Heat-shock protein 60 kDa and atherogenic dyslipidemia in patients with untreated mild periodontitis: a pilot study

Abstract

Identification of predictors of cardiovascular risk can help in the prevention of pathologic episodes and the management of patients at all stages of illness. Here, we investigated the relationships between serum levels of Hsp60 and dyslipidemia in patients with periodontitis by performing a cross-sectional study of 22 patients with mild periodontitis without any prior treatment for it (i.e., drug naïve) and 22 healthy controls, matched for age and body mass index (BMI). All subjects were evaluated for periodontal status, gingival inflammation, and oral hygiene. Levels of circulating Hsp60, C-reactive protein (CRP), and plasma lipids were measured, and small, dense low-density lipoproteins (LDL) were indirectly assessed by determining the triglycerides/high-density lipoproteins (HDL) cholesterol ratio. We also assessed by immunohistochemistry Hsp60 levels in oral mucosa of patients and controls. No difference was found in CRP levels or plasma lipids between the two groups, but subjects with periodontitis showed, in comparison to controls, higher levels of small, dense LDL (p = 0.0355) and circulating Hsp60 concentrations (p < 0.0001). However, levels of mucosal Hsp60 did not change significantly between groups. Correlation analysis revealed that circulating Hsp60 inversely correlated with HDL-cholesterol (r = -0.589, p = 0.0039), and positively with triglycerides (r = +0.877, p < 0.0001), and small, dense LDL (r = +0.925, p < 0.0001). Serum Hsp60 significantly correlated with the degree of periodontal disease (r = +0.403, p = 0.0434). In brief, untreated patients with mild periodontitis had increased small, dense LDL and serum Hsp60 concentrations, in comparison to age- and BMI-matched controls and both parameters showed a strong positive correlation. Our data indicate that atherogenic dyslipidemia and elevated circulating Hsp60 tend to be linked and associated to periodontal pathology. Thus, the road is open to investigate the potential value of elevated levels of circulating Hsp60 as predictor of risk for cardiovascular disease when associated to dyslipidemia in periodontitis patients.

Fig. 1

Correlations between Hsp60 levels in blood and clinical parameters. Spearman correlations between Hsp60 and degree of periodontal pathology (upper panel) and between Hsp60 and small, dense LDL, as indirectly assessed by the triglycerides/HDL-cholesterol ratio (bottom panel), in patients with mild periodontitis

Fig. 2

Immunostaining for Hsp60 in periodontal mucosa. The non-parametric Mann–Whitney test showed the absence of significant differences in Hsp60 levels assessed immunohistochemically between patients with mild periodontitis and healthy controls in both epithelium and lamina propria. The images are representative of Hsp60 levels in epithelium (a and b) and lamina propria (c and d) in healthy subjects (a and c) and patients with mild periodontitis (b and d). Bar: 50 microns. e Histogram showing results of semiquantitative evaluation of Hsp60 immunostaining. Vertical axis, semiquantitative scale measuring amount of Hsp60 positivity in the tissue; n.s. not significant