Three-sialic acid-specific lectins, Tritrichomonas mobilensis (TML) (w
ithout linkage preference), Maackia amurensis leukoagglutinin (MAL) (a
lpha 2, 3) and Sambucus nigra agglutinin (alpha 2,6 linkage-specific),
were used for detection of sialylated glycoconjugates in normal and d
iseased human kidneys. Normal kidneys demonstrated strong podocyte pos
itivity of alpha 2,3 linked sialic acid and weaker sialic acid express
ion on capillary endothelium, which was alpha 2,6 linked. Renal biopsi
es (45) representing a variety of diseases, e.g. minimal change diseas
e, membranous, membranoproliferative glomerulonephritis, tubulointerst
itial nephrosis or diabetic glomerulopathy showed increased sialic aci
d expression in glomerular capillaries, Bowman's capsule epithelium an
d on podocytes. In several different kidney diseases the glomerular en
dothelium expressed also alpha 2,3 linked sialic acid along with incre
ased TML-positivity of epithelial cells related to alpha 2,6 linked si
alic acid. No-difference in sialic acid linkage expression was observe
d in the tubules, which expressed putative alpha 2,6 linked sialic aci
d on the luminal surface of cells distal to the descending limb of Hen
le's loop. The study did not show changes characteristic of specific d
iseases. Rather, increased sialic acid expression on glomerular endoth
elium and podocytes was linked to a variety of pathological changes. I
t is assumed that changes in sialysation of glycoconjugates in the glo
meruli represent nonspecific changes and do not reflect fundamental pa
thogenetic features of renal diseases.