0
selected
-
1.
Nasal Levels of Antimicrobial Peptides in Allergic Asthma Patients and Healthy Controls: Differences and Effect of a Short 1,25(OH)2 Vitamin D3 Treatment.
Thijs, W, Janssen, K, van Schadewijk, AM, Papapoulos, SE, le Cessie, S, Middeldorp, S, Melissant, CF, Rabe, KF, Hiemstra, PS
PloS one. 2015;(11):e0140986
Abstract
BACKGROUND Allergy is often accompanied by infections and lower levels of antimicrobial peptides (AMPs). Vitamin D has been shown to increase expression of selected AMPs. In this study we investigated whether antimicrobial peptide levels in nasal secretions of allergic asthma patients are lower than in healthy controls, and whether administration of the active form of vitamin D (1,25(OH)2D3) affects these antimicrobial peptide levels. METHODS The levels of antimicrobial peptides in nasal secretions were compared between 19 allergic asthma patients and 23 healthy controls. The effect of seven days daily oral treatment with 2 μg 1,25(OH)2D3 on antimicrobial peptides in nasal secretions was assessed in a placebo-controlled cross-over clinical study. RESULTS Levels of neutrophil α-defensins (human neutrophil peptides 1-3; HNP1-3) and lipocalin 2 (LCN2; also known as NGAL) were significantly lower in asthmatics, but no differences in LL-37 and SLPI were detected. Treatment with a short-term 1,25(OH)2D3 caused a small increase in HNP1-3, but not when the asthma and control groups were analyzed separately. LL-37, LCN2 and SLPI did not change after treatment with 1,25(OH)2D3. CONCLUSION Levels of the antimicrobial peptides HNP1-3 and LCN2 are lower in nasal secretions in asthmatics and are not substantially affected by a short-term treatment with active vitamin D.
-
2.
Hepcidin levels predict nonresponsiveness to oral iron therapy in patients with iron deficiency anemia.
Bregman, DB, Morris, D, Koch, TA, He, A, Goodnough, LT
American journal of hematology. 2013;(2):97-101
-
-
Free full text
-
Abstract
Levels of hepcidin, a major regulator of iron homeostasis, may identify patients with iron deficiency anemia (IDA) who will not respond to oral iron therapy. In this study, IDA patients underwent a 14-day trial (run-in) course of ferrous sulfate therapy. Nonresponders (Hgb increase <1 g/dL with 67% compliance rate) were randomized to IV ferric carboxymaltose (FCM; two injections of 750 mg) or further oral iron for 14 days. Screening hepcidin levels were 38.4 versus 11.3 ng/mL, P = 0.0002 in nonresponders versus responders to a trial of oral iron. Hepcidin of > 20 ng/mL, showed sensitivity of 41.3%, specificity of 84.4%, and positive predictive value of 81.6% for predicting nonresponsiveness to oral iron. PPVs for ferritin> 30 ng/mL or transferrin saturation (TSAT)>15% were 59.2 and 55%, respectively. Negative predictive values for hepcidin, ferritin, and TSAT were 46.3, 22.7, and 19.7, respectively. FCM versus oral iron showed Hgb increases of ≥ 1 gm/dL in 65.3% versus 20.8% (P < 0.0001) and Hgb increases of 1.7 ± 1.3 versus 0.6 ± 0.9 g/dL (P = 0.0025), respectively. We conclude that hepcidin predicts nonresponsiveness to oral iron in patients with IDA and is superior to TSAT or ferritin for this purpose. Nonresponse to oral iron therapy does not rule out IDA, since two-thirds of patients subsequently responded to intravenous iron.
-
3.
The effects of acute exercise bouts on hepcidin in women.
Newlin, MK, Williams, S, McNamara, T, Tjalsma, H, Swinkels, DW, Haymes, EM
International journal of sport nutrition and exercise metabolism. 2012;(2):79-88
Abstract
PURPOSE To investigate the effects of acute exercise on serum hepcidin and iron (sFe) in active women. Changes in interleukin-6 (IL-6), hepcidin, ferritin, and sFe in response to 2 different exercise durations were compared. METHODS Twelve women age 19-32 yr performed 2 treadmill runs (60 and 120 min) at 65% of VO2max. Blood samples were obtained before, immediately after, and 3, 6, 9, and 24 hr after exercise. Two-way repeated-measures ANOVA was conducted to examine changes in measured variables. Significance was accepted at p < .05. RESULTS Significant effects for trial were observed for hepcidin (60 min: 1.15 ± 0.48 nmol/L; 120 min: 2.28 ± 1.44 nmol/L) and for time, with hepcidin significantly increased 3 hr postexercise in both trials (60 min: 3 hr - 1.99 ± 2.00 nmol/L; 120 min: 3 hr - 4.60 ± 4.61 nmol/L). Significant main effects for time occurred for sFe, ferritin, and IL-6. sFe was significantly decreased 9 hr postexercise compared with 3 and 24 hr postexercise. IL-6 was significantly increased immediately postexercise. CONCLUSIONS Both runs resulted in significant increases in hepcidin 3 hr after exercise. Increases in hepcidin were preceded by significant increases in IL-6 immediately postexercise and followed by significant decreases in sFe 9 hr postexercise. It was concluded that endurance exercise increases the production of hepcidin, which affects sFe. The 2-hr exercise bout stimulated greater changes in serum hepcidin than the 1-hr bout.
