Increase in type II collagen turnover after iron depletion in patients with hereditary haemochromatosis.
OBJECTIVE
To determine the effects of iron depletion on serum levels of joint biomarkers and on joint symptoms in patients with hereditary haemochromatosis (HH).


METHODS
Levels of biomarkers were measured in 18 patients with HH at the time of diagnosis and after iron depletion. The markers were type II collagen degradation (Coll2-1) and its nitrated form (Coll2-1NO(2)), type II procollagen synthesis (CPII), MPO, COMP and HA. For each patient, demographic data were collected and the global joint pain (visual analogue scale) was assessed before and after iron depletion by phlebotomy.


RESULTS
A total of 18 patients [10 males; mean (s.d.) age 48 (11) years] were homozygous for the C282Y mutation. No patient had liver dysfunction. Ferritin level before iron removal was 627.5 (range 133-3276) microg/l, and duration of the iron depletion phase was 295 (70-670) days. Serum levels of both Coll2-1 and CPII were significantly increased from diagnosis after iron depletion: 80.1 (55.6-113.5) vs 96.0 (48.8-136.3) nM (P = 0.004) and 731.4 (374.2-1012.3) vs 812.8 (535.8-1165.6) ng/ml (P = 0.03), respectively. Levels of other biomarkers were not modified by iron depletion. Ferritin level, which at baseline was correlated with body iron store (r = 0.63; P = 0.008), was significantly correlated with HA level measured before iron depletion (r = 0.60; P = 0.01). Global joint pain was not correlated with ferritin concentration and did not significantly decrease after iron depletion: 43 (19-73) vs 36 (16-67) mm (P = 0.07).


CONCLUSIONS
In patients with HH, cartilage homoeostasis is modified by iron excess and an increase in type II collagen turnover occurs after excess iron removal.
Richette
Pascal
P
Université Paris 7, UFR Médicale, Assistance Publique Hôpitaux de Paris, Hôpital Lariboisière, Fédération de Rhumatologie, Paris, France. pascal.richette@lrb.aphp.fr
Eymard
Claire
C
Deberg
Michelle
M
Vidaud
Dominique
D
de Kerguenec
Caroline
C
Valla
Dominique
D
Vicaut
Eric
E
Bardin
Thomas
T
Henrotin
Yves
Y
D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism*; D024043:Collagen Type II / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005293:Ferritins / Q000097:blood / Q000378:metabolism*; D006432:Hemochromatosis / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D006801:Humans; D007501:Iron / Q000378:metabolism; D000090463:Iron Deficiencies; D008297:Male; D008875:Middle Aged; D018962:Phlebotomy / Q000379:methods
D015415:Biomarkers; D024043:Collagen Type II; D005293:Ferritins; D007501:Iron