Laboratory parameters related to disease severity and physical performance after reconvalescence of acute COVID-19 infection.

Research into the molecular basis of disease trajectory and Long-COVID is important to get insights toward underlying pathophysiological processes. The objective of this study was to investigate inflammation-mediated changes of metabolism in patients with acute COVID-19 infection and throughout a one-year follow up period. The study enrolled 34 patients with moderate to severe COVID-19 infection admitted to the University Clinic of Innsbruck in early 2020. The dynamics of multiple laboratory parameters (including inflammatory markers [C-reactive protein (CRP), interleukin-6 (IL-6), neopterin] as well as amino acids [tryptophan (Trp), phenylalanine (Phe) and tyrosine (Tyr)], and parameters of iron and vitamin B metabolism) was related to disease severity and patients' physical performance. Also, symptom load during acute illness and at approximately 60 days (FU1), and one year after symptom onset (FU2) were monitored and related with changes of the investigated laboratory parameters: During acute infection many investigated laboratory parameters were elevated (e.g., inflammatory markers, ferritin, kynurenine, phenylalanine) and enhanced tryptophan catabolism and phenylalanine accumulation were found. At FU2 nearly all laboratory markers had declined back to reference ranges. However, kynurenine/tryptophan ratio (Kyn/Trp) and the phenylalanine/tyrosine ratio (Phe/Tyr) were still exceeding the 95th percentile of healthy controls in about two thirds of our cohort at FU2. Lower tryptophan concentrations were associated with B vitamin availability (during acute infection and at FU1), patients with lower vitamin B12 levels at FU1 had a prolonged and more severe impairment of their physical functioning ability. Patients who had fully recovered (ECOG 0) presented with higher concentrations of iron parameters (ferritin, hepcidin, transferrin) and amino acids (phenylalanine, tyrosine) at FU2 compared to patients with restricted ability to work. Persistent symptoms at FU2 were tendentially associated with IFN-γ related parameters. Women were affected by long-term symptoms more frequently. Conclusively, inflammation-mediated biochemical changes appear to be related to symptoms of patients with acute and Long Covid.

Urine Metabolite Analysis to Identify Pathomechanisms of Long COVID: A Pilot Study.

Background: Around 10% of people who had COVID-9 infection suffer from persistent symptoms such as fatigue, dyspnoea, chest pain, arthralgia/myalgia, sleep disturbances, cognitive dysfunction and impairment of mental health. Different underlying pathomechanisms appear to be involved, in particular inflammation, alterations in amino acid metabolism, autonomic dysfunction and gut dysbiosis. Aim: As routine tests are often inconspicuous in patients with Long COVID (LC), similarly to patients suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), accessible biomarkers indicating dysregulation of specific pathways are urgently needed to identify underlying pathomechanisms and enable personalized medicine treatment. Within this pilot study we aimed to proof traceability of altered metabolism by urine analysis. Patients and Methods: Urine metabolome analyses were performed to investigate the metabolic signature of patients with LC (n = 25; 20 women, 5 men) in comparison to healthy controls (Ctrl, n = 8; 7 women, 1 man) and individuals with ME/CFS (n = 8; 2 women, 6 men). Concentrations of neurotransmitter precursors tryptophan, phenylalanine and their downstream metabolites, as well as their association with symptoms (fatigue, anxiety and depression) in the patients were examined. Results and Conclusion: Phenylalanine levels were significantly lower in both the LC and ME/CFS patient groups when compared to the Ctrl group. In many LC patients, the concentrations of downstream metabolites of tryptophan and tyrosine, such as serotonin, dopamine and catecholamines, deviated from the reference ranges. Several symptoms (sleep disturbance, pain or autonomic dysfunction) were associated with certain metabolites. Patients experiencing fatigue had lower levels of kynurenine, phenylalanine and a reduced kynurenine to tryptophan ratio (Kyn/Trp). Lower concentrations of gamma-aminobutyric acid (GABA) and higher activity of kynurenine 3-monooxygenase (KMO) were observed in patients with anxiety. Conclusively, our results suggest that amino acid metabolism and neurotransmitter synthesis is disturbed in patients with LC and ME/CFS. The identified metabolites and their associated dysregulations could serve as potential biomarkers for elucidating underlying pathomechanisms thus enabling personalized treatment strategies for these patient populations.

