Creatine kinase and lactate dehydrogenase isoenzyme patterns in cultured normal and pathological gingival fibroblasts

The isoenzyme patterns of creatine kinase (CK) and lactate dehydrogenase (LDH) were examined in cultured fibroblasts derived from the gingival tissue of a healthy person and patients with periodontitis and gingival fibromatosis. Human foreskin fibroblasts were also included for comparison. Cytosol fractions were prepared by sonication and centrifugation. Gingival fibroblasts from normal subjects (A), and from patients with periodontitis (B) or fibromatosis (C), exhibited CK-MM (muscle form) as a predominant isoenzyme and CK-BB (brain form) as a minor fraction. There was no significant difference in specific activities of CK-BB fraction in all 3 types of fibroblasts. However, B fibroblasts contained a higher proportion of MM type isoenzyme than A fibroblasts. C fibroblasts showed the lowest amount of CK-MM isoenzyme as compared to either A or B fibroblasts. In contrast, fibroblasts derived from human foreskin (D) contained only a small amount of CK-BB isoenzyme, but CK-MM was not present. In the studies of LDH isoenzymes, A, B, and C fibroblasts possessed only 3 isoenzymes, namely, LDH-3, LDH-4 and LDH-5. In terms of the relative abundance of M vs H subunits, A, B, and C fibroblasts were shown to have a preponderance of M subunits (85-87% M vs 13-15% H subunits). In comparison, D fibroblasts contained 4 isoenzymes (LDH-2, LDH-3, LDH4, LDH-5) with 73% M and 27% H subunits. The ratio of LDH-5 to LDH-4 was calculated for all fibroblasts tested, and the values were 1.11 in A, 1.39 in B, 1.16 in C and 0.64 in D.(ABSTRACT TRUNCATED AT 250 WORDS)