@entity2522 occurring when @entity2348 in the gingival crevice provides a convenient and interesting model for @entity32 in @entity1 . In some @entity1 , @entity2522 progresses to the destructive lesion of @entity2521 , involving the formation of periodontal pockets. The basis for pocket formation and progression is not as yet clear, although neutrophilic polymorphonuclear leukocytes (PMN) appear to play a protective role. Vascular changes appear to either facilitate or inhibit PMN function with the effect of either protecting from, or stimulating, @entity2521 . Contrary to most circumstances, high endothelial cells in @entity2521 are involved with PMN rather than lymphocyte emigration. Expansion of the microvasculature through increased vascular diameter and tortuosity as well as the development of high endothelial cells appears to protect from @entity2521 by increasing the supply of both plasma defense factors and PMN to the tissues. Vascular changes that may oppose this and promote @entity2521 are the formation of perivascular hyaline material and accumulation of basement membrane rests. The inadequate tissue turnover that accumulation of these vascular products represents can be argued as a vascular response to a @entity32 that has failed to eliminate the irritant. It is suggested that these vascular changes may account for the highly localized and burst-like pattern of pocket formation in @entity2521 . Finally, it is possible that the recent observation that @entity2521 is an independent risk factor for @entity455 may reflect stimulation of acute phase protein synthesis by cytokines released by periodontal high endothelial cells.

Microvasculature in @entity2522 and chronic periodontitis: @entity455 with protracted XXXX .

@entity1 :: ('9606', 'Species') :: ['humans', 'patients'] @entity32 :: ('MESH:D007249', 'Disease') :: ['chronic inflammation'] @entity455 :: ('MESH:D014652', 'Disease') :: ['systemic vascular disease'] @entity2522 :: ('MESH:D005891', 'Disease') :: ['gingivitis', 'Gingivitis'] @entity2348 :: ('MESH:D001424', 'Disease') :: ['bacterial plaque accumulates'] @entity2521 :: ('MESH:D010518', 'Disease') :: ['periodontitis']
@entity32 :: (MESH:D007249,Disease) :: ['inflammation']