Positive Effects of Probiotic Therapy in Patients with Post-Infectious Fatigue.

Post-infectious fatigue is a common complication that can lead to decreased physical efficiency, depression, and impaired quality of life. Dysbiosis of the gut microbiota has been proposed as a contributing factor, as the gut-brain axis plays an important role in regulating physical and mental health. This pilot study aimed to investigate the severity of fatigue and depression, as well as the quality of life of 70 patients with post-infectious fatigue who received a multi-strain probiotic preparation or placebo in a double-blind, placebo-controlled trial. Patients completed questionnaires to assess their fatigue (fatigue severity scale (FSS)), mood (Beck Depression Inventory II (BDI-II)), and quality of life (short form-36 (SF-36)) at baseline and after 3 and 6 months of treatment. Routine laboratory parameters were also assessed, including immune-mediated changes in tryptophan and phenylalanine metabolism. The intervention was effective in improving fatigue, mood, and quality of life in both the probiotic and placebo groups, with greater improvements seen in the probiotic group. FSS and BDI-II scores declined significantly under treatment with both probiotics and placebo, but patients who received probiotics had significantly lower FSS (p < 0.001) and BDI-II (p < 0.001) scores after 6 months. Quality of life scores improved significantly in patients who received probiotics (p < 0.001), while patients taking a placebo only saw improvements in the "Physical limitation" and "Energy/Fatigue" subcategories. After 6 months neopterin was higher in patients receiving placebo, while no longitudinal changes in interferon-gamma mediated biochemical pathways were observed. These findings suggest that probiotics may be a promising intervention for improving the health of patients with post-infectious fatigue, potentially through modulating the gut-brain axis.

Tissue iron distribution in patients with anemia of inflammation: Results of a pilot study.

Anemia of inflammation (AI) is frequently present in subjects with inflammatory disorders, primarily caused by inflammation-driven iron retention in macrophages. So far, only limited data on qualitative and quantitative estimates of tissue iron retention in AI patients exist. We performed a prospective cohort study analyzing splenic, hepatic, pancreatic, and cardiac iron content with MRI-based R2*-relaxometry in AI patients, including subjects with concomitant true iron deficiency (AI+IDA) hospitalized between 05/2020-01/2022. Control groups were individuals without inflammation. Spleen R2* values in AI patients with ferritin ≤200 µg/L (AI+IDA) were comparable with those found in controls. In AI patients with ferritin >200 µg/L, spleen (47.6 s-1 vs. 19.3 s-1 , p < .001) and pancreatic R2* values (32.5 s-1 vs. 24.9 s-1 , p = .011) were significantly higher compared with controls, while liver and heart R2*-values did not differ. Higher spleen R2* values were associated with higher ferritin, hepcidin, CRP, and IL-6 concentrations. Spleen R2* values normalized in AI patients after recovery (23.6 s-1 vs. 47.6 s-1 , p = .008), while no changes were found in patients with baseline AI+IDA. This is the first study investigating tissue iron distribution in patients with inflammatory anemia and AI with concomitant true iron deficiency. The results support the findings in animal models demonstrating iron retention in macrophages, which are primarily accumulating in the spleen under inflammatory conditions. MRI-related iron measurement may help to better characterize actual iron needs and to define better biomarker thresholds in the diagnosis of true ID in patients with AI. It may qualify as a useful diagnostic method to estimate the need for iron supplementation and to guide therapy.

Persistent somatic symptoms are key to individual illness perception at one year after COVID-19 in a cross-sectional analysis of a prospective cohort study.

