to microelectrode implantation will facilitate the search for molecular cues initiating and attenuating the reactive tissue response.

Cryocompression Therapy after Elective Arthroplasty of the Hip

Pneumatic compression and cryotherapy have been successfully being employed in the management of acute tissue damage. The Game Ready System (GRS) combines cyclic compression and cryotherapy. No randomised controlled trial has been performed on the effects of combined cyclic compression and cryotherapy in total hip arthroplasty (THA). We observed postoperative pain, morphine usage, blood loss, wound discharge, patient and medical staff satisfaction, together with the feasibility of a cryocompression machine, total hospital admission time, infection rate, deep vein thrombosis, and short-term prosthesis related problems in this context. Thirty patients, mean age 68 yrs (range 31-83 yrs) undergoing elective hip arthroplasty for end-stage osteoarthritis were included. Control patients (n = 15) received a tricot compression bandage alone, and patients studied received a tricot compression bandage plus intermittent cryocompression therapy 15 times for 30 minutes. Haemoglobin levels on postoperative day (POD) 1 dropped 2.34 mmol/L in the control group and 1,87 mmol/L in the intervention group (p = 0,027). At POD 3 haemoglobin levels were reduced by 2,63 and 2,16 respectively (p = 0,646). A trend occurred towards lower morphine usage, shorter hospital admission time and less wound discharge in the study group. No difference was found in postoperative pain scores. One event of deep venous thrombosis occurred in the control group. Intermittent cryocompression therefore appears to reduce postoperative blood loss. A trend towards less analgesic use, shorter hospital stay, less wound discharge and less pain at 6 weeks postoperatively was also observed.

Interleukin-22 Protects Intestinal Stem Cells from Immune-Mediated Tissue Damage and Regulates Sensitivity to Graft versus Host Disease

Little is known about the maintenance of intestinal stem cells (ISCs) and progenitors during immune-mediated tissue damage or about the susceptibility of transplant recipients to tissue damage mediated by the donor immune system during graft versus host disease (GVHD). We demonstrate here that deficiency of recipient-derived IL-22 increased acute GVHD tissue damage and mortality, that ISCs were eliminated during GVHD, and that ISCs as well as their downstream progenitors expressed the IL-22 receptor. Intestinal IL-22 was produced after bone marrow transplant by IL-23-responsive innate lymphoid cells (ILCs) from the transplant recipients, and intestinal IL-22 increased in response to pretransplant conditioning. However, ILC frequency and IL-22 amounts were decreased by GVHD. Recipient IL-22 deficiency led to increased crypt apoptosis, depletion of ISCs, and loss of epithelial integrity. Our findings reveal IL-22 as a critical regulator of tissue sensitivity to GVHD and a protective factor for ISCs during inflammatory intestinal damage.

Early verification of myocardial ischemia with a novel biomarker of acute tissue damage: C-reactive protein fractional forms

BackgroundWe evaluated the utility of an independent biomarker of early ischemic cellular damage—circulating fractional forms of C-reactive protein (fracCRP), to verify the diagnostic relevance of low Troponin I (TnI) values within the context of a workup for Acute Coronary Syndrome (ACS). MethodsOn a semi-preparative scale, the molecular characteristics of fracCRP were established by electron microscopy and Western Blot, using isolates captured from patient serum on phosphorylcholine beads and purified by size exclusion high-pressure liquid chromatography (SE-HPLC). Captured on an analytical scale, the diagnostic utility of fracCRP was evaluated in first-draw plasma specimens (total CRP not exceeding 6mg/l) recovered from 300 cardiac emergency patients with final discharge diagnoses of ACS ruled out (N=132) or ruled in (N=168). ResultsAt a cutoff value chosen for 97.7% test specificity, the test metric (fracCRP×TnI) identified in the first blood draw 39.9% of all emergency patients ultimately diagnosed with ACS, and 17.9% of ultimately diagnosed patients who arrived with TnI values within the normal reference range (0.01–0.04ng/ml). ConclusionsThese findings suggest that the fracCRP test metric could serve as a rule-in test for ACS in a significant proportion of low to moderate risk emergency patients.

Abstract 3520: Major Neurological Improvement is Predicted by Recanalisation and Absence of Acute Tissue Damage: An Analysis of 2'006 Consecutive Acute Ischemic Strokes

Introduction: Major neurological improvement (MNI) in acute ischemic stroke (AIS) is related to better outcome. We aimed to evaluate predictors of MNI in a large cohort of consecutive AIS patients. Methods: In the Acute STroke Registry and Analysis of Lausanne (ASTRAL), MNI was defined as ≥ 8 point improvement of NIHSS or a NIHSS of 0-1 after 24 hours. Patients with initial NIHSS of 0-1 were excluded and missing data were imputed. For comparison of patients with and without MNI, logistic regression analysis of a large number of demographical, clinical, radiological and metabolic data was performed. The influence of MNI on length of hospital stay (LOS), favorable outcome defined as modified Rankin score 0-2 at three and 12 months, and recurrence was also assessed in univariate analysis. Results: 203 patients were excluded because of initial NIHSS of 0-1. Before imputing 50 missing NIHSS values to obtain a sample of 2’006 patients, MNI occurred in 333 (17.0%). MNI was predicted by spontaneous or therapeutic intracranial recanalization (OR= 0.49, CI 0.31-0.76, p&lt;0.01) especially in the presence of eye deviation, absence of early ischemic lesions on neuroimaging (OR= 0.62, CI 0.47-0.82, p&lt;0.01), earlier onset to arrival delay (OR= 0.95/60 minutes, CI 0.93 - 0.97, p&lt;0.01) and lower systolic blood pressure at 24h (OR=0.92/10 mmHg, CI 0.86 - 0.98, p=0.01). Patients with MNI had significantly shorter LOS (median 8 vs. 10 days, p&lt;0.01), more frequent favorable three months (73.6% vs. 47.6%, p&lt;0.01) and 12 months outcome (66.1 vs. 43.5, p &lt; 0.01). They also had less three (3.9% vs. 17.3%, p&lt;0.01) and 12 months fatality (6.0% vs. 21.8% p &lt; 0.01). Recurrence rates at three months were similar (9.0% vs. 9.2%, p=0.86). Conclusion: Absence of radiological signs of irreversible tissue damage and arterial recanalisation are strong predictors of MNI. Earlier arrival to hospital delay and lower subacute SBP also contributed to MNI. We confirm that radiological markers are strong predictors of MNI in thrombolysed and untreated patients.