The acute phase response and the hematopoietic system: the role of cytokines

The Role of Aspartate Transaminase to Platelet Ratio Index (APRI) for the Prediction of Non-Alcoholic Fatty Liver Disease (NAFLD) in Severely Obese Children and Adolescents

The aspartate transaminase to platelet ratio index (APRI) has been proposed as an easy-to-use biochemical marker in obese adults with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatotic hepatitis (NASH). The objective of the present study was to evaluate the clinical and predictive value of APRI in a paediatric obese population. Seven hundred fifty-seven obese children and adolescents (BMI standard deviation score, SDS: >2.0; age range: 10–18.5 years), not consuming alcohol and without hepatitis B or C, were recruited after having been screened for NAFLD by ultrasonography. A series of demographic, biochemical and clinical parameters was compared between the two subgroups (with or without NAFLD); the same parameters were correlated with APRI; and finally, univariable and multivariable logistic regression was used to evaluate the predictors of NAFLD. NAFLD was diagnosed in about 39% of the entire paediatric population, predominantly in males and in subjects suffering from metabolic syndrome. APRI was correlated with the waist circumference (WC), high-density lipoprotein cholesterol (HDL-C), uric acid, total bilirubin, C reactive protein (CRP) and systolic blood pressure (SBP). Furthermore, APRI was higher in males than females, but independent from steatosis severity and metabolic syndrome. With the univariable analysis, the BMI SDS, triglycerides (TG), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), APRI, uric acid and metabolic syndrome were positive predictors of NAFLD, with female sex being negative predictor. At multivariable analysis; however, only BMI SDS, TG, HOMA-IR and APRI were positive predictors of NAFLD, with female sex being a negative predictor. The accuracy of APRI as a biochemical marker of NAFLD was about 60%.In conclusion, in a large (Italian) paediatric obese population, parameters, such as BMI SDS, TG, HOMA-IR and APRI, were positive predictors of NAFLD, with female sex being a negative predictor and most of the prediction explained by APRI. Nevertheless, APRI appears to be a simple biochemical marker of liver injury rather than of NAFLD/NASH and, moreover, is endowed with a limited accuracy for the prediction/diagnosis of NAFLD.

Systemic effects of IL-6 blockade in rheumatoid arthritis beyond the joints

Interleukin (IL)-6 is produced locally in response to an inflammatory stimulus, and is able to induce systemic manifestations at distance from the site of inflammation. Its unique signaling mechanism, including classical and trans-signaling pathways, leads to a major expansion in the number of cell types responding to IL-6. This pleiotropic cytokine is a key factor in the pathogenesis of rheumatoid arthritis (RA) and is involved in many extra-articular manifestations that accompany the disease. Thus, IL-6 blockade is associated with various biological effects beyond the joints. In this review, the systemic effects of IL-6 in RA comorbidities and the consequences of its blockade will be discussed, including anemia of chronic disease, cardiovascular risks, bone and muscle functions, and neuro-psychological manifestations.

Effect of Escherichia coli lipopolysaccharide challenge on eggshell, tibia, and keel bone attributes in ISA brown hens exposed to dietary n-3 fatty acids prior to onset of lay

The impact of Escherichia coli lipopolysaccharide (LPS) challenge on eggshell, tibia, and keel bone characteristics in ISA brown hens derived from breeders and pullets fed omega-3 polyunsaturated fatty acids (n-3 PUFA) was examined. The breeders were fed the following diets: 1) Control (CON); 2) CON + 1% microalgae as the source of docosahexaenoic acid (DHA); and 3) CON + 2.6% of a co-extruded mixture of full-fat flaxseed and pulses as a source of α-linolenic acid (ALA). During the pullet phase, offspring from breeders fed CON were fed CON or supplemented diets, and offspring from supplemented diets either continued with respective n-3 PUFA diets or CON. At 18 weeks of age (WOA), pullets were fed a common layer diet to 42 WOA. A total of 5 birds were selected based on the average body weight (BW) of each treatment and moved to an individual cage at 41 WOA. Three days before the end of 42 WOA, all the birds were weighed and subcutaneously injected with either saline or 4 mg LPS/kg BW. Eggs were recorded, labeled, and kept for egg quality analyses. At 42 WOA, birds were necropsied for tibia and keel bone samples. Administration of LPS reduced eggshell breaking strength, eggshell weight, tibia, and keel bone ash content (P < 0.05). Specifically, LPS challenged hens had 14.9, 11.1, 9.2, and 11.6% lower eggshell breaking strength, eggshell weight, keel, and tibia ash content, respectively relative to unchallenged hens. Hens from breeders and pullets fed n-3 PUFA had similar (P > 0.05) eggshell, tibia, and keel bone attributes to control hens. In conclusion, the provision of ALA and DHA to breeders and their offspring did not alleviate the negative effects of LPS on eggshell, tibia, and keel bone characteristics in laying hens.

The Presence of Circulating Nucleated Red Blood Cells Is Associated With Disease Severity in Patients of Hemorrhagic Fever With Renal Syndrome

Hemorrhagic fever with renal syndrome (HFRS) is a regional infectious disease of epidemic potential caused by the Hantaan virus (HTNV). Red blood cells (RBCs) are the major components of peripheral blood. However, pathological changes in RBCs and the underlying mechanisms during HTNV infection remain largely unclear. Therefore, this study sought to explore changes in RBCs in the peripheral blood of HFRS patients. We isolated PBMCs from HFRS patients and performed single-cell RNA sequencing. The results showed that clusters of RBCs in the peripheral blood of HFRS could be classified as nucleated red blood cells (NRBC) based on their cellular components, gene expression profiles and cell surface markers. In addition, it was shown that the higher the count of NRBC in peripheral blood, the more severe the disease status was. Moreover, hematological indices related to RBCs were analyzed and the results showed that impairment in the folate pathway might be the possible reason behind the presence of NRBCs. This study, for the first time showed that the presence of NRBCs in the peripheral blood of HFRS patients was associated with disease severity. This was also the first study to show that infection with the HTNV virus hindered the maturation of RBCs. Therefore, this work provides further insights on the role of and pathological changes in RBCs during HTNV infection.

Air pollutants disrupt iron homeostasis to impact oxidant generation, biological effects, and tissue injury

Air pollutants cause changes in iron homeostasis through: 1) a capacity of the pollutant, or a metabolite(s), to complex/chelate iron from pivotal sites in the cell or 2) an ability of the pollutant to displace iron from pivotal sites in the cell. Through either pathway of disruption in iron homeostasis, metal previously employed in essential cell processes is sequestered after air pollutant exposure. An absolute or functional cell iron deficiency results. If enough iron is lost or is otherwise not available within the cell, cell death ensues. However, prior to death, exposed cells will attempt to reverse the loss of requisite metal. This response of the cell includes increased expression of metal importers (e.g. divalent metal transporter 1). Oxidant generation after exposure to air pollutants includes superoxide production which functions in ferrireduction necessary for cell iron import. Activation of kinases and phosphatases and transcription factors and increased release of pro-inflammatory mediators also result from a cell iron deficiency, absolute or functional, after exposure to air pollutants. Finally, air pollutant exposure culminates in the development of inflammation and fibrosis which is a tissue response to the iron deficiency challenging cell survival. Following the response of increased expression of importers and ferrireduction, activation of kinases and phosphatases and transcription factors, release of pro-inflammatory mediators, and inflammation and fibrosis, cell iron is altered, and a new metal homeostasis is established. This new metal homeostasis includes increased total iron concentrations in cells with metal now at levels sufficient to meet requirements for continued function.

