Possible involvement of mast cells in renal fibrosis in patients with IgA nephropathy.
OBJECTIVE
The objective of the present study is to investigate whether human mast cells (MC) contribute to renal damage through local activation of the renin-angiotensin system, by assessing their numbers in renal biopsy specimens from patients with IgA nephropathy (IgAN) or minimal change nephrotic syndrome (MCNS).


METHODS
In patients with IgAN and MCNS, the numbers of tryptase-positive MC (MC(T)) and MC positive for both tryptase and chymase (MC(TC)) were examined histopathologically. Serum creatinine level, mean blood pressure and the severity of glomerular and tubulointerstitial lesions were also determined.


RESULTS
MC(TC) numbers differed between IgAN patients and MCNS patients. IgAN patients had more MC(TC) than MC(T). MC were found around but not in the conglomerate of the AngiotensinII (AngII)-positive cells. In the IgAN patients with the most severe pathology, the number of AngII-positive cells was correlated with that of MC(TC) and MC(T).


CONCLUSIONS
Chymase-dependent AngII synthesis due to human MC may be involved in the inflammatory and fibrotic processes of IgAN.
Sakamoto-Ihara
T
T
Division of Nephrology, Department of Internal Medicine, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Suzuki
Y
Y
Kurusu
A
A
Yamashita
M
M
Horikoshi
S
S
Tomino
Y
Y
D000293:Adolescent; D000328:Adult; D000368:Aged; D000804:Angiotensin II / Q000032:analysis; D015550:Cell Degranulation; D005260:Female; D005355:Fibrosis; D005922:Glomerulonephritis, IGA / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008297:Male; D008407:Mast Cells / Q000502:physiology*; D008875:Middle Aged; D009402:Nephrosis, Lipoid / Q000473:pathology
D000804:Angiotensin II