Hepcidin and Ferritin: Important Mediators in Inflammation Associated Anemia in Systemic Lupus Erythematosus Patients

Serum hepcidin and ferritin as markers of iron deficiency in premature infants born at less than 32 weeks of gestation: prospective observational study

BACKGROUND

Preterm infants born at less than 32 weeks of gestation are at higher risk of low total iron stores (iron deficiency). Serum ferritin is used as a valid total iron stores and iron deficiency biomarker, usually as a combination of ferritin and red blood cell counts.

METHODS

Serum hepcidin and ferritin values and red blood cell counts were obtained from 37 of 40 included premature infants born at less than 32 weeks of gestation at risk of iron deficiency. The first sample was obtained in the first week of life, and the second at transfer from the Neonatal intensive care unit to the maternity ward, when serum ferritin level below 25 µg/L has been defined as very low total iron stores (iron deficiency).

RESULTS

Ferritin median levels decreased from a median value of 152 µg/L at the first measurement to 54 µg/L at the second measurement. Hepcidin median levels also decreased from 30.1 µg/L to 2.1 µg/L. We found a positive and statistically significant correlation between levels of ferritin and hepcidin at both measurements (r=0.57; P<0.001 and r=0.72; P<0.001, respectively). Compared to serum hepcidin, ferritin at the first measurement has not statistically significant higher power in predicting children with iron deficiency before discharge from the hospital.

CONCLUSIONS

We found a correlation between ferritin and hepcidin levels. Nevertheless, hepcidin does not have a worse power in predicting children with iron deficiency compared to ferritin.

Functional consequence of Iron dyshomeostasis and ferroptosis in systemic lupus erythematosus and lupus nephritis

Systemic lupus erythematosus (SLE) and its renal manifestation Lupus nephritis (LN) are characterized by a dysregulated immune system, autoantibodies, and injury to the renal parenchyma. Iron accumulation and ferroptosis in the immune effectors and renal tubules are recently identified pathological features in SLE and LN. Ferroptosis is an iron dependent non-apoptotic form of regulated cell death and ferroptosis inhibitors have improved disease outcomes in murine models of SLE, identifying it as a novel druggable target. In this review, we discuss novel mechanisms by which iron accumulation and ferroptosis perpetuate immune cell mediated pathology in SLE/LN. We highlight intra-renal dysregulation of iron metabolism and ferroptosis as an underlying pathogenic mechanism of renal tubular injury. The basic concepts of iron biology and ferroptosis are also discussed to expose the links between iron, cell metabolism and ferroptosis, that identify intracellular pro-ferroptotic enzymes and their protein conjugates as potential targets to improve SLE/LN outcomes.

B-1 derived anti-Thy-1 B cells in old aged mice develop lymphoma/leukemia with high expression of CD11b and Hamp2 that different from TCL1 transgenic mice

Human old aged unmutated chronic lymphocytic leukemia U-CLL are the TCL1+ZAP70+CD5+ B cells. Since CD5 makes the BCR signaling tolerance, ZAP70 increased in U-CLL not only TCL1+ alone. In mice, TCL1 (TCL1A) is the negative from neonate to old aged, as TC-. VH8-12/Vk21-5 is the anti-thymocyte/Thy-1 autoreactive ATA B cell. When ATA μκTg generation in mice, ATA B cells are the neonate generated CD5+ B cells in B-1, and in the middle age, CD5+ can be down or continuously CD5+, then, old aged CLL/lymphoma generation with increased CD11b in TC-ZAP70-CD5- or TC-ZAP70+CD5+. In this old aged TC-ATA B microarray analysis showed most similar to human CLL and U-CLL, and TC-ZAP70+CD5+ showed certain higher present as U-CLL. Original neonate ATA B cells showed with several genes down or further increase in old aged tumor, and old aged T-bet+CD11c+, CTNNB1hi, HMGBhi, CXCR4hi, DPP4hi and decreased miR181b. These old aged increased genes and down miR181b are similar to human CLL. Also, in old age ATA B cell tumor, high CD38++CD44++, increased Ki67+ AID+, and decreased CD180- miR15Olow are similar to U-CLL. In this old aged ATA B, increased TLR7,9 and Wnt10b. TC+Tg generated with ATAμκTg mice occurred middle age tumor as TC+ZAP70-CD5+ or TC+ZAP70+CD5+, with high NF-kB1, TLR4,6 and Wnt5b,6 without increased CD11b. Since neonatal state to age with TC+Tg continuously, middle age CLL/lymphoma generation is not similar to old aged generated, however, some increased in TC+ZAP70+ are similar to the old age TC- ATA B tumor. Then, TC- ATA B old age tumor showed some difference to human CLL. ATA B cells showed CD11b+CD22++, CD24 down, and hepcidin Hamp2++ with iron down. This mouse V8-12 similar to human V2-5, and V2-5 showed several cancers with macrophages/neutrophils generated hepcidin+ ironlow or some showed hepcidin- iron+ with tumor, and mouse V8-12 with different Vk19-17 generate MZ B cells strongly increased macrophage++ in old aged and generated intestine/colon tumor. Conclusion, neonate generated TC-ATA B1 cells in old aged tumor generation are CD11b+ in the leukemia CLL together with lymphoma cancer with hepcidin-related Hamp2++ in B-1 cell generation to control iron.

