Transcriptomic clustering of critically ill COVID-19 patients.

BACKGROUND: Infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may cause a severe disease, termed coronavirus disease 2019 (COVID-19), with significant mortality. Host responses to this infection, mainly in terms of systemic inflammation, have emerged as key pathogenetic mechanisms and their modulation has shown a mortality benefit. METHODS: In a cohort of 56 critically ill COVID-19 patients, peripheral blood transcriptomes were obtained at admission to an intensive care unit (ICU) and clustered using an unsupervised algorithm. Differences in gene expression, circulating microRNAs (c-miRNAs) and clinical data between clusters were assessed, and circulating cell populations estimated from sequencing data. A transcriptomic signature was defined and applied to an external cohort to validate the findings. RESULTS: We identified two transcriptomic clusters characterised by expression of either interferon-related or immune checkpoint genes, respectively. Steroids have cluster-specific effects, decreasing lymphocyte activation in the former but promoting B-cell activation in the latter. These profiles have different ICU outcomes, despite no major clinical differences at ICU admission. A transcriptomic signature was used to identify these clusters in two external validation cohorts (with 50 and 60 patients), yielding similar results. CONCLUSIONS: These results reveal different underlying pathogenetic mechanisms and illustrate the potential of transcriptomics to identify patient endotypes in severe COVID-19 with the aim to ultimately personalise their therapies.

Epidemiology of Rink Hockey-Related Injuries.

CONTEXT: Determining the rate of injuries related to a certain sport is accepted as the primary step toward designing, implementing, and evaluating injury prevention programs. The aim of this study was to examine the injuries sustained by semiprofessional Spanish rink hockey players and to compare data per playing position. DESIGN: Observational and retrospective. METHODS: Athletes from 21 teams were surveyed via a self-reported questionnaire to screen for incidence, injury burden, location, tissue, and onset of injuries. RESULTS: Overall, 101 time loss injuries were reported across 22,241 hours of exposure, giving rise to an incidence rate of 4.5/1000 hours. The main body regions injured were the hip/groin, shoulder, thigh, and head, accounting altogether for 47.5% of all injuries. Musculotendinous injuries were the most frequent, comprising 27.7% of all injuries. Incidence accounted for 3.1/1000 hours during training and 23/1000 hours during games (P < .001). A high number of injuries were caused by contact (46.5%). No differences were found for any of the variables analyzed between outfield players and goalkeepers. CONCLUSION: The injury incidence in rink hockey is moderate, occurring mainly due to a contact mechanism. Preventative measurements should be implemented in rink hockey with a special concern for injuries affecting the hip/groin and head.

Mechanical ventilation promotes lung tumour spread by modulation of cholesterol cell content.

BACKGROUND: Mechanical stretch of cancer cells can alter their invasiveness. During mechanical ventilation, lungs may be exposed to an increased amount of stretch, but the consequences on lung tumours have not been explored. METHODS: To characterise the influence of mechanical ventilation on the behaviour of lung tumours, invasiveness assays and transcriptomic analyses were performed in cancer cell lines cultured in static conditions or under cyclic stretch. Mice harbouring lung melanoma implants were submitted to mechanical ventilation and metastatic spread was assessed. Additional in vivo experiments were performed to determine the mechanodependent specificity of the response. Incidence of metastases was studied in a cohort of lung cancer patients that received mechanical ventilation compared with a matched group of nonventilated patients. RESULTS: Stretch increases invasiveness in melanoma B16F10luc2 and lung adenocarcinoma A549 cells. We identified a mechanosensitive upregulation of pathways involved in cholesterol processing in vitro, leading to an increase in pro-protein convertase subtilisin/kexin type 9 (PCSK9) and LDLR expression, a decrease in intracellular cholesterol and preservation of cell stiffness. A course of mechanical ventilation in mice harbouring melanoma implants increased brain and kidney metastases 2 weeks later. Blockade of PCSK9 using a monoclonal antibody increased cell cholesterol and stiffness and decreased cell invasiveness in vitro and metastasis in vivo. In patients, mechanical ventilation increased PCSK9 abundance in lung tumours and the incidence of metastasis, thus decreasing survival. CONCLUSIONS: Our results suggest that mechanical stretch promote invasiveness of cancer cells, which may have clinically relevant consequences. Pharmacological manipulation of cholesterol endocytosis could be a novel therapeutic target in this setting.