Plasma proteomic profiling and pathway analysis of normal and overconditioned dairy cows during the transition from late pregnancy to early lactation

This study applied a quantitative proteomics approach along with bioinformatics analyses to investigate changes in the plasma proteome of normal and overconditioned dairy cows during the transition period. Fifteen weeks before their anticipated calving date, 38 multiparous Holstein cows were selected based on their current and previous body condition scores (BCS) and allocated to either a high or a normal BCS group (19 cows each). They received different diets until dry-off to reach targeted differences in BCS and back fat thickness (BFT) until dry-off. At dry-off, normal BCS cows had a BCS <3.5 (minimum, 2.75) and BFT <1.2 cm (minimum, 0.58), and the high BCS cows had a BCS >3.75 (maximum, 4.50) and BFT >1.4 cm (maximum, 2.90). The proteomics study used a subset of 5 animals from each group. These cows were selected based on their circulating concentrations of fatty acids (FA) on d 14 postpartum and β-hydroxybutyrate (BHB) on d 21 postpartum, representing the greater or the lower extreme values within their BCS group, respectively. The high BCS subset (HE-HBCS) had 4.50 < BCS > 3.75, FA = 1.17 ± 0.46 mmol/L, and BHB = 2.15 ± 0.42 mmol/L (means ± SD), and the low BCS subset (LE-NBCS) had 3.50 < BCS > 2.75, FA = 0.51 ± 0.28 mmol/L, and BHB = 0.84 ± 0.17 mmol/L. Plasma samples from d -49, +7, and +21 relative to parturition were used for proteome profiling by applying the quantitative tandem mass tags (TMT) approach. Nondepleted plasma samples were subjected to reduction and digestion and then labeled with TMT 10plex reagents. High-resolution liquid chromatography-tandem mass spectrometry analysis of TMT-labeled peptides was carried out, and the acquired spectra were analyzed for protein identification and quantification. In total, 254 quantifiable proteins (criteria: 2 unique peptides and 5% false discovery rate) were identified in the plasma samples. From these, 24 differentially abundant proteins (14 more abundant, 10 less abundant) were observed in the LE-NBCS cows compared with the HE-HBCS cows during the transition period. Plasma α-2-macroglobulins were more abundant in HE-HBCS versus LE-NBCS cows at d +7 and +21. Gene Ontology enrichment analyses of differentially abundant proteins revealed that the acute inflammatory response, regulation of complement activation, protein activation cascade, and regulation of humoral immune response were the most enriched terms in the LE-NBCS group compared with the HE-HBCS group. In addition, we identified 24 differentially abundant proteins (16 in the LE-NBCS group, and 8 in the HE-HBCS group) during the transition period. The complement components C1q and C5 were less abundant, while C3 and C3d were more abundant in LE-NBCS compared with HE-HBCS cows. Overall, overconditioning around calving was associated with alterations in protein pathways related to acute inflammatory response and regulation of complement and coagulation cascades in transition cows.

The Influence of Inflammation on Anemia in CKD Patients

Anemia is frequently observed in the course of chronic kidney disease (CKD) and it is associated with diminishing the quality of a patient’s life. It also enhances morbidity and mortality and hastens the CKD progression rate. Patients with CKD frequently suffer from a chronic inflammatory state which is related to a vast range of underlying factors. The results of studies have demonstrated that persistent inflammation may contribute to the variability in Hb levels and hyporesponsiveness to erythropoietin stimulating agents (ESA), which are frequently observed in CKD patients. The understanding of the impact of inflammatory cytokines on erythropoietin production and hepcidin synthesis will enable one to unravel the net of interactions of multiple factors involved in the pathogenesis of the anemia of chronic disease. It seems that anti-cytokine and anti-oxidative treatment strategies may be the future of pharmacological interventions aiming at the treatment of inflammation-associated hyporesponsiveness to ESA. The discovery of new therapeutic approaches towards the treatment of anemia in CKD patients has become highly awaited. The treatment of anemia with erythropoietin (EPO) was associated with great benefits for some patients but not all.

Comparative evaluation of C-reactive protein and complete blood count in chronic periodontitis patients following Phase I therapy: A serological and hematological study

Background

Periodontitis is an example of persistent low-grade disease. The primary cause for the disease is anaerobic gram-negative bacteria thriving in a protective biofilm in subgingival periodontal pockets. The treatment of this infection is removal of these deposits by mechanical instrumentation (Phase I therapy). This can help achieve reduction of the bacterial load thus suppressing localized inflammation. Phase I therapy or mechanical debridement of the subgingival area causes a severe transient bacteremia along with some damage to the surrounding soft tissue, resulting in a systemic inflammatory response being elicited. The objective of the current study was to comparatively assess periodontal parameters, serum C-reactive protein (CRP) levels, and transitory alterations in hematological parameters; in 30-systemically healthy patients having chronic periodontitis, before and after Phase I therapy.

Materials and Method

The individuals underwent an intensive session of mechanotherapy with ultrasonic scalers. Blood samples were taken before treatment and at 1, 7, and 30 days after treatment to assess the parameters.

Results

There was a clear recuperation in periodontal parameters as well as marked improvement in the values of CRP and complete blood count (CBC) by 30 days after transient alterations occurring initially.

Conclusion

Phase I (mechanotherapy) - the first step in treatment of periodontitis leads to transient bacteremia by systemic dispersal of bacteria harbored in dental plaque. This produces an acute-phase response resulting in variations in the levels of CRP and the CBC counts. After a month, both periodontal and hematological parameters show marked improvement, thus establishing periodontal health and decreasing the risk of inadvertent cardiovascular or thromboembolic episode.

Iron Deficiency in the Acute-Phase Reaction After Open Aortic Surgery

The objective of this study was to quantify the magnitude of iron deficiency in the postoperative period after open aortic surgery. This was a prospective observational study in 55 consecutive patients. Blood samples were obtained on postoperative days 1, 2, 4, 30, and 45, and the parameters determined were the following: iron, transferrin, transferrin saturation index, transferrin-soluble receptor, ferritin, red cell count, hemoglobin, hematocrit, serum C-reactive protein, fibrinogen, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and number of blood units transfused. We performed statistical ANOVA test for repetitive measurements (lower bound) in regard to its basal level. Iron deficiency and its parameters reached the maximum at 48 hours postoperatively (iron: 18.92 g/dL and transferrin saturation index: 11.1%) (P <.05). There was not a complete recovery after 45 days (iron: 51.23 g/dL and transferrin saturation index: 18.0%) (P <.05). A similar evolution was observed in the other measured parameters (red cell count: 3.5 x 106/L.; hemoglobin: 10.4 g/dL; hematocrit: 30.7%) (P <.005), none affecting the values of concentration or volume (P <.05). Transferrin-soluble receptors, normal at first, were increased at postoperative days 30 and 45 (2.7 and 2.4 mg/dL respectively, P <.005). After open aortic surgery there is an important acute-phase reaction, a dramatic iron deficiency, and a lack of its transporters until the 45th analyzed day. The elevation of transferrin-soluble receptors in the 4th and 6th weeks denotes a necessity of iron supplementation for a correct development of the immature hematic cells since blood parameters do not reach normal levels in the 6th postoperative week.

Associations between Common Variants in Iron-Related Genes with Haematological Traits in Populations of African Ancestry

BACKGROUND

Large genome-wide association (GWA) studies of European ancestry individuals have identified multiple genetic variants influencing iron status. Studies on the generalizability of these associations to African ancestry populations have been limited. These studies are important given interethnic differences in iron status and the disproportionate burden of iron deficiency among African ancestry populations.