OBJECTIVE: Subjective illness perception (IP) can differ from physician's clinical assessment results. Herein, we explored patient's IP during coronavirus disease 2019 (COVID-19) recovery. METHODS: Participants of the prospective observation CovILD study (ClinicalTrials.gov: NCT04416100) with persistent somatic symptoms or cardiopulmonary findings one year after COVID-19 were analyzed (n = 74). Explanatory variables included demographic and comorbidity, COVID-19 course and one-year follow-up data of persistent somatic symptoms, physical performance, lung function testing, chest computed tomography and trans-thoracic echocardiography. Factors affecting IP (Brief Illness Perception Questionnaire) one year after COVID-19 were identified by regularized modeling and unsupervised clustering. RESULTS: In modeling, 33% of overall IP variance (R2) was attributed to fatigue intensity, reduced physical performance and persistent somatic symptom count. Overall IP was largely independent of lung and heart findings revealed by imaging and function testing. In clustering, persistent somatic symptom count (Kruskal-Wallis test: η2 = 0.31, p < .001), fatigue (η2 = 0.34, p < .001), diminished physical performance (χ2 test, Cramer V effect size statistic: V = 0.51, p < .001), dyspnea (V = 0.37, p = .006), hair loss (V = 0.57, p < .001) and sleep problems (V = 0.36, p = .008) were strongly associated with the concern, emotional representation, complaints, disease timeline and consequences IP dimensions. CONCLUSION: Persistent somatic symptoms rather than abnormalities in cardiopulmonary testing influence IP one year after COVID-19. Modifying IP represents a promising innovative approach to treatment of post-COVID-19 condition. Besides COVID-19 severity, individual IP should guide rehabilitation and psychological therapy decisions.

Impact of Different Isokinetic Movement Patterns on Shoulder Rehabilitation Outcome.

Shoulder pain is regularly associated with limited mobility and limitations in activities of daily living. In occupational therapy, various interventions, including active isokinetic training with a Baltimore Therapeutic Equipment (BTE) Work Simulator, help the patient improve shoulder mobility and alleviate pain. This randomized controlled cohort study aims to evaluate the impact of different isokinetic movement patterns on the DASH score, pain, and objective performance measures, such as range of motion (ROM) and hand grip strength. Patients that participated in a specific 3-week inpatient orthopedic rehabilitation were divided into two groups. The first group (UNI-group, n = 9) carried out uniplanar exercises for shoulder flexion, abduction, and external rotation. The patients in the second group (ADL-group, n = 10) imitated multiplanar everyday movements, such as climbing on a ladder, loading a shopping cart, and raising a glass to their mouth. Compared to the UNI-group, the ADL-group improved significantly in DASH scores (mean -10.92 ± 12.59 vs. -22.83 ± 11.31), pain (NPRS -1.11 ± 2.37 vs. 3.70 ± 2.00), and shoulder abduction (+2.77 ± 15.22 vs. +25.50 ± 21.66 degrees). In conclusion, the specific BTE exercise program with multiplanar movement patterns contributed considerably to the therapeutic improvement.

Quantity of IgG response to SARS-CoV-2 spike glycoprotein predicts pulmonary recovery from COVID-19.

The CovILD study is a prospective, multicenter, observational cohort study to systematically follow up patients after coronavirus disease-2019 (COVID-19). We extensively evaluated 145 COVID-19 patients at 3 follow-up visits scheduled for 60, 100, and 180 days after initial confirmed diagnosis based on typical symptoms and a positive reverse transcription-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We employed comprehensive pulmonary function and laboratory tests, including serum concentrations of IgG against the viral spike (S) glycoprotein, and compared the results to clinical data and chest computed tomography (CT). We found that at the 60 day follow-up, 131 of 145 (90.3%) participants displayed S-specific serum IgG levels above the cut-off threshold. Notably, the highly elevated IgG levels against S glycoprotein positively correlated with biomarkers of immune activation and negatively correlated with pulmonary function and the extent of pulmonary CT abnormalities. Based on the association between serum S glycoprotein-specific IgG and clinical outcome, we generated an S-specific IgG-based recovery score that, when applied in the early convalescent phase, accurately predicted delayed pulmonary recovery after COVID-19. Therefore, we propose that S-specific IgG levels serve as a useful immunological surrogate marker for identifying at-risk individuals with persistent pulmonary injury who may require intensive follow-up care after COVID-19.

Dynamics in Anemia Development and Dysregulation of Iron Homeostasis in Hospitalized Patients with COVID-19.

