Porphyromonas gingivalis (W83) Infection Induces Alzheimer's Disease-Like Pathophysiology in Obese and Diabetic Mice.

BACKGROUND: Periodontal disease(s) and metabolic illnesses negatively impact the quality of life and, eventually mental health. OBJECTIVE: This study investigated the effect of Porphyromonas gingivalis (W83) oral infection on the development of Alzheimer's disease (AD) pathophysiology in a wild-type obese, diabetic (db/db) mouse model. METHODS: The db/db mice were either orally infected with P. gingivalis and Fusobacterium nucleatum or sham infected for 16 weeks. The presence of amyloid-ß (Aß) and neurofibrillary tangles (NFTs) were assessed using a silver impregnation technique and subsequently by immunohistochemistry for tau and neuroinflammation. The mRNA abundance of a panel of 184 genes was performed using quantitative real-time PCR, and the differentially expressed genes were analyzed by Ingenuity Pathway Analysis. RESULTS: While no Aß plaques and NFTs were evident by silver impregnation, immunohistochemistry (glial cell markers) of the P. gingivalis-infected mice tissue sections exhibited neuroinflammation in the form of reactive microglia and astrocytes. Anti-tau immunopositivity, in addition to cells, was prominent in thickened axons of hippocampal CA neurons. The mRNA abundance of crucial genes in the insulin signaling pathway (INSR, IGF1, IRS, IDE, PIK3R, SGK1, GYS, GSK3B, AKT1) were upregulated, potentially exacerbating insulin resistance in the brain by P. gingivalis oral infection. Increased mRNA abundance of several kinases, membrane receptors, transcription factors, and pro-inflammatory mediators indicated hyperactivation of intracellular cascades with potential for tau phosphorylation and Aß release in the same infection group. CONCLUSION: P. gingivalis W83 infection of db/db mice provides a disease co-morbidity model with the potential to reproduce AD pathophysiology with induced periodontal disease.

Porphyromonas gingivalis induces depression via downregulating p75NTR-mediated BDNF maturation in astrocytes.

Many cross-sectional epidemiological studies have shown the incidence of periodontitis is positive correlated with that of depression. However, their causal relationship and underlying mechanism are largely unknown. Porphyromonas gingivalis (Pg) is the main pathogen for periodontitis. Employing female mice treated with Pg every other day for 4 weeks, we found that Pg-mice showed obvious depression-like behavior, an increased number of activated astrocytes and decreased levels of mature brain derived neurotrophic factor (BDNF) and astrocytic p75NTR in the hippocampus. Both hippocampal injection of BDNF and overexpression of p75NTR in astrocytes alleviated Pg-induced depression-like behavior in mice. Moreover, Pg-lipopolysaccharides (LPS) generated similar phenotypes, which were reversed by the TLR-4 inhibitor TAK242. Our results suggest that Pg-LPS decreases the level of astrocytic p75NTR and then downregulates BDNF maturation, leading to depression-like behavior in mice. Our study provides the first evidence that Pg is a modifiable risk factor for depression and uncovers a novel therapeutic target for the treatment of depression.

Treatment, outcome and quality of life after Fournier's gangrene: a multicentre study.

AIM: The object of this study was to describe the course of Fournier's gangrene and assess quality of life in a group of affected patients. METHOD: We evaluated patients who received inpatient treatment for Fournier's gangrene at five hospitals in northern Germany from 1995 to 2010. Surviving patients were asked to take part in a clinical follow-up and complete the Short-Form 36 (SF-36) quality-of-life questionnaire and a disease-specific questionnaire including a physical examination. RESULTS: Of the 86 patients, 72 (83.7%) were men. The mean age of the patients was 57.9 ± 13.9 (25-89) years. The mean length of hospital stay was 52.0 ± 54.0 (1-329) days. Fourteen (16.3%) patients (eight men) died primarily from Fournier's gangrene. The most common aetiological event was anogenital abscess formation (n = 24; 27.9%). Seventy-one (82.5%) patients had a mixed polymicrobial infection. SF-36 physical role functioning (P = 0.010), physical functioning (P = 0.008), general health (P = 0.010) and physical health summary (P = 0.006) scores were significantly lower than those of the normal population. Deterioration in sexual function was reported by 65% of the patients. CONCLUSION: Patients with Fournier's gangrene experience persistent physical and mental health problems for a long period of time following their primary hospital stay and must receive long-term care from a variety of specialists, otherwise the disease leads to an increase in the duration of morbidity and a decrease in quality of life.