METHODS

We tested the associations of 20 previously identified iron status-associated single nucleotide polymorphisms (SNPs) in 628 Kenyans, 609 Tanzanians, 608 South Africans and 228 African Americans. In each study, we examined the associations present between 20 SNPs with ferritin and haemoglobin, adjusting for age, sex and CRP levels.

RESULTS

In the meta analysis including all 4 African ancestry cohorts, we replicated previously reported associations with lowered haemoglobin concentrations for rs2413450 (β = -0.19, P = 0.02) and rs4820268 (β = -0.16, P = 0.04) in TMPRSS6. An association with increased ferritin concentrations was also confirmed for rs1867504 in TF (β = 1.04, P = <0.0001) in the meta analysis including the African cohorts only.

CONCLUSIONS

In all meta analyses, we only replicated 4 of the 20 single nucleotide polymorphisms reported to be associated with iron status in large GWA studies of European ancestry individuals. While there is now evidence for the associations of a number of genetic variants with iron status in both European and African ancestry populations, the considerable lack of concordance highlights the importance of continued ancestry-specific studies to elucidate the genetic underpinnings of iron status in ethnically diverse populations.

Transferrin Saturation: A Body Iron Biomarker

Iron is an essential element for several metabolic pathways and physiological processes. The maintenance of iron homeostasis within the human body requires a dynamic and highly sophisticated interplay of several proteins, as states of iron deficiency or excess are both potentially deleterious to health. Among these is plasma transferrin, which is central to iron metabolism not only through iron transport between body tissues in a soluble nontoxic form but also through its protective scavenger role in sequestering free toxic iron. The transferrin saturation (TSAT), an index that takes into account both plasma iron and its main transport protein, is considered an important biochemical marker of body iron status. Its increasing use in many health systems is due to the increased availability of measurement methods, such as calorimetry, turbidimetry, nephelometry, and immunochemistry to estimate its value. However, despite its frequent use in clinical practice to detect states of iron deficiency or iron overload, careful attention should be paid to the inherent limitations of the test especially in certain settings such as inflammation in order to avoid misinterpretation and erroneous conclusions. Beyond its usual clinical use, an emerging body of evidence has linked TSAT levels to major clinical outcomes such as cardiovascular mortality. This has the potential to extend the utility of TSAT index to risk stratification and prognostication. However, most of the current evidence is mainly driven by observational studies where the risk of residual confounding cannot be fully eliminated. Indeed, future efforts are required to fully explore this capability in well-designed clinical trials or prospective large-scale cohorts.

Haemoglobin mass alterations in healthy humans following four-day head-down tilt bed rest

NEW FINDINGS

What is the central question of this study? Is haemoglobin mass (Hbmass) decreased following 4 days of head-down tilt bed rest (HDTBR), and does increased red blood cell (RBC) destruction mediate this adaptation? What is the main finding and its importance? Haemoglobin mass was increased immediately following HDTBR, before decreasing below baseline 5 days after return to normal living conditions. The transient increase in Hbmass might be the result of decreased RBC destruction, but it is also possible that spleen contraction after HDTBR contributed to this adaptation. Our data suggest that the decreased Hbmass 5 days following HDTBR resulted from decreased RBC production, not increased RBC destruction. Rapid decreases in haemoglobin mass (Hbmass) have been reported in healthy humans following spaceflight and descent from high altitude. It has been proposed that a selective increase in the destruction of young red blood cells (RBCs) mediates these decreases, but conclusive evidence demonstrating neocytolysis in humans is lacking. Based on the proposed triggers and time course of adaptation during spaceflight, we hypothesized that Hbmass would be reduced after 4 days of -6 deg head-down tilt bed rest (HDTBR) and that this would be associated with evidence for increased RBC destruction. We assessed Hbmass in seven healthy, recreationally active men before (PRE), 5 h after (POST) and 5 days after (POST5) 4 days of HDTBR. The concentration of erythropoietin decreased from 7.1 ± 1.8 mIU ml(-1) at PRE to 5.2 ± 2.8 mIU ml(-1) at POST (mean ± SD; P = 0.028). Contrary to our hypothesis, Hbmass was increased from 817 ± 135 g at PRE to 849 ± 141 g at POST (P = 0.014) before decreasing below PRE to 789 ± 139 g at POST5 (P = 0.027). From PRE to POST, the concentration of haptoglobin increased from 0.54 ± 0.32 to 0.68 ± 0.28 g l(-1) (P = 0.013) and the concentration of bilirubin decreased from 0.50 ± 0.24 to 0.32 ± 0.11 mg dl(-1) (P = 0.054), suggesting that decreased RBC destruction might have contributed to the increased Hbmass. However, it is possible that spleen contraction following HDTBR also played a role in the increase in Hbmass at POST, but as the transient increase in Hbmass was unexpected, we did not collect data that would provide direct evidence for or against spleen contraction. From PRE to POST5, the concentration of soluble transferrin receptor decreased from 20.7 ± 3.9 to 17.1 ± 3.3 nmol l(-1) (P = 0.018) but the concentrations of ferritin, haptoglobin and bilirubin were not significantly altered, suggesting that the decrease in Hbmass was mediated by decreased RBC production rather than increased RBC destruction. Peak oxygen uptake decreased by 0.31 ± 0.16 l min(-1) from PRE to POST (P = 2 × 10(-4) ) but was not significantly altered at POST5 compared with PRE. Overall, these findings indicate that 4 days of HDTBR does not increase RBC destruction and that re-examination of the time course and mechanisms of Hbmass alterations following short-term spaceflight and simulated microgravity is warranted.

Impaired hematopoietic progenitor cells in trauma hemorrhagic shock

Hemorrhagic shock (HS) is the major cause of death during trauma. Mortality due to HS is about 50%. Dysfunction of hematopoietic progenitor cells (HPCs) has been observed during severe trauma and HS. HS induces the elevation of cytokines, granulocyte-colony stimulating factor (G-CSF), peripheral blood HPCs, and circulating catecholamines, and decreases the expression of erythropoietin receptor connected with suppression of HPCs. Impaired HPCs may lead to persistent anemia and risk of susceptibility to infection, sepsis, and MOF. There is a need to reactivate impaired HPCs during trauma hemorrhagic shock.

Type I IFNs Act upon Hematopoietic Progenitors To Protect and Maintain Hematopoiesis during Pneumocystis Lung Infection in Mice

Although acquired bone marrow failure (BMF) is considered a T cell-mediated autoimmune disease, few studies have considered contributing roles of innate immune deviations following otherwise innocuous infections as a cause underlying the immune defects that lead to BMF. Type I IFN signaling plays an important role in protecting hematopoiesis during systemic stress responses to the opportunistic fungal pathogen Pneumocystis. During Pneumocystis lung infection, mice deficient in both lymphocytes and type I IFN receptor (IFrag(-/-)) develop rapidly progressing BMF associated with accelerated hematopoietic cell apoptosis. However, the communication pathway eliciting the induction of BMF in response to this strictly pulmonary infection has been unclear. We developed a conditional-null allele of Ifnar1 and used tissue-specific induction of the IFrag(-/-) state and found that, following Pneumocystis lung infection, type I IFNs act not only in the lung to prevent systemic immune deviations, but also within the progenitor compartment of the bone marrow to protect hematopoiesis. In addition, transfer of sterile-filtered serum from Pneumocystis-infected mice as well as i.p. injection of Pneumocystis into uninfected IFrag(-/-) mice induced BMF. Although specific cytokine deviations contribute to induction of BMF, immune-suppressive treatment of infected IFrag(-/-) mice ameliorated its progression but did not prevent loss of hematopoietic progenitor functions. This suggested that additional, noncytokine factors also target and impair progenitor functions; and interestingly, fungal β-glucans were also detected in serum. In conclusion, our data demonstrate that type 1 IFN signaling protects hematopoiesis within the bone marrow compartment from the damaging effects of proinflammatory cytokines elicited by Pneumocystis in the lung and possibly at extrapulmonary sites via circulating fungal components.

