Temporary impairment of reticulocyte haemoglobin content in subjects with community-acquired pneumonia

Plasma Levels of Hepcidin and Reticulocyte Haemoglobin during Septic Shock

Septic shock, a serious consequence of disseminated infection that has a high mortality, is due to a dysregulated, severe immune response triggered by the infection. Acute phase reactants play key roles in sepsis, for example, hepcidin regulating iron metabolism. Reticulocyte haemoglobin (Ret-He) depends on available iron in blood, indirectly regulated by hepcidin. This study aimed at exploring rapid changes in hepcidin and Ret-He in patients with septic shock receiving adequate antibiotic treatment. Fifteen patients, included within an hour of admission to the intensive care unit, were evaluated by microbiological tests and cultures, Sequential Organ Failure Assessment score, and plasma levels of hepcidin, Ret-He, heparin-binding protein (HBP), leucocytes, C-reactive protein, procalcitonin (PCT), and lactate. Samples were taken every morning for 7 consecutive days. Maximal levels of hepcidin (median 61 nmol/L; reference 1-12 nmol/L) were seen at the time of inclusion, then declining steadily similar to PCT and lactate levels. Ret-He values decreased transiently in response to increased hepcidin, normalization occurred at 96 h upon decrease of hepcidin levels. Maximal levels of HBP were noted 24 h after inclusion. In conclusion, hepcidin promptly declined within the first 24 h in patients with septic shock receiving adequate antibiotic treatment in contrast to Ret-He and HBP.

Footprints of Sepsis Framed Within Community Acquired Pneumonia in the Blood Transcriptome

We analyzed the blood transcriptome of sepsis framed within community-acquired pneumonia (CAP) and characterized its molecular and cellular heterogeneity in terms of functional modules of co-regulated genes with impact for the underlying pathophysiological mechanisms. Our results showed that CAP severity is associated with immune suppression owing to T-cell exhaustion and HLA and chemokine receptor deactivation, endotoxin tolerance, macrophage polarization, and metabolic conversion from oxidative phosphorylation to glycolysis. We also found footprints of host's response to viruses and bacteria, altered levels of mRNA from erythrocytes and platelets indicating coagulopathy that parallel severity of sepsis and survival. Finally, our data demonstrated chromatin re-modeling associated with extensive transcriptional deregulation of chromatin modifying enzymes, which suggests the extensive changes of DNA methylation with potential impact for marker selection and functional characterization. Based on the molecular footprints identified, we propose a novel stratification of CAP cases into six groups differing in the transcriptomic scores of CAP severity, interferon response, and erythrocyte mRNA expression with impact for prognosis. Our analysis increases the resolution of transcriptomic footprints of CAP and reveals opportunities for selecting sets of transcriptomic markers with impact for translation of omics research in terms of patient stratification schemes and sets of signature genes.

Biomarkers of hypochromia: the contemporary assessment of iron status and erythropoiesis

Iron status is the result of the balance between the rate of erythropoiesis and the amount of the iron stores. Direct consequence of an imbalance between the erythroid marrow iron requirements and the actual supply is a reduction of red cell hemoglobin content, which causes hypochromic mature red cells and reticulocytes. The diagnosis of iron deficiency is particularly challenging in patients with acute or chronic inflammatory conditions because most of the biochemical markers for iron metabolism (serum ferritin and transferrin ) are affected by acute phase reaction. For these reasons, interest has been generated in the use of erythrocyte and reticulocyte parameters, available on the modern hematology analyzers. Reported during blood analysis routinely performed on the instrument, these parameters can assist in early detection of clinical conditions (iron deficiency, absolute, or functional; ineffective erythropoiesis, including iron restricted or thalassemia), without additional cost. Technological progress has meant that in recent years modern analyzers report new parameters that provide further information from the traditional count. Nevertheless these new parameters are exclusive of each manufacturer, and they are patented. This is an update of these new laboratory test biomarkers of hypochromia reported by different manufactures, their meaning, and clinical utility on daily practice.

Transient impairment of reticulocyte hemoglobin content and hepcidin-25 induction in patients with community-acquired pneumonia

INTRODUCTION

Patients with community-acquired pneumonia (CAP) often exhibit a declining hemoglobin (Hb) concentration. During inflammation pro-inflammatory cytokines and cells of the reticuloendothelial system induce disturbances in iron homeostasis. In this study inflammation markers and hepcidin-25 concentrations were monitored together with short-term alterations in reticulocyte hemoglobinization (RET-He).

METHODS

A total of 25 patients with CAP participated in the study. The assay for serum hepcidin-25 is based on a combination of weak cation exchange chromatography and time-of-flight mass spectrometry.

RESULTS

At hospital admission serum hepcidin-25 concentrations (14.6 ± 6.9 nMol/L, mean ± SD) were established in the upper level of the reference range (0.5-13.9 nMol/L). Results for C-reactive protein (CRP) and Interleukin-6 (IL-6) were obviously increased compared to the reference ranges. From admission until day 14 hepcidin-25, CRP and IL-6 steadily decreased towards the reference ranges. Hb concentrations declined from admission until day 4 from 8.1 ± 1.0 mMol/L to 7.4 ± 0.9 mMol/L. At admission Ret-He results were within the lower region of the reference range (1900-2300aMol) and results demonstrated a decline during admission from 1931 ± 241 aMol until 1845 ± 199 aMol (NS) at day 4. From a minimum Ret-He value at day 4 results increased towards 2129 ± 136 aMol at day14.

CONCLUSION

A transient increase of cytokine-stimulated serum hepcidin-25 in combination with a temporary decrease of Hb and Ret-He is demonstrated in patients with CAP. Our results support the hypothesis that hepcidin-25 induces transient impairment of reticulocyte hemoglobin content (Ret-He).