Periodontitis, a highly prevalent chronic, immune-mediated, inflammatory, infectious disease characterized by hard and soft periodontal tissue destruction, increases the risk of cognitive decline in the elderly. Similarly, periodontitis has been associated with hypertension and the systemic pro-inflammatory state posed by it could partially contribute to a rise in blood pressure (BP). Obesity and related metabolic disturbances including hypertension predict future cognitive decline. Periodontitis promotes inflammation of adipose tissue. Obese patients are in a generalized state of inflammation caused by actions of inflammatory cytokines and adipokines such as adipocytokines.  

Apelin (APLN), an adipocytokine secreted by visceral adipose tissue, is encoded by APLN gene, a preprotein of 77 amino acids. It is expressed in various organs including the brain and low serum levels of apelin have been observed in the mild cognitive impairment (MCI). Apelin is a potent effector that modulates vascular homeostasis and has effects on regulation of blood pressure by direct action on the vascular wall via paracrine effects or by affecting endothelial function. Serum and salivary concentrations of apelin are elevated in periodontitis.

Adiponectin, a 28-kDa protein adipocytokine, is mainly produced and secreted into the circulation by lean adipocytes. Adiponectin crosses the blood–brain barrier and acts as a neuroprotective molecule, with beneficial effects on hippocampal neurogenesis and cognitive function. Adiponectin lowers blood pressure by decreasing renal sympathetic nervous system activity. Serum adiponectin levels and expression of adiponectin receptors in periodontal tissues are decreased in patients with periodontitis. 

Scaling and root planing (SRP) reduces systemic inflammation and exposure to Porphyromonas gingivalis, reduces or delays the development of cognitive decline and causes significant reduction of systolic and diastolic BP. We therefore hypothesized that periodontitis, if positively associated with hypertension & cognition, SRP could lead to improvement in cognition and influence Apelin and Adiponectin levels. Till date, the role of apelin and adiponectin in the pathologic processes linking periodontal disease, hypertension and cognition is unclear. Hence the aim of the study is to correlate levels of salivary and serum apelin and adiponectin in individuals with generalized periodontitis and hypertension and to evaluate the effect of SRP on periodontal health, hypertension and cognition.