The Klotho gene was initially identified as an aging suppressor gene, but subsequent research revealed its multifaceted functions, encompassing antioxidant defense, anti-inflammatory effects, calcium and phosphorus balance, metabolic regulation, and anti-apoptotic activity. It encodes a single pass transmembrane protein and is expressed primarily in renal tubules. The Klotho protein exists in two forms: membrane-bound and secreted. Membrane Klotho acts as a co-receptor for FGF23, a bone-derived hormone, while secreted Klotho regulates various cell surface glycoproteins, including ion channels and growth factor receptors. Klotho has recently emerged as a potential biomarker for coronary heart disease, with evidence suggesting its involvement in the disease's pathophysiology.
The red complex, comprising Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia harbors key pathogens in adult periodontal disease. These bacteria possess various virulence factors, including fimbriae, lipopolysaccharides, and proteases in P. gingivalis, which disrupt inflammatory and immune responses and degrade connective tissue proteins. T. forsythia produces a trypsin-like protease, sialidase, hemagglutinin, and BspA, contributing to alveolar bone loss. Meanwhile, T. denticola disrupts the host cell extracellular matrix, penetrates tissue, and dysregulates immunoregulatory factors, further exacerbating periodontal disease. Similarly, Herpes Simplex Virus 1 (HSV-1), human Cytomegalovirus (HCMV) and Epstein Barr Virus (EBV) have been implicated in the pathogenesis of periodontal disease. The expressions of viruses along the red complex bacteria would provide further evidence of periodontal risk in progression of acute coronary artery disease.