Periodontitis aggravates kidney damage in obese mice by MMP2 regulation

OBJECTIVE

  To investigate the effect of periodontitis on the development of kidney damage in obese mice and its possible mechanism.

METHODS

  C57 BL/6J mice were fed high‑fat (HF) or low‑fat (LF) diet and then divided into four groups:  obesity with periodontitis (HFP), obesity without periodontitis (HFC), normal mice with periodontitis (LFP) and normal mice without periodontitis (LFC). Serum indicators of renal function, namely serum total protein (TP), albumin (ALB), creatinine (Cr) and blood urea nitrogen (UREA) were measured. The histopathological examination of kidney tissues was performed. The expressions of transforming growth factor-β1 (TGF-β1), matrix metalloproteinase-2 (MMP2) and tissue inhibitors of metalloproteinases-1 (TIMP1) were detected by immunohistochemistry and real time RT-PCR.

RESULTS

  Obesity decreased TP and ALB, and increased serum Cr and UREA levels in normal and periodontitis mice groups, as well as induced glomerular and tubulointerstitial pathologic changes. Tubulointerstitial fibrosis was more severe in HFP group. In obese mice, periodontitis caused the downregulation of MMP2, and upregulation of TIMP1 and TGF-β1 at transcriptional and translational levels.

CONCLUSIONS

  In obese mice, periodontitis may aggravate pathological changes in the kidney. The possible mechanism might lie in downregulation of MMP2 and upregulation of MMP inhibitor, TIMP1, and TGF-β1 (Tab. 1, Fig. 4, Ref. 16).

Histological changes within dental pulps in teeth with moderate-to-severe chronic periodontitis

AIM

To investigate the effect of chronic periodontitis on dental pulps by assessing histological changes in the pulps of teeth with moderate-to-severe periodontitis.

METHODOLOGY

A total of 242 teeth from 162 patients with moderate-to-severe periodontitis were collected, and histological changes in pulps were investigated by staining with haematoxylin and eosin. Baseline data were taken from the patients' records before extraction. The morphologic changes observed in the pulp were classified as degree I, degree II, degree III and degree IV. Statistical analysis of the severity of periodontitis and histological changes with the pulps was applied using the Mann-Whitney U rank sum test, whilst the contingency coefficient was used to analyse the inter-relationship between the severity of periodontitis and histological changes in the pulps.

RESULTS

The inter-relationship between the severity of periodontitis and histological changes in the pulps was 0.274 (P < 0.001), and significant differences existed between teeth with moderate periodontitis and severe periodontitis group (Z = 4.145, P < 0.001). The inter-relationship between attachment loss and histological changes in the pulps was 0.397 (P < 0.001). There were significant differences in the histological changes amongst teeth with various degrees of attachment loss (χ(2) = 33.023, P < 0.001) and amongst teeth in different locations (χ(2) = 23.163, P < 0.001).

CONCLUSIONS

There was a positive association between the severity of periodontitis and histological changes within the pulp. More attachment loss was correlated with pathological changes within the dental pulp.