Localized aggressive periodontitis (LAP) affects 70,000 US children, largely from underserved communities. If untreated social and psychological stigma resulting from tooth loss can occur. This study is designed to identify early markers of aggressive periodontitis (eMAPs). Risk markers that include Aggregatibacter actinomycetemcomitans (Aa), other microbes, and host response elements will be examined over time. Adolescents will be screened to select a balanced cohort of 250 Aa-positive and 250 Aa-negative periodontally healthy students who will be enrolled and followed for 2 years. The purpose of this study is to detect microbial and host biomarkers that precede clinical evidence of bone loss (BL) with the aim of developing a chair-side diagnostic system for rapid identification of susceptible subjects. Thus far, we have developed a test that permits immediate chair-side identification of subjects with Aa, and a test for chemokines related to BL. However, our data indicates that Aa alone is not sufficient for diagnosis, and macrophage inflammatory protein 1-alpha (MIP-1?) while novel and related to BL can be improved upon by finding markers that identify earlier events. Clinical measurements and sampling of buccal epithelial cells (BECs), saliva, plaque, and crevice fluid will be performed every 3 months. Stored samples will be analyzed prospectively to assess host and microbial biomarkers (salivary, crevicular and microbial elements) that predate BL (Aa and MIP-1a) and predict bone loss in a subject (AIM 1a) and at a site (AIM 1b), and then to retrospectively determine new biomarkers that predate BL when a subject (AIM 2a) and a site develops radiographic signs of BL (AIM 2b).
AIM 1 a assesses whether Aa on buccal cells in combination with salivary MIP-1?, an osteoclast promoter, can serve as predictive diagnostic markers for individuals who will develop LAP.
AIM 1 b assesses levels of: 1) the proposed antagonists (a consortium of subgingival bacteria including Aa, S. parasanguinis and F. alocis), and 2) host response element (crevicular MIP-1?) as predictive markers of time-dependent risk for BL at a tooth sites within 6-9 months.
AIM 2 examines host and microbial markers that appear earlier than markers tested in AIM 1. After detection of BL, samples taken 3, 6, 9, and 12 months earlier will be tested for salivary and microbial factors that could promote colonization of the consortium on BECs at the subject level (AIM 2a). At the site level we will study the orchestration and timing of individual bacteria that make up the subgingival LAP consortium to determine if previously undetected bacteria (using NextGen sequencing) may also be involved in disease initiation. Further, sequential timing of early, middle, and late host cytokines as they appear in crevice fluid will be analyzed to identify biomarkers (AIM 2b) appearing at a BL site in advance of markers studied in AIM 1. Our premise is that the knowledge gained can provide sensitive and specific biomarkers that can supplant diagnostic tools used currently in practice. In this manner, subjects at risk can be identified in the earliest stages of disease so that cost-effective strategies can be instituted to reduce oral health disparities.
We have developed a unique clinical model that permits us to examine and offer treatment to vulnerable underserved adolescent subjects as they progress from health to the early stages of localized aggressive periodontal disease. The current study design will provide us with the opportunity to evaluate subjects and sites within subjects every 3 months so that biomarkers discovered in our previous grant period can be used to predict bone loss in these subjects and sites that start out healthy and progress to disease. In addition, oral samples taken at 3-month intervals will now also be assessed after disease occurs to find new biomarkers that arise at earlier stages of disease by evaluating these biomarkers before disease was detected in order to translate these biomarkers into diagnostic tests to provide cost-effective preventive interventions that can reduce oral health disparities in underserved adolescent populations vulnerable to this aggressive form of periodontal disease.
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