Anemia and disturbances of iron metabolism are frequently encountered in patients with COVID-19 and associated with an adverse clinical course. We retrospectively analyzed 645 consecutive COVID-19 patients hospitalized at the Innsbruck University Hospital. Pre-existing anemia was associated with increased risk for in-hospital death. We further found that the decline in hemoglobin levels during hospital stay is more pronounced in patients with signs of hyperinflammation upon admission, the latter being associated with a nearly two-fold higher risk for new onset anemia within one week. Anemia prevalence increased from 44.3% upon admission to 87.8% in patients who were still hospitalized after two weeks. A more distinct decrease in hemoglobin levels was observed in subjects with severe disease, and new-onset anemia was associated with a higher risk for ICU admission. Transferrin levels decreased within the first week of hospitalization in all patients, however, a continuous decline was observed in subjects who died. Hemoglobin, ferritin, and transferrin levels normalized in a median of 122 days after discharge from hospital. This study uncovers pre-existing anemia as well as low transferrin concentrations as risk factors for mortality in hospitalized COVID-19 patients, whereas new-onset anemia during hospitalization is a risk factor for ICU admission. Anemia and iron disturbances are mainly driven by COVID-19 associated inflammation, and cure from infection results in resolution of anemia and normalization of dysregulated iron homeostasis.

Regulation of Th1 T Cell Differentiation by Iron via Upregulation of T Cell Immunoglobulin and Mucin Containing Protein-3 (TIM-3).

Iron plays an important role in host-pathogen interactions, in being an essential element for both pathogen and host metabolism, but also by impacting immune cell differentiation and anti-microbial effector pathways. Iron has been implicated to affect the differentiation of T lymphocytes during inflammation, however, so far the underlying mechanism remained elusive. In order to study the role of iron in T cell differentiation we here investigated how dietary iron supplementation affects T cell function and outcome in a model of chronic infection with the intracellular bacterium Salmonella enterica serovar typhimurium (S. Typhimurium). Iron loading prior to infection fostered bacterial burden and, unexpectedly, reduced differentiation of CD4+ T helper cells type 1 (Th1) and expression of interferon-gamma (IFNγ), a key cytokine to control infections with intracellular pathogens. This effect could be traced back to iron-mediated induction of the negative immune checkpoint regulator T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), expressed on the surface of this T cell subset. In vitro experiments demonstrated that iron supplementation specifically upregulated mRNA and protein expression of TIM-3 in naïve Th cells in a dose-depdendent manner and hindered priming of those T cells towards Th1 differentiation. Importantly, administration of TIM-3 blocking antibodies to iron-loaded mice infected with S. Typhimurium virtually restored Th1 cell differentiation and significantly improved bacterial control. Our data uncover a novel mechanism by which iron modulates CD4+ cell differentiation and functionality and hence impacts infection control with intracellular pathogens. Specifically, iron inhibits the differentiation of naive CD4+ T cells to protective IFNγ producing Th1 lymphocytes via stimulation of TIM-3 expression. Finally, TIM-3 may serve as a novel drug target for the treatment of chronic infections with intracellular pathogens, specifically in iron loading diseases.

Overcoming limitations in the availability of swabs systems used for SARS-CoV-2 laboratory diagnostics.

The diagnosis of COVID-19 relies on the direct detection of SARS-CoV-2 RNA in respiratory specimens by RT-PCR. The pandemic spread of the disease caused an imbalance between demand and supply of materials and reagents needed for diagnostic purposes including swab sets. In a comparative effectiveness study, we conducted serial follow-up swabs in hospitalized laboratory-confirmed COVID-19 patients. We assessed the diagnostic performance of an in-house system developed according to recommendations by the US CDC. In a total of 96 serial swabs, we found significant differences in the accuracy of the different swab systems to generate a positive result in SARS-CoV-2 RT-PCR, ranging from around 50 to 80%. Of note, an in-house swab system was superior to most commercially available sets as reflected by significantly lower Ct values of viral genes. Thus, a simple combination of broadly available materials may enable diagnostic laboratories to bypass global limitations in the supply of swab sets.

Neopterin Predicts Disease Severity in Hospitalized Patients With COVID-19.

This study evaluates the predictive value of circulating inflammatory markers, especially neopterin, in patients with coronavirus disease 2019 (COVID-19). Within this retrospective analysis of 115 hospitalized COVID-19 patients, elevated neopterin levels upon admission were significantly associated with disease severity, risk for intensive care unit admission, need for mechanical ventilation, and death. Therefore, neopterin is a reliable predictive marker in patients with COVID-19 and may help to improve the clinical management of patients.