Transfusion strategies in hematologic and nonhematologic disease

Substantial progress has been made in our understanding of the risks and benefits of RBC transfusion through the performance of large clinical trials. More than 7000 patients have been enrolled in trials randomly allocating patients to higher transfusion thresholds (∼9-10 g/dL), referred to as liberal transfusion, or lower transfusion thresholds (∼7-8 g/dL), referred to as restrictive transfusion. The results of most of the trials suggest that a restrictive transfusion strategy is safe and, in some cases, superior to a liberal transfusion strategy. However, in patients with myocardial infarction, brain injury, stroke, or hematological disorders, more large trials are needed because preliminary evidence suggests that liberal transfusion might be beneficial or trials have not been performed at all.

Comparative transcriptomics of Atlantic Salmo salar, chum Oncorhynchus keta and pink salmon O. gorbuscha during infections with salmon lice Lepeophtheirus salmonis

Background

Salmon species vary in susceptibility to infections with the salmon louse (Lepeophtheirus salmonis). Comparing mechanisms underlying responses in susceptible and resistant species is important for estimating impacts of infections on wild salmon, selective breeding of farmed salmon, and expanding our knowledge of fish immune responses to ectoparasites. Herein we report three L. salmonis experimental infection trials of co-habited Atlantic Salmo salar, chum Oncorhynchus keta and pink salmon O. gorbuscha, profiling hematocrit, blood cortisol concentrations, and transcriptomic responses of the anterior kidney and skin to the infection.

Results

In all trials, infection densities (lice per host weight (g)) were consistently highest on chum salmon, followed by Atlantic salmon, and lowest in pink salmon. At 43 days post-exposure, all lice had developed to motile stages, and infection density was uniformly low among species. Hematocrit was reduced in infected Atlantic and chum salmon, and cortisol was elevated in infected chum salmon. Systemic transcriptomic responses were profiled in all species and large differences in response functions were identified between Atlantic and Pacific (chum and pink) salmon. Pink and chum salmon up-regulated acute phase response genes, including complement and coagulation components, and down-regulated antiviral immune genes. The pink salmon response involved the largest and most diverse iron sequestration and homeostasis mechanisms. Pattern recognition receptors were up-regulated in all species but the active components were often species-specific. C-type lectin domain family 4 member M and acidic mammalian chitinase were specifically up-regulated in the resistant pink salmon.

Conclusions

Experimental exposures consistently indicated increased susceptibility in chum and Atlantic salmon, and resistance in pink salmon, with differences in infection density occurring within the first three days of infection. Transcriptomic analysis suggested candidate resistance functions including local inflammation with cytokines, specific innate pattern recognition receptors, and iron homeostasis. Suppressed antiviral immunity in both susceptible and resistant species indicates the importance of future work investigating co-infections of viral pathogens and lice.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-200) contains supplementary material, which is available to authorized users.

Revisiting the association between altitude and mortality in dialysis patients

It was recently reported that residential altitude is inversely associated with all-cause mortality among incident dialysis patients; however, no adjustment was made for key case-mix and laboratory variables. We re-examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8-year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all-cause mortality. Using data from the US Geological Survey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by Cox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty-five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥ 6000 ft) had a lower all-cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86-0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all-cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders.

Iron status predicts malaria risk in Malawian preschool children

Introduction

Iron deficiency is highly prevalent in pre-school children in developing countries and an important health problem in sub-Saharan Africa. A debate exists on the possible protective effect of iron deficiency against malaria and other infections; yet consensus is lacking due to limited data. Recent studies have focused on the risks of iron supplementation but the effect of an individual's iron status on malaria risk remains unclear. Studies of iron status in areas with a high burden of infections often are exposed to bias. The aim of this study was to assess the predictive value of baseline iron status for malaria risk explicitly taking potential biases into account.

Methods and materials

We prospectively assessed the relationship between baseline iron deficiency (serum ferritin <30 µg/L) and malaria risk in a cohort of 727 Malawian preschool children during a year of follow-up. Data were analyzed using marginal structural Cox regression models and confounders were selected using causal graph theory. Sensitivity of results to bias resulting from misclassification of iron status by concurrent inflammation and to bias from unmeasured confounding were assessed using modern causal inference methods.

Results and Conclusions

The overall incidence of malaria parasitemia and clinical malaria was 1.9 (95% CI 1.8–2.0) and 0.7 (95% CI 0.6–0.8) events per person-year, respectively. Children with iron deficiency at baseline had a lower incidence of malaria parasitemia and clinical malaria during a year of follow-up; adjusted hazard ratio's 0.55 (95%-CI:0.41–0.74) and 0.49 (95%-CI:0.33–0.73), respectively. Our results suggest that iron deficiency protects against malaria parasitemia and clinical malaria in young children. Therefore the clinical importance of treating iron deficiency in a pre-school child should be weighed carefully against potential harms. In malaria endemic areas treatment of iron deficiency in children requires sustained prevention of malaria.

Adenosine-5'-triphosphate-adenosine-glutathione cross-linked hemoglobin as erythropoiesis-stimulating agent

An effective hemoglobin (Hb)-based blood substitute that acts as a physiological oxygen carrier and volume expander ought to stimulate erythropoiesis. A speedy replacement of blood loss with endogenous red blood cells should be an essential feature of any blood substitute product because of its relatively short circulatory retention time and high autoxidation rate. Erythropoiesis is a complex process controlled by oxygen and redox-regulated transcription factors and their target genes that can be affected by Hb physicochemical properties. Using an in vitro cellular model, we investigated the molecular mechanisms of erythropoietic action of unmodified tetrameric Hb (UHb) and Hb cross-linked with adenosine-5'-triphosphate (ATP), adenosine, and reduced glutathione (GSH). These effects were studied under normoxic and hypoxic conditions. Results indicate that these Hb solutions have different effects on stabilization and nuclear translocation of hypoxia-inducible factor (HIF)-1 alpha, induction of the erythropoietin (EPO) gene, activation of nuclear factor (NF)-kappa B, and expression of the anti-erythropoietic agents-tumor necrosis factor-alpha and transforming growth factor-beta 1. UHb suppresses erythropoiesis by increasing the cytoplasmic degradation of HIF-1 alpha and decreasing binding to the EPO gene while inducing NF-kappa B-dependent anti-erythropoietic genes. Cross-linked Hb accelerates erythropoiesis by downregulating NF-kappa B, stabilizing and facilitating HIF-1 alpha binding to the EPO gene, under both oxygen conditions. ATP and adenosine contribute to normoxic stabilization of HIF-1 and, with GSH, inhibit the NF-kappa B pathway that is involved in the suppression of erythroid-specific genes. Proper chemical/pharmacological modification is required to consider acellular Hb as an erythropoiesis-stimulating agent.

Renal anemia of inflammation: the name is self-explanatory

BACKGROUND

Anemia is inevitable as chronic kidney disease (CKD) advances. With the advent of erythropoietin-stimulating agents (ESAs), considerable improvement has been achieved in the management of anemia. However, some patients show a reduced response to ESAs.