Role of nutrition in the development and prevention of age-related hearing loss: A scoping review.

Age-related hearing loss (ARHL) is a major and increasingly prevalent health problem worldwide, causing disability and social isolation in the people who present it. This impairment is caused by genetic and environmental factors. Nutritional status has been identified as a related risk associated with hearing loss (HL). This scoping review aimed to characterize the links between HL and nutritional status. PubMed, Embase, Cochrane and Scopus databases were searched up to December 2019. Studies examining the relation between nutrition and dietary habits and HL were included. After screening 3510 citations, 22 publications were selected for inclusion in the current review, all of which were published between 2010 and 2019. Diets rich in saturated fats and cholesterol have deleterious effects on hearing that could be prevented by lower consumption. Conversely, greater consumption of fruit and vegetables, and of polyunsaturated fatty acids (omega-3) and anti-oxidants in the form of vitamins A, C, and E, prevent the development of ARHL. The current literature suggests a possible association between nutritional status and hearing loss. More studies are needed to better characterize the clinical consequences of this association.

Melatonin modulates mitophagy, innate immunity and circadian clocks in a model of viral-induced fulminant hepatic failure.

The haemorrhagic disease virus (RHDV) is a non-cultivable virus that promotes in rabbits an acute disease which accomplishes many characteristics of an animal model of fulminant hepatic failure (FHF). Beneficial effects of melatonin have been reported in RHDV-infected rabbits. This study investigated whether protection against viral-derived liver injury by melatonin is associated with modulation of mitophagy, innate immunity and clock signalling. Rabbits were experimentally infected with 2 × 104 haemagglutination units of a RHDV isolate and killed at 18, 24 and 30 hours after infection (hpi). Melatonin (20 mg/kg body weight ip) was administered at 0, 12 and 24 hpi. RHDV infection induced mitophagy, with the presence of a high number of mitophagosomes in hepatocytes and increased expression of mitophagy genes. Greater expression of main innate immune intermediaries and inflammasome components was also found in livers with RHDV-induced FHF. Both mitophagy and innate immunity activation was significantly hindered by melatonin. FHF induction also elicited an early dysregulation in clock signalling, and melatonin was able to prevent such circadian disruption. Our study discloses novel molecular routes contributing to RHDV-induced damage progression and supports the potential of melatonin as a promising therapeutic option in human FHF.

Should respiratory muscle training be part of the treatment of Parkinson's disease? A systematic review of randomized controlled trials.

OBJECTIVE: To determine the effectiveness of respiratory muscle training in persons with Parkinson's disease. DATA SOURCES: PubMed/MEDLINE, EMBASE, Web of Science, Scopus and PEDro electronic databases were searched until 15 November 2019. Reference lists of included studies were hand-searched. METHODS: Randomized controlled trials assessing the effects of respiratory muscle training programmes (both inspiratory and expiratory) in patients with Parkinson's disease were included. Two reviewers independently identified eligible studies and extracted data. Method quality was appraised with the PEDro scale. RESULTS: Five papers including three randomized controlled trials with a total of 111 patients were identified. Method appraisal showed a mean score of 5 in the PEDro scale. One study analysed inspiratory muscle training, one expiratory muscle training and two established a comparison between both of them. Statistically positive results were found in maximal inspiratory pressure (P < 0.05 and d = 0.76), maximal expiratory pressure (P < 0.01 and d = 1.40), perception of dyspnoea (P < 0.01), swallowing function (d = 0.55) and phonatory measures, without significant differences in spirometric indices. CONCLUSIONS: Respiratory muscle training may be an effective alternative for improving respiratory muscle strength, swallowing function and phonatory parameters in subjects with Parkinson's disease. Nevertheless, the lack of primary studies about this type of training prevents obtaining robust evidence.

Neuronal Cell Fate Specification by the Convergence of Different Spatiotemporal Cues on a Common Terminal Selector Cascade.

