Zonulin and iron metabolism in heart transplant recipients.
BACKGROUND
In patients after heart transplantation, anemia is relatively common and is associated with impaired kidney function, subclinical inflammatory state, and immunosuppressive treatment. Zonulin-prehaptoglibin-2 is newly discovered protein with poorly defined function. Hemoglobin binds haptoglobin, and this stable complex prevents oxidative stress caused by hemoglobin. Zonulin is necessary for integrity of intracellular tight junction in the gut. Taking into consideration iron metabolism, including its absorption in the gut, the aim of this study was to assess zonulin levels in heart transplant recipients and their possible correlations with iron status, immunosuppressive therapy, and kidney function.


METHODS
The study was performed with 80 stable heart transplant recipients and 22 healthy volunteers. Zonulin, iron status, and inflammatory markers were assessed with the use of commercially available kits.


RESULTS
Zonulin correlated with intraventricular diameter (r = 0.30; P < .05), right ventricle systemic pressure (r = 0.27; P < .05), and hemoglobin (r = 0.21; P < .05). There were no correlations between zonulin and iron status. Zonulin was significantly lower in heart transplant recipients than in healthy volunteers (P < .001). Kidney function, immunosuppressive regimen, New York Heart Association functional class, sex, and presence of anemia did not affect zonulin level.


CONCLUSIONS
Zonulin, despite its effect on the absorption of different nutrients and other substances and hypothethic role in oxidative stress, seems not to play a role in the pathogenesis of anemia in heart transplant recipients. Its physiologic role remains obscure.
Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, John Paul II Hospital, Cracow, Poland. Electronic address: piotr.przybylowski@uj.edu.pl.
P
P
Przybyłowski
Department of Internal Medicine and Angiology, Brothers Hospitallers' of St John of God Hospital, Cracow, Poland.
E
E
Nowak
Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, John Paul II Hospital, Cracow, Poland.
L
L
Janik
Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, John Paul II Hospital, Cracow, Poland.
G
G
Wasilewski
Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, John Paul II Hospital, Cracow, Poland.
S
S
Kozlowska
Department of Nephrology and Transplantology, Medical University, Bialystok, Poland.
J
J
Małyszko
D000328:Adult; D000740:Anemia / Q000097:blood* / Q000150:complications / Q000378:metabolism; D015415:Biomarkers; D016022:Case-Control Studies; D002772:Cholera Toxin / Q000097:blood*; D005260:Female; D006084:Graft Rejection / Q000517:prevention & control*; D006242:Haptoglobins; D016027:Heart Transplantation; D006454:Hemoglobins; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007249:Inflammation; D007501:Iron / Q000097:blood* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011498:Protein Precursors; D051437:Renal Insufficiency / Q000097:blood* / Q000150:complications; D066027:Transplant Recipients
D015415:Biomarkers; C485359:HP protein, human; D006242:Haptoglobins; D006454:Hemoglobins; D007166:Immunosuppressive Agents; D011498:Protein Precursors; C408043:zonulin; D002772:Cholera Toxin; D007501:Iron