METHODS

Many factors affect the response to ESA treatment. CKD is now considered as an inflammatory disorder and this understanding led to the recognition of the central role of inflammation in ESA resistance. Inflammation is related to untoward outcomes, including atherosclerosis and anemia, in the CKD population. Furthermore, recognition of deleterious effects of proinflammatory markers at different levels of erythropoiesis led to a change in the name of 'anemia of chronic disease' to anemia of inflammation.

RESULTS

The discovery of hepcidin as the major controller of iron metabolism in anemia of inflammation answered many questions regarding the interaction of erythropoietin, iron and bone marrow. Hepcidin production in the liver is driven by three major factors: inflammation, iron overload and anemia/hypoxia. Hepcidin levels are increased in patients with CKD due to the interaction of many factors; a comprehensive understanding of these pathways is thus critical in the effort to alleviate anemia of inflammation and ESA resistance.

CONCLUSION

In this review, we discussed the epidemiology, determinants and consequences of anemia of inflammation in CKD patients with special emphasis on the central role of hepcidin along with molecular pathways driving its production.

Improved method for assessing iron stores in the bone marrow

BACKGROUND

Bone marrow iron microscopy has been the "gold standard" method of assessing iron deficiency. However, the commonly used method of grading marrow iron remains highly subjective.

AIM

To improve the bone marrow grading method by developing a detailed protocol that assesses iron in fragments, in macrophages around fragments and in erythroblasts.

METHODS

A descriptive study of marrow aspirates of 303 children (aged 6-60 months) with severe anaemia and 22 controls (children undergoing elective surgery) was conducted at hospitals in southern Malawi (2002-04).

RESULTS

Using an intensive marrow iron grading method, 22% and 39% of cases and controls had deficient iron stores, and 40% and 46% had functional iron deficiency, respectively. Further evaluation of the iron status classification by the intensive method showed that functional iron deficiency was associated with significantly increased C-reactive protein concentrations (126.7 (85.6) mg/l), and iron stores deficiency with significantly increased soluble transferrin receptor concentrations (21.7 (12.5) mug/ml).

CONCLUSIONS

Iron assessment can be greatly improved by a more intense marrow examination. This provides a useful iron status classification which is of particular importance in areas where there is a high rate of inflammatory conditions.

Dysregulation of hepatic iron with aging: implications for heat stress-induced oxidative liver injury

Environmental heat stress is associated with an age-related increase in hepatic oxidative damage and an exaggerated state of oxidative stress. The purpose of this investigation was to evaluate the regulation of hepatic iron after heat stress. A secondary aim was to determine a potential role for iron in heat stress-induced liver injury. Hyperthermia-induced alterations in hepatic iron were evaluated in young (6 mo) and old (24 mo) Fischer 344 rats by exposing them to a two-heat stress protocol. Livers were harvested at several time points after the second heating and assayed for labile and nonheme iron. In the control condition, there was no difference in labile iron between age groups. Both labile iron and storage iron were not altered by hyperthermia in young rats, but both were increased immediately after heating in old rats. To evaluate a role for iron in liver injury, hepatic iron content was manipulated in young and old rats, and then both groups were exposed to heat stress. Iron administration to young rats significantly increased hepatic iron content and ferritin but did not affect markers of lipid peroxidation under control conditions or after heat stress. In old rats, iron chelation with deferoxamine prevented the increase in nonheme iron, labile iron, ferritin, and lipid peroxidation after heat stress. These results suggest that iron may play a role in hepatic injury after hyperthermia. Thus, dysregulation of iron may contribute to the gradual decline in cellular and physiological function that occurs with aging.

Gene expression profiles in mouse liver cells after exposure to different types of radiation

The liver is one of the target organs of radiation-induced cancers by internal exposures. In order to elucidate radiation-induced liver cancers including Thorotrast, we present a new approach to investigate in vivo effects of internal exposure to alpha-particles. Adopting boron neutron capture, we separately irradiated Kupffer cells and endothelial cells in mouse liver in vivo and analyzed the changes in gene transcriptions by an oligonucleotide microarray. Differential expression was defined as more than 3-fold for up-regulation and less than 1/3 for under-regulation, compared with non-irradiated controls. Of 6,050 genes examined, 68 showed differential expression compared with non-irradiated mice. Real-time polymerase chain reaction validated the results of the microarray analysis. Exposure to alpha-particles and gamma-rays produced different patterns of altered gene expression. Gene expression profiles revealed that the liver was in an inflammatory state characterized by up-regulation of positive acute phase protein genes, irrespective of the target cells exposed to radiation. In comparison with chemical and biological hepatotoxicants, inductions of Metallothionein 1 and Hemopexin, and suppressions of cytochrome P450s are characteristic of radiation exposure. Anti-inflammatory treatment could be helpful for the prevention and protection of radiation-induced hepatic injury.

Gamma-tocopherol and docosahexaenoic acid decrease inflammation in dialysis patients

OBJECTIVE

Increased cardiovascular risk in hemodialysis patients may be related to augmented oxidative stress and inflammation, for which no proven beneficial therapies are available.

STUDY DESIGN

We examined the effects of gamma tocopherol and docosahexaenoic acid (DHA) administration on inflammation and oxidative stress markers in hemodialysis patients in a randomized, double-blinded, placebo-controlled, clinical trial. Active treatment consisted of capsules containing gamma tocopherol (308 mg) and DHA (800 mg).

SETTING

Outpatient dialysis center.

PATIENTS

Seventy maintenance hemodialysis patients.

MAIN OUTCOME MEASURES

Plasma concentrations of interleukin-6 (IL-6) and protein carbonyl content were determined by enzyme-linked immunosorbant assay. C-reactive protein was measured by nephelometry. The F(2) isoprostanes were measured by gas chromatography-mass spectrometry. Erythrocyte DHA content was measured by gas chromatography.

RESULTS

Sixty-three patients were enrolled, and 57 completed the study. No serious adverse events were attributed to either active treatment or placebo. In the treatment group, but not in the placebo group, there were significant decreases in IL-6 (21.4 +/- 3.5 to 16.8 +/- 3.7 pg/mL), white blood cell (WBC) count (7.4 +/- 0.3 to 6.9 +/- 0.4 10(3)/microL), and neutrophil fraction of WBCs (4.8 +/- 0.3 to 4.4 +/- 0.3 10(3)/microL), at P < .05 for all. There were no significant changes in plasma concentrations of CRP, F(2) isoprostanes, or carbonyls in either group.

CONCLUSION

Thus, gamma tocopherol and DHA are well-tolerated and reduce selected biomarkers of inflammation in hemodialysis patients. Larger randomized, clinical trials will be required to determine if gamma tocopherol and DHA can reduce cardiovascular complications in hemodialysis patients.

Anaemia of cancer: an overview of mechanisms involved in its pathogenesis

Anaemia is a common complication in cancer patients. The decrease in haemoglobin is associated with an impaired quality of life, poorer response to therapy and worse prognosis. Numerous factors are involved in the physiopathology of cancer-related anaemia. Some factors such as bleeding, bone marrow infiltration, the effects of chemoradiotherapy and associated nutritional deficiencies are related to the disease itself. In addition, the interaction of the immune system with iron metabolism and erythropoiesis has been shown to be an important factor in the development of anaemia in cancer patients and can be seen in the action of several cytokines on different iron-homeostasis and erythrocyte-cell-production pathways. Some inhibitory cytokines, such as tumour necrosis factor-alpha and interleukin-1, act on the suppression of erythroid precursor cells and erythropoietic production and response; others, such as interleukins 1 and 6 and hepcidin, impair iron metabolism, causing iron to be diverted from erythropoiesis and retained within the reticuloendothelial system. The main mechanisms involved in the development of cancer-related anaemia are discussed in this review.

