Eosinophils during developing periodontal disease of rats

Periodontal structures in horses with pituitary pars intermedia dysfunction: A histological evaluation

Introduction

Pituitary pars intermedia dysfunction (PPID) and dental disorders are of major concern in horses older than 15 years. Although PPID in geriatric horses and dental disorders in all age groups are well described, a connection between this endocrine disease and pathological changes in equine dental structures has not yet been investigated. In humans, periodontitis is considered to be a complication of systemic diseases like diabetes mellitus type 2, obesity and various conditions leading to an impaired immune response. In PPID, cross links to insulin and immune dysregulations are proven. The aim of this study was to compare histological findings of the gingiva and the sub gingival periodontal ligament of PPID affected horses with control horses.

Methods

In a case-control morphometric descriptive study, 145 dental locations of 10 PPID affected horses (27.3 ± 2.06 years) were compared with 147 dental locations of 10 controls (21.4 ± 4.12 years). Histological parameters were leukocyte infiltration, keratinization of gingival epithelium, blood vessel supply of the periodontium and structure of cementum.

Results

The distribution and localization of gingival leukocyte infiltrations (LI) in PPID affected horses was more often multifocal to coalescing (p = 0.002) and reached into deeper parts of the periodontium, sometimes down to the sub gingival periodontal ligament (PDL). Aged animals of both groups showed higher prevalence (PPID: OR 1.66; controls: OR 1.15) for severe leukocyte infiltration in the PDL. PPID was not significantly associated with increased LI. The cementum bordering the soft tissue in interdental locations showed four times more irregularities in PPID affected horses than in controls which predisposes for interdental food impaction and periodontal diseases.

Discussion

In summary, multifocal to coalescing leukocytes and irregular cementum are seen more often in PPID than in controls - however our findings mainly reflect an association of older age with periodontal disease.

Impact of citrus flavonoid supplementation on inflammation in lipopolysaccharide-induced periodontal disease in mice

In general, the consumption of flavonoid-rich foods may influence the control/dysregulation of the magnitude and duration of inflammation and oxidative stress, which are known to contribute to multiple pathologies. Information regarding the impact of citrus flavonoid dietary supplementation on periodontal disease is still scarce. Herein, we investigated whether a diet supplemented with eriocitrin and eriodictyol could alter the course of the inflammatory response associated with LPS-induced periodontal disease in mice. Sixty BALB/c mice received a standard diet or a diet supplemented with different concentrations of eriocitrin or eriodictyol. After 30 days of food supplementation, a solution containing LPS from Escherichia coli was injected into the gingival tissues three times per week for four weeks. Neutrophils, mononuclear cells and eosinophils were assessed using a severity analysis system in H&E-stained sections and modified picrosirius red. The activities of myeloperoxidase (MPO), a marker of granulocyte infiltration, and eosinophil peroxidase (EPO) were determined spectrophotometrically. The oxidative damage was determined by measuring the malondialdehyde (MDA) content and anti-oxidative activity through the assessment of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interleukin (IL)-1β, TNF-α, and IL-10 were quantified by multiplex immunoassay. Periodontal inflammation was significantly inhibited by citrus flavonoid supplementation, including reduced flatness of the gingival epithelium and chronic and acute inflammatory cell infiltration, as well as loss of connective tissue in the gingival papillae. Both eriocitrin and eriodictyol inhibited gingival IL-1β and TNF-α and increased IL-10 secondary to periodontitis. Significant protection and decreased MPO and EPO activity were detected in the periodontal tissue of citrus flavonoid-treated animals. In comparison with the LPS group, SOD, CAT and GPx activities were increased, while the MDA content was reduced, indicating decreased oxidative damage. These results suggest that a diet supplemented with the citrus flavonoids eriocitrin or eriodictyol may aid in the prevention of periodontitis, representing a potential method to enhance local immunity and host defense.

Histopathological lesions associated with equine periodontal disease

Equine periodontal disease (EPD) is a common and painful condition, the aetiology and pathology of which are poorly understood. To characterise the histopathological lesions associated with EPD, the skulls of 22 horses were assessed grossly for the presence of periodontal disease, and a standard set of interdental tissues taken from each for histopathological examination. Histological features of EPD included ulceration and neutrophilic inflammation of the gingival epithelium. Mononuclear and eosinophilic inflammation of the gingival lamina propria and submucosa was commonly present irrespective of the presence or degree of periodontal disease. Gingival hyperplasia was present to some degree in all horses, and was only weakly associated with the degree of periodontal disease. In all horses dental plaque was present at the majority of sites examined and was often associated with histological evidence of peripheral cemental erosion. Bacteria (including spirochaetes in four horses) were identified in gingival samples by Gram and silver impregnation techniques and were significantly associated with the presence of periodontal disease. This is the first study to describe histological features of EPD, and the first to identify associated spirochaetes in some cases. Histological features were variable, and there was considerable overlap of some features between the normal and diseased gingiva. Further investigation into the potential role of bacteria in the pathogenesis and progression of EPD is warranted.