Cell-specific expression of Hfe determines the outcome of Salmonella enterica serovar Typhimurium infection in mice

Mutations in HFE cause hereditary hemochromatosis type I hallmarked by increased iron absorption, iron accumulation in hepatocytes and iron deficiency in myeloid cells. HFE encodes an MHC-I like molecule, but its function in immune responses to infection remains incompletely understood. Here, we investigated putative roles of Hfe in myeloid cells and hepatocytes, separately, upon infection with Salmonella Typhimurium, an intracellular bacterium with iron-dependent virulence. We found that constitutive and macrophage-specific deletion of Hfe protected infected mice. The propagation of Salmonella in macrophages was reduced due to limited intramacrophage iron availability for bacterial growth and increased expression of the anti-microbial enzyme nitric oxide synthase-2. By contrast, mice with hepatocyte-specific deletion of Hfe succumbed earlier to Salmonella infection because of unrestricted extracellular bacterial replication associated with high iron availability in the serum and impaired expression of essential host defense molecules such as interleukin-6, interferon-γ and nitric oxide synthase-2. Wild-type mice subjected to dietary iron overload phenocopied hepatocyte-specific Hfe deficiency suggesting that increased iron availability in the serum is deleterious in Salmonella infection and underlies impaired host immune responses. Moreover, the macrophage-specific effect is dominant over hepatocyte-specific Hfe-depletion, as Hfe knock-out mice have increased survival despite the higher parenchymal iron load associated with systemic loss of Hfe. We conclude that cell-specific expression of Hfe in hepatocytes and macrophages differentially affects the course of infections with specific pathogens by determining bacterial iron access and the efficacy of anti-microbial immune effector pathways. This may explain the high frequency and evolutionary conservation of human HFE mutations.

Cardiopulmonary recovery after COVID-19: an observational prospective multicentre trial.

BACKGROUND: After the 2002/2003 severe acute respiratory syndrome outbreak, 30% of survivors exhibited persisting structural pulmonary abnormalities. The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) are yet unknown, and comprehensive clinical follow-up data are lacking. METHODS: In this prospective, multicentre, observational study, we systematically evaluated the cardiopulmonary damage in subjects recovering from COVID-19 at 60 and 100 days after confirmed diagnosis. We conducted a detailed questionnaire, clinical examination, laboratory testing, lung function analysis, echocardiography and thoracic low-dose computed tomography (CT). RESULTS: Data from 145 COVID-19 patients were evaluated, and 41% of all subjects exhibited persistent symptoms 100 days after COVID-19 onset, with dyspnoea being most frequent (36%). Accordingly, patients still displayed an impaired lung function, with a reduced diffusing capacity in 21% of the cohort being the most prominent finding. Cardiac impairment, including a reduced left ventricular function or signs of pulmonary hypertension, was only present in a minority of subjects. CT scans unveiled persisting lung pathologies in 63% of patients, mainly consisting of bilateral ground-glass opacities and/or reticulation in the lower lung lobes, without radiological signs of pulmonary fibrosis. Sequential follow-up evaluations at 60 and 100 days after COVID-19 onset demonstrated a vast improvement of symptoms and CT abnormalities over time. CONCLUSION: A relevant percentage of post-COVID-19 patients presented with persisting symptoms and lung function impairment along with radiological pulmonary abnormalities >100 days after the diagnosis of COVID-19. However, our results indicate a significant improvement in symptoms and cardiopulmonary status over time.

The haemochromatosis gene Hfe and Kupffer cells control LDL cholesterol homeostasis and impact on atherosclerosis development.

AIMS: Imbalances of iron metabolism have been linked to the development of atherosclerosis. However, subjects with hereditary haemochromatosis have a lower prevalence of cardiovascular disease. The aim of our study was to understand the underlying mechanisms by combining data from genome-wide association study analyses in humans, CRISPR/Cas9 genome editing, and loss-of-function studies in mice. METHODS AND RESULTS: Our analysis of the Global Lipids Genetics Consortium (GLGC) dataset revealed that single nucleotide polymorphisms (SNPs) in the haemochromatosis gene HFE associate with reduced low-density lipoprotein cholesterol (LDL-C) in human plasma. The LDL-C lowering effect could be phenocopied in dyslipidaemic ApoE-/- mice lacking Hfe, which translated into reduced atherosclerosis burden. Mechanistically, we identified HFE as a negative regulator of LDL receptor expression in hepatocytes. Moreover, we uncovered liver-resident Kupffer cells (KCs) as central players in cholesterol homeostasis as they were found to acquire and transfer LDL-derived cholesterol to hepatocytes in an Abca1-dependent fashion, which is controlled by iron availability. CONCLUSION: Our results disentangle novel regulatory interactions between iron metabolism, KC biology and cholesterol homeostasis which are promising targets for treating dyslipidaemia but also provide a mechanistic explanation for reduced cardiovascular morbidity in subjects with haemochromatosis.