Quotidian hemodialysis and inflammation associated with chronic kidney disease

The mortality rate of chronic dialysis patients in the United States is 24% per year per the 2006 United States Renal Data System. Although there have been marked improvements in dialysis technology, cardiovascular disease is the principal cause of mortality in end-stage renal disease patients. Inflammation and left ventricular hypertrophy both contribute to atherosclerosis. Hemodialysis 3 times a week is the most commonly used form of dialysis in the United States. The multicenter hemodialysis (HEMO) study hypothesized that an increase in dialysis dose and use of high-flux membranes would improve mortality and decrease morbidity. This study failed to show decreases in mortality. In other studies, however, there appears to be improved morbidity with more frequent dialysis including daily nocturnal hemodialysis and short-daily hemodialysis. The more frequent dialysis may have some beneficial effect on the inflammatory process that occurs in end-stage renal disease.

TGF-beta combined with M-CSF and IL-4 induces generation of immune inhibitory cord blood dendritic cells capable of enhancing cytokine-induced ex vivo expansion of myeloid progenitors

Tolerogenic dendritic cells (DCs) may be valuable in transplantation for silencing immune reaction. Macrophage colony-stimulating factor (M-CSF)/IL-4 induces differentiation of cord blood (CB) monocytes into DCs (M-DCs) with tolerogenic phenotype/function. We assessed whether factors produced by tolerogenic DCs could modulate hematopoiesis. TGF-beta1 added to CB M-DC cultures induced bona fide DC morphology (TGF-M-DCs), similar to that of DCs generated with TGF-beta and granulocyte-macrophage colony-stimulating factor (GM-CSF)/IL-4 (TGF-GM-DCs). Of conditioned media (CM) produced from TGF-M-DCs, TGF-GM-DCs, M-DCs, and GM-DCs, TGF-M-DC CM was the only one that enhanced SCF, Flt3 ligand, and TPO expansion of myeloid progenitor cells ex vivo. This effect was blocked by neutralizing anti-M-CSF Ab, but protein analysis of CM suggested that M-CSF alone was not manifesting enhanced expansion of myeloid progenitors. LPS-stimulated TGF-M-DCs induced T-cell tolerance/anergy as effectively as M-DCs. TGF-M-DCs secreted significantly lower concentrations of progenitor cell inhibitory cytokines and were less potent in activating T cells than TGF-GM-DCs. Functional differences between TGF-M-DCs and TGF-GM-DCs included enhanced responses to LPS-induced ERK, JNK, and P38 activation in TGF-M-DCs and their immune suppressive-skewed cytokine release profiles. TGF-M-DCs appear unique among culture-generated DCs in their capability for silencing immunity while promoting expansion of myeloid progenitors, events that may be of therapeutic value.

Erythropoiesis in multiply injured patients

Posttraumatic anemia in multiply injured patients is caused by hemorrhage, reduced red blood cell survival, and impaired erythropoiesis. Trauma-induced hyperinflammation causes impaired bone-marrow function by means of blunted erythropoietin (EPO) response, reduced iron availability, suppression and egress of erythroid progenitor cells. To treat posttraumatic anemia in severely injured patients, symptomatic therapy by blood transfusion is not sufficient. Furthermore, EPO, iron, and the use of red cell substitutes should be considered. The posttraumatic systemic inflammatory response syndrome (SIRS) induces posttraumatic anemia. Thus, a worsening of SIRS by a "second-hit" through blood transfusion ought to be avoided.

Enhancement of natural killer cells and increased survival of aging mice fed daily Echinacea root extract from youth

In spite of Echinacea-based products being among the best-selling herbs in the world to date, to allay assorted ailments, the debate is still on-going with respect to the efficacy of ingesting the herb intermittently, continuously, or only at the beginning of an affliction. We sought, therefore, to find out if mice, receiving dietary Echinacea daily, throughout life, from youth until late middle-age, demonstrated any longevity/survival differences, and/or any differences in their various populations of immune/ hemopoietic cells. Sustained and/or high levels of these cells are crucial for longevity. Some mice were maintained on a regular chow diet to which was added Echinacea purpurea daily (2 mg/mouse), from puberty (7 week) until just beyond 13 months of age (late middle-age in mice). Control mice, identically housed and maintained, received identical chow without the herb. Mice consuming untreated diet had a 79% survival by 10 months of age, while those consuming Echinacea daily in the diet were still 100% alive by 10 months. At approximately 13 months of age, mice consuming untreated diet had a 46% survival rate while those consuming Echinacea, were 74% alive at this time. Moreover, the key immune cells, acting as the first line of defense against developing neoplasms in mice and humans, i.e., natural killer (NK) cells, were significantly elevated in absolute number both in their bone marrow production site, as well as in the major organ to which they traffic and function, i.e., the spleen. The cells of the myeloid/granulocyte lineages remained steadfastly at control levels in both the bone marrow and spleen in Echinacea-consuming mice. Thus, it appears that regular intake of Echinacea may indeed be beneficial/prophylactic, if only for the reason that it maintains in an elevated state, NK cells, prime elements in immunosurveillance against spontaneous-developing tumors, a phenomenon which increases in frequency with progressive aging.

Association between nucleated red blood cells in blood and the levels of erythropoietin, interleukin 3, interleukin 6, and interleukin 12p70

The appearance of nucleated red blood cells (NRBC) in the circulation is associated with a variety of severe diseases, and indicates a relatively poor prognosis. Whether a malfunction of the bone marrow leads to this phenomenon is as unknown as the possible role that cytokines could play in this process. We analyzed erythropoietin, interleukin (IL)-3, IL-6, and IL-12p70 in the blood of 301 patients with circulating NRBCs. Two hundred fifty NRBC-negative patients served as controls. Multiple logistic regression revealed a significant association between the appearance of NRBCs in the blood and erythropoietin (odds ratio, 1.017; 95% confidence limits, 1.007-1.027; P < 0.001), IL-3 (odds ratio, 1.293; 95% confidence limits, 1.180-1.417; P < 0.001), IL-6 (odds ratio, 1.138; 95% confidence limits, 1.016-1.275; P < 0.05), and age (odds ratio, 1.019; 95% confidence limits, 1.009-1.030; P < 0.001), respectively. Gender and IL-12p70 were not significantly associated with the appearance of NRBC in the blood. To estimate the RBC production in the bone marrow, the increase in the reticulocyte concentration in blood was measured. The reticulocyte concentration in NRBC-positive patients was 69 +/- 2/nL, which was significantly higher than in NRBC-negative patients (60 +/- 2/nL; P < 0.01). Taken together, NRBC could be a marker that sums up hypoxic and inflammatory injuries. Thus, generally, the appearance of NRBC in blood is a valid parameter to identify patients at high mortal risk. Moreover, the increased number of reticulocytes in the blood of NRBC-positive patients may indicate that the appearance of NRBC is not associated with disturbed bone marrow function as far as the erythropoiesis is concerned.