Specification of the myriad of unique neuronal subtypes found in the nervous system depends upon spatiotemporal cues and terminal selector gene cascades, often acting in sequential combinatorial codes to determine final cell fate. However, a specific neuronal cell subtype can often be generated in different parts of the nervous system and at different stages, indicating that different spatiotemporal cues can converge on the same terminal selectors to thereby generate a similar cell fate. However, the regulatory mechanisms underlying such convergence are poorly understood. The Nplp1 neuropeptide neurons in the Drosophila ventral nerve cord can be subdivided into the thoracic-ventral Tv1 neurons and the dorsal-medial dAp neurons. The activation of Nplp1 in Tv1 and dAp neurons depends upon the same terminal selector cascade: col>ap/eya>dimm>Nplp1. However, Tv1 and dAp neurons are generated by different neural progenitors (neuroblasts) with different spatiotemporal appearance. Here, we find that the same terminal selector cascade is triggered by Kr/pdm>grn in dAp neurons, but by Antp/hth/exd/lbe/cas in Tv1 neurons. Hence, two different spatiotemporal combinations can funnel into a common downstream terminal selector cascade to determine a highly related cell fate.

Melatonin modulates dysregulated circadian clocks in mice with diethylnitrosamine-induced hepatocellular carcinoma.

Disruption of circadian rhythms, which are regulated by the circadian clock machinery, plays an important role in different long-term diseases including hepatocellular carcinoma (HCC). Melatonin has been reported to alleviate promotion and progression of HCC, but the potential contribution of circadian clock modulation is unknown. We investigated the effects of melatonin in mice which received diethylnitrosamine (DEN) (35 mg/kg body weight ip) once a week for 8 weeks. Melatonin was given at 5 or 10 mg kg-1 d-1 ip beginning 4 weeks after the onset of DEN administration and ending at the sacrifice time (10, 20, 30, or 40 weeks). Liver expression of Bmal1, Clock, Npas2, Rorα, and Sirt1 increased, whereas Cry1, Per1, Per2, Per3, CK1ε, Rev-erbα, and Rev-erbß decreased following DEN administration. Melatonin treatment prevented changes in the expression of clock genes, and this effect was accompanied by an upregulation of the MT1 receptor and reduced levels of the hypoxia-inducible factors Hif-1α and Hif-2α. An increased expression of p21, p53, and PARP1/2, a higher Bax/Bcl-2 ratio, and a lower expression of Cyclin D1, CDK6, HSP70, HSP90, and GRP78 proteins were also observed in melatonin-treated mice. Melatonin significantly potentiated the suppression of proliferation and cell cycle arrest induced by the synthetic REV-ERB agonist SR9009 in human Hep3B cells, and BMAL1 knocking down attenuated the pro-apoptotic and antiproliferative effect of melatonin. Results support a contribution of changes in the circadian clock components to the beneficial effects of melatonin in HCC and highlight the usefulness of strategies modulating the circadian machinery in hepatocarcinogenesis.

Melatonin prevents deregulation of the sphingosine kinase/sphingosine 1-phosphate signaling pathway in a mouse model of diethylnitrosamine-induced hepatocellular carcinoma.

The sphingosine kinase (SphK)/sphingosine 1-phosphate (S1P) pathway is involved in multiple biological processes, including carcinogenesis. Melatonin shows beneficial effects in cell and animal models of hepatocellular carcinoma, but it is unknown if they are associated with the modulation of the SphK/S1P system, along with different downstream signaling pathways modified in cancer. We investigated the effects of melatonin in mice which received diethylnitrosamine (DEN) (35 mg/kg body weight i.p) once a week for 8 weeks. Melatonin was given at 5 or 10 mg/kg/day i.p. beginning 4 weeks after the onset of DEN administration and ending at the sacrifice time (10, 20, 30, or 40 weeks). Melatonin alleviated the distortion of normal hepatic architecture, lowered the incidence of preneoplastic/neoplastic lesions, and inhibited the expression of proliferative/cell cycle regulatory proteins (Ki67, PCNA, cyclin D1, cyclin E, CDK4, and CDK6). S1P levels and expression of SphK1, SphK2, and S1P receptors (S1PR1/S1PR3) were significantly elevated in DEN-treated mice. However, there was a decreased expression of S1P lyase. These effects were significantly abrogated in a time- and dose-dependent manner by melatonin, which also increased S1PR2 expression. Following DEN treatment, mice exhibited increased phosphorylation of PI3K, AKT, mTOR, STAT3, ERK, and p38, and a higher expression of NF-κB p50 and p65 subunits. Melatonin administration significantly inhibited those changes. Data obtained suggest a contribution of the SphK/S1P system and related signaling pathways to the protective effects of melatonin in hepatocarcinogenesis.

Effects Of Oral Glutamine on Inflammatory and Autophagy Responses in Cancer Patients Treated With Abdominal Radiotherapy: A Pilot Randomized Trial.

