CHAPTER 4
 DISCUSSION

 In the present study expression of the IGF-1 receptor has been revealed on gingival

tissue samples of both self reported Type 2 diabetics with periodontal disease as well as

gingival tissue samples of self reported healthy non-diabetic subjects with periodontal

disease. Although statistical significance could not be established between both groups

certain trends were apparent. A trend for increased expression of IGF-1 receptors in

diabetics as well as a decreased expression in controls was obvious (see figure 3-3).

These results are consistent with previous studies showing that the expression of the IGF-

1 receptor is up-regulated in diabetes [95, 96, 97, and 98].

 The role of the IGF system in the pathogenesis of diabetes and diabetic

complications is speculative at this point in time. There is a growing body of evidence

that for its role in mirovascular complications and its ability to mediate the proliferative

features of these complications. The tissue-specific nature of these complications in the

context of a systemic metabolic disturbance suggests the possibility of autocrine or

paracrine dysregulation which may be mediated at a number of levels: increased local

IGF production, increased sequestration of circulating IGF by IGF binding proteins, or

tissue specific increases in IGF receptor numbers [112].

 Studies of circulating IGF-1 levels in diabetic patients for the most part have

demonstrated decreased IGF-1 levels (50-90%) [113]. Although there have been some

studies that showed normal or elevated levels [114]. The relationship between glycemic

control and IGF-1 is also not quite definitive. Most studies have found an inverse