Newly emerging ulceroglandular tularaemia in Western Austria.

Tularaemia is a rare zoonotic disease caused by Francisella tularensis in humans. In Europe infections of humans and animals are mainly caused by F. tularensis subspecies holarctica. We report the first three documented cases of tularaemia in humans in Western Austria.

Iron and innate antimicrobial immunity-Depriving the pathogen, defending the host.

The acute-phase response is triggered by the presence of infectious agents and danger signals which indicate hazards for the integrity of the mammalian body. One central feature of this response is the sequestration of iron into storage compartments including macrophages. This limits the availability of this essential nutrient for circulating pathogens, a host defence strategy known as 'nutritional immunity'. Iron metabolism and the immune response are intimately linked. In infections, the availability of iron affects both the efficacy of antimicrobial immune pathways and pathogen proliferation. However, host strategies to withhold iron from microbes vary according to the localization of pathogens: Infections with extracellular bacteria such as Staphylococcus aureus, Streptococcus, Klebsiella or Yersinia stimulate the expression of the iron-regulatory hormone hepcidin which targets the cellular iron-exporter ferroportin-1 causing its internalization and blockade of iron egress from absorptive enterocytes in the duodenum and iron-recycling macrophages. This mechanism disrupts both routes of iron delivery to the circulation, contributes to iron sequestration in the mononuclear phagocyte system and mediates the hypoferraemia of the acute phase response subsequently resulting in the development of anaemia of inflammation. When intracellular microbes are present, other strategies of microbial iron withdrawal are needed. For instance, in macrophages harbouring intracellular pathogens such as Chlamydia, Mycobacterium tuberculosis, Listeria monocytogenes or Salmonella Typhimurium, ferroportin-1-mediated iron export is turned on for the removal of iron from infected cells. This also leads to reduced iron availability for intra-macrophage pathogens which inhibits their growth and in parallel strengthens anti-microbial effector pathways of macrophages including the formation of inducible nitric oxide synthase and tumour necrosis factor. Iron plays a key role in infectious diseases both as modulator of the innate immune response and as nutrient for microbes. We need to gain a more comprehensive understanding of how the body can differentially respond to infection by extra- or intracellular pathogens. This knowledge may allow us to modulate mammalian iron homeostasis pharmaceutically and to target iron-acquisition systems of pathogens, thus enabling us to treat infections with novel strategies that act independent of established antimicrobials.

Cibinetide dampens innate immune cell functions thus ameliorating the course of experimental colitis.

Two distinct forms of the erythropoietin receptor (EPOR) mediate the cellular responses to erythropoietin (EPO) in different tissues. EPOR homodimers signal to promote the maturation of erythroid progenitor cells. In other cell types, including immune cells, EPOR and the ß-common receptor (CD131) form heteromers (the innate repair receptor; IRR), and exert tissue protective effects. We used dextran sulphate sodium (DSS) to induce colitis in C57BL/6 N mice. Once colitis was established, mice were treated with solvent, EPO or the selective IRR agonist cibinetide. We found that both cibinetide and EPO ameliorated the clinical course of experimental colitis in mice, resulting in improved weight gain and survival. Correspondingly, DSS-exposed mice treated with cibinetide or EPO displayed preserved tissue integrity due to reduced infiltration of myeloid cells and diminished production of pro-inflammatory disease mediators including cytokines, chemokines and nitric oxide synthase-2. Experiments using LPS-activated primary macrophages revealed that the anti-inflammatory effects of cibinetide were dependent on CD131 and JAK2 functionality and were mediated via inhibition of NF-κB subunit p65 activity. Cibinetide activation of the IRR exerts potent anti-inflammatory effects, especially within the myeloid population, reduces disease activity and mortality in mice. Cibinetide thus holds promise as novel disease-modifying therapeutic of inflammatory bowel disease.

Genetic and Dietary Iron Overload Differentially Affect the Course of Salmonella Typhimurium Infection.