Background and Aims: Abdominal radiotherapy (RT) causes harm to the mid gastrointestinal mucosa by release of pro-inflammatory cytokines and promotes autophagic changes in tumor cells. This study was aimed to measure the effect of glutamine administration on markers of inflammation and autophagy in cancer patients treated with RT. Methods: In this double-blind, randomized, controlled pilot trial 43 patients under abdominal RT diagnosed of pelvic or abdominal malignancies receiving glutamine (30 g/d) or placebo (casein, 30 g/d). Patient recruitment took place in the Complejo Asistencial Universitario of León (CAULE), Spain. Patient evaluation took place at three different time points during the study: before RT (pre-treatment), in the middle of the RT period (mid-treatment), and after finishing RT (post-treatment). Data were compared by analysis of variance and the Newmann Keuls test. Significance was accepted at p < 0.05. Results Abdominal RT increased whole blood mRNA levels of inflammatory and autophagic markers, but glutamine administration showed significantly lower expression of toll-like receptor 4 (TLR4), CD36, interleukin-1ß (IL-1ß), tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2), and matrix metalloproteinase-9 (MMP-9). Moreover, glutamine reduced the expression of the transcription factors nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1). Glutamine also inhibited the autophagic response, with changes in expression of beclin-1, UV radiation resistance associated gene (UVRAG), autophagy-related protein-5 (Atg5), protein 1 light chain 3 (LC3), sequestosome 1 (p62/SQSTM1) and lysosome-associated membrane protein (LAMP)-1. Conclusions Findings provide evidence that glutamine decreases the inflammatory response and abolishes the changes of the autophagy machinery in patients receiving abdominal RT. The protective effect of glutamine must continue being investigated to disclose further molecular pathways.

Melatonin inhibits the sphingosine kinase 1/sphingosine-1-phosphate signaling pathway in rabbits with fulminant hepatitis of viral origin.

The sphingosine kinase (SphK)1/sphingosine-1-phosphate (S1P) pathway is involved in multiple biological processes, including liver diseases. This study investigate whether modulation of the SphK1/S1P system associates to the beneficial effects of melatonin in an animal model of acute liver failure (ALF) induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received 20 mg/kg of melatonin at 0, 12, and 24 hr postinfection. Liver mRNA levels, protein concentration, and immunohistochemical labeling for SphK1 increased in RHDV-infected rabbits. S1P production and protein expression of the S1PR1 receptor were significantly elevated following RHDV infection. These effects were significantly reduced by melatonin. Rabbits also exhibited increased expression of toll-like receptor (TLR)4, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, nuclear factor-kappa B (NF-κB) p50 and p65 subunits, and phosphorylated inhibitor of kappa B (IκB)α. Melatonin administration significantly inhibited those changes and induced a decreased immunoreactivity for RHDV viral VP60 antigen in the liver. Results obtained indicate that the SphK1/S1P system activates in parallel to viral replication and the inflammatory process induced by the virus. Inhibition of the lipid signaling pathway by the indole reveals novel molecular pathways that may account for the protective effect of melatonin in this animal model of ALF, and supports the potential of melatonin as an antiviral agent.

Melatonin inhibits autophagy and endoplasmic reticulum stress in mice with carbon tetrachloride-induced fibrosis.

This study aimed to investigate whether inhibition of autophagy and endoplasmic reticulum (ER stress) associates with the antifibrogenic effect of melatonin in mice treated with carbon tetrachloride (CCl4 ). Mice received CCl4 5 µL/g body wt i.p. twice a week for 4 wk or 6 wk. Melatonin was given at 5 or 10 mg/kg/day i.p, beginning 2 wk after the start of CCl4 administration. Treatment with CCl4 resulted in fibrosis evidenced by the staining of α-smooth muscle actin (α-SMA)-positive cells. CCl4 induced an autophagic response measured as the presence of autophagic vesicles, protein 1 light chain 3 (LC3) staining, conversion of LC3-I to autophagosome-associated LC3-II, changes in expression of beclin-1, UV radiation resistance-associated gene (UVRAG), ubiquitin-like autophagy-related (Atg5), Atg12, Atg16L1, sequestosome 1 (p62/SQSTM1), and lysosome-associated membrane protein (LAMP)-2, and increased phosphorylation of the mammalian target of rapamycin (mTOR). There was an increase in the expression of the ER stress chaperones CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin-heavy-chain-binding protein (BiP/GRP78), and 94-kDa glucose-regulated protein (GRP94), and in the mRNA levels of pancreatic ER kinase (PERK), activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), and spliced X-box-binding protein-1 (XBP1). Phospho-IRE1, ATF6, and phospho-PERK protein concentration also increased significantly. Immunohistochemical staining of α-SMA indicated an abrogation of hepatic stellate cells activation by melatonin. Furthermore, treatment with the indole resulted in significant inhibition of the autophagic flux and the unfolded protein response. Findings from this study give new insight into molecular pathways accounting for the protective effect of melatonin in fibrogenesis.