Quotidian nocturnal hemodialysis improves cytokine profile and enhances erythropoietin responsiveness

Inflammation is implicated in the pathogenesis of erythropoietin (EPO) resistance in patients with end-stage renal disease. Interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha are suggested to suppress erythropoiesis in uremia. Insulin like growth factor (IGF)-1 has been proposed to stimulate erythropoiesis. Nocturnal hemodialysis (NHD) has been demonstrated to improve anemia management with enhanced EPO responsiveness without altering survival of red blood cells. We tested the hypothesis that augmentation of uremia clearance by NHD results in a reduction of proinflammatory cytokine levels, thereby enhancing EPO responsiveness. Using a cross-sectional study design, 14 prevalent patients on NHD and 14 patients on conventional hemodialysis (CHD) matched for age and comorbidities and controlled for hemoglobin concentrations and iron status were studied. Outcome variables included EPO requirement and plasma levels of EPO, parathyroid hormone, C reactive protein, IL-6, TNF-alpha, and IGF-1. The primary outcome was to determine the between group differences in (1) cytokine profile and (2) EPO requirement. The secondary outcome was to examine the potential correlation between cytokine levels and EPO requirement. There were no significant differences in patient characteristics, comorbidities, hemoglobin, iron indices, and parathyroid hormone levels between the two cohorts. EPO requirement was significantly lower in the NHD cohort [90.5 +/- 22.1 U/kg/ week (NHD) vs. 167.2 +/- 25.4 U/kg/week (CHD), p = 0.04]. Plasma IL-6 levels were lower in the NHD cohort [3.9 +/- 0.7 pg/ml (NHD) vs. 6.5 +/- 0.8 pg/ml (CHD), p = 0.04]. C reactive protein tended to decrease [4.59 +/- 1.34 (NHD) vs. 8.43 +/- 1.83 mg/L (CHD), p = 0.14]. TNF-alpha, and IGF-1 levels did not differ between the two groups. Direct associations were found between EPO requirement and C reactive protein levels (R = 0.62, p = 0.001), and IL-6 levels (R = 0.57, p = 0.002). Augmentation of uremic clearance by NHD improves EPO responsiveness in end-stage renal disease. A possible mechanism for this improvement is through better control of inflammation, as manifested by lowering of plasma IL-6 levels. Further studies are required to clarify the mechanisms by which NHD decreases inflammation.

Anemia of chronic disease: pathophysiology and laboratory diagnosis

Classic iron deficiency (ID) does not represent a challenge for the laboratory and physicians. The anemia that accompanies infection, inflammation, and cancer, commonly termed anemia of chronic disease (ACD), features apparently normal or increased iron stores. However, 20% of these patients have iron-restricted erythropoiesis (functional ID), an imbalance between the iron requirements of the erythroid marrow and the actual iron supply. Functional ID leads to a reduction in red cell hemoglobiniza-tion, causing hypochromic microcytic anemia. The diagnosis of functional ID in real time is based on measuring the hemoglobin content of reticulocytes. An examination of the biochemical markers of iron metabolism demonstrates weaknesses in the diagnosis of functional ID. We developed a diagnostic plot for the assessment of iron status in ACD and the detection of advancing ID in patients with ID, ACD, and the combined state of functional ID and ACD. The plot indicates the correlation between a marker of the iron supply for erythropoiesis (ie, the ratio of the soluble transferrin receptor value to the logarithm of the ferritin value) and the reticulocyte hemoglobin content and functions as a marker of iron demand. The diagnostic plot shows good selectivity for assessing the iron status of disease-specific anemias such as classic ID, end-stage renal failure, cancer-related anemia, and the anemia of infection and inflammation. The therapeutic implications of the diagnostic plot are to differentiate patients who should be administered oral iron supplements, recombinant human erythropoietin (r-HuEPO), or a combination of r-HuEPO and iron. The response of erythropoiesis to r-HuEPO depends on the iron supply and the proliferation of erythropoiesis. The lack of an increase or a decrease in reticulocyte hemoglobin levels indicates a nonresponder to r-HuEPO or functional ID.

An acute inflammatory response alters bone homeostasis, body composition, and the humoral immune response of broiler chickens

To quantify the effects of an acute phase response in broilers, chicks were injected with 1 mg/kg Escherichia coli lipopolysaccharide (LPS) at 15 and 23 d. Lipopolysaccharide injection increased feed/gain (P = 0.03), increased liver weight (P = 0.09), and decreased tibia calcium (P = 0.05) and breaking strength (P < 0.04) by d 28. In a second experiment, 3 d postinjection of chicks at d 31, LPS decreased BW (P < 0.01), breast weight (P = 0.08), and tibia breaking strength (P = 0.05), and increased liver weight (P < 0.01), mortality (P = 0.05), and titers to bronchitis and Mycoplasma gallisepticum that were induced by vaccination at hatch or by field exposure, respectively (P = 0.04). For experiment 3, chicks were challenged with LPS at 23d and 27d. Lipopolysaccharide-injected chicks had decreased BW (P = 0.06), feed consumption (P = 0.05), tibia weight (P< 0.01), and breaking strength (P < 0.01), and increased feed/gain (P < 0.01), liver weight (P < 0.01), and plasma ionized calcium level (P = 0.08). For experiment 4, chicks were injected with 0, 0.33, 0.66, 1.00, or 4.25 mg of LPS/kg of BW. There was an inverse relationship between LPS level and BW or bone breaking strength. Experiment 5 compared 4 broiler strains. Strain x LPS interactions were found for bone breaking strength (P = 0.01). Mortality before LPS challenge was inversely correlated to liver weight (r2 = 0.95, P = 0.02) and bone breaking strength (r2 = 0.99, P = 0.01) only after an LPS challenge.

Erythropoeitin dose variation in different facilities in different countries and its relationship to drug resistance

BACKGROUND

The correction of anemia using erythropoeitin (EPO) is accorded high priority in the management of patients undergoing hemodialysis (HD). Target hemoglobin (Hb) levels have been established in many countries. Following an observation that the mean facility EPO dose in a chain of facilities in the United States varied by more than two-fold, an examination of the practice of anemia correction in other settings was carried out.

METHODS

We reviewed demographic and laboratory parameters in prevalent HD patients in 50 United States facilities and in a single HD facility in Vicenza, Italy. The mean EPO dose profile of the United States facilities was compared with the profiles in 10 facilities in the eastern United Kingdom (UKER) and in 20 facilities reporting to the United Kingdom Renal Registry (UKRR). Analysis of the factors that correlate with EPO resistance was carried out using the United States and Italian data.

RESULTS

The average EPO doses, by facility, in the 51 United States, the 10 UKER, and the 19 UKRR facilities were 19,569, 8,416, and 7,992 international units per week (IU/wk), respectively. While examination of the UKRR revealed a similar degree of inter-facility variation (2.6-fold), much larger doses of EPO were being administered in the United States patients, particularly in the low Hb group. Multivariate analysis of the United States data suggested that factors related to inflammation, including low albumin, the use of tunneled catheters for vascular access, and low protein catabolic rate (enPCR) correlated with low Hb and relative EPO resistance.

CONCLUSION

Despite similar guidelines for anemia management, significant differences in practice are observed. While there seems to be a reluctance to administer large EPO doses to individual patients in Europe, this does not seem to apply in the United States, where more EPO is given. EPO resistance seems relative rather than absolute in many patients, allowing some to respond to the higher doses.

Soluble Fas: a novel marker of inflammation in uremia

BACKGROUND

Inflammation has been associated with atherosclerotic cardiovascular disease (CVD) and anemia in patients with end-stage renal disease (ESRD). Recent studies have shown that serum levels of soluble Fas (sFas), an antiapoptotic and proinflammatory molecule, are elevated in patients with cardiac disease and patients with ESRD. We therefore sought to investigate serum levels of sFas in uremic patients and its correlation with known markers of inflammation, anemia and CVD.