Elevated Serum Levels of Soluble Transferrin Receptor Are Associated with an Increased Risk of Cardiovascular, Pulmonary, and Hematological Manifestations and a Decreased Risk of Neuropsychiatric Manifestations in Systemic Lupus Erythematosus Patients

The aim of this study was to analyze the relationship between the serum levels of soluble transferrin receptor (sTfR) and interleukin 4 (IL-4), and the disease activity and organ manifestations in SLE patients. We studied 200 SLE patients and 50 controls. We analyzed disease activity, organ involvement, serum sTfR, IL-4 and interleukin-6 (IL-6) levels, and antinuclear and antiphospholipid antibody profiles. The median serum levels of sTfR (p > 0.000001) and IL-4 (p < 0.00001) were higher in the study group than in the controls. SLE patients, compared to the controls, had significantly lower HGB levels (p < 0.0001), a lower iron concentration (p = 0.008), a lower value of total iron-binding capacity (TIBC) (p = 0.03), and lower counts of RBC (p = 0.004), HCT (p = 0.0004), PLT (p = 0.04), neutrophil (p = 0.04), and lymphocyte (p < 0.0001). Serum sTfR levels were negatively correlated with lymphocyte (p = 0.0005), HGB (p = 0.0001) and HCT (p = 0.008), and positively correlated with IL-4 (p = 0.01). Elevated serum sTfR > 2.14 mg/dL was associated with an increased risk of myocardial infarction (OR: 10.6 95 CI 2.71-464.78; p = 0.001), ischemic heart disease (OR: 3.25 95 CI 1.02-10.40; p = 0.04), lung manifestations (OR: 4.48 95 CI 1.44-13.94; p = 0.01), and hematological manifestations (OR: 2.07 95 CI 1.13-3.79; p = 0.01), and with a reduced risk of neuropsychiatric manifestations (OR: 0.42 95 CI 0.22-0.80; p = 0.008). Serum IL-4 was negatively correlated with CRP (p = 0.003), and elevated serum IL-4 levels > 0.17 mg/L were associated with a reduced risk of mucocutaneous manifestations (OR: 0.48 95 CI 0.26-0.90; p = 0.02). In SLE patients, elevated serum levels of sTfR were associated with an increased risk of cardiovascular, pulmonary, and hematological manifestations, and with a decreased risk of neuropsychiatric manifestations. In contrast, elevated serum IL-4 levels were associated with a decreased risk of mucocutaneous manifestations.