Autophagic response in the Rabbit Hemorrhagic Disease, an animal model of virally-induced fulminant hepatic failure.

The Rabbit Hemorrhagic Disease Virus (RHDV) induces a severe disease that fulfils many requirements of an animal model of fulminant hepatic failure. However, a better knowledge of molecular mechanisms contributing to liver damage is required, and it is unknown whether the RHDV induces liver autophagy and how it relates to apoptosis. In this study, we attempted to explore which signalling pathways were involved in the autophagic response induced by the RHDV and to characterize their role in the context of RHDV pathogenesis. Rabbits were infected with 2 × 104 hemmaglutination units of a RHDV isolate. The autophagic response was measured as presence of autophagic vesicles, LC3 staining, conversion of LC3-I to autophagosome-associated LC3-II and changes in expression of beclin-1, UVRAG, Atg5, Atg12, Atg16L1 and p62/SQSTM1. RHDV-triggered autophagy reached a maximum at 24 hours post-infection (hpi) and declined at 30 and 36 hpi. Phosphorylation of mTOR also augmented in early periods of infection and there was an increase in the expression of the endoplasmic reticulum chaperones BiP/GRP78, CHOP and GRP94. Apoptosis, measured as caspase-3 activity and expression of PARP-1, increased significantly at 30 and 36 hpi in parallel to the maximal expression of the RHDV capsid protein VP60. These data indicate that RHDV infection initiates a rapid autophagic response, perhaps in an attempt to protect liver, which associates to ER stress development and is independent from downregulation of the major autophagy suppressor mTOR. As the infection continues and the autophagic response declines, cells begin to exhibit apoptosis.

Melatonin modulates the autophagic response in acute liver failure induced by the rabbit hemorrhagic disease virus.

Autophagy is an important survival pathway and participates in the host response to infection. Beneficial effects of melatonin have been previously reported in an animal model of acute liver failure (ALF) induced by the rabbit hemorrhagic disease virus (RHDV). This study was aimed to investigate whether melatonin protection against liver injury induced by the RHDV associates to modulation of autophagy. Rabbits were infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received 20 mg/kg melatonin at 0, 12, and 24 hr postinfection. RHDV induced autophagy, with increased expression of beclin-1, ubiquitin-like autophagy-related (Atg)5, Atg12, Atg16L1 and sequestrosome 1 (p62/SQSTM1), protein 1 light chain 3 (LC3) staining, and conversion of LC3-I to autophagosome-associated LC3-II. These effects reached a maximum at 24 hr postinfection, in parallel to extensive colocalization of LC3 and lysosome-associated membrane protein (LAMP)-1. The autophagic response induced by RHDV infection was significantly inhibited by melatonin administration. Melatonin treatment also resulted in decreased immunoreactivity for RHDV viral VP60 antigen and a significantly reduction in RHDV VP60 mRNA levels, oxidized to reduced glutathione ratio (GSSG/GSH), caspase-3 activity, and immunoglobulin-heavy-chain-binding protein (BiP) and CCAAT/enhancer-binding protein homologous protein (CHOP) expression. Results indicate that, in addition to its antioxidant and antiapoptotic effects, and the suppression of ER stress, melatonin induces a decrease in autophagy associated with RHDV infection and inhibits RHDV RNA replication. Results obtained reveal novel molecular pathways accounting for the protective effect of melatonin in this animal model of ALF.

Injury characteristics of young elite inline speed skaters: A one season retrospective study.

