Cysteine proteinase inhibitors decrease articular cartilage and bone destruction in chronic inflammatory arthritis.
OBJECTIVE
To determine the effects of peptidyl fluoromethyl ketones on the in vitro activity of purified cathepsins B and L, on tissue cysteine proteinase activity, and on cartilage and bone destruction in experimental arthritis.


METHODS
The effects of the fluoroketones on cathepsins B and L in vitro and the effects of oral administration of fluoroketones on ex vivo cysteine proteinase activity in tissue homogenates were determined by measuring the inhibition of fluorogenic substrate cleavage. To determine the effects on arthritis, animals were injected with adjuvant or type II collagen, treated orally with the fluoroketones, and the severity of arthritis was assessed by clinical, histologic, and radiologic methods.


RESULTS
All of the fluoroketones tested were potent inhibitors of purified cathepsins B and L activity. Oral administration of the fluoroketones reduced tissue cysteine proteinase activity by up to 77%. In addition, fluoroketone treatment significantly reduced the severity of clinical joint disease and decreased the destruction of articular cartilage and bone. Quantitative analysis of radiographic images indicated that treatment significantly reduced soft tissue changes, periosteal proliferation, and bone erosion, but only partially reduced juxtaarticular osteoporosis.


CONCLUSIONS
These studies suggest that cysteine proteinase inhibitors may limit tissue destruction in diseases such as rheumatoid arthritis.
Esser
R E
RE
Marion Merrell Dow Research Institute, Kansas City, Missouri.
Angelo
R A
RA
Murphey
M D
MD
Watts
L M
LM
Thornburg
L P
LP
Palmer
J T
JT
Talhouk
J W
JW
Smith
R E
RE
D000818:Animals; D001168:Arthritis / Q000139:chemically induced / Q000473:pathology*; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging / Q000503:physiopathology; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology*; D002358:Cartilage, Articular / Q000187:drug effects* / Q000473:pathology*; D002403:Cathepsins / Q000037:antagonists & inhibitors; D002908:Chronic Disease; D003094:Collagen; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004151:Dipeptides / Q000494:pharmacology; D005260:Female; D007659:Ketones / Q000494:pharmacology; D051379:Mice; D008811:Mice, Inbred DBA; D009025:Morpholines; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley
D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D007659:Ketones; D009025:Morpholines; C080182:P 34081; D003094:Collagen; D002403:Cathepsins