Iron Status and Short-Term Recovery after Non-Severe Acute Myocarditis: A Prospective Observational Study

Pathomechanisms responsible for recovery from acute myocarditis (MCD) or progression to non-ischemic cardiomyopathy have not been comprehensively investigated. Iron, positioned at the crossroads of inflammation and the energy metabolism of cardiomyocytes, may contribute to the pathophysiology of inflammatory myocardial disease. The aim of this study was to evaluate whether systemic iron parameters are related to myocardial dysfunction in MCD patients. We prospectively enrolled 42 consecutive patients hospitalized for MCD. Their iron status and their clinical, laboratory, and echocardiographic indices were assessed during hospitalization and during ambulatory visits six weeks after discharge. A control group comprising healthy volunteers was recruited. The MCD patients had higher serum ferritin and hepcidin and lower serum iron concentration and transferrin saturation (TSAT) than the healthy controls (all p < 0.01). Six weeks after discharge, the iron status of the MCD patients was already comparable to that of the control group. During hospitalization, lower serum iron and TSAT correlated with higher NT-proBNP (both p < 0.05). In-hospital lower serum iron and TSAT correlated with both a lower left ventricular ejection fraction (LVEF) and worse left ventricular global longitudinal strain at follow-up visits (all p < 0.05). In conclusion, in patients with acute MCD, iron status is altered and normalizes within six weeks. Low serum iron and TSAT are related to greater in-hospital neurohormonal activation and subtle persistent left ventricular dysfunction.

Plasma iron controls neutrophil production and function

Low plasma iron (hypoferremia) induced by hepcidin is a conserved inflammatory response that protects against infections but inhibits erythropoiesis. How hypoferremia influences leukocytogenesis is unclear. Using proteomic data, we predicted that neutrophil production would be profoundly more iron-demanding than generation of other white blood cell types. Accordingly in mice, hepcidin-mediated hypoferremia substantially reduced numbers of granulocytes but not monocytes, lymphocytes, or dendritic cells. Neutrophil rebound after anti-Gr-1-induced neutropenia was blunted during hypoferremia but was rescued by supplemental iron. Similarly, hypoferremia markedly inhibited pharmacologically stimulated granulopoiesis mediated by granulocyte colony-stimulating factor and inflammation-induced accumulation of neutrophils in the spleen and peritoneal cavity. Furthermore, hypoferremia specifically altered neutrophil effector functions, suppressing antibacterial mechanisms but enhancing mitochondrial reactive oxygen species-dependent NETosis associated with chronic inflammation. Notably, antagonizing endogenous hepcidin during acute inflammation enhanced production of neutrophils. We propose plasma iron modulates the profile of innate immunity by controlling monocyte-to-neutrophil ratio and neutrophil activity in a therapeutically targetable system.

Ferritin Light Chain: A Candidate Autoantigen in Immuno-Related Pancytopenia

The characteristic feature of immune-related pancytopenia (IRP) is autoantibody-mediated bone marrow (BM) damage and peripheral blood cytopenia. We found that the potential antigen of IRP was Ferritin light chain (FTL) by SEREX (serological analysis of recombinant cDNA expression libraries) in the previous study. In this study, we tried to explore the antigenic epitopes of FTL and verify its antigenicity in IRP. We found the possible FTL epitope: VNLYLQASYTYLSLG by phage random peptide library. Through ELISPOT, it was found that peptide VNLYLQASYTYLSLG can significantly stimulate the production of interleukin-4 and cannot stimulate the production of interferon-γ, which suggested that the peptide can obviously activate Th2 cells. Peptide-major histocompatibility complex tetramer elicited antigen-specific T cell responses. The expression levels of FTL were significantly increased in the patients with untreated IRP (P < 0.05). In conclusion, we found that FTL is the target antigen for some patients with IRP. The peptide of VNLYLQASYTYLSLG is an epitope of the target antigen. The target antigen is abnormally overexpressed on the membrane of BM cells, especially on the surface of CD34+ BM cells of patients with IRP. In addition, it is related to the severity of disease. These results provide a possible new target for the treatment of IRP in the future.