OBJECTIVES: Determining the rate of injuries related to a certain sport is accepted as the primary step toward designing, implementing and evaluating injury prevention programs. This observational and retrospective study was to examine the injuries sustained by elite young Spanish inline speed skaters during a season. METHODS: Athletes participating in the national championship (n = 80) were surveyed via an anonymous online questionnaire to screen for injury characteristics: incidence, location, and tissue affected; plus training information and demographics. RESULTS: A total of 52 injuries were recorded across 33,351 hours of exposure, which gives a rate of 1.65/1,000 h. The lower body comprised 79% of the total amount of injuries (1.3/1000 h), and the main areas affected were the thigh and foot, accounting for 25% and 19.2% of the recorded injuries, respectively. Musculotendinous injuries were the most frequent, with an incidence of 0.92/1000 h. No significant gender differences were observed for any of the variables studied. CONCLUSION: Speed skating can be considered a low injury rate sport based on our findings. The risk of sustaining an injury was independent of gender, age, and BMI.

Correction: Crespo et al. Protective Effect of Protocatechuic Acid on TNBS-Induced Colitis in Mice Is Associated with Modulation of the SphK/S1P Signaling Pathway. Nutrients 2017, 9, 288.

In the original publication [...].

Melatonin treatment reduces endoplasmic reticulum stress and modulates the unfolded protein response in rabbits with lethal fulminant hepatitis of viral origin.

Hepatocyte apoptosis plays an important role in the development of fulminant hepatic failure (FHF). The objective of this study was to investigate whether endoplasmic reticulum (ER) stress and unfolded protein response (UPR) inhibition is an underlying mechanism of melatonin anti-apoptotic effects in an animal model of FHF of viral origin induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received melatonin at two concentrations of 10 mg/kg and 20 mg/kg at 0 hr, 12 hr and 24 hr postinfection. RHDV infection induced increased expression of CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin heavy chain binding protein (BiP/GRP78), glucose-regulated protein 94 (GRP94), phospho-c-Jun N-terminal kinase (JNK) and caspase-12. These effects were attenuated by melatonin. Double immunofluorescence staining showed colocalization of CHOP and cleaved caspase-3 in liver sections of RHDV-infected rabbits, while immunostaining decreased markedly with melatonin treatment. RHDV infection resulted in significant increases in the mRNA levels of activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), spliced X-box binding protein-1 (XBP1s) and tumor necrosis factor receptor-associated factor 2 (TRAF2). Melatonin attenuated the extent of the changes. Data obtained provide evidence that in rabbits with experimental infection by RHDV, reduction in apoptotic liver damage by melatonin is associated with attenuation of ER stress through a modulation of the three arms of UPR signaling and further support a potential hepatoprotective role of melatonin in FHF.

Cardiotrophin-1 promotes a high survival rate in rabbits with lethal fulminant hepatitis of viral origin.

Rabbit hemorrhagic disease virus (RHDV) causes lethal fulminant hepatitis closely resembling acute liver failure (ALF) in humans. In this study, we investigated whether cardiotrophin-1 (CT-1), a cytokine with hepatoprotective properties, could attenuate liver damage and prolong survival in virus-induced ALF. Twenty-four rabbits were infected with 2 × 10(4) hemagglutination units of RHDV. Twelve received five doses of CT-1 (100 µg/kg) starting at 12 h postinfection (hpi) (the first three doses every 6 h and then two additional doses at 48 and 72 hpi), while the rest received saline. The animals were analyzed for survival, serum biochemistry, and viral load. Another cohort (n = 22) was infected and treated similarly, but animals were sacrificed at 30 and 36 hpi to analyze liver histology, viral load, and the expression of factors implicated in liver damage and repair. All infected rabbits that received saline died by 60 hpi, while 67% of the CT-1-treated animals survived until the end of the study. Treated animals showed improved liver function and histology, while the viral loads were similar. In the livers of CT-1-treated rabbits we observed reduction of oxidative stress, diminished PARP1/2 and JNK activation, and decreased inflammatory reaction, as reflected by reduced expression of tumor necrosis factor alpha, interleukin-1ß, Toll-like receptor 4, VCAM-1, and MMP-9. In addition, CT-1-treated rabbits exhibited marked upregulation of TIMP-1 and increased expression of cytoprotective and proregenerative growth factors, including platelet-derived growth factor B, epidermal growth factor, platelet-derived growth factor receptor ß, and c-Met. In conclusion, in a lethal form of acute viral hepatitis, CT-1 increases animal survival by attenuating inflammation and activating cytoprotective mechanisms, thus representing a promising therapy for ALF of viral origin.