Rj. Anderson et al., RETINOIC ACID REGULATION OF RENAL TUBULAR EPITHELIAL AND VASCULAR SMOOTH-MUSCLE CELL-FUNCTION, Journal of the American Society of Nephrology, 9(5), 1998, pp. 773-781
Vitamin A and its derivatives have been postulated to play an importan
t role in renal tubulogenesis and compensatory hypertrophy. This study
examined the effects of two carboxylic derivatives of vitamin A on Le
wis lung carcinoma-porcine kidney-1 (LLC-PK1) renal tubular epithelial
cell mito-and motogenesis and cell size. It was found that all-trans
and 13-cis retinoic acids exerted modest, dose-dependent effects to st
imulate incorporation of H-3-thymidine into acid-precipitable material
of LLC-PK1 cells. The effects of all-trans retinoic acid to promote H
-3-thymidine uptake in LLC-PK1 cells modestly enhanced that seen with
acidic fibroblastic growth factor. Similar findings of these two retin
oic acid derivatives to promote H-3-thymidine uptake and to enhance H-
3-thymidine uptake stimulated by another growth factor (platelet-deriv
ed growth factor BB) were also observed in cultured bovine aortic smoo
th muscle cells. Both retinoic acids promoted healing of denuded areas
made within confluent monolayers of serum-starved LLC-PK1 cells. All-
trans retinoic acid also stimulated recovery of mechanically denuded a
reas within bovine aortic smooth muscle monolayers. Neither all-trans
nor 13-cis retinoic acids affected cell size as assessed by forward li
ght scatter with flow cytometry, suggesting lack of effect to induce h
ypertrophy. These results demonstrate that two carboxylic acid derivat
ives of vitamin A are capable of stimulation of basal and growth facto
r-induced incorporation of H-3-thymidine uptake into acid-precipitable
material and healing of denuded areas in disparate cell types. These
findings are compatible with a role for vitamin A and its analogues in
the tissue repair process.