ISFIBROBLAST HETEROGENEITY RELEVANTTO THEHEALTH,DISEASES, AND TREATMENTSOFPERIODONTAL TISSUES?

There arewidevariations ofgeneexpression andstrikingly different responses toextracellular signals amongdif- ferent fibroblast populations. Thishasprompted alarge numberofinvitro studies which suggest that fibroblasts arenot homogeneous butinstead comprise multiple subpopulations withextensive site-to-site andintra-site variations. Conceivably, either fibroblasts arenotallcreated equal, or,alternatively, discrete subpopulations mayemerge indevelop- ment, inflammatory lesions, orwoundhealing. While theheterogeneous nature ofcultured fibroblasts hasbeenknownfor sometime, arethese variations relevant toourunderstanding ofthebiology oforal tissues, their involvement indisease, and their response totherapy? Since fibroblasts arethepredominant cell typeinsoft connective tissue matrices, theregulation oftheir proliferative, synthetic, anddegradative behavior islikely tobeimportant intissue physiology andpathology. Inthis review, weusethecurrent literature toassess whether fibroblast subpopulations really makeadifference inthehealth and disease ofperiodontal tissues. Weaddress thefollowing questions: (1)Isfibroblast heterogeneity areal invivo phenomenon? (2)Howcanweadvance ourknowledge ofphenotypic variations andtheregulation offibroblast differentiation? (3)Could a knowledge offibroblast heterogeneity haveanimpact onthedevelopment ofnewapproaches topathogenesis andthetreat- mentofperiodontal tissues?