Neurornusc. Disord., Vol. 2, No. I. p. 59. 1992 Printed in Great Britain
0960-8966/92 $5.00 + 0.00 Pergamon Press Ltd
LETTER TO THE EDITOR STEROIDS IN D U C H E N N E M U S C U L A R DYSTROPHY MAYANAZATZ, RITA DE CASSIAM. PAVANELLO,MARIZ VA1NZOFand MARIA RITA PASSOS-BUENO Centro de miopatias, Departamento de Biologia, Instituto de Bioci~ncias. Universidade de S5o Paulo, S~o Paulo, Brazil
Recent investigations [1] have r e p o r t e d the beneficial effects o f c o r t i c o s t e r o i d t r e a t m e n t in D u c h e n n e muscular d y s t r o p h y ( D M D ) . A d o u b l e blind c o n t r o l l e d trial with the d r u g d e f l a z a c o r t (an oxazoline derivative o f p r e d n i s o l o n e ) in 28 D M D patients s h o w e d a statistically significant i m p r o v e m e n t in the t r e a t e d g r o u p ( N = 14) as c o m p a r e d with the a g e - m a t c h e d c o n t r o l g r o u p u n d e r p l a c e b o [2]. A l t h o u g h several investigators agree t h a t steroid t r e a t m e n t m a y diminish the rate o f p r o g r e s s i o n in D M D , the m e c h a n i s m s by which such d r u g s m i g h t i m p r o v e muscle strength a n d functional abilities are u n k n o w n . A decrease in the rate o f muscle b r e a k d o w n o r a h y p o t h e t i c a l a c t i v a t i o n o f an a l t e r n a t i v e p r o t e i n to d y s t r o p h i n has been suggested [2]. The beneficial effect o f g r o w t h h o r m o n e ( G H ) deficiency on the course o f D M D first r e p o r t e d by us [3, 4] has been c o n f i r m e d by others, b o t h in h u m a n s a n d a n i m a l m o d e l s [5-8]. H o w e v e r , t h e r a p e u t i c trials in D M D with M a z i n d o l were not successful since we have s h o w n t h a t this d r u g was n o t effective for p r o m o t i n g G H i n h i b i t i o n [9 11]. It is o u r suggestion t h a t the beneficial effect o f steroid a d m i n i s t r a t i o n might be also d u e to G H inhibition, which is one o f the k n o w n side-effects o f corticosteroids. In fact, in the recent r e p o r t o f M e s a et al. [2], a l t h o u g h n o t statistically significant (which c o u l d be due to the small size g r o u p , short d u r a t i o n o f the t r e a t m e n t o r i n d i v i d u a l differences in response to the drug), the stature increase d u r i n g the 9 m o n t h p e r i o d o f t r e a t m e n t was on average 0.8 c m g r e a t e r in the p l a c e b o t h a n in the t r e a t e d g r o u p .
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