Specific changes of erythroid regulators and hepcidin in patients infected by SARS-COV-2

Iron metabolism is tightly linked to infectious and inflammatory signals through hepcidin synthesis. To date, iron homeostasis during SARS-CoV-2 infection has not yet been described. The aim of this study is to characterize the hepcidin and erythroid regulators (growth differentiation factor 15 (GDF-15) and erythroferrone (ERFE)) by measuring concentrations in plasma in context of COVID-19 disease.We performed a single-center observational study of patients with COVID-19 to evaluate concentrations of main regulatory proteins involved in iron homeostasis, namely: hepcidin, ERFE and GDF-15. SARS-CoV-2 infection (COVID-19+) was defined by a positive RT-PCR. Sixteen patients with COVID-19+ were gender-matched and age-matched to 16 patients with a sepsis unrelated to SARS-CoV-2 (COVID-19-) and were compared with non-parametric statistic test.Clinical and hematological parameters, plasma iron, transferrin, transferrin saturation, ferritin, soluble transferrin receptor and C reactive protein were not statistically different between both groups. Median plasma hepcidin concentrations were higher in the COVID-19+ group (44.1 (IQR 16.55-70.48) vs 14.2 (IQR 5.95-18.98) nmol/L, p=0.003), while median ERFE and GDF-15 concentrations were lower in the COVID-19+ group (0.16 (IQR 0.01-0.73) vs 0.89 (IQR 0.19-3.82) ng/mL, p=0.035; 2003 (IQR 1355-2447) vs 4713 (IQR 2082-7774) pg/mL, p=0015), respectively) compared with the COVID-19- group.This is the first study reporting lower ERFE and GDF-15 median concentrations in patients with COVID-19+ compared with patients with COVID-19-, associated with an increased median concentration of hepcidin in the COVID-19+ group compared with COVID19- group.

The impact of sex on susceptibility to systemic lupus erythematosus and rheumatoid arthritis; a bioinformatics point of view

The unknown etiology of systemic autoimmune diseases, such as Systemic Lupus Erythematosus (SLE) and Rheumatoid Arthritis (RA), with a remarkable predominance of female, have prompted many researchers for unveiling the precise molecular mechanisms involved in this gender bias. In fact, depending on hormones and transcribed genes from sex chromosomes, at least, the initial mechanisms involved in pathogenesis might differ largely. With the aim of elucidating the above mechanisms, we have tried to specify the differentially expressed genes (DEGs) extracted from microarray libraries from both female and male SLE and RA patients. Subsequently, the androgen and estrogen receptor elements (ARE and ERE) among differentially expressed transcription factors (TFs) and the DEGs located on X or Y chromosomes have been determined. Moreover, the pathways regarding the common DEGs in both sexes are enriched. Our data revealed several ARE and ERE-containing genes (LCN2, LTF, RPL31, RPL9, RPS17, RPS24, RPS27L, S100A8, ABCA1, HIST1H2BD, ISG15, MAFB, GNLY, EVL, and HDC) to be associated with the related autoimmune disease and sex. Also, two DEGs (KDM5D and RPS4Y1) in SLE patients were determined to be on Y chromosome with one had been proved to be associated with autoantigens in SLE. Altogether, our data showed a number of plausible pathways in both autoimmune conditions together with the relevance of several sex-related genes in the mentioned diseases pathogenesis.

Cross-reaction between mouse and rat immunoglobulin G: does it matter in sandwich ELISA?

Background

Sandwich ELISA is an ideal antigen detection and quantification assay. Recently, it was used as the basic concept for high technology diagnostics. The specificity of the assay depends on the exclusion of detection cross-reactivity which arises from using two antibodies developed in different species. Since mice and rats are the common laboratory animals used to develop antigen specific antibodies. Therefore, the questions we addressed here were (1) can one use antigen-specific antibodies raised in mice and rats in the same assay to specifically detect/quantify antigens? and (2) which antibodies of the two rodents should be placed for capturing and for detection in the antigen-detection sandwich?

Results

Direct ELISA assay was used to assess for the specific reaction of the HRP-conjugated antibody to the target serum. First reaction was to compare between either conjugate anti-rat IgG (homologous) or anti-mouse IgG (heterologous) for the detection of rat sera IgG. Following the dilution factor optimization, the O.D. were 0.744±0.051 and 0.604±0.05, respectively (p= .004). The difference in mean O.D. of 0.14 reflected an unaccepted non-specific reaction. The second reaction was to compare between either conjugate anti-mouse IgG (homologous) and anti-rat IgG (heterologous) for the detection of mouse sera IgG. The recorded O.D. were 0.9414±0.14 and 0.317 ±0.141, respectively (p= .0002). The improved difference in mean O.D. of 0.624 reflecting a minimized cross-reaction.