-
4.
Hepcidin-25 is a marker of the response rather than resistance to exogenous erythropoietin in chronic kidney disease/chronic heart failure patients.
van der Putten, K, Jie, KE, van den Broek, D, Kraaijenhagen, RJ, Laarakkers, C, Swinkels, DW, Braam, B, Gaillard, CA
European journal of heart failure. 2010;(9):943-50
Abstract
AIMS: Erythropoietin (EPO) resistance, an important cause of anaemia in patients with heart and renal failure, is associated with increased mortality. The hypothesis of the present study was that exogenous EPO decreases hepcidin levels and that the decrease in hepcidin levels upon EPO treatment is related to the bone marrow response. METHODS AND RESULTS In the EPOCARES trial, patients with renal failure (glomerular filtration rate 20-70 mL/min), heart failure, and anaemia were randomized to receive 50 IU/kg/week EPO (n = 20) or not (n = 13). Haemoglobin (Hb), hepcidin-25, ferritin, reticulocytes, serum transferrin receptor (sTfR), IL-6, and high-sensitivity C-reactive protein were measured at baseline and during treatment. Hepcidin-25 was measured by weak cation exchange chromatography/matrix assisted laser desorption ionization time-of-flight mass spectrometry. Baseline hepcidin levels were increased compared with a healthy reference population and were inversely correlated with Hb (r(2) = 0.18, P = 0.02), and positively with ferritin (r(2) = 0.51, P < 0.001), but not with renal function, high-sensitivity C-reactive protein or IL-6. Erythropoietin treatment increased reticulocytes (P < 0.001) and sTfR (P < 0.001), and decreased hepcidin (P < 0.001). Baseline hepcidin levels and the magnitude of the decrease in hepcidin correlated with the increase in reticulocytes (r(2) = 0.23, P = 0.03) and sTfR (r(2) = 0.23, P = 0.03) and also with the Hb response after 6 months (r(2) = 0.49, P = 0.001). CONCLUSION In this group of patients with combined heart and renal failure and anaemia, increased hepcidin levels were associated with markers of iron load and not with markers of inflammation. The (change in) hepcidin levels predicted early and long-term bone marrow response to exogenous EPO. In our group hepcidin seems to reflect iron load and response to EPO rather than inflammation and EPO resistance.
-
5.
HAMP promoter mutation nc.-153C>T in 785 HEIRS study participants.
Barton, JC, Leiendecker-Foster, C, Li, H, DelRio-LaFreniere, S, Acton, RT, Eckfeldt, JH, ,
Haematologica. 2009;(10):1465; author reply 1465-6
-
6.
Sequence analysis and membrane partitioning energies of alpha-helical antimicrobial peptides.
Han, X, Kang, W
Bioinformatics (Oxford, England). 2004;(6):970-3
Abstract
Sequences of 221 alpha-helical antimicrobial peptides (alphaAMPs) were compared and 63-166 of them were selected and analyzed using Perl programs. The results showed that aliphatic amino acids Gly, Leu, Ala, Ile and two positively charged amino acids Lys and Arg were composed of more than 63% of the first 20 residues of alphaAMPs. The weighed mean membrane partitioning energies at positions from 1 to 25 of alphaAMPs were calculated. Profile of the partitioning energies suggests oblique membrane insertion and an amphipathic alpha-helical structure of the N-terminus of alphaAMP (residues from 1 to 13), a bend structure at positions 13 and 14, and a less structured C-terminus that parallels the surface of the membrane. These structural features are in good agreement with the experimentally determined membrane structure of hemagglutinin fusion peptide from influenza virus. We hypothesize that this (N-terminal oblique alpha-helix)-central bend-(C-terminus) could be a common structural motif of membrane-disruptive peptides.