Interstitial expression of heat shock protein 47 and alpha-smooth muscle actin in renal allograft failure.
BACKGROUND
Tubulointerstitial inflammation and fibrosis are the main pathological features of chronic renal allograft rejection, which is characterized by accumulation of extracellular matrix protein. Heat shock protein 47 (HSP47), known as a collagen-specific stress protein, is thought to be a molecular chaperone during the processing and/or secretion of procollagen. HSP47 is thought to be involved in the progression of fibrosis, but its expression in chronic renal allograft rejection is still unknown.


METHODS
We examined the expression of HSP47 together with that of alpha-smooth muscle actin (alpha-SMA), a marker of myofibroblasts, and CD68, a marker of macrophages, by immunohistochemistry in allograft kidney tissues. Uninvolved portions of surgically removed kidneys with tumours served as control tissue.


RESULTS
Expression of HSP47 was detected in the interstitium of fibrotic regions of allograft kidneys. Cells positive for HSP47 were also stained for alpha-SMA and type I collagen, and the expression of HSP47 correlated with the degree of interstitial fibrosis. Furthermore, the expression of HSP47 correlated with the number of infiltrating macrophages. In contrast, HSP47 and alpha-SMA were not expressed in the control tissues, sections of 1 h post-transplantation biopsy specimens and acute allograft rejection without fibrosis.


CONCLUSIONS
Our results suggest that HSP47 may contribute to the progression of interstitial fibrosis in allograft renal tissues.
Abe
K
K
Second Department of Internal Medicine, Department of Histology and Cell Biology, Nagasaki University School of Medicine, Sakamoto, Nagasaki.
Ozono
Y
Y
Miyazaki
M
M
Koji
T
T
Shioshita
K
K
Furusu
A
A
Tsukasaki
S
S
Matsuya
F
F
Hosokawa
N
N
Harada
T
T
Taguchi
T
T
Nagata
K
K
Kohno
S
S
D000199:Actins / Q000378:metabolism*; D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D015415:Biomarkers; D001706:Biopsy; D003094:Collagen / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006084:Graft Rejection / Q000378:metabolism*; D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D016030:Kidney Transplantation; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009210:Myofibrils / Q000378:metabolism / Q000473:pathology; D014184:Transplantation, Homologous; D000097382:CD68 Molecule
D000199:Actins; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D003094:Collagen; D050958:HSP47 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C494660:SERPINH1 protein, human