Conclusions

Our results suggest that it is possible to use both Swiss albino mice and albino rats in a single sandwich ELISA, given that the captured antibody species to be from the Swiss albino mice and the detection antibody to be from the albino rat. The described working details are limited to the source of the antibodies used in the study. However, the approach stresses on the importance of such optimization steps before making any interpretations based on the antigen detection. To our knowledge, this study is the first to cover the optimal order of the capturing and the detection antibodies in a sandwich ELISA assay. In addition to addressing the possible interfering cross-reactivity that result from using mouse and rat serum antibodies in a single assay.

Graphical abstract

A Massive Primary Ovarian Abscess within an Endometrioma in a Young Nullipara – An Unusual Case and Review of Literature

Primary ovarian abscess without the involvement of the fallopian tube is a rare complication of an underlying endometrioma. Surgical interventions like ultrasound guided oocyte retrieval in in vitro fertilization and endometrioma aspiration may be a possible source of infection. De novo primary ovarian abscess within an endometrioma in the absence of a risk factor is even rarer. Decreased natural killer cell activity leads to a failure to clear out the ectopic endometrial tissue and the collected blood acts as a potential culture medium for the growth of pathogenic microorganisms. Infected ovarian endometrioma is a surgical emergency and preserving the fertility in a nullipara is a challenge. We report an unusual case of a massive de novo ovarian abscess masking an endometrioma in a young nulliparous woman with no risk factors. We have summarized current literature and evaluated the etiopathogenesis and the risk factors leading to abscess formation within an endometrioma.

Can Calprotectin Show Subclinical Inflammation in Familial Mediterranean Fever Patients?

BACKGROUND

Familial Mediterranean fever (FMF) is an autoinflammatory disease that has self-limiting inflammatory attacks during polyserositis. Hepcidin is a protein, and interleukin-6 stimulation increases hepcidin levels. Calprotectin (CLP) is a recently defined cytokine released from monocytes and neutrophils in response to tissue trauma and inflammation. There are studies in the literature showing that it can be used as a biomarker in rheumatic diseases such as ankylosing spondylitis and rheumatoid arthritis. Here, we compared the levels of hepcidin and CLP in healthy individuals and FMF patients during an attack-free period and show its relation to genetic mutations.

METHODS

This is a cross-sectional study. Between July 2017 and December 2017, 60 patients diagnosed with FMF an admitted to the Cumhuriyet University Faculty of Medicine Department of Internal Medicine Rheumatology as well as 60 healthy volunteers without any rheumatic, systemic, or metabolic diseases were enrolled in this study. Blood was collected from a peripheral vein to measure serum CLP and hepcidin levels. Blood tests were examined by ELISA; the study protocol was approved by the local ethics committee.

RESULTS

Median serum hepcidin level was 468.1 (210.3-807.8) pg/mL in FMF group and 890.0 (495.0-1,716.9) pg/mL in the healthy control (HC) group. There was a statistically significant difference between the two groups (P < 0.001). The median serum levels of CLP in the FMF group were measured as 1,331.4 (969.3-1,584.6 pg/mL and 73.8(45.0-147.9) pg/mL in the HC group. There was a statistically significant difference between the two groups (P < 0.001). Receiver operating characteristic analysis showed that the sensitivity was 66.7% and the specificity was 71.7% at serum hepcidin < 581.25 pg/mL (P < 0.05); the sensitivity was 96.7% and specificity was 100% at CLP > 238 pg/mL (P < 0.05). There was no significant difference between serum hepcidin and CLP levels in FMF patients with M694V homozygous and M694V heterozygous (P > 0.05). There was no significant difference in serum hepcidin levels between FMF patients with and without arthritis, proteinuria, and amyloidosis (P < 0.05). There was no significant correlation between laboratory findings, gender, age, and serum CLP and hepcidin levels (P > 0.05, r < 0.25).