METHODS

The study included 25 ESRD patients (14 on hemodialysis, 11 on CAPD), 27 patients with chronic kidney disease (CKD; creatinine clearance <50 ml/min/1.73 m2), and 14 normal control subjects. We measured serum levels of sFas, C-reactive protein (CRP), and albumin. We also investigated the association of serum sFas levels with the presence of CVD and with erythropoietin (EPO) dosage.

RESULTS

Levels of sFas were elevated in CKD and ESRD patients compared to controls. sFas levels correlated negatively with creatinine clearance. In the dialysis patients, we observed that sFas levels were higher among those with CVD. Serum levels of sFas correlated with serum levels of CRP (r=0.31; P=0.03), serum levels of albumin (r=-0.35, P=0.02), and EPO dosage (r=0.51; P=0.009).

CONCLUSION

These results suggest that sFas may be a marker of inflammation in CKD and ESRD patients.

Relevance of C-reactive protein levels in peritoneal dialysis patients

BACKGROUND

C-reactive protein (CRP) levels are increased in 30 to 50% of dialysis patients and predict cardiovascular morbidity and mortality. It is usually considered that raised CRP levels reflect underlying atherosclerosis. However, many patients may have clinically apparent cardiovascular disease without raised CRP levels. This study was designed to assess both the risk factors for high CRP levels and the usefulness of the test as a marker of clinically apparent coronary artery disease (CAD), peripheral vascular disease (PVD) and the presence of ongoing infections/inflammatory disorders (INF-INFL) in peritoneal dialysis patients.

METHODS

A chart review of 190 prevalent peritoneal dialysis patients was performed. CRP, albumin, ferritin, erythropoietin (EPO) dose and resistance, Kt/V, and residual renal function values were obtained and a history or presence of cardiovascular disease (CAD, PVD) and presence of INF-INFL recorded. Data were analyzed by Chi-square, Spearman correlation and logistic regression.

RESULTS

A total of 31% of patients had a raised CRP. INF-INFL was highly predictive of raised CRP levels (OR 16.97; 95% CI 5.41 to 53.14, P=0.000), whereas CAD and PVD either singly or in combination had no such association. The sensitivity/specificity for CRP as a test for INF-INFL was 83/77%. For CAD and PVD, the sensitivities were less than 40% and specificities 70%. Increased CRP values were more common in females but not in diabetics. Weak linear correlations existed between CRP levels and albumin, ferritin and residual renal function (r=-0.212, 0.228 and -0.163 respectively, P < 0.02). By regression analysis, INF-INFL predicted high CRP levels, but CAD and PVD did not. The majority of patients (57%) with high CRP had no identifiable cause; 40% of these patients had subsequent or previous normal CRP values. High transport status predicted high CRP levels (OR 7.28; 95% CI 1.417 to 37.36, P=0.006).

CONCLUSIONS

The majority of elevated CRP levels in peritoneal dialysis patients occur without an obvious cause. Clinically apparent cardiovascular disease does not predict high CRP levels. CRP levels vary over time in the same patient, from normal to high or vice versa, for no obvious reason. Sources of inflammation other than CAD, PVD and clinically obvious INF-INFL in peritoneal dialysis patients remain to be identified.

Acute phase proteins, body temperature and urinary melatonin under the influence of bright and dim light intensities during the daytime

Concentrations of five acute phase proteins: C-reactive protein (CRP), alpha 1-antichymotrypsin (ACT), transferin (Tf), alpha 2-macroglobulin (alpha 2-M) and haptoglobin (Hp) as well as glycosylation profiles of alpha 1-antichymotrypsin (ACT) were studied in sera samples with 7 healthy volunteers under the influence of two different light intensities during the daytime dim (100 lx) and bright (3000 lx) light. Concentration of transferin (negative proteins) under the influence of bright light during the daytime decreased significantly. Other proteins have the tendency to increase (positive proteins) under the influence of daytime bright light. The microheterogeneity of ACT did not change under the influence of different light intensities. Melatonin and rectal temperature were also measured simultaneously. Rectal temperature decreased to be lower during the first half of the night and urinary melatonin secretion rate increased to be higher during the night when the subjects spent time under the bright light during the day. Thus, it is concluded that the diurnal bright light exposure may activate some parameters of acute phase proteins, increase nocturnal melatonin secretion and accelerate a fall of rectal temperature during first half period of night sleep.

Acute-phase response predicts erythropoietin resistance in hemodialysis and peritoneal dialysis patients

We defined erythropoietin (EPO) resistance by the ratio of the weekly EPO dose to hematocrit (Hct), yielding a continuously distributed variable (EPO/Hct). EPO resistance is usually attributed to iron or vitamin deficiency, hyperparathyroidism, aluminum toxicity, or inflammation. Activation of the acute-phase response, assessed by the level of the acute-phase C-reactive protein (CRP), correlates strongly with hypoalbuminemia and mortality in both hemodialysis (HD) and peritoneal dialysis (PD) patients. In this cross-sectional study of 92 HD and 36 PD patients, we examined the contribution of parathyroid hormone (PTH) levels, iron indices, aluminum levels, nutritional parameters (normalized protein catabolic rate [PCRn]), dialysis adequacy (Kt/V), and CRP to EPO/Hct. Albumin level serves as a measure of both nutrition and inflammation and was used as another independent variable. Serum albumin level (deltaR2 = 0.129; P < 0.001) and age (deltaR2 = 0.040; P = 0.040) were the best predictors of EPO/Hct in HD patients, and serum albumin (deltaR2 = 0.205; P = 0.002) and ferritin levels (deltaR2 = 0.132; P = 0.015) in PD patients. When albumin was excluded from the analysis, the best predictors of EPO/Hct were CRP (deltaR2 = 0.105; P = 0.003) and ferritin levels (deltaR2 = 0.051; P = 0.023) in HD patients and CRP level (deltaR2 = 0.141; P = 0.024) in PD patients. When both albumin and CRP were excluded from analysis in HD patients, low transferrin levels predicted high EPO/Hct (deltaR2 = 0.070; P = 0.011). EPO/Hct was independent of PTH and aluminum levels, PCRn, and Kt/V. High EPO/Hct occurred in the context of high ferritin and low transferrin levels, the pattern expected in the acute-phase response, not in iron deficiency. In well-dialyzed patients who were iron replete, the acute-phase response was the most important predictor of EPO resistance.

Angiogenin is regulated in vivo as an acute phase protein

Angiogenin (Ang), a potent mediator of neovascularization, is secreted by and is critical for the growth of human tumor cells in experimental animals. However, control mechanisms that regulate its expression under normal physiological conditions have not been described. We have determined previously that Ang is present in normal human serum and that its concentration, normally falling within a narrow range, can vary widely in hospitalized patients. This observation, plus a report that Ang is synthesized in the adult liver, led us to investigate whether it can be regulated as an acute phase protein (APP). Ang concentration in the serum of mice placed into the acute phase by injection with 3% thioglycollate do indeed increase transiently as is typical for APPs. Moreover, a liver-specific rise and subsequent fall in Ang mRNA transcripts also follows entrance into acute inflammation. We conclude that Ang can be regulated in vivo in a manner that is characteristic of an APP and, therefore, may contribute to the angiogenic component of tissue repair that accompanies host response to inflammation and trauma. To our knowledge, this is the first demonstration that a well-characterized angiogenic mediator can be regulated as an APP.