Is retinoic acid required for the initiation of outgrowth in the chick limb bud?
RA, in conjunction with Fgf-8, may be needed for the induction of the chick limb bud and the induction of Shh and Fgf-4 expression. The expression of Shh and Fgf-4 remains dependent upon the continued synthesis of RA within the limb bud. Didehydroretinoic acid is the major active retinoid in the stage 20 chick limb bud.
These results suggest a relationship between CC-chemokine system and KP activation, which may represent one of the mechanisms involved in the accelerated atherosclerosis in CKD population.