CONCLUSION

Serum CLP levels in FMF patients during an attack-free period are significantly higher than in the HC groups. Serum hepcidin levels in FMF patients are significantly lower than in the HC group. Low levels of hepcidin may be explained by including FMF patients during an attack-free period in the study. CLP may be an important biomarker in FMF. A better understanding of the role of these biomarkers in the diagnosis of FMF is needed to evaluate the results in a more comprehensive way.

Effects of Ovariohysterectomy and Hyperbaric Oxygen Therapy on Systemic Inflammation and Oxidation in Dogs

Introduction: Hyperbaric oxygen therapy (HBOT) involves breathing 100% oxygen in a specialized compression chamber leading to hyperoxia. This treatment modality is associated with anti-inflammatory, antioxidant, and healing properties in people and laboratory animals. However, there are relatively few reports that evaluate the effects of HBOT in companion animals. The goal of this study was to investigate the physiological effects of HBOT on surgically induced systemic inflammation and oxidation in dogs.

Material and Methods: Twelve healthy female beagle dogs were spayed and randomized into control and HBOT groups (n = 6). Both groups received conventional post-ovariohysterectomy therapy, and the HBOT group received two hyperbaric treatments at 2.0 atmosphere of absolute pressure and 100% oxygen for 35 min, 6 and 18 h after surgery. Blood samples were collected 3 h prior to ovariohysterectomy, 6, 18, and 30 h after surgery, prior to HBOT when applicable. Inflammatory biomarkers, including C-reactive protein, circulating cytokines, and changes in iron homeostasis were evaluated at each time point to determine the effects of surgery and HBOT on inflammation. Similarly, serum total oxidant status and total antioxidant status were measured to assess the oxidative stress. Pain and incision scores were recorded and compared between groups.

Results: Following ovariohysterectomy, all dogs had significantly increased serum concentrations of C-reactive protein, KC-like, IL-6, and increased unsaturated iron-binding capacity compared to their pre-surgical values (p < 0.02), while serum iron, total iron-binding capacity and transferrin saturation were significantly decreased after surgery (p < 0.02). There was no significant difference between the control group and the HBOT group for any of the variables. There were no overt adverse effects in the HBOT group.

Conclusion: This is the first prospective randomized controlled study to investigate the effects of HBOT on surgically induced systemic inflammation in dogs. While elective ovariohysterectomy resulted in mild inflammation, the described HBOT protocol portrayed no outward adverse effect and did not induce any detectable pro-inflammatory, anti-inflammatory, or antioxidant effects. Additional investigation is required to identify objective markers to quantify the response to HBOT and determine its role as an adjunctive therapy in dogs with more severe, complicated or chronic diseases.

The hepcidin concentration decreases in hypothyroid patients with Hashimoto's thyroiditis following restoration of euthyroidism

The purpose of the study was to measure the hepcidin concentration and evaluate Fe homeostasis indices in a prospective study on patients with newly diagnosed hypothyroidism in the course of Hashimoto’s thyroiditis (HT) and following successful therapy. The prospective observational study consisted of 34 patients. The clinical evaluation and laboratory tests were performed at diagnosis (T0) and after restoration of euthyreosis 12 weeks later (T1). The median level of hepcidin was significantly lower (p = 0.002) after recovery (7.7 [6.2–13.0] ng/mL) than that before treatment (17.4 [7.6–20.4] ng/mL), while creatinine (p = 0.011) and GFR (p < 0.001) significantly improved after euthyroidism was achieved. A positive correlation was observed between hepcidin and fT3 (p = 0.033, r = 0.465) at T0. In the females, the level of hepcidin positively correlated with ferritin concentration before (p < 0.001, r = 0.928) and after treatment (p < 0.001, r = 0.835). A statistically significant difference was observed in RDW-CV (red blood cell distribution width - coefficient of variation) between the hypothyroid and euthyroid states. In conclusion, a decrease in hepcidin concentration during the transition from the hypothyroid state to euthyroidism in patients with HT is associated with the observed dynamics in iron homeostasis, mainly reflected by improvement in RDW-CV and significant correlations between ferritin and hepcidin as well as between hepcidin and fT3.