Genetic and dietary forms of iron overload have distinctive clinical and pathophysiological features. HFE-associated hereditary hemochromatosis is characterized by overwhelming intestinal iron absorption, parenchymal iron deposition, and macrophage iron depletion. In contrast, excessive dietary iron intake results in iron deposition in macrophages. However, the functional consequences of genetic and dietary iron overload for the control of microbes are incompletely understood. Using Hfe+/+ and Hfe-/- mice in combination with oral iron overload in a model of Salmonella enterica serovar Typhimurium infection, we found animals of either genotype to induce hepcidin antimicrobial peptide expression and hypoferremia following systemic infection in an Hfe-independent manner. As predicted, Hfe-/- mice, a model of hereditary hemochromatosis, displayed reduced spleen iron content, which translated into improved control of Salmonella replication. Salmonella adapted to the iron-poor microenvironment in the spleens of Hfe-/- mice by inducing the expression of its siderophore iron-uptake machinery. Dietary iron loading resulted in higher bacterial numbers in both WT and Hfe-/- mice, although Hfe deficiency still resulted in better pathogen control and improved survival. This suggests that Hfe deficiency may exert protective effects in addition to the control of iron availability for intracellular bacteria. Our data show that a dynamic adaptation of iron metabolism in both immune cells and microbes shapes the host-pathogen interaction in the setting of systemic Salmonella infection. Moreover, Hfe-associated iron overload and dietary iron excess result in different outcomes in infection, indicating that tissue and cellular iron distribution determines the susceptibility to infection with specific pathogens.

Metallothioneins and renal ageing.

BACKGROUND: Human lifespan is increasing continuously and about one-third of the population >70 years of age suffers from chronic kidney disease. The pathophysiology of the loss of renal function with ageing is unclear. METHODS: We determined age-associated gene expression changes in zero-hour biopsies of deceased donor kidneys without laboratory signs of impaired renal function, defined as a last serum creatinine >0.96 mg/dL in females and >1.18 mg/dL in males, using microarray technology and the Significance Analysis of Microarrays routine. Expression changes of selected genes were confirmed by quantitative polymerase chain reaction and in situ hybridization and immunohistochemistry for localization of respective mRNA and protein. Functional aspects were examined in vitro. RESULTS: Donors were classified into three age groups (<40, 40-59 and >59 years; Groups 1, 2 and 3, respectively). In Group 3 especially, genes encoding for metallothionein (MT) isoforms were more significantly expressed when compared with Group 1; localization studies revealed predominant staining in renal proximal tubular cells. RPTEC/TERT1 cells overexpressing MT2A were less susceptible towards cadmium chloride-induced cytotoxicity and hypoxia-induced apoptosis, both models for increased generation of reactive oxygen species. CONCLUSIONS: Increased expression of MTs in the kidney with ageing might be a protective mechanism against increased oxidative stress, which is closely related to the ageing process. Our findings indicate that MTs are functionally involved in the pathophysiology of ageing-related processes.

Lipocalin-2 ensures host defense against Salmonella Typhimurium by controlling macrophage iron homeostasis and immune response.

Lipocalin-2 (Lcn2) is an innate immune peptide with pleiotropic effects. Lcn2 binds iron-laden bacterial siderophores, chemo-attracts neutrophils and has immunomodulatory and apoptosis-regulating effects. In this study, we show that upon infection with Salmonella enterica serovar Typhimurium, Lcn2 promotes iron export from Salmonella-infected macrophages, which reduces cellular iron content and enhances the generation of pro-inflammatory cytokines. Lcn2 represses IL-10 production while augmenting Nos2, TNF-α, and IL-6 expression. Lcn2(-/-) macrophages have elevated IL-10 levels as a consequence of increased iron content. The crucial role of Lcn-2/IL-10 interactions was further demonstrated by the greater ability of Lcn2(-/-) IL-10(-/-) macrophages and mice to control intracellular Salmonella proliferation in comparison to Lcn2(-/-) counterparts. Overexpression of the iron exporter ferroportin-1 in Lcn2(-/-) macrophages represses IL-10 and restores TNF-α and IL-6 production to the levels found in wild-type macrophages, so that killing and clearance of intracellular Salmonella is promoted. Our observations suggest that Lcn2 promotes host resistance to Salmonella Typhimurium infection by binding bacterial siderophores and suppressing IL-10 production, and that both functions are linked to its ability to shuttle iron from macrophages.