C. Cloos et al., URINARY GLYCOSYLATED, FREE AND TOTAL PYRIDINOLINE AND FREE AND TOTAL DEOXYPYRIDINOLINE IN DIABETES-MELLITUS, Clinical endocrinology, 48(3), 1998, pp. 317-323
OBJECTIVE Published data on bone metabolism in diabetes mellitus are c
onflicting, We have measured pyridinium crosslinks, biochemical marker
s of bone resorption, in order to evaluate bone resorption in diabetes
mellitus. We also wished to investigate whether, as a consequence of
chronic hyperglycaemia, pyridinoline is glycosylated to a greater exte
nt in patients with diabetes mellitus, DESIGN AND PATIENTS This cross
sectional study included 142 patients (64 males, 78 females) with insu
lin dependent and non-insulin dependent diabetes mellitus (IDDM and NI
DDM). These patients were compared to a healthy control group of 99 in
dividuals (39 males and 60 females), MEASUREMENTS Pyridinium crosslink
s, glycosylated, free and total pyridinoline (gPYD, fPYD, tPYD) and fr
ee and total deoxypyridinoline (fDPD, tDPD) were measured in a spot ur
ine sample by high performance liquid chromatography (HPLC). Urinary c
reatinine, albumin and glucose were also measured, RESULTS In the diab
etic group, values of urinary gPYD and tDPD were significantly lower t
han in controls. gPYD excretion was lowest in patients with severe gly
cosuria. Free pyridinium crosslinks, both fPYD and fDPD, were excreted
to a significantly lower extent, The molar ratio of tPYD to tDPD was
significantly increased in diabetes mellitus, CONCLUSIONS Decreased ex
cretion of tDPD suggests low bone resorption in IDDM and NIDDM, Pyridi
noline is not glycosylated to a greater extent in diabetes mellitus an
d tends to be decreased in proportion to the degree of glycosuria. Exc
retion of gPYD, fPYD and fDPD is depressed in severe glycosuria. Dimin
ished degradation to the final products, fPYD and fDPD, might represen
t increased resistance to enzymatic activity or diminished enzymatic a
ctivity, The increased molar ratio tPYD/tDPD in urine suggests an incr
eased ratio in bone collagen in diabetes mellitus.